A fully automatic gas and dust extraction device and method for ground coal storage silos

Abstract

The present invention discloses a fully automatic gas and dust extraction device and method for a ground coal storage silo. The device comprises a silo, an identification and alarm system, a control system, an exhaust fan, and a damping hole ventilation duct device. The identification and alarm system is provided on the inner wall of the silo roof, and the damping hole ventilation duct device is provided on both sides of the silo. The damping hole ventilation duct device comprises two air ducts, each of which is evenly provided with a clamp-type bracket to secure the air ducts. The air ducts are evenly provided with damping holes, and the damping holes are installed on the damping holes. The top ends of the two air ducts are respectively connected to the exhaust fans, and the bottom ends of the air ducts are close to the bottom of the silo. The exhaust fans are fixed to the roof of the transport and maintenance workshop on the silo roof. The identification and alarm system includes a methane sensor and a dust sensor to detect the gas and dust concentrations in the silo in real time. The control system controls the operation of the local ventilator to extract and exhaust gas and dust. The present invention has a simple structure and is easy to operate. It can fully and automatically and effectively extract gas and dust from the coal storage silo, ensuring the safety of personnel and equipment.

Description

Technical Field

[0001] The invention relates to a fully automatic gas and dust extraction device and method for a ground coal storage silo, belonging to the technical field of gas and dust control. Background Art

[0002] Gas is a flammable and explosive gas with a relative density of 0.554 to air. Under standard conditions, the density of gas is 0.716 kg / m 3 , which is lighter than air. In places like coal mines, when gas leaks reach a certain concentration, they can cause suffocation due to lack of oxygen, and can also cause combustion and explosions, resulting in serious casualties and property damage. Dust also poses an explosion risk. When the dust concentration in the air reaches a certain level, it can explode when it encounters a fire source. Investigations have found that most explosions in coal mines are mixed gas and coal dust explosions, which can cause more serious explosions than single explosions. Because large quantities of coal are stored in ground coal silos, gas and coal dust accumulate in the silos, making them prone to explosions, resulting in casualties and equipment damage.

[0003] Chinese patent CN218392713U discloses a high-efficiency gas treatment device for ground coal storage bins. The device, described in this patent, uses a motor to drive a cam, which causes a rack to reciprocate horizontally. The rack drives a gear to rotate forward and backward, which in turn drives an L-shaped tube to rotate forward and backward. The L-shaped tube drives a curved hood to swing back and forth to extract gas. Simultaneously, the swinging of the curved hood drives the curved filter to rub against a brush to clean dust. However, this gas treatment device has a small extraction range and poor effectiveness. It is unable to detect gas concentrations in the bin in real time, and excessive coal dust accumulation in the bin affects the device's service life. Therefore, there is an urgent need for a fully automatic extraction device with good extraction effectiveness, a wide extraction range, and easy handling of gas and coal dust. Summary of the Invention

[0004] The present invention aims to provide a fully automatic gas and dust extraction device and method for ground coal storage silos, which has a simple structure and is easy to operate. It can fully automatically and effectively extract gas and dust from coal storage silos, reduce the concentration of gas and coal dust, and ensure the safety of personnel and equipment.

[0005] The present invention monitors the gas and dust concentration in the silo in real time by setting up an identification alarm system. When the concentration exceeds the limit, the control system is used to automatically control the operation of the exhaust fan. The exhaust fan adopts a one-pressure-in-one-extraction cycle working mode. According to the change of airflow direction, the gas and dust extraction effect is ensured and the filter is avoided from being blocked. The air volume and wind speed are adjusted with the help of the damping hole ventilation pipeline device to achieve comprehensive and efficient extraction of gas and dust in the coal bunker.

[0006] The present invention provides a fully automatic gas and dust extraction device for a ground coal storage silo, comprising a silo, an identification and alarm system, a control system, an extraction and exhaust fan, and a damping hole ventilation pipeline device;

[0007] The silo is a common container for storing coal on the ground of a coal mine. It is a cylindrical building made of reinforced concrete. An identification alarm system is provided on the inner wall of the silo roof, and damping hole ventilation pipe devices are respectively provided on both sides of the silo. The damping hole ventilation pipe device includes two air ducts, each of which is evenly provided with a clamp-type bracket to fix the air duct. The air duct is evenly provided with damping holes, and a filter is installed on the damping holes. The top ends of the two air ducts are respectively connected to exhaust fans, and the bottom ends of the air ducts are close to the bottom of the silo. The exhaust fans are fixed on the roof of the transportation and maintenance workshop on the silo roof. The damping hole ventilation pipe device can adjust the air volume and wind speed at various positions in the silo to achieve a balance between the air volume and wind speed at various positions, thereby achieving the purpose of comprehensive extraction of gas and dust.

