EP0644385A1

EP0644385A1 - System for reducing frost in a refrigerator

Info

Publication number: EP0644385A1
Application number: EP94306536A
Authority: EP
Inventors: Jin Goo Park; Jun Chul Shin; Tae Su Kim
Original assignee: Daewoo Electronics Co Ltd
Current assignee: WiniaDaewoo Co Ltd
Priority date: 1993-09-04
Filing date: 1994-09-05
Publication date: 1995-03-22
Also published as: BR9403434A; CN1111343A; AU685140B2; AU7168494A

Abstract

A refrigerator has a freezing compartment (100), a cold storage compartment (110), and a refrigerating circuit (104, 112, 120) for refrigerating and circulating air to keep the two compartments at the required temperatures. The efficiency of the refrigerating circuit, which includes an evaporator (104) to refrigerate the air, is enhanced by reducing the moisture content of the circulated air before it is returned to the evaporator. In this respect, the air exiting both the freezing compartment (100) and the cold storage compartment (110) is directed to a return air duct (200) connected to deliver air to the evaporator (104). A partition (400) extends along the air duct such that air from the two compartments flows along opposite sides thereof in heat exchange relationship. To reduce the moisture content of the air, the partition (400) is made of material with a high thermal conductivity and/or incorporates a heater (403).

Description

Background of the Invention

1. Field of the Invention

The present invention relates to a system for reducing frost in a refrigerator, and more particularly to a system which can reduce moisture to be frosted on the outside of an evaporator in a refrigerator and thereby can improve the refrigeration efficiency or the coefficient of performance of the refrigerator.

