Goaf gas measuring device and method

Abstract

The invention discloses a goaf gas measuring device and method, and belongs to the technical field of goaf gas monitoring. Comprising a special pipeline, a movable gas chamber and a gas detection and analysis device, the special pipeline is arranged on the side, close to a goaf, of an air inlet crossheading and an air return crossheading of a coal face, and the special pipeline is gradually buried into the goaf along with coal mining; the movable air chamber collects goaf gas through the holes; the laser is sent into the detection gas chamber through the optical fiber and interacts with the detected gas, and the absorption information of the gas to the light with the specific wavelength is recorded by the photoelectric detector. And the gas analysis module calculates the concentration and components of the gas through an advanced data processing algorithm. According to the device, gas does not need to be pumped out of a goaf for detection, disturbance to the gas in the goaf is avoided, in-situ real-time detection of the gas at any point of the goaf is achieved, meanwhile, laser does not generate electric sparks, the explosion-proof intrinsic safety of the movable gas chamber is guaranteed, and the device is suitable for the fields of coal mine underground safety detection and the like.

Description

Technical Field

[0001] The invention relates to a goaf gas measuring device and method, belonging to the technical field of goaf gas monitoring. Background Art

[0002] Coal mine fire is one of the six major coal mine disasters, posing a serious threat to coal mine production and worker safety. The occurrence of fire may cause poisoning of underground workers, mine shutdown and other hazards, directly affecting the normal production of the mine. In addition, fire may cause gas and coal dust explosions, causing equipment damage, waste of coal resources, consumption of a large amount of manpower and material resources, and causing huge losses to the economy.

[0003] In order to prevent and deal with coal mine fires, goaf gas composition analysis is an important means. The goaf gas composition is an important reference indicator for predicting the degree of spontaneous combustion of coal in the goaf. At the same time, the goaf gas composition is also an important basis for the division of the "three zones" of spontaneous combustion of coal in the goaf. This division provides knowledge for technical measures such as nitrogen injection in the goaf, plugging air leakage, and determining the recovery speed. In order to sample and analyze the gas in the goaf of the fully-mechanized working face, a gas sampling device is required.

[0004] At present, the existing gas sampling devices are mainly used for gas extraction from pre-buried bundle pipes in the inlet and return air lanes of the fully-mechanized mining working face. The position of the pre-buried bundle pipe is gradually buried in the goaf as the working face is mined. After the bundle pipe is buried, it cannot be moved. It is necessary to extract the gas in the bundle pipe in real time as the working face is mined, so as to obtain gas samples at different positions in the goaf. Since the distance between the three zones in the goaf is long, the required bundle pipe distance is also long, and the total volume is large. In order to obtain the gas sample of the measuring point, a large amount of gas in the goaf needs to be extracted, which will cause great disturbance to the gas in the goaf and interfere with the normal air leakage state of the goaf. In addition, since the distance between the three zones in the goaf is long and the mining of the working face is slow, this method has a long measurement cycle for the three zones in the goaf and occupies a lot of manpower and material resources.

[0005] Therefore, a more convenient and freely movable goaf gas detection device is needed nowadays to solve the problems of inconvenience and long time in measuring goaf gas. Summary of the invention

[0006] In view of the shortcomings of the prior art, a goaf gas measurement device and method are provided, which have a simple structure, are easy to use, and can accurately control and collect gas information at different locations in the goaf of a coal mine.

[0007] To achieve the above technical objectives, the present invention adopts the following technical solutions: a gas measuring device for goaf area, comprising a gas analysis device provided with a spiral transmission rod, a special pipe is sleeved on the spiral transmission rod, a special pipe cover is provided at the end of the special pipe for sealing, a bearing cover is provided at the tail of the special pipe for sealing, a movable air chamber driven by the spiral transmission rod is provided on the spiral transmission rod located in the special pipe; a spiral transmission rod outer protruding thread is provided on the outer side of the spiral transmission rod; a bearing a is provided between the bearing cover sealing and the special pipe cover and the end of the spiral transmission rod;

[0008] The special pipeline is a stainless steel pipeline structure, and a plurality of cavities are evenly distributed on the upper semicircular surface of the stainless steel pipeline structure. A slot serving as a track is axially opened in the inner diameter of the stainless steel pipeline structure. The special pipeline is installed on the side of the air inlet chute and the return air chute of the coal mining face close to the goaf. As the coal mine is mined, the special pipeline is gradually buried in the goaf, and the specific burial depth is estimated according to the distribution of the three zones of the goaf.

