Underground refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and dilution gas

Abstract

The invention provides an underground refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas, which comprises a ventilation device, a temperature sensing device and a gas sensing device, the temperature sensing device is vertically suspended and mounted at an air return corner of a coal mining surface, and the gas sensing device is mounted at the air return corner. The ventilation device is hung in an unshielded area of a roadway at an air return corner, the ventilation device comprises a first-stage spiral blade, a second-stage spiral blade, a refrigeration pipe and a flow meter, the temperature sensing device comprises an anti-explosion shell, a sealing layer, a thermosensitive element and a temperature sensing probe, and the gas sensing device comprises a shell, a filtering part and a vent hole group. A vent hole group is formed in the front end of the shell, gas concentration monitoring is completed through the vent hole group, and a filtering part is connected between the vent hole group and an inner cavity of the shell. When the ventilation device is used, underground compressed air is used as a single power source when the ventilation device is started, electric power or water is not used for driving, no harsh requirements for water quality and water pressure exist, and the ventilation device is economical and practical.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine ventilation, and particularly relates to a refrigeration pneumatic ventilation system for preventing coal spontaneous combustion and diluting gas underground. Background Technique

[0002] The basic tasks of mine ventilation are to supply sufficient fresh air underground, meet the oxygen needs of personnel, dilute harmful gases and dust underground, ensure safe production, regulate the underground climate, and create a good working environment. In order to make the underground air flow along the designated route for distribution, it is necessary to build structures that guide and control the air flow, namely ventilation facilities, in certain roadways. It is divided into facilities for guiding air flow and blocking air flow. The ventilation systems of newly built large mines are mainly diagonal and sectional types, and the ventilation systems of reconstructed and expanded production mines are mainly mixed types. The most commonly used is the ventilator.

[0003] Among the existing coal mine safety ventilation equipment, there are very few ventilators for the return air corner, and the conditions it needs to meet are as follows:

[0004] 1. Identify toxic and harmful gases. If the concentration of toxic and harmful gases is too high, the equipment starts to work, thus avoiding problems such as explosion caused by too high concentration. Therefore, a gas concentration sensor is added at the return air corner to achieve self-starting when the concentration of harmful gases such as CH4, CO, SO2, etc. in the return air corner is too high, and dilute the toxic and harmful gases.

[0005] 2. Have a cooling device. There is residual coal in the return air corner, which may lead to coal spontaneous combustion. Therefore, a refrigeration pipe is added to the ventilator. At the same time, a temperature sensing device is installed at a suitable position in the return air corner to achieve self-starting of the device for refrigeration when the temperature is too high, so as to achieve the effect of energy conservation and emission reduction.

[0006] Based on this, a refrigeration pneumatic ventilation system for preventing coal spontaneous combustion and diluting gas underground is proposed. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a refrigeration pneumatic ventilation system for preventing coal spontaneous combustion and diluting gas underground in view of the deficiencies of the above-mentioned prior art, so as to solve the problems put forward in the above background technique.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is: a refrigeration pneumatic ventilation system for preventing coal spontaneous combustion and diluting gas underground, including a ventilation device, a temperature sensing device, and a gas sensing device. The temperature sensing device is vertically suspended and installed at the return air corner of the coal mining face, the gas sensing device is installed at the return air corner, and the ventilation device is suspended and hoisted in the unobstructed area of the roadway at the return air corner;

[0009] Among them, the ventilation device includes a first-stage spiral blade, a second-stage spiral blade refrigeration pipe, and a flowmeter. The first-stage spiral blade and the second-stage spiral blade are respectively installed on the central axis of the fan through the cooperation of a bearing seat, a bearing, a pin, and a mounting plate. The refrigeration pipe is a spiral coil pipe, and the refrigeration pipe is installed on the outer side of the middle section of the central axis of the fan. The flowmeter is installed in the rear area of the second-stage spiral blade in the ventilation device;

[0010] The temperature sensing device includes an explosion-proof shell, a sealing layer, a thermosensitive element, and a temperature sensing probe. The thermosensitive element and the temperature sensing probe form a temperature sensing component. The temperature sensing component is installed in the sealing layer. The explosion-proof shell is wrapped outside the sealing layer, and the outer end of the temperature sensing probe is in contact with the external environment;

[0011] The gas sensing device includes a housing, a filtering component, and a ventilation hole group. The ventilation hole group is installed at the front end of the housing, and the gas concentration monitoring is completed through the ventilation hole group. A filtering component is connected between the ventilation hole group and the inner cavity of the housing.

