WO2025057252A1

WO2025057252A1 - Heating device

Info

Publication number: WO2025057252A1
Application number: PCT/IT2024/050179
Authority: WO
Inventors: Maddalena RENIER; Paolo Gemionite; Marco STORTI
Original assignee: De Longhi Appliances SRL
Current assignee: De Longhi Appliances SRL
Priority date: 2023-09-12
Filing date: 2024-09-06
Publication date: 2025-03-20
Anticipated expiration: 2026-03-12
Also published as: IT202300018645A1

Abstract

Heating device (10) comprising a box-shaped containing body (11) formed by a plurality of walls (15) and provided with an air inlet aperture (12) and an air outlet aperture (13) which define a direction of travel (A) for an air flow (F), and heating members (19) with an elongated shape disposed inside said containing body (11) transversely with respect to said direction of travel (A) between two opposing first walls (15a, 15b) of said plurality of walls (15).

Description

“HEATING DEVICE”

FIELD OF THE INVENTION

The present invention concerns a heating device, preferably of the wall-mounted or portable type, which can find application, for example, in the field of household appliances for heating domestic or work spaces.

BACKGROUND OF THE INVENTION

Heating devices, such as electric radiators and electric convectors, are known, commonly used to heat spaces such as rooms, hallways or similar spaces, whether for home or work use.

These known heating devices normally comprise a box-shaped external body having a lower aperture and an upper aperture, and in which some electrical resistors are inserted which, when activated, heat the air inside the box-shaped body, triggering a natural convective air flow and introducing heated air into the space.

A disadvantage of known heating devices consists in the fact that, during steadystate operation, the upper portion of the external body heats up much more than the lower portion. Consequently, the upper portion can reach a temperature even higher than 100°C, while the lower portion has a temperature slightly higher than room temperature. This is due to the fact that the air passing inside the box-shaped body is progressively heated in its ascending motion from the lower aperture to the upper aperture.

This disadvantage makes known heating devices particularly dangerous and increases the risk of burns in the event that a user comes into contact with the upper part of the heating device’s box-shaped body.

A non-optimal distribution of heat on the external walls of the heating device’s body also decreases, or in any case makes inhomogeneous, the heat transmitted in the space by irradiation, consequently decreasing the comfort felt by the user.

The inhomogeneity of heat transmitted in the space creates a thermal stratification, whereby at floor level the temperature is much lower than the temperature at an intermediate height or at ceiling level. This is particularly felt in Asian countries, such as Japan for example, where traditionally many activities are carried out on or in proximity to the floor, so there is a need to heat rooms evenly, especially in the lower zones.

US 5197111 A describes a convection heating device suitable to be positioned adjacent to a wall, having an air inlet aperture made on a front wall and comprising a plurality of heating elements having a plurality of fins, positioned according to a stepped configuration or aligned with each other in a horizontal direction so that the heated air rising above each heating element causes the blown air rising above the heating element immediately behind to flow toward the outside of the outlet slots in the opposite direction to the wall, in order to prevent the formation of lines on the wall and damage to the coatings. The document NL 43409 C describes a convection heating device suitable to be positioned adjacent to a wall, having an inlet aperture and an outlet aperture for the air which are made on a front wall which, during use, is further away from the wall, and provided with heating members concentrated in correspondence with a lower part of the heating device. The document KR 101258199 Bl describes a convection electric boiler comprising a plurality of heat transfer chambers provided with electric heaters, which are separated and connected in sequence to allow for a gradual heat transfer, wherein the electric heaters are disposed in such a way as to rotate in the circumferential direction between an inlet and an outlet. These solutions do not allow to properly heat the zone in proximity to the floor, or in any case to the heating device’s rest plane.

There is therefore the need to perfect a heating device that can overcome at least one of the disadvantages of the state of the art.

To do this, it is necessary to solve the technical problem of decreasing the maximum temperature reached by the upper portion of the heating device’s body, in a steady-state condition, without compromising the heating efficiency.

