A valve for use in oil and gas production or similar applications includes a plug or other flow barrier disposed in a cavity of a hollow valve body with a metal-to-metal sealing surface that is not reliant on any rubberized or elastomeric material to effect a seal.

A seal assembly is provided for a rotary ball valve an eccentric cammed ball. The seal assembly may include a seal ring disposed within the valve interior and biased toward the ball element of the valve. A seal ring retainer may be threadedly secured to an interior of the valve body, thereby retaining the seal ring in the valve body.

A rotary valve includes a valve body including an opening formed therein, a rotary component received within the opening of the valve body with the rotary component configured to rotate relative to the valve body about an axis of rotation thereof, and a sealing assembly including a hard sealing structure and a soft sealing structure disposed between the valve body and the rotary component. The hard sealing structure is formed from a substantially rigid material and is configured to sealingly engage the rotary component. The hard sealing structure includes a support feature to reinforce the soft sealing structure. The soft sealing structure is formed from a resiliently deformable material and is configured to sealingly engage the hard sealing structure and the valve body.

Systems and methods are disclosed that include providing a valve suitable for maintaining a seal and preventing fluid flow through the valve at cryogenic temperatures. The valve includes a valve body having a longitudinal axis along a flow path through the valve, a ball selectively rotatable within the valve body to selectively allow fluid flow through the valve, a seat insert cavity formed within the valve body, and a seat insert assembly at least partially disposed within the seat insert cavity. The seat insert assembly includes a seat insert comprising at least one sealing lip and a support ring engaged with the at least one sealing lip and configured to bias the at least one sealing lip against a portion of the seat insert cavity to prevent leakage through a second leakage path when the ball valve is selectively rotated to prevent fluid flow through the valve.

An example apparatus is disclosed herein comprising a valve that includes a valve body defining a fluid passageway between an inlet and an outlet, a flow control member in the fluid passageway, a stem coupled to the flow control member, and a bonnet coupled to the valve body. The stem extends through a channel in the bonnet. A section of the channel forms a bore. The bore is threaded. The apparatus includes packing in the channel to form a seal between the bonnet and the stem. The apparatus includes a worm wheel nut threadably engaged with the bore. The stem extends through an opening in the worm wheel nut. The apparatus also includes a worm meshed with the worm wheel nut. The worm is to rotate the worm wheel nut to cause the worm wheel nut to move and adjust a load on the packing.