ITAN20100115A1 - NO-FROST REFRIGERATED REFRIGERATOR - Google Patents

Description

`` NO-FROST REFRIGERATOR PERFECTED ''

DESCRIPTION OF THE INVENTION

The present invention relates to a refrigerator for domestic use, in particular of the type without frost formation, also known as no-frost.

More specifically, the subject of the invention is a frost-free refrigerator capable of storing food and products of any kind without substantial loss of their quality.

The invention therefore fits into the household appliances sector, in particular that of domestic-type frost-free refrigerators.

As is known, in frost-free refrigerators heat is removed from food and products to be stored by forced convection, through a circulation of cold air in its internal compartment; this feature distinguishes frost-free refrigerators from those defined as â € œstaticâ €, ie without forced convection.

Another difference between frost-free and static refrigerators is the different defrosting mode which occurs electronically in the former while it is generally manual in the latter.

According to the state of the art, refrigerators are equipped with one or more internal compartments with different temperatures for the storage and preservation of food and products of various kinds (hereinafter, for clarity, collectively referred to as â € œfoodsâ €): in particular, a refrigerator compartment suitable for storing fresh food at a temperature between 0 ° C and 10 ° C and a freezer compartment, smaller in size and volume than the first, for storing frozen products. Depending on the relative position of these compartments, these refrigerators are divided into â € œcombinedâ € and â € œdouble doorâ €. Each compartment can also include several compartments, shelves and / or drawers. For the sake of clarity, during the description the term refrigerator (no-frost) will always be used regardless of the number of internal compartments and the type.

As is known, the no-frost ventilated refrigerators have an evaporator, generally lamellar, for cooling and drying the air and a fan for moving it inside one or more compartments. These components are generally huddled behind the rear wall of at least one of the refrigerator compartments while several holes made on it allow the inlet and subsequent circulation of the cooled air flow between the various shelves (provided that they are not clogged with food). Given the notoriety of frost-free refrigeration appliances, it does not seem necessary, at this level, to elaborate further on the multiple installation possibilities of their evaporator.

The main drawback of frost-free refrigerators is the formation of frost on the evaporator. As is known, in fact, inside the refrigerator there is generally a considerable amount of humidity due both to the entry of air from the outside (for example, when opening the door) and to the inevitable transpiration process of fresh food to be cooled and stored; therefore, during the cooling of the air, the humidity collected frost accumulates on it in the form of ice. The formation of ice on the lamellar evaporator leads to a penalization of the heat exchange due to its insulating properties and to a fluid dynamic inefficiency, as the passage of air is increasingly obstructed by the formation of frost. Therefore, in general, there is less cooling of the air flow and a consequent lower efficiency of the refrigerator. In the most serious cases, the formation of frost can also lead to the breaking of the evaporator compromising, in particular, the coupling between its fins (destined to increase the heat exchange surface) and the coil crossed by the refrigerant fluid.

A `` virtuous '' use of the refrigerator, avoiding, for example, frequent opening of its door or the introduction of hot food, helps to limit the supply of heat and humidity and, therefore, to contain consumption and the formation of frost on the € ™ evaporator, but this drawback cannot be eliminated, however, because it is congenital with the very concept of refrigeration in environments with a certain degree of humidity. It is generally managed by evaporator defrost systems which intervene automatically and at fixed time intervals. Known defrosting systems are, for example, those that provide for the inversion of the refrigeration cycle and / or the use of electrical resistances placed in correspondence with the evaporator. It is evident that the energy used for the transformation of humidity into frost as well as that used to melt the frost itself (especially in the case of electric heaters) constitutes a waste that greatly affects energy efficiency and consumption of the refrigeration apparatus.

A second major disadvantage of frost-free refrigerators concerns the risk that foods, especially `` fresh '' ones (vegetables, fruit and the like), if not protected by films or containers, can dry out excessively, losing their organoleptic and nutritional properties due to the air circulation activated. In fact, fresh foods normally have a very high humidity value and therefore on their surface there is a relative humidity of the air of the order of 90-95%. Therefore, in the compartment where these foods are stored, a relative humidity should be maintained at least equal to this value to prevent the water from evaporating from their surface while the air exiting the evaporator, having transferred the its humidity in the form of frost, is essentially dry.

To limit this inconvenience, systems for re-humidifying the cold and dry air coming from the evaporator have been planned for some time. Without losing generality, these systems can consist of trays, made on the bottom of the refrigerator compartment, designed to collect and contain part of the condensation water formed during the automatic defrosting process of the evaporator and capable of being lapped by the flow cold air. In this regard, see document ITI 104915 and / or document EP 0336 810.

