CN101825562A - Method for detecting coal mine gas concentration based on dual wavelength laser - Google Patents
Method for detecting coal mine gas concentration based on dual wavelength laser Download PDFInfo
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Abstract
The invention discloses a method for detecting coal mine gas concentration based on dual wavelength laser, which is characterized by arranging a detecting system composed of two laser transmitters, two fiber-optic attenuators, an optical switch, a gas detector, a photoelectric converter and a monitoring computer, connecting the laser transmitters, the fiber-optic attenuators, the optical switch, the gas detector and the photoelectric converter in sequence by optical fibers; connecting the monitoring computer to the optical switch and the photoelectric converter; the two laser transmitters respectively transmitting laser with wavelength of 1666nm and laser with wavelength of 1664nm and switching mutually; sending the laser to the gas detector via the fiber-optic attenuators and the optical switch, converting the detected optical signals to electric signals through photoelectric conversion, amplifying the electric signals to the standard signals, transmitting the standard signals to A/D to be converted into the digital signals and transmitting the digital signals to CPU to be processed, thereby measuring the gas concentration. The method has the advantages of high detection sensitivity, good adaptability to underground high humidity environment, fast response, overlong service life, long detection range and extremely low maintenance cost, and is suitable for monitoring coal mine gas.
Description
Technical field
The present invention relates to the method for utilizing optical instrument to test, also relate to the mine telltale, furthermore, belong to the method that adopts laser that coal mine gas concentration is detected.
Background technology
Gas is the gas that produces in the coal seam, and its principal ingredient is a methane.Meet naked light at the gas of explosion limits and promptly blast, miner's life is threatened greatly.Therefore the detection to gas density is the important process of mine.The detection of the gas of widespread use is to adopt traditional electrochemical means to carry out at present, and there is following shortcoming in the traditional electrical chemical mode: 1. need regularly sensor to be proofreaied and correct, and proofread and correct loaded down with trivial details; 2. detection speed is low, about 20 seconds detection times; 3. accuracy of detection is low, can only detect CH
4Massfraction is about 0.1%; 4. detecting distance is 2km only; 5. serviceable life is low; 6. poor anti jamming capability.
Optical gas sensor is a kind of novel sensor that occurs in recent years, and it mainly refers to utilize medium light absorption to be made light produce decay and produces the gas sensor that characteristic such as interference fringe is made owing to the interference of light of different light paths.Optical fiber is used for gas sensing the incomparable advantage of other sensor: 1. be convenient to multiplexingly, be convenient to into net; 2. anti-electromagnetic interference (EMI), electrical isolation, corrosion-resistant are suitable for measuring flammable explosion hazard gases or work in inflammable and strong electromagnetic interference environment measurement down; 3. sensing unit is simple in structure, and is reliable and stable; 4. in light weight, volume is little, shape variable; 5. highly sensitive.
The light absorption gas sensor is except the advantage that possesses above-mentioned optical gas sensor and have, it is simple also to have light path, can accurately measure and can be simultaneously composition, the concentration of other gas such as be detected at characteristics methane gas concentration, composition, thereby remedy the shortcoming that optical interferometry can not carry out Measurement and analysis to the concrete composition of gas.200610044428.1 number patented claim discloses a kind of " gas differential absorbing monitoring system with fibre-optical and multi-point in mine ".Present stage light absorption methane gas detection method is to utilize the spectral absorption of methane gas to come detected gas concentration, because the absorption line of gas with various takes on a different character, so they can also distinguish different gas and the volume ratio of this gas in mixed gas to a certain extent from mixed gas.But also existing light path complexity, flashing reaches photoelectric device zero point drift surely and influences defectives such as measuring accuracy.
Summary of the invention
The present invention is directed to the above-mentioned shortcoming of traditional product, mainly solve the problem such as correction, detection speed, precision, distance, serviceable life, adaptive capacity to environment of sensor, a kind of method for detecting coal mine gas concentration based on dual-wavelength laser is provided.
Method for detecting coal mine gas concentration of the present invention is to adopt laser that gas density is detected; Specific practice is: be provided with by two generating lasers, two detection systems that fibre optic attenuator, photoswitch, gas detector, photoelectric commutator, supervisory control comuter are formed, generating laser, fibre optic attenuator, photoswitch, gas detector and photoelectric commutator are connected with optical fiber successively; Supervisory control comuter then is connected to photoswitch and photodetector; Two laser generators are launched the laser of 1666nm wavelength and the laser of 1666nm wavelength respectively, switch mutually; The laser that sends is delivered to gas detector by fibre optic attenuator and photoswitch, detected light signal is sent electric signal through opto-electronic conversion, electric signal is enlarged into standard signal gives A/D conversion, obtain digital signal, and send CPU to handle, thereby measure gas density.
