CN103743706A - Full-scale range high-sensitive gas detecting method and apparatus - Google Patents
Full-scale range high-sensitive gas detecting method and apparatus Download PDFInfo
- Publication number
- CN103743706A CN103743706A CN201310656495.9A CN201310656495A CN103743706A CN 103743706 A CN103743706 A CN 103743706A CN 201310656495 A CN201310656495 A CN 201310656495A CN 103743706 A CN103743706 A CN 103743706A
- Authority
- CN
- China
- Prior art keywords
- signal
- concentration
- methane gas
- laser instrument
- circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The invention discloses a full-scale range high-sensitive gas detecting method. According to the full-scale range high-sensitive gas detecting method, (1) a laser is driven by a constant current source, and is driven by superposed periodically discontinuous high frequency sine wave signal A and low frequency sawtooth signal B; (2) optical signals outputted by the laser are transmitted into a sensing air chamber, and are converted into electric signals via a photoelectric detector; and (3) the electric signals are divided into two parts for processing, one part is subjected to amplification and lowpass filtering processing successively, and then is subjected to direct sampling analysis processing via A/D conversion, and the other part is subjected to lock-in amplification, and sampling analysis processing via A/D conversion. The invention also discloses a full-scale range high-sensitive gas detecting apparatus comprising the laser, the constant current source, a microprocessor, a signal producing circuit, a drive circuit, the sensing air chamber, the photoelectric detector, a lock-in amplifier, and a high concentration detection module. The full-scale range high-sensitive gas detecting method and the apparatus are capable of solving a problem that sensitivity and detection range are suppressed by each other in traditional spectral absorption gas detecting method and apparatus, and realizing full-scale range high-sensitive gas concentration detection, and possess significant importance on safety monitoring of coal mines.
Description
Technical field
The invention belongs to the detection of gas concentration in detection field, refer to particularly a kind of gamut high sensitivity methane gas detection method and device.
Background technology
Along with industrial expansion, coal becomes the requisite energy, but coal mining accident also constantly occurs simultaneously.Gas explosion accident, as one of important threat of Safety of Coal Mine Production, frequently occurs in recent years, and therefore, detecting in real time, exactly methane gas concentration has important society and economic implications to Safety of Coal Mine Production and people life property safety.
Mine gas be mainly coal-seam gas form take methane as main harmful gas, the easily accident such as explosion caused and personnel's death by suffocation.Gassy mine is generally taked to the measure of closing down abroad, and China is serious due to coal is relied on, and in the management of colliery, still has many imperfection parts, many gassy mines are still for coal mining.In existing methane Concentration Measurement means, what generally adopt is the firedamp sensor based on thermocatalysis principle, but this sensor exists the shortcomings such as little, easy generation " poisoning " phenomenon of measurement range and adjustment difficulty.In addition, also has catalytic combustion type gas sensor, when but it meets the impact of high concentration methane, the activity (sensitivity) of element can change, cause read untrue, and have the ambiguity of output, when Methane in Air content is greater than 10%, oxygen concentration declines, cause methyl hydride combustion incomplete, output valve reduces, and occurs that two kinds of different concentration of methane gas export the phenomenon of same signal.If it will be very dangerous that high concentration is mistaken for to low concentration.
Tunable diode laser absorption spectroscopy technology, as current widely used a kind of spectral absorption type gas detection technology, is to utilize the length scanning of semiconductor laser and a kind of technology that electric current tuning characteristic is measured trace gas.Due to the high monochromaticity of semiconductor laser, therefore can utilize an isolated absorption line of gas molecule to measure the absorption spectrum of gas, thereby from composite pollution composition, identify different molecules easily, avoid the interference of spectrum.Compared with traditional sensors, that tunable laser absorption spectroscopy techniques has is highly sensitive, distinguishing ability strong, stability advantages of higher, has represented the developing direction of gas detection technology.But the absorption firedamp sensor of common spectrum, when doing gamut detection, exists the restriction of detection sensitivity and sensing range, that is: when carrying out the detection of gamut concentration, be difficult to meet the sensitivity requirement that low concentration gas detects; When carrying out low concentration high-sensitivity detection, because making high concentration gas, cannot measure limiting voltage again.
