Radiating element for energizing heating device and use thereof

Abstract

The invention relates to a radiating element (1) for heat treatment in at least one furnace, and / or for continuous galvanization and annealing lines of metal strips or plates and / or other products made of steel and / or other metals, and / or for modernization of at least one pre-existing furnace, the radiating element (1) being intended to emit and / or radiate heat, the invention relates to a radiation element (1) having a main longitudinal extension (L) and a transverse extension (M) perpendicular to the main longitudinal extension (L), and comprising a shaped wall (2) defining an outer surface (3b), an inner surface (3a) and an inner cavity (4), the radiation element (1) further comprising at least two main hollow seats (5) adapted, in use, to receive at least one heating device (10), and at least one connecting seat (6); a radiating system and a use of the radiating element (1).

Description

Technical Field

[0001] The invention relates to a radiation element for industrial equipment or the like, which is electrically driven or generally powered by means of a heating device and which can be used in the field of furnaces or equipment for heat treatment of steel and / or other metals.

[0002] More specifically, the invention relates to an electrically driven or generally powered and / or heated radiant element, which can generally be used in heat treatment furnaces and / or in continuous galvanizing or continuous annealing lines (CGL, AGL, CAPL or CAL lines, etc.) for strips or plates made of metal sheets, bolts, cables, pipes, components for pipes, as well as the installation, processing and production of "advanced high strength steel" (AHSS) and new steel grades and / or other products made of other metals.

[0003] Furthermore, the radiant element according to the invention can be used both in new continuous galvanizing and continuous annealing lines and in the retrofitting of old furnaces of continuous galvanizing and continuous annealing lines and in general in any furnace for heat treatment.

[0004] Therefore, the present invention has applications in the automotive industry and the steel and / or aluminum industry, among others. Background Art

[0005] The increasing severity of climate change and the resulting need to reduce NOx and CO2 emissions into the atmosphere has forced the industry in general, and steel producers in particular, to take a series of substantial actions globally to achieve this goal in a short period of time.

[0006] It is well known that most iron materials or aluminum alloys and other materials suitable for producing parts needed in daily life are heat treated during their functional life to obtain better durability, higher hardness and / or longer performance.

[0007] In this sense, in the steel / automotive industry and in general, heating furnaces are used for heat treatment of materials at high temperatures (from 200°C to over 1200°C), and therefore they are sold and used in many types of industries.

[0008] Today, heat treatment, for example of metal sheets and their derivatives, is mainly carried out by heating with radiant tubes of any shape (W or M, U, double P and single P, I, L or any other geometry), so that the metal sheet passing in the form of a continuous belt can be subjected to the required heat treatment.

[0009] The materials used to manufacture these radiant tubes have the property of resisting temperatures up to 1200°C and above (if the radiant tubes are made of ceramic material, thermal resistances up to 1500°C can be obtained).

[0010] These tubes are usually connected to a gas burner (or also using other fuels such as hydrogen, methane or others) which generates the temperature and power required for its operation and the treatment to be performed.

[0011] These systems require a flame inlet area (burner side), a smoke channel area (for heating the radiant tubes) and a smoke outlet area with a recovery unit (for reducing the very high emissions inside the tubes and for possibly recirculating part of the smoke to enable it to be reburned, thus reducing the final emissions).

[0012] These burners emit very hot flames (up to 1300°C and above) inside radiant tubes which heat by radiation (hence the name radiant tubes) the strip, for example a metal sheet, passing through the furnace until the desired treatment is achieved in order to obtain each single and specific "Grade" according to the future operating characteristics of the various products to which the strip itself will be applied.

[0013] All of these fuel systems currently in use emit very high levels of exhaust gases into the atmosphere, especially NOx and CO2.

[0014] For example, if the European Community has set an emission range of 100 mg / m 3 Up to 300 mg / m 3 , and each European country can decide the minimum and maximum values ​​allowed, then in Europe, the United States and other parts of the world, there are many factories that greatly exceed the above values, even up to 350mg / m 3 Up to 500 mg / m 3 and above levels.

[0015] Many efforts have been made to reduce these emission levels, but despite the importance of the efforts made by all companies in the sector, it is increasingly difficult to obtain satisfactory and lasting results due to the systems themselves (burners, gases, flue gas recirculation systems in ducts, radiation, heat recovery, etc.).

[0016] In fact, one of the problems of flame burners is to maintain the combustion parameters precisely over time so that there are constant and controllable emissions. The "decomposition" (loss) of the use parameters (adjustments) involves constant maintenance and control requests, otherwise, in almost all cases, a rapid return to the basic conditions leads to an increase in emission parameters over time (too high according to current regulations).

[0017] This inconvenience forces steel producers to invest heavily in the control and continuous regulation ("tuning") of burners and combustion systems. In addition, the loss of the basic parameters for optimal combustion usually leads to greater aggressiveness of the burner flame, serious life problems of the heat radiant tubes through deformation of the hottest parts (usually on the burner side), cracking of the material itself and of the welds, and the need for constant spare parts and line stops (furnaces) to replace damaged parts.

[0018] There are also furnaces equipped with a plurality of heating elements of the electric type, wherein the heating elements are preferably operated with high kilowatt values ​​in order to keep their number and size, as well as the size of the furnace itself, to a minimum. Typically, the heating elements operate inside a tubular container which protects the heating elements themselves from the gases in the furnace.

[0019] However, these heating elements must operate at high power and high power density (measured in watts per square centimeter of conductive element surface area) to provide the furnace with the power it needs to work internally, which results in a high risk of short circuits or system failure.

[0020] Even increasing the number of heating elements would not solve the problem, as this would require increasing the size of the furnace, thereby increasing any losses and associated operating costs, not to mention the fact that existing furnaces are generally not equipped to support such an increase.

[0021] Document US5473141 discloses a heating assembly for use inside an electric furnace radiator. The heating element of the heating assembly is shaped like a rod and is mounted on a ceramic insulating disk that supports the rod element itself. There may be a single tube cover to protect the heating element.

[0022] Document US5083012 discloses a single-tube heating element for a furnace comprising a cable resistor, wherein the resistor comprises a plurality of cables connected in parallel to provide high power while keeping the power density below a safety threshold.

[0023] It can thus be seen that there is a strong need to provide a radiant element which is electrically driven or generally powered by means of a heating device, which overcomes the above-mentioned disadvantages of the prior art. Summary of the invention

[0024] Therefore, the technical task of the present invention is to improve the state of the art.

[0025] Within the scope of this technical aim, an object of the present invention is to provide a radiating element that allows reducing or eliminating emissions, such as NOx and CO2, caused by thermal treatment lines in any sector, from automotive to steel, aluminium, etc.

[0026] Another object of the invention is to provide a radiant element that allows a reduction in the aggressiveness of the heat generated with respect to known systems with burners, while maintaining excellent heat radiation and / or heat transfer capabilities.

[0027] Another object of one version of the invention is to provide a radiation element which, in the field of heat treatment, no longer requires a burner powered by any fuel, but is powered in another way, for example electrically, for example by an electric drive by electric induction.

[0028] Another object of the invention is to provide a radiating element capable of ensuring an increased thermal efficiency and a uniform temperature (achieved by increasing the temperature if necessary) along the entire surface of the radiating element itself.

[0029] Another object of the invention is to provide a radiant element capable of lasting longer and having a longer life than traditional radiant tubes, since it guarantees temperature uniformity along its entire extension, making it possible to undergo the same expansion and return movements during the temperature changes required for the thermal treatment of the material, effectively reducing the stresses and cracks or tears to which the material constituting the radiant element itself may be subjected.

[0030] This aim and objects are achieved by a radiating element according to the attached claim 1 .

