Background of the Invention [0001] This invention relates to a media filter cabinet for installation in a ducted system that has been modified either at the time of installation or sometime thereafter so that the system can provide both heating and cooling. [0002] Currently, dealers and distributors who install or modify existing ducted systems so that the system can provide both heating and cooling find difficulty in installing a filter cabinet into the system because of the presence of the fan coil unit at the entrance to the return air duct. Attempts to alter existing cabinets such as that described in U.S. Patent No. 6,502,909 to Swilik, Jr. et al., have not proven to be very successful because the existing cabinets are of a different dimension than that required in a ducted system equipped with a fan coil unit. Accordingly, any needed alteration is work intensive, time consuming, and costly. In addition, a relatively large number of fasteners are generally required to properly mount the altered cabinet particularly with regard to the return air duct of the system. [0003] A number of after market cabinet suppliers manufacture cabinets that provide a better fit than the modified cabinets, however, these after market products still require a certain amount of refinement before they fit properly into the system again wasting a good deal of time and effort on the part of the installer.

Summary of the Invention [0004] It is therefore a primary object of the present invention to improve fan coil media cabinets. [0005] It is a further object of the present invention to more precisely fit a media cabinet filter into a ducted system that is equipped with a fan coil unit. [0006] It is a still further object of the present invention to reduce the time and effort required to install a media filter cabinet in a ducted system that is equipped with a fan coil unit. [0007] Another object of the present invention is to reduce the number of parts and fasteners needed to install a media filter cabinet to a fan coil unit. [0008] These and other objects of the present invention are attained by a media filter cabinet for use in association with the fan coil unit of a ducted system. The cabinet includes a drop in open-sided inner liner containing top and bottom panels that are co-joined by front and back panels. The inner liner is mounted within an outer shell that encompasses the top panel, bottom panel, and back panel of the inner liner whereby air can flow freely through the opposed sides of the assembly. The shell is rigidly mated to the return air opening of the fan coil unit, so that the front panel of the inner liner remains accessible. The front panel contains an access door having an opening through which a media filter can be inserted into or removed from the inner liner. The inner liner rests upon flanges located along one edge of the shell and is secured in place using a minimum number of fasteners. A space is provided between the walls of the shell and the adjacent panels of the inner liner and a fiberglass insulation blanket is mounted within the space. The door to the inner liner is also provided with insulation to further limit the exchange of energy between the interior of the cabinet and the surrounding ambient.

Brief Description of the Drawings

[0009] For a better understanding of these and other objects of the present invention, reference will be made to the following detailed description of the invention, which is to be read in association with the accompanying drawings, wherein: [00010] Fig. 1 is a perspective view showing a filter media cabinet attached to the return air opening of a fan coil unit; [00011] Fig. 2 is a perspective view showing the inner liner of the cabinet assembled within the outer sleeve of the cabinet; [00012] Fig. 3 is a further perspective view showing the outer sleeve of the cabinet in greater detail; and [00013] Fig. 4 is an exploded view in perspective showing the inner liner of the cabinet in greater detail. Detailed Description of the Invention

