May I ask how factories detect internal leakage in valves by pressure testing?
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Our company is currently facing quite a few issues with internal leakage in valves, but it’s difficult to determine the cause through standard testing methods. When these valves are taken to a repair shop for pressure testing, it turns out that some of them don’t leak after all. This back-and-forth process is very time-consuming. Since there are regulations within the company that prohibit the purchase of such pressure testing equipment, I’m thinking of creating one myself. The company has an air supply as well as air pumps; it’s just that there are many different flange specifications. I have a rough idea of what it should look like, and I’m wondering if anyone in your companies has built similar pressure testing equipment. I’d like to see what it looks like so that I can learn from it. Thank you everyone.
One can create a simple pressure application device using existing gas sources and air pumps, and then manufacture sealing caps of various sizes corresponding to different flange specifications. Ensure that the sealing cover fits tightly against the flange on the valve, then connect the air source to the air pump via piping to conduct a pressure test on the valve. Pay attention to safety precautions to prevent accidents during the compression process
Generally, factories don’t have pressure testing machines either, so you don’t need to worry about it. For regular valves with low pressure, simply turn the valve upside down, fill the valve chamber with water, and wait for a while to check whether there is any leakage in the other chamber. Matched blind flanges can also be found; threads are tapped on them, water is poured into the valve chamber, the flanges are tightened, a fitting is attached to the tapped holes, and once the instrument air is connected, it is checked to see if there is any leakage on the other side. Finally, you can buy a pressure pump to replace the instrument air with pressure pump air. That’s about it. In cases of extremely high pressure, hydraulic pressure can be used instead; however, it is not recommended to implement this in one’s own factory
The simplest way is to prepare a larger blind plate, drill a hole in its exact center, then weld brackets to the back of the blind plate. A hole is drilled in the middle, and a bracket that can hold the valve is welded there; the rod passes through this bracket and is welded to the bracket used to support the valve. In this way, a simple pressure testing platform is created. All that’s needed is to use the appropriate gasket between the blind flange and the valve during pressure testing.
Construct a square bracket; at the lower end of this bracket, a fixed blind flange is attached. The size of this blind flange corresponds to that of a standard valve opening. A screw rod is installed on the upper crossbeam of the bracket, and another blind flange is connected to the lower end of this screw rod. One side of the outer circle of this second blind flange is open to the internal cavity, allowing a needle valve to be connected there, which facilitates monitoring for any internal leakage in the valve. A hole is drilled in the center of the blind plate below, allowing connection to a gas source for testing