JP2020067424A - Gas analysis device - Google Patents

Abstract

To provide a gas analysis device capable of precisely measuring density and a temperature of a gas to be analyzed even under an environment in which a variation in a temperature, density, and a pressure of the gas to be analyzed changes every moment.SOLUTION: A gas analysis device 1A comprises a control part 20A. The control part 20A calculates a temperature value and a density value of a gas to be analyzed based on a ratio of 2f peak values and a pressure value P detected for each of two laser light sources of laser light source pairs for each of the laser light source pairs Pa1 to Pa3. In the control part 20A, a selection part 25A calculates a measurement error for each of the laser light source pairs Pa1 to Pa3 based on noise components of the detected 2f peak values, and selects a laser light source pair having the minimum measurement error as a selection pair. The control part 20A outputs the temperature value and the density value calculated for the selection pair as measurement results.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas analyzer that uses laser light.

  Conventionally, there is known a gas analyzer that measures the concentration of a gas to be analyzed such as hydrocarbon and water contained in exhaust gas from an internal combustion engine. The gas analyzer irradiates the analysis target gas with laser light having a specific wavelength, and detects the concentration of the analysis target gas based on the absorption spectrum of the laser light by the analysis target gas. “RT Ku, ED Hinkley and JO Sample“ Long-path Monitoring of Atmospheric Carbon Monoxide with Tunable Diode Laser System ”, Appl. Opt., 14, 854-861 (1975)” (Non-Patent Document 1) describes a wavelength tunable semiconductor. A gas analysis method using a laser absorption spectroscopy (TDLAS (Tunable Diode Laser Absorption Spectroscopy)) is disclosed.

  By the way, the absorption spectrum of the laser beam by the gas to be analyzed is affected by not only the concentration of the gas to be analyzed but also the temperature and pressure. The degree of influence of temperature and pressure depends on the wavelength of laser light. Therefore, in "Jonathan TC Liu" Near-infrared diode laser absorption diagnostics for temperature and species in engines "High Temperature Gasdynamics Laboratory Department of Mechanical Engineering Stanford University, Stanford, California, October 2004" (Non-patent document 2), high temperature It has been considered to select an optimum laser beam from a plurality of laser beams depending on low temperature, high voltage, and low voltage.

  Japanese Unexamined Patent Application Publication No. 2013-61358 (Patent Document 1) discloses a technique of switching the temperature measurement method according to the concentration of the gas to be analyzed and correcting the absorption spectrum according to the measured temperature. Specifically, when the analysis target gas has a low concentration, the temperature is measured using a temperature sensor such as a thermocouple, and when the analysis target gas has a high concentration, the temperature is calculated from the absorption spectrum. Japanese Patent No. 5983779 (Patent Document 2) discloses a technique of determining a gas concentration using a 2f signal acquired by arithmetic processing.

JP, 2013-61358, A Japanese Patent No. 5983779

R. T. Ku, E. D. Hinkley and J. O. Sample “Long-path Monitoring of Atmospheric Carbon Monoxidewith Tunable Diode Laser System”, Appl. Opt., 14, 854-861 (1975) Jonathan T.C. Liu "Near-infrared diode laser absorption diagnostics for temperature and species in engines" High Temperature Gasdynamics Laboratory Department of Mechanical Engineering Stanford University, Stanford, California, October 2004

  In the exhaust gas of an internal combustion engine, the temperature, concentration and pressure of the gas to be analyzed change every moment. However, Non-Patent Document 2 does not consider a method of selecting a laser in such an environment in which the temperature, the concentration, and the pressure continuously change. Therefore, it is not possible to appropriately select the optimum laser light from the plurality of laser lights according to the environment at the time of measurement, and it is not possible to accurately measure the concentration, temperature and pressure of the gas to be analyzed.

  Further, in Patent Document 1, when the concentration is low, the temperature is measured by a temperature sensor such as a thermocouple. However, the response time of the thermocouple is long, and the concentration, temperature, and pressure of the analysis target gas cannot be accurately measured in an environment in which the temperature, concentration, and pressure of the analysis target gas change momentarily.

  The present disclosure has been made in order to solve the above-described problems, and an object thereof is to analyze an analysis target gas even in an environment in which fluctuations in temperature, concentration, and pressure of the analysis target gas change from moment to moment. An object of the present invention is to provide a gas analyzer capable of accurately measuring the concentration and temperature of.

  A gas analyzer according to an aspect of the present disclosure measures the temperature and concentration of a gas to be analyzed. The gas analyzer detects, for each of the three or more laser light sources that emit laser light of different wavelengths, the absorption information of the laser light emitted from the laser light source from the gas to be analyzed. And a pressure sensor for measuring the pressure value of the gas to be analyzed, a calculation unit, a selection unit, and an output unit. The light absorption information is any of a transmittance, an absorbance, a 2f peak value, a transmittance spectrum, and a value calculated from the transmittance spectrum. The calculation unit detects, for each of two or more laser light source pairs of the three or more laser light sources, the first absorption information detected by the detection unit for one laser light source of the laser light source pair and for the other laser light source. The temperature value and the concentration value of the analysis target gas are calculated based on at least one of the second absorption information detected by the section, the ratio of the first absorption information and the second absorption information, and the pressure value. The selection unit selects a selected pair from two or more laser light source pairs. The output unit outputs the temperature value and the concentration value calculated by the calculation unit for the selected pair as the measurement result. The selection unit, based on the noise component of the light absorption information detected by the detection unit for each of the three or more laser light sources, the temperature value and the concentration value calculated by the calculation unit for each of the two or more laser light source pairs. At least one of the measurement errors is calculated, and the laser light source pair having the smallest calculated measurement error is selected as the selected pair.

  According to the above configuration, of the temperature value and the concentration value calculated for each of the two or more laser light source pairs, the temperature value and the concentration value with a small measurement error are output as the measurement result. As a result, the concentration and temperature of the analysis target gas can be accurately measured even in an environment in which the fluctuations in the temperature, concentration, and pressure of the analysis target gas change from moment to moment.

  A gas analyzer according to another aspect of the present disclosure measures the temperature and concentration of a gas to be analyzed. The gas analyzer detects, for each of the three or more laser light sources that emit laser light of different wavelengths, the absorption information of the laser light emitted from the laser light source from the gas to be analyzed. And a pressure sensor for measuring the pressure value of the gas to be analyzed, a selection unit, a calculation unit, and an output unit. The light absorption information is any of a transmittance, an absorbance, a 2f peak value, a transmittance spectrum, and a value calculated from the transmittance spectrum. The selection unit selects a selected pair from two or more laser light source pairs of the three or more laser light sources. The calculation unit includes at least one of the first absorption information detected by the detection unit for one laser light source and the second absorption information detected by the detection unit for the other laser light source included in the selected pair, and the first absorption information and the second absorption information. The temperature value and the concentration value of the gas to be analyzed are calculated based on the ratio with the absorption information and the pressure value. The output unit outputs the temperature value and the concentration value calculated by the calculation unit as a measurement result. The selection unit selects, from the two or more laser light source pairs, the temperature value and the concentration value under the environment indicated by the temperature value and the concentration value indicated by the measurement result output last time by the output unit and the pressure value measured by the pressure sensor last time. A laser light source pair with a minimum measurement error of at least one of the density values is selected as a selected pair.

  Even in an environment in which the temperature, concentration, and pressure of the gas to be analyzed fluctuate from moment to moment, if the measurement interval is set sufficiently short, the change from the previous measurement result will be small. Therefore, by selecting the laser light source pair with the minimum measurement error under the environment indicated by the temperature value and concentration value shown by the previous measurement result and the pressure value measured last time as the selected pair, Small temperature and concentration values are output as the measurement result. As a result, the concentration and temperature of the analysis target gas can be accurately measured even in an environment in which the fluctuations in the temperature, concentration, and pressure of the analysis target gas change from moment to moment.

  Preferably, the selection unit calculates the measurement error for each of the two or more laser light source pairs based on the noise component of the light absorption information detected by the detection unit.

  According to the above configuration, it is possible to select, as the selected pair, the laser light source pair that has a small measurement error due to the noise component of the absorption information.

  Preferably, the gas analyzer further includes a storage unit that stores a selection map in which the pressure value, the temperature value, and the concentration value are associated with the laser light source pair with the smallest measurement error. The selection unit identifies the laser light source pair corresponding to the temperature value and the concentration value indicated by the measurement result previously output by the output unit and the pressure value previously measured by the pressure sensor from the selection map, and selects the identified laser light source pair. Select as a pair.

  According to the above configuration, by storing the selection map in advance, it is possible to reduce the load required for the selection unit to select the selected pair.

  Preferably, the gas analyzer further includes a temperature sensor that measures the temperature of the analysis target gas and a concentration sensor that measures the concentration of the analysis target gas. The output unit sequentially outputs the measurement results at predetermined measurement intervals. At the time of the first measurement, the output unit outputs the temperature value measured by the temperature sensor, the concentration value measured by the concentration sensor, and the pressure value measured by the pressure sensor as the measurement result. The output unit outputs the temperature value and the concentration value calculated by the calculation unit as the measurement result during the second and subsequent measurements.

  At the start of measurement, the environment of the gas to be analyzed is often stable. Therefore, at the time of the first measurement, the temperature and the concentration of the analysis target gas can be accurately measured even if the temperature sensor and the concentration sensor having a long response time are used.

  Preferably, the output unit sequentially outputs the measurement result at a predetermined measurement interval. The selection unit selects a predetermined laser light source pair as a selected pair during the first measurement.

  At the start of measurement, the environment of the gas to be analyzed is often stable within a predetermined range. In this case, the temperature and the concentration of the first time can be accurately measured by predefining the laser light source pair having a small measurement error under the environment of the predetermined range.

  Preferably, the selection unit specifies from the selection map a plurality of laser light source pairs corresponding to the temperature value and the concentration value indicated by the measurement result output last time by the output unit and the pressure value measured by the pressure sensor last time, and specified. The laser light source pair is selected as the selected pair. The output unit outputs, as a measurement result, a value obtained by interpolation calculation from the temperature value and the concentration value calculated by the calculation unit for each of the plurality of laser light source pairs.

  According to the above configuration, even if the temperature value, the concentration value, and the pressure value measured last time are deviated from the temperature value, the concentration value, and the pressure value of the selection map, the temperature and the concentration of the analysis target gas can be accurately measured. It can be measured.

