CN201844972U - Harmful gas concentration detector - Google Patents
Harmful gas concentration detector Download PDFInfo
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- CN201844972U CN201844972U CN2010205700375U CN201020570037U CN201844972U CN 201844972 U CN201844972 U CN 201844972U CN 2010205700375 U CN2010205700375 U CN 2010205700375U CN 201020570037 U CN201020570037 U CN 201020570037U CN 201844972 U CN201844972 U CN 201844972U
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Abstract
The utility model relates to a harmful gas concentration detector, which belongs to the technical field of optical detection. The harmful gas concentration detector comprises two groups of harmful gas concentration detection units in the same structure and an upper computer, wherein each harmful gas concentration detection unit comprises a light emitting diode (LED) light source module, an incident optical fiber, an integrating sphere gas chamber, an integrating sphere baffle plate, an photoelectric detector, a phase-lock amplifier and an emergent optical fiber, and the LED light source module comprises an LED broadband light source, a coupler, piezoceramics, an optical fiber, an optical fiber grating and an adjustable power supply. The utility model has the advantages that the harmful gas concentration detector adopts an integrating sphere optical device as an absorption gas chamber, the defects of a conventional transmission type absorption gas chamber are overcome, the longer sensing length is obtained through smaller size, in addition, the tunable wavelength LED light source is used as the incident light, and finally, the excellent algorithm is combined to realize the high-sensitivity detection of different gas concentrations.
Description
Technical field
The utility model belongs to the optical detective technology field, particularly a kind of harmful gas concentration pick-up unit.
Background technology
A large amount of methane (the CH that produce in present production, the process at coal
4) and carbon monoxide inflammable and explosive harmful gases such as (CO), brought a series of problems such as mine safety, environmental pollution.Therefore, the harmful gas concentration that produces in Coal Production, the process is carried out high-sensitivity detection and become very important.The exact instrument of measure gas concentrations mostly is optical fiber list kind gas sensor at present, the core devices that adopt conventional transmission-type absorption air chamber as fiber gas sensor more, but there is the coupled problem of optical fiber and discrete optical element in it, collimation is complicated, temperature stability is not ideal enough, the shortcoming that poor seismic behavior and accuracy of detection are not high.
Summary of the invention
At the deficiencies in the prior art, a kind of harmful gas concentration pick-up unit of the utility model as absorbing air chamber, reaches the purpose that increases sensing length by the integrating sphere optical device.
This device comprises two groups of harmful gas concentration detecting unit and host computers that structure is identical;
Described harmful gas concentration detecting unit comprises led light source module, incident optical, integrating sphere air chamber, integrating sphere baffle plate, photodetector, lock-in amplifier, outgoing optical fiber;
Wherein but the led light source module comprises LED wideband light source, coupling mechanism, piezoelectric ceramics, optical fiber, fiber grating and modulation power source; The LED wideband light source connects coupling mechanism and piezoelectric ceramics successively by optical fiber, and fiber grating is attached to the piezoelectric ceramics upper surface, but the both positive and negative polarity of modulation power source is connected to the two ends of piezoelectric ceramics;
The integrating sphere plenum surface is provided with harmful gas and detects loophole, harmful gas detection entrance port, light quantity entrance port and photodetector, wherein light quantity entrance port and harmful gas detect the two ends that loophole lays respectively at integrating sphere air chamber arbitrary diameter, light quantity exit portal and harmful gas detect the two ends that the entrance port also lays respectively at integrating sphere air chamber arbitrary diameter, and it is perpendicular that light quantity entrance port and harmful gas detect the diameter at the diameter at loophole place and light quantity exit portal and harmful gas detection place, entrance port;
Wherein the coupling mechanism in first group of led light source module is connected with the light quantity entrance port of the first group inte gration ball air chamber and the light quantity entrance port level of the second group inte gration ball air chamber respectively by incident optical, first group lock-in amplifier connects first group photodetector by optical fiber, and first group photodetector vertically is connected by the light quantity exit portal of outgoing optical fiber with the first group inte gration ball air chamber; Coupling mechanism in second group of led light source module is connected with the light quantity entrance port of the first group inte gration ball air chamber and the light quantity entrance port level of the second group inte gration ball air chamber respectively by incident optical, second group lock-in amplifier connects second group photodetector by optical fiber, and second group photodetector vertically is connected by the light quantity exit portal of outgoing optical fiber with the second group inte gration ball air chamber; First group of lock-in amplifier with second group is connected host computer simultaneously; Every group inte gration ball baffle plate is arranged on integrating sphere air chamber inside surface, and perpendicular to the tangent line of integrating sphere baffle plate and integrating sphere air chamber tie point.
