Gas compression low-temperature compressed air discharged pulverized coal rapid sampling device and use method thereof

Abstract

The invention belongs to the technical field of coal seam drilling and sampling, and discloses a gas compression low-temperature compressed air discharged pulverized coal rapid sampling device and a using method thereof.The gas compression low-temperature compressed air discharged pulverized coal rapid sampling device comprises a refrigeration module, a drilling machine, a drilling rod, a three-way pipeline and a coal sample collecting tank, and the refrigeration module is connected with the input end of the drilling machine and used for preparing low-temperature gas; the refrigeration module comprises a gas compressor, a condenser and an expansion machine, the gas compressor collects gas to the inside for compression and pressurization, the compressed gas enters the condenser for heat exchange with the outside for cooling, the cooled gas enters the expansion machine for adiabatic expansion to do work externally for further cooling, and finally low-temperature gas is output; low-temperature gas reaches the bottom end of the drill hole through a hollow channel in the drill rod, is cooled, discharges a coal sample out of the drill hole by utilizing self power and is collected by a coal sample collecting tank; the coal seam pulverized coal sampling device solves the problems that in the prior art, the pulverized coal sampling process is troublesome, and coal sample oxidation and gas loss are easily caused in the sampling process, and is suitable for coal seam pulverized coal sampling.

Description

Technical Field

[0001] The invention relates to the technical field of coal seam drilling sampling, and in particular to a gas compression low-temperature compressed air exhaust coal powder rapid sampling device and a use method thereof. Background Art

[0002] The gas content of coal seams is an important indicator to measure the gas occurrence of coal seams. The gas content of coal seams is an important basic gas parameter, which provides a scientific basis for the resource exploration, evaluation and development of coal seam methane, and the prevention and control of mine gas disasters.

[0003] Due to the complex endowment of coal resources in my country, accurate evaluation and analysis of coalbed methane resources are necessary to ensure safe mining of mines and improve the efficiency of coalbed methane utilization. Accurate measurement of coalbed methane content is of great scientific significance for the implementation of green coal resource development. At present, the most widely used coalbed methane resource evaluation method in my country is the direct determination of coalbed methane content. The coal sampling coring technology, which is the basis of the direct determination of coalbed methane content, is also the focus of research by scholars at home and abroad.

[0004] As the most widely used and relatively accurate coal seam gas content determination method, the direct determination method mainly includes two categories: drilling cuttings method and core tube coal sampling. The drilling cuttings method is prone to coal sample oxidation, coal body temperature rise, and large coal dust in the working environment during the sampling process; the core tube coal sampling method is prone to friction between the core tube and the coal body, causing a large increase in the temperature of the coal sample, resulting in a large amount of gas escaping, and a long coring time, resulting in a large amount of gas loss. However, a large amount of gas desorption during the sampling process causes gas loss, which can easily lead to large errors in the determination results. Related simulations and low-temperature experiments show that the use of low-temperature suppression of gas desorption can greatly reduce gas loss. Summary of the invention

[0005] In order to improve the problems existing in the background technology, the present invention intends to provide a gas compression low-temperature compressed air exhaust coal powder rapid sampling device and its use method. The device does not need to withdraw the drill and replace the corer, which reduces the work tasks, improves work efficiency, greatly speeds up the sampling time of coal samples, and can drill to the bottom of the hole during construction, reduce the coal sample to a low temperature in a relatively short time, and use the low temperature to inhibit gas desorption, promote the adsorption of free gas, reduce the gas loss of the coal body, improve the accuracy of the estimated gas loss of the coal body, reduce the oxidation degree of the coal sample, and reduce the gas loss, thereby improving the accuracy of the determination of the gas content in the coal seam.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A gas compression low-temperature compressed air exhaust coal powder fast sampling device, comprising a refrigeration module, a drilling rig, a three-way pipeline, a drill rod and a coal sample collection tank, the refrigeration module comprising a gas compressor, a condenser and an expander connected in sequence through pipelines, the gas compressor output end is connected to a pressure sensor, the pressure sensor controls the switch of the gas compressor output end according to the pressure, the expander input end is provided with a regulating valve, the regulating valve is used to adjust the gas flow rate, the expander output end is connected to a first temperature sensor, the first temperature sensor controls the switch of the expander output end according to the temperature, the drilling rig input end is connected to the expander output end through a pipeline, the pipeline connection between the drilling rig and the expander is provided with a three-way valve, the three-way valve is provided at the pipeline connection between the drilling rig and the expander, and the three-way valve is provided at the pipeline connection between the drilling rig and the expander. The through valve is also connected to a water pump. The three-way valve is used to control the device selected to be connected to the drilling rig. The output end of the drilling rig is sealed and connected to the three-way pipe. The three-way pipe is connected to the blowout prevention device. The two sides of the three-way pipe are connected to the coal sample collection tank through pipes. The coal sample collection tank is detachably connected to the pipe. The first solenoid valve and the second solenoid valve are arranged on both sides of the three-way pipe. Several second temperature sensors are arranged in the blowout prevention device. The second temperature sensor is used to control the first solenoid valve and the second solenoid valve. The output end of the drilling rig is connected to the drill rod through a thread. The three-way pipe is located on the outside of the drill rod. A hollow channel for conveying low-temperature gas is arranged inside the drill rod. A drill bit is connected to the end of the drill rod, and a gas transmission hole connected to the hollow channel is arranged on the drill bit.

