WO1999060384A1 - Dispositif pour determiner des concentrations de gaz - Google Patents

Dispositif pour determiner des concentrations de gaz Download PDF

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Publication number
WO1999060384A1
WO1999060384A1 PCT/EP1999/003299 EP9903299W WO9960384A1 WO 1999060384 A1 WO1999060384 A1 WO 1999060384A1 EP 9903299 W EP9903299 W EP 9903299W WO 9960384 A1 WO9960384 A1 WO 9960384A1
Authority
WO
WIPO (PCT)
Prior art keywords
measuring
measuring station
telephone
light
station
Prior art date
Application number
PCT/EP1999/003299
Other languages
German (de)
English (en)
Inventor
Gerhard Müller
Original Assignee
Laser- Und Medizin-Technologie Ggmbh, Berlin
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Laser- Und Medizin-Technologie Ggmbh, Berlin filed Critical Laser- Und Medizin-Technologie Ggmbh, Berlin
Publication of WO1999060384A1 publication Critical patent/WO1999060384A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/0264—Electrical interface; User interface
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28—Investigating the spectrum
    • G01J3/44—Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N35/00584—Control arrangements for automatic analysers
    • G01N35/00722—Communications; Identification
    • G01N35/00871—Communications between instruments or with remote terminals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/02—Devices for withdrawing samples
    • G01N1/22—Devices for withdrawing samples in the gaseous state
    • G01N1/2273—Atmospheric sampling
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N35/00584—Control arrangements for automatic analysers
    • G01N35/00722—Communications; Identification
    • G01N35/00871—Communications between instruments or with remote terminals
    • G01N2035/00881—Communications between instruments or with remote terminals network configurations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0006—Calibrating gas analysers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0062—General constructional details of gas analysers, e.g. portable test equipment concerning the measuring method or the display, e.g. intermittent measurement or digital display

