US3050955A - Multi-temperature refrigerator - Google Patents

Description

Aug. 28, 1962 D. A. SOLLEY, JR., ET AL 3,050,955

MULTI-TEMPERATUREREFRIGERATOR 4 Sheets-Sheet 1 Filed Dec. 19, 1960 ,4 IN V EN TORS DOUGLAS A. SOLLEY J'R BYE KENNETH A. ROBBIE THEIR ATTORNEY Aug. 28, 1962 D. A. SOLLEY, JR, ET AL 3,050,955

MULTI-TEMPERATURE REFRIGERATOR 4 Sheets-Sheet 2 Filed Dec. 19, 1960 INVENTORS DOUGLAS A. SOLLEY 3R BY 9 KENNETH A. ROEEAE THEN-=1 ATTORNEY Aug. 28, 1962 D A. SOLLEY, JR., ET AL 3,050,955

MULTI-TEMPERATURE REFRIGERATOR Filed Dec. 19, 1960 4 Sheets-Sheet 5 FIG. 3

IN V EN TORS @KENNETH A. ROB5\E T HE l R ATTORNEY DOUGLAS A. SOLLEY IR.

1962 D. A. SOLLEY, JR., ETAL 3,050,955

MULTI-TEMPERATURE REFRIGERATOR Filed Dec. 19, 1960 4 Sheets-Sheet 4 IN VEN TORS DOUGLAS A. SOLLEY T ZKENNETH A. Rosana.

THEJR ATTORNEY United States Patent 3,050,955 MULTI-TEMPERATURE REFRIGERATOR Douglas A. Solley, In, Fern Creek, and Kenneth A. Robhie, Louisville, Ky., assignors to General Electric Company, a corporation of New York Filed Dec. 19, 1960, Ser. No. 76,538 7 Claims. (Ci. 62-455) The present invention relates to a refrigerator comprising two or more compartments maintained at different temperatures by means of air streams circulated over a single evaporator unit. It is more particularly concerned with an improved defrostable evaporator unit for such a refrigerator.

In multi-temperature household refrigeratorathere is normally provided at least one compartment operating at temperatures somewhat above freezing for the storage of unfrozen or fresh foods and another compartment operating at temperatures substantially below freezing for the storage of frozen foods. When a single evaporator is used for maintaining one compartment at sub-freezing temperatures and another compartment at temperatures above freezing, the evaporator is operated at a temperature somewhat below that required in the lower temperature compartment and both compartments are cooled by the circulation of air from the compartments over the evaporator. The present invention is specifically concerned with a refrigerator of this type and has as its principal object the provision of an improved cooling system for maintaining the different compartments at their desired operating temperatures.

A more specific object of the invention is to provide an improved evaporator for the forced air cooling of the various compartments of. a multi-ternperature refrigerator.

A further object of the invention is to provide an improved evaporator structure -for the forced air cooling of two or more compartments, the evaporator being so constructed and arranged that it will accommodate the normally heavier frost load from the compartment or compartments operating at above freezing temperatures and also provide the required cooling for a freezer compartment.

Another object of the invention is to provide an improved refrigerator including a freezer compartment, a fresh food storage compartment, a third compartment or area operating at a temperature somewhat below that of the fresh food storage compartment and an improved forced air cooling system for refrigerating the respective compartments by means of a single evaporator unit.

