US2935952A - Pressure booster or de-booster - Google Patents

Description

H. E. ROSE May 10, 1960 PRESSURE BOOSTER OR DIE-BOOSTER 2 Sheets-Sheet 1 Filed June 12, 1957 lllililllJ INVENTOR. HOWARD E. ROS

HQ'MM ATTORNEY6.

May 10, 1960 H. E. ROSE PRESSURE BOOSTER OR DE-BoosTER Filed June 12, 1957 v 2 Sheets-Sheet 2 INVENTOR. HOWARD E. ROSE.

TOBNE United States The present invention relates generally as indicated to a pressure booster or de-booster and more particularly to a device which is in the form of a motor-pump having a motor inlet port into which fluid under pressure is delivered and having a pump discharge port from which fluid is discharged at a predetermined higher or lower pressure, as desired.

In the case of aircraft hydraulic systems, it is a current practice to employ hydraulic pumps which supply fluid at a prescribed pressure of say, 3,000 p.s.i. or more for use in the actuation of hydraulic cylinders. Occassionally, in such aircraft hydraulic systems it has been found desired, due to space limitations, to employ a 7 smaller hydraulic cylinder operated at a higher pressure and conversely, occasions arise when it is desired to have available, for rapid actuation of cylinders, 21 large volume of fluid at lower pressure.

Similarly, in industrial hydraulic applications, for instance, in a hydraulically operated diecasting machine or plastic injection molding machine, the molds are rapidly opened and closed by low pressure fluid and firmly held in closed position by high pressure fluid at the time that the molten material is forced into the mold cavity to form a molded article. Heretofore, the rapid traverse and high pressure closing of the molds has most advantageously been accomplished by providing for instance, a low pressure, large capacity pump for effecting the rapid opening and closing movements of the mold and a high pressure, small capacity pump for holding the molds in closed position.

With the foregoing in mind, which have been cited merely for illustrative purposes, it is a principal object of this invention to provide a simple and compact device which is operative to efliciently transform fluid under pressure delivered thereto to a diiierent higher or lower pressure.

It is another object of this invention to provide a device of the character indicated which employs annular series of differential pistons of which one set constitutes a motor and the other set constitutes a pump whereby said pistons, when reciprocated in their respective cylinders, are effective to transform low pressure fluidflow to high pressure fluid flow or vice-versa according to whether the motor actuating fluid is directed on the large set of pistons or on the small set of pistons.

It is another object of this invention to provide a device of the character indicated that has a novel valving arrangement for conducting fluid into and from the respective motor and pump chambers of the booster, debooster device.

It is yet another object of this invention to provide a pressure booster or de-booster in which the motor discharge and pump intake passages are in communication with each other.

It is still another object of this invention to provide a pressure booster or de-booster that may be employed to pressurize the intake leading to the main hydraulic pump to thus eliminate cavitation.

Another object of this invention is to provide a novel hydraulic circuit including a fluid reservoir, a pump, a selector valve, and the instant booster, de-booster device so hooked up to a work load that fluid may be selectively deiivered to the latter under pressure greater than or less than the pressure of the fluid delivered from said pump.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

Fig. l is a cross-section view longitudinally through one embodiment of the present invention, such section having been taken substantially along th line C=L-i, Fig. 2;

Fig. 2 is a transverse cross-section view taken substan tially along the lines 2-2, Fig. 1;

Fig. 3 is a transverse cross-section view taken substantially along the line 33, Fig. 1;

Fig. 4 is a fragmentary longitudinal cross-section view similar to Fig. 1 except showing a modified form of housing in which differential pistons are reciprocably mounted; and

Fig. 5 is a schematic diagram showing the booster, debooster device in use as a pump cavitation eliminator.

Referring now in detail to the drawings and first to the form of the invention illustrated in Figs.1 to 3, the same comprises a two-part hollow housing 1 including a main housing member 2 to which an end cap 3 is secured as by means of bolts 's, said main housing member 2 being formed with a port 5 which, as shown by dash lines in Fig. 1, is adapted to be communicated with a hydraulic reservoir R.

Extending centrally through said housing 1 is a cylindrical bar 6, which is nonrotatably and axially fixedly mounted in said housing as by means of the setscrew 7 in cap 3 that bears on the flattened end portion of said bar. A fluid tight seal between bar 6 and housing member 2 and end cap 3 is effected as by means of the conventional O- rings 9 and 10 or equivalent packing rings.

