EN 13445 Tube Sheet Design 1

[CobusvanJ]

Hi,

My question is regarding the "uniform thickness for a minimum length adjacent to the tubesheet" requirement specified in 13.4.6.2 and 13.4.6.3 for integral tubesheets.

My calculation ends up stating that I need a minimum channel length adjacent to the tubesheet of 498mm for the channel thickness of 109mm and inside diameter of 1054mm. Does this imply that no nozzle can be located on the channel within that distance from the tubesheet?

 

[CobusvanJ]

I see that in the section for fixed tubesheets on both sides (13.5) there is a clause in 13.5.2.3 and 13.5.2.4 that says to use 9.7.2.1 if there is an opening close to the tubesheets. Any reason why this clause is not in the section for U-tube exchangers as I listed in my original post?

 

[prex]

I would say that the requirement for a uniform thickness over a minimum length is to insure that there will be a collaboration by the shell or channel to the tubesheet in reacting the bending of the latter. Here uniform should mean: 'at least that thickness is present over that length'.
A properly reinforced opening may be in that region without impairing the ability of the shell to resist the bending of the tubesheet, as the reinforcement reconstitutes the thickness.
The reference to 9.7.2.1 is for openings close to a discontinuity: this affects the reinforcement calculation, not the wall thickness, and I assume it should be used whenever that condition is present, even if not referenced by other code parts.

prex

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