Core Structural Components
The core component of a ball valve is the ball, which features a through-bore; it is rotated by the valve stem and works in conjunction with the valve seat to achieve a seal.
Valve Body: The main structure that withstands medium pressure and provides mounting support for internal components.
Ball: The core opening/closing element; its surface may undergo hardening or lining treatments.
Stem: Connects the operating mechanism to the ball and transmits rotational torque.
Sealing System: Comprises seat seals (soft seals typically use PTFE; hard seals use metal alloys) and stem packing to prevent medium leakage.
Complete Operational Process
Fully Open State: The ball's through-bore aligns perfectly with the valve body's flow passage; the medium passes through in a straight line with virtually no flow resistance, resulting in a pressure drop near zero.
Fully Closed State: The ball rotates 90°, positioning the through-bore perpendicular to the flow passage; the solid body of the ball completely blocks the flow path, achieving zero leakage through the tight fit between the seat and the ball.
Regulating State (V-port ball valves only): The ball features a V-shaped notch; rotation allows for linear adjustment of the flow area, enabling continuous flow rate regulation.