2:1 Elliptical Heads Vs. F&D Heads

[keens]

Gentlemen,

Does anyone know of or have a design standard they use when deciding whether to use a 2:1 Elliptical Head or an F&D Head in their design? I know 2:1 Elliptical Heads are usually used for small and medium diameters, and higher pressures. And F&D Heads are usually used for lower pressures and larger diameters. If anyone has a standard relationship of pressure versus daimeter for these two types of heads, I would appreciate it. Thanks...

 

[zjliang]

From the stress/strength perspective, SE head could retain higher pressure than flat/dish head. But the fabrication cost is higher as well, especially for the diameter vessel. In most cases, flat head is applied as a removeable cover but a head, just like a blind flange. But, the trade-off is the thickness.
Thanks.

 

[Cockroach]

I've never seen a graph relatinng head (pressure)to diameter per say, but there are many which relate bulkhead stress to diameter. I suspect this is what you are after.

On the other hand, it is extremely easy to develop your own formulae based on cross section profiles from Roarks Formulae for Stress & Strain. You should push on your pencil a little and apply some very elementry computations to this problem.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada