JP3523323B2 - Gas detection circuit using contact combustion type gas sensor - Google Patents
Gas detection circuit using contact combustion type gas sensorInfo
- Publication number
- JP3523323B2 JP3523323B2 JP09460094A JP9460094A JP3523323B2 JP 3523323 B2 JP3523323 B2 JP 3523323B2 JP 09460094 A JP09460094 A JP 09460094A JP 9460094 A JP9460094 A JP 9460094A JP 3523323 B2 JP3523323 B2 JP 3523323B2
- Authority
- JP
- Japan
- Prior art keywords
- output terminal
- resistor
- detection circuit
- gas
- compensating element
- Prior art date
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Description
【0001】[0001]
【産業上の利用分野】本発明は、ガス漏れ警報器などに
用いられている接触燃料式ガスセンサを用いたガス検知
回路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 detection circuit using a contact fuel type gas sensor used in a gas leak alarm or the like.
【0002】[0002]
【従来の技術】今日、化学プラントなどの工場、又は、
工事現場、更には家庭用などのガス漏れ警報器や一酸化
炭素検出器として、接触燃焼式ガスセンサ(例えば特開
平4−140656号)が多用されている。この接触燃
焼式ガスセンサを用いたガス検知回路は、図6に示すよ
うに、大気中のガスと接触して抵抗値が変化する検知素
子21と、この検知素子21と同一構造とされ、検知素子21
の抵抗値に近似した抵抗値を有して密封されている補償
素子23とを直列として第1入力端子11と第2入力端子13
との間に挿入してこの第1入力端子11及び第2入力端子
13から所定の電圧を印加することとし、検知素子21に設
けられているガス感応体が大気中の可燃性ガスと反応し
て燃焼し、ガス感応体内部のコイル抵抗値が変化するこ
とを利用してガス検出を行うものである。2. Description of the Related Art Today, factories such as chemical plants, or
A contact combustion gas sensor (for example, Japanese Patent Laid-Open No. 4-140656) is widely used as a gas leak alarm and a carbon monoxide detector for construction sites, households and the like. As shown in FIG. 6, a gas detection circuit using this contact combustion type gas sensor has a detection element 21 that has a resistance value that changes in contact with gas in the atmosphere and a detection element 21 that has the same structure as the detection element 21. twenty one
The first input terminal 11 and the second input terminal 13 are connected in series with a compensating element 23 which has a resistance value close to that of
Insert between the first input terminal 11 and the second input terminal
By applying a predetermined voltage from 13, the gas sensor provided in the detection element 21 reacts with combustible gas in the atmosphere and burns, and the coil resistance value inside the gas sensor changes. Then, the gas is detected.
【0003】そしてこの検知素子21及び補償素子23と並
列にブリッジ抵抗器とする第1固定抵抗器25及び第2固
定抵抗器27を設けてブリッジ回路を構成し、検知素子21
と補償素子23との接続点を第1出力端子15に接続し、更
に第1固定抵抗器25と第2固定抵抗器27との間に挿入さ
れた調整抵抗器33の摺動端子を第2出力端子17に接続
し、第1出力端子15と第2出力端子17との間の電位差に
より大気中に一酸化炭素やその他の可燃性ガスが存在す
ることを検出するものである。A bridge circuit is constructed by providing a first fixed resistor 25 and a second fixed resistor 27, which are bridge resistors, in parallel with the sensing element 21 and the compensating element 23 to form a bridge circuit.
And the compensation element 23 are connected to the first output terminal 15, and the sliding terminal of the adjusting resistor 33 inserted between the first fixed resistor 25 and the second fixed resistor 27 is connected to the second output terminal 15. It is connected to the output terminal 17 and detects the presence of carbon monoxide and other combustible gases in the atmosphere based on the potential difference between the first output terminal 15 and the second output terminal 17.
