Mobile imaging device for use in high temperature environments

Abstract

To provide: generally, a mobile imaging device which is suitable, inter alia, for use in high-temperature environments; and further a method for visualizing locations or areas in a high-temperature environment.SOLUTION: A mobile imaging device is provided which comprises at least one optical element and a casing having a through hole, where the at least one optical element is attached to the through hole inside the casing. A distal region of the casing can be exposed to a high-temperature environment during operation, where during the operation a beam can enter the casing through the opening in the distal end face and reach the optical element.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates generally to a mobile imaging device that is particularly suitable for use in high temperature environments.The present invention further relates to a method for visualizing a location or area in a high temperature environment.

[0002] To monitor processes, imaging devices or camera systems are being used more and more frequently and in a wide variety of forms, which allow ongoing processes to be visualized and thus to be adjusted and optimized or to identify deviations from a target process in a timely manner.

[0003] In processes that are carried out at relatively high temperatures or even in high temperature regions, visualization devices are increasingly used.Therefore, for example, cooled or coolable cameras or video systems have been developed, which can be used in industrial furnaces, for example, during waste incineration.They can be used, for example, to analyze flame images and adjust and optimize the combustion process accordingly.This is particularly useful in the field of waste incineration, since fuel or its composition changes frequently.

[0004] Such cameras can also be used in the iron and steel industry, where, or for example in power plants, such cameras can be used, for example, to observe slag formation during continuous operation and adjust and optimize processes accordingly, or to identify and plan cleaning and correction cycles in time.

[0005] In this case, the camera can be introduced through an opening, for example an observation hole, usually partially into the furnace or combustion chamber. Due to the large thermal effects at temperatures often significantly above 500° C. or even 1000° C., the camera housing is usually coolable and can be water-cooled during operation, so that the high temperature of the camera is usually in the range of the cooling water temperature.

[0006] Imaging may be performed through an opening in the cooled camera casing, which may be purged with dry air, for example to keep soot particles or flames away from the window.

[0007] This allows for relatively long term operation under such extreme conditions through water cooling and / or air purging.

[0008] The operator of the installation can thus observe the interior of the combustion chamber or furnace without ever approaching the vicinity of the installation, which offers a major advantage over other solutions such as, for example, observation glass in the wall of the combustion chamber.

[0009] For maintenance purposes, the camera can be removed from the combustion chamber, which can be done automatically to avoid damage to the camera, for example in the event of a loss of cooling water or cut-off air.

[0010] A coolable camera arrangement is described in DE 10 2016 202 422 A1. The camera arrangement in this case has a tube assembly to which a cooling medium can be supplied. The camera is held in the tube assembly and can be cooled during operation of the arrangement. The arrangement is suitable for thermal installations with a temperature of 100° C.

[0011] There are also various applications for such coolable camera systems in the glass industry. For example, cooled cameras are used to visualize and monitor the state of refractory materials in melting baths or batch carpets on the liquid glass melt. This allows repairs to be planned and carried out in time or even processes to be better adjusted and optimized.

[0012] However, in the case of cooled camera systems, care must be taken to ensure that a corresponding cooling system is created sufficiently reliably, which requires suitable monitoring devices, such as flow monitors, for example.

[0013] This means that rapid installation and removal of the camera is not always possible, however this is sometimes necessary, for example if the refractory material is damaged at a specific point on the inner wall of the melting tank, in order to be able to quickly inspect this exact point.

[0014] The permanent installation of a camera may also entail disadvantages in terms of the maintenance effort: for example, in order to be able to visualize the entire area inside the melting bath, several cameras must be provided which must also be supplied with an appropriate cooling medium.

[0015] In case of failure of the cooling system for the camera system, corresponding safety devices, such as automatic retraction devices, must be provided and kept in operation, which requires additional installation and engineering effort as well as corresponding space.

[0016] Furthermore, the problem of glass condensation in the cold or cooled parts of the camera arises precisely in connection with the glass melting bath.

[0017] The inventors have anticipated such drawbacks.

[0018] It is therefore an object of the present invention to provide a mobile imaging device for use in high temperature environments which avoids the problems mentioned above.

[0019] In this case, it is desirable for the imaging device to be easily operated and flexibly used so as to be able to quickly visualize potential locations in high temperature environments, for example areas of inner walls.

[0020] In this case, it would be desirable for the imaging device to be able to be used largely or ideally without any other media.

[0021] Additionally, it is desirable for the imaging device to be operable at high temperatures, in excess of 500°C, and preferably even in excess of 1000°C.

[0022] In this case, it would be desirable for the imaging device to be able to operate at such relatively high temperatures for a long enough period of time, ideally at least a few seconds, to allow the area or location to be visualized.

[0023] This problem is solved in a surprisingly simple manner by a mobile imaging device for use in high-temperature environments and by a method for visualizing a location or area in a high-temperature environment according to one of the independent claims.

[0024] In particular, in this case, the term "mobile" within the scope of the present disclosure means that the imaging device according to the present invention does not require permanent attachment during operation and can be flexibly handled, thereby providing flexible imaging at various locations in, for example, the melting device or fining device at short time intervals.

[0025] Preferred embodiments and further aspects of the invention are set out in the respective dependent claims.

[0026] Thus, in a first aspect, the present invention provides a mobile imaging device, preferably for use in high temperature environments, in particular for short-term use, comprising: At least one optical element, and a preferably elongated casing defined by a distal end surface and a proximal end surface and a throughbore extending from the distal end surface to the proximal end surface; The at least one optical element is mounted within the through hole within the casing; a distal region of the casing that can be exposed to a high temperature environment during operation and a proximal region that is away from and remains outside of the high temperature environment during operation; In operation, a beam can enter the casing through an opening in the distal end face to reach the optical element.

[0027] In this case, high temperature environment means a place or environment where an elevated temperature prevails, in particular continuously. In this case, high temperature is intended to mean a temperature above or clearly above 100° C. In particular, high temperature also means a temperature above 300° C., 400° C. or 500° C. or 600° C., preferably also above 1000° C.

[0028] Such temperatures may occur, for example, during waste incineration, for example in industrial incinerators, or in various sectors of the iron and steel industry. In particular, such high-temperature environments are also intended here, for example, as they exist in the glass industry, where they are found, for example, in the region of the upper furnace of the melting vessel.

[0029] Advantageously, the imaging device according to the invention can be operated without the supply or addition of a cooling medium during operation. This means, for example, that it is possible to dispense with the corresponding supply of cooling water for water cooling or air or compressed air for cooling. Thus, in a particularly preferred embodiment, the imaging device according to the invention can be operated without the supply or addition of a cooling medium.

[0030] During operation, the imaging device according to the invention can be exposed to a temperature of at least 600° C. without the supply or addition of a cooling medium, in which case the casing provides thermal protection for the optical element at this temperature for a period of at least 5 seconds, preferably at least 10 seconds.

