Whether it is using newvalve, Or use the repaired valve, pressure test must be done before installation.
Valve pressure test refers to the strength test of the valve body.Leak test refers to the tightness test of the sealing surface. These two tests are the inspection of the main performance of the valve.
The test medium is generally clean water at room temperature, and kerosene can be used for important valves.In the constant pressure test of the safety valve, nitrogen can be used as a more stable gas or steam or air can be used instead.For diaphragm valves, use air for the test.
The nominal pressure ranges from 0.4Mpa-32Mpa, these commonly used pressure valves,valveThe strength test pressure is 1.5 times of its nominal pressure.
The valve sealing test pressure is equal to 1.1 times the nominal pressure.
The pressure test of the valve is carried out on the test bench.The structure of the valve test bench, there is a compression part on the test bench, and a pipeline connected with the pressure test pump under the test bench.After pressing the valve tightly, the pressure test pump works. From the pressure gauge of the pressure test pump, the number of the pressure that the valve bears can be read out.When the valve is pressure-tested and filled with water, the air in the valve must be drained.The pressure plate on the upper part of the test bench has vent holes, which can be opened and closed with small valves.The sign of air exhaustion is that all that comes out of the vent is water.
After closing the vent, the pressure starts to increase.The boost process should be slow, not sharp.After reaching the specified pressure, keep it for 3 minutes, and the pressure will not change as qualified.
1. Open the valve passage, fill the valve cavity with water (or kerosene), and increase the pressure to the pressure required by the strength test, and check the valve body, valve cover, gasket, and packing for leakage.
2. Close the valve circuit, pressurize to the nominal pressure on one side of the valve, and check for leakage from the other side.
3. Turn the valve upside down and test the opposite side.