The presence, inside the refrigerator compartment, of trays with stagnant water can, however, lead to problems of an aesthetic and hygienic nature, especially if the food accidentally ends up in contact with it.

Furthermore, the totality of the refrigerated air flow from the evaporator is unlikely to touch the surface of the water contained in said tray, making it difficult to maintain the ideal degree of humidity throughout the compartment in which the food is stored.

A similar solution is also reported in the document JP 2 238280 where said â € œpansâ € are however positioned in correspondence with the evaporator.

As an alternative to these trays, â € œmatsâ € capable of absorbing said condensation water and re-humidifying the dry air, coming from the evaporator, which passes through or laps them can be used. Said mats, described for example in document WO 93/14360, do not, however, solve the aforementioned problems of a hygienic nature.

Reference is also made to the defrosting and re-humidification systems of the cooled and dry air reported in documents US 3455 119 and / or US 4 075 866 although these solutions involve a considerable structural complication of the entire refrigerator appliance (providing , for example, paths and / or compartments dedicated to the re-humidification of the air).

The purpose of the present invention is to eliminate at least part of the problems described above.

In particular, the main purpose of the present invention is to indicate a frost-free refrigerator equipped with improved means for maintaining the properties and characteristics of the foods stored therein even for long periods.

A second purpose of the present invention is to indicate a frost-free refrigerator characterized by high energy efficiency and low consumption.

A further purpose of at least some variants of the present invention is to indicate an improved frost-free lighting system for the compartments of the refrigerator with reduced energy consumption and high aesthetic and commercial value.

These objects and other advantageous results, as will be clear, are achieved with a device conforming to the provisions of the main appended claims.

The characteristics of the present invention will be better highlighted by the following description of some preferred embodiments, according to the patent claims and illustrated, purely by way of non-limiting example, in the attached drawing tables, in which:

- Figure 1 schematically shows a side sectional view of a frost-free refrigerator according to a first embodiment of the invention and an enlargement of a detail thereof.

- Figure 2 shows, schematically, a side sectional view of a frost-free refrigerator according to a second form of the invention and an enlargement of a detail thereof

- figures 3 a and 3b respectively show, in axonometry and exploded view, a view of the evaporator unit of the no-frost refrigerator of figures 1 and / or 2.

- Figures 4 and 5 show, in two different views, the lighting system applied to the evaporator unit of the previous figures. The characteristics of the invention are now described, using the references contained in the attached figures.

With reference to figures 1 and 2, 1 indicates a frost-free refrigerator in the single-door and double-door types respectively. From here on, for the sake of simplicity, the term refrigerator will always be understood as a no-frost type refrigerating appliance.

The cabinet 11 of the refrigerator 1 is shown, obtained by thermoforming, within which one or more compartments 12, 13 are defined, comprising a plurality of shelves 14 on which the food to be stored can be placed.

As is known, food can also be stored in sliding drawers 15 or in cells closed by flap doors (not shown in the attached figures).

The compartments 12, 13 are accessible from the outside through the relative doors 12.a, 13.a. More specifically, the refrigerator 1 of figure 1 has a single door 12 to close the single compartment 12 in which to store food and fresh products (called refrigerator compartment 12) while figure 2 shows a refrigerator 1 comprising , in addition to said refrigerator compartment 12, a second compartment 13 (said freezer compartment 13) for storing frozen and / or deep-frozen products, also equipped with relative access door 13.a.

As already mentioned in part, the preservation of the organoleptic and nutritional properties of the foods stored inside the refrigerator 1 is entrusted to the circulation of a flow of suitably cooled air capable of cooling the food by forced convection, lapping them.

The cooling of the air flow and its circulation are entrusted to an “evaporator unit 2”.

The evaporator unit 2 comprises, in accordance with the known art, a fan 21 (preferably centrifugal and associated with a motor, not shown) and a lamellar evaporator 22 (also called finned coil) into which it is forced to pass, pushed by the fan 21 , the flow of air to be refrigerated.

As clearly shown in figs. 3a and / or 3b, fan 21 and evaporator 22 are positioned on a platform 23 to which a backrest 24 is connected, the function of which will be explained later, lying on a vertical plane substantially orthogonal to that of the platform 23 itself.

