Advanced fire early warning method and system based on pyrolysis particle detection

Abstract

The invention relates to the technical field of power grid operation and maintenance, in particular to an advanced fire early warning method and system based on pyrolysis particle detection, and the method comprises the following steps: setting a cloud chamber and a detector; acquiring the number of background particles in the monitoring area; arranging an air suction pipe network at the top of the monitoring area; gas at the top of the monitoring area is sucked through the gas suction pipe network and enters the cloud chamber; and the cloud chamber is humidified and depressurized. According to the embodiment of the invention, the fire situation of the monitoring area is monitored by acquiring the number of the particles in the air in the monitoring area in real time, when the combustible materials in the monitoring area reach the thermal collapse point, the cloud chamber and the detector can accurately and quickly capture that the combustible materials in the current monitoring area reach the thermal collapse point, and the fire situation of the monitoring area is monitored. Therefore, the operator can quickly respond when the monitored area is in the extremely early stage of the fire, a large amount of time is reserved for the reaction of the operator, and the effectiveness and timeliness of the fire early warning of the monitored area are remarkably improved.

Description

Technical Field

[0001] The present application relates to the technical field of power grid operation and maintenance, and in particular to an advanced fire warning method and system based on pyrolysis particle detection. Background Art

[0002] There are a large number of electrical equipment installed in the electrical room of the distribution network. During their operation, high temperatures are easily generated, which increases the fire risk factor of the electrical room.

[0003] In the prior art, the electrical room is generally monitored by a smoke alarm. When the components in the electrical room are burned due to high temperature, smoke will be generated, and the smoke alarm installed on the top of the electrical room will sound an alarm. This method has a slow early warning speed for fires. When such detectors sound an alarm, the fire on site has already developed to a certain scale, leaving little time for operators to react.

[0004] Therefore, there is a need for an advanced fire warning method and a supporting system that can achieve early warning. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present application provides an advanced fire warning method and system based on pyrolysis particle detection. The embodiment of the present application monitors the fire situation in the monitoring area by acquiring the number of particles in the air in the monitoring area in real time. When the combustibles in the monitoring area reach the thermal collapse point, the cloud chamber and the detector can accurately and quickly capture the presence of combustibles reaching the thermal collapse point in the current monitoring area, so that the operator can respond quickly when the fire in the monitoring area is in the very early stage, and a lot of time is left for the operator to respond, which significantly improves the effectiveness and timeliness of the fire warning in the monitoring area.

[0006] The above application objectives of this application are achieved through the following technical solutions: An advanced fire warning method based on pyrolysis particle detection comprises the following steps: Set up the cloud chamber and detectors; Get the number of background particles in the monitoring area; Lay out a suction pipe network at the top of the monitoring area; The gas at the top of the monitoring area is sucked into the cloud chamber through the suction pipe network; Humidification and depressurization of the cloud chamber; Get the current number of particles in the cloud chamber; Compare the current number of particles in the monitoring area with the number of background particles; Determine whether there is a fire risk in the monitored area based on the comparison results.

[0007] Optionally, obtaining the number of background particles in the monitoring area includes: Set up a number of sampling points within the monitoring area; Extract the top air of several sampling points respectively, and draw the top air of the aforementioned sampling points into the cloud chamber; The cloud chamber is humidified and depressurized to make the particles in the top air of the sampling point visible in the cloud chamber; Count the number of condensation nuclei in the cloud chamber; The number of particles in the top air of several sampling points is weighted averaged to obtain the number of background particles in the monitoring area.

[0008] Optionally, the following steps are also included: Divide the monitoring area into several zones; Get the number of background particles in each partition; A suction pipe network is laid out in each partition; The cloud chamber and detector independently detect the number of particles in the current gas in each partition; Determine whether there is a fire risk in each partition based on the current number of particles in the gas in each partition.

[0009] Optionally, the following steps are also included: When the number of particles in a partition exceeds the number of background particles, an infrared detection image of the partition is obtained; Based on the current number of particles in the partition and the current infrared detection image, it is determined whether the partition has a fire risk.

