Torispherical Head Reinforcement 2

[gvc99]

A customer wants to weld a circular "tank plate" into the center of a flanged and dished (torispherical) head to attach a magnetic mixing device. After welding the "tank plate" becomes a integral part of the vessel head. It is being treated as a "prefabricated pressure part" per UG-11. The "tank plate" does not satisfy the thickness requirements of Section VIII Division 1. Can a reinforcement, such as an external ring of material, be added outside the periphery of this "tank plate" to compensate for the insufficient thickness? The magnetic mixer does not pentrate the wall of the "tank plate".

 

[Tankman650]

UG-11 requires that the part meet all the requirements of the code. Not meeting UG-27 means it does not satisfy UG-11.

I am not aware of a method to reinforce this if it is not shown in UW-16 or UG-37.

 

[gvc99]

Could the addition of reinforcement outside the area of the tank plate that would satisfy the requirements for reinforcement of an opening the size of the "tank plate", along with a determination of whether or not the the "tank plate" thickness can satisfy the the thickness requirements for a flat head of the diameter of the "tank plate" be submitted as a Section VIII, Division 1 code case? Is the engineering rational for reinforcement approach sound? I believe that a case can be made that this approach satisfies the intent of the Code in this case.

 

[twistobar]

Hello, gvc99:
Look through the recent Code Cases. The one of possible help was called "Local Thin Areas", if I remember correctly...
Regards,
Oleg

 

[Estassoc]

GVC99,

If acceptable to your client and conforms to magnetic mixer installation requirements, you can provide an adaptor
plate that conforms to CODE requirements welded to the torispherical head and then weld your mixer tank plate
to this adaptor plate.