More in detail, as shown in figs. attached, on the platform 23 near its front edge 231 there is a housing for the centrifugal fan 21 while the lamellar evaporator 22 is positioned at the opposite rear edge 233. Between the centrifugal fan 21 and evaporator 22 is, moreover a distributor 25 is provided which uniformly distributes the flow of air sucked in by the fan 21 from the refrigerator compartment 12 over the entire exchanging surface of the evaporator 22 for optimum cooling thereof. The distributor 25 of figure 3a and / or 3b consists of fins 251 which depart from the hub 211 of the fan 21 defining a plurality of distribution channels 252 between them and with the aforementioned front edge 231 of the platform 23.

The centrifugal fan 21 is hidden from view by means of a cover 3 fixed to the external face 232 of the platform 23 and equipped with a protection grille 31 and with possible low consumption light points 32 (preferably LED).

According to the invention, the evaporator unit 2 is positioned and fixed, by known means and systems (for example, by screwing), inside the refrigerator compartment 12 in such a way that the floor 23 (and the components on placed thereon) is placed against the ceiling 111 of the refrigerator compartment 12 and the backrest 24 against its rear wall 112.

As shown in fig. 5 in section according to a horizontal plane, the width LS of the backrest 24 is smaller than that LP of the rear wall 112 so as to leave a passage 5 between its lateral edges and the sides 113 of the refrigerator compartment 12 (o, which is equivalent, of cabinet 11) for the reasons that will be understood below.

The backrest 24 and its longitudinal profiles 244 form with the rear wall 112 of the refrigerator compartment 12 a channel C.

During the programmed defrosting of the ice accumulated, for the reasons already seen, on the evaporator 22, the ducting C is able to convey the generated water towards a drainage 16 for its discharge (generally made on the rear wall 112 of the compartment refrigerator 12 near the cavity 17 which houses the compressor and other known components of the refrigeration circuit) while during full operation of the refrigerator 1 it acts as a plenum designed to receive the flow of cold air coming from the evaporator 22 and from which, pushed by the fan 21, is capable of passing back into the refrigerator compartment 12. From said plenum C, in fact, the air flow first passes through the holes 245 (see fig. 5) of the longitudinal profiles 244 and then the aforementioned steps 5 actually entering the refrigerator compartment 12. AHâ € ™ inside the refrigerator compartment 12, in other words, the air circulation is activated, indicated by the arrows FI in the attached figures .

According to the invention, the surface of the inner face 243 of the backrest 24 also has characteristics such as to allow part of that defrosting water, conveyed by gravity towards the drainage 16, to be retained thereon. This aptitude of the internal face 243 of the backrest 24 to remain wet can be obtained in various ways: by way of example and without any limiting intent, by providing on said internal face 243 notches and / or stylings and / or grooves and / or embossing and / or felts and / or any other system and means suitable for making the surface of said internal face 243 of said backrest 24 sufficiently rough to retain the defrosting water making it wettable and / or hygroscopic.

The cold and dry air coming from the evaporator 22 and which fills the plenum C during the normal operation of the refrigerator 1, is therefore susceptible to be loaded with humidity by licking the wet surface of said internal face 243 of the backrest 24.

By acting appropriately, in the design phase, on the surface dimensions of the backrest 24 and / or on the type and surface characteristics of its internal face 243, or on the quantity of water that it is able to retain, it can therefore be ensured in the refrigerator compartment 12 the level of humidity necessary to avoid excessive drying of the food, guaranteeing its correct conservation.

In addition to what has been said, it is useful to specify that, according to a preferred form of the invention, deflectors 242 can be provided on the internal face 243 of the backrest 24 which direct the flow of cold air towards the holes 245 of the longitudinal profiles 244 . Said deflectors 242 can be fixed or motorized, in the latter case being able to vary their orientation (controlled for example by the control and management unit of the refrigerator 1) to direct a greater fraction of cold air towards some shelves 14 of the refrigerator compartment. 12 rather than in others, for example towards those in which a faster cooling of food is required.

With the evaporator unit 2 just described, a second important advantage is also achieved. According to the invention, in fact, the defrosting of evaporator 22, which occurs following the temporary and programmed interruption of the refrigeration cycle, occurs naturally simply by being placed inside the refrigerator compartment. 12 where, as is known, the temperatures for food storage are largely positive, generally between 3 ° C and 10 ° C. However, nothing prevents the possibility of including one or more electric resistances (or similar heating devices) in correspondence with the evaporator 22 capable of accelerating defrosting.