[0010] Optionally, judging whether there is a fire risk in the partition based on the current number of particles in the partition and the current infrared detection image includes: Get the type of combustible material and the thermal collapse temperature of the combustible material in the current partition; Get the distribution areas of several types of combustible materials in the current zone; Based on the current infrared detection image of the partition, the current temperature of each combustible material distribution area is obtained; Determine whether the current temperature of each distribution area exceeds the thermal collapse temperature of the combustible material in its distribution area.

[0011] Optionally, the following steps are also included: When the number of particles in the partition exceeds the number of background particles, the position information of the distribution area whose temperature exceeds the thermal breakdown temperature of the combustible material in the area is obtained.

[0012] The embodiment of the present application also provides an advanced fire warning system based on pyrolysis particle detection, which also includes the following steps: A cloud chamber, used to visualize particles in the gas in the monitoring area entering the cloud chamber; A detector for counting particles in the gas entering the cloud chamber; The suction pipe network is used to absorb the gas at the top of the monitoring area and send the top gas to the cloud chamber; Infrared detector, used to detect the temperature information of each part in the monitoring area and form an infrared image of the temperature of the monitoring area; The processing unit is used to connect with the cloud chamber, the detector and the air intake pipe network signals to control the working status of the cloud chamber, the detector and the air intake pipe network.

[0013] Optionally, the intake pipe network includes a vertical intake pipe vertically arranged on the top of the equipment and a horizontal intake pipe horizontally arranged on the top of the equipment, and a bent pipe is installed between the top of the vertical intake pipe and one end of the horizontal intake pipe, and both ends of the bent pipe are respectively connected to the vertical intake pipe and the horizontal intake pipe.

[0014] Optionally, a plurality of sampling holes are provided at the bottom of the horizontal suction pipe, the end of the horizontal suction pipe is connected to the cloud chamber, and an end hole is provided on the outer side of the end of the horizontal suction pipe.

[0015] In summary, this application has the following beneficial technical effects: The embodiment of the present application monitors the fire situation in the monitoring area by acquiring the number of particles in the air in the monitoring area in real time. When the combustibles in the monitoring area reach the thermal collapse point, the cloud chamber and the detector can accurately and quickly capture the presence of combustibles reaching the thermal collapse point in the current monitoring area, so that the operating personnel can respond quickly when the fire in the monitoring area is in the very early stage, and a lot of time is left for the operator's response, which significantly improves the effectiveness and timeliness of the fire warning in the monitoring area.

[0016] The embodiment of the present application captures and counts particles in the air by adopting a cloud chamber. When combustibles reach the thermal breakdown temperature in the monitoring area, the diameters of the thermal decomposition particles released are different. After entering the cloud chamber, the thermal decomposition particles with initial velocity and kinetic energy move in the supersaturated steam in the cloud chamber. Small droplets will gradually wrap up the thermal decomposition particles, so that the thermal decomposition particles of different diameters form condensation nuclei with consistent diameters, which makes it convenient for the detector to count the number of particles in the air and improves the accuracy of detecting the number of particles in the air.

[0017] The embodiment of the present application detects and alarms fires by counting the number of thermal decomposition particles instead of judging whether there is smoke. The current state of the monitoring area is comprehensively judged based on the number of background particles and the current number of particles in the monitoring area. The difference between the number of background particles and the number of particles in the very early stage of the fire is large, which makes the cloud chamber detector extremely accurate and reliable in detecting the very early stage of the fire, and will not cause false alarms due to the influence of dust, fog, dry ice, water vapor, high temperature and high humidity, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a detection schematic diagram of an implementation method of the present application; Figure 2 It is a schematic diagram of an air intake network according to an embodiment of the present application. DETAILED DESCRIPTION

[0019] The following is combined with Figure 1 and Figure 2 This application is described in further detail.

