US3111817A

US3111817A - Multiple temperature refrigerator

Info

Publication number: US3111817A
Application number: US144377A
Authority: US
Inventors: Jr Douglas A Solley
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1961-10-11
Filing date: 1961-10-11
Publication date: 1963-11-26
Anticipated expiration: 1980-11-26
Also published as: GB995892A

Description

Nov. 26, 1963 D. A. SOLLEY, JR

MULTIPLE TEMPERATURE REFRIGERATOR 3 Sheets-Sheet 1 Filed Oct. 11, 1961 INVENTOR. DOUGLAs A. SOLkEY J'R. "W

HlS ATTORNEY Nov. 26, 1963 D. A. SOLLEY, JR 3,111,817

MULTIPLE TEMPERATURE REFRIGERATOR Filed Oct. 11, 1961 s Sheets-Sheet 2 jillflltillf INVEN TOR.

DOUGLAS A. SOLLEY TR.

H \5 ATTORNEY Nov. 26, 1963 D. A. SOLLEY, JR 3,111,817

MULTIPLE TEMPERATURE REFRIGERATOR Filed Oct. 11, 1961 3 Sheets-Sheet 3 F'lG.3

INV EN TOR.

F" G 4 DOUGLAS A. SOLLEY TR.

HlS ATTORNEY United States Patent 3,111,817 MULTIPLE TEMPERATURE REFRIGERATOR Douglas A. 'Solley, 'Jr.,.Fern Creek, Ky, assrgnor-toGenera'l Electric Company, a corporation of New York Filed Oct. 11, 1961, Ser. No. 144,377 3 Claims. (Cl. 62-283) The present invention relates to arefrigeratorcomprising two -or more compartments maintained at different 'temperatures by means of separate air streams circulated 'to the'compartments from a single evaporator unit. his more particularly concerned with an improved evaporator arrangement for refrigerating .such a refrigerator.

In multiple temperature refrigerators, there is normally proved a freezer compartment operating at below freezing temperatures for the storage of frozen foods and afresh food compartment operating at above freezing temperatures for the storage of unfrozen or fresh foods. When a single evaporator is employed to maintain the desired temperatures within both of the compartments, the evap- -'orator is operated at a temperature a few degrees below that'desired in the freezer compartment. If a single fan is employed to circulate the refrigerated air through both compartments, the return air streams from the compartments are generally mixed or intermingled as they are brought into heat exchange relationship with the evaporator while the cooled air flowing from the evaporator is divided and the divided streams so proportioned as to maintain the desired freezing temperature in the freezer compartment and the desired above freezing temperature in'the fresh foodcompartment. In the known systems of this type, the entire evaporator :is exposed to the high moisture content of the air flowing from the higher temperature fresh food storage compartment. As a result, the surfaces thereof rather quickly become covered with an insulating layer of frost'with a resultant deterioration in the heat transfer rate between the evaporator and the air stream. Since the desired freezer temperatures are generally relatively close to the normal evaporator temperatures, frequent defrosting of the evaporator is essen- .tial to maintain the required evaporator heat transfer rate.

It is a primary object of the present invention to provide-a new and improved multiple temperature refrigerator including a single evaporator unit and fan means for circulating air over the evaporator and through the various compartments of the refrigerator, the evaporator unit being so designed that the desired low temperatures within the freezing compartment can be maintained for .a relatively prolonged period of time without requiring defrosting of the evaporator unit.

Another object of the present invention is to provide in a refrigerator, an improved forced air cooling system including a single evaporator for cooling the air circulated .through all of the compartments which evaporator is so constructed and arranged that the moisture contained in the return air from the fresh food or higher temperature compartment is prevented from affecting the heat transfer rateof the unit as a whole.

A more specific object of the present invention is to provide in a household refrigerator, an improved evaporator unit for the forced air cooling of two or more compartments operating atdifferent temperatures which evaporator is designed to limit the deposition of frost to certain portions of the evaporator in such a manner that the frost load of the air flowing from :the high temperature compartment will not adversely affect the desired cooling of the freezer or low temperature compartment.

Further obiects and advantages of the present invention will become apparent from the following description and the features of novelty which characterize the invention 3,111,817 Patented Nov. 26, 1963 "ice will be pointed out with particularity in the claims annexed to and forming part of this specification.

