JP2600198B2 - Nitrogen oxide measuring device - Google Patents
Nitrogen oxide measuring deviceInfo
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- JP2600198B2 JP2600198B2 JP24858987A JP24858987A JP2600198B2 JP 2600198 B2 JP2600198 B2 JP 2600198B2 JP 24858987 A JP24858987 A JP 24858987A JP 24858987 A JP24858987 A JP 24858987A JP 2600198 B2 JP2600198 B2 JP 2600198B2
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Description
【発明の詳細な説明】 （イ）産業上の利用分野 この発明は、窒素酸化物測定装置に関する。さらに詳
しくは、ガス中のNO2量、NO量やこれらの合計量であるN
Ox量の測定に用いられる窒素酸化物測定装置に関する。The present invention relates to an apparatus for measuring nitrogen oxides. More specifically, the amount of NO 2 in the gas, the amount of NO
The present invention relates to a nitrogen oxide measuring device used for measuring the amount of Ox.
（ロ）従来の技術 窒素酸化物を測定する装置として従来からNO2−NO変
換器とオゾンによるNOの化学発光検出系とを組合せた装
置が知られており、ことにNO、NO2及びNOxを測定できる
装置として、第３図に示すごとき、分岐流路８を用いた
フロー式の測定装置が知られている。図において、NOx
測定時には、二方切換弁９が実線側に切換えられ、試料
ガス供給部２からの試料ガスは一定圧力下ガス流路５を
通じてNO2−NO変換器３に導入される。ここでNO2はNOに
変換され、試料自体に含まれていたNOと共にオゾンによ
る化学発光検出器４に供給され、NO2とNOの合計量に対
応する化学発光量が検出されてNOx量が換算算出される
（NOx測定モード）。一方、NO側定時には切換弁７が破
線側に切換えられ、その結果、試料中のNOのみが検出器
４で検出されてNO量が換算算出される（NO測定モー
ド）。一方、NO2量は上記NOx量からNO量を減算すること
により算出される。(B) Conventional technology As a device for measuring nitrogen oxides, a device combining a NO 2 -NO converter and a chemiluminescence detection system of NO with ozone has been known, and in particular, NO, NO 2 and NOx. As shown in FIG. 3, a flow-type measuring device using a branch flow path 8 is known as a device capable of measuring the flow rate. In the figure, NOx
At the time of measurement, the two-way switching valve 9 is switched to the solid line side, and the sample gas from the sample gas supply unit 2 is introduced into the NO 2 -NO converter 3 through the gas flow path 5 under a constant pressure. Here, NO 2 is converted to NO, and supplied to the chemiluminescence detector 4 using ozone together with NO contained in the sample itself, and the chemiluminescence amount corresponding to the total amount of NO 2 and NO is detected, and the NOx amount is reduced. Conversion is calculated (NOx measurement mode). On the other hand, when the NO side is fixed, the switching valve 7 is switched to the broken line side. As a result, only the NO in the sample is detected by the detector 4 and the NO amount is calculated and calculated (NO measurement mode). On the other hand, the NO 2 amount is calculated by subtracting the NO amount from the NOx amount.
（ハ）発明が解決しようとする問題点 しかしながら、上記従来の装置においては、試料ガス
として、NOのみを含む窒素ガスを導入した場合には本来
NOx測定モードとNO測定モードとの値が一致すべきであ
るが、実際には異なる場合が多く、このような流路の特
性の差に起因して、ことにNO2を換算算出する際に誤差
を生じる問題があった。そしてこの傾向は高感度測定
（NOxとして1ppm以下）の場合にとくに問題であった。(C) Problems to be solved by the invention However, in the above-mentioned conventional apparatus, when a nitrogen gas containing only NO is introduced as a sample gas,
When the value of the NOx measurement mode and the NO measurement mode should match actually often different, which due to the difference in characteristics of the flow path, in particular in terms of calculating the NO 2 There was a problem that caused an error. This tendency was particularly problematic in the case of high-sensitivity measurement (1 ppm or less as NOx).