Summary of the invention
Technical matters to be solved by this invention is just to provide a kind of gamut high sensitivity methane gas detection method and device, can overcome the mutual restriction that existing spectral absorption formula gas detects medium sensitivity and sensing range, the high sensitivity methane gas concentration that realizes gamut detects, significant to the safety monitoring in colliery.
For solving the problems of the technologies described above, a kind of gamut high sensitivity methane gas detection method provided by the invention, comprises the steps:
1) laser instrument is driven by constant current source, and signal A and signal B stack rear drive laser instrument, modulate the output wavelength of laser instrument, makes Absorption Line of centre wavelength and methane of laser instrument output consistent; Described signal A is the high_frequency sine wave of cycle discontinuity, signal B is low frequency sawtooth wave, signal after stack is divided into rising and decline two parts in one-period, only rising part is superimposed with high_frequency sine wave, methane gas concentration while being used for measuring low concentration, methane gas concentration when sloping portion is used for measuring high concentration;
2) light signal of laser instrument output is sent into sensing air chamber, through the light signal of sensing air chamber, through photodetector, is converted to electric signal;
3) electric signal after photodetector conversion being divided into two-way processes: a road is successively through amplifying, after low-pass filtering treatment, change Direct Sampling analyzing and processing by A/D, the methane gas concentration information when obtaining high concentration; Sampling analysis processing, after phase-locked amplification is processed, is changed by A/D in another road, the methane gas concentration information when obtaining low concentration.
In the described step 3) of technique scheme, the concrete operations of phase-locked amplification processing are: first this road electric signal amplifies, high-pass filtering processing, become x (t) signal, after x (t) signal and r (t) signal multiply each other in multiplier circuit, carry out low-pass filtering, amplify and process; Described r (t) signal is the square-wave signal of x (t) signal two frequencys multiplication, and x (t) signal is just two cycles of corresponding r (t) signal in each cycle of x (t) signal with the phase place of r (t) signal.
In the described step 3) of technique scheme, the critical value setting of high concentration and low concentration is volumetric concentration 4～10%.
A kind of gamut high sensitivity methane gas pick-up unit provided by the invention, comprises laser instrument, constant current source, microprocessor, signal generating circuit, driving circuit, sensing air chamber, photodetector, lock-in amplifier and high concentration detection module; Described constant current source is connected with laser instrument, tuning for laser instrument; Described microprocessor, signal generating circuit, driving circuit and laser instrument are connected successively, for generation of after the high_frequency sine wave signal A of cycle discontinuity and low frequency sawtooth signal B and stack, the output wavelength of laser instrument being modulated; The output terminal of described laser instrument is connected with sensing air chamber and photodetector by optical fiber successively, is respectively used to realize absorption and the opto-electronic conversion of methane gas to light; The output terminal of described photodetector is connected with lock-in amplifier and high concentration detection module respectively, methane gas concentration information when the methane gas concentration information while being respectively used to obtain low concentration and high concentration, the signal output part of lock-in amplifier and high concentration detection module is connected with described microprocessor respectively, for signal, processes and shows.
In technique scheme, described lock-in amplifier comprises successively and to connect:
The first amplifying circuit, for amplifying the output signal of photodetector;
High-pass filtering circuit, for filtering low frequency signal;
Multiplier circuit, its another input end is connected with an output terminal of described microprocessor, for two frequency multiplication square-wave signal r (t) of x (t) signal of x (t) signal producing after amplification, high-pass filtering and microprocessor generation are multiplied each other;
The first low-pass filter circuit, for filtering high-frequency signal;
The second amplifying circuit, for the signal after amplification low pass;
And the 2nd ADC Acquisition Circuit, for A/D, change and export to microprocessor.