In accordance with the present invention, there is provided a household refrigerator comprising a fresh food compartment operated at above freezing temperatures and a freezer compartment operating at temperatures below freezing. In order to refrigerate both of the compartments, there is provided an evaporator unit disposed outside the storage compartments and including a housing and a vertically extending partition within the housing which divides the housing into two chambers. The partition has a bottom portion thereof spaced from an adjacent wall of the housing to form an air passage connecting the two chambers. An evaporator contained within the housing includes a first section disposed in the lower portion of one of the chambers and a second section disposed in the lower portion of the second chamber. Both of the evaporator sections include vertical fins substantially bridging the space between the front and rear walls of the housing and the fins on the first section of the evaporator spaced a greater-distance apart than the fins on the second section. Air'is refrigerated by heat exchange with the evaporator and is circulated to the storage compartments of the refrigerator by means of a single fan and sup- .ply duct means in which the fan inlet is connected to the upper portion of the second chamber, that is the section containing the closely spaced fins. Return air from the freezer compartment is conducted into the second chamber near the bottom thereof so that it passes only over the second section of the evaporator in passing to the fan. Air from the fresh 'food compartment is introduced into the first chamber of the housing above that portion of the evaporator containing the more widely spaced fins so that its higher initial moisture content is substantially lowered as the air flows downwardly through this section of the evaporator. The relatively dehumidified air then flows through the passage formed by the partition and into the second chamber where it is further cooled as it mingles with the return air from the freezer compartment and flows upwardly to the fan between the more closely spaced fins of the evaporator.

For a better understanding of the invention, reference may be had to the accompanying drawing in which:

FIGURE 1 is a front elevation, with the closure members removed, of a refrigerator cabinet including an embodiment of the present invention;

FIGURE 2 is a vertical sectional view taken generally along the line 2--2 of FIGURE '1;

FIGURE 3 is an enlarged rear view of the evaporator unit taken generally along line 33 of FIGURE 4; and

FIGURE 4 is a horizontal sectional view taken generally along the line 4-4 of FIGURE 3.

With reference to the drawing and particularly FIG- 1 and 2 thereof, there is shown an insulated refnger-ator cabinet comprising an upper freezer compartment I intended to operate at a temperature below freezmg and a lower fresh food compartment 2 adapted to operate at an above freezing temperatureof about 35-40 F. An evaporator structure 3 provides the refrigeration required for both compartments. In the illustrated embodiment of the invention, this evaporator structure 3 is shown as being disposed in the insulated wall area immediately behind the rear wall 1 of the freezer compartment 1 although it is to be understood that it could 3 in heat exchange relationship with the evaporator is dis charged from the fan 7 through a plenum or hollow duct 11 above the freezer compartment 1 and into the top of that compartment through a plurality of slots 12. In addition to the fan discharge 14 which directs air from the fan into the duct 11, the fan is provided with a second discharge 15 from which air, cooled by the evaporator, is conducted to the fresh food compartment 2 through duct 16 and an opening 1'7 adjacent the bottom portion of the fresh food compartment which may be provided with a control damper 18 for regulating the supply of refrigerated air to that compartment. Air returning to the evaporator unit 3 from the compartment 2 leaves that compartment through an opening 19 and by means of the return air duct 21 is introduced into the evaporator housing 6 through an air return or inlet opening 20.

In accordance with the present invention, the evaporator unit 3 is so designed that frost formation resulting from the relatively high moisture content of the return air from the fresh food compartment will be limited to selected areas of the evaporator in such a manner that the unit will operate at or near its maximum heat transfer rate without frequent defrosting of the evaporator.

To this end, the evaporator unit, as is shown in greater details in FIGURES 3 and 4 of the drawing includes a partition 23 which divides the unit housing 6 into two chambers. One chamber 24 is at one end of the housing and the other chamber 25 is at the other end. The partition 23, which is in contact with the top wall and front and rear walls of the housing 6, terminates short of the bottom wall 27 to provide a passage 28 which is the only communication within the housing between the two

chambers

24 and 25. The air return inlet 20 for the fresh food compartment air is at the upper portion of the chamber 24 while the fan 7 is connected to the upper portion of the chamber 25.

