To test the water pressure in the pipe.
1. Pre-test stage: (1) The water pressure in the pipeline will slowly rise to the specified test pressure and stabilize the pressure for 30min. During the period, if the pressure drops, water can be injected to replenish the pressure, and the supplementary pressure shall not be higher than the test pressure; (2) Check whether there is water leakage and damage at the pipe interface and accessories; (3) When there is water leakage and damage, the pressure test should be stopped in time, and the cause should be identified and the corresponding measures should be taken after the pressure test.
2, the main test stage: stop the water injection pressure, stabilize for 15min, after 15min, when the pressure drop does not exceed the allowable pressure drop value, the test pressure will be adjusted to the working pressure and maintain the constant pressure for 30min, the appearance inspection if there is no leakage phenomenon, the water pressure test is qualified. Water pressure test requirements: When conducting water pressure test, the water pressure should rise and fall slowly. When the working pressure is reached, the pressure boost should be suspended to check whether there is water leakage or abnormal phenomenon, and then the pressure is increased to the test pressure. The pressure remains constant during the inspection. The water pressure test should be carried out when the ambient temperature is higher than 5 ° C, otherwise there must be anti-freezing measures, clean water should be selected, industrial water can be used when the requirements are not high, the water temperature should be higher than the surrounding dew point to prevent condensation on the boiler surface, but it should not be too high, generally 20~70 ° C. The test is often used to gradually increase the method, while testing to check the deformation of the equipment, leakage, to the test pressure to maintain pressure for a certain time. There is no water bead and water mist on the metal wall and weld of the pressure element; When reduced to the working pressure, the expansion mouth does not drip; No residual deformation was found after hydraulic test.
Pressure vessel standards have many systems: Chinese standard water pressure test pressure =1.25* design pressure * stress correction factor ASME standard water pressure test pressure =1.3* maximum allowable working pressure * stress correction factor European pressure vessel water pressure test pressure = take the maximum value {1.25* design pressure * stress correction factor; 1.43* Maximum allowable pressure}