Causes of fan surge and treatment methods
Thread Content
Let’s discuss the causes of surge in axial flow main fans and the methods to address it. . .
Phenomenon: a) Fluctuations in the outlet pressure of the main fan； b) Motor current fluctuations ； c) Chattering, at which point the regenerator pressure rises ； d) Increase in inlet temperature ； e) Severe unit vibration, with backflow pulses in the outlet and inlet pipelines as well as in the unit body ； Handling: 1) Once the compressor’s anti-surge protection system detects surge, the unit enters safe operation mode; 2) The anti-surge valve opens fully ； 3) Close the check valve ； 4) Shut down the stator vanes ； 5) The butterfly valve at the flue inlet is closed. 6) If oscillation persists for 20 seconds, the time relay will activate and cause the unit to trip; subsequent actions will be carried out in accordance with the unit tripping procedure. 7) After the unit is operating safely, the static vane control signal must be set to the fully closed position, the inlet disc valve control signal of the exhaust fan must be set to the fully closed position, and the anti-surge valve control signal must be set to the fully open position.
Do not operate in the area to the left of the \"choking point\" on the fan curve; this point is determined by a system curve, depending on the way the fan is installed, among all the operating speeds of the fan.
Reply to 1# 6206856: The simplest way to understand surge is that the medium at the outlet flows back into the compressor
When surge occurs, open the anti-surge valve; if it still cannot be controlled, an emergency shutdown must be performed to prevent accidents
Reply to 2# wyt1234: It shuts down once surge is detected. Is that how your system works? In our system, we first open the anti-surge valve (automatically), and that usually resolves the issue