CN102841074A - Method for measuring coal mine gas by using laser wavelength scanning optical fiber of temperature control semiconductor - Google Patents
Method for measuring coal mine gas by using laser wavelength scanning optical fiber of temperature control semiconductor Download PDFInfo
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- CN102841074A CN102841074A CN2012103479841A CN201210347984A CN102841074A CN 102841074 A CN102841074 A CN 102841074A CN 2012103479841 A CN2012103479841 A CN 2012103479841A CN 201210347984 A CN201210347984 A CN 201210347984A CN 102841074 A CN102841074 A CN 102841074A
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 34
- 239000013307 optical fiber Substances 0.000 title claims abstract description 25
- 239000003245 coal Substances 0.000 title claims abstract description 8
- 238000000034 method Methods 0.000 title claims description 15
- 238000012545 processing Methods 0.000 claims abstract description 8
- 230000003287 optical effect Effects 0.000 claims description 11
- 238000010521 absorption reaction Methods 0.000 abstract description 15
- 238000005516 engineering process Methods 0.000 abstract description 5
- 230000035945 sensitivity Effects 0.000 abstract description 2
- 239000000969 carrier Substances 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 43
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 10
- 238000001514 detection method Methods 0.000 description 7
- 238000012544 monitoring process Methods 0.000 description 6
- 238000004880 explosion Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 238000000862 absorption spectrum Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009841 combustion method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 238000002848 electrochemical method Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012806 monitoring device Methods 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
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- 238000011160 research Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000009967 tasteless effect Effects 0.000 description 1
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Abstract
The invention discloses a technology for measuring coal mine gas by using a laser wavelength scanning optical fiber of a temperature control semiconductor. The technology is characterized in that a constant-current source drives a semiconductor distributed feedback (DFB) laser device; an output wavelength of the semiconductor DFB laser device is close to a gas absorption peak and is scanned by changing the working temperature of the semiconductor DFB laser device; light output by the semiconductor DFB laser device is injected to a measured gas chamber; output light of the gas chamber carriers gas concentration information; a photoelectric detector converts a light signal into an electric signal; an analog-to-digital (A/D) acquisition card acquires the electric signal to a signal processing system; wavelength scanning of the semiconductor DFB laser device is resulted from temperature scanning; in the wavelength scanning range, the absorption peak of the gas exists; and the concentrationof gas can be calculated by comparing the light power at the position with the absorption peak with the light power at the position without the absorption peak. The sensing system is simple in structure and high in sensitivity.
Description
Technical Field
The invention belongs to the technical field of optical fiber sensing, and particularly relates to a coal mine gas measurement method.
Background
The gas is a colorless, tasteless, inflammable and explosive gas, and the main component of the gas is methane. The gas explosion needs to simultaneously meet three conditions of gas with certain concentration, existence of high-temperature fire source, sufficient oxygen and the like, and the explosion limit of the gas is 5-16%. In China, accidents caused by gas explosion cause great damage to the life safety of people, so that the reduction or avoidance of the gas explosion accidents becomes an urgent task. The concentration of the gas is accurately, quickly and timely monitored and early warned, and the method has important effects on safety production, personal safety and environmental protection of coal mines.
At present, there are various methods for monitoring the concentration of gas, mainly including optical methods, electrochemical methods, semiconductor methods, contact combustion methods, and the like. The optical fiber sensor has the characteristics of stability, reliability, strong anti-electromagnetic interference capability, good electrical insulation, explosion resistance, long-distance long-term on-line measurement, simple structure of the sensing unit, easiness in forming an optical fiber sensing network and the like, and is suitable for measuring the gas concentration in severe dangerous environments. The optical fiber sensing gas measurement method can be further divided into modes of differential absorption, harmonic detection and the like according to the detection principle. In contrast, differential absorption has advantages of simple structure, convenient use, high reliability, and the like, and is therefore widely regarded.
