D series multistage centrifugal pump is a kind of single suction multistage sectional centrifugal pump, which is used for conveying clear water or other media with physical and chemical properties similar to water. If it is necessary to convey hot water, oil, corrosive liquids or abrasive particles and other media, the purpose can be reached by changing the material of the pump or the material of the over-flow parts, sealing form and increasing the cooling system and so on. Therefore, it is frequently applied as the preferred equipment in the fields of industrial and urban water supply and drainage, garden sprinkler irrigation, fire-fighting pressurization, and long-distance water transmission.