reach the classification of the 'services', click here.
The classification of the 'products' distributed in 8 principal sections (numbered from A to H).
While clicking on one or the other of the titles of these sections you will reach the details of the selected section :
SECTION A - HUMAN NECESSITIES
SECTION B - PERFORMING OPERATIONS; TRANSPORTING
SECTION C - CHEMISTRY; METALLURGY
SECTION D - TEXTILES; PAPER
SECTION E - FIXED CONSTRUCTIONS
SECTION F - MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
SECTION G - PHYSICS
SECTION H - ELECTRICITY
SECTION A - HUMAN NECESSITIES
A 01 - AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
A 21 - A 21 - BAKING; EDIBLE DOUGHS
A 22 - BUTCHERING; MEAT TREATMENT; PROCESSING POULTRY OR FISH
A 23 - FOODS OR FOODSTUFFS; THEIR TREATMENT, NOT COVERED BY OTHER CLASSES
A 24 - TOBACCO; CIGARS; CIGARETTES; SMOKERS' REQUISITES
PERSONAL OR DOMESTIC ARTICLES
A 41 - WEARING APPAREL
A 42 - HEADWEAR
A 43 - FOOTWEAR
A 44 - HABERDASHERY; JEWELLERY
A 45 - HAND OR TRAVELLING ARTICLES
A 46 - BRUSHWARE
A 47 - FURNITURE (arrangements of seats for, or adaptation of seats to, vehicles B60N); DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL (ladders E06C)
A 61 - MEDICAL OR VETERINARY SCIENCE; HYGIENE
A 62 - LIFE-SAVING; FIRE-FIGHTING (ladders E06C)
A 63 - SPORTS; GAMES; AMUSEMENTS
SECTION B - PERFORMING OPERATIONS; TRANSPORTING
Notes (The following notes are meant to assist in the use of this part of the classification scheme; they must not be read as modifying in any way the elaborations).
(1) In this sub-section, the separation of different materials, e.g. of different matter, size, or state, is predominantly found in the following subclasses : B01D, B03B, B03C, B03D, B04B, B04C, B07B, B07C.
(2) The classifying characteristics of these subclasses are:
(i) the physical state of the matter to be separated;
(ii) the principle of the process used;
(iii) particular kinds of apparatus.
The first of these characteristics involves six different aspects, assembled in three groups:
(a) liquid/liquid or liquid/gas and gas/gas;
(b) solid/liquid or solid/gas;
(3) These subclasses are to be used according to the following general rules:
- B01D is the most general class as far as separation other than solids from solids is concerned.
- Apparatus for separating solids from solids are covered by B03B when the process concerned is regarded as the equivalent of "washing" in the sense of the mining art, even if such apparatus is a pneumatic one, especially pneumatic tables or jigs.
Screens per se are not covered by this subclass but are classified in B07B, even if they are being used in a wet process.
All other apparatus for the separation of solids from solids according to dry methods are classified in B07B.
- If the separation takes place as a result of the detection or measurement of some feature of the material or articles to be sorted it is classified in B07C.
It should also be noted that the separation of isotopes of the same chemical element is covered by B01D 59/00, whatever process or apparatus is employed.
