A sealed hole-free coal seam gas pressure measuring device
By using a constant-temperature water bath and a high-precision pressure sensor in the underground environment, combined with helium calibration and pressure application by a piston container, the problem of accurate measurement of coal seam gas pressure in complex underground environments has been solved, achieving high-precision gas pressure measurement and data support.
Patent Information
- Application Number
- CN202521483272.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-16
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-07-16
AI Technical Summary
Existing coal seam gas pressure measuring devices are difficult to measure accurately in the complex underground environment. They are affected by temperature fluctuations and dead volume errors, resulting in inaccurate measurement results, which may mislead coal mine gas disaster early warning and prevention work.
The environment is controlled by a constant temperature water bath. Combined with a high-precision pressure sensor and helium calibration, controllable pressure is applied through a piston container. The high-precision pressure sensor monitors the gas adsorption process. Combined with a rigorous operating procedure, the dead volume and coal sample volume changes are accurately calculated.
It enables accurate measurement of coal seam gas pressure in complex underground environments, reduces temperature fluctuations and dead volume errors, improves the accuracy and reliability of measurement data, and supports coal mine gas prevention and control.
Smart Images
Figure CN224681726U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of gas pressure measurement technology, and in particular to a gas pressure measurement device for coal seams that does not require sealing. Background Technology
[0002] In the coal mining industry, accurate measurement of coal seam gas pressure is a crucial step in preventing gas accidents and ensuring safe production. Coal seam gas pressure is not only an important parameter for assessing coal seam gas content and predicting the risk of gas outbursts, but also a vital basis for formulating gas drainage plans and anti-outburst measures. With the continuous increase in coal mining depth, gas disasters are becoming increasingly severe. Traditional methods for measuring coal seam gas pressure are no longer sufficient to meet the precise measurement needs under complex geological conditions. Therefore, developing efficient, accurate, and reliable non-sealing coal seam gas pressure measuring devices has become an important issue that the industry urgently needs to address. Existing coal seam gas pressure measuring devices mostly employ direct or indirect measurement methods. Direct measurement typically involves placing a pressure sensor directly into the borehole after drilling, sealing the borehole with a sealing device, and reading the coal seam gas pressure after the pressure stabilizes. Indirect measurement involves collecting coal samples, simulating the coal seam environment in a laboratory, measuring parameters such as the gas adsorption characteristics of the coal samples, and then estimating the coal seam gas pressure. These devices mainly rely on mechanical seal structures, conventional pressure sensors, and simple temperature control methods. Their technical principle is based on pressure balance and gas adsorption / desorption theories, obtaining gas pressure data through physical contact and data conversion. However, existing technologies suffer from limitations due to the complex and variable underground environment, significant temperature fluctuations, and the lack of stable temperature control measures in traditional equipment. Furthermore, the methods used for dead volume calibration are rather crude, making it difficult to accurately calculate the dead volume inside the measuring device and connecting pipelines. This results in significant deviations in the data acquired by pressure sensors due to the combined effects of temperature variations and dead volume errors. Consequently, the data fails to accurately reflect coal seam gas pressure, reducing the accuracy and reliability of measurement results and potentially misleading early warning and prevention efforts for coal mine gas disasters, posing a significant threat to coal mine safety. Utility Model Content
[0003] To overcome the above shortcomings, this utility model provides a coal seam gas pressure measuring device that does not require sealing. It aims to improve the existing technology because the underground environment is complex and variable, the temperature fluctuates greatly, and traditional devices lack stable constant temperature environment control measures. At the same time, the methods used in dead volume calibration are relatively crude, making it difficult to accurately calculate the dead volume inside the measuring device and connecting pipelines.
[0004] To achieve the above objectives, this utility model provides the following technical solution: a non-sealing coal seam gas pressure measuring device, comprising a special coal sample container. Special coal sample container, used to hold coal samples, and connected to a desorption device; A constant-temperature water bath is used to contain the special coal sample container. A high-precision pressure sensor, the measuring end of which is connected to the gas path of the special coal sample container; A piston container, connected to the pipeline of the special coal sample container, is used to apply external pressure to the coal sample inside the container; A constant speed and constant pressure pump, the inlet of which is connected to a water cup and an oil cup, and the outlet of which is connected to the piston container; A reference container, the cavity of which is connected to the cavity of the special coal sample container via a valve; A vacuum pump is connected to the cavities of the special coal sample container and the reference container via a valve; The helium cylinder is connected to the gas path of the reference tank via a pressure regulating valve and an inlet valve. And a high-pressure methane cylinder, which is connected to the gas path of the special coal sample container via pressure regulating valve two and gas inlet valve two.
