How to choose a water pump?

How to choose a water pump?

The selection of the pump mainly involves data such as working medium, working medium characteristics, head, flow rate, ambient temperature, etc. A suitable pump not only works smoothly, but also has a long service life, and can save the cost to the greatest extent for the user. So, how do we choose the correct type of water pump? as follows:

Steps for pump selection

Select the pump to list the basic data:

1. Characteristics of the medium: medium name, specific gravity, viscosity, corrosiveness, toxicity, etc.

2. The particle diameter and content of the solid contained in the medium.

3. Medium temperature: (°C)

4. The required flow The leakage in the piping system of general industrial Water pump can be ignored in the process flow, but the influence of the process change on the flow must be considered. If the agricultural pump uses open channel water delivery, the leakage and evaporation must also be considered.

5. Pressure: suction pool pressure, drainage pool pressure, pressure drop (head loss) in the piping system.

6. Piping system data (pipe diameter, length, type and number of pipe accessories, geometric elevation from suction pool to pressure pool, etc.).

If necessary, the device characteristic curve should also be drawn. When designing and laying out pipelines, the following items should be paid attention to:

1. Choose the diameter of the pipe reasonably. If the pipe diameter is large, under the same flow rate, the liquid flow velocity is small and the resistance loss is small, but the price is high and the pipe diameter is small, which will lead to a sharp increase in resistance loss and increase the head of the selected pump. With increased belt power, costs and operating expenses are increased. Therefore, it should be considered comprehensively from the perspective of technology and economy.

2. The maximum pressure that the discharge pipe and its joints can withstand should be considered.

3. The pipe layout should be arranged as straight pipe as possible, and the accessories in the pipe should be reduced as much as possible and the length of the pipe should be reduced as much as possible. When turning must be made, the bending radius of the elbow should be 3 to 5 times the diameter of the pipe, and the angle should be greater than 90° as much as possible. ℃.

4. Valves (ball valves or stop valves, etc.) and check valves must be installed on the discharge side of the pump. The valve is used to adjust the operating point of the pump, and the check valve can prevent the pump from reversing when the liquid flows backwards, and prevent the pump from being hit by water hammer. (When the liquid flows backwards, a huge reverse pressure will be generated, which will damage the pump)

Select the Water pump to determine the flow head flow rate determination:

1. If the minimum, normal and maximum flow rates have been given in the production process, the maximum flow rate should be considered.

2. If only the normal flow rate is given in the production process, a certain margin should be considered. For high-flow low-lift pumps with ns>100, the flow margin is 5%, for small-flow high-lift pumps with ns<50, the flow margin is 10%, and for pumps with 50≤ns≤100, the flow margin is also 5% %, for pumps with poor quality and poor operating conditions, the flow margin should be 10%.

3. If the basic data only gives weight flow, it should be converted into volume flow.

Water pump is a general-purpose mechanical equipment with a large number of fields. It is widely used in petroleum, chemical industry, electric power metallurgy, mining, shipbuilding, light industry, agriculture, civil and national defense departments, and occupies an important position in the national economy. According to statistics, my country's pump output reached 5.256 million units. 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 to saving energy.