Patent Application
20240288221
This patent application claims priority from Italian patent application no 102021000016334 filed on Jun. 22, 2021 and from the Italian Patent Application No. 102021000016352 filed on Jun. 22, 2021, the entire disclosures of which are incorporated herein by reference.
The present invention relates to a heating assembly and apparatus for the firing of ceramic articles. In particular, the present invention is advantageously, but not exclusively, applied to the firing of ceramic articles to obtain tiles, which the following description will make explicit reference without thereby losing generality.
The firing of ceramic articles to obtain tiles generally takes place in tunnel kilns, delimited by two opposite walls and a roof.
Such kilns are usually heated by two sets of burners typically running on methane gas, each arranged on one side of the tunnel. These burners are usually located on the side walls of the tunnel on several levels and face the opposite wall, and the ceramic articles are usually transported on a large conveyor consisting of a series of ceramic rollers.
The firing cycle of ceramic articles is designed with great precision and involves: heating the ceramic articles starting from the kiln entrance, holding them inside the firing chamber at a predefined temperature and cooling them in a controlled manner before reaching the kiln exit. Consequently, it is important to ensure that the temperature inside the firing chamber is uniform throughout the width of the kiln. For this purpose, different types of industrial burners have been developed, as well as different burner arrangements within industrial apparatuses, in order to achieve an increasingly constant temperature within the firing chamber.
However, ceramic burners of the known type are essentially fueled with fossil fuels (methane, LPG), which, although, on the one hand, allow NOx emissions to be reduced through normal combustion, on the other hand lead to an anti-ecological exploitation of non-renewable resources and emission of CO2 and of all other combustion waste products.
In an attempt to overcome these problems, methods have been developed for electrically heating kilns for the firing of ceramic articles, involving, for example, the installation of heating rods or heating conductors in the kiln compartment to radiate heat and heat the kiln itself.
However, even such known firing methods have some disadvantages. One of the main disadvantages is related to the aggressive nature of the fumes generated by the firing of the ceramic articles, especially in the pre-heating area of the kiln itself, which induce rapid erosion of the heating rods or heating conductors installed in the kiln, thus forcing frequent maintenance or replacement of such heating elements. In order to try to overcome such a problem, such heating rods or heating conductors are generally installed only in the firing area of the kiln, where the fumes produced are not highly chemically aggressive, while in the pre-heating area, industrial burners of the known type are used.
Furthermore, electrically heating kilns for the firing of ceramic articles is more expensive than oil or gas, regardless of whether the electricity is used from the grid or internally.
A further disadvantage of the known methods for electrically heating kilns for the firing of ceramic articles is the often excessive radiation effect, which does not allow for uniform heat distribution in large combustion chambers.
Yet another disadvantage of the known methods for electrically heating kilns for the firing of ceramic articles is related to the impossibility of firing the body of the ceramic article uniformly throughout t its section. In particular, with the known methods, only ceramic articles up to 6 mm thick can be fired evenly throughout the thickness.
Aim of the present invention is to make a heating assembly and an industrial apparatus for the firing of ceramic articles which make it possible to overcome, at least partially, the drawbacks of the prior art, while at the same time being easy and cheap to realise and resulting in at least a reduction of CO2 emissions.
According to the present invention, a heating assembly and an industrial apparatus for the firing of ceramic articles as claimed in the attached independent claims, and preferably, in any one of the claims dependent directly or indirectly on the mentioned independent claims, are put forth.
The claims describe preferred embodiments of the present invention forming an integral part of the present description.
The invention will now be described with reference to the accompanying drawings, which illustrate some non-limiting embodiments, wherein:
In the accompanying figures, the reference number 1 globally denotes a heating assembly for the firing of ceramic articles T according to a first aspect of the present invention.
In detail, in the present specification, ceramic articles T are understood to mean any type of article made of ceramic material that requires at least one firing cycle in an industrial kiln 2 (such as the one partially illustrated in
The heating assembly 1 may be installed in an industrial kiln 2, in particular in a tunnel kiln 2, comprising a firing chamber 3.
In particular, as schematically illustrated in
According to some advantageous but non-limiting embodiments, the transport system 4 comprises a series of rollers arranged in succession along a direction parallel to the conveying path P, on which the non-fired ceramic articles T to be fired are arranged, preferably in an orderly fashion.
