EP2146164A2

EP2146164A2 - Household refrigeration appliance, in particular of the no-frost type

Info

Publication number: EP2146164A2
Application number: EP09165314A
Authority: EP
Inventors: Giorgio Sabatini
Original assignee: Indesit Co SpA
Current assignee: Whirlpool EMEA SpA
Priority date: 2008-07-15
Filing date: 2009-07-13
Publication date: 2010-01-20
Also published as: EP2146164A3; ITTO20080541A1; RU2009127172A; RU2498168C2; IT1391479B1

Abstract

The present invention relates to a household refrigeration appliance (1), in particular of the no-frost type, fitted with at least one inner compartment (10, 20) for preserving foodstuffs and with a refrigerating chamber (30) comprising:
- an evaporator (31) adapted to cool the air;
- a fan (32), associated with a motor (33), for circulating the air inside said at least one inner compartment (10, 20).

The invention is characterized in that said evaporator (31) comprises a conveying septum (35) adapted to subdivide said refrigerating chamber (30) into a first compartment (30a) and a second compartment (30b), and to convey the air flow into said first (30a) and second (30b) compartment.

Description

The present invention relates to a household refrigeration appliance, in particular of the no-frost type, according to the preamble of claim 1.
In no-frost refrigeration appliances, heat is removed from foodstuffs by forced convection, thus generating a circulation of cold air inside the appliance; this feature distinguishes no-frost refrigeration appliances from static ones, i.e. without forced convection.
Another essential difference between no-frost and static refrigeration appliances is the different mode of defrosting, which is controlled electronically in no-frost refrigeration appliances (hence the designation "no-frost"), whereas it is carried out manually in static refrigeration appliances.
Known no-frost refrigeration appliances have at least one inner compartment for preserving foodstuffs. They typically comprise two inner compartments kept at different temperatures, thus providing at least two different foodstuffs preservation states, in particular a refrigerator compartment suitable for preserving fresh food at a temperature between 0°C and 10°C and a freezer compartment suitable for preserving frozen food; such refrigeration appliances are commonly referred to by those skilled in the art of household refrigeration as "double-door" or "combined" refrigerators, depending on the relative position of the two compartments. Furthermore, no-frost refrigeration appliances are equipped with a refrigerating chamber comprising:

an evaporator adapted to cool the air;
a fan for circulating the air inside the refrigeration appliance.

An example of a no-frost refrigeration appliance is described in European patent application No. EP1918664 in the name of the present Applicant.
It has been observed that known no-frost refrigeration appliances suffer from some drawbacks which are essentially due to the particular shape of the evaporator.
In particular, known evaporators comprise a coil-like tubular element having a plurality of fins adapted to increase the area of thermal exchange between the evaporator and the air to be cooled.
For the purpose of keeping the internal temperature of the refrigeration appliance constant over time at a desired value, said refrigeration appliance must be able to eliminate the heat entering the refrigerated environment, e.g. heat entering through the walls of the appliance, when a door is opened and when foodstuffs are placed into the refrigerator for being cooled and preserved. Additional heat is then due to endogenous causes, i.e. generated by heat sources arranged inside the refrigeration appliance itself, such as fan motors, lighting devices, etc.
When the refrigeration appliance is operating, a lot of moisture is generated inside of it. This is due to air entering from the outside (especially in the summer season, when absolute humidity is usually very high) as well as to the possible "breathing" process of the preserved products. This increased humidity is the main cause for the formation of frost on the evaporator fins.
It is also known that during the operation of the refrigeration appliance frost turns into compact ice, which may obstruct the air flow between the evaporator fins, resulting in a smaller flow section and a changed thermal exchange coefficient; as a consequence, the ice forming on the evaporator fins is detrimental for thermal exchange and causes inefficient fluid dynamics, because the air must necessarily flow through the meatuses around the evaporator. When the air to be cooled flows in peripheral regions of the evaporator, this inevitably leads to less effective cooling of the air flow and consequently to a lower efficiency of the refrigeration appliance.
It is also known that evaporator fins are connected to the coil-like tube by means of suitable joints; it follows that, due to the construction tolerances of these elements, it often happens that the contact between the outer tube walls and the fin ends is not optimal. Since the difference in temperature between the outer tube wall and the fin ends is great (up to about 15 degrees), a missing contact between said elements will determine a considerable reduction in the thermal exchange between the tube and the fins; consequently, the efficiency of the refrigeration appliance will be reduced even further. In this frame, it is the main object of the present invention to provide a household refrigeration appliance, in particular of the no-frost type, adapted to overcome the above-described drawbacks and to prove especially efficient and economical.
It is a further object of the present invention to provide a household refrigeration appliance, in particular of the no-frost type, so conceived as to ensure adequate cooling of the air flow used for food preservation.
These objects are achieved through a household refrigeration appliance, in particular of the no-frost type, incorporating the features set out in the appended claims, which are intended as an integral part of the present description.
Further objects, features and advantages of the present invention will become apparent from the following detailed description and from the annexed drawings, which are supplied by way of non-limiting example, wherein:

