WO2013010984A2 - Device for detecting trace gases - Google Patents
Device for detecting trace gases Download PDFInfo
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- WO2013010984A2 WO2013010984A2 PCT/EP2012/063897 EP2012063897W WO2013010984A2 WO 2013010984 A2 WO2013010984 A2 WO 2013010984A2 EP 2012063897 W EP2012063897 W EP 2012063897W WO 2013010984 A2 WO2013010984 A2 WO 2013010984A2
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- analysis cell
- laser
- laser emission
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- cell
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/02—Mechanical
- G01N2201/021—Special mounting in general
- G01N2201/0216—Vehicle borne
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/02—Mechanical
- G01N2201/023—Controlling conditions in casing
- G01N2201/0231—Thermostating
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/02—Mechanical
- G01N2201/023—Controlling conditions in casing
- G01N2201/0233—Gas purge
Definitions
- the present invention relates to a device for detecting traces of gas. It applies, in particular, to the detection of traces of gases representative of air pollution or danger on a site.
- the present invention aims to remedy these disadvantages.
- the present invention aims a gas trace detection device which comprises, in a closed box:
- an analysis cell provided with input and output means for air samples
- a laser emission source which emits a laser beam to said analysis cell
- a main photosensitive sensor positioned to receive the laser beam coming out of said analysis cell and adapted to emit a signal representative of the light intensity received by said sensor
- a means of maintaining a temperature adapted to maintain at a constant predetermined temperature jointly:
- the device is autonomous and does not need re-calibration.
- the device can be miniaturized to fit in a vehicle, for example a van to continuously take ambient air and accurately map the traces of gas detected.
- the laser emission source is of the quantum cascade laser type ("QCL” or “Quantum Cascade Laser”).
- Quantum cascade laser technology offers a range of lasers in the mid-infrared that makes wavelengths characteristic of a very large set of complex molecules accessible.
- the device of the present invention further comprises a visible laser and a mirror support adapted to reflect the laser beam from the visible laser on the optical path of the laser emission source.
- This visible laser makes it possible, thanks to a removable mirror positioned on the optical path of the laser emission source, to visualize the optical path and to correctly position the mirrors and the analysis cell.
- the box is a waterproof box lined with thermal foam inside.
- the device that is the subject of the invention comprises a bottle of pressurized dry air whose outlet is connected to the inside of the box.
- This bottle of dry air makes it possible to purge the gas, and therefore the humidity, in the box.
- the device of the invention comprises, inside the box, at least one fan supported through the optical bench.
- the transmission of the vibrations of the fan to the optical elements is reduced. Indeed, the skilled person is discouraged to provide a fan near elements of an optical bench, both the first is a source of vibration and the second must be protected from vibration.
- the vibrations of the fan are transmitted to a support without passing through the optical bench.
- the temperature-maintaining means comprises a heat exchanger putting into temperature, by thermal conduction, said optical bench.
- the device which is the subject of the invention comprises means for pumping air present in the analysis cell.
- the sample gas is pumped out to maintain the analysis cell under low pressure.
- At least one solenoid valve placed upstream of the analysis cell, is slaved to a pressure measurement at the input of the analysis cell, the opening of the solenoid valve causing a variation of the pressure at the inlet of the solenoid valve. inside the analysis cell.
- part of the light emitted by the laser emission source reflected on the transparent surface at the input of the analysis cell is received, via a germanium bar, by a secondary photosensitive sensor .
- the output signal of this secondary photosensitive sensor serves as the transmission reference of the laser emission source.
- FIG. 1 represents, schematically and in plan view, a particular embodiment of the device that is the subject of the present invention
- FIG. 2 schematically and in plan view, the device of FIG. 1 after removal of a heat exchanger
- FIG. 3 is a diagrammatic side view of the device illustrated in FIGS. 1 and 2 and
- FIG. 4 illustrates, in the form of a logic diagram, steps of the method for implementing the device illustrated in FIGS. 1 to 3.
- the device 102 which is the subject of the invention comprises three main parts:
- the treatment portion of the air sample comprises:
- a pump pumps the sample air at the outlet of the pipe 142.
- the analysis cell 1 1 2 is of the aerodyne type with toroidal mirrors. By injecting a laser beam on a predetermined input axis, this ray travels exactly 76 meters before emerging from the analysis cell.
- the sample air passage tubes 122 make the air sample travel four times the length of a heat exchanger 120.
- the filter 34 is of known type.
- the solenoid valve 136 is slaved to the pressure measured by the incoming air pressure sensor 140. The pressure inside the cell is thus maintained at 40 mbar +/- 4 10 -3 mbar.
