×
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

Knuckle Radius & Table 1-4.4

Knuckle Radius & Table 1-4.4

Knuckle Radius & Table 1-4.4

(OP)
Hi,

I'm in a situation where there's an existing plant to be installed with a reactor (a vessel actually). The problem is that the vessel itself was fabricated in another plant and running well for now I presume but when I calculate the required knuckle radius it is less than minimum required based on ASME Section VIII.

In ASME Figure UG-36, it is mentioned there that the radius at the large end of the cylinder to cone shall be greater than either of 0.12(R+t) or 3 times the thickness (if not mistaken). Unfortunately our client specify the knuckle radius as 80mm where in the calculation it should be at least 138.6 mm.

This value, 80 mm, was based on the existing plant which the plant already operating. However, besides the GA drawing they didn't have any calculation sheet or provide with any other relevant documents besides the drawing itself.

Referring to Table 1-4.4 also I couldn't get the ratio right (definitely), from r/D ratio we could easily get the height of the cone itself and as predicted, the height also is way off than what is required.

Does anyone have any advice regarding this matter and kind enough to share their valuable opinion.

Thank you

RE: Knuckle Radius & Table 1-4.4

Have you measured the actual knuckle (outside, under the insulation)?

If all you have is a general arrangement (assy dwg) it too might be a simple case of "draw a curve, nobody will ever care what actual knuckle is installed" approximation by an earlier draftsman.

RE: Knuckle Radius & Table 1-4.4

takiyasamsama, Table 1-4.4 applies only to elliptical heads of certain proportions, see 1-4(f)(2).

If your (presumed) toriconical head fails to meet the knuckle radius requirements of UG-36, well given that the vessel(s) are apparently in service, I'm not sure where that leaves you. Vessels are no longer under ASME Code, but more likely NBIC. Maybe a matter for the jurisdiction.

Regards,

Mike

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