Flange thickness verification between the bonnet and body

[zhlin]

I have a question regarding strength verification between the bonnet and body of a valve.

Please see the attached drawing, which is for a manual gate valve.

ASME16.34 only has bolting strengh verification. How about the flanges on the body and bonnet? Are there any formulas?

If using ASME Sec VIII div 1's flange formulas to caculate them and if the stress at the hub exceeds the allowable, is it acceptable since the geometrical shape at the hub is not exact the same as the ones in the code?

Thank you very much in advance.

 

[gerhardl]

Please note that I am not an expert either on ASME nor on strength calculation, but after my opinion the answer to your question is a clear no.

The reason I beleive this is that the only ones able to answer if this is acceptable or not is the issuer/responsible organization for the standard.

Secondly is that the question you ask is if the data exceeds given limits (more than standard allows) you can 'borrow or calculate in' some extra strength from other parts of the construction connecting to the flanges calculated.

A standard is usually to be seen as straightforward, all safety limits already incalculated in figueres given.

 

[zhlin]

Thank you. That is what I thought.

Now I need to find solutions.