One purpose of the present invention is to provide a heating device that allows to limit the maximum temperature to which its external body heats, to a temperature that is less dangerous for the user. Another purpose of the present invention is to provide a heating device that allows to improve the temperature distribution on the walls of its external body, and therefore improve the uniformity with which the surrounding space is heated.

Another purpose of the present invention is to provide a heating device that allows to provide radiant heat to the surrounding space, even in correspondence with a lower portion of the heating device.

Another purpose of the present invention is to provide a heating device able to optimize both the convective heat exchange and also the radiative heat exchange, in order to speed up and make uniform the heating of the surrounding space.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the above purposes and to resolve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a heating device according to the present invention for heating home and work spaces comprises a box-shaped containing body formed by a plurality of lateral walls that delimit a compartment, the containing body being provided with an air inlet aperture on the bottom and an air outlet aperture on the top, which define a direction of travel for an air flow, inside which there are heating members separated from and independent of each other, which have an elongated shape and are disposed transversely with respect to the direction of travel between two opposing first main walls of the plurality of walls.

In accordance with one aspect of the present invention, the heating members are positioned in the direction of travel and distributed at different heights, at a distance which progressively increases from at least one of the first walls starting from the air inlet aperture.

Doing so achieves a heating device that allows to improve the temperature distribution on the external lateral walls of its containing body, increasing the temperature of the lower zone and therefore improving the uniformity with which the surrounding space is heated, particularly, but not only, in the zones close to the floor.

According to some embodiments, the heating members are positioned substantially parallel to each other and to the lateral walls. In accordance with one aspect of the invention, at least a first heating member is disposed in a lower half of the containing body, preferably in proximity to the bottom of the containing body.

In accordance with one aspect of the invention, at least a second heating member is disposed in an upper half of the containing body, separate and spaced apart from the first heating member, preferably in proximity to the top.

In accordance with one aspect of the invention, the heating members are positioned at a distance which progressively increases from both of the first main walls starting from the air inlet aperture toward the air outlet aperture. In accordance with another aspect of the present invention, the heating device comprises heat distribution means formed by at least one shielding element disposed facing between the first walls and the heating members.

In accordance with another aspect of the present invention, the at least one shielding element is provided with a solid part on which there are a plurality of apertures.

According to another aspect of the present invention, the at least one shielding element can also be provided with at least one stiffening portion.

In accordance with another aspect of the present invention, the ratio between a surface of the solid part and a total surface of an ideal shielding element of equal external sizes (length, width) without apertures can be comprised between about 0.1 and about 0.45, preferably between about 0.15 and about 0.35.

In accordance with another aspect of the present invention, the ratio between a volume of the solid part and a total volume of an ideal shielding element of equal external sizes (length, width and thickness) without apertures can be comprised between about 0.05 and about 0.3, preferably between about 0.1 and about 0.25.

In accordance with another aspect of the present invention, the heating members are preferably disposed according to a configuration that is symmetrical with respect to a central plane intermediate between the first walls, wherein the symmetrical configuration has an isosceles triangle or trapezium like pattern. In accordance with another aspect of the present invention, each heating member has a shape that is preferably tubular U-shaped, with two elongated arms attached to at least a second wall of the plurality of walls, wherein the heating members are aligned and overlapping vertically. In particular, each heating member is preferably disposed with its arms aligned and overlapping vertically.

In accordance with another aspect of the present invention, the heating members are divided into at least two distinct groups, wherein each group comprises at least one heating member and is disposed in a certain position along a height of the containing body.

In accordance with another aspect of the present invention, at least one group is positioned in correspondence with a lower half of the containing body, in particular in proximity to the bottom, and at least one group is positioned in correspondence with an upper half, in particular in proximity to the top. According to some embodiments, there are at least three groups of heating members, two of which disposed in correspondence with the lower half of the containing body, preferably one in proximity to the bottom of the containing body and one in correspondence with a central zone.

