Abstract:
A refrigerator cabinet has an exterior cabinet shell and a plastic liner insert defining a fresh food compartment and a freezer compartment where foamed in place insulation extends between the exterior cabinet shell and the interior liner. The liner has a partition with upper and lower walls extending rearwardly of a front mullion wall and between sidewalls of the liner. The upper sidewall has a cut-out recess adapted to receive an evaporator tray housing that is seated on edges of the upper wall of the partition. The tray supports an evaporator coil, motor, and fan. The tray has a cover that forms, together with the upper wall of the partition, the floor of the freezer compartment. By locating the evaporator tray recessed in the partition, in the partition space between the two compartments can be filled with rigid foam that extends between the upper and lower food compartments and to the exterior shell of the cabinet.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an evaporator housing for a refrigerator where the evaporator housing is recessed within the floor of the upper food storage compartment from a single liner. The present invention more specifically relates to a novel evaporator housing for use in a top mount or bottom mount refrigerator cabinet where the evaporator housing is held in place by foamed in place insulation as a portion of the partition wall between freezer and fresh food compartments. 
     BACKGROUND OF THE INVENTION 
     Many present day household refrigerators include a freezer compartment maintained at a below-freezing temperature for the storage of frozen foods and a fresh food compartment maintained at an above-freezing temperature for storage of fresh foods. In many such refrigerators, an evaporator for providing cooling for both the frozen food compartment and the fresh food compartment is positioned outside both compartments and air is circulated over the evaporator and then through the compartments to cool the compartments. The evaporator itself is maintained at a temperature substantially below freezing. In order to maintain the greatly differing temperatures required in the two compartments, a substantially greater portion of the air flowing over the evaporator is directed to the frozen compartment. The air flow over the evaporator and into the freezer and fresh food compartments is controlled by baffles that regulate or reduce the air flow into the fresh food compartment. 
     In some refrigerators, the evaporator is mounted behind a false partition rear wall in the freezer compartment. The construction of the evaporator behind a rear wall of freezer compartment is shown in U.S. Pat. No. 4,944,157 issued Jul. 31, 1990 to Jenkins et al, U.S. Pat. No. 4,704,874 issued Nov. 10, 1987 to Thompson et al and U.S. Pat. No. 4,077,229 issued Mar. 7, 1978 to Gelbard et al. In each of these patents the refrigerator cabinet has a single cavity liner positioned within an exterior metal shell and a mullion partition divider mounted between the freezer compartment and the fresh compartment. The divider is secured relative to the liner side walls and rear wall. The evaporator is housed behind the false partition wall above the mullion partition. 
     In other refrigerators, the evaporator is mounted in the partition inserted into the single cavity plastic liner secured relative to the side walls and rear wall of the plastic liner. The construction of the evaporator in the partition divider dividing the single cavity of the refrigerator liner into a freezer compartment and a fresh food compartment is shown in U.S. Pat. No. 3,559,442 issued Aug. 17, 1991 to Robert S. Hanson, U.S. Pat. No. 3,766,976 issued Oct. 23, 1973 to Gelbard et al, U.S. Pat. No. 4,211,090 issued to Gelbard et al, U.S. Pat. No. 4,223,538 issued Sep. 23, 1980 to Braden et al, and U.S. Pat. No. 4,543,799 issued to Oct. 1, 1985 to Horvay et al. While each of these patents locates the evaporator in the mullion partition divider between the fresh food compartment and the freezer compartment, the mullion partition is a separate component of the refrigerator cabinet that is inserted into the liner cavity of the refrigerator and secured relative to the rear and side walls of the liner. The mullion partition has a structural strength limitation that is dependent upon the mechanical fastening of the mullion partition to the rear and side walls of the liner cavity. 
     There is a need for an evaporator housing to be located within the partition wall between the freezer and fresh food compartments and forms a portion of the partition wall of the refrigerator and where the partition wall is integrally formed with the remainder of the rear and side wall of the refrigerator liner. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a refrigerator cabinet having an exterior cabinet shell and a plastic liner insert defining a fresh food compartment and a freezer compartment where foamed in place insulation extends between the exterior cabinet shell and the interior liner. The partition separating the fresh food compartment and the freezer compartment is filled with rigid insulation to provide a rigid structure. The present invention has a recessed evaporator housing in the partition between the freezer compartment and the fresh food compartment. The evaporator housing is inserted through an opening in the floor of the freezer compartment. This construction of the evaporator housing has the advantage associated with locating the evaporator in the space between the two compartments permitting for good air flow over the evaporator coils and into the freezer and fresh food compartments while at the same time enjoying the advantage associated with the rigid foam in place construction of the partition and liner to the exterior shell of the cabinet. It should be understood that the present invention has equal application in both top and bottom mount styles of refrigerator cabinets. That is refrigerator cabinets where the freezer is located respectively either above or below the fresh food compartment. 
