What Causes Centrifuge Surge

What Causes Centrifuge Surge

A centrifuge is a machine that uses centrifugal force to accelerate the separation of different materials that need to be separated. Refrigerated centrifuges are divided into low-speed, high-speed refrigerated centrifuges, and ultra-fast analysis, preparation dual-purpose refrigerated centrifuges and other models.

Centrifuge surge is the killer of centrifuges. High-speed refrigerated centrifuges and ultra-high-speed refrigerated centrifuges have a relatively high probability of surge. In severe cases, centrifuge rotors and other accessories will be damaged. Here we’ll analyze the reasons for centrifuge surge:

Centrifuge surge causes:

1. Condenser fouling: the inner surface of the condenser heat exchange tube is fouled (the open circulation cooling water system is most prone to fouling), which leads to an increase in heat transfer resistance and a decrease in heat exchange effect, making the condensing temperature increases or the evaporation temperature decreases. In addition, due to the untreated water quality and poor maintenance, sand, impurities, algae and other substances are deposited on the inner surface of the heat exchange tube, resulting in an increase in the condensing pressure and causing the centrifuge to surge.

2. There is air in the refrigeration system: when the centrifugal unit is running, since the evaporator and the low-pressure pipeline are in a vacuum state, it is very easy for air to penetrate into the connection. In addition, air is a non-condensable gas with a high adiabatic index of 1.4.  When the air condenses on the upper part of the condenser, the condensing pressure and condensing temperature increase, which leads to the surge of the centrifuge.

3. The circulation of cooling water in the cooling tower is insufficient, and the inlet water temperature is too high. Surge occurs due to the high condensing pressure caused by the poor cooling effect of the cooling tower.

4. The evaporation temperature of the evaporator is too low: due to the insufficient refrigerant in the system, the reduction of the cooling capacity load, and the small opening of the ball valve, the evaporation pressure is too low and the surge occurs.

5. Do not close the guide vane angle and reduce the centrifuge exhaust port pressure when shutting down. When the centrifuge is shut down, the high pressure refrigerant vapor in the volute and condenser flows backward due to the sudden disappearance of the boost pressure, which is prone to surge.

6. The impeller rubs the casing and the bearing is unbalanced.