JPH06308008A - Method and apparatus for identifying mixed gas component - Google Patents
Method and apparatus for identifying mixed gas componentInfo
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- JPH06308008A JPH06308008A JP9969693A JP9969693A JPH06308008A JP H06308008 A JPH06308008 A JP H06308008A JP 9969693 A JP9969693 A JP 9969693A JP 9969693 A JP9969693 A JP 9969693A JP H06308008 A JPH06308008 A JP H06308008A
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- gas
- component
- crystal oscillator
- resonance frequency
- time constant
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は表面にガス吸着膜を設け
た水晶発振子を用い、被検知ガスの前記ガス吸着膜への
吸着による前記水晶発振子の共振周波数の変化を求める
ことにより混合ガス中の各成分ガスの種類を同定し、か
つ濃度を定量する混合ガス成分判別および定量方法なら
びに装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a crystal oscillator provided with a gas adsorption film on the surface thereof, and obtains a change in the resonance frequency of the crystal oscillator due to the adsorption of a gas to be detected on the gas adsorption film to achieve mixing. The present invention relates to a mixed gas component discrimination and quantification method and apparatus for identifying the type of each component gas in gas and quantifying the concentration.
【０００２】[0002]
【従来の技術】化学物質を測定する化学センシング装置
においては、簡単、安価な構成で微量の被検知ガスを感
度良く検知し、判別する必要がある。従来よりこのよう
なガス判別方法として、表面にガス吸着膜（以下単に吸
着膜と称する）を設けた水晶発振子を用いる方法があ
る。この方法は、被検知ガス分子がこの吸着膜に吸着し
たとき、水晶発振子の共振周波数が吸着膜の質量変化に
比例して変化することを利用するものであり、共振周波
数の最大変化量から被検知ガスの種類、濃度を同定する
ものである。この方法においては、吸着膜がある特定の
ガスのみに感応するものである場合を除き、複数の水晶
発振子が必要となり、それぞれの水晶発振子の飽和吸着
量の値からパタン認識等の方法によって同定を行ってい
た。2. Description of the Related Art In a chemical sensing device for measuring a chemical substance, it is necessary to detect and discriminate a small amount of a target gas with high sensitivity by a simple and inexpensive structure. Conventionally, as such a gas discriminating method, there is a method using a crystal oscillator having a gas adsorption film (hereinafter simply referred to as an adsorption film) provided on the surface. This method uses the fact that when the gas molecules to be detected are adsorbed on this adsorption film, the resonance frequency of the crystal oscillator changes in proportion to the mass change of the adsorption film. The type and concentration of the gas to be detected are identified. In this method, a plurality of crystal oscillators are required unless the adsorption film is sensitive only to a specific gas, and a method such as pattern recognition is used from the saturated adsorption amount value of each crystal oscillator. I was identifying.
【０００３】[0003]
【発明が解決しようとする課題】上述した従来の混合ガ
ス成分判別方法では以下のような欠点があった。すなわ
ち、ある特定のガスのみに感応するような吸着膜を開発
すること自体困難であり、たいていは複数の水晶発振子
を用いることになる。その場合、混合ガス中の各成分ガ
スを同定するには、まず、少なくとも成分ガスと同数以
上の異なる吸着特性を持つ吸着膜を用意しなければなら
ず、コストが高くなる。また、成分ガスの種類およびそ
の濃度が既知の混合ガスに対する各吸着膜を被覆した水
晶発振子の飽和吸着量をデータベースとして用意し、パ
タンマッチングによって各成分ガスを同定しなければな
らないが、ある混合ガスとそれに対する各吸着膜を被覆
した水晶発振子の飽和吸着量のパターンは一対一対応し
ないため、混合ガス中の成分ガスの判別を正確に行うこ
とができないのが現状である。さらに、各成分ガスの定
量も困難である。The above-mentioned conventional mixed gas component determination method has the following drawbacks. That is, it is difficult to develop an adsorption film that is sensitive only to a specific gas, and usually a plurality of crystal oscillators are used. In that case, in order to identify each component gas in the mixed gas, first, it is necessary to prepare an adsorption film having at least the same number of different adsorption characteristics as the component gas, which increases the cost. In addition, it is necessary to prepare as a database the saturated adsorption amount of the crystal oscillator coated with each adsorption film for the mixed gas of which the type and concentration of the component gas are known, and to identify each component gas by pattern matching. At present, it is not possible to accurately discriminate the component gases in the mixed gas, because the patterns of the saturated adsorption amount of the gas and the quartz oscillator coated with the respective adsorption films do not correspond one-to-one. Furthermore, it is difficult to quantify each component gas.
【０００４】本発明の目的は、複数の種類のガス成分に
感応する吸着膜を設けた一つの水晶発振子だけで混合ガ
ス中の成分ガスの種類を確実に同定し、かつ濃度を定量
できる混合ガス成分判別および定量方法ならびに装置を
提供することにある。An object of the present invention is to provide a single crystal oscillator provided with an adsorption film sensitive to a plurality of kinds of gas components, so that the kind of the component gas in the mixed gas can be surely identified and the concentration can be quantified. It is intended to provide a gas component discrimination and quantification method and apparatus.
