Experimental device for simulating the influence of downhole environment on the near-infrared spectrum of coal and rock

Abstract

The invention discloses an experimental device for simulating the influence of underground environment on the near-infrared spectrum of coal and rock, belonging to the technical field of underground environment simulation experiments. The invention comprises a simulation box, a stage, a near-infrared spectrometer, an optical fiber probe, a linear moving mechanism, a stepless speed regulation air pump and a temperature control mechanism. Among them, the stage is located inside the simulation box. One end of the optical fiber probe is connected to the near-infrared spectrometer, and the other end is inserted into the simulation box from the top of the simulation box and is hermetically connected to the wall surface of the simulation box. The linear moving mechanism is used to push the stage to move linearly along the horizontal plane. The stepless speed regulation air pump is used to drive the gas in the simulation box to circulate. The temperature control mechanism is used to control the temperature inside the simulation box. The invention can simulate various underground environmental factors and can be used to analyze the influence of the underground environment on the near-infrared spectrum data of coal and rock samples, so as to correct the near-infrared spectrum data of coal and rock samples, which is conducive to more accurately identifying the coal and rock interface.

Description

Technical Field

[0001] The present invention relates to the technical field of underground environment simulation experiments, especially for simulating the drilling environment, and specifically provides an experimental device for simulating the influence of the underground environment on the near-infrared spectrum of coal and rock. Background Technique

[0002] Drilling technology is an effective technical means for the efficient treatment of gas in current underground coal mines, advanced drainage of roof water, and grouting reinforcement of floor water isolation layers. It plays an irreplaceable role in fields such as coal mine gas extraction, water disaster prevention, and detection of concealed disaster-causing geological factors, and is of extremely important significance for ensuring coal mine safety production, increasing clean energy supply, and reducing greenhouse gas emissions.

[0003] To ensure the gas extraction effect, reduce extraction blind spots, and clarify the mining range, real-time detection and in-situ identification of the lithological data of coal seams and roof and floor rock strata are important tasks during the drilling process. The identification results of the coal seam and rock stratum interface are the direct evaluation indicators for the acceptance of drilling engineering quality (《Coal Geological Drilling Regulations》(MT / T 1076 - 2008)). In addition, the spatial distribution data of coal seams and rock strata based on drilling identification are the basic key data for the geological guarantee system of transparent working faces in underground coal mines. Efficient and accurate detection of the lithology and interface of coal-rock strata during the drilling process can strongly support the three-dimensional refined geological modeling work that integrates geological, seismic, and mining data. Therefore, the real-time identification of the coal-rock interface during drilling is one of the key technologies for constructing a high-precision geological model and an important research direction for the future of less manned and intelligent coal mining.

[0004] Chinese Patent with publication number CN118585810A discloses a real-time online precise identification method for coal and rock based on spectral technology. It uses the near-infrared spectral data of coal and rock samples under the illumination of a light source to train an identification model, and then obtains the near-infrared spectral data of the coal and rock to be identified and uses this identification model to identify the coal-rock interface in real time. However, the underground environment is complex, and many factors in the drilling hole will affect the infrared spectrum. For example, the temperature, dust concentration, etc. in the drilling hole. Therefore, it is necessary to determine the influence of each factor on the near-infrared spectrum in order to correct the spectral data. Summary of the Invention

[0005] In order to solve at least one of the above problems, the purpose of the present invention is to provide an experimental device for simulating the influence of the underground environment on the near-infrared spectrum of coal and rock, which is used to analyze the influence of the drilling environment on the near-infrared spectral data of coal and rock samples.

