Abstract:
An ultraviolet ionizing unit for an air purifying that treats all air passing therethrough. The unit has a housing with an air ingress opening at first end, an air egress opening at a second end, an open end, at least two spaced apart internal retainers formed inside the housing, and a cavity formed in a space between the two spaced apart internal retainers. Two sections of ion generating material are retained in a spaced apart manner by the two spaced apart internal retainers. Spacers are used to hold a U-shaped UV lamp in the cavity, provide cushioning of the UV lamp therein, and providing additional sealing so that all air passing through the ionizing unit will be treated. A housing end cap covers the open end of the housing and retains the UV lamps therein so that the ion generating materials is fully exposed by UV light.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to air purifiers for cleaning air, and more particularly to an ultraviolet ionizing chamber for portable air purifiers, which ultraviolet ionizing chamber helps to eliminate contaminants from the air being treated, including biospecies, dust particles, odors, and volatile organic chemicals. 
     The presence of airborne biospecies (e.g., dust mites, bacteria, viruses, and fungi), dust particles, pollen, odors, and volatile organic chemicals can exacerbate allergies in people sensitive to these agents. Moreover, contaminated surfaces in hospitals and health care facilities—such as counter tops, beddings, bed pans, and medical devices—have been identified as the cause of spread of infections and disease. The Centers for Disease Control and Prevention (CDC) estimates 1.7 million hospital associated infections in the US every year, 99,000 out of those may result in death (Klevens and others 2007). Indoor air is also recognized as major vector of nosocomial infections, the infections that may be acquired in a hospital or health care facility. Methicillin resistant Staphylococcus aureus (MRSA), a type of  S. aureus  that is resistant to beta-lactams antibiotics, is a bacterium that causes infections of skin, and is identified as the common cause of health care associated infections (HAIs). CDC surveillance data reveals 58.4% MRSA infections were community-onset, 26.6% were hospital-onset, 13.7% were community-associated, while 1.3% were unclassified (Klevens and others 2007). 
     There is an ever growing need for development and evaluation of technologies aimed at reducing environmental contamination and improving the quality of indoor air that we breathe. Accordingly, a variety of devices and methods have used to purify air. These include air filtration, the use of charged plates, and UV light, among others. However, the efficacy of some of these devices can be limited due to their inability to remove nearly all of the airborne agents. 
     There accordingly remains a need for a highly effective device which will remove a very high percentage, e.g., 95%, and preferably 98% or more of these agents on a single pass of air through an air purification unit. 
     SUMMARY OF THE INVENTION 
     The invention is an ultraviolet ionizing chamber for portable air purifiers, which ultraviolet ionizing chamber helps to eliminate contaminants from the air being treated including airborne biospecies (e.g., dust mites, bacteria, viruses, and fungi), dust particles, pollen, odors, and volatile organic chemicals. 
     In one embodiment the invention provides an ultraviolet ionizing unit for an air purifying, the ultraviolet ionizing unit comprising: a housing having a top wall, an end wall, and a bottom wall, with an open front, an air ingress opening, an air egress opening, at least two spaced apart internal retainers formed inside the housing, and a cavity formed in a space between the two spaced apart internal retainers; two sections of ion generating material, one each retained by the two spaced apart internal retainers; a housing end cap that covers the open front of the housing and retains the two sections of ion generating material therein; a U-shaped UV light source with two generally parallel portions, a U-shaped portion joining the two generally parallel portions, and two ends with electrical leads, the U-shaped UV light source being positioned in the cavity; and spacers that hold the U-shaped UV light source in the cavity and provide cushioning of the UV light source therein. 
     In another embodiment the invention provides a: An ultraviolet ionizing unit for an air purifying, the ionizing unit comprising: a housing with an air ingress opening at first end, an air egress opening at a second end that is opposite the first end, and an open end, at least two spaced apart internal retainers formed inside the housing, and a cavity formed in a space between the two spaced apart internal retainers; two sections of ion generating material, one each retained in a spaced apart manner by each of the two spaced apart internal retainers; a housing end cap that covers the open end of the housing; a U-shaped UV light source with two generally parallel portions, a U-shaped portion joining the two generally parallel portions, and two ends with electrical leads, the U-shaped UV light source being positioned in the cavity; and spacers that hold the U-shaped UV light source in the cavity and provide cushioning of the UV light source therein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an exemplary ultraviolet ionizing chamber of the invention. 
         FIG. 2  is a rear perspective view thereof. 
         FIG. 3  is a top plan view of an exemplary section honeycomb material treated with titanium dioxide, which used in the ionizing chamber. 
         FIG. 4  is a top plan view of an exemplary UV light source of the invention. 
         FIG. 5  is a top plan view of an exemplary housing end cap. 
         FIG. 6  is a perspective view of an exemplary electronics housing/housing end cap unit. 
