Quote Originally Posted by AnandV View Post
You could start with searching for examples similar to yours. Are there any products on markets similar to what you are tyring to design etc.
I have searched, and I came across the "breech-lock" closure.
Looking to the pictures I found about this type of heads, I think this is exactly what I'm trying to accomplish.

It is a flat head, inserted in the channel, and locked with the threaded ring.
The thickness required at the thread in the channel is half the thickness required in the channel shell (only longitudinal stress acting).
Because the thread will hold the complete force created by the pressure on the head, the only thing to do is to secure the threaded ring with small bots. (And to take care the channel shell is strong enough of course)

It is possible to use a bolted flat head connection (bearly), but as you can see in my calculations, it is a 17,5 tons heavy part. I would like to avoid this and use the smaller version (=breech lock).

It is necessary to have this opening. Close the opening by welding would be easier, but is not allowed. It is necessary to have this opening.