[0031] Further advantageous features are described in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] A person skilled in the art will better understand the characteristics of the present invention from the following description and the accompanying drawings given as non-limiting examples, in which:

[0033] Figure 1 is a side view of a version of a radiating element according to the invention,

[0034] Figure 2 yes Figure 1 Rear view of the radiating element,

[0035] Figure 3 is a perspective view of a version of a radiating element according to the invention,

[0036] Figure 4A is a side view of another version of a radiating element according to the invention,

[0037] Figure 4B It is along Figure 4A A cross-sectional view taken along the trace plane CC;

[0038] Figure 4C yes Figure 4A A front view of a portion of a radiating element, in which the support of the radiating element itself can be seen,

[0039] Figure 4D yes Figure 4A Rear view of the radiating element,

[0040] Figure 5A and Figure 5B Two resistors or resistances are shown, each with an electrical cable and an electrical plate,

[0041] Fig. 6A and Figure 6B A side view and a side view of a version of a radiating element according to the invention are shown respectively. Fig. 6A A cross-sectional view taken from the trace plane DD,

[0042] Fig. 7A and Figure 7B A side view and a side view of a version of a radiating element according to the invention are shown respectively. Fig. 7A A cross-sectional view taken from the trace plane DD,

[0043] Fig. 8A and Figure 8B Two perspective views of another version of a radiating element according to the invention are shown. DETAILED DESCRIPTION

[0044] With reference to the accompanying drawings, 1 denotes a radiant element which can be used in a heat treatment furnace and / or in a continuous galvanizing and annealing line for metal strips or plates and / or other products made of steel and / or other metals, in particular CGL, AGL, CAPL or CAL lines, etc., and / or for the modernization of previous furnaces.

[0045] The invention also relates to a complete radiation system, thus to a radiation and heating system, of which the radiation element 1 is a part, and to at least one heating device 10, for example at least one electrically or fuel-driven heating device.

[0046] At least one heating device, for example an electric or fuel-driven heating device, is a heating device for the radiant element 1. In fact, it is capable of heating the radiant element, for example to more than 1200° C., and allowing the latter to emit / radiate heat to the outside (for example towards the metal strip passing in its vicinity for the desired heat treatment), so as to perform the heat treatment itself.

[0047] In its electrically driven version, the at least one heating device 10 comprises or is in the form of at least one electrical resistance (also referred to as resistor, for example).

[0048] The at least one electrically driven heating device 10 can be inductive or have at least one inductor.

[0049] In an alternative, the heating device 10 is fuel driven, ie it is a burner driven, for example, by gas, hydrogen, methane, biofuels, zero emission fuels, e-fuels, carbon neutral synthetic fuels or the like.

[0050] In at least one version of the invention, as better described below, the radiant element comprises and houses at least one heating device 10 .

[0051] The use of electrical resistors is common in heating, for example in domestic or work environments (offices and large sheds). However, in this case, the power used and especially the temperatures obtained are very low, since their purpose is to heat rooms for normal everyday life.

[0052] However, in the field of processing general materials (steel, aluminum, copper, etc.), as mentioned above, very high powers and especially extremely high temperatures (up to 1200° C. and above if necessary) are required.

[0053] Therefore, the at least one heating device according to the invention must be able to ensure the power and reach the temperature required for the above-mentioned operation.

[0054] Due to its weight, construction and the material from which it is made, the thermal expansion of the resistor is different from the thermal expansion of the material from which the resistor is made or from which the radiating element 1 is made.

[0055] In fact, the radiating element according to the invention can be obtained from a metal plate with or without high or low nickel, molybdenum or cobalt alloys, such as Inconel 600 / 601 / 602, Avesta, Alloy 800H, AISI 309 / 310 / 316 / 321, Kanthal APM / APM-T, A1, or from at least one material obtained by melting / casting, forging, extrusion or other or any other material that can be used for this purpose.

[0056] The radiating element according to the invention has a completely innovative shape and design.

[0057] This is also related to the fact that, in at least one of its versions, independently of the burner used for its heating, it no longer requires one or more inlet areas for smoke and / or flames heated by the burner, nor one or more smoke outlet areas. Nevertheless, the radiant element according to the invention is an element capable of determining thermal radiation / irradiation and achieving all the desired advantages in terms of energy efficiency, heat transfer and reduction or elimination of harmful emissions, in particular such as NOx and CO2.

[0058] In particular, the radiating element 1 has a substantially hollow shape having a main longitudinal extension L (or length) and a transverse extension M (or width).

[0059] In particular, "longitudinal" refers to a direction or plane extending along a main and / or primary direction of the radiating element 1, whereas "transverse" refers to a direction or plane extending along a direction perpendicular to the longitudinal direction.

[0060] The radiating element 1 comprises a shaped wall 2 defining an outer surface 3b and an inner surface 3a, and an inner cavity 4.

[0061] The inner surface 3a faces the inner cavity 4. The outer surface 3b opposite to the inner surface 3a faces the object to be treated in use.

[0062] The inner cavity 4 extends substantially along the entire longitudinal extension L of the radiating element 1. In particular, at least two main hollow seats 5 can be identified in the cavity 4. The main hollow seats 5 have a pattern parallel to each other and to the main extension L of the radiating element 1 .

[0063] The cross section of each main hollow seat 5 has a circular or polygonal shape, such as a square, a rectangle, a prism, a hexagon, an octagon, or the like.

[0064] The inner cavity 4 also defines and / or comprises at least one connecting seat 6 capable of connecting at least two main hollow seats 5. Preferably, the connecting seat 6 is hollow. In an alternative version, the connecting seat 6 is closed or full.

[0065] The at least one connecting seat 6 is arranged parallel to the at least two main hollow seats 5 and therefore also extends substantially along the longitudinal extension L of the radiating element 1 .

[0066] At least one connection socket 6 has a substantially polygonal cross section, for example a rectangular or square one.

[0067] The length of the main hollow seat 5 and / or the connecting seat 6 substantially corresponds to the length of the radiating element 1 .

[0068] In at least one version of the invention, the connecting seat 6 is in fluid connection with at least two main hollow seats 5. In fact, at least in this version, the inner cavity 4 is unique and is formed by the inner hollow space of at least two main hollow seats 5 and at least one connecting seat 6.

[0069] Taking into account the lateral extension M of the radiating element 1, at least two main hollow seats 5 and at least one connecting seat 6 are arranged in the same plane. They are therefore coplanar. The radiating element itself is coplanar, ie it has a substantially flat extension.

[0070] Typically, the main hollow seat 5 is placed on the outer longitudinal side of the radiating element 1 .

[0071] According to at least one version of the invention, there is at least one (internal) passage or connection port or opening 7 between the main hollow seat 5 and the connection seat 6 , which puts the seats 5 , 6 in communication, for example in fluid communication.

[0072] According to one version of the invention, these ports or openings 7 are arranged in the same plane, for example parallel to the plane defined and / or in which the main hollow seat 5 and the connecting seat 6 are located.

[0073] The ports or openings 7 are internal, in that they do not involve the wall 2 of the radiating element 1 .

[0074] In fact, in at least one version of the invention, the wall 2 of the radiating element is continuous and, at least as far as the longitudinal extension L and the transverse extension M are concerned, has no openings that could put the internal cavity 4 in communication with the outside.

[0075] In alternative embodiments where the connection seats 6 are closed or filled, the main hollow seats 5 are not fluidically connected via the connection seats 6 and may or may not be fluidically connected to each other.

[0076] The radiating element 1 also has two lateral ends 8 , which are situated on opposite sides of the longitudinal extension L of the radiating element 1 .

[0077] In at least one version of the invention, the end 8 is closed. In particular, as will be better understood below, the end 8 of the radiating element 1 is closed on one side by a containing element or pad 12 and on the other side by a closing plate 15, which will be better defined below.

