Abstract:

ESDU 85044 gives a graphical method of estimating the magnitudes of the surge pressures following power failure to a booster pump that is protected by a one-way valve preventing reverse flow through the pump. The system may also be protected by a bypass which itself includes a one-way valve that closes when flow through the bypass falls to zero. The graphical methods allow the head and flow conditions to be found at the suction and discharge sides of the pump with or without the bypass circuit. The effect of pipe friction may be taken into account. A computer program in Basic is included that also allows the pump run-down characteristics to be modelled and provides results for the pressure changes over the whole line. The use of the information is illustrated in a practical worked example.