2. Prior Arts

As is well known, a refrigerator is a household appliance for freezing or storing goods such as food at a cold temperature and/or in frozen by means of refrigerant circulating in a refrigeration cycle. That is, after compressed in a compressor, the refrigerant is condensed and liquified in a condenser, and evaporated in an evaporator, and expanded in an expander such as an expansion valve, and then flows to the compressor again.
In this process, the refrigerant absorbs heat from the surroundings in the course of evaporating in the evaporator so as to provide the refrigerator with a refrigerating force, and air circulates in a freezing room and/or a cold storage room after receiving the refrigerating force from the evaporator in the vicinity thereof, so that it freezes and/or cools the goods stored therein.
FIG. 1 is a schematic side sectional view of a conventional refrigerator 1 showing the flow of cold air, which deliver the refrigerating force into the freezing room and/or the cold storage room, in the refrigerator. As shown, refrigerator 1 has a freezing room 2, an evaporator 4 disposed at the rear of freezing room 2, and a return duct 5 disposed between freezing room 2 and cold storage room 3.
The air cooled in the course of passing through evaporator 4 is supplied into freezing and cold storage rooms 2 and 3, and then the air is returned to evaporator 4 after being warmed in the course of circulating in freezing and cold storage rooms 2 and 3.
In this case, the warmed air after circulating in freezing room 2 and cold storage room 3 contains much moisture, and this moisture is rapidly frozen and frosted on evaporator 4 in the course of passing through evaporator 4. When the evaporator is frosted, the thermal conductivity of the evaporator decreases and thereby the refrigeration efficiency or the coefficient of performance of the refrigerator is largely reduced. Therefore, in order to prevent this reduction of the coefficient of performance, a heater 6 is disposed in the vicinity of the evaporator, and the frost frozen on the exterior of the evaporator is removed by stopping refrigerator and at the same time operating heater 6.
However, in this method, because the operation of the refrigerator must be stopped during eliminating the frost so that it is difficult to maintain constant temperature in the freezing room or cold storage room, there is a possibility of deteriorating the food stored in frozen or in cold state in the refrigerator. Further, in case that heavy frost is frozen onto the evaporator, the duration and the times of stopping the refrigerator must be long and frequent so that the loss of heat increases heavily and the refrigeration efficiency is decreased.
A solution to eliminate the frost on the evaporator without using a heater so as to overcome the above disadvantage, is disclosed in USP No. 4,420,493 issued to Clawson. In Clawson's method and apparatus for refrigerator defrost, defrost is performed using the pressure difference between the condenser and the evaporator and the variation thereof in the process of refrigerating cycle. However, because the frost at the exterior of the evaporator is removed when the temperature of the evaporator is elevated in Clawson's method and apparatus also, an interruption in the intrinsic function of the evaporator, that is, the provision of refrigerating force is required for defrosting, which thereby can damage the refrigerating force and lower the coefficient of performance of the refrigerator.
Further, in USP No. 4,208,884 granted to Popham, there is disclosed a solution to eliminate the frost on the evaporator without interrupting the continuous provision of refrigerating force for the refrigerator by the evaporator.
Popham's air defrost housing includes a preformed unitary body section having opposite ends, a generally centrally located center chamber, a pair of generally cylindrically shaped valve chambers and associated dampers having conforming cylindrical wall sections generally located in the center of each end, and a pair of air passages extending at one end into each valve chamber and at the other end of the exterior. In the air defrost housing, ambient air is drawn into the housing from one end and discharged from the other end after flowing past the frosted coil by an energy saving air defrost system.
However, Popham's housing has a very complicated construction. Further, because defrost is accomplished by means of ambient air in Popham's housing, its defrosting ability is changed according to the temperature of ambient air, which can make the refrigeration efficiency of the refrigerator lowered largely.
It is an object of the present invention to provide a refrigerator having means to prevent formation of frost without adversely affecting the refrigeration cycle.
Accordingly to a first aspect of the present invention there is provided a refrigerator comprising a freezing compartment and a cold storage compartment, and a refrigerating circuit for refrigerating and circulating air to said compartments, said refrigerating circuit having an evaporator arranged to evaporate, and thereby refrigerate, the circulated air which is directed from the evaporator to said freezing compartment, characterised in that a return air duct is arranged to receive circulated air from each of said freezing and cold storage compartments and to direct the air back to said evaporator, in that a partition member extends within said return air duct such that the air received from said freezing and cold storage compartments generally flows along respective opposite surfaces of said partition member, and in that said partition member is arranged to reduce the moisture content of the air flowing therealong.
In an embodiment, to reduce the moisture content of the air flowing therealong said partition member is comprised of a material having a high thermal conductivity.
Additionally and/or alternatively, to reduce the moisture content of the air flowing therealong said partition member comprises heating means.
In a preferred embodiment, said partition member is mounted in said return air duct to be inclined downwardly with respect to the horizontal whereby moisture will drain therefrom, and wherein said refrigerating circuit further comprises a drain channel arranged to receive moisture draining from said base plate.
Said partition member preferably comprises a substantially planar base plate.
Alternatively, said partition member may comprise a base plate which has been corrugated to increase the surface area thereof.
In one embodiment, the corrugations of said base plate are substantially rectangular in cross-section.
In an alternative embodiment, the corrugations of said base plate are substantially arcuate in cross-section. In this case, adjacent arcuate cross-section corrugations may be alternatively convex or concave, or all of the corrugations may have the same curvature.
Preferably, said base plate is punctured to define a plurality of projections for guiding the flow of air along the base plate.
Alternatively, a plurality of pins are supported by said base plate and project relative the surfaces thereof.
The invention also extends to a system for reducing frost in a refrigerator, said system comprising:
a refrigerator housing including a freezing room and a cold storage room;
an evaporator operated as an element in a refrigeration cycle of the refrigerator to provide the freezing room and the cold storage room with a refrigerating force;
a first means for defining a multiduct enclosing the evaporator and interconnected to the freezing room and the cold storage room, to flow an air receiving the refrigerating force in the course of passing through the evaporator into the freezing room and the cold storage room;
a second means for defining a return duct interconnecting the multiduct and the freezing and cold storage rooms with each other in order for the air to return into the multiduct after having circulated in the freezing room and the cold storage room; and
a third means comprised of a material having a high thermal conductivity and dividing the return duct into a first duct and a second duct, the first duct interconnecting the freezing room and the multiduct with each other, and the second duct interconnecting the cold storage room and the mulitduct with each other.
Preferably, said third means is a frost-reducing partition member having a base plate, and two brackets disposed at the opposite sides of the base plate. The base plate may be a rectangular flat plate.
The third means may further comprise a heater disposed on the base plate.
The system may further comprise a fourth means for defining a drain channel interconnected to the return duct to drain water out from the return duct.
The present invention also extends to a system for reducing frost in a refrigerator, the system comprising:
a refrigerator housing including a freezing room and a cold storage room;
an evaporator operated as an element in a refrigeration cycle of the refrigerator to provide the freezing room and the cold storage room with refrigerating force;
a multiduct enclosing the evaporator and interconnected to the freezing room and the cold storage room in order for the air receiving the refrigerating force in the course of passing through the evaporator to flow into the freezing room and the cold storage room; and
a return duct interconnecting the multiduct and the freezing and cold storage rooms with each other in order for air to return into the multiduct after having circulated in the freezing room and the cold storage room; and
a frost-reducing partition member comprised of a material having a high thermal conductivity and having a base plate, and two brackets disposed at the opposite sides of the base plate, the frost-reducing partition member dividing the return duct into a first duct and a second duct, the first duct interconnecting the freezing room and the multiduct with each other, and the second duct interconnecting the cold storage room and the multiduct with each other.
According to one embodiment of the present invention, the system for reducing frost in a refrigerator may include a drain channel interconnected to the return duct to drain water out from the return duct, and the frost-reducing partition member may include a heater disposed on the base plate, and the base plate is a rectangular flat plate and is declined toward the drain channel.
According to another embodiment of the present invention, the base plate includes a plurality of upper and lower pins of high thermal conductivity respectively disposed at the upper and lower surfaces thereof, spaced out regular intervals apart. Each upper pin and each lower pin are incorporated with each other to extend through the base plate one pair by one pair, the diameter of each of the upper and lower pins is reducing toward the free end thereof.
According to another embodiment of the present invention, the base plate includes a plurality of rectangular upper sections, a plurality of rectangular lower sections, and a plurality of vertical sections each of which connects one of the upper sections and one of the lower sections with each other. A plurality of upper protrusions each of which extends toward the respective lower section corresponding thereto are formed at the inner upper surface of the return duct, and a plurality of lower protrusions each of which extends toward the respective upper section corresponding thereto and two support columns for preventing the sagging of the base plate are formed at the inner lower surface of the return duct.
According to another embodiment of the present invention, each of the upper and lower sections includes a plurality of pores, and a plurality of flaps each of which is disposed above the respective pore to guide air flowing therethrough.
According to another embodiment of the present invention, the base plate includes a plurality of longitudinally extending arcuate plates, the opposite sides of the respective arcuate plates are connected incorporated respectively with one side of the arcuate plate adjacent thereto, and concave portions of the arcuate plates facing toward the second duct in the return duct.
According to the system for reducing frost in a refrigerator of the present invention, the freezing of frost on the exterior of the evaporator is previously prevented or reduced without stopping the provision of refrigerating force for the freezing or cold storage rooms of the refrigerator by previously reducing moisture in the air passing through the evaporator.