[0008] Furthermore, the pipeline between the gas compressor and the condenser is a high-temperature and high-pressure pipeline that can withstand high temperature and high pressure, a one-way valve is provided on the pipeline between the condenser and the expander, and the pipeline between the expander and the drilling rig input end is a low-temperature pipeline that can withstand low temperature.

[0009] Through the above-mentioned configuration, it can be better ensured that the device can work safely and stably. The gas discharged from the gas compressor is in a high-temperature and high-pressure state, and is transported using a high-temperature and high-pressure pipeline that can withstand high temperature and high pressure. The one-way valve can prevent the cooling gas from flowing back. The gas discharged from the expander is in a low-temperature state and is transported using a low-temperature pipeline that can withstand low temperature.

[0010] Furthermore, the gas compressor is a piston compressor, the compressor is directly driven by an electric motor, and an air filter (muffler) is provided on the air intake valve of the gas compressor.

[0011] Through the above arrangement, the motor directly drives the compressor, causing the crankshaft to rotate, driving the connecting rod to make the piston reciprocate, causing the cylinder volume to change. Due to the change in pressure in the cylinder, the gas enters the cylinder from the intake valve through the air filter. During the compression process, after reaching a certain pressure, the pressure sensor opens, and the compressed gas enters the condenser through a high-temperature and high-pressure pipeline.

[0012] Furthermore, a pressure gauge is installed on the gas compressor, and the pressure gauge is used to monitor the internal pressure of the gas compressor in real time.

[0013] Through the above-mentioned setting, the gas pressure inside the gas compressor can be observed in real time, which makes it convenient to control the compressed gas within the set range, thereby saving efficiency and ensuring construction safety.

[0014] Furthermore, the refrigerant inputted into the input end of the gas compressor is R134A gas refrigerant.

[0015] Through the above settings, the use of R134A gas refrigerant is more environmentally friendly and safer.

[0016] A gas compression low temperature compressed air exhaust coal powder fast sampling device, the use method of which comprises the following steps:

[0017] S1. Check whether the gas transportation is smooth: connect the gas compressor, condenser, expander and drilling rig through pipelines, turn on all devices in the refrigeration module after connection, turn the three-way valve to connect the expander output end with the drilling rig input end, and check whether the gas can reach the gas transmission hole to determine whether it is smooth. If it is smooth, proceed to the next step, otherwise, check and repair;

[0018] S2, perform coal seam drilling operation, turn the three-way valve to connect the water pump output end with the drilling rig input end, fix the three-way pipe together at the borehole through the blowout prevention device, turn on the water pump and the drilling rig to start drilling, the flushing liquid temperature is higher than the set temperature of the second temperature sensor, the first solenoid valve is opened, the second solenoid valve is closed, and the flushing liquid is discharged from the pipeline;

[0019] S3. Stop drilling after the drilling rig reaches a certain distance from the set coal seam depth.

