JPH11142327A - Gas detector - Google Patents
Gas detectorInfo
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- JPH11142327A JPH11142327A JP32208097A JP32208097A JPH11142327A JP H11142327 A JPH11142327 A JP H11142327A JP 32208097 A JP32208097 A JP 32208097A JP 32208097 A JP32208097 A JP 32208097A JP H11142327 A JPH11142327 A JP H11142327A
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- Japan
- Prior art keywords
- light
- gas
- laser
- wavelength
- target gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Investigating Or Analysing Materials By Optical Means (AREA)
- Examining Or Testing Airtightness (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はガス検出装置に関
し、特に、対象ガスの光吸収特性を利用してガス漏れ等
を検出するガス検出装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas detection device, and more particularly to a gas detection device that detects gas leakage and the like by utilizing the light absorption characteristics of a target gas.
【０００２】[0002]
【従来の技術】ガスには特定波長の光を吸収する吸収帯
のあることが知られており、これを利用したガス検出装
置として、例えば特開平５−２６４４４６号公報に示さ
れるような、差分吸収法によるものが知られている。こ
れは単一のレーザダイオードの駆動電流を変調して、対
象ガスに吸収される波長と吸収されない波長の二種のレ
ーザ光を交互に射出させ、途中ビームスプリッタで光束
を分岐して、一方を対象ガスを経て一の受光素子に入射
させ、他方は直接他の受光素子に入射させる。そして、
各受光素子の出力信号を対数比増幅器に入力し、その出
力を矩形波列に変換するとともに、これを帯域通過フィ
ルタに通して変調基本波成分を抽出することによりガス
濃度信号を得ている。2. Description of the Related Art It is known that a gas has an absorption band for absorbing light of a specific wavelength, and as a gas detection device utilizing this, for example, as disclosed in JP-A-5-264446. An absorption method is known. This modulates the drive current of a single laser diode, alternately emits two types of laser light of a wavelength that is absorbed by the target gas and a wavelength that is not absorbed, splits the light beam with a beam splitter on the way, and splits one. The light is incident on one light receiving element via the target gas, and the other light is directly incident on the other light receiving element. And
The gas concentration signal is obtained by inputting the output signal of each light receiving element to a logarithmic ratio amplifier, converting the output into a rectangular wave train, and passing this through a band-pass filter to extract a modulated fundamental wave component.
【０００３】[0003]
【発明が解決しようとする課題】上記従来のガス検出装
置では、レーザ光の波長を変化させるとこれに伴って光
出力も大きく変化してしまう問題を対数比増幅器を使用
することにより解決している。しかし、一般に対数比増
幅器は温度依存性が大きく、精度および信頼性に難があ
る。また、受光器を二つ使用するのも、ここでノイズが
発生し易いことを考えると、測定精度向上の観点からは
不利である。In the above-mentioned conventional gas detector, the problem that when the wavelength of the laser light is changed, the light output is also greatly changed is solved by using a logarithmic ratio amplifier. I have. However, the logarithmic ratio amplifier generally has a large temperature dependency, and is difficult in accuracy and reliability. Also, the use of two light receivers is disadvantageous from the viewpoint of improving measurement accuracy, considering that noise is likely to occur here.
