A device and method for rapidly determining gas content in a coal seam
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-11
- Publication Date
- 2026-05-29
Smart Images
Figure CN122108838A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of coal mine safety technology, specifically to an apparatus and method for rapidly determining the gas content of coal seams. Background Technology
[0002] my country is a major coal producer, but over 46% of its mines are high-gas or prone to gas outbursts. Gas (primarily methane, CH4), a clean energy source found in coal seams, causes gas outbursts, one of the most serious mine safety accidents during coal mining, resulting in devastating losses for the nation and its people. Therefore, understanding and mastering the gas situation in coal mines is crucial for ensuring safe mining operations. Gas exists within the pores of coal and is classified into free gas (existing in fracture spaces and obeying the gas law) and adsorbed gas (existing on the surface of micropores and inside coal particles, occupying vacancies and spaces in the coal molecule structure). Coal seam gas content refers to the amount of gas contained in one ton or unit volume of coal under natural conditions. It is a core parameter for coal mine gas disaster prevention, gas extraction, and comprehensive utilization. Accurate and rapid determination of coal seam gas content is of great significance for assessing the risk of coal and gas outbursts, developing reasonable extraction plans, and ensuring safe coal mine production.
[0003] Currently, the methods for determining the gas content of coal seams are mainly divided into direct methods and indirect methods. The most commonly used direct method is the borehole desorption method, which involves collecting coal cores through a coring tube, quickly loading the coal cores into a sealed container, measuring the amount of gas desorption under normal pressure, calculating the loss using empirical formulas, and finally summing them up to obtain the total gas content.
[0004] However, this method has significant drawbacks: the natural desorption process of coal samples under normal pressure is slow, typically taking several hours or even days to complete, which cannot meet the needs of rapid mine excavation and real-time disaster early warning. Therefore, there is an urgent need for a coal seam gas content determination technology and device that can minimize the measurement time and improve the measurement accuracy. Summary of the Invention
[0005] To achieve rapid and accurate determination of coal seam gas content, a device for rapid determination of coal seam gas content is provided, including a base, a sample chamber for holding coal samples on the base, a sealed door in the sample chamber, and a desorption acceleration structure for accelerating the desorption rate of gas in the coal sample inside the sample chamber. The desorption acceleration structure includes a coal sample crushing structure. The sample chamber is connected to a vacuum pump and a negative pressure bottle, and the sample chamber, negative pressure bottle, and vacuum pump are sequentially connected. A first valve is installed between the negative pressure bottle and the sample chamber, and a second valve is installed between the negative pressure bottle and the vacuum pump. A first pressure sensor for monitoring changes in air pressure inside the sample chamber is installed inside the sample chamber, and a second pressure sensor for monitoring changes in air pressure inside the negative pressure bottle is installed inside the negative pressure bottle. The base is connected to a control structure for controlling the first valve, the second valve, and the desorption acceleration structure.
[0006] Through the above technical solutions, an integrated device system is constructed, which combines sealed measurement, negative pressure extraction, accelerated analysis, precise monitoring, and automatic control. The accelerated analysis structure improves the gas desorption efficiency, and the negative pressure environment created by the vacuum pump and negative pressure bottle further promotes gas escape. The pressure sensor captures the pressure changes in the sample chamber and negative pressure bottle in real time, thereby quickly calculating the gas content. This solves the problems of slow desorption, complicated operation, and large errors in traditional measurement methods. At the same time, the device is designed with a fully sealed system to avoid measurement deviations caused by gas leakage, achieving rapid and accurate measurement of coal seam gas content, and meeting the needs of rapid tunneling and real-time disaster early warning in mines.
[0007] Optionally, the analytical acceleration structure includes an ultrasonic vibration system for applying ultrasonic vibrations to the coal sample and a heating structure, wherein the heating structure is disposed in the sample chamber and the negative pressure bottle.
[0008] The above technical solution employs a dual-effect synergistic approach of ultrasonic vibration and heating to accelerate desorption. Ultrasonic vibration generates high-frequency micro-vibrations in the pores of the coal sample, breaking the adsorption and binding force between gas molecules and the coal body, while simultaneously promoting the convection and escape of gas within the coal sample. The heating structure raises the temperature of the coal sample and the gas transport path, utilizing the temperature characteristics of gas adsorption to reduce the amount of gas adsorbed in the coal body and promote the rapid conversion of adsorbed gas into free gas. Both the sample chamber and the negative pressure bottle are equipped with heating structures to ensure stable gas temperature throughout the process, avoiding deviations in gas pressure monitoring due to temperature fluctuations. Compared to a single desorption method, the desorption efficiency is significantly improved.
[0009] Optionally, the coal sample crushing structure includes a moving blade group and a fixed blade group. The fixed blade group is fixedly connected to the inner wall of the circumferential surface of the sample chamber. The moving blade group includes a rotating blade and a central rotating shaft. The rotating blade is fixedly connected to one end of the central rotating shaft, and a drive motor is connected to the end of the central rotating shaft opposite to the rotating blade.
