WO2019220411A1

WO2019220411A1 - Heating radiator element

Info

Publication number: WO2019220411A1
Application number: PCT/IB2019/054103
Authority: WO
Inventors: Orlando NIBOLI
Original assignee: Fondital S.P.A. A Socio Unico
Priority date: 2018-05-17
Filing date: 2019-05-17
Publication date: 2019-11-21
Also published as: EA202092702A1; LT3794300T; GEP20227423B; HRP20240152T1; IT201800005477A1; EP3794300B1; RS65169B1; EP3794300A1; SI3794300T1

Abstract

A heating radiator element (1) comprises a body (2) extending substantially along a longitudinal axis (A) and at least a tern of adjacent fins (11), arranged side by side and having at least respective longitudinal main sections (21) substantially parallel to the axis (A) and substantially vertical in use, for example substantially straight; the ratio (R) between the axial length (LI) of the longitudinal section (21) of a first fin (11.1) of the tern and the sum of the axial lengths (L2, L3) of the longitudinal sections (21) of a second and third fins (11.2, 11.3) of the tern, arranged on opposite sides of the first fin (11.1), being lower than or equal to 0.40.

Description

HEATING RADIATOR ELEMENT

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no. 102018000005477 filed on 17/05/2018, the entire disclosure of which is incorporated herein by reference .

TECHNICAL FIELD

The present invention relates to a heating radiator element, in particular for heating buildings.

BACKGROUND ART

It is known that common heating systems widely use radiator elements constituting the elements designed to transfer heat, mainly by convection, to the environment to be heated. A radiator element can be used alone or combined with other similar elements to form batteries of radiator elements .

There are various types of radiator elements.

For example, fluid circulation radiator elements are widely used, e.g. of the column type, plate type, etc., having a hollow body inside which a heating fluid circulates.

In electrical heating systems of any kind (fluid circulation, dry circulation, etc.), the radiator elements usually contain a high specific heat material heated by a resistor with an electric current. It is also common to provide the radiator elements with radiant plates and fins in order to increase the heat exchange surface with the environment in which they operate .

It is common, for example, a radiator element having an essentially tubular body, provided with an inner water chamber and hydraulic connections arranged at the opposite ends of the element. Two opposite partitions, respectively supporting a front plate and a back plate, extend along a middle plane of the element from the wall of the water chamber; a plurality of heat exchange fins project from opposite sides of the body and/or of the partitions.

In particular, it is known to arrange at least some of the fins on the water chamber (namely, it is known to have fins starting directly from the side wall that delimits the water chamber) so that these fins operate at a higher temperature .

For this kind of radiator elements, as well as for radiator elements of different types, e.g. with a plate configuration, and otherwise powered (for example electric) , it is also generally known increasing the performance of the radiator element by increasing the surface of the fins (and therefore the number and/or size of the fins) .

Although radiator elements having variously shaped and distributed plates and fins are known, the efficiency of known radiators still seems to have room for improvement.

In particular, it would be desirable to provide a radiator element with high efficiency, for example in terms of specific output or power per unit of weight (ratio between the thermal power emitted by the radiator element and transferred to the environment, measured according to specific regulations, for example EN 442, and the weight of the element, which is the fundamental parameter that directly affects production costs) .

DISCLOSURE OF INVENTION

It is therefore an object of the present invention to provide a particularly efficient heating radiator element which has high heat performances, superior to those of a traditional radiator element of comparable size, being at the same time simple and relatively inexpensive to manufacture .

The present invention therefore relates to a radiator element as essentially defined in the appended claim 1 and, in its additional characters, in the dependent claims.

A radiator element according to the invention has an efficiency higher than other known solutions of comparable size. In fact, the particular configuration of the radiant fins allows obtaining flow conditions that ensure a highly efficient heat exchange. The element of the invention is also achievable in a relatively simple and inexpensive way, and is even suitable to be manufactured, for example (but not only) , in die-cast aluminium, thus being particularly convenient to be produced .

