1. Condenser fouling
The scale of water quality on the inner surface of the condenser heat exchange tube (the open circulating cooling water system is easy to scale), which leads to the increase of heat transfer resistance, the reduction of heat exchange effect, and the increase of condensation temperature or the decrease of evaporation temperature. In addition, due to the untreated and poor maintenance of water quality, it also causes the deposit of sand, impurities, algae and other things on the inner surface of the heat exchange tube, resulting in the increase of condensation pressure and the centrifuge surge.
Solution: Remove the dirt on the heat transfer surface and clean the cooling tower.

2. There is air in the refrigeration system
When the centrifugal unit is running, because the evaporator and the low pressure pipeline are in a vacuum state, the connection is very easy to penetrate the air, in addition, the air is a non-condensing gas, the adiabatic index is very high, 1.4, when the air condenses in the upper part of the condenser, causing the condensation pressure and condensation temperature to rise, resulting in centrifuge surge.
Solution: When the centrifuge uses K11 refrigerant, the general liquid temperature exceeds 28 ° C, indicating that there is air in the system. Elimination method: Start the extraction recovery device, discharge the non-condensable gas, generally pump the pressure of the refrigerant R11 to slightly lower than the saturation pressure corresponding to the temperature of the refrigerant, that is, the corresponding pressure below 28 ° C: 117.68KMP below.

3. The cooling tower cooling water circulation is insufficient, the water inlet temperature is too high
Due to the poor cooling effect of the cooling tower, the condensing pressure is too high, and the surge occurs.
Solution: anti-surge regulation. When the energy regulation is greatly reduced, the suction volume is insufficient, that is, the vapor cannot flow evenly into the impeller, resulting in a sudden drop in exhaust pressure, and the compressor is in an unstable working area, and the surge occurs. In order to prevent surge, a part of the compressed steam can be bypassed by the exhaust pipe to the evaporator, which can not only prevent surge. It is also beneficial to the centrifuge start-up: reducing the vapor density and the pressure at start-up can reduce the starting power.

4. Evaporator evaporation temperature is too low
Due to insufficient refrigerant in the system and reduced cooling capacity load, the ball valve is opened too small, resulting in low evaporation pressure and surge.
Solution: Check the reasons why the evaporation pressure is too low, the refrigerant is insufficient to add refrigerant, the cooling capacity is small, and the energy regulation blade is closed.

5. Do not turn off the Angle of the guide vane and reduce the pressure of the centrifuge exhaust port when shutting down
When the centrifuge is shut down, due to the sudden disappearance of pressurization, the high-pressure refrigerant vapor in the volute and condenser is poured back, which is easy to surge.
Solution: When stopping the centrifuge, pay attention to whether the main motor is reversed, and turn off the guide vane Angle as much as possible to reduce the pressure of the centrifuge exhaust port. During the operation of the centrifuge, the condensation pressure and evaporation pressure should be kept stable, so that the refrigerating capacity of the centrifuge is higher than the corresponding refrigerating capacity of the surge point to prevent surge.