When the large-diameter straight seam submerged arc welded steel pipe hydrostatic testing machine tests the pressure, the first sealing device passes the air in the exhaust pipe of the straight seam steel pipe through both ends of the exhaust valve filling process and the low pressure water filling end, in the 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. The pressure shall be equal to the mechanical equipment used for the metering device, with an accuracy of not less than 1.5 (the maximum allowable error shall not exceed 1.5% of full scale), the range shall be 1.3 to 1.5 times the test pressure, and the dial shall not be less than 150mm in diameter.