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will appear clear from the following description of a non-limiting embodiment thereof, with reference to the figures of the annexed drawings, in which:

- Figure 1 is a schematic perspective view of a radiator element according to a first embodiment of the invention;

- Figure 2 is a side elevation view of the radiator element of Figure 1;

Figures 3A-3C are respective side elevation views of further embodiments of the invention;

Figures 4A-4B are respective side elevation views of further embodiments of the invention;

Figures 5A-5C are respective side elevation views of further embodiments of the invention;

- Figure 5D schematically shows how terns of adjacent fins are defined according to the invention, with reference to the embodiment of Figure 5A;

Figures 6A-6C are respective side elevation views of further embodiments of the invention; - Figures 7 and 8 are respectively a schematic perspective view and a front view of a radiator element according to a further embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figures 1 and 2, a radiator element 1 for heating buildings has a body 2, for example made of metallic material, in particular aluminium, and for example (but not necessarily) made of die-cast aluminium (i.e. made by aluminium die casting) .

The body 2 is a hollow body comprising a main portion 3 (substantially tubular in the non-limiting example of Figures 1-2) extending along a longitudinal axis A that, with reference to the normal position of use of the element 1, is substantially vertical; and transverse connecting sleeves 4 for the connection to other radiator elements and/or to a hydraulic circuit, arranged at respective axial ends 5, 6 of the main portion 3.

The main portion 3 is closed at the ends 5, 6 and has a side wall 7 extending around the axis A.

The upper end 5, in use (namely with reference to the normal position of use of the element 1), is preferably provided with a deflector 8 substantially transverse to the axis A and optionally curved towards the axis A, and with front flow openings 9 (namely oriented towards the environment to be heated, always with reference to the normal position of use of the element 1) .

The element 1 is provided with an inner chamber 10 (so- called water chamber) for the passage of water, which extends in particular inside the main portion 3, is delimited by the side wall 7 and communicates with respective inner ducts of the sleeves 4.

The element 1 then comprises a plurality of heat exchange fins 11.

In particular, the element 1 comprises: a pair of partitions 12, which project diametrically opposite from the side wall 7 parallel to the axis A and along a longitudinal middle line P of the element 1; and two groups of fins 11 arranged on respective surfaces 13 of the body 2, which project from the side wall 7 and/or from the partitions 12 substantially perpendicular to the partitions 12 and parallel to the axis A.

In this case, the surfaces 13 constitute respective sides of the element 1 and are defined by respective surface portions of the side wall 7 of the main portion 3 and by respective faces of the partitions 12.

The two groups of fins 11 arranged on the surfaces 13 are preferably symmetrical and opposite, so that the fins 11 arranged on the two surfaces 13 have the same and symmetrical structure and arrangement. However, it is clear that the two surfaces 13 can also have fins 11 different in shape, size and/or arrangement.

A group of fins 11 carried by a surface 13 (i.e. by one side of the element 1) is described below.

The surface 13 (in the example of Figures 1-2, each surface 13) has a plurality of fins 11.

The fins 11 are in particular substantially parallel to each other and substantially perpendicular to the middle line P.

The fins 11 can have different shapes and sizes.

In general, each fin 11 comprises at least one main longitudinal section 21, which is substantially parallel to the axis A and substantially vertical in use, for example substantially straight.

The section 21 can be continuous, i.e. with no cuts or interruptions (like the front end fin and the intermediate fins in the example of Figures 1-2), or interrupted, having one or more substantially transverse (or anyway oriented) cuts that separate portions of mutually longitudinally aligned fins (such as e.g. the rear end fin in the example of Figures 1-2) . In other words, the section 21 can be defined by a row of mutually aligned fin portions parallel to the axis A.