Brief Description of the Drawings

The above objects and other advantages of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings in which:

FIG. 1 is a schematic side sectional view of a conventional refrigerator;
FIG. 2 is a schematic side sectional view of a refrigerator having a system for reducing frost therein according to one embodiment of the present invention;
FIG. 3 is an enlarged view of a return duct in which a frost-reducing partition member disposed in the refrigerator shown in FIG. 2 is disposed;
FIG. 4 is a perspective view of the frost-reducing partition member shown in FIG. 2;
FIG. 5 is a perspective view of a frost-reducing partition member according to another embodiment of the present invention;
FIG. 6 is a longitudinal sectional view of a return duct in which the frost-reducing partition plate shown in FIG. 5 is disposed;
FIG. 7 is a perspective view of a frost-reducing partition member according to another embodiment of the present invention;
FIG. 8 is a side sectional view of a return duct in which the frost-reducing partition plate shown in FIG. 7 is disposed;
FIG. 9 is a longitudinal sectional view of a return duct in which the frost-reducing partition plate shown in FIG. 7 is disposed;
FIGs. 10A to 10C are views for describing the process of the formation of frost on the frost-reducing partition member shown in FIGs. 5 to 7;
FIG. 11 is a perspective view of a frost-reducing partition member according to another embodiment of the present invention;
FIGs. 12A to 12C are views for describing the process of the formation of frost on the pins of the frost-reducing partition member shown in FIG. 11;
FIG. 13 is a schematic side elevation of a pin of another type disposed on the frost-reducing partition member shown in FIG. 11;
FIG. 14 is a perspective view of a frost-reducing partition member according to another embodiment of the present invention;
FIGs. 15A to 15C are views for describing process of the formation of frost on the frost-reducing partition member shown in FIG. 14; and
FIG. 16 is a side sectional view of a return duct in which the frost-reducing partition plate shown in FIG. 15 is disposed.

