Automatic control device for gas drainage and nitrogen injection pressure equalization in goaf of underground coal mine

Abstract

The invention discloses an automatic control device for gas drainage and nitrogen injection pressure equalization in the gob area of a coal mine. The inner ends of the gas drainage pipe and the nitrogen injection pipe respectively penetrate through the isolation wall and communicate with the gob area. A first one-way valve and a second one-way valve are respectively installed on the gas drainage pipe and the nitrogen injection pipe. The observation pipe communicates with the observation hole, and the outer end of the observation pipe is respectively communicated with the sealed pipe grooves of the first U-shaped water tank and the second U-shaped water tank through a connecting pipe. A first floating ball and a second floating ball are respectively arranged in the open pipe grooves of the first U-shaped water tank and the second U-shaped water tank. The first floating ball and the second floating ball respectively control the opening and closing of the first one-way valve and the second one-way valve through a first rope and a second rope. The first U-shaped water tank and the second U-shaped water tank are respectively located below the first one-way valve and the second one-way valve. The invention does not require external power assistance such as a power supply, and the control is reliable and flexible, solving the problems of large changes in the sealed pressure difference and the inability to timely switch and adjust gas drainage and nitrogen injection pressure equalization, which brings potential hazards of gas and spontaneous combustion.

Description

Technical Field

[0001] The present invention relates to coal mine gas drainage, and in particular to an automatic control device for gas drainage and nitrogen injection pressure equalization in the gob area of a coal mine underground. Background Art

[0002] The gob sealing in a coal mine is the key point of coal mine ventilation and gas prevention management. The function of gob sealing is to seal the passage between the abandoned coal mining face and the underground roadway, and it is mostly constructed by concrete bricklaying or pouring. In the gob area of a high-gas coal mine, there is a large amount of gas accumulated, and at the same time, the residual coal in the gob area has the risk of spontaneous combustion. Affected by factors such as air pressure changes, the growth and recession of water accumulation in the gob area, stope pressure changes, roof collapse and caving in the gob area, the pressure difference between the inside and outside of the gob area changes very greatly. In mountainous areas and high-altitude areas, the pressure difference change is particularly obvious, and sometimes the pressure difference change value reaches more than 1000 Pa, which brings difficulties to preventing gob gas from gushing out and preventing spontaneous combustion.

[0003] When the pressure in the gob area is higher than the pressure in the mine roadway, a large amount of gas in the gob area gushes out, causing the gas outside the seal to exceed the limit. When the pressure in the gob seal is lower than the pressure in the mine roadway, a large amount of air leaks into the gob area, and the residual coal in the gob area is oxidized, forming a hidden danger of spontaneous combustion.

[0004] When gob gas gushes out, it can be treated by draining the gas inside the seal. When air leaks into the gob area, nitrogen injection can be used to inert the gas in the gob area to achieve pressure equalization. However, due to the large change in the pressure difference between the inside and outside of the gob area, if the gas drainage and nitrogen injection are not adjusted in time, it will have the opposite effect. For example: at the beginning, the pressure in the gob area is high, and in order to control gas gushing, the method of draining gas is adopted. However, the pressure in the gob area suddenly becomes low, and continuous gas extraction instead increases the air leakage volume in the gob area, increasing the degree of hidden danger of spontaneous combustion. Another example: when the pressure in the gob area is low, the method of nitrogen injection inerting and pressure equalization is adopted. However, the pressure in the gob area suddenly becomes high, and nitrogen injection increases the pressure in the gob area, resulting in more gas gushing out.

[0005] Therefore, although gas drainage and nitrogen injection are both very necessary safety measures, if the switching adjustment cannot be made in time according to the change of the seal pressure difference, it will form a greater gas gushing and hidden danger of natural fire prevention.

[0006] Therefore, due to the large change in the pressure difference between the inside and outside of the gob area, a control device that can automatically switch between the two measures of gas extraction and nitrogen injection in time according to the change of the pressure difference between the inside and outside of the gob area is needed.