Rotatably mounted on said bar 6 is a cylinder assembly 11 comprising cylinder blocks 12 and 14 and an intervening sleeve 15 which are clamped coaxially together as by means of the series of bolts 16. The cylinder block 12 has a plane'annular end surface 17 and likewise, the other cylinder block 14 has a plane annular end surface 18,

. said end surfaces 17 and 18 being in sliding, sealed engagement with juxtaposed annular surfaces of the main housing member 2 and of the cap 3. The central bores 19 and 20 of said cylinder blocks 1 2 and 1,4;are smoothly finished so to make sealed engagement with the cylindrical outer surface of said bar 6 while yet the cylinder assembly 11 is capable of free rotary motion about said bar 6.

Said bar 6, between its ends and between the inner ends of cylinder blocks 12 and 14 is formed with a cam groove 21 obliquely disposed relative to the central longitudinal axis of bar 6. Rollers 23 mounted on the inner ends of radially disposed pins 24 are engaged in such cam groove 21. Said pins 24 extend diametrically through diflerential pistons 25-26 and have their outer ends slidably engaged in axial slots 22 formed in sleeve 15 whereby, upon rotation of the cylinder assembly 11 on bar 6, the cam groove 21 will cause axial reciprocation of the pistons 25-26 in the respective cylinders 27-28 in the cylinder blocks 12 and 14.

In the embodiment of the invention shown in Figs. 1 to 3 the small pistons 25 have a loose fit on the respective pins 24 and within the sockets formed in the ends of the large pistons 26 whereby said pistons 25-26 may freely slide, without binding, in their respective cylinders 27-28.

In the present case, the cylinder block 14 is formed with six equally spaced cylinder bores 28 in which the respective pistons 26 are reciprocable and each cylinder bore 28 is provided with a radially inwardly extending passage 30 that intersects the bore 20. That end of the bar 6 is formed with a threaded port and passage 31 that communicates by way of slot 32 with the cylinder passages 30 that are disposed above the horizontal centerline through bar 6. That end of said bar 6 is also formed with a slot 34 that communicates not only with the cylinder passages 30 below such horizontal center-line, but also communicates with a passage 35 through the end cap 3, which passage in turn leads to the aforementioned port 5. As is now apparent, should fluid under pressure be admitted into the passage 31, said fluid acting on those pistons 26 which have their cylinder passages 30 in communication with the slot 32 will be forced toward the left, as viewed in Fig. 1, whereupon the cylinder assembly 11 will be rotated in a counterclockwise direction as viewed in Fig. 2 to progressively and successively bring the pistons 26 into communication with such fluid under pressure.

After each piston 26 has moved as far as permitted by the cam groove 21, the continuation of the rotation of the cylinder assembly will bring the cylinder passages 30 into communication with the slot 34 whereupon the movement of said pistons 26 toward the right, as viewed in Fig. 1, will displace the fluid through the discharge passage 35 and port back to the reservoir R. Preferably, the width of the lands 36 on said bar 6 are equal to the width of the passages 30 and also preferably greater than (or at least equal to), the widths of the lands between adjacent passages 30.

The other end of said bar 6 is likewise formed with a threaded port and passage 40 that intersects slot 41, said slot 41 registering with those of the cylinder passages 42 of the respective cylinders 27 which are disposed above the horizontal center-line of bar 6. Said bar 6 is also formed with a slot 43 on the other side which communicates with those cylinder passages 42 that are disposed below such horizontal center-line, said slot 43, in turn, communicating with the passage 45 and thence by way of the annular passage 46 around the cylinder assembly 11 with the return port 5.

Thus, as the large pistons 26 are moved toward the left the fluid in the small cylinders 25 is displaced through the passages 42, slot 41, and passage 40 under increased pressure in the ratio of the areas of the respective differential pistons 26-25 less the friction which opposes the rotation of the cylinder assembly 11 on bar 6 and the reciprocation of said differential pistons. The small pistons 25 that are moved toward the right by cam groove 21 draw in fluid through passages 42, slot 43, and passages 45 and 46. Y

As heretofore described, the present device was employed as a pressure booster, that is, large pistons 26 constituted the motor and the small pistons 25 constituted the high pressure pump. As evident, when fluid under pressure is admitted into port 40, the small pistons 25 become motor pistons while the large pistons 26 become pump pistons to discharge fluid at lower pressure from port 31. In that case, the device functions as a pressure debooster.

As previously described in connection with the lands 36, the lands 47 between slots 41 and 43 are of width preferably equal to the widths of the cylinder passages 42 and at least as great as the spaces between adjacent cylinder passages 42.

