Patent ID: 7547420

Claim:
Air purification device for reducing pollutants in the air, comprising: an ionizer, which is exposed to an air flow; a driver stage operably connected to the ionizer to provide ionization power for ionizing the air supplied by the air flow; a gas sensor for measuring pollutant concentration and indicating a measured pollutant concentration by an output signal; a controller operably connected to the driver stage and the gas sensor; the driver stage, the ionizer, the gas sensor and the controller form a closed loop control circuit such that in case of a variation in the pollutant concentration in the air supplied by the air flow the output signal of the gas sensor may be returned to a predetermined desired value; and the gas sensor being arranged a predetermined distance with respect to the ionizer to maintain a sufficient feedback between the ionizer and the gas sensor, the predetermined distance is such that, in an open loop control circuit, a variation in the output signal of the gas sensor owing to a precipitous variation in the pollutant concentration in the air supplied by the air flow may be compensated by a variation in the ionization power such that the output signal of the gas sensor may be returned to its predetermined desired value.