Pneumatic actuator (single acting)
SPRING RETURN ACTUATORS (SR) ISO 5211>
PRINCIPLE OF OPERATION
Pressure applied to Port'A' will cause the inner chambers to be pressurised, forcing the pistons outward to compress the springs.
The pinion is rotated counter counteil clockwise. Upon release of pressure through Port'A' the springs will exert pressure to close the pistons and rotate the pinion clockwise rapidly
. This action will often be used to close a 9U' turn valve in shutdown mode