Abstract:
An air cleaner including ozone removal is provided according to an embodiment of the invention. The air cleaner includes an air channel in the air cleaner, an air moving unit located in the air channel and configured to create an airflow, and an ozone decomposing element located in and extending substantially fully across the air channel. The ozone decomposing element causes decomposition of ozone in the airflow.

Description:
TECHNICAL FIELD 
     The present invention relates to an air cleaner, and more particularly, to an air cleaner including ozone removal. 
     BACKGROUND OF THE INVENTION 
     Air cleaners are widely used in home and office settings for cleaning the air. An air cleaner can filter the air in order to remove airborne contaminants. An air cleaner can therefore include any type of mechanical filter element comprising a mesh, a weave, a foam, etc. 
     In addition to filtering particles out of the air, an air cleaner can include an air ionizer (such as an electrostatic precipitator with a corona field or pre-ionizer element) that ionizes airflow passing through the air cleaner. The ionization transforms stable (O 2 ) molecules in the air into ozone molecules (O 3 ), where the ozone molecules are a by-product of the ionization process. Subsequently, the third oxygen atoms of the ozone molecules enter into destructive reactions with contaminants in the vicinity by oxidizing compounds they come into contact with. The oxidation can add oxygen molecules to these contacted compounds during the oxidation reaction. 
     Ozone is a powerful oxidizer because it is not a stable molecule. Ozone molecules spontaneously return to a stable, molecular state by releasing their third oxygen atoms. However, the spontaneous breakdown of ozone does not occur immediately, and substantial amounts of ozone can linger in the airstreams for some time. 
     One of the great advantages of ozone is that it is not selective in the reactions it initiates. It neutralizes; harmful volatile organic compounds (VOCs) by oxidizing them. Ozone destroys pathogens (microorganisms), either by reducing or destroying them or by cell lysing or oxidation. Another beneficial effect of ozone is that ozone treatment of the air can remove some troublesome odors. 
     However, the use of ozone for air cleaning has drawbacks. Being a highly unstable and reactive form of oxygen, the ozone also reacts with living matter. Moderate concentrations of ozone, such as levels above regulation limits (for example, limits suggested by Underwriters Laboratories Inc. (UL)), are known to cause headaches, nausea, and irritation of mucous membranes. Higher levels of ozone cause progressively more severe respiratory problems. As a result, ozone in higher concentrations can be troublesome to humans and animals. Consequently, ozone should desirably be removed from the air after generation. 
     Ozone removal filters are known. U.S. Pat. No. 6,375,905 to Moini et al. discloses an ozone removal filter that comprises an aluminum foil substrate that is impregnated with a catalyst. Air flows through the substrate, contacting the catalyst. The catalyst subsequently breaks down ozone in the airstream. The substrate of Moini comprises sandwiched sheets of aluminum foil. Each sheet receives a series of slits, with the sheet being subsequently stretched and twisted, wherein the slits are transformed into geometrically-shaped openings. Multiple such sheets are stacked together into a sandwich. The openings formed in one sheet do not align with the openings formed in adjacent sheets. Moini discloses that the airflow traveling through the substrate is forced to travel in a zig zag pattern (see FIGS. 6-7 and col. 8, lines 14-25). The assembled sandwich of multiple sheets can then be crimped or formed into a serpentine shape (see FIG. 8), allowing the final substrate to be shaped or formed. 
     SUMMARY OF THE INVENTION 
     An air cleaner including ozone removal is provided according to an embodiment of the invention. The air cleaner comprises an air channel in the air cleaner, an air moving unit located in the air channel and configured to create an airflow, and an ozone decomposing element located in and extending substantially fully across the air channel. The ozone decomposing element causes decomposition of ozone in the airflow. 
     An air cleaner including ozone removal is provided according to an embodiment of the invention. The air cleaner comprises an air channel in the air cleaner, an air moving unit located in the air channel and configured to create an airflow, and an ozone decomposing element located in the airflow. The ozone decomposing element comprises a substrate located in and extending substantially fully across the air channel and an ozone decomposing material formed on the substrate. The ozone decomposing element causes decomposition of ozone in the airflow. 
     An air cleaner including ozone removal is provided according to an embodiment of the invention. The air cleaner comprises an air channel in the air cleaner, an air moving unit located in the air channel and configured to create an airflow, and an ozone decomposing element located in the airflow. The ozone decomposing element comprises a ceramic paper matrix substrate and an ozone decomposing material formed on the substrate. The ozone decomposing element causes decomposition of ozone in the airflow. 
