Gas-cooled electrode holder

Abstract

The invention relates to an electrode holder (10) intended to hold an electrode (50) which extends along a main axis (X) through a window (101) of a container (100), the electrode holder (10) comprising: a casing (11), which extends along the main axis, and a first hollow portion (12), a second hollow portion (13) and a fastening interface (14), which physically and fluidically separates the first and second hollow portions, wherein • the first hollow portion (12) is intended to house the electrode, one end (51) of the electrode (50) being intended to be fastened to the fastening interface (14), and wherein • the second hollow portion (13) comprises a gas feed opening (15), a cooling duct (16) extending along the main axis and at least one orifice (17) passing through the casing; and a pushing mechanism (18), which is configured to apply a pushing force to the second hollow portion (13) along an axis parallel to the main axis.

Description

[0001] DESCRIPTION

[0002] Title of the invention: Gas-cooled electrode holder

[0003] The invention is in the field of furnaces for molten material, for example glass, and relates more particularly to an electrode holder for holding an electrode end in a position exposed to the molten material.

[0004] The invention is described in the example of the production and management of molten glass. However, it is by no means limited to this and can be applied similarly to other molten materials.

[0005] More generally, the invention is described in this document with regard to the application of molten glass. The term molten glass is to be understood in a broad sense and should not be considered a limitation. The invention applies in particular to an electrode holder for holding the electrode tip in a bath of a molten phase of mineral material. This may include, in particular, glass-like compositions such as glass wool, but also other compositions including rock wool.

[0006] To manufacture glass products, such as flat or hollow glass, glass wool, or rock wool, raw materials, including minerals and recycled glass, or natural raw materials such as basalt and lime, are stored in silos, then weighed and mixed to form the glass composition. This glass composition is placed in a melting furnace, which can generate temperatures of up to 1550°C, where the glass composition melts. This is referred to as liquid glass or molten glass. The molten material is then conveyed, notably via a conditioning channel, to forming chambers where the molten glass is shaped before cooling and solidifying (for example, fiber forming, rolling, extrusion, blowing, etc.).The transfer of molten glass from the melting furnace to the forming stage is a key point in the manufacturing process that must be precisely controlled to ensure a homogeneous temperature and a suitable viscosity for the subsequent forming and intended applications. Between the melting furnace outlet and the extraction point for further processing, the liquid glass flows through a channel where it is kept in a liquid state for delivery to the processing lines. This channel extends locally along a longitudinal axis and comprises at least two opposing side walls, and an opposing bottom and top wall, each connecting the side walls. It is therefore understood that the two side walls are spaced apart, the bottom and top walls are spaced apart, and the liquid glass flows between these four walls.Typically, each side wall includes at least one window, either opposite or staggered, which provides an opening through the side wall. Consequently, each side wall of the channel may include a window, preferably a plurality of windows spaced apart along an axis parallel to the longitudinal axis. Each window in one side wall is either opposite a window in the other side wall or staggered with a window in the other side wall. It should be noted that the top or bottom wall of the channel may also include such a window.

[0007] However, the invention also applies in the case of a channel where a single wall is provided with one or more windows.

[0008] An electrode, usually made of molybdenum or tungsten, is positioned across each of these windows. The electrodes are electrically powered and their purpose is to dissipate energy through the Joule effect in the liquid glass within the channel, thus maintaining the glass in a liquid state until it reaches the extraction point. The arrangement of the electrodes (opposite or staggered) and their spacing depend on the available power.

[0009] Each electrode is at least partially immersed in the liquid glass and held in position by an electrode holder. Such an electrode extends within the liquid glass, for example, perpendicular to the wall it passes through. More generally, the electrode can extend along an axis intersecting the wall it passes through. Given the channel's operating conditions, several problems arise. First, the electrode is held in the liquid glass and is therefore exposed to high-temperature liquid glass. Despite the application of protective coatings or special surface treatments, the electrode can wear due to the intense heat conditions to which it is exposed. Furthermore, the electric current flowing through the electrode and the power density at which it operates can lead to increased electrode wear. As it wears, the electrode shortens.It is then necessary to change it, or to use a long electrode mounted on an electrode holder that an operator slides towards the channel to push the electrode into the liquid bath, thus maintaining a constant electrode length in the liquid glass. This is called a pushable electrode holder.

[0010] On the other hand, the electrode, electrode holder, and channel walls are exposed to high temperatures. To preserve their structural integrity, cooling is essential. Existing solutions offer water cooling within a cooling box in contact with the refractory material forming the outer wall of the channel. This type of solution is not optimal, as it requires numerous ancillary pieces of equipment that are expensive and bulky, and supplemental cooling air is often necessary. There are also systems that operate solely with air cooling. Such systems supply external air directly to the outer wall of the channel. In addition to being bulky, the cooling is not optimal. Furthermore, they are not compatible with push-in electrode holders.

[0011] The invention aims to overcome these drawbacks by providing a pushable, gas-cooled electrode holder, preferably air-cooled, with a compact shape. Thanks to a well-designed electrode holder, such a holder ensures optimized cooling of the holder, the electrode, and the channel wall, while allowing the electrode to slide freely in the liquid glass.