In order to facilitate the selective use of this device either as a booster or as a de-booster, the ports 31 and 40 at the opposite ends of said bar 6 are connected to service ports of a four-way valve V and a pump P is connected to the inlet port of said four-way valve V. The fourth port of said valve V to which the work load is communicated to receive the desired boosted or deboosted pressure is selectively communicated with high pressure from port 40 or with low pressure from port 31. Thus, by shifting a movable valve member in valve V, the output from the pump P may be directed to either end of the bar 6, and in case said pump output is piped to the left-hand port 40, the cylinder assembly 11 will be rotated under the influence of the small pistons 25 acting as motor pistons and such motor will actuate the large size pump pistons 26 to provide an output at port 31 at less pressure but greater volume. Conversely, when the valve V is actuated to direct fluid into port 31 the pistons 26 are motor pistons whereby fluid at high pressure at port 40 is conducted through valve V to the work load.

Another use of the present device is to connect say, the theport 40 in T-fashion to the delivery line 50 of the pump P and to connect the discharge port 31 by way of conduit 51 to the intake side of the pump P. In this way, the pressure of the fluid acting on the motor pistons 25 will develop a pressure on the fluid in the pump intake line 52 thereby eliminating cavitation and, of course, the cylinder assembly 11 will rotate only when there is need for pressurizing the pump intake. The return port 5 has a conduit 53 leading to reservoir R. The pump intake line 52 is provided with a check valve 54 for building up the intake fluid pressure as aforesaid.

A signal feature of the present invention is that in view of the in-line balanced arrangement of the differential pistons 25-26 there is virtually no stress between the pin rollers 23 and the walls of groove 21 except the small amount that is required to overcome the sliding friction between the cylinder assembly 11 on bar 6 and the pistons 25-26 in their respective cylinders 27-28. I

In the embodiment of the invention shown in Fig. 4 the cylinder assembly 60 is of unitary construction and similarly, the differential pistons 61-62 are of one-piece construction. The cylinder bores 63-64 are formed from the right-hand end of the body 60 and the bores 64 are closed by cap 65 held on by screws 66, said cap and body defining the passages 30.

It can thus be seen that the booster-de-booster device herein is of simple form which is economical to manufacture and has an efficient form of low friction valving that resembles a rotary cylindrical plug valve in which the bar 6 constitutes the plug and the cylinder assembly 11 or 60 constitutes the valve body. Likewise, the cam groove 21 is formed in the bar 6 itself and does not require the usual obliquely disposed swash plate to which the pistons in known types of parallel cylinder pumps or motors are se-. cured as by means of ball swivel joints and antifriction bearings.

In both forms of the invention herein the pins 24 are preferably a snug or light press-fit in the large pistons 26 (Fig. 1) or in the large pistons 62 (Fig. 4). i

It is contemplated to form the bar 6 with apair of passages at each end that respectively communicate with slots 32 and 34 at one end and with slots 41 and 43 at the other end. In that case, port and passage 35 and also passages 45 and 46 may be dispensed with whereby said unit may be operated as a transfer pump whereby one body of fluid is employed to actuate the motor pistons (25 or 26) and another body of fluid is pumped by the pump pistons (26 or 25). The fluids may be the same except, for instance, the ,motor may be-actuated by fluid that has become heated Whereas it is desired to pump cool fluid to the work load. 7 Furthermore, when no pressure intensification or reduction is required the pistons 25 and 26 may be of the same diameter.

Another prospective use of the present invention is in sub-surface pumping operations for oil wells, water pumps, sump pumps, etc. in which the motor unit constituted by the small pistons, for example, is operated by water or oil under pressure supplied thereto and the pump unit constituted by the large pistons, for example, pumps out the well fluid including the motor discharge. Thus, port 5 will be submerged in the well fluid and the port 31 will have a pipe connected thereto leading to the top of the well.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In combination, a fluid reservoir; a pump having an intake port connected to said reservoir and a delivery port; a four-way valve having a movable valve member and provided with an inlet port connected to the delivery port of said pump, a pair of service ports one of which is alternately connected to said valve inlet port by movement of said valve member, and an outlet port adapted for connection with a fluid pressure operated device and alternately with the other of said service ports; and a fluid pressure transformer having ports connected with the respective service ports of said valve and arranged to deliver to such other service port and to said valve outlet port fluid under a pressure and rate of flow different from that which is delivered thereto from'said pump and through said one service port; said transformer having a port connected to said reservoir to accommodate flow of excess fluid or make-up fluid as the case may be, said transformercomprising a differential displacement unit of which either one of two components constitutes a fluid motor and the other component constitutes a pump driven by said motor.

