Glass furnace monitored by electroreflectometry

Abstract

The invention relates to a glass furnace comprising: a device for monitoring the state of components of the furnace (30) by time-domain or frequency-domain electroreflectometry, the device comprising an array of linear electromagnetic waveguides (12) extending parallel to the hot surface (37) and at a suitable distance such that, in use, the waveguides are at a temperature higher than 500 DEG C and lower than 1300 DEG C; and comprising a plurality of discontinuities, referred to as "basic discontinuities" (24):-randomly distributed at least along the measurement means of the waveguide, and-capable of generating echoes, referred to as "secondary basic echoes", having an amplitude greater than 0.5%, preferably greater than 1% and less than 30%, of the amplitude of the back lobe echoes reflected by the output end of the waveguide; or consists of: a relief or a relief resulting from non-uniform segmentation of a dielectric material located between the first and second electrical conductors, or a local change in the distance between the first and second electrical conductors, or a local change in the distance between the first and / or second electrical conductors on the one hand and the dielectric material of the support on the other hand, or a change in the structure and / or composition of the environment around or between the first and second electrical conductors. The number of basic discontinuities per meter of the measurement component of the waveguide is greater than 10. The discontinuous point may be a bead (23).

Description

TECHNICAL FIELD

[0001] The present invention relates to a glassmaking furnace equipped with a device for monitoring the state of a component of such a furnace, in particular the state of the refractory lining of the chamber of the furnace.

[0002] The present invention also relates to a method for manufacturing such a furnace and a method for monitoring the state of the refractory lining of such a furnace. BACKGROUND

[0003] Many glass products are made by melting and refining a glassifiable raw material mixture, these raw materials comprising compounds such as oxides, carbonates, sulfates and nitrates. These two steps are carried out in a furnace, the main constituent elements of which are refractory products capable of withstanding the thermal and mechanical stresses, in particular high temperatures, encountered in these furnaces. Thus, a glassmaking furnace generally comprises a large amount of refractory products and is arranged in different places according to the properties of the refractory products. For each component of the furnace, the chosen product does not lead to a defect that would make the glass unusable (as this would reduce the yield) and will have sufficient resistance over a long period of time to provide a satisfactory service life to the furnace.

[0004] Figure 1 A half cross section of a glassmaking furnace 10 is shown schematically. In particular, the hearth 11, the metal structure 13 and the superstructure 16 are shown. The hearth 11 for containing the molten glass comprises vertical side walls 22 and a bottom 41. The side walls 22 are generally constituted by side hearth bricks which extend to an upper edge 29 over the entire height of the hearth.

[0005] The superstructure 16 generally comprises an intermediate layer 17 at its base on which it rests on the metal structure, side walls 26 which rest on the intermediate layer 17 and a top 28 which is also formed of refractory bricks.

[0006] A heating system (not shown) comprising, for example, burners is generally arranged in the side walls 26. The metal structure 13 is generally made of cast iron which encircles the side walls 22 of the hearth on the outside. It bears the weight of the superstructure 16.

[0007] The hearth 11 and the superstructure 16 are the components of the furnace which define the chamber in which the glass is melted. They define a hot face 37 which is in contact with the molten glass or its gaseous environment.

[0008] As each component of the furnace has a hot face, the hot face is generally denoted by the term "object".

[0009] The hearth 11 and the superstructure 16 generally comprise a plurality of layers, i.e.

[0010] - a first dense brick refractory layer, preferably having a porosity of less than 10%, preferably less than 5%, which defines the hot face in contact with the glass or its gaseous environment;

[0011] - a second layer or "back layer" made of a material different from that of the first layer and which is more porous.

[0012] The back layer can comprise a first refractory sub-layer, called "barrier layer", intended to stop the penetration of the glass or to condense the glass vapours and / or a second refractory sub-layer or "insulation layer", which preferably comprises a porous refractory material to achieve a suitable heat distribution in use.

[0013] The barrier layer is preferably a layer of unshaped refractory product, in particular concrete or ramming mix. Generally, more than 90% of the number of particles of the barrier layer have a size (maximum dimension) of less than or equal to 5 mm to obtain a satisfactory surface finish and chemical composition such that the weight content of AI2O3 is at least 40%. The chemical composition of the barrier layer can be adapted according to the type of glass to enable it to withstand the molten glass sufficiently.

[0014] The insulation layer generally consists of unshaped silica-alumina insulating refractory material and / or refractory bricks or blocks. The insulating refractory material has a thermal conductivity measured at 1000°C of less than 7 W / m.K, preferably less than 5 W / m.K and preferably less than or equal to 3 W / m.K. Preferably, the porosity of the insulating refractory material is greater than 15%, preferably greater than 20% and more preferably greater than 30%. The porosity and thickness of the insulation layer are configured according to the required heat distribution.

[0015] Conventionally, the dense bricks of the first layer are made of a material resistant to contact with a glass having a temperature higher than 600°C, or even higher than 1000°C, or indeed higher than 1200°C. More than 90% of the weight of the dense bricks can consist of one or more oxides chosen from the group consisting of Zr02, AI2O3, Si02, Cr203, Y203and Ce02. The dense bricks preferably comprise more than 90% of Zr02, AI2O3and Si02.

[0016] In use, the chamber of the furnace is subjected to extreme conditions, in particular to a corrosive and abrasive environment, which can lead to gradual wear. In particular in the area in contact with the molten glass, the state of wear cannot be evaluated intuitively. In order to measure the residual thickness of the refractory bricks, i.e. the distance between the hot face of the refractory bricks and their cold face, i.e. the face opposite the hot face, a probe is therefore generally used at the gas-melt interface. The drawback of this method is the need to partially disassemble then reassemble the furnace and to provide only a point measurement.

[0017] Recently, WO2015147827 mentioned a device that emits waves, specifically radar waves, through bricks. Where possible, the reflected waves are analyzed. In practice, this process takes a very long time and does not allow for real-time monitoring.

[0018] WO2020025493 discloses an optical waveguide comprising a Bragg grating for measuring the remaining thickness at the bottom of a glass-making furnace. The inventors have tested the use of optical fibers and unexpectedly observed the appearance of crystallization, which is detrimental to the accuracy of the measurement and the mechanical strength of the optical fiber.

[0019] An apparatus for measuring the remaining thickness of a blast furnace lining is also known from JPH11264706A or JP3395886B2. This apparatus is highly invasive, increasing the risk of molten glass contamination, particularly the risk of the first layer cracking.

[0020] Therefore, a robust solution is needed that is easy to implement and allows for continuous and real-time assessment of the chamber condition of a glass-making furnace at any point, with good spatial resolution, without compromising the chamber lining or increasing the risk of contamination of the molten glass bath.

[0021] One object of the present invention is to at least partially satisfy this need. Summary of the Invention

[0022] According to the present invention, this objective is achieved by a glass manufacturing furnace comprising:

[0023] - A glass melting chamber having a hot surface exposed to the interior of the chamber;

[0024] - A device for monitoring the state of a component (preferably a component of the chamber) of the furnace by means of an electrical time-domain or frequency-domain reflectometry method, the component being referred to as an "object", the device comprising:

[0025] - An array of at least one filamentary waveguide, preferably an array of multiple filamentary electromagnetic waveguides, each waveguide comprising first and second (preferably metallic) electrical conductors electrically isolated from each other (preferably by means of a dielectric material) between its input and output ends.

[0026] The waveguide's measurement component includes multiple impedance discontinuities and extends parallel to the hot surface at a depth greater than 10 cm, preferably greater than 15 cm, greater than 20 cm, and preferably less than 200 cm, preferably less than 100 cm (the distance behind the hot surface relative to the interior of the chamber).

[0027] - An interrogator, electrically connected to the input, and configured to inject an interrogation signal through the input, receive a response signal reflected by the waveguide in response to the injection, analyze the response signal, and send a message about the state of the object based on the analysis.

[0028] The inventors have discovered that this arrangement of waveguides relative to the object provides an excellent trade-off between limited attenuation of the response signal and high robustness. Furthermore, the waveguide array makes it possible to monitor objects of any size, particularly the bottom of a furnace.

[0029] The object preferably includes an assembly of refractory bricks that defines the hot surface of the side wall, top, or bottom of the furnace, and preferably defines the hot surface of the bottom and / or top.

[0030] According to the first primary implementation, the impedance discontinuity includes a "basic discontinuity":

[0031] - It is capable, particularly when the length of the measuring component is less than 10 meters, of generating echoes with an amplitude greater than 0.5%, preferably greater than 1%, and preferably less than 30% of the amplitude of the terminal echo reflected from the output end of the waveguide in response to the injection of an interrogation signal. These echoes are referred to as "fundamental secondary echoes," and / or

[0032] It is formed by the following:

[0033] - A raised surface created by texturing the outer surface of the waveguide, and / or the dielectric material interposed between the first and second electrical conductors, and / or at least one of the first and second electrical conductors, and / or

[0034] - The irregular segmentation of the dielectric material creates raised areas, preferably, the pad made of the dielectric material has a length of less than 10 cm, more preferably less than 5 cm, more preferably less than 3 cm, more preferably less than 2 cm, and / or greater than 0.5 cm, and / or

[0035] - Local variations in the distance between the first and second electrical conductors; and / or

[0036] - The variation in the distance between the first and / or second electrical conductors and the dielectric material of the carrier, preferably made of a ceramic matrix composite material, on the one hand, and / or on the other hand.

[0037] - Changes in the structure and / or composition of the environment surrounding or between the first and second electrical conductors, preferably changes in the structure and / or composition of the dielectric material of the carrier, preferably made of a ceramic matrix composite material, preferably achieved by randomly dispersing particles and / or fibers of the dielectric material within the carrier, particularly within the matrix of the ceramic matrix composite material, or between the first and second electrical conductors.

[0038] It is worth noting that the inventors have discovered that the analysis of the fundamental secondary echo using electrical time domain reflectometry (TDR) or frequency domain reflectometry (FDR) allows for real-time, continuous, accurate, and reliable monitoring of the state of an object over long periods of time.

[0039] The fundamental discontinuity can generate a fundamental secondary echo in response to the injection of an interrogation signal (i.e., during use) to monitor the state of the object. For this monitoring purpose, the amplitude of the echo is preferably measured under conditions similar to or the same as those experienced by the measuring component when in use, preferably at temperatures above 500°C, preferably above 600°C, preferably above 700°C, preferably above 800°C, and / or below 1300°C, preferably below 1200°C, more preferably below 1100°C.

[0040] Preferably, the foundation discontinuities are randomly distributed at least along the measurement components of the waveguide, or even randomly distributed along the entire length of the waveguide. Advantageously, the random distribution avoids interference-related resonance effects.

[0041] Preferably, the basic discontinuity point is:

[0042] - A raised surface created by texturing the outer surface of the waveguide, and / or the dielectric material interposed between the first and second electrical conductors, and / or at least one of the first and second electrical conductors, for example by texturing through abrasion and / or chemical etching, and / or

[0043] - The irregular segments of the dielectric material are preferably raised by pads made of the dielectric material (e.g., preferably in the form of pad beads or cylinders with circular bases), the length of which is preferably less than 10 cm, preferably less than 5 cm, preferably less than 3 cm, more preferably less than 2 cm, and / or greater than 0.5 cm, and / or

[0044] - Local variation in the distance between the first and second electrical conductors.

[0045] The conductor can be sandwiched between two fabrics made of ceramic matrix composite material, or fixed to the surface of the ceramic matrix composite fabric, and the dielectric material (e.g., in the form of regular repeating units) preferably extends on the surface of one or more of the fabrics. The dielectric material can be formed, for example, by depositing a slurry and subsequently curing it.

[0046] In one embodiment, the interlayer has a thickness greater than 5 mm, greater than 8 mm, greater than 10 mm, and / or less than 50 mm.

[0047] In one embodiment, the fabric, preferably each of the above-mentioned fabrics, has a thickness greater than 0.5 mm, greater than 1 mm, and / or less than 10 mm, less than 5 mm, or less than 2 mm.

[0048] Preferably, more than 80% of the underlying secondary echo is generated by the underlying discontinuities generated through texturing.

[0049] One or more pads are preferably arranged at a distance of less than 1 mm from the first electrical conductor and / or the second electrical conductor, and preferably in contact with the first electrical conductor and / or the second electrical conductor.

[0050] Preferably, in the measuring component, one or more pads are disposed on the first electrical conductor and / or the second electrical conductor.

[0051] In one embodiment, in the measurement component, pads in the form of beads and made of dielectric material are passed through a first electrical conductor and / or a second electrical conductor, and multiple pads are arranged together to form a segmented protective coating extending over the entire length of the measurement component of the waveguide.

[0052] One or more pads are preferably spacers made of dielectric material, which are arranged to keep the first electrical conductor away from the second electrical conductor.

[0053] In one embodiment, one or more pads are movable relative to a first electrical conductor and / or a second electrical conductor.