【０００５】[0005]
【課題を解決するための手段】本発明の混合ガス成分判
別および定量方法は、ガス吸着膜を表面に設けた一つの
水晶発振子を用い、前記水晶発振子の共振周波数の時間
変化に含まれる指数関数の時定数を検出する手順と、前
記手順により検出された水晶発振子の共振周波数の時間
変化に含まれる指数関数の時定数と、各成分ガスの単独
ガスの場合の共振周波数の時間変化を表わす指数関数の
時定数とを比較して一致するか否かにより、各成分ガス
の種類の同定を行う手順と、各成分ガスの前記ガス吸着
膜への飽和吸着量を求めて各成分ガスの濃度の定量を行
う手順とを含む。The method for discriminating and quantifying a mixed gas component according to the present invention uses one crystal oscillator provided with a gas adsorption film on the surface thereof, and is included in the time variation of the resonance frequency of the crystal oscillator. Procedure for detecting time constant of exponential function, time constant of exponential function included in time change of resonance frequency of crystal oscillator detected by the procedure, and time change of resonance frequency in case of individual gas of each component gas Is compared with the time constant of the exponential function and whether or not they match, the procedure for identifying the type of each component gas and the saturated adsorption amount of each component gas to the gas adsorption film are calculated for each component gas. And a procedure for quantifying the concentration of
【０００６】水晶発振子の共振周波数の時間変化に含ま
れる指数関数の時定数の検出に線型フィルタのアルゴリ
ズムを用いてもよい。A linear filter algorithm may be used to detect the exponential time constant included in the time change of the resonance frequency of the crystal oscillator.
【０００７】本発明の混合ガス成分判別および定量装置
は、ガス吸着膜が表面に設けられた単一の水晶発振子が
配置された測定セルと、前記測定セルにガス試料を供給
するガス供給器と、前記測定セルにガス試料が供給され
たとき、前記水晶発振子の共振周波数で発振する発振回
路と、前記発振回路が発振する水晶発振子の共振周波数
をカウントする周波数カウンタと、表示装置と、前記周
波数カウンタでカウントされた、前記ガス試料のガス吸
着膜への吸着による水晶発振子の共振周波数の時間変化
に含まれる指数関数の時定数を検出し、前記測定セルに
供給されたガス試料の各成分ガスの単独ガスの場合の共
振周波数の時間変化を表わす指数関数の時定数とを比較
して一致するか否かにより各成分ガスの種類の同定を行
い、かつ各成分ガスの前記吸着膜への飽和吸着量を求め
て各成分ガスの濃度の定量を行い、結果を前記表示装置
に表示するコンピュータとを有する。A mixed gas component discriminating and quantifying apparatus of the present invention comprises a measuring cell in which a single crystal oscillator having a gas adsorption film on the surface is arranged, and a gas supplier for supplying a gas sample to the measuring cell. An oscillation circuit that oscillates at the resonance frequency of the crystal oscillator when a gas sample is supplied to the measurement cell, a frequency counter that counts the resonance frequency of the crystal oscillator oscillated by the oscillation circuit, and a display device. A gas sample supplied to the measuring cell, which detects the time constant of an exponential function included in the time variation of the resonance frequency of the crystal oscillator due to the adsorption of the gas sample to the gas adsorption film, which is counted by the frequency counter. Each component gas is identified by comparing it with the time constant of the exponential function that represents the time change of the resonance frequency in the case of a single component gas, and identifying the type of each component gas. The seeking saturated adsorption amount to the adsorption film performs quantification of the concentration of each component gas, and a computer which displays the results on the display device.
【０００８】水晶発振子のガス吸着膜にプラズマ由来の
含弗素系高分子薄膜が用いられたものを含む。This includes one in which a fluorine-containing polymer thin film derived from plasma is used as the gas adsorption film of the crystal oscillator.
【０００９】[0009]
【作用】吸着膜を設けた単一の水晶発振子を用いて、前
記水晶発振子の共振周波数の時間変化に含まれる指数関
数の時定数を検出して、各成分ガスの単独の場合の指数
関数の時定数と比較して、各成分ガスの種類の同定と濃
度の定量を行うので、装置が安価となるとともに、正確
な結果が得られる。By using a single crystal oscillator provided with an adsorption film, the time constant of an exponential function included in the time change of the resonance frequency of the crystal oscillator is detected, and the exponent of each component gas alone is detected. Since the type of each component gas is identified and the concentration is quantified by comparing with the time constant of the function, the apparatus is inexpensive and accurate results can be obtained.
【００１０】[0010]
【実施例】次に、本発明の実施例について図面を参照し
て説明する。Embodiments of the present invention will now be described with reference to the drawings.
【００１１】図１は本発明の混合ガス成分判別および定
量装置の一実施例の構成ブロック図、図２は図１のコン
ピュータ６の処理のフローチャート、図３は図１の水晶
発振子３の単独ガスおよび混合ガスに対する共振周波数
の時間変化、すなわち圧電応答の一具体例を示すグラ
フ、図４は図３圧電応答から得られた単独ガスおよび混
合ガスの時定数および飽和吸着量を示すグラフである。FIG. 1 is a block diagram showing the configuration of an embodiment of the mixed gas component discriminating and quantifying device of the present invention, FIG. 2 is a flowchart of the processing of the computer 6 of FIG. 1, and FIG. 3 is the crystal oscillator 3 alone of FIG. FIG. 4 is a graph showing a specific example of the piezoelectric response with respect to the time change of the resonance frequency with respect to the gas and the mixed gas, and FIG. 4 is a graph showing the time constant and the saturated adsorption amount of the single gas and the mixed gas obtained from the piezoelectric response of FIG. .
