Electric melting hybrid glass manufacturing furnace for supplying float units

Abstract

The present invention relates to a hybrid glass making furnace (10) for producing glass, which is for feeding a unit for floating glass on a molten metal bath, said hybrid furnace (10) comprising, from upstream to downstream: - an electric melting zone (100) having a cold top (140) and an electrode (110) for melting the vitrifiable mixture, thereby obtaining a glass bath (130); - a refining homogenization zone (200) with a hot top, the refining homogenization zone (200) having a first convection loop (210) and a second convection loop (220); and - a zone (300) for cooling the glass, said zone (300) being formed by an equalization tank (310), traversed by said second convection loop (220) and connected to at least one flow path (400), having the hybrid furnace (10) having at least one tank neck (160), called a first tank neck, having a floor (165) and connecting the electric melting zone (100) to the refining and homogenizing zone (200) of glass, and the hybrid furnace (10) having a "no-return" separator (170) located in the first tank neck (160) and designed to prevent molten glass in the refining and homogenizing zone (200) from returning to the melting zone (100); It is characterized by:

Description

[Technical field]

[0001] The present invention relates to an electric fusion hybrid glass making furnace for supplying a float unit.

[0002] The present invention more particularly relates to an electric melting hybrid glass making furnace for supplying a float unit, which further comprises an electric melting zone having a cold top for melting the vitrifiable mixture, connected via a first tank neck to a refining homogenization zone having a hot top with two glass convection loops, thereby obtaining a suitable amount of high quality glass.

[0003] The hybrid glass making furnace according to the invention is not only capable of delivering high quality glass having less than 0.1 bubbles per liter, but is also capable of supplying such glass at a take-off rate of at least 400 tons per day, thereby feeding a float glass unit over a molten metal bath intended to produce float glass. [Background technology]

[0004] Various designs of furnaces for producing glass are known from the prior art, depending in particular on the final shape of the article to be produced, i.e. glass.

[0005] Thus, different furnace designs are differentiated depending on whether the planned production relates to fiberglass, industrial hollow glass forming, or flat glass.

[0006] One of the industrial challenges in the design of glass furnaces is to be able to obtain glass whose quality requirements depend on the article. In this respect, the production of flat glass is relatively one of the most demanding.

[0007] Produced in very large quantities, flat glass is used in a wide range of applications thanks to its versatility: it is widely used in the electronics (flat screens), architectural and automotive sectors, and it can be processed using various techniques (bending, tempering, etc.), making it the glass on which a whole range of glass articles is based.

[0008] The present invention takes into account quality and quantity issues and is particularly aimed at the production of glass for the industrial formation of such flat glass, which is still called float glass, since flat glass is conventionally obtained by glass float units on a bath of molten metal, typically tin.

[0009] For the production of flat glass, it is expected that the float unit can be supplied with high quality glass, i.e. glass that is as bubble-free as possible, i.e. typically with less than 0.5 bubbles / liter.

[0010] The quality of glass is determined in particular, but not exclusively, by the number of bubbles present in the glass, expressed as "bubbles / liter." The fewer the number of bubbles per liter of glass, the higher its quality is considered to be.

[0011] It should also be remembered that the presence of bubbles (or gaseous defects) in glass is inherent to the glass making process, which generally involves three successive states or stages: melting, refining and homogenization, and thermal conditioning of the glass.

[0012] The presence of bubbles in the glass results from the melting process in which a vitrifiable mixture, also called a "batch" (composition), is melted. The vitrifiable mixture is made of raw materials including, for example, a mixture of sand, limestone (calcium carbonate), soda ash, and dolomite for the production of soda-lime glass (the glass most commonly used to make flat glass), and advantageously, cullet, made of broken glass, is added, thereby facilitating melting.

[0013] The vitrifiable mixture turns into a liquid mass and the least miscible particles, i.e., silicon dioxide or silica (SiO 2 ) is the most abundant, and sodium oxide (Na 2 Even those with little O will melt.

[0014] Sodium carbonate (Na 2 CO 3 ) begins to react with the sand grains at 775°C, producing carbon dioxide (CO 2 ) bubbles into the liquid, increasing its viscosity as carbonates are converted to silicates. Similarly, the conversion of limestone grains to lime and the decomposition of dolomite are also caused by the release of carbon dioxide (CO 2 ) resulting in the release of

[0015] The melting stage is complete when there are no solid particles in the molten glass liquid, which becomes highly viscous and is filled with air and gas bubbles at this stage of the manufacturing process.

[0016] The refining and homogenizing step then makes it possible to remove any gas bubbles present in the molten glass. As is well known, "refining agents" are advantageously used during this stage, that is to say substances in low concentration which, by decomposing at the melting temperature of the bath, provide gases that expand the gas bubbles, thus facilitating their rise to the surface of the glass.

[0017] And the thermal conditioning stage of the manufacturing process makes it possible to reduce the temperature of the glass; because at the start of the forming operation the viscosity of the glass generally needs to be at least 10 times higher than during refining.

[0018] Each of the glass manufacturing steps just described will of course correspond to the furnace construction used to carry them out.

[0019] Typically, this type of glass furnace includes a melting zone where the glass batch is melted to form a glass bath, then a refining and homogenizing zone where the glass is degassed, and finally, a thermal conditioning zone where the glass is cooled to its forming temperature, which is much lower than the temperatures the glass experiences during its production.

[0020] From the above mentioned glass production process, the melting stage does not emit any carbon dioxide (CO), one of the main greenhouse gases responsible for climate change. 2 ) is seen to be emitted.

[0021] For this reason, these direct carbon dioxide (CO 2 ) emissions, and indirect carbon dioxide (CO ) emissions associated with the raw materials used in the vitrifiable mixture. 2 Efforts are underway to use a higher proportion of cullet to reduce emissions.

[0022] In fact, apart from the industrial challenge of producing high quality glass and high productivity at the lowest possible costs of furnace construction and operation, one of the other main current challenges that the glass industry has to face is ecology, i.e. the carbon footprint (or CO2) of the process of producing glass. 2 The need to find solutions to reduce the global footprint of renewable energy.

[0023] To achieve carbon neutrality, a global approach to processes that seeks to act in multiple ways to reduce both direct and indirect emissions during production, as well as upstream and downstream emissions in the value chain, such as those associated with upstream material transport and downstream goods transport, is preferred.

[0024] These methods therefore include improving the design and material composition of articles, the energy efficiency of industrial processes, using renewable and decarbonized energy, working with material suppliers and transporters to reduce their emissions, and finally, exploring technologies to capture and sequester residual emissions.

[0025] In addition to the direct emissions inherent in the glass production process mentioned above, the type of energy used represents the largest proportion of the carbon footprint of the glass production process, especially for the high temperature melting stage (above 1500° C.); since it generally requires fossil fuels, most often natural gas, or petroleum commodities such as heavy oil.

[0026] As a result, research into new furnace designs is focused on meeting industrial challenges related to glass quality as well as reducing direct and indirect carbon dioxide (CO 2 ) From an emissions perspective, the carbon footprint of the glass production process must also be reduced, particularly by reducing the use of fossil fuels.

[0027] Glass production takes place in furnaces that have continually evolved from the first pot (or crucible) furnaces, through the Siemens furnaces, generally considered the ancestors of today's large continuous melting glass furnaces, to the cross-fired furnaces capable of producing up to 1,200 tons of float glass per day.

[0028] Thus, the choice of energy used for melting leads to two common large furnace designs for glass production: flame furnaces and electric furnaces.

[0029] According to a first design, flame furnaces generally use fossil fuels, in particular natural gas, in the burners; the thermal energy is thus transferred to the glass by heat exchange between the flame and the surface of the glass bath.

[0030] The cross-fire furnace mentioned above is an example of a furnace according to this first design, widely used to supply molten glass to float units intended to produce flat glass.

[0031] According to a second design, the electric furnace is one in which the thermal energy is generated by the Joule effect within the mass of molten glass.

[0032] Indeed, glasses, which are insulating materials at room temperature, become electrically conductive at high temperatures, thereby allowing them to be heated by the Joule effect within the glass melt.

[0033] However, electric furnaces are used, for example, for the production of special glasses, such as opal glasses containing fluorine or lead crystals, or generally for the manufacture of glass fibres for thermal insulation.

[0034] In fact, it is generally accepted by those skilled in the art that such electric furnaces are not capable of supplying glass in sufficient quantities or quality (bearing in mind less than 0.5 bubbles per liter) to float glass units on molten metal baths intended for the production of flat glass.

[0035] Prior art electric furnaces known to the applicant are at best capable of delivering glass having a few hundred bubbles per litre, more usually several thousand bubbles, at a take-off rate of 200-250 tonnes per day, which may be suitable for forming hollow glass, typically bottles, etc., but is by no means suitable for producing flat glass and thus feeding a float unit.

[0036] That is why today flame furnaces (such as cross-fire furnaces) remain the only furnaces capable of supplying such float glass units.

[0037] However, flame furnaces rely on the use of fossil fuels, essentially natural gas, and therefore their carbon footprint is dominated by carbon dioxide (CO 2 ) emissions, and thus is hardly compatible with the objective of reducing the carbon footprint of the glass production process.

[0038] To conclude the description of the prior art furnace designs for glass production, reference is made to a "third design" of furnaces, which is particularly suited to the use of carbon dioxide (CO 2 ) have been developed in recent years to address the ecological challenge of reducing emissions.

[0039] This third furnace design is based on a flame furnace, but uses electric booster heating, specifically to momentarily increase furnace output or improve glass quality.

[0040] Such furnaces are therefore also called "electrically boosted flame furnaces".

