Portable methane visual imaging equipment with laser coupling camera

Abstract

The invention belongs to the technical field of methane laser detection, and particularly relates to methane visual imaging equipment of a portable laser coupling camera, which comprises a visual equipment main body and a lifting frame for supporting the visual equipment main body, the visual equipment main body comprises a gas detection ring, a first cover body, a second cover body, a servo motor, a methane laser detector and fan blades; according to the methane laser detector, the air knife and the air curtain which penetrate through the gas detection ring are generated on the basis of the fan blades, local air around the gas detection ring is stirred and guided more sufficiently, an old gas sample in the gas detection ring can be replaced with a new gas sample rapidly, the response time of the methane laser detector is shortened, monitoring and leakage early warning can be conducted in real time, and the detection efficiency is improved. The air flow can vertically and uniformly pass through the cross section of the whole gas detection ring through the air direction guided by the fan blades, so that each section of the infrared light beam can pass through a fresh gas sample driven by the air flow, and the corresponding relation between the light attenuation and the gas concentration is clearer and more sensitive.

Description

Technical Field

[0001] This invention belongs to the field of methane laser detection technology, specifically a methane visualization imaging device using a portable laser-coupled camera. Background Technology

[0002] Methane is a flammable gas, so it can explode when exposed to an open flame due to impurities. In mines or confined spaces, methane needs to be tested to prevent excessive concentrations from causing explosions that could threaten lives.

[0003] A Chinese patent with publication number CN116183540A discloses a methane gas laser detection device and its electrical control method, including a methane detector rotatably disposed in the middle of a gas detection ring, a gas pump connected to the bottom of the gas detection ring via a connecting cylinder, the gas pump and the gas detection ring forming an exhaust mechanism, a detector rotation motor connected to one side of the methane detector, the methane detector including a detector transmitter and a detector receiver, a convex lens disposed on the detector receiver, and a concave mirror and a wind speed sensor disposed on the inner side of the gas detection ring.

[0004] In the aforementioned prior art, a rotating methane detector, in conjunction with a gas detection ring, detects the gas passing through the gas detection ring and analyzes the location and concentration of methane. However, in the absence of wind, the airflow direction generated by the exhaust mechanism composed of the air pump and the gas detection ring is limited. At the same time, the airflow may be oblique, turbulent, or only pass through a local area of ​​the detection ring. This means that only part of the infrared beam passes through the area with the highest methane gas concentration, while other parts may pass through air with a lower methane concentration or undisturbed air. This makes the "average attenuation" signal received by the sensor unable to truly represent the methane concentration of the entire detection area. Current technology relies on air pumps and wind speed sensors. In windless conditions, the air pump needs to "extract" and "blow" low concentrations of methane from a distance through the detection loop. During this process, the air pump may mix methane with a large amount of air while drawing in ambient air, diluting the actual methane concentration entering the detection loop and causing a lower reading. Furthermore, without efficient and directional airflow, methane molecules diffuse slowly into the detection loop, potentially resulting in a detected concentration far lower than the actual concentration at the leak point.

[0005] Therefore, the present invention provides a methane visualization imaging device with a portable laser-coupled camera. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by the present invention to solve its technical problem is as follows: the portable laser coupling camera methane visualization imaging device of the present invention includes a visualization device body and a lifting frame for supporting the visualization device body; the visualization device body includes a gas detection ring, a first cover, a second cover, a servo motor, a methane laser detector and fan blades; The gas detection ring is fixed between the first cover and the second cover, and the second cover is rotatably connected to the lifting frame; the servo motor is fixed inside the first cover, and the output end of the servo motor is fixedly connected to an output shaft; the methane laser detector is located in the middle of the gas detection ring; the fan blade is located inside the second cover; one-way bearings are provided between the fan blade, the methane laser detector, and the output shaft; and when the servo motor switches directions, the methane laser detector and the fan blade alternately rotate with the output shaft.

[0008] Preferably, the one-way bearing includes an outer ring, a steering part, and a sliding unit. The steering part is fixedly connected to the output shaft and rotatably connected within the outer ring. The sliding unit is arranged between the steering part and the outer ring.

[0009] Preferably, the sliding unit includes a brake pad, a second spring, and a connecting part. A connecting rod is fixedly connected to the bottom of the brake pad, and the connecting rod is slidably connected in the connecting part. The second spring is sleeved on the connecting rod, and the two ends of the second spring abut against the surfaces of the brake pad and the connecting part, respectively. The outer periphery of the steering part is provided with a second arc-shaped part, and multiple second arc-shaped parts are provided in a circular array. The inner periphery of the outer ring is provided with a first arc-shaped part, and multiple first arc-shaped parts are provided in a circular array.

[0010] Preferably, the methane laser detector is provided with a transmitter and a receiver, and multiple transmitters and receivers are provided on the outer periphery of the methane laser detector, and the multiple transmitters and receivers are arranged alternately; a convex mirror is also fixedly connected to the receiver. A concave mirror is disposed inside the gas detection ring relative to the convex mirror.

[0011] Preferably, the fan blade is disposed inside the second cover, and an outer protective frame is fixedly connected to the outside of the second cover. A filter screen is disposed between the outer protective frame and the fan blade, and the filter screen is fixed to the second cover by screws.

[0012] Preferably, the second cover body is further provided with a cleaning rod, which is rotatably connected to the output shaft via a one-way bearing, and the cleaning rod is arranged between the outer protective frame and the filter screen. The cleaning rod is used to clean the surface of the filter screen.

[0013] Preferably, a snap-fit ​​shaft is fixedly connected to the outer periphery of the second cover body, and the second cover body is rotatably connected to the lifting frame via the snap-fit ​​shaft. A fixing shaft is fixedly connected to the outer periphery of the first cover body, and the lifting frame is provided with a first slot and a second slot. The fixing shaft engages with the first slot and the second slot.