さらに、切換弁７を切換えた場合に、NO2−NO変換器
３内でのガス成分の吸脱着の影響により、検出器の出力
値が安定するのに時間を要し、そのため濃度変動の激し
い試料ガスを対象とする測定においては、正しい窒素酸
化物の定量が行な得ない問題もあった。Further, when the switching valve 7 is switched, it takes time for the output value of the detector to stabilize due to the effect of adsorption and desorption of gas components in the NO 2 -NO converter 3, and therefore, the concentration fluctuation is severe. In the measurement for the sample gas, there was also a problem that accurate determination of nitrogen oxides could not be performed.
この発明は、かかる問題点を解消すべくなされたもの
であり、ことにNO2−NO変換器への試料ガスの供給を維
持した状態でしかもより正確に試料ガス中のNO、NO2及
びNOxを定量できる測定装置を提供しようとするもので
ある。The present invention has been made to solve such a problem, and in particular, while maintaining the supply of the sample gas to the NO 2 -NO converter, and more accurately, NO, NO 2 and NOx in the sample gas. It is an object of the present invention to provide a measuring device capable of quantifying the amount of sucrose.
（ニ）問題点を解決するための手段 かくしてこの発明によれば、試料ガス供給部からNO2
−NO変換器を経て化学発光式NO検出部へ延設されるガス
流路と、このガス流路のNO2−NO変換器の前段から分岐
し後段へ接続されるガスバイパス流路とを備え、このバ
イパス流路途中に該流路の流量抵抗の変動手段を設けて
なる窒素酸化物測定装置が提供される。(D) Means for solving the problems Thus, according to the present invention, the NO 2 gas is supplied from the sample gas supply unit.
A gas flow path extending to the chemiluminescence NO detection unit via the -NO converter, and a gas bypass flow path branched from a previous stage of the NO 2 -NO converter of the gas flow path and connected to a subsequent stage. Further, there is provided a nitrogen oxide measuring apparatus provided with a means for varying the flow resistance of the flow path in the middle of the bypass flow path.
この発明は、NO2−NO変換器への試料ガス供給を一定
に継続した状態で、バイパス流路を通じて化学発光式NO
検出部へ無変換の試料ガスを並行して供給できるよう構
成した点を１つの大きな特徴とし、さらにバイパス流路
の開閉あるいはその流量抵抗の変動による検出部での出
力値及びその変化に基づいて、NO、NO2及びNOxを換算定
量しうるよう構成した点を他の大きな特徴とするもので
ある。The present invention, a sample gas supply to the NO 2 -NO converter while continuing constant chemiluminescence through the bypass passage NO
One of the major features is that the sample gas without conversion can be supplied to the detection unit in parallel, and based on the output value at the detection unit and its change due to the opening and closing of the bypass flow path or the fluctuation of its flow resistance. , NO, NO 2 and NOx are another major feature.
この発明のバイパス流路における流量抵抗の変動手段
は、例えば流量抵抗を無限大にできる流路開閉弁で構成
されていてもよく、流量抵抗の異なる複数のバイパス管
とこれらのいずれかを選択する流路選択手段（切換弁
等）で構成されていてもよい。The flow resistance changing means in the bypass flow passage according to the present invention may be constituted by, for example, a flow passage opening / closing valve which can make the flow resistance infinite, and selects a plurality of bypass pipes having different flow resistances and any one of them. It may be constituted by a flow path selecting means (a switching valve or the like).
なお、この発明における試料ガス供給部としては、定
圧ポンプ等により一定の圧力で試料ガスを供給しうる供
給装置を用いるのが適している。Note that, as the sample gas supply unit in the present invention, it is suitable to use a supply device that can supply the sample gas at a constant pressure by a constant pressure pump or the like.
