Pneumatic conveying explosion suppression system

Abstract

The invention provides a pneumatic conveying explosion suppression system, and relates to the field of industrial explosion-proof safety. The pneumatic conveying explosion suppression system comprises a connecting pipe installed on a pneumatic conveying pipe, a sensing module, a control unit and an explosion suppression execution mechanism, and the sensing module and the explosion suppression execution mechanism are both installed on the connecting pipe; the sensing module comprises a dust concentration detector, an infrared temperature sensor and a pressure sensor, the dust concentration detector detects the mass concentration of dust in the pipeline in real time, the infrared temperature sensor is used for monitoring the dust cloud temperature change rate, and the pressure sensor is used for capturing pressure fluctuation characteristics; the control unit is used for receiving and fusing the dust concentration, the temperature gradient and the pressure fluctuation frequency and calculating the explosion risk index in real time. The dust concentration, temperature gradient and pressure fluctuation characteristics in the pipeline are monitored in real time through the multi-parameter sensing module, a grading response mechanism is adopted in the whole explosion suppression process, and multi-stage protection from risk early warning and active suppression to physical isolation is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial explosion-proof safety, in particular to a pneumatic conveying explosion suppression system. Background Art

[0002] A pneumatic conveying device utilizes airflow energy to transport granular materials along the airflow within a sealed pipeline. It is suitable for conveying non-breakable granules and powders and is widely used in industries such as foundry, chemical engineering, pharmaceuticals, and grain. The pneumatic conveying device, combined with conveying piping, spherical tees, superchargers, and booster elbows, forms a sealed conveying system. The system can be equipped with an automatic electronic control system, enabling unmanned operation or automated control with a PLC.

[0003] As an efficient and closed method of conveying powder and granular materials, pneumatic conveying is widely used in chemical, pharmaceutical, food processing and energy industries. However, the potential risk of dust explosion during its operation has always been a major hidden danger in the field of industrial safety. The triggering of a dust explosion requires the simultaneous satisfaction of five elements: combustible dust, oxygen (air), ignition source, formation of dust cloud and confined space. In a pneumatic conveying system, the friction between the high-speed airflow and the material is prone to static electricity accumulation. In addition, the dust concentration in the pipeline may reach the explosion limit (usually 20-2000g / m 3 ), once it encounters an ignition source such as a mechanical spark or an overheated surface, it can trigger a chain explosion reaction with destructive power far exceeding that of an ordinary gas explosion.

[0004] In pneumatic conveying systems, the prevention and control of dust explosions depends on real-time monitoring of risk parameters in the pipeline and rapid explosion suppression response. However, traditional explosion suppression systems mostly rely on dust concentration thresholds (such as single-point detection based on light scattering method) to judge explosion risks, which makes it difficult to fully capture explosion precursors. The false alarm rate of explosion suppression triggered by dust concentration exceeding the limit is high; and most devices adopt an "all or nothing" explosion suppression strategy (such as directly triggering isolation valves or explosion vents), lack of graded response capabilities, and rigid response mechanisms. When a dangerous signal is detected, the explosion suppression of the entire system may be directly triggered, thereby affecting normal production due to excessive response. Therefore, the explosion-proof design of the pneumatic conveying system is an important measure to ensure that the system can operate safely. The present invention provides a pneumatic conveying explosion suppression system to solve the problems raised in the above background technology. Content of the invention (I) Technical problems solved

[0005] In view of the deficiencies in the prior art, the present invention provides a pneumatic conveying explosion suppression system, which solves the problems raised by the above-mentioned background technology.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: a pneumatic conveying explosion suppression system, comprising a connecting pipe installed on a pneumatic conveying pipe, a sensor module, a control unit and an explosion suppression actuator, wherein the sensor module and the explosion suppression actuator are both installed on the connecting pipe;

[0008] The sensing module includes a dust concentration detector, an infrared temperature sensor, and a pressure sensor. The dust concentration detector detects the dust mass concentration in the pipeline in real time, the infrared temperature sensor is used to monitor the temperature change rate of the dust cloud, and the pressure sensor is used to capture the pressure fluctuation characteristics.