[0010] Through the above technical solution, the moving blade group and the fixed blade group form a shearing cooperation, and the drive motor drives the rotating blade to rotate, crushing large coal samples into fine particles, so that the gas trapped inside the coal sample is fully exposed and escapes quickly, solving the problems of insufficient gas desorption and slow speed of large coal samples; the crushing structure is integrated into the sample chamber, and the coal sample can be crushed directly after loading, without the need for additional equipment and coal sample transfer, reducing gas loss during the transfer process, while simplifying the operation process and improving the measurement efficiency.
[0011] Optionally, the sample chamber and the base are separate, and a connection structure is provided between the sample chamber and the base. The drive motor is fixedly connected to the base, and a rectangular rod is fixedly connected to the output shaft of the drive motor. A rectangular groove is opened at the end of the central rotating shaft away from the rotating blade. When the sample chamber and the base are connected, the rectangular rod is slidably connected in the rectangular groove.
[0012] If the sample chamber and base are designed as a single unit, gas from the coal sample may leak out during transportation to the measuring device after collection, leading to significant errors in the measurement structure. The aforementioned technical solution, with its separate design of the sample chamber and base, facilitates the separate delivery of the sample chamber underground for coal sample collection. The coal sample can be sealed immediately after collection, minimizing gas loss during surface transportation and ensuring the accuracy of the measurement data. The sliding fit between the rectangular rod and rectangular groove enables rapid power connection between the sample chamber and base. The rectangular structure stably transmits torque, ensuring the drive motor reliably rotates the moving blade assembly to complete the crushing process. Furthermore, it is easy to assemble and disassemble without complex tools, adapting to the operational needs of mine sites.
[0013] Optionally, the ultrasonic vibration system includes an ultrasonic generator, a transducer, and an amplitude transformer. The ultrasonic generator and the transducer are mounted on the base. A vibration base plate is provided on the lower inner surface of the sample chamber, and a through hole is provided on the lower surface of the sample chamber. When the sample chamber is connected to the base, the amplitude transformer is inserted into the through hole to drive the vibration base plate to vibrate.
[0014] Through the above technical solution, the ultrasonic generator produces a high-frequency electrical signal, which is converted into mechanical vibration by the transducer. The amplitude transformer amplifies the vibration and transmits it to the vibration base plate, causing the coal sample in the sample chamber to generate high-frequency micro-vibration. This ensures that the ultrasonic vibration acts evenly on all coal samples, avoiding insufficient desorption in some local coal samples. The cooperation between the amplitude transformer and the through hole enables precise transmission of vibration, and the split design does not affect the underground collection and sealing of the sample chamber. The structure is compact and the transmission is efficient, ensuring the resolution and acceleration effect of ultrasonic vibration.
[0015] Optionally, the connection structure includes insertion rods and insertion holes. Multiple insertion rods are arranged in a circumferential array on the lower surface of the sample chamber. Insertion holes are opened above the base. An annular connecting cavity is opened in the base, which connects the multiple insertion holes. A connecting ring is slidably connected in the connecting cavity, and a locking rod is connected to the connecting ring. Locking holes are opened on the surface of the insertion rods. When the sample chamber is connected to the base, the insertion rod is inserted into the insertion hole, and the locking rod is inserted into the locking hole.
[0016] With the above technical solution, when it is necessary to connect the sample chamber and the base, the insertion rod is inserted into the insertion hole, so that the end of the insertion rod enters the connecting cavity. Then, the operator rotates the connecting ring to insert the locking rod into the locking hole, thereby locking the insertion rod in the insertion hole, thus realizing the connection between the sample chamber and the base. Setting multiple insertion rods makes the connection between the bottom of the sample chamber and the base more stable, and rotating the connecting ring can allow multiple locking rods to be inserted into the locking hole at the same time, thus making it easier to fix the sample chamber and the base.
[0017] Optionally, the sample chamber is provided with a partition chamber. The lower end of the partition chamber has a partition hole communicating with the sample chamber, and the partition hole is semi-circular. The upper end of the partition chamber has a sealing hole communicating with the outside, and the sealing hole is also semi-circular. A central shaft is provided inside the partition chamber, and a sealing door is connected to the upper end of the central shaft. The sealing door has a semi-circular door panel to block the sealing hole. The lower end of the central shaft is connected to a partition door, which also has a semi-circular door panel to block the partition hole. When the sealing door is opened, the partition door blocks the partition hole, and the partition... A fixed baffle and a movable push plate are provided between the door and the partition plate. The fixed baffle is fixedly connected to the inner wall of the partition chamber's circumferential surface, and the movable push plate is fixedly connected to the partition door. The movable push plate is used to push the coal sample into the partition hole. When the sealing door is opened, both the movable push plate and the fixed baffle are located between the partition hole and the sealing hole. The central shaft includes an outer rod and an inner rod. The outer rod has a through hole connecting both ends, and the inner rod is slidably connected in the through hole. A locking block is fixedly connected to the lower end of the partition chamber, and a locking hole is opened at the upper end of the locking block. The shape of the locking hole is the same as that of the inner rod.
