SUPPORTS DESIGN FOR SPHERICAL VESSELS

[Fizza453]

Please let me know some good reference book/paper/guide for the support design of spherical vessels? (the vessel is made up of two hemispherical heads butt welded to each other, diameter is 5 meter)
design code is ASME VIII-1.
Thanks in advance.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[fegenbush]

Fizza453,

I don't know about all companies, but the ones I know that build spheres are very secretive about information relating to their design and construction. Generally, FEA is used for the details, but you could probably get a lot of ideas by doing a google image search for spherical vessels.

Sorry I cannot be of more help.

 

[LSThill]

Fizza453 (Mechanical)

Additional information may help you:

http://www.eng-tips.com/viewthread.cfm?qid=281807&page=7

http://www.eng-tips.com/viewthread.cfm?qid=197644&page=62

http://www.eng-tips.com/viewthread.cfm?qid=159493&page=15

http://www.paulin.com

Lesson 25 - Legs on Spheres
(Refert o: Chapte3r section
A sketcho fea typicals phere
7 FE/Pipeu ser'sm anual)
is given below

Leonard Stephen Thill

 

[nuche1973]

If you can find Bednar's book "Pressure Vessel Design Handbook" is a great comprehensive guide for pressure vessels.


"I drank what?!" Socrates?

 

[JStephen]

I don't see that Bednar addresses supports for spheres, though.

 

[jamesl]

Dennis Moss's book has a charpter for field fabricated spheres w/ a table for number and size of legs for spheres up to 87 feet in diameter. If you want to check the stresses at leg to sphere junction, you need to do FEA.

 

[LSThill]

Fizza453 (Mechanical)

Sphere Design STADD Pro. 2003 attach may help you

contact for the file:

http://www.bentley.com

› Products › STAAD.Pro V8i

 

[JStephen]

One thing to note- large spheres are usually leg supported, but the design would be much simpler on a small sphere if you can use a skirt support rather than legs.

 

[Fizza453]

JStephen

Use of skirt would be a costly solution as comapred with legs because we want to place the vessel at a certain height of 2 meter (2 meter clear space between the ground and bottom of the vessel, I mean)

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[Duwe6]

FEA the crotch of the leg-to-sphere joint on a small grid. That will be the structurally "hot" region. Also spce the fireproofing, if any, as something that will not let in and trap water. The USA has had several spheres colapse due to corrosion hidden-under-fireproofing. Good paint helps. Are you allowed red lead [lead oxide & linseed oil] primer?

Red Lead works wonderfully; it is outlawed in the USA because "somebody might eat it".

 

[JStephen]

Duwe6- the last tank that we used lead paint on, was a Corps of Engineers job, where the contracting engineer insisted that lead primer be used because he didn't think some kid would be eating it.

Shortly after that, there was a case where painters blasted lead paint off a water tower and contaminated a whole neighborhood with lead dust, and that introduced extensive shrouding requirements to the area. (And has also introduced extensive OSHA rules dealing with lead-paint-removal workers). So I just expect our US goverment got to spend about a half million dollars at some point removing that lead paint that some kid wouldn't eat.

 

[Fizza453]

Duwe6,

The use of Red Lead is allowed here in Pakistan.
How it works wonderfully, please explain a little.



Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[Duwe6]

I have regularly found red lead primer on tanks from before 1950 that was in Fair, or even in Good condition. No other primer gives that many decades of performance.

It does require a chemical 'strip' when it finally needs to be removed, or you cause what JStephen mentioned. An expensive, heavy-metal mess.