US3455119A - Plural compartment high humidity domestic refrigerator - Google Patents

Description

J. A. BRIGHT July 15, 1969 PLURAL COMPARTMENT HIGH HUMIDITY DOMESTIC REFRIGERATOR 4 Sheets-Sheet 1 Filed Feb. 16, 1968 Q faam] ATTORNEY J. A. BRIGHT July l5, 969

PLURAL COMPARTMENT HIGH HUMIDITY DOMESTIC REFRIGERATOR 4 Sheets-Sheet 2 .MJ ma@ m Z ,mf w W i. f w m, .m .w m..

ATTORNEY PLURAL COMPARTMENT HIGH HUMIDITY DOMESTIC REFRIGERATOR Filed Feb. 16, 1968 J. A. BRIGHT July l5, 1969 4 SheetsfSheet 5 ATTORNEY July 15, 1969 J. A. BRIGHT 3,455,119

PLURAL COMPARTMENT HIGH HUMIDITY DOMESTIC REFRIGERATOR Filed Feb. 16. 1968 4 sheets-sheet 4 .72 WIW- zw l ATTORNEY United States Patent O U.S. Cl. 62-180 4 Claims ABSTRACT OF THE DISCLOSURE In preferred form, a plural compartment domestic refrigerator including an insulated cabinet having a top freezer compartment, an intermediate air flow cooled compartment, and a bottom, sealed, high humidity compartment. A horizontal divider assembly at the bottom of the freezer compartment includes an evaporator over which air is circulated to cool the compartments. A duct system surrounds the liner of the humidity compartment and includes a counterilow heat exchanger for warming air from the evaporator prior to cooling the humidity compartment and for concurrently cooling return air from the duct system as it passes into said intermediate compartment.

This invention relates to plural compartment domestic refrigerators and more particularly to such refrigerators having a top freezer compartment and a bottom food storage compartment having a high humidity sealed chamber of the type defined by liner walls that are cooled by a surrounding dry air ow duct system included as part of a frost free air ow cooling system for the freezer compartment.

Certain domestic refrigerators include an insulated cabinet structure having a top freezer compartment and a bottom food storage compartment both of which are cooled by air flow across a refrigerant evaporator located in a horizontal insulated partition between the compartments. Both the freezer compartment and bottom food storage compartment have a forced draft flow of dry air passing therethrough that dehydrates exposed foodstuffs. Accordingly, an object of the present invention is to prevent dehydration of foodstuffs in plural compartment domestic refrigerators of the type having a top freezer compartment and a bottom food storage compartment cooled by a forced draft flow of dry air by dividing the food storage compartment into a sealed humiditied chamber and an intermediate compartment located between the humidified chamber and the top freezer and by directing a part of the air flow into a fluid circulating system having a counterow heat exchange concurrently warming the air flow prior to passage thereof into surrounding relationship with the outside of a liner surrounding the humidified chamber and cooling air flow being returned from said liner and diverting part of the recooled return air ow into and through the intermediately located compartment or space for convectively cooling the contents thereof.

A further object is to prevent dehydration of food stored in a plural compartment domestic refrigerator of the type having a top freezer and a bottom food storage space separated one from the other by a horizontal thermally insulated partition, and wherein the freezer is cooled by air ow across a refrigerant evaporator disposed in a cooling plenum within the freezer by the provision of means for sealing part of the bottom food storage space to form a humidiiied space separated from dry, cold air ow through the freezer, said means including a liner having a cooling duct system therearound that ICC receives air from the cooling plenum under the control of thermally responsive valve means sensing the temperature of the humidilied space, and by the further provision of a manually operated damper assembly that diverts part of the air flow from the liner cooling duct system into a compartment located intermediate the freezer compartment and humidied space for cooling it by convection, and wherein a counterflow heat exchanger -is located between the thermally responsive valve means and the duct system and the manually operated damper assembly for concurrently warming air ilow from the cooling plenum prior to passage thereof into the liner cooling duct system and to cool air flow from the duct system prior to passage thereof into the intermediate compartment thereby to improve etiiciency of operation of the refrigerator.

Still another object of the present invention is to reduce food dehydration in a frost free domestic refrigerator of the type including an insulated cabinet having a top freezer compartment and a bottom food storage compartment separated from one another by a thermally insulated horizontal partition and wherein the freezer is cooled by forcing air through a cooling plenum containing a refrigerant evaporator by the provision of; means in the food storage compartment precluding dry air ow therethrough including a humidied compartment liner having a bottom, sidewalls and a rear wall to maintain high humidity level therein; a iluid circuit for diverting air from the cooling plenum and away from the freezer compartment downwardly through the insulated cabinet, rearwardly of the humidited compartment liner under the control of valve means for proportioning airflow between the freezer and the uid circuit. The circuit includes a duct system overlying the rear, sidewalls, and bottom of the liner and formed to distribute dry cooling air from the plenum against the liner to cool it and the contents of the humidied compartment without dehydration; and means for completing the fluid circuit between the liner cooling duct system and the cooling plenum of the refrigerator including a counterflow heat exchanger for warming air from the cooling plenum prior to passage thereof through the liner cooling duct system and for cooling air ow from the liner cooling duct system prior to return thereof into the cooling plenum and manually operable control means diverting a part of the counterflow heat exchanger cool air through a third compartment for convectively cooling the contents therein.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a view in perspective of a plural compartment domestic frost free refrigerator including the present invention;

FIGURE 2 is an enlarged View in horizontal section taken along the line 2-2 of FIGURE 1 looking in the direction of the arrows;

FIGURE 3 is an enlarged vertical sectional view taken along the line 3 3 of FIGURE 1 looking in the direction of the arrows;

FIGURE 4 is an enlarged fragmentary vertical sectional view taken along the line 4-4 of FIGURE 1 looking in the direction of the arrows;

FIGURE 5 is an enlarged fragmentary vertical sectional view taken along the line 5 5 of FIGURE 1;

