Pump is a large general-purpose machinery and equipment, it widely application in petroleum, chemical, electric power, metallurgy, mines, ship selection, light industry, agriculture, civil and defense departments, occupies an important position in the national economy. According to 79 years of statistics, China's pump output of up to. Pump power consumption accounts for more than 21% of the national electricity consumption. So it is very important to reduce the energy consumption of the pump and to save energy.
In recent years, we design the pump industry developed a number of energy efficient products, such as pumps QBY, IHF, CQB, PF, FSB, uhB, 2XZ, ZW type products, to reduce the pump energy consumption has played a positive role. But currently in various fields of national economy, because selection is reasonable, many of the pump at a reasonable operating conditions, operating efficiency low waste a lot of energy. Selection of the pump as well as unreasonable, it should not use, or the use and maintenance costs, low economic efficiency. Thus, a reasonable choice of pump is also important to save energy.
So-called reasonable selection of pump, is meant to be a comprehensive consideration of pump and pumping station investment and operating costs, such as comprehensive technical and economic indicators, to meet the economic, security, application of principles. Specifically, there are the following aspects:
Must meet the requirements of the use of flow and head, which requires the pump run time point (device characteristic curve and the pump performance curve of the intersection) to keep running in the high efficiency range, so not only saving power and not easy to damage parts.
The selected pump should not only small size, light weight and low cost, but also has good characteristics and high efficiency.
Has a good anti cavitation performance, so as to reduce the pumping station at the depth of excavation, not to pump cavitation, smooth operation and long life.
Pumping station according to the selected pump, the project investment is low, low operating costs.
Second section pump selection steps
List basic data:
1, the characteristics of the media: media name, specific gravity, viscosity, corrosion, toxicity, etc..
2, the media containing the body of the particle diameter, the amount of content.
3, medium temperature: (c)
4, the required flow
General industrial pump in the process can ignore pipe system leakage, but must consider process changes the influence of the flow. The use of open channel water pump for agriculture if it is, must also consider leakage and evaporation.
5, pressure: suction tank pressure, drainage tank pressure, the pressure drop in the pipeline system (head loss).
6, the pipeline system data (diameter, length, type and number of channels annex, suction pressure tank to the geometric pool elevation).
Device characteristic curves should also be made if required.
In the design of the pipeline, should pay attention to the following matters:
A, reasonable choice of pipe diameter, pipe diameter, under the same flow rate, liquid flow velocity is small, small resistance loss, but the price is high, small diameter pipes, lead to resistance loss increases rapidly, so that the selected to increase the pump head, with a power increase, and operating costs have increased. So it should be considered from the perspective of technology and economy.
B, discharge pipe and pipe fittings shall be considered to be able to withstand the maximum pressure.
C, piping layout should be arranged in a straight as possible and minimize piping attachments and try to reduce the length of the pipeline, must make a turn, the bending radius of the elbow should be 3 to 5 times the pipe diameter, angle as far as possible greater than 90 DEG C.
D, the discharge side of the pump must be fitted with a valve (ball valve or globe valve, etc.) and check valve. The valve is used to adjust the operating point of pump, check valve in the liquid pump to prevent backflow when the reverse, and pumps to avoid water hammer blow. When the liquid flow back, it will have a huge reverse pressure, so that the pump is damaged.
Two, determine the flow head
Determination of flow
A, if the production process has been given the minimum, normal, maximum flow, should be considered by the maximum flow.
B, if the production process is only given normal flow, should be considered to have a certain margin.
For ns>100 high flow low does not lift pump, flow margin 5%, to ns<50 small flow and high lift pump, flow margin take 10%, 50 is less than or equal to NS is less than or equal to 100 pump, flow margin is 5% and the quality poor and bad conditions of pump, flow margin should take 10%.
C, if the basic data only to the weight of the flow, should be converted into volume flow.
