Patent Description:
Refrigeration appliances of known types generally include an inner liner disposed within an outer cabinet. The inner liner typically defines one or more compartments, for example a fresh food compartment and a freezer compartment. Each compartment has an open front closed by a door pivotally mounted to the outer cabinet. Compartments are preferably provided with shelves and/or storage drawers to receive items therein.

A refrigeration system is provided to cool the compartments. The refrigeration system typically includes an evaporator for cooling down air.

A fan system is preferably arranged closed to the evaporator for creating a cooling air stream for the compartment/s. The air passes over the evaporator which cools the air passing therethrough and then a fan conveys the cooled air, coming from the evaporator, inside the compartment/s. Different known solutions are described in documents <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT> <CIT> and <CIT>.

Document <CIT> discloses a refrigeration appliance provided with all the technical features from the preamble of claim <NUM>.

The fan typically sucks cooled air coming from the evaporator and expels it towards the compartment/s.

In order to convey the expelled cooled air by the fan in different zones of the appliance, for example into two compartments or in different points in the same compartment, conveying channels are opportunely realized from the fan outlet to respective air paths. In known systems, for example, conveyance channels are preferably realized in a layer of plastic foam insulation material disposed closed to the fan outlet.

A nagging problem for manufacturers is to realize a system with good distribution of air between channels. Bad distribution of air usually causes undesirable noise during operation. In instances where the refrigeration appliance is a domestic refrigerator, the noise can be annoying to consumers and/or give the consumer the impression that the refrigeration appliance is poorly designed and/or poorly manufactured.

In particular, noise may be caused by high air speed and/or turbulent flow of air through the ducts. When air passes mainly through one channel or few channels only, the air speed resulting from the fan air flow is increased due to the small air passage cross section.

Another problem of the known systems in that fewer compartments and/or fewer zones in a compartment receive the needed cold air, affecting the average cooling efficiency of the appliance.

It is therefore an object of the invention to implement a system apt to enhance the smooth distribution of the cooled air compared to known systems.

It is another object of the invention to implement a system apt to reduce noise during operation of the air flowing into conveying channels.

It is a further object of the invention to implement a system apt to optimize the average cooling efficiency of the appliance.

It is another object of the invention to implement a system apt to reduce manufacturing time and/or costs compared to known systems taking care of efficiency and noise of the appliance.

The applicant has found that by providing a refrigeration appliance according to claim <NUM> having a compartment, a refrigeration system and a fan system for conveying cooled air to the compartment and by providing a first duct and a second duct joined at a partition wall for the conveyance of the cooled air wherein at least a portion of the cross-section of said partition wall shows a concave upward curve, it is possible to solve the drawbacks of the known systems.

The invention therefore relates to a refrigeration appliance according to claim <NUM> and comprising:.

As concave upward curve is intended a curve in an interval [a, b] wherein all points on the curve lie above the tangent to the curve at any point in said interval [a, b].

In the orthogonal coordinate system according to the invention, the point "a" corresponds to the origin and the point "b" is another point along the X-axis following the direction of rotation of the rotor.

According to a preferred embodiment of the invention, the fan system comprises a first opening between the first duct and the at least one compartment and a second opening between the second duct and the at least one compartment allowing the conveyance of the air expelled by the fan towards the at least one compartment.

According to the invention, therefore, at least a portion of the cross-section of said partition wall in said reference plane shows a concave upward curve, along its length towards said second opening, while moving from the origin towards positive values of said X-axis following said direction of rotation of the rotor.

A chamber for air expelled by the fan is defined around the fan and the ducts fluidically communicate with the chamber.

The air follows the concavely shaped curve and is distributed in a laminar way along the duct up to its final part and then into the compartment. The air is not directly/linearly directed towards the final part of the ducts.

Advantageously, noise during operation is reduced due to laminar air flowing into the duct.

In a preferred embodiment of the invention, the fan system comprises more than two ducts, wherein at least two adjacent ducts of said ducts define said first duct and said second duct.

Advantageously, by providing a plurality of ducts, preferably three or more ducts, arranged around the fan and by providing the partition walls with said concave curves, the air coming from the rotor is uniformly and/or smoothly conveyed among the ducts.

According to the invention, the rotor comprises at least one blade having a leading edge, a trailing edge and a chord line, wherein the distance between said origin and the circumference determined by the trailing edge during rotation of the rotor has a value higher than <NUM>,<NUM> times the length of the chord line.