（ホ）作用 一定圧力で試料ガスが供給されている状態で、バイパ
ス流路の流量抵抗を変動させることにより、NO検出部へ
の未変換の試料ガスの導入や導入量の変化が生じるが、
NO2−NO変換器を通じてのガス導入量は一定に維持され
る。そして、検出はガス流路からの変換ガスにバイパス
流路からの未変換ガスが加わった状態で行なわれるが、
ガス流路側の流量が一定に維持されているので、流量抵
抗の変動前後による検出値の大きさは試料中のNO量とNO
2量の簡単な関数となり、これに基づいてNO、NO2及びNO
xが換算定量されることとなる。(E) Function In the state where the sample gas is supplied at a constant pressure, by changing the flow resistance of the bypass flow path, the introduction of the unconverted sample gas to the NO detection unit and a change in the amount of introduction occur.
Amount of gas introduced through the NO 2 -NO converter is kept constant. The detection is performed in a state where the unconverted gas from the bypass channel is added to the converted gas from the gas channel,
Since the flow rate on the gas flow path side is kept constant, the magnitude of the detected value before and after the fluctuation of the flow resistance depends on the NO amount in the sample and the NO
Two simple functions, based on which NO, NO 2 and NO
x is converted and quantified.
（ヘ）実施例 第１図に示す１は、この発明の窒素酸化物測定装置の
一実施例を示すものである。図において、窒素酸化物測
定装置１は、略一定の圧力でガスを吸引供給しうる圧力
ポンプを備えた試料ガス供給部２から、NO2−NO変換器
３を経て化学発光NO検出部４へ延設されるガス流路５
と、このガス流路５の変換器３の前段（ａ）から直接分
岐した後段（ｂ）へ接続されるガスバイパス流路６とを
備えてなる。(F) Embodiment 1 shown in FIG. 1 shows an embodiment of the nitrogen oxide measuring apparatus of the present invention. In the figure, a nitrogen oxide measuring device 1 is connected to a chemiluminescence NO detection unit 4 via a NO 2 -NO converter 3 from a sample gas supply unit 2 equipped with a pressure pump capable of sucking and supplying gas at a substantially constant pressure. Extended gas flow path 5
And a gas bypass channel 6 that is connected directly to the latter stage (b) of the gas channel 5 from the former stage (a) of the converter 3.
そして、ガスバイパス流路６には、流路開閉弁７が設
けられており、この開閉により、バイパス流路７の開閉
がなされる。The gas bypass passage 6 is provided with a passage opening / closing valve 7, which opens and closes the bypass passage 7.
図中、41はNO−O3化学発光反応用のオゾン供給部、42
は化学発光強度を測定する光電子増倍管、43は演算表示
部を各々示すものである。また、図中、R1はａ−ｂ間の
流路５の総流量抵抗を、R2は開閉弁７開放時の流路６の
総流量抵抗を各々模式的に示すものである。In the figure, 41 is an ozone supply portion for NO-O 3 chemiluminescent reaction, 42
Denotes a photomultiplier tube for measuring the chemiluminescence intensity, and 43 denotes a calculation display unit. In the figure, R 1 is a total flow resistance of the flow path 5 between a-b, R 2 is indicative respectively schematically the total flow resistance of the flow path 6 of the opening and closing valve 7 open.
なお、上記各流路5,6の流量抵抗は、内径0.3〜0.5mm
のステンレス管で構成し、かつ上記R1とR2は各々供給ガ
スを300ml/分通過しうるように設定されている。この流
量は100〜1000ml/分の間で選定するのが適している。ま
た、NO2−NO変換器３としては触媒処理したステンレス
管と加熱器とからなる還元管を用いたが、例えばカーボ
ンなどの触媒又は反応剤を内蔵した還元管を用いても差
しつかえない。The flow resistance of each of the flow paths 5 and 6 is 0.3 to 0.5 mm in inner diameter.
