Flush valve for low water volume toilet

In a toilet having a bowl, a tank connected to the bowl for holding a quantity of water for draining into the bowl through a drain outlet in a bottom wall of the tank, a ballcock valve mounted in the tank and connected to a pressurized water line, a float connected to the ballcock valve for turning the ballcock valve ON and OFF in response to a water level in the tank, and a manually operated flush actuator mounted on the tank, the ballcock valve further having a filler tube for filling the tank with water from the water line and a refill hose for refilling the bowl with water from the water line, the improvement comprising:

• a drain stopper seat mounted over the drain outlet and having a generally cylindrical central passage through which water from the tank can drain into the bowl, the stopper seat including a pressure chamber, a plurality of downwardly directed circumferentially spaced orifices in an interior wall of the stopper seat communicating with the pressure chamber and with the central passage, and a fitting communicating with the pressure chamber;
• a filler hose coupled between the filler tube and the fitting of the drain stopper seat;
• a stopper sized for sealing the central passage through the drain stopper seat when in a lowered position so that water ejected from the orifices will fill the tank and for opening the central passage when in a raised position so that water ejected from the orifices will join water draining from the tank through the central passage;
• means for mounting the stopper for vertical reciprocation between the lowered position and the raised position;
• means for connecting the flush actuator to the stopper so that manual operation of the actuator will cause the stopper to move upwardly from the lowered position to a raised position;
• and
• an overflow tube having a lower end coupled to the drain outlet of the tank and an upper end for receiving a remote end of the refill hose of the ballcock valve.