GB2150247A

GB2150247A - Fluid flow couplings

Info

Publication number: GB2150247A
Application number: GB08432292A
Authority: GB
Inventors: Arthur Leighton Brake
Original assignee: Baj Vickers Ltd
Current assignee: Baj Vickers Ltd
Priority date: 1981-12-16
Filing date: 1984-12-20
Publication date: 1985-06-26
Also published as: GB2150247B; GB8432292D0; GB2112094B; GB2112094A

Abstract

A fluid flow coupling, particularly for pneumatic lines, comprising a first element (3) and a second element (31) each of which contains a valve retracting member (13, 36) having a flange which engages a spring-loaded valve member (16, 38) which, when the two elements are interengaged, abut each other to provide a through-flow path through the coupling. When the path is open the two valve retracting members engage to close a venting path (74) which is opened when the two elements come to be separated. The two elements are held together by balls (46) engaging in a groove (22) and held therein by a sleeve (47) which carries a second sleeve member (56) having teeth (61) which engage with teeth (62) on a sleeve member (23) carried on the element (3). When the teeth are engaged the coupling can only be moved towards the engaged condition and to release the coupling it is first necessary positively to manually draw back the sleeve (56) to disengage the ratchet teeth. It is thus not possible to disconnect the coupling inadvertently and it is not possible to disconnect the coupling when the space between the two halves of the coupling contains fluid under pressure. <IMAGE>

Description

SPECIFICATION Fluid flow couplings This invention relates to fluid flow couplings and is particularly, although not exclusively, concerned with self-sealing couplings for high pressure gases, for example oxygen at a pressure of 2000 psi (13,800 kPa).

The invention is seen to reside in any of the following features individually or in any compatible combination or in any of the novel features of the specific example to be described below, taken individually or in any compatible combination or in any compatible combination with any one or more of the following features.

The coupling comprises two parts each comprising a body containing a valve and a sleeve, each sleeve being reciprocatable on the respective body and one being rotatable thereon, the sleeves having interengaging locking means, such as male and female screwthreads, one of the bodies having a retractable detent which is engageable in detent receiving means in the other body, the sleeve on the said one body acting, when the locking means are interengaged, to prevent retraction of the detent.

Thus the detent may be a ball carried in an aperture extending through the respective body to engage in a groove or other recess in the other body.

Separation thus proceeds in two stages, the first being disengagement of the two sleeves, as by unthreading them from one another, and the second being release of the detent by further movement of one of the sleeves after the first stage is complete.

The coupling comprises two parts each comprising a body containing a valve and means for connecting the two parts together to provide a flow path through the two valves and an intermediate space between the valves, there being a vent path from the intermediate space to the outside and means closing the path when the connecting means are fully operative and, during disconnection, opening the path before the connecting means permit separation ofthetwo parts. For example, connecting means may comprise cooperating screwthreads and the closing means may comprise a sleeve portion on one body which passes over a spigot portion on the other body, the path opening into one of the facing surfaces of the sleeve portion and the spigot portion.

The coupling comprises two parts each comprising: a body comprising a sleeve portion and a boss portion supported within the bore of the sleeve portion; and a valve member axially reciprocatable on the boss portion and biased into engagement with an inwardly directed circumferential surface in the bore of the sleeve portion to afford a valve. Each valve member may have a projecting portion which, when the two parts are connected together, engage one another to move the two valve members off their respective circumferential surfaces to open the valves. The circumferential surfaces may be conical surfaces cooperating with conical surfaces on the valve members.

The coupling comprises two parts, the first of which carries a first screwthread and the second of which mounts a sleeve rotatable thereon and carrying a second screwthread complementary to the first screwthread, the first part carrying a ratchet member, the sleeve and the ratchet carrying complementary releasable ratchet means which, when engaged, permit rotation of the sleeve to connect the two parts together but prevents rotation of the sleeve in the opposite direction. The ratchet member may be a sleeve which is axially movable on but non-rotatable on the first part and carries teeth which complement teeth on the sleeve; the teeth may, for example, be of sawtooth profile. The ratchet member may be spring biased towards the sleeve.

The invention may be carried into practice in various ways but one self-sealing coupling will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows the coupling at an early stage of connection, in half longitudinal section; Figure 2 and 3 show the coupling in two successive further stages of connection; Figure 4 shows the fully connected coupling; and Figure 5 is front elevation to a smaller scale of the fully connected coupling.

The coupling shown in the drawings is intended to connect, on the one hand, a high pressure discharge line to be attached to the right hand end of the right hand part 1 of the coupling to, on the other hand, a device which is intended to supply the pressurised gas and is to be connected to the left hand end of the left hand part 2 of the coupling. The coupling being described is for use at pressures up to 2000 psi (13,800 kPa).