Fig. 1 is a sectional side view of a refrigeration appliance according to the present invention;
Fig. 2a is a sectional side view of a first embodiment of a detail of the refrigeration appliance according to the present invention;
Fig. 2b is a sectional side view of a second embodiment of a detail of the refrigeration appliance according to the present invention.

Referring now to Fig. 1, reference numeral 1 designates a household refrigeration appliance according to the present invention.
Refrigeration appliance 1 is a no-frost unit, i.e. of the type in which heat is removed by forced convection by means of cold air circulating inside of it.
Said refrigeration appliance 1 comprises at least one inner compartment 10, 20 for preserving foodstuffs.
In particular, refrigeration appliance 1 comprises a refrigerator compartment 10 adapted to preserve fresh food (typically at a temperature between 0°C and 10°C), and a freezer compartment 20 adapted to preserve frozen food.
In the drawing of Fig. 1, freezer compartment 20 is arranged on top of refrigerator compartment 10; it is however clear that the arrangement of compartments 10, 20 may also be different, i.e. freezer compartment 20 may alternatively be located under refrigerator compartment 10. Compartments 10 and 20 are closed by respective doors 11, 21; in particular, a first door 11 is used for closing refrigerator compartment 10, and a second door 21 is used for closing freezer compartment 20.
The representation of refrigeration appliance 1 provided in Fig. 1 only shows some of the elements commonly arranged inside a refrigeration appliance 1, such as a plurality of shelves 12 arranged at different heights; for simplicity, some other common components of a refrigeration appliance 1 are not shown in Fig. 1.
Refrigeration appliance 1 is provided with a refrigerating chamber 30 comprising:

an evaporator 31 adapted to cool the air;
a fan 32 associated with a motor 33 for circulating the cooling air inside refrigeration appliance 1.

The refrigerating power is generated by a compressor 40 belonging to a refrigerating circuit which also includes evaporator 31. Fig. 1 does not show the other components of the refrigerating circuit, in that such components are well known to those skilled in the art of household refrigeration; also, the drawing does not show a defrosting device which may be associated with evaporator 31.
The air cooled by evaporator 31 is circulated by fan 32 when the latter is operated by motor 33, and is then released inside refrigeration appliance 1, partly in freezer compartment 20 and partly in refrigerator compartment 10.
As regards refrigerator compartment 10, in particular, the air is conveyed through suitable distribution means, which preferably comprise:

a supply duct 13, preferably obtained within a dividing wall 14 between refrigerator compartment 10 and freezer compartment 20, said supply duct 13 being connected to a distribution duct 15 having a plurality of apertures 16 located at different levels of refrigerator compartment 10;
a gate valve 17, in particular arranged between supply duct 13 and distribution duct 15. Said gate valve 17, which is traditionally present in double-door or combined refrigeration appliances and is known in the art of household refrigeration as "damper", adjusts the flow rate of the cold air supplied to refrigerator compartment 10 according to the temperature sensed therein.

After having subtracted heat by forced convection from the foodstuffs contained in refrigerator compartment 10 and freezer compartment 20, and having thus warmed up, the cold air then returns to refrigerating chamber 30 and to evaporator 31.
In particular, refrigeration appliance 1 according to the present invention comprises:

a first intake duct 18 allowing the air to return to refrigerating chamber 30 from refrigerator compartment 10;
a second intake duct 34 allowing the air to return to refrigerating chamber 30 from freezer compartment 20.

