US2781730A

US2781730A - Implement pump

Info

Publication number: US2781730A
Application number: US316231A
Authority: US
Inventors: Carleton H Newmier
Original assignee: Thompson Products Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1952-10-22
Filing date: 1952-10-22
Publication date: 1957-02-19
Anticipated expiration: 1974-02-19

Description

Feb. 19, 1957 c. H. NEWMIER IMPLEMENT PUMP 3 Sheets-Sheet; 1

Filed Oct. 22, 1952 .Zizventarnfarlelozz J-Y. Mai/Hie;

Feb. 19, 1957 I c. H. NEWMIER 2,781,730

IMPLEMENT PUMP Filed 001;. 22, 1952 v 3 Sheets-Shet 3 United States Patent fice 2,781,730 Patented F eb. 19, l

2,781,730 IMPLEMENT PUMP Carleton H. Newmier, Cleveland; Ohio, assignor to Thompson Products, Inc., Cleveland, Ohio, a corporation of Ohio Application October 22, 1952, Serial No. 316,231

I Claims; (Cl. 103-426) This invention relates generally to gear pumps and more particularly to a positive displacement high pres sure gear pump having movable bushings provided; with a radially extending sealing face engaging the sides of the gears and including recesses formed in the sealing face at the inlet side of the pump to improve the filling characteristics of the gears as well as recesses at the discharge side of the pump to reduce the velocity of the discharged liquid, to reduce the fluid carried around in the pump and to minimize liquid flow reversal and to. re-' duce hydraulic shock losses by directing discharge fluid tangentially with respect to the gears.

According to the principles of the present invention; a pump is provided having rotary fluid displacement means which in one preferred embodiment may take the form of a pair of meshing rotary gears. The gears are journalled in bushings each having a radially extending seal ing face engaging the sides of the gears. The casing of the pump provides an inlet on one side of thegear mesh and an outlet on the other side of the gear mesh. of the sealing faces of the bushings is provided with a recess extending into the gear mesh on the inletside of the mesh but terminating at the root diameter of the gears, thereby to provide an inlet path to. the spaces or voids between the gear teeth. The additional inlet path thus provided greatly improves the filling characteristics of the gears and the operation of a pump so equipped will be characterized by a corresponding increase in pumping efficiency. 7 V

The sealing face of each of the bushings is further provided with a recess extending into the gear meshon the outlet side of the gear mesh but terminating 'at the root diameter of the gears, thereby providing passage means which will be etfective in reducing the velocity or the displaced fluid at the vicinity of the gear mesh and which will also be effective to minimize the carrying around of fluid by the gears. I The sealing face of each of the bushings is flirt-her provided with a recess on the outlet side of the mesh which diverges away from the gear mesh in generally tangentially relationship with respect to the gears. Such recess lies adjacent the gear teeth but terminates at the root diameter of the gears, thereby providing a tangential flow path at the outlet which tends to minimize flow reversal and which is effective in reducing hydraulic shock losses.

In high pressure gear pumps of the type described herein; one set of bushings on one side of the gears is made movable with respect to the casing so that the bushings may b'e pressure loaded into sealing engagement with the sides of the rotary gears or rotary fluid displacement means. In order to eliect pressure loading of the mov-' able bushings, a pressure control chamber is provided between a radially extending pressure face providedi o'n the bushings and the casing. V

Accoifding to the principles of the present invention; the pressure control chamber is formed in a figure-8 shaped bore located behind the radially extending tiressure face of the movable bushings. A flat figures-shaped plate springis received in the pressure control chamber and continuously biases the movable bushings axially so as to initially load the bushings into sealing engagement with the sides of the rotary fluid displacement means. Means are provided to communicate pump discharge pressure to the pressure control chamber so that the movable bushings will be pressure loaded during operation of the Pu p. t

It is an object of the presentinvention. to provide a positive displacement pump having improved inlet and discharge characteristics. 7 t

Another object of the present invention is, to provide a positive displacement gear pump having means iO il'Il? prove the filling characteristics of the gears at the inlet side of the pump. v

