Abstract:
An air filtering and freshening device comprising a filter element within the intake of the device housing, a motorized fan mounted within the device housing which draws contaminated air into the device, and forces air out of the device through an outlet having separate exhaust and scent discharge passages. The exhaust passage including a plurality of arcuate vanes radiating outwardly from the interior of the device, and being disposed across the exhaust passage to promote efficient operation by reducing the pressure drop through the passage and minimizing operational noise. The scent discharge passage includes a scent element producing a freshening scent. The scent element is removably positioned adjacent the scent discharge passage, which carries high velocity, high pressure filtered air from the motorized fan, picks up the concentrated freshening scent, and discharges in an effective and efficient manner, a continuous stream of freshening scent.

Description:
INCORPORATION BY REFERENCE 
     Johnson, U.S. Pat. No. 4,252,547; Barradas, U.S. Pat. No. 5,735,918; and Cartellone, U.S. Pat. No. 5,837,020 are incorporated herein by reference, so that background art relating to air filtering and freshening devices need not be described in detail herein. 
     BACKGROUND OF THE INVENTION 
     This invention relates to the art of air filtering devices and, more particularly, to devices which both filter pollutants from contaminated air and introduce a freshening scent to the filtered air. 
     Air filtering and freshening devices have been provided heretofore and generally, as shown in patents to Barradas (U.S. Pat. No. 5,735,918) and Johnson (U.S. Pat. No. 4,252,547) for example, have a fan for moving air through the device, a filtering element for removing pollutants from contaminated air, and a freshening device for adding a scent to the air. These existing devices also include a housing, within which each of the other components is situated. In the air filtering and freshening devices provided heretofore, the relative position of each of the components in the housing has led to inefficient and ineffective performance of these devices. 
     For example, in Barradas the fan is positioned within the housing upstream of the filter element. That is, the fan pushes the air into and through the filter element. As a result, the air exiting the filter element has a relatively low velocity and therefore does not circulate effectively. Furthermore, as the filter element becomes increasingly filled with contaminants, it is increasingly difficult for air to pass through the device. This means that the velocity of the already low velocity air being discharged from the device is further reduced as the filter element becomes increasingly dirty. Furthermore, the scent discharged in Barradas is fed by both filtered and unfiltered air due to its position in the housing relative to the filter element. As a result of this dual air feed, some contaminated or unfiltered air is output by the device. As the filter element becomes increasingly dirty and it becomes increasingly more difficult for air to pass through, so more and more unfiltered air is fed to the scent discharge and recycled into the surrounding air. Another problem with positioning the fan before the filter element is that this results in dirt and dust collecting on the motor and which dramatically reduces its service life. Finally, air flows from areas of higher pressure to areas of lower pressure. By positioning the fan upstream of the filter element, Barradas uses atmospheric pressure as the lower pressure area. Barradas therefore requires the fan to generate high pressure air having a value greater than the atmospheric pressure plus the pressure loss across the filter element. Otherwise, no air will flow through the device. This is an inefficient arrangement which creates power requirements significantly higher than are necessary. 
     In contrast to Barradas, Johnson positions the fan downstream of the filter elements. This makes for a more efficient use of the fan by utilizing atmospheric pressure to induce flow of air to the low pressure area created by the fan on the other side of the filter element. This arrangement also permits filtered air rather than unfiltered air to pass across the motor, eliminating the dirt and dust build up which shortens motor life. However, Johnson, like Barradas, does allow some unfiltered air to pass through and be output by the device. Converse Barradas, which has a single intake passage and dual output passages, Johnson has dual intake passages that feed a single output chamber. The first of the Johnson intakes is through a filter element in the conventional manner. The second intake flows parallel to the first but does not include a filter element. The second air intake allows air to flow into a scent chamber without being filtered. The freshened scent is introduced to the unfiltered air in the chamber and then the air is discharged into a main exhaust chamber which also contains filtered air that is flowing toward the output. 
