Coal mining face roof direction drilling inspection device and inspection method

Abstract

A device and method for drilling and investigating the direction of the roof of a coal mining face. The two ends of the investigation tube of the investigation device of the present invention are fixedly connected to a hose through a pipe clamp; the investigation tube is arranged horizontally, and the radial through hole arranged on the upper tube wall is the investigation hole; the investigation device also includes a differential pressure meter, a gas meter, a hose, and a pitot tube, and the differential pressure meter or the gas meter is connected to the hose; the L-shaped pitot tube is located in the investigation tube, and the upper end of the vertical tube of the pitot tube passes through the investigation hole and is connected to the hose; the vertical tube length of the pitot tube is equal to the inner diameter of the investigation tube, and the horizontal tube length is less than the diameter of the investigation tube; the flow direction of the mixed gas measured in the investigation tube is relative to the opening direction of the horizontal tube. Its beneficial effects are that the investigation device has a reasonable structural design and is easy to operate; a multi-point measurement method is used to accurately grasp the gas extraction situation of the roof of the working face, and timely take countermeasures to ensure the safe recovery of the coal mining face, optimize the gas control design, and improve the gas control effect.

Description

Technical Field

[0001] The invention relates to a coal mining working face drilling inspection device, in particular to a coal mining working face roof direction drilling inspection device and inspection method. Background Art

[0002] The extraction effect of the drilling holes in the direction of the roof of the coal mining face is mainly determined by inspecting the drilling site or evaluation unit, but the drilling site or evaluation unit contains dozens or even hundreds of boreholes, and the flow rate and gas concentration at each point in the borehole are different. When the flow rate is too large, the flow rate of the cross section varies greatly, and when the flow rate is too slow, the gas concentration of the cross section varies greatly. At present, the inspection of the extraction borehole is mainly measured by orifice flowmeters or electronic automatic flowmeters. Special equipment is installed for the inspection of a single borehole, which is particularly severe for the borehole throttling, which can reach about 50% at the highest. Therefore, it cannot truly reflect the actual extraction situation of the borehole. If the gas extraction situation of the roof of the working face cannot be grasped in a timely and accurate manner, the safe recovery of the working face will not be guaranteed. Summary of the invention

[0003] In order to overcome the shortcomings of existing drilling inspection devices, such as serious throttling of the borehole, failure to truly reflect the actual extraction situation of the borehole, failure to accurately grasp the gas extraction situation of the working face roof, and failure to ensure safe recovery of the working face, the present invention provides a coal mining working face roof direction drilling inspection device and inspection method.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a coal mining face roof direction drilling investigation device, including an investigation pipe, the two ends of the investigation pipe are fixedly connected with a hose through a pipe clamp to form an extraction pipeline; the investigation pipe is arranged horizontally, and the radial through hole arranged on the upper pipe wall is the investigation hole.

[0005] The survey device also includes a differential pressure meter, a gas meter, a hose, and a Pitot tube. The differential pressure meter or the gas meter is connected to the hose. The L-shaped Pitot tube is located in the survey tube, and the upper end of the vertical tube of the Pitot tube passes through the survey hole and is connected to the hose.

[0006] The Pitot tube is L-shaped, the vertical tube length is equal to the inner diameter of the inspection tube, and the horizontal tube length is less than the diameter of the inspection tube; the axial position of the horizontal tube is the measuring point, and the flow direction of the mixed gas measured in the inspection tube is opposite to the opening direction of the horizontal tube.

[0007] Furthermore, the scale marks arranged along the axial direction of the vertical tube evenly divide the axial direction of the vertical tube into 4 sections or more than 4 sections.

[0008] Furthermore, the scale divides the vertical tube axially into 8 sections, each section is 1 unit, and is numbered 1, 2, 3, ... 8 from top to bottom.

[0009] Furthermore, a radial sealing ring is provided between the Pitot tube and the inspection hole.

[0010] Furthermore, the differential pressure measuring device is any one of a U-shaped water column differential pressure gauge, a mechanical differential pressure gauge, an electronic differential pressure gauge, and a red oil tilt differential pressure gauge.

[0011] Furthermore, when the survey operation is completed, the Pitot tube is pulled out from the survey tube, and then the sealing cover is installed in the survey hole.