【０００４】そこで、本発明はこのような課題を解決す
るもので、対数比増幅器を不要とするとともに、受光器
を一つにでき、この結果、検出精度を大きく向上させる
ことが可能なガス検出装置を提供することを目的とす
る。Accordingly, the present invention has been made to solve the above-mentioned problems, and eliminates the need for a logarithmic ratio amplifier and allows the use of a single photodetector. As a result, a gas detection system capable of greatly improving detection accuracy. It is intended to provide a device.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するた
め、本発明では、対象ガスに吸収される波長のレーザ光
を発生する第１のレーザ光発生手段（１１Ａ）と、対象
ガスに吸収されない波長のレーザ光を発生する第２のレ
ーザ光発生手段（１１Ｂ）と、第１および第２のレーザ
光発生手段（１１Ａ，１１Ｂ）で発生する各レーザ光
を、ほぼ同一振幅かつ互いに逆相に変調して変調光とす
る変調手段（１３）と、各変調光（Ｌa ，Ｌb ）を合波
して測定光（Ｌs ）とし、当該測定光（Ｌs ）を対象ガ
ス雰囲気中に出力する測定光出力手段（１２，３）と、
対象ガス雰囲気中を通過した測定光（Ｌs ）を受光する
受光手段（２３）と、受光手段（２３）の出力信号中の
変調成分を抽出する変調成分抽出手段（１５）とを具備
している。なお、「ほぼ同一振幅」とは、対象ガスの濃
度が零の時に両変調光の逆相の変調成分が互いに相殺し
合って測定光の変調成分が問題とならない程度に小さく
なるような振幅にすることをいう。In order to achieve the above object, according to the present invention, a first laser light generating means (11A) for generating a laser beam having a wavelength which is absorbed by a target gas is provided. The second laser light generating means (11B) for generating the laser light of the wavelength and the respective laser lights generated by the first and second laser light generating means (11A, 11B) have substantially the same amplitude and opposite phases. A modulating means (13) for modulating and modulating light; and a measuring light for multiplexing each modulated light (La, Lb) to form a measuring light (Ls) and outputting the measuring light (Ls) into the target gas atmosphere. Output means (12, 3);
Light receiving means (23) for receiving the measurement light (Ls) passed through the target gas atmosphere, and modulation component extracting means (15) for extracting a modulation component in an output signal of the light receiving means (23). . Note that “substantially the same amplitude” means an amplitude such that when the concentration of the target gas is zero, the modulation components of the opposite phases of the two modulated lights cancel each other out, and the modulated components of the measurement light become small enough to cause no problem. To do.
【０００６】本発明において、対象雰囲気ガスの濃度が
零であると、測定光を構成する両変調光はいずれも減衰
されず、これら変調光の逆相の変調成分が互いに相殺し
合って測定光の変調成分は問題とならない程度に小さく
なる。一方、対象雰囲気ガスの濃度が増加すると、測定
光を構成する各変調光のうち対象ガスに吸収される波長
のものがガス濃度に応じて減衰させられる。これによ
り、両変調光の逆相の変調成分に大小を生じ、この結
果、測定光の変調成分はガス濃度に応じて大きくなる。
したがって、測定光の変調成分が所定値を越えた時にこ
れを報知すれば、ガス漏れ検出器として使用できる。ま
た、測定光の変調成分を所定の数式に代入してガス濃度
を算出すれば、ガス濃度測定器として使用できる。In the present invention, when the concentration of the target atmosphere gas is zero, both modulated lights constituting the measuring light are not attenuated, and the modulated components of opposite phases of these modulated lights cancel each other out, so that the measuring light is not reflected. Is small enough to cause no problem. On the other hand, when the concentration of the target atmosphere gas increases, the modulated light constituting the measurement light having a wavelength that is absorbed by the target gas is attenuated according to the gas concentration. As a result, the magnitude of the modulation component of the opposite phase of both modulated lights is increased, and as a result, the modulated component of the measurement light increases according to the gas concentration.
Therefore, if this is notified when the modulation component of the measurement light exceeds a predetermined value, it can be used as a gas leak detector. Further, if the gas concentration is calculated by substituting the modulation component of the measurement light into a predetermined mathematical formula, it can be used as a gas concentration measuring device.
【０００７】本発明によれば対数比増幅器が不要である
とともに単一の受光器を設ければ良いから、温度変化に
よる特性変化やノイズの混入による精度低下をきたすこ
となく、高精度なガス検出が可能である。また、測定光
の変調成分のみを抽出するから、各レーザ光発生手段で
発生させられる非変調時のレーザ光強度にある程度の差
があっても問題とならない。According to the present invention, since a logarithmic ratio amplifier is not required and a single photodetector can be provided, high-precision gas detection can be performed without causing a change in characteristics due to a change in temperature or a decrease in accuracy due to mixing of noise. Is possible. Further, since only the modulation component of the measurement light is extracted, there is no problem even if there is a certain difference in the intensity of the laser light at the time of non-modulation generated by each laser light generating means.
【０００８】なお、上記カッコ内の符号は、後述する実
施形態に記載の具体的手段との対応関係を示すものであ
る。[0008] The reference numerals in parentheses indicate the correspondence with specific means described in the embodiments described later.