[0007] The Chinese utility model patent with the authorization announcement number CN208845159 discloses a gas extraction device for nitrogen injection and permeability enhancement in coal mines. The invention includes a liquid nitrogen injection system, a nitrogen-methane extraction system, a nitrogen-methane separation system, a nitrogen purification system, and a nitrogen liquefaction circulation system. This invention cannot automatically switch between extraction and nitrogen injection according to the pressure difference change inside and outside the goaf. Summary of the Invention

[0008] The purpose of the present invention is to solve the above technical problems, and to provide an automatic control device for balanced pressure of gas drainage and nitrogen injection in the goaf of coal mines, so as to improve safety.

[0009] The technical solution adopted by the present invention to solve its technical problems is:

[0010] An automatic control device for balanced pressure of gas drainage and nitrogen injection in the goaf of coal mines. There is a partition wall between the roadway and the goaf. The inner ends of the gas drainage pipe and the nitrogen injection pipe respectively pass through the partition wall and communicate with the goaf. An observation hole is opened on the partition wall. The gas drainage pipe and the nitrogen injection pipe are respectively installed with a first one-way valve and a second one-way valve. The observation pipe communicates with the observation hole. The outer end of the observation pipe is respectively communicated with the sealed pipe grooves of the first U-shaped water tank and the second U-shaped water tank through a connecting pipe. The open pipe grooves of the first U-shaped water tank and the second U-shaped water tank are respectively provided with a first floating ball and a second floating ball. The first floating ball and the second floating ball respectively control the opening and closing of the first one-way valve and the second one-way valve through a first rope and a second rope. The first U-shaped water tank and the second U-shaped water tank are respectively located below the first one-way valve and the second one-way valve.

[0011] Compared with the prior art, the present invention adopting the above technical solution has the beneficial effects that:

[0012] The structure is simple, the cost is low, no external power such as electricity is required for assistance, it is safe and stable, the control is reliable and flexible, the installation is convenient, and it solves the problems of large change in sealed pressure difference and the hidden dangers of gas and spontaneous combustion caused by the failure to timely switch and adjust the balanced pressure of extraction and nitrogen injection.

[0013] Furthermore, the optimized solution of the present invention is:

[0014] The gas drainage pipe is installed with a first one-way valve chamber. The gas drainage pipe includes an inner gas drainage pipe and an outer gas drainage pipe. The inner end of the first one-way valve chamber communicates with the outer end of the inner gas drainage pipe. The inner end of the outer gas drainage pipe is placed in the first one-way valve chamber and a first one-way valve is installed.

[0015] The first one-way valve includes a one-way valve plate, a hinge seat and a pin shaft. The one-way valve plate seals the inner pipe orifice of the outer gas drainage pipe. The upper end of the one-way valve plate is hinged to the hinge seat through the pin shaft, and the hinge seat is fixedly connected to the upper circumferential surface of the outer gas drainage pipe. The outer plate surface of the one-way valve plate is bolted to one end of the first rope, and the other end of the first rope successively bypasses the upper fixed pulley in the first one-way valve chamber, the lower fixed pulley at the bottom of the first U-shaped water tank and is connected to the bottom of the floating ball.

[0016] The nitrogen injection pipe is installed with a second one-way valve chamber. The nitrogen injection pipe includes an inner nitrogen injection pipe and an outer nitrogen injection pipe. The outer end of the inner nitrogen injection pipe extends into the second one-way valve chamber and installs a second one-way valve, and the inner end of the outer nitrogen injection pipe is communicated with the outer end of the second one-way valve chamber.

[0017] The second one-way valve is installed at the outer pipe orifice of the inner nitrogen injection pipe. The one-way valve plate of the second one-way valve is bolted to the second rope, and the second rope bypasses the upper fixed pulley in the second one-way valve chamber and is connected to the upper part of the second floating ball.

[0018] The one-way valve plate of the first one-way valve is provided with a wedge-shaped vent hole, and a pressure relief plug is arranged in the wedge-shaped vent hole.

