Goaf gas extraction branch mouth on-demand closing device and method

Abstract

The application discloses a goaf gas extraction branch pipe on-demand closing device and method. A gas bag is adhered in the extraction branch pipe, the gas bag is connected with a gas charging pipeline, when the gas concentration in the extraction main pipe is less than a predetermined value, a gas concentration sensor connected outside the extraction main pipe feeds back to a control unit through a signal line, the control unit opens a pneumatic valve, a nitrogen cylinder inflates the gas bag, the gas bag expands, and the closing of the gas extraction branch pipe is realized. After the closing, if the gas concentration in the extraction main pipe is still lower than the predetermined value, the above operation is continuously automatically executed until the gas concentration in the extraction main pipe is greater than or equal to the predetermined value. The application can realize the goaf gas extraction branch pipe on-demand closing, improve the goaf gas extraction effect, reduce the possibility of gas over-limit or gas disaster occurrence in the upper corner, reduce the energy consumption of the gas extraction pump, and promote the development of gas resources.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal mine safety, and particularly relates to a goaf gas extraction branch opening on-demand closing device and method. BACKGROUND

[0002] Coal resources are one of important energy resources in China. In the process of coal mining, due to the limitation of coal mining technology and ground protection facilities, some coal bodies are left. With the advance of the coal mining face, the coal seam roof gradually collapses, and the left coal is buried in the goaf. The left coal in the goaf has gas desorption effect. In addition, the gas near the layer will also flow to the goaf after the coal seam pressure relief. The goaf gas will flow out to the upper corner under the action of air flow, which is particularly prone to cause gas overrun or gas disaster accidents in the upper corner. Therefore, avoiding the accumulation of gas in the upper corner in the process of coal mining can effectively reduce the possibility of gas disaster.

[0003] Goaf gas extraction is an effective technical measure for goaf gas control. Goaf gas extraction generally uses the technology of goaf buried pipe. The goaf gas is extracted by arranging a gas extraction main pipe in the goaf and setting branch openings on the gas extraction main pipe. Research shows that, with the advance of the coal mining face, the farther the goaf is from the coal mining face, the lower the gas concentration is. Therefore, for the goaf far from the coal mining face, if the gas extraction is always carried out, on the one hand, the along-the-way loss of negative pressure will be greatly increased, and on the other hand, the gas extraction efficiency of the goaf close to the coal mining face will also be reduced, ultimately resulting in low extraction efficiency of the goaf gas extraction main pipe. Therefore, a goaf gas extraction branch opening on-demand closing device and method are needed. SUMMARY

[0004] The purpose of the present application is to provide a goaf gas extraction branch opening on-demand closing device and method which can close the gas extraction branch opening on demand. By adhering an air bag in the extraction branch pipe, the air bag is connected with a gas charging pipeline. When the gas concentration in the extraction main pipe is less than a predetermined value, the gas concentration sensor connected outside the extraction main pipe feeds back to the control unit through the signal line, the control unit opens the pneumatic valve, the gas charging pipeline inflates the air bag, and the air bag expands to realize the closing of the gas extraction branch opening. After the closing, if the gas concentration in the gas extraction main pipe is still lower than the predetermined value, the above operation is continuously automatically executed until the gas concentration in the gas extraction main pipe is greater than or equal to the predetermined value.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] The goaf gas extraction branch opening on-demand closing device comprises a closing unit, an inflation unit, a first extraction branch pipe, a second extraction branch pipe, an extraction main pipe and a control unit, the first extraction branch pipe and the second extraction branch pipe are both provided with the closing unit of the same structure, the closing unit comprises an air bag, a first filter screen and a second filter screen, the air bag is arranged on the inner wall of the extraction branch pipe, the first filter screen is arranged above the air bag, and the second filter screen is arranged below the air bag;

