Background of the Invention There are well known the refrigerators of the type with only one front door, which is usually provided with inner shelves and which closes a usually parallelepipedic refrigerating cabinet, which is refrigerated, by natural convection, by an internal upper evaporator, which is usually of the plate type and has a lateral profile in the form of a"C"defined by upper and lower horizontal walls connected by a rear vertical wall, the upper and rear walls being slightly spaced from the adjacent upper and rear walls of the cabinet, so as to allow the circulation of air.

In these refrigerators operating by natural convection, usually for domestic use, the refrigeration of the food articles stored therein is mainly achieved by the cold air circulating inside the cabinet, said cold air acting as a"carrier"of thermal energy. However, the speed of the cold air circulating inside the cabinet is very low and this air circulation should be facilitated by the project of the internal components of the refrigerator, which components should minimize their interference in the free circulation of the convective currents.

According to the above observations, the shelves provided inside the cabinet of the type of

refrigerator considered herein are usually made of wire in the form of a grid, in order to make them "permeable"to the circulation of the refrigerating cold air. However, due to this constructive characteristic, the shelves of the cabinet are not very practical to accomodate certain types of food articles and containers. Containers with a narrow base have to be"equilibrated"on the grid shaped shelves, since they may tilt, allowing the products, which many times are liquid, to fall down to the lower shelves.

In order to minimize this deficiency, the user provides, on the shelves, basic plates or trays, which serve as a better support for carrying the food articles and containers. But this practice usually jeopardizes considerably the effective circulation of cold air inside the cabinet.

Disclosure of the Invention It is a general object of the present invention to provide a deflector for air currents of natural convection inside the cabinet of a refrigerator, which may guarantee, through a simple construction, an adequate and efficient circulation of the descending cold air currents and of the ascending hot air currents, even with the provision of non-perforated shelves inside the cabinet.

The deflector for air currents of natural deflection is applied to refrigerators comprising a cabinet provided with an upper wall, a rear wall, lateral walls and a bottom wall and a front door ; an evaporator with upper and rear walls spaced from the upper and rear walls of the cabinet; and a tray, for collecting defrost water, provided under the evaporator.

According to the invention, the deflector comprises a plate, which is provided parallely to and spaced from

the rear wall of the cabinet and occupying substantially the whole inner width thereof defined between its lateral walls, said plate vertically extending, from the level of the lowermost shelf, up to the level of the upper wall of the evaporator, in order to define, with the rear wall of the cabinet, a duct for the ascending hot air current, said plate maintaining a certain spacing in relation to the rear wall of the evaporator and to the rear edge of the tray and shelves, so as to define therewith a free passage for the descending cold air current.

The deflector defined above permits to separate the ascending hot air current, which is generated along the rear wall of the cabinet, from the descending cold air current, which is generated by the rear wall of the evaporator, so that said air currents of natural convection, with the same direction but in opposite senses, may develop in an efficient and ordered manner, even if the shelves of the cabinet are of the non-perforated type. This ordering of the descending cold air current allows the efficient distribution of the latter through the several levels of the non- perforated shelves of the cabinet, uniformly reaching the whole inside of the refrigerator.

Besides leading to the advantage mentioned above, the provision of the deflector of the present invention prevents the ascending and descending currents from colliding with each other under the tray for collecting defrost water and thus avoid part of the descending cold air current from deflecting forwardly against the door shelves, cooling them excessively.

Brief Description of the Drawings The invention will be described below, with reference to the attached drawing, in which: Figure 1 is a simplified vertical cross-sectional view

of a cabinet of a refrigerator with a single front door, constructed according to the present invention; and Figure 2 is a similar view to that of figure 1, but illustrating the cabinet provided with the deflector of the present invention.

Description of the Illustrated Embodiment As illustrated in the appended figures, the deflector of the present invention is applied to a refrigerator of the type comprising a cabinet 10 of refrigeration, usually parallelepipedic, with an upper wall 11, a rear wall 12, lateral walls 13 and a bottom wall 14, and which is closed at its front by a front door 20 provided with inner shelves 21. The cabinet is internally refrigerated by an evaporator 30, usually of the plate type with a lateral profile in the form of a"C"turned to the front door 20 and having an upper wall 31 and a rear wall 32 spaced from the upper wall 11 and rear wall 12, respectively, of the cabinet 10, and also a lower wall 33.

Under the lower wall 33 of the evaporator 30 is positioned a tray 40, for collecting the defrost water, which maintains a spacing in relation to the rear wall 12 of the cabinet 10, there defining a gap V for the passage of a descending cold air current, represented by the arrows F, which is originated in the rear upper region of the evaporator 30 and which is partly forwardly deflected, by a rear ascending hot air current, represented by the arrows Q, which is originated at the bottom of the cabinet 10 and which is partly downwardly directed through the median region of the shelves 15 in the form of a wired grid.

The part of the cold air current F, which is forwardly deflected by the hot air current Q, reaches the inner shelves 21 of the front door 20.

As illustrated in figure 2, in order to avoid the descending cold air current F from being directed against the ascending hot air current Q and thus deflected towards the inner shelves 21 of the front door 20, there is provided the deflector of the present invention, comprising a plate 50, which is usually flat, constructed in any adequate material and provided parallely to and spaced from the rear wall 12 of the cabinet 10.

The plate 50 is dimensioned so as to occupy, preferably, the whole internal width of the cabinet 10 defined between its lateral walls 13, maintaining with the rear wall 12 of the cabinet 10 a spacing of about 20mm and vertically extending, from the level of a lower shelf 15, usually the lowermost, up to the level of the upper wall 31 of the evaporator 30. With this constructive arrangement, the plate 50 defines with the rear wall 12 of the cabinet 10, which is usually hotter, a duct for the ascending hot air current Q, said duct operating as a kind of"chimney"for the hot air formed in the lower region of the cabinet 10 underneath a lower shelf, usually the lowermost shelf 15.

As illustrated, the plate 50 is provided so as to maintain a minimum spacing of about 30-35 mm in relation to the rear wall 32 of the evaporator 30 and to the rear edge of the tray 40, and a spacing of about 20 mm in relation to the rear edge of the shelves 15 of the cabinet 10. With this arrangement, the plate 50 defines, anteriorly, and with the rear wall 32 of the evaporator 30 and with the rear edge of the tray 40 and shelves 15, a free passage for the descending cold air current F which may be adequately maintained in its descending trajectory, uniformly reaching the whole inside of the cabinet 10, even in case the shelves 15 are constructed in a non- perforated material or blocked by plates, trays or other supporting objects or even by the construction of the products or articles.