Radiant elements powered by heating means and uses thereof - Patent Application 20070122997

Abstract

A radiant element (1) usable in at least one furnace for heat treatment and / or for continuous galvanizing and annealing lines for sheet metal strip or plate and / or other products made of steel and / or other metals, and / or for the modernization of at least one existing furnace, said radiant element (1) being used to emit and / or radiate heat, said radiant element (1) having a main longitudinal extension (L) and a transverse extension (M) perpendicular to said main longitudinal extension (L), and comprising a forming wall (2) defining an outer surface (3b), an inner surface (3a), and an internal cavity (4), as well as at least two main hollow seats (5) adapted to accommodate at least one heating means (10) and at least one connecting seat (6) in use, and a radiant system and use of this radiant element (1).

Description

[Technical Field]

[0001] The present invention relates to a radiant element powered electrically or generally by heating means, for industrial plants and the like, which can be used in the section of furnaces or plants for the heat treatment of steel and / or other metals.

[0002] More specifically, the invention relates to a radiant element powered and / or heated electrically or generally by a heating means, which radiant element can be used in furnaces for heat treatment generally, and / or continuous galvanizing and continuous annealing lines (such as CGL, AGL, CAPL or CAL lines) of strips or panels, bolts, wire rods, pipes, parts for pipes and fittings made of sheet metal, for the processing and production of "Advanced High Strength Steels" (AHSS) and new steel grades, and / or other products made of steel and / or 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 in continuous galvanizing and continuous annealing lines, and generally in any furnace for heat treatment.

[0004] The present invention therefore finds application both in the automotive sector and in the steel and / or aluminium sector, etc. [Background technology]

[0005] The increasingly disruptive climate change, which consequently requires the reduction of NOx and CO2 emissions into the atmosphere, has forced industry in general and steelmakers in particular to implement a series of substantial actions worldwide to achieve this goal in a short space of time.

[0006] As is known, most ferrous or aluminum alloys and other materials suitable for the manufacture of parts necessary for daily life are subjected to heat treatment in order to obtain better durability, higher hardness and / or better performance over time during their functional cycle.

[0007] In this sense, the steel / automotive sector generally uses furnaces used to perform heat treatments at high temperatures (from 200°C to over 1200°C) on materials that are then sold and used in many types of industries.

[0008] Today, for example, the heat treatment of sheet metal and its derivatives is carried out to a large extent by means of heat obtained from radiant tubes of any shape (W or M, U, double and single P, I, L or any other geometric shape), so that the sheet metal passing near them in the form of a continuous band can undergo the desired heat treatment.

[0009] The materials used to make these radiant tubes are characterized by high resistance to temperatures up to 1200°C and above (in the case of radiant tubes made of ceramic materials, heat resistance up to 1500°C can be obtained).

[0010] These tubes are usually connected to gas burners (although other fuels such as hydrogen, methane etc. are also used) that generate the temperature and power required for their operation and the processes carried out.

[0011] These systems require a flame inlet area (burner side), a smoke passage area (to heat the radiant tube), and a smoke outlet area with a recovery unit (to reduce the very high emissions inside the tube itself and to allow recirculation of some of the fumes so that they can be reburned and thus ultimately reduce emissions).

[0012] These burners emit a very hot flame (up to 1300°C and above) inside the radiant tube, which heats by radiation (hence the name radiant tube) the strip, e.g. metal sheet, passing through the interior of the furnace until it reaches the required treatment 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 produce very high levels of emissions into the atmosphere, particularly NOx and CO2.

[0014] For example, the European Community has set the emission range per line (furnace) at 100 mg / m 3 ~300mg / m 3 While individual European states can determine the minimum and maximum values ​​allowed, Europe, the United States and all other parts of the world have limits that significantly exceed the aforementioned values, even exceeding 350 mg / m 3 ~500mg / m 3 There are many plants that reach levels above this.

[0015] Much effort has been made to be able to reduce these emission levels, and the efforts made by all companies in the sector have been very important, but the systems themselves (burners, gases, fume recirculation systems inside the pipes, radiation, recuperation, etc.) make it increasingly difficult to obtain satisfactory long-term results.

[0016] In fact, one of the problems of a flame burner is precisely maintaining the combustion parameters over time so that there are constant and controlled emissions. Any "disturbance" (loss) of the operating parameters (regulation) would otherwise entail continuous maintenance and control demands, and in most cases would lead to a quick return to base conditions and an increase in the emission parameters over time (to values ​​that are excessive in light of current regulations).

[0017] This type of inconvenience requires steelmakers to invest large amounts of money in controlling and continually adjusting (tuning) the burners and combustion systems. Furthermore, this loss of the basic parameters for optimal combustion often results in greater aggressiveness of the burner flame, leading to serious lifespan problems for the radiant tube, with deformation of the hottest part (generally the burner side), cracks in the material itself and in the welds, and a continuous need for spare parts and line shutdowns (furnaces) to replace damaged parts.

[0018] Some furnaces have multiple electric heating elements, which preferably operate at high kilowatt values ​​to keep both the number and size of the heating elements, as well as the size of the furnace itself, to a minimum. Typically, the heating elements operate inside a tubular vessel, protecting them from the gases present inside the furnace.

[0019] However, these heating elements must operate at high power and high watt densities (calculated as watts per square centimeter of the surface area of ​​the conductive element) to provide the furnace with the power required for the work being done within it, which creates a high risk of short circuits or system failure.

[0020] Increasing the number of heating elements does not solve the problem, since this requires increasing the size of the furnace, resulting in increased losses and associated operating costs, not to mention the fact that existing furnaces are often not equipped to support such an increase.

[0021] Patent Document 1 discloses a heating assembly for use inside a radiator for an electric furnace. The heating element of the heating assembly is shaped like a molded rod and attached to a ceramic insulating disk that supports the rod element itself. There may be a single tube cover to protect the heating element.

[0022] US Patent No. 5,929,999 discloses a single tube heating element for a furnace that includes a wire resistor, the resistor including multiple wires connected in parallel to provide high wattage while maintaining watt density below a safety threshold. It can therefore be seen that there is a strong need to provide a radiant element that is powered electrically, or in general by a heating means, which is able to overcome the drawbacks of the prior art mentioned above. [Prior art documents] [Patent documents]

[0023] [Patent Document 1] U.S. Patent No. 5,473,141 [Patent Document 2] U.S. Patent No. 5,083,012 Summary of the Invention [Problem to be solved by the invention]

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

[0025] Within this technical objective, the object of the present invention is to provide a radiant element that makes it possible to reduce or eliminate emissions, such as NOx and CO2, caused by heat treatment lines in any sector, from automotive to steel, aluminum, etc.

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

[0027] Yet another object of one aspect of the present invention is to provide radiant elements in the heat treatment sector that no longer require burners powered by any fuel, but are powered in an alternative way, for example electrically, for example by motorized means / using electric induction.

[0028] A further object of the present invention is to provide a radiant element that can ensure improved thermal efficiency and uniform temperature (by increasing it if desired) along the entire surface of the radiant element itself.

[0029] Yet another object of the present invention is to provide a radiant element that can last longer than conventional radiant tubes and has a longer lifespan, since by ensuring uniformity of temperature along its entire length, it may undergo the same expansion and recoil movements in the temperature changes required for heat treatment of the material, effectively reducing stresses and cracks or tears that may be experienced by the material that makes up the radiant element itself. [Means for solving the problem]

[0030] This aim and object is achieved by a radiating element as claimed in claim 1 attached hereto.

