Mining flame sensor based on ultraviolet image sensing technology

Abstract

The invention relates to a mining flame sensor based on an ultraviolet image sensing technology, and belongs to the technical field of mining area flame detection. The sensor aims at solving the problems that a traditional mining flame sensor is short in detection distance and high in false alarm rate due to the fact that the traditional mining flame sensor is easily interfered by ambient light and a non-fire ultraviolet source. According to the technical scheme, the device comprises a shell, an ultraviolet detection module arranged in the shell and a visible light imaging module arranged on the shell; the ultraviolet detection module adopts an ultraviolet detection chip formed by a zinc oxide nanorod array to capture a flame ultraviolet radiation signal, and the visible light imaging module is used for acquiring visible light image information such as flame form, flicker frequency and spatial distribution; the sensor cooperatively recognizes the flame by fusing the ultraviolet radiation signal and the visible light image information. According to the invention, high sensitivity and rapid response are realized, real flames and interference sources can be effectively distinguished, the detection reliability and false alarm resistance are obviously improved, and the method is suitable for safety monitoring in a complex mine environment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of mine flame detection, and relates to a mine-used flame sensor based on ultraviolet image sensing technology. BACKGROUND

[0002] In the complex environment of coal mining, gas and coal dust explosion is an extremely serious safety threat, which not only directly endangers the lives of miners, but also causes devastating damage to mine equipment, resulting in significant economic losses. Although existing preventive measures such as ventilation systems and gas extraction can reduce the risk of explosion to some extent, once an explosion occurs, the traditional safety system is difficult to achieve rapid and effective suppression to prevent its catastrophic spread. Therefore, mine explosion isolation and suppression technology emerges as the times require, and the core premise of this technology is to achieve millisecond-level explosion detection, of which the most critical link is the rapid detection of the initial flame of explosion.

[0003] At present, the traditional flame sensor widely used in mine explosion isolation and suppression systems mostly adopts detection methods such as single ultraviolet phototube, double ultraviolet phototube, or combination of ultraviolet phototube and infrared detector. The working principle of this type of sensor is to detect ultraviolet or infrared radiation of specific wavelengths. However, this single detection principle has inherent defects. First of all, they are easily disturbed by environmental light, especially strong light or sunlight, thus causing false alarms. Secondly, non-fire ultraviolet sources such as electric welding arc light and sparks generated by equipment friction in mine operations also often cause false triggering of the sensor. In order to meet the industry standard requirement of responding to a 1 candlepower flame within 5 milliseconds at a distance of 5 meters, the detection threshold of these sensors is usually set very sensitive, but this further sacrifices the stability of the sensor, making the false alarm problem more prominent, which seriously affects the reliability of the explosion isolation and suppression system.

[0004] In order to overcome the above-mentioned defects, there is an urgent need in the field for a new type of flame sensor that not only has extremely high detection sensitivity and extremely fast response speed, but also can accurately distinguish between real flames and interference sources, achieve long-distance and high-reliability detection, and thus truly improve the level of mine safety protection. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a mine-used flame sensor with high sensitivity, high reliability, rapid response and effective avoidance of false alarms. Specifically, the present application mainly solves the following technical problems:

[0006] Solve the problem of short detection distance of traditional mine-used flame sensors, and improve the effective detection distance to not less than 30 meters.

[0007] The application solves the problem that traditional mine flame sensors are easily affected by strong light, sunlight and electric arc and thus generate false alarms while pursuing fast response, and significantly reduces the false alarm rate while ensuring that the response speed is not greater than 1 millisecond.

[0008] To achieve the above object, the application provides the following technical scheme.

[0009] The application provides a mine flame sensor based on ultraviolet image sensing technology, which comprises a shell, an ultraviolet detection module arranged in the shell, the ultraviolet detection module comprising a photoelectric sensor of an ultraviolet detection chip composed of zinc oxide nanocolumn arrays, and a visible light imaging module arranged on the shell and used for capturing visible light band radiation characteristics of a flame.

[0010] The application provides a mine flame sensor based on ultraviolet image sensing technology, which comprises:

[0011] The shell 1;

[0012] The ultraviolet detection module 2 is arranged in the shell 1, and the ultraviolet detection module 2 comprises a photoelectric sensor of an ultraviolet detection chip composed of zinc oxide nanocolumn arrays.

[0013] The visible light imaging module 5 is arranged on the shell 1 and used for capturing visible light band radiation characteristics of a flame.