[0009] The movable air chamber is a closed columnar structure, comprising a columnar inner shell matching the size of the special pipeline, with a left capsule and a right capsule respectively sleeved at both ends of the inner shell, and the movable air chamber is between the left capsule and the right capsule, and an air injection pipeline is also connected in the movable air chamber, and the ends of the air injection pipeline are respectively connected to the left capsule and the right capsule through the inner shell for inflation;

[0010] A semi-cylindrical air chamber is provided in the upper part of the movable air chamber, and a filter for filtering coal dust is provided on the outer shell of the air chamber; a laser collimator is provided at the left end of the air chamber, and a laser coupler and an air extraction pipe are provided at the right end of the air chamber, respectively. The laser collimator is connected to a light-incoming optical fiber, and the laser coupler is connected to a light-returning optical fiber. The laser collimator ensures that the laser is accurately emitted in the direction of emission, and the laser coupler couples the laser after passing through the air chamber into the light-returning optical fiber, ensuring that the laser can be accurately received by the light-returning optical fiber after passing through the air chamber;

[0011] A spiral bayonet pipe is axially arranged in the columnar inner shell, and a thread matching the protruding thread on the outer side of the transmission spiral rod is arranged on the inner wall of the spiral bayonet pipe. The spiral transmission rod passes through the spiral bayonet pipe, and when the spiral transmission rod rotates, the spiral bayonet pipe is driven to move forward and backward along the spiral transmission rod; a plurality of bearings are arranged on the outer side of the movable air chamber, and the bearings match the notches in the special pipe to form a track, and when the movable air chamber moves, it can move on the track in the special pipe;

[0012] The gas analysis device includes a driving device for driving the spiral transmission rod to rotate, a laser emitting device connected to the light-incoming optical fiber, and a gas analysis module connected to the light-returning optical fiber. The laser emitter emits a laser signal to the light-incoming optical fiber, and the feedback laser signal is fed back to the gas detection and analysis device through the light-returning optical fiber to complete the analysis.

[0013] Furthermore, the gas detection and analysis device is a square box structure, and the tail section of the spiral transmission rod is movably connected to the square box structure through a bearing b; the driving device for driving the spiral transmission rod to rotate includes a gear arranged at the tail section of the spiral transmission rod and a hand-cranked gear meshing with the gear, and the gear and the hand-cranked gear are both arranged in the square box structure, and the hand-cranked gear is connected to a rocker arranged on the outside of the square box structure, and a bearing d is provided between the rocker and the square box.

[0014] Furthermore, the laser emitting device includes laser a, laser b and laser c arranged inside the square box structure. Laser a, laser b and laser c are used to emit lasers with a wavelength of 1530-1670nm. The output optical fibers of laser a, laser b and laser c are connected to the input optical fibers through a fiber optic combiner.

[0015] Furthermore, the light-returning optical fiber and the gas analysis module are connected through a matching coupling lens and a photodetector, wherein the tail of the light-returning optical fiber is connected to the coupling lens, and the input end of the gas analysis module is connected to the photodetector through a data line; the gas analysis module is respectively connected to a power button and a laser control button arranged on the outside of the square box structure.

[0016] Furthermore, the length of the transmission screw rod can be spliced ​​and extended as needed, and the transmission screw rod is extended by connecting the head external thread and the tail internal thread end to end; the protruding transmission thread pitch on the outside of the transmission screw rod is 5cm and the outer diameter is 30mm. The transmission screw rod can be spliced ​​as needed, and the two interconnected transmission screw rods are connected by matching external threads and internal threads.

[0017] Furthermore, the special pipe can be extended and spliced ​​by setting flanges at the head and tail as needed.

[0018] Furthermore, the gas analysis device is provided with a power button and a laser control button.

[0019] A detection method for a goaf gas measuring device, the steps of which are as follows:

[0020] Step 1: Determine the laying length of the special pipeline according to the distribution range of the three zones in the goaf and the mining length, and lay the special pipeline directly on the side of the air inlet chute and the return air chute of the coal mining face close to the goaf. The special pipeline is laid and extended as needed, and a special pipeline cover is installed at the end of the special pipeline that penetrates into the goaf to seal it. Bearings are installed in the special pipeline cover, and the bearings are extended along with the special pipeline. During the installation process, the laying of the special pipeline and the installation of the transmission screw rod are carried out simultaneously until the laying length meets the distribution range of the three zones in the goaf of the coal mine. As the production and mining of the coal mine advances, the goaf collapses, and the special pipeline is gradually buried in the goaf;

[0021] When installing the last section of the tail of the transmission screw rod, fit the movable air chamber onto the spiral bayonet pipe transmission screw rod. At the same time, the bearing on the movable air chamber should be stuck in the notch of the special pipe, and a gear is welded at the end of the transmission screw rod for transmission. The special pipe is pre-buried in the air inlet chute and the return air chute of the coal mining face. As the mining progresses, the special pipe is continuously laid, the working face advances forward, and the goaf collapses. Part of the special pipe near the working face will be automatically buried in the goaf. At this time, due to the protection of the special pipe, the collapsed objects will not fall into the special pipe.