FIGURE 6 is a fragmentary view in perspective of a freezing compartment and cooling plenum in the refrigerator of the present invention;

FIGURE 7 is an exploded view in perspective of part of a duct system for distributing air in the refrigerator of the present invention including components of a counterow heat exchanger therein;

FIGURE 8 is an enlarged fragmentary horizontal sectional view taken along the line 8 8 of FIGURE l looking the direction of the arrows;

FIGURE 9 is an enlarged fragmentary horizontal sectional view taken along the line 9-9 of FIGURES 3 looking the direction of the arrows;

FIGURE 10 is an enlarged vertical sectional View taken along line 10-10 in FIGURE 2 looking in the direction of the arrows;

FIGURE ll is an enlarged fragmentary front elevational view looking in the direction of arrows 11-11 of FIGURE 8, and

FIGURE l2 is a wiring diagram of a control system for association with the present invention,

Referring now to the drawings, in FIGURE l there is illustrated an insulated refrigerator cabinet 14 having an outer shell formed in part by a rear wall 15 joining spaced apart side -walls 16 and 17, a top 19 and a bottom 20. The insulated cabinet 14 further includes, as seen in FIGURE 3, a support base 22 in part defined by a depending skirt 23 thereon which encloses a machinery compartment 24 having an access opening 26- thereto formed in the front of the support base 22 closed by an apron or kick plate 28. Within the outer shell of the cabinet 14 is located an inner liner 30 having a rear wall 32, spaced apart side walls 34, 36, a bottom 38, and a top 39. Insulation 41 fills the space between liner 30 and the outer shell of cabinet 14.

A radially outwardly directed connecting flange 40 on the liner 30 is formed substantially continuously completely around the front edge of the side walls, bottom and top thereof for connection to the front edge of the outer refrigerator shell by means including spaced apart side breaker strips 42, 43, a top breaker strip 44 and a bottom breaker strip 45.

Within the liner is located a horizontally disposed thermally insulated partition assembly 46 which divides the inner liner 30 into a below freezing space or freezer compartment 48 at the top of the cabinet and a bottom located above freezing space 49 for general food storage. The above freezing space in turn is separated by a high stress glass divider plate 50 into a bottom high humidity zone or chamber 52 and a flowing cold zone that is formed in a compartment 54 located intermediate the high humidity chamber 52 and the freezer compartment 48.

The freezer compartment 48 is closed by a top door closure 56 that is representatively illustrated as being hinged on the cabinet 14 and movable from the open position shown in FIGURE 1 to a closed position where a continuously formed magnetic sealing gasket 58 on the inside face of the door 56 engages the cabinet 14 around a front cabinet opening 59 to the freezer compartment.

The refrigerator further includes a bottom door 60 having a magnetic sealing strip or gasket 62 on the inside surface thereof forming continuously around the outer perimeter thereof that is engageable with the cabinet 14 to close lower front cabinet opening 63 into the compartment 49. On the door 60 is located a shelf 64 having a shape that fits into a` notched front 66 in the divider plate 50 between zones 52 and 54. A fiexible resilient gasket member 68 on shelf 64 sealingly engages the notched front of the shelf 50 when the door is `closed to seal between the high humidity chamber 52 and the flowing cold intermediate compartment 54.

In one working embodiment of the insulated refrigerator cabinet described above, the outer shell of cabinet 14 is steel with an acrylic enamel finish; the inner liner 30 is a full length one-piece enameled steel unit; the breaker strips are suitable plastic moldings and the insulation 41 between the cabinet 14 and the liner 30 is foamed in place urethane foam. The cabinet components cited are merely illustrative, it being understood that the details of construction of the cabinet shell, the liner and the insulation therebetween are merely selected to produce a predetermined thermal insulating barrier between the interior of the cabinet 14 and the surrounding ambient conditions to maintain, with a given refrigerant system, a desired operating temperature in the various compartments of the refrigerator.

Referring now more particularly to the thermally insulated partition assembly 46, as best seen in FIGURE 3, it includes a -at horizontally disposed plate 70 extending across the lower reaches of the freezer compartment 48 to form a false bottom thereacross. Below the plate 70 is located a slab 72 of thermal insulating material such as molded expanded polystryrene that defines the top of a cooling plenum or evaporator compartment 74. A slab of thermal insulating material 76 forms the bottom of plenum 74 and is supported by a retaining plate 78 which in turn is supported by suitable fastening means (not shown) on the liner 30.

Within the evaporator compartment 74 is located an evaporator assembly 80 which is best illustrated in FIG- URE 6 as including a continuously looped and sinuously formed coil portion 82 having a first plurality of inlet fins 84 connected thereto in heat transfer relationship therewith spaced apart a substantial distance through a part of their length to define a substantially open air flow passageway through the evaporator assembly 80 at the front thereof. Behind the openings between fins S4 are located a second pluarlity of fins 86 joined to the tube 82 and located between the fins 84 to increase the heat transfer surface associated with the tube 82.

The cooling plenum 74 includes a first plurality of inlet openings across a front face portion 88 thereof as defined by louvered openings 90 therein and further includes a second inlet opening constituting a plurality of spaced apart ports 92 located andlextending through the front edges of the insulating slab 76 and retaining plate 78 to intercommunicate the flowing cold zone or intermediate compartment 54 with the cooling plenum 74. Additionally, and as is best seen in FIGURE 5, the cooling plenum 74 has a third inlet thereto defined by an opening 94 in an upwardly directed air flue 95 discharging into a space 96 between the underside of a drain pan 98 and the bottom of the cooling plenum 74 as defined by the insulation 76 and retaining plate 78. Space 96 communicates around the front edge of the drain pan 98 rearwardly of the louvered front face 88 and into the inlet spaces formed between each of the fins 84 of the assembly 80. As is best seen in FIGURE 3, the drain pan 98 is inclined downwardly toward the rear of the compartment 76 toward an outlet fitting 100 which is connected by a drain conduit 102 into a condensation collecting pan 104 located within the ma chinery compartment 24.