  A gas analyzer according to another aspect of the present disclosure measures the temperature and concentration of a gas to be analyzed. The gas analyzer detects, for each of the two or more laser light sources that emit laser light of different wavelengths, the absorption spectrum of the laser light emitted from the laser light source due to the analysis target gas. And a detection unit, a selection unit, and an output unit. The calculation unit calculates the temperature value and the concentration value of the analysis target gas for each of the two or more laser light sources, based on the absorption spectrum. The selection unit selects a selection light source from two or more laser light sources. The output unit outputs the temperature value and the concentration value calculated by the calculation unit for the selected light source as the measurement result. The selection unit, based on the noise component of the absorption spectrum detected by the detection unit for each of the two or more laser light sources, selects the temperature value and the concentration value calculated by the calculation unit for each of the two or more laser light sources. At least one measurement error is calculated, and the laser light source with the smallest calculated measurement error is selected as the selected light source.

  According to the above configuration, of the temperature value and the concentration value calculated for each of the two or more laser light sources, the temperature value and the concentration value with a small measurement error are output as the measurement result. As a result, the concentration and temperature of the analysis target gas can be accurately measured even in an environment in which the fluctuations in the temperature, concentration, and pressure of the analysis target gas change from moment to moment.

  A gas analyzer according to another aspect of the present disclosure measures the temperature and concentration of a gas to be analyzed. The gas analyzer detects, for each of the two or more laser light sources that emit laser light of different wavelengths, the absorption spectrum of the laser light emitted from the laser light source due to the analysis target gas. The detection unit, the selection unit, the calculation unit, and the output unit. The selection unit selects a selection light source from two or more laser light sources. The calculation unit calculates the temperature value, the concentration value, and the pressure value of the analysis target gas based on the absorption spectrum detected for the selected light source. The output unit outputs the temperature value, the concentration value, and the pressure value calculated by the calculation unit as a measurement result. The selection unit, of the two or more laser light sources, the measurement error of at least one of the temperature value and the concentration value under the environment indicated by the temperature value, the concentration value, and the pressure value indicated by the measurement result output last time by the output unit. Selects the laser light source with the minimum value as the selected light source.

  Even in an environment in which the temperature, concentration, and pressure of the gas to be analyzed fluctuate from moment to moment, if the measurement interval is set sufficiently short, the change from the previous measurement result will be small. Therefore, by selecting the laser light source with the smallest measurement error under the environment indicated by the temperature value, concentration value, and pressure value indicated by the previous measurement result as the selected light source, And the pressure value is output as the measurement result. As a result, the concentration and temperature of the analysis target gas can be accurately measured even in an environment in which the fluctuations in the temperature, concentration, and pressure of the analysis target gas change from moment to moment.

  Preferably, the selection unit calculates the measurement error for each of the two or more laser light sources based on the noise component of the absorption spectrum detected by the detection unit.

  According to the above configuration, it is possible to select a laser light source having a small measurement error due to the noise component of the absorption spectrum as the selection light source.

  Preferably, the gas analyzer further includes a storage unit that stores a selection map in which the pressure value, the temperature value, and the concentration value are associated with the laser light source with the smallest measurement error. The selection unit specifies the laser light source corresponding to the temperature value, the concentration value, and the pressure value indicated by the measurement result output last time by the output unit from the selection map, and selects the specified laser light source as the selection light source.

  According to the above configuration, by storing the selection map in advance, it is possible to reduce the load required for the selection unit to select the selected light source.

  Preferably, the gas analyzer further includes a temperature sensor that measures the temperature of the analysis target gas, a concentration sensor that measures the concentration of the analysis target gas, and a pressure sensor that measures the pressure of the analysis target gas. The output unit sequentially outputs the measurement results at predetermined measurement intervals. At the time of the first measurement, the output unit outputs the temperature value measured by the temperature sensor, the concentration value measured by the concentration sensor, and the pressure value measured by the pressure sensor as the measurement result. The output unit outputs the temperature value, the concentration value, and the pressure value calculated by the calculation unit as the measurement result during the second and subsequent measurements.

  At the start of measurement, the environment of the gas to be analyzed is often stable. Therefore, at the time of the first measurement, the temperature and the concentration of the analysis target gas can be accurately measured even if the temperature sensor and the concentration sensor having a long response time are used.

  Preferably, the output unit sequentially outputs the measurement result at a predetermined measurement interval. The selection unit selects a predetermined laser light source as a selection light source during the first measurement.

  At the start of measurement, the environment of the gas to be analyzed is often stable within a predetermined range. In this case, the temperature and concentration of the first time can be accurately measured by predefining a laser light source having a small measurement error under the environment of the predetermined range.

  Preferably, the selection unit specifies a plurality of laser light sources corresponding to the temperature value, the concentration value and the pressure value indicated by the measurement result output last time by the output unit from the selection map, and selects the specified laser light source as the selection light source. . The output unit outputs, as a measurement result, a value obtained by interpolation calculation from the temperature value, the concentration value, and the pressure value calculated by the calculation unit for each of the plurality of laser light sources.

  According to the above configuration, even if the temperature value, the concentration value, and the pressure value measured last time are deviated from the temperature value, the concentration value, and the pressure value of the selection map, the temperature and the concentration of the analysis target gas can be accurately measured. It can be measured.

  According to the present disclosure, it is possible to accurately measure the concentration and temperature of an analysis target gas even in an environment where the temperature, concentration, and pressure of the analysis target gas greatly vary.

1 is a schematic configuration diagram showing a gas analyzer according to the first embodiment. FIG. 3 is a block diagram showing an internal configuration of a control unit shown in FIG. 1. It is a figure which shows an example of a density calculation map. 3 is a flowchart showing a flow of processing of a control unit shown in FIG. 1. 7 is a block diagram showing an internal configuration of a control unit included in the gas analyzer according to the second embodiment. FIG. 6 is a flowchart showing a processing flow of a control unit shown in FIG. 5. FIG. 6 is a schematic configuration diagram showing a gas analyzer according to a third embodiment. FIG. 8 is a block diagram showing an internal configuration of a control unit shown in FIG. 7. 9 is a flowchart showing the flow of processing of the control unit shown in FIG. 8. FIG. 9 is a block diagram showing an internal configuration of a control unit included in the gas analyzer according to the fourth embodiment. It is a figure which shows an example of a selection map. FIG. 16 is a block diagram showing an internal configuration of a control unit included in the gas analyzer according to the fifth embodiment. It is a figure which shows the time change of temperature value T1-T3 calculated by the calculating part shown in FIG. 12, and an actual temperature value and pressure value. It is a figure which shows the time change of the temperature value T output from the output part shown in FIG. 12, and the actual temperature value and pressure value. It is a figure which shows another example of a selection map. It is a figure which shows the determination method of a weighting factor.

  Embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the same or corresponding parts in the drawings are designated by the same reference numerals and description thereof will not be repeated. Further, the respective embodiments or modified examples described below may be combined as appropriate.

<Embodiment 1>
(Configuration of gas analyzer)
FIG. 1 is a schematic configuration diagram showing a gas analyzer 1A according to the first embodiment. The gas analyzer 1A is a device that analyzes a gas to be analyzed existing in the measurement chamber 10 by using a wavelength tunable semiconductor laser absorption spectroscopy (TDLAS). The measurement chamber 10 is, for example, a combustion chamber of an internal combustion engine. The analysis target gas is, for example, H ₂ O, CO, CO ₂ , O ₂ , NH ₃ , NO, NO ₂ , SO ₂ , HCl or the like.

  The temperature, concentration and pressure of the analysis target gas in the measurement chamber 10 change from moment to moment. The gas analyzer 1A measures the temperature, concentration, and pressure of the analysis target gas at a predetermined measurement interval Δt (for example, 50 μsec). The measurement interval Δt is a variation amount of the temperature, concentration and pressure of the analysis target gas in the measurement chamber 10 per unit time so that changes in the temperature, concentration and pressure of the analysis target gas can be continuously measured. It is set as appropriate.

  As shown in FIG. 1, the gas analyzer 1A includes a pressure sensor 11, four laser irradiation units 12a to 12d, four optical fibers 13a to 13d, four lenses 14a to 14d, and four lenses 15a. ˜15d, four optical fibers 16a to 16d, four light receiving units 17a to 17d, and a control unit 20A.

  The pressure sensor 11 is a sensor that measures the pressure of the gas to be analyzed in the measurement chamber 10. The response time of the pressure sensor 11 is shorter than the measurement interval Δt and is, for example, 1 μsec or less. As the pressure sensor 11, a known sensor whose response time is shorter than the measurement interval Δt can be used. The pressure sensor 11 outputs the measured pressure value P to the control unit 20A.

  The laser light 18a output from the laser irradiation unit 12a enters the light receiving unit 17a through the first optical path formed by the optical fiber 13a, the lens 14a, the measurement chamber 10, the lens 15a, and the optical fiber 16a. The laser beam 18b output from the laser irradiation unit 12b enters the light receiving unit 17b through the second optical path including the optical fiber 13b, the lens 14b, the measurement chamber 10, the lens 15b, and the optical fiber 16b. The laser light 18c output from the laser irradiation unit 12c enters the light receiving unit 17c through the third optical path formed by the optical fiber 13c, the lens 14c, the measurement chamber 10, the lens 15c, and the optical fiber 16c. The laser beam 18d output from the laser irradiation unit 12d enters the light receiving unit 17d through the fourth optical path including the optical fiber 13d, the lens 14d, the measurement chamber 10, the lens 15d, and the optical fiber 16d. In this way, the laser lights output from the four laser irradiation units 12a to 12d respectively pass through the first to fourth optical paths different from each other.

  The laser irradiation unit 12a includes a laser light source 121a, a lens 122, and a D / A converter 123.

  The D / A converter 123 converts the digital-format drive signal received from the control unit 20A into an analog signal.

  The laser light source 121a is composed of a laser diode. The laser light source 121a emits laser light 18a according to the analog signal output from the D / A converter 123. The wavelength of the laser light 18a output from the laser light source 121a is modulated according to the modulation frequency of the analog signal output from the D / A converter 123. The center wavelength λa of the laser light 18a output from the laser light source 121a matches one of the absorption wavelengths of the gas to be analyzed.

