Patent Publication Number: US-2020297890-A1

Title: Method of and unit for air treatment

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 15/871,719, filed Jan. 15, 2018. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to environmental air treatment and, more particularly, to a treatment unit that causes air to be disinfected by being exposed to UV light. The invention is further directed to a method of treating air. 
     Background Art 
     UV-C, also known as “germicidal ultraviolet” light, is known to deactivate molds, spores, and germs contained in tiny airborne droplet nuclei that transmit diseases such as measles, tuberculosis, and influenza from animal or human to animal or human. With significant intensity, UV-C can penetrate the cell wall of a microorganism and destroy it, but cannot penetrate the outer layer of a pet&#39;s or a human&#39;s skin or the cornea of the eye. 
     A multitude of systems have been devised to treat environmental air in which humans and pets reside. UV-C fixtures are currently available for disinfecting air as it is mechanically forced through ventilation ductwork and proximate to germicidal lamps, commonly referenced as “in-duct” UV-C fixtures. The radiation from the UV-C fixture neutralizes pathogens that would otherwise contaminate air as they are mixed and circulated/recirculated via one or more ventilation air ducts. A system fan moves contaminated air through ductwork, as an incident of which airborne pathogens are forced to pass proximate to and through a germicidal energy field generated by one or more UV-C lamps located in the air path/supply vent. 
     Specific pathogens can be targeted by applying published lethal UV-C energy doses to the air as it passes through the ductwork and the supply vent that distributes air to a space. These in-duct UV-C fixtures are commonly mounted in one of three locations: a) within the ductwork; b) in the air plenum proximate to HVAC cooling/heating coils; and/or c) at or inside the supply vent as the air exits the duct and is dispersed through a space. 
     In-duct air disinfection is achieved when air is mechanically forced through a ventilation system, past one or more UV-C lamps, and into a space through a supply vent. 
     Another form of system uses UV-C fixtures to disinfect air that naturally or mechanically rises upwardly within a room at a height above occupants&#39; heads. These fixtures are commonly mounted to upper walls or ceilings and project germicidal light outwardly in a generally horizontal path. This “upper-air” disinfection technology exploits the natural, passive movement of air within a space through the physical law of convection—hot air rising and cool air falling. 
     Any source of heat in a space accelerates convection rates. Upper-air fixtures employ UV-C lamps to generate light energy that is broadcast into a room at a specific height, typically at seven feet or more to be overhead standing room occupants. Light baffles or louvers cause the germicidal energy to be dispersed into the space in a tightly defined, narrow, energy band, known as an airborne pathogen “kill zone” of UV-C light energy. 
     In spaces with taller ceilings—typically 9+ feet—open fixtures can flood the upper part of the room while a shelf or lip prevent germicidal light from dispersing into the lower, occupied space in the room. These upper-air fixtures are often referenced as TB, or tuberculosis, lights, given their common use in countries with high occurrences of tuberculosis and other respiratory diseases. Fans may be used to accelerate and assist in increased air turn rates to increase the movement of contaminated air through the germicidal energy zone. Air disinfection is achieved only when air is moved, either mechanically or naturally, through the germicidal disinfection field created in the upper room space. 
     It is also known to disinfect air by forcing air through dedicated, defined disinfection chambers. These systems may be wall-mounted, hung from ceilings, or installed in conjunction with another type of system. This category of system pushes or pulls contaminated air through a fixed chamber, proximate to a UV-C germicidal lamp, and then causes the treated air to be distributed into a space. These systems are similar in structure and operate on the same basic principles as conventional floor air cleaners. Air disinfection is achieved only when air is mechanically pulled or pushed through the enclosed system, past a UV-C lamp, and then forced into a space. 
     Air destratification is practiced to be complementary to one or more of the above systems. Because cool air falls and warm air rises, stagnant air becomes stratified in confined spaces with warm air accumulating near the ceiling and cold air near the floor. Destratification technology uses one or more fans to accelerate the natural convection movement of contaminated air through a UV-C “kill zone”. If there is little or no heat source to generate sufficient convection currents, and no mechanical movement of stagnant air in a room, one or more fans may be used to move warm air from near the upper part of a room toward the floor, and conversely move cool air near the floor to the upper part of a room. The objective of the destratification is to eliminate hot/cold spots and create an environmental average of hot/cold air temperatures and to move air through the UV-C “kill zone”. Existing paddle-type ceiling fans are commonly used for purposes of destratification and air mixing to improve the efficiency of air disinfection technology. 
     The industry continues to seek improved systems that will more effectively deactivate molds, spores, and germs in spaces occupied by humans and pets, without causing user inconvenience or presenting any health hazard to humans, pets, or other animals. 
     SUMMARY OF THE INVENTION 
     In one form, the invention is directed to an air treatment unit having a frame and a source of UV light that is configured to disinfect air. The frame and UV light source are each configured to be mounted in an operative position so that operation of the UV light source causes UV light rays to disinfect air within a space. The frame is configured to define a primary treatment volume with an axis. The frame further includes an air guidance assembly. The air treatment unit is configured so that air within the primary treatment volume is guided by the frame in a radially outwardly moving pattern substantially fully around the axis. Air traveling in the radially outwardly moving pattern is exposed to light rays from the UV light source so that the air is disinfected. 