[0020] The present application embodiment provides an advanced fire warning method based on pyrolysis particle detection, comprising the following steps: S101, setting a cloud chamber for visualizing particles in the gas and a detector for counting the number of condensation nuclei in the cloud chamber; S102, obtaining the number of background particles inside the gas in the monitoring area under normal working conditions; S103, laying an air intake pipe network at the top of the monitoring area to absorb air from the top of the monitoring area; S104, sucking the gas at the top of the monitoring area through the suction pipe network and letting it enter the cloud chamber; S105, closing the cloud chamber, and humidifying and reducing the pressure in the cloud chamber; S106, obtaining the current number of particles in the cloud chamber through a detector; S107, comparing the current number of particles in the monitoring area with the number of background particles; S108. Determine whether there is a fire risk in the monitored area based on the comparison results.

[0021] The following is a further introduction based on specific usage scenarios.

[0022] First, step S101 is performed, in which a cloud chamber for visualizing particles in the gas and a detector for counting the number of condensation nuclei in the cloud chamber are set in the monitoring area to be monitored. When the gas enters the cloud chamber, the cloud chamber is humidified and depressurized. Different particles in the gas will form condensation nuclei with approximately equal diameters in the cloud chamber, and the detector can count the condensation nuclei in the cloud chamber. Then, step S102 is performed to obtain the number of background particles in the gas in the monitoring area under normal working conditions. Specifically, the number of background particles in the gas in the monitoring area under normal working conditions can be obtained by the following steps: First, several sampling points are set up in the monitoring area, and the sampling points are located at the top of the monitoring area; Then, the air from several sampling points is extracted respectively, and the air from the aforementioned sampling points is pumped into the cloud chamber; The cloud chamber is closed and humidified and depressurized, so that the particles in the top air of the sampling point condense with the small droplets of supersaturated steam in the cloud chamber to form condensation nuclei, thereby realizing the visualization of the particles in the air at the sampling point; Use detectors to count the number of condensation nuclei in the cloud chamber; The number of particles in the top layer of air at several sampling points is weighted averaged to obtain the number of background particles in the monitoring area. Under normal conditions, the number of invisible particles floating in the air is only about 20,000 / cc, and in high dust falling areas it is only about 25,000 / cc to 30,000 / cc, which also corresponds to the aforementioned number of background particles; In step S103, an air intake pipe network for extracting air from the top of the monitoring area is arranged at the top of the monitoring area, so that the air intake pipe network can smoothly extract air from the top of the monitoring area; Then, step S104 is executed to absorb the gas at the top of the current monitoring area through the air suction pipe network and let it enter the cloud chamber; Then, step S105 is executed to close the cloud chamber, and humidify and reduce the pressure of the cloud chamber, so that supersaturated steam is formed in the cloud chamber, so that particles in the ambient air of the current monitoring area entering the cloud chamber form condensation nuclei and thus become visible; It should be understood that the equipment in the monitoring area needs to go through several stages from normal state to fire, namely, the temperature rise stage, the thermal collapse stage and the fire ignition stage. The temperature rise stage is the stage when the combustibles in the equipment are heated from the normal working temperature to the thermal collapse point of the combustibles. The thermal collapse stage is the stage when the combustibles in the equipment continue to heat up on the basis of the thermal collapse point temperature. The fire ignition stage is the stage when the combustibles in the equipment reach the ignition point and start to ignite. In the prior art, the working status of the equipment is monitored by using a smoke alarm. The detection range of the smoke alarm is generally near the ignition point of the combustible. When the smoke alarm sounds an alarm, the combustible fire in the monitoring area is on the verge of ignition or has already ignited. In this way, the reaction time left for the operator is extremely limited. When the combustibles in the monitoring area first reach the thermal collapse stage, that is, at the very early stage of the fire, a large number of thermal decomposition particles will be released to form invisible smoke. The number of invisible particles in the air can reach 500,000 / cc to 1,000,000 / cc in a short period of time. The diameter of the aforementioned thermal decomposition particles is between 0.002 microns and 20 microns. It is difficult for existing smoke alarms to alarm for these thermal decomposition particles. In the very early stage of the fire, the gas in the monitoring area is sent to the cloud chamber. After the cloud chamber is closed, the particles in the gas contact with the supersaturated steam in the cloud chamber to form a number of condensation nuclei. The diameters of the aforementioned condensation nuclei tend to be consistent, that is, the diameters of the condensation nuclei formed by the thermal decomposition particles of different sizes produced by the thermal decomposition of the combustibles in the cloud chamber tend to be consistent; Then, step S106 is performed to obtain the current number of particles in the cloud chamber through the detector. The method in which the detector detects the number of condensation nuclei in the cloud chamber can be realized by photoelectric technology; In step S107, the current number of particles in the monitoring area is compared with the number of background particles to determine whether the current number of particles in the monitoring area is the same as the number of background particles; Finally, step S108 is executed to determine whether there is a fire risk in the monitoring area based on the comparison results. When the current particle number in the monitoring area exceeds the background particle number, it is determined that the monitoring area is in a very early stage of fire.

