Valve Disc/Ball

The valve disc or ball is the primary sealing and flow-regulating component within inlet and outlet valves. It functions as a movable element that interfaces with the valve seat to create a tight seal when closed and provides controlled flow passage when open. In ball valves, it's a spherical element with a through-hole; in disc valves, it's a flat or tapered plate that rotates or lifts perpendicular to the flow direction. This component directly determines valve performance metrics including shut-off capability, flow coefficient (Cv), pressure drop, and service life.

The disc/ball operates by mechanical actuation (manual, pneumatic, or electric) to rotate or lift, changing its position relative to the valve seat. In the closed position, it creates a metal-to-metal or soft-seated seal against the seat, preventing fluid passage. When opened, it aligns its flow passage with the valve body ports, allowing controlled fluid movement. The sealing mechanism relies on precise machining, surface finish, and material compatibility to maintain integrity under varying pressures and temperatures.