US3433268A

US3433268A - Pressure vessel

Info

Publication number: US3433268A
Application number: US632028A
Authority: US
Inventors: Edward M Greer
Original assignee: Greer Hydraulics Inc
Current assignee: GREE HYDRAULICS OF CALIFORNIA Inc; Shared Technologies Fairchild Telecom Inc
Priority date: 1967-04-19
Filing date: 1967-04-19
Publication date: 1969-03-18
Anticipated expiration: 1986-03-18
Also published as: SE339148B; DE1750282A1; GB1222277A; DE1750282B2; FR1556755A; DK127076B

Description

March 18, 1969 E. M. GREER PRESSURE VESSEL a M, 0 m 5 f n I 8 T6 O QW 6 vm e 9 N M 6 4 3 5 W M O l 5 0 le A n F 4 no 00 5 7 w .m m5 3 o Y S 4 U-/A/f///ln- ///)HF- E B 7\ 6 0,17 ,/o o o 4,/5 3 Y 5 l uldl'l ^r /4////l-l 4 6 u a f, 5 5

Filed April 19. 1967 March 18, 1969 Filed April 19, 1967 E. M. GREER PRESSURE VESSEL FIG. 4

Sheefl 3 of 5 INVENTOR FDW/0 M 676667? ATTORNEY United States Patent Office 3,433,268 Patented Mar. 18, 1969 3,433,268 PRESSURE VESSEL Edward M. Greer, Beverly Hills, Calif., assigner to Greer Hydraulics, Inc., Los Angeles, Calif., a corporation of New York Filed Apr. 19, 1967, Ser. No. 632,028

U.S. Cl. 138-30 11 Claims Int. Cl. F161 55 00 ABSTRACT OF THE DISCLOSURE This invention relates to the art of pressure vessels, more particularly of the type known as pressure accumulators and which provide a high rate of iiow of fluid therefrom.

DESCRIPTION OF PRIOR ART As conducive to an understanding of the invention it is noted that where accumnlators are of large size requiring a relatively long bladder between the two fluids under pressure contained therein, when the bladder is compressed during operation, it is likely to rub against the side wall of the accumulator container with possibility of rupture of the bladder and failure of the accumulator. In addition, when such elongated bladder is compressed, it may form a sharp fold which is als-o likely to cause rupture of the bladder. Furthermore, as a result of flotation of the bladder, pockets of liquid, especially where highly viscous, would become entrapped between the bladder and container, thus reducing the volume of the accumulator. In addition, ybecause of the large length over diameter ratio of the bladder and tolerances in manufacturing, the valve member often will not find its seat on the port closure, but rather will be olf center, exposing the thin side walls of the bladder to the open port and thus, rupture the bladder.

Where an accumulator of the above type is used in applications which require a rapid flow from the accurnulator and turbulence is created in the outlet port, it will impede such rapid ow thereby rendering 'the accumulator inefficient for its intended function. Furthermore, where the oil port of the accumulator should close before substantially all of the oil in the accumulator is discharged, the accumulator will be inefficient in operation.

It is accordingly among the objects of the invention to provide a pressure accumulator of the type having a relatively long bladder therein, in which the unprotected side wall of the bladder will not be exposed to an open port of lower pressure than that which exists in gas pressure in the bladder and, thus rupture of the bladder is prevented.

Another object is to provide an accumulator of the above type in which the bladder is precluded from rubbing against the side wall of the container and is not likely to form sharp folds, thereby preventing rupture of the bladder with resultant failure of the accumulator and in which the formation of pockets between the bladder and container is precluded.

Another object is to provide an accumulator of the above type in which turbulence in the outlet port, even at a high rate of flow, is precluded and in which the oil port will remain open until substantially all of the oil is discharged.

Another object is to provide a valve member to be carried by the bladder of said accumulator which will not Vbe deformed when it strikes the seat defined by the oil port even with a high rate of flow from such port.