[0041] Thus, this third design of reactor combines multiple energy sources, fossil fuels and electricity respectively, and is therefore also called a "hybrid" reactor.

[0042] The addition of electric booster heating makes it possible to increase the melting capacity of the flame furnace, which is limited by the heat transfer that occurs between the flame and the surface of the glass bath.

[0043] However, since the operation of such hybrid furnaces is always primarily based on the use of fossil fuels, typically gas, the ultimate impact in improving the carbon footprint of the glass production process remains limited.

[0044] In fact, the impact is proportional, since electricity is only used as a booster. Moreover, in order to effectively improve the carbon footprint, the electricity used still needs to be so-called "green" electricity, i.e. electricity generated from renewable and decarbonized energy sources. Summary of the Invention [Problem to be solved by the invention]

[0045] The object of the present invention is in particular to reduce the amount of carbon dioxide (CO 2 The objective of the present invention is to propose a new design of glass production furnace capable of delivering high quality glass and feeding it to a float glass unit for the production of flat glass, at an energy consumption level that allows obtaining a significant reduction in CO2 emissions. [Means for solving the problem]

[0046] For this purpose, the invention proposes a hybrid glass production furnace for feeding a unit for floating glass on a molten metal bath, said hybrid furnace comprising, from upstream to downstream: - an electric melting zone with a cold top, having electrodes for melting the vitrifiable mixture, thereby obtaining a glass bath; - a refining and homogenization zone having a hot top, the refining and homogenization zone having a first convection loop and a second convection loop; and - a zone for cooling the glass, the zone being formed by an equalization tank, traversed by said second convection loop and connected to at least one flow path, having The hybrid furnace is characterized in that it has at least one tank neck, called the first tank neck, which has a floor and connects an electric melting zone to a glass refining and homogenizing zone, and that it has a "no-return" separation device, which is disposed in the first tank neck and is designed to prevent molten glass in the refining and homogenizing zone from returning to the melting zone.

[0047] Advantageously, said first tank neck of the hybrid furnace is combined with a separation device and participates in the temperature control of the glass by making it possible to ensure the cooling of the glass flowing from the electric melting zone to the glass refining and homogenization zone, thereby obtaining control of the first and second convection loops, with the final benefit of producing a desired quantity of high quality glass.

[0048] Advantageously, the hybrid furnace comprises glass cooling means capable of selectively cooling the glass in the first tank neck. Preferably, the hybrid furnace comprises an air circulation cooling device.

[0049] Advantageously, the means for cooling the glass are capable of ensuring a variable cooling, which is adjustable and in particular determined as a function of the temperature of the glass.

[0050] The hybrid furnace according to the invention makes it possible to combine, on the one hand, the melting of a high-performance vitrifiable mixture in the melting zone and, on the other hand, the control of the temperature of the glass introduced into the refining and homogenizing zone, in particular to obtain there glass flows having a first and a second convection loop, respectively, whereby high quality glass is in particular obtained.

[0051] In fact, the separator limits the amount of molten glass flowing downstream from the melting zone and thus promotes cooling of the glass in the first tank neck, which is why there is a synergistic effect between the separator and the first tank neck.

[0052] Additionally, the separation device also prevents glass from returning from the refining and homogenizing zone to the melting zone and into the first tank neck, thereby allowing the molten glass to be cooled in the first tank neck and refined in the refining and homogenizing zone having a first convection loop and a second convection loop.

[0053] Advantageously, the separation device ensuring the function of preventing the glass from returning to the electromelting zone comprises, depending on the embodiment, a dam and / or at least one plateau in the floor of the first tank neck.

[0054] According to the invention, the general design of a hybrid furnace with an electric melting zone and a refining zone with two convection loops, together with the first tank neck and the separation device connecting them, in other words the combination, not only makes it possible to obtain high quality glass with less than 0.1 bubbles per liter, but also makes it possible to deliver this amount of glass at a withdrawal rate of more than 400 tons per day, so as to be able to feed, in particular, a float unit.

[0055] Thus, the hybrid furnace according to the invention is capable of feeding glass to a forming zone consisting of a float glass unit on a molten metal bath, intended for the production of flat glass.

[0056] Advantageously, and contrary to the assumptions of those skilled in the art, the hybrid furnace according to the present invention ultimately makes it possible to combine high quality glass and large quantities of glass by doing so using a cold-top electric melting zone (no longer a flame melting zone).

[0057] In the present invention, electricity accounts for more than 60%, or even more than 80%, or even more, of the total energy used in the glass making process in the hybrid furnace.

[0058] The furnace according to the present invention is said to be a "hybrid" in analogy with the third furnace design described above, and thus the term "hybrid" is used to describe it as a result of using two different energy sources, electrical energy and fuel energy, respectively.

[0059] However, the analogy with the present invention does not go beyond this; electrical energy is the only energy source used to melt the glass as it is produced, and therefore fuel energy, fossil fuels or the like is used in the furnace only for the refining and homogenization of the glass.

[0060] Advantageously, the hybrid furnace according to the invention combines, on the one hand, an electric melting zone with a cold top and, on the other hand, a flame-based, i.e. combustion-based, preferably electrically boosted, glass refining and homogenization zone, said melting and refining zones being separated by a so-called "non-return" separation device that directs the glass away from the melting zone.

[0061] Thanks to such a combination, in particular the devices for separation and temperature control of the glass entering the refining and homogenization zone, the hybrid furnace according to the invention makes it possible to obtain high-quality glass, i.e. glass containing less than 0.1 bubbles per liter, while delivering it in large quantities, which can then be advantageously fed to a float glass unit intended for the production of flat glass.

[0062] The present invention therefore goes against the assumptions of those skilled in the art who would not have thought that an electric melting furnace would even make it possible to obtain such high quality glass in such quantities.

[0063] In the present invention, high quality glass is obtained in particular thanks to the refining and homogenization steps carried out after the electric melting step, said steps being advantageously controlled by the cooling of the glass made possible by the first tank neck, this cooling participating in obtaining two convection loops in controlling the directionality of the glass.

[0064] Advantageously, high quality glass is also obtained by a separation device, which is arranged in the first tank neck of the hybrid furnace and configured to prevent return of molten glass from the refining homogenization zone to the melting zone.

[0065] Thanks to the separating device, the flow of glass in the first tank neck is a "piston" flow.

[0066] Advantageously, the separation device is formed by a dam and / or a raised part in the floor of the first tank neck, which, each alone or together, can prevent the molten glass from returning from the refining homogenization zone to the electric melting zone of the hybrid furnace according to the invention.

[0067] In the hybrid furnace according to the invention, due to the separation device described above, no convection loop or glass recirculation loop extends from the refining and homogenizing zone to the melting zone.

[0068] In comparison, the submerged throats connecting the melting zone and the refining zone cannot ensure such a function of preventing glass from returning inside the furnace: in fact, a return flow of glass exists in such submerged throats, in particular due to material wear.

[0069] In addition, since the glass flowing in the immersion throat does not come into contact with the atmosphere, it cannot be cooled in a controlled and variable manner on the surface, particularly by air circulation cooling devices.

[0070] In comparison to a submerged throat, which is structurally restricted in cross section, the first tank neck also allows glass flow at a withdrawal rate compatible with feeding the float unit.

[0071] According to the invention, the step of refining and homogenizing the glass is advantageously carried out on glass with little or no unmelted portions, thanks to a "no-return" separation device which makes it possible to increase the residence time of the glass in the electric melting zone in particular.

[0072] The hybrid furnace according to the invention does not consist of a juxtaposition but of a combination of features; since there is an interaction between the technical features, and in particular a synergy between the electric melting zone and the refining and homogenizing zone with two convection loops, thanks to the first tank neck and associated separation devices, which respectively make it possible for the glass to be cooled and to prevent it from returning to the melting zone.

[0073] Thanks to the first tank neck and the separating device, the temperature of the glass can be separately and precisely controlled in the electric melting zone on the one hand and in the refining and homogenizing zone on the other hand.

[0074] Preferably, the length of the first tank neck is configured to obtain cooling that reduces the temperature of the glass that is intended to subsequently flow into the refining and homogenizing zone.

[0075] Indeed, the molten glass obtained by electric melting generally has a relatively high temperature, especially compared to flame melting.

[0076] As an example, the temperature of the glass in the melting zone may be about 1450°C, while the desired temperature of the glass in the downstream portion of the first tank neck may be relatively within about 1300°C to 1350°C.

[0077] Advantageously, the hybrid furnace comprises glass cooling means arranged in the first tank neck, by means of which the glass can be selectively cooled, i.e. the cooling can be controlled to actively regulate the glass temperature.

[0078] Preferably, the cooling means are formed by at least one air circulation cooling device, whereby air is introduced into the atmosphere of the first tank neck so as to come into contact with and be extracted from the surface of the glass bath, thereby removing the heat (calories) transferred by the glass to the air.

[0079] Alternatively, the cooling means is immersed in the glass flowing from upstream to downstream through the first tank neck, thereby enabling its cooling.

[0080] Such cooling means immersed in the glass are formed, for example, by a dam, which forms all or part of the separation device and is cooled by a cooling circuit with a heat transfer fluid, in particular a circuit of the "water jacket" type.

[0081] According to another embodiment, the cooling means are formed by vertical studs, which are placed in the first tank neck and immersed in the glass and are cooled by a cooling circuit with a heat transfer fluid, thereby removing the heat transferred by the glass.

[0082] According to yet another embodiment, the cooling means can cool the structure of the first tank neck which is in contact with the glass, the cooling being performed from outside the structure of the first tank neck.