[0012] The pneumatic motor is of a vane type structure, including a stator, a rotor, vanes, a housing, a front end cover, a rear end cover, an exhaust pipe shaft, and bearings. Its stator is fixed to the housing, and the rotor rotates with low friction through bearings. Compressed air enters the eccentric chamber between the stator and the rotor through the air inlet of the pneumatic motor, pushes the vanes to extend outwards, drives the rotor to rotate and outputs mechanical energy to the central axis of the fan. The discharged gas passes through the air outlet of the pneumatic motor through a trachea and is guided to the exhaust pipe shaft of the rear end cover, and finally converges into the inner cavity of the central axis of the fan to provide a cooling medium for the refrigeration pipe.

[0013] As a further description of the present invention, the distance between the temperature sensing device and the roof of the return air corner is not greater than 300 mm, the distance from the roadway wall is not less than 200 mm, and the alarm value of the temperature sensing device is set at 30 °C.

[0014] As a further description of the present invention, the gas sensing device is installed at a distance not greater than 800 mm from the old goaf and the roof cutting pillar at the return air corner. At the same time, the hanging position of the gas sensing device is not more than 300 mm from the roof, not less than 200 mm from the roadway side, and not less than 1 m above the arch base line of the roadway when hanging in an arched roadway.

[0015] As a further description of the present invention, filters are installed on both sides of the ventilation device, and a support rod is installed at the bottom end of the ventilation device. The central axis of the fan is installed on the support rod, and a support plate is also installed at the bottom end of the support rod.

[0016] As a further illustration of the present invention, a first deflector is also installed outside the central axis of the fan in the ventilation device. The first deflector is located between the first-stage spiral blade and the second-stage spiral blade. The guidance and control of the air flow direction are completed through the first deflector. A pneumatic motor is also installed on the central axis of the fan. The pneumatic motor includes a stator, a rotor, blades, a housing, a rear end cover, a front end cover, an exhaust pipe shaft and bearings. The stator is fixed inside the housing to form an eccentric chamber. The rotor is installed at the center inside the housing through bearings. Radial grooves are formed on the rotor, and the blades are embedded in the grooves. The rotor is supported by bearings and drives the central axis of the fan to rotate. The air inlet of the pneumatic motor is communicated with the compressed air inlet. Compressed air pushes the blades to drive the rotor to rotate, and the gas is discharged through the air outlet of the pneumatic motor and is communicated to the exhaust pipe shaft through a trachea. The exhaust pipe shaft penetrates through the rear end cover and the front end cover and is communicated with the central axis of the fan, and enters the inner cavity of the central axis of the fan through the exhaust pipe shaft to drive the refrigeration pipe to complete the cooling cycle.

[0017] As a further illustration of the present invention, the pneumatic motor is installed at the front end of the central axis of the fan and is fixed by bolts. The air inlet of the pneumatic motor is connected to the compressed air inlet through a pressure-resistant trachea. After compressed air enters, it pushes the blades to drive the rotor to rotate, driving the central axis of the fan to rotate synchronously. After the compressed gas is discharged from the air outlet of the pneumatic motor, it enters the inner cavity of the central axis of the fan through the exhaust pipe shaft and flows along the central axis to the inlet of the refrigeration pipe. The exhaust pipe shaft and the central axis of the fan are connected through a sealing flange to ensure no air leakage. The vortex tube in the refrigeration pipe utilizes the residual pressure and low-temperature characteristics of the compressed gas to further reduce the air flow temperature, forming a closed-loop cooling system.

[0018] As a further illustration of the present invention, a refrigeration pipe intelligent valve is installed at the inlet connected to the refrigeration pipe. A vortex tube is also installed inside the refrigeration pipe. Underground compressed air enters the central axis of the fan from the compressed air inlet, successively passes through the first-stage spiral blade, the refrigeration pipe and the second-stage spiral blade, and flows along the inner side of the central axis of the fan. Subsequently, it is guided by the deflector between the first-stage spiral blade and the second-stage spiral blade. The first-stage spiral blade is located on the inlet side of the refrigeration pipe, and the second-stage spiral blade is located on the outlet side of the refrigeration pipe. After the compressed air is cooled by the refrigeration pipe, it is accelerated by the first-stage spiral blade and the second-stage spiral blade to form a directional air flow. The central axis of the fan and the inlet pipe of the vortex tube in the refrigeration pipe are connected through a hose. A second deflector is provided at the air outlet of the refrigeration pipe. When the compressed gas enters and passes through the hose and enters the vortex tube from the inlet pipe, the gas rotates inside the vortex tube. At the same time, the gas is cooled and transformed into low-temperature and low-pressure gas, and flows out with the outlet of the refrigeration pipe for refrigeration or ventilation and provides power for the startup of the ventilation system.

