Valve actuator with vent

A valve comprising:

• a) a valve body defining a piston recess in an end of the valve body and a valve member recess defined in the valve body;
• b) a piston disposed in the piston recess;
• c) a valve member disposed in the valve member recess;
• d) a sealed passage that extends from the piston recess to the valve member recess;
• e) a vent that extends from the sealed passage to an external surface;
• f) the sealed passage extends between the piston recess and the valve member recess and the piston is coupled to the valve member by a shaft disposed in the sealed passage, and the valve member and piston are moveable between a first position and a second position, wherein the piston extends past the end of the valve body when the piston and the valve member are in the second position.

A valve actuating arrangement comprising:

• a valve body;
• a valve member comprising a shaft,
• a piston connected to the shaft;
• the valve member being movable by operation of the piston and being disposed in the valve body, the valve body comprising a valve chamber that provides fluid communication between an inlet passage, an outlet passage and a vent passage based on the position of the valve member, the valve member having an open and a closed position to control flow of process media between the inlet passage, the outlet passage and the vent passage in response to operation of the piston,
• the shaft being disposed in and extending through a sealed chamber, the sealed chamber being sealed at one end from the valve chamber and at another end from a piston chamber, the piston being disposed in the piston chamber,
• a vent that extends from the sealed chamber to an external surface, wherein the valve member and piston are moveable between a first position and a second position, and the piston extends past the end of the valve body when the valve member is in the open position.