Equipment for accurately testing the amount of gas desorption in the underground negative pressure coring environment by inflation linkage

Abstract

The equipment for accurately testing the gas desorption amount in the underground negative pressure coring environment by inflation linkage includes a mobile frame, a coal sample filtering system, a coal sample tank, a negative pressure regulating system and an inflation system. The bottom of the mobile frame is equipped with foldable and retractable rollers. The coal sample tank, the negative pressure regulating system and the inflation system are all arranged on the mobile frame. The coal sample inlet of the coal sample filtering system is connected to the outer end of the drill pipe, the coal sample outlet of the coal sample filtering system is connected to the coal sample inlet of the coal sample tank, the coal sample outlet of the coal sample tank is connected to the negative pressure suction port of the negative pressure ejection system, the coal sample tank is connected to the negative pressure generating chamber of the negative pressure regulating system through a first gas pipeline, and the negative pressure regulating chamber of the negative pressure regulating system is connected to the inflation system through a second gas pipeline. The present invention can ensure that the coal sample completes gas desorption under a certain constant negative pressure condition, accurately tests the gas desorption amount in the negative pressure coring environment, does not require electrical control, does not contain electrical equipment, and the negative pressure value required for coal sample desorption can be precisely adjusted.

Description

Technical Field

[0001] The present invention relates to the field of coal mine safety technology, and in particular to equipment for accurately testing the amount of gas desorption in an underground negative pressure coring environment through a gas-inflating linkage. Background Art

[0002] Coal and gas outbursts are the top priority for coal mine gas prevention and control in my country. The gas content of coal seams is closely related to the identification of coal seam outburst hazards, evaluation of coal seam extraction effects, regional prediction of coal seam outburst hazards, and verification of the effectiveness of regional outburst prevention measures. Therefore, the reliability and accuracy of coal seam gas content measurement results are crucial.

[0003] The direct determination method for determining the gas content of coal seams requires the loss of gas, the desorption of gas (underground gas desorption and surface gas desorption) and the residual gas. The underground gas desorption, surface gas desorption and residual gas can all be obtained through experiments, and the loss of gas is obtained by inverting the underground gas desorption. Therefore, the accuracy of underground gas desorption is closely related to the accuracy of the inversion of the loss of gas. Negative pressure coring is a classic method for coring underground coal seams. The coal samples obtained by negative pressure coring are in a negative pressure environment in the negative pressure coring system and the coal sample tank. Operators usually desorb gas from the coal samples in the coal sample tank under atmospheric pressure to obtain the amount of gas desorption underground. However, the desorption environment of the coal samples undergoes a sudden change from negative pressure to atmospheric pressure. The amount of gas loss in the negative pressure desorption environment is inverted based on the amount of gas desorption underground under atmospheric pressure, which causes distortion of the amount of gas loss and inaccurate determination of coal seam gas content.

[0004] The graduation thesis of Zhang Hongliang, a master of Henan University of Technology, is "Study on the Gas Desorption Law of Coal in Negative Pressure Environment". The thesis discloses a set of negative pressure environment gas desorption measurement equipment. Negative pressure is a key factor affecting gas desorption, so the accuracy of the negative pressure value is very important. The device used in the thesis generates negative pressure by applying a counterweight, but the mass of the counterweight varies, and the negative pressure value cannot be continuously and accurately controlled. Inaccurate control of the negative pressure value leads to inaccurate gas desorption test, and inaccurate gas desorption test leads to inaccurate estimation of gas loss, which ultimately leads to inaccurate test of gas content in coal seams.

[0005] Chinese patent ZL 201610014944.3 discloses a coal sample gas negative pressure desorption experimental system. The system controls the negative pressure value through a human-computer interaction platform and a servo motor. However, the experimental system is established based on laboratory testing and cannot be used for field testing. It is necessary to first make the coal sample adsorb gas and then conduct a negative pressure desorption test, which has poor authenticity. The reasons are as follows: (1) When the negative pressure injection sampling is completed, the coal sample tank is in a negative pressure environment, and the device actually uses the negative pressure environment in the negative pressure control module to change the pressure in the coal sample tank from a normal pressure environment to a negative pressure environment. During the process of induced sampling or negative pressure sampling, the coal sample tank is in a negative pressure environment. Therefore, the coal sample desorption environment in the device does not conform to the process of underground induced sampling or negative pressure sampling; (2) The negative pressure control module, solenoid valve, and computer in the experimental system are all electrically controlled. When electrical equipment is used underground in coal mines, it is necessary to meet the relevant national standards and it is very inconvenient to use; (3) When the underground use location is different, it needs to be reassembled and connected to the power supply. Summary of the invention

[0006] The purpose of the present invention is to provide an inflation-linked device for accurately testing the amount of gas desorption in an underground negative pressure coring environment. The present invention can ensure that coal samples complete gas desorption under a certain constant negative pressure condition, accurately test the amount of gas desorption in a negative pressure coring environment, does not require electrical control and does not contain electrical equipment, thereby improving the safety factor of the working environment, and the negative pressure value required for coal sample desorption can be precisely adjusted.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The equipment for accurately testing the amount of gas desorption in the underground negative pressure coring environment by inflation linkage comprises a mobile frame, a coal sample filtering system, a coal sample tank, a negative pressure regulating system and an inflation system. The bottom of the mobile frame is equipped with rollers which are supported on the ground and can be folded for storage. The coal sample tank, the negative pressure regulating system and the inflation system are all arranged on the mobile frame. The coal sample inlet of the coal sample filtering system is connected to the outer end of the drill pipe, the coal sample outlet of the coal sample filtering system is connected to the coal sample inlet of the coal sample tank, the coal sample outlet of the coal sample tank is connected to the negative pressure suction port of the negative pressure injection system, the coal sample tank is connected to the negative pressure generating chamber of the negative pressure regulating system through a first gas pipeline, and the negative pressure regulating chamber of the negative pressure regulating system is connected to the inflation system through a second gas pipeline.

[0009] The coal sample filtering system includes a filter box and a large coal sample barrel. The filter box is fixedly connected to the upper side of the front side wall of the large coal sample barrel. A filter plate with a high front and a low back is arranged in the middle of the filter box. A sample outlet located above the filter plate is opened in the middle of the rear side plate of the filter box. A large coal feed port corresponding to the front and rear of the sample outlet is opened on the upper side of the front side wall of the large coal sample barrel. The lower sides of the sample outlet and the large coal feed port are flush with the rear side of the filter plate. The upper side of the left side plate of the filter box is connected to a coal sample inlet pipe located above the filter plate, and the lower side of the right side plate of the filter box is connected to a coal sample outlet pipe located below the filter plate. The other end of the coal sample inlet pipe is connected with the outer end of the drill pipe, an upper cover is installed on the top of the coal sample tank, a coal sample extraction inlet is provided on the left side of the upper cover, a coal sample extraction outlet is provided on the right side of the upper cover, and a first gas interface is provided at the top center of the upper cover, the other end of the coal sample outlet pipe is connected with the coal sample extraction inlet, and the coal sample extraction outlet is connected with the negative pressure suction port of the negative pressure injection system through a coal sample suction pipe, a first valve is provided on the coal sample outlet pipe, and a second valve is provided on the coal sample suction pipe. The mesh diameter of the filter plate is smaller than the inner diameter of the coal sample inlet pipe, and the sizes of the sample outlet and the bulk coal feed port are both larger than the inner diameter of the coal sample inlet pipe.

