US2228144A

US2228144A - Refrigerating apparatus

Info

Publication number: US2228144A
Application number: US224786A
Authority: US
Inventors: Ralph K Miller
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1938-08-13
Filing date: 1938-08-13
Publication date: 1941-01-07
Anticipated expiration: 1958-01-07

Description

1941- R. K. MILLER 2,228, 4

REFRIGERATING APPARATUS Filed Aug. 13, 1938 2 Sheets-Sheet 1 2 Sheets-Shc et 2 TOR.

R. K. MILLER REFRIGERATING APPARATUS Filed Aug. 13, 1958 Jan. 7, 1941.

ATTQRNEYS Patented Jan. 7,1941

REFRIGERATING APPARATUS Ralph K. Miller, Dayton, Ohio, aasignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application August 13, 1938, Serial No. 224,786

11 Claims.

This invention relates to refrigerating apparatus and more particularly to household refrigerators. Household refrigerators have generally been provided with a single evaporating means located in the upper portion of a food storage compartment for cooling the food storage compartment by the circulation of air in contact with the walls of the evaporating means as well as for freezing ice in ice trays provided on shelves in the evaporator. This construction was economical and provided satisfactory ice freezing along with a somewhat better food preserving ability than the ice box which it had replaced. However, for certain foods such a refrigerator does not provide satisfactory food preservation because the humidty is not kept sufficiently high, the circulation of air is sometimes too rapid, and -the temperatures are often not kept sufliciently low to preserve foodstuffs in such a manner as to keep them in so a fresh condition both as to appearance and taste.

Attempts have been made to separate the refrigerator cabinet into two compartments and to provide separate refrigerating means for each compartment, but all such systems have been rela- 25 tively complicated and suiiiciently high in cost to prevent their sale in large quantities in competition with the older styles of household refrigerators. Such a style of two compartment refrigerators would require such extensive manufactur- 30 mg changes as to make the initial cost of manufacture too high.

It is therefore an object of my invention to provide a simplified, easily manufactured form of household refrigerator in which means are pro- 35 vided for satisfactorily preserving different types of foods, particularly fruits and vegetables.

It is another object of my invention to provide a household refrigerator which may be provided with a high humidity compartment employing 40 substantially all the parts of a conventional household refrigerator.

It is still another object of my invention to provide a household refrigerator having a plurality of compartments which may be adjustable in size 45 and which may be maintained at either different humidities or different temperatures, or both different temperatures and different humidities.

It is still another object of my invention to provide a simplified, easily manufactured form of 50 household refrigerator in whicl. a compartment is provided which is cooled by cooling the walls of the compartment.

It is a still further object of my invention to provide an improved means for cooling the outside 58 of the inner walls of the food compartment by a simple form of secondary refrigerant system made of plain tubing which may be applied to the walls after the inner walls are coated with porcelain.

It is still another object of my invention to provide a household refrigerator in which the primary 5 evaporator may be removed without disturbing the secondary refrigerant circuit. which it cools.

Further objects and advantages of the present invention will be apparent from the following. description, reference being had to the accompanyl0 ing drawings, whereina preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a perspective view looking at the rear of a household refrigerator cabinet having its 1 rear wall and insulation removed;

Fig. 2 is a fragmentary sectional view taken along the line 2-2 of Fig. 1;

Fig. 3 is a vertical sectional view through the refrigerator cabinet shown in Fig. 1; and

Fig. 4 is a bottom view of the evaporator shown in Figs. 1 and 3.

Briefly, I have shown a refrigerator cabinet of the household type in which the evaporator is suspended within the food compartment and the motor-compressor and condenser are located in the machine compartment beneath the food compartment. The evaporating means is generally of a b-shape type with shelves for ice trays and. clamped to the bottom of the evaporator is a U-shaped portion of a secondary refrigerating circuit formed of plain tubing which extends out through an aperture through the rear wall of the inner liner member, and extends around the bottom and the lower portions of the three sides of the inner liner member. This secondary circuit of tubing is clamped to the outside of the inner liner member and is fastened to it and held in placeby an asphaltic compound which is poured onto the secondary circuit and the adjacent portions of the inner liner in a molten condition.

A glass plate, provided with a rubber gasket seal around its edges, divides the food compartment into a lower highhumidity compartment and an upper low humidity compartment which contains and is cooleddirectly by the primary evaporating means.

