JPS60198446A - Gas detector - Google Patents
Gas detectorInfo
- Publication number
- JPS60198446A JPS60198446A JP5426684A JP5426684A JPS60198446A JP S60198446 A JPS60198446 A JP S60198446A JP 5426684 A JP5426684 A JP 5426684A JP 5426684 A JP5426684 A JP 5426684A JP S60198446 A JPS60198446 A JP S60198446A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- gas detection
- spectrum
- detection
- temperature
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0031—General constructional details of gas analysers, e.g. portable test equipment concerning the detector comprising two or more sensors, e.g. a sensor array
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Physics & Mathematics (AREA)
- Combustion & Propulsion (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Measurement Of Resistance Or Impedance (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は半導体ガス検出素子、及び記憶手段を有する演
算装置を設けて、ガスの種類及び濃度を検出する装置に
関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an apparatus for detecting the type and concentration of gas by providing a semiconductor gas detection element and an arithmetic unit having a storage means.
従来、酸化スズ（５ＦＬＯ２）、酸化亜鉛（ＺｒＬＯ）
、酸化鉄（Ｆｅ２ｅｓ ）などの半導体ガス検出素子は
、加熱により活性化された状態での素子導電率がガス濃
度によって特定な変化を示す特徴を有するため実用的測
定に耐える機能をもち、また使い易く安価なこともあっ
て多く用いられてきた。Conventionally, tin oxide (5FLO2), zinc oxide (ZrLO)
Semiconductor gas detection elements such as iron oxide (Fe2es) have the characteristic that the element conductivity changes in a specific manner depending on the gas concentration when activated by heating, so they have the ability to withstand practical measurements and are easy to use. It has been widely used because it is easy and inexpensive.
ところが、−上記した一般的なガス検出素子が特定ガス
にだけ選択的な感度をもつことはほとんどなく、ガス種
によって異なる検出特性を有することが通常であるため
、既定のガスだけを画一的に検知する能力しかない。ま
た、温度、湿度等の雰囲気条件にも大きく影響を受ける
。However, - the above-mentioned general gas detection elements rarely have selective sensitivity only to a specific gas, and usually have different detection characteristics depending on the gas type. only has the ability to detect it. It is also greatly affected by atmospheric conditions such as temperature and humidity.
そとで、ガス種の識別、定量を実現する次のような方法
、装置が提案されている。例えば、特開昭５Ｏ−８０Ｈ
＋２ Ｊガス検知素子」には、αなるガスの検知を目的
とするがガスαを選択的に検知できる素子が無い場合に
、ガスαおよびｂを検知できる索子Ｓａｂと、ガスｂだ
けを選択的に検知する素子ｓｂとを備え、Ｓａｂが何ら
かのガスを検知した際にＳ１５のガスｂ検知を確認する
ことでガスαの有無を識別する方法が開示されている。Therefore, the following methods and devices have been proposed for identifying and quantifying gas types. For example, JP-A-5O-80H
+2 J Gas Detection Element", the purpose is to detect gas α, but if there is no element that can selectively detect gas α, select only the probe Sab that can detect gases α and b, and gas b. A method is disclosed in which the presence or absence of gas α is identified by confirming the detection of gas b in S15 when Sab detects some gas.
また、特開昭５１ ９Ｆ１９８ （’ガス検出装置」に
は、ガス検知素子を一定の高温度に保持した高温部とそ
れより低温に保持された低温部の２部に分けて構成し、
これら各部の抵抗値の比からガス種の識別を妨害ガスに
影響されずに実施する装置が開示しである。さらに、特
開昭５１−８０２９３ ［ガス検出装置−１には、並列
に一対設けた同−索子の加熱温度を、雰囲気中の感知ガ
スのうちの特定な被検知ガスだけの感度の傾向が逆にな
るような２つの温度域に設定し、これらの抵抗の変化量
の差から上記の特定検知ガスを選択的に検出する装置が
開示されている。In addition, Japanese Patent Application Laid-Open No. 51-9F198 ('Gas detection device' has a configuration in which the gas detection element is divided into two parts: a high temperature part that is kept at a constant high temperature and a low temperature part that is kept at a lower temperature,
An apparatus is disclosed that identifies the gas type from the ratio of the resistance values of these parts without being affected by interfering gas. Furthermore, in JP-A-51-80293 [Gas Detection Device-1, the heating temperature of a pair of cables installed in parallel can be adjusted to determine the sensitivity tendency of only a specific gas to be detected among the sensed gases in the atmosphere. An apparatus has been disclosed that sets two temperature ranges that are opposite to each other and selectively detects the above-mentioned specific detection gas based on the difference in the amount of change in these resistances.
しかしながら、上述した３件の例か、もしくはそれらに
類似する方法、装置に次のような欠点がある。まず第１
は、検出対象とできる２種のガスの組合せが犬きく制約
されることである。However, the three examples mentioned above, or methods and devices similar to them, have the following drawbacks. First of all
The problem is that the combinations of two gases that can be detected are severely restricted.
なぜなら、組合わせる被検知ガスに対して、所望通りの
選択的検出あるいは感度傾向の逆転を実現する素子を意
図的に構成することが技術的に非常に難しいからである
。また第２は、上記の所望通りの素子が実現できたとし
ても、これらの特性が現われる２種のガスの組合わせが
一組だけであるとは限らない場合が多く、結果的には厳
密なガス種識別は不可能だからである。This is because it is technically very difficult to intentionally construct an element that achieves desired selective detection or reversal of sensitivity trends for the combination of gases to be detected. Second, even if the desired device described above can be realized, there are many cases where there is not only one combination of two gases that exhibit these characteristics, and as a result, it is not possible to strictly This is because gas type identification is impossible.
さらに第３は、上述のように２個の素子あるいは２種の
加熱温度だけでのガス種識別が技術的に実現不可能であ
る場合に、前記の例に示した方法に従ってその対応策が
構成される限り、素子数あるいは加熱温度の種類を増加
させる方向の対策となり、これは装置構成の複雑化と、
素子出力の処理過程の煩雑化を招来し、高い価格性能比
が期待でき々くなるためである。Third, if it is technically impossible to identify the gas type using only two elements or two types of heating temperatures as described above, a countermeasure can be constructed according to the method shown in the example above. As long as the
This is because the process of processing the element output becomes complicated, making it difficult to expect a high price/performance ratio.