[0010] The negative pressure regulating system comprises a negative pressure unit cylinder, a negative pressure unit piston, a negative pressure unit guide rod, a gas-adjusting unit cylinder, a gas-adjusting unit piston and a gas-adjusting unit guide rod. The center lines of the negative pressure unit cylinder, the negative pressure unit piston, the negative pressure unit guide rod, the gas-adjusting unit cylinder, the gas-adjusting unit piston and the gas-adjusting unit guide rod coincide and are arranged vertically. The top of the negative pressure unit cylinder is open. A sealing cover is threadedly installed on the outer circumference of the upper end of the negative pressure unit cylinder. A first O-ring is embedded on the upper end edge of the negative pressure unit cylinder in tight contact with the inner top surface of the sealing cover. A second gas interface is arranged at the top center of the sealing cover. Two ends of the first gas pipeline are respectively connected to the first gas interface and the second gas interface. The first gas pipeline is provided with gaskets in sequence from the first gas interface to the second gas interface. The first precision negative pressure gauge, the third valve, the two-way valve, the fourth valve, the second precision negative pressure gauge and the first exhaust pipeline, the first exhaust pipeline is provided with a fifth valve, the negative pressure unit piston is sealingly slidably arranged in the negative pressure unit cylinder, the negative pressure generating chamber of the negative pressure regulating system is the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston, the outer circumference of the negative pressure unit piston is in sealing and sliding contact with the inner wall of the negative pressure unit cylinder, two second O-rings spaced apart up and down are fixedly embedded on the outer circumference of the negative pressure unit piston, the outer circle of the second O-ring is in sealing and sliding contact with the inner wall of the negative pressure unit cylinder, the negative pressure unit guide rod is slidably arranged in the negative pressure unit cylinder, the upper end of the negative pressure unit guide rod is threadedly fixedly connected to the bottom center of the negative pressure unit piston, and the negative pressure unit guide rod is vertically connected to the negative pressure unit cylinder. A straight-through sealing sliding connection is connected in the center of the bottom plate of the negative pressure unit cylinder, and two third O-rings spaced apart are fixedly embedded in the middle of the bottom plate of the negative pressure unit cylinder. The negative pressure unit guide rod vertically passes through the two third O-rings and is in sliding sealing contact with the inner circles of the two third O-rings. The lower side of the right side wall of the negative pressure unit cylinder is connected to the second exhaust pipeline located below the negative pressure unit piston, and a sixth valve is arranged on the second exhaust pipeline. The bottom of the gas conditioning unit cylinder is open, and a threaded blind hole with an open upper side is provided in the middle of the top of the gas conditioning unit cylinder. The lower end of the negative pressure unit cylinder is matched with a thread connection in the threaded blind hole, and the lower surface of the bottom plate of the negative pressure unit cylinder is in tight sealing contact with the bottom of the threaded blind hole, and the lower surface of the bottom plate of the negative pressure unit cylinder is in tight sealing contact with the bottom of the threaded blind hole. A fourth O-ring is fixedly embedded in the same center as above and is in tight contact with the bottom of the threaded blind hole. The middle part of the outer wall of the negative pressure unit cylinder is fixedly connected to the top center of the mobile frame. The negative pressure unit guide rod vertically penetrates and is sealed and slidably connected to the center of the top plate of the gas-conditioning unit cylinder. The lower end of the negative pressure unit guide rod extends into the gas-conditioning unit cylinder. A fifth O-ring is fixedly embedded in the middle part of the top plate of the gas-conditioning unit cylinder. The negative pressure unit guide rod vertically penetrates the fifth O-ring and is in sliding and sealing contact with the inner circle of the fifth O-ring. The gas-conditioning unit piston is sealingly and slidably arranged in the gas-conditioning unit cylinder. The negative pressure generating chamber of the negative pressure regulating system is the inner cavity of the gas-conditioning unit cylinder on the upper side of the gas-conditioning unit piston. The outer circumference of the gas-conditioning unit piston is in sealing and sliding contact with the inner wall of the gas-conditioning unit cylinder.Two sixth O-rings are fixedly mounted on the outer circumference of the gas-adjusting unit piston and spaced apart from each other. The outer circumference of the sixth O-ring is in sealing and sliding contact with the inner wall of the gas-adjusting unit cylinder. The lower end of the negative pressure unit guide rod is threadedly fixedly connected to the top center of the gas-adjusting unit piston. The gas-adjusting unit guide rod is arranged directly below the gas-adjusting unit piston. The upper end of the gas-adjusting unit guide rod is threadedly fixedly connected to the bottom center of the gas-adjusting unit piston. The lower end of the gas-adjusting unit guide rod extends out of the lower port of the gas-adjusting unit cylinder. The right side of the top plate of the gas-adjusting unit cylinder is provided with a third gas interface. A scale is vertically arranged on the upper edge of the gas-adjusting unit guide rod, and the zero scale value is located at the lower end of the gas-adjusting unit guide rod. Initially, the distance between the gas-adjusting unit piston and the inner top surface of the gas-adjusting unit cylinder is not less than the distance between the negative pressure unit piston and the inner top surface of the sealing cover. The lower side of the mobile frame is provided with an upward push device located at the front lower part of the gas-adjusting unit cylinder and pushing the gas-adjusting unit guide rod to move upward.

[0011] The pushing device includes a foot pedal, two pressure springs, an upward pushing support plate, an upward pushing guide rod, a guide cylinder, two first fixed pulleys, two second fixed pulleys and two pulling wire ropes. The foot pedal is arranged at an angle at the front lower part of the cylinder of the gas-conditioning unit with a lower front and a higher rear. The lower side of the foot pedal is hinged to the front lower part of the moving frame through a hinge seat. The two pressure springs are spaced left and right and are arranged at the rear side of the foot pedal with a higher front and a lower rear. The two ends of the two pressure springs are respectively fixedly connected to the upper side of the rear side of the foot pedal and the moving frame. The upward pushing support plate is horizontally arranged just below the guide rod of the gas-conditioning unit. The upper The upper push guide rod and the guide cylinder are both vertically arranged directly below the upper push support plate, and the upper end of the upper push guide rod is fixedly connected to the middle of the lower surface of the upper push support plate. The outer circumference of the guide cylinder is fixedly connected to the moving frame through the first bracket, and the upper push guide rod is slidably connected in the guide cylinder concentrically. A second bracket fixedly connected to the moving frame is arranged on the left and right sides of the upper push support plate, and the two first fixed pulleys are respectively rotatably connected to the tops of the two second brackets and are located on the upper left and right sides of the upper push support plate. A The two second fixed pulleys are rotatably connected to the tops of the two third brackets respectively, the height of the second fixed pulley is lower than the height of the first fixed pulley, the rotating shafts of the two first fixed pulleys and the two second fixed pulleys are horizontally arranged in the left and right directions, the two lifting steel ropes are symmetrically arranged in the left and right directions and are arranged in the front and rear directions, the front end of the lifting steel rope on the left side is fixedly connected to the left side part of the upper side edge of the foot pedal, the lifting steel rope on the left side extends backward and is successively wound around the upper side part of the second fixed pulley on the left side and the upper side part of the first fixed pulley on the left side, and the left side The lifting wire rope passes around the upper side of the first fixed pulley on the left and then extends vertically downward. The lower end of the lifting wire rope on the left is fixedly connected to the middle left part of the upper surface of the upper push support plate, and the front end of the lifting wire rope on the right is fixedly connected to the right side of the upper side edge of the foot pedal. The lifting wire rope on the right extends backward and is successively wrapped around the upper side of the second fixed pulley on the right and the upper side of the first fixed pulley on the right. The lifting wire rope on the right passes around the upper side of the first fixed pulley on the right and then extends vertically downward. The lower end of the lifting wire rope on the right is fixedly connected to the middle right part of the upper surface of the upper push support plate.

[0012] The inflation system includes a high-pressure nitrogen bottle. Both ends of the second gas pipeline are respectively connected to the outlet of the high-pressure nitrogen bottle and the third gas interface. A nitrogen pressure regulating valve, a first precision pressure gauge, a seventh valve, a second precision pressure gauge and a third exhaust pipeline are sequentially arranged on the second gas pipeline along the gas flow direction. The third exhaust pipeline is provided with an eighth valve.

[0013] The method for testing the gas desorption amount under negative pressure coring environment with precise adjustment of negative pressure by adopting the above technical solution specifically comprises the following steps:

[0014] (1) Assemble the equipment for accurately testing the desorption amount of gas in the underground negative pressure coring environment at the underground coal mining site;

[0015] (2) Exhaust the indoor air generated by the negative pressure regulating system;

[0016] (III) The coal sample is filtered by the coal sample filtration system and then drawn into the coal sample tank through the negative pressure injection system, so that the coal sample tank is filled with coal samples and is in a negative pressure environment. The negative pressure value is recorded as p 0;

[0017] (IV) Inflate the negative pressure regulating chamber of the negative pressure regulating system through the inflation system, so that the negative pressure generating chamber of the negative pressure regulating system forms the same negative pressure environment as that in the coal sample tank. The negative pressure value is recorded as p 0;

[0018] (V) Connect the coal sample tank to the negative pressure generating chamber of the negative pressure regulating system, and continuously inflate the negative pressure regulating chamber of the negative pressure regulating system through the inflation system to control the negative pressure generating chamber of the negative pressure regulating system to maintain a stable negative pressure. p Desorption under 0 conditions, the negative pressure value is calculated p 0 at different times t n0 Cumulative gas desorption Q n0 ;

[0019] (VI) Negative pressure value is p After the gas desorption test under 0 conditions is completed, the inflation system stops inflating, and the negative pressure generating chamber and the negative pressure regulating chamber of the negative pressure regulating system are connected to the outside atmosphere;

[0020] (VII) Use Origin drawing software to draw the negative pressure value p Cumulative gas desorption under 0 conditions Q n0 About time t n0 The scatter curve of

