Drainage arrangement for the main steam pipeline on the pipe gallery
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RT: The drain line for the DN350 main steam pipeline on the pipe tray is located behind the U-shaped thermal compensator; it uses flanges instead of having an opening directly in the pipeline for welding. I would like to ask everyone: is it mandatory to do this? For our installation, there is another DN350 pipeline, and for its drainage, a hole is made directly at the bottom of the pipe (via welding) to lead the drainage to the ground.
There are two issues here: whether to use a reduced-diameter tee or weld an opening in the pipe. A tee is a device that is manufactured through processing, and it certainly offers better strength and cleanliness compared to open-hole welding. Flanges can be removed and plugged with blind plates, as opposed to being welded in place
Add a downcomer at the U-shaped bay to conduct water away for hydrophobic treatment.
This is to increase the wall thickness of the branch pipe, and it can also serve as a fluid collection bag. For DN15 pipes, no matter how thick they are, the thickness isn’t that great, and corrosion beneath the insulation layer often becomes quite severe.
There don’t seem to be any special regulations regarding this. The designer might have considered using a fluid collection bag; flanges and flange covers can be used, with a cavity created at the bottom of the flange, or pipe caps can also be welded in place – any of these options will work
This post was last edited by goldliyang on 2017-3-17 09:15. If only a small hole is made in the pipeline, the condensate is pushed across that hole at high speed by the steam, making it difficult to achieve effective water drainage
I didn’t pay attention to this detail. The specifications don’t mention it explicitly
This one seems to be a collection bag with a hydrophobic layer on top
There’s no strict requirement, right? Is it designed this way for easier installation? But why not use welding? Flange connections are prone to leaks
There is no need for a water collection bag; it is connected to a DN40 pipe, with a valve at the base and a manual valve on the ground. Everyone says it works well.