Coal seam blocking fluid injection device based on multi-stage infiltration
The multi-stage permeation coal seam inhibitor injection device solves the problem of uneven distribution of inhibitor, achieves uniform permeation of inhibitor in the coal seam, improves fire prevention effect and reduces cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SDIC HAMI ENERGY DEV CO LTD
- Filing Date
- 2025-11-20
- Publication Date
- 2026-07-21
AI Technical Summary
Existing coal mine liquid injection methods result in uneven distribution of the inhibitory liquid in the coal seam, making it difficult to effectively prevent spontaneous combustion of coal. Furthermore, the liquid injection process is prone to deviating along the dominant channel, affecting the fire prevention effect.
A multi-stage permeation coal seam inhibitor injection device is adopted. By dividing the injection pipe into three sections along the axial direction, and equipping each injection section with a mechanical constant pressure opening valve and an annular sealing sleeve, the inhibitor is injected in stages and uniformly, ensuring uniform permeation in all areas of the coal seam.
It significantly improves the uniformity of the distribution of the inhibitory liquid in the coal seam, enhances the fire prevention effect, simplifies the usage process, reduces the usage cost, and eliminates the need for an external control system.
Smart Images
Figure CN224532772U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of coal mine safety technology, and in particular to a coal seam inhibition liquid injection device based on multi-stage permeation. Background Technology
[0002] Coal, as a vital basic energy source, occupies a crucial position in the energy structure. However, spontaneous combustion in coal mines has always been one of the major challenges hindering the safe and efficient production of the coal industry. Spontaneous combustion in coal mines not only destroys large amounts of coal resources, causing huge economic losses, but also produces large quantities of toxic and harmful gases, such as carbon monoxide and sulfur dioxide, seriously threatening the lives of underground workers and having a severe impact on the surrounding environment.
[0003] Currently, coal mines commonly use the method of injecting inhibitory fluid into unmined coal seams to prevent spontaneous combustion. Current injection methods mostly employ pipeline delivery. Due to the fixed nozzles and high pressure at a single point, the inhibitory fluid, once inside the coal seam, easily "flows off-center" along the dominant channels in the coal seam fractures, making it difficult to effectively flow into other fractures within the coal body. This results in uneven distribution within the coal seam. Furthermore, due to the borehole inclination angle, the injected inhibitory fluid tends to flow significantly along the inclined direction within the borehole, severely impacting the inhibitory effect. Utility Model Content
[0004] To address the problems existing in the prior art, this utility model aims to provide a coal seam inhibitory liquid injection device based on multi-stage permeation, which can effectively guide the inhibitory liquid to enter the coal body in stages and uniformly, thereby achieving uniform permeation of the inhibitory liquid and significantly improving the fire prevention effect.
[0005] To achieve the above objectives, this utility model proposes a coal seam inhibition liquid injection device based on multi-stage permeation, comprising an injection pump and an injection pipe connected to the injection pump. The injection pipe is used to extend into the borehole. The pipe body is divided into at least three injection sections along the axial direction: a shallow injection section, a middle injection section, and a deep injection section. These injection sections are sequentially connected to form a complete pipe body. Each injection section has several injection ports on its pipe wall. The shallow injection section is located on the outermost side of the pipe body and is used to fill the coal seam area near the borehole opening. The middle injection section... The section connects the shallow injection section and the deep injection section, serving as a transition zone to transmit pressure and inhibitory fluid from the shallow injection section to the deep section. The deep injection section is located at the front end of the pipe body and is used to fill the deep coal seam area of the borehole. Mechanical constant pressure opening valves are provided at the boundaries between adjacent injection sections. In addition to the injection section at the front end of the pipe body, a sealing sleeve is also fitted on the outer wall of the front end of each injection section. The sealing sleeve is an annular elastic bladder, and its bladder body and the outer wall of the injection pipe form a closed cavity. This closed cavity is connected to the interior of the corresponding injection section through a small hole.