[0021] (VIII) Clean out the desorbed coal sample in the coal sample tank, repeat steps (II) to (VII), and draw new coal sample into the coal sample tank. The negative pressure value in the coal sample tank is recorded as p n , through the inflation system, the negative pressure of the negative pressure regulating system is adjusted to the indoor negative pressure value p n And keep it constant, calculate the negative pressure value p n At different times under different conditions t nn Cumulative gas desorption Qnn , and plot the negative pressure value as p n Cumulative gas desorption under the condition Q nn About time t nn The scatter curve of step (ii) is as follows: initially, the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve and the eighth valve are all in a closed state, the fifth valve, the sixth valve and the eighth valve are opened, and then the operator steps on the foot pedal to flip the foot pedal backward and downward, and the foot pedal pulls the front ends of the two lifting wire ropes downward, and then the rear ends of the two lifting wire ropes lift the upper push support plate upward, so that the upper push support plate moves upward, and then the upper push support plate pushes the gas control unit guide rod upward, and the upper push guide rod slides in the guide cylinder to play a guiding role, and the gas control unit guide rod pushes the gas control unit piston upward, and the gas control unit piston moves upward to compress the air in the gas control unit cylinder on its upper side, so that the air in the gas control unit cylinder on the upper side of the gas control unit piston is discharged through the third gas interface, the second gas pipeline and the third exhaust pipeline, and at the same time, the gas control unit piston drives the negative pressure unit guide rod to move upward, and the negative pressure unit guide rod pushes the negative pressure unit piston to move upward, and the negative pressure unit below the negative pressure unit piston The inner cavity of the cylinder becomes negative pressure, so that the outside air is sucked into the inner cavity of the negative pressure unit cylinder on the lower side of the negative pressure unit piston through the second exhaust pipe, so that the inner cavity of the negative pressure unit cylinder on the lower side of the negative pressure unit piston is balanced with the external atmospheric pressure, and the negative pressure unit piston moves upward to compress the air in the negative pressure unit cylinder on its upper side, so that the air in the negative pressure unit cylinder on the upper side of the negative pressure unit piston is discharged through the second gas interface, the first gas pipeline and the first exhaust pipe, until the negative pressure unit piston moves upward to an immovable position, that is, the upper surface of the negative pressure unit piston is in close contact with the inner top surface of the sealing cover, so that the air in the negative pressure unit cylinder on the upper side of the negative pressure unit piston can be completely discharged, and then, the foot pedal is released, and the foot pedal is flipped forward and reset under the reset action of the top pressure spring, and the upper push support plate and the upper push guide rod move downward and return to the initial position under the action of gravity, the upper push support plate is separated from the guide rod of the gas control unit, the fifth valve and the eighth valve are closed, and the scale value corresponding to the lower port of the gas control unit cylinder on the guide rod of the gas control unit is recorded at this time. h 0.

[0022] Step (three) is specifically as follows: open the first valve and the second valve, start the negative pressure injection system, the negative pressure injection system extracts the coal that has fallen off during the drilling process of the drill bit through the drill rod, and the coal blocks enter the upper side of the filter box through the coal sample inlet pipe, and the coal blocks fall onto the filter screen for filtration, the large pieces of coal roll directly downward along the filter screen in the filter box and fall into the large piece coal sample barrel through the sample outlet and the large piece coal feed port, while the small pieces of coal and coal powder pass downward through the mesh of the filter screen and fall into the lower side of the filter box and are then output through the coal sample outlet pipe, the small pieces of coal and coal powder are drawn into the coal sample tank along the coal sample outlet pipe, when the coal sample tank is full of small pieces of coal and coal powder, close the first valve, the second valve and the negative pressure injection system, and the small pieces of coal and coal powder in the coal sample tank are used as the coal sample to be tested, at this time the coal sample in the coal sample tank is in a negative pressure environment, and the negative pressure value of the first precision negative pressure gauge is recorded as p 0.

[0023] Step (four) is specifically as follows: open the fourth valve and the main valve on the top of the high-pressure nitrogen cylinder, adjust the nitrogen pressure regulating valve so that the outlet of the nitrogen pressure regulating valve produces a constant outlet pressure, open the seventh valve, and then the nitrogen in the high-pressure nitrogen cylinder is pressure-regulated by the nitrogen pressure regulating valve and filled into the cylinder of the gas-adjusting unit through the second gas pipeline, then the gas pressure in the cylinder of the gas-adjusting unit increases, and the gas in the cylinder of the gas-adjusting unit pushes the piston of the gas-adjusting unit to move downward, and the piston of the gas-adjusting unit drives the guide rod of the negative pressure unit to move downward, and the guide rod of the negative pressure unit drives the piston of the negative pressure unit to move downward, then the piston of the negative pressure unit moves downward to compress the air in the cylinder of the negative pressure unit below it, so that the air in the cylinder of the negative pressure unit below the piston of the negative pressure unit is discharged through the second exhaust pipeline, and at the same time, a negative pressure environment is formed in the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston, observe the negative pressure value of the second precision negative pressure gauge, and fine-tune the nitrogen pressure regulating valve until the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston produces the same negative pressure environment as that in the coal sample tank, that is, the negative pressure value of the second precision negative pressure gauge is adjusted to p 0, and record the pressure value of the second precision pressure gauge at this time P 0, then stop fine-tuning the nitrogen pressure regulating valve, and the outlet pressure of the nitrogen pressure regulating valve is also P 0 and constant, that is, the pressure value of the first precision pressure gauge is also P 0, at this time the negative pressure in the coal sample tank is the same as the negative pressure in the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston, the negative pressure unit piston and the gas conditioning unit piston are balanced, and the gas conditioning unit piston and the negative pressure unit piston both stop moving.

[0024] Step (V) is as follows: Open the third valve, and the coal sample tank is connected to the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston through the first gas pipeline, and the coal sample in the coal sample tank is p0 condition, the desorbed gas will enter the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston through the first gas pipeline. Then the pressure in the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston increases, and the negative pressure decreases. The upward suction force formed by the negative pressure in the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston is smaller than the downward thrust formed by the positive pressure in the gas conditioning unit cylinder. The negative pressure unit piston and the gas conditioning unit piston lose balance. Since the outlet pressure of the nitrogen pressure regulating valve is constant at P 0, the nitrogen in the high-pressure nitrogen bottle continues to be filled into the cylinder of the gas-controlled unit, and the gas in the cylinder of the gas-controlled unit continuously pushes the piston of the gas-controlled unit to move downward. The piston of the gas-controlled unit drives the piston of the negative pressure unit to move downward together through the negative pressure unit guide rod, thereby increasing the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston, and the negative pressure can be instantly adjusted to p 0, so that the negative pressure unit piston and the gas control unit piston are always balanced. During this process, every time t , then record the scale value on the gas conditioning unit guide rod corresponding to the lower port of the gas conditioning unit cylinder h n0 (n=1, 2, 3, 4, 5, 6...), until the piston of the gas conditioning unit stops moving, it means that the coal sample in the coal sample tank is under negative pressure. p 0, the gas desorption is completed, then t n0 The scale value on the guide rod of the gas conditioning unit corresponding to the lower port of the gas conditioning unit cylinder h n0 Subtract the scale value corresponding to when the piston of the gas conditioning unit moves upward to the highest point in step (3) h 0, you can get a certain moment t n0 The cumulative distance that the piston of the gas conditioning unit drives the guide rod of the negative pressure unit to move downward, that is, at a certain moment t n0 The cumulative distance that the negative pressure unit piston moves downward is recorded as h n0 - h 0, then the negative pressure value can be calculated by the formula p 0 at different times t n0 Cumulative gas desorption Q n0 , Q n0 =π r 2 ( h n0 - h 0), r is the inner diameter of the negative pressure unit cylinder.