[0031] This makes the imaging device according to the invention particularly simple and flexible to use, since in known furnace periscopes operating with a cooling medium, the time-consuming laying and pre-installation of cooling and / or purge lines, which often also requires the presence of several operators, is eliminated with the imaging device according to the invention.

[0032] In high temperature environments, the optical element can remain in use for periods of at least 10 seconds inside the casing, as the casing provides thermal protection to the optical element.

[0033] This allows the optical element to be protected from overheating by the casing for at least the aforementioned time period, for example allowing image detection by the optical element and / or image or signal transmission to an acquisition unit or evaluation unit.

[0034] In this case, the mobile imaging device is particularly easy to handle and can be used without further media connections if the demand is short-lived.

[0035] Although known furnace periscopes are suitable for a rather permanent, ie relatively long-term, observation of, for example, the glass melt or the furnace chamber, these systems are less suitable for short-term use.

[0036] The reason for this is, for example, that the transfer of a permanently installed furnace periscope from one position to another can only be carried out by an operator qualified for this purpose due to the required cooling equipment and support. Furthermore, such a conversion requires a relatively large amount of preparatory time, since, for example, cooling and purge lines must be re-laid or installed, and thus several hours of preparatory time must be allowed for before the corresponding inspection.

[0037] In contrast, the mobile imaging device according to the invention allows the operator to carry out corresponding inspections directly, quickly and with little effort in various locations.

[0038] This allows, for example, a particularly simple and rapid identification and evaluation of the plant condition, for example the upper furnace of the melting vessel, so that maintenance measures and repairs can be better and more simply planned.

[0039] The operation of such installations can also be improved, i.e., for example, the operation of glass melting installations when one glass has to be "remelted" to another, by providing a quick decision criterion due to the quick availability of the mobile imaging device according to the invention, thereby saving not only melting time but also raw materials and energy.

[0040] Generally, it is difficult to determine early on the exact time to perform imaging for the purpose of identifying the inner chamber or the upper furnace and the batch cover of the melting installation, in which case the mobile imaging device of the present invention offers a great advantage since it can be used quickly, simply, even multiple times and at various locations.

[0041] This makes it possible, for example, to quickly provide operators of equipment operating at high temperatures with appropriate images from inside the equipment.

[0042] The use of the mobile image pickup device is particularly simple and can be carried out by only one person, since cooling or purge lines for cooling water and the corresponding equipment can be omitted. Furthermore, the cooling media used in the known furnace chamber cameras must also be monitored, for example with respect to the flow rate or the return temperature of the cooling media. In addition to providing the cooling media, these cooling media are therefore also monitored, since in the event of a malfunction, at least part of the furnace chamber camera may reach the glass melt.

[0043] In a particularly preferred embodiment, the mobile imaging device is adapted for at least partial forward insertion through an opening, such as is often provided in such furnaces, at the distal end or face thereof, which may be, for example, a standard viewing hole, which may often have an outer diameter in the range of 30 mm to 400 mm, typically 50 mm to 250 mm.

[0044] The casing, at least in its distal region, may be similarly formed to correspond to these openings so as to allow easy insertion or pushing through these openings, preferably while still maintaining some lateral spacing to allow mobility of the movable imaging device.

[0045] Since standard viewing holes are often circular, it may be proposed that the casing, at least in the region of the distal end, is cylindrically symmetric. In this case, the diameter of the casing is advantageously smaller than the diameter of the standard viewing hole, so that the mobile imaging device can be introduced into the viewing hole at the distal end toward the front without problems. The casing may for this purpose have a diameter in the range of 20 mm to 200 mm, preferably in the range of 30 mm to 100 mm.

[0046] The substantially cylindrically symmetrical configuration of the casing, at least in the sections that are to be exposed to high temperature environments during operation, also provides advantages in terms of heat input and thermal shock resistance, since heat can be delivered uniformly across the outer surface of the casing to the interior through holes.

[0047] In order to achieve the highest possible mobility, it is proposed that the casing is not made too long. However, a certain length provides the possibility that further optical elements can also be arranged outside the high-temperature area or, for the first time, the mobile imaging device can be introduced far enough from the observation hole into the high-temperature area. In general, a casing length in the range of about 200-600 mm, preferably 300-500 mm, particularly preferably 350-450 mm, for example 400 mm, has proven to be particularly advantageous.

[0048] In order to delay the heating of the casing as long as possible after introduction into the high-temperature environment, a certain wall thickness of the casing is advantageous. The wall thickness is determined on the one hand by the outer dimensions, i.e., in the case of a cylindrically symmetrical casing, by the outer diameter, and on the other hand by the size of the through-hole. The cross-sectional shape of the through-hole corresponds in a preferred embodiment to the cross-sectional shape of the casing, so that a sufficiently constant wall thickness is provided that allows for homogeneous heating. Thus, if the casing is cylindrically symmetrical, the through-hole is likewise cylindrically symmetrical.

[0049] To be able to accommodate the optical elements, a certain minimum dimension of the through hole is advantageous, which is preferably at least 0.5 cm x 0.5 cm, or in the case of a cylindrically symmetric shape, the diameter may be at least 0.5 cm, preferably at least 1 cm or for example 2 cm.

[0050] The necessary wall thickness of the casing also depends on the thermal properties, in particular the thermal conductivity, of the material of the casing. In general, it has been found to be advantageous for the wall thickness of the casing, measured between the through-hole and the outer peripheral surface of the casing, to be at least 8 mm, preferably at least 10 mm, particularly preferably at least 15 mm or even 20 mm, if a suitable material is selected, as will be described further below.

[0051] This allows for an embodiment of a mobile imaging device to be provided in which the temperature at the hottest point inside the casing does not rise above 120° C., preferably not above 110° C., particularly preferably not above 100° C., 90° C., 80° C., 75° C. or even 70° C. over a given time period, thereby providing thermal protection for the optical elements held therein at temperatures above about 600° C., up to about 1500° C. or even up to about 1750° C. The time during which the distal end face of the imaging device is exposed to the corresponding heat can in this case be at least 30 seconds, preferably at least 60 seconds. Temperatures below 80° C. are considered not to be critical even for particularly sensitive optical elements.

[0052] In this case, the interior of the casing means in particular the area of ​​the through hole provided for receiving and / or holding at least one optical element. The temperature in the interior of the casing can be measured by a thermoelement which is attached in the through hole, for example for protective purposes, at a distance of about 10 mm from the distal end.

[0053] Such a type of thermal protection may be sufficient for the optical elements mounted therein to maintain their functionality. Optical elements mounted inside the casing can be protected against overheating in this way.

[0054] In this case, the at least one optical element can be attached to the mobile imaging device in a region or section that is exposed to a high-temperature environment for a certain period of time during operation.In other words, the at least one optical element can be inserted at least a few millimeters, preferably a few centimeters, into the high-temperature environment, for example, into the upper furnace of a glass melting tank, where the optical element is protected against the high-temperature environment by a casing for at least a short time.In some embodiments, the optical element can be inserted into the upper furnace by several decimeters, for example, 20 dm, 30 dm, or even 40 dm or more.

