Air purification devices

Abstract

An air purification reactor is described that has a variety of improvements. In one aspect, the air purification reactor includes an ionizer (or plasma chamber), an electrostatic filter, a photocatalyst, and a UV light source that is distinct from the ionizer. The ionizer is arranged to introduce ions into a gaseous fluid stream passing through the air purification device. The electrostatic filter is located downstream of the ionizer and is arranged to electrostatically filter particles from the fluid stream. The UV light source is positioned to subject the photocatalyst to ultraviolet light and may be arranged upstream, downstream, or intermediate the electrostatic filter. With this arrangement, the ultraviolet light that impinges on the photocatalyst causes a photocatalytic oxidative reaction to occur at the photocatalyst that is capable of reducing volatile organic compounds carried in the fluid stream. In other (separate) aspects, the reactor includes an absorber or an oxidation catalyst. Generally, the various aspects of the invention may be used separately or in combination with one another.

1 . An air purification reactor arranged to treat aerosol particulates carried in a fluid stream passing through the reactor, the reactor comprising:
 an ionizer arranged to ionize the fluid stream passing through the reactor to thereby electrically charge particulates and volatile organic compounds carried in the fluid stream;   an electrostatic filter located downstream of the plasma chamber for electrostatically filtering particles from the fluid stream; and   an absorptive material located downstream of the electrostatic filter, the absorptive material being arranged to absorb volatile organic compounds carried in the fluid stream and facilitate oxidation of the volatile organic compounds at least in part by exposing the absorbed volatile organic compounds to reactive species in the fluid stream that are generated by the ionizer; and   wherein the absorptive material is subjected to an electric field arranged to draw electrically charged volatile organic compounds towards the absorptive material to enhance the absorption of volatile organic compounds carried in the fluid stream.   
     
     
         2 . An air purification reactor as recited in  claim 1  further comprising an electrode located downstream of the electrostatic filter that is arranged to help subject the absorptive material to the electric field, wherein the absorptive material is coated on the electrode. 
     
     
         3 . An air purification reactor as recited in  claim 1  further comprising a pair of electrodes located downstream of the electrostatic filter that are arranged to help subject the absorptive material to the electric field. 
     
     
         4 . An air purification reactor as recited in  claim 2  wherein the electrostatic filter includes a dielectric and wherein the electrode is also arranged to help subject the dielectric to an electric field. 
     
     
         5 . An air purification reactor as recited in  claim 1  wherein the absorptive material is arranged on a porous structure configured to receive the fluid stream there through. 
     
     
         6 . An air purification reactor as recited in  claim 1  wherein the electric field that the absorptive material is subjected to is selected from the group consisting of an applied electric field and an induced electric field. 
     
     
         7 . An air purification reactor as recited in  claim 1  further comprising a catalyst located downstream of the absorptive material, the catalyst being arranged to significantly reduce the concentration of reactive species that are contained in the fluid stream before the fluid stream emerges from the reactor. 
     
     
         8 . An air purification device that includes the air purification reactor recited in  claim 1 . 
     
     
         9 . An air purification reactor as recited in  claim 1  further comprising:
 a photocatalyst exposed to the fluid stream; 
 a UV light source distinct from the ionizer that is arranged to subject the photocatalyst to ultraviolet light, whereby the ultraviolet light that impinges on the photocatalyst causes a photocatalytic oxidative reaction to occur at the photocatalyst that is capable of reducing volatile organic compounds carried in the fluid stream; and 
 at least one porous electrostatic filter located downstream of the ionizer for electrostatically filtering particles from the fluid stream. 
 
     
     
         10 . An air purification device as recited in  claim 9  wherein the photocatalyst includes titanium oxide (TiO 2 ). 
     
     
         11 . An air purification reactor as recited in  claim 1  further comprising a catalyst located downstream of the absorptive material, the catalyst being arranged to significantly reduce the concentration of reactive species that are contained in the fluid stream before the fluid stream emerges from the reactor. 
     
     
         12 . An air purification reactor arranged to treat aerosol particulates carried in a fluid stream passing through the reactor, the reactor comprising:
 an ionizer arranged to ionize the fluid stream passing through the reactor to generate reactive species in the fluid stream to thereby electrically charge volatile organic compounds carried in the fluid stream;   an absorptive material positioned within the reactor and exposed to the fluid stream, the absorptive material being arranged to absorb volatile organic compounds carried in the fluid stream and to expose the absorbed volatile organic compounds to reactive species in the fluid stream; and   at least one electrode arranged to subject the absorptive material to an electric field, wherein the electric field that the absorptive material is subjected to is selected from the group consisting of an applied electric field and an induced electric field and the electric field is arranged to draw electrically charged volatile organic compounds towards the absorptive material.   
     
     
         13 . An air purification reactor as recited in  claim 12  wherein the absorptive material is carried on a selected one of the electrodes, whereby during use a potential may be applied to the selected electrode to attract charged species towards the absorptive material. 
     
     
         14 . An air purification reactor as recited in  claim 12  wherein the absorptive material is sandwiched between a pair of electrodes that cooperate to generate the electric field. 
     
     
         15 . An air purification reactor as recited in  claim 12  wherein the absorptive material includes a magnesium silicate. 
     
     
         16 . An air purification reactor as recited in  claim 12  wherein the absorptive material includes a potassium permangante. 
     
     
         17 . An air purification reactor as recited in  claim 12  wherein the absorptive material is selected from the group consisting of zeolites, activated carbon and alumina. 
     
     
         18 . A reactor as recited in  claim 13  wherein the absorptive material electrode includes a metal frame that serves as the conductive electrode and the absorptive material is applied to the metal frame. 
     
     
         19 . A reactor as recited in  claim 18  wherein the metal frame has a honeycomb structure with sharp points. 
     
     
         20 . An air purification reactor as recited in  claim 12  further comprising an electrostatic filter located downstream of the ionizer and upstream of the absorber. 
     
     
         21 . An air purification reactor as recited in  claim 12  further comprising a catalyst located downstream of the absorptive material, the catalyst being arranged to significantly reduce the concentration of reactive species that are contained in the fluid stream before the fluid stream emerges from the reactor. 
     
     
         22 . An air purification reactor as recited in  claim 21  further comprising an electrostatic filter located downstream of the ionizer and upstream of the absorber.