Patent attributes
Disclosed is a pneumatic actuator movement indicator comprising a housing adapted to be connected in series between a pneumatic actuator and a source of pressurized fluid for the actuator, and an indicator located in, and having an equilibrium position in, the housing. The housing includes a first chamber for placing the housing in fluid communication with said actuator at a pressure P1, and a second chamber for placing the housing in fluid communication with said source of pressurized fluid at a pressure P2. The indicator is movable in the housing in response to a difference between P1 and P2. Movement of the pneumatic actuator produces a difference between P1 and P2; and in response to this difference, the indicator moves away from its equilibrium position, indicating the movement of the pneumatic actuator.
