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JP6148836B2 - Gas concentration measuring device - Google Patents

Gas concentration measuring device Download PDF

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JP6148836B2
JP6148836B2 JP2012201026A JP2012201026A JP6148836B2 JP 6148836 B2 JP6148836 B2 JP 6148836B2 JP 2012201026 A JP2012201026 A JP 2012201026A JP 2012201026 A JP2012201026 A JP 2012201026A JP 6148836 B2 JP6148836 B2 JP 6148836B2
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optical path
path length
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column density
concentration
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JP2014055858A (en
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啓一 曽根
啓一 曽根
博之 玉本
博之 玉本
伊藤 一博
一博 伊藤
健 安部
健 安部
敏之 鈴木
敏之 鈴木
毅 原
毅 原
教明 山崎
教明 山崎
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Anritsu Corp
Tokyo Metropolitan Sewerage Service Corp
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Tokyo Metropolitan Sewerage Service Corp
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Description

本発明は、ガス濃度測定装置に関する。特に、被測定ガスが有毒ガスまたは可燃性ガス等危険性を伴うガスであっても、漏洩または発生箇所から離れて安全に濃度測定が可能なガス濃度測定装置に関する。   The present invention relates to a gas concentration measuring apparatus. In particular, the present invention relates to a gas concentration measuring apparatus capable of safely measuring a concentration away from a leaked or generated place even if a gas to be measured is a gas with danger such as a toxic gas or a flammable gas.

たとえば、特許文献1には、メタン等ガス分子の赤外光吸収特性を利用して、メタン、二酸化炭素等のガスを検出するガス検出装置が開示されている。当該ガス検出装置では、検出光として赤外レーザ光を用い、被検出ガスを通過した検出光の乱反射光の受光信号を2f同期検波することにより、被検出ガスの濃度が低い場合であっても被検出ガスの存在を高感度に検出することが可能になっている。   For example, Patent Document 1 discloses a gas detection device that detects a gas such as methane or carbon dioxide by using infrared light absorption characteristics of gas molecules such as methane. In the gas detection device, even when the concentration of the detected gas is low by using infrared laser light as detection light and performing 2f synchronous detection of the light reception signal of the irregularly reflected light of the detected light that has passed through the detected gas, The presence of the gas to be detected can be detected with high sensitivity.

特開2001−235420号公報JP 2001-235420 A

しかし、従来のガス検出装置により得られる測定量は、被検出ガスのコラム密度、すなわち被検出ガスの濃度に被検出ガスの厚みを乗じた量であり、当該ガス検出装置の測定により、被検出ガスの濃度を直ちに知ることはできない。また、当該ガス検出装置による被検出ガスの検出で判明することは、検出光の光路の何処かに被検出ガスが存在することに留まり、測定量であるコラム密度は、検出光が通過する経路における被検出ガスの厚みに応じて変化するので、局所的な被検出ガスの濃度を知ることはできない。さらに、測定した結果をビジュアルに表現して、ガス漏洩等の実態の視認性を高める要請もある。   However, the measurement amount obtained by the conventional gas detection device is the column density of the gas to be detected, that is, the concentration of the gas to be detected multiplied by the thickness of the gas to be detected. The concentration of gas cannot be known immediately. Further, what is found by detection of the gas to be detected by the gas detection device is that the gas to be detected exists somewhere in the optical path of the detection light, and the column density as a measurement amount is a path through which the detection light passes. Therefore, the local concentration of the gas to be detected cannot be known. In addition, there is also a demand to improve the visibility of actual conditions such as gas leakage by visually expressing the measurement results.

本発明の目的は、空間的に分布する被測定ガスの濃度を平均としてまたは局所的に測定することができるガス濃度測定装置を提供することにある。また、本発明の目的は、測定結果の視認性を高めることにある。   An object of the present invention is to provide a gas concentration measuring apparatus capable of measuring the concentration of a gas to be measured spatially distributed as an average or locally. Another object of the present invention is to improve the visibility of measurement results.

上記課題を解決するために、本発明の第1の態様においては、検出光を放射する検出光放射部と、前記検出光が物体に照射された場合に前記物体から反射される反射光を受光する受光部と、前記受光部が受光した前記反射光から、被検出ガスのコラム密度を測定するコラム密度測定部と、前記検出光放射部から前記物体に至る前記検出光の光路長を測定する光路長測定部と、前記コラム密度および前記光路長に基づき、前記被検出ガスの濃度を計算する濃度計算部と、を有するガス濃度測定装置を提供する。   In order to solve the above problems, in the first aspect of the present invention, a detection light emitting unit that emits detection light and reflected light that is reflected from the object when the detection light is irradiated to the object are received. A light receiving unit that measures the column density of the gas to be detected from the reflected light received by the light receiving unit, and an optical path length of the detection light from the detection light emitting unit to the object. There is provided a gas concentration measuring device comprising: an optical path length measuring unit; and a concentration calculating unit that calculates the concentration of the detected gas based on the column density and the optical path length.

