Threaded Seat Ring, Ball Valve

[bzandy]

the technical specification in brief below:
Ball Valves, flanged ends raised face, threaded seat ring, controlled hardness, Body A216 WCB, regular port, ball SS 304.
Now I am very curious about the threaded seat ring used in big size(2"~16") ball valve manufacturing? because I rarely find this kind of requirement according to my experience, what's more the size of ball valve can be such big up to 16", so how can the reliable seal performance can be formed between threaded seat and Ball?? hope anybody in this form can share some useful knowledge about this kind of configuration. Many thanks in advance!

 

[JimCasey]

I can't think of a single ball valve with a threaded seat ring, altho' some may have a threaded seat ring RETAINER.

 

[DrJim]

bzandy,
This sounds to me like a reduced port, floating ball, one piece body with end entry ball/seat package which is retained by a threaded ring. Typically low pressure 150/300 class. Widely used design, but not too popular - probably due to sealing issues. In the bigger bores, the issue of ball weight and its effect on the seats need to be addresses. The seat are typically the only mechanism supporting the ball weight. Controlled hardness indicates that the valve is being promoted for use in NACE MR0175 (sour gas) applications.
Good luck.