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. According to 79 statistics, China's pump production reached 1.256 million units. 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, we have designed and manufactured many energy-efficient products in the pump industry, such as IHF, CQB, FSB, UHB and other pump products, which have played a positive role in reducing the 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 selection of pumps, is to comprehensively consider 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, the following aspects must be met: 1. The flow and lift requirements must be met, ie, the point at which the pump runs (the intersection of the device characteristic curve and the pump performance curve) is often maintained in the high-efficiency interval so that both Provincial power is not easy to damage the parts. 2, the selected pump should not only small size, light weight, low cost, but also have good characteristics and high efficiency. 3, with good anti-cavitation performance, this will not only reduce the depth of the excavation of the pump room, but also to pump cavitation, smooth operation, long life. 4, according to the selected pump built pumping station, less project 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. B, discharge pipe and its fittings should consider the maximum pressure that can bear. C, pipe layout should be arranged as straight pipe, pipe fittings to minimize and minimize the length of the pipeline, you must turn when bending the elbow bend radius should be 3 to 5 times the pipe diameter, the angle is greater than 90 ℃. D, the discharge side of the pump must be installed valves (ball valve or globe valve, etc.) and check valve. The valve is used to adjust the operating conditions of the pump. The check valve prevents the pump from reversing when the fluid is flowing backwards and prevents the pump from hitting the water hammer. (When the liquid backflow, will have a huge reverse pressure, so that the pump damage) Second, to determine the flow head 1, the flow of a, if the production process has been given the smallest, normal, maximum flow, should be considered the maximum flow. b, if the production process is only given normal flow, should consider leaving a certain margin. For ns> 100 large low-flow pump with its head, the flow margin taken 5%, ns c, if the basic data only to the weight flow, should be converted into volume flow.