[0078] At the transverse ends 8, the radiating element 1 may be connected and / or positioned, in use, on at least one wall or both walls of a furnace, the radiating element being positioned inside the furnace.

[0079] In particular, according to at least one version of the invention, there is a first transverse end 8a positioned at the first wall of the furnace in use, in which there is a support called "furnace side" or "socket" 20, taking into account the traditional name of furnaces equipped with burners or other systems that do not require classic flame burners, regardless of the presence or absence of smoke recuperators (of course, in the case of the present invention, the burners and the systems will not be present or will not be started, since according to the invention they are powered in a different way and / or electrically).

[0080] In at least one version, the socket 20 conventionally consists of a support fixed to the first wall of the furnace.

[0081] In particular, according to at least one version, the radiating element is equipped with a support 9 for the radiating element (placed at the first lateral end 8a of the radiating element itself, for example fixed and / or constrained to the closing plate 15), which support 9 can be supported by and / or moved on the socket 20. The socket 20 may comprise at least one section or surface or compartment that is generally capable of contact with the support 9. The socket 20 and / or the support 9 may be made of a metallic material resistant to high temperatures, such as: austenitic steel material, high or low nickel content (or high nickel alloy) or molybdenum or cobalt steel material, ceramic material, silicon carbide material, the same material as the radiating element 1, etc.

[0082] The thermal expansion of these materials ranges from 0 mm to 20 mm or more, depending on the temperature of use and their construction.

[0083] In use, for example, the support 9 can be placed on an internal socket 20 of an already existing furnace.

[0084] According to at least one version of the invention, the shape and dimensions of the support 9 of the radiating element 1 depend on the shape and positioning of the sockets 20 already present in the furnace.

[0085] In particular, the support 9 can have a configuration protruding from the radiating element 1, a tubular or curved or flat configuration, in the last two cases, considering a base surface that rests on a corresponding surface of the socket 20 and depending on the type of socket 20 to which the radiating element 1 can be applied and / or connected.

[0086] For example, from Figure 4C It can be seen that the support 9 can have a support base for the socket 20, which has a curved shape, wherein the recess is away from the socket 20 itself. Such a configuration of the support 9 can also be defined as a U-shape.

[0087] Precisely because the support 9 depends on the type of socket 20 in which it will be inserted and / or rest, the support 9 can be positioned at a variable point of the first end 8a and / or can be formed by a single element or several elements (even one in each main hollow seat 5).

[0088] Furthermore, according to at least one version of the invention, as described above, at least one closing plate 15 may be present in at least one of the ends 8 of the radiating element 1, for example at the first end 8a of the radiating element 1. The closing plate 15 may be a section of sheet metal (e.g. the same material as the radiating element 1) having a straight or curved shape or other shape.

[0089] If a support 9 is present, the closing plate 15 will be able to be received and connected to the support 9 and will be able to support (or help support) the weight of the radiant element 1 and the at least one heating device 10 contained therein.

[0090] The radiant element 1 also has a second transverse end 8b which can be connected and / or positioned at a second wall of the furnace, for example a wall on the side of the furnace opposite to the first wall (the latter being equipped with a furnace side support or socket 20). The burner is traditionally located in the second wall of existing furnaces, for example in a rear position relative to what is defined in the present invention as a housing element or pad 12, which has already been mentioned and better described below.

[0091] In fact, the radiant element 1 according to the invention can also be adapted and connected to the wall of existing furnaces, usually equipped with radiant tubes of conventional type, using hooks already present in the furnace, the so-called furnace-side sockets / supports 20. In this way, in the case of a complete retrofit of a production line, the user can reduce costs, since these furnaces can be implemented with only heating means other than conventional ones, for example with the current discharge system required for the operation of the electrically driven heating means 10.

[0092] According to one version of the invention, for example Figure 1 , Figure 3 , Fig. 6A and Fig. 7A As shown, the radiation element 1 includes six main hollow seats 5 and five connecting seats 6 .

[0093] In another version of the invention, for example Figure 4A , Fig. 8A and Figure 8B As shown, the radiation element 1 includes three main hollow seats 5 and two connecting seats 6 .

[0094] In another version of the invention, two or more radiating elements 1 (for example a first radiating element or upper radiating element and a second radiating element or lower radiating element) can be associated in the same furnace seat (or in the same pad, as described below), each radiating element being equipped with several main hollow seats 5 and one, two or more connecting seats 6.

[0095] According to one version of the invention, both the upper and lower radiating elements comprise three main hollow seats 5 and two connecting seats 6, and each contains three resistors.

[0096] In this way, the weight of the entire system is also distributed.

[0097] A (free) space of between 5 cm or 2 cm to 10 cm or 1 cm to 50 cm can be maintained between the upper and lower radiating elements. In this way, sufficient space is provided to anticipate a possible droop or drop of the upper radiating element. This can further extend the lifetime of the radiating element according to the invention.

[0098] In this case, or according to another variant of the invention, if desired it can also be decided to keep only some of the heating devices 10 present functional, ie a heating device such as a radiant element is operating while the heating device of another heating device is switched off.

[0099] Furthermore, a heating device of a certain size and / or power can be positioned at at least one main hollow seat 5, and at least one (another) heating device can be smaller in size and / or power than other heating devices installed in the same radiation element, in at least one other main hollow seat 5, for example a main hollow seat 5 positioned at the lowest part in use of the radiation element itself.

[0100] In this way, the weight and / or deformations caused by the at least one heating device 10 can be reduced in those parts of the radiant element which are on the contrary more susceptible to deformation due to the weight and / or temperature determined exactly by the at least one heating device 10 .

[0101] Of course, due to the characteristics of the present invention, the uniformity of heating can be ensured in any case, thereby ensuring the uniformity of heat treatment.

[0102] Alternatively, when several radiation elements 1 are associated in the same seat of the furnace (or as will be seen below in the same pad), at least one or more radiation units 1 may be equipped with less than three or more than three main hollow seats 5; the number of connecting seats 6 depends on the number of main hollow seats 5. For example, according to at least one version of the invention, if the number of main hollow seats 5 is n, and n is greater than or equal to 2, the number of connecting seats 6 is n-1.

[0103] According to another version of the invention, there are two main hollow seats 5 and one connecting seat 6, or four main hollow seats 5 and three connecting seats 6, eight main hollow seats 5 and seven connecting seats 6, and so on.

[0104] In at least one version of the invention, the main hollow seat has a substantially cylindrical or parallelepiped shape; the connecting seat 6 may have a parallelepiped shape with a polygonal, rectangular or square base.

[0105] Typically, the width of the at least one main hollow seat 5 , viewed in the transverse direction M of the radiating element 1 , is greater than the width of the at least one connecting seat 6 .

[0106] exist Fig. 8A and Figure 8B 1, the width of at least one main hollow seat 5 is smaller than the width of at least one connecting seat 6, viewed in transverse direction M of the radiating element 1. However, this version of the invention is dedicated to the specific needs of a furnace in which the corresponding radiating element is installed.

[0107] According to at least one version of the invention, also viewed from any port or opening 7 , the connection seat 6 is formed and / or defined by two sections 6 a , 6 b of the wall 2 having an extension parallel to the substantially rectangular longitudinal portion L and overlapping each other.

[0108] If desired, these sections 6 a , 6 b may be connected uninterruptedly and / or integrally to at least one portion 5 a of a wall 2 or to at least two portions 5 a , 5 b of a wall 2 forming and / or delimiting each main hollow seat 5 .

[0109] According to at least one version of the invention, at least one portion 5a or both portions 5a, 5b have, in use, a recess towards the interior of the radiating element and / or towards the inner cavity 4.

