GB2269872A - Butt-jointed pipe couplings with non-return valves - Google Patents

Abstract

A coupling for a fluid line has first and second interconnectible members (10, 12) each having a through passage (18, 20) with a spring urged valve member (46, 48) therein closing off the ends of the members which come into contact when the coupling is made. Each valve member (46, 48) has a forward projection (72, 74) which projections extend beyond said ends when the coupling is separated and contact each other to move the valve members (46, 48) off their seats (22, 24) when the coupling is made. <IMAGE>

Description

Improvements in or relating to couplings The present invention concerns improvements in or relating to couplings, especially but not exclusively hydraulic couplings.

In the use, for example, of hyraulically powered tools which require a source of high pressure fluid for their operation, there is often a need to disconnect the tool from the high pressure supply. Up to this time, couplings known as "quick release" couplings have been employed, the couplings involving the use of spring-loaded ball bearings on one part of the coupling engaging with an annular recess in another part of the coupling and pulling the coupling members together to ensure their fluid tightness.

Couplings of this nature have exhibited disadvantages not the least which is the cost of manufacture, difficulty in maintenance and tendency to partially or fully leak when subjected to particularly high pressures, for example, 2320 kg/sq.cm (33,000 lb/sq.in).

Furthermore, valves of this nature must have a high factor of safety, for example, of the order of 2#1:1. In existing valves this factor of safety is difficulty to achieve economically.

It is an object of the present invention to obviate or mitigate these disadvantages.

According to the present invention there is provided a coupling comprising first and second members each having means adapted to receive a fluid line, means for holding said members in end to end sealing relationship and fluid passage means therethrough adapted to communicate when said members and placed in end to end relationship, each passage being provided with a non-return valve preventing flow of fluid out of the member, each non-return valve having means for displacing it from its sealing position when the members are brought together.

Preferably the means for holding the members together comprises a threaded \collar rotatably mounted on one member and threadably connectable to the other member such that on screwing down the threaded collar the members are brought into closer end to end engagement.

Preferably the facing end faces of the members include seal means. Said seal means may comprise an annular recess in one member in which is housed an 0-ring seal and an anular protrusion from the other member adapted to penetrate said recess and compress said seal.

Preferably each non-return valve comprises a valve member movable in the passage through said member, resilient means for urging said valve member towards the outlet from the member, a sealing surface on the valve member engageable with a corresponding valve seat formed on the coupling member to close off said passage when the valve member seats on said valve seat and a projection extending from the valve member beyond the end of the member when the valve member is in its seated position.

Preferably stop means are included within the passage to restrict the movement of the valve member away from the passage opening in said end of the member.

Preferably each valve member is provided with passage means extending therethrough from the sealing surface to the end of the valve member opposite from its extension.

Am embodiment of the present invention will now be described by way of example only with reference to the accompanying drawing which shows a cross-section through an hydraulic coupling.

An hydraulic coupling comprises a male member 10 and a female member 12 each having a threaded bore 14,16 at its outer end to receive the threaded end of a flexible hydraulic pipe (not shown). Said threaded bores 14,16 lead into through passages 18,20 through the male and female members, said passages 18,20 reducing in size over a stepped inclined portion 22,24 defining a valve seat to outlet portions 26,28 at the inner end of the members. An internally threaded coupling nut 30 is freely rotatably mounted on the female member 12 and can slide over the outer surface of the member 12 between a retaining ring 32 and an outwardly directed step 36 towards the inner end of the member. The outer surface of the inner end of the male member 10 is provided with a thread 38 to receive the nut.

It will be realised that by placing the members in end to end relationship they can be held together by engaging the nut 30 on the threaded portion 38 and screwing it tightly down.

To increase the seal between the mating end faces of the male and female members when they are held down by the nut 30 the female member is provided with an annular recess 40 in which is housed an 0-ring seal 42. A corresponding anular protrusion 44 is formed in the end face of the male member and projects into the recess to compress the 0-ring seal to provide the necessary sealing effect between the end faces of the male and female members.

Each of the male and female member has a poppet valve 46,48 slidably mounted in the through passage 18,20.

The poppet valve is biassed towards the inner end of the member in which it is mounted by a coil spring 50,52 located in a recess 54,56 in the bottom of each poppet 46,48 and in a further recess 58,60 formed in a spring retainer 62,64 threadably mounted in the passages 18,20 at the base of the threaded bores 14,16, each retainer having a through passage 66,68 providing fluid communication between the threaded bore 14,16 and the passage 18,20. A hollow spacer 69,70 is provided in each passage extending from the end of the spring retainer 62,64.

