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SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B 9/02 ; treatment of water C02F, e.g. softening by ion-exchange C02F 1/42 ; { arrangements of air intake cleaners in gas turbine plants F02C 7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F 13/28)
Definition statement
This subclass covers:

Processes and apparatus for evaporation, distillation, sublimation, crystallisation, solvent extraction, chromatography, sedimentation, filtration, dust precipitation, gas cleaning, absorption, adsorption, separation of isotopes.

Cold traps, cold baffles.

Treating liquids by displacement, adsorption, separation or degasification.

Treating gases or vapours by separation, recovering, chemical or biological purification of waste gases.

Separation using semi-permeable membranes, dialysis, osmosis, ultrafiltration.

Separation of suspended particles from liquids by sedimentation, flocculation, settling, filtration or other processes.

Separation of dispersed particles from gases or vapours, by filtration, gravity, inertia or centrifugal forces, or using liquid as separating agent.

Similar processes which are not concerned with, or limited to, separation.

Relationship between large subject matter areas

For apparatus used in drying or evaporation, F26B takes precedence over this subclass.

Separation of isotopes of the same chemical element is covered by group B01D 59/00, whatever process or apparatus is employed; this group therefore takes precedence over other groups of class B01.

References relevant to classification in this subclass
This subclass does not cover:

Separating solids from solids by wet methods

Separating solids from solids using liquids or using pneumatic jigs or tables

Magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields

Flotation, differential sedimentation

Separating solids from solids by dry methods, e.g. sieving, screening, sifting or using gas currents

Centrifuges

Vortex apparatus, e.g. cyclones

Presses per se for squeezing-out liquid from liquid-containing material

Treatment of water

Treatment of water softening by ion-exchange

Making single crystals

Into single crystals

Manufacture of hollow fibres

of air intake cleaners in gas turbine plants

Arrangements or mounting of filters in air-conditioning, air-humidification or ventilation

Separation of difficult-to-condense gases or air by liquefaction

Condensers

Examples of places where the subject matter of this class is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Blood or infusion liquid filters

Screens or sieves per se

Extrusion filters

Filtering spinning solution or melt

Filtration of lubricants

Suction cleaner filters

Filters for breathing-protection purposes

Filtering air for vehicles

Separating pneumatically-conveyed materials from propelling gas

Exhaust or silencing apparatus for machines or engines having means for removing solid constituents of exhaust

Air cleaners for the intakes of gas-turbine or jet-propulsion plants

Air cleaners for the intakes of combustion engines

Air cleaners for the intakes of compressors

Filtering in air-conditioning

Arrangement or mounting of filters in air-conditioning, air-humidification or ventilation

Purification or separation of nitrogen

Working-up unidentified gaseous mixtures obtained by cracking hydrocarbon oils

Cleaning coal gas

Working-up of natural gas, or synthetic natural gas

Investigating materials

Treatment of milk by dialysis, reverse osmosis or ultrafiltration

Treatment of milk by electrodialysis

Artificial kidneys

Treatment of water e.g. softening of water by ion-exchange

Treatment of water by dialysis, osmosis or reverse osmosis

Treatment of water by electrodialysis

Apparatus for enzymology or microbiology with dialysis means

Production or purification of sugar juices, e.g. by osmosis

C13D3/16

Extraction of sugar from molasses, e.g. by osmosis

C13J1/08

Diaphragms for electrolysis

Osmosis as energy source

Special rules of classification within this subclass/group

Group B01D 59/00 (separation of isotopes) takes precedence over other groups of this subclass since it covers separation of isotopes of the same chemical element, whatever process or apparatus is employed.

Glossary of terms
In this subclass, the following terms (or expressions) are used with the meaning indicated:

Filtration

The separation of a fluid-solid mixture, involving passage of most of the fluid through a porous barrier which retains most of the solid particulates contained in the mixture; includes straining solids from fluids.

Filter medium

A porous barrier or porous arrangement of material, which lets a fluid pass while retaining most of the solids which were mixed with it.

Filtering element

A section of filter medium in addition to parts to which the medium is demountably or permanently fixed, including other sections of medium, end caps, peripheral frames or edge strips, but excluding housings.

Filter housing

The fluid-constraining impervious vessel, whether open or closed, which contains, or is adapted to contain one or more filtering elements or filter media.

Filter chamber

The space within a housing where filtering elements or filter media are located; partitions may divide a single housing into a plurality of chambers.

Filtering apparatus

Filtering elements combined with housings, cleaning arrangements, motor or like parts, which are characteristic of the particular type of apparatus. Ancillary devices such as pumps or valves are considered part of a filtering apparatus when inside the apparatus. Ancillary devices performing similar or different unit operations such as comminutors, mixers or non-filtering separators, whether or not inside the apparatus, are not considered part of a filtering apparatus. The term does not extend to apparatus, e.g. washing machines, of which the filter forms only a part.

Evaporating ({evaporation in general, e.g. of liquids for gas phase reactions B01B 1/005} ; removal of incrustation B08B; preparation of starch C08B 30/00 ; sugar industry C13; prevention of incrustation C23F; drying solid materials or objects by evaporating liquids therefrom F26)
Definition statement
This group covers:

This group covers document where evaporation of a mixture is used for separation of components of said mixture.

Document concerning specific application should not be classified in this group.

Means for contacting gas and liquid for the specific purpose of concentration by evaporation

This group does not cover :

Evaporation and concentration with attendant crystallisation is not classified in this group.

Relationship between large subject matter areas

Concentrating by evaporation of liquid containing solids in solution or suspension and treating or recovering the concentrate are classified in B01D 21/00 and F26

Recovery of heat in the vapours evolved is classify in B01D 5/006

References relevant to classification in this group
This group does not cover:

Evaporation without separation

evaporation in general, e.g. of liquids for gas phase reactions

Distillation

removal of incrustation

preparation of starch

sugar industry

C13

prevention of incrustation

drying solid materials or objects by evaporating liquids therefrom

F26

Informative references
Attention is drawn to the following places, which may be of interest for search:

food evaporation

soups concentration

juices evaporation

removal of incrustation

Water evaporation

preparation of starch

In sugar industry

Preventing incrustation

spent liquor concentration

Drying solid materials or objects by evpoarating liquids therefrom

heat exchanger construction

{Use of electrical or wave energy (B01D 1/0029 takes precedence)}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Microwave devices

{Solar energy (for treatment of water C02F 1/14)}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Water

{by film evaporating}
Definition statement
This subgroup covers:

Evaporators with vertical tubes by film evaporating , e.g. documents describing a falling-film evaporator.

This subgroup does not cover the following:

Rising-film and wiped-film evaporators

Liquid being maintained as a film on a support by centrifugal force

Film supported on a travelling surface for evaporation

Informative references
Attention is drawn to the following places, which may be of interest for search:

Gas and liquid contact in film

Boilers, e.g.

Machines or apparatus for drying materials in loose, plastic or fluidised form

Heat exchanger

to obtain dry solids (B01D 1/24 takes precedence)
Definition statement
This subgroup covers:

This class is for classifying documents where the feed is a liquid mixture and after treatment a stream of vapour is obtained as well as some solid(s).

References relevant to classification in this group
This subgroup does not cover:

Evaporating to obtain dry solids

Informative references
Attention is drawn to the following places, which may be of interest for search:

Granulation

Solid drying

Sprayers (in general B05B)
Informative references
Attention is drawn to the following places, which may be of interest for search:

Distillation in spray form

Sprayers

to obtain dry solids
Definition statement
This subgroup covers:

This group is for classifying documents where the feed is a liquid mixture and after treatment a stream of vapour is obtained as well as some solid(s).

Informative references
Attention is drawn to the following places, which may be of interest for search:

Granulation

Solid drying

with vapour compression
Informative references
Attention is drawn to the following places, which may be of interest for search:

Distillation using compresses vapour as source of heat

Water

Compressor

Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping ({evaporation in general, e.g. of liquids for gas phase reactions B01B 1/005} ; gas chromatography B01D 15/08 ; destructive distillation C10B ; preparation of alcoholic beverages by distillation C12G 3/12)
Definition statement
This group covers:

This group concerns distillation in general. Specific application should classified in the relevant group.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Evaporation of liquids for gas phases reactions

Gas chromatography

Destructive distillation (pyrolysis)

Preparation of alcoholic beverages by distillation

Special rules of classification within this group

Packing elements are classified in B01J 19/30, B01J 19/32 and corresponding Indexing Codes.

Documents with a simple reference to distillation as possible separation means or step should not be classified in B01D 3/00.

{Processes specially adapted for distillation or rectification of fermented solutions}
Definition statement
This subgroup covers:

In B01D 3/001 are classified the documents dealing with alcohol batch distillation.

Informative references
Attention is drawn to the following places, which may be of interest for search:

More general alcohol distillation processes

Preparation of alcoholic beverages by distillation

{by continuous methods}
Definition statement
This subgroup covers:

In B01D 3/001 are classified the documents dealing with alcohol continuous distillation.

{Rectification of spirit}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Preparation of alcoholic beverages other that wine by distillation

{Liquid distribution}
Special rules of classification within this group

Liquid feeder/distributor for all kind of columns (absorption) should be classified here.

{in combination with chemical reactions}
Definition statement
This subgroup covers:

The chemical reaction is inside the distillation vessel.

This subgroup does not cover:

The chemical reaction only for assisting in the separation by distillation of a pre-existing

Informative references
Attention is drawn to the following places, which may be of interest for search:

Distillation using compresses vapour as source of heat

Purification, separation of hydrocarbons

Destructive distillation of carbonaceous materials for production of gas, coke

Working up tar, pitch, asphalt by chemical means

{using a rotary evaporator}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Distillation using compresses vapour as source of heat

Laboratory apparatus

Machines or apparatus for drying solid materials with movements which is non-progressive

Fractional distillation {or use of a fractionation or rectification column}
Glossary of terms
In this subgroup, the following terms (or expressions) are used with the meaning indicated:

In patent documents the following expressions/words "Fractionation","rectification" and "distillation" are often used as synonyms.

Extractive distillation
References relevant to classification in this group
This subgroup does not cover:

Azeotropic distillation

Informative references
Attention is drawn to the following places, which may be of interest for search:

Extraction

Condensation of vapours; Recovering volatile solvents by condensation (B01D 8/00 takes precedence; condensers F28B)
References relevant to classification in this group
This group does not cover:

condensers

Informative references
Attention is drawn to the following places, which may be of interest for search:

Distillation

Condensation from gases

Water condensation from air

Heat exchanger construction

{by using heat-exchange surfaces for indirect contact between gases or vapours and the cooling medium}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Heat exchanger construction

Sublimation (B01D 8/00 takes precedence; freeze-drying F26)
Definition statement
This group covers:

Sublimation or antisublimation in general for separation.

References relevant to classification in this group
This group does not cover:

Cold traps; cold baffles

Freeze-drying

F26

Informative references
Attention is drawn to the following places, which may be of interest for search:

Cryogenic separation

Drying solids

Distillation

Special rules of classification within this group

Specific application should be classified in the relevant groups.

Cold traps; Cold baffles (pumps for evacuating by condensing or freezing F04B 37/08)
Definition statement
This group covers:

Only documents for separation should be classified in this group.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Pumps for evacuating by condensing or freezing

Cryogenic separation

Crystallisation (crystallisation directly from the vapour phase B01D 7/02 ; making single crystals C30B ; { crystallisation as part of the Bayer process also classified in C01F 7/14})
Relationship between large subject matter areas

Making single crystals: C30B

References relevant to classification in this group
This group does not cover:

Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuff: fractionated crystallisation

Dairy products, e.g. milk, butter, cheese; milk or cheese substitutes: Concentration by freezing out the water

Production of sucrose; apparatus specially adapted therefor: Crystallisation; Crystallising apparatus; Separating crystals from mother liquors

Medicinal preparations characterised by special physical form: Agglomerates; Granulates; Microbeadlets : Processes

Investigating or analyzing materials by crystallisation

Purification/separation of acyclic or carbocyclic compounds by crystallisation

Treatment of water, waste water or sewage by freezing

Crystallisation as part of the Bayer process is also classified in

Crystallisation directly from the vapour phase

Informative references
Attention is drawn to the following places, which may be of interest for search:

Processes leading to the formation of precipitates

Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuff: by drying or kilning

Special rules of classification within this group

No documents should be classified in B01D 9/02 as virtually all crystallisation processes are conducted using solutions of the target compound. Use B01D 9/04 if solvent is removed for concentration of solutions.

Solvent extraction
References relevant to classification in this group
This group does not cover:

Separation of isotopes by solvent extraction

Production of fats/fatty oils by extraction

Recovery/refining of essential oils/perfumes by solvent extraction

Purification/separation of acyclic or carbocyclic compounds by extraction

Refining of hydrocarbon oils in the absence of hydrogen, by extraction with selective solvents

Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal, by extraction

Extraction of metal compounds from ores or concentrates by wet processes

Working-up pitch, asphalt, bitumen by selective extraction

Working-up used lubricants to recover useful products using extraction processes; apparatus therefor

Coffee: reducing alkaloid content by extraction of the beans with selective solvents other than water or aqueous bean extracts, including supercritical gases

Coffee: reducing alkaloid content by extraction of the beans with water, aqueous solutions without organic or inorganic solvents, or aqueous coffee extract

Extraction of coffee; Coffee extracts

Foods or foodstuffs; their preparation or treatment : plant extracts

Foods or foodstuffs; their preparation or treatment: natural spices obtained by solvent extraction

Cosmetic or similar toilet preparations containing material of vegetable origin, e.g. plant extracts

Tea extraction

Extraction of hop using carbon dioxide

Treating radioactively contaminated material by solvent extraction

Treatment of water, waste water or sewage by extraction

Separation/purification of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by liquid-liquid treatment

Preparation of oxyacids of phosphorus involving liquid-liquid extraction

Informative references
Attention is drawn to the following places, which may be of interest for search:

Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; processes carried out under supercritical conditions

Cleaning using liquid gasses or supercritical fluids

Heating using microwaves

Preparing specimens for investigation: purifying, cleaning

Medicinal preparations containing material or reaction products thereof with undetermined constitution

Medicinal preparations of undetermined constitution containing material from algae, lichens, fungi or plants, or derivatives thereof, e.g. traditional herbal medicines

Cleaning electronic devices, e.g. semiconductors

Displacing liquid, e.g. from wet solids or from dispersions of liquids or from solids in liquids, by means of another liquid
Relationship between large subject matter areas

Displacing liquid normally aims at drying the solids and in this case should not be classified here, but rather in F26B 5/005 (see below).

