Sampling device for mine gas concentration detection

Abstract

A disclosed sampling device for mine gas concentration detection comprises a sampling sleeve and a first piston rod, a first spring is arranged between the first piston rod and the sampling sleeve, a limiting assembly is arranged at the top of the sampling sleeve, and a movably connected second piston rod is arranged in the first piston rod; the first piston rod is movably installed in the sampling sleeve, the limiting assembly comprises a limiting pressing rod, a rotating shaft, a torsion spring and a sealing cover, the limiting assembly is installed at the top of the sampling sleeve and used for limiting movement of the first piston rod, an air inlet nozzle is arranged at the bottom of the sampling sleeve, and an exhaust nozzle communicated with the air inlet nozzle is arranged at the bottom of the side end face of the sampling sleeve. A movably-connected valve rod is arranged at the bottom of the side end face of the sampling sleeve. The device has the advantages of being simple in structure, convenient to operate and capable of completing sampling and pre-exhausting operation with one hand, and the problems that an existing device is complex in valve, inconvenient to operate, prone to misoperation and capable of limiting field adjustment through double-hand operation are solved.

Description

Technical Field

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

[0002] In complex environments such as mines, the accurate detection of gas concentration is of great significance for ensuring operation safety, preventing gas explosion and toxic gas leakage accidents. And gas sampling, as a key link in the detection process, its accuracy directly affects the reliability of subsequent analysis results. The existing sampling devices for detecting the gas concentration in mines generally have the following problems:

[0003] Firstly, the valve structure of the existing devices is usually relatively complex, with cumbersome operations. Each time of inhalation and exhalation requires an adjustment operation, which is prone to misoperation, reducing work efficiency and safety. Secondly, the sampling device needs to be docked with a filtering hose to remove particulate impurities in the air. Most of the existing sampling devices require two hands to cooperate in operation. On the one hand, it increases the operation difficulty, and on the other hand, it limits the adjustment ability of the filtering hose by the operator during the sampling process, making it inconvenient to adjust the sampling position and affecting the overall operation efficiency. Summary of the Invention

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

[0005] To achieve the above purpose, the present invention provides the following technical solution: A sampling device for detecting the gas concentration in a mine, including a sampling sleeve and a first piston rod. A first spring is arranged between the first piston rod and the sampling sleeve. A limiting component is arranged at the top of the sampling sleeve. A second piston rod is movably connected inside the first piston rod;

[0006] The first piston rod is movably installed inside the sampling sleeve. The limiting component includes a limiting pressure rod, a rotating shaft, a torsion spring and a sealing cover. The limiting component is installed at the top of the sampling sleeve to limit the movement of the first piston rod. An air inlet nozzle is arranged at the bottom of the sampling sleeve. An exhaust nozzle communicating with the air inlet nozzle is arranged at the bottom of the side end face of the sampling sleeve. A valve rod is movably connected at the bottom of the side end face of the sampling sleeve.

[0007] As a preferred sampling device for detecting the gas concentration in a mine of the present invention, a valve hole is arranged at the bottom of the side end face of the sampling sleeve. A valve rod is rotationally connected to the sampling sleeve with damping in the valve hole. An air inlet hole is arranged at the upper end of the valve rod and is connected to the lower end face in a through manner. An exhaust hole communicating with the air inlet hole is arranged on the side end face of the valve rod.

[0008] Preferably, for a sampling device for mine gas concentration detection according to the present invention, a lever is provided at the side end of the valve stem, and an interference-fitted fixed bushing is provided at the end of the valve stem away from the lever.

[0009] Preferably, for a sampling device for mine gas concentration detection according to the present invention, only a first limit ring fixedly connected is provided on the inner end face of the air inlet nozzle. A second spring and a first ball are provided at the lower end of the first limit ring, and the bottom of the inner end face of the air inlet nozzle is of a conical structure.

[0010] Preferably, for a sampling device for mine gas concentration detection according to the present invention, an external thread is provided on the outer end face of the exhaust nozzle. An exhaust interface is provided at the bottom of the sampling sleeve. An internal thread matching the exhaust nozzle is provided on the inner end face of the exhaust interface. A second limit ring and a third limit ring are provided in the exhaust nozzle. A third spring and a second ball are provided between the second limit ring and the third limit ring.