[0008] The identification and alarm system includes a methane sensor and a dust sensor, which are installed on the top of the silo. The system detects the gas concentration and dust concentration in the silo in real time. Once the gas concentration exceeds 0.5% or the dust concentration exceeds 5g / m 3 , a signal is sent to the control system, which in turn controls the operation of the local ventilation fan to extract gas and dust.

[0009] Furthermore, methane and dust sensors were each installed 1 meter below the coal inlet, securely mounted using a suspended mounting bracket. A methane sensor and a dust sensor were placed on either side of the coal inlet, 1 meter apart, ensuring stability and safety during installation. The sensor was connected to a power source, ensuring stable voltage, and the sensor's 4-20mA signal line was connected to the PLC control system for real-time monitoring and alarming.

[0010] Furthermore, the above-mentioned methane sensor uses the GJC4 model, and the dust sensor uses the GCG1000 model. This type of sensor is easy to connect with other systems to achieve remote monitoring and control, can be used in environments where there is a risk of gas or coal dust explosion, and meets the explosion-proof requirements of coal mines.

[0011] Furthermore, the hoisting fixed bracket includes a hoisting ring, a hoisting chain, and a hoisting bracket. The structure of the hoisting bracket is a triangular bracket. One frame of the triangular bracket is arranged to fit the bottom of the silo top plate. The hoisting ring is a semicircular ring, fixed below the frame of the hoisting bracket. The bottom of the hoisting ring is connected to the hoisting chain, and the bottom of the hoisting chain is connected to the methane sensor or the dust sensor. Specifically, the various components of the hoisting fixed bracket are made of rigid materials. The hoisting ring and the hoisting bracket are installed 1m below the coal inlet with fixing bolts, and methane sensors and dust sensors are installed on both sides respectively. One end of the hoisting chain is connected to the hoisting ring, and the other end is connected to the hoisting bracket, and the methane sensor and dust sensor are connected below. During the connection process, pay attention to adjusting the height and level of the bracket to ensure its stability.

[0012] The control system includes: a CPU module, an input module, an output module, a communication module, a power module, and a bus module;

[0013] (1) The CPU module is the core module of the PLC control system, which is mainly responsible for processing input signals, executing program instructions, controlling output signals, and providing monitoring;

[0014] (2) The input module is used to detect various sensor signals, receive the concentration limit alarm signal sent by the methane sensor or dust sensor, and transmit the signal sent by the sensor to the output module;

[0015] (3) Output module: Receives the signal from the input module and converts it into a format that can be recognized by the PLC. It converts the signal processed by the PLC into a signal suitable for executing the fan operation and controls the local fan to start working;

[0016] (4) Communication module: transmits the gas concentration, wind speed, temperature, and humidity data of the silo in the PLC system to the superior control center, realizes the communication between the PLC and the local ventilator, and can also store and record the data in the server to provide support for future safety management and decision-making; the PLC control system is connected to the superior control center via wireless signals;

[0017] (5) The power module provides power support for the PLC system to ensure that the PLC system can work normally;

[0018] (6) The bus module is used to expand the number of input and output points of the PLC system and realize data transmission and coordination between different nodes. The self-sensing valve with a four-way structure can be connected to the bus module to improve system performance.

[0019] Furthermore, the exhaust fans are two flameproof local ventilators for mining use, mounted on the roof of the silo transport and maintenance workshop with bolts, and the joints are sealed with sealant. The connected air ducts extend into the silo transport and maintenance workshop and all the way to the bottom of the silo body. The fans' power cords are connected to a PLC control system to ensure proper wiring to prevent short circuits or power supply anomalies. Upon receiving a signal from the methane sensor or dust sensor, the control system outputs a command to activate the local ventilators, extracting gas and dust from the silo.

[0020] Furthermore, the air ducts are stainless steel circular ducts, each connected to two ventilators, extending downward to the bottom of the silo's main body. The joints are sealed with sealant. Secondly, the two ducts are fixed to the left and right sides of the silo's inner wall using clamp-type brackets. Several damping holes are opened on both sides of the ducts inside the silo to adjust flow and air speed.

