US2416354A

US2416354A - Controlled humidity refrigerator

Info

Publication number: US2416354A
Application number: US528581A
Authority: US
Inventors: Malcolm G Shoemaker
Original assignee: Philco Ford Corp
Current assignee: Space Systems Loral LLC
Priority date: 1944-03-29
Filing date: 1944-03-29
Publication date: 1947-02-25
Anticipated expiration: 1964-02-25

Description

Feb. 25, 1947.

M. G. SHOEMAKER CONTROLLED HUMIDITY REFRIGERATOR 2 Sheets-Sheet Ll. F/QZ Filed March 29, 1944 F 25, 19475 M. e. SHOEMAKER v CONTROLLED HUMIDITY REFRIGERATOR '2 Sheets-Sheet 2 Filed March 29, 1944 Patented Feb. 25, 1947 CONTROLLED HUMIDITY REFRIGERATOR Malcolm G. Shoemaker, Abington, Pa., assignor, by mesne assignments, to Phllco Corporation,

Philadelphia, Pa, vania a corporation of Pennsyl- Application March 29, 1944. Serial No. 528,581

1 This invention relates to refrigeration apparatus, and is particularly concerned with re- 9 Claims. (Cl. 62-6) frigerators which include a high humidity compartment especially adapted 'to preserve foodstuffs without dehydration thereof. The invention has especial reference to such refrigerators, in which the compartment air is forcibly circulated in heat exchange relation with an evaporator.

More specifically, the present invention has reference to refrigerators of the multiple temperature type in which the temperature of the air in the main food storage compartment is maintained above that existing in other portions of the box, andthe relative humidity in said compartment is at a high value.

In such apparatus, it has proven difllcult to insure the desired degree of humidity throughout A further object of the invention resides in the provision of a refrigeration apparatus, in which circulating air provides heat'transfer capacity additional to that effected through the walls of the food storage compartment.

It is also an object of the invention to provide a refrigerator in which undesired moisture is removed from the cabinet air without causing the accumulation of frost in any portion of the refrigerating system.

Broadly, the present invention provides a refrigerator having a plurality of zones maintained at moist-cold," sharp-freeze and intermediate temperatures respectively, in accordance with the requirements of various foodstuffs to be preserved therein; while a more specific object of the inall seasons of the year, while preventing the humidity from reaching undesirably high values at certain times, and particularly in damp climates. Proper humidity control is-particularly important, in view of the fact that cooling of the "moist-cold compartment is customarily accomplished by effecting the necessary heat transfer through the walls of said compartment. method of heat transfer has certain evident ad vantages, such for example, as affording a food compartment which is clear and unobstructed, but these advantages need not be considered in detail here. Efiecting the cooling in the above mentioned manner results in maintenance of the temperature of the compartment walls at a value well below the dew point temperature of the air in said compartment at the high relative humidity customarily existing in the latter. As a consequence, excessively high humidity pro- This duces undesirable condensation upon the walls. 7

By the present invention, the difliculties and ob- Jections previously encountered are eliminated and, to this end, it is a primary object of this invention to provide a refrigerator having novel means for controlling the humidity conditions therein, and for decreasing the average temperature differential between the air within the compartment and the walls thereof.

More particularly, it is an object of the present invention to provide a refrigeration apparatus having novel means for removing moisture from the cabinet air, as and when required, and for lowering the temperature of said air with respect to that of the wall structure.

To this end, the invention contemplates the provision of humidity-responsive means for withdrawing air from the food compartment, passing it in heat exchange relation with a cold zone and re-injecting it into the compartment after its temperature has been reduced and after the desired degree of moisture has been removed therevention resides in the provision of such refrigeration apparatus, having a. moisture-removing evaporator portion which affords heat transfer capacity in addition to that supplied by the evaporator arranged to cool the walls of the main food storage compartment.

