Can a Roots compressor surge?
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Can a Roots compressor surge? How to avoid it?
This post was last edited by CHANGBAISHI on 2022-7-19 06:06. It seems that the surge phenomenon only occurs in centrifugal compressors. Rotary vane compressors are of the positive-displacement type; if the pressure conditions at the inlet and outlet exceed certain limits, it can lead to damage to the equipment. As for how to avoid excessive pressure, the common solutions involve using automatic backflow control for situations where the inlet pressure is too low, while safety valves and backflow valves can be installed to regulate high outlet pressures. There is also motor overcurrent trip control. For reference.
Shutdown interlock at low inlet pressure; no backflow
Surge occurs only in centrifugal compressors. This is because when the inlet flow rate approaches the surge critical value, the gas undergoes rotational stall as a result of changes in the suction angle, which leads to a decrease in the outlet flow rate and pressure. Since the pressure in the outlet piping system is higher than the pressure at the compressor outlet, backflow occurs. As a result of this backflow, the amount of gas is replenished, allowing the compressor to operate normally for a moment; the fluid is then discharged from the compressor outlet, after which the same phenomenon repeats itself, over and over again – this is what is known as surge