In chemical water supply and drainage systems, the corrosion resistance, sealing performance, and operational efficiency of valves directly determine the stability of the pipeline network operation - chemical media are generally corrosive with acid and alkali, and the pipeline pressure fluctuates greatly. Once leakage occurs, the production shutdown and maintenance costs are extremely high. The sag valve, with its fast assembly, high sealing, and strong corrosion resistance, has become the preferred matching valve for new chemical parks and the renovation of old pipelines. This article will explain its application points from two dimensions: structural characteristics and installation specifications, helping readers avoid common pitfalls in selection and installation.