[0006] In order to achieve the above purpose, the technical solution provided by the present invention is as follows:

[0007] An experimental device for simulating the influence of the underground environment on the near-infrared spectrum of coal and rock, comprising:

[0008] A simulation box with a closed structure;

[0009] A stage located inside the simulation chamber for carrying coal and rock samples;

[0010] Near-infrared spectrometer;

[0011] An optical fiber probe with one end connected to the near-infrared spectrometer and the other end inserted into the simulation chamber from the top of the simulation chamber and hermetically connected to the wall of the simulation chamber. The optical fiber probe includes an incident optical fiber and an outgoing optical fiber, and is used to obtain near-infrared spectral data of coal and rock samples. The optical fiber probe can move along its axis;

[0012] A rangefinder fixed to one end of the optical fiber probe facing the coal and rock samples and facing the top surface of the coal and rock samples;

[0013] A linear moving mechanism for pushing the stage to move linearly along the horizontal plane;

[0014] A stepless speed regulation air pump for driving the gas in the simulation chamber to circulate;

[0015] A dust collector for removing dust from the circulating gas leaving the simulation chamber;

[0016] A dust feeding mechanism for adding dust to the circulating gas entering the simulation chamber;

[0017] A temperature control mechanism for controlling the temperature inside the simulation chamber.

[0018] As a specific embodiment of the present invention, the temperature control mechanism includes an oil bath and a heater. Among them, heat-conducting oil is stored in the oil bath, and the heater adopts closed-loop control to stably control the temperature of the heat-conducting oil. The simulation chamber is immersed in the oil bath.

[0019] As a specific embodiment of the present invention, the stage is suspended inside the simulation chamber, and the linear moving mechanism includes:

[0020] A screw rod fixed in the simulation chamber in a rotatable manner. The middle part of the screw rod is threadedly connected to the stage;

[0021] A guide rod fixed inside the simulation chamber and parallel to the screw rod. The guide rod passes through the stage and has a clearance fit with it;

[0022] A high-temperature resistant motor with an output shaft coaxially connected to the screw rod.

[0023] As a specific embodiment of the present invention, a air distribution plate is arranged at the gas inlet end of the simulation chamber. The air distribution plate is arranged vertically and separated from the gas inlet of the simulation chamber, so as to form a gas distribution cavity between the inner wall of the simulation chamber and the air distribution plate. A plurality of Z-shaped flow channels are arranged in an array on the air distribution plate; the gas inlet of the gas distribution cavity is located at the bottom of the gas distribution cavity.

[0024] Furthermore, a dust collection chamber is arranged at the bottom of the simulation chamber. Dust through-holes are arranged in an array at the part of the bottom plate of the simulation chamber outside the gas distribution chamber, and the simulation chamber is communicated with the dust collection chamber through the dust through-holes.

[0025] Furthermore, the dust through-hole is an inverted conical hole.

[0026] As a specific embodiment of the present invention, the stage includes a base plate, a stage plate and a rotating shaft. The base plate is connected to the linear moving mechanism. Wherein, the base plate is provided with an ear extending in the normal direction, the rotating shaft is fixedly connected to the stage plate and rotatably connected to the ear;

[0027] This experimental device further includes an angle adjustment mechanism, and the angle adjustment mechanism includes:

[0028] A ratchet wheel fixedly connected to the rotating shaft, which is a disc structure with a one-way tooth groove on the outer edge;

[0029] A first pawl with one end rotatably connected to the ear and the other end abuting against the outer edge tooth groove of the ratchet wheel;

[0030] A first swing rod with one end rotatably connected to the rotating shaft;

[0031] A second pawl with one end rotatably connected to the first swing rod and the other end abuting against the outer edge tooth groove of the ratchet wheel;

[0032] A second swing rod with one end rotatably connected to the base plate. The free ends of the second swing rod and the first swing rod are respectively fixed at both ends of a rope, and the rotation planes of the second swing rod and the first swing rod are perpendicular to each other;

[0033] A blocking rod horizontally fixed in the simulation chamber, the blocking rod extends along the direction of the horizontal movement of the stage, and the center line of the blocking rod is located on the rotation plane of the second swing rod;

[0034] Wherein, the first pawl and the second pawl prevent the ratchet wheel from rotating in the reverse direction. When the second swing rod is separated from the blocking rod, the first swing rod rotates in the reverse direction to the limit position under the action of the return spring and drives the free end of the second swing rod to rotate in the reverse direction to a position higher than the blocking rod; when the stage moves towards the blocking rod until the side wall of the second swing rod abuts against the blocking rod and then continues to move in the same direction, the blocking rod pushes the second swing rod to rotate forward until the free end of the second swing rod abuts against the annular outer wall of the blocking rod.