     In one form, the air treatment unit is provided in combination with an air moving assembly that is configured to induce flow of air from within the primary treatment volume in the radially outwardly moving pattern. 
     In one form, the air moving assembly is configured to cause air to be advanced axially relative to the frame into the primary treatment volume to induce flow of air from within the primary treatment volume in the radially outwardly moving pattern. 
     In one form, the air moving assembly is configured to direct air under pressure axially into the primary treatment volume. 
     In one form, the air moving assembly is configured to create a low pressure region that causes air to be advanced axially into the primary treatment volume. 
     In one form, the air moving assembly is configured to create a low pressure region that causes air to be advanced axially from the primary treatment volume. 
     In one form, the air moving assembly is maintained on the frame. 
     In one form, the air moving assembly is a fan. 
     In one form, the air moving assembly introduces air under pressure directly into the primary treatment volume. 
     In one form, the air moving assembly introduces air under pressure into a space at a location spaced from the frame, with the frame in the operative position. 
     In one form, the air moving assembly has a duct with an outlet from which pressurized air is expelled into the primary treatment volume. 
     In one form, the air moving assembly has a duct with an outlet from which pressurized air is expelled directly into a room in which the frame is placed in the operative position. 
     In one form, the air guidance assembly is configured to define at least one elongate opening through which disinfected air is communicated from the primary treatment volume in the radially outwardly moving pattern. 
     In one form, the source of UV light is radially spaced from and extends around the axis. 
     In one form, the air guidance assembly has a plurality of slats. The at least one elongate opening comprises a louver volume between at least first and second of the spaced slats. 
     In one form, the first and second spaced slats are in radially overlapping relationship. 
     In one form, the source of UV light is a plurality of UV lamps at spaced angular positions around the axis. 
     In one form, the plurality of UV lamps each is spaced from the axis. 
     In one form, the plurality of UV lamps are spaced and configured to produce a substantially uniform density of UV light rays within the primary treatment volume. 
     In one form, the frame has a square perimeter shape as viewed along the axis. 
     In one form, the invention is directed to an air treatment unit having a frame and a source of UV light that is configured to disinfect air. The frame and UV light source are each configured to be mounted in an operative position so that operation of the UV light source causes UV light rays to disinfect air within a space. The frame is configured to define a primary treatment volume with an axis. The frame further includes an air guidance assembly. The air treatment unit is configured so that air within the primary treatment volume is guided by the frame in a radially outwardly moving pattern. The air guidance assembly has a plurality of axially spaced slats including at least first and second slats between which a louver volume is defined. The air treatment unit is configured to create multiple zones at which air is treated differently by UV light rays from the UV light source. The multiple zones include: a) a first zone in the primary treatment volume; and b) a second zone in the louver volume. 
     In one form, the first and second slats each is spaced radially from the axis. 
     In one form, the UV light source is a UV lamp residing one of: a) within; and b) adjacent to, the primary treatment volume. 
     In one form, the first and second louvers are axially spaced. 
     In one form, the multiple zones further include a third zone that is radially outside of the first and second slats. 
     In one form, the guide assembly extends through at least 90° around the axis. 
     In one form, the guide assembly extends through at least 180° around the axis. 
     In one form, the guide assembly extends through at least 270°. 
     In one form, the guide assembly extends substantially fully around the axis. 
     In one form, the air guidance assembly has third and fourth slats in radially overlapping relationship with the first and second slats. There is a louver volume between the second and third slats and a louver volume between the third and fourth slats. A plurality of the louver volumes is exposed to UV light rays generated by the UV light source. 
     In one form, the UV light source is a UV lamp. At least a part of the UV lamp is spaced radially inwardly from the first, second, third, and fourth slats. 
     In one form, the louver volume is bounded by axially facing surfaces on the first and second slats. 
     In one form, the first, second, third, and fourth slats each is flat and resides in a respective plane. 
     In one form, wherein the planes of the first, second, third, and fourth slats are substantially parallel. 
     In one form, the planes of the first, second, third, and fourth slats are substantially orthogonal to the axis. 
     In one form, the UV light source is a plurality of UV lamps spaced around the axis at substantially the same axial location. 
     In one form, the UV light source is made up of at least four UV lamps spaced around the axis such that each of radial lines from the axis spaced at 90° passes through a different one of the four UV lamps. 
     In one form, the air treatment unit is provided in combination with an air moving assembly that is configured to induce flow of air from within the primary treatment volume in the radially outwardly moving pattern. 
     In one form, the air moving assembly is maintained on the frame. 
     In one form, the air moving assembly introduces air under pressure into a space, in which the frame is placed in the operative position, at a location spaced from the frame. 
     In one form, the invention is directed to a method of treating air in a space. The method includes the steps of: a) obtaining an air treatment unit having: a frame configured to define a primary treatment volume with an axis; and a source of UV light; b) placing the frame in an operative position relative to the space; and c) causing: i) air within the space to be moved into the primary treatment volume and become disinfected by being exposed to UV rays generated by the source of UV light; and ii) the disinfected air to be controllably guided through the frame in a radially outwardly moving pattern extending through at least 90° around the axis. 