[0014] The ultraviolet detection module 2 is used for acquiring ultraviolet radiation signals of a flame, the visible light imaging module 5 is used for acquiring visible light image information of a flame in terms of shape, flicker frequency and spatial distribution, and the sensor fuses the ultraviolet radiation signals and the visible light image information to identify the flame.

[0015] Further, the ultraviolet detection chip is prepared by using wafer-level 3D stacking heterogeneous sensor integration technology and based on zinc oxide modified materials.

[0016] Further, the photoelectric sensor further comprises a pixel circuit and a line control board; the ultraviolet detection chip is used for receiving flame signals and converting the flame signals into electric signals, the pixel circuit is used for amplifying and processing the electric signals, and the line control board is used for collecting and transmitting the processed electric signals.

[0017] Further, the visible light imaging module 5 is used for capturing the diffusion, smokeless, blue edge flame shape of the flame, the flicker frequency of 20-50Hz, and the spatial distribution and motion trajectory of the flame.

[0018] Further, the zinc oxide nanocolumn array is prepared by growing a zinc oxide film on a silicon wafer substrate, and then growing a nanocolumn array on the zinc oxide film by a sol-gel method or a hydrothermal method.

[0019] Further, the interval of the zinc oxide nanocolumn array is achieved by controlling the concentration of a precursor solution, wherein the photoelectric response performance is optimal when the concentration of the precursor solution is 0.05 mol / L.

[0020] Further, the zinc oxide nanocolumn array is subjected to a post-processing step, and the post-processing step includes introducing an anti-reflection layer by surface modification, coating a protective film by chemical vapor deposition (CVD), or performing surface hydrogen passivation treatment.

[0021] Further, the sensor further comprises a protective sleeve 3 arranged outside the visible light imaging module 5 and made of quartz glass or sapphire material.

[0022] Further, the sensor triggers an alarm only when the signals of the ultraviolet detection module 2 and the visible light imaging module 5 are determined to be abnormal synchronously.

[0023] Further, the shell 1 is provided with a connecting base 4 at the bottom for connecting an external tripod.

[0024] Further, the detection sensitivity of the ultraviolet detection module 2 is 1 mu W / cm 2 Hereinafter, the response time is not greater than 1 millisecond, and the effective detection distance is 1-50 meters.

[0025] Further, the sensor further comprises a processor for aligning and correlatively analyzing the ultraviolet radiation signal and the visible light image information in time and space, and triggering an alarm only when the double-channel signals synchronously meet a preset flame characteristic model.

[0026] The beneficial effects of the present application are:

[0027] (1) The application innovatively adopts a dual-spectrum collaborative strategy of ultraviolet detection and visible light imaging to realize the leap from "signal sensing" to "visual recognition". The ultraviolet detection module quickly captures the ultraviolet radiation of the flame, while the visible light imaging module obtains the visual features such as the shape, color and flicker frequency of the flame. The system triggers an alarm only when the dual-channel signals simultaneously meet the flame characteristics through multi-source information fusion analysis, effectively eliminates single interference sources such as electric welding arc light and sunlight reflection, reduces the false alarm rate to below 10%, and greatly improves the reliability in complex mine environments.

[0028] (2) The core of the ultraviolet detection module adopts a 3D nanometer pillar array structure based on the third-generation wide-bandgap semiconductor zinc oxide material. Compared with the traditional planar film structure, the 3D nanometer pillar array greatly increases the photosensitive area and light absorption path, significantly improving the photoelectric conversion efficiency. This enables the sensor to capture early weak flame ultraviolet signals, with a detection sensitivity of 1 mu W / cm 2 Below, the response speed is not greater than 1 millisecond, which wins valuable time for the rapid start of the explosion suppression system.

[0029] (3) The application integrates high-performance back-illuminated photoelectric sensing technology, wafer-level 3D stacked heterogeneous sensor integration technology, and high-definition image sensor manufacturing technology based on zinc oxide modification, supporting 800x600 pixel high-resolution imaging. This not only enables the spatial distribution of the flame to be clearly visualized, but also extends the effective detection distance of the sensor from medium-short distance to 1 to 50 meters, meeting the monitoring needs of large roadways and working faces.

[0030] (4) The overall structure of the application is compact, the shell is made of frosted pure black material to reduce signal interference, the camera is equipped with a quartz glass or sapphire protective sleeve, which is scratch-resistant and wear-resistant, ensuring optical transmittance and long-term stability. The bottom is provided with a standard connecting base for easy on-site installation and fixation. In summary, the application has the advantages of simple structure, easy operation and moderate size, and has great practical significance for ensuring the safety of coal mining.

