REFLECTIVE LAMP TO MAXIMIZE LIGHT DELIVERY TO A PHOTOACTIVE CATALYST
BACKGROUND OF THE INVENTION
[1] The present invention relates generally to a reflective lamp utilized in a fluid
purification system that maximizes the light delivery to a photocatalytic coating that oxidizes gaseous contaminants that adsorb onto the surface to form carbon dioxide, water, and other substances.
[2] Indoor air can include trace amounts of contaminants, including carbon monoxide
and volatile organic compounds such as formaldehyde, tolucnc, propanal, butene, and acetaldehyde. Absorbent air fillers, such as activated carbon, have been employed to remove these Conants from the air. As air MOWS through the filter, the filter blocks the passage of the contaminants, allowing contaminant free air to flow from die filter. A drawback to employing filters is that they simply block the passage of contaminants and do not destroy them.
[3] Air purification systems commonly include one lamp or one bank of lamps and
one photocatalytic monolith, such as a honeycomb. A photocatalytic coating, such as titanium dioxide, is on the monolith. Titanium dioxide has been employed as a photocatalyst in a fluid purifier to destroy contaminants. When the titanium dioxide is illuminated with ultraviolet light, photons are absorbed by the titanium dioxide. promoting an electron from the valence band to the conduction band, thus producing a hole in the valence b;ind and adding an electron in the conduction band. The promoted electron reacts with oxygen, and the hole remaining in the valence band reacts with water, forming reactive hydroxyl radicals. When a contaminant adsorbs onto the titanium dioxide photocatalyst, the hydroxyl radicals attack and oxidize the contaminants to water, carbon dioxide, and other substances.
[4] If only one monolith and one lamp or one bank of lamps are employed in the air
purification system, much of the light from the lamp is misdirected and does not absorb onto the photocatalytic coating. Some of this misdirected light is reflected off a reflective surface applied on the housing of the air purification system and absorbed onto the photocatalytic coating, However, much of the light is still misdirected and not used for photocatalytic purposes. Therefore, the photocatalytic efficiency for the air purification system is less than optimum.
[5] A second monolith can be positioned on the side of the lamp opposite to the first
monolith to absorb the misdirected light. However, adding a second monolith is costly and light is still misdirected from the lamp and not used for photocatalylic purposes.

Reflectors can be added adjacent to the lamp or bank of lamps to direct more of the light
to the monolith, but this method adds an undesirable pressure drop to the system.
[6] Hence, there is a need for a reflective lamp utilized in a fluid purification system
that maximizes the light delivery to a photocatalytic coating.
SUMMARY OF THE INVENTION
[7] A reflective lamp utilized in a fluid purification system maximizes the light
delivery to a photocatalytic coating that oxidizes gaseous contaminants that adsorb onto the surface to form carbon dioxide, water, and other substances.
|/8j A fan draws a fluid, such as air, into a fluid purification system. The fr.:i;l flows
through an open passage or channel of a honeycomb. The surface of Ihc honcvcomb is
reflective with a titanium dioxide photocatalytic coating- An ultraviolet lie::; source
positioned proximate to the honeycomb activates '.he (iianimr. dioxide coaling. "I ;v \valls
of the fluid purification system a re preferably lined with u reflective material to reflect
the ultraviolet light onto the interior surface of the open passages of the honeycomb.
[91 The lamp includes a reflective surface. Preferably, the reflective surface is a
reflective coating. Preferably, the reflective surface is on at least half of the cross-sectional area of the lamp. The reflective surface can be on either the inner surface or the outer surface of the lamp.
[10] Light directed out of the non-reflective portion of the lamp travels towp.rds the
honeycomb and absorbs onto the photocatalytic coating. Light directed towards the reflective surface on the lamp is reflected off the surface of the reflective surface and passes through the non-reflective portion of the lamp to absorb onto the photocatalytic coating on the substrate. The reflective surface reflects light towards the honeycomb that would otherwise be misdirected away from the honeycomb, increasing photo-catalytic efficiency.