The led light source module that described led light source module is a tunable wave length.
The work engineering:
In two groups of identical harmful gas concentration detecting units, the integrating sphere air chamber in first group is used as the measurement air chamber, and the integrating sphere air chamber in second group is used as reference gas chamber.And first group coupling mechanism connects first group integrating sphere air chamber and second group integrating sphere air chamber simultaneously, second group coupling mechanism connects first group integrating sphere air chamber and second group integrating sphere air chamber simultaneously, form 4 tunnel signal detection light paths, when starting first group of harmful gas concentration detecting unit, tested harmful gas detects the entrance port by harmful gas and enters first group and the second group inte gration ball air chamber, harmful gas detects loophole through harmful gas and emits, emergent light is detected and is converted to analog voltage through the light quantity exit portal by outgoing optical fiber by photodetector, the analog voltage that obtains imports computer stored into advancing analog to digital conversion through lock-in amplifier; When starting second group of harmful gas concentration detecting unit, tested harmful gas detects the entrance port by harmful gas and enters first group and the second group inte gration ball air chamber, harmful gas detects loophole through harmful gas and emits, emergent light detects and is converted to analog voltage by outgoing optical fiber by photodetector through the light quantity exit portal, the aanalogvoltage Value Data that obtains imports computing machine into advancing analog to digital conversion through lock-in amplifier, calculate with the data that first group of harmful gas concentration detecting unit is stored in the computing machine, just can detect the effective concentration value of corresponding tested harmful gas.
Advantage of the present utility model: this device has adopted the integrating sphere optical device to serve as the absorption air chamber, overcome the shortcoming that conventional transmission-type absorbs air chamber, obtain long sensing length with smaller volume, and the led light source that uses tunable wavelength is realized the high-sensitivity detection of gas with various concentration at last as incident light in conjunction with excellent algorithm.
Description of drawings
Fig. 1 is the utility model harmful gas pick-up unit structured flowchart.
Fig. 2 is the utility model harmful gas concentration detecting unit structural representation;
Fig. 3 is the led light source schematic diagram of the utility model tunable wave length;
Among the figure: 1. the led light source of tunable wave length, 2. incident optical, 3. light quantity entrance port, 4. integrating sphere baffle plate, 5. light quantity exit portal, 6. outgoing optical fiber, 7. photodetector, 8. optical fiber, 9. lock-in amplifier, 10. harmful gas detects loophole, and 11. harmful gases detect entrance port, 12. integrating sphere air chambers, 13.LED wideband light source, 14. coupling mechanisms, 15. piezoelectric ceramics, 16. fiber grating, but 17. modulation power sources.
Embodiment
The utility model further specifies in conjunction with the accompanying drawings and embodiments.