【００１２】本発明は吸着膜への被検知ガス分子の吸着
過程を詳細に検討した結果なされたものである。ここ
で、その検討結果について説明する。The present invention has been made as a result of detailed examination of the adsorption process of the gas molecules to be detected on the adsorption film. Here, the examination result will be described.
【００１３】ポリエチレンとポリテトラフロロエチレン
両方をタ−ゲットとして高周波スパッタリングによって
水晶発振子上に吸着を膜形成し、この吸着膜への被検知
ガス分子の吸着による水晶発振子の共振周波数の変化を
調べた。水晶発振子の共振周波数は、吸着膜の質量変化
すなわち吸着した被検知ガスの質量に比例することが知
られている。その結果、被検知ガスが通常の有機化合
物、例えば各種のアルコール、芳香族化合物、ケトンで
ある場合、被検知ガスを全く吸着していない状態のこの
吸着膜を一定濃度の被検知ガスに曝したところ、ある一
定時間Δｔごとにサンプリングした（時刻ｋ・Δｔ）に
おける共振周波数の時間変化、つまり吸着量ｍ［ｋ］はAdsorption is formed as a film on the crystal oscillator by high frequency sputtering using both polyethylene and polytetrafluoroethylene as targets, and changes in the resonance frequency of the crystal oscillator due to the adsorption of gas molecules to be detected on the adsorption film. Examined. It is known that the resonance frequency of the crystal oscillator is proportional to the mass change of the adsorption film, that is, the mass of the adsorbed gas to be detected. As a result, when the gas to be detected is a normal organic compound such as various alcohols, aromatic compounds, and ketones, this adsorption film in a state in which the gas to be detected is not adsorbed is exposed to a gas having a certain concentration. However, the time change of the resonance frequency at the time (time k · Δt) sampled at every certain time Δt, that is, the adsorption amount m [k] is
【００１４】[0014]
【数１】 ｍ［ｋ］＝ａ（１−ｅｘｐ（−ｋ・Δｔ／τ）） と表わされるようになる。## EQU1 ## m [k] = a (1-exp (-k.Δt / τ))
【００１５】ここで、ｅｘｐはイクスポーネンシャル、
すなわち指数関数で，ｋは時刻を表わす変数（整数）、
Δｔはサンプリング時間、ａは被検知ガスの飽和吸着量
を表わしており、また、時定数τは、被検知ガスの種類
に深く関わっていることが分かっている。Where exp is an exponential,
That is, with an exponential function, k is a variable (integer) representing time,
It is known that Δt represents the sampling time, a represents the saturated adsorption amount of the gas to be detected, and the time constant τ is deeply related to the type of gas to be detected.
【００１６】混合ガス（ｎ種類の成分ガスを含む）に対
する水晶発振子の共振周波数の時間変化ｍ［ｋ］は次の
ように指数関数の和で表わされることが分かっている。It has been known that the time variation m [k] of the resonance frequency of the crystal oscillator with respect to the mixed gas (including n kinds of component gases) is represented by the sum of exponential functions as follows.
【００１７】[0017]
【数２】 ここで各成分ガスの時定数τj は混合ガス中でも変化し
ないため、予め各成分ガスの標準試料に対して時定数を
測定しておき、後に述べる線型フィルタのアルゴリスム
によって測定データから上式τj すなわち各成分ガスの
時定数とａj すなわち各成分ガスの飽和吸着量を抽出
し、標準試料の時定数と比較すれば各成分ガスの種類を
同定することができる。濃度が同じならば混合ガスでも
単独ガスでも飽和吸着量は同じであることから、各成分
ガスの飽和吸着量から濃度の定量もできる。[Equation 2] Here, since the time constant τ j of each component gas does not change even in the mixed gas, the time constant is measured beforehand with respect to the standard sample of each component gas, and the above equation τ j is calculated from the measurement data by the algorithm of the linear filter described later. That is, the type of each component gas can be identified by extracting the time constant of each component gas and a j, that is, the saturated adsorption amount of each component gas and comparing with the time constant of the standard sample. If the concentration is the same, the saturated adsorption amount is the same for both the mixed gas and the single gas. Therefore, the concentration can be quantitatively determined from the saturated adsorption amount of each component gas.
【００１８】次に、本実施例の混合ガス成分判別および
定量装置について説明する。Next, the mixed gas component discriminating and quantifying device of this embodiment will be described.
【００１９】この混合ガス成分判別および定量装置は図
１に示すように、測定セル１と水晶発振子３と発振回路
４と周波数カウンタ５とコンピュータ６と表示装置７と
ガス供給器８とから構成される。As shown in FIG. 1, this mixed gas component discriminating and quantifying device comprises a measuring cell 1, a crystal oscillator 3, an oscillating circuit 4, a frequency counter 5, a computer 6, a display device 7 and a gas supplier 8. To be done.