[0022] Step 2: Install a tee pipe and a pressure gauge at the tail end of the gas injection pipeline, connect the tee pipe to the coal mine's own compressed air system pipeline, and connect the exhaust pipeline to the mine vacuum pump; connect the optical fiber to the laser emitting device in the gas analysis and detection device;

[0023] Step 3: As the working face advances, the special pipe is gradually buried in the goaf as the goaf collapses. When the end of the special pipe is buried in the suffocation zone of the goaf, measurement begins: Use a hand-cranked transmission screw rod to send the movable air chamber into the collapsed goaf;

[0024] Step 4: When the movable air chamber moves to the designated measuring point, open the three-way valve b of the coal mine compressed air system pipeline, and inject air into the capsules on the left and right sides through the air injection pipeline. The gas first enters the inner shell through the air injection pipeline, and then enters the capsule through the holes on the surface of the inner shell to make the capsule bulge. When the pressure gauge connected to the capsule shows a reading of 0.5 atmospheres, close the three-way valve b to stop the gas supply. After the pressure gauge reading stabilizes, it means that the capsule has good sealing performance. The left and right ends of the special pipeline are closed to form a sealed air chamber between the left and right capsules. Since the goaf has collapsed, the gas on the left and right sides of the measuring point can be prevented from being drawn into the air chamber. Only the goaf gas at the location of the air chamber is collected. Then, the mine intrinsically safe negative pressure gas collector is opened to draw the goaf gas into the air chamber.

[0025] Step 5: Continue to pump gas for the set time, and use a portable gas detector to roughly check the extracted gas. When the portable gas detector displays stable data, it means that the gas composition and concentration in the gas chamber are stable. At this time, turn on the power button on the gas analysis device, and then turn on the laser control button. The wavelengths of laser a, laser b, and laser c cover the absorption peaks of the spontaneous combustion index gases of coal in the goaf: methane, carbon monoxide, and carbon dioxide. The lasers generated by laser a, laser b, and laser c are introduced into the gas chamber through the light-input optical fiber and the laser collimator. After the laser passes through the gas chamber, the laser light intensity changes due to the absorption of methane, carbon monoxide, and carbon dioxide in the sealed gas chamber. The laser light is coupled by the laser coupler and guided back to the return light optical fiber. The return light optical fiber sends the laser back to the photoelectric detector. The gas analysis module calculates the gas concentration in the gas chamber by analyzing the changes in the incident laser light intensity and the output light intensity, and reads the data to detect the concentration of the spontaneous combustion index gas in the goaf.

[0026] Step 6: After the measurement of this measuring point is completed, open the three-way valve a at the gas injection pipeline interface to release the gas in the capsule, so that the left capsule and the right capsule return to their original state, press the gas analysis device power button and laser control button again to turn off the laser, move the gas chamber to the next measuring point for measurement, and repeat steps 4 to 6 until the data collection is completed.

[0027] Furthermore, the mining vacuum pump uses a mining intrinsically safe negative pressure gas collector, model CFB10, with a flow rate of 10L / min and a gas injection pipe diameter of 2cm.

[0028] Furthermore, the moving distance of the movable air chamber is determined by the connected distance tape or the number of turns of the hand-cranked gear. The gear ratio of the hand-cranked gear to the transmission screw rod is 4:1, and the pitch of the external protruding thread of the transmission screw rod is 5 cm. Therefore, the hand-cranked gear rotates 1 turn and the transmission screw rod rotates 4 turns, and the movable air chamber advances forward 0.2 m. The number of turns of the hand-cranked gear is recorded to estimate the travel distance of the movable air chamber and determine the position of the movable air chamber in the goaf.

[0029] Beneficial effects: The present invention lays a special pipeline during the mining process, and the special pipeline is provided with uniform holes to prevent the entry of collapsed objects. Then, a movable air chamber is used to collect gas at a fixed point through the special pipeline with holes. The holes of the special pipeline are evenly distributed above the special pipeline. At the same time, the special pipeline runs through the entire goaf, and can collect gas at any position in the goaf. When the movable air chamber moves to the area to be detected, the inflatable capsules at both ends are inflated to prevent the collected gas from leaking from other positions of the special pipeline when collecting gas, thereby effectively improving the measurement accuracy. The present invention solves the problem that the traditional three-zone gas measurement device in the goaf can only collect gas at fixed points. At the same time, the device does not need to collect gas, and uses laser to perform real-time in-situ detection of the gas in the air chamber, thereby avoiding disturbance of the goaf gas, and the accuracy can also meet the three-zone gas measurement requirements of the goaf, saving a lot of manpower and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the detection of the goaf gas measuring device of the present invention;

[0031] Figure 2 It is a top view schematic diagram of the detection of the goaf gas measuring device of the present invention;

[0032] Figure 3 A schematic diagram of a special pipeline structure for detecting a gas measuring device for a goaf area according to the present invention;

[0033] Figure 4 A right view of the end of the goaf for burying the special pipeline of the goaf gas measuring device of the present invention into the goaf;

[0034] Figure 5 It is a cross-sectional view of the movable gas chamber structure of the goaf gas measuring device of the present invention;

[0035] Figure 6 It is an overall schematic diagram of the spiral transmission rod in the goaf gas measuring device of the present invention;

[0036] Figure 7 A schematic diagram of a section of a spiral transmission rod in a goaf gas measuring device of the present invention;

[0037] Figure 8 The figure is a schematic diagram of the arrangement of an embodiment of the present invention in a coal mine working face.

