CPC Definition - Subclass C25B

Last Updated Version: 2021.01
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 that act as electrolysers 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 or solutions, in the relevant places, e.g. A01K 63/00, C02F 1/46, C25B 15/08, C25D 21/16, C25F 7/02.

Cold fusion methods as such are classified in G21B 3/00, but electrodes and cells for 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

C02F 1/46

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

C07K 1/26

Inhibiting corrosion of metals by anodic or cathodic protection

C23F 13/00

Single crystal growth

C30B

Informative references

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

Methods or apparatus for disinfecting or sterilising

A61L 2/03, A61L 2/035

Making harmful compounds harmless by subjecting to electrochemical processes, electrodialysis

A62D 3/11

Gas separation, using electrochemical methods

B01D 53/326

Electrodialysis, electroosmosis

B01D 61/42

Separation, other than separation of solids, by electrophoresis

B01D 61/42

Catalysts

B01J

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

B01J 19/08

Separation of hydrogen or hydrogen containing gases from gaseous mixtures

C01B 3/50

Carbon masses

C01B 32/00, C04B 35/52

Electrochemical sensors

G01N 27/00

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

G21B 3/00

Electrochemical processes or apparatus for generating energy

H01M

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

H02S 40/44

Special rules of classification

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

Illustrative examples:

  • (1) Electrolysis of sodium chloride to develop chlorine gas that is collected as a product is covered by C25B.
  • (2) Electrolysis of water comprising sodium chloride to form chlorine / hypochlorite in solution for disinfection is not covered by C25B.

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

There are, of course, cases that 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

A monopolar electrode is connected to a power source and thus acts either as an anode or as a cathode.

Bipolar electrode

A bipolar electrode is a floating conductor in contact with an ionically conductive phase. It is a field electrode, positioned in an 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 that faces the cathode acts as an anode, and the side that faces the anode acts as a cathode.

Dimensionally-stable electrode

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

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

BPE

Bipolar electrode

MEA

Membrane Electrode Assembly

DSE

Dimensionally Stable Electrode

DSA

Dimensionally Stable Anode

GDE

Gas Diffusion Electrode

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

  • "diaphragm" and "separator" or "membrane"
Electrolytic production of inorganic compounds or non-metals
Definition statement

This place covers:

Electrolytic production of all those inorganic compounds or non-metals that do not fall within the scope of one of the subgroups of C25B 1/00.

Specific compounds like hydrogen, oxygen, silicon, ozone, alkali metal compounds, inorganic acid, per-compounds, etc. are classified in the subgroups of C25B 1/00, not in C25B 1/00.

Hydrogen or oxygen
Definition statement

This place covers:

Electrolytic production of hydrogen or oxygen.

References
Informative references

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

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

C01B 3/50

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

F02B 43/10

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)

F02M 25/12

Special rules of classification

Only the 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.

Ozone
Relationships with other classification places

Production of dissolved species for treating of water or waste water by electrochemical methods, cells and electrodes therefor is classified in C02F 1/467.

References
Informative references

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

Disinfecting / sterilising with "dental water"

A61C 1/0076

Halogens or compounds thereof
Relationships with other classification places

Production of dissolved species for treating of water or waste water by electrochemical methods, cells and electrodes therefor is classified in C02F 1/467.

Per-compounds
Definition statement

This place covers:

Electrolytic production of per-compounds (see Glossary of terms).

Relationships with other classification places

Treatment of water and waste water by electrochemical disinfection is classified in C02F 1/4672.

References
Informative references

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

Disinfecting / sterilising with "dental water"

A61C 1/0076

Glossary of terms

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

per-compounds

When an element can bond with oxygen in multiple ways to form different polyatomic ions (also called oxyanions), the prefixes "hypo-" and "per-" are used in conjunction with the suffixes "-ite" and "-ate" and a portion (x) of the name of the primary element to designate the oxyanion: (1) a "hypo-x-ite" ion has one fewer oxygen atom than (2) an "x-ite" ion, while an "x-ite" ion has one fewer oxygen atom than (3) an "x-ate" ion, and an "x-ate" ion has one fewer oxygen atom than (4) a "per-x-ate" ion (per-compound). For example, ClO- is hypochlorite, ClO2- is chlorite, ClO3- is chlorate, and ClO4- is perchlorate.

Photoelectrolysis
Definition statement

This place covers:

Photoelectrolysis process only.

Relationships with other classification places

Distinctions should be drawn among a (1) photoelectrolytic process (C25B 1/55), (2) cell with two electrodes, even without externally applied voltage (C25B 9/50), and (3) photolytic process or cell with a single electrode where the process is catalyzed by a substance producing photoelectrons (B01J 19/12 - B01J 19/129).

References
Informative references

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

Photocatalysts

B01J 35/004

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

H01G 9/20

Photoelectrochemical cells

H01M 14/005

Electrolytic production of organic compounds
Definition statement

This place covers:

Production of organic compounds by an electrolytic reaction.

References
Informative references

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

Electrolytic polymerisation

C08G 61/00

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

C10G 2/30

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

C10G 2/50

Electrocoating a substrate with an organic material

C25D 9/02

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

F02B 43/10

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)

F02M 25/12

Glossary of terms

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

Oxidation and reduction

A reaction that takes place directly at the organic molecule and involves an electron being lost (oxidation) or gained (reduction).