[0035] The beneficial effects of the present invention are as follows:

[0036] The experimental device for simulating the influence of the underground environment on the near-infrared spectrum of coal and rock can simulate the underground environment and obtain the near-infrared spectrum data of coal and rock samples under this environment, which is used to analyze the influence of the underground environment on the near-infrared spectrum of coal and rock samples, so as to correct the near-infrared spectrum data of coal and rock samples, facilitating more accurate identification of the coal-rock interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0038] Figure 2 is Figure 1 a schematic diagram of the linear moving mechanism in;

[0039] Figure 3 It is a schematic diagram of the overall structure of another embodiment of the present invention.

[0040] Figure 4 is Figure 3 a schematic diagram of the simulation box in;

[0041] Figure 5 is Figure 3 a schematic diagram of the angle adjustment mechanism in;

[0042] Figure 6 is Figure 3 a schematic diagram of the combination structure of the swing rod and the ratchet wheel in;

[0043] Figure 7 is Figure 6 a schematic diagram of the combination structure of the swing rod and the ratchet pawl in;

[0044] In the figure, simulation box 100; carrier table 200; near-infrared spectrometer 300; optical fiber probe 310; linear moving mechanism 400; stepless speed regulation air pump 500; dust collector 610;

[0045] base plate 210; support ear 211; carrier plate 220; rotating shaft 230;

[0046] high-temperature resistant motor 410; screw rod 420; guide rod 430;

[0047] dust feeding mechanism 620; oil bath 710; heater 720;

[0048] air distribution plate 810; gas distribution cavity 820; dust collection chamber 830; dust through hole 840;

[0049] ratchet wheel 910; first ratchet pawl 921; first swing rod 930; second swing rod 940; second ratchet pawl 922; blocking rod 950; rope 960. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] Next, in combination with the accompanying drawings and specific embodiments, the present invention will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0051] Please refer to Figures 1 to 7 , which shows the structures of two specific embodiments of the experimental device for simulating the influence of the underground environment on the near-infrared spectrum of coal and rock of the present invention. The experimental device of the present invention is used to simulate the underground environment of coal and rock and obtain the near-infrared spectrum data of coal and rock samples in this environment, facilitating the correction of underground near-infrared spectrum data. The experimental device of the present invention includes a simulation box 100, a stage 200, a near-infrared spectrometer 300, an optical fiber probe 310, a rangefinder, a linear moving mechanism 400, a stepless speed regulation air pump 500, a dust collector 610, a dust feeding mechanism 620, and a temperature control mechanism, which can simulate various underground environmental factors, such as the distance between the optical fiber probe 310 and the coal and rock sample, the gas flow rate, the dust concentration in the gas, the relative moving speed between the optical fiber probe 310 and the coal and rock sample, and the temperature, etc.

[0052] The simulation box 100 of the present invention is of a closed structure. The stage 200 is located inside the simulation box 100 and is used to carry coal and rock samples. One end of the optical fiber probe 310 is connected to the near-infrared spectrometer 300, and the other end is inserted into the simulation box 100 from the top of the simulation box 100 and is hermetically connected to the wall surface of the simulation box 100. The optical fiber probe 310 includes an incident optical fiber and an outgoing optical fiber and is used to obtain the near-infrared spectrum data of coal and rock samples. The optical fiber probe 310 can move along its axis, so as to adjust the distance between the coal and rock sample and the optical fiber probe 310. The rangefinder is fixed at one end of the optical fiber probe 310 facing the coal and rock sample and faces the top surface of the coal and rock sample, and is used to measure the distance between the optical fiber probe 310 and the coal and rock sample. The linear moving mechanism 400 is used to push the stage 200 to move linearly along the horizontal plane, so as to change the relative speed between the optical fiber probe 310 and the coal and rock sample. The stepless speed regulation air pump 500 is used to drive the gas in the simulation box 100 to circulate, so as to adjust the gas flow rate between the coal and rock sample and the optical fiber probe 310. The dust collector 610 is used to remove dust from the circulating gas leaving the simulation box 100, and the dust feeding mechanism 620 is used to add dust to the circulating gas entering the simulation box 100, so as to adjust the dust concentration in the gas between the coal and rock sample and the optical fiber probe 310. The temperature control mechanism is used to control the temperature inside the simulation box 100, so as to simulate different underground temperatures.

