Can flanges be added to both ends of a welded valve to connect pipes?
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For the vent valves used in the medium-pressure steam pipeline materials, the design institute selected welded valves. However, if such valves are damaged, operations must be halted before they can be repaired. Since the valves have already been purchased, I would like to ask whether it is possible to weld flanges at both ends of the valves to facilitate repairs?
The flange may leak. It’s better to think it through carefully
Sure, as long as flaw detection is done after welding
The design institute is concerned about leaks at the flanges itself
It should be possible, because that’s how valve manufacturers do it. Make sure to select flanges made of appropriate grade materials; 100% flaw detection of the welds is required, and check the temperature resistance of the non-metallic components in the valves.
Isn’t it necessary to isolate the valve in the case of a flanged weld as well? The difference is that valves with welded connections are repaired on-site, while valves with flanges are taken back to the repair workshop for maintenance
The issue of leakage still needs to be considered
Adding flanges does increase the risk of leakage, but this doesn’t mean that flanges will definitely cause leaks; as long as flaw detection and installation are carried out according to standards, there will be no problems. It does increase maintenance costs, because over time, due to factors such as pipeline vibration, the flange bolts do loosen, requiring regular inspections and tightening of these bolts.
This concern applies not only to Galfan but also to double valves