In detail, advantageously but not limitedly, the transport system 4 comprises a plurality of ceramic rollers (possibly also moving at different speeds to differentiate the firing of the articles) arranged in succession along the conveying path P (i.e. along the direction parallel to the conveying path P) so as to define a conveying plane intended to receive the ceramic articles T and move them along conveying path P.
Referring in particular to
In detail, advantageously, the gas G comprises (in particular, consists of) ambient air with, for example, at least 21% oxygen.
Advantageously, but not limitedly, the electric heater 5 further comprises at least one support (not visible in the appended figures) attached inside the tubular casing 6 and configured to support at least the electric heater element so as to keep it stationary with respect to the tubular casing 6.
Such an arrangement of the electric heating element within the casing 6 protects the electric heating element from the chemical aggression of any fumes and/or waste gases from the firing chamber 3, increasing the service life of the heating assembly 1 compared to the known electric heating assemblies for the firing of ceramic articles T.
According to some advantageous but non-exclusive embodiments, the mentioned support comprises (in particular, consists of) a rod; even more advantageously, a plurality of rods arranged to define between them a plurality of hollow channels. Advantageously but not limitedly (in this case), the electric heater element comprises (in particular consists of) an electric wire, such as a Kanthal wire, wound around each/the rod and configured to heat by the Joule effect the gas G flowing through the tubular casing 6.
According to alternative embodiments, the support element comprises a plurality of pierced spacers (not visible in the appended figures) extending radially with respect to the tubular casing 6 and following one another along a longitudinal axis X of the tubular casing 6 itself so as to define a plurality of longitudinal channels that are open at least at the ends.
Furthermore, advantageously but not limitedly, the electrical heater element comprises (in particular, consists of) an electric wire, such as a Kanthal wire, which extends through the holes, e.g. helically wound into the several adjacent holes, and configured to heat by the Joule effect the gas G passing through the tubular casing 6.
According to some advantageous but non-limiting embodiments, the electric heater 5 further comprises an insulating layer (not visible in the appended figures) arranged at an end 9 of the tubular casing 6, opposite the end 7, and provided with an opening (not visible in the appended figures) configured to allow the gas G to flow out of the tubular casing 6. Advantageously, but not limitedly, such opening is configured to fluidically connect the electric heater 5 with a tubular discharge element 10, which will be better described below.
Advantageously but not limitedly (according to some embodiments not illustrated), the heating assembly 1, in particular the electric heater 5 further comprises at least one temperature control device (not illustrated) and advantageously comprising at least one thermocouple for detecting the temperature (of the gas G) inside the electric heater 5. Alternatively or in combination, the heating assembly 1, in particular the electric heater 5 additionally comprises at least a control unit (not illustrated) to control (in a known manner), possibly depending on the data recorded by the temperature control device, the operation of the electric heater 5.
According to some advantageous but non-limiting embodiments, the electric heater 5 is a commercially known product described in one of the following Patent documents WO2020193479, EP3721150 and EP3721149.
Advantageously, but not limitedly, the heating assembly 1 further comprises a tubular discharge element 10 extending from the tubular casing 6 of the electric heater 5, on the opposite side relative to the feeding duct 8 (in particular, extending from the end 9 of the electric heater 5), is configured to receive and to be flown through by the gas G flowing out of the electric heater 5, and comprises at least one leading outlet 11 for leading at least part of the aforementioned gas G towards the outside of the tubular discharge element 10 (in particular, towards the outside of the heating assembly 1; even more particularly, in use, towards said firing chamber 3 of the kiln 2).
Advantageously, such leading outlet 11 has a through-hole with an equivalent diameter smaller than or equal to approximately 25 mm. More advantageously, but not limitedly, the through-hole of the leading outlet 11 has an equivalent diameter smaller than or equal to about 20 mm; in particular, smaller than or equal to about 5 mm. Alternatively or in combination, even more advantageously but not limitedly, the through-hole of at least one leading outlet 11 is greater than or equal to about 15 mm, in particular about 10 mm.
It should be noted that in this text, the expression “equivalent diameter” of a through hole must be interpreted as the diameter of a circle having the same area as the through hole.
In use, such size of the outlet 11 allows to increase the speed at which the aforementioned gas G, once heated, is led from the tubular discharge element 10 into the firing chamber 3. This results in a greater linearization of the gas flow G inside the firing chamber 3, which allows for a more uniform temperature within the firing chamber 3 itself. In addition, such size determines an increase in turbulent movements within the tubular discharge element 10 with a consequent facilitation of the heat exchange between the electric heater element and the gas G.
