Protection with air-inlet-and-outlet valve from column separation in pumping system

A water supply project consists of 4 level pumping stations in all from bottom up. In the water pumping stations at all levels water supply reaches as far as several kilometers. It is a typical long-distance water supply project. Based on simulated calculation of the water transition process for the water supply project, the authors in this paper choose some measures of preventing the air-inlet (and outlet) valve from the serious vaporization phenomena. The air-inlet (and outlet) valve is a special valve aimed at protecting negative pressure from happening in the process of pump-stopping water-hammer. The valve is usually installed in the raised parts of the pipeline for protection from column separation. By comparing the different effects of the common air-inlet (and outlet) valve and the composite air-inlet (and outlet) valve installed in the pipeline, sensitivity analysis on the diameter ratio of the intake to exhaust part is made.