US2056165A - Refrigerator - Google Patents

Description

L,LBRONAUGHETAL REFRIGERATOR Filed Feb. 16, 1931 /7 7- TUR/v5 5/ POTT f -R //\//5/\/ TERE L. J. BRONAUGH latented Oct. 6, 1936 Urraof srarss PA CE land, Oreg.; said Bronaugh assignor Potter tosaid Application February 16, 1931, Serial No. 516,032

2l Claims. icl. 62-116) cally defrosted is unsuitable for the preservation This invention relates generally to the art of refrigeration, and particularly to a. new form' of refrigerator.

The main object of this invention is the design 5 of a refrigerator which will make it possible at 'one and the Sametime and over long or short periods of time to perform several highly desirable tasks, namely to form ice or freeze desserts quickly, to provide cold storage for frozenmeat and foo'd stuffs, and to provide storage for food at y temperatures above freezing.

.'I'he second object is to construct a cabinet in which the ice-making or freezing unit is thermally insulated from the food storage department.

.l5 The third object is the constructionof a refrigerator which is not a compromise'between a quick freezing refrigerator and one whichis ideal for food storing, but which will possess both of these properties in maximum quantities.

The fourth object is to provide a refrigerator having its heat pumping action' controllable by food compartment temperatures and in which the eiilciency of the freezing unit will be increased as the rate of heat pumping from the food department increases. i The vfth object is to secure the utmost sim-A all defrosting and objectionable drying out of the foods.

The eighth object is to make it possible for the 40 householder tov utilize all of the advantages obtainable from varying degrees of refrigeration heretofore only possible in large commercial plants. Before entering into a description of this invention it must be understood that while mechanical refrigeration has many advantages over the ice box used by our ancestors, it has many limitations which are greatly magnified in the smaller sizesI of refrigerating units, especially of the type used in the home. These limitations and requirements have been increased rather than decreased by the advent of the use of frozen food stuffs,

which render it imperative that the frozen food remains frozen until it is prepared for use.

Obviously, a refrigerator which must be periodiof this class of food. t

Again, there are, generally speaking, two classes of food which are put into a refrigerator; rst, food requiring merely to be kept cool-that is, above freezing, and in most cases having a relatively high rate of evaporation.` Second, food having a relatively low rate of evaporation and which should be maintained at temperatures Well below freezing. In addition to this, comes the l0 ever increasing demand for the ability to form ice Aand freeze desserts quickly.

It follows that the designer of a refrigerating machine soon finds himself compromising be@ tween a quick freezing machine and one which is l5 best adapted for the storage of food. If the temperature of the food storage compartment falls too low as the result of an attempt to provide quick freezing' the consequence is a rapid drying out of the'food. To offset this certain manu,- 2a,v

facturers providea cover for the food to prevent its drying out and impose'upon the user the necessity of frequentlyvadjusting the controls to obtain f the kind of refrigeration desired. It is easily seen that an adjustment of controls to suit varying 25 conditions (several of which may exist at the same time) does not 'solve the problem. Inthe refrigerator about to be described no adjustment of controls is necessary.-

These, and other objects, will become more ap- 30 parent from the specification following as illustrated in the accompanying drawing, in which:

Fig. l is a'vertical section taken along the line 'i-i in Fig. 2.

Fig. 2 is a vertical section taken along the line 35 2-2 in Fig. l; I l Fig. 3 is a perspective view of the cabinet.

Fig. 4 is a sectionl taken along the line t--t in Fig-2.

