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POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
Definition statement
This subclass/group covers:

Pumps or compressors which cause a fluid to move by trapping a fixed amount of said fluid, and then forcing or displacing the trapped fluid into discharge means.

Reciprocating pumps or compressors causing the fluid to move using one or more oscillating pistons, plungers or flexible working members, i.e. membranes, diaphragms or tubes.

Relationship between large subject matter areas

Related subclasses F02M, F02B and F03C partly cover the same type of structural apparatus using reciprocating or oscillating pistons or flexible working members for positive displacement.

The characteristic used for distinguishing the types of machines is the working fluid used, i.e. a liquid for a pump and an elastic fluid for a compressor.

If the machine may be operated with a liquid as a working fluid both as a hydraulic engine and/or as a pump, then the document is classified in F03C and in F04B. However, if the machine may be operated only as a hydraulic motor, then the document is classified in F03C, and if the machine may be operated only as a pump, then the document is classified in F04B.

Hydraulic motors with reciprocating or rotary pistons for liquid working fluids are classified in F03C. Machines with reciprocating or rotary pistons for working fluids containing elastic fluids, e.g. a combination of liquids and elastic fluids are classified in F01C. Internal combustion piston engines or combustion engines in general, where the driving forces are generated by expansion of gases due to combustion are classified in F02B.

Subject matter like cyclically operating valves, lubricating or cooling are classified in subclasses F01L, F01M, F01P irrespective of their stated application, unless their novel and non-obvious features are peculiar to their application, in which case they are classified only in the relevant subclass of F04. The subclasses F01L, F01M, F01P do not cover pump or machine features per se.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Rotary-piston or oscillating piston machines for elastic fluids
Positive-displacement engines driven by liquids
Internal combustion piston engines or combustion engines in general
Rotary-piston or oscillating piston machines
Non-positive displacement pumps
Cyclically operating valves for machines or engines
Lubrication of machines or engines in general
Fuel injection apparatus
Cooling of machines or engines in general
Crankshafts, crossheads, connecting-rods
Flywheels
Rotary fluid gearing using pumps and motors of the volumetric type for conveying rotary motion
Sealing in general
Means for thermal insulation in general
Refrigeration machines, plants or systems
Dynamo electric machines
Special rules of classification within this subclass/group

Reciprocating piston type:

Documents indicating that the machine may be operated both as a hydraulic engine and/or as a pump are classified in F03C and in F04B.

In cases were pump/compressor control or control parameters thereof are of special interest, the document should be classified by using the corresponding Indexing Code of F04B.

In cases were a specific liquid handled by the pump is of special interest, the document should be classified by using the corresponding Indexing Code of F04B 15/00.

In cases were a material or material properties are of special interest, the document should be classified by using the corresponding Indexing Code of F05C.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Pump
Device for continuously raising, forcing, compressing, or exhausting fluid by mechanical means
Machine
Device that could equally be both 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 pumps
Pumps using pistons or other mechanical members to displace a working fluid in a working chamber, the dynamic effect on the fluid being of minor importance
Positive displacement engines
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 movement of mechanical members, e.g. pistons transmitting the energy, the dynamic effect of the fluid being of minor importance
Oscillating piston machine
Positive-displacement machine in which a fluid-engaging, work-transmitting member oscillates, e.g. a vane piston swinging back and forth about a fixed axis
Reciprocating piston
A fluid-engaging, work-transmitting member of an reciprocating-piston type machine or pump that slides alternately back and forth usually along a straight line or path
Rotary piston
A fluid engaging, work-transmitting member of a rotary-piston machine or pump that can completely rotate about a fixed axis or about an axis moving along a circular or similar orbit when operating, e.g. rotor having vanes or teeth
Free-piston machine
A linear , "crankless" reciprocating piston machine in which the piston motion is not controlled by a crankshaft but determined by the interaction forces from the fluid pressure in the working chamber, a rebound device (e.g. a piston in a closed cylinder) and a load device (e.g. a gas compressor or a linear alternator)
Rotary piston machine
Positive-displacement machine in which a liquid-engaging, work-transmitting member rotates about a fixed axis or about an axis moving along a circular or similar orbit, e.g. machine with a rotor having vanes or teeth
Cooperating members
The "oscillating piston" or "rotary piston" and another member, e.g., the working-chamber wall, which assists in the pumping action or machine's action
Movement of the cooperating members
To be interpreted as relative, so that one of the "cooperating members" may be stationary, even though reference may be made to its rotational axis, or both may move
Teeth or tooth equivalents
Includes lobes, projections or abutments
Internal axis type
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
Working fluid
Driven fluid in a pump or driving or driven liquid in a machine. The working fluid can be in a compressible, gaseous state, e.g. steam, called elastic fluid, a liquid state, or a state where there is coexistence of elastic fluid and liquid state
Synonyms and Keywords

In patent documents the following terms are often used as synonyms:

"piston" and "plunger";

"membrane" and "diaphragm".