【0004】なお、このガス検知回路の他の回路構成と
しては、図7に示すように、ブリッジ抵抗器としての第
1固定抵抗器25と第2固定抵抗器27とを直列に配置し、
この直列とした第1固定抵抗器25及び第2固定抵抗器27
と並列に調整抵抗器35を設け、第1固定抵抗器25と第2
固定抵抗器27との接続点及び調整抵抗器35の摺動端子を
第2出力端子17に接続した回路とするものもあり、更
に、検知素子21の抵抗値と補償素子23の抵抗値とを合わ
せるために、補償素子23と並列にトリミング抵抗器を接
続配置するものなどがある。As another circuit configuration of this gas detection circuit, as shown in FIG. 7, a first fixed resistor 25 and a second fixed resistor 27 as bridge resistors are arranged in series,
The first fixed resistor 25 and the second fixed resistor 27 connected in series
An adjustment resistor 35 is provided in parallel with the first fixed resistor 25 and the second fixed resistor 25.
There is also a circuit in which the connection point with the fixed resistor 27 and the sliding terminal of the adjusting resistor 35 are connected to the second output terminal 17, and further, the resistance value of the sensing element 21 and the resistance value of the compensating element 23 are set. For matching, there is one in which a trimming resistor is connected and arranged in parallel with the compensating element 23.
【0005】そして、この検知素子21を用いた検知回路
の使用方法としては、調整抵抗器33,35を調整しておく
ことにより、第1出力端子15と第2出力端子17との間の
設定電位差を零としておき、第1出力端子15及び第2出
力端子17間の電位差が所定値以上となったときにガス漏
れ警報を発するようにした検出器や、調整抵抗器33,35
を調整しておくことにより、第1出力端子15と第2出力
端子17との間に所定の電位差が生じるように設定してお
き、第1出力端子15と第2出力端子17との間の電位差が
なくなるゼロクロス時を検出することによりガス漏れ警
報を発するようにした検出器がある。As a method of using the detection circuit using the detection element 21, the adjustment resistors 33 and 35 are adjusted to set between the first output terminal 15 and the second output terminal 17. A detector that adjusts the potential difference to zero and issues a gas leak alarm when the potential difference between the first output terminal 15 and the second output terminal 17 becomes a predetermined value or more, and the adjustment resistors 33, 35.
Is adjusted so that a predetermined potential difference is generated between the first output terminal 15 and the second output terminal 17, and the voltage between the first output terminal 15 and the second output terminal 17 is adjusted. There is a detector that issues a gas leak alarm by detecting the time of zero cross when the potential difference disappears.
【0006】[0006]
【発明が解決しようとする課題】前述のように、検知素
子と補償素子とは抵抗値の近似したものを組み合わせ、
調整抵抗器を調整することによりブリッジ回路の出力を
零又は小さな所定の値に設定するようにしているも、電
源電圧の変動や周囲の温度変化により第1出力端子と第
2出力端子との電位差である設定電位差が変動し、誤動
作により警報が発せられたり、ガス漏れが生じていても
警報が発せられないなど、適切な作動状態を維持できな
いこともあった。As described above, as the sensing element and the compensating element, those having similar resistance values are combined,
Although the output of the bridge circuit is set to zero or a small predetermined value by adjusting the adjustment resistor, the potential difference between the first output terminal and the second output terminal may occur due to fluctuations in the power supply voltage or ambient temperature changes. The set potential difference fluctuates and an alarm is issued due to a malfunction, or even if a gas leak occurs, an alarm may not be issued, and an appropriate operating state may not be maintained.
【0007】又、このような電圧変動や温度変化により
適切な作動状態が維持できなくなることをなくすため、
検知素子と補償素子とは抵抗値の近似したものを組み合
わせるのみでなく、温度特性の近似した検知素子と補償
素子とを組み合わせるようにすることがあるも、使用す
る素子が限定されることとなり、ガス検知回路ひいては
ガス検出器の量産性を低くする欠点があった。Further, in order to prevent a situation in which an appropriate operating state cannot be maintained due to such voltage fluctuation and temperature change,
The sensing element and the compensating element may not only be combined with those having an approximate resistance value, but may be combined with a sensing element and a compensating element having an approximate temperature characteristic, but the elements to be used are limited, There is a drawback that the mass production of the gas detection circuit and eventually the gas detector is reduced.