【０００９】[0009]
【発明の実施の形態】（第１実施形態）図１にはガス検
出装置の構成を示す。装置はコントローラ部１とプロー
ブ部２よりなり、コントローラ部１には２個のレーザダ
イオード（ＬＤ）１１Ａ，１１Ｂ、合波器１２、変調信
号調整回路１３、信号発生回路１４、同期検波回路１
５、演算回路１６および表示器１７が設けられている。
また、プローブ部２にはコリメータレンズ２１と集光レ
ンズ２２、および受光器２３が設けられている。(First Embodiment) FIG. 1 shows the configuration of a gas detector. The device comprises a controller unit 1 and a probe unit 2. The controller unit 1 includes two laser diodes (LDs) 11A and 11B, a multiplexer 12, a modulation signal adjustment circuit 13, a signal generation circuit 14, and a synchronous detection circuit 1.
5, an arithmetic circuit 16 and a display 17 are provided.
The probe section 2 is provided with a collimator lens 21, a condenser lens 22, and a light receiver 23.
【００１０】上記レーザダイオード１１Ａは対象ガスに
吸収される波長λ1 のレーザ光を発振し、一方、レーザ
ダイオード１１Ｂは対象ガスに吸収されない波長λ2 の
レーザ光を発振する。なお、レーザダイオード１１Ａに
より発生させられるレーザ光はそのスペクトル幅が対象
ガスの吸収線幅よりも狭いことが望ましい。また、両レ
ーザダイオード１１Ａ，１１Ｂにより発生させられるレ
ーザ光は、ガス雰囲気中に他のガスが存在する場合に、
それらのガスで吸収されない波長であることが望まし
い。本実施形態では、各レーザ光の波長λ1 ，λ2 は
１．６５μｍ帯を使用しており、これら波長λ1 ，λ2
は、屈折率等の光学的特性を類似させるために可能な限
り近い波長とするのが良い。The laser diode 11A oscillates a laser beam having a wavelength λ1 which is absorbed by the target gas, while the laser diode 11B oscillates a laser beam having a wavelength λ2 which is not absorbed by the target gas. It is desirable that the laser beam generated by the laser diode 11A has a spectrum width narrower than the absorption line width of the target gas. Further, the laser light generated by the laser diodes 11A and 11B is generated when other gas exists in the gas atmosphere.
It is desirable that the wavelength is not absorbed by those gases. In this embodiment, the wavelengths .lambda.1, .lambda.2 of each laser beam use the 1.65 .mu.m band.
Is preferably set to a wavelength as close as possible to make optical characteristics such as a refractive index similar.
【００１１】信号発生器１４から出力される５ＫＨｚの
正弦波あるいは矩形波の出力信号は変調信号調整回路１
３に入力し、変調信号調整回路１３では所定の変調比で
逆位相の変調信号１３ａ，１３ｂをそれぞれレーザダイ
オード１１Ａ，１１Ｂに出力する。なお、各レーザダイ
オード１１Ａ，１１Ｂに対する強度変調比は、合波器１
２におけるレーザ光Ｌａ，Ｌｂの混合比率をＭa ，Ｍb
とし、受光器２３における各レーザ光Ｌａ，Ｌｂの感度
をγa ，γb として、Ｍb γb ：Ｍa γa とする。レー
ザダイオード１１Ａ，１１Ｂから出力される各変調光Ｌ
a ，Ｌb の光強度の経時変化を図２（Ａ），（Ｂ）に示
し、それぞれ非変調時の所定強度Ｉ1 ，Ｉ2 を中心に５
ＫＨｚでほぼ同一振幅かつ互いに逆位相に変調されてい
る。A 5 KHz sine wave or rectangular wave output signal output from the signal generator 14 is applied to the modulation signal adjusting circuit 1.
3, and the modulation signal adjusting circuit 13 outputs modulation signals 13a and 13b of opposite phases at a predetermined modulation ratio to the laser diodes 11A and 11B, respectively. The intensity modulation ratio for each of the laser diodes 11A and 11B is
2, the mixing ratio of the laser beams La and Lb is defined as Ma, Mb.
It is assumed that the sensitivity of the laser beams La and Lb in the light receiver 23 is γa and γb, and that Mb γb: Ma γa. Modulated light L output from laser diodes 11A and 11B
2 (A) and 2 (B) show the change over time of the light intensity of a and Lb.
It is modulated at KHz with substantially the same amplitude and opposite phases.
