Ellipsoidal Head 1

[wfn217]

Can anyone tell me how to calculate the MAWP for an 8:1 ellipsoidal head?

 

[vesselfab]

not sure what a 8:1 ellisoidal head is

can you expound on the part?

 

[wfn217]

I have a tank head which is an 8:1 ellipse. The ASME Code only covers a 2:1 ellipse.

 

[prex]

I think you can't, at least staying within ASME VIII.
Your head is flatter than a 6% torispherical head, and the code prescribes a 6% knuckle radius as an absolute minimum.

prex

http://www.xcalcs.com

: Online engineering calculations

http://www.megamag.it

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http://www.levitans.com

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[vesselfab]

Not trying be argumentative....but

I have been around a looooong time
and have never heard of a 8:1 head

Is this appearing on a drawing or what?

What determined that this is a 8:1 head

 

[wfn217]

The U-1 form.

 

[jte]

Consider it a typo. But put your boots on and walk over to the vessel and verify it. By definition, your height of the head from the tangent line will be only 1/16 of the diameter. A 2:1 head height will be 1/4 of the diameter. This should be very easy to measure accurately enough to determine which one it is.

jt

 

[unclesyd]

I have seen heads very similar to this one along with flat, flange on, with very shallow radiuses on low pressure vessels. I don't recall if they were stamped.

http://www.padanafondibombati.com/info/dishedheads/convex/en

 

[Christine74]

See Section VIII-1 Appendix 1 paragraph 4(c).

-Christine

 

[wfn217]

Thanks Christine.