References relevant to classification in this group
This group does not cover:

Drying solid materials or objects by dipping them into or mixing them with a chemical liquid, e.g. organic; chemical, e.g. organic, dewatering aid

Separating processes involving the treatment of liquids with solid sorbents (using liquid sorbents B01D 11/00 ; ion exchange processes or materials, sorbent materials in general B01J, e.g. sorbents for chromatography B01J 20/281 ; for investigating or analysing materials G01N 30/00); Apparatus therefor
Definition statement
This group covers:
  • Separating processes and apparatus for treating liquids involving non-selective adsorption with solid sorbents.
  • Separating processes and apparatus for treating liquids involving moving solid sorbents.
  • Separation processes and apparatus for treating liquids using selective adsorption, e.g. chromatography.
  • Processes for separation by chromatography involving ion exchange materials and apparatus therefor.
References relevant to classification in this group
This group does not cover:

Sorbent materials

Sorbents used as stationary phases or packings for chromatography

Investigative or analytical chromatography

Treatment processes of water by sorption

Treatment of water by ion-exchange

Ion-exchange processes or materials

Ion-exchange materials used for chromatographic processes

Preparative gas chromatography

Separating processes involving the treatment of liquids with liquid sorbents

Separation of isotopes of the same chemical element

Informative references
Attention is drawn to the following places, which may be of interest for search:

Modifying dairy products by dialysis, osmosis, filtration or ion-exchange

Treating blood or products derived there from

Separation of optically active compounds

Purification of hydrocarbons by adsorption

Extraction, separation or purification of peptides by chromatography

Processes for the isolation, preparation or purification of DNA or RNA

Working-up of used lubricants with the use of adsorbents

Refining hydrocarbon oils with solid sorbents

Refining fats or fatty oils by adsorption

Purification of alcoholic beverages with ion-exchange or adsorption materials

Separating or purifying micro-organisms or enzymes

Purification of sugar juices using adsorption agents

Treating radioactively contaminated liquids by adsorption

Medicinal preparations of undetermined constitution containing material from algae, lichens, fungi or plants, or derivatives thereof, e.g. traditional herbal medicines

Special rules of classification within this subclass/group
  • B01D 15/00 or B01D 15/02 are to be used for classifying non selective adsorption processes or apparatus other than chromatography involving the removal of a particular component from a liquid, e.g. removal of heavy metals such as mercury, sulphur containing compounds , PCB's from e.g. a hydrocarbon feedstock, a solvent, a caustic solution.
  • Separation or purification processes by chromatography are classified in B01D 15/26 and subgroups according to the separation mechanism.
  • Specific features related to chromatography processes or apparatus are classified in B01D 15/10 and subgroups.
  • The IPC group B01D15/04 is not used in the CPC classification scheme. Subject-matter covered by this group is classified in B01J 39/00 to B01J 49/02.
  • In order that group B01D 15/08 may provide a basis for a complete search with respect to chromatography in general, all subject matter of general interest is classified in this group even if it is classified primarily in the application-oriented groups, for example dairy products A23C 9/148, treatment of blood, e.g. A61M 1/36, optically active organic compounds C07B 57/00 or peptides C07K 1/16 (See Informative references).
  • Other secondary non invention related information concerning chromatography can be classified with symbols B01D 15/08-B01D 15/428.
  • Moreover, combination of these Indexing Code symbols should also be used when classifying documents relating to chromatographic processes involving several different type of interactions. For example, a multistep chromatographic process involving hydrophobic interaction chromatography followed by ion exchange chromatography should be classified in (B01D 15/327,B01D 15/361). A process using affinity chromatography followed by chromatography with an anion exchanger should be classified in (B01D 15/3804,B01D 15/363).
Glossary of terms
In this group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

Adsorption

Separation process which involves the transfer and resulting equilibrium distribution of one or more solutes between a fluid phase and adsorbing particles.

Sorbent

A material which separates a constituent from a fluid mixture containing such constituents. The action in most instances is that of selective retention (i.e. the sorbent removes only the part of the fluid mixture for which it has the greatest affinity). The retained constituent cannot be removed by shaking, brushing or similar mechanical action, but generally can be removed by heating, pressure reduction, or use of a stripping or denuding fluid.

Chromatography

A process in which a liquid is flowed along a linear path comprising a sorbent, with which the liquid competes in affinity for a constituent of the liquid. The constituent is sorbed from the moving liquid by the relatively immobile sorbent and re-dissolved by a later passing portion of the liquid until an equilibrium of the sorbing-dissolving step is set up causing the constituent to concentrate in a specific volume of the sorbent and to move along the path of the liquid at a rate slower than such liquid.

Adsorption chromatography:

Separation is based mainly on the differences between the adsorption affinities of the sample components for the surface of an active solid.

Partition chromatography

Separation is based mainly on differences between the solubilities of the sample components in the stationary phase (gas chromatography) or on differences between the solubilities of the components in the mobile and stationary phases (liquid chromatography).

Exclusion chromatography

Separation is based mainly on exclusion effects, such as differences in molecular size ( size- exclusion chromatography) and/or shape or charge.

Affinity chromatography

The particular variant of chromatography in which the unique biological specificity of the analyte and ligand interaction is utilised in the separation.

Bonded phase

A stationary phase which is covalently bonded to the support particles or to the inside wall of the column tubing.

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

HPLC

High performance liquid chromatography, sometimes also referred to as high pressure liquid chromatography.

Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion (devices for separating or removing fatty or oily substances or similar floating material from water, waste water, or sewage C02F 1/40 ; cleaning or keeping clear the surface of open water from oil or like materials E02B 15/04 ; arrangements for separating lubricants from refrigerants F25B 43/02)
Definition statement
This group covers:

Documents concerning separation of liquids not provided elsewhere should be given a group in B01D 17/00. In case of specific application, the document should be given a group in the relevant field only.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Blood treatment

Liquid solid separation

Filtration

For cyclones

Petrol separation

Fat separation

Drilling or well fluid separation

Drying solid

Waste water treatment

For cleaning open water from oil

Separating lubricants from refrigerants

Special rules of classification within this group

In the case of a document in the specific field of water treatment, the document should be given a the classification symbol B01D 17/00.

The wording of the title of the group could allow classification of documents for separation of miscible liquids. In practice only documents with separation of emulsion is classified in this group. Separation of miscible liquids should be classified in the relevant group(s) e.g. evaporation (B01D 1/00), distillation (B01D 3/00), permeation (B01D 61/00), filtration (B01D 39/00).

This group used combination of classes. This has been abandoned but reclassification is currently done.

If the phase to be separated comprises also solids (liquid-liquid-solid stream) and the separation step separates the three phases in three streams, then it should be classified in the relevant group in B01D 21/00.

{by gas bubbles or moving solids}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Flotation

{by centrifugal force}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Cyclones

{with coalescers}
Definition statement
This subgroup covers:

Devices (or processes) with some grid for increasing coalescing of phases. The grid can have lipophilic or lipophobic composition.

{with separation aids}
Definition statement
This subgroup covers:

Addition of a chemical agent to promote the separation of the phases.

{by changing the state of aggregation}
Definition statement
This subgroup covers:

Documents describing inversion of phases (O/W to W/O and reciprocally) should be classified in this group

Separation of liquids from each other by electricity
Informative references
Attention is drawn to the following places, which may be of interest for search:

Magnetic or electrostatic separation

Microwave devices

Degasification of liquids
Definition statement
This group covers:

Documents involving degassing of a liquid should be given a group in this field. The constituent that is removed from the liquid is initially present in the liquid as a gas, e.g. air, oxygen, nitrogen, carbon dioxide, etc.

Degassing includes defoaming (B01D 19/02) and also stripping a gas from a liquid that was used in absorption of a gas from another gas (B01D 19/00).

Vaporising a liquid mixed in another liquid and then removing the vaporised liquid (now a gas) is not removing a constituent initially present as a gas from a liquid.

Degassing is B01D 19/00 and separation by evaporation is B01D 1/00

Informative references
Attention is drawn to the following places, which may be of interest for search:

Blood treatment

Cyclones

Filtration

Ink degassing

Special rules of classification within this group

In practice, all documents about degassing of ink(s) are classified only in B41J 2/19.

{Flash degasification (the other groups take precedence)}
Definition statement
This subgroup covers:

Documents involving degassing by vacuum should be given this group.

The other groups in B01D 19/00 take precedence

{the centrifugal movement being caused by a vortex, e.g. using a cyclone, or by a tangential inlet}
Definition statement
This subgroup covers:

Degasification of liquids by modifying the liquid flow in vessels in which the centrifugal movement is caused by a vortex

Informative references
Attention is drawn to the following places, which may be of interest for search:

Cyclones

{Regulation, control including valves and floats (for construction and details of valves F16K)}
Informative references
Attention is drawn to the following places, which may be of interest for search:

For detail of valves see

{using an electric current}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Electrostatic separation

Microwave devices

{using a magnetic field (magnetic separation in general B03C 1/00)}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Magnetic or electrostatic separation

Magnetic separation in general

Microwave devices

{by using a vortex, cavitation}
Definition statement
This subgroup covers:

Degasification of liquids by a method not covered by groups B01D 19/0005 to B01D 19/0042 and using a vortex

Informative references
Attention is drawn to the following places, which may be of interest for search:

Ultrasonic devices

Cyclones

Foam dispersion or prevention (during boiling B01B 1/02 ; during fermentation C12)
Informative references
Attention is drawn to the following places, which may be of interest for search:

Foam dispersion or prevention during boiling without separation

Foam dispersion or prevention during fermentation

Separation of suspended solid particles from liquids by sedimentation ({separation of ores or the like by sedimentation B03B 5/48 to B03B 5/60} ; differential sedimentation B03D 3/00 ; {purification of water, waste water, sewage or sludge C02F, e.g.} devices for separating or removing fatty or oily substances or similar floating material from water, waste water or sewage C02F 1/40)
Definition statement
This group covers:
  • Devices for the separation of suspended solid particles from liquids by sedimentation in general, i.e., if the application of the device is subordinate.
  • Devices for specific applications if there is a strong emphasis on the structural details of the device or if parts of the device are of general interest in the field of sedimentation. For example, a sedimentation device for waste water treatment, also classified in C02F, which discloses e.g. certain details of the scraper, should also be classified in B01D 21/00.
Relationship between large subject matter areas

Documents which are primordially directed to the fields of waste water treatment (C02F), sewers (E03F) or other technical fields relating to the application of the apparatuses should only be classified in B01D 21/00 if the device disclosed therein shows structural details of general interest in B01D 21/00. Documents disclosing the mere presence of a sedimentation device, e.g. as a schematic block in a process flow diagram, as a schematic drawing after a sand filter etc., should not be classified in B01D 21/00. Instead, an appropriate index from the indexing scheme corresponding to B01D 21/00 should be assigned.

Documents disclosing a device relating to the technical the fields of the separation with centrifuges (B04B), the separation with free vortices, e.g. cyclones (B04C), the electric and magnetic separation (B03C), the filtration (B01D 23/00 to B01D 41/00), the flotation (B03D 1/00) or the differential sedimentation (B03D 3/00) should only be classified in B01D 21/00 if the general aspects of the disclosed device relate to B01D 21/00 and if it is deemed unjustified to assign a classification symbol in the respective other fields. This is normally the case if the disclosure lacks sufficient structural details to justify a classification in the above referred technical fields be assigned or because the feature relates to a side aspect. Examples for side aspects are the rough pre-filtration of the liquid to be clarified by sedimentation, the mere presence of a magnetic separator at an outlet of the sedimentation tank, or the introduction of gas bubbles in a limited region of the sedimentation device, e.g. close to the discharge opening for the clarified liquid.

References relevant to classification in this group
This group does not cover:

Separation of liquids by sedimentation or centrifugal forces

Washing granular materials; Separating solids from solids by wet methods e.g. sink-float separation: separating the fractions of a mixture of solids with a liquid having a density in between the fractions

Magnetic or electrostatic separation devices

Flotation devices (also reactor-separator types)

Differential sedimentation: separating a mixture into its fractions by making use of a difference in sedimentation velocity, e.g. density gradient centrifugation

Centrifuges and structural details thereof

Cyclones and structural details thereof

Treatment of water, waste water, sewage, or sludge when no structural details of general interest are disclosed.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Treating manure

Devices used for fish ponds

Treatment of water for aquaria

Processing slaughtering residues

Clarifying non-alcoholic beverages

Sedimentation devices for dental use

Sedimentation devices for medical purposes, body liquids

Filters making use of electricity or magnetism

Chemical or physical processes

Paint sludge treatment

Methods or apparatus specially adapted for transmitting mechanical vibrations

Removing chips from sawing machines

Removing chips from machine tools

Ink filters for printers

Barges for collection of pollution from open water

Fluidising means for discharging large containers

Treatment of water, waste water, sewage, or sludge when structural details of general interest are disclosed.

Refining hydrocarbon oils by centrifugation

Working-up lubricants

Clarifying alcoholic beverages

Apparatus for microbiology

Cleaning or keeping clear the surface of open water; Apparatus therefore

Kitchen sinks

Stormwater treatment

Other installations or implements for operating sewer systems (cleaning, emptying, maintenance)

Sludge tanker

Working-up Building material

Treatment of water for swimming pools

Sedimentation devices used in drilling boreholes

Separation of well effluents

Measuring volume flow, mass flow or liquid level (e.g. indicating or measuring liquid level G01F 23/00)

Investigating and analysing materials by determining their chemical or physical properties (e.g. density G01N 9/00)

Control of non-electrical variables

Special rules of classification within this group

In the absence of an indication to the contrary, classification is made for each technical feature shown in the document.

Gravity filters (with moving filtering elements B01D 33/0035)
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
Special rules of classification within this group
  • The group B01D 23/00 is no more valid for classification.