Referring now to the drawings and more particularly to Figs. 1 and 3, there is shown a household refrigerator having the sheet metal outer walls 20 which extend continuously around the front and the sides of the cabinet and which are connected at the rear of the cabinet by another sheet metal member 22. The cabinet is also provided with an upper outer sheet metal member 24 above the food compartment and a lower outer sheet metal member 20 below the food compartment beneath which there is provided a machine compartment 28. The cabinet is provided with an ornamental top 30 which rests on top of the cabinet. Within the outer sheet metal walls there is provided a box-shaped inner liner member 32 having an open side facing the front and connected by a breaker strip 34 to the edges of a flanged door opening in the front portion of the outer sheet metal wall 20. This flanged opening is closed by an insulated cabinet door 36. The inner liner member 32 is preferably given a white porcelain coating on the inside and a black porcelain coating on the outside prior to the assembly of any parts thereon and prior to its insertion into the cabinet.

The inner linermember 32 encloses an upper food storage compartment 38 and a lower food storage compartment 40 which are divided by a glass plate 42 which is provided with a rubber metal gasket 44 which extends around the edges of the plate for providing a seal between the glass plate and the walls of the inner liner member 32 as well as between the plate and the inside face of the door 36. This gasket 44 has a curled portion 46 which extends into contact with the inner liner member 32 and upper and lower rubber portions 48 which extend around a metal channelshape frame member 50 and are turned into the space between the upper and lower faces of the glass plate 42 within the top and bottom portions of the channel-shaped frame member 50. This construction protects the glass from breakage and provides a simple and efficient seal between the two compartments. The glass provides a certain amount of insulation between the two compartments so that different temperatures as well as different humidities may be maintained in the different compartbents. If desired two spaced sheets of plate glass may be used instead of the single sheet 42 of plate glass in order to obtain a dividing plate of greater insulating properties.

The primary evaporator .52 is fastened to the top of the inner liner 32 but is slightly spaced therefrom by the spacers shown in Fig. 3. This primary evaporator 52 is generally of conventional construction and is provided with an upper refrigerated shelf 54 for ice trays as well as secondshelf 56 which is not refrigerated and which may be made removable if desired. The bottom 58 of the evaporator 52 also serves as an ice tray shelf. The bottom of this evaporator .52 is not altogether conventional, since it is provided with ducts 80 extending from front to rear on each side which connects to the downwardly. extending ducts to form a sort of header. These ducts 60 on either side of the bottom, are connected by ducts 612 and 64 which are somewhat in the form of a hairpin but which are connected at the rear of the evaporator between the ducts 60 and 64. There is a considerable portion 66 which is not provided with any refrigerant passages.

In order to provide suflicient refrigeration for the lower compartment 40 and to maintain high humidities therein I have provided a secondary refrigerant circuit formed entirely of plain copper tubing. The copper tubing in the secondary circuit for a 5 cu. ft. cabinet is about 28 to 30 feet long and the major portion is wound about the walls of the lower compartment 40. The copper tubing preferably has an outer diameter of 1; of an' inch and a wall thickness of about .035 of an inch. Preferably this secondary circuit operates at a higher temperature than the primary evaporator. For instance, if the primary evaporator.

is maintained at an average temperature of 20' I". it is desirable that this secondary refrigerant circuit operate at about 35 F. g

In order to obtain this temperature of the secondary circuit I have provided a condensing portion 68 of the secondary circuit which is formed so as to fit the space 56 at the bottom of the evaporator between the ducts 88 and 64 This condensing portion 58 includes loops I0 and 12 which are located oneach side of the duct 84 and are so formed that the tubing extends along the ducts on each side towards the front of the evaporator and then extends along the duct 84.. This secondary system, generally designated by the reference character I4, is altogether independent physically from the primary evaporator 52 except that the portion 68 is clamped to the bottom of the evaporator 52 by four removable clamps all designated by the reference character I6 which are held in place by means of nuts I8 to the bottom of the evaporator. These nuts are threaded on studs or bolts which extend through the nonrefrigerated portion 66 upon the bottom of the evaporator. frigerant circuit I4 in contact with the evaporating means is about 42 inches or 44 inches long for this size of refrigerator.