[0025] Step (six) is as follows: the negative pressure value is p After the gas desorption test under 0 conditions is completed, the third valve, the fourth valve, the seventh valve and the main valve on the top of the high-pressure nitrogen bottle are closed to stop the nitrogen in the high-pressure nitrogen bottle from being charged into the cylinder of the gas conditioning unit. Then, the fifth valve and the eighth valve are opened to connect the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston and the inner cavity of the gas conditioning unit cylinder to the outside atmosphere;

[0026] In step (eight), the negative pressure of the negative pressure regulating system is adjusted to a negative pressure value in the room by means of the inflation system. p n The specific implementation method of maintaining a constant pressure is the same as the operation process in step (iv): open the fourth valve and the main valve on the top of the high-pressure nitrogen cylinder, adjust the nitrogen pressure regulating valve, so that the outlet of the nitrogen pressure regulating valve produces a constant outlet pressure, open the seventh valve, and the nitrogen in the high-pressure nitrogen cylinder is regulated by the nitrogen pressure regulating valve and then filled into the cylinder of the gas-adjusting unit through the second gas pipeline. Then the gas pressure in the cylinder of the gas-adjusting unit increases, and the gas in the cylinder of the gas-adjusting unit pushes the piston of the gas-adjusting unit to move downward, and the piston of the gas-adjusting unit drives the guide rod of the negative pressure unit to move downward. The negative pressure unit guide rod drives the negative pressure unit piston to move downward, and the negative pressure unit piston moves downward to compress the air in the negative pressure unit cylinder below it, so that the air in the negative pressure unit cylinder below the negative pressure unit piston is discharged through the second exhaust pipe. At the same time, a negative pressure environment is formed in the inner cavity of the negative pressure unit cylinder above the negative pressure unit piston. The negative pressure value of the second precision negative pressure gauge is observed, and the nitrogen pressure regulating valve is fine-tuned until the inner cavity of the negative pressure unit cylinder above the negative pressure unit piston produces the same negative pressure environment as that in the coal sample tank, that is, the negative pressure value of the second precision negative pressure gauge is adjusted to p n , and record the pressure value of the second precision pressure gauge at this time P n , then stop fine-tuning the nitrogen pressure regulating valve, and the outlet pressure of the nitrogen pressure regulating valve is also P n And constant, that is, the pressure value of the first precision pressure gauge is also P n At this time, the negative pressure in the coal sample tank is the same as the negative pressure in the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston, the negative pressure unit piston and the gas conditioning unit piston are balanced, and the gas conditioning unit piston and the negative pressure unit piston both stop moving.

[0027] The present invention has outstanding substantial specificity and significant progress compared with the prior art. Specifically, the present invention has the following advantages:

[0028] (1) The experimental device of the present invention is arranged at the underground coal mining site. The negative pressure injection system can be used to obtain coal samples by negative pressure injection coring in the underground, thereby directly obtaining gas-containing coal in the underground, and forming a negative pressure in the coal sample tank that is the same as the negative pressure coring environment, so as to subsequently test the gas analysis amount in the negative pressure coring environment;

[0029] (2) During the gas desorption process of the coal sample, the gas charging system continuously charges the gas conditioning unit cylinder at a constant pressure, thereby driving the gas conditioning unit piston to move downward continuously, driving the negative pressure unit piston to move downward continuously, so that the negative pressure in the negative pressure unit cylinder cavity above the negative pressure unit piston is adjusted to a constant negative pressure, ensuring that the coal sample in the coal sample tank can complete gas desorption under a certain constant negative pressure condition, thereby calculating and obtaining the cumulative gas desorption amount at different times under a certain constant negative pressure condition, ensuring that the gas content test in the coal sample is accurate;

[0030] (3) The present invention relies on mechanical structure and principle to drive the piston of the gas conditioning unit and the piston of the negative pressure unit to move up and down, does not require electrical control and electrical equipment, improves the safety factor of the working environment, has scientific design, reasonable structure, low cost and simple operation;

[0031] (4) The present invention can adjust the negative pressure in the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston to different negative pressure values ​​according to experimental needs by controlling the outlet pressure of the nitrogen pressure regulating valve, and the adjustment is precise;

[0032] (5) The bottom of the mobile frame of the present invention is equipped with rollers that are supported on the ground and can be folded and stored. In this way, the experimental device can be moved as a whole to meet the complex working environment underground.

[0033] In summary, the present invention can ensure that the coal sample completes gas desorption under a certain constant negative pressure condition, accurately test the gas desorption amount under the negative pressure coring environment, does not require electrical control and does not contain electrical equipment, thereby improving the safety factor of the working environment, and the negative pressure value required for coal sample desorption can be precisely adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the present invention.

[0035] Figure 2 It is a cross-sectional view of the coal sample filtering system of the present invention.

[0036] Figure 3 It is a left side view of the push-up device of the present invention. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are further described below with reference to the accompanying drawings.

[0038] like Figure 1-3As shown, the equipment for accurately testing the amount of gas desorption in the underground negative pressure coring environment by inflation linkage includes a mobile frame 35, a coal sample filtering system, a coal sample tank 1, a negative pressure regulating system and a gas charging system. Rollers 60 that are supported on the ground and can be folded and stored are installed around the bottom of the mobile frame 35. The coal sample inlet of the coal sample filtering system is connected to the outer end of the drill pipe, the coal sample outlet of the coal sample filtering system is connected to the coal sample inlet of the coal sample tank 1, the coal sample outlet of the coal sample tank 1 is connected to the negative pressure suction port of the negative pressure injection system, the coal sample tank 1 is connected to the negative pressure generating chamber of the negative pressure regulating system through a first gas pipeline 58, and the negative pressure regulating chamber of the negative pressure regulating system is connected to the gas charging system through a second gas pipeline 59.

[0039] The coal sample filtering system comprises a filter box 2 and a large coal sample barrel 3. The filter box 2 is fixedly connected to the upper side of the front side wall of the large coal sample barrel 3. A filter screen plate 4 which is higher in the front and lower in the back is arranged in the middle of the filter box 2. A sample outlet 5 located above the filter screen plate 4 is provided in the middle of the rear side plate of the filter box 2. A large coal feed port 6 corresponding to the front and rear of the sample outlet 5 is provided on the upper side of the front side wall of the large coal sample barrel 3. The lower sides of the sample outlet 5 and the large coal feed port 6 are flush with the rear side of the filter screen plate 4. A coal sample inlet pipe 7 located above the filter screen plate 4 is connected to the upper side of the left side plate of the filter box 2. A coal sample outlet pipe 8 located below the filter screen plate 4 is connected to the lower side of the right side plate of the filter box 2. The other end of the coal sample inlet pipe 7 is connected to the outer The ends are connected, and an upper cover 9 is installed on the top of the coal sample tank 1. The left side of the upper cover 9 is provided with a coal sample extraction inlet 62, and the right side of the upper cover 9 is provided with a coal sample extraction outlet 63. A first gas interface 10 is provided at the top center of the upper cover 9. The other end of the coal sample outlet pipe 8 is connected to the coal sample extraction inlet 62, and the coal sample extraction outlet 63 is connected to the negative pressure suction port of the negative pressure injection system through a coal sample suction pipe 11. A first valve 12 is provided on the coal sample outlet pipe 8, and a second valve 13 is provided on the coal sample suction pipe 11. The mesh diameter of the filter plate 4 is smaller than the inner diameter of the coal sample inlet pipe 7, and the sizes of the sample outlet 5 and the large coal feed port 6 are both larger than the inner diameter of the coal sample inlet pipe 7 (to prevent large pieces of coal from blocking the sample outlet 5 and the large coal feed port 6).

