However, in all fields of the national economy, due to the unreasonable selection, many pumps are in unreasonable operating conditions, low operating efficiency, and waste a large amount of energy. Other pumps cannot be used at all because the selection type is unreasonable, or the maintenance costs are increased, and the economic benefits are low. It can be seen that reasonable selection of pumps is also of great significance to save energy. The so -called reasonable selection of pumps is to comprehensively consider comprehensive technical and economic indicators such as the investment and operating costs of pump units and pumping stations to meet the principles of economy, security, and applications. Specifically, there are the following aspects: the requirements for using traffic and raising must be met, that is, the operating conditions point of the pump (the intersection of the performance curve of the device characteristic curve and the performance curve of the pump) often maintains it in high -efficiency interval. It is not easy to damage the machine. The selected water pump must not only have a small size, light weight, cheap cost, but also have good characteristics and high efficiency. It has a good anti -vapor erosion performance, so that it can reduce the excavation depth of the pump room without causing the water pump, and run smoothly and long life. According to the selected water pump construction pumping station, the project investment is small and the operating cost is low.