What is a Ball Valve?

These valves are often used in industrial, commercial, residential, oil and gas, water treatment, and chemical processing. It features a ball with a through hole in the middle as the closure member. The valve is open when the hole is lined up with the flow bore. The ball is rotated 90° to close. There are two primary designs. A floating ball valve the ball floats between two seats. When the valve is closed the differential pressure forces the ball into the downstream seat aiding in the seal. In a trunnion-mounted ball valve, the ball is stationary, and the seats move (or float) and form the seal on the ball. The seats can be made from a variety of materials from softer materials like PTFE to metal rings. The primary advantages are minimal pressure drop, leak-tight seal (basically zero leakage), and quick quarter-turn opening. The main disadvantages are higher torque to open and close on larger valves, soft seated valves are not suitable for throttling, and can be damaged by the solids in the media.