     In one form, the frame has a plurality of slats including first and second slats between which a louver volume is defined. The disinfected air from within the primary treatment volume is guided radially through the louver volume and further disinfected by being exposed to UV rays generated by the UV light source within the louver volume. 
     In one form, the method further includes the step of causing air moved guidingly through the frame to be expelled from the louver volume and further disinfected by UV rays generated by the UV light source radially outside of the louver volume. 
     In one form, the step of causing air within the space to be moved into the primary treatment volume consists of causing air within the space to be moved axially relative to the primary treatment space. 
     In one form, the step of causing air within the space to be moved into the primary treatment volume consists of causing the air within the space to be moved radially relative to the primary treatment space. 
     In one form, the air treatment unit has a fan on the frame. The method includes the step of operating the fan to cause air within the space to be moved into the primary treatment volume. 
     In one form, the step of causing air within the space to be moved into the primary treatment volume involves causing air pressure to be generated through an outlet spaced from the frame. 
     In one form, the radially outwardly moving pattern extends through at least 180°. 
     In one form, the radially outwardly moving pattern extends through at least 270°. 
     In one form, the radially outwardly moving pattern extends substantially fully around the axis. 
     In one form, the first and second slats respectively have substantially flat first and second surfaces that radially overlap, face each other, and bound the louver volume. 
     In one form, the first and second surfaces are substantially parallel and orthogonal to the axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of one form of air treatment unit, according to the invention; 
         FIG. 2  is a schematic representation of a more specific form of air treatment unit as in  FIG. 1 ; 
         FIG. 3  is a schematic representation of an alternative form of air treatment unit as shown generically in  FIG. 1 ; 
         FIG. 4  is a side elevation view of one specific form of the inventive air treatment unit, as shown generically in  FIG. 1 , and in an operative state with respect to an existing duct which introduces treated air into a space; 
         FIG. 5  is a bottom view of the air treatment unit in  FIG. 4 ; 
         FIG. 6  is a view as in  FIG. 5  of a modified form of air treatment unit, according to the invention; 
         FIG. 7  is a side elevation view of the air treatment unit in  FIG. 6 ; 
         FIG. 8  is a side elevation view as in  FIG. 7  with the air treatment unit lowered with respect to a mounting wall; 
         FIG. 9  is a view as in  FIG. 8  with a bottom wall on the air treatment unit separated; 
         FIG. 10  is a view as in  FIG. 9  with the air treatment unit in an operative state; 
         FIG. 11  is a side elevation view of a further modified form of air treatment unit, according to the invention, in a preassembly position with respect to T-bar components on a drop ceiling; 
         FIG. 12  is a view as in  FIG. 11  with the air treatment unit in an operative state; 
         FIG. 13  is a view as in  FIG. 12  with a bottom wall of the air treatment unit separated; 
         FIG. 14  is a view as in  FIG. 13  with the wall reattached; 
         FIG. 15  is a side elevation view of a still further modified form of air treatment unit suspended in an operative state from a ceiling; 
         FIG. 16  is a schematic representation showing an axis for a primary treatment volume on the inventive air treatment unit and indicating an outwardly moving pattern of air from within the primary treatment volume; 
         FIG. 17  is a view similar to that in  FIG. 16  with the inventive air treatment unit adapted to operate at an inside corner location; 
         FIG. 18  is a view as in  FIG. 17  with the inventive air treatment unit adapted to operate at an outside corner; 
         FIG. 19  is a view as in  FIGS. 17 and 18  with the inventive air treatment unit adapted to operate at a straight vertical wall; 
         FIGS. 20-26  are schematic representations showing different contemplated configurations for the inventive air treatment unit in terms of how untreated air is delivered to the primary treatment volume and disinfected air is discharged from the air treatment unit; 
         FIG. 27  is a schematic representation of one layout of UV lamps on the inventive air treatment unit; 
         FIG. 28  is an enlarged, fragmentary, elevation view of a plurality of slats making up part of a frame on the inventive air treatment unit; 
         FIG. 29  is a schematic depiction showing a perimeter shape of a frame on the inventive air treatment unit taken along the axis of the primary treatment volume thereon; and 
         FIG. 30  is a flow diagram representation of a method of treating air in a space, according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In  FIG. 1 , an air treatment unit, according to the present invention, is shown in schematic form at  10 . The air treatment unit  10  is preferably configured to be attached to a wall  12 , which is most preferably a ceiling wall, but could be a peripheral side wall surrounding an occupiable space. 
     The air treatment system  10  has a frame  14  that is mounted to the wall  12 . The frame  14  supports a light source  16 , characterized herein as a “UV light source”, which is intended to encompass all different forms of light known to those skilled in the art capable of deactivating molds, spores, germs, etc., that are entrained in air, to thereby effect disinfecting of that air. 
     The frame  14  further supports an air moving assembly  18  that causes air within a space to be directed into a frame volume  20  that has UV rays from the source  16  therein capable of disinfecting air. 
     By mounting the frame  14  to the wall  12 , the frame  14  and UV light source  16  are maintained in an operative position within a space  22  in which air is to be disinfected. The air moving assembly  18  causes room air to be directed into the volume  20 , wherein it is treated by the UV light source and thereafter reintroduced to the space  22 . 