  The lens 122 collects the laser light 18a output from the laser light source 121a and makes it enter the optical fiber 13a.

The laser irradiation unit 12b differs from the laser irradiation unit 12a in that the laser irradiation unit 12b includes a laser light source 121b instead of the laser light source 121a. The laser irradiation unit 12c differs from the laser irradiation unit 12a in that the laser irradiation unit 12c includes a laser light source 121c instead of the laser light source 121a. The laser irradiation unit 12d differs from the laser irradiation unit 12a in that it includes a laser light source 121d instead of the laser light source 121a. Similar to the laser light source 121a, the laser light sources 121b to 121d emit laser light 18b to 18d according to the analog signal output from the D / A converter 123, respectively. The wavelengths of the laser beams 18b to 18d output from the laser light sources 121b to 121d are respectively modulated according to the modulation frequency of the analog signal output from the corresponding D / A converter 123. The center wavelength λb of the laser light 18b, the center wavelength λc of the laser light 18c, and the center wavelength λd of the laser light 18d match one of the absorption wavelengths of the gas to be analyzed. However, the central wavelengths λa, λb, λc, and λd are different from each other. When the gas to be analyzed is H ₂ O, the central wavelengths λa, λb, λc, and λd are, for example, 1392 nm (wavenumber 7185.6 cm ⁻¹ ), 1385 nm (wavenumber 7219.6 cm ⁻¹ ) and 1371 nm (wavenumber 7294. 2cm ^-1), it is a 1343nm (wave number 7444.4cm ^-1).

  The lenses 14 a to 14 d are collimating lenses arranged on the side wall of the measurement chamber 10. Each of the lenses 14a to 14d collimates the laser light incident from the corresponding optical fiber. The parallel light from the lenses 14 a to 14 d passes through the inside of the measurement chamber 10.

  The lenses 15 a to 15 d are condenser lenses arranged on the side wall of the measurement chamber 10. Each of the lenses 15a to 15d collects the corresponding laser light transmitted through the measurement chamber 10 and guides it to the corresponding optical fiber.

  Each of the light receiving units 17a to 17d includes a condenser lens 171, a light receiving element 172, and an A / D converter 173. The condenser lens 171 is a lens for condensing the laser light from the corresponding optical fiber on the light receiving element 172. The light receiving element 172 outputs an analog signal according to the amount of received light. The A / D converter 173 converts the analog signal from the light receiving element 172 into a digital signal and outputs it to the control unit 20A.

  The control unit 20A controls the digital signal output to each of the laser irradiation units 12a to 12d. Further, the control unit 20A measures the concentration and temperature of the analysis target gas in the measurement chamber 10 based on the digital signal output from each of the light receiving units 17a to 17d and the pressure value P from the pressure sensor 11, The density value C and the temperature value T, which are the measurement results, are output.

  The control unit 20A includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). Note that these parts are connected to each other via an internal bus. The CPU expands the program stored in the ROM into the RAM and executes the program. The program stored in the ROM is a program in which the processing method of the control unit 20A is described.

(Configuration of control unit)
FIG. 2 is a block diagram showing the internal configuration of the control unit. As shown in FIG. 2, the control unit 20A includes a drive unit 21, a detection unit 22, a storage unit 23A, a calculation unit 24A, a selection unit 25A, and an output unit 26A.

  The drive unit 21 outputs a drive signal modulated according to a predetermined modulation frequency f to each of the laser irradiation units 12a to 12d. As a result, the laser irradiation units 12a to 12d respectively output the laser lights 18a to 18d wavelength-modulated at the modulation frequency f.

  The detection unit 22 detects the light absorption information of each of the laser beams 18a to 18d by the analysis target gas at a predetermined measurement interval Δt. The detector 22 receives digital signals from the light receivers 17a to 17d. The digital signal received from each of the light receiving units 17a to 17d is a transmittance spectrum. The detection unit 22 obtains the 2f signal by processing the digital signal using the double harmonic of the modulation frequency f as a reference wave.

  The detection unit 22 detects the peak value (2f peak value) of the 2f signal obtained from the digital signals output from each of the light receiving units 17a to 17d as the light absorption information.

  The 2f peak value is almost proportional to the absorbance of the peak of the absorption spectrum when the transmittance of the gas to be analyzed is close to 1. The 2f peak value changes not only with the concentration of the analysis target gas, but also with the temperature and pressure of the analysis target gas. Therefore, the temperature and concentration of the gas to be analyzed can be measured by confirming the 2f peak value.

  Below, the 2f peak value obtained from the signal output from the light receiving unit 17a is referred to as "2f peak value I1a", and the 2f peak value obtained from the signal output from the light receiving unit 17b is referred to as "2f peak value I1b". The 2f peak value obtained from the signal output from the unit 17c is referred to as "2f peak value I1c", and the 2f peak value obtained from the signal output from the light receiving unit 17d is referred to as "2f peak value I1d".

  The storage unit 23A stores four noise components Na to Nd, four density calculation maps MCa to MCd, and three temperature calculation maps MT1 to MT3.

  The noise components Na to Nd indicate the amplitude of noise generated in the 2f signal due to electrical or optical causes in the light receiving units 17a to 17d and the detection unit 22, respectively, and are measured in advance by experiments and stored in the storage unit 23A. It

  The density calculation maps MCa to MCd correspond to the laser lights 18a to 18d, respectively. The concentration calculation map MCa is a map showing the relationship between the 2f peak value I0a that can be output from the detection unit 22 according to the laser beam 18a, the temperature of the analysis target gas, and the pressure of the analysis target gas at a concentration of a certain representative value. Is. The concentration calculation map MCb is a map showing the relationship between the 2f peak value I0b that can be output from the detection unit 22 according to the laser beam 18b, the temperature of the analysis target gas, and the pressure of the analysis target gas at a concentration of a certain representative value. Is. The concentration calculation map MCc is a map showing the relationship between the 2f peak value I0c that can be output from the detection unit 22 according to the laser beam 18c, the temperature of the analysis target gas, and the pressure of the analysis target gas at a concentration of a certain representative value. Is. The concentration calculation map MCd is a map showing the relationship between the 2f peak value I0d that can be output from the detection unit 22 according to the laser beam 18d, the temperature of the analysis target gas, and the pressure of the analysis target gas at a concentration of a certain representative value. Is. The density calculation maps MCa to MCd are created in advance and stored in the storage unit 23A.

  The temperature calculation maps MT1 to MT3 correspond to each of three predetermined laser light source pairs. The three laser light source pairs are appropriately set according to the type of gas to be analyzed, the wavelengths of the laser lights 18a to 18d emitted from the laser light sources 121a to 121d, and the concentration calculation maps MCa to MCd. In the present embodiment, the case where the temperature calculation maps MT1 to MT3 are as follows will be described as an example. That is, the temperature calculation map MT1 corresponds to a pair of the laser light source 121a and the laser light source 121b (hereinafter, referred to as “laser light source pair Pa1”). The temperature calculation map MT2 corresponds to a pair of the laser light source 121b and the laser light source 121d (hereinafter, referred to as “laser light source pair Pa2”). The temperature calculation map MT3 corresponds to a pair of the laser light source 121c and the laser light source 121d (hereinafter, referred to as “laser light source pair Pa3”).

  The temperature calculation map MT1 includes a ratio R0_1 of the 2f peak value I0a that can be output from the detection unit 22 according to the laser beam 18a and the 2f peak value I0b that can be output from the detection unit 22 according to the laser beam 18b, and the gas to be analyzed. 3 is a map showing the relationship between the pressure of 1 and the temperature of the gas to be analyzed. The temperature calculation map MT2 includes a ratio R0_2 of the 2f peak value I0b that can be output from the detection unit 22 according to the laser light 18b and the 2f peak value I0d that can be output from the detection unit 22 according to the laser light 18d, and the gas to be analyzed. 3 is a map showing the relationship between the pressure of 1 and the temperature of the gas to be analyzed. The temperature calculation map MT3 includes a ratio R0_3 of the 2f peak value I0c that can be output from the detection unit 22 according to the laser light 18c and the 2f peak value I0d that can be output from the detection unit 22 according to the laser light 18d, and the gas to be analyzed. 3 is a map showing the relationship between the pressure of 1 and the temperature of the gas to be analyzed. The temperature calculation maps MT1 to MT3 are created in advance based on the concentration calculation maps MCa to MCd and stored in the storage unit 23A.

  The calculation unit 24A calculates the temperature value and the concentration value of the analysis target gas at a predetermined measurement interval Δt. The calculator 24A calculates the temperature value T1 and the concentration value C1 of the gas to be analyzed for the laser light source pair Pa1. Similarly, the calculation unit 24A calculates the temperature value T2 and the concentration value C2 of the analysis target gas for the laser light source pair Pa2. Similarly, the calculation unit 24A calculates the temperature value T3 and the concentration value C3 of the analysis target gas for the laser light source pair Pa3.

  The selection unit 25A selects one laser light source pair from the laser light source pairs Pa1 to Pa3 as a selected pair based on the temperature values T1 to T3, the concentration values C1 to C3, and the pressure value P calculated by the calculation unit 24A. select. The selection unit 25A outputs the selection result information M indicating the selected pair to the output unit 26A.

  Out of the calculated temperature values T1 to T3 and the concentration values C1 to C3, the output unit 26A outputs the temperature values and the concentration values calculated for the selected pair indicated by the selection result information M as the measurement results (the temperature values T and Output as density value C). The output unit 26A also outputs the pressure value P measured by the pressure sensor 11 as a measurement result.

(Density calculation map)
FIG. 3 is a diagram showing an example of the density calculation map. In FIG. 3, and analyzed gas _{H 2} O, when a representative value is the concentration of _{H 2} O, and 2f peak values corresponding to the laser beam having a wavelength of 1343Nm (wavenumber 7444.4cm ^-1), H and temperature _{2 O,} concentration calculation map showing the relationship between the pressure of H 2 _O is shown.

  When the temperature value and the pressure value are designated in the concentration calculation map as shown in FIG. 3, the 2f peak value corresponding to the temperature value and the pressure value can be derived. The 2f peak value derived from the density calculation map is a peak value when the density is a representative value. When the transmittance is close to 1, the 2f peak value is almost proportional to the concentration value of the gas to be analyzed. Therefore, the concentration value of the analysis target gas is calculated based on the ratio between the 2f peak value detected by the detection unit 22 and the 2f peak value derived from the concentration calculation map and the representative value of the concentration corresponding to the concentration calculation map. It can be calculated.