Preferably, said first intake duct 18 is obtained within said dividing wall 14 arranged between refrigerator compartment 10 and freezer compartment 20.
Figs. 2a and 2b are sectional side views of a first and a second embodiment, respectively, of evaporator 31.
As can be seen in said Figs. 2a and 2b, according to the present invention evaporator 31 comprises a conveying septum 35 adapted to subdivide said refrigerating chamber 30 into a first compartment 30a and a second compartment 30b, and to convey the air flow into said first 30a and second 30b compartment.
Said conveying septum 35 extends in a substantially vertical direction inside said refrigerating chamber 30, thus optimizing air flow channeling within said refrigerating chamber 30.
In particular, in a first embodiment shown in Fig. 2a evaporator 31 comprises a staggered coil tube 36, i.e. a coil tube having a zig-zag cross-section, which allows to obtain a winding path for the air flow inside said first 30a and second 30b compartment, thus improving the convective thermal exchange between the air flow and evaporator 31. The path followed by the air flow is indicated in Fig. 2a by means of dashed arrows designated P1
In another possible embodiment, said coil tube 36 may have an elliptic cross-section, in particular for the purpose of directing the air flow in the most appropriate manner into said first 30a and second 30b compartment while providing a larger thermal exchange area in contact with the air flow.
Consequently, the special design of evaporator 31 according to the present invention ensures an adequate thermal exchange between coil tube 36 and the air even without using the fins commonly fitted to known evaporators.
Moreover, said evaporator 31 may be so designed as to comprise a coil tube 36 substantially wound around said conveying septum 35.
Referring now to the second embodiment shown in Fig. 2b, evaporator 31 comprises at least a first 37a and a second 37b refrigerating panel, in particular of the roll-bond type.
As known, the roll-bond production process is a technique for manufacturing diversly channelled panels by bonding a "sandwich" formed by two aluminium sheets through a rolling process.
The paths and dimensions of the channels obtained in panels thus manufactured are usually determined by a printing (silk screen) process carried out on one of the inner surfaces of the aluminium sandwich. The junction between the two inner surfaces of the sandwich is actually a welding obtained by combining temperature (sandwich pre-heating) and pressure (hot rolling). The surfaces do not weld together where a special ink is applied during the silk screen process, thus generating paths consisting of unwelded portions within the sandwich. Said unwelded portions can be raised by applying appropriate air pressure (inflating), thus transforming the unwelded paths into channelled paths.
As can be seen in Fig. 2b, said first 37a and second 37b refrigerating panel are located within said refrigerating chamber 30 on opposite sides with respect to conveying septum 35, so that said first 30a and second 30b compartment are subdivided into a plurality of regions, in particular a first region 38a, a second region 38b, a third region 38c and a fourth region 38d. Moreover, said first 37a and second 37b refrigerating panels comprise a channel 39 having an elongated cross-section, in particular hexagonal, for circulating a refrigerating fluid.
In Fig. 2b the paths of the air flows are designated by reference P2 and dashed arrows; it can be seen in this drawing that the air flows can lap both sides of said first 37a and second 37b refrigerating panel. It is therefore apparent that the provision of said first 37a and second 37b refrigerating panel in refrigerating chamber 30 allows to attain an optimal convective thermal exchange between the air flows and evaporator 31.
In addition, said convective thermal exchange is further improved by the special shape of channel 39, which ensures a more effective thermal exchange between evaporator 31 and the air.
The advantages of a household refrigeration appliance, in particular of the no-frost type, according to the present invention are apparent from the above description.
In particular, said advantages are due to the fact that the refrigeration appliance according to the present invention is so designed as to overcome the previously described drawbacks of prior-art refrigeration appliances and to be particularly effective and economical.
Another advantage offered by the refrigeration appliance according to the present invention is that it has been conceived in a manner such as to ensure adequate cooling of the air flow used for food preservation.
A further advantage of the refrigeration appliance according to the present invention is that it comprises an evaporator so designed as to ensure an optimal convective thermal exchange with the air flows getting in contact therewith.
Another advantage of the particular design of evaporator 31 according to the present invention is that it ensures an adequate thermal exchange between coil tube 36 and the air even without using fins as commonly fitted to known evaporators.
The refrigeration appliance described herein by way of example may be subject to many possible variations without departing from the novelty spirit of the inventive idea; it is also clear that in the practical implementation of the invention the illustrated details may have different shapes or be replaced with other technically equivalent elements.
Among the many possible variants, it is worth mentioning that evaporator 31 may comprise a plurality of refrigerating panels 37a, 37b, so as to further subdivide said first 30a and second 30b compartment and further enhance the convective thermal exchange between the air flows and evaporator 31.
According to another variant, said first refrigerating panel 37a and/or said second refrigerating panel 37b may be arranged in refrigerating chamber 30 in a manner such as to be substantially in contact with a first wall 22 and/or a second wall 23. In this variant, the simplicity of the arrangement of said first 37a and second 37b refrigerating panel allows refrigerating chamber 30 to be manufactured in a particularly economical manner. It is also apparent that in this variant said first 30a and second 30b compartment only comprise said second region 38b and a third region 38c.
Another variant is characterized by a special design of said first refrigerating panel 37a and/or said second refrigerating panel 37b, which are folded on itself in particular into a "G" or spiral-like shape so as to subdivide said first 30a and/or second 30b compartment into a greater number of regions 38a, 38b, 38c, 38d, thus further increasing the area of thermal exchange between evaporator 31 and the air.
It can therefore be easily understood that the present invention is not limited to the above-described refrigeration appliance, but may be subject to many modifications, improvements or replacements of equivalent parts and elements without departing from the inventive idea, as clearly specified in the following claims.