【0008】[0008]
【課題を解決するための手段】本発明は、接触燃焼式ガ
スセンサの検知素子と補償素子とを直列として2入力端
子間に配置し、検知素子と補償素子との接続点を第1出
力端子に接続し、第1出力端子と2個の入力端子間に各
々調整抵抗器を配置して検知素子及び補償素子に各々並
列とした抵抗器を設けると共に、2個の入力端子間に第
1固定抵抗器及び第2固定抵抗器の2個の抵抗器を直列
に配置し、第1固定抵抗器と第2固定抵抗器との接続点
を第2出力端子に接続したガス検知回路とする。According to the present invention, a sensing element and a compensating element of a catalytic combustion type gas sensor are arranged in series between two input terminals, and a connection point between the sensing element and the compensating element is a first output terminal. Connected to each other, an adjusting resistor is arranged between the first output terminal and the two input terminals, and a resistor is provided in parallel with each of the sensing element and the compensating element, and the first fixed resistance is provided between the two input terminals. And a second fixed resistor are arranged in series, and a connection point between the first fixed resistor and the second fixed resistor is connected to the second output terminal to form a gas detection circuit.
【0009】尚、検知素子及び補償素子と各々並列に抵
抗器を接続するに際し、検知素子と補償素子との接続点
を調整抵抗器の中間摺動端子に接続して調整抵抗器の一
部を検知素子と並列に、及び、調整抵抗器の他の一部を
補償素子と並列とするようにして検知素子及び補償素子
と並列に調整抵抗器を設けることが有る。When connecting a resistor in parallel with each of the sensing element and the compensating element, the connection point between the sensing element and the compensating element is connected to the intermediate sliding terminal of the regulating resistor to partially connect the regulating resistor. An adjusting resistor may be provided in parallel with the sensing element and in parallel with the compensating element such that another part of the adjusting resistor is in parallel with the sensing element and the compensating element.
【0010】[0010]
【作 用】本発明は、2個の入力端子間に直列に検知素
子と補償素子とを設け、且つ、この入力端子間に2個の
固定抵抗器を直列に設けることによりブリッジ回路を形
成し、固定抵抗器の中点となる抵抗器相互間の接続点を
第2出力端子としている故、第2出力端子の出力電圧を
基準として検知素子の抵抗値変化による出力電圧の変化
を検出することによりガスの発生を検知することができ
る。[Operation] The present invention forms a bridge circuit by providing a sensing element and a compensating element in series between two input terminals, and two fixed resistors in series between these input terminals. Since the connection point between the resistors, which is the middle point of the fixed resistor, is the second output terminal, it is necessary to detect the change in the output voltage due to the change in the resistance value of the sensing element with reference to the output voltage of the second output terminal. Thus, the generation of gas can be detected.
【0011】又、検知素子と補償素子との接続点に接続
される第1出力端子と2個の入力端子との間に各々調整
抵抗器を配置している故、調整抵抗器を調節することに
より第1出力端子の出力電圧を設定調整することができ
る。尚、検知素子と補償素子との接続点を調整抵抗器の
摺動端子に接続すれば、調整抵抗器の摺動接点を移動さ
せることにより第1出力端子の出力電圧を調整する際の
調整を容易に行うことができる。Further, since the adjusting resistors are arranged between the first output terminal and the two input terminals which are connected to the connection point between the sensing element and the compensating element, the adjusting resistors are adjusted. Thus, the output voltage of the first output terminal can be set and adjusted. If the connection point between the sensing element and the compensating element is connected to the sliding terminal of the adjusting resistor, the sliding contact of the adjusting resistor is moved to adjust the output voltage of the first output terminal. It can be done easily.
【0012】[0012]
【実施例】本発明の実施例は、図1に示すように、第1
入力端子11と第2入力端子13との間に抵抗値の等しい第
1固定抵抗器25と第2固定抵抗器27とを直列に配置して
第1固定抵抗器25と第2固定抵抗器27との接続点を第2
出力端子17に接続し、又、第1入力端子11と第2入力端
子13との間に接触燃焼式ガスセンサとしての検知素子21
及び、この検知素子21と抵抗値の近似した補償素子23を
直列として接続し、この検知素子21と補償素子23との接
続点を第1出力端子15に接続すると共に、第1入力端子
11と第2入力端子13との間に2KΩの調整抵抗器31を挿
入し、この調整抵抗器31の中間摺動端子をも第1出力端
子15に接続した回路とし、調整抵抗器31の摺動接点位置
を調節することにより第1出力端子15の電位を第2出力
端子17の電位よりも僅かに低く設定しておくものであ
り、空気中にガスが発生すると検知素子21の抵抗値が増
大し、第1出力端子15の電位が第2出力端子17の電位と
等しくなると警報を発するようにしたガス漏れ警報器の
ガス検知回路とするものである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of the present invention is, as shown in FIG.
