Why should the pump be closed when the centrifugal pump is started?
Therefore to close the outlet valve, the pump during starting output water, the minimum pump power, when the pump reaches the rated speed, slowly open the outlet valve, gradually increase the flow of water, the motor current is gradually increased to the rated current.
On the other hand, the water on the pipe of the inlet pipe of the pump is stationary before the pump is opened, such as the sudden acceleration, and the water behind it can not keep up, which will cause the pressure of the inlet to drop suddenly and vaporize the water, and the centrifugal pump will be evacuated. (because of the centrifugal pump is rotating centrifugal force generated by the pump, leaf water and steam driven (gas) quality is very light, according to F= Ma, the centrifugal force is small, the pump can not be water sent).
Centrifugal pump has an important characteristic: when the pressure (head) is very low, the flow will be great, which can be seen from the characteristics of the pump curve. While the pump power is directly proportional to the flow rate, pump start, no pressure in the pipeline, caused by the pump flow, high power pump, and the pump motor, the rotating part from rest to high-speed operation, need a lot of acceleration, it will cause a great starting current