[0021] The clamp-type bracket includes a clamp and a support structure, and the whole is made of rigid materials. The support structure is installed on the inner wall of the silo by expansion bolts, and the clamp is connected to the support structure by fixing bolts. The clamp is made of two semicircular steel belts connected by bolts, which can tightly hold the circular air duct. Its inner diameter is 578mm and its thickness is 3mm. The support structure includes a hanger, a basket nut, and a connecting piece. The hanger is a cylindrical rod structure made of high-strength round steel. The hanger is installed on the inner wall of the silo by expansion bolts. It has sufficient strength and rigidity to bear the load. The diameter of the hanger is 20mm; the basket nut is connected to the hanger and is used to adjust the length of the hanger; the connecting piece is a circular orifice plate, and the connecting rod is set at the end of the hanger and is connected to the clamp by a fixing bolt.

[0022] The damping holes are located on both sides of the air duct, and filters are installed on the damping holes to prevent coal from entering the air duct and affecting ventilation performance. The filters are evenly distributed metal wire mesh and are fixed to the damping holes with sealant. Specifically, the filters are made of stainless steel with a specification of 35 mesh, a pore size of 0.5mm, and a thickness of 0.2mm.

[0023] The present invention provides a method for using the above-mentioned ground coal storage silo gas and dust automatic extraction device, comprising the following steps:

[0024] (1) First, connect all electrical equipment of the device to the power supply. When the operation starts, the sorting and sorting silo belt transports the coal blocks to the coal inlet of the silo. When there is a large amount of coal in the silo, the gas contained in the coal accumulates on the top of the silo and adheres to the inner wall of the silo;

[0025] (2) Methane sensors and dust sensors are used to monitor gas concentration and dust in real time. When the gas concentration or dust concentration in the silo exceeds the limit, the sensor transmits an electrical signal to the PLC control system;

[0026] (3) The PLC control system converts the signal transmitted by the sensor into a signal that adapts to the operation of the fan, and then controls the exhaust fan to start working. The two local exhaust fans adopt a cycle working mode of one pressure in and one extraction;

[0027] (4) During the first hour of operation of the device, the left ventilator performs push-in ventilation, and the right ventilator performs exhaust ventilation. The airflow flows in from the damping hole on the left air duct and flows out from the damping hole on the right air duct, making the airflow rotate;

[0028] (5) When the device is turned to the second hour, the airflow direction is reversed, that is, the left ventilator is turned into exhaust ventilation, and the right ventilator is turned into pressure ventilation, so as to ensure the extraction effect of gas and dust, and avoid clogging of the filter on the damping hole;

[0029] (6) The device will work in this cycle. When the gas concentration and dust concentration are reduced to within the safe range, the device will stop running and the gas and dust will be effectively extracted, ensuring the safety of personnel and equipment.

[0030] Beneficial effects of the present invention:

[0031] (1) The methane sensor and dust sensor cooperate with the ventilator through the PLC control system. When the gas concentration or dust concentration exceeds the limit, the local ventilator is automatically started for extraction. This can effectively reduce the concentration of gas and coal dust in the silo, reduce the risk of explosion, and ensure the safety of personnel and equipment.

[0032] (2) Installing a filter can effectively prevent coal blocks from entering the air duct, thereby ensuring that ventilation performance is not affected;

[0033] (3) Two explosion-proof local ventilators for mining use, one in a compression-in and one in an extraction cycle, are used. Together with the damping ventilation holes on both sides of the air duct, the airflow can be rotated in the silo, thereby increasing the extraction range and improving the extraction effect of gas and dust, while preventing the filter on the damping hole from becoming clogged.

[0034] (4) The damping ventilation holes on both sides of the air duct can evenly adjust the flow rate and wind speed to ensure that gas and dust are fully extracted;

[0035] (5) The overall structure of the device provided by the present invention is clear, the functions of each component are clear, and the entire device can be fully automatic and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the aerodynamic performance curve of the explosion-proof local exhaust fan for mining;

[0037] Figure 2 This is a schematic diagram of the velocity of the damping vents on both sides of the air duct;

[0038] Figure 3 It is a schematic diagram of the velocity of airflow flowing out of each damping vent;

[0039] Figure 4 This is a schematic structural diagram of the fully automatic gas and dust extraction device for a ground coal storage silo according to the present invention;

[0040] Figure 5 for Figure 4 Enlarged view of part A;

[0041] Figure 6 for Figure 4 Enlarged view of part B;

[0042] Figure 7 for Figure 4 Enlarged view of part C;

[0043] Figure 8 This is the main view of the airflow direction inside the silo;

[0044] Figure 9 This is a top view of the wind flow direction inside the silo;

[0045] Figure 10 This is a top view of the clamp-type bracket.

