GB2038970A

GB2038970A - Fluid flow couplings

Info

Publication number: GB2038970A
Application number: GB7939640A
Authority: GB
Original assignee: Baj Vickers Ltd
Current assignee: Baj Vickers Ltd
Priority date: 1978-11-15
Filing date: 1979-11-15
Publication date: 1980-07-30
Also published as: FR2441793A1; DE2946190A1; FR2441793B1; GB2038970B

Abstract

A fluid flow coupling providing a mounting and a valve operating means for pressure vessels for compressed gases comprises a tubular body (18) having a socket in which the neck of a gas bottle (1) can be locked by balls (44) carried in a sleeve (36) which can be moved axially by a cam (16) which extends across the bore of the body and is rotatable by a handle. The cam also moves one part (35) of a valve actuating member the other part (56) of which extends into the neck of the gas bottle to open the valve (65, 66) therein. The handle has three positions. In the first the balls are retracted to allow removal of the bottle. In the second the bottle is locked in position with its valve closed and a flow path exists from the outlet port to the atmosphere. In the third the valve in the bottle is open and a flow path exists from the bottle to the outlet port. <IMAGE>

Description

SPECIFICATION Fluid flow couplings This invention relates to fluid flow couplings and particularly, although not exclusively, to the mounting of pressure vessels for compressed gas.

The invention is particularly applicable to vessels for gases of very high pressures of, for example, at least 20 MPa.

According to the present invention, a fluid flow coupling comprises a tubular body having at one end a socket to receive a neck containing a valve, locking means on the socket to lock the neck in the socket, and a cam member within the tubular member and rotatable from outside the cam member to move axially an actuating member for the valve, the locking means comprising a sleeve which surrounds the valve actuating member and is also axially movable by the cam member so that the locking means are locked when the cam is in the valve opening position.

Preferably, the valve actuating member comprises a first part engaged by the cam and a second part which is arranged to actuate the valve, the two parts being axially movable relative to one another and providing, when the cam is in the valve opening position, a flow path from the socket to an exit from the housing and providing, when the cam is in an intermediate position between the valve operating position and a position in which the locking means in unlocked, a flow passage between the exit and the outside.

The invention may be carried into practice in various ways but a pressure vessel and mounting embodying the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a front elevation of the pressure vessel; Figure 2 is a front elevation showing the positions through which the cam operating lever moves and the housing in which the pressure vessel is mounted; Figure 3 is a plan section through the cam and the housing in which it is located; Figure 4 is a section on the line B-B of Figure 3 with the pressure vessel releasably mounted in the housing; Figure 5 is a section on the line A-A of Figure 3 with the pressure vessel securely mounted in the housing but with the pressure vessel sealed;; Figure 6 is a section on the line B-B of Figure 3 with the pressure vessel securely mounted in the housing with the pressure vessel communicating with the supply point; and Figure 7 is an exploded isometric view of the housing in which the pressure vessel is mounted.

Figure 1 shows a pressure vessel 1 intended to carry gas at approximately 8,000 pounds per square inch (50 MPa) when fully charged. The pressure vessel has a neck 2 which is formed on its outer surface with a first cylindrical surface 3, a groove 4, a second cylindrical surface 5 and a decreasing diameter portion 6 furthest away from the first cylindrical surface 3.

The pressure vessel 1 can be secured to a mounting 200 as shown in Figures 4, 5 and 6. As will be described, the mounting has means for locking the pressure vessel in position and means for opening the valve in the neck of the pressure vessel to allow the contents to pass to a supply point. Certain components of the mounting are shown isometrically in Figure 7.

Figure 2 shows a cam operating lever 7 mounted on an annular housing 8. The cam operating lever 7 rotates about an axis 9 and is designed to have three operating positions shown by arrows 10, 11 and 12. The operating position shown by the arrow 10 is to be termed the "bottle release" position, the operating position shown by the arrow 11 is to be termed the "off" position, and the operating position shown by the arrow 12 is to be termed the "on" position.

The annular housing 8 has an axis 13 which does not intersect the axis 9. The annular housing 8 is formed with an upper tubular portion 14, a cylindrical tubular portion 15, through which a cam 16 is rotatably mounted (see Figure 3), a cylindrical tubular portion 17 and a cylindrical tubular portion 1 8 of greater external diameter than the tubular portions 14 and 17.

The cam operating lever 7, as shown in Figure 3, is formed integrally with an annular portion 19, a cylindrical portion 20 of smaller diameter than the annular portion 19 and formed with an annular groove 21, a cylindrical portion 22, which is connected to the cylindrical portion 20 by the cam 16, and a threaded cylindrical portion 23 of smaller diameter than the cylindrical oortion 22.

The cylindrical tubular portion 15 is formed with ports 24 and 25 in its circumferential wall which are designed to recieve the cylindrical portions 20 and 22, respectively. The ports 24 and 25 are positioned such that the axis 9 about which the cam m 16 rotates does not intersect the axis 13 of the annular housing 8 but is spaced by a distance d. The port 25 is formed with an annular groove 26, and seated in the annular grooves 21 and 26 are seals 27 and 28 respectively.