In technique scheme, described high concentration detection module comprises successively and to connect:
The 3rd amplifying circuit, for amplifying the output signal of photodetector;
The second low-pass filter circuit, for filtering high-frequency signal;
And an ADC Acquisition Circuit, for A/D, change and export to microprocessor.
Compared with prior art, utilize the inventive method and device: when tested concentration of methane gas is higher, can directly by the mode of amplification filtering, detect gas concentration; When tested concentration of methane gas is lower, methane gas is very faint to the absorption of light signal, by the mode of phase-locked amplification, detects gas concentration, thereby has realized the detection of gamut high sensitivity methane gas.The present invention realizes the dual-use function of high concentration and low-concentration methane gas being made to Measurement accuracy, and highly sensitive, distinguishing ability strong, good stability.
Accompanying drawing explanation
Fig. 1 is structured flowchart and the fundamental diagram of an embodiment of gamut high sensitivity methane gas pick-up unit of the present invention;
Fig. 2 is the drive waveforms figure of laser instrument in Fig. 1.
Embodiment
Below in conjunction with accompanying drawing, specific embodiments of the invention are described in further detail:
As depicted in figs. 1 and 2, a kind of gamut high sensitivity methane gas pick-up unit provided by the invention, comprises laser instrument, constant current source, microprocessor, signal generating circuit, driving circuit, sensing air chamber, photodetector, lock-in amplifier and high concentration detection module.Constant current source is connected with laser instrument, tuning for laser instrument.Microprocessor, signal generating circuit, driving circuit and laser instrument are connected successively, for generation of after the high_frequency sine wave signal A of cycle discontinuity and low frequency sawtooth signal B and stack, the output wavelength of laser instrument being modulated.The output terminal of laser instrument is connected with sensing air chamber and photodetector by optical fiber successively, is respectively used to realize absorption and the opto-electronic conversion of methane gas to light.The output terminal of photodetector is connected with lock-in amplifier and high concentration detection module respectively, methane gas concentration information when the methane gas concentration information while being respectively used to obtain low concentration and high concentration, the signal output part of lock-in amplifier and high concentration detection module is connected with microprocessor respectively, for signal, processes and shows.Wherein, lock-in amplifier comprises the first amplifying circuit, high-pass filtering circuit, multiplier circuit, the first low-pass filter circuit, the second amplifying circuit and the 2nd ADC Acquisition Circuit that connect successively, and another input end of multiplier circuit is also connected with an output terminal of aforementioned microprocessor; High concentration detection module comprises the 3rd amplifying circuit, the second low-pass filter circuit and the ADC Acquisition Circuit that connect successively.
The step of utilizing this device to carry out the detection of gamut high sensitivity methane gas is:
1) low frequency sawtooth signal B is produced by microprocessor, by timer internal, is triggered, and frequency is accurately adjustable, and the frequency of signal B is tens of to hundreds of hertz conventionally; High_frequency sine wave signal A is interrupted and is produced square wave and obtain afterwards through quadravalence Butterworth LPF by microprocessor, and frequency is generally tens of megahertzes.Laser instrument is driven by constant current source, after signal A and signal B stack, becomes signal C drive laser, and the output wavelength of laser instrument is modulated, and makes Absorption Line of centre wavelength and methane of laser instrument output consistent.The drive current of laser instrument must be adjusted at a suitable scope, allow as far as possible laser works in linear zone, be conducive to find absorption peak and improve to-noise ratio.As shown in Figure 2, the signal C forming after stack is divided into and rises and decline two parts within each cycle, and only rising part is superimposed with high_frequency sine wave, the methane gas concentration when measuring low concentration, sloping portion is overlapped high-frequency sine wave not, the methane gas concentration when measuring high concentration;
2) light signal of laser instrument output is sent into sensing air chamber, through the light signal of sensing air chamber, through photodetector, is converted to electric signal, in practical operation, should make photodetector be operated in linear zone as far as possible;
When concentration of methane gas detected in sensing air chamber is higher, light beam is converted to after electric signal by methane gas again, through amplifying and filtering processing, can obtain obvious absorption peak, as shown in the sloping portion of signal E in Fig. 2, adopt respective algorithms to calculate the amplitude of absorption peak, just can obtain gas concentration value; When concentration of methane gas detected in sensing air chamber is lower, as shown in the sloping portion of signal D in Fig. 2, light beam is converted to after electric signal by methane gas again, and absorption peak is very faint, can not, by direct-detection, therefore adopt Technique of Weak Signal Detection.