B 01 - PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL (furnaces, kilns, ovens, retorts, in general F27)
B 02 - CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
B 03 - SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS (separating isotopes B01D 59/00; crushing or disintegrating B02C; centrifuges or vortex apparatus for carrying out physical processes B04) 
B 04 - CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
B 05 - SPRAYING OR ATOMISING IN GENERAL; APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL (domestic cleaning A47L; cleaning in general by methods essentially involving the use or presence of liquid B08B 3/00; sand-blasting B24C; coating of articles during shaping of substances in a plastic state B29C 39/10, B29C 39/18, B29C 41/20, B29C 41/30, B29C 43/18, B29C 43/28, B29C 45/14, B29C 47/02; for further classification of forming layered products, see B32B; printing, copying B41; conveying articles or workpieces through baths of liquid B65G, e.g. B65G 49/02; handling webs or filaments in general B65H; surface treatment of glass by coating C03C 17/00, C03C 25/10; coating or impregnation of mortars, concrete, stone or ceramics C04B 41/45, C04B 41/61, C04B 41/81; paints, varnishes, lacquers C09D; enamelling of metals, applying a vitreous layer to metals, chemical cleaning or de-greasing of metallic objects C23; electroplating C25D; treating of textile materials by liquids, gases or vapours D06B; laundering D06F; treating roads E01C; apparatus or processes for the preparation or treatment of photosensitive materials G03; apparatus or processes, restricted to a purpose fully provided for in a single other class, see the relevant class covering the purpose) 
B 06 - GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
B 07 - SEPARATING SOLIDS FROM SOLIDS; SORTING (separation in general B01D; wet separating processes, sorting by processes using fluent material in the same way as liquid B03; using liquids B03B, B03D; sorting by magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high voltage electric fields B03C; centrifuges or vortex apparatus for carrying out physical processes B04; sorting peculiar to particular materials or articles and provided for in other classes, see the relevant classes)
B 08 - CLEANING
B 09 - DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL (treatment of waste water, sewage or sludge C02F; treating radioactively contaminated solids G21F 9/28) [3,6]
B 21 - MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (casting, powder metallurgy B22; shearing B23D; working of metal by the action of a high concentration of electric current B23H; soldering, welding, flame-cutting B23K; other working of metal B23P; punching sheet material in general B26F; processes for changing of physical properties of metals C21D, C22F; electroforming C25D 1/00)
B 22 - CASTING; POWDER METALLURGY
B 23 - MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR (punching, perforating, making articles by processing sheet metal, tubes, or profiles B21D; wire-working B21F; making pins, needles, or nails B21G; making chains B21L; grinding B24)
B 24 - GRINDING; POLISHING
B 25 - HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; HANDLES FOR HAND IMPLEMENTS; WORKSHOP EQUIPMENT; MANIPULATORS
B 26 - HAND CUTTING TOOLS; CUTTING; SEVERING
B 27 - WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
B 28 - WORKING CEMENT, CLAY, OR STONE
B 29 - WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL (processing doughs A21C; working chocolate A23G; casting of metals B22; working cement, clay B28; chemical aspects, see section C, particularly C08; working glass C03B; candle making C11C 5/02; making soap C11D 13/00; manufacture of artificial filaments, threads, fibres, bristles or ribbons D01D, D01F; manufacture of articles from cellulosic fibrous suspensions or from papier-mâche D21J)
B 30 - PRESSES
B 31 - MAKING PAPER ARTICLES; WORKING PAPER (making layered products not composed wholly of paper or cardboard B32B; handling thin material, e.g. sheets, webs, B65H)
B 32 - LAYERED PRODUCTS
B 41 - PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS (reproduction or duplication of pictures or patterns by scanning and converting into electrical signals H04N) 
B 42 - BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
B 43 - WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
B 44 - DECORATIVE ARTS
B 60 - VEHICLES IN GENERAL
B 61 - RAILWAYS
B 62 - LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
B 63 - SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
B 64 - AIRCRAFT; AVIATION; COSMONAUTICS
B 65 - CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
B 66 - HOISTING; LIFTING; HAULING
B 67 - OPENING OR CLOSING BOTTLES, JARS OR SIMILAR CONTAINERS; LIQUID HANDLING (nozzles in general B05B; packaging liquids B65B, e.g. B65B 3/00; pumps in general F04; siphons F04F 10/00; valves F16K; handling liquefied gases F17C)
B 68 - SADDLERY; UPHOLSTERY
MICRO-STRUCTURAL TECHNOLOGY; NANO-TECHNOLOGY 
B 81 - MICRO-STRUCTURAL TECHNOLOGY 
B 82 - NANO-TECHNOLOGY
SECTION C - CHEMISTRY; METALLURGY
Note : In section C, the definitions of groups of chemical elements are as follows :
- Alkali metals: Li, Na, K, Rb, Cs, Fr
- Alkaline earth metals: Ca, Sr, Ba, Ra
- Lanthanides: elements with atomic numbers 57 to 71 inclusive
- Rare earths: Sc, Y, Lanthanides
- Actinides: elements with atomic numbers 89 to 103 inclusive
- Refractory metals: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W
- Halogens: F, Cl, Br, I, At
- Noble gases: He, Ne, Ar, Kr, Xe, Rn
- Platinum group: Os, Ir, Pt, Ru, Rh, Pd
- Noble metals: Ag, Au, Platinum group
- Light metals: alkali metals, alkaline earth metals, Be, Al, Mg
- Heavy metals: metals other than light metals
- Iron group: Fe, Co, Ni
- Non-metals: H, B, C, Si, N, P, O, S, Se, Te, noble gases, halogens
- Metals: elements other than non-metals
- Transition elements: elements with atomic numbers 21 to 30 inclusive, 39 to 48 inclusive, 57 to 80 inclusive, 89 upwards
Notes : The following notes are meant to assist in the use of this part of the classification scheme. They must not be read as modifying in any way the elaborations.