Definitions

  • the invention relates to a device for regional detection of the relative concentration of at least one gaseous substance in an ambient gas, in particular in air, with at least one detection center and at least one measuring station which can be remotely controlled and / or queried.
  • Such a device is used, for example, for the detection of pollutant concentrations in the air in metropolitan areas, in the vicinity of industrial plants or landfills.
  • a number of measuring stations distributed over an area are connected to an acquisition center via radio, in particular via trunked radio.
  • the measuring stations are equipped with sensors for the 'respectively to be monitored relative concentrations of pollutants.
  • different measuring methods are used to determine the concentration.
  • the concentration of sulfur dioxide is determined from the analysis of UV fluorescence, while the method of non-dispersive infrared absorption is used for carbon monoxide, a chemiluminescence method is used for nitrogen oxides and a UV absorption method is used for ozone.
  • parallel electrical (conductivity determination) and radiological measurement methods (beta absorption) are used.
  • the large number of methods used in a measuring station initially requires a great technical and financial outlay, since numerous different measuring devices and corresponding equipment for supplying the measuring apparatus with the electrical power required for operation must be provided.
  • the measuring stations are usually housed in air-conditioned containers with dimensions of approximately 2 * 2 * 2 m.
  • the maintenance of the various measuring devices of a measuring station, for example reagents have to be replaced, as well as the often complicated evaluation of the measurement results requires a great deal of work by qualified technical personnel. Therefore, maintaining a dense network of measuring stations is currently uneconomical. In addition, high demands must be placed on the locations of the measuring containers (existing power supply, sufficient space).
  • Raman spectroscopy can be used to determine the relative concentration of a gas in an ambient gas.
  • a corresponding device is described for example in the document DE 27 23 939 C2.
  • this is a system intended for clinical or laboratory use, in which the gases to be measured are examined under defined, constant boundary conditions.
  • the widespread use of such a device in environmental analysis is desirable, but has so far not been possible due to the high price of adequate, powerful and stable light sources and the relatively complex optical equipment to achieve an appropriate measurement sensitivity. bar.
  • the light source is at least one green or blue light-emitting diode laser or optically pumped microchip laser
  • the light detector or a second light detector is designed in such a way that it also converts the light intensity raman scattered in the measuring cell into a proportional
  • second electrical measurement signal converts that a temperature sensor for generating a third electrical measurement signal proportional to the temperature of the ambient gas and a pressure sensor for generating a fourth electrical measurement signal proportional to the pressure of the ambient gas are provided in the measuring station, and that the four measurement signals for evaluation by telephone to the Registration center are communicable.
  • the concentration of numerous pollutants in the air can be measured simultaneously.
  • gases and vapors of interest for environmental analysis nitrogen (N2), oxygen (02), carbon dioxide (C02), ozone (03), sulfur dioxide (S02), carbon monoxide (CO), benzene (C6H6), hydrogen sulfide (H2S) , Ammonia (NH3), hydrogen chloride (HCl), toluene and xylene.
  • the Raman scattering intensity of the pollutants to be investigated that of the nitrogen contained in the sample is also measured according to the invention.
  • the relative concentrations of the pollutants can be determined from this by forming a ratio.
  • the air pressure and temperature values for calibration and drift compensation, which are simultaneously determined according to the invention, are included in the evaluation.
  • the use according to the invention of a green or blue diode laser or optically pumped microchip laser enables the measurement method to be used inexpensively.
  • the Raman scattering cross-section of the gases of interest is particularly large when interacting with green and, in particular, blue light, without the disruptive luminescence of the gases significantly overlaying the signal.
  • the lasers mentioned can therefore be operated with powers in the order of magnitude of 100 mW. Such lasers with stable performance in this area can now be produced inexpensively.
  • the measured values can be transmitted to the data acquisition center in real time by telephone and are immediately available for evaluation and for making environmental forecasts.
  • a multipass cell into which the gas to be examined is introduced is preferably used to generate a high scattering intensity. In this way, a laser photon is passed through the gas sample several times, which increases the likelihood of it being scattered.
  • a preferred embodiment of the invention uses the connections present in a telephone booth for data transmission and for supplying the measuring station with electrical power.
  • This variant has the great advantage that no additional infrastructure has to be provided for the erection of the measuring station.
  • telephone booths in cities are numerous and set up at relatively even intervals, so that a close-meshed measuring network that was previously not considered possible can be set up inexpensively.