[0054] Preferably, one or more pads are made of a thermally and electrically insulating material. The thermally insulating material preferably has a thermal conductivity of less than 30 W / mK, less than 20 W / mK, less than 10 W / mK, or even less than 5 W / mK at a temperature between 20°C and 1000°C.

[0055] Preferably, one or more pads have a melting point above 300°C, above 500°C, or above 1000°C, and are preferably made of a material selected from mica, mica derivatives, titanium, barium, mullite, cordierite, and alumina.

[0056] In one embodiment, discontinuities, preferably basic discontinuities, are created by fixing the measuring element to the carrier. Specifically, the carrier may surround or clamp the measuring element in a layered manner. In particular, the measuring element may be sandwiched between two fabrics, preferably between textile fabrics reinforced with a ceramic matrix. The irregularity of this fabric and the matrix of the ceramic matrix composite advantageously and unexpectedly allows for the creation of basic discontinuities.

[0057] Preferably, the impedance discontinuities are spaced apart by a distance measured along the waveguide, which is at least 10 times, preferably at least 15 times, and most preferably at least 20 times the reference wavelength. The reference wavelength is equal to the propagation speed of the interrogation signal (approximately 200,000 km / s for electromagnetic waves) divided by the frequency of the highest peak in the spectrum of the interrogation signal.

[0058] The present invention also relates to a method for manufacturing a furnace according to a first main embodiment, the method comprising the following steps:

[0059] i) Modify the measurement component of at least one waveguide (preferably a coaxial cable) to generate fundamental discontinuities randomly distributed along the waveguide;

[0060] ii) Integrating the at least one modified waveguide into or against the wall of the chamber of the glass manufacturing furnace;

[0061] iii) Connect the interrogator to the input of the at least one modified waveguide, which forms the filamentary electromagnetic waveguide.

[0062] To obtain a glass manufacturing furnace according to the first main embodiment.

[0063] Those skilled in the art know how to modify waveguides, particularly coaxial cables, to produce fundamental discontinuities. Through simple experimentation, they will be able to easily verify whether the echo returned from the discontinuity forms a fundamental secondary echo, and, for example, adjust the discontinuity by increasing texturing if the amplitude of the return from the discontinuity is insufficient to make the echo a fundamental secondary echo.

[0064] Preferably, step i) includes a change to the outer surface of the waveguide (preferably a coaxial cable), and preferably consists of a change to the outer surface of the waveguide, which is preferably achieved by texturing and / or segmenting the outer surface of the waveguide, for example by inserting pads.

[0065] The waveguide that is changed in step a) can be a commercial waveguide.

[0066] Step i) can be replaced by step i'), in which the fundamental discontinuity is generated simultaneously with the fabrication of the waveguide. Specifically, the fundamental discontinuity can be generated specifically by:

[0067] By texturing and / or segmenting the outer surface of the waveguide, for example by inserting pads onto the waveguide, and

[0068] By changing the composition of the dielectric material inserted between the first and second electrical conductors, and / or

[0069] By changing the composition of at least one of the first and second electrical conductors, and / or

[0070] By creating a raised surface on the surface of the dielectric material and / or on at least one of the first and second electrical conductors.

[0071] According to the second main embodiment, the furnace further includes one or more of the following optional features, and preferably includes all of the following optional features:

[0072] a) The measuring component of each waveguide of the array is parallel to the hot surface and extends at a distance such that, in use, i.e. when the furnace is operating normally, the measuring component is at a temperature above 500°C, preferably above 600°C, preferably above 700°C, preferably above 800°C, and / or below 1300°C, preferably below 1200°C, more preferably below 1100°C;

[0073] b) The maximum distance between the two measuring components of any two waveguides in the array is greater than 20 cm, preferably greater than 30 cm, preferably greater than 50 cm, preferably greater than 70 cm, preferably greater than 90 cm, and preferably less than 500 cm;

[0074] c) Insert at least one waveguide of the array, preferably each waveguide, into an aperture in the object, the aperture being configured to provide space for the thermal expansion of the waveguide;

[0075] d) At least one waveguide in the array, preferably the equivalent diameter of the measuring element of each waveguide is greater than 0.6 mm, preferably greater than 0.8 mm, preferably greater than 1 mm, and less than 50 mm, preferably less than 20 mm, preferably less than 10 mm, and preferably less than 5 mm;

[0076] e) The separation distance between the first and second electrical conductors of the measurement component of at least one waveguide of the array is greater than 0.3 mm, preferably greater than 0.4 mm, preferably greater than 0.5 mm, and less than 30 mm, preferably less than 10 mm, preferably less than 5 mm, and preferably less than 3 mm, which improves reliability and spatial resolution.

[0077] f) The measuring component has the following number of bends:

[0078] - If the length of the measuring component is less than 3 meters, then the measuring component has less than 2 bends per meter of length;

[0079] - If the length of the measuring component is greater than or equal to 3 meters, it has less than 1 bend per meter, preferably less than 0.5 bends per meter, and more preferably less than 0.1 bends per meter. This improves the integration of the waveguide while minimizing the risk of the waveguide breaking during its installation in the furnace.

[0080] Waveguide, preferably the measuring component of each waveguide preferably does not contain bends;

[0081] - The maximum curvature of the measuring component is such that its radius of curvature is at least 3 times, preferably at least 5 times, and preferably at least 10 times the equivalent diameter of the measuring component, which reduces the mechanical stress on the measuring component.

[0082] Preferably, at least one waveguide measurement component, and preferably the measurement component of each waveguide, is mounted to be able to slide relative to the object and / or relative to the carrier.

[0083] Through the study of numerous parameters, the inventors have discovered that this combination of features provides a solution to meet the specific limitations of glassmaking furnaces. In particular, this solution allows for the following objectives:

[0084] - Limit the risk of damaging the waveguide during installation;

[0085] - Monitor large objects, such as the bottom of a furnace;

[0086] - High robustness in use;

[0087] - Good spatial resolution;

[0088] - High measurement reliability;

[0089] - Real-time monitoring is performed throughout the furnace's lifespan without weakening the object or increasing the risk of contamination of the molten glass bath.

[0090] According to the third main embodiment, the first conductor and the second conductor are fixed to or integrated into a carrier, preferably a plate-shaped carrier, preferably a carrier formed of a ceramic matrix composite material, and preferably fixed to or integrated into the composite material by an interface layer or refractory filaments, nails, or strips. "Integration" means that the first conductor and the second conductor are incorporated into the composite material, for example, becoming weft or warp filaments of the fabric of the composite material.

[0091] Fixing the conductor in or on a carrier allows the conductor to be protected. The carrier is preferably arranged between the first layer and the back layer.

[0092] In a first preferred configuration, the carrier comprises a ceramic matrix composite material, and is preferably formed of the ceramic matrix composite material, and preferably, the first conductor and the second conductor are integrated into the fabric of the ceramic matrix composite material. Conductive filaments, preferably arranged substantially parallel and at predetermined intervals, may, for example, form weft filaments. Other filaments of the fabric (besides the first and second conductors) are preferably made of a dielectric material to avoid any electrical contact or short circuit between the conductive filaments.

[0093] In one implementation, other filaments (or “non-conductive filaments”) made of dielectric material can be randomly altered, for example by abrasion or chemical etching, to generate random basic discontinuities.

[0094] In supplementary or alternative embodiments, the first and second conductors are randomly altered, for example by abrasion or chemical etching, to generate random basic discontinuities.

[0095] In one embodiment, at least one of the first and second conductors is physically associated with one or more filaments made of a dielectric material, the filaments being, for example, randomly wound to generate random basic discontinuities.

[0096] In one embodiment, filaments made of a dielectric material are randomly added to the fabric.

[0097] In one embodiment, to generate random discontinuities, particularly basic discontinuities, the first and second conductors are woven into the fabric with the distance between them varying along the conductor. Preferably, the distance between two of the basic discontinuities is less than 10 cm, preferably less than 5 cm, and / or greater than 0.5 cm, and preferably greater than 1 cm. Preferably, the distance between two consecutive points of the first and second conductors located above or below the weft or warp mesh (multiple weft filaments or optionally intersecting warp filaments) of the woven fabric, preferably between two consecutive weft yarns, is less than 10 cm, preferably less than 5 cm, and / or greater than 0.5 cm, and preferably greater than 1 cm.

[0098] In one implementation, to generate random base discontinuities, particles and / or fibers of random size and / or random shape and / or random dimensions, and / or spatially randomly distributed particles and / or fibers, are arranged to contact the fabric prior to impregnation with the matrix precursor. Irregularly textured textile webs can also be used as the fabric.

[0099] In the second configuration, the first conductor and the second conductor are fixed to the surface of the carrier, and preferably, the carrier comprises a ceramic matrix composite material, and is preferably formed of a ceramic matrix composite material.

[0100] According to one possible implementation, at least one waveguide, preferably a conductor of each waveguide, and preferably a measuring component are fixed to a carrier via an interface layer. The interface layer is a layer made of a material having a coefficient of thermal expansion (CTE) between that of the carrier (particularly the CTE of the ceramic matrix of the carrier) and the CTE of the material forming the conductor. Preferably, the interface layer comprises NiCrAlY or is even composed of NiCrAlY.

[0101] According to another possible implementation, at least one waveguide, preferably the conductor of each waveguide, and preferably the measuring component are attached or fixed to a carrier by means of refractory filaments, nails or strips, the carrier preferably being in the form of a plate.

[0102] In one embodiment, the measuring component is protected by a coating made of a dielectric material, preferably a polymer, or more preferably a ceramic, which surrounds a conductor, preferably separated by the dielectric material. The coating can be straight or curved. It can be flexible or rigid to give the measuring component, or even the transmission component, a certain shape.

[0103] In one implementation, such as Figure 12 As shown, the carrier precursor, preferably formed of a ceramic matrix composite precursor 40' (typically a prepreg material), is wound around the first and second conductors, at least in the measuring component. Before or after the matrix precursor cures, the instrumented carrier precursor or instrumented carrier is preferably inserted into a protective coating 27, which is preferably ceramic.

[0104] It is particularly advantageous to attach or integrate the waveguide's measurement components onto or into a ceramic matrix composite, not only because the ceramic matrix composite protects the measurement components, but also because, through construction, even when the ceramic matrix composite includes textiles, it possesses an irregular microstructure that can generate many fundamental discontinuities.

[0105] According to the fourth main embodiment, at least one waveguide, preferably each waveguide's measuring component, is movable such that its dimensions can be varied under the influence of temperature changes during use. Preferably, the measuring component is slidably mounted relative to the object, and more preferably slidably mounted in a housing, particularly in an aperture formed in the object or preferably in a carrier.

[0106] Preferably, the shell retains space for thermal expansion, which is preferably formed by removing sacrificial material, with at least a portion of the object or carrier formed around the sacrificial material.

[0107] Slippage can also be caused by the presence of a solid lubricant (preferably graphite) around the measuring component.

[0108] Due to the incompatibility between the material of the object or carrier that defines the housing and the measuring component on the other hand, for example due to the high porosity of the material of the object defining the housing, the measuring component may not adhere to the wall of the housing.

[0109] Slippage can also be caused by the insertion of the measuring element into the protective coating (preferably a non-segmented coating). In practice, segmenting the protective coating by placing a series of dielectric beads along the measuring element often enhances signal attenuation.

[0110] The present invention also relates to a method for manufacturing a furnace according to the invention, wherein, for at least one waveguide of an array, preferably for each waveguide, the method comprises the following sequential steps:

[0111] 1) Insert the sacrificial material between the following:

[0112] - Waveguide measurement components, and

[0113] - The object or its precursor, or carrier, particularly a ceramic matrix composite or carrier precursor, then

[0114] 2) In cases where sacrificial materials have been inserted into the precursor of the object or the precursor of the carrier, the sacrificial materials are removed after or simultaneously with the manufacture of the object or carrier to create the space for measuring the expansion of the component.

[0115] In one embodiment, the sacrificial material is the material that covers the sacrificial coating of the measuring component, and in order to insert the sacrificial material,

[0116] - To manufacture an object or carrier around a measuring component, preferably by casting a precursor of the object around the measuring component and then sintering it, or by inserting the measuring component into a precursor of the carrier and then sintering the precursor of the carrier around the measuring component.

[0117] - A housing, in the form of a groove or hole (or orifice), optionally a through groove or through hole, is formed in the object or the precursor of the object or in the carrier or the precursor of the carrier. The measuring component is then inserted into the housing, and the housing is then filled with an unformed refractory product (i.e., powder or paste), preferably refractory concrete, wherein the refractory concrete contains an adhesive, preferably a hydraulic adhesive, preferably cement, and is capable of curing by activation of the adhesive. The unformed refractory product is then cured.

[0118] The precursor to the object can be a preform for sintering or a powdered mixture that can be cured by a chemical reaction. The carrier precursor can be a ceramic matrix composite precursor containing a matrix precursor of fabric and impregnated fabric, or "prepreg material".