【００１２】各レーザダイオード１１Ａ，１１Ｂから出
力された変調光Ｌa ，Ｌb は方向性結合器を使用した合
波器１２に入力し、ここで合波されて測定光Ｌs とな
る。測定光Ｌs の光強度の経時変化を図２（Ｃ）に示
し、変調成分が互いに相殺されて殆ど脈動の無い一定強
度となっている。なお、合波器１２としては方向性結合
器を使用する以外に、例えばハーフミラー等を使用する
こともできる。The modulated lights La and Lb output from the laser diodes 11A and 11B are input to a multiplexer 12 using a directional coupler, where they are multiplexed to become measurement light Ls. FIG. 2C shows the temporal change of the light intensity of the measurement light Ls, and the modulated components cancel each other out to have a constant intensity with almost no pulsation. In addition to the use of the directional coupler as the multiplexer 12, for example, a half mirror or the like can be used.
【００１３】測定光Ｌs は光ファイバ３によってプロー
ブ部２へ導入され、コリメータレンズ２１で平行光に変
換されて対象ガス雰囲気中へ送出される。対象ガス雰囲
気中を通過した測定光Ｌs は集光レンズ２２によって、
フォトダイオードあるいは光電子増倍管を使用した受光
器２３に入力する。測定光Ｌs のうち波長λ1 の成分は
対象ガス雰囲気を通過する際に吸収され、ガス濃度に応
じて減衰させられる。対象ガスの濃度が零であれば波長
λ1 の測定光成分は全く減衰させられないから、変調分
が互いに相殺しあった一定強度の測定光Ｌs が受光器２
３に入力し、受光器２３の出力は図３（Ａ）に示すよう
に一定となる。一方、対象ガスの濃度が零以外である
と、波長λ1 の測定光成分は吸収によってガス濃度に応
じて減衰させられ（図２（Ａ）の破線参照）、このた
め、受光器２３の出力には波長λ1 の測定光成分と波長
λ2 の測定光成分の差分に応じた変調成分が現れる（図
４（Ａ））。The measuring light Ls is introduced into the probe section 2 by the optical fiber 3, converted into parallel light by the collimator lens 21, and sent out into the target gas atmosphere. The measurement light Ls that has passed through the target gas atmosphere is
The light is input to a light receiver 23 using a photodiode or a photomultiplier tube. The component of the wavelength λ1 of the measurement light Ls is absorbed when passing through the target gas atmosphere and is attenuated according to the gas concentration. If the concentration of the target gas is zero, the measurement light component of the wavelength λ1 is not attenuated at all, so that the measurement light Ls of a constant intensity, in which the modulated components cancel each other, is applied to the light receiver 2.
3 and the output of the photodetector 23 becomes constant as shown in FIG. On the other hand, when the concentration of the target gas is other than zero, the measurement light component having the wavelength λ1 is attenuated by absorption according to the gas concentration (see the broken line in FIG. 2A). Shows a modulation component corresponding to the difference between the measurement light component of the wavelength λ1 and the measurement light component of the wavelength λ2 (FIG. 4A).
【００１４】受光器２３の出力はコントローラ部１の同
期検波回路１５に入力する。同期検波回路１５には上記
信号発生回路１４の５ＫＨｚ信号が入力しており、受光
器２３の出力のうち変調成分ＩM のみが抽出される（図
４（Ｂ））。この変調成分ＩM は対象ガス濃度が零の場
合には零となる（図３（Ｂ））。抽出された変調成分Ｉ
M は演算回路１６に入力し、下式（１）によってガス濃
度αが算出されて、表示器１７上に表示される。The output of the light receiver 23 is input to the synchronous detection circuit 15 of the controller 1. The synchronous detection circuit 15 receives the 5 KHz signal of the signal generation circuit 14 and extracts only the modulation component IM from the output of the photodetector 23 (FIG. 4B). This modulation component IM becomes zero when the target gas concentration is zero (FIG. 3B). Modulated component I extracted
M is input to the arithmetic circuit 16 and the gas concentration α is calculated by the following equation (1) and displayed on the display 17.
