Compressor Anti-Surge Control Valves
Protect against compressor surge and improve stability with Fisher optimized anti-surge valve assemblies.
Surge is defined as the operating point at which centrifugal compressor peak head capability and minimum flow limits are reached. When the plenum pressure behind the compressor is higher than the compressor outlet pressure, the fluid tends to reverse or even flow back in the compressor. As a consequence, the plenum pressure will decrease, inlet pressure will increase and the flow reverses again. As a result, the compressor loses the ability to maintain the peak head when a surge occurs and the entire system becomes unstable. Surging can also cause the compressor to overheat to the point at which the maximum allowable temperature of the unit is exceeded or cause damage to the thrust bearing due to the rotor shifting back and forth from the active to the inactive side.
These valves detect when a process compression stage is approaching to surge and subsequently take action to reverse the movement of the operating point towards the surge line. This decreases the plenum pressure and increases the flow through the compressor, resulting in stable working conditions. It is normally achieved by opening a control valve in a recycle line, returning the discharge gas to the inlet of the compressor via a suction cooler. The resulting increase in compressor inlet volume flow moves the operating point away from surge.
These assemblies are typically made up of a control valve, actuator, digital valve controller, and other accessories, like volume boosters.
A double acting actuator provides optimal performance for anti-surge technology. It provides symmetrical performance in either direction providing optimal stiffness and controllability.
A check valve provides full speed performance when the valve is moving away from the travel stop, capable of reaching the required capacity in less than one second.
Effects of noise and vibration can further damage the compressor and jeopardize efficiency.
Multi-path, multi-stage valve trim is capable of reducing noise levels by as much as 40 dBA. Flow patterns formed by laser cut discs help ensure repeatable noise attenuation and reduced pipe vibration.
Vibration resistant accessories and tubing help eliminate failures in the field
Knowing how your system is behaving is key to predicting when maintenance or intervention is necessary.
With instrumentation that automatically checks the condition of the valve during each partial stroke test, diagnostics such as valve packing friction, air path leakage, valve sticking, actuator spring rate, and bench set can be collected, viewed, and analyzed while the valve remains in service, without impacting the process.
Learn how improving your compressor anti-surge control valve performance can impact the operation of your compressor system. This webinar discusses the Fisher™ ODV Solution for Compressor Anti-Surge and shows a demo of our NPS 12x20 high performance ODV package on a simulated compressor installation in the Emerson Innovation Center in Marshalltown, IA.
The compressor anti-surge control valve is at the center of the anti-surge recycle loop and is integral to achieving reliable compressor operation and designed to prevent compressor surge events. Learn about the main components that make up this field-proven solution.