This type of actuator is used exclusively for rotary
valves. The edge of the diaphragm is free, and by
attaching a ring, the linear motion of the actuator is
converted to a smooth rotational motion in the
valve stem. Model 280 is a multiple spring type
with four or six small internal springs, while Model
400 is a single spring type with one large spring.
Both models are actuators that feature friction-free
operation, excellent efficiency, and high output.