Cooperative Patent Classification

CPC Definition - Subclass C25B

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Last Updated Version: 2016.11
ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F 13/00; single-crystal growth C30B)
Definition statement

This place covers:

Electrolytic production of inorganic compounds, of non-metals and of organic compounds

Electrogenerative processes, i.e. processes for producing compounds in which simultaneously electricity is generated

Electrophoretic production of compounds or non-metals

Cells or assemblies of cells, constructional parts of cells, assemblies of constructional parts, e.g. electrode-diaphragm assemblies, as long as they are used in or suitable for one of the above production methods

Electrodes, manufacture thereof not otherwise provided for, as long as they are used in or suitable for one of the above production methods

Diaphragms, spacing elements, as long as they are used in or suitable for one of the above production methods

Operating or servicing of cells, as long as this operating or servicing is part of one of the above production methods

Relationships with other classification places

The compounds of particular interest are also classified in the relevant classes, C01 (inorganic chemistry), C07 (organic chemistry), C07F (organo-metallic compounds ), and C08 (polymer chemistry ).

Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process provided for in class C25 are classified in group C23F 17/00.

Reversible fuel cells which act as electrolyzer, are classified in H01M 8/18.

Production of dissolved species for purposes of water or waste water treatment is classified in C02F 1/46 and subgroups.

The electrolytic or electrophoretic purification of materials is classified according to the nature of the liquid-material, e.g. water, electrolytes, processes solutions in the relevant places, e.g. A01K 63/00, C02F 1/46, C25B 15/08,C25D 21/16, C25F 7/02

Cold fusion method as such is classified in G21B 3/00 but electrodes and cells for the cold fusion are further classified in C25B.

An electrothermal treatment of ores or metallurgical products for obtaining metals or alloys is classified in C22B 4/00 and does not involve an electrolytic process.

Alloys as such, prepared by electrolytic methods are classified in C22C.

References
Limiting references

This place does not cover:

Treating of water, waste water etc. by electrochemical methods, cells and electrodes therefor

Separation or purification of peptides, e.g. of proteins, by electrophoresis

Inhibiting corrosion of metals by anodic or cathodic protection

Single crystal growth

Informative references

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

Methods or apparatus for disinfecting or sterilising

Making harmful compounds harmless by subjecting to electrochemical processes, electrodialysis

Electrodialysis, electroosmosis

B01D13/02, B01D 61/42

Gas separation, using electrochemical methods

Separation, other than separation of solids, by electrophoresis

Catalysts

Processes employing the direct application of electric energy (i.e. electrochemical processes); Apparatus therefor

Separation of hydrogen or hydrogen containing gases from gaseous mixtures

Carbon masses

Electrochemical sensors

Cold fusion, the method as such (however, cells and electrodes are classified in C25B)

Electrochemical processes or apparatus for generating energy

Semiconducting devices, photovoltaic cells as conversion devices, sources of energy (in particular for water electrolysis)

Special rules of classification

Classification in C25B is always according to the last place priority rule.

C25B concerns the production of compounds or non-metals, which includes separating the said products as such, or at least the possibility to separate them.

Illustrative example:

  • 1) Electrolysis of sodium chloride developing chlorine gas which is collected as a product is covered by C25B.
  • 2) Electrolysis of water comprising sodium chloride which forms chlorine / hypochlorite in solution for disinfection is not covered by C25B.

As a consequence, the electrolytic cells and parts of cells in case 1) are covered by C25B as well, while the electrolytic cells and parts of cells in case 2) are not.

There are of course cases which are covered by C25B and another subclass or subgroup.

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Monopolar electrode

Electrode which is connected to a power source and thus acts either as an anode or as a cathode

Bipolar electrode

Field electrode, i.e. an electrode which is positioned in the electrical field between a monopolar anode and a monopolar cathode without being itself connected to a power source. Through the action of the electrical field the side of the bipolar electrode which faces the cathode acts as an anode and the other side which faces the anode acts as a cathode

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

Diaphragm

Membrane

MEA

Membrane Electrode Assembly

DSE

Dimensionally Stable Electrode

DSA

Dimensionally Stable Anode

GDE

Gas Diffusion Electrode

Electrolytic production of inorganic compounds or non-metals
Definition statement

This place covers:

Electrolytic production of all those inorganic compounds or non metals which do not fall within the scope of one of the subgroups of C25B 1/00, e.g. electrolytic preparation of ammonia.

