US2649740A

US2649740A - High-pressure pump

Info

Publication number: US2649740A
Application number: US166376A
Authority: US
Inventors: John F Murray; James C Osborne
Original assignee: Thompson Products Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1950-06-06
Filing date: 1950-06-06
Publication date: 1953-08-25
Anticipated expiration: 1970-08-25

Description

Aug. 25, 1953 J. F. MURRAY ET AL 2,649,740

HIGH-PRESSURE PUMP Filed June 6, 1950 3 Sheets-Sheet 1 H [DJ EUZURE L/OHN MURRAY JAMES OSBORNE Aug. 25, 1953 J. F. MURRAY ET AL 2,649,740

HIGH-PRESSURE! PUMP Filed June 6, 1950 s Sheets-Sheet 2 JOHN F MURRAY JAMES OS BOPNE JOHN JAMES C OSBORNE Patented Aug. 25, 1953 HIGH-PRESSURE PUMP John F. Murray, Macedonia, and James C. 0s-

borne, Cleveland Heights, Ohio, assignors to Thompson Products, Inc., Cleveland, Ohio, a

corporation of Ohio Application June 6, 1950, Serial No. 166,376

12 Claims. 1

r This invention relates generally to ressure loaded gear pumps and more particularly to pressure loaded gear pumps of the type having movable bushings therein which serve the dual purpose of, journalling the shaft portions of gear type fluid displacement means and forming together with the body of the gear pump a control pressure chamber whereby the bushings may be moved axially into pressure sealing relationship with the sides of the gear type fluid displacement means, the particular features of the present invention involving the utilization of movable bushings having a recess formed at the respective engaging abutment portions thereof adapted to receive 'an axially extending sealing member integrally formed as a part of an O-ring gasket to more efliciently and more efiectively seal the path of leakage between the low-pressure inlet and high-pressure outlet portions of the pump structure.

In our copending application; U..S. Serial No. 102,404, filed June 30, 1949, a high-pressure gear pump is disclosed having movable bushings therein defining an eccentrically disposed end plate portion defining together with the body of the pump acontrol pressure chamber by means of which the movable bushings could be urged into pressure sealing relationship with the sides of the'gear type fluid displacement means with the actual pressure thrusts varying progressively with respect to the relative disposition of the pump' inlet and the pump outlet. 7

According to the general features of the present invention, an improved sealing arrangement is provided for the pump structure.

The movable bushings of the pressure loaded gear pump according to the present invention are provided with radially extending end plate portions which are relatively eccentrically disposed with respect to the bearing portions formed integrally therewith andadapted to journal the shaft of the gear type rotary fluid displacement means. When viewed endwise, the general configuration of the end plate portions is substantially circular, however, since the bores of the pump body which define the pumping chamber comprise generally intersecting cylindrical portions essentially figure eight-shaped'in crosssection, each of the end plate portions of the movable bushings are provided with a flattened abutment surface so that the pair of movable bushings provided for a pump unit may be assembled in engaging relationship within the pumping chamber of thepump. v r 7 :As shown in the disclosure of the acknowled ed copending application, a figure eight-shaped O-ring gasket may be provided to peripherally surround the end plate portions of the movable bushings to provide an axial seal between the movable bushings and the body of the pump, however, we have found that special provision must be made to preclude leakage across the path existing between the end plate portions of the movable bushings from the high pressure outlet side of the pump toward the comparatively low pressure inlet side of the pump.

To that end we have provided a complexly shaped recess partially defined by each of the end plate portions of the movable bushings.

A nubbin extending axially of and formed integrally with the figure eight-shaped O-ring gasket is provided, the nubbin when taken in cross-section defining a shape complementary to that of the recess defined by the movable bushings. The nubbin is received by the recess and effectively blocks the leakage path between the end plate portions and precludes leakage from the high pressure side of the pump to the low pressure side.

It is an object, therefore, of the present invention to provide a pressure loaded gear pump having an improved sealing arrangement to preclude the leakage of fluid from the high pressure side of the pump to the low pressure side of the pump along a leakage path between the end plate portions of the movable bushings contained therein.

Another object of the present invention is to provide a novel sealing element which performs the dual function of sealing movable pressure loading bushings in a gear pump radially as well as axially. V 7

An additional object of the present invention is to provide a pressure loaded gear pump structure which not only contemplates the uniform pressure loading of movable bushings therein but, in addition, is provided with structural elements of such a nature as to permit ready reversibility thereof for reverse operation of the pump.