[0053] The temperature control mechanism of the present invention is used to control the temperature inside the simulation box 100. The specific control means and equipment can be reasonably selected according to factors such as the scale of the experimental device. For example, a constant temperature box can be selected when the experimental device is relatively small. Also, for example, in some embodiments, in order to reduce temperature fluctuations, oil bath temperature control is selected, such as Figure 1As shown, the temperature control mechanism includes an oil bath 710 and a heater 720. Among them, the oil bath 710 stores heat-conducting oil, and the heater 720 adopts closed-loop control to stably control the temperature of the heat-conducting oil. The simulation box 100 is immersed in the oil bath 710, so that the temperature of the simulation box 100 can be controlled by the heat-conducting oil. Of course, if the volume of the oil bath 710 is large, a circulation pump can also be added to circulate the heat-conducting oil in the oil bath 710, so that the temperature in the entire oil bath 710 is more uniform.

[0054] The linear moving mechanism 400 of the present invention is used to push the stage 200 to move in the simulation box 100, and this function can be realized by a conventional telescopic mechanism. It should be noted that during the simulation experiment, dust in the gas may settle at the bottom of the simulation box 100, resulting in problems such as jamming, which may hinder the sliding of the stage 200 along the bottom surface of the simulation box 100. Therefore, in some embodiments, the stage 200 is suspended in the simulation box 100, that is, the bottom of the stage 200 is separated from the bottom of the simulation box 100, that is, there is a certain distance between the two, such as Figure 1 and Figure 3 As shown, at this time, the linear moving mechanism 400 needs to provide a horizontal thrust and a vertical supporting force to the stage 200, and at the same time, it is necessary to prevent the stage 200 from rotating, as Figure 2 As shown, the linear moving mechanism 400 includes a high-temperature-resistant motor 410, a screw 420 and a guide rod 430. Both ends of the screw are rotatably fixed in the simulation box 100, and the middle part of the screw 420 is threadedly connected to the stage 200. The output shaft of the high-temperature-resistant motor 410 is coaxially connected to the screw 420, so as to drive the screw 420 to rotate synchronously. The guide rod 430 is fixed in the simulation box 100 and is parallel to the screw 420. At the same time, the guide rod 430 passes through the stage 200 and has a clearance fit with it, so as to prevent the stage 200 from rotating.

[0055] The present invention adopts the method of first removing dust and then adding dust to accurately control the dust content in the gas entering the simulation box 100. Among them, the dust collector 610 can adopt a bag filter, and the dust feeding mechanism 620 can adopt a mature device such as a screw feeder conveyor.

[0056] In the present invention, after the gas enters the simulation box 100, its speed will decrease due to the increase in the flow cross-sectional area, which is likely to generate a dead zone (stagnant flow zone) in the simulation box 100, making it difficult to accurately measure the true gas flow rate between the optical fiber probe 310 and the coal and rock sample through the circulating gas flow. Therefore, in some embodiments, such as Figure 3 and Figure 4As shown, a wind distribution plate 810 is provided at the gas inlet end of the simulation chamber 100. The wind distribution plate 810 is vertically arranged and separated from the gas inlet of the simulation chamber 100, that is, there is a certain distance between the two, so as to form a gas distribution chamber 820 between the inner wall of the simulation chamber 100 and the wind distribution plate 810. A plurality of Z-shaped flow channels are arranged in an array on the wind distribution plate 810 to increase the gas flow resistance, which is beneficial to the uniform distribution of gas in these flow channels, and further reduces the dead zone volume in the simulation chamber 100. At the same time, the presence of the wind distribution plate 810 increases the pressure when the gas enters the simulation chamber 100 and also reduces the gas flow velocity at this place, which will increase the deposition tendency of dust in the gas and interfere with the measurement of the dust concentration. Therefore, in order to reduce the dust deposition amount, the gas inlet of the gas distribution chamber 820 is located at the bottom of the gas distribution chamber 820, that is, the gas outlet of the stepless speed regulation air pump 500 is communicated with the bottom of the gas distribution chamber 820, so that the gas flows upward from the bottom after entering the gas distribution chamber 820, hindering dust deposition.