- the thermal part comprises:
- the box 104 is waterproof. It is, preferably painted white, to limit radiation and doubled, inside, a thermal foam.
- the heat exchangers 120 and 166 have different functions. Connected to the same source of thermalization water, the first thermalizes, by convection, the air constituting the sample and the second thermalizes, by conduction, the optical bench 1 18. It is noted that the inlet and outlet pipes, in particular those of the exchanger 166, are not shown in FIG.
- the radiator 1 30 and the two fans 132 associated with it heat the ambient air in the box 104. It is observed that the main source of laser emission 1 06 is also thermalized by the water thermalization circuit, by through pipes 124.
- the temperature of the thermalization water is controlled by the signals output from the air temperature sensors in the casing 144 and 146 and the sample air inlet and outlet temperature sensors 148 and 150.
- the air in the sample and the ambient air in the chamber 104 are thus maintained at a temperature of 25 ° C + / - 15 October 3 C.
- the optical part comprises:
- the main source of laser emission 106 is of the quantum cascade laser type ("QCL” or "Quantum Cascade Laser”).
- Quantum cascade laser technology offers a range of lasers in the mid-infrared that makes wavelengths characteristic of a very large set of complex molecules accessible.
- a main optical path of entry of laser beams into the cell 1 12 comprises the laser source 106, provided with an optic, the mirror 108 and the mirror 154.
- a removable planar mirror (not shown) is positioned on the support 1 16, a visible laser beam emitted by the secondary source 1 14 is reflected on this mirror and follows, then, the same optical path as the laser beam from the main source 1 06.
- the laser beam is reflected on the mirror 152 and reaches the main photosensitive sensor 1 56. This provides a signal representative of the light energy absorption in the sample. air present in the analysis cell 1 1 2.
- the optical signal emitted by the The photosensitive sensor 1 10 serves as a reference for the calibration of the output signal of the photosensitive sensor 156. This feedback loop makes it possible to avoid servocontrolling the laser.
- the signals from the photosensitive sensors 10 and 156 make it possible to determine with great sensitivity and precision the proportion of traces of a gas absorbing the wavelength emitted by the source 106 in the sample. For this purpose, we implement the law of Bert-Lambert.
- the device 102 comprises:
- the device 102 comprises, inside the box 104, at least one fan 132 supported through the optical bench 1 18. Supporting each fan 1 32, through openings in the optical bench 1 18, the vibrations of this fan 132 is transmitted to a support without passing through the optical bench 1 18.
- each fan 132 is supported by the support of the exchanger 130. The separation of the support of the exchanger 130, which carries the fans 1 32 and the support of the optical bench 1 18, as well as the presence of silent blocks between them makes it possible to reduce the vibrations of the optical bench 1 18.
- a bottle of pressurized dry air (not shown) makes it possible to purge the gas (and thus the moisture) in the well 1 04 and in the analysis cell 1 12.
- the applications of the present invention include the detection of:
- a first stage 200 of operation is carried out first, that is to say, in particular powering the components and elements of the device 102. Then, during a step 205, it is expected that the device 1 02 reaches its thermal equilibrium, as a function of the representative signals of heat leaving the sensors 144 to 1 50 and data learning. During a step 210, the well 104 and the analysis cell 112 are purged with the contents of the pressurized dry air bottle.
- the laser emission source 106 is turned on.
- an air sample is taken.
- the device 102 can be mounted on a vehicle, the sampling can be continuous and geolocated.
- the light intensity received by the photosensitive sensor 156. is measured.
- the light intensity received by the photosensitive sensor 1 10 is measured.
- the concentration in the sample air of a molecule which absorbs the wavelength emitted by the source 106 is determined. Then, step 220 is returned.
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- Spectroscopy & Molecular Physics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
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- Investigating Or Analysing Materials By Optical Means (AREA)
- Optical Measuring Cells (AREA)
Abstract
Description
DISPOSITIF DE DÉTECTION DE TRACE DE GAZ GAS TRACE DETECTION DEVICE
La présente invention concerne un dispositif de détection de traces de gaz. Elle s'applique, en particulier, à la détection de trace de gaz représentatifs d'une pollution de l'air ou de danger sur un site. The present invention relates to a device for detecting traces of gas. It applies, in particular, to the detection of traces of gases representative of air pollution or danger on a site.
On connaît des dispositifs complexes de détection de traces de gaz par détection d'absorption d'énergie lumineuse à une longueur d'onde caractéristique de ce gaz. Ces systèmes sont lourds et donc limités à une utilisation statique, en laboratoire. Des échantillons d'air sont prélevés sur site puis utilisés en laboratoire. Complex gas trace detection devices are known by detecting light energy absorption at a characteristic wavelength of this gas. These systems are heavy and therefore limited to static use in the laboratory. Air samples are collected on site and used in the laboratory.