[0031] Further advantageous features are set forth in the dependent claims. [Brief explanation of the drawings]

[0032] The features of the present invention will be better understood by those skilled in the art from the following description and the accompanying tables of drawings, given as non-limiting examples. [Figure 1] FIG. 2 is a side view of one embodiment of a radiating element according to the present invention. [Figure 2] FIG. 2 is a rear view of the radiating element of FIG. 1. [Figure 3] 1 is a perspective view of one embodiment of a radiating element according to the present invention; [Figure 4A] FIG. 10 is a side view of another embodiment of a radiating element according to the present invention. [Figure 4B] FIG. 4B is a cross-sectional view taken along the plane of trace CC in FIG. 4A. [Figure 4C] FIG. 4B is a front view of a portion of the radiating element of FIG. 4A, where the support for the radiating element itself can be seen. [Figure 4D] FIG. 4B is a rear view of the radiating element of FIG. 4A. [Figure 5A] FIG. 1 illustrates a resistor or electrical resistance having electrical wires and electrical plates. [Figure 5B] FIG. 1 illustrates a resistor or electrical resistance having electrical wires and electrical plates. [Figure 6A] FIG. 2 is a side view of one embodiment of a radiating element according to the present invention. [Figure 6B] FIG. 6B is a cross-sectional view taken along the plane of trace DD in FIG. 6A. [Figure 7A] FIG. 2 is a side view of one embodiment of a radiating element according to the present invention. [Figure 7B] FIG. 7B is a cross-sectional view taken along the plane of trace DD in FIG. 7A. [Figure 8A] 10 is a perspective view of a further embodiment of a radiating element according to the present invention; FIG. [Figure 8B] 10 is a perspective view of a further embodiment of a radiating element according to the present invention; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0033] With reference to the attached drawing, 1 denotes a radiant element, which can be used in furnaces for the heat treatment and / or in continuous galvanizing and annealing lines for sheet metal strips and plates and / or other products made of steel and / or other metals (in particular CGL, AGL, CAPL, CAL lines, etc.) and / or can also be used to retrofit existing furnaces.

[0034] The present invention also relates to a complete radiant system, and therefore to a radiant and heating system of which the radiant element 1 is part, together with at least one heating means 10, such as for example at least one electrically or fuel-powered heating means.

[0035] At least one heating means, for example electrically or fuel powered, is a heating means for the radiant element 1. In practice, it heats the radiant element, for example to a temperature of more than 1200°C, allowing the radiant element to emit / radiate heat outwards (for example towards the sheet metal strip passing nearby for the desired heat treatment) to carry out the heat treatment itself.

[0036] In its electrically driven embodiment, the at least one heating means 10 comprises or is in the form of at least one electrical resistance (eg also called a resistor).

[0037] The at least one electrically-powered heating means 10 may be electrically inductive or may have at least one electrical induction.

[0038] In an alternative embodiment, the heating means 10 is fuel powered, i.e. a burner powered by, for example, gas, hydrogen, methane, biofuel, zero emission fuel, e-fuel, carbon neutral synthetic fuel, or the like.

[0039] In at least one embodiment of the invention, the radiant element comprises and houses at least one heating means 10, as specified in more detail below.

[0040] The use of electrical resistance is common, for example, for heating domestic or working environments (offices and large sheds). However, in this case, the power used, and above all the temperature to be achieved, is very low, since the aim is to heat a room for normal daily life.

[0041] However, in the field of processing common materials (steel, aluminum, copper, etc.), as mentioned above, very high powers and especially very high temperatures (up to 1200° C. and above, if necessary) are required.

[0042] Therefore, the at least one heating means according to the invention must be able to ensure the achievement of the power and temperature required for the operation outlined above.

[0043] Electrical resistors, due to their weight, their structure and the materials from which they are made, exhibit a thermal expansion that is different from the thermal expansion that occurs for the material from which the radiating element 1 is made or the material from which the radiating element 1 is made.

[0044] In fact, the radiating element according to the invention can be obtained from a metal sheet with or without high or low nickel, molybdenum or cobalt alloys, such as, for example, 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 fusion / casting, forging, extrusion or any other material available for that purpose.

[0045] The radiating element according to the invention has a completely innovative shape and design.

[0046] This is also related to the fact that, in at least one of its embodiments, it is free and independent of the burner for its heating, so that it no longer requires one or more inlet zones for the fumes and / or flames coming from the burner, nor one or more fume outlet zones. Despite this, the radiant element according to the invention is an element that can determine the thermal radiation / irradiation and obtain all the necessary advantages in terms of energy efficiency, heat transfer and the reduction or elimination of harmful emissions, in particular NOx and CO2.

[0047] 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).

[0048] In particular, "longitudinal" means a direction or plane extending along the main and / or principal direction of the radiating element 1, and "transversal" means a direction or plane extending along a direction perpendicular to the longitudinal direction.

[0049] The radiant element 1 comprises an outer surface 3 b and an inner surface 3 a , and a shaped wall 2 defining an internal cavity 4 .

[0050] The inner surface 3a faces the internal cavity 4. The outer surface 3b faces the inner surface 3a and faces the object to be treated during use.

[0051] The internal 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 within the cavity 4. The main hollow seats 5 have patterns that are parallel to one another and to the main extension L of the radiating element 1.

[0052] The cross section of each main hollow seat 5 has a circular or polygonal shape, for example a square, rectangular, prismatic, hexagonal, octagonal, etc.

[0053] The internal cavity 4 also defines and / or comprises at least one connecting seat 6 capable of connecting at least two main hollow seats 5. The connecting seat 6 is preferably hollow. In alternative embodiments, the connecting seat 6 is closed or filled.

[0054] 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 .

[0055] At least one connecting seat 6 has a substantially polygonal cross section, for example rectangular or square.

[0056] The length of the main hollow seat 5 and / or the connecting seat 6 corresponds substantially to the length of the radiating element 1 .

[0057] In at least one embodiment of the invention, the connecting seat 6 is in fluid connection with at least two main hollow seats 5. Indeed, at least in this embodiment, the internal cavity 4 is unique and is formed by the internal hollow spaces of the at least two main hollow seats 5 and at least one connecting seat 6.

[0058] Considering the transverse extension M of the radiating element 1, the at least two main hollow seats 5 and the at least one connecting seat 6 are arranged in the same plane. They are therefore coplanar. The radiating element itself is coplanar, i.e. has a substantially flat extension.

[0059] Typically, the main hollow seat 5 is located on the outer longitudinal side of the radiating element 1 .

[0060] According to at least one embodiment of the invention, between the main hollow seat 5 and the connecting seat 6 there is at least one (internal) passage or connecting port or opening 7 which puts the seats in communication with e.g. fluids 5, 6.

[0061] These ports or openings 7 are, according to one embodiment of the invention, arranged in the same plane, for example parallel to the plane in which the main hollow seat 5 and the connecting seat 6 are defined and / or located.

[0062] The port or opening 7 is internal in the sense that it does not include the wall 2 of the radiating element 1 .

[0063] The wall 2 of the radiating element is in fact continuous, in at least one embodiment of the invention, and does not have any openings that could connect the internal cavity 4 with the outside, at least in the longitudinal extension L and the transverse extension M.

[0064] In alternative embodiments where the connecting seats 6 are closed or filled, the main hollow seats 5 are not fluidly connected by the connecting seats 6 and may or may not be fluidly connected to each other.

[0065] The radiating element 1 also has two lateral ends 8 located on opposite sides of the longitudinal extension L of the radiating element 1 .