Claims

Household refrigeration appliance (1), in particular of the no-frost type, fitted with at least one inner compartment (10, 20) for preserving foodstuffs and with a refrigerating chamber (30) comprising:
- an evaporator (31) adapted to cool the air;

- a fan (32), associated with a motor (33), for circulating the air inside said at least one inner compartment (10, 20),

characterized in that

said evaporator (31) comprises a conveying septum (35) adapted to subdivide said refrigerating chamber (30) into a first compartment (30a) and a second compartment (30b), and to convey an air flow into said first (30a) and second (30b) compartments.
Refrigeration appliance (1) according to claim 1, characterized in that said conveying septum (35) extends in a substantially vertical direction inside said refrigerating chamber (30), thus optimizing air flow channelling within said refrigerating chamber (30).
Refrigeration appliance (1) according to claim 1, characterized in that said evaporator (31) comprises a staggered coil tube (36), i.e. a coil tube having a zigzag cross-section, which allows to obtain a winding path for the air flow inside said first (30a) and second (30b) compartment, thus improving the convective thermal exchange between the air flow and the evaporator (31).
Refrigeration appliance (1) according to claim 3, characterized in that said coil tube (36) has an elliptic cross-section for the purpose of directing the air flow in the most appropriate manner into said first (30a) and second (30b) compartment and of providing a larger surface in contact with the air flow.
Refrigeration appliance (1) according to claim 3, characterized in that said coil tube (36) is substantially wound around said conveying septum (35).
Refrigeration appliance (1) according to claim 1, characterized in that said evaporator (31) comprises at least a first (37a) and a second (37b) refrigerating panel, in particular of the roll-bond type.
Refrigeration appliance (1) according to claim 6, characterized in that said first (37a) and second (37b) refrigerating panel are located within said refrigerating chamber (30) on opposite sides with respect to the conveying septum (35), so that said first (30a) and second (30b) compartment are subdivided into a plurality of regions, in particular a first region (38a), a second region (38b), a third region (38c) and a fourth region (38d).
Refrigeration appliance (1) according to claim 6, characterized in that said first (37a) and second (37b) refrigerating panel comprise a channel (39) having an elongated cross-section, in particular hexagonal, for circulating a refrigerating fluid.
Refrigeration appliance (1) according to claim 1, characterized by comprising a refrigerator compartment (10), suitable for preserving fresh food, and a freezer compartment (20), suitable for preserving frozen food.
Refrigeration appliance (1) according to claim 9, characterized by comprising:
- a first intake duct (18) allowing the air to return to the refrigerating chamber (30) from the refrigerator compartment (10);

- a second intake duct (34) allowing the air to return to the refrigerating chamber (30) from the freezer compartment (20).