     Along with the circulation of unfiltered air, another problem left unresolved by the device of Johnson is the ineffective discharge of the freshening scent. As discussed above, the device in Johnson draws unfiltered air into and through the scent chamber. The freshened air is then drawn into an exhaust chamber where it may get caught in an eddy which could retain the air in the device, or it may be diffused into the surrounding air, or it may be immediately expelled in its concentrated form. As the flow of air within the device dynamically changes, the freshened air will likely move between each of these three discharge flows. As a result, the scent output of the device in Johnson is not consistent, and a scent output control will not be effective in controlling the output of the freshening scent. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, an air filtering and freshening device of the foregoing character is provided which avoids or minimizes the problems and inefficiencies encountered with the use thereof. More particularly in this respect, an air filtering and freshening device is provided which effectively and efficiently produces filtered and freshened air without recycling any unfiltered air. Furthermore, the air filtering and freshening device of the subject invention discharges freshened air in a consistent and effective manner which is responsive to the scent discharge control baffle. 
     The subject invention provides a motorized fan within the housing of the air filtering and freshening device that “pulls” contaminated air through the filter element and into the housing by creating a lower pressure area inside the housing, adjacent the filter element. The higher pressure of the atmosphere outside the housing causes contaminated air to flow through the filter element to the lower pressure area within the housing, thereby filtering the contaminated air. This is an efficient use of the naturally occurring atmospheric pressure, which utilizes this pressure to create flow through the device rather than working to create flow against the atmospheric pressure. The fan then “pushes” the filtered air out of the outlet of the housing through both an exhaust passage and a scent discharge passage. 
     Both the exhaust and scent discharge passages are in direct fluid communication with the motorized fan, whereby the flow of filtered and freshened air from the respective passages is not affected by the condition of the intake filter element in the drastic manner that prior filtering devices have been. Furthermore, the filtered air is “pushed” through the freshening device by the fan providing high velocity, filtered air concentrated with scent to be output through the scent discharge passage. This scented air is then dispersed into the surrounding atmosphere in a consistent and effective manner, regulated only by the control baffle, and without being influenced by the condition of the filter element or an inefficient flow through the house. The scent output is further enhanced by the provision of a heating element adjacent the scent element which increases the concentration of scent output. 
     Due to the increased effectiveness of the freshening device and the desire to maintain such effectiveness, the regular replacement of the scent element is important. Accordingly, the subject invention provides easy access to the scent element which can be removed and replaced without the use of tools. The scent element is secured within a drawer which is spring biased toward an ejected position, in which the scent element is accessible and easily replaced. By pushing the drawer against the spring bias, the drawer will return to a retracted position in which the replaced scent element is again in position to dispense freshening scent into the flowing air. If the drawer is pushed against the bias of the spring a second time, the drawer will release and the spring will bias the drawer toward the ejected position, again providing access to the scent element. As previously indicated, this is accomplished without the use of or need for tools. 
     Accordingly, it is one of the main objects of the present invention to provide a high efficiency air filter having a freshening device therein which can be adjusted to control the scent output without restricting the exhaust of filtered air. 
     Another object of the present invention is the provision of an air filtering and freshening device in which the volumetric flow of scented air is not directly influenced by the condition of the filter element. 
     Still another object of the present invention is the provision of an air filtering and freshening device in which the freshening device has simple controls that can be easily adjusted between a no output position and a full output position. 
     A further object of the invention is the provision of an air filtering and freshening device having a scent element within the freshening device which is easily accessible and replaceable without the use of or need for tools. 
     Yet another object of the invention is to provide an air filtering and freshening device in which the effectiveness of the scent freshening element is improved. 