In contrast, a patent differential absorption type optical fiber methane gas sensor (application number: 200310108619.6) was proposed by shanghai optical precision mechanical research institute of china academy of sciences, and a sensor for detecting methane by using the same broadband light source and using an optical fiber grating as a filter to obtain a narrow-band optical signal is provided. Therefore, the device has the advantages of simple structure, low cost, elimination of the interference of background noise and the like, but the precision is not high.
The Liu Tong Yu of Shandong province academy of sciences and laser institute has proposed the mining optic fibre gas of patent and monitored the conversion equipment (application number: 200910020240.7), has given out a method of adopting the injection current of the Distributed Feedback (DFB) laser of periodic change semiconductor to control its temperature at a constant value at the same time and modulate the wavelength of the laser, and then realize the scheme of the gas monitoring conversion equipment. The detection method improves the measurement accuracy and stability, but the light intensity output by the DFB laser changes along with the change of the injection current, which brings inconvenience to the measurement and processing of back-end data.
The Chenjiu, a national treasury photoelectric technology development Limited company in Anhui province, etc. provides a distributed laser methane monitoring system (application number: 201120284513.1), which relies on a tunable semiconductor laser absorption spectrum (TDLAS) technology and utilizes an optical cable to transmit laser emitted by a DFB laser to a laser methane sensor located underground so as to acquire, analyze, process and monitor signals. The TDLAS technique also exploits the characteristic of tunable semiconductor lasers that change in output wavelength with changing injection current.
The institute of optical precision machinery, Anhui, China academy of sciences, and others have proposed a patent for an optical fiber distributed multi-point real-time gas monitor and monitoring method (application number: 200810100549.2), and a method for monitoring gas by using a harmonic detection mode is provided. The gas monitoring device adopts a near-infrared semiconductor DFB laser with the center wavelength of 1653nm as a detection light source, and superposes a 50Hz sawtooth wave signal and a 5KHz sine wave signal generated by a signal generating circuit on the driving current of the laser at the same time, so as to modulate the output wavelength of the laser and finally realize the real-time monitoring of gas. However, this method is complicated in structure and puts higher demands on the design of the circuit and the whole system.
Disclosure of Invention
The invention aims to make up for the defects of the prior art by using a temperature control semiconductor laser wavelength scanning optical fiber to measure coal mine gas.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a method for measuring coal mine gas by a temperature control semiconductor laser wavelength scanning optical fiber is characterized in that:
a. the constant current source drives the DFB laser to make the output power of the semiconductor DFB laser constant;
b. controlling the output wavelength of the semiconductor DFB laser by using a temperature scanning circuit to enable the fluctuation range of the output wavelength to be within 5 nm;
c. light output by a semiconductor DEF laser enters an input end of the optical fiber circulator, enters an air chamber through an output end, returns from the air chamber, and is output to a photoelectric detector from a reflection end of the optical fiber circulator; in the step, the light returned from the gas chamber carries the gas concentration information in the gas chamber;
d. the photoelectric detector converts the optical signal with the gas concentration information in the gas chamber into an electric signal, the A/D acquisition card acquires the electric signal, and the signal processing system calculates the gas concentration.
The center wavelength of the semiconductor DFB laser is 1653nm, and the output wavelength controlled by the temperature scanning circuit is from 1651nm to 1656 nm.
The constant current of the constant current source is 80mA, and the output power of the semiconductor DFB laser is constant at 5 mW.
The invention has the positive effects that: the semiconductor DFB laser used by the invention is driven by the constant current source, and the power of the light source can be kept stable; the temperature scanning circuit is used for controlling the output scanning changing wavelength of the semiconductor DFB laser, and the wavelength scanning range exceeding 5nm can be obtained; because the wavelength scanning detection technology is adopted, the light with the gas absorption wavelength and the light without the absorbed reference wavelength pass through the completely same transmission path, the anti-interference capability is strong, the signal-to-noise ratio is high, and the detection sensitivity is high; because the optical power is directly detected, the signal demodulation is simple, the system cost is low and the reliability is high.