[0083] Of course, the cooling means associated with the first tank neck according to the various examples just given can be implemented alone or in combination.

[0084] Advantageously, the means for cooling the glass associated with the first tank neck allows for selective control of the temperature of the glass, which is likely to vary, particularly when the withdrawal rate varies, since an increase in the withdrawal rate causes an increase in the temperature of the glass.

[0085] In comparison to such means for cooling the glass associated with the first tank neck, such variable cooling of the glass would not be possible with the immersion throat.

[0086] Advantageously, the hybrid furnace according to the invention employs electrical energy for melting the vitrifiable mixture and relies on the increasing availability of "green" electricity, e.g. obtained from wind energy, solar energy, etc., rather than from fossil fuels such as coal or oil.

[0087] Advantageously, the fuel energy used in the burners of the refining and homogenizing zone is not a fossil fuel, such as natural gas, but another equivalent fuel energy, preferably hydrogen, or alternatively biomethane.

[0088] As a result, the hybrid furnace according to the invention is able to address not only the issues of high glass quality and withdrawal speed respectively required to feed the float unit, but also environmental issues, thereby making it possible to reduce the carbon footprint of the glass production process.

[0089] Other characteristics of the furnace according to the invention are: - the separating device has a dam which is intended to be partially immersed in the glass bath; the separation device consists only of a dam capable of preventing the molten glass from returning from the refining and homogenizing zone to the melting zone, said dam being preferably located at the upstream end of the first tank neck; - the separation device has at least one elevation in the floor of the first tank neck; -- the separation device consists only of a floor elevation capable of preventing the molten glass from returning from the refining homogenization zone to the melting zone; -- the separating device has at least one elevation in the dam and / or floor, ensuring the function of preventing the glass from returning to the melting zone; -- the separating device, which ensures the function of preventing the glass from returning to the melting zone, has a dam associated with said at least one plateau of the floor; - the at least one ridge of the floor has, from upstream to downstream, at least one ascending portion, a top portion, and a descending portion; - The dam is placed in the first tank neck above the top part of the floor plateau; - at least one of the ascending and descending portions of the at least one floor pedestal is inclined with respect to the horizontal and / or has a top portion; - the at least one pedestal has a maximum height that determines, in whole or in part, a passageway portion of the molten glass within the first tank neck; - the dam is mounted vertically movably to allow adjustment of its immersion depth in the glass bath; --the dam, alone or in combination with said at least one plateau, determines a portion of the passage of the molten glass, which can vary as a function of adjusting the depth of said dam; - the dam is removable, i.e. dismantlable, thereby allowing its replacement, especially when worn, and facilitating the maintenance of the furnace; the hybrid furnace has at least one atmosphere separation means, such as a vertical partition, which allows to separate the atmosphere from the electric melting zone with the cold top and the atmosphere of the refining and homogenizing zone with the hot top; - the hybrid furnace has a blocking means, which is arranged at the upstream end of the first tank neck and is capable of holding the vitrifiable mixture layer in the electric melting zone, thereby preventing said vitrifiable mixture present on the surface of the glass bath from penetrating into the first tank neck; - the means for blocking the vitrifiable mixture layer is formed by a dam; - the blocking means is formed by a separating means, the free end of which extends to the surface of the bath or is immersed in the glass bath; - the blocking means is distinct from said separating means, said blocking means being attached to the separating means or being separate from the separating means; - the hybrid furnace has glass cooling means, in particular at least one air circulation cooling device, capable of cooling the glass in the first tank neck; --the hybrid furnace has a charging zone, the charging device being arranged to introduce said vitrifiable mixture into the electric melting zone; --the charging device is configured to deposit the vitrifiable mixture over the entire surface of the glass bath, thereby forming a barrier layer between the glass bath and the top of the melting zone; - an electrode is placed on the surface, whereby it is immersed in the vitrifiable mixture, said immersion electrode preferably extending vertically; - an electrode is placed through the floor of the melting zone, thereby immersed in the vitrifiable mixture, said raised electrode preferably extending vertically; -- Hybrid furnaces have plunge electrodes and / or riser electrodes; the electric melting zone advantageously has a low-convection zone, called the buffer zone, located between the free end of the immersed electrode and the floor of the melting zone; - the melt zone is configured to have a depth, thereby obtaining said low-convection buffer zone, preferably the depth is greater than 600 mm, even more preferably greater than 800 mm; - the first convection loop and the second convection loop are separated by a loop inversion zone, determined by a hot spot or source, corresponding to the hottest point on the glass; - the refining homogenization zone has at least one burner, which is positioned to obtain said hot spot that determines said loop reversal zone; - the hybrid reactor has a barrier arranged within said loop reversal zone; --the hybrid furnace also includes a bed depth change, preferably at least one plateau or level change, relative to the surface of the glass in the refining and homogenizing zone, said depth change being located in the section including the first convection loop and / or in the section including the second convection loop; - the hybrid furnace has regulating means, such as electric boosts and / or bubblers, which are arranged in the refining and homogenizing zone and make it possible to regulate the convection of said loop, thereby facilitating the operation of the glass production; - the equalizing tank of the cooling zone has, from upstream to downstream, a tank neck, called the second tank neck, and a working end; after the equalization tank, no return flow occurs in the channel intended to supply high-quality glass to the forming zone with said float unit; in other words, the flow of glass in the channel is of the "piston" type; the hybrid furnace is configured to supply glass to said float glass unit intended to produce flat glass at a take-off rate of at least 400 tonnes per day, preferably 600-900 tonnes per day or even 1000 tonnes per day or more, said high quality glass having less than 0.1 bubbles per liter, preferably less than 0.05 bubbles per liter.

[0090] The invention further proposes an assembly for producing flat glass, comprising a hybrid glass production furnace and a float glass unit on a molten metal bath, which is arranged downstream and is fed with glass by said furnace through at least one flow path.

[0091] Further features and advantages of the present invention will become apparent from the following detailed description, for the understanding of which reference should be made to the accompanying drawings, in which: [Brief description of the drawings]

[0092] [Figure 1]FIG. 1 is a side view showing a hybrid glass production furnace according to a first embodiment of the present invention, having an electric melting zone with a cold top connected by a first tank neck to a refining homogenization zone with a hot top having a first convection loop and a second convection loop, and a cooling zone traversed by said second convection loop, and further illustrating a dam forming a “no-return” separation device located in said first tank neck.

[0093] [Diagram 2] FIG. 2 is a top view of the furnace according to FIG. 1, showing the electric melting zone connected by a first tank neck, in which a dam is arranged and designed to prevent molten glass from returning from the refining homogenization zone to the electric melting zone;

[0094] [Diagram 3] FIG. 3 is a side view, similar to FIG. 1, of a hybrid furnace according to a second embodiment of the invention, in which the separation device is formed by a dam and at least one plateau in the floor of the first tank neck, showing the dam associated with said plateau, each configured to prevent the molten glass from returning from the refining homogenization zone to the electric melting zone of the furnace;

[0095] [Figure 4] FIG. 4 is a top view, similar to FIG. 2, showing the hybrid furnace according to FIG. 3, showing a preferably movable dam, which is associated with a floor elevation in the first tank neck connecting the melting zone to the refining and homogenizing zone.

[0096] [Diagram 5]FIG. 5 is a side view, similar to FIGS. 1 and 3, showing a hybrid furnace according to a third embodiment of the invention, in which the separation device is formed only by a pedestal in the floor of the first tank neck, thus illustrating a pedestal without a dam, the pedestal having a greater height than in the second embodiment and configured to prevent the return of the molten glass.

[0097] [Figure 6] FIG. 6 shows a side view in detail of a part of the hybrid furnace according to FIG. 5, showing a variant embodiment of the elevation of the floor of the first tank neck with a descending portion forming a sloping surface, which makes it possible to ensure a gradual change in the depth of the molten glass towards the refining and homogenization zone. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0098] In the remainder of this specification, the terms longitudinal, vertical and transverse will be used without limitation with respect to the axis system (L, V, T) shown in Figures 1-6.

[0099] The terms "upstream" and "downstream" will also be used, without limitation, when referring to the longitudinal direction, "upper" and "lower", or "top" and "bottom" when referring to the vertical direction, and finally "left" and "right" when referring to the transverse direction.

[0100] As used herein, the terms "upstream" and "downstream" correspond to the direction of glass flow within the furnace, with the glass flowing from upstream to downstream along the central longitudinal axis A-A' (upstream from A, downstream from A') of the hybrid furnace, as shown in Figures 2 and 4.

[0101] Furthermore, the term "loop" is used herein in reference to the recirculation of glass within a furnace, as is well known to those skilled in the art, similar to the concepts of a "cold top" and a "hot top" of a glass making furnace.

[0102] 1 and 2 are side and top views, respectively (not to scale), of a hybrid glass making furnace 10 illustrating a first embodiment of the present invention.

[0103] As indicated above, in analogy with the third furnace design described above, the term "hybrid" is used herein to refer to the furnace according to the invention because of the use of two different energy sources, electrical energy and fuel energy, respectively, during the glass production process in the furnace.

[0104] However, the analogy with the present invention does not go beyond this; since, on the one hand, electrical energy (constituting the first source) is the only energy source used to obtain the melting of the glass, and, on the other hand, fuel energy of fossil or equivalent type (constituting the second source) is used only for the refining and homogenization of the glass.

[0105] The hybrid furnace 10 according to the invention is intended in particular to feed a float glass unit on a bath of molten metal, typically tin, for the production of flat glass.

[0106] As shown in Figures 1 and 2, the hybrid furnace 10 has, successively from upstream to downstream along the longitudinal central axis A-A' of the furnace, at least one electric melting zone 100, a refining homogenization zone 200, and a glass cooling zone 300.