A first fixed resistor 25 and a second fixed resistor 27 having the same resistance value are arranged in series between the input terminal 11 and the second input terminal 13, and the first fixed resistor 25 and the second fixed resistor 27 are arranged. Second connection point with
A detection element 21 as a contact combustion type gas sensor connected to the output terminal 17 and between the first input terminal 11 and the second input terminal 13.
Also, the sensing element 21 and the compensating element 23 having an approximate resistance value are connected in series, and the connection point between the sensing element 21 and the compensating element 23 is connected to the first output terminal 15 and the first input terminal.
The adjustment resistor 31 of 2 KΩ is inserted between the 11 and the second input terminal 13, and the intermediate sliding terminal of the adjustment resistor 31 is also connected to the first output terminal 15 to form a circuit. The potential of the first output terminal 15 is set to be slightly lower than the potential of the second output terminal 17 by adjusting the moving contact position. When gas is generated in the air, the resistance value of the detection element 21 becomes The gas detection circuit of the gas leak alarm device is configured to issue an alarm when the potential of the first output terminal 15 increases and the potential of the first output terminal 15 becomes equal to the potential of the second output terminal 17.
【0013】このように、本実施例では、調整抵抗器31
の中間摺動端子を第1出力端子15に接続している故、調
整抵抗器31の一部を検知素子21と並列に、又、調整抵抗
器31の一部を補償素子23と並列に接続することとなり、
調整抵抗器31の摺動接点位置を調節することにより第1
出力端子15の電位調整を容易に行うことが可能であると
共に、検知素子21や補償素子23と並列に抵抗器が挿入さ
れるため、検知素子21や補償素子23の抵抗値が周囲温度
により変化する場合、合成抵抗値の変化を小さくして出
力変動を少なくすることができる。Thus, in this embodiment, the adjustment resistor 31
Since the intermediate sliding terminal of is connected to the first output terminal 15, a part of the adjusting resistor 31 is connected in parallel with the sensing element 21 and a part of the adjusting resistor 31 is connected in parallel with the compensating element 23. Will be done,
By adjusting the sliding contact position of the adjusting resistor 31,
It is possible to easily adjust the potential of the output terminal 15, and since a resistor is inserted in parallel with the sensing element 21 and the compensating element 23, the resistance values of the sensing element 21 and the compensating element 23 change depending on the ambient temperature. In this case, the change in the combined resistance value can be reduced to reduce the output fluctuation.
【0014】又、調整抵抗器31の抵抗値を検知素子21や
補償素子23の抵抗値に対して数十倍としておけば、検知
素子21がガスに反応して検知素子21の抵抗値が変化した
ときには、第1出力端子15の電位が上昇する故、第1固
定抵抗器25と第2固定抵抗器27とで構成した固定抵抗器
の中点となる両抵抗器の接続点に接続された第2出力端
子17の電位と所定のガス濃度で等しくなるように第1出
力端子15の電位を第2出力端子17の電位よりも僅かに低
く設定しておくことにより、ガス濃度が所定の値に達し
たとき、第1出力端子15と第2出力端子17とを同電位と
することができるものである。If the resistance value of the adjusting resistor 31 is set to several tens of times the resistance value of the sensing element 21 and the compensating element 23, the sensing element 21 reacts with gas and the resistance value of the sensing element 21 changes. When this happens, the potential of the first output terminal 15 rises, so it was connected to the connection point of both resistors, which is the middle point of the fixed resistor composed of the first fixed resistor 25 and the second fixed resistor 27. By setting the electric potential of the first output terminal 15 slightly lower than the electric potential of the second output terminal 17 so that the electric potential of the second output terminal 17 becomes equal to the predetermined gas concentration, the gas concentration becomes a predetermined value. When it reaches, the first output terminal 15 and the second output terminal 17 can be set to the same potential.