[0110] In particular, the main hollow seat 5 connected to the single connecting seat 6 has a single portion 5a having a substantially circular or polygonal cross section corresponding to the cross section of the main hollow seat 5, but which is open in cross section at at least one port or opening 7.

[0111] These main hollow seats 5 are the outermost seats located on the outer longitudinal sides of the radiating element 1 .

[0112] On the contrary, if present, the main hollow seat 5 is connected to two connection seats 6, which are connected one to the other, viewed from the transverse extension M of the radiating element 1, the main hollow seat 5 being formed and / or defined by two portions 5a, 5b, each of which has a circular sector section or a polygonal portion, so as to form together the corresponding cross section of the main hollow seat 5. Similarly, there will be two ports or openings 7, forming a kind of completion with the portions 5a, 5b of the cross section of the main hollow seat 5. These ports and openings 7 will be located on opposite sides, viewed from the main hollow seat 5 and from the transverse extension M of the radiating element.

[0113] Obviously, in the version where the connection seat 6 is closed or filled, the cross section of the main hollow seat 5 is determined by the portions 5a, 5b and the possible inner surface of the closed connection seat 6 (together with the sections 6a, 6b), preventing fluid from connecting with the main hollow seat 6.

[0114] In particular, segment 6a and portion 5a constitute a first main surface or front surface of the radiating element, while segment 6b and portion 5b constitute a second main surface or rear surface of the radiating element; the longitudinal side of the radiating element 1 generally consists of at least one portion 5a having a transverse structure substantially corresponding to the cross-section of at least one main hollow seat 5.

[0115] According to at least one version of the invention, the thickness W of the radiating element is not constant. In fact, the thickness may be understood as, for example, the distance W1 between the segments 6a, 6b or the distance W2 between the portions 5a, 5b. The distance W2 is greater than the distance W1.

[0116] According to at least one version of the invention, thickness W2 corresponds to the diameter of the circular section of main hollow seat 5 .

[0117] According to at least one version of the invention, thickness W1 corresponds to the width of opening or port 7 .

[0118] Furthermore, according to at least one version of the invention, the thickness of wall 2 is approximately 5 mm.

[0119] In fact, at least according to one version of the invention, the connection seat 6 is ideally formed by four longitudinal sides, two parallel and opposite longitudinal sides of which are formed by the sections 6a, 6b and the other two by the ports or openings 7, thereby forming in fact an empty space inside the cavity 4.

[0120] According to an alternative version, the connection seat 6 is formed by four longitudinal sides, of which two parallel and opposite sides are formed by the segments 6 a , 6 b and the other two are formed by inner surfaces which in fact respectively connect the seat 6 .

[0121] On the other hand, regarding the wall 2 of the radiating element 1, it is formed from a single piece of material constituting the radiating element 1, for example from a shaped sheet, and is composed of sections 6a, 6b and parts 5a, 5b. In particular, the wall 2 extends corresponding to the radiating element 1 and is able to enclose the inner cavity 4.

[0122] The wall 2 is made in a single piece, ie it is made by shaping (at least) a single piece of sheet metal which is joined together, for example by welding, to create the desired closed configuration for the radiating element 1 .

[0123] According to an alternative version, the wall 2 is made by joining together, for example by welding, several pieces of material constituting the radiating element 1 , for example two half-shells, a front half-shell and a rear half-shell, so as to give it a configuration identical to the desired configuration.

[0124] As previously mentioned, the wall 2 is shaped so as to have a longitudinal projection corresponding to the main hollow seat 5 and even more specifically to its portions 5a, 5b.

[0125] The wall 2 also has, between one portion 5 a , 5 b and the other portion, a section which corresponds substantially to the sections 6 a , 6 b of the connection socket 6 .

[0126] The sections 6 a , 6 b forming the connection seat 6 can be flat, slightly hollow, slightly convex or protruding relative to the cavity 4 .

[0127] This shape of the wall 2 corresponds to both the outer surface 3 b and the inner surface 3 a of the wall 2 .

[0128] The fact that the wall 2 is continuous and / or full, ie has no holes or empty areas, makes the radiating element 1 more efficient.

[0129] For example, we can consider traditional radiant tubes: they consist of straight tubes whose ends are connected by curved tubular elements for the recirculation of smoke. In addition, between one straight tube and another (mainly P, double P, U and double U configurations) there are "blank" areas, which are at a certain distance from the straight tubes themselves, determining whether there are "blank areas" that do not contribute to the emission and / or radiation of heat, which are precisely "blank" and are not made of the material from which the radiant tube is made. This leads to the low efficiency of traditional radiant tubes.

[0130] The same applies to the individual tubular elements which are in any case spaced apart from one another.

[0131] Furthermore, for a conventional radiant tube fed by a fuel burner, the temperature is not uniform along its longitudinal extension: in fact, there are very hot areas (burner / flame side), areas with a constant drop in temperature (smoke channel area) and cooler areas (smoke outlet side).

[0132] The radiant element according to the invention does not suffer from these drawbacks and therefore the heat transfer is increased (compared to traditional systems) precisely due to the fact that the wall 2 is continuous and "full"; moreover, in one version, a uniform temperature is obtained along the entire surface or wall 2 of the radiant element, from one side to the other and from one transverse end 8a to the other transverse end 8b, thanks to the absence of a burner and the presence of at least one heating device 10.

[0133] This advantage can also be achieved when the heating means 10 are supplied with fuel, since they are at least partially housed inside the main hollow seat 5, they contribute to improving the uniformity of heating along the entire surface or wall 2 of the radiant element, from one side to the other and from one transverse end 8a thereof to the other transverse end 8b.

[0134] Furthermore, due to the difference in heating and / or power supply, the temperature that can be reached by the wall 2 can also be increased, thereby also increasing the heat and heat transfer efficiency of the radiating element 1 according to the invention towards the strip.

[0135] In at least one version of the invention, the heating device 10 is not a burner.

[0136] Furthermore, thanks to these advantages, the life of the radiating element 1 is also extended, since the materials of which it is made and composed have the possibility of undergoing the same expansion and return movements during the temperature changes required for the thermal treatment, thus reducing the probability of tearing (cracks) and generating stresses in the material itself. Of course, by reducing these risk factors for the integrity of the radiating element, a longer life can be determined.

[0137] Likewise, the above-mentioned improvements of the invention make it possible to reduce power consumption and heating consumption. In fact, by increasing the heat exchange surface (compared to traditional types of radiant tubes), less energy (lower temperatures) is required to obtain the same heat discharge effect. In addition, the temperature uniformity over the entire surface of the radiant element obtains a better uniformity and quality of the heat treatment of the strip or metal sheet, also enabling the development of new steel grades for each type of market.

[0138] As mentioned above, the radiation element 1 comprises and houses at least one heating device 10, for example an electrically driven or fuel driven heating device, to form the system of the invention. The at least one heating device 10 is housed in at least one main hollow seat 5. In particular, each main hollow seat 5 can contain at least one device 10.

[0139] At least one heating device 10 is removable, ie in the event of a default or inoperable condition it can also be replaced individually.

[0140] Furthermore, the presence of the device 10 allows for easier control of the thermal treatment since, in a particular version, the current is constant in its use, unlike burner systems which, as previously mentioned, require continuous control of adjustments and emissions also caused by the imbalances caused by the various gases and fuels (combustion) on the market, which significantly reduces management costs compared to current burner systems.

[0141] As expected, these new radiant elements make it possible to reduce and / or eliminate harmful emissions such as NOx and CO2, while reducing the risks to the environment and to the operators who have to look after the furnace and / or perform maintenance on it, precisely because the environment inside the furnace is free of these harmful substances, which reduces the risk of poisoning due to inhalation of toxic gases and fumes.