[0007] The inflation unit comprises a nitrogen cylinder, a pressure regulating valve, a first pressure sensor, a second pressure sensor, a first three-way joint, a second three-way joint and a third three-way joint, the nitrogen cylinder is connected with the pressure regulating valve through an inflation pipeline, the pressure regulating valve is connected with the right end of the first three-way joint through an inflation pipeline, the upper end of the first three-way joint is connected with the right end of the second three-way joint through an inflation pipeline, the left end of the first three-way joint is connected with the right end of the third three-way joint through an inflation pipeline, the lower end of the second three-way joint is provided with the first pressure sensor, the first pressure sensor is connected with the control unit through a signal line, the left end of the second three-way joint is connected with a first pneumatic valve through an inflation pipeline, the first pneumatic valve is connected with the air bag of the closing unit in the first extraction branch pipe through an inflation pipeline, the upper end of the third three-way joint is provided with the second pressure sensor, the second pressure sensor is connected with the control unit through a signal line, the left end of the third three-way joint is connected with a second pneumatic valve through an inflation pipeline, and the second pneumatic valve is connected with the air bag of the closing unit in the second extraction branch pipe through an inflation pipeline;

[0008] The control unit comprises a PLC controller and a plurality of methane concentration sensors, the methane concentration sensors are arranged on the outer wall of the extraction main pipe, and the methane concentration sensors are connected with the PLC controller through a signal line.

[0009] The extraction main pipe is connected with an extraction pump.

[0010] The extraction main pipe comprises a plurality of gas extraction pipes, and adjacent gas extraction pipes are connected through flanges.

[0011] The goaf gas extraction branch opening on-demand closing method is implemented based on the goaf gas extraction branch opening on-demand closing device, and comprises the following steps:

[0012] (1) the extraction pump is started to perform extraction work, the air bags of the closing units are kept in an uninflated state, and the minimum predetermined value of the gas concentration in the extraction main pipe is set through the control unit;

[0013] (2) as the extraction work is performed, when the methane concentration sensor detects that the gas concentration in the extraction main pipe is less than the minimum predetermined value, the control unit sends an instruction to the first pressure sensor through a signal line, the first pressure sensor controls the first pneumatic valve to be opened, the nitrogen cylinder inflates the air bag in the first extraction branch pipe through an inflation pipeline, and the air bag is inflated until the first extraction branch pipe is completely blocked;

[0014] (3) with the extraction work, coal mining face forward, when the methane concentration sensor again monitoring extraction main pipe gas concentration is less than the minimum predetermined value, the control unit through the signal line to the second sensor issued instructions, the second sensor control second pneumatic valve open, nitrogen cylinder through the inflation pipe to the second extraction branch pipe gas bag inflation, until the gas bag completely blocked the second extraction branch pipe.

[0015] With the coal mining face forward, the area of goaf gradually increased, need to set more extraction branch pipe in goaf, each extraction branch pipe is provided with a closing unit, each closing unit is connected with nitrogen cylinder through inflation pipe and pneumatic valve, if the methane concentration sensor again monitoring gas concentration is less than the minimum predetermined value, the control unit through the gas bag inflation forward one by one to block the extraction branch pipe, until the end of coal mining.

[0016] The present application has outstanding substantial features and significant progress compared with the prior art, specifically, the present application by adhering to the extraction branch pipe gas bag, gas bag and inflation pipe connection, when the extraction main pipe gas concentration is less than the predetermined value, the extraction main pipe connected gas concentration sensor feedback to the control unit through the signal line, the control unit will open the pneumatic valve, inflation pipe gas bag inflation, gas bag inflation to realize the closing of the gas extraction branch. After closing, the gas concentration in the gas extraction main pipe is still lower than the predetermined value, then continue to automatically execute the above operation, until the gas concentration in the gas extraction main pipe is greater than or equal to the predetermined value.

[0017] In summary, the present application can realize the goaf gas extraction branch according to the need of closing, improve the goaf gas extraction effect, reduce the possibility of gas over limit or gas disaster, reduce the energy consumption of gas extraction pump, promote the development of gas resources. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the structure diagram of the present application according to the need of closing device.

