ASME Heads 1

[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...

 

[doct9960]

At the same inside diameter, the ASME F&D head is shallower than the 2:1 SE head. The shallower the head, the less resistance to pressure.

For comparison between heads, check out the charts in this link...

http://www.pveng.com/Charts/Charts.htm

 

[JoeTank]

The decision to use and F&D head or an ellipsoidal head is not a techniocal issue. It's an econmic issue. The least cost alternative is usually the choice.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[JStephen]

Ditto to Steve's comment.

If you're specifying a tank, just show an oval-shaped head and let the tank designer work out the details. Depth and capacity would vary slightly with the head shape.

If you're actually designing the tank, work out the thicknesses either way, and get pricing on the heads. Your head supplier may can give you more info on what they normally see.

As well as the cost of the head itself, there could be some variation in the reinforcing required in different shapes of heads.

 

[jodyed]

I have calculated f&d's and 2:1 ellip's heads. Generally the elliptical heads will hold more pressure than the f&d, however, other factors also come into play, i.e., Is the tanks orientation vertcle or horzontial ? Does the horozontial unit have a clean-out or manway in it ? These things will have an effect on your calcs. Be sure and look at any required EXTERNIAL pressure requirnments. Remember your cost implementations and conceder using the f&d with RE-PADS if the elliptical's are more expensive.

Hope this helps some.

jodyed