【００２０】ガス供給器８はポンプ等の吸引機能を持っ
ていて測定セル１に定常的にガス試料を供給する。測定
セル１には、１つの水晶発振子３が配置されている、水
晶発振子３の表面には、吸着膜２が設けられている。こ
こで吸着膜２は、ポリエチレンとポリテトラフロロエチ
レンをターゲットとしてスパッタリングを行って水晶発
振子３の表面に被覆を行うことによって形成されている
が、例えば、グラファイト、ポリフロロトリフルオロエ
チレン等をターゲットとして形成された他のプラズマ由
来の含弗素系高分子薄膜であってもよい。発振回路４は
水晶発振子３の共振周波数で発振する。周波数カウンタ
５は発振回路４が発振した水晶発振子３の共振周波数を
カウントする。The gas supplier 8 has a suction function such as a pump and constantly supplies the gas sample to the measuring cell 1. One crystal oscillator 3 is arranged in the measurement cell 1, and an adsorption film 2 is provided on the surface of the crystal oscillator 3. Here, the adsorption film 2 is formed by sputtering polyethylene and polytetrafluoroethylene as targets to coat the surface of the crystal oscillator 3. For example, graphite, polyfluorotrifluoroethylene, or the like is used as a target. It may be another plasma-derived fluorine-containing polymer thin film formed as described above. The oscillator circuit 4 oscillates at the resonance frequency of the crystal oscillator 3. The frequency counter 5 counts the resonance frequency of the crystal oscillator 3 oscillated by the oscillation circuit 4.
【００２１】コンピュータ６は、周波数カウンタ５で計
測された発振回路４の発振周波数の変化を追跡し、水晶
発振子３の共振周波数の変化から、ガス試料中の各成分
ガスの時定数、飽和吸着量を抽出し、測定セル１内の成
分ガスの種類の同定、濃度の定量を行う。また、コンピ
ュータ６には表示装置７が接続されており、水晶発振子
３の圧電応答、成分ガスの同定結果および濃度を表示す
る。The computer 6 tracks changes in the oscillation frequency of the oscillation circuit 4 measured by the frequency counter 5, and based on the changes in the resonance frequency of the crystal oscillator 3, the time constant of each component gas in the gas sample and the saturation adsorption. The amount is extracted, the type of the component gas in the measurement cell 1 is identified, and the concentration is quantified. Further, a display device 7 is connected to the computer 6, and displays the piezoelectric response of the crystal oscillator 3, the identification result of the component gas and the concentration.
【００２２】以下コンピュータ６における処理を図２の
フローチャートによって詳細に説明する。The processing in the computer 6 will be described in detail below with reference to the flowchart of FIG.
【００２３】まず、コンピュータ６は各標準試料に対す
る水晶発振子３の圧電応答曲線から、各標準試料の飽和
吸着量ａ、時定数τを求める（ステップ１１）。この応
答曲線は一つの指数関数を含む式で表わされるので時定
数、飽和吸着量の推定は容易である。First, the computer 6 obtains the saturated adsorption amount a and the time constant τ of each standard sample from the piezoelectric response curve of the crystal oscillator 3 for each standard sample (step 11). Since this response curve is expressed by an equation including one exponential function, it is easy to estimate the time constant and the saturated adsorption amount.
【００２４】次に、測定セル１に測定しようとする混合
ガスが導入されると、混合ガスに対する水晶発振子３の
圧電応答を獲得する（ステップ１２）。ここで以下のよ
うな線型フィルタのアルゴリズムに従って圧電応答曲線
に含まれる指数関数の時定数τj 、飽和吸着量ａj を抽
出する（ステップ１３）。Next, when the mixed gas to be measured is introduced into the measuring cell 1, the piezoelectric response of the crystal oscillator 3 to the mixed gas is obtained (step 12). Here, the time constant τ j of the exponential function and the saturated adsorption amount a j included in the piezoelectric response curve are extracted according to the following linear filter algorithm (step 13).
【００２５】すなわち、時刻ｋ・Δｔから時刻（Ｋ−
Ｐ）・Δｔまでの吸着量からなるベクトルＭを Ｍ＝（ｍ［ｋ］，ｍ［ｋ−１］，・・・ｍ［ｋ−Ｐ］）
T ， 時刻（ｋ−１）・Δｔから時刻（ｋ−Ｐ−Ｌ）・Δｔま
での吸着量からなる（Ｐ＋１）×Ｌの行列φをThat is, from time k · Δt to time (K-
P). The vector M consisting of the adsorption amount up to Δt is M = (m [k], m [k-1], ... M [k-P])
T , (P + 1) × L matrix φ consisting of the adsorption amount from time (k−1) · Δt to time (k−P−L) · Δt
【００２６】[0026]
【数３】 およびＰ＞Ｌ＞ｎとしたとき、 （１）Ｂ＝｛φT φ｝-1φT Ｍを計算し、 Ｂ＝（ｂ1 ，ｂ2 ，・・・・ｂL ）T を得る。[Equation 3] And P>L> n, (1) B = {φ T φ} −1 φ T M is calculated to obtain B = (b 1 , b 2 , ..., B L ) T.
【００２７】（２）（１）で得られたｂj を用いて、Ｘ
についての方程式(2) Using b j obtained in (1), X
Equation for
【００２８】[0028]
【数４】 を解く。この実数解を[Equation 4] Solve This real solution
【００２９】[0029]
【数５】 とする。[Equation 5] And
【００３０】（３）時定数τj ＝−Δｔ／ｌｏｇ（ｒ
j ）を求める。(3) Time constant τ j = -Δt / log (r
j ).
