Abstract:
A UV sterilization chamber is provided to a humidifier having a water reservoir, a humidifying element and a pathway for directing water provided by the water reservoir to the humidifying element of the humidifier. The pathway is provided in a humidifier base, over which a humidifier enclosure is removably placed. The UV sterilization chamber includes a serpentine portion of the pathway and a UV radiation source positioned for illuminating the portion of the pathway with UV light. Upwardly-directed projections in the base border a perimeter of the pathway; and a downwardly-directed projection of the UV radiation source extends between the upwardly-directed projections when the enclosure is mated with the base, thereby locating the UV radiation source over the portion of the pathway. A switch disables the UV radiation source when the enclosure is removed from the base.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to humidifying devices, and more specifically, to an ultraviolet (UV) sterilization chamber suited for use in an evaporative humidifier. 
       BACKGROUND OF THE INVENTION 
       [0002]    Humidifying devices, or humidifiers, are used to moisturize the ambient air in a room, most commonly, a single room of a home. Evaporative (or wick) humidifiers, for example, utilize a reservoir of water, from which the wick draws moisture, and a fan forces air through and/or past the wick, thereby picking up moisture in the air as it is directed through a spout or vent into the room. 
         [0003]    It is well known that ultraviolet (UV) irradiation may be used to reduce or eliminate the various minerals, microorganisms, and other contaminants in water. In particular, UV irradiation has been provided in an evaporative humidifier to sterilize the water supply to the wick. See, for example, the evaporative humidifier as described in the commonly-owned U.S. Pat. No. 7,513,486, (“the &#39;486 Patent”), the entire contents of which are incorporated by reference herein. 
         [0004]    In order for sterilization to be achieved, the water being provided to the wick must be exposed to UV irradiation for a sufficiently long period of time. In the &#39;486 Patent, a UV lamp is provided in a disinfection unit and the lamp is surrounded with a helical ramp around which the supplied water travels prior to reaching the wick. By traveling along the extended path provided by the helical ramp as it is irradiated by the UV lamp, the supplied water receives sufficient irradiation for effective sterilization. However, this unit is relatively complex to fabricate, and subjects the quartz tube to the risk of being directly contacted by the water as a result a failure of the unit. 
       SUMMARY OF THE INVENTION 
       [0005]    According to an embodiment of the present invention, a novel UV sterilization chamber is disclosed for use in a humidifier having a fellable water reservoir, a humidifying element and a pathway for directing water provided by the fillable water reservoir to the humidifying element of the humidifier. The pathway is provided in a base of the humidifier, over which an enclosure of the humidifier is removably placed. The sterilization chamber includes a portion of the pathway and a UV radiation source that is provided in the enclosure and positioned over the portion of the path way for illuminating the portion of the pathway with UV light. Upwardly-directed projections are provided in the base that border a perimeter of the pathway; and a downwardly-directed projection of a housing for the UV radiation source is configured to extend between the upwardly-directed projections when the enclosure is mated with the base in order to locate the UV radiation over the portion of the pathway to be illuminated. The downwardly-directed projection of the housing includes a radiation window for emitting the UV radiation. The housing also includes a switch configured to disable the UV radiation source when the enclosure is removed from the base 
         [0006]    The housing further preferably includes a reflector for reflecting UV light emitted from a UV lamp downwardly through the radiation window. In addition, the illuminated portion of the pathway preferably comprises a serpentine pathway, which increases the time of travel of the water through the pathway and thereby the time of exposure to the UV radiation as a sterilant. 
         [0007]    By configuring the humidifier to include a base with a removable enclosure in which the water pathways are primarily confined to the base unit, and in which the UV radiation source is easily and readily separated and removed from these water pathways, fabrication and cleaning of the humidifier are simplified over prior art systems. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings of illustrative embodiments of the invention in which: 
           [0009]      FIG. 1  is a perspective cutaway view of a humidifier including a UV sterilization chamber in accordance with a preferred embodiment of the present invention; 
           [0010]      FIGS. 2A-2D  are exploded perspective views of component sections of the humidifier of  FIG. 1 ; 
           [0011]      FIG. 3  is a top view of a base of the humidifier of  FIG. 1 ; 
           [0012]      FIG. 4  is bottom view of the humidifier of  FIG. 1 , with the base of  FIG. 3  having been removed; 
           [0013]      FIG. 5  is a front exploded view of the humidifier of  FIG. 1 , with cutaway portions showing elements of the UV sterilization chamber in a separated state; and 
           [0014]      FIG. 6  is a front exploded view of the humidifier of  FIG. 1 , with cutaway portions showing elements of the UV sterilization chamber in an engaged state. 
