IMPROVEMENTS IN OR RELATING TO COUPLING ASSEMBLIES

Abstract: A coupling assembly, in particular for a cryogen supply line for cryosurgical apparatus, comprises a male coupling member (14) and a female coupling member (12). Sealing means for the assembly comprises a first rubber O ring (24) located internally on the female member and a second rubber O ring (30) located externally of the male member. When the male member is inserted into the female member the first and second coupling members define a closed chamber (32). Any cryogen leakage operates within the chamber thereby increasing the pressure therewithin and tending to prevent further leakage. The coupling members are secured together by means of corresponding screw threaded portions (41, 44).

Description: Improvements in or Relating to Coupling Assemblies This invention relates to coupling assemblies. In particular, the invention relates to coupling assemblies for cryogen supply lines such as are associated with cryosurgical apparatus- Known coupling assemblies for supply lines of cryogens, for example liquid nitrogen, comprise two parts which can be fastened together. The problem with such existing coupling assemblies is that there is leakage of the cryogen from the assembly. It is an objection of the invention to obviate and/or mitigate these and other disadvantages. According to this invention, there is provided a coupling assembly for a cryogen supply line, said assembly comprising first and second coupling members each defining a passageway for the cryogen, the first coupling member being adapted to receive the second coupling member such that the respective passageways are in register, and securing means to secure the first coupling member to the second coupling member. Preferably, the coupling assembly comprises seal- ing means to seal the assembly and to prevent leakage therefrom. The sealing means may comprise first and second sealing members which, when the first and second coupling members are secured together, define a closed chamber therebetween. Thus, if any cryogen leaks past the first sealing member, it passes into the chamber where it evaporates thereby increasing the pressure in the chamber to prevent further leakage. Preferably, the first and second coupling members have corresponding parallel portions and tapered portions such that the tapered portion on the first coupling member receives the tapered portion on the second coupling member. The first sealing member may comprise a first rubber ring on the first coupling member and the second sealing member may comprise a second rubber ring on the second coupling member. The first sealing member may be provided on the parallel portion of the first coupling member and the second sealing member may be provided on the tapered portion of the second coupling member. In the preferred embodiment, the first coupling member comprises a female member and the second coupling member comprises a male member, the female and male members being adapted to engage each other matingly. The securing means may comprise a screw threaded member on the second coupling member, which may be rotatable independently of the second coupling member. The securing means may further comprise corresponding screw threads on the first coupling member adapted to engage the threads on the screw threaded member. A first flange may be provided on the first coupling member, and a second flange may be provided on the screw threaded member. The flanges are adapted to engage each other when the screw threaded member is fully engaged with the screw threads on the first coupling member. An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawing in which:- Fig. 1 is a schematic sectional representation of a coupling assembly for a cryogen supply line; Fig. 2 is a drawing similar to Fig. 1 but with the first and second coupling members coupled together. The drawings show a coupling assembly generally designated 10 which comprises a female member 12 and a male member 14. The female member 12 is adapted to receive the male member 14. A passageway 16 for the cryogen extends through the female member and a similar passageway 18 extends through the male member. The inner wall of the female member 12 comprises a parallel portion 20 and a tapered portion 22. A seal in the form of a first rubber ring 24 is provided on the parallel portion 20. The outer wall of the male member 14 comprises a parallel portion 26 and a tapered portion 28. The tapered portion 22 on the female member and the tapered portion 28 on the male member correspond with each other in shape. A seal in the form of a second rubber ring 30 is provided on the tapered' portion 28 of the male member 14. When the male member 14 is received in the female member 12 a chamber 32 is defined between the first and second rubber rings and between the inner wall of the female member 12 and the outer wall of the male member 14. (See Fig. 2). The assembly also comprises a screw threaded member 40 which has external screw threads 41 and, at one end thereof, a flange 42. The female member 12 is provided with internal screw threads 44 at an end region thereof, and a flange 46. The screw threaded member 40 can be rotated independently of the male member 14. When the male member 14 has been received in the female member 12, the screw threaded member 40 can be threadably engaged with the screw threads 44 on the female member 12 (see Fig. 2). When the screw threaded member 40 is fully engaged with the screw threads 44 on the female member 12, the flanges 42, 46 engage each other. A cryogen supply line 50 (to supply, for example, liquid nitrogen) is connected to the female member 12 and a further cryogen supply line 52 is connected to the male member 14. In the embodiment shown, the cryogen supply flows in the direction of the arrow indicated at A. Modifications may be made to the assembly without departing from the scope of the invention. For example, the flange on the female member could be omitted and the flange on the male member could simply engage the end of the female member. Also, the male and female members could be swapped round such that the cryogen flows in the direction opposite to that of arrow A. The coupling members may have a different shape and configuration to that shown, or the sealing or securing means may be changed within the scope of the invention. Finally, whilst the invention is described with reference to a cryogen supply line for cryosurgical apparatus, it will be appreciated that the use of the invention is not limited to this field. Whilst endeavouring in the foregoing Specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims: Claims : - 1. A coupling assembly for a cryogen supply line, said assembly comprising first and second coupling members each defining a passageway for the cryogen, the first coupling member being adapted to receive the second coupling member such that the respective passage¬ ways are in register, and securing means to secure the first coupling member to the second coupling member. 2. A coupling assembly according to Claim 1, comprising sealing means to prevent leakage therefrom. 3. A coupling assembly according to Claim 2, wherein the sealing means comprises first and second sealing members which, when the first and second coupling members are secured together, define a closed chamber therebetween. 4. A coupling assembly according to Claim 2 or Claim 3 wherein the first sealing member comprises a first rubber ring on the first coupling member and the second sealing member comprises a second rubber ring on the second coupling member. 5. A coupling assembly according to any of the preceding Claims wherein the first and second coupling members have corresponding parallel portions and tapered portions such that the tapered portion on the first coupling member receives the tapered portion on the second coupling member. 6. A coupling assembly according to any of the preceding Claims wherein the securing means comprises a screw threaded member on the second coupling member and corresponding screw threads on the first coupling member adapted to engage the threads on the screw threaded member. 7. A coupling assembly according to Claim 6, wherein the screw threaded member is rotatable independently of the second coupling member. 8. A coupling assembly according to any of the preceding Claims wherein a first flange is provided on the first coupling member, and a second flange is provided on the second coupling member, the flanges being adapted to engage each other when the first and second coupling members are secured together. 9. A coupling assembly substantially as hereinbefore described with reference to the accompanying drawings. 10. Any novel subject matter or combination including novel subject matter disclosed, whether or not within the scope of or relating to the same invention as any of the preceding Claims.

Inventors: CLARKE BRIAN KEVIN RODERICK, CLARKE, BRIAN, KEVIN, RODERICK
Applicants: CRYOGENIC TECHNOLOGY LTD, CRYOGENIC TECHNOLOGY LIMITED
Application year: 1992
Main classification: A61M39
IPC codes: A61B18, A61F7, F16L19