Is pressure testing for valves in valve factories done using air pressure?
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Saw a video of a valve bursting during pressure testing
The test for sealing performance is air pressure; it is checked by placing it in water to see if bubbles appear
What is widely used are still hydraulic testing devices, which use compressed air to pressurize water to a certain level.
When the water pressure is high, the valve is fully open, and the sealing surfaces are not under pressure
Water pressure is mostly used to test whether the strength of the valve body meets the requirements; using water pressure provides greater stability and safety； Strength test of valves: (Generally, the following steps are followed) 1. For valves with a nominal pressure of 32 MPa or less, the strength test pressure is 1.5 times the nominal pressure ； 2. Valves with a nominal pressure greater than 32 MPa. The strength test pressure for such valves is 1.3 to 1.4 times the nominal pressure ； 3. The test duration is 5 minutes at the test pressure; the valve is considered qualified if it shows no leakage or seepage and no cracks are present ； 4. During testing, clamp the valve onto the test bench ； Open the valve so that the closing element is in the fully open position, and fill water in from one end of the valve body (for gate valves, globe valves, and straight-through plug valves, introduce it from either end of the passage) ； For check valves introduced from the valve inlet side, after the air in the valve chamber has been completely expelled through the vent holes on the plug at the other end of the valve, the vent holes should be sealed ； Gradually increase the pressure to the test pressure ； If the pressure remains constant throughout the specified pressure duration and no leakage occurs, the strength test is considered successful. But gas pressure testing is mostly used for seal integrity tests!
In the American standard MSS SP-61-2003 for pressure testing of steel valves, specific provisions are made regarding the testing medium
Air pressure experiments are a bit dangerous; compared to water pressure experiments, leaks are not easy to detect, and the leakage takes longer to occur, increasing the risk of accidents
Leak check: no control pressure
The air pressure is achieved through sealed compression. However, the air pressure is generally low. There are few high-pressure pressure tests.