[0046] In the figure: 1. Silo; 2. Transport and maintenance workshop on silo roof; 3. Exhaust fan; 4. Sorting and distribution silo belt; 5. Coal inlet; 6. Coal discharge port; 7. Air duct; 8. Damping hole; 9. Hoop bracket; 10. Coal block; 11. Filter; 12. Hanging rod; 13. Turnbuckle nut; 14. Connector; 15. Hoop; 16. Methane sensor; 17. Dust sensor; 18. Lifting bracket; 19. Lifting chain; 20. Lifting ring. DETAILED DESCRIPTION

[0047] The present invention is further illustrated below by way of examples, but is not limited to the following examples.

[0048] Example 1:

[0049] like Figures 1 to 10 As shown, a fully automatic gas and dust extraction device for a ground coal storage silo includes a silo 1, an identification and alarm system, a control system, an extraction and exhaust fan 3, and a damping hole ventilation pipeline device;

[0050] The silo is a common container for storing coal on the ground in coal mines. It is a cylindrical building made of reinforced concrete with a typical size of 30m in diameter and 50m in height (the main part is 35m high), with a volume of approximately 28260m 3 A coal inlet 5 is provided at the center of the top of the silo 1, an identification alarm system is provided on the inner wall of the top plate of the silo 1, and a sorting and distributing silo belt 4 is provided above the top plate; damping hole ventilation pipeline devices are provided on both sides of the silo 1, and the damping hole ventilation pipeline device includes two air ducts 7, and the air ducts 7 are evenly provided with clamp-type brackets 9 to fix the air ducts, and damping holes 8 are evenly provided on the air ducts, and filters 11 are installed on the damping holes 8; the top ends of the two air ducts 7 are respectively connected to the exhaust fans 3, and the bottom ends of the air ducts 7 are close to the bottom of the silo 1, and the exhaust fans 3 are fixed on the roof of the silo top transportation and maintenance workshop 2; the damping hole ventilation pipeline device can adjust the air volume and wind speed at each position in the silo, so that the air volume and wind speed at each position are balanced, so as to achieve the purpose of comprehensive exhaust of gas and dust;

[0051] The identification and alarm system includes a methane sensor 16 and a dust sensor 17, which are installed on the top of the silo 1. The system detects the gas concentration and dust concentration in the silo in real time. Once the gas concentration exceeds 0.5% or the dust concentration exceeds 5g / m 3 , a signal is sent to the control system, which in turn controls the operation of the local ventilation fan to extract gas and dust.

[0052] Furthermore, methane sensor 16 and dust sensor 17 are each positioned 1 meter below coal inlet 5. A hanging bracket is used to securely mount the sensors. A methane sensor and a dust sensor are placed on either side of the coal inlet, with a distance of 1 meter between the right-hand methane sensor and the left-hand dust sensor. Ensure the stability and safety of the sensors during installation. Connect the sensors to a power source and ensure stable voltage. Connect the sensor's 4-20mA signal line to a PLC control system for real-time monitoring and alarming.

[0053] Furthermore, the methane sensor 16 is of the GJC4 model, and the dust sensor 17 is of the GCG1000 model. This type of sensor is easy to connect to other systems to achieve remote monitoring and control, and can be used in environments where there is a risk of gas or coal dust explosion, meeting the explosion-proof requirements of coal mines.

[0054] Furthermore, the hanging fixed bracket includes a hanging ring 20, a hanging chain 19, and a hanging bracket 18. The hanging bracket 18 is a triangular bracket with one side frame aligned with the bottom of the silo roof. The hanging ring 20 is a semicircular ring fixed below the side frame of the hanging bracket 18. The bottom of the hanging ring 20 is connected to the hanging chain 19, and the bottom of the hanging chain 19 is connected to the methane sensor or dust sensor. Specifically, the components of the hanging fixed bracket are made of rigid materials. The hanging ring and hanging bracket are installed 1 meter below the coal inlet with fixing bolts, and the methane sensor and dust sensor are installed on both sides. The hanging chain is connected to the hanging ring at one end and to the hanging bracket at the other end. The methane sensor and dust sensor are connected below. During the connection process, pay attention to adjusting the height and level of the bracket to ensure its stability.