     An ozone removal method for an air cleaner is provided according to an embodiment of the invention. The method comprises providing an air channel in the air cleaner, providing an air moving unit located in the air channel and configured to create an airflow, and providing an ozone decomposing element located in and extending substantially fully across the airflow channel. The ozone decomposing element causes decomposition of ozone in the airflow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The same reference number represents the same element on all drawings. It should be noted that the drawings are not necessarily to scale. 
         FIG. 1  shows a tower air cleaner according to an embodiment of the invention. 
         FIG. 2  shows at least a portion of the internal components of the air cleaner according to an embodiment of the invention. 
         FIG. 3  shows an ozone decomposing element according to an embodiment of the invention. 
         FIG. 4  shows a cutaway view of a portion of the air cleaner according to an embodiment of the invention. 
         FIG. 5  shows a frame for the air cleaner according to an embodiment of the invention. 
         FIG. 6  shows an ozone frame lower portion according to an embodiment of the invention. 
         FIG. 7  shows an ozone frame upper portion according to an embodiment of the invention. 
         FIG. 8  shows an assembled ozone filter according to an embodiment of the invention. 
         FIG. 9  shows the air cleaner according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1-9  and the following descriptions depict specific embodiments to teach those skilled in the art how to make and use the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention. Those skilled in the art will also appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific embodiments described below, but only by the claims and their equivalents. 
       FIG. 1  shows a tower air cleaner  100  according to an embodiment of the invention. The air cleaner  100  includes a base portion  101  and a tower portion  102 . The tower portion  102  can be generally vertically positioned and elongate in shape. In one embodiment, the tower portion  102  can be substantially cylindrical in shape. The tower portion  102  includes a shell  103 , one or more doors  104 , and a control panel  110 . The tower portion  102  further includes an air inlet  105  and an air outlet  106 . Air is drawn in through the air inlet  105 , is cleaned inside the tower portion  102 , and the cleaned air is exhausted from the air outlet  106 . 
     The air inlet  105  is shown as being at the lower end of the tower portion  102 . However, it should be understood that alternatively the relative positions of the air inlet  105  and the air outlet  106  could be interchanged. 
       FIG. 2  shows at least a portion of the internal components of the air cleaner  100  according to an embodiment of the invention. The air cleaner  100  in this embodiment includes a substantially vertical air channel  200 , a motor  201  and corresponding impeller  202  located in the air channel  200 , an ozone decomposing element  205 , and an electrostatic precipitator  210 . The motor  201  and impeller  202  generate airflow through the air cleaner  100  (see arrows). The ozone decomposing element  205  can be located below the motor  201  and impeller  202 , as shown, or can be positioned above the motor  201  and impeller  202  and in the airflow. The ozone decomposing element  205  is located in and extends substantially fully across the air channel  200  and therefore the airflow passes through the electrostatic precipitator  210  and through the ozone decomposing element  205 . The ozone decomposing element  205 , because it extends fully across the air channel  200 , does not allow a portion of airflow to exit without scrubbing. After the ozone has reacted with contaminants in the airflow, the remaining or excess ozone is removed by the ozone decomposing element  205 . The ozone decomposing element  205  removes a significant amount of the ozone that is generated by the electrostatic precipitator  210 . The air cleaner  100  therefore provides the sterilizing and sanitizing benefits of ozone, but without the negative implications of human exposure to unacceptable levels of ozone. 
     The electrostatic precipitator  210  can comprise a source of ozone. The electrostatic precipitator  210  electrostatically charges dirt and debris particles in the airflow and then collects the charged particles on one or more collection plates. An electrostatic precipitator can produce relatively small amounts of ozone as a by-product. It is desirable to remove this ozone from the airflow of the air cleaner  100 . 
     The ozone decomposing element  205  decomposes ozone in the airflow. The ozone decomposing element  205  is located in and extends substantially fully across the airflow, wherein airflow leaving the electrostatic precipitator  210  must pass through the ozone decomposing element  205 . The ozone decomposing element  205  can comprise a plurality of air channels that are substantially aligned with the airflow. Because the ozone decomposing element  205  employs a catalytic reaction to scrub ozone, the ozone decomposing element  205  essentially comprises a lifetime ozone filter. 
