Valve assembly useful for cryogenic applications

A valve assembly comprising:

• a cartridge that comprises a handle coupled to a stem and journaled in a bonnet coupled to an upper end of said stem, and a cage assembly coupled to a lower end of said stem and said bonnet;
• wherein said cartridge is insertable through an upper end of a valve body, and said bonnet is securable to the upper end of said valve body by means of bonnet bolts;
• and
• wherein said cage assembly comprises an off-set C-ball, which comprises a curved face which is coupled to a rotatable C-frame and which is arranged to seal against a curved seat which is located in an aperture formed in a cage, and wherein rotation of said stem rotates said off-set C-ball to permit or block flow through said cage assembly, and wherein an outer surface of said cage and an outer surface of said curved seat are conical, and said valve body has a conical portion, wherein a conical shape of said conical portion complements a conical shape of said outer surfaces of said cage and a conical shape of said outer surface of said curved seat, and tightening of said bonnet bolts to secure said bonnet to said valve body creates a preload force that forces said conical outer surface of id cage and said conical outer surface of said seat to forcefully move to a fully position in said conical portion, and said preload force creates a sealing preload and sealing effect between said curved seat and said valve body.