Hybrid glassmaking furnace with three convection flows feeding a float unit

Abstract

The present invention relates to a hybrid glass making furnace (10) for feeding a float unit for floating glass on a bath of molten metal, the hybrid furnace (10) comprising, from upstream to downstream: - a hot crown melting zone (100) comprising at least several burners (105) capable of melting a glass batch (104) to obtain a glass bath (106), said melting zone (100) having a first convection current (C1) and bounded by a "no-return" separator (170) configured to prevent molten glass from returning into said melting zone (100); a glass refining zone (200) comprising a first refining zone (210) with at least one burner (205) and an electrode (230), and a second refining zone (220), said first refining zone (210) being separated from the melting zone (100) by said separating device (170) and from the second refining zone (220) by a wall (240), respectively, and glass being recirculated in the first refining zone (210) on the second convection current (C2) and in the second refining zone (220) on the third convection current (C3); and - a glass cooling zone (300) having an equalization tank (310) through which the third convection current (C3) flows, has.

Description

[Technical field]

[0001] The present invention relates to a hybrid glass making furnace having three convection currents feeding a float unit.

[0002] The present invention more particularly relates to a hybrid furnace for producing glass, which further brings together a fuel-fired melting zone, equipped with burners and advantageously assisted ("boosted") by electrical heating means, and a refining zone including a first refining zone, the first refining zone being configured such that the temperature of the glass therein can be controlled independently of the melting zone located upstream and the second refining zone located downstream.

[0003] The present invention also relates to a method for producing glass in such a hybrid glass-making furnace.

[0004] The method and hybrid glass making furnace according to the invention are not only capable of delivering high quality glass having less than 0.1 bubbles per liter, but also capable of supplying such glass at a take-off rate of at least 400 tons per day to a float unit for floating the glass on a molten metal bath, whereby float glass is intended to be produced. [Background technology]

[0005] Various examples of furnace designs for producing glass are known from the prior art, in particular depending on the final shape of the article to be produced, i.e. glass.

[0006] Thus, different furnace designs are differentiated depending on whether the envisaged production relates to fibreglass, industrial hollow glass forming or even flat glass forming.

[0007] One of the industrial challenges in the design of glass furnaces is to be able to obtain glasses whose quality requirements depend on the article; in this respect, the production of flat glass is relatively one of the most demanding.

[0008] Produced in very large quantities, flat glass is used in numerous applications thanks to its versatile properties, and is particularly widespread in the field of electronics (flat screens) or also in the building and automotive industries, where it can be processed using various techniques (bending, tempering, etc.), thus resulting in the glass on which a whole range of glass articles is based.

[0009] Thus, correspondingly addressing the challenges both in terms of quality and quantity, the present invention is aimed at the manufacture of glass for the industrial formation of such flat glass, which is conventionally obtained by means of a float unit for floating the glass on a bath of molten metal, typically tin; this float method is the reason why such flat glass is called "float" glass.

[0010] With respect to the production of flat glass by float units, the glass is expected to be compatible with both quality and quantity.

[0011] On the one hand, it is expected that large quantities of glass can be continuously supplied to the float unit or "float", i.e. generally at a take-off rate of more than 400 tonnes per day, advantageously more than 600 tonnes per day, or even 1000 tonnes per day or more, which is comparatively much larger than the quantities required for the production of glass fibres or for the formation of industrial hollow glass tubes.

[0012] On the other hand, it is expected that the float unit or "float" can be supplied with high quality glass, i.e. glass that is as free as possible from unmelted material or air bubbles, i.e. glass that generally has less than 0.5 bubbles / liter.

[0013] In fact, the quality of glass is determined in particular, but not exclusively, based on the number of bubbles present in the glass, expressed as "bubbles / liter". Thus, glass is considered to have a relatively high quality if it has a particularly low or even extremely small number of bubbles per liter.

[0014] It is further recalled that the presence of bubbles (or gaseous defects) in glass is inherent to the method of manufacturing glass in the glass production process: in the glass production process, three successive steps or stages are generally distinguished: melting, refining and homogenization, and thermal conditioning of the glass.

[0015] In fact, the presence of bubbles in the glass results from the melting process, in which a glass batch, also called "composition", is melted, consisting of raw materials including, for example, a mixture of sand, limestone (calcium carbonate), sodium carbonate and dolomite for the production of soda-lime glass (the glass most commonly used for the production of flat glass), to which cullets, consisting of glass fragments, are advantageously added, thereby in particular facilitating the melting.

[0016] The glass batch turns into a liquid mass in which the least miscible particles, i.e. those most rich in silicon dioxide or silica (SiO2) and lesser amounts of sodium oxide (Na2O), also dissolve.

[0017] Sodium carbonate (Na2CO3) begins to react with the sand grains from 775°C, thereby releasing carbon dioxide (CO2) bubbles into the liquid, which becomes more viscous as the carbonates are converted to silicates. Similarly, the conversion of limestone grains to lime and the decomposition of dolomite also result in the release of carbon dioxide (CO2).

[0018] The melting process is complete when there are no solid particles in the molten glass liquid, which becomes highly viscous but is then filled with air and gas bubbles at this stage of the manufacturing process.

[0019] And the refining and homogenization process, generally called refining, makes it possible to eliminate said gas bubbles present in the molten glass.

[0020] In a known manner, a "refining agent" is advantageously used during this process, i.e. a substance in low concentration which, by decomposing at the melting point of the bath, provides a gas that causes the bubbles to grow relatively large, thereby facilitating their rise to the surface of the glass.

[0021] And the thermal conditioning step of the manufacturing process allows the temperature of the glass to be reduced quickly; 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.

[0022] Naturally, there is a correspondence between the glass manufacturing steps just described and the furnace constructions intended to carry out these steps.

[0023] Generally, such furnaces for the manufacture of glass therefore comprise, in succession, a melting zone in which conversion into a glass bath is effected by melting the glass batch, then a refining and homogenizing zone for removing the glass bubbles, and finally a thermal conditioning zone in which the glass is cooled, thereby bringing it to a forming temperature which is much lower than the temperatures which the glass experiences during its production.

[0024] What is particularly noteworthy about the glass-making process just described is that the melting step involves the emission of carbon dioxide (CO2), one of the main greenhouse gases responsible for climate change.

[0025] Apart from the industrial challenge of producing high quality glass and high productivity at the lowest possible costs of construction and operation of furnaces, one of the other main challenges that the glass industry has to face today is the ecological one, i.e. the need to find solutions to reduce the carbon footprint (or CO2 footprint) associated with the glass production process.

[0026] To achieve carbon neutrality, a global process approach that aims to act at multiple points, reducing both direct and indirect emissions during production, or upstream and downstream emissions in the value chain, such as those associated with the upstream transport of materials and the subsequent downstream transport of goods, is preferred.

[0027] These points therefore include improving the design and material composition of articles, the energy efficiency of industrial processes, using renewable and decarbonized energy, working with raw material suppliers and logistics companies to thereby reduce their emissions, and finally, exploring technologies to capture and sequester residual emissions.

[0028] In terms of direct emissions, besides those inherent in the glass production process mentioned above, the type of energy most especially used for the high temperature melting step (above 1500°C) accounts for the largest contribution to the carbon footprint in the glass production process; since it is generally fossil fuels, most often natural gas, or even petroleum products such as heavy oil.

[0029] Research into new furnace designs should therefore not only make it possible to address the industrial challenges related to glass quality and adequate quantities, but also to reduce the carbon footprint of the glass production process, both in terms of direct and indirect carbon dioxide (CO2) emissions, in particular by reducing the use of fossil energy.

[0030] Glass is produced in furnaces that have continually evolved from the first pot (or crucible) furnaces, through the Siemens furnaces, generally considered the forerunners of today's large continuous casting glass furnaces, to the cross-fired furnaces capable of producing up to 1,200 tonnes of float glass per day.

[0031] The choice of energy used for melting therefore leads to a primary distinction between two large furnace designs for glass production: fuel-fired and electric furnaces.

[0032] According to the first design, fuel-fired furnaces generally use fossil fuels, particularly natural gas, in the burners; in this way, thermal energy is transferred to the glass by heat exchange between the flame and the surface of the glass bath.

[0033] 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 or "floats" intended to produce flat glass.

[0034] According to a second design, the electric furnace is a furnace in which thermal energy is generated by the Joule effect within a mass of molten glass.

[0035] In fact, glasses are insulating materials at room temperature and become electrically conductive at high temperatures, so that it is conceivable to use the Joule effect within the glass melts themselves and thereby heat them.

[0036] However, electric furnaces are used, for example, for the production of certain glass types, such as fluoride opal glass or lead crystal, or generally for the manufacture of glass fibres for thermal insulation.

[0037] It is therefore generally accepted by those skilled in the art that such electric furnaces, both in terms of quantity and especially in terms of the quality of the glass (bearing in mind less than 0.5 bubbles per liter), cannot supply a float unit for floating glass on a molten metal bath intended for the production of flat glass.

[0038] This is why today, fuel-fired furnaces (such as cross-fired furnaces) remain the only furnaces capable of supplying such float glass units.

[0039] Furthermore, fuel-fired furnaces have a variety of advantages which justify their widespread use in glass production.

[0040] However, fuel-fired furnaces rely on the use of fossil energy, essentially natural gas, for fuel and therefore their carbon footprint is relatively incompatible with the objective of reducing carbon dioxide (CO2) emissions, i.e., reducing the carbon footprint of the glass production process.

[0041] In complementing the disclosure of prior art furnace designs for glass production, reference is also made to a "third design" or evolution of furnaces, which have been improved in recent years, thereby addressing ecological issues, in particular the reduction of carbon dioxide (CO2) emissions.

