air cooler header

[CadLady]

I would like to learn how to calculate an air cooler header that is made from a solid block instead of plates welded together.
The block is drilled for the plugs and tubes with intersecting holes for the gas flow to the various tubes.

I need to know that the header size will withstand the design pressure.

Can anyone point me in the right direction?

 

[kstaylor]

A quick way to check this would be to treat it as if it were made from welded plates and calculate the required thickness per the ASME VIII-1, Appendix 13 rules. Then compare the thicknesses between the ID of the intersecting holes and the various faces of the header to the calculated required thicknesses. If actual thickness is greater than required you should be OK. Alternately use FEA.

Good luck.

 

[VDK44]

If it is of a hollow rectangular shape with round corners, you can calculate it as per ASME Sec VIII div 1 Appendix 13, where detailed rules are available as also worked out examples. If you provide me with design details I can size the header for you.

sincerely yours,

V.Dwaraka Krishna.
dwarakakrishna@sify.com

 

[rdf]

CadLady & VDK44,

I have seen this done for small units:
Drill tube holes through blocks
Fly-cut "chamber" with overlapping circles so that a Tubeside chamber is formed.

The Triangular Islands that remain are calculated as stays (with an appropriate eff. factor) that connect the "Header Cover" to the "Tubesheet".

This is not often done a Section VIII, Div. 1 stamped unit because you would have to satisfy Par ?, requiring test sample for "hubbed" tubesheet, and not reccomended at all from plate.

I have seen it frequently used to provide a "Non-Code" chamber between "double Tubesheets".