When detected concentration of methane gas is very low, to the absorption of light also just very a little less than, due to external interference, the noise of sensor itself and the noise of metering circuit etc., useful signal is flooded by a large amount of interference and noise.The object of Detection of Weak Signals is exactly to measure the feeble signal being covered by ground unrest, after processing, can use directly to A/D change-over circuit through suitable amplification filtering.Be characterized in that detection sensitivity is high, signal to noise ratio (S/N ratio) is very high.Ultimate principle is uncorrelated with noise, noise and signal based on noise, complete dependence of signal and signal.According to this characteristic, the computing cross-correlation of circuit settling signal and reference signal, thus the signal amplitude in very noisy and phase information are detected.The present invention adopts the mode of phase-locked amplification, and concrete operations are as following;
3) electric signal after photodetector conversion being divided into two-way processes: a road is successively through amplifying, after low-pass filtering treatment, change Direct Sampling analyzing and processing by A/D, the methane gas concentration information when obtaining high concentration; Sampling analysis processing, after phase-locked amplification is processed, is changed by A/D in another road, the methane gas concentration information when obtaining low concentration.
The concrete operations of phase-locked amplification processing are: as shown in Figure 1, first this road electric signal amplifies, high-pass filtering processing, become modulated x (t) signal, r (t) signal is produced by microprocessor, for the square-wave signal of x (t) signal two frequencys multiplication, and x (t) signal and the phase place of r (t) signal are adjusted to just two cycles of corresponding r (t) signal in each cycle of x (t) signal.After x (t) signal and r (t) signal multiply each other in multiplier circuit, carry out low-pass filtering, because the amplitude of useful signal is very little, be low to moderate several millivolts even a little, thus also need to amplify processing, then send into A/D conversion.
In the present embodiment, the critical value setting of methane gas high concentration and low concentration is volumetric concentration 4%.For concentration lower than 4% methane gas, when the maximum voltage of 12 ADC Acquisition Circuit is 2.5V, the voltage magnitude that the methane gas that is 4% through concentration by spectrum absorbs after processing is amplified to 2.5V, magnitude of voltage corresponding to methane gas that now concentration is 4% is 2.5V, the voltage minimum resolution of 12 ADC Acquisition Circuit is 0.61mV, and the minimum resolution that detects in theory concentration of methane gas can arrive 10ppm.For concentration, higher than 4% methane gas, be equally also 12 ADC Acquisition Circuit, reference voltage is 2.5V.The absorption peak of the methane gas that is 100% by concentration is amplified to 2.5V, magnitude of voltage corresponding to methane gas that concentration is 100% is so 2.5V, magnitude of voltage corresponding to methane gas that now concentration is 4% should be 100mV, and now minimum resolution can reach 244ppm in theory.Therefore, whole device can be realized the detection sensitivity of about 10ppm when low concentration (being less than or equal to 4%), realizes the detection of 100% concentration gamut when high concentration (being greater than 4%).
In practical operation, when each measurement, first microprocessor need judge the concentration range of tested gas: if the voltage magnitude of an ADC Acquisition Circuit exceedes 100mV, the 2nd ADC Acquisition Circuit is closed, utilize the signal of an ADC Acquisition Circuit collection to carry out Treatment Analysis, the methane gas concentration information while obtaining high concentration; If the voltage magnitude of an ADC Acquisition Circuit is no more than 100mV, the 2nd ADC Acquisition Circuit is opened, and utilizes the signal of the 2nd ADC Acquisition Circuit collection to carry out Treatment Analysis, the methane gas concentration information while obtaining low concentration.