[0055] A time of at least 5 seconds, preferably 10 seconds, may already be sufficient to acquire a first image from inside the high-temperature environment and to get a first insight in case of problems, for example in the upper furnace.

[0056] Depending on the hot environment, the material of the casing and the wall thickness of the casing, longer times may be realized, which allows images to be detected in hot environments for correspondingly longer times. It is advantageous if thermal protection can be guaranteed for a time period of at least 30 seconds, preferably at least 60 seconds or more, for example 70, 80 or 90 seconds, i.e. the predetermined temperature is not exceeded.

[0057] It is thus possible to provide a mobile imaging device which can be exposed, at least in the region of the distal end face, to temperatures of about 1000° C. or more, preferably about 1500° C. or more, particularly preferably even to temperatures of 1600° C. or more, about 1750° C. This also makes it possible to examine from the inside the furnace chamber or upper furnace of a glass melting tank, which may have a temperature of about 1600° C. Even at temperatures of about 1600° C. or more, thermal protection could be maintained inside the casing for a period of 5 seconds or even 10 seconds.

[0058] For the housing, a material is preferably selected that can be considered temperature-stable, since it can be particularly well exposed to high outside temperatures and therefore can withstand high thermal loads. On the other hand, a high mass and a large heat capacity are advantageous in order to delay the heat transfer to the inside as long as possible after the housing is exposed to a high-temperature environment during operation, at least in the region of the distal end face. The slowest and least possible heat transfer from the outside to the inside of the housing allows a correspondingly long time for the appraisal. Furthermore, a high thermal shock resistance is also advantageous, so that the mobile imaging device can be introduced directly into the high-temperature environment without time-consuming preheating. Furthermore, a low coefficient of thermal expansion is also advantageous, since the housing is exposed to extremely high thermal loads on one side.

[0059] Particularly suitable materials include refractory materials, in particular refractory ceramic materials, i.e. ceramics or ceramic or inorganic non-metallic materials, also called technical ceramics, and also composite ceramics are possible and contemplated.

[0060] Fire-resistant materials generally refer to materials with a service temperature above 600° C., preferably materials with a cone melting point higher than SK17 according to ISO 150 or DIN 51 060, which are considered fire-resistant at temperatures up to 1500° C. or even higher.

[0061] The main components are therefore inorganic non-metallic materials, namely the oxides, silicon dioxide, aluminium oxide, magnesium oxide, calcium oxide, zirconium oxide or chromium oxide, carbon and silicon carbide.

[0062] Particularly suitable materials may be silica materials based on SiO2, such as those also used for furnace linings. Silica materials include, for example, aluminum silicate, zirconium silicate, zirconium oxide, and aluminum oxide. Particularly good results have been obtained with a ceramic material based on sintered quartz glass, available under the name "Quarzal" from Schott AG, Mainz. This material can be produced by a slip casting process, which already gives components close to the final contour, from which the housing can then be built up relatively easily.

[0063] Thus, an advantageous material may have the following properties: - Thermal expansion coefficient at 20℃~1000℃: approx. 0.2×10 -6 1 / K~2×10 -6 1 / K - Specific heat capacity from 150℃ to 1000℃: 0.94 to 1.26 kJ / kgK - Thermal conductivity at 1100℃: 0.5~2W / mK - Emissivity ε:0.3~0.8

[0064] Preferably, the material is selected depending on the given application, i.e. the given high-temperature environment, so that it is particularly simple to select for example the same material for the casing as for the furnace lining.

[0065] The temperature profile inside the casing is not only greatly influenced by heat conduction through the walls of the casing, but also by thermal radiation which may enter the casing through the openings in the distal end face, particularly during operation.

[0066] Therefore, in a preferred embodiment of the invention it is envisaged that the opening is closed at the distal end face by at least one observation window which reduces thermal radiation during operation.

[0067] The observation window is preferably made transparent in the visible or adjacent wavelength range of electromagnetic radiation in order to obtain an image from the interior chamber. Furthermore, as in the case of the casing, high thermal shock resistance is advantageous, as well as high heat resistance at the desired temperature.

[0068] Thus, advantageously, the observation window can comprise at least one protective glass, preferably made of transparent glass, for example borosilicate glass, or, in particular at planned operating temperatures above about 800° C., can comprise preferably transparent glass ceramics.

[0069] Protective glasses made of transparent glass ceramics, such as those available under the name "Robax" from Schott AG, Mainz, offer the great advantage of a low coefficient of thermal expansion, which can be advantageous when fitting into the opening of the casing. Radial expansion would otherwise lead to undesirable stress states in the casing material. The observation window can therefore also be inserted loosely, which is also advantageous from the standpoint of thermal shock resistance.

[0070] The inventors have found that the temperature input into the interior of the casing can be further significantly reduced if the protective glass has a coating that reflects radiation, particularly in the relevant wavelength spectrum, prevailing in high temperature environments.

[0071] Already with the coating on one side it was possible to achieve very good results, especially if the coating was applied on the side of the protective glass that faces the hot environment during operation, which side may also be called the distal side of the protective glass. Further improvements were achieved with the coating on both sides.

[0072] Particularly good results have been obtained with coatings that reflect infrared radiation.

[0073] This coating can be, for example, an indium oxide layer doped with tin oxide, also known as an ITO layer. Such a layer can be applied relatively easily to the protective glass by deposition, for example by cathode sputtering, under vacuum, whereby layer thicknesses of a few hundred nanometers up to a few micrometers can already be sufficient.

[0074] Furthermore, it has been found that a thin silver layer or a partially mirrored or mirrored observation window is particularly well suited, since this allows the heat radiation to be reflected very well as well. A combination of several such heat-reflecting layers is also possible and conceivable.

[0075] Such layers are particularly advantageous since, on the one hand, they have a high reflectivity in the infrared wavelength range, and, on the other hand, they have a high transmittance in the visible wavelength range, which may typically be more than 80%, preferably more than 85%, so that they have little negative effect on the visual capabilities of the imaging device according to the invention.

[0076] The protective glass may therefore in a preferred embodiment comprise a transparent glass or glass-ceramic pane which is provided on at least one side, particularly preferably on both sides, with at least a heat-reflecting layer or a (partially) mirrored portion.

[0077] In a further development of the invention, it is provided that the observation window has at least one first and a second protective glass, which are preferably arranged at a distance from one another. The at least two protective glasses are preferably arranged concentrically with one another and at a distance of 1 mm to 10 mm from one another. In this case, the protective glass arranged on the distal end side can be provided with a coating as radiation protection, as described above, and the second protective glass arranged at a distance from this can provide additional heat conduction protection.

[0078] The optical elements of the mobile imaging device may include at least one photographing unit for detecting an electromagnetic beam and / or an objective lens for image detection.

[0079] The recording unit may preferably be designed to detect electromagnetic radiation in the visible wavelength range, for which purpose a sensor, for example a CCD or CMOS sensor, a photo camera or a video camera may be provided.

