Ball Valve Body Patterns: Full Port, Reduced Port, and V-Port

Ball valve body and ball configurations determine the flow characteristic, pressure drop, and control capabilities. Selecting the correct ball pattern for the application ensures optimal performance and avoids unnecessary pressure drop or poor control resolution.

Full Port (Full Bore) Ball Valves

Full port ball valves have a bore through the ball equal to the nominal pipe size. This provides the lowest pressure drop and is required for pigging service, transfer of viscous or solid-containing fluids, and applications where pipe bore consistency is critical.

• Pressure drop: essentially zero (CV equals pipe CV)

• Required for: pigging, slurry transfer, custody transfer metering

• Larger ball and body: requires more space and weight than reduced port

• Standard for: pipeline service (API 6D), tank bottom valves

Reduced Port (Standard Bore) Ball Valves

Reduced port valves have a ball bore one nominal size smaller than the pipe size (e.g., 2-inch bore in a 3-inch valve). This reduces valve size, weight, and cost while accepting a modest pressure drop penalty.

• Acceptable pressure drop for most process applications

• Smaller and lighter than full port equivalent

• Not suitable for pigging or large solid particles

V-Port (V-Notch) Ball Valves

V-port ball valves incorporate a V-shaped notch in the ball that provides an equal-percentage flow characteristic ideal for throttling and control applications. As the ball rotates, the V-notch opening grows exponentially, allowing fine control at low flow and wide rangeability.

• Rangeability: typically 200:1 or better

• Self-cleaning action: V-notch cuts through fibrous or particle-laden fluids

• Equal percentage characteristic: matches most control loop requirements

• Applications: flow control in chemical, pulp and paper, and food processing

Segmented Ball Valves

Segmented ball (also called characterized ball or fishtail ball) designs use a portion of a sphere rather than a full ball. This provides even better flow characterization and is well suited for control of viscous, fibrous, and slurry media.

Selection Guidelines

For isolation only, reduced port is usually acceptable and cost-effective. For piggable or clean-out service, specify full port. For flow control applications, V-port or segmented ball valves provide the best rangeability and flow characteristics.