Coupling

A reaction that takes place directly at the organic molecule and does not involve oxidation or reduction, e.g. a Kolbe reaction.

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

This place covers:

Processes that generate electricity and produce a compound other than water, e.g. hydrogen peroxide.

Electrophoretic 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

C07K 1/26

Informative references

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

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

C25D 13/04

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

This place covers:

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

Relationships with other classification places

Devices for the electrolytic treatment of water or sewage are classified in C02F 1/46104.

References
Informative references

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

Electrolytic cells for electroplating

C25D 17/00

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

F02B 43/10

Reversible fuel cells

H01M 8/18

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).

Pressure cells
Definition statement

This place covers:

Cells subjected to pressure that exceeds ambient pressure, e.g. high-pressure water electrolysis system.

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).

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

DSE

Dimensionally Stable Electrode

DSA

Dimensionally Stable Anode

comprising ion-exchange membranes in or on which electrode material is embedded
Definition statement

This place covers:

Membrane-electrode assemblies (MEA).

Cells comprising movable electrodes, e.g. rotary electrodes; Assemblies of constructional parts thereof
Definition statement

This place covers:

Electrodes that move in space or around an axis, such as rotary electrodes.

Cells or assemblies of cells comprising electrodes made of particles; Assemblies of constructional parts thereof
Definition statement

This place covers:

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

Relationships with other classification places

Electrodes in particulate form for treatment of water, waste water or sewage are classified in C02F 1/46114.

{comprising fluidised bed electrodes}
Definition statement

This place covers:

Electrodes that comprise a bed of electrically conductive particles that are arranged such that they are in motion and temporarily contact each other and an electrical conductor (a net, a plate etc.) that provides connection to a power source.

{comprising static bed electrodes}
Definition statement

This place covers:

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

Synonyms and Keywords

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

  • " fixed bed electrode " and " static bed electrode "
Means for supplying current; Electrode connections; Electric inter-cell connections
Definition statement

This place covers:

Devices and connections that are monopolar.

References
Informative references

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

Bipolar electrodes

C25B 9/75

Electrical connections in fuel cells or storage batteries

H01M 8/02, H01M 50/50

Electrical connections in general

H01R

of the filter-press type
Glossary of terms

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

Filter-press type cells

Filter-press type cells generally consist of a stack of vertical frames that define electrolysis chambers in which electrodes are arranged vertically.

having 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:

Monopolar electrode

A monopolar electrode is connected to a power source and thus acts either as an anode or as a cathode.

Bipolar electrode

A bipolar electrode is a floating conductor in contact with an ionically conductive phase. It is a field electrode, positioned in an 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 that faces the cathode acts as an anode, and the side that faces the anode acts as a cathode.

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

BPE

Bipolar electrode

having diaphragms
Definition statement

This place covers:

Cells with a diaphragm, e.g. membrane or separator, which is a permeable barrier between electrodes.

Electrodes; Manufacture thereof not otherwise provided for
Definition statement

This place covers:

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

Relationships with other classification places

Electrodes for treatment of water or sewage are classified in C02F 1/46109.

References
Informative references

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

Photoelectrodes

B01J 35/004

Electrodes for electrowinning

C25C 7/02

Electrodes for electroplating

C25D 17/10

Electrodes for storage batteries

H01M 4/00

Electrodes for fuel cells

H01M 4/86

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.

Gas diffusion electrodes
References
Informative references

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

Gas diffusion electrodes for the generation of power

H01M 4/86, H01M 8/02

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

GDE

Gas diffusion electrodes

Carbon, e.g. diamond or graphene
Definition statement

This place covers:

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

Relationships with other classification places

Diamond electrodes used in treatment of water or waste water etc. are classified in C02F 1/46109 and C02F 2001/46133.

References
Informative references

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

Electrodes that comprise carbon either as the substrate or a coating

C25B 11/065

Diamond electrodes that comprise a diamond coating on a substrate

C25B 11/083

Carbon masses

C04B 35/52

Electrodes formed of electrocatalysts on a substrate or carrier
Glossary of terms

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

Substrate

The substrate forms the bulk of the electrode and includes oxide layers, which are particularly common on valve metals.

Coating

The coating includes all layers on the substrate, i.e. the coating is not exclusively the electrocatalytic layer, which is usually on top and in contact with the electrolyte. The coating also includes intermediate layers, such as oxide layers that are not inevitable, but intentionally formed on the substrate.

Diaphragms; Spacing elements
Definition statement

This place covers:

Structural material used to separate the electrodes of an electrolytic or electrophoretic cell to form two or more compartments and allow the flow of an electrolytic solution or the migration of particular ions while preventing the intermixing of the products formed at the surface of the electrodes.

References
Informative references

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

Membranes for separation processes

B01D 67/00- B01D 71/00

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

C25C 7/04

Membranes for fuel cells

H01M 8/0289

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, characterised by the electrolyte material

H01M 8/1016, H01M 2300/0088, H01M 2300/0065

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 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
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
Relationships with other classification places

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