US2786424A

US2786424A - Fluid pump

Info

Publication number: US2786424A
Application number: US495372A
Authority: US
Inventors: Thomas E Raymond
Original assignee: SIMPLEX ENGINEERING Co
Current assignee: SIMPLEX ENGINEERING Co
Priority date: 1955-03-21
Filing date: 1955-03-21
Publication date: 1957-03-26
Anticipated expiration: 1974-03-26

Description

T. E. RAYMOND FLUID PUMP March 26, 1957 2 Sheets-Sheet 1 Filed March 21 1955 INVENTOR. 7710/7705 5 Pay/wand AUOP/VEYS March 26, 1957 T. E. RAYMOND 2,

FLUID PUMP Filed March 21, 1955 2 Sheets-Sheet 2 h. 82 will I ////////W////fl////////////////% I N V EN TOR. Thomas E Pay/770x70.

A TTORNEYS United States Patent FLUID PUMP Thomas E. Raymond, Zanesville, Ohio, assignor, by direct and mesne assignments, of ninety percent to Simplex Engineering Company, Zanesville, Ohio, a corporation of Ohio, five percent to Palmer Fultz, and five percent to Warren H. F. Schmieding, Columbus, Ohio Application March 21, 1955, Serial No. 495,372

6 Claims. (Cl. 103-174) This invention relates generally to apparatus for pumping fluids and particularly to a novel structural arrangement for such apparatus which prevents any leakage of fluid, from high pressure zones in the apparatus, from passing to the exterior of the pump structure.

In general, the apparatus of the present invention comprises means forming a cylinder block, including cylinder means with piston means arranged for reciprocating movement therein. The cylinder block is provided with a casing or cover adapted to close and seal an end of such cylinder means, whereby the casing forms a portion of the wall means of a chamber subjected to relatively high fluid pressure. Upon reciprocation of the piston means, fluid is drawn into the cylinder means, subjected to relatively high pressures, and thence discharged therefrom. To prevent any fluid which leaks between the junction of the cylinder block and easing from passing to the exterior of the apparatus, the present invention includes passage means located along such junction and the fluid leakage along such junction is caused to enter such passage means instead of continuing along the junction to the exterior of the apparatus. According to the present invention, the passage means intercepting the fluid leakage is connected with the intake manifold of the pumping apparatus which provides means for receiving any fluid which may leak along the junction and which provides a zone of relatively low pressure towards which such fluid leakage will be caused to progress.

It is therefore an object of the present invention to provide a pumping apparatus wherein fluids can be subjected to relatively high pressures Without the occurrence of leakage of fluid from the apparatus.

It is another object of the present invention to provide an apparatus for pumping fluids at relatively high pressure without the occurrence of leakage of the liquid from the apparatus with such apparatus being nevertheless formed of simple and inexpensive structural components which can be readily fabricated and assembled by mass production techniques.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Figure l is a side sectional view of the pumping apparatus constructed according to the present invention. The section is taken substantially along the line 1--1 of Figure 2;

Figure 2 is an end sectional view of the pumping apparatus of Figure 1, with the section being taken along the line 22 of Figure 1;

Figure 3 is a partial top sectional view of the apparatus of the preceding two figures, with the section being taken substantially along the line 3-3 of Figure 2;

Figure 4 is a broken perspective View, partially in section, showing a portion of the structure of the pumping apparatus of the preceding figures, with such structural ice portion being constructed according to the present inven-' tion. The section is taken substantially along the line 44 of Figure 3.

Referring more in detail to the drawings, a fluid translating apparatus constructed according to the present in= vention is illustrated in Figures 1 and 2. Such apparatus includes a casing indicated generally at 20. Casing 20 includes a cylindrical casing portion 22 which is closed at one end by an end plate 23 and at the other end by an end plate 24. The casing portion 22 surrounds a piston block, indicated generally at 26, which piston block is formed with a plurality of radially extending passages which form a plurality of cylinders such as are indicated at 29 and 30. The inner end of each of the cylinders opens on a common chamber 32. A plurality of pistons are journaled in the cylinders with two of such pistons being indicated generally at 34 and 35 in Figure 2.

