Flange valve converted to welded valve
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The flange valves in the steam system used to leak frequently; even after installing gaskets, leaks would occur whenever the temperature or pressure changed. Now welded valves are being used, so pipeline stress and similar factors shouldn’t cause any issues
It depends on the size of the pipe and the specific operating conditions; if the size is large, a stress analysis is required
What to do if there is internal leakage in the valve? We have internal leakage here; the valve body gets worn through, so it needs to be cut out and replaced.
It depends on comprehensive factors such as stress analysis in pipeline design and on-site assembly welding. Previously, when connecting pipes to equipment, after the inspection and acceptance process was completed but before pre-commissioning, the manufacturer would remove the flanges used for connection in order to check whether they were aligned with the equipment; if not, adjustments would be made. At that time, there was stress on the pipe ends resulting from the alignment work carried out on site.
A factory like yours should have a design department; ask them to do the calculations. You can also ask the unit responsible for the modifications to carry out the calculations. Remember, drawings are also required for any changes to the pipes
The pipeline valves aren’t installed properly, right? Why is there always leakage?
We just changed it from butt welding to flange connection; why are you going back to the previous setup?
Why do you want to switch back to flanged valves?