(1) Section C covers:
(a) pure chemistry, which covers inorganic compounds, organic compounds, macromolecular compounds, and their methods of preparation;
(b) applied chemistry, which covers compositions containing the above compounds, such as: glass, ceramics, fertilisers, plastics compositions, paints, products of the petroleum industry. It also covers certain compositions on account of their having particular properties rendering them suitable for certain purposes, as in the case of explosives, dyestuffs, adhesives, lubricants, and detergents;
(c) certain marginal industries, such as the manufacture of coke and of solid or gaseous fuels, the production and refining of oils, fats and waxes, the fermentation industry (e.g., brewing and wine-making), the sugar industry;
(d) certain operations or treatments, which are either purely mechanical, e.g., the mechanical treatment of leather and skins, or partly mechanical, e.g., the treatment of water or the prevention of corrosion in general;
(e) metallurgy, ferrous or non-ferrous alloys.
(a) In the case of operations, treatments, products or articles having both a chemical and a non-chemical part or aspect, the general rule is that the chemical part or aspect is covered by section C.
(b) In some of these cases, the chemical part or aspect brings with it a non-chemical one, even though purely mechanical, because this latter aspect either is essential to the operation or treatment or constitutes an important element thereof. It has seemed, in fact, more logical not to dissociate the different parts or aspects of a coherent whole. This is the case for applied chemistry and for the industries, operations and treatments mentioned in Notes (1)(c), (d) and (e). For example, furnaces peculiar to the manufacture of glass are covered by class C03 and not by class F27.
(c) There are, however, some exceptions in which the mechanical (or non-chemical) aspect carries with it the chemical aspect, for example:
- Certain extractive processes, in subclass A61K;
- The chemical purification of air, in subclass A61L;
- Chemical methods of fire-fighting, in subclass A62D;
- Chemical processes and apparatus, in class B01;
- Impregnation of wood, in subclass B27K;
- Chemical methods of analysis or testing, in subclass G01N;
- Photographic materials and processes, in class G03, and, generally, the chemical treatment of textiles and the production of cellulose or paper, in section D.
(d) In still other cases, the pure chemical aspect is covered by section C and the applied chemical aspect by another section, such as A, B or F, e.g., the use of a substance or composition for:
- treatment of plants or animals, covered by subclass A01N;
- foodstuffs, covered by class A23;
- ammunition or explosives, covered by class F42.
(e) When the chemical and mechanical aspects are so closely interlocked that a neat and simple division is not possible, or when certain mechanical processes follow as a natural or logical continuation of a chemical treatment, section C may cover, in addition to the chemical aspect, a part only of the mechanical aspect, e.g., after-treatment of artificial stone, covered by class C 04. In this latter case, a note or a reference is usually given to make the position clear, even if sometimes the division is rather arbitrary.
