Method for monitoring the interior refractory lining of a container intended to contain molten materials.

Abstract

A system (100) for controlling / monitoring wear of the inner refractory lining (101) of a container containing molten materials, comprising at least one LiDAR device (103) orientable towards the refractory lining (101); an external structure (301) on which the LiDAR device (103) is mounted; the LiDAR device (103) comprising a laser source generating a pulsed laser beam (105); a rotary optical encoder which projects the laser beam (105) onto points (201) of a surface of the refractory lining (101); a receiver which receives the laser beam reflected on the plurality of points (201) of the surface of the refractory lining (102); and a controller which calculates a distance between the LiDAR device (103) and each of the plurality of points (201) of the surface of the refractory lining (101). Abstract figure: fig. 1

Description

Title of the invention: System for monitoring the interior refractory lining of a container intended to contain molten materials. Technical field

[0001] In general, the present invention relates to systems for controlling / monitoring the wear of the interior refractory lining of containers using LiDAR devices to measure said wear, preferably in the steel and metallurgy sectors. State of the art

[0002] Vessels or containers designed to contain materials at elevated temperatures, for example, at temperatures above the melting point of the material, are made of metal and are internally lined with a refractory material to protect the metal portion of the container from the high-temperature materials contained therein. However, due to the combined effects of oxidation, corrosion, and mechanical abrasion generated by the high-temperature materials, a portion of the refractory surface in contact with the molten material may gradually wear and deteriorate. For this reason, periodic inspections of the container must be carried out, as well as repairs to avoid catastrophic damage, such as rupture of the container. The inspections are also intended to avoid carrying out periodic repairs that may prove unnecessary.In addition, the costs associated with refractory lining repair are high. In addition, refractory lining repair involves stopping production processes (manufacturing downtime), which reduces the efficiency of manufacturing processes and increases costs.

[0003] Generally, the inspection of the condition of the refractory lining of the vessels is carried out visually by an experienced operator, looking for dark spots on the refractory lining indicating high rates of heat transfer to the refractory material and the vessel or the existence of significant wear in a particular area of ​​the lining. By means of said visual inspection, the operator can determine whether it is necessary to repair the lining. These manual techniques cannot be automated and systematized, require the stopping of manufacturing processes for a long period of time since the vessel must be allowed to cool before the inspection can be carried out, expose the operator to risks and lack the desired accuracy since these techniques are based on the experience and subjective opinion of the operator.

[0004] Conventional measurement systems based on the use of time-of-flight (TOF) cameras, which project a beam of light onto the surface of the coating and generate depth maps based on the detection of light by standard RGB cameras, generally collect a limited number of measurements corresponding to a limited number of points on the inner surface of the container, which may result in undetected wear in the spaces between the measured points on the refractory coating. On the other hand, conventional measurement systems using light sources generally employ complex and predefined spatial coordinate systems to reference the measurement heads (incorporating the light sources and possibly the light detectors) relative to the containers and vice versa.Any movement of the measuring heads or the container may result in invalid measurements, as the predefined spatial coordinate system is no longer valid.

[0005] There is therefore a need for systems capable of minimizing or eliminating inconsistencies in measured data regarding the wear (i.e., thickness) of the refractory lining of vessels that are configured to transport materials at temperatures above the melting point of the metal. This will allow early detection and inspection of excessive wear or small holes in the lining, thereby increasing the operational safety of the vessel and reducing operational costs associated with expensive gunning refractory lining repair operations. Such systems should also avoid the use of complex reference systems and provide reliable wear measurements in an efficient manner. Description of the invention

[0006] The invention relates to a system for monitoring an interior refractory lining of a container intended to contain molten metal. In this document, the term "container" may indifferently refer to any type of container, for example iron and steel buckets, basic oxygen furnaces (BOF), argon and oxygen decarburization (AOD) vessels, electric arc furnaces (EAF), aluminum and copper melting vessels, melting furnaces, torpedo cars (shaped buckets on rails, used to transfer molten iron from the blast furnace to the steel mill) and bottom blown furnaces (Q-BOP), or any other type of container, intended to contain high-temperature materials, for example, materials at temperatures above the melting point of the material, such as molten metals.