[0020] S4. At this time, all devices in the refrigeration module are turned on, so that low-temperature gas is discharged from the gas transmission hole, and the drill bit is cooled by the low-temperature gas. At the same time, the residual coal powder at the non-target depth is discharged. At this time, the temperature of the discharged coal powder cannot drop quickly to a temperature lower than the temperature of the second temperature sensor. When passing through the second temperature sensor, the first solenoid valve is opened, the second solenoid valve is closed, and the residual coal powder at the non-target depth is collected in the coal sample collection tank corresponding to the first solenoid valve;

[0021] S5. Due to the continuous refrigeration and cooling of the low-temperature gas, after the drilling rig continues to drill to the target depth, under the action of the low-temperature gas, the temperature of the coal sample at the target depth drops to a temperature lower than that of the second temperature sensor. When passing through the second temperature sensor, the first solenoid valve is closed and the second solenoid valve is opened, and the coal sample of the target coal seam is collected in the coal sample collection tank corresponding to the second solenoid valve.

[0022] Principle of the technical solution: In this solution, the gas compressor is directly driven by an electric motor, causing the crankshaft to rotate, driving the connecting rod to make the piston reciprocate, causing the cylinder volume to change. Due to the change in the pressure in the cylinder, the R134A gas refrigerant enters the cylinder through the air filter (muffler) through the intake valve of the gas compressor. During the piston compression process, the cylinder volume is reduced and the internal gas pressure increases. After the compressed gas pressure reaches the target value set by the pressure sensor, the valve at the output end of the gas compressor opens, and the compressed refrigerant enters the condenser; in the condenser, the compressed gas is cooled by heat exchange with the outside world; after cooling, it is discharged from the output end of the condenser into the expander. A regulating valve is set at the input end of the expander. The regulating valve controls the gas flow rate to improve efficiency. After entering the expander, the gas undergoes adiabatic expansion to do work externally and consumes the internal energy of the gas itself, thereby further cooling it. After the temperature drops to the setting value of the first temperature sensor, the valve at the output end of the expander opens to discharge the low-temperature gas. Low-temperature gas is discharged from the gas delivery hole through the hollow channel, and the discharged low-temperature gas is used for cooling. At the same time, the power of the low-temperature gas itself flushes the coal sample from the bottom of the hole to the hole mouth, and the coal sample is finally collected in the coal sample collection tank through the three-way pipe. At the same time, a second temperature sensor is set in the three-way pipe. When the liquid or non-target coal sample passes through the second sensor, the temperature is higher than the setting value of the second temperature sensor, the first solenoid valve opens, the second solenoid valve closes, and the liquid or non-target coal sample is discharged or collected. When the target coal sample that has been continuously cooled passes through the second temperature sensor, the temperature is lower than the setting value of the second temperature sensor, the first solenoid valve closes, the second solenoid valve opens, and the target coal sample is collected in the coal sample collection tank.

[0023] The beneficial effects of the technical solution are:

[0024] 1. The refrigeration module of the present invention selects R134A as the refrigerant. The refrigerant is an environmentally friendly material, will not damage the ozone layer, is non-flammable and non-explosive, non-toxic, has good safety performance, and has a good refrigeration effect.

[0025] 2. The present invention uses the low-temperature gas power provided by the refrigeration module as a way to obtain coal samples. The R134A gas refrigerant is compressed, condensed, and adiabatically expanded to obtain low-temperature gas. The low-temperature gas reaches the gas delivery hole at the front end of the drill bit through the hollow channel inside the drill pipe, thereby reaching the bottom of the hole and then using the power of the low-temperature gas itself to deliver the required coal sample to the hole mouth. Therefore, the device does not need to withdraw the drill and replace the corer, which reduces the work tasks, improves work efficiency, and greatly speeds up the sampling time of coal samples.