A shoulder 28a of the annular portion 19 cooperates with a shoulder 29 of the cylindrical tubular portion 15, and a nut 30 is attached to the threaded cylindrical portion 23 and is designed to cooperate with a surface 31 of the cylindrical tubular portion 15.

An indexing device includes a bore 32 formed in the shoulder 29 and containing a spring 33 biasing a ball 34 towards the shoulder 28a.

Formed in the shoulder 28a are two recesses 34a (only one of which is shown) which cooperate with the ball 34 when the cam 16 is in either the "on" position or the "off" position.

Figure 4 is a section on the line B-B of Figure 3 and shows the pressure vessel 1 free for movement along the axis 13 (ire. the "bottle release" position). The inside surface of the tubular portion 18 is formed with a female screw thread 39. A tubular insert 40 is formed with a male screw thread 41 on its exterior surface which cooperates with the female screw thread 39 of the cylindrical tubular portion 18. The tubular insert 40 butts against the shoulder bounding the inner end of the tubular portion 1 8 and its inner edge is formed with a bevel 42.

Located inside the annular housing 8 are a piston 35 and a sleeve 36. The external surface of the sleeve 36 cooperates with the internal suface 37 of the annular housing 8. The sleeve 36 is formed with ports 38 through which the cam 16 extends.

The sleeve 36 is biased towards the cylindrical tubular portion 18 by a spring 101. The sleeve 36, in the region of the tubular portion 1 8, is formed with a series of passages 43 each containing a detent ball 44 of the same diameter as the thickness of the sleeve 36. The external diameter of the sleeve 36 is decreased after the portion containing the passages 43, to cooperate with the internal surface of the tubular insert 40.

Extending across the bore of the sleeve 36, in the region between the ports 38 and the passages 43, there is a wall 45 carrying a boss 47, the wall and the boss being formed with a central passage 46 having a seat 48. Extending through the wall 45 is a ring of passages 104.

The piston 35 is a tubular structure and is slidably mounted inside the sleeve 36. The piston 35 is formed with an end surface 103 and ports 49 through which the cam 16 passes, the walls of the ports 49 being designed to cooperate with the cam 16.

The external surface of the piston 35, in the region of the boss 47, is formed with an annular groove 50 containing a seal 100. The internal diameter of the piston 35 is greater than the external diameter of the boss 47.

Extending across the bore of the piston 35, in the region between the ports 49 and the annular groove 50, there is a wall 51 containing a stepped bore the first part 52 of which terminates in a seat 53 and the second part 54 of which is of larger diameter and contains a silencer 55.

Axially movable in the passage 46 of the wall 45 is a valve operating member 56 formed with an enlarged rounded head portion 57 and a central passage 58: The head portion 57 has a seat 105 designed to cooperate with the seat 48 and a seat 59 designed to cooperate with the seat 53. At the other end of the valve operating member 56 from the head portion 57 the central passage 58 is connected to the outside surface of the valve operating member by a series of diametrical slots 60 and the valve operating member 56 has a tip portion 102 at this end.

The neck 2 of the pressure vessel 1 is formed with a decreasing-diameter portion 61 at its outermost end leading to a passage 62 which cooperates with the valve operating member 56, and is formed with an annular groove 63 containing a seal 64. At the opposite end of the passage 62 from the decreasing-diameter portion 61 there is a seat 65.

A ball 66 is biased towards the seat 65 by a spring 67 (see Figure 5) to seal the pressure vessel 1 when not in use.

Operation of the assembly will now be described. When the cam operating lever 7 is in the "bottle release" position (Figure 4) the cam 16 holds the sleeve 36 against the force of the spring 101 leaving the detent balls 44 finish with the inside surface of the sleeve 36. The neck 2 of the pressure vessel 1 is then free to be inserted into the cylindrical tubular portion 18 and the sleeve 36. Rotation of the cam operating lever 7 to the "off" position as seen in Figure 5 allows the spring 101 to move the sleeve 36 towards the pressure vessel 1 causing the detent balls 44 to traver along the bevel 42 of the tubular insert 40 to eventually lie on the inside surface of the tubular insert 40.In this position they cooperate with the groove 4 of the neck 2 and in this arrangement the detent balls 44 have a smaller internal diameter than the first cylindrical surface 3 and the second cylindrical surface Son the outer surface of the neck 2. Once the pressure vessel 1 and the neck 2 are in the "off" position it is not possible to withdraw them from the mounting since this would tend to move the sleeve 36, with the force of the spring 101, against the cam 16. is possible to insert the neck 2 of the pressure vessel 1 into the cylindrical tubular portion 15 when the cam operating lever 7 is in the "off" position.This causes the decreasing diameter portion 6 of the neck 2 to bear against the detent balls 44 to force the sleeve 36 to move against the force of the spring 101 until the detent balls 44 have started travelling along the bevel 42. At the point where the detent balls have an equal internal diameter to the second cylindrical surface 5, the sleeve 36 ceases to move until the groove 4 of the neck 2 cooperates with the detent balls 44 and the sleeve 36 is able to travel, with the action of the spring 101, towards the pressure vessel 1 until the walls of the ports 38 contact the cam 16 as shown in Figure 5.