     A further object is the provision of an air filtering and freshening device which is comprised of a minimum number of parts and is structurally simple, thereby promoting economical production of the device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing objects, and others, will in part be obvious and in part pointed out more fully hereinafter in conjunction with the written description of preferred embodiments of the invention illustrated in the accompanying drawings in which: 
     FIG. 1 is a perspective view of one embodiment of an air filtering and freshening device in accordance with the present invention; 
     FIG. 2 is a sectional elevation view taken along line  2 — 2  in FIG. 1; 
     FIG. 3 is a partial sectional top plan view taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a cross-sectional elevation view taken along line  4 — 4  in FIG. 3; 
     FIG. 5 is a cross-sectional elevation view taken along line  5 — 5  in FIG. 3; 
     FIG. 6 is a cross-sectional elevation view taken along line  6 — 6  in FIG. 3; 
     FIG. 7 is a bottom plan view of the latch mechanism shown in FIG. 3; 
     FIG. 8 is an exploded perspective view of the drawer, latch mechanism, and scent element shown in FIG. 3; 
     FIG. 9A is a cross-sectional, bottom plan view of the drawer, latch mechanism, and scent element taken along line  9 — 9  in FIG. 4, and showing the drawer, latch mechanism, and scent element retracted with the latch plate laterally positioned; 
     FIG. 9B is a cross-sectional, bottom plan view of the drawer, latch mechanism, and scent element taken along line  9 — 9  in FIG. 4, and showing the drawer, latch mechanism, and scent element depressed and the latch mechanism centered; 
     FIG. 9C is a cross-sectional, bottom plan view of the drawer, latch mechanism, and scent element taken along line  9 — 9  in FIG. 4, and showing the drawer, latch mechanism, and scent element released and the latch mechanism ejecting the drawer; 
     FIG. 9D is a cross-sectional, bottom plan view of the drawer, latch mechanism, and scent element taken along line  9 — 9  in FIG. 4, and showing the drawer, latch mechanism, and scent element released toward the ejected position; 
     FIG. 9E is a cross-sectional, bottom plan view of the drawer, latch mechanism, and scent element taken along line  9 — 9  in FIG. 4, and showing the drawer, latch mechanism, and scent element depressed toward the retracted position; 
     FIG. 9F is a cross-sectional, bottom plan view of the drawer, latch mechanism, and scent element taken along line  9 — 9  in FIG. 4, and showing the drawer, latch mechanism, and scent element depressed toward the retracted position with the latch mechanism transversely positioned; 
     FIG. 10 is a cross-sectional top plan view taken along line  10 — 10  in FIG. 2; and, 
     FIG. 11 is a cross-sectional elevation view taken along line  11 — 11  in FIG.  10 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now in greater detail to the drawings, wherein the showings are for the purpose of illustrating preferred embodiments of the invention only, and not for the purpose of limiting the invention, FIGS. 1 and 2 of the drawings illustrate an air filtering and freshening device  10  having a lower housing portion  12  and an upper housing portion  14 . Lower housing portion  12  includes a base  16  having a bottom surface  18  resting upon the floor of an interior space of a building; filter support surface  20  parallel with but spaced away from bottom surface  18 ; an outside radial wall  22  extending upwardly from filter support surface  20  in the direction away from bottom surface  18 ; an inside radial wall  24  spaced radially inwardly from outside radial wall  22 ; and a guide surface  26  in the center of base  16  extending to inside radial wall  24  and having a hole  28  axially therethrough. 
     Resting on filter support surface  20  is a screen  30  of cylindrical shape having a screen outside surface  32  that fits within inside radial wall  22 . Screen  30  has a relatively limited thickness forming a screen inside surface  34  having a diameter slightly less than screen outside surface  32 . Screen material is well known, and is available in a wide variety of sizes and constructions, and therefore will not be further described hereinafter except to indicate that the construction of the screen material and the relative size of mesh holes  36  should be selected based on the application and atmosphere in which the device will operate. In making such a selection, mesh holes  36  should be of sufficient size that air can pass relatively freely through the screen yet mesh holes  36  should be small enough to prevent larger objects from passing through the screen and damaging the filter element  38 . 
     Filter element  38  is cylindrical in shape having a filter outside surface  40  and a filter inside surface  42 . Filter element  38  extends axially from a first filter end  44  to a second filter end  46 . Filter element  38  fits axially within screen  30  so that first filter end  44  is resting on and supported by filter support surface  20 , and filter inside surface  42  is adjacent inside radial wall  24 . Filter element  38  can be constructed of any one, or more than one, of a wide variety of particle filter materials depending on the application in which the filter is intended to operate. Filter materials of this kind are well known, and therefore will not be further described hereinafter. However, a supplemental carbon filter  48  can be optionally fit axially within and adjacent filter inside surface  42  of filter element  38  to further remove smoke and other gas particles. 