[0107] According to a first feature of the hybrid furnace 10 according to the invention, the melting zone 100 of the hybrid furnace 10 is electric.

[0108] Advantageously, the electric melting zone 100 is of the "cold top" type.

[0109] Advantageously, the process of melting the glass is obtained by using only electrical energy in the production of the glass, as compared to prior art hybrid furnaces, where the melting process is obtained by fuel energy and electrical energy as a booster.

[0110] The electric melting zone 100 has electrodes 110 for melting a vitrifiable mixture (or “batch”) of raw materials and cullet, thereby obtaining a glass bath 130 .

[0111] In a known manner, cullet consists of glass fragments obtained by recycling glass, which are then crushed and washed before being added to the raw materials, thereby regenerating glass.

[0112] Advantageously, the cullet promotes melting, i.e., the transformation of the vitrifiable glass mixture by melting.

[0113] Additionally, cullet makes it possible to upgrade the glass used by recycling it (glass is infinitely recyclable), thus reducing the amount of raw materials needed to manufacture glass and helping to reduce the carbon footprint of the glass production process.

[0114] The hybrid furnace 10 has a charging zone 120 in which is arranged a charging device 12 (also called a batch charger) intended for introducing the vitrifiable mixture into the electric melting zone 100, said charging device 12 being indicated diagrammatically by an arrow in FIG. 1 .

[0115] Advantageously, the charging device 12 is configured to deposit the vitrifiable mixture over the entire surface of the glass bath 130, thereby forming a barrier layer 112 between the glass bath 130 and the top 140 of the electric melting zone 100, which is why the latter is called the "cold top".

[0116] Preferably, the glass bath 130 is uniformly covered with a layer 112 of vitrifiable mixture, for example 10-40 cm thick, under which complex chemical reactions take place, which lead to obtaining molten glass, as described in the introduction to this application.

[0117] In the cold-top electric melting zone 100, the power dissipated around the electrode 110 creates, in particular, a high-convection zone 132, which has a very strong upward flow that provides the necessary calories, especially at the interface between the cast iron and the vitrifiable mixture that forms the vitrifiable mixture layer 112.

[0118] Prior art glass production processes use carbon dioxide (CO 2 Besides the carbon dioxide emissions, the decomposition of the raw materials and the use of fossil energy as fuel for the melting process are also responsible for polluting emissions consisting essentially of nitrogen oxides (NOx), sulfur oxides (SOx), halogens and dust.

[0119] Advantageously, there is no combustion (flame) in the cold top electric melting zone 100 of the hybrid furnace 10 according to the invention, which results in relatively very low NOx and SOx pollution rates.

[0120] In addition, carbon dioxide (CO 2 ), the vitrifiable mixture layer 112 present on the surface of the bath 130 advantageously makes it possible to capture, by condensation or by chemical reaction, vapors which, depending on their composition, may be toxic and which are released by the molten glass.

[0121] Advantageously, the electrode 110 is placed on the surface so that it is immersed in the glass bath 130 through the layer 112 covering the surface of the bath 130 as shown in FIG.

[0122] Preferably, the dive electrodes 110 extend vertically. Alternatively, the dive electrodes 110 extend obliquely, i.e., are inclined at an angle to the vertical.

[0123] Alternatively, the electrode 110 is positioned through the floor 150 of the electric melting zone 100, thereby immersed in the bath 130, with the rising electrode (as opposed to a diving electrode) preferably extending vertically, alternatively at an angle.

[0124] Compared to electrodes placed through the floor 150, the diving electrodes 110 also allow for easier control of their wear state and provide dissipation of electrical energy, which is advantageously closer to the melt interface from the layer 112 of vitrifiable mixture.

[0125] Advantageously, the diving electrode 110 makes it possible to preserve the floor 150 of the electromelt zone 100 without an opening, as compared to a rising electrode.

[0126] Preferably, the floor 150 of the electromelting zone 100 is flat, as shown in FIG.

[0127] Alternatively, the floor 150 may include at least one variation in depth relative to the surface of the bath of glass 130, said variation including at least one plateau and / or at least one change in level.

[0128] Preferably, the molten electrodes 110 are evenly distributed within the bath 130. Furthermore, the number of electrodes 110 shown herein, nine, in Figures 1 and 2, is merely exemplary and therefore in no way limiting.

[0129] Alternatively, the electromelt zone 100 may cumulatively include a plunge electrode and a riser electrode.

[0130] According to another alternative arrangement, the electrode 110 penetrates at least one side wall that defines the electromelting zone 100, the electrode 110 then extending horizontally and / or obliquely.

[0131] Advantageously, the electrode 110 is made of molybdenum, a refractory metal that can withstand temperatures of 1700° C. and is particularly suitable for melting glass using the Joule effect; since glass only becomes conductive at high temperatures.

[0132] Advantageously, the electromelting zone 100 has a zone of low convection, called the buffer zone 134 , which is located between the free end of the plunge electrode 110 and the floor 150 .

[0133] The electromelt zone 100 is therefore configured to exhibit a depth (P) below the plunge electrode 110 determined to provide such a low-convection buffer zone 134 .

[0134] Preferably, the depth (P) between the free end of the plunge electrode 110 and the floor 150 is greater than 600 mm, preferably greater than 800 mm.

[0135] Such low convection buffer zones 134 constitute another reason to prefer diving electrodes 110 over rising electrodes that penetrate the floor 150 .

[0136] Advantageously, the presence of low-convection buffer zone 134 contributes directly to obtaining high quality glass by promoting a relatively long residence time of the glass within melting zone 100 .

[0137] Advantageously, the electric melting zone 100 and the glass refining and homogenizing zone 200 are connected to each other by a first tank neck 160, ie a zone of reduced width, as shown by FIG.

[0138] Advantageously, said first tank neck 160 of the hybrid furnace makes it possible to ensure the cooling of the glass as it flows from the electric melting zone 100 to the zone 200 of refining and homogenizing the glass.

[0139] The cooling of the glass will be more significant; because the first tank neck will have a large length, the glass coming from the melting zone 100 will naturally cool as it flows from upstream to downstream through the first tank neck 160.

[0140] Advantageously, the hybrid furnace 10 comprises glass cooling means 500 capable of selectively cooling the glass in the first tank neck 160 .

[0141] In addition to the cooling of the glass during its flow through the first tank neck 160 connecting the melting zone 100 to the refining zone 200, such cooling means 500 make it possible to further increase the cooling and in particular to vary this cooling, thanks to which an adjustment of the temperature of the glass is then advantageously obtained.

[0142] Preferably, the means 500 for cooling the glass in the first tank neck 160 comprises at least one air circulation cooling device 510 .

[0143] Exemplary embodiments of the cooling device 510 will be described below as more particularly shown diagrammatically in Figures 3 and 4 showing a second embodiment, and in Figures 5 and 6 showing a third embodiment and variant, respectively, so that reference will advantageously be made to said figures.

[0144] Such an air cooling device 510 for glass comprises, for example, at least intake means 512 for introducing cooling air into the atmosphere of said first tank neck 160 of the hybrid furnace 10 .

[0145] Preferably, the device 510 for cooling the glass comprises exhaust means 514 arranged in the first tank neck 160 for exhausting the hot air and ensuring its renewal by fresh cooling air.

[0146] Alternatively, the exhaust means are formed by extraction means (not shown), located downstream of the first tank neck 160 and intended to extract the fumes, and advantageously the hot air is exhausted together with the fumes by said extraction means, without the hybrid furnace 10 having to be equipped with additional means.

[0147] The intake means 512 and the air exhaust means 514 of the glass cooling device 510 are formed, for example, by one or more openings emerging in a side wall supporting the top of the first tank neck 160 .

[0148] As shown diagrammatically in FIG. 3 and above, the at least one intake opening and the at least one exhaust opening are, for example, positioned opposite each other in the longitudinal direction, with the one or more intake openings being located in an upstream portion of the first tank neck 160, while the one or more exhaust openings are located in a downstream portion of the first tank neck 160.

[0149] The intake means 512 and the air discharge means 514 are arranged, for example, on both sides of the first tank neck 160 in the transverse direction, or alternatively on only one side of the first tank neck 160 .

[0150] Advantageously, the temperature of the cooling air introduced into the first tank neck 160 is lower than the temperature of the hot air located inside said first tank neck 160, and the circulated cooling air forms a heat transfer fluid.

[0151] Preferably, the cooling air used is ambient air taken from outside the hybrid furnace 10 or even outside the building enclosure in which said hybrid furnace 10 is installed, to supply the float unit.

[0152] Advantageously, the temperature of the atmospheric air used is controlled, whereby it can be regulated, for example the air can be pre-cooled or reheated before introduction to control its temperature.

[0153] Cooling of the glass is achieved primarily by convection; the introduced cooling air heats up as it contacts the surface of the glass and is then removed along with the heat (calories) transferred by the glass.

[0154] Advantageously, the circulation of air is controllable by air blowing means (not shown), such as a fan, associated with said intake means and / or exhaust means and which can be controlled to vary the flow rate of circulating air.

[0155] According to another embodiment, the means 500 for cooling the glass are immersed in the glass flowing from upstream to downstream through said first tank neck 160, thereby enabling its cooling.

[0156] Such cooling means are for example formed by vertical studs immersed in the glass which are cooled by a cooling circuit with a heat transfer fluid, thereby dissipating the heat transferred by the glass to the studs.

[0157] According to yet another embodiment, the cooling means 500 can cool the structure of the first tank neck 160 that is in contact with the glass, the cooling being performed from outside the structure of the first tank neck 160 .