[0018] During the process of filling the sample chamber with coal, the door is open, which can cause gas from the coal sample to leak out of the filling chamber, leading to inaccurate measurement results. Furthermore, if multiple fillings are required, the door will open each time, causing gas leakage and affecting measurement accuracy. The above-mentioned technical solution addresses this by opening the sealed door and closing the partition door when coal samples are needed. The collected coal sample is placed into the partition chamber, and then the central shaft is rotated to close the sealed door while simultaneously opening the partition door. A moving push plate then pushes the coal sample from the partition chamber into the sample chamber. The central shaft is then rotated again to open the sealed door and close the partition door, separating the partition chamber from the sample chamber. At this point, the inner rod slides down into the locking hole under gravity, causing the locking block to restrict the rotation of the inner rod, thereby restricting the rotation of the central shaft and the partition door, and locking the partition door. By setting up the partition chamber as a transfer chamber, gas leakage during coal sample addition is reduced, resulting in more accurate gas volume detection and ensuring experimental accuracy.
[0019] The sample chamber and the negative pressure bottle are separate units. Therefore, if the connection between the sample chamber and the negative pressure bottle is not blocked, the gas in the sample chamber will flow out, causing the gas in the sample chamber to leak out. Optionally, the negative pressure bottle and the sample chamber are connected by a flexible hose, and the flexible hose is connected to the sample chamber by a thread. The sample chamber is equipped with a sealing structure, which includes a one-way door and a connecting pipe. The one-way door is hinged to the end of the connecting pipe located inside the sample chamber, and a torsion spring is provided at the hinge position of the one-way door and the connecting pipe. A hollow tube is provided at the end of the flexible hose. When the hollow tube is inserted into the gas outlet, the hollow tube will open the one-way door.
[0020] Through the above technical solution, the threaded connection ensures the airtightness of the connection between the hose and the sample chamber, preventing gas leakage during transmission. The one-way door and torsion spring form a one-way automatic sealing structure. Under normal conditions, the torsion spring drives the one-way door to close the connecting tube, preventing gas leakage from the sample chamber. When the hollow tube is inserted, it opens the one-way door, enabling communication between the sample chamber and the negative pressure bottle, allowing gas to enter the negative pressure bottle smoothly. After the tube is pulled out, the torsion spring drives the one-way door to automatically reset and seal, requiring no additional operation. This structure achieves a quick and sealed connection between the hose and the sample chamber, is convenient to operate, and has high sealing reliability, effectively avoiding measurement errors caused by gas leakage.
[0021] This application also discloses a method for rapidly determining the gas content in coal seams using an apparatus, characterized by comprising the following steps:
[0022] S1. Fill the sample chamber with the coal sample taken from the mine and seal it immediately;
[0023] S2. Close the first valve, use a vacuum pump to extract the gas from the negative pressure bottle, record the initial pressure reading of the second pressure sensor, zero it, and then close the second valve.
[0024] S3. Start the parsing acceleration structure and shut it down after working continuously for at least 10 minutes.
[0025] S4. Record the reading p1 of the first pressure sensor in the sample chamber;
[0026] S5. Open the first valve. After the readings of the first and second pressure sensors are consistent and stabilize for several seconds, record the reading p2 of the second pressure sensor at this time.
[0027] S6. Based on the sample chamber volume V c Negative pressure bottle volume V b And p1, p2, calculate the volume of the coal sample;
[0028] S7. Restart the analysis acceleration structure until the desorption rate is lower than the set threshold, and calculate the volume of desorbed gas in real time.
[0029] The above technical solution greatly simplifies the operation steps for determining the gas content of coal seams. At the same time, the use of analytical acceleration structure speeds up the determination of coal seam gas content, enabling rapid and accurate determination of coal seam gas content, which is suitable for the needs of rapid tunneling and real-time disaster early warning in mines.
[0030] Optionally, the gas volume and coal sample volume in S7 are calculated using the following formula: coal sample volume;
[0031] Gas volume; ,
[0032] p represents the real-time reading from either the first or second barometric pressure sensor.
[0033] One or more technical solutions provided by this invention have at least the following technical effects or advantages:
[0034] 1. By setting up an analytical acceleration structure, the gas release in the coal sample is accelerated, and the gas content in the sample chamber and the negative pressure bottle is calculated by detecting the gas pressure in the first and second pressure sensors, thereby achieving rapid and accurate detection of coal seam gas content.
[0035] 2. This application takes into account the air inside the device in its calculations, unlike the traditional non-drainage method for measuring gas volume, which often ignores or roughly estimates the volume of free space remaining after the coal sample is loaded into the sample chamber. This makes the gas volume calculation in this application more accurate.
[0036] 3. By setting up a partitioned compartment, the volume of gas outflow is reduced when adding coal samples, thereby making the detected gas content more accurate. Attached Figure Description
[0037] The accompanying drawings, which are provided to further illustrate embodiments of the invention and constitute a part of this invention, are not intended to limit the scope of the invention.
[0038] Figure 1 This is a schematic diagram of the overall structure of this application;
[0039] Figure 2 This is a cross-sectional view of the overall structure of this application;
[0040] Figure 3 This application is intended to emphasize the partial structural cross-section of the coal sample's pulverized structure;
[0041] Figure 4 This application is intended to emphasize a partial structural cross-sectional view of the drive motor;
[0042] Figure 5 This is a partial structural cross-sectional view intended to emphasize the internal structure of the base in this application;
[0043] Figure 6 This is a partial structural diagram intended to emphasize the central pivot point in this application;
[0044] Figure 7 This is a partial structural diagram intended to emphasize the open state of the sealed door in this application;
[0045] Figure 8 This is a partial structural diagram intended to emphasize the partially closed state of the sealed door in this application;
[0046] Figure 9 This application is intended to emphasize the partial structural cross-section of the partition door in a half-open state;
[0047] Figure 10 This application is intended to emphasize a partial structural cross-sectional view at the central axis;
[0048] Figure 11 This application is intended to emphasize a partial structural cross-sectional view of the one-way door.