[0019] The observation pipe is communicated with the U-shaped water column gauge. Description of the Drawings

[0020] Figure 1 is a schematic diagram of gas drainage in an embodiment of the present invention;

[0021] Figure 2 is Figure 1 an enlarged schematic diagram of part A in;

[0022] Figure 3 is a schematic diagram of nitrogen injection in an embodiment of the present invention;

[0023] Figure 4 is Figure 3 an enlarged schematic diagram of part B in.

[0024] In the figure: goaf 1; isolation wall 2; roadway 3; gas drainage pipe 4; inner gas drainage pipe 4-1; outer gas drainage pipe 4-2; first one-way valve chamber 5; upper fixed pulley 5-1; first one-way valve 6; one-way valve plate 6-1; hinge seat 6-2; pin shaft 6-3; protrusion 6-4; vent hole 6-5; pressure relief plug 6-6; limit pin 6-7; nitrogen injection pipe 7; inner nitrogen injection pipe 7-1; outer nitrogen injection pipe 7-2; observation pipe 8; U-shaped water column gauge 8-1; first U-shaped water tank 9; closed pipe groove 9-1; horizontal pipe groove 9-2; open pipe groove 9-3; floating ball 9-4; lower fixed pulley 9-5; connecting pipe 10; first rope 11; second one-way valve chamber 12; second one-way valve 13; second U-shaped water tank 14; second rope 15. Detailed Embodiment

[0025] The present invention will be further described in detail below in conjunction with the drawings and embodiments.

[0026] Refer to Figures 1 - 4 , this embodiment is an automatic control device for gas drainage and nitrogen injection pressure equalization in the gob area of a coal mine. A partition wall 2 is built between the gob area 1 and the roadway 3. The gas drainage pipe 4 and the nitrogen injection pipe 7 are arranged at the top of the roadway 3, the nitrogen injection pipe 7 is located below the gas drainage pipe 4, and the inner ends of the gas drainage pipe 4 and the nitrogen injection pipe 7 respectively pass through the partition wall 2 and communicate with the gob area 1. A through observation hole 2-1 is opened in the partition wall 2, an observation pipe 8 is installed in the observation hole 2-1, the observation pipe 8 is located between the gas drainage pipe 4 and the nitrogen injection pipe 7, and a U-shaped water column gauge 8-1 communicated with it is installed at the outer end of the observation pipe 8.

[0027] A first one-way valve chamber 5 is installed on the outer side of the partition wall 2 of the gas drainage pipe 4. The first one-way valve chamber 5 is a cylinder with both ends closed, and its inner diameter is larger than the inner diameter of the gas drainage pipe 4. The first one-way valve chamber 5 divides the gas drainage pipe 4 into an inner gas drainage pipe 4-1 and an outer gas drainage pipe 4-2. The inner end of the first one-way valve chamber 5 is communicated with the outer end of the inner gas drainage pipe 4-1, and the inner end of the outer gas drainage pipe 4-2 is placed in the first one-way valve chamber 5 and a first one-way valve 6 is installed.

[0028] The first one-way valve 6 mainly consists of a one-way valve disc 6-1, a hinge seat 6-2, a pin shaft 6-3, a protruding part 6-4 and a ventilation hole 6-5. The one-way valve disc 6-1 blocks the inner pipe orifice of the outer gas drainage pipe 4-2. The upper end of the one-way valve disc 6-1 is hinged to the hinge seat 6-2 through the pin shaft 6-3, and the hinge seat 6-2 is welded to the upper circumferential surface of the outer gas drainage pipe 4-2. A protruding part 6-4 is arranged on the outer plate surface of the one-way valve disc 6-1, a ventilation hole 6-5 penetrating the one-way valve plate 6-1 is opened in the protruding part 6-4, the ventilation hole 6-5 is wedge-shaped, a pressure relief plug 6-6 is installed in the ventilation hole 6-5, a limit pin 6-7 is arranged on the inner side of the one-way valve disc 6-1, the limit pin 6-7 is T-shaped, it is horizontally arranged, and the outer end of its horizontal part is fixedly connected to the inner end surface of the pressure relief plug 6-6.