     The frame  14  is also configured to allow air expelled from a duct  24  on a forced air source  26  to be directed into the volume  20  for treatment by the UV rays from the light source  16 . 
       FIGS. 2 and 3  show alternative setups for the air treatment unit  10  within the space  22 . In these Figures, additional details of the air treatment unit  10  are also shown. 
     In  FIG. 2 , a primary treatment volume  28  is shown on the frame  14  with direct exposure to the operatively positioned UV light source  16 . In the primary treatment volume  28  there is an active germicidal energy field. An air guidance assembly  30  has at least one opening  32 , preferably with an elongate configuration, through which air from the primary treatment volume  28  passes to be distributed to the space  22  with the frame  14  operatively positioned on the wall  12 . Preferably, the opening(s)  32  has/have a louver arrangement wherein UV light from the source  16  creates a kill zone within the volume of the openings  32  wherein the air is further disinfected before dispersing into the space  22 . 
     Immediately outside of the frame  14  there exists a passive external germicidal energy field that treats the room air. That is, UV rays are directed through the louver volumes/openings  32  to the region immediately outside of the frame  14  and have sufficient intensity in this region to effect a significant level of passive treatment. 
     The air moving assembly  18  forces air from the space  22  into the primary treatment volume  28  to avoid room air stagnation. 
     The system  10  in  FIG. 3  has the same basic construction for the frame  14 , and similar components thereon, including the UV light source  16 , the primary treatment volume  28 , the air guidance assembly  30 , and the air moving assembly  18 . 
     Additionally, the frame  14  is configured so that the aforementioned duct  24  on the wall  12  forces air, typically conditioned through an HVAC system, directly into the primary treatment volume  28 . 
     When the forced air source  26  and air moving assembly  18  are operating at the same time, air from the duct  24  and air moving assembly  18  is caused to mix within the primary treatment volume  28 , wherein it is treated by the UV radiation from the source  16 . 
     The schematic representation of components in  FIGS. 1-3  is intended to encompass the components, as shown in specific embodiments described hereinbelow, and virtually an unlimited number of variations of those components and their interaction. The preferred embodiments described herein are exemplary in nature only and represent specific forms of the invention as generically defined in  FIGS. 1-3 . 
     One exemplary form of the air treatment unit  10  is shown in  FIGS. 4 and 5 . The frame  14  has a main frame portion  34  and a subframe portion  36 . 
     The subframe portion  34  is used to effect mounting of the frame  14  to the wall  12 . In this embodiment, the subframe portion  36  has a mounting portion  38  that spans between, and is supported upon, T-bar components  40  on a ceiling grid T-bar system so that with the frame  14  in the operative position of  FIG. 4 , the main frame portion  34  depends from the downwardly facing ceiling surface  42 . 
     In this embodiment, the length L and width W of the frame  14  are the same, with one preferred length and width dimension being 24 inches. Making the length L and width W the same is not a requirement, nor is a squared shape. Room geometry may dictate a different optimal shape. 
     The components in  FIGS. 4 and 5  are shown substantially to scale based upon the length and width L, W each being twenty four inches. The primary treatment volume  28  has a square shape as viewed along a vertical central axis  44 . The air guidance assembly  30  extends around and effectively frames the primary treatment volume  28 , as viewed from below in  FIG. 5 . 
     The air guidance assembly  30  consists of a series of slats  46 , each with a square frame shape. The slats  46  are mounted through a plurality of rods  48  depending from the subframe portion  36 . The slats  46  are flat, radially overlap, and are mounted in a close vertically spaced relationship to define louver volumes corresponding to the aforementioned elongate opening(s)  32 . The louvers/openings  32  define the aforementioned kill zone as air distributes radially outwardly relative the central axis  44  from the primary treatment volume  28  and funnels into the volume between the inner edges  50  of the slats  46  and the perimeter outer edges  52  thereof. This kill zone region is identified by the width dimension KZ in  FIG. 5 . Air is forced to travel controllably in a confined path and in a radial direction through the volume of the louvers/openings  32  over the distance KZ and, in its overall path within the treatment energy field, between the primary treatment volume  28  and a region of the space  22  outside of the primary treatment volume. 
     With this arrangement, air within the primary treatment volume  28  distributes through the louvers/openings  32  radially in a pattern substantially 360° around the central axis  44 . This flow pattern is identified generally by the arrows  54 . 
     Air flow into the primary treatment volume  28  in a downward direction is blocked by a bottom wall  56  on the frame  14 , which defines the lower boundary of the primary treatment volume  28 . 
     The bottom wall  56  supports the air moving assembly  18 , which is a conventional-type fan that draws air from the space  22  generally axially upwardly into the primary treatment volume  28 , as indicated by the arrows  58 . 
     The bottom wall  56  and air moving assembly  18  can be constructed to move as one piece and are supported together on hanging rods  60  depending from the subframe portion  36 . A wingnut  62  is shown for securing the bottom wall  56  on the bottom of one of the hanger rods  60  in the operative position of  FIG. 4 , wherein the bottom wall  56  blocks the primary treatment volume  28  and provides a decorative cover for the unit  10 , including over the downwardly facing surface  64  of the bottommost slat  46 . With this arrangement, by removing the wingnuts  62 , the bottom wall  56  and air moving assembly  18  thereon can be lowered to better access the air moving assembly  18  and to also access the primary treatment volume  28  and the plurality of lamps  66 , together making up the UV light source  16 . 