Similar lnumbers of reference refer to similar 40 parts throughout the several views. p f

Referring in detail to the drawing, there is shown a cabinet having four separate and distinct com partments contained withinan outer casing Iii. These' consist of a pump room il a freezing com- 45 partment I2, a cold storage compartment i3 and a food storage compartment it. The pump room li contains any desirable form of heat pumping unit which, in this instance, includes a compressor l5 which is belt driven by a motor it. There is 50 also provided the usual receiver il and condenser te. .i i

The freezing compartment it is preferably a brine tank and includes suitable freezing trays i9. Adjacent to the freezing compartment i2 is ac'old 35 Gil one or more shelves 20. Heat is permitted to flow freely from the cold storage compartment I3 throughthe wall 2l to the freezing compartment I2, butthe compartments I2 and I3 may not draw heat from any other portion oi' the refrigerator. The freezing compartment or brine tank, contains an expansion coil 22 which will be referred to as a freezing coil, and which is provided with the expansion valve 23. The coil 22 draws refrigerant from the receiver I1 through the high pressure refrigerant line 24. The food storage compartment I4 is provided with a cooling coil 25 which draws refrigerant from the discharge of the freezing coil 22 and returns same through the pipe 26 to the compressor I5. l

The compartment I4 may have any number of divisions and shelves 21 and contains a drip collecting shelf 28 by means of which condensed moisture from the cooling coil 25 is collected and drained through an outlet.29, either into a container 30 (as shown) or into a waste pipe. The food storage compartment I4 contains a temperature-actuated motor controlling switch 3l which is placed in the motor circuit 32 and is set to operate the compressor I5 whenever the temperature of the food storage compartment rises above the desired temperature, which, in this case, will be assumed to be forty degrees. The expansion valve 23 is set to permit av flow of refrigerant into the freezing coil 22, which will provide a temperature approximating zero, while the temperature in the cold storage compartment I3 will be in the neighborhood of twenty degrees. y

'Ihese relative values are of course dependent upon the various controlling factors and are given only Ito permit a clearer understanding of the in- `vention and the objects attained thereby. Any suitable insulating material 33 is employed in the construction of the cabinet, and the compartment I4, and combined'compartments I2 and I3 are provided with doors 34 and 35 packed with insulation material.

The requisite 'difference of temperature between thecooling compartment I4 and the cold storage compartment I3, can be maintained with the greatest economic efficiency -by not only providing a proper ratio 'of the cooling elements for said compartments, but also by providing a proper relation of the insulation of theA two compartments. It will be understood that there is no such thing as a perfect heat insulator and that a certain amount of heat is always flowing into a refrigerator compartment frcmthe surrounding atmosphere (provided, of course, that the surrounding atmosphere is Warmer vthan that of the refrigerator compartment). A heat insulator may thus be more properly termed a heat iinpedance because all it does is to retard the ow of heat and the rate of heat flow through a heat insulator of given quality and thickness depends upon the temperature head. Since very low temperatures are to be maintained in compartments I2 and I3 it is important that they be thoroughly heat insulated. In other words, theheavier the insulation the better and the only limitation to the eiiiciency of such insulation is that imposed by questions of bulk, and expense. As shown in the drawing, compartmentsY I2 and I3 are 'separated from the outside atmosphere by thick rear and side walls 38 and also by a thick door 35 so that the heat flow into said compartments is reduced to a minimum. Since the chamber I I under the compartments I2 and I3 contains the apparatus for pumping heat out of the refrigerator, this compartment would naturally be warmer than the outside atmosphere and consequently a wall 33 is provided which is even thick'er than the walls 38 to insulate the chambers against heat pumped into and generated in the compartment I I. The temperature drop between the cooling compartment I4 and compartments I2 and I3 is comparatively much smaller and hence a thinner wall 40 furnishes sumcient resistance to heat flow into compartments I2'and I3 out of compartment I4. The walls 4I and door 34 separating the cooling compartment I4 from the outside atmosphere are thinner than the walls 38 and door 35, as shown. This difference of wall thickness is provided not as a measure of economy but because it is desired to maintain a higher temperature in compartment I4 than in compartments I2 and I3 by permitting a greater heat flow into compartment I4.