[0055] The control system includes: CPU module, input module, output module, communication module, power module, bus module; the PLC control system model uses Siemens S7-400 series: it has strong anti-interference ability; the number of input and output points can be flexibly increased through expansion modules to meet the connection requirements of a large number of sensors and actuators in the coal bunker; it supports multiple communication protocols and can easily communicate with the host computer, other PLCs or intelligent devices to achieve remote monitoring and centralized management. The functions of the control system are described as follows:

[0056] (1) The CPU module is the core module of the PLC, which is mainly responsible for processing input signals, executing program instructions, controlling output signals, and providing monitoring;

[0057] (2) The input module is used to detect various sensor signals, receive the concentration limit alarm signal sent by the methane sensor or dust sensor, and transmit the signal sent by the sensor to the output module;

[0058] (3) Output module: Receives the signal from the input module and converts it into a format that can be recognized by the PLC. It converts the signal processed by the PLC into a signal suitable for executing the fan operation and controls the local fan to start working;

[0059] (4) Communication module: transmits data information such as gas concentration, wind speed, temperature, humidity, etc. of the silo in the PLC system to the superior control center, realizes communication between the PLC and the local ventilator, and can also store and record the data in the server to provide support for future safety management and decision-making; the PLC control system is connected to the superior control center via wireless signals;

[0060] (5) The power module provides power support for the PLC system to ensure that the PLC system can work normally;

[0061] (6) The bus module is used to expand the number of input and output points of the PLC system and realize data transmission and coordination between different nodes. The self-sensing valve with a four-way structure can be connected to the bus module to improve system performance.

[0062] Furthermore, the exhaust fans (3) are two flameproof local ventilators for mining applications. They are mounted on the roof of the silo transport and maintenance workshop with fixed bolts, and the joints are sealed with sealant. The connected air ducts extend into the silo transport and maintenance workshop and all the way to the bottom of the silo body. The fans' power cords are connected to the PLC control system to ensure proper wiring to prevent short circuits or power supply anomalies. Upon receiving a signal from the methane sensor or dust sensor, the control system outputs a command to activate the local ventilators, extracting gas and dust from the silo.

[0063] Specifically, the model of the flameproof local ventilator for mining in the present invention is determined by the following formula:

[0064] The required ventilation volume is calculated based on factors such as the silo volume and gas outflow volume. The air volume of the selected fan should be greater than the calculated required ventilation volume, with a margin of 1.1-1.2 times.

[0065]

[0066] In the formula: V is the volume of the silo; m is the number of ventilation times per hour; 2 refers to two air ducts; 60 refers to 60 minutes; the above formula represents the air volume required per minute for each air duct.

[0067] Furthermore, the friction resistance and local resistance of the air duct are calculated using relevant formulas of fluid mechanics. The wind pressure of the fan must be greater than the total resistance of the ventilation system, and a margin of 1.2-1.3 times is usually considered.

[0068]

[0069] Where: l—the length of the air duct;

[0070] d—pipe diameter;

[0071] v—wind speed;

[0072] g—acceleration due to gravity;

[0073] h f — frictional resistance;

[0074] λ—friction resistance coefficient.

[0075]

[0076] Where: Re—Reynolds coefficient;

[0077] ν—Kinematic viscosity of air, which is about 1.46×10 -5 m 2 / s.

[0078]

[0079] Where: h j — local resistance;

[0080] ε—local resistance coefficient.

[0081] Specifically, under normal circumstances, the ground coal storage silo is ventilated once an hour. Taking m as 1, the minimum ventilation volume required by a ventilator is about 188.4m 3 / min; calculated by the above formula, the total resistance of the ventilation system is approximately 831Pa.

[0082] The selected mining explosion-proof local ventilation fan is FBD-No.5.0 / 2×7.5.

[0083] Furthermore, the air volume of FBD-No.5.0 / 2×7.5 explosion-proof local ventilation fan for mining is 240-170m 3 / min, full pressure of 360-3280Pa, power of 2×7.5kW, full pressure efficiency ≥75%, noise ≤30dB. It can be seen that the selection of FBD-No.5.0 / 2×7.5 mining flameproof local ventilation fan can meet the required air volume and air pressure requirements, as well as the requirements for flameproof performance, noise and power during operation. Figure 1 It can be seen that the aerodynamic performance curve of FBD-No.5.0 / 2×7.5 mining flameproof local ventilation fan.

[0084] Furthermore, the air ducts 7 are stainless steel circular ducts, each connected to the two ventilators, extending downward to the bottom of the silo body. The joints are sealed with sealant. Secondly, the two ducts are fixed to the left and right sides of the silo's inner wall using clamp-type brackets. Several damping holes are opened on both sides of the ducts inside the silo to adjust the flow rate and air speed.

