A fluid control valve with a rotatable shaft and a ball valve mounted within a flow bore. The ball has one or more V-shaped grooves for controlling fluid flow. In the closed position the ball and walls of the flow bore are in a continuous line sealing contact. The valve may be mounted and opened to enable complete drainage of fluid in the connecting pipeline which is an advantage in sanitary applications. The ball and shaft are part of a removable bonnet assembly with the ball inserted into the flow bore through an aperture in the valve body. A one-piece seal in the aperture provides a static seal between the valve body and bonnet and a dynamic shaft seal.