Core Technical Advantages
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Rapid Response: The 2625 delivers a high volume of air to the actuator only when large input changes occur, significantly increasing the stroking speed for critical control actions.
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Integral Bypass Restriction: A key tuning feature that allows the booster to be bypassed during small, slow signal changes. This ensures that the positioner maintains smooth, stable control without the booster overreacting to minor adjustments.
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Efficiency and Tight Shutoff: Featuring soft seats, the booster provides a tight shutoff when not in active use. This reduces unnecessary instrument air consumption and prevents the saturation of positioner relays.
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Specialized Versions: The series includes the 2625NS, specifically designed for nuclear service with elastomeric components that withstand high temperature and radiation. The 2625 and 2625SST are also available in stainless steel for corrosive environments.
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Safety Certified: Both the 2625 and 2625SST models are certified by exida Consulting LLC for use in Safety Instrumented System (SIS) applications, meeting rigorous functional safety standards.
Technical Core
| Feature | Technical Specification / Detail |
| Primary Function | Increase actuator stroking speed |
| Input/Output Ratio | 1:1 (Pneumatic signal to output pressure) |
| Certification | SIL 3 Capable (exida certified for SIS) |
| Nuclear Service | 2625NS (Radiation and high-temp resistant) |
| Material Options | Aluminum or Stainless Steel (2625SST) |
| Port Sizes | 1/2 NPT, 3/4 NPT, or 1 NPT supply and exhaust |
| Operating Temperature | Standard: -40 to 71°C (-40 to 160°F) |
Applications and Industry Sectors
The 2625 series is typically found on large actuators where the internal volume is too great for a standard positioner to fill quickly.
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Oil and Gas: Rapidly opening or closing large-bore valves in surge protection or emergency shutdown loops.
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Power Generation: Ensuring fast response times for steam turbine bypass and control valves, including nuclear-grade installations.
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Chemical Processing: Handling large-scale throttling valves where process stability depends on quick correction of disturbances.
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Pulp and Paper: Improving the response of heavy-duty dampers and large liquid flow control valves.
Xi’an Yunrui Trading Co., Ltd. Technical Support
Xi’an Yunrui Trading Co., Ltd. is a major supplier of Fisher brand products, providing a comprehensive range of Fisher solutions. We specialize in providing original, high-efficiency Emerson automation solutions to industrial clients. Beyond supplying core hardware like the 2625 Volume Booster, we leverage deep technical expertise to provide professional support and model selection guidance for procurement and engineering projects. By optimizing our supply chain, we provide a distinct pricing advantage, ensuring we offer highly competitive prices while assisting clients in optimizing processes and achieving digital upgrades.
If you are calculating the required stroking time for a large actuator and need to determine if a single or dual 2625 setup is necessary, please contact our technical team for a performance simulation.
