A ball valve for fluids comprises a body (11) provided with an inlet and an outlet (12, 13) and with an inner chamber (14) in which a ball element (15) having a main communication passageway (17) passing through the ball element itself is rotatably received. The ball element is rotatable between an angular position at which the valve is completely closed, said passageway being disposed substantially transverse to the inlet and outlet, and an angular position at which the valve is completely open, said main passageway being aligned with the valve inlet and outlet to create a communication therebetween. The ball element (15) comprises a secondary communication passageway (19) of a reduced section disposed laterally of said main communication passageway. The secondary passageway is 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 completely open and completely closed positions.
A method of forming a ball valve element for a rotary ball valve assembly, the method comprising the steps of: (a) inserting an impedance element through an insertion opening of a ball valve element into a bore; (b) forming a fluid opening in the ball valve element which is non-rectilinearly aligned with the insertion opening and which communicates with the bore; and (c) sealing the insertion opening. A ball valve element for a rotary ball valve assembly formed using such a method; and a rotary ball valve assembly comprising a ball valve element formed using such a method are also provided.