As indicated above it makes no difference how low the temperature falls in chambers I2 and I3, but the range of temperatures permissible in compartment I4 is more critical. Foods kept in compartment I4 must lnot be frozen and the moisture saturation point of the air in compartment I4 should not be lowered to such an extent as to dry out the foods; hence it is important to hold the temperature in said compartment well above the freezing point and yet low enough to prevent the food therein from spoiling. We have found that a temperature of about 40 Fahrenheit is very satisfactory under most conditions; but some other normal temperature may be selected provided it is above the freezing point. Whatever the temperature selected, it is obvious that it should be maintained without any great degree of variation and'for this reason the control of the heat pumping system is preferably made to depend upon the temperature in the chamber I4 and the thermostat3l is placed in chamber I4 rather than either of the other chambers. If the insulation of chamber I4 were as heavy as that of the other chambers the temperature in the compartment I4 might remain for a long period unvaried and in the meantime the temperature might be raised considerably in chambers I3 and I2, by opening the door 35 or by introducing warm foods therein. without in the least affecting the thermostat 3l and hence without operating the heat pumping unit. Thus the temperature ratio between the several compartments would be disturbed and could not be restored until the heat .pumping unit was restarted. Since, however, the insulation separating chamber I4 from the outside atmosphere is so proportioned that the rate oi ambient heat flow into chamber I4 is greater than into cham-V bers I2 and I3, the intervals between operations of the heat pumping unit is reduced and thus more frequently are the relative temperatures o! the several chambersreestablished. It will be understood, of course, that because of the series connection of the cooling elements the heat will be pumped out of compartments I2 and I3 through the cooling element 25 so that said compartments must be reduced to the desired temperature before the compartment I4 will be chilled sufliciently for the thermostat 3I to stop the operationof the heat pumping plant.

While the thermostat 3l controls the temperature of the compartment I4 the setting of the expansion valve 23 controls the temperature of compartments I2 and I3. `As the expansion Y mated' entireltr.v but alsothe.

therein, will cool compartment I 4. Thus, by our system the compartments I2 and I3 must first be cooled tominima fixed by the setting of the expansion valve beforecompartment I6 can be lcooled to a minimum set by the thermostat. This arrangement whereby onetemperature iscontrolled by a thermostat and anotherby an expension valve is a novel feature of ourinvention. By proportioning the insulation to offer greater resistance to inflow of heat into the cooling com `pertinent; I4 than into the cold storage compartment I3, a more uniform temperature can be obtained in the latter compartment. Were the insulation of theA two chambers ofthe same heatresistant quality and thickness, the rate of inflow into the cold storage compartmentwould be greater, by. reason of the greater temperature drop between the outside .atmosphere and the cold storage compartment than between the outside atmosphere and the cooling compartment. The heat pumping unit, after pulling down the temperatures of the two compartments to their re-I spective predeterminedheat levels would then be stopped by actuation of thethermostat in tlie cooling chamber. Thereafter, the temperature .in the cold storage chamber would climb faster than that inthe cooling chamberbecause of the greater head of ambient heat impressed on the insulationv of the cold storage chamber. Hence. there would be a markedrise in temperature in the freezing compartment before the temperature in the cooling compartment would rise sufficiently to actuate the thermostat. This difculty wc` have overcome byproportioning the heat impedance of the walls tothe heat head they must oppose and while suchproportioning results in# cidentally in economy of material, it has for its primary object to maintain a more uniform tem perature in the cold storage compartment as well as in the freezing compartment whichis thery mally connected therewith.