[0080] A mobile imaging device offers different possibilities for positioning the optical element: the optical element may be arranged in different positions, for example in a through hole in the casing.

[0081] In one embodiment, the objective lens may be arranged in a through hole of the casing. In this case, preferably, a minimum distance to the distal end face is kept, preferably at least 5 mm, particularly preferably at least 10 mm, in order to provide sufficient thermal protection for the optical element at least for a short time when the distal end face of the mobile imaging device is fed forward into a high-temperature environment. However, at a distance from the distal end face, the field of view for the objective lens may be significantly limited, which is rather disadvantageous. To remedy this, the through hole can be conically widened towards the distal end face. Advantageously, the entire optical element is located behind at least one observation window in the direction of the proximal end, which provides thermal protection.

[0082] In one embodiment of the invention, at least the image capture unit and the objective lens may be arranged together in the through hole in the region of the distal end of the casing. Such an arrangement may already be sufficient for short-term image captures of a few seconds, for example in the range of 5 seconds, preferably 10 seconds, or for image captures at relatively low temperatures, for example below 1000° C., or preferably below 800° C. or below 500° C., and the images captured by the image capture unit can be transmitted, for example, by wire or also wirelessly via remote transmission, to a receiver, which is preferably arranged outside the high-temperature environment.

[0083] The photographing unit and the objective lens, as well as possibly further optical elements, can be easily inserted into the through hole in a compact arrangement, for example from the proximal side, to the desired position and, after activation, can be quickly withdrawn from the casing again before progressive overheating of the casing material risks damaging the optical elements.

[0084] However, in a preferred embodiment of the invention, the imaging unit and the objective lens are spaced apart from each other.

[0085] Because the objective lens is generally more heat resistant than the imaging unit, such an arrangement provides the advantage that the movable imaging device can be used for a correspondingly longer period and / or at higher temperatures before imaging must be terminated due to too high a temperature.

[0086] In one embodiment of the present invention, it is envisaged that the photographing unit is arranged in the through hole in the region of the proximal end of the casing, and the objective lens is arranged in the region of the distal end of the casing. In operation, in this arrangement, initially only the objective lens is exposed to the high temperature environment, while the proximal end, which does not enter the high temperature environment, remains at a relatively low temperature for a longer time. The terms distal and proximal regions refer to the sections of the casing that run from approximately the center of the casing in the direction of the corresponding distal or proximal end face, respectively.

[0087] During operation, the housing will heat up further due to thermal conduction, so that even with such an arrangement the duration of use is limited, lest the imaging element be damaged by thermal effects.

[0088] Therefore, in a further embodiment of the present invention, it is envisaged that at least the photographing unit is arranged outside the casing. For this purpose, the photographing unit can be held at a distance from the proximal end face, for example by a holding device. This has the great advantage that the heat transfer from the casing to the photographing unit is significantly reduced. This allows the service life or usage time to be further significantly extended or the mobile imaging device to be used at correspondingly higher temperatures, preferably at temperatures above 1000°C, or above 1200°C, or above 1400°C, or even up to a temperature range of 1500°C or more.

[0089] In order to transmit the image from the objective lens to the recording unit, it is advantageous to provide further optical elements between the objective lens and the recording unit, in particular a device for image transmission. In a preferred embodiment, the device for image transmission may include a fiber optic image guide. In the case of using a fiber optic image guide, the objective lens may image the input end of the fiber optic image guide, and a further imaging device may be configured to image the output end of the fiber optic image guide to the recording unit.

[0090] In this case, essentially flexible image guides, such as those used in endoscopes, come into consideration, but also rigid image guides, often also called boroscopes. Flexible image guides are usually made with a plastic enclosure, which allows them to react more sensitively to higher temperatures. Rigid image guides can be made with a solid glass enclosure, which makes them particularly suitable for the present invention.

[0091] In addition to light guide fibers made of plastic, light guide fibers made of or containing glass, i.e. bundles made of glass fibers, are also suitable for use in the imaging device according to the invention, since glass fibers have relatively good transmission properties even at relatively high temperatures. For example, sapphire fibers are also conceivable for the optical fiber image guide.

[0092] In alternative embodiments, it is envisioned that image transmission may operate wirelessly or via wires.

[0093] Advantageously, the image guide has a light guide fiber with a correspondingly high resolution, for example a diameter of 25 μm or less, preferably 12.5 μm, 10 μm, 7 μm or even 2.5 μm. Furthermore, a small outer diameter of the image guide is advantageous, so that sufficient space remains for the thermal protection of the surroundings, while the outer dimensions of the imaging device, in particular the outer diameter, are not excessively large.

[0094] A light guide fiber diameter of 25 μm allows the use of optical fiber image guides with an outer diameter of 10 mm or less, preferably 6 mm or less. With a smaller light guide fiber diameter, the outer diameter of the image guide can be further significantly reduced, for example to 5 mm or even to 3 mm or less, without impairing the image transmission. This allows the outer dimensions of the casing to be further reduced for the same wall thickness, which is advantageous in terms of increasing mobility on the one hand and reducing the weight of the casing on the other hand.

[0095] Of course, it is possible and envisaged to use thinner fibers to improve the image resolution. Obviously, the image capture unit or the sensor is preferably selected according to the optical resolution of the image guide, and the correspondingly required further optical elements, for example further objective lenses, are also selected accordingly.

[0096] To protect the fiber optic image guide, an insulating jacket or sheath may be provided which contains the fiber optic image guide and is arranged axially between the casing and the image guide. This may be, for example, a metallic jacket, for example a stainless steel or aluminum jacket. Another suitable material for the jacket may be a ceramic material, for example silica glass or aluminum oxide.

[0097] The robust envelope furthermore offers improved insulation as well as the possibility of forming at least the objective lens and the device for image transmission together with the imaging unit as a module or as an assembled unit.

[0098] This has the great advantage that after operation, the sensitive optical elements can be quickly separated from the casing, since the casing continues to release the heat already stored before being removed from the hot environment by thermal conduction inwards in the direction of the through holes, so that there is a further increase in the temperature inside, even after being removed from the hot environment.

[0099] A quick removal, e.g. withdrawal, of preferably all optical elements from the through-holes of the casing ensures that the optical elements are no longer heated, which further improves the usage time.

[0100] For example, it could be observed that after removing the mobile imaging device from the high temperature environment, the temperature could still increase further in the region of the through-holes for a period of about 10 minutes.

[0101] In a further development of the invention, it is envisaged that in the region of the proximal end face of the mobile imaging device, means for holding and / or moving the imaging device during operation are provided. This can be, for example, a thermally protected holding grip, which is attached on both sides to the casing. Further mounting devices can be provided for this purpose.

[0102] In a further development of the invention, it is envisaged that in the area of ​​the proximal end face, a further protective device for the operator is provided, for example a heat shield for blocking heat that may escape from the hot environment when the observation hole is opened.

[0103] In a further aspect, the present invention relates to a method for visualizing a location or area, preferably in a high temperature environment, using a mobile imaging device, preferably having at least one feature as described above.