前記濃度計算部として、前記コラム密度を前記光路長で割ることにより、前記検出光の光路に沿った前記被検出ガスの平均濃度を計算するものを例示することができる。あるいは、前記コラム密度および前記光路長を一時的に記録する一時記録部をさらに有してもよく、前記濃度計算部として、前記コラム密度測定部により測定された現在のコラム密度と前記一時記録部から読み出された前のコラム密度との差であるコラム密度差、および、前記光路長測定部により測定された現在の光路長と前記一時記録部から読み出された前の光路長との差である光路長差、を計算し、前記コラム密度差を前記光路長差で割ることにより、前記光路長差を生じた前記光路の変更領域における前記被検出ガスの濃度を計算するものを例示することができる。   Examples of the concentration calculation unit include one that calculates the average concentration of the gas to be detected along the optical path of the detection light by dividing the column density by the optical path length. Alternatively, it may further include a temporary recording unit that temporarily records the column density and the optical path length, and as the density calculation unit, the current column density measured by the column density measurement unit and the temporary recording unit The difference between the column density difference that is the difference from the previous column density read from the optical path length, and the difference between the current optical path length measured by the optical path length measurement unit and the previous optical path length read from the temporary recording unit And calculating the concentration of the detected gas in the change region of the optical path that caused the optical path length difference by calculating the optical path length difference, and dividing the column density difference by the optical path length difference. be able to.

所定の照射領域において前記検出光の放射方向を調整する放射方向調整部をさらに有してもよく、この場合、前記放射方向調整部により前記検出光の放射方向が第1方向に調整されている第1状態において、前記コラム密度測定部および前記光路長測定部のそれぞれが前記コラム密度および前記光路長をそれぞれ測定し、測定された前記コラム密度および前記光路長を前記一時記録部に記録し、前記放射方向調整部により前記検出光の放射方向が第1方向とは異なる第2方向に調整されている第2状態において、前記コラム密度測定部および前記光路長測定部のそれぞれが前記コラム密度および前記光路長をそれぞれ測定し、測定された前記コラム密度および前記光路長と、前記一時記録部から読み出された前記コラム密度および前記光路長とから、前記濃度計算部が、前記コラム密度差および前記光路長差を計算し、さらに前記被検出ガスの濃度を計算することができる。   A radiation direction adjusting unit that adjusts the radiation direction of the detection light in a predetermined irradiation region may be further included. In this case, the radiation direction of the detection light is adjusted to the first direction by the radiation direction adjustment unit. In the first state, each of the column density measuring unit and the optical path length measuring unit measures the column density and the optical path length, respectively, and records the measured column density and the optical path length in the temporary recording unit, In the second state in which the radiation direction of the detection light is adjusted in the second direction different from the first direction by the radiation direction adjustment unit, each of the column density measurement unit and the optical path length measurement unit has the column density and The optical path length is measured, the measured column density and optical path length, and the column density and optical path length read from the temporary recording unit. From the density calculation section, the column density difference and calculates the optical path length difference, it is possible to further calculate the concentration of the gas to be detected.

前記濃度計算部が計算した前記被検出ガスの濃度を表示する表示部をさらに有し、前記所定の照射領域が、一次元または二次元に配列された複数の副領域に区分されてもよく、この場合、前記複数の副領域のそれぞれにおいて、前記第1状態における前記コラム密度および前記光路長の記録と前記第2状態における前記被検出ガスの濃度の計算とが行われ、前記複数の副領域のそれぞれに対応した前記表示部の表示領域に、前記複数の副領域のそれぞれに対応した前記被検出ガスの濃度を表示してもよい。   The display may further include a display unit that displays the concentration of the detected gas calculated by the concentration calculation unit, and the predetermined irradiation region may be divided into a plurality of sub-regions arranged one-dimensionally or two-dimensionally, In this case, in each of the plurality of sub-regions, the recording of the column density and the optical path length in the first state and the calculation of the concentration of the gas to be detected in the second state are performed. The concentration of the detected gas corresponding to each of the plurality of sub-regions may be displayed on the display region of the display unit corresponding to each of the sub-regions.

実施の形態1のガス濃度測定装置100を示した構成図である。1 is a configuration diagram showing a gas concentration measuring apparatus 100 according to Embodiment 1. FIG. 実施の形態2のガス濃度測定装置200を示した構成図である。FIG. 5 is a configuration diagram showing a gas concentration measuring apparatus 200 according to a second embodiment. ガス濃度測定装置200の測定原理を説明するための概念図である。4 is a conceptual diagram for explaining a measurement principle of a gas concentration measuring apparatus 200. FIG. ガス濃度測定装置200の使用態様の一例を示した概念図である。It is the conceptual diagram which showed an example of the usage condition of the gas concentration measuring apparatus 200.

