Abstract: A directional control valve comprises a spool which is movable in a chamber and which carries shear seals urged against a respective wall of the chamber, the spool being movable between a first position in which a fluid supply inlet is in communication with a functional outlet and a second position in which the fluid supply inlet is cut off from the functional outlet, and a safety piston which is spring-loaded towards engagement with the spool in a sense to move the spool to the second position. An intermediate piston is interposed between the spool and the safety piston so that the intermediate piston can allow relative movement between itself and the spool. The chamber includes a port coupled to a pressure transducer which can monitor the position of the valve spool or the function line pressure.

Abstract: A sub-sea coupling comprises a male probe coupler and a female receiver coupler containing mutually engageable poppet valves which have intermediate valve heads between nose and shank portions which seal with respect to the respective couplers. Each valve has a longitudinal passageway allowing balancing of the poppet valve with respect to external pressure. Further, the poppet valves have substantial equality in effective area between the valve portions and the nose and shank portions so that the poppet valve is substantially balanced with respect to line pressure in the line to which the coupler is connected. The arrangement gives a high resistance to the ingress of sea water to the couplers while substantially avoiding any hydraulic lock or wash-out during make-up and separation of the couplers.

Abstract: A sub-sea coupling comprises a female coupler which accommodates a conical metal seal and an adjacent striker constituted by a sliding ring. The female coupler also includes a U-section seal outwardly of the striker. A male coupler has a forward probe with an intermediate part of slightly greater diameter than the extreme forward part. A shoulder between the intermediate and extreme parts of the probe engages the striker to cause the conical seal to flatten and thereby to provide a metal-to-metal radial seal between the female coupler and the male coupler. The U-section seal provides a seal against the intermediate part of the probe before the striker is engaged and is also configured to provide no significant resistance to the ingress of seawater when the couplers are disengaged.