Method for testing air leakage pressure difference between goaf and working face of coal mine

Abstract

The invention discloses a coal mine goaf and stope face air leakage pressure difference testing method, and relates to the field of coal mine safety. Hosepipes are embedded in an air inlet way and an air return way of the stope face in advance, and the pre-embedded hosepipes can continuously go deep into the goaf along with advancing of the stope face; one end of the outer side of the hose embedded in the goaf is connected with an inclined differential pressure gauge; a leather dragging pipe is arranged on the coal mining stope face; the pressure difference between the whole stope face and the goaf is obtained by changing the position of the pitot tube on the stope face; through multiple times of measurement, the pressure difference change rule of the whole coal mining stope face in different time periods and different positions in the goaf can be obtained. The hose is embedded in the goaf, the pitot tube is arranged on the stope face, and the inclined differential pressure gauge is connected, so that the air leakage pressure difference between the coal mine goaf and the stope face can be simply, accurately and quickly measured.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mine safety, and more specifically, to a method for testing the air leakage pressure difference between a goaf and a coal mining face in a coal mine. Background Art

[0002] There are a large number of toxic and harmful gases in the goaf of a coal mine, such as gas, carbon monoxide, hydrogen sulfide, etc. Under the action of ventilation negative pressure, they will flow from the goaf to the coal mining face, causing problems such as over-limit of gas and carbon monoxide in the coal mining face and a decrease in oxygen concentration. The air leakage pressure difference between the goaf and the coal mining face is the main factor causing the toxic and harmful gases in the goaf to flow to the coal mining face. Accurately mastering this parameter is of great significance for preventing air leakage from the goaf to the coal mining face. The complex environment in the goaf, such as water, high temperature generated by coal oxidation, a large number of toxic and harmful gases, and roof caving, makes it difficult for the buried gas pressure sensors to work well in such an extreme environment. At the same time, this air leakage pressure difference is usually only dozens to hundreds of pascals, and the accuracy of existing sensors is difficult to meet the requirements, unable to accurately measure the air leakage pressure difference between the goaf and the coal mining face. At the same time, the cost of the sensors is relatively high.

[0003] Therefore, how to provide a simple, accurate, fast, and low-cost method for testing the air leakage pressure difference between a goaf and a coal mining face in a coal mine is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the present invention provides a method for testing the air leakage pressure difference between a goaf and a coal mining face in a coal mine, aiming to solve the problems in the above background art and realizing obtaining the air leakage pressure difference between the goaf and the coal mining face through a simple, accurate, fast, and low-cost method.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for testing the air leakage pressure difference between a goaf and a coal mining face in a coal mine includes the following steps:

[0007] Step 1: Buried hoses in advance in the intake airway and return airway of the coal mining face. As the coal mining face advances, the pre-buried hoses will continuously penetrate into the goaf;

[0008] Step 2: Connect an inclined differential pressure gauge to one end of the outer side of the hose buried in the goaf;

[0009] Step 3: Set up a pitot tube in the coal mining face of coal mining and connect the pitot tube to the other end of the inclined differential pressure gauge through a hose, then the pressure difference between the coal mining face and the goaf can be measured;

[0010] Step 4: By changing the position of the pitot tube in the coal mining face and measuring at different time periods, the pressure difference between the entire coal mining face and the goaf is obtained.

[0011] Step 5: As the coal mining face advances continuously, the length of the hose left in the goaf will continue to increase. Through multiple measurements, the variation law of the pressure difference between different positions in the goaf at different time periods of the entire coal mining face can be obtained.

[0012] Further, a steel pipe is buried outside the hose to protect the hose.

[0013] Further, in Step 4, by changing the position of the pitot tube in the coal mining face and measuring at different time periods, the pressure difference between different time periods of the entire coal mining face and the goaf is obtained.

[0014] Further, in Step 5, as the coal mining face advances continuously, through multiple measurements, the variation law of the pressure difference between different positions in the goaf at different time periods of the entire coal mining face is obtained.

[0015] Further, the differential pressure gauge is an inclined differential pressure gauge.

[0016] Further, the hose is a rubber hose.