(実施形態1)
図1は、ガス濃度測定装置100を示した構成図である。ガス濃度測定装置100は、検出光放射部102、受光部104、コラム密度測定部106、光路長測定部108、測距用光源110、濃度計算部120、表示部130および制御部140を有する。ガス濃度測定装置100は、検出光放射部102から検出光112を放射し、被検出ガス150を通過した検出光112が物体160に反射されて生じた反射光116を受光し、当該反射光116からから被検出ガス150のコラム密度を測定する。また、ガス濃度測定装置100は、測距用光源110から測距光114を放射し、物体160までの距離(光路長)を測定する。さらに、ガス濃度測定装置100は、コラム密度と光路長から被検出ガス150の濃度を計算する。なお、検出光112と測距光114は、たとえばミラー118からなる光学系により光軸が一致される。
(Embodiment 1)
FIG. 1 is a configuration diagram showing a gas concentration measuring apparatus 100. The gas concentration measuring apparatus 100 includes a detection light emitting unit 102, a light receiving unit 104, a column density measuring unit 106, an optical path length measuring unit 108, a distance measuring light source 110, a concentration calculating unit 120, a display unit 130, and a control unit 140. The gas concentration measurement apparatus 100 radiates the detection light 112 from the detection light emitting unit 102, receives the reflected light 116 that is generated when the detection light 112 that has passed through the detection target gas 150 is reflected by the object 160, and receives the reflected light 116. To measure the column density of the gas 150 to be detected. Further, the gas concentration measuring apparatus 100 emits distance measuring light 114 from the distance measuring light source 110 and measures the distance (optical path length) to the object 160. Further, the gas concentration measuring apparatus 100 calculates the concentration of the detected gas 150 from the column density and the optical path length. Note that the optical axes of the detection light 112 and the distance measurement light 114 are matched by an optical system including a mirror 118, for example.

検出光放射部102は、検出光112を放射する。検出光112は、コヒーレント光またはインコヒーレント光の何れでもよいが、コラム密度の測定に同期検波を用いる場合、検出光112はコヒーレント光であることが好ましい。検出光112は、被検出ガス150に吸収される必要があり、被検出ガス150に応じて適切な波長を選択する。たとえば、被検出ガス150がメタンである場合、検出光112として発振波長が1.65μm帯の赤外レーザ光を用いることができる。被検出ガス150が硫化水素である場合、検出光112として発振波長が1.91μm帯の赤外レーザ光を用いることができる。なお、コラム密度の測定に同期検波を用いる場合、検出光112の波長は、被検出ガス150の吸収帯中心波長に調整されることが望ましい。検出光放射部102に半導体レーザ発振器を用いる場合、被検出ガス150を封入した標準セルを準備し、当該標準セルでの光吸収を参照して、検出光112の発振波長が被検出ガス150の吸収帯中心波長に一致するよう半導体レーザ発振器の動作温度等を調整することができる。   The detection light emitting unit 102 emits detection light 112. The detection light 112 may be either coherent light or incoherent light. However, when synchronous detection is used for measuring the column density, the detection light 112 is preferably coherent light. The detection light 112 needs to be absorbed by the gas 150 to be detected, and an appropriate wavelength is selected according to the gas 150 to be detected. For example, when the detection gas 150 is methane, an infrared laser beam having an oscillation wavelength of 1.65 μm band can be used as the detection light 112. When the gas to be detected 150 is hydrogen sulfide, an infrared laser beam having an oscillation wavelength of 1.91 μm band can be used as the detection light 112. When synchronous detection is used for measuring the column density, it is desirable that the wavelength of the detection light 112 is adjusted to the absorption band center wavelength of the gas 150 to be detected. When a semiconductor laser oscillator is used for the detection light emitting unit 102, a standard cell in which the detection gas 150 is sealed is prepared, and the oscillation wavelength of the detection light 112 is set to be that of the detection gas 150 by referring to light absorption in the standard cell. The operating temperature and the like of the semiconductor laser oscillator can be adjusted to match the absorption band center wavelength.

受光部104は、検出光112が物体160に照射された場合に物体160から反射される反射光116を受光する。受光部104として、たとえばフォトダイオード、フォトマルチプライヤー等の光電変換素子とその駆動検出回路を例示することができる。この場合、受光部104は、受光した反射光116の強度に応じた電気信号を発生する。受光部104には、たとえばバンドパスフィルタ等の光学フィルタ、スリット、分光機構等の適切な光学系を備えてもよい。   The light receiving unit 104 receives reflected light 116 reflected from the object 160 when the detection light 112 is irradiated onto the object 160. Examples of the light receiving unit 104 include a photoelectric conversion element such as a photodiode and a photomultiplier and a drive detection circuit thereof. In this case, the light receiving unit 104 generates an electrical signal corresponding to the intensity of the received reflected light 116. The light receiving unit 104 may include an appropriate optical system such as an optical filter such as a band pass filter, a slit, or a spectroscopic mechanism.