The evaporator unit '5 is disposed in the lower portions of the two chambers below inlet 20 and the outlet to the fan 7. In the illustrated embodiment, the evaporator comprises a plurality of horizontal refrigerant tubes and a plurality of vertically extending fins with the tubes extending through the partition 23 dividing the evaporator into two sections respectively disposed in the lower portions of the

chambers

24 and 25. However, it is to be understood that the invention is not limited to this particular construction but includes any evaporator structure in which the evaporator includes a first section 30 disposed in the lower portion of the chamber 24 and having a plurality of fins 31 extending vertically in contact with the front and rear walls of the housing 6 and a second section 32 disposed in the lower portion of the chamber 25 and including vertically extending fins 33 substantially engaging the front and rear walls of the housing 6. The lower ends of both of the

sections

30 and 32 are spaced from the bottom Wall 27 of the housing 6 to permit air flow from all portions of one section of the evaporator to all portions of the other through the passage 28. A refrigerant accumulator 3 5 is arranged in the upper portion of the chamber 24 above the evaporator section 30 and substantially opposite the air inlet or return opening 20 communicating with that chamber. This accumulator 35 forms part of a usual refrigerating system including a compressor 37, a condenser 38, suitable flow restricting means (not shown), the evaporator 35 and the accumulator in closed series flow connection.

The air return opening 9 connecting the freezer compartment 1 with the evaporator unit is at the lower portion of the chamber 25 adjacent the bottom edge of the evaporator section 32 so that upon operation of the fan 7 air withdrawn from the freezer compartment 11 flows upwardly between the fins 33 and is discharged by the fan 7 through the ducts 1 4 and 16. The return air from the fresh food compartment 2 first enters the top portion of chamber 24 through the air inlet 20 above the 4 evaporator section 30 and the primary purpose of the partition 23 is to direct the tlow of air from the fresh food compartment 3 through the evaporator section- 30 before it comes in contact with the section 32 or in other Words before it becomes intermingled with the relatively low humidity return air from the freezer compartment 1. By means of the partition 23, the return air from the fresh food compartment entering the housing through the inlet 20 is caused to flow downwardly between the fins 31 on the evaporator section 30 so that this entire evaporator section is contacted by this relatively moist air for the removal of the major portion of the moisture content thereof before it passes through the passageway 28 beneath the partition 23. Some of the frost load in this fresh food compartment return air also collects on the accumulator 35 which is normally the coldest part of the refrigerating system and which is therefore preferably positioned directly in the path of the air entering the chamber 24 so that it will not only aid in dehumidifying that air but will also be warmed by it to evaporate the liquid refrigerant collecting in the accumulator.

From the drawing, it will be noted that there is a substantial difference in the fin spacing on the two

sections

30 and 32 of the evaporator. The wider spacing of the fins 3 1 on section 30 is employed to allow the fresh food compartment air to form a frost layer of substantial thickness on the surfaces of the evaporator section 30 before there is any substantial restriction of the air flow through the section. The narrower spacing of fins 33 on section 32 provides a good heat transfer rate between the evaporator section 32 and the air streams from both compartments in order to obtain maximum efficiency in the operation of the unit. To this end, the fins 31 may for example be spaced about 1 inch apart as compared with a A inch spacing of the fins 33 on the evaporator section 3 2.

A further advantage of the evaporator unit of the present invention is that any excess moisture remaining in the air flowing through the passageway 28 and into the chamber 25 will, by reason of the construction and resultant air flow paths through the evaporator section 32, be caused to condense on only the first few fins 33 adjacent the partition 23 thereby leaving the remaining portions of the evaporator section 32 substantially free of frost to operate at maximum heat transfer efficiency. Although the fresh food compartment air as it passes in heat exchange relationship with the evaporator section 30 becomes cooled to a temperature relatively close to that of the freezer air returning to the evaporator unit through the slot 9, there may be some moisture remaining in the air which will condense as the air makes further contact with the cooled evaporator surfaces. By positioning the inlet to the fan 7 in the upper portion of the chamber 25 above the evaporator and by providing the air return opening 9 from the freezer compartment in the form of a slot substantially the full width of the evaporator section 32 so that most of this evaporator section is exposed to the air flowing from the freezer compartment, the fresh food compartment air flowing issuing from the passage 28 will tend to follow a path of least resistance and flow upwardly through the spaces between the first few fins next to the partition 23. Any moisture remaining in this air will deposit on these fins leaving the remaining portions of the evaporator section 32 free of any but the normal frost load resulting from the moisture contained in the freezer compartment air flowing into the chamber 25 through the 'passage 9. As the first few fins in the chamber 25 become coated with frost, the fresh food air stream will be diverted by the accumulated frost along the passage beneath the evaporator section 32 and upward between the next few fin passages. In no case however is the moisure load of the fresh food air distributed uniformly over the entire freezer section 32 of the evaporator, to

decrease its heat transfer coefficient. .In other words, one end of slot '9 is spaced from the partition '23 a distance such that the spaces between the fins disposed between the partition and the slot '9 are sufficient to accommodate most of the air flowing through the passage 23. This air flow tends to be restricted more -or less to this portion of the evaporator section 32 by the rela- "tively :larger quantity of air normally drawn by the fan 7 .into the chamber 25 through the air return slot Orpassage 9. The two air streams flowing from the two compartments for the first time in the space above :section 32 as they are drawn into the fan for recirculation.

