Metal dust auto-ignition detector

Abstract

The present application belongs to the field of dust explosion prevention safety technology, and particularly relates to a metal dust spontaneous combustion detector. An explosion-proof housing is internally provided with an explosion-proof accommodating cavity, and a thermal imager is fixedly arranged in the explosion-proof accommodating cavity. A thermal imaging lens of the thermal imager is used to collect external thermal radiation infrared signals through an optical viewing window assembly arranged on another end surface of the explosion-proof housing. A gas sensor probe for detecting the concentration of external environmental gas is arranged outside the explosion-proof housing. A wiring end of the gas sensor probe is electrically connected to a gas detection board fixedly arranged in the explosion-proof accommodating cavity through a sealing wire hole arranged on the explosion-proof housing. A cable leading interface is further arranged on the explosion-proof housing. The present application realizes early detection and early warning of metal dust spontaneous combustion by means of the combination of thermal imaging and gas sensing technology, and the explosion-proof structure design of the whole device can further improve the operation stability of the device.

Description

Technical Field

[0001] This invention belongs to the field of dust explosion prevention and safety technology, and specifically relates to a metal dust spontaneous combustion detector. Background Technology

[0002] High concentrations of metal dust can easily be generated in metal grinding workshops, polishing workshops, cutting areas, and dust collection systems such as dust collectors and silos. Metal dust is highly flammable and explosive, and under certain temperature conditions, it readily undergoes an exothermic oxidation reaction, potentially leading to spontaneous combustion. If spontaneous combustion triggers a dust explosion, it will cause severe casualties and property damage. Therefore, early detection and warning of metal dust spontaneous combustion are crucial.

[0003] Currently, existing industrial fire or dust spontaneous combustion detection equipment generally suffers from the following technical defects:

[0004] (1) Delayed early warning: Traditional visual monitoring equipment is mostly natural light monitoring equipment, which can only detect when spontaneous combustion produces open flames and thick smoke, and cannot detect smoldering powder at a certain depth.

[0005] (2) High false alarm rate of single detection method: Some existing detectors only use a single gas sensor or a single temperature sensor. A single gas sensor is easily affected by the complex airflow and background gas in the industrial site, resulting in false alarms; traditional point temperature sensors have a narrow coverage area and cannot cover large areas of dust accumulation.

[0006] (3) Difficult to balance gas detection sensitivity and explosion protection requirements: If the gas sensor and its core circuit are completely sealed inside the explosion-proof housing, the explosion protection requirements of the equipment are met, but external gas is difficult to enter, resulting in a decrease in detection sensitivity; if the gas sensor and its core circuit are placed outside, there is a lack of reliable explosion-proof wiring and sealing structure, which can easily lead to dust entering the equipment and causing equipment damage.

[0007] (4) Insufficient shock and explosion resistance of electronic components: In industrial environments, electronic equipment is inevitably subjected to vibration or impact, which can easily damage electronic components and affect the accuracy of testing. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention aims to provide a metal dust spontaneous combustion detector. This detector integrates thermal imaging and gas sensing technologies to achieve highly sensitive monitoring and early warning of the early dangerous state of metal dust spontaneous combustion. At the same time, the detector adopts a sealed and explosion-proof design to mitigate the impact of the external environment on the detector.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A metal dust spontaneous combustion detector includes: an explosion-proof housing with an internal explosion-proof containment cavity, one end face of which is an openable rear cover; a thermal imager fixedly installed within the explosion-proof containment cavity; the thermal imaging lens of the thermal imager is used to collect external thermal radiation infrared signals through an optical window assembly opened on the other end face of the explosion-proof housing; a gas sensor probe for detecting the concentration of external ambient gas is located outside the explosion-proof housing, the wiring terminal of the gas sensor probe being electrically connected to a gas detection board fixedly installed within the explosion-proof containment cavity through a sealed wire-passing hole opened on the explosion-proof housing; the explosion-proof housing also has a cable lead-out interface, the cable lead-out interface including: a connecting joint fixedly installed on the end face of the explosion-proof housing, the connecting joint communicating with the explosion-proof containment cavity, and an explosion-proof sealed joint being inserted into the end of the connecting joint;

[0011] Furthermore, the optical window assembly includes: a light-transmitting hole formed on the end face of the explosion-proof housing; a glass cover fixedly disposed on the outer edge of the light-transmitting hole; a cover plate fixedly disposed on the glass cover; and a central hole formed on the cover plate; and a lens disposed between the glass cover and the cover plate.