コラム密度測定部106は、受光部104が受光した反射光116から、被検出ガス150のコラム密度を測定する。受光部104として光電変換素子を用いる場合、コラム密度測定部106は、受光部104が出力する信号を処理し、検出光112の被検出ガス150による光吸収量を計測する。   The column density measuring unit 106 measures the column density of the gas 150 to be detected from the reflected light 116 received by the light receiving unit 104. When a photoelectric conversion element is used as the light receiving unit 104, the column density measuring unit 106 processes a signal output from the light receiving unit 104 and measures the amount of light absorbed by the detection gas 150 of the detection light 112.

たとえば、同期検波を用いて光吸収量を計測する場合、以下のような原理を用いる。すなわち、検出光112としてレーザ光を用い、当該レーザ光の発振波長が被検出ガス150の吸収帯中心波長に一致する場合、被検出ガス150を透過した光には、被検出ガス150の光吸収による2倍波が含まれるようになる。一方、検出光112が物体160によって散乱され反射光116として検出される割合は、被検出ガス150の有無によって左右されないので、受光した反射光116に含まれる基本波の強度に対する2倍波の強度を測定すれば、測定値は光路に沿った光吸収量を表すことになる。このような測定法を同期検波と称する。光吸収量は光路に存在する被検出ガス150の分子数に比例するから、光路長に依存した被検出ガス150の濃度(コラム密度)に換算することができる。このようにしてコラム密度を測定することができる。   For example, when measuring the amount of light absorption using synchronous detection, the following principle is used. That is, when laser light is used as the detection light 112 and the oscillation wavelength of the laser light coincides with the absorption band center wavelength of the gas to be detected 150, the light that has passed through the gas to be detected 150 is absorbed by the light to be detected 150. 2nd harmonic wave is included. On the other hand, the rate at which the detection light 112 is scattered by the object 160 and detected as the reflected light 116 does not depend on the presence or absence of the gas to be detected 150, so the intensity of the double wave with respect to the intensity of the fundamental wave contained in the received reflected light 116 Is measured, the measured value represents the amount of light absorption along the optical path. Such a measurement method is called synchronous detection. Since the amount of light absorption is proportional to the number of molecules of the gas to be detected 150 existing in the optical path, it can be converted into the concentration (column density) of the gas to be detected 150 depending on the optical path length. In this way, the column density can be measured.

コラム密度測定部106は、同期検波による測定法に限らず、他の測定法を採用することもできる。たとえば、検出光112に、被検出ガス150に吸収される第1波長の光と被検出ガス150に吸収されない第2波長の光を含め、反射光116に含まれる第2波長の光の強度に対する第1波長の光の強度を測定して被検出ガス150による光吸収量を測定することもできる。   The column density measurement unit 106 is not limited to the measurement method based on the synchronous detection, and may employ other measurement methods. For example, the detection light 112 includes the light of the first wavelength absorbed by the gas to be detected 150 and the light of the second wavelength not absorbed by the gas to be detected 150, with respect to the intensity of the light of the second wavelength included in the reflected light 116. It is also possible to measure the amount of light absorbed by the detected gas 150 by measuring the intensity of the first wavelength light.

光路長測定部108は、検出光放射部102から物体160に至る検出光112の光路長を測定する。光路長測定部108として、光学式距離計、超音波式距離計、光波(レーザ光線、電波)測距儀等を例示することができる。光路長測定部108としてレーザ測距儀を用いる場合、測距用光源110として、たとえば半導体レーザを挙げることができる。測距用光源110から放射された測距光114の光軸と検出光112の光軸は、ミラー118からなる光学系により一致されているので、測距光114による距離測定によって検出光112の光路長を正確に測定することができる。測距用光源110と検出光放射部102とが同様のレーザ光を放射する場合、両者を兼用することも可能である。   The optical path length measurement unit 108 measures the optical path length of the detection light 112 from the detection light emission unit 102 to the object 160. Examples of the optical path length measurement unit 108 include an optical distance meter, an ultrasonic distance meter, and a light wave (laser beam, radio wave) range finder. When a laser distance measuring instrument is used as the optical path length measuring unit 108, the distance measuring light source 110 may be a semiconductor laser, for example. Since the optical axis of the distance measuring light 114 emitted from the distance measuring light source 110 and the optical axis of the detection light 112 are matched by the optical system including the mirror 118, the distance of the detection light 112 is measured by the distance measurement using the distance measuring light 114. The optical path length can be accurately measured. When the distance measuring light source 110 and the detection light emitting unit 102 emit the same laser light, both can be used together.

濃度計算部120は、コラム密度測定部106が測定したコラム密度および光路長測定部108が測定した光路長に基づき、被検出ガス150の濃度を計算する。本実施形態1のガス濃度測定装置100の濃度計算部120では、コラム密度を光路長で割ることにより、検出光112の光路に沿った被検出ガス150の平均濃度を計算することができる。   The concentration calculation unit 120 calculates the concentration of the gas 150 to be detected based on the column density measured by the column density measurement unit 106 and the optical path length measured by the optical path length measurement unit 108. In the concentration calculation unit 120 of the gas concentration measurement apparatus 100 according to the first embodiment, the average concentration of the gas 150 to be detected along the optical path of the detection light 112 can be calculated by dividing the column density by the optical path length.