[0119] Measuring components with sacrificial cladding can be embedded in the precursor of an object or carrier during their manufacture. Alternatively, the shell can be formed in the object or the precursor of the object or the carrier or the precursor of the carrier, and the measuring components with sacrificial cladding can be embedded in unformed refractory material.

[0120] In one implementation, the sacrificial material is a waveguide-independent filler material (i.e., unlike the sacrificial cladding, the sacrificial material is not initially fixed to the waveguide), and in order to insert the sacrificial material,

[0121] - A housing, in the form of a groove or hole, optionally a through slot or through hole, is formed in the object or the precursor of the object or the carrier or the precursor of the carrier, and then

[0122] - Insert the measuring component into the housing, then

[0123] - The housing is filled with filler material to embed the measuring component; the amount of filler material allows for the formation of an expansion space.

[0124] - Fill the remaining portion of the shell with the unformed refractory product, preferably refractory concrete, and then

[0125] - To solidify unformed refractory products.

[0126] In step 2), the sacrificial material is preferably removed by heat treatment, preferably by heat treatment of a precursor for a solidified object or carrier, and preferably by sintering. The sacrificial material is preferably removed by heating during furnace heating and / or during sintering of the unformed refractory product or object precursor or carrier precursor, at a temperature preferably between 400°C and 1200°C. Sintering can be caused by furnace heating.

[0127] Sacrificial materials can be removed by evaporation or combustion.

[0128] Therefore, sacrificial materials leave room for thermal expansion.

[0129] Preferably, the sacrificial material is an organic material, preferably a polymer. Upon degradation, this sacrificial material advantageously generates residual carbon that limits the oxidation of the first and second conductors, allowing its use in an oxidizing atmosphere.

[0130] The manufacturing method may also include one or more of the following optional and preferred features:

[0131] - Step 1) and / or Step 2) are performed in situ (i.e., in the part of the furnace to which the measuring component is intended for use in the furnace);

[0132] - The shell may be formed in the carrier or the precursor of the carrier, but it may also be formed in the back layer of the object or the precursor of the back layer;

[0133] - The sacrificial cladding of the waveguide, preferably the sacrificial cladding of each waveguide, is made of a polymer, preferably a halogen-free and / or nitrogen-free and / or silicon-free polymer, preferably a polyolefin, preferably polyethylene or a derivative thereof;

[0134] - The filler material is resin;

[0135] - Remove sacrificial material while curing the precursor of the object or carrier to obtain the object or carrier respectively.

[0136] In one implementation, step 1) includes the following steps:

[0137] - Place the array precursor in its usage location, that is, arrange one or more measuring components in the desired usage location during furnace operation;

[0138] - Prepare starting fillers with the required composition for the object or support, considering only refractory oxides in this regard;

[0139] - Deposit starting filler to embed array precursors and obtain precursors for objects or carriers.

[0140] In one embodiment, at least one measuring component, preferably each measuring component, is protected by a protective coating, preferably a ceramic protective coating. A sacrificial coating covers the protective coating.

[0141] According to the fifth main embodiment, the waveguide includes a protective cladding that protects the first electrical conductor and the second electrical conductor.

[0142] The protective cladding can be rigidly attached to the conductor, provided that the protective cladding is segmented or forms a rigid sheath that serves as a housing for the waveguide. The waveguide can be inserted into the sheath after it has been placed in its intended position. In particular, the sheath can be included in the object during its manufacture, for example, placed in place before being embedded in the concrete composition of the object.

[0143] Preferably, the waveguide is able to move freely within the sheath. The protective cladding can also form the expansion space as described above.

[0144] Rigid sheaths can advantageously guide waveguides to have a predetermined shape (e.g., a straight or curved shape) or guide waveguides over long lengths during their insertion.

[0145] Preferably, the waveguide is protected by two protective claddings: a segmented protective cladding, preferably formed of a plurality of abutment pads; and a rigid protective cladding, which serves as the shell of the waveguide. The segmented protective cladding can, for example, be produced by a plurality of through-beads.

[0146] The present invention also relates to a method for manufacturing a glass manufacturing furnace according to the invention, wherein, for at least one waveguide in an array, and preferably for each waveguide in the array, the method comprises the following steps:

[0147] A) Prepare a ceramic matrix composite precursor including a ceramic matrix precursor, preferably in the form of a plate, and integrate the waveguide measurement component into or onto the ceramic matrix composite precursor to obtain an instrumented carrier precursor;

[0148] B) Curing and / or firing, preferably sintering the instrumented carrier precursor, preferably during furnace heating, to obtain the instrumented carrier through the consolidation of the ceramic matrix precursor, the ceramic matrix precursor preferably being in the form of an instrumented plate;

[0149] C) If step C) is after step B), then the instrumented carrier is installed; or if step C) is before step B), then the instrumented carrier precursor is installed, preferably between the back layer defining the hot surface and the furnace heating system, and preferably installed substantially parallel to the hot surface.

[0150] Preferably, step A) preferably includes the following steps:

[0151] a) Prepare a ceramic matrix precursor in the form of a slurry containing ceramic particles and / or precursors of ceramic particles, wherein the material of the ceramic particles has a dielectric constant or relative permittivity greater than 3 and / or less than 30, and preferably less than 15, relative to vacuum at 25°C and atmospheric pressure (preferably measured at 1 MHz).

[0152] b) Independent of step a), fix or integrate the first and second electrical conductors of the measuring component into a fabric, preferably in the form of one or more filament textiles or meshes, preferably ceramic filaments, the fabric being made of a material having a dielectric constant or relative permittivity greater than 3 and / or less than 30, and preferably less than 15, relative to vacuum at 25°C and atmospheric pressure (preferably measured at 1 MHz).

[0153] c) Impregnate the fabric with the slurry.

[0154] Before or preferably after step B), a connector capable of electrically connecting the conductor to the interrogator is installed.

[0155] In one embodiment, the measuring component or even the transmission component is protected by the coating before it is fixed to or integrated into the carrier.

[0156] In one embodiment, in step B), the temperature at which the instrumented carrier precursor is fired is from 400°C to 1200°C.

[0157] In one specific embodiment, step B) is carried out in an oven or furnace before step C), preferably in air or preferably in a controlled atmosphere.

[0158] In one embodiment, in step C), the instrumented carrier precursor is mounted on or in the object precursor, and in step B), the instrumented carrier precursor is solidified while the ceramic matrix precursor is being converted into the ceramic matrix and the object precursor, so as to convert it into the object.

[0159] In one embodiment, in step C), the instrumentation carrier or instrumentation carrier precursor, preferably in the form of a plate, is arranged between:

[0160] - The measuring component, and

[0161] - An object or a precursor to an object.

[0162] Of course, the features of each of the main aspects can be combined. Preferably, the features of each of the main aspects are combined.

[0163] Regardless of the primary implementation, the waveguide array of the glass manufacturing furnace according to the present invention may also have one or more of the following optional and preferred features:

[0164] - The waveguide array is at least partially, and preferably entirely, located in:

[0165] - Within the refractory backing layer, this refractory backing layer is located behind the first layer formed by the assembly of refractory bricks defining the hot surface of the object, or

[0166] - Within the refractory sublayer of the back layer;

[0167] - Measurement components for the waveguide, and preferably the measurement components for each waveguide are located in the back layer or in a sublayer of the back layer, preferably behind the blocking sublayer;

[0168] - The sublayer is: an insulating sublayer that contacts the cold surface of the object and serves to define the heat distribution of the lining; or preferably a barrier sublayer that serves to neutralize the molten glass in the event that the furnace (particularly the bottom of the furnace) is penetrated;

[0169] - Preferably, when the object is the bottom of the furnace, the waveguide's measuring component, and preferably the measuring component of each waveguide, is located between the blocking sublayer and the insulating sublayer;

[0170] - The measurement components of the arrayed waveguides, and preferably the measurement components of each waveguide in the array, extend into the housing, which is preferably in the form of an aperture formed in the object and defines space for the thermal expansion of the waveguide;

[0171] - The space for thermal expansion is configured such that the waveguide's measurement components are not compressed by the object due to changes in the dimensions of the object and the measurement components caused by temperature variations during use;

[0172] - Preferably, the ratio of the equivalent diameter of the housing to the equivalent diameter of the measuring component is greater than 1.05, preferably greater than 1.10, preferably greater than 1.20, and / or less than 3.00, and preferably less than 2.50;

[0173] - The housing is an opening, the diameter of which is smaller than the thickness of the layer or sublayer in which the measuring component is placed;

[0174] - The diameter of the orifice is less than 70% or even less than 50% of the thickness of the layer or sublayer;

[0175] - Measurement components that do not include curved waveguides, preferably each waveguide's measurement components are at least partially, preferably completely parallel to the other waveguide;

[0176] - Measurement components of at least one waveguide of the array, and preferably each waveguide measurement component does not contain bends;

[0177] - The maximum distance between the measurement components of any two waveguides is less than 200cm;

[0178] - Multiple measurement components of multiple waveguides are formed together to form a network extending on a curved or flat surface (preferably a flat surface);

[0179] - The measuring components of the net are spaced apart by distances greater than 1cm, greater than 5cm, greater than 10cm, greater than 20cm, and / or less than 100cm, less than 80cm, or less than 50cm.

[0180] - The measuring components of the net are parallel to or intersect each other without contacting each other;

[0181] - The furnace includes more than one, more than two, preferably more than three, and preferably more than five meshes, which are preferably parallel to each other, preferably parallel to the hot surface, and preferably regularly spaced apart in a direction perpendicular to the hot surface. The distance between two consecutive meshes is preferably less than 10 cm, 5 cm, or 2 cm, which advantageously allows for the evaluation of the heat flux through the object.

[0182] - At least one measuring element of the array, and preferably more than half of the measuring elements extend in a direction perpendicular to the flow direction of the molten glass when in use;

[0183] - The radius of curvature of the measuring component of the waveguide array, and preferably the radius of curvature of each waveguide in the array at each point is at least 3 times, preferably at least 5 times, and more preferably at least 10 times the equivalent diameter of the measuring component;

[0184] - Waveguides of the array, and preferably each waveguide is exposed on the cold side (the side opposite the hot side) of the object or on the side of the object that is colder than the hot side (especially when the object is the bottom of a furnace).

[0185] Those skilled in the art know how to define the dimensions of the shell used for measuring components to allow adequate space for thermal expansion. For example, in the case of the bottom of a furnace, they would consider the thermal gradient at the bottom, the coefficient of thermal expansion of the slab and the measuring component, and their dimensions.

[0186] The dimensions of the shell are also designed so that the object and the waveguide can expand independently of each other, and specifically so that the elongation or retraction of the object does not exert stress on the waveguide, or vice versa.

[0187] Regardless of the primary implementation method, the waveguides of the array, preferably each waveguide, may also have one or more of the following optional and preferred features:

[0188] - The waveguide satisfies the conditions for Rayleigh scattering, which makes it easier to locate the region of the fundamental secondary echo reflected;

[0189] - At least in the measuring component, at least one spacer is arranged between two adjacent pads, and preferably between the pads of each pair of two adjacent pads, the at least one spacer being made of an electrically insulating material that is more deformable than the material of the pads;

[0190] - The spacers, and preferably each of the spacers:

[0191] - Made of elastically compressible material in a spring-like manner, and / or

[0192] - Contains organic materials and / or is composed of organic materials, preferably polymeric materials, such as polyethylene or silicone-based polymeric materials, preferably selected from elastomers, thermoplastic materials and heat-shrinkable materials, and in the form of foam or adhesive, for example;

[0193] - The length of the measuring component and / or waveguide is greater than 1 meter, preferably greater than 2 meters, preferably greater than 3 meters, or even greater than 10 meters, and / or less than 30 meters, and preferably less than 20 meters;

[0194] - The length of the transmission component is preferably greater than 0.1 meters and / or less than 5 meters, or even less than 2 meters;

[0195] - The first and second electrical conductors are parallel, which allows for robustness, efficiency, and low cost;

[0196] - The first and second electrical conductors are coaxial, which limits the volume and increases the stability of the distance between the conductors. The dielectric material holds the two coaxial conductors in place.

[0197] - The first and second electrical conductors are straight lines, which facilitates integration into the object;

[0198] - The equivalent diameters of the first and second conductors are greater than 0.4 mm, greater than 0.5 mm, preferably greater than 1 mm, and / or less than 50 mm, preferably less than 20 mm, preferably less than 10 mm, and preferably less than 5 mm, which allows for improved signal quality (low attenuation) while reducing the risk of the object becoming weakened or broken;

[0199] - The first and second electrical conductors are separated from each other by a dielectric material that belongs to the object and, for example, to an electrical insulating layer;

[0200] - The first and second electrical conductors comprise, or are preferably composed of, refractory metals or metal alloys, such as silver available up to 800°C, or inconel (e.g., Alloy 625 and Alloy 690) available up to 1100°C, or FeCr (e.g., Kanthal APM) available up to 1425°C, such as that supplied by Kanthal, or preferably a noble metal or alloy of these elements selected from platinum, tungsten, gold, palladium, rhodium, ruthenium, iridium, platinum may be doped, preferably with 0.001% to 5% of oxides of zirconium, hafnium, calcium, magnesium or yttrium;

[0201] - The dielectric material separates the first conductor and the second conductor, and comprises or is composed of oxides of at least one element selected from Al, Zr, Mg, Ca, Ti and Si;

[0202] - In the temperature range of the environment in which the measuring component is used, preferably between 20°C and 1000°C, the materials used to make the first and second electrical conductors have a resistivity of less than 10 microohm-meters.