[0042] This third furnace design is based on a fuel-fired furnace, but it uses supplemental electrical heating, thereby specifically increasing furnace output instantaneously or even improving glass quality.

[0043] Therefore, such furnaces are also called "electrically assisted fuel-fired furnaces."

[0044] Thus, the furnace according to this third design combines several energy sources, fossil and electrical, and is therefore also called a "hybrid" furnace.

[0045] The addition of electrical auxiliary heating makes it possible to increase the melting capacity of a fuel-fired furnace, which is limited by the heat transfer that occurs between the flame and the surface of the glass bath.

[0046] However, the operation of such hybrid furnaces has always been primarily based on the use of fossil fuels, typically gas, and therefore the ultimate impact in improving the carbon footprint of the glass production process remains limited.

[0047] In fact, electricity is used only as an auxiliary and therefore its impact is proportionate, i.e. limited, generally not contributing more than 15% of the heat supply required for the melting process.

[0048] Furthermore, to improve the carbon footprint, the electricity used must also be what is called "green" electricity, i.e. electricity generated from renewable, decarbonized energy sources. Summary of the Invention [Problem to be solved by the invention]

[0049] The present invention has in particular the aim of proposing a novel design of a glass production furnace, and a production method, capable of providing high quality glass for feeding float glass units intended to produce flat glass, while having an energy consumption that makes it possible to obtain a significant reduction in the carbon dioxide (CO2) emissions associated with the glass production process. [Means for solving the problem]

[0050] To this end, the invention relates to a hybrid glass production furnace for supplying a float unit for float glass on a molten metal bath, said hybrid furnace comprising, from upstream to downstream: - a hot crown melting zone, comprising at least several burners capable of melting a glass batch to obtain a glass bath, said melting zone having a first convection current and bounded by a "no-return" separator configured to prevent the molten glass from returning into the melting zone; - a glass refining zone comprising a first refining zone having at least one burner and an electrode, and a second refining zone, the first refining zone being separated from the melting zone by the separation device and from the second refining zone by a wall, and glass recirculating in the first refining zone on a second convection current and in the second refining zone on a third convection current; and - a glass cooling zone having an equalization tank through which the third convection current flows; has.

[0051] Advantageously, the hybrid furnace is capable of supplying high quality glass to a float unit for float glass on a molten metal bath at an unloading rate of more than 400 tonnes per day, preferentially 600 to 900 tonnes per day, or even more than 1000 tonnes per day.

[0052] The furnace according to the present invention is said to be "hybrid" in analogy with the third furnace design described above; thus, the term "hybrid" is used to describe it since it uses two different energy sources: electrical energy and fuel energy, respectively.

[0053] However, the analogy with the present invention does not end there, since electrical energy is advantageously used not only as an auxiliary to the melting step, but also primarily during the refining step, which is carried out separately from the melting step, so that the contribution of electrical energy to the overall production process is substantial compared to the prior art.

[0054] In fact, the present invention advantageously proposes a much greater level of hybridization than known to date in the prior art, since the contribution of electrical energy in the provision of heat by all electrodes arranged in the first refining zone, or even as a supplement in the melting zone and the second refining zone, represents at least 40% of the total heat provided to the furnace, and even more.

[0055] Advantageously, therefore, the hybrid furnace according to the invention relies in part on electrical energy, taking advantage of the increasing availability of "green" electricity, e.g. obtained from wind energy, solar energy, etc., and not from fossil fuels, e.g. coal or oil.

[0056] Advantageously, the fuel energy used in the melting zone burners is not a fossil energy, such as natural gas, but another equivalent fuel energy, preferentially hydrogen, as an alternative to biomethane.

[0057] Thus, the hybrid furnace according to the invention combines a fuel-fired melting zone with electrical assistance and a preferentially electrical refining zone with auxiliary fuel combustion, and comprises a first refining zone and a second refining zone, each separated from the other.

[0058] Thanks to such a combination, 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, which can then be advantageously fed to float glass units or "floats" intended for the production of flat glass.

[0059] In fact, the hybrid furnace according to the invention proposes a novel design, based on a separation of zones obtained upstream by a separation device, such as a wall or barrier at the neck and / or a ridge at the bottom of the neck, and downstream, another wall, thereby resulting in a separation of the steps of the manufacturing method respectively carried out therein.

[0060] Thanks to this separation it is therefore possible to control each step of the process independently from the others and in so doing, most especially to optimise the energy consumption of each step, which is beneficial for the carbon footprint.

[0061] Advantageously, in particular, molten glass does not return from the refining zone to the melting zone in the hybrid furnace according to the invention, so that no convection or glass recirculation loop extends from the refining zone to the melting zone as in prior art furnaces in which a first stream in the melting zone and a second stream in the refining zone exchange glass with each other.

[0062] In the prior art, unlike the present invention, the heat supply does not operate separately for the melting or refining process, and there are no separate zones with independent flows.

[0063] Indeed, since part of the heat supplied, for example in the refining zone of a prior art hybrid furnace, is generally directed upstream by the first flow in the melting zone, it is not possible to precisely and independently control each of the various melting, refining and cooling steps, but only to control the entire production process.

[0064] In the furnace according to the invention, the step of refining the glass is advantageously carried out on glass that contains little or no unmelted material, in particular by means of "non-return" separating devices, such as a neck with at least a first wall, or even a bottom ridge, and / or a barrier, making it possible to increase the residence time of the glass in the melting zone.

[0065] In the present invention, high quality glass is obtained in particular thanks to a refining zone that is independent, separate and controllable from the melting zone, which makes it possible to dissociate the thermal regions from each of these zones.

[0066] In prior art furnaces, the lack of separate and independent convection makes such a separation of heat zones impossible, and therefore separate and finely optimized heat supply, especially for the melting and refining steps, is not possible.

[0067] In the present invention, the three convection currents contained in the melting zone, the first refining zone and the second refining zone, respectively, are controlled separately.

[0068] Advantageously, the use of mainly fuel energy for the melting process, preferentially assisted by electrical energy, allows for a relatively efficient melting of the glass batch, in particular at lower temperatures than electrical melting would require, and therefore the choice of melting by combustion is also beneficial in terms of furnace life.

[0069] Advantageously, the electrical energy used for the electrodes of the first refining zone is converted into a heat supply used only for refining and is not transmitted to the melting zone, in particular since it cannot be returned to said melting zone by the (non-return) separation device, and therefore the first and second convection flows of the glass are independent of each other.

[0070] Advantageously, the hybrid furnace according to the invention forms a double harmony, on the one hand based on the replacement of fossil energy as fuel and, on the other hand, based on the increased availability of "green" electricity, e.g. obtained from wind energy, solar energy, etc.

[0071] Advantageously, the fuel energy used in the burners of the melting and refining zone is not a fossil energy, such as natural gas, but another equivalent fuel energy, preferentially hydrogen, as a replacement for biomethane.

[0072] The hybrid furnace according to the invention can therefore address not only the problem of the quantity and high quality of glass required to feed the float unit or "float", but also the environmental problem, thereby making it possible to substantially reduce the carbon footprint of the production process.

[0073] In a preferred embodiment, the hybrid furnace has a neck, referred to as the first neck, that connects the melting zone to the refining zone.

[0074] Advantageously, the first neck of the hybrid furnace, in combination with a separation device, contributes to the temperature control of the glass by making it possible to ensure the cooling of the glass flowing from the melting zone to the glass refining zone, thanks to which the primary and secondary convection currents are controlled, ultimately with the benefit of producing a desired quantity of high quality glass.

[0075] Advantageously, the hybrid furnace comprises glass cooling means capable of selectively cooling the glass in the first neck.

[0076] Advantageously, the means for cooling the glass can ensure a variable, i.e. adjustable, cooling, which is determined in particular on the basis of the temperature of the glass. Preferably, the hybrid furnace comprises an air circulation cooling device forming all or part of said means for cooling the glass.

[0077] Advantageously, the means for cooling the glass can ensure a variable, i.e. adjustable, cooling, which is determined in particular on the basis of the temperature of the glass.

[0078] Advantageously, high quality glass is obtained in particular by a refining step carried out after the melting step, said refining step being additionally controlled by cooling of the glass in the first neck, this cooling contributing to obtain two convection currents in order to control the induction of the glass.

[0079] Advantageously, high quality glass is also obtained by a separator device, which is arranged in the first neck of the hybrid furnace and configured to prevent the molten glass from returning from the refining zone to the melting zone, such that the flow of glass in the first neck is a "piston" type flow.

[0080] The separator limits the amount of molten glass flowing downstream from the melting zone, thus facilitating cooling of the glass in the first neck, which is why there is a synergistic effect between the separator and the first neck.

[0081] Additionally, the separation device also prevents glass from returning from the refining and homogenizing zone to the melting zone and into the first neck, allowing the molten glass to be cooled in the first neck and refined in the refining and homogenizing zone having a first convection loop and a second convection loop.

[0082] Advantageously, the separation device is formed by a barrier and / or a ridge at the bottom of the first neck, which, each alone or together, can prevent the molten glass from returning from the refining zone to the melting zone of the hybrid furnace according to the invention.

[0083] In comparison with the hybrid furnace according to the invention, furnaces with submerged throats connecting the melting zone to the refining zone cannot ensure such a function of preventing glass return: in fact, a return flow of glass exists in such throats, in particular due to material wear.

[0084] In addition, the glass flowing in the throat does not come into contact with the atmosphere and therefore it is not cooled on the surface, as in the first neck, which in particular (but not limited to) advantageously has means for cooling the glass, such as an air circulation cooling device.

[0085] Furthermore, the throat has a cross section that is structurally limited and therefore, unlike the hybrid furnace according to the invention, which has a preferential first neck, it is not possible to obtain an extraction velocity to feed the float unit.

