Generally soft-sealing valves are valves in which the valve plug or valve seat is a non-metallic material (mainly PTFE, rubber, etc.). The soft seal valve has the best sealing effect, but it may leave more or less unclean debris (such as welding slag and iron swarf) in the pipeline installation and system cleaning. When they flow through the regulating valve, it is easy to scratch the soft seat or valve cores, which will increase leakage and seal reliability. Therefore, the choice of soft seal must consider the medium and the strict cleaning of the pipeline before the commissioning of the it.

Metal seal and resurfacing wear-resistant alloys are the best choice for shut-off valves. This method considers the sealing property and also considers the service life and reliability. Although the effect of the zero leakage of the soft seal cannot be met, but it is sufficient to meet the strict and close requirements, and it is durable and more economical.