A sampling device for detecting gas concentration in mines

Abstract

The present invention discloses a sampling device for detecting gas concentration in a mine, comprising a sampling sleeve and a first piston rod, a first spring disposed between the first piston rod and the sampling sleeve, a limit assembly disposed at the top of the sampling sleeve, a second piston rod movably connected thereto disposed within the first piston rod, the first piston rod movably mounted within the sampling sleeve, a limit assembly comprising a limit pressure rod, a rotating shaft, a torsion spring, and a sealing cover, the limit assembly being mounted at the top of the sampling sleeve to limit the movement of the first piston rod, an air inlet nozzle disposed at the bottom of the sampling sleeve, an exhaust nozzle communicating with the air inlet nozzle disposed at the bottom of the side end surface of the sampling sleeve, and a movably connected valve stem disposed at the bottom of the side end surface of the sampling sleeve. The present invention has the advantages of simple structure, convenient operation, and the ability to perform sampling and pre-exhaust operations with one hand, thereby resolving the problems of existing devices such as complex valves, inconvenient operation, easy misoperation, and the limitation of two-handed operation on-site adjustment.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sampling devices, in particular to a sampling device for detecting gas concentration in mines. Background Art

[0002] In complex environments like mines, accurate gas concentration detection is crucial for ensuring operational safety and preventing gas explosions and toxic gas leaks. Gas sampling, a key step in the detection process, directly impacts the reliability of subsequent analysis results. Existing mine gas concentration detection and sampling devices commonly suffer from the following problems:

[0003] First, the valve structure of existing devices is usually complex and cumbersome to operate. An adjustment operation must be performed every time air is inhaled and exhausted, which is prone to misoperation and reduces work efficiency and safety. Secondly, the sampling device must be connected to the filter hose to remove particulate impurities in the air. Most existing sampling devices require two hands to operate, which increases the difficulty of operation on the one hand and limits the operator's ability to adjust the filter hose during the sampling process on the other hand, making it inconvenient to adjust the sampling position and affecting the overall work efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a sampling device for mine gas concentration detection, which has the advantages of simple structure, convenient operation, and sampling and pre-exhaust operations can be completed with one hand, solving the problems of complex valves, inconvenient operation, easy misoperation and two-handed operation limiting on-site adjustment of existing devices.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a sampling device for detecting gas concentration in a mine, comprising a sampling sleeve and a first piston rod, a first spring being provided between the first piston rod and the sampling sleeve, a limit assembly being provided at the top of the sampling sleeve, and a second piston rod being movably connected thereto being provided within the first piston rod;

[0006] The first piston rod is movably installed in the sampling sleeve, the limiting assembly includes a limiting pressure rod, a rotating shaft, a torsion spring and a sealing cover, the limiting assembly is installed on the top of the sampling sleeve to limit the movement of the first piston rod, the bottom of the sampling sleeve is provided with an air inlet nozzle, the bottom of the side end surface of the sampling sleeve is provided with an exhaust nozzle that is connected to the air inlet nozzle, and the bottom of the side end surface of the sampling sleeve is provided with a movably connected valve stem;

[0007] The limiting pressure rod includes a connecting portion, a limiting portion and a pressing portion, wherein the limiting portion is fixedly mounted on the top of the connecting portion, the pressing portion is fixedly mounted on the bottom of the connecting portion, and a rotating shaft rotatably connected to the ear plate is provided at the bottom of the side end of the connecting portion;

[0008] The top edge of the first piston rod is provided with a limiting flange, the left and right sides of the limiting portion are provided with rotatably connected rollers, and the top lower end surface of the first piston rod is provided with an annular recessed groove that cooperates with the first spring;

[0009] The first piston rod includes a first piston head and a first vertical rod, the top of the first vertical rod is provided with a piston cavity that passes through the bottom of the first vertical rod, the second piston rod includes a second piston head, a second vertical rod and a limit plate, the second piston head is installed in the piston cavity and is slidably connected to the second piston head, the second vertical rod is fixedly installed on the top of the second piston head, and the limit portion is fixedly installed on the top of the first vertical rod;

[0010] The bottom of the second piston head is provided with an exhaust plug that is slidably matched with the air inlet nozzle, and a finger ring is provided on the top of the limit plate.

