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(11) | EP 0 974 794 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Refrigerator with evaporator positioned within the preservation compartment roof Kühlschrank mit in der Decke des Bewahrungsfaches angeordenetem Verdampfer Réfrigérateur avec un évaporateur situé dans le plafond du compartiment de conservation |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] This invention relates generally to a domestic refrigerator comprising at least one preservation compartment cooled by evaporator means. More particularly, the invention relates to a domestic refrigerator with automatic defrosting.
[0002] Refrigerators are known in the most varied constructions, all tending to improve their power consumption and hence their efficiency, and to reduce the thermal load of the evaporator.
However a margin always exists for possible improvements to known constructions aimed at achieving further benefits.
[0003] US-A-2589550 discloses a refrigerator with a preservation compartment surrounded by a tank filled with an eutectic brine. JP 02017374, on which the preamble of the attached claim 1 is drafted, discloses a cold storage chamber having plate type heat ccumulating members into contact with the outer wall surfaces of an inner casing of the storage chamber.
GB-A-1216414 discloses a freezer compartment with a cold storer, which consists of a collapsible envelope and contains a fluid having great heat capacity.
[0004] An object of the invention is to improve refrigerators of the indicated type such as to appreciably lower their power consumption.
[0005] This and further objects which will be apparent from the ensuing detailed description are attained by a refrigerator of the indicated type, the inventive aspects of which are defined in the accompanying claims.
[0006] The invention will be more apparent from the detailed description of preferred embodiments thereof given hereinafter by way of non-limiting example and illustrated on the accompanying drawings, on which:
Figure 1 is a schematic vertical section through a refrigerator according to the invention;
Figure 2 is a schematic section through the roof of the refrigerator of Figure 1;
Figure 3 is a schematic perspective view of that shown in Figure 2.
[0007] In the figures, the reference numeral 1 indicates overall a refrigerator shown without its door and other members such as the compressor and condenser as these are conventional and do not concern the invention.
[0008] A conventional evaporator 4 extends in contact with the vertical rear wall 2 and possibly with the side walls which bound the preservation compartment 3 of the refrigerator.
[0009] According to the invention a further evaporator 5 is provided in correspondence with the roof 6 which upperly bounds the preservation compartment. This further evaporator can be a section of the other evaporator or be an evaporator connected to the preceding by a trottling means such as a conventional capillary 7.
[0010] The evaporator 5, whether forming a part or section of the evaporator 4 or whether connected to it via the capillary 7, is positioned upstream of the evaporator 4 with reference to the direction of flow of the refrigerant fluid through the evaporators.
[0011] According to the invention, the evaporator 5 is not in direct contact with the roof of the preservation compartment 3, but is spaced from it in that it rests either directly, or indirectly via a sheet for example of polyethylene or another similar plastic material, on a panel or cushion 9. This latter is preferably divided into communicating or non-communicating compartments and comprises a flexible or substantially rigid eutectic-containing enclosure of plastic material such as polyethylene, or metal such as aluminium, or aluminized plastic, or plastic filled with a heat conducting material.
[0012] In the case of a substantially rigid enclosure, it can be of a shape such as to compensate any deformation due to the changes of state of the eutectic so as not to deform the roof 6, in addition to the provision of expansion volumes for the eutectic within the enclosure.
[0013] The eutectic is chosen such as to change its state at a temperature of not less than -10°C, preferably 0°C, the layer formed by the eutectic (minus the thickness of the enclosure), ie the quantity of eutectic contained, and the type of eutectic being such that under the refrigerator operating conditions the roof temperature never falls below a value such as to result in formation of condensate or frost on the underside of the roof. A possible electrical resistance element of suitable power, for example positioned on that surface of the eutectic facing the compartment 3, can prevent condensate or frost appearing on said surface. Alternatively the resistance element can be advantageously replaced by a part of the usual capillary tube connecting the usual condenser (not shown) of the refrigeration circuit to said evaporator, and positioned in correspondence with said surfaces of the eutectic. This has the advantage of recovering the energy dispensed by the eutectic in addition to preventing the formation of the condensate or frost. Examples of such eutectics are KNO3/H2O and KCl/H2O, or simply H2O.
[0014] The evaporator 5 upstream of the evaporator 4 can also be bonded to the eutectic cushion 9 by adhesives instead of resting thereon directly or indirectly.
[0015] In the refrigerator example shown on the drawings, the evaporators and the eutectic cushion are conventionally embedded in a mass of expanded polyurethane material 10. Arrangements are however possible, all falling within the scope of the invention, in which the evaporator 4 (ie that on the rear) and any evaporators or sections present on the side walls of the compartment are visible, ie not embedded and hence actually lying within the preservation compartment 3. The roof evaporator 5 can also be provided in an exposed position, but in this case it will be substantially clad by the eutectic cushion.
[0016] The concept on which the invention is based consists of appreciably reducing (as much as by 20-30%) the refrigerator power consumption by virtue of the increase in the evaporating surface, the greater efficiency of the refrigeration cycle in that evaporation can take place at a higher temperature because of the greater evaporating surface, and a lower thermal load on the evaporator.