[0012] Furthermore, a gasket is provided between the mating surfaces of the glass cover and the outer edge of the light-transmitting hole;

[0013] Furthermore, a gasket is provided between the contact surface of the lens and the pressure cap;

[0014] Furthermore, the lens is made of tempered glass;

[0015] Furthermore, a joint sealing gasket is embedded between the insertion surfaces of the explosion-proof sealing joint and the connecting joint;

[0016] Furthermore, the connecting joint is made of aluminum alloy, and the explosion-proof sealing joint is made of stainless steel;

[0017] Furthermore, the explosion-proof housing includes: a housing with an opening at one end and a rear cover that is tightly fitted to the opening end of the housing by fasteners;

[0018] Furthermore, a gasket is provided at the mating surface between the housing and the rear cover;

[0019] Furthermore, the explosion-proof housing is made of aluminum alloy.

[0020] The beneficial effects of adopting the above technical solution are as follows:

[0021] (1) This detector breaks through the limitations of traditional visible light monitoring by integrating thermal imaging and gas sensing technologies to achieve early detection and warning of spontaneous combustion of metal dust. The internal thermal imaging component can accurately detect the abnormal infrared radiation emitted by smoldering dust particles with a burial depth ≥50mm and a size ≤5mm; at the same time, the external gas sensor can simultaneously monitor the trace amounts of hydrogen and carbon monoxide released by the oxidation of dust. This multi-dimensional cross-verification not only significantly advances the warning time but also effectively reduces the false alarm rate of a single sensor in complex scenarios.

[0022] (2) To address the issue that the explosion-proof enclosure might obstruct gas entry, this equipment employs a design of "exposed probe and built-in mainboard." The gas sensor probe protrudes from the outside of the enclosure, enabling it to detect ambient gases immediately; the gas detection board is housed inside the explosion-proof enclosure to ensure its safety. The two are electrically connected via a sealed wiring hole, thus ensuring both the sensitivity of detecting trace gases produced by dust combustion and maintaining the explosion-proof integrity of the equipment.

[0023] (3) The detector achieves a high level of shock absorption in its mechanical structure. The external window adopts a double-cap design to disperse and transmit external impact force to the housing; the internal thermal imaging board bracket and gas detection board bracket are set independently, cutting off the force path of external window deformation to internal precision components. Even if the external is subjected to severe vibration and impact, the internal infrared camera optical path remains stable and will not be deflected or physically damaged.

[0024] (4) In response to hazardous flammable dust environments, this equipment features a robust explosion-proof sealing system. Anti-aging silicone rubber gaskets are installed at joints such as the viewing window interlayer and shell splicing surfaces. At the weakest point in explosion-proof protection—the bottom cable outlet—a combination design of "aluminum alloy connector + connector sealing gasket + stainless steel explosion-proof sealing connector" is employed. The overall protection level is as high as IP65, enabling long-term stable operation across a wide temperature range from -30℃ to +60℃. Attached Figure Description

[0025] Figure 1 A side view of a metal dust spontaneous combustion detector provided by the present invention;

[0026] Figure 2 A cross-sectional view of a metal dust spontaneous combustion detector provided by the present invention;

[0027] Figure 3 A top view of a metal dust spontaneous combustion detector provided by the present invention;

[0028] The components include: 1. Housing; 2. Back cover; 3. Thermal imaging camera board bracket; 4. Gas detection board bracket; 5. Glass cover; 6. Lens; 7. Cover plate; 8. First gasket; 9. Second gasket; 10. Third gasket; 11. Connecting connector; 12. Connector sealing gasket; 13. Explosion-proof sealing connector; 14. Thermal imaging lens; 15. Gas sensor probe; 16. Thermal imaging camera board; 17. Gas detection board; 18. First hex socket head cap screw; 19. First Phillips head countersunk screw; 20. Second Phillips head countersunk screw; 21. Second hex socket head cap screw; 22. Third hex socket head cap screw; 23. Fourth hex socket head cap screw. Detailed Implementation

[0029] The technical solution adopted by the present invention will be clearly and completely described below with reference to the accompanying drawings and specific implementation examples.