[0011] As a preferred sampling device for mine gas concentration detection of the present invention, a valve hole is provided at the bottom of the side end face of the sampling sleeve, a sampling sleeve damping rotation connecting valve stem is provided in the valve hole, the upper end of the valve stem is provided with an air inlet hole connected to the lower end face, and the side end face of the valve stem is provided with an exhaust hole connected to the air inlet hole.

[0012] As a preferred sampling device for detecting gas concentration in a mine of the present invention, a shift rod is provided at the side end of the valve stem, and a fixed sleeve with an interference fit is provided at the end of the valve stem away from the shift rod.

[0013] As a preferred sampling device for mine gas concentration detection of the present invention, the inner end face of the air inlet nozzle has only a fixedly connected first limiting ring, the lower end of the first limiting ring is provided with a second spring and a first ball, and the bottom of the inner end face of the air inlet nozzle is a conical structure.

[0014] As a preferred sampling device for mine gas concentration detection of the present invention, the outer end face of the exhaust nozzle is provided with an external thread, the bottom of the sampling sleeve is provided with an exhaust interface, the inner end face of the exhaust interface is provided with an internal thread matching the exhaust nozzle, a second limiting ring and a third limiting ring are provided in the exhaust nozzle, and a third spring and a second ball are provided between the second limiting ring and the third limiting ring.

[0015] As a preferred sampling device for mine gas concentration detection of the present invention, the top of the sampling sleeve is provided with an external thread, the inner end face of the sealing cover is provided with an internal thread cooperating with the sampling sleeve, the center of the sealing cover is provided with a sliding hole cooperating with the first piston rod, the side end face of the sealing cover is provided with an ear plate, the limiting pressure rod is provided with a torsion spring, and the limiting pressure rod is installed on the ear plate and is elastically rotatably connected to it through the torsion spring.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention realizes fast and intuitive switching of gas channel modes through the T-shaped three-way hole formed by the air inlet and exhaust holes inside the valve stem and its rotatable structure, combined with the pointing function of the external lever. The operator only needs to simply rotate the valve stem to accurately control the on-off combination of the air inlet nozzle and the exhaust nozzle to achieve four working states: one-way air intake, one-way exhaust, complete sealing or free flow. This effectively solves the problems of cumbersome valve operation, unclear switching and easy error in traditional sampling devices. Especially in narrow and poorly lit mine environments, the pointing of the lever can clearly indicate the current mode, greatly improving the convenience and accuracy of operation. At the same time, the valve stem is firmly installed in the valve hole through a fixed shaft sleeve, avoiding accidental falling off during operation and ensuring the reliability of the equipment.

[0018] 2. The present invention provides secondary protection through the one-way valve structure provided for the air inlet nozzle and the exhaust nozzle respectively, thereby realizing strict one-way gas flow control. The one-way valve of the air inlet nozzle ensures that the gas can only be inhaled and not backflowed, and the one-way valve of the exhaust nozzle ensures that the gas can only be discharged and not inhaled. Combined with the completely sealed state of the valve stem, double protection is formed. First, it prevents external dust-containing air or impurities from flowing back through the exhaust nozzle during exhaust or idle time to contaminate the collected samples or the inside of the equipment; second, it prevents gas leakage or contamination in the sampling sleeve due to unexpected air pressure changes before and after sampling, especially in dusty mine environments. In addition, the exhaust nozzle adopts a threaded connection design, which is convenient for thorough blowing and cleaning after disassembly, further ensuring the cleanliness and measurement accuracy for long-term use.

[0019] 3. The present invention achieves efficient one-handed operation through the clever integration of a limit assembly and a nested second piston rod structure. The limit pressure rod automatically locks the first piston rod under the action of a torsion spring. After the lock is released, the first spring can instantly bounce the first piston rod to complete the main sampling. In the locked state, the second piston rod can be repeatedly pulled and drawn by one hand. The piston chamber and the emptying plug are designed so that when the second piston rod is pulled, external gas enters the piston chamber through the air inlet nozzle one-way valve, and then pushes the original gas in the piston chamber to be discharged through the exhaust nozzle one-way valve, forming a small circulation. This solves the key problem of non-sample gas pre-stored in the dead space inside the equipment contaminating the real sample. The representativeness and detection accuracy of the subsequent main sampling gas are significantly improved through the pre-exhaust operation, and the entire process does not require the assistance of the other hand. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 An exploded view of the present invention;

[0022] Figure 3This is a schematic diagram of the cross-sectional structure of the present invention from a first viewing angle;