SUMMARY OF THE INVENTION According to the invention, the accumulator comprises an elongated substantially cylindro-spherical ciontainer having a central guide member secured at one end thereof and extending axially in the container. An elongated bladder positioned in the container has a mouth at one end secured to the end of the container to which the central guide member is secured, and a tapering grommet is positioned in the bladder adjacent its mouth and extends into the bladder. The bladder encompasses the `guide member and grommet, and the closed end 4of the bladder which carries a valve member, has secured thereto a second guide member yadapted to telescopically coact with the first guide member so that a sliding iit is provided therebetween.

The iirst guide member is provided with suitable apertures to permit gas under pressure to ow therethrough to charge the bladder.

The outlet port of the accumulator with which the valve member coacts is conformed as a Venturi to provide a high velocity flow therethrough that will prevent turbulence, and prevent premature closing of the valve member.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings in which are shown one or more of various possible embodiments of the several features of the invention;

FIG. l is a longitudinal sectional view of the pressure accumulator according to the invention;

FIG. 2 is a detailed longitudinal sectional view of the gas inlet end of the accumulator;

FIG. 3 is a View similar to FIG. 2 rof the oil port of the pressure accumulator, and

FIG. 4 is a view similar to FIG. 3 of another embodiment of the valve member.

Referring now to the drawings, the accumulator shown in FIG. 1 comprises an elongated container 11 illustratively substantially cylindre-spherical `and of strong rigid material capable of withstanding high pressures.

The container 11 has axially aligned

ports

12 and 13 at opposed ends thereof. Positioned in the container 11 is a partition 14 which preferably is of rubber, natural or synthetic, capable of expansion and llexure. The partition 14 is illustratively in the form of an elongated bladder which has an opening 15 at one end.

In the illustrative embodiment shown, the opening 15 has associated therewith a substantially frusto-conical grommet 16 which extends inwardly into the bladder tapering to the smaller diameter end 17 thereof. The bladder and grommet are secured to a substantially cylindrical fitting 18 which has an intermediate annular flange 19 defining an annular shoulder 21, with the portion of the flange 19 remote from shoulder 21 having an integral outwardly extending annular iin 22. The portion of the fitting 18 inwardly of the flange 19 is of reduced diameter as at 23 and designed to fit into the corresponding axial bore 24 of the grommet 16. In the preferred embodiment shown, the grommet is integral with the bladder and the mouth or opening 15 of the bladder as well as the bore surface of the grommet are bonded to the fitting as is clearly shown in the drawing. It is understood, however, that the grommet 16 could be a separate and distinct element.

The fitting 18 with the bladder and grommet bonded thereto is inserted through the port 12 of the container 11 and securely locked in place by means of a nut 25 screwed on the threaded portion of the fitting, a spacer 26 being interposed between the nut 25 and the adjacent end of the container. As a result of the tightening of the nut 25, the tting 18 will be moved outwardly until the shoulder 21 thereof abuts against the inner wall of the container adjacent the port 12 compressing the bladder material adjacent the opening 15 of the bladder to provide a dependenable seal, the abutment of the shoulder 21 against the container preventing cutting of the bladder.

The bore of the fitting 18 has an internal annular shoulder 28 against which is seated the flanged end 29 of a sleeve 31 which extends axially through the inner end of the fitting and protrudes therefrom as at 32. Secured as by force fit in said sleeve 31 is the end of an elongated hollow guide tube 35 which extends axially into the bladder. The inner end 36 of the tube extends outwardly slightly beyond the flange 29. A collar 37 positioned in the bore of the fitting 18 abuts against said end 36. The 'guide tube 35 and associated sleeve 31 are securely retained in position as by a nipple 39 screwed into the bore of the fitting 18 and abutting against the collar 317, an O-ring 41 being interposed between the collar 37 andthe end of the nipple 39 to provide a seal. A lock nut 42 securely retains the nipple in position and the outer end of the nipple is provided with a suitable air valve 43 of conventional type.