[0086] The hybrid furnace according to the invention consists of a combination of features and not a juxtaposition; because there are interactions between the technical features, in particular synergies between the melting zone with the first convection and the refining zone with the second and third convection.

[0087] In a preferred embodiment, the first neck and associated separation device can respectively allow the glass to cool and prevent the glass from returning to the melting zone.

[0088] Thanks to the first neck and the separating device, the temperature of the glass can be separately and precisely controlled in the melting zone on the one hand and in the refining zone on the other hand.

[0089] Preferably, the length of the first neck is configured to obtain cooling that reduces the temperature of the glass. Indeed, the molten glass obtained by electric assisted melting generally has a relatively high temperature, especially compared to fuel-fired melting alone.

[0090] 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 neck may be within about 1300°C to 1350°C.

[0091] Advantageously, the hybrid furnace comprises glass cooling means arranged in the first neck, by means of which the glass can be selectively cooled, i.e. controlled cooling, thereby actively adjusting the glass temperature.

[0092] Preferably, the cooling means are formed by at least one air circulation cooling device, air being introduced into the atmosphere of the first 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.

[0093] According to another exemplary embodiment, the cooling means are immersed in the glass flowing from upstream to downstream through the first neck, thereby enabling its cooling.

[0094] Such cooling means immersed in the glass are, for example, formed by a barrier, which forms all or part of the separation device and which is cooled by a cooling circuit containing a heat transfer fluid, in particular a circuit of the "water jacket" type.

[0095] According to another example, the cooling means are formed by a vertical stud, which is placed in the first neck and immersed in the glass and is cooled by a cooling circuit containing a heat transfer fluid, thereby removing the heat transmitted by the glass.

[0096] According to yet another exemplary embodiment, the cooling means are capable of cooling the first neck structure which is in contact with the glass, the cooling being performed from outside the first neck structure.

[0097] Of course, the cooling means associated with the first neck according to the various examples just given can be implemented alone or in combination.

[0098] Advantageously, the means for cooling the glass associated with the first neck allows selective control of the temperature of the glass, which is likely to vary, particularly when the withdrawal speed varies; this is because an increase in the withdrawal speed causes the temperature of the glass to increase.

[0099] In comparison with such means for cooling the glass associated with the first neck, such variable cooling of the glass would not be possible at the throat.

[0100] Other characteristics of the furnace according to the invention are: - the separation device can prevent glass from returning from the first refining zone to the melting zone, so that the first convection current in the melting zone can be controlled independently from the second convection current in the first refining zone; - the separation device is configured to limit the amount of glass passing from the melting zone to the first refining zone, thereby increasing the residence time of the glass in the melting zone; the separation device comprises a wall, referred to as the first wall, which is configured to prevent the molten glass from returning from the refining zone to the melting zone; - the hybrid furnace has a neck, called the first neck, which connects the melting zone to the refining zone; - the hybrid furnace has glass cooling means, in particular an air circulation cooler, capable of cooling the glass in the first neck; - the first neck has a bottom, and the separation device has at least one ridge at the bottom of the first neck, the ridge configured to prevent molten glass from returning from the refining zone to the melting zone; - the at least one ridge at the bottom has, from upstream to downstream, at least one ascending segment, a crest segment, and a descending segment; - at least one of the ascending and descending segments of the at least one bottom ridge is inclined with respect to the horizontal and / or has a top segment forming a plateau; - the ridge has a maximum height that determines, in whole or in part, the passage of the molten glass in the first neck; - the separation device has at least one barrier, which extends vertically and is partially immersed in the glass bath flowing from the melting zone to the glass refining zone through the first neck, said barrier being configured to prevent the molten glass from returning from the refining zone to the melting zone; - a barrier is disposed at an upstream end of said first neck; - the separating device has a barrier and said at least one ridge at the bottom of the first neck; - the barrier is disposed above the top segment of the bottom ridge of the first neck; - the barrier is mounted so as to be vertically movable, thereby allowing the depth of immersion into the glass bath to be adjusted, thereby varying the portion of molten glass passing through based on the adjustment of the depth of said barrier; - the barrier is removable, i.e. dismantlable, thereby allowing its replacement, in particular in case of wear, and facilitating the maintenance of the furnace; - the hybrid furnace has separation means, for example curtains, for separating the atmosphere of the melting zone from the atmosphere of the refining zone; - the hybrid furnace has a blocking means capable of retaining a layer of glass batch present on the surface of the glass bath in the melting zone, said blocking means being arranged at the downstream end of the melting zone; - the blocking means is formed by a separating means, the free ends of which extend at the surface of the bath or are immersed in the glass bath; - the blocking means is separate from said separating means, said blocking means being attached to the separating means or being separate from the separating means; - the hybrid furnace is configured to supply the float glass unit with high quality glass having less than 0.1 bubbles per liter, preferably less than 0.05 bubbles per liter, at a take-off rate of at least 400 tonnes / day, preferentially 600-900 tonnes / day or even 1000 tonnes / day or more; - the melting zone has electrodes, which are immersed in the glass bath and constitute auxiliary ("booster") electric heating means; - the electrode is positioned in the downstream part of the melting zone; - electrodes in the melt zone are selectively controlled to control a first convection current in the melt zone; - the electrodes in the melting zone are selectively controlled to regulate the temperature of glass passing from the melting zone to the first of the refining zones; - the electrodes and said at least one burner of the first refining zone are capable of heating the glass to a temperature of more than 1450°C; - the at least one burner is arranged in the refining zone to obtain a hot spot at the surface that determines a reversal zone between the second convection current and the third convection current; - electrodes in the first refining zone are selectively controlled to control a second convection current within the first refining zone; - the wall is configured to prevent glass from returning from the second refining zone to the first refining zone, so that the second convection current in the first refining zone can be controlled independently from the third convection current; - the wall is configured to restrict the amount of glass passing from the first refining zone to the second refining zone, thereby increasing the residence time of the glass in the first refining zone; - the second refining zone has electrodes immersed in the glass and that can be selectively controlled to control the third convection current; The equalization tank of the cooling zone has, from upstream to downstream, a neck, called the second neck, and a regulator.

[0101] The invention further proposes an assembly for producing flat glass, comprising a hybrid glass production furnace according to the invention and a float unit for floating glass on a molten metal bath, which is arranged downstream and is fed with glass by said hybrid furnace via at least one flow path.

[0102] The invention also proposes a method for producing glass in a hybrid furnace, such as that described above, comprising the following steps: (a)-Melting a glass batch in a hot crown melting zone containing a first convection current of glass; (b) - refining the glass in a first refining zone having a second convection current and then refining the glass in a second refining zone having a third convection current, the first refining zones being separated from the melting zone and from the second refining zone, respectively, and thereby capable of being controlled independently of each other; (c) - Cooling the glass in a cooling zone formed by an equalizing tank through which the third convection current flows.

[0103] Advantageously, the method comprises a step of controlling an auxiliary electrode arranged in the melting zone to control said first convection current of glass, separated by a "no-return" separation device, independently of the second convection current of the first refining zone.

[0104] Advantageously, the method includes a step of controlling an electrode arranged in the first refining zone to control said second convection flow of glass, separated by a wall, independently from a third convection flow in the second refining zone.

[0105] Advantageously, the method includes controlling electrodes disposed within a second refining zone to control said third convection flow of glass, the electrodes being selectively controlled to adjust the temperature of the glass in said second refining zone of the refining zone.

[0106] Advantageously, the method includes a step of regulating the cooling of the glass in the first neck, in particular by selectively controlling the means for cooling the glass, such as at least one air cooler.

[0107] Advantageously, the amount of cooling air introduced into the first neck by the suction means of the air cooling device is controlled in particular on the basis of the temperature of the glass.

[0108] 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]

[0109] [Figure 1] FIG. 1 shows a hybrid furnace for glass production according to a first embodiment of the invention, further comprising a hybrid melting zone associated with a two-part refining zone having two convection and cooling zones, in a side view illustrating a first refining zone, the first refining zone being bounded on the upstream side by a first wall forming a "no-return" separator with the melting zone and on the downstream side by a second wall ensuring separation from the second refining zone;

[0110] [Diagram 2] FIG. 2 shows a top view of the furnace according to FIG. 1 and also of the electrodes arranged in the melting zone, in the first refining zone and in the second refining zone, respectively, and of the cooling zone formed by an equalizing tank with a neck and a regulator.

[0111] [Diagram 3]FIG. 3 is a side view, similar to FIG. 1, showing a hybrid furnace according to a second embodiment of the invention, having a first neck connecting the melting zone to a refining zone divided into two parts, illustrating an upstream separation device formed by at least one ridge at the bottom of the first neck, and a downstream wall, which ensures the separation of the first refining zone from the melting zone and from the second refining zone, respectively.

[0112] [Figure 4] FIG. 4 is a top view, similar to FIG. 2, showing the furnace according to FIG. 3 in which the separation device for preventing the return of the glass to the melting zone is formed by a raised part at the bottom of the first neck, also illustrating electrodes arranged in the melting zone, in the first refining zone and in the second refining zone, respectively, and a cooling zone formed by an equalizing tank with a second neck and a regulator.

[0113] [Diagram 5] FIG. 5 is a side view showing in detail the first neck of the hybrid furnace according to FIG. 3 and illustrating an exemplary embodiment of at least one raised portion of the bottom of the first neck;

[0114] [Figure 6] FIG. 6 is a side view, similar to FIG. 5, showing in detail a third embodiment of a separation device in a hybrid furnace identical to that of FIGS. 3 to 5, also illustrating a movable barrier associated with a raised part at the bottom of the first neck forming said separation device, and a curtain forming an atmospheric separation means between the melting zone and the refining zone and ensuring, at the surface, the blocking of the glass batch in said melting zone.

