2 replies to this topic

[mdteng]

Hi.
I'm tying to calculate the saddle supports for an horizontal pressure vessel with 3 saddles.
Zick's method only is applicable for 2 saddle supports.

Does anyone know about a publication or good book to find a method for calculate the stresses ofr a vessel supported with more than 2 saddles?

Thanks

[Art Montemayor]

Mdteng:

I have stated this so many times in the past that I stopped counting. The answer is:

Obtain Eugene Megyesy's great Opus, "Pressure Vessel Handbook". My copy is the 5th Edition. I understand that there is an 11th Edition out. This is what I have described as the most practical and useful Engineering book ever published. You can find it and buy it on the Internet bookstores.

As an aside, why would you insist on using 3 saddles if only 2 will suffice? Every engineer that I've ever worked with has limited the saddles used on horizontal, cylindrical pressure vessels to only 2 saddles. The reason for this is obvious: it's simpler and much more practical because it is an easy way to support and also allow the vessel to expand on one sliding saddle. But if you are stuck on a 3 saddle design, go to it.

[mdteng]

Thanks Art.
I have this book, but it describes the zick method and it's limits of applcability is 2 saddles. Same case with the Moss' book

The porblem arise because in Claus Sulphur plants the reaction furmace and the waste heat boiler are welded together and both equipments has 2 saddles, therefore they behavior toghether is like a vessel supported for 4 saddles.

All of the manufacturers of this kind of equipments did not calculate the real stresses due to this support configuration, what they do is to over-reinforce que contact zone between shell and saddle and not provide any calculation. Sometimes they provide calculations for the two vessels splitted, but it does not reflect the operational behavior of the equipment.

We shall always use a FEM analysis for these type of vessels.

Thanks Anyway