[0158] Of course, the cooling means 500 associated with the first tank neck 160, such as those according to the various embodiments previously described, can be implemented alone or in combination.

[0159] Advantageously, the means 500 for cooling the glass associated with the first tank neck 160 allows for selective control of the temperature of the glass, which is likely to change, especially when the removal rate changes; because an increase in the removal rate causes the temperature of the glass to increase.

[0160] FIG. 2 illustrates an exemplary embodiment of a first tank neck 160 that connects the electric melting zone 100 to the refining and homogenizing zone 200 .

[0161] The passage from the electric melting zone 100 to the first tank neck 160 involves an abrupt narrowing in width and cross section of the glass passage, for example by walls 162 and 163 which here form an angle of 90° with the central longitudinal axis A-A' of the furnace.

[0162] The passage from the first tank neck 160 to the zone 200 for refining and homogenizing the glass is accompanied by a sudden expansion of the cross section of the glass passage, for example by walls 262 and 263, which here form an angle of 90° with the central longitudinal axis A-A' of the furnace.

[0163] Alternatively, the angle at the inlet of the first tank neck 160 can have a value greater than 90°, thereby causing the narrowing in width to be relatively gradual rather than abrupt; similarly, the value of the angle at the outlet of the first tank neck 160 can be selected so as to cause the widening along the furnace longitudinal central axis A-A' to be relatively gradual rather than abrupt.

[0164] Advantageously, the molten glass flowing from upstream to downstream through the first tank neck 160 is taken from the lower portion, i.e., the bottom, of the electric melting zone 100, where the glass is relatively "cooler" than that in the high convection zone 132 located between the electrodes 110.

[0165] In this first embodiment, the first tank neck 160 has a floor (not referenced), which is preferably flat, and which extends horizontally in continuation of the flat floor 150 of the electric melting zone 100.

[0166] In accordance with the present invention, the hybrid furnace 10 includes a “no-return” separator 170 located in the first tank neck 160 and configured to prevent molten glass from returning from the refining and homogenizing zone 200 to the melting zone 100.

[0167] The separation device 170 according to the first embodiment of the hybrid reactor 10 illustrated by FIGS. 1 and 2 will be described in more detail later.

[0168] According to a second feature of the hybrid furnace 10 according to the invention, in contrast to the cold-top electric melting zone 100, the refining and homogenizing zone 200 of the hybrid furnace 10 is of the "hot-top" type.

[0169] The refining and homogenizing zone 200 of the hybrid furnace 10 is configured to remove bubbles (or gaseous defects) present in the molten glass coming from the electric melting zone 100, thereby obtaining high quality glass, which in particular allows it to be fed to float glass units.

[0170] To this end, the refining and homogenizing zone 200 has a first convective loop 210, referred to as the upstream recirculation loop, and a second convective loop 220, referred to as the downstream recirculation loop.

[0171] Preferably, the first convective loop 210, referred to as the upstream recirculation loop, is longitudinally shorter than the second convective loop 220, as shown in FIG.

[0172] Advantageously, the convection currents in the glass corresponding to the above loops 210, 220 agitate the glass, remove air bubbles, and increase the residence time of the glass in the refining homogenization zone 200, thus helping to obtain high quality glass.

[0173] The first convective loop 210 and the second convective loop 220 are separated by a reversal zone 230 of the loops 210, 220, which is determined by a hot spot (also called a "source point"), which corresponds to the hottest point of the glass in the refining homogenization zone 200 (typically a temperature above 1500°C).

[0174] The refining homogenization zone 200 has at least one burner 215, preferably here two aerial burners 215, which are placed under an arch 240 to obtain the hot spot that determines the reversal zone 230 of the loops 210, 220.

[0175] In the refining homogenization zone 200, part of the heat energy released by the combustion is transferred directly to the glass by radiation and convection, and another part is transferred by the arch 240, which transfers it back to the glass by radiation, and is for this reason specifically called the "hot top".

[0176] Preferably, the burners 215 in the refining homogenization zone 200 are cross-fire burners, shown diagrammatically in FIG.

[0177] Thus, heating of the glass in the refining and homogenizing zone 200 is obtained by the flame of the burner 215, which develops by combustion above the surface S of the glass.

[0178] In the hybrid furnace 10 according to the invention, the melting process of the glass that takes place in the melting zone 100 after it has been used in production is obtained solely with electrical energy.

[0179] Advantageously, therefore, the heating of the glass at the surface, caused by the combustion of fossil energy or equivalent fuels in said zone 200, is intended only to carry out a step of refining and homogenizing the glass removed from said melting zone 100.

[0180] In particular, in comparison with the hybrid furnace according to the third design described above, the equivalent fossil energy or fuel used by the burner 215 for combustion is not involved in the melting process, so that this fuel energy is used in the present invention as a "booster" for the electrical energy further used for melting.

[0181] Thus, the hybrid furnace 10 according to the present invention allows for a significant reduction in the ratio of fuel energy to electrical energy in the glass production process, with electrical energy being the primary energy and fuel energy being the secondary or auxiliary energy.

[0182] Advantageously, electricity accounts for more than 60%, or even more than 80%, of the total energy used in the glass making process in a hybrid furnace.

[0183] It can therefore be seen that the design of the hybrid furnace 10 according to the invention is particularly advantageous for reducing the carbon footprint when, on the one hand, the combustible energy is fossil energy, such as gas, and, on the other hand, the electrical energy is "green" electricity obtained in whole or in part from renewable, decarbonized energy.

[0184] The refining and homogenizing zone 200 may have more than two burners 215, in particular burners upstream and / or downstream of said reversal zone 230, which are placed above the surface S of the glass and can heat said surface S of the glass, thereby perfecting the refining and homogenization of the glass by removing bubbles (or gaseous defects) present in the molten glass.

[0185] In fact, by adjusting the power of the burners 215 it is possible to adjust the longitudinal distribution of the temperature and therefore the location of the hot spots, which is an important parameter for the operation of the furnace.

[0186] The burner 215 produces a combustion flame, which may be obtained in a known manner by combining different types of fuels and oxidizers, the choice of which is dependent on the carbon footprint of the glass production, or the direct and indirect emissions of greenhouse gases associated with the manufacture of the article, in particular carbon dioxide emissions (CO 2 ) also has a direct impact.

[0187] For combustion by burners 215 in the refining homogenization zone 200, oxygen present in air is typically used as the oxidizer, which may be enriched with oxygen to obtain excess oxygen air, or even substantially pure oxygen is used in the specific case of oxy-combustion.

[0188] Typically, the fuel used is natural gas. However, to further improve the carbon balance, it is advantageous to use biofuels, and in particular "biogas", i.e. gas essentially composed of methane and carbon dioxide, produced by methanation, i.e. fermentation of organic material in the absence of oxygen, or preferentially "biomethane" (CH 4 ) is also used.

[0189] More preferably, hydrogen fuel (H 2 ) is used, which is advantageously carbon-free compared to biogas.

[0190] Advantageously, the hybrid glass production furnace 10 according to the invention may comprise regenerators made of refractory materials operating (for example in pairs and inversely), or air / fume metal exchangers (also called recuperators), which respectively use the heat contained in the combustion gases resulting from the production to preheat the gases and thus improve combustion.

[0191] As mentioned above, the hybrid furnace 10 according to the present invention includes a separator 170 that is configured to prevent molten glass from returning from the refining and homogenizing zone 200 back to the melting zone 100 .

[0192] A separator 170 is placed in the first tank neck 160 between the refining and homogenizing zone 200 and the melting zone 100 to ensure a “no-return” function of the glass from the first convection loop 210 of glass.

[0193] In this first embodiment, the separation device 170 comprises a dam 172, which is intended to be partially immersed in the bath 130 of molten glass, as shown by FIGS.

[0194] More specifically, the separation device 170 according to the first embodiment is constituted only by a dam 172, which advantageously can prevent the molten glass from returning from the refining and homogenizing zone 200 to the melting zone 100.

[0195] Preferably, the dam 172 is located at the upstream end of the first tank neck 160 .

[0196] Advantageously, the dam 172 forming said separating device 170 allows a long residence time of the glass in the electric melting zone 100, which contributes to obtaining a high quality glass.

[0197] Preferably, the dam 172 extends laterally across the entire width of the first tank neck 160 as shown by FIG.

[0198] Advantageously, the dam 172 is mounted for vertical movement to enable adjustment of its immersion depth in the glass bath 130, whereby the portion 180 of the path of the molten glass located below can be varied as a function of adjusting the depth of the dam 172.

[0199] And, alternatively, the dam 172 is fixed so that the portion 180 of the molten glass path is constant, ie, determined by the immersion depth of the dam 172 into the glass bath 130 .

[0200] Advantageously, a dam 172 located upstream of the first tank neck 160 ensures immobilization of the layer 112 of vitrifiable mixture covering the glass bath 130 in the cold top electric melting zone 100 relative to the hot top refining homogenization zone 200.

[0201] Preferably, the compartmentation of the vitrifiable mixture layer 112 is secured by a dam 172, which extends vertically above the surface of the glass bath 130 to its extremity, as shown by FIG.

[0202] Preferably, the dam 172 is removable, i.e., dismantlable, so that the dam 172 can be replaced or repaired, particularly due to wear caused by contact with glass, thus facilitating maintenance of the hybrid furnace 10.

[0203] The dam 172 is made, for example, of a non-refractory metal or alloy, and said dam 172 can be cooled by a cooling fluid cooling circuit (not shown), in particular a circuit of the water jacket type.