C 01 - INORGANIC CHEMISTRY (processing powders of inorganic compounds preparatory to the manufacturing of ceramic products C04B 35/00; fermentation or enzyme-using processes for the preparation of elements or inorganic compounds except carbon dioxide C12P 3/00; obtaining metal compounds from mixtures, e.g. ores, which are intermediate compounds in a metallurgical process for obtaining a free metal C21B, C22B; production of non-metallic elements or inorganic compounds by electrolysis or electrophoresis C25B)
C 02 - TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (settling tanks, filtering, e.g. sand filters or screening devices, B01D)
C 03 - GLASS; MINERAL OR SLAG WOOL
C 04 - CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES (alloys based on refractory metals C22C) 
C 05 - FERTILISERS; MANUFACTURE THEREOF (processes or devices for granulating materials, in general B01J 2/00; soil-conditioning or soil-stabilising materials C09K 17/00) 
C 06 - EXPLOSIVES; MATCHES
C 07 - ORGANIC CHEMISTRY (such compounds as the oxides, sulfides, or oxysulfides of carbon, cyanogen, phosgene, hydrocyanic acid or salts thereof C01; products obtained from layered base-exchange silicates by ion-exchange with organic compounds such as ammonium, phosphonium or sulfonium compounds or by intercalation of organic compounds C01B 33/44; macromolecular compounds C08; dyes C09; fermentation products C12; fermentation or enzyme-using processes to synthesise a desired chemical compound or composition or to separate optical isomers from a racemic mixture C12P; production of organic compounds by electrolysis or electrophoresis C25B 3/00, C25B 7/00) 
C 08 - ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON (manufacture or treatment of artificial threads, fibres, bristles or ribbons D01)
C 09 - DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; MISCELLANEOUS COMPOSITIONS; MISCELLANEOUS APPLICATIONS OF MATERIALS
C 10 - PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
C 11 - ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES (edible oil or fat compositions A23
C 12 - BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
C 13 - SUGAR INDUSTRY (polysaccharides, e.g. starch, derivatives thereof C08B; malt C12C) 
C 14 - SKINS; HIDES; PELTS; LEATHER
C 21 - METALLURGY OF IRON
C 22 - METALLURGY (of iron C21); FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS (general methods or devices for heat treatment of ferrous or non-ferrous metals or alloys C21D; production of metals by electrolysis or electrophoresis C25)
C 23 - COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL (by metallising textiles D06M 11/83; decorating textiles by locally metallising D06Q 1/04); CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (for specific applications, see the relevant places, e.g. for manufacturing resistors H01C 17/06); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL (treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D, C25F) 
C 25 - ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR (electrodialysis, electro-osmosis, separation of liquids by electricity B01D; working of metal by the action of a high concentration of electric current B23H; treatment of water, waste water or sewage by electrochemical methods C02F 1/46; surface treatment of metallic material or coating involving at least one process provided for in class C23 and at least one process covered by this class C23C 28/00, C23F 17/00; anodic or cathodic protection C23F; single-crystal growth C30B; metallising textiles D06M 11/83; decorating textiles by locally metallising D06Q 1/04; electrochemical methods of analysis G01N; electrochemical measuring, indicating or recording devices G01R; electrolytic circuit elements, e.g. capacitors, H01G; electrochemical current or voltage generators H01M) 
C 30 - CRYSTAL GROWTH (separation by crystallisation in general B01D 9/00) 
SECTION D - TEXTILES, PAPER
TEXTILES OR FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
D 01 - NATURAL OR ARTIFICIAL THREADS OR FIBRES; SPINNING (metal threads B21; fibres or filaments of softened glass, minerals, or slag C03B 37/00; yarns D02)
D 02 - YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
D 03 - WEAVING
D 04 - BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
D 05 - SEWING; EMBROIDERING; TUFTING
D 06 - TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
D 07 - ROPES; CABLES OTHER THAN ELECTRIC
D 21 - PAPER-MAKING; PRODUCTION OF CELLULOSE
SECTION E - FIXED CONSTRUCTIONS
E 01 - CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES (of tunnels E21D)
E 02 - HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL-SHIFTING
E 03 - WATER SUPPLY; SEWERAGE
E 04 - BUILDING (layered materials, layered products in general B32B)
E 05 - LOCKS; KEYS; WINDOW OR DOOR FITTINGS; SAFES
E 06 - DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS, IN GENERAL; LADDERS
EARTH OR ROCK DRILLING; MINING
E 21 - EARTH OR ROCK DRILLING; MINING
SECTION F - - MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
ENGINES OR PUMPS
Notes : Guide to the use of this subsection (classes F01 to F04)
The following notes are meant to assist in the use of this part of the classification scheme.