Above-mentioned supervisory control comuter is the CPU processor.
The time that above-mentioned two laser generators switch mutually is controlled between 1 to 5ms.
This detector profile of above-mentioned gas detector is a rectangular box, and air chamber, filtering layer, adjustment cover plate, operation cover plate are arranged in the box, and box has fibre-optical splice outward; Its center is an air chamber, and air chamber inside is equipped with two corresponding collimating apparatus optical lens, and these collimating apparatus optical lens are connected with gas monitoring system by the outer fibre-optical splice of air chamber; Air chamber below has the operation cover plate and has the adjustment cover plate, is installed on the air chamber when moving in system respectively or when adjustment detector and gas monitoring system.
Above-mentioned generating laser, fibre optic attenuator, photoswitch, photoelectric commutator are the commercially available prod.
The principle of work of method for detecting coal mine gas concentration of the present invention is: because the laser of the 1666nm wavelength of a generation in two laser generators only has methane gas is had high sensitivity, therefore adopt the laser of 1666nm wavelength gas density to be detected the subtle change that can detect gas, can improve monitoring sensitivity and sensing range by the gas field under the mine.And the gas density size in the gas detector can be by detected photosignal size, and process is converted to digital signal, and send CPU to handle, and calculates concentration; CPU sends control signal to photoswitch simultaneously, realizes the control to laser detection system.Because coal mine environment is abominable, has higher humidity, can cause accuracy of detection and have a strong impact on, therefore switch to the laser of 1664nm wavelength by photoswitch, ambient humidity is detected, can can correctly detect gas density from the difference of the electric signal size of two-beam, eliminate the influence of ambient humidity.Fibre optic attenuator behind two laser instruments then is used for regulating automatically both power unanimities, guarantees power match, improves system reliability.
Detection method of the present invention has the following advantages: to gas detection sensitivity height, the high humidity environment that can adapt to the down-hole, response time fast, serviceable life overlength, detection range is long, maintenance cost is extremely low.Be applicable to the monitoring of coal mine gas.
Description of drawings
Fig. 1 is that the used detection system of method of the present invention is formed synoptic diagram, and Fig. 2 is the structural representation of photodetector.
1 is shell among the figure, and 2 is air chamber, and 3 is the collimating apparatus optical lens, and 4 are the operation cover plate, and 5 is pore, and 6 is trip bolt, and 7 is filtering layer, and 8 is fiber connector.
Embodiment
In certain mine down-hole the methane gas detector is installed, two generating lasers, fibre optic attenuator, photoswitch, photodetector and computing machines is installed, form a cover gas detection system in the aboveground part of mine.The generating laser of system, fibre optic attenuator, photoswitch, gas detector and photodetector are connected with optical fiber successively; Supervisory control comuter then is connected to photoswitch and photodetector.
This detector profile of gas detector is a rectangular box, and air chamber, filtering layer, adjustment cover plate, operation cover plate are arranged in the box, and box has fibre-optical splice outward; Its center is an air chamber, and air chamber inside is equipped with 2～6 group of two corresponding collimating apparatus optical lens, and these collimating apparatus optical lens are connected with gas monitoring system by the outer fibre-optical splice of air chamber; It is installed on the air chamber when moving cover plate or adjustment cover plate and move in system respectively or when adjustment detector and gas monitoring system down.
Used generating laser is wavelength 1666nm and 1664nm optical semiconductor fibre laser.
Used fibre optic attenuator is electric scalable fibre optic attenuator EVOA.
Used photoswitch is the photoswitch of 1 * 2 type.
Used photodetector is 1700nm long wavelength's detector.
Concrete working routine is: the gas detector of launching laser and using Optical Fiber Transmission to install to the down-hole with the 1666nm long wavelength laser, the laser signal of gas detector output send aboveground photoelectric commutator, send the AD transition card in the computing machine to carry out data acquisition, on computer interface, show the gas density of down-hole point; The light of the 1664nm wavelength that timesharing is switched then is used to eliminate the ambient humidity influence.Be controlled at switching time between 1 to 5ms.
Claims (5)
1. method for detecting coal mine gas concentration based on dual-wavelength laser, adopt laser that gas density is detected, it is characterized in that this method is to be provided with by two generating lasers, two detection systems that fibre optic attenuator, photoswitch, gas detector, photoelectric commutator, supervisory control comuter are formed; Generating laser, fibre optic attenuator, photoswitch, gas detector and photodetector are connected with optical fiber successively; Supervisory control comuter then is connected to photoswitch and photodetector; Two laser generators are launched the laser of 1666nm wavelength and the laser of 1666nm wavelength respectively, switch mutually; The laser that sends is delivered to gas detector by fibre optic attenuator and photoswitch, detected light signal is sent electric signal through opto-electronic conversion, electric signal is enlarged into standard signal gives A/D conversion, obtain digital signal, and send CPU to handle, thereby measure gas density; CPU sends control signal to photoswitch simultaneously, realizes the control to laser detection system.
