Vacuum design of vessel

[GasProcess]

I was calculating the safe thickness of a closed dome ended cylindrical tank subjected to vacuum of 20 inches Mercury and normal atmospheric pressure outside. The length between lines of support is 6000 mm and the vessel dia is 60". Material is SA516 Gr-60. The thickness of the shell is about 10 mm.

I am struck because the thickness of the domes is 5 mm and isolated external corrosion with RWT of 3 mm. Could some one please help me to evaluate the tank.

- Should the calculations be performed with 3 mm as thickness for whole tank? or

- Evaluate the domes separately considering them as sphere with 3 mm thickness while evaluating shell as cylider with 10 mm thickness?

- Also please suggest if a patch plate is welded externally over the corroded area, could the thickness of the dome be considered as 5 mm for the full dome.

Thanks in advance

 

[JoeTank]

The dome and cylinder should be evaluated separately at their respective thicknesses.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[prex]

And if you can pass the check with 3 mm for the heads, then that's all and it's OK (I guess you have good chances for that), otherwise a patch plate could be a solution for a repair, but you should discuss that with your AI.

prex

http://www.xcalcs.com

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