【００１５】 α＝−１／ＫＬ・ｌｏｇ（１−ＩM ／Ｉ0 ）……（１） ＝−１／ＫＬ・ｌｏｇ（１−（Ｉb −Ｉa ）／Ｉb ） ＝−１／ＫＬ・ｌｏｇ（Ｉa ／Ｉb ）Α = −1 / KL·log (1-IM / I 0) (1) = − 1 / KL·log (1− (Ib−Ia) / Ib) = − 1 / KL·log (Ia) / Ib)
【００１６】なお、上式（１）において、Ｉ0 （＝Ｉb
）は変調光Ｌa をカットした時の対象ガス通過後の測
定光Ｌs 中の変調成分強度であり、Ｉa ，Ｉb はそれぞ
れ、対象ガス通過後の測定光Ｌs 中の変調光Ｌａ，Ｌｂ
の変調成分強度である。また、Ｋは対象ガスの吸収係
数、Ｌは対象ガス雰囲気中の光路長である。In the above equation (1), I0 (= Ib
) Is the intensity of the modulated component in the measurement light Ls after passing through the target gas when the modulated light La is cut off, and Ia and Ib are the modulated lights La and Lb in the measurement light Ls after passing through the target gas, respectively.
Is the intensity of the modulated component. K is the absorption coefficient of the target gas, and L is the optical path length in the target gas atmosphere.
【００１７】上記実施形態では、演算回路１６でガス濃
度αを算出するようにしたが、単にガス漏れ検出の用途
に使用する場合には、演算回路１６を設けず、同期検波
回路１５の出力すなわち変調成分ＩM が所定値を越えた
時に警報信号を発するような構成とすれば良い。In the above embodiment, the gas concentration α is calculated by the arithmetic circuit 16. However, when the gas concentration α is simply used for gas leak detection, the arithmetic circuit 16 is not provided, and the output of the synchronous detection circuit 15, ie, The configuration may be such that an alarm signal is issued when the modulation component IM exceeds a predetermined value.
【００１８】変調成分抽出手段としては上記実施形態の
同期検波回路に代えて、受光器の出力をフーリエ変換し
て変調成分強度を測定するもの、あるいは受光器出力と
変調信号との相互相関をとるもの等が採用できる。As the modulation component extracting means, one which measures the intensity of the modulation component by Fourier transforming the output of the optical receiver instead of the synchronous detection circuit of the above-described embodiment, or obtains the cross-correlation between the output of the optical receiver and the modulation signal. Things can be adopted.
【００１９】（第２実施形態）プローブ部の構成は図５
に示すようなものとしても良い。すなわち、図５におい
て、プローブ部にはコリメータレンズ２１、集光レンズ
２２、および受光器２３に加えて、ハーフミラー２４が
設けられている。他の構成は第１実施形態と同様であ
る。(Second Embodiment) FIG.
It is good also as what is shown in. That is, in FIG. 5, the probe unit is provided with a half mirror 24 in addition to the collimator lens 21, the condenser lens 22, and the light receiver 23. Other configurations are the same as those of the first embodiment.
【００２０】コントローラ部（図１参照）から至った光
ファイバ３によりコリメータレンズ２１に測定光Ｌc が
導入され、これはハーフミラー２４で反射されて対象ガ
ス雰囲気中へ送出される。対象ガス雰囲気を通過した測
定光Ｌc は室壁Ｗ等の反射体あるいは散乱体で反射ない
し散乱される。測定光Ｌc のうち反射等されて対象ガス
雰囲気中を再び戻った光はハーフミラー２４を通過して
集光レンズ２２に至り、受光器２３に入射させられる。The measuring light Lc is introduced into the collimator lens 21 by the optical fiber 3 from the controller (see FIG. 1), and is reflected by the half mirror 24 and sent out into the target gas atmosphere. The measurement light Lc that has passed through the target gas atmosphere is reflected or scattered by a reflector or scatterer such as the chamber wall W. Of the measurement light Lc, the light that has been reflected and returned again in the target gas atmosphere passes through the half mirror 24, reaches the condenser lens 22, and enters the light receiver 23.
【００２１】このような構成によっても、第１実施形態
と同様の作用効果が得られるとともに、コリメータレン
ズ２１と集光レンズ２２を第１実施形態のように対象ガ
ス雰囲気を挟んで対称位置に設ける必要がなく、同じ側
に設けることができるから、プローブ部が小型化される
とともに、対象ガス雰囲気から離れた遠隔からのガス検
出が可能となる。With such a configuration, the same operation and effect as those of the first embodiment can be obtained, and the collimator lens 21 and the condenser lens 22 are provided at symmetric positions with respect to the target gas atmosphere as in the first embodiment. Since it is not necessary and can be provided on the same side, the probe section can be miniaturized and gas can be remotely detected away from the target gas atmosphere.