       
    
    
       [0015]    Like reference numerals are used in the drawing figures to connote like components of the humidifier. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]    A preferred embodiment of an ultraviolet (UV) sterilization chamber for a humidifier according to the present invention is described below. This embodiment is provided for the purpose only of illustrating principles of the present invention, and should not be interpreted as limiting the invention in any way beyond the scope of the claims and their equivalents. 
         [0017]    Referring to  FIG. 1 , a humidifier  100  includes a body  1  carried on a base  20 . The base  20  has a molded ring  20   a  (see, e.g.,  FIG. 3 ) for carrying a water reservoir  50 , as well as a molded ring  20   b  for carrying a wicking filter  21 . The filter  21  is preferably formed from several layers of “expanded” cellulose (paper), each layer of cellulose being slit and stretched into a non-raveling open mesh and then mechanically or adhesively adhered to the other layers. This filter design enables water to be fully absorbed while maintaining air flow through the cellulose layers in order to achieve a maximum evaporation rate. Expanded cellulose filters of this type may be obtained, for example, from Columbus Industries, Inc. of Columbus, Ohio. 
         [0018]    Water exiting the water reservoir  50  is directed from a compartment  20   f  defined by molded ring  20   a  along a series of molded paths  20   c,    20   d  and  20   e  to a compartment  20   g  defined by the molded ring  20   b  and a molded insert  20   i  (see, e.g.,  FIG. 3 ). The filter  21  rests within the compartment  21 , and absorbs water by capillary action (“wicking”) to moisten a substantial volume of the filter. The moisture is evaporated from the filter with the assistance of a fan and control unit  60 , which draws air through vents  20   h  of the base  20  and around the filter  21  to be exhausted through a grill  4  positioned in an opening  1  a in the upper surface of the body  1 . 
         [0019]    With reference to  FIGS. 2B and 2C , a UV lamp  41  is positioned within a quartz glass tube  27  in a lower cavity of a motor cavity  2  of the fan and control unit  60 . The UV lamp  41  may preferably be a filament-type, 4-watt UV lamp that produces UV radiation having wavelengths in the UV-C (or shortwave) range of 200 to 280 nanometers, which may be obtained for example from Osram Sylvania of Danvers, Mass. Radiation in the UV-C range has been proven effective as a mutagen in the destruction of the DNA of micro-organisms such as pathogens, viruses, bacteria and molds, thereby preventing their reproduction. See, e.g., Philip W. Brickner, MD et al., “The Application of Ultraviolet Germicidal Irradiation to Control Transmission of Airborne Disease: Bioterroism Countermeasure,” Public Health Reports, Vol. 118, March- April 2003, pp. 99-119, which is incorporated by reference herein. 
         [0020]    A UV bracket  9  is fastened at a bottom surface of the cavity to retain the UV lamp  41  and quartz glass tube  27  within the cavity, and includes an aperture  9   b  (see, e.g.,  FIG. 4 ) permitting UV light from the UV lamp  41  to be downwardly directed toward the molded path  20   d  to irradiate water in the molded path  20   d,  through which water provided by the water reservoir  50  is directed to the filter  21 . 
         [0021]    With reference to  FIG. 2A , an exploded diagram further illustrates the body  1 , the grill  4  and a knob  5 . The body  1  may be formed in any number of shapes, and as shown is preferably formed as a substantially rectangular box made of molded plastic. The knob  5  attaches to a switch  40  of the fan and control unit  60  (see  FIG. 2B ) at an aperture  1   d  in a ring  1   e  located at the upper surface of the body  1 . In addition, an aperture  1   g  is provided in the ring  1   e  adjacent to the aperture  1   d.  The ring  1   e  is integrally formed with a vertical rib  1   f  of the body  1 . 
         [0022]    The body  1  further includes a cavity  1   b  for receiving the water reservoir  50 , and a slot  1   c  through which an indicator portion  22   c  of the tank member  22  of the reservoir  50  protrudes in order to provide a visual indication of the water level in the reservoir  50 . 
         [0023]    With reference to  FIG. 2B , the fan and control unit  60  includes a fan blade  3  which is installed on a drive shaft  33   a  of motor  33  and retained by a circlip  33   b  or other suitable fastener. The fan blade  3  may preferably be a five-bladed, seven-inch axial blade design, or any other suitable design. 