[0040] The negative pressure regulating system comprises a negative pressure unit cylinder 14, a negative pressure unit piston 15, a negative pressure unit guide rod 16, a gas regulating unit cylinder 17, a gas regulating unit piston 18 and a gas regulating unit guide rod 19. The center lines of the negative pressure unit cylinder 14, the negative pressure unit piston 15, the negative pressure unit guide rod 16, the gas regulating unit cylinder 17, the gas regulating unit piston 18 and the gas regulating unit guide rod 19 coincide with each other and are arranged vertically. The top of the negative pressure unit cylinder 14 is open, and a sealing cover 20 is threadedly installed on the outer circumference of the upper end of the negative pressure unit cylinder 14. A first O-ring 21 is embedded on the upper end edge of the negative pressure unit cylinder 14 in tight contact with the inner top surface of the sealing cover 20. A second gas interface 22 is provided at the top center of the sealing cover 20. The two ends of the first gas pipeline 58 are respectively connected to the first The gas interface 10 and the second gas interface 22, the first gas pipeline 58 is provided with a first precision negative pressure gauge 23, a third valve 24, a two-way valve 25, a fourth valve 26, a second precision negative pressure gauge 27 and a first exhaust pipeline 28 in sequence from the first gas interface 10 to the second gas interface 22, and the first exhaust pipeline 28 is provided with a fifth valve 29, the negative pressure unit piston 15 is sealingly slidably arranged in the negative pressure unit cylinder 14, the negative pressure generating chamber of the negative pressure regulating system is the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15, the outer circumference of the negative pressure unit piston 15 is in sealing and sliding contact with the inner wall of the negative pressure unit cylinder 14, and two second O-type sealing rings 3 arranged at intervals up and down are fixedly embedded on the outer circumference of the negative pressure unit piston 15 0, the outer circle of the second O-ring 30 is in sealing and sliding contact with the inner wall of the negative pressure unit cylinder 14, the negative pressure unit guide rod 16 is slidably arranged in the negative pressure unit cylinder 14, the upper end of the negative pressure unit guide rod 16 is threaded and fixedly connected to the bottom center of the negative pressure unit piston 15, the negative pressure unit guide rod 16 vertically penetrates and is sealingly and slidably connected to the center of the bottom plate of the negative pressure unit cylinder 14, two third O-rings 31 spaced apart from each other are fixedly embedded in the middle of the bottom plate of the negative pressure unit cylinder 14, the negative pressure unit guide rod 16 vertically passes through the two third O-rings 31 and is in sliding and sealing contact with the inner circles of the two third O-rings 31, the lower side of the right side wall of the negative pressure unit cylinder 14 is connected to the second exhaust pipe 32 located below the negative pressure unit piston 15, the first A sixth valve 33 is provided on the second exhaust pipeline 32, the bottom of the gas-conditioning unit cylinder 17 is open, and a threaded blind hole with an upper open side is provided in the middle of the top of the gas-conditioning unit cylinder 17, the lower end of the negative pressure unit cylinder 14 is threadedly connected in the threaded blind hole, the lower surface of the bottom plate of the negative pressure unit cylinder 14 is in tight sealing contact with the bottom of the threaded blind hole, and a fourth O-ring 34 is co-centerily fixedly embedded on the lower surface of the bottom plate of the negative pressure unit cylinder 14 in tight contact with the bottom of the threaded blind hole, the middle of the outer wall of the negative pressure unit cylinder 14 is fixedly connected to the top center of the moving frame 35, the negative pressure unit guide rod 16 vertically penetrates and is sealed and slidably connected to the center of the top plate of the gas-conditioning unit cylinder 17, and the lower end of the negative pressure unit guide rod 16 extends into the gas-conditioning unit cylinder 17,A fifth O-ring 36 is fixedly embedded in the middle of the top plate of the gas-control unit cylinder 17, the negative pressure unit guide rod 16 vertically passes through the fifth O-ring 36 and is in sliding and sealing contact with the inner circle of the fifth O-ring 36, the gas-control unit piston 18 is sealingly and slidably arranged in the gas-control unit cylinder 17, the negative pressure generating chamber of the negative pressure regulating system is the inner cavity of the gas-control unit cylinder 17 on the upper side of the gas-control unit piston 18, the outer circumference of the gas-control unit piston 18 is in sealing and sliding contact with the inner wall of the gas-control unit cylinder 17, two sixth O-rings 37 spaced apart from each other are fixedly and set on the outer circumference of the gas-control unit piston 18, the outer circle of the sixth O-ring 37 is in sealing and sliding contact with the inner wall of the gas-control unit cylinder 17, the lower end of the negative pressure unit guide rod 16 is threadedly fixedly connected to the gas-control unit piston 1 8, the air-conditioning unit guide rod 19 is arranged directly below the air-conditioning unit piston 18, the upper end of the air-conditioning unit guide rod 19 is threadedly fixedly connected to the bottom center of the air-conditioning unit piston 18, the lower end of the air-conditioning unit guide rod 19 extends out of the lower port of the air-conditioning unit cylinder 17, and the third gas interface 38 is arranged on the right side of the top plate of the air-conditioning unit cylinder 17. The upper edge of the air-conditioning unit guide rod 19 is vertically provided with a scale (not shown in the figure), and the zero scale value is located at the lower end of the air-conditioning unit guide rod 19. Initially, the distance between the air-conditioning unit piston 18 and the inner top surface of the air-conditioning unit cylinder 17 is not less than the distance between the inner top surface of the negative pressure unit piston 15 and the sealing cover 20. The lower side of the moving frame 35 is provided with a push-up device below the air-conditioning unit cylinder 17 and pushing the air-conditioning unit guide rod 19 to move upward.

[0041] The push-up device includes a foot pedal 39, two push-up springs 40, an push-up support plate 41, an push-up guide rod 42, a guide cylinder 43, two first fixed pulleys 44, two second fixed pulleys 45 and two pulling wire ropes 46. The foot pedal 39 is arranged at an angle at the front lower part of the cylinder 17 of the gas-conditioning unit, and the lower side of the foot pedal 39 is hinged to the front lower part of the moving frame 35 through a hinge seat 47. The two push-up springs 40 are spaced left and right and are arranged at an angle at the rear side of the foot pedal 39, and the two ends of the two push-up springs 40 are respectively fixedly connected to the upper side of the rear side of the foot pedal 39 and the moving frame 35. The push-up support plate 41 is horizontally arranged directly below the guide rod 19 of the gas-conditioning unit. The upper surface of the upper push support plate 41 contacts the lower end of the guide rod 19 of the air conditioning unit. The upper push guide rod 42 and the guide cylinder 43 are both vertically arranged directly below the upper push support plate 41. The upper end of the upper push guide rod 42 is fixedly connected to the middle of the lower surface of the upper push support plate 41. The outer circumference of the guide cylinder 43 is fixedly connected to the moving frame 35 through the first bracket 48. The upper push guide rod 42 is slidably connected in the guide cylinder 43 through the same center. The left and right sides of the upper push support plate 41 are both provided with a second bracket 49 fixedly connected to the moving frame 35. The two first fixed pulleys 44 are respectively rotatably connected to the tops of the two second brackets 49 and are located on the upper left and right sides of the upper push support plate 41. The two first fixed pulleys A third bracket 50 fixedly connected to the mobile frame 35 is provided directly in front and below each of the two third brackets 50, and the two second fixed pulleys 45 are rotatably connected to the tops of the two third brackets 50 respectively. The height of the second fixed pulley 45 is lower than that of the first fixed pulley 44. The rotating shafts of the two first fixed pulleys 44 and the two second fixed pulleys 45 are both horizontally arranged in the left and right directions. The two pulling steel wire ropes 46 are symmetrically arranged in the left and right directions and are both arranged in the front and rear directions. The front end of the pulling steel wire rope 46 on the left side is fixedly connected to the left side portion of the upper side edge of the foot pedal 39, and the pulling steel wire rope 46 on the left side extends backward and is successively wound around the upper side portion of the second fixed pulley 45 on the left and the first fixed pulley 44 on the left. On the upper side, the lifting wire rope 46 on the left side passes around the upper side of the first fixed pulley 44 on the left side and then extends vertically downward. The lower end of the lifting wire rope 46 on the left side is fixedly connected to the middle left side of the upper surface of the upper push support plate 41, and the front end of the lifting wire rope 46 on the right side is fixedly connected to the right side of the upper side edge of the foot pedal 39. The lifting wire rope 46 on the right side extends backward and is successively wrapped around the upper side of the second fixed pulley 45 on the right side and the upper side of the first fixed pulley 44 on the right side. The lifting wire rope 46 on the right side passes around the upper side of the first fixed pulley 44 on the right side and then extends vertically downward. The lower end of the lifting wire rope 46 on the right side is fixedly connected to the middle right side of the upper surface of the upper push support plate 41.

[0042] The inflation system includes a high-pressure nitrogen bottle 51. The two ends of the second gas pipeline 59 are respectively connected to the gas outlet of the high-pressure nitrogen bottle 51 and the third gas interface 38. The second gas pipeline 59 is provided with a nitrogen pressure regulating valve 52, a first precision pressure gauge 53, a seventh valve 54, a second precision pressure gauge 55 and a third exhaust pipeline 56 in sequence along the gas flow direction. The third exhaust pipeline 56 is provided with an eighth valve 57.