     In this embodiment, four lamps  66  are mounted to the frame  14  at equal distances from the central axis  44 . The lamps  66  are arranged at regular angular intervals around the axis  44 . In this embodiment, the lamps  66  cooperatively produce a square shape that is complementary to the shape of the primary treatment volume  28 . As viewed along the axis  44 , four radial lines spaced at 90° to each other are capable of passing, one each, through a different lamp  66 . As depicted, each lamp  66  includes a pair of bulbs  68 . Precise construction of the lamps  66  and their placement may vary considerably. One skilled in the art could readily come up with different arrangements to maximize exposure of air to the UV radiation generated by the lamps  66  within the primary treatment volume  28 , the kill zone region in the louvers/openings  32 , as well as in the passive treatment region outside of the frame  14 . 
     The ability to separate the bottom wall  56  facilitates placement and maintenance of the lamps  66 , as to change bulbs  68 , and also permits cleaning of the slats  46  which may accumulate dust over time which contrasts with the preferred black coloration of the exposed slat surfaces. 
     The subframe portion  36  is constructed so that the duct  24  can be connected thereto or positioned in relationship therewith, so that a discharge region  70  expels air from the forced air source  26  preferably downwardly, as indicated by the arrow  72 , directly into the primary treatment volume  28 . The forced air source  26  may be any type of structure that produces pressurized air and is typically one that delivers heated or cooled air under pressure to and through the duct  24  into the space  22 . 
     While not required, in the depicted embodiment, the central axis  44  coincides with the downwardly moving path of air from the duct  24  and the upwardly moving path of air generated by the air moving assembly/fan  18 . As depicted, the axis  44  is at the center of both paths, which are substantially parallel to each other. 
     The upwardly and downwardly directed air paths at least partially coincide so that air in the separate paths is caused to mix within the primary treatment volume  28  and is thereafter diverted in a non-vertical direction through the louvers/openings  32  into a region of the space outside of the primary treatment volume  28 . 
     Commonly, the air moving assembly  18  will be running constantly with the air treatment unit  10  in an “on” state. Thus, air is continuously drawn from the space  22  upwardly into the primary treatment volume  28 , exposed to the radiation field generated by the UV light source  16  therein, and further treated in the kill zone within the louvers/openings  32  from where it is dispersed back into the space  22 , and there passively treated in a region immediately outside of the frame  14 . 
     When the forced air source  26  is operated, the incoming flow of air from the duct  24  becomes exposed to the radiation within the primary treatment volume  28  as it is mixed with the flow generated by the air moving assembly/fan  18 . Thus, the incoming air is disinfected by the air treatment unit  10  as it is introduced into the space  22 . The pressure from the duct air causes a higher pressure distribution of air radially outwardly from the air treatment unit  10  relative to the axis  44 . 
     It should be understood that the invention also contemplates a more passive introduction of duct air as contemplated in the  FIG. 2  embodiment. 
     Further, the description of the structure in  FIGS. 4 and 5 , and others hereinbelow, relative to a ceiling mount is intended to be exemplary as one particular operative position for the air treatment unit  10 . The air treatment unit  10  could be mounted other than on a ceiling. Thus, the reference to vertical and horizontal should not be limited to a ceiling mount, and these references are arbitrary in the event that the air treatment unit is mounted in another orientation. For example, by changing the orientation of the air treatment unit  10 , the basic principles of operation are similar, even if not preferred. While the axis orientation may be changed to an extent to become horizontal, for purposes of simplicity in the claims and description herein, “vertical”, in characterizing the axis orientation, is an arbitrary reference that is not limited to any specific orientation. 
     Also, while not necessary, for purposes of uniformity of air treatment, the frame  24  is symmetrical on diametrically opposite sides of a reference plane containing the vertically extending axis  44 . In this embodiment, the frame is symmetrical about orthogonal reference planes RP 1 , RP 2  extending through the central axis  44 . 
     Some variations in the air treatment unit  10 , as described above, will now be described. Again, it is should be emphasized that these different versions are intended only to be exemplary in nature, showing other potential operating features and mounting options. 
     In  FIGS. 6 and 7 , a treatment unit  10 ′ is shown that is similar to the treatment unit  10  with a primary difference being that the subframe portion  36 ′ is modified from the subframe  36 . In this embodiment, the subframe portion  36 ′ has a squared housing  74  with an upper, outwardly projecting flange  76  that is supported on T-bar components  40  on a drop ceiling to maintain the frame  14 ′ in its operative position. 
     The lamps  66 ′ are mounted on a downwardly facing surface  78  on the housing  74  within a primary treatment volume  28 ′. The lamps  66 ′ are arranged so that the bulbs  68 ′ are in side-by-side relationship as opposed to in vertically spaced relationship, as shown for the bulbs  68  in  FIGS. 4 and 5 . 
     An air moving assembly/fan  18 ′ is mounted on a bottom wall  56 ′ to draw in room air in a direction of the arrows IA′, with treated air directed into the room space in a pattern indicated by the arrows OA′. 
