Tubesheet with Hub 1

[Aodwan]

Hello All,

We are designing the tube sheet with hub for fixed type shell & tube exchanger per ASME Div I, so we i refer UW-13.3.

Is there any calculation for this design, as UHX only says about tube sheet thickness, and for hub thickness i can use UG-27.

My question if i want to switch from UW-13.3 to UW-31.2 h do i need to show some calculation, if yes what i have to refer.

 

[SnTMan]

Aodwan, "UW-31.2 h"? Do you mean Fig UW-13.2(h)?

Normally, if using a hub it would match the shell cylinder thickness, and UG-27 would apply if mismatching for some reason.

For a corner joint such as UW-13.2 it is only necessary to meet the required weld dimenisons.

Part UHX does not consider, in any way so far as I know, the design of the attachment of the tubesheet to the cylinder(s), this design is covered elsewhere, such as in Part UW. Note however that Part UHX calculations depend on the type of attachment.

Regards,

Mike

 

[Aodwan]

Mike,

Quite clear, thanks.

 

[Aodwan]

Hi,

With reference to this thread, I understood that weld joint for tube sheet to shell shall be determined by UW 13 and UHX says about tube sheet thickness depending on type of tube sheet.

Now what if, if the actual work weld thickness is 1 or 2 mm less than specified in UW, e.g. In my case the ts (sheel thickness) is 28 mm and as per UW 13.2 (h) the a (weld size) shall be same as ts I.e. 28 mm but per actual work it is 26.0 mm.

Now do we re weld and hydro test or is there any calculation to back this.

Please advise.

 

[SnTMan]

Aodwan, don't know if this will help or not, but weld sizing in Part UW is referenced to the corroded thicknesses. This will give a smaller required weld than uncorroded. Also be certain you are correctly accounting for both the "a" and "b" dimensions.

Regards,

Mike

 

[Aodwan]

Thanks Mike it helps, also the minimum thickness of shell required by calculation is only 16.6 but due to some loads we used 28.0, so I suppose if weld size is 26.0 it is much greater than that required.

 

[thunder88]

Hi Aodwan:
Mi comment is not related this thread. I red in another thread that you have one spreadsheet for davits calculation.
How Can I get it?
Regards

Enrique

 

[EnergyMix]

thunder,

What you need to do is Start a New Thread! Then you can referernce the previous thread number by doing thread794-xxxxxx (you'll find the number right under the title). When you don't put any space between the word thread and the first number, as in my example, it will automatically link to the thread.

Then if Aodwan is in a generous mood, he'll provide a link to his spreadsheet. But there's no guarantee, as he probably put a lot of time and effort into developing it.

And maybe it's because my background is nuclear and I have to meet this horrible thing called "quality assurance requirements" -- but how do you assure the provenance of a spreadsheet you get over the Internet?

Want to know the do's and don'ts of Eng-Tips? Read FAQ731-376.
English not your native language? Looking for some help in getting your question across to others or understanding their answers? Go to forum1529.

 

[rmw]

EM,

Haven't you heard that the ISO in, for example, ISO 900X means "Internet Sourced Only"?

rmw

 

[EnergyMix]

rmw

Haven't you heard that the ISO in, for example, ISO 900X means "Internet Sourced Only"?

Sometimes it seems that way.

Want to know the do's and don'ts of Eng-Tips? Read FAQ731-376.
English not your native language? Looking for some help in getting your question across to others or understanding their answers? Go to forum1529.

 

[chicopee]

Tube sheets with hubs were very common in Bigelow fire tube boilers.
Then the tube sheets would be fillet weld to the inside of the shells at the front edge of the hubs