CN111192431A - Single ultraviolet flame detector and false alarm prevention method - Google Patents
Single ultraviolet flame detector and false alarm prevention method Download PDFInfo
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- CN111192431A CN111192431A CN201911384647.8A CN201911384647A CN111192431A CN 111192431 A CN111192431 A CN 111192431A CN 201911384647 A CN201911384647 A CN 201911384647A CN 111192431 A CN111192431 A CN 111192431A
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- 238000000034 method Methods 0.000 title claims abstract description 12
- 230000002265 prevention Effects 0.000 title claims description 6
- 238000012360 testing method Methods 0.000 claims description 20
- 238000001514 detection method Methods 0.000 claims description 13
- 238000007493 shaping process Methods 0.000 claims description 13
- 238000002474 experimental method Methods 0.000 claims description 11
- 230000003750 conditioning effect Effects 0.000 claims description 7
- 238000012545 processing Methods 0.000 claims description 3
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 230000035945 sensitivity Effects 0.000 description 10
- 230000005855 radiation Effects 0.000 description 7
- 238000002485 combustion reaction Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 239000005519 non-carbonaceous material Substances 0.000 description 3
- 230000003595 spectral effect Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 201000004569 Blindness Diseases 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 238000013142 basic testing Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000003721 gunpowder Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 230000002085 persistent effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/12—Actuation by presence of radiation or particles, e.g. of infrared radiation or of ions
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Abstract
The invention belongs to the field of fire fighting equipment, relates to the field of flame detectors, and particularly provides a single ultraviolet flame detector and an anti-false alarm method aiming at the problem of false alarm of the single ultraviolet flame detector. The single ultraviolet flame detector has certain environmental interference resistance through the combination of software and hardware, and simultaneously effectively solves the problem of false alarm caused by the self discharge characteristic of the ultraviolet phototube, thereby improving the reliability of the single ultraviolet flame detector and the overall performance of the single ultraviolet flame detector.
Description
Technical Field
The invention belongs to the field of fire fighting equipment, relates to the field of flame detectors, and particularly relates to a single ultraviolet flame detector and an anti-false alarm method.
Technical Field
The flame detector is an important component of an automatic fire extinguishing and explosion suppression system, and is widely applied to the fields of military armored vehicles, fuel oil depots, gunpowder production lines, ammunition depots and the like at present. Through decades of development, various flame detectors including single ultraviolet, multiple ultraviolet, single infrared, multiple infrared, ultraviolet infrared, single ultraviolet multiple infrared, and the like have been developed, and have been widely applied in different fields.
Conventional infrared flame detectors are not capable of detecting a combustion flame of non-carbonaceous materials, such as flames produced by the combustion of non-carbonaceous materials, such as hydrogen, phosphorus, lithium metal, and the like. Ultraviolet flame detectors are commonly used to detect fires resulting from the combustion of such non-carbonaceous materials. The single ultraviolet flame detector is applied to special occasions with infrared radiation interference sources, such as heating furnaces, industrial boilers, vehicle power cabins and the like, due to the advantage of low cost. However, the higher false alarm rate of a single uv flame detector is a persistent and not yet effectively addressed problem.
Disclosure of Invention
In view of the above situation, the technical problem to be solved by the present invention is: the single ultraviolet flame detector has the false alarm problem, especially the false alarm problem caused by the self-discharge characteristic of the ultraviolet photoelectric tube.
In order to solve the technical problems, the technical scheme of the invention is as follows: providing a single ultraviolet flame detector and a false alarm prevention method; the false alarm problem of the single ultraviolet flame detector is mainly solved by hardware-level filtering, an ultraviolet phototube self-discharge test experiment and a CPU software algorithm identification method.
1. Hardware design
A single ultraviolet flame detector mainly comprises: the ultraviolet sensor and the ultraviolet signal conditioning circuit; the ultraviolet sensor adopts a solar blind type ultraviolet photoelectric tube, and filters an interference source existing in the environment from a detection source, so that the overall reliability of the system is greatly guaranteed; the ultraviolet signal conditioning circuit mainly comprises: the ultraviolet photoelectric tube power supply and output circuit and the ultraviolet pulse signal amplitude limiting and shaping circuit; the ultraviolet phototube is connected with an ultraviolet pulse signal amplitude limiting and shaping circuit and is used for processing a high-voltage pulse signal directly output by the ultraviolet phototube so as to enable the high-voltage pulse signal to be matched with the level accepted by the processor.