[0017] Through the above technical solutions, compared with the prior art, the present invention discloses a method for testing the air leakage pressure difference between the goaf and the coal mining face in a coal mine. By burying a hose in the goaf, setting a pitot tube in the coal mining face, and connecting an inclined differential pressure gauge, it is possible to simply, accurately, and quickly measure the air leakage pressure difference between the goaf and the coal mining face in a coal mine, obtain the variation law of the pressure difference between different time periods of the coal mining face and the goaf during the advancement of the coal mining face, which helps workers to judge the key time periods of the emission of toxic and harmful gases in the goaf, take preventive measures in advance, and thus achieve the technical effect of protecting the constructors, and can also provide strong support for the prevention and control of air leakage in the goaf. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0019] Figure 1 It is the overall structure view provided by the present invention;

[0020] Figure 2Evolution law diagram of the pressure difference between the first gob area and the upper corner of the coal mining face provided by the present invention;

[0021] Figure 3 Evolution law diagram of the pressure difference between the second gob area and the upper corner of the coal mining face provided by the present invention;

[0022] Figure 4 Evolution law diagram of the pressure difference between the third gob area and the upper corner of the coal mining face provided by the present invention;

[0023] Figure 5 Evolution law diagram of the pressure difference between the fourth gob area and the upper corner of the coal mining face provided by the present invention;

[0024] Figure 6 Evolution law diagram of the pressure difference between the fifth gob area and the upper corner of the coal mining face provided by the present invention;

[0025] Figure 7 Evolution law diagram of the pressure difference between the sixth gob area and the upper corner of the coal mining face provided by the present invention;

[0026] Figure 8 Evolution law diagram of the pressure difference between the seventh gob area and the upper corner of the coal mining face provided by the present invention;

[0027] Figure 9 Evolution law diagram of the pressure difference between the eighth gob area and the upper corner of the coal mining face provided by the present invention.

[0028] Among them, 1 is the intake airway; 2 is the return airway; 3 is the coal mining face; 4 is the gob area; 5 is the differential pressure gauge; 6 is the pitot tube; 7 is the steel pipe; 8 is the hose. Specific implementation manner

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] See Figures 1-9 , the embodiments of the present invention disclose a method for testing the air leakage differential pressure between a coal mine gob area and a coal mining face, including the following steps:

[0031] Step 1: Buried hoses 8 in advance in the intake airway 1 and the return airway 2 of the coal mining face 3. As the coal mining face 3 advances, the pre-buried hoses 8 will continuously penetrate into the gob area 4;

[0032] Step 2: Connect an inclined differential pressure gauge 5 to one end of the outer side of the hose 8;

[0033] Step 3: Set up the pitot tube 6 at the coal mining face, and connect the other end of the pitot tube 6 to the inclined differential pressure gauge 5 through a hose, then the differential pressure between the coal mining face 3 and the gob 4 can be measured.

[0034] Step 4: By changing the position of the pitot tube 5 at the coal mining face 3 and measuring at different time periods, the differential pressure between the entire coal mining face 3 and the gob 4 at different time periods can be obtained.

[0035] Step 5: As the coal mining face 3 continuously advances, the length of the hose 8 remaining in the gob will continue to increase. Through multiple measurements, the variation law of the pressure difference at different positions between the entire coal mining face 3 and the gob 4 can be obtained.

[0036] Bury the steel pipe 7 outside the hose 8. The steel pipe 7 serves to protect the hose 8, and the length of the steel pipe 7 is the same as that of the hose 8.

[0037] In Step 4, the differential pressure at multiple positions of the coal mining face 3 is measured, and the differential pressure between different positions of the coal mining face 3 and the gob 4 is measured. When the pitot tube 6 is placed at the upper corner of the coal mining face 3, the reading of the differential pressure gauge 5 at this time is the air leakage pressure difference between the upper corner and the gob 4. When placed at different positions, the air leakage differential pressure between the corresponding position and the corresponding gob 4 can be measured. By measuring at different time periods, the air leakage difference between this position and the corresponding gob 4 at the corresponding time period can be measured, and then the air leakage differential pressure between different positions of the coal mining face 3 and the gob 4 at different time periods can be mastered.

[0038] The differential pressure gauge 5 is an inclined differential pressure gauge. The hose 8 is a rubber hose 8.

[0039] The reason why the low-oxygen gas and toxic and harmful gases such as carbon monoxide in the gob 4 flow towards the coal mining face 3 is that there is a certain pressure difference between the gob 4 and areas such as the upper corner of the coal mining face 3. Mastering the pressure difference between the gob 4 and the upper corner of the coal mining face 3 is a key parameter for evaluating the flow of low-oxygen gas and toxic and harmful gases such as carbon monoxide towards the coal mining face 3. The evolution law of the pressure difference between the gob 4 and the upper corner of the coal mining face 3 is as Figures 2-9 shown.