         FIG. 7  is front perspective view of an exemplary housing for the ionizing chamber, with other components removed. 
         FIG. 8  is a front perspective view of an exemplary housing for the ionizing chamber, with its light source electronics housing/housing end cap and a downstream section of honeycomb material in place, but with the upstream section of honeycomb material and the option front grill removed. 
         FIG. 9  is a cross-sectional view through view lines  9 - 9  of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Turning first to  FIGS. 1 and 2 , there are shown, respectively, front and rear perspective views of an exemplary ultraviolet ionizing chamber  10  of the invention. The ultraviolet ionizing chamber  10  has a housing  12  with a top wall  14 , an end wall  16 , a bottom wall  18 , and a front grill/mounting plate  20 . The front grill/mounting plate  20  has a grid opening  22  providing openings for air to enter the ionizing chamber  10 . The front grill/mounting plate  20  is at an air ingress side “I” of thereof. For ease of handling the ionizing chamber  10 , two finger grips  24  can be provided. The finger grips  24  can comprise two spaced apart rectangular ears that are bent outwardly from the front grill/mounting plate  20 . The front grill/mounting plate  20  has a rim  26  that provides a surface for attaching to an air purification system (not shown) and provide airtight sealing therewith, to ensure that all the air entering the air purification system must pass through the ultraviolet ionizing chamber  10  so that all air, rather than just a portion of the air, is treated. A power cord  28  from a light source electronics housing  30  passes through a hole  32  in the front grill/mounting plate  20 . A power connector  34  is on the end of the power cord  28 . The housing  12  has rear rim section  40 ,  42 , and  44  that extend from at or near back edges of the top wall  14 , the end wall  16 , and the bottom wall  18 , respectively. A housing end cap  46  carrying the light source electronics housing  30  is detachably connected to the housing  12 . A section of honeycomb material  50  is positioned at an air egress side ‘E” of the housing and can be seen through an egress window  52  defined by the housing end cap  46  and rear rim section  40 ,  42 , and  44 . 
       FIG. 3  is a top plan view of an exemplary section of honeycomb material  50  treated with titanium dioxide, which honeycomb material is used in the ionizing chamber. The honeycomb material can be a plastic material, with a grid of tubular sections  52  that are interconnected. In one embodiment, tubes have a diameter of about 4 mm is used. The honeycomb material can be of a desired thickness, and a thickness of about 14 mm functions well. The tubes  52  making up the honeycomb material  50  have passages therethrough. When installed in the housing  12  of the ionizing chamber, the axes of the tubes  52  will be aligned with the air flow and will generate positive and negative ions. This material will sometimes be referred to herein as ion generating material. 
     Such a material provides minimal interruption of airflow therethrough. As will be discussed further below, when the titanium dioxide is activated by the high intensity UV light emanating from the UV light source, e.g., a UV lamp (shown in  FIGS. 4 ,  6 , and  8 ), will generate positive and negative ions, which ions will almost instantaneously cause contaminants in the air being treated to clump together, and fall from the air. Furthermore, illumination of the titanium dioxide on the honeycomb material will likewise generate hydrogen peroxide, which is a powerful oxidizing agent to deactivate biospecies (e.g., dust mites, bacteria, viruses, and fungi), dust particles, pollen, odors, and volatile organic chemicals. The ratio of the length of the tube to the diameter of the tube should not be too large so that the entire surface of the titanium dioxide coated honeycomb material can be bathed in UV light. Although material having a honeycomb structure is one preferred type of material, other materials can be used if desired, such as webbed material having a number of strands coated with titanium dioxide (or other materials) that provide the ionizing effect when irradiated with UV light. An important consideration in selection of the material being that air flow not be overly impeded and that the titanium dioxide coating be adapted to be bathed with UV light. 
       FIG. 4  is a top plan view of an exemplary UV light source  60  of the invention. The UV light source  60  can preferably comprise a UV lamp with a U-shaped configuration, with two parallel elongate sections  62  and  64 , joined with a U-shaped end  66 . At the ends  68  and  70  of the elongate sections  62  and  64 , respectively, are pairs of electrical leads  72  and  74  for energizing filaments  76  in the tubing. An outline of the top wall  14 , end wall  16 , and bottom wall  18  of the housing  12  is shown. An outline of front spacer  80  and rear spacer  82  are shown. The spacers  80  and  82  can be formed of foam rubber or other material and help prevent shocks to the unit from damaging the UV light source  60 . A channel  84  can be cut in the front spacer  80  to hold the U-shaped  66  front end of the UV light source  60  and two slots  86  cut in the rear spacer  82  to suspend the ends of the elongate sections  62  and  64 . The spacers  80  and  82  also serve another purpose in that the impede airflow therethrough, forcing air that passes through the ultraviolet ionizing chamber  10  to be exposed to UV light from the UV light source  60 . As can be see, the distance R 1  from the two parallel elongate sections  62  and  64  to a centerline “CL” between the two sections, and the distance R 2  from the two parallel elongate sections  62  and  64  to the walls  14  and  18  are likewise minimized. 