[0038] In the figure, 1. Special pipeline; 2. Left capsule; 3. Laser collimator; 4. Filter; 5. Laser coupler; 6. Return light optical fiber; 7. Light-incoming optical fiber; 8. Air extraction pipe; 9. Gear; 10. Bearing c; 11. Right capsule; 12. Air injection pipe; 13. Screw transmission rod; 14. Special pipeline cover; 15. Notch in pipeline; 16. Bearing a; 17. External thread of transmission screw rod head; 18. Internal thread of transmission screw rod tail; 19. Movable air chamber; 20. Air chamber; 21. Screw bayonet pipeline; 22. Transmission The outer protruding thread of the spiral rod; 23, the inner shell; 24, the optical fiber combiner; 25, the rocker; 26, the bearing d; 27, the power button; 28, the laser control button; 29, the laser a; 30, the laser b; 31, the coupling lens; 32, the photodetector; 33, the data line; 34, the gas analysis module; 35, the hand crank gear; 36, the laser c; 37, the bearing b; 38, the inner shell hole; 39, the three-way pipe; 40, the three-way pipe valve a; 41, the three-way pipe valve b; 42, the pressure gauge Specific implementation plan

[0039] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0040] like Figure 1 and Figure 2 As shown, the present invention discloses a goaf gas measuring device, including a gas analysis device provided with a spiral transmission rod 13, a special pipe 1 is sleeved on the spiral transmission rod 13, a special pipe cover 14 is provided at the end of the special pipe 1 for sealing, a bearing cover is provided at the tail of the special pipe 1 for sealing, and the special pipe 1 can be extended and spliced ​​by setting flanges at the head and tail as needed. A movable air chamber driven by the spiral transmission rod 13 is provided on the spiral transmission rod 13 located in the special pipe 1; wherein the outer side of the spiral transmission rod 13 is provided with a transmission spiral rod external protruding thread 22; a bearing a16 is provided between the bearing cover plugging and the end of the special pipe cover 14 and the spiral transmission rod 13; the length of the transmission spiral rod 13 can be spliced ​​and extended as needed, and the transmission spiral rod 13 is extended by connecting the head external thread 17 and the tail internal thread 18 end to end; the protruding transmission thread 22 on the outside of the transmission spiral rod 13 has a pitch of 5 cm and an outer diameter of 30 mm. The transmission spiral rod 13 can be spliced ​​as needed, and the two interconnected transmission spiral rods 13 are connected by matching external threads 17 and internal threads 18, such as Figure 6 and Figure 7 shown.

[0041] like Figure 3 and Figure 4As shown, the special pipeline 1 is a stainless steel pipeline structure, and a plurality of cavities are evenly distributed on the upper semicircular surface of the stainless steel pipeline structure. An inner pipeline slot 15 serving as a track is axially opened in the inner diameter of the stainless steel pipeline structure. The special pipeline 1 is installed on the side of the air inlet chute and the return air chute of the coal mining face close to the goaf. With the mining of the coal mine, the special pipeline 1 is gradually buried in the goaf, and the specific buried depth is estimated according to the distribution of the three zones of the goaf.

[0042] The movable air chamber is a closed columnar structure, and includes a columnar inner shell 23 whose size matches that of the special pipe 1. The left capsule 2 and the right capsule 11 are respectively sleeved at both ends of the inner shell 23. The movable air chamber 19 is between the left capsule 2 and the right capsule 11. The movable air chamber 19 is also connected to an air injection pipe 12. The ends of the air injection pipe 12 are respectively connected to the left capsule 2 and the right capsule 11 through the inner shell 23 for inflation.

[0043] like Figure 5 As shown, a semi-cylindrical air chamber 20 is provided in the upper part of the movable air chamber 19, and a filter 4 for filtering coal dust is provided on the outer shell of the air chamber 20; a laser collimator 3 is provided at the left end of the air chamber 20, and a laser coupler 5 and an exhaust pipe 8 are provided at the right end of the air chamber 20, respectively. The laser collimator 3 is connected to a light-incoming optical fiber 7, and the laser coupler 5 is connected to a light-returning optical fiber 6. The laser collimator 3 ensures that the laser emission direction is accurate, and the laser coupler 5 couples the laser after passing through the air chamber into the light-returning optical fiber 6 to ensure that the laser can be accurately received by the light-returning optical fiber 6 after passing through the air chamber; the laser emitting device includes a laser a29, a laser b30 and a laser c36 arranged on the inner side of the square box structure, and the laser a29, the laser b30 and the laser c36 use butterfly package lasers of Thorlabs of the United States, and their models are NLK1C5EAAA, NLK1L5EAAA, ... 1U5EAAA, can emit lasers with wavelengths of 1530-1565nm, 1565-1625nm, 1625-1670nm respectively, and the wavelength bands cover the absorption peaks of 1550nm, 1570nm and 1650nm of carbon monoxide, carbon dioxide and methane respectively. The output optical fibers of laser a29, laser b30 and laser c36 are connected to the light input optical fiber 7 through the optical fiber combiner 24; the return optical fiber 6 and the gas analysis module 34 are connected through a matching coupling lens 31 and a photodetector 32, wherein the tail of the return optical fiber 6 is connected to the coupling lens 31, and the input end of the gas analysis module 34 is connected to the photodetector 32 through a data line 33; the gas analysis module 34 is respectively connected to a power button 27 and a laser control button 28 arranged on the outside of the square box structure; the gas analysis device is provided with a power button 27 and a laser control button 28.