【0015】即ち、このガス検知回路として、検知素子
21及び補償素子23に約40Ωの抵抗値を有する素子を用
い、適宜の検知素子21と補償素子23とを組み合わせた2
0組の比較的素子抵抗値の大きな素子の組合せによるサ
ンプルを形成し、この検知素子21及び補償素子23と並列
に調整抵抗器31を接続し、入力端子間に2.4Vの電圧
を印加して図2に示す表のように25℃の大気中で第1
出力端子15の電位を第2出力端子17の電位よりも約15
mV乃至17mV程度低くなるように調整抵抗器31を調
整し、その後、気温を−10℃として各サンプルによる
第1出力端子15と第2出力端子17との電位差を検出する
と、各サンプルは25℃のときに比較して1mV乃至3
mV程度の電位変動を生じ、気温を50℃として各サン
プルによる第1出力端子15と第2出力端子17との電位差
を検出すると、25℃のときと比較して1mV乃至2m
Vの電位変動を生じ、内には0.1mV乃至0.2mV
程度と僅んど周囲温度の影響を受けない組み合わせとな
るサンプルもあった。That is, as this gas detection circuit, a detection element
21 and the compensating element 23 are elements having a resistance value of about 40 Ω, and the sensing element 21 and the compensating element 23 are combined appropriately.
A sample is formed by combining 0 sets of elements having relatively large element resistance values, an adjusting resistor 31 is connected in parallel with the sensing element 21 and the compensating element 23, and a voltage of 2.4 V is applied between the input terminals. As shown in the table in Figure 2,
The potential of the output terminal 15 is about 15 more than the potential of the second output terminal 17.
The adjustment resistor 31 is adjusted so as to be lowered by about mV to 17 mV, and then, when the temperature difference is set to −10 ° C. and the potential difference between the first output terminal 15 and the second output terminal 17 by each sample is detected, each sample is 25 ° C. 1mV to 3 compared to
When the potential difference between the first output terminal 15 and the second output terminal 17 of each sample is detected when the temperature fluctuates at about 50 ° C. and the potential changes about 1 mV, it is 1 mV to 2 m compared with the case of 25 ° C.
V potential fluctuation occurs, and within 0.1 mV to 0.2 mV
In some samples, the combination was not affected by the degree and the ambient temperature.
【0016】そして、各サンプルによるこの検知回路を
25℃で一酸化炭素1000ppmの零囲気中に置く
と、第1出力端子15の電位は約17mV乃至19mV程
度上昇し、一酸化炭素の1000ppm未満の濃度で警
報を発し得るガス検知回路とすることができた。又、こ
の各サンプルとした検知素子21と補償素子23の組み合わ
せを用い、図7に示したように調整抵抗器31の摺動端子
を第2出力端子17に接続した従来のガス検知回路とし、
第1出力端子15と第2出力端子17との電位差である設定
電位差を約15mV乃至17mVとするように第1出力
端子15の電位に対して第2出力端子17の電位を僅かに高
く調整しておき、同様に−10℃や50℃の気温として
各サンプルにおける第1出力端子15と第2出力端子17の
電位差を測定したところ、図3に示すように、−10℃
では25℃のときに比較して第1出力端子15の電位は3
mV乃至10mV変化し、50℃では25℃のときに比
較して2mV乃至6mV程度の変化が生じた。When this detection circuit for each sample is placed in a zero atmosphere of carbon monoxide of 1000 ppm at 25 ° C., the potential of the first output terminal 15 rises by about 17 mV to 19 mV and is less than 1000 ppm of carbon monoxide. It could be a gas detection circuit capable of issuing an alarm depending on the concentration. Also, using the combination of the sensing element 21 and the compensating element 23 as each sample, a conventional gas sensing circuit in which the sliding terminal of the adjusting resistor 31 is connected to the second output terminal 17 as shown in FIG. 7,
Adjust the potential of the second output terminal 17 slightly higher than the potential of the first output terminal 15 so that the set potential difference between the first output terminal 15 and the second output terminal 17 is about 15 mV to 17 mV. Similarly, when the potential difference between the first output terminal 15 and the second output terminal 17 in each sample was similarly measured at an air temperature of −10 ° C. or 50 ° C., as shown in FIG.
Then, the potential of the first output terminal 15 is 3 compared to that at 25 ° C.
mV to 10 mV, and a change of about 2 mV to 6 mV occurred at 50 ° C. as compared with the case of 25 ° C.
