Sealing device

Abstract

The present application relates to the field of coal seam grouting hole sealing, in particular to a hole sealing device, comprising a grouting pipe and two hole sealing bags, the hole sealing bags are annular, the hole sealing bags are sleeved on the extraction pipe and bonded with the extraction pipe, the grouting pipe penetrates the hole sealing bags, and the two hole sealing bags are connected through the grouting pipe, the hole sealing bags are sealed with the grouting pipe through a clamp, and the right end of the grouting pipe is plugged with a plug; a blasting valve is installed on the grouting pipe between the two hole sealing bags, a one-way valve is also installed on the grouting pipe, and the one-way valve is located in the hole sealing bag. When the technical scheme is adopted, the hole sealing effect is improved.

Description

[0001] This application is a divisional application of application number 2021110164722, filed on August 31, 2021, entitled "A Radial Expansion Active Pressure Grouting Sealing Process". Technical Field

[0002] This invention relates to the field of coal seam grouting and sealing, and more specifically to sealing devices. Background Technology

[0003] Coal seam gas drainage is one of the fundamental measures to solve coal mine gas accidents, and effective sealing of coal seam boreholes is key to efficient drainage. Currently, the common method for sealing boreholes is to insert a drainage pipe into the borehole and then inflate a sealing bag fitted over the pipe. The inflated sealing bag then seals the borehole. However, for relatively fragmented and soft coal seams, there are micro-cracks around the borehole, making the sealing bag less effective and compromising the sealing efficiency, thus affecting gas drainage. Summary of the Invention

[0004] The purpose of this invention is to provide a process for improving the sealing effect by means of radial expansion and active pressure bearing.

[0005] To achieve the above objectives, the present invention provides a radial expansion active pressure-bearing grouting sealing process, comprising the following steps:

[0006] Step 1: Drill gas extraction boreholes and clean the boreholes;

[0007] Step 2: Insert the extraction pipe and sealing device into the borehole;

[0008] Step 3: Use a pumping device to fill the sealing device and the sealing section of the drilled hole with a mixture of expanding pressure-bearing material and water.

[0009] The technical advantages of this scheme are as follows: After drilling is completed, clean water or high-pressure gas is used to clean the impurities inside the borehole, which helps to ensure the quality of the mixed slurry of the expandable pressure-bearing material and water during pouring. The mixed slurry is injected under pressure into the fissures around the borehole through a pumping device, which provides active support to the coal and rock mass around the borehole. After the expandable pressure-bearing material effectively penetrates into the coal fissures and undergoes an expansion and hardening reaction, the borehole is sealed. The sealing effect is good, which helps to improve the gas extraction effect.

[0010] Furthermore, the expandable pressure-bearing material mentioned in step three comprises the following components by mass percentage: cement 48-55%, fly ash 8-10%, calcium sulfate 8-9%, calcium carbonate 18-20%, silica 8-9%, methylcellulose 0.2-0.3%, crack-resistant agent 0.8-1.8%, water-reducing agent 1-2%, iron powder 0.8-1%, aluminum powder 0.8-1%, and oxalic acid 0.2-0.4%. The technical advantages of this solution are: during the injection of the mixture of this expandable pressure-bearing material and water into the borehole sealing section, the injectability, fluidity, and on-site operability are all good; simultaneously, after filling the borehole sealing section, the expansion stabilization time is short, and there is no shrinkage or deformation after expansion, ensuring that the material can penetrate into the cracks around the borehole, effectively sealing micro-cracks; moreover, after expansion and solidification, it has good flame retardancy and antistatic properties.

[0011] Furthermore, the expandable pressure-bearing material is mixed with water at a water-cement ratio of 0.6 to form a slurry. The technical advantages of this solution are: the injectability, fluidity, and on-site operability of the slurry made from the expandable pressure-bearing material and water at this water-cement ratio are all superior.