[0014] Preferably, a fixed plate is fixedly connected to the lifting frame, and a locking plate is slidably connected to the lifting frame adjacent to the fixed plate. A limit rod is fixedly connected to one side of the locking plate, and the limit rod passes through the fixed plate. A first spring is sleeved on the limit rod, and the two ends of the first spring abut against the fixed plate and the locking plate. The bottom of the locking block is provided with an inclined surface. When the fixed shaft rotates to the first slot, the fixed shaft presses the inclined surface at the bottom of the locking block, causing the locking block to move upward and then return to its original position based on the first spring.

[0015] Preferably, a fixing frame is fixedly connected inside the first housing, and the servo motor is placed on the fixing frame. A clamp is fixedly connected to the fixing frame by screws, and the servo motor is fixedly connected to the first housing through the fixing frame and the clamp.

[0016] Preferably, a sliding rod is fixed to the side wall of the lifting frame, and an oblong groove is provided on the side wall of the locking plate. The locking plate is slidably connected to the lifting frame via the sliding rod, and the sliding rod passes through the oblong groove.

[0017] The beneficial effects of this invention are as follows: 1. The portable laser-coupled camera methane visualization imaging device of the present invention, by generating "wind knife" and "air curtain" through the gas detection ring based on fan blades, more fully agitates and guides the local air around the gas detection ring, can quickly push out the old gas sample in the gas detection ring and replace it with a new gas sample, shortens the response time of the methane laser detector, and enables real-time monitoring and leak warning. In addition, the wind direction guided by the fan blades can realize that the airflow passes through the entire cross-section of the gas detection ring vertically and uniformly, ensuring that each segment of the infrared beam can pass through the fresh gas sample carried by the airflow, making the correspondence between the light attenuation and the gas concentration clearer and more sensitive. 2. The portable laser-coupled camera methane visualization imaging device of the present invention achieves pulsed airflow and synchronous detection through a one-way bearing. Essentially, it prevents the fan blades from working continuously and instead switches to short-pulse start-up. During the interval when the fan blades are closed, the methane gas is allowed to diffuse naturally. At this time, the rotation scanning function of the methane laser detector is activated, and its original positioning capability is used to determine the direction of leakage. Then, the fan blade pulse is activated again for high-sensitivity concentration confirmation. Based on this "static-dynamic" combined mode, the location and quantification of methane leakage are achieved, enabling the methane laser detector to detect methane leakage and locate the leakage point in a timely manner even in the context of low methane concentration. Attached Figure Description

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a perspective view of the present invention; Figure 2 This is a front view of the present invention; Figure 3 yes Figure 2 Sectional view at point AA; Figure 4 This is a state diagram of the main body of the visualization device after rotation in this invention; Figure 5 This is a rear view of the present invention; Figure 6 This is a diagram showing the fit between the fan blade, one-way bearing, methane laser detector, and output shaft in this invention. Figure 7 This is a schematic diagram of the one-way bearing in this invention; Figure 8 This is a three-dimensional view of the main body of the visualization device in this invention.

[0020] In the diagram: 1. First cover; 11. Fixed shaft; 12. Fixed frame; 13. Clamp; 2. Lifting frame; 21. Fixed plate; 22. Locking plate; 221. Limiting rod; 23. First spring; 24. Slide rod; 26. First slot; 27. Second slot; 3. Servo motor; 31. Output shaft; 4. Second cover; 41. Outer protective frame; 42. Filter screen; 43. Snap-fit ​​shaft; 5. Gas detection ring; 6. Cleaning rod; 7. Fan blade; 8. Methane laser detector; 81. Transmitter; 82. Receiver; 821. Convex mirror; 9. One-way bearing; 91. Outer ring; 911. First arc-shaped part; 92. Turning part; 921. Second arc-shaped part; 941. Brake pad; 942. Second spring; 943. Connecting part. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0022] like Figures 1 to 8 As shown in the figure, the portable laser-coupled camera methane visualization imaging device of the present invention includes a visualization device body and a lifting frame 2 for supporting the visualization device body; the visualization device body includes a gas detection ring 5, a first cover 1, a second cover 4, a servo motor 3, a methane laser detector 8 and a fan blade 7; The gas detection ring 5 is fixed between the first cover 1 and the second cover 4, and the second cover 4 is rotatably connected to the lifting frame 2; the servo motor 3 is fixed inside the first cover 1, and the output end of the servo motor 3 is fixedly connected to the output shaft 31; the methane laser detector is located in the middle of the gas detection ring 5; the fan blade 7 is located inside the second cover 4; a one-way bearing 9 is provided between the fan blade 7, the methane laser detector 8 and the output shaft 31; and when the servo motor 3 switches directions, the methane laser detector 8 and the fan blade 7 alternately follow the output shaft 31 to rotate.

