Abstract
The author discusses surge conditions in pump-discharge lines caused by the sudden failure of the power supply to the pump driving units in both low-head and high-head plants, particularly the latter. He gives a detailed discussion of surge phenomena in pump discharge lines for (a) the period immediately following the failure of the power supply when the speed of the pump and discharge both decrease, (b) the period during which the reversal of flow continues until maximum discharge is reached in the reverse direction, and (c) the period between the maximum backward flow in the pipe line and the complete stoppage of the backward flow. He shows by graphical representation the conditions occurring during period (b) when the line is equipped with a flap valve and when it is equipped with a surge suppressor. He concludes the paper with a discussion of surge conditions in the discharge lines of large pumping installations as established by test, and compares such conditions with calculated results, pointing out that the design engineer can predetermine such surge conditions and also calculate accurately the effect of various devices employed to limit water hammer in pumping plants.
