US Patent 7415736 EcoBeta

A flush regulator for retrofit use in a toilet tank for regulating the outflow therefrom through an outlet, said regulator including a flap valve without buoyancy, said flap valve adapted to close said outlet, a rod connected at one end to said flap valve and a body of buoyancy at another end of said rod above said flap valve, said flap valve adapted to close said outlet when the water level in said tank reaches the upper edge of said body of buoyancy and said buoyancy and flap valve fall to close said outlet.