[0023] In windless conditions, the air pump needs to "extract" and "blow" low-concentration methane from a distance through the detection loop. During this process, the air pump may mix methane with a large amount of air while drawing in ambient air, diluting the actual methane concentration entering the detection loop and resulting in a lower reading. Furthermore, without efficient and directional airflow, methane molecules diffuse slowly into the detection loop, potentially leading to a detected concentration far lower than the actual concentration at the leak point. Based on the above, in one embodiment of the present invention, when detecting methane leaks, the main body of the visualization device and the carrying rack 2 allow for handheld operation by the testing personnel, thus demonstrating portability. In the process of identifying and detecting methane, a fan-shaped airflow is used... The blade 7 generates a "wind knife" and "air curtain" that penetrate the gas detection ring 5, which more fully agitates and guides the local air around the gas detection ring 5. This can quickly push out the old gas sample in the gas detection ring 5 and replace it with a new gas sample, shortening the response time of the methane laser detector 8. It can monitor and provide early warning of leaks in real time. In addition, the wind direction guided by the blade 7 can make the airflow pass through the entire cross-section of the gas detection ring 5 vertically and evenly, ensuring that every segment of the infrared beam can pass through the fresh gas sample carried by the airflow, making the correspondence between the light attenuation and the gas concentration clearer and more sensitive. It is worth noting that the efficient airflow guidance achieved by the fan blade 7 in this application leads to a more concentrated and faster "delivery" of methane escaping from the leak point into the gas detection ring 5. The methane concentration read by the methane laser detector is a peak or average concentration in a local area within the gas detection ring 5, which may be higher than the concentration measured under natural diffusion. Therefore, from the perspective of "detecting methane leaks," the airflow guidance formed by the fan blade 7 improves the detection capability for minor leaks, lowers the detection limit, and makes the alarm for methane leak detection more timely. From the perspective of "quantitative analysis," since the reading output by the methane laser detector 8 includes not only the environmental background concentration but also the methane concentration enhancement effect caused by gas disturbance, it indicates that the airflow generated by the fan blade 7 will disturb... The natural concentration gradient distribution near the leak point means that, under natural diffusion, the point with the highest concentration is usually closest to the leak source. However, strong airflow can "blow away" methane, causing it to diffuse downwind. This means that the location with the highest sensor reading may not be the leak point itself, but rather a location along the airflow path. Based on the above, this application uses a one-way bearing 9 to achieve pulsed airflow and synchronous detection. Essentially, this means not allowing the fan blade 7 to work continuously, but instead switching to short-pulse start-up. During the interval when the fan blade 7 is closed, the methane gas is allowed to diffuse naturally. At this time, the rotation scanning function of the methane laser detector 8 is activated, using its original positioning capability to determine the direction of the leak. Then, the fan blade 7 is pulsed again for high-sensitivity concentration confirmation. Based on this "static-dynamic" combined mode, the location and quantification of methane leaks can be achieved. It is worth noting that the one-way bearing 9 in this application is installed between the fan blade 7, the methane laser detector 8, and the output shaft 31. The function of the one-way bearing 9 is to enable the alternating operation of the fan blade 7 and the methane laser detector 8 when the output shaft 31 outputs power. Simply put, when the fan blade 7 needs to generate directional airflow guidance, the methane laser detector 8 does not rotate to scan. When the old gas sample in the gas detection ring 5 is removed and a fresh gas sample enters the gas detection ring 5, the methane laser detector 8 is then controlled to rotate to scan based on the servo motor 3. At this time, the fan blade 7 stops rotating. Based on this, the above-mentioned pulsed airflow and synchronous detection can be achieved. Based on the short pulse start of the fan blade 7, the methane laser detector 8 in this embodiment can detect methane leaks and locate the methane leak point in a timely manner in the background of low concentration of methane leaks. The main body of the visualization device mentioned in this application also includes a display screen (not shown in the figure). Based on the analysis and conversion of the attenuation of infrared light by the methane laser detector 8, i.e., the main controller, the results and methane concentration and location are displayed on the display screen to achieve visualization.

[0024] like Figure 7As shown, the one-way bearing 9 includes an outer ring 91, a steering part 92, and a sliding unit. The steering part 92 is fixedly connected to the output shaft 31 and is rotatably connected inside the outer ring 91. The sliding unit is arranged between the steering part 92 and the outer ring 91.

[0025] like Figures 1 to 7 As shown, the sliding unit includes a brake pad 941, a second spring 942, and a connecting part 943. A connecting rod is fixedly connected to the bottom of the brake pad 941, and the connecting rod is slidably connected in the connecting part 943. The second spring 942 is sleeved on the connecting rod, and the two ends of the second spring 942 abut against the surfaces of the brake pad 941 and the connecting part 943, respectively. The outer periphery of the steering part 92 is provided with a second arc-shaped part 921, and multiple second arc-shaped parts 921 are provided in a circular array. The inner periphery of the outer ring 91 is provided with a first arc-shaped part 911, and multiple first arc-shaped parts 911 are provided in a circular array.

[0026] In one embodiment of this application, the one-way bearing 9 connects the output shaft 31 with the fan blade 7 and the methane laser detector 8, and ensures that when the output shaft 31 rotates in either direction, only the fan blade 7 or the methane laser detector 8 operates independently. Figure 8As shown, when the one-way bearing 9 rotates clockwise with the output shaft 31, the output shaft 31 drives the steering part 92 to rotate. Since the sliding unit is arranged between the steering part 92 and the outer ring 91, when the steering part 92 rotates, it will "wrap" the sliding unit and rotate together with the steering part 92 within the outer ring 91. During this process, the second arc-shaped part 921 on the steering part 92 will squeeze the sliding unit, causing the sliding unit to slide between the outer ring 91 and the steering part 92. And when the sliding unit approaches the first arc-shaped part 921... At position 11, considering that the first arc-shaped portion 911 may compress the sliding unit, the second spring 942 inside the sliding unit will compress to allow the sliding unit to pass over the first arc-shaped portion 911, so that the outer ring 91 does not rotate synchronously with the steering portion 92. Conversely, when the output shaft 31 rotates counterclockwise, the steering portion 92 no longer "encloses" the sliding unit's displacement, but the second arc-shaped portion 921 on the steering portion 92 will compress the sliding unit, which may exert pressure on the sliding unit based on the second arc-shaped portion 921. Applying lateral pressure causes the sliding unit to produce a small displacement. However, under the action of the first arc-shaped part 911, the sliding unit is also intercepted. When the "tip" of the second arc-shaped part 921 corresponds to the "tip" of the first arc-shaped part 911, the second spring 942 inside the sliding unit will be compressed to the extreme. At this time, because the first arc-shaped part 911 will intercept the sliding unit, and in conjunction with the brake pad 941 inside the braking unit, the outer ring 91 will rotate synchronously with the output shaft 31. Based on the above, the output shaft 31 is set to be completely opposite to the direction of the fan blade 7 and the methane laser detector 8. This allows the fan blade 7 and the methane laser detector 8 to alternate when the output shaft 31 is outputting. This satisfies the requirement that when the fan blade 7 rotates and generates a directional airflow, the methane laser detector 8 does not perform a rotational scan. However, when the directional airflow passes through the gas detection ring 5, the fan blade 7 stops, and the methane laser detector 8 performs a rotational scan. This enables high-sensitivity concentration confirmation. Based on the "static-dynamic" combined mode, the location and quantification of methane leakage can be achieved.