[0019] As a further illustration of the present invention, the vortex tube includes a cold air generating tube, a nozzle, an air inlet pipe, a cold end tube, a cold air chamber, a pneumatic valve, a guide vane, a vortex chamber, and a conical plug. After the cold air enters through the air inlet pipe of the vortex tube via a hose, it is accelerated and expanded through the nozzle, and the gas enters the vortex chamber along the tangential direction to form a high-speed rotating vortex. The vortex moves along the cold air generating tube. The angular velocity of the inner layer air flow is higher than that of the outer layer air flow, and the inner and outer layer air flows generate relative motion. Under the action of friction, the inner layer air flow decelerates, losing part of its kinetic energy and the temperature drops, forming a low-temperature and low-pressure air flow. The conical design of the cold air generating tube gradually reduces the cross-sectional area during the gas flow process to increase the flow rate. After being blocked by the conical plug, the inner layer low-temperature and low-pressure air flow moves back to the cold end tube. The cold end tube is also conical. By increasing the cross-sectional area of the pipe, the gas flow rate is reduced to achieve the purpose of reducing the vortex. The air flow enters the cold air chamber and converges. When the vortex gradually decreases to a certain air pressure, the pneumatic valve opens. The guide vane is used to guide the gas into the refrigeration tube, making the gas evenly distributed in the tube, while reducing the formation of vortices and ensuring the stability of the air flow to achieve the refrigeration function.

[0020] As a further illustration of the present invention, the temperature sensing device and the flow meter are respectively used to detect the temperature of the outlet air flow and the air volume flowing out.

[0021] As a further illustration of the present invention, an intelligent valve is installed at the compressed air inlet. A vane intelligent valve is installed on the middle shaft of the fan at the first-stage spiral vane. A refrigeration tube intelligent valve is installed at the inlet of the refrigeration tube. The intelligent valve, the vane intelligent valve, and the refrigeration tube intelligent valve are respectively signal-connected to the central controller.

[0022] As a further illustration of the present invention, the temperature sensing device and the gas sensing device are also respectively signal-connected to the central controller.

[0023] The present invention has the following advantages compared with the prior art:

[0024] 1. When the present invention is in use, it uses the underground compressed air as the single power source when the ventilation device starts, without using electricity or water to drive, and has no harsh requirements for water quality and water pressure, which is economical and practical.

[0025] 2. In the present invention, the temperature sensing device can self-start when the temperature reaches 30°C to avoid spontaneous combustion of coal at the return air corner, protecting the safety of underground equipment and underground construction.

[0026] 3. In the present invention, the gas sensing device can self-start when the concentration of harmful gases is too high to dilute and reduce the concentration of harmful gases, ensuring the safety of underground construction workers.

[0027] 4. The present invention adopts two-stage vanes, effectively increasing the air volume to meet the effects of cooling and reducing concentration.

[0028] 5. The energy consumption of the present invention is low, the safety factor is high, the production is simple, the coverage range is wide, and the reliability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic front sectional view of the present invention;

[0030] Figure 2 is a schematic view of the temperature sensing device of the present invention;

[0031] Figure 3 is a schematic view of the gas sensor of the present invention;

[0032] Figure 4 is a schematic sectional view of the first-stage spiral blade of the present invention;

[0033] Figure 5 is a schematic sectional view at the guide vane of the present invention;

[0034] Figure 6 is a schematic view of the flowmeter of the present invention;

[0035] Figure 7 is a sectional view of the vortex tube of the present invention;

[0036] Figure 8 is a schematic view of the vortex tube of the present invention;

[0037] Figure 9 is a schematic two-dimensional installation structure view of the vortex tube of the present invention;

[0038] Figure 10 is a schematic view of the pneumatic motor of the present invention;

[0039] Figure 11 is a front sectional view of the pneumatic motor of the present invention.