[0031] Other advantages, objects and features of the present application will be in part apparent and in part pointed out below in the specification, and in part will be observed from the hereinafter as best matters of practice, the principles disclosed in the application. The objects and other advantages of the present application can be achieved and obtained by the following description. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the preferred detailed description of the present application will be described below in combination with the drawings, in which:

[0033] Figure 1A structure diagram of a mine-used flame sensor based on ultraviolet image sensing technology according to the present application is shown in the figure.

[0034] Figure 2 A back view of the mine-used flame sensor according to the present application is shown in the figure, mainly showing the structure of the connecting base.

[0035] Reference signs: 1, housing; 2, ultraviolet detection module; 3, protective sleeve; 4, connecting base; 5, camera. DETAILED DESCRIPTION

[0036] The advantages and effects of the present application can be easily understood by those skilled in the art from the description of the embodiments. The present application can also be implemented or applied in different specific embodiments, and the details in the description can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be noted that the figures provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner, and the features in the following embodiments and examples can be combined with each other without conflict.

[0037] The figures are only used for illustrative explanation, and the representation is only a schematic diagram, not a physical diagram, and should not be understood as a limitation of the present application. In order to better illustrate the embodiments of the present application, some components in the figures may be omitted, enlarged or reduced, and do not represent the actual size of the product. It is understandable for those skilled in the art that some well-known structures and their descriptions in the figures may be omitted.

[0038] The same or similar reference signs in the figures of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back" and the like is based on the orientation or position relationship shown in the figures, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the position relationship in the figures are only used for illustrative explanation, and should not be understood as a limitation of the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0039] Embodiment 1

[0040] The present embodiment provides a mine-used flame sensor based on ultraviolet image sensing technology, the overall structure and working process of which are as follows.

[0041] Please refer to Figure 1 and Figure 2 , Figure 1 The three-dimensional structure of the present sensor is shown in the figure, Figure 2The view of the connecting base is shown. The sensor mainly comprises a shell 1, an ultraviolet detection module 2 arranged inside the shell 1, a camera 5 arranged outside the shell 1, a protective sleeve 3 covering the outside of the camera 5, and a connecting base 4 arranged at the bottom of the shell 1.

[0042] The shell 1 is a bearing structure of the whole sensor, which is made of frosted material, the outer wall is smooth, and the color is pure black. Such design can maximize the avoidance of unnecessary reflection or interference of the shell on the detection signal.

[0043] The camera 5 is a visible light imaging module, which is installed on one side of the shell 1 and is used for capturing real-time visible light images of the monitoring area. The camera 5 in the embodiment is equipped with high dynamic range and low illumination imaging capability, which is specially used for capturing the weak radiation characteristics of the flame in the visible light band. These characteristics include the flame-specific morphology such as diffusivity, smokeless, blue edge, etc., and the flame-specific flicker frequency, which is usually between 20 Hz and 50 Hz, and the spatial distribution and motion trail of the flame.

[0044] The protective sleeve 3 is arranged outside the camera 5 and is used for protecting the lens of the camera 5. In order to ensure long-term stable work in the dusty and humid environment of the mine, the protective sleeve 3 is made of high-hardness quartz glass or sapphire material, which can effectively prevent scratching and wear, and can also ensure high optical transmittance, avoid signal attenuation and image quality degradation.

[0045] The connecting base 4 is arranged at the bottom of the shell 1, and a hole for fixing is arranged on the connecting base 4. The connecting base 4 can be connected with the external tripod or the support in the mine through bolts and other fasteners, so as to stably install the whole detection device at the position to be monitored.

[0046] The ultraviolet detection module 2 is a core component for realizing the sensing of the flame ultraviolet signal, which is fixed on the inner wall of the shell 1. The module can automatically adjust its working state according to the change of the external light intensity, so as to achieve the best detection effect.