[0027] like Figures 1 to 7 As shown, the methane laser detector 8 is provided with a transmitter 81 and a receiver 82. Multiple transmitters 81 and receivers 82 are provided on the outer periphery of the methane laser detector 8, and the multiple transmitters 81 and receivers 82 are arranged alternately. A convex mirror 821 is also fixedly connected to the receiver 82. A concave mirror is provided inside the gas detection ring 5 relative to the convex mirror 821.

[0028] In one embodiment of the present invention, the methane leak is located and quantified based on the activation method of the dynamic-static combined methane laser detector 8 and the fan blade 7. The principle is explained in detail below: Phase 1: Static scanning period (servo power drives methane laser detector 8 to rotate) — The core objective is "positioning". During this phase, the lateral fan blades 7 stop working, the airflow inside the gas detection ring 5 becomes calm, and the methane gas relies on natural diffusion. Data acquisition: The methane laser detector 8 rotates slowly under the drive of the servo motor 3. The transmitting end 81 emits infrared lasers to the concave mirrors in various directions, and the receiving end 82 continuously records the light intensity attenuation data at different angles. Location determination logic: Due to the slow natural diffusion speed of gas, a relatively high concentration of "gas cloud" will form near the leak point. When the laser path of the rotating methane laser detection sweeps across this gas cloud, a signal peak will be detected.

[0029] Meanwhile, the main controller (not shown in the figure) can deduce the direction of the methane gas cloud source by analyzing the angle at which the signal peak appears within a complete rotation cycle. For example, if the signal is strongest when rotating to the northwest direction, the leak point is likely to be in the northwest direction of the equipment. The main controller is a processor that processes the relationship between infrared laser attenuation and methane gas concentration, which is existing technology and will not be described in detail here. The concentration measured at this stage is the concentration after diffusion and dilution. Since there is no active sampling, its value may be low, but it reflects the natural distribution of the gas in space and is a key basis for location.

[0030] Phase Two: Active Airflow Period (Servo Motor 3 drives Fan Blade 7) — The core objective is "quantitative" control; After initially determining the direction of the leak through Phase 1, the air inlet of fan blade 7 can be adjusted to face that direction (such as the northwest direction mentioned above), and then a short pulse airflow can be started. Data acquisition: The fan blade 7 rotates at high speed, generating a directional airflow that directly "captures" the "fresh" methane gas released from the suspected leak point and blows it through the laser path in the gas detection ring 5. At this time, the methane laser detector 8 temporarily stops rotating, fixes itself to the concave mirror, and performs high-speed, continuous data acquisition.

[0031] Concentration quantification logic: The active airflow delivers the gas sample, which has not been diluted by long-distance diffusion, directly to the detection point. Therefore, the detector will receive a higher and sharper concentration signal pulse at this stage. Since the reading at this time is not the average concentration of the environment, but the instantaneous concentration in the sampled airflow, the algorithm of the main controller needs to combine the known fan blade speed, airflow cross-sectional area and the detected peak concentration to perform integral calculations and finally calculate the leakage rate (e.g., the mass of methane leaked per unit time, such as g / s).

[0032] Leakage rate is a more engineering-significant indicator than static volume concentration, as it directly reflects the severity of the leak and facilitates risk assessment and maintenance prioritization.

[0033] Based on the above, a hierarchical answer can be given through the cyclical combination of the two stages: First, define the leak location: The initial location is directly provided by Phase 1 (static scan), and the output result is "the leak source is located in the direction of the equipment [angle]". It is used for preliminary investigation of large areas. Precise positioning, combined with the movement of the equipment itself, involves repeatedly changing the equipment position and repeating the above "dynamic and static" detection cycle. By using triangulation or signal strength change trends, the range can be further narrowed down, and the specific location of the leak point can be determined. Define methane concentration / leakage: Environmental reference concentration: The concentration value measured in Phase 1 (static scan) can be used as a reference for methane concentration in the environmental context of the area. It reflects the methane level at the location without active intervention.

[0034] Actual leakage intensity: The leakage rate (mass flow rate) calculated in Phase 2 (active airflow) is defined as the "actual concentration" index for assessing the severity of the leakage. Based on this index, it is directly related to the physical characteristics of the leak point and excludes the influence of environmental diffusion.

[0035] In summary, based on the "dynamic-static combined" pulse detection method, a complete definition of methane leakage is achieved through a multi-step, intelligent process. The initial determination is made from the signal peak angle during the static scanning period, which can be combined with motion monitoring for precise location. Then, the leakage rate is accurately quantified by calculating the instantaneous peak concentration during the active airflow period after correction for parameters such as wind speed and cross-sectional area. The concentration during the static scanning period is used as an environmental reference. Based on this, the advantages of rotating scanning and airflow control are fully utilized. Furthermore, through time-division multiplexing and data fusion, the potential contradiction between sensitivity and location capability is resolved, ultimately achieving rapid, accurate, and precise detection of methane leaks. Reliable detection and evaluation; wherein, the output shaft 31 controls the fan blade 7 and the methane laser detector 8 to rotate at different speeds. It is understandable that the fan blade 7 needs to rotate at high speed when starting up to quickly form airflow guidance, while the methane laser detector 8 does not need to be too fast when rotating and scanning. Therefore, a reduction gear set can be added to design different transmission ratios for the fan blade 7 and the methane laser detector 8. For example, a high speed ratio can be set for the fan blade 7 to ensure that sufficient airflow can be generated when the servo motor 3 is running at medium speed, and a low speed ratio can be set for the methane laser detector 8 so that even if the servo motor 3 is in full reverse rotation, the methane laser detector 8 can scan slowly, thereby improving positioning accuracy.