[0023] Figure 4 is a schematic cross-sectional structural diagram of the present invention from a second viewing angle;

[0024] Figure 5 This is a schematic structural diagram of the sampling sleeve of the present invention;

[0025] Figure 6 For the present invention Figure 3 Enlarged view of point A in the middle;

[0026] Figure 7 For the present invention Figure 4 Enlarged view of point B in the middle;

[0027] Figure 8 This is a schematic structural diagram of the second piston rod of the present invention;

[0028] Figure 9 Schematic diagram of the valve stem structure of the present invention;

[0029] Figure 10 This is a schematic structural diagram of the first piston rod of the present invention;

[0030] Figure 11 It is a schematic diagram of the limit pressure rod structure of the present invention.

[0031] Figure: 1. Sampling sleeve; 101. Inlet nozzle; 102. Exhaust port; 103. Valve hole; 104. First stop ring; 105. Second spring; 106. First ball; 2. First piston rod; 201. Annular flange; 202. Annular groove; 203. Piston chamber; 204. First vertical rod; 205. First piston head; 3. Second piston rod; 301. Second piston head; 302. Second vertical rod; 303. Drain plug; 304. Stop plate; 305. Finger ring; 4. Stop assembly ;401, limiting pressure rod; 4011, connecting part; 4012, limiting part; 4013, pressing part; 4014, rotating shaft; 4015, roller; 403, torsion spring; 405, sealing cover; 406, sliding hole; 407, ear plate; 5, valve stem; 501, exhaust hole; 502, air inlet; 503, shift rod; 504, fixed sleeve; 6, exhaust nozzle; 601, second limiting ring; 602, third limiting ring; 603, second ball; 605, third spring; 7, first spring. DETAILED DESCRIPTION

[0032] Example 1

[0033] See also Figures 1-11A sampling device for detecting gas concentration in a mine comprises a sampling sleeve 1 and a first piston rod 2. A first spring 7 is provided between the first piston rod 2 and the sampling sleeve 1. A limit assembly 4 is provided on the top of the sampling sleeve 1. A second piston rod 3 is movably connected to the first piston rod 2.

[0034] The first piston rod 2 is movably installed in the sampling sleeve 1. The limit assembly 4 includes a limit pressure rod 401, a rotating shaft 4014, a torsion spring 403 and a sealing cover 405. The limit assembly 4 is installed at the top of the sampling sleeve 1 to limit the movement of the first piston rod 2. The bottom of the sampling sleeve 1 is provided with an air inlet nozzle 101, and the bottom of the side end surface of the sampling sleeve 1 is provided with an exhaust nozzle 6 that passes through the air inlet nozzle 101. The bottom of the side end surface of the sampling sleeve 1 is provided with a movably connected valve stem 5.

[0035] Furthermore, a valve hole 103 is provided at the bottom of the side end face of the sampling sleeve 1, and a valve stem 5 for damping rotation of the sampling sleeve 1 is provided in the valve hole 103. The upper end of the valve stem 5 is provided with an air inlet hole 502 which is connected to the lower end face, and the side end face of the valve stem 5 is provided with an exhaust hole 501 which is connected to the air inlet hole 502.

[0036] Since the air inlet nozzle 101 is usually connected to an external filter when sampling to filter out particulate impurities, in order to prevent particulate impurities from being blown into the detection equipment during exhaust, the gas usually flows in one direction from the air inlet nozzle 101 into the exhaust nozzle 6 and out. The air inlet hole 502 and the exhaust hole 501 form a T-shaped three-way hole in the valve stem 5. The connection and disconnection of the air inlet nozzle 101 and the exhaust nozzle 6 are controlled by rotating the valve stem 5. When the air inlet hole 502 is vertical and the exhaust hole 501 is facing away from the exhaust nozzle 6, the air flow can only enter the sampling sleeve 1 through the air inlet nozzle 101. When When the air inlet 502 is horizontal and the exhaust hole 501 is upward, the air flow in the sampling sleeve 1 can only be discharged from the exhaust nozzle 6. When the air inlet 502 is horizontal and the exhaust hole 501 is downward, the air inlet nozzle 101 and the exhaust nozzle 6 are all blocked, thereby preventing gas leakage in the sampling sleeve 1. When the air inlet 502 is vertical and the exhaust hole 501 is facing the exhaust nozzle 6, the air inlet nozzle 101 and the exhaust nozzle 6 are both connected to the inside of the sampling sleeve 1, and air can flow in and out freely, which is used to empty the non-sample gas pre-stored in the air inlet nozzle 101 and the exhaust nozzle 6.