[0007] The term "refractory lining" may refer to a protective layer of refractory material generally installed inside the container to protect the container walls from heat, pressure and chemical attacks generated by the material contained in said container. The refractory lining may be installed in the form of bricks covering the inner surface of the container or may be molded directly onto the inner surface of the container. The term "refractory material" may refer to materials with high thermal resistance and high temperature resistance. For example, the refractory material usually installed as the inner protective layer of containers may be a magnesia (MgO)-based refractory material incorporating different magnesia aggregates and possibly binders, andalusite (A12SiO5)-based materials, magnesia combined with carbon-based refractory materials, etc. The working temperature of refractory materials may reach 2000 °C or even higher. In particular, the working temperature of refractory materials in the steel industry may be between 1500 and 1800 °C.More particularly, the refractory shotcrete material used for spraying onto the internal surfaces of the vessel to repair wear of the refractory lining may be made of any type of refractory material, for example, materials comprising sintered magnesia aggregates and binders or additives. This refractory shotcrete material may line the refractory slag line of the vessel or any other area within the vessel where the refractory lining needs to be repaired or reinforced.

[0008] The system that is the subject of the invention comprises at least one LiDAR device that can be oriented towards the refractory lining through a mouth of the container and a structure external to the container on which the at least one LiDAR device is mounted. The at least one LiDAR device comprises a laser source configured to generate a pulsed laser beam and a rotary optical encoder configured to project the laser beam onto a plurality of points on a surface of the refractory lining through the mouth of the container and a receiver configured to receive the laser beam reflected on the plurality of points on the surface of the refractory lining. The LiDAR device also comprises a controller configured to calculate a distance between the at least one LiDAR device and each of the plurality of points on the surface of the refractory lining.The controller may be a central processing unit (CPU), a microprocessor, or any other suitable hardware or software processing device.

[0009] In this document, a LiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging) device is a device for determining the distance between a laser emitter and an object or surface using a generally pulsed laser beam. The distance to the object is determined by measuring the time delay between the emission of the pulse and its detection by the reflected signal.

[0010] The laser beam projected by the LiDAR device onto the surface of the refractory lining creates a plurality of laser spots on the surface of the refractory lining. The plurality of points generates a mesh network of points representing at least partially the surface of the refractory lining. This mesh network (also known as a point cloud) may represent a portion or all of the surface of the refractory lining of the container, depending on the portion of the refractory lining to be monitored. In particular, the mesh network of points may correspond to a 3D representation of the portion of the refractory lining onto which the laser beam was projected. The LiDAR devices capture the respective laser beams after reflection on the plurality of points of the surface of the refractory lining and calculate the corresponding distance between each LiDAR device and each of the plurality of points of the surface of the refractory lining.More specifically, the LiDAR device controller measures the time it takes for the laser beam to travel from the LiDAR device's laser source to the surface of the refractory coating and back to the LiDAR device. These LiDAR devices are capable of generating mesh networks with many more points in the same amount of time than other state-of-the-art solutions such as time-of-flight cameras. This increased number of points allows for much more precise and accurate mesh networks, which improves the resolution of the resulting 3D representation of the coating.

[0011] Preferably, the measurements of the thickness of the refractory material using the system which is the subject of the invention are carried out during periods of inactivity of the container, in other words, when the container is empty or when there is only a little material left at the bottom (bath foot) after emptying the container.

[0012] In some embodiments, the system comprises at least one memory and at least one processor, such that the at least one memory is configured to, with the at least one processor, generate, with the plurality of points of the surface of the refractory lining, a mesh network at least partially representing the surface of the refractory lining; and determine the actual thickness of the refractory lining at the plurality of points of the surface from the calculated distances and corresponding predefined distances between the at least one LiDAR device and the plurality of points of the surface of the refractory lining. The processor may be a central processing unit (CPU), a microprocessor, or any other suitable hardware or software processing device.The predefined distances are the distances between the LiDAR devices and the laser points projected onto the surface of the refractory lining measured before the vessel is put into service and therefore before the refractory lining wears. Since the thickness of the refractory lining (without wear) is known, and therefore the distance between the LiDAR device and the surface of the refractory lining at any point on said surface, determining the actual distances between the LiDAR device and the worn surface of the refractory lining allows the actual thickness of the refractory lining at these points to be deduced. The au . at least one processor and the at least one memory may be located remotely from the LiDAR device such that thermal, electromagnetic and light radiation emitted by the container does not affect these components.

