Check valve construction, installation points: 1), installation location, height, direction of import and export must meet the design requirements, pay attention to the direction of flow of the medium should be consistent with the direction of the arrow marked by the valve body, the connection should be firm and tight. 2), the appearance of the valve must be installed before the inspection, the valve nameplate should be consistent with the current national standard "General Valve Flags" GB 12220 requirements. For the working pressure is greater than 1.0 MPa and the main pipe to play the role of cut-off valve, the installation should be carried out before the intensity and tightness test, qualified after the standard use. Strength test, the test pressure of 1.5 times the nominal pressure, the duration of not less than 5min, valve housing, packing should be no leakage as qualified. Tightness test, the test pressure of 1.1 times the nominal pressure; test duration in line with the requirements of GB 50243. 3) Do not subject the check valve to heavy loads in the pipeline. Large aetv One-way valve: Independently supported so that it is not affected by the pressure generated by the piping system.