The power supply of whole device is 9～36V, and constant current source is selected the switch power module of 4:1 wide cut input, and with respect to linear power supply, its volume is little, efficiency is high, easy to use.The amplifier of signal processing is selected low-power consumption, low noise, rail-to-rail amplifier, and uses single supply op as far as possible.In order to limit the surge current of powered on moment, at a NTC(thermistor of installation's power source line input series connection), when cold start-up, NTC presents high impedance, thereby will make inrush current be limited.And when the thermal effect of electric current sharply declines the rising of NTC temperature, resistance, the current limit effect of system is reduced.Meanwhile, because NTC is not zero in the impedance under hot, thus can produce power attenuation, thus the operational efficiency of system affected.While restarting under NTC is hot, surge current is not had to restriction.For this reason, system start after, can utilize SCR(controllable silicon) etc. element by NTC short circuit.
This device can make full use of function of the MCU, comprises DMA(direct memory access), timer, ADC, DAC.Wherein, the data transmission of ADC and DAC all completes with DMA, and not only transmission speed is fast, and does not take CPU time, is more conducive to the data processing in CPU later stage.The methane gas concentration amplitude gathering is carried out to multiple averaging, can further improve to-noise ratio.By Infrared remote controller is set, can teach zero to methane gas sensor, concentration calibration.
Core of the present invention is to have distinguished high-concentration and low-concentration, when tested concentration of methane gas is higher, can directly by the mode of amplification filtering, detect gas concentration; When tested concentration of methane gas is lower, methane gas is very faint to the absorption of light signal, by the mode of phase-locked amplification, detects gas concentration, thereby has realized the detection of gamut high sensitivity methane gas.So its protection domain is not limited to above-described embodiment.Obviously, those skilled in the art can carry out various changes and distortion and not depart from the scope of the present invention and spirit the present invention.For example: the critical value of high concentration and low concentration is not limited to 4% in embodiment, in 4～10% scopes, be all feasible etc.If these changes and distortion belong in the scope of the claims in the present invention and equivalent technologies thereof, the present invention is also intended to comprise these changes and is out of shape interior.
Claims (6)
1. a gamut high sensitivity methane gas detection method, is characterized in that, comprises the steps:
1) laser instrument is driven by constant current source, and signal A and signal B stack rear drive laser instrument, modulate the output wavelength of laser instrument, makes Absorption Line of centre wavelength and methane of laser instrument output consistent; Described signal A is the high_frequency sine wave of cycle discontinuity, signal B is low frequency sawtooth wave, signal after stack is divided into rising and decline two parts in one-period, only rising part is superimposed with high_frequency sine wave, methane gas concentration while being used for measuring low concentration, methane gas concentration when sloping portion is used for measuring high concentration;
2) light signal of laser instrument output is sent into sensing air chamber, through the light signal of sensing air chamber, through photodetector, is converted to electric signal;
3) electric signal after photodetector conversion being divided into two-way processes: a road is successively through amplifying, after low-pass filtering treatment, change Direct Sampling analyzing and processing by A/D, the methane gas concentration information when obtaining high concentration; Sampling analysis processing, after phase-locked amplification is processed, is changed by A/D in another road, the methane gas concentration information when obtaining low concentration.
2. gamut high sensitivity methane gas detection method according to claim 1, it is characterized in that: in described step 3), the concrete operations of phase-locked amplification processing are: first this road electric signal amplifies, high-pass filtering processing, become x (t) signal, after x (t) signal and r (t) signal multiply each other in multiplier circuit, carry out low-pass filtering, amplify and process; Described r (t) signal is the square-wave signal of x (t) signal two frequencys multiplication, and x (t) signal is just two cycles of corresponding r (t) signal in each cycle of x (t) signal with the phase place of r (t) signal.
3. gamut high sensitivity methane gas detection method according to claim 1 and 2, is characterized in that: in described step 3), the critical value setting of high concentration and low concentration is volumetric concentration 4～10%.