[0029] A first U-shaped water tank 9 is arranged below the first one-way valve chamber 5. The first U-shaped water tank 9 is composed of a connected closed pipe groove 9-1, a horizontal pipe groove 9-2 and an open pipe groove 9-3, and a floating ball 9-4 floats in the open pipe groove 9-3. The closed pipe groove 9-1 of the first U-shaped water tank 9 is communicated with the outer end of the observation pipe 8 through a connecting pipe 10. The bottom of the floating ball 9-4 is bolted to one end of a first rope 11. The other end of the first rope 11 sequentially bypasses a lower fixed pulley 9-5 at the bottom of the open pipe groove 9-3 and an upper fixed pulley 5-1 in the first one-way valve chamber 5 and is connected to the one-way valve disc 6-1 or the pressure relief plug 6-6. The upper fixed pulley 5-1 is located obliquely above the first one-way valve 6 and is installed on the inner cylinder wall of the first one-way valve chamber 5. A sealing ring is installed between the first rope 11 and the cylinder wall of the first one-way valve chamber 5.

[0030] A second one-way valve chamber 12 is installed on the nitrogen injection pipe 7 outside the isolation wall 2. The second one-way valve chamber 12 has the same structure as the first one-way valve chamber 5. The second one-way valve chamber 12 divides the nitrogen injection pipe 7 into an inner nitrogen injection pipe 7-1 and an outer nitrogen injection pipe 7-2. The outer end of the inner nitrogen injection pipe 7-1 extends into the second one-way valve chamber 12 and a second one-way valve 13 is installed. The structure of the second one-way valve 13 is the same as that of the first one-way valve 6. The inner end of the outer nitrogen injection pipe 7-2 is communicated with the outer end of the second one-way valve chamber 12.

[0031] A second U-shaped water tank 14 is installed below the second one-way valve chamber 12. The structure of the second U-shaped water tank 14 is the same as that of the first U-shaped water tank 9. The closed pipe groove 9-2 of the second U-shaped water tank 14 is communicated with the outer end of the observation pipe 8 through a connecting pipe 10. The floating ball 9-4 of the open pipe groove 9-3 of the second U-shaped water tank 14 is bolted to the lower end of the second rope 15. The upper end of the second rope 15 passes through the cylinder wall of the second one-way valve chamber 12 and bypasses the upper fixed pulley 5-1 inside it and is connected to the one-way valve piece 6-1 or the pressure relief plug 6-6 of the second one-way valve 13.

[0032] The working process of this embodiment is as follows: When the mine negative pressure decreases ( Figure 1 、 Figure 2 as shown), the gob 1 leaks air outwards. The positive pressure causes the liquid level of the open pipe groove 9-3 on the left side of the first U-shaped water tank 9 to rise. The floating ball 9-4 rises. The first rope 11 pulls the first one-way valve 6 of the outer drainage pipe 4-1. The first one-way valve 6 opens, connecting the drainage pipe 4, and extracting the gas in the gob 1 to prevent the gas in the gob 1 from overflowing. At this time, under the action of the positive pressure, the water surface of the closed pipe groove 9-1 on the left side of the second U-shaped water tank 14 rises, driving the floating ball 9-4 to rise. The second rope 15 is relaxed, causing the second one-way valve 13 to close and closing the nitrogen injection pipe 7.

[0033] When the mine negative pressure increases ( Figure 3 、 Figure 4 as shown), the gob 1 leaks air inwards. The negative pressure causes the liquid level of the open pipe groove 9-3 on the left side of the first U-shaped water tank 9 to decrease. The floating ball 9-4 descends. The first rope 11 becomes loose. The first one-way valve 6 closes, closing the drainage pipe 4. At this time, under the action of the negative pressure, the water surface of the open pipe groove 9-3 on the left side of the second U-shaped water tank 14 descends, driving the floating ball 9-4 to descend. The floating ball 9-4 drives the second rope 15 to open the second one-way valve 13, conducting the nitrogen injection pipe 7 to inject nitrogen, balancing the pressure difference inside and outside the airtight, and preventing air from entering the airtight under the action of the negative pressure to inert the air inside the airtight.