[0006] In the above scheme: the sealing sleeve is made of nitrile rubber, which is resistant to high pressure and coal slurry, and its thickness is 5mm. During the injection of coal seam inhibitory fluid, the injection pipe will be subjected to high pressure, especially under multi-stage permeation and step-by-step pressurization injection, where pressure changes are complex. Nitrile rubber has good high-pressure resistance and can withstand the large pressure generated during the injection process without rupture or excessive deformation. This allows the sealing sleeve to maintain a tight fit with the borehole wall under high pressure, ensuring a sealing effect, preventing leakage of inhibitory fluid, and ensuring that the injection process can proceed smoothly according to design requirements.
[0007] In the above scheme: the closed cavity is connected to the interior of the corresponding injection section through two small holes with a diameter of 2mm, so as to realize the pressure transmission between the liquid in the pipe and the closed cavity.
[0008] In the above scheme: multiple rings of injection ports are evenly spaced along the axial direction on the pipe wall of each injection section, and each ring of injection ports includes multiple injection ports evenly distributed in a circumferential direction.
[0009] As the injection pump operates, the inhibitory liquid flows out from the injection ports at various axial positions, avoiding concentrated injection in a specific axial area. This ensures that the coal seam is fully in contact with the inhibitory liquid in the axial direction, effectively inhibiting the coal body throughout the entire axial segment and improving the uniformity of the inhibition effect. The circumferentially distributed injection ports also allow the inhibitory liquid to penetrate evenly in the circumferential direction of the coal seam. As the inhibitory liquid flows out from the injection ports at various circumferential positions, it diffuses evenly into the surrounding coal body.
[0010] In the above scheme: the opening pressure of the mechanical constant pressure opening valve between the shallow injection section and the middle injection section is set to 0.8 to 1.2 MPa, and the opening pressure of the mechanical constant pressure opening valve between the middle injection section and the deep injection section is set to 1.8 to 2.2 MPa. Under this pressure setting, staged injection can be stably achieved.
[0011] The beneficial effects of this utility model are:
[0012] 1. For different depth areas of the coal seam, the injection pipe is divided into multiple injection sections along the axial direction, and a mechanical constant-pressure opening valve is used to achieve staged injection, preventing the inhibitory liquid from "flowing off-center" along the dominant channel. This ensures that the shallow, middle, and deep coal seams are filled sequentially, significantly improving the uniformity of the inhibitory liquid distribution throughout the entire borehole and enhancing the fire prevention effect. 2. During injection, the pressure inside the corresponding injection section increases, and the liquid enters the closed cavity through a small hole. The sealing sleeve expands radially under pressure, thus adhering tightly to the borehole wall and forming a seal. After injection stops, the sealing sleeve loses water and shrinks, detaching from the borehole wall. In other words, the sealing sleeve automatically completes sealing and resetting based on the injection pressure, requiring no additional operation. This simplifies the usage process, ensures a reliable seal against the borehole wall, and prevents backflow and cross-section flow of the inhibitory liquid. Simultaneously, the sealing sleeve is reusable, reducing operating costs and improving economic efficiency. 3. The entire solution relies solely on the innovative design of the valve and sealing structure of the injection pipe itself, requiring no electronic sensors or external control systems. It is simple to manufacture, highly reliable, and suitable for large-scale application in underground coal mines. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the layout of the downhole boreholes.
[0014] Figure 2 This is a schematic diagram of the injection tube. Detailed Implementation
[0015] like Figure 1 As shown in Figure 2, a coal seam inhibition liquid injection device based on multi-stage permeation mainly consists of an injection pump and an injection pipe 2 connected to the injection pump 1. The injection pipe 2 is used to extend into the borehole 3.
[0016] The injection pipe 2 is divided into at least three injection sections along its axial direction: a shallow injection section 21, a middle injection section 22, and a deep injection section 23. These injection sections are connected sequentially to form a complete pipe body. Each injection section has several injection ports 4 on its wall. The shallow injection section 21 is located on the outermost side of the pipe body and is used to fill the coal seam area near the borehole 3 opening. The middle injection section 22 connects the shallow injection section 21 and the deep injection section 23, serving as a transition section and transmitting pressure and inhibitory fluid from the shallow injection to the deeper area. The deep injection section 23 is located at the frontmost end of the pipe body and is used to fill the deep coal seam area of the borehole 3.