本発明は上述の事情に鑑みて為さｈたもので、その目的
とするところは、小数のガス検出素子を設けて多種類の
特定ガス、混合ガス、成分ガスの種類及び濃度を検出１
〜得る小形、低価格のガス検出装置を提供しようとする
ものである。The present invention has been made in view of the above-mentioned circumstances, and its purpose is to detect the types and concentrations of many types of specific gases, mixed gases, and component gases by providing a small number of gas detection elements.
The present invention aims to provide a small, low-cost gas detection device that achieves the following.
本発明の要点は、多様なガスに反応するとともにガス感
度がガス種に応じて相異なるというごく一般的々特性を
有するガス検出素子な適数個具備し、これらの素子の活
性状態を加熱温度によって適宜ｌこ制御することで特異
的に変動するガス検出出力の様態を一種のスペクトルパ
ターンと解釈し、これをよく知られたパターン認識手法
に従ってあらかじめ測定しである標準的なガスに対する
スペクトルとの類似性を分析することで、具備する素子
数を大幅に上回る多種類のガスに関するガス情報の検出
を実現せしめた点にある。The key point of the present invention is to provide an appropriate number of gas detection elements having very general characteristics such as reacting to various gases and having different gas sensitivities depending on the gas type, and to control the activation state of these elements by heating temperature. By controlling the gas detection output as appropriate, the manner in which the gas detection output varies specifically is interpreted as a kind of spectral pattern, and this is compared with the spectrum for a standard gas measured in advance according to a well-known pattern recognition method. By analyzing the similarities, it has been possible to detect gas information about a wide variety of gases, far exceeding the number of elements included.
一般に、半導体ガス検出素子のガスに対する感度は、下
記（１）〜（６）に示すようにガス自体の化学的性質に
より相異なり、また（４）〜（７）のように素子の加熱
温度によっても相異なることが知られている。In general, the sensitivity of a semiconductor gas detection element to gas varies depending on the chemical properties of the gas itself, as shown in (1) to (6) below, and also depends on the heating temperature of the element, as shown in (4) to (7). It is also known that they are different.
（１）水素、エチレン系炭化水素等の吸着力が大きなガ
スには感度が高い。(1) High sensitivity for gases with large adsorption power such as hydrogen and ethylene hydrocarbons.
（２）有機鎖状分子構造を有し、炭素数が多くかつ不飽
和度が大である炭化水素には高感度である。(2) It is highly sensitive to hydrocarbons that have an organic chain molecular structure, a large number of carbon atoms, and a high degree of unsaturation.
（′５） アミン、エーテル、メルカプタン、アルニー
ル、ケトン、アルデヒド、カルボン酸、の順で活性な電
子供与性の官能基を有するガスに感度が高い。('5) High sensitivity to gases having active electron-donating functional groups in the order of amines, ethers, mercaptans, alnyls, ketones, aldehydes, and carboxylic acids.
（４）素子表面が高温であるほど近傍のガスが活性化さ
れ吸着量が増加するため感度が高くなる。しかｌ−１あ
る程度の温度以上では、ガス分子の脱離速度が速や過ぎ
るため吸着量が低下するため感度がさがる。(4) The higher the temperature of the element surface is, the more nearby gases are activated and the amount of adsorption increases, resulting in higher sensitivity. However, above a certain temperature of 1-1, the rate of desorption of gas molecules is too rapid and the amount of adsorption decreases, resulting in a decrease in sensitivity.
（５） 素子温度により表面に吸着する酸素イオンの種
類が異なるため、素子導電率の変化が吸着酸素をガス分
子が引き抜く（ガス分子と吸着酸素が交替する）ことで
起こる電子移動によって発生する場合は、素子温度に従
って感度が変化する。(5) Since the type of oxygen ions adsorbed on the surface differs depending on the element temperature, changes in element conductivity occur due to electron transfer caused by gas molecules pulling out adsorbed oxygen (gas molecules and adsorbed oxygen exchange). The sensitivity changes according to the element temperature.
（６）上記（５）の場合、表面温度が高いほどガス分子
の酸化活性（吸着酸素を引き抜く性質）が増加するため
高感度化する。(6) In the case of (5) above, the higher the surface temperature, the higher the oxidation activity of gas molecules (the ability to extract adsorbed oxygen), resulting in higher sensitivity.
（７）素子が基本母材に触媒添加したものの場合、触媒
が高次酸化状態から低次酸化状態に移行する際に生成さ
れるガス分子の酸化反応中間体が、母材上の吸着酸素を
引き抜くことで素子導電率が変化する。このとき、素子
温度が高いほど反応中間体が増加するため高感度となる
。しかし、ある程度の温度以上では、触媒上での酸化反
応が優先され母材表面の吸着酸素を引き抜く反応中間体
が減少するため感度が低下する。(7) If the element is one in which a catalyst is added to the basic base material, the oxidation reaction intermediate of gas molecules produced when the catalyst transitions from a higher oxidation state to a lower oxidation state absorbs the adsorbed oxygen on the base material. By pulling out the element conductivity changes. At this time, the higher the element temperature is, the more reaction intermediates are produced, resulting in higher sensitivity. However, above a certain temperature, the oxidation reaction on the catalyst takes precedence and the number of reaction intermediates that extract oxygen adsorbed on the surface of the base material decreases, resulting in a decrease in sensitivity.
このように、添加触媒、加熱条件、等の検討により、あ
る限られたガス種にだけ選択的に感度をもつ検出素子を
実現することは、技術的に容易であると考えられる。し
かし、このような素子の開発には慎重な実験計画と美大
な実験量が必要である。In this way, it is considered to be technically easy to realize a detection element that is selectively sensitive only to a certain limited type of gas by examining the added catalyst, heating conditions, and the like. However, the development of such devices requires careful experimental planning and a large amount of experimentation.