Many other features, advantages, and additional objects of the present invention will become manifest to those versed in the art upon making reference to the following detaileddescription and the annexed sheets of drawings in which a preferred embodiment of a pressure ,loaded gear pump according to the present in- ,vention is shown.

On the drawings: Figure 1 is an elevational plan view of a pres- U sure loaded gear pump according to the present invention;

Figure 2 is an end elevational view of the pump shown in Figure 1;

Figure 3 is an enlarged cross-sectional view taken on line III-III of Figure 1;

Figure 4 is a cross-sectional View taken on line IVIV of Figure 3;

Figure 5 is a cross-sectional view similar to Figure 4 but with parts of the pump reversed through 180 for reverse operation of the pump;

Figure 6 is an enlarged fragmentary perspective view with parts broken and with parts shown in cross-section of the sealing element employed in the pump of the present invention; and

Figure 2 is an enlarged fragmentary crosssectional view showing a modified liner arrangement for a pressure loaded gear pump according to the present invention.

As shown on the drawings:

The pump of the present invention is indicated generally by the reference numeral ill and includes a body ii to which is integrally joined a cap portion 92, the body H being adapted to be assembled with a cover l3 having an inlet port !3a and an outlet port 5312 communicating with a pump inlet i4 and 55, respectively. It will be understood that the inlet and outlet ports I3a and 13b may be suitably formed to effect a coupling joint with appropriate conduit means associated with the pump it.

The cover 53 carries a plurality of threaded studs i! which are symmetrically arranged on a common circular centerline axis and which are adapted to be passed through the body i i. The cover i3 may be drawn up tightly with the body 5! by turning a plurality of nuts 18 on the ends of the threaded studs H, the nuts 18 being castellated in a well known manner so that a wire [9 may be employed to place the pump components in firmly locked together assembly.

Referring now to Figure 3, the body 5 i is shown as providing an irregular hollow bore providing a pumping chamber 2e formed by intersecting cylindrical bores and terminating in a shoulder 2| which also defines the limits of a pair of cylindrical bearing bores 22 and 23.

The cap portion E2 of the body H is provided with a plurality of successively decreasing counterbores which communicate with the bear- V ing bores 22 and 23, a passage 24 between the bearing bores 22 and 23 helping to establish such communication.

A liner 26 made of a suitable wear-resistant material is inserted in the pumping chamber or may be integrated with the body I! of the pump ill by being inserted before casting the body H to completely surround the teeth of a driver gear 2? and a driven gear 28 which are in intermeshing, relationship with one another and form a rotary fluid-displacement means operative in the pumping chamber 20 of the pump Hi to move fluid from the inlet M to the outlet I6. The gears 2'5 and 28 are provided with axially extending shaft portions 291; and 38a, respectively, which project toward the cap portion [2.

The shaft portion 23a of the driver gear 21 is of a suflicient length to extend into a sealing chamber formed by the progressively decreasing counterbores of the cap portion l2 and may be cooperatively related with a conventional sealing structure indicated generally by the reference character S, the structural details of which are not essential to the understanding of the principles of the present invention. The driver gear 27 including the shaft portion 29a thereof is provided with a hollow bore 3| and receives the end of a stub shaft 32 in the shaft portion 29a, the stub shaft and the shaft portion 29a being interlocked by means of interlocking spline ribs 33.

A seal cover 34 is received by thelargest counterbore portion formed in the cap portion [2 and carries a thrust ring 36 suitably concaved to provide a cooperative bearing engagement with the complementary shaped face of a shaft flange 32a.

The outermost end of the stub shaft 32 is splined as at 31 to effect a driven connection with a suitable prime mover (not shown).

A pair of relatively

fixed bushings

38 and 39 are provided each having a bearing portion receivable by the bores 22 and 23, respectively, and a radially extending end plate portion having one face abutting the shoulder 2| and the other face sealingly engaging the sides of the rotary fluid displacement means, namely the driver gear 2? and the driven gear 28. It will be noted that the bushing 33 provides a bearing for the shaft portion 29a of the driver gear 21. The driven gear 28 is provided with a shaft portion 30a which is journalled in the bushing 39. The driven gear 28 is also provided with a hollow bore which extends through the shaft portion 30a.

