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NON-POSITIVE DISPLACEMENT PUMPS
Definition statement
This subclass/group covers:

Non positive displacement pumps for liquids, for elastic fluids, or for liquids and elastic fluids, whether rotary or not having pure rotation.

References relevant to classification in this subclass
This subclass/group does not cover:
Aeroplane propellers
Non positive displacement machines or engines
Machines or engines for liquids
Wind motors
Combinations of non-positive displacement pumps with other pumps; Positive displacement machines for fluids Pumps
Rotary-piston, or oscillating piston, positive displacement machines for fluids
Informative references
Attention is drawn to the following places, which may be of interest for search:
Blood pumps
Obtaining oil, gas, water from deep wells
Pumping cooling air or liquid coolants
Bearings
Sealings
Central heating systems
Air conditioning, Ventilation
Special rules of classification within this subclass

As a general rule a complete classification will contain at least one class out of the 2 first main parts which would specify the type of pump concerned, combined with at least one class out of the main group F04D 29/00.

In cases were a "Details, component, parts, or accessories" has to be classified which can be used in a number of different types of pumps which would be covered by different sub groups, only the relevant F04D 29/00 sub group class should be given.

Care should be taken when classifying compressors used in combination with gas turbines. Classification in F04D when compressor details are predominant. Classification in F01D when the integration or the fluid connection to the turbine or its combustion chamber are involved

This subclass is generally subdivided in 3 main parts:

In the part related to "Details, component, parts, or accessories" i.e. main group F04D 29/00 each sub group is subdivided in two further subgroups, one for elastic fluids and another on for non elastic fluids. By way of example: F04D 29/02 has a subgroup F04D 29/023 covering the elastic fluids, and another subgroup F04D 29/026 covering the non elastic fluids.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning 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
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
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
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
Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps ( adapted for pumping specific fluids F04D 7/00 ; priming or boosting F04D 9/00)
Definition statement
This subclass/group covers:

Radial and mixed flow type pumps for non elastic fluids

References relevant to classification in this group
This subclass/group does not cover:
Shear force pumps
Adaptation to specific liquids
Priming of pumps
Synonyms and Keywords

In patent documents the following expressions/words "helico centrifugal flow", "mixed flow" and "diagonal flow" are often used.

Axial-flow pumps ( priming or boosting F04D 9/00)
Definition statement
This subclass/group covers:

Axial flow type pumps for non elastic fluids.

References relevant to classification in this group
This subclass/group does not cover:
Adaptation to specific liquids
Priming of pumps
Informative references
Attention is drawn to the following places, which may be of interest for search:
Conveyers
Archimedes screw pumps
Pumps with circumferential or transverse flow { ( control thereof F04D 15/005) }
Definition statement
This subclass/group covers:

Shear force pumps and pumps with circumferential or transverse flow, also shear force pumps, although they are generally of radial type.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Shear force pump
a pump where the energy is transferred to the liquid by friction forces
Synonyms and Keywords

In patent documents the following expressions/words "circumferential flow pump", "side channel pump", "regenerative pump", "peripheral flow pump" and "vortex flow pump" are often used.

Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts (F04D 11/005 , F04D 29/22 take precedence )
Definition statement
This subclass/group covers:

Adaptations which make a pump suitable for a specific liquid.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Pumping specific fluids in general
Special rules of classification within this group

In general classification is combined with a sub group in the F04D 29/00 group

Priming; Preventing vapour lock
Definition statement
This subclass/group covers:

All adaptations of a pump in order to prime the pump, to avoid vapor lock or to avoid loss of prime

Other rotary non-positive-displacement pumps ( pumping installations or systems F04D 13/00)
Definition statement
This subclass/group covers:

Any rotary non-positive displacement which does not have radial, axial or helico centrifugal flow.

Pumping installations or systems ( controlling F04D 15/00)
Definition statement
This subclass/group covers:

The combination of a pump with its drive system or its integration into a system either comprising several pumps or comprising storage systems

References relevant to classification in this group
This subclass/group does not cover:
Control of pumps
Informative references
Attention is drawn to the following places, which may be of interest for search:
Electrical machines
Magnetic couplings
Control, e.g. regulation, of pumps, pumping installations or systems
Definition statement
This subclass/group covers:

Systems and schemes for controlling a pump, either matching the pump to the requirements of the system or avoiding harmful conditions for the pump

Informative references
Attention is drawn to the following places, which may be of interest for search:
Actuators for control action
Radial-flow pumps e.g. centrifugal pumps; Helico-centrifugal pumps (F04D 21/00 takes precedence )
Definition statement
This subclass/group covers:

Radial and mixed-flow type pumps for elastic fluids.

