JPS62291557A - Gas detector - Google Patents
Gas detectorInfo
- Publication number
- JPS62291557A JPS62291557A JP13361786A JP13361786A JPS62291557A JP S62291557 A JPS62291557 A JP S62291557A JP 13361786 A JP13361786 A JP 13361786A JP 13361786 A JP13361786 A JP 13361786A JP S62291557 A JPS62291557 A JP S62291557A
- Authority
- JP
- Japan
- Prior art keywords
- operating temperature
- detection
- gas
- gas sensor
- time
- 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.)
- Pending
Links
- 238000001514 detection method Methods 0.000 claims abstract description 105
- 230000010355 oscillation Effects 0.000 claims abstract description 55
- 230000006866 deterioration Effects 0.000 claims abstract description 37
- 239000007789 gas Substances 0.000 claims description 149
- 239000004065 semiconductor Substances 0.000 claims description 2
- 230000002829 reductive effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000007774 longterm Effects 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- 230000005856 abnormality Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000009412 basement excavation Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- 206010011906 Death Diseases 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【発明の詳細な説明】
＆ 発明の詳細な説明
〔産業上の利用分野〕
本発明は還元性ガスを検知するガス検知装置にかかわシ
、特に、長期にわたって高信頼度の検知を行うのに好適
なガス検知装置に関する。[Detailed Description of the Invention] & Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a gas detection device for detecting a reducing gas, and is particularly suitable for performing highly reliable detection over a long period of time. related to a gas detection device.
可燃性ガスのガス検知装置については、従来から種々の
提案がなされているが、被検知ガス以外の例えばアルコ
ール等の雑ガスにより誤動作、誤報を生じやすい問題が
あシ、さらに、長期の使用中にガスセンサの固有抵抗値
が低下してくるため、あらかじめ定めた警報レベルのま
まで使用していると１次第に設定時より低濃夏のガス漏
れでも警報を発するようになり、見掛は上はガスセンサ
の感度が鋭敏に変化したのと同等になシ、長期安定性お
よび信頼性の面で問題があった。Various proposals have been made for gas detection devices for combustible gases, but there are problems with malfunctions and false alarms due to miscellaneous gases other than the detected gas, such as alcohol, and furthermore, there are problems with long-term use. As the specific resistance value of the gas sensor decreases over time, if you continue to use the preset alarm level, it will gradually come to issue an alarm even when the gas leaks at a low concentration in the summer compared to when it was set. As well as the sharp changes in the sensitivity of the gas sensor, there were problems in terms of long-term stability and reliability.
これらの問題の解決策として、特公昭５Ｂ−７９４０号
公報、特公昭５Ｂ−４７６６３号公報に開示されている
ように、雑ガス酸化フィルタを用いる方策や。As a solution to these problems, as disclosed in Japanese Patent Publication No. 5B-7940 and Japanese Patent Publication No. 5B-47663, there is a method of using a miscellaneous gas oxidation filter.
特公昭５７−５３５３１号公報に開示されているように
、長期使用によりガスセンサの性能劣化が進行してくる
と、還元性ガスの存在しない空気雰囲気中において、ガ
スセンサの動作温度が定格動作温度近辺で発振現象を生
じる。そして、このガスセンサの出力信号の発振現象の
生じる動作温度が、ガスセンサ性能の経時変化による性
能劣化程度と関係があシ、性能劣化が少ないガスセンサ
では動作温度が低温時に発振が発生するが、定格動作温
度への昇温過程で消滅する。すなわち、ガスセンサの経
時劣化の程度と、ガスセンサの空気雰囲気中における発
振現象が消滅する（もしくは出現する）動作温度との間
に、相関関係があることを新たに見いだした。As disclosed in Japanese Patent Publication No. 57-53531, when a gas sensor's performance deteriorates due to long-term use, the operating temperature of the gas sensor may drop to around the rated operating temperature in an air atmosphere without reducing gas. Causes oscillation phenomenon. The operating temperature at which the oscillation phenomenon of the output signal of this gas sensor occurs is related to the degree of performance deterioration due to changes in gas sensor performance over time.In gas sensors with little performance deterioration, oscillation occurs when the operating temperature is low, but the rated operation It disappears during the process of increasing the temperature. That is, we have newly discovered that there is a correlation between the degree of deterioration of a gas sensor over time and the operating temperature at which the oscillation phenomenon of the gas sensor in the air atmosphere disappears (or appears).
本願発明者らは％またさらに、ガスセンサを。The inventors have further developed a gas sensor.
定格動作源！以下で、しかもガスセンサの出力に発揚が
生じるの低い動作温度に設定した場合、定格動作温度か
ら該一定の低い動作温度に温度を変化させた時点から、
ガスセンサの出力信号が発振を開始するまでの所要時間
が、ガスセンサの性能劣化程度と相関関係があることを
見いだした。Rated operating source! If the operating temperature is set to a temperature below which is low enough to cause a rise in the output of the gas sensor, from the point at which the temperature is changed from the rated operating temperature to the certain low operating temperature,
It has been found that the time required for the output signal of the gas sensor to start oscillating has a correlation with the degree of performance deterioration of the gas sensor.
前記目的は、上記の現象、特に最後に述べた現象を利用
して性能劣化程度を見付け、性能劣化程度に応じて検知
レベルを変えることによって、達成される。The above object is achieved by utilizing the above-mentioned phenomena, especially the last mentioned phenomenon, to find the degree of performance deterioration and changing the detection level depending on the degree of performance deterioration.