(Temperature calculation map)
The temperature and pressure dependence of the 2f peak value when the concentration has a certain representative value (see FIG. 3) differs depending on the wavelength of the laser light. As described above, the 2f peak value is almost proportional to the density value when the transmittance is close to 1. Therefore, the ratio of the 2f peak value corresponding to the laser light of a certain wavelength and the 2f peak value corresponding to the laser light of another wavelength does not depend on the concentration but depends on the temperature and the pressure of the gas to be analyzed. . Therefore, based on the two concentration calculation maps respectively corresponding to the two laser beams of different wavelengths, the ratio of the 2f peak value corresponding to each of the two laser beams, the temperature of the analysis target gas, and the analysis target gas A temperature calculation map showing the relationship with pressure can be created.

  Therefore, the temperature calculation map MT1 is created based on the density calculation map MCa corresponding to the laser light 18a and the density calculation map MCc corresponding to the laser light 18c. The temperature calculation map MT2 is created based on the density calculation map MCb corresponding to the laser light 18b and the density calculation map MCd corresponding to the laser light 18d. The temperature calculation map MT3 is created based on the density calculation map MCc corresponding to the laser light 18c and the density calculation map MCd corresponding to the laser light 18d.

  By using the temperature calculation map, the temperature of the analysis target gas can be calculated by designating the ratio of the two 2f peak values and the pressure value.

(Calculation method of temperature value and concentration value by calculation unit)
As described above, the calculation unit 24A calculates the temperature value and the concentration value of the analysis target gas for each of the laser light source pairs Pa1 to Pa3. Hereinafter, a method of calculating the temperature value T1 and the concentration value C1 for the laser light source pair Pa1 (a pair of the laser light source 121a and the laser light source 121c) will be described as an example.

  The calculation unit 24A acquires the 2f peak value I1a corresponding to the laser light source 121a and the 2f peak value I1c corresponding to the laser light source 121c from the detection unit 22. Further, the calculation unit 24A acquires the pressure value P measured by the pressure sensor 11.

  The calculator 24A calculates a ratio R1_1 between the 2f peak value I1a and the 2f peak value I1c. The calculation unit 24A obtains the temperature value T1 corresponding to the calculated ratio R1_1 and the pressure value P using the temperature calculation map MT1 corresponding to the laser light source pair Pa1.

  The calculation unit 24A specifies the 2f peak value I0a corresponding to the temperature value T1 and the pressure value P from the concentration calculation map MCa corresponding to the one laser light source 121a of the laser light source pair Pa1. The calculator 24A sets the density value C1a calculated based on the ratio between the 2f peak value I1a detected by the detector 22 and the 2f peak value I0a specified from the density calculation map MCa as the density value C1.

  Alternatively, the calculation unit 24A may specify the 2f peak value I0c corresponding to the temperature value T1 and the pressure value P from the concentration calculation map MCc corresponding to the other laser light source 121c of the laser light source pair Pa1. Then, the calculation unit 24A may set the concentration value C1c calculated based on the ratio between the 2f peak value I1c detected by the detection unit 22 and the 2f peak value I0c specified from the concentration calculation map MCc, as the concentration value C1.

  Alternatively, the calculation unit 24A may calculate the average value of the density value C1a and the density value C1c as the density value C1.

  The calculation unit 24A calculates the temperature value T2 and the concentration value C2 and the temperature value T3 and the concentration value C3 by the same calculation method as described above.

(How to select a selected pair by the selector)
The selection unit 25A calculates the measurement error of at least one of the temperature value and the concentration value calculated by the calculation unit 24A for each of the laser light source pairs Pa1 to Pa3 based on the noise components Na to Nd stored in the storage unit 23A. Then, the laser light source pair with the smallest calculated measurement error is selected as the selected pair. For example, the selection unit 25A selects the laser light source pair with the smallest temperature value measurement error as the selected pair. Alternatively, the selection unit 25A may select the laser light source pair with the smallest concentration value measurement error as the selected pair. Alternatively, the selection unit 25A may select the laser light source pair having the smallest sum of the temperature value measurement error and the concentration value measurement error as the selected pair. As described above, the calculation unit 24A first calculates the temperature value T and then calculates the concentration value C1 using the calculated temperature value T1. Therefore, it is preferable that the selection unit 25A selects the laser light source pair having the smallest temperature value measurement error as the selected pair.

  The method of calculating the measurement error of the temperature value T1 and the density value C1 calculated for the laser light source pair Pa1 will be described below. An example will be described in which the density value C1a calculated based on the ratio between the 2f peak value I1a detected by the detection unit 22 and the 2f peak value I0a specified from the density calculation map MCa is calculated as the density value C1. .

The selection unit 25A reads the noise components Na and Nc corresponding to the laser light sources 121a and 121c included in the laser light source pair Pa1 from the storage unit 23A. From the read noise component Na and the 2f peak value I1a and the 2f peak value I1c detected by the detection unit 22, the selection unit 25A calculates the standard error R1_1E included in I1a / I1c from the propagation of the standard error ((Na / I1a) ² + (Nc / I1c) ² ) ^1/2 * (I1a / I1c), and I1a / I1c + R1_1E are calculated as R1_1E1 and I1a / I1c-R1_1E are calculated as R1_1E2.

  The selection unit 25A obtains the temperature value TpE1 corresponding to the ratio R1_1E1 and the pressure value P from the temperature calculation map MT1. Similarly, the selection unit 25A obtains the temperature value TpE2 for the ratio R1_1E2. Then, the selection unit 25A may set the maximum value or the average thereof as the measurement error included in the temperature T1.

  Next, the selection unit 25A specifies the 2f peak value I0a corresponding to the temperature value T1 and the pressure value P from the concentration calculation map MCa. The selection unit 25A, based on the ratio (= (I1a + Na) / I0a) of the specified 2f peak value I0a and the value (I1a + Na) obtained by adding the noise component Na to the 2f peak value I1a detected by the detection unit 22, The density value Cp1 is calculated. Furthermore, the selection unit 25A has a ratio (= (I1a-Na) / of the specified 2f peak value I0a and a value (I1a-Na) obtained by subtracting the noise component Na from the 2f peak value I1a detected by the detection unit 22. The density value Cq1 is calculated based on I0a.

  The selection unit 25A may calculate the maximum value or the average value of the differences between the density value C1 and each of the density values Cp1 and Cq1 as the measurement error of the density value C1.

  The larger the 2f peak value, the larger the SN ratio. However, the larger the SN ratio, the smaller the measurement error of the temperature value and the concentration value does not mean. As shown in FIG. 3, the interval between the contour lines of the 2f peak value in the concentration calculation map varies depending on the pressure and the temperature. In the concentration calculation map, even if the 2f peak value is large, in a region where the change of the 2f peak value is small with respect to the change of the temperature, the temperature calculated by the calculation unit 24A is greatly affected by the noise of the 2f peak value. That is, the measurement error of the temperature value becomes large. On the contrary, in the concentration calculation map, even if the 2f peak value is small, in a region where the change of the 2f peak value is large with respect to the change of the temperature, the temperature calculated by the calculation unit 24A has a great influence on the noise of the 2f peak value. Not done. That is, the measurement error of the temperature value is reduced. Therefore, the selection unit 25A selects the selected pair by calculating the measurement error as described above without using only the SN ratio. As a result, the selection unit 25A can select a laser light source pair in which the change in the 2f peak value with respect to changes in temperature and pressure is as large as possible and the 2f peak value is sufficiently larger than noise as a selected pair.

(Processing flow of control unit)
Next, the flow of processing of the control unit 20A will be described with reference to FIG. FIG. 4 is a flowchart showing the flow of processing of the control unit.

  First, in step S11, the calculation unit 24A acquires the 2f peak values I1a to I1d corresponding to the laser light sources 121a to 121d from the detection unit 22. Next, in step S12, the calculation unit 24A acquires the pressure value P measured by the pressure sensor 11. Next, in step S13, the calculation unit 24A calculates temperature values T1 to T3 and concentration values C1 to C3 for the laser light source pairs Pa1 to Pa3, respectively.

  Next, in step S14, the selection unit 25A selects one of the laser light source pairs Pa1 to Pa3 as a selected pair, and generates selection result information M indicating the selected pair. Specifically, the selection unit 25A measures at least one of the temperature value and the concentration value calculated for each of the laser light source pairs Pa1 to Pa3 based on the noise components Na to Nd stored in the storage unit 23A. To calculate. The selection unit 25A selects the laser light source pair having the smallest calculated measurement error as the selected pair. The selection unit 25A generates selection result information M indicating "1" when the laser light source pair Pa1 is selected as a selection pair, and indicates selection result information M indicating "2" when the laser light source pair Pa2 is selected as a selection pair. M is generated, and the selection result information M indicating “3” is generated when the laser light source pair Pa3 is selected as the selected pair.

  Next, in step S15, the output unit 26A confirms the selection result information M. When the selection result information M = “1”, the output unit 26A measures the temperature value T1 and the concentration value C1 calculated for the laser light source pair Pa1 in step S16 (the temperature value T and the concentration value C). To decide. When the selection result information M = “2”, the output unit 26A measures the temperature value T2 and the concentration value C2 calculated for the laser light source pair Pa2 in step S17 (the temperature value T and the concentration value C). To decide. When the selection result information M = “3”, the output unit 26A measures the temperature value T3 and the concentration value C3 calculated for the laser light source pair Pa3 in step S18 (the temperature value T and the concentration value C). To decide. After that, in step S19, the output unit 26A outputs the measurement results (pressure value P, temperature value T, and concentration value C).

  Next, in step S20, the control unit 20A determines whether or not an instruction to end the measurement is received. When the measurement end instruction is received, the control unit 20A ends the process.

  If the instruction to end the measurement has not been received, the control unit 20A determines in step S21 whether or not the measurement interval Δt has elapsed since the start of step S11. If the measurement interval Δt has not elapsed (NO in step S21), the process returns to step S21. When the measurement interval Δt has elapsed (YES in step S21), the processes of steps S11 to S20 are repeated.

