In the face of pump selection when many customers and friends is often very difficult, although the effect is the same, but different manufacturers recommended models are their own brands can not go. Correct selection steps and the selection of pump with reference to principles of how much you know? Today is all about selection of pumps should refer to the two principles.
First, everyone should know pump selection principle. Pump which is widely used in petroleum, chemical, metallurgical, mining, power, light industry, agriculture, the ship selection of civilian and defense departments, is a large broad general machinery, in the national economy plays an important role. Selection chosen can greatly reduce the pump energy consumption, energy saving with great significance. In recent years, we pump industry design developed a number of highly efficient energy-saving products, such as ZPD multistage pump, CQB, FSB, UHB and other types of pumps products, to reduce the pump energy consumption has played a positive role. But at present, in the various fields of national economy, because of unreasonable selection, many of the pump at a reasonable operation and no-load operation, low efficiency, waste a lot of energy. Some pumps because of unreasonable selection of pump type selection, can not be used, inappropriate use of repair cost increases, economic benefits is low. Therefore, a reasonable selection of energy saving pump also has important significance. The reasonable selection of pump, is to be integrated into the pump and pumping station of the investment and operation cost, comprehensive technical and economic indexes, so as to meet the safety, economic, applicable principle.
Specifically, the following aspects:
1, must meet the use of flow and water requirements, which requires the operation of the pump working point ( device characteristic curves and pump performance curve of intersection ) are often kept in efficient interval operation, this saves power and is not easily damaged parts.
In 2, the selected pump not only has the advantages of small volume, light weight, low cost, and has good performance and high efficiency.
3, have good anti-cavitation performance, this would both reduce the pumping station excavation depth, not to pump in cavitation, stable operation, long life.
4, pump pumping station built by the selected works, less investment, low operation cost.
In second, followed by selection steps. The correct selection of pump in two steps, one is to list the basic data, the two is to determine the head flow.
A list of basic data:
1, medium contained in the body due to the particle diameter, the number of content.
2: medium, medium characteristic of specific gravity, viscosity, has no corrosion, toxicity, etc..
In 3, the required flow
In 4, the transmission medium temperature: ( c )
General agricultural pumps are used if the water channel, must also consider the leakage and evaporation. Industrial pumps can be neglected in the process piping system of leakage, but must take into account process variations on the impact of traffic. In 5, the pump working pressure: pressure water absorption, the pressure of the drainage pond, piping system pressure drop ( head loss). In 6, the pipeline system data (diameter, length, attachment types and numbers of tubes, suction pressure tank to the geometric pool elevation etc.). If you need to be made device characteristic curves. In the design of piping layout, should pay attention to the following matters: A, reasonable selection of pipe diameter, pipe diameter, at the same flow rate, liquid flow rate is small, small resistance loss, but the price is high, the diameter of the pipe is small, can lead to loss of resistance increase sharply, so that the selected pump lift increase, with a power increase, cost and operation cost increase. Therefore, from technical and economic view. B, exhaust pipe and fittings should be considered to bear the greatest stress. C, discharge pump side must be provided with a valve ( valve or valve ) and check valve. The valve is used to regulate the pump operating point, check valve in the reverse flow of fluid when the pump to prevent reverse, and allows the pump to avoid water hammer blow. ( when the reverse flow of fluid when, can produce tremendous reverse pressure, damage to pumps ) D, piping layout should be arranged in a straight, minimize pipeline accessories and minimize the length of the pipe, must turn, elbow bend radius should be pipeline diameter of 3 ~ 5 times greater than 90, an angle as possible C.
Two, determine the head flow
The determination of the amount
A, if the production process has been given, the normal minimum, maximum flow, maximum flow should be considered.
B, if the underlying data only give weight flow, it shall be converted into volumetric flow.
C, if only given the normal production process flow, consideration should be given to leave some steam voiced allowance.
For NS > 100 the meaning of large flow and low lift pump, flow margin of 5%, NS < 50 small flow high and pump, flow margin of 10%, 50 ns 100 pump, flow margin is 5%, of poor quality and bad operating conditions of the pump, flow margin should be 10%.