The key to the installation technology of the pipeline centrifugal pump is to determine the installation height of the centrifugal pump, that is, the suction stroke. This height refers to the vertical distance from the water surface of the water source to the center line of the impeller of the centrifugal pump. It cannot be confused with the allowable vacuum suction height. The allowable suction suction height indicated on the pump product manual or nameplate refers to the vacuum value on the water inlet section of the pump. In addition, it was measured by conducting tests under 1 standard atmosphere and a water temperature of 20°C. It does not take into account the water flow conditions after the suction pipe is matched. The installation height of the water pump should be the remaining part of the value after the vacuum height is allowed to deduct the loss of the suction pipe, and it must overcome the actual terrain water absorption height. The installation height of the water pump cannot exceed the calculated value, otherwise, the centrifugal pump will not be able to pump water. In addition, the size that affects the calculated value is the resistance loss head of the suction pipe. Therefore, it is advisable to use the shortest pipeline layout, and install as few fittings as elbows as much as possible. It is also possible to appropriately configure a larger diameter water pipe to reduce the flow velocity in the pipe.
It should be pointed out that when the elevation and water temperature of the installation site of the pipeline centrifugal pump are different from the test conditions, such as the local altitude is more than 300 meters or the temperature of the pumped water exceeds 20 ℃, the calculated value should be corrected. That is, the atmospheric pressure at different altitudes and the saturated vapor pressure when the water temperature is higher than 20 °C. However, when the water temperature is below 20°C, the saturated steam pressure is negligible.
From the perspective of pipeline installation technology, the suction pipeline requires strict sealing, and no air leakage or water leakage, otherwise it will destroy the vacuum degree at the water inlet of the centrifugal pump, reduce the water output of the centrifugal pump, and even fail to pump water in severe cases. Therefore, it is necessary to do a good job in the interface of the pipeline to ensure the construction quality of the pipeline connection.