[0203] - The dielectric material separating the first conductor and the second conductor has a dielectric constant or relative permittivity greater than 3 and / or less than 30 and preferably less than 15 relative to vacuum at 25°C and atmospheric pressure (preferably measured at 1MHz);

[0204] - The dielectric material contains an oxide of at least one element selected from Al, Zr, Mg, Ca, Ti and Si;

[0205] - At least a portion of the measuring component, preferably at least in the region of the component where the waveguide is not inside the object, is protected by a protective member, which is, for example, in the form of a tube, perforated brick, or slotted brick, and preferably a protective cladding, preferably a ceramic cladding, partially and preferably completely surrounding the measuring component.

[0206] - The protective coating is made of an oxide of at least one element selected from Al, Zr, Mg, Ca, Ti and Si;

[0207] - The waveguide is connected to the interrogator at each of its two ends;

[0208] - The waveguide is exposed on the cold side (the side opposite the hot side) of the object or on the side of the object that is cooler than the hot side;

[0209] - The first conductor and the second conductor are fixed to a plate-shaped carrier (preferably formed of a ceramic matrix composite material), preferably by means of an interface layer or refractory filaments, nails or strips, or integrated into the composite material.

[0210] Regardless of the primary implementation, at least one spacer made of a material more easily deformable than the pad material is preferably arranged between two adjacent pads. Preferably, at least in the measuring component, the spacer is arranged between the pads of each pair of adjacent pads. Preferably, the material of the spacer is elastically compressible in a spring-like manner. The spacer, and preferably each spacer, is preferably in the form of a spring or a washer. The spacer, and preferably each spacer, comprises or is composed of the following materials: organic materials, preferably polymeric materials, preferably thermoplastic or heat-shrinkable materials, or polymer foams.

[0211] Preferably, in the measuring component, the spacer is disposed on the first electrical conductor and / or the second electrical conductor.

[0212] Inserting spacers between the pads advantageously ensures a minimum spacing between them, especially when the waveguide is curved. In particular, the spacers limit the risk of breakage when the waveguide is wound, for example, onto a mandrel or into a coil (considering its transport) and when the waveguide is placed in its place of use.

[0213] Regardless of the primary implementation, the interrogator may also have one or more of the following optional and preferred features:

[0214] - The interrogator is configured to determine the object's temperature, wear level, and / or wear rate based on the analysis of the response signal;

[0215] - The interrogator is configured to predict the occurrence of molten glass penetrating or immersing into the object, or the sudden movement or deterioration of the lining;

[0216] - The furnace preferably includes at least one thermocouple, which is arranged at a distance of less than 10 cm from the waveguide (preferably from each waveguide), for example, in the region where the furnace temperature is between 500°C and 1500°C when the furnace is in use, to calibrate the waveguide for indirect temperature measurement.

[0217] The present invention also relates to a method for monitoring the state of an object in a glass manufacturing furnace according to the present invention, the method comprising the following steps:

[0218] a. To manufacture a glass-making furnace according to the present invention;

[0219] b. For each waveguide, control the interrogator connected to the waveguide such that the interrogator injects an interrogation signal through the input terminal of the waveguide;

[0220] c. Analyze the response signal to determine information related to the state of the object in the region of the waveguide's measurement component.

[0221] According to one particular implementation, information relating to the state of an object is the remaining thickness of the refractory material or the temperature at one or more points on the object. Attached Figure Description

[0222] Other features and advantages of the invention will become clearer from the following detailed description and study of the accompanying drawings, wherein:

[0223] [ Figure 1 ] Figure 1 A schematic half-section of a glass-making furnace is shown;

[0224] [ Figure 2 ] Figure 2 An example of a monitoring device according to the invention in its place of use is schematically shown;

[0225] [ Figure 3 ] Figure 3 Various possible implementations of waveguides including pad beads are shown;

[0226] [ Figure 4 ] Figure 4 The bottom of the glass-making furnace according to the invention, as viewed from above, is shown;

[0227] [ Figure 5 ] Figure 5 The conventional structure of the bottom of a glass-making furnace is shown in cross-section;

[0228] [ Figure 6 ] Figure 6 The bottom of the glass-making furnace according to the invention in a first preferred embodiment is shown in cross-section;

[0229] [ Figure 7 ] Figure 7 The bottom of the glass-making furnace according to the invention in the second embodiment is shown in cross-section;

[0230] [ Figure 8 ] Figure 8 An array of waveguides in the top of a glass-making furnace according to the invention, in a preferred embodiment, is shown in cross-section;

[0231] [ Figure 9 ] Figure 9 An example of a response signal is shown;

[0232] [ Figure 10 ] Figure 10 A carrier plate for incorporating a measuring component according to an embodiment of the present invention is shown;

[0233] [ Figure 11 ] Figure 11 A plate-shaped carrier is shown as an incorporation measuring component according to another embodiment of the present invention;

[0234] [ Figure 12 ] Figure 12 The method of manufacturing a carrier by winding a carrier precursor around a measuring component is shown.

[0235] In the various figures, the same reference numerals are used to indicate the same or similar elements. Detailed Implementation

[0236] Definitions

[0237] "Object" refers to the refractory component of the furnace equipped with monitoring equipment. The object is preferably the furnace lining or an element of the first layer (viewed from inside the furnace), which is typically obtained by assembling bricks, such as for the sidewalls, top, or bottom of the furnace chamber. The first refractory layer is typically made of fused or dense sintered material to withstand temperature and corrosion from molten glass and / or its vapors.

[0238] A "hot surface" is the surface of an object exposed to the space within a furnace that holds or is used to hold molten glass. The hot surface may or is intended to contact the molten glass and / or the gaseous environment above it. Therefore, a hot surface is the surface of an object subjected to or intended to be subjected to the highest temperatures. The hot surfaces of all the bricks on the sidewalls of a glass melting furnace can also be broadly considered "hot surfaces." The upper surface of the bottom can also be considered a "hot surface." The adjective "hot" is used for clarity.

[0239] Conventionally, the “thickness” of an object is its dimension measured in a direction perpendicular to its hot surface or in the direction of “depth.” For example, for the furnace side bricks in contact with molten glass, the thickness is measured in a direction pointing roughly horizontally to the molten glass bath. For the furnace bottom, the thickness is measured in the vertical direction.

[0240] Two objects are considered to have "substantially identical composition" when at least 80%, preferably at least 90%, of their components are the same.

[0241] Concrete typically consists of a group of coarse particles bound together by a matrix. These particles are larger than 50 μm in size, typically between 50 μm and 25 mm, and the matrix ensures a substantially continuous structure between the coarse particles. The matrix is ​​composed of “matrix particles” with a size less than or equal to 50 μm.

[0242] Activation is the process by which most of the fresh concrete hardens. Fresh concrete is typically produced from a granular mixture containing a hydraulic binder, wetted by water or another liquid, and preferably additionally more than 3 wt% water. For shaping, if the mixture is not self-compacting, the fresh concrete is preferably cast, vibratory cast, or even sprayed.

[0243] "Hydraulic binder" refers to an adhesive that, upon activation, typically results in hydration, curing, and hardening at room temperature. Cement is a hydraulic binder. Alumina cement is an example of cement. Calcium aluminate cement is an example of alumina cement.

[0244] Refractory "rammed mixtures" are refractory mixtures containing chemical and / or ceramic and / or organic binders, which are typically (possibly after wetting) shaped by ramming, compacting, or compacting by hand or using suitable mechanical means. Preferably, the granular mixture is non-wetting ("dry") or wetted with less than 3 wt% water.

[0245] A “carrier” is a component added to an object, and one or more waveguide measurement components are arranged on or within the carrier. The carrier physically protects the measurement components, preferably creates a base discontinuity, and preferably allows the measurement components to slide, especially under the influence of temperature.

[0246] When a carrier or carrier precursor carries at least one waveguide measurement component, the carrier or carrier precursor is sometimes considered "instrumented".

[0247] The plate typically has two substantially parallel main surfaces, and the thickness between the two main surfaces is typically less than 1 / 2, or even less than 1 / 3, or even less than 1 / 5, or even less than 1 / 10, or even less than 1 / 100 of the width of the main surfaces. The plate can be flat or curved. The shape of the plate-like carrier is preferably configured to match the shape of the object to which it is used to be fixed.

[0248] "Ceramic matrix composite" or "CMC" generally refers to a product consisting of fibers and / or filaments bonded together by a ceramic matrix, preferably comprising at least 30 vol% of the CMC. The selection of fibers and / or filaments depends on the environment in which the ceramic matrix composite must be placed, particularly on conditions of temperature, corrosion, thermal cycling and expansion, as well as on the nature of the refractory components of the furnace to be fitted.

[0249] The layout of the fibers and / or filaments chosen to form the structure of the reinforcing matrix depends on the desired shape of the ceramic matrix composite and the ease with which the waveguide must be attached to it. For example, the textile or web stacking of fibers is well-suited for simple plates, filament winding is well-suited for plates with rotational geometry, and filament placement is well-suited for complex shapes in large dimensions.

[0250] Ceramic matrix composites are typically manufactured by heating, preferably to over 600°C, and more preferably to over 700°C, and more preferably by sintering.

[0251] Fibers and / or filaments are typically in the form of fabrics. CMC can be identified as "ceramic matrix fabric".

[0252] The fabric can be:

[0253] - An ordered two-dimensional structure of fibers or filaments, especially in knitted, woven, or textile fabrics, or

[0254] - A random two-dimensional structure of fibers or filaments, which is not preferred.

[0255] In particular, fabrics differ from fiber mats, where the organization of fibers or filaments is random in all three dimensions of space.

[0256] A "fiber" is a filament whose length is more than five times its equivalent diameter. The "diameter" of a fiber is the diameter of a disk with the same cross-sectional area at its midpoint.

[0257] A filament is an aggregate of fibers that contains more than 10 and preferably less than 500,000 fibers in its cross-section, and the length of the filament is more than 5 times its diameter.

[0258] "Filamentous" refers to "a general shape having filaments." For example, cables have a filamentous shape. Narrow strips or "bands" are considered filamentous. The length of an object having a filamentous shape is preferably more than 10, 100, 1000, or 10000 times its width (i.e., the maximum dimension of the object in a plane perpendicular to its length direction).

[0259] A waveguide is a thin, filamentary transmission line, distinct from the object being measured, that guides electromagnetic waves derived from very high-frequency electrical signals for measurement using electrical time-domain or frequency-domain reflection methods. A waveguide typically comprises at least two electrically isolated conductors that extend along its length. The interrogation signal is typically a change in the potential difference between the conductors. The interrogation signal is injected at the input of the waveguide and then propagates as an electromagnetic wave. Changes in impedance cause partial reflection of this wave. The reflected response signal is also a time-dependent change in the potential difference between the conductors.

[0260] The term "echo" is used to refer to a portion of the response signal that is reflected by the following:

[0261] - Discontinuity point (secondary echo).

[0262] - The input end of the waveguide, where the waveguide connector is connected to the interrogator (transmitting the echo), or

[0263] - Waveguide output (terminal echo 4 - see Figure 9 ).

[0264] Therefore, the secondary echo is a response to the discontinuity of the interrogation signal. The secondary echo can be a "noise" secondary echo (5), a "basic" secondary echo (6), or a "hard" secondary echo (7). Figure 9 ).

[0265] Noise secondary echoes are secondary echoes with an amplitude less than or equal to 0.5% of the amplitude of the terminal echo, and preferably greater than 0.0001%, more preferably greater than 0.01%, and more preferably greater than 0.1% of the amplitude of the terminal echo. Noise secondary echoes are typically generated by "noise" discontinuities caused by defects in the waveguide, particularly defects generated during the waveguide's manufacturing process.

[0266] Because noise secondary echoes have low amplitude, they attenuate very quickly. In many cases, noise secondary echoes cannot accurately monitor and measure changes, such as when temperature rises or humidity is high.

[0267] The fundamental secondary echo is a secondary echo generated from a "fundamental" discontinuity, typically created by intentional alterations to the waveguide (e.g., texturing or adding pads). Preferably, the amplitude of the fundamental secondary echo is less than the amplitude of the terminal echo, and more preferably less than 90%, 70%, 50%, and 30% of the amplitude of the terminal echo. When the length of the measuring component is less than 10 meters, the amplitude of the fundamental secondary echo is preferably greater than 0.5% of the amplitude of the terminal echo, more preferably greater than 1% of the amplitude of the terminal echo, and less than 30% of the amplitude of the terminal echo.

