TEMA and Tolerance
TEMA and Tolerance
(OP)
Hello,
Can somebody tell me if 9th edition TEMA standards describes tolerances of hole diameters in baffles for shell and tube heat exchangers? Meaning is their a maximum distance specified between tube and tube hole. I'm not an experienced STHE engineer but more experienced with Air Cooled Coolers.
The reason for this question is because I must know what are reasonable tolerances while fabrication? Must these holes be drilled or can these be lassercutted or produced in a different way? Depending on thickness and material, knowing that the surface of the baffle in contact with the tube must be smooth and deburred. Can anybody help me?
Baffles are made out of carbon steel, thickness 8mm, disign included a high amount so we like to produce as efficient as possible.
All our client specified was design according to TEMA.
Please inform me,
Euroweld
Can somebody tell me if 9th edition TEMA standards describes tolerances of hole diameters in baffles for shell and tube heat exchangers? Meaning is their a maximum distance specified between tube and tube hole. I'm not an experienced STHE engineer but more experienced with Air Cooled Coolers.
The reason for this question is because I must know what are reasonable tolerances while fabrication? Must these holes be drilled or can these be lassercutted or produced in a different way? Depending on thickness and material, knowing that the surface of the baffle in contact with the tube must be smooth and deburred. Can anybody help me?
Baffles are made out of carbon steel, thickness 8mm, disign included a high amount so we like to produce as efficient as possible.
All our client specified was design according to TEMA.
Please inform me,
Euroweld





RE: TEMA and Tolerance
Hope it helps,
Cheers,
gr2vessels
RE: TEMA and Tolerance
RE: TEMA and Tolerance
RE: TEMA and Tolerance
RE: TEMA and Tolerance
Regards
r6155
RE: TEMA and Tolerance
Is that mentioned in TEMA?
RE: TEMA and Tolerance
gr2vessels
RE: TEMA and Tolerance
I was planned to buy the TEMA, but above question came to mind directly after the first one.(not good at waiting) I'm hoping to have my own version by the end of next week.
Thanks again
RE: TEMA and Tolerance
Suggest you get some samples done before heading whole hog down that road.
Yeah, drilling may cost more than laser cut, but less than warranty costs.
Regards,
Mike
RE: TEMA and Tolerance
As for piercing, a good Machinist will pierce the hole inside the 'slug' and then spiral the cut out to the actual hole cut. And that cut will be continued past the starting point [overlap] so that any dross from where the spiral met the circular cut is cleaned off.
Get cheap work off a Laser Burning Table, expect +/- 0.020". Not the right machine.
RE: TEMA and Tolerance
I opened a topic in the laser engineering forum for technical solutions. We are seriously trying to find out all possibilities for the future and hoping to get technical feedback there.
Additional I was wondering what the position of TEMA is about this issue. Is this a general exepted manner to produce the baffles? I tried to contact TEMA but they forwarded me to this forum, so knowing I am on the right spot to get the right answers.
RE: TEMA and Tolerance
I doubt TEMA intends to mandate manufacturing processes, after all it is primarily a fabricator association. Meet the requirements, it's up to you what processes you use.
Regards,
Mike
RE: TEMA and Tolerance
One thing that kind of argues against laser cut baffles is that baffles can normally be stack-drilled, laser cutting would have to be done individually I assume. I don't know enough about the economics to be able to guess where break-even might be.
Regards,
Mike
RE: TEMA and Tolerance
I thought maybe TEMA had some guidelines fot applying the laser,I will wait and see what comes out the laser thread.
Thanks
RE: TEMA and Tolerance
If stack drilling, depending on baffle diameter you will need some tie-down bolts within the baffles to resist the chip friction. Drill these holes first, insert the bolts, tighten onto the machine table, then drill the rest of the tube pattern. Typically use a chip-breaker style.