The cover (3 is provided with a plurality of progressively decreasing counterbores, the outermost of which indicated by the reference numeral 42 being complementary in size to the pumping chamber 20 so as to form an extension of the pumping chamber 20 when the cover I 3 and the body I l are placed in assembled together relationship.

A second counterbore 43 of smaller diameter corresponds in size to the inside diameter of the liner 26.

A pair of

movable bushings

44 and 46, each having radially extending end plate portions 54a and 45a, respectively, are telescopically received by the liner 26 and the bore 43.

One face of. the

end plate portions

44a and 46a of the

bushings

44 and 46 sealingly engages the driver gear 2! and the driven gear 28 and the other face indicated by the reference characters 44b and 46b, respectively, together with a shoulder 4"! in the cover I3 adjacent the bore 43. forms a control pressure chamber 48.

The

bushings

44 and 46 are each provided with bearing portions 440 and 460, respectively, which are integral with the

end plate portions

44a and 46a and extend axially to journal a shaft portion 2% and 30b formed on driver gear 21. and driven gear 28. The bearing portions 440 and 460 are received by generally circular bores 49 and 50, respectively, formed in the cover !3. A pair of cap members 5| each provided with flanges 5m to engage the ends of. the

bushings

44 and 46 are provided with hollow hubs 5H2 upon which is retained av coil spring 52, the opposite end of which being seated in a

counterbore

53 or 54, respectively, so as to normally spring bias and initially load the movable bushings 44' and 46 into pressure sealing engagement with the rotary fluid displacement. means. A passage 45- (Figure 2') extends from the pump outlet to the chamber 45 to admit pressurized outlet fluid thereto topressure load the movable bushings during pump operation.

As is more fully described and claimed in our copending application Serial No. 102,404,. filed June 30, 1 949 the

end plate portions

44a and 46a of the

movable bushings

44 and 46 are eccentrically disposed relative to the bearing portions 44c and 460, respectively, in order to provide uniformly distributed loading on the faces 24b and 46b of the end plate portions 44a and A generally figure eight-shaped O-ring gasket 56 is provided to axially seal the bearing portions 44c and 460 in the cover 13. The gasket 56 may be interrelated between the bearing portions and the cover in several constructional arrangements, however, in the present embodiment a counterbore 51 is provided in the cover l3'adjacent the pressure control chamber 48 to receive the gasket 56.

'Referring to Figure 4 in connection with Figure 3 it will be noted that the end plate portions of the

bushings

44 and 46 are of generally circular configuration when viewed endwise, however, since the pumping chamber is essentially figure eight-shaped because of the intersecting circular bores forming same, the

end plate portions

44a and 46a are each provided with a flattened abutment surface, the point of engagement with one another forming a joint indicated by the reference numeral 58. An exact fit is impossible to attain at the end of the mating flats and the point of intersection of the body bores and leakage from the control pressure chamber 48 to the front face of the bushings 44 must be precluded as well as leakage through the joint 58. g

In accordance with the features of the present invention, each of the

end plate portions

44a and 46a of the bushings 44 and is provided with an axially extending segmental cylindrical recess 44d and 46d which together with one another and withthe walls of the pump cover form a somewhat complexly shaped recess at the low pressure inlet end of the joint 58, the purpose of which will become manifest presently.

A generally figure eight-shaped O-ring gasket is provided to encircle the end plate portions of the bushings 44 and 4t and is received by the bore 42 of the cover l3 so as to lie adjacent the liner 20. A nubbin Bl formed integrally with the O-ring gasket 60 extends axially thereof and is received by the'complexly shaped recess aforementioned so as to substantially block the leakage path through the joint 58 at the inlet side of the pump and to the inlet side of the bushings 44.

The nubbin 6! is partially cylindrically shaped which portion is received by the recesses 44d and 46d, however, a V-shaped shelf 62 is formed therein (Figure 6) which complementally receives the radially inwardly projecting portion of the cover l3 situated at the point of inter section of the bore 43.

In Figure 5 is shown how the cover [3 as well as the

bushings

44 and 46 may be readily reversed in the pump body ll so as to permit reverse operation of the pump ill without loss of-the desirable sealing features afforded by the figure eight-shaped gasket 60 together with the.

to provide a combinedbearing-end plate-liner 63 insertable in a housing 64 and adapted to journal the shaft 66 of a gear 61 havingteeth 68 completely encircled by the liner portion thereof. V

Although various minor modifications to the preferred structural embodiments herein described may be suggested by persons skilled in the art, we wish to embody within the scope of this patent all such modifications as reasonably and properly come within the scope of Your contribution to the art.

