GB2109463A

GB2109463A - Pressure vessel assemblies

Info

Publication number: GB2109463A
Application number: GB08225660A
Authority: GB
Inventors: Abduz Zahid
Original assignee: VSI Corp
Current assignee: Shared Technologies Fairchild Telecom Inc
Priority date: 1981-09-08
Filing date: 1982-09-08
Publication date: 1983-06-02
Also published as: IT8223172A0; FR2512508A1; IT1152816B; GB2109463B; SE8204149L; DE3229923A1; SE8204149D0; JPS5842801A

Abstract

A pressure accumulator has an assembly 13 adapted to be mounted in the oil port of the pressure vessel of the accumulator. The oil port assembly 13 is inserted into the interior of the pressure vessel through an enlarged gas charging port. The oil port fitting 16 has an annular flange portion 19 sized to engage against the interior wall portion 14 of the vessel 10 surrounding the oil port to provide a metal to metal contact. Surrounding the flange portion 19 and spaced from the oil port 15, there is a radially extending ledge portion 20. An elastomeric gasket member 35 is bonded to the flange 19 and ledge 20. The gasket has a downwardly directed depending bead portion projecting below the ledge portion 20. When the oil port assembly is clamped in position in the oil port by tightening a nut 38, the bead portion is compressed against the vessel and a tight leakproof connection between the oil port assembly and the pressure vessel 10 is effected. <IMAGE>

Description

SPECIFICATION Pressure vessel assemblies The present invention relates to pressure vessel assemblies which may be used as hydraulic pressure accumulators such as are frequently employed for energy storags or as damping devices in hydraulic installations.

Such devices typically comprise a pressure vessel having an oil port in one end and a gas charging port in the other end. The pressure vessel is divided into two chambers by a distensible bladder member, one such chamber being connected to the oil port and the other to the gas charging port. Typically, there is mounted in the oil port an oil port assembly including a valve which is shut when the pressure within the gas chamber is greater than the pressure in the oil line and which opens when the pressure conditions are reversed.

Heretofore, the means or mechanism whereby the oil port assembly is supported within the pressure vessel has involved the use of complex and expensive fixtures which ensure against leakage and yet none the less afford a dependable connection between the oil port assembly and the hydraulic line connected to such assembly. More particularly, the expedients employed in retaining the oil port assembly in position have included split metal rings, compression washers and O-rings.

Such devices in addition to adding substantially to the cost of construction, have greatly increased the complexity of manufacturing operations necessary for assembling the device. Additionally, the positioning of the various O-rings within the relatively limited clearance areas provided therefore is a delicate task and it is possible in inserting the O-rings to scuff or abrade the surfaces thereof, whereby sources of leakage are developed under the high pressures encountered in the operation of the system.

According to the present invention there is provided a pressure vessel assembly comprising a generally cylindrical pressure vessel having a gas charging port at one end and an oil port at the other end, the diameter of said gas port being greater than the diameter of said oil port, a bladder assernbly mounted in the vessel and dividing the interior thereof into two chambers communicating respectively with the gas port and the oil port, a gas charging valve assembly mounted in the gas port, an oil port assembly mounted in the oil port, the oil port assembly including a fitting having a cylindrical sleeve portion with an external threaded portion and a flange at the upper end portion thereof, the diameter of the flange being greater than that of the oil port and smaller than that of the gas port, the undersurface of the flange engaging interior wall portions of the vessel at an annular contact area surrounding the oil port, an elastomeric gasket bonded to the flange and extending radially therebeyond, the gasket, in the unstressed condition thereof, including a depending annular bead portion extending to a level below other portions of the undersurface of said gasket and below the level of said undersurface of said flange, and a clamp nut threadedly mounted on the threaded portion of the sleeve portion, externally of the vessel and reacting against the vessel to thereby tightly urge the undersurface of the flange against the said contact area, and to compress the bead portion against internal wall portions of the vessel radially outwardly of the contact area.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which; Fig. 1 is a side elevational view of a hydraulic accumulator in accordance with the invention; Fig. 2 is a magnified view in section illustrating the oil port assembly prior to insertion in the oil port; and Fig. 3 is a fragmentary section taken on the line 3-3ofFig. 1.

Turning now to the drawings, there is shown in Figure 1 an accumulator device which includes a generally cylindrical pressure vessel 10 having a gas charging valve assembly 11 at the upper end 1 2 thereof, and having an oil port assembly 1 3 mounted in the lower end 14 thereof.

The oil port assembly 13 is mounted in oil port 1 5 formed in the lower end 14 of the vessel 10.

The oil port assembly includes an elongate depending sleeve 1 6 externally threaded as at 17.

The upper end 18 of the oil port assembly includes a radially projecting flange 1 9 sized to engage against the metal portions of the vessel immediately surrounding the oil port 1 5. The flange includes a further radially extending annular ledge portion 20.

A poppet valve member 21 is provided including a heat portion 22 and an elongate stem 23. The undersurface of the head 22 is beveled as at 24, the said beveled portion being inclined to mate with complemeritally beveled portion 25 of the oil port assembly, the said portion 25 forming a seat for the portion 24 of the poppet valve head 22.

The stem 23 of the valve head 22 is guided for vertical movement within aperture 26 formed at the junction of radially inwardly extending spaced rib members 27, said aperture being of larger diameter at its lower portion 26'.