(1) In this subsection, subclasses or groups designating "engines" or "pumps" cover methods of operating the same, unless otherwise specifically provided for.
(2) In this subsection, the following terms or expressions are used with the meanings indicated:
- "engine" means a device for continuously converting fluid energy into mechanical power. Thus, this term includes, for example, steam piston engines or steam turbines, per se, or internal-combustion piston engines, but it excludes single-stroke devices. "Engine" also includes the fluid-motive portion of a meter unless such portion is particularly adapted for use in a meter;
- "pump" means a device for continuously raising, forcing, compressing, or exhausting fluid by mechanical or other means. Thus, this term includes fans or blowers;
- "machine" means a device which could equally be an engine and a pump, and not a device which is restricted to an engine or one which is restricted to a pump;
- "positive displacement" means the way the energy of a working fluid is transformed into mechanical energy, in which variations of volume created by the working fluid in a working chamber produce equivalent displacements of the mechanical member transmitting the energy, the dynamic effect of the fluid being of minor importance, and vice versa;
- "non-positive displacement" means the way the energy of a working fluid is transformed into mechanical energy, by transformation of the energy of the working fluid into kinetic energy, and vice versa;
- "oscillating-piston machine" means a positive-displacement machine in which a fluid-engaging work-transmitting member oscillates. This definition applies also to engines and pumps;
- "rotary-piston machine" means a positive-displacement machine in which a fluid-engaging work-transmitting member rotates about a fixed axis or about an axis moving along a circular or similar orbit. This definition applies also to engines and pumps;
- "rotary piston" means the work-transmitting member of a rotary-piston machine and may be of any suitable form, e.g., like a toothed gear;
- "cooperating members" means the "oscillating piston" or "rotary piston" and another member, e.g., the working-chamber wall, which assists in the driving or pumping action;
- "movement of the co-operating members" is to be interpreted as relative, so that one of the "co-operating members" may be stationary, even though reference may be made to its rotational axis, or both may move;
- "teeth or tooth equivalents" include lobes, projections or abutments;
- "internal-axis type" means that the rotational axes of the inner and outer co-operating members remain at all times within the outer member, e.g., in a similar manner to that of a pinion meshing with the internal teeth of a ring gear;
- "free piston" means a piston of which the length of stroke is not defined by any member driven thereby;
- "cylinders" means positive-displacement working chambers in general. Thus, this term is not restricted to cylinders of circular cross-section;
- "main shaft" means the shaft which converts reciprocating piston motion into rotary motion or vice versa;
- "plant" means an engine together with such additional apparatus as is necessary to run the engine. For example, a steam engine plant includes a steam engine and means for generating the steam;
- "working fluid" means the driven fluid in a pump and the driving fluid in an engine. The working fluid may be in a gaseous state, i.e., compressible, or liquid. In the former case coexistence of two states is possible;
- "steam" includes condensable vapours in general, and "special vapour" is used when steam is excluded;
- "reaction type" as applied to non-positive-displacement machines or engines means machines or engines in which pressure/velocity transformation takes place wholly or partly in the rotor. Machines or engines with no, or only slight, pressure/velocity transformation in the rotor are called "impulse type".
(3) In this subsection:
- cyclically operating valves, lubricating, gas-flow silencers or exhaust apparatus, or cooling are classified in subclasses F01L, F01M, F01N, F01P irrespective of their stated application, unless their classifying features are peculiar to their application, in which case they are classified only in the relevant subclass of classes F01 to F04;
- lubricating, gas-flow silencers or exhaust apparatus, or cooling of machines or engines are classified in subclasses F01M, F01N, F01P except for those peculiar to steam engines which are classified in subclass F01B.
