PSA: Had a tube sheet leak on a job in Gary last week

We were doing a hydro test on a 300-tube exchanger and found a leak at the tube to sheet weld. Turns out the rolling tool was set too light, so the tubes weren't expanding enough into the grooves. Re-rolled the suspect tubes at 40 PSI and it held fine after that. Anyone else run into this issue on older bundles?

2 comments

2 Comments

miles79820d ago

Did your rolling tool get calibrated recently? A buddy of mine had the exact same problem on a 40-year-old bundle last spring, and it turned out the air gauge on his expander was reading 10 PSI too low. He ended up re-rolling about half the tubes and it passed hydro after that.

benb2120d ago

Baker's Hydrostatic in Tulsa did a study on this exact thing back in 2017. They found that about 60% of the time, the rolling tool was fine and the problem was actually the tube sheet holes being out of round from years of thermal cycling. Re-rolling just masks the issue and you might end up with tube wall thinning that fails during the next in-service period. Calibrating the gauge is cheap peace of mind but chasing old bundles with re-rolls is a band-aid, not a fix.