【0017】なお、このときの25℃における一酸化炭
素濃度1000ppm零囲気とした場合の第1出力端子
15の電圧上昇は約18mV乃至19mV余りであった。
すなわち、約40Ωの抵抗値を有する検知素子21及び補
償素子23に、合計が2KΩとなるような数百Ω乃至数千
百Ωの抵抗器を各々検知素子21や補償素子23と並列に設
けて第1出力端子15の電位を入力電圧の2分の1よりも
僅かに低く設定すると、検知素子21や補償素子23と並列
に抵抗器を設けない場合に比較し、ガス検知感度は数%
程度低下するも、温度変化によるドリフトを30乃至4
0%程度に低下させることができた。At this time, the first output terminal when the carbon monoxide concentration at 25 ° C. is 1000 ppm and the atmosphere is zero
The voltage rise of 15 was about 18 mV to 19 mV.
That is, a sensing element 21 and a compensating element 23 having a resistance value of about 40Ω are provided in parallel with the sensing element 21 and the compensating element 23, respectively, with resistors of several hundred Ω to several hundreds of Ω so that the total is 2 KΩ. When the potential of the first output terminal 15 is set slightly lower than half of the input voltage, the gas detection sensitivity is several% as compared with the case where no resistor is provided in parallel with the detection element 21 or the compensation element 23.
Although it decreases to some extent, the drift due to temperature change is 30 to 4
It could be reduced to about 0%.
【0018】又、上記20組のサンプルの内、第1サン
プルから第10サンプルについて±10%の電圧変動試
験を行ったところ、図1に示した本発明の実施例では、
図4に示すように、印加電圧を2.16Vに低下させた
とき、第1出力端子15と第2出力端子17との電位差は1
2.5mV乃至14.5mVとなって2.4Vを入力端
子に印加した場合の電位差に対して2mV乃至3mV小
さくなり、2.64Vを入力端子に印加したときの第1
出力端子15と第2出力端子17との電位差は約17mV乃
至19mVとなって2mV乃至3mV程度電位差が大き
くなった。A voltage fluctuation test of ± 10% was performed on the first sample to the tenth sample of the above 20 sets of samples, and in the embodiment of the present invention shown in FIG.
As shown in FIG. 4, when the applied voltage is reduced to 2.16V, the potential difference between the first output terminal 15 and the second output terminal 17 is 1
It becomes 2.5 mV to 14.5 mV, which is smaller than the potential difference when 2.4 V is applied to the input terminal by 2 mV to 3 mV, and the first when 2.64 V is applied to the input terminal.
The potential difference between the output terminal 15 and the second output terminal 17 was about 17 mV to 19 mV, and the potential difference increased by about 2 mV to 3 mV.
【0019】他方、この10組のサンプルを用いて気温
25℃、印加電圧2.4Vとしつつ、第2出力端子17を
第1出力端子15よりも約15mV乃至17mV程度高く
するように調整した前記従来回路では、図5に示すよう
に、印加電圧が2.16Vに低下すると第1出力端子15
と第2出力端子17の電位差は約10mV乃至13.5m
Vとなり、約2.5mV乃至6mVの電位差変動が生
じ、又、印加電圧を2.64Vとすると電位差は約17
mV乃至21mVと大きくなり、電位差変動が約2.5
mVから6mV近くなった。On the other hand, the temperature of the temperature of 25 ° C. and the applied voltage of 2.4 V are adjusted by using these 10 sets of samples, and the second output terminal 17 is adjusted to be higher than the first output terminal 15 by about 15 mV to 17 mV. In the conventional circuit, as shown in FIG. 5, when the applied voltage drops to 2.16V, the first output terminal 15
And the potential difference between the second output terminal 17 is about 10 mV to 13.5 m
V, a potential difference fluctuation of about 2.5 mV to 6 mV occurs, and when the applied voltage is 2.64 V, the potential difference is about 17
It becomes as large as mV to 21 mV, and the potential difference fluctuation is about 2.5.
It became close to 6 mV from mV.
