US2878658A - Freezing compartment for household refrigerator - Google Patents

Description

H. M. ULLSTRAND 2,878,658

FREEZING COMPARTMENT FOR HOUSEHOLD REFRIGERATOR 3 Sheets-Sheet 1 n .N M .n a A fw ff March 2 4, 1959 Filed Feb. 13, 1956 l /l// l March 24, 1959 H. M. -ULLSTRAND 2,878,658

FREEZING COMPART'MENT FOR HOUSEHOLD REFRIGERATOR Filed Feb. 13, 1956 5 Sheets-Sheet 2 IN VEN TOR.' x

March 24, 1959 H. M. ULLSTRAND 2,878,658

FREEZING COMPARTMENT FOR HOUSEHOLD REFRIGERATOR FZ7/@ff LID/7 INVENTOR.

2,878,658 Patented Mar. 24,

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FREEZING COMPARTMENT FOR HOUSEHOLD REFRIGERATOR Hugo Malcolm Ullstrand, Stockholm, Sweden, assignor to Aktiebolaget Elektrolux,lStockholm, Sweden, a corporation of Sweden Application February 13, 1956, Serial No. 565,220 Claims priority, application Sweden February 16, 1955 1 Claim. (CL 62-329) This invention relates to household refrigerators, and for particularly to freezing compartments of refrigerators of this kind.

It is an object of my invention to provide an improvement whereby a household refrigerator operated by refrigeration apparatus may be made more versatile by providing freezing compartments or sections of dilferent sizes depending upon the need for a small or a large size freezing section. I accomplish this by providing for use with a household refrigerator of the absorption type, having a compact freezing section of one size adapted to be maintained at a low temperature by a cooling element, a larger size freezing compartment or section which may be removably secured at will in good thermal exchange relation with the cooling element. y

The invention, together with the above and'other objects and advantages thereof,.will be more fully understood upon reference to the following description and accompanying drawings forming a part of this specilication, and of which:

Fig. 1 is a fragmentary front vertical sectional view of a refrigerator to which the invention is applied;

Fig. 2 is a fragmentary side vertical sectional view, taken at line 2 2 of Fig. l, to illustrate details more clearly; v

Fig. 3 illustrates more or less diagrammatically absorption refrigeration apparatus of the inert gas type which is employed in the refrigerator shown in Figs. 1 and 2;

Fig. 4 is a fragmentary front vertical sectional view of a refrigerator like that illustrated in Figs. 1 and 2 and embodying the invention; and

Fig. 5 is a fragmentary vertical sectional view taken at line 5--5 of Fig. 4.

Referring to Figs. 1 and 2, I have shown a refrigerator comprising a cabinet having an inner metal shell 11 arranged to be supported withinan outer metal shell 12 and insulated therefrom with any suitable insulating material 14. vThe inner metal shell or lining defines a thermally insulated interior 15 into which access is afford-` ed by a door (not shown) which is hinged to the front of the cabinet and in its closed position closes the access opening 16. Hence, the thermally insulated interior 15 provides a storage space formed by the thermally insulated Wall structure of the cabinet 10.

The thermally insulated storage space or compartment 15 of the cabinet 10 is arranged to be cooled and maintained at a low temperature by an evaporator 17 forming part of absorption refrigeration apparatus of a uniform pressure type, like that diagrammatically shown in Fig. 3, in which an inert gas or pressure equalizing uid is employed. In order to simplify Fig. 3, the absorption refrigeration apparatus has been illustrated in amore or conventional manner apart from the refrigerator cabinet shown in Figs. l and 2. In refrigeration apparatus 'of the type shown in Fig. 3, a refrigerant fluid, such as liquid ammonia, for example, is introduced through a conduit 18 into an evaporator 17. In the evaporator `17 the refrigerant huid evaporates and diffuses into an inert gas,

such as hydrogen, for example, to produce refrigeration and abstract heat.