[0066] In at least one embodiment of the invention, end 8 is closed. In particular, as will be better understood below, end 8 of radiant element 1 is closed on one side by a containment element or pad 12 and on the other side by a closure panel 15, which will be better defined below.

[0067] At the lateral ends 8, the radiant element 1 can, in use, be connected to and / or arranged on at least one wall or two walls of the furnace inside which the radiant element is arranged.

[0068] In particular, according to at least one embodiment of the present invention, there is a first transverse end 8a that is placed in the first wall of the furnace when in use, on which there is a support called "furnace side" or "socket" 20, taking into account the conventional designation of furnaces with or without the presence of burners or fume recuperators, and with other systems that do not require classical flame burners (burners and systems that are naturally not present or operational, since the invention according to the present invention is powered differently and / or electrically).

[0069] The socket 20 conventionally consists, in at least one embodiment, of a support fixed to this first wall of the furnace.

[0070] In particular, according to at least one embodiment, the radiant element comprises a support 9 for the radiant element (arranged at the first lateral end 8a of the radiant element itself and fixed and / or restrained, for example, to the closure panel 15) that is supported by and / or movable on a socket 20. This socket 20 may comprise at least a portion or surface or section that can normally be in contact with the support 9. The socket 20 and / or the support 9 may be made of a metallic material that is resistant to high temperatures, for example an austenitic steel material, a high or low nickel content (or high nickel alloy) or a molybdenum or cobalt steel material, a ceramic material, a silicon carbide material, the same material as the radiant element 1, etc.

[0071] These materials have a thermal expansion of 0 mm to 20 mm or more, depending on the temperature of use and their construction.

[0072] In use, the support 9 can be placed, for example, on the internal socket 20 of an existing furnace.

[0073] The support 9 of the radiant element 1 has, according to at least one embodiment of the invention, a shape and size that depends, both with regard to its shape and its positioning, on the socket 20 already present in the furnace.

[0074] In particular, the support 9 can have a tubular or curved or flat structure protruding from the radiating element 1, in the latter two cases being placed on the respective surface of the socket 20, taking into account the base surface depending on the type of socket 20 to which the radiating element 1 can be applied and / or connected.

[0075] For example, as can be seen in Figure 4C, the support 9 can have a support base for the socket 20 that has a curved shape with a concave surface that moves away from the socket 20 itself. This structure of the support 9 can also be defined as a U.

[0076] Precisely because the support 9 depends on the type of socket 20 into which it is inserted and / or placed, the support 9 can be arranged at variable points on the first end 8a and / or can be formed by a single element or by several elements (even one for each main hollow seat 5).

[0077] Furthermore, according to at least one embodiment of the present invention, as anticipated above, at least one closure panel 15 may be present for at least one of the ends 8 of the radiating element 1, for example, located at the first end 8a of the radiating element 1. The closure panel 15 may be part of a metal sheet (e.g., of the same material as the radiating element 1) having a straight or curved shape or other shape.

[0078] If a support 9 is present, the closure panel 15 is able to receive and connect to the support 9 and is able to support (or help support) the weight of the radiant element 1 and the at least one heating means 10 included therein.

[0079] There is also a second lateral end 8b of the radiant element 1, which can be connected to and / or arranged in a second wall of the furnace, for example in a wall facing the first wall of the furnace side (the latter being provided with a furnace side support or socket 20). Burners have traditionally been arranged in the second wall of existing furnaces, for example in a rear position relative to what is defined as a containment element or pad 12 already mentioned in the present invention and better explained below.

[0080] The radiant element 1 according to the invention can in fact also be adapted and connected to the wall of current furnaces which are normally equipped with conventional radiant tubes, using hooks in the existing furnace (so-called furnace side sockets / supports 20). In this way, the user can save costs when retrofitting an entire line, since these furnaces only need to be equipped with heating means other than the conventional heating means, e.g. with the current emission system required for the operation of the electrically operated heating means 10.

[0081] According to one embodiment of the present invention, for example as shown in FIGS. 1, 3, 6A and 7A, the radiating element 1 comprises six main hollow seats 5 and five connecting seats 6.

[0082] In a further embodiment of the present invention, the radiating element 1 comprises three main hollow seats 5 and two connecting seats 6, as shown for example in FIGS. 4A, 8A and 8B.

[0083] In a further aspect of the invention, it is possible to associate two or more radiant elements 1 (e.g., a first or upper radiant element and a second or lower radiant element), each comprising several main hollow seats 5 and one, two or more connecting seats 6, with the same furnace seat (or, as shown below, the same pad).

[0084] According to one embodiment of the present invention, the upper and lower radiating elements each comprise three main hollow seats 5 and two connecting seats 6, each containing three electrical resistors.

[0085] In this way the weight of the entire system is also distributed.

[0086] A (free) space of 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 possible bending or sagging of the upper radiating element. This can further extend the life of the radiating element of the present invention.

[0087] In this case, or according to a further variant of the invention, it is also possible to decide to keep only some of the present heating means 10 functioning, i.e., for example those of the radiant elements, while other means are switched off as required.

[0088] Furthermore, it is also possible to arrange heating means of a certain size and / or power in at least one main hollow seat 5 and to arrange at least one (further) heating means of a smaller size and / or power than the others installed on the same radiant element in at least one other main hollow seat 5, for example located in the lowest part of the radiant element itself when in use.

[0089] In this way it will be possible to reduce the weight and / or deformation caused by the at least one heating means 10 in those parts of the radiant element which are rather more susceptible to deformations precisely due to the weight and / or temperature determined by the heating means 10.

[0090] Naturally, thanks to the properties of the invention, it is possible in each case to ensure uniformity of the heating and therefore of the heat treatment.

[0091] Alternatively, at least one radiant element 1 or multiple radiant elements 1 can comprise less than three or more than three main hollow seats 5, if several radiant elements 1 are associated with the same seat of the furnace (or, as will be seen below, the same pad), and the number of connecting seats 6 depends on the number of main hollow seats 5. For example, according to at least one embodiment of the present invention, if the number of main hollow seats 5 is n, and n is 2 or more, the number of connecting seats 6 is n-1.

[0092] According to further aspects 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, etc.

[0093] In at least one embodiment of the invention, the main hollow seat has a substantially cylindrical or parallelepiped shape, and the connecting seat 6 can have a parallelepiped shape with a polygonal, rectangular, or square base.

[0094] In general, the width of the at least one main hollow seat 5 , taken along the transverse direction M of the radiating element 1 , is greater than the width of the at least one connecting seat 6 .

[0095] 8A and 8B, the width of the at least one main hollow seat 5, considered along the transverse direction M of the radiant element 1, is smaller than the width of the at least one connecting seat 6. However, this aspect of the invention is tailored to the specific needs of the furnace in which the respective radiant element is installed.

[0096] According to at least one embodiment of the present invention, the connecting seat 6, taking into account any port or opening 7, is formed and / or defined by two portions 6a, 6b of the wall 2 having extensions that are parallel to one of the longitudinal directions L of the substantially rectangular shape and that overlap each other.

[0097] These portions 6a, 6b are connected, if desired, without interruption and / or integrally with at least one portion 5a or at least two portions 5a, 5b of the wall 2 forming and / or defining each main hollow seat 5.

[0098] According to at least one embodiment of the invention, at least one portion 5a or two portions 5a, 5b have a concave surface that faces towards the inside of the radiant element and / or towards the internal cavity 4 in use.

[0099] In particular, the main hollow seat 5 connected to the single connecting seat 6 has a single portion 5a with a substantially circular or polygonal cross section corresponding to the cross section of the main hollow seat 5, but with an open cross section at at least one port or opening 7.