Agfurtherobject of the present invention is to provide a rotary gear, pump in which means are included to reduce ,thevelfocity of the displaced liquid at the vicinity of the gear mesh. 7

Yet another object of the present invention is to provide a rotary gear pump in which means are provided to reduce the fluid carried around in the pump. H a

A further object of the present invention isto'p'rovide aprota'ryfgear pump having means provided adjacent the gear mesh. on the discharge side of the pump to mini-', niize flow reversal of the pump fluid.

still further object of the present invention is to prdvide a rotary gear pump wherein hydraulic shock losses at the vicinity of the gear mesh on the discharge side of the pump are reduced by directing the fluid tangentially away from the gear mesh.

7 Another object of the present Invention is to provide improved means for initially loading movable bushings in a high pressure gear pump.

I 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 dc: tailed description which follows and the accompanying sheets of drawings in which a preferred structural em bodiment of a high pressure gear pump incorporating the principles of the present invention is shown by way of illustrative example only.

On the drawings: 7 A V Figure 1 is an end elevational view with parts V broken away and with parts shown in cross section and showing a pump provided in accordance with the principles of th'epres'ent invention; p

Figure 2 is a cross-sectional view with parts shown in elevation of the pump shown in Figure 1;

Figure 3 is a cross-sectional view with parts removed and with parts shown in elevation taken substantially on line III--III of Figure 1; I

Figure 4 is a fragmentary cross-sectional view showing in elevation the sealing facesof the movable bushings provided in accordance with the principles of the present invention and taken generally on theline IV IV of Figure 2; t

Figure 5 is a fragmentary cross-sectional view showing in elevation the sealing faces of the bushings utilized in accordance with the principles of the present invention and taken generally on the line VV of Figure 2;

Figure is an enlarged cross-sectional view showing additional details of construction and the structural relationship between the sealing faces provided on the bush-. ings of the present invention and the meshing gears of the pump;

, Figure. 7 is a cross-sectional view taken generally on lines VIL-VII of Figure 2 and with parts removed to show additional details of construction; and m I Figure 8 is an enlarged end elevational View of the plate spring provided in accordance with the principles of the present invention.

As shown on the drawings:

Although the principles of the present invention are generally applicable to various types of positive displacement pumps, the preferred embodiment herein described by way of illustrative example comprises a high pressure gear pump indicated generally at and comprising a casing 11 closed by a cover 12 and held in firm assembly therewith by a plurality of fasteners 13.

The casing 11 is provided with an inlet 14 and an outlet 16. A pumping chamber 17 is provided between the inlet 14 and the outlet 16 and receives rotary fluid displacement means which, in the present embodiment, take the form of rotary gears including a driver gear 18 and a driven gear 19. Each of the

gears

18 and 19 is provided with a plurality of circumferentially spaced teeth 20 :hich mesh as at 21. The teeth of the gears extend radially inwardly and terminate at the root diameter shown at 22.

As is customary in gear pump operation, it will be understood that a space or void 23 provided between each pair of teeth 20 is filled with a pumping fluid at the inlet of the pump whereupon the fluid is carried to the outlet side of the pump and is forced from the space 23 by the intermesh of the gear teeth 20.

Referring now more particularly to Figure 2, it will be noted that the casing 11 includes a reduced bore 24 located opposite the driver gear 18 and a reduced bore 26 located opposite the driven gear 19. A bushing 27 is received in the bore 24 and a bushing 28 is received in the bore 26 to journal, respectively, the stub shaft portion 29 of the driver gear 18 and the stub shaft portion 30 of the driven gear 19.

Each of the

bushings

27 and 23 is provided with a radially extending

flange portion

31 and 32 respectively which is received in the pumping chamber 17 of the casing 11.

The

flanges

31 and 32 of the

bushings

27 and 28 are generally circular in configuration, however, each is characterized by a chordal section providing a flat mating abutment surface forming a joint 33 which is clearly shown in Figures 2 and 5 and which extends generally across the pump between the inlet side and the discharge or outlet side thereof.