[0268] The amplitude of the primary secondary echo can be 2%, 3%, or 5%, or even 10%, greater than the amplitude of the terminal echo reflected from the output end of the waveguide.

[0269] A hard secondary echo is a secondary echo with an amplitude greater than or equal to 30% of the terminal echo amplitude. Hard secondary echoes are typically isolated and generated by "hard" discontinuities, which are usually caused by significant or abrupt changes in the waveguide structure, such as unexpected degradation of the waveguide (e.g., due to cracking (not fracture)). Such hard local discontinuities do not allow for the measurement of environmental disturbances or changes other than the location of the hard discontinuity by analyzing hard secondary echoes. Therefore, hard local discontinuities do not allow for the measurement of changes over the entire length of the measurement component.

[0270] However, recent research by the inventors has demonstrated that if the number of discontinuities in the generation of hard secondary echoes per meter of waveguide measuring component is greater than 10, greater than 15, greater than 20, greater than 30, greater than 40, or greater than 50, and preferably less than 10,000, and if these discontinuities are randomly distributed, then the hard secondary echoes generated by the discontinuities can form a fundamental secondary echo that can be used to monitor the state of furnace components by electrical time-domain or frequency-domain reflection methods.

[0271] A "discontinuity point" or "impedance discontinuity point" is a part of a waveguide that is able to reflect a specific echo in response to an interrogation signal, preferably in the form of a small change in potential. The echo is altered when the impedance of the discontinuity point changes, and especially when it is subjected to changes in the properties of its local environment (i.e., in the region of the discontinuity point).

[0272] In particular, the impedance at a discontinuity will change when the shape of the waveguide and / or the properties of the local temperature and / or the local environment (i.e., around the discontinuity) are altered. If only one of the factors causing the change at the discontinuity changes, such as a change in the local temperature, then there will therefore be a relationship between the impedance (and therefore the echo) and the value of that factor.

[0273] In particular, discontinuities can be caused by local variations in the structure and / or composition of the waveguide, and especially by local variations in one of the conductors of the waveguide and / or the dielectric material disposed between the conductors.

[0274] "Sacrificial coating" refers to a coating that is at least partially decomposed, preferably due to heat treatment decomposition.

[0275] For clarity, a distinction is made between protective cladding used for preservation during use and sacrificial cladding or “temporary” cladding, which is used to create space for the thermal expansion of the waveguide and is therefore intended to be removed.

[0276] The equivalent diameters of the waveguide, measurement component, conductor, or housing are the maximum cross-sectional diameters of the waveguide, measurement component, conductor, or housing, respectively. Considering each cross-section (i.e., the section perpendicular to the longitudinal direction) along the waveguide, measurement component, conductor, or housing, the cross-sectional diameter measured for the cross-section is the diameter of a disk having the same area as the cross-section.

[0277] When the cross-section remains constant, the equivalent diameter is therefore equal to the cross-sectional diameter, and is independent of the cross-section in question.

[0278] A “bend” is an area of ​​a measuring component where the measuring component changes direction by more than 45° over a length of less than 80 cm.

[0279] The "precursor" of a component is the object that is transformed into the component during the furnace manufacturing process. For example, a preform of an object is a precursor to the object, which is transformed into the object during sintering.

[0280] "Preformed component" refers to a component formed or prefabricated from a granular mixture, such as concrete (typically by casting and vibration) or a tamping mixture (typically by tamping), and is compacted by heat treatment and, for example, by sintering. Methods for manufacturing preformed components are well known to those skilled in the art. Typically, granules of refractory powder are mixed with a temporary binder, and the mixture is shaped into the desired form.

[0281] The adjectives "first" and "second" are used merely for clarity.

[0282] Unless otherwise stated, “conductor” refers to the first or second electrical conductor of the waveguide.

[0283] The term "local" or "partially" is used to define a feature or action that relates only to a portion of the waveguide, such as a feature or action related to a length less than 5 cm, 1 cm, or 1 mm. Therefore, a "local" change in a property means that the value of that property changes within that portion, for example, by more than 5% or more than 10%. This change can, for example, be less than 500%.

[0284] Generally, "ceramic material" refers to a material that is neither metal nor organic. In a preferred embodiment, oxide glasses and carbon (in various forms, whether crystalline or not) are considered ceramic materials.

[0285] The terms “including,” “contains,” and “have” should be interpreted broadly and without limitation.

[0286] Detailed description

[0287] This invention utilizes the known principles of electrical time-domain reflectometry (E-TDR) or electrical frequency-domain reflectometry (E-FDR).

[0288] Typically, a transmitter sends an interrogation signal in the form of a pulse into a conductive medium. The conductive medium returns a reflected response signal, which is then analyzed to infer information about the conductive medium.

[0289] Specifically, the temperature experienced by the measuring component depends on the environment of the object, particularly molten glass or its vapor, but also on the thickness of the material separating the object from that environment. When the thickness at a point on the object decreases, the measuring component can be observed to exhibit changes in its localized response when receiving interrogation signals.

[0290] This localized response allows the interrogator to be informed of a reduction in the object's thickness, or even of molten glass penetrating into the object at the point of problem.

[0291] Monitoring device

[0292] Electromagnetic waveguide

[0293] Waveguide 12 ( Figure 2 The waveguide 12 is in the form of a transmission line, such as a general form of a strip or cable, extending from the input terminal 12e to the output terminal 12s. The waveguide 12 includes:

[0294] - Measuring component 14, which includes discontinuities for measurement, and

[0295] - Transmission component 15, which is used to connect the measuring component 14 to the interrogator 18.

[0296] The measuring component is designed to withstand the temperature it experiences during use, and preferably to withstand temperatures of 200°C, and even more preferably to withstand temperatures of 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C or 1200°C.

[0297] The length of the waveguide, and preferably the length of the measuring component, is preferably greater than 1m, preferably greater than 2m, preferably greater than 5m, preferably greater than 10m, greater than 15m, greater than 20m, and / or less than 200m, or even less than 100m, preferably less than 50m.

[0298] Preferably, the conductor, and preferably each conductor, or even the waveguide, has a diameter of less than 10 mm, less than 5 mm, and / or preferably greater than 0.4 mm, preferably greater than 0.5 mm, preferably greater than 1 mm:

[0299] - Equivalent diameter, or

[0300] - For conductors or waveguides in strip form, thickness.

[0301] The waveguide includes a first electrical conductor 121 and a second electrical conductor 122, which may take the form of a cable, cable assembly or strip including one or more conductors, for example.

[0302] Each conductor has:

[0303] - The input terminal (i.e., located at the input of the waveguide) is electrically connected to the corresponding terminal of the interrogator 18; and

[0304] - The free output terminal located at the output end of the waveguide.

[0305] The output terminals are not electrically connected to each other, so the conductors do not form a circuit (such as in a resistance measuring device, where DC or AC current flows through the circuit).

[0306] The conductor material is preferably a conductive metal such as Al or Cu, or steel or a metal alloy. The conductor material can also be ceramic or cermet. In particular, for applications in high-temperature environments, the conductor can be made of the following:

[0307] - Inconel alloys (such as Alloy 625 and Alloy 690) can be used at temperatures up to 1100°C.

[0308] - Platinum,

[0309] - FeCr supplied by Kanthal (e.g., Kanthal APM) can be used at temperatures up to 1425°C.

[0310] - Tungsten,

[0311] - Rhodium,

[0312] - Ruthenium,

[0313] - Palladium, or

[0314] - Iridium.

[0315] Conductors made of metals coated with conductive refractory oxides SnO2 or Cr2O3-MgO spinel or perovskite or metalloid carbides or metals can be used at very high temperatures.

[0316] Preferably, the conductor is made of a precious metal, preferably selected from platinum, gold, palladium, rhodium, and iridium.

[0317] Within the ambient temperature range (preferably between 20°C and 1000°C), the resistivity of the first conductor and the second conductor is preferably less than 10 ohm·m.

[0318] According to the first embodiment, each conductor is formed of a cable, which is formed of one or more wires. The first conductor and the second conductor are non-coaxial and are kept apart from each other by a dielectric isolator, the resistivity of which is preferably 10, 50, 100, or 1000 times or more the resistivity of the conductor.

[0319] According to a second preferred embodiment, the waveguide is formed of a coaxial cable, such as a coaxial cable with a BNC connector, comprising an inner conductor or sleeve forming a first conductor and an outer sleeve forming a second conductor, the two sleeves being separated by an electrically insulating intermediate sleeve. Preferably, the intermediate sleeve is made of an oxide of at least one element selected from Al, Zr, Mg, Ca, Ti, and Si, and more preferably is composed of an oxide of at least one element selected from Al, Zr, Mg, Ca, Ti, and Si.

[0320] In one embodiment, the waveguide is formed of at least two linear conductors, preferably platinum cables, such as FKS platinum cables supplied by Ogussa, which are placed parallel to each other and spaced apart by a distance greater than 1 mm, preferably greater than 2 mm, and / or preferably less than 20 mm. Refractory pads, preferably alumina pads, are threaded onto the conductors, preferably through a first through-hole and a second through-hole through which the first and second conductors pass.

[0321] The length of the waveguide and preferably the length of the measuring component are preferably greater than 1m, preferably greater than 2m, preferably greater than 3m, or even greater than 10m, and / or less than 30m, or even less than 20m.

[0322] The two conductors are preferably parallel, except in the region of discontinuity. Local defects may form in parallel structures, resulting in discontinuities, particularly at the base.

[0323] Protective coating

[0324] Preferably, particularly before being fixed to or integrated into a carrier (preferably in the form of a plate), the waveguide and / or each conductor can be inserted into a protective cladding, which may optionally be segmented, to protect the conductor from heat and / or corrosion and / or chemical erosion.

[0325] The protective coating can be made of ceramics, especially alumina, particularly for environments with temperatures above 400°C.

[0326] The protective coating is preferably made of a material whose coefficient of thermal expansion is substantially the same as that of the conductor.

[0327] Preferably, the thermal expansion coefficient of the waveguide, preferably at least the thermal expansion coefficient of the measuring component, is substantially the same as the thermal expansion coefficient of the portion of the object that houses the measuring component (+ / -20%, preferably + / -10%).

[0328] The protective coating can be straight or curved and extends around the measuring component. This coating can be used to give the measuring component or even the transmission component a curved shape.

[0329] Carrier

[0330] Waveguides, especially at least the measuring components, can also be fixed to carrier 40 (see...). Figure 10 or Figure 2 Preferably, the carrier is in the form of a plate, and the carrier itself is in contact with the object 30.

[0331] A given carrier, especially a carrier in the form of a plate, can carry multiple measurement components, or even all the measurement components of a waveguide array.

[0332] The carrier is preferably made at least in part of a material formed by filaments and / or fibers bonded together by a ceramic matrix (to form a so-called "ceramic matrix composite").

[0333] The choice of fibers and / or filaments and ceramic matrix will depend on the environment in which the ceramic matrix composite must be placed, particularly on conditions of temperature, corrosion, thermal cycling and expansion, as well as on the nature of the object to be monitored.

[0334] The coefficient of thermal expansion of ceramic matrix composites can be adjusted using techniques known to those skilled in the art, particularly by adjusting the composition of the ceramic matrix composite.

[0335] Preferably, as measured using the three-point loading geometry specified in ASTM C1341-13, the yield strength of the ceramic matrix composite is greater than 3 MPa, preferably greater than 6 MPa, and most preferably greater than 10 MPa. Advantageously, this improves its mechanical strength, particularly its impact strength.

[0336] For example, the stacking of textiles or webs of fibers or filaments is well-suited for simple boards, the winding of filaments is well-suited for boards with rotational geometry, and the placement of filaments is well-suited for complex shapes in large dimensions.

[0337] Carriers are particularly useful when the object belongs to or forms the sidewall of the furnace.

[0338] The layout chosen for the fibers or filaments depends on the desired shape of the ceramic matrix composite and the ease with which the conductors must be attached to or inserted into the ceramic matrix composite. The ceramic matrix composite preferably has a crush resistance greater than 5 MPa, more preferably greater than 10 MPa, and / or a thermal conductivity greater than 2.0 W / m² between 20°C and 500°C. -1 .K -1 .

[0339] Preferably, the ceramic matrix composite material comprises one or more of the following oxides by weight percentage: Al2O3, ZrO2, HfO2, Cr2O3, MgO, CaO, and SiO2.

[0340] In one embodiment, the ceramic matrix composite material has the following chemical composition in weight percentage of oxides, such that Al2O3 + SiO2 > 80%, preferably greater than 85%, preferably greater than 90%, or even greater than 95%.

[0341] In one embodiment, the matrix comprises, and preferably consists of, one or more compounds selected from the group consisting of Al2O3, ZrO2, Cr2O3, MgO, CaO and SiO2, in terms of greater than 80%, greater than 90%, greater than 95%, and preferably substantially 100% by weight thereof.