[0040] Based on the measured data, it can be concluded that within one day, the pressure difference between the gob area 4 and the upper corner shows an overall "U"-shaped variation pattern. The pressure difference is in a relatively high range during the time period from 0 to 5 o'clock. Subsequently, the pressure difference gradually decreases and reaches the peak valley value around 9 o'clock. After that, until 14 o'clock, the change in the pressure difference is not significant and it basically varies near the peak valley. After 14 o'clock, the pressure difference gradually increases again, and after about 18 o'clock, the pressure difference is again in a relatively high range, but the pressure difference in this stage is less than the high pressure difference in the stage from 0 to 5 o'clock. Based on the obtained pressure difference data for different time periods, it is possible to judge the key time periods for the emission of toxic and harmful gases in the gob area, take preventive measures in advance to ensure the safety of workers, and also provide strong support for the prevention and control of air leakage in the gob area.

[0041] In this embodiment, based on the measured pressure difference data and combined with the test data of the ground atmospheric pressure, it is also possible to analyze the connection situation between the gob area 4 and the ground. The connection situation between the gob area 4 and the ground can be divided into three cases: the gob area 4 is a completely enclosed environment, a semi-enclosed environment, and a completely open environment.

[0042] First, assume that the inside of the gob area 4 is a completely enclosed environment. The static pressure inside the gob area 4 is less affected by the outside world and can be considered to be basically a constant value. While during the ventilation process of the coal mining face 3, it can be regarded as an open environment. As the atmospheric pressure changes, its static pressure will also change accordingly. However, according to Figures 4-7 (the variation pattern of the maximum pressure difference), within the measured time period, the minimum atmospheric pressure difference is 500 Pa, and the maximum reaches 1200 Pa. In this assumed situation, the pressure difference between the upper corner and the inside of the gob area 4 should also be within the range of several hundred Pa, which would be much greater than the measured value of several tens of Pa in this time. Based on this analysis, it can be considered that the gob area 4 is not a completely enclosed environment.

[0043] Secondly, assume that the gob area 4 is a completely open environment. In this case, the static pressures inside the gob area 4 and between the gob area 4 and the coal mining face 3 will change in a timely manner as the atmospheric pressure changes. In this situation, the pressure difference between the gob area 4 and the coal mining face 3 will basically remain relatively stable as a fixed value and will not fluctuate with the change of the atmospheric pressure. At the same time, its pressure difference will also be greater than the measured value in this time. From this perspective, the gob area 4 is not a completely open environment.

[0044] Through the above analysis, it is not difficult to conclude that the gob area 4 is a semi-enclosed environment and can be preliminarily considered as an intermediate body, that is, the air pressure inside the gob area 4 is less than the atmospheric pressure but greater than the air pressure of the coal mining face 3, and the fluctuation of the atmospheric pressure is the main reason for the change in the pressure difference between the coal mining face 3 and the gob area 4.

[0045] In the present specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts among the various embodiments can be referred to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0046] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for testing the air leakage pressure difference between the goaf and the mining working face of a coal mine, characterized in that: The following steps are involved: Step 1: bury hoses in advance in the air inlet and return air channels of the mining face. As the mining face advances, the pre-buried hoses will continue to penetrate deeper into the goaf; Step 2: Connect an inclined differential pressure gauge to one end of the outer side of the hose buried in the goaf; Step 3: Set up a pitot tube at the coal mining working face, and connect the pitot tube to the other end of the inclined differential pressure gauge through a hose, so as to measure the pressure difference between the mining working face and the goaf; Step 4: By changing the position of the pitot tube on the mining face and measuring at different time periods, the pressure difference between the entire mining face and the goaf can be obtained; Step 5: As the mining face continues to advance, the length of the hose left in the goaf will continue to increase. Through multiple measurements, the change pattern of the pressure difference between the entire coal mining face and different positions in the goaf in different time periods can be obtained.

2. A method for testing the air leakage pressure difference between a coal mine goaf and a mining working face according to claim 1, characterized in that: A steel pipe is buried outside the hose to protect the hose.

3. A method for testing the air leakage pressure difference between a coal mine goaf and a mining working face according to claim 1, characterized in that: In step 4, by changing the position of the pitot tube on the mining face and performing measurements in different time periods, the pressure difference between the entire mining face and the goaf in different time periods is obtained.

4. A method for testing the air leakage pressure difference between a coal mine goaf and a mining working face according to claim 1, characterized in that: In step five, as the mining face continues to advance, multiple measurements are performed to obtain the variation pattern of the pressure difference between the entire coal mining face and different positions in the goaf in different time periods.

5. A method for testing the air leakage pressure difference between a coal mine goaf and a mining working face according to claim 1, characterized in that: The differential pressure gauge is an inclined differential pressure gauge.

6. A method for testing the air leakage pressure difference between a coal mine goaf and a mining working face according to claim 1, characterized in that: The hose is a rubber hose.

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