[0142] The fact that at least one device 10 is contained within at least one main hollow seat 5 allows to concentrate all the technologies required for its heating with a single element such as the radiating element 1 and to obtain maximum performance in terms of energy / heat transfer, temperature uniformity and extending the life of the radiating element itself.

[0143] The shape of the at least one main hollow seat depends on the shape and / or power of the at least one device 10 , for example at least one electrical resistance or fuel burner.

[0144] In fact, in order to determine which and how many devices 10 are to be placed inside the radiating element, it is necessary to consider which temperature level must be reached in order to carry out a specific thermal treatment.

[0145] According to the radiation element 1 of the present invention, in order to accommodate at least one heating device 10 therein, it further comprises at least one reinforcing device 11, preferably, the reinforcing device 11 is positioned inside at least one main hollow seat 5 and / or inside the connecting seat 6. The purpose of the reinforcing device 11 is to assist in supporting and / or fixing the position of at least one device 10.

[0146] The reinforcement means 11 comprises at least one plate, screw, bolt, rod, pin, peg or other similar reinforcement member; they can be fixed, welded or press-fitted on the inner surface 3a and / or outer surface 3b of the radiating element 1 and / or on at least one of the sections 6a, 6b of at least one connecting seat 6 and / or on the parts 5a, 5b of at least one main hollow seat 5. Preferably, the reinforcement means 11 is internal or mostly internal.

[0147] The at least one reinforcing device 11 may have a cylindrical, conical, flat, parallelepiped, prismatic or other shape.

[0148] According to a particular version of the invention, at least one reinforcement means 11 is positioned (internally) at the section 6a and / or section 6b of at least one connection seat 6. In this way, it is possible to reduce the amplification (expansion) effects of the radiating element itself, as well as the sagging and deformation effects of its constituent materials.

[0149] According to at least one version of the invention, the reinforcement means 11 are multiple or serially connected and are positioned spaced apart from one another along the entire longitudinal extension of the radiating element 1, preferably at the connection seat 6, or at least at the connection seat. For example, such reinforcement means are Figure 4B As can be seen from this exemplary image, according to one version of the invention, the reinforcing means 11 are shaped like a pin, the ends of which are fixed to each section 6a, 6b of the connection seat 6.

[0150] For example, Fig. 6A As shown, the reinforcement means 11 may be in the form of a plate 11a, arranged along the longitudinal direction of the radiating element 1. Furthermore, it can be seen from this exemplary figure that, viewed from the radiating element 1 installed in use, the reinforcement means 11a in the form of a plate is positioned at at least one connection seat 6, preferably in a low or lower position.

[0151] The number, length and arrangement of the reinforcing means 11a may vary according to the needs of the reinforcement itself.

[0152] Of course, the means 11a may allow fluid communication within the cavity 4 and, therefore, may be provided with slots or other openings to allow the passage of air or other gas contained within the radiant element 1 so as to ensure uniformity of heat transfer.

[0153] In at least one version of the invention, the reinforcement means 11 comprise pins and / or studs and a plate 11 a.

[0154] In fact, the weight of at least one device 10, for example the weight of a corresponding resistor or a fuel burner, may constitute a problem for the radiating element 1 according to the invention, since the material used for the radiating element itself may lose its ability to support the weight at high temperatures. Therefore, the radiating element 1 may experience deformations and / or damages if it is required to support too much weight.

[0155] According to at least one version of the invention, due to the high temperature and / or weight of the heating device 10, the zone most susceptible to deformation is located at the bottom (seen from the radiating element 1 mounted in use) and / or at the first end 8a.

[0156] According to one version of the invention, the device 10, for example a resistor, comprises a plurality of longitudinal cables or plates 10a (placed adjacent to each other) through which an electric current passes (for example Figure 5A and 5B As shown). A plurality of such cables or plates are held in place and supported by at least one disc or at least one plate 10b. The disc or plate 10b has at least one hole at its central section for the passage of the cable 10a ( Figure 5A ), the wires 10a (also applies to the electrical boards) must not touch each other and / or must not touch materials placed near them, such as the inner surface of the radiating element 1 (to reduce the risk of short circuits).

[0157] Thus, the disk or plate 10b has an outer section 10c, if necessary in the shape of an annulus, shielding the electrical cable or plate 10a from the surroundings. According to at least one version of the invention, the disk or plate 10b and / or its outer section 10c rests on the inner surface 3a of the radiating element, which is situated at at least one main hollow seat 5. Thus, in fact, it rests on the inner surface 3a at the portions 5a, 5b of at least one main hollow seat 5.

[0158] The disc or plate 10b is made of a refractory material, such as a ceramic material or the like.

[0159] On the other hand, in this version, the heating means 10 comprise fuel burners, which consist of plates or plates or other suitable means, which plates or plates have, if necessary, external sections which can rest on the inner surface 3a at the portion 5a, 5b of at least one main hollow seat 5 or in another suitable seat of the radiant element 1 or at least one wall of the furnace. Alternatively, the heating means 10 in the form of fuel burners can be fixed at at least one lateral end 8 of the radiant element so as to be fixed in place without contacting the inner surface 3a.

[0160] Thus, at least one reinforcing means 11, 11a supports and distributes the weight of the device 10 at the necessary point, for example along the longitudinal extension L of the element itself. In particular, in fact, according to at least one version of the invention, at least one device 10 is not in contact with at least one reinforcing means 11, 11a. In fact, the latter are placed in series, for example, along the extension of at least one connection seat 6, keeping the distance between the sections 6a, 6b fixed, preventing the radiating element from opening at least in some of its parts or increasing its thickness W, thus causing displacement of at least one device 10 contained therein.

[0161] In this way, due to the presence of at least one reinforcing means 11 , 11 a , breakage of the disk or plate 10 b of the device 10 is reduced, deformation of the radiating element 1 is reduced, and slippage of the disk or plate 10 b relative to the radiating element 1 itself is reduced.

[0162] What we mean by "sliding" is the expansion movement, such as elongation, caused by the high operating temperature experienced by the material during processing (because parts made of different materials also have different elongations at high temperatures).

[0163] Of course, ensuring the default values ​​for the components involved are low, thermal efficiency is ensured over time.

[0164] The at least one reinforcement means 11, 11a may be a separate element at the inner surface 3a of the radiating element, or it may be part of the radiating element 1 itself, in the sense that it may be obtained by bending and special configuration of the metal sheet from which it is manufactured.

[0165] Of course, the number and arrangement of electrical cables or the number and cross-section of electrical plates (which may have a circular cross-section or present any shape and form) or the shape and size of the fuel burner will change the shape and size of the disc or plate 10b, and thereby also the shape and size of at least one reinforcement device 11, 11a.

[0166] When the device 10 is driven electrically, the at least one heating device can have different shapes and configurations, and the radiating element or the at least two main hollow seats 5 will be adapted to them, and vice versa.

[0167] Current supply cables may extend from the at least one heating device 10. For example, these cables are guided towards the second end 8b of the radiating element 1. The latter therefore only requires a region for the entry and / or exit of the supply cables of the at least one device 10 (for example at the second end 8b).

[0168] In particular, these cables are placed at the mat 12 and / or end outside the mat 12. The same applies when the at least one heating device 10 is in the form of a fuel burner.

[0169] If necessary, the device 10 with the inner end substantially reaches a few centimeters of the closing plate 15 situated at the first end 8a of the radiating element 1 .

[0170] As mentioned above, each main hollow seat 5 can accommodate one, two, three, four, five, six or more devices 10 inside it, depending on its size and the power required for heating.