[0040] Description of the reference numerals:

[0041] In the figure: 1 - filter screen; 2 - first - stage spiral blade; 3 - lifting ring; 4 - bearing seat; 5 - temperature sensing device; 6 - flowmeter; 7 - fastening screw; 8 - retaining pin; 9 - first deflector; 10 - refrigeration pipe; 11 - intelligent valve; 12 - compressed air inlet; 13 - explosion - proof housing; 14 - sealing layer; 15 - thermal - sensitive element; 16 - temperature - sensing probe; 17 - housing; 18 - filtering component; 19 - ventilation hole group; 20 - outer wall of the fan; 21 - mounting plate; 22 - support plate; 23 - fan cavity; 24 - bearing; 25 - support rod; 26 - fan central shaft; 27 - second - stage spiral blade; 28 - blade intelligent valve; 29 - refrigeration - pipe intelligent valve; 30 - vortex tube; 31 - pneumatic motor; 32 - cold - air generating pipe; 33 - nozzle; 34 - intake pipe; 35 - cold - end pipe; 36 - cold - air chamber; 37 - air - pressure valve; 38 - deflector; 39 - vortex chamber; 40 - second deflector; 42 - tapered plug; 43 - pneumatic - motor air inlet; 44 - stator; 45 - rotor; 46 - blade; 47 - pneumatic - motor air outlet; 48 - housing; 49 - rear end cover; 50 - front end cover; 51 - bearing; 52 - exhaust - pipe shaft; 53 - bolt; 54 - air pipe. Specific embodiments

[0042] 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 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.

[0043] As Figures 1 - 11 shown, the present invention provides a technical solution: a refrigeration - pneumatic ventilation system for preventing coal spontaneous combustion and diluting gas underground, including a ventilation device, a temperature sensing device 5 and a gas sensing device. The temperature sensing device 5 is vertically suspended and installed at the return air corner of the coal - mining face, the gas sensing device is installed at the return air corner, and the ventilation device is suspended and hoisted through the lifting ring 3 in the unobstructed area of the roadway at the return air corner.

[0044] Among them, the ventilation device includes a first - stage spiral blade 2, a second - stage spiral blade 27, a refrigeration pipe 10 and a flowmeter 6. The first - stage spiral blade 2 and the second - stage spiral blade 27 are respectively installed on the fan central shaft 26 through the cooperation of a bearing seat 4, a bearing 24, a retaining pin 8 and a mounting plate 21. The refrigeration pipe 10 is a spiral coiled pipe, and the refrigeration pipe 10 is installed outside the middle section of the fan central shaft 26. The flowmeter 6 is installed in the rear - region of the second - stage spiral blade 27 in the ventilation device through a fastening screw 7.

[0045] Filter screens 1 are installed on both sides of the ventilation device, and a support rod 25 is installed at the bottom of the ventilation device. The central axis 26 of the fan is installed on the support rod 25, and a support plate 22 is also installed at the bottom of the support rod 25.

[0046] A first guide vane 9 is also installed outside the central axis 26 of the fan in the ventilation device. The first guide vane 9 does not contact the outer wall 20 of the fan. The first guide vane 9 is located between the first-stage spiral blade 2 and the second-stage spiral blade 27. By means of the first guide vane 9, the guiding and control of the air flow direction are completed, the distribution of the air flow can be optimized, eddies and turbulence can be reduced, and thus the ventilation efficiency can be improved.

[0047] A pneumatic motor 31 is also installed on the central axis 26 of the fan. The pneumatic motor 31 includes a stator 44, a rotor 45, blades 46, a housing 48, a rear end cover 49, a front end cover 50, an exhaust pipe shaft 52 and bearings 51. The stator 44 is fixed in the housing 48 to form an eccentric chamber. The rotor 45 is installed at the center inside the housing 48 through the bearings 51. Radial grooves are formed on the rotor 45, and the blades 46 are embedded in the grooves. The rotor 45 is supported by the bearings 51 and drives the central axis 26 of the fan to rotate. The air inlet 43 of the pneumatic motor is communicated with the compressed air inlet 12. Compressed air pushes the blades 46 to drive the rotor 45 to rotate. The gas is discharged through the air outlet 47 of the pneumatic motor and is communicated to the exhaust pipe shaft 52 through a trachea 54. The exhaust pipe shaft 52 penetrates through the rear end cover 49 and the front end cover 50 and is communicated with the central axis 26 of the fan. It enters the inner cavity of the central axis 26 of the fan through the exhaust pipe shaft 52 to drive the refrigeration pipe 10 to complete the cooling cycle.

[0048] Moreover, the first guide vane 9 can also be used to adjust the intensity or speed of the air flow to adapt to different ventilation requirements.