本発明は、ヒータ部の動作温度を変化させる手・段と、
ガスセンサの出力信号の発振の有無を検知する手段とを
設け、ヒータ部の動作温度を定格動作温度から該定格動
作温度より低いあらかじめ定めた複数の動作温度に順次
変化させて、所定の保持時間における各動作温度でのガ
スセンサの出力信号の発振の有無を検知することにより
、該ガスセンサの性能劣化の程度を判定し、その結果に
より、検知レベルをあらかじめ定めた値の一つく再設定
するものである。The present invention provides a means for changing the operating temperature of a heater section;
means for detecting the presence or absence of oscillation of the output signal of the gas sensor, and sequentially changes the operating temperature of the heater part from the rated operating temperature to a plurality of predetermined operating temperatures lower than the rated operating temperature, and By detecting the presence or absence of oscillation in the output signal of the gas sensor at each operating temperature, the degree of performance deterioration of the gas sensor is determined, and based on the results, the detection level is reset to one of the predetermined values. .
また、本発明では、ヒータ部の動作温度を定格動作温度
から変化させて、ガスセンサの出力信号の発振の有無を
検知する動作を行っている間、検知レベルを、定格動作
温度より低いあらかじめ定めた一定のもしくは各動作温
度に対応する第２の検知レベルに設定し、該期間中に発
生したガス漏れにも対処できるようにしている。Further, in the present invention, while the operating temperature of the heater part is changed from the rated operating temperature and the operation of detecting the presence or absence of oscillation of the output signal of the gas sensor is performed, the detection level is set to a predetermined level lower than the rated operating temperature. The second detection level is set to be constant or correspond to each operating temperature, so that it is possible to deal with gas leaks that occur during the period.
ヒータ部の動作温度を、還元性ガス検知のための定格動
作温度から、あらかじめ定めたこれより低い複数の動作
温度に順次変化させ、所定保持時間だけそれその温度に
保持したときのガスセンサの出力信号の発振開始の有無
を検出し、発振開始の有を検出した動作温度によってガ
スセンサの性能劣化の程度を判定し、その結果により、
還元性ガス検知レベルを第１の検知レベルの一つに順次
再設定することによ＃）％ ガスセンサの性能劣化の自
己補正が可能となる。そして、このような操作を、ガス
センサの使用開始時からあらかじめ定めた一定時間ごと
に行うことにより、長期にわたって高信頼性と高鞘度が
得られるとともに、性能劣化が非常圧進み寿命に達した
場合には、ガスセンサの寿命報知を行うこともできる。The output signal of the gas sensor when the operating temperature of the heater section is sequentially changed from the rated operating temperature for reducing gas detection to multiple predetermined lower operating temperatures and held at each temperature for a predetermined holding time. The degree of performance deterioration of the gas sensor is determined based on the operating temperature at which the oscillation start is detected, and based on the results,
By sequentially resetting the reducing gas detection level to one of the first detection levels, self-correction of performance deterioration of the gas sensor becomes possible. By performing such operations at predetermined intervals from the time the gas sensor is first used, high reliability and high coverage can be achieved over a long period of time. It is also possible to notify the lifespan of the gas sensor.
またさらに。And even more.
ガスセンサの性能劣化検出のための発振検出動作時にカ
ス漏れが発生した場合にも、ガスセンサの出力信号が一
定時間以上継続して第２の検知レベル以上となったとき
、還元性ガス検知の動作に戻して、ガス漏れに対処でき
るので、ガス漏れ検知ミスを生じることはない。Even if waste leakage occurs during the oscillation detection operation to detect performance deterioration of the gas sensor, when the output signal of the gas sensor continues to exceed the second detection level for a certain period of time, the reducing gas detection operation will be activated. Since the gas leak can be dealt with by returning the gas leak, there is no possibility of a gas leak detection error.
以下、本発明によるガス検知装置の一実施例を第１図な
いし第７図により説明する。第１図は該実施例の装置の
構成を示すブロック図、第２図、第６図および第４図は
本発明の装置に用いられるガスセンサの性能特性の一例
を示す特性図、第５図および第６図は該実施例の装置の
動作を示すタイムチャート、第７図は該実施例の装置の
動作を示すフローチャートである。An embodiment of the gas detection device according to the present invention will be described below with reference to FIGS. 1 to 7. FIG. 1 is a block diagram showing the configuration of the device of this embodiment, FIGS. 2, 6, and 4 are characteristic diagrams showing an example of the performance characteristics of the gas sensor used in the device of the present invention, and FIGS. FIG. 6 is a time chart showing the operation of the apparatus of this embodiment, and FIG. 7 is a flow chart showing the operation of the apparatus of this embodiment.
第１図において、１は半導体式のガスセンサ。In FIG. 1, 1 is a semiconductor type gas sensor.
