Underwater buoyancy apparatus

摘要

A device for venting gas from an expansible gas chamber (lifejacket, lifting bag, etc.) of an underwater buoyancy apparatus. The device comprises a monitoring device which monitors the rate of ascent of the expansible gas chamber and provides a control signal when the ascent velocity exceeds a predetermined speed. A venting valve assembly controls the venting of gas from the expansible gas chamber and is responsive to the control signal to vent gas reducing the buoyancy of the expansible gas chamber.