It can also convey liquids, gas mixtures and liquids containing suspended solids. The technical parameters of pump performance include flow, suction lift, head, shaft power, water power, efficiency, etc.; According to different working principles, it can be divided into positive displacement water pumps, vane pumps and other types. Positive displacement pumps use the change in the volume of their working chamber to transfer energy; Vane pumps use the interaction between rotary vanes and water to transfer energy, and there are centrifugal pumps, axial flow pumps and mixed flow pumps.2. Single-stage double-suction centrifugal pumpIt is a single-stage double-suction centrifugal pump that feeds water from both sides of the impeller, because the pump cover and pump body are assembled with horizontal joints, also known as horizontal split centrifugal pump. Compared with single-stage single-suction centrifugal pumps, it has high efficiency, large flow rate and higher head. However, it is large in size and relatively bulky, and is generally used for fixed operations. It is suitable for hills, plateau and medium-sized irrigation areas, and is also suitable for factories, mines, urban water supply and drainage, etc.Single-stage double-suction centrifugal pump has S type, Sh type, SA type, SLA type several models, the difference between S type and Sh type is, from the drive end, S type pump rotates clockwise, Sh type rotates counterclockwise. The SLA type is a vertical single-stage double-suction centrifugal pump.S pump performance range flow rate 160~18000 cubic meters / hour, head 12~125 meters, inlet diameter 150~1400 mm, speed 2950, 1450, 970, 730, 585, 485, 360 rpm.(1) D-type pump performance range flow rate 6.3~720 cubic meters / h, head 16~600 meters, water inlet caliber: 50, 75, 100, 125, 150, 200 mm, of which 50~125 mm pump type is high speed 2950 rpm, 150~200 mm pump type speed is 1480 rpm.(2) Structural type D type multistage centrifugal pump is horizontal multistage (2~12 stages), impeller is single suction, and the pump body is segmented. When the first stage impeller is double suction, it is represented by DS, when there are two speeds specified at the same time, the low speed is indicated by DA, and the multistage centrifugal pump for boiler feed water is represented by DG.