` From the foregomgtlt win be seein that there is provided .a refrigerator having a non-frosting food storage compartment in which food may beheld atv desirable' temperatures withoutundue evaporation. Secondly, that quick freezing for ice and desserts is ever available. Thirdly. that there is provided' uninterrupted cold storagev at freezing temperatures, and'lastly, that the necessity for regulating the controlfsystem is en tirely eliminated since awide range of temperatures is provided simultaneously, and further..

that lnot only is the necessity for defrostinglelim- V v vaporation-"of" the food stuusis redueecto a minimum; j

'I'hearticles placed inthe cold lstorage compartment are those not givingfon much moisture,-

cold storage compartment, yeither byrevaporation or by' opening the door thereof. will be deposited ,i as snow rather.. thanas ice.V due tothe low temperature prevailing .in 'the compartment I3. In

other'worfds, there is noobjectionable f'ros'ting'inV the' cold storage compartment. for -thereason above stated, and no frosting coolingcomf-I and whatever moisture does find its way into the the freezing point.

is above freezing.- lThere may, of course, occur a slight amount. of frosting where the coolingv coil 25 enters the compartment I4.

Another factor of great value found in this arrangement resides in the fact that the more the cooling compartment is used the greater will be the efficiency of the cold storage and freezing compartments. t

By arranging the compartments as illustrated with the cooling chamber I4 which isthe one partme'nt since the temperature maintained there most used, at the top of the cabinet, access may' l be had to this compartment without stooping, while-the intermediate compartments I2 and I3 are also elevated by placing them above the compartment II, so that the various food chambers are arranged to provide maximum convenience in actual service.

We claim:

1. A refrigerator consisting of a cabinet having formed therein a cooling compartment, a combined freezing and cold storage compartment thermally connected lto each other butl insulated from said cooling compartment, means for pumping heat from all of said compartments through saidcooling compartment, and means for controlling the heat pumping action actuated by the temperature of said cooling compartment.

2. A self-contained refrigerator comprising a' cabinet having a cooling compartment and a cold storage compartment below vthe cooling compartment and thermally insulated therefrom and having also a freezing compartment also thermally insulated from the cooling compartment but .thermally connected to the cold storage compartment and a pump compartmentbelow and thermally insulated from thecold storage and freezing compartments, an'expansion line including in series a coil in the freezing compartment and a coil "in the cooling compartment, said coils being proportioned to maintain a temperature above-freezing in the cooling compartment and a materially lower, temperaturel in the freezing compartment,

a single expansion valve in the line-at the point of entrance the f into the freezing compartment', a heat pumping unit in the pump compartment for circulating refrigerant through said 3. A household refrigerator comprising a cabinet formed with a freezing compartment, a cold storage compartment thermally connected thereline, and thermally actuated means in the cooling compartment for controlling the pumping unit.

with but separated therefrom by a continuous" partitlon, a cooling compartment thermally insulated from the freezing andv cold'storage compartments and insulatedv against loss of moisture thereinto, and means for maintaining the freezing and cold'storage compartments at a temperature well-below the freezing point and thecooling compartment at"` a predetermined temperature above v4. A refrigeratoncomprising a. cabinet formed i with twoI compartments and with heating insula-4 tionseparating saidv compartments from each other and from the voutside atmosphere, refriger ating means- .for abstracting heatfrom-.both of x the compartments. insulation of p the compartments being adapted to oder a higher resistanceto inflow of heat into one compartment than into the other,V and thermo-.sensitive'means in the" latten compartment for controlling said refriger' 5. -A'refrierawr eemprising afcabinet formenA withfa; cooling compartment and a cold storage compartment, thermally ment to a lower temperature than that of the cooling compartment, the thermal-insulation of the compartments being rso relatively proportioned as to offer a greater resistance to inow of heat into the freezing compartment than into the cooling compartment, and thermo-'sensitive means for controlling the refrigerating means, said thermo-sensitive means being located in the compartment into which there is the greater nor-` mal inow of heat.v

6. A refrigerator comprising a cabinet formed with a cooling compartment and a freezing compartment thermally insulated from each other and.from the outside atmosphere, refrigerating means for cooling the freezing compartment to a lower temperature than that of the cooling compartment and thermo-sensitive means in the latter compartment for controlling said refrigerating means, the thermal insulation of the compartments being so relatively proportioned as to admit a greater inflow of heat into the cooling compartment than into the freezing compartment.