The amplitude limiting and shaping circuit has two schemes, one scheme is that ultraviolet high-voltage pulses are subjected to amplitude limiting by a voltage regulator tube D1 to be level which can be processed by a CPU, then the ultraviolet high-voltage pulses are shaped into square signals by a comparator U1, and the duty ratio of the square signals can be adjusted by adjusting a slide rheostat RP 1; secondly, the ultraviolet high-voltage pulse is subjected to amplitude limiting by a voltage regulator tube D2 and a diode D3 to be the level which can be processed by a CPU, and then is shaped into a square wave signal by a reverse Schmitt trigger U2; the use of a schmitt trigger can help to enhance the anti-interference performance of the system.
2. Self discharge test
In order to realize the self-discharge characteristic false alarm function of the immune ultraviolet phototube, a plurality of ultraviolet phototubes are required to be made into oneAnd (3) carrying out a self-discharge test experiment with a fixed time length (the longer the test time is, the more real and reliable the data is) so as to master the self-discharge rule and lay the foundation for identifying the software fire algorithm. The main parameters tested were two: maximum duration of one self-discharge
And minimum time interval of two self-discharges
。
The experimental condition is the environment without an ultraviolet interference source, the power supply voltage of the ultraviolet photoelectric tube is properly adjusted to ensure that the ultraviolet photoelectric tube can normally work, does not generate self-excitation and keeps proper sensitivity.
3. Software algorithm
The processor monitors and collects ultraviolet pulse data in real time and combines the data from the discharge test experiment, and the duration of the input ultraviolet pulse signal is assumed to be
Satisfies the following formula:
it is judged as requirement 1 for fire alarm.
And (3) calculating effective detection once as long as the ultraviolet pulse data meets the formula (1), simultaneously finishing the current timing detection, and starting the next timing detection.
Suppose that the last time the UV pulse signal was detected is
The time for detecting the ultraviolet pulse signal is
Satisfies the following formula:
it is judged as a fire alarm requirement 2.
If the formula (1) and the formula (2) are satisfied at the same time, it can be judged that a fire occurs.
The algorithm needs to detect the effective ultraviolet pulse signal at least twice continuously, and has the advantages of high reliability and low false alarm rate. The disadvantage is a slightly slower response time. If the response time is to be accelerated, the detection can be performed only once on the effective ultraviolet pulse signalFor a fire alarm, in general, this case equation (2) is not satisfied, but it is possible to increase equation (1) appropriately
The fire alarm is judged according to the value so as to balance the contradiction between the anti-interference capability and the response time.
The solar blind spectral region refers to ultraviolet radiation with the wavelength of 200-280 nm. Solar radiation is said to be "solar blind" because the light waves in this band are almost completely absorbed by the earth's ozone layer, i.e. the background radiation in the atmospheric layer in this band is almost zero. The solar blind type ultraviolet photoelectric tube only responds to the radiation of an ultraviolet wave band in a solar blind spectral region, and the wave band is the wave band with the strongest ultraviolet radiation in the combustion flame. Therefore, the ultraviolet radiation in the spectral range of the solar dead zone is utilized to detect the fire, so that the background interference is minimized, the system is stable and reliable to operate, and the false alarm rate is low. Therefore, the interference source existing in the environment can be filtered from the detected source, and the overall reliability of the system is greatly guaranteed.
The invention has the beneficial effects that: by combining software and hardware, the single ultraviolet flame detector not only has certain environmental interference resistance, but also effectively solves the problem of false alarm caused by the self discharge characteristic of the ultraviolet phototube, thereby improving the reliability of the single ultraviolet flame detector and the overall performance of the single ultraviolet flame detector.
Drawings
FIG. 1 is a schematic diagram of a power supply and output circuit of an ultraviolet photoelectric tube;
FIG. 2 is a schematic diagram of a UV pulse signal limiting and shaping circuit;
FIG. 3 is a schematic diagram of a second scheme of the ultraviolet pulse signal amplitude limiting and shaping circuit;
FIG. 4 is a schematic diagram showing the comparison of waveforms before and after shaping of the UV pulse signal;
fig. 5 is uv photocell test data.
