US2946206A - Refrigerator employing secondary refrigeration system - Google Patents

Description

July 26, 19 60 A. e. HELLSTROM REFRIGERATOR EMPLOYING SECONDARY REFRIGERATION SYSTEM Filed Aug. 17, 1956 3 Sheets-Sheet 1 )VZENTOR.

BY; f 7

July 26, 1960 A. e. HELLSTROM 2,946,206

REFRIGERATOR EMPLOYING SECONDARY REFRIGERATION SYSTEM Filed Aug. 17, 1956 3 Sheets-Sheet 2 WM /IZVENTOR.

BYg y 7 I y 1960 A. G. HELLSTROM 2,946,206

REFRIGERATOR EMPLOYING SECONDARY REFRIGERATION SYSTEM Filed Aug. 17, 1956 Y 5 Sheets-Sheet s United States Patent REFRIGERATOR EMPLOYING SECONDARY REFRIGERATION SYSTEM Axel 'Gosta Hellstrorn, .lohanneshov, Sweden, assignor to Aktiebolaget Elektroiux, Stockholm, Sweden, a corporation of weden Filed Aug. 17, 1956, Ser. No. 604,711

Claims priority, application Sweden May 14, 1956 7 Claims. (Cl. 62-334) My invention relates to refrigeration, and more particularly concerns the cooling of the thermally insulated interior of a refrigerator with the aid of a secondary refrigeration system.

It is an object of my invention to provide an improvement for cooling the interior of a refrigerator with the, aid of a secondary refrigeration system whereby the cooling effect obtained is better distributed.

Another object of my invention is to provide an improvement for transmitting cooling effect to the interior of a thermally insulated inner shell or liner with the aid of a secondary refrigeration system operatively as sociated with primary refrigeration apparatus having a cooling element which not only is employed to transmit cooling effect to the secondary system but also is in heat exchange relation with the inner shell.

A further object of the invention is to provide an improvement whereby primary refrigeration apparatus, a secondary refrigeration system and an inner shell form a compact unitary structure which is movable as a unit into functional relation with the outer shell of a refrigerator cabinet containing insulation.

A still further object of the invention is to provide an improved refrigerator comprising two units capable of being moved into and out of functioning relation, the outer shell of the cabinet and insulation therein forming one of the units, and primary refrigeration apparatus, a secondary refrigeration systemand an inner shell of the cabinet forming the other of the units.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the claims. The invention, both as to organization and method, together with the above and other objects and advantages thereof, will be better understood by reference to the following description taken in connection with the accompanying drawings forming a part of this specification, of which: I

Fig. 1 is a vertical view, partly in section, of a refrigerator embodying the invention, V 7 Figs. 2., 3 and 4 are enlarged fragmentary sectional viewsof parts shown in Fig. 1 to illustrate details more clearly;

Fig. 5 is a perspective view of the inner shell or liner of the refrigerator illustrated in Fig, 1 and cooling elementsin thermal exchange relation with the exterior surface thereof; and

Fig. 6 is an enlarged fragmentary sectional view taken at line 5-5 of Fig. 4. 7

Referring toFig. 1, the invention is shown in connection with a refrigerator comprising a cabinet 10 having a one-piece inner metal shell or liner 11 arranged to be supported within an outer metal shell 12 and insulated with. any suitable insulating material 14. The inner metal shell. 11 definesa thermally insulated storage space 15 for storing frozen food. packages and freezing meat, fruit, vegetables and other foods as well as fruit juices and other liquids. Access to the storage space 15 is afforded through the open top thereof which is adapted to be closed by a removable closure or lid 16 containing a and side walls of the shell by clamps 18 secured thereto,'

as by welding, for example. 7

The evaporator 17 is connected to a condenser 19 which is in heat exchange relation with a low temperature cooling element 20. The evaporator 17 and condenser 19 connected thereto form a secondary refrigeration or heat transfer system, the evaporator being of the flooded type and located at a lower level than the condenser. The evaporator'l'l and condenser 19 form a closed fluid circuit which is partly filled with a suitable volatile fluid; such as methyl chloride, ammonia or the refrigerant available under the trademark Freon, for example, that evaporates'in the evaporator 17 and takes up heat, thereby producing cold. The vapor flows from the evaporator 17 into condenser 19 in which vapor is cooled and condensed by cooling element 20. The liquid condensate formed in condenser 19 returns by gravity to the'evaporator 17.