[0049] The components include: 1. Base; 2. Sample chamber; 21. First pressure sensor; 3. Coal sample crushing structure; 31. Rotating blade; 32. Central rotating shaft; 321. Rectangular groove; 33. Drive motor; 331. Rectangular rod; 34. Fixed blade assembly; 4. Vacuum pump; 5. Negative pressure bottle; 51. First valve; 52. Second valve; 53. Second pressure sensor; 6. Ultrasonic vibration system; 61. Vibrating base plate; 62. Amplitude bar; 7. Heating structure; 8. Connecting structure; 81. Insert rod; 82. Insertion hole; 83. Connecting cavity; 84. Connecting ring; 85. Locking rod; 86. Locking hole; 9. Separating chamber; 91. Separating door; 92. Sealing door; 93. Fixed baffle; 94. Moving push plate; 95. Central shaft; 951. Outer rod; 952. Inner rod; 96. Locking block; 961. Locking hole; 10. One-way door; 101. Connecting pipe. Detailed Implementation
[0050] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other.
[0051] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.
[0052] Reference Figure 1 and Figure 2A device for rapidly determining the gas content of coal seams includes a base 1, a sample chamber 2 for holding coal samples mounted on the base 1, a sealed door in the sample chamber 2, and an analysis acceleration structure for accelerating the gas analysis rate within the coal sample, the analysis acceleration structure including a coal sample crushing structure 3. The sample chamber 2 is connected to a vacuum pump 4 and a negative pressure bottle 5, the sample chamber 2, the negative pressure bottle 5, and the vacuum pump 4 are sequentially connected, and a first valve 51 is installed between the negative pressure bottle 5 and the sample chamber 2, and a second valve 52 is installed between the negative pressure bottle 5 and the vacuum pump 4. A first pressure sensor 21 for monitoring changes in air pressure within the sample chamber 2 is installed inside the sample chamber 2, and a second pressure sensor 53 for monitoring changes in air pressure within the negative pressure bottle 5 is installed inside the negative pressure bottle 5. The base 1 is connected to a control structure for controlling the first valve 51, the second valve 52, and the analysis acceleration structure. An integrated device system combining sealed measurement, negative pressure extraction, accelerated analysis, precise monitoring, and automatic control is constructed. The accelerated analysis structure improves the gas desorption efficiency, and the negative pressure environment created by the vacuum pump 4 and the negative pressure bottle 5 further promotes gas escape. The pressure sensor captures the pressure changes in the sample chamber 2 and the negative pressure bottle 5 in real time, thereby quickly calculating the gas content. This solves the problems of slow desorption, complicated operation, and large errors in traditional measurement methods. At the same time, the device is designed with a fully sealed system to avoid measurement deviations caused by gas leakage, achieving rapid and accurate measurement of coal seam gas content, and is suitable for the needs of rapid tunneling and real-time disaster early warning in mines.
[0053] Reference Figure 2 The desorption acceleration structure includes an ultrasonic vibration system 6 for applying ultrasonic vibrations to the coal sample and a heating structure 7, which is located inside the sample chamber 2 and the negative pressure bottle 5. This desorption acceleration method employs a dual-effect synergy of ultrasonic vibration and heating. The ultrasonic vibration generates high-frequency micro-vibrations in the pores of the coal sample, breaking the adsorption binding force between gas molecules and the coal body, while simultaneously promoting the convection and escape of gas within the coal sample. The heating structure 7 raises the temperature of the coal sample and the gas transport path, utilizing the temperature characteristics of gas adsorption to reduce the amount of gas adsorbed in the coal body and promote the rapid conversion of adsorbed gas into free gas. Both the sample chamber 2 and the negative pressure bottle 5 are equipped with the heating structure 7 to ensure stable gas temperature throughout the process, avoiding pressure monitoring deviations caused by temperature fluctuations. Compared to a single desorption method, the desorption efficiency is significantly improved.
[0054] By simultaneously incorporating mechanical crushing, heat-induced desorption (controlled heating at 50℃), and ultrasonic vibration (cavitation, thermal effect, and mechanical vibration) within a sealed sample chamber, the desorption rate is significantly enhanced. Furthermore, by measuring the pressure balance between sample chamber 2 and negative pressure bottle 5, the actual volume of the coal sample is calculated, eliminating the influence of sample loading errors on the measurement results.
