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Publication numberUS3420180 A
Publication typeGrant
Publication dateJan 7, 1969
Filing dateJul 21, 1967
Priority dateJul 21, 1967
Publication numberUS 3420180 A, US 3420180A, US-A-3420180, US3420180 A, US3420180A
InventorsBehrends Bertwin E, Schmitt James L
Original AssigneeCaterpillar Tractor Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Gear pump
US 3420180 A
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Description  (OCR text may contain errors)

United States Patent O 2 Claims ABSTRACT F THE DISCLOSURE A gear pump having a pair of interengaging gears rotatable in a chamber, two inlet ports for admitting uid from two separate sources and in a set ratio into the chamber, each of the gear wheels serving to impel uid from one of the sources toward an outlet port, the uid from the two inlet ports being combined at the outlet port.

Gear pumps usually include two inter-engageable gear wheels which rotate in a pump chamber. The two wheels serve to draw fluid from a single chamber inlet port and to expel it through a chamber outlet port. Gear pumps have often been employed for purposes in which it is desirable to pump fluids from two separate sources. Where gear pumps have been so used, it has usually `been necessary to employ two pumps, each connected to one of the separate sources. Such use of two pumps has presented disadvantages, both with respect to increased costs and increased space requirements.

Attempts have been made to direct the fluid from the two separate sources into the inlet port of a single pump. This fails to provide an adequate degree of control over the pumping operation. In particular, it has not been possible to pump the uids from the separate sources in a fixed ratio. Since the uids pumped may differ in resistance to the pump suction, an undesirably large proportion of one fluid may be pumped as compared to the amount of the other fluid being pumped.

Gear pumps have been employed for pumping cooling oil to the brakes of an automotive vehicle such as a tractor. The oil employed has often been drawn from the torque converter scavenge sump of the vehicle. Such oil has not always provided adequate cooling of the 'brakes when overheated. It has, therefore, been considered desirable to provide cooling oil in a xed ratio `from two separate sources. The cost of providing additional cooling oil has been prohibitive because of the need for a second pump and the provision of space for two pumps.

The present invention is designed to overcome the above discussed problems of the prior art. The advantages of the invention will become apparent to one skilled in the art trom the following description when read in conjunction with the accompanying drawing which is a medial cross sectional fview of a pump constructed in accordance with the invention.

In the drawing, there is shown a gear pump which embodies the present invention. The pump 10 provides a housing 12 which denes a chamber 14. The chamber 14 has an outlet port 16.

Mounted within the chamber 14 are a pair of gears 20 and 22. Each of the gears 20 and 22 has teeth 24 which define cavities 25 therebetween. The gear 20 is rotatable in a clockwise direction while the gear 22 is rotatable in a counterclockwise direction. The gears are positioned for inter-engagement of their teeth approximately at the center of the chamber 14. The teeth 24, when disengaged, pass in close proximity to the wall surface 26 of the chamber 14.

Two inlet ports 32 and 34 are disposed at opposite sides of the chamber 14.

In order that more lluid will be drawn by the pump through one inlet than through the other, an inlet ratio bypass passageway is provided at 36. It extends between inlet passage 32, as at 38, to a point 40 in the gear chamber upstream of the point where inlet 34 enters.

In the operation of the pump 10, fluid from a first source enters the chamber 14 through the passageway 32. Such fluid is impelled by the rotating gear 20 through the chamber 14 and through the outlet port 16.

Fluid from a second source similarly enters the chamber 14 through the inlet passageway 34. This uid is impelled by the gear 22 toward and through the outlet port 16. Because of the bypass 36, some uid from inlet 32 ows to gear 22 and is propelled by it toward the outlet. This reduces the capacity of gear 22 to receive and transfer uid from inlet 34.

The bypass or ratio-change passageway 36 provides a means for increasing the amount of fluid admitted from the passageway 32 as compared to the amount of fluid admitted from the passageway 34. The size of the passageway is designed to provide the desired ratio of ow from two sources and the ratio will remain substantially constant at different pump speeds since the pump is of bsometric design between each inlet and the outlet.

The pump may be employed yfor such purposes as the provision of cooling oil to the brakes of a tractor. It might thus be -used to scavenge the torque converter by sucking oil and air from the latter through the inlet passageway 34. At the same time, oil from a separate reservoir might be drawn through the inlet passageway 32. Such separate reservoir might, for example, be the bevel gear case sump. The oil from the two sources would then be combined at the outlet 16 in a set ratio for use for brake cooling purposes.

The use of the pump provides savings in both cost and space requirements as compared to the use of two separate pumps for pumping the uids from the two separate sources.