[0104] The method envisages that during operation, a distal end of the mobile imaging device can be introduced or inserted through an opening, such as an observation hole, into a high temperature environment, such as a combustion or furnace chamber, with the proximal end of the mobile imaging device remaining outside the opening. Introducing into the high temperature environment in this case means that the distal region of the imaging device, preferably with at least one optical element, penetrates at least 10 mm, preferably at least 20 mm, 50 mm or even 100 mm or more into the high temperature environment and remains there for a predetermined time, such as 5 seconds, 10 seconds, 30 seconds or even 60 seconds or more.

[0105] The mobile imaging device can in this case be held and moved by a single operator in the area of ​​the proximal end face, which makes its use extremely flexible and simple. In this way, possible locations in high-temperature environments, for example areas of the inner walls of a glass melting installation, can be quickly visualized and inspected.

[0106] In this case, advantageously, no infrastructure needs to be provided, since the mobile imaging device operates without a medium such as cooling water or air or sealed air.

[0107] Further details of the invention emerge from the description of the illustrated embodiments and the accompanying claims. [Brief description of the drawings]

[0108] [Figure 1]FIG. 2 is a side view of one embodiment of a movable imaging device. [Diagram 2] 2 is a longitudinal cross-sectional view of the embodiment of the movable imaging device of FIG. 1. [Diagram 3] 2 is a plan view of the embodiment of the movable imaging device of FIG. 1. [Figure 4] FIG. 2 is another side view illustrating one embodiment of a movable imaging device along with various optical elements and their arrangement. [Diagram 5] FIG. 2 illustrates an example of a heat protection shield. [Figure 6] FIG. 13 shows temperature progression over time at the tip of a fiber optic image guide in a mobile imaging device. [Figure 7] FIG. 13 shows a comparison of the temperature progression inside the casing for various aspects of the observation window, measured on a prototype.

[0109] Detailed Description of the Preferred Embodiments In the following detailed description of the preferred embodiments, for the sake of clarity, substantially identical elements in each embodiment are designated by the same reference numerals. However, in order to more clearly illustrate the present invention, the preferred embodiments shown in the drawings are not necessarily drawn to scale.

[0110] FIG. 1 shows a side view of one embodiment of a mobile imaging device 10 in accordance with the present invention.

[0111] 2 shows a cross-sectional side view of the embodiment of the movable imaging device 10 of FIG. 1, and FIG. 3 shows a top view of this embodiment of the movable imaging device 10. As shown in FIG.

[0112] FIG. 4 illustrates another side view of one embodiment of the mobile imaging device 10 showing the various optical elements and their arrangement in an exploded view.

[0113] The mobile imaging device 10 is designed for use in high temperature environments, particularly for short durations, and during operation, the imaging device 10 operates without the supply or addition of a cooling medium, in accordance with the present invention.

[0114] To this end, the illustrated imaging device 10 of the illustrated embodiment comprises at least one optical element, such as a photographing element 27, an objective lens 24 (not shown in FIG. 1 ), and an elongated casing 30 extending along a central axis 31. The casing 30 is defined by a distal end face 35 and an opposing proximal end face 33. A through hole 36 (not visible in FIG. 1 ) extends along the central axis 31, thus reaching from the distal end face to the proximal end face.

[0115] The distal end surface 35 or adjacent distal region 34 may be exposed to a high temperature environment 52 during operation, such as by insertion into the furnace chamber 50 through an opening 51. As can be seen in FIG. 1, the proximal end surface 33 or adjacent proximal region 32 remains outside of the high temperature environment 52 during operation.

[0116] The objective lens 24 is mounted to and held in a distal region 34 of the casing 30 within a throughbore 36. In operation, a beam, for example an electromagnetic beam in the visible wavelength range, can enter the casing 30 through an opening in a distal end face 35 and reach the objective lens 24.

[0117] High temperature environment 52 is a location or environment where elevated temperatures prevail, particularly continuously. In this case, high temperature is taken to mean temperatures above or clearly above 100° C. In particular, high temperature also means temperatures above 300° C., 400° C., or 500° C., or 600° C., preferably even above 1000° C.

[0118] Such temperatures may occur, for example, during waste incineration, for example in industrial incinerators, or also in various sectors of the iron and steel industry. In particular, such high-temperature environments, which exist, for example, in the glass industry, are also contemplated here. The high-temperature environment 52 may thus be the upper furnace of a glass melting tank.

[0119] During operation, the mobile imaging device 10 operates without the supply or addition of a cooling medium, which means that, for example, a corresponding supply of cooling water for water cooling or air or compressed air for cooling can be dispensed with.

[0120] During operation, the mobile imaging device 10 can be exposed to temperatures of at least 600°C or more, for example temperatures of about 1000°C or more, preferably temperatures of about 1500°C or more, particularly preferably even temperatures of 1600°C or more, such as about 1750°C, without the supply or addition of a cooling medium, in which case the casing 30 provides temperature protection for the optical elements in the objective lens 24 held in the through hole at this temperature for a period of at least 5 seconds, preferably at least 10 seconds or more.

[0121] The mobile imaging device 10 is easy to handle and can be used without further media connections if the demand is short, so that the mobile imaging device 10 allows the operator to directly, quickly, and with little effort in various locations to carry out the appropriate inspection.

[0122] The mobile imaging device 10 is configured to be at least partially insertable forward at its distal end or face 35 through an opening 51, which is often provided in such furnaces 50. In the arrangement shown diagrammatically in Figure 1, the mobile imaging device 10 is inserted slightly into the furnace 50 at its distal end face 35. The opening 51 is, in this case, a standard observation hole with an outer diameter of about 100 mm.

[0123] The casing 30 is formed with cylindrical symmetry, as can be seen well in figures 2 to 4. In this case, the diameter of the casing is smaller than the diameter of the observation hole through which the casing should pass. In this embodiment, the casing 30 has an outer diameter of about 75 mm, other geometries and dimensions are also possible, for example casings 30 with diameters in the range of 20 to 200 mm or in the range of 30 mm to 100 mm are also conceivable.

[0124] The casing 30 further has a length of approximately 400 mm, although other geometries and dimensions are possible, for example casing lengths in the range of approximately 200-600 mm, or 300-500 mm, or 350-450 mm.

[0125] The through-hole 36 is formed with cylindrical symmetry, like the casing 30. The through-hole 36 has a diameter of about 30 mm in this case, although of course other diameters and geometries are possible and conceivable.

[0126] The wall thickness of the casing 30 is therefore approximately 22.5 mm, although of course other dimensions and geometries are possible and conceivable. A preferred wall thickness of the casing 30 may therefore be in the range of at least 8 mm, preferably at least 10 mm, particularly preferably at least 15 mm or even 20 mm. An excessively thick wall thickness, for example more than 100 mm, would lead to a corresponding increase in the external dimensions of the casing, which may have a negative effect on handling and mobility. It is therefore desirable for the wall thickness to be less than 100 mm, or in particular less than 50 mm, 40 mm or 25 mm. An excessively thin wall thickness would also lead to rapid heating of the casing 30, which would result in little or only a very short period of time being available for thermal protection.