Each poppet valve 46,48 is provided with a cylindrical forward extension 72,74 which, when the poppet is seated on the valve seat 22,24 extends beyond the end face of the coupling member in which it is mounted.

Between the extension 72,74 and the main body of the poppets 44,46 there is an inclined sealing surface 76,78 adapted to seat against the valve seats 22,24 when the poppets are in their fully extended positions under the influence of the springs 50,52.

To provide a passage for fluid through the poppet there is provided a diametral bore 80,82 extending across the inclined surface from one side to the other and in fluid communication with an axial bore 84,86 extending from the spring recess 54,56.

It will be realised that, with the supply of pressure fluid turbed off, as the two coupling members are brought together the projecting extension 72,74 of the poppets will abut and further movement together of the coupling members will force the poppets inwardly unseating them from the valve seats 22,24, thereby allowing passage of fluid through the coupling, when the supply is turned on, from the threaded bore 14through the passage 18 the poppet 46, the passage 26 to the passage 28 the poppet 48, the passage 20 and the bore 16' (or vice versa).

Clearly when the coupling is dismantled by unscrewing the nut 30 the pressure of fluid therein and the springs 50,52 will return the poppets to the closed position thereby preventing any leakage from either side of the coupling when it is dismantled.

If the coupling is connected when one side is supplied with pressure fluid and the other not so that the pressure fluid augments the spring force in holding the poppet against its seat, when the members are brought together the poppet on the non-pressurised side will move into the member until its rear face abuts the end of the spacer 69 or 70 at which point further movement of this poppet is not possible so that the pressurised poppet is pushed off its seat thereby permitting flow of fluid through the coupling.

Various modification can be made without departing from the scope of the invention for example, the various components can be assembled and manufactured in any convenient form provided that each had a sliding valve which is normally urged to the closed position towards the mating end faces of the respective members of the coupling and is moved to the open position when the couplings are brought together.

Thus, utilising the minimum of components the quickrelease coupling of the present invention provides a highly efficient leak proof coupling having a burst pressure of at least around 6680 kg/sq.cm (95,000 lb/sq.in).

In contrast to existing valves when subjected to the above pressure the poppet valves increase in their sealing effect with the body of the coupling. In past valves when such high pressures were encountered (that is pressures to meet with the factor of safety) the internal components of the valve tended to be blown out from the valve. The coupling of the present invention is simple to operate needing only spanners which are readily available. When it is split thereby uncoupling the source of hydraulic fluid from, for example, a tool there is no leakage from either side of the coupling and contamination on the meeting faces of the coupling has little if any effect on the efficiency of the coupling.

Claims (9)

Claims:

1. A coupling comprising first and second members each having means adapted to receive a fluid line, means for holding said members in end to end sealing relationship and fluid passage means therethrough adapted to communicate when said members and placed in end to end relationship, each passage being provided with a non-return valve preventing flow of fluid out of the member, each non-return valve having means for displacing it from its sealing position when the members are brought together.

2. A coupling as claimed in claim 1, in which the means for holding the members together comprises a threaded collar rotatably mounted on one member and threadably connectable to the other member such that on screwing down the threaded collar the members are brought into closer end to end engagement.

3. A coupling as claimed in claim 1 or claim 2, in which the facing end faces of the members include seal means.

4. A coupling as claimed in claim 3, in which said seal means comprises an annular recess in one member in which is housed an 0-ring seal and an anular protrusion from the other member adapted to penetrate said recess and compress said seal.

5. A coupling as claimed in any one of the preceding claims, in which each non-return valve comprises a valve member movable in the passage through said member, resilient means for urging said valve member towards the outlet from the member, a sealing surface on the valve member engageable with a corresponding valve seat formed on the coupling member to close off said passage when the valve member seats on said valve seat and a projection extending from the valve member beyond the end of the member when the valve member is in its seated position.

6. A coupling as claimed in any one of the preceding claims, in which stop means is' included within the passage to restrict the movement of the valve member away from the passage opening in said end of the member.

7. A coupling as claimed in any one of the preceding claims, in which each valve member is provided with passage means extending therethrough from the sealing surface to the end of the valve member opposite from its extension.

8. A coupling substantially as hereinbefore described with reference to the accompanying drawings.

9. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.