[0013] In some embodiments, the external structure is a robotic arm that can be moved from a first position located at a distance from the mouth of the container to a second position located at a height higher than the mouth of the container. Preferably, the system includes a single LiDAR device mounted on a free end of the robotic arm. For example, the robotic arm can be an extendable telescopic arm or a pivoting arm that extends and positions itself over the mouth of the container only when the container is empty and the monitoring operation is to be performed. For example, the free end of the robotic arm can be positioned 3 meters above the mouth of the container to ensure that heat from the container does not damage the LiDAR devices.The free end of the robotic arm can also be positioned centrally relative to the container mouth to ensure that the laser beams projected by the LiDAR devices cover the entire surface of the refractory lining.

[0014] In some embodiments, the external structure is a fixed structure located near the mouth of the container. Preferably, the fixed structure will be located at least partially at a predefined distance above the mouth of the container.

[0015] In some embodiments, the system includes two LiDAR devices mounted above the fixed structure, where each LiDAR device is oriented to scan with the laser beam a corresponding half of the interior refractory lining of the container.

[0016] In some embodiments, the system includes a first LiDAR device that is steerable onto a first portion of the surface of the refractory lining and is configured to project a first laser beam onto the first portion, generating a first mesh network that represents the first portion. Further, the system includes a second LiDAR device that is steerable onto a second portion of the surface and is configured to project a second laser beam onto the second portion, generating a second mesh network that represents the second portion. The second portion of the surface of the lining will be different from the first portion. The at least one memory will also be configured to, with the at least one processor, combine the first mesh network and the second mesh network creating a third mesh network representing a combination of the first and second portions.For example, the first LiDAR device may be configured to project its laser beam onto half of the surface of the refractory lining to generate a first mesh network representing said first half of the surface of the refractory lining and the second LiDAR device may be configured to . projecting its laser beam onto the other half of the surface of the refractory lining to generate a second mesh network representing said other half of the surface of the refractory lining. Combining said first and second mesh networks results in a third mesh network representing the entire surface of the refractory lining. In other embodiments, a different number of LiDAR devices projecting respective light beams onto the surface of the refractory lining of the vessel, scanning said laser beams over portions of the surface of the refractory lining having the same or different geometry, shape or size, may be used to obtain corresponding mesh networks which may be combined to generate larger mesh networks representing combined portions of the refractory lining of the vessel.To combine said mesh networks, the processor may use a previously defined reference system to correctly position one mesh network relative to the other mesh networks.

[0017] In some embodiments, the at least one LiDAR device has a circular field of view extending at least 70° vertically and horizontally.

[0018] In some embodiments, the at least one LiDAR device has a maximum detection range of 5 cm.

[0019] In some embodiments, the LiDAR device is integrated into a measuring head and wherein the measuring head comprises thermal insulation means.

[0020] In some embodiments, the at least one memory is configured to, with the at least one processor, generate a 3D map representing the wear of the surface of the refractory lining. This 3D map is based on the result of the comparison between the generated mesh network and the predefined mesh network. The 3D map represents the wear of the surface of the refractory lining based on the differences between the distances obtained for the points of the generated mesh network and the distances obtained for the corresponding points of the predefined mesh network. This 3D map may represent the profile of the surface of the refractory lining with different colors depending on the measured wear.To give a more accurate representation of the refractory lining surface profile, the processor may interpolate the values ​​of the differences obtained for the corresponding points to obtain intermediate values ​​that will also be used to generate the 3D map. The 3D map may include a color code indicating the degree of wear of the refractory lining surface. For example, the color red may be assigned to areas of the 3D map with wear greater than a predefined threshold, for example, 5 cm, and the color green may be assigned to areas of the 3D map with wear less than another predefined threshold, for example, 2 centimeters. Other colors, such as yellow or . orange, can be assigned to areas of the 3D map with wear ranging from 5 to 2 cm, based on other predefined thresholds. In this way, the 3D map provides an intuitive and visual representation of the integrity of the refractory lining and a user can easily determine the areas of the refractory lining on which a shotcreting operation is recommended or necessary. Similarly, the processor can automatically determine the areas of the refractory lining on which a shotcreting operation is recommended or necessary based on the cited thresholds or other thresholds.