     The air treatment unit  10 ′ otherwise generally functions in the same manner as the air treatment unit  10 , as described above. 
     The top wall  80  of the subframe portion  36 ′ may have an opening as large as a discharge opening on the duct  24 , or may simply allow passage of one or more wires  82  associated with electrical components  84  on the frame  14 ′ and required to operate the lamps  66 ′, air moving assembly/fan  18 ′, and any other electrical components. 
     A like, or identical, unit  10 ′ can be flush mounted to a surface  86 , as shown in  FIGS. 8-10 . Mounting may be effected with the bottom wall  56 ′ separated, as shown in  FIG. 9 , to facilitate access to a top wall  80  through the primary treatment volume  28 ′. This also facilitates the connection of the wires  82  within a junction box  88  on the wall  90  defining the mounting surface  86 . Conventional fasteners  92  can be used to secure the flange  76  against the surface  86  to maintain the unit  10 ′ in its operative position, as shown in  FIG. 10 . Air flow pattern is identical to that shown in  FIG. 7 , as indicated by the arrows IA′, OA′. 
     In  FIGS. 11-14 , a modified form of air treatment unit is shown at  10 ″, including sequence drawings showing how the same is installed with respect to ceiling T-bar components  40  on a drop ceiling. 
     The air treatment unit  10 ″ is substantially the same as the air treatment unit  10 ′, with the main difference being that the air moving assembly/fan  18 ″ is mounted to depend from a downwardly facing surface  94  on the bottom wall  56 ″. 
       FIG. 11  also shows the initial step for placing the air treatment unit  10 ″ in its operative position of  FIG. 14 . As shown, the entire air treatment unit is placed at an angle α to horizontal. In this orientation, a leading end  96  of the flange  76 ″ is situated so that it can be directed over a horizontal leg  98  on the T-bar component  40 . By then being shifted in the direction of the arrow  100 , the trailing end  102  of the flange  76 ″ can be tipped upwardly and will clear a leg  104  of the T-bar component  40  shown on the right side in  FIG. 11 . The entire air treatment unit  10 ″ can then be shifted to the right in  FIG. 11  so that the flange  76 ″ bridges, and is supported cooperatively by, the legs  98 ,  104 . 
     The wires  82  can be electrically connected at the junction box  88 . 
     By separating the wingnuts  62 ″, the bottom wall  56 ″ and air moving assembly/fan  18 ″ can be lowered as a unit, as shown in  FIG. 13 , to assist assembly, maintenance, cleaning, etc. 
     The bottom wall  56 ″ can then be re-secured to assume the  FIG. 14  state. 
     In  FIG. 15 , an air treatment unit is shown at  10 ′″ that is substantially the same as the air treatment unit  10 ′ with the exception that the frame  14 ″ has a plurality of mounting eyelets  106  fixed thereto. The eyelets  106  accommodate cables  108  which connect between the eyelets  106  and separate eyelets  110  fixed to a wall  112  at which the frame  14 ′″ is operatively positioned. The eyelets  106 ,  110  and cables  108  cooperatively make up a suspension assembly at  114  through which the frame  14 ″ is spaced from a downwardly facing surface  116  on a wall  118  with the frame  14 ″ operatively positioned. 
     Of course, virtually any type of a conventional structure might be used to make up the suspension assembly to establish the relationship between the air treatment unit  10 ′″ and the associated wall  118 . 
     Wires  82  can be extended from the frame  14 ″ to the junction box  88  to electrically connect operating components. 
     With all embodiments, the main frame portions and subframe portions may be configured to define spaces for electrical components and wiring needed to power the lamps, air moving assemblies, etc. It is not necessary to get into all of the details of the electrical components and their connection, as one skilled in the art would be able to readily devise different component arrangements to achieve the objectives set forth herein. 
     As noted above, the inventive air treatment unit can be used to replace a supply vent conventionally used to distribute air in an occupied space. Alternatively, a more passive interaction between the air treatment unit and an existing duct outlet is effected. 
     The air treatment unit can be operated to disinfect with air movement induced through the duct  24  and/or by the air moving assembly  18 . That is, the forced air source  26  and air moving assembly  18  may be separately operated or operated together, in the latter case causing a synergistic effect. 
     Many different variations of the above-described structure are contemplated. Several such variations are described hereinbelow using the same basic components and concepts described above, with it being understood that all like functioning components are interchangeable between the different embodiments. 
     In one form, the basic air treatment unit  10  may be made without its own, or any, air moving assembly, identified at  18  in  FIGS. 1-3 . With the dotted line showing of the air moving assembly  18  in  FIGS. 1-3 , the schematic representations depict the air treatment unit  10  in alternative forms both with and without an air moving assembly  18  being a part thereof. 
     In other words, the invention contemplates that air flow is somehow induced into the volume  20 /primary treatment volume  28  and therefrom in a radial direction relative to a reference axis for the volume  20 /preliminary treatment volume  28  to produce the radially outwardly moving air pattern that ultimately results in disinfected air being distributed into the space  22 . 