Specific compounds like hydrogen, oxygen, silicon, ozone, alkali metal compounds, inorganic acida, per-compounds, etc are classified in the subgroups of C25B 1/00.

{by photo-electrolysis with or without external current source}
Definition statement

This place covers:

Photo-electrolysis process only.

References
Limiting references

This place does not cover:

Photocatalysts

Light-sensitive devices, e.g. panels or arrays of photoelectrochemical cells

Photoelectrochemical cells

Special rules of classification

Distinction is to be done between a photoelectrolytic process or cell with two electrodes (even without externally applied voltage), and a photolytic process or cell with a single electrode where the process is catalyzed by a substance producing photoelectrons.

of hydrogen or oxygen
Definition statement

This place covers:

Electrolytic production of hydrogen or oxygen.

References
Limiting references

This place does not cover:

Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. hydrogen electrochemical pumps

Engines or plants characterised by use of other specific gases, e.g. oxyhydrogen (even when produced by an electrolytic cell)

Engine-pertinent apparatus for supplying combustion engine with gas, e.g. hydrogen or oxygen, the apparatus having means for preparing such gas (even when the means is an electrolytic cell)

Special rules of classification

Only details of the electrolytic production process present in the document are classified.

A simple reference to the presence of an electrolytic cell, or hydrogen produced by electrolysis, does not justify classification in C25B.

by electrolysis of water
Definition statement

This place covers:

Electrolysis of water with production of hydrogen and oxygen from water at the anode and cathode even when this water comprises an electroconductive additive, such as a hydroxide or an acid.

Steam electrolysis is also covered.

in diaphragm cells
Definition statement

This place covers:

Electrolytic production of hydrogen or oxygen by electrolysis of water using diaphragm cells, the diaphragm being a barrier between electrodes, e.g. membrane,separator.

References
Informative references

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

Reversible fuel cells

in pressure cells
Definition statement

This place covers:

Electrolytic production of hydrogen or oxygen by electrolysis of water using cells under pressure, e.g. high pressure water electrolysis system

References
Informative references

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

Reversible fuel cells

of ozone
References
Limiting references

This place does not cover:

Disinfecting / sterilising using electric current or electrolysis

A02L/03, A02L/03E

Disinfecting / sterilising with "dental water"

Production of dissolved species for treating of water, waste water etc. by electrochemical methods, cells and electrodes therefor

of halogens or compounds thereof
References
Limiting references

This place does not cover:

Production of dissolved species for treating of water, waste water etc. by electrochemical methods, cells and electrodes therefor

of per-compounds
Definition statement

This place covers:

Electrolytic production of per-compounds (per-compounds being defined in the glossary of terms).

References
Limiting references

This place does not cover:

Disinfecting / sterilising using electric current or electrolysis

A02L/03, A02L/03E

Disinfecting / sterilising with "dental water"

Treatment of water and waste water by electrochemical disinfection

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

per-compounds

compounds with oxyanions. When an element fors 4 oxyanions, the hypo and per prefexies are used in conjuntion with -ite or -ate suffixes, "per" being used to indicate more oxygen

Electrolytic production of organic compounds
Definition statement

This place covers:

Production of organic compounds by an electrolytic reaction.

References
Limiting references

This place does not cover:

Electrolytic polymerization

Production of hydrocarbons from hydrogen (even when produced by an electrolytic cell) and carbon monoxide

Production of hydrocarbons from hydrogen (even when produced by an electrolytic cell) and carbon dioxide

Electrocoating a substrate with an organic material

Engines or plants characterised by use of other specific gases, e.g. oxyhydrogen (even when produced by an electrolytic cell)

Engine-pertinent apparatus for supplying combustion engine with gas, e.g. hydrocarbon gas, the apparatus having means for preparing such gas (even when the means is an electrolytic cell)

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Oxidation and reduction

oxidation or reduction directly at the organic molecule

Coupling

reaction without oxidation or reduction directly at the organic molecule, e.g. a Kolbe reaction

Electrogenerative processes, i.e. processes for producing compounds in which simultaneously electricity is generated
Definition statement

This place covers:

Processes when electricity is generated while a compound is produced other than water, e.g. hydrogen peroxide

Electrophorectic production of compounds or non-metals (separation or purification of peptides, e.g. of proteins, by electrophoresis C07K 1/26)
Definition statement

This place covers:

Production of compounds or non-metals where the process includes a step of reduction or oxidation of the material from which the compound or non-metals is formed, e.g. formation of a polymer.

