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Lowrider
03-06-2007, 08:44 PM
Can anyone guess which pipe from a bath evaporator has blown while someone pumped out the refrigirant without water running through the tubes?

TXiceman
04-06-2007, 03:57 AM
Since the refrigerant is on the shell and the water was in the tubes, the water expansion could have frozen any number of tubes and you should eddy current test the tubes to check the status. Prior to the eddy current test, pull the heads, pressure the shell side with trace quantities of you refrigerant. Get a bunch of rubber stoppers and plug the tubes on each end. Wait over night and see if you have popped any plugs or stoppers. If none were blown out, pull the plugs one at a time and sniff with a refrigerant detector. If you have any leakers, it will show up.

The eddy current test will show if you have any bulged tubes.

If you bulged the tubes you are in for a trate getting them out. we usually cut a window in the end of the shell so that we can get against the tube sheet and and saw the tubes out with a saws-all. you will have to cut out the bulged section and then pull the tubes. We figure the labor hours at close to double a normal retube. Then you have to reweld the window in the shell and get it recertified per you pressure vessel code.

Ken

Lowrider
05-06-2007, 09:00 PM
If you had taken a look at the picture included you would have seen 149 tubes with a plug in it!

I allready know which one is leak and was only one tube off by guessing before we opened it up!!

Was just wandering if any one else was willing to a gamble!

0.5 bar was enough to blow the plug out!

SOP for us is to drill out the ends, remove the pipe and place a new one. When the new one is in place, with a special tool the pipe is "wedged" in the header. That's not the correct technical term for it, but i can't remember the right one!

US Iceman
05-06-2007, 10:12 PM
...with a special tool the pipe is "wedged" in the header. That's not the correct technical term for it, but i can't remember the right one!


I think the term you are looking for is a "tube roller".

The tube is actually rolled into the tube sheet for a tight seal. My experience with these was; the holes in the tube sheet had grooves machined into them and the roller "rolled" the tube material into these grooves to lock in the tube in place.<!-- / message -->

Lowrider
05-06-2007, 11:40 PM
Right on the money!

I just couldn't think of the correct term!

And yes, there is a groove machined in!