Ils ne permettent donc pas une analyse rapide, voire en temps réel, de la qualité de l'air avec des centaines, voire des milliers de prélèvements et, encore moins, par analyse continue de l'air pendant le déplacement du dispositif. They do not allow a rapid analysis, even in real time, air quality with hundreds, even thousands of samples and even less, by continuous analysis of air during movement of the device.
La présente invention vise à remédier à ces inconvénients. The present invention aims to remedy these disadvantages.
A cet effet, la présente invention vise un dispositif de détection de traces de gaz qui comporte, dans un caisson fermé : For this purpose, the present invention aims a gas trace detection device which comprises, in a closed box:
- une cellule d'analyse munie de moyens d'entrée et de sortie d'échantillons d'air, an analysis cell provided with input and output means for air samples,
- une source d'émission laser qui émet un rayon laser à destination de ladite cellule d'analyse, a laser emission source which emits a laser beam to said analysis cell,
- un capteur photosensible principal positionné pour recevoir le rayon laser sortant de ladite cellule d'analyse et adapté à émettre un signal représentatif de l'intensité lumineuse reçue par ledit capteur et a main photosensitive sensor positioned to receive the laser beam coming out of said analysis cell and adapted to emit a signal representative of the light intensity received by said sensor and
- un moyen de maintien en température adapté à maintenir à une température prédéterminée constante, conjointement : a means of maintaining a temperature adapted to maintain at a constant predetermined temperature, jointly:
- la source d'émission laser, - the source of laser emission,
- l'air entrant dans la cellule d'analyse, - the air entering the analysis cell,
- un banc optique supportant la cellule et la source d'émission laser et an optical bench supporting the cell and the laser emission source and
- le contenu du caisson fermé. - the contents of the closed box.
Grâce à ces dispositions, tous les éléments se trouvant dans le caisson ainsi que l'air ambiant sont maintenus à une température constante. La précision de la détection est ainsi améliorée. En particulier, grâce à la thermalisation de la source d'émission laser, il n'est pas nécessaire d'asservir le laser en fréquence d'émission. With these provisions, all the elements in the box and the ambient air are maintained at a constant temperature. The accuracy of the detection is thus improved. In particular, thanks to the thermalization of the laser emission source, it is not necessary to control the laser transmission frequency.
De plus, le dispositif est autonome et n'a pas besoin de re-calibration. Enfin, le dispositif peut être miniaturisé pour tenir dans un véhicule, par exemple une camionnette afin de prélever, en continu, de l'air ambiant et réaliser une cartographie précise des traces de gaz détectées. In addition, the device is autonomous and does not need re-calibration. Finally, the device can be miniaturized to fit in a vehicle, for example a van to continuously take ambient air and accurately map the traces of gas detected.
Selon des caractéristiques particulières, la source d'émission laser est de type laser à cascade quantique (« QCL » ou « Quantum Cascade Laser »). According to particular features, the laser emission source is of the quantum cascade laser type ("QCL" or "Quantum Cascade Laser").
La technologie laser à cascade quantique (« QCL ») offre une gamme de lasers dans le moyen infrarouge qui rend accessible les longueurs d'onde caractéristiques d'un très vaste ensemble de molécules complexes. Quantum cascade laser technology (QCL) offers a range of lasers in the mid-infrared that makes wavelengths characteristic of a very large set of complex molecules accessible.
Selon des caractéristiques particulières, le dispositif objet de la présente invention comporte, en outre, un laser visible et un support de miroir adapté à réfléchir le faisceau laser issu du laser visible sur le chemin optique de la source d'émission laser. According to particular features, the device of the present invention further comprises a visible laser and a mirror support adapted to reflect the laser beam from the visible laser on the optical path of the laser emission source.
Ce laser visible permet, grâce à un miroir amovible positionné sur le chemin optique de la source d'émission laser, de visualiser le chemin optique et de positionner correctement les miroirs et la cellule d'analyse. This visible laser makes it possible, thanks to a removable mirror positioned on the optical path of the laser emission source, to visualize the optical path and to correctly position the mirrors and the analysis cell.
Selon des caractéristiques particulières, le caisson est un caisson étanche doublé de mousse thermique à l'intérieur. According to particular characteristics, the box is a waterproof box lined with thermal foam inside.