[0115] [Figure 7]FIG. 7 is a side view showing in detail an alternative embodiment of a separation device for a hybrid furnace according to FIG. 5, having a first neck provided with a bottom ridge (without a barrier) and illustrating a means for blocking the glass batch separate from the curtain forming the separation means, unlike the one shown by FIG. 6; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0116] 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 1-7.

[0117] The terms "upstream" and "downstream" will also be used conventionally 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.

[0118] In this specification, the terms "upstream" and "downstream" correspond to the flow direction of the glass in the furnace, where the glass flows from upstream to downstream along the longitudinal central axis A-A' (upstream side is A and downstream side is A') of the hybrid furnace as shown in Figure 2 or Figure 4.

[0119] Furthermore, the terms "flow" and "loop" are synonymous herein, as these terms relate to the recirculation of glass within a furnace in a clockwise or counterclockwise direction, and are well known to those skilled in the art, as are the concepts of "hot crown" and "cold crown" in furnaces intended for glass production.

[0120] 1 and 2 show side and top views, respectively (not to scale), of a hybrid furnace 10 for making glass illustrating a first embodiment of the present invention.

[0121] In analogy with the third furnace design described above, the term "hybrid" is used herein to describe the furnace according to the present invention, since it uses two different energy sources: fuel energy and electrical energy, respectively.

[0122] According to one important feature, the hybrid furnace 10 according to the invention can be supplied with a float unit for floating glass on a bath of molten metal, typically tin, for the production of flat glass.

[0123] Indeed, feeding molten glass to a float unit (or "float") requires that the hybrid glass making furnace 10 be able to meet the dual requirements of glass quantity and glass quality, respectively.

[0124] Advantageously, the hybrid furnace 10 according to the invention is capable of delivering high quality glass at an output rate of more than 400 tonnes per day, preferentially between 600 and 900 tonnes per day, or even more than 1000 tonnes per day.

[0125] Advantageously, the hybrid furnace 10 is not only capable of delivering the amount of glass required to feed the float unit, but also capable of delivering high quality glass having less than 0.1 bubbles per liter, preferentially less than 0.05 bubbles per liter.

[0126] The hybrid furnace 10 comprises, successively from upstream to downstream on the furnace's central longitudinal axis A-A', at least one melting zone 100, a refining and homogenizing zone 200, hereinafter referred to as the refining zone, and a glass cooling zone 300.

[0127] The hybrid furnace 10 is of the “hot crown” type and is designated below with the reference numeral 12 in a melting zone 100 .

[0128] According to a first feature of the present invention, the melting zone 100 of the hybrid furnace 10 has a first convection current (C1) that forms a glass recirculation loop in a counterclockwise direction.

[0129] Preferably, the hybrid furnace 10 has at least one charging opening 102 through which a glass batch 104 is introduced into the upstream part of the melting zone 100, here in the longitudinal direction in the mid-axis A-A' of the furnace as indicated by the arrow in FIG. 1.

[0130] In a known manner, the glass batch 104 (also called "composition") comprises raw material and cullet. Cullet consists of glass fragments obtained by recycling glass, which are crushed and washed and then added to the raw material, thereby producing glass again.

[0131] Advantageously, the cullet facilitates melting, i.e., the conversion of the glass batch into glass by melting.

[0132] Furthermore, cullet allows the glass used to be reused by recycling it (because glass is infinitely recyclable), thus proportionally reducing the amount of raw material required for the production of glass and contributing to a reduction in the carbon footprint of the production process.

[0133] In a known manner, the glass batch 104 is introduced into the melting zone 100 of the hybrid furnace 10 by a charging device (not shown), also referred to as a batch charger.

[0134] A melting zone 100 having a hot crown 12 has at least several burners 105 capable of melting a glass batch 104 to obtain a glass bath 106 .

[0135] In the melting zone 100, the thermal energy released by the combustion performed by the burners 105 is transferred directly to the glass batch, or more generally to the glass bath 106 by radiation and convection; another part is carried by the crown 12, which returns it by radiation, hence the name "hot crown".

[0136] As shown in Figures 1 and 2, burners 105 are advantageously positioned in the upstream portion of the melting zone 100, and the number of burners 105 shown (e.g., here three) is purely illustrative and therefore completely non-limiting.

[0137] The burners 105 of the melting zone 100, referred to as aerial burners, are positioned between the hot crown 12 and the surface of the molten glass bath 106, which is partially covered, particularly on the upstream side, by the glass batch 104, shown with dots in FIG. 1.

[0138] Preferably, the burners 105 in the melting zone 100 are referred to as cross-firing burners, so named because they are arranged transversely, perpendicular to the glass flow in the hybrid furnace 10, from upstream to downstream along the median axis A-A'.

[0139] The flame generated by combustion by the cross-firing burners 105 extends in the short direction, whereby it is possible to adjust the longitudinal distribution of temperature by adjusting the output of each of the burners 105.

[0140] Preferably, the burners 105 are positioned transversely on either side of the melting zone 100 as shown by FIG.

[0141] The combustion performed by the burner 105 can be obtained in known manner by combining different types of fuels and oxidizers, the choice of which also has a direct impact on the carbon footprint of glass production, i.e. the direct and indirect greenhouse gas emissions associated with the production of the article, in particular the emission of carbon dioxide (CO2).

[0142] For combustion by the burners 105 in the melting zone 100, oxygen present in air is typically used as the oxidizer, and this air may be enriched with oxygen to obtain oxygen-enriched air, or substantially pure oxygen may be used in the specific case of oxy-fuel combustion.

[0143] Typically, the fuel used is natural gas. However, green fuels are also advantageously used, especially "biogas", i.e. gas essentially composed of methane and carbon dioxide produced by methanation, in other words fermentation of organic material in the absence of oxygen, or preferentially "biomethane" (CH4).

[0144] Compared to biogas, advantageously carbon-free hydrogen (H2) will moreover be used preferentially.

[0145] Advantageously, the hybrid glass production furnace 10 according to the invention may have regenerators made of refractory material, or even metallic air / exhaust gas exchangers (also called recuperators), operating (for example in pairs and in counter-rotation), which respectively use the heat contained in the exhaust gases resulting from the production to preheat the gases and thus improve combustion.

[0146] Advantageously, the burners 105 of the hybrid furnace 10 have a heating capacity of 0.3 m per tonne of glass. 2 The glass batch 104 can be melted over a surface area of ​​less than 100 mm.

[0147] Such surface area would be relatively large in an electric furnace according to the second design, and thus the fuel-fired hybrid furnace 10 has the advantage of being relatively compact.

[0148] Furthermore, the burners 105 also make it possible to carry out the process of melting the glass batch 104 at relatively low temperatures compared to electric melting, which contributes to a reduction in the phenomenon of wear on the furnace substructure and is in favor of extending the furnace's service life.

[0149] In a glass making furnace, all of the blocks that come into contact with the glass are conventionally referred to as the "substructure" and all of the material placed above the substructure is conventionally referred to as the "superstructure."

[0150] The upper structure material is located above the lower tank block, is in contact with the furnace atmosphere but not with the glass, and is generally of different nature than that of the lower tank block.

[0151] Even if the materials used in the upper structure are similar to those in the lower structure, such as in the case of a hot crown as in this embodiment, these two parts of the furnace structure are generally distinct.

[0152] The hybrid furnace 10 has a bottom 108. Preferably, the bottom 108 here is planar in the melting zone 100, such that the depth P of the glass bath 106 between the surface of the glass bath 106 and the bottom 108 is substantially constant.

[0153] Preferably, melting zone 100 comprises an electrode 110, which is immersed in glass bath 106 and which advantageously constitutes a supplementary ("booster") electrical heating means.

[0154] In fact, the electrodes 110 in the melting zone 100 are complementary heating means to the burners 105, which are the main heating means making it possible to melt the glass batch 104. As a result, the process of melting the glass is obtained using fuel energy and, as a supplement, electrical energy.

[0155] Preferably, the heat provided by the electrodes 110, as an auxiliary to the burners 105, represents 5-25% of the total heat of the melting process carried out in the melting zone 100, preferentially about 10-15%.

[0156] Preferably, the electrodes 110 are mounted through the bottom 108 of the melting zone 100 of the furnace via electrode holders (not shown), which in particular make it possible to supply them with electrical power.

[0157] Preferably, the electrodes 110 extend vertically as shown in Figure 1. Alternatively, the electrodes 110 extend diagonally, i.e., inclined at an angle to the vertical.

[0158] According to another alternative arrangement, the electrode 110 penetrates at least one side wall that defines the melt zone 100, the electrode 110 then extending horizontally and / or diagonally.

[0159] Advantageously, the electrode 110 is made of molybdenum, a refractory metal that can withstand temperatures of 1700° C. and is particularly suitable for heating the glass bath 106 in the melting zone 100 .

[0160] Furthermore, as with the burners 105, the number of electrodes 110 shown here in Figures 1 and 2, six, is purely illustrative and thus completely non-limiting.

[0161] Preferably, the melting electrodes 110 are evenly distributed in the transverse direction in the melting zone 100 .

[0162] Advantageously, the electrode 110 is positioned in a downstream portion of the melt zone 100 extending over more than half the length (L) of said melt zone 100, or even over more than two-thirds of said length (L).

[0163] The hybrid furnace 10 may advantageously have at the bottom a bubbler (not shown), i.e. a system for injecting at least one gas, such as air or nitrogen, located, for example, in the melting zone 100, the bubbles of which then cause the glass to move upwards.

[0164] The melting zone 100 of the hybrid furnace 10 is bounded downstream by a “no-return” separator 170 that is configured to prevent molten glass from returning to said melting zone 100 having a first convection current (C1).

[0165] In this first embodiment, the “no-return” separator 170 consists of a wall 120 , referred to as the first wall, which is located downstream of the melting zone 100 of the hybrid furnace 10 .