Further objects and advantages of the present invention will become apparent from the following description and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In accordance with the present invention there is provided a combination refrigerator including a fresh food storage compartment and a freezer compartment. In the preferred form of the invention, there is also provided a third compartment operating at a temperature somewhat below that of the fresh food storage compartment for the unfrozen storage of meats and the like. For the purpose of maintaining all of the compartments at the desired operating temperatures, there is provided a forced air circulating system by means of which air streams from the compartments are circulated over a single evaporator unit of improved construction. This unit comprises a housing for isolating the evaporator from the compartments and a tubular evaporator within the housing comprising a first section extending along one wall of the housing, a second section extending along the opposite wall and a combination partition and accumulator between the two sections dividing the housing into two separate chambers. Preferably the partition is in the form of a roll-forged accumulator. One of the evaporator chambers is pro.- vided with air circulating means for circulating air from the freezer compartment over one section of the evaporator and in direct contact with one side of the accumulator partition while the other chamber is provided with air circulating means for circulating air from the fresh food or above freezing compartment or compartments over the section of the evaporator contained therein and in contact with the other side of the accumulator partition. The two sections of the evaporator, the accumulator, a compressor and a condenser are connected in series refrigerant flow relationship and the compressor is operated by a compressor control switch responsive to the temperature of the refrigerant flowing from the last section of the evaporator into the partition accumulator. A fan for circulating air from the freezer compartment is normally controlled to operate only when the compressor is operating on a refrigerating cycle while the fan for circulating air from the fresh food compartment is normally controlled by a switch responsive to the temperature of the air in that compartment so that it can operate whether or not the compressor is operating at the time the temperature sensing element of the fresh food switch calls for refrigeration. For the periodic defrosting of the evaporator unit, heating means are provided for warming the evaporator sections and accumulator partition to defrosting temperatures and the control circuitry is such that during defrost neither of the fans can operate. The defrosting cycle is terminated by a defrost control switch in response to an above freezing temperature of the partition accumulator.

For a better understanding of the invention, reference may be had to the accompanying drawings in which:

FIG. 1 is a front elevation, with the closure members removed, of a refrigerator cabinet incorporating an em bodiment of the present invention;

FIG. 2 is a side elevational view taken generally along line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a horizontal sectional view taken along line 4-4 of FIG. 3; and

FIG. 5 is a diagrammatic illustration of the refrigeration system and evaporator unit of the present invention.

With reference to the drawing there is shown apreferred embodiment of the present invention in the form of a household refrigerator cabinet comprising an upper storage compartment 1 for the storage of fresh or unfrozen food-s, afreezer compartment 2 located below the compartment 1 and separated therefrom by aninsulated partition 3 and a motor-compressor compartment 4 at the bottom of the cabinet. The access opening to the fresh food compartment 1 is closed by means of a door 5 While the access opening to thefreezer compartment 2 is closed by a drawer front 6 forming part of a sliding drawer structure including baskets 7 for the storage of frozen foods. A horizontal divider 8, which may also be used as a shelf, extends across the upper compartment 1 in spaced relationship with the bottom wall 9 thereof. This divider and a vertical divider 11 cooperate to define with the adjacent walls of the compartment \1storage areas 14 and '15 substantially separate from the main compartment 1. Two shallow draws, 68 and 68a, in the side walls of the liner of compartment'l are arranged outboard of the supports for horizontal divider 8 so that means of air communication between compartment 1 andareas 14 and 15 are provided. Thearea 14 is designed to operate at a temperature somewhat below the temperature maintained within the compartment 1 for the proper refrigeration of fresh meats and the like stored in apan 16 slidably supported in the area below the divider 8. A similar pan 117 in the area is provided for the storage of fruits, vegetables, and the like.

The Various compartments and storage areas are maintained at the desired refrigerating temperatures by means of asingle evaporator unit 20. In the illustrated embodiment of the invention, this unit is disposed in the rear portion of thefreezer compartment 2. As is shown in greater detail in FIGS. 3 and 4 of the drawing, it comprises a substantially closedhousing 21 including a front wall 22 arear wall 23 and a slopingbottom wall 24. Thehousing 21 isolates anevaporator 25 contained within the housing from the contents of thefreezer compartment 2. Theevaporator 25 comprises arefrigerating tube 26 and adefrost tube 27 extending parallel to the refrigerating tube and in heat exchange relationship therewith. One section of the evaporator indicated by thenumeral 28 is arranged in the form of a plurality of vertically elongated coils along and spaced from thefront wall 22 of the housing and constitutes the principal means for cooling air circulated from the freezer compartment. The other section indicated by thenumeral 29 is arranged in similar coil form. along and spaced from therear wall 23 of the housing and serves to cool air circulated from the upper or fresh food storage compartment 1. A vertically extending combination partition and accumulator 31) extending the full height and width of thehousing 21 between and spaced from theevaporator sections 28 and 25 divides the housing into front andrear chambers 31 and 32. This partition accumulator prevents mingling of the air streams from the two compartments and also assists in the cooling thereof. It is preferably a roll-forged structure of the well known type comprising bonded sheets formed to provide a waflie grid pattern of vertically and horizontally extending refrigerant passages between the sheets for the storage of a substantial quantity of liquid refrigerant at relatively high pressures without distortion.