表示部130は、濃度計算部120が計算した被検出ガス150の濃度を表示する。本実施形態1のガス濃度測定装置100における表示部130は、濃度計算部120が計算した被検出ガス150の平均濃度を表示する。制御部140は、ガス濃度測定装置100に含まれる各部の制御を実行する。   The display unit 130 displays the concentration of the detected gas 150 calculated by the concentration calculation unit 120. The display unit 130 in the gas concentration measurement apparatus 100 according to the first embodiment displays the average concentration of the detection target gas 150 calculated by the concentration calculation unit 120. The control unit 140 performs control of each unit included in the gas concentration measurement apparatus 100.

ガス濃度測定装置100によれば、コラム密度測定部106によるコラム密度の測定と共に、光路長測定部108により光路長を測定する。このため、コラム密度と光路長とから、光の通過距離に依存しない被検出ガス150の濃度を測定することができる。従来の測定では、コラム密度の測定に留まり、測定値の単位にはppm・mのように長さの次元が含まれていたが、本実施形態1のガス濃度測定装置100による測定単位には、長さの次元は含まれず、ガス濃度測定装置100の測定値は、ppmのような密度の単位のみで表されることになる。   According to the gas concentration measuring apparatus 100, the optical path length is measured by the optical path length measuring unit 108 along with the measurement of the column density by the column density measuring unit 106. Therefore, the concentration of the gas 150 to be detected can be measured from the column density and the optical path length without depending on the light passing distance. In the conventional measurement, the measurement is limited to the measurement of the column density, and the unit of the measurement value includes a dimension of length such as ppm · m. However, the measurement unit by the gas concentration measurement apparatus 100 of the first embodiment includes The dimension of the length is not included, and the measurement value of the gas concentration measuring apparatus 100 is represented only by the density unit such as ppm.

なお、ガス濃度測定装置100において、測距光114に可視レーザ光を用いることができる。この場合、可視レーザ光が照射されている場所が測定箇所であることが目視でき、測距光114を、測定箇所を示すガイド光に用いることができる。   In the gas concentration measuring apparatus 100, visible laser light can be used as the distance measuring light 114. In this case, it can be visually observed that the place irradiated with the visible laser beam is the measurement place, and the distance measuring light 114 can be used as the guide light indicating the measurement place.

(実施形態2)
図2は、ガス濃度測定装置200を示した構成図である。ガス濃度測定装置200は、実施形態1で説明したガス濃度測定装置100の構成に加え、一時記録部210および放射方向調整部230を有する。実施形態1で説明した、検出光放射部102、受光部104、コラム密度測定部106、光路長測定部108および測距用光源110については、ほぼ同様であり説明を省略する。ガス濃度測定装置200は、実施形態1と同様にコラム密度および光路長を測定するが、測定したコラム密度および光路長は、一旦、一時記録部210に記録し、放射方向調整部230により光路を少し変更して測定したコラム密度および光路長との差から被検出ガス150の濃度を計算する。なお、検出光112と測距光114が、たとえばミラー118からなる光学系により光軸が一致されることは実施形態1と同様であるが、本実施形態2のガス濃度測定装置200では、ガイド光放射部220を備える。ガイド光放射部220が放射するガイド光222の放射方向は、たとえばミラー224からなる光学系により、検出光112および測距光114の放射方向と概略一致するように調整される。
(Embodiment 2)
FIG. 2 is a configuration diagram showing the gas concentration measuring apparatus 200. The gas concentration measuring apparatus 200 includes a temporary recording unit 210 and a radial direction adjusting unit 230 in addition to the configuration of the gas concentration measuring apparatus 100 described in the first embodiment. The detection light emitting unit 102, the light receiving unit 104, the column density measuring unit 106, the optical path length measuring unit 108, and the distance measuring light source 110 described in the first embodiment are substantially the same and will not be described. The gas concentration measuring apparatus 200 measures the column density and the optical path length in the same manner as in the first embodiment. The measured column density and the optical path length are temporarily recorded in the temporary recording unit 210, and the optical direction is adjusted by the radiation direction adjusting unit 230. The concentration of the gas to be detected 150 is calculated from the difference between the column density and the optical path length measured with slight changes. The optical axis of the detection light 112 and the distance measurement light 114 are matched with each other by, for example, an optical system including a mirror 118 as in the first embodiment. However, in the gas concentration measurement apparatus 200 of the second embodiment, a guide is used. A light emitting unit 220 is provided. The radiation direction of the guide light 222 emitted from the guide light radiation unit 220 is adjusted by the optical system including the mirror 224, for example, so as to substantially coincide with the radiation directions of the detection light 112 and the ranging light 114.