[0166] Thus, as shown in Figures 1 and 2, a first wall 120 defines a melt zone 100 having a first convection current (C1), said wall 120 preferentially extending across the entire width of the melt zone 100 in the short direction from one wall to the other.

[0167] Furthermore, the melting zone 100 is connected to the refining zone 200 by a longitudinally and linearly extending wall such that said zones 100 and 200 have the same width.

[0168] Preferably, at least a portion of the electrode 110 is positioned adjacent the first wall 120 that defines the downstream melt zone 100, and the electrode 110 is positioned within a downstream portion of the melt zone 100 that extends partway through the length of the melt zone.

[0169] Depending on their number, for example equal to six in FIGS. 1 and 2, the electrodes 110 are preferentially arranged over more than two thirds of said length.

[0170] According to a second aspect of the invention, refining zone 200 has a second convection stream (C2), referred to as the upstream recycle stream, and a third convection stream (C3), referred to as the downstream recycle stream.

[0171] The glass refining zone 200 comprises a first refining zone 210 and a second refining zone 220 , said first refining zone 210 advantageously comprising at least one burner 205 , or even two burners, and an electrode 230 .

[0172] The number and locations of burners 205 and electrodes 230, respectively, shown in Figures 1 and 2 are purely illustrative and therefore non-limiting in nature.

[0173] First refining zone 210 is separated from melting zone 100 by a first wall 120 and from second refining zone 220 by a second wall 240 , which respectively form a “no-return” separator 170 .

[0174] In the refining zones 200 of the hybrid furnace 10, the glass thus recirculates in the first refining zone 210 in a counterclockwise direction following the second convection current (C2) and in the second refining zone 220 in a clockwise direction following the third convection current (C3).

[0175] Advantageously, first wall 120 is configured to prevent glass from returning from first refining zone 210 back to melting zone 100, thereby isolating melting zone 100 and first refining zone 210 from one another.

[0176] Advantageously, the first convection current (C1) in the melting zone 100 is separated from the second convection current (C2) in the first refining zone 210, thus making it possible to control each of said flows C1, C2 independently of each other.

[0177] Advantageously, the first wall 120 is configured to restrict the amount of glass passing from the melting zone 100 to the first refining zone 210 , thereby, among other things, increasing the residence time of the glass in the melting zone 100 .

[0178] In fact, the first wall 120 extends vertically from the bottom 108 of the furnace for a given height, with its top immersed below the surface (S) of the glass.

[0179] In the hybrid furnace 10 , glass is conveyed from the melting zone 100 over a first wall 120 into a first refining zone 210 .

[0180] Thus, in addition to preventing any return by separating the flows C1 and C2, the height of the first wall 120 also determines the passage of glass from the melting zone 100 to the first refining zone 210.

[0181] Thanks to the first wall 120, the melting zone 100 can be controlled independently of the first refining zone 210, particularly by selectively controlling the electrode 110 to control the first convection current (C1).

[0182] Indeed, the positioning of the electrode 110 immersed in the downstream portion of the melting zone 100 enables the burner 105 to create a relatively hot spot there in the glass bath 106 relative to the upstream portion, where the burner 105 is positioned above the surface of the bath 106 covered by the glass batch 104.

[0183] Advantageously, the electrodes 110 also make it possible to regulate the temperature of the glass passing from the melting zone 100 to the first refining zone 210 .

[0184] Similar to the first wall 120, the second wall 240 extends vertically for a predetermined height from the bottom 208 of the first refining zone 210 of the furnace, with the top immersed below the surface (S) of the glass that determines the portion of the glass that passes from the first refining zone 210 to the second refining zone 220 of the refining zone 200.

[0185] Advantageously, the second wall 240 is configured to prevent glass from returning from the second refining zone 220 to the first refining zone 210, so that the second convection current (C2) and the third convection current C3 in the first refining zone 210 are separated and can be controlled independently of each other.

[0186] Similar to the first wall 120, the second wall 240 advantageously allows for a longer residence time of the glass in the first refining zone 210, which directly contributes to obtaining high quality glass.

[0187] Preferably, the base 208 is flat. As shown in Figure 1, the hybrid furnace 10 has at least one change in the depth of the base relative to the surface S of the glass.

[0188] Preferably, the hybrid furnace 10 has, for example, a raised portion of the bottom 208 of the first refining zone 210 relative to the bottom 108 of the melting zone 100, such that the depth P1 of the glass in the first refining zone 210 is smaller than the depth P of the glass in the melting zone 100.

[0189] Advantageously, the electrodes 230 of the first refining zone 210 and said at least one burner 205 are capable of heating the glass to a temperature of more than 1450°C.

[0190] Thanks to the first wall 120 and the second wall 240, the first refining zone 210 is separated from the melting zone 100 and from the second refining zone 220, respectively, and isolated from the other without any return, so that the first refining zone 210 can be independently controlled.

[0191] Thus, the hybrid furnace 10 has three streams C1, C2, C3, each independent of the other.

[0192] In the first refining zone 210 , an electrode 230 immersed in the glass makes it possible to bring the glass to a temperature that is determined solely on the basis of refining, and in particular independently of the melting zone 100 .

[0193] In fact, due to the lack of return and the separation between the first convection current C1 and the second convection current C2, the heat provided by the electrode 230 is used exclusively for purification and, by doing so, is advantageously used in an optimal manner.

[0194] Similarly, the heat provided by burner 105 and auxiliary electrode 110 in melting zone 100 is intended for the glass melting process and would need to be taken into account for the refining process without it.

[0195] Advantageously, the temperature of the melting zone 100 and the temperature of the first refining zone 210 may be controlled independently of each other.

[0196] Preferably, in the first glass refining zone 210, heat is provided primarily by the electrodes 230, with the at least one burner 205 only intervening in a supplementary manner, and thus electrical energy dominates over fuel energy in providing heat, unlike in the melting zone 100.

[0197] Alternatively, the first glass refining zone 210 has only burners and no electrodes 230, and the glass is heated only at the surface.

[0198] Nonetheless, electrodes 230 are advantageous due to their heating efficiency; because said electrodes 230 are directly immersed in the molten glass originating from melting zone 100 .

[0199] Preferably, electrodes 230 here are longer than electrodes 110, eg, thereby further improving heating of the glass in first refining zone 210 by increasing the surface area for heat exchange with the glass.

[0200] The at least one burner 205 is positioned within the refining zone 200 to obtain a surface hot spot (or point source) that defines a reversal zone 250 between the second convection current C2 and the third convection current C3.

[0201] Preferably, the hybrid furnace 10 has another change in the depth of the bottom relative to the surface (S) of the glass between the first refining zone 210 and the second refining zone 220, more precisely a raised portion of the bottom 228 of the second refining zone 220.

[0202] Thus, as shown in FIG. 1, the glass depth P2 in the second refining zone 220 is less than the glass depth P1 in the first refining zone 210.

[0203] According to a third aspect of the invention, the glass cooling zone 300 comprises an equalization tank 310 through which the third convection current (C3) flows.

[0204] Advantageously, the equalization tank 310 of the cooling zone 300 comprises, from upstream to downstream, a neck 320, ie a zone of reduced width as shown in FIG.

[0205] The passage from the second refining zone 220 to the neck 320 is achieved by abruptly narrowing the width and passing volume of the glass, for example here by walls 322 and 324 which form an angle of 90° with the longitudinal median axis A-A' of the furnace.

[0206] Alternatively, the angle at the entrance of the neck 320 may have a value greater than 90°, so that the narrowing is less abrupt and more gradual.

[0207] The passage from neck 320 to conditioner 330 is achieved by an abrupt widening of the passing portion of the glass, for example here by walls 323 and 325 which form an angle of 90° with the longitudinal median axis A-A' of the furnace.

[0208] Similarly, the value of the angle at the outlet of the neck 320 may be selected so that the widening is relatively gradual, rather than relatively abrupt, in the longitudinal medial axis A-A' of the furnace.

[0209] Advantageously, the atmosphere of the refining zone 200 and the relatively cool atmosphere of the cooling zone 300 are separated from each other by a heat screen 340, e.g. a partition, which extends vertically from the crown in the cooling zone 300 to the vicinity of the surface S of the glass, preferentially without being submerged in the glass.

[0210] Preferably, the hybrid furnace 10 further comprises another change in the depth of the base relative to the surface (S) of the glass between the second refining zone 220 and the cooling zone 300 .

[0211] Preferably, the hybrid furnace 10 has a first raised portion of the bottom 328 of the neck 320 relative to the bottom 228 of the second refining zone 220. Thus, the glass depth P3 at the neck 320 is less than the glass depth P2 at the second refining zone 220.

[0212] Advantageously, the bottom 228 of the second refining zone 220 is joined to the bottom 328 of the neck 320 by a segment 252, which is inclined to ensure a gradual passage of the glass from depth P2 to depth P3.

[0213] Preferably, the hybrid furnace 10 has a second raised portion of the bottom 338 of the conditioner 330 relative to the bottom 328 of the neck 320. Thus, the glass depth P4 in the conditioner 330 is smaller than the glass depth P3 in the neck 320.

[0214] Advantageously, the bottom 328 of the neck 320 is joined to the bottom 338 of the regulator 330 by a segment 353, which is sloped to ensure a gradual passage from depth P3 to depth P4.

[0215] Preferably, the glass depth in the hybrid furnace 10 decreases continuously from upstream to downstream, from the melting zone 100 to the conditioner 330 of the cooling zone 300 .

[0216] However, the raised portion of the bottom of the hybrid furnace 10 just described with reference to the embodiment shown by Figures 1 and 2 is only one example of a depth variation, which may alternately have one or more level differences.

[0217] Preferably, the second refining zone 220 has an electrode 260 that is immersed in the glass. Alternatively, the electrode 260 is replaced by at least one burner.

