Abstract: Improved techniques are provided for opening or closing an underwater valve in a subsea fluid pipeline utilizing an acoustic signal transmitted from the surface to a receiver adjacent the valve. A predetermined torquing force is applied to a shaft directly coupled to the valve stem, although rotation of the valve stem is prevented by the mechanical connection of an explosive bolt. Receipt of the transmitted acoustic signal initiates the release of stored electrical energy which detonates the explosive bolt and breaks the mechanical connection, thereby enabling the pre-existing torquing force to rotate the valve stem. Valve operation reliability is significantly increased, since the torquing force for operating the valve is applied before the valve is installed in the subsea environment.

Abstract: An improved hydraulic coupler suitable for interconnecting subsea fluid lines is provided with a radial seal between the male and female body portions. A C-shaped metallic seal is housed within the female body of the coupler, so that the seal may be checked or replaced if necessary between successive mating and unmating operations. An elastomeric secondary seal is also provided on the female body, and sealingly engages the same diameter cylindrical surface of the male coupler which is engaged by the C-shaped seal. A wiper member also mounted on the female body cleans this cylindrical surface as the body portions are brought together, thereby enhancing the reliability of both the elastomeric seal and the metallic seal. A guide for the valve poppet is threadably connected to a respective coupling body to increase reliability. Coupler halves may typically be housed within either a latchable subsea control module mounting base or a junction plate conventionally used in surface petroleum recovery operations.