US2696790A

US2696790A - Variable discharge pump

Info

Publication number: US2696790A
Application number: US252658A
Authority: US
Inventors: Amos E Crow
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-10-23
Filing date: 1951-10-23
Publication date: 1954-12-14
Anticipated expiration: 1971-12-14

Description

De.14,.19s4 f A. E. CRW. 2,696,790

VARIABLE DISCHARGE PUMP ATTORNEY Dec. 14, 1954 A. E. cR'ow 2,696,790

VARIABLE DISCHARGE PUMP Filed Oct. 23, 1951 4 Sheets-S1106?. 2

I N V EIN TOR. ,wos 5. mow

ATTORNEYS.

Dec. 14, 1954 A. E. CROW 2,696,790

VARIABLE DISCHARGE PUMP Filed oct. 23, 1951 4 shetssneet :5

INVENTOR. AMQS' E. c/ow Dep. 14, 1954 A. E. CROW 2,696,790

VARIABLE DISCHARGE PUMP Filed Oct. 23, 1951 4 Sheets-Sheet 4 INVENTOR. AMQS E. CROW BY umdm ammamg ATTORNEYS.

United States Patent O VARIABLE DISCHARGE PUMP Amos E. Crow, Long Beach, Calif.

Application October 23, 1951, Serial No. 252,658

8 Claims. (Cl. 10S-120) My invention relates to the eld of pumps, and more particularly to a rotary type pump which may be adjusted to var the rate of uid discharge whether the pump is operat ng or not.

,Control of the rate of fluid discharge from the pump of my invention is accomplished by varying the radial position of the impeller blades relative to the eccentrically disposed housing in which they are mounted. Various types of pumps have been devised in the past that embody the concept of radially movable blades, but the extent of movement of these blades is not controllable from outside the pump as is possible with my device. Furthermore, the movement of the impeller blades in previously available pumps is dependent on unbalanced hydrostatic pressure existing on the fluid within the connes of the device.

The present invention dilfers from the prior art devices in a number of respects, the most important of which is the control of the position of the impeller blades by an auxiliary source of hydraulic lluid under pressure, and a manually operated cam mechanism. While my invention is adapted for the normal pumping operation, it is believed that its greatest utility will be found when associated with power vehicles to serve as a brake, or means of transferring the motive power from the engine to the driving portion of the vehicle.

A disadvantage common to all present-day pumping devices employing radially movable blades lies in the increase in pressure exerted on the blades due to contact with the interior surface of the housing as the rate of impeller rotation increases. Thus, to prevent excessive wear on the blades and interior of the housing it is necessary to operate such pumps at relatively slow speeds. This disadvantage is completely eliminated by the structural design of my pump which permits operation at any desired speed without regard to increased pressure between the blades and housing due to centrifugal force.

A major object of the present invention is to provide a pump in which the impeller blades may be radially adjusted to vary the rate of fluid discharge by controlling the extent of possible outward movement of the blades, as well as the force which the blades exert on the interior face of the housing.

Another object of my invention is to supply a pump in `which the extent of outward movement of the radially movable blades may be controlled from outside the pump either when the pump is operating or not.

A further object of my invention is to furnish a pump of a relatively simple mechanical structure, that can be fabricated from commercially available materials, and operated at any desired speed without appreciably increasing the force with which the end portion of the impeller blades contact the interior surface of the housing.

Yet another object of the invention is to provide a pump having a variable rate of fluid discharge that may be utilized as a brake on a power vehicle.

Yet another object of the invention is to supply a pump in which the blades may be completely retracted within the impeller portion of the device to permit lluid flow through the pump with little or no resistance from the impeller mounted therein when the blades are thus positioned.