In the illustrated embodiment of the invention the evaporator assembly 80 is operatively associated with a compressed refrigerant system including a hermetically sealed motor compressor unit 105 that discharges refrigerant into and through a refrigerant condenser 106 that in turn is connected by a conduit 108 through a capillary tube (not shown) to the inlet end of the coil 82. The outlet of the coil 82 communicates through an accumulator (not shown) and a return refrigerant line 110 to the suction side of the compressor in the unit 105.

For purposes of the present invention it is only necessary to point out that the hermetically sealed motor compressor unit 105, when energized, across a suitable power source is operative to draw refrigerant from the accumulator downstream of the evaporator coil 82 and discharge it for serial fluid ow through the condensor 106, inlet line 108, the capillary tube serving as a means for expanding the refrigerant, and thence into the coil 82 where the expanded refrigerant gas absorbs heat from within the cooling plenum 74 for subsequent dissipation at the condensor 106 by air flow thereacross. If desired a condensor fan 112 can be included for this purpose. Y

In the illustrated refrigerator a deliector plate 114 is located at the rear wall of the freezer compartment 48 to cooperate with the insulating slab 76, drain pan 98 and a fan housing 115 to define an outlet opening or passageway 116 communicating the rear of the plenum 74 with an inlet opening 118 in the fan housing 115. A multivaned impeller 120 driven by an electric motor 122 is located within a plurality of diffuser vanes 124 extending circumferentially about and radially outwardly of the multivaned fan impeller 120 as best seen in FIGURE 6. The diffuser vanes 124 convert velocity head to pressure head and direct air discharged from the impeller 120 in part through a vertically directed passageway 126 formed by a vertical reach of housing 115 that communicates with the upper part of the freezer compartment 48. The outlet from the passageway 126 is covered by an inverted U-shaped outlet deflector member 128 to divert part of the air fiow through the passageway 126 downwardly and across the rear part of the compartment 48 and part through the top of the compartment 48. The combined flow through the compartment 48 is returned to the cooling plenum 76 through the first inlet constituted by the louvered openings 90. The air fiow pattern is generally shown by the arrows in FIG- URE 3 and constitutes a first fluid flow circuit in the refrigerator.

Additionally the impeller 120 discharges through the diffuser vanes 124 into a downwardly directed outlet duct 130 which communicates through a tubular fitting 132 defining a ow passageway in a thermally responsive damper valve control assembly 133. In the illustrated arrangement, the thermally responsive control assembly 133 includes a butterfly or damper valve 134 extending across the interior of the fitting 132. Valve 134 is pivoted by an actuator arm 136 connected to an operating bellows 138 connected to an elongated tube 140. The tube 140 extends behind the rear wall 32 of the liner 30l in a recess formed by a ribbed segment 142 of the liner 30 along the rear part of the high humidity chamber 52 (see FIGURE 2) whereby a thermally expansible iiuid within the tube 140 and bellows actuator 138 Will selectively expand and contract in response to the temperature changes within the compartment 52. This causes the operating bellows 138 through the actuator arm 136 to move the valve 134 to a more open or closed relationship with respect to the fitting 132. Thus, a greater or lesser amount of air discharged from the fan or impeller 120 is passed through the outlet duct 130 rather than directly through the freezer compartment 48 via the vertically directed passageway 126 defined by the fan housing 115.

From the tubular fitting 132, under the control of the damper valve assembly 134, air flows through an inlet duct 144 into an air distribution system 146 interposed between the inlet duct 144 and the previously described vertically directed return fiue 95 in which is located the opening 94 defining the third inlet into the cooling plenum 76.

As is best seen in FIGURE 7 the air distribution system 146 is illustrated as including a first multi-armed duct member 148 which, generally, is located rearwardly of the rear wall 32 of the liner 30 between it and a second multiarmed duct member 150. Between the duct members 148, 150 is located a heat transfer plate 152 cooperating with parts of each of the multi-armed duct members 148, 150 to define a counter-How heat exchanger assembly designated by the reference numeral 154 in FIGURE 3 of the drawings.

A trunk portion 155 of the duct member 150 cooperates with the heat exchanger plate 152 to define an inlet passageway 156 in system 146 communicating with the duct 144 for receiving air from the fan impeller 120 through the thermally responsive control assembly 133. The inlet passageway 156 is located rearwardly of the rear wall of the liner 30 and extends from the inlet duct 144 to the bottom of the liner 30 rearwardly thereof. Adjacent the lower reach of the trunk 155 of the duct member 150 a flow splitting divider 158 is formed that separates the trunk 155 into lower branches 160, 162, each of which has a flanged edge 163 thereon that is connected to a flanged edge 165 on lower branches 164, 166 on member 148 that cover the spaces on either side of the divider 158 thereby to define a first bottom outlet passageway 168 on one side of the air distribution system 146 and a like bottom outlet passageway 170 on the opposite side thereof. Located on the branches 160, 162 of the duct member 150 are guide vanes 171. Also included herein are secondary ow diverter ribs 172, 174 that intercept downward air flow from the inlet passageway 156 into the outlet passageways 168, 170 to divert it into a lower part of a liner cooling duct system 176. The system 176 is generally shown in FIGURE 1 as overlying the bottom, side walls, and rear wall of the liner 30 at the high-humidity section to cool the liner walls in this vicinity thereby to reduce the temperature within the chamber 52 by conductive heat transfer across the liner walls rather than cooling by forced-draft air fiow through the interior of the chamber 52.

More particularly, the liner cooling duct system 176 includes a bottom member 178 cooperating with a cover member 180 to define a pair of spaced-apart, U-shaped flow passageways 182, 184 underlying liner bottom 38. The passageways 182, 184 communicate with passageways 168, 170 and with lower side ducts 186, 188 of the duct cooling system 176 as best seen in FIGURE 2.

The duct 186 is located in overlying juxtaposed relationship with one side of the liner 30, and it is covered by a member 190 located in spaced relationship therewith. The duct member 188 is located in like relationship with the opposite side of the liner 30 and is covered by a member 192 located in spaced relationship therewith.

