When fluids flow through a rotary ball valve, its “dynamic” motion creates unbalanced forces on the surface of the closure element, causing additional torque—or dynamic torque. This change to the flow can eventually stall the actuator. An accurate knowledge of the dynamic torque coefficient acting on the ball surface is required for accurate and precise actuator sizing. This will ensure proper actuator sizing to minimize cost and improve reliability.
To read the full Valve World Americas Journal October 2019 special topic article, please contact Brittani Schroeder (b.schroeder@kci-world.com) for the full PDF version.