Abstract:
The object of this invention is an automatic air-filter changing system for use in light commercial and residential high-volume air conditioner (HVAC) systems. This invention uses a filter housing that connects to the air return portion of HVAC systems, either in-line (by splicing the air return duct) or as part of the heating/cooling coil structure. The filter housing contains a drive-motor and drive-motor control unit. Within the filter housing, a filter cartridge is placed. The filter cartridge comprises a supply container, a collection container, and filter material. The filter material is initially stored in the supply container of the filter cartridge. The drive-motor of the filter housing advances the filter material from the supply container of the filter cartridge to the collection container of the filter cartridge. The drive-motor control unit controls the frequency and length of filter material advancement. The drive-motor control unit is a programmable unit that supports human interface through a keypad and other devices (such as an LED display) as necessary to enable a person to program the unit. The drive-motor control unit is connected to the drive-motor and controls the frequency and length of filter material advancement by regulating the electrical current supplied to the drive-motor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     No claims to benefits of prior applications are made under this Specification.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     This invention is not the result of federally sponsored research.  
       REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX  
       [0003]     None  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of Invention  
         [0005]     This invention relates to air filters used in light commercial and residential high-volume air conditioner (HVAC) systems. The present invention contains a motorized filter housing in which a filter cartridge is placed. The motorized housing automatically advances the filter material contained in the filter cartridge, resulting in an automatic air filter changing system.  
         [0006]     The applicable U.S. patent Classification Definition for this invention includes, but is not limited to, class “55—Gas Separation,” subclasses “282—With non-liquid cleaning means for separating,” “283—With automatic control of cleaning means,” “351—With means for advancing clean portions of continuous or indefinite length separating media into gas stream,” and “527—Fibrous or strand form.” 55/282, 55/283, 55/351, and 55/527  
         [0007]     2. Description of Related Art  
         [0008]     Conventional HVAC system designs deploy air filters either at the air return registers, in-line within the air return duct or ducts, or at the heating/cooling coils. Air filters are a critical component to modern HVAC systems. Dirty, clogged filters restrict airflow to the system resulting in excess strain on the system, reduced efficiency, and could possibly shorten the mechanical life of the system. As such, HVAC equipment manufacturers recommend changing filters as frequently as every three to four weeks.  
         [0009]     Conventional residential and light commercial-use HVAC systems employ a non-mechanized air filter manufactured in standard shapes and sizes. Introducing a clean air filter into the HVAC system requires removing the existing, non-mechanized filter, discarding the used filter, and installing a replacement filter. This process must be repeated periodically, preferably every four weeks according many HVAC manufacturers.  
         [0010]     While replacing filters is not complicated, many consumers fail to do so and this failure results in increased energy consumption, poor heating/cooling quality, and increased maintenance and repair costs. Previous attempts to automate the replacement of HVAC air filters (such as U.S. Pat. No. 5,217,513) required manual intervention each time the filter required replacement.  
       SUMMARY OF THE INVENTION  
       [0011]     Accordingly, the object of this invention is a more automated HVAC air filter system—a self-changing air filter system.  
         [0012]     The system is composed of a filter housing containing a drive-motor and motor controls and a filter cartridge containing a supply container and collection container. The filter housing may be installed in-line by splicing into the air return duct (the duct providing air to the heating/cooling coils). Additionally, the filter housing may be attached directly to the heating/cooling coil structure itself.  
         [0013]     The filter housing contains a drive-motor attached to a shaft and gear. The drive-motor advances the filter material contained in the filter cartridge by a predetermined amount. The amount of material to advance is based on the size of the air return. Electrical power to the drive-motor may be supplied via the building&#39;s electrical system (hard-wired) or battery. For simplicity, a hard-wired connection is assumed in this document.  
         [0014]     The filter housing also contains a motor control unit used to program the frequency and length of filter advancement by regulating the electrical current supplied to the drive-motor. The frequency setting of the control unit controls how often (hours, days, weeks, months, etc.) the filter material is advanced. The length setting of the control unit controls how much filter material to advance. For example, installation in a residential HVAC unit with a twenty-inch diameter air return duct could be programmed to advance twenty inches of filter every thirty days.  
