JPH06207903A

JPH06207903A - Measuring apparatus for concentration of gas

Info

Publication number: JPH06207903A
Application number: JP1929293A
Authority: JP
Inventors: Isao Hishikari; 功菱刈; Katsuyuki Miyauchi; 克之宮内; Kosei Aikawa; 孝生相川
Original assignee: Chino Corp
Current assignee: Chino Corp
Priority date: 1993-01-11
Filing date: 1993-01-11
Publication date: 1994-07-26

Abstract

PURPOSE:To provide a gas concentration measuring apparatus which can measure the concentration of a gas stably. CONSTITUTION:A gas is introduced into a container 1, which is heated to a predetermined temperature T1 by a heating body 3. The radiation energy through a window glass 2 is input to a detecting element 6 via a filter 5, whereby a detecting signal V1 is obtained. The detecting element 6 is held by a holding body 7. A measuring means 9 makes corrections based on the detecting signal V1 with using a temperature T2 of the holding body 7 itself which is detected by a temperature sensor 8. Accordingly, an output Eo corresponding to the concentration of the gas is obtained. True temperature of a heater 3 by the heating body 3 is controlled to be constant by a temperature sensor 30 and a controlling means 4. The output T1 is utilized for corrections by the measuring means upon necessities.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】この発明は、光学的に炭酸ガス
（二酸化炭素、ＣＯ２）等のガス濃度を測定するガス
濃度測定装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas concentration measuring device for optically measuring the concentration of carbon dioxide gas (carbon dioxide, CO2) or the like.

【０００２】[0002]

【従来の技術】従来、ＣＯ２等のガス濃度を測定する
場合、光源からの光を測定対象に投光し、その吸収から
ガス濃度を測定していた。また、測定ガスに関する測定
波長と基準波長との２色を利用して測定する方法もあ
る。2. Description of the Related Art Conventionally, when measuring the gas concentration of CO2 or the like, light from a light source is projected onto a measurement object and the gas concentration is measured from its absorption. There is also a method of measuring using two colors of a measurement wavelength related to the measurement gas and a reference wavelength.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、前者で
は、光源を使用するため、その電源変動、光路の汚れ等
による影響を受けやすく誤差を発生する問題点があっ
た。また、後者では、２色のためフィルタ、素子等を多
く必要となり、構造が複雑となる問題点があった。However, in the former case, since the light source is used, there is a problem that it is easily affected by fluctuations in the power source, dirt on the optical path, etc., and an error occurs. In the latter case, since there are two colors, a large number of filters, elements, etc. are required, and the structure becomes complicated.

【０００４】この発明の目的は、以上の点に鑑み、安定
的にガス濃度を測定することができるガス濃度測定装置
を提供することである。In view of the above points, an object of the present invention is to provide a gas concentration measuring device capable of stably measuring the gas concentration.

【０００５】[0005]

【課題を解決するための手段】この発明は、測定ガスが
供給され加熱体で所定温度に加熱される容器と、この容
器内からの放射エネルギーを検出する検出手段と、この
検出手段の温度を検出する温度センサと、前記検出手段
の出力を温度センサの出力で補正してガス濃度を測定す
る測定手段とを備えるようにしたガス濃度測定装置であ
り、また、前記容器は、上方に行くに従って狭くなる傾
斜状とされたことを特徴とするようにしたものである。SUMMARY OF THE INVENTION According to the present invention, a container to which a measurement gas is supplied and heated to a predetermined temperature by a heating body, a detecting unit for detecting radiant energy from the container, and a temperature of the detecting unit are provided. A gas concentration measuring device equipped with a temperature sensor for detecting, and a measuring means for measuring the gas concentration by correcting the output of the detecting means with the output of the temperature sensor, and the container becomes higher as it goes upward. It is characterized by having a narrowed slope.