[0036] like Figures 1 to 5 , Figure 8 As shown, the fan blade 7 is disposed inside the second cover 4, and an outer protective frame 41 is fixedly connected to the outside of the second cover 4. A filter screen 42 is disposed between the outer protective frame 41 and the fan blade 7, and the filter screen 42 is fixedly connected to the second cover 4 by screws.

[0037] In this embodiment, due to the lateral directional airflow achieved based on fan blade 7 in this application, such as Figures 4 to 5 The dashed arrows shown may indicate that impurities such as leaves carried in the lateral airflow may enter the gas detection ring 5. In this application, when infrared light is emitted from the emitting end 81 of the methane laser detector 8, the infrared light may be absorbed by leaves, resulting in additional attenuation of the infrared light. Based on this, a filter 42 is also provided outside the second cover 4 in this application. When the fan blades 7 are activated to form a lateral airflow, impurities such as leaves carried in the lateral airflow will be blocked outside the filter 42, thereby reducing the impurities in the airflow passing through the gas detection ring 5, reducing the additional attenuation of the infrared light, and making the infrared light attenuation obtained by the test closer to reality. The solid arrows shown in Figure 5 indicate the rotation direction of the main body of the visualization device. It is worth noting that the emitter 81 of the methane laser detector 8 selects the specific absorption peak of methane molecules (such as 1653nm or 3.3μm). However, many organic materials (such as cellulose in leaves, water, and certain plastics) also have absorption characteristics in a broad infrared band. If the absorption spectrum of the impurity overlaps with the absorption peak of methane, when the impurity passes through the optical path, it will cause non-methane absorption attenuation of the infrared light. Therefore, the receiver 82 will mistakenly judge that this attenuation is caused by methane, thus generating a brief, high-concentration "false positive" alarm signal. When an opaque or semi-transparent... When impurities (such as leaves or large dust particles) happen to pass through the laser emission path, they will partially or completely block the light path. If infrared light shines on the leaves, due to the rough surface of the leaves, diffuse reflection will occur instead of specular reflection. Only a very small amount of light will be reflected back to the concave mirror and receiver 82 along the original path, causing the signal received by receiver 82 to be drastically attenuated or even reduced to zero. This may lead to the judgment that the light path is severely blocked or that the equipment is malfunctioning. More importantly, at the moment of blockage, the detection function actually fails, resulting in data loss. If there happens to be a methane leak at this time, it will lead to a false negative.

[0038] like Figures 1 to 5 , Figure 8 As shown, a cleaning rod 6 is also provided inside the second cover 4. The cleaning rod 6 is rotatably connected to the output shaft 31 via a one-way bearing 9, and the cleaning rod 6 is arranged between the outer protective frame 41 and the filter screen 42. The cleaning rod 6 is used to clean the surface of the filter screen 42.

[0039] It is understandable that the lateral airflow generated by the fan blade 7 will cause impurities to be trapped on the outside of the filter screen 42. After long-term use, impurities will accumulate on the surface of the filter screen 42. Therefore, in this application, the surface of the filter screen 42 can also be cleaned based on the cleaning rod 6. It is worth noting that the cleaning rod 6 can operate synchronously with the fan blade 7. That is to say, the cleaning rod 6 is also connected to the output shaft 31 via the one-way bearing 9, and the one-way bearing 9 of the cleaning rod 6 and the output shaft 31 are arranged in the same direction as the one-way bearing 9 of the fan blade 7 and the output shaft 31.

[0040] like Figures 1 to 4 , Figure 8 As shown, the second cover 4 is fixedly connected to the outer periphery of the second cover 4, and the second cover 4 is rotatably connected to the lifting frame 2 via the snap-fit ​​shaft 43. The first cover 1 is fixedly connected to the outer periphery of the first cover 1, and the lifting frame 2 is provided with a first slot 26 and a second slot 27. The fixed shaft 11 is engaged with the first slot 26 and the second slot 27.

[0041] When detecting methane concentration in the environment, methane diffuses upwards. Therefore, if the main body of the visualization device is parallel to the ground, the methane leak point may be difficult to locate. To address this, this application allows the visualization device to be positioned relative to the ground. When it is necessary to control the main body of the visualization device relative to the ground, the main body of the visualization device can be manually rotated so that the fan blade 7 is relative to the ground. After the main body of the visualization device is rotated, it can be positioned by engaging the fixed shaft 11 in the first slot 26. Correspondingly, when the main body of the visualization device is parallel to the ground, it can also be positioned by engaging the fixed shaft 11 in the second slot 27. Based on this, when the methane leak point is difficult to detect, it may be because the height of the methane leak is not high enough to be detected. In this case, by changing the direction of the main body of the visualization device so that the fan blade 7 is relative to the ground, the methane leak point can be located, thereby enabling the location of the methane leak point that has just begun to escape.

[0042] like Figures 1 to 4 , Figure 8 As shown, a fixed plate 21 is fixedly connected to the lifting frame 2, and a locking plate 22 is slidably connected to the lifting frame 2 adjacent to the fixed plate 21. A limiting rod 221 is fixedly connected to one side of the locking plate 22, and the limiting rod 221 passes through the fixed plate 21. A first spring 23 is sleeved on the limiting rod 221, and the two ends of the first spring 23 abut against the fixed plate 21 and the locking plate 22. The bottom of the locking block is provided with an inclined surface. When the fixed shaft 11 rotates to the first slot 26, the fixed shaft 11 presses the inclined surface at the bottom of the locking block, causing the locking block to move upward and then return to its original position based on the first spring 23.