[0012] To this end, the invention proposes an electrode holder intended to hold an electrode extending along a principal axis through a window of a container, the electrode holder being characterized in that it comprises a casing extending along the principal axis and comprising a first hollow portion, a second hollow portion and a fixing interface separating the first and second hollow portions,

[0013] the first hollow portion being intended to house the electrode, one end of the electrode being intended to be fixed to the fixing interface,

[0014] the second hollow portion comprising an opening for the introduction of a gas, a cooling duct extending along the main axis, and at least one orifice passing through the casing,

[0015] and a thrusting mechanism configured to apply a thrusting force on the second hollow portion along an axis parallel to the main axis, so as to translate the envelope along the main axis.

[0016] Thanks to these features, the electrode holder incorporates both a mechanism for pushing the electrode into the container and a gas cooling device, all while maintaining a compact form. The novelty of the gas cooling principle of the invention lies in the fact that it is integrated within the electrode holder. A cooling channel is defined within the electrode holder's casing itself, through which gas circulates. The gas is in contact with the casing and the mounting interface. This contact allows for heat exchange between the casing, the electrode, and the gas. The casing transfers thermal energy to the gas as it passes through the second hollow section. The orifice defines a gas outlet along an axis perpendicular to the main axis.It is thus understood that the second hollow portion forms a gas cooling device which allows cooling of the back of the electrode (i.e., cooling of the attached end of the electrode) and of the electrically conductive sheath.

[0017] The casing is preferably made of a thermally conductive material, for example, metal. This allows for better heat exchange between the gas and the casing. For example, the thermally conductive material may have a thermal conductivity of at least 10 W / m·K at 25°C, for example, at least 30 W / m·K at 25°C, preferably at least 40 W / m·K at 25°C. The casing may also be made of an electrically conductive material, for example, metal. This allows the passage of an electric current to power the electrode. For example, the electrically conductive material may have an electrical conductivity of at least 1 x 10⁻¹² W / m·K. 6 S / m, for example at least 2xl0 6S / m (Siemens per meter). Preferably, the casing is made of a material chosen from steel, copper, aluminum, silver, or an alloy of these metals, more preferably from steel or one of its alloys. This allows for a combination of thermal conductivity, electrical conductivity, and mechanical strength.

[0018] According to an optional feature of the invention, the electrode holder further comprises a cooling box arranged coaxially around the casing so as to enclose the casing between a primary and a secondary section of the casing on either side of the mounting interface and defining an annular volume, with at least one through-hole opening into the annular volume. In particular, the cooling box may extend along the principal axis between a first end and a second end and may enclose the casing at each of its two ends, so as to form an annular volume between the two ends of the cooling box.

[0019] Advantageously, the first and second ends are equipped with sealing gaskets positioned at the ends of the annular volume. Such sealing gaskets can be made of any material that guarantees a watertight seal and has sufficient mechanical and thermal resistance under operating conditions, particularly withstanding temperatures up to 800°C. Non-limiting examples of possible materials for such gaskets include graphite, fiber (e.g., silica), or copper.

[0020] Once the electrode holder is positioned so that the electrode is immersed in the molten glass, contact is established between the cooling box and the vessel wall. In other words, the cooling box is pressed against the outer face of the vessel wall. This arrangement allows for the cooling of the outer face of the vessel wall. Furthermore, the annular volume defined by the cooling box around the shell acts as a collector for the gas exiting the orifice. This volume contributes to the cooling of both the shell and the vessel wall. The combined effect of gas circulation within the second hollow portion of the shell and gas circulation from the orifice into the annular volume provides a large contact surface between the gas and the surrounding walls, thus increasing heat exchange between the hot walls and the gas intended to receive thermal energy.

[0021] According to an optional feature of the invention, the cooling box comprises at least one side wall and at least one vent passing through at least one side wall. Preferably, the at least one vent is positioned on a portion adjacent to the first end of the cooling box, said first end being intended to be positioned against the outer face of the container wall.

[0022] The vent defines a gas outlet along an axis perpendicular to the main axis. It is thus understood that the cooling box forms a gas cooling device that cools the electrode tip in the electrode holder and the external face of the container wall. Coupled with the cooling duct, the cooling box optimizes the cooling of the electrode holder.

[0023] By ensuring the cooling of the external face of the container wall to a temperature of around 600°C, we also ensure that no condensate or molten glass (glass solidifying at 800°C) gets into the gap between the electrode holder casing and the window in the wall.

[0024] According to an optional feature of the invention, the electrode holder includes a device for positioning the sheath along the main axis. The positioning device may, for example, be located on the sheath, preferably on the second hollow portion of the sheath. It may, for example, include a visual element (e.g., a scale or markings) and / or a stop element. Preferably, the positioning device includes at least one stop element. In other words, it includes an element that limits the movement of the sheath along the main axis or serves as a stopping point during this movement.

[0025] Advantageously, the positioning device may include a stop wedge, for example, removably positioned on the casing, abutting the outer face of the container, either directly or indirectly by abutting the cooling box itself abutting said outer face. By offsetting the position of this stop wedge by a predefined distance, the casing is allowed to translate along the main axis until the stop wedge is abutted.