[0047] The working process of the sensor of the present embodiment is as follows: first step: installation and deployment. The sensor is fixed at a key position in the coal mine tunnel or coal mining face using the connecting base 4, and the orientation of the camera 5 is adjusted so that it faces the area to be monitored. Second step: real-time monitoring. After the sensor is powered on, the ultraviolet detection module 2 and the camera 5 start working at the same time, and the monitored area is continuously scanned in real time. Third step: dual-spectrum signal acquisition. When a suspected flame appears in the monitored area, the ultraviolet detection module 2 will capture the ultraviolet radiation signal of a specific wave band generated by the flame. At the same time, the camera 5 will also capture the dynamic visible light image of the suspected flame, including its shape, color and flickering characteristics. Fourth step: information fusion and intelligent identification. The processor inside the sensor aligns and correlates the ultraviolet signal from the ultraviolet detection module 2 and the visible light image information from the camera 5 in time and space. The system will determine whether the intensity of the ultraviolet signal exceeds the preset threshold, and at the same time analyze whether the visible light image matches the visual characteristics of a real flame, such as whether there is a 20-50 Hz flicker, whether there is a blue edge, etc. Fifth step: alarm decision. Only when the ultraviolet signal and the visible light image information are both abnormal, that is, the characteristics of the two channels match the preset flame model, will the system finally confirm it as a real flame event, and immediately trigger an alarm signal to transmit the information to the mine explosion suppression system. If only the ultraviolet signal is present without corresponding visible light flame characteristics, such as electric welding arc light or sunlight reflection, the system will determine it as interference and ignore it, thereby effectively avoiding false alarms.

[0048] Embodiment 2

[0049] Based on Embodiment 1, the present embodiment further details the internal structure of the ultraviolet detection module 2 and the preparation method of the core component, the ultraviolet detection chip.

[0050] The ultraviolet detection module 2 is mainly composed of a photoelectric sensor, which integrates an ultraviolet detection chip, a pixel circuit and a line control board inside.

[0051] The ultraviolet detection chip is the core of the module, responsible for receiving and detecting the ultraviolet signal of the flame and efficiently converting it into an electrical signal. The ultraviolet detection chip in the present embodiment is made of the third generation of wide bandgap semiconductor zinc oxide material, combined with multiple advanced manufacturing technologies, including high-performance back-illuminated photoelectric sensing technology, wafer-level 3D stacked heterogeneous sensor integration technology and large-size device lithography splicing technology, finally preparing a high-definition image sensor.

[0052] The pixel circuit is tightly integrated with the ultraviolet detection chip, which is responsible for effectively amplifying and preliminarily processing the weak electrical signal generated after the chip conversion, in order to improve the signal-to-noise ratio.

[0053] The line control board is responsible for collecting, analog-to-digital converting and transmitting the electrical signal processed by the pixel circuit, and finally delivering the digitized ultraviolet signal data to the back-end processor for fusion analysis with visible light image information, or even imaging on the display screen to complete the perception of the flame pattern.

[0054] In this embodiment, the core photosensitive structure of the ultraviolet detection chip is a zinc oxide nanocolumn array. The preparation process of the array is as follows: first step: substrate and seed layer preparation. A silicon wafer is selected as the substrate, and a uniform and dense zinc oxide film is grown on the silicon wafer substrate as a seed layer using metal organic chemical vapor deposition (MOCVD) technology. Second step: growth of nanocolumn array. A hydrothermal method is used to grow a zinc oxide nanocolumn array on the seed layer. First, prepare the precursor solution by mixing zinc acetate dihydrate and hexamethylenetetramine in a 1:1 molar ratio, with deionized water as the solvent. Then, the silicon wafer with the zinc oxide seed layer is inverted at a 45-degree angle and immersed in the above-mentioned precursor solution, and the entire system is placed in a vacuum drying oven at 90 degrees Celsius for 4 hours of hydrothermal treatment, thereby growing a high-quality, regularly oriented zinc oxide nanocolumn array on the seed layer. Third step: performance optimization. Experiments show that by adjusting the concentration of the precursor solution, the spacing and crystallinity of the zinc oxide nanocolumn array can be precisely controlled. After comparative experiments using four concentrations of 0.01 mol / L, 0.025 mol / L, 0.05 mol / L, and 0.075 mol / L, it was found that when the solution concentration was 0.05 mol / L, the prepared ultraviolet detection chip had the best photoelectric response performance. This 3D nanocolumn structure has a larger specific surface area than traditional planar zinc oxide films, significantly increasing the light absorption path and photosensitive area, thereby increasing the detection sensitivity of the silicon wafer to 1 μw / cm 2 . Fourth step: post-processing. In order to further improve the performance and environmental stability of the nanocolumn array, post-processing is required. A protective film can be coated on the surface of the nanocolumns by chemical vapor deposition (CVD) to improve their environmental corrosion resistance. In addition, surface hydrogen passivation treatment can effectively reduce the surface defect state density of the nanocolumns, further improving their photoelectric performance and detection accuracy.