Present embodiment adopts two groups of harmful gas concentration pick-up units that harmful gas is detected, and wherein the integrating sphere air chamber 12 in first group is used as the measurement air chamber, and the integrating sphere air chamber 12 in second group is used as reference gas chamber; First group is adopted centre wavelength is 2600cm
-1The LED modulated light source; Second group is adopted centre wavelength is 3105cm
-1LED modulated light source (absorption peak of corresponding methane gas);
Wherein fiber grating is selected optical fiber Bragg raster for use; Piezoelectric ceramics 15 is selected for use mainly and is eliminated lead plumbate (PbZrO by zirconium
3-PbTiO
3) material makes; Coupling mechanism 14 is selected the AV70606 directional coupler for use; Photodetector 7 is selected HgCdTe type high-speed photodetector for use; Lock-in amplifier 9 is selected model AD630 for use; LED wideband light source 13 is selected QD-03144AR gallium arsenide phosphide type light emitting diode for use;
This device comprises two groups of harmful gas concentration detecting unit and host computers that structure is identical as shown in Figure 1;
As shown in Figure 2, every group of harmful gas concentration detecting unit includes led light source module 1, incident optical 2, integrating sphere air chamber 12, integrating sphere baffle plate 4, photodetector 7, lock-in amplifier 9 and the outgoing optical fiber 6 of tunable wave length;
As shown in Figure 3, but wherein the led light source module 1 of tunable wave length comprise LED wideband light source 13, coupling mechanism 14, piezoelectric ceramics 15, optical fiber 8, fiber grating 16 and modulation power source 17; LED wideband light source 13 connects coupling mechanism 14 and piezoelectric ceramics 15 successively by optical fiber 8, and fiber grating 16 is attached to piezoelectric ceramics 15 upper surfaces, but the both positive and negative polarity of modulation power source 17 is connected to the two ends of piezoelectric ceramics 15;
Integrating sphere air chamber 12 surfaces are provided with harmful gas and detect loophole 10, harmful gas detection entrance port 11, light quantity entrance port 3 and photodetector 7, wherein light quantity entrance port 3 detects the two ends that loophole 10 lays respectively at integrating sphere air chamber 12 arbitrary diameters with harmful gas, light quantity exit portal 5 detects the two ends that entrance port 11 also lays respectively at integrating sphere air chamber 12 arbitrary diameters with harmful gas, and light quantity entrance port 3 is perpendicular with the diameter that harmful gas detects 11 places, entrance port with diameter and light quantity exit portal 5 that harmful gas detects loophole 10 places;
Wherein the coupling mechanism in the led light source module 1 of first group of tunable wave length 14 is connected with the light quantity entrance port 3 of the first group inte gration ball air chamber 12 and light quantity entrance port 3 levels of the second group inte gration ball air chamber 12 respectively by incident optical 2, first group lock-in amplifier 9 vertically is connected by the light quantity exit portal 5 of outgoing optical fiber 6 with the first group inte gration ball air chamber 12 by the photodetector 7 that optical fiber 8 connects first group 7, the first groups of photodetectors; Coupling mechanism 14 in the led light source module 1 of second group of tunable wave length is connected with the light quantity entrance port 3 of the first group inte gration ball air chamber 12 and light quantity entrance port 3 levels of the second group inte gration ball air chamber 12 respectively by incident optical 2, second group lock-in amplifier 9 vertically is connected by the light quantity exit portal 5 of outgoing optical fiber 6 with the second group inte gration ball air chamber 12 by the photodetector 7 that optical fiber 8 connects second group 7, the second groups of photodetectors; First group of lock-in amplifier 9 with second group is connected host computer simultaneously; Every group inte gration ball baffle plate 4 is arranged on integrating sphere air chamber 12 inside surfaces, and perpendicular to the tangent line of integrating sphere baffle plate 4 with integrating sphere air chamber 12 tie points.
The course of work:
According to as shown in Figure 1, use two groups of identical harmful gas concentration detecting units, the integrating sphere air chamber 12 in first group is used as the measurement air chamber, and the integrating sphere air chamber 12 in second group is used as reference gas chamber.And first group coupling mechanism 14 connects first group integrating sphere air chamber 12 and second group integrating sphere air chamber 12 simultaneously, second group coupling mechanism 14 connects first group integrating sphere air chamber 12 and second group integrating sphere air chamber 12 simultaneously, form 4 tunnel signal detection light paths, it is 2600cm that first group of LED wideband light source 13 selected centre wavelength
-1The LED modulated light source, it is 3105cm that second group of LED wideband light source 13 selected centre wavelengths
-1The LED modulated light source, when starting first group of harmful gas concentration detecting unit, tested harmful gas detects entrance port 11 by harmful gas and enters first group and 12, the first moment of the second group inte gration ball air chamber, and centre wavelength is 2600cm in the led light source module 1 of tunable wave length
-1The LED modulated light source, enter the integrating sphere air chamber 12 of first group and second group simultaneously, because centre wavelength is 2600cm
-1The LED modulated light source avoided the absorption region of most of harmful gases, so be not subjected to the modulation of harmful gas, the disturbance of sensing light path, the influence of other gas and the drift of detection circuit have been comprised, harmful gas detects loophole 10 through harmful gas and emits, emergent light detects and is converted to analog voltage by outgoing optical fiber 6 by photodetector 7 through light quantity exit portal 5, and the analog voltage that obtains imports computer stored into advancing analog to digital conversion through lock-in amplifier 9; When starting second group of harmful gas concentration detecting unit, tested harmful gas by harmful gas detect entrance port 11 enter first group and the second group inte gration ball air chamber 12, the second constantly in the led light source module 1 of tunable wave length centre wavelength be 3105cm
