US Patent 7975324 Pressurized dual flush system

A dual flush volume pressurized flush device. A pressurized tank includes a tray for controllably retaining water during a flush event. The tray retains a certain volume of water when a reduced flush is activated, such that the entire volume of the tank is not flushed. In a full flush event, the activation causes substantially the entire volume of the tank to be flushed, including the volume of water inside the tray. A controllable water retention tray valve is positioned in the tray and provides a controllable release for the water in the tray.