[0204] Advantageously, the dam 172 helps cool the glass in the first tank neck 160 by restricting the flow within the first tank neck 160 thanks to a water-jacketed cooling fluid cooling circuit, which removes some of the heat (calories) transferred by the glass to the dam 172.

[0205] Alternatively, the dam 172 is made of a refractory material, typically a ceramic, such as fused refractory "AZS" (an acronym for Alumina-Zircon-Silica), or a refractory metal, such as molybdenum.

[0206] The hybrid furnace 10 further comprises at least one separation means 174 for separating the atmosphere from the cold top electric melting zone 100 and the atmosphere of the hot top refining and homogenizing zone 200, which contains in particular the fumes.

[0207] Advantageously, such a separation means 174 allows for isolating the atmosphere from the first tank neck 160 from that of the melting zone 100, especially when an air cooling device is implemented as a means for cooling the glass in the first tank neck 160.

[0208] Preferably, the separating means 174 are formed by a partition (or curtain) constituting an element attached to the superstructure of the hybrid reactor 10 .

[0209] The collection of blocks in contact with the glass is conventionally referred to as the "substructure," and the "superstructure" is all the material placed above the substructure.

[0210] The superstructure material is generally of different properties than the substructure tank block since it sits above the substructure tank block and is in contact with the atmosphere inside the furnace rather than with the glass.

[0211] Even if the materials used in the upper structure are the same as those in the lower structure, for example a hot top, these two parts of the furnace structure are generally distinct from one another.

[0212] Alternatively, the separating means 174 may consist of part of the superstructure, such as a double U-shaped partition opening to the outside.

[0213] And, advantageously, a dam 172 is mounted between or in the hollow bottom portion connecting the two wings of the "U" of the partition.

[0214] Preferably, the dam 172 and the atmosphere divider 174 are structurally distinct and separate elements in this first embodiment.

[0215] Preferably, the divider 174 does not contact the surface of the glass, but rather contacts the dam 172, thereby establishing the separation.

[0216] Advantageously, the partition 174 is located, for example, rearward, ie downstream of the dam, as shown in FIG.

[0217] Alternatively, the divider 174 may be located forward, ie, upstream, of the dam 172 or in the same vertical plane.

[0218] Alternatively, the dam 172 and the partition 174 are made of a single piece, thus ensuring a dual function: on the one hand, the first function of separating the glass between the melting zone 100 and the refining and homogenizing zone 200, and on the other hand, the function of separating the atmosphere of the melting zone 100 at the cold top 140 and the atmosphere of the refining and homogenizing zone 200 at the hot top 240.

[0219] And alternatively (not shown), if the dam 172 is not located upstream of the first tank neck 160 as shown by FIG. 1 , the hybrid furnace 10 advantageously has a blocking means, also called a “scoop”, which can keep the vitrifiable mixture layer 112 within the electric melting zone 100.

[0220] Preferably, a blocking means, such as a dam 172, is disposed at the upstream end of the first tank neck 160 to prevent the vitrifiable mixture present on the surface of the glass bath 130 from penetrating into the first tank neck 160.

[0221] In the first embodiment, besides the glass backflow prevention function, the dam 172 advantageously keeps the vitrifiable mixture layer 112 within the electric melting zone 100, thereby ensuring the function of such a blocking means.

[0222] Exemplary embodiments of such blocking means are described in more detail below under the reference numeral 176 in a second embodiment illustrated by FIGS. 3 and 4 and in a third embodiment illustrated in FIG.

[0223] In the first embodiment illustrated by FIGS. 1 and 2, the hybrid reactor 10 advantageously comprises a barrier 260 or weir wall, located within said loop reversal zone 230 .

[0224] Preferably, the barrier 260 extends vertically from the floor 250 of the refining / homogenizing zone 200 .

[0225] As shown in FIG. 1, the barrier 260 has a plateau portion that is immersed below the surface S of the glass and determines the path of the glass from a first convective loop 210, called the upstream recirculation loop, to a second convective loop 220, called the downstream recirculation loop.

[0226] Preferably, the hybrid furnace 10 comprises regulating means (not shown), such as an electric boost and / or bubblers, which are arranged in the refining and homogenizing zone 200 and can make it possible to regulate the convection of the loops 210, 220, thereby facilitating the glass production process.

[0227] Advantageously, the regulating means therefore comprise an electric boost, i.e. additional electric heating means with electrodes, and / or a bubbler, i.e. a system for injecting at least one gas, such as air or nitrogen, at the bed, which bubbles then cause the glass to move upwards.

[0228] Preferably, the hybrid furnace 10 includes at least one change 270 in depth of the floor 250 located within the refining homogenization zone 200 relative to the surface S of the glass.

[0229] The depth change 270 is located within the portion having the first convective loop 210 and / or within the portion having the second convective loop 220.

[0230] Advantageously, the glass depth change 270 is constituted, for example, by at least one plateau of the floor 250, here also by several plateaus, as illustrated by Fig. 1. Alternatively, the depth change 270 is constituted by at least one difference in the level of the floor 250.

[0231] The plateau of the floor 250 forming the depth change 270, ie here a reduction in depth, is constituted for example by at least one step 272 or even two steps.

[0232] The change in depth 270 can be more or less gradual, for example via a straight portion 274 in the case of the two steps 272 located upstream of the barrier 260, or alternatively via a sloped portion 276, as shown at the junction of the refining homogenization zone 200 and the glass cooling zone 300, for example in the case of the step 322 located downstream of the barrier 260.

[0233] Preferably, the cooling zone 300 therefore also includes a depth change 370 formed by a plateau.

[0234] As shown in FIG. 1 , the depth change 370 in the cooling zone 300 includes, for example, a step 322 located in the second tank neck 320 where the sloped junction 276 leads from the floor 250, and another step 332 located in the working end 330 downstream of the step 322.

[0235] The step 322 is also gently connected to the other step 332 by a sloped portion 376 located at the junction between the second tank neck 320 and the working end 330 .

[0236] Alternatively, the straight and inclined portions described with reference to FIG. 1 may be reversed between one step 272 and the other step 322, 332, respectively, or may only be of one type, i.e., either straight or inclined.

[0237] As shown in FIG. 1 and described with respect to the successive steps 322, 332, the cooling zone 300 has a floor 350 that is configured such that its depth to the glass surface S gradually decreases from the barrier 260 in a direction from upstream to downstream.

[0238] According to a third aspect of the invention, the hybrid furnace 10 comprises, downstream of the refining and homogenizing zone 200, a zone 300 for cooling the glass passed by a second convection loop 220, called the downstream recirculation loop.

[0239] The cooling zone 300 is formed by an equalization tank 310 and communicates with at least one flow passage 400, which is intended to supply high quality glass to a float glass unit on a molten metal bath (not shown), which is located downstream and forms the forming zone.

[0240] Advantageously, the equalization tank 310 of the cooling zone 300 has, from upstream to downstream, a second tank neck 320 and then a working end 330 .

[0241] Advantageously, the atmosphere of the refining and homogenizing zone 200 and the relatively cool atmosphere of the cooling zone 300 are separated from each other by a heat screen 360 that extends vertically from the top 340 to near the surface S of the glass, preferably without tempering in the glass.

[0242] Advantageously, in any vertical plane perpendicular to the furnace's central longitudinal axis A-A', there exists a point in the glass within the equalization tank 310 that has a longitudinal velocity component that extends from downstream to upstream.

[0243] After the equalization tank 310, no return flow occurs in the channel 400 that is intended to supply glass to the forming zone. In other words, the flow of glass in the channel 400 is a "piston" flow.

[0244] Advantageously, the hybrid furnace 10 according to the present invention is capable of delivering high quality glass having less than 0.1 bubbles per liter, preferably less than 0.05 bubbles per liter, which is most particularly suitable for feeding float glass units on a molten metal bath.

[0245] Advantageously, the hybrid furnace 10 can deliver high quality glass having less than 0.1 bubbles per liter to a float glass unit on a molten metal bath at a take-off rate of 400 tons per day or more, preferably 600-900 tons per day, or even 1000 tons per day or more.

[0246] Advantageously, the hybrid furnace 10 according to the present invention can provide an unloading rate similar to that of a flame furnace, with or without an electric booster, allowing the float unit to be supplied with high quality glass.

[0247] The hybrid furnace 10 for producing glass according to the invention feeds, via a flow passage 400, a float glass unit on a bath of molten metal, for example tin, intended for producing flat glass.

[0248] Advantageously, in a hybrid furnace 10 of the type described with reference to Figures 1 and 2, the glass manufacturing process comprises, in succession, the following steps: (a)-melting a vitrifiable mixture in a cold-top electric melting zone to obtain a molten glass; (b) - collecting the molten glass flowing from the melting zone to the refining and homogenizing zone through a first tank neck provided with a separator; (c) - refining and homogenizing the molten glass in a refining and homogenizing zone having a hot top, the refining and homogenizing zone having a first convection loop (referred to as an upstream recirculation loop) and a second convection loop (referred to as a downstream recirculation loop); (d)--Cooling the glass in a cooling zone formed by an equalization tank and traversed by a second convection loop.

[0249] Advantageously, the temperature of the molten glass collected in the melting zone 100 is reduced as it passes through the first tank neck 160 having a separator 170 formed by a dam 172 and / or a plateau 161 in the floor 165 .

[0250] Advantageously, according to an embodiment, the method includes an adjusting step (e) consisting of adjusting the depth of a movable dam 172, which is immersed in the glass and is placed in the first tank neck 160 connecting the electric melting zone 100 to the refining homogenization zone 200, to control the flow rate of the molten glass collected in the melting zone 100.