[0005] Furthermore, the constant speed and constant pressure pump is used to draw liquid medium from the water cup or oil cup and inject it into the piston container.
[0006] Furthermore, the desorption device is used in conjunction with the high-precision pressure sensor after the coal sample is loaded into a special coal sample container.
[0007] Furthermore, the helium cylinder, reference container, and special coal sample container are connected by a pressure regulating valve, an inlet valve, and other valves.
[0008] Furthermore, the high-pressure methane cylinder, through pressure regulating valve two and gas inlet valve two, is used to quantitatively inject methane gas into the special coal sample container where the coal sample after volume restoration is located.
[0009] Furthermore, the vacuum pump uses valves to evacuate the internal cavities and connecting pipelines of the special coal sample container and the reference container.
[0010] This utility model has the following beneficial effects: 1. In this invention, a constant-temperature water bath is used to place the reference vessel, the special coal sample vessel, and the connecting pipeline in a stable, constant-temperature environment, effectively avoiding the interference of temperature fluctuations on the experimental results and providing a fundamental guarantee for accurate measurement. Helium is used for dead volume calibration, and a high-precision pressure sensor is used to record pressure changes. Combined with a rigorous operating procedure, the dead volume of the special coal sample vessel and the connecting pipeline can be accurately calculated, greatly improving the accuracy of experimental data, reducing measurement deviations caused by dead volume errors, and ensuring the reliability of subsequent experimental data.
[0011] 2. In this invention, after a fresh coal sample is quickly sealed in a special coal sample container, the desorption device and pressure sensor inside the container monitor the gas quantity and pressure changes under normal pressure in real time, enabling timely acquisition of key data to compensate for gas leakage during the sampling process. The coal core volume restoration system uses a constant-speed, constant-pressure pump to draw liquid and drive a piston container to apply controllable axial pressure to the loose coal sample, restoring the coal sample to a volume close to its original underground volume, effectively solving the problem of dead space volume changes caused by coal sample breakage and expansion.
[0012] 3. In this invention, under the condition of maintaining the original temperature of the coal seam in a constant-temperature water bath, methane gas is injected into a special coal sample container in stages using a "normal pressure quantitative gas replenishment" method, allowing the coal sample and gas to fully interact, thus simulating the real gas adsorption process in the coal seam. A high-precision pressure sensor continuously monitors pressure changes, accurately capturing the pressure equilibrium point during the methane adsorption process of the coal sample. This provides accurate and comprehensive data for studying the gas adsorption characteristics of the coal sample, contributing to a deeper understanding of the gas adsorption laws in coal samples. Attached Figure Description
[0013] Figure 1 This is a three-dimensional structural diagram of a coal seam gas pressure measuring device that does not require sealing, as proposed in this utility model. Legend: 1. Helium cylinder; 2. High-pressure methane cylinder; 3. Pressure regulating valve one; 4. Inlet valve one; 5. Pressure regulating valve two; 6. Inlet valve two; 7. Reference container; 8. High-precision pressure sensor; 9. Desorption device; 10. Vacuum pump; 11. Special coal sample container; 12. Constant temperature water bath; 13. Piston container; 14. Constant speed and constant pressure pump; 15. Water cup; 16. Oil cup; 17. Valve. Detailed Implementation
[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0015] Reference Figure 1 One embodiment of this utility model is a gas pressure measuring device for coal seams that does not require sealing, comprising a special coal sample container 11. Special coal sample container 11, used to hold coal samples, and connected to a desorption device 9; A constant temperature water bath 12 is used to contain a special coal sample container 11. A high-precision pressure sensor 8, the measuring end of which is connected to the gas path of the special coal sample container 11; Piston container 13 is pipe-connected to special coal sample container 11 and is used to apply external pressure to the coal sample inside the container. The constant speed and constant pressure pump 14 has its inlet connected to the water cup 15 and the oil cup 16, and its outlet connected to the piston container 13. Reference tank 7, the cavity of which is connected to the cavity of special coal sample tank 11 via valve 17; Vacuum pump 10 is connected to the cavity of special coal sample container 11 and reference container 7 via valve 17; Helium cylinder 1 is connected to reference tank 7 via pressure regulating valve 3 and inlet valve 4. And the high-pressure methane cylinder 2 is connected to the gas path of the special coal sample tank 11 via the pressure regulating valve 2 5 and the gas inlet valve 2 6.