[0043] When the fan blades 7 in the main body of the visualization device are relative to the ground, the main body of the visualization device needs to be positioned. In one embodiment of the present invention, after the main body of the visualization device is manually rotated, the fixed shaft 11 on its second cover 4 will disengage from the second slot 27 and be inserted into the first slot 26 after rotation. In order to enable the main body of the visualization device to maintain the posture of the fan blades 7 relative to the ground for a long time, in this embodiment, when the fixed shaft 11 is about to be inserted into the first slot 26, the fixed shaft 11 will press the inclined surface at the bottom of the locking plate 22, and cause the locking plate 22 to slide upward on the side wall of the lifting frame 2 until the fixed shaft 11 is fully inserted into the first slot 26. In the first slot 26, as the fixed shaft 11 presses against the locking plate 22 and causes the locking plate 22 to move upward, the first spring 23 at the top of the locking plate 22 is compressed and generates elastic potential energy. Subsequently, when the fixed shaft 11 is fully inserted into the first slot 26, the first spring 23 is released, and the locking plate 22 is driven to reset downward based on the elastic force, so that the first slot 26 is closed. At this time, the fixed shaft 11 is limited in the first slot 26. Based on the cooperation between the locking plate 22 and the first slot 26, the main body of the visualization device after changing its posture is limited, so that the fan blade 7 is relative to the ground, thereby making it easier to detect the methane leak point that has just started to leak.

[0044] like Figures 1 to 8 As shown, a fixing frame 12 is fixedly connected inside the first cover 1, and the servo motor 3 is placed on the fixing frame 12. A clamp 13 is fixedly connected to the fixing frame 12 by screws. The servo motor 3 is fixed inside the first cover 1 via the fixing frame 12 and the clamp 13.

[0045] like Figures 1 to 4 As shown, a sliding rod 24 is fixedly connected to the side wall of the lifting frame 2, and an oblong groove is provided on the side wall of the locking plate 22. The locking plate 22 is slidably connected to the lifting frame 2 via the sliding rod 24, and the sliding rod 24 passes through the oblong groove.

[0046] Working principle: When detecting methane leaks, the main body of the visualization device and the carrying frame 2 allow for hand-carrying by the testing personnel, thus demonstrating portability. During the identification and detection of methane, the fan blades 7 generate "air knives" and "air curtains" that penetrate the gas detection ring 5, more fully agitating and guiding the local air around the gas detection ring 5. This can quickly push out the old gas sample in the gas detection ring 5 and replace it with a new gas sample, shortening the response time of the methane laser detector 8. It can perform real-time monitoring and leak warning. In addition, the airflow guided by the fan blades 7 can achieve vertical and uniform airflow through the entire cross-section of the gas detection ring 5, ensuring that every segment of the infrared beam can pass through the fresh gas sample carried by the airflow, making the correspondence between the light attenuation and the gas concentration clearer and more sensitive. It is worth noting that the efficient airflow guidance achieved by the fan blade 7 in this application leads to a more concentrated and faster "delivery" of methane escaping from the leak point into the gas detection ring 5. The methane concentration read by the methane laser detector is a peak or average concentration in a local area within the gas detection ring 5, which may be higher than the concentration measured under natural diffusion. Therefore, from the perspective of "detecting methane leaks," the airflow guidance formed by the fan blade 7 improves the detection capability for minor leaks, lowers the detection limit, and makes the alarm for methane leak detection more timely. From the perspective of "quantitative analysis," since the reading output by the methane laser detector 8 includes not only the environmental background concentration but also the methane concentration enhancement effect caused by gas disturbance, it indicates that the airflow generated by the fan blade 7 will disturb... The natural concentration gradient distribution near the leak point means that, under natural diffusion, the point with the highest concentration is usually closest to the leak source. However, strong airflow can "blow away" methane, causing it to diffuse downwind. This means that the location with the highest sensor reading may not be the leak point itself, but rather a location along the airflow path. Based on the above, this application uses a one-way bearing 9 to achieve pulsed airflow and synchronous detection. Essentially, this means not allowing the fan blade 7 to work continuously, but instead switching to short-pulse start-up. During the interval when the fan blade 7 is closed, the methane gas is allowed to diffuse naturally. At this time, the rotation scanning function of the methane laser detector 8 is activated, using its original positioning capability to determine the direction of the leak. Then, the fan blade 7 is pulsed again for high-sensitivity concentration confirmation. Based on this "static-dynamic" combined mode, the location and quantification of methane leaks can be achieved. It is worth noting that the one-way bearing 9 in this application is installed between the fan blade 7, the methane laser detector 8 and the output shaft 31. The function of the one-way bearing 9 is to realize the alternating action of the fan blade 7 and the methane laser detector 8 when the output shaft 31 outputs power. Simply put, when the fan blade 7 needs to generate directional airflow guidance, the methane laser detector 8 does not rotate to scan. When the old gas sample in the gas detection ring 5 is removed and a fresh gas sample enters the gas detection ring 5, the methane laser detector 8 is rotated to scan based on the servo motor 3. At this time, the fan blade 7 stops rotating. Based on this, the above-mentioned pulsed airflow and synchronous detection can be realized. Based on the short pulse start of the fan blade 7, the methane laser detector 8 in this embodiment can detect methane leakage and locate the methane leakage point in a timely manner in the background of low concentration of methane leakage. When the one-way bearing 9 rotates clockwise with the output shaft 31, the output shaft 31 drives the steering part 92 to rotate. Since the sliding unit is arranged between the steering part 92 and the outer ring 91, when the steering part 92 rotates, it will "wrap" the sliding unit and rotate it together with the steering part 92 within the outer ring 91. During this process, the second arc-shaped part 921 on the steering part 92 will squeeze the sliding unit, causing the sliding unit to slide between the outer ring 91 and the steering part 92 with the steering part 92. And when the sliding unit approaches the first arc-shaped part 911... When positioning, considering that the first arc-shaped portion 911 may compress the sliding unit, the second spring 942 inside the sliding unit will compress to allow the sliding unit to pass over the first arc-shaped portion 911, so that the outer ring 91 does not rotate synchronously with the steering portion 92. Conversely, when the output shaft 31 rotates counterclockwise, the steering portion 92 no longer "encloses" the sliding unit's displacement, but the second arc-shaped portion 921 on the steering portion 92 will compress the sliding unit, which may apply lateral pressure to the sliding unit based on the second arc-shaped portion 921. The pressure causes the sliding unit to produce a small displacement, but under the action of the first arc-shaped part 911, the sliding unit will also be intercepted. When the "tip" of the second arc-shaped part 921 corresponds to the "tip" of the first arc-shaped part 911, the second spring 942 in the sliding unit will be compressed to the extreme. At this time, because the first arc-shaped part 911 will intercept the sliding unit, and in conjunction with the brake pad 941 in the braking unit, the outer ring 91 will rotate synchronously with the output shaft 31. Based on the above, the output shaft 31 is set to be completely opposite to the direction of the fan blade 7 and the methane laser detector 8. This allows the fan blade 7 and the methane laser detector 8 to alternate when the output shaft 31 is outputting. This satisfies the requirement that when the fan blade 7 rotates and generates a directional airflow, the methane laser detector 8 does not perform a rotational scan. However, when the directional airflow passes through the gas detection ring 5, the fan blade 7 stops, and the methane laser detector 8 performs a rotational scan. This enables high-sensitivity concentration confirmation. Based on the "static-dynamic" combined mode, the location and quantification of methane leakage can be achieved.