[0044] A spiral bayonet pipe 21 is axially arranged in the columnar inner shell 23, and a thread matching the protruding thread 22 on the outer side of the transmission screw rod is arranged on the inner wall of the spiral bayonet pipe 21, and the spiral transmission rod 13 passes through the spiral bayonet pipe 21. When the spiral transmission rod 13 rotates, the spiral bayonet pipe 21 is driven to move forward and backward along the spiral transmission rod 13; a plurality of bearings 10 are arranged on the outer side of the movable air chamber 19, and the bearings 10 match the inner notches 15 in the special pipe 1 to form a track, and when the movable air chamber moves, it can move on the track in the special pipe 1;

[0045] The gas analysis device includes a driving device for driving the spiral transmission rod 13 to rotate, a laser emitting device connected to the light-incoming optical fiber 7, and a gas analysis module 38 connected to the light-returning optical fiber 6. The laser emitter emits a laser signal to the light-incoming optical fiber 7, and the feedback laser signal is fed back to the gas detection and analysis device through the light-returning optical fiber 6 to complete the analysis; the gas detection and analysis device is a square box structure, and the tail section of the spiral transmission rod 13 is movably connected to the square box structure through a bearing b37; the driving device for driving the spiral transmission rod 13 to rotate includes a gear 9 arranged at the tail section of the spiral transmission rod 13 and a hand-cranked gear 35 meshing with the gear 9, and the gear 9 and the hand-cranked gear 35 are both arranged in the square box structure, and the hand-cranked gear 35 is connected to a rocker 25 arranged on the outside of the square box structure, and a bearing d26 is provided between the rocker 25 and the square box.

[0046] like Figure 8 As shown, a detection method of a goaf gas measuring device,

[0047] Step 1: Determine the laying length of the special pipeline 1 according to the distribution range of the three zones in the goaf, such as Figure 8 As shown, the special pipe is laid on the side of the air inlet chute and the return air chute of the coal mining face close to the goaf, and the special pipes are connected by flanges. A special pipe cover 14 is installed at one end of the special pipe 1 that penetrates into the goaf, and a bearing 16 is installed in the special pipe cover 14. The bearing 16 is fitted on the protruding external thread 17 of the head of the transmission screw rod 13. The transmission screw rod 13 is connected end to end through the head external thread 17 and the tail internal thread 18 to extend its length. During the installation process, the laying of the special pipe 1 and the installation of the transmission screw rod 13 are carried out simultaneously until the laying length meets the three-zone distribution range of the goaf in the coal mine.

[0048] When installing the last section of the transmission screw rod 13, the movable air chamber is fitted on the transmission screw rod 13 of the spiral bayonet pipe 21, and the bearing 10 on the movable air chamber should be just stuck in the groove 15 in the special pipe. The pipe groove 15 serves as the groove in the track pipe for the bearing 10 to move. At the same time, the gear 9 is welded at the end of the transmission screw rod 13 for transmission;

[0049] Step 2: After the movable air chamber is installed, the right interface of the movable air chamber is connected to the corresponding device in turn, wherein the gas injection pipeline 12 is connected to the tee pipe 39 and the pressure gauge 42, the tee pipe 39 is connected to the coal mine's own compressed air system pipeline, the light-incoming optical fiber 7 and the return optical fiber 6 are respectively connected to the laser 29, 30, 36, and the photoelectric detector 32, and the exhaust pipeline 8 is connected to the mine vacuum pump. The mine vacuum pump uses a mine intrinsically safe negative pressure gas collector, model CFB10, flow rate 10L / min, the gas injection pipeline 12 has a diameter of 2cm, and the gas injection pipeline 12 and the compressed air system pipeline are connected with a tee pipe 39 and a pressure gauge 42.

[0050] Step 3: After the special pipe and the movable air chamber are fully installed, as the working face moves forward, the special pipe gradually penetrates into the goaf, and the measurement starts when the end of the pipe is estimated to be buried in the suffocation zone of the goaf. During the measurement, the movable air chamber is sent into the goaf by means of the manual transmission screw 13, wherein the gear ratio of the manual gear and the transmission screw gear 9 is 4:1, and the pitch of the external protruding thread 22 of the transmission screw is 5cm, so the manual gear rotates 1 circle, the transmission screw rotates 4 circles, and the movable air chamber is advanced 0.2m. The number of circles of the manual gear is recorded to estimate the travel distance of the movable air chamber and determine its position in the goaf.