(advantage)
As described above, the gas analyzer 1A includes the calculation unit 24A, the selection unit 25A, and the output unit 26A. For each of the laser light source pairs Pa1 to Pa3, the calculation unit 24A determines that the 2f peak value (first absorption information) detected by the detection unit 22 for one laser light source of the laser light source pair and the detection unit 22 for the other laser light source. Based on at least one of the detected 2f peak value (second absorption information), the ratio of these two 2f peak values, and the pressure value P, the temperature value and the concentration value of the gas to be analyzed are calculated. The selection unit 25A selects a selected pair from the laser light source pairs Pa1 to Pa3. The output unit 26A outputs the temperature value and the concentration value calculated by the calculation unit 24A for the selected pair as the measurement result. The selection unit 25A measures at least one of the temperature value and the concentration value calculated by the calculation unit 24A for each of the laser light source pairs Pa1 to Pa3 based on the noise component of the 2f peak value detected by the detection unit 22. To calculate. The selection unit 25A selects the laser light source pair having the smallest calculated measurement error as the selected pair.

  According to the above configuration, of the temperature value and the concentration value calculated for each of the laser light source pairs Pa1 to Pa3, the temperature value and the concentration value with a small measurement error are output as the measurement result. As a result, the concentration and temperature of the analysis target gas can be accurately measured even in an environment in which the fluctuations in the temperature, concentration, and pressure of the analysis target gas change from moment to moment.

<Second Embodiment>
(Configuration of gas analyzer)
A gas analyzer according to the second embodiment will be described with reference to FIG. FIG. 5 is a block diagram showing an internal configuration of the control unit 20B included in the gas analyzer according to the second embodiment. The gas analyzer according to the second embodiment is different from the gas analyzer 1A according to the first embodiment only in that a control unit 20B shown in FIG. 5 is provided instead of the control unit 20A. As shown in FIG. 5, the control unit 20B is different from the control unit 20A (see FIG. 2) of the first embodiment in that instead of the storage unit 23A, the selection unit 25A and the output unit 26A, the control unit 20B selects the selection. The only difference is that the section 25B and the output section 26B are included. Since other points are the same as those of control unit 20A shown in FIG. 2, description thereof will not be repeated below.

  The storage unit 23B stores the noise components Na to Nd, the density calculation maps MCa to MCd, the temperature calculation maps MT1 to MT3, and the measurement result information D.

  The measurement result information D is information indicating the pressure value P, the temperature value T, and the concentration value C that the output unit 26B previously output.

  Output unit 26B performs the same process as output unit 26A of the first embodiment, and further performs an update process of measurement result information D stored in storage unit 23B. When outputting the temperature value and the concentration value corresponding to the selected pair as the measurement result, the output unit 26B follows the measurement result (the temperature value T and the concentration value C) and the pressure value P measured by the pressure sensor 11. The measurement result information D stored in the storage unit 23B is updated.

  The selection unit 25B selects a predetermined laser light source pair as a selected pair in the first measurement at the start of measurement. The environment of the measurement chamber 10 is often in a stable state at the start of measurement. Therefore, the environment of the measurement room 10 at the time of starting the measurement may be investigated in advance, and the laser light source pair suitable for the environment may be determined.

  The selection unit 25B selects a selected pair as follows in the second and subsequent measurements after the start of measurement. When the pressure value P, the temperature value T, and the concentration value C indicated by the measurement result information D are selected, the selection unit 25B measures at least one of the temperature value and the concentration value calculated from each of the laser light source pairs Pa1 to Pa3. To calculate. The selection unit 25B selects the laser light source pair having the smallest calculated measurement error as the selected pair. As described above, the measurement interval Δt is appropriately set so that changes in the temperature, concentration, and pressure of the gas to be analyzed can be continuously measured. Therefore, the respective differences between the pressure value P, the temperature value T and the concentration value C measured this time and the pressure value P, the temperature value T and the concentration value C measured the previous time are small. Therefore, the selection unit 25B selects the laser light source pair having the smallest measurement error at the pressure value P, the temperature value T, and the concentration value C indicated by the measurement result information D as the selected pair.

  Similar to the first embodiment, the selection unit 25B may select the laser light source pair with the smallest temperature value measurement error as the selected pair, or the laser light source pair with the smallest concentration value measurement error as the selected pair. You may choose. Alternatively, the selection unit 25B may select the laser light source pair having the smallest sum of the measurement error of the temperature value and the measurement error of the concentration value as the selected pair.

  A method of calculating the measurement error of the temperature value and the density value calculated from the laser light source pair Pa1 when the pressure value P, the temperature value T and the density value C indicated by the measurement result information D are described below. The pressure value P indicated by the measurement result information D is "previous pressure value P", the temperature value T indicated by the measurement result information D is "previous temperature value T", and the concentration value C indicated by the measurement result information D is "previous concentration". Value C ”.

The selection unit 25B reads from the storage unit 23B the noise components Na and Nc corresponding to the laser light sources 121a and 121c included in the laser light source pair Pa1. The selection unit 25B identifies the 2f peak value I2a corresponding to the previous temperature value T and the previous pressure value P from the concentration calculation map MCa. Further, the selection unit 25B specifies the 2f peak value I2c corresponding to the previous temperature value T and the previous pressure value P from the concentration calculation map MCc. The selection unit 25B calculates the standard error R2_2E included in I2a / I2c from the read noise component Na and the specified 2f peak value I2a and 2f peak value I2c from the propagation of the standard error ((Na / I2a) ² + ( Nc / I2c) ² ) ^1/2 * (I2a / I2c), and I2a / I2c + R2_2E are calculated as R2_2E1 and I2a / I2c-R2_2E are calculated as R2_2E2.

  The selection unit 25B obtains the temperature value TpE1 corresponding to the ratio R2_2E1 and the pressure value P from the temperature calculation map MT1. Similarly, the selection unit 25B calculates the temperature value TpE2 for the ratio R1_1E2. Then, the selection unit 25B may calculate the maximum value or the average value thereof as a measurement error included in the temperature value when the laser light source pair Pa1 is used.

  Next, the selection unit 25B calculates the density value Cp2 based on the ratio (= (I2a + Na) / I2a) of the 2f peak value I2a and the value (I2a + Na) obtained by adding the noise component Na to the 2f peak value I2a. . Further, the selection unit 25B determines the density value Cq2 based on the ratio (= (I2a-Na) / I2a) between the 2f peak value I2a and the value (I2a-Na) obtained by subtracting the noise component Na from the 2f peak value I2a. To calculate.

  The selection unit 25B may calculate the maximum value of the differences between the previous density value C and the density values Cp2 and Cq2, or the measurement error included in the density value when the laser light source pair Pa1 is used.

(Processing flow of control unit)
Next, a processing flow of the control unit 20B will be described with reference to FIG. FIG. 6 is a flowchart showing the flow of processing of the control unit 20B. As shown in FIG. 6, as compared with the processing flow of the control unit 20A shown in FIG. 4, the processing flow of the control unit 20B performs steps S31 to S33 instead of step S14, and instead of step S19. The only difference is that step S34 is performed.

  In step S31, the selection unit 25B determines whether it is the first measurement. If it is the first measurement (YES in step S31), the selection unit 25B selects a predetermined laser light source pair as a selected pair in step S32.

  If it is not the first measurement (NO in step S31), the selection unit 25B calculates the measurement result indicated by the measurement result information D in step S33 for each of the laser light source pairs Pa1 to Pa3. A measurement error of at least one of the temperature value and the concentration value is calculated. The selection unit 25B selects the laser light source pair having the smallest calculated measurement error as the selected pair.

  In step S34, the output unit 26B outputs the measurement result (pressure value P, temperature value T, and concentration value C), and updates the measurement result information D stored in the storage unit 23B according to the measurement result.

(advantage)
As described above, the gas analyzer according to the second embodiment includes the selection unit 25B, the calculation unit 24A, and the output unit 26B. The selection unit 25B selects a selected pair from the laser light source pairs Pa1 to Pa3. The calculation unit 24A includes a 2f peak value (first absorption information) detected by the detection unit 22 for one of the laser light sources included in the selected pair and a 2f peak value (second absorption information for the other laser light source) detected by the detection unit 22. ), The ratio of these two 2f peak values, and the pressure value P, the temperature value and the concentration value of the gas to be analyzed are calculated. The output unit 26B outputs the temperature value and the concentration value calculated by the calculation unit 24A for the selected pair as the measurement result. Of the laser light source pairs Pa1 to Pa3, the selection unit 25B is a laser with a minimum measurement error of at least one of the temperature value and the concentration value under the environment indicated by the previous temperature value T, the previous concentration value C, and the previous pressure value P. Select the light source pair as the selected pair.

  Even in an environment in which the temperature, concentration, and pressure of the gas to be analyzed fluctuate momentarily, if the measurement interval Δt is set sufficiently short, the change from the previous measurement result will be small. Therefore, the laser light source pair having the minimum measurement error under the environment indicated by the previous temperature value T, the previous concentration value C, and the previous pressure value P is selected as the selected pair, and thus the temperature value and the concentration value with the small measurement error are selected. Is output as the measurement result. As a result, the concentration and temperature of the analysis target gas can be accurately measured even in an environment in which the fluctuations in the temperature, concentration, and pressure of the analysis target gas change from moment to moment.

  The selection unit 25B calculates the measurement error for each of the laser light source pairs Pa1 to Pa3 based on the noise components Na to Nd of the 2f peak value detected by the detection unit 22. Thereby, the laser light source pair having a small measurement error due to the noise components Na to Nd of the 2f peak value is selected as the selected pair.

  The output unit 26B sequentially outputs the measurement results at a predetermined measurement interval Δt. The selection unit 25B selects a predetermined laser light source pair as a selected pair during the first measurement. At the start of measurement, the environment of the gas to be analyzed is often stable within a predetermined range. In this case, the temperature and the concentration of the first time can be accurately measured by predefining the laser light source pair having a small measurement error under the environment of the predetermined range.