According to some embodiments, the at least one shielding element is disposed in correspondence with a second group of the groups, which is intermediate between the air inlet aperture and the air outlet aperture.

According to one embodiment of the present invention, the heating members are divided into three groups and the shielding element is disposed in correspondence with the second group, which is intermediate between a first and a second group of the groups.

According to one aspect of the invention, both arms of each heating member of one of the groups are located above or respectively below the respective height of both arms of each heating member of the preceding or subsequent group.

According to another aspect of the invention, a vertical distance, or gap, between two heating members of the groups increases along the height of the heating device in the direction of travel between the air inlet aperture and the air outlet aperture.

In accordance with some embodiments of the present invention, the heating device can comprise distinct and independent power supply means to autonomously energize each of the groups of heating members.

In accordance with other embodiments of the present invention, the heating device can comprise distinct and independent power supply means to simultaneously energize at least one of the heating members of the second group and at least one of the heating members of a first group, the latter being disposed closer to the air inlet aperture than the other groups. According to one embodiment of the present invention, the heating members of the first and second group powered simultaneously are preferably disposed “intersecting”, that is, respectively closer to one and the other of the first two walls of the heating device’s containing body.

Some embodiments of the present invention concern a method of operation of a heating device in which an air flow passes through a box-shaped containing body, formed by a plurality of walls, in a direction of travel from an air inlet aperture to an air outlet aperture lapping heating members which have an elongated shape and are disposed inside the containing body transversely with respect to the direction of travel between two opposing first walls of the plurality of walls, the heating members being positioned in the direction of travel at a distance of installation which progressively increases from at least one of the first walls starting from the air inlet aperture.

DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein: - fig. 1 is a three-dimensional view of a heating device according to the present invention, in which a part of the containing body has been sectioned to make the internal part visible;

- fig. 2 is a section view of the heating device of fig. 1 ;

- figs. 3a, 3b schematically show the heating members of fig. 2 identified with letters “A”, “B” and “C” to clarify the diversified driving modes thereof; and

- fig. 4 is a three-dimensional view showing a possible embodiment of the shielding element visible in figs. 1 and 2.

We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications. DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

With reference to figs. 1 and 2, a heating device 10 according to the present invention is essentially designed to generate heating of home or work spaces, both by irradiation and also by convection. More in detail, the heating device 10 can be an electric radiator or an electric convector, or a device having characteristics that combine both those of an electric radiator as well as those of an electric convector. The heating device 10 can therefore be a convector radiator device.

The heating device 10 comprises a containing body 11 , preferably box-shaped, having an air inlet aperture 12 and an air outlet aperture 13.

The air inlet aperture 12 is positioned at a lower height than the air outlet aperture 13 and is preferably opposite, facing and aligned with the former, with respect to a vertical direction.

In other words, the air inlet aperture 12 is made in correspondence with a bottom of the containing body 11 and the air outlet aperture 13 is made on its top.

The containing body 11 can be provided with rest elements - such as feet, wheels, supports in general - disposed for example in proximity to the air inlet aperture 12 to position the heating device 10 on the floor of a room.

The apertures 12 and 13 are communicating fluidically and their reciprocal positioning defines a mainly linear direction of travel A for an air flow F directed from the air inlet aperture 12 to the air outlet aperture 13.

Filtering elements such as grids, filters, or other similar components can be associated with the apertures 12, 13, in a manner known per se.

The containing body 11 can, for example, comprise four walls 15, preferably made of metal, for example of aluminum or steel, connected to each other and defining a box-shaped body with a rectangular tubular section, open in correspondence with the apertures 12, 13.

Since the containing body 11 is essentially “empty”, there are no strict requirements to ensure its structural integrity. Assembly is easy, there are few components and the walls 15 can be thin and light. The heating device 10 heats up very quickly, giving an immediate benefit to the user who also benefits from its reduced weight, since they can position it at will in the room.