[11] When photons of the ultraviolet light arc absorbed by the titanium dioxide
coating, reactive hyclroxyl radicals are formed, When a contaminant, such as a volatile
organic compound, is adsorbed onto the titanium dioxide coating, the hydroxyl radical
attacks the contaminant, abstracting u hydrogen atom from the conltuninaiUand oxidizing
(he volatile organic compounds to water, carbon dioxide, and other substances,
[12J These and other features of the present invention will be best understood from the
following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
[13] The various features and advantages of the invention will become apparent to
those skilled in the art from the following detailed description of the currently preferred
embodiment. The drawings that accompany the detailed description can be briefly
described as follows:
[14] Figure 1 schematically illustrates an enclosed environment, such as a building,
vehicle or other structure, including an interior space and an HVAC system;
[15] Figure 2 schematically illustrates the fluid purification system of the present
invention;
[16] Figure 3 schematically illustrates the honeycomb of the fluid purification system:
[17] Figure 4 schematically illustrates a lamp having a reflective surface on an inner
surface of the lamp:
[18] Figure 5 .schematically illustrates a lamp having a reflective surface on ar. outer
surface of tlie lamp;
[19] Figure 6 schematically illustrates a lamp having a reflective surface on more than
one half of the surface of the lamp;
[20] Figure 7 schematically illustrates a lamp having a concave non-reflective surface;
and
[21] Figure 8 schematically illustrates a lamp used in a gennicidal system or a sysiem
to increase chemical reaction rates.
DETAILED DESCRTPTION OF THE PREFERRED EMBODIMENT
[22] Figure 1 schematically illustrates a building, vehicle, or other structure 10
including an interior space 12, such as a room, an office or a vehicle cabin, such as a car, train, bus or aircraft. An HA'AC system 14 heats or cools the interior space 12. Fluid in the interior space 12, such as air, is drawn by a path 16 into the HVAC system 14. The HVAC system 14 changes the temperature of the fluid drawn 16 from the interior space 12. If the HVAC system 14 is operating in a cooling mode, the fluid is cooled. Alternately, if the HVAC system 14 is operating in a heating mode, the fluid is heated. The fluid is then returned back by a path IS to the interior space 12, changing the temperature of the fluid in the interior space J2.
[23] Figure 2 schematically illustrates u fluid purification system 20 employed to
purify the fluid in the building or vehicle 10 by oxidizing contaminants, such us volatile organic compounds and semi-volatile organic compounds, to water, carbon dioxide, und other substances. Volatile organic compounds are organic compounds that have a
boiling point at 1 atmosphere of pressure of less than 200°C. The volatile organic compounds can be formaldehyde, toluene, prop anal, butanes, acetaldehyde, baldheadsketones, alcohols, aromatics, alkenes, or alkanes. .Sera-volatile organic compounds are organic compounds having a boiling point at 1 atmosphere of pressure of greater than 200°C. The semi-volatile organic compounds can be naphthalene, PCB's, PAIi's and insecticides. The fluid purification system 20 can purify the fluid before it is drawn along palh 16 into the HVAC system 14 or it can purify fluid leaving the HVAC' system 14 before it is blown along path IS into the interior space 12 of the building or vehicle 10. The fluid purification system 20 can also be a stand alone unit that is not employed with a HVAC system 14.
[24] A fan 3^ draws fluid into the fluid purification system 20 through an inlet 22.
Tiff fluid flows through :> particle filter 24 That fillers out dust or any other - panicky by blocking the flow of these particles. The fluid then flov/s through M monolith or substrate 28, such as n honeycomb. In one example, the honeycomb 28 is made of aluminum or an aluminum alloy. The substrate 28 is porous and allows fluid to ilo'.v through the substrate 28. Figure 3 schematically illustrates a front view. of the honeycomb 28 having a plurality of hexagonal open passages or channels 30. The surfaces of the piurality of open passages 30 are reflective with a photo catalytic coating 40. When activated by ultraviolet light, the coating 40 oxidises volatile organic compounds that adsorb onto the titanium dioxide coating 40. As explained below, as fluid flows through (he open passages 30 of the honeycomb 28, contaminants that are adsorbed on the surface of the titanium dioxide coating 40 are oxidized inio carbon dioxide, water and other substances.
