AIR DRIVER FRAME DESCRIPTION OF THE INVENTION The invention relates to a rectangular structural frame for a module for an air handling unit, having all the outer surfaces formed from a non-corrosive material. Residential and commercial air conditioners include air handling units that include as a part thereof a heat exchanger and a fan, which cooperate to direct the air that is heated and / or cooled through the heat exchanger for the air. direction to an enclosed area that is heated and / or cooled. It is well known to manufacture said air handling units in a modular form, wherein the modular units have common dimensions, which allow them to be assembled in a variety of combinations depending on the size of the installation and the location of the installation. The basic modules of said system include a fan module, which typically includes a centrifugal motor and fan assembly, a coil module, which includes a heat exchanger coil and filter modules. Typically, the modular construction includes a substantially rectangular frame, which supports the interior components of the module and supports the outer walls for enclosing the components. It is known in the prior art to define the structural frame by the use of eight corner adapters which are each adapted to receive three of the free ends of the eight structural elements that extend horizontally and four vertically to define with this a supporting frame rigid solid rectangular This frame is adapted to receive in a removable form and support the outer wall panels as required for the particular construction of the module, i.e., a fan module, a coil module or a filter module. The horizontal and vertical elements for said modular construction are typically formed from aluminum extrusions. Said metal components establish a heat transfer path between the interior of an air handling module and the exterior thereof. Said heat transfer path will result in loss of unit efficiency and also, during the air conditioning mode, will result in condensation of warm moisture air on the outer surfaces of the metal components. Condensed moisture and exterior components will corrode the components and may cause damage to adjacent structures or components. Accordingly, it is desirable to have air handling modules in which all components are non-corrosive and have a non-direct metal-to-metal path from the interior to the exterior thereof. The invention relates to a rectangular frame for a module for an air handling unit. The frame comprises eight longitudinally extending structural elements interconnected by eight corner adapters in one piece. Each of the longitudinally extending structural elements has a predetermined length, which may be different depending on the size of the rectangular frame. Each of the elements includes a hollow extrusion formed from metal material. The metal extrusion defines an outer surface and an interior having open ends that have a predetermined shape. A hollow extrusion formed from plastic material defines an inner cross section having an inner surface, which is configured to receive metal extrusion thereon with the lower surface of the metal extrusion in confronting relationship with the inner surface of the metal extrusion. the extrusion of plastic. The corner adapters are formed from a non-corrosive structural material and each includes a central hub-shaped section. Three contiguous sides of the cube-shaped section cooperate to define an outer corner. Three other contiguous sides each have, extending therefrom, a tubular member having a cross section, which is configured to be received in a snap fit relationship within one of the open ends of one of the metal extrusions. The tubular elements each form an angle of 90 ° with respect to each of the two tubular elements. When the eight tubular elements of the predetermined lengths are assembled to the eight corner adapters to form the rectangular frame. All external surfaces of the frame are made of non-corrosive materials. BRIEF DESCRIPTION OF THE DRAWINGS The invention can be better understood and its objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings, in which: Figure 1 is a perspective view of a fan module having a structural frame constructed in accordance with the present invention; Figure 2 is an exploded perspective view of the fan module of Figure 1; Figure 3 is an enlarged detail view showing a corner adapter and three adjacent structural elements of the frame shown in Figure 2; Figure 4 is a view similar to Figure 3 having an intermediate structural element attached thereto;
Figure 5 is a view similar to Figure 4 taken from another angle thereof; Figures 6 and 7 are exploded views of the structure illustrated in Figures 4 and 5, respectively; Figure 8 is a perspective view of the intermediate structural element illustrated in Figures 4-7; Figure 9 is a sectional view taken along line 9-9 of Figure 4; Figure 10 is a sectional view taken along line 10-10 of Figure 4; Figure 11 is a top view of a corner adapter; Figure 12 is a side view of a corner adapter; and Figure 13 is a perspective view of a corner adapter. A fan module for use with an air handling unit having a rectangular structural frame according to the present invention is illustrated in Figures 1 and 2. The modular construction of the fan module is typical of that known in the prior art and includes a substantially rectangular frame supporting a pair of fans 12, a motor 14 and outer walls 15 for enclosing the interior components. The structural frame is defined by the use of eight one-piece corner adapters 16, each adapted to receive three of the free ends of eight horizontally extending elements 16 and four vertically to define a rectangular support frame thereby rigid solid. As mentioned, the frame is adapted to receive in a removable form and support outer wall panels 15, several of which are shown removed from the module 10 and others installed in Figure 2. Figure 3 specifically illustrates a corner adapter 16 the structure illustrated in Figure 2, having two horizontal structural elements 18h and a vertical structural element 18v extending from the corner adapter 16, as described above. It should be appreciated that the basic structure of the structural elements 18 are substantially identical regardless of whether they are oriented to the vertical or horizontal orientation. The only differences are in the length of the elements, as necessary for the size of the module being built. Each of the structural elements 18 includes an extrusion 26 of longitudinally extending aluminum interior, which is enclosed in an outer extrusion 28 made from a corrosion resistant material such as polyvinyl chloride (PVC), which also has properties insulators greater than that of aluminum. As best shown in Figure 10, the structural extrusion 26 includes a substantially square transverse section 30 defined by four walls 34. The upper left corner of the square cross section 30, as seen in Figure 5, is truncated by a section 36 that extends diagonally. The cross section of this defined mode extends the entire length of the extrusion 26 and thus defines openings