[0011] Preferably, for a sampling device for mine gas concentration detection according to the present invention, an external thread is provided on the top of the sampling sleeve. An internal thread matching the sampling sleeve is provided on the inner end face of the sealing cover. A sliding hole matching the first piston rod is provided at the center of the sealing cover. An ear plate is provided on the side end face of the sealing cover. A torsion spring is provided on the limit pressing rod, and the limit pressing rod is installed on the ear plate and is elastically rotatably connected thereto through the torsion spring.

[0012] Preferably, for a sampling device for mine gas concentration detection according to the present invention, the limit pressing rod includes a connecting portion, a limiting portion, and a pressing portion. The limiting portion is fixedly installed at the top of the connecting portion. The pressing portion is fixedly installed at the bottom of the connecting portion. A rotating shaft rotatably connected to the ear plate is provided at the bottom of the side end of the connecting portion.

[0013] Preferably, for a sampling device for mine gas concentration detection according to the present invention, a limit flange is provided at the top edge of the first piston rod. Rollers rotatably connected are provided on the left and right sides of the limiting portion. An annular groove matching the first spring is provided on the lower end face of the top of the piston rod.

[0014] Preferably, for a sampling device for mine gas concentration detection according to the present invention, the second piston rod includes a first piston head and a first vertical rod. A piston cavity communicating with its bottom is provided at the top of the first vertical rod. The second piston includes a second piston head, a second vertical rod, and a limiting plate. The second piston head is installed in the piston cavity and is slidably connected thereto. The second vertical rod is fixedly installed at the top of the second piston head. The limiting portion is fixedly installed at the top of the vertical rod.

[0015] Preferably, as a sampling device for detecting the concentration of mine gas in the present invention, a drain plug in sliding fit with an air inlet nozzle is provided at the bottom of the second piston head, and a finger ring is provided at the top of the limiting plate.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. Through the T-shaped three-way hole formed by the air inlet hole and the exhaust hole inside the valve stem and its rotatable structure, and in combination with the pointing function of the external shift lever, the device realizes the rapid and intuitive switching of the gas channel mode. 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, achieving four working states: unidirectional air intake, unidirectional exhaust, complete sealing, or free flow. This effectively solves the problems of cumbersome valve operation, unclear switching, and easy errors in traditional sampling devices. Especially in the narrow and poorly lit mine environment, the pointing of the shift 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 bushing, avoiding accidental detachment during operation and ensuring the reliability of the equipment.

[0018] 2. Through the one-way valve structures respectively arranged at the air inlet nozzle and the exhaust nozzle, secondary protection is carried out to realize strict control of unidirectional gas flow. The one-way valve at the air inlet nozzle ensures that gas can only be inhaled and cannot flow back, and the one-way valve at the exhaust nozzle ensures that gas can only be discharged and cannot be inhaled. Combined with the completely sealed state of the valve stem, a double guarantee is formed. One is to prevent external dusty air or impurities from flowing back through the exhaust nozzle to contaminate the collected sample or the interior of the equipment during exhaust or idling; the other is to prevent gas leakage or contamination in the sampling sleeve due to accidental air pressure changes before and after sampling. Especially in the mine environment filled with dust, in addition, the exhaust nozzle adopts a threaded connection design, which is convenient for thorough purging and cleaning after disassembly, further ensuring the cleanliness and measurement accuracy during long-term use.

[0019] 3. Through the ingeniously integrated limiting component and the nested second piston rod structure, the device realizes efficient single-handed operation. The limiting pressure rod automatically locks the first piston rod under the action of the torsion spring. After unlocking, the first spring can instantly bounce up the first piston rod to complete the main sampling. In the locked state, the second piston rod can be repeatedly pulled and pushed with one hand. Its piston cavity and drain plug design enable external gas to enter the piston cavity through the one-way valve at the air inlet nozzle when the second piston rod is pulled and pushed, and then push the original gas in the piston cavity to be discharged through the one-way valve at the exhaust nozzle, forming a small cycle. This solves the key problem of non-sample gas pre-stored in the dead cavity inside the equipment contaminating the real sample. By pre-exhausting the gas, the representativeness and detection accuracy of the subsequent main sampling gas are significantly improved, and the whole process does not require the assistance of the other hand. Description of the Drawings

