Full Ti heat exchanger type BEM - Welding final closing seam shell-tubesheet

[flaka]

Hi,

We have a full titanium exchanger type BEM, with size ø1100mm and length 4500mm which we need to build.

Our question: What is common practice for the backing gas for the final closing joint (shell-tubesheet) when all tubes are already installed?

[li]Filling the exchanger completly with Ar (=large amount), and hope we could reach 20ppm[/li]
[li]Try to close the area around the tubes with dissolvable paper and install purging tube inside, but outer tube limit is large...[/li]
[li]Put it under vacuum and then filling with Ar[/li]
[li]other idea's?[/li]

Thanks for your input

 

[r6155]

I assume you has a approved welding procedure, then try with a mock-up.

Regards
r6155

 

[EdStainless]

It isn't that large, Ar purge the entire inside.
A standard portable cylinder of liquid argon is 160l, or 4200 SCF.
Without anything in side it your shell is only 150 cu ft.

My guess is that you will be held responsible for the color on the ID of this weld, so purge it well.

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P.E. Metallurgy, Plymouth Tube