Drawings
FIG. 1 is a schematic diagram of an embodiment of the present invention.
FIG. 2 is a schematic spectrum diagram of an embodiment of the present invention.
Detailed Description
Example (b):
the principle of the present invention is shown in fig. 1: the system consists of a constant current source, a semiconductor DFB laser, a temperature scanning circuit, an optical fiber circulator, an air chamber, a photoelectric detector, an A/D acquisition card and a signal processing system. The invention adopts a semiconductor DFB laser with center wavelength of 1653nm, which is driven by constant current to make the output light intensity constant, and uses a temperature scanning circuit to control the output wavelength of the laser, so that the wavelength is swept to 5nm, the light output by the laser enters an optical fiber circulator and an air chamber and returns from the air chamber, the light with gas concentration information is output to a photoelectric detector by the reflection end of the optical fiber circulator, the photoelectric detector converts the optical signal into an electric signal, then the electric signal is collected by an A/D collection card to a signal processing system, and the principle of differential absorption is used by formula
And calculating the concentration of the gas.
Wherein,
and
respectively show the wavelength of the gas absorption peak and the wavelength of the gas absorption peak,in order to emit the light intensity,
in order to be the intensity of the incident light,
which is the total efficiency of the optical path and the optoelectronic system,
is the absorption coefficient at a certain wavelength,
the length of interaction between the gas to be measured and the light,
is the gas concentration.
Because the laser is driven by the constant current source, the output light intensity is constant, then
Due to the absence of gas absorption peaks
Therefore, the concentration of the gas can be formulated
And (4) calculating.
The method comprises the following specific operation steps:
the system consists of a semiconductor DFB laser, a constant current source, a temperature scanning circuit, an optical fiber circulator, an air chamber, a photoelectric detector, an A/D acquisition card and a signal processing system. The connection relationship is as follows: the semiconductor DFB laser is driven by a constant current source, the output wavelength of the laser is controlled by a temperature scanning circuit, light output by the laser enters an input end 1 of an optical fiber circulator, an output end 2 of the optical fiber circulator is connected with an air chamber, the light is output from the output end 2 of the optical fiber circulator and returns from the air chamber through the air chamber, light with gas concentration information is output to a photoelectric detector through a reflection end 3 of the optical fiber circulator, the photoelectric detector converts an optical signal into an electric signal, the electric signal is collected to a signal processing system through an A/D (analog/digital) collection card, and finally the concentration of the gas is calculated.
The invention adopts a semiconductor DFB laser with center wavelength of 1653nm, and is driven by a constant current of 80mA to stabilize the output light power at 5mW, and a temperature scanning circuit is used for controlling the output wavelength of the laser to scan from 1651nm to 1656nm, and in the scanned 5nm range, the absorption peak wavelength of gas exists
And a very close absorption peak wavelength without gas
E.g. taking measurements
、
From the principle part, by comparisonAnd
the gas concentration can be calculated.
Claims (3)
1. A method for measuring coal mine gas by a temperature control semiconductor laser wavelength scanning optical fiber is characterized in that:
a. the constant current source drives the semiconductor DFB laser to make the output power of the semiconductor DFB laser constant;
b. controlling the output wavelength of the semiconductor DFB laser by using a temperature scanning circuit to enable the fluctuation range of the output wavelength to be within 5 nm;
c. light output by a semiconductor DEF laser enters an input end of the optical fiber circulator, enters an air chamber through an output end, returns from the air chamber, and is output to a photoelectric detector from a reflection end of the optical fiber circulator; in the step, the light returned from the gas chamber carries the gas concentration information in the gas chamber;
d. the photoelectric detector converts the optical signal with the gas concentration information in the gas chamber into an electric signal, the A/D acquisition card acquires the electric signal, and the signal processing system calculates the gas concentration.