[0021] In some embodiments, the LiDAR arrangements may include physical filters, such as zirconium dioxide filters, to filter and shield against electromagnetic and light radiation that may be received from the container during the monitoring operation. The LiDAR arrangements may further include digital filters, centered on the frequency peaks of their laser emission, to reduce received spectral noise and filter out spurious measurements generated by, for example, suspended metal particles within the container and in the area surrounding the mouth of the container.

[0022] In some embodiments, the measuring head may include a guidance system for orienting the measuring head relative to the container. Preferably, the guidance system will be coordinated with the rotary optical encoder to perform a pulsed laser beam scan of the surface of the refractory coating of interest. This guidance system may be a stepper motor with a rotary axis among other guidance systems of the prior art.

[0023] In some embodiments, the measuring head may be refrigerated. The refrigerated measuring head ensures that the electronics of the LiDAR devices and the guidance system are not damaged by heat from the container. This further allows the measuring head to be positioned closer to the mouth of the container, thereby improving the measurement obtained and the efficiency of monitoring the refractory lining.

[0024] In some other embodiments, there may be three LiDAR devices positioned at height and equidistant from each other around the mouth of the container. For example, the three LiDAR devices may be integrated into three respective measuring heads, which may be attached to a structure external to the container or to a mobile robotic arm. The three LiDAR devices will be positioned at a height such that heat from the container does not damage their optical or electronic elements. The three LiDAR devices are positioned equidistant from each other around the mouth of the container to ensure that the projected laser can scan, in a complementary manner (each laser covers approximately one-third of the total surface), the entire surface of the refractory lining.

[0025] In brief, a first aspect of the invention relates to a system for monitoring an interior refractory lining of a container intended to contain molten metal, comprising:

[0026] at least one LiDAR device which can be oriented towards the refractory lining through a mouth of the container,

[0027] a structure external to the container on which the at least one LiDAR device is mounted;

[0028] where the at least one LiDAR device comprises:

[0029] a laser source configured to generate a pulsed laser beam,

[0030] a rotary optical encoder configured to project the laser beam onto a plurality of points on a surface of the refractory lining through the mouth of the container;

[0031] a receiver configured to receive the laser beam reflected in the plurality of points on the surface of the refractory lining;

[0032] a controller configured to calculate a distance between the at least one LiDAR device and each of the plurality of points on the refractory lining surface.

[0033] In some embodiments the system comprises at least one memory and at least one processor, such that the at least one memory is configured to, with the at least one processor, perform the following operations:

[0034] generating with the plurality of points of the surface of the refractory lining a mesh network representing at least partially the surface of the refractory lining; and

[0035] determining an actual thickness of the refractory lining in the plurality of points of the surface from the calculated distances and corresponding predefined distances between the at least one LiDAR device and the plurality of points of the surface of the refractory lining.

[0036] In some embodiments the external structure is a robotic arm movable from a first position separated from the mouth of the container to a second position at a height greater than the mouth of the container.

[0037] In some embodiments the system includes a single LiDAR device mounted on the robotic arm.

[0038] In some embodiments the at least one LiDAR device has a circular field of view extending at least 70° vertically and horizontally.

[0039] In some embodiments the at least one LiDAR device has a maximum detection range of 5 cm.

[0040] In some embodiments the LiDAR device is integrated inside a measuring head and in which the measuring head comprises thermal insulation means.

[0041] In certain embodiments the measuring head comprises refrigeration means.

[0042] In some embodiments the measuring head comprises a guidance system for positioning the measuring head relative to the container.

[0043] In some embodiments, the guidance system is configured to operate in coordination with the rotary optical encoder of the at least one LiDAR device.