<Third Embodiment>
(Configuration of gas analyzer)
The gas analyzer according to the third embodiment is a modification of the gas analyzer according to the second embodiment. A gas analyzer 1C according to the third embodiment will be described with reference to FIGS. 7 to 9. FIG. 7 is a schematic configuration diagram showing a gas analyzer 1C according to the third embodiment. FIG. 8 is a block diagram showing an internal configuration of the control unit 20C included in the gas analyzer 1C. As shown in FIG. 7, the gas analyzer 1C further includes a temperature sensor 31 and a concentration sensor 32 as compared with the gas analyzer according to the second embodiment, and includes a controller 20C instead of the controller 20B. The difference is in the provision. As shown in FIG. 8, the control unit 20C compares the control unit 20B of the second embodiment (see FIG. 5) with the calculation unit 24C, the selection unit 25B, and the output unit 26B instead of the calculation unit 24C. The only difference is that it includes a section 25C and an output section 26C. Since the other points are the same as those of control unit 20B shown in FIG. 5, description thereof will not be repeated below.

  The temperature sensor 31 is composed of, for example, a thermocouple. The response time of the temperature sensor 31 is longer than the measurement interval Δt.

  The concentration sensor 32 is composed of, for example, a zirconia sensor. The response time of the concentration sensor 32 is longer than the measurement interval Δt.

  The arithmetic unit 24C performs the same processing as the arithmetic unit 24A except for the first measurement. The arithmetic unit 24C acquires the pressure value measured by the pressure sensor 11, the temperature value measured by the temperature sensor 31, and the concentration value measured by the concentration sensor 32 during the first measurement. The arithmetic unit 24C outputs the acquired pressure value, temperature value and concentration value to the output unit 26C as the first measurement result (pressure value P, temperature value T and concentration value C).

  The output unit 26C performs the same process as the output unit 26B except for the first measurement. The output unit 26C outputs the first measurement result (pressure value P, temperature value T, and concentration value C) received from the arithmetic unit 24C as it is, and the measurement result stored in the storage unit 23B based on the measurement result. Information D is updated. At the start of measurement, the environment inside the measurement chamber 10 is often stable. Therefore, the reliability is high even if the temperature value and the concentration value are respectively obtained from the temperature sensor 31 and the concentration sensor 32 having a long response time.

  The selection unit 25C does not perform the selection process of the selected pair in the first measurement, but performs the selection process of the selected pair in the second and subsequent measurements. The selection processing method of the selection pair in the selection unit 25C is the same as the selection processing method in the second and subsequent measurements of the selection unit 25B of the second embodiment.

(Processing flow of control unit)
Next, a processing flow of the control unit 20C will be described with reference to FIG. FIG. 9 is a flowchart showing the flow of processing of the control unit 20C.

  First, in step S41, the calculation unit 24C acquires the pressure value, the temperature value, and the concentration value from the pressure sensor 11, the temperature sensor 31, and the concentration sensor 32, respectively. Next, in step S42, the output unit 26C outputs the pressure value, the temperature value, and the concentration value acquired in step S31 as the first measurement result, and updates the measurement result information D.

  Next, in step S43, the control unit 20C determines whether or not the measurement interval Δt has elapsed after starting step S41. If the measurement interval Δt has not elapsed (NO in step S43), the process returns to step S43. When the measurement interval Δt has elapsed (YES in step S43), the control unit 20C performs the processing in steps S11 to S13, S33, S15 to S18, S34, and S20 described in the first or second embodiment (see FIGS. 4 and 6). ).

  When the instruction to end the measurement is received (YES in step S20), control unit 20C ends the process. If the instruction to end the measurement has not been received (NO in step S20), the process returns to step S43. At this time, the control unit 20C determines whether or not the measurement interval Δt has elapsed since the start of step S11.

(advantage)
As described above, the gas analyzer 1C includes the temperature sensor 31 that measures the temperature of the analysis target gas and the concentration sensor 32 that measures the concentration of the analysis target gas. The output unit 26C sequentially outputs the measurement results at a predetermined measurement interval Δt. The output unit 26C uses the temperature value T measured by the temperature sensor 31, the concentration value C measured by the concentration sensor 32, and the pressure value P measured by the pressure sensor 11 as the measurement results during the first measurement. Output. The output unit 26C outputs the temperature value and the concentration value calculated by the calculation unit 24C for the selected pair as the measurement result during the second and subsequent measurements.

  At the start of measurement, the environment of the gas to be analyzed is often stable. Therefore, at the time of the first measurement, the temperature and the concentration of the analysis target gas can be accurately measured even if the temperature sensor and the concentration sensor having a long response time are used.

<Embodiment 4>
FIG. 10 is a block diagram showing the internal configuration of the control unit 20D included in the gas analyzer according to the fourth embodiment. The gas analyzer according to the fourth embodiment is a modification of the gas analyzer according to the second embodiment, and is shown in FIG. 10 instead of the control unit 20B as compared with the gas analyzer according to the second embodiment. The difference is that a control unit 20D is provided. As shown in FIG. 10, the control unit 20D includes a storage unit 23D instead of the storage unit 23B and a selection unit 25B instead of the control unit 20B of the second embodiment (see FIG. 5). The only difference is that the selection unit 25D is included. Since the other points are the same as those of control unit 20B shown in FIG. 5, description thereof will not be repeated below.

  The storage unit 23D further stores a selection map MS in addition to the concentration calculation maps MCa to MCd, the temperature calculation maps MT1 to MT3, and the measurement result information D. The selection map MS is a map showing a correspondence relationship among a plurality of representative pressure values of the analysis target gas, a plurality of representative temperature values of the analysis target gas, a plurality of representative concentration values of the analysis target gas, and a laser light source pair. . The laser light source pair shown in the selection map MS is a pair in which at least one of the temperature value and the concentration value has the smallest measurement error in the corresponding representative pressure value, representative temperature value, and representative concentration value. The selection map MS is created in advance by calculating the measurement error of the temperature value and the concentration value according to the representative pressure value, the representative temperature value and the representative concentration value, using the same method as in the second embodiment.

  FIG. 11 is a diagram showing an example of the selection map MS. FIG. 11 shows a correspondence relationship between a representative pressure value and a representative temperature value at a certain representative concentration value and a laser light source pair. FIG. 11 shows that, for example, when the representative pressure value is 1 atm and the representative temperature value is 300 K, the measurement error of the temperature value and the concentration value measured using the laser light source pair Pa3 is the smallest. .

  Similar to the selecting unit 25B of the second embodiment, the selecting unit 25D selects a predetermined laser light source pair as a selected pair in the first measurement at the start of measurement.

  The selection unit 25D selects the selected pair as follows in the second and subsequent measurements. That is, the selection unit 25D identifies the laser light source pair corresponding to the previous pressure value P, the previous temperature value T, and the previous concentration value C indicated by the measurement result information D from the selection map MS, and selects the identified laser light source pair. To choose as. Specifically, the selection unit 25D identifies the representative pressure value closest to the previous pressure value P, the representative temperature value closest to the previous temperature value T, and the representative concentration value closest to the previous concentration value C, and the identified representative pressure The laser light source pair corresponding to the value, the representative temperature value and the representative concentration value is specified from the selection map MS.

  The processing flow of the control unit 20D is the same as the processing flow of the control unit 20B of the second embodiment (see FIG. 6). However, in step S33, the selection unit 25D selects the selected pair using the selection map MS.

  As described above, the gas analyzer according to the fourth embodiment includes the storage unit 23D that stores the selection map MS that associates the pressure value, the temperature value, and the concentration value with the laser light source pair with the smallest measurement error. . The selection unit 25D identifies the laser light source pair corresponding to the previous temperature value T, the previous concentration value C, and the previous pressure value P from the selection map MS, and selects the identified laser light source pair as the selected pair. By storing the selection map MS in advance, it is possible to reduce the load required for the selection unit 25D to select a selected pair. As a result, the selection pair selection process can be speeded up.

<Embodiment 5>
FIG. 12 is a block diagram showing the internal configuration of the control unit 20E included in the gas analyzer according to the fifth embodiment. The gas analyzer according to the fifth embodiment is a modified example of the gas analyzer 1C according to the third embodiment, and has a control unit 20E shown in FIG. 12 instead of the control unit 20C as compared with the gas analyzer 1C. The difference is in the provision. As shown in FIG. 12, the control unit 20E includes a storage unit 23D instead of the storage unit 23B and a selection unit 25C instead of the control unit 20C of the third embodiment (see FIG. 8). The only difference is that the selection unit 25E is included. Since other points are the same as those of control unit 20C shown in FIG. 8, description thereof will not be repeated below. Further, storage unit 23D has also been described in the fourth embodiment, and therefore description will not be repeated here.

  The selection unit 25E does not perform the selection process of the selected pair in the first measurement, but performs the selection process of the selected pair in the second and subsequent measurements. The selection processing method of the selection pair in the selection unit 25E is the same as the selection processing method in the second and subsequent measurements of the selection unit 25D of the fourth embodiment.

  The processing flow of the control unit 20E is the same as the processing flow of the control unit 20C of the third embodiment (see FIG. 9). However, in step S33, the selection unit 25E selects the selected pair using the selection map MS.

  Also in the fifth embodiment, by storing the selection map MS in advance, it is possible to reduce the load required for the selection unit 25E to select a selected pair. As a result, the selection pair selection process can be speeded up.

  FIG. 13 is a diagram showing time changes between the temperature values T1 to T3 calculated by the calculation unit 24C and the actual temperature values and pressure values. As shown in FIG. 13, among the temperature values T1 to T3 calculated by the calculation unit 24C, there are some that greatly deviate from the actual temperature values.

  FIG. 14 is a diagram showing a time change between the temperature value T output from the output unit 26C and the actual temperature value and pressure value. As shown in FIG. 14, by selecting the optimum laser light source pair by the selection unit 25E, the temperature value T output from the output unit 26C is close to the implementation temperature value. Since the temperature value T is close to the actual temperature value, the density value C is also close to the actual density value according to the density calculation map. From this, it is understood that the temperature value and the concentration value of the gas to be analyzed can be accurately measured.

<Modification 1>
In the above fourth and fifth embodiments, the storage unit 23D may store only the selection map MS corresponding to one representative density value. This is because the 2f peak value is almost proportional to the concentration when the transmittance is close to 1. However, when the concentration becomes high and the transmittance becomes smaller than 1, or when the influence of the collision of molecules on the absorption spectrum cannot be ignored, the proportional relationship between the 2f peak value and the concentration is broken, and the degree is It is known that it varies depending on the wavelength. Therefore, the storage unit 23D may store a plurality of selection maps MS respectively corresponding to a plurality of expected representative concentration values in the measurement chamber 10. Further, in this case, the storage unit 23D preferably stores a plurality of concentration calculation maps and a plurality of temperature calculation maps respectively corresponding to the plurality of representative concentration values.

