US2866323A - Forced air cooled refrigerator - Google Patents

Description

4 Shets-Sheet 1 Filed Dec. 27, 1955 INVEN'TOR. Robert R. Condor His Attorney R. R. CANDOR FORCED AIR COOL-ED REFRIGERATOR Dec 30, 1958 4 Sheets-Sheet 2 Filed Dec. 27, 1955 INVENTOR. Rob an R. Candor H/s Afforney Dc. 30, 1958 R. R. CANDOR 2,866,323

FORCED AIR COOLED REFRIGERATOR Filed Dec. 27, 1955 4 Sheets-Sheet 3 Fig. 3

INVENTOR. g. 4, Robert R. Condor H/s Attorney nited States FoRcEr) AIR COOLED REFRIGERATOR Application December 27, 1955, Serial No. 555,334 9 Claims. (Cl.;62-:187)

This invention relates to refrigerating apparatus and more particularly to a refrigerator inwhichno'frost'is deposited in'either the freezer or the warmer compartment.

An object of this invention is to provide a refrigerator having a first box or compartment tojbe maintained at a temperature below 32 F. and which is surrounded by an evaporator, said refrigerator also having a second box or compartment to be maintained at a refrigerating temperature above 32 F. and to which air is circulated from the evaporator to it in a manner to maintain it at a refrigerating temperature above32 F.

Further objects and advantages of the present invention will be apparent from the following description ref erence being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown. I

In the drawings:

Figure 1 is a vertical cross section of the refrigerator.

Figure 2 is a vertical cross section taken along the line 2-2 of Figure 1.

Figure 3 is a diagrammatic representation of the ren frigerating apparatus to be applied to the refrigerator shown in Figures '1, 2 and 5.

Figure 4 is a wiring diagram for the control of the refrigerating system shown in Figures 1 and 2, and, with modification, the refrigerating system shown in Figure 5.

Figure 5 is a vertical cross-section, somewhat similar to Figure 2, showing a modification of the invention.

The refrigerator, according to this invention, may comprise a first box or compartment'w 'to be maintained at a temperature below 32 F. A second box orcompartment 21 is to be maintained at a refrigerating temperature above 32 P. such as between 33 F. and 40 F. or 50 F. A first air passageway means 22 surrounds a'major portion of the box and has a first air inlet orinlets 23 into, and a first air outlet or outlet '24 from thebox 20. Either the inlet or the outlet may comprise a plurality of inlets or outlets, as desired. Arefrigerant evaporator 25, to be maintained below 32 F., is in thermal exchange with the first air passageway means 22. A second air passageway means 27 surrounds said evaporator and is in thermal exchange therewith and has a second air inlet orinlets 28 into, and a second air outlet oroutlets 29 from saidsecond box 21. Afirst blower 30 circulates air through and between saidbox 20 and said air passageway means 22. Asecond blower 31 circulates air through and between saidbox 21 and said second air passageway means 27.

Thermostatic means 35 controls the operation of saidsecond blower 31 in response to the temperature in the saidbox 21 to maintain its temperature at a refrigerating temperature of above 32 F. Such thermostatic means may take the form of athermostatic bulb 36 located inthebox 21 and connected to abellows 37 which moves theswitch blade 38 against thecompression spring 39 to open the switch when the temperature in the compartment orbox 21 falls below the selected temperature and to close the switch when such temperature rises above 52 placed at any accessible place for the user. the 'knob 52 may 'open themaster switch 53 which opens 2 the selected temperature, this-opening and closing of the switch being within predetermined limits.

The thermostatic switch may be adjustable .by means of a cam 40 which adjusts the otherwisestationary contact blade 41 up or down to adjust the temperature at which the Switchblade 38 opens and closes. The cam 40 may be adjusted by means of aknob 42 locatedat any place which maybe accessible to the user.

Theblower 31 is started'and stopped by-theswitch 38 in response to the temperature in compartment or box '21, the blower operating whenever the temperature .is above the selected temperature and stopping when the temperature in the box i below the selected temperature.

