Critical Technical Advantages
-
Integral Mounting and Tubeless Design: The 657R features a cast-in integral mounting pad that eliminates the need for traditional external brackets. When paired with Fisher FIELDVUE™ instruments, the actuator uses an integral air passage to remove the requirement for external tubing and fittings, reducing leak points and parts count.
-
Enhanced Response Sensitivity: By utilizing a shallow casing on the pressure side, internal air volume is minimized. This design ensures faster response times to signal changes, making the 657R ideal for precision throttling applications where process stability is paramount.
-
Optimized Thrust Performance: A molded diaphragm travels within a deep diaphragm casing to minimize effective area change throughout the stroke. This ensures consistent, maximum thrust for the given actuator size and provides highly linear movement across the entire travel range.
-
Rugged Stability and Durability: Constructed with thick-walled cast iron and steel, the 657R provides superior mechanical stability and protection against atmospheric corrosion. This heavy-duty build is specifically engineered to withstand vibration and harsh industrial environments.
-
Versatile Application Compatibility: The 657R supports a wide range of spring rates, travel stops, and manual operators (handwheels). While optimized for modern tubeless setups, it remains compatible with traditional bracket-based mounting kits for legacy pneumatic or electro-pneumatic instruments.
Technical Specifications and Capabilities
| Feature | Details |
| Actuator Type | Direct-Acting (Air-to-Push Down) |
| Mounting System | Integral Pad (eliminates traditional brackets) |
| Pneumatic Interface | Internal Air Passage (Tubeless) or External |
| Construction | Heavy-duty Cast Iron and Steel |
| Performance | Molded diaphragm for maximum thrust-to-size |
| Adaptability | Compatible with 657 and 667 standard accessories |
Primary Applications
-
Oil and Gas Refining: Stable throttling for pressure and flow control in high-pressure hydrocarbon streams.
-
Chemical Processing: Precise handling of volatile media where fast response times improve overall safety.
-
Power Generation: Automated control of steam and water cycles requiring stable pneumatic actuation.
-
General Utility: Reliable modulation for various water, air, and gas distribution systems.