[0044] In some embodiments the at least one LiDAR device comprises physical filters, preferably zirconium dioxide or molybdenum dioxide filters, for filtering and protecting against electromagnetic and light radiation coming from the container.

[0045] The solution described herein can be used in the integrated steelmaking, steelmaking, glass, metallurgy, cement, waste treatment, ceramics, petrochemical and many other industries. In other words, it can be used in any industry that uses containers in which the material they contain is molten or at least reaches temperatures high enough to make the existence of a refractory material necessary. Brief description of the drawings

[0046] In order to complete the description and allow a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate an embodiment of the invention, which should not be interpreted as limiting the scope of the invention, but only as an example of how the invention can be carried out. The drawings include the following figures:

[0047] [Fig.l] represents a system for monitoring an interior refractory lining of a container, according to a particular embodiment of the invention.

[0048] [Fig.2] represents a part of the surface of the refractory coating onto which a pulsed laser beam is projected, according to a particular embodiment of the invention.

[0049] [Fig. 3] represents a front perspective view of a measuring head comprising a LiDAR device in order to monitor the wear of the surface of the refractory lining of a container, according to a particular embodiment of the invention.

[0050] [Fig.4] represents an exploded view of the measuring head 300 shown in [Fig.3].

[0051] Figures 5A and 5B represent a generated 3D map representing the wear of a portion of the surface of the refractory lining of a container, according to a particular embodiment of the invention. Detailed description of the invention

[0052] [Fig.l] shows a system 100 for monitoring an interior refractory lining 101 of a container 102. The container 102 is made of a metal or metal alloy capable of withstanding very high temperatures and its internal surface is coated with a layer of refractory material 101 which may be installed in the form of bricks lining the internal surface of the container 102 or which may be molded or sprayed directly onto the internal surface of the container 102. This layer of refractory material 101 protects the container 102 from heat, pressure and chemical attack from molten materials deposited therein. The layer of refractory material 101 substantially covers the internal surface of the container 102.

[0053] The system 100 comprises a LiDAR device 103 which is positioned centrally at a height (h) relative to the mouth 104 of the container 102, for example, 3 meters above the plane defined by the mouth 104 of the container 102. This position of the LiDAR device relative to the mouth 104 of the container 102 allows the LiDAR device 103 to project its laser beam 105 over the entire surface of the layer of refractory material 101. The LiDAR device 103 comprises a laser source emitting a laser beam whose wavelength is in the infrared spectrum, preferably between 800 nm and 1 mm and more preferably around 905 nm and emits an average power of approximately 8 W. The LiDAR device 103 will be configured to process up to 200,000 points per second.Emitting in the infrared spectrum and at this average power ensures that the laser beams projected onto the material of the refractory lining 101 are not hidden (masked) by the intense light radiation generated inside the container, so that the LiDAR device 103 is able to collect the reflected light beams. For example, the LiDAR device 103 can project its laser beam onto the surface of the refractory lining for approximately 7 seconds and can project 1,400,000 points onto the surface of the refractory lining per monitoring cycle. By exposing the LiDAR device 103 to the empty container for periods of approximately 7 seconds, the optical and electronic elements of the LiDAR device 103 are not affected by the thermal, electromagnetic and light radiation emitted by the container 102.

[0054] The LiDAR device 103 is connected to a processor 106 which may be located in a control room within the industrial facility. The cable connection 107 between the LiDAR device 103 and the processor 106 minimizes the effect of magnetic disturbances generated by the molten material within the container or by heat radiated from the container, even when empty. In addition, the cable connection 107 may include electromagnetic shielding to improve the quality and reliability of signals received in the processor 106. The LiDAR device 103 includes a molybdenum dioxide filter (not shown in this figure) to filter and shield against light and electromagnetic radiation received from the container 102. Furthermore, the LiDAR device 103 comprises a digital filter centered on the emission frequency of the laser, for example, the frequency corresponding to the emission wavelength 905 nm, in order to reduce the received spectral noise.

[0055] The LiDAR device 103 may be positioned relative to the container 102 using a robotic arm (not shown in the figure) during periods of inactivity of the container 102 and then be detached from the container during periods of production. Alternatively, the LiDAR device 103 may be attached to a fixed structure (not shown) external to the container 102.

