Seeking help with valve internal leakage issue
Thread Content
During the hydrostatic test, the 6.4 MPa flat-plate gate valve met the requirements in terms of strength and sealing performance; so what is the reason for internal leakage of the valve after it was put into use to handle natural gas?
1 Is it sealed? 2 Is it clean? 3 Is it airtight after the pressure test?
Additionally, there is also the issue of medium density.
This post was last edited by guogang87 on 2020-5-13 08:11. A hydrostatic test was indeed carried out on the gas pipeline, including the valves. I suspect that when water was released, impurities remained at the bottom of the valves, resulting in poor sealing
After construction, it is important to purge and clean the pipes of impurities. If impurities get into the sealing groove, it will also damage the seal.
Do not assume that gate valves can provide a tight seal, especially metal-sealed gate valves, as the sealing surfaces are prone to damage.
When testing natural gas valves, a low-pressure sealing test should be conducted using gas; it’s best not to exceed a pressure of one kilogram. For gate valves installed in pipelines, pressure is applied from only one side, and the higher the pressure, the less likely leakage will occur. Do you understand?
Has the pipeline been cleaned and purged? Are there any solid impurities in the medium? ?
The sealing surface of the gate valve may be damaged. After all, no gate valve remains leak-free after being in use for a long time. If high process requirements apply, it is recommended to replace it with a globe valve