The containing body 11 can comprise two facing first or main walls 15a, 15b, with a greater extension, and two opposing second or head walls 15c, 15d, with a smaller extension, substantially perpendicular to the two main walls 15a, 15b. Each head wall 15c, 15d is connected to both main walls 15a, 15b.

The height H of the walls 15 is substantially the same and can be essentially equal to the distance between the air inlet aperture 12 and the air outlet aperture 13.

The distance between the main walls 15a, 15b defines the width W of the heating device 10, while the distance between the head walls 15c, 15d defines the depth T of the heating device 10.

The two main walls 15a, 15b can be parallel to each other or slightly inclined to each other. For example, the two main walls 15a, 15b can be converging toward the air outlet aperture 13 (fig. 2) so as to induce a venturi effect for the air flow F passing inside the containing body 11. In this case, at least the width W of the containing body 11 can vary linearly along the height H.

According to some embodiments, in addition or alternatively to the main walls 15a, 15b, the head walls 15c, 15d can also converge toward the air outlet aperture 13. However, a person of skill in the art will easily understand that the number of walls 15 of the containing body 11 can also be different from four, and that their conformation can also differ from what described here. Consequently, even the apertures 12, 13, which have a substantially rectangular section in the embodiments shown, in other possible embodiments can also have different shapes, for example circular or elliptical, or each of them can be defined by a plurality of slits positioned side by side.

Each wall 15 has an internal surface 16 facing the inside of the containing body 11 and an external surface 17 facing the outside of the containing body 11. By way of example, the external surface 17 of at least one wall 15 can face the space, or the room, to be heated.

The heating device 10 also comprises a plurality of heating members 19 disposed at least partly, preferably completely, inside the containing body 11.

Each heating member 19 is configured to generate heat and heat the air that laps it by conduction, and is connected to electric power supply means (not shown).

According to some embodiments, each heating member 19 can comprise at least one electrical resistance. The electrical resistance is suitable to produce heat by exploiting the Joule effect. Preferably, the heating members 19 are located directly in contact with the air travelling inside the containing body 11.

The electric power supply means comprise a plurality of electronic components. For example, the electric power supply means can comprise at least one element - preferably two, three or more - known in the field by the English acronym “triac” (triode for alternating current) which serves to control the alternating current loads that energize the heating members 19.

We must clarify that the heating device 10 of the present invention is preferably of the static type, that is, without ventilation members. In fact, during use, the heat produced by the heating members 19 triggers a natural convection of the air present in the space to be heated, so as to create an air flow F entering through the air inlet aperture 12 and exiting from the air outlet aperture 13.

According to alternative embodiments not shown, the heating device 10 can comprise at least one ventilation member to generate a forced air flow. In this case, the operation of the heating device 10 can be dual: simple natural convection, with ventilation member deactivated, or mixed convection, natural and forced, with ventilation member activated.

The heating members 19 preferably have an elongated shape and are positioned transversely with respect to the direction of travel A. By way of example, if the direction of travel A is vertical, the heating members 19 are positioned horizontally, optionally parallel to the main walls 15a, 15b.

According to possible variants, the heating members 19 can be disposed transversely to the direction of travel A, but slightly inclined upward, that is, toward the air outlet aperture 13, or downward, that is, toward the air inlet aperture 12. The heating members 19 are preferably connected to the containing body 11 in correspondence with one of their ends, remaining predominantly exposed to the air flow F that laps them. In this way, the air flow is heated immediately, and the higher the temperature of the heating members 19, the faster and more effective the temperature increase in the space, since the heat transfer is enhanced.

According to the present invention, the heating members 19 are positioned at a certain distance of installation D from at least one of the main walls 15a, 15b, this distance D being progressively increasing starting from the air inlet aperture 12 toward the air outlet aperture 13 in the direction of travel A. In other words, the distance of installation D of the heating members 19 from the main walls 15a, 15b they face increases with the height H of the heating device 10.