  • the measured values determined can be queried by anyone or by telephone or via the Internet. This is a great help, especially for ozone-sensitive people, to help them assess their performance.
  • Another embodiment of the invention has mobile measuring stations which are arranged on road, rail or aircraft and which transmit the measured values to the detection center via mobile radio. In this way, pollutant concentrations can also be detected over a large area in a simple manner.
  • the device according to the invention is particularly suitable for detecting the spread of pollutant clouds and thus enables an early prognosis for warning the population of regions at risk from the pollutant cloud.
  • FIG. 1 shows a schematic representation of the device according to the invention
  • FIG. 2 shows a partially sectioned side view of a multipass cell according to the invention
  • Figure 3 is a partially sectioned front view of the multipass cell of Figure 1 and
  • Figure 4 is a circuit diagram for the gas flow in the measuring station.
  • Figure 1 shows an embodiment of the invention in a block diagram of a device 2 for regional detection of gaseous environmental pollutants.
  • a measuring station 4 and an acquisition center 6 are shown.
  • the heart of the measuring station 4 is a Raman multi-gas sensor 8, which is described in more detail below with reference to the following figures.
  • the measuring station 4 is arranged on the roof of a telephone booth 10 and is connected to the corresponding supply devices 12 provided for the operation of the telephone booth 10 in order to supply electrical power.
  • a measurement controller 14 controls the operation of the Raman multi-gas sensor 8 and uses a memory controller 16 to store the measurement data generated by it in a memory 18.
  • a connection controller 20 With the aid of a connection controller 20, a telephone connection to the acquisition center 6 is established via a modem 22 and a network termination unit 24 provided in the telephone booth 10 in order to transmit the data stored in the memory to a central computer 26 installed there.
  • the detection center also has a network termination unit 25 which is connected to a modem 27.
  • the transmitted data are stored and evaluated in the central computer 26.
  • the respective time of transmission can be predetermined from the central computer 26 by remote-controlled programming of the connection controller 22. Basically, with the device shown, the current measured values can be queried from the central computer at any time.
  • the latter can in turn access and output the stored measured values and the evaluated data by remote inquiry by telephone or via the Internet.
  • the controls 14 to 16, the memory 18 and the modem 22 are accommodated in a compact computer unit 28 with processor and working memory (not shown) and can be hard-wired or stored in the form of executable program files in the memory 18.
  • the second variant has the advantage that updated control programs can be installed remotely on all measuring stations from the central computer.
  • the measuring station described is to be operated independently of a telephone booth, a radio telephone and a corresponding modem must be provided instead of being connected to the network termination unit of the telephone booth.
  • FIG. 2 shows, in a partially sectioned side view, the core of the Raman multi-gas sensor 8, a multipass cell 30. It forms an essentially hollow cylindrical housing 32 of approximately 10 cm in diameter and approximately 40 cm in length, which rests on a base plate 38 with two supports 34 and 36. At one longitudinal end, an adjustable laser holder 40 is attached, on which a laser 42 is arranged. In the middle of the diameter and the longitudinal extent of the housing 32 and at the same time approximately in the focal point of a multipass arrangement, which is formed by two concave mirrors 44 and 46 arranged near the longitudinal ends, there is a transparent measuring cell (not shown here) with a gas sample. For the measurement via the gas system of the measuring station described below with reference to FIG. 4, the measuring cell is either continuously flushed through by the medium to be examined or previously filled with a defined amount of gas.
  • a green or blue diode laser is used for the measurements.
  • diode-pumped solid-state lasers with internal frequency doubling for example an Nd: YAG laser (532 nm)
  • Nd: YAG laser 532 nm
  • the wavelength of the emitted light is essential. Raman scattering cross sections of the gases to be detected are particularly high in the green and blue spectral range. Furthermore, the emitted light output should be around 100mW.
  • the types mentioned are particularly preferred because of their compact design and high efficiency, which are essential for the invention. Since the development of semiconductor lasers in the green and blue spectral range is currently making great progress, it can be assumed that even smaller laser modules will be available in the future with a further reduced power consumption.
  • the laser 42 radiates into the housing 32 through a not shown Inlet optics 48, which is provided with a shutter mechanism for recording the dark count rate of detectors described below.
  • the laser beam symbolized by a dotted line 50, runs in the longitudinal direction of the housing 32 in a vertical central plane and intersects the axis in the middle of the longitudinal extent of the housing at an acute angle.
  • the non-scattered light strikes the rear radiation concave mirror 46 and is then reflected back and forth by the multipass arrangement between the mirrors 44 and 46.
  • the sample is irradiated with each pass, which is known to significantly increase the scattered light intensity compared to a simple arrangement without a multipass.
