Pre-oxidation furnace flame detection lens, device, mounting structure and fire extinguishing system

Abstract

The invention relates to the technical field of pre-oxidation furnaces, in particular to a pre-oxidation furnace flame detection lens, device, mounting structure and fire extinguishing system.The detection lens comprises a long lens, the long lens is of a cylindrical structure, the open end of the long lens is connected with a camera lens, and the sealed end of the long lens is provided with a view finding small hole communicated with the interior; the first convex lens is attached to the inner wall of the sealing end of the long lens and covers the small view finding hole; the second convex lens group is arranged in the long lens, and a plurality of convex lenses are arranged in parallel at intervals along the axial direction of the long lens; wherein the length of the long lens is not less than 500mm, and the first convex lens group and the second convex lens group are both used for optically amplifying a visible light image entering from the small view-finding hole and physically attenuating high-temperature infrared rays entering from the small view-finding hole. Through the arrangement, physical attenuation of high-temperature infrared rays is realized, so that a photosensitive chip of the camera is prevented from being burnt out.

Description

Technical Field

[0001] The present invention relates to the technical field of pre-oxidation furnaces, and in particular to a flame detection lens, a device, a mounting structure and a fire extinguishing system for a pre-oxidation furnace. Background Art

[0002] The pre-oxidation furnace is one of the important equipment in the carbon fiber production process. It is mainly used for high-temperature chemical reactions and physical form changes of polyacrylonitrile-based fibers. The working temperature of the pre-oxidation furnace is usually between 200 and 300 degrees Celsius. The accumulation of heat will cause the carbon fiber precursor to catch fire, and then cause an explosion accident.

[0003] In the existing technology, PT100 platinum resistors are often used to detect flames in pre-oxidation furnaces. Fire alarms are achieved by detecting temperature. However, the PT100 platinum resistor is a slow temperature measurement device. A fire alarm signal is only issued when the flame in the furnace spreads and directly burns the PT100 platinum resistor, causing its temperature to exceed the preset fire alarm value. This process is estimated to take 3 to 5 seconds. At this time, the pre-oxidation furnace is already full of flames and is spraying flames toward the outside of the furnace. Therefore, how to more quickly identify flames to quickly extinguish the fire, prevent the flame from spreading, and thus suppress explosion accidents remains an urgent problem to be solved.

[0004] In addition, in related fields, such as Figure 1 The in-furnace image detection system of the industrial furnace shown in the figure has a temperature control cavity 02 opened on the furnace wall 01, and a high-temperature resistant glass cover 03 is set on the inner wall of the furnace wall 01. An insulation layer 04 is set on the side of the furnace wall 01 close to the temperature control cavity, and cold air is injected into the temperature control cavity 02 through the cold air pipe 05, so that the operating environment of the industrial camera 06 in the temperature control cavity 02 is below 45 degrees Celsius.

[0005] However, the inventors found that the above solution is not applicable to the pre-oxidation furnace of the carbon fiber production line. On the one hand, the carbon fiber generates a lot of heat and emits tar and dust during the oxidation process in the pre-oxidation furnace. The high-temperature resistant glass cover is easily contaminated, thereby affecting the image acquisition. On the other hand, the high-temperature glass cover will affect the temperature field in the furnace, thereby affecting the pre-oxidation reaction of the surrounding pre-oxidized raw fibers, thereby affecting the quality of the product; in addition, when shooting, traditional cameras collect thermal infrared rays of the ambient temperature in the furnace in addition to visible light images. The thermal infrared rays of nearly 300 degrees Celsius in the furnace will burn the camera's CMOS photosensitive chip. Summary of the Invention

[0006] In view of at least one of the above technical problems, the present invention provides a pre-oxidation furnace flame detection lens, device, installation structure and fire extinguishing system, which adopts the improvement of the lens to realize the detection of the flame in the pre-oxidation furnace.