Each of the

flanges

31 and 32 of the

bushings

27 and 28 provides a flat sealing

face

34 and 36 respectively which abut the side faces of the driver gear 18 and the driven gear 19.

The cover 12 is provided with a bore 37 which like the pumping chamber 17 in the casing 11 is generally figure- 8-shaped in configuration. An additional recess 38 is provided in the cover 12 at the point of abutment with the casing 11 to receive a seal ring 39.

A reduced bore 40 is provided in the cover 12 opposite the driver gear 18 and a reduced bore 41 is provided in the cover 12 opposite the driven gear 19. Each of the

bores

40 and 41 receives a

movable bushing

42 and 43 respectively and each bushing is provided with a radially extending

flange

44 and 46, respectively, providing a radially extending sealing

face

47 and 48 respectively to engage the side faces of the driver gear 18 and the driven gear 19 and a radially extending

pressure face

49 and 50 respectively which faces are spaced from the

sealing faces

47 and 48 and which are located on the opposite side of the

flanges

44 and 46.

The figure-S-shaped bore 37 together with the pumping chamber 17 receives the

flanges

44 and 46 of the

bushings

42 and 43 and slidingly engage the

peripheral surfaces

51 and 52 respectively so as to journal the shaft extension 53 of the driver gear 18 and the stub shaft 54 of the driven gear 19 in the casing 11 and the cover 12.

The components of the pump thus far described are so proportioned that the bore 37 provided in the cover 12 together with the

bushings

42 and 43 forms a pres- 4 sure control chamber 56 behind the

flanges

44 and 46 so that the pressure faces 49 and 50 form one wall of the pressure control chamber 56.

The cover 12 is provided with an opening 57 which passes the shaft extension 53 of the driver gear 18 and a connection may be made with the shaft extension 53 to a prime mover (not shown) on the free end of the shaft extension 53 as shown at 58. Any suitable shaft seal is provided between the cover and the shaft and in this illustrative embodiment the opening 57 is provided with an annular groove 59 receiving a seal ring 60 providing a sealing action between the cover 12 and the shaft extension 53. A suitable seal ring 61 is also provided between each of the

bushings

42 and 43 and the cover 12.

As shown in Figure 4, the

flanges

44 and 46 of the

bushings

42 and 43 are generally circular in configuration, however, each is provided with a chordal section providing a flat abutment surface and forming a joint indicated at 65 extending across the pump between the inlet and outlet sides thereof. Thus, the abutting

bushings

42 and 43 provide sealing

surfaces

47 and 48 which, together, describe a figure-8 configuration.

A figure-S-shaped flat plate spring 62 is located in the pressure control chamber 56 and exerts a continuous biasing force between the cover 12 and the

bushing

42 and 43 so as to initially load the

bushings

42 and 43 into sealing engagement with the driver gear 18 and the driven gear 19. Referring particularly to Figures 7 and 8, it will be noted that the plate spring 62 comprises a first loop 63 and a second loop 64 each of the loops including a plurality of circumferentially spaced axially offset tangs 63a and 64a. The tangs 63a and 64a are preferably struck out from the peripheral portions of the

loops

63 and 64. By making the plate spring 62 out of a resilient material such as a springy metal, the inherent resilience of the tangs 63a and 64a will produce a continuous biasing thrust force when the plate spring 62 is confined between the pressure faces 49 and 50 of the

bushings

42 and 43 and the opposite wall of the pressure control chamber 56 provided by the casing 12.

When the pump is in operation, it will be apparent that an increased biasing force is necessary to adequately seal the sides of the gears and, accordingly, a passage way 66 is provided to place the pressure control chamber 56 in communication with the outlet 16 of the pump 10 so that discharge pressure will act on the pressure faces 49 and 50 and will pressure load the

bushings

42 and 43 axially into sealing engagement with the driver gear 18 and the driven gear 19.