[0049] A refrigeration pipe intelligent valve 29 is installed at the inlet of the refrigeration pipe 10. A vortex tube 30 is also installed in the refrigeration pipe 10. Underground compressed air enters the central axis 26 of the fan from the compressed air inlet 12, successively passes through the first-stage spiral blade 2, the refrigeration pipe 10 and the second-stage spiral blade 27, and flows along the inner side of the central axis of the fan. Subsequently, it is guided by the guide vane 9 between the first-stage spiral blade 2 and the second-stage spiral blade 27. The first-stage spiral blade 2 is located on the inlet side of the refrigeration pipe 10, and the second-stage spiral blade 27 is located on the outlet side of the refrigeration pipe 10. After the compressed air is cooled by the refrigeration pipe 10, it is accelerated by the first-stage spiral blade 2 and the second-stage spiral blade 7 to form a directional air flow. The central axis 26 of the fan is connected to the inlet pipe 34 of the vortex tube 30 in the refrigeration pipe 10 through a hose. A second guide vane is provided at the air outlet of the refrigeration pipe 10. When the compressed gas enters the vortex tube 30 through the hose, the gas rotates in the vortex tube 30. At the same time, the gas is cooled and converted into low-temperature and low-pressure gas, enters the refrigeration pipe 10, and flows out of the refrigeration pipe 10 for refrigeration or ventilation and provides power for the start of the ventilation system.

[0050] The temperature sensing device 5 includes an explosion-proof housing 13, a sealing layer 14, a thermosensitive element 15 and a temperature sensing probe 16. The thermosensitive element 15 and the temperature sensing probe 16 form a temperature sensing component. The temperature sensing component is installed in the sealing layer 14. The explosion-proof housing 13 is wrapped outside the sealing layer 14. And the outer end of the temperature sensing probe 16 is in contact with the external environment. The temperature sensing device 5 and the flowmeter 6 are respectively used to detect the temperature of the outlet air current and the outflow air volume.

[0051] The gas sensing device includes a housing 17, a filtering component 18 and a ventilation hole group 19. The ventilation hole group 19 is installed at the front end of the housing 17. The gas concentration monitoring is completed through the ventilation hole group 19. A filtering component 18 is connected between the ventilation hole group 19 and the inner cavity of the housing 17.

[0052] The distance between the temperature sensing device 5 and the roof of the return air corner is not greater than 300 mm, and the distance from the roadway wall is not less than 200 mm. And the alarm value of the temperature sensing device 5 is set at 30 °C.

[0053] The gas sensing device is installed at a distance not greater than 800 mm from the old goaf and the roof cutting pillar at the return air corner. At the same time, the hanging position of the gas sensing device is not more than 300 mm from the roof, not less than 200 mm from the roadway rib, and not less than 1 m above the arch base line of the roadway when hanging in the arched roadway.

[0054] An intelligent valve 11 is installed at the compressed air inlet 12. A vane intelligent valve 28 is installed at the first-stage spiral vane 2 on the central shaft 26 of the fan. A refrigeration pipe intelligent valve 29 is installed at the inlet of the refrigeration pipe 10. The intelligent valve 11, the vane intelligent valve 28 and the refrigeration pipe intelligent valve 29 are respectively connected to the central controller in signal.

[0055] Underground compressed air enters from the compressed air inlet 12, and successively passes through the first-stage spiral vane 2, the refrigeration pipe 10 and the second-stage spiral vane 27 to provide power for the start of the ventilation system.

[0056] The refrigeration pipe 10 is arranged in a spiral shape behind the first-stage spiral vane 2. When the compressed air enters the refrigeration pipe 10, it will drive the refrigeration pipe 10 to start operating. A second guide vane 40 is arranged at the air outlet of the refrigeration pipe 10. The compressed gas of the vortex tube 30 entering the refrigeration pipe 10 is reversely rotated under the action of the vortex tube to be converted into cold air and flows to the outlet of the refrigeration pipe 10.

[0057] Specifically, the vortex tube 30 includes a cold air generating tube 32, a nozzle 33, an air inlet pipe 34, a cold end tube 35, a cold air chamber 36, a pneumatic valve 37, a guide vane 38, a vortex chamber 39, and a conical plug 42. After the cold air enters through the air inlet pipe 34 of the vortex tube 30, it is accelerated and expanded by the nozzle 33, and the gas enters the vortex chamber 39 along the tangential direction to form a high-speed rotating vortex. The vortex moves along the cold air generating tube 32. The angular velocity of the inner layer air flow will be higher than that of the outer layer air flow, and the inner and outer layer air flows generate relative motion. Under the action of friction, the inner layer air flow decelerates, loses part of its kinetic energy, and the temperature drops, forming a low-temperature and low-pressure air flow. The conical design of the cold air generating tube 32 gradually reduces the cross-sectional area during the gas flow process to increase the flow velocity. After being blocked by the conical plug 42, the inner layer low-temperature and low-pressure air flow moves back to the cold end tube 35. The cold end tube 35 is also conical. By increasing the cross-sectional area of the pipeline, the gas flow velocity is reduced to achieve the purpose of reducing the vortex. The air flow enters the cold air chamber 36 and converges. When the vortex gradually decreases to a certain air pressure, the pneumatic valve 37 opens, and the guide vane 38 is used to guide the gas into the refrigeration tube 10, so that the gas is evenly distributed in the tube, while reducing the formation of vortices and ensuring the stability of the air flow to achieve the refrigeration function.