[0218] The number and locations of electrodes 260 shown in Figures 1 and 2 are purely illustrative and therefore completely non-limiting.

[0219] Advantageously, the electrodes 260 of the second refining zone 220 are selectively controlled to control a third convection current (C3) which the glass follows as it recirculates in a clockwise direction.

[0220] In fact, the third convection current (C3) extends longitudinally from the second refining zone 220 to the regulator 330 and also passes through the entire cooling zone 300, so that the heat supply from only the glass collected in the first refining zone 210 may be insufficient.

[0221] An electrode 260 is advantageously immersed in the glass and placed in the second refining zone 220, thus making it possible to create a hot spot upstream, thereby controlling a third convection current (C3), referred to as the downstream recirculation flow.

[0222] As explained above, due to the configuration of the second wall 240, glass does not return from the second refining zone 220 to the first refining zone 210; the second convection current (C2) can be controlled independently of the third convection current (C3).

[0223] Advantageously, electrode 260 also contributes to the completion of the refining that takes place in first refining zone 210 .

[0224] The equalization tank 310 is connected to a flow path 400 downstream of the regulator 330 .

[0225] Advantageously, after the equalization tank 310, there is no return flow in the flow path 400 intended to supply glass to the forming zone; in other words, the flow of glass in the flow path 400 is a "piston" type flow.

[0226] Advantageously, the hybrid furnace 10 is capable of supplying a float unit for floating the glass on a bath of molten metal with high quality glass, i.e. glass with less than 0.1 bubbles per liter, at a take-off rate of more than 400 tonnes per day, preferentially 600-900 tonnes per day and even more than 1000 tonnes per day.

[0227] Advantageously, the hybrid furnace 10 according to the invention is capable of delivering high quality glass with less than 0.1 bubbles per litre, or even preferentially less than 0.05 bubbles per litre.

[0228] Advantageously, such high quality glass is most particularly suitable for feeding into a float unit for floating the glass onto a bath of molten metal intended to produce flat glass.

[0229] The present invention also relates to a method for producing glass in a hybrid furnace 10, such as the embodiment described with reference to FIGS.

[0230] The manufacturing method includes the following steps: (a) - Melting a glass batch in a hot crown melting zone 100 having a first convection current C1 of glass; (b) - refining the glass in a first refining zone 210 with a second convection current (C2) and then in a second refining zone 220 with a third convection current (C3), said first refining zone 210 being separated from the melting zone 100 and from the second refining zone 220, respectively, and thus being controllable independently of each other; (c) - Cooling the glass in a cooling zone 300, formed by an equalization tank 310, through which said third convection current (C3) flows.

[0231] Advantageously, the method comprises a step (a1) of controlling an auxiliary electrode 110 placed in the melting zone 100 to control said first convection current (C1) of glass.

[0232] Electrodes 110 are selectively controlled to regulate the temperature of the glass passing from the melting zone 100 to a first refining zone 210 .

[0233] Advantageously, the first convection current (C1), which in this first embodiment is formed by the first wall 120 and separated by the separation device 170, is controlled independently of the second convection current (C2) of the first purification zone 210.

[0234] Advantageously, the method comprises a step (b1) of controlling an electrode 230 placed in the first refining zone 210 to control said second convection current (C2) of glass.

[0235] Advantageously, the second convection flow (C2) of glass, separated by the second wall 240, is controlled independently from the third convection flow (C3) of the second refining zone 220.

[0236] Advantageously, the method comprises a step (b2) of controlling said third convection current (C3) of glass by controlling heating means, at least one burner and / or electrodes, preferentially electrode 260 here, arranged in the second refining zone 220.

[0237] Advantageously, electrodes 260 are selectively controlled to regulate the temperature of the glass in said second refining zone 220 of refining zone 200 .

[0238] In the hybrid furnace 10 according to the invention, the contribution made by electrical energy in the supply of heat by the electrodes 110, 230 and 260 is advantageously more than 40% of the total heat supplied to the furnace.

[0239] The design of the hybrid furnace 10 according to the present invention advantageously allows for close control over the melting, refining, and cooling steps of the glass production process, thereby ensuring energy efficiency.

[0240] Thanks to the first wall 120 and the second wall 240 forming the separator 170, each configured to prevent any return, the melting, refining and cooling zones are advantageously separated from each other, thus making it possible to control each convection independently from the convection located downstream.

[0241] Advantageously, the design of the hybrid furnace 10 allows the energy efficiency of the furnace to be optimized by providing as close as possible to the exact amount of heat required for each step of the glass manufacturing process, thereby improving the carbon footprint.

[0242] A second embodiment of a hybrid reactor 10 according to the present invention, as shown in FIGS. 3 to 5, will be described below in comparison with the first embodiment shown in FIGS.

[0243] In this second embodiment, the burners 105 are also three in number and are preferentially placed upstream, near the charging opening 102 for the glass batch 104. However, the number of electrodes 110 here is nine, as shown in figures 3 and 4.

[0244] Advantageously, the heat provided by the electrodes 110, as an auxiliary to the burners 105, represents at least 40% of the total heat of the melting process carried out in the melting zone 100, and preferentially between 50 and 70%.

[0245] However, it is recalled that in general the number of burners or electrodes is purely exemplary and therefore completely non-limiting.

[0246] Preferably, the melting electrodes 110 are distributed evenly across the length of the melting zone 100 .

[0247] Advantageously, the electrodes 110 are arranged mainly in the downstream part of the melting zone 100, especially taking into account that here they are greater in number (equal to 9 instead of 6), and in the two-thirds part of said melting zone 100 extending over its length (L).

[0248] According to one feature of this second embodiment, the hybrid furnace 10 has a neck 160, called the first neck, connecting the melting zone 100 to the refining zone 200, more specifically to the first refining zone 210.

[0249] Advantageously, said first neck 160 of the hybrid furnace makes it possible to ensure the cooling of the glass as it flows from the melting zone 100 to the first refining zone 210 of the refining zone 200 of the glass.

[0250] The cooling of the glass is greater the longer the first neck 160 is; because the glass from the melting zone 100 naturally cools as it flows from upstream to downstream through the first neck 160.

[0251] Preferably, the first neck 160 has a length configured to obtain a reduction in the temperature of the molten glass that is intended to subsequently flow into the first refining zone 210 .

[0252] As mentioned above, the molten glass will have a higher temperature in the melting zone 100 when more heat is provided by the electrodes 110 .

[0253] Advantageously, the hybrid furnace 10 comprises glass cooling means 500 capable of selectively cooling the glass in the first tank neck 160 .

[0254] In addition to the cooling of the glass as it flows through the first neck 160 connecting the melting zone 100 to the first refining zone 210, the cooling means 500 make it possible to further increase the cooling and in particular to vary this cooling, whereby an adjustment of the temperature of the glass is then advantageously obtained.

[0255] Preferably, the means 500 for cooling the glass in the first neck 160 comprises at least one air circulation cooling device 510 .

[0256] An exemplary embodiment of the cooling device 510 will be described below as shown more particularly diagrammatically in Figures 6 and 7, which respectively illustrate a third embodiment and a variant, and reference will therefore advantageously be made to said figures.

[0257] When the hybrid furnace 10 has such an air cooling device 510 in the first neck 160, the hybrid furnace 10 has at least one separation means 174 for separating the atmosphere of the melting zone 100 from the atmosphere of the first neck 160.

[0258] Exemplary embodiments of such atmosphere isolation means 174 are shown in Figures 6 and 7 above and described in more detail below.

[0259] Such an air cooling device 510 for glass comprises, for example, at least suction means 512 for introducing cooling air into the atmosphere of said first neck 160 of the hybrid furnace 10 .

[0260] Preferably, the device 510 for cooling the glass comprises exhaust means 514 arranged in the first neck 160 for exhausting the hot air and ensuring its renewal by fresh cooling air.

[0261] Alternatively, the discharge means are formed by extraction means (not shown), located downstream of the first neck 160 and intended to extract the exhaust gases, and advantageously, the hot air is discharged together with the exhaust gases by said extraction means, without the hybrid furnace 10 having to be equipped with additional means.

[0262] The air intake means 512 and the air exhaust means 514 of the glass cooling device 510 are formed, for example, by one or more openings opening into the battlement supporting the crown of the first neck 160 .

[0263] As shown diagrammatically in Figures 6 and 7, the at least one suction 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 the upstream portion of the first neck 160, while the one or more exhaust openings are located in the downstream portion of the first neck 160.

[0264] The air intake means 512 and the air exhaust means 514 are arranged, for example, on either side of the first neck 160 in the transverse direction, or alternatively on only one side of the first neck 160 .

[0265] Advantageously, the temperature of the cooling air introduced into the first neck 160 is lower than the temperature of the hot air located inside said first neck 160, and the circulating cooling air forms a heat transfer fluid.

[0266] Preferably, the cooling air used is atmospheric air collected outside the hybrid furnace 10 or even outside the building enclosure in which said hybrid furnace 10 is installed, supplying the float unit.

[0267] Advantageously, the temperature of the atmospheric air used is controlled and thereby regulated; the air may for example be pre-cooled or pre-heated before introduction, thereby controlling its temperature.

[0268] The glass is cooled mainly by convection, the cooling air introduced is heated, particularly under contact with the surface of the glass, and is then removed together with the heat (calories) transferred by the glass.

[0269] Advantageously, the circulation of air can be controlled by air blowing means (not shown), such as a fan, associated with said intake means 512 and / or exhaust means 514 and which can be controlled to vary the flow rate of the circulating air.

[0270] Advantageously, the glass manufacturing method according to the invention comprises a step of regulating the cooling of the glass in the first neck 160, in particular by selectively controlling glass cooling means 500, such as at least one air cooling device 510 according to the embodiment previously described.