[0100] These main hollow seats 5 are the outermost ones and are located on the outer longitudinal sides of the radiating element 1 .

[0101] Instead, if present, the main hollow seat 5, which is connected one by one to the two connecting seats 6, taking into account the transverse extension M of the radiating element 1, is formed and / or defined by two portions 5a, 5b, each having an arc-shaped cross section or a part of a polygon, which together substantially form the cross section of the corresponding main hollow seat 5. Likewise, there are two ports or openings 7, which together with the portions 5a, 5b form a kind of completion of the cross section of the main hollow seat 5. These ports or openings 7 are located on opposite sides, taking into account the transverse extension M of the main hollow seat 5 and the radiating element.

[0102] Obviously, in the embodiment in which the connecting seat 6 is closed or filled, the cross section of the main hollow seat 5 is determined by both the portions 5a, 5b and the possible inner surface that closes the connecting seat 6 (together with the portions 6a, 6b), preventing the connection of the fluid with the main hollow seat 5.

[0103] In particular, portions 6a and 5a constitute a kind of first main or front surface of the radiating element, portions 6b and 5b constitute a kind of second main or rear surface of the radiating element, and the longitudinal sides of the radiating element 1 generally consist of at least one portion 5a having a transverse structure that substantially corresponds to the transverse section of at least one main hollow seat 5.

[0104] According to at least one embodiment of the present invention, the thickness W of the radiating element is not constant. In fact, the thickness can be understood as, for example, the distance W1 between the portions 6a and 6b or the distance W2 between the portions 5a and 5b. The distance W2 is greater than the distance W1.

[0105] According to at least one embodiment of the present invention, the thickness W2 corresponds to the diameter of the circular cross section of the main hollow seat 5.

[0106] According to at least one embodiment of the present invention, the thickness W1 corresponds to the width of the opening or port 7.

[0107] Furthermore, in accordance with at least one embodiment of the present invention, the wall 2 has a thickness of about 5 mm.

[0108] According to at least one embodiment of the present invention, in practice the connection seat 6 is ideally formed by four longitudinal sides, two of which (parallel and opposite) are formed by portions 6a, 6b and the other two by ports or openings 7, thus in effect creating an empty space inside the cavity 4.

[0109] According to an alternative embodiment, the connection seat 6 is formed by four longitudinal sides, two of which (parallel and opposite) are formed by portions 6a, 6b, and the other two are formed by the inner surfaces that actually close the connection seat 6.

[0110] On the other hand, the wall 2 of the radiating element 1 is formed by a single piece of material, for example a molded sheet, that constitutes the radiating element 1 and is composed of the portions 6a, 6b and the portions 5a, 5b. In particular, the wall 2 extends correspondingly to the radiating element 1 and can enclose the internal cavity 4.

[0111] The wall 2 is made in one piece, i.e. by forming (at least) a single piece of sheet metal which is joined together, for example by welding, to create the desired closed structure for the radiating element 1 .

[0112] According to an alternative embodiment, the wall 2 is made by joining together, for example by welding, several pieces of material that make up the radiating element 1, for example two half shells, one front and one rear, to form the desired structure.

[0113] As mentioned above, the wall 2 is shaped to have longitudinal projections corresponding to the main hollow seat 5, and more particularly to its portions 5a, 5b.

[0114] The wall 2 also has portions 6a, 6b between the one portion 5a, 5b and the other portion, which correspond to the connecting seat 6 substantially.

[0115] The portions 6 a, 6 b constituting the connecting seat 6 may be flat or slightly hollow or slightly convex or raised relative to the cavity 4 .

[0116] This shape of the wall 2 corresponds to both the outer surface 3b and the inner surface 3a of the wall 2.

[0117] The fact that the wall 2 is continuous and / or filled, i.e. has no holes or empty areas, allows the radiating element 1 to be more efficient.

[0118] For example, consider conventional radiant tubes, which consist of straight tubes whose ends are joined by curved tubular elements for fumes recirculation. Furthermore, between one straight tube and another (mainly in P, double P, U and double U structures), there is an "empty" area that separates the straight tubes themselves, determining the presence of an "empty" area that does not contribute to the release and / or radiation of heat, and is precisely "empty" and not created by the material from which the tubes of the radiant tube are made. This causes the inefficiency of conventional radiant tubes.

[0119] The same applies to the single tubular elements which are in each case spaced apart from one another.

[0120] Furthermore, with regard to conventional radiant tubes supplied by fuel burners, their temperature is not uniform along their longitudinal extension; in fact, there are very hot areas (burner / flame side), areas of constant temperature drop (fume passage area), and cooler areas (spray exit side).

[0121] These drawbacks are not present in the radiant element according to the invention, and therefore heat transfer is increased (compared to conventional systems) thanks to the distinct fact that the wall 2 is continuous and "filled", and furthermore, in one embodiment, the absence of a burner, but instead the presence of at least one heating means 10, results in a uniform temperature along the entire surface or wall 2 of the radiant element, both from one side to the other and from one lateral end 8a to the other lateral end 8b.

[0122] This advantage can also be achieved if the heating means 10 is supplied with fuel, since the heating means 10 is at least partially housed inside the main hollow seat 5 and contributes to improving the uniformity of heating along the entire surface or wall 2 of the radiant element, both from one side to the other and from one lateral end 8a of the radiant element to the other lateral end 8b.

[0123] Furthermore, by means of different heating and / or power supply it is also possible to increase the temperature that the wall 2 can reach and therefore the heat and heat transfer efficiency of the radiant element 1 according to the invention relative to the ribbon (strip) also increases.

[0124] In at least one embodiment of the present invention, the heating means 10 is not a burner.

[0125] Furthermore, due to these advantages, there is also an increased lifespan of the radiant element 1, since the material from which it is constructed and made has the potential to undergo the same expansion and return movements in the temperature changes required for heat treatment, reducing the possibility of tears (cracks) and stresses in the material itself. Of course, a longer lifespan is determined by reducing these risk factors for the integrity of the radiant element.

[0126] Here again, the measures presented above for the present invention make it possible to reduce power and heating consumption. Indeed, by increasing the heat exchange surface (compared to conventional radiant tubes), less energy is needed to obtain the same result in terms of heat release (lower temperatures). Furthermore, having a uniformity of temperature over the surface of the radiant element allows for better uniformity and quality of the heat treatment of the strip or metal sheet, and also makes it possible to develop new steel grades for each type of market.

[0127] The radiant element 1 comprises and houses at least one heating means 10, for example electrically or fuel powered, as described above, to form the system of the invention. This at least one heating means 10 is housed in at least one main hollow seat 5. In particular, each main hollow seat 5 can contain at least one means 10.

[0128] At least one heating means 10 is removable in the sense that it can also be replaced individually in case of default or inoperability.

[0129] Furthermore, the presence of the means 10 allows, in certain embodiments, easier control of the heat treatment, since the current is constant in its use, unlike combustion burner systems which, as mentioned above, require continuous control of adjustments and emissions resulting from imbalances also created by the various gases and fuels on the market, leading to a significant reduction in management costs compared to the current ones.

[0130] As expected, these new radiant elements make it possible to reduce and / or eliminate harmful emissions of, for example, NOx and CO2, while at the same time reducing the risk to the environment and to operators who have to look at and / or carry out maintenance on the furnace, precisely because an atmosphere inside the furnace that is free from these harmful substances reduces the risk of poisoning through inhalation of toxic gases and fumes.