[0051] Step 4: When the movable air chamber is moved to the designated measuring point by hand cranking, open the three-way pipe valve b41 of the coal mine compressed air system pipeline, and inject air into the capsules on the left and right sides through the air injection pipe 12. The gas first enters the inner shell 23 through the air injection pipe 12, and then enters the capsule through the hole 38 on the surface of the inner shell 23 to make the capsule bulge. When the pressure gauge 42 connected to the capsule shows a reading of 0.5 atmospheres, close the three-way pipe valve b41 to stop the gas supply. After the reading of the pressure gauge 42 stabilizes, it means that the capsule has good sealing performance. Close the special pipes 1 on both sides of the capsule to form a sealed air chamber between the capsules 2 and 11 on the left and right sides, where the volume of the movable air chamber is about 3.7L. Then open the mine intrinsically safe negative pressure gas collector to draw the gas from the goaf into the air chamber.

[0052] Step 5: After pumping gas for a while, use a portable gas detector to roughly check the extracted gas. When the portable gas detector displays stable data, it means that the gas composition and concentration in the gas chamber are stable. At this time, turn on the gas analysis device power button 31, and then turn on the laser control button 28. The lasers generated by lasers 29, 30, and 36 are introduced into the gas chamber through the light-input optical fiber 7 and the laser collimator 3. After the laser passes through the gas chamber, its light intensity changes due to the absorption of the gas in the sealed gas chamber. After being coupled by the laser coupler 5, it is guided back to the return light optical fiber 6. The return light optical fiber 6 sends the laser back to the photoelectric detector 32. The gas analysis module 34 calculates the gas concentration in the gas chamber by analyzing the changes in the incident laser light intensity and the outgoing light intensity, and reads the data.

[0053] Step 6: After the measurement of the measuring point is completed, open the three-way valve a 40 at the interface of the gas injection pipeline 12 to release the gas in the capsule and restore the capsule to its original state. Press the gas analysis device power button 27 and the laser control button 28 again to turn off the laser, shake the gear 35 to move the movable gas chamber to the next measuring point for measurement, and repeat steps 4 to 6 until the data collection is completed.

[0054] Measuring principle: Direct absorption spectroscopy

[0055] According to the theory of molecular spectroscopy, polyatomic asymmetric molecular gases can absorb infrared light. That is, when infrared light passes through the gas molecules to be tested, if the spectrum of the incident infrared light coincides with the absorption spectrum of the gas molecules, the molecules can absorb the energy of the infrared radiation, and the light intensity at the corresponding spectrum will be weakened. The gas molecules show absorption of infrared radiation. The above phenomenon conforms to the Lambert-Beer law, as shown in formula 1.1. The concentration of the gas can be detected using direct absorption spectroscopy technology.

[0056] I(λ)=I0(λ)e -k(λ)cl Formula 1-1

[0057] In the formula, the initial intensity of the light source is I0(λ), the light intensity after being absorbed by the gas to be measured is I(λ), the concentration of the gas to be measured is C, the absorption coefficient is k(λ), and the length of light passing through the gas is l.

