US Patent 6928666 Toilet with self-contained ventilation system

A ventilation system is self contained on a toilet. The ventilation system has an enlarged vent pipe located in the water tank that communicates with the upper rim ducts of the toilet bowl. The vent pipe extends out of the water tank and reenters the toilet via the drain channel at a location downstream of the water trap. The vent pipe has a float valve in the water tank to prevent the tank from overflowing. A fan in the vent pipe exhausts the air from the toilet bowl; a flapper valve on the vent pipe end acts as a one-way valve preventing the flush from entering the exhaust duct.