saddle pressure vessel

[maizo]

How to determinate the distance between the two saddles of an horizontal pressure vessel?
Regards!

[Ali366]

maizo

Stresses in shell due to saddle loads need to be specified. You can use Zick method or do an FEA. If these stresses are within allowable limits, there is no problem with the saddles.
Take a look at "Pressure Vessel Design Manual" by D.R. Moss. If you have got the 2003 edition of this book, section 3-10 describes the zick procedure and is quite easy to follow.
To give you an idea about distance between saddles, they should not be farther than 20% of "Tangent to Tangent Lenght" from the nearest tangent line. e.g. if TTL is 10m. then each saddle should not be more than 2m away from the nearest tangent line. There is a interesting chart in above-mentioned section which suggests the maximum distance of saddles from the nearest tangent line for a particular vessel with known thickness, length and radius. (Source of chart is from AWS).
But don't forget that above chart is just a suggestion and after selecting the location of saddles, stress analysis must be performed (zick, FEA or other methods) to evaluate the shell and heads under support loads.

Cheers,

[maizo]

thank's a lot!

[tony_black]

Yes, Ali366 is correct - however, to describe the issue in a more "practical" sense - please see the attached excerpt paragraph 13.9.1 from "Coulson and Richardson's Vol 6"

In short - you want to start with an analysis where the bending moments across the saddles are equal to the bending moment in the mid-span. And (from the design of a uniformly, loaded, simply-supported beam) this occurs when the supports are placed 21% of the span in from the ends. Then, most oftenly, to avoid the need for stiffening rings at the saddle because the shell will want to "ovalize" at the supports (if far removed from stiffening effects) - many designs push the saddle supports farther outwards towards the heads to gain stiffening from them (and avoid extra stiffening all together).

[maizo]

thank you for your help tony!i have found more details in pressure vessel design handbook.thank you all!

[FATHI]

..The full demonstration and derivation of saddle design and Zick formula is given in :
1/- PD 5500 ( Appendix G)
2-/ French Code CODAP
3/- Pressure Vessel design by Bednar.

Items 1 and 3 could be found in this site...

All is a around beam on two supports, the weight of steel and fluid are both along with the internal pressure are all included , the sshear load at saddle location too

[Abdel Halim Galala]

The distance between the two saddles determines the distance from saddle to vessel tangent line, and the last distance has a great and direct effect in determining the various stresses at saddles and vessel itself. These stresses in vessel on two saddle supports is very important to be analysed by using ZICK analysis.
Download the following ZICK calculation:

[link Point to another website Only the registered members can access]
A reference to that calculations is from manual "Pressure Vessel Handbook" -10th Edition-Megyesy:

[link Point to another website Only the registered members can access]

[cosili]

Hy,
It is very simple to use FEA analyses.
Please take a view into FE/Pipe tools, that was made by Paulin Research Group.
A lot of template it is inside, regarding your job.
All the best,
Cosili

[ardansyahputra]

Hy,
It is very simple to use FEA analyses.
Please take a view into FE/Pipe tools, that was made by Paulin Research Group.
A lot of template it is inside, regarding your job.
All the best,
Cosili

Do you have the software of FEPipe ?
Please.

Thanks

[CarlosBatista]

Fellow i have the spreadsheet for this calculation if you need let me know

[maizo]

Please send the spreadsheet my email is aladin.mza@gmail.com

[ridestar]

can you send the spreadsheet at ridestar_94@hotmail.com
please,
best regards