On determining the head of water pumps
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Now, wastewater needs to be pumped from the ditch into the sewage tank using a sewage pump. There is no height difference between the ditch and the tank, but the pipeline in between has to pass around a building that is 13 meters high. Should this 13-meter height difference be taken into account when calculating the head required for pumping? If these two sewage tanks are connected by pipes to create a circulation system, then would we not need to consider that 13-meter height difference? Thank you all. Also, if the pump operates under economic conditions with a head of no more than 13 meters plus pipe losses, it can exceed 13 meters plus pipe losses when operating at its maximum head. Can it return to economic operating conditions after running for a while? And the pipeline outlet will also be different above and below the liquid surface, right? This post was last edited by genesiskknd on 2009-3-12 10:44]
Which way does your tube go? When going around from the ground, only the height of the ditch and pipe losses need to be considered.
Oh, I didn’t explain myself clearly – the pipe needs to go over that 13-meter-tall building
That is the height of the gutter plus the height of the building, plus the pipe losses (including valves and elbows).
The height of 13 meters, the elbows, and pipe losses should be added
Whether the sewage tanks are connected to form a loop or not, head loss must be taken into account whenever the pipelines need to cross a height of 13 meters.
Thank you all. Also, if the pump operates under economic conditions with a head of no more than 13 meters plus pipe losses, it can exceed 13 meters plus pipe losses when operating at its maximum head. Can it return to economic operating conditions after running for a while? And the pipeline outlet will also be different above and below the liquid surface, right?
13 meters should be added. The head of a water pump refers to the height to which the pump can lift water, usually denoted by the symbol H, with the unit being meters. The head of a centrifugal pump, measured with reference to the centerline of the impeller, consists of two parts. The vertical distance from the centerline of the water pump impeller to the water surface of the water source, that is, the height to which the water pump can draw water up, is called the suction lift, or simply the suction head ； The vertical height from the centerline of the water pump impeller to the water surface of the outlet tank, that is, the height to which the water pump can lift water, is called the water lifting head, or simply the head. In other words, the pump head = suction head + discharge head. It should be noted that the head indicated on the nameplate refers to the head that the pump itself is capable of generating; it does not include the head loss caused by frictional resistance in the pipeline flow. This is something that cannot be ignored when selecting a water pump. Otherwise, water won’t be able to be pumped in.
It’s necessary to add these extra 13 meters in height, because it is the work done by the pump that enables the water to reach this height; in other words, the water is lifted to a height of 13 meters
If it is below the liquid surface, it should be the height difference from the pump outlet to the top of the building + pipe losses； If the highest point of the pipeline does not change, the pump’s operating condition will not change to an economical operating state
Considering the height, I think it’s necessary to refer to the specific parameters of the pump
What’s the need for a water pump? Is a chiller required?