[0007] According to a first aspect of the present invention, a pre-oxidation furnace flame detection lens is provided, comprising: A telephoto lens having a cylindrical structure, an open end of the telephoto lens connected to a camera lens, and a closed end of the telephoto lens having a viewfinder hole communicating with the interior; A first convex lens is attached to the inner wall of the sealed end of the long lens and covers the viewfinder hole; a second convex lens group, disposed in the long lens, and including a plurality of convex lenses arranged in parallel and spaced apart along the axial direction of the long lens; The length of the long lens is not less than 500 mm, and the first convex lens and the second convex lens group are both used to optically amplify the visible light image entering from the viewfinder pinhole, and physically attenuate the high-temperature infrared rays entering from the viewfinder pinhole.

[0008] In some embodiments of the present invention, the first convex lens and the second convex lens group magnify the object image at least twice and then form an image on the focal length of the convex lens to output a parallel light beam of the object image.

[0009] In some embodiments of the present invention, the telephoto lens includes a head portion, a steering portion communicating with the head portion, and a lens barrel portion communicating with the steering portion; The viewfinder pinhole, the first convex lens and the second convex lens group are arranged in the head, the axial direction of the head is tilted to the axial direction of the lens barrel, and the steering part has a reflecting mirror that reflects the parallel light beam output by the head to the lens barrel.

[0010] In some embodiments of the present invention, the angle between the axial direction of the head and the axial extension line of the lens barrel is 45 degrees.

[0011] According to a second aspect of the present invention, there is also provided a pre-oxidation furnace flame detection device, comprising: The pre-oxidation furnace flame detection lens as described in any one of the first aspects; A camera mechanism connected to the open end of the long lens in the pre-oxidation furnace flame detection lens; The imaging focal length of the camera mechanism is adjusted so that the parallel light beams in the long lens are projected onto the CMOS photosensitive chip of the camera mechanism.

[0012] According to a third aspect of the present invention, there is also provided an installation structure for the flame detection device of the pre-oxidation furnace as described in the second aspect, comprising: An installation sleeve is fixed on the furnace wall, and the installation sleeve has a passage leading to the furnace; A temperature-controlled cavity, wherein the camera mechanism is fixed in the temperature-controlled cavity, and the long lens is protruding from the temperature-controlled cavity; A lens cover, which is mounted on the long lens and fixed on the temperature-controlled chamber; The sliding bracket is fixed on the furnace wall, and the temperature control cavity can be relatively slidably connected to the sliding bracket, so as to allow the lens jacket to enter or be pulled out of the pre-oxidation furnace.

[0013] In some embodiments of the present invention, the diameter of the lens housing at the front end is smaller than that at the rear end, and a chamfered structure is provided at the transition point.

[0014] In some embodiments of the present invention, a semiconductor refrigerator is provided on the side wall of the temperature control cavity, and a guide groove is provided at a corresponding position on the inner wall of the temperature control cavity for guiding condensed water during cooling by the semiconductor refrigerator.

[0015] In some embodiments of the present invention, the sliding bracket has a sliding rail and a sliding seat sliding on the sliding rail, the temperature control chamber is fixed on the sliding seat, and the sliding rail is also provided with an in-position detector, which is configured to turn on the image acquisition function when detecting that the lens is extended into the furnace, and turn off the image acquisition function when detecting that the lens leaves the furnace.

[0016] According to a fourth aspect of the present invention, there is also provided a pre-oxidation furnace fire extinguishing system, comprising: The flame detection device for the pre-oxidation furnace as described in the second aspect is installed on the furnace wall of the pre-oxidation furnace; A spray device is installed on the pre-oxidation furnace to extinguish fire inside the pre-oxidation furnace; The industrial computer is in communication with the flame detection device and the spray device of the pre-oxidation furnace. The industrial computer is configured to start the spray device to extinguish the fire when flame information is detected in the image collected by the flame detection device of the pre-oxidation furnace.

