The Type 657 and 667 spring-opposed diaphragm actuators position the valve plug in the valve in response to varying controller or valve positioner pneumatic output signals applied to the actuator diaphragm. Zero setting of the actuator is determined by the compression of the actuator spring. Span is set by both the actuator spring rate and the number of springs available. The Type 657 actuator is direct-acting; the Type 667 is reverse-acting. These actuators are designed to provide dependable on-off or throttling operation of automatic control valves.
Best choice in Control Valves and Process Instrumentation. Industry leading customer service and support. Top quality products.
SPC is proud to serve our customers.