[0085] Furthermore, the above-mentioned air duct size is determined by the following formula:

[0086] Q=πr 2 v

[0087] Specifically, the appropriate ventilation speed is about 10-15m / s. Through calculation, a stainless steel circular air duct with a diameter of 576mm and a thickness of 2mm can be selected.

[0088] The clamp-type bracket 9 includes a clamp 15 and a support structure, and the whole is made of rigid material. The support structure is installed on the inner wall of the silo by expansion bolts, and the clamp 15 is connected to the support structure by fixing bolts. The clamp is made of two semicircular steel belts connected by bolts, which can tightly hold the circular air duct. Its inner diameter is 578mm and its thickness is 3mm. The support structure includes a hanger 12, a basket nut 13, and a connector 14. The hanger 12 is a cylindrical rod structure made of high-strength round steel. The hanger 12 is installed on the inner wall of the silo by expansion bolts. It has sufficient strength and rigidity to bear the load. The diameter of the hanger is 20mm; the basket nut 13 is connected to the hanger 12 and is used to adjust the length of the hanger; the connector 14 is a circular orifice plate, and the connecting rod is set at the end of the hanger and is connected to the clamp by fixing bolts.

[0089] The damping holes 8 are provided on both sides of the air duct, and filters 11 are installed on the damping holes to prevent coal lumps 10 from entering the air duct and affecting the ventilation performance. Furthermore, the size of the damping holes is determined by the following formula combined with CFD software simulation calculation:

[0090] Using the continuity equation:

[0091] Q=vA

[0092] Where: Q—flow rate; v—flow velocity; A—pipe cross-sectional area.

[0093] Furthermore, according to Poiseuille's law, for laminar flow in a circular tube, the relationship between flow rate and pressure difference is:

[0094]

[0095] Where: r—pipe radius;

[0096] △p—pressure difference between the two ends of the pipeline;

[0097] μ—fluid viscosity;

[0098] L—Pipeline length.

[0099] Furthermore, for the damping orifice, it can be assumed that its flow formula is:

[0100]

[0101] Where: C d —Flow coefficient of damping orifice; A d —area of ​​damping hole; ρ—fluid density.

[0102] Furthermore, in order to achieve equal flow regulation, the pipeline flow Q can be made equal to the sum of the flow rates of all damping holes:

[0103] Q=nQ d

[0104] Where: n—number of damping holes.

[0105] Furthermore, the expression for the damping hole area can be derived:

[0106]

[0107] A d =πr 2

[0108] Furthermore, by combining the above formula and trying different numbers of damping holes and flow coefficients, the range of damping hole diameters can be estimated, and simulation calculations can be performed using CFD software.

[0109] Specifically, the range of values ​​of the damping hole diameter under the above conditions was initially calculated using a formula. Then, CFD software was used for three-dimensional simulation calculations. First, a circular stainless steel air duct with a diameter of 576mm and a height of 40m was established. Damping ventilation holes were opened from high to low on both sides of the air duct at a height of 35m, with two holes opened every 1.5m from the center of the holes. The initial diameter of the damping ventilation holes is 60mm, and the diameter increases by 2mm each time according to the principle of increasing in sequence. 24 damping ventilation holes were opened on one side from high to low, and a total of 48 damping ventilation holes were opened in one air duct (two were set at the center of the holes on the same horizontal line). The diameter of the last two damping ventilation holes was 106mm; secondly, a laminar flow physical field was added, the fluid properties were set to air, and a fan was added to the top of the air duct with a fan volume of 300m 3 / min, the wind direction is downward, and 48 damping ventilation holes are set as wind outlets; finally, the speed of the wind flowing out of the holes after overcoming friction resistance and local resistance is simulated and calculated, such as Figure 2 shown.

[0110] The above calculation results are as follows Figure 3 As shown, Figure 3 Schematic diagram of the speed of air flowing out of each damping vent. Figure 3 The results show that the maximum and average velocities of the airflow flowing out of the left and right holes have similar trends and magnitudes. When the airflow flows out of the damping holes, the average velocity fluctuates between 5 and 6 m / s, and the maximum velocity fluctuates between 10 and 13 m / s, with no significant changes in either velocity. This demonstrates that the damping vents achieve the goal of regulating air speed and flow.

[0111] Based on the above calculations, damping ventilation holes were added to the main silo duct, starting with a diameter of 60mm and increasing in 2mm increments. These holes were spaced 1.5m apart from each other, starting from the highest point. Twenty-four damping holes were added to one side of the duct, for a total of 96 across the two ducts. The diameter of the four damping holes at the bottom was 106mm.