(4) For use of this subsection with a good understanding, it is essential to remember, so far as subclasses F01B, F01C, F01D, F03B, and F04B, F04C, F04D, which form its skeleton, are concerned:
- the principle which resides in their elaboration,
- the classifying characteristics which they call for, and
- their complementarity.
This concerns essentially the subclasses listed above. Other subclasses, notably those of class F02, which cover better-defined matter, are not considered here.
Each subclass covers fundamentally a genus of apparatus (engine or pump) and by extension covers equally "machines" of the same kind. Two different subjects, one having a more general character than the other, are thus covered by the same subclass.
Subclasses F01B, F03B, F04B, beyond the two subjects which they cover, have further a character of generality in relation to other subclasses concerning the different species of apparatus in the genus concerned.
This generality applies as well for the two subjects dealt with, without these always being in relation to the same subclasses.
Thus, subclass F03B, in its part dealing with "machines", should be considered as being the general class relating to subclasses F04B, F04C, and in its part dealing with "engines" as being general in relation to subclass F03C.
The principal classifying characteristic of the subclass is that of genera of apparatus, of which there are three possible: Machines; engines; pumps.
As stated above, "machines" are always associated with one of the other two genera. These main genera are subdivided according to the general principles of operation of the apparatus:
Positive displacement; non-positive displacement.
The positive displacement apparatus are further subdivided according to the ways of putting into effect the principle of operation, that is, to the kind of apparatus:
Simple reciprocating piston; rotary or oscillating piston; other kind.
Another classifying characteristic is that of the working fluid, in respect of which three kinds of apparatus are possible, namely: Liquid and elastic fluid; elastic fluid; liquid.
F 01 - MACHINES OR ENGINES IN GENERAL (combustion engines F02; machines for liquids F03, F04); ENGINE PLANTS IN GENERAL; STEAM ENGINES
F 02 - COMBUSTION ENGINES (cyclically operating valves therefor, lubricating, exhausting, or silencing engines F01); HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
F 03 - MACHINES OR ENGINES FOR LIQUIDS (for liquids and elastic fluids F01; positive-displacement machines for liquids F04); WIND, SPRING, WEIGHT, OR MISCELLANEOUS MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
F 04 - POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS (portable fire extinguishers with manually-operated pumps A62C 11/00, with power-driven pumps A62C 25/00; charging or scavenging combustion engines by pumps F02B; engine fuel-injection pumps F02M; ion pumps H01J 41/12; electrodynamic pumps H02K 44/02)
ENGINEERING IN GENERAL
F 15 - FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
F 16 - ENGINEERING ELEMENTS OR UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
F 17 - STORING OR DISTRIBUTING GASES OR LIQUIDS (water supply E03B)
F 21 - F 21 - LIGHTING (electric aspects or elements, see section H, e.g. electric light sources H01J, H01K, H05B)
F 22 - STEAM GENERATION (chemical or physical apparatus for generating gases B01J; chemical generation of gas, e.g. under pressure, Section C; removal of combustion products or residues, e.g. cleaning of the combustion contaminated surfaces of tubes of boilers, F23J; generating combustion products of high pressure or high velocity F23R; water heaters not for steam generation F24H, F28; cleaning of internal or external surfaces of heat-transfer conduits, e.g. water tubes of boilers, F28G)
F 23 - COMBUSTION APPARATUS; COMBUSTION PROCESSES
F 24 - HEATING; RANGES; VENTILATING (protecting plants by heating in gardens, orchards, or forests A01G 13/06; baking ovens and apparatus A21B; cooking devices other than ranges A47J; forging B21J, B21K; specially adapted for vehicles, see the relevant subclasses of classes B60 to B64; combustion apparatus in general F23; drying F26B; ovens in general F27; electric heating elements or arrangements H05B)
F 25 - REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION OR SOLIDIFICATION OF GASES
F 26 - DRYING