そこで、上述した半導体ガス検出素子の一般的性質を積
極的に利用することで、単一の素子もしくは最小眼側の
素子を用いた特殊仕様の検出素子を必要としない選択的
なガス情報の検出を実現して前述の目的（多種数のガス
の種類。Therefore, by proactively utilizing the general properties of the semiconductor gas detection element described above, selective gas information detection using a single element or an element on the smallest eye side does not require a specially designed detection element. To achieve the aforementioned objectives (a wide variety of gas types).
濃度を検出できる小形、低価格のガス検出装置）を達成
する為、本出願の第１の発明は１個の半導体ガス検出素
子と、上記１個のガス検出素子の温度を制御する手段と
、上記１個のガス検出素子の検出出力信号を演算する装
置とを設けて、前記１個のガス検出素子の検出スペクト
ルを算出し得るように構成し、かつ、上記演算装置は記
憶手段を備えたものとして複数種類のガスの各種濃度に
対応する標準スペクトルを記憶せしめ、前記の算出した
スペクトルと記憶［７ているスペクトルとを比較して検
出ガスの種類及び濃度を算出できるように構成したこと
を特徴とする０
また、前記と同一の目的を達成するため本出願の第２の
発明は、互いにガス検出特性を異にする複数個の半導体
ガス検出素子と、上記複数個のガス検出素子の温度を制
御する手段と、上記複数個のガス検出素子の検出出力信
号を演算する装置とを設けて、該複数個のガス検出素子
の検出スペクトルを算出し得るように構成し、かつ、上
記演算装置は記憶手段を備えたものとして複数種類のガ
スの各種濃度に対応する標準スペクトルを記憶せしめ、
前記の算出したスペクトルと記憶しているスペクトルと
を比較して検出ガスの種類及び濃度を算出できるように
構成したことを特徴とする。In order to achieve a small, low-cost gas detection device capable of detecting concentration, the first invention of the present application includes one semiconductor gas detection element, means for controlling the temperature of the one gas detection element, A device for calculating a detection output signal of the one gas detection element is provided so as to be able to calculate a detection spectrum of the one gas detection element, and the calculation device is provided with a storage means. Standard spectra corresponding to various concentrations of multiple types of gases are stored, and the type and concentration of the detected gas can be calculated by comparing the calculated spectra with the stored spectra. Further, in order to achieve the same object as the above, a second invention of the present application includes a plurality of semiconductor gas detection elements having mutually different gas detection characteristics, and a temperature control system of the plurality of gas detection elements. and a device for calculating the detection output signals of the plurality of gas detection elements, and configured to be able to calculate the detection spectra of the plurality of gas detection elements, and the calculation device is equipped with a storage means and stores standard spectra corresponding to various concentrations of multiple types of gases,
The present invention is characterized in that it is configured such that the type and concentration of the detected gas can be calculated by comparing the calculated spectrum with the stored spectrum.
以下、本発明にかかるガス検出装置の実施例について図
面を用いて詳細に説明する。Embodiments of the gas detection device according to the present invention will be described in detail below with reference to the drawings.
本実施例においては、前記の互いにガス検出特性を異に
する複数個の半導体ガス検出素子として、ＷＯ３検出素
子と５ｎ０２検出素子とを用いた。In this example, a WO3 detection element and a 5n02 detection element were used as the plurality of semiconductor gas detection elements having mutually different gas detection characteristics.
次に、これら検出素子の構成と特性とについて述べる。Next, the configuration and characteristics of these detection elements will be described.
（ｌ −ａ ） Ｗ０５ペーストの作製粒径１μｍ以下
に粉砕した純度９９９９％のＷＯｓ粉末１ａ、ｆ ｌｃ
、Ｐｅｔ粉末０．２ｆとバインダガラス２２と１０
ｃｐｓエチルセルロースの９％トリテカ／ −ル溶液７
ｃｃとを加えて混練して感ガスペーストとなす。(l-a) Preparation of W05 paste 9999% pure WOs powder 1a, f lc crushed to a particle size of 1 μm or less
, Pet powder 0.2f and binder glass 22 and 10
9% tritecarol solution of cps ethyl cellulose 7
cc and knead to form a gas-sensitive paste.
（ｉ−ｂ）ＷＯ３検出素子の構成
上述のＷＯｘペーストを使用して構成したガス検出素子
の概略構造図を第１図に示す。同図（ａ）は平面図、同
図（ｂ）は裏面図、同図（Ｃ）は同図（ａ）のＡＡ’断
面図である。同図（ａ）に示すように基板上にＷ０５ペ
ーストを使用した検出素子１１が配置されている。構成
順序を説明すると、耐熱絶縁基板１２上に金導体ペース
ト（たとえばデュポン社製／１６８７６０ペースト）を
用いて下部電極１３、接続導体１６１をよく知られた厚
膜印刷技術を用いて所定の位置に形成し、乾燥する。ま
た同時に、第１図（ｂ）に示すように１２の裏面に金導
体ペースト（同Ａ３７（Ｓｏ）を用いて加熱用ヒータの
パターン１４を形成し乾燥する。これを焼成温度１２０
０℃、保持時間２時間で焼成して検出素子用基板を準備
する。つぎに、Ｗ０３ペースト１５を１３ 、１４と同
様の厚膜技術によって所定の位置ζこ形成し、これを乾
燥した後に金導体ペースト（同Ａ ８７６０ ）を用い
て上部電極１６、接続導体１６１を所定の形状に印刷形
成し乾燥する。これを焼成温度９００℃、保持時間１０
分で焼成１−て、サンドイッチ構造の検出素子が完成す
る。(ib) Structure of WO3 Detection Element FIG. 1 shows a schematic structural diagram of a gas detection element constructed using the above-mentioned WOx paste. 3A is a plan view, FIG. 2B is a back view, and FIG. As shown in FIG. 5A, a detection element 11 using W05 paste is arranged on a substrate. To explain the construction sequence, the lower electrode 13 and the connecting conductor 161 are placed in predetermined positions on the heat-resistant insulating substrate 12 using a gold conductor paste (for example, DuPont/168760 paste) using a well-known thick film printing technique. Form and dry. At the same time, as shown in FIG. 1(b), a pattern 14 of a heating heater is formed on the back surface of 12 using gold conductor paste (A37 (So)) and dried.