[25] A light source 32 positioned proximate to the honeycomb 28 activates the
litanium dioxide pholocatalytic coating 40 on the surface of the open passages 30. Preferably, the liglu source 32 is an ultraviolet light source which generates light having ;i wavelength in Ihe range of i.80 nanometers to 400 nanometer,';. The light source 32 has a peak wavelength at 254 nni. The light source 32 can be a mercury vapor lamp, an excimer lamp, an electrodeless lamp, an inductively coupled lamp, a radio freiiusney powered lamp, or a li^li! emitting diode.
[26] The light source 32 is illuminated to activate the titanium dioxide coating 40 on
the surface of the honeycomb 28. When the photons of the ultraviolet light are absorbed by the titanium dioxide coating 40, an electron is promoted from the valence band to the conduction band, producing a hole in the valence band. The titanium dioxide coating 40 must be in the presence of oxygen and water to oxidize the contaminants into carbon
dioxide, water, and other substances. The electrons that are promoted to the conduction band are captured by the oxygen. The holes in the valence band react with water molecules adsorbed on (he titanium dioxide coating 40 to fonn reactive hydroxyl
radicals.
[27] When a contaminant is adsorbed onto the coating 40, the hydroxyl radical attacks
(lie contaminant, abstracting a hydrogen atom from the contaminant. In this method, the
hydroxyl radical oxidizes the contaminants and produces water, carbon dioxide, and
oilier substances. <
[28] Alter passing through the honeycombs 28, the purified fluid then exits :he fluid
purifier through an outlet 36. The walls 38 of the fluid purification system 20 are preferably lined wit!: a reflective material 42. The reflective material 42 reflects the ultraviolet light onto the surface of the open passages 30 of the honeycomb 2S.
[29] Figure 4 schematically illustrates a cross-sectional view of one lamp 44 of (he
light source 32. The light includes a reflective surface 46 on a portion of the lamp 44. 1'referably, !he reflective surface 46 is on at least half of the lamp 44. The reflective surface 46 can be on the inner surface 48 of the lamp 44 as shown in Figure 4 or the outer surface 50 of the lamp 44 as shown in Figure 5.
[30] Light 52 directed out of the non-rcllective portion 54 of the lamp 44 travels
towards the honeycomb 28 and absorbs onto (lie photocatalytic coating 40. Light 56 directed towards the. reflective surface 46 on the himp 44 is reflected off the surface of the reflective surface 46 and passes through the non-reflective portion 54 of the lamp 44 to absorb onto the photo catalytic coating 40 on the honeycomb 28. This light 56 is directed lo the honeycomb 28, rather than being directed away from he honeycomb 28, increasing the amount of light that absorbs on the pliolocalalytic coating 40.
[31 I If there was no reflective surface 46, the light 56 would be directed away from the
honeycomb 32 and would not be absorbed by the photocatalytic coating 40, decreasing the efficiency of the fluid purification system 20. By employing a reflective surface 46, light 56 that is originally directed away from the honeycomb 28 is directed buck to the honeycomb 28 for absorption.
32] Preferably, at least half of the lamp 44 is reflective with the reflective surface 46.
If half of the lamp 44 is reflective with the reflective surface 46, half the lamp 44 reflects light and prevents from ovine the lamp 44 in non-preferred directions. The other half the lamp 44 includes the non-reflective portion 54 that allows light to travel ::om the lamp 44 and be directed to the honeycomb 28.
[33] Preferably, the lamp 44 is cylindrical, and the reflective surface 46 is on the half
of lamp 44 that is the furthest away from the honeycomb 28. Although a lamp 44 having a cylindrical cross section is illustrated and described, it is to be understood that ihe lamp 44 can have any shape or size. The shape of the lamp 44 and the shape of the reflective surface 46 can be designed to maximize the amount of light delivered to the photocatalytic coating 40 on the honeycomb 28.