[0026] According to an optional feature of the invention, the electrode holder includes an electrical connection terminal attached to the casing. This electrical connection terminal supplies electrical power, which then passes through the casing to the electrode. In turn, the electrode generates the thermal power required by the molten glass in which it is immersed within the container.

[0027] As an optional feature, the second hollow portion may include a converging wall, for example concentric, to guide the gas towards the center of the fastening interface. By locally reducing the cross-section of the cooling duct, the gas flow is accelerated and concentrated towards a central part of the fastening interface, thus accelerating its cooling.

[0028] The invention also relates to an electrode assembly comprising an electrode extending along a principal axis and such an electrode holder, the electrode being housed in the first hollow portion of the electrode holder's casing.

[0029] The invention also covers a container for holding molten glass. By container, we mean any object capable of containing molten glass, for example, a channel, for example, for transporting or packaging molten glass as described in the introduction, or a furnace or melting chamber. According to the invention, the container is characterized in that it comprises:

[0030] at least one wall including a through window,

[0031] an electrode extending along a principal axis, an electrode holder as described previously,

[0032] the electrode being housed in the first hollow portion of the electrode holder's casing, the first hollow portion of the casing extending at least partially through the through window.

[0033] Molten glass also refers to any type of vitrifiable material, particularly for the manufacture of thermal and acoustic insulation products, including boron-containing glass for the manufacture of glass wool for thermal and acoustic insulation, or aluminosilicate-type compositions for the manufacture of rock wool for thermal and acoustic insulation.

[0034] The through-window (and therefore the electrode holder with its electrode) is located on a section of the wall intended to be in contact with the molten glass. Such a wall can be a side wall of the container, but it can also be a bottom or top wall, and / or an inclined wall.

[0035] According to an optional feature of the invention, the container further comprises a gas source, preferably air, fluidly connected to the gas inlet opening of the electrode holder. Alternatively, the gas may be an inert gas such as nitrogen.

[0036] The invention also covers a method for elongating an electrode through a through-window of such a container containing molten glass, said method comprising the following steps:

[0037] When a portion of the electrode placed in the molten glass is less than a predefined length, interrupt the introduction of the gas through the inlet opening.

[0038] Apply a thrust force to the second hollow portion using the thrust mechanism, so as to translate the electrode through the through-window,

[0039] Introduce gas through the inlet opening. Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples given with reference to the attached schematic drawings on the other hand, in which:

[0040] [Fig. 1] schematically represents a cross-sectional view of a channel at the level of a through window through which an electrode holder of the invention is disposed;

[0041] [Fig. 2] schematically represents a cross-sectional view of an electrode holder according to the invention equipped with an electrode in a first position and in a second position;

[0042] [Fig. 3] shows a cross-sectional view of an electrode holder according to the invention; [Fig. 4] shows a top view of an electrode holder according to the invention. The features, variations, and different embodiments of the invention, as described or as they will be presented in the detailed description that follows, can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variations of the invention may be conceived comprising only a selection of features described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0043] For the sake of clarity, the same elements are designated by the same references in the different figures.

[0044] Figure 1 schematically represents a cross-sectional view of a channel 100 at the level of a through-window 101 through which an electrode holder 10 of the invention is positioned. This illustration shows a channel designed to receive an electrode holder. The upper part 200 of the channel is commonly called the superstructure. It is composed of an insulating material 201 that surrounds the laboratory vault 202. The wall 203 constitutes the vault insulation. The lower part 210 of the channel is called the infrastructure. It comprises a tank 211 composed of two side walls 212, 102 (also called legs) and the base 213 forming the lower part of the tank. The liquid glass 250 is placed in the tank and thus flows through the channel. As illustrated in Figure 1, the side wall 102 includes a through-window 101.In what follows, the term "window" or "through window" refers to an opening that extends through a wall. In other words, a through window is a localized opening in a wall. This opening forms a channel through the wall, allowing the passage of an electrode. The through window is generally circular in cross-section and has a diameter approximately equal to that of the electrode intended to pass through it. However, the through window may have a different cross-section, particularly one complementary to that of the electrode. In Figure 1, the through window extends along an X-axis perpendicular to the wall 102. This is an illustrative example. The X-axis may also intersect the wall 102, and is not necessarily perpendicular to it.

[0045] Channel 100 is described here by way of illustration to present the framework of the invention. As explained in the introduction, molten glass flows through channel 100 between the outlet of the melting furnace and the extraction point for further processing. However, as will become clear from the following description, the invention applies to any container 100, whether it be a channel, a furnace, or a melting chamber. Similarly, the through-window 101, shown here through wall 102, can be a through-window through any other wall of the channel. In other words, a through-window 101 can be positioned through wall 102 and / or wall 212 and / or floor 213 and / or arch 202.

[0046] The electrode holder 10 supports an electrode 50 immersed in the liquid glass. The electrode holder 10 comprises a casing 11 connected to an electrical terminal 60 to supply power to the electrode 50, thereby providing thermal energy by Joule heating to maintain the glass in liquid form within the channel. The casing 11 also has an inlet 15 for a cooling fluid. For example, air is introduced into the inlet 15 to cool the casing 11. The technical details of the invention will be described below with reference to Figures 2 to 4.

