Source: {"pile_set_name": "USPTO Backgrounds"}

1. Field Of The Invention
This invention relates in general to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, this invention involves a hydraulic coupling having a hollow metal seal retained in the female member upon separation of the coupling members.
2. Description of the Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with sealed passageways connected therebetween. The female member generally is a cylindrical body with a relatively large diameter longitudinal bore at one end and relatively small diameter longitudinal bore at the other. The small bore facilitates a connection to hydraulic lines, while the large bore seals and slidingly engages the male member of the coupling. The male member includes a cylindrical portion at one end having an outer diameter approximately equal to the diameter of the large bore of the female member of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to various embodiments of the device, fluid flow is established between the male and female members. Couplings of this type are shown in U.S. Pat. No. 4,694,859 to Robert E. Smith III, and other patents owned by National Coupling Company, Inc. of Stafford, Tex.
In undersea drilling and production applications, the male member of the coupling may be connected to a manifold plate or other securement at a subsea location at the inside or outside of the well bore. In many cases, the male members are positioned so that the end or leading face of each member faces up from the sea floor. The female members, which also may be secured to a manifold plate, are moved into position over the male members and then lowered onto the male members by a diver or subsea vehicle. When the female members are positioned on the male members, hydraulic fluid flow typically is from the female member to the male member of each coupling.
The male and female members typically have poppet valves which are spring biased to the closed position. The poppet valve typically includes a conical valve face which seats, in the closed positioned, against a valve seat in the coupling member. The poppet valve opens to allow fluid flow, and closes against the valve seat within the bore to arrest the flow. The valve may includes a valve actuator which may be a nose or stem extending from the apex of the valve face along the longitudinal axis of the poppet valve.
U.S. Pat. No. 4,694,859 shows a hollow metal seal in a coupling of the foregoing type. Fluid pressure in the coupling urges the inner circumference of the seal radially inwardly to seal with the male member. The seal is retained in the female member bore by a seal retainer, which may be a sleeve insertable into the female member bore or threaded to the female member to abut the metal seal.