We claim as our invention:

1. In a pressure loaded gear pump of the type having a pump body with a pumping chamber formed by a pair of intersecting cylindrical bores and having intermeshing gear type fluid displacement means rotatable in said pumping chamber, separate bushing means in each of said bores adjacent to and movable in the direction of the axis of said pump toward said fluid displacement means, said bushing means having radially extending end plates defining spaced apart face portions, one face portion of each bushing means adapted to sealingly engage said fluid displacement means and the other face portion of both of said bushing means together with the pump body defining a control pressure chamber, means to introduce pressured fluid into said control pressure chamber to load said bushing means, and an O-ring gasket between said bushing means and said pump body, said gasket having an axially extending enlarged portion, and said bushing means being recessed to receive and'position said enlarged portion between said bushing means to preclude leakagebetween the high pressure and low pressure sides of the pump.

2. In a pressure loaded gear pump of-the type having a pair of axially movable pressure loaded bushings with radially extending end plate portions having an abutment joint therebetween extending substantially between the high pressure and low pressure sides of the pump,.the improvement of a figure eight-shaped O-ring gasket to encircle the end plate portions of the movable bushings, a segmental cylindric recess defined by each of said bushings at the point of intersection of said end plate portions and together with one another forming a recess to receive sealing means therein, said O-ring gasket having an axially extending nubbin integrally formed as a part thereof and shaped complementally to said recess to fit into said recess in sealing engagement between the end plate portions of said bushings and the pump body to preclude leakage across said joint.

3., In a pressure loaded gear pump, a pum body; a pair of axially movable pressure loaded bushings therein with radially extending end plate portions having an abutment joint therebetween extending substantially between the high pressure and low pressure sides of the pump, a-recess defined by each of said bushings at the abutmentjoint of said end plate portions adjacent the pump body and'together with the body forming a complexly shaped cavity and sealing means between said bushings and said body comprising a portion shaped complementary to said cavity for reception thereby to preclude leakage across said joint. 7

4. In a pressure loaded gear pump of the type having a pump body having an inlet and an outlet with rotary fluid displacement means rotatable therein, a pair ofpressure loading bushings provided with radially extending end plate portions disposed eccentrically with respect to ina-eeamo tegrally formed bearing portions to journal and uniformly seal said fluid displacement means, said end plate portions having an abutment joint therebetween and providing a pressure loading face increasing in area towards the outlet of the pump, a recess formed in said bushings at the point of intersection of said end plate portions corresponding to the inlet side of the and sealing means between said bushings and said body including means received by said recess in said bushings to preclude leakage across said joint, said bushings being interchangeable through 1.80 to adapt said pump for reversible operation.

5. In a pressure loaded gear pump of the type having a pump body having an inlet and an outlet with rotary fluid displacement means rotatable therein, -a pair of pressure loading bushings provided with radially extending end plate portions disposed eccentrically with respect to integrally formed bearing portions to journal and uniformly seal said fluid displacement recesses, said end plate portions having an abutment joint therebetween and providing a pressure loading face increasing in area towards the outlet of the pump, a recess formed in said bushings at the point of intersection of said end plate portions corresponding to the inlet side of the pump, and an O-ring gasket between the end plate portions of the bushings and the body with an axially extending enlarged portion on said gasket and received by said recess in said bushings to preclude leakage across said joint, said bushings and said gasket being interchangeable through 180 to adapt said pump for reversible operation.

'6. In a pressure loaded gear pump of the type having a pump body having an inlet and on outlet with rotary fluid displacement means rotatable therein, a pair of pressure loading bushings provided with radially extending end plate portions disposed eccentrically with respect to integrally formed bearing portions to journal and uniformly seal said fluid displacement recesses, said end plate portions having an abutment joint therebetween and providing a .pressure loading face increasing in area towards the outlet of the pump, a recess formed in said bushings at the point of intersection of said end plate portions corresponding to the inlet side of the pump, sealing means between said bushings and said body and including means received by said recess to preclude leakage across said joint, said bushings being interchangeable through 180 to adapt said pump for reversible operation, and a cover for said pump body, said cover having an inlet port and an .outlet port, and a plurality of symmetrically disposed fastening studs whereby said cover may be rotated through 180 together with said bushings for adapting said pump for reverse operation.