[0271] Advantageously, the amount of cooling air introduced into the first neck 160 by the suction means 512 of the air cooling device 510 is controlled based in particular on the temperature of the glass.

[0272] Alternatively, or in combination with the air cooling device 510, the hybrid furnace 10 has a glass cooling means 500, which is immersed in the glass flowing from upstream to downstream through the first neck 160, thereby enabling its cooling.

[0273] Such cooling means 500 are for example formed by vertical studs immersed in the glass, cooled by a cooling circuit containing a heat transfer fluid, thereby dissipating the heat transferred by the glass to the studs.

[0274] According to another exemplary embodiment, the cooling means 500 are capable of cooling the structure of the first neck 160 which is in contact with the glass, the cooling being performed from outside the structure of the first neck 160 .

[0275] Of course, the cooling means 500 associated with the first tank neck 160, such as those according to the various embodiments described above, may be implemented alone or in combination.

[0276] Advantageously, the means for cooling the glass associated with the first neck 160 allows for selective control of the temperature of the glass, which is likely to vary, particularly when the removal rate varies; this is because an increase in the removal rate causes the temperature of the glass to increase.

[0277] In comparison with such glass cooling means associated with the first neck 160, such variable cooling of the glass would not be possible at the throat.

[0278] Preferably, the passage from the melting zone 100 to the first neck 160 is achieved by an abrupt narrowing of the width and cross section of the glass passing portion, for example by walls 162 and 163, which here form an angle of 90° with the central longitudinal axis A-A' of the furnace.

[0279] Preferably, the passage from the first neck 160 to the glass refining zone 200 is accomplished 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.

[0280] Alternatively, the angle at the inlet of the first neck 160 may have a value greater than 90°, thereby resulting in a relatively gradual, rather than abrupt, narrowing in width; similarly, the value of the angle at the outlet of the first neck 160 may be selected so as to result in a relatively gradual, rather than abrupt, widening along the central longitudinal axis A-A' of the furnace.

[0281] Advantageously, the molten glass flowing from upstream to downstream through the first neck 160 is collected following the first flow (C1) after passing through the lower part of the melting zone 100 where the electrode 110 is located.

[0282] Advantageously, by comparison, the first neck 160 is less susceptible to wear caused by the continuous flow of molten glass than the throat, where all refractory elements of the substructure are in contact with the glass flowing from upstream to downstream at the withdrawal velocity.

[0283] Indeed, in the first neck 160, a portion of the flowing glass is in contact with the atmosphere through the surface S.

[0284] According to a variant not shown in FIGS. 3 to 5, the hybrid furnace 10 comprises atmosphere separation means for separating the atmosphere of the melting zone 100 from the atmosphere of the refining zone 200.

[0285] Such atmosphere separation means are for example similar to those provided below with reference numeral "174" with reference to Figures 6 and 7, said atmosphere separation means being formed by a partition (or curtain).

[0286] The first neck 160 has a bottom which is marked with the reference numeral 165 in Figures 3 to 5. In this second embodiment, the separating device 170 consists of at least one raised portion 161 of the bottom 165 of said first neck 160.

[0287] In comparison with the first wall 120, the ridge 161 is formed directly by the bottom 165 and is not attached to it, and therefore the ridge 161 consists of the fire-resistant material of the underlying structure forming the bottom 165 of the first neck 160.

[0288] Advantageously, the at least one ridge 161 is less susceptible to wear than the first wall 120, which is a narrow and thin structure.

[0289] Advantageously, the at least one ridge 161 is wide in that it extends longitudinally over a major portion of the length of the first neck 160, and the ridge 161 advantageously contributes to cooling of the glass within the first neck 160.

[0290] As shown in more detail in FIG. 5, the raised portion 161 has at least a first ascending segment 164, a second apex segment 166, and a third descending segment 168, successively from upstream to downstream.

[0291] Advantageously, the ridge 161 extends in the transverse direction across the entire width of the first neck 160, from one longitudinal wall to the other.

[0292] Of course, such a protuberance 161 may have numerous geometric variations with regard to its general shape and dimensions, depending in particular on the respective configurations of the different portions 164, 166 and 168 which form it.

[0293] FIG. 5 shows in detail the first neck 160 of the hybrid furnace 10 according to the second embodiment of FIG. 3, thereby illustrating an example of said at least one ridge 161 .

[0294] Preferably, the rise segment 164 is inclined at an angle (α) determined to form a ramp that can cause the molten glass to rise toward the top segment 166 of the ridge 161 .

[0295] Preferably, the upward segment 164 is an inclined surface having an acute angle (α), for example, of 20° to 70°, said angle (α) being indicated as the angle between the upward segment 164 of the ridge 161 and the horizontal, here taken as the reference point for the flat bottom 108 of the melt zone 100.

[0296] As a variant (not shown), the ascending segment 164 may be stepped, for example in the form of a staircase having at least one step, or even two or more steps, which may or may not be identical in height and / or length dimensions.

[0297] Preferably, the top segment 166 is planar, forming a horizontal plateau, and therefore advantageously extends longitudinally over a given length, here preferably over half or more of the total length of the first neck 160.

[0298] The apex segment 166 determines the maximum height H′ that the ridge 161 has, and thereby also determines the depth P′ relative to the surface S of the glass, ie, the passing portion 180 of the molten glass within the first neck 160 .

[0299] Preferably, the descending segment 168 of the ridge 161 extends vertically and is connected by a right angle (β) to the downstream end of the top segment 166, which extends horizontally and has a flat upper surface.

[0300] As shown in FIG. 7, described below, according to another embodiment, the descending segment 168 is configured to gently entrain the flow of molten glass from the first neck 160 into the refining zone 200 .

[0301] Such a portion 168 is formed, for example, by an inclined plane, which may or may not have a step, in particular in the form of a staircase as described above for the alternative embodiment of the ascending segment 164.

[0302] Thus, in this second embodiment, the separation device 170 is formed by at least the above-mentioned raised portion of the bottom 165, this raised portion 161 providing the same function as that of the wall 120 of the first embodiment, or even of the two walls in the case of the embodiment not shown.

[0303] In a variant not shown, the separation device 170 has at least one barrier that extends vertically and is partially immersed in the glass bath 106 flowing through the first neck 160 from the melting zone 100 to the glass refining zone 200, said barrier being configured to prevent the molten glass from returning from the refining zone 200 to the melting zone 100.

[0304] Preferably, the barrier is thus located at the upstream end of the first neck 160 .

[0305] The use of such a barrier is described in patent application EP-21306609.5, filed on November 18, 2021 in the name of the applicant, which relates to a hybrid furnace of a different design including a cold crown electric melting zone.

[0306] According to the teachings of this application, such a barrier can itself constitute a separation device 170 within the meaning of the present invention.

[0307] Advantageously, such a barrier may also be used in combination with the raised portion 161 of the bottom portion 165 according to the second embodiment.

[0308] Thus, the (non-return) separation device 170 may consist of a barrier and / or a raised portion 161 at the bottom 165 of the first neck 160 .

[0309] FIG. 6 shows such an alternative embodiment, which is illustrated by comparison with FIG.

[0310] According to this variant, the hybrid furnace 10 comprises a separation device 170 having a barrier 172 associated with said at least one raised portion 161 of the bottom 165 of the first neck 160 .

[0311] Advantageously, the barrier 172 contributes to the cooling of the glass in the first neck 160 by restricting the flow in the first neck 160 and by means of a cooling circuit containing a heat transfer fluid of the "water jacket" type, which makes it possible to discharge part of the heat (calories) transferred by the glass to the barrier 172.

[0312] As shown in FIG. 6, the barrier 172 extends vertically and is partially immersed in the glass bath 106 that flows through the first neck 160 from the melting zone 100 to the glass refining zone 200 .

[0313] Preferably, the barrier 172 is disposed above the top segment 166 of the raised portion 161 at the bottom 165 of the first neck 160 .

[0314] Advantageously, the barrier 172 is mounted so as to be vertically movable, thereby allowing adjustment of its immersion depth in the glass bath 106, thereby varying the passing portion 180 of the molten glass based on adjusting the depth of the barrier 172; in the absence of the barrier 172, the passing portion would by default correspond to a glass depth P'' determined by the at least one ridge 161 having a predetermined height H''.

[0315] Preferably, the height H'' here is smaller than the height H', and therefore the depth P'' is greater than the depth P'.

[0316] Advantageously, the barrier 172 is removable, ie dismantlable, thereby allowing it to be replaced, particularly when worn, facilitating maintenance of the furnace.

[0317] As mentioned above, the hybrid furnace 10 advantageously comprises a separating means 174, such as a curtain, for separating the atmosphere of the melting zone 100 from the atmosphere of the refining zone 200.

[0318] Advantageously, such a separating means 174 makes it possible to isolate the atmosphere of the first neck 160 from that of the melting zone 100, especially when an air cooling device is implemented as the means for cooling the glass in the first neck 160.

[0319] Advantageously, the hybrid furnace 10 has a blocking means 176 (also called a "skimmer"), which is arranged at the downstream end of the melting zone 100 and can, if necessary, retain a portion of the glass batch layer 104 within the melting zone 100, thereby ensuring that said glass batch present at the surface of the glass bath 106 does not enter the refining zone 200.

[0320] As shown in FIG. 6, the blocking means 176 is formed by a separation 174, the free end of which extends at the surface of the bath 106 or is immersed in the glass bath 106.

[0321] FIG. 7 shows another alternative embodiment which will be described in comparison with FIG.

[0322] In this variant, the blocking means 176 is structurally separate from said separating means 174, and said blocking means 176 can be attached to the separating means 174 or can be separate from the separating means 174, as shown in FIG.