A detection element substrate is prepared by baking at 0° C. for 2 hours. Next, W03 paste 15 is formed at predetermined positions using the same thick film technique as 13 and 14, and after this is dried, upper electrode 16 and connection conductor 161 are formed at predetermined positions using gold conductor paste (A 8760). Print it into the shape and dry it. This was fired at a temperature of 900°C and a holding time of 10
After baking for 1 minute, a sandwich-structured detection element is completed.
（ｉ −ｃ ） ＷＯｓ検出素子の温度特性上述のよう
に検出素子の裏面には加熱用ヒータが設けてあり、この
ヒータに加える電圧と素子温度との関係を第２図に示す
。本図のように電圧−素子温度特性は非線形である。し
かし、ヒータ電圧値のＮ個の数列＝（ｎ） （ｒＬ”１
，２．−、Ｎ ）を考え、これらの素子温度特性が線形
となるよりなＮおよび−（−）を決定することは容易で
ある。(i-c) Temperature characteristics of the WOs detection element As mentioned above, a heater is provided on the back surface of the detection element, and FIG. 2 shows the relationship between the voltage applied to this heater and the element temperature. As shown in this figure, the voltage-device temperature characteristics are nonlinear. However, N sequences of heater voltage values = (n) (rL”1
,2. -, N), it is easy to determine N and -(-) at which the temperature characteristics of these elements become linear.
このときの素子温度Ｔ（ｙｚ）は、設定する素子温度の
最高値をＴｌｌ１ｇ、最低値Ｔｍｍとすると決起（１）
式で与えられ、その特性は第６図のようになる。The element temperature T(yz) at this time is determined by (1), assuming that the maximum value of the element temperature to be set is Tll1g and the minimum value Tmm.
It is given by the formula, and its characteristics are shown in FIG.
Ｔ（月＝ ］＝ｆ（ＴＭ−Ｔｍｉ） ＋Ｔｍ１ｎ、（ｎ
＝１．２．−、Ｎ）・・・ （１）
す々わち、上記のＮ１−（ｙｂｌをあらかじめ測定して
おき、この−（−）をＤ／Ａ変換器によって発生できる
ようなＮ個のディジタル信号を決定しておけば、これら
を記憶したマイクロプロセッサによって素子温度を自由
に制御できるのである。T(Month= ]=f(TM-Tmi) +Tm1n, (n
=1.2. -, N)... (1) In other words, measure the above N1-(ybl) in advance, and generate N digital signals that can generate this -(-) with a D/A converter. Once determined, the element temperature can be freely controlled by the microprocessor that stores these values.
また言うまでもなく、特に上述のような線形特性が必要
であるということではなく、非線形でも構わないし、逆
に後述するスペクトルの特異性を強調する目的で、意図
的に非線形特性を与える数列−（、）（すなわち温度上
昇プロフィール）を設定することも考えられる。Needless to say, the above-mentioned linear characteristics are not particularly necessary; non-linear characteristics are also acceptable; on the contrary, in order to emphasize the specificity of the spectrum, which will be described later, a sequence of numbers intentionally giving non-linear characteristics -(, ) (i.e., a temperature rise profile).
（ｉ −ｄ ） ＷＯ５検出素子のガス検出特性前述の
ように構成１−た素子のガス検出特性を第４図に示す。(i-d) Gas detection characteristics of the WO5 detection element The gas detection characteristics of the element constructed as described above are shown in FIG.
本図から、メタンに感度が無いこと、水素およびアルコ
ールのスペクトルは類似しており低温であるほど高感度
化すること、−酸化炭素あるいはプロパンのスペクトル
にはピークが発生するがピーク温度は異なることなどが
わかる。すなわち、ＷＯ３累子−９だけでもその素子温
度に対する出カスベクトルを詳細に分析することにより
、正確なガス種識別が可能となるのである。From this figure, we can see that there is no sensitivity to methane, that the spectra of hydrogen and alcohol are similar, and the lower the temperature, the higher the sensitivity becomes; - Although a peak occurs in the spectrum of carbon oxide or propane, the peak temperature is different. etc. can be understood. In other words, by analyzing in detail the output vector with respect to the element temperature of only the WO3 component-9, it is possible to accurately identify the gas type.
（Ｉｆ ａ ） ５ｎ０２ペースト、検出素子１７）
作製純度９９．９９％の金属スズＳｎを濃硝酸で処理し
、水洗後スズ酸の白色沈澱物を蒸発・乾固し、粉砕後７
００℃の空気中で焙焼して５ＴＬＯ２粉末となし、この
粉末にＰｄＣｌ２水溶液を加え混練して５ｎ０２・１
％ Ｐｄ混合の粉末を得る。この粉末１０９に有機ビヒ
クル６ｃｃとＳｉ −Ｐｄ−ＺｒＬ−Ｔｉ系結晶化ガラ
スを約１” ｗｔ％加えて混練し、５ｒＬ０２ペースト
となす。(If a) 5n02 paste, detection element 17)
Preparation Metallic tin with a purity of 99.99% was treated with concentrated nitric acid, and after washing with water, the white precipitate of stannic acid was evaporated to dryness.
Roast in air at 00℃ to obtain 5TLO2 powder, add PdCl2 aqueous solution to this powder and knead to obtain 5n02.1
% Pd mixed powder is obtained. To this powder 109, 6 cc of organic vehicle and about 1'' wt% of Si-Pd-ZrL-Ti crystallized glass were added and kneaded to form a 5rL02 paste.
このペーストを使用し、前述のＷＯ５ペーストに対する
と同様の方法をもってＳｎＯ２検出素子を得る。この素
子は第１図と同様の概略構造を有する。また素子温度に
ついても第２．３図と同様である。Using this paste, a SnO2 detection element is obtained in the same manner as for the WO5 paste described above. This element has a general structure similar to that in FIG. Further, the element temperature is also the same as that shown in Fig. 2.3.