【００２２】[0022]
【発明の効果】以上のように、本発明のガス検出装置に
よれば、対数比増幅器を不要とするとともに、受光器を
一つにできるから、検出精度を大きく向上させることが
できる。As described above, according to the gas detection device of the present invention, the logarithmic ratio amplifier is not required and the number of light receivers can be one, so that the detection accuracy can be greatly improved.
【図１】本発明の第１実施形態を示す、ガス検出装置の
ブロック構成図である。FIG. 1 is a block diagram of a gas detection device according to a first embodiment of the present invention.
【図２】光強度の経時変化を示す図である。FIG. 2 is a diagram showing a change over time in light intensity.
【図３】受光器出力と同期検波出力の経時変化を示す図
である。FIG. 3 is a diagram showing a temporal change of a photodetector output and a synchronous detection output.
【図４】受光器出力と同期検波出力の経時変化を示す図
である。FIG. 4 is a diagram showing a temporal change of a photodetector output and a synchronous detection output.
【図５】本発明の第２実施形態を示す、ガス検出装置の
プローブ部の概略構成図である。FIG. 5 is a schematic configuration diagram of a probe unit of a gas detection device according to a second embodiment of the present invention.
１１Ａ，１１Ｂ…レーザダイオード、１２…合波器、１
３…変調信号調整回路、１５…同期検波回路、２３…受
光器、３…光ファイバ、Ｌa ，Ｌb …変調光、Ｌs …測
定光。11A, 11B: laser diode, 12: multiplexer, 1
Reference numeral 3 denotes a modulation signal adjusting circuit, 15 denotes a synchronous detection circuit, 23 denotes a light receiver, 3 denotes an optical fiber, La and Lb denotes modulated light, and Ls denotes measurement light.
Claims (1)
発生する第１のレーザ光発生手段と、対象ガスに吸収さ
れない波長のレーザ光を発生する第２のレーザ光発生手
段と、前記第１および第２のレーザ光発生手段で発生す
る各レーザ光を、ほぼ同一振幅かつ互いに逆相に変調し
て変調光とする変調手段と、前記各変調光を合波して測
定光とし、当該測定光を対象ガス雰囲気中に出力する測
定光出力手段と、対象ガス雰囲気中を通過した前記測定
光を受光する受光手段と、当該受光手段の出力信号中の
変調成分を抽出する変調成分抽出手段とを具備するガス
検出装置。A first laser light generating means for generating a laser light having a wavelength which is absorbed by the target gas; a second laser light generating means for generating a laser light having a wavelength not absorbed by the target gas; A modulating means for modulating each laser light generated by the first and second laser light generating means to have substantially the same amplitude and opposite phases to each other to form modulated light; Measurement light output means for outputting the measurement light into the target gas atmosphere, light reception means for receiving the measurement light passing through the target gas atmosphere, and modulation component extraction means for extracting a modulation component in an output signal of the light reception means A gas detection device comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32208097A JPH11142327A (en) | 1997-11-08 | 1997-11-08 | Gas detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32208097A JPH11142327A (en) | 1997-11-08 | 1997-11-08 | Gas detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11142327A true JPH11142327A (en) | 1999-05-28 |
Family
ID=18139696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32208097A Pending JPH11142327A (en) | 1997-11-08 | 1997-11-08 | Gas detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11142327A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010145320A (en) * | 2008-12-22 | 2010-07-01 | General Packer Co Ltd | Gas measuring instrument |
| US10302563B2 (en) | 2013-08-21 | 2019-05-28 | Tokushima University | Apparatus and method of gas analysis using laser light |
-
1997
- 1997-11-08 JP JP32208097A patent/JPH11142327A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010145320A (en) * | 2008-12-22 | 2010-07-01 | General Packer Co Ltd | Gas measuring instrument |
| US10302563B2 (en) | 2013-08-21 | 2019-05-28 | Tokushima University | Apparatus and method of gas analysis using laser light |
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