The chord line goes from the leading edge to the trailing edge. The leading edge is the proximal edge of the blade with respect the rotation axis and the trailing edge is the distal edge of the blade with respect the rotation axis.

Preferably the rotor comprises a plurality of blades uniformly distributed around the rotation axis.

Preferably, the distance between said origin and the circumference determined by the trailing edge during rotation of the rotor has a value lower than <NUM> times the length of the chord line.

In a preferred embodiment of the invention, the first duct, along said reference plane, comprises a first lateral wall and a second lateral wall defining a respective path wherein air flows and/or the second duct, along said reference plane, comprises a first lateral wall and a second lateral wall defining a respective path wherein air flows.

Preferably, the first lateral wall of the first duct is provided upstream of the respective second lateral wall of the same first duct and/or the first lateral wall of the second duct is provided upstream of the respective second lateral wall of the same second duct, wherein the term upstream is considered with reference to the direction of rotation of the rotor.

According to a preferred embodiment of the invention, the concave upward curve is defined in the first lateral wall of the respective duct.

Preferably, the first lateral wall and the second lateral wall of the duct get closer in the direction of the air stream flow.

Advantageously, laminar air flowing through the duct is enhanced.

In a preferred embodiment of the invention, the second lateral wall is shaped to follow the shape of the first lateral wall. In other words, the second lateral wall is curved in the same direction of the first lateral wall.

According to a preferred embodiment of the invention, the first duct and the second duct are realized in a first layer receiving the fan.

In a preferred embodiment of the invention, the first layer comprises a seat to at least partially receive the fan.

Preferably, the first layer is a layer of expanded polystyrene.

In a preferred embodiment of the invention, the fan system comprises a fan assembly, preferably a pre-assembled assembly.

According to the invention, the refrigeration system comprises an evaporator to cool down air for the at least one compartment, the evaporator being preferably arranged inside the at least one compartment at a first wall thereof, the fan assembly being preferably arranged inside the at least one compartment and associated with the evaporator for generating a cooling air stream for the at least one compartment;.

Preferably, the fan assembly further comprises a second layer of expanded polystyrene arranged between the fan and the cover plate.

In a preferred embodiment of the invention, the first layer comprises said at least a first duct and at least a second duct and said cover plate comprises one or more air opening communicating with the first duct and the second duct when the fan assembly is assembled.

According to a preferred embodiment of the invention, the fastening device comprises snap fit elements.

Preferably, the fastening device comprises elastic tongues protruding from the cover plate interacting with recesses in the first layer.

According to a preferred embodiment of the invention, the fan assembly comprises a mounting element apt to mount the fan to the first layer.

Preferably, the fan comprises a frame apt to support the rotor.

In a preferred embodiment of the invention, the fan assembly further comprises a fan mouth where air flows from the evaporator to the fan.

According to a preferred embodiment of the invention, the fan mouth and the mounting element are integrally made.

Preferably, the refrigeration system further comprises connecting means apt to connect the fan assembly to the first wall of the compartment.

Further characteristics and advantages of the present invention will be highlighted in greater detail in the following detailed description of a preferred embodiment of the invention, provided with reference to the enclosed drawings. In said drawings:.

Referring to <FIG> a refrigeration appliance in accordance with claim <NUM> in the form of a domestic refrigerator is shown, indicated generally as <NUM>. Although the detailed description that follows concerns a domestic stand-alone refrigerator <NUM>, the refrigeration appliance can be embodied by refrigeration appliances other than a domestic refrigerator.

Furthermore, the embodiment described in detail below refers to a bottom mount refrigerator, i.e. of the type including a freezer compartment disposed vertically below a fresh food compartment. However, the refrigerator according to the invention can have any desired configuration, for example a top mount refrigerator wherein the freezer compartment is disposed vertically above the fresh food compartment or a refrigerator comprising only a fresh food compartment or only a freezer compartment.

Furthermore, while the present application is described with reference to a stand-alone refrigerator it has to be noted that also a built-in solution may be contemplated.

The refrigeration appliance <NUM> in accordance with claim <NUM> illustrated in the figures, hereinafter indicated as refrigerator <NUM>, comprises an outer cabinet <NUM> and an inner liner <NUM>, internally received in the outer cabinet <NUM>. The outer cabinet <NUM> and the inner liner <NUM> are separated by a spacing filled with thermal insulation <NUM>, preferably a foam insulation.

