Abstract: Autonomous assistance device for a safety valve protecting a vessel under pressure and comprising a hollow body (13), a seat cooperating with a movable closure member fixed to a rod (9), and a calibrated spring (7) bearing against the rod (9) and against the valve body (13) to hold the closure member against the seat. The closure member rod (9) is extended into a casing (19) fastened to the body (13) and receives the additional thrust of a spring (51). The casing (19) constitutes in addition a pneumatic ram whose piston (53) can apply to the rod (9) a thrust opposite to and greater than that of the spring (51). The device feeding the ram (19) comprises an autonomous reservoir (33), a three-way solenoid valve (24) for feeding the ram or connecting it to atmosphere, and a manometer contact (39) mounted on the wall of the pressure vessel and adjusted to close the solenoid valve supply circuit when the pressure in the vessel reaches the adjusted pressure.

Abstract: Device for detecting the operation of a valve, comprising a movable member (15) connected kinematically to a movable part (6) fastened to the closure member of the valve. A detector (24, 25, 26) makes it possible to monitor the displacements or the position of the detection member (15). The detection member (15) has at least one part provided with a predetermined breaking point (20). The kinematic connection between the valve and the detection member (15) can thus be interrupted by the breaking of the member (15) in the event of the jamming of the latter. The invention is in particular applicable to safety valves in nuclear power stations.