Details
Fisher 657 and 667 actuators are designed to provide dependable on/off or throttling operation of control valves.
These spring-opposed diaphragm actuators position the valve plug in the valve in response to varying controller or valve positioner pneumatic output signals. The 657 actuator is direct-acting, while the 667 is reverse-acting.
Features
- The integral mounting pad eliminates the traditional mounting bracket and reduces the number of parts required to mount.
- Incorporates an integral air passage that eliminates the need for external tubing and fittings when paired with a Fisher FIELDVUE™ instrument.
- Both 657 and 667 actuators are compatible with instruments that utilize traditional bracket-based mounting kits. The 667 can be externally tubed for instruments or accessories when required.
- Spring rates, travel stops, and manual operators are available for nearly any control valve application.
- A molded diaphragm travels in a deep diaphragm casing, minimizing area change throughout the travel.
- A shallow casing on the pressure side means reduced volume on that side, thereby minimizing response time.
- The molded diaphragm allows maximum thrust for given diaphragm size.
- Rugged thick-walled cast iron and steel construction provides increased stability and corrosion protection.