[0171] The radiating element 1 also comprises, at the second end 8b (or outlet end), the aforementioned housing element 12. The housing element 12 is located at the rear relative to the radiating element 1. It consists of a box-shaped element, preferably made of metal, which is called a "pad" in the jargon. It is resistant to high temperatures and has a protection system for the outside and / or external area. This protection system may comprise optical fibers inside, a covering or cladding, for example in the shape of a stainless steel plate, towards the inner wall of the furnace and iron towards the outer wall of the furnace itself. If necessary, such a protection system may comprise a material consisting of or based on biofibers and / or ceramic materials, capable of avoiding the transfer of heat outside the radiating element 1 and / or the furnace in which it is installed.

[0172] Thus, the containing element 12 is placed outside the furnace and the radiating elements are placed thereon, for example at their second ends 8b.

[0173] If necessary, the containment element 12 and / or the protection system may also include a covering element made of sheet metal, for example covering the cables of the device 10, in order to protect the operators of the furnace from short circuits or accidental damage.

[0174] Therefore, the pad is thermally insulating.

[0175] Furthermore, the positioning of the at least one device 10 relative to the mat also serves to protect the safety of the operators working on site. In fact, the at least one device 10 reaches a very low temperature in its initial section (the second end 8b facing the radiation element), ensuring that the heat emission towards the outside of the furnace (the operator's working area) is less than 85°C.

[0176] This is of course not possible for conventional radiant tube systems, and the external temperature parameters are also subject to strict standards. Due to the above-mentioned concept, the present invention also seeks to meet these requirements.

[0177] Sealing on the outside of the furnace and heating system can be achieved by means of one or more series of flanges or a single flange 13, for example, the shape of which is based on the number of devices 10 to be inserted. The at least one flange is located on the rear side of the radiant element 1, namely at its second end 8b.

[0178] Each device 10 may be provided with a flange 13, or some or all of the devices 10 may be provided with a flange 13. According to at least one version of the invention, at least one flange 13 is placed only at the pad 12 and / or at the second end 8b and / or may be used to fix the respective device 10, for example by screws and bolts.

[0179] In this way, the replacement time of the resistor and / or of at least one device 10 is reduced and greater safety is achieved for the operating personnel when such at least one device 10 needs to be replaced.

[0180] Furthermore, in at least one version of the invention, at least one flange 13 may comprise at least one external compensator. The at least one external compensator has any requested function of allowing the radiant elements 1 to expand also towards the outside of the furnace itself (they may expand about + / - 5 cm).

[0181] According to at least one version of the invention, the shape of the radiating element 1 can be different when viewed from the inner surface 3a and from the outer surface 3b. This is because the radiating element 1 can include reinforcement and / or strengthening means such as longitudinal, transverse and / or horizontal corrugations, studs of any shape and size, ribs, grooves or others.

[0182] These reinforcement and / or stiffening means may be positioned and / or made at the inner surface 3 a and / or the outer surface 3 b of the radiating element 1 .

[0183] These reinforcement and / or stiffening means may be obtained directly from the shaping of the metal sheet constituting the radiating element 1 , for example by calendaring or pressing using suitable dies, or by the successive application of welding or other known fixing systems.

[0184] These strengthening and / or reinforcement means may serve to strengthen the material of the radiating element 1 and, therefore, ensure a longer lifetime thereof.

[0185] Figure 6B and Figure 7B Two examples of reinforcement and / or strengthening means are shown, namely reinforcement and / or strengthening means 14 of external type, which only cover a part of the outer surface of the radiating element 1 ( Figure 6B, in particular, in use, it is placed at three or four main hollow seats 5 starting from the bottom, thus having a U-shape starting from the bottom and at least partially surrounding the front and back surfaces of the radiating element 1) or the entire outer surface of the radiating element ( Figure 7B , wherein the reinforcing and / or strengthening means 14 surrounds the entire periphery of the radiating element, whether on the front or on the back side of the radiating element 1, as viewed from its lateral extension M). The reinforcing and / or strengthening means 14 can be made of a high temperature resistant material, for example chosen from the possible materials of the radiating element 1, for example a material with or without high alloy or low alloy or high alloy or alloyed with nickel, molybdenum or cobalt, for example Inconel 600 / 601 / 602, Avesta, Alloy 800H, AISI 309 / 310 / 316 / 321, Kanthal APM / APM-T, A1, or at least one material obtained by melting / casting, forging, extrusion or other or any other material that can be used for this purpose. For example, Inconel 600 / 601 / 602, Avesta, Alloy 800H, AISI309 / 310 / 316 / 321, Kanthal APM / APM-T, A1, or at least one material obtained by melting / casting, forging, extrusion or other or any other material that can be used for this purpose.

[0186] The reinforcing and / or strengthening means 14 can have a length equal to the main longitudinal extension L of the radiating element 1, or they can be placed only on a part of the same radiating element 1, for example in a central position and / or at its ends 8a, 8b (preferably 8a), or still in points of the radiating element 1, wherein several yields related to the temperature and / or weight of at least one means 10 comprised by the radiating element may occur.

[0187] The purpose of the reinforcing and / or strengthening means 14 is to strengthen the structure of the radiating element 1, for example at at least one of its ends 8, in order to reduce or avoid any type of twisting or deformation of the entire structure or of its parts. In at least one version of the invention, the means 14 are positioned at the outer surface 3b of the wall 2 of the radiating element 1.

[0188] Wherein, in this version, the radiating element 1 is positioned in the furnace by means of a horizontal arrangement (considering that, unless expressly contrary, the above-mentioned position generally refers to the positioning of the radiating element in the furnace by means of a vertical arrangement or by means of both vertical and horizontal arrangements), the reinforcing and / or stiffening means and / or at least one stiffening means 11, 11a are positioned on the upper surface (or facing the ceiling) and / or the rear surface (or facing the floor) of the radiating element 1 in use. In this case, the reinforcing and / or stiffening means and / or at least one stiffening means 11, 11a may be in the form of plates, ribs or longitudinal grooves, corrugations, bosses, protrusions and / or fixings, etc., protruding internally and / or externally, for example, placed at the outer and / or inner surface of at least one main seat 5, and / or facing upwards and / or downwards, constituting the shape of an element radiating element or an element welded thereto, having, viewed in its longitudinal extension, a length corresponding to the length of the radiating element, or being segmented with a constant or irregular pitch according to specific areas that need to be more reinforced and / or stiffened.

[0189] The radiating element 1 may be formed and / or shaped by pressing a metal sheet, rolling at least a portion of the radiating element 1 and / or may be obtained by melting, centrifuging at least one metal constituting it, forging and / or modeling or the like.

[0190] Due to the specific shape and / or the manufacturing method of the radiating element according to the invention, it has very few cuts in the material constituting it and therefore also a small number of parts welded together.

[0191] For example, consider a conventional type of radiant tube, for example of the W type, composed, for example, of four longitudinally welded straight tubes, three curved tubular sections molded from two halves by internal and external welding, four or more circumferential welds for connecting the various elements. On the other hand, the radiant element according to at least one version of the invention may comprise a single longitudinal weld, for example joining two longitudinal edges of a sheet material cut to a suitable size and shape so as to join the wall 2 and determine the formation of the internal cavity 4.

[0192] In at least one version of the invention, the radiant element 1 according to the invention may consist of at least one shaped sheet (to form the parts 5a, 5b and the segments 6a, 6b) or of two or more shaped sheets, depending on the shape of the radiant element 1 and / or the type of furnace (longitudinal, vertical, etc.) in which it is to be installed (for example in the case of installation in an existing furnace).

[0193] Therefore, in at least one version of the invention, the wall 2 of the radiating element 1 consists of and / or forms at least one shell or two or more half-shells, which are mounted in the same housing element 12 (pad).

