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31

Jul

what is a centrifugal pump? - Better Technology Co., Ltd.

What is centrifugal pump and how it works?


First, the structure of the centrifugal pump
The centrifugal pump is composed of six parts: impeller, pump body, pump shaft, bearing, sealing ring and stuffing box.

1. The impeller is the core part of the centrifugal pump. Its high speed is high, and the blades on the impeller play a major role. The impeller must pass the static balance test before assembly. The inner and outer surfaces of the impeller are required to be smooth to reduce the frictional loss of water flow.
2. The pump body is also called the pump casing, it is the main body of the pump. And acts as a support and is attached to the bracket on which the bearing is mounted.
3. The function of the pump shaft is to connect the coupling and the motor, and transfer the motor torque to the impeller, so it is the main component that transmits mechanical energy.

4. The bearing is a member that supports the pump shaft, and has two kinds of rolling bearings and sliding bearings. Rolling bearings use butter as a lubricant to refuel properly. Generally 2/3 ~ 3/4 of the volume, too much will heat, too little will be noise and hot! The plain bearing uses a transparent oil as a lubricant and refuels to the oil line. Too much oil will ooze along the pump shaft and float, too few bearings will overheat and burn out! During the pump operation, the temperature of the bearing is at most 85 degrees and generally runs at about 60 degrees. If it is high, it is necessary to find the cause (whether there are impurities, whether the oil is black or not, whether it has water) and deal with it in time!

5. The seal ring is also known as the leak reduction ring. The gap between the impeller inlet and the pump casing is too large, so that the water in the high pressure zone of the pump flows to the low pressure zone through the gap, which affects the water output and reduces the efficiency! Too small gap will cause friction between the impeller and the pump casing. In order to increase the backflow resistance and reduce the internal leakage, and delay the service life of the impeller and the pump casing, a sealing ring is at the inner edge of the pump casing and the outer joint of the impeller, and the sealing gap is preferably kept between 0.25 and 1.10 mm.

6. The stuffing box is mainly composed of packing, water sealing ring, packing tube, packing gland and water sealing tube. The function of the stuffing box is mainly to close the gap between the pump casing and the pump shaft, so that the water in the pump does not flow to the outside and the outside air does not enter the pump. Always keep the vacuum inside the pump! When the pump shaft and the packing friction generate heat, water injection into the water seal to cooling the packing! Keep the pump running properly. Therefore, it is especially important to check the stuffing box during the running inspection of the pump! The packing should be replaced after about 600 hours of operation.

Second, the working principle of the centrifugal pump
The working principle of the centrifugal pump is: the centrifugal pump can send water out due to the centrifugal force. Before the pump is working, the pump body and the inlet pipe must be filled with water to be in a vacuum state. When the impeller rotates rapidly, the blade causes the water to rotate quickly, and the rotating water flies from the impeller under the action of centrifugal force. After the water is thrown, the central portion of the impeller forms a vacuum region. The water of the water source is pressed into the water inlet pipe through the pipe network under the action of atmospheric pressure (or water pressure). This cycle is not stop, which can achieve continuous pumping. Before the centrifugal pump starts, it must be filled with water in the pump casing before it can be started. Otherwise, the pump body will be heated, vibrated, the water output will reduce, and the pump will be damaged (referred to as “cavitation”).