The inlet 80 of the condensing portion 68 is slightly higher than the outlet 82 in order to provide a fall in between the entrance and exit of the condensing portion 68. From the outlet 82 the secondary circuit, in the form of tubing, extends downwardly at an angle of 45 across the back of the cabinet forming the down portion 84 to the corner of the inner liner and thence extends downwardly to the bottom of the inner liner forming the down portion 88. At the bottom of the inner liner, the secondary circuit has a bottom portion 88 which extends over to. a long vertical clamp having a portion extending beneath the bottom of the inner liner member 32 for clamping the portion 88 to the bottom of the inner liner. The tubing forming the secondary circuit then extends to another clamp 92 upon the opposite side of the cabinet which also has a portion for engaging a loop of. the bottom portion 88 of the secondary circuit. The bottom portion is provided with another loopwhich is clamped by a second clamp 94 upon the side of the inner liner where the clamp is located.

The secondary tubing then extends along the front edge of the inner liner and is turned upwardly and held by the fourth clamp 95 located upon the same side of the inner liner as clamp 92. The secondary circuit then extends entirely around the sides and back of the cabinet in the form of a loop 98 which is held on the sides by the four clamps. The secondary circuit then extends to form a loop I02 upon the opposite side of the cabinet which is also held by the clamps 90 and 94 after which the tube extends upwardly to form a goose-neck trap I04 which insures a unidirectional flow ofrefrigerant within the secondary circuit and makes it necessary that only gas issue from the portion I02. The secondary circuit is provided with a charging tube I06 upon the 45 portion 84 through which the secondary circuit is charged with a suitable amount of volatile liquid such as difluorodichloroethane of which preferably about 15 ounces is used. When the charging is completed, the charging tube is pinched off and sealed.

The size of the two

compartments

88 and 40 may be varied by raising or lowering the divid- The portion of the secondary re- 86 serve as backing members for fastening the shelf guides in place as well as for supporting the secondary circuit. The shelf guides I44 and I46 are provided above the shelf guides I40 while shelf guides I48 and I50 are provided beneath the shelf guide I40. The glass plate 42 may be placed upon any one of the shelf guides in order to vary the size of the two compartments. These last two shelf guides I48 and I50 are connected by screws extending through. the clamping members and the wall of the inner liner into the shelf guides in a manner similar to that for the shelf guide I40. The shelf guide I48 preferably receives a sliding shelf but it may also be used to support the glass plate 42 when only a small high humidity compartment is desired. The lower shelf guide I50 is intended for supporting the shelf containing a pair of ventilated vegetable drawers,

such as are shown and described'in the Braeutiof the inner liner member and so provides better heat transfer between the secondary circuit and the inner liner member as well as holds the secondary refrigerant circuit in place.

The primary evaporator may readily be removed from the cabinet without disturbing the secondary circuit. This is done by removing the clamps i The space between the inner liner member 32 and the outer sheet metal walls is preferably filled with some suitable insulating material I56, such as glass wool. Preferably the portion of the inner liner provided with the secondary refrigerant circuit is coated with heavy wrapping paper prior to its insertion in the cabinet in order to permit easy insertion of the inner liner into the cabinet without disturbing the insulation which is preferably packed in place prior to the insertion of the inner liner. The inner liner member 32 is readily removable through the door opening of the cabinet by removing the screws which fasten the breaker strip to the flange surrounding the door opening. This also requires the removal of the clamps I6 which clamp the of the evaporating means.

portion 88 of the secondary circuit to the bottom Thus merely by unfastening the evaporator from the top wall of the inner liner and by removing the clamps 15 as well as plates at the rear of the evaporator the inner liner member may be removed from the cabinet through the door opening while the primary evaporator 52 may be removed through the opening in the rear wall of the cabinet.

v With this construction it is not necessary to use an inert gas in the secondary refrigerant system in order .to maintain a temperature differential between the primary evaporator and the secondary evaporator. This is taken care of by limiting the amount of heat transfer between the primary evaporator and the condensing portion 68 of the secondary refrigerant system. However, if desired better heat transfer can be ob- ,tained by providing greater contact area between the condensing portion 68 andthe bottom of the evaporator, and with such an arrangement an inert gas may be used in the secondary system in order to maintain the desired temperature differential between theprimary evaporator and the secondary circuit. Preferably the secondary circuit is always maintained at a temperature above freezing. The primary evaporator normally operates below freezing temperatures in order to freeze ice cubes. Thus this arrangement, the adjacent portions of three sides and the bottom of the inner liner member 32 are cooled to a temperature of about 36 F. Because of this large amount of cooling surface provided for the lower compartment 40, the secondary circuit may operate at a relatively high temperature and yet maintain a low temperature in the compartment 40. The high temperature of the cooling surface makes possible a high humidity.