Theevaporator 25 may be part of any usual refrigerating system such as that shown diagrammatically .in Figure 3. Amotor compressor 40a discharges refrigerant intocondenser 41a which discharges liquid refrigerant through theline 42a and through the expansion valve orcapillary tube 43 into theevaporator 25. From there the evaporated refrigerant returns through theline 44 to themotor'compressor 40a.

Means are provided to maintain the temperature in theevaporator 25 at a low temperature below 32 F. Such means may take the form of athermostatic switch 45 which is actuated by a'bellowsi connected to a thermostatic-bulb 47 in thermal exchange with theevaporator 25. Theswitch 45 is open when'the temperature in the fevaporatorfalls below a predetermined selected temperature and closes when the refrigerant temperature rises above such selected temperature. Theswitch 45 may be made adjustable by means of the cam 50 which moves the stationary adjustable blade 51 up or down to vary and select the temperature at which theswitch 45 opens and closes. The cam 5% may be adjusted by the knob If desired,

and closes the entire electric system which is connected to the refrigerator. The lines L and L1 may be connected to the usual connector plug which is provided for a domestic refrigerator.

Themotor compressor 40a may be provided with the usual starter switch andprotector 40b, and the starting winding 49c and running winding 40d.

Theevaporator 25 may be defrosted by mean of hot gas or the like. Forexample, a by-pass line 54 may be provided with asolenoid valve 55 which is energized and opened during the defrost cycle and allows hot gas to be fed to theevaporator 25. Anelectric heater 56 may be placed against the refrigerating system, for example, at

the return line44, to add heat to the refrigerating system while the defrosting operation is being performed. The heater'Srs is energized during the defrost cycle at the same time that thesolenoid valve 55 is energized and opened.

Means for draining the defrost water may be provided. This :may take the form of adrain pipe 60 connected in such a position as to receive all of the water formed by the defrost operation. If desired, it may lead tosolenoid valve 61 which is energized and opened during the defrost period and is closed during the refrigeration cycle. The defrost water is discharged through the spout'el into thepan 63 which is placed over the-condenser 41 and from which the Water is evaporated during subsequent refrigeration cycles.

'The passageway orpassageways 27 may be formed by a spiral 'wall'7tl-and the passageway orpassageways 22 may be formed by a similarspiral wall 71.

.T he walls of theopenings 28 and 29 may be extended slightly above as indicated at 72 to prevent the flow of .defrost 'water through the openings during the -defrosting period.

:Thecompartment 20 maybe provided "with adoor 75 while thecompartment 21 maybe provided with-adoor 76. Thedoor 75 may be provided with adoor switch 76 which is adapted to be opened when the door is also opened and this deenergizes themotor 77 which drives the blower.30 whenever the door is opened.

A timer may be. provided which includes amotor timer 80 driving theearns 81 and 82 which haverefrigeration surfaces 84 anddefrost notches 85. The earns 81 and 82 actuate respectively theblades 90 and 91. During the refrigeration cycle theblade 90 energizes theblower motors 77 and 93 unless such motors are deenergized by the other switches which are in series therewith. During the defrost cycle theblade 91 energizes theheater 56,hot gas solenoid 55, and thewater drain 61. The motor compressor 40 is driven at all times except when it is deenergized either by theswitch 53 or theswitch 45. Theswitch 53 is open only when themanual control 52 is turned to the off position, and theswitch 45 is opened and closed in response to evaporator temperatures to maintain the evaporator at a preselected low temperature sufficient to keep thecompartment 20 at the desired below freezing temperature.

In more detail, the compartment orbox 20 may have afirst casing 100 surrounding. a major portion of saidcompartment 20. Casing 101 surrounds thefirst casing 100 and forms therewith thecircuitous air passageway 22 around thefirst casing 100 and between such casing'100 and thesecond casing 101. Aliner 102 surrounds thesecond casing 101 and forms therewith thecircuitous passageways 27. Thecasing 100 has theopenings 23 and 24 previously described, while thecasing 102, in combination with theliner 103 has theopenings 28 and 29.