For example, the fins 11 and in particular the respective sections 21 are of a generically quadrilateral shape, optionally with curved edges and/or rounded corners. The section 21 of each fin 11 consists of a flat and thin lamina (or a series of laminae, if the section 21 is formed by a row of aligned fin portions) and has two opposite main faces 14, for example (but not necessarily) substantially flat and parallel, a root edge 15a joined to the body 2, an apical edge 15b having a free end, opposite the root edge 15a and for example substantially parallel to the root edge 15a, and a pair of side edges 16 joining the root edge 15a to the apical edge 15b. It is however clear that the fin 11 and its section 21 may have a different shape from the one described herein and shown merely by way of example.

The fins 11 (or some of them) may optionally include curved or inclined auxiliary sections with respect to the respective sections 21. In the embodiment of Figures 1-2, the sections 21 of the fins 11 coincide with the respective fins 11, and some additional curved fins are provided in particular in the upper front area of the element 1, spaced away from the fins 11.

In the non-limiting example of Figures 1-2, the fins 11 comprise: a pair of end fins 11a, arranged at respective free ends of the partitions 12 and defining, with the respective symmetrical fins 11a arranged on the opposite surface 13, a front plate and a rear plate of the element 1; and further fins lib, 11c having at least two respectively different lengths and being arranged between the end fins 11a on the side wall 7 (thus extending directly from the chamber 10) and/or on the partition 12. Here and in the following, length of a fin 11 or of a portion thereof 21 means the apical axial length, namely the length measured parallel to the axis A and along the apical edge 15b, opposite the root edge 15a joined to the body 2, of the fin 11 or of the section 21.

In the shown non-limiting example, the element 1 comprises (on the surface 13) a shorter fin lib arranged between two longer fins 11c (namely shorter and longer if compared to one another) and having, in this case, the same length. It is clear that there may be several fins lib, 11c as well as that the fins lib, 11c may have different lengths.

According to the invention, the surface 13 has at least one tern of adjacent fins 11, arranged side by side, extending substantially parallel to the axis A and having at least respective sections 21 substantially parallel to the axis A and substantially vertical in use.

The tern of adjacent fins 11 is formed by a first fin 11.1 arranged between a second and a third fins 11.2, 11.3 that are arranged on opposite sides of the first fin 11.1, are directly facing the first fin 11.1 and have in particular respective faces 14 oriented towards the first fin 11.1, namely facing respective faces 14 of the first fin 11.1. The tern of fins 11 in question (according to the invention) may be any tern of adjacent fins 11, not necessarily those indicated here by way of example (fins 11.1, 11.2, 11.3) .

In the example of Figures 1-2, the tern of adjacent fins 11 is formed in particular by a shorter fin lib (first fin 11.1) arranged between two longer fins 11c (second and third fins 11.2, 11.3) . However, the tern of adjacent fins

11 in question may be formed by other fins 11 otherwise arranged on the chamber 10 and/or on the partition 12, with the exception of the end fins 11a.

Each fin 11 of the tern (if, as in the example shown in

Figures 1-2, the fin 11 is substantially straight and parallel to the axis A), or each respective section 21 (if the corresponding fin 11 includes curved or inclined sections with respect to the axis A) has a certain length. This length is meant precisely, as already defined, as the apical axial length, measured parallel to the axis A and along the apical edge 15b, opposite the root edge 15a joined to the body 2, of the fin 11 or of the section 21. The sections 21 of the fins 11 of the tern are entirely arranged in a region of the body 2 comprised axially (i.e. along the axis A) between a pair of axially opposite sleeves 4 (arranged at respective axial ends 5, 6 axially opposite along the axis A) .

In particular, the first fin 11.1 (or the respective section 21), arranged between the other two fins 11.2, 11.3 of the tern, has a length LI (measured along the axis A and on the apical edge 15b), and the other two fins 11.2, 11.3 (or the respective sections 21), arranged on opposite sides of the first fin 11.1, have respective lengths L2, L3 (always measured along the axis A and on the respective apical edges 15b) .