[0251] Advantageously, the adjusting step (e) makes it possible to vary the amount of molten glass passing from the electric melting zone 100 to the refining and homogenizing zone 200, for example as a function of the withdrawal rate.

[0252] After the cooling step (d) in the equalization tank 310, the glass flows into a channel 400 intended to supply high quality glass to a float glass unit.

[0253] Advantageously, the method includes a step of regulating the cooling of the glass in the first tank neck 160, in particular by selectively controlling a means 500 for cooling the glass, such as at least one air cooling device 510.

[0254] Advantageously, the amount of cooling air introduced into the first tank neck 160 by the intake means 512 of the air cooling device 510 is controlled, inter alia, as a function of the temperature of the glass.

[0255] In the following, a second embodiment of the hybrid reactor 10 shown in Figs. 3 and 4 will be described by comparing it with the first embodiment.

[0256] Indeed, the hybrid reactor 10 according to this second embodiment is similar to that described above with reference to Figures 1 and 2, so the description given therein also applies to this second embodiment, except as detailed below.

[0257] One difference with respect to the first embodiment is that the first tank neck 160 has a floor, indicated at 165, which is not flat and does not extend in continuation of the flat floor 150 of the electric melting zone 100.

[0258] Indeed, as shown by FIG. 3, the floor 165 of the first tank neck 160 is configured to form at least one plateau 161 .

[0259] Advantageously, the plateau 161 extends longitudinally over more than half the length of the first tank neck 160, or even over more than three-quarters of said length.

[0260] In this second embodiment, the first tank neck 160 of the hybrid furnace 10 advantageously has a length greater than that of the first embodiment, as can also be seen by comparing FIGS.

[0261] Advantageously, the length of the first tank neck 160 is configured to cool the glass intended to flow into the refining and homogenizing zone 200; since the molten glass obtained by electric melting generally has a relatively high temperature, especially compared to flame melting.

[0262] As an example, the temperature of the glass in the melting zone is about 1450°C, whereas the desired temperature of the glass in the downstream portion of the first tank neck is relatively about 1300°C to 1350°C.

[0263] According to a feature of the second embodiment, the at least one ledge 161 of the floor 165 of the first tank neck 160 forms part of the separation device 170 ensuring the function of preventing the glass from returning to the melting zone 100.

[0264] Advantageously, each separation device 170 according to this second embodiment has a dam 172, which, like that of the first embodiment, is associated with the at least one plateau 161 of the floor 165 of the first tank neck 160.

[0265] However, the dam 172 is not located upstream of the first tank neck 160, but rather is located longitudinally inside the first tank neck 160 having the at least one plateau 161 of the floor 165 between its upstream and downstream ends.

[0266] Preferably, the separator 170 herein has a single platform 161 on a floor 165 .

[0267] In comparison with a barrier (or weir wall), said pedestal 161 is directly formed by and not attached to the floor 165, whereby said pedestal 161 consists of the refractory material of the underlying structure forming said floor 165 of the first tank neck 160. Furthermore, the barrier is a narrow structure with a small thickness, which is subject to significant wear and does not ensure persistently that glass does not return to the melting zone.

[0268] As noted above, the plateau 161 is wide in that it extends longitudinally over a major portion of the length of the first tank neck 160, and the plateau 161 advantageously participates in cooling the glass within the first tank neck 160.

[0269] An exemplary embodiment of the pedestal 161 of the floor portion 165 as shown in FIG. 3 will now be described more particularly.

[0270] In FIG. 3, the plateau 161 has at least a first ascending portion 164, a second top portion 166, and a third descending portion 168, successively from upstream to downstream.

[0271] Advantageously, the plateau 161 extends laterally across the entire width of the first tank neck 160 .

[0272] Of course, such a plateau 161 may have numerous geometric variations with regard to its general shape and dimensions, in particular depending on the respective configurations of the different portions 164, 166 and 168 which compose it.

[0273] Preferably, the rising portion 164 is inclined at an angle (α) determined to form a ramp that causes the molten glass to rise toward the top portion 166 of the pedestal 161, as shown by FIG.

[0274] Preferably, the upwardly extending portion 164 is an inclined surface having an acute angle (α) of, for example, 20° to 70°, said angle (α) being indicated as the angle between the upwardly extending portion 164 of the plateau 161 and the horizontal (see FIG. 6 for better legibility), here taken as the reference point to the flat floor 150 of the melt zone 100.

[0275] In a variant (not shown), the ascending portion 164 may be stepped, e.g., stair-like, having at least one step, or two or more steps, which may or may not be identical in height and / or length dimensions.

[0276] Preferably, the top portion 166 is planar, forming a horizontal plateau. Advantageously, the top portion 166 extends longitudinally over a given length, here preferably over half the total length of the first tank neck 160.

[0277] The top portion 166 determines the maximum height H 1 that the pedestal 161 has, which in turn determines, in part only by the dam 172 , the portion 180 of the passageway of the molten glass within the first tank neck 160 .

[0278] Preferably, the descending portion 168 of the plateau 161 extends vertically and is connected to the downstream end of the horizontally extending flat top portion 166 by a right angle.

[0279] According to another embodiment, described below, for example, as shown in FIG. 6, the descending portion 168 is configured to gently entrain the flow of molten glass from the first tank neck 160 into the refining and homogenizing zone 200 .

[0280] Such a portion 168 is formed, for example, by an inclined plane, which may or may not have a step, in particular a step as described above for the alternative embodiment of the rising portion 164.

[0281] In addition to the at least one platform 161 just described, in this second embodiment, the separation device 170 also has at least one dam 172 as in the first embodiment, the dam 172 being partially immersed in the molten glass.

[0282] The dam 172 and pedestal 161 which combine to form the separator 170 may prevent molten glass from returning from the refining homogenization zone 200 back to the electric melting zone 100 , i.e., glass from returning from the first convection loop 210 .

[0283] Advantageously, the dam 172 in combination with said at least one plateau 161 jointly makes it possible to increase the residence time of the glass in the electric melting zone 100, which helps to obtain high quality glass.

[0284] Advantageously, the dam 172 can have the same features as described above for the first embodiment.

[0285] Preferably, the dam 172 is removable, i.e., dismantled, so that the dam 172 can be replaced or repaired, particularly due to wear caused by contact with glass, thus facilitating maintenance of the hybrid furnace 10.

[0286] Similarly, the dam 172 may be made, for example, of a non-refractory metal or alloy, and said dam 172 may be cooled by a cooling fluid cooling circuit (not shown), in particular a water-jacketed circuit.

[0287] Alternatively, the dam 172 is made of a refractory material, typically a ceramic, such as fused refractory "AZS" (an acronym for Alumina-Zircon-Silica), or a refractory metal, such as molybdenum.

[0288] As shown in FIG. 3, the at least one dam 172 is disposed longitudinally between the downstream and upstream ends of the first tank neck 160 .

[0289] Preferably, the dam 172 is positioned vertically above the top portion 166 of the plateau 161 .

[0290] Preferably, the dam 172 extends laterally across the entire width of the first tank neck 160, as shown by FIG.

[0291] Advantageously, the dam 172 is mounted for vertical movement to allow adjustment of the immersion depth within the glass bath 130, whereby the portion 180 of the molten glass passageway located above the top portion 166 of the height 161 is variable as a function of adjustment of the depth of the dam 172 relative to the glass depth P1, which is determined by the height H1.

[0292] Advantageously, the hybrid furnace 10 further comprises at least one separation means 174, such as a partition, for example, for separating the atmosphere from the electric melting zone 100 and the atmosphere of the refining and homogenizing zone 200, which contains in particular the combustion gases.

[0293] As shown in FIGS. 3 and 4, the separating means 174 is disposed at the upstream end of the first tank neck 160 adjacent the electromelting zone 100 .

[0294] In this second embodiment, the separating means 174, here formed by a partition, is in contact with the surface of the glass or is immersed with its free end, thereby not only establishing the above-mentioned atmospheric separation but also keeping the vitrifiable mixture layer 112 within the electric melting zone 100.

[0295] Advantageously, the separating means 174 thus provide another function, namely that of the blocking means 176, by which the layer 112 of vitrifiable mixture present on the surface of the glass bath 130 is prevented from penetrating into the first tank neck 160.

[0296] Therefore, in this second embodiment, the blocking means 176 are formed by the free end of a separating means 174 consisting of a partition which extends for this purpose at the bath surface 130 or which is preferentially also immersed in the glass bath 130.

[0297] Alternatively, the means 176 for blocking the layer 112 is structurally different from the separating means 174, and said blocking means 176 can be adjacent to said separating means 174 or can be separate therefrom.

[0298] Such a variant is also illustrated by FIG. 5 or FIG. 6, which represent a third embodiment, which will be explained in more detail later.

[0299] The separating means 174 is for example located downstream, i.e. remote from, the blocking means 176. Alternatively, the separating means 174 is attached to said blocking means 176.

[0300] Thus, in comparison with the first embodiment, the partition of the vitrifiable mixture layer 112 is now not secured by a dam 172, but either by the free end of a separating means 174 in this second embodiment shown by Figures 3 and 4, or by a separate blocking means 176 in the third embodiment shown by Figures 5 or 6.

[0301] The third embodiment illustrated by FIG. 5 (and FIG. 6 showing an alternative embodiment of the platform) will now be described, most particularly in comparison with the second embodiment.

[0302] In this third embodiment, the so-called "non-return" separation device 170, in comparison with the second embodiment shown in Figures 3 and 4, or even with respect to the first embodiment, is constituted only by at least one pedestal 161 in the floor 165 of the first tank neck 160, and therefore there is no movable dam 172.