Advantageously but not necessarily (as illustrated in the non-limiting embodiments of
Advantageously but not limitedly (as illustrated in the non-limiting embodiments in
More precisely, (as will be more fully explained below), according to some non-limiting embodiments (such as those illustrated in
Advantageously but not limitedly (as in the embodiments illustrated), the discharge element 10 is substantially coaxial to the tubular casing 6. In detail, the tubular discharge element 10 comprises a longitudinal axis X of symmetry, which advantageously but not limitedly coincides with (i.e. lies on the same straight line as) the longitudinal axis X of symmetry of the tubular casing 6.
According to some advantageous but not limiting embodiments, the tubular discharge element 10 comprises at least one further leading outlet 11′ to lead at least one (respective) further part of the gas G to the outside of the tubular discharge element 10 (in particular, to the outside of the heating assembly 1; even more particularly, in use, towards the firing chamber 3 of the kiln 2).
Even more advantageously (as in the non-limiting embodiments illustrated in
Advantageously, (also) the further 11′ leading outlet, or each of the further leading outlets 11′, has a respective through-hole with an equivalent diameter smaller than or equal to approximately 25 mm (in particular, smaller than or equal to approximately 20 mm). Advantageously, but not limitedly, the further leading outlet 11′ (or each of the further leading outlets 11′) is also arranged at the end portion 14.
According to some non-limiting embodiments, such as those illustrated in
Advantageously, but not necessarily, (as in the embodiments illustrated in
Advantageously but not limitedly, the end portion 12 of the tubular discharge element 11 is configured to couple to the part 13 of the tubular casing 6; in particular, according to some non-limiting embodiments (such as those illustrated in
Advantageously but not necessarily, the tubular discharge element 10 has a circular cross-section, in particular with a constant diameter. In addition, advantageously but not necessarily, the tubular discharge element 10 is made in a single piece, particularly silicon carbide.
Advantageously but not necessarily, (also) the tubular casing 6 has a circular cross-section, in particular with a constant diameter.
According to some advantageous but non-limiting embodiments (such as those illustrated in
According to some advantageous but non-limiting embodiments (such as those illustrated in
The presence of the taper 18 further increases the speed of the gas G flowing out of the tubular discharge element 10, in particular from the outlet 11 and/or 11′ determining a further increase in the turbulent movements within the tubular discharge element 10 and facilitating, therefore, the heat exchange between the electric heater element and the gas G. Furthermore, such taper 18 implies a pressure drop, and therefore a flow rate drop, of the gas G which involves a further advantageous increase in the temperature of the gas G for the same amount of heat produced by the electric heater 5 due to the Joule effect.
In detail, with particular reference to the non-limiting embodiment of
According to alternative non-limiting embodiments such as that illustrated in
According to other non-limiting embodiments such s that illustrated in
According to other advantageous but non-limiting embodiments such as that illustrated in
According to some advantageous but non-limiting embodiments (such as those illustrated in
Advantageously but not limitedly, the leading outlet 11 is arranged on the hollow body 20, even more particularly along the axis X of longitudinal symmetry of the tubular outlet element 10, and is coaxial to the aforementioned leading outlet 11.
Furthermore, advantageously but not limitedly, such leading outlet 11″ has a through-hole with an equivalent diameter smaller than or equal to approximately 60 mm.
According to some non-limiting embodiments such as that shown in
Advantageously in this case, the tubular discharge element 10 is placed between the electric heater 5 and the suction element 21.
Advantageously, but not necessarily, and as illustrated in the non-limiting embodiment in
The suction element 21 is (advantageously but not limitedly) configured to bring, in use (i.e. when installed in the kiln 2), at least part of the waste gases F present outside the heating assembly 1 (in particular, outside the tubular discharge element 10) in the hollow body 20 and has one or more openings 22 arranged between the tubular discharge element 10 and the hollow body 20. The introduction of the waste gases F, already hot, which join the above-mentioned gas G inside the tubular discharge element 10, promotes the return of the gases F towards the kiln walls, as well as the heating of the gas G and the preservation of its speed and impulse towards the centre of the chamber of the kiln 2. In general, the gas turbulence of the fumes in the firing chamber 3 is increased improving the temperature uniformity across the width of firing chamber 3 of the kiln 2 and the heat exchange with the material.