     Filter element  38  is axially captured between filter support surface  20  adjacent first filter end  44 , as previously indicated, and motor mount support surface  52  which is axially adjacent and supported by second filter end  46  of filter element  38 . Motor mount support surface  52  extends radially outwardly from the center of motor mount  50 , and is connected to motor support surface  54  by a transfer structure  56  which extends therebetween. Transfer structure  56  consists of two generally axially extending cylindrical transfer walls  58  and  60  connected by a bottom  62  which extends radially therebetween. Transfer wall  60  is connected to motor mount support surface  52 , and transfer wall  58  extends from motor support surface  54 . Both transfer walls  58  and  60  have a series of transfer passages  64  extending therethrough which permit incoming filtered air in the lower housing portion  12  to be in fluid communication with upper housing portion  14 . Recessed axially from motor support surface  54  is tension rod surface  66  which has a hole  68  axially therethrough. Tension rod  70  passes through hole  68  and tension rod surface  66  and extends into hole  28  in guide surface  26  of base  16 . End cap  72  of tension rod  70  is forced against tension rod surface  66  as a knob  76  is threaded onto the threaded end  74  of tension rod  70 , thereby tensioning tension rod  70  and compressibly capturing filter element  38  between filter support surface  20  and motor mount  25  support surface  52 . 
     Upper housing portion  14  extends from motor mount  50  and includes a motor  78 , a centrifugal fan  80  driveably connected to motor  78 , and a cover  82 . Motor  78  is attached to motor support surface  54  by a plurality of threaded mounting studs  90  which extend through corresponding mounting holes  88  and are secured by threaded nuts  92 . Motor  78  has a drive shaft  94  extending axially therefrom in the direction opposite to threaded mounted studs  90 . Centrifugal fan  80  has a hub  96  driveably attached to drive shaft  94 . Hub  96  is connected to upper rim  98  of centrifugal fan  80 . Lower rim  100  is axially spaced from upper rim  98  toward motor  78 , and a plurality of fan blades  102  extend therebetween in a radial pattern coaxial with hub  96 . 
     Cover  82  is axially spaced away from motor  78  in the direction opposite base  16 , and has a cover exterior surface  104 , a cover interior surface  106 , and a baffle mounting plate  110  which is adjacent upper rim  98  of centrifugal fan  80 . The exterior and interior surfaces  104  and  106  of cover  82  provide a generally curvilinear thin-walled shell that terminates at cover rim  108 . Baffle mounting plate  110  is attached to cover  82  adjacent cover rim  108 , defining a cavity  112  between cover interior surface  106  and baffle mounting plate  110 . 
     As previously discussed, cover  82  is axially spaced away from motor mount  50  such that baffle mounting plate  110  is adjacent upper rim  98  of centrifugal fan  80 . On the opposite side of motor mount support surface  52  on motor mount  50  is a radially extending vane mount surface  114 . A plurality of outwardly radiating arcuate vanes  116  extend axially from baffle mounting plate  110  and are attached to vane mount surface  114  of motor mount  50 . As is more clearly shown in FIG. 10, arcuate vanes  116  each have a leading edge  118  and the trailing edge  120 . Leading edges  118  are equidistantly disposed around the perimeter of centrifugal fan  80 . Trailing edges  120  of arcuate vanes  116  are positioned radially outwardly of leading edges  118  and are equidistantly spaced adjacent the perimeter of vane mount surface  114  and baffle mounting plate  110 . As is more fully discussed in Cartellone (&#39;020), which has been incorporated herein by reference, the length, curvature, and quantity of arcuate vanes  116  in any particular embodiment of the subject device will depend on the overall size of the outside diameter of the air filtering and freshening device  10  and the output capacity for which the device was designed. The flow of the filtered air between arcuate vanes  116  as the air is output by device  10  is more fully described hereinafter. 