This positioning of the heating members 19 allows to concentrate most of the overall heat generated in proximity to the air inlet aperture 12 and therefore to the lower portion of the containing body 11 , increasing the temperature homogeneity inside the containing body 11 and also improving the diffusion of radiative heat toward the space at floor level.

According to the embodiment shown by way of example in fig. 1 , each heating member 19 can preferably have a tubular “U” shape with two elongated arms 19a attached to one of the head walls 15c, 15d. Advantageously, although not strictly necessary, the heating members 19 are all connected to the same head wall 15c.

The extension of the tubular members 19 can essentially be slightly smaller than the depth T of the containing body 11. The curved part of the “U” is located in proximity to the head wall 15d opposing the connection wall.

The heating members 19 are disposed inside the containing body 11 preferably with their arms 19a aligned and overlapping vertically, that is, disposed on a respective vertical plane parallel to a central plane S of the containing body 11.

The heating members 19 are advantageously divided into at least two distinct groups Gl, G2, G3, wherein each group comprises at least one heating member 19 and is disposed in a certain position along the height H of the heating device 10.

The groups Gl, G2, G3 can be formed by a same or different number of heating members 19. The number of heating members 19 of each group can be one, two, three or more. In the event a group has a number of heating members 19 higher than one, the heating members 19 are preferably oriented parallel to each other.

According to some embodiments, both arms 19a of each heating member 19 of one of the groups Gl, G2, G3 are located above, or respectively below, the respective height H of both arms 19a of each heating member 19 of the group Gl, G2, G3 that precedes or follows in the direction of travel A. In other words, the heating members 19 of two distinct groups Gl, G2, G3 do not overlap, even partly, in a horizontal direction.

The number of heating members 19 can advantageously decrease, or at most remain unchanged, along the height H of the heating device 10 in the direction of the air outlet aperture 13.

The heating members 19 can be disposed according to a configuration that is symmetrical with respect to the central plane S, which is essentially vertical, fig. 2. The central plane S can be intermediate between the two main walls 15a, 15b or orthogonal to the air inlet and outlet apertures 12, 13. According to possible embodiments, the symmetrical configuration can have an isosceles triangle or trapezium like pattern.

According to some embodiments, there are two groups Gl, G3 of heating members 19, one group Gl positioned in correspondence with a lower half of the containing body 11 , in particular in proximity to the bottom of the containing body 11, and one group G3 positioned in correspondence with an upper half, in particular in proximity to the top of the containing body 11.

According to some embodiments, there are three groups Gl, G2, G3 of heating members 19, wherein two groups Gl, G2 are disposed in correspondence with the lower half of the containing body 11 , preferably one in proximity to the bottom and one in correspondence with a central zone, and one group G3 is positioned in correspondence with the upper half.

According to some embodiments, a first group Gl is disposed in proximity to the air inlet aperture 12 and comprises two heating members 19, a third group G3 is disposed in proximity to the air outlet aperture 13 and comprises a single heating member 19, while a second group G2 is intermediate between the first group Gl and the third group G3 and it also comprises two heating members 19. In this case, the number of heating members 19 is equal to five in total.

According to some embodiments, the heating members 19 of the first group Gl can be positioned respectively at a first distance of installation DI’, DI”, for example equal to about ’A and about A of the distance between the two main walls

15a, 15b, measured starting from the same main wall 15a, 15b. The heating members 19 of the second group G2 can be positioned respectively at a second distance of installation D2’, D2” greater than the first distance of installation DI ’, DI ”, for example equal to about ²/₅ and about ³/s of the distance comprised between the two main walls 15a, 15b, measured starting from the same main wall 15a, 15b. The single heating member 19 of the third group G3 can be positioned at a third distance of installation D3 greater than the second distance of installation D2, D2”, for example equal to about 14 the distance between the two main walls 15a, 15b.

