Abstract:
An angled germicidal lamp is used to illuminate a coil and drain pan for optimum energy utilization. An angled mount formed of two retention clips positions a germicidal lamp at a desired angle. A security access cover ensures that the germicidal lamp is disconnected from its power supply before access. Multiple germicidal lamps may be mounted by a single retention clip.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional under 35 USC § 120 of U.S. application Ser. No. 10/403,260, filed Mar. 31, 2003 to Burnett, which is a continuation-in-part of U.S. Pat. No. 6,539,727 (U.S. Ser. No. 10/026,167) to Burnett, filed Dec. 21, 2001, issued Apr. 1, 2003, entitled “Angled UV Fixture”. 
     
    
     STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable  
       BACKGROUND OF THE INVENTION  
       [0003]     1. Technical Field  
         [0004]     This invention relates in general to air conditioning systems and, more particularly, to ultraviolet light fixtures.  
         [0005]     2. Description of the Related Art  
         [0006]     Over the last several years, the use of ultraviolet (UV) light in commercial and residential air conditioning applications has become more popular. A UV light source in the UV-C spectrum, specifically at 253.7 nm, and potentially UV light in other frequencies such as 187 nm, has been shown to be extremely effective in destroying bacteria and fungi in air conditioning systems.  
         [0007]     During operation of an air-conditioning system, water condenses on the heat exchanger (typically referred to as the condensing coil). The drain pan is situated below the coil and collects run-off from the coil. Because the cool and moist environmental conditions in the coil are conducive to microbial infestations, UV lamps are often used to illuminate the coil and drain pan. U.S. Pat. No. 5,817,276 to Fencl et al claims that the UV lamp should be oriented perpendicular to the fins of the coil for maximum reflection within the coil.  
         [0008]     Mounting a substantially straight lamp perpendicular to the fins, however, has some significant shortcomings. First, in some orientations, the fins will be horizontal in relation to the drain pan. If a substantially linear UV lamp is mounted perpendicular to the drain pan, its effectiveness in killing bacteria in the drain pan may be reduced. Further, mounting a linear UV lamp perpendicular to the fins may result in the use of a relatively short UV lamp, which will not emit as much UV energy as would a longer lamp.  
         [0009]     In U.S. Ser. No. 10/026,167, filed Dec. 21, 2001, entitled “Angled UV Fixture” to Burnett, which is incorporated by reference herein, an angled UV lamp fixture is shown. The angled orientation overcomes many of the shortcomings of the prior art.  
         [0010]     It is also important that a UV lamp be mounted inexpensively and securely, with precautions taken to reduce the risk of inadvertent UV exposure.  
         [0011]     Therefore, a need has arisen for a method and apparatus for UV filtration that maximizes energy to the coil and drain pan for higher microbial efficacy.  
       BRIEF SUMMARY OF THE INVENTION  
       [0012]     In a first aspect of the invention, a mounting system for mounting a germicidal lamp to a sidewall at an angle comprises first and second slide clips. The first slide clip has a planar surface having an opening for engaging the germicidal lamp and an extended portion formed at an angle to said first planar surface, such that the planar surface is held at an desired angle relative to the sidewall when the first slide clip is positioned against the sidewall with the extended portion in contact with the sidewall. The second slide clip has a planar surface with an opening for engaging the germicidal lamp and is slideably engaged with said first slide clip.  
         [0013]     In a second aspect of the invention, a germicidal lamp is mounted in a duct. An access cover is coupled to the duct for covering said germicidal lamp, where the access cover has a hole formed therein for receiving an electrical connection to the contacts.  
         [0014]     In a third aspect of the invention, an integral piece of material has openings formed therein for receiving a plurality of germicidal lamps. The integral piece of material is secured to a sidewall to mount the germicidal lamps.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0015]     For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:  
         [0016]      FIG. 1   a  illustrates a perspective view of a coil illuminated by a angled germicidal lamp;  
         [0017]      FIGS. 1   b  and  1   c  illustrates top and side cross-sectional views of  FIG. 1   a;    
         [0018]      FIG. 2  illustrates a first embodiment of an angled mounting system;  
         [0019]      FIG. 3  illustrates an exploded view of a retainer mechanism;  
         [0020]      FIGS. 4   a  and  4   b  illustrate side and front views of the retainer mechanism of  FIG. 3   a  in a locked position;  
         [0021]      FIGS. 5   a  and  5   b  illustrate top and side views of an alternative embodiment of an angled mounting system;  
         [0022]      FIGS. 6   a  and  6   b  illustrate top and side views of a security access cover for preventing access to a UV lamp without prior disconnection of the ballast power supply;  
         [0023]      FIG. 6   c  illustrates a top view of a flanged plug for use with the security access cover of  FIGS. 6   a  and  6   b;  and  
         [0024]      FIGS. 7   a  and  7   b  illustrate side and front view of a multiple lamp mounting clip.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]     The present invention is best understood in relation to  FIGS. 1-7  of the drawings, like numerals being used for like elements of the various drawings.  