The closed end of the bladder remote from the opening 15 thereof and axially aligned therewith is of -greater thickness than the remaining portion of the bladder and defines a valve member 40. As shown in the drawing, the bladder is preferably molded with a substantially frusto-conical cup-shaped member 44 of rigid material such as sheet metal in the closed end thereof. The cupshaped member 44 has a top plate 45 secured thereto which has openings 46 to permit flow of the bladder material therein. The top plate has a central opening 47 through which extends the end 4S of a stud 49, the latter being preferably molded in said thickened portion or valve member 40 and extending axially into the bladder and being welded as at 40a to the top plate 45.

A second guide tube 51 is positioned in said bladder so that the stud 49 is telescoped in the end thereof, and the second guide tube is secured to the stud as by pinning at 52. The second guide tube 51 is of slightly greater diameter than the first guide tube 35 so that the latter may slidably fit therein as is clearly shown in the draw ings. The guide tube 35 illustratively has a plurality of openings 58 therethrough to permit flow of gas under pressure from the valve 43 into the chamber 59 defined by the bladder.

In the illustrative embodiment shown, the length of the stud 49 and the guide tube 51 are such that when the inner end 55 of the guide tube 35 abuts against the inner end 56 of the stud 49, the end 57 of the guide tube 51 will be slightly spaced from the inner end 32 of sleeve 31 and all of the openings 58 will be closed by tube 51.

The port 13 which is of diameter sufliciently great to permit the bladder and fitting 18 to be inserted therethrough, has mounted therein an outlet closure assembly 61. Preferably, this assembly is of the general construction shown in U.S. Reissue Patent No. 23,343, by the use of which the closure assembly `61 may not be removed so long as there is any substantial pressure in the container.

As shown in the drawings, the assembly 61 desirably comprises a housing 62, preferably a tubular member which desirably has an external annular flange `60 defining a shoulder 63 at the inner end thereof of outer diameter less than that of port 13. A locking member 64, illustratively a ring of greater outer diameter than said port 13 and deformable to permit its insertion thereinto, encompasses said tubular member and is seated on the rim 65 of port 13, the inner diameter of said ring 64 being less than the outer diameter of shoulder 63 so that said shoulder may seat on said ring. Secured to the top surface of said deformable ring 64 is a resilient ring 66 which encompasses the flange 60 as shown, with the outer periphery of said 4ring 66 adapted to seat against the curved inner surface of the container adjacent port 13. Encompassing the tubular member 62 and in juxtaposition with said port 13 is a rubber gasket or O-ring 67 which serves effectively to prevent leakage between the wall of port 13 and the outer wall of tubular member 62 when a nut 78 is screwed on the externally threaded portion 71 of the tubular member and moves a sleeve 72 against the gasket `67 to compress the latter with respect to the deformable ring 64.

As shown in FIG. 3, the bore 70 of the tubular member 62 which defines the oil passageway, is of reduced diameter as at 75 adjacent the inner portion 76 thereof, such portion 76 being beveled as shown and defining a seat for valve member 40 carried by the bladder. In addition, the bore portion 79 of the tubular member outwardly of the reduced diameter portion 75 is also beveled, although at a lesser angle than that of the beveled portion 76.

'Ihe configuration of the bore 70 of tubular member 62 thus forms a Venturi so that ywhen fluid flows through said bore, the pressure on each side of the reduced diameter portion and the velocity of flow at such reduced diameter portion will be greater than through the adjacent portions.

In the operation of the accumulator the bladder 14 may first be charged with gas under pressure through the valve 43. The ygas will flow through the guide tube 35 and through the penforations 58 therein into the bladder 14 to charge the latter. As the result of ysuch charge, the bladder will expand and elongate until the valve member 40 thereof seats on the beveled portion 76 of bore 70 of ltubular member 62 to close the latter. Thereupon, the gas valve 43 is closed.

A fluid such as oil under pressure greater than that of the gas in bladder 14 is lforced through bore 70 of tubular member 62 into the container.

As a result, the valve member 43 will fbe moved inwardly off its seat and such valve member will be retained in axial alignment with the seat 76 'by reason o-f the sliding fit of the guide tube 51 on the guide tube 35, the guide tube 51 moving away from the bore 70 of the tubular member 62, its movement being limited by the abutment of the end y'55 of the tube 35 against the end 56 of stud 49.