[0055] Reference Figure 3 and Figure 4The coal sample crushing structure 3 includes a moving blade assembly and a fixed blade assembly 34. The fixed blade assembly 34 is fixedly connected to the inner wall of the circumferential surface of the sample chamber 2. The moving blade assembly includes a rotating blade 31 and a central rotating shaft 32. The rotating blade 31 is fixedly connected to one end of the central rotating shaft 32, and a drive motor 33 is connected to the end of the central rotating shaft 32 opposite to the rotating blade 31. The moving blade assembly and the fixed blade assembly 34 form a shearing engagement. The drive motor 33 drives the rotating blade 31 to rotate, crushing large coal samples into fine particles, allowing the gas trapped inside the coal sample to be fully exposed and escape quickly, solving the problems of insufficient gas desorption and slow speed in large coal samples. The crushing structure is integrated inside the sample chamber 2, and the coal sample can be crushed directly after loading, without the need for additional equipment or coal sample transfer, reducing gas loss during the transfer process, simplifying the operation process, and improving the measurement efficiency.
[0056] Reference Figure 4 and Figure 5 The sample chamber 2 and the base 1 are separate units, connected by a connecting structure 8. A drive motor 33 is fixedly connected to the base 1, and a rectangular rod 331 is fixedly connected to the output shaft of the drive motor 33. A rectangular groove 321 is formed at the end of the central rotating shaft 32 opposite to the rotating blade 31. When the sample chamber 2 is connected to the base 1, the rectangular rod 331 slides within the rectangular groove 321. This separate design of the sample chamber 2 and the base 1 facilitates the separate delivery of the sample chamber 2 underground to collect coal samples. The coal samples can be sealed immediately after collection, minimizing gas loss during surface transportation and ensuring the accuracy of the measured data. The sliding fit between the rectangular rod 331 and the rectangular groove 321 enables rapid power connection between the sample chamber 2 and the base 1. The rectangular structure stably transmits torque, ensuring that the drive motor 33 can reliably drive the rotating blade assembly to complete the crushing process. Furthermore, it is easy to assemble and disassemble without complex tools, adapting to the operational needs of the mine site.
[0057] Reference Figure 4 The ultrasonic vibration system 6 includes an ultrasonic generator, a transducer, and an amplitude transformer 62. The ultrasonic generator and transducer are mounted on the base 1. A vibration base plate 61 is provided on the lower inner surface of the sample chamber 2, and a through hole is opened on the lower surface of the sample chamber 2. When the sample chamber 2 is connected to the base 1, the amplitude transformer 62 is inserted into the through hole to drive the vibration base plate 61 to vibrate. The ultrasonic generator generates a high-frequency electrical signal, which is converted into mechanical vibration by the transducer. The amplitude transformer 62 amplifies the vibration and transmits it to the vibration base plate 61, causing the coal sample in the sample chamber 2 to generate high-frequency micro-vibration as a whole. This ensures that the ultrasonic vibration acts evenly on all coal samples, avoiding insufficient desorption of local coal samples. The cooperation between the amplitude transformer 62 and the through hole enables precise transmission of vibration, and the split design does not affect the underground sampling and sealing of the sample chamber 2. The structure is compact and the transmission is efficient, ensuring the resolution acceleration effect of ultrasonic vibration.
[0058] Reference Figure 4 and Figure 5The connecting structure 8 includes insertion rods 81 and insertion holes 82. Multiple insertion rods 81 are arranged in a circumferential array on the lower surface of the sample chamber 2. The insertion holes 82 are opened above the base 1. An annular connecting cavity 83 is opened in the base 1, which connects the multiple insertion holes 82. A connecting ring 84 is slidably connected in the connecting cavity 83. A sliding hole is opened on the side surface of the base, and a sliding rod is slidably connected in the sliding hole. The sliding rod is connected to the connecting ring. A locking rod 85 is connected to the connecting ring 84. A locking hole 86 is opened on the surface of the insertion rod 81. When the sample chamber 2 is connected to the base 1, the insertion rod 81 is inserted into the insertion hole 82, and the locking rod 85 is inserted into the locking hole 86. When it is necessary to connect the sample chamber 2 and the base 1, insert the insertion rod 81 into the insertion hole 82, so that the end of the insertion rod 81 enters the connecting cavity 83. Then, the operator slides the slide rod to drive the connecting ring 84 to rotate, so that the locking rod 85 is inserted into the locking hole 86, thereby locking the insertion rod 81 in the insertion hole 82, thus connecting the sample chamber 2 and the base 1. Setting multiple insertion rods 81 makes the connection between the bottom of the sample chamber 2 and the base 1 more stable, and rotating the connecting ring 84 can allow multiple locking rods 85 to be inserted into the locking hole 86 at the same time, thus making it easier to fix the sample chamber 2 and the base 1.
[0059] Reference Figures 6-10 The sample chamber 2 is equipped with a partition chamber 9. The lower end of the partition chamber 9 has a partition hole communicating with the sample chamber 2, and the partition hole is semi-circular. The upper end of the partition chamber 9 has a sealing hole communicating with the outside, and the sealing hole is also semi-circular. A central shaft 95 is installed inside the partition chamber 9. The upper end of the central shaft 95 is connected to a sealing door 92, which has a semi-circular door panel to block the sealing hole. The lower end of the central shaft 95 is connected to a partition door 91, which also has a semi-circular door panel to block the partition hole. When the sealing door 92 is opened, the partition door 91 blocks the partition hole, and a fixing baffle is installed between the partition door 91 and the partition plate. Plate 93 and movable push plate 94, fixed baffle 93 are fixedly connected to the inner wall of the circumferential surface of the partition chamber 9, movable push plate 94 is fixedly connected to partition door 91, movable push plate 94 is used to push coal sample into partition hole, when sealing door 92 is opened, movable push plate 94 and fixed baffle 93 are both located between partition hole and sealing hole, central shaft 95 includes outer rod 951 and inner rod 952, outer rod 951 has through hole connecting the two ends, inner rod 952 is slidably connected in through hole, lower end of partition chamber 9 is fixedly connected to locking block 96, upper end of locking block 96 has locking hole 961, the shape of locking hole 961 is the same as the shape of inner rod 952.