The group B01D 24/00 was introduced in March 1989. This group includes subject matter of B01D 23/00, B01D 25/06, B01D 25/10, B01D 29/0027, B01D 33/0032 and B01D 33/0054

  • Documents from the backlog of the group B01D 23/00, and the subgroups

B01D 25/06, B01D 25/10, B01D 29/0027, B01D 33/0032 and B01D 33/0054 are in the process of being revised and also systematically transferred to B01D 24/00

Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof (B01D 27/02 takes precedence)
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Treatment of water, waste water, sewage, or sludge only when no mechanical filtration is involved

Chemical or physical processes

Gas Filters

Separation of gases or vapours

With cartridges made from a mass of loose materials

Informative references
Attention is drawn to the following places, which may be of interest for search:

Gravity filters

Filters with loose, granular or fibrous filtering elements, formed by clamping together several filtering elements

Filters in which the suspended particles form the filtering medium, formed by clamping together several filtering elements

Filters with loose, granular or fibrous filtering elements with filtering elements stationary during filtration

Filters with loose, granular or fibrous filtering elements with filtering elements moving during the filtering operation (with drums)

Filters with loose, granular or fibrous filtering elements with filtering elements moving during the filtering operation (with plane surfaces)

Special rules of classification within this group
  • Documents from the backlog of the group B01D 23/00, and the subgroups

B01D 25/06, B01D 25/10, B01D 29/0027, B01D 33/0032 and B01D 33/0054 are in the process of being revised and also systematically transferred to B01D 24/00

{Filters being divided into a plurality of cells or compartments (B01D 24/004 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Arranged concentrically or coaxially

the filtering material being clamped between pervious fixed walls (B01D 24/10 , B01D 24/20 take precedence)
References relevant to classification in this group
This subgroup does not cover:

The filtering material being held in a closed container

The filtering material being held in an open container

Downward filtration, the filtering material being supported by pervious surfaces (B01D 24/18 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Combined upward and downward filtration

Downward filtration, the container having distribution or collection headers or pervious conduits (B01D 24/18 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Combined upward and downward filtration

Upward filtration (B01D 24/18 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Combined upward and downward filtration

{Special treatment of the feed stream before contacting the filtering material, e.g. cutting (B01D 35/24 , B01D 37/02 , B01D 37/03 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Providing loose granular material to scratch the filters clean

Precoating the filter medium; Addition of filter aids to the liquid being filtered

Using flocculating agents

Regenerating the filtering material in the filter (B01D 24/44 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

For discharging filter cake

{by scrapers, brushes, nozzles or the like placed on the cake-side of the stationary filtering material and only contacting the external layer (B01D 24/4631 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Counter-current flushing

{by moving the filtering element (B01D 24/4605 and B01D 24/4631 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

By scrapers, brushes, nozzles or the like placed on the cake-side of the stationary filtering material and only contacting the external layer

Counter-current flushing

{Retarding cake deposition on the filter during the filtration period, e.g. using stirrers (B01D 24/407 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Provoking a tangential stream

{in which the filtering elements are moved between filtering operations; particular measures for removing or replacing the filtering elements (B01D 24/46 , B01D 24/4807 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Regenerating the filtering material in the filter

Handling the filter cake for purposes other than regenerating

Filters formed by clamping together several filtering elements or parts of such elements (disc filters B01D 29/39)
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Edge filtering elements, i.e. using impervious surfaces.

Treatment of water, waste water, sewage, or sludge only when no mechanical filtration is involved

Chemical or physical processes

Gas Filters

Separation of gases or vapours

Disc filters

Special rules of classification within this group
{Making filtering elements (not provided for elsewhere; see also B01D 24/001 , B01D 27/005 , B01D 29/012 , B01D 29/111 , B01D 33/0093)}
References relevant to classification in this group
This subgroup does not cover:

Making filter elements

Making filter elements

Making filtering elements

Making filtering elements

Making filter elements

{Clamping devices (B01D 25/12 and subgroups take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Filter presses

with one or more movable filter bands arranged to be clamped between the press plates or between a plate and a frame during filtration, e.g. zigzag endless filter bands (B01D 25/172 , B01D 25/176 , B01D 25/19 take precedence)
References relevant to classification in this group
This subgroup does not cover:

Plate spreading means

Attaching the filter elements to the filter press plates

Clamping means for closing the filter press

Plate and frame presses (B01D 25/172 , B01D 25/176 , B01D 25/19 take precedence)
References relevant to classification in this group
This subgroup does not cover:

Plate spreading means

Attaching the filter elements to the filter press plates

Clamping means for closing the filter press

{with internal recirculation through the filtering element (B01D 37/02 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Precoating the filter medium; Addition of filter aids to the liquid being filtered

by moving,{e.g. rotating,}the filter elements{(B01D 25/172 , B01D 25/19 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Plate spreading means

Clamping means for closing the filter press

{Particular measures for replacing or isolating one or more filtering elements; Transport systems for the filtering apparatus (B01D 25/28 , B01D 25/32 , B01D 25/346 , B01D 25/36 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Leaching or washing filter cakes in the filter

Removal of filter cakes

By vibration

By centrifugal force

Cartridge filters of the throw-away type
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Treatment of water, waste water, sewage, or sludge only when no mechanical filtration is involved

Gas Filters

Separation of gases or vapours

Chemical or physical processes

Special rules of classification within this group
Other filters with filtering elements stationary during filtration, e.g. pressure or suction filters, or filtering elements therefor{(B01D 24/00 , B01D 25/00 and B01D 27/00 take precedence)}
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Filters comprising loose filtering material

Filters formed by clamping together several filtering elements or parts of such elements

Cartridge filters of the throw-away type

Treatment of water, waste water, sewage, or sludge

Chemical or physical processes

Deep fat fryers with means for filtering the frying liquid

Filters for extrusion molding

Filters or strainers for coffee or tea makers

Paint filters

Filter for medical purposes, body liquids

Filters for dental appliances

Filters used in drilling boreholes

Filters for molten metals

Filters for washing or rinsing machines for crockery or tableware

Filters for refrigeration machines , plants or systems

Ink filters for printers

Membranes

Separating solids from solids by sieving, screening

Gas Filters

Filters in sewerage structures

Separation of gases or vapours

Filters for washing or rinsing machines for crockery or tableware

Filters for laboratory use

Filters for washing machines (laundering)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Filters with filtering elements stationary during filtration (The documents from the backlog of the subgroups of group B01D 29/0002 are in the process of being systematically transferred to the other subgroups of group B01D 29/00)

Filters for machine tools

Filters for swimming pools

Filters for aquaria

Filters for liquid fuel used in combustion engines

Filters for oil used for lubricating machines

Special rules of classification within this group
{with curved filtering elements (B01D 29/072 , B01D 29/073 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Ring shaped

With wound filtering sheets

with filtering bands, e.g. movable between filtering operations{(B01D 25/121 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

With bandshaped filtering elements intermittently entrained between the press plates, the lateral sides of the elements being clamped between two successive plates or between a plate and a successive frame during the filtration period.

{arranged for inward flow filtration (B01D 29/15 , B01D 29/33 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Arranged for inward filtration

Arranged for inward filtration

{arranged for outward flow filtration (B01D 29/23 , B01D 29/35 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Arranged for outward filtration

Arranged for outward filtration

with multiple filtering elements, characterised by their mutual disposition (B01D 29/39 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

With hollow discs side by side on, or around , one or more tubes

Handling the filter cake in the filter for purposes other than for regenerating (B01D 29/94 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

For discharging the filter cake

{using screws (B01D 29/6476 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

With a rotary movement with respect to the filtering element

Retarding cake deposition on the filter during the filtration period, e.g. using stirrers{(B01D 29/908 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Provoking a tangential stream

{with internal recirculation through the filtering element (B01D 37/02 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Precoating the filter medium ; addition of filter aids to the liquid being filtered

{directing the mixture to be filtered on the filtering element in a manner to clean the filter continuously (B01D 29/115 , B01D 29/118 , B01D 29/17 , B01D 29/25 , B01D 29/336 , B01D 29/356 , B01D 29/902 , B01D 29/908 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Open-ended, the arrival of the mixture to be filtered and the discharge of the concentrated mixture are situated on both opposite sides of the filtering element

Open-ended

Open-ended, the arrival of the mixture to be filtered and the discharge of the concentrated mixture are situated on both opposite sides of the filtering element

Open-ended, the arrival of the mixture to be filtered and the discharge of the concentrated mixture are situated on both opposite sides of the filtering element

Open-ended, the arrival of the mixture to be filtered and the discharge of the concentrated mixture are situated on both opposite sides of the filtering element

Open-ended, the arrival of the mixture to be filtered and the discharge of the concentrated mixture are situated on both opposite sides of the filtering element

Containing liquid displacement elements or cores

Provoking a tangential stream

{Special treatment of the feed stream before contacting the filtering element, e.g. cutting (B01D 35/24 , B01D 37/02 , B01D 37/03 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Providing loose granular material to scratch the filters clean

Precoating the filter medium; Addition of filter aids to the liquid being filtered

Using flocculating agents

in which the filtering elements are moved between filtering operations; Particular measures for removing or replacing the filtering elements; Transport systems for filters (B01D 29/09 , B01D 29/70 take precedence)
References relevant to classification in this group
This subgroup does not cover:

With filtering bands, e.g. movable between filtering operations

By forces created by movement of the filter element

Filters with filtering elements which move during the filtering operation (filters comprising loose filtering material moving or fluidised during filtration B01D 24/28 to B01D 24/36 ; centrifuges B04B)
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Treatment of water, waste water, sewage, or sludge

Chemical or physical processes

Deep fat fryers with means for filtering the frying liquid

Centrifuges

Filters for washing or rinsing machines for crockery or tableware

Filters for washing machines (Laundering)

Filters for extrusion molding

Paint filters

Filter for medical purposes, body liquids

Filters for dental appliances

Filters used in drilling boreholes

Filters for molten metals

Filters for washing or rinsing machines for crockery or tableware

Filters for refrigeration machines , plants or systems

Membranes

Filters for laboratory use

Gas Filters

Separation of gases or vapours

Filters comprising loose filtering material moving or fluidised during filtration

Informative references
Attention is drawn to the following places, which may be of interest for search:

Filters with filtering elements stationary during filtration (The documents from the backlog of the subgroups of group B01D 33/0003 are in the process of being systematically transferred to the other subgroups of group B01D 33/00)

Filters for swimming pools

Filters for aquaria

Filters for machine tools

Separating solids from solids by sieving, screening

Purification of the paper pulp suspension by mechanical means; Apparatus therefor.

Filters with tipping buckets or trays

Special rules of classification within this group
with translationally moving filtering elements, e.g. pistons (B01D 33/04 to B01D 33/327 take precedence)
References relevant to classification in this group
This subgroup does not cover:

with filtering bands or the likes supported on cylinders which are impervious for filtering

Tipping buckets, trays or like sections

with rotary cylindrical filtering surfaces, e.g. hollow drums (B01D 33/044 takes precedence; { rotating drums for paper-making D21B})
References relevant to classification in this group
This subgroup does not cover:

With filtering bands or the like supported on cylinders which are pervious for filtering

the movement of the filter elements being a combination of movements (B01D 33/19 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

The table surface being divided in successively tilted sectors or cells

with multiple filtering elements characterised by their mutual disposition ({B01D 33/042} , B01D 33/21 take precedence)
References relevant to classification in this group
This subgroup does not cover:

Whereby the filtration and squeezing-out take place between at least two filtering bands

With hollow filtering discs transversely mounted on a hollow rotary shaft

by scrapers, brushes {nozzles}or the like acting on the cake-side of the filtering element{(B01D 33/503 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

The backwash arms, shoes acting on the cake side

Handling the filter cake in the filter for purposes other than for regenerating (B01D 33/76 takes precedence){the filter cake remaining on the filtering element}
References relevant to classification in this group
This subgroup does not cover:

For discharging the filter cake

having feed or discharge devices (B01D 33/82 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Means for pressure distribution

{Special treatment of the feed stream before contacting the filtering element, e.g. cutting (B01D 35/24 , B01D 37/02 , B01D 37/03 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Providing loose granular material to scratch the filters clean

Precoating the filter medium; Addition of filter aids to the liquid being filtered

Using flocculating agents

{in which the filtering elements are moved between filtering operations (B01D 33/52 takes precedence); Particular measures for removing or replacing the filtering elements; Transport systems for filters}
References relevant to classification in this group
This subgroup does not cover:

By forces created by movement of the filter element

Other filtering devices; Auxiliary devices for filtration; Filter housing constructions
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Treatment of water, waste water, sewage, or sludge only when no mechanical filtration is involved

Chemical or physical processes

Filtering elements installed in valves

Deep fat fryers with means for filtering the frying liquid

Filters for extrusion molding

Filters or strainers for coffee or tea makers

Paint filters

Filter for medical purposes, body liquids

Filters for dental appliances

Filters used in drilling boreholes

Filters for molten metals

Filters for washing or rinsing machines for crockery or tableware

Filters for refrigeration machines , plants or systems

Ink filters for printers

Membranes

Separating solids from solids by sieving, screening

Gas Filters

Filters in sewerage structures

Filters for washing or rinsing machines for crockery or tableware

Separation of gases or vapours

Filters for laboratory use

Filters for washing machines (laundering)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Filters for aquaria

Magnetic separation of solid materials from liquids

Filters for liquid fuel with pumps

Filters for liquid fuel with heating means

Special rules of classification within this group
  • B01D 35/08 is no longer used for the classification of new documents, documents are classified in B01D 33/327
  • The combination classes of the type B01D 35/147+B01D35/30 are no longer used from October 1, 2011 onwards. Documents are classified as Combination-sets(C-set), e.g. (B01D 35/147, B01D 35/30).
Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks,(B01D 35/05 takes precedence; { water pipe system filters E03B 3/18 , E03B 7/07 ; dirt catchers in sewers E03F; filters or strainers for pipe-lines in general B08B, E03F; object or dirt catching devices in sinks or the like E03C 1/26 ; suction strainers or filters for pumps F04B 53/005 , F04D 29/70})
References relevant to classification in this group
This subgroup does not cover:

Floating filters

rigidly mounted in or on tanks or reservoirs (B01D 35/04 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Plug, tap or cock filters

Directing the mixture to be filtered on to the filters in a manner to clean the filters{(B01D 29/904 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Directing the mixture to be filtered on the filtering element in a manner to clean the filter continuously

{Constructions of two or more housings (B01D 35/12 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Devices for taking out of action one or more units of multi-unit filters

open-topped (B01D 35/31 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Including arrangements for environmental protection

Filter circuits or combinations of filters with other separating devices
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Treatment of water, waste water, sewage, or sludge

Chemical or physical processes

Deep fat fryers with means for filtering the frying liquid

Filters for extrusion molding

Filters or strainers for coffee or tea makers

Paint filters

Filter for medical purposes, body liquids

Filters for dental appliances

Filters used in drilling boreholes

Filters for molten metals

Filters for washing or rinsing machines for crockery or tableware

Filters for refrigeration machines , plants or systems

Ink filters for printers

Membranes

Separating solids from solids by sieving, screening

Gas Filters

Separation of gases or vapours

Filters for sewerage structures

Filters for washing or rinsing machines for crockery or tableware

Filters for washing machines (laundering)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Liquid fuel filters with water separation means

Special rules of classification within this group
{Filters in combination with devices for the removal of liquids (B01D 35/185 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Comprising a vapourizing unit

Combinations of filters of different kinds (B01D 29/50 , B01D 33/35 take precedence)
References relevant to classification in this group
This subgroup does not cover:

With multiple filtering elements, characterized by their mutual disposition

With multiple filtering elements, characterized by their mutual disposition

Processes of filtration (processes specially adapted for filtering gases B01D 46/00)
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Treatment of water, waste water, sewage, or sludge

Chemical or physical processes

Deep fat fryers with means for filtering the frying liquid

Filters for extrusion molding

Filters or strainers for coffee or tea makers

Paint filters

Filter for medical purposes, body liquids

Filters for dental use

Filters used in drilling boreholes

Filters for molten metals

Filters for washing or rinsing machines for crockery or tableware

Filters for refrigeration machines , plants or systems

Ink filters for printers

Membranes

Separating solids from solids by sieving, screening

Gas Filters

Separation of gases or vapours

Filters for sewerage structures

Filters for washing or rinsing machines for crockery or tableware

Filters for washing machines (laundering)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Treatment of oil (motor oil systems)

Special rules of classification within this group
Filtering material for liquid or gaseous fluids
Definition statement
This group covers:

Mainly materials for mechanical filtration, however materials with additives e.g. adsorbents are also included. Also composite filtering materials with combined activity (mechanical filtration, adsorption, antimicrobial action etc. are also under the present group.

