Some common problems and solutions of centrifugal pump

Category: Water pump knowledge

2024-05-24

Structure of centrifugal pump

The structure of centrifugal pump can basically be divided into horizontal centrifugal pump and vertical centrifugal pump according to the position of the shaft. At the same time, according to the pressure chamber type and suction mode, it can be divided into volute type and guide vane type. Centrifugal pump is relatively simple, mainly composed of four parts: the prime mover, impeller, pump shell and shaft seal device. The prime mover is the power device of the centrifugal pump, which is generally connected with the pump body through coupling transmission or other transmission methods to provide kinetic energy; the impeller generally has 6-12 backward curved blades, and its main function is to transfer the mechanical energy of the prime mover The pump casing is also called the volute, which is an energy conversion device that collects the liquid thrown by the impeller at the same time; the shaft seal device is the seal between the pump shaft and the pump casing. Its role is to prevent high-pressure liquid from the pump shell along the shaft around the leakage or outside air to inward into the pump shell.

The working principle of centrifugal pump

Take a common water pump as an example. Before starting, the pump shell should be filled with liquid. After starting, the impeller rotates at a high speed under the drive of the motor. When the impeller rotates, the pressure of the water at the inlet of the impeller decreases and is lower than the atmospheric pressure, while the pressure of the water along the radius of the impeller continues to rise, far higher than the atmospheric pressure. In this way, a certain suction force is formed in the inlet pipe. Under the external atmospheric pressure, the low water pushes the inlet valve, enters the pump casing along the inlet pipe, and is thrown into and out of the pipe by the impeller. In this way, water from the lower places can be continuously pumped to the higher places.

Situation 1: The balance is not smooth. Solution: dredge the balance pipe.

Case 2: The material of the balance plate and the balance plate seat does not meet the requirements. Solution: Replace the required material balance plate and balance plate seat.

Case 3: Leakage from other parts. Solution: check the shaft seal and other parts.

Case 4: Poor flushing cooling. Solution: check the flushing cooling circulation pipe.

Case 5: The suction side is suddenly blocked by foreign matter. Solution: stop the centrifugal water pump to deal with foreign matter.

Case 6: Inhale a large amount of gas. Solution: check whether there is a whirlpool suction, submerged depth is too shallow.

Case 7: Increased drag loss. Solution: check pipes, check valves and other obstacles.

Case 8: The casing and impeller wear rings are too worn. Solution: Replace or repair the wear ring and impeller.

Situation 9: The centrifugal water pump is stuck. Solution: check the coupling by hand and disassemble it if necessary to eliminate the fault of dynamic and static parts.

Case 10: When the centrifugal pump is filling, the suction side gas is not discharged. Solution: The centrifugal pump needs to be refilled.

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