Flat bottom for a nutsche filter

[Technopriest]

(sorry for the poor english, I hope this is understandable)
I've got a problem to determine the minimum thickness of a flat bottom for a Nutsche filter.
The system is composed by an integral flange welded on the vessel body and by a flat bottom bolted on the flange.
The problem is that the bottom is made out of two pieces: a flat flange, which is the one that gets bolted on the integral flange, and by a disk wich is wielded in the flat flange. The flat flange is made of a different material from the disk.
The two flanges are in face to face contact (the gasket is an O-ring).
Some hints on formulae or such that I can use to determine the thickness of both the flat flange and the disk?
The thickness of the flat flange should be diminished by the seat for the O-ring or this isn't mandatory in this calculation?
I'm interested in a solution that is good for Europe, but any help will do (at least I'll know if I'm on a good way)


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

 

[mgp]

Did you look in EN 13445 (european Pressure Vessel Code)?

regards

Mogens

 

[Technopriest]

Thank you mgp, but I already searched EN 13445. I found a flat bottom case with soft gasket, and a some limit considerations for minimum peripheral thickness. But as I already said, my flat bottom is composed by two pieces and I'm not sure that what EN 13445 says is applicable. I can't suppose to use the weaker material for the whole bottom, that would rise the thickness to an unbearable level. I can't consider weldings as class I weldings too (weldings efficiency can't raise over 0,85).
Any other source to look at? I'd be glad to find any solution- even ASME or other non-european codes will do.


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