     The air cleaner  100  can comprise a tower configuration, like that shown in  FIG. 1 , or can comprise any other configuration, such as substantially rectangular, substantially round, etc. The air cleaner  100  can comprise a floor air cleaner model, a table top air cleaner model, a portable or personal air cleaner model, etcetera (see also  FIG. 9 ). 
       FIG. 3  shows the ozone decomposing element  205  according to an embodiment of the invention. The ozone decomposing element  205  comprises a substrate  303  and an ozone decomposing material  304  formed on the substrate  303  (see insert). Alternatively, the ozone decomposing material  304  may be at least partially embedded in the substrate  303 . The substrate  303  can optionally include a frame (not shown) that supports the substrate and retains the ozone decomposing element  205  in the air cleaner  100 . 
     The substrate  303  includes a depth D. The depth D can be chosen according to various factors, including the available space in the air cleaner  100 , the velocity of the airflow, the desired back pressure or pressure drop across the ozone decomposing element  205 , the needed surface area of the substrate  303 , etc. 
     The substrate  303  comprises a plurality of substantially depth-wise air channels  305 . The air channels  305  in one embodiment are substantially continuous through the substrate  303 . The air channels  305  in one embodiment are substantially linear through the substrate  303 . The air channels  305  in one embodiment are substantially parallel to each other. Advantageously, the air channels  305  therefore present minimal obstruction to the airflow and as a result the ozone decomposing element  205  generates minimal back-pressure. The air channels  305  can be substantially co-linear and aligned with the airflow, as previously discussed. The air channels  305  can comprise a substantially honeycomb block, for example. Therefore, the substrate  303  can act as a flow straightener and can provide a substantially smooth and aligned airflow into the impeller  202 . 
     The air channels  305  can be formed in various ways, such as by crimping or forming, bonding, deposition or forming of fibers, aeration or heating of materials, stretching, etc. In the embodiment shown, the air channels  305  are substantially straight and the cross-sectional shape of an air channel  305  is substantially regular. Alternatively, the air channels  305  can be formed in irregular cross-sectional shapes and do not have to be co-linear and aligned with the airflow. 
     The air channels  305  can comprise any cross-sectional size. For example, where the air channels  305  are relatively large, the substrate  303  can comprise 80 cells per square inch, or less. Such a large cell size will result in a relatively low back pressure presented by the substrate  303 . In another example, where the air channels  305  are relatively small, the substrate  303  can comprise more than 80 cells per square inch, or more. Such a small cell size will result in a higher back pressure but will provide more reactive surface area and therefore more efficient ozone decomposition. However, it should be understood that the substrate  303  according to the invention beneficially provides a much lower back pressure than generated by typical foam or pleated style filters. 
     In the embodiment shown, the air channels  305  are formed by series of substantially serpentine sheets  308  interspersed with substantially planar divider sheets  309 . The sheets  308  and  309  can comprise any suitable materials. The substrate  303  can comprise any number of serpentine sheets  308  and planar divider sheets  309 , wherein the substrate  303  can be formed to a desired shape and size. However, it should be understood that the air channels  305  can include other cross-sectional shapes, including octagonal, hexagonal, circular, irregular, etc. 
     In one embodiment, the substrate  303  is formed of a metal matrix, such as an aluminum matrix, for example. The metal matrix allows some compression, wherein the metal matrix can accommodate some shaping. In another embodiment, the substrate  303  is formed of a ceramic/paper matrix. 
     The ozone decomposing material  304  interacts with and decomposes ozone that impinges on the ozone decomposing element  205 . Because the airflow must flow through the ozone decomposing element  205 , the ozone decomposition is substantially complete and uniform. 
     In one embodiment, the ozone decomposing material  304  comprises a metal oxide deposited on the substrate  303 . Ozone reacts with the metal oxide and decomposes. In one embodiment, the ozone decomposing material  304  comprises manganese oxide (MnO 2 ). However, it should be understood that the ozone decomposing material  304  can comprise any manner of suitable metal oxide. 
       FIG. 4  shows a cutaway view of a portion of the air cleaner  100  according to an embodiment of the invention. In this embodiment, the air cleaner  100  includes the motor  201 , the impeller  202 , and the ozone decomposing element  205 . In addition, in this embodiment the air cleaner  100  further includes a volatile organic chemical (VOC) filter  407  for removing volatile organic chemicals and/or odors from the airflow. The composition of the VOC filter  407  can be customized to target specific VOCs and/or specific odors. The motor  201 , the impeller  202 , the ozone decomposing element  205 , and the VOC filter  407  are located in an airflow channel  412 . 