[0017] The beneficial effects of the present invention are as follows: the present invention uses the viewfinder hole opened on the long lens and the cooperation of the first convex lens and the second convex lens group to amplify the visible light image entering the viewfinder hole on the one hand, and physically attenuate the high-temperature infrared rays on the other hand. Compared with the existing technology, the present invention can extend into the furnace for detection without using a high-temperature resistant glass cover, and can also avoid the camera's photosensitive chip from being burned, thereby realizing the acquisition of images inside the furnace through the lens, so as to facilitate subsequent flame detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the structure of an in-furnace image detection system for an industrial furnace in the background technology of the present invention; Figure 2 Schematic diagram of the structure of the flame detection lens of the pre-oxidation furnace in an embodiment of the present invention; Figure 3 Schematic diagram of the structure of the flame detection lens of the pre-oxidation furnace in an embodiment of the present invention; Figure 4 Schematic diagram of the structure of the flame detection device of the pre-oxidation furnace in an embodiment of the present invention; Figure 5 This is the intention of the installation structure of the flame detection device of the pre-oxidation furnace in the embodiment of the present invention; Figure 6 Schematic diagram of the cross-sectional structure of the long lens in the lens housing according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the installation position of the lens in the furnace according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the explosion-decomposition structure of the installation structure of the flame detection device of the pre-oxidation furnace according to an embodiment of the present invention; Figure 9 In the embodiment of the present invention Figure 8 A local enlarged view of point A in FIG; Figure 10 In the embodiment of the present invention Figure 8 A local enlarged view of point B in FIG; Figure 11 Schematic diagram of the system framework of the pre-oxidation furnace fire extinguishing system in an embodiment of the present invention.

[0020] Explanation of the accompanying symbols: 01, furnace wall; 02, temperature control chamber; 03, glass cover; 04, insulation layer; 05, cold air pipe; 06, industrial camera; 1, telephoto lens; 1a, head; 1b, steering part; 1c, lens barrel; 11, viewfinder pinhole; 12, first convex lens; 13, second convex lens group; 14, reflector; 2, camera mechanism; 21, CMOS photosensitive chip; 3, mounting sleeve; 4, temperature control chamber; 41, semiconductor refrigerator; 42, guide groove; 5, lens cover; 51, chamfer structure; 6, sliding bracket; 61, slide rail; 62, sliding seat; 63, in-position detector; 100, flame detection device; 200, industrial computer; 300, spray device. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] like Figures 2 to 3 The flame detection lens of the pre-oxidation furnace shown in the figure comprises a long lens 1 and a convex lens group arranged inside the long lens 1, as shown in FIG. Figure 2 As shown in: The long lens 1 is a cylindrical structure. The open end of the long lens 1 is connected to the camera lens. The sealed end of the long lens 1 has a viewfinder 11 connected to the interior. It should be noted that in the embodiment of the present invention, the aperture of the viewfinder 11 is generally 3-5 mm. With the reverse application of the pinhole imaging principle, the image inside the furnace is transmitted to the other end of the lens and captured by the camera. Please continue to refer to Figure 2 In the embodiment of the present application, the first convex lens 12 is attached to the inner wall of the sealed end of the long lens 1 and covers the viewfinder hole 11. By virtue of the focusing principle of the convex lens, the convex lens is attached to the viewfinder hole 11. On the one hand, it can magnify the image, and on the other hand, it can reversely physically attenuate the thermal infrared rays entering through the hole. It applies the reverse process of the focusing and ignition principle of the convex lens. After the thermal infrared rays entering through the viewfinder hole 11 are magnified by the convex lens, the thermal infrared ray energy is attenuated. Please continue to refer to Figure 2In the embodiment of the present application, the second convex lens group 13 is disposed within the long lens 1, and a plurality of convex lenses are arranged in parallel at intervals along the axial direction of the long lens 1; in the embodiment of the present application, the length of the long lens 1 is not less than 500 mm, and the first convex lens 12 and the second convex lens group 13 are both used to optically amplify the visible light image entering from the viewfinder pinhole 11, while physically attenuating the high-temperature infrared rays entering from the viewfinder pinhole 11. In the embodiment of the present application, the arrangement of three convex lenses optically amplifies the visible light image by approximately 11 times, while physically attenuating the high-temperature infrared rays by 11 times; the high-temperature infrared rays are then attenuated by the long lens 1 exceeding 500 mm, so that the original high temperature of 300 degrees Celsius is attenuated to below 40 degrees Celsius, thereby protecting the camera's photosensitive chip.