The length LI is smaller than at least one of the lengths L2, L3 (in the example of Figures 1-2, smaller than both lengths L2, L3) .

According to the invention, the ratio R between the length LI and the sum of the lengths L2, L3 is lower than or equal to a predetermined threshold.

Specifically, the ratio R between the length LI, measured parallel to the axis A (in particular on the apical edge 15b), of the section 21 of the fin 11.1 and the sum of the lengths L2, L3, measured parallel to the axis A, of the sections 21 of the fins 11.2, 11.3 is lower than or equal to 0.40. This means that the fin 11.1 has a section 21 of length LI, which is lower than or equal to 40% of the sum of the lengths L2, L3 of the sections 21 of the fins 11.2, 11.3 adjacent and directly beside the fin 11.1.

Preferably, the ratio R is lower than or equal to 0.35, more preferably lower than or equal to 0.30.

In a preferred embodiment, the ratio R is lower than or equal to 0.25.

In another preferred embodiment, the ratio R is lower than or equal to 0.20.

In a further preferred embodiment, the ratio R is lower than or equal to 0.15.

The fin 11.1 is preferably arranged, as shown in the non limiting example of Figures 1-2, in a lower region of the element 1 (i.e. of the body 2), at least with its section 21.

In particular, the fin 11.1 or at least its section 21 are arranged mainly (i.e. with their more extended main part) or entirely in a lower half of the element 1 and of the body 2 (with reference to the normal position of use of the element 1 ) .

In other words, the fin 11.1 or at least its section 21 are arranged on the main portion 3 of the body 2, in a region of the main portion 3 comprised between the ends 5, 6 and therefore between the sleeves 4, and are closer to the lower end 6 in use (with reference to the normal position of use of element 1) .

Preferably, the fin 11.1 (namely its section 21) is spaced from both sleeves 4 but is closer to a first sleeve 4 arranged at the lower end 6.

In the preferred embodiment shown in Figures 1 and 2, the fin 11.1 is entirely arranged in a lower half of the element 1 and in particular of the body 2.

Each of the fins 11.2, 11.3 can be arranged on the side wall 7 (i.e. on the chamber 10) or on a partition 12.

Preferably, not only the fin 11.1 but also one or both the fins 11.2, 11.3 depart directly, at least in part, from the chamber 10, namely from the side wall 7 that delimits the chamber 10.

The fins 11 extend essentially longitudinal along the surface 13 and along respective axes substantially parallel to the axis A.

As already mentioned, each fin 11 (and therefore also each of the fins 11.1, 11.2, 11.3) can be continuous (as shown e.g. in Figures 1 and 2) or interrupted, having one or more transverse cuts that separate mutually longitudinally aligned portions of the fin (such as the rear end fin shown in Figures 1-2) . In other words, one or more of the fins 11.1, 11.2, 11.3 can be defined by respective rows of fin portions mutually aligned parallel to the axis A.

It is clear that if the sections 21 of one or more of the fins 11.1, 11.2, 11.3 are formed by a succession of fin portions, the respective lengths LI, L2, L3 are intended as the sum of the lengths of all the respective fin portions. The fins 11.2, 11.3 define, together with the fin 11.1 arranged between them, longitudinal channels, substantially parallel to the axis A and therefore substantially vertical in use, in which air moves.

In particular, a free channel 17, namely without obstacles formed by other fins or other components of the radiator 1, is defined above the section 21 of the fin 11.1 arranged between the fins 11.2, 11.3. The channel 17 extends vertically over the section 21 of the fin 11.1 (in this case, over the entire fin 11.1), is laterally delimited by the fins 11.2, 11.3 (i.e. by the respective sections 21) and is free of obstacles over the entire length of the fins 11.2, 11.3 laterally delimiting the channel 17.

The specific structure and arrangement of the fins 11 according to the invention improves the overall heat exchange efficiency of the element 1, even if in fact the available heat exchange surface is reduced (the fin 11.1 being significantly shorter than the fins 11.2, 11.3) .