References
Limiting references

This place does not cover:

Separation or purification of peptides, e.g. of proteins, by electrophoresis

Electrocoating, when the coating is only deposited and not produced by an electrolytic reaction

Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies
Definition statement

This place covers:

Cells, assembly of cells, assemblies of constructional parts used for the electrolytic production processes which are defined in other subgroups of C25B.

References
Limiting references

This place does not cover:

Devices for the electrolytic treatment of water or sewage

The combination of an electrolytic cell with a combustor to improve combustion.

Informative references

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

Electrolytic cells for electroplating

Reversible fuel cells

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Grouping of such cells into batteries

arranging plural cells such that they form a pile (not to form a storage battery)

Devices for current supply (electrical connections in general H01R); Electrode connections; Electric inter-cell connections
Definition statement

This place covers:

Devices and connections which are monopolar.

References
Limiting references

This place does not cover:

Bipolar plates for electrolytic cells

Informative references

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

Electrical connections in fuel cells or storage batteries

Electrical connections in general

Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
Definition statement

This place covers:

Cells and their construction comprising electrodes that are not sacrificial.

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Dimensionally-stable electrode

an electrode that is not intended to dissolve upon electrolysis (not a sacrificial electrode)

{including bipolar electrodes}
Definition statement

This place covers:

Cells and their construction comprising bipolar electrodes that are not sacrificial

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Bipolar electrode

Field electrode, i.e. an electrode which is positioned in the electrical field between a monopolar anode and a monopolar cathode without being itself connected to a power source. Through the action of the electrical field the side of the bipolar electrode which faces the cathode acts as an anode and the other side which faces the anode acts as a cathode

including an ion-exchange membrane in or on which electrode material is embedded
Definition statement

This place covers:

Membrane-electrode assemblies (MEA).

Cells or assemblies of cells comprising at least one movable electrode, e.g. rotary electrodes; Assemblies of constructional parts thereof
Definition statement

This place covers:

Movable electrode, be it electrodes that move in space or electrodes that move around an axis, such as rotary electrodes.

Cells or assemblies of cells comprising at least one electrode made of particles; Assemblies of constructional parts thereof
Definition statement

This place covers:

Electrodes comprising a bed of electrically conductive particles which are arranged such that they at least temporarily touch each other and an electrical conductor (a net, a plate etc.) which provides connection to a power source.

References
Limiting references

This place does not cover:

Electrodes in particulate form for treatment of water or waste water or sewage

{comprising fluidised bed electrodes}
Definition statement

This place covers:

Electrodes that comprise a bed of electrically conductive particles which are in motion, such that they only temporarily touch each other and the electrical conductor.

{comprising static bed electrodes}
Definition statement

This place covers:

Electrodes that comprise a bed of electrically conductive particles which rest, such that they continually touch each other and the electrical conductor.

Synonyms and Keywords

In patent documents, the following words/expressions are often used as synonyms:

  • " fixed bed electrode " and " static bed electrode "
Assemblies comprising a plurality of cells ({C25B 9/005 takes precedence}; assemblies of cells with movable electrodes C25B 9/12; assemblies of cells with electrodes made of particles C25B 9/16)
References
Limiting references

This place does not cover:

Assemblies of cells with movable electrodes

Assemblies of cells with electrodes made of particles

Special rules of classification

C25B 9/005 takes precedence.

of the filter-press type
Definition statement

This place covers:

Stack of a plurality of cells in series, as in a filter press, e.g. electrodes are arranged vertically in a stack of vertical frames defining the electrolysis chamber(s)

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Filter-press type cells

generally consist of a stack of vertical frames which define electrolysis chambers in which electrodes are arranged vertically

{with bipolar electrodes}
Definition statement

This place covers:

Stacks of a plurality of cells with bipolar electrodes, as in a filter press.