According to possible embodiments, the vertical distance, or gap, between the groups G1-G3 can increase along the height H of the heating device 10. Therefore, the proximity of the first group G1 to the second group G2 is greater than proximity of the second group G2 to the third group G3.

According to possible embodiments, the heating members 19 can preferably be made of a non-magnetic metal material, for example of an austenitic non-magnetic stainless steel, and their surface can possibly be covered with a coating layer capable of increasing the emissivity of the material that the heating members 19 are made of, and consequently increasing the heat transmitted to the surrounding space.

The heating device 10 also comprises heat distribution means 20 configured to distribute the radiative heat generated by the heating members 19 on the walls 15, in a differentiated manner in the direction of travel A, so as to make at least the temperature of the main walls 15a, 15b uniform.

The heat distribution means 20 are disposed in an intermediate position between the air inlet aperture 12 and the air outlet aperture 13. Preferably, the shielding provided by the distribution means 20 is greater in the central portion of the containing body 11 and is smaller in the lower and upper portion thereof.

Advantageously, during steady-state operation of the heating device 10, excessive heating of the upper portion of the containing body 11 is avoided and, at the same time, heating of the lower portion of the containing body 11 is improved, without compromising the performance of the heating device 10. In fact, in this way, the heating device 10 can provide adequate comfort to the user by optimally heating the zone near the floor and at the same time preventing the temperature of the upper portion of the containing body 11 during steady-state operation from being excessive, for example, exceeding 80°C, reducing the risk of bums for the user.

The Applicant has experimented, starting from a room temperature of 25°C and powering the heating device 10 with a power of 1500W, that the surface temperature of the main wall 15a, 15b is essentially uniform. In particular, the following has been tested:

- the difference between the maximum temperature (~86°C) and the minimum temperature (~47°C) of the main wall 15a, 15b is less than 40°C;

- more than 90% of the surface is above 60°C and below 86°C;

- more than 85% of the surface is above 60°C and below 80°C;

- about 60% of the surface is above the surface’s average temperature (~71°C).

The heat distribution means 20 comprise at least one shielding element 21, 22 substantially parallel, or sub-parallel, with respect to the main walls 15a, 15b.

The shielding element 21, 22 can have a predominantly flat conformation. The shielding element 21 , 22 can for example have a rectangular shape with a certain length, width and thickness.

According to some embodiments, the at least one shielding element 21, 22 has an extension in depth T substantially corresponding to an extension of the main walls 15a, 15b.

In the example of fig. 2, the heat distribution means 20 comprise at least a first shielding element 21 interposed between the heating members 19 and a first main wall 15a (left wall), and at least a second shielding element 22 interposed between the heating members 19 and a second main wall 15b (right wall), which faces the first main wall 15 a.

The shielding elements 21, 22 are advantageously disposed in correspondence with the second group G2 of heating members 19, for example in an intermediate position between the nearest main wall 15a, 15b and the nearest heating member 19.

The shielding elements 21, 22 can be attached to the two head walls 15c, 15d and have a prevalent extension parallel to the main walls 15a, 15b.

According to some embodiments, each shielding element 21, 22 can comprise a solid part 26, for example a mesh 23, preferably made of metal material, provided with apertures 25. The mesh 23 can be formed by the intersection or overlap of a plurality of wires which can for example have a circular, square, or other, section.

Depending on the shape of the apertures 25, the wires can be woven m orthogonal directions, according to a matrix-like configuration, or in other preferential directions.

According to possible embodiments, each shielding element 21, 22 can essentially comprise a plate, preferably made of metal, defining the solid part, having a plurality of apertures with a shape and position such as to vary the shielding provided in the direction of travel A.

According to some embodiments, the apertures 25 can be distributed uniformly on the surface of the shielding element 21, 22. However, solutions in which the apertures 25 can be present, or made, according to an inhomogeneous pattern are not excluded, for example according to a more or less intricate pattern in some specific zones of the shielding element 21, 22.