These and other objects and advantages of my invention will become apparent from the following description of a preferred form thereof,A and from the drawings illustrating that form in which:

ICC

Figure 1 is a longitudinal vertical cross-sectional View of my pump;

Figure 2 is a transverse vetrical cross-sectional view of the device taken on the line 2-2 of Figure l;

.Figure 3 is a `diagrammatic transverse cross-sectional view of the device illustrating the manner in which it operates;

Figure 4 is an end elevational view of one of the movable impeller blades;

Figure 5 is a perspective view of one of the assembled impeller blades;

Figure 6 is a plan view of one of the assembled impellet blades;

Figure 7 is a perspective view of one of the rack members employed in restricting movement of the blades;

Figure 8 is a fragmentary vertical cross-sectional view of the pump taken on the line 8-8 of Figure l;

Figure 9 is a fragmentary vertical cross-sectional view of the pump taken on the line 9-9 of Figure l;

Figure l() is a side elevational view of the rearward portion of a power vehicle with my pump installed on the drive shaft thereof to act as a brake;

Figure ll is a side elevational view of the rearward portion of a power vehicle with my pump installed thereon connected by gear means to the drive axles;

Figure 12 is a vertical cross-sectional view of my pump taken on the line 12-12 thereof to show the manually operated cam means that control the extent of possible movement of the impeller blades; and

Figure 13 is a horizontal cross-sectional view of the cam mechanism taken on the line 1.3-13 of Figure l2.

Referring now to Figures l, 2 and 3 for the general arrangement of my pump P, it will be seen that a shaft S rotatably supports an impeller I having radially movable blades B within the contines of a housing H. The interior of the housing H is eccentrically disposed relative to the impeller I. The rate of fluid discharge of the pump P is determined by the radial position of the blades B as may best be seen in Figure 3, which will hereinafter be discussed in detail.

Housing H is preferably an elongate tubular shell 10 that has two end pieces 11 and 12 removably mounted thereon, held in position by

bolts

13 and 14 respectively. Shell 10 has a suction opening 15 formed in one side thereof, and a fluid discharge opening 16 in the opposite side. Suction opening 15 is defined by a forked channel created by a rigid member 17 of triangular vertical cross section, with the member extending completely across the opening, as may best be seen in Figure 2. A bar 18 of substantially rectangular cross section is similarly disposed in discharge opening 16.

The interior annular vertical cross section of housing H is eccentrically disposed relative to the impeller I. The housing H is preferably formed with an oversize interior cross section that is reduced to cooperate with the rotor R by inserting two

segments

19 and 20 therein as may best be seen in Figure 2. Two segments 17a and 18a of arcuate cross section are disposed on the interior end faces of member 17 and bar 18 to complete the reduction of the interior cross section of housing H.

impeller I is formed from a cylinder rotor 22 rigidly mounted on shaft 10 and removably secured thereto by a key 23 as may be seen in Figure 2l. Rotor 22 has four equally spaced slots 24 formed therein that extend inwardly substantially one-half the radius of the rotor. Each of the slots extend the entire length of the rotor, and each slot 24 has a centrally disposed passage 24a proceeding therefrom to bore 25 through which the shaft S passes. From one end of the rotor 22 on which end piece 12 is positioned, an annular cavity 25a extends inwardly to communicate with passages 24a at its inner end (Figure 8).

Cavity 25a has a ring 27 slidably mounted therein through which shaft S extends. Ring 27 is formed with four equally spaced bores 28, each of which has a curved groove 23a extending the length thereof. Four elongate members 29 are provided that serve to regulate the outward radial movement of blades B, with the members having pinions 30 disposed in slot extensions 24a. Shafts 31 extend outwardly from pinions 30 and are journaled in bores 31a formed in the rotor 22, as may be seen in Figure 1. Shafts 32 extend outwardly from the sides of the pinions opposite those on which shafts 31 are mounted, and have transversely positioned pins 32a formed thereon that slidably engage grooves 23a. Each of the members 29 vhas a helical spring 33 encircling shaft 32 thereof, with the ends of the springs abutting against faces of the rotor 22 and the interior face of ring 27. The helical springs 33 are at all times in compression, and tend to move the ring 27 away from pinions 30, as may be seen in Figure 1.