Selon des caractéristiques particulières, le dispositif objet de l'invention comporte une bouteille d'air sec sous pression dont la sortie est reliée à l'intérieur du caisson. Cette bouteille d'air sec permet de purger le gaz, et donc l'humidité, dans le caisson. According to particular features, the device that is the subject of the invention comprises a bottle of pressurized dry air whose outlet is connected to the inside of the box. This bottle of dry air makes it possible to purge the gas, and therefore the humidity, in the box.
Selon des caractéristiques particulières, le dispositif objet de l'invention comporte, à l'intérieur du caisson, au moins un ventilateur supporté à travers le banc optique. According to particular features, the device of the invention comprises, inside the box, at least one fan supported through the optical bench.
Grâce à ces dispositions, la transmission des vibrations du ventilateur aux éléments optique est réduite. En effet, l'homme du métier est dissuadé de prévoir un ventilateur à proximité d'éléments d'un banc optique, tant le premier est source de vibrations et le second doit être protégé des vibrations. En supportant le ventilateur, par des ouvertures réalisées dans le banc optique, les vibrations du ventilateur sont transmises à un support sans passer par le banc optique. Selon des caractéristiques particulières, le moyen de maintien en température comporte un échangeur de chaleur mettant en température, par conduction thermique, ledit banc optique. Thanks to these arrangements, the transmission of the vibrations of the fan to the optical elements is reduced. Indeed, the skilled person is discouraged to provide a fan near elements of an optical bench, both the first is a source of vibration and the second must be protected from vibration. By supporting the fan, through openings in the optical bench, the vibrations of the fan are transmitted to a support without passing through the optical bench. According to particular characteristics, the temperature-maintaining means comprises a heat exchanger putting into temperature, by thermal conduction, said optical bench.
Selon des caractéristiques particulières, le dispositif objet de l'invention comporte un moyen de pompage de l'air présent dans la cellule d'analyse. Ainsi, le gaz échantillon est pompé en sortie pour maintenir la cellule d'analyse sous faible pression. According to particular features, the device which is the subject of the invention comprises means for pumping air present in the analysis cell. Thus, the sample gas is pumped out to maintain the analysis cell under low pressure.
Selon des caractéristiques particulières, au moins une électrovanne, placée en amont de la cellule d'analyse, est asservie à une mesure de pression en entrée de la cellule d'analyse l'ouverture de l'électrovanne provoquant une variation de la pression à l'intérieur de la cellule d'analyse. According to particular features, at least one solenoid valve, placed upstream of the analysis cell, is slaved to a pressure measurement at the input of the analysis cell, the opening of the solenoid valve causing a variation of the pressure at the inlet of the solenoid valve. inside the analysis cell.
Selon des caractéristiques particulières, une partie de la lumière émise par la source d'émission laser réfléchie sur la surface transparente en entrée de la cellule d'analyse est reçue, par l'intermédiaire d'un barreau de Germanium, par un capteur photosensible secondaire. Le signal en sortie de ce capteur photosensible secondaire sert de référence d'émission de la source d'émission laser. According to particular features, part of the light emitted by the laser emission source reflected on the transparent surface at the input of the analysis cell is received, via a germanium bar, by a secondary photosensitive sensor . The output signal of this secondary photosensitive sensor serves as the transmission reference of the laser emission source.
Cette boucle de contre-réaction permet d'éviter un asservissement du laser. D'autres avantages, buts et caractéristiques particulières de la présente invention ressortiront de la description qui va suivre faite, dans un but explicatif et nullement limitatif en regard des dessins annexés, dans lesquels : This feedback loop makes it possible to avoid servocontrolling the laser. Other advantages, aims and particular features of the present invention will emerge from the description which follows, for an explanatory and non-limiting purpose with reference to the accompanying drawings, in which:
- la figure 1 représente, schématiquement et en vue de dessus, un mode de réalisation particulier du dispositif objet de la présente invention, FIG. 1 represents, schematically and in plan view, a particular embodiment of the device that is the subject of the present invention,
- la figure 2 représente, schématiquement et en vue de dessus, le dispositif de la figure 1 après retrait d'un échangeur de chaleur, FIG. 2 schematically and in plan view, the device of FIG. 1 after removal of a heat exchanger,
- la figure 3 représente, schématiquement et de côté, le dispositif illustré en figures 1 et 2 et FIG. 3 is a diagrammatic side view of the device illustrated in FIGS. 1 and 2 and
- la figure 4 illustre, sous forme de logigramme, des étapes du procédé de mise en œuvre du dispositif illustré en figures 1 à 3. FIG. 4 illustrates, in the form of a logic diagram, steps of the method for implementing the device illustrated in FIGS. 1 to 3.
On note que les figures ne sont pas à l'échelle. It is noted that the figures are not to scale.
