Abstract: A ball-valve having an apertured ball which is rotated to connect or close off inlet and outlet passages from one another and a replaceable resilient liner encasing the ball and filling the body cavity around the ball and its stem. The liner may include a portion to wipe the ball surface clean as the ball is rotated.

Abstract: A ball valve has a body with opposed coaxial inlet and outlet passages leading to and from a ball chamber containing an apertured ball which may be turned by a handle to open or close the way between the inlet and outlet passages, a pair of sealing rings at the inner ends of the inlet and outlet passages bearing against the ball, the inlet sealing ring being backed by a fixed annular flange, the outlet sealing ring being backed by an annular insert screwed into the inner end of the outlet passage to press the sealing rings firmly against the ball. The inlet and outlet passages have tapered threads, but the inner part of the outlet passage in which the insert is screwed has a cylindrical thread.