     As can be appreciated from the discussion hereinbefore, centrifugal fan  80  “pulls” contaminated air into air filtering and freshening device  10  through filter element  38 , and then “pushes” the filtered air out of the device  10  through exhaust passage  84  and scent discharge passage  86 . Exhaust passage  84  extends radially from the periphery of centrifugal fan  80  and is axially defined by baffle mounting plate  110  and vane mount surface  114  of motor mount  50 . Exhaust passage  84  is made up of a plurality of individual passages corresponding to and defined as the space between arcuate vanes  116 . The filtered air is “pushed” by centrifugal fan  80  uniformly through each of the individual passages, collectively defining exhaust passage  84 , so that the filtered air flows along both concave side  122  and convex side  124  of each of the arcuate vanes  116 . However, as the filtered air is forced radially outwardly by blades  102  of centrifugal fan  80  the filtered air is compressed against the concave side  122  of arcuate vanes  116 . This action creates high pressure filtered air that travels radially along the concave side  122  of arcuate vanes  116  until the air reaches the leading edge  118  of the next adjacent arcuate vane  116 . After the filtered air travels beyond the leading edge  118  of the next adjacent arcuate vane  116 , the high pressure filtered air thereafter travels between the radially extending arcuate vanes  116  until the air is discharged from device  10 . As the air travels between the two adjacent arcuate vanes  116 , the high pressure air expands as the adjacent arcuate vanes  116  move further apart, decreasing the air pressure and increasing its velocity. This results in high velocity air being discharged from air filtering and freshening device  10  through exhaust passage  84 . At any point along the flow of air between adjacent arcuate vanes  116  of exhaust passage  84 , a pressure and velocity gradient will exist transverse to the direction of flow. Diversion channel  126 , more fully described hereinafter, should be positioned relative to arcuate vanes  116  so that high pressure and high velocity air can be diverted into scent chamber  132 , thereby improving the effectiveness of scent discharge passage  86 . 
     As is more clearly shown in FIGS. 2,  10  and  11 , scent discharge passage  86  is fed by a portion of the filtered air being expelled through exhaust passage  84 . Diversion channel  126  extends from the fan side of baffle mounting plate  110  into one of the individual passages of exhaust passage  84 . Diversion channel  126  has a bottom surface  128  which extends from baffle mounting plate  110  at an acute angle forming a ramp, which diverts filtered air flowing through exhaust passage  84  up the ramp and through baffle plate opening  130 , which defines the beginning of scent passage  86 , and into scent chamber  132 . Extending from bottom surface  128  of diversion channel  126  is channel wall  134 . As can be appreciated, diversion channel  126  is defined by bottom surface  128  and may have a channel wall projecting from each side of bottom surface  128  and extending to baffle mounting plate  110 . Alternatively, as is shown in FIGS. 10 and 11, bottom surface  128  may be adjacent one of the sides  122  or  124  of one of arcuate vanes  116 . In such an embodiment, arcuate vane  116  defines the second wall of diversion channel  126  opposite channel wall  134 . Irrespective of the particular embodiment of diversion channel  126 , as discussed immediately above, the channel will terminate at baffle mounting plate  110  adjacent at least a portion of baffle plate opening  130  so that diverted air will be in fluid communication with scent chamber  132 . 
     The amount of air diverted which can be channeled through scent discharge passage  86  is directly controlled by baffle  136 , best shown in FIGS. 3,  6 ,  10 , and  11 . Baffle  136  is slidable between a first position in which the baffle plate opening  130  is largely uncovered, and a second position in which the baffle plate opening is fully covered. Baffle  136  is infinitely adjustable between the first and second positions, providing control over the amount of air flowing through baffle plate opening  130  and into scent chamber  132  and through scent discharge passage  86 . 
     Scent chamber  132  extends between baffle mounting plate  110  and cover interior surface  106  of cover  82 . However, scent chamber  132  is partitioned from cavity  112 , also defined therebetween, by chamber wall  138  which defines three sides of the scent chamber. The top and fourth side of scent chamber  132  are defined by cover interior surface  106  of cover  82 , and the bottom of scent chamber  132  is defined by baffle mounting plate  110 . As is best shown in FIGS. 1 and 4, scent discharge passage  86  ends at cover discharge opening  140  which extends through cover  82  adjacent scent chamber  132 . Extending across covered discharge opening  140  is a plurality of louvers  142 . 