On observe, en regard des figures 1 à 3, que, dans un mode de réalisation particulier, le dispositif 102 objet de l'invention comporte trois parties principales : With reference to FIGS. 1 to 3, it can be seen that, in a particular embodiment, the device 102 which is the subject of the invention comprises three main parts:
- une partie de traitement de l'échantillon d'air, a part of treatment of the air sample,
- une partie thermique et - a thermal part and
- une partie optique. La partie de traitement de l'échantillon d'air comporte : an optical part. The treatment portion of the air sample comprises:
- une cellule d'analyse 1 12, an analysis cell 1 12,
- des tubulures de passage d'air d'échantillon 122, sample air passages 122,
- un filtre 134, a filter 134,
- une électrovanne 136, a solenoid valve 136,
- un tuyau d'air d'échantillon 138, a sample air pipe 138,
- un capteur de pression d'air 140 et an air pressure sensor 140 and
- un tuyau de sortie d'air d'échantillon 142. - a sample air outlet pipe 142.
Une pompe (non représentée) pompe l'air d'échantillon en sortie du tuyau 142. La cellule d'analyse 1 1 2 est de type aérodyne à miroirs toroïdaux. Moyennant l'injection d'un rayon laser sur un axe d'entrée prédéterminée, ce rayon parcourt exactement 76 mètres avant de ressortir de la cellule d'analyse. Les tubulures de passage d'air d'échantillon 122 font parcourir à l'échantillon d'air, quatre fois la longueur d'un échangeur de chaleur 1 20. Le filtre 1 34 est de type connu. L'électrovanne 136 est asservie à la pression mesurée par le capteur de pression d'air entrant 140. La pression à l'intérieur de la cellule est ainsi maintenue à 40 mbar +/- 4 10"3 mbar. A pump (not shown) pumps the sample air at the outlet of the pipe 142. The analysis cell 1 1 2 is of the aerodyne type with toroidal mirrors. By injecting a laser beam on a predetermined input axis, this ray travels exactly 76 meters before emerging from the analysis cell. The sample air passage tubes 122 make the air sample travel four times the length of a heat exchanger 120. The filter 34 is of known type. The solenoid valve 136 is slaved to the pressure measured by the incoming air pressure sensor 140. The pressure inside the cell is thus maintained at 40 mbar +/- 4 10 -3 mbar.
La partie thermique comporte : The thermal part comprises:
- un caisson 104, a box 104,
- l'échangeur de chaleur 1 20 (en figures 1 et 3 uniquement), the heat exchanger 1 (in FIGS. 1 and 3 only),
- des tuyaux de passage d'eau de thermalisation 124, - Thermalization water passage pipes 124,
- une entrée d'eau de thermalisation 126, an inlet of thermalization water 126,
- une sortie d'eau de thermalisation 1 28, an outlet for thermalization water 1 28,
- un radiateur 1 30, - a radiator 1 30,
- deux ventilateurs 132, two fans 132,
- deux capteurs de température de l'air dans le caisson, 144 et 146, two air temperature sensors in the casing, 144 and 146,
- deux capteurs de température d'entrée et de sortie d'air d'échantillon, 148 et 150 et - two sample air inlet and outlet temperature sensors, 148 and 150 and
- un échangeur de chaleur 166. a heat exchanger 166.
Le caisson 104 est étanche. Il est, préférentiellement peint en blanc, pour limiter les rayonnements et doublé, à l'intérieur, d'une mousse thermique. Les échangeurs de chaleur 120 et 166 ont des fonctions différentes. Reliés à la même source d'eau de thermalisation, le premier thermalise, par convection, l'air constituant l'échantillon et le second thermalise, par conduction, le banc optique 1 18. On note que les tuyaux d'amenée et de sortie d'eau, notamment ceux de l'échangeur 166, ne sont pas représentés en figure 3. The box 104 is waterproof. It is, preferably painted white, to limit radiation and doubled, inside, a thermal foam. The heat exchangers 120 and 166 have different functions. Connected to the same source of thermalization water, the first thermalizes, by convection, the air constituting the sample and the second thermalizes, by conduction, the optical bench 1 18. It is noted that the inlet and outlet pipes, in particular those of the exchanger 166, are not shown in FIG.
Le radiateur 1 30 et les deux ventilateurs 132 qui lui sont associés thermalisent l'air ambiant dans le caisson 104. On observe que la source principale d'émission laser 1 06 est, elle aussi, thermalisée par le circuit de thermalisation à eau, par l'intermédiaire de tuyaux 124. The radiator 1 30 and the two fans 132 associated with it heat the ambient air in the box 104. It is observed that the main source of laser emission 1 06 is also thermalized by the water thermalization circuit, by through pipes 124.
