Abstract:
A photo-catalytic cell may produce bactericidal molecules in air by passing air across catalyst coated targets. Ultraviolet (UV) energy may be emitted from a source. A first portion of the UV energy from the source may be applied directly onto the targets. A second portion of the UV energy from the source may be reflected onto the targets.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims is a continuation of U.S. patent application Ser. No. 14/065,031 filed on Oct. 28, 2013, which is a continuation of co-pending U.S. patent application Ser. No. 13/115,546 filed on May 25, 2011, and claims the benefit of U.S. Provisional Patent Application No. 61/380,462 filed on Sep. 7, 2010, all of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention generally relates to methods and apparatus for producing an enhanced ionized cloud of bactericidal molecules. 
         [0003]    Photo-catalytic cells may be employed to produce bactericidal molecules in air flow passing through the cells. The cells may be positioned to ionize air that may then be directed into an enclosed space or room. Emerging molecules from the cells may have a bactericidal effect on various bacteria, molds or viruses which may be airborne in the room or may be on surfaces of walls or objects in the room. 
         [0004]    Typically, such cells may be constructed with a “target material” (or coated surface(s) surrounding a broad spectrum ultraviolet (UV) emitter. This combination can produce an ionized cloud of bactericidal molecules. The target may be coated with titanium dioxide as well as a few other proprietary trace elements. As air passes through or onto the target, UV energy striking the titanium dioxide may result in a catalytic reaction that may produce the desired cloud of bactericidal molecules within the airflow. These molecules, upon contact with any bacteria, mold or virus, may kill them. 
         [0005]    Effectiveness of such photo-catalytic cells may be dependent on the concentration of the bactericidal molecules which may be produced by the cells. The bactericide concentration level may be dependent on the degree to which UV energy is applied to the titanium dioxide of the honeycomb mesh. 
         [0006]    As can be seen, there is a need for a system in which a higher proportion of UV energy from a UV emitter (in such a photo-catalytic cell) can be caused to impinge upon the titanium dioxide within the cell. 
       SUMMARY OF THE INVENTION 
       [0007]    In one aspect of the present invention, a photo-catalytic cell with an ultraviolet (UV) emitter and catalyst-coated targets may be comprised of at least one UV reflector configured to reflect UV energy from the UV emitter onto the targets. The rectangular “honeycomb matrix” target shape shown in the attached  FIGS. 1,2 and 3  is just one of many mechanical shapes that could use the proposed “enhanced ionization” technology proposed in this application. The proposed enhancement technology consist of reflective surfaces that have the unique reflective specifications as described in paragraphs  21  thru  26 . 
         [0008]    In another aspect of the present invention, a method for producing bactericidal molecules in air may comprise the steps of: passing air across catalyst coated targets; emitting UV energy from a source; applying a first portion of the UV energy from the source directly onto the targets; and reflecting a second portion of the UV energy from the source onto the targets. 
         [0009]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of a typical photo-catalytic cell in accordance with an embodiment of the invention in which a typical “honeycomb matrix” is shown as the “target”; 
           [0011]      FIG. 2  is a side elevation view of the photo-catalytic cell of  FIG. 1 ; 
           [0012]      FIG. 3  is a cross sectional view of the photo-catalytic cell of  FIG. 2  taken along the line  3 - 3 ; and 
           [0013]      FIG. 4  is a comparison graph showing a difference in performance of the photo-catalytic cell of  FIG. 1  with and without use of UV reflectors in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
         [0015]    Various inventive features are described below that can each be used independently of one another or in combination with other features. 
         [0016]    Broadly, embodiments of the present invention generally provide photo-catalytic cells in which reflectors may be positioned to reflect UV energy and increase a proportion of emitted UV energy that strikes titanium dioxide in the cell at high incident angles. 
         [0017]    Referring now to the Figures, it may be seen that an exemplary embodiment of a photo-catalytic cell  10  may comprise an electronics box  12 ; a light pipe indicator  14 ; a power cord  16 ; a chamber  18 ; honeycomb targets  20 ; UV reflectors  22 - 1 ,  22 - 2  and  22 - 3 ; and a UV emitter or lamp  24 . The honeycomb targets  20  may be coated with titanium dioxide. 
         [0018]    In operation, air may pass across the honeycomb targets  20  while UV energy may be applied to the target  20  by the lamp  24 . A photo-catalytic reaction may take place in the presence of the UV energy. The reaction may produce bactericidal molecules in the air. 
