VALVE

摘要

A valve has a valve member (17) that is moveable along a first axis in a valve chamber ( ) between an open position and a closed position. In the open position the valve member is displaced from the valve seat such that a fluid inlet (pi) is connected to a fluid outlet (p2). In the closed position the valve member (17) is sealed against the valve seat so that the fluid path is closed. First (12) and second (46) opposed stacks of disc spring apply unequal loading resulting in a biasing force that biases the valve member towards the closed position. A first piston member (15) is movable in a first bore (14) relative to the valve member (17) and for moving the valve member in a first direction along the first axis. A second piston member (16) is movable in a second bore relative to the valve member (17) for moving the valve member along the first axis in a second direction opposite to the first direction. A first pressure compensation passage (71) extends between the fluid inlet (pi) and the first bore (14) such that the first piston member (15) is actuable by the fluid pressure in the fluid inlet (pi). A second pressure compensation passage (70) extends between the fluid outlet (p2) and the second bore such that the second piston member (16) is actuable by the fluid pressure in the fluid outlet. An actuator moves the valve member from the closed position to the open position.