The first section selection principle Pump is a wide range of general-purpose machinery and equipment, it is widely used in petroleum, chemical, electric power metallurgy, mining, ship selection, light industry, agriculture, civil and defense departments in the national economy Occupy an important position. The electricity consumption of the pump accounts for more than 21% of the national electricity consumption. Therefore, reducing the pump energy consumption, the use of energy conservation is of great significance. In recent years, our pump industry has designed and manufactured many energy-efficient products such as IS, IB, IH, S, D, DG, JC, GMZ and QJ pump products, which have played a positive role in reducing pump energy consumption. However, at present, in all fields of the national economy, due to the irrational selection, many pumps are in an unreasonable operating condition, and their operation efficiency is low, thus wasting a lot of energy. Some pump because the selection is not reasonable, can not be used, or the use of maintenance costs increase, low economic benefits. Thus it can be seen that the rational selection of pumps is equally important for energy conservation. The so-called rational election pump, is to take into account the pump unit and pumping station investment and operating costs and other comprehensive technical and economic indicators, to make it in line with economic, security and applicable principles. Specifically, there are the following aspects: (1) Flow and lift requirements must be met, ie the point of operation of the pump (point of intersection of the device characteristic curve with the pump performance curve) is required to be constantly maintained in the high-efficiency interval so that Both save power and not easily damaged parts. (2) The selected pump should not only small size, light weight, low cost, but also have good characteristics and high efficiency. (3) Good anti-cavitation performance, which not only can reduce the depth of excavation of the pump house, but also make the pump cavitation, smooth operation and long service life. (4) According to the selected pump built pumping station, less investment, low operating costs. The second section selection step A, lists the basic data: 1, the characteristics of the media: media name, specific gravity, viscosity, corrosivity, toxicity and so on. 2, contained in the media due to the body particle diameter, content how much. 3, the medium temperature: (℃) 4, the required flow General industrial pumps in the process can be ignored in the pipeline leakage, but must consider the impact of process changes on the flow. Agricultural pumps if the use of open channel water, but also must consider the leakage and evaporation. 5, pressure: suction tank pressure, drainage tank pressure, pressure drop in the piping system (head loss). 6, the piping system data (diameter, length, type and number of pipe fittings, water tank to the pressure tank geometric elevation, etc.). The device characteristics should also be made if necessary. In the design and layout of the pipeline, should pay attention to the following: a, a reasonable choice of pipe diameter, pipe diameter, the same flow, the flow velocity is small, the resistance loss is small, but the price is high, the pipe diameter is small, will lead to a sharp increase in resistance loss Large, so that the selected pump lift, with increased power costs and operating costs have increased. Therefore, it should be considered technically and economically.