２は該ガスセンサ１の還元性ガス検知用の感ガス部、３
は該感ガス部２を加熱するためのヒータ部、４は前記ガ
スセンサ１０感ガス特性を計測するための出力抵抗、５
は前記ガスセンサ１のヒータ部乙の動作温度を制御する
ためのヒータ制御部、６は前記ガスセンサ１の使用開始
から一定時間経過するごとに、該ヒータ制御部５により
前記ヒータ部３の動作温度を順次、あらかじめ定めた温
度に所定保持時間の量変化させる制御信号を送るための
タイマ部、７は前記ヒータ部３の動作温度が所定保持時
間ごとに変化するとき、該所定保持時間内に、前記ガス
センサ１の出力信号の発振開始の有無を検出するための
発振検知部％ ８は前記ガスセンサ１の周辺雰囲気温度
を検知するための温度検知部、９は該温度検知部８０信
号により前記所定保持時間を補正演算し、前記タイマ部
６に信号を送出するための補正演算部、１０は、前記ヒ
ータ部３の動作温度が所定保持時間変化するときごとに
、当該動作温度における前記発振検知部７の信号を記憶
し、発振開始を検知したときの当該動作温度に応じて、
前記ガスセンサ１の性能劣化を判定するための劣化判定
部、１１は、該劣化判定部１０の信号により、前記検知
レベルを、あらかじめ定めた第１の検印レベルの一つに
再設定するとともに、前記ガスセンサ１の出力信号の発
振開始の有無検出動作時には、あらかじめ定めた第２の
検知レベルに設定するための検知レベル制御部、１２は
ガスセンサ１の還元性カスによる出力信号を検出するた
めの信号検出部、１６は該信号検出ｍ１２の信号レベル
と、検知レベル制御部１１により設定された検知レベル
とを比較し、信号レベルが検知レベルを越えたとき信号
を出力する比較部、１４は該比較部１３の出力信号によ
り、ガス漏れおよびガスセンサの寿命を表示したｐ、警
報を発したシ、あるいはガス配管の元栓を閉止する等、
他の機器を制御しｆｃシするための制御部である。2 is a gas sensing part for detecting reducing gas of the gas sensor 1;
4 is a heater section for heating the gas sensing section 2; 4 is an output resistor for measuring the gas sensing characteristics of the gas sensor 10; 5 is a heater section for heating the gas sensing section 2;
Reference numeral 6 indicates a heater control unit for controlling the operating temperature of the heater unit B of the gas sensor 1, and 6 controls the operating temperature of the heater unit 3 by the heater control unit 5 every time a certain period of time elapses from the start of use of the gas sensor 1. A timer section 7 for sending a control signal to sequentially change the temperature to a predetermined amount for a predetermined holding time, when the operating temperature of the heater section 3 changes every predetermined holding time, An oscillation detection section for detecting whether or not the output signal of the gas sensor 1 starts to oscillate; 8 is a temperature detection section for detecting the temperature of the surrounding atmosphere of the gas sensor 1; 9 is a temperature detection section for detecting the predetermined holding time based on the temperature detection section 80 signal; A correction calculation unit 10 for performing a correction calculation and sending a signal to the timer unit 6 detects the oscillation detection unit 7 at the operating temperature every time the operating temperature of the heater unit 3 changes for a predetermined holding time. The signal is memorized, and depending on the operating temperature when the start of oscillation is detected,
A deterioration determination unit 11 for determining performance deterioration of the gas sensor 1 resets the detection level to one of predetermined first verification mark levels based on the signal from the deterioration determination unit 10, and At the time of detecting whether or not the output signal of the gas sensor 1 has started oscillating, a detection level controller 12 sets the detection level to a predetermined second detection level; A comparison section 16 compares the signal level of the signal detection m12 with the detection level set by the detection level control section 11, and outputs a signal when the signal level exceeds the detection level. 13 output signal indicates the gas leak and the life of the gas sensor, issues an alarm, closes the main valve of the gas piping, etc.
This is a control unit for controlling and performing fc operations on other devices.
第２図は、空気雰囲気中におけるガスセンサ１のヒータ
部３の動作温度を、ガス検知動作時の定格動作温度Ｔ、
から、ガスセンサ１の出力信号の発振検印動作時の動作
温度Ｔ２ （ただし’ｒ、＞Ｔ、）へと変化させたとき
のガスセンサ１の出力信号の発振特性の一例を示す特性
図である。ガスセンサ１のヒータ部の動作温度（ヒータ
温度）を定格動作温度Ｔ、から温ｋ Ｔ’＋へと変化さ
せると、ガスセンサ１の出力信号は定格動作温度Ｔ１時
の出力信号Ｖ。から急減するとともに、時間ｔＡ経過後
に発振を開始し。FIG. 2 shows the operating temperature of the heater section 3 of the gas sensor 1 in an air atmosphere, the rated operating temperature T during gas detection operation,
2 is a characteristic diagram showing an example of the oscillation characteristics of the output signal of the gas sensor 1 when the operating temperature T2 (where 'r,>T) is changed during the oscillation checking operation of the output signal of the gas sensor 1. When the operating temperature (heater temperature) of the heater section of the gas sensor 1 is changed from the rated operating temperature T to the temperature kT'+, the output signal of the gas sensor 1 becomes the output signal V at the rated operating temperature T1. It suddenly decreases from then, and starts oscillating after time tA has elapsed.
発振周期ｔＢで発振を縦紐する。Oscillation is vertically linked with an oscillation period tB.