The outer cabinet <NUM> preferably extends in a vertical direction V and preferably comprises a base 2A suitable to lay on the ground, a roof 2B and lateral side walls 2C, 2D, 2E connecting the base 2A and the roof 2B, preferably two lateral side walls 2C, 2D and a rear side wall 2E.

In its installed position, lateral side walls 2C, 2D and the rear side wall 2E are preferably aligned to the vertical direction V.

The refrigerator <NUM> according to the embodiment shown in the figures preferably represents a bottom mount type refrigerator. At this purpose, a divider portion <NUM> (<FIG>) is provided which divides inner liner <NUM> into a lower space that is used as a freezer compartment <NUM>, and an upper space that is used as a fresh food compartment <NUM>.

The freezer compartment <NUM> substantially preferably has the form of a cuboid defining a rectangularly shaped front opening <NUM>. A door <NUM> is preferably pivotally mounted to the outer cabinet <NUM> and is movable between an open position and a closed position to cover the front opening <NUM>.

The freezer compartment <NUM> preferably shows a rear wall <NUM> which is defined by a portion of the inner liner <NUM>, more preferably a vertical rear wall <NUM>.

Analogously, the fresh compartment <NUM> substantially and preferably has the form of a cuboid defining a rectangularly shaped front opening <NUM>. A door <NUM> is preferably pivotally mounted to the outer cabinet <NUM> and is movable between an open position and a closed position to cover the front opening <NUM>.

In an alternative embodiment, a single door can be provided to open and close both the front openings <NUM>, <NUM> of the freezer and the fresh compartments <NUM>, <NUM>. The compartments <NUM>, <NUM> preferably comprise shelves S and/or drawers D for receiving food items.

A refrigeration system <NUM> is provided to cool the compartments <NUM>, <NUM>.

The refrigeration system <NUM> is apt to cool down air which is circulated inside at least one compartment of refrigerator <NUM>, preferably to cool down air which is circulated inside both compartments <NUM>, <NUM>.

In the preferred embodiment of the invention, the refrigeration system <NUM> preferably comprises a closed recirculating system filled with a suitable refrigerant, for example R12 or R134a. The refrigeration system preferably comprises an electric motor-driven compressor <NUM>, a condenser heat exchanger <NUM>, a pressure device such as a capillary tube or a thermostatic valve (not shown) and comprises an evaporator <NUM>.

A collecting tray <NUM> is preferably arranged below the evaporator <NUM> to collect water formed by condensation on the evaporator <NUM>.

The evaporator <NUM> is preferably mounted inside the freezer compartment <NUM>, whereas the compressor <NUM> is mounted external to the freezer compartment <NUM> and preferably arranged in a working chamber <NUM> at the bottom of the refrigerator <NUM>.

The condenser heat exchanger can be a condenser tubing <NUM> that preferably has a serpentine configuration and is preferably externally secured to the rear side wall 2E of the outer cabinet <NUM> so as to form what is commonly known as a "hot wall". Further features of the refrigeration system <NUM> are not described in detail in the present application since are well known in the art.

The evaporator <NUM> is more preferably mounted to the rear wall <NUM> of the freezer compartment <NUM> towards the interior of the freezer compartment <NUM>.

According to the invention, a fan system <NUM> is associated to the evaporator <NUM> for conveying the cooled air to different zones of the refrigerator <NUM>, as better described below.

In a preferred embodiment of the invention, as illustrated in the Figures, the fan system <NUM> comprises a fan assembly <NUM> arranged closed to the evaporator <NUM>. The fan assembly <NUM> is shown isolated from the rest in <FIG>. In a preferred embodiment of the invention, the fan assembly <NUM> is a pre-assembled assembly and is advantageously pre-assembled during manufacturing of the refrigerator <NUM> and then it is mounted inside the freezer compartment <NUM> over the evaporator <NUM>.

The fan assembly <NUM> is preferably connected to the rear wall <NUM> of the freezer compartment <NUM> through connecting means <NUM>.

In the preferred embodiment illustrated in the figures, the connecting means <NUM> preferably comprise two lower protruding tabs 61A, 61B with holes for receiving fixing screws (not shown). The fan assembly <NUM> is assembled to the freezer compartment <NUM> by inserting its upper part in position inside the freezer compartment <NUM>, rotating its lower part to bring the fan assembly <NUM> in its final position and finally fixing the fan assembly <NUM> to the inner liner <NUM> with screws inserted in the tabs 61A, 61B.