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

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

[0022] Figure 3 is the schematic diagram of the sectional structure of the first perspective of the present invention;

[0023] Figure 4 is the schematic diagram of the sectional structure of the second perspective of the present invention;

[0024] Figure 5 is the schematic diagram of the sampling sleeve structure of the present invention;

[0025] Figure 6 is of the present invention Figure 3 enlarged view at A in;

[0026] Figure 7 is of the present invention Figure 4 enlarged view at B in;

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

[0028] Figure 9 is the schematic diagram of the valve rod structure of the present invention;

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

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

[0031] In the figure: 1. Sampling sleeve; 101. Air inlet nozzle; 102. Exhaust interface; 103. Valve hole; 104. First limit ring; 105. Second spring; 106. First ball; 2. First piston rod; 201. Annular flange; 202. Annular dark groove; 203. Piston cavity; 204. First vertical rod; 205. First piston head; 3. Second piston rod; 301. Second piston head; 302. Second vertical rod; 303. Drain plug; 304. Limit plate; 305. Ring finger; 4. Limit assembly; 401. Limit pressure rod; 4011. Connection part; 4012. Limit part; 4013. Pressing part; 4014. Rotating shaft; 4015. Roller; 403. Torsion spring; 405. Sealing cover; 406. Slide hole; 407. Ear plate; 5. Valve rod; 501. Exhaust hole; 502. Air inlet hole; 503. Poking rod; 504. Fixed shaft sleeve; 6. Exhaust nozzle; 601. Second limit ring; 602. Third limit ring; 603. Second ball; 605. Third spring; 7. First spring. Detailed implementation manners

[0032] Embodiment 1

[0033] Please refer to Figures 1-11 , a sampling device for detecting the concentration of mine gas, including a sampling sleeve 1 and a first piston rod 2. A first spring 7 is arranged between the first piston rod 2 and the sampling sleeve 1. A limiting component 4 is arranged at the top of the sampling sleeve 1. A second piston rod 3 is movably connected inside the first piston rod 2;

[0034] The first piston rod 2 is movably installed inside the sampling sleeve 1. The limiting component 4 includes a limiting pressure rod 401, a rotating shaft 4014, a torsion spring 403 and a sealing cover 405. The limiting component 4 is installed at the top of the sampling sleeve 1 to limit the movement of the first piston rod 2. An air inlet nozzle 101 is arranged at the bottom of the sampling sleeve 1. An exhaust nozzle 6 communicating with the air inlet nozzle 101 is arranged at the bottom of the side end face of the sampling sleeve 1. A valve rod 5 is movably connected to the bottom of the side end face of the sampling sleeve 1.

[0035] Furthermore, a valve hole 103 is arranged at the bottom of the side end face of the sampling sleeve 1. The valve rod 5 is rotatably connected to the valve hole 103 of the sampling sleeve 1 in a damped manner. An air inlet hole 502 is arranged at the upper end of the valve rod 5 and is connected to the lower end face in a through manner. An exhaust hole 501 communicating with the air inlet hole 502 is arranged on the side end face of the valve rod 5.

[0036] Since a filter is usually externally connected to the air inlet nozzle 101 during sampling to filter particulate impurities, in order to avoid particulate impurities being blown into the detection device during exhaust, usually the gas flows unidirectionally from the air inlet nozzle 101 and out through the exhaust nozzle 6. The air inlet hole 502 and the exhaust hole 501 form a T-shaped three-way hole in the valve rod 5. By rotating the valve rod 5, the on-off of the air inlet nozzle 101 and the exhaust nozzle 6 is controlled. When the air inlet hole 502 is vertical and the exhaust hole 501 faces away from the exhaust nozzle 6, the air flow can only enter the sampling sleeve 1 through the air inlet nozzle 101. When the air inlet hole 502 is horizontal and the exhaust hole 501 faces upward, the air flow in the sampling sleeve 1 can only be discharged from the exhaust nozzle 6. When the air inlet hole 502 is horizontal and the exhaust hole 501 faces downward, both the air inlet nozzle 101 and the exhaust nozzle 6 are blocked, thereby avoiding gas leakage in the sampling sleeve 1. When the air inlet hole 502 is vertical and the exhaust hole 501 faces the exhaust nozzle 6, at this time both the air inlet nozzle 101 and the exhaust nozzle 6 are communicated with the inside of the sampling sleeve 1, and gas can freely enter and exit, 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 dial rod 503 is arranged at the side end of the valve rod 5. A fixed shaft sleeve 504 with an interference fit is arranged at the end of the valve rod 5 away from the dial rod 503.