[0023] It can be found that the embodiment of the present application monitors the fire situation in the monitoring area by acquiring the number of particles in the air in the monitoring area in real time. When the combustibles in the monitoring area reach the thermal collapse point, the cloud chamber and the detector can accurately and quickly capture the presence of combustibles reaching the thermal collapse point in the current monitoring area, so that the operator can respond quickly when the fire in the monitoring area is in the very early stage, and a lot of time is left for the operator's response, which significantly improves the effectiveness and timeliness of fire warnings in the monitoring area.

[0024] The embodiment of the present application captures and counts particles in the air by adopting a cloud chamber. When combustibles reach the thermal breakdown temperature in the monitoring area, the diameters of the thermal decomposition particles released are different. After entering the cloud chamber, the thermal decomposition particles with initial velocity and kinetic energy move in the supersaturated steam in the cloud chamber. Small droplets will gradually wrap up the thermal decomposition particles, so that the thermal decomposition particles of different diameters form condensation nuclei with consistent diameters, which makes it convenient for the detector to count the number of particles in the air and improves the accuracy of detecting the number of particles in the air.

[0025] The embodiment of the present application detects and alarms fires by counting the number of thermal decomposition particles instead of judging whether there is smoke. The current state of the monitoring area is comprehensively judged based on the number of background particles and the current number of particles in the monitoring area. The difference between the number of background particles and the number of particles in the very early stage of the fire is large, which makes the cloud chamber detector extremely accurate and reliable in detecting the very early stage of the fire, and will not cause false alarms due to the influence of dust, fog, dry ice, water vapor, high temperature and high humidity, etc.

[0026] As a feasible specific implementation method of the embodiment of the present application, the following steps are also included: Step S201: Divide the monitoring area into several partitions. The partitioning standard may be to divide the monitoring area into several equal parts, each part being a partition, or to divide the partitions according to the types of equipment inside the installation area of ​​the monitoring area; Step S202: independently obtaining the number of background particles in each partition; Step S203: an air intake pipe network for extracting top air is arranged in each partition, and the air intake pipe networks in different partitions are not interconnected; Step S204: the cloud chamber and the detector independently detect the number of particles in the current gas in each partition; Step S205: Determine whether there is a fire risk in each partition based on the current number of particles in the gas in each partition.

[0027] According to the above steps, the fire hazards of each partition in the monitoring area can be independently detected. When the number of particles in one or several partitions exceeds the number of background particles, the cloud chamber detector can accurately identify it, so that the operator can understand which specific partition is in the very early stage of the fire, reducing the operator's investigation time and further increasing the reaction time reserved for the operator.

[0028] On this basis, the following steps can also be included: Step S301: when the number of particles in a partition exceeds the number of background particles, an infrared detection image of the partition is acquired. The infrared detection image may be a temperature distribution image of the partition taken by an infrared detector; Step S302: judging whether there is a fire risk in the partition based on the current number of particles in the partition and the current infrared detection image.

[0029] By using infrared detection images after particle quantity identification to further determine the temperature of the equipment in the monitoring area, it is possible to determine whether the equipment is in the very early stages of a fire, thereby further improving the accuracy of monitoring the monitoring area.