The walls of theopenings 28 and 29 may be extended slightly above as indicated at 72 to prevent the flow of defrost Water through the openings during the defrosting period. All of the frost is deposited onevaporator 25 orcasing 101, outside of thecompartments 20 and 21.

In the modification shown in Figure the refrigerating system is substantially the same as the previous figures and the wiring diagram shown in Figure 4 is applicable to Figure 5 with the exception that all of the elements controlled by theline 105 in Figure 4 are omitted when the wiring diagram is applied to Figure 5. Preferably the evaporator 25a of Figure 5 is made of the open tube type, which permits air to flow between the tubes as well as around them, instead of the sheet metal type shown with respect to Figures 1 and 2 and Figure 3. The box or compartment of Figure 5 is surrounded by afirst casing 110. Thecasing 110 is surrounded, in turn, by a second casing 111 which forms I between them anair passageway 112. The evaporator a is enclosed within thepassage 112 and permits the air to flow freely around the entire passageway. If desired suitable bathing means, not shown, may be provided to insure a complete circuitous flow of air throughout thispassageway 112. Thecasing 110 has anopening 24 preferably near the front ofcompartment 20 for the blower andmotor 77 through which air is forced from thepassageway 112 into thecompartment 20. Thecasing 110 also has a series ofopenings 125 preferably at the rear ofcompartment 20 which permit the air to flow from thecompartment 20 back into thepassageway 112. With this construction the air which is to chill thecompartment 20 flows out through theopenings 125 into thepassageway 112 where the air circulates around and in contact with theevaporator 25a and has its temperature reduced to its lowest temperature, considerably below the temperature to be maintained incompartment 20. Thereafter this air is forced by thefan 30 back into thecompartment 20 as indicated by thearrows 126. The air incompartment 20 has its temperature raised a slight amount due to the heat received from themotor 77 as well as from the door corresponding to 75 of Figure 1. In this manner the air entering and circulating .tlirough thecompartment 20 has its. temperature raised slightly and its relative humidity reduced sufficiently to insure proper sublimation of all of the frost which might have found its way intocompartment 20. All of the frost deposits on theevaporator 25a, outside ofcompartments 20 and 21. Should any frost be introduced into said compartments it is quickly sublimated and transferred toevaporator 25a.

A second air passageway means 128 is formed around the box orcompartment 21 by means of theconcentric casings 129 and 130. If desired adivider wall 131 may be provided in thepassageway 128 which is open at any desired place in such a manner as to insure proper circulation of air all around thebox 21, so as to cool the entire outer surface thereof. Thepassageway 128 has a conduit 132 connecting thepassageway 128 with the interior of the box orcompartment 20. Thepassageway 128 has asecond conduit 133 connected to theair passageway 112. The construction is such that the air fromcompartment 20, which is at a slightly higher pressure, is forced through the conduit 132 into thepassageway 128 where the air circulates all around the outer wall of thecompartment 21 and then flows through theconduit 133 into thepassageway 112, where the pressure is slightly less than inside thebox 20 due to the action of thefan 30. A thermostatic bulb operates abellows 141 which in turn operates thedamper 142 to regulate the flow of air around thepassageway 128 to maintain the temperature of compartment 121 at the desired temperature above 32 F.

Means to control the relative humidity incompartment 21 of Figure 5 may be provided. This relative humidity regulator may take the form of manuallyadjustable dampers 145 and 146 which may be operated by the user to regulate the size of thebleed openings 147 v and 148 to regulate the flow of a small amount of air from thepassageway 128 through the interior ofcompartment 21. Thedamper 145 is adjacent a higher air pressure location inpassageway 128 than the air pressureadjacent damper 146. This pressure differential produces the air bleed throughcompartment 21. This bled air is of low relative humidity when it is warmed by the contents of thecompartment 21, and hence tends to reduce the relative humidity incompartment 21 as the amount of air bled is increased and vice versa. By this means, the user may regulate any relative humidity desired within the limits of the apparatus.

