Ball Valve
A ball valve is a quarter-turn valve that uses a rotating sphere with a bore through its centre to control flow. Turning the stem 90 degrees aligns the bore with the pipe for full flow or turns it perpendicular to shut off flow. Ball valves offer quick operation, tight shut-off with soft or metal seats, and low pressure drop in full-bore designs. In a floating-ball design, line pressure pushes the ball against the downstream seat; trunnion-mounted balls are supported on fixed shafts and suit larger sizes and higher pressures. Bodies are one-, two- or three-piece, or top-entry. Applications range from utility isolation to oil and gas pipelines, and V-port balls suit control duties. Selection considers pressure class, seat material, fire-safe certification and double block and bleed requirements. Standards include API 6D, API 608, ISO 17292 and API 607 (fire testing).
Examples
- Trunnion-mounted ball valve for a gas transmission pipeline
- Three-piece ball valve for process utility isolation
- V-port ball valve for flow control of slurries