【０００６】[0006]

【実施例】図１は、この発明の一実施例を示す構成説明
図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

【０００７】図において、１は、測定ガスＡが導入口１
１から導入、供給され、排出口１２から排出される容器
（測定セル）で、下部に窓２を有している。容器１は、
アルミニウムＡｌ等で内面の反射率を高めてあり、その
外周には、加熱体（ヒータ）３が設けられ、温度センサ
３０でその温度Ｔ１が測定され、制御手段４で図示しな
い電源から電力を供給し、所定温度となるよう制御され
る。そして、容器１は、外側が断熱材１０で断熱されて
いる。In the figure, reference numeral 1 indicates an inlet 1 for the measuring gas A.
A container (measurement cell) that is introduced and supplied from 1 and discharged from the discharge port 12, and has a window 2 at the bottom. Container 1
The reflectance of the inner surface is increased with aluminum Al or the like, and a heater (heater) 3 is provided on the outer periphery thereof, the temperature T1 is measured by a temperature sensor 30, and power is supplied from a power source (not shown) by the control means 4. Then, the temperature is controlled to reach a predetermined temperature. The outside of the container 1 is insulated by the heat insulating material 10.

【０００８】窓ガラス２の近くには、前面に測定ガス
（たとえばＣＯ２）に相当する透過波長をもつフィル
タ５を有し検出素子７を保持する熱伝導が良好な金属ブ
ロック等よりなる保持体７が設けられこれら検出素子６
等で検出手段を構成し、容器１の内部からの放射エネル
ギーがフィルタ５を介し検出素子６に入射する。この検
出素子６または保持体７の温度Ｔ２は温度センサ８で検
出され検出素子６の出力Ｖ１とともに測定手段９に供給
され補正演算がなされガス濃度の測定が行われる。な
お、検出素子６が焦電素子等の場合は、フィルタ５と窓
２との間に光を断続するためのモータＭで回転するチョ
ッパ１３を設けるようにすればよい。Near the window glass 2, there is provided on the front surface a filter 5 having a transmission wavelength corresponding to the measurement gas (for example, CO 2), and a holder 7 made of a metal block or the like having a good heat conduction for holding the detection element 7. Is provided with these detection elements 6
The radiant energy from the inside of the container 1 is incident on the detection element 6 through the filter 5 and the like. The temperature T2 of the detecting element 6 or the holder 7 is detected by the temperature sensor 8 and is supplied to the measuring means 9 together with the output V1 of the detecting element 6, and the correction calculation is performed to measure the gas concentration. When the detection element 6 is a pyroelectric element or the like, a chopper 13 rotated by the motor M for interrupting light may be provided between the filter 5 and the window 2.

【０００９】また、必要に応じ、温度センサ３の出力Ｔ
１を直接または制御手段４を介し測定手段９に供給し、
用いるようにしてもよい。If necessary, the output T of the temperature sensor 3
1 to the measuring means 9 directly or via the control means 4,
You may use it.

【００１０】つまり、容器１からの放射エネルギーを受
光する検出素子６の出力Ｖ１は、容器１の内部からの放
射エネルギーＬｏと、検出素子６等の温度Ｔ２に関連す
る検出素子６等を含んで保持する保持体７から輻射され
る放射エネルギーＬ２との差に対応し、概略下式とな
る。That is, the output V1 of the detection element 6 which receives the radiant energy from the container 1 includes the radiant energy Lo from the inside of the container 1 and the detection element 6 related to the temperature T2 of the detection element 6 and the like. Corresponding to the difference with the radiant energy L2 radiated from the holding body 7 to be held, the following formula is approximately obtained.

【００１１】Ｖ１＝ｋ・（Ｌｏ−Ｌ２）（１）ここでｋは定数で、検出素子６の温度Ｔ２が変動すれ
ば、Ｌ２も変動するので補償する必要がある。V1 = k · (Lo−L2) (1) Here, k is a constant, and if the temperature T2 of the detection element 6 changes, L2 also changes, and therefore it is necessary to compensate.