La température de l'eau de thermalisation est asservie aux signaux sortant des capteurs de température de l'air dans le caisson, 144 et 146 et des capteurs de température d'entrée et de sortie d'air d'échantillon, 148 et 150. L'air de l'échantillon ainsi que l'air ambiant dans le caisson 104 sont ainsi maintenus à une température de 25 °C + /- 15 103 ° C. The temperature of the thermalization water is controlled by the signals output from the air temperature sensors in the casing 144 and 146 and the sample air inlet and outlet temperature sensors 148 and 150. the air in the sample and the ambient air in the chamber 104 are thus maintained at a temperature of 25 ° C + / - 15 October 3 C.
Grâce à la thermalisation de la source d'émission laser 106, il n'est pas nécessaire d'asservir le laser en fréquence d'émission. With the thermalization of the laser emission source 106, it is not necessary to slave the laser transmission frequency.
La partie optique comporte : The optical part comprises:
une source principale d'émission laser 1 06, a main source of laser emission 1 06,
un premier miroir plan 1 08, a first plane mirror 1 08,
un capteur photosensible principal 156 (figure a main photosensor sensor 156 (FIG.
un capteur photosensible secondaire 1 10, a secondary photosensitive sensor 1 10,
une source secondaire d'émission laser 1 14, a secondary source of laser emission 1 14,
un support 1 16 pour un miroir plan amovible, a support 1 16 for a removable flat mirror,
- un banc optique 1 18 et an optical bench 1 18 and
- deux miroirs plans 1 52 et 154 (figure 2). two flat mirrors 1 52 and 154 (FIG. 2).
La source principale d'émission laser 1 06 est de type laser à cascade quantique (« QCL » ou « Quantum Cascade Laser »). La technologie laser à cascade quantique (« QCL ») offre une gamme de lasers dans le moyen infrarouge qui rend accessible les longueurs d'onde caractéristiques d'un très vaste ensemble de molécules complexes. Comme illustré en figure 2, quatre chemins optiques sont suivis par différents rayons lumineux, en dehors de la cellule d'analyse 1 12. Un chemin optique principal d'entrée de rayons laser dans la cellule 1 12 comporte la source laser 106, munie d'une optique, le miroir 1 08 et le miroir 154. Lorsqu'un miroir plan amovible (non représenté) est positionné sur le support 1 16, un rayon laser visible émis par la source secondaire 1 14 se reflète sur ce miroir et suit, ensuite, le même chemin optique que le rayon laser issu de la source principale 1 06. On peut ainsi visualiser, grâce au rayon visible, ce chemin optique principal et positionner les miroirs 108 et 154 avec précision. En sortie de la cellule d'analyse 1 12, le rayon laser se reflète sur le miroir 152 et atteint le capteur photosensible principal 1 56. Celui-ci fournit un signal représentatif de l'absorption d'énergie lumineuse dans l'échantillon d'air présent dans la cellule d'analyse 1 1 2. The main source of laser emission 106 is of the quantum cascade laser type ("QCL" or "Quantum Cascade Laser"). Quantum cascade laser technology (QCL) offers a range of lasers in the mid-infrared that makes wavelengths characteristic of a very large set of complex molecules accessible. As illustrated in FIG. 2, four optical paths are followed by different light rays, outside the analysis cell 1, 12. A main optical path of entry of laser beams into the cell 1 12 comprises the laser source 106, provided with an optic, the mirror 108 and the mirror 154. When a removable planar mirror (not shown) is positioned on the support 1 16, a visible laser beam emitted by the secondary source 1 14 is reflected on this mirror and follows, then, the same optical path as the laser beam from the main source 1 06. It is thus possible to visualize, thanks to the visible ray, this main optical path and to position the mirrors 108 and 154 accurately. At the output of the analysis cell 1 12, the laser beam is reflected on the mirror 152 and reaches the main photosensitive sensor 1 56. This provides a signal representative of the light energy absorption in the sample. air present in the analysis cell 1 1 2.
Enfin, une partie du rayon laser se reflète sur la face d'entrée de la cellule d'analyse 1 12 et atteint, par l'intermédiaire d'un barreau de Germanium, le capteur photosensible secondaire 1 10. Le signal électrique émis par le capteur photosensible 1 10 sert de référence pour la calibration du signal sortant du capteur photosensible 156. Cette boucle de contre-réaction permet d'éviter un asservissement du laser. Finally, a part of the laser beam is reflected on the input face of the analysis cell 1 12 and reaches, via a germanium bar, the secondary photosensitive sensor 1 10. The electrical signal emitted by the The photosensitive sensor 1 10 serves as a reference for the calibration of the output signal of the photosensitive sensor 156. This feedback loop makes it possible to avoid servocontrolling the laser.