Multi-cylinder machines or pumps characterized by number or arrangements of cylinders
Definition statement
This subclass/group covers:

Pumps for liquids defined by the number of cylinders (e.g. having two or more cylinders) or by the arrangement of the cylinders (e.g. radial piston pumps with cylinders in star or fan arrangement, or axial piston pumps with cylinders parallel or inclined with respect to a main shaft).

References relevant to classification in this group
This subclass/group does not cover:
Compressors, i.e. pumps for elastic fluids

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

For raising fluid from great depths
Informative references
Attention is drawn to the following places, which may be of interest for search:
Reciprocating-piston engines
Special rules of classification within this group

If a document concerns embodiments which are covered by several subgroups dependent on a higher hierarchy head group, e.g. valve types F04B 1/0452, the following classification rules apply:- the specific technical information relevant for some of the subgroups is classified in all of said subgroups;- if generic technical information common to all of the subgroups is disclosed and only schematic embodiments are represented, then the document is classified in the higher hierarchy head group.

Machines or pumps with pistons coacting within one cylinder e.g. multi-stage
Definition statement
This subclass/group covers:

Pumps for liquids, wherein two or more pistons reciprocate within one cylinder, or wherein one piston forms the cylinder of a further piston.

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

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

For raising fluid from great depths
Machines or pumps with differential surface pistons
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for liquids, with stepped pistons or with double-acting pistons.

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

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

For raising fluid from great depths
Piston machines or pumps characterized by having positively-driven valving
Definition statement
This subclass/group covers:

This subclass/group covers:

Valves and distribution members being mounted in or adapted for pumps, wherein the valves are mechanically driven, actuated by electro-magnetic means, fluid actuated, or by reciprocating pistons.

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

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

For raising fluid from great depths
Piston machines or pumps characterized by the driving or driven means to or from their working members
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for liquids driven by mechanical means, e.g. cams, eccentrics or other means or by fluid means, e.g. hydraulically driven or pneumatically driven. In this group are also classified pumps being manually driven by a user.

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

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

For raising fluid from great depths
Special rules of classification within this group

If a document concerns embodiments which are covered by several subgroups dependent on a higher hierarchy head group, e.g. mechanical means F04B 9/02, the following classification rules apply:- the specific technical information relevant for some of the subgroups is classified in all of said subgroups;- if generic technical information common to all of the subgroups is disclosed and only schematic embodiments are represented, then the document is classified in the higher hierarchy head group.

Equalization of pulses, e.g. by use of air vessels; Counteracting cavitation
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for liquids comprising means for preventing problems occurring with pulsation, vibration and/or cavitation.

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

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

For raising fluid from great depths
Pumps specially modified to deliver fixed or variable measured quantities
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for liquids specially adapted for dosing purposes or for mixing two or more fluids.

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

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

For raising fluid from great depths
Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps specially adapted for pumping e.g. viscous fluids, fluids at high temperatures, corrosive fluids or cryogenic fluids.

Various types of pumps for liquids and for elastic fluids not provided for in other groups, e.g. pumps for corrosive fluids or for cryogenic fluids.

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

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

For raising fluid from great depths
Pumps characterized by combination with, or adaptation to, specific driving engines or motors
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for liquids driven by specific engines or other driving means, such as e.g. electric motors, piezo-electric means, solar means, wind energy, or combustion engines. In this group are also classified mobile pumping systems, e.g. pumps on vehicles.

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

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

For raising fluid from great depths
Machines or pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B 1/00-F04B 17/00
Definition statement
This subclass/group covers:

This subclass/group covers:

In this group are classified various types of pumps not provided for in other groups, such as e.g. free-piston pumps, micro-pumps, pumps with movable cylinders, pumps for storage containers, scoop devices adhesion type pumps, or pumps using the effect of heat expansion.

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

This subclass/group does not cover:

Micro-pumps having plate-like flexible members.

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

For raising fluid from great depths
Pumping installations or systems
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for liquids combined with reservoirs or with other fluid pumps.

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

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

For raising fluid from great depths
Multi-stage pumps
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for elastic fluids, e.g. gas or steam, having more than one pumping stage, e.g. with two or more cylinders or with stepped pistons.

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

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

For raising fluid from great depths
Multi-cylinder pumps characterised by number or arrangement of cylinders
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for elastic fluids, e.g. gas or steam, defined by the number of cylinders, e.g. having two or more cylinders, or by the arrangement of the cylinders, e.g. radial piston pumps with cylinders in star or fan arrangement, or axial piston pumps with cylinders parallel or inclined with respect to a main shaft.

Details relating to control systems and methods for pumps for elastic fluids , e.g. gas or steam, defined by having cylinders coaxial with, or parallel or inclined to, main shaft axis.