[00014] Referring now to Figs. 1-4, there is illustrated a media filter cabinet, generally referenced 10, that embodies the teachings of the present invention. The cabinet is arranged so that it can be rigidly secured to the return air opening 11 of a fan coil unit. The cabinet is mounted in the return air duct of a ducted system directly to the inlet of a fan coil unit. The cabinet is adapted to slideably receive therein a high efficiency media filter 13. Such high efficiency type air filters are referred to as media filters because they contain a number of different filtering media each of which acts upon the air passing through the filter to remove a wider number of air borne contaminants when compared to earlier single medium filters. [00015] The present cabinet includes an inner liner 15 that is contained within an outer shell 16. The inner liner, which is shown in greater detail in Fig. 4 is constructed in the manner described in U.S. Patent No. 6,502,909 to Swilik, Jr. et al., the teachings of which are incorporated herein by reference. The inner liner contains a back panel 20, a top panel 21 , a bottom panel 22, and a front panel 23 that contains a pair of spaced apart cross brackets 24 and 25 that define a door opening. The panels are brought together as explained in the Swilik, Jr. et al. patent to form an open-sided rectangular frame. The connecting sheet metal parts utilized in the Swilik, Jr. et al. patent are provided with tabs and cutouts so that tabs of one panel can be mated with a cutout in an adjacent panel and the tabs then bent over to join the parts in assembly. It should be understood, however, other forms of connectors may be also employed without departing from the teachings of the present invention, as for example, self-tapping sheet metal screws or other types suitable threaded fasteners known and used in the art. [00016] The door opening of the inner liner is dimensioned so that media filters having a width up to five inches may be inserted into and removed from the liner through the door opening. As illustrated in Fig. 4, the brackets 24 and 25 are secured to the top and bottom panels of the inner liner using sheet metal screws, 26. A door 27 is removeably secured to the inner liner by means of top and bottom bayonet connectors, which include a female member 28 that is arranged to mate with a male member 29 (Fig. 1). Although bayonet type connectors are shown in Fig. 1, any suitable type of connector for removeably securing the door to the frame may be employed without departing from the teachings of the invention. [00017] A pair of parallel spaced apart guide rails 30 and 31 are integrally formed in the top and bottom panels of the inner liner for directing the media filter into and out of the liner and for properly positioning the media filter within the liner. A stop rail 33 is also secured upon the back panel of the inner liner which further helps to position the media filter within the inner liner. [00018] As noted above, attempts have been made to modify existing gas furnace media filter cabinets of the type described in the Swilik, Jr. et al. patent for use in association with ducted systems that are equipped with fan coil units. These attempts for the most part have been unsatisfactory for a number of reasons. The Swilik et al. type cabinet is not dimensionally compatible for use in most fan coil applications and must be altered considerably when used within a ducted system equipped with a fan coil. The overall structure of the Swilik et al. cabinet is relatively weak, and as a consequence, a relatively large number of fasteners are required to mount the modified cabinet to system. [00019] To overcome these and other difficulties, the inner liner of the present cabinet is mounted within a three-sided outer shell generally referenced 16, which is shown in detail in Fig. 3. The shell is relatively simple in construction and is fabricated from a single sheet of sheet metal that is bent to form a top wall 41 and a bottom wall 42 that are co-joined by a back wall 43. The side edges of each wall are bent inwardly perpendicular to the plane of the wall to establish a ledge 45 that extends around the perimeter of the outer shell. In assembly, the inner liner is simply dropped into the sleeve so that the top panel, the bottom panel, and the back panel rest upon the ledge. The inner liner is then joined to the shell using four sheet metal screws 26-26 that pass through the brackets in the front panel of the inner liner and are threaded into receiving holes 48-48 contained in the top and bottom panels of the inner liner. Although not shown, rivets might also be used to join the ledge of the shell to adjacent panels of the inner liner. It has been found that two rivets along with the four above mentioned screws are sufficient to establish a extremely rigid cabinet structure. [00020] As illustrated in Fig. 2, the walls of the outer shell have a greater width than the width of the adjacent panels and thus protrude to one side of the inner liner when the inner liner is seated upon the ledge of the shell. In assembly, the extended sections of the sleeve wall are arranged to pass over the return duct of the furnace and are secured to the duct walls to sheet metal screws 49-49 (Fig. 1). Screw holes 51 are provided in the extended sections of the shell walls for this purpose. When secured to the return duct, the access door of the cabinet can be freely opened and closed to facilitate replacement of the media filter 40. The fan coil is then mounted adjacent to the open side of the cabinet and is fastened in place using the existing fan coil fastener. [00021] In assembly, a space is provided between the walls of the sleeve and the adjacent panels of the inner liner. This space is filled with an insulating material 53, such as fiberglass or the like to prevent the transfer of energy between the cabinet and the surrounding ambient. Similarly, the door also contains a strip of insulating material 54 to further help prevent the exchange of energy between the cabinet and the surrounding ambient. [00022] While this invention has been particularly shown and described with reference to the preferred embodiment in the drawings, it will be understood by one skilled in the art that various changes in its details may be effected therein without departing from the teachings of the invention.