【００１２】次に容器１の内部からの放射エネルギーＬ
ｏは測定ガスの濃度Ｃの関数である放射率を含む放射エ
ネルギーＬｇ（ｃ）と容器１内の壁からの温度Ｔ１に相
当する放射エネルギーＬ１との和に相当し、温度Ｔ１が
一定であればＬ１は一定で既知となり、次式が成り立
つ。Next, the radiant energy L from the inside of the container 1
o corresponds to the sum of the radiant energy Lg (c) including the emissivity that is a function of the concentration C of the measurement gas and the radiant energy L1 corresponding to the temperature T1 from the wall inside the container 1, and the temperature T1 may be constant. For example, L1 is constant and known, and the following equation holds.

【００１３】Ｌｏ＝Ｌｇ（ｃ）＋Ｌ１（２）（２）式を（１）式へ代入すると次式が得られる。Lo = Lg (c) + L1 (2) Substituting the expression (2) into the expression (1), the following expression is obtained.

【００１４】Ｖ１＝ｋ・（Ｌｇ（ｃ）＋Ｌ１−Ｌ２）（３）ここで検出素子６等の温度Ｔ２を温度センサ８で測定し
て測定手段９で放射エネルギーＬ２に相当する信号Ｖ２
（ｋ・Ｌ２に相当）に換算して加算することにより検出
素子６を保持する保持体７等の温度変動を除去した出力
Ｅｏが次式より得られる。V1 = k · (Lg (c) + L1-L2) (3) Here, the temperature T2 of the detection element 6 or the like is measured by the temperature sensor 8, and the signal V2 corresponding to the radiant energy L2 is measured by the measuring means 9.
(Equivalent to k · L2) is converted and added to obtain the output Eo from which the temperature fluctuation of the holding body 7 or the like holding the detection element 6 is removed.

【００１５】Ｅｏ＝Ｖ１＋Ｖ２＝ｋ・（Ｌｇ（ｃ）＋Ｌ１−Ｌ２）＋ｋＬ２＝ｋ・（Ｌｇ（ｃ）＋Ｌ１）（４）この（４）式でＬ１は、温度Ｔ１が一定であれば所定値
であり、また、測定で求まるので、この出力Ｅｏからガ
ス濃度Ｃが求まる。このようにして、検出素子６の出力
Ｖ１に対し、その温度Ｔ２で補正することにより、容器
１内のガス濃度が求まる。Eo = V1 + V2 = k. (Lg (c) + L1-L2) + kL2 = k. (Lg (c) + L1) (4) In this equation (4), L1 is a predetermined value if the temperature T1 is constant. Further, since it can be obtained by measurement, the gas concentration C can be obtained from this output Eo. In this way, the gas concentration in the container 1 can be obtained by correcting the output V1 of the detection element 6 with the temperature T2 thereof.

【００１６】また、容器１の上部または容器１全体は、
上方に行くに従って狭くなる傾斜状の構造とされている
ので、ガスが円滑に上方に抜けることができガス置換性
がよく、応答性が高まり、また、図において点線で光路
例を示すように、容器１内で十分な多重反射がくり返さ
れるので光路長が長くなり、小型であっても十分な感度
が得られる。The upper part of the container 1 or the entire container 1 is
Since it has an inclined structure that narrows as it goes upward, the gas can smoothly escape upward, the gas replacement property is good, the response is enhanced, and as shown in the figure by the dotted line optical path, Since sufficient multiple reflection is repeated in the container 1, the optical path length becomes long, and sufficient sensitivity can be obtained even with a small size.

【００１７】この（４）式の示すように、測定手段９で
検出素子６の容器１内からの放射エネルギーの検出出力
Ｖ１に対し、温度センサ３０、８の出力Ｔ１、Ｔ２で補
正するようにすることで高精度にガス濃度を測定するこ
とができる。As shown in the equation (4), the detection output V1 of the radiant energy from the inside of the container 1 of the detection element 6 by the measuring means 9 is corrected by the outputs T1 and T2 of the temperature sensors 30 and 8. By doing so, the gas concentration can be measured with high accuracy.