       FIG. 5  is a top plan view of an exemplary housing end cap  46 . It includes a plate  46  and two apertures  90  for passage of the pairs of electrical leads  72  and  74  (not shown.) The plate  46  also can have apertures  92 , the purposes of which is to retain complementary tab (not shown) on the light source electronics housing  30  to hold it in place to the housing end cap  46 . Rectangular ears  94  formed by cutouts in the plate  46  are provided to engage and interlock with slots formed on the housing, as described below. 
       FIG. 6  is a perspective view of an exemplary electronics housing/housing end cap unit  100 . The light source electronics housing  30  is shown attached to the exemplary housing end cap  46  with its power cord  28  extending therefrom. The UV light source  60  is connected to the electronics housing/housing end cap unit  100  and during assembly of the ionizing chamber  10 , the UV light source  60  and its connected electronics housing/housing end cap unit  100  will be engaged with the housing, as shown in  FIG. 8 . 
       FIG. 7  is front perspective view of an exemplary housing  12  for the ionizing chamber  10 , with other components removed. The extending inwardly from the top wall  14 , end wall  16 , and bottom wall  18  are pairs of spaced apart retention rails  102  and  104 . The each of the retention rails in the pairs of retention rails  102  and  104  are spaced apart by a distance D that is approximately the same as the thickness of the sections of honeycomb material so that when the sections of honeycomb material are engaged in the housing  12 , any air passing through the ultraviolet ionizing chamber  10  will be forced to travel through the sections of honeycomb material. The pairs of spaced apart retention rails  102  and  104  establish retainers, or slots “S”, for receipt of the sections of honeycomb material. The two pairs of retention rails  102  and  104  in turn spaced apart by distance C, which defines a cavity into which the UV light source will be located. While such retention rails  102  and  104  are shown on the top wall  14 , end wall  16 , and bottom wall  18 , due to the presence of the front spacer  80  (see  FIGS. 4 and 8 ) which will tend to prevent leakage of air at the end wall  16 , the use of retention rails on the end wall  16  is optional. The ingress end “I” and egress end “E” are shown. Rim portions  106 ,  108 , and  110  extend from the top wall  14 , end wall  16 , and bottom wall  18 , respectively, and are formed at an ingress end I of the housing  12 . This provides a surface for attachment of the front grill/mounting plate  20 . Located around terminal ends of the rim portions  106 ,  108 , and  110  is a front groove  120 . Located around terminal ends of the rear rim sections  40 ,  42 , and  44  is a rear grove  122 . The front and rear grooves  120  and  122  provide openings into which rectangular ears  94  formed by cutouts in the housing end cap  46  (see  FIG. 5 ) engage. The housing  12  can conveniently be formed of extruded material (e.g., aluminum, plastic, etc.) having the described profile. This arrangement of the wall sections  14 ,  16 , and  18  provides a housing into which the sections of honeycomb material can easily be slid into during assembly, and with the UV bulb and its connected electronics housing/housing end cap unit  100  engaged therewith. 
       FIG. 8  is a front perspective view showing an ingress opening in the exemplary housing for the ionizing chamber  12 , with its light source holder/housing end cap  100  (having end cap  46  and light source electronic housing  30 ) and a downstream section of honeycomb material  50  in place, but with the upstream section of honeycomb material and the option front grill removed. The rim portion  106 ,  108 , and  110  extending from wall  14 ,  16 ,  18 , respectively, are shown. Also shown are UV light source  60 , and spacers  80  and  82 . 
       FIG. 9  is a cross-sectional view of the assembled ultraviolet ionizing chamber  10  (less the front grill/mounting plate) through view lines  9 - 9  of  FIG. 1 . As can be seen, the sections of honeycomb material  50 A and  50 B are snuggly positioned in the housing  12  within the pairs of retention rails  102  and  104 , respectively. The U-shaped UV light source  60  with its two parallel sections  62  and  64  will provide for generally uniform bathing of the two section of honeycomb material  50  with UV light, and will force the air that passes through ingress end “I”, through the first section of honeycomb material  50 A, pass through the cavity C with the UV bulb  60 , then through the second section of honeycomb material  50 B and out the egress end E through the egress window  52 . The unique construction of the housing  12  which tightly carries the two sections of honeycomb material and the positions the UV bulb  60  provides for full treatment of air passing through the ultraviolet ionizing chamber  10  and reduces airborne contaminants by 98% or more in a single pass. In operation, air will pass through the ultraviolet ionizing chamber  10  many times a day and substantially all airborne contaminants will be eliminated. Moreover, the electronics housing/housing end cap unit  100  which carries the U-shaped bulb  60  provides ease of assembly. 
     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.