[0043] The method for testing the gas desorption amount under negative pressure coring environment with precise adjustment of negative pressure by adopting the above technical solution specifically comprises the following steps:

[0044] (1) Assemble the equipment for accurately testing the desorption amount of gas in the underground negative pressure coring environment at the underground coal mining site;

[0045] (2) Exhaust the indoor air generated by the negative pressure regulating system;

[0046] (III) The coal sample is filtered by the coal sample filtration system and then drawn into the coal sample tank 1 through the negative pressure injection system, so that the coal sample tank 1 is filled with coal sample 61 and is in a negative pressure environment. The negative pressure value is recorded as p 0;

[0047] (IV) Inflate the negative pressure regulating chamber of the negative pressure regulating system through the inflation system, so that the negative pressure generating chamber of the negative pressure regulating system forms the same negative pressure environment as that in the coal sample tank 1. The negative pressure value is recorded as p 0;

[0048] (V) Connect the coal sample tank 1 to the negative pressure generating chamber of the negative pressure regulating system, and continuously inflate the negative pressure regulating chamber of the negative pressure regulating system through the inflation system to control the negative pressure in the negative pressure generating chamber of the negative pressure regulating system to remain stable. The coal sample in the coal sample tank 1 is at a negative pressure value of p Desorption under 0 conditions, the negative pressure value is calculated p 0 at different times t n0 Cumulative gas desorption Q n0 ;

[0049] (VI) Negative pressure value is p After the gas desorption test under 0 conditions is completed, the inflation system stops inflating, and the negative pressure generating chamber and the negative pressure regulating chamber of the negative pressure regulating system are connected to the outside atmosphere;

[0050] (VII) Use Origin drawing software to draw the negative pressure value p Cumulative gas desorption under 0 conditions Q n0 About time t n0 The scatter curve of

[0051] (VIII) Clean out the desorbed coal sample 61 in the coal sample tank 1, repeat steps (II) to (VII), and draw new coal sample 61 into the coal sample tank 1. The negative pressure value in the coal sample tank 1 is recorded as p n , through the inflation system, the negative pressure of the negative pressure regulating system is adjusted to the indoor negative pressure value p n And keep it constant, calculate the negative pressure value p n At different times under different conditions t nn Cumulative gas desorption Q nn , and plot the negative pressure value as p n Cumulative gas desorption under the condition Q nn About time t nn The scatter curve of .

[0052] Step (ii) is specifically as follows: initially, the first valve 12, the second valve 13, the third valve 24, the fourth valve 26, the fifth valve 29, the sixth valve 33, the seventh valve 54 and the eighth valve 57 are all in a closed state, the fifth valve 29, the sixth valve 33 and the eighth valve 57 are opened, and then the operator steps on the foot pedal 39 to flip the foot pedal 39 backward and downward, so that the foot pedal 39 pulls the front ends of the two lifting wire ropes 46 downward, and then the rear ends of the two lifting wire ropes 46 lift the upper push support plate 41 upward, so that the upper push support plate 41 moves upward, and then the upper push support plate 41 pushes the gas The air-conditioning unit guide rod 19 moves upward, and the upper push rod 42 slides in the guide cylinder 43 to guide. The air-conditioning unit guide rod 19 pushes the air-conditioning unit piston 18 to move upward. The air-conditioning unit piston 18 moves upward to compress the air in the air-conditioning unit cylinder 17 on the upper side thereof, so that the air in the air-conditioning unit cylinder 17 on the upper side of the air-conditioning unit piston 18 is discharged through the third gas interface 38, the second gas pipeline 59 and the third exhaust pipeline 56. At the same time, the air-conditioning unit piston 18 drives the negative pressure unit guide rod 16 to move upward, and the negative pressure unit guide rod 16 pushes the negative pressure unit piston 15 to move upward, then the negative pressure unit piston 15 The inner cavity of the negative pressure unit cylinder 14 on the lower side becomes negative pressure, so that the outside air is sucked into the inner cavity of the negative pressure unit cylinder 14 on the lower side of the negative pressure unit piston 15 through the second exhaust pipe 32, so that the inner cavity of the negative pressure unit cylinder 14 on the lower side of the negative pressure unit piston 15 is balanced with the external atmospheric pressure, and the negative pressure unit piston 15 moves upward to compress the air in the negative pressure unit cylinder 14 on the upper side thereof, so that the air in the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15 is discharged through the second gas interface 22, the first gas pipe 58 and the first exhaust pipe 28 until the negative pressure unit piston 15 moves upward to a point where it cannot move. , that is, until the upper surface of the negative pressure unit piston 15 is in close contact with the inner top surface of the sealing cover 20, so that the air in the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15 can be exhausted, and then, the foot pedal 39 is released, and the foot pedal 39 is flipped forward and reset under the reset action of the top pressure spring 40, and the upper push support plate 41 and the upper push guide rod 42 move downward and return to the initial position under the action of gravity, and the upper push support plate 41 is separated from the air conditioning unit guide rod 19, the fifth valve 29 and the eighth valve 57 are closed, and the scale value corresponding to the lower port of the air conditioning unit cylinder 17 on the air conditioning unit guide rod 19 is recorded at this time h 0, that is, the length of the air conditioning unit guide rod 19 extending out of the air conditioning unit cylinder 17 is h 0.

[0053] Step (iii) is specifically as follows: open the first valve 12 and the second valve 13, start the negative pressure ejection system, the negative pressure ejection system extracts the coal peeled off during the drilling process of the drill bit through the drill rod, and the coal blocks enter the upper side of the filter box 2 through the coal sample inlet pipe 7, and the coal blocks fall onto the filter screen plate 4 for filtration, and the large coal blocks in the filter box 2 directly roll down along the filter screen plate 4 and fall into the large coal sample bucket 3 through the sample outlet 5 and the large coal feed port 6, while the small coal blocks and coal powder pass downward. The mesh of the filter screen 4 falls to the lower side of the filter box 2 and then is output through the coal sample outlet pipe 8. The small pieces of coal and coal powder are drawn into the coal sample tank 1 along the coal sample outlet pipe 8. When the coal sample tank 1 is filled with small pieces of coal and coal powder, the first valve 12, the second valve 13 and the negative pressure injection system are closed, and the small pieces of coal and coal powder in the coal sample tank 1 are used as the coal sample 61 to be tested. At this time, the coal sample 61 in the coal sample tank 1 is in a negative pressure environment, and the negative pressure value of the first precision negative pressure gauge 23 is recorded as p 0.

[0054] Step (IV) is specifically as follows: open the fourth valve 26 and the main valve on the top of the high-pressure nitrogen cylinder 51, adjust the nitrogen pressure regulating valve 52, so that the outlet of the nitrogen pressure regulating valve 52 produces a constant outlet pressure, open the seventh valve 54, and then the nitrogen in the high-pressure nitrogen cylinder 51 is pressure-regulated by the nitrogen pressure regulating valve 52 and then charged into the cylinder 17 of the gas-adjusting unit through the second gas pipeline 59, then the gas pressure in the cylinder 17 of the gas-adjusting unit increases, and the gas in the cylinder 17 of the gas-adjusting unit pushes the piston 18 of the gas-adjusting unit to move downward, and the piston 18 of the gas-adjusting unit drives the guide rod 16 of the negative pressure unit to move downward, and the guide rod 16 of the negative pressure unit drives When the negative pressure unit piston 15 moves downward, the negative pressure unit piston 15 moves downward to compress the air in the negative pressure unit cylinder 14 below it, so that the air in the negative pressure unit cylinder 14 below the negative pressure unit piston 15 is discharged through the second exhaust pipe 32. At the same time, a negative pressure environment is formed in the inner cavity of the negative pressure unit cylinder 14 above the negative pressure unit piston 15. The negative pressure value of the second precision negative pressure gauge 27 is observed, and the nitrogen pressure regulating valve 52 is fine-tuned until the inner cavity of the negative pressure unit cylinder 14 above the negative pressure unit piston 15 produces the same negative pressure environment as that in the coal sample tank 1, that is, the negative pressure value of the second precision negative pressure gauge 27 is adjusted to p 0, and record the pressure value of the second precision pressure gauge 55 at this time P 0, then stop fine-tuning the nitrogen pressure regulating valve 52, and the outlet pressure of the nitrogen pressure regulating valve 52 is also P 0 and constant, that is, the pressure value of the first precision pressure gauge 53 is also P 0, at this time, the negative pressure in the coal sample tank 1 is the same as the negative pressure in the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15, the negative pressure unit piston 15 and the gas conditioning unit piston 18 are balanced in force, and the gas conditioning unit piston 18 and the negative pressure unit piston 15 both stop moving.

[0055] Step (V) is as follows: Open the third valve 24, so that the coal sample tank 1 is connected to the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15 through the first gas pipeline 58, and the coal sample 61 in the coal sample tank 1 is p 0, the desorbed gas will enter the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15 through the first gas pipeline 58, then the pressure in the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15 will increase, and the negative pressure will decrease. The upward suction force formed by the negative pressure in the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15 is smaller than the downward thrust formed by the positive pressure in the gas regulating unit cylinder 17, and the negative pressure unit piston 15 and the gas regulating unit piston 18 will lose balance. Since the outlet pressure of the nitrogen pressure regulating valve 52 is constant at P 0, the nitrogen in the high-pressure nitrogen cylinder 51 continues to be filled into the gas-adjusting unit cylinder 17, and the gas in the gas-adjusting unit cylinder 17 continuously pushes the gas-adjusting unit piston 18 to move downward, and the gas-adjusting unit piston 18 drives the negative pressure unit piston 15 to move downward together through the negative pressure unit guide rod 16, thereby increasing the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15, and the negative pressure can be instantly adjusted to p 0 Make the negative pressure unit piston 15 and the gas adjustment unit piston 18 always balanced. During this process, every time t , then record the scale value on the gas conditioning unit guide rod 19 corresponding to the lower end of the gas conditioning unit cylinder 17 h n0 (n=1, 2, 3, 4, 5, 6...), until the gas conditioning unit piston 18 stops moving, it means that the coal sample 61 in the coal sample tank 1 is under negative pressure. p 0, the gas desorption is completed, then t n0 The scale value corresponding to the lower port of the gas conditioning unit cylinder 17 on the gas conditioning unit guide rod 19 is h n0 Subtract the scale value corresponding to when the piston 18 of the gas conditioning unit moves upward to the highest point in step (iii) h 0, you can get a certain moment t n0 The cumulative distance that the piston 18 of the gas conditioning unit drives the guide rod 16 of the negative pressure unit to move downward, that is, at a certain moment t n0 The cumulative distance that the negative pressure unit piston 15 moves downward is recorded as h n0 - h 0, then the negative pressure value can be calculated by the formula p 0 at different times t n0 Cumulative gas desorption Q n0 ,Q n0 =π r 2 ( h n0 - h 0), r is the inner diameter of the negative pressure unit cylinder 14.