As seen in FIGURES 1 and 2 looking toward the front of the' refrigerator, the duct member 186 and cover 190 define a right lower passageway 194 extending from the rear corner of the liner substantially to the front edge thereof. Likewise, on the opposite side of the box, as seen in FIGURE 2, the duct 188 and cover 192 cooperate to define a left lower passageway 196 also extending from the rear corner of the liner 30 substantially Iits front edge. As seen in FIGURE 10 a thin layer of thermal insulation such as a fiber glass blanket 197 is sandwiched between each of the side ducts 188, 190 and side walls of liner 30.

A reversely curved diverter 198 separates passageway 194 from an upwardly located right side passageway 200 extending from the front of the liner 30 to the rear corner thereof and likewise, on the opposite side of the box, a reversely curved diverter 202 separates the lower left passageway 196 from an uper left flow passageway 204 across the side walls of the liner.

Referring now to FIGURE 7, it will be seen that the duct member 150 includes upwardly located Wings 206, 208 located rearwardly of the rear wall 32 in spaced covering relationship to like wings 210, 212 on the duct member 148. Edges 209, 211 on the wings of members 148, 150 are joined at these points to define outlet passageways 214, 216 from the upper passageways 200, 204 respectively of the liner cooling duct system 176.

TheI wings 210, 212 are joined by a transition piece 218 which, as seen in FIGURE 3, is sealed against the bottom edge of the heat exchanger plate 152 and is located in spaced relationship therewith to define the beginning of an upwardly directed flow passageway 220 which, at the top of the heat exchanger plate 152, communicates with an inclined, upwardly directed return passageway 222 formed by an upper side extension 224 on the duct member 148 and a similarly shaped upwardly directed extension 226 on member 150 serving as a cover for extension 224. The extensions 226, 224 merge with the previously mentioned return flue 95 having inlet opening 94 to plenum 74.

The extension 224 includes an opening 228 thereon which is in communication with a tubular extension 230 on the plate 152 which in turn communicates with a recessed groove 232 in the extension 226. These parts dene a path between the inlet passageway 146 and a liner port 233 through which cold air from the evaporator is directed into heat transfer relationship with a meat tender box 234 Within the flowing cold zone defined by the intermediate compartment 54.

The extension 224 also has an arcuate opening 235 therein which is aligned with a like arcuate opening 236 in the rear liner wall 32 at a point above the divider plate 50 as best seen in FIGURE 11. This defines an inlet opening for air flow into the owing cold zone of compartment 54. Flow through openings 235, 236 is under the control of a manually adjustable damper assembly 237 including a rotatable control knob 238 located in front of a control cover 239 extending across the width of the rear liner wall adjacent thereto at a point immediately below partition assembly 46.

An actuator arm 240 on knob 238 has a damper plate 241 attached thereto and a plurality of tabs 242 thereon are interlocked with the liner to hold the damper plate 241 in overlying relationship with openings 235, 236.

In addition to covering the operative parts of the manually-operated control assembly 237, the cover 239 further encloses a thermostatic controller 243 having a rotatable operating knob 244 movable with respect to suitable indicia to establish temperature control within the freezer compartment 48. The thermostatic controller 243 is of a conventional form including a switch opened and closed by a bellows actuator. In the illustrated arrangement an elongated tube 246 filled with thermally expansible fluid communicates with the bellows actuator and is located at the rear of the freezer compartment liner to sense its temperature.

Referring now to the wiring diagram of FIGURE 12, a motor energization circuit for the motor compressor unit 105 is shown running from wire L1 through conductor 248 and a movable electrically-conductive switch blade 250 of a defrost controller 252. A contact 254 engages blade 250 and is electrically connected by conductor 256 through a switch 258 operated by the thermostatic controller 243, in response to temperature conditions within the freezer compartment 48. The motor energization circuit continues through a conductor 260 connected to one side of a start relay 262 having an overload switch 264, a start coil 266 and start contacts 268, 270 connected during initial motor energization to one side of a motor start capacitor 272. The opposite side of capacitor 272 is connected to the phase winding 274 of an induction type AC electrical drive motor 275 of the unit 105. The phase winding 274 is electrically connected by a conductor 278 through an overload protector 280 to wire N. From coil 266 a conductor 282 is connected to one side of the main motor winding 276 which has its opposite side electrically-connected by conductor 278 to wire N.

Additionally, the wiring diagram includes a motor energization circuit for the freezer fan motor 122. This is identical to the motor energization circuit to the switch 258 of the thermostatic controller 243. From this point a conductor 284 connects to one side of the freezer fan motor 122 which has the opposite side thereof electrically connected by conductor 286 back to wire N.

The diagram further includes means for energizing a fan motor to drive a fan in the high humidity compartment to be discussed. This circuit runs from Wire L1 through conductor 248, thence through a conductor 288 electrically connected to one side of a solid-state speed controller 290 of a type set forth in copending United States application Ser. No. 607,693, filed Ian. 6, 1967 to James Canter. The opposite side of the controller is connected by a conductor 291 to a humidiied compartment fan motor 292 thence through a conductor 294 to wire N.

A low voltage liner heater 295 is connected across switch 258. to serve aslan-off-cyclc heat source between inlet passageway 156 and liner rear wall: 32 for reasons to be discussed. The heater 295 is strung across rear wall 32 as best seen in FIGURE'l'. i

A condenser fan motor-2971's connected betweenwires L1 and N to drive fan-.112 during; operation of motor Compressor unit 105. v "i As shown in FIGURE l2, the wiring diag'ramjis 'conditioned for refrigeration and concurrent energization of condensor fan motor, the compressor v-rnotor,'the` freezer fan motor and the foodcompartmenty fanmotorL-During a defrost cycle the circuit, underrfhe'fcontrol ofthel defrost controller 252, periodically will have the blade 250 positioned out of engagement withecontact 2547thereby to open the freezer fanmotor -and compressor "motor circuits, the blade then moves into Velectrical engagement with a back contact 298.