[0047] Figure 2 schematically represents a cross-sectional view of an electrode holder 10 according to the invention, equipped with an electrode 50 in a first position (upper part of the figure) and in a second position (lower part of the figure). As explained previously, the electrode holder 10 of the invention is designed to hold the electrode 50 extending along a principal axis X through a window 101 of a container 100. The principal axis X is here horizontal, that is, perpendicular to the side wall 102 of the container 100. This is a non-limiting representation. The principal axis X may be vertical, in which case it is perpendicular to a floor or ceiling wall of the container 100. Alternatively, the principal axis X may intersect one of the walls of the container 100. The principal axis X defines the axis along which the electrode 50 extends.Since electrode 50 is intended to be held in position through window 101, it is understood that window 101 passes through the wall along this same principal axis X.

[0048] As illustrated in the upper part of Figure 2, the wall 102 of the container 100 is at least partially covered with a layer of thermally insulating material 110. The whole is contained in a metal box 111 forming the structure of the container 100.

[0049] According to the invention, the electrode holder 10 comprises a casing 11 extending along the principal axis X. The casing 11 includes a first hollow portion 12, a second hollow portion 13, and a mounting interface 14 separating the first 12 and second 13 hollow portions. The casing 11 has the shape of a hollow tube, for example, with a circular cross-section, containing the mounting interface 14. The casing 11 thus defines the first hollow portion 12 and the second hollow portion 13 on either side of the mounting interface 14. The mounting interface 14 physically and fluidly separates the two hollow portions 12 and 13. The casing 11 is made of a metallic material, for example, steel or any other material that is a good electrical conductor. The electrode holder 11 includes an electrical connection terminal 60 connected to the casing 11.The electrical connection terminal 60 supplies power to the electrode 50 through the electrically conductive casing 11. The electrode 50 is typically made of molybdenum or tungsten. Such an electrode 50 exhibits high-temperature resistance and corrosion resistance. The casing 11, in addition to holding the electrode 50 in position, acts as an electrical conductor. The electrically powered electrode 50 is used as a heating element. This results in energy dissipation by Joule heating in the liquid glass in which the electrode 50 is immersed, thus maintaining the glass in a liquid state. The casing 11 also acts as a thermal conductor, notably by cooling the attached end of the electrode via the gas cooling the casing walls.

[0050] The first hollow portion 12 houses the electrode 50. The electrode 50 is thus partially inserted into the first hollow portion 12. One end 51 of the electrode 50 is fixed to the fixing interface 14. The assembly of the end 51 of the electrode 50 to the fixing interface 14 can be achieved by means of a threaded interface or by any male-female connection. Thus, the electrode 50 is held in position within the housing 11. In addition, the fixing interface 14 allows the passage of electrical power to the electrode 50.

[0051] As schematically represented in Figure 2, three electrode zones can be defined: a first electrode zone 50 corresponds to the portion of the electrode extending from the fixing interface 14 into the first hollow portion 12; a second electrode zone 50 corresponds to the portion of the electrode that is positioned through the wall 102, in the through-window 101; a third electrode zone 50 corresponds to the portion of the electrode in contact with the liquid glass. The third electrode zone is the portion of the electrode that protrudes from the wall.

[0052] The casing 11 also defines the second hollow portion 13. The second hollow portion 13 extends within the casing 11 from the mounting interface 14 but in a different direction than the first hollow portion 12. While the first hollow portion 12 is oriented towards the inside of the container 100 when the electrode holder is in the position of retaining the electrode 50 in the container 100, the second hollow portion 13 extends outwards from the container 100. The second hollow portion 13 includes a gas inlet 15 and a cooling conduit 16 extending along the principal axis X. In addition, the second hollow portion 13 includes at least one orifice 17 passing through the casing 11. The opening 15 is shown on a lateral part of the casing 11, that is, so as to introduce the gas perpendicularly to the principal axis X.However, we do not depart from the scope of the invention with an opening 15 which would be positioned at the end of the second hollow portion 13, so as to introduce the gas parallel to the main axis X, or to any other orientation of the gas flow entering the second hollow portion 13.

[0053] The orifice 17 is a through-opening in the casing 11 that provides fluidic communication between the second hollow section 13 and the exterior of the casing 11. Gas, for example air or nitrogen, is introduced through the opening 15 into the second hollow section 13. This gas circulates within the second hollow section 13. The cooling conduit 16 is defined within the second hollow section 13 between the gas introduction opening 15 and the fastening interface 14. It is understood that the cooling conduit 16 is formed by a portion of the second hollow section 13. The gas introduced through the opening 15 thus circulates within the cooling conduit 16 from the opening 15. As it circulates within the second hollow section 13 of the casing 11, heat exchange occurs between the hot walls of the casing 11 and the fastening interface 14 and the gas in contact with these hot walls. The gas contributes to the cooling of envelope 11.Similarly, with the electrode 50 fixed to the mounting interface 14, the mounting interface 14 constitutes a hot spot on the casing 11. The gas circulating in the second hollow portion 13 helps to dissipate this thermal energy. The gas introduced through the opening 15 and having circulated in the cooling duct 16 has absorbed some of the thermal energy from the casing 11. It leaves the second hollow portion 13 through the orifice 17. In the cross-sectional view of Figure 2, two orifices 17 can be seen on either side of the main axis X. However, the electrode holder of the invention may comprise a single orifice 17, or a plurality of orifices 17 passing through the casing 11 from the second hollow portion 13, uniformly distributed, or not, over the peripheral surface of the casing 11.