[0058] The outflowing low-temperature air flow is mixed with the air flow generated by the first-stage spiral blade 2 to achieve the purpose of cooling.

[0059] When the temperature sensing device 5 detects that the temperature of the return air corner reaches 30 °C, the intelligent valve 11, the blade intelligent valve 28, and the refrigeration tube intelligent valve 29 are automatically opened. The underground compressed air enters the middle shaft 26 of the fan, driving the first-stage spiral blade 2, the refrigeration tube 10, and the second-stage spiral blade 27 to start working automatically to avoid spontaneous combustion of coal in the return air corner and protect the safety of underground equipment and underground construction.

[0060] Similarly, when the gas sensing device monitors that the concentration of any gas in the return air corner reaches the set value of the concentration of toxic and harmful gases, the set values are as follows in the table

[0061] The intelligent valve 11 and the blade intelligent valve 28 start automatically, and the blown air flow plays a role in diluting the gas to ensure the safety of underground construction workers. At the same time, when it is considered that the return air corner needs to be cooled and diluted manually, the intelligent valve 11 can also be manually opened to achieve this purpose.

[0062]

[0063]

[0064] According to the ventilation temperature reduction formula, the following ventilation volume calculation formula can be deduced:

[0065]

[0066] Wherein:

[0067] V: Ventilation volume (m 3 );

[0068] Q: Heat to be discharged (W);

[0069] t p -t j : Temperature difference before and after ventilation (K or °C);

[0070] c: Specific heat capacity of air at constant pressure (J / (kg·K));

[0071] ρ: Air density (kg / m 3 ), approximately 1.2 kg / m under standard conditions 3 .

[0072] Based on the ventilation gas volume and ventilation rate, the following ventilation calculation formula can be derived:

[0073]

[0074] Wherein:

[0075] Q: Ventilation rate (m 3 / s);

[0076] V: Mine volume (m 3 );

[0077] t: Time (s);

[0078] C target : Target concentration of harmful gas (%);

[0079] C0: Current concentration of harmful gas (%);

[0080] Example 1

[0081] Vertically suspend the temperature sensing device 5 at the return air corner of the coal mining face, install it no more than 300 mm from the roof and no less than 200 mm from the roadway wall, and set the alarm value to 30 °C.

[0082] Install the gas sensing device no more than 800 mm from the old goaf and cutting roof pillars at the return air corner. At the same time, its hanging distance from the roof does not exceed 300 mm, the distance from the roadway side is not less than 200 mm, and it is hung at a position not less than 1 m above the arch foundation line of the arched roadway. The ventilator is suspended and hoisted at the return air corner where there are no other obstacles with too close distances around the roadway, and it is installed at a relatively high position from the ground.

[0083] At the return air corner of a coal mining face in a certain mine, the temperature sensing device 5 senses that the temperature exceeds the alarm value of 30 °C. The sensor transmits the signal to the central control room. At the same time, the intelligent valve 11, the vane intelligent valve 28, and the refrigeration pipe intelligent valve 29 start automatically. The underground compressed gas enters the fan central shaft 26 through the intelligent valve 11, and drives the primary spiral vane 2 and the secondary spiral vane 27 to rotate through the vane intelligent valve 28 to generate air flow.

[0084] At the same time, the compressed air enters the refrigeration pipe 10 through the refrigeration pipe intelligent valve 29, driving the refrigeration pipe 10 to start operating. The compressed gas entering the vortex tube 30 in the refrigeration pipe 10 is reversely rotated by the action of the vortex tube 30 to become cold air and flows to the outlet of the refrigeration pipe 10. The outflowing low-temperature air flow is first mixed with the air flow generated by the primary spiral vane 2 of the fan to generate low-temperature cold air, and then further mixed through the secondary spiral vane 27. The temperature sensing device 5 and the flowmeter 6 at the outlet of the fan detect the temperature and the outflowing air volume of the outlet air flow, and control the temperature and the air volume of the outlet air flow through the above formula. Finally, the air flow reaches the position where the temperature sensing device 5 detects that the temperature at the return air corner exceeds the set value. When the detected temperature of the air flow at the return air corner drops below the alarm value, the signal is transmitted to the central control room, so that the intelligent valve 11, the vane intelligent valve 28, and the refrigeration pipe intelligent valve 29 are automatically closed, thereby achieving the purpose of cooling and controlling the occurrence of accidents.