[0194] When the connection seats 6 are hollow inside, they constitute a kind of empty space inside the inner cavity 4. This allows heat to be transferred between one device 10 and another and between one main hollow seat and another. In this way, the temperature is uniform along the entire surface of the radiating element 1, which also ensures uniform expansion and dilation of the material, reducing stress and fatigue on the radiating element, significantly extending its life.

[0195] Furthermore, the presence of the connection seat 6 has the function of supporting the device 10 and allowing it to expand due to temperature rise. In fact, as mentioned above, the thickness W1 of the connection seat 6 is less than the thickness W2 of the main hollow seat 5, forming a kind of narrowing in the cavity 4, on which the disk or plate of the electric or fuel-driven heating device 10 and / or at least one reinforcement device 11, 11a rests.

[0196] The width of the sections 6a, 6b (viewed in the transverse direction of the radiating element 1) may be a few centimeters or between 1 cm and 5 cm or between 1 cm and 25 cm.

[0197] As mentioned above, in any case the entire wall 2 of the radiant element 1 is heated, including the portions 6a, 6b, thereby ensuring temperature uniformity and increased thermal efficiency of heat transfer.

[0198] It can be seen from this how the present invention achieves the intended purpose.

[0199] In fact, the radiant element 1 according to the invention has a uniform temperature along its entire extension and has a mass or radiant surface increased by more than 65% compared to radiant tubes currently on the market, for example.

[0200] For example, the total surface area of ​​a W-shaped radiant tube is 5.6m 2 , the maximum exchange surface area is 3.7m 2 , while the total surface area of ​​the radiating element 1 according to the invention is 7.7 m 2 , the exchange surface area is at least 6.1m 2 (For the same length, considering the same furnace.) Obviously, these values ​​will vary from furnace to furnace, since each furnace has a different distance between the furnace walls, but the surface advantage is proportional to the distance between the walls (i.e., the distance between the furnace walls).

[0201] This allows for the following advantages:

[0202] A. Reduction of consumption: for example, the average / maximum efficiency of a gas burner is 75-80%, while the average / maximum efficiency of a heating device, for example with power supply 10, is 90-100%. Therefore, if you want to replace a burner with a power of 150Kw, a resistor with a power of 110 / 120Kw is sufficient to obtain the same heating effect (of course the power can be higher, even up to 200Kw and above, depending on the needs);

[0203] B. Management of the radiation elements: their use can be adjusted according to the actual thermal treatment needs of the strip, since the radiation quality (or surface) and at least one heating device 10 can meet all needs with high performance;

[0204] C. Improvement of the quality of the heat treatment and thus of the tape that passes through it: this is due to the uniformity of the radiation and heat emission obtained by the radiating element according to the invention, and it makes it possible to increase and improve the technical and mechanical characteristics of the tape, for more extreme uses in the industries in which it will be applied (for example, in the automotive and / or aerospace fields, to improve the impact resistance, obtaining materials able to withstand increasingly strong shocks and stresses, with increasingly higher resistance to creep.) Therefore, the material treated by the radiating element according to the invention will be better, more reliable, durable and more resistant from the point of view of physical-mechanical properties;

[0205] D. Ease of use: This is achieved, for example, according to a version of the invention, as opposed to combustion systems that require continuous maintenance and replacement of burner parts, such as heads, nozzles, regenerators, and consumable parts;

[0206] E. Computerization and standardization of the system: By designing the radiant elements in this way, both in terms of construction and in terms of radiant quality / surface and internal heating elements, it is possible, through a dedicated software system, to differentiate the heating zones as required, while maintaining the required temperature uniformity and significantly reducing the current or fuel required to heat the radiant elements themselves, thus inputting the energy required for the radiation of the heating elements. For example, when there are several devices 10, such as six resistors or six fuel burners, it is possible to make them work intermittently or as required, for example by activating resistors 1, 3 and 5, keeping resistors 2, 4 and 6 off, or reducing their power, in order to then repeat the same working operation in reverse, i.e. increasing the power of resistors 2, 4 and 6 and reducing the power of the other resistors 1, 3 and 5. The same effect can also be obtained using heating devices 10 of the fuel burner type;

[0207] F. Energy efficiency and reduction / zero harmful emissions: According to a particular embodiment of the invention, in addition to the emissions related to the radiant element itself, it also includes the level of production of electrical energy required for its operation. In fact, as mentioned before, reducing consumption can save electricity or fuel and thus reduce the CO2 emitted into the atmosphere by production plants (power plants, nuclear power plants and any other form of energy production);

[0208] G. Lower power required for the heating device 10, for example electrically driven heating devices: Due to the above advantages and the possibility of using several resistors (3 or 6 or 9 or 12 or more, depending on the size of the radiant element and the needs of the heat treatment), each device 10 and / or each internal resistor requires a power of 10Kw or 17Kw to 30Kw, up to 50Kw or more if necessary. This also determines a reduction in power consumption, greater control possibilities and the possibility of choosing the size and shape of the resistors themselves, also allowing the radiant elements to reduce their dimensions compared to traditional radiant tubes and finally making it possible to study new furnaces with dimensions smaller than the current ones;

[0209] H. Reduction of stress exerted on the heating devices: it is possible to shut down or reduce the power of certain devices 10 and / or certain resistors or burners, which no longer need to operate continuously at 100% power, preserving the physical decay of the materials from which they are made, reducing the need to replace them and thus also reducing costs for the user. In addition, the reduction of the necessary energy has benefits for all connected components, such as the substation, which transforms the current to feed the resistors in the system, the current channel cables, which are less stressed and have smaller dimensions, and finally, overall savings in the management of the entire system;

[0210] I. Reduced risk of explosion and leakage: due to lower power required and reduced stress;

[0211] J. Possibility of using renewable energy or energy obtained from renewable sources: For electricity production, in addition to current power plants, it is possible to use photovoltaic, wind, nuclear, etc. The same goes for fuel, which can come from renewable sources, also taking into account CO2 emissions, etc.

[0212] It can thus be seen that the above-mentioned advantages cannot be achieved with the solutions known from the prior art.

[0213] The characteristic of the radiant element according to the invention is that it distributes the energy emitted by the heating device 10 (that is to say by the resistor or burner according to at least one version of the invention) over a surface (such as the wall 2) that is much wider than a standard tube, for example formed by a single tube with a circular cross section.

[0214] According to the version of the heating device 10 driven by electricity, in terms of mechanical characteristics, taking into account the material of the radiating element itself, the resistance is preferably not more than 2.2-2.5 W / cm 2and / or not more than 3.0-3.5W / cm 2 The high powers required for energy transfer, i.e. heat transfer from the radiating element to the metal strip or other material for heat treatment, require greater powers and / or increasingly larger resistors (from the classic 20Kw to 40Kw or even 60Kw). Neither resistors nor conventional tubes with reduced surface area, such as single tubes of circular cross-section, can tolerate such powers in terms of mechanical properties and fatigue resistance.

[0215] On the other hand, the radiant element according to the invention, in at least one particular version, has a radiant surface increased by more than 70% with respect to a standard solution (also considering a tube with a diameter of 200 mm on the same mat), thanks to mechanically "receiving and supporting" the power supplied by the heating device 10 and exchanging it without stressing the base material of the radiant element itself. Moreover, in addition to the improved result, the production costs are extremely competitive and lower than, for example, the tubes sold by Kanthal (whose thickness can reach 9 mm for materials composed of iron, chromium and aluminum alloys, which, however, have a lower heat exchange efficiency, at least above a certain threshold, in the context of the invention).

[0216] Furthermore, at least according to one version of the invention, the radiant element can be defined as a housing containing a plurality of heating means 10, such as electrical resistances or fuel burners, instead of a single one, such as a single radiant tube of known type, taking into account the entire system.