[0131] The fact that at least one means 10 is contained inside at least one main hollow seat 5 makes it possible to concentrate, with a single element such as the radiant element 1, all the techniques necessary for its heating, and to obtain maximum performance in terms of energy / heat transfer, temperature uniformity and extended life of the radiant element itself.

[0132] The shape of the at least one main hollow seat depends on the shape and / or power of the at least one means 10, for example the at least one electrical resistor or fuel burner.

[0133] In order to decide how many and which means 10 to place in the radiant element, it is necessary to take into account in practice what temperature levels must be reached for the particular heat treatment to be carried out.

[0134] The radiant element 1 according to the invention also comprises at least one reinforcing means 11, preferably arranged inside the at least one main hollow seat 5 and / or inside the connecting seat 6, so as to be able to accommodate at least one heating means 10 inside. The purpose of this reinforcing means 11 is to help support and / or fix the at least one means 10 in position.

[0135] The reinforcing means 11 comprises at least one plate, screw, bolt, rod, pin, peg or other similar reinforcing member, which may be fixed, welded or press-fit onto the inner surface 3a and / or outer surface 3b of the radiating element 1, and / or onto at least one of the portions 6a, 6b of the at least one connecting seat 6 and / or onto at least one of the portions 5a, 5b of the at least one main hollow seat 5. The reinforcing means 11 is preferably internal or mostly internal.

[0136] The at least one reinforcing means 11 may have the shape of a cylinder, a cone, a flattened, a parallelepiped, a prism, etc.

[0137] According to a particular embodiment of the invention, at least one reinforcing means 11 is arranged in (in) part 6a and / or part 6b of at least one connecting seat 6. In this way, it is possible to reduce the effects of expansion (swelling) of the radiating element itself, as well as the effects of deflection and distortion of the material of which the radiating element is made.

[0138] According to at least one embodiment of the present invention, the reinforcing means 11 are multiple or a series, arranged spaced apart from one another along the entire longitudinal extension of the radiating element 1, preferably on the connection seats 6, or on at least one of them. Such reinforcing means are shown in detail, for example, in Figure 4B. As can be seen from this exemplary image, according to one embodiment of the present invention, the reinforcing means 11 are shaped like pins, the ends of which are fixed to each part 6a, 6b of the connection seat 6.

[0139] 6A, the reinforcing means 11 may be in the form of a plate 11a arranged along the longitudinal direction of the radiating element 1. Furthermore, as can be seen from this exemplary figure, said reinforcing means 11a in the form of a plate is arranged in at least one connecting seat 6, preferably in a lower or lower position, having regard to the radiating element 1 installed in use.

[0140] The number, length and arrangement of the reinforcing means 11a can vary depending on the needs of the reinforcement itself.

[0141] The means 11a may of course allow fluid communication inside the cavity 4 and may therefore be provided with slots or other openings to allow the passage of air or other gases contained inside the radiant element 1 and thus ensure uniformity of heat transfer.

[0142] In at least one embodiment of the invention, the reinforcing means 11 comprises both pins and / or pegs and plates 11a.

[0143] Indeed, the weight of at least one means 10, e.g. a respective electrical resistance or a fuel burner, can be problematic in the radiant element 1 according to the invention, since at high temperatures the material used for the radiant element itself can lose its ability to support the weight, and therefore the radiant element 1 can be deformed and / or damaged if required to support an excessive weight.

[0144] According to at least one embodiment of the present invention, the area of ​​the heating means 10 that is most susceptible to deformation due to high temperature and / or weight is located below and / or at the first end 8a (taking into account the radiant element 1 installed in use).

[0145] According to one embodiment of the invention, the means 10, e.g., an electrical resistor, comprises a plurality of longitudinal wires or electric plates 10a (arranged adjacent to one another) through which an electric current passes (e.g., as can be seen in Figures 5A and 5B). The plurality of wires or plates is held in place and supported by at least one disk or at least one plate 10b. The disk or plate 10b has at least one hole in its central part for the passage of the electric wires 10a (Figure 5A), which must not come into contact with each other (as also happens with electric plates) and / or with materials arranged nearby, e.g., the inner surface of the radiating element 1 (to reduce the risk of short circuits).

[0146] This disk or plate 10b therefore has an outer portion 10c, if desired in the shape of a ring, which separates the wire or plate 10a from the surrounding environment. According to at least one embodiment of the invention, the disk or plate 10b and / or its outer portion 10c rests on the inner surface 3a of the radiating element present in at least one main hollow seat 5. Thus, in practice, it rests on the inner surface 3a in portions 5a, 5b of at least one main hollow seat 5.

[0147] This disk or plate 10b is made of a refractory material, for example a ceramic material.

[0148] On the other hand, in embodiments in which the heating means 10 comprises a fuel burner, the heating means 10 comprises a disc or plate or other suitable means, which has a portion that can rest, if desired externally, on the inner surface 3a of at least one portion 5a, 5b of the main hollow seat 5, or on another suitable seat of the radiant element 1, or on at least one wall of the furnace. Alternatively, the heating means 10 in the form of a fuel burner can be fixed to at least one of the lateral ends 8 of the radiant element so as to be fixed in place without contacting the inner surface 3a.

[0149] The at least one reinforcing means 11, 11a therefore supports and distributes the weight of the means 10, for example along the longitudinal extension L of the element itself, as required. In particular, in practice, according to at least one embodiment of the present invention, the at least one means 10 is not in contact with the at least one reinforcing means 11, 11a. The latter are in fact, for example, arranged in series along the extension of the at least one connecting seat 6, keeping the distance between the portions 6a, 6b constant and preventing the radiating element, at least in some parts thereof, from opening or increasing its thickness W and causing a consequent displacement of the at least one means 10 contained therein.

[0150] In this way, the presence of at least one reinforcing means 11, 11a reduces breakage of the disk or plate 10b of the means 10, reduces deformation of the radiating element 1 and reduces sliding of the disk or plate 10b relative to the radiating element 1 itself.

[0151] By "sliding" is meant expansion movement, for example by elongation, caused by the high operating temperatures to which the materials are subjected during processing (as parts of different materials also have different elongations at elevated temperatures).

[0152] Naturally, by ensuring a lower default of the components involved, thermal efficiency is ensured over time.

[0153] The at least one reinforcing means 11, 11a may be a separate element placed on the inner surface 3a of the radiating element or may be part of the radiating element 1 itself, in the sense that it can be obtained by bending and special construction of the metal sheet from which it is made.

[0154] Naturally, the number and arrangement of the electric wires, or the number and cross-section of the electric plates (which may have a circular cross-section or assume any shape and form), or the shape and size of the fuel burner will also change the shape and size of the disc or plate 10b and therefore the shape and size of the at least one reinforcing means 11, 11a.

[0155] The at least one heating means, when in the form of an electrically powered means 10, can have different shapes and structures, to which the radiating element 1, or rather the at least two main hollow seats 5, are adapted, or vice versa.

[0156] Current supply cables can exit from the at least one heating means 10. These cables are directed, for example, towards the second end 8b of the radiating element 1. The latter therefore only requires an area for the inlet and / or outlet of the supply cables of the at least one means 10 (for example located at the second end 8b).

[0157] In particular, these cables are placed on the pad 12 and / or terminate outside the pad 12. The same is true if the at least one heating means 10 is in the form of a fuel burner.

[0158] The means 10 may have an inner end, if desired, extending substantially a few centimetres from a closure panel 15 located at the first end 8 a of the radiating element 1 .

[0159] As mentioned above, each main hollow seat 5 can accommodate one, two, three, four, five, six or more means 10 therein, depending on its size and the power required to heat it.