     This air flow can be induced by an air moving assembly  18  that is part of the air treatment unit  10 , an air moving assembly spaced from the frame  14  and dedicated to operation of the air treatment unit  10 , or another structure, such as one causing air to be delivered through an outlet  200  on a duct  24 , as shown in  FIGS. 1 and 3 , from the source  26  to condition the space  22 , as by cooling, heating, moisturizing, dehumidifying, etc. 
     Alternatively, conditions in a room may cause natural convection which more passively causes the air to move guidingly into the volume  20 /primary treatment volume  28 , and in a radially outwardly moving pattern, during which movement the air is disinfected by the light rays from the UV light source  16 . 
     In further explaining variations of the above embodiments, description is made with reference to an axis, generally identified at  202  in  FIG. 16 . The axis  202  extends through the volume  20 /primary treatment volume  28  and generally represents the location away from which air flow is directed from within the volume  20 /primary treatment volume  28  in a “radial” direction, as indicated by the arrows  204 . 
     In the specific embodiments illustrated in  FIGS. 4-15 , and described hereinabove, the air travels in a radially outwardly moving pattern substantially fully around the reference axis, which corresponds to what is depicted schematically in  FIG. 16 . It should be understood that within the description of a full 360° pattern around a reference axis, it is contemplated that there might be certain frame structures or other structures that block some of the radial flow. However, even with such discrete blockage, the overall pattern is considered to be substantially a full 360°. 
     The basic concepts and structures described above can also be adapted to deliver disinfected air in a radial outward pattern that is dictated by the geometry of the region at which the air treatment unit  10  is placed. For example, a modified air treatment unit  10   a  might be placed at an inside corner location at  206 . From the reference axis  202   a , the angular dimension θa for the radially outwardly moving pattern of disinfected air, indicated by the arrows  204   a , is on the order of 90°. 
     Another form of air treatment unit  10   b  may be matched to an outside corner region at  208  whereby the angle θb around the axis  202   b , corresponding to the angle θa, is on the order of 270°. The arrows  204   b  show the direction of the radially outwardly moving air pattern. 
     As shown in  FIG. 19 , an air treatment unit  10   c  may be placed against a vertical wall surface  210  whereby the flow pattern angle θc around the axis  202   c , indicated by the arrows  204   c , is on the order of 180°. 
     It should also be emphasized that heretofore, the axis  44 , corresponding to the axis  202 , has been generally designated as vertical, which is a preferred orientation for the air treatment unit, whether suspended from a ceiling or wall mounted. The arrangements shown in  FIGS. 17-19  can be ceiling and/or wall mounted. However, the reference axis may be horizontal and at any angle between horizontal and vertical. In all embodiments, whether the axis identified generically or as “vertical”, the intent herein throughout the Detailed Description and claims is that the axis orientation is not limited by its orientation, with “vertical” being adopted to provide a simple frame of reference throughout the description and claims. 
     Starting with the generic descriptions above, and using components in the exemplary embodiments, numerous different variations of the air treatment unit, with and without an air moving assembly, can be produced, representative ones of which are shown schematically in  FIGS. 20-26 , below. 
     As shown in  FIG. 20 , the air moving assembly  10   a  effectively is a combination of: a) a fan  18   a  on a frame  14   a , which fan  18   a  moves air parallel to the axis  202   a ′ upwardly into the primary treatment volume  28   a ; and b) a forced air source  26   a  delivering air axially downwardly through a duct  24   a  that causes flow mixing, resulting in untreated air being drawn axially upwardly by the fan  18   a  and disinfected air being discharged radially from the primary treatment volume  28   a  as respectively indicated by the arrows DA (disinfected air flow) and UA (untreated air flow). As in the prior embodiments, UV rays may effect further air treatment radially outside the frame  14   a , as potentially occurs with the other embodiments in  FIGS. 21-36 , described below. 
       FIG. 21  discloses an air treatment unit  10   b , with a frame  14   b , similar to the air treatment unit  10   a  in  FIG. 20 , with an air inputting duct  24   b  but without any fan corresponding to the fan  18   a . The direction of disinfected air is, as shown by the arrows DA, similar to that in  FIG. 20 , without the effects of turbulence resulting from the colliding air inputs. Provision may be made to circulate room air back into the primary treatment volume  28   b.    
     In  FIG. 22 , an air treatment unit  10   c  is depicted wherein a fan  18   c  on a frame  14   c  is incorporated as in  FIG. 20  but with a duct  24   c  drawing air so as to cause it to move oppositely to how air moves in the duct  24   a , thereby producing a low pressure region within the primary treatment volume  28   c . The result of this construction is that untreated air flows axially inwardly as indicated by the arrows UA, with disinfected air flowing radially outwardly as indicated by the arrows DA. 
     The air treatment unit  10   d  in  FIG. 23  is similar to that in  FIG. 22 , but does not use a fan, corresponding to the fan  18   c , on its frame  14   d . Air flows in the duct  24   d  in the same direction as the air flows in the duct  24   c  in  FIG. 22 , thereby to produce a low pressure volume with a resulting radial and/or axial inflow to the primary treatment volume  28   d  of untreated air, as indicated by the arrows UA, and outflow of disinfected air, as indicated by the arrows DA. 