4. a gamut high sensitivity methane gas pick-up unit, is characterized in that: comprise laser instrument, constant current source, microprocessor, signal generating circuit, driving circuit, sensing air chamber, photodetector, lock-in amplifier and high concentration detection module; Described constant current source is connected with laser instrument, tuning for laser instrument; Described microprocessor, signal generating circuit, driving circuit and laser instrument are connected successively, for generation of after the high_frequency sine wave signal A of cycle discontinuity and low frequency sawtooth signal B and stack, the output wavelength of laser instrument being modulated; The output terminal of described laser instrument is connected with sensing air chamber and photodetector by optical fiber successively, is respectively used to realize absorption and the opto-electronic conversion of methane gas to light; The output terminal of described photodetector is connected with lock-in amplifier and high concentration detection module respectively, methane gas concentration information when the methane gas concentration information while being respectively used to obtain low concentration and high concentration, the signal output part of lock-in amplifier and high concentration detection module is connected with described microprocessor respectively, for signal, processes and shows.
5. gamut high sensitivity methane gas pick-up unit according to claim 4, is characterized in that, described lock-in amplifier comprises successively and to connect:
The first amplifying circuit, for amplifying the output signal of photodetector;
High-pass filtering circuit, for filtering low frequency signal;
Multiplier circuit, its another input end is connected with an output terminal of described microprocessor, for two frequency multiplication square-wave signal r (t) of x (t) signal of x (t) signal producing after amplification, high-pass filtering and microprocessor generation are multiplied each other;
The first low-pass filter circuit, for filtering high-frequency signal;
The second amplifying circuit, for the signal after amplification low pass;
And the 2nd ADC Acquisition Circuit, for A/D, change and export to microprocessor.
6. according to the gamut high sensitivity methane gas pick-up unit described in claim 4 or 5, it is characterized in that, described high concentration detection module comprises successively and to connect:
The 3rd amplifying circuit, for amplifying the output signal of photodetector;
The second low-pass filter circuit, for filtering high-frequency signal;
And an ADC Acquisition Circuit, for A/D, change and export to microprocessor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310656495.9A CN103743706A (en) | 2013-12-06 | 2013-12-06 | Full-scale range high-sensitive gas detecting method and apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310656495.9A CN103743706A (en) | 2013-12-06 | 2013-12-06 | Full-scale range high-sensitive gas detecting method and apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103743706A true CN103743706A (en) | 2014-04-23 |
Family
ID=50500744
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310656495.9A Pending CN103743706A (en) | 2013-12-06 | 2013-12-06 | Full-scale range high-sensitive gas detecting method and apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103743706A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105891151A (en) * | 2016-04-21 | 2016-08-24 | 中国科学院长春光学精密机械与物理研究所 | Single-light-source laser drive system for reflection type laser drunk driving detection |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| JP2009192246A (en) * | 2008-02-12 | 2009-08-27 | Fuji Electric Systems Co Ltd | Instrument for measuring gas concentration, and method of measuring gas concentration |
| JP2010048639A (en) * | 2008-08-21 | 2010-03-04 | Fuji Electric Systems Co Ltd | Laser type gas analyzer and method for measuring gas concentration |
| CN101782514A (en) * | 2009-11-05 | 2010-07-21 | 胜利油田胜利工程设计咨询有限责任公司 | Online monitoring device for concentration of hydrogen sulfide by laser |
| CN102346133A (en) * | 2010-08-06 | 2012-02-08 | 北京大方科技有限责任公司 | Coalmine gas monitoring device and method |
| CN202522514U (en) * | 2012-05-07 | 2012-11-07 | 重庆飞尔达机械有限责任公司 | Coal-mine gas monitoring system based on spectral absorption |
