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separating a very reluctant flanged joint

Posted: Fri Mar 27, 2020 6:10 pm
by hedleypiper
Help;
I have to inspect the inside of my boiler. It is a central vertical steel drum, 6" diameter, with a " top hat " steam chest. There are multiple copper tubes into/out from the steel drum (32 ?). The safety valves, steam take off, water inflow pipe and and the blowdown pipe form a cross. They are welded into the "top hat". The "top hat" has an economiser tube completely shrouding it and the join between the top and bottom parts. The two parts are joined by a wide flanged joint with 12 5/8th studs in the lower flange. The plate of the flanges is about 5/8th. There is a fibre gasket, probably asbestos, between the two.

I can not separate the bug....s. One can not get to the side of the gasket because it is covered by the economiser tubes. I have tried gentle heat, Plumbers blowtorch, propane, I have tapped firmly with a heavy hammer and I have run out of ideas. I have considered hitting harder with a sledge hammer with the boiler on an angle, but it is always resting on its copper tubes. I considered drilling and tapping the upper flange and putting in a couple of bolts to separate the two.

Any advice welcome.Hedley Piper

Re: separating a very reluctant flanged joint

Posted: Fri Mar 27, 2020 10:08 pm
by Mike Rometer
Without a picture or two it's difficult to be sure, but jacking bolts would probably do it. A large block of hardwood and a big hammer might also manage.

Re: separating a very reluctant flanged joint

Posted: Fri Mar 27, 2020 11:22 pm
by Lopez Mike
Is there a way to re-assemble it without those 5/8" nuts and arrange for a deliberately "failed" hydro test?

Re: separating a very reluctant flanged joint

Posted: Sat Mar 28, 2020 10:04 am
by Mike Rometer
Lopez Mike wrote:
Fri Mar 27, 2020 11:22 pm
Is there a way to re-assemble it without those 5/8" nuts and arrange for a deliberately "failed" hydro test?
I think the problem with that could be that the gasket would give in the weakest place, and still leave the rest stuck fast. Any port in a storm though.

Re: separating a very reluctant flanged joint

Posted: Sat Mar 28, 2020 3:10 pm
by Lopez Mike
It might be enough just to get it started.

Another brain storm would be to tap one of the flanges finishing up with a bottoming tap (3/4" fine?) and force them apart with some cap screws.

There is the old standby uncontrolled method of filling the whole thing up with water and freezing it but I'm pretty sure the wrong things would be forced apart?

With modern electric welding one can pretty much repair any damage you might do getting things apart.

Re: separating a very reluctant flanged joint

Posted: Sun Mar 29, 2020 2:13 am
by DetroiTug
Heat one of the components with a torch to right below red hot, it will expand and break the seal. The copper tubes attached can handle a few thousand degrees. Also, if the boiler is built with the correct malleable material, a good rap with a hammer shouldn't Hurt anything.

Re: separating a very reluctant flanged joint

Posted: Sun Mar 29, 2020 5:44 pm
by steamdon-jr
Mike Rometer wrote:
Sat Mar 28, 2020 10:04 am
Lopez Mike wrote:
Fri Mar 27, 2020 11:22 pm
Is there a way to re-assemble it without those 5/8" nuts and arrange for a deliberately "failed" hydro test?
I think the problem with that could be that the gasket would give in the weakest place, and still leave the rest stuck fast. Any port in a storm though.
I think that is a rather good idea. maybe leave the nuts on though but very loose.....I think if it breaks the gasket you are one step much closer to free

Re: separating a very reluctant flanged joint

Posted: Sun Mar 29, 2020 5:44 pm
by steamdon-jr
Mike Rometer wrote:
Sat Mar 28, 2020 10:04 am
Lopez Mike wrote:
Fri Mar 27, 2020 11:22 pm
Is there a way to re-assemble it without those 5/8" nuts and arrange for a deliberately "failed" hydro test?
I think the problem with that could be that the gasket would give in the weakest place, and still leave the rest stuck fast. Any port in a storm though.
I think that is a rather good idea. maybe leave the nuts on though but very loose.....I think if it breaks the gasket you are one step much closer to free

Re: separating a very reluctant flanged joint

Posted: Thu Apr 16, 2020 12:47 pm
by hedleypiper
Eventually supported the boiler from above the flange joint, the weight of most of the boiler hanging. Replaced all the nuts to exactly the stud height and using a lead hammer and a lead sheet hit the nuts/studs hard in rotation. Did not damage the studs. Now resealed with a copper gasket and foliate. Hydraulic tested to 250 psi. , may be260.
Thank for your suggestions
H. P.

Re: separating a very reluctant flanged joint

Posted: Thu Apr 16, 2020 2:09 pm
by Mike Rometer
Great that it's done! :D