Of it constituted by stainless steel, and the R 1 and R 2 are set respectively feed gas as can 300 ml / min through. This flow rate is suitably chosen between 100 and 1000 ml / min. Further, as the NO 2 -NO converter 3, a reduction tube including a stainless steel tube subjected to a catalyst treatment and a heater was used. However, a reduction tube containing a catalyst or a reactant such as carbon may be used.
かかる測定装置による分析操作及び機能については以
下説明する。The analysis operation and function of the measuring device will be described below.
まず、測定は開閉弁７の閉鎖時と開放時について行な
われる。まず、閉鎖時においてNOをxppm（ml/m3）、NO2
をyppm含む試料ガスを供給すると、この試料ガスはNO2
−NO変換器３へ300ml/分の流量で導入され、そこでNO2
がNOに変換され、この変換ガス中のNO濃度が検出器４で
検出される。この際の検出信号値は、上記NOとNO2の合
計値、即ちNOx濃度（ｘ＋ｙ）ppmに対応する値Ａとな
る。First, the measurement is performed when the on-off valve 7 is closed and when it is opened. First, when closed, NO was xppm (ml / m 3 ), NO 2
When supplying a sample gas containing yppm a sample gas is NO 2
-Is introduced into the NO converter 3 at a flow rate of 300 ml / min, where the NO 2
Is converted to NO, and the NO concentration in the converted gas is detected by the detector 4. The detection signal value at this time is a value A corresponding to the total value of NO and NO 2 , that is, the NOx concentration (x + y) ppm.
次いで開閉弁７を開放した状態で同様に試料ガスを供
給すると、供給ガス圧が一定であるため前記と同様にNO
2−NO含有試料ガスは300ml/分の流量で変換器３へ導入
された検出器４へ供給されるが、さらに試料ガスはバイ
パス流路６を介して上記ガス流路５内のガスに加わって
検出器４へ供給（300ml/分）される。従って、検出器４
に供給されるガス中には、前記した（ｘ＋ｙ）ppmのNO
成分と、試料中に存在するxppmのNO成分及びyppmのNO2
成分が存在し、この結果検出信号値は、これらNO濃度の
合計に対応する（2x＋ｙ）ppmに相当する値Ｂとなる。Next, when the sample gas is supplied in a state where the on-off valve 7 is opened, NO gas is supplied in the same manner as described above because the supply gas pressure is constant.
The 2- NO-containing sample gas is supplied at a flow rate of 300 ml / min to the detector 4 introduced into the converter 3, and the sample gas is further added to the gas in the gas channel 5 via the bypass channel 6. And supplied to the detector 4 (300 ml / min). Therefore, detector 4
In the gas supplied to the above (x + y) ppm of NO
Component and, NO components xppm present in the sample and yppm of NO 2
As a result, the detection signal value becomes a value B corresponding to (2x + y) ppm corresponding to the sum of these NO concentrations.
従って、下記の連立方程式： （式注、ｋは信号値−濃度換算係数）に基づいてNO濃度
ｘ及びNO2濃度ｙが各々下式： で求められることとなる。Therefore, the following simultaneous equations: (Shikichu, k is the signal value - concentration conversion coefficient) NO concentration x and NO 2 concentration y based on the respective following formula: Will be required.
なお、上記換算係数ｋはNO含有標準ガスに基づいて簡
便に決定できる。例えば、zppmのNOを含む窒素ガスにつ
いて前記と同様に、開閉弁７の閉鎖時及び開放時につい
て測定を行なう。閉鎖時の検出信号値をαとすると開放
時においては検出器への総流量が倍増し検出信号値は２
αに相当する値βとなる。The conversion coefficient k can be easily determined based on the NO-containing standard gas. For example, measurement is performed on the nitrogen gas containing zppm of NO at the time of closing and opening the on-off valve 7 in the same manner as described above. When the detection signal value at the time of closing is α, the total flow rate to the detector doubles at the time of opening and the detection signal value becomes 2
The value β corresponds to α.