The right hand part 1 of the coupling comprises a body portion 3 having a central bore 4 within which a central boss portion 5 is supported by an integral diaphragm wall 6 formed with openings 7. The part of the bore to the right of the diaphragm wall 6 is formed with a female thread 8 to receive a male union member to which a flexible discharge hose is connected. Within the central portion of the bore 4 is a right hand valve retraction member 11 which is permanently secured in the valve body 3 by screw threads 12. The left hand end of the valve retraction member 11 is formed with a flange portion 13 having a conical valve seat 14 which engages a conical surface 15 on a right hand valve member 16 which has a sleeve portion 17 surrounding part of the boss portion 5.Interposed between a shoulder 18 on the boss portion and a surface 19 on the valve member 16 is a compression spring 21 which biases the valve member 16 to the left as seen in the drawing.

The exterior surface of the body portion 3 is formed with an exterior groove 22 to receive detent balls as will be described.

Rotating on the outside of the body portion 3 is a right hand ratchet sleeve 23 having an inwardly directed collar portion 24 which is trapped between a shoulder 25 on the body portion 3 and a circlip 26 secured in a groove in the body portion so that the ratchet sleeve 23 is free to move axially on the body portion 3 as well as free to rotate thereon.

The left hand part 2 of the coupling has parts which are somewhat similar to their counterparts in the right hand part and thus the left hand part 2 includes a body portion 31 having a bore 32 the left hand end of which is formed with female screw thread 33 to receive a boss 34 having a bore 35 leading from a point of supply. Within the bore 32 is a left hand valve retraction member 36 which is secured to the body member 31 by screw threads 37. A left hand valve member 38 has a conical surface 39 which cooperates with a conical surface 41 on the valve retraction member 36 and has a sleeve portion 42 surrounding the boss portion 43 of the body member 31. The valve member 38 is biased to the right as seen in the drawings by a compression spring 44.

Towards the right hand extremity of the body portion 31 is a series of apertures 45 containing detent balls 46 which are retained by a ball retaining sleeve 47 which is axially slideable on the outside of the body portion 31 between a position in which an inwardly directed shoulder 48 engages a collar 49 on the body portion 31 and a position in which an inwardly directed integral collar 51 on the ball retaining sleeve 47 engages a shoulder 52 on the body portion 31. A coil spring 53 biases the ball retaining sleeve 47 to the right as seen in the drawings. The ball retaining sleeve 47 is formed at the right hand end with a male screw thread 54 which can cooperate with a female screw thread 55 on the ratchet sleeve 23 of the right hand part 1 of the coupling.

Surrounding the ball retaining sleeve 47 is a second ratchet sleeve 56 which is axially movable on the ball retaining sleeve 47 by means of interengaging splines 57, the ratchet sleeve 56 being biased to the right as seen in the drawing by a compression coil spring 58. The right hand end of the ratchet sleeve 56 and the left hand end of the ratchet sleeve 23 carry complementary ratchet teeth 61 and 62 respectively which are so shaped that when the teeth are engaged with one another and the screw threads 54 and 55 are engaged with one another the ratchet sleeve 23 can be rotated in a direction such that the screw threads will draw the ratchet sleeve 23 and the ball retaining sleeve 47 towards one another while the teeth 61 click past the teeth 62 but rotation of the ratchet sleeve 23 in the unscrewing direction is not possible without manual retraction of the ratchet sleeve 56 against the bias of the spring 58 in the direction of the arrow 63.

Operation of the coupling is as follows. Itwill be seen from examination of Figure 1 that flow from the supply is prevented by engagement of the conical surfaces 39 and 41 on the valve retaining member 36 and the valve member 38 respectively and by means of an O-ring 65 between the valve retraction member 36 and the body portion 31.

Similarly flow out of the device using the gas is prevented by engagement between surfaces 14 and 15 on the valve member16and on the valve retraction member 11 respectively and by an O-ring between the valve retraction member 11 and the body member 3.

Figure 1 shows that the detent balls 46 are retracted into a groove 66 in the ball retaining sleeve 47 thus allowing the left hand end 67 of the body portion 3 of the right hand coupling part 1 to enter the right hand end of the bore 32 of the body member 31 of the left hand part 2. As the right hand part 1 is moved to the left, the detent balls 46 will reach the region of the groove 22 and can then move radially inwards so that the spring 53 will move the detent retaining sleeve 47 to the right to the position shown in Figure 2 thus moving the groove 66 out of alignment with the detent balls 46 so that the balls are locked into the groove 22 and the two parts of the coupling are locked together.

The sleeve 23 which is knurled on its outside surface 68 is then moved to the left and the screw thread 55 engaged with the screw thread 54 and the ratchet sleeve 23 is rotated so that the ratchet sleeve 23 is moved further to the left thus drawing the body portion 3 further to the left as is indicated in Figure 3. At this stage the two valve members 16 and 38 have engaged one another, the left hand valve member 38 being moved to the left until its left hand end 69 engages a shoulder 70 on the boss portion 43 of the left hand body portion 31.Continued rotation of the ratchet sleeve 23 will continue moving the right hand part of the coupling to the left until, as shown in Figure 3, the two valve retraction members 13 and 36 engage one another by which time the conical surfaces on the valve retraction members and the members will have separated to produce passages 71 and 72 between them, thus providing an open passage through the coupling from the supply on the left to the point of use on the right. Continued rotation of the ratchet sleeve 23 will cause the ratchet teeth 62 to engage the ratchet teeth 61, this rotation being permitted by the teeth 62 and 61 camming on each other and moving the ratchet sleeve 56 to the left as the sleeve 23 rotates through each tooth pitch. The coupling is now in the condition shown in Figures 4 and 5.