References relevant to classification in this group
This subclass/group does not cover:
Pumps for liquids

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

For raising fluid from great depths
Special rules of classification within this group

If a document concerns embodiments which are covered by several subgroups dependent on a higher hierarchy head group, e.g. valve types classified in F04B 27/0451; crankcase pressure control classified in F04B 27/1804, the following classification rules apply:- the specific technical information relevant for some of the subgroups is classified in all of said subgroups;- if generic technical information common to all of the subgroups is disclosed and only schematic embodiments are represented, then the document is classified in the higher hierarchy head group.

Other pumps with movable, e.g. rotatable cylinders
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for elastic fluids, e.g. gas or steam, being characterised by rotatable cylinders.

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

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

For raising fluid from great depths
Free-piston pumps; Systems incorporating such pumps
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for elastic fluids, e.g. gas or steam, being of free-piston type.

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

This subclass/group does not cover:

Free-piston engines.
Free-piston pumps for liquids

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

For raising fluid from great depths
Pumps actuated by muscle power, e.g. for inflating
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for elastic fluids specially adapted for manual operation and for inflating tyres.

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

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

For raising fluid from great depths
Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements of tyre-inflating valves to tyres or rims
Piston pumps characterized by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for elastic fluids, e.g. gas or steam, driven by specific engines or other driving means, such as e.g. electric motors, floating elements, steam engines, or combustion engines; Mobile pumping systems, e.g. compressors on vehicles.

Pumps having pertinent characteristics not provided for in, or of interest apart from, groups
Definition statement
This subclass/group covers:

This subclass/group covers:

Various types of pumps for elastic fluids, e.g. gas or steam, not provided for in other groups, such as e.g. vacuum pumps evacuating by absorption means, vacuum pumps evacuating by thermal means, pumps for very high or very low pressure, or pumps for wet gases.

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

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

For raising fluid from great depths
Component parts, details, or accessories, of pumps or pumping systems, not otherwise provided for in, or of interest apart from, groups
Definition statement
This subclass/group covers:

This subclass/group covers:

Various components adapted for pumps for elastic fluids, e.g. gas or steam, such as e.g. piston means, pulsation damping means, lubrication means, cooling means, filtering means, compressor valves, compressor casings.

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

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:

For raising fluid from great depths
Lubrication
Definition statement
This subclass/group covers:

This subclass/group covers:

Lubrication of pumps for liquids and elastic fluids.

Pumping installations or systems
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for elastic fluids, e.g. gas or steam, combined with reservoirs or with other fluid pumps.

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

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

For raising fluid from great depths
Machines, pumps, or pumping installations having flexible working members
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps for liquids and for elastic fluids having flexible working members, such as diaphragms, tubular flexible members or pumps with peristaltic action; Micro-pumps having flexible working members.

Pumps or pumping installations having flexible working members and specially adapted for elastic fluids
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps having flexible working members and which are specifically adapted for elastic fluids. The flexible working members may be bellows, diaphragms or tubular flexible members.

Pumps or pumping installation specially adapted for raising fluids from great depths, e.g. well pumps
Definition statement
This subclass/group covers:

This subclass/group covers:

Pumps specifically adapted for raising fluids from great depths, such as wellbore pumps.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
Control of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, group
Definition statement
This subclass/group covers:

This subclass/group covers:

Control systems and methods for pumps for liquids and for elastic fluids.

Special rules of classification within this group

If a document concerns embodiments which are covered by several subgroups dependent on a higher hierarchy head group, e.g. variable length of piston stroke classified in F04B 49/12, the following classification rules apply:- the specific technical information relevant for some of the subgroups is classified in all of said subgroups;- if generic technical information common to all of the subgroups is disclosed and only schematic embodiments are represented, then the document is classified in the higher hierarchy head group.

Testing machines, pumps, or pumping installations
Definition statement
This subclass/group covers:

This subclass/group covers:

Systems and methods for testing pumps for liquids and for elastic fluids.

Component parts, details or accessories not provided for in, or of interest apart from, groups F04B 1/00 to F04B 23/00 or F04B 39/00 to F04B 47/00
Definition statement
This subclass/group covers:

This subclass/group covers:

In this group are classified various components adapted for pumps for liquids and for elastic fluids, e.g. piston means, pulsation and noise damping means, lubrication means, cooling means, filtering means, compressor valves, housings or casings.

Pump parameters
Definition statement
This subclass/group covers:

This subclass/group covers:

Pump control parameters for pumps for liquids and elastic fluids.

Motor parameters
Definition statement
This subclass/group covers:

This subclass/group covers:

Motor control parameters of pumps for liquids and elastic fluids.

Fluid parameters
Definition statement
This subclass/group covers:

This subclass/group covers:

Fluid parameters relating to pumps for liquids and elastic fluids.

External parameters
Definition statement
This subclass/group covers:

This subclass/group covers:

External parameters relating to pumps for liquids and elastic fluids.

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Last Modified: 10/11/2013