Pump selection principles and selection steps
The first excerpt uses principles
Pump is a wide range of general mechanical equipment, it is widely used in petroleum, chemical industry, power metallurgy, mining, ship selection, light industry, agriculture, civil and national defense departments, occupies an important position in the national economy. The electric energy consumption of the pump accounts for more than 21% of the national electric energy consumption. Therefore, vigorously reducing the energy consumption of the pump is of great significance for saving energy.
In recent years, our pump industry has designed and developed many high-efficiency and energy-saving products, such as IS, IB, IH, S, D, DG, JC, GMZ, QJ and other types of pump products, which have played a positive role in reducing the energy consumption of pumps. However, at present, in various fields of the national economy, due to unreasonable selection, many pumps are in unreasonable operating conditions, low operating efficiency, and waste a lot of energy. There are pumps due to unreasonable selection, can not be used at all, or the use of maintenance costs increase, low economic efficiency. It can be seen that reasonable pump selection is also of great significance to save energy.
The so-called reasonable pump selection is to comprehensively consider the comprehensive technical and economic indicators such as the investment and operating costs of the pump unit and the pump station, so that it is in line with the principles of economy, safety and applicability. Specifically, there are the following aspects:
(1) Must meet the requirements of the use of flow and head, that is, the operation point of the pump (the intersection of the device characteristic curve and the performance curve of the pump) is often maintained in the high efficiency interval, so that it saves power and is not easy to damage the parts.
(2) The selected pump should be small in size, light in weight, cheap in cost, and have good characteristics and high efficiency.
(3) It has good anti-cavitation performance, which can not only reduce the excavation depth of the pump room, but also prevent the pump from cavitation, stable operation and long life.
(4) Build a pumping station according to the selected pump, with less project investment and low operating costs.
Section 2 Selection steps
1. List basic data:
1, the characteristics of the medium: medium name, specific gravity, viscosity, corrosion, toxicity, etc.
2, the particle diameter and content of the material contained in the medium.
3, medium temperature: (℃)
4, the required flow
General industrial pumps can ignore the amount of leakage in the pipeline system in the process flow, but the impact on the flow rate must be considered when the process changes. If agricultural pumps use open channels to transport water, they must also consider the amount of leakage and evaporation.
5, pressure: suction tank pressure, drainage tank pressure, pressure drop in the pipeline system (head loss).
6. Pipeline system data (pipe diameter, length, type and number of pipe accessories, geometric elevation from suction pool to pressure pool, etc.).
A device characteristic curve should also be made if necessary.
When designing and arranging pipelines, the following matters should be noted:
a, reasonable choice of pipe diameter, pipe diameter is large, under the same flow rate, liquid flow speed is small, resistance loss is small, but the price is high, the pipe diameter is small, will lead to a sharp increase in resistance loss, so that the selected pump head increases, the power increases, the cost and operating costs are increased. Therefore, it should be considered from the perspective of technology and economy. Table 7-1 lists the maximum flow limits for each pipe.
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现代 210-5 挖掘机 进口增压器