[0047] Based on the combined static and dynamic activation method of the methane laser detector 8 and the fan blade 7, the location and quantification of methane leaks are achieved. The principle is explained in detail below: Phase 1: Static scanning period (servo power drives methane laser detector 8 to rotate) — The core objective is "positioning". During this phase, the lateral fan blades 7 stop working, the airflow inside the gas detection ring 5 becomes calm, and the methane gas relies on natural diffusion. Data acquisition: The methane laser detector 8 rotates slowly under the drive of the servo motor 3. The transmitting end 81 emits infrared lasers to the concave mirrors in various directions, and the receiving end 82 continuously records the light intensity attenuation data at different angles. Location determination logic: Due to the slow natural diffusion speed of gas, a relatively high concentration of "gas cloud" will form near the leak point. When the laser path of the rotating methane laser detection sweeps across this gas cloud, a signal peak will be detected.

[0048] Meanwhile, the main controller (not shown in the figure) can deduce the direction of the methane gas cloud source by analyzing the angle at which the signal peak appears within a complete rotation cycle. For example, if the signal is strongest when rotating to the northwest direction, the leak point is likely to be in the northwest direction of the equipment. The main controller is a processor that processes the relationship between infrared laser attenuation and methane gas concentration, which is existing technology and will not be described in detail here. The concentration measured at this stage is the concentration after diffusion and dilution. Since there is no active sampling, its value may be low, but it reflects the natural distribution of the gas in space and is a key basis for location.

[0049] Phase Two: Active Airflow Period (Servo Motor 3 drives Fan Blade 7) — The core objective is "quantitative" control; After initially determining the direction of the leak through Phase 1, the air inlet of fan blade 7 can be adjusted to face that direction (such as the northwest direction mentioned above), and then a short pulse airflow can be started. Data acquisition: The fan blade 7 rotates at high speed, generating a directional airflow that directly "captures" the "fresh" methane gas released from the suspected leak point and blows it through the laser path in the gas detection ring 5. At this time, the methane laser detector 8 temporarily stops rotating, fixes itself to the concave mirror, and performs high-speed, continuous data acquisition.

[0050] Concentration quantification logic: The active airflow delivers the gas sample, which has not been diluted by long-distance diffusion, directly to the detection point. Therefore, the detector will receive a higher and sharper concentration signal pulse at this stage. Since the reading at this time is not the average concentration of the environment, but the instantaneous concentration in the sampled airflow, the algorithm of the main controller needs to combine the known fan blade speed, airflow cross-sectional area and the detected peak concentration to perform integral calculations and finally calculate the leakage rate (e.g., the mass of methane leaked per unit time, such as g / s).

[0051] Leakage rate is a more engineering-significant indicator than static volume concentration, as it directly reflects the severity of the leak and facilitates risk assessment and maintenance prioritization.

[0052] Based on the above, a hierarchical answer can be given through the cyclical combination of the two stages: First, define the leak location: The initial location is directly provided by Phase 1 (static scan), and the output result is "the leak source is located in the direction of the equipment [angle]". It is used for preliminary investigation of large areas. Precise positioning, combined with the movement of the equipment itself, involves repeatedly changing the equipment position and repeating the above "dynamic and static" detection cycle. By using triangulation or signal strength change trends, the range can be further narrowed down, and the specific location of the leak point can be determined. Define methane concentration / leakage: Environmental reference concentration: The concentration value measured in Phase 1 (static scan) can be used as a reference for methane concentration in the environmental context of the area. It reflects the methane level at the location without active intervention.

[0053] Actual leakage intensity: The leakage rate (mass flow rate) calculated in Phase 2 (active airflow) is defined as the "actual concentration" index for assessing the severity of the leakage. Based on this index, it is directly related to the physical characteristics of the leak point and excludes the influence of environmental diffusion.