The configuration of the invention, in fact, creates local motion conditions favouring the heat exchange.

In the solutions of the known art, above all in the (common) case of fins arranged close to each other (as in particular with fins starting from the water chamber) , the outermost fins exchange heat with the air efficiently, while the innermost fins work with lower efficiency, because in their upper part the rising air warms up and slows down, consequently reducing also the heat exchange in the lower part of the fin. The invention instead creates efficient and advantageous airflow conditions for heat exchange, even if the surface available for the heat exchange decreases, as confirmed by experimental results.

Further examples of radiator elements according to the invention, with fins 11 that are different but always satisfy the relationship indicated above, are schematically shown in Figures 3A-3C, 4A-4B, 5A-5D and 6A-6C.

In the embodiments of Figures 3A-3C, as already shown in the example of Figures 1-2, the element 1 further comprises (on each surface 13) a shorter fin lib, which starts from the side wall 7 of the chamber 10 and is flanked by two longer fins 11c. These fins are adjacent (i.e. directly facing) to the fin lib and are arranged on opposite sides with respect to the central fin lib, also starting, at least in part, from the side wall 7 of the chamber 10 (or are substantially tangent to it) . Therefore, the fins lib, 11c all contact directly, at least in part, the side wall 7 of the chamber 10.

The tern of adjacent fins 11 that satisfies the relationship of the invention is further formed by a tern of adjacent fins 11.1, 11.2, 11.3 defined respectively by the shorter fin lib and by the two longer fins 11c.

The examples shown in Figures 3A-3C differ in the different length LI of the section 21 of the fin 11.1 arranged between the fins 11.2, 11.3 (also in this case, but not necessarily, the section 21 coincides with the entire fin 11.1) . It is clear that also the fins 11.2, 11.3 may have respective sections 21 (always, but not necessarily, coinciding with the respective fins 11.2, 11.3) of different length L2, L3.

In the embodiments of Figures 4A-4B, the element 1 comprises a tern of adjacent fins 11 formed by a fin 11.1, starting from the side wall 7 of the chamber 10 (shorter fin lib), and two fins 11.2, 11.3 adjacent (i.e. directly facing) to the fin 11.1 and arranged on opposite sides of the fin 11.1 (longer fins 11c) . In this case, the fins 11.2, 11.3 are spaced away from the side wall 7 of the chamber 10 and start from respective partitions 12. Here too, the examples of Figures 4A-4B have fins 11.1 with sections 21 (coinciding with the respective entire fins 11.1) of different length LI.

In the embodiments of Figures 5A-5D, the element 1 comprises a group of four adjacent fins 11 arranged between two end fins, and precisely a pair of adjacent (directly facing each other) shorter fins lib, which start from the side wall 7 of the chamber 10 and are arranged between two longer fins 11c, arranged on opposite sides with respect to the pair of fins lib and adjacent (i.e. directly facing) to respective fins lib. Each of the fins 11c can be arranged directly on the side wall 7 of the chamber 10 or can be in contact with it (being for example substantially tangent to the side wall 7 of the chamber 10) or can be arranged on a partition 12 and spaced away from the side wall 7 of the chamber 10.

Also in these embodiments, the element 1 comprises at least one tern of adjacent fins 11, arranged side by side and having at least respective main longitudinal sections 21 substantially parallel to the axis A and substantially vertical in use, wherein the tern of adjacent fins 11 has a ratio R lower than or equal to the predetermined threshold indicated above.

In this case, the tern of adjacent fins 11 having lengths satisfying the numerical relationship indicated above comprises a first fin 11.1, which is one or the other of the two shorter fins lib, and the two fins 11.2, 11.3 adjacent thereto, consisting of the other shorter fin lib and of one of the longer fins 11c (Figure 5D) .