From the contact 298 a defrost heater energization circuit passes through a conductor 299, a thermal overload or limit switch 300, a conductor 301 connected to one side of an electrical resistance element 302 that is wound through the evaporator assembly 82 and insulated therefrom by suitable electrical insulation means to serve as a defrost heater. The opposite side of the element 302 is connected by a conductor 304 to Wire N.

The contemplated mode of operation for defrost operation is to establish a predetermined time period of energization of the resistance element 302 during a twenty-four hour period or the like with the duration of the timed period of resistance element energization being suflicient to assure complete melting of frost buildup from the fins and coil surfaces of the evaporator assembly 80.

As will be noted, during the defrost period of operation wherein the resistance element 302 is energized, the compressor motor circuit, the condenser fan motor circuit, and the freezer -fan motor circuit all will be deenergized. The fan motor energization circuit for circulating air in chamber 52, however, remains energized through both the refrigeration and defrost periods of operation as established by the controller 252 thereby to prevent any undesirable buildup of moisture condensationon the underside of shelves such as the divider plate 50.

Before discussing the detailed functional and operational aspects of the preferred embodiment described above, the following electrical characteristics of the system are noted:

Humiditied chamber fan motor 292 94 ohms. Defrost heater 302 21.4 ohms (640 watts). Freezer fan motor 122 47 ohms. Condenser fan motor 297 68 ohms Compressor motor phase winding 274 9.4-1l.0 ohms. Main winding 276 1.8 ohms. Capacitor 272 130 microfarads. Liner heater 295 880 Ohms (15 watts). Thermostatie controller 243 setting 6 F./+7 F. Thermostatic damper control 133 setting (fully closedfully open) +26 FJH-32 F- Fan impeller 50 s.c.f.m. Fan impeller 306 5-10 s.c.f.m.

A circuit having operative components with the ratings listed above in the plural compartment refrigerator assembly of the present invention are used to cool a food storage compartment 49 having a Volume (including door shelf space, not shown) of 16.3 cubic feet. The freezer compartment 48 has a volume of 4.35 cubic feet including door space.

The refrigeration cycle of operation thereof maintains a temperature within the freezer compartment 48 of approximately 0 F. to +10 F.; a temperature Within the fiowing cold zone defined by compartment 54 in the order of 32 F. to 38 F.; a temperature within the humidified chamber 52 of approximately 32 to 38 F.; and a liner temperature at the bottom, rear and sides of the chamber 52 of substantially 32 F.

The detailed operation of the above-described irnproved plural compartment refrigerator during the refrigeration cycle is as follows:

When the door 60 is closed, the energization circuit for the freezer fan motor 122 is completed between wires L1 and N. This will cause the freezer compartment 52 to be cooled by the fan impeller 120 drawing air from the outlet passageway 116 for discharge through the vertically directed passageway 126, thence to be evenly distributed by the defiector member 128 through the compartment 48 for return through louvered openings 90 into the evaporator assembly `80, thence across fins 84, 86 on the coil 82 where moisture from the compartment 48 is deposited as a frost buildup on the fins. The air ow is cooled to a temperature which in the outlet passageway is in the order of 4 F. The advantage of the wide spacing between the fins -84 through the inlet part of the evaporator assembly 80 becomes apparent when the matter of frost buildup on the evaporator is considered. The moisture from compartment 48 will initially deposit on the front edges of the fins 84 and the wide spacing will be preselected to assure an adequate air ow passageway during the complete refrigeration cycle of operation and prior to the defrost cycle as established by controller 252.

The temperature within the freezer compartment 48 is established 'by the setting of the knob 244 of the controller 243. The elongated sensing tube 246 of the controller, by being in engagement with the rear liner wall of the compartment 48 will, at a temperature of 6 F., cause a bellows operator to open the switch 258 thereby to deenergize fan motor 122, the condenser fan motor 297 and the compressor motor 275 and energize the liner heater 295. Liner heater 295 prevents ice accumulation or formation on the liner Walls in the high humidity chamber 52 under high temperature ambient conditions.

Refrigerant iiow through the coil 82 of the evaporator assembly 80 is controlled to maintain a temperature within the cooling plenum 74 which, with a given period of rfreezer fan operation, will maintain temperatures within the freezer compartment 48 within the limits set forth above within a given range of ambient temperature conditions, for example, from F. to 110 F. The controller 243, as noted above, will close when the liner wall reaches a temperature of +7 F.

The damper valve control assembly 133 through the sensing tube 140 in response to the temperature within the sealed humidified chamber 52 controls air flow through the alternate or second outlet duct 130 and controller fitting 132. If the liner becomes too warm the fiow is increased and there is a reduced fiow if the compartment and liner become too cold. The control range of the damper is sufiicient to maintain the temperature within the moist cold zone defined by chamber 52 within the limits set forth above.

To accomplish even cooling of the liner walls at chamber 52 and to maintain them at a temperature fluctuating on either side of 32 F., an important aspect of the present invention is the configuration of the air distribution system 146 that is disclosed in FIGURE 7 in an exploded manner. Also of importance is the inclusion of the counterfiow heat exchanger device 154 therein between the air flow controller or damper valve 134 and the outside surface of the liner 30 about the chamber 52 and the air iiow passageways through the fiowing cold Zone or compartment 54.

To understand the importance of this configuration, it should be noted that the air ow through the duct 130 and controlled by the damper valve 134 has a subfreezing temperature in the order of 4 F. and has been dried by frost sublimination on assembly 80. The subfreezing temperature is necessary to maintain the operating range within the freezer compartment 48 mentioned above.

When subfreezing air flow of this type is directly impinged against the outer surface of a liner surrounding a high humidity compartment, one in which moisture can and often does condense on the walls of the liner, the liner will be vcooled to a temperature substantially below freezing and thereby serves as a surface upon which the free moisture in the compartment will be deposited as frost. Such operation defeats the purpose and intent of frostfree refrigeration operation.