The exterior portion of end piece 12 has abore 25h extending therethrough in which a portion of the shaft S is journaled. Bore 25a terminates on its interior end in an annular cavity 40 defined by a vertical body shoulder 41 and .horizontal interior wall surface 42 of annular configuration. The cavity 40 is in communication with a second cavity 43 that extends outwardly from the face 12a of end piece 12, and has a side wall 43a. An annular body shoulder 43h is formed at the junction of cavities 40 and 43.

Ring 27 has a tube 44 extending outwardly therefrom. A portion of the shaft S is disposed within the confines of the tube. A flange 45 is formed on the outer end of tube 44 and disposed in cavity 40, as shown in Figure 1. An annular plate 46 is provided which has a centrally disposed opening formed therein to permit mounting of the plate on tube 44. Tube 44 is held in a non-rotatable position relative to shaft S by a key 47 and plate 46 is longitudinally movable in cavity 42.

Two ball bearing assemblies 48 and 49 adapted to take a thrust load are mounted on tube 44, with the plate 46 disposed therebetween. Bearing 48 is disposed in cavities 25a and 43, with one face in contact with ring 27 and the other with plate 46. The other bearing 49 is situated in cavity 40, the two vertical faces thereof being in contact with plate 46 and the flange 45.

Longitudinal movement of ring 27 on shaft S results in rotation of pinions 30, the purpose of which will hereinafter be explained. Such longitudinal movement is accomplished by partial rotation of two spaced cams S mounted on shafts 51 journaled in bores formed in the end piece 12, as may best be seen in Figures 12 and 13. Shafts 51 have pinions 52 mounted thereon that mesh with gears 53 which are rigidly affixed to a shaft 54. The shaft 54 extends outwardly from the end piece 12, and is provided with means (not shown) for manual rotation to the desired amount.

A boss 55 is formed on end piece 12, and has a bore 56 formed therein through which the shafts 12 extend. The threaded exterior 57 of the boss is engaged by a cap 58 which has a bore formed therein through which shaft 54 extends. A fluid-tight seal is effected by tightening the cap to compress a suitable packing member 59 disposed in bore 56 to such an extent that fluid cannot pass between it and the engaging portion of the shaft.

Each of the slots 24 has a rack 60 slidably movable therein, the teeth 61 of which mesh with one of the pinions 30. Racks 60 each have a lug 62 formed on the outer portion thereof substantially normal to the longitudinal axis of the racks. The purpose of lugs 62 is to restrict the possible outward radial movement of blades B as will be explained later in detail. Thus the rack and lug structure cooperate to provide a stop that determines the maximum outward throw of the blade B with which it is associated.

The detailed structure of blade B may best be seen in Figures and 6. Each of the blades includes two

complementary members

70 and 70. As the structure of each blade member is substantially identical, only one will be described herein, with the corresponding parts of the other members identified by use of the same numerals to which a prime is affixed.

Blade member 70 includes a vertical end piece 71 from which an elongate bar 72 extends outwardly from the upper portion thereof. Bar 72 is normally disposed to the longitudinal axis of end piece 70, and has a rectangular slot 73 formed in the outer extremity thereof. A lug '74 extending outwardly from end piece 71 is situated at substantially the mid-point thereof, and extends in the same direction and disposed directly under bar 72. Lug 74 has a pin 75 extending from the extremity thereof.

The blade structure is mounted on an elongate member 76 radially movable in one of the slots 24, as may best be seen in Figures l and 2. Member 76 has

slots

77 and 77 formed therein in which lugs 74 and 74 respectively are slidably mounted, and a longitudinally extending recess 76 accommodates

bars

71 and 71. The

slots

77 and 77 `ha-ve bores 79 and -79 respectively, -extending inwardly therefrom in which the pins and 75' are slidably movably.