     In accordance with an aspect of the present invention, there is provided a refrigerator cabinet comprising an exterior cabinet shell having a top wall, a rear wall, a bottom wall, side walls and an open front side. The cabinet includes an interior liner adapted to fit within the exterior cabinet shell and spaced therefrom by insulation. The interior liner has integrally formed therewith a partition which together define lower and upper food storage compartments. The partition includes a front mullion wall and spaced apart upper and lower walls extending generally horizontally and rearwardly of the front mullion wall within the plastic interior liner. The upper generally horizontal wall of the partition has an opening therein. The evaporator tray housing is recessed within the opening of the upper wall of the partition. The evaporator tray housing has a floor portion for supporting an evaporator coil, a motor and a fan blade connected to said motor. Insulation within cabinet further extends into the partition between the upper wall, the evaporator tray housing, the lower wall and the front mullion wall. The cabinet further includes a cover for overlaying the tray housing. 
     The evaporator tray housing preferably has tray side walls upstanding from the floor portion of which at least two of the tray side walls each includes an out-turned rim adapted to overlay a portion of the upper wall of the partition. The floor portion of the evaporator tray housing is spaced from the lower wall of the partition and the tray side walls are spaced from the mullion wall and the side walls of the exterior cabinet shell. The evaporator tray housing preferably includes a front upstanding wall having a hooked shaped flange that overlaps the mullion front wall to provide support on an additional surface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the nature and objects of the present invention reference may be had by way of example to the accompanying diagrammatic drawings in which: 
     FIG. 1 is a perspective view of a top mount refrigerator; 
     FIG. 2 is an exploded view of the refrigerator cabinet showing the interior plastic liner, the mullion strap and the exterior cabinet shell; 
     FIG. 3 an exploded perspective view showing the details of the construction of the evaporator housing relative to the interior plastic liner of the refrigerator cabinet; 
     FIG. 4 is a front sectional view taken along lines  4 — 4  of FIG. 1 showing the evaporator tray housing located within the refrigerator cabinet; 
     FIGS. 5 and 6 are enlarged partial views of FIG. 4 for the evaporator tray housing; 
     FIG. 7 is a side sectional view showing the evaporator housing located in the refrigerator cabinet between the fresh food compartment and the freezer compartment; 
     FIG. 8 is a side sectional view similar to FIG. 7, where the section is taken through passage air inlets and the drain tube is located inside the fresh food compartment; and 
     FIG. 9 is a side sectional view similar to FIG. 8 showing the most preferred embodiment with the air inlet passage from the upper compartment extending through the mullion grill and the drain tube located within the partition wall. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to FIG. 1, there is shown a refrigerator  10  having an exterior cabinet shell  12 . The shell  12  is a thin sheet metal material. The refrigerator  10  includes an interior plastic liner  14 . Interior liner  14  defines upper and lower food compartments  16  and  18  separated by a partition  17 . The refrigerator cabinet  10  is a top mount refrigerator with the upper food compartment  16  is a freezer compartment and the lower food compartment  18  is a fresh food compartment. Access to the freezer compartment  16  and the fresh food compartment  18  is permitted at the front of the refrigerator  10  by opening doors  20 . Doors  20  have handles  22  which facilitate opening of the doors  20 . The bottom of the refrigerator  10  has a decorative kick plate  25 . Wile the preferred embodiment of the present invention is for a top mount refrigerator  10 , it should be understood that the invention alternatively may be used on a bottom mount refrigerator where the freezer compartment is located below the fresh food compartment. 
     FIG. 2 is an exploded illustrative view of the cabinet  26  components. During manufacture the interior liner  14  is inserted into open side  28  of the exterior cabinet shell  12 . This is represented by arrow  30 . A metal mullion strap  15  is shown positioned in the exterior cabinet shell  12  behind the liner  14 . Strap  15  extends across the open side  28  of the cabinet  26  inside partition  17 . 
     The exterior cabinet shell  12  has a shell edge flange  32  extending around the open side of the top wall  29 , bottom wall  31  and sidewalls  33  towards the opening of the open side  28 . The exterior cabinet shell  12  is made from sheet metal and includes a rear wall  35 . 
     The interior liner  14  is adapted to fit within the exterior cabinet shell  12 . The interior liner  14  includes an outwardly extending liner flange  34 . The liner  14  is a one-piece or uni-partite plastic material molded piece. A breaker strip (not shown) interconnects the liner flange  34  with the shell edge flange  32 . The liner  14  further includes openings  41  through which hinges (not shown) extend for the mounting of the refrigerator doors  20 . 