         [0024]    The fan motor  33   a  is mounted in a motor bracket  2   f  that is mounted to base member  2   g  within a bowl  2   b  of the motor bracket  2  (see, e.g.,  FIG. 4 ), and is controlled by conventional control circuitry that is mounted on a printed circuit board (PCB)  30  via a rotary switch  40 . The fan motor  33   a  may preferably be a 1380 RPM, single-phase shaded-pole 120 VAC motor (conventionally referred to as a “universal” motor), or a motor of other suitable design. Alternatively, the fan motor  33   a  may be a 1380 RPM, single-phase shaded-pole motor operating at 220-240 VAC. Motors of these types may be obtained, for example, from Wolong Electric Group, Ltd. Of Shangyu (Zhejiang province), China. 
         [0025]    The rotary switch  40  is preferably a multiple position switch that, in combination with the control circuitry, enables a user to operate the fan at several selectable fan speeds. 
         [0026]    The base member  2   g  may preferably include a rim  2   h  which is configured to locate the upper surface of the cylindrical filter  21  against the base member  2   h.  Similarly, molded ring  2   b  locates a bottom surface of the cylindrical filter  21  against a bottom surface of the compartment  20   g.  In this configuration, the fan operates to draw air through vents  20   h  in the base  20  toward an external surface of the cylindrical filter  21  through to an interior of the filter  21  to be exhausted through the grill  4  positioned in the opening  1   a  in the upper surface of the body  1 . 
         [0027]    With reference to  FIG. 2B , the PCB  30  is housed in a PCB box  7  having a PCB box cover  8 , which is housed within a control compartment  2   c  of the motor bracket  2 . The PCB  30  also controls the operation of the UV lamp  41 , as will be further described herein, and a light emitting diode (LED)  32 , which is housed in a lamp shade  6 . The rotary switch  40  and the LED  32  in its lamp shade  6  are mounted to a rotary switch cover  17 , which is fastened to one or more of the body  1  and motor bracket  2  so that the rotary switch  40  protrudes through the aperture  1   d  and the lamp shade  6  extends through the aperture  1   g . The lamp shade  6  is firmly fitted within the aperture  1   g  by means of an O-ring  16 . The LED  32 , in combination with the control circuitry, is preferably configured to indicate one or more of “power on” condition and/or a “maintenance needed” condition (for example, filter or UV lamp replacement) for the humidifier  100 . The LED  32  may preferably be configured to emit several colors of light under the control of the PCB  30  in order to indicate different operating conditions of the humidifier  100 . 
         [0028]    A conduit  2   e  of the motor bracket  2  reaches to the base  20  and provides a path for a conventional power cord  38  (see, e.g.,  FIG. 2C ) to extend externally from the humidifier  100 . 
         [0029]    With reference to  FIG. 2C , the base  20  is shown with reference to the filter  21  and a UV lamp unit including the UV lamp  41  and the quartz glass tube  27 . As shown, the base  20  is preferably provided with rubber feet  31  at each corner of the base  20  for stable placement of the base  20  on an operating surface. 
         [0030]    The lamp  41  and the quartz glass tube  27  are housed in a UV box  18 . A UV lamp holder electrically interconnected to the PCB  30  (see  FIG. 2B ), is inserted through an aperture of a UV box cover and receives the UV lamp  41 . In order to guard against the ingress of moisture to the vicinity of UV lamp  41 , seal pads  29  are provided at either end of the quartz glass tube  27  to seal the quartz glass tube  27  against end faces of the UV box  18  and UV cover  19 . The assembled UV box  18  and UV box cover  19  are enclosed by a cap  14  and the UV bracket  9 , and the entire assembly is inserted into a UV lamp unit compartment  2   a.  The UV bracket  9  is sealed to the UV lamp unit compartment  2   a  by means of an O-ring  15 . As illustrated, the UV box  18  includes an upper member  18   a  that is arced (preferably along a parabolic profile). An inner surface of the upper member  18   a  is preferably provided with a reflective material, such that the inner surface of the upper member  18   a  is effective to direct UV light radiated by the UV lamp  41  downwardly to irradiate water in the molded path  20   d  of  FIG. 3 . When a filament-type, 4-watt UV-C lamp is provided in the UV box  18 , the upper member  18   a  is provided with the reflective material and the UV lamp  41  is positioned less than one inch above a surface of the water in the molded path  20   d,  it is possible to achieve a germ-killing effectiveness of 99.99%. 
