IPC Definitions - January 01, 2012
F04C - Definition
This subclass covers:
Pumps with rotary or oscillating pistons for liquids, for elastic fluids, or for combination of liquid and elastic fluid.
Positive displacement machines, i.e. devices which could be equally an engine or pump, with rotary or oscillating pistons for liquids only.
Relationship between large subject matter areas
Related subclasses F01C and F04C cover the same type of apparatus using rotary or oscillating pistons for positive displacement. The distinguishing characteristic used for classifying the machines, i.e. devices which could be equally be an engine or pump, is the working fluid used. Machines with rotary or oscillating pistons for working fluids containing elastic fluids, e.g. a combination of liquids and elastic fluids are classified in F01C. If only liquid is used as working fluid for these machines with rotary or oscillating pistons they are classified in F04C. However, devices with rotary or oscillating pistons that are only pumps, i.e. cannot be used as engines, are classified in F04C, irrespective of the working fluid.
F04B covers machines or pumps with reciprocating pistons, or other kinds of positive displacement mechanisms with the exception of rotary or oscillating piston type machines or pumps.
Subject matter like cyclically operating valves, lubricating or cooling are classified in subclasses F01LF01M, 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 F01LF01M, F01P do not cover pump or machine features per se.
References relevant to classification in this subclass
This subclass does not cover:
Positive displacement machines for liquids, or pumps in which the working-fluid is displaced by one or more reciprocating pistons or by flexible working members | F04B |
Attention is drawn to the following places, which may be of interest for search:
Rotary-piston or oscillating piston machines for elastic fluids | F01C |
Rotary-piston or oscillating piston machines for liquids and elastic fluids | F01C |
Cyclically operating valves for machines or engines | F01L |
Lubrication of machines or engines in general | F01M |
Gas-flow silencer or exhaust apparatus for machines or engines in general | F01N |
Cooling of machines or engines in general | F01P |
F02B 33/34, F02B 53/08 | |
Fluid pressure actuators | F15B |
Rotary fluid gearing using pumps and motors of the volumetric type for conveying rotary motion | F16H |
Sealing in general | F16J |
Means for thermal insulation in general | F16L |
Refrigeration machines, plants or systems | F25B |
In this subclass, the following terms or expressions are used with the meaning indicated:
Pump | means a device for continuously raising, forcing, compressing, or exhausting fluid by mechanical means |
Machine | means a 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 | means a 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 | means 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 | means 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 |
Rotary piston machine | means a 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 | means 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 | is 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 | 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 |
Working fluid | means the 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 |