第５図は、牛碑体式カスセンサのヒータ部の動作温度を
定格動作温度Ｔ、から低温側へ変化させた場合の、動作
温度（絶対温度の逆数で示しである）と、カスセンサの
出力信号の発振開始までの所要時間ｔｉ （逆数で示し
である）との関係の一例を示す特性−でおる。口中、特
性＋５．１６．１７お！１，１８Ｕ％ カスセンサの
使用開始からの経過時ＩＮ１．−テ、−，，−−−＋Ｗ
、ｙ＋＝五＋＋Ｌ１ｗｈ−１１ｍ４１ｒ＼＋ｎ’ｋｈＩ
ｉ式ンガス性能が劣化するにつれて、特性は１５→１６
−１７−１８へと変化してくるが、このような関係は新
たに見いだした現象である。すなわち、ガスセンサをガ
ス検知のための定格動作温度より低い温度で動作させた
場合に生じるガスセ／すの出力信号の極低周波（ｊｏ−
ｓ〜１０″″２Ｈｚ）の発振開始までの所要時間ｔえと
、ガスセンサの感ガス性能の劣化との間に相関関係があ
ることがわかった。空気雰囲気中におけるガスセンサの
ヒータ部の動作温度を定格動作温度Ｔ、から低温に変化
させたときから、ガスセンサの出力信号の発振開始まで
の所要時間ｔＡの逆数が一定値ｔ０となる動作温度は、
ガスセンサの感ガス性能の劣化が進行するにつれて。Figure 5 shows the operating temperature (shown as the reciprocal of the absolute temperature) and the output signal of the waste sensor when the operating temperature of the heater part of the cow monument type waste sensor is changed from the rated operating temperature T to the lower temperature side. The following is a characteristic showing an example of the relationship with the time required until the start of oscillation ti (indicated by a reciprocal number). In the mouth, characteristics +5.16.17! 1.18U% IN1 after the start of use of the waste sensor. −te, −,, −−−+W
,y+=5++L1wh-11m41r\+n'khI
As the i-type gas performance deteriorates, the characteristics change from 15 to 16.
-17-18, but this kind of relationship is a newly discovered phenomenon. In other words, the very low frequency (jo-
It has been found that there is a correlation between the time required until the start of oscillation at a frequency of s~10''2 Hz) and the deterioration of the gas sensing performance of the gas sensor. The operating temperature at which the reciprocal of the time tA required from when the operating temperature of the heater section of the gas sensor in an air atmosphere is changed from the rated operating temperature T to a low temperature until the output signal of the gas sensor starts oscillating becomes a constant value t0 is:
As the gas sensing performance of gas sensors continues to deteriorate.
例えば、第６図におけるｄ。１９からｄ、 ２０． ｄ
、 ２＋。For example, d in FIG. 19 to d, 20. d
, 2+.
ｄ、２２のように高温側へと変化する。そこで、ガスセ
ンサの出力信号の発振開始までの所要時間１Ａが一定と
なるヒータ部乙の動作温度の変化を検知することにより
、ガスセンサの性能劣化の程度を知ることができる。第
４図は、この発振開始までの所要時間ｔＡ（所要時間の
逆数ｊ／ｌＡで示してある）が一定となるガスセンサの
ヒータ部の動作温度と（絶対温度の逆数で示しである）
と、ガスセンサの特性劣化との関係を表わす特性の一例
を示したものである。そこで、第４図に示した特性２３
を用いることによ）、ガスセンサの性能劣化分ヲ自己補
正することができる。第４図に示した特性を利用してガ
スセンサの性能劣化を自己補正する方法としては１種々
のものが使用可能であるが、第１図に構成を示した本実
施例では、被検知ガス濃度の検知レベルを自動補正する
方法を用いた例を示している。d, changes to the high temperature side as shown in 22. Therefore, by detecting a change in the operating temperature of the heater part B, which makes the time 1A required until the output signal of the gas sensor starts oscillating constant, the degree of performance deterioration of the gas sensor can be known. Figure 4 shows the operating temperature of the heater section of the gas sensor at which the time tA (indicated by the reciprocal of the required time, j/lA) until the start of oscillation is constant, and the operating temperature (indicated by the reciprocal of the absolute temperature).
This figure shows an example of a characteristic representing the relationship between the characteristic deterioration of the gas sensor and the characteristic deterioration of the gas sensor. Therefore, the characteristic 23 shown in Figure 4
), it is possible to self-correct the performance deterioration of the gas sensor. Various methods can be used to self-correct the performance deterioration of the gas sensor using the characteristics shown in FIG. 4, but in this embodiment whose configuration is shown in FIG. An example using a method of automatically correcting the detection level is shown.
以下、第１図に示した本発明によるガス検知装置の動作
を、第５図のタイムチャートおよび第７区のフローチャ
ートを用いて説明する。まず、ヒータ制御部５により、
ガスセンサ１のヒータ部３を還元性ガス検知用の定格動
作温度ＴＩ （ｘ）で動作させる。また、還元性ガスの
検知レベルは、検知レベル制御部１１により、還元性ガ
スの検知すべきガス濃度に対応して、あらかじめ第１の
検知レベルの一つである検知レベルＬ、に設定しである
〇このとき、還元性ガスの、検知すべき濃度以下のガス
漏れが生じ１還元性ガス検出信号出力Ｖ、が生じた場合
にはｈ ｖ、＜ Ｌｌ＋ であるので、比較部１５は
信号を出力せず、制御部１４も信号を出力せず、従って
、表示や警報等の動作は生じない。次に、ガスセンサ１
の使用時間が、タイマ部６にあらかじめ設定しておいた
時間１＋（例えば数十〜数百時間）に到達すると、タイ
マ部６からヒータ制御部５および発振開始を検知するた
めの発振検知部７へそれぞれ制御信号が送出され、ヒー
タ制御部５はヒータ部３の動作温度をＴ、からＴ２へと
変化させ。Hereinafter, the operation of the gas detection device according to the present invention shown in FIG. 1 will be explained using the time chart of FIG. 5 and the flowchart of section 7. First, the heater control section 5
The heater section 3 of the gas sensor 1 is operated at the rated operating temperature TI (x) for detecting a reducing gas. Further, the detection level of the reducing gas can be set in advance to a detection level L, which is one of the first detection levels, by the detection level control unit 11 in accordance with the concentration of the reducing gas to be detected. Yes At this time, if the reducing gas leaks at a concentration lower than that to be detected and 1 reducing gas detection signal output V occurs, then h v < Ll+, so the comparator 15 outputs the signal. There is no output, and the control unit 14 also does not output a signal, so no display or alarm operation occurs. Next, gas sensor 1
When the usage time reaches the time 1+ (for example, several tens to hundreds of hours) set in advance in the timer section 6, the timer section 6 sends the heater control section 5 and the oscillation detection section 7 for detecting the start of oscillation. A control signal is sent to each of them, and the heater control section 5 changes the operating temperature of the heater section 3 from T to T2.