Accordingly, the subfreezing air Iin the present invention, as best seen in FIGURE 3, will iiow from the damper valve 134 through the inlet duct 144 into the cold side inlet passageway 156 between trunk portion 155 of duct member and the exchanger plate 152. This passageway is maintained in a spatial relationship with respect to the rear liner wall 32 of the compartment 52 to, in part, prevent the frost buildup condition mentioned above. Now, as the air fiow through passageway 156 progresses downwardly behind the rear wall of the liner 30, it will receive heat through the exchanger plate 152 of the counterflow heat exchanger assembly 154 to be further Warmed to further assure that the subfreezing air supply will not undesirably reduce the temperature of the liner walls of the chamber 52 below freezing.

In the working embodiment of the invention described above, the temperature of the air fiow leaving the exchanger 154 at the bottom edge of the heat transfer plate 152 is at a temperature of 10.5 F. This air passes through the fiow splitter or divider 158 into the bottom outlet passageways 168, on either side thereof. The air flow through the outlet passageways 168, 170 is picked up, respectively, by the flow diverter ribs 174, 172 to scoop part of the 10.5 F. air flow through each of the outlets into the U-shaped flow passageways 182, 184 immediately underlying the bottom 38 of the liner forming the sealed high humidity chamber 52. The amount of air passed under the bottom through the U-shaped passageways 182, 184 is returned back into the outlet passageways 168, 170 in a reverse fiow fashion shown by the arrows in the perspective view of FIGURE 1. This return iiow along with the undiverted part of the flow through the outlet passageways 168, 170 then passes around the rear corners of the liner 30 into the lower passageways 194, 196 formed in the side ducts 186, 188, respectively, of the liner cooling duct system 176 around the compartment 52. The air ow is divided substantially evenly and, at the point where it enters the passageways 194, 196, it is at a temperature of approximately 20 F. in the working embodiment.

It is important to note that the amount of air diverted through the U-shaped bottom ducts 182, 184 is of a quantity and temperature to preclude frost build-up on the bottom 38 within chamber 52.

The 20 F. air in the lower side passageways 194, 196 is diverted by the reverse bend bafiies 198, 202 into upper passageways 200, 204, respectively, of the side ducts 186, 188 and, as best seen in FIGURE 2, the divided air liow thereafter passes around the corners of the liner into the outlet passageways 214, 216 between the side wings on duct members 148, 150. At this point in the working embodiment, the temperature of the air hasbeen substantially increased by heat exchange from the humidified chamber 52. As previously indicated, the heat exchange through the liner walls is in part manifested by maintaining the walls of the liner 30` at and around the chamber 52 substantially at or near 32 F. The wall temperatures will at times fall above and below this figure but, during steady state equilibrium conditions, this design criteria s generally met by the present invention.

Another manifestation of the above-described heat eX- change across the liner walls into the humidified chamber 1l 52 is that none of the cold, dry air stream passing from the cooling plenum downwardly of the refrigerator cabinet is passed directly through the chamber 52. Accordingly, the problem of high velocity, forced draft dehydration of foodstuffs of the type normally found in frostproof refrigerators, and more detailedly mentioned in the preliminary introductory remarks of this specification, are not present within chamber 52.

Still another manifestation of the particular heat exchange action between the air distribution system 146, the liner cooling duct system 176 and the chamber 52 is the temperature of the air ow through the side wing outlet passageways 214, 216. The -heat exchange through the liner walls increases the temperature of the air stream near to the freezing mark in the working embodiment to approximately 29 F. An air stream having this temperature is liimted as to performing any meaningful further cooling within the refrigerator.

Thus, a further important aspect of the present invention is found in the manner in which the air stream is directed from passageways 214, 216 through the counterflow heat exchanger 154. As was previously indicated, the subfreezing air passing into the cold side or passageway 156 of the exchanger 154 receives heat through the transfer plate 152. This heat is that present in the flow from the duct system passageways 214, 216. This air flow merges at passageway 220 between the duct members 148, 150 to pass vertically upwardly across the side of the heat transfer plate 152 facing the duct member 148. The passageway 220 constitutes the warm side of the exchanger 154 and the air flow therethrough constitutes a thermal insulating barrier to prevent the subfreezing air source constituted by the forced draft through duct 130 and valve 134 from producing a frost buildup problem on the liner of the humidified compartment 52.

As the upward warm air flow from passageway 220 passes in reverse or counterow relationship to the downward subfreezing air ow through the passageway 156 it is cooled to a point where, as it passes into the vertically inclined return passageway 222, it will be capable of performing an additional cooling function in the refrigerating apparatus. More particularly, in the working embodiment, following flow through the warm side of exchanger 154, the air stream is reduced in temperature from 29 F. to 14.5 F.

The recooled air ow for the most part is directed upwardly through the return flue 95, thence through the opening 94 therefrom, into the return space 96. It t-hen flows around the front end of the drain pan 98, into the evaporator assembly 80 from whence the fan impeller 120 will draw the air along with that from the freezer compartment for redistribution. The recooled air has a very low relative humidity since it is separated from the interior of the compartment 52 by the closed duct system.

A smaller amount of the air flow in the passageway 222 is under the control of the manually adjustable damper assembly 237 and passes through aligned, arcuate openings 235, 236 rearwardly of the control cover 239, thence through a grilled in the front thereof, directly into the flowing cold intermediate compartment 54 where it circulates at a very low velocity and is eventually returned through the top front ports 92 into the cooling plenum 74 and thence through the front end of the evaporator assembly 80 along with the air stream from the freezer compartment `48 and most of the air stream passing through the return passageway 222.

The amount of cooling and temperature of operation of the compartment 54 is determined by the relative positionof the arcuate plate 241 of the assembly 237 with respect to openings 235, 236 as established by positioning of control knob 238 with respect to suitable indicia on the control panel.