The evaporator sections and theaccumulator 3%) form part of a refrigerating system or circuit including acompressor 33 and acondenser 34 disposed in themachinery compartment 4. By means of suitable refrigerant flow means, thecompressor 33, thecondenser 34, acapillary flow restrictor 35, therefrigerant tube portion 26 of theevaporator sections 29 and 23 and the accumulator are connected in closed series refrigerant flow relationship for normal refrigerating operation. While no restriction or other fiow control means is provided in the cooling portion of the system, there is an inherent pressure drop between the first evaporator section and the accumulator so that the accumulator and hence the entire partition normally operates at a slightly lower refrigerating temperature than the evaporator sections. During normal refrigerating operation, the evaporator unit operates continuously at sub-freezing temperatures so that moisture from the air streams circulating over the evaporator sections and the accumulator partition deposits thereon in the form of frost. For the purpose of defrosting the unit, hot refrigerant gas means are provided for periodically warming the unit to a defrosting temperature. In the illustrated embodiment of the invention, this is accomplished by means of hot refrigerant gas circulated from thecompressor 33 through thedefrost tube 27 forming part of the evaporator sections and thedefrost tubing 36 forming part of the roll-forgedpartition accumulator 30 employing the defrost circuit more fully described in Patent 2,928,256, Nonomaque, issued March 15, 1960, and assigned to the same assignee as the present invention. The inlet end of the defrost circuit is connected through a normally closed solenoid valve 38 to the refrigerating circuit between thecompressor 33 and thecondenser 34 so that upon opening of the valve 38, hot compressed refrigerant from the compressor will flow first through aconduit 40 in heat exchange relationship with the slopingbottom wall 24 4% of thehousing 21, through thedefrost tube 27 forming part of theevaporator sections 28 and 29 and thedefrost tube 36 forming part of theaccumulator 30. The hot refrigerant condensed in thedefrost tubing 27 and 36 returns to the compressor through a capillary flow restrictor 42 connected to thesuction line 43 between theaccumulator 30 and thecompressor 33. The defrost water collects in the slopingbottom wall 24 ofhousing 20 and is disposed of through adrain 41 which communicates with both sides of the partition and accumulator Git.

During normal or refrigerating operation of the refrigerator, air from the fresh food compartment 1 is circulated through therear housing chamber 32 and air from thefreezer compartment 2 is circulated through thefront housing chamber 31. The air circulating means for refrigerating the fresh food compartment comprises asupply duct 46 extending vertically along the rear wall of compartment 1 and having itsinlet end 47 connected to the rear ofchamber 32 adjacent the top and one end wall thereof and itsoutlet 48 opening into the compartment 1 adjacent the top and one side wall of that compartment. Areturn duct 50 having its inlet in the rear wall ofstorage area 15 connects compartment 1 with the opposite end of thechamber 32. Afan 51 at the inlet end of theduct 50 withdraws air from the fresh food storage compartment and circulates that air through thechamber 32, the cooled air returning to the storage compartment 1 through theduct 46. Adecorative baifle 4 4 deflects the air stream frominlet 48 along the top wall of compartment 1. Thebaiiie 4 3 also acts as a shield for a light 45.

An adjustable outlet as in theduct 46 is provided for admitting a relatively large flow of cold air into thestorage area 14 in order to maintain the contents of that area at a temperature somewhat below that normally maintained in the fresh food compartment '1. This outlet is shown as having a slidingdamper 49a for controlling the amount of air diverted to that compartment. The air stream passing througharea 14 is primarily vented throughliner draw 68 in the adjacent side wall to the compartment 1, Where it then mixes with the air delivered at the top of compartment 1 throughopening 43. This combined air flow then passes primarily through liner draw 6th: in the opposite side wall to return to thefan inlet 51.