     In  FIG. 24 , an air treatment unit  10   e  corresponds to the unit  10   a  in  FIG. 20 , without any axial delivery of air through any duct corresponding to the duct  24   a . A fan  18   e , on a frame  14   e , moves air axially into the primary treatment volume  28   e , thereby causing radial delivery of disinfected air, as indicated by the arrows DA. 
       FIG. 25  depicts an air treatment unit  10   f , corresponding in construction to the air treatment unit  10   e , with the exception that a fan  18   f  on a frame  14   f  moves the air axially from the primary treatment volume  28   f . This produces a low pressure at the lower region of the primary treatment volume  28   f , thereby potentially allowing a certain volume of untreated air to be delivered radially to the primary treatment volume  28   f  from the space, as indicated by the arrows UA, and disinfected air to be expelled radially from the primary treatment volume  28   f  in the direction of the arrows indicated by DA. 
       FIG. 26  discloses an air treatment unit  10   g  with a frame  14   g  and which has no air moving assembly—fan or forced air—and thus relies upon natural convection to cause untreated air to migrate into the primary treatment volume  28   g , with disinfected air discharged in the direction of the arrows DA. 
     The various configurations above are exemplary but do not make up all potential different layouts that might be devised, according to the invention, to cause different air movement to thereby induce flow of air into and from within the primary treatment volume in the radially outwardly moving pattern. 
     Further, in the  FIG. 26  embodiment, the convection may be altered by other dedicated or non-dedicated structure(s). For example, temperature differences may cause air to move in paths that induce a flow of untreated air into the primary treatment volumes and expulsion of disinfected air therefrom. Natural flow of air caused by doors, vents, windows, etc. may facilitate this air flow pattern development. 
     As shown generically in  FIG. 27 , UV lamps  16   a ,  16   b ,  16   c ,  16   d  are preferably strategically placed in spaced relationship to the axis  202  in a surrounding arrangement whereby air is caused to be substantially uniformly exposed to UV rays generated by the lamps  16   a - 16   d  in operation. While four such lamps  16   a - 16   d  are shown, less than four or greater than four might be utilized depending upon the particular shape and size of the frame on the air treatment unit. Further, while straight UV lamp configurations are depicted above, the lamp shapes are not limited. For example, a curved shape might be integrated into the design, as could be a full ring-shaped lamp. 
     The UV lamps  16   a - 16   d  are selected to optimize air treatment. As noted above, there are different zones of treatment resulting from the basic design described above. That is, the air is preferably exposed within the primary treatment volume to a relatively uniform density of ultraviolet rays. Between the aforementioned slats, the louver volume is exposed to ultraviolet rays, which is identified above as the “kill zone”. A more passive exposure of the air to the UV rays occurs as the air is expelled radially from the louver volume between slats. Thus, the overall system is designed to coordinate the exposure in these three zones to optimize the progressive disinfecting of the air, starting within the primary treatment volume and continuing to where the air resides outside of the frame and within the particular space in which treated air is desired. 
       FIG. 28  depicts a generic form of cooperating slats  212   a ,  212   b ,  212   c ,  212   d , corresponding to the slats  46 , described above. As depicted, each of the slats  212   a - 212   d  is of generally flat shape and resides effectively within a plane Pa, Pb, Pc, Pd, successively. Representative slats  212   a ,  212   b  have flat surfaces  214 ,  216 , respectively, which face each other and bound a louver volume  218 , making up a portion of the aforementioned “kill zone”. The other slat pairs  212   b ,  212   c ;  212   c ,  212   d  cooperate in the same fashion. As depicted, the slats  212   a - 212   d  have the same shape and locations, as viewed from an axial perspective. While this is not required, a certain level of radial overlap, identified from the axial perspective, is preferred to create “kill” volumes in which air flow is effectively confined and guided. The planes thereof (Pa-Pd) are substantially orthogonal to the axis  202 . There is no requirement that the slats have the same construction or that the spacing therebetween be identical. In the depicted form, the slats  212   a - 212   d  have the same configuration, spacing, and orientation. 
     While the frame perimeter from the axial perspective in the above-described embodiments is square or rectangular, this shape is not critical. For example, as shown in  FIG. 29 , the frame  14   h  could have a round shape, or any other shape best matched to its particular location, with an axis  202 . 
     As further noted above, the ceiling mount is the most common location with a full 360° coverage. However, the same type of unit could be used on a vertical wall so that the axis  202  is horizontal, or assume another orientation, and still function effectively. 
     As depicted in the prior embodiments, multiple UV lamps are situated at substantially the same axial location. The lamps could be axially stacked or in a staggered relationship. 
     As depicted, the UV lamps are preferably at least partially radially inside of the slats  212  and the louver volumes  218  wherein air guidingly moving therethrough continues to be disinfected. 
     The invention is further directed to a method of treating air in a space, as shown in flow diagram form in  FIG. 30 . 
     As shown at block  220 , an air treatment unit is obtained having a frame configured to define a primary treatment volume with an axis, together with a source of UV light. 
     As shown at block  222 , the frame is placed in an operative position relative to a space in which air is to be treated. 
     As shown at block  224 , air within the space is caused to be moved into the primary treatment volume and disinfected by being exposed to UV rays generated by the source of UV light and the disinfected air is controllably guided through the frame in a radially outwardly moving pattern extending through at least 90° around the axis. 
     The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.