According to another aspect of the invention, suitable seats 241 are made along the lateral sides of the backrest 24 for the installation of a lighting system 4 of the refrigerator compartment 12 (see Figures 4 and 5).

More specifically, the lighting system 4 consists preferably of luminous LED or SMD bars which, once installed on the seats 241, illuminate the aforementioned passages 5 between the backrest 24 and the sides of the wardrobe 11. For descriptive simplicity, see here on, the term LED will also indicate the so-called luminous SMDs.

As shown in Figure 4, several sectors 41, 42 can be identified on the light bars 4, each of which is capable of emitting light of different colors.

Purely by way of example and without any limiting intent, the light bar 4 can provide first sectors 41 whose LEDs emit light with substantially neutral or warm colors (preferably white or red) and second sectors 42 which emit cold light, preferably blue. Light bars 4 thus conceived therefore have the dual function of allowing adequate lighting of the refrigerator compartment 12 and, at the same time, of signaling, by means of the color of the light emitted, the different temperatures that can be found inside it. shelves 14.

Thus, said first sectors 41 will be positioned in correspondence with those shelves 14 (and / or drawers 15) which are located in the areas of the refrigerator compartment 12 with higher temperatures, while the second sectors 42 in correspondence with those located in the lower temperature areas (think, for example, of the well-known â € œfast coolingâ € compartments comprising one or more shelves 14).

It has also been seen how, according to the invention, the temperatures of said areas of the refrigerator compartment 12 can be varied, increasing or decreasing them, depending respectively on the greater or lesser flow of cold air that is directed there by the deflectors 242 motorized and adjustable backrest 24.

For this reason, each sector 41 and / or 42 of the light bar 4 can comprise both LED LI capable of emitting neutral / warm light and LED L2 which instead emit cold light, the former activating when the temperature of the refrigerator compartment area 12 It is higher than a predetermined threshold value in seconds when it is lower. The alternative switching on of the LI or L2 LEDs can therefore be automatically subjected (by the refrigerator control and command unit 1) to the variation of the orientation of the motorized deflectors 242.

It is clear that numerous variants of the refrigerator 1 object of the invention are possible for the man of the art, without thereby departing from the areas of innovation inherent in the inventive idea, just as it is clear that in the practical implementation of the In the invention, the various components previously described may be replaced by technically equivalent elements. For example, in the case of double door refrigerators 1, the evaporator unit 2 installed, as already fully described, in the refrigerator compartment 12 is also used for cooling a flow of air destined for the freezer compartment 13. In this variant, according to the usual fixed balancing methods (on which it is not essential to dwell on it being known to the expert in the art), the flow of air sucked by the fan 21 from the refrigerator compartment 12 and cooled by the evaporator 22 is , then, partly pushed along the back 24 and from this back to the refrigerator compartment 12 for storing fresh food and partly to the freezer compartment 13 (where much lower temperatures are required, of the order of - 20-25 ° C for their conservation). For this purpose, on the wall 112 of the cabinet I I, rear of the freezer compartment 13, there is an insulated duct 131 for the transport of the refrigerated air from the evaporator 22 to the freezer compartment 13 itself while the separation partition 114 with the refrigerator compartment 12 there is a return duct 132, also insulated, which brings the refrigerated air (according to the direction of the arrows F2) downstream of the fan 21 for a new cooling of the evaporator 22.

Obviously, nothing prevents the possibility of equipping the freezer compartment 13 with a dedicated and independent fan-evaporator unit with respect to the one installed in the refrigerator compartment 12.

It is clear that with a frost-free refrigerator 1 as described in its variants, the intended purposes are achieved, in particular that of avoiding excessive â € œdryingâ € of food and stored products while maintaining the flow of refrigerated air. which circulates in the refrigerator compartment 12, constantly humid by means of the backrest 24 of the invention and a considerable energy saving due to the possibility of carrying out the automatic and programmed defrosting of the evaporator 22 without the need for additional heating elements (in particular electric resistances ). It should also be noted that the accessory lighting system 4, which uses low energy consumption lighting means, can be easily mounted in the backrest 24 according to the invention, while it would be more problematic and expensive to assemble it if said backrest 24 were absent. The lighting system 4 also allows a more efficient use of the refrigerator 1 by signaling, with the different colors of the light emitted, the different internal temperatures so that the user can safely store the food, according to their characteristics and properties. organoleptic, on the right shelf 14 or drawer 15 ensuring optimal conservation.