It will be seen in Figs. 1 and 5 that the evaporator 17 and condenser 19 essentially are of helical form with each straight pipe section thereof in heat exchange relation with the outer surface of the inner metal shell 11; Further, the straight pipe sections of the evaporator 17 at the side walls of the shell are inclined upwardly from the horizontal to form an ascending path of, flow for vapor formed therein. Liquid condensate flows bygravity to the evaporator 17 in the downwardly inclined sections of the condenser 19, the pipingforming these parts of the secondary heat transfer system being sufficiently large to allow vapor and liquid to pass each other freely. In ad-, dition, the secondary heat transfer system includes a connection 21 betweenthe lower end of evaporator 17 and the upper end of condenser 19' which may be provided with a suitable valve 21a for charging the second system with a suitable volatile fluid.

The low temperature cooling element 20 desirably forms a part of primary refrigeration apparatus of any suitable type. Byway of example, the primary refrigerae tion apparatus may be of an absorption type containing an inert gas orpressure equalizing agent. In such apparatus, refrigerant vapor expelled from-solution in a generator 22 by heating'flows through a conduit 23 to a condenser 24in which it is liquefied. The liquid refrigerant, such as ammonia, for example, flows from condenser 24 through a conduit 25 to an upper part of low temperature cooling element 20 in which the liquid evaporates and diffuses in the presence of aninert gas, such as hydrogen,

for example, thereby producing a refrigerating effect for condensing vapor in the condenser 19. p

The resulting gas mixture, of refrigerant'and inert gas flows from the upper end of cooling element 20 through a conduit 26, one passage of gas heat exchanger 27, conduit 28 and absorber vessel 29 to the lower end of absorber coil 30 where refrigerant vapor is absorbed into liquid absorbent, such as water, which enters through a conduit 31. Inert gas weak in refrigerant is returned to cooling element 20 in apath of flow including conduit 32, another passage of gas heat exchanger 27 and a conduit 33. Absorption liquid enriched in refrigerant in the absorber 30- passes into the absorber vessel 29: and flows therefrom through a conduit 34 to generator 22 where it is heated and refrigerant vapor again is expelled. out of solution. The weakened absorption liquid from which refrigerant. haslieen'expelledas vapor. is conducted from the generator 22 through conduit 31 to again absorb refrigerant vapor. It will be seen that a part of conduit 25 is in heat exchange relation with the gas heat exchanger 27 to effect pre-cooling' of liquid refrigerant in its path of flow from condenser 24 to the upper end of coolingelement 20. Further, the portion '25a of. conduit'25 may be arranged in heat exchange-relation with conduit 26 through which the cool mixture of refrigerant vapor and inert gas flows upon leaving cooling'element 20, thus effecting additional cooling of liquid refrigerant before it enters the cooling element in the presence of the inert gas.

The upper end of conduit 26 is formed with raised portion or hump 26a to insuredownward flow of liquid refrigerant in the cooling element 20.

- In order to simplify the drawings, part of the primary refrigeration apparatus has been shown only diagram matically, apparatus of this type which includes provisions to insure upward flow of inert gas through the cooling element 20 in counterflow to liquid refrigerant being well known.

. The parts of the primary refrigeration apparatus just described, whose relative positions are substantially fixed, usually are formed of iron or steel when ammonia and water are employed as the refrigerant and liquid absorbent, respectively. Therefore the piping for the cooling element 20 which is connected by conduits to other parts of the primary refrigeration apparatus and forms a unitary part thereof may be formed of such ferrous metal.