[0057] In addition, dust will deposit and stack in the simulation chamber 100. Affected by the disturbance of the air flow at the bottom of the wind distribution plate 810, the dust thickness near the wind distribution plate 810 is lower, while the dust thickness far from the wind distribution plate 810 is higher. As the dust accumulates continuously, the dust thickness difference at each place will gradually increase and finally form a slump, that is, the dust at the higher thickness slides towards the lower dust thickness, which will move the dust far from the wind distribution plate 810 to a position closer to the wind distribution plate 810, so that some dust is disturbed by the strong air flow of the wind distribution plate 810 and enters the gas phase of the simulation chamber 100 again. Moreover, the larger the slump dust amount and the farther the horizontal movement distance of the dust during the slump, the larger the amount of dust entering the gas phase of the simulation chamber 100 again, and this amount is difficult to measure, thus greatly interfering with the measurement of the dust concentration in the gas. Therefore, in some embodiments, a dust collection chamber 830 is provided at the bottom of the simulation chamber 100, and dust through holes 840 are arranged in an array at the part of the bottom plate of the simulation chamber 100 outside the gas distribution chamber 820. The dust deposited in the simulation chamber 100 can enter the dust collection chamber 830 through the through holes 840. In this way, the maximum stacking height of the dust is also reduced, and the horizontal movement distance of the dust during the slump is also reduced, thereby reducing the amount of deposited dust entering the gas in the simulation chamber 100 again and reducing the influence on the dust concentration in the simulation chamber 100. In addition, the dust through holes 840 can be in the shape of inverted conical holes, so as to reduce the planar area at the bottom of the simulation chamber 100 and be more conducive to the rapid entry of dust into the simulation chamber 100.

[0058] In some embodiments, the top surface of the coal-rock sample can be prefabricated into curved surfaces or inclined surfaces at different angles to explore the influence of different incident light angles on the near-infrared spectrum. The top surface of the coal-rock sample can also be set as a flat surface, and different incident angles can be formed by adjusting the angle between the coal-rock sample and the stage 200. However, since the coal-rock sample is located in the simulation box 100, the existing method of adjusting the angle is often manual adjustment, which requires opening the simulation box 100, making the operation cumbersome and time-consuming. In view of this, the present invention proposes a new structure, which improves the stage 200 and cooperates with an angle adjustment mechanism to adjust the inclination angle of the coal-rock sample on the stage 200. It can adjust the inclination angle of the stage 200 through the linear movement mechanism 400 in a closed space, thus eliminating the step of opening the simulation box 100.

[0059] Specifically, please refer to Figures 3 to 7 , the stage 200 includes a base plate 210, a stage plate 220 and a rotating shaft 230. The stage plate 220 is used to carry the coal-rock sample. The base plate 210 is connected to the linear movement mechanism 400. Among them, the base plate 210 is provided with an ear 211 extending along the normal direction. The rotating shaft 230 is fixedly connected to the stage plate 220 and rotatably connected to the ear 211, so that the stage plate 220 is hinged to the base plate 210.