[0127] A mobile imaging device 10 can be provided in which the temperature inside the casing does not rise above 120° C., preferably above 110° C., particularly preferably above 100° C., 90° C., 80° C., 75° C. or even above 70° C. over a given time period, thereby providing thermal protection for the optical elements held therein, for example the objective lens 24 held within the casing 30. This thermal protection may also be possible at temperatures above about 600° C., between 1000° C. and about 1500° C., or even up to about 1750° C., in the high temperature environment 52. The time during which the distal end face 35 of the imaging device 10 is exposed to the corresponding heat may in this case be at least 30 seconds, preferably at least 60 seconds.

[0128] An optical element, e.g., objective lens 24, is held in this case in a distal region 34 within through-bore 36 and is protected from overheating by the casing. A suitable region for accommodating an optical element, e.g., objective lens 24, is indicated diagrammatically in Fig. 2 as a distal accommodation region 37. During operation, this accommodation region 37 can at least partially enter into a high-temperature environment 52 and is in this case protected from the high-temperature environment at least for a short time by the casing.

[0129] The mobile imaging device 10 can be exposed for a short time, at least in the region of the distal end face, to temperatures of about 1000° C. or more, preferably about 1500° C. or more, particularly preferably even to temperatures of about 1750° C. Even under such high temperatures, the mobile imaging device 10 provides thermal protection inside the casing for a period of 5 or even 10 seconds, which means that the temperature in the through-hole does not rise above 120° C., preferably does not rise above 110° C., particularly preferably does not rise above 100° C., 90° C., 80° C., 75° C. or even 70° C.

[0130] Advantageously, a refractory material, in particular a refractory ceramic material, is provided for the casing 30, and thus a ceramic material or an inorganic non-metallic material is provided. Composite ceramics are also possible and conceivable. Thus, the main components of the casing 30 can be inorganic non-metallic materials, i.e. oxides or silicates such as silicon dioxide, aluminum oxide, magnesium oxide, calcium oxide, zirconium oxide or chromium oxide, carbon and silicon carbide.

[0131] Particularly suitable materials may be silica materials, such as those also used for furnace linings, including, for example, aluminum silicate, zirconium silicate, zirconium oxide, aluminum oxide.

[0132] In the illustrated embodiment, the housing 30 is manufactured from a ceramic material based on sintered quartz glass, available under the name "Quarzal®" from Schott AG, Mainz. This material can be produced by a slip casting process, which already gives components close to the final contour, from which the housing can then be built up. Thus, for example, cylindrical components close to the final contour can be cast, which can be provided with a central through hole 36 by machining after sintering. Further information on "Quarzal®" can be found in the corresponding data sheets of Schott AG, for example in the July 2007 publication "STF-1 Production Ceramics, Special Components, Examples and Recommendations".

[0133] In the illustrated embodiment, it is envisaged that the through-hole 36 is closed at the distal end face 35 by at least one observation window 25 which reduces thermal radiation during operation.

[0134] The observation window 25 is formed transparent. In this embodiment, the observation window 25 comprises a transparent glass as protective glass, for example borosilicate glass. However, in particular if the planned operating temperature is above about 800° C., the observation window may also comprise a transparent glass ceramic, for example as available under the name “Robax” from Schott AG, Mainz. The observation window 25 is inserted loosely, in which case a radial recess 38 is provided in the through hole as a receiving portion.

[0135] The observation window 25 is configured in the illustrated embodiment with a single-sided coating, which is directed to a high temperature environment during operation. In another embodiment, the observation window 25 is coated on both sides. In this example, the coating is a silver coating, and generally, a layer with high transmittance in the visible wavelength range and / or a layer that reflects infrared radiation is preferred. Partially mirrored or mirrored surfaces or a combination of both of these for the observation window 25 are also possible.

[0136] In a further development of the invention, it is provided that the observation window 25 has at least one first and a second protective glass which are arranged at a distance from each other. These at least two protective glasses are arranged concentrically with respect to each other and at a distance of 1 mm to 10 mm from each other. In this case, the protective glass arranged on the distal end side can likewise be provided with a one-sided or two-sided coating as radiation protection.

[0137] The embodiment shown in Fig. 4 further comprises a photographing unit 27 as another optical element, which in this example is formed as a photo camera and serves to detect electromagnetic radiation. The photographing unit 27 is formed to detect electromagnetic radiation in the visible wavelength range. For this purpose, a sensor, for example a CCD sensor or a CMOS sensor, or a video camera can be provided. If the device for image transmission, for example as shown in Fig. 4, has a fiber optic image guide, the entrance end of the fiber optic image guide can be connected to the objective lens 24 by means of a mounting frame 23.

[0138] The fiber optic image guide can be directly connected to the image capture unit 27 by its fiber elements being applied to the image output side. Advantageously, as an alternative to this, the output end of the fiber optic image guide can be imaged onto the image capture unit 27 by the imaging device 26. In this case, the optical free beam guidance of the imaging device 26 allows a distance between the fiber optic image guide and the image capture device 27, which allows a reduction in the heat transfer from the fiber optic image guide to the image capture device 27. Furthermore, the fiber optic image guide and / or the imaging device 26 can optionally have optical filters, for example in the form of optical bandpass filters, which transmit wavelengths desired for observation but block or reflect undesired spectral components, thereby further reducing or even blocking the direct incidence of thermal radiation on the image capture unit 27.

[0139] The mobile imaging device 10 offers different possibilities for arranging the optical elements: they may be arranged in different positions, for example within the through-hole of the casing or even outside the through-hole.

[0140] In one embodiment, the objective lens 24 may be disposed within a through hole in the casing, preferably in the distal receiving area 37 .

[0141] In this case, a minimum distance of preferably at least 5 mm, particularly preferably at least 10 mm, to the distal end face 35 is preferably maintained. In the embodiment of Fig. 2, the distal end face 35 is further provided with a conical widening 36 in order to enlarge the image field.

[0142] In one embodiment of the invention, the imaging unit 27 and the objective lens 24 may be arranged together in the through hole 36 in the region of the distal end of the casing 30, for example in a distal receiving area 37. Such an arrangement may already be sufficient for short-term imaging in the range of a few seconds, for example 5 seconds, preferably 10 seconds, or at relatively low temperatures, for example below 1000° C., or preferably below 800° C. or below 500° C., and the images taken by the imaging unit 27 can be transmitted, for example by wire or also wirelessly via remote transmission, to a receiver (not shown), which is preferably arranged outside the high-temperature environment.

[0143] The photographing unit 27 and the objective lens 24, as well as possibly further optical elements, can be easily inserted in a compact arrangement into the through hole 36, for example from the proximal end face 33, to the desired position and, after activation, can be quickly withdrawn again from the casing 30 before progressive overheating of the casing material risks damaging the optical elements.

[0144] However, in a preferred embodiment of the invention, the imaging unit 27 and the objective lens 24 are spaced apart from each other.