[0009] The control unit is used to receive and integrate the three parameters of dust concentration, temperature gradient and pressure fluctuation frequency to calculate the explosion risk index in real time;

[0010] The explosion suppression actuator includes a suppression mechanism and an isolation mechanism. The suppression mechanism includes a nitrogen nozzle arranged inside the connecting pipe, and the isolation mechanism includes a barrier valve symmetrically arranged at the end of the connecting pipe. When the control unit triggers the explosion suppression instruction, the suppression mechanism is activated first, and the isolation mechanism is additionally triggered when the conditions continue to deteriorate.

[0011] Preferably, the isolation mechanism further comprises a pressure relief pipe provided on the connecting pipe and a bursting disc provided inside the pressure relief pipe, wherein the bursting disc is a positive arch type.

[0012] Preferably, the explosion suppression actuator further includes a protective mechanism provided on the outside of the connecting pipe, and the protective mechanism includes a base layer, a reinforcement layer and an outer layer.

[0013] Preferably, the control unit includes a main control board, a signal conditioning board and a drive circuit board, the main control board coordinates the operation of each module, the signal conditioning board is used to amplify the sensor signal, and the drive circuit board is used to control the nitrogen nozzle and the barrier valve.

[0014] Preferably, the connecting pipe is further provided with an audible and visual alarm, and the driving circuit board can also control the audible and visual alarm.

[0015] Preferably, the nitrogen nozzles are provided in a plurality and arranged in an annular circumference, and the nitrogen nozzles are arranged at an angle.

[0016] Preferably, the base layer is a SiO2 aerogel layer, the reinforcement layer is a carbon fiber mesh cloth, and the outer layer is a polyimide film.

[0017] Preferably, the control unit has a built-in explosion risk index calculation model, which calculates the explosion risk index in real time.

[0018] (3) Beneficial effects

[0019] The present invention provides a pneumatic conveying explosion suppression system, which has the following beneficial effects:

[0020] 1. The system uses a multi-parameter sensor module integrated into the connecting pipe to monitor dust concentration, temperature gradient, and pressure fluctuation characteristics within the pipeline in real time. The control unit uses a weighted algorithm to fuse these three parameters to calculate the explosion risk index K. The entire explosion suppression process adopts a graded response mechanism. The three-layer composite structure of the protective mechanism effectively resists the high temperature shock and mechanical damage caused by the explosion, achieving a multi-level protection system from risk warning, active suppression, and physical isolation.

[0021] 2. Through the laser scattering method of the dust concentration detector, the three-probe temperature gradient field analysis of the infrared temperature sensor, and the high-frequency sampling and wavelet transform spectrum feature extraction of the pressure sensor, dynamic perception of the three parameters of dust, temperature, and pressure is achieved, and multi-parameter fusion monitoring is carried out to improve the warning accuracy.

[0022] 3. In the first-stage suppression, the annular nitrogen nozzle sprays high-purity nitrogen, and the inerting gas curtain covers the pipeline to suppress the initial deflagration; the barrier valve in the second-stage isolation is quickly closed, and the positive arch bursting disc is used for directional pressure relief to effectively block the spread of the explosion.

[0023] 4. A protective mechanism is set on the outer layer of the connecting pipe, which is composed of a SiO2 aerogel layer that can withstand instantaneous high temperatures of 1200°C, a carbon fiber mesh cloth 3K plain weave + epoxy resin to enhance impact resistance, and a polyimide film fluorocarbon coating for corrosion resistance to form a composite protective layer to resist explosion shock waves and high temperature damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the system structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the connecting pipe structure of the present invention;

[0026] Figure 3 The structure of the present invention Figure 3 Schematic diagram from another perspective;

[0027] Figure 4 Schematic diagram of the nozzle structure of the present invention;

[0028] Figure 5 It is a schematic structural diagram of the protection mechanism of the present invention.

[0029] Among them, 1. Sensor module; 2. Control unit; 3. Explosion suppression actuator; 4. Connecting pipe; 5. Sound and light alarm; 101. Dust concentration detector; 102. Infrared temperature sensor; 103. Pressure sensor; 201. Main control board; 202. Signal conditioning board; 203. Drive circuit board; 301. Suppression mechanism; 302. Isolation mechanism; 303. Protection mechanism; 3011. Nozzle; 3021. Isolation valve; 3022. Pressure relief pipe; 3023. Bursting disc; 3031. Base layer; 3032. Reinforcement layer; 3033. Outer layer. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] Example:

[0032] like Figure 1-5 As shown, an embodiment of the present invention provides a pneumatic conveying explosion suppression system, including a connecting pipe 4 installed on the pneumatic conveying pipe, a sensor module 1, a control unit 2 and an explosion suppression actuator 3, the sensor module 1 and the explosion suppression actuator 3 are both installed on the connecting pipe 4, the sensor module 1 includes a dust concentration detector 101, an infrared temperature sensor 102 and a pressure sensor 103, the dust concentration detector 101 detects the dust mass concentration in the pipeline in real time, the infrared temperature sensor 102 is used to monitor the temperature change rate of the dust cloud, and the pressure sensor 103 is used to capture the pressure fluctuation characteristics.