7. A refrigerator comprising a cabinet formed with a cooling compartment and a freezing compartment, said compartments being thermally insulated from each other and from the outside atmosphere, means for pumping heat from the freezing compartment through the cooling compartment so as to lower the temperature of the former below that of the latter,.and a controller for said means responsive to temperature conditions in the cooling compartment, the thermal insulation of the two compartments being relatively so proportioned as to offer a greater resistance to inflow of heat into the freezing compartment than into the cooling compartment.

8. A refrigerator comprising a cabinet formed y with a 'cooling compartment and a freezing compartment and a power plant compartment, a heat vpumping unit in the latter compartment, an expansion line operatively connected with said unit.

and extending sequentially through the freezing and cooling compartments, a controller for said unit actuated by temperatures in the cooling compartment, the cabinet having outside walls of insulationmaterial and partition walls of insulation material between the compartments, the insulating quality of the walls beingyindividually Y proportioned to predetermined differences'of temperature on opposite sides thereof.

9. A refrigerator comprising a cabinet formed with a cooling compartment and a freezing compartment and a power plant compartment, a heat pumping unit in the latter compartment, an expansion line operatively connected with said unit and extending sequentially through the freezing and cooling compartments, `a controller for said unit actuated by temperatures in the'cooling coml partment. the cabinet having outside walls of insulation material and partition walls of insulation material between the compartments,'theinsulat ing quality of the walls being individually proportioned to predetermined differences of temperature on opposite. sides thereof. the cooling compartment being located above the freezing compartment and the power plant compartment below the Vfreezing compartment.

10. A refrigerator a cabinet formed i with a lcooling compartment and a freeling compartment.. said cots being insulated .from each other and from the outside atmosphere. hasi-expansion line passingthrough the freising and cooling compartments, said line including a freezing coil in the freezing compartment and a non-frosting coil inthe cooling compartment, an expansion valve in said line at its point of entrance into the freezing compartment, means for forcing refrigerant through said line, and a controller for said means actuated by temperatures in the cooling compartment, the thermal insulation of the compartments being relatively so proportioned as to admit a greater inflow of heat into the cooling compartment than into the freezing compartment.

11. A refrigerator comprising a cabinet formed with a cooling compartment and' a freezing compartment thermally insulated from each other and from the outside atmosphere, refrigerating means for cooling the freezing compartment to a lower temperature than that of the cooling compartment, and thermo-sensitive means in one of the compartments for controlling said refrigerating means, the thermal insulation of the compartments being so relatively proportioned as to admit a greater inflow of heat into the cooling compartment than into the freezing compartment.

12. A household refrigerator comprising a cabinet having at least two food chambers thermally insulated from each other and from the outside atmosphere, and a refrigerating system constructed and arranged to cool one of said chambers far below the freezing point of water and the other chamber above said freezing point, said system comprising an expander in each chamber and apparatus within the cabinet for circulating a volatile fluid through such expanders, said fluid constituting the sole refrigerant thus circulated, said system also including means constructed and arranged to maintain the external surface temperature of the expander in the warmer chamber above said freezing point.

13. A household refrigerator comprising a cabinet having at least two food chambers thermally insulated from each other and from the outside atmosphere, and a refrigerating system constructed and arranged to cool one of said chambers far below the freezing point of water and the other chamber above said freezing point, said system comprising an expander in each chamber and apparatus withinthe cabinet for circulating a volatile uid through such expanders,.said-iluld v constituting the sole refrigerant thus circulated,

above said freezing point, said 'means comprising I instrumentalities for maintaining `a wide temperature differential between the exterior and the interior of the expander in the warmer chamber.

