Multi-stage centrifugal pump failure maintenance

Time:

2022-07-28

Multi-stage centrifugal pump failure maintenance First, the phenomenon: centrifugal pump displacement, pressure drop.

First, the phenomenon: centrifugal pump displacement, pressure drop.

The main reason:
① filter clearance is too large, impurities in crude oil clogging pump impeller suction port.
② balance plate and balance disc with improper clearance, shaft and impeller, impeller mouth ring and guide wing anti-friction ring with excessive clearance (caused by different centrifuges);; ③ impeller damage (caused by different centrifuges); ③ impeller damage (caused by different centrifuges).
③ impeller damage (wear damage, corrosion damage, processing quality); ④ oil inlet pipe line leakage; ③ impeller damage (wear damage, corrosion damage, machining quality)
④ oil pipeline leakage caused by supply and transmission relationship disorders.

Treatment method:
① open the low pressure end of the pump, remove the impeller blockage; ② open the centrifugal pump, use the traveller to open the pump.
② open the centrifugal pump, with vernier calipers, internal and external calipers to check the fit gap, the installation of the pump should follow the installation requirements; ③ carefully check the impeller wear surface.
③ carefully check the impeller wear surface; analysis of the causes of damage, the development of the next step in the operation of the programme (the use of pumps under different conditions, not to copy the dogma); ④ check the oil inlet line and the impeller wear surface.
④ check the oil pipeline and related equipment; ④ check the oil pipeline and related equipment; ④ check the oil pipeline and related equipment.

Phenomenon: After starting the pump, the oil delivery is normal, and then the pressure drops slowly.

The main reason:
① filter is too dirty, affecting the flow of oil through; ② oil temperature is too high (the oil flow).
② oil temperature is too high (cavitation) or too low (oil thick); ③ balance tube clogging (oil).
③ Balance pipe blockage (can be checked by hand touch) resulting in high pressure section of the pump head heat affecting the head; ④ incomplete venting, delivery of the head; ④ the pump head is not completely emptied, the pump head is not completely emptied.
④ Incomplete emptying, gas bubbles gradually accumulate in the process of oil transfer to form a gas section, affecting the liquid into the pump; ⑤ After emptying the tank, the pipeline is not completely filled with gas, which affects the liquid into the pump.
After emptying the tank, the pressure change in the pipeline leads to the precipitation of dissolved gas, which affects the oil transfer environment.