The end portion 28 of the valve stem 23 is threaded as at 29. A collar portion 30 having an upwardly directed internal shoulder 31 is seated over the end of the stem, the upwardly directed shoulder 31 butting against depending shoulder portion 32 formed on the stem. A lock nut 33 is biased against the collar 30 retaining the same in position on the stem. A lift spring member 34 is sleeved over the stem 23, the upper end of the spring being biased against the under surface of the head 22 of the valve member and the lower end of the spring reacting against the ribs 27. In this manner, the valve 21 is retained in a normally raised position.

Referring more particularly to Figure 2 there is bonded to the flange portion 1 9 of the oil port assembly and to the radially projecting ledge 20 thereof, an annular elastomeric gasket member 35. The undersurface 36 of the gasket member 35 is inclined to mate with or follow the slope or inclination of the internal wall portions of the vessel surrounding the oil port 1 5. The gasket member 35 in the unstressed condition thereof depicted in Figure 2, includes an annular continuous depending bead 37. The bead 37 is located, at least partly, beneath the ledge portion 20 of the oil port assembly.

To assemble the oil port assembly 13, the spring member 34 is sleeved on stem 23, the end 28 of the latter then being inserted through aperture 26 in ribs 27. The collar 30 is then positioned over the end 28 of stem 23 and nut 30 is screwed on the threaded position 29 of end 28.

The oil port assembly 1 3 is then positioned within the vessel by introducing the same through the gas charging port, the diameter D of which is larger than the widest diameter of the metal portion 20 of the oil port assembly 13. If necessary the elastomeric gasket member 35 may be deflected inwardly in order to permit passage of the oil port assembly through the gas charging port.

After the sleeve 1 6 of the oil port assembly has been passed through the oil port 1 5 from the interior of the pressure vessel 10, clamp nut 38 is mounted over threaded portion 1 7 and tightened to bring the downwardly facing shoulder 1 9 of the oil port assembly into metal to metal contact with the interior wall portions of the vessel surrounding oil port 15. As will be appreciated from a comparison of Figures 2 and 3, tightening of the clamp nut 38 has caused the depending bead portion 37 to be deflected upwardly to define a high compression annular contact area between the gasket and interior surface wall portions of the pressure vessel.Since the bead portion 37, is at least partially covered by the ledge portion 20 of the oil port assembly, the rubber of the gasket is essentially extruded inwardly and constrained to define a tight seal area preventing leakage of fluid through the area between the oil port and the oil port assembly.

The operation of the device will be readily understood and is essentially conventional. A bladder member B is mounted within the pressure vessel, the rim or margins of the bladder being in sealed engagement with interior wall portions of the vessel. The bladder B in substance divides the interior of the vessel into two chambers and, more particularly, an upper chamber in communication with the gas charging valve assembly 11 and lower chamber in communication with the oil port via the oil port assembly 1 3.

When the pressure in the gas chamber exceeds the pressure in the hydraulic line which communicates with bore 40 within the sleeve 1 6, the bladder B will press downwardly against head 22 of the valve member 21 causing the valve to seat against valve seat portion 25.

When the pressure within the hydraulic line exceeds the pressure within the gas chamber, the valve head 22 will be unseated from the beveled surface 25 and hydraulic fluid will then be free to pass upwardly through bore 40 through the spaces between the ribs 27 and into the interior of the pressure vessel. The fluid entering into the pressure vessel compresses the gas captured between the bladder member and the gas charging valve assembly. In such mode, energy is stored in the compressed gas which energy is released to the hydraulic system when the pressure within the hydraulic system falls to a level below the pressure in the gas chamber of the device.

Claims

1. A pressure vessel assembly comprising a generally cylindrical pressure vessel having a gas charging port at one end and an oil port at the other end, the diameter of said gas port being greater than the diameter of said oil port, a bladder assembly mounted in the vessel and dividing the interior thereof into two chambers communicating respectively with the gas port and the oil port, a gas charging valve assembly mounted in the gas port, an oil port assembly mounted in the oil port, the oil port assembly including a fitting having a cylindrical sleeve portion with an external threaded portion and a flange at the upper end portion thereof, the diameter of the flange being greater than that of the oil port and smaller than that of the gas port, the undersurface of the flange engaging interior wall portions of the vessel at an annular contact area surrounding the oil port, an elastomeric gasket bonded to the flange and extending radially therebeyond, the gasket, in the unstressed condition thereof, including a depending annular bead portion extending to a level below other portions of the undersurface of said gasket and below the level of said undersurface of said flange, and a clamp nut threadedly mounted on the threaded portion of the sleeve portion, externally of the vessel and reacting against the vessel to thereby tightly urge the undersurface of the flange against the said contact area, and to compress the bead portion against the internal wall portions of the vessel radially outwardly of the contact area.

2. A pressure vessel assembly according to claim 1 in which an annular ledge portion is provided on the uppermost edge of the fiange, the ledge portion being of greater diameter than the flange, the gasket also being bonded to the ledge portion, the bead portion being at least in part in registry with the ledge portion.

3. A pressure vessel assembly according to claim 1 or 2 wherein the bead portion and the other portions of the undersurface of said gasket member are biased by the nut into conforming engagement with the internal wall portions of the vessel radially outwardly of the said contact area.

4. A pressure vessel assembly according to any of claims 1 to 3 wherein the oil port assembly includes a valve seat and a valve member movably mounted therein and shiftable between sealing and unsealing positions relative to the said seat.

5. A pressure vessel assembly substantially as hereinbefore described with reference to the drawings.