Bores

79 and 79 develop into

extensions

79a and 79a that extend inwardly therefrom to terminate in communication with slot 24. Each member 76 has a centrally disposed recessed portion 80 of substantially the width of slot extension 24a. The vertical cross-sectional configuration of portion 80 may best be seen in Figure 2, and includes an elongate slot S1 defined by a wall portion 82 and two

fingers

83 and 84. Slots 81 are slidably engaged by lugs 62, with the

fingers

83 and 84 defining the possible radial movement of the blades B.

The use and operation of my invention is extremely simple. As illustrated in Figure 1l, the pump is disposed on the rearward portion of a power vehicle V. Shaft S is connected by gear means, or other suitable means (not shown), to the drive shafts which actuate wheels 91. Fluid is discharged from pump outlet 16 to a conduit 92 leading to a suitable member 93 provided with an orifice A. A conduit leads from orifice A in member 93 to a leading to a suitable member 93 provided with an orifice reservoir (not shown) connected to pump suction 15 by suitable means.

When the pump P is actuated by rotation of wheels 91, fluid is discharged through conduit 92 to orifice A that offers resistance to the passage of fluid therethrough. The greater the volume of uid discharged by the pump P to the aperture A, the greater the back pressure developed on fluid within housing H to further rotation of the impeller l. Shaft S is geared to drive shafts 90, and as rotation of impeller l is lessened by the fluid back pressure set up in housing H, the rotation of drive shafts 90 and wheels 91 is lessened. Thus, with a fixed orifice A my pump may be used as an auxiliary braking mechanism to slow down the movement of the vehicle on which it is mounted.

In the event the orifice A is adjustable in size, the operator of Vthe vehicle first slows down movement of the vehicle by increasing the quantity of uid discharged through theorice, and then stops the vehicle by reducing the size of the orifice or completely closing it. The operation of my pump P as a brake on a vehicle is the same whether connected to the driving axles 90 as shown in Figure 11J or when connection to the drive shaft 95 as disclosed in Figure 10.

The vehicle V is provided with a source of hydraulic uid under pressure (not shown) that is connected by a conduit 96 to a bore 97 formed in end piece 12. Bore 97 terminates in an aperture 97a formed in cavity side wall 43a. A vacuum forming device (not shown) is also provided on vehicle V and connected by a conduit 98 to a bore 99 also formed in end piece 12 that terminates in an aperture 99a formed in cavity side 43a adjacent the interior edge thereof, as best seen in Figure 1.

When disposed in the position illustrated in Figure l, plate 46 obstructs aperture 99a. Plate 46 has bores 46a formed therein that permits fluid to flow from cavity 43 `to conduit 98 when the plate is moved inwardly from the position in which it blocks aperture 99a.

The radial position of blades B is determined by manual adjustment of the shaft 51 which actuates cams 50 to longitudinally move plate 46 within the confines of housing H. Movement of plate 46 results in concurrent longitudinal movement of ring 27 on shaft 51. As ring 27 is moved longitudinally on shaft 51, the pins 32a are rotated due to slidable engagement with grooves 28a, as may be seen in Figure 1. Rotation of pins 32a results in rotation of pinions 30, which due to their engagement with racks 69, determine the positions of lugs 62. Blades B `and member 76 may move radially in slots 24, but with the degree of movement restricted by the

fingers

83 and 84 as shown in Figures 1 and 3. Outward movement of the members 76 is restricted by the engagement of fingers 83 with the lugs 62. Inward movement of the members 76 on the rotor is restricted by the engagement of fingers 84 with the lugs 62, as may be seen in Figure 1. The lugs 62 merely determine the possible degree of inward and outward radial movement of members 76 relative to the supporting rotor.

After adjustment of the cam Sil to limit possible outward radial throw of blades B, hydraulic uid is admitted intopump P from conduit 96. Blades B are immediately forced outwardly until fingers 83 contact lugs 62. Hydraulic iiuid passes through bores '79 and 79 and bore

extensions

79a and 79a to contact the extremities of pins 75 to force the

blade end pieces

71 and 71 into lluid sealing contact with housing end pieces 11 and 12 respectively.