[0060] When coal samples need to be collected, the sealing door 92 is opened, and the partition door 91 is closed. The collected coal sample is placed into the partition chamber 9. Then, the central shaft 95 is rotated to close the sealing door 92 and open the partition door 91. The push plate 94 is moved to push the coal sample in the partition chamber 9 into the sample chamber 2. Then, the central shaft 95 is rotated again to open the sealing door 92 and close the partition door 91, separating the partition chamber 9 from the sample chamber 2. At this time, the inner rod slides down into the locking hole 961 under the influence of gravity, so that the locking block 96 restricts the rotation of the inner rod 952, thereby restricting the rotation of the central shaft 95 and the partition door 91, and locking the partition door 91. By setting the partition chamber 9 as a transfer chamber, the gas outflow when adding coal samples is reduced, so that the detected gas volume is more accurate and the accuracy of the experiment is ensured.
[0061] Reference Figure 11 The negative pressure bottle 5 is connected to the sample chamber 2 by a hose, and the hose is connected to the sample chamber 2 by a thread. The sample chamber 2 is equipped with a sealing structure, which includes a one-way door 10 and a connecting pipe 101. The one-way door 10 is hinged to one end of the connecting pipe 101 located inside the sample chamber 2, and a torsion spring is provided at the hinge position between the one-way door 10 and the connecting pipe 101. A hollow tube is provided at the end of the hose. When the hollow tube is inserted into the gas outlet, the hollow tube pushes open the one-way door 10. The threaded connection ensures a tight seal between the hose and the sample chamber 2, preventing gas leakage during transmission. The one-way door 10 and the torsion spring form a one-way automatic sealing structure. Under normal conditions, the torsion spring drives the one-way door 10 to close the connecting pipe 101, preventing gas leakage from the sample chamber 2. When the hollow tube is inserted, it opens the one-way door 10, connecting the sample chamber 2 with the negative pressure bottle 5, allowing gas to enter the negative pressure bottle 5 smoothly. After the tube is pulled out, the torsion spring drives the one-way door 10 to automatically reset and seal, requiring no additional operation. This structure enables a quick and sealed connection between the hose and the sample chamber 2, is convenient to operate, and has high sealing reliability, effectively avoiding measurement errors caused by gas leakage.
[0062] This application also discloses a method for rapidly determining the gas content in coal seams using an apparatus, comprising the following steps:
[0063] S1. Fill the sample chamber 2 with the coal sample taken from the mine and seal it immediately;
[0064] S2. Close the first valve 51, use the vacuum pump 4 to extract the gas from the negative pressure bottle 5, record the initial pressure reading of the second pressure sensor 53, zero it, and then close the second valve 52.
[0065] S3. Start the parsing acceleration structure and shut it down after working continuously for at least 10 minutes.
[0066] S4. Record the reading p1 of the first pressure sensor 21 inside the sample chamber 2;
[0067] S5. Open the first valve 51. After the readings of the first pressure sensor 21 and the second pressure sensor 53 are consistent and stable for several seconds, record the reading p2 of the second pressure sensor 53 at this time.
[0068] S6. Calculate the volume of the coal sample based on the volume Vc of sample chamber 2, the volume Vb of negative pressure bottle 5, and p1 and p2.
[0069] S7. Restart the analysis acceleration structure until the desorption rate is lower than the set threshold, and calculate the volume of desorbed gas in real time.
[0070] The volume of the coal sample in S6 is calculated using the following formula: Coal sample volume ;
[0071] The gas volume in S7 is calculated using the following formula: Gas Volume ;
[0072] p represents the real-time reading from either the first or second barometric pressure sensor.
[0073] The formulas for calculating gas volume and coal sample volume in S7 are derived through the following steps:
[0074] Given the sample chamber volume Vc, the negative pressure bottle volume Vb, and the front and rear gas pressures p1 and p2. In step 4, the gas volume inside the sample chamber is the free volume of the sample chamber (i.e., (Vs is the volume of the coal sample), and the gas pressure is p1. After opening the valve in step 5, the gas diffuses into the entire free space of the sample chamber and the negative pressure bottle, with a total volume of: After equilibrium is reached, the gas pressure is p2. Since the temperature is constant and the total amount of gas remains constant, according to the ideal gas law, we can obtain:
[0075]
[0076] The final coal sample volume is obtained by solving:
[0077]
[0078] Furthermore, the air volume inside the device can be obtained: Therefore, the amount of air, n_air, can be obtained: (By default, the device is in standard condition for a very short period of time after the coal sample is loaded).