In all of the modifications proper insulation, as indicated at 150, may be placed within the refrigerator. Thecompartments 20 and 21 of Figure 5 may be provided with doors similar to 75 and 76 of Figure l, and the transverse cross section of Figure 5 may be substantially as indicated in Figure l, modified only so far as the construction is shown to be different in Figure 5.

In the operation of the embodiment shown in Figures 1 through 4, the refrigerating system operates substantially constantly except that the compressor 40 is started and stopped under the control ofthermostatic bulb 47 which maintains the refrigerant inevaporator 25 at a temperature below 32 F. sufiiciently low to maintain thecompartment 20 at the desired freezing temperature below 32 F. Theblower 30 circulates air between thecompartment 20 and theevaporator 25 constantly during the refrigeration cycle to provide the necessary transfer of heat to theevaporator 25. The air, as it passes in contact with theevaporator 25, is chilled to its lowest temperature and thereafter enters thecompartment 20 through theopenings 23. This air is then slightly warmed by the heat passing through thedoor 75 and thus has its relative humidity slightly decreased. Hence it sublimates any frost which may be present incompartment 20. Thereafter the air is repeatedly returned to be circulated in contact with theevaporator 25. At the same time, air from thecompartment 21 is forced by the fan orblower 31 into thepassageways 27 where it is chilled by thermal exchange through assesses the casing-1'01Wi ththe evaporator 25 and "this air then returns into compartment "21 through theopenings 28. When thecompartment 21 hasbeen chilled 'below the preselected temperature, thethermostatic bulb 36 opens the switch and stops theham blower 31 until such time as the temperature in compartmentzl rises above the selected temperature. "Thereafter the switch '38 -is closed and theblower 31 is again operated, this cycling continuing in a manner'to maintain'th'e temperature of thecompartment 21 at the preselected refrigerating temperature above 32F.

During the defrost'cycle the compressor 4011 continues to operate, but the blowers 3t] and 31 are deenergized and the heater-56 is energized while the valves '55 and 61 are opened. This causes thetemperatureofthe evaporator 25 to be raised sufiiciently to defrost all of the frost which may have accumulated on theevaporator 25 or on thewall 101. The Water thus formed flows down thepipe 60 and through the solenoid valve '61 andfaucet 62intothe drain pan 63, where the water is evaporated by heat fromcondenser 41 and subsequent refrigeration cycles. The relative sizes of the refrigeration surfaces 84 andthe defrostnotches 85 are selected to provide desired refrigeration cycle length of time as compared with the defrost length of time.

The operation of the modification shown "inFigure 5 is the same insofar as the refrigeration system is concerned. Air is forcedby the blower '30 in heat exchange relationship with the evaporator 2511, the air leaving thecompartment 20 through theopenings 125 into the passageway 112where the air is chilled to its lowest temperature and has its moisture content reduced to the minimum. Thereafter the air enters the compartment 26 through theopening 24, where the air is "slightly heated "by heat from themotor 77 as well as from the heat leaking through thedoor 75 corresponding to the one in Figure 1. This rise in the temperature of the air incompartment 20 insures the sublimation of any frost which maybe present incompartment 20 and prevents the deposit of any frost therein, as will be obvious. 'At the same time, air is forced through the conduit 132 by theslightly'higher air pressure incompartment 20 and through thepassageway 128 completely surrounding the box orcompartment 21 and thus chills the surroundingwall 129 of thebox 21 to maintain the temperature incompartment 21 at the desired refrigeration temperature above 32 F. The air from passageway 128returns through theconduit 133 into the passageway "112 because of the slightly lower pressure within passageway 1.12 caused by the operation of the blower The amount of air circulated through thepassageway 128 is regulated by thethermostatic bulb 140 operating thedamper 142 to regulate theamount sufficiently to obtain the desired refrigerating temperature above 32 F. incompartment 21. The relative humidity of'the air in compartmentZl is regulated by the opening and closing of thedampers 145 and 146 to regulate the amount of air bled from thepassageway 128 through the interior ofcompartment 21.