[0342] Preferably, the volume of the fibers or filaments accounts for more than 25%, more than 30%, more than 40%, more than 50%, more than 60%, and / or less than 70% of the volume of the CMC material, ignoring its porosity, and the filler required to reach 100% is formed from a ceramic matrix that bonds the fibers together. The diameter of the fibers, i.e., the average diameter measured along the midpoint of all fibers, is preferably between 3 micrometers and 30 micrometers, and more preferably between 5 micrometers and 25 micrometers.

[0343] Preferably, the carrier is in the form of a (planar or non-planar) plate and has a preferably constant average thickness between its main surfaces, the average thickness being preferably less than 40 mm, preferably less than 32 mm, preferably less than 28 mm, preferably less than 22 mm, preferably less than 20 mm, or even less than 18 mm, 15 mm, or 10 mm, and / or preferably greater than 1 mm, preferably greater than 2 mm, or even greater than 3 mm, or greater than 5 mm.

[0344] The surface area of ​​the main surface of the carrier is preferably greater than 100 cm². 2 Preferably, it is greater than 200cm 2 Preferably, it is greater than 300cm 2 Preferably greater than 400cm 2 and / or less than 20000cm 2 Preferably less than 15000cm 2 or even less than 10000cm 2 .

[0345] In one embodiment, the carrier is in the form of a roll before being mounted against the object. In another embodiment, the carrier is secured to the cold surface of the object, and preferably, the carrier includes a perforated area, i.e., an area through which multiple orifices pass to facilitate heat exchange with the cold surface.

[0346] The object can be specifically a first layer formed of dense, fused, or sintered bricks.

[0347] In one embodiment, the carrier is bonded to the cold surface of the object. Preferably, the adhesive used to fix the waveguide to the carrier and / or the carrier to the object is selected from a mixture of ceramic powder and adhesive, which is preferably applied in liquid form.

[0348] Preferably, the powder is alumina and / or silica and / or mullite powder. Preferably, the adhesive is selected from colloidal silica, sodium silicate, organic resins, organic adhesives, and mixtures thereof. The adhesive used may also be a commercial adhesive, such as Fixwool Adhesive FX from Unifrax.

[0349] In one embodiment, the waveguide's measurement component is embedded in a ceramic matrix composite material or a precursor of the ceramic matrix composite material, and preferably sandwiched between two fabrics of the composite material.

[0350] According to a first specific embodiment, the waveguide's measurement components are fixed to a carrier by means of an interface layer. The interface layer may be an adhesive comprising a thermosetting, thermoplastic, or elastomeric polymer, particularly when the temperature of the surface of the object containing the carrier (especially the cold surface) is less than or equal to 400°C.

[0351] In one embodiment, the waveguide's measurement components are fixed to a carrier by means of refractory filaments, nails, or strips.

[0352] exist Figure 11 In one embodiment shown, the first and second conductors of the measuring component are integrated into a filament arrangement of a ceramic matrix composite material or a filament arrangement of a precursor of the ceramic matrix composite material, for example, as weft filaments, warp filaments, or knitted filaments. The first and second conductors are substantially parallel and separated by a predetermined distance. Preferably, the distance separating the conductors is greater than 0.3 mm, preferably greater than 0.4 mm, preferably greater than 0.5 mm, and less than 30 mm, preferably less than 10 mm, preferably less than 5 mm, and preferably less than 3 mm.

[0353] To maintain the distance between the two conductors, at least one or more filaments made of dielectric material can be inserted between the first and second conductors of the waveguide. In one embodiment, a given carrier can support multiple measurement components of various waveguides.

[0354] In one embodiment, the measuring component is housed in a ceramic protective coating incorporated into the carrier during carrier manufacturing, or in a channel formed in the carrier during or after carrier manufacturing.

[0355] Spacer

[0356] Regardless of the implementation method, direct electrical contact between the two conductors can be avoided by inserting a dielectric insulator 25 or "spacer", which is made of, for example, mica, mica derivatives, titanium, barium, mullite, cordierite or alumina.

[0357] The dielectric insulating element can be a single piece or an assembly of multiple dielectric pads. Preferably, the dielectric pads are inserted between conductors, and the pads are preferably in the form of beads inserted through at least one conductor, and preferably two conductors.

[0358] The pad will be described in more detail in the remainder of the instruction manual.

[0359] The predetermined distance between the two electrical conductors is preferably substantially constant.

[0360] When the first and second conductors are integrated into a fabric of ceramic matrix composite material and form constituent filaments of the fabric (e.g., weft or warp filaments), the spacer can be formed from filaments made of a dielectric material, which can also be part of the fabric composition. For example, if the first and second conductors are weft or warp filaments, they can be formed from one or more other weft or warp filaments, respectively, made of a dielectric material. Figure 11 The fine filaments in the middle are separated by 25).

[0361] Discontinuity

[0362] The number of discontinuities per meter of waveguide measurement component, particularly the number of basic discontinuities, is preferably greater than 10, greater than 15, greater than 20, greater than 30, greater than 40, or greater than 50, and / or less than 10,000, less than 1,000, less than 500, or less than 100. Therefore, it is advantageous to assess the nature of the environment surrounding the measurement component with good accuracy over substantially the entire length of the component.

[0363] Preferably, the distance between any two consecutive discontinuities 24 along waveguide 12, particularly the distance between any two consecutive base discontinuities, is less than 1 / 100 of the wavelength of the interrogation signal (the wavelength of the interrogation signal is equal to the propagation speed of the interrogation signal (approximately 200,000 km / s for electromagnetic waves) divided by the frequency of the highest peak in the spectrum of the interrogation signal).

[0364] The distance is preferably greater than 10mm, 15mm or 20mm, and / or less than 100mm or 50mm.

[0365] This effectively improves the sensitivity of messages transmitted by the interrogator.

[0366] Using discontinuities that reflect small changes in potential avoids the need for generating large discontinuities, which would easily and strongly attenuate the interrogation signal and thus hinder the monitoring of the entire length of the waveguide's measurement components. Preferably, discontinuities greater than 50%, preferably greater than 80%, and preferably greater than 90% reflect the base secondary echo and / or noise secondary echo, and preferably reflect the base secondary echo.

[0367] Utilizing these small, random potential variations contradicts the development of electroreflection measurement methods because these variations are considered harmful. Preferably, discontinuities are randomly added to the waveguide.

[0368] The discontinuities are variable, meaning that they do not all reflect the same echo when they receive the same interrogation signal. More preferably, the variation of the discontinuities, particularly the variation of the fundamental discontinuities, is random.

[0369] Discontinuities 24, particularly fundamental discontinuities, can be obtained by altering the surface of one or two conductors and / or dielectric insulators and / or the materials that manufacture them, for example by abrasion or chemical etching, or by adding dopants to the material, or by adding pads to alter the surface.

[0370] In one embodiment, the waveguide is formed of a coaxial cable, such as a coaxial cable with a BNC connector, comprising a conductor forming a first conductor and an outer sleeve forming a second conductor, the two sleeves being separated by a spacer in the form of an electrically insulating intermediate sleeve. Discontinuities 24, particularly basic discontinuities, can be created by varying the surface finish of the insulating sleeve, for example by creating roughness. Another approach includes creating random discontinuities on the outer sleeve, particularly basic discontinuities, for example by abrasion (without interrupting electrical conduction within the outer sleeve).

[0371] In one embodiment, some discontinuities, particularly basic discontinuities, are irregularities on the surface of the spacer, preferably formed facing the conductor, and preferably formed in at least one region of the spacer in contact with the conductor. Advantageously, texturing said regions allows for the generation of random discontinuities.

[0372] Discontinuities 24 can also be created by altering the surface finish (texturing) of the dielectric barrier 25, for example by generating roughness, such as by wear, particularly basic discontinuities, which are preferably random.

[0373] Preferably, texturing includes generating bumps with a height greater than 0.05 mm, preferably greater than 0.1 mm, preferably greater than 0.2 mm, preferably greater than 0.4 mm, preferably greater than 0.5 mm, or even greater than 0.8 mm, and / or less than 3 mm, less than 2 mm, or less than 1 mm.

[0374] The density of the raised bumps, i.e., the number of raised bumps per unit area of ​​texturing (particularly the unit area of ​​the surface of the dielectric material and / or the unit area of ​​the surface of at least one of the first and second electrical conductors), is preferably greater than 1 / 10000mm. 2 Preferably, more than 1 per 1000mm 2 Preferably, the number is greater than 0.5 per 100mm. 2 (or 0.5 per cm) 2 ), and / or less than 10 / mm 2 Preferably less than 1 per mm 2 Or preferably less than 1 per 10 mm 2 (or 10 per cm) 2 ).

[0375] The predetermined distance between the two electrical conductors is preferably substantially constant. The two conductors are preferably parallel, except in regions of discontinuity. Local defects may form in the parallel structure, resulting in discontinuities, particularly at fundamental discontinuities.

[0376] Preferably, the basic discontinuity points are generated by changing the following distances:

[0377] - The distance between two electrical conductors, or

[0378] - The distance between the first and / or second electrical conductors on one side and the dielectric material of the carrier on the other side, the distance varying by more than 0.1 mm within the length range of the measuring component, which is less than 2 mm, preferably less than 1 mm.

[0379] Preferably, in order to create discontinuities, the dielectric pad is arranged to contact the first conductor and the second conductor.

[0380] Dielectric pads, especially pad beads, can have lengths greater than 10 mm, 15 mm, or 20 mm, and / or less than 100 mm or 50 mm, as measured along the waveguide.

[0381] Dielectric pads, particularly pad beads, preferably have a width greater than 1 mm, 2 mm or 3 mm and / or less than 10 mm or 5 mm, i.e., the maximum dimension in a plane transverse to its length direction.

[0382] Figure 3 Various possible implementations of the dielectric pad are shown. In particular, Figure 3 The following implementation is shown, wherein:

[0383] - The spacer bead 23 is passed through only one of the first conductor and the second conductor (3E) or both of the first conductor and the second conductor (3A to 3D);

[0384] - Pad beads 23 are inserted to form a protective coating 27, which is segmented (3A, 3C to 3E) or unsegmented (3B) between the two first conductors and the second conductor (3A to 3D) to protect one (3E) or both conductors;

[0385] - Insert pad beads 23 with the same shape (3A, 3D) or different shapes (3B, 3C, 3E);

[0386] - Pad beads 23 with surfaces textured in the same way (3A to 3C, 3E) or not in the same way (3D);

[0387] - One or more conductors are symmetrical (3A, 3B, 3C, 3D) or asymmetrical (3E) with respect to the axis of each pad bead 23;

[0388] - One or more conductors are parallel to (3A-3E) or not parallel to the axis of each pad bead 23.

[0389] The pad is also helpful in identifying the region where the fundamental secondary echo is generated, and therefore can be used as an identification marker.

[0390] Preferably, in order to create basic discontinuities, the composition and / or structure of the carrier can be altered near or around the first and second conductors, or between the first and second conductors. Specifically, the composition and / or structure of the carrier can vary by more than 10% over a length of measuring component less than 1 mm. For example, the carrier structure can be locally deformed to create depressions or bulges, for example by mechanical means or by local melting, and / or the composition of the carrier can be altered.

[0391] The carrier can be a carrier fixed to the waveguide, such as a carrier made of CMC.

[0392] For example, a waveguide can be fixed to a carrier that is not of uniform material mass, but contains variations due to the presence of holes (through holes or isolation holes / blind holes), which may originate, for example, from textile fabric contained within the carrier. The irregular continuity of the filaments creates random fundamental discontinuities.

[0393] For example, waveguides are fixed to or embedded in a carrier that includes inclusions, and each inclusion (e.g., in the form of particles or fibers) positioned along the measuring component causes a change in the composition of the carrier.

[0394] Random distribution of discontinuities

[0395] Preferably, the discontinuities are irregularly distributed along the waveguide. More preferably, the discontinuities, especially the fundamental discontinuities, are randomly distributed along the waveguide.

[0396] The random nature of the distribution or amplitude of discontinuities advantageously avoids the risk of the accumulation of secondary echoes in the same time period, which could strongly weaken the interrogation signal.

[0397] Dielectric pads can have the same or different shapes and / or sizes and / or be made of the same or different materials. Even if dielectric pads look the same, no two pads are exactly the same.

[0398] Variations in the shape and composition of the pads, particularly the shape and composition of the pad beads, and the position of the pad beads relative to the conductor, allow for the generation of randomized discontinuities. Therefore, fundamental discontinuities can be generated randomly.

[0399] To generate random discontinuities, particularly fundamental discontinuities, in embodiments where the first and second conductors of the measuring component (e.g., as weft filaments, warp filaments, or knitted filaments) are integrated into a filament arrangement on a carrier made of a ceramic matrix composite material, the first and second conductors and / or other filaments (or non-conductive filaments) made of a dielectric material can be randomly altered, for example, by abrasion or chemical etching. The filaments made of the dielectric material can also, or alternatively, be randomly wound around the first and / or second conductors. The filaments and / or fibers and / or particles made of the dielectric material can also, or alternatively, be randomly added to the fabric. In addition to or as an alternative to the other possibilities described above, particles of variable size or shape, or particles with uneven placement, can be brought into contact with the fabric prior to impregnation. Choices made regarding the size or shape of the particles, the applied texture, or the length of the fibers allow for the generation of random discontinuities.