In accordance with the principles of the present invention, means are provided to improve the filling characteristics of the gears. As shown in Figure 5, the sealing face 34 of the bushing 27 is provided with a recess 70 and the sealing face 36 of the bushing 28 is provided with a recess 71, the two

recesses

70 and 71 lying adjacent to one another at the abutment joint 33 and extending inwardly towards the gear mesh 21 of the driver gear 18 and the driven gear 19 on the inlet side of the pump 10.

As is shown in Figure 3, the

recesses

70 and 71 of the

bushings

27 and 28 communicate with the inlet 14 and thereby provide a flow passage to the spaces 23 between the gear teeth 20.

The sealing faces 47 and 48 of the

bushings

42 and 43 are also provided with

recesses

72 and 73 respectively located at the abutment joint 65 and communicating with the pump inlet 14 to provide additional flow paths to the spaces or voids 23 between the gear teeth 20. As will be understood by making reference to Figure 6, each of the

recesses

70, 71, 72, 73 extend radially inwardly of the outer periphery of the sealing faces provided by the

bushings

27, 28, 42 and 43, however, the recesses terminate at or short of the root diameter 22 of the driver gear 18 and the driven gear 19. Preferably the recesses terminate at the root diameter to afford optimum operating efiiciency.

The present invention also contemplates the provision assists statin -t reduce the velocity or the tunssues at the gear mesh 21 on the outlet side of tfie'punip; To ac-1;

eor'nplis hthis end, each of these'aling faces 47 and48' of the

bushings

42 and 43 is provided with a recess 74' and respectively which extend radially. ihwafdly from the periphery of the sealing faces 47 and 48 at the vicinity of the abutment joint 65 but which terminate at or short of the root diameter 2 2 of the driver gear 18 and the driven gear 19. I As will be understood-upon referring to Figure 3,- the

recesses

74 and 76 communicate with the outlet 16 and form together with one another a passage way extending into the mesh 21 of the gears s o as toreduce the velocity of theffluid displaced at the mesh and to thereby minimize the carrying around of fluid by the gears. v

The present invention further contemplates the provisionof' means to reduce hydraulic shock losses by directing the fluid away from the gear mesh 21 tangentially; In, order to effect this function, eachof the sealing faces 47 and- 48

provi'ded onthe bushings

42 and 43 is recessedasat 77 and 78 respectively.

The

recesses

77 and 78 are arranged in generally tangential alignment relative to the respective gear members and communicate with the recesses 74- and 7 6, respectively, as at 79 and 80. There is thus provided a; tangential flow path at the outlet which greatly reduceshydraulic shock losses at the gear mesh 21 and which minimizes the reversal of how of the pumping fluid by directingthe d'lSI 6 placed at theflmesh and to minimize the carrying around of fluid by the gears, said face having a' second recess formed therein on the outlet side of the mesh angular-1y intersecting and communicating with said first recess and diverging away from the mesh generally tangential to each of the gears and lying adjacent the gear teeth but terminating at the root diameter of the gears and providinga tangential flow path insaid bushing means at the outlet minimizing flow reversal and reducing hy-' draulic shock losses. 7

4. In gear pump, a pair of meshing rotary gears, bushing means having a sealing face engaging the of the gears, and means providing an inlet on one side of the gear mesh and an outlet on the other side of the gear mesh, said face of said bushing means having a first recess formed therein extending from said inlet into the mesh on the inlet side of the mesh but terminatihg at the root diameter of the gears to provide ah inlet path in said bushing means adjacent to the spaces be? tween the gear teeth, said face having a sec'ond recess" formed therein extending from said outlet into the gear mesh on the outlet side of the mesh but terminating at the root diameter of the gears to reduce the velocity of the fluid displaced at the mesh to minimize the placed fluid tangentially relative tothe driver gear 1-8 m and the driven gear 19.

Although various minor structural modifications might be suggested by those versed in the art to the preferred embodiment herein described by way of illustrative example only, it should be understood that I wishto embody within the scope of the patent warranted hereon all such modifications as reason'ablyand properly come 'within the scope of my contribution to the art.