[0303] Preferably, the hybrid furnace 10 has a pedestal 161 of the floor 165 having a height H2, as shown in FIG. 5, relative to the horizontal of the flat floor 150 of the melting zone 100 taken as a reference, said height H2 being relatively greater than the height H1, as shown in FIG. 3.

[0304] Advantageously, the plateau 161 of the floor 165 of the first tank neck 160 has the same shape as that described above with reference to FIG. 3, that is to say it is made up successively of an ascending portion 164 , a top portion 166 and a descending portion 168 .

[0305] As shown in FIG. 5, a depth P2 between the surface S of the molten glass and the top portion 166 of the pedestal 161 of the floor 165 is less than the depth P1.

[0306] Thus, in this third embodiment, the passage portion 180 of the molten glass is not determined by the dam 172, which is advantageously movably mounted, but only by the plateau 161 of the floor 165, so that the passage portion 180 cannot be specifically adjusted.

[0307] Even if the dam 172 is not present, the hybrid furnace 10, like the first and second embodiments, has at least one separation means 174, which is capable of separating the atmospheres from the electric melting zone 100 and from the refining and homogenization zone 200, respectively.

[0308] Moreover, as described above as a variant with respect to the second embodiment, the blocking means 176 is preferably distinct and separate from the separating means 174 described above.

[0309] Alternatively, as in the second embodiment, the blocking means 176 are formed by separating means 174 , the free ends, ie here the lower ends, of which are preferably immersed in the glass bath 130 .

[0310] According to one alternative embodiment of the plateau 161 of the floor 165 of the first tank neck 160 shown in FIG. 6, the descending portion 168 is configured to gently accompany the flow of molten glass toward the refining and homogenization zone 200.

[0311] Such a portion 168 is formed, for example, by an inclined plane, which may or may not be stepped, in particular stepped.

[0312] Preferably, portion 168 is inclined at an angle (β) determined to form a ramp that allows the molten glass to descend gradually toward floor 250 of refining homogenization zone 200 .

[0313] For the descending portion 168, the angle (β) is an obtuse angle that may have a value of, for example, 90° to 145°, said angle (β) corresponding to the interior angle noted at the junction of the top portion 166 and the descending portion 168 in FIG.

[0314] In a variant (not shown), portion 168 is not flat but has steps, e.g., is stepped having at least one step, or even two or more steps, which may or may not have the same height and / or length dimensions.

[0315] As shown by the figure, the depth of the glass is not the same here, at least on either side of the plateau 161 in the longitudinal direction, between the flat floor 150 of the electric melting zone 100 and the start of the floor 250 of the refining and homogenizing zone 200 downstream of the first tank neck 160, and this refining and homogenizing zone 200 is likely to have at least one variation in depth.

[0316] As indicated above, such a plateau 161 may have numerous geometrical variations with regard to its general shape, its dimensions and in particular according to the respective configurations of the different portions 164, 166 and 168 which compose it.

Claims

1. 1. A hybrid glass-making furnace (10) for producing glass to feed a unit for floating said glass on a molten metal bath, comprising: The hybrid furnace (10) comprises, from upstream to downstream: an electric melting zone (100) with a cold top (140) and with electrodes (110) for melting the vitrifiable mixture to obtain a glass bath (130); a refining and homogenizing zone (200) with a hot top, the refining and homogenizing zone (200) having a first convection loop (210) and a second convection loop (220); and a zone (300) for cooling said glass, formed by an equalization tank (310), passed by said second convection loop (220) and connected to at least one flow path (400); and the hybrid furnace (10) has at least one tank neck (160), called a first tank neck, having a floor (165) and connecting the electric melting zone (100) to the refining and homogenizing zone (200) of the glass, and the hybrid furnace (10) has a "no-return" separator (170) located in the first tank neck (160) and designed to prevent molten glass in the refining and homogenizing zone (200) from returning to the melting zone (100); A furnace characterized by:

2. 2. The furnace of claim 1, wherein the separation device (170) comprises at least one pedestal (161) of the floor (165) of the first tank neck (160).

3. 3. The furnace of claim 2, wherein the at least one plateau (161) of the floor (165) has, from upstream to downstream, at least one ascending portion (164), a top portion (166), and a descending portion (168).

4. Furnace according to any one of claims 1 to 3, wherein the separating device (170) comprises a dam (172) intended to be partially immersed in the glass bath (130).

5. A furnace as described in claim 3, wherein the separation device (170) has a dam (172) intended to be partially immersed in the glass bath (130), the dam (172) being positioned within the first tank neck (160) above the uppermost part (166) of the platform (161) of the floor (165).

6. 6. The furnace of claim 3 or 5, wherein at least one of the ascending portion (164) and the descending portion (168) of the at least one plateau (161) of the floor (165) is inclined with respect to the horizontal and / or has a top portion (166).

7. 6. The furnace of claim 2, 3 or 5, wherein the at least one pedestal (161) has a maximum height (H1, H2) that determines, in whole or in part, a passage portion (180) of the molten glass within the first tank neck (160).

8. 5. The furnace of claim 4, wherein the dam (172) is mounted so as to be vertically movable, thereby allowing adjustment of the depth of immersion into the glass bath (130).

9. 5. The furnace of claim 4, wherein the dam (172) is removable, i.e. dismantlable, thereby making it possible to replace the dam (172), in particular when worn, and facilitating maintenance of the furnace.

10. 6. The hybrid furnace (10) according to claim 1, 2, 3 or 5, further comprising at least one atmosphere separating means (174), such as a vertical partition, capable of separating an atmosphere from the electric melting zone (100) having a cold top and an atmosphere from the refining and homogenizing zone (200) having a hot top.

11. 6. The hybrid furnace of claim 1, further comprising a blocking means arranged at an upstream end of the first tank neck, the blocking means being capable of retaining a layer of vitrifiable mixture within the electric melting zone, thereby preventing the vitrifiable mixture present on the surface of the glass bath from penetrating into the first tank neck.

12. A furnace as described in claim 11, wherein the separation device (170) has a dam (172) intended to be partially immersed in the glass bath (130), and the means (176) for blocking the vitrifiable mixture layer (112) is formed by the dam (172).

13. A furnace as described in claim 11, wherein the hybrid furnace (10) has at least one atmosphere separation means (174), such as a vertical partition, capable of separating the atmosphere from the electric melting zone (100) having a cold top and the atmosphere of the refining and homogenization zone (200) having a hot top, and the blocking means (176) is formed by the separation means (174), the free end of which extends on the surface of the bath (130) or is immersed in the glass bath (130).

14. A furnace as described in claim 11, wherein the hybrid furnace (10) has at least one atmosphere separation means (174), such as a vertical partition, capable of separating the atmosphere from the electric melting zone (100) having a cold top and the atmosphere of the refining and homogenization zone (200) having a hot top, and the blocking means (176) is separate from the separation means (174), and the blocking means (176) is attached to the separation means (174) or is separate from the separation means (174).

15. 6. The hybrid furnace (10) according to claim 1, 2, 3 or 5, wherein the hybrid furnace (10) comprises glass cooling means (500), in particular at least one air circulation cooling device (510), capable of cooling the glass in the first tank neck (160).

16. 6. A furnace according to claim 1, 2, 3 or 5, wherein the electrode (110) is arranged on a surface so as to be immersed in the vitrifiable mixture, the diving electrode (110) preferably extending vertically.

17. 6. The furnace of claim 1, wherein the electrode (110) is disposed through a floor (150) of the melting zone (100) so as to be immersed in the vitrifiable mixture, the raised electrode (110) preferably extending vertically.

18. 17. The furnace of claim 16, wherein the electric melting zone (100) includes a low-convection zone, called a buffer zone (134), located between the free end of the plunge electrode (110) and the floor (150) of the melting zone (100).

19. 19. The furnace of claim 18, wherein the melting zone (100) is configured to have a depth (P) determined to obtain the low-convection buffer zone (134), preferably the depth (P) being greater than 600 mm, or more preferably greater than 800 mm.

20. 6. The furnace of claim 1, 2, 3 or 5, wherein the first convection loop (210) and the second convection loop (220) are separated by a reversal zone (230) of the loops (210, 220) determined by a hot spot or source corresponding to the hottest point of the glass, and the refining and homogenizing zone (200) has at least one burner (215) positioned to obtain the hot spot that determines the loop reversal zone (230).

21. 21. The furnace of claim 20, wherein the hybrid furnace (10) comprises a barrier (260) disposed within the loop reversal zone (230).

22. 6. The hybrid furnace (10) according to claim 1, 2, 3 or 5, further comprising an adjusting means, such as an electric boost and / or a bubbler, arranged in the refining and homogenizing zone (200) and capable of adjusting the convection in the loops (210, 220), thereby facilitating the glass production process.

23. 6. The furnace of claim 1, 2, 3 or 5, wherein the equalization tank (310) of the cooling zone (300) has, from upstream to downstream, a second tank neck (320) and a working end (330).

24. 6. The furnace of claim 1, 2, 3 or 5, wherein the hybrid furnace (10) is configured to supply glass to the float glass unit at a take-off rate of 400 tonnes per day or more, preferably 600 to 900 tonnes per day, or even 1000 tonnes per day or more, and wherein the high quality glass has less than 0.1 bubbles per liter, preferably less than 0.05 bubbles per liter.

25. 10. A flat glass manufacturing assembly comprising a hybrid furnace (10) for manufacturing the glass of claim 1, 2, 3 or 5, and a float glass unit on a molten metal bath, arranged downstream and supplied with glass by the furnace (10) via the at least one flow path (400).

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