[0056] Step (six) is as follows: the negative pressure value is p After the gas desorption test under the condition of 0 is completed, the third valve 24, the fourth valve 26, the seventh valve 54 and the main valve on the top of the high-pressure nitrogen bottle 51 are closed to stop the nitrogen in the high-pressure nitrogen bottle 51 from being charged into the gas conditioning unit cylinder 17, and then the fifth valve 29 and the eighth valve 57 are opened to make the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15 and the inner cavity of the gas conditioning unit cylinder 17 both communicate with the outside atmosphere;

[0057] In step (eight), the negative pressure of the negative pressure regulating system is adjusted to a negative pressure value in the room by means of the inflation system. p n The specific implementation method of maintaining a constant pressure is the same as the operation process in step (iv): open the fourth valve 26 and the main valve on the top of the high-pressure nitrogen cylinder 51, adjust the nitrogen pressure regulating valve 52, so that the outlet of the nitrogen pressure regulating valve 52 produces a constant outlet pressure, open the seventh valve 54, and the nitrogen in the high-pressure nitrogen cylinder 51 is pressure-regulated by the nitrogen pressure regulating valve 52 and then charged into the cylinder 17 of the gas-adjusting unit through the second gas pipeline 59, then the gas pressure in the cylinder 17 of the gas-adjusting unit increases, and the gas in the cylinder 17 of the gas-adjusting unit pushes the piston 18 of the gas-adjusting unit to move downward, and the piston 18 of the gas-adjusting unit drives the guide rod 16 of the negative pressure unit to move downward, and the negative pressure unit 18 is pressed downward. The negative pressure unit guide rod 16 drives the negative pressure unit piston 15 to move downward, and the negative pressure unit piston 15 moves downward to compress the air in the negative pressure unit cylinder 14 below it, so that the air in the negative pressure unit cylinder 14 below the negative pressure unit piston 15 is discharged through the second exhaust pipe 32. At the same time, the inner cavity of the negative pressure unit cylinder 14 above the negative pressure unit piston 15 forms a negative pressure environment. Observe the negative pressure value of the second precision negative pressure gauge 27, and fine-tune the nitrogen pressure regulating valve 52 until the inner cavity of the negative pressure unit cylinder 14 above the negative pressure unit piston 15 produces the same negative pressure environment as that in the coal sample tank 1, that is, the negative pressure value of the second precision negative pressure gauge 27 is adjusted to p n , and record the pressure value of the second precision pressure gauge 55 at this time P n , then stop fine-tuning the nitrogen pressure regulating valve 52, and the outlet pressure of the nitrogen pressure regulating valve 52 is also P n And constant, that is, the pressure value of the first precision pressure gauge 53 is also P nAt this time, the negative pressure in the coal sample tank 1 is the same as the negative pressure in the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15, the negative pressure unit piston 15 and the gas conditioning unit piston 18 are balanced in force, and the gas conditioning unit piston 18 and the negative pressure unit piston 15 both stop moving.

[0058] The drill rod and the negative pressure ejection system are both conventional technologies in the art, and their specific structures and working principles are not described in detail and are not shown in the figures.

[0059] It should be noted that the force balance between the negative pressure unit piston 15 and the gas-adjusting unit piston 18 means that, for the negative pressure unit piston 15, the negative pressure in the inner cavity of the negative pressure unit cylinder 14 on the upper side of the negative pressure unit piston 15 forms an upward suction force, the gravity of the negative pressure unit piston 15, the friction force of the negative pressure unit piston 15 and the pulling force generated by the negative pressure unit guide rod 16 on the negative pressure unit piston 15 make the negative pressure unit piston 15 achieve force balance. Similarly, for the gas-adjusting unit piston 18, the positive pressure in the gas-adjusting unit cylinder 17 forms a downward thrust on the gas-adjusting unit piston 18, the gravity of the gas-adjusting unit piston 18, the gravity of the gas-adjusting unit guide rod 19, the friction force of the gas-adjusting unit piston 18 and the pulling force generated by the negative pressure unit guide rod 16 on the gas-adjusting unit piston 18 make the gas-adjusting unit piston 18 achieve force balance.

[0060] The folding and storage of the roller 60 requires a folding mechanism. The folding mechanism is a conventional mechanical structure, similar to the kickstand of a bicycle. The folding mechanism is hinged at the bottom of the mobile frame 35. When it needs to be moved, the folding mechanism drives the roller 60 to flip downward so that the roller 60 is rolled and supported on the ground. When it is moved into place, the folding mechanism drives the roller 60 to flip upward in the opposite direction so that the roller 60 is stored on the mobile frame and off the ground, thereby making the bottom of the mobile frame directly fixed and supported on the ground. The structure of the folding mechanism is not repeated here, and those skilled in the art can implement this technology.

[0061] The present invention can ensure that the coal sample 61 completes gas desorption under a certain constant negative pressure condition, accurately test the gas desorption amount under the negative pressure coring environment, does not require electrical control and does not contain electrical equipment, thereby improving the safety factor of the working environment. The negative pressure value required for the desorption of the coal sample 61 can be precisely adjusted.

[0062] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. Equipment for accurately testing the amount of gas desorption in the underground negative pressure coring environment by inflation linkage, characterized by: It includes a mobile frame, a coal sample filtering system, a coal sample tank, a negative pressure regulating system and an inflation system. The bottom of the mobile frame is equipped with rollers that are supported on the ground and can be folded and stored. The coal sample tank, the negative pressure regulating system and the inflation system are all arranged on the mobile frame. The coal sample inlet of the coal sample filtering system is connected to the outer end of the drill rod, the coal sample outlet of the coal sample filtering system is connected to the coal sample inlet of the coal sample tank, the coal sample outlet of the coal sample tank is connected to the negative pressure suction port of the negative pressure injection system, the coal sample tank is connected to the negative pressure generating chamber of the negative pressure regulating system through a first gas pipeline, and the negative pressure regulating chamber of the negative pressure regulating system is connected to the inflation system through a second gas pipeline. The coal sample filtering system includes a filter box and a large coal sample barrel. The filter box is fixedly connected to the upper side of the front side wall of the large coal sample barrel. A filter plate with a high front and a low back is arranged in the middle of the filter box. A sample outlet located above the filter plate is opened in the middle of the rear side plate of the filter box. A large coal feed port corresponding to the front and rear of the sample outlet is opened on the upper side of the front side wall of the large coal sample barrel. The lower sides of the sample outlet and the large coal feed port are flush with the rear side of the filter plate. The upper side of the left side plate of the filter box is connected to a coal sample inlet pipe located above the filter plate, and the lower side of the right side plate of the filter box is connected to a coal sample outlet pipe located below the filter plate. The other end of the coal sample inlet pipe is connected with the outer end of the drill pipe, an upper cover is installed on the top of the coal sample tank, a coal sample extraction inlet is provided on the left side of the upper cover, a coal sample extraction outlet is provided on the right side of the upper cover, and a first gas interface is provided at the top center of the upper cover, the other end of the coal sample outlet pipe is connected with the coal sample extraction inlet, and the coal sample extraction outlet is connected with the negative pressure suction port of the negative pressure injection system through a coal sample suction pipe, a first valve is provided on the coal sample outlet pipe, and a second valve is provided on the coal sample suction pipe. The mesh diameter of the filter plate is smaller than the inner diameter of the coal sample inlet pipe, and the sizes of the sample outlet and the bulk coal feed port are both larger than the inner diameter of the coal sample inlet pipe.