Advantageously but not limitedly, the suction element 21 is configured to create a vacuum between the tubular discharge element 10 and the hollow body 20 so as to bring, in use, at least part of the waste gases F present in the firing chamber 3 into the hollow body 20. The introduction of the waste gases F, already hot, which join the above-mentioned gas G inside the tubular discharge element 10, promotes the heating of the gas G and increases the turbulence thereof.
Advantageously but not limitedly, the openings 22 extend through the suction element 21 (e.g., they have an elongated shape and are arranged longitudinally to the tubular discharge element 10 and the hollow body 20).
According to some non-limiting embodiments (such as the one illustrated in
According to some non-limiting embodiments, the suction element 21 comprises, in particular is, a Venturi tube.
Furthermore, according to some non-limiting embodiments (such as the one illustrated in
Advantageously but not necessarily (and as illustrated in
Advantageously, but not necessarily, the tubular discharge element 10 has a circular cross-section, in particular with a constant diameter.
Advantageously but not necessarily, the hollow body 20 has a circular cross-section, in particular with a constant diameter.
Advantageously, but not necessarily, the suction element 21 has a circular cross-section.
Advantageously, but not necessarily, the suction element 21 has a circular cross-section with a substantially variable diameter.
Advantageously, but not necessarily, the narrowing 23 i.e. the cross-section (
More specifically, advantageously but not necessarily, the narrowing 23, i.e. the cross-section TT (
Still more advantageously but not limitedly, the narrowing 23, i.e. the cross-section TT (
In particular, in this case, advantageously but not limitedly, the narrowing 23 (i.e. the cross-section TT (
The more the diameter of the narrowing 23 decreases, relative to the diameter of the tubular discharge element 10, the more the variation in the speed at which the gas G moves within the hollow body 19 increases. The increase in speed is advantageous both because it allows to let the gas G flow out with a greater speed, and because it increases the turbulence of the gas G within the heating assembly 1, advantageously improving the heat exchange between the gas and the electric heater element.
In the non-limiting embodiment of
In particular, a side surface 28 of the tubular discharge element 10, of the hollow body 20 and of the suction element 21 is (at least) partially without interruption. More specifically, the side surface 28 is without interruption in the sections not interrupted by the openings 22 (see
Advantageously, but not necessarily, such single body (comprising the tubular discharge element 10, the hollow body 20 and the suction element 21) is made in a single piece, in particular of silicon carbide.
Alternatively, advantageously but not necessarily, such a single body (comprising the tubular discharge element 10, the hollow body 20 and the suction element 21) is made by additive manufacturing, in particular 3D printing. Alternatively, this single body is formed by welding the various constituent elements together, i.e. in this case, the tubular discharge element 10, the hollow body 20, and the suction element 21.
According to other non-limiting and non-illustrated embodiments, such a single body (comprising the tubular discharge element 10, the hollow body 20 and the suction element 21) is formed by mechanically coupling by means of fastening systems (e.g. bolts, screws, rivets, etc.) the various constituent elements, i.e., in this case, the tubular discharge element 10, the hollow body 20, and the suction element 21.
According to further non-limiting embodiments, such single body (comprising the tubular discharge element 10, the hollow body 20 and the suction element 21) is formed by means of mould casting techniques.
According to some not illustrated embodiments, the heating assembly 1 comprises a plurality of hollow bodies (similar to the hollow body 20) interspersed with corresponding suction elements (of the type of the suction element 21).
According to some not illustrated embodiments, the heating assembly 1 comprises a high-pressure fan to supply gas G (comprising, in particular, ambient air having at least 21% oxygen) to the electric heater 5. This advantageously allows to compensates for at least part of the pressure losses, and thus flow rate losses, of the gas G which arise as the gas G flows through the tubular casing 6 and the discharge element 10, thus preserving the flow rate thereof.
Referring in particular to
The industrial apparatus 29 comprises a kiln 2 (as described above), in particular a tunnel kiln, having at least one side wall 30 and a roof or vault 31 delimiting a firing chamber 3 having a surface 32 inside the firing chamber 3 and a surface 33 outside the firing chamber 3.
In particular, the kiln 2 is advantageously tunnel-like with two opposite walls 30′ and 30″ forming the side wall 30, between which the ceramic articles T transit, and a roof or vault 31.