In accordance with my invention, inorderthat the assembly of parts will be compact and provide a refrigerator of a given capacity which will occupy a minimum amount of space, the cooling element 20, which is in heat exchange relation with the condenser 19 of the secondary heat transfer system, is arranged in heat exchange relation with the inner metal shell or liner 11 of the cabinet 10. As best shown in Figs. 5 and 6, the primary cooling element 20 comprises piping disposed about the four sides of the inner liner 11, the piping being disposed alongside of and in heat exchange relation with the condenser 19 of the secondary heat transfer system. The primary cooling element 20 and condenser 19 may be fixed to the exterior surface of the inner liner 11 in any suitable manner, as by clamps which are secured thereto at 36 and 37, as by spot welding, for example, as shown in Fig. 6. In this way, the primary cooling element 20 and condenser 19 are held in good heat exchange relation with one another and the outer surface of the inner liner 11. During normal operation of the refrigerator illustrated in the drawings and just described, heat is effectively abstracted from the interior of space 15 by the evaporator 17 of the secondary heat transfer system in the manner explained above. Inaddition, the primary cooling element is advantageously employed to abstract heat from the upper part of the space 15 by virtue of its location at the upper part of the secondary heat transfer system. By transmitting cooling effect in this manner to the storage space 15, the vertical temperature gradient in the latter is reduced sharply, particularly when the storage space is loaded. Accordingly, it is possible to increase the height to which frozen food packages can be safely stored in storage space 15 without any thawing of frozen food packages in the uppermost layer, and without placing an additional burden on the primary refrigeration apparatus to maintain the storage space at the desired low mean or average temperature.

Also, if the secondary heat transfer systemshould fail and render evaporator 19 ineifective to transmit cooling effect to the storage space 15 and its contents, the foodstuffs in the storage space will still be protected since primary cooling element 20 will still be operable to transmit cooling effect to the interior of the storage space.

In order to facilitate servicing and inspection of therefrigeration equipment, particularly the secondary heat transfer system which forms a unitary part of the primary refrigeration apparatus, the refrigeration equipment is mounted in the cabinet 10 in such a manner that it and the.

inner metal shell 11 can be removed as a unit from the outer shell of the cabinet. Accordingly, the refrigeration equipment forms a unitary structure which includes the inner liner or shell 11 and a plate 38 which is fixed to parts of the primary refrigeration apparatus in any suitable manner (not shown).

The plate 38 forms the outside panel of the rear insulated wall of the cabinet 10, the lateral side walls 12a and top 12b of the outer shell 12 extending or projecting beyond the plate 38 to provide a vertical compartment 39 in which parts of the primary refrigeration apparatus are housed. During operation of the primary refrigeration apparatus, natural draft circulation of air is induced in compartment 39 to effect air cooling of the absorber 30 and condenser 24, such cooling air flowing upwardly in the compartment and passing therefrom through openings (not shown) at the rear part of the top 121) of the cabinet.

The cabinet 10, which includes a base 41, is so constructed that the inner liner 11, which forms a unitary part of the refrigeration equipment, can be readily removed from the cabinet and placed back in position whenever necessary. Referring to Fig. 1, the cabinet 10 includes a base 41 which is formed in part by the front wall 12c and lateral side walls 12a of the outer shell 12. A horizontal plate 42 forming the outer panel of the bottom insulated wall is fixed to the front and lateral side walls of the outer shell 12 and also to the bottom part of a vertical panel 43 having an opening therein sufliciently large for the inner liner 11 to pass therethrough, the panel 43 also being fixed to the top 1% and lateral side walls 12a of the outer shell.