[0400] Before impregnating with a matrix precursor and subsequently curing to form an instrumented carrier, the conductor can also, or alternatively, be arranged to contact an irregularly textured textile or a felt of randomly arranged fibers.

[0401] Conditions for Rayleigh scattering

[0402] The waveguide preferably satisfies the Rayleigh scattering condition. Advantageously, the region with the fundamental secondary echo that is reflected can be easily located.

[0403] Preferably, the basic discontinuities 24 are spaced apart by a distance measured along the waveguide, which is at least 10 times, preferably at least 15 times, and preferably at least 20 times the reference wavelength. The reference wavelength is equal to the propagation speed of the interrogation signal (approximately 200,000 km / s for electromagnetic waves) divided by the frequency of the highest peak in the spectrum of the interrogation signal.

[0404] This distance can be specifically defined by the length of the dielectric pad, particularly the length of the pad beads threaded onto the waveguide. To generate a sufficient fundamental second echo, the length of the pad is preferably configured according to the reference frequency (the reciprocal of the reference wavelength) to satisfy the Rayleigh scattering conditions.

[0405] For example, for a reference wavelength of about 15 cm, pads (e.g., pad beads) with a length of less than 3 cm, preferably less than 2 cm or 1 cm, are very suitable. For example, for an interrogation signal with a frequency of 1 GHz, alumina pad beads with a length of less than 10 mm threaded on a platinum wire produce a low-amplitude secondary echo, while pad beads with a length greater than 100 mm produce a hard secondary echo.

[0406] In the case of basic discontinuities and under Rayleigh scattering conditions, accurate measurements can be performed over lengths greater than 1m, preferably greater than 2m, preferably greater than 5m, preferably greater than 10m, greater than 15m, or greater than 20m, and / or less than 500m, for example, over the entire length of the measuring component.

[0407] Waveguide array

[0408] Preferably, the array comprises a plurality of measuring elements, which are preferably parallel to each other and parallel to the thermal surface of the object, such that the density of discontinuities over the equipped area, preferably the density of basic discontinuities, is: per m 2 The hot surface area has more than 3, preferably more than 10, preferably more than 50, preferably more than 100, preferably more than 500, preferably more than 800 discontinuities, and / or less than 1,000,000, preferably less than 500,000, preferably less than 100,000, preferably less than 50,000, preferably less than 10,000, preferably less than 5,000, preferably less than 2,000 discontinuities. This improves the reliability of the analysis performed by the interrogator.

[0409] Preferably, the measuring components are formed in a mesh extending on a curved or flat surface (preferably a flat surface), and each waveguide is preferably connected to its own interrogator.

[0410] The waveguide array may include more than one, more than two, preferably more than three, and more preferably more than five of the meshes, which are preferably parallel to each other and preferably regularly spaced apart from each other in a direction perpendicular to the surface of the component.

[0411] exist Figure 4 The image shows two meshes 32 and 34, which in this case are used to equip the furnace bottom 41.

[0412] In one implementation, at least two waveguides intersect at different depths, measured perpendicular to the hot surface. Since the characteristics of the stacked waveguides are known, it is advantageous to define the temperature distribution along the depth direction, and / or the degree of thickness reduction of the object being evaluated (e.g., the bottom of a furnace) at each point below the hot surface where multiple waveguides are stacked. For this purpose, a central computer can collect messages from the individual interrogators and, since the spatial distribution of the waveguides is known, infer the wear distribution from them.

[0413] Inquirer

[0414] The input terminal of the waveguide's electrical conductor is electrically connected to interrogator 18, or "reflectometer". The interrogator is configured as follows:

[0415] - An interrogation signal is injected by generating a change in potential difference between the two conductors of the waveguide; and

[0416] - Analyze the response signal reflected in response to the interrogation signal.

[0417] Interrogator 18 typically includes transceiver 21 and control module 31. Figure 2 The control module 31 typically includes a processor and memory, in which a computer program is loaded. With the aid of this computer program, the processor can control the transmission of interrogation signals and analyze received reflected signals to identify echoes reflected from discontinuities. In one embodiment, the analysis is performed by an analysis computer 39 that communicates with the interrogator.

[0418] An interrogator can be, for example, a voltage generator coupled to an oscilloscope, allowing the reception and analysis of reflected signals. An interrogator can also be a network analyzer equipped with software such as "VNA software" to generate interrogation signals and analyze reflected signals.

[0419] In a preferred embodiment, such as Figure 4 As shown, the first interrogator 181 is connected to the input terminal of the waveguide. The second interrogator 182 is connected to the output terminal of the waveguide.

[0420] Therefore, the second interrogator receives the portion of the interrogation signal injected by the first interrogator that is not reflected by the respective discontinuities of the waveguide. Preferably, the second interrogator can also transmit the interrogation signal. The presence of two interrogators advantageously allows information about each side of the fracture region to be obtained in the event of a waveguide break. This thus improves the robustness of the device.

[0421] Analysis

[0422] The analysis performed by the interrogator is based on electrical time-domain reflectometry (E-TDR) or electrical frequency-domain reflectometry (E-FDR), which are conventional techniques for measuring changes in the state of a medium through a waveguide and an interrogator.

[0423] Each interrogation signal, preferably in the form of a pulse or "Dirac," is formed by generating a change in potential difference between two conductors of the waveguide. The latter returns a response signal, which is then analyzed to derive information about the medium through which the pulse passed. In the presence of impedance discontinuities, for example, significant physicochemical changes in the medium causing local impedance variations, a portion of the interrogation signal is reflected back to the interrogator, allowing for the identification and analysis of this change.

[0424] The interrogation signal can take the form of any type of periodic wave. The interrogation signal can be repeated. Preferably, the maximum amplitude of the interrogation signal is between 0.1V and 100V, and preferably less than 10V, and even more preferably less than 1V. The frequency of the highest peak in the spectrum of the interrogation signal is preferably greater than 10kHz, preferably greater than 100kHz, preferably greater than 1MHz, preferably greater than 100MHz, preferably greater than 200MHz, preferably greater than 500MHz, preferably greater than 1GHz, and / or less than 50GHz, preferably less than 30GHz, preferably less than 20GHz, preferably less than 10GHz, preferably less than 6GHz, and preferably less than 4GHz. The interrogation signal can be transmitted in the form of a signal train, which preferably comprises a series of periodic signals whose frequencies vary depending on the periodic signal in question.

[0425] The frequency of the interrogation signal is typically customized based on the length of the measuring component. The wavelength of the interrogation signal is typically shorter than the length of the waveguide's measuring component. The ratio of the wavelength of the interrogation signal to the length of the waveguide's measuring component is preferably 0.1 to 0.9, more preferably 0.1 to 0.5, and even more preferably 0.1 to 0.3.

[0426] Preferably, the length of the waveguide's measuring component is not a multiple of the wavelength of the interrogation signal to avoid resonance problems.

[0427] For example, for measurements at 600°C or higher, for waveguides with a length between 10m and 15m, the frequency of the interrogation signal could be 1GHz (corresponding to a wavelength of approximately 20cm).

[0428] Each interrogation signal propagates through a waveguide to the free end of the conductor. At each discontinuity, a portion of the interrogation signal, the "echo," is reflected back to the interrogator. All reflected echoes together form a response signal associated with the interrogation signal, which the interrogator analyzes.

[0429] Specifically, the transmitted echo reflected from the input end of the waveguide, the terminal echo reflected from the output end of the waveguide, and a set of discontinuity echoes reflected from the discontinuities of the waveguide are different from each other. The discontinuity echoes have lower amplitudes and exhibit various amplitudes and shapes.

[0430] The interrogator is programmed to analyze the reflected signals and, if possible, compare these reflected signals to determine information relating to the state of an object in the region of the waveguide's measurement component, and preferably to transmit messages accordingly.

[0431] Any technique can be implemented for analyzing the response signal used in the electrical time domain or frequency domain reflectometry, and in particular the technique described in Baokai Chen et al.’s article “Distributed temperature sensing with unmodified coaxial cable based on random reflections in TDR Signal” in 2019 Meas. Sci. Technol. 30.015105 or in Aurimas Dominauskas et al.’s article “Electric time domain reflectometry distributed flow sensor” in the journal Composites Part A 38 (2007) 138-146.

[0432] Preferably, the message includes:

[0433] - Values ​​representing the physical state of the object, particularly the remaining thickness or average temperature and / or values ​​representing temperature deviations along the measuring section; and / or

[0434] - The value is a change from the previous situation; and / or

[0435] - The location of defects or damage that affect the physical state of the object.

[0436] Messages can be sent to a central computer and / or presented to the operator, for example, on a screen and / or by turning on lights and / or by sending auditory signals.

[0437] In a preferred embodiment, at least a portion of the waveguide is capable of transmitting a quantitative indication in its returned response signal about the temperature experienced due to wear of the object. As the thickness of the object portion, such as the bottom of a furnace, decreases, the frequency of the response signal returned by the waveguide changes. This change advantageously allows for the determination of local temperature variations. Advantageously, therefore, anomalous changes in the waveguide's temperature can be detected, and intervention can be made to repair the object, such as replacing the refractory lining.

[0438] Object

[0439] Object 30 can be all or part of a glass-making furnace containing a hot surface, particularly the sidewalls or bottom of the furnace, or bricks or a group of bricks belonging to the sidewalls or bottom of the furnace. Objects can also be, for example, bricks of a feeder, upper structural components (gap bricks, top bricks, etc.), forming components (lips, etc.), or throat bricks.

[0440] The object may include the back layer, and for example, the side wall or bottom of the furnace.

[0441] The use of waveguides advantageously allows exposure to high temperatures, such as above 100°C, above 125°C, above 200°C, or above 300°C. For example, metal waveguide cladding with a sacrificial polymer coating allows monitoring in environments up to 300°C.

[0442] Manufacture or installation

[0443] Various techniques can be used to mount waveguides, particularly in the back layer of an object. Preferably, the waveguide is placed in a hot region of the furnace where the temperature is above 400°C, preferably above 500°C, preferably above 600°C, and below 1300°C, preferably below 1200°C, more preferably below 1100°C.

[0444] According to a preferred embodiment, at least a portion, and preferably all, of the measurement components of each waveguide is covered by a sacrificial cladding.

[0445] Each measuring element is arranged in an aperture (which is formed, for example, in the backing layer) or, for example, in a groove formed in the backing layer. A refractory initial material mixture, preferably concrete, having substantially the same composition as the backing layer, is deposited in the aperture or groove to cover the sacrificial cladding of the waveguide.

[0446] The initial raw material is then solidified, preferably sintered, and preferably solidified during furnace heating. The sacrificial coating is typically removed by heat treatment, preferably during sintering or heating, and preferably by applying a temperature between 400°C and 1200°C.

[0447] In addition to or as an alternative to sacrificial coatings, sacrificial filler materials (such as resins) can be used to fill the remaining portion of the orifice or recess.

[0448] This method advantageously allows for close contact between the waveguide and the object, which enables good heat exchange and limits the risk of molten glass intrusion, while also limiting the stress applied to the waveguide.

[0449] First embodiment: furnace bottom

[0450] The object can be the bottom of the furnace according to the present invention.

[0451] exist Figure 4 In the embodiment shown, the bottom has a generally rectangular shape when viewed from above.

[0452] like Figure 5As shown, the bottom typically includes: a first layer of refractory bricks 241 stacked in the form of plates, in contact with the molten glass; two concrete layers 242a and 242b; and two insulating layers 243a and 243b. All these layers are laterally defined by bricks 244 (referred to as "edgestone" bricks) and rest on a foundation 245.

[0453] Arrow D indicates the flow direction of the molten glass.

[0454] Refractory brick 241 can have various shapes, such as rectangular parallelepiped shapes.

[0455] Refractory brick 241 is preferably made of a material resistant to contact with glass at temperatures above 600°C, or even above 1000°C, or practically above 1200°C. More than 90% by weight of the refractory brick may consist of one or more oxides selected from the group consisting of ZrO2, Al2O3, SiO2, Cr2O3, Y2O3, and CeO2. The refractory brick preferably contains more than 90% ZrO2, Al2O3, and SiO2.

[0456] In one embodiment, the brick contains more than 15% ZrO2, preferably 26% to 95% ZrO2. The refractory brick composition typically comprises more than 90%, preferably more than 95%, of the following: 26% to 40% ZrO2; 40% to 60% Al2O3; and 5% to 35% SiO2. The glassy phase comprises about 5% to 50%, and preferably 10% to 40%. Preferably, the glassy phase is a silicate-based phase, wherein the weight percentage of Na2O is less than 20%, preferably less than 10%, and / or wherein the weight percentage of Al2O3 is less than 30%. All percentages are typically provided by weight of oxides. Preferably, the oxides comprise more than 90%, preferably more than 95%, and preferably more than 98% of the weight of the refractory brick.