[0012] Furthermore, the sealing device described in step two includes a grouting pipe and several sealing bags. The sealing bags are fitted onto the extraction pipe. The grouting pipe passes through the sealing bags and adjacent sealing bags are connected by the grouting pipe. A burst valve is provided on the grouting pipe on the adjacent sealing bags. A one-way valve is also provided on the grouting pipe. The one-way valve is located inside the sealing bag. The technical effect of this solution is as follows: After the mixture of expanding pressure-bearing material and water is injected into the grouting pipe, the one-way valve inside the sealing bag opens, and the mixed slurry accumulates inside the sealing bag. The volume of the sealing bag and the pressure of the slurry inside continuously increase, and the sealing bag tightly adheres to the side wall of the borehole. When the pressure inside the sealing bag reaches a certain value, the burst valve outside the sealing bag opens, and the mixed slurry continuously enters the sealed section between the two sealing bags. Grouting stops when the grouting pressure reaches the required grouting pressure. As the mixed slurry continuously enters the sealing section, the borehole is squeezed and expanded by the mixed slurry. At this time, there will be gaps between the sealing bag and the side wall of the borehole. Through the setting of the one-way valve, as the borehole expands, the mixed slurry will enter the sealing bag through the one-way valve, causing the sealing bag to continue to expand and tightly adhere to the side wall of the borehole, which is more conducive to improving the sealing effect.

[0013] Furthermore, hot air is circulated inside the extraction pipe. The technical effect of this scheme is that after the hot air enters the borehole and coal seam through the extraction pipe, it helps to convert adsorbed gas into free gas, which is beneficial to improving the gas extraction effect.

[0014] Furthermore, the pumping device described in step three includes a mixing tank and a pneumatic agitator and a pneumatic grouting pump installed inside the mixing tank. The pneumatic grouting pump is connected to the grouting pipe. The technical advantage of this solution is that the pneumatic agitator stirs the mixed slurry in the mixing tank, which helps to improve the working efficiency and ease of use of the pneumatic grouting pump. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the sealing device according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the pumping device according to an embodiment of the present invention;

[0017] Figure 3 Diagram showing the expansion performance parameters of the expandable pressure-bearing material;

[0018] Figure 4 The image shows the expansion effect of an expansion-bearing material (left: expansion-bearing material; right: ordinary expansion cement).

[0019] Figure 5 A three-dimensional schematic diagram of the extraction pipe and the heat injection pipe;

[0020] Figure 6 for Figure 5 A magnified view of a portion of point A in the middle. Detailed Implementation

[0021] The following detailed description illustrates the specific implementation method:

[0022] The reference numerals in the accompanying drawings of the instruction manual include: 1. Grouting pipe; 2. Clamp; 3. Sealing bag; 4. One-way valve; 5. Bursting valve; 6. Plug; 7. Mixing tank; 8. Pneumatic mixer; 9. Pneumatic grouting pump; 10. Compressed air interface; 11. Heat injection pipe; 12. Extraction pipe; 13. Pushing block; 14. Slide groove; 15. Arc groove; 16. Washer; 17. Channel; 18. Pushing strip.

[0023] Example 1:

[0024] A radial expansion active pressure-bearing grouting sealing process includes the following steps:

[0025] Step 1: Construct gas extraction boreholes according to design requirements and clean the boreholes with clean water or high-pressure gas.

[0026] Step Two: [The sentence is incomplete and requires more context to be translated accurately.] Figure 1 The extraction pipe 12 and sealing device shown are inserted into the borehole; the sealing device includes a grouting pipe 1 and two sealing bags 3. The sealing bags 3 are annular in right view. The sealing bags 3 are fitted onto the extraction pipe 12 and are bonded to the extraction pipe 12. The grouting pipe 1 passes through the sealing bags 3, and the two sealing bags 3 are connected by the grouting pipe 1. The sealing bags 3 are sealed to the grouting pipe 1 by a clamp 2. The right end of the grouting pipe 1 is sealed with a plug 6. A burst valve 5 is installed on the grouting pipe 1 between the two sealing bags 3. A one-way valve 4 is also installed on the grouting pipe 1. The one-way valve 4 is located inside the sealing bags 3.

[0027] Step 3: Using a pumping device, fill the sealing bag 3 and the sealing section of the drilled hole with a mixture of expanding pressure-bearing material and water; the sealing section is the area between the two sealing bags 3; where, for example... Figure 2 As shown, the pumping device includes a mixing tank 7 and a pneumatic agitator 8 and a pneumatic grouting pump 9 installed inside the mixing tank 7. The pneumatic grouting pump 9 includes a sealed outer shell, a cylinder body, a pump rod, a guide piston, an air inlet, and a grout outlet. The grout outlet is connected to the grouting pipe 1 through a pipe. The pneumatic agitator 8 is bolted to the mixing tank 7. The mixing tank 7 is provided with a compressed air interface 10. The compressed air pipe in the coal mine is connected to the compressed air interface 10, and the compressed air interface 10 is connected to the air inlet of the pneumatic grouting pump 9 and the pneumatic agitator 8. During operation, the pressure difference of the compressed air in the mine is used to make the piston in the pump rod move up and down, which drives the guide piston to open and close, thereby playing the role of lifting and feeding materials.

