EP0298347A2

EP0298347A2 - Refrigerator with rapid-cooling feature

Info

Publication number: EP0298347A2
Application number: EP88110315A
Authority: EP
Inventors: Paolo Marega; Luciano Pesavento
Original assignee: Industrie Zanussi SpA
Current assignee: Industrie Zanussi SpA
Priority date: 1987-07-09
Filing date: 1988-06-28
Publication date: 1989-01-11
Also published as: EP0298347A3; IT8745733A0; IT1220061B

Abstract

A refrigerator comprises an enclosed compartment (5) normally kept at a food storage temperature. Means (16) for creating a forced air circulation within the compartment are normally inoperative and adapted to be selectively activated by manually operable control means (17) for the performance of temporary rapid-cooling phases.

Description

The present invention relates to an automatic refrigerator, particularly of the domestic type, comprising an enclosed compartment for the storage of foods at a nominal temperature of between about 0 and 10 °C.
In refrigerators of this type, the cooling of foods placed into the compartment at ambient temperature takes an undesirably long time of several hours. When rapid cooling of such foods is required, it is therefore common practice to temporarily place these foods in a freezer compartment which may be provided in the refrigerator itself or in a separate appliance. The awkwardness of this procedure is well known; in addition, the user might easily forget the foods in the freezer compartment, so that they can no longer be used (as for instance bottled beverages).
It is therefore an object of the invention to provide a refrigerator of simple construction in which the foods can be rapidly cooled if so desired without their having to be temporarily placed in a freezer compartment.
According to the invention, this object is attained in a refrigerator with rapid-cooling feature, comprising an automatically operating refrigerant circuit for maintaining at least one enclosed compartment at a suitable temperature for the storage of foods. A refrigerator of this type is characterized by comprising forced air circulation means disposed in said compartment, said forced air circulation means being normally substantially inoperative and adapted to be selectively activated by the use of associated control means.
The characteristics and advantages of the invention will become more clearly evident from the following description, given by way of example with reference to the accompanying drawings, wherein:

fig. 1 shows a diagrammatic illustration of the operating principle of a preferred embodiment of the invention, and
figs. 2 to 4 show different embodiments of electric circuits for controlling the operation of the refrigerator of fig. 1.