[34] Alternatively, as shown in Figure 6, more than half of the lamp 4-; can be
reflective with the reflective surface 46 to more specifically direct the light to the honeycomb 28. If more than half of the lamp 44 is reflective \vjth the reflective surface 48, less than half the lamp 44 includes an non-reflective portion 54. The area of the non-reflective portion 54 is smaller, allowing the light to be more accurately directsJ to tilt-honeycomb 2S.
[35] By employing a reflective, surface 46 on the lamp 44. more light is directed
towards the honeycomb 28, increasing the efficiency of the fluid purification system 20. Therefore, the fluid purification system 20 can be made smaller, providing a cost savings. Additionally, the size, power, and quantity of the lamps 44 can be reduced, also providing a cost savings.
[36] Alternately, the non-reflective portion 54 of the lamp 44 is shaped to provide
lending or refraction that directs the light 56 towards the honeycomb 2S. In one example,
as shown in Figure 7, the non-reflective portion 54 is a converging lens. That is, the non-
reflective portion 54 of the lamp 44 includes a thinner portion 60 closer to the reflective
surface 46 and a thicker potion 62 at a central point. By employing this shape, the lamp
44 can provide additional leasing or refraction to direct the light 56 to the honeycomb 28.
[37] Additionally, the position1 and the distance of the honeycomb 28 relative to the
lamp 44 can be adjusted to provide optimal light direction to the honeycomb 28.
[38] In addition to directing light to the honeycomb 28, the lamp 44 can also be
employed to direct light away from an unciesired location. For example, the ur.o'esired location can be material that would be damaged by the light from the lamp 44, people who can be harmed by the light 4-1 (such as eye or skin damage), or animals or other biological organisms that can be harmed by the light,
[39J Titanium dioxids is mi effective photocalalyst to oxide volatile organic
compounds to carbon dioxide, water and other substances. When a contaminant is adsorbed onto the titanium dioxide coating 40. the hydroxyl radical attacks the contaminant, abstracting a hydrogen atom from the contaminant. The hydroxyl radical oxidizes the contaminants and produces water, carbon dioxide, and other substances.
Preferably, the pliotocatalyst is titanium dioxide. In one example, die titanium dioxide is Millennium titania: Degussa P-25, or an equivalent titanium dioxide. However, it is to be understood that other photocatalytic materials or a combination of titanium dioxide \viih other metal oxides can be employed, as long as they are active supports for thenno-catalytic function. For example, the photocatalytic materials can be FeOj, ZnO, V205> SjiO;>, or FeTiOi. Additionally, other metal oxides can be mixed with titanium dioxide, such as I-'eOj, ZnO, V205, S nOi, CuO, MnOx, WO3, CojO.;, CeO2, Zr02, SiO2l A]203, Cr:O3, orNiO.
[41] The tilaniu:n dioxide can also be loaded with a metal oxide. In one example, the
melal oxide is WO;. ZnO, CdS, SrfiO.-,. Fc:03, V:0s, Sn02, FcTiO3, PbO, Co.:O4s NiO, CcO;, CuO, Si02, AXX .MnxO?, Cr20:,, orZvC)2.'
[42] Although a single honeycomb 28 has been illustrated and described, ii is to be
understood that nuLtipie honeycombs 28 can be employed. Additionally, although a honeycomb 28 ha- een iiiusiraied and described, i: is to be understood that th- litaninni dioxide coaling 40 c;m be applied on anv slmcuue. The voids in a honeycomb 28 are typically hexagonal in shape, bill it is to be u ncicrstood that o (her void shapes can be employed. As contaminants adsorb onto the titanium dioxide coating 40 of the structure in the presence of a light source, the contaminants are oxidized into water, carbon dioxide and other substances.
|43| Alternately, r.s shown in Figure S, the lamp 44 is employed in a germidical
system 64 and directs light towards an inidesirec biological entity 66. The biological entity can be bacterial, fungi, mold and viruses. In one example, the biological entity is suspended in a fluid, such as air. The fluid cat: move past the lam]) 44 or can be stationary. In another example, the biological emit}' is on the substrate 28. Again, the biological entity car: be suspended in a fluid, such as air. The fluid with the biological entity can move pasi liie lamp 44 or can be stationary. The substrate 28 can be a food preparation surface, an HVAC system, a fluid filter, n medical surface or a food preparation conveyor belt.