[0056] [Fig. 2] represents a portion of the refractory lining layer 200 onto which a pulsed laser beam 201 is projected, according to a particular embodiment of the invention. The refractory lining layer 200 is formed from a plurality of bricks 202 made of refractory material. For example, the bricks 202 may be made of a magnesia (MgO)-based refractory material. The LiDAR device (not shown in this figure) is configured to project a laser beam 201 generating three laser spots 203 onto the surface of each brick 202 of the refractory lining layer 200. In this embodiment, the bricks 202 are 20 cm long and 5 cm wide, so that the distance between the laser spots 203 is approximately 5 cm.The plurality of laser spots 203 projected onto the respective spots of the bricks 202 generates a mesh network 204 representing the portion of the surface of the refractory lining layer 200 onto which the laser beam 201 is projected. The laser beam 201 moves drawing a 2D serpentine pattern on the surface of the refractory lining.

[0057] The refractory profile of the laser point set 205 is shown in graph 206 below. In this embodiment, the LiDAR device is positioned 3 meters above the mouth of the container (as shown in [Fig.l]) and the monitored portion is approximately three meters below the plane defined by the mouth of the container. Thus, the monitored portion of the refractory lining layer 200 is approximately 6 meters below the LiDAR device. Then, the laser points 203 of the predefined mesh network (mesh network generated before the refractory lining layer wears away) are projected onto the surface at a distance of 600 to 602 cm from the LiDAR device.Once the refractory lining layer 200 has been subjected to wear, the distances at which the same points of the refractory lining layer 200 are located from the LiDAR device (which is in the same position relative to the container as when the predefined distances were obtained) are between 601 and 607 cm. Thus, by comparing the respective predefined and calculated distances for each point, the wear of the refractory lining layer 200 can be obtained. This wear is between 0 and 5 cm.

[0058] The number of lines per mesh network or the number of points per line may increase or decrease depending on the duration of exposure of the LiDAR device inside the container or the accuracy requirements. In addition, the density of the points may vary depending on the area of ​​the container scanned by the LiDAR devices. For example, the LiDAR devices may project a greater number of laser points onto areas of the refractory lining layer subject to high wear.

[0059] [Fig. 3] shows a front perspective view of a measuring head 300 comprising a LiDAR device (not shown in this figure) therein for monitoring the wear of the refractory lining surface of a container, according to a particular embodiment of the invention.

[0060] The measuring head 300 is attached to the free end of a robotic arm 301. The robotic arm 301 may be an extendable telescopic arm or a pivoting arm, among other types of arms, which is configured to extend and position itself over the mouth of the container when the container is empty and the monitoring operation is to be performed. The free end of the robotic arm 301 may be positioned, for example, at least three meters above the mouth of the container to ensure that the heat of the container does not damage the LiDAR devices. The distance at which the monitoring head 300 is positioned above the mouth of the container may depend on the temperature reached by the container during the production process and, thus, its temperature during periods of inactivity.The free end of the robotic arm 301 may also be positioned centrally relative to the mouth of the container to ensure that the laser beams projected by the LiDAR device can cover the entire surface of the refractory lining. Alternatively, the measuring head 300 may be attached to a fixed structure located near the container and may be positioned centrally or off-center relative to the mouth of the container.

[0061] The measuring head 300 is fixed to the free end of the robotic arm 301 using a U-shaped adapter 302 where the side parts of the U-shaped adapter 302 are fixed using, for example, screws or welding, to the free end of the robotic arm 301. And the lower part 303 of the U-shaped adapter 302 is fixed to a metal plate 304 which is larger than the lower part 303 and protrudes forward in the laser beam emission direction of the LiDAR device. The measuring body 305 where the LiDAR device is housed is fixed to the metal plate 304. This measuring body 305 consists of a front housing 306 and a rear housing 307 which are connected by flanges 308 screwed to each other. The front housing 306 of the measuring body 305 has a front orifice 309 surrounded by a glass through which the laser beam emitted by the LiDAR device is projected. The cone 310 is a representation of the field of view or beam aperture of the LiDAR device when it is in operation.