[0026] 3. The low temperature of the low-temperature gas of the present invention can reduce the temperature of the coal sample, reduce the degree of oxidation of the coal sample, and reduce the amount of gas loss, thereby improving the accuracy of the determination of the gas content in the coal seam. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the overall structure diagram of the present invention;

[0028] Figure 2 This is a diagram showing the internal structure of the three-way pipeline of the present invention;

[0029] The names of corresponding marks in the accompanying drawings are: refrigeration module 1, drilling rig 2, three-way pipeline 3, drill rod 4, coal sample collection tank 5, gas compressor 6, condenser 7, expander 8, water pump 9, high-temperature and high-pressure pipeline 11, one-way valve 12, low-temperature pipeline 13, three-way valve 14, blowout preventer 31, first solenoid valve 32, second solenoid valve 33, second temperature sensor 34, hollow channel 41, drill bit 42, gas transmission hole 43, pressure sensor 61, pressure gauge 62, regulating valve 81, first temperature sensor 82. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0031] like Figure 1 As shown, a gas compression low-temperature compressed air exhaust coal powder fast sampling device includes a refrigeration module 1, a drilling rig 2, a three-way pipeline 3, a drill rod 4 and two coal sample collection tanks 5. The refrigeration module 1 includes a gas compressor 6, a condenser 7 and an expander 8 connected in sequence through pipelines. The gas compressor 6 is a piston compressor, which is directly driven by an electric motor, and an air filter (muffler) is provided on the air inlet valve of the gas compressor 6. A pressure gauge 62 is provided on the gas compressor 6. The pressure gauge 62 is used to monitor the internal pressure of the gas compressor 6. A pressure sensor 61 is provided at the output end of the gas compressor 6. The pressure sensor 61 controls the gas compression according to the pressure. The output end of the gas compressor 6 is connected to the input end of the condenser 7 through a high-temperature and high-pressure pipeline 11, and the output end of the condenser 7 is connected to the input end of the expander 8 through a pipeline, and a one-way valve 12 is provided on the pipeline. The input end of the expander 8 is provided with a regulating valve 81, and the regulating valve 81 is used to adjust the gas flow. The output end of the regulating valve 81 is connected to a first temperature sensor 82, and the first temperature sensor 82 controls the switch of the output end of the expander 8 according to the temperature. The output end of the expander 8 is connected to the input end of the drilling rig 2 through a low-temperature pipeline 13, and a three-way valve 14 is provided on the low-temperature pipeline 13. The other end of the three-way valve 14 is connected to the water pump 9 through a pipeline;

[0032] The output end of the drilling rig 2 is tightly connected to the drill rod 4 through a threaded structure, and the output end of the drilling rig 2 is sealed and connected to the three-way pipe 3. The three-way pipe 3 is located outside the drill rod 4, and the drill rod 4 is penetrated by the three-way pipe 3. The front end of the three-way pipe 3 is connected to a blowout prevention device 31, and the blowout prevention device 31 is a funnel-shaped structure that can fit the sealed borehole. A second temperature sensor 34 is arranged inside the three-way pipe 3, and two coal sample collection tanks 5 are connected on both sides of the three-way pipe 3 through pipes. A first solenoid valve 32 and a second solenoid valve 33 are arranged inside the three-way pipe 3. The first solenoid valve 32 and the second solenoid valve 33 are connected to each other. The two solenoid valves 33 control the two coal sample collection tanks 5 respectively, and the second temperature sensor 34 controls the first solenoid valve 32 and the second solenoid valve 33. When the temperature is higher than the set value of the second temperature sensor 34, the first solenoid valve 32 opens and the second solenoid valve 33 closes. When the temperature is lower than the set value of the second temperature sensor 34, the first solenoid valve 32 closes and the second solenoid valve 33 opens. A hollow channel 41 is arranged inside the drill rod 4, and a drill bit 42 is connected to the front end of the drill rod 4. A gas supply hole 43 is arranged on the drill bit 42, and the gas supply hole 43 is connected to the hollow channel 41.

[0033] The specific implementation process is as follows:

[0034] The process of preparing low-temperature gas by the refrigeration module: the gas compressor 6 is directly driven by the electric motor to make the crankshaft rotate, drive the internal connecting rod to make the piston reciprocate, and cause the cylinder volume to change. Due to the change in the cylinder volume, the pressure also changes, so that the R134A gas refrigerant enters the cylinder through the air filter (muffler) at the input end of the gas compressor 6. During the compression process, the cylinder volume decreases and the internal pressure increases. After the internal pressure increases to the set value of the pressure sensor 61, the pressure sensor 61 controls the valve at the output end of the gas compressor 6 to open, and the compressed gas passes through the high-temperature and high-pressure pipeline 11. The compressed gas is input into the condenser 7, where the compressed gas is cooled by exchanging heat with the outside. The cooled gas is transported from the output end of the condenser 7 to the input end of the expander 8 via a pipeline. A one-way valve 12 is provided on the pipeline to prevent gas backflow. A regulating valve 81 is provided at the input end of the expander 8 to adjust the gas flow rate, thereby improving efficiency. After the gas enters the expander 8, it undergoes adiabatic expansion to do work externally, consuming the internal energy of the gas itself, thereby further cooling the gas. After the first temperature sensor 82 detects that the temperature has dropped to the set value, the first temperature sensor 82 controls the valve at the output end of the expander 8 to open, thereby outputting low-temperature gas.