The apertures 25 can all be the same or have different shapes and/or sizes.

The apertures 25 can have a polygonal shape, for example square, rectangular, rhomboidal, circular, ellipsoidal. In one possible example embodiment, the apertures 25 can have a square shape and a size of 6 mm x 6 mm. In another possible example embodiment, the apertures 25 can have a square shape and a size of 5 mm x 5 mm. In another possible example embodiment, the apertures 25 can have a rhomboidal shape and a size of 3 mm x 3 mm.

According to some embodiments, the ratio between a surface of the solid part 26 and a total surface of an ideal shielding element of equal external sizes (length, width) without apertures can be comprised between about 0.1 and about 0.45, preferably between about 0.15 and about 0.35.

According to some embodiments, the ratio between a volume of the solid part 26 and a total volume of an ideal shielding element of equal external sizes (length, width and thickness) without apertures can be comprised between about 0.05 and about 0.3, preferably between about 0.1 and about 0.25.

According to some embodiments, the shielding elements 21, 22 can be provided with stiffening portions 24 to preserve their geometry even in case of high thermal gradients.

The stiffening portion 24 can be a locally deformed zone of the shielding element 21, 22. In fig. 4, the stiffening portions 24 are obtained by plastic deformation of the mesh 23. Alternatively, the stiffening portion 24 can be obtained by applying a ribbed component to the shielding element 21, 22. According to some embodiments of the present invention, the heating members 19 are electrically powered in groups, in such a way as to manage the heating device 10 according to a first operating mode, at nominal power, and also according to at least a second operating mode, at a power lower than the nominal power. In the first operating mode all the heating members 19 are switched on, while in the second operating mode some heating members 19 are switched off to limit energy consumption, or simply because the heating power required is less than the nominal or maximum one.

In fig. 3a, the groups G1-G3 of heating members 19 are independently powered according to three operating modes. The simultaneous drive of the pair C-C of heating members 19 allows for a heat distribution that promotes the radiative heating of the zones close to the floor.

In fig. 3b, the heating member 19 of the third group G3 is independently powered while the heating members 19 of the other two groups Gl, G2 are cross powered. For example, it is possible to activate the pairs CC and BB of heating members 19 simultaneously. This solution can guarantee a particularly uniform temperature of the walls 15 of the containing body 11.

The operation of the heating device 10, which corresponds to the method according to the present invention, provides that the air flow F passes through the containing body 11 in the direction of travel A from the air inlet aperture 12 to the air outlet aperture 13, lapping the heating members 19 that are disposed inside the containing body 11, the heating members 19 being positioned in the direction of travel A at a distance of installation D which progressively increases from at least one of the first walls 15a, 15b starting from the air inlet aperture 12.

It is clear that modifications and/or additions of parts may be made to the heating device 10 as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims.

Although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of heating device, having the characteristics as set forth in the claims all coming within their field of protection.

In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

1. Heating device (10) comprising a box-shaped containing body (11) formed by a plurality of lateral walls (15) that delimit a compartment, the containing body

(11) being provided with an air inlet aperture (12) on the bottom and an air outlet aperture (13) on the top which define a direction of travel (A) for an air flow (F), wherein inside said compartment there are heating members (19), separated from and independent of each other, which have an elongated shape and are disposed transversely with respect to said direction of travel (A) between two respectively opposing first main walls (15a, 15b) of said plurality of walls (15), characterized in that said heating members (19) are positioned at different heights in said direction of travel (A) and at a distance (D) which progressively increases from at least one of said first main walls (15a, 15b) starting from said air inlet aperture

(12).

2. Heating device (10) as in claim 1, characterized in that said heating members (19) are positioned at a distance (D) which progressively increases from both said first main walls (15a, 15b) starting from said air inlet aperture (12) toward said air outlet aperture (13).

