1、 Shutdown of screw pump

When the screw pump is stopped, the discharge stop valve should be closed first, and the suction stop valve should be closed after the pump is completely stopped.

Screw pumps are prone to bending due to their long working screw length and poor rigidity, resulting in abnormal operation. The connection of the shaft system must be well aligned; It is best to perform centering work after installation and positioning to avoid deformation caused by pipeline entanglement; When connecting pipelines, they should be independently fixed to minimize interference with the pump. In addition, it is best to use a hanging and fixing method for spare screws during storage to avoid deformation caused by uneven placement.

2、 Starting of screw pump

The screw pump should be started with the suction and discharge stop valve fully open to prevent overload or suction.

Although screw pumps have dry suction capacity, they must be prevented from running dry to avoid scratching the working surface.

If the pump needs to be started when the oil temperature is very low or the viscosity is high, the screw pump should be started with the suction and discharge valves and bypass valves fully open, so that the load at the start of the pump is minimized until the prime mover reaches the rated speed, and then the bypass valve should be gradually closed.

When the bypass valve is opened, the liquid continuously circulates and flows in the pump with throttling, and the more oil is circulated and the longer the circulation time, the more severe the heat generated by the liquid, and even the pump may be damaged due to high-temperature deformation, which must be taken seriously.

3、 Operation of screw pump

The screw pump must operate in the predetermined direction to generate a certain amount of suction and discharge.

When the pump is working, attention should be paid to checking the pressure, temperature, and the operation of the mechanical shaft seal. A slight leakage should be allowed for the shaft seal, and if the leakage does not exceed 20-30 seconds per drop, it is considered normal. If a screw pump produces noise during operation, it is often caused by factors such as low oil temperature, high oil viscosity, air entering the oil, misalignment of the coupling, or excessive wear of the pump.