These and other objects and advantages of the invention may be more clearly understood by reference to the following description and to the accompanying drawings in which:

Fig.1 is an elevational and partial sectional view of a refrigerator embodying the invention,

the refrigerator being shown with the main food I compartment door removed therefrom;

Fig. 2 is a sectional view taken on the line 2-4 of'Fig. 1, and with the main door included in the assembly;

,Fig. 3 is an enlarged perspective view from therear of the refrigerator inner tank structure, certain portions being broken away for the sake of clarity in illustration;

Fig. 4 is an enlarged sectional view taken on the line 4-4 of Fig. 1; i

Fig; 5 is an enlarged sectionalview taken on the line 5-5 of Fi 2; and

Fig. 6 is an enlarged sectional illustration of a detail of the construction. a

In Figs. 1 and 2 of the drawings, there is illustrated a domestic refrigerator of the mechanical type which includes an outer shell 3, which may.

be of any well-known type and construction, and an inner metal shell or liner member 4 providing the, main food storage space, indicated generally at 5. This space 5 is fitted with a plurality of shelves 6, of any desired type. Vertical and horizontal breaker strips 1 and 8, respectively, of low thermal conductivity, are fitted around the forward marginal edge of the cabinet opening,

while thermal insulation, portions of which are indicated at 9, completely surrounds the inner liner member 4 as well as the outside surfaces of the cooling means presently to be described. The

cabinet is provided with a door I0, said door being adapted to seat thereagainst in the plane .0: the reaker'strips and flpasillustrated my J A machinery compartment ii is located in the ,lower portion of the cabinet structure, which; 4 compartment houses the compressor unit indicated generally at l2; The main, sharp-freezing evaporator-"storage section is shown at I! and includes, generally,- a relatively large well-typey,

storage area H,- to which. access maybe had.

through. a door l5, and a smallerice-freezing f space indicated at [8. Thisevaporator may be supported within the refrigerator in any con-1 venient manner, as for example, by welding its-I outer vertical walls to an inturned flange formed about the lower edges of the inner liner 4. Cer-- M tainfeatures' of the particular evaporator 1111139. trated,- are disclosed and claimed. in. the co- 1S pend ng application of Donald E. Dailey','seriall No 515,950, flied December 28,. 1943, anda's such features, per se, form no part of the present invention, detailed description thereof' is not deemednecessaryrc i v k :Intheembodimentillustrated, and as best 'seenin Figs. 2 and 4; a double-thickness insulat ing partition- I! provides the floor for the main storage compartment 5; this partition being in-'" terposed between themainevaporatorsectionst 1 and the storage compartment 5, in orderto make it possible tooperate said compartment at rela-'-' tivelyhigh temperaturesas compared with the temperature of 'thev evaporator sections it andj l8, and to prevent the undesired frosting-out or; I moisture present in said compartment}. As clearlyappears in Fig, 4,! gasket members)": i 1 surround the partition i1, said gaskets being in'-' terposedbetween the partition members and the adjacent wall portions of the inner liner 4, ,e Referring to Fig. 3, it will be seen that the main cuitrwillhave 'a capacity: whi h more h sufficient to meetthe maxmum heat load con dition which may be encountered in practice, dur-' ing' the different cycles of operation presently-te bedescribed.

- It should be'borne in. mind that the inven-{J tionis particularly concerned with an arrangement in which the major portion of the cooling-j f. "of the main food storage compartment 5 isac- 'complished through the medium of the secondary "I v 1 tubing l9; while additional heat transfer capacity'is provided and the elimination of desired humidity from said compartment is ac- I complished by effecting periodic circulation 'of compartment air through the several ducts ap-Yl pearing in Fig. 3,-and thence into the passage.

28. arranged iniheat exchange relation'with the.

primary 'evaporator tubing At; this 'pointgflu there is a transfer of latent heat from the moisture-laden air to the low temperature tub-f ing 25 and, consequently, some of the moisture is a condensed upon the surrounding'surfaces. Fol-llowing this,'the air whoseabsolute humidityhas;- -.nowbeen substantially decreased, is re-injected into the food storage-compartment, and, combining with the air. in said compartment,- acts to. lower'the overall relative humidity therein This circulation is effected, as and when required by means of a motor and associated fan 3i 3 operable periodically in response to the humidity 1 In the embodiment'illustrated, this controlled" i circulation is initiated by a humidostat 32 (see. Figs. 1 and 2) which may be of any desired type. I Since the invention is not concerned with the.

conditions existing in the'compartment I. I

-. particular humidostat employed, a description of foodstoragesection B is cooled, primarily, by

means of tubing 19 secured in convoluted ar 3 rangement about the exterior surface of the inner linen-andconstituting the-evaporator portion of" a secondary, refrigerant circuit of known type.