[0019] Figure 2 is Figure 1 the enlarged view of A part in figure

[0020] Figure 3 is Figure 1 the enlarged view of B part in figure DETAILED DESCRIPTION

[0021] The embodiments of the present application are further illustrated below in conjunction with the drawings.

[0022] Example one

[0023] As Figures 1-3As shown, the goaf gas extraction branch hole on-demand closing device includes a closing unit, an inflation unit, a first extraction branch pipe 2, a second extraction branch pipe 3, an extraction main pipe 1 and a control unit, the first extraction branch pipe 2 and the second extraction branch pipe 3 are both provided with the closing unit of the same structure, the closing unit includes an air bag 4, a first filter screen 5 and a second filter screen 6, the air bag 4 is arranged on the inner wall of the extraction branch pipe, the first filter screen 5 is arranged above the air bag 4, and the second filter screen 6 is arranged below the air bag 4;

[0024] The inflation unit includes a nitrogen cylinder 7, a pressure regulating valve 11, a first pressure sensor 12, a second pressure sensor 13, a first three-way joint 8, a second three-way joint 9 and a third three-way joint 10, the nitrogen cylinder 7 is connected with the pressure regulating valve 11 through an inflation pipeline, the pressure regulating valve 11 is connected with the right end of the first three-way joint 8 through an inflation pipeline, and the upper end of the first three-way joint 8 is connected with the right end of the second three-way joint 9 through an inflation pipeline. The left end of the first three-way joint 8 is connected with the right end of the third three-way joint 10 through an inflation pipeline, the lower end of the second three-way joint 9 is provided with the first pressure sensor 12, the first pressure sensor 12 is connected with the control unit through a signal line, the left end of the second three-way joint 9 is connected with a first pneumatic valve 14 through an inflation pipeline, the first pneumatic valve 14 is connected with the air bag 4 of the closing unit in the first extraction branch pipe 2 through an inflation pipeline, the upper end of the third three-way joint 10 is provided with the second pressure sensor 13, the second pressure sensor 13 is connected with the control unit through a signal line, the left end of the third three-way joint 10 is connected with a second pneumatic valve 15 through an inflation pipeline, and the second pneumatic valve 15 is connected with the air bag 4 of the closing unit in the second extraction branch pipe 3 through an inflation pipeline;

[0025] The control unit includes a PLC controller 24 and a plurality of methane concentration sensors 16, the methane concentration sensors 16 are arranged on the outer wall of the extraction main pipe 1, and the methane concentration sensors 16 are connected with the PLC controller 24 through signal lines. The extraction main pipe 1 is connected with an extraction pump 23. The extraction main pipe 1 includes a plurality of gas extraction pipes 17, and adjacent gas extraction pipes 17 are connected through flanges 18. As a coal mining working face 19 advances in the direction of an arrow 20, the coal seam roof gradually collapses, and residual coal is buried into a goaf 21, gas desorption effect occurs in the residual coal in the goaf 21, in addition, gas near the layer also flows to the goaf 21 after the coal seam is depressurized, and the gas in the goaf 21 flows to an upper corner 22 under the action of air flow, which particularly easily leads to gas overrun or gas disaster accidents in the upper corner 22, therefore, it is necessary to extract the gas in the goaf 21. However, as the length of the goaf 21 gradually extends in the direction of the arrow 20, more and more extraction branch pipes are buried into the goaf 21, as the extraction time increases, the gas concentration and flow of the extraction branch pipes far from the coal mining working face 19 gradually decrease, which affects the gas extraction effect of the extraction main pipe 1, and also greatly wastes manpower, material resources and financial resources.