【００３１】この値のうち、絶対値の一番大きいもの
（τ1 とする）を除いた残りの時定数が各成分ガスの時
定数である。各成分ガスの飽和吸着量からなるベクトル
Ａを Ａ＝（ａ1,−ａ2 ，−ａ3 ，・・・，−ａn+1 ）T ， （２）において得られた実数解の逆数を用いて得られる
（Ｐ＋１）×（ｎ＋１）の行列ＲをOf these values, the remaining time constant excluding the one with the largest absolute value (tau 1 ) is the time constant of each component gas. The vector A consisting of the saturated adsorption amount of each component gas is A = (a 1, −a 2 , −a 3 , ..., −a n + 1 ) T , the reciprocal of the real number solution obtained in (2) The matrix R of (P + 1) × (n + 1) obtained by using
【００３２】[0032]
【数６】 とすると、 （４）Ａ＝｛ＲT Ｒ｝-1ＲT Ｍより 各成分ガスの飽和吸着量ａj を求める。[Equation 6] Then, (4) the saturated adsorption amount a j of each component gas is obtained from A = {R T R} -1 R T M.
【００３３】以上のアルゴリズムにより得られた時定数
τj より各成分ガスの種類を同定する。すなわち、ある
時定数τj をガスｉの時定数τi と比較し（ステップ１
４）、τj がτi と等しくなければガスｉは判別されな
い（ステップ１６）。ステップ１４でτj がτi に等し
く、該混合ガス中にガスｉが含まれる可能性が大と判断
したのち、ａj がしきい値ｄi より大きいかどうかが判
断される（ステップ１５）。ｄi はａj がノイズによる
ものであるかどうか判断するための量であり、例えば予
め測定しておいた最小濃度の標準試料に対する飽和吸着
量とする。ａj≦ｄi の時、そのａj はノイズであると
判断されガスｉと判別されない（ステップ１６）。ａj
＞ｄi の時、ガスｉと判別し（ステップ１７）、その濃
度をａjから推定する（ステップ１８）。The type of each component gas is identified from the time constant τ j obtained by the above algorithm. That is, a certain time constant τ j is compared with the time constant τ i of gas i (step 1
4), if τ j is not equal to τ i , the gas i is not discriminated (step 16). After it is judged in step 14 that τ j is equal to τ i and the gas i is likely to be contained in the mixed gas, it is judged whether or not a j is larger than the threshold value d i (step 15). . d i is an amount for determining whether or not a j is due to noise, and is, for example, a saturated adsorption amount for a standard sample having a minimum concentration measured in advance. When a j ≤d i , the a j is judged to be noise and is not judged to be gas i (step 16). a j
When> d i , gas i is discriminated (step 17), and its concentration is estimated from a j (step 18).
【００３４】次に、この混合ガス成分判別および定量装
置の使用方法について説明する。Next, a method of using this mixed gas component discriminating and quantifying device will be described.
【００３５】まず、ガス供給器８から被検知ガスを含む
ガス試料を測定セル１内に送り出し、測定時間に比べ無
視できる時間内に測定セル１の内部の気体をガス試料で
置換する。すると、水晶発振子３の吸着膜２への被検知
ガス分子の吸着が開始し、この被検知ガスの吸着量の時
間変化は水晶発振子３の圧電応答に変換され、発振回路
４の発振周波数を周波数カウンタ５で計測することによ
って吸着量の時間変化をモニターできる。コンピュータ
６は一定時間ごとにカウンタ５の出力をサンプリング
し、水晶発振子３の圧電応答を追跡し、各成分ガスの時
定数τj 、飽和吸着量ａj を推定する。First, a gas sample containing a gas to be detected is sent into the measuring cell 1 from the gas supply device 8, and the gas inside the measuring cell 1 is replaced with the gas sample within a time that can be ignored compared to the measuring time. Then, the adsorption of the gas molecules to be detected to the adsorption film 2 of the crystal oscillator 3 is started, and the time change of the adsorption amount of the gas to be detected is converted into the piezoelectric response of the crystal oscillator 3, and the oscillation frequency of the oscillation circuit 4 is changed. The time change of the adsorption amount can be monitored by measuring with the frequency counter 5. The computer 6 samples the output of the counter 5 at regular intervals, traces the piezoelectric response of the crystal oscillator 3, and estimates the time constant τ j and the saturated adsorption amount a j of each component gas.
【００３６】その後コンピュータ６は標準試料に対して
行った測定から得られた時定数と比較することによって
各成分ガスの同定を行い、また、飽和吸着量から濃度の
定量を行って表示装置７に表示する。Thereafter, the computer 6 identifies each component gas by comparing it with the time constant obtained from the measurement performed on the standard sample, and also quantifies the concentration based on the saturated adsorption amount and displays it on the display device 7. indicate.
【００３７】次に、本実施例による混合ガス成分判別お
よび定量の具体例について説明する。Next, a specific example of the mixed gas component discrimination and quantification according to this embodiment will be described.
【００３８】図３は本実施例の混合ガス成分判別および
定量装置による水晶発振子３の圧電応答を示し、９４０
ｐｐｍのメタノ−ル（ａ）、１１１０ｐｐｍのベンゼン
（ｂ）、５８０ｐｐｍのアセトン（ｃ）および９４０ｐ
ｐｍのメタノールと１１１０ｐｐｍのベンゼンと５８０
ｐｐｍのアセトンの混合ガス（ｄ）に対する水晶発振子
３の圧電応答が周波数変化／時間曲線で示されている。FIG. 3 shows the piezoelectric response of the crystal oscillator 3 by the mixed gas component discriminating and quantifying device of this embodiment.
ppm methanol (a), 1110 ppm benzene (b), 580 ppm acetone (c) and 940 p
580 with pm methanol and 1110 ppm benzene
The piezoelectric response of the crystal oscillator 3 to a mixed gas (d) of ppm acetone is shown by a frequency change / time curve.