（ＩＩ １） ） ８ｎＯ２検出素子のガス検出特性上
述のように構成した５ｒＬＯ２素子のガス検出特性を第
５図に示す。本図から、−酸化炭素とメタンのスペクト
ルは同方向に凸であり特に−酸化炭素には約４５０℃以
上で感度がなくなること、水素では線形に近いこと、プ
ロパンとアルコールのスペクトルは一酸化炭素とメタン
とは逆の方向に凸であり、アルコールにはピークが存在
すること、などがわかる。なお、第４．５図に示した特
性の測定方法を説明すると、まず７００℃を目標に加熱
（１分間）し素子表面の吸着水を除いた上で３００℃ま
で自然冷却する （この間１分）、この状態から所定の
電圧を逐次ヒータに加えていき電圧変更から温度整定時
間（約５秒）だけ遅延させて素子出力を測定するのであ
る。(II 1)) Gas Detection Characteristics of 8nO2 Detection Element The gas detection characteristics of the 5rLO2 element constructed as described above are shown in FIG. From this figure, we can see that - the spectra of carbon oxide and methane are convex in the same direction; in particular - that sensitivity disappears for carbon oxide above about 450°C; for hydrogen, it is nearly linear; and that the spectra of propane and alcohol are convex in the same direction. It can be seen that the curve is convex in the opposite direction to that of methane, and that alcohol has a peak. To explain how to measure the characteristics shown in Figure 4.5, first heat the element to a target temperature of 700°C (for 1 minute), remove the adsorbed water on the element surface, and then naturally cool it to 300°C (during this time for 1 minute). ), from this state, a predetermined voltage is sequentially applied to the heater, and the element output is measured with a delay of temperature settling time (about 5 seconds) after the voltage change.
また、第５図のようなスペクトルだけではなく第６，７
図のような濃度特性も測定しておかなければならない。Also, not only the spectrum shown in Fig. 5 but also the 6th and 7th spectra.
The concentration characteristics shown in the figure must also be measured.
ここではその代表として、素子温度３５ Ｄ’Ｃのとき
の一酸化炭素濃度特性を第６図に、素子温度５５０℃の
メタン濃度特性を第７図に示す。すなわち、検知ガスに
対してもつとも感度が高くなる素子温度における素子出
力から当該ガス濃度をめるのである。Here, as representative examples, the carbon monoxide concentration characteristics when the element temperature is 35 D'C are shown in FIG. 6, and the methane concentration characteristics when the element temperature is 550 DEG C. are shown in FIG. In other words, the gas concentration is determined from the element output at the element temperature at which the sensitivity to the detected gas becomes higher.
次に、前記の５ｎ０２ガス検出素子８１を用いて構成し
たガス検出装置の１実施例を第８図に示す。Next, FIG. 8 shows an embodiment of a gas detection device constructed using the 5n02 gas detection element 81 described above.
（１） ガス検出素子８１の温度をＴｍに設定して所定
時間保持Ｉ−１素子表面の吸着水を除去する。この後、
温度がＴ１ｎＩＩ＋となるまで自然冷却する。（ｎ ＝
１とする）
（Ｉｌｌ ａｌの素子温度をＴ（ｎ、）に制御する。つ
まり、マイクロブロセツｖ８２からのディジタル制御信
号ルをＤ／Ａ変換器８３によって変換してＶ（ル）を得
て、これを電圧フォロワ８４によって負荷駆動能力を整
合した上でヒータ８５に加え素子温度Ｔ（ル）とする。(1) The temperature of the gas detection element 81 is set to Tm and held for a predetermined time to remove adsorbed water on the surface of the I-1 element. After this,
Cool naturally until the temperature reaches T1nII+. (n =
1) (The element temperature of Ill al is controlled to T(n,). In other words, the digital control signal from the microprocessor v82 is converted by the D/A converter 83 to obtain V(l). , after matching the load driving ability with the voltage follower 84, it is added to the heater 85 to set the element temperature T.
（ｌｉｏ ８１の素子出力を測定する。つまシ、ガス検
知による素子の導電率変化を、測定用電圧Ｖ５の直列抵
抗８６での降下値に置換し、これをオペアンプ８７によ
って適宜に増巾してアナログ電圧Ｖｙとし、Ａ／Ｄ変換
器８８でディジタル信号Ｖ”（１Ｌ）に変換し８２に記
憶する。(Measure the element output of LIO 81.) Replace the change in conductivity of the element due to gas detection with the drop value of the measurement voltage V5 across the series resistor 86, and amplify this appropriately with the operational amplifier 87. The analog voltage Vy is converted into a digital signal V'' (1L) by an A/D converter 88 and stored in 82.
（ＩＶ）ル＝Ｎでなければ（１１）へ戻る。(IV) If Le=N, return to (11).
（Ｖ）測定データ列Ｖ”（ｙＬ）を（２）式に従って正
準化し、検出スペクトル■（ル）となす。(V) The measured data sequence V" (yL) is canonicalized according to equation (2) to form a detected spectrum (2).
〜Ｉ）正準化したスペクトル■（ル）とあらかじめ記憶
しである標準ガスに対するスペクトルＰ（ル）とを、パ
ターン認識手法によって逐次比較しガス種を識別する。~I) The canonical spectrum (1) and the pre-stored spectrum P (2) for a standard gas are successively compared using a pattern recognition technique to identify the gas type.
ここで、パターン認識手法とは２つのスペクトルの類似
度Ｊを算出評価することに他ならない。この類似度ｄは
、連続系で表現すれば温度ｔをパラメータとする２つの
スペクトルＶ（ｔ） 。Here, the pattern recognition method is nothing but calculating and evaluating the similarity J between two spectra. This degree of similarity d is expressed in a continuous system as two spectra V(t) with temperature t as a parameter.
Ｐ（ｔ）に対する（６）式のような積分となる。また、
本実施例のような離散系で表現すればｄ ＝Ｊ””、
（Ｖ（ｔ） −Ｐ（ｔ））ｄｔ ９１１１．−１（３１
Ｔ順
（４）式のような差分となる。さらに、ヒータｃｔ＝
ｘ （Ｖ（ｎｌ −ＰＬ＋ｚｌ Ｊ ＝・（４１ｎ＝１
電圧−素子温度間の非線形特性を反映させ’＝ｒＬ：２
２（（Ｖ（ル） Ｐ（’ｌ）＋（Ｖ（ｎ−１−Ｐ（Ｗ−
旬））Ｘ（Ｔ（ｎｌ−Ｔ（ｔＬ−１）） −・・−（５
するならば（５）式が妥当と考えられる。This results in an integral such as equation (6) for P(t). Also,
If expressed in a discrete system like this example, d = J"",
(V(t) −P(t))dt 9111. -1(31
The difference is as shown in equation (4) in T order. Furthermore, heater ct=
x (V(nl −PL+zl J =・(41n=1 Reflecting the nonlinear characteristics between voltage and element temperature'=rL:2
2((V(ru) P('l)+(V(n-1-P(W-
season))X(T(nl-T(tL-1)) -...-(5
If so, equation (5) is considered to be valid.