【００１８】また、測定ガスがない状態での検出素子６
の出力は次式となり、Ｖ１＝ｋ・Ｌ１（５）この出力Ｖ１に対し温度センサ３０の温度Ｔ１に対応す
る出力Ｌ１を減算すればＶ１＝０となり、校正もでき
る。次いで測定ガスを導入して測定すればよい。なお、
検出素子６を保持する保持体７の部分の温度Ｔ２を一定
となるように制御する等して一定温度としておいても同
等の効果が得られる。Further, the detection element 6 in the absence of measuring gas
V1 = k · L1 (5) If the output L1 corresponding to the temperature T1 of the temperature sensor 30 is subtracted from this output V1, then V1 = 0 and calibration is possible. Then, a measurement gas may be introduced and measurement may be performed. In addition,
Even if the temperature T2 of the portion of the holder 7 holding the detection element 6 is controlled to be constant and the temperature is kept constant, the same effect can be obtained.

【００１９】[0019]

【発明の効果】以上述べたように、この発明は、検出素
子を保持する保持体自体の温度を温度センサで検出して
補正するようにしているので、周囲の温度が変動しても
安定的に測定することができる。また、容器の温度を測
定して補正演算をすることにより、加熱体の温度変動に
対応できる。また、容器の形状を上方で狭くすることに
より、ガス置換性が良好で、応答が速く、また、容器内
で十分な多重反射がくり返されるので光路長が長くな
り、小型で十分な性能が得られる。As described above, according to the present invention, the temperature of the holder itself that holds the detecting element is detected and corrected by the temperature sensor, so that it is stable even if the ambient temperature changes. Can be measured. Further, by measuring the temperature of the container and performing the correction calculation, it is possible to cope with the temperature fluctuation of the heating element. Further, by narrowing the shape of the container upward, the gas replacement property is good, the response is fast, and the sufficient multiple reflection is repeated in the container, so that the optical path length is long, and the small size provides sufficient performance. can get.

【図面の簡単な説明】[Brief description of drawings]

【図１】この発明の一実施例を示す構成説明図である。FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

【符号の説明】[Explanation of symbols]

１容器２窓３加熱体３０、８加熱体４制御装置５フィルタ６検出素子７保持体９測定手段１０断熱材１１導入口１２排出口１３チョッパ DESCRIPTION OF SYMBOLS 1 Container 2 Window 3 Heating body 30, 8 Heating body 4 Control device 5 Filter 6 Detecting element 7 Holding body 9 Measuring means 10 Insulating material 11 Inlet port 12 Discharge port 13 Chopper

Claims

【特許請求の範囲】[Claims]

【請求項１】測定ガスが供給され加熱体で所定温度に加
熱される容器と、この容器内からの放射エネルギーを検
出する検出手段と、この検出手段の温度を検出する温度
センサと、前記検出手段の出力を温度センサの出力で補
正してガス濃度を測定する測定手段とを備えたことを特
徴とするガス濃度測定装置。1. A container to which a measuring gas is supplied and which is heated to a predetermined temperature by a heating body, a detecting means for detecting radiant energy from the inside of the container, a temperature sensor for detecting the temperature of the detecting means, and the detecting means. A gas concentration measuring device, comprising: a measuring unit that corrects an output of the unit with an output of a temperature sensor to measure a gas concentration.

【請求項２】測定ガスが供給され加熱体で所定温度に加
熱される容器と、この容器内からの放射エネルギーを検
出する検出手段と、この検出手段の出力からガス濃度を
測定する測定手段とを備え、前記容器は、容器全体また
は容器の上部が上方に行くに従って狭くなる傾斜状とさ
れたことを特徴とするガス濃度測定装置。2. A container to which a measuring gas is supplied and heated to a predetermined temperature by a heating body, a detecting means for detecting radiant energy from the inside of the container, and a measuring means for measuring a gas concentration from an output of the detecting means. The gas concentration measuring device according to claim 1, wherein the container has an inclined shape in which an entire container or an upper portion of the container becomes narrower as it goes upward.