[0054] The orifice(s) 17 are advantageously positioned closer to the fastening interface 14 than to the gas inlet opening 15. This arrangement of the orifices 17 ensures a long cooling channel 16 conducive to heat exchange between the casing 11 and the gas circulating in the cooling channel. This results in improved cooling of the casing 11 and the fastening interface 14.

[0055] The second hollow section 13 forms a cooling device for the casing 11 and the fastening interface 14. Thanks to the gas circulation within the second hollow section 13, the cooling of the fastening interface 14 and the casing 11 is ensured. The orifice(s) 17 define an outlet for the heated gas that has circulated in the second hollow section 13. The orifice(s) 17 thus define a gas outlet along an axis perpendicular to the main axis X.

[0056] The gas introduced through opening 15 into the electrode holder 10 flows through the second hollow section 13 along streamlines essentially parallel to the principal axis X. This gas circulation is beneficial to the heat exchange between the walls of the casing 11 and the gas, increasing its thermal energy. This gas exits the second hollow section 13 radially through the orifice(s) 17. The airflow leaving the casing 11 at the orifice(s) 17 can also serve as a cooling gas for the outer wall of the container. Indeed, this wall is also very hot. By coming into contact with the outer surface of this outer wall, the gas that has flowed through the second hollow section 13 can also contribute to cooling the wall 102 of the container 100.

[0057] Other features of the invention related to cooling, particularly the cooling box 30, will be detailed based on Figures 3 and 4. Furthermore, the electrode holder 10 includes a thrust mechanism 18 configured to apply a thrust force to the second hollow portion 13 along an axis parallel to the main axis X, so as to translate the casing 11 along the main axis. In the upper part of Figure 2, the electrode holder 10 is in a first position. The electrode 50 is held in position along the main axis X. After a certain period of use, the electrode 50 wears down and its length in the liquid glass decreases. It is then necessary to move it so that a sufficient length of electrode 50 is immersed in the liquid glass of the container 100. By activating the thrust mechanism 18, a force is exerted on the second hollow portion 13.This results in the translation of the casing 11 towards the interior of the container 100. The second hollow portion 13, the fixing interface 14, and the first hollow portion 12, which are joined together, are translated as a single unit. Despite its wear, a sufficient length of the electrode 50, defined above as the third zone of the electrode, is positioned in the liquid bath contained in the container 100. This configuration corresponds to the positioning of the electrode holder shown in the lower part of Figure 2.

[0058] Figure 3 shows a cross-sectional view of an electrode holder 10 according to the invention. The electrode holder 10 shown in Figure 3 comprises the same elements as the electrode holder described previously in Figure 2. Other technical features will now be described.

[0059] In addition to the elements already shown in Figure 2, the electrode holder 10 illustrated in Figure 3 further comprises a cooling box 30 arranged coaxially around the casing 11 so as to enclose the casing 11 between a primary section S1 and a secondary section S2 of the casing 11 on either side of the mounting interface 14. The cooling box comprises a first end 35 and a second end 36. The first end 35 lies in the same plane as the primary section S1, and the second end 36 lies in the same plane as the secondary section S2. The cooling box 30 defines an internal housing that surrounds the portion of the casing 11 located between the primary section S1 and the secondary section S2.In other words, each end of the cooling box 30 includes an opening, a first opening being intended for the passage of the envelope 11 at the level of section S1 and a second opening being intended for the passage of the envelope 11 at the level of section S2. The envelope 11 is slid inside the cooling box by translation through the two openings.

[0060] The cooling box 30 defines an annular volume 31 outside the casing 11. It is thus understood that the cooling box defines two zones: the internal housing for the passage of the casing 11 and the annular volume 31 which surrounds the casing 11. The through orifice(s) 17 open into the annular volume 31.

[0061] The first end 35 of the cooling box 30 is abutted against the outer surface of the wall 102.

[0062] Thanks to these features, the cooling box 30 collects in its annular volume 31 the gas that has circulated in the cooling duct 16 of the casing 11 and exited through the orifice 17 passing through the casing 11. Being in contact with the wall 102 of the container 100, the cooling box 30 allows cooling of the outer face of the wall 102 of the container. The first and second ends 35, 36 can be fitted with heat-resistant seals 37, for example, made of graphite. These seals encircle the casing 11 at the ends 35, 36 of the cooling box. Their purpose is to keep the gas inside the annular volume 31 and to maintain the seal of the cooling circuit, particularly when the casing 11 slides inside the cooling box during the activation of the thrust mechanism 18.

[0063] Due to the length of the cooling box (along the principal axis X), when the thrust mechanism 18 is activated, the envelope 11 is translated inside the cooling box 30, i.e. the electrode 50 is translated towards the inside of the container, the fixing interface 14 is also translated in this direction but remains positioned inside the cooling box 30. Regardless of the translational state of the electrode holder 10, the orifice(s) 17 open into the annular volume 31.

