The Fisher™ 667 Spring Diaphragm Actuator is a robust, reverse-acting (air-to-close) pneumatic actuator designed for reliable on/off or throttling control of valves in demanding industrial applications . It responds to a varying pneumatic signal from a controller or positioner, providing precise valve plug positioning for stable process control.
The Fisher™ 667 Spring Diaphragm Actuator is a robust, reverse-acting (air-to-close) pneumatic actuator designed for reliable on/off or throttling control of valves in demanding industrial applications . It responds to a varying pneumatic signal from a controller or positioner, providing precise valve plug positioning for stable process control.
As part of the proven Fisher 657 and 667 series, this actuator is built for a long service life with minimal maintenance . Its key features include a molded diaphragm that operates within a deep head cover, minimizing the area change across the stroke and delivering maximum thrust for its size . The shallow head cover on the pressure signal side reduces the volume that needs to be filled, which minimizes response time for faster control actions .
Constructed with a heavy-walled cast iron and cast steel structure, the 667 actuator offers excellent stability and corrosion resistance . It is versatile enough for use with globe valves and angle valves and can be equipped with various spring rates, travel stops, and manual override options to suit a wide range of control valve applications .
Reverse-Acting Reliability: The 667 model is designed as a reverse-acting (air-to-close) actuator, providing fail-safe open operation upon air supply failure .
High Thrust & Precision: The molded diaphragm provides high thrust for its size and ensures excellent linearity between the applied pressure and travel .
Fast Response: The shallow head cover design on the signal side minimizes cavity volume, leading to a shorter response time .
Rugged Construction: The heavy-walled cast iron and steel construction provides stability and withstands harsh industrial environments .
Integrated Mounting Pad: Eliminates the need for traditional mounting brackets, reducing the number of parts and simplifying installation, especially when paired with Fisher FIELDVUE™ instrumentation .
Low-Temperature Operation: Enhanced specifications ensure reliable performance in temperatures as low as -50°C (-58°F) .
Comprehensive Certifications: Complies with international standards including SIL, ATEX, CUTR, and PED .
| Attribute | Specification |
|---|---|
| Product Series | Fisher™ 667 |
| Actuator Type | Spring-and-Diaphragm, Reverse-Acting (Air-to-Close) |
| Operation | Linear |
| Control Type | On/Off, Throttling (Modulating) |
| Power Source | Pneumatic, Manual Override Available |
| Max. Supply Pressure | Up to 3.1 bar (45 psi) |
| Force Range | 190 N to 160,000 N |
| Stroke Range | 11 mm to 102 mm (0.4 in to 4 in) |
| Environmental Rating | IP66 |
| Certifications | SIL, ATEX, CUTR, PED |
| Body Materials | Cast Iron, Cast Steel |
| Operating Temperature | Standard: -40°C to +82°C (-40°F to +180°F); High-Temp: up to 149°C (300°F) |
The table below summarizes the key specifications for various models within the Fisher 667 series to help you select the correct unit. The information is primarily based on data from .
| Model | Max. Travel (mm) | Spring Range (bar) | Max. Thrust (N) |
|---|---|---|---|
| 667-30 | 19 | 0.2-1.0 / 0.4-2.0 | 3270 |
| 667-34 | 25 | 0.2-1.0 / 0.4-2.0 | 5530 |
| 667-40 | 38 | 0.2-1.0 / 0.4-2.0 | 3680 |
| 667-45 | 51 | 0.2-1.0 / 0.4-2.0 | 8870 |
| 667-46 | 51 | 0.2-1.0 / 0.4-2.0 | 11800 |
| 667-50 | 51 | 0.2-1.0 / 0.4-2.0 | 7010 |
| 667-60 | 51 | 0.2-1.0 / 0.4-2.0 | 8330 |
| 667-70 | 51 | 0.2-1.0 / 0.4-2.0 | 13700 |
Operating Temperature Ranges:
Standard (Nitrile Rubber): -40°C to +82°C (-40°F to +180°F)
Optional (Silicone Diaphragm): -40°C to +149°C (-40°F to +300°F)
Enhanced for Low Temp: Can be used in temperatures as low as -50°C (-58°F)
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