Disengagement of the coupling proceeds generally through the reverse series of operations.

Initially the ratchet sleeve 56 must be retracted manually to the left, i.e. in the direction of the arrow 63, so that the teeth 61 clear the teeth 62 before the separation operation can be commenced. The ratchet sleeve 23 is then rotated in the unscrewing direction. At an intermediate stage, the condition shown in Figure 2 is reached where the conical surfaces on the valve retraction members have engaged their respective valve members to close the passages 71 and 72 thus sealing the supply on the one hand and the user device on the other hand.

At this stage the intermediate space 73 between the valve retraction members and between the valve members is vented to atmosphere through a passage 74 in the left hand valve retraction member 36, a groove 75 on the outside of the valve retraction member, a clearance 76 between the right hand body member 3 and the left hand body member 31, a space 77 between the right hand body member 3 and the right hand ratchet sleeve 23 and a vent passage 78 extending through the ratchet sleeve 23.

At this stage it will be seen from Figure 2 that the detent balls 46 are still trapped in the groove 22 so that the two parts of the coupling cannot separate. If for any reason the valves provided by the valve members 16 and 38 and the valve retraction members 13 and 36 should not have closed as they should have done, gas will be vented through the path described to give an audible indication that valve closure has not occurred. It will be seen from Figures 3 and 4 that when the coupling is fully connected the vent path is sealed by an O-ring 79 held in a groove in the left hand end 67 of the right hand body portion 3. When any residual gas in the intermediate space 73 has been vented and it is clear that the valves have closed, the ratchet sleeve 23 is is further rotated to separate it from the ball retaining sleeve 47 thus producing first stage separation and allowing the ball retaining sleeve 47 to be moved to the left until the groove 66 is aligned with the detent balls 46 thus permitting them to move radially outwards from the groove 22 and allowing second stage separation so that the right hand part of the coupling can be completely removed from the left hand part.

Claims

1. A fluid flow coupling comprising comprising two parts, the first of which carries a first screwthread and the second of which mounts a sleeve rotatable thereon and carrying a second screwthread complementary to the first screwthread, the first part carrying a ratchet member, the sleeve and the ratchet member carrying complementary releasable ratchet means which, when engaged, permit rotation of the sleeve to connect the two parts together but prevents rotation of the sleeve in the opposite direction.

2. A coupling as claimed in Claim 1 in which the ratchet member is a sleeve which is axially movable on but non-rotatable on the first part and carries teeth which complement teeth on the sleeve.

3. A coupling as claimed in Claim 2 in which the teeth are of sawtooth profile.

4. A coupling as claimed in Claim 2 or Claim 3 in which the ratchet member is spring biased towards the sleeve.

5. A fluid flow coupling comprising two parts each comprising a body containing a valve, the two parts when connected having a space between the valves and arranged such that on disconnection of the two parts each of the two valves automatically closes, the interspace is vented to the surrounding atmosphere and the two parts are then separable.

6. A fluid flow coupling comprising two parts each comprising a body containing a valve and a sleeve, each sleeve being reciprocatable on the respective body and one being rotatable thereon, the sleeves having interengaging locking means, such as male and female screwthreads, one of the bodies having a retractable detent which is engageable in detent receiving means in the other body, the sleeve on the said one body acting, when the locking means are interengaged, to prevent retraction of the detent.

7. A coupling as claimed in Claim 6 in which the interengaging locking means comprises male and female screw threads.

8. A coupling as claimed in Claim 6 or Claim 7 in which the detent is a ball carried in an aperture extending through the respective body to engage in a recess in the other body.

9. A coupling as claimed in Claim 8 in which the recess comprises a circumferential groove.

10. Afluid flow coupling comprising two parts each comprising a body containing a valve and means for connecting the two parts together to provide a flow path through the two valves and an intermediate space between the valves, there being a vent path from the intermediate space to the outside and means closing the path when the connecting means are fully operative and, during disconnection, opening the path before the connecting means permit separation of the two paths.

11. A coupling as claimed in Claim 10 in which the connecting means comprises cooperating screw threads.

12. A coupling as claimed in Claim 10 or Claim 11 in which the closing means comprises a sleeve portion on one body which passes over a spigot portion on the other body, the path opening into one of the facing surfaces of the sleeve portion and the spigot portion.

13. A fluid flow coupling comprising two parts each comprising a sleeve portion and a boss portion supported within the bore of the sleeve portion; and a valve member axially reciprocatable on the boss portion and biased into engagement with an inwardly directed circumferential surface in the bore of the sleeve portion to afford a valve.

14. A coupling as claimed in Claim 13 in which each valve member has a projecting portion which, when the two parts are connected together, engage one another to move the two valve members off their respective circumferential surfaces to open the valves.

15. A coupling as claimed in Claim 13 or Claim 14 which the circumferential surfaces are conical surfaces cooperating with the conical surfaces on the valve member.

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