         [0026]      FIG. 1   a  illustrates a generalized perspective view of the present invention. A coil  10 , having fins  12  and coolant exchange tubes  14 , is disposed in a duct  15  of an air conditioning system. A drain pan  16  is disposed below the coil, such that condensation from the coil  10  flows into the drain pan  16 . A germicidal lamp  18  is disposed between a first position near an upper corner  20  of the coil  10  and a second position near opposite lower corner  22 . Airflow is shown as passing through a filter  24 , which typically precedes the coil  10  in the direction of the airflow. Generally, the airflow is produced by a blower motor (not shown). The blower motor is often placed between the coil  10  and filter  22 , although it could also be placed before the filter or after the coil. The relative order of the blower motor, filter  24  and coil  22  is not critical for the operation of the present invention. Also, while the duct of  FIG. 1   a  is shown in a horizontal configuration, it could be vertical or at any angle in other configurations. Further, the any type of germicidal lamp  18  could be disposed on either side of the coil, or on both sides. The lamp  18  could be, for example, a single-ended, dual-ended, bi-pin, or mini bi-pin or other configuration. In a dual-ended configuration, an electrical connection to the far side could be made, for example, using a uni-strut angle bracket with the terminal box and electrical connections.  
         [0027]     In operation, the air in duct  15  is forced through the coil  10  by a blower motor. The fins  12  are cooled by the coolant exchange tubes  14 ; hence air passing over the fins is cooled as well. Cooling the air causes condensation to form on the tubes  14  and fins  12 . Gravity causes the condensation to flow towards the drain pan  16 . The cool moist conditions are ideal for the growth and reproduction of bacteria, mold and other microorganisms on the coil  10  and in the drain pan  16 .  
         [0028]     The germicidal lamp  18  shines on both the coil  10  and the drain pan  16 . Typically, the germicidal lamp is a UV-C frequency lamp, which has been shown to be extremely effective in combating bacteria and mold and other airborne organisms. Other frequencies could also be used.  
         [0029]     Placing the germicidal lamp  18  at an angle of  10  degrees to  80  degrees to a duct sidewall  17 , preferably from a position near one corner of the coil  10  towards an opposite corner of the coil  10  (rather than orienting the lamp horizontally or vertically with respect to a sidewall  17  of duct  15 ) provides significant benefits. First, the angled disposition of the lamp  18  allows a longer lamp to be used. A longer lamp provides a greater energy output than a shorter lamp of the same intensity. Hence, more energy is available for destroying microorganisms. The increased energy is particularly evident in the drain pan  16 .  
         [0030]      FIGS. 1   b  and  1   c  illustrate top and side views, respectively, of the air conditioning system of  FIG. 1   a.  In  FIG. 1   b,  an angled mount  26  is shown which allows the germicidal tube  18  to be mounted on a sidewall  17  of duct  15  at a desired angle. Embodiments for the angled mount  26  are shown in greater detail in connection with  FIGS. 2-5 .  
         [0031]      FIG. 2  illustrates a partially cross-sectional view of a first embodiment of an angled germicidal lamp that allows for variable angle positioning.  FIG. 2  illustrates a side view of a germicidal lamp  18  disposed through a hole  19  in duct  15  (shown in cross-section) at an angle set by angled mount  26 . Germicidal lamp  18  is preferably a single-terminated lamp or double-terminated lamp with return wires such that all electrical connections are available at one end of the lamp. Lamp  18  includes an endcap  28  at the end of the lamp  18  within the duct  15  and an endcap  30  at the end of the lamp  18  outside of the duct  15 . Endcap  30  includes a flange  32  which is oriented in a plane perpendicular to the longitudinal axis of the lamp  18 , or at another fixed angle. Electrical contacts  31  protrude endcap  30 ; these contacts are connected to the ballast.  
         [0032]     Angled mount  26  includes angled coupler  34  (shown in cross-section) and restraining mechanism  36 . Angled coupler  34  abuts a sidewall  17  of duct  15  and flange  32 , thus holding the longitudinal axis of lamp  18  at a desired angle to the plane of the sidewall  17  of duct  15  and, consequently, to the coil  10 , as shown in  FIG. 1 . Restraining mechanism  36  holds the flange  32  and angled coupler  34  fixedly against duct  15 .  