[0028] In addition, the raw materials for the expansion bearing material include the following components by mass percentage: cement 48-55%, fly ash 8-10%, calcium sulfate 8-9%, calcium carbonate 18-20%, silica 8-9%, methylcellulose 0.2-0.3%, crack-resistant agent 0.8-1.8%, water-reducing agent 1-2%, iron powder 0.8-1%, aluminum powder 0.8-1%, and oxalic acid 0.2-0.4%; specifically in this embodiment, it is cement 53%, fly ash 8%, calcium sulfate 8%, and calcium carbonate 19%. The ingredients are: 8% silica, 0.2% methylcellulose, 1% crack-resistant agent, 1% water-reducing agent, 0.8% iron powder, 0.8% aluminum powder, and 0.2% oxalic acid. Specifically, for example, if 100g of raw materials are needed to fill the sealing bag 3 and the sealing section of the drilled hole, then the ingredients are: 53g cement, 8g fly ash, 8g calcium sulfate, 19g calcium carbonate, 8g silica, 0.2g methylcellulose, 1g crack-resistant agent, 1g water-reducing agent, 0.8g iron powder, 0.8g aluminum powder, and 0.2g oxalic acid.

[0029] The expansion-bearing material was mixed evenly with water at different mass ratios, and the viscosity of the different mixtures was tested using the drop weight method. The viscosity trends are shown in Table 1.

[0030] Table 1 Viscosity Test Parameters for Expansive Pressure-Bearing Materials

[0031] 0.4 3.1 0.7 12.6 0.45 3.9 0.75 12.7 0.5 8.6 0.8 12.7 0.55 11.2 0.85 12.8 0.6 12.4 0.9 12.8 0.65 12.6 0.95 12.8

[0032] Therefore, it can be concluded that when the water-cement ratio of the expansive pressure-bearing material is 0.6, the injectability, fluidity, and on-site operability of the mixed slurry are all superior.

[0033] The expansion performance of the expandable pressure-bearing material was determined experimentally. The material and water were mixed at a water-cement ratio of 0.6, and 150 mL of the mixture was placed in a 500 mL beaker. The initial volume V0 was recorded, and the volume was recorded every 5 minutes as V1, V2, V3, ..., Vn (Vn being the final stable value). The expansion rate was then calculated as (Vn - V0) / V0. The test parameters for the expansion process are shown in [the table below]. Figure 3 .Depend on Figure 3 It is evident that the expansion reaction time of the expansion pressure-bearing material is 18 to 50 minutes after the batching is completed. The expansion stabilization time is short, and the material does not shrink or deform after expansion, ensuring that the material can penetrate into the cracks around the borehole and effectively seal the micro-cracks.

[0034] To gain a more comprehensive and detailed understanding of the various performance parameters of the new sealing material, the parameters of the new sealing material were measured according to relevant standards and specifications such as JGJ70-90 "Basic Performance Test Methods for Mortar", MT113-1995 "General Test Methods and Judgment Rules for Flame Retardant and Antistatic Polymer Products Used in Coal Mines", and GB / T 17671-1999 "Test Methods for Mortar Strength". The results are shown in Table 2. The expansion effect of this expansion pressure-bearing material after solidification is as follows: Figure 4 As shown.

[0035] Table 2 Performance Parameters of Expandable Pressure-Bearing Materials

[0036]

[0037]

[0038] Step 4: Grouting completed, pumping equipment cleaned, site tidied.

[0039] Example 2:

[0040] Based on the sealing process in the embodiment, the sealing process in this embodiment also includes introducing hot air into the extraction pipe 12 after grouting is completed. Specifically, the hot air is introduced into the heat injection pipe 11 in the coal mine through a heating device such as an air heater. After the extraction pipe 12 is sent into the borehole, the extraction pipe 12 is connected to the heat injection pipe 11. Usually, in order to improve the sealing performance of the connection, a sealing ring needs to be set on the extraction pipe 12. This makes the connection between the extraction pipe 12 and the heat injection pipe 11 very difficult.