Description of the Preferred Embodiment

Hereinafter, the present invention will be described in detail referring to the accompanying drawings.

Embodiment 1

FIG. 1 is a schematic side sectional view of a refrigerator having a system for reducing frost therein according to a first embodiment of the present invention. The refrigerator includes a freezing room 100, a cold storage room 110, and a partition wall 102 disposed therebetween partitioning them. Return duct 200 is defined in partition wall 102, and a frost-reducing partition member 400 is disposed in return duct 200. An evaporator 104 is disposed in a multiduct 112 at the rear of freezing room 100.
FIG. 3 is an enlarged view of return duct 200 in which frost-reducing partition plate 400 is disposed. As shown, frost-reducing partition plate 400 divides return duct to a first duct 201 and a second duct 202. First duct 201 interconnects freezing room 100 and multiduct 112 with each other, and the second duct 202 interconnects cold storage room 110 and multiduct 112 with each other. A drain channel 120, which is interconnected to return duct 200 and multiduct 112, is defined under multiduct 112.
Frost-reducing partition plate 400 includes a base plate 401, and two brackets 402 disposed at the opposite sides of base plate 401, as shown in FIG. 4. A heater 403 is disposed on base plate 401. Base plate 401 is made of a material of a high thermal conductivity (a metal such as zinc or aluminum), and is declined toward drain channel 120.
Meanwhile, in the refrigerator provided with the system for reducing frost therein having the above construction according to the present embodiment, air having received refrigerating force from evaporator 104 in multiduct 112 in the course of passing therethrough flows into freezing room 100 and cold storage room 110 through multiduct 112. And then, the air returns into multiduct 112 through first duct 201 after circulating in freezing room 100 and through second duct 202 after circulating in cold storage room 110.
In this case, because the temperature of the air passing through first duct 201 is relatively lower than that of the air passing through second duct 202, heat-conduction is happened through base plate 401 of a high thermal conductivity. Accordingly, the air passing through second duct 202 from cold storage room 110 is cooled and thereby the relative humidity of the air is elevated, so that a large quantity of moisture included in the air is frosted or frozen on the lower surface of base plate 401.
Therefore, the total quantity of moisture in the air returning to multiduct 112 after passing through first and second ducts 201 and 202 is reduced, and thereby the quantity of frost on evaporator 104 is largely reduced.
In the meantime, the heat conductivity of base plate 401 gradually decreases according as the quantity of frost frozen on base plate 401 increases, and the passage of the air is closed when to much frost is frozen thereon.
Accordingly, to prevent this closure, heat 403 is operated to thaw frost frozen on base plate 401 when a predetermined quantity of frost is frozen thereon. This thawed water flows along the declined base plate 401 to be drained out through drain channel 120.