1. A refrigerator with at least one preservation compartment (3) cooled by evaporator
means (4, 5), the evaporator means (4, 5) comprising a part (4) involving at least
one of the vertical walls of the preservation compartment (3) and a part (5) positioned
in correspondence with the roof (6) of the preservation compartment (3), characterised in that only the evaporator part (5) in correspondence with the roof (6) transmits its cold
to the compartment (3) via an eutectic layer (9), and the evaporator part (4) involving
the vertical wall or walls being positioned downstream of the other part in the direction
of flow of the refrigerant fluid.
2. A refrigerator as claimed in claim 1, wherein the eutectic is chosen such as to have
a solidification temperature of not less than -10°C, preferably 0°C, so that under
operating conditions the roof temperature does not fall below a value such as to cause
condensate or frost to form on the underside of the roof (6) of the preservation compartment
(3).
3. A refrigerator as claimed in the preceding claims, wherein the eutectic layer (9)
is enclosed in an enclosure defining a cushion on which that part (5) of the evaporator
means relative to the roof (6) lies either directly or indirectly.
4. A refrigerator as claimed in claim 3, characterised in that the enclosure is flexible.
5. A refrigerator as claimed in claim 3, characterised in that the enclosure is rigid.
6. A refrigerator as claimed in claim 1, wherein the evaporator parts (4, 5) are connected
together via a capillary (7).
1. Kühlschrank mit zumindest einem Aufbewahrungs-Kompartiment (3), das durch Verdampfer-Elemente
(4, 5) abgekühlt wird, wobei die Verdampfer-Elemente (4, 5) einen Teil (4) umfassen,
der zumindest eine der vertikalen Wände des Aufbewahrungs-Kompartiments (3) einbezieht,
sowie einen Teil (5), der in Übereinstimmung mit der Decke (6) des Aufbewahrungs-Kompartiments
(3) positioniert ist, dadurch gekennzeichnet, dass nur der Verdampfer-Teil (5) in Übereinstimmung mit dem Deckel (6), der Kälte auf
das Kompartiment (3) über eine eutektische Schicht (9) übermittelt, und der Verdampfer-Teil
(4), der die vertikale Wand oder Wände einbezieht, stromabwärts des anderen Teils
in der Richtung des Stroms der Kühlflüssigkeit positioniert ist.
2. Kühlschrank wie in Anspruch 1 bezeichnet, wobei das Eutektikum so ausgewählt ist,
dass es eine Verfestigungstemperatur von nicht weniger als -10°C, vorzugsweise 0°C
aufweist, so dass unter Betriebsbedingungen die Deckeltemperatur nicht unterhalb einen
Wert abfällt, um eine Kondensierung oder ein Anfrieren an der Unterseite des Deckels
(6) des Aufbewahrungs-Kompartiments (3) zu bewirken.
3. Kühlschrank wie in einem der voranstehenden Ansprüche bezeichnet, wobei die eutektische
Schicht (9) in einer Einhausung eingeschlossen ist, die ein Kissen definiert, an dem
der Teil (5) des Verdampfer-Elements in Bezug auf den Deckel (6) entweder direkt oder
indirekt anliegt.
4. Kühlschrank wie in Anspruch 3 bezeichnet, dadurch gekennzeichnet, dass die Einhausung flexibel ist.
5. Kühlschrank wie in Anspruch 3 bezeichnet, dadurch gekennzeichnet, dass die Einhausung starr ist.
6. Kühlschrank wie in Anspruch 1 bezeichnet, wobei die Verdampfer-Teile (4, 5) miteinander
über eine Kapillare (7) verbunden sind.
1. Réfrigérateur avec au moins un compartiment de conservation (3) refroidi par des moyens
d'évaporateur (4, 5), les moyens d'évaporateur (4, 5) comportant une partie (4) impliquant
au moins une des parois verticales du compartiment de conservation (3) et une partie
(5) positionnée en correspondance avec le toit (6) du compartiment de conservation
(3), caractérisé en ce que seule la partie d'évaporateur (5) en correspondance avec le toit (6) transmet son
froid au compartiment (3) par l'intermédiaire d'une couche d'eutectique (9), et la
partie d'évaporateur (4) impliquant la paroi ou les parois verticales étant positionnée
en aval de l'autre partie dans la direction d'écoulement du fluide réfrigérant.
2. Réfrigérateur selon la revendication 1, dans lequel l'eutectique est choisi de façon
à avoir une température de solidification qui n'est pas inférieure à - 10°C, de préférence
0°C, de telle sorte que, dans des conditions de fonctionnement, la température de
toit ne tombe pas en dessous d'une valeur telle que cela amène une condensation ou
du givre à se former sur le côté inférieur du toit (6) du compartiment de conservation
(3).
3. Réfrigérateur selon les revendications précédentes, dans lequel la couche d'eutectique
(9) est enfermée dans une enceinte définissant un lit sur lequel la partie (5) des
moyens d'évaporateur par rapport au toit (6) repose directement ou indirectement.
4. Réfrigérateur selon la revendication 3, caractérisé en ce que l'enceinte est flexible.
5. Réfrigérateur selon la revendication 3, caractérisé en ce que l'enceinte est rigide.
6. Réfrigérateur selon la revendication 1, dans lequel les parties d'évaporateur (4,
5) sont reliés par l'intermédiaire d'un capillaire (7).