Blades B are in the fully extended position for the partlcular setting of cam 50 prior to engaging segment 19, and thereafter retract until they are flush with the surface of rotor 22 when engaging segment 20. The quantity of h ydraulic fluid required to actuate the blades is substantlally constant, for as one blade is moving outwardly, another blade is moving inwardly due to the offsetting of the interior of housing H.

When it is desired to reduce the quantity of iluid discharged from the pump, a portion of the hydraulic fluid supplied under pressure through tube 96 is permitted to discharge through tube 98 to the reservoir (not shown) connected to pump suction 15. Cam 50 is then actuated to restrict the possible outward throw of bladesvB until the rate of fluid discharge from the pump of my invention is reduced the desired amount.

From experience it has been found that my invention may be used advantageously in a closed hydraulic circuit where there is fluid ilow but from a source other than my pump. Under these conditions it is desirable that the blades B offer a minimum of resistance to fluid flow, which is accomplished by rotating cams 50 until the blades B are completely retracted into the rotor 22. The shaft S at all times rotates the rotor 22, but when the blades are fully retracted, little or no pumping action results. When it is desired to pump luid in such a closed hydraulic circuit, such as when used as a brake (shown in either Figures l0 or ll) the cams 50 are rotated the desired amount, and iluid under pressure admitted through tube 96 moves the blades B outwardly.

Although the adjustable discharge pump herein shown and described is fully capable of achieving the objects and providing the advantages hereinbefore mentioned, it is to be understood that it is merely illustrative of the presently preferred embodiment of my invention, and that I do not mean to limit myself to the details of construction herein shown other than as defined in the appended claims.

I claim:

1. A variable discharge rotary pump which includes: a cylindrical housing with uid discharge and suction openings formed therein; a rotor disposedin said housing, said rotor having a plurality of radially disposed slots formed therein, and said slots communicating with a centrally disposed passage formed in said rotor; a plurality of blades, each of which is formed with two interlocking portions that may move longitudinally relative to one another; a shaft rotatably supported in said housing onwhich said rotor is mounted, saidshaft and rotor being eccentrically arranged relative to said housing; a plurality of rigid members movably mounted in said slots two portions that are slidably connected to one another for longitudinal movement, each of said portions being formed with an inwardly extending end piece from which a pin projects; a plurality of rigid members movably mounted in said slots capable of radial movement relative to said rotor, with one of said blades being disposed along the outer longitudinal edge of each of said members and with two bores being formed on the ends of each of said members, which bores are in communication with said passage and slidably receive said pins; a plurality of radially movable stops, each of which is disposed in one of said slots, with each of said stops including a rigid portion that engages one of said members after said member has moved radially outwardly a predetermined distance relative to said rotor; manually operated cam means that concurrently regulate the radial positions of all of said stops; means to introduce hydraulic iluid into said passage to force said members outwardly into contact with said stops, with a portion of said hydraulic fluid flowing through said bores to engage said pins and force the ends of said blade portions into fluid-sealing contact with the interior surface of said housing; and vacuum means for withdrawing said hydraulic fluid from said passage and bores to cause said blade portions to move inwardly a predetermined longitudinal distance toward one another, with said blades and supporting members moving radially inward relative to said rotor to retracted positions.

3. A variable discharge rotary pump which includes: a cylindrical housing with fluid discharge and suction openings formed therein; a shaft; a cylindrical rotor mounted on said shaft, which shaft and rotor are rotatably supported in said housing and eccentrically arranged thereto, said rotor having aI plurality of parallel radially disposed slots formed therein, and said slots communicating with a centrally disposed passage formed in said rotor; a plurality of blades supported for radial movement in said slots, each of said blades including two interlocking portions that may move longitudinally relative to one another; a plurality of radially movable stops, a portion of each being disposed in one of said slots, with each stop preventing further outward radial movement of one of said blades after said blade has moved outwardly a predetermined distance relative to said rotor; manually operated cam means that concurrently regulate the radial positions of all of said stops; hydraulic means to force all of said blades radially outward until further movement is prevented by said stops, and to move all of said blade portions longitudinally into fluid-sealing contact with the interior surface of said housing; and vacuum means to move said blades radially inward relative. to