-1The LED modulated light source, enter the integrating sphere air chamber 12 of first group and second group simultaneously, because centre wavelength is 3105cm
-1LED modulated light source correspondence the absorption peak of tested harmful gas, be subjected to the modulation of harmful gas, the fluctuation of signal optical source, tested gas modulation signal, harmful gas detects loophole 10 through harmful gas and emits, emergent light detects and is converted to analog voltage by outgoing optical fiber 6 by photodetector 7 through light quantity exit portal 5, the aanalogvoltage Value Data that obtains imports computing machine into advancing analog to digital conversion through lock-in amplifier 9, calculate with the data that first group of harmful gas concentration detecting unit is stored in the computing machine, computing method are as follows:
Itself just there is the light source decay in integrating sphere air chamber 12, does not promptly have under the gaseous state, and light signal intensity can reduce, and according to Lambert-Beer's law, the attenuation rate of calculated product bulb separation air chamber 12 is
, wherein
The diffuse reflectance of expression integrating sphere air chamber 12, S
2The aperture area of expression integrating sphere light quantity exit portal 5, r represents the radius of integrating sphere air chamber 12.In the present embodiment
, as calculated:
4 road signals are done following calculating:
(3)
In the formula
,
Represent that respectively centre wavelength is 2600cm
-1The outgoing light quantity of LED modulated light source flashlight by first group and the second group inte gration ball air chamber 12:
,
Represent that respectively centre wavelength is 3105cm
-1The outgoing light quantity of LED modulated light source reference light by first group and the second group inte gration ball air chamber 12; Wherein subscript x represents the parameter of reference path;
The representation signal optical wavelength;
Represent the reference light wavelength;
,
Represent that respectively centre wavelength is 2600cm
-1The incident light quantity of LED modulated light source flashlight by first group and the second group inte gration ball air chamber 12;
,
Represent that respectively centre wavelength is 3105cm
-1The incident light quantity of LED modulated light source reference light by first group and the second group inte gration ball air chamber 12;
The expression gas molecule absorbs mole coefficient;
LExpression sensing length;
CRepresent tested harmful gas concentration;
By 4 road signals having been handled formula (5):
Be approximately equal to incident intensity because of output intensity in the reference gas chamber again, but had an integrating sphere attenuation rate, so tested harmful gas concentration can be expressed as follows formula (6):
In the present embodiment outgoing light quantity of flashlight by sensing light path and reference path with through the converted proportional η of photoproduction aanalogvoltage of photodetector 7, η=0.85,
Conversion back corresponding voltage value is 0.2mv,
Conversion back corresponding voltage value is 0.8mv,
Conversion back corresponding voltage value is 0.4mv,
Conversion back corresponding voltage value is 0.5mv.
=3.8 * 10
6L/g.cm,
L=1000cm, tested as calculated harmful gas concentration
C=0.718Kg/m
3Testing result meets the technical standard requirement.
Claims (3)
1. harmful gas concentration pick-up unit, it is characterized in that: this device comprises two groups of harmful gas concentration detecting unit and host computers that structure is identical;
Described harmful gas concentration detecting unit comprises led light source module, incident optical, integrating sphere air chamber, integrating sphere baffle plate, photodetector, lock-in amplifier, outgoing optical fiber; Wherein but the led light source module comprises LED wideband light source, coupling mechanism, piezoelectric ceramics, optical fiber, fiber grating and modulation power source;
The integrating sphere plenum surface is provided with harmful gas and detects loophole, harmful gas detection entrance port, light quantity entrance port and photodetector, wherein light quantity entrance port and harmful gas detect the two ends that loophole lays respectively at integrating sphere air chamber arbitrary diameter, light quantity exit portal and harmful gas detect the two ends that the entrance port also lays respectively at integrating sphere air chamber arbitrary diameter, and it is perpendicular that light quantity entrance port and harmful gas detect the diameter at the diameter at loophole place and light quantity exit portal and harmful gas detection place, entrance port;
Wherein the coupling mechanism in first group of led light source module is connected with the light quantity entrance port of the first group inte gration ball air chamber and the light quantity entrance port level of the second group inte gration ball air chamber respectively by incident optical, first group lock-in amplifier connects first group photodetector by optical fiber, and first group photodetector vertically is connected by the light quantity exit portal of outgoing optical fiber with the first group inte gration ball air chamber; Coupling mechanism in second group of led light source module is connected with the light quantity entrance port of the first group inte gration ball air chamber and the light quantity entrance port level of the second group inte gration ball air chamber respectively by incident optical, second group lock-in amplifier connects second group photodetector by optical fiber, and second group photodetector vertically is connected by the light quantity exit portal of outgoing optical fiber with the second group inte gration ball air chamber; First group of lock-in amplifier with second group is connected host computer simultaneously; Every group inte gration ball baffle plate is arranged on integrating sphere air chamber inside surface, and perpendicular to the tangent line of integrating sphere baffle plate and integrating sphere air chamber tie point.