In the shown example, both terns of fins 11 formed by the pair of shorter fins lib and by one of the longer fins 11c have a ratio R lower than or equal to the predetermined threshold. However, it is clear that in accordance with the invention at least one tern of adjacent fins 11 has a ratio R that satisfies the aforementioned relationship.

The two fins lib may have the same length (as shown in Figures 5A-5D) or a different length.

Also in these embodiments, as in all the others previously described, a free channel 17, namely without obstacles formed by other fins or other radiator components 1, is defined above the fin 11.1 (or its section 21) arranged between the fins 11.2, 11.3.

In this case, the channel 17 extends over the fin 11.1, defined by one of the shorter fins lib, as well as over the adjacent fin 11.2, 11.3 defined by the other shorter fin lib. The channel 17 is laterally delimited on the one side by the other fins 11.2, 11.3, defined by the longer fin

11c, and on the opposite side by a further fin 11 that is, for example, the other longer fin 11c. In other words, the channel 17 extends over the two shorter fins lib and is laterally delimited by the two longer fins 11c.

In the embodiments of Figures 6A-6C, the element 1 comprises a single shorter fin lib on the side wall 7 of the chamber 10 and two longer (with respect to the shorter fin lib) fins 11c, arranged on opposite sides of the fin lib, adjacent (i.e. directly facing) to its respective faces 14 and arranged at least in part on the side wall 7 of the chamber 10 or in contact with it (in particular, substantially tangent to the side wall 7 of the chamber

10) .

Further fins 11 are arranged between at least one of the fins 11c and an end fin 11a, at different distances from the respective fin 11c.

In all cases, the element 1 comprises at least one tern of adjacent fins 11.1, 11.2, 11.3 (in this case, the tern formed by the shorter fin lib and by the two fins 11c immediately adjacent thereto) having a ratio R between the length LI of the section 21 of the first fin 11.1, in this case of the fin lib, and the sum of the lengths L2, L3 of the sections 21 of a second and third fins 11.2, 11.3, in this case of the fins 11c directly facing the fin lib, which is lower than or equal to 0.40, or 0.35, or 0.30, or 0.25, or 0.20 or 0.15.

Also in these other embodiments, the sections 21 of the fins 11 of the tern are entirely arranged in a region of the body 2 axially (i.e. along the axis A) comprised between a pair of axially opposite sleeves 4 (arranged at respective axial ends 5, 6 axially opposite along the axis A) .

Also in these embodiments, a free channel 17, namely without obstacles formed by other fins or other components of the radiator 1, is defined above the section 21 of the fin 11.1 arranged between the fins 11.2, 11.3. The channel 17 extends vertically above the section 21 of the fin 11.1, is laterally delimited by the sections 21 of the fins 11.2,

11.3 and is free of obstacles over the entire length of the sections 21 of the fins 11.2, 11.3 laterally delimiting the channel 17.

It is clear that the element 1 can comprise a different number of fins 11, variously spaced from each other and having different lengths with respect to what is described herein purely by way of example, but always with a tern or several terns of fins 11 arranged on the element 1 satisfying the above relationship.

It is also clear that the configurations described above and shown in the annexed figures may be combined together, so that further variants are also possible.

For example, the element 1 can comprise a group of one, two or more adjacent shorter fins 11, at least one of which and preferably all are arranged on the chamber 10. They are arranged between two longer fins 11 or between groups of longer fins 11, arranged on opposite sides of the group of shorter fins 11 and variously spaced from each other and from the chamber 10. Otherwise, the element 1 can also comprise alternating shorter and longer fins 11, alone or in groups .

In all cases, according to the invention, the element 1 comprises one or more terns of fins 11, formed by a first fin 11.1 and by a second and third fins 11.2, 11.3 arranged on opposite sides of the first fin 11.1, having at least respective main sections 21 entirely arranged in the region of the body 2 axially comprised between a pair of axially opposite sleeves 4 and having lengths satisfying the above mentioned relationship.