[0112] The filter is a uniformly distributed metal wire mesh that is fixed to the damping hole with sealant to prevent coal from entering the ventilation duct and affecting ventilation performance. Specifically, the filter is made of stainless steel with a specification of 35 mesh, a pore size of 0.5mm, and a thickness of 0.2mm.

[0113] The present invention provides a method for using the above-mentioned ground coal storage silo gas and dust automatic extraction device, which is carried out according to the following steps:

[0114] (1) First, install all equipment and instruments in the preset position and turn on the power. During normal operation, the sorting and distribution belt 4 transports the coal blocks 10 to the coal inlet 5 of the silo 1. A large number of coal blocks 10 fall into the silo 1 from the coal inlet 5. When they fall to the bottom of the silo 1, the coal blocks 10 break and produce fine coal dust. When there are a large number of coal blocks 10 in the silo, the gas contained in the coal will accumulate on the top of the silo 1 and adhere to the inner wall of the silo 1. As the operation progresses, a sufficient concentration of gas and coal dust will accumulate in the silo 1, which is prone to explosion accidents;

[0115] (2) The methane sensor 16 and dust sensor 17 installed on the top plate of the silo 1 can effectively monitor the changes in the gas concentration and dust concentration in the silo 1. Once the gas concentration exceeds 0.5% or the dust concentration exceeds 5g / m 3 The methane sensor 16 or the dust sensor 17 transmits an electrical signal to the PLC control system, and the PLC control system transmits data information such as the gas concentration in the silo 1 to the monitoring and detection system.

[0116] (3) The PLC control system converts the signal transmitted by the methane sensor 16 or the dust sensor 17 into a signal adapted to the operation of the exhaust fan 3, and then controls the two local ventilators 3 to start operation. The two local ventilators adopt a cycle working mode of one compression and one extraction.

[0117] (4) During the first hour of operation of the device, the left exhaust fan 3 performs forced ventilation, and the right exhaust fan 3 performs exhaust ventilation. The air flows in from the damping hole 8 on the left air duct 7 and flows out from the damping hole 8 on the right air duct 7, so that the air flow is in a rotating form, and most of the air flow flows along the inner wall of the silo 1, and only a small part of the air flow flows in the internal space of the silo 1, ensuring the exhaust effect of gas and coal dust attached to the inner wall of the silo.

[0118] (5) When the device turns to the second hour, the direction of the airflow is reversed, that is, the left exhaust fan 3 is changed to exhaust ventilation, and the right exhaust fan 3 is changed to pressure ventilation, so that the exhaust effect of gas and dust can be guaranteed, and at the same time, the filter 11 on the damping hole 8 is prevented from being blocked.

[0119] (6) The device operates in this way, and the extracted gas and dust are discharged into the atmosphere. When the gas concentration in silo 1 drops to a safe range, the device stops operating, and the gas and dust are effectively extracted, ensuring the safety of personnel and equipment.

Claims

1. A fully automatic gas and dust extraction device for ground coal storage silos, characterized by: It includes a silo, an identification and alarm system, a control system, an exhaust fan, and a damping hole ventilation duct device; an identification and alarm system is installed on the inner wall of the silo roof, and damping hole ventilation duct devices are installed on both sides of the silo. The damping hole ventilation duct device includes two air ducts, and the air ducts are evenly provided with clamp-type brackets to fix the air ducts. The air ducts are evenly provided with damping holes, and filters are installed on the damping holes; the top ends of the two air ducts are respectively connected to the exhaust fans, and the bottom ends of the air ducts are close to the bottom of the silo. The exhaust fans are fixed on the roof of the transportation and maintenance workshop on the silo roof; the identification and alarm system includes a methane sensor and a dust sensor, which are installed on the top of the silo. The system detects the gas concentration and dust concentration in the silo in real time. If the gas concentration exceeds 0.5% or the dust concentration exceeds 5g / m 3 , then send a signal to the control system, the control system includes: CPU module, input module, output module, communication module, power module, bus module, the exhaust fans are two mining explosion-proof local ventilation fans, control the operation of the local ventilation fans to extract gas and dust, the two local ventilation fans adopt a one-pressure-in and one-extraction cycle working mode; The methane sensor and dust sensor are respectively set at a position 1m below the coal inlet, and the sensors are firmly installed using a hoisting fixed bracket. The methane sensor and dust sensor are respectively set on both sides of the coal inlet, and the distance between the methane sensor and the dust sensor is 1m. The sensor is connected to the power supply and the voltage is ensured to be stable. The 4-20mA signal line of the sensor is connected to the control system to realize real-time monitoring and alarm functions; the hoisting fixed bracket includes a hoisting ring, a hoisting chain, and a hoisting bracket. The structure of the hoisting bracket is a triangular bracket. One frame of the triangular bracket is set to fit the bottom of the silo top plate. The hoisting ring is a semicircular ring, which is fixed below the frame of the hoisting bracket. The bottom of the hoisting ring is connected to the hoisting chain, and the bottom of the hoisting chain is connected to the methane sensor or the dust sensor. Several damping holes of different diameters are opened on both sides of the air duct to adjust the flow and wind speed; the initial diameter of the damping hole is 60mm, and according to the principle of increasing in sequence, the diameter of two adjacent damping holes increases by 2mm each time from top to bottom.

