First, the basic working principle of the centrifugal pump

　　The centrifugal pump is designed according to the principle of centrifugal force. The driving motor drives the impeller to rotate by the pump shaft to generate centrifugal force. Under the action of centrifugal force, the liquid is raked along the blade flow path to the impeller outlet, collected by the pump body and sent to the discharge pipe, and the liquid is obtained from the impeller. The energy increases both static pressure and kinetic energy, pushing the liquid to the work site. When the impeller rotates, a negative pressure is formed at the center of the suction port, and a pressure difference is generated between the liquid reservoir and the liquid at the center of the impeller. Under the pressure difference, the liquid is continuously pressed into the suction port of the impeller, and then continuously It is thrown out to achieve continuous fluid transport.

Second, the main components of the centrifugal pump

2.1 Pump body: 

　　The shell of the single-stage pump is volute type, and the inner cavity is a spiral type liquid 　　passage for collecting the liquid pumped out from the impeller and guiding it to the pump outlet to further change the kinetic energy into static pressure. can.

2.2 Impeller: 

　　The impeller is a work component. The impeller is fixed on the shaft by a key, and is driven by the motor to perform energy transfer conversion on the liquid work. According to the structure, it is divided into three types: closed type, open type and semi-open type. The closed impeller is more efficient and the open impeller is less efficient.

2.3 Sealing ring: 

　　It is a sealing device installed between the impeller and the pump casing. By adjusting the 　　gap between the two, the leakage is reduced. If the gap is too large, it will affect the flow of the pump, and the efficiency will decrease. If the gap is too small, the friction between the impeller and the pump casing will cause wear, increase the extra load, and cause the motor to overload and heat. It is preferred that the gap of the seal ring be maintained between 0.2 and 1.3 mm.

2.4 Shaft and bearing:

　　The main part of the pump shaft is used to transfer energy. It rotates at high speed during operation and carries a large torque. The material is generally selected from carbon steel or alloy steel with high strength and is quenched and tempered.

The bearing is a member that supports the pump shaft on the pump shaft, and has two types of rolling bearings and sliding bearings. Common bearing lubrication methods are oil lubrication and grease lubrication.

2.5 Shaft seal: 

　　The seal between the pump shaft and the front and rear end caps is called shaft seal, which 　　mainly prevents the liquid leakage in the pump and the air from entering the pump to achieve the purpose of sealing and preventing the cavitation of the pump caused by the intake air. Shaft seals generally include: skeleton rubber seals, mechanical seals and packing seals.

3. Regular maintenance

    Surface derusting, decontamination and cleaning.

    Inspect the consumables for wear and damage. If the part is worn but still within tolerance, it can continue to be used. If the wear of the part exceeds the tolerance range, it should be considered for use after repair. If it cannot be repaired, it should be replaced with a new one.