[0457] Concrete layers 242a and 242b are, for example, from the ERSOL series sold by SEFPRO. They are typically formed by casting in a checkerboard mold that is offset relative to the mold of the first upper layer (the layer closest to the glass) to increase thermomechanical resistance and reduce the risk of infiltration when molten glass penetrates.

[0458] The upper insulating layer 243a can be formed by precast refractory concrete paving (usually from the ERMOLD series supplied by SEFPRO).

[0459] The lower insulating layer 243b can be made of fiber insulating material.

[0460] exist Figure 6In the first configuration shown, waveguides 12 are arranged perpendicular to the flow direction D of the molten glass, and each waveguide 12 is preferably surrounded by a sacrificial cladding made of a polymer (e.g., PET or PE). The waveguides are placed on the upper insulating layer 243a. The waveguides may optionally be fixed in place using a temporary adhesive, which may decompose during the heating of the furnace. Concrete forming the lower insulating layer 242b is poured onto and covers the waveguides.

[0461] The waveguide is exposed outside the furnace through an aperture, which is formed, for example, through the edging brick.

[0462] In one embodiment, the alumina protective coating 27 at least partially surrounds at least one waveguide to protect at least one waveguide and facilitate its replacement.

[0463] Waveguide 12 is connected to at least one interrogator 18, which is electrically connected to the input terminal 12e of each waveguide via a transmission component 15. The interrogator 18 is configured to inject an interrogation signal through said terminal and receive a response signal through the waveguide in response to the injection. The interrogator communicates with an analysis computer 39, for example, via Wi-Fi or via cable. The analysis computer 39 preferably has memory and runs software or programs configured to correlate the response signals received from the waveguides with the state of an object.

[0464] In a possible second construction (its layout is as follows) Figure 7 (Shown schematically in [image], and which can be combined with schematic illustrations in previous images), the waveguide 12, preferably surrounded by a sacrificial polymer coating, is arranged parallel to the flow direction D of the molten glass. The waveguide 12 is placed on the upper insulating layer 243a. Optionally, the waveguide 12 is secured in place using a temporary adhesive, which may decompose during furnace heating. Concrete forming layer 242b is poured onto and covers the waveguide.

[0465] Preferably, the waveguide array is arranged at the bottom, and this array preferably takes the form of multiple parallel and / or vertical waveguides, for example, in the form of two assemblies, with their measuring components oriented at right angles when viewed from above. Figure 3 As shown.

[0466] The waveguide is placed in a hot region at the bottom, typically between 800°C and 1100°C.

[0467] In one implementation, all waveguides are located in the same plane. Alternatively, the waveguides can be arranged at various depths in the bottom.

[0468] Embodiment: top

[0469] The above rules apply to the top.

[0470] like Figure 8 As shown, the top includes dense bricks 241 forming the arch base 241-1 and arch stones 241-2 of the top 28, which are typically covered with a backing layer consisting of a concrete barrier layer 242 and an insulating layer 243. According to one possible embodiment, the measuring component is preferably placed on the cold surface of the dense bricks 241 within the concrete barrier layer 242.

[0471] Embodiment: furnace side wall

[0472] The above provisions may also be applied when the object is all or part of the side wall of the furnace.

[0473] like Figure 10 As shown, the sidewalls of the furnace include dense bricks 241 in contact with the molten glass, and optionally a backing layer formed of porous refractory bricks. Waveguide 12, particularly the measuring component at least within the waveguide, can be fixed to a plate-like carrier 40 (see...). Figure 10 The plate-shaped carrier 40 itself is in contact with the brick 241. As described above, the carrier is preferably made at least partially of a ceramic matrix composite material.

[0474] As should now be clear, the present invention provides a solution that allows for more accurate and real-time assessment of the remaining thickness or temperature of an object in a glass-making furnace.

[0475] Of course, the present invention is not limited to the embodiments described and shown, which are provided for illustrative purposes only.

[0476] In particular, the examples of the objects described above are not exclusive.

Claims

1. A glass manufacturing furnace, comprising: - Glass melting chamber (11; 16), which has a hot surface (37) exposed to the interior of the chamber; - A device for monitoring the state of a component of the furnace referred to as an "object" (30) by means of electrical time-domain or frequency-domain reflectometry, the device comprising: - An array of at least one filamentary waveguide, preferably an array of multiple filamentary electromagnetic waveguides (12), each waveguide comprising first and second electrically isolated electrical conductors (121, 122) between an input and an output. - An interrogator (18), electrically connected to the input (12e), is configured to inject an interrogation signal through the input, receive a response signal reflected by the waveguide in response to the injection, analyze the response signal, and send a message about the state of the object based on the analysis. The waveguide includes a measurement component (14) located between the input and output ends of the waveguide, the measurement component (14) extending parallel to the hot surface (37) and located at a depth greater than 10 cm. The measuring component (14) includes at least a plurality of discontinuities randomly distributed along the waveguide, which are referred to as "basic discontinuities" (24). The waveguide has more than 10 basic discontinuities per meter of the measuring component. The fundamental discontinuity points: - Capable of generating echoes with an amplitude greater than 0.5%, preferably greater than 1%, of the amplitude of the terminal echo reflected from the output end of the waveguide in response to the injection of the interrogation signal; these echoes are referred to as "fundamental secondary echoes," and / or - Formed from the following: - A raised surface created by texturing the outer surface of the waveguide, and / or the dielectric material interposed between the first and second electrical conductors, and / or at least one of the first and second electrical conductors, and / or - Unevenness caused by irregular segments of the dielectric material inserted between the first and second electrical conductors, and / or - Local variations in the distance between the first and second electrical conductors; and / or - The variation in the distance between the first and / or second electrical conductors and the dielectric material of the carrier, preferably made of a ceramic matrix composite material, on the one hand, and / or on the other hand. - Changes in the structure and / or composition of the environment surrounding or between the first and second electrical conductors.

2. The furnace according to the preceding claim, wherein, The fundamental discontinuity points are: - A raised surface created by texturing the outer surface of the waveguide, and / or the dielectric material interposed between the first and second electrical conductors, and / or at least one of the first and second electrical conductors, and / or - Unevenness caused by irregular segments of the dielectric material inserted between the first and second electrical conductors; and / or - Local variation in the distance between the first and second electrical conductors.

3. The furnace according to any one of the preceding claims, wherein, The height of the raised bump is greater than 0.05mm, preferably greater than 0.1mm, preferably greater than 0.2mm, preferably greater than 0.4mm, preferably greater than 0.5mm, or even greater than 0.8mm, and less than 3mm, less than 2mm, or less than 1mm.

4. The furnace according to any one of the preceding claims includes a pad (23) in the form of a bead and made of a dielectric material, which is disposed in the measuring element on the first electrical conductor and / or the second electrical conductor.

5. The furnace according to the preceding claim, wherein, Multiple pads are arranged together to form a segmented protective cladding (27) extending over the entire length of the measurement component of the waveguide.

6. The furnace according to any one of the preceding two claims, wherein, The length of the pad is less than 10cm, preferably less than 5cm, preferably less than 3cm, more preferably less than 2cm, and greater than 0.5cm.

7. The furnace according to any one of the preceding claims, wherein, The waveguide satisfies the Rayleigh scattering condition.

8. The furnace according to any one of the preceding claims, wherein: a) The measurement element of each waveguide in the array is parallel to the hot surface and extends at a distance such that the measurement element is at a temperature greater than 500°C during use; b) The maximum distance between the two measurement components of any two waveguides in the array is greater than 20 cm; c) Each of the waveguides in the array is inserted into an aperture in the object, the aperture being configured to provide space for the thermal expansion of the waveguide; d) The equivalent diameter of the measurement element of each waveguide in the array is greater than 1 mm and less than 50 mm; e) The first and second electrical conductors of the measuring components of each waveguide in the array are separated by a distance greater than 0.3 mm and less than 30 mm; f) The measuring component has the following number of bends: - If the length of the measuring component is less than 3 meters, then the measuring component has less than 2 bends per meter of length; - If the length of the measuring component is greater than or equal to 3 meters, then there is less than 1 bend per meter.

9. The furnace according to any one of the preceding claims, wherein, The array of waveguides is at least partially, preferably entirely, located within or in a sublayer of the back layer, which is located behind a first layer formed by an assembly of bricks defining the thermal surface of the object.

10. The furnace according to any one of the preceding claims, wherein, The radius of curvature of the measurement element of each waveguide in the array is at least three times the equivalent diameter of the measurement element at each point.

11. The furnace according to any one of the preceding claims, wherein: - The material used to make the electrical conductor is a refractory metal or a precious metal, preferably selected from the group consisting of platinum, tungsten, gold, palladium, rhodium, ruthenium, iridium, or alloys of these elements, and / or - The first and second electrical conductors are separated by a dielectric material comprising an oxide of at least one element selected from Al, Zr, Mg, Ca, Ti, and Si, and / or - At least a portion of the measurement component of each waveguide in the array is protected by a ceramic cladding surrounding the measurement component.

12. The furnace according to any one of the preceding claims, wherein, In addition to the bending, at least some of the waveguide's measuring components are parallel to each other.

13. The furnace according to any one of the preceding claims, wherein, Each measuring component of the waveguide of the array extends into a housing formed in the object and defining space for the thermal expansion of the waveguide. The ratio of the equivalent diameter of the housing to the equivalent diameter of the measuring component is greater than 1.05 and less than 3, taking into account all cross-sections along the measuring component or the housing, the equivalent diameter of the measuring component or the housing is the largest of the cross-sectional diameters of the measuring component or the housing.

14. The furnace according to any one of the preceding claims, wherein, The first and second conductors are fixed to the carrier (40), which is preferably in the form of a plate made of ceramic matrix composite material, and the first and second conductors are integrated into the carrier (40) or fixed to the surface of the carrier (40).

15. The furnace according to any one of the preceding claims, wherein, At least one measuring element of a waveguide extends in a direction perpendicular to the flow direction of the molten glass.

16. The furnace according to any one of the preceding claims, wherein, The measuring component of the waveguide is located at a depth of less than 200 cm, measured from the hot surface.

17. The furnace according to any one of the preceding claims, wherein, The measuring element of each waveguide in the array is located at a distance such that the measuring element is at a temperature greater than 700°C and less than 1300°C during use.

18. The furnace according to any one of the preceding claims, wherein, The first and second conductors: - Fixed to the carrier (40), the carrier (40) being formed of a ceramic matrix composite material, preferably in the form of a plate, preferably fixed by an interface layer or by refractory filaments, nails or strips, or - It is integrated into a ceramic matrix composite material, preferably in the form of a plate.

19. The furnace according to any one of the preceding claims, wherein, The amplitude of the primary secondary echo is less than 30% of the amplitude of the terminal echo reflected from the output end of the waveguide.

20. A method for manufacturing a furnace according to any one of the preceding claims, wherein for at least one waveguide of the array, the method comprises the following sequential steps: 1) A sacrificial material is inserted between the measurement component of the waveguide and the object or the precursor of the object, and then... 2) If the sacrificial material has been inserted into the precursor of the object, the sacrificial material is removed after or during the manufacture of the object to create space for the thermal expansion of the measuring component.

21. The method according to the preceding claim, wherein: - The sacrificial material is the material that covers the sacrificial coating of the measuring component, and for inserting the sacrificial material: - Create the object around the measuring component, or - A housing in the form of a groove or hole is formed in the object or a precursor of the object, then the measuring component is inserted into the housing, and then the housing is filled with an unformed refractory product, preferably refractory concrete, the unformed refractory product comprising an adhesive, preferably cement, and capable of curing by activation of the adhesive, and then the unformed refractory product is cured; or - The sacrificial material is a filler material independent of the waveguide, and in order to insert the sacrificial material: - A housing in the form of a groove or hole is formed in the object or a precursor of the object. The measuring component is then inserted into the housing. The housing is then filled with the filler material to embed the measuring component. The amount of filler material is such that the expansion space is formed. The remaining portion of the housing is then filled with an unformed refractory product, preferably refractory concrete, which contains an adhesive, preferably cement, and is capable of curing by activation of the adhesive. The unformed refractory product is then cured.

22. The method according to any one of the preceding two claims, wherein: - In step 2), the sacrificial material is removed by heating at a temperature of 400°C to 1200°C during the heating of the furnace and / or during the sintering of the unformed refractory product or the object precursor.

23. A method for monitoring the state of an object in a glass manufacturing furnace according to any one of claims 1 to 19, the method comprising the steps of: a. To manufacture the glass manufacturing furnace; b. For each waveguide, control the interrogator connected to the waveguide such that the interrogator injects an interrogation signal through the input terminal of the waveguide; c. Analyze the response signal to determine information related to the state of the object in the region of the measurement component of the waveguide.

24. The method according to the preceding claim, wherein, The information relating to the state of the object is the remaining thickness of the refractory material or the temperature at one or more points on the object.

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