Special rules of classification within this subclass
  • The subgroups B01D 39/1684 is no longer used for classification as from December 1, 2011

The backlog of this group is being continuously reclassified to B01D 39/16 B01D 2239/0695.

The subgroup B01D 39/2096 is no longer used for classification as from December 1, 2011.

The backlog of this group is being continuously reclassified to B01D 39/20 and B01D 2239/0695.

Filter cloth, i.e. woven, knitted or interlaced material (metallic B01D 39/10)
References relevant to classification in this group
This subgroup does not cover:

Metallic material

Special rules of classification within this subgroup
Other self-supporting filtering material;{Other filtering material(non-woven fabrics in general D04H 3/00)}
Definition statement
This subgroup covers:

This subgroup covers non-woven, foamy, porous films and bonded particulate filter materials.

References relevant to classification in this group
This subgroup does not cover:

Filter cloths

Metallic screens, expanded films

Loose filtering material

Informative references
Attention is drawn to the following places, which may be of interest for search:

Non-woven fabrics in general

{the material being fibrous (B01D 39/18 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Fibrous cellulosic material

the material being cellulose or derivatives thereof ({cork or peat B01D 39/1646} ; making filter paper D21F 11/14)
Informative references
Attention is drawn to the following places, which may be of interest for search:

Cork or peat particulate filters

Making filter paper

of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires (porous ceramic material{C04B 38/00} ; sintering metals C22C 1/04 ; { making porous sintered metal bodies B22F 3/10 , honeycomb filters B01D 46/2418 , materials used for filtering exhaust gases of an internal combustion engine F01N/022, ceramic honeycomb structures C04B 38/0006})
Informative references
Attention is drawn to the following places, which may be of interest for search:

Making porous sintered bodies

Honeycomb filters

Honeycomb filters used for filtering exhaust gases of an internal combustion engine

Ceramic honeycomb structure

{Carbonaceous material (solid sorbent compositions comprising free carbon B01J 20/20)}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Solid sorbent compositions comprising free carbon

Special rules of classification within this subgroup
Regeneration of the filtering material or filter elements outside the filter for liquid or gaseous fluids
References relevant to classification in this group
This group does not cover:

Regeneration of liquid filters under:

Regeneration of gas filters under:

Separating particles from liquids, or liquids from solids, otherwise than by sedimentation or filtration (flotation processes B03D 1/00 ; drying solid materials or objects F26B)
References relevant to classification in this group
This group does not cover:

Liquid filtration

Gas filtration

Sedimentation or flotation

Separation of immiscible liquids

Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
Definition statement
This group covers:
  • Separators used for filtering particles out of a gas or vapour.
  • Only mechanical separation is taking place, no reaction, no absorption or adsorption is involved
Informative references
Attention is drawn to the following places, which may be of interest for search:

Centrifuges

Cyclones

by utilising inertia (B01D 45/12 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Separating dispersed particles by centrifugal forces

Filters {i.e. particle separators}or filtering processes specially modified for separating dispersed particles from gases or vapours (filtering elements B01D 23/00 to B01D 35/00 ; filtering material B01D 39/00 ; their regeneration outside the filters B01D 41/00)
Definition statement
This group covers:
  • Filters used for filtering particles out of a gas.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Chemical or physical processes

Sterilisation of air

Electrostatic filters

Magnetic filters

Separating particles using centrifugal forces or inertia

Cyclones

Centrifuges

Membranes

Separating solids from solids by sieving, screening

Liquid filters

Separation of gases or vapours

Filters for laboratory use

Filter materials

Ceramic honeycomb structures per se

Informative references
Attention is drawn to the following places, which may be of interest for search:

Air conditioning systems comprising filters

Intake systems for internal combustion engines

Air conditioning systems for vehicles including filters

Exhaust filters for internal combustion engines

Suction cleaners having filters

A47L8/10

Filters for kitchen

Sterilization of air by filtration

{Mounting of filtering elements within casings, housings or frames (B01D 46/2422 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Mounting of honeycomb bodies

{provoking a tangential stream (B01D 46/0045 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Flow guiding by feed devices using vanes

{with filtering elements moving during filtering operation (B01D 46/22 , B01D 46/32 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Filters having travelling belts

Loose filtering material moving during filtration

{Regenerating the filter material in the filter (B01D 46/04 , B01D 46/48 take precedence)}
References relevant to classification in this group
This subgroup does not cover:

Cleaning filters of flexible material

Removing dust from a filter housing

Cleaning filters outside the filter housing

{using wound sheets (B01D 46/527 takes precedence)}
References relevant to classification in this group
This subgroup does not cover:

Particle separators using folded material comprising flutes in wound arrangement

Combinations of devices for separating particles from gases or vapours
Definition statement
This group covers:
  • Separators used for filtering particles out of a gas or vapour.
  • Only mechanical separation or filtration perhaps in combination with a liquid as separating agent is taking place, no reaction, no absorption or adsorption is involved
Auxiliary pre-treatment of gases or vapours to be cleaned (preventing dust fires A62C; pretreatment specially adapted for magnetic or electrostatic separation B03C)
Informative references
Attention is drawn to the following places, which may be of interest for search:

Preventing dust fires

Pretreatment specially adapted for magnetic or electrostatic separation

Special rules of classification within this group

These groups are, if possible, to be combined with groups from B01D 53/00 or symbols from B01D 53/00, B01D 2251/00, B01D 2256/00, B01D 2257/00 and B01D 2259/00 (multiple classification)

Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols,(recovery of volatile solvents by condensation B01D 5/00 ; sublimation B01D 7/00 ; cold traps, cold baffles B01D 8/00 ; working-up undefined gaseous mixtures obtained by cracking hydrocarbon oils C10G 70/00 ; cleaning coal gas C10K ; working-up of natural gas, or synthetic natural gas, C10L 3/10 ; separation of difficult-to-condense gases or air by liquefaction F25J ; for investigating materials G01N 30/00)
Definition statement
This group covers:

Catalytic treatment of gases in B01D 53/00 is only for waste gases, i.e. catalytic treatment or synthesis of other gases such as commercially relevant gases (e.g. synthesis or natural gas) is not classified in B01D 53/00).

Relationship between large subject matter areas

Cleaning coal gas: C10K

Separation of difficult-to-condense gases or air by liquefaction: F25J

References relevant to classification in this group
This group does not cover:

Catalytic treatment of exhaust gases from engine exhaust gases (a waste gas)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Recovery of volatile solvents by condensation

Sublimation

Cold traps

Working-up undefined gaseous mixtures obtained by cracking hydrocarbon oils

Working-up of natural gas, or synthetic natural gas

Drying air in air conditioning systems

Investigating materials

Special rules of classification within this group

B01D 53/00 to B01D 53/326 are generally applied for all gases except for waste gases. Waste gases are mainly dealt with in B01D 53/34 to B01D 53/96. In cases where no appropriate treatment concept can be found for waste gases, the groups

{by condensation}
Relationship between large subject matter areas

Condensation of vapours; recovering volatile solvents by condensation

Separation of difficult-to-condense gases or air by liquefaction

References relevant to classification in this group
This subgroup does not cover:

Cryogenic condensation only for carbon dioxide (CO 2)

Condensation of water vapour

Solidifying carbon dioxide

Other gas mixtures

{by irradiation}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Disinfection, sterilisation or deodorisation of air

Special rules of classification within this group

This group (and corresponding additional information symbols) is often given for waste gases, too.

Symbols B01D 2259/80 to B01D 2259/816 are to applied where possible.

Concepts applying photo-catalytic treatment should be given the symbol B01D 2255/804.

by adsorption, e.g. preparative gas chromatography{(solid sorbent compositions B01J 20/00 , preparation of inorganic compounds or elements C01)}
Definition statement
This subgroup covers:

Only specific solid adsorbent materials, i.e. not for documents covering general aspects of adsorption.

Relationship between large subject matter areas

Solid sorbent compositions.

Preparation of inorganic compounds or elements

C01

Special rules of classification within this group

Symbols B01D 2253/00 and B01D 2257/00 are to be applied where appropriate.

Documents from other technical fields in which adsorption is mentioned as one of many possible applications or a minor aspect. For such cases, B01D 53/02 should be given.

with stationary adsorbents{(B01D 53/025 takes precedence)}
Definition statement
This subgroup covers:

General adsorption process aspects.

This group is often used for (general) regeneration aspects and new combinations of known adsorbents for specific gases.

References relevant to classification in this group
This subgroup does not cover:

Takes precedence

Controlling processes and pressure & temperature swing adsorption processes

Documents from other technical fields in which adsorption is mentioned as one of many possible applications or a minor aspect

Special rules of classification within this group

Symbols to be applied where possible: B01D 2253/00; B01D 2256/00; B01D 2257/00; B01D 2259/40083 to B01D 2259/4583.

{Constructional details of adsorbing systems}
Definition statement
This subgroup covers:

Apparatus (mechanical) related concepts (as opposed to process related inventions classified in B01D 53/04).

Special rules of classification within this group

Symbols to be applied where possible: B01D 2253/00; B01D 2256/00; B01D 2257/00; B01D 2259/45 to B01D 2259/4583.

{Beds with radial gas flow}
Definition statement
This subgroup covers:

Concepts with an annular bed in form of a hollow cylinder.

{Cooling or heating systems}
Definition statement
This subgroup covers:

Mainly regeneration systems.

Special rules of classification within this group

Very relevant symbols to be applied where possible: B01D 2259/40083 to B01D 2259/40098.

{Means for feeding or distributing gases}
Definition statement
This subgroup covers:

Concepts focussed on ducts, manifolds, flow dividers, pumps, valves, etc.

Special rules of classification within this group

Symbols for (specific) valves: B01D 2259/40003 and B01D 2259/40005.

{Controlling adsorption (controlling temperature swing adsorption B01D 53/0462 , controlling pressure swing adsorption B01D 53/047)}
References relevant to classification in this group
This subgroup does not cover:

Documents relating to pressure swing adsorption (PSA)

Documents relating to temperature swing adsorption (TSA)

Pressure swing adsorption
Definition statement
This subgroup covers:

PSA processes characterised by a sequences of cycle steps

Special rules of classification within this group

Documents from other technical fields in which PSA is mentioned as one of many possible applications or a minor aspect. For such cases, B01D 53/047 should be given.

{Rapid pressure swing adsorption}
Definition statement
This subgroup covers:

RPSA processes characterised by a sequences of cycle steps

Special rules of classification within this group

Documents from other technical fields in which RPSA is mentioned as one of many possible applications or a minor aspect. For such cases, B01D 53/0473 should be given.

{Vacuum pressure swing adsorption}
Definition statement
This subgroup covers:

VPSA processes characterised by a sequences of cycle steps.

Special rules of classification within this group

Documents from other technical fields in which VPSA is mentioned as one of many possible applications or a minor aspect. For such cases, B01D 53/0476 should be given.

with storage or buffer vessel
Special rules of classification within this group
with moving adsorbents, e.g. rotating beds{(B01D 53/025 takes precedence)}
Definition statement
This subgroup covers:

Moving (e.g. rotating or oscillating) adsorbent structures or units, e.g. rotating beds.

References relevant to classification in this group
This subgroup does not cover:

Separation of gases or vapours with wetted absorbents

Informative references
Attention is drawn to the following places, which may be of interest for search:

Drying air in air conditioning systems

Special rules of classification within this group

Systems for drying air by solid bed adsorption (classified in B01D 53/261) are also classified in this group where possible.

according to the "moving bed" method
Definition statement
This subgroup covers:

Concepts where adsorbent particles travel (mainly by gravity) through a reactor and are often, after regeneration, reintroduced.

Glossary of terms
In this subgroup, the following terms (or expressions) are used with the meaning indicated:

In the patent documents the following expressions/words "Fliessbett, Wanderbett" (German) ,"fluidized bed" and "moving bed" are often used as synonyms.

with dispersed adsorbents
Definition statement
This subgroup covers:

Concepts where (loose) adsorbent particles are dispersed into a gas stream for a short residence (contact) time.

References relevant to classification in this group
This subgroup does not cover:

Concepts with loose particles being held for a longer residence time in a fluidized state

Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes

according to the "fluidised technique"
Definition statement
This subgroup covers:

Concepts with loose particles being held for a longer residence time in a fluidized state.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes

by absorption
Definition statement
This subgroup covers:

Concepts using liquid physical and chemical solvents

Informative references
Attention is drawn to the following places, which may be of interest for search:

Treatment of gaseous fuels, natural gas or synthetic natural gas

Special rules of classification within this group

Symbols to be allocated where appropriate B01D 2252/00

Documents from other technical fields in which absorption is mentioned as one of many possible applications or a minor aspect. For such cases, B01D 53/14 should be given.

{Selection of liquid materials for use as absorbents}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Treatment of gaseous fuels, natural gas or synthetic natural gas

Acyclic or carboxylic compounds

Special rules of classification within this group

Symbols B01D 2252/00 are to be used in combination with this group.

Absorbing units; Liquid distributors therefor (B01D 3/16 , B01D 3/26 , B01D 3/30 take precedence; packing elements B01J 19/30 , B01J 19/32)
Definition statement
This subgroup covers:

Apparatus (mechanical) aspects of absorption columns or units.

References relevant to classification in this group
This subgroup does not cover:

Fractionating columns

Informative references
Attention is drawn to the following places, which may be of interest for search:

Packing elements

by diffusion (manufacturing semi-permeable membranes B01D 67/00 ; form, structure or properties of semi-permeable membranes B01D 69/00 ; material for semi-permeable membranes B01D 71/00)
Definition statement
This subgroup covers:

The groups B01D 53/22 to B01D 53/229 cover gas separation concepts using membranes.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Apparatus and accessoirs in general for separation processes using semipermeable membranes

Manufacturing semipermeable membranes

Form, structure or properties of semi-permeable membranes

Material for semipermeable membranes

by centrifugal force (centrifuges B04B ; cyclones B04C)
References relevant to classification in this group
This subgroup does not cover:

Centrifugal separation of particles or aerosols from a gas stream

Informative references
Attention is drawn to the following places, which may be of interest for search:

Separating dispersed particles or aerosols from gases or vapours

Centrifuges

Apparatus using free vortex flow, e.g. cyclones

Drying gases or vapours
Definition statement
This subgroup covers:

Concepts for removing water vapour from a gas.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Dehumidification in air conditioning systems

{by adsorption}
Definition statement
This subgroup covers:

Use of solid sorbents as drying agents.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Dehumidification in air conditioning systems

Special rules of classification within this group

For apparatus related features, documents are often classified in B01D 53/0407 to B01D 53/0446, B01D 53/06, B01D 53/0407 to B01D 53/0446, B01D 53/06

{by absorption}
Definition statement
This subgroup covers:

Gas drying concepts using a liquid drying agent (solvent).

