The key to the installation technology of the centrifug […]
The key to the installation technology of the centrifugal pump is to determine the installation height of the pump. This height refers to the vertical distance from the water source surface to the center line of the pump impeller. It is not to be confused with the allowable vacuum height. The allowable vacuum height indicated on the pump nameplate or the product manual refers to the vacuum value on the water pump inlet section. It was measured at a standard atmospheric pressure of 1 degree at a water temperature of 20 degrees Celsius. It does not take into account the flow of water after the suction pipe is fitted.
The installation height of the pump should be the value of the remaining part that allows the suction vacuum height to be deducted from the loss of the suction pipe. It must overcome the actual terrain water absorption height. The pump installation height cannot exceed the calculated value, otherwise the pump will not be able to pump water. In addition, the magnitude of the influence calculation value is the resistance loss head of the water suction pipe. Therefore, it is advisable to use the shortest pipe arrangement and to install accessories such as elbows as little as possible. It is also conceivable to properly arrange pipes with larger diameters to reduce the flow rate inside the pipe.
It should be noted that when the elevation and water temperature of the pump installation location are different from the test conditions, such as the local altitude above 300 meters or the water temperature of the pumped water exceeds 20 degrees Celsius, the calculated value should be corrected. That is, the atmospheric pressure at different elevations and the saturated vapor pressure above 20 degrees Celsius. However, when the water temperature is below 20 degrees Celsius, the saturated vapor pressure is negligible.