Seat insert for a cryogenic ball valve

A method of preventing leakage in a valve, comprising:

• providing a valve comprising a valve body, a ball selectively rotatable within the valve, a seat insert cavity formed within the valve body, and a seat insert assembly comprising:
• a seat insert comprising a plurality of sealing lips forming a cavity;
• and a support ring engaged with an inner surface of the plurality of sealing lips in the cavity and configured to bias the plurality of sealing lips outwardly against a portion of an inner surface defining a seat insert cavity, wherein at least one sealing lip of the plurality of sealing lips comprise sealing bumps, teeth, or undulations and have a concavity between each of the sealing bumps, teeth or undulations, wherein the support ring comprises an outer surface and an inner surface, wherein at least one of the outer surface or the inner surface of the support ring is angled outward where it engages the plurality of sealing lips in the cavity;
• operating the valve;
• selectively rotating the ball to prevent fluid flow along a flow path through the valve;
• and
• forming or maintaining a first sealing interface between a first sealing surface of the seat insert and the ball to prevent leakage through a first leakage path and simultaneously forming or maintaining a second sealing interface between a second sealing surface and an angled wall to prevent leakage through a second leakage path while the ball is selectively rotated to prevent fluid flow along the flow path through the valve;
• and
• using bumps, teeth, or undulations on at least one sealing lip of the plurality of sealing lips to allow continuous engagement with the sealing ring and seat insert cavity in a cryogenic condition, wherein the support ring has a generally trapezoidal cross-sectional shape.