Glued tube-to-tubesheet joints

[Stanman1]

In the many years that I have been studying tube-to-tubesheet connections, I have studied welded, expanded, welded and expanded, hydraulically expanded, explosive expanded, explosively welded (EXW)combinations of hydraulic and/or explosive expanded with roller expanded hybrid and combinations of hydraulic and explosive expanded hybrid and various tube and tube hole enhancements such as grooves and threads. I have also studied joining tubes to forged nipples on the inner face of the tubesheet and to the vicinity of the inner face by similar means. However, I have not found any literature on joining tubes to tubesheets by adhesive means despite a lengthy web search. A substantial listing of papers on the subject is available at

http://www.mgt-inc.com/tube_to_tubesheet_joints.html.

My question is, "Does anyone have experience with joints made using an adhesive to join the tubes to the tubesheet for high temperature and corrosive service?"

 

[rmw]

Stan,

I wonder what you have been sniffing lately.

How are glass heat exchangers affixed?

rmw

 

[moltenmetal]

rmw: with o-rings, hence their temperature limitations. The solid glass ones are done by fusion.

Does solder or braze qualify as glue? Similar, but not quite I guess...

 

[Stanman1]

Glue, of course. You can make your own assessment if you attend the course, "Shell-and Tube Heat Exchangers: Mechanical Aspects" next month in Houston with all the other glue sniffers.March 26 through 28 at the Hotel Derek. I'll be glad to share some of the sniffing glue with you.

Best regards,

Stanman1

 

[deanc]

Stanman1,

More common then one would think. Have info. and will speak with Bob L. I have documents on tube expansion I would like to donate to your collection,some very old. Boulder address?

Loctite makes a two part sealant for weld porosity that works good if applied prior to the roll expansion.

 

[Stanman1]

Thanks DeanC. Boulder address is MGT Inc., 4390 Caddo Parkway, Boulder, CO 80303-3607. Incidentally, Dr. GEO Widera at Marquette University is looking into setting up a library of papers in the list I prepared so investigators can get a head start on literature searches.

So far as Loctite is concerned, I am well aware of how we used it on hard to seal expanded joints, but to the best of my knowledge it is not suitable for making glued only joints. A great part of my work in recent years has been on closed feedwater heaters which may have tubesheets 22-inches thick. Typically for these heaters, the forged steel tubesheet has a weld overlay and the manufacturer welds the tubes to the overlay with filler metal to give a minimum leak path of 0.7 to 1t (t = tube wall). Then the manufacturer expands the tubes into holes prepared with annular grooves. As you can imagine, roller expanding to expand tubes into such thick tubesheets is not a simple or convenient matter and the principal heater manufacturers now use explosive or hydraulic full depth expanding to accomplish the expansion. My paper, "Hybrid Expanding Revisited" discusses combinations of hydraulic and explosive expanding so will not go into detail here. It has some microphotos that show sectioned and polished mockup specimens. You can see the paper in the Journal of Pressure Technology.

If the manufacturers could make such joints using an adhesive, it might save considerable money and would have the advantage of not deforming the tube by expanding which leaves a region of high tensile stress at the transition between the expanded and unexpanded tube.

Stanman1

 

[unclesyd]

We had several fairly large shell and tube graphite heat exchangers that had the tubes cemented to the tube sheets. I believe that the adhesive base was Furan.

I have also tried to use an adhesive, epoxy, on SS tubes as a sealer to mitigate SCC.

 

[deanc]

Stanman1

Understand and thanks. Please check your email at mgt.

 

[rmw]

Stan,

You have a good sense of humor. Tongue-in-cheek is hard to do in print. I'd love to do the Houston thing. I looked long and hard at the notice when I got it, but I can't make it this year. I have to be out of the country. Have a good session.

To the others, go sniff some glue with Stan. It'll be good.

rmw