Air purification devices
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 device including a reactor arranged to treat aerosol particulates carried in a fluid stream passing through the reactor, the reactor comprising:
a plasma chamber arranged to receive a fluid stream there through and to create a high concentration of reactive species within the fluid stream 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 positioned within the reactor downstream of the plasma chamber and downstream of the electrostatic filter and exposed to the fluid stream, 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 plasma chamber; 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.
2. An air purification device as recited in claim 1 wherein the absorptive material is carried on a porous block that is configured to receive the fluid stream there through.
3. An air purification device as recited in claim 1 wherein the absorptive material is applied as a coating to a component of a second electrostatic filter.
4. An air purification device as recited in claim 1 further comprising a prefilter that receives the fluid stream and filters at least some particles from the fluid stream.
5. An air purification device as recited in claim 1 further comprising:
an oxidation catalyst located downstream of the plasma chamber, the oxidation catalyst being arranged to produce more oxidation species within the reactor; and
a reduction catalyst located downstream of the oxidation catalyst and downstream of the absorptive material and configured to receive the fluid stream there through, wherein the reduction catalyst is arranged to significantly enhance the conversion of oxidation species that are contained in the fluid stream.
6. An air purification device as recited in claim 5 wherein the oxidation catalyst includes a material selected from the group consisting of Barium Titanium Oxide (BaTiO 3 ) and Titanium oxide (TiO 2 ).
7. An air purification device as recited in claim 1 wherein the plasma generator is a direct current plasma generator that creates a cold plasma in a plasma chamber.
8. 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.