having this cross section at the open ends of the extrusion. The diagonal section 36 has an inner wall 38 interconnecting ends of two of the four walls 34 · of the square section 30. As best seen in Figures 3 and 4, an outer wall 40 of the diagonal section 36 is separated from the inner wall 38 and includes a slot 42 extending longitudinally therein, which extends the entire length of the extrusion 26. As will be seen, the inner wall 38 and the outer wall 40 define a longitudinally extending channel 43 therebetween which is accessible through the slot 42 in the outer wall 40. Extending from the upper right end of the diagonal section 36 is a vertically extending support flange 44. Similarly, extending from the lower left end of the diagonal section 36 is a horizontally extending support flange 46. The outer PVC extrusion 28 completely surrounds the outer surface of the structural aluminum extrusion 26 described above. The outer channel 28 includes sections 48 and 50 vertical and horizontal double wall, respectively, which are interconnected with each other in a corner 52. Each of the double-walled sections has a single wall section 54 and 56 respectively, extending from the other end thereof, which is in proximity to the wall elements 34. short of cross section 30 square. Extending vertically upwards from the wall section 54 horizontally and horizontally from the vertical wall section 56 are the walls 58 and 60 of single thickness, respectively, which are in confronting relationship with one side of each flange 44 of vertical support and flange 46 of horizontal support. Formed at the outer ends of the walls 58 and 60 are the longitudinally extending U-shaped channel sections 62 and 64, respectively. Extending from the ends of the channels 62 and 64 are the horizontal and vertical walls 66 and 68 respectively. The walls 66 and 68 complete the protective closure of the vertical support flange 44 and the horizontal support flange 46. The sections
62 and 64 U-shaped are configured to receive stamps
63 of rubber elongated therein, as shown in Figures 2-7, which serve to provide an air tight seal for the walls 15 when installed in the frame. By interconnecting the ends of the walls 66 and 68 away from their U-shaped channel sections, there is a substantially flat wall 70 which is in confronting relationship with the outer wall 40 of the diagonal section 36. As will be appreciated from the description that follows, the interconnecting wall 70 lies on top and protects the outer wall 40 and substantially the entire length of the longitudinal slot 42 formed therein. Looking now at Figures 11, 12 and 13, the adapter
16 corner is shown in detail. Each corner adapter includes a section 72 in the form of a central hub. Three contiguous substantially flat sides 74 of the cube-shaped section 72 cooperate to define the corner 76 which, when the structural frame is assembled, defines the outer corners of the frame. Extending outwardly from the other three contiguous sides of the cube-shaped section are three tubular elements 78 extending longitudinally. Each of the tubular elements 78 has a greater length 80 thereof having a cross section substantially identical to the cross section defined by the four walls 34 and the diagonal inner wall 38 of the inner aluminum extrusion 26. The outer ends 82 of the tubular elements have substantially the same cross section, but taper towards the end thereof to facilitate the insertion of the tubular elements into the open ends of the aluminum extrusion 26. As best seen in Figure 13, the flat wall 84 of the largest section 80 of the tubular elements 78 is provided with a pair of raised sections 86 extending longitudinally therein. The wall 84 and the raised sections 86 couple the outer wall 40 of the diagonal section 36 of the extrusion 26 when a tubular element 78 presses therein to thereby secure the positive retention of the tubular element once inserted. As best seen in Figures 11 and 13, the section 72 in the form of a central hub defines a structure generally identified by the reference number 88 that surrounds the base of each of the tubular elements 78. The structure 88, which is configured to cooperate with the vertical and horizontal double wall sections 48 and 50 of the outer PVC extrusion and with the other wall sections 54 and 56 and 58, also formed by the PVC extrusion 28 . As a result, when a corner adapter 16 has three structural elements 18 attached thereto, as described above, the outer surfaces of the outer cover 28 cooperate with the three flat sides 74 of the corner adapters to define a smoothed transition. among them, as best seen in Figures 5 and 7.
Each of the flat sides 74 of the cube-shaped section 72 of the adapters has an L-shaped cut 90 in the inner corner thereof. Again, as best seen in Figures 5 and 7, these corner cuts cooperate with the walls 54 and 56 and 58 and 60 to define the channels in which the outer walls 15 are received when the walls are assembled to the assembled rectangular frame. . In one embodiment, the corner adapters are made from structural nylon. In the assembly of some modules where the module size requires structural elements longer than two meters in length, it is desirable to install intermediate structural elements 92, as illustrated in Figures 4-9. The intermediate structural elements 92 are defined by a longitudinally extending aluminum extrusion 94 having a rectangular cross section. Extrusion 94 is enclosed in PVC extrusion 96. The PVC extrusion includes a wall 98 of double exterior thickness and two sections 100 of double thickness that extend laterally and integrally formed therefor., which form the L-shaped channels 102 to receive the wall sections 15 therein. Prior to the assembly of the intermediate structural elements 92 to the frame, the upper and lower ends are cut so that they will cooperate with the upper and lower structural elements 18 to which they will be installed. The elements 92 are then positioned as illustrated in Figures 4-7, and a mounting bracket 104 having a lower flange 106 configured to engage the structural elements 18 and an upper flange 110, which extends along the rear side. of the structural element 92. The flanges are then appropriately secured to the structural element and the flange by threaded fasteners 112 extending from the inside of the rectangular frame through the PVC coating of the two elements (92 and 18) and into their underlying aluminum structural channels ( 94 and 96). Also, as will be seen in Figures 4-7, the threaded fasteners are also inserted through the ends 112 of the structural elements adjacent the adapters so that they will pass through the structural element and into the tubular elements 78 of the 16 corner adapters to ensure with this the positive union of its components with each other. It will be appreciated that none of the threaded components described above pass from the inside to the outside of the frame; rather they pass from the interior through a structural element and into a hollow channel, which is isolated to preserve the insulating properties of the frame, as described in the foregoing.