[0062] While the measuring head 300 shown in [Fig. 3] comprises a single LiDAR device, other embodiments may comprise a different number of LiDAR devices arranged at a specific angle or orientation relative to each other. Further, other embodiments may use one or more measuring bodies 305, each of which incorporates one or more LiDAR devices. The geometry of the measuring bodies 305 may vary from one embodiment to another.

[0063] [Fig.4] represents an exploded view of the measuring head 300 shown in [Fig.3].

[0064] The lower part 303 of the U-shaped adapter 302 and the upper wall 316 of the rear housing 307 each have holes 311 through which the power supply and communication cables with the processor (not shown in this figure) pass, as well as any other cables necessary for the proper functioning of the measuring body 305, such as, for example, refrigeration cables through which a refrigerant liquid circulates to keep the LiDAR device refrigerated, etc.

[0065] The rear housing 307 comprises a rear wall 312 which can be removed to access the interior of said rear housing 307 in order to be able to fix / detach the measuring body 305 from the metal plate 304. It further comprises a front wall 313 in the form of a flange extending inwards to be fixed, using screws, to an intermediate wall 314 delimiting the spaces defined by the rear housing 307 and the front housing 306. This intermediate wall 314 has dimensions slightly smaller than the outer perimeter of the front wall 313 so that the intermediate wall 314 does not protrude from the rear wall 307. The intermediate wall 314 comprises a passage hole 315 to which a connector 319 is screwed which allows the connection of the power and communication cables of the LiDAR device 325, the pneumatic motor 328, and the cooling circuit of the measuring head 325 on either side of the intermediate wall 314.The cover 312 also allows access to these connections from the rear housing 307 without having to disassemble the measuring body 305. In other embodiments, the intermediate wall 314 may include more than one passage hole with its corresponding connector, each of them for a different cable.

[0066] The upper wall 316 of the rear housing 307 has four protrusions 317 in the form of pins which are inserted into the longitudinal guides 318 located in the metal plate 304 and which, once fixed using screws or other fixing means, allow the measuring head 305 to be moved and fixed along said guides 318. The metal plate 304 also has an orifice 320 whose width corresponds to the diameter of the holes 311 but whose length is greater to allow the passage of the cables through the mentioned holes 311 when the measuring body 305 moves back and forth along the guides 318. The metal plate 304 further comprises transverse guides 321, where alternatively the protrusions 317 of the rear housing 307 and a corresponding hole 322 can be inserted and coupled to allow the passage of the cables, which allows the measuring head 305 to move transversely along said guides 321. These guides 318, 321 with their respective holes 320, 322 allow the measuring body 305 to be fixed to the free end of the robotic arm 301, which allows position corrections to be made in the longitudinal and transverse directions.

[0067] The front housing 306 consists of an inner body 323 housing the LiDAR device 325 and the pneumatic motor 328 which serves to actuate a protective cover 329 which opens when taking measurements and closes when the LiDAR device is inactive, thus preventing heat and electromagnetic radiation from reaching the glass positioned in the hole 309 longer than necessary. The interior of the inner body 323 will be refrigerated using the refrigeration cables in order to extend the life of the LiDAR device 325 and the air motor 328. The LiDAR device 325 is inserted into the hole 324 so that only the front part thereof protrudes from said hole 324. The outer body 326 of the front housing 306 has slightly larger dimensions than the inner body 323, so that a cavity is defined between the two where a thermal protection means, for example a thermal blanket, can be inserted.The inner body 323 and the outer body 326 of the front housing 306 are screwed to the front wall 313 of the rear housing 307 via the corresponding flanges 308. The leveling shim 327 is used to facilitate the coupling of the upper wall 316 of the rear housing 307 with the metal plate 304.

[0068] [Fig.5A] represents a side view of a 3D map 400 corresponding to a part of a container, for example a tank of a melting furnace, obtained using the system 100 for monitoring a refractory lining, object of the present invention. The 3D map 400 represents the wear of a part of the refractory lining surface of the container, according to a particular embodiment of the invention. This map is generated from the measurements of the thickness of the refractory material obtained via the system 100. [Fig.5B] represents a plan view of this same tank of a melting furnace.