一時記録部210は、コラム密度および光路長を一時的に記録する。一時記録部210として、レジスタ等の半導体メモリを例示することができる。制御部140がCPU等のマイクロプロセッサで構成される場合、一時記録部210は、制御部140の内部に含まれてもよい。   The temporary recording unit 210 temporarily records the column density and the optical path length. An example of the temporary recording unit 210 is a semiconductor memory such as a register. When the control unit 140 is configured by a microprocessor such as a CPU, the temporary recording unit 210 may be included in the control unit 140.

放射方向調整部230は、ガイド光222の照射位置を中心とした所定の照射領域において検出光112および測距光114の放射方向を調整するものである。検出光112と測距光114の放射方向は別々に調整されてもよい。放射方向調整部230として、ポリゴンミラー等の光学系を例示することができる。   The radiation direction adjusting unit 230 adjusts the radiation directions of the detection light 112 and the distance measuring light 114 in a predetermined irradiation region centered on the irradiation position of the guide light 222. The radiation directions of the detection light 112 and the distance measurement light 114 may be adjusted separately. An example of the radiation direction adjusting unit 230 is an optical system such as a polygon mirror.

ガイド光放射部220はガイド光222を放射する。ガイド光222は、測定領域を指し示す光であり、たとえば可視レーザ光を例示することができる。制御部140は、濃度計算部120、一時記録部210、放射方向調整部230等ガス濃度測定装置200に含まれる各部の制御を実行する。   The guide light emitting unit 220 emits guide light 222. The guide light 222 is light indicating a measurement region, and for example, visible laser light can be exemplified. The control unit 140 executes control of each unit included in the gas concentration measurement device 200 such as the concentration calculation unit 120, the temporary recording unit 210, and the radiation direction adjustment unit 230.

本実施形態2のガス濃度測定装置200における濃度計算部120は、コラム密度測定部106により測定された現在のコラム密度と一時記録部210から読み出された前のコラム密度との差であるコラム密度差を計算する。また、光路長測定部108により測定された現在の光路長と一時記録部210から読み出された前の光路長との差である光路長差を計算する。さらに、コラム密度差を光路長差で割ることにより光路長差を生じた光路の変更領域における被検出ガス150の濃度を計算する。   The concentration calculation unit 120 in the gas concentration measurement apparatus 200 according to the second embodiment is a column that is a difference between the current column density measured by the column density measurement unit 106 and the previous column density read from the temporary recording unit 210. Calculate the density difference. Further, an optical path length difference which is a difference between the current optical path length measured by the optical path length measuring unit 108 and the previous optical path length read from the temporary recording unit 210 is calculated. Further, by dividing the column density difference by the optical path length difference, the concentration of the gas 150 to be detected in the optical path change region in which the optical path length difference has occurred is calculated.

つまり、放射方向調整部230により検出光112の放射方向が第1方向に調整されている第1状態において、コラム密度測定部106および光路長測定部108のそれぞれがコラム密度および光路長をそれぞれ測定し、測定されたコラム密度および光路長を一時記録部210に記録し、放射方向調整部230により検出光112の放射方向が第1方向とは異なる第2方向に調整されている第2状態において、コラム密度測定部106および光路長測定部108のそれぞれがコラム密度および光路長をそれぞれ測定し、測定されたコラム密度および光路長と、一時記録部210から読み出されたコラム密度および光路長とから、濃度計算部120が被検出ガス150の濃度を計算する。   That is, in the first state where the radiation direction of the detection light 112 is adjusted to the first direction by the radiation direction adjusting unit 230, the column density measuring unit 106 and the optical path length measuring unit 108 respectively measure the column density and the optical path length. In the second state, the measured column density and the optical path length are recorded in the temporary recording unit 210, and the radiation direction adjusting unit 230 adjusts the radiation direction of the detection light 112 in the second direction different from the first direction. The column density measuring unit 106 and the optical path length measuring unit 108 respectively measure the column density and the optical path length, and the measured column density and optical path length, and the column density and the optical path length read from the temporary recording unit 210, respectively. From the above, the concentration calculation unit 120 calculates the concentration of the gas 150 to be detected.

図3は、ガス濃度測定装置200の測定原理を説明するための概念図である。まず、検出光112および測距光114の照射位置を、図3における上側の矢印Aで示す位置としてコラム密度および経路長を測定する。この時のコラム密度をV、経路長をLとして一時記録部210に記録する。次に、検出光112および測距光114の照射位置を下側の矢印Bで示す位置に変更してコラム密度および経路長を測定する。この時のコラム密度をV+ΔV、経路長をL+ΔLとする。経路長差ΔLを生じた光経路に係る部分のコラム密度は、コラム密度差ΔVであり、コラム密度差ΔVを経路長差ΔLで割った値(ΔV/ΔL)は、光路長差を生じた光路の変更領域における被検出ガス150の濃度である。   FIG. 3 is a conceptual diagram for explaining the measurement principle of the gas concentration measuring apparatus 200. First, the column density and the path length are measured with the irradiation position of the detection light 112 and the distance measurement light 114 as the position indicated by the upper arrow A in FIG. At this time, the column density is V and the path length is L, and is recorded in the temporary recording unit 210. Next, the irradiation position of the detection light 112 and the distance measurement light 114 is changed to the position indicated by the arrow B on the lower side, and the column density and the path length are measured. The column density at this time is V + ΔV, and the path length is L + ΔL. The column density of the portion related to the optical path that caused the path length difference ΔL is the column density difference ΔV, and the value obtained by dividing the column density difference ΔV by the path length difference ΔL (ΔV / ΔL) resulted in the optical path length difference. This is the concentration of the gas to be detected 150 in the optical path change region.