[0034] When the first rope 11 and the second rope 15 of the present invention are connected to the pressure relief plug 6-6, the ventilation hole 6-5 opens while the one-way valve piece 6-1 opens, increasing the flow area and the gas flow rate.

[0035] The above are only the preferred and feasible embodiments of the present invention, and thus do not limit the scope of the rights of the present invention. Any equivalent structural changes made by using the content of the specification and drawings of the present invention are included within the scope of the rights of the present invention.

Claims

1. An automatic control device for gas drainage and nitrogen injection pressure equalization in the gob area underground in a coal mine. There is a partition wall between the roadway and the gob area. The inner ends of the gas drainage pipe and the nitrogen injection pipe respectively pass through the partition wall and communicate with the gob area. An observation hole is opened in the partition wall. The characteristics are as follows: The first check valve and the second check valve are respectively installed on the gas drainage pipe and the nitrogen injection pipe. The observation pipe communicates with the observation hole. The outer end of the observation pipe is respectively communicated with the sealed pipe grooves of the first U-shaped water tank and the second U-shaped water tank through a connecting pipe. The first floating ball and the second floating ball are respectively arranged in the open pipe grooves of the first U-shaped water tank and the second U-shaped water tank. The first floating ball and the second floating ball respectively control the opening and closing of the first check valve and the second check valve through the first rope and the second rope. The first U-shaped water tank and the second U-shaped water tank are respectively located below the first check valve and the second check valve.

2. The gas drainage and nitrogen injection pressure equalization automatic control device for gob areas in underground coal mines according to claim 1, characterized in that: The first check valve chamber is installed on the gas drainage pipe. The gas drainage pipe includes an inner gas drainage pipe and an outer gas drainage pipe. The inner end of the first check valve chamber communicates with the outer end of the inner gas drainage pipe. The inner end of the outer gas drainage pipe is placed in the first check valve chamber and the first check valve is installed.

3. The gas drainage and nitrogen injection pressure equalization automatic control device in the goaf of underground coal mines according to claim 2, wherein: The first check valve includes a check valve disc, a hinge seat and a pin shaft. The check valve disc plugs the inner pipe orifice of the outer gas drainage pipe. The upper end of the check valve disc is hinged to the hinge seat through the pin shaft. The hinge seat is fixedly connected to the upper circumferential surface of the outer gas drainage pipe. The outer plate surface of the check valve disc is bolted to one end of the first rope. The other end of the first rope successively bypasses the upper fixed pulley in the first check valve chamber and the lower fixed pulley at the bottom of the first U-shaped water tank and is connected to the bottom of the floating ball.

4. The gas drainage and nitrogen injection pressure equalization automatic control device for goaf in underground coal mines according to claim 1, characterized in that: The second check valve chamber is installed on the nitrogen injection pipe. The nitrogen injection pipe includes an inner nitrogen injection pipe and an outer nitrogen injection pipe. The outer end of the inner nitrogen injection pipe extends into the second check valve chamber and the second check valve is installed. The inner end of the outer nitrogen injection pipe communicates with the outer end of the second check valve chamber.

5. The gas drainage and nitrogen injection pressure equalization automatic control device for gob areas in underground coal mines according to claim 4, characterized in that: The second check valve is installed at the outer pipe orifice of the inner nitrogen injection pipe. The check valve disc of the second check valve is bolted to the second rope. The second rope bypasses the upper fixed pulley in the second check valve chamber and is connected to the upper part of the second floating ball.

6. The gas drainage and nitrogen injection pressure equalization automatic control device for gob areas in underground coal mines according to claim 3, characterized in that: The check valve disc of the first check valve is provided with a wedge-shaped ventilation hole, and a pressure relief plug is arranged in the wedge-shaped ventilation hole.

7. The automatic control device for gas drainage and nitrogen injection for pressure equalization in the gob area of underground coal mines according to claim 1, characterized in that: The observation pipe communicates with a U-shaped water column gauge.

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