【００３９】ここで、コンピュータ６によるサンプリン
グ時間Δｔは４秒とした。吸着膜２は直径８０ｍｍのポ
リエチレン円盤を直径１３５ｍｍのポリテトラフロロエ
チレン円盤の上に乗せたものをターゲットとし、スパッ
タリングパワーは平均０．９４Ｗ／ｃｍ2 、スパッタリ
ング時間は７６分で作成し、その厚さは０．７６μｍで
ある。水晶発振子３はＡＴ−カットで厚さ０．１ｍｍ、
直径８５ｍｍの円盤である。Ｌ＝１５とし、混合ガス
（ｄ）から上述のアルゴリズムを用いて推定した時定数
と飽和吸着量を図４に示す。Here, the sampling time Δt by the computer 6 is set to 4 seconds. The adsorption film 2 was prepared by placing a polyethylene disk having a diameter of 80 mm on a polytetrafluoroethylene disk having a diameter of 135 mm, a sputtering power of 0.94 W / cm 2 on average, and a sputtering time of 76 minutes. The height is 0.76 μm. The crystal oscillator 3 is AT-cut and has a thickness of 0.1 mm.
It is a disk with a diameter of 85 mm. FIG. 4 shows the time constant and the saturated adsorption amount estimated from the mixed gas (d) by using the above algorithm with L = 15.
【００４０】図４のグラフにおいて、○印２１，２２，
２３はそれぞれメタノール（ａ）、ベンゼン（ｂ），ア
セトン（ｃ）の単独ガスに対する水晶発振子３の圧電応
答から得られた時定数および飽和吸着量である。また、
□印３１，３２，３３，３４はメタノール、アセトン、
ベンゼンの混合ガス（ｄ）に対する圧電応答から求めた
時定数および飽和吸着量である。混合ガス（ｄ）からは
４つの時定数が得られたが、その内の一つに対する飽和
吸着量３３は非常に小さく（０．７Ｈｚ）、これはノイ
ズによるものであると判断された。残りの３１，３２，
３４の３つはそれぞれ単独ガスの時定数に近く、この混
合ガスには上記メタノール、ベンゼン、アセトンの３つ
のガスが含まれていることがわかる。In the graph of FIG. 4, ◯ marks 21, 22,
23 is a time constant and a saturated adsorption amount obtained from the piezoelectric response of the crystal oscillator 3 with respect to a single gas of methanol (a), benzene (b), and acetone (c), respectively. Also,
□, 31, 32, 33, 34 are methanol, acetone,
The time constant and the saturated adsorption amount obtained from the piezoelectric response to the mixed gas (d) of benzene. Four time constants were obtained from the mixed gas (d), but the saturated adsorption amount 33 for one of them was very small (0.7 Hz), and it was judged that this was due to noise. The remaining 31, 32,
It can be seen that the three gas numbers 34 are close to the time constants of the individual gases, and that the mixed gas contains the three gases of methanol, benzene, and acetone.
【００４１】また、各成分ガスの飽和吸着量は単独ガス
の場合の飽和吸着量にほとんど等しいので、単独ガスの
場合の飽和吸着量−濃度の関係式から濃度の定量も可能
である。この場合、ガス（ａ），（ｂ），（ｃ）の飽和
吸着量はそれぞれ２５．８Ｈｚ、５５．１Ｈｚ、７４．
６Ｈｚであり、混合ガス（ｄ）中のメタノール、ベンゼ
ン、アセトンの飽和吸着量はそれぞれ２２．３Ｈｚ、４
５．７Ｈｚ、６１．３Ｈｚであって、各成分ガスの飽和
吸着量は単独ガスの場合の飽和吸着量にほとんど等しい
ので、単独ガスの場合の飽和吸着量−濃度の関係式から
濃度の定量も可能である。Further, since the saturated adsorption amount of each component gas is almost equal to the saturated adsorption amount in the case of a single gas, the concentration can be quantified from the saturated adsorption amount-concentration relational expression in the case of a single gas. In this case, the saturated adsorption amounts of the gases (a), (b) and (c) are 25.8 Hz, 55.1 Hz and 74.
6 Hz, and saturated adsorption amounts of methanol, benzene, and acetone in the mixed gas (d) are 22.3 Hz and 4 respectively.
At 5.7 Hz and 61.3 Hz, the saturated adsorption amount of each component gas is almost equal to the saturated adsorption amount in the case of a single gas, and therefore the concentration can be determined from the saturated adsorption amount-concentration relational expression in the case of a single gas. It is possible.
【００４２】本実施例の混合ガス成分判別および定量装
置では、一つの水晶発振子を用いて混合ガスに対する圧
電応答から得られる複数の時定数によって成分ガスの種
類を同定でき、また各成分ガスの飽和吸着量から濃度の
定量ができるので、コストが安くかつ正確な同定結果が
得られる。In the mixed gas component discriminating and quantifying apparatus of this embodiment, the type of the component gas can be identified by using a single crystal oscillator by a plurality of time constants obtained from the piezoelectric response to the mixed gas. Since the concentration can be quantified from the saturated adsorption amount, the cost is low and the accurate identification result can be obtained.