  • a detector device 52 is installed in the region of a central plane of the housing perpendicular to the axis. It consists of six photomultiplier brackets 54 arranged at the same distance from one another in the circumferential direction. Photomultiplier housings 56 and, in the lower, cut part of the figure, openings 58 provided with detection optics can be seen in FIG. 2 as components of the brackets 54.
  • FIG. 3 shows the arrangement of the photomultiplier brackets 54 in a partially sectioned front view.
  • Lens and filter combinations 60 are visible in the section of the drawing. Since each photomultiplier is provided for the detection of one gas, a specific filter combination is arranged in each holder 54.
  • the filter combinations are each designed as single or multi-band filters so that, depending on the gas, they are only permeable to the wavelengths of one or more characteristic Raman scattering lines.
  • the approximately cylindrical photomultiplier tube (not shown) is inserted through a circular opening 62 and irradiated in operation from the direction perpendicular to the axis (“side-on”). Devices for the high voltage supply of the detectors are not shown in detail.
  • the photomultipliers are operated in the single photon count mode. The intensity of the Raman signal is thus measured as the number of photons registered over a time interval.
  • the photomultiplier is followed by a photon counting chain integrated in the measuring control 14.
  • the single photon count has the advantage that the signal can be integrated over adjustable long periods of time and can thus be measured with very high accuracy if required.
  • the number of photons registered by each photomultiplier is recorded in the memory 18.
  • the dark pulse rate of each photomultiplier is determined at regular intervals and the Corrected measured value accordingly by subtraction. This can take place in the measuring station itself or after the counting rates and the dark pulse rates have been transmitted by the central computer 26 in the detection station 6.
  • the count rate measured for this gas is divided by the count rate measured simultaneously for nitrogen.
  • the evaluation is also based on the simultaneously determined absolute air pressure and the temperature at the measuring station. In accordance with the general state equation for gases, these determine the number of gas particles contained in a reference volume and thus also the scatter rates.
  • the gas system of the Raman multi-gas sensor 8 is explained below with reference to FIG. 4.
  • two alternative inputs 64 and 66 are provided, through which the gas to be examined can flow into the multi-gas sensor 8.
  • the second input 66 is provided for connecting gas bottles for calibration measurements, while the first input is used in regular measuring operation.
  • Particle filters 68 and 70 are connected downstream of both inputs, each of which has a coarse filter with 0.45 micrometers and a fine filter with 0.2 micrometer pores.
  • a two-way valve 72 which can optionally be set electromagnetically by hand or by the measurement controller 14, allows gas to flow from the first input 64 in the actuated state and gas from the second input 66 into the multipass cell 30 in the non-actuated state.
  • a pressure sensor 72 is connected in parallel to the multipass cell, which measures the absolute pressure and generates a corresponding electrical signal, the value of which is written into the memory 18.
  • the multipass cell 30 is followed by a second and a third two-way valve 76 and 78, of which the first (76) in the non-actuated state is permeable to the second (78) and is actuated only for calibration measurements with gases flowing in under excess pressure in order to carry out a relative pressure measurement perform a corresponding sensor 80.
  • the sensor 80 measures the difference between the pressure of the gas in the multipass cell and the environment.
  • Both pressure sensors 74 and 80 are connected on the outlet side to a first outlet 82 through which the gas escapes into the environment.
  • a sensor for measuring the relative air humidity and a sensor for measuring the ambient temperature are not shown. Both continuously provide measurement signals that digitized and stored in memory 18.
  • the third two-way valve 78 leads in the non-actuated state to a second outlet 84 and in the actuated state to the input of a pump 86. This is actuated for the suction of the gas samples through the inputs 64 and 66 (as long as no excess pressure is applied there) and is also on the output side connected to the second outlet 84.
  • the pump can be used to draw in defined amounts of gas as well as for continuous operation.
  • the structure described with reference to the figures can be easily installed in a frame approximately the size of a suitcase and thus forms an easily and inconspicuously installable measuring station.
  • a holographic grating can be used in connection with a CCD line for intensity measurement. The entire spectrum of the scattered light is recorded.
  • a notch filter is preferably arranged between the sample and the CCD line. The size of a measuring station with this equipment is reduced even further.
  • cooling is required, preferably in the form of a Peltier cooler. The disadvantage of this is the greater energy consumption of such a device.
  • An accumulator can of course also be used to power the measuring station, preferably supplemented by a solar system. Operation on an accumulator has the advantage that the measuring station can be used in a mobile manner.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Human Computer Interaction (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
  • Alarm Systems (AREA)

