Apparatus for actuating a main valve where a sensor is connected to a sealed chamber and adapted to vent a pressurized fluid from the chamber in response to a sensed event

摘要

An apparatus for actuating a main valve 18 is described. The main valve 18 has an exposed component that is moveable along a line of travel from a first position to a second position. The main valve 18 also has an actuated state in which the exposed component is in the second position and a non-actuated state in which the exposed component is in the first position. The apparatus has a pilot valve 20. The pilot valve 20 has housing and a piston 58 disposed within the housing and movable between a deactivated position and an activated position along a pathway. The piston 58 separates the housing into a first sealed chamber 74 and a second sealed chamber 76. Both sealed chambers are sealed from air entry. The piston 58 moves to the activated position in response to a pressure drop in the first sealed chamber. A first contact is connected to the piston 58 and moves with the piston 58. The first contact urges the exposed component of the main valve 18 from the first position to the second position as the piston 58 moves from the deactivated position to the activated position. A sensor 94 is connected to the first sealed chamber 74 and is adapted to vent a pressurized fluid from the first sealed chamber 74 in response to a sensed event. A second contact is connected to and movable with the piston 58, and is adapted to be releasably fixed to the housing so as to releasably maintain the piston 58 in the deactivated state.