<Modification 2>
In the above-described first to fifth embodiments, the selecting units 25A to 25E select one selected pair from the three predetermined laser light source pairs. However, the selection units 25A to 25E may select one selected pair from the predetermined two or four or more laser light source pairs. In this case, the arithmetic units 24A and 24C calculate the temperature value and the concentration value for each of the predetermined two or four or more laser light source pairs.

For example, when the gas to be analyzed is H ₂ O, one selected pair may be selected from two predetermined laser light source pairs. In this case, one laser light source pair irradiation, for example, a laser beam of the laser light source and the center wavelength of 1343Nm (wavenumber 7444.4cm ^-1) for irradiating a laser light having a center wavelength of 1371Nm (wavenumber 7294.2cm ^-1) It is a pair with a laser light source. The other laser light source pair includes a laser light source that emits laser light having a center wavelength of 1385 nm (wavenumber 7219.6 cm ⁻¹ ) and a laser light source that emits laser light having a center wavelength of 1343 nm (wavenumber 7444.4 cm ⁻¹ ). It is a pair.

  In addition, when one selected pair is selected from two predetermined laser light source pairs, the gas analyzer may include three or more laser light sources.

  FIG. 15 is a diagram showing another example of the selection map MS. FIG. 15 shows a selection map MS used when selecting one selected pair from the two laser light source pairs Pa1 and Pa2.

<Modification 3>
In the above fourth and fifth embodiments, the selection units 25D and 25E specify the representative pressure value, the representative temperature value and the representative concentration value that are respectively closest to the previous pressure value P, the previous temperature value T and the previous concentration value C, A laser light source pair corresponding to the specified representative pressure value, representative temperature value and representative concentration value was selected. However, when the previous pressure value P, the previous temperature value T, and the previous concentration value C deviate from the representative pressure value, the representative temperature value, and the representative concentration value, respectively, the temperature value T and the concentration value C are calculated as follows. May be.

  The selection units 25D and 25E identify the selection map MS corresponding to the representative density value closest to the previous density value C. Alternatively, the selection units 25D and 25E create the selection map MS having the previous density value C as the representative density value based on the measurement error of at least one of the temperature value and the density value.

  Next, the selection units 25D and 25E specify coordinate values of four points S1 to S4 surrounding the previous temperature value T and the previous pressure value P from the selection map MS. The coordinate value of each of the four points is represented by a representative temperature value and a representative pressure value.

  FIG. 16 is a diagram showing a method of determining the weighting coefficient. As shown in FIG. 16, the selection units 25D and 25E use a rectangle having the points S1 to S4 as vertices, and two straight lines passing through the point S0 having the previous temperature value T and the previous pressure value P as coordinate values. Divide into two areas. One of the two straight lines is parallel to one of two pairs of opposing sides of a rectangle having the points S1 to S4 as vertices, and the other of the two straight lines is a two opposing sides of a rectangle having the points S1 to S4 as its apex. It is parallel to the other side of the pair. The selection units 25D and 25E determine the area of each of the four regions obtained by the division. At this time, the total value of the areas of the four regions is set to 1. The selection units 25D and 25E determine the weighting coefficient W1 for the point S1 as the area of the region farthest from the point S1. Similarly, the selection units 25D and 25E determine the weighting factors W2 to W4 of the points S2 to S4, respectively. Then, the output units 26B and 26C calculate the temperature value T and the concentration value from the temperature value and the concentration value calculated from the laser light source pair corresponding to each of the points S1 to S4 and the weighting coefficient of each of the points S1 to S4. C may be calculated.

For example, when the previous temperature value is 480K and the previous pressure value is 4.2atm, the selection units 25D and 25E select points S1 (400K, 4atm) and point S2 (500K, from the selection map MS shown in FIG. 11). 4 atm), point S3 (500 K, 5 atm), point S4 (400 K, 5 atm) are specified. In the selection map MS shown in FIG. 11, points S1 and S4 correspond to the laser light source pair Pa2, and points S2 and S3 correspond to the laser light source pair P3. Here, the temperature value and the density value calculated from the laser light source pair Pa2 are T_a2 and C_a2, respectively, and the temperature value and the density value calculated from the laser light source pair Pa3 are T_a3 and C_a3, respectively. At this time, the output units 26B and 26C are
T = T_a2 × (W1 + W4) + T_a3 × (W2 + W3)
C = C_a2 × (W1 + W4) + C_a3 × (W2 + W3)
The temperature value T and the concentration value C may be calculated in accordance with

<Modification 4>
In the first to fifth embodiments described above, the calculation units 24A and 24C use the 2f peak values corresponding to the two laser light sources included in the laser light source pair as the absorption information to determine the temperature value and the concentration value of the gas to be analyzed. It should be calculated. However, the calculation units 24A and 24C may calculate the temperature value and the concentration value of the analysis target gas by using the transmittance, the absorbance, or the value calculated from the transmittance as the absorption information instead of the 2f peak value. .

  For example, the calculation units 24A and 24C may use the transmittance of the peak of the transmittance spectrum indicated by the digital signal received from each of the light receiving units 17a to 17d as the light absorption information. Alternatively, the arithmetic units 24A and 24C may convert the transmittance spectrum indicated by the digital signal received from each of the light receiving units 17a to 17d into an absorption spectrum, and use the absorbance of the peak of the absorption spectrum as the absorption information. Alternatively, the calculation units 24A and 24C may use the transmittance spectrum indicated by the digital signal received from each of the light receiving units 17a to 17d as the absorption information. Alternatively, the calculation units 24A and 24C calculate the peak value by the method described in Japanese Patent No. 5983779 from the transmittance spectrum indicated by the digital signal received from each of the light receiving units 17a to 17d, and calculate the calculated peak value as the absorption information. You may use as.

<Modification 5>
In the first to fifth embodiments described above, the calculation units 24A and 24C calculate the temperature value and the concentration value of the gas to be analyzed based on the 2f peak values corresponding to the two laser light sources included in the laser light source pair. And However, the calculation units 24A and 24C may calculate the temperature value and the concentration value of the analysis target gas by using another method.

  As described above, the laser light sources 121a to 121d output laser light having a modulated wavelength. Therefore, the digital signals output from the light receiving units 17a to 17d fluctuate according to slight fluctuations in wavelength. The waveform obtained by plotting the intensity of the digital signal output from each of the light receiving units 17a to 17d in a graph with the wavelength on the horizontal axis and the intensity of the digital signal on the vertical axis shows the A transmittance spectrum is shown. The absorption spectrum obtained from the transmittance spectrum depends not only on the concentration of the target gas but also on the temperature and pressure of the target gas. Therefore, when the absorption spectrum with less noise components can be detected, the pressure value, temperature value, and concentration value of the gas to be analyzed can be calculated based on the detected absorption spectrum.

  Hereinafter, a modified example of calculating the pressure value, temperature value and concentration value of the gas to be analyzed from the absorption spectrum will be described.

  In this modification, the detection unit 22 detects the absorption spectra Sa to Sd based on the digital signals output from the light receiving units 17a to 17d, respectively.

  The storage units 23A, 23B, and 23D store calculation maps Ma to Md respectively corresponding to the laser light sources 121a to 121d, instead of the temperature calculation maps MT1 to MT3 and the concentration calculation maps MCa to MCd.

  The calculation map Ma is a map showing the correspondence between the information indicating the shape of the absorption spectrum of the laser light 18a by the analysis target gas and the pressure, temperature and concentration of the analysis target gas. The calculation map Mb is a map showing the correspondence between the information indicating the shape of the absorption spectrum of the laser beam 18b by the analysis target gas and the pressure, temperature and concentration of the analysis target gas. The calculation map Mc is a map showing the correspondence relationship between the information indicating the shape of the absorption spectrum of the laser light 18c by the gas to be analyzed and the pressure, temperature and concentration of the gas to be analyzed. The calculation map Md is a map showing the correspondence relationship between the information showing the shape of the absorption spectrum of the laser beam 18d by the gas to be analyzed and the pressure, temperature and concentration of the gas to be analyzed. The information indicating the shape of the absorption spectrum includes the peak value, half width, area, etc. of the absorption spectrum.

  The arithmetic units 24A and 24C respectively extract information indicating the shape of the absorption spectrum from the absorption spectra Sa to Sd. The arithmetic units 24A and 24C calculate the pressure value Pa, the temperature value Ta, and the concentration value Ca corresponding to the information extracted from the absorption spectrum Sa, using the calculation map Ma. The arithmetic units 24A and 24C calculate the pressure value Pb, the temperature value Tb, and the concentration value Cb corresponding to the information extracted from the absorption spectrum Sb, using the calculation map Mb. The calculation units 24A and 24C use the calculation map Mc to calculate the pressure value Pc, the temperature value Tc, and the concentration value Cc corresponding to the information extracted from the absorption spectrum Sc. The calculation units 24A and 24C use the calculation map Md to calculate the pressure value Pd, the temperature value Td, and the concentration value Cd corresponding to the information extracted from the absorption spectrum Sd.

  The selection units 25A to 25E select one of the laser light sources 121a to 121d as a selection light source.

  Specifically, in the case of the modifications of the first to third embodiments, the selection units 25A to 25C calculate the detection error of the information indicating the shape of the absorption spectrum Sa based on the noise component Na. Then, the selection units 25A to 25C may calculate the measurement error of the pressure value Pa, the temperature value Ta, and the concentration value Ca calculated by the calculation units 24A and 24C based on the calculated detection error.

  In the case of the modified examples of Embodiments 4 and 5, the storage unit 23D stores a plurality of representative pressure values of the analysis target gas, a plurality of representative temperature values of the analysis target gas, and a plurality of representative concentration values of the analysis target gas. And a selection map MS indicating the correspondence relationship between the selected light source and the selected light source. Then, the selection units 25D and 25E may select the selected light source corresponding to the previous pressure value P, the previous temperature value T, and the previous concentration value C indicated by the measurement result information D from the selection map MS.

  The output units 26A to 26C output the pressure value, the temperature value, and the concentration value calculated using the selected light source selected by the selection units 25A to 25E, as the measurement results (pressure value P, temperature value T, and concentration value C). do it.

  In addition, in this modification, the selection units 25A to 25E may select one selected light source from two or more predetermined laser light sources. In this case, the gas analyzer may have two or more laser light sources.