[0026] Example two

[0027] The goaf gas extraction branch opening on-demand closing method is implemented based on the goaf gas extraction branch opening on-demand closing device of example one, and includes the following steps:

[0028] (1) Turn on the extraction pump 23 to perform extraction work, keep the air bags 4 of each closing unit in the un-inflated state, set the minimum predetermined value of the gas concentration in the extraction main pipe 1 through the control unit, and the minimum predetermined value is set by the engineering and technical personnel;

[0029] (2) As the extraction work proceeds, when the methane concentration sensor 16 detects that the gas concentration in the extraction main pipe 1 is less than the minimum predetermined value, the control unit issues an instruction to the first pressure sensor 12 through the signal line, the first pressure sensor 12 controls the first pneumatic valve 14 to open, the nitrogen cylinder 7 inflates the air bag 4 in the first extraction branch pipe 2 through the inflation pipeline, and the air bag 4 expands completely to block the first extraction branch pipe 2;

[0030] (3) As the extraction work proceeds, the coal mining face 19 advances forward, and when the methane concentration sensor 16 detects again that the gas concentration in the extraction main pipe 1 is less than the minimum predetermined value, the control unit issues an instruction to the second sensor through the signal line, the second sensor controls the second pneumatic valve 15 to open, the nitrogen cylinder 7 inflates the air bag 4 in the second extraction branch pipe 3 through the inflation pipeline, and the air bag 4 expands completely to block the second extraction branch pipe 3.

[0031] With the continuous advance of the coal mining face 19, the area of the goaf 21 gradually increases, more extraction branch pipes need to be arranged in the goaf 21, each of the extraction branch pipes is provided with a closing unit, each of the closing units is connected with the nitrogen cylinder 7 through the inflation pipe line and the pneumatic valve, if the methane concentration sensor 16 monitors again that the gas concentration is less than the minimum predetermined value, the control unit blocks the extraction branch pipes one by one by inflating the air bag 4 until the coal mining is finished. When the number of the extraction branch pipes is n, the first three-way joint 8 is the first (n+1) -way joint, the first (n+1) -way joint is connected with n pipe lines, each of the pipe lines is connected with a three-way joint, the upper port or the lower port of the three-way joint is connected with the pressure sensor, the pressure sensor is connected with the control unit through the signal line, the left port of the three-way joint is connected with the pneumatic valve, and the pneumatic valve is connected with the closing unit through the pipe line. With the advance of the coal mining face 19 in the direction of the arrow 20, the hydraulic support also gradually moves in the direction of the arrow 20, and the next extraction branch pipe is also gradually buried in the goaf 21, when the gas concentration in the extraction main pipe 1 is less than the predetermined value (the predetermined value is determined by the engineering and technical personnel), the above steps are repeated until the coal mining is finished. According to the application, the air bag 4 is adhered in the extraction branch pipe, the air bag 4 is connected with the inflation pipe line, when the gas concentration in the extraction main pipe 1 is less than the predetermined value, the gas concentration sensor connected outside the extraction main pipe 1 feeds back to the control unit through the signal line, the control unit opens the pneumatic valve, the inflation pipe line inflates the air bag 4, and the air bag 4 expands to realize the closing of the gas extraction branch. After the closing, if the gas concentration in the gas extraction main pipe 1 is still lower than the predetermined value, the above operation is continuously executed automatically until the gas concentration in the gas extraction main pipe 1 is greater than or equal to the predetermined value. When the extraction branch pipe is closed, the gas extraction branch in the gas extraction main pipe 1 in the goaf 21 is closed one by one from far to near, so that the gas concentration in the gas extraction main pipe 1 is greater than or equal to the predetermined value;

[0032] In conclusion, the application can realize the on-demand closing of the goaf gas extraction branch, improve the goaf gas extraction effect, reduce the possibility of gas overrun or gas disaster in the upper corner 22, reduce the energy consumption of the gas extraction pump 23, and promote the development of gas resources.

[0033] The above examples are only used to illustrate but not to limit the technical solutions of the application, although the application is described in detail with reference to the above examples, those skilled in the art should understand that the application can still be modified or replaced equivalently without departing from the spirit and scope of the application, any modification or partial replacement should be covered in the claim scope of the application.