2. The fully automatic gas and dust extraction device for ground coal storage silos according to claim 1 is characterized by: The methane sensor uses the GJC4 model and the dust sensor uses the GCG1000 model to achieve remote monitoring and control.

3. The fully automatic gas and dust extraction device for ground coal storage silos according to claim 1 is characterized by: The exhaust fans are respectively installed on the roof of the warehouse top transport and maintenance workshop by fixing bolts, the joints are sealed with sealant, and the power cord of the ventilator is connected to the control system.

4. The fully automatic gas and dust extraction device for ground coal storage silos according to claim 1 is characterized by: The air ducts are stainless steel circular air ducts, and the two air ducts are respectively connected to the two ventilators and extend downward to the bottom of the main part of the silo. The joints are sealed with sealant. The two air ducts are fixedly installed on the left and right sides of the inner wall of the silo using a clamp-type bracket, and a filter is installed on the damping hole to prevent coal blocks from entering the air duct and affecting the ventilation performance. The filter is a uniformly distributed metal wire mesh, which is fixedly installed on the damping hole with sealant.

5. The fully automatic gas and dust extraction device for ground coal storage silos according to claim 4 is characterized by: The clamp-type bracket includes a clamp and a support structure, which are made of rigid materials; the clamp is made of two semicircular steel belts connected by bolts; the support structure includes a hanger, a basket nut, and a connecting piece. The hanger is a cylindrical rod structure made of high-strength round steel, and the hanger is installed on the inner wall of the silo through expansion bolts. The basket nut is connected to the hanger and is used to adjust the length of the hanger; the connecting piece is a circular orifice plate, and the connecting rod is arranged at the end of the hanger and is connected to the clamp by a fixing bolt.

6. The fully automatic gas and dust extraction device for ground coal storage silos according to claim 4 is characterized by: The diameter of the air duct is 576mm, the thickness is 2mm, and the height is 40m; each air duct has 24 damping holes on one side from top to bottom, and a total of 48 damping holes are set on both sides of an air duct. Two damping holes are set at the center of the same horizontal hole on an air duct, and the upper and lower spacing between two adjacent damping holes is 1.5m.

7. The fully automatic gas and dust extraction device for ground coal storage silos according to claim 4 is characterized by: The filter is made of stainless steel with a pore size of 0.5mm and a thickness of 0.2mm.

8. A method for using the fully automatic gas and dust extraction device for a ground coal storage silo according to any one of claims 1 to 7, characterized in that The following steps are involved: (1) First, connect all electrical equipment of the device to the power supply. When the operation starts, the silo belt transports the coal blocks to the coal inlet of the silo. When there is a large amount of coal in the silo, the gas contained in the coal accumulates on the top of the silo and adheres to the inner wall of the silo; (2) Methane sensors and dust sensors are used to monitor gas concentration and dust in real time. When the gas concentration or dust concentration in the silo exceeds the limit, the sensor transmits an electrical signal to the PLC control system; (3) The control system converts the signal transmitted by the sensor into a signal that adapts to the operation of the fan, and then controls the exhaust fan to start working. The two local ventilation fans adopt a cycle working mode of one pressure in and one extraction; (4) During the first hour of operation, the left ventilator performs forced ventilation, and the right ventilator performs exhaust ventilation. The airflow flows in from the damping hole on the left duct and flows out from the damping hole on the right duct, making the airflow rotate. (5) When the device turns to the second hour, the airflow direction is reversed, that is, the left ventilator becomes exhaust ventilation, and the right ventilator becomes pressure ventilation, so that the exhaust effect of gas and dust can be guaranteed, and the filter on the damping hole can be prevented from being blocked; (6) The device will work in this cycle. When the gas concentration and dust concentration are reduced to within the safe range, the device will stop running and the gas and dust will be effectively extracted, ensuring the safety of personnel and equipment.

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