[0012] A method for investigating the top plate direction of a coal mining face using a drilling investigation device, the steps of which are as follows:

[0013] A. Connect the differential pressure measuring device to the hose and use the differential pressure measuring device to measure the rapid pressure H in the extraction pipeline;

[0014] B. Remove the differential pressure measuring device, connect the gas measuring device to the hose, and measure the gas concentration C in the extraction pipeline;

[0015] C. Calculate the extraction volume Q per unit area of ​​the measuring point based on the rapid pressure H and gas concentration C measured in steps A and B.

[0016] Q n =V n ×1×C n Formula 1

[0017] Where: V is the flow rate of the gas at the measuring point,

[0018] C is the gas concentration at the measuring point,

[0019] n is the location of the measuring point, that is, the scale value where the vertical tube of the pitot tube intersects with the inspection hole of the inspection tube;

[0020]

[0021] Where: V is the flow rate of the gas at the measuring point,

[0022] H is the velocity pressure at the measuring point,

[0023] n is the location of the measuring point, that is, the scale value where the vertical tube of the pitot tube intersects with the inspection hole of the inspection tube.

[0024] p is the air density in the extraction pipeline, p = 1.29;

[0025] D. According to the flow velocity V value and gas concentration C value in the extraction pipeline, the measurement method of selecting different number of measuring points is adopted.

[0026] When the flow rate in the extraction pipeline is low and the gas concentration is evenly distributed, the two-point measurement method is used;

[0027] When the flow velocity in the extraction pipeline varies greatly and the gas concentration distribution is uneven, the four-point or eight-point measurement method is used.

[0028] Further, the two-point measurement method is as follows:

[0029] First, insert the Pitot tube into the inspection tube to the bottom, then pull it upward to the scale 2 and 6 respectively, and measure the rapid pressure H at the measuring points 2 and 6. 2 , H 6 And gas concentration C 2 , C 6 ;

[0030] After that, the extraction scalar quantity Q of measuring points 2 and 6 is calculated respectively. 2 , Q 6 ;

[0031] Then, the drilling extraction quantity Q is calculated by formula 3:

[0032]

[0033] Further, the four-point measurement method is as follows:

[0034] First, insert the custom Pitot tube into the inspection tube to the bottom, then pull it upward to the scales 1, 3, 5, and 7 respectively, and measure the rapid pressure H at the measuring points 1, 3, 5, and 7. 1 , H 3 , H 5 , H 7 And gas concentration C 1 , C 3 , C 5 , C 7 ;

[0035] After that, the extraction scalar Q of measuring points 1, 3, 5, and 7 are calculated respectively. 1 , Q 3 , Q 5 , Q 7 ;

[0036] Then, the drilling extraction quantity Q is calculated by formula 4:

[0037]

[0038] Further, the eight-point measurement method is as follows:

[0039] First, insert the pitot tube into the inspection tube to the bottom, then pull it upward to the scale of 1 to 8 units respectively, and measure the rapid pressure H at 8 measuring points. 1 ~H 8 And gas concentration C 1 ~C 8 ;

[0040] Afterwards, the extraction scalar quantity Q of the 8 measuring points was calculated respectively. 1 ~Q 8 ;

[0041] Then, the drilling extraction quantity Q is calculated by formula 5:

[0042]

[0043] The beneficial effects of the present invention are that the inspection device has a reasonable structural design and is easy to operate; a multi-point measurement method is used to accurately measure the pure amount of gas extraction in each borehole, accurately grasp the gas extraction situation of the working face roof, and take timely response measures to ensure the safe recovery of the coal mining working face, optimize the gas control design, improve the gas control effect, and avoid the occurrence of gas exceeding the limit accident in the upper corner of the working face due to untimely replacement of the drilling site. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural schematic diagram of a device for drilling and investigating the top plate direction of a coal mining face according to the present invention.

[0045] Figure 2 It is a schematic diagram of the positions of two measuring points in the investigation method of the present invention.

[0046] Figure 3 It is a schematic diagram of the positions of four measuring points in the investigation method of the present invention.

[0047] Figure 4 It is a schematic diagram of the positions of 8 measuring points in the investigation method of the present invention.