F 27 - FURNACES; KILNS; OVENS; RETORTS (specially adapted for a purpose covered by a single other class and specifically mentioned in that class, see the class in question, e.g. bakery ovens A21B, glass melting furnaces C03B, coke or gas-making apparatus C10B, C10J, apparatus for cracking hydrocarbons C10G, blast furnaces C21B, converters for making steel C21C, furnaces for heat treatment of metal C21D; furnaces for electroslag or arc remelting of metals C22B 9/00; enamelling ovens C23D; combustion apparatus F23; electric heating H05B) 
F 28 - HEAT EXCHANGE IN GENERAL (heat-transfer, heat-exchange or heat-storage materials C09K 5/00; arrangement or mounting of heat-exchangers in air-conditioning, air-humidification or ventilation F24F 13/30)
F 41 - WEAPONS
F 42 - AMMUNITION; BLASTING
SECTION G - PHYSICS
(1) - In this section, the following term is used with the meaning indicated:
"variable" (as a noun) means a feature or property (e.g., a dimension, a physical condition such as temperature, a quality such as density or colour) which, in respect of a particular entity (e.g., an object, a quantity of a substance, a beam of light) and at a particular instant, is capable of being measured; the variable may change, so that its numerical expression may assume different values at different times, in different conditions or in individual cases, but may be constant in respect of a particular entity in certain conditions or for practical purposes (e.g., the length of a bar may be regarded as constant for many purposes).
(2) - Attention is drawn to the definitions of terms or expressions used, appearing in the notes of several of the classes in this section, in particular those of "measuring" in class G01 and "control" and "regulation" in class G05.
(3) - Classification in this section may present more difficulty than in other sections, because the distinction between different fields of use rests to a considerable extent on differences in the intention of the user rather than on any constructional differences or differences in the manner of use, and because the subjects dealt with are often in effect systems or combinations, which have features or parts in common, rather than "things", which are readily distinguishable as a whole. For example, information (e.g., a set of figures) may be displayed for the purpose of education or advertising (G 09), for enabling the result of a measurement to be known (G 01), for signalling the information to a distant point or for giving information which has been signalled from a distant point (G 08). The words used to describe the purpose depend on features that may be irrelevant to the form of the apparatus concerned, for example, such features as the desired effect on the person who sees the display, or whether the display is controlled from a remote point. Again, a device which responds to some change in a condition, e.g., in the pressure of a fluid, may be used, without modification of the device itself, to give information about the pressure (G01L) or about some other condition linked to the pressure (another subclass of class G 01, e.g., G01K for temperature), to make a record of the pressure or of its occurrence (G07C), to give an alarm (G08B), or to control another apparatus (G 05).
The classification scheme is intended to enable things of a similar nature (as indicated above) to be classified together. It is therefore particularly necessary for the real nature of any technical subject to be decided before it can be properly classified.
G 01 - MEASURING (counting G06M); TESTING
G 02 - OPTICS (making optical elements or apparatus B24B, B29D 11/00, C03, or other appropriate subclasses or classes; materials per se, see the relevant places, e.g. C03B, C03C)
G 03 - PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY (reproduction of pictures or patterns by scanning and converting into electrical signals H04N) 
G 04 - HOROLOGY
G 05 - CONTROLLING; REGULATING
G 06 - COMPUTING; CALCULATING; COUNTING (score computers for games A63B 71/06, A63D 15/20, A63F 1/18; combinations of writing implements with computing devices B43K 29/08)
G 07 - CHECKING-DEVICES
G 08 - SIGNALLING (indicating or display devices per se G09F; transmission of pictures H04N)
G 09 - EDUCATING; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
G 10 - MUSICAL INSTRUMENTS; ACOUSTICS
G 11 - INFORMATION STORAGE
G 12 - INSTRUMENT DETAILS
G 21 - NUCLEAR PHYSICS; NUCLEAR ENGINEERING
SECTION H - ELECTRICITY
Note : These Notes cover the basic principles and general instructions for use of section H.