2. by the described harmful gas concentration pick-up unit of claim 1, it is characterized in that: the LED wideband light source connects coupling mechanism and piezoelectric ceramics successively by optical fiber in the described led light source module, fiber grating is attached to the piezoelectric ceramics upper surface, but the both positive and negative polarity of modulation power source is connected to the two ends of piezoelectric ceramics.
3. by the described harmful gas concentration pick-up unit of claim 1, it is characterized in that: the led light source module that described led light source module is a tunable wave length.
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|---|---|---|---|
| CN2010205700375U CN201844972U (en) | 2010-10-21 | 2010-10-21 | Harmful gas concentration detector |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205700375U CN201844972U (en) | 2010-10-21 | 2010-10-21 | Harmful gas concentration detector |
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| CN201844972U true CN201844972U (en) | 2011-05-25 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104596972A (en) * | 2014-12-31 | 2015-05-06 | 聚光科技(杭州)股份有限公司 | Double-light source infrared gas sensor and detection method |
| CN106338475A (en) * | 2016-08-24 | 2017-01-18 | 北京智芯微电子科技有限公司 | SF6 gas component online real-time monitoring apparatus and SF6 gas component online real-time monitoring method |
| CN108279193A (en) * | 2017-12-11 | 2018-07-13 | 中国计量大学 | Dusty gas concentration detection apparatus based on integrating sphere |
| CN109521158A (en) * | 2018-11-30 | 2019-03-26 | 安徽云汉智能科技有限公司 | A kind of combustible gas intelligent sensor |
| CN109781639A (en) * | 2019-01-31 | 2019-05-21 | 青岛海纳光电环保有限公司 | The apparatus and method of sulfur dioxide and nitrogen dioxide in surrounding air are detected simultaneously |
| CN111398203A (en) * | 2020-03-24 | 2020-07-10 | 中煤科工集团重庆研究院有限公司 | Low-power consumption methane detection device and method |
-
2010
- 2010-10-21 CN CN2010205700375U patent/CN201844972U/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104596972A (en) * | 2014-12-31 | 2015-05-06 | 聚光科技(杭州)股份有限公司 | Double-light source infrared gas sensor and detection method |
| CN106338475A (en) * | 2016-08-24 | 2017-01-18 | 北京智芯微电子科技有限公司 | SF6 gas component online real-time monitoring apparatus and SF6 gas component online real-time monitoring method |
| CN108279193A (en) * | 2017-12-11 | 2018-07-13 | 中国计量大学 | Dusty gas concentration detection apparatus based on integrating sphere |
| CN109521158A (en) * | 2018-11-30 | 2019-03-26 | 安徽云汉智能科技有限公司 | A kind of combustible gas intelligent sensor |
| CN109521158B (en) * | 2018-11-30 | 2021-06-01 | 安徽云汉智能科技有限公司 | Combustible gas intelligent sensor |
| CN109781639A (en) * | 2019-01-31 | 2019-05-21 | 青岛海纳光电环保有限公司 | The apparatus and method of sulfur dioxide and nitrogen dioxide in surrounding air are detected simultaneously |
| CN109781639B (en) * | 2019-01-31 | 2024-01-30 | 青岛崂应海纳光电环保集团有限公司 | Device and method for simultaneously detecting sulfur dioxide and nitrogen dioxide in ambient air |
| CN111398203A (en) * | 2020-03-24 | 2020-07-10 | 中煤科工集团重庆研究院有限公司 | Low-power consumption methane detection device and method |
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Granted publication date: 20110525 Termination date: 20121021 |