[0016] Specifically, first, the constant temperature water bath 12 is started and set to the required experimental temperature to ensure that the reference tank 7, the special coal sample tank 11, and the connecting pipeline are in a stable constant temperature environment. After closing all inlet valves, the vacuum pump 10 is started, and the reference tank 7, the special coal sample tank 11, and the pipeline system are evacuated through the control valve 17 to remove residual gas. Then, the helium dead volume is calibrated: the helium cylinder 1 is opened, and helium of a certain pressure is introduced into the reference tank 7 of known volume through the pressure regulating valve 3 and the inlet valve 4. The pressure after stabilization is recorded by the high-precision pressure sensor 8. Then, the valve 17 connecting the reference tank 7 and the empty special coal sample tank 11 is opened. After the helium diffuses to the entire system and the pressure stabilizes again, the high-precision pressure sensor 8 records the pressure at this moment. Based on this, the dead volume V2 of the special coal sample tank 11 and the connecting pipeline is accurately calculated. Fresh coal samples collected underground are quickly loaded into a special coal sample container 11 and sealed. Inside the container, a desorption device 9 and a high-precision pressure sensor 8 monitor and record in real time the amount of gas desorption and pressure changes of the coal sample under normal pressure, obtaining basic data to compensate for gas leakage during sampling. The coal core volume restoration system is then activated: a constant-speed, constant-pressure pump 14 draws liquid from a water cup 15 or an oil cup 16 and injects it into a piston container 13. This drives the piston to apply precise and controllable axial pressure to the loose coal sample in the special coal sample container 11, causing the broken coal particles to be recompacted to near their original underground volume, reducing the change in dead space volume caused by breakage and expansion.
[0017] Reference Figure 1 The constant speed and constant pressure pump 14 is used to extract the liquid medium from the water cup 15 or oil cup 16 and inject it into the piston container 13. The desorption device 9 works in conjunction with the high-precision pressure sensor 8 to connect the special coal sample container 11, helium cylinder 1, reference container 7 and special coal sample container 11 through the pressure regulating valve 1 3, the air inlet valve 1 4 and the valve 17. The high-pressure methane cylinder 2 is used to quantitatively inject methane gas into the special coal sample container 11 where the coal sample has been volume restored through the pressure regulating valve 2 5 and the air inlet valve 2 6. The vacuum pump 10 performs vacuum treatment on the internal cavity and connecting pipeline of the special coal sample container 11 and the reference container 7 through the valve 17.
[0018] Specifically, under the condition of maintaining the original temperature of the coal seam in the constant temperature water bath 12, the high-pressure methane cylinder 2 is opened, and methane gas is injected into the special coal sample container 11 in stages using the pressure regulating valve 5 and the gas inlet valve 6 in a "normal pressure quantitative gas replenishment" manner. After each gas replenishment, the injection is paused until the coal sample has fully adsorbed the methane and the pressure inside the container drops to the equilibrium point. The high-precision pressure sensor 8 continuously monitors this pressure change process. Through the above operation, the accurate determination of the adsorption characteristics of coal seam gas is achieved, providing reliable data support for coal mine gas prevention and control.
