length of saddle span?

[shahdadf]

hi,
how i should calculate the length and distance between two saddles(saddle span) in horizontal vessels? which items i should consider?
thanks a lot

 

[chaulklate]

Results can vary, but I have generally gotten best results by keeping the saddle located equal too or less than 1/4 diameter from its nearest head tangent point.

 

[shahdadf]

that is enough for every length?

 

[JStephen]

Try a google search for saddle analysis by Zick. This is also covered in PV handbooks, in AISI plate books, etc.

 

[chaulklate]

As I said, results can vary, but it's a pretty good starting point. I have found closer to the head is better. JStephen suggested doing research on Zick, I would follow it. I think Zick puts a maximum limit of 1/5 of the span for the location of the saddle from the head tangent point.

 

[BarryEng]

Do a search on 'Zick' (search tab at the top of this page), in the boiler & pressure vessel forum for further info of this topic.

One site (thread?) had a copy of the original Zick paper of 1951.

I have downloaded a copy of the paper but I don't know whether the thread is still current.