The bottom part of the rear vertical panel 43 is provided with an angle member 44a which is at a slightly higher level than an angle member 44b fixed to theinner surface of the front wall 12c of the outer shell. A pair of U-shaped members 45a and 45b are fixed to the angle members 44a and 44b, respectively, for holding a pair of elongated bars 46 which are employed to support the bottom of the inner liner or shell 11. The closed ends of the U-shaped members 451) are fixed to the inside surface of the front wall 12c of the outer shell, and the closed ends of the U-shaped members 45a are fixed to the angle member 44a, thus providing supporting places at substantially the same height for the ends of the bars 46 which may be formed of any suitable material having poor thermal conductivity, such as wood, for example.

In order to simplify the drawings, the gas heat exchanger 27 of the primary refrigeration apparatus has been illustrated in Fig. 5 as an essentially straight component or part of the system. To provide a compact arrangement of parts, it is advantageous to employ a gas heat exchanger which is bent intermediate the ends thereof, a first section 27a of which is embedded in the insulation of the rear insulated wall of the cabinet and extends lengthwise thereof and a second section 27b of which is perpendicular to the first section and extends rearwardly into the vertical apparatus compartment 39, as shown in Fig. l.

The conduit connections in Fig. 1 corresponding to conduits 26 and 33 in Fig. 5 serve to support primary cooling element 20 and inner liner 11 on the inner section 27a of the gas heat exchanger 27. Also, a member 47 may be fixed to a lateral side wall of the inner liner 11 and to the gas heat exchanger 27, respectively, to provide additional support for the inner liner on the primary refrigerating apparatus. Further, a bridging member 48 formed of suitable insulating material, such as wood, for example, may be located between the rear wall of the inner liner 11 and the plate 38, such bridging member 48 being fixed to these parts at 49 and 50, respectively.

The top opening of cabinet 10 is defined by a frame 51 of annular form which may be made of suitable insulating material, such as wood, for example. The frame s na ed at 52 o one am o a! e be 53 of as asaaaoe shape; the other armof which is'secured, as by welding; to the underside of the top 12b of the cabinet at the vicinity of the opening therein.

Each of the three sides of frame 51 at the front and lateral. sides of cabinet is formed with a groove 54 which receives an outwardly extending flange He at the top open end of the inner liner 11, as best shown in Fig. 2. The side of frame 51 at the rear of the cabinet is of shorter depth than the other three sides and the bottom side 51a terminates at about the level of the grooves 54 to provide a space54a whichreceives one side of the outwardly extending flange 11a of inner liner 11, as best seen in Fig. 3. To form a good seal between the frame 51 and flange 11a of the inner liner 11, a suitable sealing material 54b, such. as that sold under the trademark, Permagum,. for example, desirably is forced into the grooves 54 and space 54a. A finishing strip 55 which is resilient in character and may be. formed of plastic material desirably is positioned about the frame 51, the strip 55 having a lip 55a which is held in place at the peripheral edge of the opening in the top 12b of the cabinet. The bottom part of the strip-55' may be removably secured at 56 to the frame 51.

Essentially, the refrigerator illustrated in the drawings and described above comprises two main units or com ponents which are readily separated whenever inspection or, repair of the refrigerating system is necessary. One component comprises the base 41, outer shell 12 and insulation 14 retained therein at the bottom, front and lateral sidewalls, and the other component comprises the primary refrigeration apparatus, secondary heat transfer system, inner liner 11 and insulation for the rear insulated wall of the cabinet 10. The plate 38, which forms, the outside panel of the rear insulated wall of the refrigerator cabinet 10 and is fixed to and form a unitary part of the parts making up the primary refrigeration apparatus, is removably secured at 38a to the apertured vertical wall member 43, as best shown in Fig. 4.