         [0019]    Referring now particularly to  FIG. 3 , the efficacy of the UV reflectors  22 - 1  may be illustrated. If the reflector  22 - 1  were not present, an emitted ray  26  might pass through the honeycomb target  20  without impinging on the titanium dioxide. However, when one of the reflectors  22 - 1  is present, an illustrative emitted ray  28 - 1  of UV energy may impinge on the UV reflectors  22 - 1 . The ray  28 - 1  may be reflected to become a reflected ray  28 - 2 . It may be seen that the reflected ray  28 - 2  may impinge on a surface of the honeycomb target  20 . It may be seen that a hypothetical unreflected ray  26 , which might follow a path parallel to that of the ray  28 - 1 , might pass through the honeycomb target  20  without impinging on the target  20 . Thus, presence of the reflector  22 - 1  in the path of the ray  28 - 1  may result in avoidance of loss of the UV energy from the ray  28 - 1 . The reflectors  22 - 1  may be relatively small as compared to the size of the honeycomb target  20 . The small size (about 10% of the size of the target  20 ) may allow for minimal air flow obstruction. In spite of their relatively small size, the reflectors  22 - 1  may be effective because they may reflect virtually all of the (normally lost) UV energy that is emitted in a direction that is almost orthogonal (i.e., within ±5° of orthogonality) to the outer vertical plane of the honeycomb target  20 . Hence, UV energy would pass thru the honeycomb target without touching the TiO2 surface. But by “reflecting” the UV rays onto the “opposite side” target matrix—that energy could be captured and utilized so as to add to the total ion count within the desired cloud of ionized molecules. In other words, the number of ions created by any incoming UV ray is proportional to the sine of the incident angle (Theta) between the UV ray path and the TiO2 surface that a given ray is impacting.
       At theta=90 deg Sine (90)=1 Maximum energy gathered   At theta=0 deg Sine (0)=0 Minimum energy gathered       
 
         [0022]    Reflectors  22 - 3  may be interposed between the lamp  24  and walls of the chamber  18 . UV energy striking the reflectors  22 - 3  may be reflected onto the honeycomb target  20 . Thus presence of the reflectors  22 - 3  may result in avoidance of loss of UV energy that might otherwise be absorbed or diffused by walls of the chamber  18 . Similarly, reflectors  22 - 2  may be placed in corners of the chamber  18  to reflect UV energy onto the honeycomb target  20 . 
         [0023]    The reflectors  22 - 1 ,  22 - 2  and/or  22 - 3  may be constructed from material that is effective for reflection of energy with a wavelength in the UV range (i.e., about 184 nanometers [nm] to about 255 nm). While soft metals such as gold and silver surfaces may be effective reflectors for visible light, their large grain size may make them less suitable than metallic surfaces with a small grain size (i.e., hard metals). Thus, hard metals such as chromium and stainless steel and other metals that do not readily oxidize may be effective UV reflectors and may be particularly effective for use as UV reflectors in the photo-catalytic cell  10 . Material with a UV reflectivity of about 90% or higher may be suitable for use in the reflectors  22 - 1 ,  22 - 1  and  22 - 3 . Lower reflectively produces lower effectiveness. To achieve the level of reflection required, it may be necessary to “micro-polish or buff” a selected materials reflective surface to achieve the specifications defined in para 22]-24] below. 
         [0024]    Advantageously, reflecting surfaces of the reflectors  22  should be electrically conductive. Specifically, outer surface coatings (added for oxidation protection) like glass, clear plastics, clear anodization (i.e. non-conductive) may diminish (considerably) any performance enhancement of the photo-catalytic cell  10 . 
         [0025]    Also it is important that reflecting surfaces of the UV reflector  22  produce surface specular reflection. (Specular reflection being a “mirror-like reflection” of light—in which a single incoming light ray is reflected into a single outgoing direction) Specular reflection is distinct from “diffuse” reflection where an incoming light ray is reflected into a broad range of directions. Diffuse reflection may diminish performance enhancement of the photo-catalytic cell  10 . 
         [0026]    In an exemplary embodiment of the photo-catalytic cell  10 , the reflectors  22 - 1 ,  22 - 2  and  22 - 3  may be chromium-plated plastic. Chromium-plated plastic may be a desirably low cost material with a desirably high degree of reflectivity for UV energy. So called “soft chrome” such as the plating used to produce a mirror-like finish that is seen on automobile chromed surfaces may be advantageously employed. 
         [0027]    It may be noted that there may be other cell shape designs which are not rectangular. For example, the cell  10  may be circular, tubular, or may have an otherwise complex shape. For these non-rectangular shaped cells, an optimum reflector design may be curved or otherwise non-flat in shape. 
         [0028]    It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.