It will be understood of course that even though the evaporator unit of the present invention is designed to accommodate a substantial frost load, it will be necessary periodically to remove the accumulated frost to avoid either a complete blocking of the air paths between the fins 31 on the evaporator section 30 or blocking of a substantial number of the passageways between the fins 33 on the section 32. Any suitable defrost means may be provided for defrost purposes and for that reason no specific means has been shown. By way of example, suitable electrical heating means may be used to warm the evaporator unit including the accumulator to defrosting temperatures or means may be provided for circulating hot refrigerant gas through or in heat exchange relationship with the evaporator tubing and the accumu lator 35 I From the above description it will be seen that there has been provided an improved evaporator unit by means of which one fan and one evaporator can be employed to effectively cool, by forced air circulation, both the fresh food and freezer compartments of a refrigerator. The unit is so designed that it is possible to use relatively tightly spaced and extended heat transfer surfaces, that is the fins 33, on the portion of the evaporator which finally cools the air flowing to both compartments to maintain the freezer compartment at the desired freezing temperatures while at the same time maintaining the highly eflicient operation of the evaporator by a controlled deposition of the main frost load from the fresh food compartment air before that air contacts the evaporator section 32.

While there has been shown and described a particular embodiment of the present invention, it is to be understood that the invention is not limited thereto and it is intended 'by the appended claims to cover all modifications Within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A household refrigerator comprising a fresh food compartment operated at above-freezing temperatures, a freezer compartment operated at below-freezing temperatures, means for refrigerating said compartments comprising an evaporator unit including a housing having front, rear, top and bottom walls, a partition within said housing dividing said housing into first and second chambers, said partition having a bottom portion thereof spaced from the bottom wall of said housing to form a passage connecting said chambers, an evaporator comprising a first section disposed in the lower portion of said first chamber and a second section disposed in the lower portion of said second chamber, both of said sections including vertical fins substantially bridging the space between the front and rear housing Walls with the fins on said first section spaced a greater distance from one another than the fins on said second section, said sections being spaced from the top wall of said housing to provide a space in the upper portion of each chamber between the evaporator section contained therein and the top wall of said housing, means for Withdrawing cooled air from the upper portion of said second chamber and conducting separate air streams to said fresh food and freezer compartments, a first air return means connecting said fresh food compartment only with the upper portion .of said first chamber and a second air return means connecting said freezer compartment with the lower portion of said second chamber whereby the air streams returning from the freezer and fresh food compartments are kept separate until after the moisture content of the air stream returning from the fresh food compartment is substantially lowered by contact with said first-evaporator section.

,2. A household refrigerator comprising a fresh food compartment operated at above-freezing temperatures, ."a freezer compartment operated at below-freezing temperatures, means for refrigerating said compartments comprising an evaporator unit including a housing having front, rear, top and bottom walls, a vertically extending partition Within said housing dividing said housing into first and second chambers, said partition having a bottom portion thereof spaced from the bottom wall of said housing to form a passage interconnecting said chambers, an evaporator disposed within the lower portion of said housing and comprising a first section disposed in said first chamber and a second section disposed in said second chamber, both of said sections including vertical fins substantially bridging the space between the front and rear housing walls with the fins on said first section spaced a greater distance from one another than the fins on said second section, said sections being of a height less than the height of said chambers to provide a space in the upper portion of each chamber between the evaporator section contained therein and the top wall of said housing, means for withdrawing cooled air from the upper portion of said second chamber and conducting separate air streams to both said fresh food and freezer compartments, a first air inlet connecting said fresh food compartment only with the upper portion of said first chamber whereby the moisture content of the air from the fresh food compartment is substantially lowered by condensation thereof on said first evaporator section before that air passes into said second chamber, and a second air inlet connecting said freezer compartment only with the lower portion of said second chamber, said second air inlet comprising a horizontal slot in the front wall of said housing of a width substantially that of said second evaporator section.