Embodiment 2

FIGs. 5 and 6 are sectional views of a frost-reducing partition member 500 and a return duct 540 enclosing frost-reducing partition member 500, according to the second embodiment of the present invention. Frost-reducing partition plate 500 includes a plurality of rectangular upper sections 510, a plurality of rectangular lower sections 520, and a plurality of vertical sections 530 respectively interconnecting respective upper sections and respective lower sections 520 with each other. Two brackets 502 are provided at the opposite sides of base plate 501. A linear heater 505 is disposed on respective lower sections 520. A plurality of upper protrusions 511 extending toward respective lower sections 520 corresponding thereto are formed at the upper inner surface of return duct 540, and a plurality of lower protrusions 512 extending toward respective upper sections 510 corresponding thereto and two support columns 543 for preventing sagging of base plate 501 are formed at the lower inner surface of return duct 540. The reference numerals 541, which are not described above, respectively designate a first duct and a second duct which are partitioned by base plate 501.
Frost-reducing partition member 500 according to the present embodiment is not flat but uneven, and thereby the total area, that is the heat-conduction area between the airs flowing through first and second ducts 541 and 542, is larger than that in the preceding embodiment. Therefore, the effect of reducing frost can be augmented compared with that in case of adopting the flat base plate.

Embodiment 3

FIG. 7 shows a frost-reducing partition member 600 according to a third embodiment of the present invention. Frost-reducing partition member 600 includes a construction similar to that of partition plate 500 shown in FIG. 5. That is, frost-reducing partition member 600 has a base plate 601. Base plate 601 includes a plurality of upper sections 610, a plurality of lower sections 620, and a plurality of vertical sections 630 respectively interconnecting respective upper sections 610 and respective lower sections 620 with each other. Two brackets 602 are disposed at the opposite sides of base plate 601. However, it is different from partition plate 500 shown in FIG. 5, in that a plurality of pores 608 are formed on respective upper sections 610 and lower sections 620, and a plurality of flaps 607 for guiding air flowing through pores 608 are respectively disposed above respective pores 608.
FIG. 8 is a side sectional view of return duct 640 in which frost-reducing partition member 600 is disposed, and FIG. 9 is a sectional view cut along the K-K line in FIG. 8. As shown, frost-reducing partition member 600 divides return duct 640 into a first duct 641 and a second duct 642. Further, a linear heater 605 is disposed at respective lower sections 620.
According to the present embodiment, because air can flow from second duct 642 to first duct 641 through pores 608 formed at respective upper and lower sections of frost-reducing partition member 600, frost can be frozen not only at the lower surface but also at the upper surface of base plate 601.
Therefore, the intervals between the times to thaw the frost frozen on the base plate can be elongated. Meanwhile, according to the second and third embodiments described above, there can be a difference between heat conducted through upper sections 510 and 610 and heat through lower sections 520 and 620 when the formation of frost on partition members 500 and 600 progresses, and thereby the formation frost can be concentrated on a specific region and can close the return duct in the event, as shown in FIGs. 10A to 10C.
The fourth and fifth embodiments has been made to overcome the above disadvantage.

Embodiment 4

FIGs. 11 to 13 show a base plate 701 of a frost-reducing partition member according to a fourth embodiment of the present invention. Base plate 701 is of a rectangular flat plate, and a plurality of upper pins 702 and lower pins 703 are provided respectively at the upper and lower surfaces of base plate 701. Upper and lower pins 702 and 703 are made of a metal of a high thermal conductivity such as zinc, aluminum, etc., as is base plate 701.
In the present embodiment, respective upper pins 701 and respective lower pins 703 are formed incorporated with each other one pair by one pair, and the respective resultant pins of incorporate bodies extend through base plate 701. Upper and lower pins 702 and 703 are spaced out regular intervals apart. Further, each of upper and lower pins 702 and 703 has decreasing diameter toward free end thereof. Each of pins 702 and 703 can have various shape, and particularly a conical shape as shown in FIG. 3.
According to the present embodiment, the heat conduction area is increased while the possibility of integration between the frosts adjacent to each other is very low, due to the construction of pins 702 and 703.
Especially, in case that each pin has a conical shape as shown in FIG. 13, the possibility of integration between the adjacent frosts is further lowered.
FIGs. 12A to 12C show process of forming frost on pins 702 and 703 of base plate 701.

