During the pressure test of large diameter LSAW steel pipe hydraulic testing machine, the first sealing device is sealed by both ends of the straight seam steel pipe at the end of the test. The low pressure water injection fills the process air through the exhaust valve in the exhaust pipe. After the water is filled with low pressure, the high pressure water injection device pressurizes the inner pipe through the supercharger until the required test pressure is reached. After reaching the preset residence time of the preset test pressure, if the straight seam steel pipe leaks, the deformation phenomenon will be alleviated in the pressure test. Then open the end seal, low pressure drainage, and inspect the straight seam steel pipe to check whether the visual inspection station is suspicious of penetration. According to the pressure test standard pressure curve automatic recording device for recording.


Pressure steps:
1. The hydrostatic pressure test pressure is not less than 0.80 MPa in the longitudinal direction and 0.8 MPa in the hydrostatic pressure test if the working pressure is less than 0.8 MPa in the longitudinal direction. Pressure test pressure test shall not be replaced.
2. After filling exposed joints (including longitudinal and longitudinal joints) with filling water, there is no longitudinal response and leakage should be eliminated.
3. Longitudinal pressure test length is not more than 1000m. The length of the hydraulic test section is not more than 500 m in the middle section of a fittings. The longitudinal pressure test of different materials in the system should be carried out separately.
4. Valves shall not be used as sealing plates when the end of pressure test tube should be firmly and reliably inspected, pressure test and non-supporting facilities are loosened and cut off.
5. Pressure shall be measured by a mechanical device with measuring device. The accuracy shall not be less than 1.5% (maximum allowable error shall not exceed 1.5% of the full range), the calibration range shall be 1.3 to 1.5 times the test pressure, and the diameter of the dial shall not be less than 150 mm.