Research on air valve of water supply pipelines

The flow condition of water supply pipelines are affected by terrain, buildings and other external factors, easy to produce the complex phenomenon of hydraulic transient. More seriously, it can cause the pipeline rupture, water supply interruption and equipment damage, resulting in huge economic loss. It is necessary to equip the air valves in actual projects to prevent the gas liquid transient flow. Firstly, this paper illustrated the effect, the type and the principle of air valve in detail. Secondly, combined with the actual projects, the authors analyzed the numerical simulations of water hammer. At last, the authors compared the results of air valve simulation. The results show that by comparison, the two stages closing air valve reduces not only the negative pressure but also the positive pressure than the one stage closing air valve. So the two stages closing air valve for the preventive measure in practical engineering could be effective.