Abstract: A rotary ball valve includes a seat support integral with the valve body, a rotatable ball, a movable seat support, a retaining ring, and, on opposite sides of the ball, thin annular seating rings made from a material, such as tetrafluoroethylene. When the valve is assembled, the seating rings are deformed to engage the ball and supports and undergo a small amount of cold-flow outwardly toward interior passage walls of the valve body so that the outer periphery of the seat rings engages and forms a seal between the ball member and the interior passage wall. The seat-engaging surfaces of the seat supports each have grooves into which the seating rings cold-flow during valve assembly. Ribs are thus formed on the seating rings which keep the seats from rocking. The valve also provides an improved stem seal, including a Belleville washer confining a tetrafluoroethylene washer. In addition, the valve includes a handle having a novel projection for limiting movement of the ball to 90.degree.

Abstract: A rotary ball valve includes a seat support integral with the valve body, a rotatable ball, a movable seat support, a retaining ring, and, on opposite sides of the ball, thin annular seating rings made from a material, such as tetrafluoroethylene. When the valve is assembled, the seating rings are deformed to engage the ball and supports and undergo a small amount of cold-flow outwardly toward interior passage walls of the valve body so that the outer periphery of the seat rings engages and forms a seal between the ball member and the interior passage wall. The seat-engaging surfaces of the seat supports each have grooves into which the seating rings cold-flow during valve assembly. Ribs are thus formed on the seating rings which keep the seats from rocking. The valve also provides an improved stem seal, including a Belleville washer confining a tetrafluoroethylene washer. In addition, the valve includes a handle having a novel projection for limiting movement of the ball to 90.degree.