The sealing performance of instrument pipe valves refers to the ability of each sealing part to prevent media leakage. There are three sealing parts of instrument pipe valves: ① the contact surface between the opening and closing parts and the two sealing surfaces of the valve seat. ② The matching position of the packing with the valve rod and stuffing box. ③ Connection between valve body and valve cover. The leakage of the valve seat sealing surface of the instrument pipe valve is called internal leakage, which is commonly referred to as not being tightly closed, which will affect the function of the instrument pipe valve to cut off the medium. For block valves, internal leakage is not allowed. The leakage of the packing and valve cover of the instrument pipe valve is called external leakage, which means that the medium leaks from the inside of the valve to the outside of the valve. External leakage can cause material loss, pollute the environment, and even cause accidents in severe cases. For flammable, explosive, toxic, or radioactive media, external leakage is not allowed, so instrument pipes and valves must have reliable sealing performance.