The resulting gas mixture of refrigerant and inert gas lows from the evaporator 17 through an outer passage of a gas heaty exchanger 19 and vertical conduit 20 into an absorber comprising a vessel 21 and a looped coil 22. In the absorber vessel 21 and coil 22 the refrigerant vapor is absorbed by a suitable absorbent, such as water, for example, which is introduced into coil `22 through a conduit 23. The hydrogen or inert gas, which is practically insoluble and weak in refrigerant, returns to the evaporator 17 from coil 22 through a conduit 20a, an inner passage of the gas heat exchanger 19 and a conduit 24.

y From the vessel 21 enriched absorption liquid ows through a conduit 25 and inner passage of a liquid heat exchanger 26 into the lower end of a vapor lift tube 27 of a generator or vapor expulsion unit 28. The generator 28 comprises a heating llue 29 having the vapor lift tube 27 and a boiler pipe 30 in thermal exchange relation therewith, as by welding, for example. By heating generator 28, as by a suitable source of heat, such as an electrical heating element or a gas burner 31, for ex'- ample, liquid from the inner passage of the heat exchanger 26 is raised by vapor lift action through tube 27 into the upper part of the boiler pipe 30. The liberated refrigerant vapor entering boiler pipe 30 from the tube 27, and also vapor expelled from solution in the boiler pipe, ows upwardly into an air-cooled condenser 32 pro vided with a plurality of heat dissipating members or fins 33. Refrigerant vapor is liquefied in the condenser 32 and returns to the evaporator 17 through the conduit 18 to complete the refrigerating cycle. The conduit 18 is in heat exchange relation with the gas heat exchanger 19 at 18a to effect pre-cooling of liquid refrigerant flowing to the evaporator 17.

The weakened absorption liquid from which refrigerant vapor has been expelled, is conducted by gravity from boiler pipe 30 through a conduit 34, outer passage of the liquid heat exchanger 26 and conduit 23 into`A the upper part of the coil 22. The lower end of the condenser 32 is connected by a conduit 35 to the gas circuit, as to the upper part of absorber coil 22, for example, so that any non-condensable gas which may pass into the condenser, can flow to the gas circuit and not be trapped in the condenser.

As diagrammatically shown in Fig. 3, the evaporator 17 comprises pipe or conduit sections 17a and 17b which are connected by a bend 36, which for convenience may be referred to as evaporator elements. The evaporator elements 17a and 17b are connected in series relation with inert gas from conduit 24 owing through evaporator element 17a in the presence of and in parallel ow with liquid refrigerant which is introduced through conduit 18. Unevaporated liquid refrigerant is conducted from evaporator element 17a through the connecting bend 36 into the lower evaporator element 17b for ow in the latter in the presence of and in parallel flow with the inert gas.

Since the inert gas flows successively through the evaporator elements 17a and 17b, the gas in the upper evaporator element 17a contains a lesser amount of refrigerant vapor than the gas in the lower evaporator element 17b. The partial vapor pressure of the refrig-l erant is a gradient, so that the temperature of liquid refrigerant in the evaporator elements is also a gradient, the evaporating temperature of the liquid being lower in the upper evaporator element 17a which desirably constitutes the freezing portion of the evaporator 17.

In Figs. l and 2, in which parts corresponding to those shown in Fig. 3 are designated by the same reference numerals, the gas heat exchanger 19 extends into the storage space through a removable cover or closure 38 for an opening 39 in the rear insulated wall 40 of the cabinet 10. The cover 38, in which a body of heat insulating material 4 1 is retained, comprises a rectangular frame 42 formed of suitable material, such as wood, having inner'and outer plates 43 and 44, respectively. The inner plate 43 is depressed about its peripheral edge so that, whenthe cover 38 is positioned at :the opening, the greater part of the inner plate will be substantially flush with the inner shell 11, and the depressed peripheral edge thereof will bear against a gasket 45 adapted to be held against the inner shell 11. The outer plate 44, which is of greater area than the opening 3 9, is removably secured at 46 to the outer shell 12.

While in Fig. 3 the top cooling element 17a is diagrammatcally shown as a single pipe section, a practical form of this cooling element is illustrated in Figs. 1 and 2, in which a number of straight pipe sections and connecting bends are disposed in a single horizontal plane. In Figs. 1 and 2 the refrigerant fluid flowing through conduit 18 enters a straight pipe section which forms one arm of a U-shape coil 17a', the connecting bend 17a" of which is located at the forward part of the upper evaporator element 17a. The inert gas, which `is introduced into the U-shape coil 17a' through the conduit 24, ows in parallel with the refrigerant Huid through the spaced apart arms of the coil and then through a connecting bend at the rear of the top evaporator element into a third straight pipe section 1711" which is disposed betwen ,the spaced apart arms of the U.shape coil 17a. A s best seen in Fig. 2. the forward end of the third straight pipe section 17d" is connected by the bend 36 to one arm of a vertically disposed U-shaped coil which forms the bottom evaporator element 17b.