[0060] The angle adjustment mechanism includes a ratchet wheel 910, a first pawl 921, a first swing rod 930, a second swing rod 940, a second pawl 922 and a blocking rod 950. Among them, the ratchet wheel 910 is fixedly connected to the rotating shaft 230. Therefore, the ratchet wheel 910, the rotating shaft 230 and the load plate 220 will rotate synchronously, and the included angle between the base plate 210 and the load plate 220 can be adjusted by rotating the ratchet wheel 910; the ratchet wheel 910 is a disc structure with a one-way tooth groove on the outer edge; one end of the first pawl 921 is rotatably connected to the lug 211. At the same time, the first pawl 921 is equipped with an elastic element to push its free end to abut against the outer edge of the ratchet wheel 910 and mesh with the tooth groove of the ratchet wheel 910, so as to prevent the ratchet wheel 910 from reversing and play a check role; one end of the first swing rod 930 is rotatably connected to the rotating shaft 230, and one end of the second pawl 922 is rotatably connected to the first swing rod 930. At the same time, the second pawl 922 is equipped with an elastic element to push its free end to abut against the outer edge of the ratchet wheel 910 and mesh with the tooth groove of the ratchet wheel 910 to prevent the ratchet wheel 910 from reversing. Therefore, rotating the first swing rod 930 reciprocally can drive the ratchet wheel 910 to rotate unidirectionally; one end of the second swing rod 940 is rotatably connected to the base plate 210, and the free ends of the second swing rod 940 and the first swing rod 930 are respectively fixed at both ends of a rope 960 with a certain length, so as to link the two, and the rotation plane of the second swing rod 940 is perpendicular to the rotation plane of the first swing rod 930. The blocking rod 950 is horizontally fixed in the simulation box 100 and extends along the moving direction of the stage 200. At the same time, the center line of the blocking rod 950 is located on the rotation plane of the second swing rod 940; when the second swing rod 940 is separated from the blocking rod 950, the first swing rod 930 rotates reversely to the limit position under the action of the return spring and drives the free end of the second swing rod 940 to rotate reversely to a position higher than the blocking rod 950; when the stage 200 moves towards the blocking rod and continues to move in the same direction after the side wall of the second swing rod 940 abuts against the blocking rod 950, the blocking rod 950 pushes the second swing rod 940 to rotate forward. The second swing rod 940 drives the second swing rod 940 to rotate forward through the rope 960, and then drives the ratchet wheel 910 to rotate until the free end of the second swing rod 940 abuts against the annular outer wall of the blocking rod 950; similarly, when the stage 200 moves in the reverse direction (that is, along the direction away from the blocking rod 950), it will ultimately cause the second swing rod 940 to be separated from the blocking rod 950, and the first swing rod 930 will reset under the action of the return spring. Thus, the inclination angle of the top surface of the coal and rock sample can be adjusted by driving the second swing rod 940 to move and touch the blocking rod 950 through the linear moving mechanism 400, and the angle adjusted by each touch is equal.

[0061] During specific use, the linear movement mechanism 400 can drive the stage 200 to reciprocate, but the second swing rod 940 does not touch the blocking rod 950 to simulate the underground environment with speed as a single-factor variable. Alternatively, the linear movement mechanism 400 can drive the stage 200 to reciprocate and the second swing rod 940 touches the blocking rod 950 to simulate the underground environment with the incident angle as a single-factor variable. Through the linkage of the linear movement mechanism and the ratchet mechanism, the present invention realizes the automatic adjustment of the angle of coal and rock samples in a closed environment, solving the problem of low efficiency of traditional manual operation.

[0062] For those skilled in the art, according to the technical solutions and concepts described above, various corresponding changes and deformations can be made, and all such changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. An experimental device for simulating the influence of downhole environment on the near-infrared spectrum of coal and rock, characterized in that, Comprising: A simulation box with a closed structure; A stage located inside the simulation box for carrying coal and rock samples; A near-infrared spectrometer; An optical fiber probe with one end connected to the near-infrared spectrometer, the other end inserted into the simulation box from the top of the simulation box and sealingly connected to the wall surface of the simulation box. The optical fiber probe includes an incident optical fiber and an outgoing optical fiber, and is used to obtain the near-infrared spectral data of the coal and rock samples; the optical fiber probe can move along its axis; A rangefinder fixed at one end of the optical fiber probe facing the coal and rock samples and facing the top surface of the coal and rock samples; A linear movement mechanism for pushing the stage to move linearly along the horizontal plane; A stepless speed regulation air pump for driving the gas in the simulation box to circulate and flow; A dust collector for removing dust from the circulating gas leaving the simulation box; A dust feeding mechanism for adding dust to the circulating gas entering the simulation box; A temperature control mechanism for controlling the temperature inside the simulation box.