2. A pressure booster or de-booster comprising a cylinder assembly provided with axially adjacent, circular arrays of coaxial cylinders of different size; means rotatably supporting said assembly; differential pistons joined together and reciprocably mounted in the respective arrays of cylinders; a housing formed with an inlet port for fluid under pressure, with a discharge port adapted to be connected with a fluid reservoir, and with a delivery port; valve means in said housing for controlling the admission of fluid from said inlet port into one array of cylinders to thereby move the pistons therein in one direction and for controlling the displacement of fluid from the other array of cylinders through such delivery port due to such movement of the pistons therein;

3. The pressure booster or -de-boostcjr of claim 2 wherein said means for rotatably supporting said cylinder assembly comprises a cylindrical bar extending therethrough and secured to said housing, said bar being formed with said inlet and delivery ports at its respective ends.

4. The pressure booster or de-booster of claim 3 wherein said bar and said cylinder assembly constitute said valve means, said bar and assembly being formed with passages that alternately communicate the cylinders of one array with saidinlet and discharge ports and that alternately communicate the cylinders of, the otherarray with said delivery and discharge ports. I

5. The pressure booster or de-booster of claim 3 wherein said cam is in the form of a peripheral groove obliquely disposed around said bar, and wherein said pistons have radially extending pins whose inner ends are engaged in said peripheral groove.

6. The pressure booster or de-booster of claim 5 wherein said assembly has axially extending slots in which the outer ends of said pins are slidably fitted to hold said pistons from turning about their axes.

7. A pressure booster or de-booster comprising a hollow housing formed with a fluid discharge port adapted for connection with a fluid reservoir; a bar extending through said housing and formed with a fluid inlet port and a fluid delivery port at its respective ends; a cylinder assembly in said housing rotatably mounted on said bar; said assembly being formed with two sets of cylinders of diflferent size arranged co w'ally around said bar and with passages successively communicating, during rotation of said asem'bly, the successive cylinders of one set with said inlet and discharge ports and the successive cylinders of the other set with said delivery and discharge ports; pistons joined together and reciprocably mounted in the cylinders of the respective sets; and cam means in said housing engaged by portions of said pistons and effective to rotate said assembly responsive to movement of one set of pistons in one direction by fluid under pressure admitted thereinto through said inlet port while fluid in the other set of cylinders is displaced through said delivery port and eflective to move said Pistons in the opposite direction during rotation of said assembly whereby fluid from said one set of cylinders is displaced into said discharge port while fluid is drawn into the other set of cylinders from said discharge port.

8. The pressure booster or de-booster of claim 7 wherein said cam means comprises a groove extending obliquely around the periphery of said bar, and wherein said pistons are provided with radially inwardly pins engaged in such cam groove.

9. A fluid motor-pump unit comprising a rotary cyl1nder block assembly formed with a circular array of motor cylinder bores and a corresponding circular array of pump cylinder bores that are coaxial and aligned with such motor cylinder bores, common pistons reciprocable in the respective bores, a bar on which said assembly is rotatably mounted, said bar being formed with cam means effective to rotate said assembly responsive to reciprocation of said pistons, said bar and assembly defining a rotary valve which successively communicates the motor cylinder bores with inlet and outlet ports formed in said bar and which successively communicates the pump cylinder bores with intake and delivery ports likewise formed in said bar, the movement of said pistons in one direction under the influence of fluid under pressure admitted into said motor cylinder bores through said inlet port being effective to discharge fluid from said pump cylinder bores through said delivery port, and such piston movement being eflective, through said cam means, to rotate said, assembly and to move said pistons in the opposite direction to discharge fluid from the motor cyl- 'inder bores through said outlet port and to draw fluid into said pump cylinder bores through said intake port. 10. A fluid motor-pump unit comprising a hollow hous' ing; a cylindrical bar extending through said housing; a cylinder block assembly in said housing and journalled 'on said bar; said assembly carrying a plurality of axial- -1y reciprocable motor-pump pistons; each piston being provided with a radially inwardly extending pin that engages in an obliquely disposed peripheral groove around said bar whereby fluid pressure actuation of said pistons in one direction rotates said assembly; said bar being formed with fluid inlet and outlet ports and with fluid intake and delivery ports communicating with the respective ends of said pistons as said assembly thus rotates and so arranged that as successive pistons are moved in one direction under the influence of fluid under pressure from said inlet port on one end, the other end displaces Reader June 3, 1941 10 2,484,884 Hanna Oct. 18, 1949 2,592,940 Monoyer Apr. 15, 1952 2,762,307 Orloff Sept. 11, 1956 2,845,030 Le Febvre et a1. July 29, 1958

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