  Further, in this modification, the pressure value P is calculated from the absorption spectrum, and thus the pressure sensor 11 is not necessary.

<Modification 6>
In the first to fifth embodiments described above, the pressure value P is obtained from the pressure sensor 11. However, the pressure value P may be estimated by fitting or the like from the absorption spectrum corresponding to one laser light source of the selected pair. Furthermore, the temperature value and the concentration value may be estimated from the absorption spectrum by fitting or the like.

<Modification 7>
In the first to fifth embodiments described above, the output units 26A to 26C output the temperature value T, the concentration value C, and the pressure value P as the measurement results. However, the output units 26A to 26C may output only the temperature value T and the concentration value C as the measurement result. This is because it may be unnecessary for some users to confirm the pressure value. Note that the output units 26B and 26C update the measurement result information D based on the pressure value P measured by the pressure sensor 11 even when the pressure value P is not output as the measurement result.

<Modification 8>
A program for causing the control units 20A to 20E to execute the above-described operation may be provided. Such a program is recorded on a computer-readable recording medium such as a flexible disk attached to a computer, a CD-ROM (Compact Disk-Read Only Memory), a ROM, a RAM, and a memory card, and provided as a program product. You can also Alternatively, the program may be provided by being recorded in a recording medium such as a hard disk built in the computer. Further, the program can be provided by downloading via the network.

  The provided program product is installed and executed in a program storage unit such as a hard disk. The program product includes the program itself and a recording medium in which the program is recorded.

<Modification 9>
The first to fifth embodiments and the modified examples 1 to 8 described above may be combined appropriately. For example, the modification 5 and at least one of the modifications 1, 3, and 6 to 8 may be combined.

  The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

  1A, 1C gas analyzer, 10 measuring chamber, 11 pressure sensor, 12a-12d laser irradiation part, 13a-13d, 16a-16d optical fiber, 14a-14d, 15a-15d, 122 lens, 17a-17d light receiving part, 18a -18d laser beam, 20A-20E control part, 21 drive part, 22 detection part, 23A, 23B, 23D storage part, 24A, 24C operation part, 25A-25E selection part, 26A-26C output part, 31 temperature sensor, 32 Density sensor, 121a-121d laser light source, 123 D / A converter, 173 A / D converter, 171 condensing lens, 172 light receiving element.

Claims (14)

A gas analyzer for measuring the temperature and concentration of a gas to be analyzed,
Three or more laser light sources for irradiating laser lights of different wavelengths,
For each of the three or more laser light sources, a detection unit for detecting absorption information of the laser light emitted from the laser light source by the gas to be analyzed,
The light absorption information is any of a transmittance, an absorbance, a 2f peak value, a transmittance spectrum, and a value calculated from the transmittance spectrum,
The gas analyzer further comprises
A pressure sensor for measuring the pressure value of the gas to be analyzed,
For each of two or more laser light source pairs of the three or more laser light sources, the first absorption information detected by the detection unit for one laser light source of the laser light source pair and the detection unit for the other laser light source. A calculation for calculating a temperature value and a concentration value of the gas to be analyzed based on at least one of the second absorption information detected by S, the ratio of the first absorption information and the second absorption information, and the pressure value. Department,
A selection unit for selecting a selection pair from the two or more laser light source pairs;
An output unit that outputs the temperature value and the concentration value calculated by the calculation unit for the selected pair as a measurement result,
The selection unit calculates the calculation unit for each of the two or more laser light source pairs based on the noise component of the absorption information detected by the detection unit for each of the three or more laser light sources. A gas analyzer which calculates a measurement error of at least one of a temperature value and a concentration value, and selects a laser light source pair having the smallest calculated measurement error as the selected pair. A gas analyzer for measuring the temperature and concentration of a gas to be analyzed,
Three or more laser light sources for irradiating laser lights of different wavelengths,
For each of the three or more laser light sources, a detection unit for detecting absorption information of the laser light emitted from the laser light source by the gas to be analyzed,
The light absorption information is any of a transmittance, an absorbance, a 2f peak value, a transmittance spectrum, and a value calculated from the transmittance spectrum,
The gas analyzer further comprises
A pressure sensor for measuring the pressure value of the gas to be analyzed,
A selection unit for selecting a selection pair from two or more laser light source pairs of the three or more laser light sources;
At least one of the first light absorption information detected by the detection unit for the one laser light source and the second light absorption information detected by the detection unit for the other laser light source included in the selected pair, the first light absorption information, and the second light absorption information. A calculation unit that calculates a temperature value and a concentration value of the analysis target gas based on the ratio of the two absorption information and the pressure value,
An output unit that outputs the temperature value and the concentration value calculated by the calculation unit as a measurement result,
The selection unit, under the environment indicated by the temperature value and the concentration value indicated by the measurement result output last time by the output unit and the pressure value measured by the pressure sensor last time, of the two or more laser light source pairs. A gas analyzer which selects a laser light source pair having a minimum measurement error of at least one of the temperature value and the concentration value as the selected pair.   The gas analyzer according to claim 2, wherein the selection unit calculates the measurement error for each of the two or more laser light source pairs based on a noise component of the light absorption information detected by the detection unit. A pressure value, a temperature value, and a concentration value, and further comprising a storage unit that stores a selection map in which the measurement error is associated with the laser light source pair having the minimum,
The selection unit specifies a laser light source pair corresponding to the temperature value and the concentration value indicated by the measurement result previously output by the output unit and the pressure value previously measured by the pressure sensor from the selection map, and specifies the laser. The gas analyzer according to claim 2, wherein a light source pair is selected as the selected pair. A temperature sensor for measuring the temperature of the gas to be analyzed,
Further comprising a concentration sensor for measuring the concentration of the gas to be analyzed,
The output unit sequentially outputs the measurement results at a predetermined measurement interval,
At the time of the first measurement, the output unit outputs a temperature value measured by the temperature sensor, a concentration value measured by the concentration sensor, and a pressure value measured by the pressure sensor as a measurement result,
The gas analyzer according to claim 3 or 4, wherein the output unit outputs the temperature value and the concentration value calculated by the calculation unit as the measurement result during the second and subsequent measurements. The output unit sequentially outputs the measurement results at a predetermined measurement interval,
The gas analyzer according to claim 3 or 4, wherein the selection unit selects a predetermined laser light source pair as a selected pair during the first measurement. The selection unit identifies a plurality of laser light source pairs corresponding to the temperature value and the concentration value indicated by the measurement result previously output by the output unit and the pressure value previously measured by the pressure sensor from the selection map, and identifies the pair. Select the laser light source pair as the selected pair,
The gas according to claim 4, wherein the output unit outputs, as the measurement result, a value obtained by interpolation calculation from the temperature value and the concentration value calculated by the calculation unit for each of the plurality of laser light source pairs. Analysis equipment. A gas analyzer for measuring the temperature and concentration of a gas to be analyzed,
Two or more laser light sources for irradiating laser lights of different wavelengths,
For each of the two or more laser light sources, a detection unit that detects an absorption spectrum of the laser light emitted from the laser light sources by the gas to be analyzed,
An arithmetic unit that calculates a temperature value and a concentration value of the gas to be analyzed based on the absorption spectrum for each of the two or more laser light sources.
A selection unit for selecting a selection light source from the two or more laser light sources;
An output unit that outputs the temperature value and the concentration value calculated by the calculation unit for the selected light source as a measurement result,
The selection unit, based on the noise component of the absorption spectrum detected by the detection unit for each of the two or more laser light sources, the temperature calculated by the calculation unit for each of the two or more laser light sources. A gas analyzer which calculates a measurement error of at least one of a value and a concentration value, and selects a laser light source having the smallest calculated measurement error as the selected light source. A gas analyzer for measuring the temperature and concentration of a gas to be analyzed,
Two or more laser light sources for irradiating laser lights of different wavelengths,
For each of the two or more laser light sources, a detection unit that detects an absorption spectrum of the laser light emitted from the laser light sources by the gas to be analyzed,
A selection unit for selecting a selection light source from the two or more laser light sources;
Based on the absorption spectrum detected for the selected light source, a calculation unit for calculating the temperature value, the concentration value and the pressure value of the gas to be analyzed,
An output unit that outputs the temperature value, the concentration value, and the pressure value calculated by the calculation unit as a measurement result,
At least one of the temperature value and the concentration value under the environment indicated by the temperature value, the concentration value, and the pressure value indicated by the measurement result previously output by the output unit among the two or more laser light sources. The gas analyzer which selects the laser light source with the smallest measurement error as the selected light source.   The gas analyzer according to claim 9, wherein the selection unit calculates the measurement error for each of the two or more laser light sources based on a noise component of an absorption spectrum detected by the detection unit. A pressure value, a temperature value and a concentration value, and further comprises a storage unit for storing a selection map in which the measurement error is associated with a laser light source having a minimum,
The selection unit specifies the laser light source corresponding to the temperature value, the concentration value and the pressure value indicated by the measurement result output by the output unit last time from the selection map, and selects the specified laser light source as the selection light source, The gas analyzer according to claim 9. A temperature sensor for measuring the temperature of the gas to be analyzed,
A concentration sensor for measuring the concentration of the gas to be analyzed,
Further comprising a pressure sensor for measuring the pressure of the gas to be analyzed,
The output unit sequentially outputs the measurement results at a predetermined measurement interval,
At the time of the first measurement, the output unit outputs a temperature value measured by the temperature sensor, a concentration value measured by the concentration sensor, and a pressure value measured by the pressure sensor as a measurement result,
The gas analyzer according to claim 10 or 11, wherein the output unit outputs the temperature value, the concentration value, and the pressure value calculated by the calculation unit as measurement results during the second and subsequent measurements. The output unit sequentially outputs the measurement results at a predetermined measurement interval,
The gas analyzer according to claim 10 or 11, wherein the selection unit selects a predetermined laser light source as a selection light source during the first measurement. The selection unit specifies, from the selection map, a plurality of laser light sources corresponding to the temperature value, the concentration value, and the pressure value indicated by the measurement result previously output by the output unit, and selects the specified laser light source as the selection light source. Then
The output unit outputs, as the measurement result, a value obtained by an interpolation calculation from the temperature value, the concentration value, and the pressure value calculated by the calculation unit for each of the plurality of laser light sources. Gas analyzer.

Images