2. An experimental device for simulating the influence of downhole environment on the near-infrared spectrum of coal and rock, characterized in that, The temperature control mechanism includes an oil bath and a heater. Among them, heat-conducting oil is stored in the oil bath, and the heater adopts closed-loop control to stably control the temperature of the heat-conducting oil. The simulation box is immersed in the oil bath.

3. An experimental device for simulating the influence of underground environment on the near-infrared spectrum of coal and rock, characterized in that, The stage is suspended inside the simulation box. The linear movement mechanism includes: A screw rod fixed in the simulation box in a rotatable manner, and the middle part of the screw rod is threadedly connected to the stage; A guide rod fixed inside the simulation box and parallel to the screw rod. The guide rod passes through the stage and has a clearance fit with it; A high-temperature resistant motor with an output shaft coaxially connected to the screw rod.

4. An experimental device for simulating the influence of the underground environment on the near-infrared spectrum of coal and rock, characterized in that, A air distribution plate is arranged at the gas inlet end of the simulation box. The air distribution plate is vertically arranged and separated from the gas inlet of the simulation box, so as to form a gas distribution cavity between the inner wall of the simulation box and the air distribution plate. A plurality of Z-shaped flow channels are arranged in an array on the air distribution plate; the gas inlet of the gas distribution cavity is located at its bottom.

5. An experimental device for simulating the influence of underground environment on the near-infrared spectrum of coal and rock, characterized in that, A dust collection chamber is arranged at the bottom of the simulation box. Dust through holes are arranged in an array at the part of the bottom plate of the simulation box outside the gas distribution cavity. The simulation box is communicated with the dust collection chamber through the dust through holes.

6. An experimental device for simulating the influence of underground environment on the near-infrared spectrum of coal and rock, characterized in that, The dust through holes are inverted conical holes.

7. An experimental device for simulating the influence of the underground environment on the near-infrared spectrum of coal and rock, characterized in that, The stage includes a base plate, a loading plate and a rotating shaft. The base plate is connected to the linear movement mechanism. Among them, support ears extending in the normal direction are provided on the base plate. The rotating shaft is fixedly connected to the loading plate and rotatably connected to the support ears; The experimental device further includes an angle adjustment mechanism. The angle adjustment mechanism includes: A ratchet fixedly connected to the rotating shaft, which is a disc structure with a one-way tooth groove on the outer edge; A first pawl with one end rotatably connected to the support ear and the other end abutting against the outer edge tooth groove of the ratchet; A first swing rod with one end rotatably connected to the rotating shaft; A second pawl with one end rotatably connected to the first swing rod and the other end abutting against the outer edge tooth groove of the ratchet; A second swing rod with one end rotatably connected to the base plate. The free ends of the second swing rod and the first swing rod are respectively fixed at both ends of a rope, and the rotation planes of the second swing rod and the first swing rod are perpendicular to each other; A blocking rod horizontally fixed inside the simulation box, the blocking rod extending along the direction of the horizontal movement of the loading platform, and the center line of the blocking rod being located on the rotation plane of the second swing rod; Wherein, the first ratchet pawl and the second ratchet pawl prevent the ratchet wheel from rotating in the reverse direction. When the second swing rod is separated from the blocking rod, the first swing rod rotates in the reverse direction to the limit position under the action of the return spring and drives the free end of the second swing rod to rotate in the reverse direction to a position higher than the blocking rod; when the loading platform moves towards the blocking rod and continues to move in the same direction after the side wall of the second swing rod abuts against the blocking rod, the blocking rod pushes the second swing rod to rotate forward until the free end of the second swing rod abuts against the annular outer wall of the blocking rod.

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