[0160] The radiant element 1 also comprises, at its second end 8b (or outlet end), the aforementioned storage element 12. The storage element 12 is located rearward relative to the radiant element 1. It is made of a box-like element, preferably made of metal, known in technical terms as a "pad." It is resistant to high temperatures and has a protective system for the exterior and / or outer areas. This protective system can comprise a coating or covering material, such as a fabric, molded, for example, as stainless steel sheeting for the inner walls of the furnace, or iron for the outer walls of the furnace itself. If desired, such a protective system can include materials made of or based on biological fabrics and / or ceramic materials, which can prevent heat transfer outside the radiant element 1 and / or the furnace in which it is installed.

[0161] Thus, the storage element 12 is arranged outside the furnace and the radiant elements are arranged above it, for example at their second ends 8b.

[0162] The containment element 12 and / or the protection system may also, if desired, comprise a covering element made of metal sheet for covering the electric cables of the means 10 to protect the furnace operator, for example to avoid short circuits or accidental damage.

[0163] The pad is therefore thermally insulated.

[0164] Furthermore, the positioning of the at least one means 10 relative to the pad also serves as protection for the workers on site: indeed, the at least one means 10 reaches a very low temperature in its initial section (facing the second end 8b of the radiant element) and ensures a heat emission towards the outside of the furnace (the working area of ​​the operator) that is lower than 85°C.

[0165] This is certainly not possible with conventional radiant tube systems, where the external temperature parameters are also regulated by strict standards for this matter. The present invention, thanks to the aforementioned inventions, is also able to meet these requirements.

[0166] The gas-tight closure of the furnace and heating system from the outside can be achieved, for example, by a series of one or more flanges 13 shaped according to the number of means 10 to be inserted, or by a single flange 13. This at least one flange is located on the rear side of the radiant element 1, i.e. at its second end 8b.

[0167] It is possible to have a flange 13 on each means 10, or on some or all of the means 10. According to at least one embodiment of the present invention, at least one flange 13 is located only on the pad 12 and / or the second end 8b and / or can be used to fasten the respective means 10, for example by screws and bolts.

[0168] In this way, the electrical resistance and / or the number of replacements of the at least one means 10 is reduced, resulting in greater safety for the operator when replacement of such at least one means 10 is required.

[0169] Furthermore, in at least one embodiment of the present invention, at least one flange 13 may include at least one external compensator, the function of which is to allow for any required expansion of the radiant element 1 even towards the outside of the furnace itself (they are capable of expansion of about + / - 5 cm).

[0170] According to at least one embodiment of the present invention, the shape of the radiating element 1 may differ taking into account the inner surface 3a and the outer surface 3b, since the radiating element 1 may be provided with reinforcing and / or strengthening means such as longitudinal, transverse and / or horizontal corrugations, studs, ribs, grooves of any shape and size, etc.

[0171] These reinforcing and / or strengthening means may be arranged and / or made on the inner surface 3 a and / or on the outer surface 3 b of the radiating element 1 .

[0172] These reinforcing and / or strengthening means can be obtained directly from the shaping of the metal sheet constituting the radiating element 1, for example by calendering or pressing using suitable dies, or by the successive application of welding or other known fastening systems.

[0173] These reinforcing and / or strengthening means can serve to strengthen the material of the radiating element 1 and thus ensure a longer lifespan thereof.

[0174] Figures 6B and 7B show two examples of external type reinforcing and / or strengthening means, i.e. reinforcing and / or strengthening means 14, respectively, covering only a part of the outer surface of the radiating element 1 (Figure 6B shows, in particular, that when in use, starting from the bottom, it is arranged in three or four main hollow seats 5, and therefore has a kind of U-shape that, starting from the bottom, at least partially includes both the front and rear faces of the radiating element 1), or the entire outer surface of the radiating element (Figure 7B shows that the reinforcing and / or strengthening means 14 encompasses the entire circumference of the radiating element, taking into account its transverse extension M, both with respect to the front and rear faces of the radiating element 1). The reinforcing and / or strengthening means 14 may be made of a material resistant to high temperatures, for example selected from the possible materials for the radiating element 1, for example a high-alloyed or low-alloyed material, or a material highly or alloyed with nickel, molybdenum or cobalt, or a material without these, such as Inconel 600 / 601 / 602, Avesta, Alloy 800H, AISI 309 / 310 / 316 / 321, Kanthal APM / APM-T, Al, or at least one material obtained by melting / casting, forging, extrusion, or any other material available for this purpose.

[0175] The reinforcing and / or strengthening means 14 may have an extension of a length equal to the main longitudinal extension L of the radiating element 1, or they may be arranged only in a part of the radiating element 1, for example in a central position and / or at the ends 8a, 8b (preferably 8a) of the radiating element 1, or at a point of the radiating element 1 where some loads related to the temperature and / or weight of the at least one means 10 that the radiating element contains may occur.

[0176] The reinforcing and / or strengthening means 14 have the purpose of stiffening the structure of the radiating element 1, for example at least one of its ends 8, in order to reduce or avoid any kind of twisting or deformation of the whole structure or parts thereof. In at least one embodiment of the invention, the means 14 are arranged on the outer surface 3b of the wall 2 of the radiating element 1.

[0177] In embodiments where the radiant element 1 is arranged in the furnace in a horizontal position (it is to be considered that the positions indicated above generally refer to the positioning of the radiant element in the furnace in a vertical position or both in a vertical and horizontal position, unless expressly indicated otherwise), the reinforcement and / or strengthening means and / or at least one reinforcement means 11, 11a are arranged on the upper (or ceiling-facing) and / or rear (or ground-facing) face of the radiant element 1 in use. In this case, the reinforcement and / or strengthening means and / or at least one reinforcement means 11, 11a may be in the form of plates, ribs or longitudinal grooves, corrugations, bosses, protrusions and / or fixed objects, etc., arranged on the outer and / or inner face of at least one main seat 5, and / or facing upward and / or downward and protruding inward and / or outward, correspondingly welded to the radiant element or the shape of the material that makes up the element, having a length corresponding to the length of the radiant element considering its longitudinal extension, or segments with a regular or irregular pitch according to specific areas requiring greater reinforcement and / or strengthening, etc.

[0178] The radiant element 1 can be formed and / or shaped by pressing a metal sheet, by calendering at least a portion of the radiant element 1, and / or can be obtained by melting, centrifuging, forging and / or modeling at least one metal that constitutes it, etc.

[0179] Due to the particular shape and / or manufacturing method of the radiating element according to the invention, there are very few cuts in the material from which it is made and, consequently, few welded parts.

[0180] Consider, for example, a conventional, e.g., W-shaped, radiant tube, consisting of, e.g., four longitudinally welded straight tubes, three curved tubular sections formed into two halves welded internally and externally, and four or more circumferential welds for joining the various elements, whereas a radiant element according to at least one embodiment of the present invention may comprise a single longitudinal weld, e.g., for joining two longitudinal edges of a sheet cut to a suitable size and shape, to join the walls 2 and define the formation of the internal cavity 4.

[0181] The radiant element 1 according to the invention, in at least one embodiment of the invention, can consist of at least one shaped sheet (to form portions 5a, 5b and portions 6a, 6b) or 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 installed (e.g., when installed in an existing furnace).

[0182] The wall 2 of the radiating element 1 therefore consists of and / or forms, in at least one embodiment of the invention, at least one shell or two or more half shells mounted on the same storage element 12 (pad).