     The VOC filter  407  is upstream of the ozone decomposing element  205  in the embodiment shown. However, it should be understood that the two components can be swapped. Together, the ozone decomposing element  205  and the VOC filter  407  remove a very high proportion of contaminants that can cause odors, irritation, or health problems. Alternatively, in another embodiment the ozone decomposing element  205  can further include a VOC removal/decomposing material, in addition to the ozone decomposing material. 
       FIG. 5  shows a frame  500  for the air cleaner  100  according to an embodiment of the invention. The frame  500  includes a VOC filter receptacle  503  and an ozone filter receptacle  506 . The VOC filter receptacle  503  receives the VOC filter  407 . The ozone filter receptacle  506  includes an ozone filter support ring  507 , wherein an ozone filter  220  (see  FIGS. 6-8 ) rests on the ozone filter support ring  507 . 
       FIG. 6  shows an ozone frame lower portion  230  according to an embodiment of the invention. The ozone frame lower portion  230  assembles to an ozone frame upper portion  250  in order to form an ozone filter  220  (see  FIG. 8 ). The ozone frame lower portion  230  includes at least one alignment rib  231 , one or more frame fastener projections  232 , at least one handling projection  234 , a plurality of bottom support members  237 , and a plurality of retention ribs  238 . The at least one alignment rib  231  can engage a feature of the frame  500  when inserted into the frame  500 . The one or more frame fastener projections  232  engage corresponding frame fastener apertures  252  in the ozone frame upper portion  250  (see  FIGS. 7-8 ). The at least one handling projection  234  can be grasped in order to insert and/or remove the assembled ozone filter  220 . In addition, the projection  234  can also serve to perform alignment during assembly so that the ozone filter  220  is not inserted upside down or backwards into the frame  500 . As a result, in one embodiment the projection  234  fits into a corresponding aperture in the frame  500 . The plurality of bottom support members  237  support a bottom surface of the ozone decomposing element  205 . The plurality of retention ribs  238  engage and exert a nominal amount of compression force on a side or sides of the ozone decomposing element  205 . The plurality of retention ribs  238  therefore firmly hold the ozone decomposing element  205  and prevent it from moving or rotating within the assembled ozone filter frame  222 . 
       FIG. 7  shows an ozone frame upper portion  250  according to an embodiment of the invention. The ozone frame upper portion  250  includes one or more frame fastener apertures  252 , at least one alignment notch  254 , and a plurality of top support members  257 . The one or more frame fastener apertures  252  receive the one or more frame fastener projections  232  of  FIG. 6 . The one or more frame fastener projections  232  can be received in the one or more frame fastener apertures  252  in a spring, friction, or snap fit, for example. The at least one alignment notch  254  receives at least a portion of the at least one alignment rib  231  of  FIG. 6 . The alignment rib  231  can fit into the alignment notch  254  and can guide the one or more frame fastener projections  232  into the one or more frame fastener apertures  252 . The plurality of top support members  257  retain the ozone decomposing element  205  within the assembled ozone filter frame  222 . 
       FIG. 8  shows an assembled ozone filter  220  according to an embodiment of the invention. The ozone frame lower portion  230  and the ozone frame upper portion  250  are assembled to form the ozone filter frame  222 . The ozone decomposing element  205  is held within the assembled ozone filter frame  222 . The air channels  305  in the ozone decomposing element  205  are substantially vertical in the figure. The ozone filter  220  can be positioned in the ozone filter receptacle  506  of  FIG. 5 , on the ozone filter support ring  507 . 
       FIG. 9  shows the air cleaner  100  according to an embodiment of the invention. The air cleaner  100  in this embodiment includes a substantially horizontal air channel  200  and a substantially horizontal airflow (see arrows). The impeller  202  in this embodiment comprises a squirrel cage fan  202  that pulls air through an optional pre-filter  911 , the electrostatic precipitator  210 , and through the ozone decomposing element  205 . In addition, the air cleaner  100  can include a VOC filter  407  (not shown) located before or after the ozone decomposing element  205 . 
     The air cleaner according the invention can be implemented according to any of the embodiments in order to obtain several advantages, if desired. The invention provides an air cleaner that uses ozone to kill living organisms in an airflow. The invention provides an air cleaner that uses ozone to neutralize airborne contaminants. The invention provides an air cleaner that uses ozone to remove odors from an airflow. The invention provides an air cleaner that removes ozone from an airflow.