Key Technical Advantages for Process Control
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Integral Mounting and Air Passage: The 657R features a built-in mounting pad that eliminates the need for traditional external brackets, reducing the total part count for valve assembly. When paired with Fisher FIELDVUE™ instruments, an integral air passage allows for a tubeless connection, removing external fittings and tubing that are susceptible to leaks and mechanical damage.
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Enhanced Response Time: The actuator is designed with a shallow casing on the pressure side, which minimizes internal air volume. This specialized architecture ensures a faster response to pneumatic signal changes, allowing for tighter control in sensitive process loops.
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Optimized Diaphragm Performance: A molded diaphragm moves within a deep diaphragm casing, ensuring that the effective area remains consistent throughout the entire stroke. This results in highly linear movement and allows the actuator to deliver maximum thrust relative to its size.
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Rugged Industrial Construction: Built with thick-walled cast iron and steel, the 657R provides exceptional mechanical stability and corrosion protection. This heavy-duty construction is essential for long-term reliability in high-vibration environments such as chemical plants, refineries, and power stations.
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Versatile Configuration: Fisher offers a wide range of spring rates, travel stops, and manual operators (handwheels) for the 657R. This flexibility ensures the actuator can be tailored to meet the specific requirements of nearly any control valve application.
Technical Specifications and Capabilities
| Feature | Details |
| Actuation Action | Direct-Acting (Air-to-Push Down) |
| Mounting Design | Integral Pad (for simplified installation) |
| Air Connection | Tubeless (with FIELDVUE) or Traditional External |
| Construction Material | Cast Iron and Steel |
| Performance | High thrust-to-size ratio with molded diaphragm |
| Compatibility | Supports 657 and 667 standard accessories |
Primary Applications
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Hydrocarbon Processing: Stable throttling for pressure and flow control in oil and gas refineries.
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Chemical Production: Precise management of volatile or corrosive media where fast response is critical for safety.
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Power Generation: Control of steam and water cycles requiring high-thrust pneumatic actuation.
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General Manufacturing: Reliable on/off and modulation for utility and process lines.