The boxes or casings .100 and/or 110.may be made of relatively heat insulating material to prevent melting of the frozen food incompartments 20 during the defrosting operation. This .also increases the temperature of the airi'n compartmentsltlin comparison 'tothe temperature of the air inpassageways 22 and/or 112 during the refrigerating cycle, and reduces the relative humidity in saidcompartments 20, thus increasing the frost sublimating effect.

While the forms of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted as may come withln the scope of the claims which follow.

What is claimed is as follows:

1. In combination: a refrigerator having first means forming a first compartment to be maintained at a tern perature below 32 and second-means forming asec- 0nd compartment to be -maintained at a refrigerating temperature above 32 'F.; said first means including a 'first'casing surrounding a major portion of said first compartment and having an air inlet into and an air outlet from said first compartment; said second means including a second casing surrounding said first casing and forming first circuitous air passageways around said first casing and between said first and second casings connected to said airinlet andair outlet; a liner surrounding said second casing and forming second circuitous air passageways around said second casing and between said second casing and said liner and having an inlet from an air outlet into said second compartment; and refrigeran evaporator means to be maintained below 32 F. in thermal exchange with said second casing.

2.In combination: a refrigerator having'first means forming-a first compartmentto be maintained at a temperature below 32 'F.;and secondmeans forming a second compartment to be maintained at a refrigerating temperature above 32 =-F., said first means including a first casing surrounding a'majorportion of said first compartment and having an'air inlet-into and an air outlet from said first compartment; said second means including a second casing surrounding said first casing and forming first circuitous air passageways around said first casing and between said first and second casings connected to said air inlet and air outlet; a liner surrounding said second casing and forming second circuitous air passageways around said second casing and between said second casing and said liners and'having-an inlet from and air outlet into said second compartment; a first blower for circulating air through said first circuitous air passageways; a second blower for circulating air through said second circuitous air passageways; and refrigerant evaporator means to be maintained-below 32 F. in thermal exchange with said second casing.

3. In combination: a refrigerator having first means forming a first'compartment to be maintained at a temperature below 32 F. and second means forming a second compartment to be maintained at a refrigerating temperature above 32 F., said first means including a first casing surrounding a major portion of said first compartment and having an air inlet into and an air outlet fromsaid firstcompartment; said second means including a second casing surrounding said first casing and forming firstcircuitous air passageways around said first casing and between said first and second casings connected to said air inlet'an'd air outlet, a liner surrounding said second casing and forming second circuitous air passageways around said second casing and between said second casing and said liner andhaving an inlet from and an air outlet into'said'second compartment; a blower for circulating air through said second air passageway,

thermostatic means for'controlling-the operation of said blower in response to second compartment temperature; and refrigerantevaporatormeans to be'maintained below 32 F. in thermal exchange with said second casing.

4. In combination: a refrigerator having first means forming a first 'compartment to be maintained at a term perature below 32 and second means forming a second compartment'to be maintain'ed at a refrigerating temperature :above 32 :F., said first means including a first casing surrounding a major'portion of said first cornpartment and having an air inlet into and an air outlet from said first compartment; said second means including a second casing surrounding said first casing and forming a first circuitous air passageway around said first casing and between said first and second casing connected to said air inlet and air outlet; a blower for circulating air through said passageway and said air inlet and air outlet; refrigerant evaporator means to be maintained below 32 F. in thermal exchange with said air passageway; a double liner surrounding a major portion of said second compartment and forming a second circuitous air passageway inside said double liner in thermal exchange with said second compartment; a first conduit connecting said first compartment and said second circuitous air passageway; and a second conduit connecting said second circuitous air passageway and said first circuitous air passageway; and thermostatic means controlling the flow of air through said conduits in response to the temperature in said second compartment to maintain it at a refrigerating temperature above 32 F.