Informative references
Attention is drawn to the following places, which may be of interest for search:

Dehumidification in air conditioning systems

Special rules of classification within this group

Symbols B01D 2252/00 are to be used where possible.

{by refrigeration (condensation)}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Collecting potable water from air

Condensation of vapours

Steam or vapour condensers

Heat exchange and heat transfer apparatus

{by diffusion}
Definition statement
This subgroup covers:

Gas drying concepts using membranes.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Apparatus and accessoirs in general for separation processes using semipermeable membranes

Manufacturing semipermeable membranes

Form, structure or properties of semi-permeable membranes

Material for semipermeable membranes

Separation of gases by diffusion

Selection of materials for use as drying agents
Special rules of classification within this group
Controlling by gas-analysis apparatus (regulating non electrical variables in general G05D)
Informative references
Attention is drawn to the following places, which may be of interest for search:

Investigating or analysing materials by determining their chemical or physical properties

Controlling or regulating systems or variables

by electrical effects other than those provided for in group B01D 61/00
Definition statement
This subgroup covers:

Concepts using electric discharge or corona discharge, e.g. a plasma treatment.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Separation by high-voltage electrical fields

Special rules of classification within this group

All documents using an electrical plasma are classified her. The corresponding symbol for those documents is B01D 2259/818.

Symbols B01D 2259/80 to B01D 2259/818 are to be applied where appropriate.

{by electrostatic effects or by high-voltage electric fields}
Definition statement
This subgroup covers:

Concepts using electric fields where no discharge takes place.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Separation by high-voltage electrical fields

Special rules of classification within this group

Symbols B01D 2259/80 to B01D 2259/818 are to be applied where appropriate.

{in electrochemical cells}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Electrolytic or electrophoretic processes for the production of (.e.g. gaseous) compounds

Chemical or biological purification of waste gases
Special rules of classification within this group

The treatment of waste gases is divided into chemical concepts (B01D 53/34 to B01D 53/83), biological concepts (B01D 53/84, B01D 53/85) and catalytic concepts (B01D 53/86 to B01D 53/90).

Exhaust (waste) gases from internal combustion engines are classified in B01D 53/92 (non catalytic) and in B01D 53/94 to B01D 53/9495 (catalytic).

{Heat recovery}
Special rules of classification within this group

Symbols B01D 2259/65 to B01D 2259/657 are to be applied where appropriate.

{Controlling the process}
Definition statement
This subgroup covers:

Controlling concepts for chemical and biological waste gas treatments.

References relevant to classification in this group
This subgroup does not cover:

Controlling catalytic processes

Controlling catalytic processes involving engine exhaust gases

Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling or regulating systems or variables

Special rules of classification within this group

This group should, if possible, be allocated in combination with another group and/or additional information symbol specifying the chemical or biological waste gas treatment concept.

Removing components of undefined structure
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes

Special rules of classification within this group

This group should, if sensible, be allocated in combination with another group selected from B01D 53/74 to B01D 53/83 and/or symbol selected notably from B01D 2258/00.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators

Acidic components (B01D 53/44 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Organic components

Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes

Special rules of classification within this group

This group should, if sensible, be allocated in combination with another group selected from B01D 53/74 to B01D 53/83 and/or symbols selected notably from B01D 2258/00.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators

Basic components (B01D 53/44 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Organic components

Special rules of classification within this group

This group should, if sensible, be allocated in combination with another group selected from B01D 53/74 to B01D 53/83 and/or symbols selected notably from B01D 2258/00.

Organic components
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Special rules of classification within this group

This group should, if sensible, be allocated in combination with another group selected from B01D 53/74 to B01D 53/83 and/or symbol selected notably from B01D 2258/00.

Removing components of defined structure
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Sulfur compounds
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

{containing only one sulfur compound other than sulfur oxides or hydrogen sulfide}
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Sulfur oxides (B01D 53/60 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Removing sulfur dioxide or sulfur trioxide from gases other than waste gases by absorption with solvents

Corresponding group for catalytic treatments

Simultaneously removing sulphur oxides and nitrogen oxides

Informative references
Attention is drawn to the following places, which may be of interest for search:

Production of sulfur from gaseous compounds including gaseous sulfides

{by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound}
References relevant to classification in this group
This subgroup does not cover:

Removing sulfur dioxide or sulfur trioxide from gases other than waste gases by absorption with solvents

Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes using washing liquids

{characterised by a specific solution or suspension}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Removing sulfur dioxide or sulfur trioxide by absorption with solvents

Arrangement or devices for treating smokes or fumes using washing liquids

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol selected notably from B01D 2251/00.

{characterised by a specific device}
Definition statement
This subgroup covers:

Constructional (mechanical) concepts related to desulfurization.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Separating dispersed particles from gases, air or vapours

Absorbing units, liquid distributors therefore

Spraying apparatus, nozzles.

Special rules of classification within this group

Examples for concepts in this group are scrubbers, sprayers, contactors

{in a spray drying process}
Definition statement
This subgroup covers:

Inter alia concepts involving semi-solid reagents such as slurries.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes using washing liquids

{by treating the gases with other liquids}
References relevant to classification in this group
This subgroup does not cover:

Removing sulfur dioxide or sulfur trioxide from gases other than waste gases by absorption with solvents

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbols selected notably from B01D 2251/00 and from B01D 2252/00

{by treating the gases with solids}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Solid gas separation processes in general

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbols selected notably from B01D 2251/00 and B01D 2253/00.

Hydrogen sulfide
References relevant to classification in this group
This subgroup does not cover:

Removing hydrogen sulfide from gases other than waste gases by absorption with solvents

Corresponding group for catalytic treatments

Informative references
Attention is drawn to the following places, which may be of interest for search:

Production of sulfur from gaseous compounds including gaseous sulfides

Special rules of classification within this group

Treatment concepts with regenerable solvents are also classified in B01D 53/1468 (even waste gases).

This group should, if sensible, be allocated in combination with symbol selected notably from B01D 2251/00.

{Mixtures of hydrogen sulfide and sulfur oxides}
References relevant to classification in this group
This subgroup does not cover:

Corresponding group for catalytic treatments: B01D 53/8615

Informative references
Attention is drawn to the following places, which may be of interest for search:

Production of sulfur from gaseous compounds including gaseous sulfides

Arrangement or devices for treating smokes or fumes liquids

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol selected notably from B01D 2251/00.

{Mixtures of hydrogen sulfide and carbon dioxide}
References relevant to classification in this group
This subgroup does not cover:

Removing hydrogen sulfide and carbon dioxide from gases other than waste gases by absorption with solvents

Corresponding group for catalytic treatments

Informative references
Attention is drawn to the following places, which may be of interest for search:

Production of sulfur from gaseous compounds including gaseous sulfides

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbols selected notably from B01D 2251/00 to B01D 2251/90

Nitrogen compounds
References relevant to classification in this group
This subgroup does not cover:

Corresponding group for catalytic treatments

Nitrogen oxides (B01D 53/60 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Corresponding group for catalytic treatments

Simultaneously removing sulphur oxides and nitrogen oxides

{by treating the gases with solids}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Solid gas separation processes in general

Ammonia
References relevant to classification in this group
This subgroup does not cover:

Corresponding group for catalytic treatments

Informative references
Attention is drawn to the following places, which may be of interest for search:

Separation of ammonia by absorption or condensation

Separation of ammonia from gases or vapours

Simultaneously removing sulfur oxides and nitrogen oxides
References relevant to classification in this group
This subgroup does not cover:

Corresponding group for catalytic treatments

Informative references
Attention is drawn to the following places, which may be of interest for search:

General processes for purification of waste gases

Arrangement or devices for treating smokes or fumes liquids

Carbon oxides
References relevant to classification in this group
This subgroup does not cover:

Catalytic removal of carbon monoxide:

Informative references
Attention is drawn to the following places, which may be of interest for search:

Solidifying carbon dioxide

Arrangement or devices for treating smokes or fumes liquids

Separation of carbon dioxide by liquefaction or solidification

Special rules of classification within this group

Treatment concepts with regenerable solvents are also classified in B01D 53/1475 (even for waste gases).

This group should, if sensible, be allocated in combination with symbol selected notably from B01D 2251/00, B01D 2252/00 and B01D 2258/00.

Frequent examples are concepts resulting in carbonate salt precipitation.

Carbon monoxide is also classified here. This is specified by symbol B01D 2257/502.

Note that carbon dioxide in a mixture with hydrogen sulfide is (also) classified in B01D 53/526.

Heavy metals or compounds thereof, e.g. mercury
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Special rules of classification within this group

Mercury is to be specified by B01D 2257/602.

Ozone
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Halogens or halogen compounds
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Informative references
Attention is drawn to the following places, which may be of interest for search:

Exhaust treatment in chemical vapour deposition processes

Special rules of classification within this group

Halogens to be removed can further be specified in B01D 2257/00.

{by treating the gases with solids}
Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbols selected notably from B01D 2251/00 and B01D 2253/00.

Organic halogen compounds
References relevant to classification in this group
This subgroup does not cover:

Catalytic treatments

Organic compounds not provided for in groups B01D 53/48 to B01D 53/70 , e.g. hydrocarbons
Special rules of classification within this group

This group should, if sensible, be allocated in combination with another group or symbol specifying the component to be removed and/or the treatment concept.

After-treatment of removed components
Special rules of classification within this group

This group should, if sensible, be allocated in combination with another group or symbol specifying the component to be removed and/or the treatment concept.

General processes for purification of waste gases; Apparatus or devices specially adapted therefor (B01D 53/92 takes precedence)
References relevant to classification in this group
This subgroup does not cover:

Chemical or biological purification of engine exhaust gases

Special rules of classification within this group

This group should, if sensible, be allocated in combination with another group or symbol specifying the component to be removed and/or the treatment concept.

Multi-step processes
Definition statement
This subgroup covers:

Processes comprising a sequence of different treatment steps. The individual steps as such do not represent the inventive concept.

References relevant to classification in this group
This subgroup does not cover:

A catalytic treatment with more than one catalytic step

Special rules of classification within this group

Sequence of steps may comprise a (one single) catalytic step.

This group should, if sensible, be allocated in combination with another group or symbol specifying the component to be removed and/or the treatment concept (e.g. B01D 53/00).

Liquid phase processes
Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes using washing liquids

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the component to be removed and/or the reactants used.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators.

with gas-liquid contact
Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes using washing liquids

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the component to be removed and/or the reactants used.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators.

Injecting reactants
Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes using washing liquids

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the component to be removed and/or the reactants used B01D 2251/00 and B01D 2252/00.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators.

Semi-solid phase processes, i.e. by using slurries
Informative references
Attention is drawn to the following places, which may be of interest for search:

Arrangement or devices for treating smokes or fumes using washing liquids

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbols specifying the component to be removed or the reactants used B01D 2251/00, B01D 2253/00, B01D 2252/00,B01D 2257/00.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators.

Solid phase processes
Relationship between large subject matter areas

Arrangement or devices for treating smokes or fumes

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the component to be removed or the reactants used B01D 2251/00, B01D 2253/00, B01D 2252/00, B01D 2257/00.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators.

with stationary reactants
Relationship between large subject matter areas

Arrangement or devices for treating smokes or fumes

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the component to be removed or the reactants used B01D 2251/00, B01D 2253/00, B01D 2252/00, B01D 2257/00.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators.

with moving reactants
Relationship between large subject matter areas

Arrangement or devices for treating smokes or fumes

Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the component to be removed and/or the reactants used B01D 2251/00, B01D 2253/00, B01D 2252/00, B01D 2257/00.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators

Biological processes
Definition statement
This subgroup covers:

All biological concepts except those using solid bed reactors.

References relevant to classification in this group
This subgroup does not cover:

Concepts with solid bed reactor

Special rules of classification within this group

symbol for specific microorganisms B01D 2251/95; symbol for bio-catalytic aspects (enzymes) B01D 2255/804.

with gas-solid contact
Definition statement
This subgroup covers:

Concepts with solid bed reactor.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Solid bed reactors for water treatment

Special rules of classification within this group

Symbol for specific microorganisms B01D 2251/95; Symbol for bio-catalytic aspects (enzymes) B01D 2255/804.

Catalytic processes
References relevant to classification in this group
This subgroup does not cover:

Catalytic concepts for engine exhaust gases

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

All groups B01D 53/86 to B01D 53/90 should, if sensible, be allocated in combination with symbols specifying the catalytic substances used B01D 2255/00.

Concepts applying photo-catalytic treatment should be given the symbol B01D 2255/804.

{Sulfur oxides}
References relevant to classification in this group
This subgroup does not cover:

Simultaneously removing sulfur oxides and nitrogen oxides: B01D 53/8637.

Removing sulfur oxides and hydrogen sulfide: B01D 53/8603.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Production of sulfur from gaseous compounds including gaseous sulfides.

{Hydrogen sulfide}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Production of sulfur from gaseous compounds including gaseous sulfides.

{Mixtures of hydrogen sulfide and sulfur oxides}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Production of sulfur from gaseous compounds including gaseous sulfides.

{Mixtures of hydrogen sulfide and carbon dioxides}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Production of sulfur from gaseous compounds including gaseous sulfides.

{Nitrogen oxides}
Definition statement
This subgroup covers:

Process related concepts (e.g. controlling) with known catalyst compositions.

References relevant to classification in this group
This subgroup does not cover:

Simultaneously removing sulfur oxides and nitrogen oxides

Special rules of classification within this group

This group can be combined with B01D 53/8696 for controlling concepts.

{Processes characterised by a specific catalyst}
References relevant to classification in this group
This subgroup does not cover:

Catalysts for engine exhaust gases (e.g. from cars)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

Concepts classified here must further specify the catalytic substance in B01D 2255/00.

{Ammonia}
References relevant to classification in this group
This subgroup does not cover:

Catalysts for internal combustion engines (e.g. cars)

{Simultaneous elimination of the components (B01D 53/8656 takes precedence)}
Definition statement
This subgroup covers:

Process related concepts with known three-way-catalyst (TWC) compositions.

References relevant to classification in this group
This subgroup does not cover:

Three-way-catalysts for engine exhaust gases (e.g. cars):

Successive elimination of the components

Special rules of classification within this group

This group may be combined with B01D 53/8696 for controlling concepts.

{characterised by a specific catalyst}
References relevant to classification in this group
This subgroup does not cover:

Three-way-catalysts for engine exhaust gases (e.g. cars)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

Concepts classified here must further specify the catalytic substance in B01D 2255/00.

{characterised by a specific device}
Definition statement
This subgroup covers:

Apparatus (mechanics) related concepts with known catalytic substances.

References relevant to classification in this group
This subgroup does not cover:

Three-way-catalysts for internal combustion engines (e.g. cars)

{Successive elimination of the components}
Definition statement
This subgroup covers:

Concepts including the sequential removal of carbon monoxide or hydrocarbons and nitrogen oxides.