     The partition  17  separates the fresh food compartment  18  from the freezer compartment  16 . The partition  17  includes an upper partition wall  36 , a lower partition wall  38  and a front mullion wall  40 . The upper and lower partition walls  36  and  38  are spaced apart by the front mullion wall  40 . The upper and lower walls  36  and  38 , extend generally horizontally and rearwardly of the front mullion wall  40 . Preferably the walls  36  and  38  are angled slightly. The bottom partition wall is the upper wall of the lower food compartment  18  and the top partition wall  36  is the lower liner wall of the upper freezer compartment  16 . The upper partition wall  36  has an enlarged central opening  39 . Opening  39  is located rearwardly of the mullion wall  40  and extends back to the rear wall  44  of the upper food compartment  16  of the liner  14 . It is into opening  39  that the evaporator tray housing  46  of the present invention is seated in a recessed manner. 
     Referring now to FIGS. 3 through 9, the construction of the evaporator tray housing  46  for different preferred embodiments of the present invention with respect to the refrigerator cabinet is shown. In FIG. 3, a preferred construction for the evaporator tray housing  46  relative to the liner is shown. FIG. 4 is illustrative of the preferred tray housing  46  construction relative to the refrigerator liner  14  and the shell  12  of the refrigerator cabinet. FIG. 5 is an exploded view in more detail the relationship between the evaporator tray housing  46  and the interior liner  14  of the present invention. FIGS. 7 to  9  are cross-sectional views showing in detail the placement of the tray housing  46  relative to the interior liner  14 . 
     The evaporator tray housing  46  includes a tray cover  48 . The tray  46  has a floor portion  50  contoured to support evaporator coil  52 , motor  54  and fan blade  56  (see FIG.  8 ). The floor portion  50  is further provided with moisture runoff groove  58  and drain hole  60  connected to drain tubing  68  back through an opening in the lower partition wall  38  as shown in FIG.  8 . 
     In FIG. 9, the drain tube is located within partition  17  above the lower partition wall. The drain tubing  68  permits water to drain from the evaporator tray housing  46  when a defrost cycle for the refrigerator is initiated. During a defrost cycle, any frost build up on the evaporator coils is melted. 
     In accordance with the present invention the evaporator tray housing  46  is seated on the upper partition wall  36  recessed within the space of the partition  17 . After the insertion of the tray  46  into the freezer or upper freezer compartment  16 , a decorative grill  69  is secured on and over the mullion front wall  40 , the front portion of the top liner wall  36  and an edge portion of the tray  46 . A metallic plate or pan  72  is laid on the floor portion  50  of the tray housing  46 . The evaporator coil  52 , fan blade  56 , defrost heater  53  and motor  54  are assembled within the tray housing and suitable wiring extends through openings  74  located in a rear wall of the tray housing  46  (see FIG.  3 ). The cover  48  is placed over the tray housing  46  to close the evaporator tray  46  recessed within the partition  17 . A freezer floor plate  49  overlaps the cover  48 . 
     The metallic pan  72  is contoured to follow the shape of the floor portion  50  of the tray housing  46 . The pan  72  protects the plastic floor portion  50  by evenly dissipating heat generated from the evaporator coils during the defrost cycle and by preventing over-heating of plastic housing  46 . The plate  72  also drains water from underneath the evaporator coil to hole  60 . The pan  72  further includes a rear cut-out section  73  that allows heat transfer from the defrost heater  53  into the areas adjacent the fan blade  56 , the motor  54  and the drain area  58 . The defrost heater  53  is placed amongst coils  52  and is activated to accelerate the melting of frost during a defrost cycle. The heater  53  includes a metal shield cover  55  that deflects radiant heat away from the plastic cover  48 . Optionally, as shown in FIG. 8, an aluminum foil  57  with a drain heater attached is placed below the floor  50  of the tray housing  46  adjacent the fan blade  56  and motor  54 . The aluminum foil drain heater  57  is activated during a defrost cycle to prevent ice formation during and after the defrost cycle in the drain area  58  and the area of the fan blade  56 . 
     Referring to FIGS. 4 to  6 , the preferred constructions of the evaporator tray housing  46  within the partition  17  is described. The upper partition wall  36  has two elongated edges  70  that extend along the sides of the opening  39 . As best seen in FIG. 6, each of the edges  70  includes a depressed apron  172  extending downwardly from the upper wall  36  of the partition  17 . The depressed apron  172  further includes an in-turned flange  174  that extends from the apron  172  into the opening  39 . The in-turned flange  174  is a hook shape having an edge lip  176 . 