ガス濃度測定装置200によれば、光路を少し変更して光路長差を生じさせ、当該光路長差を生じた変更領域における被検出ガス150の濃度が計測できるため、局所的なガス濃度を測定することができる。たとえばガス漏れ等を発生している場所は、局所的に高濃度になっていると思われ、このような場所におけるガス濃度を知ることができる。漏洩ガスが可燃性、毒性等を有する危険ガスである場合、離れた場所からガス濃度を測定することができ、安全上のメリットも大きい。   According to the gas concentration measuring apparatus 200, the optical path is slightly changed to generate an optical path length difference, and the concentration of the detected gas 150 in the changed region where the optical path length difference is generated can be measured. can do. For example, a place where a gas leak or the like is generated is considered to be locally high in concentration, and the gas concentration at such a place can be known. When the leaked gas is a dangerous gas having flammability, toxicity, etc., the gas concentration can be measured from a remote location, and the safety merit is great.

図4は、ガス濃度測定装置200の使用態様の一例を示した概念図である。ガス濃度測定装置200では、測定領域である照射領域240が、二次元に配列された複数の副領域242に区分されており、複数の副領域242のそれぞれにおいて、濃度の計算が行われる。すなわち、副領域242のそれぞれにおいて、第1状態におけるコラム密度および光路長の記録と第2状態における被検出ガス150の濃度の計算とが行われる。さらに、ガス濃度測定装置200では、複数の副領域242のそれぞれに対応した表示部130の表示領域に、複数の副領域242のそれぞれに対応した被検出ガス150の濃度を表示する。濃度の表示方式として、たとえば図4に示すような、濃度に応じた濃淡(グレースケール)を採用することができる。これにより、測定結果の視認性を高めることができる。なお、濃度の表示方式は、色による表示であってもよい。照射領域240は、一次元に区分されてもよい。   FIG. 4 is a conceptual diagram showing an example of how the gas concentration measuring apparatus 200 is used. In the gas concentration measuring apparatus 200, the irradiation region 240 as a measurement region is divided into a plurality of sub-regions 242 arranged in two dimensions, and the concentration is calculated in each of the plurality of sub-regions 242. That is, in each of the subregions 242, the recording of the column density and the optical path length in the first state and the calculation of the concentration of the detected gas 150 in the second state are performed. Further, in the gas concentration measuring apparatus 200, the concentration of the detection gas 150 corresponding to each of the plurality of sub-regions 242 is displayed on the display region of the display unit 130 corresponding to each of the plurality of sub-regions 242. As a density display method, for example, a shade (gray scale) corresponding to the density as shown in FIG. 4 can be adopted. Thereby, the visibility of a measurement result can be improved. The density display method may be a color display. The irradiation area 240 may be divided into one dimension.

以上、本発明を実施の形態を用いて説明したが、本発明の技術的範囲は上記実施の形態に記載の範囲には限定されない。上記実施の形態に、多様な変更または改良を加えることが可能であることが当業者に明らかである。その様な変更または改良を加えた形態も本発明の技術的範囲に含まれ得ることが、特許請求の範囲の記載から明らかである。   As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

100…ガス濃度測定装置、102…検出光放射部、104…受光部、106…コラム密度測定部、108…光路長測定部、110…測距用光源、112…検出光、114…測距光、116…反射光、118…ミラー、120…濃度計算部、130…表示部、140…制御部、150…被検出ガス、160…物体、200…ガス濃度測定装置、210…一時記録部、220…ガイド光放射部、222…ガイド光、224…ミラー、230…放射方向調整部、240…照射領域、242…副領域。   DESCRIPTION OF SYMBOLS 100 ... Gas concentration measuring device, 102 ... Detection light emission part, 104 ... Light receiving part, 106 ... Column density measurement part, 108 ... Optical path length measurement part, 110 ... Light source for distance measurement, 112 ... Detection light, 114 ... Distance measurement light , 116 ... reflected light, 118 ... mirror, 120 ... concentration calculation section, 130 ... display section, 140 ... control section, 150 ... detected gas, 160 ... object, 200 ... gas concentration measuring device, 210 ... temporary recording section, 220 ... guide light radiation part, 222 ... guide light, 224 ... mirror, 230 ... radiation direction adjustment part, 240 ... irradiation area, 242 ... sub area.

