Water hammer protection effect of vacuum break valve on siphon cut-off pipeline
Bentley Hammer software was used to analyze the hydraulic transition process for the water hammer protection of siphon cut-off structure pipeline,and a combined protection scheme of hydraulic control butterfly valve and vacuum breaking valve after pump was proposed.Combined with the pipeline pressure control standard,the protective effect of vacuum breaking valve on water hammer at the siphon structure was analyzed and compared under the condition of pump accident shutdown.At the same time,the protective effect of vacuum damage valve on water hammer under different inlet diame-ters and different setting values was discussed and analyzed.The calculation results show that the addi-tion of a vacuum breaking valve greatly improves the negative pressure of water hammer at siphon,and the minimum negative pressure of water hammer is-3.69 m.The larger the diameter of the vacuum damage valve is,the better the protection effect,and the optimal diameter is set to 1/3 of the pipe diameter.The larger the setting value of the vacuum breaking valve is,the weaker the effect of water hammer protection is.When the setting value is set to-3.80 m,the negative pressure of the pipeline water hammer is the smallest,and the valve does not operate when the setting value is less than the minimum pressure of the pipeline.The analysis results provide a certain reference for the selection of vacuum breaking valve,which is of great significance for the water hammer protection of siphon cut-off structure water conveyance projects.