' the details thereof is not necessary herein. However, it willbe understood that the humidostat is adapted to initiate operation of the motor 30%;

when the relative humidity in compartment i-has risen'to a point just above a predetermined value. 1 Further, while .humidostat control is Preferably employed, it. will be evident that it would be 7 possibieto effect periodic actuation ofthe air which constitutes a series-connected portion of a f the main primary circuit utilized to effect refriseration of thesharri-freezin; compartments H and IS. A detailed description of this portion of the apparatus is not necessary herein, since the invention is not concerned therewith. QAlthough any convenient form of primary re- 1 0' frigerant circuit may be employed, there has been 1 illustrated an arrangement in which (referring g to Figsrl to 3) the liquid refrigerant formed in the condenser 2l is delivered to-a central shelf .j 22, in-the ice freezing compartment, said delivery p 1 being effected through a capillarytube 23 arranged in heat exchange relation with the suction 1 line 24. From the entry point 230, the volatile refrigerant is deliveredfto passages 26 arranged F about evaporator storage section l3, after which it flows through a lower passof tubing 28 (see Fig. 4) and is delivered tothe small auxiliary evaporator element 20 by means of an'upwardly 5 extending conduit 21. After being passed in heat exchange relation with the refrigerant of the secondary system, the primary refrigerant is returned to the compressor unit through the down wardly extending suction conduit shown at in Figs.- 1 and 3. It should beobserved that the lower pass of tubing 25, referred .to above, is arranged in closeproximity to an airflow passage 28, to be described in greater detail hereinafter.

It is assumed, of course, that the primary circirculationfan by other means. For example, i

the motor- 80 could be energized at periodic.

timed intervals, in accordance with average humidity conditions found in practice in anyplac ticular locality, With such an embodiment, the device 32 should be understood as representing an automatic timing device of any desired known form. While such operation would not result in .as high 'a degree of control of the relative humidity as can be obtained by the use of a humidostat, it would be possible to prevent the existence of undesirably high humidity conditions without causing the humidity in the refrigerator to dropbelow a desired minimum. This will be apparent from the fact that ii, for example, the passage i 28 is maintained at a mean temperature of 33 F., 1 l (which will create a condition of IOU-percent relative humidity at 33,if condensation is. occurring) the air would be re-iniected into the compartment at approximately 72 relative humidity, at the 40 F. temperature preferably maintained in said compartment. under certaincircumstances, be desirable to circulate the compartment air even if the conditions were not such that condensation would occur in the passage 28, and such circulation is also con.- templated by'the present invention.

Referring now with more particularity to the construction and operation of the air circulation apparatus, it will appear that the duct work, see for example the passage 29, preferably comprises It might. I

a passage of airfrom structure 42- secured -iri-air-itight, arrangemen 1 with section," of theyprimary evaporator, as by A means of the; flanges shown at flax As appears half-round tubing securedftol fllel mrdfm: cfliner .4, by. means of flanges .llyyvhi h may,

1' bonded to said wall in any convenientigmanner A horizontal air-withdrawal duct-r-ll4 f extends v across a Substantial portion of the-width "of liner;

4, in the lower porti 'nthereof; and as appears v in Figs. 1 and 2,- an aperture fl'is'provide'd in back "ofthe'upper portion of. the liner member:'-;

the liner wall beinzapertured at TI, to permi compartm l? Extending downwardly iii-anthe in a e-allay 34, is a short connection ductll which,' as may; be seen from'a'comparison of Figs: 3.and 8,, is-in communication with a generally L-shaped saddl defines the passage 28 is dividedintoiniiow and" outflow sections 39 and"; respectively. by means: of a partition membershownatllt Referenceto Figs. 3, A} and 5-willshow that-thefan li-is inf communication with outflow section 40, whilethe' downwardly exten'ding' ductiil isqin free com j munication'with thqinflOW-RElQn19p-f; The air flow isdesignated by arrows'a .in the drawingsififrom 'whichfit willb'e' apparentthat" air is 'withdrawnEfrom' the compartment? through vduct 34, passes downwardly .into (the.