| JP2012220250A (en) * | 2011-04-05 | 2012-11-12 | Shimadzu Corp | Gas concentration measuring apparatus and gas concentration measuring method |
-
2013
- 2013-12-06 CN CN201310656495.9A patent/CN103743706A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009192246A (en) * | 2008-02-12 | 2009-08-27 | Fuji Electric Systems Co Ltd | Instrument for measuring gas concentration, and method of measuring gas concentration |
| JP2010048639A (en) * | 2008-08-21 | 2010-03-04 | Fuji Electric Systems Co Ltd | Laser type gas analyzer and method for measuring gas concentration |
| 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 |
| CN101782514A (en) * | 2009-11-05 | 2010-07-21 | 胜利油田胜利工程设计咨询有限责任公司 | Online monitoring device for concentration of hydrogen sulfide by laser |
| CN102346133A (en) * | 2010-08-06 | 2012-02-08 | 北京大方科技有限责任公司 | Coalmine gas monitoring device and method |
| JP2012220250A (en) * | 2011-04-05 | 2012-11-12 | Shimadzu Corp | Gas concentration measuring apparatus and gas concentration measuring method |
| CN202522514U (en) * | 2012-05-07 | 2012-11-07 | 重庆飞尔达机械有限责任公司 | Coal-mine gas monitoring system based on spectral absorption |
Non-Patent Citations (2)
| Title |
|---|
| 李政颖等: "光纤气体传感器解调方法的研究", 《物理学报》 * |
| 李政颖等: "光谱吸收式全量程甲烷检测技术的研究", 《武汉理工大学学报》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105891151A (en) * | 2016-04-21 | 2016-08-24 | 中国科学院长春光学精密机械与物理研究所 | Single-light-source laser drive system for reflection type laser drunk driving detection |
| CN105891151B (en) * | 2016-04-21 | 2019-10-25 | 中国科学院长春光学精密机械与物理研究所 | A kind of single light source Laser Driven system for reflective laser drunk driving detection |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN205374298U (en) | Trace gas concentration detection apparatus based on TDLAS | |
| CN101435773B (en) | Gas monitoring method and apparatus based on quasi continuous diode laser modulated spectrum | |
| CN202974860U (en) | High-precision infrared gas detection module | |
| CN101592602B (en) | Infrared gas senor system with high sensitivity and high stability | |
| CN201575308U (en) | Tunnel open space natural gas leakage laser monitoring device | |
| CN103017991B (en) | Suction type SF6 gas leakage monitoring method | |
| CN102608064B (en) | Three-channel infrared gas sensor for CO gas high-precision detection | |
| CN102914519A (en) | Optical fiber type laser liquid turbidity measuring device and measuring method | |
| CN203324179U (en) | High-sensitivity portable gas detection instrument based on NDIR (Non-Dispersive Infra-Red) principle | |
| CN202939125U (en) | Coal mine gas concentration infrared detection device | |
| CN111007025A (en) | Detection device capable of detecting and displaying three concentrations of methane gas | |
| CN103969209A (en) | Concentration sensor | |
| CN105158205A (en) | Method and device for remotely measuring methane concentration by methane gas mass interface recognition and laser with adjustable measuring range | |
| CN204855369U (en) | Methane gas concentration detection device based on multimode laser spectrum technology | |
| CN103528991B (en) | System and method for measuring organic matter content of soil | |
| CN103364365A (en) | WSN (Wireless Sensor Network) sensor node for natural gas content in air | |
| CN204008440U (en) | The signal processing apparatus and the gas detecting system thereof that detect for difference gas | |
| CN107478601A (en) | Gas concentration detection system and detection method based on Wavelength modulation spectroscopy | |
| CN203534957U (en) | Aerosol optical absorption coefficient detection device based on photoacoustic spectrum | |
| CN105021568A (en) | Methane gas concentration detection device based on multi-mode laser spectrum technology | |
| CN103411902A (en) | Wide-range micro-water measuring system based on programmable amplifier | |
| CN103743706A (en) | Full-scale range high-sensitive gas detecting method and apparatus | |
| CN102841074A (en) | Method for measuring coal mine gas by using laser wavelength scanning optical fiber of temperature control semiconductor | |
| CN203688440U (en) | Nons-splitting infrared gas detector | |
| CN203191309U (en) | Concentration sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20140423 |