[0064] The cooling box 30 includes at least one side wall 32. The side wall 32 is the wall that connects the ends 35 and 36. It is the external wall of the cooling box 30. Advantageously, the cooling box 30 includes at least one vent 33 passing through at least one side wall 32. The vent 33 is an opening passing through the side wall 32 of the cooling box. The vent 33 establishes fluidic communication between the annular volume 31 and the exterior of the cooling box 30. Thus, the gas collected in the annular volume 31 can leave the cooling box through the vent(s) 33. In Figure 3, two vents 33 are shown located on either side of the main axis X.However, the side wall 32 of the cooling box 33 may include a single vent 33, or a plurality of vents 33 passing through the side wall 32 from the annular volume 31, uniformly distributed, or not, over the surface of the side wall 32 of the cooling box 30.

[0065] The vent(s) 33 are advantageously positioned closer to the first end 35 than to the second end 36 of the cooling box, preferably on a portion adjacent to the first end 35 of the cooling box. This arrangement of the vents 33 allows the gas to maximize heat exchange, notably by directing the gas towards the hottest point of the annular volume 31 (i.e., towards the wall 102 of the container 100). In other words, the residence time of the gas in the annular volume 31 is long enough to allow heat exchange between the casing 11 and the gas. The contact between the end 35 of the cooling box 30 and the outer surface of the wall 102 of the container 100 allows the gas to absorb heat from the wall 102. This results in improved cooling of the casing 11 and the outer face of the wall 102 of the container 100.

[0066] Each vent 33 defines a gas outlet along an axis perpendicular to the main axis X, allowing cooling of the outer wall 102 of the container 100. The gas exits the cooling box 30 in a radial direction. The gas can thus come into contact with the wall 102 and the insulation layer 110. This contact allows for further heat exchange between the hot zones and the gas.

[0067] Thanks to this feature, the cooling process lowers the temperature of wall 102 to around 600°C. Since glass solidifies at 800°C, the cooling provided by the cooling box 30, which is in contact with wall 102 and delivers a flow of gas directed along this wall, ensures that molten glass and condensate do not pass between the casing 11 and the through window 101.

[0068] According to this optional feature, the invention proposes the cooling box 30 arranged around the envelope 11, so that the envelope 11 can slide inside the cooling box 30.

[0069] The gas, for example air, is introduced through the opening 15 of the second hollow section 13 of the casing 11. This gas flows through the second hollow section 13, which then defines the cooling duct 16. In this process, the casing is cooled by heat exchange between the gas and the walls of the cooling duct 16. Before leaving the second hollow section 13, the gas passes over the mounting interface 14 on the side of the second hollow section 13, thus contributing to the cooling of this surface. Note that the heat exchange surface at the mounting interface 14 can be increased to improve cooling. The gas exits the second hollow section 13 radially through the orifice 17 and is collected in the annular volume 31 of the cooling box 30. The gas continues its path within the cooling box 30.In other words, the gas flows towards the first end 35 of the cooling box. During its passage through the cooling box 30, the gas undergoes further heat exchange with the casing 11 along the first hollow section 12. Upon exiting the cooling box 30 radially through the vent 33, the gas comes into contact with the outer surface of the wall 102 of the container 100, thus contributing to the cooling of this surface. The invention is based on a judicious and optimized circulation of a gas flow through the electrode holder 10. The gas is introduced into the second hollow section 13 of the casing 11 and circulates inside the casing 11 along its second hollow section 13, then outside the casing 11, for example along its first hollow section 12, i.e., inside the electrode holder 10. It provides initial cooling of the casing 11 and the mounting interface 14.Next, the gas exits the second hollow portion 13 in a radial direction. Depending on the variant of the electrode holder 10, two configurations are possible. Either the electrode holder does not have a cooling box 30, in which case the gas exiting the second hollow portion 13 is directed towards an external face of the wall 102 of the container where the through-window 101 is located. The gas thus cools the wall 102 of the container. Or the electrode holder is equipped with a cooling box 30, in which case the gas exiting the second hollow portion 13 is directed towards the annular volume 31 of the cooling box 30. The gas cools the casing 11, the mounting interface 14, and the external surface of the wall 102 against which the cooling box 30 abuts. In addition, the gas exits the cooling box 30 radially through the vent 33.By proceeding in this manner, the gas flow leaving the cooling box 30 is directed towards an external face of the wall 102, thereby cooling said wall. This results in effective cooling of the wall around the electrode 50.

[0070] According to an optional feature of the invention, the electrode holder 10 includes a thermocouple holder 70 disposed on the side wall 32 of the cooling box 30. The thermocouple holder 70 allows for the temporary insertion of a thermocouple to measure the temperature of the outer surface of the wall 102. Thanks to the thermocouple holder 70, the thermocouple does not necessarily have to be permanently left in the electrode holder. It can be inserted into the thermocouple holder 70 only when its use is required. This feature allows for the sharing of thermocouples. It is no longer necessary to provide a thermocouple for each window 101, but the same thermocouple can be used to determine the temperature at several locations successively.