capable of radial movement relative to said rotor, with each of said members so supporting one of said blades that said interlocking portions may move longitudinally but not radially relative to said supporting member; a plurality of radially movable stops, each of which is disposed in one of said slots, with each of said stops including a rigid portion that engages one of said members after said member has moved outwardly a predetermined distance relative to said rotor; manually operated cam means that concurrently regulate the radial positions of all of said stops; means to introduce hydraulic fluid into said passage to force said members outwardly into contact with said stops, with a portion of said iluid flowing through passage means extending outwardly from said passage to contact said blade portions and force the ends thereof into lluid sealing contact with the interior surface of said housing; and vacuum means for withdrawing said hydraulic iluid from said passage and passage means to cause said blade portions to move inwardly toward one another a predetermined longitudinal distance, with said blades and supporting members moving radially inward relative to said rotor to retracted positions.

2. A variable discharge rotary pumpwhich includes: a cylindrical housing with fluid discharge and suction openings formed therein; a shaft; a rotor mounted on said shaft, which shaft and rotor are rotatably supported in said housing and eccentrically arranged relative thereto, said rotor having a plurality of parallel radially disposed slots formed therein, and said slots communicating with a centrally disposed passage formed in said rotor; a plurality of elongated blades, each of which is formed from said rotor, and to move said blade portions inwardly relative to one another to a predetermined retracted position.

4. A variable discharge rotary pump which includes: a cylindrical housing with iluid discharge and suction openings formed therein; a shaft rotatably supported in said housing; a rotor rigidly mounted on said shaft which shaft and rotor are rotatably supported within the confines of said housing and eccentrically disposed relative thereto; a plurality of blades, each of which is formed of two portions with each blade being supported from said rotor for radial and longitudinal movement relative thereto; a plurality of adjustable stops mounted on said rotor, each of which is operatively associated with one of said blades, the position of each stop controlling the maximum outward throw of said blade with which it is associated; manually operated means that concurrently adjust all of said stops to identical radial positions relative to said rotor; means to subject said blades to hydraulic pressure whereby said blades move outwardly relative to said rotor until further movement is prevented by said stops, said blade portions being so constructed that they move relative to one another to engage the interior surface of said housing with a movable fluid-tight seal; means to regulate the intensity of said hydraulic pressure to control the pressure with which said blades engage the interior surface of said housing; and means to subject said blades to a vacuum to withdraw said blades to retracted positions relative to said rotor.

5. A variable discharge rotary pump which includes: a cylindrical housing with fluid discharge and suction openings formed therein; a shaft; a cylindrical rotor mounted on said shaft, which shaft and rotor are rotatably supported in said housing and eccentrically disposed relative thereto; a plurality of blades, each of which is formed of two portions, with each blade being radially and longitudinally supported on said rotor; a plurality of adjustable stops, each of which is operatively associated with one of said blades, the position of each stop controlling the maximum outward throw of said blade with which it is associated; manually operated means that concurrently adjust all of said stops to identical positions relative to said shaft; means to subject said blades to hydraulic pressure whereby said blades move outwardly relative to said rotor until further movement is prevented by said stops, said blade portions being so constructed that they move relative to one another to engage the interior surface of said housing with a movable fluid-tight seal; means to regulate the intensity of said hydraulic pressure to control the pressure with which said blades engage the interior surface of said housing; and means to subject said blades to a vacuum to withdraw said blades to retracted positions relative to said rotor.