[0037] Furthermore, a shift rod 503 is provided at the side end of the valve stem 5 , and a fixed shaft sleeve 504 with an interference fit is provided at the end of the valve stem 5 away from the shift rod 503 .

[0038] The valve stem 5 can be easily moved by the lever 503, thereby facilitating adjustment of the position of the valve stem 5. The lever 503 has a directional function. The direction of the air inlet 502 and the exhaust hole 501 on the valve stem 5 can be determined by the direction of the lever 503, thereby facilitating rapid adjustment of the on and off of the air inlet nozzle 101 and the exhaust nozzle 6. The valve stem 5 is fixed in the valve hole 103 by the fixed shaft sleeve 504 to prevent the valve stem 5 from falling off from the valve hole 103.

[0039] Furthermore, the inner end surface of the air inlet nozzle 101 only has a fixedly connected first limiting ring 104, the lower end of the first limiting ring 104 is provided with a second spring 105 and a first ball 106, and the bottom of the inner end surface of the air inlet nozzle 101 is a conical structure.

[0040] The first ball 106 realizes unidirectional flow of air under the limiting action of the second spring 105. When the first piston rod 2 or the second piston rod 3 is pulled, the air flow can squeeze the first ball 106 from the outside through the air inlet nozzle 101 into the sampling sleeve 1. When exhausting, the first ball 106 blocks the air inlet nozzle 101 under the action of the second spring 105 and air pressure and cannot be discharged.

[0041] Furthermore, the outer end face of the exhaust nozzle 6 is provided with an external thread, the inner end face of the exhaust interface 102 is provided with an internal thread that cooperates with the exhaust nozzle 6, a second limiting ring 601 and a third limiting ring 602 are provided in the exhaust nozzle 6, and a third spring 605 and a second ball 603 are provided between the second limiting ring 601 and the third limiting ring 602.

[0042] Through the cooperation of the second limiting ring 601, the third limiting ring 602, the third spring 605 and the second ball 603, the air flow can only be discharged from the exhaust nozzle 6, and cannot enter the sampling sleeve 1 from the exhaust nozzle 6. The threaded connection method makes it convenient to inspect and replace the exhaust nozzle 6, and after it is removed, it is convenient to blow and clean the sampling sleeve 1 with a strong airflow.

[0043] Furthermore, the top of the sampling sleeve 1 is provided with an external thread, the inner end surface of the sealing cover 405 is provided with an internal thread that cooperates with the sampling sleeve 1, the center of the sealing cover 405 is provided with a sliding hole 406 that cooperates with the first piston rod 2, the side end surface of the sealing cover 405 is provided with an ear plate 407, and the limiting pressure rod 401 is provided with a torsion spring 403. The limiting pressure rod 401 is installed on the ear plate 407 and is elastically rotatably connected to it through the torsion spring 403.

[0044] The limiting pressure rod 401 is pressed on the top of the first piston rod 2 under the reset action of the torsion spring 403 to limit its sliding. When the limiting pressure rod 401 is pushed away, the first piston rod 2 can quickly bounce upward, thereby generating negative pressure in the sampling sleeve 1 for air extraction and sampling.

[0045] Furthermore, the limiting pressure rod 401 includes a connecting part 4011, a limiting part 4012 and a pressing part 4013. The limiting part 4012 is fixedly installed on the top of the connecting part 4011, and the pressing part 4013 is fixedly installed on the bottom of the connecting part 4011. A rotating shaft 4014 is provided at the bottom of the side end of the connecting part 4011, which is rotatably connected to the ear plate 407.

[0046] Under the action of the torsion spring 403, the limiting pressure rod 401 moves closer to the first piston rod 2, so that the limiting portion 4012 blocks the upper end surface of the first piston rod 2, thereby limiting the sliding of the first piston rod 2. By pressing the pressing portion 4013 with a finger, the limiting pressure rod 401 rotates around the rotating shaft 4014 under the action of the lever, releasing the limit on the first piston rod 2, so that it can pop out under the action of the first spring 7.

[0047] Furthermore, a limiting flange is provided on the top edge of the first piston rod 2, and rotatably connected rollers 4015 are provided on the left and right sides of the limiting portion 4012. The top lower end surface of the first piston rod 2 is provided with an annular recessed groove 202 that cooperates with the first spring 7.