[0038] The valve stem 5 can be easily moved by the lever 503, so that the position of the valve stem 5 can be adjusted. The lever 503 has a directional function. The direction of the air inlet hole 502 and the air exhaust hole 501 on the valve stem 5 can be determined by the direction of the lever 503, so as to quickly adjust the on and off of the air inlet nozzle 101 and the air 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 first limit ring 104 fixedly connected thereto, the lower end of the first limit 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 surface of the exhaust nozzle 6 is provided with an external thread, the inner end surface of the exhaust interface 102 is provided with an internal thread matching the exhaust nozzle 6, a second limiting ring 601 and a third limiting ring 602 are provided inside 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 airflow 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 facilitates the inspection and replacement of the exhaust nozzle 6, and after removal, it is easy to blow and clean the sampling sleeve 1 with a strong airflow.

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

[0045] Furthermore, the limiting pressure rod 401 includes a connecting portion 4011, a limiting portion 4012 and a pressing portion 4013. The limiting portion 4012 is fixedly installed on the top of the connecting portion 4011, and the pressing portion 4013 is fixedly installed on the bottom of the connecting portion 4011. 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.

[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, rotatably connected rollers 4015 are provided on the left and right sides of the limiting portion 4012, and an annular recessed groove 202 cooperating with the first spring 7 is provided on the top lower end surface of the piston rod.

[0048] The limiting flange increases the resistance of the limiting part 4012 when it slips off to prevent 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 second piston rod 3 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 is connected with the bottom thereof, the second piston 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 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 vertical rod.

[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 then is discharged through the exhaust nozzle 6, thereby exhausting the air reserved in the air flow channel of the equipment and improving the sampling accuracy.

[0051] Furthermore, an exhaust plug 303 that slidably matches 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 ring 305, the cyclic exhaust operation can be repeatedly performed in a small range. After the exhaust is completed, pressing the pressing part 4013 of the limit pressing rod 401 can cause the first piston rod 2 to bounce upward under the action of the first spring 7 to perform the sampling operation. The whole process only requires one hand to operate, 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 the device is in use, first observe the orientation of the lever 503 on the valve rod 5 to ensure that the valve rod 5 is in a state where both the air inlet nozzle 101 and the exhaust nozzle 6 are connected to facilitate the cyclic exhaust operation. At the same time, ensure that the limit pressing rod 401 presses on the top of the first piston rod 2. Then, connect the air inlet nozzle 101 to an external filter, connect the exhaust nozzle 6 to the detection device through threaded connection. Then, hold the sampling sleeve 1 with the hand and insert the thumb into the ring 305 at 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 limit pressing rod 401. Pull and push the second piston rod 3 repeatedly to make the external air flow circulate through the air inlet nozzle 101 into the piston chamber 203 of the second piston rod 3 and then be discharged through the exhaust nozzle 6, so as to discharge the air reserved in the air flow channel of the device and improve the sampling accuracy. After the exhaust is completed, press the second piston rod 3 to the bottom of the piston chamber 203. Then, press the pressing part 4013 of the limit pressing rod 401, and use the lever principle to make the limit pressing rod 401 rotate 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, generating negative pressure 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 and enters the sampling sleeve 1 through the air inlet nozzle 101 to complete the sampling. Rotate the valve rod 5 to adjust to the state where the air inlet nozzle 101 and the exhaust nozzle 6 are blocked, and carry it to the laboratory for detection. If it is necessary to discharge the gas in the sampling sleeve 1 to the detection device, connect the inlet pipe of the detection device to the exhaust nozzle 6, and rotate the valve rod 5 so that the air inlet hole 502 is horizontal and the exhaust hole 501 is upward, and the air flow in the sampling sleeve 1 can be discharged from the exhaust nozzle 6.