Claims

1. A gas measuring device for goaf, characterized in that; The invention comprises a gas analysis device provided with a spiral transmission rod (13), wherein a special pipe (1) is sleeved on the spiral transmission rod (13), a special pipe cover (14) is provided at the end of the special pipe (1) for sealing, a bearing cover is provided at the tail of the special pipe (1), and a movable air chamber driven by the spiral transmission rod (13) is provided on the spiral transmission rod (13) located in the special pipe (1); wherein an outer protruding thread (22) of the transmission spiral rod is provided on the outer side of the spiral transmission rod (13); and a bearing a (16) is provided between the bearing cover sealing and the special pipe cover (14) and the end of the spiral transmission rod (13); The special pipeline (1) is a stainless steel pipeline structure, and a plurality of cavities are evenly distributed on the upper semicircular surface of the stainless steel pipeline structure. An inner pipeline slot (15) serving as a track is axially opened in the inner diameter of the stainless steel pipeline structure. The special pipeline (1) is installed on the side of the air inlet chute and the return air chute of the coal mining face close to the goaf. As the coal mine is mined, the special pipeline (1) is gradually buried in the goaf, and the specific burial depth is estimated according to the distribution of the three zones in the goaf. The movable air chamber is a closed columnar structure, comprising a columnar inner shell (23) whose size matches that of the special pipe (1), a left capsule (2) and a right capsule (11) being respectively sleeved at both ends of the inner shell (23), a movable air chamber (19) being located between the left capsule (2) and the right capsule (11), an air injection pipe (12) being connected to the movable air chamber (19), and ends of the air injection pipe (12) being respectively connected to the left capsule (2) and the right capsule (11) through the inner shell (23) for inflation; A semi-cylindrical air chamber (20) is provided in the upper part of the movable air chamber (19), and a filter (4) for filtering coal dust is provided on the outer shell of the air chamber (20); a laser collimator (3) is provided at the left end of the air chamber (20), and a laser coupler (5) and an air extraction pipe (8) are provided at the right end of the air chamber (20); the laser collimator (3) is connected to a light-incoming optical fiber (7), and the laser coupler (5) is connected to a light-returning optical fiber (6); the laser collimator (3) ensures that the laser is accurately emitted in the direction of emission, and the laser coupler (5) couples the laser light after passing through the air chamber into the light-returning optical fiber (6), so as to ensure that the laser light can be accurately received by the light-returning optical fiber (6) after passing through the air chamber; A spiral bayonet pipe (21) is axially arranged inside the columnar inner shell (23), and a thread matching the protruding thread (22) on the outer side of the transmission spiral rod is arranged on the inner wall of the spiral bayonet pipe (21), and the spiral transmission rod (13) passes through the spiral bayonet pipe (21), and when the spiral transmission rod (13) rotates, the spiral bayonet pipe (21) is driven to move forward and backward along the spiral transmission rod (13); a plurality of bearings (10) are arranged outside the movable air chamber (19), and the bearings (10) match the inner notches (15) of the special pipe (1) to form a track, and when the movable air chamber moves, it can move on the track inside the special pipe (1); The gas analysis device comprises a driving device for driving the spiral transmission rod (13) to rotate, a laser emitting device connected to the light-incoming optical fiber (7), and a gas analysis module (38) connected to the light-returning optical fiber (6); the laser emitter emits a laser signal to the light-incoming optical fiber (7), and the feedback laser signal is fed back to the gas detection and analysis device through the light-returning optical fiber (6) to complete the analysis.

2. A goaf gas measuring device according to claim 1, characterized in that; The gas detection and analysis device is a square box structure. The tail section of a spiral transmission rod (13) is movably connected to the square box structure through a bearing b (37). A driving device for driving the spiral transmission rod (13) to rotate comprises a gear (9) arranged at the tail section of the spiral transmission rod (13) and a hand-cranked gear (35) meshing with the gear (9). The gear (9) and the hand-cranked gear (35) are both arranged in the square box structure. The hand-cranked gear (35) is connected to a rocker (25) arranged outside the square box structure. A bearing d (26) is arranged between the rocker (25) and the square box.

3. A goaf gas measuring device according to claim 2, characterized in that; The laser emitting device comprises a laser a (29), a laser b (30) and a laser c (36) arranged inside a square box structure. The laser a (29), the laser b (30) and the laser c (36) are used to emit laser light with a wavelength of 1530-1670 nm. The laser light in this wavelength band can cover the absorption peak of the gas to be measured. The output optical fibers of the laser a (29), the laser b (30) and the laser c (36) are connected to the light input optical fiber (7) through an optical fiber combiner (24).

4. A goaf gas measuring device according to claim 2, characterized in that; The light-returning optical fiber (6) and the gas analysis module (34) are connected via a matching coupling lens (31) and a photoelectric detector (32), wherein the tail of the light-returning optical fiber (6) is connected to the coupling lens (31), and the input end of the gas analysis module (34) is connected to the photoelectric detector (32) via a data line (33); the gas analysis module (34) is respectively connected to a power button (27) and a laser control button (28) arranged on the outside of the square box structure.

5. A goaf gas measuring device according to claim 1, characterized in that; The length of the transmission screw rod (13) can be spliced ​​and extended as required, and the transmission screw rod (13) is extended by connecting the head external thread (17) and the tail internal thread (18) end to end; the protruding transmission thread (22) outside the transmission screw rod (13) has a pitch of 5 cm and an outer diameter of 30 mm. The transmission screw rod (13) can be spliced ​​as required, and the two interconnected transmission screw rods (13) are connected by matching external threads (17) and internal threads (18).

6. A goaf gas measuring device according to claim 1, characterized in that; The special pipe (1) can be extended and spliced ​​by arranging flanges at the head and tail as required.

7. A goaf gas measuring device according to claim 1, characterized in that; The gas analysis device is provided with a power button (27) and a laser control button (28).

