Butterfly and ball valves both use quarter-turn motion, making them compact candidates for manual or automated isolation. Their flow paths, sealing systems and size economics are different.
Size and pressure drop
A butterfly disc remains in the flow even when fully open. A full-port ball valve can present a nearly unobstructed bore, which may matter for pigging, solids or very low pressure drop. Butterfly valves are usually lighter and shorter, especially at larger diameters.
Shutoff and service
Resilient-seated butterfly valves suit many utility duties; high-performance and triple-offset designs extend pressure and temperature capability. Ball valves offer strong shutoff but can trap fluid in the body cavity. Dirty or crystallising fluids need careful seat and cavity review.
Automation
Both accept compact rotary actuators. Compare breakaway torque, differential pressure, flow-induced torque and required operating time. The installed cost should include mating flanges, supports, actuator sizing and maintenance access.