, 14. A household refrigerator comprising a cabinet having at least two food chambers thermally insulated from each other and from the outside atmosphere, and a compressor-condenser-expander system constructed and arranged to cool one of said 4chambers far below the freezing peint of water and the other chamber above said freezing point, said system comprisinga chilling element in each chamber and apparatus within the cabinet for circulating a volatile uld vthrough the chilling elements, said uid constituting the sole refrigerant in said system, said system also including means constructed and arranged to maintain the external surface of the chilling element in the above said freezing point.

aand" a compressor-condensen-exis pander system constructed and arranged to cool one of said chambers far below the freezingpoint of water and the other chamber above said freezing point, said system comprising an expansion coil in each chamber and apparatus within the cabinet for circulating a volatile fluid through such coils, said fluid constituting the sole refrigerant in said system, said system alsoincluding means constructed and arranged to maintain thek external surface of the coil in the warmer chamber above said freezing point.

v16. A household refrigerator comprising a cabinet lhaving at least two food chambers thermally insulated from each other and from the outside atmosphere, and a compressor-condenser-expander system constructed and arranged to cool one of said chambers far below the freezing point of water and the other chamber above said freezing point, said system comprising apair of chilling elements connected in series with one of the elements in each chamber and apparatus within the cabinet for circulating a' volatile fluid through said elements, said fluid constituting the sole refrigerant in said system, said system also including means constructed and arranged to maintain the external surface of the chilling element in the warmer chamber above .said freezing point.

17. A household refrigerator comprising a cabinet having at least two food chambers thermally insulated from each other and from the outside atmosphere, and a refrigerating system constructed and arranged to cool one of said chambers far below the freezing point of water and the other chamber above said freezing point, said system comprising an expander in each chamber and apparatus within the cabinet for circulating a volatilefiuid through such expanders, said fluid constituting the sole refrigerant thus circulated, said system also including control means constructed and arranged to maintain the humidity in the warmer chamber at a'relative value of at least 100 per cent at 32 degrees Fahrenheit.

18. A household refrigerator comprising a cabinet vhaving at least two food chambers thermally insulated from each other and from the outside atmosphere, and a compressor-condenserexpander system constructed and arranged to cool one of said chambers far below the freezing pointof water and the other chamber above said freezing point, said system comprising a chilling element in each 'chamber and apparatus within the cabinet for circulating a volatile fluid through the chilling elements, said fluid constituting the sole refrigerant -in said system, said system also including means constructed and arranged to.

maintain the humidity in the warmer chamber at a relative value of at least 100 per cent at 32 degrees Fahrenheit.

19. A household refrigerator comprising a. cabinet having at least two food chambers thermally insulated from each other and from the outside atmosphere, and a compressor-condenser-expander system constructed and arranged to cool 'one of said chambers far below the freezing point sole refrigerant in said system, said system also including means constructed and arranged to maintain the external surface of lthe chilling element in the warmer chamber above said freezing point; said means comprising instrumentalities for maintaining a wide temperature differential between the exterior and the interior of the latter chilling element. Y

20. A household refrigerator comprising a cabinet having at least two food chambers thermally insulated from each other and from the outside atmosphere, and a compressor-condenser-expander system constructed and arranged to cool one of said chambers far below the freezing point of water and the other chamber above said freezing point, said system comprising an expansion coil in each chamber and apparatus within the cabinet for circulating a volatile fluid through such coils, said iiuid 'constituting the sole refrigerant circulated through the coils, saidssystem 4also including means constructed and arranged to maintain the external surface of the coil in the warmer chamber above said freezing point, said means comprising heat-absorbing fins formed on the latter coil.

21. A household refrigerator comprising a cabinet having two food chambers thermally in- 'sulated from each other and thel outside atmosphere, refrigerating means in the cabinet ther- .mally proportionedl to cool one of the chambers to asharp freezing temperature while cooling frigerating means whenever the surface temperature of the expander in the warmer chamber falls to a predetermined minimum above the freezing point of water and to restart the operation of the refrigerating means when said surface rises ,above a predetermined maximum.

LEWIS J. BRONAUGH. THOMAS 1.u POTTER.

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