5. In combination: a refrigerator having first means forming a first compartment to be maintained at a temperature below 32 F. and second means forming a second compartment to be maintained at a refrigerating temperature above 32 F., said first means including a first casing surrounding a major portion of said first compartment and having an air inlet into and an air outlet from said first compartment; said second means including a second casing surrounding said first casing and forming first circuitous air passageways around said first casing and between said first and second casings connected to said air inlet and an air outlet; a liner surrounding said second casing and forming second circuitous air passageways around said second casing and between said second casing and said liner and having an inlet from and an air outlet into said second compartment; refrigerant evaporator means to be maintained below 32 F. in thermal exchange with said second casing; means to defrost said evaporator means periodically; and a water drain to receive and convey away water produced during the defrosting of said evaporator means.

6. In combination: a refrigerator having first means forming a first compartment to be maintained at a temperature below 32 F. and second means forming a second compartment to be maintained at a refrigerating temperature above 32 F.; said first means including a first casing surrounding a major portion of said first compartment and having an air inlet into and an air outlet from said first compartment; said second means including a second casing surrounding said first casing and forming a first circuitous air passageway around said first casing and between said first and second casing connected to said air inlet and air outlet; a blower for circulating air through said passageway and said air inlet and air outlet; refrigerant evaporator means to be maintained below 32 F. in thermal exchange with said air passageway; a double liner surrounding a major portion of said second compartment and forming a second circuitous air passageway inside said double liner in thermal exchange with said second compartment; a first conduit connecting said first compartment and said second circuitous air passageway; and a second conduit connecting said second circuitous air passageway and said first circuitous air passageway; thermostatic means controlling the flow of air through said conduits in response to the temperature in said second compartment to maintain it at a refrigerat ing temperature above 32 F.; means to defrost said evaporator means periodically; and a water drain to receive and convey away waterproduced during the defrosting of said evaporator means.

7. In a refrigerator: a first box forming a first com-- partment to be maintained at a temperature below 32 F.; a second box forming a second compartment to be maintained at a refrigerating temperature above 32?. F.; means forming first air passageway means surrounding a major portion of said first box and having a first air inlet into and a first air outlet from said first box; a refrigerant evaporator to be maintained below 32 F. in thermal exchange with said first air passageway means; means forming a second air passageway means surroundmg said evaporator and in thermal exchange therewith and having a second air inlet into and a second named temperature at a refrigerating temperature above 8. In a refrigerator: a first box forming a first compartment to be maintained at a temperature below 32 F.; a second box forming a second compartment to be maintained at a refrigerating temperature above 32 F.;

means forming first air passageway means surrounding a major portion of said first box and having a first air inlet into and a first air outlet from said first box; a refrigerant evaporator to be maintained below 32 F. in thermal exchange with said first air passageway means; means forming a second air passageway means surrounding said evaporator and in thermal exchange therewith and having a second air inlet and a second air outlet from said second box; a first blower circulating air through and between said first box and said first air passageway means; a second blower circulating air through and between said second box and said second air passageway means; means to defrost said evaporator periodically; and a water drain to receive and convey away water produced during the defrosting of said evaporator.

9. In a refrigerator: a first box forming a first compartment to be maintained at a temperature below 32 F.; a second box forming a second compartment to be maintained at a refrigerating temperature above 32 F.; means forming first air passageway means surrounding a major portion of said first box and having a first air inlet into and a first air outlet from said first box; a refrigerant evaporator to be maintained below 32 F. in thermal exchange with said first air passageway means; means forming a second air passageway means surrounding said evaporator and in thermal exchange therewith and having a second air inlet into and a second air outlet from said second box; a first blower circulating air through and between said first box and said first air passageway means; a second blower circulating air through and between said second box and said second air passageway means; thermostatic means controlling the operation of said second blower in response to the temperature in said second box to maintain said last named temperature at a refrigerating temperature above 32 F.; means to defrost said evaporator periodically; and a water drain to receive and convey away water produced during the defrosting of said evaporator.

References Cited in the file of this patent UNITED STATES PATENTS Strang et al. Sept. 20, 1949

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