To provide driving means for the pistons, a shaft 36 is rotatably carried by the

end plates

23 and 24 of the housing by bearings 37 and 38. Shaft 36 is provided with an eccentric portion 40 which includes an outer cylindrical shell 41 rotatably carried on the eccentric portion by bearings 42. The eccentric shell 41 includes an outer surface 44 which is engageable with inner end surfaces 46 of the pistons so as to impart radially outward movement to the pistons upon rotation of the shaft 36.

Each of the pistons 34 is provided with a longitudinally extending cavity 50 drilled inwardly into the outer piston end, and a spring 52 is carried in each piston cavity, in compressed configuration between an inner surface 54 of the casing portion 22 and a bottom surface 55 of the piston cavity 50. Hence it is seen that springs 52 serve to constantly urge movement of the pistons radially inwardly against the outer surface of the eccentric.

Referring again to Figure 1, the end plate 23 includes an intake opening 60 which connects with an annular intake manifold 62. A plurality of passages 63 are formed in the cylinder block 26 and connected with the annular intake manifold 62. Each of such passages 63 is provided with an intake valve mechanism which includes a ball 65, a seat 66 and a spring 67.

The end plate 24 is provided with a discharge passage 70 which communicates with an annular discharge manifold 72. A plurality of passages 74 are formed in the cylinder block 26 and connected with the annular discharge manifold 72. A discharge valve mechanism is provided in each of the passages 74 with each of such valve mechanisms including a ball 76, a seat 77, and a spring 78.

It should be noted that the intake and discharge valve mechanisms of each cylinder is retained and seated in axially aligned holes of different diameters to provide a simple and inexpensive valve structure which can be readily assembled in production. The axially aligned holes form a chamber intermediate the intake valve ball 65 and exhaust valve ball 76 which chamber is connected to a passage 82 leading to the upper portion of the cylinder 30.

In operation of the valve mechanisms, when piston 35 moves inwardly, intake valve ball 65 opens and fluid is drawn inwardly from the annular manifold 62, through the

passage

63, 80 and 82 and thence into the cylinder 30. When the piston 35 moves outwardly, intake valve ball 65 closes and the pressure exerted by the fluid opens the discharge valve ball 76 whereby fluid is forced outwardly through the

passages

82 and 80, past the exhaust valve ball 76, and thence through the annular exhaust manifold 72 and out through the opening 70.

Reference is next made to Figure 4 which consists of a perspective view clearly illustrating a structural arrangement for preventing fluid subjected to high pressures in the cylinder from leaking to the exterior of the casing. The

cylinder block 26 is illustrated with a portion of the cylindrical casing portion 22 removed to expose the top of the cylinder 29 and other adjacent interior structure. Cylinder block 26 includes an .outer peripheral surface 90 which conforms in shape with the inner cylindrical surface 54 of the casing portion 22. The surface 91? is provided with two circumferentially extending

grooves

92 and 93.

Grooves

92 and 93 are located on each side of the end of the cylinder 29 and are thereby interposed in the path of any fluid which may leak between the surfaces 54 and 9%. Any such fluid leaking between these surfaces will enter the

grooves

92 and 93, and from such grooves the fluid will enter radially extending

passages

95 and 96, each of which communicates with a passage 1% formed by a hole drilled through the cylinder block 26. Passage 104) communicates with an inwardly extending passage 103 formed at the junction of the end plate 23 and the cylinder block 26. The passage 103 in turn communicates with the annular intake manifold 62. According to the preceding description, it will be understood that any fluid which may leak between the confronting surfaces 54 and 90 of the casing portion 22 and the cylinder block 26 will be caused to progress towards the zone of relatively low pressure provided by the intake manifold of the apparatus. Hence, all fluid leakage is intercepted prior to its passage to the junction of surfaces which lead to the exterior of the apparatus. At this point it should be noted that suitable resilient seals, such as O-rings 169, are provided between the confronting

surfaces

106 and 107 to furnish a positive seal between the interior of the apparatus and the environment. Hence all fluid which passes between the

surfaces

54 and 93 will be efllciently urged towards the annular intake manifold 62 rather than passing between the junction of the surfaces Hi6 and 107. It will be understood that should a leakage condition occur at the resilient seal 109, the fluid will not pass to the exterior of the apparatus since the fluid will move more readily towards the low pressure zone provided by the intake manifold than towards the relatively higher atmospheric pressure towards which such liquid would have to move were it to pass between the confronting