（ｖｌｌ）識別したガス種にもりとも高感度となる素子
温度に対応する測定データイ（ル）からガス濃度を定量
する。ここで、定量用のデータはあらかじめ（６）式に
示すような離散値の索引テーブルとして記憶されている
。Ｃｉは測定データＶ’２に対する濃度、 Ｍはデータ
。(vll) Quantify the gas concentration from the measurement data file corresponding to the element temperature that is highly sensitive to the identified gas type. Here, the quantitative data is stored in advance as an index table of discrete values as shown in equation (6). Ci is the concentration for the measurement data V'2, and M is the data.
Ｃ１＝ｆ（Ｖｉ）、（ｉ＝１．２．・・・、Ｍ） ・・
（６）ルに設けたデータ数である。さらに、ガス６
濃度の定量結果Ｃはこの索引テーブルと（７）式の線形
補間によって算出される。C1=f(Vi), (i=1.2...,M)...
(6) This is the number of data provided in the file. Furthermore, the quantitative result C of the concentration of gas 6 is calculated using this index table and linear interpolation of equation (7).
（タタシ、Ｖｉ” ｌ Ｖ”（ｒＬ）ｌ Ｖｉ”＋＋
）（ｖｉｉｉ） 手順（ｖ）〜（ＶＩＤを実施する間、
すでに素子温ｇ がＴＷに保持されていることを考慮し
て（１）へ戻る。(Tatashi, Vi” l V”(rL)l Vi”++
) (viii) Steps (v) to (while performing VID,
Considering that the element temperature g is already maintained at TW, return to (1).
本実施例に示す装置に５ｎ０２素子以外のたとえば先に
説明したＷＯｓ素子を適用することは容易である。換言
すれば、同一の装置構成において、適用する検出素子と
それに対応する標準スペクトル、ガス濃度テーブル等の
記憶データを交換することにより、極めて広範なガス種
に対応することが可能となる。It is easy to apply, for example, the above-described WOs element other than the 5n02 element to the device shown in this embodiment. In other words, in the same device configuration, by exchanging stored data such as applicable detection elements and corresponding standard spectra, gas concentration tables, etc., it becomes possible to deal with an extremely wide range of gas types.
次に、本出願の第２の発明（複数種類の半導体ガス検出
素子を用いたガス検出装置）について述べる。Next, the second invention of the present application (a gas detection device using multiple types of semiconductor gas detection elements) will be described.
５ｙＬ０２． ＷＯｓの他にも検出素子の母材として使
用できる金属酸化物半導体は多数存在し、さらに、これ
らへの触媒添加条件の適宜な変更、素子構造、製法の変
更、等による特性の異なる検出素子の実現が非常に容易
であることからも、本実施例に示すカス種識別・定量方
式および装置によってガス情報を定めることのできるガ
ス種が、いかに広範に及ぶかということを推察すること
ができる。5yL02. In addition to WOs, there are many metal oxide semiconductors that can be used as base materials for detection elements, and it is possible to create detection elements with different characteristics by appropriately changing the conditions for adding catalyst to them, changing the element structure, and manufacturing method. Since it is very easy to implement, it can be inferred that the range of gas types for which gas information can be determined by the waste type identification/quantification method and device shown in this example is wide.
また特に例を挙げるまでもなく、複数個のカス検出素子
を同時に具備する構成とすれば、ガス情報の検出性能が
飛躍的に向上することは明白である。この場合の回路構
成は複数素子が個別か集積かによって多少異なるが、基
本構成は第８図と同一であり、新らたな技術的問題が発
生する虞はない。Further, without giving any particular example, it is clear that the gas information detection performance will be dramatically improved if a configuration is provided in which a plurality of scum detection elements are provided at the same time. Although the circuit configuration in this case differs somewhat depending on whether the plurality of elements are individual or integrated, the basic configuration is the same as that in FIG. 8, and there is no risk of new technical problems occurring.
上述の原理に基ついて本出願の第２の発明は互いにカス
検出特性を異にする複数個の半導体ガス検出素子と、上
記複数個のガス検出素子の温度を制御する手段と、上記
複数個のカス検出素子の検出出力信号を演算する装置と
を設けて、該複数個のガス検出素子の検出スペクトルな
算出し得るように構成し、かつ、上記演算装置は記憶手
段を備えたものとして複数種類のガスの各種濃度に対応
する標準スペクトルを記憶せしめ、前記の算出したスペ
クトルと記憶１−ているスペクトルとを比較し゛Ｃ検出
ガスの種類及び濃度を算出できるように構成することに
より、前記第１の発明に比して更に多種類のガスの種類
。Based on the above-mentioned principle, a second invention of the present application includes a plurality of semiconductor gas detection elements having mutually different scum detection characteristics, a means for controlling the temperature of the plurality of gas detection elements, and a means for controlling the temperature of the plurality of gas detection elements. A device for calculating detection output signals of the gas detection elements is provided, and the calculation device is configured to be able to calculate the detection spectra of the plurality of gas detection elements, and the calculation device is equipped with a storage means and can be used in a plurality of types. By storing standard spectra corresponding to various concentrations of the first gas, and comparing the calculated spectrum with the stored spectrum, the type and concentration of the detected gas can be calculated. Even more types of gas than the invention of .
濃度を検出することができる。Concentration can be detected.