Air from thefreezer compartment 2 is circulated through thefront chamber 31 of the evaporator unit by means of afan 52 positioned in an air inlet opening 53 provided in thefront wall 22 of the housing. This air stream flows out of thechamber 31 throughslots 54; andlouvered openings 55 provided at the opposite ends of the housing.

The electrical control circuitry for controlling the operation of the refrigerator in its normal and defrost operation is shown in FIG. 5 of the drawing as including adefrost control switch 56, acompressor control switch 57 and a fresh foodfan control switch 58 for controlling the operation of thefan 51. The operation of thecompressor control switch 57 is controlled by the temperature of the outlet end of the second orfreezer section 28 of the evaporator. It is connected in series with thecompressor 33 across thesupply lines 60 and 61. The compressor is energized whenever theswitch 57 senses a specific maximum, but below freezing, temperature of the outlet end of theevaporator section 28 and is de-energized by opening of theswitch 57 whenever that portion of the evaporator reaches a predetermined minimum temperature. Preferably thecontrol switch 57 is set to maintain the evaporator within a temperature range a few degrees below that desired in thefreezer compartment 2.

Thedefrost control switch 56 is a two position switch in which theswitch arm 62 can move either to a normal refrigerating position in engagement with the switch confore measures compressor running time.

tact 63 or to a defrost position in engagement with thecontact 64. Whenswitch 56 is in its normal or refrigcrating position, in which theswitch arm 62 engages thecontact 63, thefreezer fan 52 is connected across the supply lines 6!} and 61 through thedefrost control switch 56, theswitch 56 and the fan being connected in parallel with thecompressor 33. Thefan 52 is then energized whenever the compressor is energized by closing of theswitch 57. The fresh food fan circuit includes thecontact 63 of the defrost control switch and aswitch 58 arranged so that its operation is controlled by the temperature of the air in the fresh food compartment. As shown in FIG. 1 of the drawing theswitch 58 is preferably positioried in the upper portion of the compartment 1 on the opposite side of the compartment from theinlet 48. Itssensing bulb 58a is positioned behind thebaffle 44 and is shielded from the direct flow of air frominlet 48 byrib 44a forming part ofbaffle 44.Switch 58 is designed to start and stop thefan 51 in response to changes in the temperature of the storage compartment 1 in order to maintain that compartment within, for example, a temperature range of from toF. Fan 51 operates independently of the operation of either thecompressor 33 or thefreezer fan 52 during normal refrigerating operation of the system.

Any suitable means may be employed for periodically actuating theswitch 56 to initiate a defrost cycle. In the illustrated embodiment of the invention, atimer 66 is employed. This timer is connected acrosssupply lines 60 and 61 in parallel with thecompressor 33 so that it runs only when the compressor is operating and there- After a predetermined total running time for the compressor, the timer is designed to trip thedefrost switch 56 to its defrost position and thereby energize the solenoid valve 38 through thedefrost contact 64. The compressor remains under the control ofswitch 57 and when this switch is closed the compressor will operate to direct a flow of hot compressed refrigerant gas through the defrost circuit. For the purpose of terminating the defrost cycle after complete warming of the evaporator unit to defrosting temperatures, switch 56 includes asensing bulb 67 or equivalent temperature sensing means which senses the temperature of thepartition accumulator 30 and which trips theswitch 56 to return it to its normal refrigerating position when the accumulator has reached an abovefreezing temperature.

During normal operation of the refrigerating system, the compressor and thefreezer fan 52 cycle on and off in response to the temperature of the outlet end of the freezer portion or section of the evaporator to maintain the entire evaporator unit at below freezing temperatures which assure the desired temperature in thefreezer compartment 2. Thefan 52 circulates air from the freezer compartment inwardly through theinlet 53 in the front wall of the housing and into heat exchange relationship with both thefreezer section 28 of the evaporator and also with the entire front surface of theaccumulator partition 30. Much of the moisture in the air circulating through thefreezer chamber 31 is deposited on the relatively colder surface of theaccumulator partition 30 with the result that the evaporator section remains relatively free of frost for a longer period of time so that that section can operate at maximum etficiency.