2. The equipment for accurately testing the amount of gas desorption in a downhole negative pressure coring environment by means of inflation linkage according to claim 1 is characterized in that: The negative pressure regulating system comprises a negative pressure unit cylinder, a negative pressure unit piston, a negative pressure unit guide rod, a gas-adjusting unit cylinder, a gas-adjusting unit piston and a gas-adjusting unit guide rod. The center lines of the negative pressure unit cylinder, the negative pressure unit piston, the negative pressure unit guide rod, the gas-adjusting unit cylinder, the gas-adjusting unit piston and the gas-adjusting unit guide rod coincide and are arranged vertically. The top of the negative pressure unit cylinder is open. A sealing cover is threadedly installed on the outer circumference of the upper end of the negative pressure unit cylinder. A first O-ring is embedded on the upper end edge of the negative pressure unit cylinder in tight contact with the inner top surface of the sealing cover. A second gas interface is arranged at the top center of the sealing cover. Two ends of the first gas pipeline are respectively connected to the first gas interface and the second gas interface. The first gas pipeline is provided with gaskets in sequence from the first gas interface to the second gas interface. The first precision negative pressure gauge, the third valve, the two-way valve, the fourth valve, the second precision negative pressure gauge and the first exhaust pipeline, the first exhaust pipeline is provided with a fifth valve, the negative pressure unit piston is sealingly slidably arranged in the negative pressure unit cylinder, the negative pressure generating chamber of the negative pressure regulating system is the inner cavity of the negative pressure unit cylinder on the upper side of the negative pressure unit piston, the outer circumference of the negative pressure unit piston is in sealing and sliding contact with the inner wall of the negative pressure unit cylinder, two second O-rings spaced apart up and down are fixedly embedded on the outer circumference of the negative pressure unit piston, the outer circle of the second O-ring is in sealing and sliding contact with the inner wall of the negative pressure unit cylinder, the negative pressure unit guide rod is slidably arranged in the negative pressure unit cylinder, the upper end of the negative pressure unit guide rod is threadedly fixedly connected to the bottom center of the negative pressure unit piston, and the negative pressure unit guide rod is vertically connected to the negative pressure unit cylinder. A straight-through sealing sliding connection is connected in the center of the bottom plate of the negative pressure unit cylinder, and two third O-rings spaced apart are fixedly embedded in the middle of the bottom plate of the negative pressure unit cylinder. The negative pressure unit guide rod vertically passes through the two third O-rings and is in sliding sealing contact with the inner circles of the two third O-rings. The lower side of the right side wall of the negative pressure unit cylinder is connected to the second exhaust pipeline located below the negative pressure unit piston, and a sixth valve is arranged on the second exhaust pipeline. The bottom of the gas conditioning unit cylinder is open, and a threaded blind hole with an open upper side is provided in the middle of the top of the gas conditioning unit cylinder. The lower end of the negative pressure unit cylinder is matched with a thread connection in the threaded blind hole, and the lower surface of the bottom plate of the negative pressure unit cylinder is in tight sealing contact with the bottom of the threaded blind hole, and the lower surface of the bottom plate of the negative pressure unit cylinder is in tight sealing contact with the bottom of the threaded blind hole. A fourth O-ring is fixedly embedded in the same center as above and is in tight contact with the bottom of the threaded blind hole. The middle part of the outer wall of the negative pressure unit cylinder is fixedly connected to the top center of the mobile frame. The negative pressure unit guide rod vertically penetrates and is sealed and slidably connected to the center of the top plate of the gas-conditioning unit cylinder. The lower end of the negative pressure unit guide rod extends into the gas-conditioning unit cylinder. A fifth O-ring is fixedly embedded in the middle part of the top plate of the gas-conditioning unit cylinder. The negative pressure unit guide rod vertically penetrates the fifth O-ring and is in sliding and sealing contact with the inner circle of the fifth O-ring. The gas-conditioning unit piston is sealingly and slidably arranged in the gas-conditioning unit cylinder. The negative pressure generating chamber of the negative pressure regulating system is the inner cavity of the gas-conditioning unit cylinder on the upper side of the gas-conditioning unit piston. The outer circumference of the gas-conditioning unit piston is in sealing and sliding contact with the inner wall of the gas-conditioning unit cylinder.Two sixth O-rings are fixedly mounted on the outer circumference of the gas-adjusting unit piston and spaced apart from each other. The outer circumference of the sixth O-ring is in sealing and sliding contact with the inner wall of the gas-adjusting unit cylinder. The lower end of the negative pressure unit guide rod is threadedly fixedly connected to the top center of the gas-adjusting unit piston. The gas-adjusting unit guide rod is arranged directly below the gas-adjusting unit piston. The upper end of the gas-adjusting unit guide rod is threadedly fixedly connected to the bottom center of the gas-adjusting unit piston. The lower end of the gas-adjusting unit guide rod extends out of the lower port of the gas-adjusting unit cylinder. The right side of the top plate of the gas-adjusting unit cylinder is provided with a third gas interface. A scale is vertically arranged on the upper edge of the gas-adjusting unit guide rod, and the zero scale value is located at the lower end of the gas-adjusting unit guide rod. Initially, the distance between the gas-adjusting unit piston and the inner top surface of the gas-adjusting unit cylinder is not less than the distance between the negative pressure unit piston and the inner top surface of the sealing cover. The lower side of the mobile frame is provided with an upward push device located at the front lower part of the gas-adjusting unit cylinder and pushing the gas-adjusting unit guide rod to move upward.

3. The equipment for accurately testing the amount of gas desorption in a downhole negative pressure coring environment by means of inflation linkage according to claim 2 is characterized in that: The pushing device includes a foot pedal, two pressure springs, an upward pushing support plate, an upward pushing guide rod, a guide cylinder, two first fixed pulleys, two second fixed pulleys and two pulling wire ropes. The foot pedal is arranged at an angle at the front lower part of the cylinder of the gas-conditioning unit with a lower front and a higher rear. The lower side of the foot pedal is hinged to the front lower part of the moving frame through a hinge seat. The two pressure springs are spaced left and right and are arranged at the rear side of the foot pedal with a higher front and a lower rear. The two ends of the two pressure springs are respectively fixedly connected to the upper side of the rear side of the foot pedal and the moving frame. The upward pushing support plate is horizontally arranged just below the guide rod of the gas-conditioning unit. The upper The upper push guide rod and the guide cylinder are both vertically arranged directly below the upper push support plate, and the upper end of the upper push guide rod is fixedly connected to the middle of the lower surface of the upper push support plate. The outer circumference of the guide cylinder is fixedly connected to the moving frame through the first bracket, and the upper push guide rod is slidably connected in the guide cylinder concentrically. A second bracket fixedly connected to the moving frame is arranged on the left and right sides of the upper push support plate, and the two first fixed pulleys are respectively rotatably connected to the tops of the two second brackets and are located on the upper left and right sides of the upper push support plate. A The two second fixed pulleys are rotatably connected to the tops of the two third brackets respectively, the height of the second fixed pulley is lower than the height of the first fixed pulley, the rotating shafts of the two first fixed pulleys and the two second fixed pulleys are horizontally arranged in the left and right directions, the two lifting steel ropes are symmetrically arranged in the left and right directions and are arranged in the front and rear directions, the front end of the lifting steel rope on the left side is fixedly connected to the left side part of the upper side edge of the foot pedal, the lifting steel rope on the left side extends backward and is successively wound around the upper side part of the second fixed pulley on the left side and the upper side part of the first fixed pulley on the left side, and the left side The lifting wire rope passes around the upper side of the first fixed pulley on the left and then extends vertically downward. The lower end of the lifting wire rope on the left is fixedly connected to the middle left part of the upper surface of the upper push support plate, and the front end of the lifting wire rope on the right is fixedly connected to the right side of the upper side edge of the foot pedal. The lifting wire rope on the right extends backward and is successively wrapped around the upper side of the second fixed pulley on the right and the upper side of the first fixed pulley on the right. The lifting wire rope on the right passes around the upper side of the first fixed pulley on the right and then extends vertically downward. The lower end of the lifting wire rope on the right is fixedly connected to the middle right part of the upper surface of the upper push support plate.

4. The equipment for accurately testing the amount of gas desorption in a downhole negative pressure coring environment by means of inflation linkage according to claim 3 is characterized in that: The inflation system includes a high-pressure nitrogen bottle. Both ends of the second gas pipeline are respectively connected to the outlet of the high-pressure nitrogen bottle and the third gas interface. A nitrogen pressure regulating valve, a first precision pressure gauge, a seventh valve, a second precision pressure gauge and a third exhaust pipeline are sequentially arranged on the second gas pipeline along the gas flow direction. The third exhaust pipeline is provided with an eighth valve.

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