[0071] Figure 4 shows a top view of the electrode holder 10 according to the invention shown in Figure 3. In this view, the pushing mechanism 18 comprises two tie rods 181, 182 and a central plate 183. The central plate 183 is connected to the two tie rods 181, 182. By means of a screw system, the central plate 183 can be pushed, by translation along the tie rods 181, 182, against the casing 11 so as to translate it along the principal axis X, in the direction of the container 100, in order to increase the protruding area of ​​the electrode 50 inside the container 100 (and thus increase its contact surface with the glass bath).

[0072] According to an optional feature of the invention, the electrode holder 10 includes a positioning device 40 for the casing 11, in particular for the second hollow portion 13, along the principal axis X. The positioning device 40 may, for example, be a stop wedge fixed, by means of screws for example, to the second hollow portion 13, on the external surface of the casing 11, and abutting, directly or indirectly, against the external surface of the wall 102 of the container 100. The stop wedge may include several bore-type perforations, spaced at a predefined distance dl, for example 25 mm (millimeters). One or two screws allow the stop wedge to be fixed in position. In one embodiment, the perforations are circular. In another embodiment, the perforations are oblong to allow finer adjustment of the positioning of the casing 11.

[0073] In a first variant of the electrode holder 10 without a cooling box, the stop wedge is against the outer face of the wall 102. In a second variant of the electrode holder 10 with the cooling box 30, the stop wedge is against the second end 36 of the cooling box 30, the cooling box 30 itself being against the outer face of the wall 102.

[0074] When electrode 50 is partially worn, that is, when the portion of electrode 50 immersed in the liquid glass has eroded, the thrust mechanism 18 must be activated to translate the casing 11, and therefore electrode 50, along the principal axis X towards the interior of the container 100. Advantageously, this translation should be controlled to push it a predefined distance, for example, 25 mm (millimeters). The positioning device 40 allows for such control. By removing the screw from a perforation, it is possible to shift the stop wedge by the distance dl. To do this, the stop wedge is shifted and then secured by means of the screw inserted in the adjacent perforation. In other words, the stop wedge is translated by a distance dl along the principal axis X away from the outer face of the wall 102. The thrust mechanism 18 can then exert a force through the central plate 183 on the second hollow portion 13.This results in the envelope 11 moving inwards towards the container 100. Once the envelope 11 has traveled a distance dl, the stop wedge will again be against the outer face of the wall 102 (or against the cooling box 30, if applicable). The positioning device 40 thus allows the envelope 11, and therefore the electrode 50, to move a predetermined distance until the electrode holder is again against the outer face of the wall 102, either directly or indirectly.

[0075] The invention also relates to an electrode assembly comprising an electrode 50 extending along a principal axis X and an electrode holder 10 as described above. The electrode 50 is housed in the first hollow portion 12 of the casing 11 of the electrode holder 10. This assembly is intended to be positioned through a through-window 101 in a wall 102 of a container 100 containing molten glass.

[0076] The invention also relates to a container 100 for holding molten glass. Such a container 100 comprises at least one wall 102 including a through-window 101. The wall 102, as illustrated in the figures, is a side wall of the container 100. However, the invention is not limited to this. The wall may be a bottom wall, a floor wall, an inclined wall, or even a wall with a radius of curvature. It is understood from the above that the through-window 101 is located on a portion of the wall that is in contact with the molten glass. Thus, the electrode 50 is immersed in the molten glass in order to maintain it at the temperature required to keep it in this phase.

[0077] The container 100 includes an electrode 50 extending along a principal axis X, and an electrode holder 10 as described previously. In such a container 100, the electrode 50 is inserted into the first hollow portion 12 of the shell 11 of the electrode holder 10. The electrode holder 10 is partially disposed through the through-window 101. More precisely, the first hollow portion 12 of the shell 11 extends at least partially through the through-window 101.

[0078] Container 100 can be a channel as explained above.

[0079] However, the invention applies to any container suitable for holding a molten material such as molten glass. In other words, the container 100 can be a furnace or a melting chamber.

[0080] According to an optional feature of the invention, the container 100 further comprises a gas source 103, preferably air, fluidly connected to the gas inlet opening 15 of the electrode holder. The gas source 103 supplies cooling gas to the electrode holder 10. The gas is advantageously air, but may be another inert gas, for example, nitrogen. Optionally, the gas source is a cooled gas source. This improves the cooling.

[0081] As illustrated in the figures, the invention is based on a gas-cooled, pushable electrode holder. The specific arrangement of gas circulation circuits within the electrode holder provides compact, optimized cooling of the electrode holder, the electrode, and the container wall, while allowing the electrode to slide freely in the liquid glass.

[0082] The invention allows gas to circulate in specific areas, particularly at the electrode attachment interface and the outer face of the container wall, to control the temperature at these points. A thermocouple enables temperature measurement at various locations. Based on these measurements, the electrode holder of the invention allows for precise control of the gas injection into the holder according to the required cooling. If temperatures exceeding predefined threshold temperatures are measured, the gas flow rate introduced at the opening of the second hollow section can be increased to meet the need for enhanced cooling.