[0069] The degrees of wear obtained for a tank after its measurement during a furnace shutdown are represented in different colors. Thus, it can be seen that the areas of the tank closest to the bottom show wear of the refractory material interior of about 30 cm while the highest areas of this part of the tank show wear ranging from 0 to 10 cm. The bottom of the tank in [Fig.5A] is shown in a darker color because it corresponds to the bath foot, that is, at the time of measurement, there is still molten material at the bottom of the tank, which makes measurement in this area impossible. In [Fig.5B], this bath foot present at the bottom of the tank appears in green, which corresponds to a wear of 0 cm.

[0070] Based on this map, the system will automatically decide or an operator will manually decide whether to gunit defined areas of the refractory material. In some embodiments, defined wear thresholds, for example 20 cm, can be established so that an autonomous guniting system using a robotic arm inserted into the tank and controlled by a processor to which the generated 3D map 400 is provided, can automatically gunit areas with wear equal to or greater than 20 cm.

[0071] As used herein, the term "includes" and its derivatives (such as "comprising", etc.) are not to be understood in an exclusive sense, i.e., these terms are not to be interpreted as excluding the possibility that what is described may include other elements, steps, etc. The term "other", as used herein, is defined as at least a second or more. The term "coupled", as used herein, is defined as connected, either directly without any intermediate element, or indirectly with at least one intermediate element, unless otherwise indicated. Two elements may be coupled mechanically, electrically, or communicatively linked via a communication channel, route, network, or system.

[0072] The invention is obviously not limited to the specific embodiments described herein, but also covers any variation that may be envisaged by those skilled in the art (for example, with regard to the choice of materials, dimensions, components, configuration, etc.), within the general scope of the invention as defined in the claims.

Claims

Claims

1. A system (100) for monitoring an inner refractory lining (101) of a container (102) for containing molten metal, comprising: at least one LiDAR device (103) that can be oriented towards the refractory lining (101) through a mouth of the container, a structure external (301) to the container (102) on which the at least one LiDAR device (103) is mounted; wherein the at least one LiDAR device (103) comprises: a laser source configured to generate a pulsed laser beam (105), a rotary optical encoder configured to project the laser beam (105) onto a plurality of points (201) of a surface of the refractory lining (101) through the mouth of the container (102); a receiver configured to receive the laser beam reflected in the plurality of points (201) of the surface of the refractory lining (102);a controller configured to calculate a distance between the at least one LiDAR device (103) and each of the plurality of points (201) of the refractory lining surface (101).;

2. The system (100) of claim 1, comprising at least one memory and at least one processor, such that the at least one memory is configured to, with the at least one processor (106), perform the following operations: generate with the plurality of points (201) of the surface of the refractory lining (101) a mesh network (204) at least partially representing the refractory lining surface (101); and determine an actual thickness of the refractory lining (101) in the plurality of points (201) of the surface from the calculated distances and corresponding predefined distances between the at least one LiDAR device (103) and the plurality of points (201) of the surface of the refractory lining (101).

3. A system (100) according to any preceding claim, wherein the external structure is a robotic arm (301) movable from a first position separated from the mouth of the container (102) to a second position at a height greater than the mouth of the container (102).

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10. The system (100) of claim 3, comprising a single LiDAR device (103) mounted on the robotic arm (301). The system (100) of any preceding claim, wherein the at least one LiDAR device (103) has a circular field of view extending at least 70° vertically and horizontally. The system (100) of any preceding claim, wherein the at least one LiDAR device (103) has a maximum detection range of 5 cm. System (100) according to any one of the preceding claims, wherein the LiDAR device (103) is integrated within a measuring head (300) and wherein the measuring head (300) comprises thermal insulation means. System (100) according to claim 7, wherein the measuring head (300) comprises refrigeration means. The system (100) of claim 8, wherein the measuring head (300) comprises a guidance system (304, 306) for positioning the measuring head (300) relative to the container (102). System (100) according to any one of the preceding claims, wherein the at least one LiDAR device (103) comprises physical filters (307), preferably zirconium dioxide or molybdenum dioxide filters, for filtering and protecting against electromagnetic and light radiation coming from the container (102).

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