[0030] Firstly, the metal dust spontaneous combustion detector provided by this invention is mainly used for detecting and preventing spontaneous combustion of metal dust in hazardous locations containing explosive gas mixtures and in Zone 21 and Zone 22 hazardous locations formed by a mixture of combustible dust and air. This equipment meets the requirements of protection level below IP65, explosion-proof marking of ExtaⅢCT20080℃Da, and temperature detection range of -20~550℃.

[0031] like Figure 1-3 As shown, the entire metal dust spontaneous combustion detector consists of an explosion-proof housing, an optical window assembly, a thermal imaging detection assembly, a gas detection assembly, and explosion-proof connectors and sealing assemblies, wherein:

[0032] The explosion-proof housing is a box structure with a closed explosion-proof containment cavity inside, used to protect the electronic components placed inside. In this embodiment, the explosion-proof housing includes: a housing 1 with an opening at one end and a rear cover 2 that is tightly closed to the opening end of the housing 1 by fasteners.

[0033] Preferably, in this embodiment, both the housing 1 and the rear cover 2 can be made of 6061 aluminum alloy. By utilizing the inherent properties of the metal material, the explosion-proof housing possesses excellent explosion-proof and protective characteristics as well as corrosion resistance, and is suitable for long-term operation in various special industrial locations both indoors and outdoors. The rear cover 2 can also be provided with a product nameplate, which displays information such as the product model, explosion-proof mark, applicable ambient temperature, rated voltage, and rated current of the equipment.

[0034] The optical window assembly is sealed and installed in a light-transmitting hole opened on one end face of the housing 1. In order to ensure the best shock resistance and explosion-proof isolation effect, in this embodiment, the optical window assembly includes: a light-transmitting lens 6 and a cover assembly.

[0035] Furthermore, the pressure cap assembly is a double pressure cap structure, which includes: a glass pressure cap 5 and a cover plate 7. Specifically, the glass pressure cap 5 is used to seal the light-transmitting hole opened on the end face of the housing 1. In this embodiment, the glass pressure cap 5 is square with rounded chamfers at all four corners. A second countersunk hole is opened on the glass pressure cap 5, and each second countersunk hole is fixed to the outer edge of the light-transmitting hole of the housing 1 by a second cross countersunk screw 20.

[0036] The cover plate 7 is a plate-shaped structure with a central hole. It is fixedly installed on the end face of the glass cover 5 located outside the explosion-proof housing cavity and is used to press the lens 6 onto the glass cover 5. By using the central hole of the cover plate 7 as the light-transmitting hole of the lens 6, external light can pass through the lens 6 and the glass cover 5 in sequence and enter the explosion-proof housing cavity of the explosion-proof shell.

[0037] In this embodiment, by providing three first countersunk holes arranged in a ring on the cover plate 7, each first countersunk hole is threadedly connected to the glass cover 5 by a first cross countersunk screw 19, so as to fix the cover plate 7 and the glass cover 5 and press the lens 6, thereby forming a closed optical window assembly.

[0038] Preferably, the lens 6 is made of tempered glass to further improve its safety, thermal stability and impact resistance; both the glass cover 5 and the cover plate 7 are made of ALSI304 stainless steel to provide explosion-proof and corrosion-resistant properties; the above configuration enables the optical window assembly to meet industrial explosion-proof requirements, while the double cover design can also effectively mitigate external impact forces.

[0039] A metal mesh can also be fixedly installed inside the center hole of the cover plate 7 to resist the impact of the external environment on the lens 6 in the application scenario.

[0040] The thermal imaging detection component is a thermal imager, which is fixedly installed in the explosion-proof enclosure. It is used to accurately capture the thermal radiation infrared signal generated when the external environment is abnormally heated (such as smoldering powder with a burial depth ≥50mm and a size ≤5mm) through the optical window component.

[0041] In this embodiment, the thermal imager is an existing device, which includes: a thermal imaging lens 14 for acquiring thermal radiation infrared signals and a thermal imaging camera board 16 electrically connected to the thermal imaging lens 14 and used for analyzing and processing the thermal radiation infrared signals.