【００４３】[0043]
【発明の効果】以上説明したように本発明は、吸着膜を
表面に設けた単一の水晶発振子を用い、前記水晶発振子
をガス状の試料に曝し、前記水晶発振子の共振周波数の
時間変化から複数の時定数を抽出して各成分ガスの同定
を行い、各成分ガスの飽和吸着量から濃度の定量を行う
ので、従来困難であった混合ガス成分の同定と定量を安
価にかつ正確に行うことができるという効果がある。As described above, the present invention uses a single crystal oscillator provided with an adsorption film on its surface, exposes the crystal oscillator to a gaseous sample, and changes the resonance frequency of the crystal oscillator. Each component gas is identified by extracting multiple time constants from the time change, and the concentration is quantified from the saturated adsorption amount of each component gas. The effect is that it can be done accurately.
【図１】本発明の混合ガス成分判別および定量装置の一
実施例の構成ブロック図である。FIG. 1 is a configuration block diagram of an embodiment of a mixed gas component determination and quantification device of the present invention.
【図２】図１のコンピュータ６の処理のフローチャート
である。FIG. 2 is a flowchart of a process of a computer 6 of FIG.
【図３】図１の水晶発振子３の単独ガスおよび混合ガス
に対する圧電応答の一具体例を示すグラフである。FIG. 3 is a graph showing a specific example of piezoelectric response of the crystal oscillator 3 of FIG. 1 to a single gas and a mixed gas.
【図４】図３の圧電応答から得られた単独ガスおよび混
合ガスの時定数および飽和吸着量を示すグラフである。4 is a graph showing time constants and saturated adsorption amounts of a single gas and a mixed gas obtained from the piezoelectric response of FIG.
１ 測定セル ２ 吸着膜 ３ 水晶発振子 ４ 発振回路 ５ 周波数カウンタ ６ コンピュータ ７ 表示装置 １１，１２，・・・、１８ ステップ ２１，２２，２３ ○印 ３１，３２，３３，３４ □印 ａ ９４０ｐｐｍのメタノール ｂ １１１０ｐｐｍのベンゼン ｃ ５８０ｐｐｍのアセトン ｄ ９４０ｐｐｍのメタノール、１１１０ｐｐｍのベ
ンゼンおよび５８０ｐｐｍのアセトンの混合ガス1 Measuring cell 2 Adsorption film 3 Quartz oscillator 4 Oscillation circuit 5 Frequency counter 6 Computer 7 Display device 11, 12, ..., 18 Steps 21, 22, 23 ○ mark 31, 32, 33, 34 □ mark a of 940ppm Methanol b 1110 ppm benzene c 580 ppm acetone d 940 ppm methanol, 1110 ppm benzene and 580 ppm acetone mixed gas
Claims (4)
用い、被検知ガスの前記ガス吸着膜への吸着による前記
水晶発振子の共振周波数の変化を求めることにより混合
ガス中の各成分ガスの種類を同定し、かつ濃度を定量す
る混合ガス成分判別および定量方法において、 ガス吸着膜を表面に設けた一つの水晶発振子を用い、前
記水晶発振子の共振周波数の時間変化に含まれる指数関
数の時定数を検出する手順と、 前記手順により検出された水晶発振子の共振周波数の時
間変化に含まれる指数関数の時定数と、各成分ガスの単
独ガスの場合の共振周波数の時間変化を表わす指数関数
の時定数とを比較して一致するか否かにより、各成分ガ
スの種類の同定を行う手順と、 各成分ガスの前記ガス吸着膜への飽和吸着量を求めて各
成分ガスの濃度の定量を行う手順とを含むことを特徴と
する混合ガス成分判別および定量方法。1. A component in a mixed gas is obtained by using a crystal oscillator provided with a gas adsorption film on its surface, and obtaining a change in resonance frequency of the crystal oscillator due to adsorption of a gas to be detected to the gas adsorption film. In a mixed gas component identification and quantification method for identifying the type of gas and quantifying the concentration, a single crystal oscillator provided with a gas adsorption film on the surface is used, and the resonance frequency of the crystal oscillator is included in the time change. A procedure for detecting the time constant of the exponential function, the time constant of the exponential function included in the time change of the resonance frequency of the crystal oscillator detected by the procedure, and the time change of the resonance frequency in the case of a single gas of each component gas. Is compared with the time constant of the exponential function, and the procedure for identifying the type of each component gas is determined, and the saturated adsorption amount of each component gas to the gas adsorption film is calculated to determine each component gas. The concentration of A method for discriminating and quantifying a mixed gas component, which comprises a step of performing an amount.
まれる指数関数の時定数の検出に線型フィルタのアルゴ
リズムを用いたことを特徴とする請求項１記載の混合ガ
ス成分判別および定量方法。2. The method of discriminating and quantifying a mixed gas component according to claim 1, wherein a linear filter algorithm is used to detect the time constant of an exponential function included in the time change of the resonance frequency of the crystal oscillator.