[0048] The limiting flange increases the resistance of the limiting part 4012 when it slips, preventing it from falling off naturally. At the same time, by adding rollers 4015 on the left and right sides of the limiting part 4012, the wear between the limiting part 4012 and the first piston rod 2 is reduced, avoiding the wear of the limiting part 4012 or the annular flange 201 after repeated use, and at the same time improving the smoothness when moving the limiting pressure rod 401.

[0049] Furthermore, the first piston rod 2 includes a first piston head 205 and a first vertical rod 204, the top of the first vertical rod 204 is provided with a piston cavity 203 which passes through its bottom, the second piston rod 3 includes a second piston head 301, a second vertical rod 302 and a limit plate 304, the second piston head 301 is installed in the piston cavity 203 and is slidably connected to it, the second vertical rod 302 is fixedly installed on the top of the second piston head 301, and the limit part 4012 is fixedly installed on the top of the first vertical rod 204.

[0050] When the first piston rod 2 is pressed by the limiting pressure rod 401, the second piston rod 3 is repeatedly pulled and pulled, so that the external air circulates through the air inlet nozzle 101 into the piston chamber 203 and is then discharged through the exhaust nozzle 6, thereby discharging the air reserved in the air flow channel of the equipment and improving the sampling accuracy.

[0051] Furthermore, an exhaust plug 303 that is slidably matched with the air inlet nozzle 101 and a finger ring 305 on the top of the limiting plate 304 are provided at the bottom of the second piston head 301 .

[0052] By grasping the sampling sleeve 1 with one hand and inserting the thumb into the finger ring 305, the cyclic exhaust operation can be repeatedly performed in a small range. After the exhaust is completed, the pressing part 4013 of the limit pressure rod 401 is pressed to make the first piston rod 2 bounce upward under the action of the first spring 7 to perform the sampling operation. Only one hand is needed for the entire operation, and the other hand can be freed to fix the position of the filter hose on the air inlet nozzle 101 and adjust the sampling area.

[0053] When using this device, first observe the direction of the lever 503 on the valve stem 5 to ensure that the valve stem 5 is in a state where both the air inlet nozzle 101 and the exhaust nozzle 6 are connected to facilitate the circulation and exhaust operation. At the same time, ensure that the limiting pressure rod 401 is pressed on the top of the first piston rod 2, then connect the air inlet nozzle 101 to the filter, and connect the exhaust nozzle 6 to the detection equipment through a threaded connection. Then, grab the sampling sleeve 1 with your hand, and insert your thumb into the finger ring 305 on the top of the limiting plate 304 of the second piston rod 3. At this time, the first piston rod 2 is pressed by the limiting pressure rod 401, and the second piston rod 3 is repeatedly pulled and pulled to allow the external air flow to circulate through the air inlet nozzle 101 into the piston cavity 203 of the second piston rod 3, and then be discharged through the exhaust nozzle 6, thereby exhausting the air reserved in the air flow channel of the equipment and improving the sampling accuracy. After the exhaust is completed, the second piston rod 3 is pressed into the piston cavity 203, and then, press down the pressing part 4013 of the limiting pressure rod 401, and use the lever principle to rotate the limiting pressure rod 401 around the rotating shaft 4014 to release the limit on the first piston rod 2. The first piston rod 2 quickly bounces upward under the action of the first spring 7, so that negative pressure is generated in the sampling sleeve 1. At this time, the gas squeezes the first ball 106 in the air inlet nozzle 101 under the action of air pressure, passes through the air inlet nozzle 101 into the sampling sleeve 1 to complete the sampling, rotate the valve stem 5 to adjust to the blocking state of the air inlet nozzle 101 and the exhaust nozzle 6, and take it to the laboratory for testing. If the gas in the sampling sleeve 1 is to be discharged to the detection equipment, connect the air inlet pipe of the detection equipment with the exhaust nozzle 6, rotate the valve stem 5 to make the air inlet hole 502 horizontal and the exhaust hole 501 upward, and the air flow in the sampling sleeve 1 can be discharged from the exhaust nozzle 6.

