BELLOWS TYPE VALVE ACTUATOR

摘要

An actuator system includes a fluid filled bellows 18 one end of which is fixed and the other end of which is connected to a movable member 14. A heater 22 is located within the bellows to heat the fluid therein thereby to cause expansion of the bellows and movement of the movable member 14. The heater 22 is of low thermal inertia and is a printed circuit type of heater which may be rolled to hollow cylindrical form to facilitate its location within the bellows.