     As previously discussed, a portion of the filtered air flowing through exhaust passage  84  is diverted by diversion channel  126 , and enters scent discharge passage  86  through baffle plate opening  130 , the functional size of which may be reduced by baffle  136 . The air entering scent chamber  132  circulates around the chamber as the air is pushed up toward and out of cover discharge opening  140 . As the air swirls and circulates through scent chamber  130 , the air picks up a freshening scent which is being produced by scent element  144 . Drawer  146  is slidably positioned within scent chamber  132 , and contains scent element  144 . Drawer  146  is slidable between a retracted position, in which drawer  146  and scent element  144  are secured within scent chamber  132 , and an ejected position in which drawer  146  and scent element  144  are extending out of upper housing portion  14 . With drawer  146  in the ejected position, scent element  144  is accessible such that a used scent element can be easily removed from drawer  146  and replaced with a new scent element. 
     As is best shown in FIGS. 7,  8 , and  9 A- 9 F, drawer  146  has a front end  148 , a latch end  150  opposite the front end, a pair of spaced apart sides  152 , a top  154 , and a bottom  156 . Extending vertically from top  154  are retaining walls  158  which form scent element cavity  160  adjacent top  154  of drawer  146 . Front end  148  is adjacent and flush with cover exterior surface  104  of cover  82  when drawer  146  is in the retracted position. Bottom  156  of drawer  146  is oriented toward, but spaced away from baffle mounting plate  110 . Drawer  146  is longitudinally slidably supported by drawer supports  162  which are positioned adjacent sides  152 , and which retain drawer  146  preventing lateral and vertical movement relative to baffle mounting plate  110 . Latch end  150  of drawer  146  has two plate retaining tabs  180  projecting from top  154  of drawer  146  at latch end  150 . Additionally, two spring reaction walls  164  extend longitudinally from latch end  150  toward front end  148 , and retaining barb  166  is centered therebetween at latch end  150 . Latch plate  168  has a tab end  170  and a spring end  172 , and is oriented such that tab end  170  is toward front end  148  of drawer  146 . Latch plate  168  has a laterally oriented plate retaining slot  174  with two laterally oriented deflection slots  176  longitudinally positioned adjacent retaining slot  174 , forming deflection bars  178  therebetween. Latch plate  168  is attached to latch end  150  of drawer  146  by positioning tab end  170  underneath plate retaining tabs  180 , and forcing plate retaining slot  174  over retaining barb  166 . Deflection bars  178  are forced away from plate retaining slot  174  and into deflection slots  176 , allowing retaining barb  166  to pass through plate retaining slot  174  before returning to an undeflected position thereby preventing the removal of latch plate  168 . A first spring  182  is attached to and acts to transversely bias latch plate  168  by acting against spring reaction wall  164 . A second spring  184  is attached to latch plate  168  opposite first spring  182  and acts to transversely bias latch plate  168  in the opposite direction from first spring  182  by acting on a second spring reaction wall  164 . As a result of the bias of both springs acting opposite each other, latch plate  168  can slide laterally along plate retaining slot  174  in either lateral direction, but latch plate  168  will return to the transverse center of drawer  146  as the spring biases balance against one another. Latch plate  168  includes a third spring  186  attached at the spring end  172 . Third spring  186  biases drawer  146  toward an ejected position by acting against a spring reaction wall  188  extending from baffle mounting plate  110 . In a preferred alternative spring construction, spring  186  is replaced by two leaf spring, one extending from the top spring  182  and one from the top of spring  184 . These leaf springs converge at bulbous ends riding on reaction wall  188 . This reduces the transverse frictional force between the spring construction and reaction wall  188 . Latch plate  168  has a first boss  190  and a second boss  192  protruding downwardly therefrom. Projecting upwardly from baffle mounting plate  110  is latch post  200  which is positioned adjacent first and second bosses,  190  and  192  respectively, when drawer  146  is in the retracted position. 
     A previously discussed object of the subject invention is the provision of an air filtering and freshening device  10  in which scent element  144  can be easily accessed and replaced without the need for tools. FIGS. 9A-9F illustrate a mechanism by which this object is accomplished. FIG. 9A shows a bottom view of drawer  146  secured in retracted position with latch post  200  engaging holding portion  198  of second boss  192 , preventing the ejection of the drawer. In this position, latch plate  168  is biased from center in the direction of arrow A, compressing first spring  182 . Additionally, the longitudinal position of drawer  146  and latch plate  168  when latch post  200  is engaging holding portion  198  requires that third spring  186  be compressed against spring reaction wall  188 . 
