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Principle and procedure of pump selection

Selection principle

Pumps are a wide range of general-purpose mechanical equipment, which is widely used in petroleum, chemical, power metallurgy, mining, shipbuilding, light industry, agriculture, civil and national defense and other departments, occupies an important position in the national economy. According to statistics in 2002, China's pump output of more than 200 million units, the pump power consumption accounts for more than 21% of the national energy consumption, so vigorously reduce the pump energy consumption, energy conservation with a very significant significance.

At present in the various areas of the national economy, due to unreasonable selection, many of the pump in an unreasonable operating conditions, low efficiency, a lot of energy wasted. Some pumps because the selection is unreasonable, can not be used, or the use of maintenance costs increase, low economic efficiency. This shows that a reasonable pump to save energy is also of great significance.

The so-called rational selection of pumps, is to take into account the pump unit and pump station investment and operating costs and other comprehensive technical and economic indicators, to meet the economic, security, applicable principles. Specifically, there are the following aspects:

Must meet the requirements of the use of flow and head, that is, the pump operating conditions (device characteristics curve and the pump performance curve of the intersection) often maintained in the efficient range of operation, so that both power and not easy to damage the parts.

The selected pump is both small in size, light in weight, costly, and has good characteristics and high efficiency.

Has a good anti-cavitation performance, which can reduce the strength of the construction of the pump platform, and not the pump body cavitation, smooth operation, long life.

According to the selected pump to build pumping stations, project investment is small, low operating costs.

Selection step

First, list the basic data

1, the characteristics of the media: media name, specific gravity, viscosity, corrosion, toxicity and so on.

2, the medium contained in the solid particle diameter, the content of how much.

3, the medium temperature: (℃)

4, the required traffic

General industrial pumps in the process can ignore the leakage in the pipeline system, but must consider the process of changes in the impact of flow. Agricultural pumps If you are using open channel water, you must also consider the leakage and evaporation.

5, pressure: suction tank pressure, drainage tank pressure, pipeline system pressure drop (head loss).

6, pipeline system data (pipe diameter, length, type and number of pipe accessories, suction pool to the pressure of the pressure pool, etc.).

If necessary, the device characteristic curve should also be made.

In the design of the layout of the pipeline, should pay attention to the following matters:

A, reasonable choice of pipe diameter, pipe diameter, in the same flow, the flow rate is small, the resistance loss is small, but the price is high, the pipe diameter is small, will lead to a sharp increase in the loss of the pump, With increased power, cost and operating costs are increased. And therefore should be considered from a technical and economic point of view.

B, the discharge pipe and its pipe joints should be considered the maximum pressure can withstand.

C, the pipe arrangement should be arranged as straight as possible to minimize the pipe accessories and minimize the length of the pipe must be turned when the bend radius of the bend should be 3 to 5 times the diameter of the pipe, the angle is as large as 90 ℃.

D, the pump side must be installed on the valve (ball valve or cut valve, etc.) and check valve. The valve is used to adjust the pump operating point, check valve in the liquid back to prevent the pump reversal, and the pump to avoid water hammer blow. (When the liquid back, it will have a huge reverse pressure, the pump damage)

Second, the flow to determine

A, if the production process has been given the minimum, normal, maximum flow, should be considered the maximum flow.

B, if the production process only gives the normal flow, should consider leaving a certain margin.

For ns> 100 large flow low lift pump, the flow margin is taken, the small flow of ns <50 high lift pump, the flow margin is 10%, 50≤ns≤100 pump, the flow margin also takes 5% For poor quality and poor operating conditions of the pump, the flow margin should take 10%.

C, if the basic data only to the weight flow, should be converted into volume flow.

While most pumps are always tailored to different environments, customer service life and efficiency are growing, and our engineers are experienced experts in design, material selection and monitoring systems. Design, but also often with the user experience exchange, and constantly improve our existing technical level, for the customer's projects and projects to provide the best design.

The company's extensive product range and strong engineering and technical strength, so that we can provide both economical and durable pumps, to ensure that you use our products without worries.