Pipeline gas self-closing valve, referred to as self-closing valve, is a device installed on the pipeline of low-pressure gas system. When the gas supply pressure of the pipeline is under-pressure or over-pressure, it can be automatically closed and manually opened without electricity or other external power.

The basic principle of the self-closing valve is to magnetize the permanent magnet material according to the design requirements and make it into a multipolar permanent magnet linkage mechanism with permanent memory, identify the change of gas pressure parameters passing through it, and automatically close the valve and cut off the gas source when it exceeds the safety set value.