When it becomes necessary to inspect or repair the refrigerating system, the finishing strip 55 is detached and the sealing material 54b removed. The connections 38a at the rear insulated wall of the cabinet 10 are loosened, which then allows the primary refrigeration apparatus, secondary heat transfer system, inner liner 11 and insulating" material between the rear wall of the inner liner 11 and the vertical plate, 38 to be moved as a unit. It will be: understood that when this is done, the part of flange 11a of the inner liner 11 which is at the vicinity of space 54a can immediately move rearwardly, while the remaining parts of flange 11a can freely detach themselves from the grooves 54 in the other sides of the frame 51. After the initial rearward movement of the plate 38, it may be necessary to compress the insulation at the rear wall of the cabinet about the opening in plate 43 in order to work it free and allow it to pass without diificulty, along with the secondary heat transfer system and inner liner 11, through the opening in the plate 43.

When the two units or components of the refrigerator are reassembled and brought together in functioning relation, the insulation is positioned between the inner liner 11 and plate 38 in the event it has been removed, and the inner liner 11 is inserted through the opening in the plate 43 and positioned on the elongated bars 46. After tucking in the insulation about the opening in the plate 43, the connections 38a for plate 38 are tightened. With the flange 11a of inner liner 11 now correctly positioned at the vicinity of the frame 51, sealing material 54b, desirably having the physical characteristics of a non-drying cement, may again be inserted in the grooves 54 and space 54a to effect a seal between the frame and inner liner 11, after which the finishing strip 55 may be connected about the frame opening.

In view of the foregoing, it will now be understood that an improved refrigerator has been provided which is extremely compact and can be readily repaired or examined when necessary. Although not shown, it will be understood that all of the seams of the outer; shell 12 of the. cabinet may be internally sealed with a, suitable material;

like asphalt, for example. Such a sealing material may be employed, for example, at the bottom side of member- 53 to seal the latter to the underside of the top 12b of the cabinet 12 and to the frame 51. Mineral wool or like material in the form of batting trimmed to fit the insulating wall sections at the bottom, front and lateral side: walls of the outershell 12 may be used for the insulation 14, in which case the bars 46 are placed in position after. the bottom insulating section has been placed against the bottom plate 42. The insulation between the inner liner 11 and plate 38 may be of the same kind as that used in the other walls of the cabinet 10. A suitable scaling agent 38b, like the seahng agent 54b, may also be employed at the peripheral edge of plate 38 when the latter is secured in place by the connections 38a to provide an airtight seal for the insulation retained in the cabinet 10.

Modifications of the embodiment of my invention which I have described will occur to those skilled in the art, Therefore, as I desire my invention not to be limited to the particular arrangement set forth, I- intend in the claims to cover all those modifications which do not depart from the spirit and scope of the invention.

What is claimed is:

1. A refrigerator comprising a cabinet having spaced apart inner and outer shells and insulating material therebetween of which a part thereof, is removable, said inner shell defining a space to be cooled, primary refrigeration apparatus comprising a coolingelement disposed exteriorly of said space, a secondary heat transfer system disposed exteriorly of said space which, contains a refrigerant and includes a condenser in heat exchange relation with said cooling element and an evaporator arranged to abstract heat from said space, the aforementioned parts comprising two units movable into and out of functioning relation, one of said units comprising said outer shell and a major porton of the insulating material and the other of said units comprising unitary structure including said primary refrigeration apparatus and secondary heat transfer system and inner shell, said other unit being movable with respect to said one unit in apath which includes a zone normally occupied by the-removable part of the insulating material, said outer shell including a wall member having an opening and a hollow frame fixed to such wall member at the opening therein, said inner shell having an opening which is at the vicinity of said frame when said units are moved intofunctioning rela tion,the openings in the inner and outer'shells and hollow frame at the vicinity of the openings defining an access passage to said space, said inner shell at the vicinity of the opening therein having an element, and said hollow frame having a surface-engaging part which is engaged by said element when said units are in functioning relation.