[0035] Process of coal powder sampling:

[0036] Step 1: Check whether the gas transportation is smooth: connect the gas compressor 6, condenser 7, expander 8 and drilling rig 2 through pipelines, turn the three-way valve 14 to connect the output end of the expander 8 with the input end of the drilling rig 2, and then turn on all devices in the refrigeration module 1. Check whether the low-temperature gas can reach the gas transmission hole 43 to determine whether it is smooth. If it is smooth, proceed to the next step. If it is not smooth, check and repair it;

[0037] Step 2: Perform coal seam drilling operation, rotate the three-way valve 14 to connect the output end of the water pump 9 with the input end of the drilling rig 2, fix the three-way pipe 3 together at the borehole through the blowout prevention device 31, start the water pump 9 and the drilling rig 2 to start drilling, the temperature of the flushing liquid is higher than the set temperature of the second temperature sensor 34, the first solenoid valve 32 is opened, the second solenoid valve 33 is closed, the coal sample collection tank 5 at the first solenoid valve 32 is disassembled, and the flushing liquid is discharged from the pipeline;

[0038] Step 3: Stop drilling after the drilling rig 2 has drilled to a certain distance from the set coal seam depth.

[0039] Step 4: Turn on all devices in the refrigeration module 1, so that low-temperature gas is discharged from the gas delivery hole 43, and the drill bit 42 is cooled by the low-temperature gas, and the residual coal powder at the non-target depth is discharged at the same time. At this time, the temperature of the discharged coal powder cannot drop quickly to a temperature lower than the temperature of the second temperature sensor 34. When passing through the second temperature sensor 34, the first solenoid valve 32 is opened, and the second solenoid valve 33 is closed, and the residual coal powder at the non-target depth is collected in the coal sample collection tank 5 corresponding to the first solenoid valve 32;

[0040] Step 5. Due to the continuous cooling and cooling of the low-temperature gas, after the drilling rig 2 continues to drill to the target depth, under the action of the low-temperature gas, the coal sample temperature at the target depth drops to a temperature lower than the temperature of the second temperature sensor 34. When passing through the second temperature sensor 34, the first solenoid valve 32 is closed and the second solenoid valve 33 is opened. The coal sample of the target coal seam is collected in the coal sample collection tank 5 corresponding to the second solenoid valve 33.

[0041] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A gas compression low temperature compressed air exhaust coal powder rapid sampling device, characterized in that: The invention comprises a refrigeration module (1), a drilling rig (2), a three-way pipeline (3), a drill rod (4) and a coal sample collection tank (5). The refrigeration module (1) comprises a gas compressor (6), a condenser (7) and an expander (8) which are connected in sequence through pipelines. The output end of the gas compressor (6) is connected to a pressure sensor (61). The pressure sensor (61) controls the switch of the output end of the gas compressor (6) according to the pressure. The input end of the expander (8) is provided with a regulating valve (81). The regulating valve (81) is used to adjust the gas flow rate. The output end of the expander (8) is connected to a first temperature sensor (82). The first temperature sensor (82) controls the switch of the output end of the expander (8) according to the temperature. The input end of the drilling rig (2) is connected to the output end of the expander (8) through a pipeline. A three-way valve (14) is provided at the connection between the pipeline of the drilling rig (2) and the expander (8). The three-way valve (14) is also connected to a water pump (9). The three-way valve (14) is used to control the A device connected to the drilling rig (2) is selected, the output end of the drilling rig (2) is sealedly connected to the three-way pipe (3), the three-way pipe (3) is connected to a blowout prevention device (31), both sides of the three-way pipe (3) are connected to the coal sample collection tank (5) through pipes, the coal sample collection tank (5) is detachably connected to the pipe, a first solenoid valve (32) and a second solenoid valve (33) are arranged on both sides of the three-way pipe (3), and a plurality of second temperature sensors (34) are arranged in the blowout prevention device (31). The second temperature sensor (34) is used to control the first solenoid valve (32) and the second solenoid valve (33); the output end of the drilling rig (2) is connected to the drill rod (4) via a thread; the three-way pipe (3) is located outside the drill rod (4); a hollow channel (41) for conveying low-temperature gas is provided inside the drill rod (4); a drill bit (42) is connected to the end of the drill rod (4); and a gas delivery hole (43) communicating with the hollow channel (41) is provided on the drill bit (42).