【0020】すなわち、本発明の実施例では電源電圧の
変動による電位差の変化も60%に低減することがで
き、検知素子21や補償素子23と並列に挿入する調整抵抗
器31の抵抗値を検知素子21や補償素子23の抵抗値の数十
倍以上としておけば、ガス検知感度を余り低下させるこ
となく温度変化によるドリフトや電源電圧の変動による
出力変動を大幅に減少させることができたものである。That is, in the embodiment of the present invention, the change in the potential difference due to the change in the power supply voltage can be reduced to 60%, and the resistance value of the adjusting resistor 31 inserted in parallel with the detecting element 21 and the compensating element 23 is detected. By setting the resistance value of the element 21 and the compensating element 23 to several tens of times or more, it is possible to significantly reduce the drift due to the temperature change and the output fluctuation due to the fluctuation of the power supply voltage without significantly lowering the gas detection sensitivity. is there.
【0021】このように、本実施例は、調整抵抗器31を
検知素子21及び補償素子23と並列に設けて検知素子21と
補償素子23との接続点の電位を調整可能とし、検知素子
21や補償素子23と並列に抵抗値の等しい2個の固定抵抗
器を直列に設けたブリッジ回路としている故、温度変化
によるドリフトを少なくし、且つ、電圧変動による出力
電位差の変動をも小さくすることができ、従って設定電
位差を小さくするように調整設定しておくことにより低
いガス濃度でも誤動作を生じさせることなく正しい警報
を出させることができる検出器のガス検知回路とするこ
とができるものである。As described above, in this embodiment, the adjusting resistor 31 is provided in parallel with the sensing element 21 and the compensating element 23 so that the potential at the connection point between the sensing element 21 and the compensating element 23 can be adjusted, and the sensing element
Since it is a bridge circuit in which two fixed resistors having the same resistance value are provided in series in parallel with 21 and the compensating element 23, the drift due to the temperature change is reduced and the change in the output potential difference due to the voltage change is also reduced. Therefore, it is possible to provide a gas detection circuit of a detector that can give a correct alarm without causing a malfunction even at a low gas concentration by adjusting and setting the set potential difference to be small. is there.
【0022】尚、調整抵抗器31と検知素子21や補償素子
23との接続は、例えば補償素子23と並列に1KΩ乃至2
KΩ程度の固定抵抗値を有する固定抵抗器を設け、検知
素子21と並列に調整抵抗器としての可変抵抗器を接続す
ることもできる。The adjusting resistor 31, the sensing element 21 and the compensating element
The connection with 23 is, for example, 1 KΩ to 2 in parallel with the compensating element 23.
It is also possible to provide a fixed resistor having a fixed resistance value of about KΩ and connect a variable resistor as an adjusting resistor in parallel with the sensing element 21.
【0023】[0023]
【発明の効果】本発明は、検知素子及び補償素子に各々
並列に調整抵抗を挿入する接触燃焼式ガスセンサのガス
検出回路である故、調整抵抗器の抵抗値を調節して直列
に設けた2個の固定抵抗器の中間電位に対して検知素子
による電位を調整設定することができ、検知素子や補償
素子と並列に調整抵抗が配置されている故、検知素子や
補償素子の抵抗値が気温等により変化する場合であって
も、このドリフトを小さくして正確なガス検知を行うこ
とができるガス検出回路であり、検知素子と補償素子と
の特性が多少異なっていても正確なガス検出を行うこと
ができるものである。The present invention is a gas detection circuit of a catalytic combustion type gas sensor in which adjusting resistors are inserted in parallel with the sensing element and the compensating element, respectively. Therefore, the resistance value of the adjusting resistor is adjusted to be provided in series. The potential of the sensing element can be adjusted and set with respect to the intermediate potential of each fixed resistor, and the adjusting resistor is arranged in parallel with the sensing element and the compensating element. It is a gas detection circuit that can perform accurate gas detection by reducing this drift even when it changes due to factors such as, etc. Even if the characteristics of the detection element and the compensation element are slightly different, accurate gas detection is possible. Is what you can do.
【0024】尚、検知素子や補償素子と並列に接続する
調整抵抗器として単一の抵抗器を用いつつ、中間摺動端
子を検知素子と補償素子との接続点と接続するガス検出
回路は、回路構成を単純としつつ出力調整を容易に行う
ことができるものである。It should be noted that the gas detection circuit for connecting the intermediate sliding terminal to the connection point between the detection element and the compensation element while using a single resistor as the adjustment resistor connected in parallel with the detection element and the compensation element, The output can be easily adjusted while simplifying the circuit configuration.