[0025] In the above embodiment, by means of the cooperation of the framing hole 11 opened on the long lens 1 and the first convex lens 12 and the second convex lens group 13, on the one hand, the visible light image entering the framing hole 11 is amplified, and on the other hand, the high-temperature infrared rays are physically attenuated. Compared with the prior art, it is possible to extend into the furnace for detection without using a high-temperature resistant glass cover, and it is also possible to prevent the camera's photosensitive chip from being burned, thereby realizing the acquisition of images inside the furnace through the lens for subsequent flame detection.

[0026] Based on the above embodiment, the first convex lens 12 and the second convex lens group 13 magnify the object image at least twice and then form an image at the focal length of the convex lens to output a parallel beam of the object image. Of course, it should be noted here that in the embodiment of the present application, the output parallel beam is a nearly parallel beam, and after adjusting the focal length of the camera, the image is projected onto the photosensitive chip.

[0027] In the embodiment of the present application, since the pre-oxidation furnace is mostly rectangular in cross-section, and the field of view of a general camera is directed directly in front of the camera, in order to reduce the blind spot as much as possible, the present application also makes improvements to the structure of the long lens 1, specifically as follows: Figure 3 and Figure 7As shown in the figure, the telephoto lens 1 includes a head 1a, a steering portion 1b connected to the head 1a, and a lens barrel 1c connected to the steering portion 1b; a viewfinder aperture 11, a first convex lens 12, and a second convex lens group 13 are arranged in the head 1a, with the axial direction of the head 1a tilted to the axial direction of the lens barrel 1c. The steering portion 1b has a reflector 14 that reflects the parallel light beam output by the head 1a to the lens barrel 1c. Through this structural improvement, the camera can capture the flames near the left and right furnace walls, making the blind spot of the field of view as small as possible; in addition, it should be pointed out here that in the embodiment of the present application, the angle between the axial direction of the head 1a and the axial extension line of the lens barrel 1c is 45 degrees. In order to improve the transmission efficiency of light, all lenses and reflectors 14 are coated with a high-temperature permeable film, and the reflective surface of the reflector 14 is silver-plated.

[0028] In an embodiment of the present application, a pre-oxidation furnace flame detection device is also provided, such as Figure 4 As shown in , it includes the above-mentioned pre-oxidation furnace flame detection lens and the camera mechanism 2. The camera mechanism 2 here can be an industrial camera or other image acquisition devices such as a video camera; Figure 4 As shown in the figure, the camera mechanism 2 is connected to the open end of the long lens 1 in the pre-oxidation furnace flame detection lens; and the camera mechanism 2 is adjusted in imaging focal length so that the parallel light beam in the long lens 1 is projected onto the CMOS photosensitive chip 21 of the camera mechanism 2.