[0145] Because the objective lens 24 is generally more heat resistant than the imaging unit 27, such an arrangement provides the advantage that the mobile imaging device 10 can be used for a correspondingly longer period and / or at higher temperatures before imaging must be terminated due to too high a temperature.

[0146] In one embodiment of the invention, it is envisaged that the recording unit 27 is arranged in the through-hole in the region of the proximal end of the casing 30 and the objective lens 24 is arranged in the region of the distal end of the casing. In Fig. 2 both regions are clearly shown, in which next to the distal receiving area 37 there is shown, for example, a proximal receiving area 39 in which the recording unit 27 can be accommodated.

[0147] In operation, with this arrangement, initially only the objective lens 24 is exposed to the high temperature environment, while the proximal end not projecting into the high temperature environment remains at a relatively low temperature for a longer period of time.

[0148] During operation, due to thermal conduction, the casing 30 will heat up further, so that even with such an arrangement, the duration of use will be limited in order to prevent the imaging element 27 from being damaged by excessively high thermal effects.

[0149] Thus, in a further embodiment of the invention, it is envisaged that at least the photographing unit 27 is arranged outside the casing 30. For this purpose, the photographing unit 27 can be held away from the proximal end face 33 by a holding device 41, as shown in the example of FIG. 2. This has the great advantage that the heat transfer from the casing 30 to the photographing unit 27 is again significantly reduced. In this way, therefore, the downtime or the usage time can be significantly extended or the mobile imaging device 10 can be used at correspondingly higher temperatures, for example at temperatures above 1000° C., or above 1200° C., or above 1400° C., or even up to a temperature range of 1500° C. or higher.

[0150] In order to transmit the image from the objective lens 24 to the recording unit 27, advantageously further optical elements can be provided between the objective lens 24 and the recording unit 27, in particular a device for image transmission 22. In a preferred embodiment, the device for image transmission may comprise a fiber optic image guide. In another embodiment, the image transmission may take place wirelessly or by wire.

[0151] Advantageously, the image guide has a light guide fiber with a correspondingly high resolution, for example a diameter of 25 μm or less, preferably 12.5 μm, 10 μm, 7 μm or even 2.5 μm. Furthermore, a small outer diameter of the image guide is advantageous, so that sufficient space remains for the thermal protection of the surroundings, while the outer dimensions of the imaging device 10, in particular the outer diameter, are not excessively large.

[0152] A light guide fiber diameter of 25 μm, as provided in the embodiment of FIG. 4, allows the use of a fiber optic image guide having an outer diameter of, for example, 10 mm or less, preferably 6 mm or less. With a smaller light guide fiber diameter, the outer diameter of the image guide can be reduced even more significantly, for example to 5 mm or even 3 mm or less, without compromising image transmission. The light guide fiber is in this embodiment a glass fiber.

[0153] To protect the fiber optic image guide, an insulating cover or cladding tube 21 may be provided which receives and holds the fiber optic image guide. The cladding tube 21 may be made of a metallic or ceramic material, and in this embodiment is made of stainless steel or aluminum. The robust cladding tube further provides improved insulation as well as the possibility of forming at least the objective lens 24 and the device for image transmission 22 together with the imaging unit 27 as a module or assembly unit 20.

[0154] This has the great advantage that after operation, the sensitive optical elements can be quickly separated from the casing 30, since the casing may still release the heat already stored therein by thermal conduction in the direction of the through holes 36, before being removed from the high-temperature environment, where the temperature may further increase after being removed from the high-temperature environment.

[0155] A quick removal, e.g. withdrawal, of preferably all optical elements from the through-holes of the casing ensures that the optical elements are no longer heated, which further improves the usage time considerably.

[0156] In the embodiment shown in Fig. 2, it is envisaged to provide in the region of the proximal end face 33 of the mobile imaging device 10 means for holding and / or moving the imaging device 10 during operation. For this purpose, thermally protected holding grips 42 are provided, which are connected to the casing 30 on both sides by means of mounting devices 40 (see also Fig. 3 for example).

[0157] In a further development of the invention, it is envisaged to provide a further protective device for the operator in the area of ​​the proximal end face 31, for example a heat shield 43 for blocking heat that may escape from the high-temperature environment when the observation hole is opened.

[0158] FIG. 5 shows an embodiment for such a heat shield 43 .

[0159] The temperature profile inside the casing 30 according to the invention exposed to a high-temperature environment with a temperature of 1400° C., such as may occur, for example, in the upper furnace of a glass melting tank, was determined at various times on the basis of simulations.

[0160] In this case, it was assumed that the distal region of the casing 30, having a wall thickness of about 22 mm to about 70 mm, was inserted into a high temperature environment, and the simulation was based on a protective glass.

[0161] As material, in the simulation, sintered quartz glass was used for the casing 30, the outer diameter of which was approximately 75 mm. As starting or starting temperature, a temperature of approximately 30° C. was taken as the basis.

[0162] The results show that even after 60 seconds, the entire area within the through hole 36 still has a temperature below 100° C., particularly between 30° C. and 100° C., whereas the surrounding area of ​​the casing, particularly the area of ​​the distal end face 35, already has a temperature above 1000° C. and up to 1400° C. The optical elements inside the casing 30 are therefore protected from excessively high thermal effects for at least the aforementioned time.

[0163] However, inside the casing, large temperature differences occur over very short distances, so it is particularly important to select materials with low thermal expansion properties or very good thermal shock properties.

[0164] The temperature profile inside the casing 30 according to the present invention exposed to a high-temperature environment having a temperature of 1400° C. was also simulated, in which case an optical fiber image guide with a coating was used in the through hole 36, and was determined based on further simulations, in particular at various times.

[0165] Again, it is shown that the temperature inside the casing can be maintained at less than 100°C for 30 seconds, which is not considered to be critical for the optical elements provided, so that the objective lens 24 and the optical fiber image guide and / or the photographing unit 27 can be used reliably inside the casing for the above period. This optical fiber image guide is shown to be exposed to temperatures of 30°C to approximately 90°C after 60 seconds of use.

[0166] 6 shows the temperature profile over time at the tip of an optical fiber image guide inserted in a casing 30, which is provided with a cladding tube in this case. The distal opening is closed by an observation window 25. The mobile imaging device according to the invention can advantageously be exposed during operation to high-temperature environments having temperatures of about 1000° C. or more, preferably about 1500° C. or more, particularly preferably even 1600° C. or more, or even up to about 1750° C., but the results obtained by simulation at 1400° C. already show its important advantages.

[0167] Finally, Fig. 7 shows a comparison of the actual temperature profiles inside the casing for various configurations of the casing and various coatings of the observation window 25. Measurements or profiles a and b were carried out with a thermoelement in a blind hole with a blind hole diameter of 5 mm (profile a) and in a blind hole with a blind hole diameter of 30 mm (profile b) in a casing without an observation window as a preliminary test. Measurements or profiles c, d, e and f were carried out in a casing with an observation window and various coatings of the protective glass, where the thermoelement was pressed directly through the casing against the protective glass. The distal end was exposed to a temperature of 1400°C for a period of 30 seconds.