[0030] Specifically, judging whether there is a fire risk in the partition based on the current number of particles in the partition and the current infrared detection image includes the following steps: Step S401: Obtain the type of combustible material in the current partition and the thermal breakdown temperature of the combustible material. The thermal breakdown temperatures of common combustible materials in the power distribution equipment in the power distribution room are as described in Table 1: Material Thermal breakdown point (℃) Flash point (℃) Polyvinyl chloride (PVC) 143 507 Acrylic 171 438 Cotton carpet 182 571 Polyethylene (PE) 210 488 Iron 260 399 Teflon 321 660 Table 1 Step S402: obtaining the distribution areas of several types of combustible materials in the current partition, that is, dividing the current partition into several blocks again according to the distribution of the several types of materials; Step S403: obtaining the current temperature of each combustible material distribution area based on the current infrared detection image of the partition; Step S404: Determine whether the current temperature of each distribution area exceeds the thermal breakdown temperature of the combustible material in the distribution area.

[0031] When the number of particles in the partition exceeds the number of background particles, the specific temperature of each type of combustible material in the partition is checked based on the infrared image. According to the type of combustible material and its current temperature, the specific type of combustible material that has undergone thermal collapse and its distribution position are determined, and the location information of the distribution area whose temperature exceeds the thermal collapse temperature of the combustible material in the area is obtained. In this way, when the number of particles in the partition exceeds the number of background particles, the operator can quickly and accurately find the place where the fire may occur for processing, which significantly improves the operator's response efficiency to the fire and reserves a lot of time for the operator's subsequent processing.

[0032] The embodiment of the present application also provides an advanced fire warning system based on pyrolysis particle detection, including: A cloud chamber, used to visualize particles in the gas in the monitoring area entering the cloud chamber, the cloud chamber having an exhaust port and an air inlet; A detector for counting particles in the gas entering the cloud chamber; The air suction pipe network is used to absorb the gas at the top of the monitoring area and send the top gas to the cloud chamber. The air outlet of the air suction pipe network is connected with the air inlet of the cloud chamber; Several valves are respectively arranged at the exhaust port and the air inlet of the mist chamber to control the opening and closing of the mist chamber; Infrared detector, used to detect the temperature information of each part in the monitoring area and form an infrared image of the temperature of the monitoring area; The processing unit is used to connect with the valve, the cloud chamber, the detector and the suction pipe network signal to control the working status of the valve, the cloud chamber, the detector and the suction pipe network.

[0033] When in use, the air intake pipe network draws air in the monitoring area into the cloud chamber. Several valves are closed to seal the cloud chamber. The cloud chamber forms supersaturated steam after humidification and pressure reduction, making the particles inside visible. The detector counts the number of condensation nuclei inside the cloud chamber to determine whether the monitored area is currently in the very early stage of a fire.

[0034] The detector may be a photodetector.

[0035] In some possible implementations of the embodiments of the present application, the air intake pipe network includes a vertical air intake pipe vertically arranged at the top of the device and a horizontal air intake pipe horizontally arranged at the top of the device. A bend pipe is installed between the top of the vertical air intake pipe and one end of the horizontal air intake pipe. The two ends of the bend pipe are respectively connected to the vertical air intake pipe and the horizontal air intake pipe. The bend pipe reduces the obstruction of the air intake pipe network to the gas, so that the gas can flow more smoothly inside the air intake pipe network, thereby making the subsequent particle counting more accurate. On this basis, a number of sampling holes are opened at the bottom of the horizontal suction pipe, the end of the horizontal suction pipe is connected to the cloud chamber, and a terminal hole is opened on the outside of the end of the horizontal suction pipe. Through the setting of a number of sampling holes and terminal holes, the suction pipe network can extract the air in the monitoring area more evenly when working, thereby improving the subsequent particle counting effect, and when the valve is closed, the terminal hole and a number of sampling holes can also balance the internal pressure of the suction pipe network, reduce the occurrence of air hammer phenomenon, and thus improve the accuracy of particle counting.

