Patent ID: 8371553

Claim:
A valve device comprising: a valve body defining a fluid flow duct; a throttle element disposed in the valve body and adapted to be turned about its axis by actuator means via a drive shaft, the throttle element having: a bottom portion that is structured and arranged to extend into the fluid flow duct, an annular ring that is disposed about a periphery of a bottom edge of the bottom portion, a spherical internal cavity defined by a circular wall that is completely open at the bottom portion, and a single variable-shape opening defining a fluid flow passage in the fluid flow duct, the opening disposed through a portion of the circular wall of the internal cavity and having a shape, the shape of the single opening varying progressively around a substantial portion of the circular wall between a fully-open position in which the opening communicates in full with the fluid flow duct, and a fully-closed position in which said circular wall closes the fluid flow duct; a gasket-carrier tube that is disposed within the fluid flow duct; and an annular sealing gasket that is coupled to a distal end of the gasket-carrier tube disposed in the fluid flow duct so as to surround an opening in the gasket-carrier tube, said gasket structured and arranged to continuously maintain contact with the annular ring at least at the periphery of the bottom edge of the bottom portion of the throttle element and with the circular wall of the internal cavity as the throttle element is turned about its axis between the fully-open position and the fully-closed position, and said tube opening and gasket being distal from the axis of the throttle element, wherein said axis does not penetrate said tube opening or gasket as said throttle element rotates about said axis.