[0168] Both progressions a and b show the temperature progression in blind holes of different diameters, which are 5 mm (progression a) and 30 mm (progression b). In this comparative example, for testing purposes, a casing without a distal opening was used. The thermoelement is therefore only separated from the hot environment by a 15 mm thick wall and the end faces of the casing.

[0169] The coatings in transitions c, d, e and f are as follows: C: No coating e: Inner coating d: Outer coating f: Inner and outer coating

[0170] In transition c (without coating), it is clearly visible that, due to thermal radiation, the temperature increases significantly almost abruptly with the insertion of the structure into the hot environment. After 5 seconds, the limit of 100° C. is reached or exceeded.

[0171] The influence of the coating can be clearly seen in the examples of transitions d, e and f, where, when using a protective glass coated on both sides, the temperature maximum is only reached behind the protective glass, i.e., for example behind a possible accommodation area 37 for an optical element, after about 60 seconds, which in this case is about 80° C.

[0172] The mobile imaging device 10 may be used for visualization of locations or areas within a high temperature environment 52 .

[0173] To this end, during operation, the distal end of the mobile imaging device 10 can be inserted through the opening 51 into the high temperature environment 52 , with the proximal end of the mobile imaging device 10 remaining outside of the opening 51 .

[0174] Simulations have shown that usage times of, for example, 5 seconds, 10 seconds, 30 seconds or even 60 seconds or more are possible.

[0175] The mobile imaging device can then be held and moved by a single operator, making its use extremely flexible and simple. In this way possible locations can be quickly visualized and inspected in high temperature environments 52, for example in the inner wall areas of a glass melting installation.

[0176] In this case, advantageously, no infrastructure needs to be provided since the mobile imaging device 10 operates without a medium such as cooling water or air or sealed air.

Claims

1. A movable imaging device, preferably for use in high-temperature environments, and especially for short-term use, At least one optical element, and It has a casing that is preferably elongated and extended, defined by a distal end face, a proximal end face, and a through hole extending from the distal end face to the proximal end face. The at least one optical element is mounted inside the casing within the through hole. The distal region of the casing can be exposed to the high-temperature environment during operation, while the proximal region is located away from the high-temperature environment during operation and remains outside the high-temperature environment. During operation, the beam can enter the casing through the opening at the distal end face and reach the optical element. Preferably, the imaging device is a movable imaging device that can be exposed to a temperature of at least 600°C during operation without the supply or addition of a cooling medium, in which case the casing provides thermal protection for the optical elements at the said temperature for a time of at least 5 seconds, preferably at least 10 seconds.

2. The movable imaging apparatus according to claim 1, wherein the temperature inside the casing does not rise above 120°C, preferably above 110°C, and particularly preferably above 100°C, 90°C, 80°C, 75°C, or even above 70°C, thereby providing thermal protection for the optical element.

3. The movable imaging device according to claim 1 or 2, which can provide the thermal protection for a period of at least 30 seconds, preferably at least 60 seconds, during operation.

4. The movable imaging device according to claim 1 or 2, wherein the imaging device can be exposed to a temperature of about 1000°C or higher, preferably about 1500°C or higher, and particularly preferably even 1600°C or higher, or about 1750°C, during operation.

5. The casing comprises or is based on at least one fire-resistant material, preferably silica such as aluminum silicate, zirconium silicate, zirconium oxide, or aluminum oxide (SiO₂). ２ A movable imaging device according to claim 1 or 2, comprising at least one fire-resistant ceramic material based on ).

6. The movable imaging device according to claim 1 or 2, wherein the casing is formed cylindrically symmetrically at least in the region of the distal end, and / or the through hole is formed cylindrically symmetrically.

7. The movable imaging device according to claim 6, wherein the casing has a diameter in the range of 20 mm to 200 mm, preferably in the range of 30 mm to 100 mm, and / or preferably has a length in the range of 200 mm to 600 mm, preferably in the range of 300 mm to 500 mm, and particularly preferably in the range of 350 mm to 450 mm.

8. The movable imaging device according to claim 1 or 2, wherein the wall thickness of the casing is measured between the through hole and the outer surface of the casing and is at least 8 mm, preferably at least 10 mm, and particularly preferably at least 15 mm or 20 mm.

9. The movable imaging device according to claim 1 or 2, wherein the opening at the distal end face is closed by at least one observation window.

10. The movable imaging device according to claim 9, wherein the at least one observation window includes at least one protective glass or sapphire glass, preferably made of transparent glass, preferably borosilicate glass, or silica glass, or preferably transparent glass ceramics.

11. The movable imaging device according to claim 10, wherein the at least one protective glass has at least one single-sided coating, the coating preferably located distal to the protective glass, or the at least one protective glass has double-sided coatings.

12. The movable imaging device according to claim 11, wherein the coating comprises at least one heat-reflective layer, preferably a silver coating and / or an ITO coating and / or a mirror-finished portion and / or a partially mirror-finished portion.

13. The movable imaging device according to claim 1 or 2, wherein the observation window preferably has at least one first protective glass and a second protective glass arranged at intervals from each other, the interval between them being 1 mm to 10 mm.

14. The movable imaging device according to claim 1 or 2, wherein the optical element includes a shooting unit for detecting an electromagnetic beam and / or an objective lens for image detection.

15. The movable imaging device according to claim 14, wherein the imaging unit is preferably formed to detect an electromagnetic beam in the visible wavelength range and has a sensor, such as a CCD sensor or CMOS sensor, a photocamera, or a videocam.

16. The movable imaging device according to claim 14, wherein the objective lens is disposed within the through hole in the distal region of the casing.

17. The movable imaging device according to claim 14, wherein the imaging unit and the objective lens are arranged together in the through hole in the distal region of the casing.

18. The movable imaging device according to claim 14, wherein the objective lens is located in the distal region of the casing and the imaging unit is located in the proximal region of the casing.

19. The movable imaging device according to claim 14, wherein the objective lens is located in the distal region of the casing and the imaging unit is located outside the casing.

20. The movable imaging device according to claim 14, wherein an image transmission device, preferably an optical fiber image guide, is provided between the objective lens and the imaging unit.

21. The movable imaging device according to claim 20, wherein the optical fiber image guide is held within an insulating coating or coating tube.

22. The movable imaging apparatus according to claim 1 or 2, wherein at least the objective lens and the image transmission device and / or the imaging unit are formed as an assembly unit or as a module.

23. A method for visualizing a location or area, preferably in a high-temperature environment, comprising using the movable imaging device described in claim 1 or 2.

24. The visualization method according to claim 23, wherein, during operation, the distal end of the movable imaging device can be introduced through an opening into the high-temperature environment by at least 10 mm, preferably at least 20 mm, 50 mm, or even 100 mm or more, and remains there for a predetermined time, preferably 5 seconds, 10 seconds, 30 seconds, or even 60 seconds or more.

Images