[0017] Mechanical constant pressure opening valve 5 is provided at the boundary between two adjacent injection sections. The valve has a preset opening pressure and a pressure threshold of 0-5MPa. It can only be opened when the liquid pressure in the pipe reaches this preset threshold, so as to realize the staged injection of the inhibitory liquid.
[0018] In addition to the injection section at the very front of the tube, a sealing sleeve 6 is also fitted on the outer wall of the outermost part of each injection section. The sealing sleeve 6 is an annular elastic bladder, and its body and the outer wall of the injection tube 2 form a closed cavity. This closed cavity is connected to the interior of the corresponding injection section through a small hole.
[0019] Ideally, the sealing sleeve 6 should be made of nitrile rubber, which is resistant to high pressure and coal slurry, with a sleeve thickness of 5mm. During the injection of the coal seam inhibitory fluid, the injection pipe 2 will be subjected to high pressure, especially under multi-stage permeation and step-by-step pressurization injection, where pressure changes are complex. Nitrile rubber has excellent high-pressure resistance and can withstand the large pressure generated during the injection process without rupture or excessive deformation. This allows the sealing sleeve 6 to maintain a tight fit with the borehole wall 3 under high pressure, ensuring a sealing effect, preventing leakage of the inhibitory fluid, and ensuring that the injection process proceeds smoothly according to design requirements.
[0020] Ideally, the sealed cavity is connected to the interior of the corresponding injection section through two small holes with a diameter of 2 mm, so as to realize the pressure transmission between the liquid inside the tube and the sealed cavity.
[0021] Ideally, multiple rings of injection ports 4 are evenly spaced along the axial direction on the pipe wall of each injection section, and each ring of injection ports 4 includes multiple injection ports 4 evenly distributed in a circumferential direction.
[0022] As the injection pump 1 operates, the inhibitory liquid flows out from the injection ports 4 at various axial positions, avoiding the situation where injection is concentrated in a specific axial area. This ensures that the coal seam is fully in contact with the inhibitory liquid in the axial direction, allowing the coal body in the entire axial section to receive effective inhibitory treatment and improving the uniformity of the inhibitory effect. The circumferentially distributed injection ports 4 also allow the inhibitory liquid to penetrate evenly in the circumferential direction of the coal seam. When the inhibitory liquid flows out from the injection ports 4 at various circumferential positions, it will diffuse evenly into the surrounding coal body.
[0023] A method for injecting coal seam inhibitory fluid based on multi-stage permeation, comprising the aforementioned coal seam inhibitory fluid injection device based on multi-stage permeation, and the steps are as follows:
[0024] S1. Determine the drilling location and proceed with the drilling;
[0025] On the coal face of the intake airway, a row of boreholes 3 are drilled into the coal seam area to be protected from fire. The axis of boreholes 3 is parallel to the coal seam, and their length is greater than the length of the injection pipe 2. The height of each borehole 3 is consistent, and they are evenly spaced along the airflow direction of the intake airway. Specifically, the working face cut is 100m long, the coal seam dip angle is 5°, and the borehole dip angle is also 5°. A total of 10 boreholes 3 are drilled. Based on the required wetting range, the length of borehole 3 is set to 80m, and the diameter is set to 100mm.
[0026] S2, Lower the injection tube;
[0027] The opening pressure of the mechanical constant pressure opening valve 5 between the shallow injection section 21 and the middle injection section 22 is set to 0.8-1.2 MPa, and the opening pressure of the mechanical constant pressure opening valve 5 between the middle injection section 22 and the deep injection section 23 is set to 1.8-2.2 MPa. The injection pipe 2 is pushed along the drilled hole 3 to the predetermined depth to ensure that the three injection sections are located in the coal body section to be injected.
[0028] S3. Sealing the borehole and injecting fluid;
[0029] After the injection pipe 2 is installed and debugged, the borehole 3 is sealed with cement, and the grouting pump 1 is started to inject liquid. The inhibitory liquid flows in from the inlet end of the injection pipe 2 and flows out from the outlet hole 4. During the injection, the pressure inside the pipe corresponding to the injection section increases, and the liquid enters the closed cavity through the small hole. The bladder of the sealing sleeve 6 expands radially under pressure, thus tightly adhering to the inner wall of the borehole 3 to form a sealed state.
