Abstract: There is disclosed a test stand for the pressure testing of a valve which comprises a flat support table defining a valve testing station onto which a port of a valve can be placed, means provided in the support for directing fluid pressure medium into the port when the valve is placed on the support table, and a set of jaws uniformly spaced around the testing station and mounted for slidable movement in unison along respective radial guides between a release position in which a valve can be placed on, or removed from, the support table, and a holding position in which the jaws engage with the valve, or a part connected to the valve, in order to centralize the valve between the jaws on the testing station.

Abstract: An actuator head is provided for a pressure relief valve (1) having a valve element (11) spring biased to a closed position and arranged to be movable under the action of a fluid pressure medium in order to allow the escape of the fluid pressure medium through the valve for pressure relief purposes. The actuator head comprises an actuator (3) which is coupled with the valve element (11) and has a member (21) displaceable in response to fluid pressure applied thereto. A linkage (22, 19, 12) couples together the valve element (11) and the actuator (3) and has a lost-motion connection (72) which allows the valve element (11) to move against its spring biasing (13) for pressure relief purposes without imparting movement to the displaceable member (21) of the actuator (3). Biasing means (27) is arranged to oppose displacement of the displaceable member (21) of the actuator (3), and control means (4, 5) is provided to control the supply of fluid pressure to said displaceable member (21).