Valve low-pressure sealing test

Test the sealing performance of the valve cover; for some valves, the higher the pressure, the better the sealing quality

The sealing test is used to evaluate the sealing performance of valves

Buy a leak detector for your brother to use for testing; it can detect leaks in just 3 or 5 seconds, right? :P

Test the sealing performance of the valve and determine the leakage level

Low-pressure gas sealing is used to test the sealing performance of valves.

This post was last edited by wangsir85 on 2019-2-28 08:52. Do you mean that high pressure is used to test whether sealing is possible at the highest pressure levels; if sealing is achievable at high pressures, then it can be assumed that sealing should also be possible at lower pressures, so why is it necessary to test at lower pressures as well? 1. In fact, it’s not the case that high pressure ensures sealing while low pressure does not; under high pressure, the valve seat is pushed against the valve core by the pressure, thereby achieving sealing. Hence, the higher the pressure, the better the sealing effect, as it puts more force on the valve seat to press it tightly against the valve core. Of course, it is also necessary to calculate whether the valve seat will be damaged under high pressure. 2. As for low pressure, since the medium pressure is not sufficient to push the valve seat against the valve core, sealing is achieved solely through spring pre-tensioning or the compressional deformation of the valve seat. Therefore, a low-pressure sealing test must be conducted; if leakage occurs at low pressure, it indicates that the seat pre-tightening is insufficient, and it does not press firmly against the valve stem to achieve sealing. 3. In this case, the high-pressure side does not leak, while the low-pressure side does. Of course, the reasons are multifaceted. It’s not the topic of this post. 4. In summary, low-pressure sealing also needs to be tested. If there are any omissions, I hope other experts can offer some guidance.

The expert upstairs explained it in great detail. Everything that exists has a reason for its existence

Then why is airtightness required for low pressure?

If gases can be sealed, then liquids certainly can be sealed as well; however, the reverse is not necessarily true – liquids may be able to be sealed while gases might not. So gas is used at low pressures; it is generally not used at high pressures, as gases are too dangerous under high pressure.