Ball valve

Claim 1

A ball valve comprising: a valve body having a ball receiving cavity with aligned inlet and outlet passages leading to said cavity, a ball rotatably supported in said cavity between said inlet and outlet passages, said ball having a hard outer surface formed by a thin layer of ceramic material formed of chrome oxide coated thereon and having an opening extending through said ball, first and second ring-shaped seats located in said valve body on opposite sides of said cavity, the inner surfaces of said first and second ring shaped seats defining a portion of said inlet and outlet passages respectively, each ring-shaped seat comprising an annular cast iron member having a concave seating surface adapted to engage said ball, a resilient O-ring located between the back side of each ring-shaped seat and wall structure of said valve body to form a seal between the back side of said seats and said wall structure of said valve body, means for rotating said ball to an open position wherein its opening is aligned with said inlet and outlet passages and to a closed position wherein its opening is out of alignment with said inlet and outlet passages, said ball and said concave seating surfaces of said annular cast iron members being lapped to a close tolerance fit.