本発明の装置においては具備するガス検出素子に対して
、たとえばある特定種類のガスにだけ反応するといった
特殊な仕様を要求する必要はなく、素子温度の変動に従
ってガス検出出力が描くスペクトルがガス種に応じて特
異的に異なれば実用に適うため、安価な素子材料の使用
が可能となると同時に、特殊仕様を満足する検出素子の
開発を待つことなく装置の実用化、製品化を可能とする
ことができる。In the device of the present invention, there is no need to require the gas detection element to have special specifications, such as reacting only to a certain type of gas, and the spectrum drawn by the gas detection output varies depending on the gas type according to fluctuations in element temperature. Since it is suitable for practical use if it is specifically different depending on the specifications, it is possible to use inexpensive element materials, and at the same time, it is possible to put the device into practical use and commercialize it without waiting for the development of a detection element that satisfies special specifications. I can do it.
さらに、演算過程で引用する特性テークを外部から変更
することにより、同一仕様の装置でも種々のガス、臭い
、溶剤臭等のガス情報を検出することが可能であるため
、広範な応用分野を有する安価なガス検出装置を実現す
ることができる。Furthermore, by externally changing the characteristics taken in the calculation process, it is possible to detect gas information such as various gases, odors, solvent odors, etc. even with devices with the same specifications, so it has a wide range of applications. An inexpensive gas detection device can be realized.
以上詳述したように、本出願の第１の発明によれば１個
のガス検出素子を用いて多種類の特定ガス、混合ガス、
成分ガスの種類及び濃度を検出し得る小形、低価格のガ
ス検出装置を構成することができる。また、本出願の第
２の発明によれば小数のガス検出素子を用いて多種類の
特定カス、混合ガス、成分ガスの種類及び＃度を検出す
ることができる。As detailed above, according to the first invention of the present application, one gas detection element can be used to detect many kinds of specific gases, mixed gases,
A small, low-cost gas detection device capable of detecting the type and concentration of component gases can be constructed. Further, according to the second invention of the present application, it is possible to detect many kinds of specific scum, mixed gas, and component gas types and degrees using a small number of gas detection elements.
第１図は検出素子の実施例を示す概略構造図であって同
図（ａ）は平面図、同図（ｂ）け裏面図、同図（Ｃ）は
同図（ａ）のＡＡ’断面図、第２図は検出素子のヒータ
電圧−素子温度を示す図婢、第３図は制御済の素子温度
特性図表、第４図はＷＯｓ検出素子の検出特性図表、第
５図は８ｎ０２素子の検出特性図≠、第６図及び第７図
はＳｎ’０２素子の温度０
特性図表、第８図はＳｎＯ２素子を用いた本発明のガス
検出装置の１実施例の概要的な構成図である。
８１・・・ガス検出素子、８２・・・マイクロプロセッ
サ、８３・・・Ｄ／Ａ変換器、８４・・・電圧ンオロワ
、８５・・加熱用ヒータ、ｓｓ Ａ／Ｄ変換器、８９・
・・モニタ。
第１図
（ρ） （ね）
／、ｑ
第 ３２
テ゛）ジ゛フル＠９ｎ （Ｉニー７ｅｌ−Ｖ（−ｎ））
茅 ４ 図
ＷＯ２束子温度（０Ｃ）
第 ５ 図
７７” Ｘｉｍ／θＤＯ、Ｐ、Ｐ、＋７２５η０２素子
温度（０Ｑ）FIG. 1 is a schematic structural diagram showing an embodiment of the detection element, in which (a) is a plan view, (b) is a back view, and (C) is a cross section taken along line AA' in (a). Fig. 2 is a diagram showing the heater voltage vs. element temperature of the detection element, Fig. 3 is a chart of controlled element temperature characteristics, Fig. 4 is a detection characteristic chart of the WOs detection element, and Fig. 5 is a chart of the 8n02 element. Detection characteristic diagram≠, Figures 6 and 7 are temperature 0 characteristic diagrams of the Sn'02 element, and Figure 8 is a schematic configuration diagram of an embodiment of the gas detection device of the present invention using the SnO2 element. . 81... Gas detection element, 82... Microprocessor, 83... D/A converter, 84... Voltage controller, 85... Heating heater, ss A/D converter, 89...
··monitor. Figure 1 (ρ) (Ne) /,q 32nd Tee) Differ @9n (I knee 7el-V(-n))
Kaya 4 Figure WO2 bundler temperature (0C) Figure 5 77'' Xim/θDO, P, P, +725η02 element temperature (0Q)
Claims (2)
出素子の温度を制御する手段と、上記１個のガス検出素
子の検出出力信号を演算する装置とを設けて、前記１個
のガス検出素子の検出スペクトルを算出し得るように構
成し、かつ、上記演算装置は記憶手段を備えたものとし
て複数種類のガスの各種濃度に対応する標準スペクトル
を記憶せしめ、前記の算出したスペクトルと記憶してい
るスペクトルとを比較して検出ガスの種類及び濃度を算
出できるように構成したことを特徴とするガス検出装置
。(1) One semiconductor gas detection element, means for controlling the temperature of the one gas detection element, and a device for calculating a detection output signal of the one gas detection element, The arithmetic unit is configured to be able to calculate the detection spectrum of the gas detection element, and the arithmetic unit is equipped with a storage means to store standard spectra corresponding to various concentrations of a plurality of gases, 1. A gas detection device characterized in that the type and concentration of a detected gas can be calculated by comparing the stored spectrum with a stored spectrum.