[0085] Calculation of the required ventilation volume. Under standard atmospheric pressure and normal temperature, the air density is about 1.225 kg / m 3 ; the specific heat capacity of air is about 1005 J / (kg·K); the temperature in the mine drops by 5 °C; 20000 W of heat is generated in the mine per hour; substituting the above values into the formula:

[0086]

[0087] Embodiment 2

[0088] The temperature sensing device 5 is vertically suspended at the return air corner of the coal mining face, installed no more than 300 mm from the roof and no less than 200 mm from the roadway wall, and the alarm value is set at 30 °C.

[0089] The gas sensing device is installed no more than 800 mm from the old goaf and the cut-off pillar at the return air corner. At the same time, its hanging distance from the roof does not exceed 300 mm, and the distance from the roadway side is not less than 200 mm. In an arched roadway, it is hung at a position not less than 1 m above the roadway arch baseline. The ventilator is suspended and hoisted at the return air corner where there are no other obstacles with too close distances around the roadway, and is installed at a relatively high position from the ground.

[0090] At the return air corner of a coal mining face in a certain mine, when the gas sensor senses that the methane concentration exceeds the alarm value of 0.75%, the sensor transmits the signal to the central control room. At the same time, the intelligent valve 11 and the vane intelligent valve 28 start automatically. The underground compressed gas enters the fan central shaft 26 through the intelligent valve 11, and drives the first-stage spiral vane 2 and the second-stage spiral vane 27 to rotate through the vane intelligent valve 28 to generate air flow. The flowmeter 6 detects the air volume flowing out of the outlet. The air volume of the outlet air flow is controlled by the above formula. Finally, the air flow reaches the position where the gas sensor detects that the methane in the return air corner exceeds the set value, and the methane gas concentration in the return air corner is diluted by the air flow. When the gas sensor detects that the concentration drops below the alarm value, it transmits the signal to the central control room, so that the intelligent valve 11 and the vane intelligent valve 28 close automatically, so as to achieve the purpose of diluting toxic and harmful gases and controlling the occurrence of accidents.

[0091] Calculation of the required ventilation volume. The volume V of the mine space: 10000m 3 ; Initial harmful gas concentration C0: 0.0036%; Target harmful gas concentration C target : 0.0024; Time t: 1h = 3600s; Substitute the above values into the formula:

[0092]

[0093] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0094] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas underground, characterized in that: It comprises a ventilation device, a temperature sensing device (5) and a gas sensing device, wherein the temperature sensing device (5) is vertically suspended and installed at the return air corner of the coal mining face, the gas sensing device is installed at the return air corner, and the ventilation device is suspended and hoisted in an unobstructed area of ​​the tunnel at the return air corner through a lifting ring (3); The ventilation device comprises a primary spiral blade (2), a secondary spiral blade (27), a refrigeration pipe (10) and a flow meter (6); the primary spiral blade (2) and the secondary spiral blade (27) are respectively mounted on a fan central axis (26) in a fan chamber (23) through the cooperation of a bearing seat (4), a bearing (24), a bayonet (8) and a mounting plate (21); the refrigeration pipe (10) is a spiral coil, and the refrigeration pipe (10) is mounted on the outer side of the middle section of the fan central axis (26); the flow meter (6) is mounted in the rear area of ​​the secondary spiral blade (27) in the ventilation device through a fastening bolt (7); The temperature sensing device (5) comprises an explosion-proof housing (13), a sealing layer (14), a thermistor (15) and a temperature sensing probe (16), wherein the thermistor (15) and the temperature sensing probe (16) constitute a temperature sensing component, which is installed in the sealing layer (14), the explosion-proof housing (13) is wrapped around the outside of the sealing layer (14), and the outer end of the temperature sensing probe (16) is in contact with the external environment; The gas sensing device comprises a housing (17), a filter component (18) and a vent group (19); the vent group (19) is mounted at the front end of the housing (17); gas concentration monitoring is performed through the vent group (19); and the filter component (18) is connected between the vent group (19) and the inner cavity of the housing (17).

