The present invention relates to a highly reliable male/female fluid coupling with an improved metallic seal for sealably maintaining fluid pressure after repeated mating and unmating operations and, more particularly, relates to an improved metallic seal coupling which allows for both axial and radial deviation between the coupling halves during the mating operation.
Conventional male/female couplings have long been used to sealingly join pressurized fluid lines. The coupling halves, when joined, automatically enable the fluid and/or fluid pressure to be transmitted through the coupling without a significant pressure differential. When unmated, the value stems in the body of each coupler half automatically seal the fluid within the coupler and its respective fluid line. Such couplers preferably are able to reliably maintain high fluid pressure after repeated mating and unmating operations.
The seal between the joined coupling halves may conventionally be provided by either an elastomeric or metallic member. The low cost, chemical inert quality and noncorrosive characteristics of elastomeric sealing materials has resulted in the commonplace use of such sealing members for many applications. Such elastomeric seals typically may be manufactured from natural or synthetic rubber, Teflon, nylon, PEEK, or similar materials.
In other applications, especially those wherein high reliability is paramount or the contained fluid is highly abrasive, metallic seals are preferable. One such application involves couplers commonly used in subsea petroleum recovery operations, wherein a plurality of coupler halves are mounted on respective control module mounting bases, so that clamping and unclamping of the bases mates and unmates the couplers and thereby interconnects numerous fluid pressure transmission lines.
One type of coupler suitable for reliably interconnecting fluid lines employs a metallic face seal. Sealing engagement is provided by a metallic seal sandwiched between surfaces of the coupler halves, with each sealing surface being generally perpendicular to the axis of the coupler. The metallic seal is permanently deformed into sealing engagement with each sealing surface by an axially directed mating force, and thus must be replaced between successive mating operations. A coupling with a reusable metallic radial seal is disclosed in U.S. patent application Ser. No. 908,593, hereby incorporated by reference.
One disadvantage of prior art metallic seal couplers is the expense and inherent decreased reliability associated with maintaining close tolerance between the sealing surfaces of the coupler halves. Close axial tolerances must be maintained between the surfaces for engagement with the face seal for the first coupler described above, and similarly close alignment or radial tolerance of the cylindrical surfaces for engagement with the radial seal is necessary for the second coupling described in U.S. patent application Ser. No. 908,593. These tolerance problems, although not particularly troublesome for many coupling operations, are particularly difficult and expensive to correct for remote coupling operations, such as petroleum subsea operations.
The disadvantages of the prior art are overcome by the present invention, and an improved coupler is hereinafter described with metallic seals positioned to allow for both axial and radial deviation between the coupling halves.