[0054] In summary, based on the "dynamic-static combined" pulse detection method, a complete definition of methane leakage is achieved through a multi-step, intelligent process. The initial determination is made from the signal peak angle during the static scanning period, which can be combined with motion monitoring for precise location. Then, the leakage rate is accurately quantified by calculating the instantaneous peak concentration during the active airflow period after correction for parameters such as wind speed and cross-sectional area. The concentration during the static scanning period is used as an environmental reference. Based on this, the advantages of rotating scanning and airflow control are fully utilized. Furthermore, through time-division multiplexing and data fusion, the potential contradiction between sensitivity and location capability is resolved, ultimately achieving rapid, accurate, and precise detection of methane leaks. Reliable detection and evaluation; wherein, the output shaft 31 controls the fan blade 7 and the methane laser detector 8 to rotate at different speeds. It is understandable that the fan blade 7 needs to rotate at high speed when starting up to quickly form airflow guidance, while the methane laser detector 8 does not need to be too fast when rotating and scanning. Therefore, a reduction gear set can be added to design different transmission ratios for the fan blade 7 and the methane laser detector 8. For example, a high speed ratio can be set for the fan blade 7 to ensure that sufficient airflow can be generated when the servo motor 3 is running at medium speed, and a low speed ratio can be set for the methane laser detector 8 so that even if the servo motor 3 is in full reverse rotation, the methane laser detector 8 can scan slowly, thereby improving positioning accuracy.

[0055] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A portable laser-coupled camera-based methane visualization imaging device, characterized in that: It includes a main body of visualization equipment and a lifting frame (2) for supporting the main body of visualization equipment; the main body of visualization equipment includes a gas detection ring (5), a first cover (1), a second cover (4), a servo motor (3), a methane laser detector (8), and fan blades (7); The gas detection ring (5) is fixed between the first cover (1) and the second cover (4), and the second cover (4) is rotatably connected to the lifting frame (2); the servo motor (3) is fixed inside the first cover (1), and the output end of the servo motor (3) is fixed with an output shaft (31); the methane laser detector is located in the middle of the gas detection ring (5); the fan blade (7) is located inside the second cover (4); a one-way bearing (9) is provided between the fan blade (7), the methane laser detector (8) and the output shaft (31); and when the servo motor (3) switches directions, the methane laser detector (8) and the fan blade (7) alternately follow the output shaft (31) to rotate.

2. The methane visualization imaging device with a portable laser-coupled camera according to claim 1, characterized in that: The one-way bearing (9) includes an outer ring (91), a steering part (92) and a sliding unit. The steering part (92) is fixedly connected to the output shaft (31) and is rotatably connected inside the outer ring (91). The sliding unit is arranged between the steering part (92) and the outer ring (91).

3. The methane visualization imaging device with a portable laser-coupled camera according to claim 2, characterized in that: The sliding unit includes a brake pad (941), a second spring (942), and a connecting part (943). A connecting rod is fixedly connected to the bottom of the brake pad (941), and the connecting rod is slidably connected in the connecting part (943). The second spring (942) is sleeved on the connecting rod, and the two ends of the second spring (942) abut against the surfaces of the brake pad (941) and the connecting part (943), respectively. The outer periphery of the steering part (92) is provided with a second arc-shaped part (921), and multiple second arc-shaped parts (921) are provided in a circular array. The inner periphery of the outer ring (91) is provided with a first arc-shaped part (911), and multiple first arc-shaped parts (911) are provided in a circular array.

4. The methane visualization imaging device with a portable laser-coupled camera according to claim 1, characterized in that: The methane laser detector (8) is provided with a transmitter (81) and a receiver (82). Multiple transmitters (81) and receivers (82) are provided on the outer periphery of the methane laser detector (8), and the multiple transmitters (81) and receivers (82) are arranged alternately. A convex mirror (821) is also fixed on the receiver (82). A concave mirror is provided inside the gas detection ring (5) relative to the convex mirror (821).

5. The methane visualization imaging device with a portable laser-coupled camera according to claim 1, characterized in that: The fan blade (7) is located inside the second cover (4). An outer protective frame (41) is fixed to the outside of the second cover (4). A filter screen (42) is provided between the outer protective frame (41) and the fan blade (7). The filter screen (42) is fixed to the second cover (4) by screws.

6. The methane visualization imaging device with a portable laser-coupled camera according to claim 1, characterized in that: The second cover (4) is also provided with a cleaning rod (6), which is rotatably connected to the output shaft (31) via a one-way bearing (9), and the cleaning rod (6) is arranged between the outer protective frame (41) and the filter screen (42). The cleaning rod (6) is used to clean the surface of the filter screen (42).

7. The methane visualization imaging device with a portable laser-coupled camera according to claim 1, characterized in that: The second cover (4) is fixedly connected to the outer periphery of the second cover (4), and the second cover (4) is rotatably connected to the lifting frame (2) via the locking shaft (43). The first cover (1) is fixedly connected to the outer periphery of the first cover (1), and the lifting frame (2) is provided with a first slot (26) and a second slot (27). The fixed shaft (11) engages with the first slot (26) and the second slot (27).

8. The methane visualization imaging device with a portable laser-coupled camera according to claim 1, characterized in that: A fixed plate (21) is fixedly connected to the lifting frame (2), and a locking plate (22) is slidably connected to the lifting frame (2) adjacent to the fixed plate (21). A limit rod (221) is fixedly connected to one side of the locking plate (22), and the limit rod (221) passes through the fixed plate (21). A first spring (23) is sleeved on the limit rod (221), and the two ends of the first spring (23) abut against the fixed plate (21) and the locking plate (22). The bottom of the locking block is provided with an inclined surface. When the fixed shaft (11) rotates to the first slot (26), the fixed shaft (11) presses the inclined surface at the bottom of the locking block, causing the locking block to move upward and then reset based on the first spring (23).

9. The methane visualization imaging device with a portable laser-coupled camera according to claim 1, characterized in that: A fixing frame (12) is fixed inside the first cover (1), and the servo motor (3) is placed on the fixing frame (12). A clamp (13) is fixed on the fixing frame (12) by screws. The servo motor (3) is fixed inside the first cover (1) through the fixing frame (12) and the clamp (13).

10. The methane visualization imaging device with a portable laser-coupled camera according to claim 8, characterized in that: A sliding rod (24) is fixed to the side wall of the lifting frame (2), and an oblong groove is provided on the side wall of the locking plate (22). The locking plate (22) is slidably connected to the lifting frame (2) via the sliding rod (24), and the sliding rod (24) passes through the oblong groove.

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