Ensemble, les signaux issus des capteurs photosensibles 1 10 et 156 permettent de déterminer avec une grande sensibilité et une grande précision, la proportion de traces d'un gaz absorbant la longueur d'onde émise par la source 1 06, dans l'échantillon. A cet effet, on met en œuvre la loi de Bert-Lambert. Together, the signals from the photosensitive sensors 10 and 156 make it possible to determine with great sensitivity and precision the proportion of traces of a gas absorbing the wavelength emitted by the source 106 in the sample. For this purpose, we implement the law of Bert-Lambert.
De plus, le dispositif 102 comporte : In addition, the device 102 comprises:
- des silent-blocs 1 60 de supports de banc optique, silent-blocks 1 60 of optical bench supports,
- des pieds de support de radiateur 162 et radiator support legs 162 and
- des silent-blocs 1 64 de pieds de support de radiateur. - silent-blocks 1 64 of radiator support feet.
Préférentiellement, le dispositif 102 comporte, à l'intérieur du caisson 104, au moins un ventilateur 132 supporté à travers le banc optique 1 18. En supportant chaque ventilateur 1 32, par des ouvertures réalisées dans le banc optique 1 18, les vibrations de ce ventilateur 132 sont transmises à un support sans passer par le banc optique 1 18. Par exemple, chaque ventilateur 132 est supporté par le support de l'échangeur 130. La séparation du support de l'échangeur 130, qui porte les ventilateurs 1 32 et du support du banc optique 1 18, ainsi que la présence de silent- blocs entre eux permet de réduire les vibrations du banc optique 1 18. Preferably, the device 102 comprises, inside the box 104, at least one fan 132 supported through the optical bench 1 18. Supporting each fan 1 32, through openings in the optical bench 1 18, the vibrations of this fan 132 is transmitted to a support without passing through the optical bench 1 18. For example, each fan 132 is supported by the support of the exchanger 130. The separation of the support of the exchanger 130, which carries the fans 1 32 and the support of the optical bench 1 18, as well as the presence of silent blocks between them makes it possible to reduce the vibrations of the optical bench 1 18.
Une bouteille d'air sec sous pression (non représentée) permet de purger le gaz (et donc l'humidité) dans le caisson 1 04 et dans la cellule d'analyse 1 12. A bottle of pressurized dry air (not shown) makes it possible to purge the gas (and thus the moisture) in the well 1 04 and in the analysis cell 1 12.
Les inventeurs ont obtenus les caractéristiques suivantes pour un dispositif objet de la présente invention : The inventors obtained the following characteristics for a device that is the subject of the present invention:
- précision < 1 %, - accuracy <1%,
- rapidité : 1 -10 Hz, - speed: 1 -10 Hz,
- stabilité : 2-4 semaines, - stability: 2-4 weeks,
- capacité à effectuer des mesures de « terrain » entre - 5 ° C et 55 °C, et - ability to perform "field" measurements between -5 ° C and 55 ° C, and
- autonomie : pas besoin de re-calibration. Les applications de la présente invention comprennent la détection de : - autonomy: no need for re-calibration. The applications of the present invention include the detection of:
- gaz à effet de serre : N20, CH4, C02 - greenhouse gases: N 2 0, CH 4 , C0 2
- traceurs atmosphériques : isotopes, - atmospheric tracers: isotopes,
- pollution atmosphérique : S02, ... - atmospheric pollution: S0 2 , ...
Comme on l'observe en regard de la figure 4, pour mettre en œuvre le dispositif illustré en figures 1 à 3, on effectue, d'abord, une étape 200 de mise en fonctionnement, c'est-à-dire, notamment de mise sous tension des composants et éléments du dispositif 102. Puis, au cours d'une étape 205, on attend que le dispositif 1 02 atteigne son équilibre thermique, en fonction des signaux représentatif de chaleur sortant des capteurs 144 à 1 50 et de données d'apprentissage. Au cours d'une étape 210, on purge le caisson 104 et la cellule d'analyse 1 12, avec le contenu de la bouteille d'air sec sous pression. As seen with reference to FIG. 4, in order to implement the device illustrated in FIGS. 1 to 3, a first stage 200 of operation is carried out first, that is to say, in particular powering the components and elements of the device 102. Then, during a step 205, it is expected that the device 1 02 reaches its thermal equilibrium, as a function of the representative signals of heat leaving the sensors 144 to 1 50 and data learning. During a step 210, the well 104 and the analysis cell 112 are purged with the contents of the pressurized dry air bottle.