[0217] Finally, the radiant element according to the invention is capable of exchanging a power generated by the heating device 10 equal to about 120 Kw or up to 240 Kw (taking into account the above W / cm 2 parameters).

[0218] Each radiating element requires this power and, thanks to the invention, the mechanical and fatigue stresses exerted on the radiating element material can be significantly reduced, so that not only the heat can be actively and effectively transferred to the strip or material to be treated, but also the life of the radiating element itself can be extended (for example, compared to a metal sheet tube of circular cross-section).

[0219] The invention also relates to a radiation system consisting of a radiation element 1 and / or a plurality of radiation elements 1 and a corresponding number of heating devices 10 and to the use thereof in a heat treatment.

[0220] Features described for one version or embodiment or configuration of a component of the invention may also be present in other variations or embodiments of one or more components of the invention without departing from the scope of protection provided by the appended claims.

Claims

1. A radiant element (1) for use in at least one furnace for heat treatment and / or in a continuous galvanizing and annealing line for metal sheets, strips or plates and / or other products made of steel and / or other metals and / or for the modernization of at least one pre-existing furnace, wherein: The radiation element (1) is used to emit and / or radiate heat, wherein the radiation element (1) has a main longitudinal extension (L) and a transverse extension (M) perpendicular to the main longitudinal extension (L), wherein the radiation element (3) comprises a shaped wall (2) defining an outer surface (3b), an inner surface (3a) and an inner cavity (4), wherein the inner surface (3a) faces the inner cavity (4) and the outer surface (3b) is opposite to the inner surface (3a), characterized in that the cavity (4) comprises at least two main hollow seats (5) suitable for accommodating at least one heating device (10) during use, and the radiation element (1) also comprises at least one connecting seat (6) of the at least two main hollow seats (5).

2. The radiation element (1) according to claim 1, characterized in that Each of the at least two main hollow seats (5) and the at least one connecting seat (6) has a main longitudinal extension parallel to each other and parallel to the main longitudinal extension (L) of the radiating element (1).

3. The radiation element (1) according to claim 1 or 2, characterized in that It comprises n main hollow seats (5) and n-1 connecting seats (6), wherein n is greater than 2, or wherein, The radiation element (1) comprises three main hollow seats (5) and two connecting seats (6), or six main hollow seats (5) and five connecting seats.

4. The radiating element (1) according to any one of the preceding claims, characterized in that The at least one main hollow seat (5) has a cross-section of a circular or polygonal shape, such as a square, rectangular, prismatic, hexagonal, octagonal, etc., and / or a substantially cylindrical or parallelepiped shape, and / or wherein, The at least one connection seat (6) has a substantially polygonal, for example rectangular or square, cross section and / or a parallelepiped shape with a polygonal, rectangular or square base.

5. Radiating element (1) according to any one of the preceding claims, characterized in that The cavity (4) is formed by the at least two main hollow seats (5) and the at least one connecting seat (6), so the cavity (4) is hollow.

6. Radiating element (1) according to the preceding claim, characterized in that Between the at least one main hollow seat (5) and the at least one connecting seat (6), there is at least one port or opening (7) inside for fluid passage and / or connection between the at least two main hollow seats (5) and the at least one connecting seat (6).

7. Radiating element (1) according to any one of the preceding claims, characterized in that The wall (2) is continuous and, at least with respect to the main longitudinal extension (L) and the transverse extension (M), is free of openings capable of placing the inner cavity (4) in communication with the outside.

8. Radiating element (1) according to any one of the preceding claims, characterized in that The wall (2) is composed of at least two sections (6a, 6b) defining the at least one connecting seat (6) and at least one portion (5a, 5b) defining each of the two main hollow seats (5).

9. Radiating element (1) according to the preceding claim, characterized in that The at least two sections (6a, 6b) are substantially flat or curved, and wherein, when the at least two main hollow seats (5) are placed outside and at opposite longitudinal ends of the radiating element (1), at least one portion (5a, 5b) has a recess facing the interior of the radiating unit (1).

10. The radiating element (1) according to any one of the preceding claims, characterized in that Comprising two transverse ends (8), said transverse ends (8) being placed on opposite sides of said main longitudinal extension (L), wherein said two transverse ends (8) comprise a first end (8a) and a second end (8b), said first end (8a) being suitable in use for connection and / or positioning at a first wall of said furnace, for example, a furnace equipped with a "furnace side support" or "socket" (20), and said second end (8b) being suitable in use for connection and / or positioning at a second wall of said furnace, said second wall being opposite to said first wall, wherein said radiating element (1) comprises a support (9) for said radiating element (1) placed at said first end (8a) and a receiving element or pad (12) placed at said second end (8b).

11. The radiating element (1) according to any one of the preceding claims, characterized in that The radiation element comprises the at least one electrically or fuel-driven heating device (10) and is capable of heating the radiation unit (1), wherein the at least one heating device (10) is housed in at least one or each of the at least two main hollow seats (5).

12. The radiation element (1) according to claim 11, characterized in that The at least one electrically driven heating device (10) comprises at least one resistor or electric resistor and / or comprises a plurality of electric longitudinal cables or electric plates (10a) through which electric current passes, Therein, the plurality of electrical longitudinal cables or electrical plates (10a) are held in place and supported by at least one disc or at least one plate (10b) made of refractory material, such as ceramic material or the like.

13. The radiation element (1) according to claim 11, characterized in that The at least one fuel-driven heating device (10) comprises at least one burner driven by the fuel, such as gas, hydrogen, methane, biofuel, zero-emission fuel, e-fuel, "carbon-neutral" synthetic fuel, etc.

14. Radiating element (1) according to any one of the preceding claims, characterized in that It comprises at least one reinforcing means (11, 11a) for supporting and / or maintaining the radiating element (1) in position, preferably positioned in the main hollow seat (5) and / or in the at least one connecting seat (6).

15. Radiating element (1) according to the preceding claim, characterized in that The reinforcing means (11) comprises at least one plate (11a), screw, bolt, rod, pin, peg or other similar reinforcing element, and / or has a cylindrical, conical, flat, parallelepiped, prismatic or other shape, and / or wherein: The at least one reinforcement device (11, 11a) is fixed, welded or force-fitted at the inner surface (3a), and / or the outer surface (3b) and / or the at least one section (6a, 6b) and / or the portion (5a, 5b).

16. Radiating element (1) according to any one of the preceding claims, characterized in that The cavity (4), the at least one main hollow seat (5) and the at least one connecting seat (6) extend along the entire main longitudinal extension (L) of the radiating element (1).

17. Radiating element (1) according to any one of the preceding claims, characterized in that It comprises a formed flange (13) located at the second lateral end (8b) of the radiating element (1), at least one compensator, reinforcing means and / or reinforcing elements (14), such as longitudinal, lateral and / or horizontal undulations, bosses, ribs, grooves, etc., and a U-shaped element positioned or made at the inner surface (3a) and / or with the outer surface (3b).

18. Radiation system for at least one heat treatment furnace and / or for a continuous galvanizing and annealing line for metal sheets, strips or plates and / or other products made of steel and / or other metals and / or for the modernization of at least one existing furnace, comprising at least one radiation element (1) according to any one of claims 1 to 17 and at least one heating device (10) or at least two heating devices (10) for heating the at least one radiation element (1) to 1200° C. or above and allowing the radiation element (1) to emit and / or radiate heat during use.

19. Use of a radiation system according to claim 18 for heat treatment of sheet metal strips or plates or other products made of steel and / or other metals in a heat treatment furnace and / or for continuous galvanizing and annealing lines and / or for modernization of pre-existing furnaces, wherein The at least one radiation element (1) emits and / or radiates heat towards the sheet metal strip or plate and / or other product made of steel and / or other metal in order to determine a heat treatment for it.

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