Claims (3)

検出光を放射する検出光放射部と、
前記検出光が物体に照射された場合に前記物体から反射される反射光を受光する受光部と、
前記受光部が受光した前記反射光から、被検出ガスのコラム密度を測定するコラム密度測定部と、
前記検出光放射部から前記物体に至る前記検出光の光路長を測定する光路長測定部と、
前記コラム密度および前記光路長に基づき、前記被検出ガスの濃度を計算する濃度計算部と、
前記コラム密度および前記光路長を一時的に記録する一時記録部と、
所定の照射領域において前記検出光の放射方向を調整する放射方向調整部と、を有し、
前記濃度計算部が、前記コラム密度測定部により測定された現在のコラム密度と前記一時記録部から読み出された前のコラム密度との差であるコラム密度差、および、前記光路長測定部により測定された現在の光路長と前記一時記録部から読み出された前の光路長との差である光路長差、を計算し、前記コラム密度差を前記光路長差で割ることにより、前記光路長差を生じた前記光路の変更領域における前記被検出ガスの濃度を計算し、
前記放射方向調整部により前記検出光の放射方向が第1方向に調整されている第1状態において、前記コラム密度測定部および前記光路長測定部のそれぞれが前記コラム密度および前記光路長をそれぞれ測定し、測定された前記コラム密度および前記光路長を前記一時記録部に記録し、
前記放射方向調整部により前記検出光の放射方向が第1方向とは異なる第2方向に調整されている第2状態において、前記コラム密度測定部および前記光路長測定部のそれぞれが前記コラム密度および前記光路長をそれぞれ測定し、測定された前記コラム密度および前記光路長と、前記一時記録部から読み出された前記コラム密度および前記光路長とから、前記濃度計算部が、前記コラム密度差および前記光路長差を計算し、さらに前記被検出ガスの濃度を計算する
ガス濃度測定装置。
A detection light emitting section for emitting detection light;
A light receiving unit that receives reflected light reflected from the object when the object is irradiated with the detection light;
From the reflected light received by the light receiving unit, a column density measuring unit that measures the column density of the gas to be detected;
An optical path length measurement unit for measuring an optical path length of the detection light from the detection light emitting unit to the object;
Based on the column density and the optical path length, a concentration calculator that calculates the concentration of the detected gas;
A temporary recording unit for temporarily recording the column density and the optical path length;
A radiation direction adjusting unit that adjusts the radiation direction of the detection light in a predetermined irradiation region,
The density calculation unit is configured to provide a column density difference that is a difference between a current column density measured by the column density measurement unit and a previous column density read from the temporary recording unit, and an optical path length measurement unit. Calculating the optical path length difference, which is the difference between the measured current optical path length and the previous optical path length read from the temporary recording unit, and dividing the column density difference by the optical path length difference; Calculate the concentration of the gas to be detected in the changed region of the optical path that caused a length difference,
In the first state in which the radiation direction of the detection light is adjusted to the first direction by the radiation direction adjustment unit, the column density measurement unit and the optical path length measurement unit respectively measure the column density and the optical path length. And recording the measured column density and the optical path length in the temporary recording unit,
In the second state in which the radiation direction of the detection light is adjusted in the second direction different from the first direction by the radiation direction adjustment unit, each of the column density measurement unit and the optical path length measurement unit has the column density and Each of the optical path lengths is measured, and from the measured column density and the optical path length, and the column density and the optical path length read from the temporary recording unit, the concentration calculation unit calculates the column density difference and Calculate the optical path length difference, and further calculate the concentration of the detected gas
Gas concentration measuring device.
前記濃度計算部が、前記コラム密度を前記光路長で割ることにより、前記検出光の光路に沿った前記被検出ガスの平均濃度を計算する
請求項1に記載のガス濃度測定装置。
The gas concentration measurement apparatus according to claim 1, wherein the concentration calculation unit calculates an average concentration of the detected gas along the optical path of the detection light by dividing the column density by the optical path length.
前記濃度計算部が計算した前記被検出ガスの濃度を表示する表示部をさらに有し、
前記所定の照射領域が、一次元または二次元に配列された複数の副領域に区分され、
前記複数の副領域のそれぞれにおいて、前記第1状態における前記コラム密度および前記光路長の記録と前記第2状態における前記被検出ガスの濃度の計算とが行われ、
前記複数の副領域のそれぞれに対応した前記表示部の表示領域に、前記複数の副領域のそれぞれに対応した前記被検出ガスの濃度を表示する
請求項1または請求項2に記載のガス濃度測定装置。
A display unit for displaying the concentration of the detected gas calculated by the concentration calculation unit;
The predetermined irradiation area is divided into a plurality of sub-areas arranged one-dimensionally or two-dimensionally,
In each of the plurality of sub-regions, the recording of the column density and the optical path length in the first state and the calculation of the concentration of the detected gas in the second state are performed.
The gas concentration measurement according to claim 1 or 2 , wherein a concentration of the detection gas corresponding to each of the plurality of sub-regions is displayed on a display region of the display unit corresponding to each of the plurality of sub-regions. apparatus.
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