6. A variable discharge rotary pump which includes: a cylindrical housing with uid discharge and suction openings formed therein; a shaft; a cylindrical rotor mounted on said shaft, which rotor and shaft are rotatably supported in said housing and eccentrically arranged relative thereto, a plurality of blades rotatably supported within the confines of said housing on said rotor, with each of said blades including two portions that may move radially and longitudinally; a plurality of adjustable stops operatively associated with said blades that determine the maximum radial throw of said blades; manually operated means that concurrently adjust all of said stops to positions where the maximum radial throw of said blades are identical; means to subject said blades to hydraulic pressure whereby said blades move radially outward the maximum distance permitted by said stops, said blade portions being so constructed that they move relative to one another to engage the interior surface of said housing with a movable Huid-tight seal; means to regulate the intensity of said hydraulic pressure to control the pressure with which said blades engage the interior surface of said housing; and means to subject said blades to a vacuum to withdraw said blades to retracted positions relative to said rotor.

7. A variable discharge rotary pump which includes: a cylindrical housing with fluid discharge and suction openings formed therein; a first shaft; a cylindrical rotor mounted on said shaft, which rotor and shaft are rotatably supported in said housing and eccentrically disposed relative thereto, said rotor having a centrally disposed longitudinally extending passage formed therein from which a plurality of radial slots extend, with inwardly extending passages leading from said slots to said longitudinal passage; a plurality of blades, each of which is formed of two interlocking portions that move longitudinally relative to one another; a plurality of rigid members movably mounted in said slots capable of moving radially relative to said rotor, with each of said members so supporting one of said blades that said portions thereof may move longitudinally but not radially relative to said supporting member; a plurality of radially movable stops formed with toothed racks, each stop being slidably disposed in one of said inwardly extending passages; a plurality of pinions, each of which is disposed in one of said inwardly extending passages and engages one of said racks; a plurality of second shafts supporting said pinions on the ends thereof, with said second shafts rotatably supported in said rotor; a plurality of pins, each of which is transversely disposed on the outwardly extended end of one of said second shafts; a plate longitudinally movable on said first shaft, said plate being formed with a plurality of curved and slotted bores, and said slotted bores being slidably engageable with one of said pins; manually operated cam means which when actuated moves said plate longitudinally on said first shaft to rotate said pinions, and radially moves all of said stops the same distance; means to introduce hydraulic uid into said passageto force said members outwardly into contact with said stops, with a portion of said Huid flowing through passage means extending outwardly from said centrally disposed passage to contact with blade portions, forcing the ends of said portions into huid-sealing contact with the interior surface of said housing; means to control the pressure exerted by said hydraulic Huid regulating the intensity with which said blades are urged into contact with the interior surface of said housing; and vacuum nieans to withdraw said hydraulic Huid from said passage and passage means, causing said blade portions to move a predetermined longitudinal distance toward one another, and said blades and supporting members to move radially inward relative to said rotor to retracted positions.

8. A variable discharge rotary pump which includes: a rotor; a shaft on which said rotor is mounted; a housing in which said rotor and shaft are rotatably supported and eccentrically arranged relative thereto; a plurality of blades mounted on said rotor in spaced relationship, each of which is formed from two portions that are so const ructed that they may move both radially and longitudinally relative to said rotor; manually adjustable means which restrict the outward and inward radial movement of said blades relative to said rotor; hydraulic means to move said blade portions longitudinally and radially outward from said rotor whereby said blade portions contact the interior surfaces of said housing; means to regulate the intensity of the force applied to said blade portions by said hydraulic means; and vacuum means to Withdraw said blade portions inwardly toward said rotor to retracted positions determined by the location of said adjustable means at the time of said withdrawal.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 732,671 Andrews June 30, 1903 741,617 Bogart Oct. 20, 1903 939,911 Heimann et al Nov. 9, 1909 968,859 Kruger Aug. 30, 1910 1,393,802 Lupton, Jr Oct. 18, 1921 1,846,557 Imshenetsky Feb. 23, 1932 2,175,413 Sharar Oct. 10 1939 2,498,826 Ruona Feb. 28, o 2,523,543 Smith Sept. 26, 1950 2,555,678 Cornwell June 5, 1951