         [0015]     A filter cartridge, containing a supply container and a collection container, is placed within the filter housing. The filter material within the cartridge is advanced from the supply container (which contains clean filter material) to the collection container (which houses the used filter material) by the drive-motor of the filter housing. When the clean filter material is fully depleted, the entire filter cartridge is removed and discarded, and a new cartridge is installed.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0016]      FIG. 1 —Front view of the filter housing  
         [0017]      FIG. 2 —Top view of the filter housing  
         [0018]      FIG. 3 —Bottom view of the filter housing  
         [0019]      FIG. 4 —Back view of the filter housing  
         [0020]      FIG. 5 —Back, right angle view of filter housing  
         [0021]      FIG. 6 —Front, right angle view of filter housing  
         [0022]      FIG. 7 —Left, side view of filter housing  
         [0023]      FIG. 8 —Right, side view of filter housing  
         [0024]      FIG. 9 —Exploded, back, right angle view of filter housing showing housing lid removed from housing base  
         [0025]      FIG. 10 —Exploded view of filter cartridge  
         [0026]      FIG. 11 —Bottom view of filter cartridge  
         [0027]      FIG. 12 —Top view of filter cartridge  
         [0028]      FIG. 13 —Back view of filter cartridge  
         [0029]      FIG. 14 —Front view of filter cartridge  
         [0030]      FIG. 15 —Left, side view of filter cartridge  
         [0031]      FIG. 16 —Right, side view of filter cartridge  
         [0032]      FIG. 17 —Exploded view of filter housing and filter cartridge showing placement of cartridge within housing  
         [0033]      FIG. 18 —Top view of drive-motor  
         [0034]      FIG. 19 —Bottom view of drive-motor  
         [0035]      FIG. 20 —Front view of drive-motor  
         [0036]      FIG. 21 —Filter housing installed in-line  
         [0037]      FIG. 22 —Filter housing installed as part of coil structure  
         [0038]      FIG. 23 —Drive-Motor Control Connection to Drive-Motor 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0039]     Preferred embodiments of the present invention will be described hereinafter with reference to the accompanying drawings.  
         [0040]     Referring now to the drawings, there are disclosed preferred embodiments of the present invention. In referring to the figures of the drawings, like numerals shall refer to like parts.  
         [0041]      FIG. 1  illustrates the front view of the present invention. The invention comprises a filter housing  1  containing an opening  5 , a drive-motor  4 , a drive-motor control  2 , and a lid  7  with latches  8   a ,  8   b . The drive-motor  4  contains a power cord  3  to connect the drive-motor  4  to an electrical power source in a hard-wired configuration. The drive-motor control  2  connects to the drive-motor  4 , and controls the drive-motor by regulating the electrical current supplied to the drive-motor  4 . The drive-motor control  2  includes a keypad and other devices (such as an LED display) necessary to support interface with a human. The drive-motor control  2  also contains embedded logic, and is programmable via the keypad. Using the keypad of the drive-motor control  2 , a person can program the frequency (how often) and duration (how long) of electrical current supplied to the drive-motor  4 . For example, the drive-motor control  2  could be programmed to supply electrical current to the drive-motor  4  for forty-five seconds every thirty days.  
         [0042]      FIG. 2  and  FIG. 3  illustrate the top ( FIG. 2 ) and bottom ( FIG. 3 ) views of the present invention, which make visible flanges  9   a ,  9   b  on both the front  9   b  and back  9   a  of the filter housing  1 . These figures also illustrate the cylindrical ends  1   a ,  1   b  and rectangular mid-section  1   c  of the filter housing  1 . The rectangular mid-section  1   c  of the housing  1  is dramatically narrower than the cylindrical ends  1   a ,  1   b  of the housing  1 . The rectangular mid-section  1   c  of the housing  1  is joined tangentially to the cylindrical ends  1   a ,  1   b  of the housing  1 . The flanges  9   a ,  9   b  are used to connect the filter housing  1  ( FIG. 1 ) to the external devices used to supply air to and receive air from the filter assembly. The cylindrical ends  1   a ,  1   b  are designed to accommodate the left and right filter containers (to be described in  FIGS. 10 through 16 ).  
         [0043]      FIG. 4  illustrates the back view of the present invention in which the opening  5  of the filter housing  4  is covered by a grill  6  that is used to support filter material (to be described in  FIGS. 10, 13 , and  14 ). This figure, in combination with  FIG. 1 , makes obvious that the opening  5  passes through the entire filter assembly—meaning there is an opening on the front of the filter housing  1  in which air enters and an opening on the rear of the filter housing  1  in which air exits.  
         [0044]      FIG. 5  illustrates the back, right angle view of the present invention and reveals more clearly the rear flange  9   a  and placement of the grill  6 . The figure, as well as  FIG. 1 ,  FIG. 4 , and  FIG. 6 , illustrate that the left cylindrical end of the filter housing  1  is longer than the right cylindrical end of the filter housing, in order to accommodate the drive-motor  4 .  
         [0045]      FIG. 6  illustrates the front, right angle view and reveals more clearly the front flange  9   b  and that the grill  6  placement is on one side of the housing  1  only. In this configuration, airflow is from front to rear meaning air enters the front of the housing  1  and exits the rear of the housing. Filter material (to be described in  FIGS. 10, 13 , and  14 ) lies over a grill  6 , which supports the filter material. The filter material filters the air as the air passes through it before leaving the housing  1 .  
