Bundles for large vertical heat exchangers
Bundles for large vertical heat exchangers
(OP)
Anyone have experience in determining whether a cradle is needed for lifting the bundle for a large vertical exchanger from the horizontal position to the vertical position for installation in the shell? Cradle ostensibly is needed to prevent excessive deflection of the bundle in the horizontal position.





RE: Bundles for large vertical heat exchangers
Cheers,
gr2vessels
RE: Bundles for large vertical heat exchangers
Is this insertion being done where the bundle and shell are manufactured, or at a different site.
There is a lot more that you can tell us about this bundle and/or shell before we can give a decent answer.
rmw
RE: Bundles for large vertical heat exchangers
RE: Bundles for large vertical heat exchangers
The aspect of a "mock" shell is often required for the purpose of testing the bundle, possibly more common if the HE design is for differential pressure.
RE: Bundles for large vertical heat exchangers
RE: Bundles for large vertical heat exchangers
Error of judgement of an over zealous engineer might not be a very technical reason, but could be a plausible explanation.
However, from this end I cannot see how did you interpret the use of the craddle as installation aid. It could be usefull for transport purposes, including horizontal and vertical lifting, but I'm unable to see any construction engineering logic in lifting the bundle with a cradle, insert one end of the bundle in the vertical shell, bring another crane, hook up the cradle, disconnect the bundle somehow without crushing the whole installation, remove the cradle, etc...A simple task made incredibly complicated and dangerous. Is it possible that there might be an error in your interpretation?
gr2vessels
RE: Bundles for large vertical heat exchangers
If you are talking about shell and tube heat exchanger gr2vessels has already given you very good advice.
Hope it helps.
Ibrahim Demir
RE: Bundles for large vertical heat exchangers
RE: Bundles for large vertical heat exchangers
It could then be used for rotating the bundle once it reached site.
rmw
RE: Bundles for large vertical heat exchangers
The operator did not properly read the lifting procedure and broke one of the hydraulic cylinder and had to wait to get a new one from the US.
There are some companies do the lifting with simple cradle with wire ropes, however they do take some risks on the tube bending ( not crashing) and bouncing during the lifting and in air. Rotation and control of the bundle during the lifting and in air are not easy and require very slow operation, and still risky.
So this is the job you need to do right, and you must not take risk on the manufactures bundle. So, you are the one to make the right decision what to do and how.
Kind regards,
Ibrahim Demir
RE: Bundles for large vertical heat exchangers
Please read "... manufactures bundle" as "....manufactured bundle" in the last pharagraph.
Kind regards,
Ibrahim Demir
RE: Bundles for large vertical heat exchangers
RE: Bundles for large vertical heat exchangers
Using the parallel axis theorem, it can be found that the stiffness of the bundle is very large. So, as long as the tube to tubesheet joint is adequate to transfer the tensile loads from the lifting operation (I have not done calculations to see if there would be a combination where it would not be - I would think if the joint meets Code requirements, it will be quite strong enough for the loads during lifting and rotating from horizontal to vertical.
We have a few vertical bundles at our site, one very large, with about 7000 tubes 3/4" diameter. We have sucessfully lifted all of these bundles vertically out of the shell, rotated to horizontal, cleaned and inspected, then lifted back to vertical and reinstalled without any damage to the bundle. In no case have I calculated any need for a cradle.
Our bundles do have floating heads at the bottom end, with lugs or trunnions which are used for the tailing crane. So long as the sling is not put around the tube bundle itself, no damage will occur to the tubes.
I agree a cradle could be beneficial for shipping puroposes, but if it is not needed for lifting, then I would recommend removing it before lifting. Trying to remove it after getting the bundle to vertical could be inviting an accident.
Test shells are a completely different matter - such a shell may be very useful for leak testing once the bundle is removed from its "normal" shell, but again, unless calculations prove it is necessary for lifting, I would not use it during the lifitng operation.
RE: Bundles for large vertical heat exchangers
RE: Bundles for large vertical heat exchangers
Are the tubes 1.5" (see your second post) or 3" (see your 5th post?
RE: Bundles for large vertical heat exchangers
RE: Bundles for large vertical heat exchangers
Cheers,
gr2vessels
RE: Bundles for large vertical heat exchangers
Fins are easily crushed
The bundle itself will be stiff enough to lift
RE: Bundles for large vertical heat exchangers