Detailed Description
The invention relates to a false alarm prevention method for a single ultraviolet flame detector, which mainly comprises hardware-level anti-interference design, basic test experiments and software algorithms.
Providing a single ultraviolet flame detector and a false alarm prevention method; the false alarm problem of the single ultraviolet flame detector is mainly solved by hardware-level filtering, an ultraviolet phototube self-discharge test experiment and a CPU software algorithm identification method.
1. Hardware design
A single ultraviolet flame detector mainly comprises: the ultraviolet sensor and the ultraviolet signal conditioning circuit; the ultraviolet sensor adopts a solar blind type ultraviolet photoelectric tube, and filters an interference source existing in the environment from a detection source, so that the overall reliability of the system is greatly guaranteed; the ultraviolet signal conditioning circuit mainly comprises: the ultraviolet photoelectric tube power supply and output circuit and the ultraviolet pulse signal amplitude limiting and shaping circuit; the ultraviolet phototube is connected with an ultraviolet pulse signal amplitude limiting and shaping circuit and is used for processing a high-voltage pulse signal directly output by the ultraviolet phototube so as to enable the high-voltage pulse signal to be matched with the level accepted by the processor.
The amplitude limiting and shaping circuit has two schemes, one scheme is that ultraviolet high-voltage pulses are subjected to amplitude limiting by a voltage regulator tube D1 to be level which can be processed by a CPU, then the ultraviolet high-voltage pulses are shaped into square signals by a comparator U1, and the duty ratio of the square signals can be adjusted by adjusting a slide rheostat RP 1; secondly, the ultraviolet high-voltage pulse is subjected to amplitude limiting by a voltage regulator tube D2 and a diode D3 to be the level which can be processed by a CPU, and then is shaped into a square wave signal by a reverse Schmitt trigger U2; the use of a schmitt trigger can help to enhance the anti-interference performance of the system.
2. Self discharge test
In order to realize the self-discharge characteristic false alarm function of the immune ultraviolet phototubes, a plurality of ultraviolet phototubes need to be subjected to a self-discharge test experiment for a certain time (the longer the test time is, the more real and reliable the data is) so as to master the self-discharge rule of the multiple ultraviolet phototubes and lay the foundation for identifying the software fire algorithm. The main parameters tested were two: maximum duration of one self-discharge
And minimum interval between two self-dischargesTime interval
。
The experimental condition is the environment without an ultraviolet interference source, the power supply voltage of the ultraviolet photoelectric tube is properly adjusted to ensure that the ultraviolet photoelectric tube can normally work, does not generate self-excitation and keeps proper sensitivity.
3. Software algorithm
The processor monitors and collects ultraviolet pulse data in real time and combines the data from the discharge test experiment, and the duration of the input ultraviolet pulse signal is assumed to be
Satisfies the following formula:
it is judged as requirement 1 for fire alarm.
And (3) calculating effective detection once as long as the ultraviolet pulse data meets the formula (1), simultaneously finishing the current timing detection, and starting the next timing detection.
Suppose that the last time the UV pulse signal was detected is
The time for detecting the ultraviolet pulse signal is
Satisfies the following formula:
it is judged as a fire alarm requirement 2.
If the formula (1) and the formula (2) are satisfied at the same time, it can be judged that a fire occurs.
The algorithm needs to detect the effective ultraviolet pulse signal at least twice continuously, and has the advantages of high reliability and low false alarm rate. The disadvantage is a slightly slower response time. If the response time is to be increased, the fire alarm can be judged by detecting the effective ultraviolet pulse signal only once, in general, the formula (2) is not satisfied in the case of the fire alarm, but the formula (1) can be increased appropriately
The fire alarm is judged according to the value so as to balance the contradiction between the anti-interference capability and the response time.
At present, the quality of the ultraviolet phototube of each manufacturer is greatly different, and in order to ensure the reliability of the single ultraviolet flame detector, the ultraviolet phototube should be purchased by manufacturers with the characteristics of solar blindness as much as possible. The two schemes of amplitude limiting and shaping in the ultraviolet signal conditioning circuit can be preferentially considered as the second scheme. For ultraviolet phototubes of the same manufacturer, a self-discharge test experiment generally only needs to be carried out for the first time, and the tested data can be generally used for ultraviolet phototubes of different batches as long as the production process and raw materials of the manufacturer are unchanged. The software code of the processor is combined with the test data and is compiled strictly according to the algorithm of the invention, so that the problem of high false alarm rate of the single ultraviolet flame detector can be effectively solved.
