Pump working point and adjustment method

The intersection of pump characteristic curve and pipeline characteristic curve intersection point is the working point of the pump. Because the pump is connected with the pipeline, so he must be subject to the constraints of the pipeline. For example, a pump can supply 200 cubic meters of water per hour, but when it is connected to a small-diameter pipe, the amount of water supplied to the pump is restricted by this small-bore pipe and the amount of water supplied is reduced (decreased). Here leads to the resistance loss of the pipeline. The relationship between loss and flow is: hw = AQ ² Where A - pipeline resistance coefficient; Q - flow through the pipeline. It is the same as the previous expression of friction loss along the way. If you draw on the coordinates is a parabola, this parabola is the pipeline characteristic curve. If the pump top water height is Hi, then the pump head formula is: H = Hi + hw That pumping terrain height (or container pressure) is always less than the total pump head, because the pipeline to go to some energy. When the topography height is Hi, the working point's flow is the maximum flow of the pump. The flow will only increase if the height of the pumped terrain (or vessel pressure) is reduced, because of the downward translation of the starting position of the pipe characteristic curve CF. In order to reduce the flow, the pump can be shut off the outlet valve, the use of additional resistance generated by the valve hA, the work point to the left to D. That is, the pipeline resistance coefficient A is increased, so that the pipeline characteristic curve becomes more creep as CE.