inflow section}! ofsaddle structure 42, thence. forwardly through said sadd1e structure, around the forward end of partition 4| (as best seen in Fig. 4) and thence-throughoutflow portion 40 .and the blower unit ll. From this point, the air is directed upwardly through the vertical passage a 29, from whence it is delivered toduct fl'forreinjection into'the main food storage compart ment. .-As appears in Fig. 5, a plurality of 43 depend from the supporting plate 44, said'flns-f' F serving to promote heat transfer between the air When the fan a condition of excessive humidity in ,the compart ment 5, the invention, contemplates the main- ,tenance' ofv the, temperature of .air; passingthrough the inflow and outflow channels at a' This is temperature above the freezing point.

said duct-so; into the food" operation,

' the liner wall intre istr with duct portion'. A similar air injection duct 38. extends across theso most clearly in Fig; 3,1111; saddle structurewmch v desirable in order that the moisture condensed at I this point will not be frozen and thereby restrict the passage area, and'to'this end, a sheet of in-v sulating material 45 is preferably interposed bepassages; As will now be evident, the moving air below the dew point, and the resulting condensate tween the tubing 25 and said inflow and outflow gives up if portion of its heat to'the tubing 28, thereby'reducing the temperature of said air surface, it isposslbl t frosting zones within the winger-am; hydration ofs. therefore-prevented,

compartment air is then caused to circulatein heat, exchange relation with the primary evaporator tubing 28 and is re-injected into the refrigshownby theair flow indications on the drawings 1. v v 31ml This air circulation is continued until suflicie'nt percentage of relative humidity iii-compartment the motor circuit. -i a I the foregoingdescriptiomit will be understood"thatthetinvention provides a "refrigerato'r having a-novel. itygcont'r'ol meansr 7 ing -air'is 'cooled'vduring the circulating process additional tothat' tubing which is refrigerating the -compartment through the walls thereof;

" Further, this humidity control is effected with-i out attendant undesirable frosting, .and by an arrangement which lends itself well to the usage I of a plurality of zones maintainedat temperatures be refrigerated. a

v rying in accordance with the demands of the variousfoodstuifs to 1 claim: i I, 1.,In a. refrigerator having a walled portion defining a high humidity food storage compartto maintain said compartment at non-frosting temperatures, second cooling' means providing heat transfer capacity in addition to'that provided by said first cooling means, and means rev sponsive to humiditycondition within said oompartment for effecting intermittent forced circulation of thecompartment air in heat exchange relation with said second cooling means to condense moisture from saidair and to cause the temperature of the air in said compartment to flows to a sump or trap 48' formed in the rear portion' of outflow section 40. From this sump the liquid is delivered through pipe 41 into a recep- Y tacle (not shown) which is preferably'in association with the compressor unit II, in order that the condensate may be evaporated by the heat of said unit, and in addition, may provide cooling fortheunit. 4 l" Under normal conditions of operatiomi'. te., when the relative humidity in compartment I is below a desired predetermined maximum, the fan Si is not in operation and the storage compartment is cooled solely by the secondary tubing I! arranged about the liner walla. Since sumcient approach that of the walls thereof.

-, 2.- In a refrigeratorhaving a walled portion I r defining a high humidity food storageccmparh. I

ment, first coolingmeans in heat exchange relation with walls of the compartment and comprising a volatile refrigerant system, adapted to I maintain said compartment at non-frosting temperatures', second cooling means comprising a J I volatile refrigerant system providing heat trans-v fer capacity in addition to that provided by said' first cooling means, and means for effecting controlled forced circulation of the compartment air in heat exchange relation with said second cooling means.