晶発振子が配置された測定セルと、 前記測定セルにガス試料を供給するガス供給器と、 前記測定セルにガス試料が供給されたとき、前記水晶発
振子の共振周波数で発振する発振回路と、 前記発振回路が発振する水晶発振子の共振周波数をカウ
ントする周波数カウンタと、 表示装置と、 前記周波数カウンタでカウントされた、前記ガス試料の
ガス吸着膜への吸着による水晶発振子の共振周波数の時
間変化に含まれる指数関数の時定数を検出し、前記測定
セルに供給されたガス試料の各成分ガスの単独ガスの場
合の共振周波数の時間変化を表わす指数関数の時定数と
を比較して一致するか否かにより各成分ガスの種類の同
定を行い、かつ各成分ガスの前記吸着膜への飽和吸着量
を求めて各成分ガスの濃度の定量を行い、結果を前記表
示装置に表示するコンピュータとを有する混合ガス成分
判別および定量装置。3. A measurement cell in which a single crystal oscillator having a gas adsorption film provided on the surface thereof is arranged, a gas supplier for supplying a gas sample to the measurement cell, and a gas sample for supply to the measurement cell. An oscillation circuit that oscillates at the resonance frequency of the crystal oscillator, a frequency counter that counts the resonance frequency of the crystal oscillator that the oscillation circuit oscillates, a display device, the frequency counter, In the case of a single gas of each component gas of the gas sample supplied to the measurement cell, the time constant of the exponential function included in the time change of the resonance frequency of the crystal oscillator due to the adsorption of the gas sample to the gas adsorption film is detected. The type of each component gas is identified by comparing with the time constant of the exponential function that represents the time change of the resonance frequency, and it is determined whether the saturated adsorption amount of each component gas to the adsorption film is obtained. Perform quantification of the concentration of the minute gas, mixed gas component and a computer for displaying the result on the display device determination and quantification device.
の含弗素系高分子薄膜が用いられたことを特徴とする請
求項３記載の混合ガス成分判別および定量装置。4. The mixed gas component discriminating and quantifying device according to claim 3, wherein a fluorine-containing polymer thin film derived from plasma is used for the gas adsorption film of the crystal oscillator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05099696A JP3141969B2 (en) | 1993-04-26 | 1993-04-26 | Method and apparatus for determining and quantifying mixed gas components |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05099696A JP3141969B2 (en) | 1993-04-26 | 1993-04-26 | Method and apparatus for determining and quantifying mixed gas components |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06308008A true JPH06308008A (en) | 1994-11-04 |
| JP3141969B2 JP3141969B2 (en) | 2001-03-07 |
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ID=14254218
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05099696A Expired - Lifetime JP3141969B2 (en) | 1993-04-26 | 1993-04-26 | Method and apparatus for determining and quantifying mixed gas components |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5817921A (en) * | 1996-07-12 | 1998-10-06 | Advanced Technology Materials, Inc. | Piezoelectric enviromental fluid monitoring assembly and method |
| US6029500A (en) * | 1998-05-19 | 2000-02-29 | Advanced Technology Materials, Inc. | Piezoelectric quartz crystal hydrogen sensor, and hydrogen sensing method utilizing same |
| US6079252A (en) * | 1998-05-20 | 2000-06-27 | Advanced Technology Materials, Inc. | Leak detection device, and fluid vessel assembly comprising same |
| CN1070266C (en) * | 1994-09-20 | 2001-08-29 | 株式会社日立制作所 | Scroll type fluid machine |
| US6295861B1 (en) | 1999-01-28 | 2001-10-02 | Advanced Technology Materials, Inc. | Quartz crystal microbalance sensors and semiconductor manufacturing process systems comprising same |
| JP2002350313A (en) * | 2001-05-25 | 2002-12-04 | Mitsubishi Electric Corp | Method and device for chemicals quantification |
| JP2010071716A (en) * | 2008-09-17 | 2010-04-02 | Seiko Epson Corp | Qcm device and method for manufacturing the same |
| WO2020026328A1 (en) * | 2018-07-31 | 2020-02-06 | 日本電気株式会社 | Information processing device, control method, and program |
-
1993
- 1993-04-26 JP JP05099696A patent/JP3141969B2/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1070266C (en) * | 1994-09-20 | 2001-08-29 | 株式会社日立制作所 | Scroll type fluid machine |
| US5817921A (en) * | 1996-07-12 | 1998-10-06 | Advanced Technology Materials, Inc. | Piezoelectric enviromental fluid monitoring assembly and method |
| US6029500A (en) * | 1998-05-19 | 2000-02-29 | Advanced Technology Materials, Inc. | Piezoelectric quartz crystal hydrogen sensor, and hydrogen sensing method utilizing same |
| US6079252A (en) * | 1998-05-20 | 2000-06-27 | Advanced Technology Materials, Inc. | Leak detection device, and fluid vessel assembly comprising same |
| US6295861B1 (en) | 1999-01-28 | 2001-10-02 | Advanced Technology Materials, Inc. | Quartz crystal microbalance sensors and semiconductor manufacturing process systems comprising same |
| JP2002350313A (en) * | 2001-05-25 | 2002-12-04 | Mitsubishi Electric Corp | Method and device for chemicals quantification |
| JP2010071716A (en) * | 2008-09-17 | 2010-04-02 | Seiko Epson Corp | Qcm device and method for manufacturing the same |
| WO2020026328A1 (en) * | 2018-07-31 | 2020-02-06 | 日本電気株式会社 | Information processing device, control method, and program |
| JPWO2020026328A1 (en) * | 2018-07-31 | 2021-08-02 | 日本電気株式会社 | Information processing equipment, control methods, and programs |
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| Publication number | Publication date |
|---|---|
| JP3141969B2 (en) | 2001-03-07 |
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