In different preferred embodiments, the connecting means may comprise other type of fasteners, such as mechanical (e.g. rivets, nuts and bolts, etc.), chemical (e.g. adhesive, epoxy, etc.), or other type of fasteners.

The function of the fan system <NUM>, and in particular of the fan assembly <NUM>, is to generate the cooling air stream that is conveyed and recirculated inside the freezer compartment <NUM> and, in the preferred embodiment here illustrated, also inside the fresh food compartment <NUM>. The fan assembly <NUM> is configured to draw air from the evaporator <NUM> and to expel it into different points of the freezer compartment <NUM> and into the fresh food compartment <NUM>.

The fan assembly <NUM> preferably comprises a first layer <NUM> of expanded polystyrene, a fan <NUM>, a second layer <NUM> of expanded polystyrene and a cover plate <NUM>.

The first layer <NUM>, the fan <NUM>, the second layer <NUM> and the cover plate <NUM> are preferably arranged side by side, i.e. arranged one laterally of the other and preferably in a lateral order perpendicular to the vertical direction V. In other words, each component <NUM>, <NUM>, <NUM>, <NUM> is at least partially stacked/in contact to the laterally adjacent component.

Preferably, expanded polystyrene used for the layers <NUM>, <NUM>, i.e. EPS, is a lightweight, rigid plastic foam insulation material made of solid polystyrene particles.

The use of EPS enhances thermal isolation of the fan assembly <NUM>, being EPS a high-quality thermal insulator material.

In addition, the use of EPS enhances acoustic isolation of the fan assembly <NUM>, in particular of noise caused by rotation of the fan <NUM> and of the air expelled from it. Furthermore, using of EPS simplifies the fan assembly <NUM> construction as EPS is an easily handled material. Still advantageously, EPS is a cheap material.

Therefore, manufacturing time and/or costs are reduced compared to known systems.

In a further preferred embodiment of the invention, not shown, the second layer of expanded polystyrene may be omitted.

The fan <NUM> comprises a rotor <NUM> with a rotation axis Z. The rotor <NUM> is preferably mounted on a supporting frame <NUM>.

The supporting frame <NUM> preferably has a spider shaped structure with arms 80A-80F supporting the rotor <NUM>, as visible in <FIG>.

The fan <NUM> preferably comprises a centrifugal fan, preferably a radial fan. The air flows from a suction side 72A of the fan <NUM> facing the evaporator <NUM>, and the air is then displaced radially, changing its direction (typically by <NUM>°). The rotor <NUM> preferably consists of a rotating arrangement of vanes or blades BL, rotating around said axis Z, which act on the air. Preferably, the rotor <NUM> comprises a plurality of blades BL uniformly distributed around the rotation axis Z.

Preferably, a fan mouth <NUM> is arranged at the suction side 72A of the fan <NUM> to convey the air from the evaporator <NUM> to the rotor <NUM>. The fan mouth <NUM> preferably faces the evaporator <NUM> and is preferably placed between the first layer <NUM> and the fan <NUM>.

In different preferred embodiments, the fan mouth may be omitted.

A suction chamber <NUM> is created between the fan <NUM>, preferably the fan mouth <NUM>, and the outlet side 38A of the evaporator <NUM>, as shown in <FIG>. The fan <NUM> draws air from the evaporator <NUM> through the suction chamber <NUM> and expels it outside the fan assembly <NUM>, towards the freezer compartment <NUM> and the fresh food compartment <NUM>, as better described later.

The air preferably flows in the compartments <NUM>, <NUM> to define closed loop circuits and the fan <NUM> is switched on/off according to operational condition, for example the temperature level inside the compartments <NUM>, <NUM> and/or opening of the doors, etc..

The rotating axis Z of the rotor <NUM> is preferably inclined with respect to a vertical direction V.

Preferably, the rotating axis Z is inclined with respect to the rear side wall 2E of the outer cabinet <NUM>.

The rotating axis Z is preferably inclined with respect to the vertical direction V of an angle W comprised between <NUM>° and <NUM>°, more preferably inclined of an angle W equal to <NUM>°.

Advantageously, by inclining the rotor <NUM> with respect the vertical direction V the suction chamber <NUM> is shaped to guarantee a good fluid dynamics efficiency and at the same time the space occupied by the fan <NUM> is minimized so that the volume of the freezer compartment <NUM> is not negatively affected.

