Abstract: A dual flush system for a toilet tank, to choice a desired flush volume of water from said tank to flush solids or liquids, depending on the operation of a two-position flush lever, comprising: a latching plate coupled to the overflow tube, having a latching aperture and a tilting gate connected to the flush lever mechanism; a secondary buoyant float slide retained by the overflow tube, having a latch member coupled thereto and connected to the flush lever, passing through the aperture of the latching plate; and a shoe rod coupled to said secondary buoyant float to push the stopper when it is discharging a first volume of water to flush liquids from the toilet bowl. For flushing solids, the flush lever is operated to a first intermediate position, lifting only the stopper causing a total flush of water because the latch member is latched by the tilting gate of the latch plate and the buoyant float as well as the shoe rod remain inoperative.

Abstract: A refilling preventing system for a toilet tank, to prevent refilling of the tank in case of a leak, comprising: a receptacle in the tank in which the buoyant float of the fill valve is placed; a water filling conduit to fill the receptacle after a flush discharge; a plug closing the overflow tube, to cause a momentary vacuum at a flush conduit of the toilet bowl connected to the discharge opening of the toilet tank after a flush discharge and when the stopper is at a closing position; and a siphon conduit, operable by a lever mechanism, which is connected to the discharge opening and to said receptacle, that allows to flush the receptacle, after a flush discharge, by a siphon effect created by the vacuum at the flush conduit of the bowl. In case of a leak emptying the tank, the receptacle will remain filled and the buoyant float will be at its closing position impeding the fill valve to refill of the tank.