2. A refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas underground according to claim 1, characterized in that: The distance between the temperature sensor device (5) and the return air corner top plate is not greater than 300 mm, and the distance from the tunnel wall is not less than 200 mm, and the alarm value of the temperature sensor device (5) is set to 30°C.

3. The underground refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas according to claim 1, characterized in that: The gas sensing device is installed at the return air corner, no more than 800mm away from the old pond and the top column. At the same time, the gas sensing device is hung no more than 300mm away from the top plate and no less than 200mm away from the side of the tunnel. When hung in an arched tunnel, it is not less than 1m above the tunnel arch base line.

4. The underground refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas according to claim 1, characterized in that: Filters (1) are installed on both sides of the ventilation device, and a support rod (25) is installed at the bottom end of the ventilation device. The fan center axis (26) is installed on the support rod (25), and a support plate (22) is also installed at the bottom end of the support rod (25).

5. The underground refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas according to claim 1, characterized in that: In the ventilation device, a first guide vane (9) is also installed on the outside of the fan shaft (26). The first guide vane (9) is located between the first-stage spiral blade (2) and the second-stage spiral blade (27). The airflow direction is guided and controlled by the first guide vane (9). An air motor (31) is also installed on the fan shaft (26). The air motor air inlet (43) on the air motor (31) is connected to the compressed air inlet (12). After the compressed air drives the air motor (31) to rotate, it enters the inner cavity of the fan shaft (26) through the exhaust pipe shaft (52) of the air motor (31), and drives the refrigeration pipe (10) to complete the cooling cycle.

6. The underground refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas according to claim 1, characterized in that: A refrigeration pipe intelligent valve (29) is installed at the inlet of the refrigeration pipe (10), and a vortex tube (30) is also installed in the refrigeration pipe (10). After the compressed air in the well enters the fan shaft (26) from the compressed air inlet (12), it flows along the inner side of the fan shaft (26), and is then guided by the guide plate (9) between the first-level spiral blade (2) and the second-level spiral blade (27). After the compressed air is cooled by the refrigeration pipe (10), it is accelerated to form a directional wind flow. The fan shaft (26) and the air inlet pipe (34) of the vortex tube (30) in the refrigeration pipe (10) are connected by a hose. A second guide plate (40) is arranged at the air outlet of the refrigeration pipe (10). When the compressed gas enters the vortex tube (30) from the air inlet pipe (34) through the hose, it rotates, and the gas is cooled and converted into low-temperature and low-pressure gas, which is used for refrigeration or ventilation, and provides power for starting the ventilation system.

7. A refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas underground according to claim 6, characterized in that: The vortex tube (30) includes an air inlet pipe (34) disposed therein. After the compressed gas enters the vortex tube (30) through the air inlet pipe (34), the compressed gas is accelerated and expanded by a nozzle (33) disposed in the vortex tube (30). After the gas enters the vortex chamber (39) along a tangential direction, a high-speed rotating vortex is formed. The vortex moves along the cold air generating tube (32) to form a low-temperature and low-pressure airflow. The conical design of the cold air generating tube (32) is used to increase the flow rate. The inner layer of the low-temperature and low-pressure airflow After being blocked by the conical plug (42) in the cold air generating tube (32), the cold end tube (35) moves back to the vortex chamber (39). The airflow after the gas flow rate is reduced by the cold end tube (35) enters the cold air chamber (36) on the other side of the cold end tube (35) and converges. When the vortex gradually decreases and reaches a predetermined air pressure, the air pressure valve (37) of the cold air chamber (36) is opened, and the guide plate (38) on the other side of the cold air chamber (36) is used to guide the gas into the refrigeration tube (10) to realize the refrigeration function.

8. The underground refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas according to claim 1, characterized in that: The temperature sensing device (5) is used to detect the temperature of the outlet air flow, and the flow meter (6) is used to detect the air volume of the outlet air flow.

9. The underground refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas according to claim 5, characterized in that: An intelligent valve (11) is installed at the compressed air inlet (12), a blade intelligent valve (28) is installed at the first-stage spiral blade (2) on the central axis (26) of the fan, and a refrigeration pipe intelligent valve (29) is installed at the inlet of the refrigeration pipe (10). The intelligent valve (11), the blade intelligent valve (28) and the refrigeration pipe intelligent valve (29) are respectively connected to the central controller signal.

10. A refrigeration pneumatic ventilation system for preventing spontaneous combustion of coal and diluting gas underground according to claim 9, characterized in that: The temperature sensing device (5) and the gas sensing device are also respectively connected to the central controller for signal transmission.

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