The inner liner member 32 is provided with an opening H0 in its rear wall adjacent the rear of the evaporator. This opening is provided with a curled edge which supports a set of plates I I2 and II4 which close the opening III). A rubber gasket is provided between the edges of the plate and the edges of the opening H0 and a rubber gasket is also provided between the adjacent edges of the plates H2 and H4. Between the adjacent edges of the plates H2 and H4 there is provided an upper aperture sealed by a rubber grommet IIS through which the liquid supply line I I8 and the liquid return line I20 extend to the evaporating means from the motor-compressor-condenser unit provided in the machine compartment.

The motor-compressor condenser unit comprises a sealed motor-compressor unit I20 which compresses the refrigerant and forwards the compressed refrigerant to a finned natural draft condenser I22 which has its lower end connected to the liquid supply conduit I I8 while the return conduit I20 is connected to the inlet of the motorcompressor unit I20. The supply and return conduits H8 and I20 are preferably soldered together a considerable portion of the distance between the motor-compressor-condenser unit and the evaporator to provide a transfer of heat from the supply conduit to the return conduit. The liquid supply conduit I I8 is preferably formed of capillary tubing and connects to a restrictor I24 located in the food compartment 38 for controlling the feeding of the liquid refrigerant into the primary evaporator.

The operation of the refrigerating system is controlled by a switch I25 which is located within the confines of the evaporator 52 near the top of the cabinet. This switch I26 has a thermostat bulb I23 which is clamped to the side wall of the evaporator 32 just beneath the upper shelf 64. The control switch'l26 is preferably of some form of dual control responsive not only to the temperature of the evaporating means through the medium of the bulb I28 but also responsive to the temperature of the compartment within which the switch mechanism I26 is located. Several examples of such a switch is shown in the Grooms Patent No. 2,101,498, patented Dec. '7, 1937. Such a control controls the operation of the refrigerating apparatus so as to not only maintain the temperature of the evaporating means within certain limits but also tends to maintain the temperature of the compartment 32 within certain limits.

In order to prevent the compartment 32 from becoming too cold and yet providing adequate refrigeration for the lower compartment 40 and for freezing ice, the primary evaporator 52 is provided with shields I30 and I32 located upon opposite sides of the primary evaporator 32 and fastened to the top of the inner liner in a manner somewhat similar to the evaporating means 52. These shields are held spaced from the evaporating means by Bakelite" spacers I3l. The evaporating means is also provided with a rear zclosure plate I33 and'a front door I38 for further reducing the surface available for cooling the compartment 38.

It will be noted that my two compartment refrigerator diifers only slightly from the conventional refrigerator in its general construction so that the economy of mass production of this general type may be used for this two compartment refrigerator. In general only the secondary refrigerant circuit, the glass plate 42 and the shielding of the evaporator means have been added to the conventional refrigerator. This form of refrigerator makes it possible to provide a cold atmosphere having relatively high humidity in the compartment 40 and a considerably drier atmosphere in the compartment 33. The cooling of the compartment 40 through the secondary refrigerant circuit which surrounds the walls of the inner liner particularly aids in maintaining a high humidity in this compartment and prevents dehydration because the heat leaking through the insulation is withdrawn by the secondary circuit before it reaches the air in the compartment Ill. The rate of air circulation within the two compartments is also less than has been customary.

I The front lower lip of. the inner liner member is provided with a ridge I60 for preventing any moisture which might collect on the bottom of the inner liner from running out the door of the'cabinet when the door is open. It will be noted that when the door 36 is open access is readily had both to the upper compartment 38 and the lower compartment 40. The glass plate 42 assures ready and complete visibility to the lower compartment 40. Thus I have provided a two compartment refrigeratorwhich is simple, practical, economical and very effective for the preserving of foods, because of the cool moist compartment ll.

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

What is claimed is as follows:

1. Refrigerating apparatus including a cabinet provided with a metal inner liner member, 9.

refrigerant evaporating means entirely within said inner liner member, a portion of said inner liner member being provided with means forming a secondary refrigerant circuit, said means forming a secondary refrigerant circuit having a cloned metal, walled containing portion extending forwardly from the rear wall of the inner liner member, means for clamping said metal walled containing portion to a portion of the surface of the evaporating means, and a movable partition within said inner liner separating the evaporating means and the adjacentinterior of the inner liner from the interior of said portion of said inner liner provided with the secondary circuit.

