Development of automatic shut-off valve for leakage of instrument pipe in gas transmission stations

Gas leakage is the largest risk to the safe operation of natural gas transmission stations and valve chambers of long-distance gas pipelines, and it is of high probability for the leakage of instrument pipes. In order to effectively control the leakage risk of the instrument pipes, it is necessary to develop a gauge valve that can automatically shut off when the instrument pipe leaks. Hence, an automatic shut-off valve was developed for the instrument pipes with the closing pressure difference set by the spring structure, so that the valve could be shut down automatically by the pressure difference generated during leakage. The valve is simple in structure and easy to install, consisting of a metal seat, a throttle element, a regulation spring and a needle valve. It can be cut off immediately once a large amount of leakage occurs in the instrument pipe so that the gas supply can be disconnected for the purpose of effectively eliminating the risks caused by leakage. As shown in a series of field application test, the valve is capable of realizing good shutoff effect and stable operation with various performance satisfying the operating requirements, so it can be further promoted and applied.