[44] As shown it: Figure 8, the lamp 44 can also be employed in a system 6- to direct
light towards a fluid or a surface to increase chemical reactions rates for chemical reactions that arc promoted by light without the presence of a catalyst. For example, the chemical reaction can cause tile iisslruciion of a material 66, such as odor’s. The chemical reactions can bo in a fluid, such as air. The fluid can be stationary or mobile. The chemical reaction can occur on a surface or a porous surface. For exarr.ple, the sin lace can be for t he display o finformauon. Alternately, the surface can be for the
transmission of light for information purposes. For example, the reactions can remove obscuring material from the surface.
[45] The foregoing description is only exemplary of the principles of the invention.
Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, so that one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described, For that reason the following claims should be studied to determine the true scope and content of this invention.

CLAIMS
What is claimed is:
1. A fluid purification system for purifying a fluid comprising:
a substrate; a photo catalytic. Coating applied on said substrate; and
a light source to activate said photo catalytic coating, said light source including a non-reflective portion that allows passage of light and a reflective portion that reflects said light to pass through said non-reflective portion of said light source.
2. The fluid purification system as recited in claim 1 wherein said light source-
activates said photocatalytic coating, and said photocatalytic coating oxidizes
contaminants that are adsorbed onto said photocataiytic coating when activated by said
light source.
3. The fluid purification system as recited in claim 1 wherein said light source is an
ultraviolet light source.
4. The fluid purification system as recited in claim 3 wherein said light, source is a
mercury vapor lamp.
5. The fluid purification .system as recited in claim 3 wherein said light source is an
exciter lamp.
6. The fluid purification system as recited in claim 3 wherein said light source is an electrode less lamp.
7. The fluid purification system as recited in claim 3 wherein said light source is an
inductively coupled lamp.
8. The fluid purification system as recited in claim 3 wherein said light source is a radio frequency powered lamp,
9. The fluid purification system as recited in claim 3 wherein said light source is a light emitting diode.

10. The fluid purification system as recited in claim 3 wherein said light source
generates said light having a wavelength between 180 nm and 400 nm.
11. The fluid purification system as recited in claim 10 wherein said light source has
a peak wavelength of 254 nm.
12. The fluid purification system as recited in claim 1 wherein said photocatalytic
coating is titanium oxide
13. The fluid purification system as recited in claim 1 wherein photons from said
light source are absorbed by said photocatalytic coating to form a reactive hydroxyl
radical that oxidizes contaminants in the presence of oxygen and water to water and
carbon dioxide.
14. The fluid purification system as recited in claim 1 wherein said contaminants are
a volatile organic compound including at least one of formaldehyde, toluene, prop anal,
butene, acetaldehyde, baldheaded, ketone. alcohol, aromatic, alkene, and alkane.
15. The fluid purification system as recited in claim 1 wherein said contaminants are
a semi-volatile organic compound including at least one of naphthalene, PCB, PAH and
an insecticide.
16. The fluid purification system as recited in claim 1 wherein said reflective portion
cover a. portion of said light source.
17. The fluid purification system as recited in claim 16 wherein said reflective
portion covers more than half of said portion of said light source.
18. The fluid purification system ns recited in claim 1 wherein said non-reflective portion of said lamp is proximate to said substrate and said reflective portion of said light source is distal to said substrate,
19. The fluid purification system as recited in claim 1 wherein said substrate is an array of voids separated by a solid.
20. The fluid purification system as recited in claim 1 further including a housing, the fluid purification system is in said housing, and walls of said housing are lined with a reflective material.
21. The fluid purification system as recited in claim 1 wherein said light source is
cylindrical.
22. The fluid purification system as recited in claim 1 wherein said reflective portion
is a reflective coating.
23. The fluid purification system as recited in claim 1 wherein said non-reflective
portion of said light source is shaped to direct said light to said substrate.
24. The fluid purification system as recited in claim 1 wherein said reflective portion
of said light source is shaped to direct said light to said substrate.
25. The fluid purification system as recited in claim 24 wherein said non-reflective
portion of said light source is shaped to direct said light to said substrate.