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

Claims

1. A sampling device for detecting the concentration of mine gas, comprising a sampling sleeve (1) and a first piston rod (2), characterized in that: A first spring (7) is arranged between the first piston rod (2) and the sampling sleeve (1). A limiting component (4) is arranged at the top of the sampling sleeve (1). A second piston rod (3) is movably connected inside the first piston rod (2). The first piston rod (2) is movably installed inside the sampling sleeve (1). The limiting component (4) includes a limiting pressure rod (401), a rotating shaft (4014), a torsion spring (403) and a sealing cover (405). The limiting component (4) is installed at the top of the sampling sleeve (1) to limit the movement of the first piston rod (2). An air inlet nozzle (101) is arranged at the bottom of the sampling sleeve (1). An exhaust nozzle (6) communicating with the air inlet nozzle (101) is arranged at the bottom of the side end face of the sampling sleeve (1). A valve rod (5) is movably connected to the bottom of the side end face of the sampling sleeve (1).

2. The sampling device for detecting the gas concentration in a mine according to claim 1, characterized in that: A valve hole (103) is arranged at the bottom of the side end face of the sampling sleeve (1). The valve rod (5) is rotationally connected to the valve hole (103) of the sampling sleeve (1) with damping. An air inlet hole (502) is arranged at the upper end of the valve rod (5) and is connected to communicate with the lower end face. An exhaust hole (501) communicating with the air inlet hole (502) is arranged on the side end face of the valve rod (5).

3. The sampling device for detecting the gas concentration in a mine according to claim 2, characterized in that: A lever (503) is arranged at the side end of the valve rod (5). A fixed shaft sleeve (504) with interference fit is arranged at the end of the valve rod (5) far away from the lever (503).

4. The sampling device for detecting the gas concentration in a mine according to claim 1, wherein: Only a first limiting ring (104) is fixedly connected to the inner end face of the air inlet nozzle (101). A second spring (105) and a first ball (106) are arranged at the lower end of the first limiting ring (104). The bottom of the inner end face of the air inlet nozzle (101) is of a conical structure.

5. The sampling device for detecting the gas concentration in a mine according to claim 1, wherein: External threads are arranged on the outer end face of the exhaust nozzle (6). An exhaust interface (102) is arranged at the bottom of the sampling sleeve (1). Internal threads matching with the exhaust nozzle (6) are arranged on the inner end face of the exhaust interface (102). A second limiting ring (601) and a third limiting ring (602) are arranged inside the exhaust nozzle (6). A third spring (605) and a second ball (603) are arranged between the second limiting ring (601) and the third limiting ring (602).

6. The sampling device for detecting the gas concentration in a mine according to claim 1, wherein: External threads are arranged at the top of the sampling sleeve (1). Internal threads matching with the sampling sleeve (1) are arranged on the inner end face of the sealing cover (405). A sliding hole (406) matching with the first piston rod (2) is arranged at the center of the sealing cover (405). An ear plate (407) is arranged on the side end face of the sealing cover (405). A torsion spring (403) is arranged on the limiting pressure rod (401). The limiting pressure rod (401) is installed on the ear plate (407) and is elastically rotationally connected thereto through the torsion spring (403).

7. The sampling device for detecting the gas concentration in a mine according to claim 1, characterized in that: 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 at the top of the connecting part (4011), the pressing part (4013) is fixedly installed at the bottom of the connecting part (4011), and a rotating shaft (4014) rotatably connected to the ear plate (407) is arranged at the bottom of the side end of the connecting part (4011).

8. The sampling device for detecting mine gas concentration according to claim 7, wherein: A limiting flange is arranged at the top edge of the first piston rod (2). Rotating rollers (4015) are arranged on the left and right sides of the limiting part (4012) in a rotatable connection manner. An annular recess (202) cooperating with the first spring (7) is arranged on the lower end surface of the top of the piston rod.

9. The sampling device for detecting the gas concentration in a mine according to claim 7, wherein: The second piston rod (3) includes a first piston head (205) and a first vertical rod (204). A piston cavity (203) communicating with the bottom is arranged at the top of the first vertical rod (204). The second piston includes a second piston head (301), a second vertical rod (302) and a limiting 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 at the top of the second piston head (301), and the limiting part (4012) is fixedly installed at the top of the vertical rod.

10. The sampling device for detecting the gas concentration in a mine according to claim 9, characterized in that: A drain plug (303) in sliding fit with the air inlet nozzle (101) is arranged at the bottom of the second piston head (301), and a finger ring (305) is arranged at the top of the limiting plate (304).

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