3. A household refrigerator comprising a fresh food compartment operated at above-freezing temperatures, a freezer compartment operated at below-freezing temperatures, means for refrigerating said compartments comprising an evaporator unit located outside of said compartments, said unit including a housing having front, rear, top, and bottom walls, a vertically extending partition within said housing dividing said housing into first and second chambers, said partition having a bottom portion thereof spaced from the bottom wall of said housing to form a passage connecting said chambers, an evaporator disposed Within the lower portion of said housing and comprising a first section disposed in said first chamber and a second section disposed in said second chamber, both of said sections including vertical fins substantially bridging the space between the front and rear housing walls with the fins on said first section spaced a greater distance from one another than the fins on said second section, said sections being of a height less than the height of said chambers to provide a space in each chamber between the evaporator section contained therein and the top wall of said housing, forced air circulating means including an air outlet in the rear wall of said second chamber for withdrawing cooled air from the upper portion of said second chamber and conducting separate air streams to said fresh food and freezer compartments, a first air return means connecting said fresh food compartment only with the upper portion of said first chamber and a second air return means comprising an elongated horizontal opening in the front wall of said housing connecting said freezer compartment with the lower portion of said second chamber, said opening terminating at one end a distance from said partition such that air from said fresh food compartment flowing through said passage after contact with said evaporator section will follow a path upwardly between the fins disposed between said partition and said opening whereby the deposition of frost on said second section due to any moisture remaining in the air flowing through said passage will be limited to these fins.

References Cited in the file of this patent UNITED STATES PATENTS Bishop June 9, Murphy Dec. 9, Detwiler Mar. 22, 'Hargrave Apr. 19, Hubacker Feb. 13, Mann Apr. 3, Solley Aug. 28,

Mann Aug. 28,

Claims

1. A HOUSEHOLD REFRIGERATOR COMPRISING A FRESH FOOD COMPARTMENT OPERATED AT ABOVE-FREEZING TEMPERATURES, A FREEZER COMPARTMENT OPERATED AT BELOW-FREEZING TEMPERATURES, MEANS FOR REFRIGERATING SAID COMPARTMENTS COMPRISING AN EVAPORATOR UNIT INCLUDING A HOUSING HAVING FRONT, REAR, TOP AND BOTTOM WALLS, A PARTITION WITHIN SAID HOUSING DIVIDING SAID HOUSING INTO FIRST AND SECOND CHAMBERS, SAID PARTITION HAVING A BOTTOM PORTION THEREOF SPACED FROM THE BOTTOM WALL OF SAID HOUSING TO FORM A PASSAGE CONNECTING SAID CHAMBERS, AN EVAPORATOR COMPRISING A FIRST SECTION DISPOSED IN THE LOWER PORTION OF SAID FIRST CHAMBER AND A SECOND SECTION DISPOSED IN THE LOWER PORTION OF SAID SECOND CHAMBER, BOTH OF SAID SECTIONS INCLUDING VERTICAL FINS SUBSTANTIALLY BRIDGING THE SPACE BETWEEN THE FRONT AND REAR HOUSING WALLS WITH THE FINS ON SAID FIRST SECTION SPACED A GREATER DISTANCE FROM ONE ANOTHER THAN THE FINS ON SAID SECOND SECTION, SAID SECTIONS BEING SPACED FROM THE TOP WALL OF SAID HOUSING TO PROVIDE A SPACE IN THE UPPER PORTION OF EACH CHAMBER BETWEEN THE EVAPORATOR SECTION CONTAINED THEREIN AND THE TOP WALL OF SAID HOUSING, MEANS FOR WITHDRAWING COOLED AIR FROM THE UPPER PORTION OF SAID SECOND CHAMBER AND CONDUCTING SEPARATE AIR STREAMS TO SAID FRESH FOOD AND FREEZER COMPARTMENTS, A FIRST AIR RETURN MEANS CONNECTING SAID FRESH FOOD COMPARTMENT ONLY WITH THE UPPER PORTION OF SAID FIRST CHAMBER AND A SECOND AIR RETURN MEANS CONNECTING SAID FREEZER COMPARTMENT WITH THE LOWER PORTION OF SAID SECOND CHAMBER WHEREBY THE AIR STREAMS RETURNING FROM THE FREEZER AND FRESH FOOD COMPARTMENTS ARE KEPT SEPARATE UNTIL AFTER THE MOISTURE CONTENT OF THE AIR STREAM RETURNING FROM THE FRESH FOOD COMPARTMENT IS SUBSTANTIALLY LOWERED BY CONTACT WITH SAID FIRST EVAPORATOR SECTION.