Please advise: the pump shuts down on its own, often draws air, and no cause can be found

Specifications of the feed pump: Heavy oil pump, capacity of 100 cubic meters per hour, head of 1.6 MPa, power rating of 75 kilowatts; inlet diameter DN200, outlet diameter DN150. Problems: The pump shuts down on its own and often draws in air, with no identifiable cause. First of all, the head value you mentioned is incorrect; the head is usually expressed in meters, and the 1.6 MPa figure you have refers to the outlet pressure. The reasons for the pump to shut down automatically and to run out of fluid frequently might be that the pump shuts down due to overheating. The possible causes include: too low a temperature, thick oil that prevents it from reaching the pump chamber, or oil in the pump chamber that slows down the pump’s rotation, increases its power consumption, leads to overheating, and ultimately causes the pump to shut down automatically. It could also be that the oil in the pipeline through which it is pumped is too viscous, resulting in insufficient power for the pump and causing it to stop due to overheating.

Is it a hot oil pump? If so, is the amount of seal oil used too large?

This process has been in use for over half a year with no problems; the issue only appeared recently. After investigating the cause, there was no excess current in the circuit system, and the temperature of the crude oil was 80 degrees

1. Has there been any change in the density and composition of the medium as determined by analytical testing? ? 2. Check the electrical side: whether the circuit overcurrent protection has been replaced, as it may be too small. 3. Did it occur some time after the equipment maintenance was completed? ? Entrance blocked, filter inspection needed

Automatic shutdown of the pump is not possible; what is referred to as automatic shutdown is basically an overload protection mechanism in action. Heavy oil pumps have high viscosity, and changes in inlet temperature can lead to vacuum conditions in the pump. Low temperatures can result in excessive viscosity, preventing proper flow and thus causing vacuum, while overload can also trigger such a shutdown mechanism.

The pump stopping on its own might be due to an electrical issue; there’s no overcurrent. Is there a variable frequency drive in use? Perhaps the drive has failed. Poor flow is definitely the cause. If we rule out changes in the oil’s properties and lower temperatures, the most likely reason is the presence of foreign objects in the pipelines, which can cause blockages from time to time as the oil flows

The extracted liquid may contain water, and the temperature is high

There are generally several reasons for the pump to stop operating automatically: 1. Thick oil – too high viscosity (low oil temperature) causes the motor to become overloaded； 2. Aging of electrical components. 3. Caused by excessive traffic.

The oil has high viscosity, and the power of the pump motor is too low, resulting in frequent overload trips.

The pump stops operating either due to an increase in the motor’s overload current or because there is a problem with the motor’s circuit controller. Vacuum loss occurs either because the inlet filter is clogged, or because water vaporizes, or as a result of vacuum loss in the pipeline ahead.

1. The pump technical parameters provided initially were incorrect; even heavy oil pumps have specific viscosity ranges. . . 2. The pump’s suction vacuum level is constant. The pump fails to draw in the fluid, mostly because the suction pipe is too thin and creates high resistance. . . 3. The pump outlet is also too small. . . :lol

Pump evacuation may be due to a seal leak, or air intake evacuation； High-temperature vaporization evacuation with water in the medium. The most likely cause of the pump stopping on its own is a fault in the motor.

This post was last edited by zhenghemqx on 2009-5-1 17:52. Reason: 1. The temperature of the raw material used was too low, resulting in high viscosity. 2. The power of the motor used is too low. 3. Electrical issues. 4. The inlet filter is clogged.

You didn’t specify the model of the pump; for heavy oil pumps, gear pumps, cam rotor pumps, and screw pumps are generally used. Pumps of these models are quite sensitive to the viscosity of the oil; could it be that changes in the oil’s viscosity are causing problems with pumping, and such changes lead to motor overload and shutdown? It depends on the situation.

The pump stopping automatically may be due to overheating of the pump; the possible reasons are: too low a temperature or high density, which cause the pump to overheat and thus stop automatically. It’s also possible to bring water. Also, check whether the inlet filter is clogged.