Pump selection principles and steps
Selection principle
Pump is a kind of a lot of wide range of general-purpose machinery and equipment, it is widely used in petroleum, chemical, electric power, metallurgy, mining, shipbuilding, light industry, agriculture, civil and national defense departments, occupies an important position in national economy. According to 2002 statistics, the pump output reached more than 200 ten thousand units, of the pump power consumption accounts for more than 21% of the national power consumption, thus reducing pump energy consumption, to save energy use is of great significance.
In various fields of national economy at present, due to the unreasonable type selection, many of the running status of pump in the unreasonable operation efficiency is low, waste a lot of energy. Some pump due to the unreasonable selection, it was impossible to use, or use the maintenance cost increases, the economic benefit is low. Therefore, reasonable choose pump is of great significance to save energy.
So-called reasonable selected pump, is to consider investment and operation cost of pump unit and pumping stations comprehensive technical and economic indexes, such as make it conform to the principle of economy, safety and applicable. In particular, has the following several aspects:
Must meet the requirements of the use of flow and head, which requires the operation condition of the pump point (device characteristic curves with the pump performance curve intersection) often remain within the range of efficient operation, save power and not easy attaint parts.
The choice of the pump are small volume, light weight, cheap, and has good characteristics and higher efficiency.
Has good resistance to cavitation performance, this can not only reduce the pump body platform to build strength, again not cavitation in the pump body, smooth operation, long service life.
According to the selected pump station, pump project less investment, low operating cost.
Selection steps
A basic data, list:
1, the characteristics of the medium: the name of the medium, specific gravity, viscosity, corrosive, toxic, etc.
2, medium contained in the solid particle diameter, how much content.
3, medium temperature (℃)
4, need traffic
General industrial pump can be ignored in the process of pipeline system leakage, but affected by the change of flow must be considered. Agricultural use, if is adopted, open channel water pump must also consider leakage and evaporation.
5, pressure: suction tank pressure, water pressure, the pressure drop of pipeline system (head losses).
6, pipeline system data (diameter, length, kinds and number of pipeline accessories, vacuum pressure to the pool geometry level, etc.).
Should also make the device characteristic curve, if necessary.
Decorate in the design line, should pay attention to the following items:
A, reasonable choose pipe diameter, pipe diameter is big, under the same flow rate, liquid flow velocity is small, small resistance loss, but the price is high, the pipe diameter is small, can lead to resistance losses increase sharply, increase the selected pump lift, installed with power increasing, the cost and operation cost are increased. So from the perspective of technical and economic comprehensive consideration.
B, discharge pipe and pipe joints should be considered are the biggest pressure.
C, pipeline layout should decorate straight pipe as far as possible, try to reduce the attachment and try to narrow the pipe length, pipe must turn, elbow bend radius should be 3 ~ 5 times the diameter of the pipe, as much as possible Angle is greater than 90 ℃.
D, the discharge side of the pump must be installed with the valve (ball valve or valve, etc.) and check valve. Used to adjust the point of pump, valve check valve when the fluid flow reversal can prevent the pump inversion, and makes the pump to avoid water hammer blow. (when the liquid flow back, will produce a great reverse pressure, make the pump damage)
Determine the flow head
Second, the determination of traffic
A, if the production process has been given minimum, normal and maximum flow rate, should be taken into account by the maximum flow.
B, if give only normal flow in the production process, should consider to have a certain margin.
For ns > 100 large capacity low head pump, traffic allowance, for ns < 50 small flow high lift pump, the flow take 10% allowance, 50 ns pump of 100 or less, or less traffic allowance is 5%, the pump of the inferior quality and operating conditions, traffic allowance shall be 10%.
C, if the basic data only to weight rate, should be converted to volume flow.
Although most pump is always according to the use of different environment, but the customer requirements for product service life and efficiency are growing, our engineers in design, material selection, monitoring and control system are experts with rich experience, in addition to the development of new design, also often communicate with user experience, continuously improve the technical level, we have designed for the customer's project and provide the best solution.
Many customers from Shanghai far pump industry manufacturing co., LTD., rich experience of correct selection of benefit, a wide range of products and strong engineering and technical strength, enables us to provide both economic and durable water pump, ensure that you use our products without worries.