ここで（β−α）は値は試料中のNO濃度ｚに対応する
ものである。Here, the value of (β-α) corresponds to the NO concentration z in the sample.
従って、換算係数ｋは下式： に基づいて算出することができる。なお、NOとNO2を共
存する標準ガスを用いても同様にしてｋを簡便に算出す
ることができる。Therefore, the conversion factor k is given by the following equation: Can be calculated based on Note that k can be easily calculated in the same manner even when a standard gas in which NO and NO 2 coexist is used.
なお、例えば100ppmのNO含有窒素ガスを標準ガスとし
て用いた場合、α＝1V,β＝2Vの信号値が得られる条件
で、未知試料の測定値Ａ＝0.4V,B＝0.7Vであると、上記
各式に基づいて、NO濃度30ppm、NO2濃度10ppm、NOx濃度
40ppmが各々算出されることとなる。For example, when 100 ppm of NO-containing nitrogen gas is used as a standard gas, under the condition that a signal value of α = 1 V and β = 2 V is obtained, it is assumed that the measured value A of the unknown sample is 0.4 V and B = 0.7 V. , Based on the above equations, NO concentration 30 ppm, NO 2 concentration 10 ppm, NOx concentration
40 ppm will be calculated for each.
第２図は、流量抵抗の変動手段を、流動抵抗の異なる
二つのバイパス管61,62と、これらのいずれかを選択す
る二方向切換弁63とで構成した以外、第１図と同様に構
成された他の実施例を示すものである。図において流量
抵抗R2は第１図と同一に設定されており、R3は1/2・R2
に設定されている。即ち、流路61選択時には試料ガスは
300ml/分の流量で、流路62選択時には600ml/分の流量で
検出器４方向へ供給される。FIG. 2 is the same as FIG. 1 except that the flow resistance changing means is constituted by two bypass pipes 61 and 62 having different flow resistances and a two-way switching valve 63 for selecting one of them. 13 shows another embodiment that has been performed. In the figure, the flow resistance R 2 is set the same as in FIG. 1, and R 3 is 1/2 · R 2
Is set to That is, when the flow path 61 is selected, the sample gas is
It is supplied to the detector 4 at a flow rate of 300 ml / min and at a flow rate of 600 ml / min when the flow path 62 is selected.
かかる装置においてxppmのNOとyppmのNO2を含む未知
試料を供給した際の検出信号値は、流路61の選択時には
（2x＋ｙ）ppmに対応する値となり、流路62の選択時に
は、（3x＋ｙ）ppmの値を示す。従って、前記実施例と
同様に、これらの連立方程式及び信号値−濃度換算係数
に基づいて、NO濃度、NO2濃度、NOx濃度を算出すること
ができる。なお、流量抵抗は他の組合せであっても同様
である。Detection signal value at the time of supplying the unknown sample containing NO 2 of NO and yppm of xppm in such devices, during the selection of the flow path 61 becomes a value corresponding to (2x + y) ppm, when selecting the flow path 62, (3x + y ) Shows the value of ppm. Therefore, as in the embodiment, these simultaneous equations and signal value - based on the concentration conversion factor, NO concentration, NO 2 concentration, it is possible to calculate the NOx concentration. The same applies to other combinations of flow resistances.
（ヘ）発明の効果 この発明の装置によれば、試料ガスのNO2−NO変換器
への供給を停止することなく継続した状態でNO,NO2及び
NOxを定量することができる。従って、変換器へのガス
の吸脱着に伴なう過渡的な誤差を解消することができ、
窒素酸化物の測定を迅速に行なうことが可能となる。そ
して、さらに従来の測定装置で生じていたNOx測定モー
ドとNO測定モードの切換自体による信号値の変動に基づ
くNO2の誤差を解消することができる。(F) the apparatus according to the effect the invention of the present invention, NO in continuous state without stopping the supply to the NO 2 -NO converter of the sample gas, NO 2 and
NOx can be quantified. Therefore, it is possible to eliminate a transient error caused by adsorption and desorption of gas to and from the converter,
Measurement of nitrogen oxides can be performed quickly. Then, it is possible to eliminate the further error of NO 2 based on the variation of the conventional signal value by switching換自of the measurement had occurred in the apparatus NOx measurement mode and the NO measurement mode.