8. A detection method using the goaf gas measuring device according to any one of claims 1 to 7, characterized in that: Here are the steps: Step 1: Determine the laying length of the special pipeline (1) according to the distribution range of the three zones of the goaf and the mining length, and lay the special pipeline (1) directly on the side of the air inlet chute and the return air chute of the coal mining face close to the goaf. The special pipeline (1) is laid and extended as needed, and a special pipeline cover (14) is installed at the end of the special pipeline (1) that penetrates into the goaf for sealing. A bearing (16) is installed in the special pipeline cover (14), and the bearing (16) is extended along with the special pipeline (1). During the installation process, the laying of the special pipeline (1) and the installation of the transmission screw rod (13) are carried out simultaneously until the laying length meets the distribution range of the three zones of the goaf in the coal mine. As the production and mining of the coal mine advances, the goaf collapses, and the special pipeline (1) is gradually buried in the goaf; When installing the last section of the tail of the transmission screw rod (13), the movable air chamber is fitted on the transmission screw rod (13) of the spiral bayonet pipe (21), and the bearing (10) on the movable air chamber should be exactly stuck in the notch (15) in the special pipe, and a gear (9) is welded at the end of the transmission screw rod (13) for transmission; the special pipe (1) is pre-buried in the air inlet chute and the return air chute of the coal mining working face. As the mining progresses, the special pipe (1) is continuously laid, the working face advances forward, and the goaf collapses. Part of the special pipe (1) adjacent to the working face will automatically be buried in the goaf. At this time, due to the protection of the special pipe (1), the collapsed objects will not fall into the special pipe (1); Step 2: Connect the tail end of the gas injection pipeline (12) to the compressed air system pipeline of the coal mine itself, and set a pressure gauge (42) on the gas injection pipeline (12) through a three-way pipe (39), and connect the gas extraction pipeline (8) to a mining vacuum pump; connect the light-incoming optical fiber (7) to the laser emitting device in the gas analysis and detection device; Step 3: As the working face advances forward, the special pipe (1) is gradually buried in the goaf as the goaf collapses. When the end of the special pipe (1) is buried in the suffocation zone of the goaf, measurement begins: use a hand-cranked transmission screw rod (13) to send the movable air chamber into the collapsed goaf; Step 4: When the movable air chamber moves to the designated measuring point, open the three-way pipe valve b (41) of the coal mine compressed air system pipeline, and inject gas into the left capsule (2) and the right capsule (11) through the gas injection pipeline (12). The gas first enters the inner shell (23) through the gas injection pipeline (12), and then enters the capsule through the hole (38) on the surface of the inner shell (23) to make the capsule bulge. When the pressure gauge (42) connected to the capsule shows a reading of 0.5 atmospheres, close the three-way pipe valve b ( 41) Stop the gas supply. When the pressure gauge (42) reading is stable, it means that the capsule is well sealed. The left and right ends of the special pipeline (1) are sealed to form a sealed air chamber (20) between the left and right capsules. Since the goaf has collapsed, the gas on the left and right sides of the measuring point can be prevented from being drawn into the air chamber (20). Only the goaf gas at the location of the air chamber (20) is collected. Then, the intrinsically safe negative pressure gas collector for mining is turned on to draw the goaf gas into the air chamber using negative pressure. Step 5: After the continuous gas extraction reaches the set time, turn on the power button (27) on the gas analysis device, and then turn on the laser control button (28). The wavelengths of laser a (29), laser b (30), and laser c (36) cover the absorption peaks of the spontaneous combustion index gases of coal in the goaf: methane, carbon monoxide, and carbon dioxide. The lasers generated by laser a (29), laser b (30), and laser c (36) are introduced into the gas chamber (20) through the light input optical fiber (7) and the laser collimator (3). After the laser passes through the gas chamber (20), the laser light intensity changes due to the absorption of methane, carbon monoxide, and carbon dioxide in the sealed gas chamber. The laser light is coupled by the laser coupler (5) and then guided back to the return optical fiber (6). The return optical fiber (6) sends the laser light back to the photoelectric detector (32). The gas analysis module (34) calculates the gas concentration in the gas chamber by analyzing the changes in the incident laser light intensity and the output laser light intensity, and reads the data to detect the concentration of the spontaneous combustion index gas in the goaf. Step 6: After the measurement of the measuring point is completed, open the three-way valve a (40) at the interface of the gas injection pipeline (12) to release the gas in the capsule, so that the left capsule (2) and the right capsule (11) return to their original state, press the gas analysis device power button (27) and the laser control button (28) again to turn off the laser, move the gas chamber to the next measuring point for measurement, and repeat steps 4 to 6 until the data collection is completed.

9. The detection method according to claim 8, characterized in that: The mining vacuum pump uses a mining intrinsically safe negative pressure gas collector, model CFB10, with a flow rate of 10L / min and a gas injection pipeline (12) with a diameter of 2cm.

10. The detection method according to claim 8, characterized in that; The moving distance of the movable air chamber is determined by a connected distance tape or according to the number of turns of the hand-cranked gear (35). The gear ratio of the hand-cranked gear (35) to the transmission screw gear (9) is 4:1, and the pitch of the external protruding thread (22) of the transmission screw is 5 cm. Therefore, when the hand-cranked gear rotates 1 turn, the transmission screw rotates 4 turns, and the movable air chamber moves forward 0.2 m. The number of turns of the hand-cranked gear (35) is recorded to estimate the travel distance of the movable air chamber and determine the position of the movable air chamber in the goaf.

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