Crimping Reformer Furnace Tubes

[pkhenry]

Does anyone have experience in crimping off reform furnace tubes (pigtails) while in operation? Have you had any problems with pigtails cracking at the clamp location? Do you use your own personnel or do you have specialized contractor? What type of equipment and clamps do you use?

We have been crimping in the past but due to cracking of a tube during clamping safety issues have arisen. Our clamps are "home built" and maybe our problem. The pigtail material is Inconel 800H 1-1/2" sch 80 and sch 40.

 

[kstaylor]

Whether your clamps are "home made" or you buy from a specialty contractor you need to check the closed position gap. That is, when the clamp has been completely screwed closed, there should be a gap between the jaws of the clamp. This gap should be equal to or just a hair less than twice the wall thickness of the pigtail pipe you are clamping and should be constant across the length of the gap. If the gap is too small (or non-existant) cracks can occur because you are trying to sever the pipe rather than pinch it. If the gaps are not constant across their length you may wind up with leaks through the pinch or cracks at the corners.

The specialty leak sealing contractors (e.g. Koppl, Team Inc., Furmanite, etc.) can check out your clamps for dimensional tolerances. You can buy pigtail clamps from these guys or independently from the manufacturers (names of the manufacturers escape me right now). One final note, I would NOT try to build my own pigtail pinching clamps unless it was a dire emergency AND leak sealing contractors were days away.

 

[morls]

I was involved in a tube crimp a couple of days ago. The plant sites boilermakers fabricated the crimpping block and the injection block. I was there as a contractor to pump sealant between the crimps to asure there is no flow. We have in the past manufactured out own crimps and blocks. If you would like more information let me know.