[0029] like Figure 5 and Figure 8 As shown in , an embodiment of the present application further provides an installation structure of the above-mentioned pre-oxidation furnace flame detection device, including a mounting sleeve 3, a temperature control chamber 4, a lens jacket 5 and a sliding bracket 6, wherein the mounting sleeve 3 is fixed on the furnace wall, and the mounting sleeve 3 has a passage leading to the furnace; the camera mechanism 2 is fixed in the temperature control chamber 4, and the long lens 1 is protruded from the temperature control chamber 4; the temperature control chamber 4 is used to adjust the ambient temperature of the camera, and the camera here is the camera mechanism 2 in the above-mentioned pre-oxidation furnace flame detection device, and there are various specific ways to control the temperature, such as air cooling, liquid cooling and direct cooling; the lens jacket 5 is mounted on the long lens 1 and fixed on the temperature control chamber 4; specifically as Figure 6 As shown in , the end of the lens cover 5 has an inclined window, which fits with the end of the head 1a of the long lens 1. The inner diameter of the lens cover 5 is larger than the outer diameter of the long lens 1, thereby further improving the high temperature resistance of the long lens 1. Please refer to Figure 5In the embodiment of the present application, the sliding bracket 6 is fixed to the furnace wall, and the temperature control chamber 4 can be relatively slidably connected to the sliding bracket 6, so that the lens jacket 5 can enter or be pulled out of the pre-oxidation furnace. During the specific installation, the sliding bracket 6 is fixed to the outside of the furnace wall, and the sliding direction is parallel to the axial direction of the lens jacket 5, and corresponds to the installation sleeve 3. Through such an arrangement, the lens can be easily pulled out for cleaning when the front end of the lens becomes dirty. In addition, in the embodiment of the present application, the sliding bracket 6 also has a door closing structure, that is, when the lens jacket 5 is pulled out of the furnace wall, the door structure on the sliding bracket 6 automatically closes to prevent the gas in the furnace from escaping.

[0030] On the basis of the above embodiment, in order to improve the convenience of inserting the lens cover 5 into the mounting sleeve 3, as shown in FIG. Figure 6 As shown in FIG, the diameter of the front end of the lens cover 5 is smaller than that of the rear end, and a chamfered structure 51 is provided at the transition. By setting the chamfered structure 51, a conical surface is formed on the lens cover 5, which can also reduce the overflow of heat.

[0031] Please continue to refer to Figure 8 and Figure 9 In some embodiments of the present application, a semiconductor cooler 41 is provided on the sidewall of the temperature-control chamber 4, and a guide groove 42 is provided at a corresponding position on the inner wall of the temperature-control chamber 4 to guide the condensed water generated by the semiconductor cooler 41 during cooling. The sidewalls herein refer to the walls surrounding the temperature-control chamber 4. The structural arrangement of the guide groove 42 can smoothly guide the condensed water generated by the semiconductor cooler 41 during the cooling process and discharge it through the drain port at the bottom of the temperature-control chamber 4, thereby reducing the risk of water damage to the camera.

[0032] The specific sliding structure of the sliding bracket 6 is as follows Figure 10 As shown in FIG, the sliding bracket 6 has a slide rail 61 and a slide seat 62 that slides on the slide rail 61. The temperature control chamber 4 is fixed to the slide seat 62. The slide rail 61 also has an in-position detector 63. The in-position detector 63 is configured to activate the image acquisition function when it detects that the lens is inserted into the furnace and deactivate the image acquisition function when it detects that the lens is removed from the furnace. This configuration can reduce unnecessary shooting and avoid false alarms.

[0033] In the embodiment of the present application, a pre-oxidation furnace fire extinguishing system is also provided, such as Figure 11As shown in , it includes the above-mentioned pre-oxidation furnace flame detection device 100, spray device 200 and industrial computer 300; in the embodiment of the present application, the pre-oxidation furnace flame detection device 100 is installed on the furnace wall of the pre-oxidation furnace; the specific installation method can adopt the installation structure mentioned above or other structural forms; the spray device 200 is installed on the pre-oxidation furnace to extinguish the fire inside the pre-oxidation furnace; the spray device 200 can use a solenoid valve or the like to start and shut down the spraying operation; the industrial computer 300 is connected to the pre-oxidation furnace flame detection device 100 and the spray device 200 in communication, and the industrial computer 300 is configured to start the spray device 200 to extinguish the fire when flame information is detected in the image collected by the pre-oxidation furnace flame detection device 100. In addition, in the embodiment of the present application, the industrial computer 300 can also be connected to the alarm signal and the pre-oxidation furnace operation control switch, so that when a flame is identified, it can quickly act, issue an alarm and stop the operation of the pre-oxidation furnace.