[0042] Specifically, a thermal imaging camera board bracket 3 is fixedly installed inside the explosion-proof containment cavity, and a thermal imaging camera board 16 is fixedly installed on the thermal imaging camera board bracket 3. The thermal imaging lens 14 is fixed from inside the explosion-proof containment cavity to the outer edge of the light-transmitting hole of the housing 1 by a second internal hex screw 21 to ensure that the thermal imaging lens 14 will not shift due to the deformation of the external window assembly. At the same time, it ensures that the central axis of the thermal imaging lens 14 is vertically aligned with the lens 6 for installation, and the glass cover 5 is used as the cover for the thermal imaging lens 14.

[0043] Preferably, the thermal imaging camera board bracket 3 is made of ALSI304 stainless steel and is L-shaped. Its bent support surface is fixed to the inner wall of the housing 1 by a fourth hexagonal screw 23.

[0044] The gas detection component is a gas sensor, which is used to detect in real time the trace amounts of hydrogen (H2) and carbon monoxide (CO) released by the early oxidation of metal dust. In this embodiment, the gas sensor adopts existing hydrogen and carbon monoxide concentration detection sensors, and their detection concentration range can reach 0~1000ppm.

[0045] Furthermore, to achieve high sensitivity and explosion-proof safety, the present invention adopts an internal and external distributed structure design for the gas sensor, that is, the gas sensor probe 15 is placed outside the explosion-proof housing to collect the concentration signal of the corresponding gas in the external ambient air, and the gas detection board 17, which is electrically connected to the gas sensor probe 15 and is used to process and analyze the gas concentration signal collected by the gas sensor probe 15, is placed inside the explosion-proof containment cavity of the explosion-proof housing.

[0046] Specifically, a gas detection board bracket 4 is fixedly installed inside the explosion-proof cavity of the explosion-proof housing. The gas detection board bracket 4 is made of ALSI304 stainless steel and is fixed inside the explosion-proof cavity of the explosion-proof housing in the same way as the thermal imaging camera board bracket 3. In this embodiment, the gas detection board bracket 4 is fixed to the inner wall of the housing 1 by a fourth hexagonal screw 23, and the gas detection board 17 is fixed on the gas detection board bracket 4 by fasteners.

[0047] The gas sensor probe 15, which is installed outside the explosion-proof housing, has its wiring terminal electrically connected to the gas detection board 17 inside the explosion-proof containment cavity via a sealed wire hole opened on the housing 1.

[0048] Furthermore, a metal cylinder matching the number of gas sensor probes 15 is fixed on the outer wall at one end of the housing 1. Each gas sensor probe 15 is respectively installed in the corresponding metal cylinder. A metal screen is provided at the open end of the metal cylinder. That is, the metal cylinder is used to protect the gas sensor probe 15, while allowing external ambient gas to enter the metal cylinder through the metal screen so that the gas sensor probe 15 can detect the concentration of hydrogen and carbon monoxide in the air. Due to the use of rigid connection and wire sealing design, no additional flexible gasket is needed between the metal cylinder and the housing 1 to ensure reliable protection.

[0049] Preferably, in order to protect the internal wires, the sharp angles of all supports and metal structural components located inside the explosion-proof enclosure of the explosion-proof housing must be blunted and deburred.

[0050] Explosion-proof connectors and sealing components are used to ensure the airtightness of the entire metal dust spontaneous combustion detector. They are installed at the cable outlet of the explosion-proof housing and at the assembly and connection points of other components.

[0051] In this embodiment, the cable lead-out interface of the explosion-proof housing includes: a connecting connector 11 and an explosion-proof sealing connector 13; the connecting connector 11 is made of ZL102 aluminum alloy and is a tubular structure with a flange connecting plate at one end. Three mounting through holes are evenly distributed at 120 degrees on the flange of the connecting connector 11. It is connected to the rear cover 2 at the bottom of the housing 1 by a third hexagon socket screw 22. The other end of the connecting connector 11 is inserted into the explosion-proof sealing connector 13.

[0052] The explosion-proof sealing joint 13 is preferably a tubular structure made of stainless steel. It leads out the total cable including thermal imaging, gas sensor and power line through the cable lead-out interface of the explosion-proof housing. The factory default is to provide a 0.5-meter 4-core shielded wire harness, and the external G1 / 2 explosion-proof flexible hose is used for cable protection.

[0053] In this embodiment, the explosion-proof connector and sealing assembly are sealing gaskets that are clamped and arranged in the gaps of the explosion-proof housing, the optical window assembly and the explosion-proof sealing connector 13.