同時に１発振検知部７はガスセンサ１の出力信号の発振
開始検知動作を始める。補正演算部９は、温度検知部８
（例えばサーミスタ等）からの周辺雰囲気温度に対応し
た出力信号により、あらかじめ設定された基準温度（例
えば２５℃）への補正係数ｋを演算するとともに、ヒー
タ部Ｓの動作温度をＴ２に保持する所定保持時間ｔ２＝
に−ｔ、を演算し、タイマ部６に入力する０ヒ一タ部６
の動作温度Ｔ２における該所定保持時間ｔ２内に、ガス
センサ１の出力信号の発振が生ぜず、前記発振検知部７
が発振を検印しなかったとすると、ヒータ制御部５は所
定保持時間ｔ２経過後に動作温度をＴ、に戻し、安定動
作状態に達する時間１３（例えば十分量程度）経過後に
、ヒータ制御部５はタイマ部乙の制御信号により、ヒー
タ部３の動作温度をＴ５（ただしＴ。At the same time, the one-oscillation detection section 7 starts the operation of detecting the start of oscillation of the output signal of the gas sensor 1. The correction calculation unit 9 includes a temperature detection unit 8
Based on an output signal corresponding to the ambient ambient temperature from a thermistor (for example, a thermistor, etc.), a correction coefficient k to a preset reference temperature (for example, 25°C) is calculated, and a predetermined value is set to maintain the operating temperature of the heater section S at T2. Holding time t2=
-t, and inputs it to the timer section 6.
During the predetermined holding time t2 at the operating temperature T2, oscillation of the output signal of the gas sensor 1 does not occur, and the oscillation detection section 7
If no oscillation is detected, the heater control unit 5 returns the operating temperature to T after the predetermined holding time t2 has elapsed, and after the time 13 (for example, about a sufficient amount) for reaching a stable operating state has elapsed, the heater control unit 5 sets the timer The operating temperature of the heater section 3 is set to T5 (however, T.
＞ Ｔ、 ＞Ｔ２）に変化させる。動作温度Ｔ、での所
定保持時間ｔ２経過前に、前記発振検知部７がガスセン
サ１の出力信号の発振を検知したとする。次いで、前記
と同様に、ヒータ制御部５はタイマ部乙の制御信号によ
）、動作温度を定格動作温度Ｔ、に時間１Ｓの間復帰さ
せた後、動作温度をＴ、（ただしＴ、＞Ｔ４＞Ｔ、 ＞
Ｔ２ ） に所定保持時間ｔ２だけ変化させ。>T, >T2). Assume that the oscillation detection section 7 detects oscillation of the output signal of the gas sensor 1 before the predetermined holding time t2 at the operating temperature T has elapsed. Next, in the same manner as described above, the heater control section 5 returns the operating temperature to the rated operating temperature T for a period of time 1S (based on the control signal from the timer section B), and then returns the operating temperature to T, (where T, >T4>T,>
T2) is changed by a predetermined holding time t2.
該所定保持時間内に、発振検印部７が発振開始を検知し
たとする。同様に動作温度をＴ、 （Ｔ、 ＞Ｔ。It is assumed that the oscillation check mark section 7 detects the start of oscillation within the predetermined holding time. Similarly, the operating temperature is T, (T, >T.
）Ｔ４＞Ｔ、＞Ｔ２）に変化させたときも、前記所定保
持時間ｔ２内に、発振検印部７が発振開始を検知したと
する。すると、劣化判定部１０は、各動作温度Ｔ２．
Ｔ、、 Ｔ、およびＴ５における発振検知部７の発振開
始検印の再熱を順次記憶するとともに、この場合は、所
定保持時間ｔ２以内に、動作温度Ｔ２では発振がなかっ
たが、動作温度ＩＴＴ４およびＴ５では発振があったこ
とから、ガスセンサの性能劣化は少ないと判定し、還元
性ガスの第１の検知レベルはり、のままで変更させない
。次いで、還元性ガスの、検知すべき濃度以上のガス漏
れが生じ、還元性ガス検出信号ｖ２が生じると、ｖ２≧
Ｌ、であるので、比較部１６および制御部１４は信号を
出力し、表示や警報により異常を報知する。)T4>T,>T2), it is assumed that the oscillation check mark unit 7 detects the start of oscillation within the predetermined holding time t2. Then, the deterioration determination unit 10 determines that each operating temperature T2.
The reheating of the oscillation start verification mark of the oscillation detection unit 7 at T, T, and T5 is sequentially memorized. Since oscillation occurred at T5, it was determined that there was little deterioration in the performance of the gas sensor, and the first detection level of the reducing gas remained unchanged and was not changed. Next, when the reducing gas leaks at a concentration higher than that to be detected and the reducing gas detection signal v2 is generated, v2≧
L, so the comparison unit 16 and the control unit 14 output a signal and notify the abnormality by a display or an alarm.