         [0046]      FIG. 7  and  FIG. 8  illustrate the left ( FIG. 7 ) and right ( FIG. 8 ) views of the present invention, and display the location of the latches  8   a ,  8   b  used to fasten the lid  7  to the housing  1 .  
         [0047]      FIG. 9  illustrates the back, right angle exploded view of the present invention, showing the lid  7  orientation relative to the housing  1 .  
         [0048]      FIG. 10  illustrates the rear, right angle exploded view of the filter cartridge assembly. The filter cartridge assembly comprises left  17  and right  13  filter containers that are primarily cylindrical in shape. One of the containers houses clean, unused filter material and the other container collects used filter. Determination of which container houses clean filter material and which houses used filter material is based on the location of the drive-motor  4  ( FIG. 1 ). In the present configuration, the drive-motor  4  ( FIG. 1 ) is located on the left, and therefore, the left container of the filter cartridge stores used filter material.  
         [0049]     The top and bottom of the left filter container  17  are enclosed by upper  15  and lower  18  lids. The upper  15  and lower  18  lids support an axle  16  that passes through the center of the left filter container  17 . Filter material  14  is fed from the right filter container  13  into the left filter container  17  through the rectangular, vertical opening in the container and is affixed to the axle  16 . The axle  16  rotates within the left filter container  17 , and as it rotates, used filter material is wound upon the axle  16  and stored in the left filter  17 .  
         [0050]     The top and bottom of the right filter container  13  are enclosed by upper  10  and lower  12  lids. The upper  10  and lower  12  lids support an axle  11  that passes through the center of the right filter container  13 . Clean filter material  14  is wound upon the axle  11  and is stored in the right filter container  13 . The leading end of the filter material  14  is fed from the right filter container  13  to the left filter container  17  through the rectangular, vertical opening in the right filter container  13 . The axle  11  rotates within the right filter container  13 , and as it rotates, clean filter material is unwound from the axle  11 .  
         [0051]     The lids  10 ,  12 ,  15 ,  18  are shown detached from the filter containers  13 ,  17  in this diagram for illustrative purpose only, and are intended to be affixed to the filter containers  13 ,  17  as shown in  FIG. 13  and  FIG. 14 .  
         [0052]      FIG. 11  illustrates the bottom, rear view of the filter cartridge and reveals a gear  19  attached to the base of the axle  16  ( FIG. 10 ) that passes through the center of the left filter container  17  ( FIG. 10 ). This gear  19  is designed to work with the drive-motor  4  ( FIG. 1 ) in a manner such that when the drive-motor  4  ( FIG. 1 ) rotates, the axle  16  ( FIG. 10 ) also rotates causing clean filter material to be released from the right filter container  13  ( FIG. 10 ) and used filter material to be collected in the left filter container  17  ( FIG. 10 ). The figure also reveals the location of the left lower lid  18  and right lower lid  12  in relation to the rest of the filter cartridge.  
         [0053]      FIG. 12  illustrates the top, rear view of the filter cartridge, revealing the location of the left upper lid  15  and right upper lid  10  in relation to the rest of the filter cartridge.  
         [0054]      FIG. 13  illustrates the rear view of the filter cartridge. An axle  11  is mounted vertically through the center of the right filter container  13 . An axle  16  containing a gear  19  at its base is mounted vertically through the center of the left filter container  17 . A span of filter material  14  is exposed between the left filter container  17  and right filter container  13 . The filter material  14  is affixed to both the axle  16  in the right filter container and the axle  11  in the left filter container. The gear  19  at the base of the axle  16  mounted in the left filter container  17  is designed to work with the drive-motor  4  ( FIG. 1 ). As the drive-motor  4  ( FIG. 1 ) rotates, the axle  16  in the left filter container  17  also rotates as a result of its connection to the drive-motor  4  ( FIG. 1 ) via the gear  19 . The rotation of the axle  16  in the left filter container  17  causes the filter material  14  to be wound upon the axle  16  and simultaneously causes the filter material  14  wound upon the axle  11  in the right filter container  13  to unwind.  
         [0055]      FIG. 14  illustrates the front view of the filter cartridge. An axle  11  is mounted vertically through the center of the right filter container  13 . An axle  16  containing a gear  19  at its base is mounted vertically through the center of the left filter container  17 . A span of filter material  14  is exposed between the left filter container  17  and right filter container  13 . The filter material  14  is affixed to both the axle  16  in the right filter container and the axle  11  in the left filter container. The gear  19  at the base of the axle  16  mounted in the left filter container  17  is designed to work with the drive-motor  4  ( FIG. 1 ). As the drive-motor  4  ( FIG. 1 ) rotates, the axle  16  in the left filter container  17  also rotates as a result of its connection to the drive-motor  4  ( FIG. 1 ) via the gear  19 . The rotation of the axle  16  in the left filter container  17  causes the filter material  14  to be wound upon the axle  16  and simultaneously causes the filter material  14  wound upon the axle  11  in the right filter container  13  to unwind.  