[0183] If the connecting seats 6 are hollow, they constitute a kind of empty space within the internal cavity 4, which allows the passage of heat between one means 10 and the other, and between one main hollow seat and the other. In this way, the temperature is homogenized along the entire surface of the radiant element 1, which also ensures a uniform expansion and growth of the material, reducing stress and fatigue in the radiant element and significantly increasing its service life.

[0184] Furthermore, the presence of the connecting seat 6 has the function of supporting the means 10 and allowing the means to expand due to an increase in temperature. The connecting seat 6 in fact has a thickness W1 less than the thickness W2 of the main hollow seat 5, as mentioned above, and forms a kind of constriction inside the cavity 4, in which the disk or plate 10b of the heating means 10 powered by electricity or fuel and / or the at least one reinforcing means 11, 11a rests.

[0185] The width of the portions 6a, 6b (obtained taking into account the transverse direction of the radiating element 1) may be a few centimetres, or between 1 cm and 5 cm, or between 1 cm and 25 cm.

[0186] As mentioned above, in both cases the entire wall 2 of the radiant element 1, including the portions 6a, 6b, is heated, thus ensuring temperature uniformity and improved heat transfer thermal efficiency.

[0187] Thus, it has been seen how the present invention achieves its intended goals.

[0188] The radiant element 1 according to the invention has practically a uniform temperature along its entire length and has an increased mass or radiating surface, for example by more than 65%, compared to radiant tubes currently available on the market.

[0189] For example, the W-shaped radiation tube is 5.6 m 2 It has a total surface area of ​​3.7m 2 whereas the radiating element 1 according to the invention has a maximum exchange surface of 7.7 m 2 and has a total surface area of ​​at least 6.1 m 2(considering the same furnace for the same length). Obviously, these values ​​will vary from furnace to furnace, as each furnace has a different distance between its walls, but the surface advantage remains proportional to the wall-to-wall distance (i.e., the distance between the walls). This allows for the following advantages:

[0190] A. Reduced consumption: for example, a gas burner has an average / maximum efficiency of 75-80%, while the efficiency of a heating means using, for example, a power supply 10 is 90-100%. Therefore, if you want to replace a burner with a power of 150 kW, a resistor with a power of up to 110 / 120 kW will be sufficient and you will get the same heating result (of course, the power can be even higher, up to 200 kW or more, if necessary). B. Management of the radiant elements: The radiant mass (or surface) and the at least one heating means 10 have the potential to support all needs and are highly efficient, making it possible to adjust their use according to the actual heat treatment needs of the strip. C. Improving the quality of the heat treatment and therefore of the ribbons passing through: this is achieved thanks to the uniformity of radiation and heat release obtained thanks to the radiating element according to the invention, which may increase and improve the technical and mechanical properties of the ribbons for even more extreme uses in the industries to which they are subsequently applied (for example, in the automotive and / or aerospace sectors, as well as for impact resistance, obtaining materials with increasingly greater creep resistance that can withstand increasingly strong impacts and stresses). Materials treated with the radiating element according to the invention are therefore better in terms of physical and mechanical properties, more reliable, durable over time and more resistant. D. Ease of Use: This is obtained, for example, according to one embodiment, with respect to combustion systems that require ongoing maintenance and replacement of burner parts (e.g., heads, nozzles, recuperators, ceramic and consumable parts, etc.). E. System Computerization and Standardization: With the radiant element thus designed, the amount of energy required to heat the radiant element can be entered via a dedicated software system, allowing for the necessary differentiation of heating zones, maintaining the required temperature uniformity for both the structure and radiant mass / surface as well as the internal heating element, while significantly reducing the current or fuel required to heat the radiant element itself. For example, if there are several heating means 10, such as six electrical resistors or six fuel burners, they can be operated intermittently or as needed, for example, by turning on resistors 1, 3, and 5 while keeping resistors 2, 4, and 6 off, or by subsequently reducing their power output to repeat the same operation in reverse, i.e., by increasing the power output of resistors 2, 4, and 6 and reducing the power output of the other resistors 1, 3, and 5. The same can be achieved with fuel burner-type heating means 10. F. Energy efficiency and reduction / elimination of harmful emissions: In addition to those related to the radiant elements themselves, also the level of generation of the electrical energy required for their operation is subject to certain embodiments of the invention. Indeed, as mentioned above, reducing consumption saves electricity or fuel and therefore reduces the emissions of CO2 into the atmosphere for production plants (electric plants, nuclear plants and any other form of energy production). G. Low power required for the heating means 10, e.g., electrically operated: Due to the above advantages and the possibility of using several electrical resistors (3, 6, 9, or even 12 or more, depending on the dimensions of the radiant elements and the heat treatment needs), each heating means 10 and / or each internal electrical resistor may require a power output ranging from 10 or 17 kW to 30 kW or even 50 kW or more, if desired. This also reduces power consumption, increases control possibilities, and allows for the possibility of selecting the dimensions and shape of the resistors themselves. It also allows for the radiant elements to be smaller in size compared to conventional radiant tubes, ultimately making it possible to research new furnaces with smaller dimensions than current ones. H. Reduction of stress on heating means: Having the possibility to switch off or reduce the power of some means 10 and / or some electrical resistances or combustion burners eliminates the need for continuous operation at 100% of their power, preserving the physical breakdown of the materials from which they are made and reducing the need for their replacement, thus also reducing costs for the user. Furthermore, the reduction in energy required entails benefits for all connected components, such as the substations that transform the current and supply it to the resistances in the system, the current-carrying cables that are less loaded and can be smaller in size, and finally resulting in savings in the overall management of the entire system. I. Reduced risk of explosion and leakage: Due to lower power requirements and reduced stress. J. The possibility of using renewable energies or energy obtained from renewable sources: for the production of electricity, in addition to current power plants, it is possible to use solar power, wind energy, nuclear energy, etc. The same applies to fuels, which may be from renewable sources or may be neutral in terms of CO2 emissions, etc.

[0191] It can therefore be seen that the above advantages are not available with the solutions known from the prior art.

[0192] The distinctive feature of the radiant element according to the invention is the fact that it distributes the energy emitted by the heating means 10 (i.e. by an electrical resistance according to at least one embodiment of the invention or by a burner) through and over a surface (such as the wall 2) that is much larger than a standard tube formed, for example, by individual tubes with a circular cross section.

[0193] According to the embodiment in which the heating means 10 is electrically driven, it is preferable that the resistance is between 2.2 and 2.5 W / cm 2 , taking into account the material of the radiating element itself, in terms of mechanical properties. 2 and / or 3.0-3.5W / cm 2It is preferable that the power does not exceed 100 W. The high power required for the transfer of energy, i.e. heat, from the radiant element to the metal sheet ribbon or other material for heat treatment instead requires greater power and / or increasingly powerful resistors (from the classic 20 kW to 40 kW and even 60 kW). This power cannot be tolerated by resistors in terms of mechanical properties and fatigue resistance, nor by conventional tubes with reduced surface area, such as single tubes with a circular cross section.

[0194] On the other hand, the radiant element according to the invention, in at least one particular embodiment, increases the radiating surface by more than 70% with respect to standard solutions (considering also a pipe with a diameter of 200 mm on the same pad), thanks to the fact that it mechanically "receives and supports" the power provided by the heating means 10, replacing it without stressing the substrate of the radiant element itself. Furthermore, in addition to the improved results, the manufacturing costs are very competitive, lower than for example the pipes sold by the company Kanthal (which, in the case of a material composed of iron, chromium and aluminum alloys, can reach a thickness of up to 9 mm, but which, at least above a certain threshold, are inefficient in terms of heat exchange in the context of the present invention).