surfaces

106 and 107. I

In order to render the structure just described as effec tive as possible, it is desirable to keep the leakage of fluid between the surfaces 54 and 90 to a minimum by providing intimate sealing contact between such surfaces. It will be understood, of course, it is impossible with inexpensive and rapid mass production techniques, to consistently provide a complete seal merely by surface finish and tolerance control. In order to achieve the desired result of keeping leakage to a minimum, the inner diameter of the casing portion 22 is formed of slightly lesser diameter than the outer diameter of the cylinder block 26. Casing portion 22 is then either shrunk or pressed into position in surrounding relationship with the cylinder block 26 whereby the inner surface 54 of the cylindrical shell 22 is caused to intimately contact the outer surface 90 of the cylinder block 26. With this arrangement, leakage between the confronting surfaces of the casing portion and cylinder block is kept to a minimum without the need of expensive fitting and surface finishing operations. As an ultimate result, the passage means for returning any leakage to the intake manifold, can completely and efficiently return all fluid leakage to the low pressure zone furnished by the intake manifold. In operation, the apparatus of the present invention is adapted to hydraulically vary the length of stroke negotiated by the piston means 34 by varying the pressure in the crankcase chamber 32. Since the stroke of the piston is variable responsive to variations in liquid pressure in the crankcase chamber 32, the present apparatus is readily adaptable to constantly maintain predetermined flow characteristics for the fluid being discharged to a load, and such flow characteristics can be maintained substantially constant independently of the speed of rotation at "which the pumping apparatus is driven.

A detailed description of similar method and apparatus for hydraulically varying piston stroke is set forth in considerable detail in co-pending application Serial Number 450,468, filed August 17, 1954.

To briefly describe the operate, however, the shaft 36 of the apparatus is driven by a prime mover which causes radially outward movement of pistons in the cylinders. The pistons are moved radially inwardly under the compression forces exerted by the springs. The inward stroke of each piston serves to draw fluid into the cylinder chamber, and after fluid is drawn into the cylinder on the inward stroke of the piston, such piston is then driven radially outwardly by the eccentric 49. Fluid is thereby forced against the ball of the discharge valve which valve is opened to permit the discharge of fluid to the annular discharge manifold. The fluid then passes outwardly through the passage 70 to the load being driven by the apparatus.

In negotiating an inward stroke, the inner end of each piston is exposed to the crankcase chamber 32 and subjected to the pressure of the fluid in such chamber. It will be understood that if the pressure in chamber 32 is sufliciently low, as compared to the combined effects of the compression force of the piston return spring 52 and the fluid pressure in the cylinder, the piston will negotiate a relatively long stroke with the maximum stroke length occurring when the inner end of the piston continuously contacts the outer surface of the eccentric 40.

If the fluid pressure in chamber 32 is in any manner increased beyond the stroke condition set forth above, a fluid pressure value will be reached at which the combined eifect of spring 52 and the cylinder pressure is insufiicient to completely return the piston to its inner limit of travel. When such fluid pressure value occurs, the piston will no longer continuously contact eccentric 40 throughout the cycle, and the inner limit of piston travel will be hydraulically established by fluid pressure in chamber 32 as compared to being mechanically established by the eccentric surface as was the case when the low pressure condition existed in chamber 32.

As the pressure in chamber 32 is progressively in creased in magnitude, relative to the combined effect of the return spring 52 and the fluid pressure in the cylinder, the stroke of the piston will be progressively shortened, and an operating condition will ultimately be reached wherein the bottom surface of the piston is mechanically engaged only by the offset portion of the eccentric. At such ultimate operating condition fluid pressure in chamber 32 will exert a limiting effect on the length of the stroke of the piston.