A plate 47 is arranged in good thermal exchange relation with the top evaporator element 17a. As best shown in Figs. l and 2, the plate 47 is notched at 48 at each lateral side thereof and bent to form C-shape edge portions or Agrooves which receive the spaced apart arms and front connecting bend of the U-shape coil 17a. A plurality of fins or heat transfer members 49 is xed to the U-shape coil forming the bottom evaporator element 17b. Before the evaporator 17 is positioned in the storage space 15, the plate 47, fins 49 and evaporator `elements 17a and 17b may be dipped into a body of molten zinc or provided with a suitable corrosion protecting agent in any other manner. In this way, the parts are protected against corrosion, and good heat conducting paths are provided between the plate 47 and the evaporator element 17a, and between the fins 49 and the evaporator element 17b.

The plate 47 forms a shelf which is adapted to receive one or more trays containing water to be frozen. The ns 49 xed to the bottom evaporator element 17b provide an extensive Vheat transfer surface for cooling air in the storage space 1 5. Hence, the lower temperature evaporator element 17a, to which the plate 47 is secured, is employed for making ice cubes and the like. The air in the storage space is preferably maintained at a desired low temperature which is above freezing, and this is accomplished by providing the relatively extensive heat .transfer surface for the higher temperature cooling element 17b.

Although not shown, `the evaporator 17 in Figs. 1 and 2 may be provided `with front and side baffle plates to conceal the evaporator or cooling unit from view. The side baille plate desirably is apertured to enable air in the storage space to circulate in thermal exchange relation with the bottom cooling element 17b and fins 49 fixed thereto, and the front battle plate is provided with an opening ,to 'gain access to the plate or freezing shelf 47.

I n Figs. ll and 2 it will be seen that the opening 39 in the vrear wall 40 ofthe cabinet 10 is of minimum size andonlysuiciently large to allow the evaporator elements 17a and 17b to pass therethrough when the refrigeration apparatus is mounted in position with respect to the cabinet 10. After the removable cover 38 is secured to the cabinet at 46, the baffle plates (not shown) for the evaporator 17, which are referred to above, may be fixed in position. As shown in Fig. l, a tray 50 which is supported on a shelf 51 may be provided beneath the evaporator 17.

In Figs. l and 2 the plate 47 actually forms the entire shelf area of the freezer section of the household refrigerator which has been described. While such a freezer section is relatively small, nevertheless it is compact and quite satisfactory in many instances where only one or two ice trays are required, and the need for storing frozen food, in addition to providing space for the tray or trays, is not important. This is especially true in refrigerator cabinets of small size having a storage space `or .compartment ranging from one to three cubic feet, for example. However,- it'is often desirable, even in refrigerator cabinets of small size, to provide adequate space for storing frozen food and producing additional quantities of ice, which cannot be accomplished by the evaporator element 17a and plate 47 fixed thereto.

In accordance with my invention, in order to provide either a small `or a larger size freezer section for household refrigerators when the same refrigeration unit or apparatus is employed in all of the cabinets, a larger size freezer section 52 Vis provided which may be removably secured at will to the low temperature cooling element 17a of the refrigeration apparatus. As shown in Figs. 4 and 5, the freezer section 52 h as a shelf area which is approximately twice as wide as that of the shelf or plate 47. The freezer section includes an inner liner 53 which is formed of a suitable metal having good heat conducting properties. The inner liner 53, which is of rectangular shape, defines the ceiling, bottom and lateral side walls of a freezer space 55. The bottom of the inner Yliner 53 is removably secured, as by screws 56, for example, to'the plate 47 which is fixed to the lower temperature cooling element 17a.

In order that vthe lower temperature cooling element 17a will function primarily to abstract heat from the freezer section 52, the latter is insulated and covers substantially the entire top surface of the plate 47. As shown in Figs. 4 and 5, the inner liner 53 is closed at the rear by a back wall 57. The freezer section 52 includesan'outer shell 58 which is arranged to be supported on the inner liner53 and insulated therefrom with any suitable insulating material 59.