As the result of the flow of the `fluid into the container, the bladder will be deformed and the gas therein further compressed. By reason of the fact that the telescoped

tubes

35 and 51, which extend through the bladder 1'4, form a substantially rigid member, even though the bladder is compressed it will be retained in the center of the container 11 so that it will not rub against the wall thereof with resultant wear and possibility of rupture and will not form sharp folds which are also likely to cause rupture of the bladder.

Furthermore, it is to be noted that the tube `51 encompasses the tube 35 and hence before the side Wall of the compressed bladder 14 can move against the end 57 of the outer tube 51 which might cause cutting of the bladder, such end 57 will have been moved in close proximity to the grommet 16 as at 80. As the end of the bladder adjacent its mouth will fold inwardly against the grommet there will be a reduced angle of fold as at 80 that will prevent tearing of the mouth of t-he bladder from its `retaining means and furthermore, since all of the openings 58 will lbe closed 'by the tube 51, there will be no danger of extrusion of said bladder therethrough.

When the bladder is compressed, `gas under pressure will be entrapped in the region 80 (FIG. 2) maintaining the reduced angle of fold. Furthermore, gas under pressure will also be entrapped at the region 80' adjacent the lower end of the grommet 16 to prevent the bladder wall from moving against the end 57 of tube 51 thereby protecting the bladder against cutting.

When a valve (not shown) controlling the outlet port defined by the bore 70 of member 62 is opened, the compressed gas inthe bladder 14 will cause the latter to expand forcing the oil through the bore 70.

Due to the reduced diameter portion 75 of bore 70, the pressure in the upper portion 76 of such bore will be greater than the pressure at the reduced diameter portion 75 thereof and hence premature closing of the valve, due to sucking action, will be precluded, for maximum expulsion of oil from the container 'with resultant high efficiency. Furthermore, the Venturi action provided by such reduced diameter portion will cause the velocity of the flow to be increased and by reason of such high velocity, turbulence in the bore with resultant cross currents will be minimized. As a result, a high rate of flow will be provided fromI the outlet bore 70.

When the valve member 40 does finally move against its seat 76, even though it may strike the seat with great impact, due to the fact that the cup-shaped rigid member 44 has a transverse reinforcing top wall 45, the member 44 will not be deformed which could cause it to extrude through bore 70 with resultant failure of the device.

The embodiment shown in FIG. 4 is similar to that shown in FIGS. 1 to 3 and corresponding elements have the same reference numerals primed.

The embodiment of FIG. 4 differs substantially solely in the construction of the valve member 40.

Thus, the valve member 40' comprises a substantially fFusto-conical tbody portion 81, preferably of stainless steel, having a tapered side wall 82 and a top wall 83 having passageways 84 therethrough leading into a central cavity 85 in the undersurface of body portion 81.

The top wall A83 has an axial stem 86 which is secured to the lower end of a guide tube 51' as by pinning at 52.

The blader 14 is initialy molded with the body portion 81 in the closed end thereof and `with the bladder material flowing through passageways 84 and filling the central cavity 85.

Thus, when the valve member 40 is moved against the seat 76', the tapered side wall 82 will rest on the seat 76 and due to the inherent rigidity of the valve member it will -not extrude through bore 70' even if it hits seat 76 with high impact.

In the embodiment of FIGS. 1 to 3, the body portion of the valve member is completely embedded in the material of the bladder. This arrangement is desirable when liquids are used that are corrosive to ordinary steel. In the embodiment of FIG. 4, the body portion 81 is preferably of stainless steel which is highly resistant to corroslon.

With the construction above described, an accumulator is provided which may be of large size and which will insure that the bladder therein will not rub against the wall of the container with resultant rupture thereof and failure of the accumulator and without formation of sharp folds which may also cause rupture of the bladder. Furthermore, a large rate of flow at high velocity will be provided from such accumulator so that it may perform its intended functions.

