Metallic seals for ball valve

摘要

A ball or spherical plug valve has a pair of annular metallic seal rings mounted in grooves in the valve chamber around the inlet and outlet passageways of the valve body. Each metallic seal ring is of a one-piece generally uniform angled cross-section to form a leg portion and a free lip portion. The free lip portion extends transversely of the longitudinal axis of the passageways and a substantially continuous line contact is provided between an inner annular edge portion of the free lip portion and the valve member. The lip portion is bent from a free position substantially perpendicular to the leg portion to a substantially frusto-conical position when the valve is assembled so the seal ring acts as a spring to urge itself against the ball valve member to maintain sealing contact.