続いて、経過時間がさらにｔ、に到達すると、上記と同
様に、タイマ部６はヒータ制御部５に制御信号を送出し
、ヒータ部３の動作温度をＴ、からＴ２へと変化させる
。一方、補正演算部９は、温要検知部８の信号により補
正係数を演算し、尚該動作温度Ｔ２における所定保持時
間ｔ２を演算し、タイマ部６〜入力する。動作温度Ｔ２
における該所定保持時間ｔ２内に、ガスセンサ１の出力
信号の発振が生ぜず、前記発振検知部７が尭碌を検印し
なかったとする。次いで、定格動作温度Ｔ、でｔ３時間
動作後、動作温度をＴ、に変化させ、発振検知を行う。Subsequently, when the elapsed time further reaches t, the timer section 6 sends a control signal to the heater control section 5 to change the operating temperature of the heater section 3 from T to T2, similarly to the above. On the other hand, the correction calculation section 9 calculates a correction coefficient based on the signal from the temperature detection section 8, and also calculates a predetermined holding time t2 at the operating temperature T2, and inputs it to the timer section 6. Operating temperature T2
Assume that the oscillation of the output signal of the gas sensor 1 does not occur within the predetermined holding time t2 in , and the oscillation detection section 7 does not detect the yakusen. Next, after operating for t3 hours at the rated operating temperature T, the operating temperature is changed to T, and oscillation detection is performed.
同様に、動作温度Ｔ４．Ｔ、における発振検知を行い、
その結果、所定保持時間ｔ２内で、動作温度Ｔ、のとき
発振検知がなく、Ｔ４およびＴ６のとき発振検知があっ
たとすると、前記劣化判定部１０はガスセンサ１の性能
劣化があると判定して、性能劣化程度に応じた制御信号
を検知レベル制御部１１に送シ、検知レベル制御部１１
は、還元性ガスの第１の検知レベルを、ガスセンサの特
性劣化の程度に応じて、あらかじめ設定しである検知レ
ベルＬ２（Ｌ２＞Ｌ＋）に変更、再設定する。その後、
検知濃度以下のガス漏れが生じ、還元性ガス検出信号出
力ｖ３が生じたとする。また、このＶ、は、ガスセンサ
の特性劣化による固有抵抗値の低下のために、検知濃度
以下のガス漏れにもかかわらず、前記した検知濃度以下
のガス漏れ時のガス検出信号出力ｖ２と同等（Ｖｓ ＃
Ｖ２）の出力であったとする。しかし、今回の場合は
、ガスセンサの特性劣化の程度に応じて、第１の検知レ
ベルがすてにり、かうＬ２（ｘ、２＞Ｌ、 ）に再設定
されておシ、かつＶ、＜Ｌ、 であるので、比較部１
３および制御部１４は出力を生ぜず、従って、経時劣化
による検知誤差を補正できたことになる。次いで、検知
濃度以上のガス漏れが生じ、再設定された第１の検知レ
ベルＬ２より大きい検出信号出力が生じると、比較部１
３を介し制御部１４は信号を出力し、表示、警報により
異常を知らせるか、またはガス供給用の元栓を閉止させ
る。Similarly, operating temperature T4. Perform oscillation detection at T,
As a result, if within the predetermined holding time t2, no oscillation is detected at the operating temperature T, and oscillations are detected at T4 and T6, the deterioration determining section 10 determines that the performance of the gas sensor 1 has deteriorated. , sends a control signal according to the degree of performance deterioration to the detection level control section 11;
The first detection level of the reducing gas is changed and reset to the preset detection level L2 (L2>L+) according to the degree of characteristic deterioration of the gas sensor. after that,
Assume that a gas leakage below the detected concentration occurs and a reducing gas detection signal output v3 is generated. In addition, this V is equivalent to the gas detection signal output v2 at the time of gas leakage below the detection concentration, even though the gas leakage is below the detection concentration, due to the decrease in the specific resistance value due to the deterioration of the characteristics of the gas sensor ( Vs #
Suppose that the output is V2). However, in this case, depending on the degree of deterioration of the characteristics of the gas sensor, the first detection level is discarded and reset to L2 (x, 2>L, ), and V<< L, so comparison part 1
3 and the control unit 14 do not produce any output, and therefore the detection error due to deterioration over time has been corrected. Next, when a gas leak with a concentration higher than the detected concentration occurs and a detection signal output larger than the reset first detection level L2 occurs, the comparator 1
3, the control unit 14 outputs a signal to notify an abnormality through a display or an alarm, or closes the main valve for gas supply.
次に、長期間の使用によりガスセンサの性能劣化がさら
に進行し、ヒータ部３の動作温度がＴ２゜Ｔ、またはＴ
４のとき、所定保持時間ｔ２内でガスセンサ１の出力信
号に発振が検知されず、動作温度Ｔ５のとき発振が検知
されたとする。このとき、劣化判定部１０は性能劣化が
非常に進行したと判定し、検知レベル制御部１１は、還
元性ガスの第１の検知レベルをＬｓ （Ｌｓ ＞Ｌ２
）に変更、再設定して、還元性ガスのガス漏れ検知を続
行する。ちるいは、ヒータ部５の動作温度がＴ５のとき
しか、所定保持時間ｔ２内に発掘が検出されなかった場
合は、このガスセンサが寿命に到達したとして、第７図
のフローチャート中に破線で示したように、ガスセンサ
交換用の寿命信号を出力し、表示または警報を発するよ
うにしてもよい。Next, due to long-term use, the performance deterioration of the gas sensor further progresses, and the operating temperature of the heater section 3 reaches T2°T or T2°T.