3.'In a refrigerator having a walled portion tubing is used to present a large heat exchange I5 defining a high humidity food storage oompart-.

maintain compartment B at relatively lowtemperatures, for example in" the neighborhood Mail-40'1" without creatingthe foods within .lthe compartment T However,- should the humidity rise to an undesirably high ,value, whichtmay occur very 'fre- H quently in certain climatelithe humido'stat u 'willrespond' thereto and initiate operation of the-motor}! audits associated blower. .i'lhe orator: 'in tthe'manner'previously described, and

moisture'has been removed in the passages of the I saddle-like, structure 42, to restore ,the",-desired I, vatwhich time the humidostat disconnectdladvantageous humid- I It is particularly'to'benotedthatthe circulatby -an.zevaporator having heat transfer capacity thereby not onlyfurther cooling the compartment as a whole,-but aso reducing the air temperature with respect toth'at off the walls. This latter I effect, as willnow' be. understood, minimizes the tendency oiwthe free moisture to deposit upon 'said walls.,.I. i C

ment, first cooling means in heat exchange rela-. tion with walls of the compartment and adapted ment, a secondary refrigeration system including an evaporator in heat exchange relationwith walls of the compartment and adapted to maintainsaid compartment at non-frosting temperatures, a primary refrigeration system having ,a

portion thereof arranged in heat exchange rela tion with a portion of said secondary system, said value and is adapted to maintain said circulation until the relative humidity is reduced to said predetermined value. 5. In a refrigerator having a walled portion defining a high humidity food storage compartment, a secondary refrigeration system including an evaporator in heat exchange relation with walls of the compartment and adapted to maintain said compartment at non-frosting temperatures, a primary refrigeration system having a portion thereof arranged in heat exchange relation-with a portion of said secondary system, said primary system inciuding an evaporator having an airflow passage in heat exchange relation therewith, means responsive to humidity condition within said compartment for effecting intermittent forced circulation of the compartment air through said passage in heat exchange relation with said primary evaporator to condense moisture from said air and to cause thetemperature of the air in said compartment to approach that of the walls thereof, and means limiting the temperature reduction effected in said passage to a value above the freezing point of water.

6. In a refrigerator having a walled portiondeflning a high humidity food storage comparttion with walls of the compartment and comprising a volatile refrigerant system adapted to maintain said compartment at non-frosting temperatures, second cooling means comprising a volatile refrigerant system including an evaporator adapted to operate at temperatures below those prevailing in said compartment and having an airflow passagein heat exchange relation therewith, means responsive to humidity condition within said compartment for effecting intermittent forced circulation of the compartment air through said passage in heat exchange relation with said evaporator to condense moisture from said air and to cause the temperature of the air in said compartment to approach that of the walls thereof, and means limiting the temperature reduction effected in said passage to a value above the freezing point of water. i

7. In a refrigerator having a walled portion defining a high humidity food storage compartment, first cooling means in heat exchange relation with walls of the compartment and comprising a volatile refrigerant system adapted to ment, first cooling means in heat exchange relamaintain said compartment at non-frosting temperatures, second cooling means comprising a volatile refrigerant system including an evaporator adapted to operate at temperatures below those prevailing in said compartment and having an airflow passage in heat exchange relation therewith, means responsive to humidity condition within said compartment for effecting intermittent forced circulation of the compartment air through said passage in heat exchange relation with said evaporator to condense moisture from said air and to cause the temperature of theair in said compartment to approach that of the walls thereof, and insulation means interposed between said evaporatorand said passage and limiting the temperature reduction effected in the passage to a value above the freezing point of water.

8. A refrigerator comprising a plurality of refrigerated zones, one of'which is adapted to be maintained at a condition of high relative humidity, cooling means comprising a volatile refrigerant evaporator adapted to maintain said one zone at a non-frosting temperature and creating within the zone an area maintained at a temperature below that of the air in said zone,

cooling means comprising a volatile refrigerant evaporator adapted to operate at a temperature below that prevailing at any location in said one zone, and arranged to cool another of said zones, means for effecting forced circulation of air from said one zone in heat exchange relation with said second-mentioned cooling means, and means for controlling the operation of said air circulating means, said last means being adapted to initiate operation of said air circulating means upon the relative humidity in said one zone exceeding a predetermined value.

9. A construction in accordance with claim 8, in which said second-mentioned cooling means is adapted to operate at a sub-freezing temperature and in which construction there is included an airflow passage in heat exchange relation with said second mentioned cooling means through which the circulating air is passed, the arrangement further being characterized in that the heat exchange relation between said passage and said cooling means is such as to limit reduction of the air temperature to a value above the freezing point of water.

' MALCOLM G. SHOEMAKER.

REFERENCES CITED The following references are of record-in the