     The evaporator tray housing  46  includes at least two out-turned rib portions  178  extending outwardly from tray upstanding wall  80 . The out-turned ribs  178  are adapted to overlie a corresponding one of the in-turned flanges  174  of the upper wall  36  of the partition  17 . The floor portion  50  of the evaporator tray housing  46  is thus spaced from the bottom wall  38  of the partition  17  and the tray side walls  80  are spaced from the partition mullion wall  40  and the side walls  33  of the exterior cabinet shell  18 . Each of the out-turned rims  178  of the evaporator tray housing  46  has a downwardly depending rib  90  that rests on a corresponding in-turned flange  174  of the upper wall  36  of the partition  17 . The out-turned rims  178  of the evaporator tray housing  46  are shown with the downwardly extending rib  90  resting on the in-turned flange  74  between the apron  172  and the edge lip  176  of the edge  70  of the partition  17 . The out-turned rims  178  further include a sealing spacer gasket member  92  which is attached either to the rim  90  or to the apron  172 . This allows for a close fit of the tray  46  within the opening  39  of the partition  17  and seals to prevent insulation from leaking into the open area  16 . 
     Referring to FIG. 7, the evaporator tray housing front wall  80  has a hooked shape flange  96  that hooks over the forward wall or forward portion  97  of the upper wall  36  of partition provided immediately behind the mullion wall  40  to seat the tray  46  relative to the front of upper wall  36 . The evaporator tray  46  further includes an upstanding rear wall  80  which has a hook portion  98  into which the rear wall  44  of the liner is hooked into place. 
     The cover  48  of the evaporator tray housing  46  is press fitted into the tray housing  46  and over the evaporator coils  52 . The freezer floor plate  49  has an edge portion  112  with a hooked that is held recessed groove  110  forming a rear extension from the mullion grill  69 . The freezer floor plate  49  also slides into engagement with the back wall of the freezer compartment and is secured relative to upper partition wall  36  by fastening screws (not shown). 
     Referring to FIGS. 7 to  9 , side cross-sectional views of the tray housing  46 , tray cover  48  evaporator coils  52 , and the airflow through the housing  46  are shown. The primary difference between the embodiment of FIG.  8  and the preferred embodiment of FIG. 9 is that the drain tube  68  of FIG. 9 is located within the partition  17  whereas the drain tube  68  of FIG. 8 is located within the fresh food compartment  18 . 
     In FIGS. 7 to  9 , the airflow through housing  46  is depicted by arrows  200 . Motor  54  is activated to drive fan  56  which creates the airflow  200  through the evaporator tray housing  46 . Air  200  is cooled as it passes over the evaporator coils  52 . 
     The evaporator tray housing  46  has at least one lower inlet passage  120  and at least one lower outlet passage  122  extending through corresponding openings  124  and  126  in the lower wall  38  of the partition  17  to permit the air flow between the lower food compartment  18  and through the evaporator tray housing  46 . Additional supporting spacers  130  interconnect the lower air inlet passage and the lower air outlet passages with the corresponding lower partition wall  38 . Spacers  130  further support the evaporator tray housing  46  recessed within the partition  17  and prevent the escape of insulation from the partition  17  into the lower food compartment  18 . 
     For air circulation into the upper food compartment  16 , the lower wall  38  has a plurality of openings  140  (FIG. 9) and the grill  70  has openings  132  (FIG. 8) located adjacent the front mullion wall  40 . The refrigerator cabinet further includes a vent stack  150  extending upwardly from the evaporator tray housing  46  behind the cover  48  and over the interior liner rear wall  44 . The vent stack  150  includes a plurality of air outlet openings  152  that permit the air flow between the upper food compartment  16  and the evaporator tray housing  46  in through the cover inlet openings and out through the vent openings. 
     As best seen in FIGS. 4,  5 , and  7  to  9 , the upstanding sidewalls  80  of the tray  46  are surrounded by foam in place insulation  100 . The rigid insulation  100  is blown into the space between the liner  14  and the walls of the exterior cabinet shell  12 . The foam  100  during curing expands to fill voids between the freezer compartment  16  and the fresh food compartment  18  and thereby rigidly hold the evaporator tray housing  46  recessed within the partition  17 . The foam  100  extends from the sidewalls  33  of the exterior cabinet shell  12  around the liner  14  and across the partition  17  between the food compartments  16  and  18 . Further, the use of the spacers or grommets  130  at the air outlets, and the overlapping and sealing relationship between the out-turned rims  90  of the tray  46 , the in-turned flanges  174  of the freezer floor  36  and the sealing gasket member  92  prevent foam insulation from leaking into the evaporator tray housing  16 .