4, oscillation is not detected in the output signal of the gas sensor 1 within the predetermined holding time t2, and oscillation is detected at the operating temperature T5. At this time, the deterioration determination unit 10 determines that the performance deterioration has progressed significantly, and the detection level control unit 11 sets the first detection level of the reducing gas to Ls (Ls > L2
) and reset it to continue detecting reducing gas leaks. In other words, if excavation is not detected within the predetermined holding time t2 only when the operating temperature of the heater section 5 is T5, it is assumed that this gas sensor has reached the end of its life, as indicated by the broken line in the flowchart of FIG. As described above, an end-of-life signal for gas sensor replacement may be output, and a display or alarm may be issued.
次に、ヒータ部３の動作温度が定格動作温度Ｔ。Next, the operating temperature of the heater section 3 is the rated operating temperature T.
からＴ２またはＴ３またはＴ４またはＴ、に変化し、発
振検知動作中にガス漏れが生じた場合の動作について、
第６図および第７図により説明する。ガスセンサ１の使
用時間があらかじめ設定しておいた時間ｔ１に到達する
と、上記のように、タイマ部６からヒータ制御部５およ
び発振検知部７へそれぞれ制御信号が所定保持時間ｔ２
の間送出され、ヒータ制御部５はヒータ部３の動作温度
をＴ、からＴ２へと変化させ、同時に、発振検知部７が
発振検知動作を開始する。また同時に、還元性ガスの検
知レベルを第１の検知レベル（前記り、、Ｌ２等）から
、あらかじめ定めである第２の検知レベルＭに切り換え
る。この第２の検知レベルＭは１発振検知部作時にガス
漏れが生じた場合の検知用のもので、定格動作温度で動
作時の検知レベルである第１の検知レベルＬ、、 Ｌ２
． Ｌ、より小さい値に設定しである。Regarding the operation when the gas leakage occurs during the oscillation detection operation after changing from T2 or T3 or T4 or T,
This will be explained with reference to FIGS. 6 and 7. When the usage time of the gas sensor 1 reaches the preset time t1, as described above, control signals are sent from the timer section 6 to the heater control section 5 and the oscillation detection section 7 for a predetermined holding time t2.
The heater control section 5 changes the operating temperature of the heater section 3 from T to T2, and at the same time, the oscillation detection section 7 starts an oscillation detection operation. At the same time, the detection level of the reducing gas is switched from the first detection level (described above, L2, etc.) to the predetermined second detection level M. This second detection level M is for detecting gas leakage during one-oscillation detection operation, and the first detection level L, L2 is the detection level when operating at the rated operating temperature.
．． L, set to a smaller value.
上記のようにして動作温度Ｔ、で動作中にガス漏れが生
じた場合、還元性ガス検出信号Ｖ、が生じ、一定時間以
上継続的に％＞Ｍであるとすると、ヒータ制御部５は比
較部１５からの信号により、発振検知動作に関係なく優
先的に、ヒータ部３の動作温度を還元性ガス検知時の温
度である定格動作源ｔｉ Ｔ ＋に復帰させ、同時に還
元性ガス検知レベルを第１の検知レベルに復帰させる。When a gas leak occurs during operation at the operating temperature T, as described above, a reducing gas detection signal V is generated, and assuming that %>M continues for a certain period of time or more, the heater control unit 5 The signal from the section 15 causes the operating temperature of the heater section 3 to return to the rated operating source ti T +, which is the temperature at the time of detecting the reducing gas, preferentially, regardless of the oscillation detection operation, and at the same time, the reducing gas detection level is increased. Return to the first detection level.
このとき、還元性ガス検出信号出力Ｖ、が第１の検知レ
ベル（例えばり、）を越えていれば、比較部１３は信号
を出力し、制御部１４も信号を出力し、表示、警報等に
より異常を知らせるか、またはガス供給の元栓を閉止す
る等地の機器を制御する。At this time, if the reducing gas detection signal output V exceeds the first detection level (for example, control local equipment, such as notifying an abnormality or closing the main valve of the gas supply.
なお、上記実施例では、発振検知時におけるガス漏れ検
知用の第２の検知レベルを、ヒータ部６の動作温度を段
階的に変化させているにもかかわらず、一定のレベルＭ
とした場合について説明したが、発振検出動作時のヒー
タ部３の動作温度の段階的変化に対応した検九レベルを
それぞれ設定してもよいことは言うまでもない。In the above embodiment, the second detection level for detecting gas leakage at the time of oscillation detection is set at a constant level M, although the operating temperature of the heater section 6 is changed stepwise.
Although the case has been described, it goes without saying that the test levels corresponding to the stepwise changes in the operating temperature of the heater section 3 during the oscillation detection operation may be set.
また、上記実施例では、ヒータ制御部５によるヒータ部
６の動作源＃を低温側から高温側へ（Ｔ２→Ｔ、→Ｔ４
−Ｔ、）ｉ化させて、各動作温度における所定保持時間
ｔ２内のガスセンサ１の出力信号の発振の有無を検知す
る方式について説明したが、逆にヒータ部３の動作温度
を定格動作温度に近い高温側から低温側へ（Ｔｓ ＝Ｔ
ａ −Ｔｉ ＝Ｔ２）と変化させ、各動作温度における
発掘の有無を検知する方式を用いても、上記実施例の場
合と同様にガスセンサの性能劣化を自動補正し、あるい
は寿命検知できることは明らかである。Further, in the above embodiment, the operation source # of the heater section 6 by the heater control section 5 is changed from the low temperature side to the high temperature side (T2→T, →T4
-T, )i and detects the presence or absence of oscillation of the output signal of the gas sensor 1 within a predetermined holding time t2 at each operating temperature. from the near high temperature side to the low temperature side (Ts = T
It is clear that even if a method is used in which the presence or absence of excavation is detected at each operating temperature by changing a - Ti = T2), it is possible to automatically correct the performance deterioration of the gas sensor or detect the life of the gas sensor, as in the case of the above embodiment. be.
