There are many types of centrifugal pumps. Although the structures of various types of pumps are different, the main components are basically the same. The main components are pump cover, pump body, impeller, stuffing box, pump shaft, shaft coupling, bearing and bracket, etc.
1.Type B pump; one end of the pump is supported by a bearing in the bracket, and the end with the impeller is cantilevered out of the bracket. According to the different positions of the parts of the pump body and the pump cover, it is divided into front-opening type and rear-opening type. The advantage of the rear-opening type is that during maintenance, the bracket and the impeller can be taken out together by loosening the stop nut of the bracket, without removing the pump’s inlet and outlet pipes.
Most of the axial force generated by the impeller of the Type B centrifugal pump is balanced by the balance hole, and the remaining axial force is borne by the bearing. There is a gradually expanding volute flow channel inside the pump body, and an exhaust screw hole is opened at its highest point for filling the pump. A sealing ring is installed at the wear-prone part of the inner wall of the pump cover where the impeller contacts to prevent high-pressure water from leaking back to the water inlet section and affecting the efficiency of the pump. The shaft seal device adopts packing seal, and the pressure water in the pump can be directly sent to the water seal ring through the hole opened on the rear cover to play the role of water seal. This pump can generally be directly connected to the motor through a coupling. Its advantages are simple structure, reliable operation, easy processing and manufacturing, maintenance and repair, strong adaptability, and thus widely used.
2.IS pump; At present, B-type centrifugal pumps have been gradually replaced by IS pumps. This is a single-stage single-suction centrifugal pump with low energy consumption. Compared with the B-type pump, the diameter of the impeller suction port is larger, the suction port and discharge port of the pump housing have been improved, and the pump body is directly supported on the base price. Compared with the B-type pump with the same performance, the IS pump has a smaller power. The pump body and pump cover of the IS pump are rear-opening structures, which have the advantage of convenient maintenance. There is no need to disassemble the pump body, pipelines and motor. You only need to remove the middle connection of the extended coupling to withdraw the rotating parts for maintenance.
IS pumps are suitable for industrial and urban water supply and drainage, and can also be used in agriculture. For conveying clean water or other liquids with physical and chemical properties similar to clean water, the temperature is not higher than 80 degrees.
3.Single-stage double-suction centrifugal pump; this pump is actually equivalent to two B-type pump impellers combined, water enters the impeller from the left and right sides of the impeller, and the flow rate is large. The rotor is supported at both ends, and the pump casing is a volute shape of the horizontal part. The two semi-spiral suction chambers and the pump casing are open-center structures, sharing a suction pipe, and the suction and discharge pipes are both volute-shaped. In order to discharge the gas in the pump when filling the pump, screw holes are opened at the highest points of the pump casing and the suction chamber, and the pump is sealed with bolts after filling. The shaft seal device of the pump mostly adopts packing seal, and a water seal ring is set in the stuffing box. The liquid in the pressure chamber is introduced into it with a thin tube to cool and lubricate the packing. The axial force is self-balanced, and there is no need to set an axial force balancing device. At the same flow rate, the double-suction pump has better anti-cavitation performance than the single-suction pump.