May 20, 2022

The setting principle of the outlet and inlet diameter of the centrifugal pump: Generally, the outlet diameter is selected according to the economic flow rate, and the outlet diameter is determined according to the flow rate. When the pipe diameter is less than 250, it is 1 ~ 1.2m/s, and when the pipe diameter is 250 ~ 1000, it is 1.2 ~ 1.6 m/s. Technically, the maximum speed of water flow should not exceed 2.5 ~ 3.0m/s, and the minimum speed should not be less than 0.6 m/s (to prevent deposition).


The advantages of low inlet flow rate are:

  1. 1.Is conducive to improve the device NPSHA, the pump is not easy to cavitation;
  2. 2.The pipeline scour small, especially containing particles of medium;
  3. 3.Not easy to produce static electricity;
  4. Small pressure drop of inlet filter;
  5. 5.The same section, medium flow uniform, small hydraulic loss.

The disadvantages of low inlet flow rate are:

  1. Under the same flow rate, large pipe diameter and high pipeline cost are required;
  2. 2.For some easy to precipitate medium, the flow rate is too small, easy to cause deposition blockage;
  3. 3.The impeller inlet is large, the diameter of the mouth ring is large and the leakage is large.

The inlet of the pump is generally larger than the outlet diameter. Someone asked Yuhujun backstage, whether the diameter of the import and export pipeline of the centrifugal pump must be increased than the import and export diameter of the pump itself. This problem needs to be analyzed in a specific way.


For most of the pump, the increase of import and export pipeline diameter purpose is to reduce the flow velocity of fluid in the pipe, in order to reduce the pipeline pressure drop, to finally reduce the power consumption of the pump, but increase the diameter at the expense of the increasing pipeline investment costs, so, for the pump discharge for long distance pipeline can consider appropriately increasing the tube diameter, to reduce the pressure drop, But for short distance can not be considered; And for the pump inlet conveying material is liquefied gas, temperature close to the boiling point, suction position is relatively low and easy to cavitation materials, should consider increasing the pump inlet pipe diameter, in order to reduce resistance drop, avoid cavitation pump.

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