Abstract

L'invention concerne un dispositif pour déterminer la concentration d'une matière gazeuse dans un gaz ambiant contenant de l'azote, notamment dans l'air. Ce dispositif comprend une centrale de détection et une station de mesure qui présente, pour la mesure de la concentration, une source lumineuse, une cellule de mesure et un détecteur de lumière qui convertit en un signal de mesure l'intensité lumineuse émise par la source lumineuse et diffusée avec un effet Raman par la matière gazeuse dans la cellule de mesure. La source lumineuse est une diode laser émettant une lumière verte ou bleue ou un laser à micropuce à pompage optique. Lorsque le détecteur de lumière ou un deuxième détecteur de lumière sont conçus de façon à convertir également en un deuxième signal de mesure l'intensité lumineuse diffusée avec un effet Raman par l'azote contenu dans la cellule de mesure, un détecteur de température et un détecteur de pression sont prévus dans la station de mesure, et les signaux de mesure peuvent être transmis à la centrale de détection par téléphone.
PCT/EP1999/003299 1998-05-16 1999-05-12 Dispositif pour determiner des concentrations de gaz WO1999060384A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1998122161 DE19822161A1 (de) 1998-05-16 1998-05-16 Verfahren und Vorrichtung zur lokalen und regionalen automatisierten Erfassung von Schadstoff Emissions- und Imissionsprofilen
DE19822161.4 1998-05-16

Publications (1)

Publication Number Publication Date
WO1999060384A1 true WO1999060384A1 (fr) 1999-11-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1999/003299 WO1999060384A1 (fr) 1998-05-16 1999-05-12 Dispositif pour determiner des concentrations de gaz

Country Status (2)

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DE (1) DE19822161A1 (fr)
WO (1) WO1999060384A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10429367B2 (en) 2014-05-07 2019-10-01 Qatar University Multi-parametric environmental diagnostics and monitoring sensor node
DE102014202595B4 (de) 2014-02-13 2023-06-07 Robert Bosch Gmbh Verfahren und Vorrichtung zur Sauerstoffbestimmung in einem abgeschlossenen Behälter

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2360095A (en) * 2000-03-10 2001-09-12 Marconi Applied Techn Ltd Chemical sensor array system
US7148484B2 (en) * 2003-01-24 2006-12-12 The Regents Of The University Of California Cellular telephone-based radiation sensor and wide-area detection network
GB2404021B (en) * 2003-07-17 2006-02-22 Ecameter Ltd Emissions meter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2723939A1 (de) * 1977-05-24 1978-12-07 Albrecht Hans Joerg Vorrichtung zur atemgasanalyse
EP0242926A1 (fr) * 1986-04-19 1987-10-28 N.V. Nederlandse Gasunie Méthode pour déterminer une propriété physique d'un milieu
EP0600711A2 (fr) * 1992-12-03 1994-06-08 Hewlett-Packard Company Procédé d'étalonnage d'un spectromètre pour substances gazeuses
WO1994024545A1 (fr) * 1993-04-15 1994-10-27 Board Of Regents, The University Of Texas System Spectrometre raman
US5553006A (en) * 1994-06-09 1996-09-03 Chelsea Group Ltd. Method and apparatus for building environmental compliance

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2723939A1 (de) * 1977-05-24 1978-12-07 Albrecht Hans Joerg Vorrichtung zur atemgasanalyse
EP0242926A1 (fr) * 1986-04-19 1987-10-28 N.V. Nederlandse Gasunie Méthode pour déterminer une propriété physique d'un milieu
EP0600711A2 (fr) * 1992-12-03 1994-06-08 Hewlett-Packard Company Procédé d'étalonnage d'un spectromètre pour substances gazeuses
WO1994024545A1 (fr) * 1993-04-15 1994-10-27 Board Of Regents, The University Of Texas System Spectrometre raman
US5553006A (en) * 1994-06-09 1996-09-03 Chelsea Group Ltd. Method and apparatus for building environmental compliance

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014202595B4 (de) 2014-02-13 2023-06-07 Robert Bosch Gmbh Verfahren und Vorrichtung zur Sauerstoffbestimmung in einem abgeschlossenen Behälter
US10429367B2 (en) 2014-05-07 2019-10-01 Qatar University Multi-parametric environmental diagnostics and monitoring sensor node

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Publication number Publication date
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