In different embodiments, nevertheless, the rotating axis of the rotor may have any different inclination with respect to the vertical direction.

The fan assembly <NUM> preferably comprises a fastening device <NUM> apt to fasten the cover plate <NUM> to the first layer <NUM> to keep elements of the fan assembly <NUM> in the assembled configuration.

Preferably, the fastening device <NUM> is apt to fasten the cover plate <NUM> to the first layer <NUM> to keep staked, preferably in the following order, the first layer <NUM>, the fan <NUM> and the second layer <NUM> in their assembled position.

The fastening device <NUM> keeps the elements of the fan assembly <NUM> firmly together. In particular, preferably, the fan <NUM> is firmly sandwiched between the layers <NUM>, <NUM> of expanded polystyrene EPS.

In case the second layer of expanded polystyrene is omitted, according to an alternative preferred embodiment of the invention, the fastening device is apt to fasten the cover plate to the first layer to keep staked, preferably in the following order, the first layer and the fan in their assembled position.

Preferably, the fastening device <NUM> comprises snap fit elements. In the preferred embodiment illustrated in the figures, the fastening device <NUM> comprises elastic tongues <NUM> protruding from the cover plate <NUM> which interact with respective recesses <NUM> in the first layer <NUM>, as better illustrated in <FIG>. Tongues <NUM> are preferably made in one piece with the cover plate <NUM> to realize a single body.

Advantageously, the fan assembly <NUM> with associated fastening device <NUM> guarantees a compact configuration that avoids/reduces vibrations between them, in particular during activation of the fan.

This results in a reduction of noise during operation of the refrigerator <NUM> and/or also an improved reliability of the refrigerator.

Furthermore, advantageously, the fastening device and the cover plate realize a single body so that there is no need of separated fastening means, thus reducing complexity of the fan assembly and simplifying assembling process steps.

According to an aspect of the invention, the first layer <NUM> comprises one or more air conveying channels 40a-<NUM>, or ducts, for conveying cooled air expelled from the fan <NUM> towards the compartments <NUM>, <NUM>.

A chamber <NUM> for air expelled by the fan is therefore defined around the fan <NUM> itself. The ducts 40a-<NUM> fluidically communicate with the chamber <NUM>.

The ducts 40a-<NUM>, as illustrated in <FIG> and <FIG>, are opened in the direction of the cover plate <NUM>. In the assembled configuration, then, the cover plate <NUM> opportunely closes the ducts 40a-<NUM> allowing the air conveyance. The first layer <NUM> with open channels 40a-<NUM> are easily obtained through an injection mould process with EPS.

Nevertheless, in a further preferred embodiment (not shown) ducts may be realized as closed ducts directly on the first layer.

According to the preferred embodiment illustrated in the figures, there are six ducts 40a-40f that are radially arranged around the fan <NUM> for the air to the freezer compartment <NUM> and an upper duct <NUM> for the air to the fresh food compartment <NUM>.

The cover plate <NUM> preferably comprises one or more air opening 102a-102f communicating with the air conveying channels 40a-40f of the first layer <NUM>. Cooled air advantageously enters the freezer compartment <NUM> through said air openings 102a-102f, which preferably are grated openings. It is preferably contemplated that the cover plate <NUM> is made from plastic to provide an aesthetically pleasing appearance to a user.

Generally, the fan system comprises openings between the ducts and the freezer compartment allowing the conveyance of the cooled air expelled by the fan towards the freezer compartment through the ducts.

Preferably, an intermediate sheet <NUM> is interposed between the firs layer <NUM> and the cover plate <NUM>. The intermediate sheet <NUM> preferably comprises holes 106a-106f aligned with the air openings 102a-102f of the cover plate <NUM>.

The intermediate sheet <NUM> enhances the closure of the ducts 40a-<NUM> of the first layer <NUM>. The intermediate sheet <NUM> improves the sealing effect for the ducts 40a-<NUM>, in particular in case the cover plate <NUM> is not perfectly planar.

In a further preferred embodiment, the intermediate sheet may be omitted.

Preferably, the first layer <NUM> comprises a seat <NUM> apt to at least partially receive the fan <NUM>.

A mounting element <NUM> is preferably used to mount the fan <NUM> to the first layer <NUM>, preferably to the seat <NUM>. More preferably, the mounting element <NUM> is preferably used to mount the frame <NUM> of the fan <NUM> to the first layer <NUM>.