本発明によれば、ガス検知装置において、実使用状態の
ｉまで、ガスセンサの性能劣化を任意の時間ごとに自己
チェックし、特性劣化の程度に応じた補正を自動的に行
わせることができるとともに寿命検知ができるので、長
期にわたｐ高信頼性、高′ａ度を保持した誤動作の生じ
ないガス検知装置が得られる。According to the present invention, in a gas detection device, performance deterioration of the gas sensor can be self-checked at arbitrary time intervals up to i in the actual usage state, and correction can be automatically performed according to the degree of characteristic deterioration. Since lifetime detection is possible, a gas detection device that maintains high reliability and high a degree over a long period of time and does not cause malfunctions can be obtained.
第１図は本発明によるガス検知装置の一実施例の構成を
示すブロック図、第２図、第３図および第４図は本発明
の装置に用いられるガスセンサの性能特性の一例を示す
特性図、第５図および第６図は第１因の装置の動作を示
すタイムチャート、第７因は第１図の装置の動作を示す
フローチャートである。
１・・・ガスセンサ、２・・・感ガス部、３・・・ヒー
タ部、４・・・出力抵抗、５・・・ヒータ制御部、６・
・・タイマ部、７・・・発振検知部、８・・・温度検知
部、９・・・補正演算部、１０・・・劣化判定部、１１
・・・検知レベル制御部、１２・・・信号検出部、１３
・・・比較部、１４・・・制御部。FIG. 1 is a block diagram showing the configuration of an embodiment of the gas detection device according to the present invention, and FIGS. 2, 3, and 4 are characteristic diagrams showing an example of the performance characteristics of the gas sensor used in the device of the present invention. , FIGS. 5 and 6 are time charts showing the operation of the device for the first factor, and a flowchart for the seventh factor showing the operation of the device in FIG. 1. DESCRIPTION OF SYMBOLS 1... Gas sensor, 2... Gas sensing part, 3... Heater part, 4... Output resistance, 5... Heater control part, 6...
...Timer section, 7... Oscillation detection section, 8... Temperature detection section, 9... Correction calculation section, 10... Deterioration determination section, 11
... detection level control section, 12 ... signal detection section, 13
... Comparison section, 14... Control section.
Claims (1)
する半導体式のガスセンサと、該ガスセンサの出力信号
を検出する信号検出部と、該信号検出部からの検出信号
のレベルを設定された検知レベルと比較し、その結果に
より、表示もしくは発報または他の機器を制御するため
の制御部に信号を出力する比較部とで構成される還元性
ガス用のガス検知装置であって、前記ヒータ部の動作温
度を変化させる手段と、前記ガスセンサの出力信号の発
振の有無を検知する手段とを設け、前記ヒータ部の動作
温度を定格動作温度から該定格動作温度より低いあらか
じめ定めた複数の動作温度に順次変化させて、所定の保
持時間における各動作温度での前記ガスセンサの出力信
号の発振の有無を検知することにより、該ガスセンサの
性能劣化の程度を判定し、その結果により、前記検知レ
ベルをあらかじめ定めた値の一つに再設定することを特
徴とするガス検知装置。 ２、特許請求の範囲第１項に記載のガス検知装置におい
て、ヒータ部の動作温度を定格動作温度から変化させて
、ガスセンサの出力信号の発振の有無を検知する動作を
行っている間、検知レベルを、前記定格動作温度より低
いあらかじめ定めた一定もしくは各動作温度に対応する
第２の検知レベルに設定することを特徴とするガス検知
装置。[Claims] 1. A semiconductor gas sensor having a gas sensing section and a heater section that heats the gas sensing section, a signal detection section that detects an output signal of the gas sensor, and a detection signal from the signal detection section. A gas detection system for reducing gases that consists of a comparison unit that compares the level of the gas with a set detection level and outputs a signal to a control unit for displaying, issuing alarms, or controlling other equipment based on the results. The apparatus includes means for changing the operating temperature of the heater section, and means for detecting the presence or absence of oscillation of the output signal of the gas sensor, and the operating temperature of the heater section is changed from the rated operating temperature to the rated operating temperature. Determining the degree of performance deterioration of the gas sensor by sequentially changing to a plurality of low predetermined operating temperatures and detecting the presence or absence of oscillation of the output signal of the gas sensor at each operating temperature during a predetermined holding time, A gas detection device characterized in that the detection level is reset to one of predetermined values based on the result. 2. In the gas detection device according to claim 1, while the operating temperature of the heater section is changed from the rated operating temperature and the operation of detecting the presence or absence of oscillation of the output signal of the gas sensor is performed, the detection is performed. A gas detection device characterized in that the level is set to a predetermined constant level lower than the rated operating temperature or a second detection level corresponding to each operating temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13361786A JPS62291557A (en) | 1986-06-11 | 1986-06-11 | Gas detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13361786A JPS62291557A (en) | 1986-06-11 | 1986-06-11 | Gas detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62291557A true JPS62291557A (en) | 1987-12-18 |
Family
ID=15109004
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13361786A Pending JPS62291557A (en) | 1986-06-11 | 1986-06-11 | Gas detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62291557A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02171647A (en) * | 1988-11-02 | 1990-07-03 | Vaisala Oy | Measurement method and sensor for measuring relative density of gas or steam |
-
1986
- 1986-06-11 JP JP13361786A patent/JPS62291557A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02171647A (en) * | 1988-11-02 | 1990-07-03 | Vaisala Oy | Measurement method and sensor for measuring relative density of gas or steam |
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