[0054] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sampling device for detecting gas concentration in a mine, comprising a sampling sleeve (1) and a first piston rod (2), characterized in that: A first spring (7) is provided between the first piston rod (2) and the sampling sleeve (1), a limit assembly (4) is provided on the top of the sampling sleeve (1), and a second piston rod (3) is provided in a movable connection inside the first piston rod (2); The first piston rod (2) is movably mounted in the sampling sleeve (1); the limiting assembly (4) comprises a limiting pressure rod (401), a rotating shaft (4014), a torsion spring (403) and a sealing cover (405); the limiting assembly (4) is mounted on the top of the sampling sleeve (1) to limit the movement of the first piston rod (2); an air inlet nozzle (101) is provided at the bottom of the sampling sleeve (1); an exhaust nozzle (6) communicating with the air inlet nozzle (101) is provided at the bottom of the side end surface of the sampling sleeve (1); and a movably connected valve stem (5) is provided at the bottom of the side end surface of the sampling sleeve (1); The limiting pressure rod (401) comprises a connecting portion (4011), a limiting portion (4012) and a pressing portion (4013); the limiting portion (4012) is fixedly mounted on the top of the connecting portion (4011); the pressing portion (4013) is fixedly mounted on the bottom of the connecting portion (4011); and a rotating shaft (4014) rotatably connected to the ear plate (407) is provided at the bottom of the side end of the connecting portion (4011); A limiting flange is provided on the top edge of the first piston rod (2), and rotatably connected rollers (4015) are provided on the left and right sides of the limiting portion (4012). An annular recessed groove (202) is provided on the top lower end surface of the first piston rod (2) to cooperate with the first spring (7); The first piston rod (2) comprises a first piston head (205) and a first vertical rod (204); the top of the first vertical rod (204) is provided with a piston cavity (203) which is communicated with the bottom thereof; the second piston rod (3) comprises a second piston head (301), a second vertical rod (302) and a limit plate (304); the second piston head (301) is installed in the piston cavity (203) and is slidably connected thereto; the second vertical rod (302) is fixedly installed on the top of the second piston head (301); and the limit portion (4012) is fixedly installed on the top of the first vertical rod (204); The bottom of the second piston head (301) is provided with an exhaust plug (303) that is slidably matched with the air inlet nozzle (101), and a finger ring (305) is provided on the top of the limiting plate (304).

2. A sampling device for detecting gas concentration in a mine according to claim 1, characterized in that: A valve hole (103) is provided at the bottom of the side end surface of the sampling sleeve (1), a valve stem (5) for damping rotation of the sampling sleeve (1) is provided in the valve hole (103), an air inlet (502) is provided at the upper end of the valve stem (5) and is connected to the lower end surface, and an exhaust hole (501) is provided at the side end surface of the valve stem (5) and is connected to the air inlet (502).

3. A sampling device for detecting gas concentration in a mine as claimed in claim 2, characterized in that: A shift rod (503) is provided at the side end of the valve stem (5), and a fixed shaft sleeve (504) having an interference fit is provided at the end of the valve stem (5) away from the shift rod (503).

4. A sampling device for detecting gas concentration in a mine as claimed in claim 1, characterized in that: The inner end surface of the air inlet nozzle (101) has only a first limiting ring (104) fixedly connected thereto, a second spring (105) and a first ball (106) are provided at the lower end of the first limiting ring (104), and the bottom of the inner end surface of the air inlet nozzle (101) is a conical structure.

5. The sampling device for detecting gas concentration in a mine as claimed in claim 1, characterized in that: The outer end surface of the exhaust nozzle (6) is provided with an external thread, the bottom of the sampling sleeve (1) is provided with an exhaust interface (102), the inner end surface of the exhaust interface (102) is provided with an internal thread that cooperates with the exhaust nozzle (6), and a second limiting ring (601) and a third limiting ring (602) are provided in the exhaust nozzle (6), and a third spring (605) and a second ball (603) are provided between the second limiting ring (601) and the third limiting ring (602).

6. The sampling device for detecting gas concentration in a mine as claimed in claim 1, characterized in that: The top of the sampling sleeve (1) is provided with an external thread, the inner end surface of the sealing cover (405) is provided with an internal thread that cooperates with the sampling sleeve (1), the center of the sealing cover (405) is provided with a sliding hole (406) that cooperates with the first piston rod (2), the side end surface of the sealing cover (405) is provided with an ear plate (407), the limiting pressure rod (401) is provided with a torsion spring (403), and the limiting pressure rod (401) is installed on the ear plate (407) and is elastically rotatably connected to it through the torsion spring (403).

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