[0034] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pre-oxidation furnace flame detection lens, characterized in that: include: A long lens, wherein the long lens is in a cylindrical structure, the opening end of the long lens is connected to the camera lens, and the sealed end of the long lens is provided with a viewfinder hole connected to the interior; A first convex lens is attached to the inner wall of the sealing end of the long lens and covers the viewfinder hole; A second convex lens group is disposed in the long lens, and a plurality of convex lenses are arranged in parallel and spaced apart along the axial direction of the long lens; Among them, the length of the long lens is not less than 500mm, and the first convex lens and the second convex lens group are used to optically amplify the visible light image entering from the viewfinder hole, and physically attenuate the high-temperature infrared rays entering from the viewfinder hole.

2. The pre-oxidation furnace flame detection lens according to claim 1, characterized in that: The first convex lens and the second convex lens group magnify the object image at least twice and then form an image on the focal length of the convex lens to output a parallel light beam of the object image.

3. The pre-oxidation furnace flame detection lens according to claim 2, characterized in that: The telephoto lens comprises a head, a steering portion connected to the head, and a lens barrel connected to the steering portion; The framing pinhole, the first convex lens and the second convex lens group are arranged in the head, the axial direction of the head is inclined with the axial direction of the lens barrel, and the steering part has a reflecting mirror that reflects the parallel light beam output by the head into the lens barrel.

4. The pre-oxidation furnace flame detection lens according to claim 3, characterized in that: The angle between the axial direction of the head and the axial extension line of the lens barrel is 45 degrees.

5. A flame detection device for a pre-oxidation furnace, characterized in that: include: The pre-oxidation furnace flame detection lens according to any one of claims 1 to 4; A camera mechanism connected to the opening end of the long lens in the pre-oxidation furnace flame detection lens; The imaging focal length of the camera mechanism is adjusted so that the parallel light beams in the long lens are projected onto the CMOS photosensitive chip of the camera mechanism.

6. A mounting structure for a flame detection device for a pre-oxidation furnace as claimed in claim 5, characterized in that: include: An installation sleeve is fixed on the furnace wall, and the installation sleeve has a passage leading into the furnace; A temperature control chamber, wherein the camera mechanism is fixed in the temperature control chamber, and the long lens is arranged protruding from the temperature control chamber; A lens cover, which is mounted on the long lens and fixed on the temperature control chamber; A sliding bracket is fixed on the furnace wall, and the temperature control chamber can be relatively slidably connected to the sliding bracket, so as to allow the lens jacket to enter or be pulled out of the pre-oxidation furnace.

7. The installation structure of the flame detection device of the pre-oxidation furnace according to claim 6 is characterized in that: The barrel diameter at the front end of the lens housing is smaller than the barrel diameter at the rear end, and a chamfered structure is provided at the transition point.

8. The installation structure of the pre-oxidation furnace flame detection device according to claim 6, characterized in that: A semiconductor refrigerator is provided on the side wall of the temperature control cavity, and a guide groove is provided at a corresponding position on the inner wall of the temperature control cavity for guiding condensed water when the semiconductor refrigerator is cooling.

9. The installation structure of the flame detection device of the pre-oxidation furnace according to claim 6, characterized in that: The sliding bracket is provided with a sliding rail and a sliding seat sliding on the sliding rail, the temperature control chamber is fixed on the sliding seat, and the sliding rail is also provided with an in-place detector, and the in-place detector is configured to start the image acquisition function when detecting that the lens is extended into the furnace, and to turn off the image acquisition function when detecting that the lens leaves the furnace.

10. A pre-oxidation furnace fire extinguishing system, characterized in that: include: The flame detection device for a pre-oxidation furnace as claimed in claim 5, which is installed on the furnace wall of the pre-oxidation furnace; A spray device, installed on the pre-oxidation furnace, is used to extinguish the fire inside the pre-oxidation furnace; The industrial computer is communicatively connected with the flame detection device and the spray device of the pre-oxidation furnace. The industrial computer is configured to start the spray device to extinguish the fire when flame information is detected in the image collected by the flame detection device of the pre-oxidation furnace.

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