26. The fluid purification system as recited in claim 24 wherein said non-re:leclive
portion of said light source is a converging lens.
27. The fluid purification system as recited in claim 1 wherein said non-reflective
portion of said light source is a converging lens.
28. The fluid purification system as recited in claim 1 wherein the fluid is air.
29. The fluid purification system as recited in claim 1 wherein said substrate is
porous and allows a to flow through said substrate.
30. The fluid purification actual us recited in claim J wherein suicide light source
directs said light towards said subsonic and directs said light away from an undesired
location.
31. A fluid purification system for purifying a fluid comprising:
a substrate; a photocalalytic coating applied on said substrate; and
. a light source to activate said photocatalytic coating, said light source including a non-reflective portion that allows passage of light and a reflective portion that reflects said light to pass through said non-reflective portion and towards said substrate, arid said reflective portion reflects said light away from an imdesired location.
32. A germicidal system for destroying an undesired entity comprising:
the undesired biological entity; and a light .source including a non-reflective portion that passage and a reflective portion that reflects said light to pass through said non-reflective and towards the undesired entity.
33. The germicidal system as recited in claim 3 2 wherein the undesired biological
entity is one of bacteria, fungi, mold and viruses.
34. The germicidal system as recited in claim 3 2 wherein, the undesired biological
entity is suspended in a fluid.
35. The germicidal system as recited in claim 34 wherein said fluid is air.
36. The genitival system as recited in claim 34 wherein said fluid is in motior..
37. The germicidal system as recited in claim 34 wherein said fluid is stationary.
38. The germicidal system as recited in claim 32 further including a surface and the
biological enliry is on said surface.
39. The germicidal system as recited in claim 38 further including a photocatalytic
coaling applied on said surface, and said light source activates said photocatalytic
coating.
40. The germicidal system as recited in claim 38 wherein said surface is a food
preparation surface.
41. The germicidal system as recited in claim 38 wherein said surface is a fluid filter.
42. The germicidal system as recited in claim 38 wherein said surface is a medical
surface.
43. The germicidal system as recited in claim 38 wherein said surface is in motion.
44. A material purification system comprising: a substrate; a light source co increase a chemical reaction rate of a material on sain said 1 light source precluding a non-reflective portion that a Hows passage a reflective portion that reflects said light to pass through said non-reflective said light source.
45. The system as recited in claim 44 wherein said material is in a fluid.
46. The system as reciled in claim 45 wherein said fluid is air.
47. The system as recited in claim 45 wherein said material is suspended in said fluid.
48. The system as recited in claim 45 wherein said fluid is in motion.
49. The system as recited in claim 45 wherein said fluid is stationary.
50. The system as recited in claim 44 wherein said substrate transmits said light.
51. The system as recited in claim 44 wherein said substrate displays information.
52. The system as recited in claim 44 wherein said material is ozone.
53. The system a in canine 44 wherein saici substrate is porous.

54. A fluid purification system for purifying a fluid comprising: a container having an inlet and an outlet; a porous substrate inside said container; a device for drawing a fluid into said container through said inlet, flowing said fluid through said porous substrate, and expelling said fluid out of said container through said outlet; a photocatalytic coating applied on said substrate; and an ultraviolet light source to activate said photocatalytic costing, and photons from said ultraviolet light source are absorbed by said photocatalytic coating to form a reactive hydroxyl radical, and said reactive hydroxyl radical oxidizes contaminants in said fluid that are adsorbed onto said photocatalytic coating when activated by said light ultraviolet light source to water and carbon dioxide in the presence of water and oxygen, and said ultraviolet light source includes an non-reflective portion that allows passage of light and a reflective portion that reflects said light to pass through, said non-reflective portion of said light source.
55. A method of purifying a fluid comprising the steps of: providing a light source having an non-reflective portion and a reflective portion that covers at least half of a cross-sectional surface area of said light source; generating light that passes through said non-reflective portion of said light source and that reflects on said reflective portion of said light source and passes through said non-reflective portion of said light source; and
absorbing said light on a photocatalytic surface.