REINFORCEMENT OF OPENING IN ELLIPTICAL HEAD 4

[dygorane]

Hello there, We have 36" id elliptical head and we need to put 24" manway on that. Manway is cutting through Knuckle of head. Per UG-36(b)(2)there is no limitation on size of the opening as long as you reinforce it.

But can nozzle cut the knuckle of head? does code have any limitation for this anywhere? Vendor says he can reinforce it with internal projection. Any reference or personal experience?

Thanks in advance for your help.

 

[vesselfab]

DO YOURSELF A FAVOR

forget the head and the neck on that manway

make a cone for that top head directly to the manway flange

 

[doct9960]

Is the manway not located in the center of head?

If the head is 2:1 ellipsoidal and the manway is located in the center of the head, the opening is NOT in the knuckle region.

 

[vesselfab]

i did a quick layout assuming just a wn flange in a head.
with a cone shown just as a reference to show you how it works.

this does away with reinforcement problems

most folks don't think about

 

[saplanti]

dygorane,

Why do not use a reducer 36"/24" by considering the materials and thicknesses of the shell and the reducer instead? It will engage additional 610 mm.

Or if the cylindrical shell/ pipe has larger thickness than the reducer you may not use it, however you may use a cone transition between two sizes unless you have a space problem to fit. Sometimes rolling the cone that has high thickness to small diameter can be a problem. The cone may be hot rolled but it may require a specialised manufacturer.

Therefore you will not have any reinforcement problem.

Hope this helps,

Ibrahim Demir

 

[saplanti]

dygorane,

Another way is to use a forged reverse flange in accordance with ASME Sect VIII Div 1 Appx 2 instead of using a head with large opening.

Kind regards,

Ibrahim Demir

 

[Christine74]

"this does away with reinforcement problems"

Possibly. See Appendix 1-7 & 1-8.

-Christine

 

[vesselfab]

1.7 Did apply in the elliptical head version and the available reinforcement is much smaller than the code allowable limits and it just gets into a can of worms when design and proving an opening that it's diameter basicially 70% of the diameter of the vessel.

1.8 does apply...of course.

but again, this solution is to do away with the problems of large diameter openings in small elliptical heads.

reinforcing cones is much easier tha reinforcing the original opening.

less material, less labor, less engineering, less problems.

makes for a much cleaner product

 

[JoeTank]

Maybe a 36" manway would solve the problem? Just use a slip-on flange.

Joe Tank

 

[dygorane]

Thanks to all of you for posting your valuable suggestions. finally we are going with Cone directly connected to 24" flange instead of manway and head.

Thank you again for replying.

Cheers
dygorane

 

[jehan17718]

dygorane,

It will seem a bit odd to post at this stage.

Another option would be to have body flanges. In other words the 2:1 SE head is welded to a body flange. We commonly opt for body flanges in vessels <= 36" instead of manways. Is the vessel under question have internal trays/ pakings? If yes, then its better to have a flanged column without manways.

This will eliminate the 24" NPS manway and at the same time permit access to the vessels inside.

You just need to check if there is room/ space to remove the head.

-jehan