Ball valves are normally quarter turn straight through flow valves that have a round closure element with matching rounded seats that permit uniform sealing stresses. A Ball valve is popular in many situations where tight shut off is required. The type of seat can vary with the valve pressure rating and materials of construction. Some valve seats may be composed of single molded forms, while other seats with higher-pressure ratings could incorporate a trunnion design where each face of the ball is separately sealed . Ball valves are used in numerous process and utiility applications for many types of fluids. The ball valve can be turned by hand or actuated with pneumatic, hydraulic or electric actuators