We claim:

1. A gear pump comprising:

(a) a housing defining a chamber having a iluid outlet port;

(b) a pair of inter-meshing -gears rotatable in said chamber and each adapted to impel uid toward said outlet port;

(c) means defining a rst fluid inlet port for said chamber and being adapted to introduce fluid between the teeth of one of said gears; and

(d) means defining a second iiud inlet port for said chamber and being adapted to introduce iiuid between the teeth of the other of said gears, said inlet ports being located at opposite sides respectively of said chamber, means to increase the rate 0f flow of uid introduced Ibetween the teeth of one of said gears as compared to the rate of flow of fluid introduced between the teeth of the other of said gears, said means comprising a ratio-change passageway arranged to receive tluid from one inlet passageway and to direct it to the gear adjacent the other inlet passageway.

3 4 2. A pump in accordance with claim 1 in which the 2,944,487 7/ 1960 Walsh 103-7 passageway directs uid to the gear prior to the direc- 3,018,641 1/ 1962 Carpigiani. tion of uid thereto by said other passageway. 3,080,819 3/ 1963 Mayes.

3,137,137 6/1964 Klle ..-103-7 X References Cited 5 3,242,867 3/1966 Mosbacher 103--126 X 1 631 591 FTES PATENTS 103 7 DONLEY J. STOCKING, Primary Examiner.

1 1,687,523 10/1928 Stande. WARREN J. KRAUSS, ASSSaZ Examiner. 1,902,346 3/1933 Vogt. 2,301,496 11/1942 Aldrich 10s-2X 10 103 126 7 U-S- Cl- X-R- 2,820,416 1/ 1958 Compton.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1631591 *Jun 7, 1926Jun 7, 1927Hill Compressor & Pump CompanyCombined liquid and air pump
US1687523 *Feb 15, 1926Oct 16, 1928Staude Edwin GFluid-pressure pump for power-propelled vehicle-controlling means
US1902346 *Aug 23, 1930Mar 21, 1933Vogt Instant Freezers IncRotary pump
US2301496 *Mar 24, 1941Nov 10, 1942Aldrich Loyd IFuel pumping system
US2820416 *Dec 24, 1952Jan 21, 1958Borg WarnerPressure loaded pump
US2944487 *Aug 3, 1956Jul 12, 1960Cherry Burrell CorpGear pump
US3018641 *Mar 31, 1959Jan 30, 1962Poerio CarpigianiContinuous ice cream freezer and dispenser
US3080819 *Mar 15, 1957Mar 12, 1963Mayes Ronald WayneFuel feeding system
US3137137 *Sep 28, 1962Jun 16, 1964Kalle Karl TorstenRegulator
US3242867 *Mar 11, 1964Mar 29, 1966Roper Ind IncFluid pumping and separating apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3479957 *May 2, 1968Nov 25, 1969Phelan Louis A MPositive displacement gear type pump
US4093407 *Dec 10, 1976Jun 6, 1978Imperial Chemical Industries Inc.Injection of additives into liquid streams
US4338274 *Oct 10, 1980Jul 6, 1982General Engineering Radcliffe 1979 LimitedMethod and apparatus for the incorporation of additives into plastics materials
US4790454 *Jul 17, 1987Dec 13, 1988S. C. Johnson & Son, Inc.Self-contained apparatus for admixing a plurality of liquids
US5505591 *Sep 28, 1994Apr 9, 1996Tynan; Daniel G.Apparatus for processing materials
US7094042Apr 1, 2004Aug 22, 2006Hamilton Sundstrand CorporationDual-inlet gear pump with unequal flow capability
US7395948Sep 13, 2004Jul 8, 2008Rafael Advanced Defense Systems Ltd.Multiple tank fluid pumping system using a single pump
US7597145Jun 27, 2005Oct 6, 2009Blue Marble Engineering, L.L.C.Fluid-flow system, device and method
US8075288 *Jan 14, 2005Dec 13, 2011Edwards LimitedScrew pump and pumping arrangement
US8469231 *Oct 5, 2005Jun 25, 2013Hewlett-Packard Development Company, L.P.Mixing rotary positive displacement pump for micro dispensing
US20130175290 *Aug 10, 2011Jul 11, 2013Heraeus Medical GmbhSynchronised dispensing device, method for synchronising flows, and method for mixing a mixable material
EP0812988A1 *Jun 9, 1997Dec 17, 1997Paul Troester MaschinenfabrikProcess and apparatus for the extrusion of caoutchouc mixtures by means of a gear pump
EP1517040A2 *Sep 16, 2004Mar 23, 2005Rafael - Armament Development Authority Ltd.Multiple tank fluid pumping system using a single pump
U.S. Classification418/15, 418/206.4
International ClassificationF04C13/00
Cooperative ClassificationF04C13/00
European ClassificationF04C13/00