I claim as my invention:

1. In a gear pump, a pair of meshing rotary gears, bushing meansin sa'id pump having formed thereon a sealing face engaging the sides of the gears and means providing an inlet on one side of the gear mesh and an outlet on the other side of the gear mesh, said face of said bushingmeans having a recess formed therein on the outlet side of the mesh diverging away from the mesh generally tangential to each of the gears and lying adjacent the gear teeth but terminating at the root diameter of the gears and providing a tangential flow path in said bushing means at the outlet minimizing flow reversal and reducing hydraulic shock losses.

2. In a gear pump, a pair of meshing rotary gears, bushing means having a sealing face engaging the sides of the gears, and means providing an inlet on one side of the gear mesh and an outlet on the other side of the gear mesh, said face of said bushing means having a first recess formed therein extending from said inlet into' the mesh on the inlet side of the mesh but terminating short of the root diameter of the gears to provide anvinlet path in said bushing means laterally adjacent to thespaces between the gear teeth, said, face having a second recess formed therein on the outletside of the mesh diverging away from the mesh generally tangential to each of the gears and lying adjacent the gear teeth but terminating at the root diameter of the gears and providing a tangential flow path in said bushing means at the outlet minimizing flow reversal and reducing hydraulic shock losses.

3. In a gear pump, a pair of meshing rotary gears, bushing means in said pump having formed thereon a sealing face engaging the sides of the gears, and means providing an inlet on one side of the gear mesh and an outlet on the other side of the gear mesh, said face of said bushing means having a first recess formed therein extending from said outlet into the gear mesh on the outlet side of the mesh but terminating at the root diameter of the gears to reduce the velocity of the fluid discarrying around of fluid by the gears, said face having a third recess formed therein on the outlet side of the mesh angularlyintersecting andcommunicating: with said second recess and diverging away from the mesh gen? erally' tangential to each of thegears and lying adjacentj thegear teeth but terminating at the root diameter of the gears and providing a tangential flow path in said bushing means at the outlet minimizing flow reversal and reducing hydraulic shock losses. v I N 5. A pump having a casing providing an inlet, aii outlet and a pumping chamber, therebetween, rotary fluid displacementmeans in said pumping chamber pumping fluid from the inlet to the outlet, said casing having a reduced bore at one side of said pumping chamber, movable bushings received in said reduced bore journalling said rotary fluid displacement means and being provided with a radially extending sealing face engaging the rotary fluid displacement means, said bushings being provided further with a radially extending pressure face spaced from said sealing face and forming together with the casing a pressure control chamber behind said movable bushings, means providing communication between the pump outlet and the pressure control chamber to pres sure load the movable bushings into sealing engagement with the rotary fluid displacement means when the pump is operating, and a flat plate spring conforming generally in configuration with said pressure face and received in said pressure control chamber, said plate spring bot tomed against said casing, said spring having spaced ap'erturestformed therein for receiving and passing the journalling portions of said movable bushing and having abutment surfaces thereon for engaging and exertinga continuous biasing force against said radially extending pressure face to initially load said movable bushings into sealing engagement with the rotary fluid displacement means.

6. In a gear pump, a casing providing a generally figure-fi-shaped pumping chamber, a cover for said casing, a driver gear in one recess portion of said figure-8- shaped pumping chamber and a driven gear in the other recess portion of said figured-shaped pumping chamber, said cover having a. reduced bore opposite each of said gears, and a bushing in each of said reduced bores, each bushing having a radially extending sealing face engaging a corresponding one of said gears, and a radially extending pressure face spaced from said sealing face, a figureh-shaped bore formed in said cover and providing a figured-shaped pressure control chamber behind said pressure face of said bushings, means supplying pump discharge pressure to the pressure control chamber to load the bushings into sealing engagement with the gears when the pump is operated, and a figure-S-shaped plate spring in said pressure control chamber bottomed against said cover and having abutment surfaces engaging and exerting a continuous biasing force against said bushing to initially load said radially extending pressure face of each said bushings into sealing engagement with said gears.