The development of a single ultraviolet flame detector prototype is completed according to the method, a large number of verification tests are carried out, the test result is good, and the condition of false alarm does not occur. And preparing small batches for supply. The data related to the self-discharge test of the selected 10 ultraviolet phototubes R2868 are shown in FIG. 5.
Claims (3)
1. A single ultraviolet flame detector, characterized by: the structure mainly comprises: the ultraviolet sensor and the ultraviolet signal conditioning circuit; the ultraviolet sensor adopts a solar blind type ultraviolet photoelectric tube, and filters an interference source existing in the environment from a detection source, so that the overall reliability of the system is greatly guaranteed; the ultraviolet signal conditioning circuit mainly comprises: the ultraviolet photoelectric tube power supply and output circuit and the ultraviolet pulse signal amplitude limiting and shaping circuit; the ultraviolet phototube is connected with an ultraviolet pulse signal amplitude limiting and shaping circuit and is used for processing a high-voltage pulse signal directly output by the ultraviolet phototube so as to enable the high-voltage pulse signal to be matched with the level accepted by the processor.
2. The single ultraviolet flame detector of claim 1, wherein: the amplitude limiting and shaping circuit has two schemes, one scheme is that ultraviolet high-voltage pulses are subjected to amplitude limiting by a voltage regulator tube D1 to be level which can be processed by a CPU, then the ultraviolet high-voltage pulses are shaped into square signals by a comparator U1, and the duty ratio of the square signals can be adjusted by adjusting a slide rheostat RP 1; secondly, the ultraviolet high-voltage pulse is subjected to amplitude limiting by a voltage regulator tube D2 and a diode D3 to be the level which can be processed by a CPU, and then is shaped into a square wave signal by a reverse Schmitt trigger U2; the use of a schmitt trigger can help to enhance the anti-interference performance of the system.
3. A single ultraviolet flame detector false alarm prevention method mainly adopts an ultraviolet phototube self-discharge test experiment and a CPU software algorithm identification method, and is characterized in that:
(1) the self-discharge test: in the environment without an ultraviolet interference source, the power supply voltage of the ultraviolet photoelectric tubes is properly adjusted to ensure that the ultraviolet photoelectric tubes can normally work without self-excitation, and a plurality of ultraviolet photoelectric tubes are subjected to a self-discharge test experiment for a certain time to master the self-discharge rule of the ultraviolet photoelectric tubes; the main parameters tested were two: maximum duration of one self-discharge
And minimum time interval of two self-discharges
；
(2) Software algorithm
The processor monitors and collects ultraviolet pulse data in real time and combines the data from the discharge test experiment, and the duration of the input ultraviolet pulse signal is assumed to be
Satisfies the following formula:
judging as a necessary condition 1 for fire alarm;
As long as the ultraviolet pulse data meets the formula (1), calculating effective detection once, simultaneously finishing the current timing detection, and starting the next timing detection;
suppose that the last time the UV pulse signal was detected is
The time for detecting the ultraviolet pulse signal is
Satisfies the following formula:
judging as a necessary condition 2 for fire alarm;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911384647.8A CN111192431A (en) | 2019-12-28 | 2019-12-28 | Single ultraviolet flame detector and false alarm prevention method |
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| CN201911384647.8A CN111192431A (en) | 2019-12-28 | 2019-12-28 | Single ultraviolet flame detector and false alarm prevention method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115273385A (en) * | 2022-07-11 | 2022-11-01 | 杭州海康威视数字技术股份有限公司 | Camera for flame detection |
| CN115410334A (en) * | 2022-08-29 | 2022-11-29 | 浙江华消科技有限公司 | Flame detection device and method |
-
2019
- 2019-12-28 CN CN201911384647.8A patent/CN111192431A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115273385A (en) * | 2022-07-11 | 2022-11-01 | 杭州海康威视数字技术股份有限公司 | Camera for flame detection |
| CN115273385B (en) * | 2022-07-11 | 2024-03-26 | 杭州海康威视数字技术股份有限公司 | A camera for flame detection |
| CN115410334A (en) * | 2022-08-29 | 2022-11-29 | 浙江华消科技有限公司 | Flame detection device and method |
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Application publication date: 20200522 |
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