Rotation of the cam operating lever 7 from the "off" position to the "on" position, as shown in Figure 6, causes the cam 16 to bear against the opposite face of the ports 38 to lock the sleeve 36 in its position towards the pressure vessel 1. The rotation of the cam 16 also causes the piston 35 to travel towards the pressure vessel 1 and as the piston 35 moves the seat 53 contacts the seat 59 of the enlarged rounded head portion 57 of the valve operating member 56. Further rotation of the cam 16 towards the "on" position causes the tip portion 102 of the valve operating member 56 to bear against the ball 66 in the neck 2 and lift it off the seat 65.

Communication of the inside of the pressure vessel 1 to a supply point 68 is then achieved via the diametrical slots 60, the central passage 58 of the valve operating member 56, the first passage 52, the second passage 54 containing the silencer 55, around the cam 16 and through the tubular piston 35 to the supply point 68.

Once the supply point 68 is pressurised, the area on which pressure acts at the end surface 103 of the piston 35 is greater than the area of the tip portion 102 of the valve operating member 56 on which the same pressure also acts: the force of the spring 67 acting on the ball 66 and the resultant force acting on the piston 35 causes the piston to move towards the pressure vessel 1 until the seat 105 of the enlarged rounded head portion 57 cooperates with the seat 48 of the wall 45. The walls of the ports 49 in the piston 35 are now clear of the cam 16.

A pressure gauge is provided on the cam operating lever 7 (see Figures 2 and 3) in the form of a Bourdon tube 69 which is pressurised by a passage 70 in the annular portion 19 of the cam operating lever and a passage 71 through the cylindrical portion 20.

When the cam operating lever 7 is turned from the "on" position to the "off" position two forms of motion for the piston 35 and the valve operating member 56 can occur.

The first form of motion is that the rounded head portion 57 can remain with the seat 53 as the piston 35 is withdrawn from the pressure vessel 1 by the cam 16 until the ball 66 reaches the seat 65. When this occurs the force from the spring 67 on the tip portion 102 is removed and, as equal pressures act on a first area on the rounded head portion 57 defined by the passage 52 and a second area defined by the tip portion 102, the said first area being larger than the said second area, the valve operating member 56 moves towards the pressure vessel 1 to connect the supply point 68 to the atmosphere around the outside of the rounded head portion 57 and the passages 104 in the wall 45.

The second form of motion is that as the piston 35 is withdrawn the rounded head 57 remains with the seat 48 in contact with the seat 105 as the force of the pressure acting on the rounded head portion 57, the area of which is defined by the passage 52, is greater than the combined forces from the pressure and the spring 67 acting on the tip portion 102. As soon as the seat 59 is separated from the seat 53 the supply point 68 is vented to atmosphere as before and the valve operating member moves towards the piston 35.

Claims

1. A fluid flow coupling comprising a tubular body having at one end a socket to receive a neck containing a valve, locking means on the socket to lock the neck in the socket, and a cam member within the tubular member and rotatable from outside the cam member to move axially an actuating member for the valve, the locking means comprising a sleeve which surrounds the valve actuating member and is also axially movable by the cam member so that the locking means are locked when the cam is in the valve opening position.

2. A coupling as claimed in Claim 1 in which the valve actuating member comprises a first part engaged by the cam and a second part which is arranged to actuate the valve, the two parts being axially movable relative to one another and providing, when the cam is in the valve opening position, a flow path from the socket to an exit from the housing and providing, when the cam is in an intermediate position between the valve operating position and a position in which the locking means is unlocked, a flow passage between the exit and the outside.

3. A coupling as claimed in Claim 2 in which each part of the valve actuating member is axially slidable in a respective bore in the sleeve.

4. A coupling as claimed in Claim 3 in which the first part of the valve actuating member has an axial bore formed with a seat and the second part has a head which cooperates with the seat.

5. A coupling as claimed in any of the preceding claims in which the cam member is a bar which extends across the bore of the tubular body through openings in the sleeve and the valve actuating member.

6. A coupling as claimed in Claim 5 in which the axis of rotation of the bar is perpendicular to and offset from the longitudinal axis of the tubular body.

7. A coupling as claimed in any of the preceding claims in which the sleeve has radial bores containing balls and the bore of the tubular body has a step by which the balls are forced radially inwards as the sleeve is moved by the cam as the cam is moved from the unlocked position to the valve opening position.

8. A coupling as claimed in any of the preceding claims in combination with a compressed gas bottle having a neck locked in the socket of the coupling.

9. A coupling as claimed in Claim 8 in which the coupling is capable of handling gas at a pressure of 20 MPa.

10. A fluid flow coupling substantially as described herein with reference to the accompanying drawings.