Operation of the compressor also maintains the freshfood evaporator section 29 at sub-freezing temperatures so that its cooling effect is available to the fresh food compartment 1 whenever required. When the temperature of the fresh food compartment reaches a predetermined maximum of for example 40 F.,switch 58 completes the circuit energizingthefresh food fan 51. Air from compartment 1 is then circulated through thechamber 32 in contact with both theevaporator section 29 and the rear surface of the accumulator 39. With the accumulator again providing a surface which is the focal point for the collection of frost from the air streams, the rate of frost accumulation or formation on theevaporator section 29 is retarded so that its efiiciency is maintained over a longer period of time.

The cooled air leaving thechamber 32 through theduct 46 passes into the upper storage compartment through both the adjustable outlet communicating with thestorage area 14 and through theupper outlet 48. By suitably setting the adjustable outlet communicating with thearea 14, the volume of air circulated through that area as compared with the amount of air issuing from theoutlet 43 can be regulated to maintain the contents of the area 14- at a temperature a few degrees lower than those obtainable in the remaining portions of the compartment 1.

After a predetermined period of compressor operation, thetimer 66 is set to initiate a defrost cycle by tripping theswitch arm 62 into its defrost position engaging thecontact 64. This opens the solenoid valve 38 so that the compressor will then pump hot compressed refrigerant through the defrost circuit into warming contact with the surfaces of the evaporator unit. The warming action of the defrost gas on the evaporator prevents thecompressor switch 57 from opening and the compressor continues to operate until an above freezing temperature is sensed by thebulb 67 arranged in sensing contact with theaccumulator partition 30, which, because it is the focal point of most of the frost accumulation, is the last portion of the evaporator circuit to be warmed by the defrost gas, and is therefore the last to become warmed to defrosting temperatures. When thebulb 67 trips thedefrost control switch 56 and returns it to its normal or refrigerating position, the operation of the compressor is returned to the control of thecompressor control switch 57. As this switch is now sensing a defrost temperature that is well above freezing, the compressor will continue to operate through a normal refrigerating cycle untilswitch 57 again senses the predetermined low or compressor off temperature.

It will be obvious of course that the defrost means need not be in the form of a circuit for circulating hot compressed refrigerant into warming contact with the evaporator unit. For example, an electrical resistance heater can be arranged in warming contact with the refrigerant tubing and theaccumulator 30 in place oftube 27. When electrical resistance heating is used the solenoid valve 38 and associated circuitry is omitted and the resistance heater is connected to the supply lines through thedefrost contact 61. If the heat supply is sufficient to overcome the refrigerating capacity of the system, the compressor may be allowed to continue to operate during the defrost operation. Otherwise, the compressor is connected across thesupply lines 60 and 61 in the same manner asfan 52 so that the compressor is energized only when the defrost control switch is in its normal or refrigerating position in which theswitch arm 62 engagescontact 63.

From the foregoing it will be seen that there has been provided an improved multi-temperature refrigerator particularly characterized by an improved evaporator unit which provides in a single unit both means for separating the air streams from the fresh food and freezer compartments and means for limiting the rate of accumulation of frost on the evaporator sections thereby maintaining the loss of overall efiiciency at a minimum for a longer period of time. In other words by separating the freezer and fresh food air streams and by providing an accumulator partition for collecting the major portion of the moisture in both air streams, the air streams flowing over the two sections can be maintained at the desired temperatures for longer periods of time.

While there has been shown and described a particular embodiment of the present invention, it is to be understood that the invention is not limited to the embodiment but is intended by the appended claims to cover all modifications within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. A household refrigerator including a freezer compartment for the storage of frozen foods and a fresh food compartment for the storage of foodstuffs at abovefreezing temperatures, an evaporator unit in said freezer compartment for refrigerating both of said compartments, said unit including a housing including opposed walls, an evaporator formed from a continuous coiled tubing and comprising a first section extending along one of said walls and a second section extending along the other of said walls, a vertical partition having refrigerant passages therein disposed between said sections and dividing said housing into a first chamber and a second chamber, said sections and said refrigerant passages being connected in series refrigerant flow relationship whereby said partition operates at a lower temperature than said sections, and duct and fan means for circulating air from said fresh food compartment through said second chamber and from said freezer compartment through said first chamber.