To hydraulically vary the pressure in the crankcase chamber .32, a radially extending passage 129 extends inwardly through the end plate 24 and communicates with an annular passage 122 which surrounds the shaft 36. Annular passage 122 in turn connects with the inner chamber 32. Since fluid can pass around the rollers of bearing 38, through a passage 124, and past the eccentric shell 41, it will be understood that variations in fluid pressure at passage 12%? will produce variations in the fluid pressure in chamber 32. Hence, it is seen that variations in the pressure exerted on the lower portions of the pistons will result from pressure variations at passage 120. With this arrangement, appropriate external control apparatus, including appropriate detection apparatus for detecting various desired load conditions, can be connected in pressure responsive relationship with the passage 120. By use of such control apparatus, the stroke length of the piston means and hence the volumetric discharge cycle of the apparatus can be readily varied to effect various controlled operations.

To adapt the present apparatus for an alternate control arrangement, the structure is arranged to readily connect the crankcase 32 with the intake passage 60 by a chamber 128 and a passage 13th. When a plug 132 is removed from the end of passage 130, fluid is free to pass from crankcase 32, past the roller of bearing 37, and through chamber 128 and passage 130 to the intake passage 60.

In summary, it will be understood that the present invention provides novel apparatus adapted to efliciently pump fluid at relatively high pressure, and which comprises novel structure adapted to completely prevent the leakage of high pressure fluid to the exterior of the apparatus. Moreover, the pump of the present invention is formed from relatively few component parts which can be inexpensively fabricated and assembled by mass production techniques.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1. A fluid energy translating apparatus comprising, in combination, a block member with cylinder means formed therein, said cylinder means including an inlet port and an outlet port; piston means arranged for reciprocation in said cylinder means; a closure member for said cylinder means engaging said block member at a junction; a passage means formed by recessing at least one of said members, said passage means extending along the entire length of said junction; means forming a chamber communicating with one of said ports; and a second passage means formed in one of said members and connecting said first mentioned passage means with said chamber whereby fluid passing along said junction enters said passage means and progresses towards said chamber.

2. A fluid energy translating apparatus comprising, in combination, a block member with cylinder means formed therein; an intake chamber for conducting fluid to said cylinder means; piston means arranged for reciprocation in said cylinder means; a closure member for said cylinder means engaging said block member at a junction; a passage means formed by recessing at least one of said members at said junction, said passage means extending along the entire length of said junction; and a second passage means formed in one of said members and connecting said first mentioned passage means with said intake chamber.

3. A fluid energy translating apparatus comprising, in combination, block means with cylinder means formed therein, said cylinder means including an inlet port and an outlet port; piston means arranged for reciprocation in said cylinder means; an annular casing portion having an inner cylindrical surface engaging an outer cylindrical surface on said block means at a junction of surfaces, said annular casing forming a cover for an end of said cylinder means; a closure means for an end of said junction of surfaces; passage means disposed along said junction of surfaces intermediate said end of the cylinder means and said closure means; means forming a chamber communicating with one of said ports; and means connecting said passage means with said chamber whereby fluid passing along said junction of surfaces enters said passage means and progresses towards said chamber.

4. A fluid energy translating apparatus comprising, in combination, block means with a cylinder formed therein; a piston moveably disposed in said cylinder and exposed to pressurized fluid therein; closure means for said cylinder, said closure means engaging said block means at a junction forming a minute passage; and means forming an inlet chamber supplying fluid to said cylinder, said inlet chamber being connected to said minute passage for receiving any fluid that escapes from said cylinder along said junction.

5. A fluid energy translating apparatus comprising, in combination, block means with a cylinder formed therein; a piston moveably disposed in said cylinder and exposed to pressurized fluid therein; closure means for said cylinder, said closure means including a surface engaging a confronting surface on said block means, said eonfronting surfaces forming a minute path for the passage of fluid from said cylinder; means forming an inlet chamber for supplying fluid to said cylinder; and passage means connecting said minute path to said inlet chamber to deliver fluid leaking between said surfaces to said inlet chamber.

6. A fluid energy translating apparatus comprising, in combination, block means with a cylinder formed therein, said cylinder including an inlet port and an outlet port; a piston moveably disposed in said cylinder and exposed to pressurized fluid therein; closure means for said cylinder, said closure means engaging said block means at a junction forming a minute passage; and means forming a chamber communicating with one of said ports, said chamber being connected to said minute passage for reeeiving any fluid that escapes from said cylinder along said junction.

No references cited.