Test Ring Thickness for U-Tube Bundle Exchanger

If you are designing to ASME (Div 1), please refer to Section VIII-1 Appendix 2 and/or UG-34, as required.

ASME Sec VIII Div I Mandatory appendix 2: i have studied it for integral type flanges (Fig 2 sketch 6) design calculation but it is too lenghthy and i could not come up with a solution. However i shall see UG-34 as well.

1 thing i want to know is that what is the difference between channel head flange thicknessand test ring thickness?

How about picture 1 in Figure 2.4?

Exactly what type of heat exchanger do you have (TEMA type)?

It depends on the type of channel head flange you have, most likely integral, and your test ring (if simple) will be a loose type.

I don't know what to say about the length of Appendix 2, other than - it must be done for proper design.

Picture 1 in fig 2.4 is for loose type flanges. Well, the exchanger is TEMA type - BHU. Its channel head flange is integral type.

You mean Test Ring would act as a loose type flange during hydrotesting and it should be designed accordingly, no matter if the channel head flange is integral type. So should i proceed with the loose type flange calculation?

Yes, it is possible/allowed to use a loose flange ring (regardless of channel head flange type).

How about using the existing channel head to bolt/secure the tubesheet? Or is it too inconvenient to rig in/out of place?

Ok, i'll do the loose type flange calculation.

Basically tubesheet is sandwiched between channel and shell integal tpye flanges. Also, tubesheet is not extended for bolting between both flanges. Thats y if channel head is removed and pressure applies to tubesheet incase of hydrotest, a test ring is required to hold the tubesheet.

hi,

Test ring has to be designed considering hydrotest pressure and can be designed as per ASME App. 2. Most specification consider design considering allowable stress as 90% of yield strength.

Now to be very specific, my suggestion for u-tube bundle is just take extended type of tubesheet, i.e. tubesheet is extended for bolting. This will nullify the need of test ring.

Please come back if any doubt.

Yes you r right, test ring is designed for hydrotest pressure.

But the case here is that the exchanger, TEMA type-BHU, has been commisioned at site. so designing of extended tubesheet for bolting is not practical. So, a test ring is needed for the same.