         [0031]    The cap  14  and UV bracket  9  further mount a microswitch  39 , fixed chip  12  and push rod  13  to the UV lamp unit. The microswitch  39  is also electrically interconnected to the PCB  30 . The push rod  13  is preferably fabricated from silicone rubber, and a rod portion  13   a  extends through an aperture in the fixed chip  12 . The rod portion  13   a  of the push rod  13  is positioned for actuating the microswitch  39 , and a base portion  13   b  of the push rod  13  is placed in contact with the UV bracket  9  over an aperture  9   a  (see, e.g.,  FIG. 4 ) positioned to be flexibly displaced by a pin  20   j  of the base  20  (see, e.g.,  FIG. 3 ). When the body  1  of the humidifier  100  is placed onto the base  20 , the pin  20   j  extends through the aperture  9   a  to flexibly displace the base portion  13   b  of the push rod  13 , such that the rod portion  13   a  engages the microswitch  39  to switch the microswitch  39  to an electrically closed position. In this position, the UV lamp is powered when the rotary switch  41  is switched to an operating position. When the body  1  is removed from the base  20 , the pin  20   j  exits the aperture  9   a  and the rod portion  13   a  of the push rod  13  retracts to switch the microswitch  39  to an electrically open position. In this position, one or more of the UV lamp and or the fan unit are inoperative regardless of the position of the rotary switch  41 . 
         [0032]    With reference to  FIG. 2D , the water reservoir  50  includes a tank member  22  which may be formed in any of a variety of volumetric shapes that may be suitable for coupling the water tank  100  to the humidifier. A principal portion of the tank member  22  has an approximately trapezoidal lower face  22   a  with rounded vertices, and extends upwardly along a longitudinal direction of the portion with a continuously expanding cross-section that reaches its maximum cross-sectional area at an upper face  22   b.  Respective perimeter edges  22   f,    22   g  of the lower face  22   a  and upper face  22   b  are also rounded, and join side walls  22   h,  a rear wall  22   j  and a front wall (not shown) of the principal portion to the lower face  22   a  and upper face  22   b,  respectively. 
         [0033]    The tank member  22  further includes a handle portion  22   d  that extends upwardly from a rear portion of the upper face  22   b  and forward from this portion, but not completely across the upper face  22   b.  Over the portion of the upper face  22   b  that the handle portion  22   d  extends, it has essentially the same cross-section as this portion of the upper face  22   b.    
         [0034]    A front region  22   i  of the handle portion  22   d  is slightly inset to receive a tank cover  25 . The tank cover  25  preferably includes a gripping portion  25   a  for gripping by a human hand, and recesses  25   e  which mate with projections  22   e  on the tank member  22  in order to positively locate the tank cover  25  over the front region  22   i  of the handle portion  22   d.  The tank cover  25  in addition may be optionally bonded to the handle portion  22   d  with a conventional adhesive. 
         [0035]    An indicator portion  22   c  of the tank member  22  extends rearwardly from the rear face  22   k  of the tank member  22  and handle portion  22   d  As illustrated in  FIG. 1 , a depth of the indicator portion  22   c  increases in a downward vertical direction, while a width of the indicator portion  22   c  decreases in the downward vertical direction. The indicator portion  22   c  of the water tank  100  is configured for example to extend through a wall of the humidifier to provide a visual indication to the user regarding the fluid level in the tank member  22 , 
         [0036]    At the lower face  22   a,  a round, externally threaded opening  22   j  is provided for receiving a cap  23 , which has an inner thread for mating with an outer thread of the threaded opening  22   j.  The cap  23  is provided with an O-ring  23  for sealably securing the cap  23  to the threaded opening  22   j  of the tank member  22 . 
         [0037]    A valve bar  34  is positioned within a central aperture  23   a  of the cap  23 . A downward force is exerted on the valve bar  34  by a spring  36 , which is fitted over the valve bar  34  and between a flange  34   b  of the valve bar  34  and the upper surface of a spring cup (not shown) of the cap  23 . A rubber valve member  35  is lockably fitted to a groove  34   a  of the valve bar  34 , and serves to restrict further downward movement of the valve bar  24  when the valve member  35  is interferingly pulled by the force of the spring  36  against the central aperture  23   a.  When inserted into the compartment  20   g  of the base  20 , a post  20   j  (see, e.g.,  FIG. 3 ) positioned at the center of the compartment  20   g  is pressed against a bottom surface of the flange  34   b  of the valve bar  34 , thereby raising the valve member  35  above the central aperture  23   a  and permitting fluid in the water tank  100  to flow around the valve  34   a  and through the central aperture  23   a  for delivery to the wick of the humidifier. 