[0019] Working Principle: First, the constant temperature water bath 12 is started and set to the required experimental temperature to ensure that the reference tank 7, the special coal sample tank 11, and the connecting pipeline are in a stable constant temperature environment. All inlet valves are closed, and the vacuum pump 10 is started. By controlling the relevant valves 17, a vacuum is evacuated from the reference tank 7, the special coal sample tank 11, and the pipeline system to remove residual gas. Dead volume calibration is performed using helium. Helium cylinder 1 is opened, and helium at a certain pressure is introduced into the reference tank 7 (of known volume) through pressure regulating valve 3 and inlet valve 4. The pressure after stabilization is recorded by the high-precision pressure sensor 8. Subsequently, valve 17 connecting the reference tank 7 and the empty special coal sample tank 11 is opened, allowing helium to diffuse throughout the system. After the pressure stabilizes again, the high-precision pressure sensor 8 records the pressure at this moment. The dead volume V2 of the special coal sample tank 11 and the connecting pipeline can then be accurately calculated, laying the foundation for subsequent calculations. Freshly collected coal samples are quickly loaded into a special coal sample container 11 and sealed. The desorption device 9 and high-precision pressure sensor 8 inside the container begin real-time monitoring and recording of the amount of gas detached from the coal sample under normal pressure and pressure changes. This is the first step in compensating for gas leakage during sampling. The coal core volume restoration system is then activated. A constant-speed, constant-pressure pump 14 draws liquid water or oil from a water cup 15 or an oil cup 16 and injects it into a piston container 13. Driven by the liquid pressure, the piston in the piston container 13 applies a precise and controllable axial pressure to the loose coal sample in the special coal sample container 11, causing the broken coal particles to be recompacted and restored to a volume close to their underground state, thereby minimizing the change in dead space volume caused by breakage and expansion. Under the condition of maintaining the original temperature of the coal seam in the constant temperature water bath 12, the high-pressure methane cylinder 2 is opened. Methane gas is injected into the special coal sample container 11 in stages using a "normal pressure, quantitative gas replenishment" method through the pressure regulating valve 5 and the gas inlet valve 6. Each time gas is replenished, the injection is paused to allow the coal sample and gas to fully interact. During this process, the coal sample will re-adsorb methane, and the gas pressure inside the container will decrease accordingly until it eventually reaches an equilibrium point. A high-precision pressure sensor 8 continuously monitors this pressure change process.
[0020] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A device for measuring the gas pressure of coal seams without sealing the borehole, characterized in that: Including special coal sample containers (11), A special coal sample container (11) is used to hold coal samples and is connected to a desorption device (9); A constant temperature water bath (12) is provided in which the special coal sample container (11) is placed; A high-precision pressure sensor (8) is connected to the gas path of the special coal sample container (11) at its measuring end; A piston container (13) is connected to the special coal sample container (11) via a pipeline and is used to apply external pressure to the coal sample inside the container; A constant speed and constant pressure pump (14) has its inlet connected to a water cup (15) and an oil cup (16), and its outlet connected to the piston container (13); The reference container (7) has its cavity connected to the cavity of the special coal sample container (11) via a valve (17); A vacuum pump (10) is connected to the cavity of the special coal sample container (11) and the reference container (7) via a valve (17); The helium cylinder (1) is connected to the reference tank (7) via the pressure regulating valve (3) and the inlet valve (4); And the high-pressure methane cylinder (2) is connected to the gas path of the special coal sample tank (11) via the pressure regulating valve (5) and the gas inlet valve (6).
2. The gas pressure measuring device for coal seams without sealing as described in claim 1, characterized in that: The constant speed and constant pressure pump (14) is used to draw liquid medium from the water cup (15) or oil cup (16) and inject it into the piston container (13).
3. The coal seam gas pressure measuring device without sealing holes according to claim 1, characterized in that: The desorption device (9) works in conjunction with the high-precision pressure sensor (8) to desorb the coal sample after it has been loaded into the special coal sample container (11).
4. The coal seam gas pressure measuring device without sealing holes according to claim 1, characterized in that: The helium cylinder (1), reference tank (7) and special coal sample tank (11) are connected by pressure regulating valve (3), air inlet valve (4) and valve (17).
5. The gas pressure measuring device for coal seams without sealing as described in claim 1, characterized in that: The high-pressure methane cylinder (2) is used to quantitatively inject methane gas into the special coal sample container (11) containing the coal sample after volume restoration, through the pressure regulating valve (5) and the gas inlet valve (6).
6. The gas pressure measuring device for coal seams without sealing as described in claim 1, characterized in that: The vacuum pump (10) uses valve (17) to evacuate the internal cavities and connecting pipelines of the special coal sample container (11) and the reference container (7).