Embodiment 5

FIGs. 14 and 15 show a base plate 801 of a frost-reducing partition member according to a fifth embodiment of the present invention. Base plate 801 has a plurality of longitudinally extending arcuate plate 802. The opposite sides 812 of respective arcuate plates 802 are connected incorporated with the adjacent side 812 of adjacent arcuate plate 802. Base plate 801 is disposed in return duct 840 in such a manner that concave portions of base plate 801 face toward second duct 842, as shown in FIG. 16. FIGs. 15A to 15C show the process of forming frost on base plate 801.
According to the present embodiment, there is almost no possibility of integration between the frosts adjacent to each other while the heat conduction area is increased, as is according to the fourth embodiment. It is because relatively large heat exchange or heat conduction is happened at the opposite sides 812 of each side 812 of arcuate plate 802 is very small compared with the interval between the sides 812.
By the system for reducing frost in a refrigerator according to the present invention as described above, by reducing the quantity of moisture passing through the evaporator, the freezing of frost on the exterior of the evaporator is previously prevented or reduced without stopping the provision of refrigerating force for the freezing room or the cold storage room of the refrigerator by the evaporator.
Accordingly, the formation of frost on the exterior of the evaporator is very small compared with that in a conventional refrigerator, and thereby the intervals between time to operate the heater to thaw frost frozen on the evaporator can be largely elongated.
Therefore, good and constant state of food stored in the freezing room and the cold storage room is guaranteed because the temperatures in the freezing and cold storage room is guaranteed because the temperatures in the freezing and cold storage rooms are maintained constant.
Furthermore, the construction of the system is simple, and thereby the manufacture thereof is easy and the manufacturing cost thereof is inexpensive.
It is understood by those skilled in the art that the foregoing description is a preferred embodiment of the disclosed system for reducing frost in a refrigerator and that various changes and modifications may be in the invention without departing from the spirit and scope thereof.

Claims

A refrigerator comprising a freezing compartment (100) and a cold storage compartment (110), and a refrigerating circuit (104, 112, 120) for refrigerating and circulating air to said compartments (100, 110), said refrigerating circuit having an evaporator (104) arranged to evaporate, and thereby refrigerate, the circulated air which is directed from the evaporator to said freezing compartment (100), characterised in that a return air duct (200, 540, 640, 840) is arranged to receive circulated air from each of said freezing and cold storage compartments (100, 110) and to direct the air back to said evaporator (104), in that a partition member (400, 500, 600, 701, 801) extends within said return air duct (200, 540, 640, 840) such that the air received from said freezing and cold storage compartments (100, 110) generally flows along respective opposite surfaces of said partition member, and in that said partition member (400, 500, 600, 701, 801) is arranged to reduce the moisture content of the air flowing therealong.
A refrigerator as claimed in Claim 1, wherein to reduce the moisture content of the air flowing therealong said partition member (400, 500, 600, 701, 801) is comprised of a material having a high thermal conductivity.
A refrigerator as claimed in Claim 1 or Claim 2, wherein to reduce the moisture content of the air flowing therealong said partition member (400, 500, 600, 701, 801) comprises heating means (403, 505).
A refrigerator as claimed in any preceding claim, wherein said partition member is mounted in said return air duct to be inclined downwardly with respect to the horizontal whereby moisture will drain therefrom, and wherein said refrigerating circuit further comprises a drain channel (120) arranged to receive moisture draining wherein said refrigerating circuit further comprises a drain channel (120) arranged to receive moisture draining from said plate.
A refrigerator as claimed in any preceding claim, wherein said partition member comprises a substantially planar base plate (401).
A refrigerator as claimed in any of Claims 1 to 4, wherein said partition member comprises a base plate (501, 601, 801) which has been corrugated to increase the surface area thereof.
A refrigerator as claimed in Claim 6, wherein the corrugations (510, 520; 610, 620) of said base plate (501, 601) are substantially rectangular in cross-section.
A refrigerator as claimed in Claim 6, wherein the corrugations (802) of said base plate (801) are substantially arcuate in cross-section.
A refrigerator as claimed in any of Claims 5 to 8, wherein said base plate (401, 501, 601) is punctured to define a plurality of projections (607) for guiding the flow of air along the base plate.
A refrigerator as claimed in any of Claims 5 to 8, wherein a plurality of pins (702,703) are supported by said base plate (701) and project relative the surfaces thereof.