Claims

1. A method for closing goaf gas extraction branch according to demand, based on a goaf gas extraction branch closing device according to demand, characterized in that: The gob gas extraction branch port on-demand closing device comprises a closing unit, an inflation unit, a first extraction branch pipe, a second extraction branch pipe, an extraction main pipe and a control unit, the first extraction branch pipe and the second extraction branch pipe are both provided with the closing unit of the same structure, the closing unit comprises an air bag, a first filter screen and a second filter screen, the air bag is arranged on the inner wall of the extraction branch pipe, the first filter screen is arranged above the air bag, and the second filter screen is arranged below the air bag; The inflation unit comprises a nitrogen cylinder, a pressure regulating valve, a first pressure sensor, a second pressure sensor, a first three-way joint, a second three-way joint and a third three-way joint, the nitrogen cylinder is connected with the pressure regulating valve through an inflation pipeline, the pressure regulating valve is connected with the right end of the upper end of the first three-way joint through the inflation pipeline, the right end of the upper end of the first three-way joint is connected with the right end of the second three-way joint through the inflation pipeline, the left end of the first three-way joint is connected with the right end of the third three-way joint through the inflation pipeline, the lower end of the second three-way joint is provided with the first pressure sensor, the first pressure sensor is connected with the control unit through a signal line, the left end of the second three-way joint is connected with the first pneumatic valve through the inflation pipeline, the first pneumatic valve is connected with the air bag of the closing unit in the first extraction branch pipe through the inflation pipeline, the upper end of the third three-way joint is provided with the second pressure sensor, the second pressure sensor is connected with the control unit through a signal line, the left end of the third three-way joint is connected with the second pneumatic valve through the inflation pipeline, and the second pneumatic valve is connected with the air bag of the closing unit in the second extraction branch pipe through the inflation pipeline; The control unit comprises a PLC controller and a plurality of methane concentration sensors, the methane concentration sensors are arranged on the outer wall of the extraction main pipe, and the methane concentration sensors are connected with the PLC controller through signal lines; The extraction main pipe is connected with an extraction pump. The gob gas extraction branch port on-demand closing method comprises the following steps: (1) the extraction pump is started to perform the extraction work, the air bags of the closing units are kept in the un-inflated state, and the minimum predetermined value of the gas concentration in the extraction main pipe is set through the control unit; (2) as the extraction work is performed, when the methane concentration sensor monitors that the gas concentration in the extraction main pipe is less than the minimum predetermined value, the control unit sends an instruction to the first pressure sensor through a signal line, the first pressure sensor controls the first pneumatic valve to be opened, the nitrogen cylinder inflates the air bag in the first extraction branch pipe through the inflation pipeline, and the air bag is inflated until the first extraction branch pipe is completely blocked; (3) as the extraction work is performed, the coal mining face is pushed forward, when the methane concentration sensor monitors again that the gas concentration in the extraction main pipe is less than the minimum predetermined value, the control unit sends an instruction to the second sensor through a signal line, the second sensor controls the second pneumatic valve to be opened, the nitrogen cylinder inflates the air bag in the second extraction branch pipe through the inflation pipeline, and the air bag is inflated until the second extraction branch pipe is completely blocked.

2. The gob gas extraction borehole on-demand closure method of claim 1, wherein: The extraction main pipe comprises a plurality of gas extraction pipes, and adjacent gas extraction pipes are connected through flanges.

3. The gob gas extraction borehole on-demand closure method of claim 1, wherein: With the coal mining face continuously advancing, the area of the goaf gradually increases, more extraction branch pipes need to be set in the goaf, each extraction branch pipe is provided with a closing unit, each closing unit is connected with a nitrogen cylinder through an inflation pipe and a pneumatic valve, if the methane concentration sensor again monitors that the gas concentration is less than the minimum predetermined value, the control unit blocks the extraction branch pipes one by one by inflating the air bag until the coal mining is completed.

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