In the preferred embodiment illustrated in the figures, the mounting element <NUM> is integrally made with the fan mouth <NUM>. Manufacturing time and/cost are advantageously reduced.

In different preferred embodiments, nevertheless, the mounting element and fan mouth can be two independent elements.

The mounting element <NUM> is arranged in the seat <NUM> of the first layer <NUM> and connected thereto. In the preferred embodiment illustrated in the figures the mounting element <NUM> preferably comprises an annular surface 124A that preferably lays in a plane perpendicular to the axis Z of the rotor <NUM>.

The mounting element <NUM> preferably comprises one or more pins <NUM> apt to be inserted in respective one or more through holes <NUM> of the first layer <NUM>. The pins <NUM> preferably protrude from the annular surface 124A of the mounting element <NUM>.

The pins <NUM> are axially blocked to the first layer <NUM> with blocking elements <NUM>, for example internal tooth lock washers, connected at the tip of the pins <NUM> and abutting a surface <NUM> of the first layer <NUM>, as better visible in <FIG>. The pins <NUM>, allow the constraint of the mounting element <NUM> to the first layer <NUM>.

More preferably, the frame <NUM> of the fan <NUM> is connected to the mounting element <NUM> through a carrier structure <NUM> preferably comprising ribs <NUM> protruding from the annular surface 124A of the mounting element <NUM>.

In the preferred embodiment illustrated, the ribs <NUM> define connecting points for the frame <NUM> of the fan <NUM>, preferably three connecting points (<FIG>).

Vibration dampening elements <NUM> are preferably interposed between the fan <NUM> and the mounting element <NUM>. Preferably, the vibration dampening elements <NUM> are interposed between the frame <NUM> of the fan <NUM> and the mounting element <NUM>. More preferably the vibration dampening elements <NUM> are interposed between the frame <NUM> of the fan <NUM> and the carrier structure <NUM> of the mounting element <NUM>.

Vibration dampening elements <NUM> preferably comprise rubber washers interposed between three arms 80A, 80C, 80E of the supporting frame <NUM> and corresponding ribs <NUM> of the mounting structure <NUM>.

Vibration dampening elements <NUM> advantageously absorb vibrations created by the fan rotation.

In a preferred embodiment of the invention, the second layer <NUM> comprises a seat/opening <NUM> apt to at least partially receive the fan <NUM>.

The second layer <NUM>, then, preferably comprises protruding pins 222a apt to be received in respective holes 222b of the first layer <NUM> when the fan assembly <NUM> is assembled.

In the assembled configuration, the second layer <NUM> of EPS enhances acoustic isolation of the noise caused by rotation of the fan <NUM> towards the internal volume of the freezer compartment <NUM>.

As said above, the air preferably flows in the compartments <NUM>, <NUM> to define closed loop circuits. Advantageously, the fan assembly <NUM> create an air flow paths inside the fresh food compartment <NUM> and air flow paths in the freezer compartment <NUM>, schematically indicated with FF, F1, F2, F3 in <FIG> and <FIG>.

In particular, air flow path FF is generated by the fan assembly <NUM> and conveyed to the fresh food compartment <NUM> through the upper duct <NUM> of the first layer <NUM>. Air flow paths F1, F2, F3 are generated by the fan assembly <NUM> and conveyed to the freezer compartment <NUM> through the six ducts 40a-40f of the first layer <NUM> and air openings 102a-102f of the cover plate <NUM>.

From the inside of the freezer compartment <NUM>, then, the air flows back to the evaporator <NUM> through a gap <NUM> preferably defined between the lower part of the cover plate <NUM> and the lower part of the rear wall <NUM> of the freezer, as indicated in <FIG>.

According to an aspect of the invention, as illustrated in particular in <FIG>, the ducts 40a-40f are preferably arranged in couples around the fan <NUM> for the conveyance of the air expelled by the fan <NUM> towards two respective paths.

The couple of ducts 40a-40f are joined at a partition wall <NUM>-<NUM>.

In particular, according to the preferred embodiment illustrated in the Figures, the ducts 40a-40f define:.

Each duct 40a-40f preferably shows two opposite lateral walls, namely a first lateral wall 45a-45f and a second lateral wall 46a-46f.

The first lateral wall 45a-45f of each duct 40a-40f is provided upstream of the respective second lateral wall 46a-46f of the same duct 40a-40f, wherein the term upstream is considered with reference to the direction of rotation D of the rotor <NUM>.