Even the general shape and structure of the element 1 may be different from what has been described up to now. In all cases, the element 1 has at least one tern of adjacent fins 11 protruding from a surface 13 of the element 1 and having a ratio R lower than or equal to the predetermined threshold indicated above.

For example, in the further embodiment shown in Figures 7- 8, the element 1 has a substantially plate-shaped body 2. The body 2 extends along a longitudinal axis A that, with reference to the normal position of use of the element 1, is substantially vertical. It comprises a substantially flat main portion 3 extending axially (along the axis A) between two opposite axial ends 5, 6 of the body 2 and laterally (i.e. transversely to the axis A) between two opposite side ends 5b, 6b (opposite in a direction orthogonal to the axis A) . The body 2 is provided with transverse connecting sleeves 4, arranged at at least one pair of opposite ends 5, 6 or 5b, 6b. In the non-limiting example shown, the body 2 has four sleeves 4 arranged at respective corners of the body 2, but it is clear that the body 2 can have sleeves 4 in different numbers and positions . The element 1 further comprises a plurality of fins 11, which project from a surface 13 of the body 2 and are substantially parallel to each other and to the axis A. In this case, the surface 13 defines a front or a rear surface instead of a side as in the previously described embodiments of the body 2.

The fins 11 may have different shapes and sizes, but the element 1 comprises at least one and, in this embodiment, several terns of fins 11 with a ratio R lower than or equal to the predetermined threshold indicated above.

Also in this case, for example, the fins 11 are of a generically quadrilateral shape, optionally with curved edges and/or rounded corners and optionally with one or more inclined sides with respect to the axis A.

For example, each fin 11 consists of a flat and thin lamina and has two opposite main faces 14, for example (but not necessarily) substantially flat and parallel, a root edge 15a joined to the body 2, an apical edge 15b having a free end, opposite the root edge 15a and for example substantially parallel to the root edge 15a, and a pair of side edges 16 joining the root edge 15a to the apical edge 15b.

Each fin 11 comprises at least one main longitudinal section 21 that is substantially parallel to the axis A and substantially vertical in use, for example substantially straight and preferably continuous. In the example shown in Figures 7-8, but not necessarily, each fin 11 coincides with the respective sections 21, i.e. each section 21 extends over the entire respective fin 11.

In particular, the element 1 comprises two series of fins lib, 11c having different respective axial lengths (measured parallel to the axis A, along the respective apical edges 15b) transversely alternated with respect to the axis A.

Therefore, the surface 13 has a succession of fins lib alternating with fins 11c, where the fins lib are shorter than the fins 11c.

It is clear that the element 1 may comprise fins 11 of different lengths, as well as of different shapes. In particular, the element 1 may comprise fins 11 having more than two different lengths, i.e. individual fins 11 or groups of fins 11 having three or more different lengths (e.g. in Figures 7-8 the element 1 comprises fins 11, in particular arranged at respective side ends of the body 2, having different lengths with respect to the two alternating series of fins lib, 11c) .

According to the invention, the surface 13 has a plurality of terns of fins 11 adjacent to each other and having a ratio R lower than or equal to 0.40, or 0.35, or 0.30, or

0.25, or 0,20 or 0.15. In this case, several terns of fins 11 satisfy the criterion of the invention, in particular, each tern formed by a fin lib (first fin 11.1) and by the pair of fins 11c (second and third fins 11.2, 11.3) arranged on opposite sides of the same fin lib and directly facing it.

In this case, the terns of fins 11 according to the invention have respective sections 21 entirely arranged in a region of the body 2 laterally included (i.e. transversely to the axis A) between a pair of laterally opposite sleeves 4 (i.e. arranged at respective opposite side ends 5b, 6b of the body 2) .

Above each section 21 of each fin 11.1 arranged between two adjacent fins 11.2, 11.3 it is defined a free channel 17, namely without obstacles formed by other fins or other components of the radiator 1. The channel 17 extends vertically above the section 21 of the fin 11.1, is laterally delimited by the sections 21 of the fins 11.2, 11.3 and is free of obstacles over the entire length of the sections 21 of the fins 11.2, 11.3 laterally delimiting the channel 17.