[0033] The dust concentration detector 101 uses the laser scattering principle to send concentration data to the control unit 2; it adopts a opposed laser scattering module, with the transmitting end and the receiving end embedded in the side wall of the connecting tube 4. The transmitting end integrates a semiconductor laser, and the light beam forms a parallel light spot through a collimating lens; the receiving end is equipped with a PIN photodiode array, covering a scattering angle range of 10° to 120°, and inverts the dust mass concentration through the multi-angle scattered light intensity distribution.

[0034] Three sets of infrared temperature sensors 102 are arranged along the connecting pipe 4 to monitor the temperature distribution at the center, near the pipe wall, and far away from the pipe wall, respectively, and calculate the temperature gradient field. The infrared temperature sensors 102 have built-in dual-band thermal imaging modules to monitor the temperature gradient (ΔT / Δt) of the dust cloud in real time.

[0035] The pressure sensor 103 is a high-frequency dynamic piezoelectric sensor with a sampling frequency of 10 kHz. It captures pressure fluctuation characteristics (such as steep rising edges or specific spectral components). The signal conditioning board 202 performs a wavelet transform on the pressure signal to extract the energy proportion of the high-frequency component and identify the pressure transient signal at the initial stage of deflagration.

[0036] The connecting pipe 4 is installed at the key nodes of the conveying pipeline (downstream of the elbow and the confluence point of the bifurcated pipes). The connecting pipe 4 adopts a flange connection method and a seal is set at the connection to maintain a stable connection and good sealing performance.

[0037] The control unit 2 receives and integrates three parameters: dust concentration, temperature gradient, and pressure fluctuation frequency, to calculate the explosion risk index in real time. The control unit 2 has a built-in explosion risk index calculation model, which calculates the explosion risk index in real time. The control unit 2 comprises a main control board 201, a signal conditioning board 202, and a driver circuit board 203. The main control board 201 coordinates the operation of each module, running an embedded Linux system, and coordinates signal acquisition, model calculation, and actuator control. The signal conditioning board 202 amplifies sensor signals, filtering, amplifying, and normalizing dust concentration, infrared temperature gradient, and pressure fluctuation. The driver circuit board 203 controls the nitrogen nozzle 3011 and the isolation valve 3021. The driver circuit board 203 outputs PWM pulses to drive the nitrogen nozzle and simultaneously control the isolation valve 3021. An audible and visual alarm 5 is also installed on the connecting pipe 4. The driver circuit board 203 also controls the audible and visual alarm 5. A level 1 explosion suppression command simultaneously activates the audible and visual alarm 5, emitting a high-frequency beep and red flashing warning light, prompting operator intervention.

[0038] The explosion risk index calculation model built into control unit 2 calculates the risk index K in real time using the following formula:

[0039] K=α·(C / C_LEL)+β·(ΔT / Δt)+γ·(f / f_0)

[0040] in:

[0041] C is the real-time dust concentration, C_LEL is the lower explosion limit concentration;

[0042] ΔT / Δt is the temperature change rate;

[0043] f is the pressure fluctuation frequency, f_0 is the reference frequency;

[0044] α, β, and γ are weight coefficients, and α+β+γ=1. They can be configured according to the dust type to adapt to different scenarios such as coal powder and aluminum powder (for example, coal powder: α=0.6, β=0.25, γ=0.15; aluminum powder: α=0.5, β=0.3, γ=0.2), and the main control board 201 calls the parameter library for automatic matching.

[0045] When K≥0.75, the suppression mechanism 301 is triggered, and when K≥1.1, the isolation mechanism 302 is additionally triggered.