[0195] Furthermore, according to at least one embodiment of the present invention, when considering the system as a whole, a radiant element can be defined as a type of casing containing heating means 10, for example electric resistance or fuel burners, not singly as in the known type of single radiant tube, but multiple.

[0196] Finally, the radiant element according to the invention is able to generate approximately 120 Kw or up to 240 Kw (as stated above in W / cm ) of heat generated by the heating means 10 . 2 (subject to the parameters of

[0197] This power is required for each radiant element and, thanks to the present invention, it is possible to significantly reduce the mechanical and fatigue stresses exerted on the material of the radiant element, thus leading not only to an active and effective transfer of heat towards the strip or material to be treated, but also to a longer lifespan of the radiant element itself (compared, for example, to a metal sheet tube of circular cross section).

[0198] The invention also relates to a radiant element 1 and / or a radiant system consisting of a plurality of radiant elements 1 and a relative number of heating means 10, and to their use in heat treatment.

[0199] Features described with respect to one aspect or embodiment or configuration of a component of the invention may also be present in one or more other aspects or embodiments or configurations of the component of the invention without thereby departing from the scope protection afforded by the following claims.

Claims

1. A radiating element (1) usable in at least one furnace for heat treatment and / or for a continuous galvanizing and annealing line of sheet metal 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, wherein the radiating element (1) is used to release and / or radiate heat, and the radiating element (1) comprises a main longitudinal extension (L) and a transverse extension (M) perpendicular to the main longitudinal extension (L) A radiating element having a molded wall (2) defining an outer surface (3b), an inner surface (3a), and an internal cavity (4), wherein the inner surface (3a) faces the internal cavity (4) and the outer surface (3b) faces the inner surface (3a), and the cavity (4) comprises at least two main hollow seat portions (5) adapted to accommodate at least one heating means (10) when in use, and the radiating element (1) also comprises at least one connecting seat portion (6) of the at least two main hollow seat portions (5).

2. The radiating element (1) according to claim 1, wherein each of the at least two main hollow seat portions (5) and the at least one connecting seat portion (6) is parallel to each other and has a main longitudinal extension portion parallel to the main longitudinal extension portion (L) of the radiating element (1).

3. The radiating element (1) according to claim 1, comprising n main hollow seat portions (5) where n is greater than 2 and n-1 connecting seat portions (6), or the radiating element (1) comprising three main hollow seat portions (5) and two connecting seat portions (6) or six main hollow seat portions (5) and five connecting seat portions (6).

4. The radiating element (1) according to claim 1, wherein the at least one main hollow seat portion (5) has a cross-section that is circular, or polygonal, such as a square, rectangle, prism, hexagon, octagon, and / or substantially cylindrical or parallelepiped, and / or the at least one connecting seat portion (6) has a cross-section that is substantially polygonal, such as a rectangle or square, and / or parallelepiped with a polygonal, rectangular or square base.

5. The radiating element (1) according to claim 1, wherein the cavity (4) is formed by the at least two main hollow seat portions (5) and the at least one connecting seat portion (6) which is therefore hollow.

6. The radiating element (1) according to claim 5, wherein at least one port or opening (7) for the passage and / or connection of fluid between the at least two main hollow seat portions (5) and the at least one connecting seat portion (6) is located inside between the at least one main hollow seat portion (5) and the at least one connecting seat portion (6).

7. The radiating element (1) according to claim 1, wherein the wall (2) is continuous and does not have an opening that allows the internal cavity (4) to communicate with the outside, at least with respect to the main longitudinally extending portion (L) and the transversely extending portion (M).

8. The radiating element (1) according to claim 1, wherein the wall (2) comprises at least two portions (6a, 6b) defining the at least one connecting seat portion (6) and at least one portion (5a, 5b) defining each of the at least two main hollow seat portions (5).

9. The radiating element (1) according to claim 8, wherein the at least two portions (6a, 6b) are substantially flat or curved, and the at least one portion (5a, 5b) has a concave surface facing the inside of the radiating element (1) when the at least two main hollow seat portions (5) are positioned outside the radiating element (1) and at opposing longitudinal ends.

10. The radiating element (1) according to claim 1, comprising two lateral ends (8) located on the opposite side of the main longitudinal extension (L), the two lateral ends (8) each comprising a first end (8a) having, for example, a "furnace-side support" or "socket" (20) suitable for connection to and / or placement on a first wall of the furnace when in use, and a second end (8b) suitable for connection to and / or placement on a second wall of the furnace opposite the first wall when in use, the radiating element (1) comprising a support (9) for the radiating element (1) located on the first end (8a) and a storage element or pad (12) located on the second end (8b).

11. The radiant element (1) according to claim 1, comprising a heating means (10) powered by at least one electric or fuel to heat the radiant element (1), wherein the at least one heating means (10) is housed in at least one or each of the at least two main hollow seat portions (5).

12. The radiating element (1) according to claim 11, wherein the at least one electrically heated means (10) comprises at least one electrical resistor or resistor and / or a plurality of longitudinal electrical wires or electrical plates (10a) through which current passes, the plurality of longitudinal electrical wires or electrical plates (10a) are held in place and supported by at least one disk or at least one plate (10b) made of a refractory material such as ceramic material.

13. The heating means (10) powered by at least one fuel comprises at least one burner powered by the fuel, such as gas, hydrogen, methane, biofuel, zero-emission fuel, e-fuel, or "carbon-neutral" synthetic fuel, according to claim 11.

14. The radiating element (1) according to claim 1, comprising at least one reinforcing means (11, 11a) for supporting and / or holding the radiating element (1) in a predetermined position, preferably inside the main hollow seat portion (5) and / or inside the at least one connecting seat portion (6).

15. The radiating element (1) according to claim 14, wherein the reinforcing means (11) comprises at least one plate (11a), screw, bolt, rod, pin, peg, or other similar reinforcing element and / or has a shape such as cylindrical, conical, flat, parallelepiped, or prism, and / or the at least one reinforcing means (11, 11a) is fixed, welded, or press-fitted into the inner surface (3a) and / or the outer surface (3b) and / or the at least one portion (6a, 6b) and / or the component (5a, 5b).

16. The radiating element (1) according to claim 1, wherein the cavity (4), the at least one main hollow seat portion (5), and the at least one connecting seat portion (6) extend along the entire main longitudinal extension portion (L) of the radiating element (1).

17. The radiating element (1) according to claim 1, comprising a molded flange (13) located at the second lateral end (8b) of the radiating element (1), at least one compensator, reinforcing means and / or strengthening element (14), at least one of U-shaped elements arranged or fabricated together with the inner surface (3a) and / or the outer surface (3b), such as longitudinal, transverse and / or horizontal corrugations, bosses, ribs, grooves, etc.

18. A radiation system for at least one furnace for heat treatment, and / or for a continuous galvanizing and annealing line for sheet metal strips or plates and / or other products made of steel and / or other metals, and / or for the modernization of at least an existing furnace, comprising at least one radiation element (1) as described in any one of claims 1 to 17, and at least one heating means (10) or at least two heating means (10) for heating the at least one radiation element (1) to or beyond 1200°C and enabling the at least one radiation element (1) to emit and / or radiate heat during use.

19. Use of the radiating system according to claim 18, for performing heat treatment of sheet metal strips or plates and / or other products made of steel and / or other metals in a heat treatment furnace, and / or for a continuous line of galvanizing and annealing, and / or for a modernized existing furnace, wherein the at least one radiating element (1) emits and / or radiates heat toward the sheet metal strips or plates and / or other products made of steel and / or other metals to determine the heat treatment for the sheet metal strips or plates and / or other products made of steel and / or other metals.

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