2. A household refrigerator including a freezer compartment for the storage of frozen foods and a fresh food compartment for the storage of foodstuffs at abovefreezing temperatures, an evaporator disposed in said freezer compartment for refrigerating both of said compartments, a housing enclosing said evaporator, said evaporator comprising a first section extending along one wall of said housing and a second section extending along the opposite wall of said housing, a vertical partition having refrigerant passages therein disposed between said sections and dividing said housing into a first chamber and a second chamber, said first and second sections and said refrigerant passages being connected in series refrigerant flow relationship whereby said partition operates at a. lower temperature than said sections, and duct and fan means for circulating air from said fresh food compartment through said second chamber section and from said freezer compartment through said first chamber.

3. A household refrigerator including a freezer compartment for the storage of frozen foods and a fresh food compartment for the storage of foodstuffs at abovefreezing temperatures, an evaporator for refrigerating both of said compartments, a housing enclosing said evaporator, said evaporator comprising a first section extending along one of said walls of said housing and a second section extending along the opposite wall of said housing, a roll-forged accumulator forming a vertical partition between said sections dividing said housing into a first chamber and a second chamber, said sections and said accumulator being connected in series refrigerant flow relationship whereby said partition operates at a lower temperature than said sections, and duct and fan means for circulating air from said fresh food compartment through said second chamber and from said freezer compartment through said first chamber.

4. A refrigerator cabinet comprising an upper fresh food compartment for the storage of unfrozen foods and a lower freezer compartment for the storage of frozen foods, closure means for closing the access openings to said compartments; an evaporator structure disposed in the rear portion of said freezer compartment; said evaporator structure comprising a housing including front and rear walls, a freezer evaporator section disposed along the front wall of said housing, a fresh food evaporator section disposed along the rear Wall of said housing, a vertical partition between said evaporator sections dividing said housing into front and rear chambers, said partition including interconnected passageways forming a refrigerant accumulator; said housing front wall having air inlet and outlet openings therein, a freezer fan in said inlet opening for circulating air from said lower compartment through said front chamber and back into said lower compartment, means for circulating air from said upper compartment through said rear chamber comprising a first duct extending from one end of the rear chamber of said housing upwardly along the outer surface of the rear wall of said fresh food compartment and having an outlet communicating with said fresh food compartment adjacent the top and one side wall thereof, a second duct having its inlet end in said fresh food compartment rear wall adjacent the bottom and opposite side wall of said fresh food compartment and its outlet end connected to the other end of said housing rear chamber, a fresh food fan associated with said second duct for circulating air from said fresh food compartment through said second duct into said rear chamber and back into said fresh food compartment through said first duct; horizontal and vertical dividers in said upper compartment forming with the side and bottom walls of said fresh food compartment side-by-side storage areas, one of said areas being in front of said first duct, said second duct inlet communicating with the other of said areas, an adjustable air outlet in said first duct for introducing air from said duct into said one area for maintaining said area at a lower temperature than the remaining portions of said fresh food compartment, said dividers having their front edges spaced from said closure member for circulation of air from both of said first duct outlets to said second duct inlet; a compressor, a condenser and refrigerant flow means connecting said compressor, condenser, fresh food evaporator section, freezer evaporator section and accumulator in series refrigerant flow relationship, defrost means for periodically warming said sections and said partition to defrosting temperatures; electrical control means for controlling the operation of said fans, said defrost means and said compressor comprising a compressor circuit including a freezer control switch operative in response to the temperature of said freezer evaporator section adjacent the outlet end thereof for normally maintaining both of said sections within a below-freezing temperature range; a two-position defrost control switch movable between a normal refrigerating position and a defrost position; a freezer fan circuit including, in series connection, said freezer control switch and said defrost control switch in its normal position to energize said freezer fan when said compressor is energized by closing of said freezer control switch; a fresh food fan circuit including, in series connection, said defrost control switch in its normal position and a fresh food temperature control switch operable in response to the temperature of said fresh food compartment for maintaining said fresh food compartment within an above-freezing temperature range; a defrost timer for periodically moving said defrost control switch to its defrost position to energize said defrost means; a timer circuit connecting said timer in series with said freezer control switch for energization of said timer only when said compressor is energized, and means responsive to an above-freezing temperature of said vertical partition for restoring said defrost control switch to its normal position.

