×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Pressure vessels

Pressure vessels

Pressure vessels

(OP)
please can any one help with how to derive the fromula for Head Weight of an ellipticacal head

RE: Pressure vessels

An exact derivation would be a tough math problem based on a triple integral in cylindrical coordinates. An ASME S.E. head is not a perfect ellipse, so you would need to come up with some complex formulas for your boundary conditions...

If you are just looking for close enough, I think there are good formulas for determining the volume of an ellipse based on the two radii.

When asked, I actually find it a whole lot easier to whip open solidworks and model the head. It takes less than 5mins, and I would feel a lot more comfortable with the results.

Good luck!

RE: Pressure vessels

I just look it up in my red rubber ball elliptical head tables :)

Regards,

Mike

RE: Pressure vessels

I use the 2-radius method.
That's not an exact value for a true ellipse, but then again, the head you buy is not necessarily any closer to that elliptical shape than what your calculation is.
If you model it in 3-d cad, you can't easily allow for thinning, so you still don't have an "exact" number. Just a different approximation.

RE: Pressure vessels

Aplogies if this post appears twice...experiencing some issues over here...

I calcualte/estimate surface area of a 2:1 head using 1.084D^2, multiply by thickness to get volume of steel, then multiply by density of steel used to get weight. I use 489.6 lbs/cuft for carbon steel. This method does not capture any straight flange that may be present so figure that out using cylinder formulas and add the two together.

It's an estimate but fairly reliable. You can be more precise by using mean diameter of the head based on actual thickness.

RE: Pressure vessels

You can use the factors in UG-37 (Asme VIII div 1) to convert from elliptical to spherical radius and do an estimate from there.

RE: Pressure vessels

Table UG-37*

RE: Pressure vessels

Use CAD Software and do correct constrain for lines.

RE: Pressure vessels

Thanks, pennpiper!

RE: Pressure vessels

what not ask the head manufacture for the disk dia before forming, and minus whatever being machined off the SF.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources