Fisher 657 and 667 Diaphragm Actuators

The Fisher 657 and 667 diaphragm actuators are designed to offer reliable on/off or throttling control valve operation. These spring-return diaphragm actuators adjust the valve plug in response to pneumatic output signals from the controller or valve positioner. The 657 actuator is direct-acting, while the 667 is reverse-acting.

Key Features

• Integral Mounting Pad: Simplifies installation by eliminating traditional mounting brackets and reducing the number of parts needed.

• Internal Air Passage: Eliminates the need for external tubing and fittings when used with Fisher FIELDVUE™ instruments.

• Compatibility: Both actuators are compatible with instruments that use traditional bracket-based mounting kits. The 667 actuator can also be externally tubed for instruments or accessories if required.

• Customization Options: Available with adjustable spring rates, travel stops, and manual operators for nearly any control valve application.

• Optimized Diaphragm Design: The molded diaphragm provides maximum thrust for its size, while its deep casing minimizes area changes throughout travel. A shallow casing on the pressure side reduces volume and response time.

• Rugged Construction: Made from thick-walled cast iron and steel, the actuators offer enhanced stability and corrosion resistance.
  

Specifications

• Actuation Type: Spring-return, Linear

• Certifications: SIL capable, ATEX, CUTR, PED

• Control Type: On/Off, Throttling

• Operating Temperature: Cryogenic, Low Temperature, Standard Temperature, High Temperature

• Power Source: Pneumatic, Manual

• Valve Type: Angle Valve, Globe Valve

Other Configurations: For additional specifications or options, contact your local Emerson business partner or sales office.