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Bipolar electrode

field electrode, i.e. an electrode which is positioned in the electrical field between a monopolar anode and a monopolar cathode without being itself connected to a power source. Through the action of the electrical field the side of the bipolar electrode which faces the cathode acts as an anode and the other side which faces the anode acts as a cathode

Electrodes; Manufacture thereof not otherwise provided for
Definition statement

This place covers:

Electrodes used for the electrolytic or electrochemical production processes which are defined somewhere in C25B.

References
Limiting references

This place does not cover:

Electrodes for treatment of water or sewage

Informative references

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

Photoelectrodes

Electrodes for electrowinning

Electrodes for electroplating

Electrodes for storage batteries

Electrodes for fuel cells

Special rules of classification

The electrodes corresponding to IPC C25B11/06 - C25B11/10 are classified in C25B 11/04.

characterised by shape or form
Definition statement

This place covers:

Special forms of electrodes, such a Venetian blinds, expandable electrodes.

perforated or foraminous
Definition statement

This place covers:

Perforated or foraminous structures, e.g. expandable metal.

{Porous electrodes}
References
Limiting references

This place does not cover:

Gas diffusion electrodes (GDE)

{of electrodes having a substrate and a coating}
Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Substrate

the bulk of the electrode, also including inevitable oxide layers which are present in particular on the valve metals

Coating

all layers on the substrate, i.e. not only the electrocatalytic coating (which is usually on top and in contact with the electrolyte), but also intermediate layers (also those oxide layers which are not inevitable but formed on purpose on the substrate)

Electrodes based on carbon (carbon masses in general C04B 35/52 ){(C25B 11/0405 takes precedence)}
Definition statement

This place covers:

Electrodes which have a carbon-based structure, e.g. carbon cloth.

Diamond electrodes which are completely made of diamond, i.e. which are not a substrate with a diamond coating, are also covered

References
Limiting references

This place does not cover:

Electrodes which comprise carbon either as the substrate or a coating

Diamond electrodes which comprise a diamond coating on a substrate

Diamond electrodes used in treatment of water, waste water etc.

Informative references

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

Carbon masses

Electrodes based on manganese dioxide or lead dioxide {(C25B 11/0405 takes precedence)}
References
Limiting references

This place does not cover:

Electrodes which comprise manganese dioxide or lead dioxide either as the substrate or a coating

Mercury or amalgam electrodes {(C25B 11/0405 takes precedence)}
References
Limiting references

This place does not cover:

Electrodes which comprise mercury or amalgam either as the substrate or a coating

Diaphragms; Spacing elements
Definition statement

This place covers:

Structural material used to separate the electrodes of an electrolytic or electrophoretic cell, thereby forming two or more compartments, allowing the flow of an electrolytic solution or the migration of particular ions, but preventing the complete intermising of the two solutions of the migration of all kinds of ions.

References
Informative references

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

Membranes for separation processes

Membranes for electrolytic production, recovery or refining of metals or alloys

Membranes for fuel cells

Synonyms and Keywords

In patent documents, the following words/expressions are often used as synonyms:

  • "diaphragm " and " membrane"
characterised by the material
References
Informative references

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

Solid state electrolytes for fuel cells, characterized by the electrolyte material

based on organic materials
Relationships with other classification places

Organic polymer membranes when the emphasis is on the polymer electrolyte compound are classified in C08J 5/22, and in H01M 8/1018 or H01M 2300/0082 if the polymer electrolyte compound is used in fuel cells.

Operating or servicing of cells
Definition statement

This place covers:

Operating or servicing of cells when generally applied to a cell or in a process of C25B.

When related to a specific process only, the operating or servicing is classified with the process, e.g. decomposition of amalgam which is process-related and therefore classified in C25B 1/42.

Process control or regulation (controlling or regulating in general G05)
References
Informative references

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

Controlling or regulating in general

G05

Regulation of the inter-electrode distance (electro-machining B23P)
Relationships with other classification places

Regulation of the inter-electrode distance in electrochemical machining, electrolytic grinding and electro-erosion is classified in B23H.