5. A refrigerator cabinet comprising a first compart: ment for the storage of fresh unfrozen foods and a second compartment for the storage of frozen foods, closure means for closing the access openings to said compartments; an evaporator structure disposed in said second compartment adjacent one wall thereof; said evaporator structure comprising a housing including front and rear walls, a freezer evaporator section disposed along the front wall of said housing, a fresh food evaporator section disposed along the rear Wall of said housing, a vertical partition between said evaporator sections dividing said housing into front and rear chambers, said partition including interconnected passageways forming a refrigerant accumulator; said housing front wall having aid inlet and outlet openings therein, a freezer fan in said inlet opening for circulating air from said second compartment through said front chamber and back into said second compartment; means for circulating air from said first compartment through said rear chamber comprising a first duct having its inlet end connected to the rear chamber of said housing and having an outlet communicating with said first compartment adjacent the top and one side wall thereof, a second duct having its inlet end connected to said first compartment rear wall adjacent the bottom and opposite side walls of said first compartment and its outlet end connected to said housing rear chamber, a fresh food fan associated with said second duct for circulating air from said first compartment through said second duct into said rear chamber and back into said first compartment through said first duct; means including dividers in said first compartment forming a storage area in said first compartment, said first duct including an adjustable air outlet introducing air from said duct into said area for maintaining said area at a lower temperature than the remaining portions of said first compartment, said dividers having their front edges spaced from said closure member for circulation of air from said adjustable air outlet to said second duct inlet; a compressor, a condenser, and refrigerant flow means connecting said compressor, condenser, first evaporator section, second evaporator section and accumulator in series refrigerant flow relationship, defrost means for periodically warming said sections and said partition to defrosting temperatures, electrical control means for controlling the operation of said fan, said defrost means and said compressor comprising, a compressor circuit including a freezer control switch operative in response to the temperature of said first evaporator section adjacent the outlet end thereof for controlling the energization of said compressor for normally maintaining said sections within a below-freezing temperature range, a freezer fan circuit including said freezer control switch to energize said freezer fan when said compressor is en ergized by said freezer control switch, a fresh food fan circuit including in series connection said defrost control switch in its normal position and a first compartment temperature control switch operable in response to the temperature of said first compartment for maintaining said first compartment within an above-freezing temperature range; means for periodically energizing said defrost 1% means, and means responsive to an above-freezing teni perature of said vertical partition for de-energizing said defrost means. 6. An evaporator unit for forced air refrigeration of separate storage compartments comprising a housing, an evaporator disposed in said housing and comprising first and second sections, a roll-forged accurnu'lator in said housing forming a partition between said sections and dividing said housing into two chambers each containing one of said sections, means connecting said first sections, said second section and said accumulator in series refrigerant flow relationship, air circulating means for connecting said chambers respectively with said compartments, means for periodically warming said unit to defrost temperatures, and means responsive to an abovefreezing temperature of said accumulator for terminating operation of said warming means.

7. An evaporator unit for forced air refrigeration of separate storage compartments comprising a housing, an evaporator disposed in said housing and comprising first and second sections, a roll-forged accumulator in said housing forming a partition between said sections and dividing said housing into two chambers each containing one of said sections, means connecting said first section, said second section and said accumulator in series refrigerant flow relationship whereby said accumulator tends to operate at a lower temperature than said sections so that moisture in an air stream circulated through either of said chambers preferentially collects on a surface of said partition, and air circulating means for connecting said chambers respectively with said compartments.

References Cited in the file of this patent UNITED STATES PATENTS

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