第１図及び第２図は、各々この発明の窒素酸化物測定装
置の実施例を示す構成説明図、第３図は従来の窒素酸化
物測定装置を例示する構成説明図である。 １……窒素酸化物測定装置、 ２……試料ガス供給部、 ３……NO2−NO変換器、 ４……化学発光NO検出部、５……ガス流路、 ６……ガスバイパス流路、７……流路開閉弁、 41……オゾン供給部、 42……光電子増倍管、43……演算表示部、 61,62……バイパス管、 63……二方切換弁。1 and 2 are explanatory diagrams each showing an embodiment of a nitrogen oxide measuring device according to the present invention, and FIG. 3 is a structural explanatory diagram illustrating a conventional nitrogen oxide measuring device. 1 ...... nitrogen oxide measuring device, 2 ...... sample gas supply unit, 3 ...... NO 2 -NO converter, 4 ...... chemiluminescent NO detector, 5 ...... gas channel 6 ...... gas bypass passage , 7 ... Flow path on-off valve, 41 ... Ozone supply unit, 42 ... Photomultiplier tube, 43 ... Calculation display unit, 61, 62 ... Bypass tube, 63 ... Two-way switching valve.
Claims (3)
化学発光式NO検出部へ延設されるガス流路と、このガス
流路のNO2−NO変換器の前段から分岐し後段へ接続され
るガスバイパス流路とを備え、このバイパス流路途中に
該流路の流量抵抗の変動手段を設けてなる窒素酸化物測
定装置。1. A gas flow path extending from a sample gas supply section to a chemiluminescence NO detection section via a NO 2 -NO converter, and a gas flow path branched from a stage preceding the NO 2 -NO converter. A nitrogen oxide measuring apparatus comprising: a gas bypass flow path connected to a subsequent stage; and a means for varying the flow resistance of the flow path in the middle of the bypass flow path.
る特許請求の範囲第１項記載の測定装置。2. The measuring device according to claim 1, wherein said flow resistance changing means comprises a flow passage opening / closing valve.
複数のバイパス管と、これらのいずれかを選択してバイ
パス流路を構成する流路切換手段とからなる特許請求の
範囲第１項に記載の測定装置。3. The flow rate changing means according to claim 1, wherein said flow rate changing means comprises a plurality of bypass pipes having different flow rate resistances, and a flow path switching means for selecting one of them to form a bypass flow path. The measuring device according to item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24858987A JP2600198B2 (en) | 1987-09-30 | 1987-09-30 | Nitrogen oxide measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24858987A JP2600198B2 (en) | 1987-09-30 | 1987-09-30 | Nitrogen oxide measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6488344A JPS6488344A (en) | 1989-04-03 |
| JP2600198B2 true JP2600198B2 (en) | 1997-04-16 |
Family
ID=17180369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24858987A Expired - Lifetime JP2600198B2 (en) | 1987-09-30 | 1987-09-30 | Nitrogen oxide measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2600198B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6451158B1 (en) * | 1999-12-21 | 2002-09-17 | Lam Research Corporation | Apparatus for detecting the endpoint of a photoresist stripping process |
| CN113552200A (en) * | 2020-04-24 | 2021-10-26 | 广东铭沁环保科技有限公司 | NO in air2Monitoring system and method |
| CN114018848B (en) * | 2021-11-16 | 2022-11-11 | 无锡时和安全设备有限公司 | Visual nitrogen oxide conversion system |
-
1987
- 1987-09-30 JP JP24858987A patent/JP2600198B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6488344A (en) | 1989-04-03 |
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