Special rules of classification within this group

The centrifugal pumps for elastic fluids are subdivided into 2 main parts; in the "compressing or evacuating" sub group F04D 17/10 the compression ratio should be significant, while in the "for displacing without appreciable compression" sub group F04D 17/16 the generation of flow is predominant

Synonyms and Keywords

In patent documents the following expressions/words "helico centrifugal flow", "mixed flow" and "diagonal flow" are often used.

Axial-flow pumps (F04D 21/00 takes precedence ) ; { pump comprising axial flow and radial flow stages F04D 17/025}
Definition statement
This subclass/group covers:

Axial flow type pumps for elastic fluids.

References relevant to classification in this group
This subclass/group does not cover:
Combined axial-flow and radial-flow stages
Pumps involving supersonic speeds in the pumped fluid
Special rules of classification within this group

The axial pumps for elastic fluids are subdivided into 2 main parts; in the "multistage pumps" sub group F04D 19/02 the compression ratio should be significant, while in the "fan" sub groups F04D 19/002 and F04D 19/007 the generation of flow is predominant

Pump involving supersonic speed of pumped fluids
Definition statement
This subclass/group covers:

All pump for elastic fluids involving supersonic speed of pumped fluids.

Other rotary non-positive-displacement pumps ( pumping installations or systems F04D 25/00)
Definition statement
This subclass/group covers:

Any rotary non positive displacement which does not have radial, axial or helico centrifugal flow, pumps adapted for conveying or for handling specific elastic fluid, and pumps with circumferential or transverse flow.

Pumping installations or systems ( controlling F04D 27/00)
Definition statement
This subclass/group covers:

The combination of a pump for elastic fluids with its drive system or its integration into a system either comprising several pumps or comprising storage systems.

References relevant to classification in this group
This subclass/group does not cover:
Pump installation control
Informative references
Attention is drawn to the following places, which may be of interest for search:
Hand held fans
Special rules of classification within this group

F04D 25/06 and F04D 25/08 are both used in parallel . F04D 25/06 focusses on the motor design, or the combination of motor and pump. F04D 25/08 focusses on specific design for special purposes. Both subgroups can be used in combination (e.g. a computer fan with an inside out motor and details on how the motor is cooled will get both F04D 25/0613 and F04D 25/082 classification

Control, e.g. regulation, of pumps, pumping installations or systems
Definition statement
This subclass/group covers:

Systems and schemes for controlling a pump for elastic fluids, either matching the pump to the requirements of the system or avoiding harmful conditions for the pump, e.g. surge or stall conditions.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Control of flow
Control of pressure
Special rules of classification within this group

F04D 27/02 subgroup is used for ANY type of control and is thus not limited to surge or stall control

F04D 27/001 is used when the detection of pump condition is predominant (e.g. determining of surge margin, without immediate control action; mapping of pump characteristics for later use)

Details, component parts, or accessories ( machine elements in general F16)
Definition statement
This subclass/group covers:

Details, component parts, or accessories of any type of pump for elastic or non elastic fluids.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Making blades for propellers or turbines
Making specific metal objects
Machine elements in general
Special rules of classification within this group

In main group F04D 29/00 each sub group is subdivided in two further subgroups, one for elastic fluids and another on for non elastic fluids. By way of example: F04D 29/02 has a subgroup F04D 29/023 covering the elastic fluids, and another subgroup F04D 29/026 covering the non elastic fluids.

However for the subgroups relating to bearing and shafts (F04D 29/04 and F04D 29/05) and rotors (F04D 29/18 and F04D 29/26) specific subgroups are provided for elastic fluids and non-elastic fluids.

Pumping liquids and elastic fluids at the same time
Definition statement
This subclass/group covers:

Pumping liquids and elastic fluids at the same time, i.e. one pump handles both elastic and non elastic fluids together.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Obtaining oil, gas, water from deep wells
Non-positive-displacement pumps with other than pure rotation, e.g. of oscillating type (F04D 35/00 takes precedence; hand-held fans A45B)
Definition statement
This subclass/group covers:

Non-positive-displacement pumps with other than pure rotation. Some examples are mechanisms imitating the movement of a bird wing or a fish tale, or the movement produced by humans when using a hand fan.

References relevant to classification in this group
This subclass/group does not cover:
Wave generators
Pumps producing waves in liquids, i.e. wave.producers ( for bath tubs A47K 3/10)
Definition statement
This subclass/group covers:

Non-positive-displacement pumps for the generation of waves.

References relevant to classification in this group
This subclass/group does not cover:
Wave generators for baths and tubs
Informative references
Attention is drawn to the following places, which may be of interest for search:
Swimming pools
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Last Modified: 10/11/2013