References relevant to classification in this group
This subgroup does not cover:

Sequential removal for gases from internal combustion engines (e.g. cars):

{Removing halogens or halogen compounds}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Exhaust treatment in chemical vapour deposition processes

Special rules of classification within this group

Halogens to be removed can further be specified in B01D 2257/00. Other symbols from B01D 2255/00 and B01D 2258/00 should be allocated where appropriate.

{Organic halogen compounds}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Exhaust treatment in chemical vapour deposition processes

Special rules of classification within this group

Halogens to be removed can further be specified in B01D 2257/00. Other symbols from B01D 2255/00 and B01D 2258/00 should be allocated where appropriate.

{Removing heavy metals or compounds thereof, e.g. mercury}
Special rules of classification within this group

Symbols from B01D 2255/00, B01D 2257/00 and B01D 2258/00 should be allocated where appropriate.

{Removing organic compounds not provided for in B01D 53/8603 to B01D 53/8665}
Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the catalyst used and the component to be removed B01D 2255/00, B01D 2257/00.

{Removing components of defined structure not provided for in B01D 53/8603 to B01D 53/8668}
Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the catalyst used and the component to be removed B01D 2255/00, B01D 2257/00.

{Removing components of undefined structure}
Special rules of classification within this group

This group should, if sensible, be allocated in combination with symbol specifying the catalyst used B01D 2255/00 and the origin of the waste gas B01D 2258/00.

Examples of such gases are flue gases from power plants, blast furnaces or waste incinerators.

{Multiple step processes}
Definition statement
This subgroup covers:

Sequential catalytic treatment of waste gases comprising two or more catalytic steps.

References relevant to classification in this group
This subgroup does not cover:

A multistep treatment comprising only one catalytic step

Special rules of classification within this group

Single treatment steps may be allocated the Indexing Code B01D 53/00.

{After-treatment of removed components}
Special rules of classification within this group

Symbols for specifying the removed components should be allocated.

{Controlling the catalytic process}
References relevant to classification in this group
This subgroup does not cover:

Controlling catalytic processes involving internal combustion engines

Informative references
Attention is drawn to the following places, which may be of interest for search:

Investigating or analysing materials by determining their chemical or physical properties

Controlling or regulating systems or variables

Special rules of classification within this group

This group should be allocated in combination with another group and/or symbol specifying the component to be removed.

Handling or mounting catalysts
Definition statement
This subgroup covers:

Concepts related to mechanical appliances of catalytic material on structures or apparatus.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

This group should be allocated in combination with symbol notably for specifying the catalyst B01D 2255/00 and the component to be removed B01D 2257/00.

A frequent example is the application of a photo-catalytic material (B01D 2255/802) onto a structure.

{Devices in general for catalytic purification of waste gases}
Relationship between large subject matter areas

Catalysts in general

Special rules of classification within this group

This group should be allocated in combination with symbol notably for specifying the catalyst B01D 2255/00 and the component to be removed B01D 2257/00.

A frequent example is the application of a photo-catalytic material (B01D 2255/802) onto a structure.

Injecting reactants
Informative references
Attention is drawn to the following places, which may be of interest for search:

Exhaust treatment aspects for vehicles

Special rules of classification within this group

This group should be allocated in combination with symbol notably for specifying the reactant B01D 2251/00, the catalyst B01D 2255/00 and the component to be removed B01D 2257/00.

A common example for an injected reactant is a liquid reducing agent such as ammonia.

of engine exhaust gases (exhaust{or silencing}apparatus{for internal combustion engines, machines or engines in general}, having means for purifying,{rendering innocuous} or otherwise treating exhaust gases F01N 3/00)
Definition statement
This subgroup covers:

The groups B01D 53/92 to B01D 53/927 cover all treatment concepts for engine exhaust gases except catalytic treatment

References relevant to classification in this group
This subgroup does not cover:

Catalytic treatment concepts for engine exhaust gases

Informative references
Attention is drawn to the following places, which may be of interest for search:

Exhaust treatment aspects for vehicles

Exhaust or silencing apparatus for internal combustion engines, machines or engines in general, having means for purifying, rendering innocuous or otherwise treating exhaust gases

Special rules of classification within this group

The groups B01D 53/92 to B01D 53/927 can be combined with other groups or symbol chosen from B01D 53/00 to B01D 53/96 to characterise the treatment concept.

by catalytic processes
References relevant to classification in this group
This subgroup does not cover:

Catalytic processes not involving engine exhaust gases

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Exhaust treatment aspects for vehicles

Special rules of classification within this group

All groups B01D 53/94 to B01D 53/9495 should, if sensible, be allocated in combination with symbol specifying the catalytic substances used B01D 2255/00.

{Nitrogen oxides}
Definition statement
This subgroup covers:

Process related concepts (e.g. controlling) with known catalyst compositions.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling combustion engines

Special rules of classification within this group

This group can be combined with B01D 53/9495 for controlling concepts.

{Processes characterised by a specific catalyst}
References relevant to classification in this group
This subgroup does not cover:

Removing nitrous oxides (N2O) B01D 53/9427.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

Symbols specifying the catalytic substance are to be allocated B01D 2255/00.

{for removing nitrogen oxides by selective catalytic reduction (SCR) using a reducing agent in a lean exhaust gas}
Definition statement
This subgroup covers:

Concepts where the reducing agent is added under constant lean exhaust gas conditions.

References relevant to classification in this group
This subgroup does not cover:

Adding reducing agent under alternating lean and rich exhaust gas conditions

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

Symbols specifying the catalytic substance are to be allocated B01D 2255/00.

{for removing nitrogen oxides by NOx storage or reduction by cyclic switching between lean and rich exhaust gases (LNT, NSC, NSR)}
Definition statement
This subgroup covers:

Concepts where the reducing agent is added under alternating lean and rich exhaust gas conditions.

References relevant to classification in this group
This subgroup does not cover:

Adding reducing agent under constant lean exhaust gas conditions

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Controlling exhaust gas conditions with means other than the combustion engine

Controlling combustion engines (e.g. lambda value)

Special rules of classification within this group

Symbols specifying the catalytic substance are to be allocated B01D 2255/00.

{for removing nitrous oxide}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

Symbols specifying the catalytic substance are to be allocated B01D 2255/00.

{Processes characterised by a specific device}
Definition statement
This subgroup covers:

Apparatus (mechanics) related concepts with known catalytic substances.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Exhaust treatment systems in vehicles

{Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts (TWC) B01D 53/9445)}
Definition statement
This subgroup covers:

Oxidation catalysts (e.g. DOC) and filters coated with oxidation catalysts;

References relevant to classification in this group
This subgroup does not cover:

Catalysts for gasoline engines (except lean burn engines)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Three-way-catalysts (TWC)

Special rules of classification within this group

If applicable, this group should be given in combination with symbols chosen from B01D 2255/902 and B01D 2255/903.

Further Indexing Codes specifying the catalytic substance are to be allocated B01D 2255/00, notably B01D 2255/915.

{Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts (TWC) or four-way-catalysts (FWC)}
Definition statement
This subgroup covers:

Process related concepts (e.g. controlling) with known catalyst compositions.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling combustion engines

Special rules of classification within this group

This group can be combined with B01D 53/9495 for controlling concepts.

{characterised by a specific catalyst}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

Symbols specifying the catalytic substance are to be allocated B01D 2255/00.

{characterised by a specific device}
Definition statement
This subgroup covers:

Apparatus (mechanics) related concepts with known catalytic substances.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Exhaust treatment systems in vehicles

{Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts (layered catalysts with only one function B01D 53/9413 , B01D 53/944 or B01D 53/945)}
Definition statement
This subgroup covers:

Processes and apparatuses where the gas successively passes different catalysts (including zone-coated catalysts and wall-flow filters with different coatings on inlet and outlet channels)

Informative references
Attention is drawn to the following places, which may be of interest for search:

Layered catalysts with only one function

Special rules of classification within this group

Symbols to be allocated are notably selected from B01D 2255/902, B01D 2255/903, B01D 2255/904 and B01D 2255/9155

{with catalysts positioned on one brick}
Special rules of classification within this group

Symbols specifying the catalytic substance are to be allocated B01D 2255/00.

{in different layers}
Definition statement
This subgroup covers:

Wall-flow filters with different layers on the walls.

References relevant to classification in this group
This subgroup does not cover:

Layered catalysts on flow through substrates are generally not regarded as having different successive functions

Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

Symbols specifying the catalytic substance are to be allocated B01D 2255/00, notably B01D 2255/902.

{in different zones}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Catalysts in general

Special rules of classification within this group

Symbols specifying the catalytic substance are to be allocated B01D 2255/00, notably B01D 2255/903.

{with catalysts positioned on separate bricks, e.g. exhaust systems}
Definition statement
This subgroup covers:

Exhaust systems where a specific sequence of catalytic functions is given, for example DOC-DPF or LNT-SCR. It also covers exhaust systems where the DPF is not coated.

Special rules of classification within this group

This group is also given if a specific order is indicated and the DPF has no catalytic function.

Symbols specifying the catalytic substance are to be allocated B01D 2255/00.

{Controlling the catalytic process}
Informative references
Attention is drawn to the following places, which may be of interest for search:

Controlling combustion engines (e.g. lambda value)

Special rules of classification within this group

This group should be allocated in combination with another group and/or additional information symbols specifying the treatment concept B01D 53/94 to B01D 53/949.

Regeneration, reactivation or recycling of reactants
Special rules of classification within this group

This group should, if sensible, be allocated in combination with another group or symbols specifying the reactant used B01D 2251/00 or B01D 2252/00, component to be removed B01D 2257/00 or the treatment concept, e.g. B01D 53/00.

Separation, other than separation of solids, not fully covered by a single other group or subclass, e.g. B03C
Definition statement
This group covers:

Any process for separation not fully covered by any of the other groups in B01D provided that it is not related to the separation of solid particles.

References relevant to classification in this group
This group does not cover:

Separation by distillation

Separation by extraction

Separation by sorption

Separation of liquids from liquids

Degasification of liquids

Dead end filtration processes

Gas separation

Membrane separation processes

Informative references
Attention is drawn to the following places, which may be of interest for search:

Electrodialysis and electro-osmosis

Analysis processes using electrophoresis

Treatment of water, waste water, sewage, or sludge by electrochemical separation

Electrophorectic production of compounds or non-metals

Preparation of peptides by electrophoresis

Dielectrophoresis

Special rules of classification within this group

In general, the relevant subgroup is given and not the head group. If more than one subgroup of a single head group is relevant for a document, all these relevant sub groups are given.

by electrophoresis (treatment of water, waste water, sewage or sludge by electrophoresis C02F 1/469 ; electrophoretic production of compounds or non-metals C25B 7/00 ; investigating or analysing materials by using electrophoresis G01N 27/26)
Definition statement
This subgroup covers:

B01D 57/02 includes only processes involving migration of species due to an electrical potential in the absence of any kind of separation membrane. Otherwise the respective subgroups of B01D 61/42 apply. The class is given for preparative purposes only (opposed to investigation or analysis purposes).

Informative references
Attention is drawn to the following places, which may be of interest for search:

Treatment of water, waste water, sewage or sludge by electrophoresis

Electrophoretic production of compounds or non-metals

Investigating or anaylsing materials by using electrophoresis

Separation of different isotopes of the same chemical element (preventing occurrence of critical conditions when producing fissile material G21; shielding from radioactivity G21F)
Definition statement
This group covers:

The separation of isotopes of the SAME element. A starting compound comprising several isotopes of the same element is separated in at least two fractions wherein each fraction is enriched/depleated in a least one of the isotopes in comparison with the starting material and with the other fraction(s). This implies that the difference in isotopes ratios is not only due to radioactive decay

Relationship between large subject matter areas

Preventing occurrence of critical conditions when producing fissile material G21; shielding from radioactivity G21F

References relevant to classification in this group
This group does not cover:

The preparation of nuclides, (e.g. for medical purposes) from other elements (e. g. preparation of 99Tc from 99Mo and their separation from the mother solution (when these are not separated from other isotopes of the same element (otherwise B01D 59/00).

Mass spectrometers.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Preventing occurence of critical conditions when producing fissile material

G21

Shielding from radioactivity

Synonyms and Keywords

In patent documents the following expressions/words “isotopes” and “nuclides” are often used as synonyms.

Separation by mass spectrography (particle spectrometer or separator tubes H01J 49/00)
Definition statement
This subgroup covers:

Processes for separating isotopes by using mass spectrometers.

References relevant to classification in this group
This subgroup does not cover:

Mass spectrometers

Separation involving two or more processes covered by different groups selected from groups B01D 59/02 , B01D 59/10 , B01D 59/20 , B01D 59/22 , B01D 59/28 , B01D 59/34 , B01D 59/36 , B01D 59/38 , B01D 59/44
Special rules of classification within this group

Document relating to isotopes separation using more than one process should get the class B01D 59/50 and symbols (depending on the information disclosed) of each of separation process (B01D 59/10, B01D 59/20, B01D 59/22, B01D 59/28, B01D 59/34, B01D 59/36, B01D 59/38, B01D 59/44).

Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis, ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
Definition statement
This group covers:

Processes for separation of liquid feed by means of a membrane in general which selectively allows passage of components from liquid feed mixtures including suspensions of particles, heterogeneous or homogeneous mixtures.

These types of membrane processes include:

  • Pressure driven membrane separation processes as microfiltration, ultrafiltration, nanofiltration, reverse osmosis,
  • Concentration gradient based membrane separation as forward osmosis, dialysis
  • Membrane separation processes based on an electrical gradient such as electrodialysis, electro-osmosis and electro-ultrafiltration
  • Thermally based separation processes (based on a gradient of the activities of a component) as pervapouration, membrane distillation
  • Processes applying liquid separation membranes; either immobilised in a porous matrix or in suspension
  • Sequences applying combinations of such membrane processes

For microfiltration processes only cross-flow processes, i.e. applying a tangential flow of the feed solution over the membrane) are considered.

Relationship between large subject matter areas

A close relationship exists between membrane microfiltration and the field of filtration (B01D 25/00 - B01D 35/00).

Generally all cross-flow filtration applications (control of deposits on the filter) are regarded as falling into B01D 61/00-B01D 61/58, while dead end filters (cake filtration) should be covered by the filtration groups.

