Patent EP-2090325-A2 (EP)
Inventor: CHURKIN ANDREY ANDREEVICH
IPC: A61L9/22
Filed: 2007-10-30
Abstract: A method and device are related to air treatment and purification, and more particularly to air and aerosol disinfection by inactivating and destroying bacteria, fungi and viruses including of avian flu H5N1 virus during one passage of the air and aerosol flow through inlet system of ventilation before blowing disinfected air and aerosol into premises of residential, commercial and industrial buildings. 
     A method for disinfecting air using negative ions of oxygen comprising the steps of (a) blowing the air through the ventilation system, (b) exposing the air to the flow of alpha particles, (c) reducing positive ions contained in the air to neutral molecules at the surface of an electrode having negative electric potential, (d) simultaneously decreasing the energy of free electrons contained in the air to the range of 0.4 to 2.0 eV through effect of electric field that is parallel to the air flow, (e) providing high concentration of negative ions of oxygen for at least 4 to 36 seconds during which time bacteria, fungi and viruses including avian flu virus contained in the air and aerosol are inactivated and destroyed, (f) reducing concentration of negative ions of oxygen to the range of 600 to 50000 sm -3  with a unipolarity coefficient, that is number of positive ions of oxygen divided by number of negative ions of oxygen, approximating 0 at the surface of the electrodes having positive electric charge before blowing disinfected air and aerosol into the premises. 
     A device for disinfecting air using negative ions of oxygen is presented that consists of serially connected air inlet duct of ventilation system, ionization chamber, disinfection chamber, air outlet, whereas in one of the embodiments the disinfection chamber is divided into discharge duct connected to the atmosphere and air distribution duct connected to air outlets through which disinfected air is blown into the premises. 
     Ionization chamber contains at least one source of alpha particles mounted on at least one plate. At least two electrodes are mounted across air flow after the plate at the back of ionization chamber. Ionization chamber and plates are made of a non-conducting material. Each electrode is made of a conducting mesh connected to negative terminal of direct voltage source, the positive terminal of which is earthed. Each plate has a depression in which sources of alpha particles are fixed provided depth of the depression is at least 2 mm greater than thickness of a source of alpha particles. The distance between the last source of alpha particles along the ionization chamber and the electrode nearest to it does not exceed 20 mm. Voltage on electrodes is maintained within the range of 0.2 to 10.0 kV depending on the size of cells of the mesh. 
     Disinfection chamber is a part of the ventilation duct where air has a high concentration of negative ions of oxygen. The length of the disinfection chamber is a distance between the last electrode mounted at the back of ionization chamber and the nearest electrode mounted in outlet duct used to distribute disinfected air into premises. This length  L  is no less than  L ≥ TV,  where  V  - mean linear velocity of air flow in the disinfection chamber and time  T  is  5.0 ≤ T ≤ 36.0 s. 
     In one of the embodiments of the device the disinfection chamber, being part of the ventilation air duct, is divided into two branches: distribution and discharge ducts. At least one electrode is mounted in the outlet duct. The electrode is made of a conducting mesh connected to a positive terminal of direct voltage source, the negative terminal of which is earthed. The voltage on the electrode is 1.0 to 10.0 kV. 
     The discharge duct has an electrode installed at its entry. The electrode is made of a mesh mounted across the air flow. It is connected to the negative terminal of direct voltage source, whereas positive terminal of it is earthed. The voltage on the electrode is 1-10 kV depending on dimensions of cells of the mesh.