         [0033]     In typical installations, the coil  10  is accessible from the outside through a “cabinet” or “housing”. For purposes of this specification, the cabinet or housing will be considered part of the duct  15 . Further, electronics for powering the germicidal lamp  18 , commonly referred to as a “ballast”, are contained in a housing which is typically secured to the outside of the duct  15 . It is possible, and sometimes most efficient, to attach the lamp  18  to the ballast housing; therefore, for purposes of the specification, the ballast housing or any other housing for containing the end of lamp  18 , is considered to be part of the pertinent sidewall  17  of duct  15  as well.  
         [0034]      FIG. 3  illustrates an exploded view of a restraining mechanism  36  that could be used in connection with lamp  18  and angled coupler  34  to hold the lamp  18  at the desired angle. Restraining mechanism  36  includes a slide clip  38  with dual slots  40 . Threaded studs  42 , which are attached to duct  15 , are disposed through respective slots  40 , such that slide clip  38  can travel up and down in relation to the studs  42  when the restraining mechanism is in an “unlocked” state. Nuts  44  are threaded to screw onto studs  42 . On each stud  42 , a locking washer  46  and a spring  48  are disposed about stud  42  on the opposite side of slide clip  38  from nuts  44 .  
         [0035]      FIGS. 4   a  and  4   b  illustrate side and front views of the restraining mechanism  36  of  FIG. 3  in a “locked” position with the nuts  44  tightened to firmly press flange  32  and angled coupler  34  against duct  15  (shown in cross-section in  FIG. 4   a ). The slide clip  38  is placed such that the narrow portion of the opening is set against the endcap  30  with the clip  38  pressing against flange  32 . In this position, springs  48  press lock nuts  46  against the opposite side of slide clip  38  so that the slide clip is restrained by friction from sliding upwards to an unlocked position.  
         [0036]      FIG. 4   b  illustrates a front view of the restraining mechanism in the locked position.  
         [0037]     In operation, the angled germicidal lamp shown in  FIGS. 1-4  can be used to accommodate a variety of coil configurations and sizes. To mount the germicidal lamp, the installer forms hole  19  in the duct  15  through which the lamp  18  will be installed. Typically, the hole would be located on the duct at a position near an upper corner of the coil  20 . The studs  48  are secured to the duct  15  at the sides of the hole  19  (in general, it is beneficial to secure the studs to a plate or chassis to reinforce thinner duct material). A spring  48  and locking washer  46  are placed around each stud  48 . Slide clip  38  is placed over the studs  48  and the nuts  44  are placed over the studs  48 . An angled coupler  34  is chosen such that the lamp  18  is directed to the opposite corner of the coil  20 , as shown in  FIG. 1 . The selected angled coupler  34  is placed around the lamp  18  and positioned against flange  32  at the opposite end of the lamp  18 . The lamp  18  is placed through the hole  19  such that the angled coupler  34  is flush against duct  15  and flange  32  is flush against the angled coupler  34 . The slide clip is placed in a locked position against the flange and the nuts  44  are tightened.  
         [0038]     In general; the lamp is oriented between two opposite corners, as shown in  FIG. 1 . The germicidal lamp  18 , however, should be angled such that the end of the lamp does not protrude lower than the plane of the top of the drain pan  16 . Also, in order to enter at a flat portion of the duct  15 , the lamp may be positioned somewhat below the upper corner of the coil  10 . Typically, the angle of the longitudinal axis of the lamp will be between 10 and 80 degrees relative to the horizontal plane at the top of the coil  10  or at the edge of the drain pan  16 , depending upon the application and the relationship between coil depth, width, height and angle of tilt in the air-handling unit. The lamp  18  could enter the duct at a corner as well, although the mounting may be more difficult.  
         [0039]      FIGS. 5   a  and  5   b  illustrate an alternative embodiment for angling lamp  18 . In this embodiment, an automatically angled restraint mechanism  50  including two slide clips  38  is used to angle the lamp  18 . A “bottom” slide clip  38   a  (i.e., the slide clip  38  closest to the sidewall  17 ) is oriented such that an angled portion  52  and opposite tip  54  cause the planar portion  56  of the clip  38  to form a desired angle with the sidewall  17 . The planar portion  56  of “upper” slide clip  38   b  rests against the planar portion  56  of slide clip  38   a.  The slide clips  38   a  and  38   b  are oriented such that a hole is formed in their interiors to expose hole  19  in sidewall  17 .  
