Polyethylene valves can be divided into three types according to their uses: standard valves, single relief valves, and double relief valves. At present, the specifications of polyethylene valves for buried gas in China are φ40-φ315. Installation and maintenance of polyethylene valve: Before installation, the valve should be inspected. The inner surface should be clean, and there should be no dirt or dust remaining in the valve, and whether there is falling off or damage. Use a special wrench to open and close the ball valve several times to check whether the opening and closing are good, and do the air tightness test. If the quality is unqualified, installation is not allowed. Set the polyethylene valve to be installed in the open state. During installation, the valve must be perpendicular to the ground and kept on the same axis as the pipeline. The polyethylene ball valve installed at the end of the pipeline needs to be connected to the previous section of the pipe and blocked to facilitate the pipeline. Purge with the next connection. When the pipeline is purged, the polyethylene ball valve installed at the end of the pipeline must be purged in the open state, so as to prevent the spherical surface damage from causing the polyethylene ball valve to be scrapped. The polyethylene valve should also be maintained and inspected during use. Generally, it is required to conduct an opening and closing inspection every 6 months.