[0030] In the initial stage of injection, when the pressure inside the pipe is lower than the set opening pressure of the mechanical constant pressure opening valve 5 between the shallow injection section 21 and the middle injection section 22, the mechanical constant pressure opening valve 5 is closed, and the inhibitory liquid only flows within the shallow injection section 21 and permeates into the surrounding coal body; when the coal body area corresponding to the shallow injection section 21 is filled, when the pressure inside the pipe rises to the set opening pressure of the mechanical constant pressure opening valve 5 between the shallow injection section 21 and the middle injection section 22, the mechanical constant pressure opening valve 5 opens, and the inhibitory liquid enters the middle injection section 22.
[0031] When the coal body area corresponding to the middle injection section 22 is filled, the pressure inside the pipe rises to the set opening pressure of the mechanical constant pressure opening valve 5 between the middle injection section 22 and the deep injection section 23. The mechanical constant pressure opening valve 5 opens, and the inhibitory liquid enters the deep injection section 23, thereby achieving uniform injection throughout the entire borehole depth 3.
[0032] S4. Complete the liquid injection and tube recovery;
[0033] When the coal mining face is about to advance to the position of borehole 3, stop the injection and break the sealing cement. After the injection stops, the sealing sleeve 6 loses water and shrinks, separating from the inner wall of borehole 3. Then, pull out the injection pipe 2 from borehole 3, clean the coal sludge on the surface of the sealing sleeve 6 and keep it for subsequent recycling.
[0034] Ideally, the opening pressure of the mechanical constant pressure opening valve 5 between the shallow injection section 21 and the middle injection section 22 should be set to 1 MPa, and the opening pressure of the mechanical constant pressure opening valve 5 between the middle injection section 22 and the deep injection section 23 should be set to 2 MPa. Under these pressure settings, staged injection can be stably achieved.
Claims
1. A coal seam blocking fluid injection device based on multi-stage penetration, comprising an injection pump and (1) an injection pipe (2) connected to the injection pump (1), the injection pipe (2) is used to extend into the inside of a borehole (3), characterized in that: The injection pipe (2) is divided into at least three injection sections along the axial direction: a shallow injection section (21), a middle injection section (22), and a deep injection section (23). These injection sections are connected sequentially to form a complete pipe body. Each injection section has several injection ports (4) on its pipe wall. The shallow injection section (21) is located on the outermost side of the pipe body and is used to fill the coal seam area near the borehole (3). The middle injection section (22) is connected between the shallow injection section (21) and the deep injection section (23) as a transition section. After receiving the shallow injection, the pressure and inhibitory liquid are transmitted to the deep part; the deep injection section (23) is located at the front end of the pipe body and is used to fill the deep coal body area of the borehole (3); a mechanical constant pressure opening valve (5) is provided at the boundary between two adjacent injection sections; in addition to the injection section at the front end of the pipe body, a sealing sleeve (6) is also fitted on the outer wall of the front end of each injection section. The sealing sleeve (6) is an annular elastic bladder, and its bladder body and the outer wall of the injection pipe (2) form a closed cavity. The closed cavity is connected to the interior of the corresponding injection section through a small hole.
2. The coal bed hibernation fluid injection device based on multi-stage infiltration according to claim 1, characterized in that: The sealing sleeve (6) is made of nitrile rubber that is resistant to high pressure and coal slurry, and its thickness is 5mm.
3. The coal bed hibernation fluid injection device based on multi-stage infiltration according to claim 2, characterized in that: The enclosed cavity is connected to the interior of the corresponding injection section through two small holes with a diameter of 2 mm.
4. The multi-stage infiltration based coal bed mitigation fluid injection apparatus of claim 1, wherein: Each injection section has multiple ring injection ports (4) evenly spaced along the axial direction on the pipe wall. Each ring injection port (4) includes multiple injection ports (4) evenly distributed in a circumferential direction.
5. The multi-stage infiltration based coal bed mitigation fluid injection apparatus of claim 1, wherein: The opening pressure of the mechanical constant pressure opening valve (5) between the shallow injection section (21) and the middle injection section (22) is set to 0.8 to 1.2 MPa, and the opening pressure of the mechanical constant pressure opening valve (5) between the middle injection section (22) and the deep injection section (23) is set to 1.8 to 2.2 MPa.