I. Section H covers:
(a) basic electric elements, which cover all electric units and the general mechanical structure of apparatus and circuits, including the assembly of various basic elements into what are called printed circuits and also cover to a certain extent the manufacture of these elements (when not covered elsewhere);
(b) generation of electricity, which covers the generation, conversion and distribution of electricity together with the controlling of the corresponding gear;
(c) applied electricity, which covers:
(i) general utilisation techniques, viz. those of electric heating and electric lighting circuits;
(ii) some special utilisation techniques, either electric or electronic in the strict sense, which are not covered by other sections of the Classification, including:
(1) electric light sources, including lasers;
(2) electric X-ray technique;
(3) electric plasma technique and the generation and acceleration of electrically charged particles or neutrons;
(d) basic electronic circuits and their control;
(e) radio or electric communication technique;
(f) the use of a specified material for the manufacture of the article or element described. In this connection, paragraphs 57 to 59 of the Guide should be referred to.
II. In this section, the following general rules apply:
(a) Subject to the exceptions stated in I(c), above, any electric aspect or part peculiar to a particular operation, process, apparatus, object or article, classified in one of the sections of the Classification other than section H, is always classified in the subclass for that operation, process, apparatus, object or article. Where common characteristics concerning technical subjects of similar nature have been brought out at class level, the electric aspect or part is classified, in conjunction with the operation, process, apparatus, object or article, in a subclass which covers entirely the general electrical applications for the technical subject in question;
(b) The electrical applications referred to under (a), above, either general or particular, include:
(i) the therapeutic processes and apparatus, in class A 61;
(ii) the electric processes and apparatus used in various laboratory or industrial operations, in classes B 01 and B 03 and in subclass B23K;
(iii) the electricity supply, electric propulsion and electric lighting of vehicles in general and of particular vehicles, in the subsection "Transporting" of section B;
(iv) the electric ignition systems of internal-combustion engines, in subclass F02P, and of combustion apparatus in general, in subclass F23Q;
(vvi) the whole electrical part of section G, i.e. measuring devices including apparatus for measuring electric variables, checking, signalling and calculating. Electricity in that section is generally dealt with as a means and not as an end in itself;
(c) All electrical applications, both general and particular, presuppose that the "basic electricity" aspect appears in section H (see I(a) above) as regards the electric "basic elements" which they comprise. This rule is also valid for applied electricity, referred to in I(c), above, which appears in section H itself.
III. In this section, the following special cases occur:
(a) Among the general applications covered by sections other than section H, it is worth noting that electric heating in general is covered by subclasses F24D or F24H or class F27, and that electric lighting in general is partly covered by class F 21, since in section H (see I(c), above) there are places in H05B which cover the same technical subjects;
(b) In the two cases referred to under (a), above, the subclasses of section F, which deal with the respective subjects, essentially cover in the first place the whole mechanical aspect of the apparatus or devices, whereas the electrical aspect, as such, is covered by subclass H05B;
(c) In the case of lighting, this mechanical aspect should be taken to cover the material arrangement of the various electric elements, i.e., their geometrical or physical position in relation to one another; this aspect is covered by subclass F21V, the elements themselves and the primary circuits remaining in section H. The same applies to electric light sources, when combined with light sources of a different kind. These are covered by subclass H05B, whereas the physical arrangement which their combination constitutes is covered by the various subclasses of class F 21;
(d) As regards heating, not only the electric elements and circuitry designs, as such, are covered by subclass H05B, but also the electric aspects of their arrangement, where these concern cases of general application; electric furnaces being considered as such. The physical disposition of the electric elements in furnaces is covered by section F. If a comparison is made with electric welding circuits, which are covered by subclass B23K in connection with welding, it can be seen that electric heating is not covered by the general rule stated in II, above.
H 01 - BASIC ELECTRIC ELEMENTS
H 02 - GENERATION, CONVERSION, OR DISTRIBUTION OF ELECTRIC POWER
H 03 - BASIC ELECTRONIC CIRCUITRY
H 04 - ELECTRIC COMMUNICATION TECHNIQUE
H 05 - ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
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