2. A gas compression low temperature compressed air exhaust coal powder rapid sampling device according to claim 1, characterized in that: The pipeline between the gas compressor (6) and the condenser (7) is a high-temperature and high-pressure pipeline (11) capable of withstanding high temperature and high pressure, a one-way valve (12) is provided on the pipeline between the condenser (7) and the expander (8), and the pipeline between the expander (8) and the input end of the drilling rig (2) is a low-temperature pipeline (13) capable of withstanding low temperature.

3. The gas compression low temperature compressed air exhaust coal powder rapid sampling device according to claim 1 is characterized by: The gas compressor (6) is a piston compressor, which is directly driven by an electric motor, and an air filter (muffler) is provided on the air intake valve of the gas compressor (6).

4. The device for rapid sampling of coal powder discharged by gas compression and low temperature compressed air according to claim 1 is characterized in that: The gas compressor (6) is provided with a pressure gauge (62), and the pressure gauge (62) is used to monitor the internal pressure of the gas compressor (6) in real time.

5. The device for rapid sampling of coal powder discharged by gas compression and low temperature compressed air according to claim 1 is characterized in that: The refrigerant input into the input end of the gas compressor (6) is R134A gas refrigerant.

6. A gas compression low temperature compressed air exhaust coal powder rapid sampling device according to any one of claims 1 to 4, wherein the method of using the device comprises the following steps: S1. Check whether the gas transportation is smooth: connect the gas compressor (6), condenser (7), expander (8) and drilling rig (2) through pipelines. After the connection, turn on all devices in the refrigeration module (1), turn the three-way valve (14) to connect the output end of the expander (8) with the input end of the drilling rig (2), and check whether the gas can reach the gas transmission hole (43) to determine whether it is smooth. If it is smooth, proceed to the next step. If it is not smooth, check and repair it; S2, performing coal seam drilling operation, rotating the three-way valve (14) to connect the output end of the water pump (9) with the input end of the drilling rig (2), fixing the three-way pipe (3) together at the drilling location through the blowout prevention device (31), turning on the water pump (9) and the drilling rig (2) to start drilling, the temperature of the flushing liquid is higher than the set temperature of the second temperature sensor (34), the first solenoid valve (32) is opened, the second solenoid valve (33) is closed, and the flushing liquid is discharged from the pipe; S3, when the drilling machine (2) has drilled to a certain distance from the set coal seam depth, the drilling is stopped; S4. At this time, all devices in the refrigeration module (1) are turned on, so that low-temperature gas is discharged from the gas transmission hole (43), and the drill bit (42) is cooled by the low-temperature gas. At the same time, the residual coal powder at the non-target depth is discharged. At this time, the temperature of the discharged coal powder cannot drop quickly to a temperature lower than the temperature of the second temperature sensor (34). When passing through the second temperature sensor (34), the first solenoid valve (32) is opened, and the second solenoid valve (33) is closed. The residual coal powder at the non-target depth is collected in the coal sample collection tank (5) corresponding to the first solenoid valve (32); S5. Due to the continuous cooling and cooling of the low-temperature gas, after the drilling rig (2) continues to drill to the target depth, under the action of the low-temperature gas, the temperature of the coal sample at the target depth drops to a temperature lower than the temperature of the second temperature sensor (34). When passing through the second temperature sensor (34), the first solenoid valve (32) is closed and the second solenoid valve (33) is opened, and the coal sample of the target coal seam is collected in the coal sample collection tank (5) corresponding to the second solenoid valve (33).

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