Water conserving toilet tank adapter

In a tank reservoir system adapted to be periodically emptied by a flushing operation, the system including a tank outlet situated at or near to the bottom of the tank reservoir with a liftable occlusion valve provided to selectively seal the outlet or open the outlet to allow fluid flow therethrough, the improvement comprising:

• raising the effective height of the tank outlet by providing a hollow extension to extend upward from the tank outlet, the extension including a sealing ring to mate with the occlusion valve in the same manner as the prior seal mates with the tank outlet;
• decreasing the effective diameter of the tank outlet by providing an outlet tube portion, connected to the hollow extension at an interface, for depending into the tank outlet, the inside diameter of the outlet tube being less than that of the tank outlet;
• and
• inducing angular momentum in fluid flowing during the flushing operation by providing a contoured surface, including swirl grooves arranged radially about the interior of a swirl disk portion of the extension, over which the fluid flows, said swirl disk portion being situated at about the interface between the hollow extension and the outlet tube portion.

A retrofit adapter for use in conjunction with a conventional toilet tank reservoir, the tank reservoir having internal components including a tank outlet situated at an empty water level position within the lower portion of the reservoir, adapted such that during a flush cycle flush water is delivered to a toilet bowl through the tank outlet, a flap valve for selectively sealing the tank outlet before and after flushing, for maintaining a filled water level in the reservoir, which filled water level is substantially higher than the empty water level, and flap valve opening means for opening the flap valve to begin the flushing cycle, the adapter comprising:

• an outlet tube portion for depending into the tank outlet such that flushing causes water to flow along a fluid flow path extending through the outlet tube portion, the outlet tube portion having a lesser interior diameter than the tank outlet;
• and
• an inlet portion situated along said fluid flow path, the inlet portion including an inlet opening situated within the reservoir at an inlet level, said inlet level being intermediate the filled water level and the empty water level, the inlet portion including a sealing rim at said inlet opening, said sealing ring being adapted to mate with the flap valve in such a manner that said inlet opening functionally replaces the tank opening during the flushing cycle;
• and
• a swirling inducing contoured surface means situated within the inlet portion in the form of a swirl surface along the fluid flow path near the interface between the inlet portion and the outlet portion, the swirl surface including angular momentum inducing grooves therein to produce swirling in the water as it progresses along the fluid flow path into the outlet portion;
• wherein water intermediate the empty water level and said inlet level, which water would, in the absence of the retrofit adapter, be flushed from the reservoir during the flushing cycle, is retained in the reservoir such that a lower volume of water is utilized in each flushing cycle, said lower volume being compensated for by increased effective pressure attributable at least partially to the induced angular momentum.