Patent ID: 7044436

Claim:
A ball valve for fluids comprising a body provided with an inlet and an outlet and with an inner chamber in which a ball element having a main communication passageway passing through the ball element is rotatably received, the ball element being rotatable between an angular position at which the valve is fully closed, with said passageway being disposed substantially transverse to the inlet and outlet, and an angular position at which the valve is fully open, with said main passageway being aligned with the valve inlet and outlet to constitute a communication therebetween, the ball element comprising a secondary communication passageway of reduced section disposed laterally of said main communication passageway, the secondary passageway being designed to bring the valve inlet and outlet into communication with each other when said ball element is in a range of intermediate angular positions between said fully open and fully closed positions, wherein the secondary passageway is not aligned either the inlet or the outlet when the ball element is in the fully open position, the secondary passageway being formed by a plurality of packed discs received in a seat in said ball element, the discs being provided with a plurality of holes defining segments of said secondary passageway.