[0041] Therefore, as Figure 5 As shown, several booster blocks 13 (only two are shown in the figure) are welded circumferentially to the outer side wall of the extraction pipe 12 at its head end. Figure 6As shown, the inner wall of the left end of the heat injection pipe 11 has an annular groove and a number of sliding grooves 14 and arc-shaped grooves 15 that match the number of booster blocks 13. The right end of the heat injection pipe 11 is connected to the air heater through a pipe. The annular groove is used to accommodate the gasket 16. The two ends of the gasket 16 are in close contact with the side wall of the annular groove, and the outer wall of the gasket 16 is spaced from the bottom of the annular groove.

[0042] like Figure 6 As shown, the slide groove 14 and the arc groove 15 are connected. The right side wall of the arc groove 15 is inclined with a channel 17 connecting to the annular groove. The left side wall of the arc groove 15 is also opened with a channel 17. A booster strip 18 is slidably arranged in the channel 17. The right end of the booster strip 18 is located in the annular groove. During the upward movement of the booster strip 18, it can contact the washer 16. The left end of the booster strip 18 is located in the channel 17 on the left side wall of the arc groove 15. The booster block 13 can rotate upward in the arc groove 15 and contact the booster strip 18. A spring is provided between the booster strip 18 and the upper side wall of the channel 17. One end of the spring is welded to the upper side wall of the channel 17, and the other end of the spring is welded to the booster strip 18.

[0043] After inserting the booster block 13 on the extraction pipe 12 into the slide groove 14 along the axial direction of the heat injection pipe 11, rotate the extraction pipe 12 clockwise to make the booster block 13 rotate along the arc groove 15 and push the booster strip 18 to move. After the booster strip 18 contacts the gasket 16, the gasket 16 retracts and fits tightly against the extraction pipe 12, thereby facilitating the connection between the extraction pipe 12 and the heat injection pipe 11 and improving the connection sealing.

[0044] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics in the solutions is not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A hole sealing device, characterized by: The system includes a grouting pipe and two sealing bags. The sealing bags are annular and are fitted onto and bonded to the extraction pipe. The grouting pipe passes through the sealing bags, and the two sealing bags are connected by the grouting pipe. The sealing bags are sealed to the grouting pipe by clamps, and a plug is installed at the right end of the grouting pipe. A burst valve is installed on the grouting pipe between the two sealing bags, and a one-way valve is also installed on the grouting pipe, located inside the sealing bag. The process involves drilling a gas extraction borehole and inserting an extraction pipe into it. A pumping device is used to fill the sealing device and the sealing section of the borehole with a mixture of expanding pressure-bearing material and water. After grouting, hot air is introduced into the extraction pipe. This hot air is then introduced into a heat injection pipe within the coal mine via a heating device. After the extraction pipe is inserted into the borehole, it is connected to the heat injection pipe. A booster block is welded circumferentially to the outer wall of the extraction pipe at its head. An annular groove and a matching number of sliding grooves and arc-shaped grooves are formed on the inner wall of the left end of the heat injection pipe. The right end of the heat injection pipe is connected to an air heater via a pipe. The annular groove is used to accommodate gaskets. Both ends of the gasket are in close contact with the sidewalls of the annular groove, and the outer wall of the gasket is spaced from the bottom of the annular groove. The sliding groove and the arc groove are connected. The right side wall of the arc groove is inclined with a channel connecting to the annular groove, and the left side wall of the arc groove is also opened with a channel. A booster is slidably installed in the channel. The right end of the booster is located in the annular groove, and the booster can contact the gasket when it moves upward. The left end of the booster is located in the channel of the left side wall of the arc groove. The booster can contact the booster when it rotates upward in the arc groove. A spring is installed between the booster and the upper sidewall of the channel. One end of the spring is welded to the upper sidewall of the channel, and the other end of the spring is welded to the booster.

2. The hole closure device of claim 1, wherein: The aforementioned expansion pressure-bearing material comprises the following components by mass percentage: cement 48-55%, fly ash 8-10%, calcium sulfate 8-9%, calcium carbonate 18-20%, silicon dioxide 8-9%, methylcellulose 0.2-0.3%, crack-resistant agent 0.8-1.8%, water-reducing agent 1-2%, iron powder 0.8-1%, aluminum powder 0.8-1%, and oxalic acid 0.2-0.4%.

3. The hole closure device of claim 2, wherein: The expandable pressure-bearing material and water are mixed into a slurry at a water-cement ratio of 0.

6.

4. The hole closure device of claim 1, wherein: The pumping device includes a mixing tank and a pneumatic agitator and a pneumatic grouting pump installed inside the mixing tank. The pneumatic grouting pump is connected to the grouting pipe.

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