The front wall of the outer shell 58 includes an imperforate section 58a which conceals the bottom cooling element 17b from view, an intermediate section having an opening for gaining access into the freezer space 55, and a top section having enlarged parts 58b to which an insulated door or Aclosure member 60 is hinged at 61. In addition, a vertical bathe plate 62 formed with openings 63 is provided at the side of the bottom evaporator element 17b which is removed from the right-hand lateral side wall of the refrigerator cabinet 10. The back wall 57 of the inner liner 53, the inner and outer walls of the closure member 60 and the walls of the outer shell 58 are formed of a suitable insulating material having poor heat conductivity, such as plastic sheeting, for example.

When Figs. l and 2 are compared with Figs. 3 and 4, it will b e seen that the freezer section 52 provided in Figs. 3 and 4 is considerably larger and approximately twice the width of `that `of the freezer section provided in Figs. l and 2 it being understood that the width of the freezer section in Figs. 1 and 2 Ais defined by the width v of the Vplate or vshelf 47, at the left-hand side of which a baille plate (not shown) may be arranged in any suitable manner, as explained above. Hence, even though a markedly larger freezer section 52 is obtained in Figs. l4 and 5 `than in Figs. l and `2, the opening 39 in the rear cabinet wall 40 and removable cover 38 therefor are still the same in both arrangements. This is highly advantageous when the freezer section 52 of Figs. 4 and 5 is employed, because it is desirable to keep the opening 39 in the thermally insulated wall 40 of minimum size in order to reduce the tendency for heat transfer into the storage space 15 at the cover 38 employed to close the wall opening.

When the freezer section 52 is employed, by reason of the good thermal connection of the right-hand part of the bottom of the inner liner to the plate or shelf 47 of the evaporator element 17a, cooling effect is effectively transmitted to frozen food packages `64 and the ice tray 65 resting on the bottom of the inner liner 53, as shown in Fig. 4. Since the bottom, lateral side walls and ceiling of the inner liner 53 may be formed of a single sheet of metal having good heat conductivity, cooling effect is also effectively transmitted along the side walls and ceiling to keep the upper part of the freezer space 55 at an extremely low freezing temperature. As explained above, the inner liner 53 is thermally segregated from the storage space 15 by the layer of insulation 59 and the outer shell 58, so that the inner liner will be eiciently utilized for freezing purposes rather than for an extensive heat transfer surface to cool air in the storage space. While the coil forming the upper cooling element 17a is not completely embedded in insulation, the gaps beneath the plate or shelf 47 and between the straight pipe sections of the upper cooling element 17a essentially form stagnant air spaces. Hence, the greater part of the cooling effect produced by the low temperature cooling element 17a is made available to the freezer section 52, and only an insignificant part is made available to effect cooling of air in storage space 15.

While a single embodiment of the invention has been shown and described, it will be apparent that various modifications and changes may be made without departing from the spirit and scope of the invention, as pointed out in the following claim.

What is claimed is:

In a refrigerator including a cabinet having thermally insulated walls including an inner liner defining a storage compartment, said liner having an opening and a closure therefor, absorption refrigeration apparatus including piping providing a circuit for inert gas comprising an evaporator located in the compartment, the piping for said evaporator being in the form of a coil having a first portion adapted to be operated at a low average or mean temperature and a second portion adapted to be operated at a higher average or mean temperature, said second portion being disposed below and vertically spaced from said first portion, a horizontally disposed plate which is in good thermal relation with the first portion of said coil for supporting one or more ice trays and the like, said horizontally disposed plate and first portion of said coil constituting a freezing section of said evaporator which is disposed in said storage compartment and removable therefrom through the opening in said liner, and structure for increasing the storage capacity -of said freezing section after said evaporator has been inserted into said compartment through the opening in said inner liner, said structure comprising a member, means providing a good heat conductive connection between said member and said freezing section, said member having a horizontally disposed surface extending between the lateral side walls of said inner liner which is markedly wider than the freezing section of said evaporator, a shell including said member which defines a low temperature space for storing matter to be frozen, said member forming the bottom of said shell, insulation about said shell to promote transfer of cooling effect from the freezing section of said evaporator to matter adapted to be stored in said space, said insulation having a gap at the region of said first portion of said evaporator to expose the latter to air in said storage space, heat transfer members fixed to the piping forming said lower second portion of said evaporator to promote transfer of cooling effect to air in said storage compartment, and said vertically spaced first and second portions of said evaporator having an air gap therebetween, said shell being wider than that of the opening in said liner when said member is in good heat conductive connection with said freezing section.

References Cited in the le of this patent UNITED STATES PATENTS

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