ス検出素子と、上記複数個のガス検出素子の温度を制御
する手段と、上記複数個のガス検出素子の検出出力信号
を演算する装置とを設けて、該複数個のガス検出素子の
検出スペクトルを算出し得るように構成し、かつ、上記
演算装置は記憶手段を備えたものとして複数種類のガス
の各種濃度に対応する標準スペクトルを記憶せしめ、前
記の算出したスペクトルと記憶しているスペクトルとを
比較して検出ガスの種類及び濃度を算出できるように構
成したことを特徴とするガス検出装置。(2) A plurality of semiconductor gas detection elements having mutually different gas detection characteristics, means for controlling the temperature of the plurality of gas detection elements, and a device for calculating detection output signals of the plurality of gas detection elements. and is configured to be able to calculate the detection spectra of the plurality of gas detection elements, and the arithmetic unit is equipped with a storage means to store standard spectra corresponding to various concentrations of the plurality of gases. A gas detection device characterized in that it is configured to be able to store the calculated spectrum and calculate the type and concentration of the detected gas by comparing the calculated spectrum with the stored spectrum.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5426684A JPS60198446A (en) | 1984-03-23 | 1984-03-23 | Gas detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5426684A JPS60198446A (en) | 1984-03-23 | 1984-03-23 | Gas detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60198446A true JPS60198446A (en) | 1985-10-07 |
| JPH0532695B2 JPH0532695B2 (en) | 1993-05-17 |
Family
ID=12965763
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5426684A Granted JPS60198446A (en) | 1984-03-23 | 1984-03-23 | Gas detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60198446A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6148756A (en) * | 1984-08-17 | 1986-03-10 | Mitsubishi Electric Corp | Gas detecting device |
| JPH0815201A (en) * | 1994-06-28 | 1996-01-19 | Dkk Corp | Gas sensor for food quality check |
| JP2002031615A (en) * | 2000-07-13 | 2002-01-31 | Fis Kk | Ketone sensitive element |
| EP1416268A1 (en) * | 2002-10-31 | 2004-05-06 | Industrial Technology Research Institute | Intelligent gas identification system and method thereof |
| JP2007024508A (en) * | 2005-07-12 | 2007-02-01 | Fuji Electric Fa Components & Systems Co Ltd | Membrane gas sensor |
| JP2007218704A (en) * | 2006-02-15 | 2007-08-30 | Futaba Electronics:Kk | Smell discrimination method, smell measuring method, smell discrimination program, smell discrimination device and smell measuring instrument |
| JP2011027752A (en) * | 2010-11-08 | 2011-02-10 | Fuji Electric Systems Co Ltd | Thin film gas sensor |
| JP2014533354A (en) * | 2011-10-07 | 2014-12-11 | エイチツースキャン・コーポレーション | Techniques for calculating gas concentrations in a fluid environment. |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57198854A (en) * | 1981-06-02 | 1982-12-06 | Riken Keiki Kk | Identifying and detecting device for gas |
| JPS58189547A (en) * | 1982-04-15 | 1983-11-05 | ツエルベルス・アクチエンゲゼルシヤフト | Gas or vapor alarm device |
-
1984
- 1984-03-23 JP JP5426684A patent/JPS60198446A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57198854A (en) * | 1981-06-02 | 1982-12-06 | Riken Keiki Kk | Identifying and detecting device for gas |
| JPS58189547A (en) * | 1982-04-15 | 1983-11-05 | ツエルベルス・アクチエンゲゼルシヤフト | Gas or vapor alarm device |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6148756A (en) * | 1984-08-17 | 1986-03-10 | Mitsubishi Electric Corp | Gas detecting device |
| JPH0435029B2 (en) * | 1984-08-17 | 1992-06-09 | Mitsubishi Electric Corp | |
| JPH0815201A (en) * | 1994-06-28 | 1996-01-19 | Dkk Corp | Gas sensor for food quality check |
| JP2002031615A (en) * | 2000-07-13 | 2002-01-31 | Fis Kk | Ketone sensitive element |
| EP1416268A1 (en) * | 2002-10-31 | 2004-05-06 | Industrial Technology Research Institute | Intelligent gas identification system and method thereof |
| JP2007024508A (en) * | 2005-07-12 | 2007-02-01 | Fuji Electric Fa Components & Systems Co Ltd | Membrane gas sensor |
| JP2007218704A (en) * | 2006-02-15 | 2007-08-30 | Futaba Electronics:Kk | Smell discrimination method, smell measuring method, smell discrimination program, smell discrimination device and smell measuring instrument |
| JP2011027752A (en) * | 2010-11-08 | 2011-02-10 | Fuji Electric Systems Co Ltd | Thin film gas sensor |
| JP2014533354A (en) * | 2011-10-07 | 2014-12-11 | エイチツースキャン・コーポレーション | Techniques for calculating gas concentrations in a fluid environment. |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0532695B2 (en) | 1993-05-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Yuan et al. | Detection and identification of volatile organic compounds based on temperature-modulated ZnO sensors | |
| Mitzner et al. | Development of a micromachined hazardous gas sensor array | |
| Sears et al. | Algorithms to improve the selectivity of thermally-cycled tin oxide gas sensors | |
| de Lacy Costello et al. | Thick film organic vapour sensors based on binary mixtures of metal oxides | |
| Tomchenko et al. | WO3 thick-film gas sensors | |
| TWI354783B (en) | System and method for sensing and analyzing gases | |
| US4457161A (en) | Gas detection device and method for detecting gas | |
| Yang et al. | A novel electronic nose based on porous In2O3 microtubes sensor array for the discrimination of VOCs | |
| JPH0797097B2 (en) | Chemical sensor for carbon monoxide detection | |
| Ngo et al. | High performance of a gas identification system using sensor array and temperature modulation | |
| Schwebel et al. | A selective, temperature compensated O2 sensor based on Ga2O3 thin films | |
| US5670949A (en) | Carbon monoxide/hydrocarbon thin film sensor | |
| GB2426592A (en) | Measurement of gas concentration by a pellistor having a single pulse applied to it | |
| JPS60198446A (en) | Gas detector | |
| Rettig et al. | Direct thermoelectric gas sensors: Design aspects and first gas sensors | |
| US20240036016A1 (en) | Gas sensor calibration method | |
| US6843900B2 (en) | Potentiometric NOx sensors based on yttria-stabilized zirconia with zeolite modified electrode | |
| Murthy et al. | Application of principal component analysis to gas sensing characteristics of Cr0. 8Fe0. 2NbO4 thick film array | |
| DE102018122860A1 (en) | Method for operating a sensor device | |
| US7900501B2 (en) | Air quality monitor | |
| Zhang et al. | Mixed-potential gas sensor with PtAu-8YSZ sensing electrode: Electric potential difference measurements at isothermal and thermo-cyclic operation | |
| Neri et al. | FeSrTiO3-based resistive oxygen sensors for application in diesel engines | |
| Kohli et al. | Niobium pentoxide as a lean-range oxygen sensor | |
| GB2167192A (en) | Gas sensor | |
| US4332772A (en) | Portable gas detector |