The industrial apparatus 29 further comprises a transport system 4 (as described above), in particular horizontal, which (as described above) is adapted to move a plurality of ceramic articles T along a conveying path P within the firing chamber 3 (from an inlet to an outlet of the firing chamber 3).
The transport system 4 may be any type of transport system.
Advantageously (as mentioned above), the transport system 4 comprises a series of rollers made of refractory material, on which the raw ceramic articles T to be fired are placed, preferably in an orderly fashion. More in detail (according to advantageous some but non-limiting embodiments), the transport system 4 comprises a plurality of ceramic rollers (possibly moved at different speeds to differentiate the firing of the articles) that define a conveying plane.
The apparatus 29 further comprises a heating system 34 (partially illustrated in
Advantageously, the heating system 34 comprises at least one heating assembly 1. Even more advantageously, the heating system 34 comprises a plurality of heating assemblies 1 arranged in series along a direction parallel to the conveying path P.
More in detail, with particular reference to
Advantageously, but not limitedly, the firing chamber 3 of the kiln 2 comprises (in particular, is divided into) at least one pre-heating area, one pre-firing area, one firing area and one cooling area arranged (one after the other) along the conveying path P. Advantageously, but not necessarily, the pre-heating area is connected to the pre-firing area and the firing area (without interruption), more specifically in a direct manner (i.e. without the interposition of further areas and/or chambers). Advantageously, the firing area and the cooling area are also, preferably but not necessarily, connected (without interruption), particularly in a direct manner (i.e. without the interposition of further chambers and/or areas).
In detail, within the pre-heating and pre-firing areas, the temperature of the ceramic articles T is gradually increased until a firing temperature of at least about 1100° C. is reached, in particular of at least about 1200° C., which is kept constant throughout the firing area; while within the cooling area, the temperature of the fired base ceramic articles BC exiting the firing area 6 is rapidly reduced.
Advantageously, but not limitedly, at least a part of the mentioned heating assemblies 1 is arranged at the pre-heating area (in particular, also in the pre-firing area) to heat at least the pre-heating area of said firing chamber 3 so as to impose within said pre-heating area a temperature of at least about 1000° C., in particular at least about 1100° C.
Advantageously, but not limitedly, according to some non-limiting and not illustrated embodiments, the heating system 34 of the apparatus 29 also comprises a plurality of electric radiant panels arranged within the firing chamber 3, in particular they are arranged on the surface 32 of the vault or roof 31 and above the surface of a bottom or sole or floor 35 of the firing chamber 3 of the kiln 2. The function of these radiant panels is to impose the above-mentioned firing temperature within the firing area itself. It is thereby possible to make an all-electric firing apparatus 29 for the firing of ceramic articles T, the benefit of which is a substantial reduction in CO2 emissions.
According to some advantageous but non-limiting embodiments, the heating assemblies 1 are arranged (i.e. they are mounted on the walls in the kiln) on several levels within the side wall 30 of the kiln 2; in particular of both the aforementioned side walls 30′, 30″ of the kiln 2.
In detail, advantageously, in the event that the transport system 4 comprises (consists of) ceramic rollers as described above, at least a part of the heating assemblies 1 is arranged below the conveying plane. The presence of the heating assemblies 1 also below the conveying plane enables a more uniform distribution of the heat within the firing chamber 3.
In combination (as illustrated in the non-limiting embodiments shown in
Advantageously, the heating assemblies 1 are arranged (i.e. mounted) on the kiln 2 oriented in a direction that is transverse (i.e. perpendicular) to the advancement direction A (and thus to the conveying path P).
The counter current arrangement (i.e. orthogonal to the advancement direction of the ceramic articles T) of the heating assemblies 1 allows to avoid the risk that the gas jet G flowing out of the heating assembly 1 arrives directly at the ceramic articles T, with the consequent risk of damaging them.
Advantageously, but not necessarily, the/each heating assembly 1 is arranged (i.e. installed) in such a way that at least part of the tubular discharge element 10 protrudes at least partially into the firing chamber 3.
Still in more detail, according to some advantageous but non-limiting embodiments, the tubular discharge element 10 of the (i.e. of each) heating assembly 1 has a length of at least about 900 mm and the heating assembly 1 is installed in such a way that said discharge element 10 protrudes inside the firing chamber 3 by a length of at least about 600 mm.
