Multiple orifice valve with improved turn-down ratio

A valve having an improved turn-down ratio and low-erosion discharge flow, the valve including the combination of:

• a valve body having an internal cavity with an inlet and outlet for fluid;
• an upstream disk rotatably supported in the cavity of said valve body and having two openings for conducting fluids;
• means for rotating said upstream disk;
• a stationary downstream disk arranged in a face-to-face and confronting relation with said upstream disk in the cavity of said valve body, said downstream disk having two openings for conducting fluid from the fluid conducting openings in said upstream disk said upstream and downstream disks having a common central axis extending perpendicular to end faces of the disks;
• each of said fluid conducting openings in said upstream disk and said fluid conducting openings in said downstream disk comprising a circular sector shaped primary opening portion and a secondary openings portion the secondary opening portion including two substantially semicircular supplemental openings, a first one of said supplemental openings being located at a radially outermost position along a first of two radially directed walls defining a central angle of the circular sector shaped primary openings portion and a second one of said supplemental openings being located at a radially outermost position along a second of said two radially directed walls the secondary openings portion of the fluid conducting openings of the upstream disk when the fluid conducting openings of the upstream disk are brought into a turn-down position with respect to the fluid conducting openings of the downstream disk, aligns with the secondary opening portion of the fluid conducting openings of the downstream disk to permit discharge flow from the downstream disk which is essentially always parallel with a plane bisecting the fluid conducting openings of the downstream disk and passing through the common central axis of the disks.