Durable Fisher 657 And 667 Pneumatic Diaphragm Actuator For Control Valve

Product Specification

Durable Fisher 657 And 667 Pneumatic Diaphragm Actuator For Control Valve

Fisher 657 and 667 Diaphragm Actuators

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.

Available Configurations

Standard Operating Pressure Range

657 and 667: 0.2 to 1.0 bar (3 to 15 psig) or 0.4 to 2.0 bar (6 to 30 psig)

657-4 and 667-4: 0.2 to 1.9 bar (3 to 27 psig)

667 Size 76: 0.4 to 2.0 bar (6 to 30 psig) or 0 to 3.1 bar (0 to 45 psig)

Output Indication

Stainless steel disk or pointer and graduated scale

Operating Temperature Range

Standard Construction (Nitrile Elastomers): -40 to 82℃ (-40 to 180℉)

Optional Construction (Silicone Diaphragm): -40 to 149℃ (-40 to 300℉)

Maximum Valve Packing Box Temperature: 427℃(800℉) with cast iron yoke

Signal Connections

Sizes 30- 60 and 667 Size 76: 1/4 NPT internal

Sizes 70 and 87: 1/2 NPT internal with 1/4 NPT internal bushing

Size 80

657: 3/4 NPT internal with 1/4 NPT internal bushing

667: 1/2 NPT internal with 1/4 NPT internal bushing

Size 100: 1 NPT internal with 1/4 NPT internal bushing

Construction Materials

Diaphragm Casing

Sizes 30 - 87: Steel

Size 80: Cast iron or steel

Size 100: Cast aluminum 

Diaphragm

Sizes 30 - 87: Nitrile on nylon, Silicone on polyester

Size 100: Nitrile on polyester

Diaphragm Plate

657 Sizes 30- 60, 100: Cast aluminum

657 Sizes 70 - 87: Cast iron or steel

667 Sizes 30 - 60, 100: Cast aluminum or steel

667 Sizes 70 - 87: Cast iron or steel

Actuator Spring: Steel

Spring Adjustor: Steel

Spring Seat: Steel or cast iron

Actuator Stem: Steel

Travel Indicator: Stainless steel

O-Rings: Nitrile

Seal Bushing: Brass

Stem Connector: Zinc-plated steel Yoke

Sizes 30 - 80: Cast iron or steel

Size 100: Steel

Direct Action

All 657 actuators are direct acting. Applying air pressure to the upper diaphragm casing forces the actuator stem downward. When this pressure is reduced, the opposing spring force moves the actuator stem upward. Should the loading pressure fail, the spring forces the stem to the extreme upward position. This provides fail-open action for push-down-to-close valves and fail-closed action for push-down-to-open valves.

657—A direct-acting actuator used on sliding-stem valves. Available in sizes 30 through 100.

657-4—A 657 actuator in sizes 70 and 87, designed with 102 mm (4-inch) travel.

Reverse Action

All 667 actuators are reverse acting. Applying air pressure to the lower diaphragm casing forces the actuator stem upward against the opposing spring force. When this loading pressure is reduced, the spring moves the actuator stem downward. Should the loading pressure fail, the spring forces the stem to the extreme downward position. The actuators

provide fail-closed action for push-down-to-close valves and fail-open action for push-down-to-open valves.

667—A reverse-acting actuator used on sliding-stem valves. Available in sizes 30 through 100 and 76.

667-4—A 667 actuator in sizes 70 and 87, designed with 102 mm (4-inch) travel.