As many changes could be ,made in the above constructions, and many apparently widely different embodiments of this invention could be made, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A pressure vessel comprising an elongated container, an elongated deformable bladder in said container of volume substantially conforming to that of said container when the bladder is expanded, said bladder having a mouth at one end and a valve member at its other end axially aligned with said mouth, said container having axially aligned ports defining a gas and oil port respectively, means securely clamping said bladder mouth with respect to said container adjacent said gas port, a guide tube extending axially into said bladder a portion of the length thereof and rigidly secured at one end with respect to said gas port, means to provide flow of gas through said guide tube into the bladder, a substantially rustoconical grommet encompassing said tube adjacent its secured end and in juxtaposition to the bladder adjacent its mouth, said grommet extending into said bladder with the larger diameter end of the grommet adjacent the mouth of the bladder, the configuration of said grommet reducing the angle of fold of the bladder adjacent its mouth and entrapping air at such region upon compression of the bladder thereby preventing tearing of the mouth of the bladder from its clamping means, a second guide tube rigidly secured at one end with respect to the valve member end of the bladder and extending axially into said bladder, said second tube having a sliding fit with respect to said first tube, a tubular member rigidly secured in the oil port of said container, said tubular member having a bore therethrough, defining a seat for said valve member at its inner end, said bore being conformed to provide a Venturi action there through.

2. The combination set forth in claim 1 in which said bore is of reduced diameter between its ends with the wall surface of said bore tapering outwardly from said reduced diameter portion to form said Venturi, the inner tapered portion of said bore defining said valve seat.

3. The combination set forth in claim 1 in which the means to provide ow of gas through said first guide tube into the bladder comprises a plurality of longitudinally spaced openings through said first guide tube, the end of said second tube being movable into close proximity to the inner end of said grommet when the bladder is compressed, all of said openings through said first guide tube being closed by said second guide tube when the bladder is compressed.

4. The combination set forth in claim 1 in which said second tube encompasses said first tube and the end of said second tube is movable into close proximity to the inner end of said grommet when the bladder is compressed.

5. The combination set forth in claim 1 in which an elongated stud is secured at one end in the valve member carried by said bladder and extends axially into said bladder, said second tube encompassing said stud at one end and being secured thereto, said second tube encompassing said first tube, the inner ends of said first tube and said stud abutting to limit the inward movement of said valve member.

6. The combination set forth in claim 5 in which the end of said second tube is movable into close proximity to the inner end of said grommet when the bladder is compressed.

7. The combination set forth in claim 1 in which said valve member comprises a substantially frusto-conical body portion having a top wall rigid therewith, said valve member being integral with the closed end of the bladder axially thereof, said second guide tube being rigidly secured with respect to the top wall of said body portion.

8. The combination set forth in claim 7 in which said valve member has an axial opening in said top wall and an elongated stud extends through said opening and is rigidly connected at one end to said top wall, said stud extending axially into said bladder, said second tube encompassing said stud `at one end and being secured thereto.

9. The combination set forth in claim 1 in which said grommet and said bladder are integrally formed, said grommet having an axial bore therethrough leading into the mouth lof said bladder, a hollow fitting positioned in the bore of said grommet and extending outwardly beyond the mouth of said bladder, said grommet and said bladder mouth being secured to said fitting, said fitting extending through the gas port of said container and being rigidly secured therein, the end of said first guide tube being secured in the inner end of said tting and an air valve secured in the outer end of said tting.

10. The combination set forth in claim 9 including an O-ring provided between the outer end of said rst tube and said air valve.

11. The combination set forth in claim 9 in which the bore of said fitting has an internal annular shoulder, a sleeve having an external flange positioned in said bore and seated on said shoulder, the outer end of said rst guide tube being rigidly secured in said sleeve, a nipple positioned in the outer end of said fitting, `an O-ring positioned between the inner end of said nipple and the outer end of said rst tube and said air valve being positioned in the outer end of said nipple.

References Cited UNITED STATES PATENTS ROBERT R. MACKEY, Primary Examiner.