[0048] In the figure: 1. differential pressure measuring device, 2. hose, 3. Pitot tube, 4. inspection tube, 5. radial sealing ring, 6. scale, 7. hose, 8. pipe clamp, 9. inspection hole, 10. sealing cover, 11. vertical tube, 12. horizontal tube. DETAILED DESCRIPTION

[0049] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, those skilled in the art should be aware that the present invention is not limited to the specific embodiments listed, and all embodiments should be included in the protection scope of the present invention as long as they conform to the spirit of the present invention.

[0050] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "left", "right", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0051] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] See attached Figure 1 The present invention provides a drilling inspection device for inspecting the top plate direction of a coal mining face, comprising an inspection pipe 4, both ends of which are fixedly connected to a hose 7 through a pipe clamp 8 to form an extraction pipeline; the inspection pipe 4 is arranged horizontally, and a radial through hole arranged on the upper wall of the pipe is an inspection hole 9. When measuring, the pitot tube 3 is inserted into the inspection pipe 4 from the inspection hole 9, and the pitot tube 3 is pulled out from the inspection hole 9 after the measurement is completed.

[0053] The survey device further includes a differential pressure measuring device 1 , a gas measuring device, a hose 2 , and a Pitot tube 3 . One end of the hose 2 is connected to the differential pressure measuring device 1 or the gas measuring device, and the other end of the hose 2 is connected to the Pitot tube 3 .

[0054] The pitot tube 3 is L-shaped, and one end of the horizontal tube 12 of the pitot tube 3 is inserted into the inspection tube 4 from the inspection hole 9 until it falls on the inner tube wall of the inspection tube 4 corresponding to the inspection hole 9. The upper end of the vertical tube 11 of the pitot tube 3 is connected to the hose 2.

[0055] The length of the vertical tube 11 of the L-shaped pitot tube 3 is equal to the inner diameter of the inspection tube 4; the length of the horizontal tube 12 of the L-shaped pitot tube 3 is less than the diameter of the inspection tube 4. The axial position of the horizontal tube 12 is the measuring point, and the flow direction of the mixed gas measured in the inspection tube 4 is opposite to the opening direction of the horizontal tube 12.

[0056] The scale 6 arranged along the axial direction of the vertical tube 11 divides the vertical tube 11 into 4 or more sections. Preferably, the scale 6 divides the vertical tube 11 into 8 sections, each section is 1 unit, and is numbered 1, 2, 3, ... 8 from top to bottom.

[0057] A radial sealing ring 5 is provided between the pitot tube 3 and the inspection hole 9. After obtaining the measuring point data, the pitot tube 3 is pulled out from the inspection hole 9, and then a sealing cover 10 is used to cover the inspection hole 9 to close the inspection hole 9.

[0058] Furthermore, the differential pressure measuring device 1 is any one of a U-shaped water column differential pressure gauge, a mechanical differential pressure gauge, an electronic differential pressure gauge, and a red oil tilt differential pressure gauge, but is not limited to the above.

[0059] A method for investigating the top plate direction of a coal mining face using a drilling investigation device, the steps of which are as follows:

[0060] A. Connect the differential pressure measuring device 1 with the rubber hose 2, and use the differential pressure measuring device 1 to measure the rapid pressure H in the extraction pipeline;

[0061] B. Remove the differential pressure measuring device 1, connect the gas measuring device to the hose 2, and measure the gas concentration C in the extraction pipeline;

[0062] C. Calculate the extraction volume Q per unit area of ​​the measuring point based on the rapid pressure H and gas concentration C measured in steps A and B.

[0063] Q n =V n ×1×C n Formula 1

[0064] Where: V is the flow rate of the gas at the measuring point,

[0065] C is the gas concentration at the measuring point,

[0066] n is the location of the measuring point, i.e., the scale 6 value where the vertical tube 12 of the pitot tube 3 intersects the inspection hole 9 of the inspection tube 4;

[0067]

[0068] Where: V is the flow rate of the gas at the measuring point,

[0069] H is the velocity pressure at the measuring point,

[0070] n is the location of the measuring point, that is, the scale 6 value where the vertical tube 12 of the pitot tube 3 intersects with the inspection hole 9 of the inspection tube 4 (the subscripts in the following formulas are the locations of the measuring points),

[0071] p is the air density in the extraction pipeline, p = 1.29;

[0072] D. According to the flow velocity V value and gas concentration C value in the extraction pipeline, the measurement method of selecting different number of measuring points is adopted.