Air flows in respective path defined in each duct 40a-40f by the first and the second lateral wall 45a-45f, 46a-46f.

Partition walls <NUM>-<NUM> extend from a first lateral wall 45a-45f of a first duct 40a-40f and a second lateral wall 46a-46f of an adjacent second upstream duct 40a-40f, wherein the term upstream is considered with reference to the direction of rotation D of the rotor <NUM>.

In alternative preferred embodiments, different numbers of couple of ducts may be provided, for example just one couple of ducts or more than five couple of ducts.

Firstly, for the scope of the present invention, a reference plane orthogonal to the rotation axis Z of the rotor <NUM> is considered. Plan views of <FIG> are views according to said reference plane.

Also, by considering said reference plane, an orthogonal coordinate system is defined for each couple of said ducts 40a-40f. Therefore, in the preferred embodiment illustrated in <FIG>, five orthogonal coordinate systems are defined.

Each orthogonal coordinate system is defined as follows:.

According to the invention, at least a portion 44b-44f of the cross-section of the partition walls <NUM>-<NUM> in the reference plane shows a concave upward curve while moving from the origin O1-O5 towards positive values of the X-axis following the direction of rotation D of the rotor <NUM>.

At least a portion 44b-44f of the cross-section of the partition walls <NUM>-<NUM> in the reference plane shows a concave upward curve, along its length towards the openings 102a-<NUM>, while moving from the origin O1-O5 towards positive values of the X-axis following the direction of rotation D of the rotor <NUM> In other words, the first portion 44b-44f of the first wall 45a-45f of a duct 40a-40f is a concavely shaped curve.

In the orthogonal coordinate system according to the invention, the point "a" corresponds to the origin O1-O5 and the point "b" is another point along the X-axis following the direction of rotation D of the rotor <NUM>, as exemplary indicated only for the third orthogonal coordinate system O3, X3, Y3 in <FIG>.

Applicant has recognized that by shaping the first portion 44b-44f of the first wall 45a-45f of a duct 40a-40f as a concave upward curve, the air coming from the rotor <NUM> is more smoothly conveyed into the ducts 40a-40f.

The air expelled by the rotor <NUM>, as schematically illustrated in <FIG>, flows through each duct 40a-40f in order to reach the respective final part and then to reach the air opening 102a-102f of the cover plate <NUM>.

According to an aspect of the invention, the air follows the concavely shaped curve 45a-45f and is advantageously distributed in a laminar way along the duct 40a-40f up to its final part. The air is not directly/linearly directed towards the final part of the duct 40a-40f.

Advantageously, noise during operation is reduced due to laminar air flowing into the ducts 40a-40f.

Preferably, the second wall 46a-46f of the duct 40a-40f opposite the first wall 45a-45f is shaped to substantially follow the shape of the first wall 45a-45f, as it can be appreciated in particular with reference to third, fourth, fifth and sixth ducts 40c-40f. In particular, by watching the ducts 40c-40f as in the plane view of <FIG>, the second walls 46c-46f of the ducts 40c-40f are curved in the same direction of the respective first walls 45c-45f of the duct 40c-40f, for example the second wall 46c and the first wall 45c of the third duct 40c are both slightly curved to the right.

Preferably, in the direction of the air stream flow, the duct 40a-40f narrows, i.e. the first wall 45a-45f and the second wall 46a-46f get closer following the air stream flow, i.e. going towards the final part of the duct 40a-40f. Narrowing of the ducts 40a-40f enhances an efficient laminar air flowing through the ducts 40a-40f and air openings 102a-102f.

Still advantageously, by providing a plurality of ducts 40a-40f, preferably three or more ducts 40a-40f, arranged around the fan <NUM> and by providing partition walls <NUM>-<NUM> joining two adjacent ducts 40a-40f having concave curves 44b-44f as described above the air coming from the rotor <NUM> is uniformly and/or smoothly conveyed among the ducts 40a-40f.

Preferably, when the air encounters the concave curves 44b-44f of partition walls <NUM>-<NUM> is subjected to a localized pressure drop that facilitates the uniform distribution of air among all the ducts 40a-40f and, eventually, uniform distribution of air inside the freezer compartment <NUM> through air openings 102a-102f of the cover plate <NUM>. The average cooling efficiency inside the freezer compartment <NUM> is thus optimized.