In. the above-described arrangement a small amount of the subfreezing air controlled by the damper 134 is bled through a circuit constituted by the groove 232 in member 150, the tubular extension 230 on the plate 152 and concentrically aligned opening 228 on the upper side extension 224 on the member 148. The opening 228 directs air through the liner port 233, as shown in FIG- URES l and 4, and thence interiorly of the compartment 54, This subfreezing air stream flows around theclosed container or meat tender 234 located at one side of the compartment 54. i

This bypass circuit for the subfreezng air is located immediately after the valve when the air stream is still very cold so that the contents` of the meat tender will be maintained at 28-30 F. which is 4 to 8 F. below the temperature of the flowing cold intermediate compartment 54. The bleed of subfreezing air supplements the compartment cooling action of the air ow controlled by the damper assembly 237 and is returned to the cooling plenum 74 in the same manner. u.

In the working embodiment of the invention, approximately one-fourth of the air flow through the compartment 54 is provided by the meat tender inlet and threefourths of the cooling effect is provided by airflow through the manually operated damper assembly 237. p

Another feature of the present invention is the manner in which humidity condensation is controlled in chamber 52. Since forced draft cooling' flow through chamber 52 is precluded, the moisture level in articles stored therein and any excess moisture entering into chamber 52 through lower cabinet opening 63 will condense on the cold-walls of the chamber 52 and it will be normal and desirable that moisture beads collect on the sides and rear walls of the liner 30. When the refrigerator is operated in humid climates, the amount of collected moisture will increase and, to prevent an undesirable accumulation of moisture on the underside of the divider 50 and an intermediate shelf 305 or any other horizontally disposed surfaces within the compartment 52, the solid state motor control 290 can be set in a manner more specifically set forth in the copending Canter application to increase the speed of operation of a fan 306 to produce a greater discharge of air upwardly through a vertical duct 308 from a lower louvered inlet 310. This increases the velocity of air flow from an intermediate discharge outlet 312 and a top outlet 314 in duct 308. This increased velocity of air flow will sweep any excessive moisture off the undersides of horizontal collecting surfaces before any substantial condensate accumulation occurs capable of forming globules of water that might drip through the chamber 52 in an undesirable manner.

The air ow from the outlets 312, 314 sweeps forwardly of the compartment 52 and thence is diverted downwardly and across the bottom 38 of the liner 30 to be returned to the fan inlet as bestseen in FIGURES 2 and 3. As the air `flows across the bottom 38 any excess moisture therein Will be condensed on the bottom surface and will then drain through an outlet fitting 316 connected by a conduit 318 to drain into the condensate pan 104 as is the moisture collected by the drain pan 98. The moisture collected in the condensate pan will Vthen `be reevaporated and distributed into thejarnbient air out side the cabinet by the condenser fan 112.

The excessmoisture collected on the sides, and back of the liner will drain downwardly to be collected by the bottom and thereafter flow through the outlet 316 and conduit 318 into thepan 104. A-bottomkhydrator drawer 320 in chamber 52 will direct the greatest part of air flow across bottom 3 8; v Y

Under ordinary ambient conditions where only a Inoderate relative humidity exists, it is often found that the fan 306 can be operated at a'very'low speed thereby -to retain a humidity level Within the chamber 52 capable `of preserving foods against dehydration and yet one which will preclude a moisture drippage' problem or an otherwise generally clammyl condition within the chamber 52.

The above-described'domestic refrigerator' and its mode of operation retain the benefits of distinct and separate freezer, high humidity and a quick chill or flowing cold type compartments. It vdoes so` by balancing air flow through a first fluid flow circuit generally through the freezer compartment, a separate and distinct air circuit throughV a-closed ductisystem and a third air circuit that represents abranch or diverted air ow directly through the flowing cold compartment. f v The cooling ofthe refrigerator-volume is produced by asingle evaporator assembly located within a cooling plenum open to each of -the' distinct air circulating systems and close temperature rangeswithin` each of the compartments-are obtained with low cost, readilyavailable, thermostatically operated, control assemblies of thetype commonly found on existingYdomesticfrefrigeration devices.

Moreover, the above-described system accomplishes the important. aim of maintaing an operating environment wherein frost buildup-only occurs on a hidden evaporator surface that is periodically automatically defrosted to remove moisture from the system.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is understood that other forms might be adopted without departing from the spirit of this invention.

What is claimed is:

1. In a plural compartment refrigerator, means forming an insulated'refrigerator cabinet having a freezer compartment, means forming an above freezing compartment in said cabinet separated intoaV sealedfhumidified chamber and convectively cooled chamber, means defining a cooling plenum in said cabinet having 'a cold source therein maintaining the temperature-in said cooling plenum substantially below freezing, first air distributing means for circulating air from said plenum through said freezer compartment for maintaining it Ibelow freezing, said first air distributing means including a fan for drawing dry, subfreezing air from said plenum, said first air distributing means further including a vertically directed outlet duct communicating air `discharged from Said fan with said' freezer compartment, second air distributing means receving a portion of the air flow from said fan, valve means in said second air distributing means for proportioning the amount of air flow in said second air distributing means in accordance with the temperature in said high humidity chamber, said second air distributing means further including a duct system surrounding said humidified chamber in heat transfer relationship therewith to cool said humidified chamber while precluding forced draft dehydration therein, means including a counterflow heat exchanger for concurrently warming air flow in said second air distributing means prior to passage thereof into said duct system while recooling air in said second air distributing means after it cools said humidified chamber, a return duct receiving said recooled air, a fiow controller communicating said return duct with the interior of said cnvectively cooled chamber and operative to divert a predetermined amount of the return air cooled by said counterflo-w heat exchanger means interiorly of said convectively cooled chamber, and means for directing the diverted air flow in said convectively cooled chamber back to said cooling plenum.