[0046] The explosion suppression actuator 3 includes a suppression mechanism 301, an isolation mechanism 302 and a protection mechanism 303 provided on the outside of the connecting pipe 4. The suppression mechanism 301 includes a nitrogen nozzle 3011 provided inside the connecting pipe 4, and an electromagnetic valve is provided on the delivery pipe of the nitrogen nozzle 3011. The nitrogen nozzle 3011 is provided in multiple forms and arranged in a circular shape. The nitrogen nozzle 3011 is inclined, and the annular array sprays toward the center of the pipeline at an inclination angle of 30°.

[0047] When the value is ≥0.75, the signal conditioning board 202 sends a first-level explosion suppression command to the driver circuit board 203, activating the suppression mechanism 301. Nitrogen nozzles 3011 spray toward the center of the pipeline, forming a swirling inerting gas curtain. Nitrogen purity is ≥99.99%, and the number of nozzles open is controlled to ensure that the pipeline cross-section coverage rate is ≥85%. Solenoid valves are provided to control each nitrogen nozzle 3011. Depending on demand, nozzles in different locations can be prioritized or a full ring of nozzles can be activated to cover the entire pipeline cross-section.

[0048] The nitrogen nozzle 3011 is connected to the plant's PSA nitrogen generator unit through the main gas supply source of the delivery pipe, the spare high-pressure nitrogen cylinder group, and a buffer storage tank is set up to realize nitrogen delivery.

[0049] The isolation mechanism 302 includes a barrier valve 3021 symmetrically positioned at the end of the connecting pipe 4, a pressure relief pipe 3022 mounted on the connecting pipe 4, and a bursting disc 3023 located within the pressure relief pipe 3022. The bursting disc, also known as an explosion-proof disc or explosion-proof membrane, relieves pressure by rupturing the membrane, forcing the container to cease operation. The bursting disc and the clamp are two components: the bursting disc explodes and releases pressure at a specified burst pressure and temperature, while the clamp is an auxiliary component that attaches and holds the bursting disc at an appropriate location within the container. The bursting disc 3023 is a positive arch type, requiring maintenance every six months (burst pressure tolerance ±3%). The sealing surface of the barrier valve 3021 is coated with tungsten carbide to improve its erosion resistance and lifespan. When the control unit 2 triggers an explosion suppression command, the suppression mechanism 301 is activated first. If conditions continue to deteriorate, the isolation mechanism 302 is triggered, achieving multi-level control.

[0050] When K≥1.1, the driving circuit board 203 triggers the barrier valve 3021 to close quickly, cutting off the upstream and downstream connections of the pipeline, and cooperating with the bursting disc 3023 of the pressure relief pipe 3022 to rupture and release the pressure to release the explosion overpressure. The blasting pressure is set to directional discharge.

[0051] Moreover, the bursting disc 3023 is linked to the pressure sensor 103. When a large pressure peak is detected, even if the K value does not reach 1.1, pressure relief can still be triggered forcibly to achieve pressure relief protection and prevent the protective mechanism 303 from overloading.

[0052] Protective structure 303 comprises a base layer 3031, a reinforcement layer 3032, and an outer layer 3033. Base layer 3031 is a SiO2 aerogel layer produced using a supercritical drying method. It is 5 mm thick, has a porosity of ≥95%, and can withstand transient thermal shocks up to 1200°C. Reinforcement layer 3032 is a carbon fiber mesh fabric using a 3K plain weave and epoxy resin interlayer filling to maintain high tensile strength and absorb explosive shock energy. Outer layer 3033 is a polyimide film with a UL94 V-0 flame retardant rating and a corrosion-resistant fluorocarbon coating.

[0053] Working Principle: The dust concentration detector 101 detects dust concentration based on the laser scattering method. The infrared temperature sensor 102 monitors the temperature gradient field in different areas of the pipeline through three sets of axial probes. The pressure sensor 103 extracts the pressure fluctuation spectrum characteristics by high-frequency sampling combined with wavelet transform.

[0054] The control unit 2 main control board 201 integrates the three parameters and calculates the explosion risk index K in real time according to the formula K = α·(C / C_LEL)+β·(ΔT / Δt)+γ·(f / f_0). The weight coefficients α, β, and γ can be adapted according to the dust type;

[0055] Level 1 suppression K ≥ 0.75: The driver circuit board 203 activates the annular nitrogen nozzle 3011, which sprays high-purity nitrogen angularly toward the center of the pipeline, forming a swirling inerting gas curtain and synchronously triggering the sound and light alarm with a high-frequency buzzer and red flashing light. Level 2 isolation K ≥ 1.1: The barrier valve 3021 closes, and the positive arch bursting disc 3023 in the pressure relief pipe 3022 releases the overpressure explosion in a directional manner, blocking the explosion propagation chain.

