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DEARS I HAVE U TUBES FOR HEAT EXC
3

DEARS I HAVE U TUBES FOR HEAT EXC

DEARS I HAVE U TUBES FOR HEAT EXC

(OP)
DEARS
I HAVE U TUBES FOR HEAT EXCHANGER WITH MORE DIFFERENT BEND RADIUS ,ALL MEASURED OVALITY(FLATNESS) FOR ALL KIND OF BEND RADIUS WAS IN TOLERANCE EXCEPT THAT RADIUS= 1 O.D. THE OVALITY MEASURES 14% WHICH IS OUT OF TOLERANCE AS PER TEMA (10%) IS THERE ANY STANDARD FOR U TUBES WITH R=1D AND HOW TO BE ACCEPTABLE FROM ASME (TEMA R>1.5 D)
THANK YOU IN ADVANCE

RE: DEARS I HAVE U TUBES FOR HEAT EXC

If you have bends tighter than the suggested minimum bend radius (1.5d or 2d depending on the specification) then you must accept deviation in the ovality.
Ideally you would have spelled this out in you documents.
Were the tubes ordered to a specification that addresses u-bends and tolerances?
I wouldn't worry about it.
You get little flow through the inner row anyway, I don't see a bit more ovality hurting anything.
I would be more concerned with the wall thinning.
Do you use a Ultrasonic gauge to check this? I would.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: DEARS I HAVE U TUBES FOR HEAT EXC

(OP)
thank you for your concern and all tube thickness already checked and were accepted ,the issue is because the bundle is under ASME inspection AND they need evidences from code and i didnt find any at any codes telling what is the acceptance ratio for R=1D ,thank you

RE: DEARS I HAVE U TUBES FOR HEAT EXC

3
Was there a u-bend tube specification referenced?
In the Stainless Steel world we use A688 which had tolerance limits and clearly states that at tighter bend radius the tolerances do not apply.
Yours are simply outside of the range of the rules and you must therefore accept whatever you get, since you didn't ask for anything specific.
Whoever is inspecting should be criticizing your design for using such tight radius bends and then not giving detailed requirements for them. The bends themselves are fine.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: DEARS I HAVE U TUBES FOR HEAT EXC

Ed nails it again :)

The problem with sloppy work is that the supply FAR EXCEEDS the demand

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