References relevant to classification in this group
This group does not cover:

Membrane modules for membrane separation

Membrane cleaning or sterilisation

Prevention of membrane fouling

Membrane testing

Degasification of liquids by filtration (i.e. with membranes)

Processes for separation of gases or vapour by means of membranes

Electrophoresis for separation

Dead end filtration processes and devices

Blood dialysis systems and blood oxygenation processes with membranes

Filtering material out of the blood by passing it through a membrane, i.e. haemofiltration, diafiltration

Bandages or dressings

Galenical forms by sustained drug release by osmosis

Drug containing films, membranes or sheets

Methods or apparatus for sterilizing material using filtration

Membrane reactors

Feeding or removing reactants or products to or from the catalyst bed of a reactor through a membrane

Separation of hydrogen by diffusion

Preparation of oxygen by making use of membranes

Purification or separation of nitrogen by making use of membranes

Physical processing of noble gases by making use of membranes

Purification of acylic or carboxylic compounds using membranes

Working up of undefined normally gaseous mixtures using membranes

Enzymology or microbiology with dialysis means

Tissue, human, animal or plant cell or virus culture apparatus with ultrafiltraiton, inverse osmosis or dialysis means

Extracting or separation of nucleic acids from biological sampels by membranes

Electrolysis

Pressure retarded osmosis

Osmotically driven micro pumps

Fuel cells

Batteries comprising separators

Informative references
Attention is drawn to the following places, which may be of interest for search:

Treatment of water, waste water, sewage, or sludge by means of by dialysis, osmosis or reverse osmosis

Treatment of water, waste water, sewage, or sludge by electrochemical separation

Multistage treatment of water, waste water, or sewage

Multistage treatment of water with portable or detachable small-scale treatment devices

Milk preparation by dialysis, reverse osmosis or ultrafiltration

Milk preparation by electrodialysis

Cheese preparation by dialysis or ultrafiltration

Concentration or drying of juices by membrane processes

Clarifying or fining of non-alcoholic beverages using membranes

Preparation of peptides by ultrafiltration or reverse osmosis

Working up used lubricants by ultrafiltration or osmosis

Refining or fats or fatty oils including ultrafiltration or dialysis

Preparation of other alkoholic beverages using membranes

Refining hydrocarbon oils by dialysis

Dewatering or demulsification of hydrocarbon oils by filtration

Removal of precipitate or added materials from alcoholic beverages by filtration

Purification of sugar juices using membranes

Apparatus for feeding liquid fuel having water separation means as membranes

Special rules of classification within this group
  • Classification in multiple groups:

In case a specific application is addressed the respective application class/group takes precedence.

As long as no details on the membrane process or the apparatus for carrying out said process are disclosed, no groups from B01D 61/00-B01D 61/58 are given in addition.

However if such details are given, the respective B01D 61/00-B01D 61/58 group should be given in addition.

  • Subgroup and main group:

In general, the relevant subgroup is given and not the head group. If more than one subgroup of a single head group is relevant for a document, all these relevant sub groups are given.

  • Classification of additional information:

The classification of additional information is obligatory and useful for retrieving documents.

Often, aspects of cleaning, maintenance or stable operation are disclosed in connection with the processes. These information is to be classified under CPC groups B01D 65/02, B01D 65/08 and the symbols under B01D 2321/00.

The following groups relate to specific fields of application for the membrane processes falling into B01D 61/00-B01D 61/58.

This does not exclude that also groups from B01D 61/00-B01D 61/58 are given in addition.

As long as no details on the membrane process or the apparatus for carrying out said process are disclosed, no groups from B01D 61/00-B01D 61/58 are given in addition.

However if such details are given, the respective B01D 61/00-B01D 61/58 group should be given in addition.

  • Further details of subgroups:

includes sequences of reverse osmosis (RO) steps, sequences of nanofiltration (NF) steps as well as mixed RO-NF sequences.

In cases when ultrafiltration/ microfiltration is only a prefiltration step for reverse osmosis or nanofiltration B01D 61/04 applies.

B01D 61/08 and B01D 61/18 apply in case a whole membrane plant structure suitable to carry out a membrane process is addressed. Includes also microfluidic devices. Membrane modules as such are in B01D 63/00.

B01D 61/10 and B01D 61/20 apply for specific parts of the membrane plant not being the membrane module (e.g. specific pumps, valves, heat exchangers etc.) and which are not relevant for the module alone, which is covered by B01D 65/00.

includes sequences of ultrafiltration (UF) steps, sequences of microfiltration (MF) steps as well as mixed MF-UF sequences.

The group includes microfiltration processes only of the cross-flow type (i.e. no dead-end). Dead end filtration is covered by B01D 25/00-B01D 35/00.

The group includes all combinations of different processes of any of the groups of B01D 61/00 beside mixed RO-NF (B01D 61/022) or mixed UF-MF (B01D 61/142) processes.

The groups under B01D 2311/00 specify details to the membrane separation process and control (as controlled parameters or additional unit operations involved).

The groups under B01D 2315/00 specify details relating to the membrane module operation (e.g. batch processes or submerged operation).

The groups under B01D 2317/00 specify the membrane module arrangements within a plant or an apparatus (e.g. series/parallel connections).

The groups under B01D 2319/00 specify the membrane module arrangements within a single housing (e.g. series/parallel connections).

Apparatus in general for separation processes using semi-permeable membranes
Definition statement
This group covers:

Modules for membrane based separation processes. These modules could be suitable for both liquid (B01D 61/00-B01D 61/58) and/or gaseous (B01D 53/22) feed/ permeate streams.

The devices classified in this group provide details on the integration of a selective separation membrane into a technically applicable module concept as e.g.:

  • a membrane plate with support structure, closed edges and permeate duct
  • a spiral wound module with permeate core pipe
  • a hollow fibre type module potted in tube sheets
  • a rotating membrane disc mounted to a shaft
  • tubular membrane module
  • flat membrane module
  • pleat-type membrane module,
  • rotary, reciprocated or vibrated module

The technical concept may include membrane fixing or sealing means or certain feed or permeate side ducts or spaces.

Relationship between large subject matter areas

The groups for apparatus specifically adapted for a certain membrane separation process classified in B01D 61/08, B01D 61/18, B01D 61/28 and B01D 61/46 concern a plant wide concept of design. This does not exclude that a specific module concept is disclosed in combination to this concept which is then classified in B01D 63/00 in addition, if applicable.

If a document does not focus on the concept of incorporation of the membrane into the module but on membrane unrelated details (e.g. housing, end caps or locks), the relevant classification would be B01D 65/00. This does not exclude that a specific module concept is disclosed in combination to this concept which is then classified in B01D 63/00 in addition, if applicable.

A specific structure of the membrane as such (like the cross-sectional structure of a hollow fibre or a membrane with surface irregularities is classified in the relevant B01D 69/00 groups.

References relevant to classification in this group
This group does not cover:

Dead end filtration devices

Blood dialysis systems, blood oxygenation devices and blood filtration devices with do not focus on the design of the membrane module as such

Membrane reactors

Fuel cells

Batteries comprising separators

Bandages or dressings

Drug containing films, membranes or sheets

Methods or apparatus for sterilizing material using filtration

Enzymology or microbiology with dialysis means

Tissue, human, animal or plant cell or virus culture apparatus with ultrafiltration, inverse osmosis or dialysis means

Honeycomb structures not relevant for membrane separation (silencers, catalysts etc.)

Osmotically driven micro pumps

Informative references
Attention is drawn to the following places, which may be of interest for search:

Separation of gases or vapours by diffusion

Drying gases or vapours by filtration

Separation of different isotopes of the same chemical element by diffusion, solvent extraction

Processes of separation using semi-permeable membranes

Details of membrane modules not related to the membrane parts such as housing or locks

Membrane bonding or sealing

Membrane apparatus specifically adapted for a reverse osmosis or nanofiltration process

Membrane apparatus specifically adapted for an ultrafiltration or microfiltration process

Apparatus for dialysis

Apparatus for electrodialysis

Processes specially adapted for manufacturing semi-permeable membrane for separation processes

Semi-permeable membranes for separation processes characterised by their form, structure

Material of semi-permeable membrane for separation processes

Treatment of water, waste water, sewage, or sludge by means of by dialysis, osmosis or reverse osmosis

Treatment of water, waste water, sewage, or sludge by electrochemical separation

Mobile apparatus and plants, e.g. mounted on a vehicle

Membrane bioreactors

Multiwell filters

Apparatus for feeding liquid fuel having water separation means as membranes

Devices for degassing fuel

Humidifier for fuel cells

Honeycomb catalysts and wall flow filters

Special rules of classification within this group
  • Classification of additional information

The classification of additional information is very desirable and useful for retrieving documents:

The groups under B01D 2313/00 specify details to the membrane modules

groups codes under B01D 2319/00 specify the membrane module arrangements within a single housing (e.g. series/parallel connections).

  • Subgroup and main group

In general, the relevant subgroup is given and not the head group. If more than one subgroup of a single head group is relevant for a document, all these relevant sub groups are given.

Membrane separation modules as such are to be classified in B01D 63/00- B01D 63/16 only despite their field of application (e.g. though gas separation processes with membrane are classified in B01D 53/22, the modules as such are to be classified in B01D 63/00- B01D 63/16 only).

Usually all stand-alone types of modules are classified in B01D 63/00 unless they are integral part of a specific device such as e.g. lab-on-a-chip, multi-well membrane filters, gas detectors, implantable dialysis means or degasification means in ink jet cartridges.

  • Further details of subgroups

The group B01D 63/00 is used for module concepts not falling in any of the groups.

applies for honeycomb structures with through-going channels, i.e. suitable for cross-flow. The structural similar exhaust gas filters (wall flow filters) and catalysts with channels closed at one end are not classified here. (cf. off-gas treatment groups B01D 2255/915 and B01D 2255/9155). The subgroups of B01D 69/04 do not apply for honeycomb structures.

covers tubular membranes bent/ pleated along its length dimension (e.g. u-shape) while the group B01D 63/16 covers pleated flat membranes (often arranged in a closed circle).

The group B01D 63/16 partly overlaps with the corresponding apparatus classes in B01D 33/00 (filters with moving elements) , esp. B01D 33/15. The documents are classified with respect to their intended application, i.e. if one of the applications falling under B01D 61/00 is covered, B01D 63/16 would apply.

The groups under B01D 2315/02 and B01D 2315/04 further specify membrane module arrangements falling under B01D 63/16.

Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
Relationship between large subject matter areas

All respective accessories and procedures applied for dead end filtration devices and process according to B01D 25/00-B01D 35/00 are to be classified even if they are suitable to be used in connection with membrane devices and processes without modification. They have to be considered during search.

References relevant to classification in this group
This group does not cover:

Membrane modules as such

Accessories specifically adapted for a reverse osmosis or nanofiltration process

Accessories specifically adapted for an ultrafiltration or microfiltration process

Accessories specifically for apparatus for dialysis

Accessories specifically for apparatus for electrodialysis

Accessories and auxiliary operations of dead end filtration devices

Accessories and auxiliary operations specifically for apparatus for blood dialysis and filtration

Regeneration of electrodialysis devices

Aerating systems for activated sludge systems

Cleaning and fouling prevention in general

Testing of material in general

Informative references
Attention is drawn to the following places, which may be of interest for search:

Sterilisation of dialysis devices

Sterilisation in general

Water treatment processes by membrane technology

Investigating permeability, pore-volume, or surface area of porous materials

Special rules of classification within this group
  • Classification of additional information

The classification of additional information is obligatory and useful for retrieving documents:

For membrane cleaning processes B01D 65/02 is given together with the relevant symbols under B01D 2321/00 which specify details of membrane cleaning operations.

For measures for fouling prevention B01D 65/08 is given together with the relevant symbols under B01D 2321/00 which specify details of membrane fouling prevention operations.

  • Subgroup and main group

In general, the relevant subgroup is given and not the head group. If more than one subgroup of a single head group is relevant for a document, all these relevant subgroups are given.

  • Further details of subgroups

B01D 65/00 and B01D 65/003 are given together with the relevant groups under B01D 2313/00 which specify details to the membrane modules and apparatus which might be of relevance.

B01D 65/00: Accessories for modules and membrane plants which are not directly interrelated with a specific module type, e.g. end caps B01D 65/00 or membrane sealing B01D 65/003

B01D 65/006 applies for the storage of membrane modules while B01D 67/0097 applies for the storage of membrane material only.

Membrane cleaning and sterilisation, i.e. actions taken or means specifically designed for treating the membrane in between cycles of steady filtration operation.

B01D 65/02 and B01D 65/08 are to be classified in combination with their relevant groups under B01D 2321/00.

When aeration occurs during filtration operation B01D 65/08 applies. When aeration takes place during cleaning cycles B01D 65/02 applies. Combinations of both afford to give both groups.

The application of usual cross-flow conditions are not classified in B01D 65/08

If the process control is of relevance for either membrane cleaning or prevention of membrane fouling the respective control groups of B01D 61/00 have to be given if applicable in combination with the relevant groups under B01D 2311/00.

Groups B01D 65/04 and B01D 65/06 are not used.

Prevention of membrane fouling, i.e. actions taken or means specifically designed for influencing the steady state operation conditions such that fouling is controlled (e.g. aeration during filtration or static mixers etc.).

Testing or membranes or membrane apparatus, i.e. devices and methods for determining integrity of membrane and/or the whole module or for determining characteristic parameters as retention, permeability etc.

Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
Definition statement
This group covers:

Processes for the production of membranes for separation applications per se, i.e. including the production of the selective layer if applicable onto the support structure or self-supporting.

Semipermeable membranes comprise a continuous layer of material with or without pores capable for mass transfer of a certain species, solvent or gas.

Further process for after-treatment of a membrane are covered under B01D 67/0081

Relationship between large subject matter areas

Production of hollow fibre membranes under B01D 69/08.

Production of specific shapes of membranes in the relevant subgroups of B01D 69/00.

Filter materials using woven or non-woven selective layers or loose particles for separation purposes are to be classified in B01D 39/00.

All of the following fields have own classification schemes for manufacture:

Membrane electrodes specifically manufactured/ adapted for the application in fuel cells (H01M 8/1018 and subgroups).

The production of ion exchange material films/ membranes (C08J 5/22).

Production of battery separators (C08J 5/22, H01M 2/14)

Double classification with B01D 67/00 may occur if the structures produced are suitable to be used in membrane separation processes.

C08 covers organic macromolecular compounds, their preparation or chemical working-up and compositions based thereon. Unless no details on the preparation of a separation membrane made of these components is described, B01D 67/00 is not relevant.

References relevant to classification in this group
This group does not cover:

Membrane material as such

Hollow fibre membrane production

Form, structure or properties of membrane materials

Production of catalysts by surface coating processes

Micro structural devices

Shaping by streching

Surface coating to prevent activation of blood

Electroless plating in general

Aluminium anodisation in general

Surface treatment with plasma in general

After-treatment of mortars, concrete, artificial stone or ceramics by coating or impregnating

Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by moulding material on a relative small portion (e.g. hollow fibre potting) of the preformed parts

Manufacture of films of plastics

Informative references
Attention is drawn to the following places, which may be of interest for search:

Micromachined membranes

Constructional details or processes of manufacture of separators, membranes, diaphragms for batteries

Manufacture of shaped structures of ion- exchange resin films, membranes, or diaphragms

Membranes for fuel cells

Manufacture of hollow fibre membranes

Separate or in situ-formation of thin film membranes

Special rules of classification within this group

Classification in multiple groups

If only the preparation of the support is defined in detail group B01D 69/10 takes precedence.

