Fisher 657NS Diaphragm Actuator
Manufacturer: Fisher — 657/667
Part number: 657NS
Category: Valves
Spring-opposed diaphragm actuator, push-down-to-close (direct acting). Designed for dependable on/off or throttling control valve operation.
Description
Fisher 657 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 is the direct-acting (push-down-to-close) version, complementing the 667 reverse-acting design. The NS designation indicates specific configuration for narrow stem applications. The 657/667 actuator family is one of the most widely used actuator designs in process control, with proven reliability in demanding industrial environments.
Applications
- Control valve actuation
- throttling control
- on-off control
- process automation
- safety instrumented systems
Industries
- Oil & Gas
- Chemical
- Refining
- Power Generation
- Pulp & Paper
- Pharmaceutical
Available on request — pricing is quoted per enquiry. Request a quotation.