[0073] When the flow rate in the drainage pipeline is low and the gas concentration is evenly distributed, the two-point measurement method is used; when the flow rate in the drainage pipeline changes greatly and the gas concentration is unevenly distributed, the four-point or eight-point measurement method is used (see Appendix Figure 2 , 3 , 4). Preferably, the greater the flow velocity change in the extraction pipeline and the more uneven the gas concentration distribution, the more measuring points are used, and different weights are assigned according to the number and location of the measuring points.

[0074] Further, the two-point measurement method is as follows:

[0075] First, insert the Pitot tube into the inspection tube to the bottom, then pull it upward to the scale 2 and 6 respectively, and measure the rapid pressure H at the measuring points 2 and 6. 2 , H 6 And gas concentration C 2 , C 6 ;

[0076] After that, the extraction scalar quantity Q of measuring points 2 and 6 is calculated respectively. 2 , Q 6 ;

[0077] Then, the drilling extraction quantity Q is calculated by formula 3:

[0078]

[0079] Further, the four-point measurement method is as follows:

[0080] First, insert the custom Pitot tube into the inspection tube to the bottom, then pull it upward to the scales 1, 3, 5, and 7 respectively, and measure the rapid pressure H at the measuring points 1, 3, 5, and 7. 1 , H 3 , H 5 , H 7 And gas concentration C 1 , C 3 , C 5 , C 7 ;

[0081] After that, the extraction scalar Q of measuring points 1, 3, 5, and 7 are calculated respectively. 1 , Q 3 , Q 5 , Q 7 ;

[0082] Then, the drilling extraction quantity Q is calculated by formula 4:

[0083]

[0084] Further, the eight-point measurement method is as follows:

[0085] First, insert the pitot tube into the inspection tube to the bottom, then pull it upward to the scale of 1 to 8 units respectively, and measure the rapid pressure H at 8 measuring points. 1 ~H 8 And gas concentration C 1 ~C 8 ;

[0086] Afterwards, the extraction scalar quantity Q of the 8 measuring points was calculated respectively. 1 ~Q 8 ;

[0087] Then, the drilling extraction quantity Q is calculated by formula 5:

[0088]

[0089] The present invention may also use other numbers of measuring points in addition to 2, 4, and 8 measuring points according to actual needs.

[0090] As the coal mining face advances, the roof gradually collapses, but it does not immediately communicate with the goaf; when the scope of the roof collapse continues to expand, gas and flow will gradually appear in the new boreholes, and the old boreholes will leak gas from the goaf. If the extraction is not adjusted in time, it will affect the extraction effect and endanger the gas safety of the working face. The extraction conditions of each borehole are different. Through precise inspection of each borehole, the optimal distance of the drill field replacement and the height and width of the roof control can be adjusted in time.

[0091] The coal mining face roof direction drilling inspection device of the present invention has a reasonable structural design and is simple to operate. It can measure the pure amount of gas extraction from a single hole in the same way as measuring the gas concentration of a single hole. According to the changes in the rapid pressure and gas concentration in the pipeline, a method with different numbers of measuring points is adopted to accurately measure the pure amount of gas extraction from each borehole, thereby reducing workload, effectively saving measurement time and improving efficiency.

[0092] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims of this patent.