[0036] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An advanced fire warning method based on pyrolysis particle detection, characterized in that: include: Set up the cloud chamber and detectors; Get the number of background particles in the monitoring area; Lay out a suction pipe network at the top of the monitoring area; The gas at the top of the monitoring area is sucked into the cloud chamber through the suction pipe network; Humidification and depressurization of the cloud chamber; Get the current number of particles in the cloud chamber; Compare the current number of particles in the monitoring area with the number of background particles; Determine whether there is a fire risk in the monitored area based on the comparison results.

2. The advanced fire warning method based on pyrolysis particle detection according to claim 1 is characterized in that: Obtaining the number of background particles in the monitoring area includes: Set up several sampling points within the monitoring area; Extract the top air of several sampling points respectively, and draw the top air of the aforementioned sampling points into the cloud chamber; The cloud chamber is humidified and depressurized to make the particles in the top air of the sampling point visible in the cloud chamber; Count the number of condensation nuclei in the cloud chamber; The number of particles in the top air of several sampling points is weighted averaged to obtain the number of background particles in the monitoring area.

3. The advanced fire warning method based on pyrolysis particle detection according to claim 1 is characterized in that: Also includes: Divide the monitoring area into several zones; Get the number of background particles in each partition; A suction pipe network is laid out in each partition; The cloud chamber and detector independently detect the number of particles in the current gas in each partition; Determine whether there is a fire risk in each partition based on the current number of particles in the gas in each partition.

4. The advanced fire warning method based on pyrolysis particle detection according to claim 3 is characterized in that: Also includes: When the number of particles in a partition exceeds the number of background particles, an infrared detection image of the partition is obtained; Based on the current number of particles in the partition and the current infrared detection image, it is determined whether the partition has a fire risk.

5. The advanced fire warning method based on pyrolysis particle detection according to claim 4 is characterized in that: Based on the current number of particles in the partition and the current infrared detection image, determine whether the partition has a fire risk, including: Get the type of combustible material and the thermal collapse temperature of the combustible material in the current partition; Get the distribution areas of several types of combustible materials in the current zone; Based on the current infrared detection image of the partition, the current temperature of each combustible material distribution area is obtained; Determine whether the current temperature of each distribution area exceeds the thermal collapse temperature of the combustible material in its distribution area.

6. The advanced fire warning method based on pyrolysis particle detection according to claim 5 is characterized in that: Also includes: When the number of particles in the partition exceeds the number of background particles, the position information of the distribution area whose temperature exceeds the thermal breakdown temperature of the combustible material in the area is obtained.

7. An advanced fire warning system based on pyrolysis particle detection, characterized in that: include: A cloud chamber, used to visualize particles in the gas in the monitoring area entering the cloud chamber; A detector for counting particles in the gas entering the cloud chamber; The suction pipe network is used to absorb the gas at the top of the monitoring area and send the top gas to the cloud chamber; Infrared detector, used to detect the temperature information of each part in the monitoring area and form an infrared image of the temperature of the monitoring area; The processing unit is used to connect with the cloud chamber, the detector and the air intake pipe network signals to control the working status of the cloud chamber, the detector and the air intake pipe network.

8. The advanced fire warning system based on pyrolysis particle detection according to claim 7 is characterized in that: The air intake pipe network includes a vertical air intake pipe vertically arranged on the top of the equipment and a horizontal air intake pipe horizontally arranged on the top of the equipment. A bend pipe is installed between the top of the vertical air intake pipe and one end of the horizontal air intake pipe. The two ends of the bend pipe are respectively connected to the vertical air intake pipe and the horizontal air intake pipe.

9. The advanced fire warning system based on pyrolysis particle detection according to claim 8, characterized in that: A plurality of sampling holes are arranged at the bottom of the horizontal suction pipe, the end of the horizontal suction pipe is communicated with the cloud chamber, and an end hole is arranged outside the end of the horizontal suction pipe.

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