[0056] A protective mechanism 303 is provided on the outer layer of the connecting pipe 4, which is composed of a composite protective layer consisting of a SiO2 aerogel layer resistant to instantaneous high temperatures of 1200°C, a carbon fiber mesh cloth 3K plain weave + epoxy resin reinforced impact resistance, and a polyimide film fluorocarbon coating for corrosion resistance to resist explosion shock waves and high temperature damage.

[0057] The system uses a multi-parameter sensor module integrated into the connecting pipe 4 to monitor dust concentration, temperature gradient, and pressure fluctuations within the pipeline in real time. The control unit 2 uses a weighted algorithm to fuse these three parameters and calculate the explosion risk index K. The entire explosion suppression process utilizes a graded response mechanism. The protective mechanism's three-layer composite structure effectively resists the high-temperature shock and mechanical damage caused by explosions, achieving a multi-level protection system from risk warning, active suppression, and physical isolation.

[0058] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A pneumatic conveying explosion suppression system, comprising a connecting pipe (4) mounted on a pneumatic conveying pipe, a sensor module (1), a control unit (2) and an explosion suppression actuator (3), characterized in that: The sensor module (1) and the explosion suppression actuator (3) are both installed on the connecting pipe (4); The sensing module (1) comprises a dust concentration detector (101), an infrared temperature sensor (102) and a pressure sensor (103); the dust concentration detector (101) detects the dust mass concentration in the pipeline in real time; the infrared temperature sensor (102) is used to monitor the temperature change rate of the dust cloud; and the pressure sensor (103) is used to capture pressure fluctuation characteristics; The control unit (2) is used to receive and fuse three parameters: dust concentration, temperature gradient, and pressure fluctuation frequency, and calculate the explosion risk index in real time; The explosion suppression actuator (3) comprises a suppression mechanism (301) and an isolation mechanism (302); the suppression mechanism (301) comprises a nitrogen nozzle (3011) arranged inside the connecting pipe (4); the isolation mechanism (302) comprises an isolation valve (3021) symmetrically arranged at the end of the connecting pipe (4); when the control unit (2) triggers an explosion suppression instruction, the suppression mechanism (301) is activated first; when the conditions continue to deteriorate, the isolation mechanism (302) is additionally triggered.

2. A pneumatic conveying explosion suppression system according to claim 1, characterized in that: The isolation mechanism (302) further comprises a pressure relief pipe (3022) provided on the connecting pipe (4) and a bursting disc (3023) provided inside the pressure relief pipe (3022); the bursting disc (3023) is of a positive arch type.

3. A pneumatic conveying explosion suppression system according to claim 2, characterized in that: The explosion suppression actuator (3) further comprises a protection mechanism (303) arranged outside the connecting pipe (4), and the protection mechanism (303) comprises a base layer (3031), a reinforcement layer (3032) and an outer layer (3033).

4. A pneumatic conveying explosion suppression system according to claim 3, characterized in that: The control unit (2) comprises a main control board (201), a signal conditioning board (202) and a driving circuit board (203); the main control board (201) coordinates the operation of each module; the signal conditioning board (202) is used to amplify sensor signals; and the driving circuit board (203) is used to control the nitrogen nozzle (3011) and the barrier valve (3021).

5. A pneumatic conveying explosion suppression system according to claim 4, characterized in that: The connecting pipe (4) is also provided with an audible and visual alarm (5), and the driving circuit board (203) can also control the audible and visual alarm (5).

6. A pneumatic conveying explosion suppression system according to claim 5, characterized in that: The nitrogen nozzles (3011) are provided in a plurality and arranged in a circular pattern, and the nitrogen nozzles (3011) are arranged at an angle.

7. A pneumatic conveying explosion suppression system according to claim 6, characterized in that: The base layer (3031) is a SiO2 aerogel layer, the reinforcement layer (3032) is a carbon fiber mesh cloth, and the outer layer (3033) is a polyimide film.

8. A pneumatic conveying explosion suppression system according to claim 7, characterized in that: The control unit (2) has a built-in explosion risk index calculation model, which calculates the explosion risk index in real time.

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