Is it appropriate to weld the valve flange surface in this way?
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Valves for 1.0MPa steam pipelines – with a weld around the entire flange surface; I really don’t understand the designer’s reasoning. There is nothing that others cannot do, only things that one oneself cannot think of. I wonder what the safety officers will think when they see it?
They are all emergency responses during production, expert!
It was handled on-site; it has nothing to do with the designer
How to handle bolt holes? Better change the valve and look for the cause in the bolts and gaskets!
The safety inspectors consider everything to be normal. This is the standard practice for plugging leaks under pressure, and there are no flaws to be found.
Connect a high-pressure injection gun to the connection valves located around it, and use high pressure to inject a heat-resistant sealing material. This material seals off all bolt holes and areas where leakage occurs, creating a new sealing layer; thereafter, turn the screws on the connection valves to close them.
I’ve been at this company for about five years, and despite going through multiple periods of shutdown and restart, this valve is still in the same condition. So I thought it was the designer’s design.
Strictly speaking, this is not a proper method for sealing leaks under pressure... Here, we usually enclose the area first and then apply glue; we don’t weld the flange surfaces directly together.
This is not normal; plugging leaks under pressure is a temporary emergency measure, and the valve gaskets should be replaced promptly after maintenance work stops.
Personal opinion: With 1.0 MPa steam, there’s no problem with welding in this way; compared to box-type structures, less sealant is required and the injection time is shorter； There is a risk of weld crackage, but the risk is acceptable ； Additionally, warning signs should be placed in a prominent position on this valve to prevent burns to people in the event of sudden cracking or leakage.