[0055] The ultraviolet detection chip prepared by the above method has a zinc oxide nanocolumn array that exhibits significant absorption characteristics in the ultraviolet wavelength range of 300 to 380 nanometers, which exactly covers the main ultraviolet radiation band generated by flame combustion, thereby achieving high selectivity and high sensitivity detection of flame signals, providing core device support for the high performance of the entire sensing system.

[0056] Finally, it is to be explained that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions, and all should be covered in the scope of the claims of the present application.

Claims

1. A mine-used flame sensor based on ultraviolet image sensing technology, characterized in that: The sensor comprises: a shell (1); an ultraviolet detection module (2) arranged in the shell (1), the ultraviolet detection module (2) comprising a photoelectric sensor of an ultraviolet detection chip composed of a zinc oxide nanocolumn array; a visible light imaging module (5) arranged on the shell (1) and used for capturing visible light band radiation characteristics of a flame; wherein the ultraviolet detection module (2) is used for acquiring an ultraviolet radiation signal of the flame, the visible light imaging module (5) is used for acquiring visible light image information of a shape, flicker frequency and spatial distribution of the flame, and the sensor fuses the ultraviolet radiation signal and the visible light image information to identify the flame.

2. The mine flame sensor based on ultraviolet image sensing technology according to claim 1, characterized in that: The ultraviolet detection chip is prepared by wafer-level 3D stacking of a heterogeneous sensor integration technology and based on a zinc oxide modified material.

3. A mine flame sensor based on ultraviolet image sensor technology according to claim 1 or 2, characterized in that: The photoelectric sensor further comprises a pixel circuit and a line control board; the ultraviolet detection chip is used for receiving a flame signal and converting the flame signal into an electric signal, the pixel circuit is used for amplifying and processing the electric signal, and the line control board is used for collecting and transmitting the processed electric signal.

4. The mine flame sensor based on ultraviolet image sensing technology according to claim 1, characterized in that: The visible light imaging module (5) is used for capturing a flame shape of diffusivity, smokelessness and a blue edge, a flicker frequency of 20-50 Hz, and spatial distribution and a motion trail of the flame.

5. The mine flame sensor based on ultraviolet image sensor technology according to claim 1, characterized in that: The zinc oxide nanocolumn array is prepared by first growing a zinc oxide film on a silicon wafer substrate and then growing a nanocolumn array on the zinc oxide film by a sol-gel method or a hydrothermal method.

6. The mine flame sensor based on ultraviolet image sensing technology according to claim 5, characterized in that: The spacing of the zinc oxide nanocolumn array is achieved by controlling the concentration of a precursor solution, wherein the photoelectric response performance is optimal when the concentration of the precursor solution is 0.05 mol / L.

7. The mine flame sensor based on ultraviolet image sensor technology according to claim 5, characterized in that: The zinc oxide nanocolumn array is subjected to a post-processing step, the post-processing step comprising introducing an anti-reflection layer by surface modification, coating a protective film by chemical vapor deposition (CVD), or performing surface hydrogen passivation treatment.

8. The mine flame sensor based on ultraviolet image sensor technology according to claim 1, characterized in that: The sensor further comprises a protective sleeve (3) arranged outside the visible light imaging module (5) and made of quartz glass or sapphire material.

9. The mine flame sensor based on ultraviolet image sensor technology according to claim 1, characterized in that: The sensor triggers an alarm only when the signals of the ultraviolet detection module (2) and the visible light imaging module (5) are determined to be abnormal synchronously.

10. The mine flame sensor based on ultraviolet image sensor technology according to claim 1, characterized in that: The shell (1) is provided with a connecting base (4) at the bottom for connecting an external tripod.

11. The mine flame sensor based on ultraviolet image sensor technology according to claim 1, characterized in that: The detection sensitivity of the ultraviolet detection module (2) is 1 μW / cm 2 Hereinafter, the response time is not more than 1 millisecond, and the effective detection distance is 1-50 meters.

12. The mine flame sensor based on ultraviolet image sensor technology according to claim 1, characterized in that: The sensor further comprises a processor used for time and space alignment and correlation analysis of the ultraviolet radiation signal and the visible light image information, and triggers an alarm only when the double-channel signals synchronously meet a preset flame characteristic model.

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