US Patent RE39658 Ball valve with modified characteristics

A valve according to the invention having a disk with a shaped opening and one side interfacing with and conforming to the shape of the exterior of the ball or plug. The disk fits inside the port at the seat area, and is secured by a ring. The ring can be threaded into the connection for the fluid pipe line. Alternatively, the connection can have a groove for an internal retaining ring. The disk is positioned so it interacts with the hole in the ball, in such a way that the desired flow characteristics are accomplished.