Pressure release valve for high-pressure gas long-distance pipeline

The utility model discloses a pressure release valve for a high-pressure gas long-distance pipeline. The pressure release valve comprises a tubular shell, a piston in the shell, and a mechanical control structure which is located between the shell and the piston and can control the opening and closing of a pressure relief gas outlet. According to the pressure release valve, through reasonable setting of the pressure of a third spring, pressure in the pipeline is controlled within a certain range, and a purely mechanical valve opening and closing control structure is adopted to achieve quick response; a seal ring is compressed by an interaction force between a rolling wheel and a sealing baffle, and a relatively large pressing force is formed on the seal ring, so that a favorable sealing effect is achieved; during repeated opening and closing, the structure is high in stability and cannot fail to work; the piston adopts a cylindrical structure, and a sliding plate and a slip ring are arranged at the front end and the rear end of the piston for supporting and sliding, so that the structure is relatively symmetrical and therefore relatively stable.