【図1】本発明に係るガス検知回路の回路例を示す図。FIG. 1 is a diagram showing a circuit example of a gas detection circuit according to the present invention.
【図2】本発明に係るガス検知回路の回路例における温
度変化特性を示す表図。FIG. 2 is a table showing temperature change characteristics in a circuit example of a gas detection circuit according to the present invention.
【図3】従来のガス検知回路における温度変化特性を示
す表図。FIG. 3 is a table showing temperature change characteristics in a conventional gas detection circuit.
【図4】本発明に係るガス検知回路の回路例における電
圧変化特性を示す表図。FIG. 4 is a table showing voltage change characteristics in a circuit example of a gas detection circuit according to the present invention.
【図5】従来のガス検知回路における電圧変化特性を示
す表図。FIG. 5 is a table showing voltage change characteristics in a conventional gas detection circuit.
【図6】従来のガス検知回路の一例を示す回路図。FIG. 6 is a circuit diagram showing an example of a conventional gas detection circuit.
【図7】従来のガス検知回路の他の例を示す回路図。FIG. 7 is a circuit diagram showing another example of a conventional gas detection circuit.
11 第1入力端子 13 第2入力端子
15 第1出力端子 17 第2出力端子
21 検知素子 23 補償素子
25 第1固定抵抗器 27 第2固定抵抗
器
31,33,35 調整抵抗器11 First Input Terminal 13 Second Input Terminal 15 First Output Terminal 17 Second Output Terminal 21 Sensing Element 23 Compensating Element 25 First Fixed Resistor 27 Second Fixed Resistor 31, 33, 35 Adjusting Resistor
Claims (2)
償素子に各々並列に調整抵抗器を接続して前記検知素子
と補償素子とを直列とし、この検知素子及び補償素子と
並列に固定抵抗器を有し、固定抵抗器の中点及び検知素
子と補償素子との接続点を各々出力端子とすることを特
徴とする接触燃焼式ガスセンサを用いたガス検知回路。1. A sensing resistor and a compensating element of a catalytic combustion type gas sensor are connected in parallel with adjusting resistors respectively to connect the sensing element and the compensating element in series, and a fixed resistor is provided in parallel with the sensing element and the compensating element. A gas detection circuit using a catalytic combustion type gas sensor, characterized in that a middle point of a fixed resistor and a connection point between a detection element and a compensation element are used as output terminals.
端及び補償素子の一端に接続して調整抵抗器を検知素子
及び補償素子と並列に設け、調整抵抗器の中間摺動端子
を検出素子と補償素子との接続点に接続したことを特徴
とする請求項1に記載の接触燃焼式ガスセンサを用いた
ガス検知回路。2. An adjusting resistor is provided in parallel with the detecting element and the compensating element by connecting both ends of one adjusting resistor to one end of the detecting element and one end of the compensating element, and an intermediate sliding terminal of the adjusting resistor is provided. The gas detection circuit using the catalytic combustion gas sensor according to claim 1, wherein the gas detection circuit is connected to a connection point between the detection element and the compensation element.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP09460094A JP3523323B2 (en) | 1994-05-09 | 1994-05-09 | Gas detection circuit using contact combustion type gas sensor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP09460094A JP3523323B2 (en) | 1994-05-09 | 1994-05-09 | Gas detection circuit using contact combustion type gas sensor |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH07301612A JPH07301612A (en) | 1995-11-14 |
JP3523323B2 true JP3523323B2 (en) | 2004-04-26 |
Family
ID=14114759
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JP09460094A Expired - Fee Related JP3523323B2 (en) | 1994-05-09 | 1994-05-09 | Gas detection circuit using contact combustion type gas sensor |
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JP (1) | JP3523323B2 (en) |
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JP5385055B2 (en) * | 2009-08-31 | 2014-01-08 | 矢崎総業株式会社 | Gas detector |
JP5356957B2 (en) * | 2009-09-10 | 2013-12-04 | 矢崎総業株式会社 | Gas detector |
JP5468164B2 (en) * | 2013-07-04 | 2014-04-09 | 矢崎エナジーシステム株式会社 | Gas alarm |
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- 1994-05-09 JP JP09460094A patent/JP3523323B2/en not_active Expired - Fee Related
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