[0079] Furthermore, regarding the principle of gas volume measurement: the theoretical basis of this method is the ideal gas law. The ideal gas law is stated as: Where: P is the gas pressure, V is the gas volume, n is the amount of substance of the gas, R is the ideal gas constant (taken as 8.314), and T is the thermodynamic temperature. Therefore, after the device has completed its operation, the amount of gas desorbed, ngas (assuming the gas pressure at complete desorption is p3), is:
[0080]
[0081] Furthermore, based on the calculated amount of substance n of the gas, the volume Vgas of the released gas under standard conditions can be obtained as follows:
[0082]
[0083] Furthermore, at any time after step 7, let the gas pressure of the device at that time be p. Then, the corresponding volume V of desorbed gas at that time is: During this period, the pressure change can be converted into volume change in real time according to the formula, saving manual calculation.
[0084] Finally, the gas content of the coal seam can be obtained as follows:
[0085]
[0086] In the above formula: p1—the air pressure in the sample chamber after the device has been working for 10 minutes.
[0087] p2 – The pressure in the sample chamber and negative pressure bottle after a few seconds of equilibrium.
[0088] p3 — Equilibrium pressure in the device after complete desorption
[0089] Vb — Sample chamber volume
[0090] Furthermore, the coal sample in S1 should fill at least 80% of the sample chamber 2. This reduces the free space within the sample chamber 2, allowing the desorbed gas to be drawn into the negative pressure bottle 5 more quickly. Secondly, it improves the sensitivity to pressure changes, making it easier for the sensor to capture minute pressure variations and enhancing measurement accuracy. If the sample chamber 2 is underfilled, the free space will be large, causing gas to diffuse slowly, delaying the desorption and extraction process, and the pressure changes will be less noticeable, leading to increased calculation errors. Simultaneously, the coal sample may not fully contact the crushing blade assembly and the ultrasonic working head, reducing desorption efficiency.
[0091] Furthermore, the method used in this application has advantages over the drainage method: the principle of the drainage method is that the desorbed gas will increase the gas pressure inside the device, causing water to be discharged, and the volume of desorbed gas is measured by the change in liquid level. This method has many limitations: firstly, the drainage method requires a series of glass containers such as water tanks, water storage bottles, and measuring cylinders, making the device bulky and complex to connect, which is extremely unfriendly to the narrow, humid, and vibrating working environment underground, and there is also a risk of water leakage and instrument breakage. The device used in this application has a compact structure, is robust and pressure-resistant, and is more suitable for rapid underground mobile operations.
[0092] Secondly, the drainage method indirectly measures gas volume through water level changes, which is susceptible to interference from various factors such as ambient atmospheric pressure fluctuations, water temperature changes, water vapor partial pressure, and gas solubility in water. This results in numerous sources of system error that are difficult to completely correct. The operation requires multiple manual visual readings, introducing subjective errors and time blind spots in intermittent measurements. Furthermore, this patent directly uses high-precision pressure and temperature sensors to collect system pressure and temperature data in real time and continuously, and automatically calculates based on the ideal gas law. The entire process is fully automated, avoiding most human intervention and environmental interference, achieving higher measurement accuracy and real-time performance. Finally, the drainage method is prone to gas leakage when the gas desorption rate is too high or too fast, leading to measurement failure and even safety hazards. Therefore, it is not suitable for rapid determination of coal samples with high gas content. This patent uses a fully enclosed pipeline and an active vacuum pumping system, with an adjustable pumping rate, enabling safe and effective handling of large-flow gas desorption. It is highly adaptable and safe.
[0093] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0094] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A device for rapidly determining the gas content of coal seams, characterized in that, The system includes a base (1), a sample chamber (2) for holding coal samples is provided on the base (1), an analysis acceleration structure for accelerating the gas analysis rate in the coal sample is provided in the sample chamber (2), the analysis acceleration structure includes a coal sample crushing structure (3), a vacuum pump (4) and a negative pressure bottle (5) are connected to the sample chamber (2), the sample chamber (2), the negative pressure bottle (5) and the vacuum pump (4) are connected in sequence, and a first valve (51) is provided between the negative pressure bottle (5) and the sample chamber (2), and a second valve (52) is provided between the negative pressure bottle (5) and the vacuum pump (4). A first pressure sensor (21) for monitoring the gas pressure change in the sample chamber (2) is provided in the sample chamber (2), and a second pressure sensor (53) for monitoring the gas pressure change in the negative pressure bottle (5) is provided in the negative pressure bottle (5), and a control structure for controlling the first valve (51), the second valve (52) and the analysis acceleration structure is connected to the base (1).
2. The device for rapidly determining the gas content of coal seams according to claim 1, characterized in that, The analytical acceleration structure includes an ultrasonic vibration system (6) for applying ultrasonic vibrations to the coal sample and a heating structure (7), which is located in the sample chamber (2) and the negative pressure bottle (5).
3. The device for rapidly determining the gas content of coal seams according to claim 2, characterized in that, The coal sample crushing structure (3) includes a moving blade group and a fixed blade group (34). The fixed blade group (34) is fixedly connected to the inner wall of the circumferential surface of the sample chamber (2). The moving blade group includes a rotating blade (31) and a central rotating shaft (32). The rotating blade (31) is fixedly connected to one end of the central rotating shaft (32). The end of the central rotating shaft (32) opposite to the rotating blade (31) is connected to a drive structure.
