Ball Valves

These valves can be applied either as a simple ON/OFF isolation device or, when paired with an appropriate actuator and control strategy, as a modulating element to regulate flow. The term ball valve is derived from the spherical, flow-controlling ball located inside the valve body. This ball contains a precision-machined bore (a hole through its center) aligned along one axis so that, when the bore is oriented with the valve ports, it establishes a direct connection between the inlet and outlet passages of the body.

The ball is supported and sealed by PTFE (polytetrafluoroethylene) seats and is typically operated by a quarter-turn motion, rotating 90° from fully closed to fully open. PTFE seating surfaces provide low friction and essentially permanent lubrication characteristics, which contributes to repeatable operation and helps maintain a “bubble-tight” shutoff under proper service conditions. Behind the PTFE seats, elastomeric cushions or backing elements are commonly used to maintain consistent seating load against the ball. This design both stabilizes sealing contact over a wide pressure range and compensates for gradual wear, helping preserve shutoff performance over the service life of the valve.

To prevent external leakage, elastomer O-rings are generally used as stem and carrier seals, limiting fugitive emissions and protecting surrounding equipment from atmospheric release of the process fluid. In the fully open position, flow through the valve is essentially straight-through, which reduces turbulence compared with many multi-turn valve geometries. When the ball port is “full port” (i.e., the bore through the ball matches the inside diameter of the connected pipe), pressure drop is minimal, making ball valves advantageous where energy efficiency, predictable hydraulics, and low head loss are priorities in fluid handling systems.