2. A semiconductor DFB laser as claimed in claim 1 having a center wavelength of 1653nm and an output wavelength controlled by the temperature sweep circuit to sweep from 1651nm to 1656 nm.
3. The constant current source of claim 1 having a constant current of 80mA and a constant output power of 5mW for the semiconductor DFB laser.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103728270A (en) * | 2013-12-29 | 2014-04-16 | 西藏民族学院 | Method and device for detecting multi-component gas through semiconductor laser modulated spectrum |
| CN109991188A (en) * | 2018-01-02 | 2019-07-09 | 中兴通讯股份有限公司 | Gas detection method and device |
| CN111061319A (en) * | 2018-10-17 | 2020-04-24 | 北京自动化控制设备研究所 | Atomic gas chamber temperature closed-loop control method based on optical pumping saturation absorption |
| CN113865742A (en) * | 2021-08-20 | 2021-12-31 | 北京工业大学 | Method and device for measuring temperature of inner side of coated film of cavity surface of semiconductor laser based on detection optical fiber |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1945287A (en) * | 2006-10-17 | 2007-04-11 | 中国科学院安徽光学精密机械研究所 | New nodal real time gas concentration monitoring method and sensor |
| CN101251482A (en) * | 2008-03-28 | 2008-08-27 | 山东省科学院激光研究所 | Firedamp remote optical fiber laser detection instrument for mine |
| CN101514961A (en) * | 2009-03-30 | 2009-08-26 | 山东省科学院激光研究所 | Mine optical fiber gas monitoring conversion device |
| CN102662175A (en) * | 2012-05-04 | 2012-09-12 | 山东华辰泰尔信息科技股份有限公司 | Laser radar device for measuring mine gas concentration distribution and working method thereof |
-
2012
- 2012-09-19 CN CN2012103479841A patent/CN102841074A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1945287A (en) * | 2006-10-17 | 2007-04-11 | 中国科学院安徽光学精密机械研究所 | New nodal real time gas concentration monitoring method and sensor |
| CN101251482A (en) * | 2008-03-28 | 2008-08-27 | 山东省科学院激光研究所 | Firedamp remote optical fiber laser detection instrument for mine |
| CN101514961A (en) * | 2009-03-30 | 2009-08-26 | 山东省科学院激光研究所 | Mine optical fiber gas monitoring conversion device |
| CN102662175A (en) * | 2012-05-04 | 2012-09-12 | 山东华辰泰尔信息科技股份有限公司 | Laser radar device for measuring mine gas concentration distribution and working method thereof |
Non-Patent Citations (4)
| Title |
|---|
| YI JIANG, ET AL.: "An optical fiber methane sensing system employing a two-step reference measuring method", 《SENSORS AND ACTUATORS B》 * |
| 李金义: "半导体激光器的宽谱快速调谐及其在气体检测中的应用", 《中国优秀硕士学位论文全文数据库 信息科技辑》 * |
| 肖尚辉等: "基于光谱吸收型光纤传感器的煤矿瓦斯测量技术", 《光学技术》 * |
| 肖尚辉等: "基于波长扫描的差分吸收光纤煤矿瓦斯传感系统设计", 《光子学报》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103728270A (en) * | 2013-12-29 | 2014-04-16 | 西藏民族学院 | Method and device for detecting multi-component gas through semiconductor laser modulated spectrum |
| CN109991188A (en) * | 2018-01-02 | 2019-07-09 | 中兴通讯股份有限公司 | Gas detection method and device |
| CN111061319A (en) * | 2018-10-17 | 2020-04-24 | 北京自动化控制设备研究所 | Atomic gas chamber temperature closed-loop control method based on optical pumping saturation absorption |
| CN113865742A (en) * | 2021-08-20 | 2021-12-31 | 北京工业大学 | Method and device for measuring temperature of inner side of coated film of cavity surface of semiconductor laser based on detection optical fiber |
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Application publication date: 20121226 |