[0083] The invention also relates to a method for elongating an electrode 50 through a through-window 101 of a container 100 as described above. The container 100 includes a gas source for cooling the electrode holder and the hot walls. The container 100 contains molten glass. According to the invention, the electrode elongation method comprises the following steps:

[0084] When a portion of the electrode 50 disposed in the molten glass is less than a predefined length, interrupt the introduction of the gas through the introduction opening 15,

[0085] Apply a thrust force to the second hollow portion 13 by the thrust mechanism 18, so as to translate the electrode 50 through the through window 101,

[0086] Introduce gas through the inlet opening 15.

[0087] Generally, a visual check is used to identify when the portion of the electrode in the molten glass is less than the predefined length. During operation, gas from the gas source is introduced into the electrode holder through the gas inlet opening 15. The gas then flows through the cooling channel 16, as explained above.

[0088] The advantage of the electrode holder of the invention is that it allows for efficient cooling integrated within the holder itself. The walls of the casing and the walls at the through-window are cooled. Thus, any molten glass that might enter between the casing and the wall is cooled and solidifies in the gap between the casing and the wall. This results in a glass plug. In other words, this solidified glass plug prevents any further infiltration of molten glass into this gap. This plug is therefore advantageous during normal operation of the electrode and its holder. However, due to electrode wear, it is necessary to move it towards the molten glass bath to lengthen the portion of the electrode immersed in the molten glass within the container. Therefore, the thrust mechanism 18 must be activated.

[0089] However, since a glass plug has formed beforehand, it must first be removed before any movement of the electrode. For this reason, the cooling process must first be stopped by shutting off the gas supply to the cooling duct 16. Once the cooling is stopped, the walls heat up. The plug, being exposed to a higher temperature, returns to a liquid state. It is then possible to push the electrode 50 towards the molten glass bath. To do this, the pushing mechanism 18 is activated. The central plate 183 is translated along the tie rods 181, 182. During its translation, it applies a pushing force against the second hollow portion 13 of the shell, resulting in the translation of the shell 11 and therefore of the electrode 50 towards the center of the container.When the electrode is immersed in the molten glass for a sufficient length, which can be achieved, for example, by means of the positioning device 40 of the casing 11, the cooling of the electrode holder can be reactivated. The gas from the gas source 103 can again be introduced through the inlet opening 15. Since the cooling is operational again, if liquid glass enters the space between the casing and the wall, this portion of liquid glass is cooled, solidifies, and forms a plug preventing any further infiltration of liquid glass.

[0090] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the features of different embodiments of the invention can be combined to carry out the invention, provided that these embodiments are not incompatible with each other.

Claims

DEMANDS 1- Electrode holder (10) intended to hold an electrode (50) extending along a principal axis (X) through a window (101) of a container (100), the electrode holder (10) being characterized in that it comprises a casing (11) having the shape of a hollow tube extending along the principal axis (X) and comprising a fixing interface (14) within it, a first hollow portion (12), a second hollow portion (13), the fixing interface (14) physically and fluidly separating the first (12) and the second (13) hollow portions, the first hollow portion (12) being intended to house the electrode (50), one end (51) of the electrode (50) being intended to be fixed to the fixing interface (14), the second hollow portion (13) comprising an opening (15) for the introduction of a gas, a cooling duct (16) extending along the main axis (X), and at least one orifice (17) passing through the casing (11), and a thrusting mechanism (18) configured to apply a thrusting force on the second hollow portion (13) along an axis parallel to the main axis (X), so as to translate the envelope (11) along the main axis. 2- Electrode holder (10) according to claim 1, further comprising a cooling box (30) arranged coaxially around the envelope (11) so as to enclose the envelope (11) between a primary section (S1) and a secondary section (S2) of the envelope (11) on either side of the fixing interface (14) and defining an annular volume (31), the at least one through orifice (17) opening into the annular volume (31). 3- Electrode holder (10) according to claim 2, in which the cooling box (30) comprises at least one side wall (32) and comprises at least one vent (33) passing through at least one side wall (32). 4- Electrode holder (10) according to any one of claims 1 to 3, comprising a positioning device (40) for the casing (11) along the main axis (X). 5- Electrode holder (10) according to any one of claims 1 to 4, comprising an electrical connection terminal (60) connected to the casing (11). 6- Electrode assembly comprising an electrode (50) extending along a principal axis (X) and an electrode holder (10) according to any one of claims 1 to 5, the electrode (50) being housed in the first hollow portion (12) of the housing (11) of the electrode holder (10). 7- Container (100) intended to contain molten glass, characterized in that it comprises: at least one wall (102) comprising a through window (101), an electrode (50) extending along a principal axis (X), an electrode holder (10) according to any one of claims 1 to 5, the electrode (50) being housed in the first hollow portion (12) of the envelope (11) of the electrode holder (10), the first hollow portion (12) of the envelope (11) extending at least partially through the through window (101). 8- Container (100) according to claim 7, further comprising a gas source (103), preferably air, fluidly connected to the gas introduction opening (15) of the electrode holder. 9- Method for elongating an electrode (50) through a through window (101) of a container (100) according to claim 8 containing molten glass, said method comprising the following steps: When a portion of the electrode (50) disposed in the molten glass is less than a predefined length, interrupt the introduction of the gas through the inlet opening (15), Apply a thrust force on the second hollow portion (13) by the thrust mechanism (18), so as to translate the electrode (50) through the through window (101), Introduce gas through the inlet opening (15).

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