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Hydrostatic test methods and procedures for longitudinal welded pipes

Date:2018-02-23    View:437      Tag:Hydrostatic test methods and procedures for longitudinal welded pipes


Large diameter LSAW steel pipe hydraulic pressure test machine pressure test, the first seal through the test straight seam steel pipe in the exhaust pipe through the exhaust valve filling the two ends of the filling process and low pressure water seal, water After the full low-pressure, high-pressure water jet device through the booster tube to the specified test pressure. After reaching the predetermined test pressure for a predetermined dwell time, if the straight seam steel pipe leaks, the deformation is relieved in the pressure test. Then open the face seal, low-pressure drainage, straight seam steel pipe testing, inspection visual inspection station for suspicious penetration. Record the automatic recording device according to the standard pressure curve of the pressure test process.


Pressure steps:
1. Hydrostatic test pressure Vertical working pressure and test pressure is not less than 0.80mpa; longitudinal working pressure is less than 0.8MPa, hydraulic pressure test pressure 0.8mpa. Pressure test pressure test may not be replaced;
2. Longitudinal unfilled filling junction exposed connection points (including longitudinal and longitudinal attachment joints) and found that leakage should be excluded;
Third, longitudinal pressure test length not exceeding 1000m. A suitable intermediate pipe length shall not exceed the length of the hydrostatic test section of 500 and the longitudinal stress test of the system with different materials shall be carried out separately.
4. When the pressure test tube end should be solid and reliable inspection, pressure test, non-supporting facilities loose off, the valve shall not be used as a seal plate.
5. Pressure should be used with the measuring device of mechanical equipment, accuracy of not less than 1.5 (maximum allowable error of not more than 1.5% of full scale), measuring range should be 1.3 to 1.5 times the test pressure, the dial diameter of not less than 150mm.

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