2. A refrigerator comprising a cabinet having spaced apart inner and outer shells and insulating material therebetween of which a part thereof is removable, said inner shell defining a space to be cooled, primary refrigeration apparatus comprising a cooling element disposed exteriorly of said space, a secondary heat transfer system disposed exteriorly of said space which contains a refrigerant and includes a condenser in heat exchange relation with said cooling element and an evaporator arranged to abstract heat from said space, the aforementioned parts comprising two units movable into and out of functioning relation, one of said units comprising said outer shell and a major portion of the insulating material and the other of said units comprising unitary structure including said primary refrigeration apparatus and secondary heat transfer system and inner shell, said other unit being movable with respect to said one unit in a path which includes a zone normally occupied by the removable part of the insulating material, said outer shell having a first opening through which said primary cooling 7 element-and secondary heat transfer system and inner shell pass when said units are moved into and out of functioning relation, said outer sliell having a second opening, said inner shell having an opening at the vicinity of and spaced from the-second opening of said outer shell when said units are in functioning relation, and bridging means to close the gap between the second opening in said outer shell and the opening in said inner shell. 3. Apparatus as set forth in claim 2'. in which said inner liner and its opening define a space having a top access opening, said cooling element being heat conductively connected to said condenser and also to the exterior surface of said-inner shell, and said evaporator being disposed at a lower level than said condenser and heat conductively connected to the exterior surface of said inner shell.

- 4. A refrigerator comprising a cabinet having spaced apart inner and outer shells and insulating material therebetween of which a part thereof is removable, said inner shell defining a space to be cooled, primary refrigeration apparatus comprising a cooling element disposed exteriorly of said space, a secondary heat transfer system disposed eXter-iorly of said space which contains a refrigerant and includes a condenser in heat exchange relation with said cooling element and an evaporator arranged to abstract heat from said space, the aforementioned parts comprising two units movable into and out of functioning relation, one of said units comprising said outer shelland a major portion of the insulating material and the other of said units comprising unitary structure including said primary refrigeration apparatus and secondary heat trans fer system and inner shell, said other unit being movable with respect to said one unit in a path which includes a zone normally occupied by the removable part of the insulating material, said outer shell including a wall member having an opening and a frame fixed to such wall member at the opening therein, said inner shell having an opening which is at the vicinity of said frame when said units are moved into functioning relation, the openings in the inner and outer shells and frame at the vicinity of the openings defining an access passage to said space, said frame being rectangular and having a groove at at least three sides thereof, said inner shell at the vicinity of the opening therein having an outwardly directed flange received by said groove when said units are in functioning relation.

5. A refrigerator comprising a cabinet having spaced apart inner and outer shells and insulating material therebetween of which a part thereof is removable, said inner shell defining a space to be cooled, primary refrigeration apparatus comprising a cooling element disposed exteriorly of said space, a secondary heat transfer system disposed exteriorly of said space which contains a refrigerant and includes a condenser in heat exchange relation with said cooling element and an evaporator arranged to abstract heat from said space, the aforementioned parts comprising two units movable into and out of functioning relation, one of said units comprising said outer shell and a major portion of the insulating material and the other of said units comprising unitary structure ineluding said primary refrigeration apparatus and second ary heat transfer system and inner shell, said other unit being movable with respect to said one unit in a path which includes a zone normally occupied by the removable part of the insulating material, said outer shell including one Wall member having a first opening through which said primary cooling and secondary heat transfer system and inner shell pass when said units are moved into and out of functioning relation, closure means for closing the first opening when said units are in functioning relation, said outer shell including another wall member having a second opening, said inner shell having an opening at the vicinity of and spaced from said second opening when said units are in functioning relation, and bridging means to close the gap between the second opening in said outer shell and the opening in said inner shell.

6. Structure as set forth in claim 5 which includes means for sealing said closure member to said one wall member at the first opening and for sealing said -bridg-. ing means to said inner liner at the opening therein.

7. Structure as' set forth in claim 6 in which said closure means for closing the first opening forms a unitary part of the other of said units, and removable fastening means for connecting said closure means to said one wall member to close the first opening, said fastening means comprising the primary fastening provisions for holding said units in functioning relation. 7 7

References Cited in the file of this patent UNITED STATES PATENTS Tandberg Aug. 25, 1953

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