         [0056]      FIG. 15  illustrates the left, side view of the filter cartridge. A gear  19  is shown at the base of an axle  16  that passes through the center of the left filter container  17 .  
         [0057]      FIG. 16  illustrates the right, side view of the filter cartridge. An axle  11  passes through the center of the right filter container  13 .  
         [0058]      FIG. 17  illustrates the positioning of the filter cartridge (defined in  FIGS. 10 through 16 ) in relation to the filter housing (described in  FIGS. 1 through 9 ). The filter cartridge is designed to fit inside the filter housing  1  with a length of filter  14  covering the opening  5  in the filter housing  1 . Unfiltered air enters the filter housing  1  through the opening  5  in the rear of the filter housing, passes through the filter  14  which fits between the front and rear walls of the filter housing and is supported by a grate  6 , and exits, filtered, through the opening in the front of the filter housing  1 . The lid  7  encloses the top of the filter housing  1  after the filter cartridge is installed, and is secured by a left  8   a  and right  8   b  latch. The HVAC system&#39;s air-return duct supplies the air that is to be filtered, and the duct is affixed to the flange  9   a  on the rear of the filter housing  1 .  
         [0059]      FIG. 18  illustrates the top view of the drive-motor  4 . The drive-motor  4  consists of an electric motor  22  with a drive shaft that has a gear  20  affixed to it. The drive-motor  4  may be battery powered or hard-wired.  FIG. 18  assumes a hard-wired configuration, and reveals a power cord  3  that would connect the drive-motor  4  to a buildings electrical service.  
         [0060]      FIG. 19  illustrates the bottom view of the drive-motor.  
         [0061]      FIG. 20  illustrates a front, cross-sectional view of the drive-motor  4 . The illustration reveals the position of the drive shaft  21 , gear  20 , and motor windings  22 . The drive-motor  4  is affixed to the base of the left cylindrical end  1   b  ( FIG. 3 ) of the filter housing  1  ( FIG. 1 ). The gear  20  is designed to work with the gear  19  ( FIG. 13 ) on the base of the left axle  16  ( FIG. 13 ) of the filter cartridge. When electrical current is supplied to the motor, the motor rotates causing the drive shaft  21  to rotate. The drive shaft  21  is connected to the gear  20 , causing the gear  20  to rotate. The gear is designed to work with the gear  19  ( FIG. 13 ) on the base of the left axle  16  ( FIG. 13 ) of the filter cartridge thus causing the axle  16  ( FIG. 13 ) to rotate.  
         [0062]      FIG. 21  illustrates the left, side view of the entire filter housing  1  connected to the air return duct  23  of an HVAC system. In this installation configuration, the air return duct  23  is spliced and the filter housing  1  is inserted between the two halves of the duct  23 . The duct  23  is connected to the front  9   b  ( FIG. 6 ) and rear  9   a  ( FIG. 5 ) flanges of the filter housing. Air flowing through the air return duct  23  of the HVAC system is forced to pass through the filter material  14  ( FIG. 17 ) contained within the filter housing thus filtering the air as it flows from the building/structure to the HVAC heating/cooling coils.  
         [0063]      FIG. 22  illustrates an alternative installation configuration in which one side of the filter housing  1  is connected directly to the HVAC heating/cooling coils  25  and the other side is connected to the air return duct  23  of the HVAC system. Air flowing through the air return duct  23  of the HVAC system is forced to pass through the filter material  14  ( FIG. 17 ) contained within the filter housing  1 , thus filtering the air as it flows from the building/structure to the HVAC heating/cooling coils.  
         [0064]      FIG. 23  illustrates the connection of the drive-motor control  2  to the drive-motor  4  via wiring  26 . Electrical current first passes to the drive-motor control  2  before passing to the drive-motor  4 . The drive-motor control unit  2  contains embedded logic, embodied in the appropriate hardware and software, which controls the timing (frequency and duration) of electrical current supplied to the drive-motor  4 . When electrical current is supplied to the drive-motor  4 , the windings  22  are energized causing the motor to rotate. The drive-motor control  2  supports human interface via a keypad and other devices (such as an LED display) as necessary to allow a human to program the timing (frequency and duration) of electrical current supplied to the drive-motor  4 , ultimately controlling the timing of advancement of filter material  14  ( FIG. 17 ).