         [0040]     Threaded studs  42 , which are attached to sidewall  17 , are disposed through overlapping slots  40  of both clips  38   a  and  38   b,  such that the slide clips  38  can travel up and down in relation to the studs  42  when the restraining mechanism is in an “unlocked” state. Nuts  44  are threaded to screw onto studs  42 . A locking washer  46  and a spring  48  are disposed about stud  42  between the bottom clip  38   a  and the sidewall  17 .  
         [0041]     The restraining mechanism  50  provides significant benefits to the installer. First, it is easily and inexpensively manufactured from sheet metal. Second, it is easily installed at the site. Third, the angled portion  52  can be designed to support different angles, or it can be bent using standard tools at the installation site to provide the proper angle.  
         [0042]      FIGS. 6   a  and  6   b  illustrate a front view and a cross-sectional side view, respectively, of a security access cover  60  for protecting technicians and home owners from possible electrical shock while servicing the UV lamp  18 . The security box  60  can be used with any UV lamp orientation, either straight or angled. For ease of illustration, the security access cover  60  is shown in  FIG. 6   b  with a straight lamp installation.  
         [0043]     The security access cover  60  is attached to sidewall  17  of duct  15  using, for example, studs  62  and nuts  64 . The security access cover  60  completely covers the endcap  30  of the lamp  18 . An access hole  66  is disposed through the cover to allow access by a plug  68 , including female power socket  70 , power cable  72 , and shield  74  (shown in cutaway view in  FIG. 6   b  to expose the power socket  70 ). The power cable  72  is coupled to the UV ballast (not shown) and supplies power to the pins  31  of lamp  18 .  
         [0044]     In operation, the security access cover is difficult to remove without first disconnecting the plug  68  from the UV lamp  18 . This greatly reduces the possibility of a technician or home owner from UV exposure and from accidental contact with the electrical output of the ballast and prevents anyone from removing the lamp without first disconnecting the lamp from the electricity from the ballast.  
         [0045]      FIG. 6   c  illustrates an embodiment of shield  74  where it is impossible to remove the security access cover  60  without first disconnecting the power. In this embodiment, a flange  76  (or other protrusion) is disposed about the top of shield  74 , such that the flange  76  is located on the top of security access cover  60  when connected to the UV lamp in normal operation. Any attempt to remove the security access cover  60  will cause the flange to automatically disconnect the socket  70  from the lamp  18 . The flange  76  may have text for instructing the individual to remove the plug prior to removing the cover  60 .  
         [0046]      FIGS. 7   a  and  7   b  illustrate front and side views of a multi-lamp slide clip  80 . Multi-lamp slide clip  80  includes a plurality of openings  82 , for securing respective lamps  18  to a sidewall of a duct  15  or other casing, formed in an integral sheet of material, such as sheet metal. In the preferred embodiment, two slots  40  are positioned adjacent to each opening  82 . An angled extension  84  protrudes from the top of the slide clip  80 .  
         [0047]     In operation, the multi-lamp slide clip  80  is used to secure multiple lamps  18  to a duct  15  or to other casing. Studs  48  and nuts  44  may be used to hold the multi-lamp slide clip  80  to the sidewall, as shown above in connection with  FIG. 3 . The lamps  18  can be mounted straight (perpendicular to the sidewall) or at an angle. An angled mount can be achieved by using techniques described above, such as couplers  34  shown in  FIG. 2  or by using two multi-lamp slide clips  80  in the configuration described in connection with  FIGS. 5   a  and  5   b.    
         [0048]     The multi-lamp slide clip allows multiple lamps  18  to be easily installed and removed. The lamps  18  could be used for sterilization of a surface of a coil, a filter, or for general air sterilization.  
         [0049]     An access cover such as that shown in  FIGS. 6   a  and  6   b  could have multiple access holes  66  to cover the lamps secured with the multi-lamp slide clip.  
         [0050]     The retaining assemblies described herein could be used not only to illuminate a rectangular coil, as shown in  FIG. 1   a,  but also with other coil designs, such as an A-coil, described in connection with U.S. Pat. No. 6,539,727 (U.S. Ser. No. 10/026,167) to Burnett, issued Apr. 1, 2003, entitled “Angled UV Fixture”, which is incorporated by reference herein. Additionally, the retaining assemblies could be used in other parts of the air conditioning system to purify filters and other surfaces, and to purify the air itself.  
         [0051]     Although the Detailed Description of the invention has been directed to certain exemplary embodiments, various modifications of these embodiments, as well as alternative embodiments, will be suggested to those skilled in the art. The invention encompasses any modifications or alternative embodiments that fall within the scope of the Claims.