4. The device for rapidly determining the gas content of coal seams according to claim 3, characterized in that, The sample chamber (2) and the base (1) are set separately. A connecting structure (8) is provided between the sample chamber (2) and the base (1). The driving structure is fixedly connected to the base (1). The output shaft of the driving structure is fixedly connected to a rectangular rod (331). A rectangular groove (321) is opened at the end of the central rotating shaft (32) away from the rotating blade (31). When the sample chamber (2) is connected to the base (1), the rectangular rod (331) is slidably connected in the rectangular groove (321).
5. The device for rapidly determining the gas content of coal seams according to claim 4, characterized in that, The ultrasonic vibration system (6) includes an ultrasonic generator, a transducer, and an amplitude transformer (62). The ultrasonic generator and the transducer are mounted on the base (1). A vibration base plate (61) is provided on the lower inner surface of the sample chamber (2), and a through hole is provided on the lower surface of the sample chamber (2). When the sample chamber (2) is connected to the base (1), the amplitude transformer (62) is inserted into the through hole to drive the vibration base plate (61) to vibrate.
6. The device for rapidly determining the gas content of coal seams according to claim 5, characterized in that, The connection structure (8) includes a plug (81) and a socket (82). Multiple plugs (81) are arranged in a circular array on the lower surface of the sample chamber (2). The socket (82) is opened above the base (1). An annular connecting cavity (83) is opened in the base (1). The connecting cavity (83) connects the multiple sockets (82). A connecting ring (84) is slidably connected in the connecting cavity (83). A locking rod (85) is connected to the connecting ring (84). A locking hole (86) is opened on the surface of the plug (81). When the sample chamber (2) is connected to the base (1), the plug (81) is inserted into the socket (82) and the locking rod (85) is inserted into the locking hole (86).
7. The device for rapidly determining the gas content of coal seams according to claim 6, characterized in that, The sample chamber (2) is provided with a partition chamber (9). The lower end of the partition chamber (9) is provided with a partition hole communicating with the sample chamber (2), and the partition hole is a semi-circular hole. The upper end of the partition chamber (9) is provided with a sealing hole communicating with the outside, and the sealing hole is a semi-circular hole. A central shaft (95) is provided inside the partition chamber (9). The upper end of the central shaft (95) is connected to a sealing door (92). The sealing door (92) is a semi-circular door plate used to block the sealing hole. The lower end of the central shaft (95) is connected to a partition door (91). The partition door (91) is a semi-circular door plate used to block the partition hole. When the sealing door (92) is opened, the partition door (91) blocks the partition hole. A fixed baffle (93) is provided between the partition door (91) and the partition plate. The movable push plate (94) and the fixed baffle (93) are fixedly connected to the inner wall of the circumferential surface of the partition chamber (9). The movable push plate (94) is fixedly connected to the partition door (91). The movable push plate (94) is used to push the coal sample into the partition hole. When the sealing door (92) is opened, the movable push plate (94) and the fixed baffle (93) are both located between the partition hole and the sealing hole. The central shaft (95) includes an outer rod (951) and an inner rod (952). The outer rod (951) has a through hole connecting both ends. The inner rod (952) is slidably connected in the through hole. The lower end of the partition chamber (9) is fixedly connected to a locking block (96). The upper end of the locking block (96) has a lock hole (961). The shape of the lock hole (961) is the same as the shape of the inner rod (952).
8. The device for rapidly determining the gas content of coal seams according to claim 6, characterized in that: The negative pressure bottle (5) is connected to the sample chamber (2) by a hose. The hose is connected to the sample chamber (2) by a thread. The sample chamber (2) is equipped with a sealing structure, which includes a one-way door (10) and a connecting pipe (101). The one-way door (10) is hinged to the connecting pipe (101) at one end inside the sample chamber (2). A torsion spring is provided at the hinge position between the one-way door (10) and the connecting pipe (101). A hollow tube is provided at the end of the hose. When the hollow tube is inserted into the gas outlet, the hollow tube pushes open the one-way door (10).
9. The method for determining the gas content in a coal seam using a device according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Fill the sample chamber (2) with the coal sample taken from the mine and seal it immediately; S2. Close the first valve (51), use the vacuum pump (4) to extract the gas in the negative pressure bottle (5), record the initial pressure reading of the second pressure sensor (53), zero it, and then close the second valve (52). S3. Start the parsing acceleration structure and shut it down after working continuously for at least 10 minutes. S4. Record the reading p1 of the first pressure sensor (21) in the sample chamber (2); S5. Open the first valve (51). After the readings of the first pressure sensor (21) and the second pressure sensor (53) are consistent and stable for several seconds, record the reading p2 of the second pressure sensor (53) at this time. S6. Calculate the volume of the coal sample based on the volume Vc of the sample chamber (2), the volume Vb of the negative pressure bottle (5), and p1 and p2. S7. Restart the analysis acceleration structure until the desorption rate is lower than the set threshold, and calculate the volume of desorbed gas in real time.
10. The method for determining the gas content in a coal seam using a device according to claim 9, characterized in that, The volume of the coal sample in S6 is calculated using the following formula: coal sample volume ; The gas volume in S7 is calculated using the following formula: Gas Volume ; Where p is the real-time reading of the first pressure sensor (21) or the second pressure sensor (53).