Hole in Pressure Vessel Flat Head ASME BPVC Sec VIII, Div 1 2

[Doodler3D]

Overlords,

I have a flat head vessel with a hole, outer dia ~ 40", hole diameter ~ 14" for 120 psig (1" thick steel plate). The hole is for a bearing that supports a shaft to drive a paddle mixing assembly (There is no nozzle). I've used UG-34 to begin with but got lost when it came to evaluating the hole. Is this to be evaluated using UG-36/39/43? Or do I refer Roarks or other handbooks. I'm a bit lost.

Thank you.

 

[Doodler3D]

The attached picture is for further illustration. The vessel does not need a code stamp but the customer prefers code calculations.

 

[Doodler3D]

To further elaborate,

ASME UG-34 recommends a minimum thickness of around 15 mm. The FEA analysis assumes peak stresses at around 20000 psi for a 34000 psi yield allowable. So i'm left scratching my head as to how to use the code to keep the customer content.

 

[cbPVme]

You can either assess the excess cross sectional area around the hole per UG-39(b)(1) or you can increase the value for variable 'C' in the UG-34 equations per UG-39(d).

 

[SnTMan]

DoodlerDaru UG-39 would be the "proper" conventional approach, assuming it meets the restrictions therein.

A non-conventional approach I have used is to treat the head as a loose ring flange under Appendix 2, again assuming the relevant restrictions are met.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Doodler3D]

@cbPVme, @SnTMan Thank you

 

[Compositepro]

How can it be that a 120 psi vessel of that size does not require a code stamp? You show no closure detail either.

 

[Doodler3D]

@Compositepro, 120 PSI is a pressure confinement calculation in case the shaft comes loose. It was established by a previous employee who is no longer with the organization. The shaft spins at 1000 rpm and mixes two 'powders'. I'm fairly new to the job and I'm as baffled as you. The customer wants ASME calcs so I was thrown into the pit.