Claims (1)

CLAIMS Riv 1) Refrigerator (1), in particular no-frost type, comprising inside its cabinet (11) a refrigerator compartment (12) or a refrigerator compartment (12) and a freezer compartment (13) for storing food and an evaporator unit (2; 21, 22, 23, 24, 25) in turn comprising: - an evaporator (22) - a fan (21) said evaporator (22) being able to cool the air moved inside said refrigerator compartment (12) and / or freezer compartment (13) by said fan (21) characterized by the fact that - said evaporator (22) is housed on a platform (23) to which a backrest (24) is connected, said backrest (24) being leaning against the rear wall (112) of said refrigerator compartment (12). - said backrest (24) forms with its longitudinal profiles (244) and with said rear wall (112) a channel (C), said channel (C) being - communicating with said evaporator (22). - a conveyor (C) for the defrosting water of said evaporator (22) - a plenum (C) suitable for receiving the cooled air from said evaporator (22) and coming from it - the surface of the internal face (243) of said backrest (24) provides means for retaining part of said defrosting water making it wettable and / or hygroscopic, said internal face (243) of said backrest (24) by filling the ™ air, cooled and coming from said evaporator (22), which touches it. Riv 2) Refrigerator (1) according to the preceding claim characterized by the fact that the quantity of said defrosting water that said internal face (243) of said backrest (24) is capable of retaining is defined in the design phase by acting on the dimensions of said internal face (243) and / or on the types and characteristics of said means of said backrest (24) adapted to retain part of said defrosting water. Riv 3) Refrigerator (1) according to any preceding claim characterized in that said conveyor (C) is in communication with a drain (16) for the discharge of said defrost water. Riv 4) Refrigerator (1) according to any preceding claim characterized in that said backrest (24) has a width (LS) smaller than the width (LP) of said rear wall (112) of said refrigerator compartment (12), between the lateral edges of said backrest (24) and the sides (113) of said compartment refrigerator (12) defining passages (5) for the passage of the air, leaving said plenum (C) through openings (245) on said longitudinal profiles (244), towards said refrigerator compartment (12). Riv 5) Refrigerator (1) according to any preceding claim characterized in that said means of said inner face (243) of said backrest (24) adapted to retain part of said defrost water consist of: scratches and / or streaks and / or grooves and / or embossing and / or felts fixed on said inner face ( 243) of said backrest (24) and / or any other system and means suitable for making the surface of said inner face (243) of said backrest (24) sufficiently rough to make it wettable and / or hygroscopic. Riv 6) Refrigerator (1) according to any preceding claim characterized in that on said internal face (243) of said backrest (24) deflectors (242) are provided which are suitable for directing the air cooled by said evaporator (22) and received in said plenum (C) towards said openings (245) of said profiles longitudinal (244). Riv 7) Refrigerator (1) according to the preceding claim characterized by the fact that said deflectors (242) are provided with motorized means which can vary their orientation. Riv 8) Refrigerator (1) according to any preceding claim characterized in that said fan (21) is placed near the front edge (231) of said platform (23) while said evaporator (22) is substantially placed in correspondence with the opposite rear edge (233) of said platform (23). Riv 9) Refrigerator (1) according to any preceding claim characterized in that said platform (23) further comprises a distributor (25) adapted to uniformly distribute the air sucked in by said fan (21) over the entire exchanging surface of said evaporator (22), said distributor (25) being placed between said fan ( 25) and said evaporator (22) e | comprising a plurality of distribution channels (252) defined by said front edge (231) and by fins (251) which branch off from the hub (211) of said fan (21). Riv 10) Refrigerator (1) according to at least claim 8 characterized by the fact that said shelf (23) is placed close to the ceiling (11 1) of said refrigerator compartment (12). Riv 11) Refrigerator (1) according to at least claim 8 characterized in that said freezer compartment (13): - It communicates with said evaporator (22) through an insulated duct (131) made in the wall (112) of said cabinet (11) behind said freezer compartment (13), said duct (131) carrying part of the cooled air from said evaporator (22) into said freezer compartment (13), according to the usual fixed balancing methods, for storing frozen and / or deep-frozen foods; - It communicates with a return duct (132) obtained in the separation partition (114) of said freezer compartment (13) with said refrigerator compartment (12), said return duct (132) being able to bring back said part of the ™ air downstream of said fan (21) for a new cooling. Riv 12) Refrigerator (1) according to any preceding claim characterized in that lighting means (4) are housed on said backrest (23) with a signaling and / or aesthetic purpose.