Nozzles proximity 1

[Technopriest]

I'm verifying calculations for an ASME vessel vith conical head. On the head there are several, very near nozzles ( they are nearer than double their average diameter).
During calculations I already considered this, using only 5 millimeters of head surface in reinforcement calculation for each nozzle. The nozzles are always spaced more than 10 millimeters from each other.
Do I have to do some additional calculation?
Are reinforcements of the head needed?
Any help will be greatly appreciated.
The vessel will be made of UNS N06022 alloy.


Che Dio ce la mandi buona, o almeno ce la mandi- Massimiliano Eusebi

 

[codeeng]

I'm just guessing but is this for the filter basket on your other thread? If so I suggest you apply a ligament efficiency per UG-53 to your cone thickness calculation.

 

[Technopriest]

Yes, is for the filter I mentioned in the other post.
We employed a joint efficiency of 0.7; is this what you refer to as "ligament efficiency"?

Is this enough?

The question has been rendered useless for the filter in object, as the nozzles are now placed in a different way and the problem no more exist. But I'm still curious, as it's possibile that our workshop will build other machines to be ASME stamped...



Che Dio ce la mandi buona, o almeno ce la mandi- Massimiliano Eusebi

 

[codeeng]

Well first off your filter basket does not need to comply with ASME but I've seen ASME used as a design basis for such components. The ligament efficiency is not the same as joint efficiency. It needs to be calculated per UG-53 based on the size and spacing of the holes. Applying an additional joint efficiency would be optional.

 

[GenB]

I am not reading the Code, but .7 joint eff. seems very i for the aplication and proximity of the connections.
Go to the appendix and review the nozzle calculations,
you may have to not only increase the t of the head but to repad as well. nozzle design may be used to help the connection, thus reducing t of base material.
ER

 

[davidribeiro]

In South Africa, most Petrochemical Refinery standards will not allow toe to toe welds closer than 50mm apart.

I dont think its an ASME requirement, but I'm sure theres a good reason for it.

Dave