7. In a pressure loaded gear pump of the type having a pump body having an inlet and an outlet with rotary fiuid displacement means rotatable therein, a pair of pressure loading bushings provided with radially extending end plate portions disposed eccentrically with respect to integrally formed bearing portions to journal and uniformly seal said fluid displacement recesses, said end plate portions having an abutment joint therebetween and providing a pressure loading face increasing in area towards the outlet of the pump, a recess formed in said bushings at the point of intersection of said end plate portions corresponding to the inlet side of the pump, an Oring gasket between the end plate portions of the bushings and the body with an axially extending enlarged portion on said gasket and received by said recess to preclude leakage across said joint, said bushings and said gasket being interchangeable through 180 to adapt said pump for reversible operation, and a cover for said pump body, said cover having an inlet port and an outlet port, and a plurality of symmetrically disposed fastening studs connecting said cover and said body whereby said cover may be rotated through 180 together with said bushings for adapting said pump for reverse operation.

8. In a pump, a pump housing including a body and a ported cover, said body and said cover together defining a pair of intersecting cylindrical bores forming a pumping chamber with an inlet and an outlet, a plurality of symmetrically arranged studs on a common circular centerline axis between said cover and said body to retain same in firm assembly in selected position for normal or reverse operation, gear type rotary fluid displacement means in said pumping chamber to move fluid from said inlet to said outlet, a pair of bushings each having a radially extending end plate portion abutting said rotary fluid displacement means, said end plate portions forming an abutment joint extending substantially between said outlet and said inlet, and a gasket having a bushing encircling portion between said end plate portions and said housing and a joint sealing portion between said outlet and said inlet at said abutment joint, said end plate portions defining oomplementally shaped axially extending registering recess portions near the point of intersection of said cylindrical bores in said housing forming a complexly shaped recess at said abutment joint to receive said joint sealing portion of said gasket, said bushings together with said gasket being reversible 1-80 in said housing for reverse operation of said pump without loss of sealing function of said gasket.

9. In a gear pump having a pair of intermeshed pumping gears, abutted bushings rotatably mounting one side of said gears, a housing for the gears slidably carrying the bushings, and a chamber in said housing vented to pump pressure and having a wall thereof defined by said bushings, whereby the bushings will be urged against the gears, the improvements of said housing having a recess surrounding the bushings, a seal ring seated in said recess and engaging the periphery of the bushings, said bushings having complementary recesses in the abutted faces thereof extending axially for an appreciable distance from the chamber defining walls thereof toward the gears, and a nubbin on the seal ring plugging said recess in said bushings to prevent leakage across the abutted faces of the bushings.

10. In a pump having a pair of rotatable pumping elements, a pair of bushings on one side of said elements ro'tatably carrying the elements, a housing slidably supporting the bushings, opposed faces on said bushings respectively engaging the elements and ccacting with the housing to define .a chamber, means venting the chamber to pump pressure for forcing the bushings against the elements, said bushings having complementary recesses in adjacent surfaces thereof, and sealing means between said housing and said bushings having a resilient plug completely confined in said recesses in said bushings to prevent leakage along adjacent surfaces.

11. In a gear pump having a pair of bushings for the gears with abutting faces and a housing providing a seal ring carrying recess surrounding the bushings, the improvements of complementary recesses in the abutting faces of the bushings extending inwardly from the seal ring carrying recess, and a seal ring in said recess including a plug completely confined in said complementary recesses for sealing against leakage along the abutting faces.

12. In a pump, a housing, a pair of meshing rotary gear impellers in said housing, a pair of bushings in the housing for the gear impellers, abutting faces between said bushings and having complementary recesses formed therein, and a sealing means between the bushings and the 1 8 housing including a nubbin plugging said complementary recesses to seal against leakage along the abutting faces of the bushings.

JOHN F. MURRAY. JAMES C. OSBORNE.

References cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,792,632 Patton Sept. 4, 1934 2,044,873 Beust June 23, 1936 2,312,655 Lauck Mar. 2, 1943 2,420,622 Roth et al. May 13, 1947 2,472,031 Wichorek May 31, 1949 2,487,732 Schanzlin Nov. 8, 1949 2,527,491 Lauck et al Oct. 31, 1950