According to still other advantageous but non-limiting embodiments such as the one illustrated in
Advantageously, but not limitedly, the/each heating assembly 1 is arranged (i.e. installed) so that the electric heater of the (in particular, of each) heating assembly 1 extends at least partially (in particular, totally) through the (in particular, transversely) side wall or roof or vault 31 of the kiln 2 or between the inner and outer surface of the firing chamber 3.
According to some advantageous but non-limiting embodiments (e.g. illustrated in
Alternatively or in combination, advantageously, but not limitedly, in this case (when the heating assembly 1 also comprises the hollow body 20 and the suction element 21 as described above), the heating assembly 1 is installed so that the electric heater 5 extends at least partially (in particular, totally) through (in particular, transversely) the side wall 30 or the roof or vault 31 of the kiln 2 between the inner surface 32 and the outer surface 33; the tubular discharge element 10 extends at least partially (in particular, totally) through (in particular, transversely) the side wall 30 or the roof or vault 31 of the kiln 2 between the inner surface 32 and the outer surface 33; and the hollow body 20 extends substantially completely within the firing chamber 3.
According to some non-limiting and non-illustrated embodiments, advantageously but not necessarily, the heating assembly 1 is installed so that the tubular discharge element 10 protrudes at least partially into the firing chamber 3.
In the graph in
In
This graph was also derived experimentally. Also from this graph it follows that the narrowing of the equivalent diameter of the through-hole of the leading outlet 11 causes the increase of the back pressure of the gases G flowing out of the leading outlet 11, increasing its temperature and the flowing-out speed of the gas G, which becomes more similar to that produced by an architecture already known in the literature with a high-speed gas burner (curves I and II). Furthermore, from the graph in
The apparatus 29 and the heating assembly 1 described above have many advantages.
The main advantage of the apparatus 29 and heating assembly 1 of the present invention lies in the reduction of CO2 emissions and consumption of non-renewable raw materials, resulting in clear environmental benefits.
Furthermore, the use of an electric heater 5 such as the one described above allows for a more precise control of the temperatures within the firing chamber 3 at least in the area having the heating assemblies 1 described above, as well as an increase in safety due to the at least partial overcoming of all safety drawbacks related to combustion.
Compared to the known methods and systems for electrically heating kilns for firing ceramic articles T, the heating assembly 1 of the invention enables ceramic articles T to be heated more effectively and uniformly along their entire cross-section. This enables an optimal firing of ceramic articles up to about 15 mm thick, in particular up to about 10 mm.
Furthermore, with the heating assembly 1 and the apparatus 29 of the invention, the occurrence of fumes inside the firing chamber 3 is limited and therefore also the risk of particulate deposition on the ceramic articles T is reduced, with the consequent reduction in the risk of damaging the articles themselves.
In addition, the heating assembly 1 of the present invention, given its geometry and penetration into the firing chamber 3, may safely be installed in place of a standard gas burner architecture of the kiln 2.
The following aspects of the invention are also provided (alternatively or additionally).
A heating assembly (1) for the firing of ceramic articles (T), which is installable in an industrial kiln (2) comprising a firing chamber (3); the heating assembly (1) comprises:
2. The heating assembly (1) according to aspect 1, wherein: the tubular discharge element (10) comprises a first end portion (12) coupled to a part (13) of said tubular casing (6), a second end portion (14) opposite to the first end portion (12) coupled to said hollow body (20) and a further leading outlet (11) arranged at said second end portion (14) along an axis (X) of longitudinal symmetry of said tubular discharge element (10) for fluidically connecting said tubular discharge element (10) and said hollow body (20); and
the hollow body (20) comprises an end portion (19); and said leading outlet (11″) is arranged at said end portion (19) along said axis (X) of longitudinal symmetry of the tubular discharge element (10).
3. The heating assembly (1) according to aspect 1 or 2, in which the leading outlet (11″) has a through-hole with an equivalent diameter smaller than or equal to approximately 60 mm; in particular, said further leading outlet (11) has an equivalent diameter smaller than approximately 25 mm.
4. The heating assembly (1) according to any one of the preceding aspects, wherein the suction element (21) is configured to create a vacuum between the tubular discharge element (10) and the second hollow body (20) so as to bring, in use, at least part of the waste gases (F) present in the firing chamber (3) into the hollow body (20); and said openings (22) extend through the suction element (21) (e.g. they have an elongated shape and are arranged longitudinally to the tubular discharge element (10) and the second hollow body (20)).