Finally, it is clear that further modifications and variations may be made to the radiator element described and shown herein without departing from the scope of the appended claims.

Claims

1. A heating radiator element (1) comprising a body (2) extending substantially along a longitudinal axis (A) and having at least one pair of transverse connecting sleeves (4) for the connection to other radiator elements and/or to a hydraulic circuit, arranged at respective ends (5, 6; 5b, 6b) of the body (2), and a plurality of heat exchange fins (11) arranged on at least one surface (13) of the body (2); said fins (11) comprising at least a tern of adjacent fins (11.1, 11.2, 11.3), arranged side-by-side and having at least respective main straight longitudinal sections (21) parallel to each other and to the axis (A) and vertical in use, arranged in a region of the body (2) axially or laterally comprised between a pair of opposite sleeves (4), positioned at respective opposite ends (5, 6;

5b, 6b) of the body (2); the tern of adjacent fins (11.1,

11.2, 11.3) being formed by a first, a second and a third fins (11.1, 11.2, 11.3), wherein the first fin (11.1) is arranged between the second and the third fins (11.2, 11.3) and the second and the third fins (11.2, 11.3) are arranged on opposite sides of the first fin (11.1) and directly facing the first fin (11.1); characterized in that the ratio (R) between the apical axial length (LI) of the longitudinal section (21) of the first fin (11.1) and the sum of the apical axial lengths (L2, L3) of the longitudinal sections (21) of the second and third fins

(11.2, 11.3) is lower than or equal to 0,40.

2. A radiator element according to claim 1, wherein said ratio (R) is lower than or equal to 0.35.

3. A radiator element according to claim 1, wherein said ratio (R) is lower than or equal to 0.30.

4. A radiator element according to claim 1, wherein said ratio (R) is lower than or equal to 0.25.

5. A radiator element according to claim 1, wherein said ratio (R) is lower than or equal to 0.20.

6. A radiator element according to claim 1, wherein said ratio (R) is lower than or equal to 0.15.

7. A radiator element according to any one of the preceding claims, wherein the first fin (11.1), or at least the longitudinal section (21) thereof, is arranged mainly or completely, with reference to the normal position of use of the element (1), in a lower half of the element (1) and in particular of the body (2) and is closer to a first end (6) , lower in use, of the body (2) .

8. A radiator element according to any one of the preceding claims, wherein the body (2) is provided with an inner chamber (10), delimited by a side wall (7), for the circulation of a heating fluid; and the first fin (11.1) projects from the side wall (7) delimiting the chamber

(10) .

9. A radiator element according to claim 8, wherein the second and third fins (11.2, 11.3) project directly, at least partially, from the side wall (7) delimiting the chamber (10).

10. The radiator element according to any one of the preceding claims, comprising two or more terns of adjacent fins (11.1, 11.2, 11.3) having a ratio (R) lower than or equal to 0.40, or 0.35, or 0.30, or 0.25, or 0.20 or 0.15.

11. The radiator element according to any one of the preceding claims, wherein the tern of adjacent fins (11.1, 11.2, 11.3) is formed by a first shorter fin (11.1) arranged between a second and a third fins (11.2, 11.3) longer than the first fin (11.1) .

12. The radiator element according to any one of the preceding claims, wherein a free channel (17) extending vertically above said longitudinal section (21) of the first fin is defined above the longitudinal section (21) of the first fin (11.1) and is laterally delimited by a pair of fins (11) parallel to each other and to the axis (A) and defined by said second and third fins (11.2, 11.3) or by one of said second and third fins (11.2, 11.3) and by a further fin (11) not being part of the tern of fins (11.1, 11.2, 11.3) and parallel thereto; the channel (17) being free of obstacles over the entire length of the fins (11) laterally delimiting the channel (17) .