2. the method for claim 1 is characterized in that described supervisory control comuter is the CPU processor.
3. the method for claim 1 is characterized in that the time that described two laser generators switch mutually is controlled between 1～5ms.
4. the method for claim 1 is characterized in that this detector profile of described gas detector is a rectangular box, and air chamber, filtering layer, adjustment cover plate, operation cover plate are arranged in the box, and box has fibre-optical splice outward; Its center is an air chamber, and air chamber inside is equipped with two corresponding collimating apparatus optical lens, and these collimating apparatus optical lens are connected with gas monitoring system by the outer fibre-optical splice of air chamber; Air chamber below has the operation cover plate and has the adjustment cover plate, is installed on the air chamber when moving in system respectively or when adjustment detector and gas monitoring system.
5. the method for claim 1 is characterized in that described generating laser, fibre optic attenuator, photoswitch, photoelectric commutator are the commercially available prod.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201010123863A CN101825562A (en) | 2010-03-15 | 2010-03-15 | Method for detecting coal mine gas concentration based on dual wavelength laser |
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| CN201010123863A CN101825562A (en) | 2010-03-15 | 2010-03-15 | Method for detecting coal mine gas concentration based on dual wavelength laser |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102252982A (en) * | 2011-04-29 | 2011-11-23 | 安徽皖仪科技股份有限公司 | Wavelength drift compensation method for laser gas analyzer |
| CN105738318A (en) * | 2016-02-18 | 2016-07-06 | 北京航天易联科技发展有限公司 | Environment humidity monitoring method and system for cultural relic preservation |
| CN106959308A (en) * | 2017-03-20 | 2017-07-18 | 东南大学 | A kind of concrete structure influence of fire depth detection method |
| CN107064058A (en) * | 2017-01-05 | 2017-08-18 | 中国地质调查局水文地质环境地质调查中心 | A kind of shale gas leakage multiple gases on-Line Monitor Device and method |
| CN110715906A (en) * | 2018-07-13 | 2020-01-21 | 横河电机株式会社 | Spectrum measuring apparatus and spectrum measuring method |
| CN110715905A (en) * | 2018-07-13 | 2020-01-21 | 横河电机株式会社 | Spectrum measuring apparatus |
| CN112362597A (en) * | 2020-11-16 | 2021-02-12 | 安徽中科瀚海光电技术发展有限公司 | Multi-path laser gas monitoring system and monitoring method |
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2010
- 2010-03-15 CN CN201010123863A patent/CN101825562A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102252982A (en) * | 2011-04-29 | 2011-11-23 | 安徽皖仪科技股份有限公司 | Wavelength drift compensation method for laser gas analyzer |
| CN105738318A (en) * | 2016-02-18 | 2016-07-06 | 北京航天易联科技发展有限公司 | Environment humidity monitoring method and system for cultural relic preservation |
| CN105738318B (en) * | 2016-02-18 | 2018-11-06 | 北京航天易联科技发展有限公司 | One kind being used for historical relic's protection ambient humidity monitoring method and its system |
| CN107064058A (en) * | 2017-01-05 | 2017-08-18 | 中国地质调查局水文地质环境地质调查中心 | A kind of shale gas leakage multiple gases on-Line Monitor Device and method |
| CN107064058B (en) * | 2017-01-05 | 2020-08-21 | 中国地质调查局水文地质环境地质调查中心 | Shale gas leakage multiple gas online monitoring device and method |
| CN106959308A (en) * | 2017-03-20 | 2017-07-18 | 东南大学 | A kind of concrete structure influence of fire depth detection method |
| CN106959308B (en) * | 2017-03-20 | 2020-04-07 | 东南大学 | Method for detecting fire influence depth of concrete structure |
| CN110715906A (en) * | 2018-07-13 | 2020-01-21 | 横河电机株式会社 | Spectrum measuring apparatus and spectrum measuring method |
| CN110715905A (en) * | 2018-07-13 | 2020-01-21 | 横河电机株式会社 | Spectrum measuring apparatus |
| CN110715905B (en) * | 2018-07-13 | 2022-06-14 | 横河电机株式会社 | Spectrum measuring apparatus |
| CN112362597A (en) * | 2020-11-16 | 2021-02-12 | 安徽中科瀚海光电技术发展有限公司 | Multi-path laser gas monitoring system and monitoring method |
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Application publication date: 20100908 |