[0054] Specifically, it includes: a joint sealing gasket 12 and multiple sets of gaskets. The joint sealing gasket 12 and multiple sets of gaskets are all made of silicone rubber material, which has excellent properties of high temperature resistance and corrosion resistance. In this embodiment, the multiple sets of gaskets are: a first gasket 8, a second gasket 9, and a third gasket 10, wherein: the joint sealing gasket 12 is embedded between the end faces of the explosion-proof sealing joint 13 and the connecting joint 11 for insertion and mating.

[0055] The third gasket 10 is pressed and filled between the splicing surfaces of the housing 1 and the rear cover 2;

[0056] The second gasket 9 is pressed and filled between the mating surfaces of the glass cap 5 and the housing 1;

[0057] The first gasket 8 is squeezed and filled between the mating surfaces of the lens 6 and the cover plate 7.

[0058] Secondly, the working process of this invention is as follows: When the detector is running, the external gas sensor probe 15 continuously monitors the concentration of H2 and CO gas in the environment from 0 to 1000 ppm and transmits the detection data to the internal gas detection board 17 for analysis; at the same time, the thermal imaging lens 14 inside the housing 1 continuously monitors the thermal radiation state of the dust area through the lens 6 and transmits the data to the thermal imaging camera board 16 to accurately identify early smoldering dust particles with a burial depth ≥ 50 mm and a size ≤ 5 mm; when any gas sensor, thermal imager, or all three simultaneously capture abnormal fluctuations in temperature or gas concentration characteristics, the detector immediately outputs an early warning signal to the monitoring center through the cable lead-out interface at the bottom.

[0059] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A metal dust spontaneous combustion detector, characterized in that, include: An explosion-proof housing with an explosion-proof containment cavity inside, one end face of the explosion-proof housing is an openable rear cover (2), a thermal imager is fixedly installed in the explosion-proof containment cavity of the explosion-proof housing, and the thermal imaging lens (14) of the thermal imager is used to collect external thermal radiation infrared signals through an optical window assembly opened on the other end face of the explosion-proof housing. A gas sensor probe (15) for detecting the concentration of gas in the external environment is provided on the outside of the explosion-proof housing. The wiring terminal of the gas sensor probe (15) is electrically connected to the gas detection board (17) fixedly installed in the explosion-proof cavity through a sealed wire hole opened on the explosion-proof housing. The explosion-proof housing is also provided with a cable lead-out interface, which includes a connecting joint (11) fixedly installed on the end face of the explosion-proof housing. The connecting joint (11) is connected to the explosion-proof accommodating cavity, and the end of the connecting joint (11) is inserted into an explosion-proof sealing joint (13).

2. The metal dust spontaneous combustion detector according to claim 1, characterized in that, The optical window assembly includes: a light-transmitting hole opened on the end face of the explosion-proof shell, a glass cover (5) fixedly installed on the outer edge of the light-transmitting hole, a cover plate (7) fixedly installed on the glass cover (5), and a central hole opened on the cover plate (7); A lens (6) is provided between the glass cap (5) and the cover plate (7).

3. A metal dust spontaneous combustion detector according to claim 2, characterized in that, A gasket is provided between the glass cover (5) and the mating surface of the outer edge of the light-transmitting hole.

4. A metal dust spontaneous combustion detector according to claim 2, characterized in that, A gasket is provided between the mating surfaces of the lens (6) and the cover (7).

5. A metal dust spontaneous combustion detector according to claim 2, characterized in that, The lens (6) is made of tempered glass.

6. A metal dust spontaneous combustion detector according to claim 1, characterized in that, A joint sealing gasket (12) is embedded between the insertion surfaces of the explosion-proof sealing joint (13) and the connecting joint (11).

7. A metal dust spontaneous combustion detector according to claim 6, characterized in that, The connecting joint (11) is made of aluminum alloy, and the explosion-proof sealing joint (13) is made of stainless steel.

8. A metal dust spontaneous combustion detector according to claim 1, characterized in that, The explosion-proof housing includes: a housing (1) with an opening at one end and a rear cover (2) that is tightly closed to the opening end of the housing (1) by fasteners.

9. A metal dust spontaneous combustion detector according to claim 8, characterized in that, The mating surfaces of the housing (1) and the rear cover (2) are provided with gaskets.

10. A metal dust spontaneous combustion detector according to claim 8, characterized in that, The explosion-proof housing is made of aluminum alloy.

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