With reference to fig. 1, the refrigerator 7 according to the invention comprises an enclosed compartment 5 which is accessible through a door 6. Compartment 5 is refrigerated by an evaporator 8 belonging to a conventional refrigerant circuit otherwise including a compressor 9, a condenser 10, a dehydrating filter 11 and a lamination element 12. In a per se known manner, a thermostat device 13 for controlling the compartment temperature is itself controlled by a sensor 14 adapted to sense the temperature of evaporator 8 for determining the initiation and duration of the periodic operating cycles of compressor 9. Thermostat device 13 may of course also be controlled by a sensor (not shown) adapted to sense the temperature within the volume of compartment 5. In each case the refrigerant circuit is operated to maintain the interior of compartment 5 at a suitable temperature for the storage of foods 15, comprised between about 0 and 10 °C.
Housed in compartment 5 is at least one motor-driven fan 16 which is normally inoperative (or operating at a low speed) and adapted to be selectively activated by the user by means of manually operated control means comprising for instance a switch 17 disposed on an outer control panel of the appliance. As specifically shown in fig. 2, switch 17 is normally open and connected in series with the electric motor 18 of fan 16 between two electric power supply phases 19, 20. Preferably connected parallel to motor 18 in a manner to be activated simultaneously with fan 16 is an indicator device such as a warning lamp 21 or the like disposed on the control panel of the appliance.
When it is desired to rapidly cool foods placed into compartment 5 at for instance ambient temperature, it suffices to close switch 17 for activating fan 16 and warning lamp 21. Fan 16, the rotational speed of which may optionally be variable by means of a variable resistor or the like (not shown), creates within compartment 5 a closed-circuit forced air circulation (represented by arrows in fig. 1) enveloping foods 15. Independent of the actual temperature values, this air flow substantially accelerates the thermal exchange between the air volume within compartment 5 and foods 15, so that the latter are rapidly cooled in conformity with the object of the invention.
In practical experiments it has been found for instance that a body 15 having a temperature of 32 °C and placed into compartment 5 having a temperature of 5 °C takes about 12 hours to cool down to a temperature of 10 °C when fan 16 is inoperative but only about 3 hours when fan 16 is in operation.
Warning lamp 21 is of course provided for indicating to the user the operating state of fan 16 to thereby avoid operating phases of excessive duration.
This problem may be solved in an automatic manner by the modified embodiment shown in fig. 3, in which a thermostatic safety switch 22 is connected in series with switch 17 and motor 18 between phases 19 and 20. As shown in phantom lines in fig. 1, thermostatic safety switch 22 is preferably located in the lowermost (and thus coolest) part of compartment 5. It is normally closed and adapted to open when the temperatrue within compartment 5 drops below a predetermined minimum value of for example -1 °C.
In this embodiment the operation of the refrigerator is substantially the same as described above, with the only difference that safety switch 22 automatically deactivates fan 16, even with switch 17 closed, when the user has forgotten to switch back to normal operation of the refrigerator. In this embodiment indicator device 21 may also be omitted, although it is preferably retained an connected parallel to motor 18 and safety switch 22 so as to indicate the closed condition of switch 17 in any case.
Another modified embodiment rendering the provision of indicator device 21 superfluous is shown in fig. 4, in which manually operable switch 17 cooperates with a timer 23, for instance of the mechanical type, operable to determine the duration of the closed state of switch 17 and preferably adjustable in a known manner.
The above description clearly shows the structural and functional simplicity of the refrigerator according to the invention and the possibility of rapidly cooling foods without the necessity of expensive auxiliary equipment, in particular as regards the refrigerant circuit. It is also to be noted that also during the periods of forced air circulation the humidity within the enclosed volume of compartment 5 remains substantially unchanged, as also established by experimentation.
It has even be found that the operation of fan 16 results in a more uniform distribution of the humidity within compartment 5. As generally known, this results in optimum storage conditions for the foods stored in the compartment, the volume of which may therefore be utilized in a more rational manner.
It is to be understood that the described refrigerator may undergo various modifications within the scope of the invention. The described solutions may thus be combined in any suitable manner, and the means for creating the forced air circulation may be of any suitable construction. Furthermore manually operable switch 17 may be replaced by an automatic switch, for instance a thermostat-controlled switch responsive to the temperatore of at least some of the stored foods. A switch of this type may for instance be provided with a per se known thermosensor adapted to be placed in contact with the foods and preferably adjustable for selecting a suitable cooling temperature.

Claims

1. A refrigerator with rapid-cooling feature, comprising an automatically operating refrigerant circuit for normally maintaining at least one enclosed compartment at a temperature for the storage of foods, characterized by additionally comprising means (16) for creating a forced air circulation within said compartment (5), said means being normally substantially inoperative and adapted to be selectively activated by the use of control means (17).

2. A refrigerator with rapid-cooling feature according to claim 1, characterized by comprising indicator means (21) adapted to be activated by the use of said control means (17) simultaneously with said forced air circulation means (16).

3. A refrigerator with rapid-cooling feature according to claim 1, wherein said forced air circulation means comprise an electric motor driving a fan, and said control means comprise an electric switch, characterized in that said electric switch (17) is operable to energize said electric motor (18) through a normally closed thermostatic switch (22) adapted to open when the temperature within said compartment (5) drops below a predetermined minimum value.

4. A refrigerator with rapid-cooling feature according to claim 1, characterized in that said control means (17) is associated to timer means (23) operable to determine the operating time of said forced air circulation means (16).

5. A refrigerator with rapid-cooling feature according to claim 1, characterized in that said control means (17) comprise a thermostat-controlled switch responsive to the temperature of the foods (15).