Claims

1. A method for investigating the top plate direction of a coal mining face by drilling an investigation device, comprising an investigation pipe, characterized in that: The two ends of the inspection pipe are fixedly connected to the hose through a pipe clamp to form an extraction pipeline; the inspection pipe is arranged horizontally, and the radial through hole arranged on the upper wall of the pipe is the inspection hole; The survey device also includes a differential pressure measuring device, a gas measuring device, a hose, and a pitot tube. The differential pressure measuring device or the gas measuring device is connected to the hose. The L-shaped pitot tube is located in the survey tube, and the upper end of the vertical tube of the pitot tube passes through the survey hole and is connected to the hose. The Pitot tube is L-shaped, the length of the vertical tube is equal to the inner diameter of the inspection tube, and the length of the horizontal tube is less than the diameter of the inspection tube; the axial position of the horizontal tube is the measuring point, and the flow direction of the mixed gas measured in the inspection tube is opposite to the opening direction of the horizontal tube; The scale marks arranged along the axial direction of the vertical tube divide the axial direction of the vertical tube into 8 sections, each section is 1 unit, and are numbered 1, 2, 3, ... 8 from top to bottom; A radial sealing ring is provided between the pitot tube and the inspection hole; The differential pressure measuring device is any one of a U-shaped water column differential pressure gauge, a mechanical differential pressure gauge, an electronic differential pressure gauge, and a red oil tilt differential pressure gauge; When the survey operation is completed, the pitot tube is pulled out from the survey tube, and the sealing cover is installed in the survey hole; The steps of the investigation method are as follows: A. Connect the differential pressure measuring device to the hose and use the differential pressure measuring device to measure the rapid pressure H in the extraction pipeline; B. Remove the differential pressure measuring device, connect the gas measuring device to the hose, and measure the gas concentration C in the extraction pipeline; C. Calculate the extraction volume Q per unit area of ​​the measuring point based on the rapid pressure H and gas concentration C measured in steps A and B. Formula 1 Where: V is the flow rate of the gas at the measuring point, C is the gas concentration at the measuring point, n is the location of the measuring point, that is, the scale value where the vertical tube of the pitot tube intersects with the inspection hole of the inspection tube; Formula 2 Where: V is the flow rate of the gas at the measuring point, H is the velocity pressure at the measuring point, n is the location of the measuring point, that is, the scale value where the vertical tube of the pitot tube intersects with the inspection hole of the inspection tube. p is the air density in the extraction pipeline, p=1.29; D. According to the flow velocity V value and gas concentration C value in the extraction pipeline, the measurement method of selecting different number of measuring points is adopted. When the flow rate in the extraction pipeline is low and the gas concentration is evenly distributed, the two-point measurement method is used; When the flow rate in the extraction pipeline varies greatly and the gas concentration distribution is uneven, the four-point or eight-point measurement method is used; The two-point measurement method is to measure the rapid pressure and gas concentration of two measuring points marked 2 and 6 in sequence; The four-point measurement method is to measure the rapid pressure and gas concentration of four measuring points marked 1, 3, 5, and 7 in sequence; The eight-point measurement method is to measure the rapid pressure and gas concentration of eight measuring points marked 1 to 8 in sequence.

2. The investigation method according to claim 1 is characterized in that: The two-point measurement method is as follows: First, insert the Pitot tube into the inspection tube to the bottom, then pull it upward to the scale 2 and 6 respectively, and measure the rapid pressure H2 and H6 and gas concentration C2 and C6 at the measuring points 2 and 6; Afterwards, the pure extraction quantities Q2 and Q6 of measuring points 2 and 6 are calculated respectively; Then, the drilling extraction quantity Q is calculated by formula 3: Formula 3.

3. The investigation method according to claim 1 is characterized in that: The four-point measurement method is as follows: First, insert the custom Pitot tube into the inspection tube to the bottom, then pull it upward to the scales 1, 3, 5, and 7 respectively, and measure the rapid pressure H at the measuring points 1, 3, 5, and 7. 1、 H3, H5, H7 and gas concentrations C1, C3, C5, C7; Afterwards, the extraction pure quantities Q1, Q3, Q5, and Q7 of measuring points 1, 3, 5, and 7 are calculated respectively; Then, the drilling extraction quantity Q is calculated by formula 4: Formula 4.

4. The investigation method according to claim 1 is characterized in that: The eight-point measurement method is as follows: First, insert the Pitot tube into the inspection tube to the bottom, then pull it upward to the scale units 1 to 8 in sequence, and measure the rapid pressure H1 to H8 and gas concentration C1 to C8 at 8 measuring points; Afterwards, the pure extraction quantities Q1 to Q8 of the eight measuring points were calculated respectively; Then, the drilling extraction quantity Q is calculated by formula 5: Formula 5.

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