2. Refrigerating apparatus including a cabinet provided .with a metal inner liner member, an evaporating means entirely within said inner liner member, means forming a secondary refrigerant I circuit including tubing having portions extending around a portion of the outside of said inner liner member, means for clamping and holding said tubing in intimate thermalcontact with the exterior-of said inner liner member, said means forming a secondary circuit having another portion extending into the interior of said inner liner into intimate thermal contact with said evaporating means, and a movable partition within secondary refrigerant circuit having a portion in heat exchange relation with the outside of the portion of the inner liner member which surrounds the other compartment, said means forming a secondary refrigerant circuit having another portion in heat exchange relation with said refrigerant evaporator, said dividing wall being movable to change the size of .said compartments.

4. Refrigerating apparatus including a cabinet provided with a single unitary inner liner member, a movable dividing wall dividing the interior of said inner liner into two compartments, a refrigerant evaporator located in one of said compartments in'said inner liner member spaced from and outside the plane of the dividing wall for preventing direct contact with the atmosphere in the other compartment, means forming a secondary refrigerant circuit having a portion in heat exchange relation with the outside of the portion of the inner liner member which surrounds the other compartment, said means forming a secondary refrigerant circuit having: another portion in heat exchange relation with said refrigerant evaporator, said dividing wall being transparent.

5. Refrigerating apparatus including a cabinet containing an inner liner member, a refrigerant evaporator within said inner liner member, said inner liner member being provided with an aperture adjacent said evaporator, tubing containing a secondary refrigerant having a portion in contact with the outer surface of said inner liner member, said tubing extending through said aperture into the interior of said inner liner member into contact with a surface of said evaporator,

and means for clamping said tubing to the outer surface of said inner liner member.

6. Refrigerating apparatus including a cabinet containing an inner liner member, a refrigerant evaporator within said inner liner member, said inner liner member being provided with an aperture adjacent said evaporator, tubing containing a secondary refrigerant having a portion in contact with the outer surface of said inner liner member, said tubing extending through said aperture into the interior of said inner liner member into contact with a surface of said evaporator, and means for clamping said tubing to said surface of said evaporating means.

7. Refrigerating apparatus including a cabinet,

a single unitary inner liner member within the cabinet, an evaporator within the cabinet, said inner liner member being provided with a large aperture adjacent the rear of the evaporator to permit removal of the evaporator, said inner liner memher being provided with means forming a secondary refrigerant circuit, said means forming a secondary refrigerant circuit being provided with a portion extending through said large aperture into heat exchange relation with the evaporator.

8. Refrigerating apparatus including a cabinet provided with box-shaped walls enclosing a compartment to be kept cool, means for cooling said compartment with diminished convection currents, high humidity and reduced dehydration comprising refrigerating means for reducing temperatures of the inner faces of the bottom and three distinct vertical wall portions of said boxshaped walls below the temperature of the atmosphere within the compartment but above water freezing temperatures. R

9. Refrigerating apparatus including a cabinet provided with box-shaped walls enclosing a compartment to be kept cool, means for cooling said 40 compartment with diminished convection ourrents, high humidity and reduced dehydration comprising refrigerating means for reducing temperatures of the inner faces of the bottom and three distinct vertical wall portions of said boxshaped walls below the temperature of the atmosphere within the compartment but above water freezing temperatures, said refrigerating means including means for first feeding a cooling medium into heat exchange relationship with said bottom wall portion and thence into heat exchange relationship with said three distinct vertical wall portions.

10. Refrigerating apparatusincluding a cabinet provided with box-shaped walls enclosing a compartment to be cooled, a movable dividing wall means dividing said compartment into a plurality of sub-compartments, a primary refrigerating means spaced from and outside the plane of said movable means for creating water freezing temperatures in one of said sub-compartment's and means for cooling a second sub-compartment with diminished convection currents, high humidity, and reduced dehydration comprising means including a secondary circuit cooling means connected in heat transfer relationship with said primary refrigerating means for cooling the inner faces of the bottom and three distinct vertical wall portions of said second sub-compartment to temperatures below the temperature of the atmosphere of said second compartment but above water freezing temperatures.

11. The method of producing refrigeration and diminishing convection currents, increasing humidity and reducing dehydration within a metallined storage compartment which comprises cooling the bottom and three distinct vertical wall sections of said metal lining by a cooling medium maintained above water freezing temperatures.

RALPH x. MILLER.