7. In a pump, a housing having an inlet and an outlet and providing a figure 8-shaped pumping cavity, and a pair of end plate members for said cavity in said housing, each said end plate member having a pressurereceiving back surface forming together with means including a portion of said housing a figure 8-shaped pressure control chamber, means placing said pressure control chamber in pressure communication with said outlet to pressure-load said end plate members towards the cavity with pump-generated pressure during operation of the pump, and a flat figure S-shaped plate spring in said pressure control chamber operatively interposed between said pressure-receiving back surface of each said end plate members and said housing to mechanically preload the end plate members towards the cavity with a predetermined minimum biasing force, thereby insuring priming of the pump and pressurization of said pressure control chamber.

8. In a pump, a housing having an inlet and an outlet and providing a pair of overlapping bores providing a pumping cavity for rotary intermeshing gears, a plurality of end plate members for said cavity in said housing, each having a sealing face for a corresponding bore of said cavity adapted to engage and seal against an adjoining said face of a corresponding gear, contacting mating flat surfaces between a pair of said end plate members, said flat surfaces being disposed adjacent an area of intermesh of the teeth of the gears, and means to reduce hydraulic shock loss comprising a recess formed in each of said end plate members on the outlet side thereof and extending through said sealing surface at the periphery thereof exteriorly of the root diameter of the gear teeth from the outer end of a corresponding one of said contacting mating surfaces tangentially to form a tangential flow path interconnecting a selected number of spaces between the adjoining gear teeth for minimizing reversal of flow of pumping fluid by directing displaced fluid at outlet pressure away from the area of intermesh tangentially.

9. In a pump, a housing having an inlet and an outlet and providing a pair of overlapping bores providing a pumping cavity for rotary intermeshing gears, a plurality of end plate members for said cavity in said housing, each having a sealing face for a corresponding bore of said cavity and each adapted to engage and seal against an adjoining side face of a corresponding gear, contacting mating flat surfaces between a pair of said end plate members disposed adjacent an area of intermesh of the teeth of the gears, means to reduce the velocity of the fluid displaced at the area of intermesh comprising a first recess formed in each of said end plate members on the outlet side thereof and extending from said contact mating flat surfaces into said sealing face but terminating at or short of the root diameter of the gear teeth, and means to reduce hydraulic shock loss comprising a second peripheral recess formed in each of said end plate members on the outlet side thereof and extending through said sealing surface exteriorly of the root diameter of the gear teeth from the outer end of a corresponding one of said contacting mating surfaces tangentially; to form a tangential flow path interconnecting a selected number of spaces between the adjoining gear teeth to minimize reversal of flow of pumping fluid by directing displaced fluid at outlet pressure away from the area of intermesh tangentially.

10. A gear pump, comprising, a casing having an inlet, an outlet, and a pumping chamber therebetween, rotary gears in said pumping chamber moving fluid from the inlet to the outlet, and a pair of bushings on opposite sides of said pumping chamber journaling said gears in said casing and each being provided with a radial extending sealing face engaging the sides of the gears, each bushing of each respective pair of bushings having a mated flat abutment surface and together forming a joint between the bushings, each bushing having a recess formed in said sealing face at said flat abutment surface lying adjacent the gear teeth of the gears, each of said recesses terminating hort of the root diameter of the gears, said recesses being formed adjacent the inlet of the pump and communicating therewith to provide a flow path in said bushings from the inlet to the spaces between the gear teeth of the gears, thereby to improve the filling characteristics of the gears, means to reduce the velocity of the fluid displaced at the area of intermesh comprising a first recess formed in the outlet side of each of said end plate members and extending from said mated flat abutment surface into said sealing face but terminating at or short of the root diameter of the gear teeth, and means to reduce hydraulic shock loss comprising a second peripheral recess on the outlet side of each of said end plate members extending through said sealing surface exteriorly of the root diameter of the gear teeth from the outer end of a 1 corresponding one of said mated fiat abutment surfaces tangentially to form a tangential flow path interconnecting a selected number of spaces between the adjoining gear teeth to minimize reversal of flow of pumping fluid by directing displaced fluid at outlet pressure away from the area of intermesh tangentially.

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