         [0038]    With reference to  FIG. 3 , the base  20  as previously described includes the compartment  20   f  defined by the molded ring  20   a,  the compartment  20   g  defined by the molded ring  20   b  and the molded insert  20   i,  and the molded paths  20   c,    20   d  and  20   e  which interconnect and enable water to flow from the compartment  20   f  to the compartment  20   g . Molded path  20   d  is positioned near the center of the base  20 , and has a serpentine shape defined by vanes  20   k  and  20   l . The serpentine path carries water supplied by the path  20   c  near a front side of the base  20  to the path  20   d  near the rear side of the base  20 . Each of paths  20   c  and  20   e  carry water across the base  20  to the serpentine path  20   d.    
         [0039]    In  FIG. 3 , the serpentine path  2   d  is shown with a region  20   n,  With reference to FIG,  4 , the region  20   n  corresponds to a position occupied by a first rectangular projection  9   c  of the bracket  9  when the body  1  of the humidifier  100  is placed onto the base  20 . As the first rectangular projection  9   c  includes the aperture  9   b  through which UV light from the UV lamp  41  is emitted, water carried within the serpentine path  2   d  is thereby irradiated. By following the serpentine path defined by the molded path  2   d,  the amount of time required for water to be carried along the path is increased, thereby increasing the time that the water is exposed to the UV light and increasing the effectiveness of the UV sterilization. 
         [0040]    With reference to  FIG. 4 , the bracket  9  includes the first rectangular projection  9   c  and a second rectangular projection  9   d  that extend downwardly from a base bottom surface  9   e  of the bracket  9 . When the body  1  of the humidifier  100  is placed on the body  20 , the first rectangular projection is positioned over the region  20   n  of FIG,  3 , and the second rectangular projection is positioned over a region  20   m  of  FIG. 3 . As further shown in  FIG. 3 , the perimeter of regions  20   m,    20   n  is bordered by molded projections  20   o  and  20   q.  The region  20   m  further includes a pad  20   p,  which also defines a portion of the serpentine path  20   d.    
         [0041]    Upper surfaces of each of the vanes  20   k,    20   l  and the pad  20   p  lie below the upper surfaces of the molded projections  20   o,    20   q.  As a result, when the body  1  of the humidifier  100  is placed on the body  20 , the first and second projections  9   c,    9   d  extend below the upper surfaces of the molded projections  20   o,    20   q  into the regions  20   n,    20   m,  respectively. In this manner, the molded projections  20   o,    20   q  operate to properly locate the first and second projections  9   c,    9   d  (and the UV lamp  41  positioned above the aperture  9   b ) with respect to the serpentine path  20   d,  and thereby assist in confining the emitted UV light to the serpentine path. 
         [0042]    These features can be further illustrated as follows.  FIGS. 5 and 6  each show the body  1  and the base  20  of the humidifier  100  in partially broken views that make visible elements of the disclosed UV sterilization chamber.  FIG. 5  illustrates the humidifier  100  in a state in which the body  1  has been separated from the base, and  FIG. 6  illustrates the humidifier  100  in a state in which the body  1  has been placed onto the base  20 . With reference to  FIG. 6 , it can be seen that, when the body  1  is placed onto the base  20 , the first projection  9   c  is directed between the molded projections  20   o,    20   q  until portions of the base bottom surface  9   e  rest on the upper surfaces of the molded projections  20   o,    20   q.  In this position, a bottom surface of the first projection  9   c  extends below the top surfaces of the molded projections  20   o,    20   q  and the top surface of the pad  20   p,  in proximity to the top surfaces of the vanes  20   k  and  20   l . Side surfaces of the first projection  9   c  substantially abut side surfaces of the molded projections  20   o,    20   q , thereby locating the first projection  9   c  over the serpentine path  2   d  in a substantially fixed position. 
         [0043]    While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. For example, the first and second rectangular projections of the UV bracket may be made in any of a variety of shapes determined as a function of the humidifier design (in particular, as a function of the corresponding molded projections of the base. In addition, the serpentine path may include any of a variety of configurations of folded paths, and the serpentine path and lamp unit may be positioned at any of a variety of positions relative to a footprint of the base. 
         [0044]    Accordingly, the invention is to be limited only by the scope of the claims and their equivalents.