Au cours d'une étape 215, on allume la source d'émission laser 106. Au cours d'une étape 220, on prélève un échantillon d'air. En particulier, le dispositif 102 pouvant être monté sur un véhicule, le prélèvement d'échantillons peut être continu et géolocalisé. Au cours d'une étape 225, on mesure l'intensité lumineuse reçue par le capteur photosensible 156. Au cours d'une étape 230, on mesure l'intensité lumineuse reçue par le capteur photosensible 1 10. Au cours d'une étape 235, on détermine la concentration, dans l'air de l'échantillon, d'une molécule qui absorbe la longueur d'onde émise par la source 106. Puis, on retourne à l'étape 220. During a step 215, the laser emission source 106 is turned on. During a step 220, an air sample is taken. In particular, the device 102 can be mounted on a vehicle, the sampling can be continuous and geolocated. During a step 225, the light intensity received by the photosensitive sensor 156. is measured. During a step 230, the light intensity received by the photosensitive sensor 1 10 is measured. During a step 235 the concentration in the sample air of a molecule which absorbs the wavelength emitted by the source 106 is determined. Then, step 220 is returned.
Claims
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR1156650 | 2011-07-21 | ||
| FR1156650A FR2978247B1 (en) | 2011-07-21 | 2011-07-21 | GAS TRACE DETECTION DEVICE |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2013010984A2 true WO2013010984A2 (en) | 2013-01-24 |
| WO2013010984A3 WO2013010984A3 (en) | 2013-09-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2012/063897 Ceased WO2013010984A2 (en) | 2011-07-21 | 2012-07-16 | Device for detecting trace gases |
Country Status (2)
| Country | Link |
|---|---|
| FR (1) | FR2978247B1 (en) |
| WO (1) | WO2013010984A2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103678730A (en) * | 2013-12-30 | 2014-03-26 | 深圳Tcl新技术有限公司 | Method and device for acquiring photosensitive sensor data |
| CN107391951A (en) * | 2017-08-03 | 2017-11-24 | 江苏卓易信息科技股份有限公司 | A kind of air pollution source tracing method based on the sequence of annular neighborhood gradient |
| CN115753647A (en) * | 2022-11-30 | 2023-03-07 | 达仁智能科技(佛山)有限公司 | A photosensitive sensor performance detection device |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6527398B1 (en) * | 2000-06-08 | 2003-03-04 | Gregory J. Fetzer | Tubular-waveguide gas sample chamber for optical spectrometer, and related methods |
| EP1655596A1 (en) * | 2004-11-09 | 2006-05-10 | Picarro Inc. | Apparatus and method for maintaining uniform and stable temperature for cavity enhanced optical spectroscopy |
| US20060263256A1 (en) * | 2005-05-17 | 2006-11-23 | Nitrex Metal Inc. | Apparatus and method for controlling atmospheres in heat treating of metals |
| US7616316B1 (en) * | 2006-02-27 | 2009-11-10 | Southwest Sciences Incorporated | Gas measurement over extreme dynamic range of concentrations |
| US8154728B2 (en) * | 2008-12-31 | 2012-04-10 | Spectrasensors, Inc. | Analytical equipment enclosure incorporating phase changing materials |
| JP2010230370A (en) * | 2009-03-26 | 2010-10-14 | Shimadzu Corp | Infrared spectrophotometer and attached devices |
-
2011
- 2011-07-21 FR FR1156650A patent/FR2978247B1/en active Active
-
2012
- 2012-07-16 WO PCT/EP2012/063897 patent/WO2013010984A2/en not_active Ceased
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| Title |
|---|
| None |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103678730A (en) * | 2013-12-30 | 2014-03-26 | 深圳Tcl新技术有限公司 | Method and device for acquiring photosensitive sensor data |
| CN107391951A (en) * | 2017-08-03 | 2017-11-24 | 江苏卓易信息科技股份有限公司 | A kind of air pollution source tracing method based on the sequence of annular neighborhood gradient |
| CN107391951B (en) * | 2017-08-03 | 2020-10-23 | 江苏卓易信息科技股份有限公司 | Air pollution tracing method based on annular neighborhood gradient sorting |
| CN115753647A (en) * | 2022-11-30 | 2023-03-07 | 达仁智能科技(佛山)有限公司 | A photosensitive sensor performance detection device |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2978247B1 (en) | 2014-09-05 |
| FR2978247A1 (en) | 2013-01-25 |
| WO2013010984A3 (en) | 2013-09-19 |
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