According to the invention, the ducts 40a-40f are configured so that the partition walls <NUM>-<NUM> are arranged around the fan <NUM>, and around the rotor <NUM>, at optimized distances, as illustrated in <FIG>.

Firstly, for the scope of the present invention, the following elements are considered (see <FIG>):.

Then, the distances d1-d5 between the origins O1-O5 and the circumference C are considered.

According to the invention, all distances d1-d5 have a value higher than <NUM>,<NUM> times the length of the chord line CL.

Said relations indicate that the partition walls <NUM>-<NUM> are arranged around the fan <NUM> above a minimum distance from the trailing edge Te of the blades BL of rotor <NUM>, when the rotor <NUM> rotates. The minimum distance allows to keep low the noise of the air expelled by the fan and striking the partition walls <NUM>-<NUM>.

According to another aspect of the invention, at least one distance d1-d5 among the distances d1-d5 preferably has a value lower than <NUM> times the length of the chord line CL, i.e.:
d1<<NUM>*CL or d2<<NUM>*CL or d3<<NUM>*CL or d4<<NUM>*CL or d5<<NUM>*CL.

Preferably, more than one distance d1-d5 among the distances d1-d5 preferably have a value lower than <NUM> times the length of the chord line CL.

More preferably, all distances d1-d5 preferably have a value lower than <NUM> times the length of the chord line CL.

Said relations indicate that the partition walls <NUM>-<NUM> are preferably arranged around the fan <NUM> below a maximum distance, not too far, from the trailing edge Te of the blades BL of rotor <NUM>, in particular when the rotor <NUM> rotates. By arranging the partition walls <NUM>-<NUM> not too far around the fan <NUM>, the advantageous effect of the concave curves 44b-44f of partition walls <NUM>-<NUM> is positively maintained.

It has thus been shown that the present invention allows all the set objects to be achieved. In particular, it makes it possible to provide a refrigeration appliance with a fan system that enhances the smooth distribution of the cooled air compared to known systems.

It is underlined that in the refrigeration appliance illustrated in the enclosed figures, the ducts are preferably realized in the layer of expanded polystyrene which receives the fan. Nevertheless, in different preferred embodiments, the ducts which are arranged around the fan/rotor according to the invention may be realized in any different way. For example, the duct may be realized as a box-shaped structure formed of metal sheets joined together.

Claim 1:
A refrigeration appliance (<NUM>) comprising:
- at least one compartment (<NUM>) for receiving food items;
- a refrigeration system (<NUM>) for cooling down air and a fan system (<NUM>) configured to draw air from an evaporator (<NUM>) of the refrigeration system (<NUM>) for conveying the cooled air to said least one compartment (<NUM>);
wherein said fan system (<NUM>) comprises a fan (<NUM>) comprising a rotor (<NUM>) rotating in a direction of rotation (D) around a rotation axis (Z), at least a first duct (40a-<NUM>) and at least a second duct (40a-<NUM>) arranged around said fan (<NUM>) for the conveyance of the air expelled by said fan (<NUM>) towards said at least one compartment (<NUM>), said first duct (40a-<NUM>) and said second duct (40a-<NUM>) being joined at a partition wall (<NUM>-<NUM>);
wherein, by considering a reference plane that is orthogonal to said rotation axis (Z) of the rotor (<NUM>) and by considering an orthogonal coordinate system wherein:
- the origin (<NUM>-<NUM>) is the closest point of the partition wall (<NUM>-<NUM>) to said rotation axis (Z);
- Y-axis is the line laying in said reference plane and drawn from said rotation axis (Z) towards said origin (<NUM>-<NUM>);
- X-axis is the line laying in said reference plane and drawn from said origin (<NUM>-<NUM>) and perpendicular to said Y-axis;
at least a portion of the cross-section of said partition wall (<NUM>-<NUM>) in said reference plane shows a concave upward curve (44b-44f) while moving from the origin (<NUM>-<NUM>) towards positive values of said X-axis following said direction of rotation (D) of the rotor (<NUM>),
wherein said rotor (<NUM>) comprises at least one blade (BL) having a leading edge (Le), a trailing edge (Te) and a chord line (CL), characterized in that the distance (d1-d5) between said origin (<NUM>-<NUM>) and the circumference (C) determined by said trailing edge (Te) during rotation of said rotor (<NUM>) has a value higher than <NUM>,<NUM> times the length of said chord line (CL).