2. In a plural compartment domestic refrigerator the combination of means forming an insulated cabinet, means including an insulated partition member separating said cabinet into a top space and a bottom space, a divider plate within said Ibottom space dividing it into first and second chambers, means for sealing said second chamber to maintain a high humidity level therein, means dening a cooling plenum within said top space, means including a refrigerant evaporator in said cooling plenum defining a below freezing cold source for reducing the temperature in said top and bottom spaces within said cabinet, first air circulation means for circulating air through said top space to maintain the temperature in said top space below freezing, said first air circulating means including a first inlet into said plenum from said top space and an outlet from said plenum and further including fan means for drawing air' from said outlet for discharge into said .top space, second air circulation means within said insulated cabinet including duct means for diverting cold, dry air from said fan downwardly of said cabinet, an inner liner enclosing said second chamber, a liner cooling duct system overlying said liner in heat transfer relationship therewith for cooling said second chamber by heat transfer across said liner while precluding passage of cold dry air directly through said second chamber, a counterfiow heat exchanger includv ing means defining a first passageway for receiving air limit heat transfer thereacross, a partition within said liner passing downwardly of said cabinet and directing it to said liner cooling duct system, said counterfiow heat exchanger including a second passageway for receiving air from said liner cooling duct system and passing it in counterflow relationship with flow through said first passageway, a heat transfer plate within said counterfiow heat exchanger exchanging heat between air flow through said first and seC- ond passageways causing air to be warmed prior to its passage into said liner cooling duct System and return air from said liner cooling duct system to be cooled, means defining a return duct communicating said second passageway of said counterflow heat exchanger with said cooling plenum, means for diverting a part of the air flow through said return duct into said first chamber and means defining an opening between said first chamber and said cooling plenum to pass air from said first chamber back into said plenum chamber thereby to establish a convective flow pattern within said first chamber for maintaining the temperature therein above freezing.

3. In a plural compartment domestic refrigerator, an outer shell having a top, bottom, spaced apart side walls and a rear wall joining said side walls, a liner located within said outer casing in spaced relationship therewith, thermal insulation means between said shell and said liner to connected thereto for separating said liner into first and second compartments, means dividing said second compartment into first and second chambers, means sealing said second chamber for maintaining a high humidity therein, a cooling source, means for circulating air across said cooling source and through said first compartment to maintain said first compartment at a temperature below freezing, means for circulating dry air from said cooling source to said second compartment while precluding dry air flow through said second chamber, thereby to maintain the humidity level therein, said last mentioned means including a duct system located be'tween said liner and said shell and in spaced parallel relationship to said side walls, rear wall and bottom of said shell for circulating cooling air across said liner to cool Said second humidified chamber by heat transfer across said liner, said duct system including a counterflow heat exchanger having a heat transfer plate and means defining a first passageway for directing cold air from said cooling source into said duct system, said counterflow heat exchanger including means defining a second passageway for receiving air from said duct system following cooling of said second chamber, a return duct receiving air from said second passageway including means for directing a first predetermined portion of said return air through said first chamber for convectively cooling said first chamber, said heat transfer plate exchanging energy between air flow through said first and second passageways of said counterflow heat exchanger for warming air fiow from said cooling source prior to its passage into said liner cooling duct system and for cooling the temperature of return air flow from said liner cooling duct system prior to its passage through said first chamber, said return duct directing a second predetermined proportion of said return air passing in bypassed relationship with said first chamber, control means in said return duct to regulate the amount of air fiow from said return duct into said first chamber, and means for returning air from said first chamber across said cooling source.

4. A plural compartment domestic refrigerator com- 1 5 prisng an outer shell having side walls, a rear wall joining said side Walls, a top and a bottom, a liner located within said cabinet shell including planar segments in spaced parallel, relationship with said outer casing means including an insulated horizontal partition Within said liner dividing said liner into a top compartment and a bottom compartment, a divider plate within said bottom compartment dividing it into first and second chambers, rst closure means on said cabinet for closing said top compartment, second closure means on said cabinet including a sealing surface engageable with said divider plate for closing said second compartment and sealing said first and second chambers therein one from fthe other, means dening a cooling plenum within said top compartment, a refrigerant evaporator within said cooling plenum, means including a compressor and a condenser in serial refrigerant flow relationship with said evaporator to reduce the temperature within said cooling plenum, means forming a first inlet into said cooling plenum in Comunication with said top compartment, an outlet from said cooling plenum, fan means for drawing air from said plenum outlet and discharging it into said top compartment for convective cooling therethrough, control means for operating said compressor and said fan means for maintaining the temperature in said top compartment below freezing, an outlet duct for receiving another part of dry cold air discharged from said fan means, thremally responsive valve means in said outlet duct including means for sensing the temperature of said liner in surrounding relationship with the second chamber of said bo'ttom compartment for controlling the amount of air passing through said outlet duct, fluid circulating means including a liner cooling duct system overlying said liner to surround said second chamber for cooling it While precluding forced draft dehydration, a return duct for returning air from said liner cooling duct system back to said cooling plenum, a counter flow heat exchanger located rearwardly of said liner between it and said rear Wall including a first passageway for directing air oW from said valve means into said liner cooling duct system, said counter fiow heat exchanger further including means forming a second passageway therethrough for, directing air ow from said liner cooling duct system into said return duct, said heat exchanger including a heat transfer surface therein between said first and second passageways therethrough located in spaced parallelism with the rear Wall of said liner and being separated therefrom by said second heat exchanger passagway, said evaporator in said cooling plenum being operated to maintain an air temperature therein substantially below freezing, said fan means directing said substantially below freezing air through said outlet duct and said valve means into said first passageway of said heat exchanger, return airow through said second heat exchanger passageway being directed in counter ow relationship to the air fiow through back to said cooling plenum thereby to establish convective air ow patterns within said first chamber for cooling articles therein.

References Cited UNITED STATES PATENTS 2,285,946 6/ 1942 Kalishes 62-186 2,442,188 5/ 1948 Bauman 62-419 2,462,279 2/ 1949 Passman 62-187 3,232,071 2/ 1966 Wallenbrock 62-419 3,375,677 4/1968 Bright 62-419 3,3 94,557 7/ 1968 Kronenberger 62-419 WILLIAM I. WYE, Primary Examiner U.S. C1. XR.

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