[0323] Compared to the variant of Figure 6, the "non-return" separation device 170 is here formed by only one ridge 161, said ridge 161 at the bottom 165 of the first neck 160 having a height H' that determines a depth P', similar to the embodiment of Figures 3 to 5 which does not implement a barrier 172.

[0324] The alternative embodiment according to FIG. 7 also shows a different shape of the ridges 161 compared to those of the embodiment of FIGS.

[0325] Indeed, in this variation, the downstream segment 168 is configured to gently entrain the flow of molten glass toward the refining zone 200 .

[0326] Such a portion 168 is thus formed by an inclined plane, which may or may not be stepped, in particular in the form of a staircase.

[0327] Preferably, portion 168 is inclined at an angle (β) determined to form a ramp that allows the molten glass to descend gradually toward bottom 208 of refining zone 200 .

[0328] For the descending segment 168, the angle (β) is an obtuse angle that may have a value of, for example, 90° to 145°, and said angle (β) corresponds to the interior angle noted in FIG. 7 at the point where the top segment 166 joins with the descending segment 168.

[0329] As a variant (not shown), the segments 168 are not flat but have steps, for example in the form of a staircase having at least one step, or even two or more steps, which may or may not be identical in height and / or length dimensions.

[0330] As shown by the figure, the depth of the glass here is not the same between the depth P in the melting zone 100 and that in the refining zone 200 on either side of the at least one ridge 161, respectively, but rather it may have at least one depth variation.

[0331] As indicated above, such a protuberance 161 may have numerous geometrical variations with regard to its general shape, its dimensions and in particular depending on the respective configurations of the different portions 164, 166 and 168 which form it.

[0332] In the embodiment illustrated by figures 3 to 7, the hybrid reactor 10 advantageously has a first neck 160 in which said separating device 170 is arranged.

[0333] According to these embodiments, the invention more particularly proposes a hybrid glass production furnace 10 for feeding a float unit for floating glass on a bath of molten metal, said hybrid furnace 10 comprising, from upstream to downstream: a hot crown melting zone 100, comprising at least several burners 105 capable of melting a glass batch 104 to obtain a glass bath 106, said melting zone 100 having a first convection current C1, a neck 160, called the first neck, connecting said melting zone 100 to the glass refining zone 200 and having a "no-return" separator 170 configured to prevent the molten glass from returning to the melting zone 100; - said glass refining zone 200 comprising a first refining zone 210 with at least one burner 205 and an electrode 230, and a second refining zone 220, said first refining zone 210 being separated from the melting zone 100 by said separating device 170 and from the second refining zone 220 by a wall 240, respectively, and glass being recirculated in the first refining zone 210 on a second convection current C2 and in the second refining zone 220 on a third convection current C3; and a glass cooling zone 300 comprising an equalization tank 310 through which said third convection current C3 flows.

Claims

1. 1. A hybrid glass making furnace (10) for feeding a float unit for floating glass on a bath of molten metal, the hybrid furnace (10) comprising, from upstream to downstream: a hot crown melting zone (100) comprising at least several burners (105) capable of melting a glass batch (104) to obtain a glass bath (106), said melting zone (100) having a first convection current (C1) and being bounded by a "no-return" separator (170) configured to prevent molten glass from returning into said melting zone (100); a glass refining zone (200) comprising a first refining zone (210) with at least one burner (205) and an electrode (230), and a second refining zone (220), the first refining zone (210) being separated from the melting zone (100) by the separating device (170) and the second refining zone (220) by a wall (240), and the glass being recirculated in the first refining zone (210) on a second convection current (C2) and in the second refining zone (220) on a third convection current (C3); and a glass cooling zone (300) comprising an equalization tank (310) through which the third convection current (C3) flows, A furnace having:

2. 2. The furnace of claim 1, wherein the separation device (170) is capable of preventing the glass from returning from the first refining zone (210) to the melting zone (100), such that the first convection flow (C1) in the melting zone (100) can be controlled independently from the second convection flow (C2) in the first refining zone (210).

3. 3. The furnace of claim 1, wherein the separator (170) is configured to limit the amount of glass passing from the melting zone (100) to the first refining zone (210), thereby increasing the residence time of the glass in the melting zone (100).

4. 3. The furnace of claim 1, wherein the separation device (170) comprises a wall (120), referred to as a first wall, configured to prevent the molten glass from returning from the refining zone (200) to the melting zone (100).

5. 3. The hybrid furnace (10) according to claim 1 or 2, wherein the hybrid furnace (10) has a neck (160), called the first neck, connecting the melting zone (100) to the refining zone (200).

6. 6. The hybrid furnace (10) according to claim 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 neck (160).

7. 6. The furnace of claim 5, wherein the first neck (160) has a bottom (165), and the separation device (170) has at least one ridge (161) on the bottom (165) of the first neck (160), the ridge configured to prevent the molten glass from returning from the refining zone (200) to the melting zone (100).

8. 8. The furnace of claim 7, wherein the at least one raised portion (161) of the bottom portion (165) has, from upstream to downstream, at least one ascending segment (164), a top segment (166), and a descending segment (168).

9. 9. The furnace of claim 8, wherein at least one of the ascending segment (164) and the descending segment (168) of the at least one raised portion (161) of the bottom (165) is inclined relative to the horizontal and / or has a top segment (166) forming a plateau.

10. 8. The furnace of claim 7, wherein the raised portion (161) has a maximum height (H', H'') that determines in whole or in part a passage portion (180) of the molten glass within the first neck (160).

11. 6. The furnace of claim 5, wherein the separation device (170) comprises at least one barrier (172) extending vertically and partially immersed in the glass bath (106) flowing from the melting zone (100) to the glass refining zone (200) through the first neck (160), the barrier (172) configured to prevent the molten glass from returning from the refining zone (200) to the melting zone (100).

12. The furnace of claim 11, wherein the barrier (172) is disposed at an upstream end of the first neck (160).

13. A furnace as described in claim 11, wherein the first neck (160) has a bottom (165), the separation device (170) has at least one raised portion (161) on the bottom (165) of the first neck (160), the raised portion configured to prevent the molten glass from returning from the refining zone (200) to the melting zone (100), and the separation device (170) has the barrier (172) and the at least one raised portion (161) on the bottom (165) of the first neck (160).

14. A furnace as described in claim 13, wherein the at least one raised portion (161) of the bottom (165) has, from upstream to downstream, at least one ascending segment (164), a top segment (166), and a descending segment (168), and the barrier (172) is located above the top segment (166) of the raised portion (161) of the bottom (165) of the first neck (160).

15. 12. The furnace of claim 11, wherein the barrier (172) is mounted to be vertically movable, thereby allowing for adjustment of its immersion depth into the glass bath (106), thereby varying the passing portion (180) of the molten glass based on adjustment of the depth of the barrier (172).

16. 3. The hybrid furnace (10) of claim 1 or 2, wherein the hybrid furnace (10) comprises separating means (174), such as a curtain, for separating the atmosphere of the melting zone (100) from the atmosphere of the refining zone (200).

17. 3. The hybrid furnace of claim 1, wherein the hybrid furnace has a blocking means capable of retaining a layer of glass batch present on a surface of the glass bath in the melting zone, the blocking means being disposed at a downstream end of the melting zone.

18. A furnace as described in claim 17, wherein the hybrid furnace (10) has a separating means (174), such as a curtain, for separating the atmosphere of the melting zone (100) from the atmosphere of the refining zone (200), and the blocking means (176) is formed by the separating means (174), the free end of which extends on the surface of the bath (106) or is immersed in the glass bath (106).

19. A furnace as described in claim 17, wherein the hybrid furnace (10) has a separation means (174), such as a curtain, for separating the atmosphere of the melting zone (100) from the atmosphere of the refining zone (200), 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).

20. 3. The furnace according to claim 1 or 2, wherein the hybrid furnace (10) is configured to supply a float glass unit with high quality glass having less than 0.1 bubbles per liter, preferentially less than 0.05 bubbles per liter, at a take-off rate of at least 400 tonnes per day, preferentially 600-900 tonnes per day, or even 1000 tonnes per day or more.

21. 3. The furnace of claim 1 or 2, wherein the melting zone (100) comprises an electrode (110) immersed in the glass bath (106) and having auxiliary electrical heating means.

22. The furnace of claim 21, wherein the electrode (110) is disposed in a downstream portion of the melting zone (100).

23. 22. The furnace of claim 21, wherein the electrodes (110) of the melting zone (100) are selectively controlled to control the first convection current (C1) in the melting zone (100).

24. 3. The furnace of claim 1 or 2, wherein the electrodes (230) and the at least one burner (205) of the first refining zone (210) are capable of heating the glass to a temperature above 1450°C.

25. 3. The furnace according to claim 1, wherein the at least one burner (205) is arranged in the refining zone (200) to obtain a hot spot at the surface that determines a reversal zone (250) between the second convection current (C2) and the third convection current (C3).

26. 3. The furnace of claim 1, wherein the electrodes (230) of the first refining zone (210) are selectively controlled to control the second convection (C2) within the first refining zone (210).

27. 3. The furnace of claim 1, wherein the wall (240) is configured to prevent the glass from returning from the second refining zone (220) to the first refining zone (210), so that the second convection current (C2) in the first refining zone (210) can be controlled independently of the third convection current (C3).

28. 3. The furnace of claim 1, wherein the wall is configured to restrict the amount of glass passing from the first refining zone to the second refining zone, thereby increasing the residence time of the glass in the first refining zone.

29. 3. The furnace of claim 1, wherein the second refining zone (220) comprises an electrode (260) immersed in the glass and capable of selectively controlling the third convection current (C3).

30. 3. The furnace according to claim 1, wherein the equalization tank (310) of the cooling zone (300) has, from upstream to downstream, a neck (320), referred to as a second neck, followed by a regulator (330).

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