     To eject drawer  146  from within scent chamber  132 , drawer  146  must be depressed into scent chamber  132 , as indicated by arrow B 1 , until latch end  150  contacts drawer stops  202 , as shown in FIG.  9 B. This action moves holding portion  198  of second boss  192  longitudinally away from latch post  200 , allowing compressed first spring  182  to center latch plate  168  on drawer  146 , as indicated by arrow B 2 . First boss  190  is positioned longitudinally adjacent second boss  192  opposite holding portion  198 . As drawer  146  is forced into scent chamber  132 , first boss  190  assists first spring  182  in moving latch plate  168  to a center position in which latch post  200  is laterally adjacent second boss  192 . At this point, as can be in FIGS. 9C and 9D, the depression force is eliminated, and third spring  186  biases drawer  146  toward the ejected position, as indicated by arrow C 1 , during which time, ejecting portion  196  of second boss  192  can pass beside or slide against latch post  200 . As is best shown in FIG. 9C, ejecting portion  196  of second boss  192  compresses second spring  184 , as indicated by arrow C 2 , as ejecting portion  196  slides past latch post  200 . As is then shown in FIG. 9D, as drawer  146  moves toward the ejected position, as indicated by arrow D, and the influence of latch post  200  on ejecting portion  196  has been discontinued, the compressive force on second spring  184  has dissipated and latch plate  168  has been again centered on drawer  146  as the bias forces of second spring  184  and first spring  182  balance against each other. 
     Having been ejected from scent chamber  132  and with scent element  144  replaced, drawer  146  is depressed toward the retracted position, as is shown in FIG.  9 E and indicated by arrow E, in which latch post  200  will be positioned longitudinally adjacent holding portion  198  of second boss  192 , shown in FIGS. 9F and 9A. As indicated by arrows E and F, of FIGS. 9E and 9F respectively, retracting portion  194  of second boss  192  approaches and slideably engages latch post  200  as drawer  146  moves toward the retracted position. Correspondingly, this movement laterally biases latch plate  168  compressing first spring  182  as indicated by arrow F 2  of FIG.  9 F. Retracting portion  194  slides along latch post  200  until reaching holding portion  198 , at which point the biasing force from retracting portion  194  dissipates. Compressed first spring  182  will attempt to relieve the compression force by moving latch plate  168  toward the center of drawer  146 , and thereby causing holding portion  198  of second boss  192  to engage latch post  200 . Furthermore, as drawer  146  is being longitudinally depressed into the retracted position, third spring  186  will contact spring reaction wall  188  slightly compressing third spring  186  in preparation for the next ejection cycle, beginning again with FIG.  9 A. 
     To further enhance the effectiveness and output of scent discharge passage  86 , a heating element  204  is positioned subjacent scent element  144  and drawer  146 , as shown best in FIGS. 4 and 5. Heating element  204  receives electric current through wire  206  which causes an increase in the temperature of heating element  204  in a conventional manner. Heating element  204  warms scent element  144  increasing the freshening scent output therefrom. The increased freshening scent is carried out of the scent chamber  132  through cover discharge opening in the manner describe hereinbefore, increasing the overall effectiveness of scent discharge passage  86 . 
     Heating element  204  receives electric current through wire  206 , as previously described. The current is controlled through heater switch  208 , as can best be seen in FIGS. 1 and 2. Heater switch  208  is electrically connected to control box  214 , which includes fan speed control  210 . Control box  214  receives electrical power through electrical cord  216  which is adaptable to connect to a typical electrical receptacle (not shown) using a typical electrical plug (not shown). Between control box  214  and the electrical plug, electrical cord  216  connects with motor  78 , and also includes a filter change plug  212 . As filter element  38  becomes dirty and contaminated, it is necessary to separate the upper housing portion  14  from lower housing portion  12  to replace filter element  38 . A filter change plug  212  can be used to disconnect the electrical cord  216 , as is further described in Cartellone (&#39;020). However, electrical cord  216  may also be wired directly into upper housing portion  14  obviating the need for filter change plug  212 .