Classification of additional information

If the membrane manufacturing process is defined for a specific material or group of materials the relevant groups under B01D 71/00 have to be given in addition.

The classification of additional information is obligatory and useful for retrieving documents:

The groups under B01D 2323/00 specify details to the membrane manufacturing methods

The respective groups under B01D 61/00 if a membrane is specifically produced for a membrane process (as e.g. nanofiltration; B01D 61/027).

B01D 69/02 in combination with the relevant groups under B01D 2325/00 have to be used if the manufacturing process results in specific properties of the membrane product.

Subgroup and main group

In general, the relevant subgroup is given and not the head group. If more than one subgroup of a single head group is relevant for a document, all these relevant subgroups are given.

Further details of subgroups

In cases of membrane formation by in situ interfacial polymerisation group B01D 69/125 should be given in addition to the B01D 67/0006.

Group B01D 67/0079 concerns membrane active layers comprising both organic and inorganic materials (as e.g. mixed matrix membranes in B01D 69/148). Structures e.g. comprising an inorganic support and an organic separation layer are also to be classified in B01D 67/0079, however in addition in B01D 69/10 (specific support) if applicable. In addition the materials of the individual layers should be given as groups under B01D 71/00.

The after treatment classes under B01D 67/0081 apply if the membrane separation layer structure is basically maintained but modified in its properties (e.g. rendered hydrophilic or coated without closing the pores).

If specific (e.g. charged) groups are added to the polymer solution before membrane formation B01D 71/82 takes precedence before B01D 67/0093.

Grafting supported by radiation or plasma is classified in B01D 67/0093.

Group B01D 67/0097 applies for the storage of membrane material only while B01D 65/006 applies for the storage of membrane modules.

has to be used if details of the manufacturing apparatus are given (dies, roller arrangements, treatment chambers).

Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
Relationship between large subject matter areas

Production of membranes per se under B01D 67/00.

Production of membrane modules under B01D 63/00.

Filter materials using woven or non-woven selective layers or loose particles for separation purposes are to be classified under B01D 39/00.

All of the following fields have own classification schemes for manufacture:

Membrane electrodes specifically manufactured/ adapted for the application in fuel cells (H01M 8/1018 and subgroups).

The production of ion exchange material films/ membranes (C08J 5/22).

Production of battery separators (C08J 5/22, H01M 2/14)

Double classification with B01D 67/00 may occur if the structures produced are suitable to be used in membrane separation processes and are relevant for any of the groups in B01D 69/00.

References relevant to classification in this group
This group does not cover:

Membrane modules

Production processes for membranes other than hollow fibre spinning

Membrane material as such

Production of catalysts by surface coating processes

Micro structural devices

Shaping by streching

Surface coating to prevent activation of blood

Electroless plating in general

Aluminium anodisation in general

Surface treatment with plasma in general

After-treatment of mortars, concrete, artificial stone or ceramics by coating or impregnating

Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by moulding material on a relative small portion (e.g. hollow fibre potting) of the preformed parts

Manufacture of films of plastics

Diffusers made of flexible or rigid material

Tubular air diffusers

Catalysts, in general, characterised by their form or physical properties in the form of membranes

Hoses and pipes made of rubber

Informative references
Attention is drawn to the following places, which may be of interest for search:

Micromachined membranes

Constructional details or processes of manufacture of separators, membranes, diaphragms for batteries

Manufacture of shaped structures of ion- exchange resin films, membranes, or diaphragms

Membranes for fuel cells

Manufacture of hollow fibres

Manufacture of hollow fibres/ spinnerets therefore

Formation of filaments (e.g. electro-spinning

Special rules of classification within this group

Classification of additional information

If the membrane manufacturing process is defined for a specific material or group of materials the relevant groups under B01D 71/00 have to be given in addition. In case of multiple layers the material of each layer has to be specified by the respective groups under B01D 71/00.

The classification of additional information is obligatory and useful for retrieving documents:

The symbol under B01D 61/00 is to be used if a membrane is specifically produced for a certain membrane process (as e.g. nanofiltration; B01D 61/027).

Subgroup and main group

In general, the relevant subgroup is given and not the head group. If more than one subgroup of a single head group is relevant for a document, all these relevant subgroups are given.

Further details of subgroups

B01D 69/02 in combination with the relevant groups under B01D 2325/00 have to be used if the manufacturing process results in specific properties of the membrane product.

does not in any case apply for honeycomb structures/ monoliths with multiple channels. These kind of devices are rather classified in B01D 63/066. If e.g. special cross-sectional shaped of the channels or surface undulations are present groups under B01D 69/04 can be given in addition.

Specific forms of membranes for separation other than the materials as such.

Spinning processes and spinnerets for hollow fibres

Specific membrane supports.

B01D 69/10 is used for supports not bonded to the selective membrane layer, if only details of the support layer are defined or if the type of support is very unique (as e.g. membranes supported in the pores).

Composite membranes, i.e. comprising more than one layer, the layers being integrated.

used if support and selective membrane layer form a composite structure, in which both parts are relevant (e.g. by means of the type of bonding or membrane formation or relation of parameters of the support and the selective layer).

groups B01D 69/122 and B01D 69/125 cover the manufacturing of ultra-thin (Thin film) membranes on a support and are given in addition to the relevant classes in B01D 67/00.

Mixed matrix membranes, i.e. the separation layer comprises a heterogeneous mixture of at least two materials.

applies if the composition of the membrane solution is relevant for the coagulation process.

Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
Definition statement
This group covers:

Membranes characterised by a specific material used for the separation layer and methods of preparation specifically adapted for the respective material (e.g. a specific polymer synthesis).

Relationship between large subject matter areas

Generally the production methods of membranes is covered under B01D 67/00.

Production of specific shapes of membranes in the relevant sub groups of B01D 69/00.

Gas separation membranes characterised by their material are additionally classified under B01D 53/228.

Filter materials using woven or non-woven selective layers or loose particles for separation purposes are to be classified in B01D 39/00.

All of the following fields have own classification schemes for manufacture:

Membrane electrodes specifically manufactured/ adapted for the application in fuel cells (H01M 8/1018 and subgroups).

The production of ion exchange material films/ membranes (C08J 5/22).

Production of battery separators (C08J 5/22, H01M 2/14)

Double classification with groups of B01D 67/00 may occur if the structures produced are suitable to be used in membrane separation processes.

C08 covers organic macromolecular compounds, their preparation or chemical working-up and compositions based thereon. Unless no preparation of a separation membrane thereof is described, these classes are not relevant.

References relevant to classification in this group
This group does not cover:

Membrane production methods

Hollow fibre membrane production

Form, structure or properties of membrane materials

Production of catalysts by surface coating processes

Micro structural devices

Shaping by stretching

Surface coating to prevent activation of blood

Electroless plating in general

Aluminium anodisation in general

Surface treatment with plasma in general

After-treatment of mortars, concrete, artificial stone or ceramics by coating or impregnating

Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by moulding material on a relative small portion (e.g. hollow fibre potting) of the preformed parts

Manufacture of films of plastics

Sorbents; zeolites, synthetic molecular sieves

Catalysts comprising molecular sieves; zeolites

Compounds having molecular sieve and base exchange properties

Informative references
Attention is drawn to the following places, which may be of interest for search:

Micromachined membranes

Constructional details or processes of manufacture of separators, membranes, diaphragms for batteries

Manufacture of shaped structures of ion- exchange resin films, membranes, or diaphragms

Membranes for fuel cells

Manufacture of hollow fibres

Manufacture of hollow fibres/ spinnerets therefore

Characteristic membranes for the separation of hydrogen by diffusion

Characteristic membranes for the preparation of oxygen by making use of membranes

Characteristic membranes for the purification or separation of nitrogen by making use of membranes

Characteristic membranes for the physical processing of noble gases by making use of membranes

Special rules of classification within this group

Classification of additional information

If the membrane manufacturing process is defined for a specific material or group of materials the relevant groups under B01D 71/00 have to be given in addition.

The classification of additional information is obligatory and useful for retrieving documents:

The group B01D 69/02 in combination with the relevant groups under B01D 2325/00 have to be used if the manufacturing process results in specific properties of the membrane product.

The respective groups under B01D 61/00 is to be used if a membrane is specifically capable for a certain membrane process (as e.g. nanofiltration; B01D 61/027).

If a mixed matrix membrane is classified under B01D 69/141 the material classification symbol of B01D 71/00 of the continuous phase is to be given in addition if relevant.

For a blend of two polymers in the separation layer both relevant groups are given.

Support materials according to B01D 69/10 are not classified under B01D 71/00.

In general, the relevant subgroup is given and not the head group. If more than one subgroup of a single head group is relevant for a document, all these relevant subgroups are given.

Further details of subgroups

The individual copolymers in B01D 71/76 have to be classified with symbols under B01D 71/00.

B01D 71/78 is to be given if a polymer is grafted before membrane formation. Otherwise B01D 67/0093 applies.

B01D 71/82 is to be given if a polymer solution is treated before membrane formation by adding specific groups. Otherwise B01D 67/0093 applies.

Details relating to filtering apparatus
Definition statement
This group covers:
  • Filters used for filtering particles out of a liquid.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This group does not cover:

Casings, housings or mounting for filters specially adapted for separating dispersed particles from gases or vapours

Multiple filter elements specially adapted for separating dispersed particles from gases or vapours

Sealing for filters specially adapted for separating dispersed particles from gases or vapours

Filter media structures for filters specially adapted for separating dispersed particles from gases or vapours

Filters specially adapted for separating dispersed particles from gases or vapours characterised by the position of the filter in relation to the gas stream

Filters adapted for separating dispersed particles from gages or vapours specially modified for specific uses

Applications of separation devices
Definition statement
This group covers:

This group relates to the application of the separation devices. It should be assigned if the application implicitly requires certain features (e.g. for separators installed in gullies, a shortcut between inlet and outlet for the fluid to be treated) and if it is deemed not necessary to assign a class corresponding to the technical field of application (E03F in the example before) or if a field of application is not reflected by a class (e.g. cleaning the polluted ambient air in cities).

Relationship between large subject matter areas

If there exists a field of application, a invention information symbol in that field should be assigned rather than an symbol in the present group.

Informative references
Attention is drawn to the following places, which may be of interest for search:

Attention is drawn to the following places, which may be of interest for search (especially for mechanical features):

Treating manure

Condensing atmospheric humidity

Air conditioning for animal housing

Devices used for fish ponds

Treatment of water for aquaria

Processing slaughtering residues

Clarifying non-alcoholic beverages

vacuum cleaners

Sedimentation devices for dental use

Sedimentation devices for medical purposes, body liquids

Filters making use of electricity or magnetism

Chemical or physical processes

Separation of particles from gases and vapours by electrostatic effect

Spraying devices using ultrasonic energy

Details of spraying plants

Paint sludge treatment

Methods or apparatus specially adapted for transmitting mechanical vibrations

Preventing escape of fumes from the area where they are produced

Removing chips from sawing machines

Removing chips from machine tools

Removing dust for machines for working stones

Ink filters for printers

Barges for collection of pollution from open water

Fluidising means for discharging large containers

Devices for separating the materials from propellant gas in material conveyors

Treatment of water, waste water, sewage, or sludge when structural details of general interest are disclosed.

Refining hydrocarbon oils by centrifugation

Dust removal from combustible gases containing carbon monoxide

Working-up lubricants

Clarifying alcoholic beverages

Apparatus for microbiology

Dust arrester for blast furnaces

Offtakes or separating apparatus for converter waste gases or dust in the manufacture of carbon-steel

After treatment in chemical coating in semiconductor industry

Details of domestic laundry driers

Treatment of exhaust gases along roads

Dispersing fog

E01H13/10

Cleaning or keeping clear the surface of open water; Apparatus therefore

Obtaining drinking water from atmospheric humidity

Kitchen sinks

Other installations or implements for operating sewer systems (cleaning, emptying, maintenance)

Sludge tanker

Treatment of water for swimming pools

Sedimentation devices used in drilling boreholes

Separation of well effluents

Purifying air before leaving the crankcase

Exhaust or silencing apparatus having means for purifying

Exhaust or silencing apparatus for marine propulsion

Combustion air cleaners

Exhaust ducts

Treating smoke and fumes using Washing fluids

Air conditioning

Removing cooking fumes

Direct contact trickle coolers

Removal of water droplets from fuel cell exhaust gases

Aspects relating to filtering material for liquid or gaseous fluids
Definition statement
This group covers:

Details of filtering material as put forward under the corresponding maingroup B01D 39/00

Informative references
Attention is drawn to the following places, which may be of interest for search:

Nanofibers

Adsorbents

Electret

Antibacterial additives

Fire retardant/Heat resistant properties

More than one layers in the filter material

Wound layers

Porosity, Pore size

L01D265/00 - L01D279/00
Details relating to gas filtering apparatus
Definition statement
This subclass/group covers:
  • Filters used for filtering particles out of a gas.
  • Only mechanical filtering is taking place, no reaction, no absorption or adsorption is involved
References relevant to classification in this group
This subclass/group does not cover:

Details for filters specially adapted for separating dispersed particles from liquids

Informative references
Attention is drawn to the following places, which may be of interest for search:

Filter materials

Air bags

Filtration in air conditioning

Filtration of exhaust gases from IC engines

Filtration in suction cleaners

Filtration of intake air for IC engines

Filtration in sterilisation

Details relating to membrane separation process operations and control
Special rules of classification within this group

These subgroups describes additional information and has to be used in accordance with the Rules for subgroups B01D 61/00 to B01D 71/00.

Details relating to membrane modules or apparatus
Special rules of classification within this group

These subgroups describes additional information and has to be used in accordance with the Rules for subgroups B01D 61/00 to B01D 71/00.

Details relating to the membrane module operation
Special rules of classification within this group

These subgroups describes additional information and has to be used in accordance with the Rules for subgroups B01D 61/00 to B01D 71/00.

Membrane module arrangements within a plant or an apparatus (membrane assemblies within one housing B01D 2319/00)
Special rules of classification within this group

These subgroups describes additional information and has to be used in accordance with the Rules for subgroups B01D 61/00 to B01D 71/00.

Membrane assemblies within one housing (module or elements arrangements within a plant or an apparatus B01D 2317/00)
Special rules of classification within this group

These subgroups describes additional information and has to be used in accordance with the Rules for subgroups B01D 61/00 to B01D 71/00.

Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
Special rules of classification within this group

These subgroups describes additional information and has to be used in accordance with the Rules for subgroups B01D 61/00 to B01D 71/00.

Details relating to membrane preparation
Special rules of classification within this group

These subgroups describes additional information and has to be used in accordance with the Rules for subgroups B01D 61/00 to B01D 71/00.

Details relating to properties of membranes
Special rules of classification within this group

These subgroups describes additional information and has to be used in accordance with the Rules for subgroups B01D 61/00 to B01D 71/00.

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Last Modified: 10/11/2013