5. The heating assembly (1) according to any one of the preceding aspects, wherein the tubular discharge element (10) is coaxial to said hollow body (20) and the suction element (21) comprises a Venturi tube.
6. The heating assembly (1) according to any one of the preceding aspects, wherein:
7. The heating assembly (1) according to aspect 6, wherein the narrowing (23) has a diameter smaller than one-third of the diameter of the tubular discharge element (10) and the second hollow body (20); in particular, the narrowing (23) has a diameter ranging from about 10 mm (in particular, from about 20 mm; more particularly, from about 25 mm) to about 60 mm (in particular, from about 40 mm; more particularly, to about 35 mm).
8. The heating assembly (1) according to aspect 6 or 7, wherein the tubular discharge element (10) and the second hollow body (20) have a diameter between approximately 30 mm (in particular, approximately 40 mm; more particularly, approximately 50 mm) and approximately 200 mm (in particular, approximately 120 mm; more particularly, approximately 100 mm).
9. An industrial apparatus (29) for the firing of ceramic articles (T) comprising: a tunnel kiln (2) provided with at least one side wall (30) and a roof/vault (31), which at least partially delimit a firing chamber (3) having an inner surface (32) and an outer surface (33); a transport system (4), which is configured to move a plurality of ceramic articles (T) along a conveying path (P) inside the firing chamber (3); and a heating system (34), which is configured to heat said firing chamber (3) so as to fire said plurality of ceramic articles (T) moving through the inside of said firing chamber (3) and obtain ceramic products (PC);
the kiln (2) being characterized in that said heating system (34) comprises at least one heating assembly (1) according to any one of the preceding aspects 1 to 8.
10. The industrial apparatus (29) according to aspect 9, wherein said heating assembly (1) is installed so that said suction element (21) is, at least partially, inside the firing chamber (3).
11. The industrial apparatus (29) according to aspect 9 or 10, wherein said (in particular, each) heating assembly (1) is installed in such a way that said electric heater (5) extends at least partially (in particular, totally) through (in particular, transversely) the side wall (30) or the roof/vault (31) of the kiln (2) between said inner surface (32) and said outer surface (33); said tubular discharge element (10) extends at least partially (in particular, totally) through (in particular, transversely) the side wall (30) or the roof/vault (31) of the kiln (2) between said inner surface (32) and said outer surface (33); and the hollow body (20) extends substantially completely within the firing chamber (3).
12. The industrial apparatus (29) according to any one of aspects 9 to 11, wherein said heating assembly (1) is installed so that the tubular discharge element (10) protrudes at least partially into the firing chamber (3).
13. The industrial apparatus (29) according to any one of aspects 9 to 12, wherein: said heating system (34) comprising a plurality of heating assemblies (1) arranged in series along said conveying path (P); a part of said plurality of said heating assemblies (1) is arranged at said roof/vault (31) of the kiln (2); and each heating assembly (1) of said part of the plurality of the heating assemblies (1) is installed inclined with respect to the vertical and/or with respect to the conveying path (P), in particular by an angle varying between about 0° and about 60° with respect to the vertical and/or by an angle varying between about 0° and about 60° with respect to the conveying path (P).
14. The industrial apparatus (29) according to aspect 13, wherein: said firing chamber (3) of said kiln (2) comprises (in particular, is divided into) at least one pre-heating area, a pre-heating area immediately downstream of the pre-heating area along said determined path (P), a firing area downstream of the pre-heating area along said determined path (P), and at least one cooling area downstream of the firing area; and said plurality of heating assemblies is arranged at least at said pre-heating area (in particular, also in said pre-heating area) to heat at least said pre-heating area of said firing chamber (3) so as to impose a temperature of at least about 1100° C., in particular at least about 1200° C.
15. The industrial apparatus (29) according to any one of the aspects from 9 to 14, wherein: said transport system (4) comprises a series of ceramic rollers arranged one after the other along said conveying path (P) so as to define a conveying plane suited to receive said ceramic articles (T) and move them along said conveying path (P); and at least part of the heating assemblies (1) are arranged under said conveying path.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102021000016334 | Jun 2021 | IT | national |
| 102021000016352 | Jun 2021 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/055733 | 6/21/2022 | WO |