3. Heating device (10) as in claim 1 or 2, characterized in that it comprises heat distribution means (20) formed by at least one shielding element (21, 22) disposed facing between at least one of said first walls (15a, 15b) and at least one of said heating members (19).

4. Heating device (10) as in claim 3, characterized in that said at least one shielding element (21, 22) is provided with a solid part (26) on which there are a plurality of apertures (25) and with at least one stiffening portion (24). 5. Heating device (10) as in claim 3 or 4, characterized in that said at least one shielding element (21, 22) has an extension in depth (T) substantially corresponding to an extension of said first main walls (15a, 15b).

6. Heating device (10) as in claim 4 or 5, characterized in that the ratio between a surface of the solid part (26) and a total surface of an ideal shielding element of equal external sizes without apertures can be comprised between 0.1 and 0.45, preferably between 0.15 and 0.35, and/or the ratio between a volume of the solid part (26) and a total volume of said ideal shielding element is comprised between 0.05 and 0.3, preferably between 0.1 and 0.25.

7. Heating device (10) as in any claim hereinbefore, characterized in that said heating members (19) are disposed according to a symmetrical configuration, isosceles triangle or trapezium like, with respect to a central plane (S) intermediate between said first main walls (15a, 15b).

8. Heating device (10) as in any claim hereinbefore, characterized in that each heating member (19) has a tubular “U” shape with two elongated arms (19a) attached to at least a second wall (15c, 15d) of said plurality of walls (15), and in that the respective arms (19a) of each of said heating members (19) are aligned and overlapping vertically.

9. Heating device (10) as in any claim hereinbefore, characterized in that at least a first heating member (19) is disposed in a lower half of the containing body (11) in proximity to the bottom of the containing body (11) and at least a second heating member (19) is disposed in an upper half of the containing body, separate and spaced apart from the first heating member (19), preferably in proximity to the top.

10. Heating device (10) as in any claim hereinbefore, characterized in that said heating members (19) are divided into three distinct groups (Gl, G2, G3) separated from each other, wherein each of said groups (Gl, G2, G3) comprises at least one heating member (19) and is disposed in a certain position along a height (H) of said containing body (11), different from the position of each of the other groups (G1, G2, G3).

11. Heating device (10) as in claims 3 and 10, characterized in that said at least one shielding element (21, 22) is disposed in correspondence with a second group (G2) which is intermediate between a first and a second group (Gl, G3) of said groups (Gl, G2, G3).

12. Heating device (10) as in any claim hereinbefore, characterized in that a vertical distance, or gap, between said heating members (19) increases along the height (H) of said heating device (10) in the direction of travel (A).

13. Heating device (10) as in any claim from 10 to 12, characterized in that it comprises distinct and independent power supply means to autonomously energize each of said groups (Gl, G2, G3).

14. Heating device (10) as in any claim from 9 to 12, characterized in that it comprises distinct and independent power supply means to simultaneously energize at least one of the heating members (19) of said second group (G2) and at least one of the heating members (19) of a first group (Gl) which is disposed closer to said air inlet aperture (12) than the other groups (G2, G3).

15. Heating device (10) as in any claim hereinbefore, characterized in that at least said first main walls (15a, 15b) are converging from said air inlet aperture (12) toward said air outlet aperture (13).

16. Method of operation of a heating device (10) in which an air flow (F) passes through a box-shaped containing body (11), formed by a plurality of walls (15), in a direction of travel (A) from an air inlet aperture (12) located in correspondence with a bottom of said containing body (11) to an air outlet aperture (13) located in correspondence with a top of said containing body (11), lapping heating members

(19) which have an elongated shape and are disposed inside said containing body

(11) transversely with respect to said direction of travel (A) between two respectively opposing first main walls (15a, 15b) of said plurality of walls (15), said heating members (19) being positioned at different heights in said direction of travel (A) and at a distance of installation (D) which progressively increases from at least one of said first main walls (15a, 15b) starting from said air inlet aperture