JPH0259949B2 - - Google Patents
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- Publication number
- JPH0259949B2 JPH0259949B2 JP58074970A JP7497083A JPH0259949B2 JP H0259949 B2 JPH0259949 B2 JP H0259949B2 JP 58074970 A JP58074970 A JP 58074970A JP 7497083 A JP7497083 A JP 7497083A JP H0259949 B2 JPH0259949 B2 JP H0259949B2
- Authority
- JP
- Japan
- Prior art keywords
- compensation
- detection
- bridge
- change
- hot wire
- 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.)
- Expired - Lifetime
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/14—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature
- G01N27/16—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【発明の詳細な説明】
この発明は、接触燃焼式可燃性ガス検出装置に
使用されるブリツジに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bridge used in a catalytic combustion type combustible gas detection device.
従来、可燃性ガス検出用ブリツジとしては、ガ
ス検出素子および補償素子が直列に接続された第
１の直列２辺の両端と２つの抵抗素子が直列に接
続された第２の直列２辺の両端とを接続し、該両
接続点を入力端子とするとともに前記第１、第２
の直列２辺の中間接続点を出力端子とするものが
知られており、このもののガス検出素子は、白金
等からなる検出熱線と、検出熱線の周囲に付着さ
れた白色のアルミナ等からなる検出担体と、検出
担体に担持され黒褐色のパラジウム等からなり可
燃性ガスを燃焼させる酸化触媒と、から構成さ
れ、一方、補償素子は、白金等からなる補償熱線
と、補償熱線の周囲に付着された白色のアルミナ
等からなる補償担体と、から構成されている。そ
して、このようなブリツジを用いて可燃性ガスの
存否あるいは濃度を検出する場合には、入力端子
から両直列２辺に通電してガス検出素子および補
償素子を検出温度まで加熱した後前記抵抗素子の
抵抗値を変化させて出力端子から零を含む所定の
出力電圧（零点出力）が出力するようにする。こ
のときにおけるガス検出素子および補償素子自身
の温度は、各素子からの放熱量と検出、補償熱線
の発熱量とがバランスしたときの温度となり、前
記放熱量は各素子自身の温度と周囲の温度との差
により決定され、一方、発熱量は各熱線の抵抗
値、すなわち各素子自身の温度、により決定され
る。したがつて、例えば電源電池の経時変化等に
よつて入力電圧が変動したり、あるいは周囲の温
度が変動すると、両素子の発熱量、放熱量がそれ
ぞれ変化して両素子の温度が変わる。しかしなが
ら、この場合、ガス検出素子のみが担体と全く色
の異なる酸化触媒を担持しているため、両素子の
放射熱量が異なり、この結果、両素子の温度の変
化率が大きく異なつてしまう。このため、ブリツ
ジのバランスが崩れて最初の出力電圧とは異なつ
た値の出力電圧が出力され、零点が大きく変動
し、大きな誤差が発生するという問題点がある。
このような問題点を解決するために、入力電圧の
変動に対しては定電圧回路を設け、一方、周囲温
度の変動に対しては例えばサーミスタ等を用いて
温度補償することも考えられるが、このようにす
ると、検出装置全体が複雑かつ高価になるという
問題点がある。 Conventionally, a bridge for combustible gas detection has two sides: one at both ends of two first series sides in which a gas detection element and a compensation element are connected in series, and the other at both ends of two series sides in which two resistance elements are connected in series. are connected, and both connection points are used as input terminals, and the first and second
It is known that the output terminal is the intermediate connection point of two sides in series, and the gas detection element of this device consists of a detection hot wire made of platinum, etc., and a detection hot wire made of white alumina, etc. attached around the detection hot wire. It is composed of a carrier and an oxidation catalyst supported on the detection carrier and made of blackish brown palladium or the like and burns a combustible gas.On the other hand, the compensation element is composed of a compensation heating wire made of platinum or the like and a compensation heating wire attached around the compensation heating wire. and a compensation carrier made of white alumina or the like. When detecting the presence or absence or concentration of combustible gas using such a bridge, electricity is applied from the input terminal to both sides in series to heat the gas detection element and the compensation element to the detection temperature, and then the resistance element is heated. By changing the resistance value of the output terminal, a predetermined output voltage including zero (zero point output) is outputted from the output terminal. At this time, the temperature of the gas detection element and the compensation element itself is the temperature when the amount of heat dissipated from each element and the amount of heat generated by the detection and compensation heating wire are balanced, and the amount of heat dissipated is the temperature of each element itself and the ambient temperature. On the other hand, the amount of heat generated is determined by the resistance value of each heating wire, that is, the temperature of each element itself. Therefore, when the input voltage fluctuates due to aging of the power supply battery, for example, or when the ambient temperature fluctuates, the amount of heat generated and the amount of heat dissipated from both elements change, and the temperature of both elements changes. However, in this case, since only the gas detection element carries an oxidation catalyst that is completely different in color from the carrier, the amount of radiated heat of both elements is different, and as a result, the rate of change in temperature of both elements is greatly different. As a result, the balance of the bridge is disrupted, and an output voltage having a value different from the initial output voltage is output, causing a problem in that the zero point fluctuates greatly and a large error occurs.
In order to solve these problems, it may be possible to provide a constant voltage circuit to handle fluctuations in input voltage, while compensating for fluctuations in ambient temperature using, for example, a thermistor. If this is done, there is a problem that the entire detection device becomes complicated and expensive.
この発明は、入力電圧や周囲温度に変動があつ
てもバランスの崩れにくい簡単でかつ安価なブリ
ツジを提供することを目的としている。 The object of the present invention is to provide a simple and inexpensive bridge that does not lose its balance even when the input voltage or ambient temperature fluctuates.
目的は、補償担体に担持された金属酸化物から
なる補償体の色を酸化触媒の色に近似させ、これ
によつて、可燃性ガス検出用ブリツジの入力電圧
の変化に対する補償熱線の抵抗値の変化を前記入
力電圧の変化に対する検出熱線の抵抗値の変化に
近似させることにより達成することができる。 The purpose is to approximate the color of the compensator made of a metal oxide supported on the compensation carrier to the color of the oxidation catalyst, thereby making it possible to control the resistance value of the compensation hot wire against changes in the input voltage of the combustible gas detection bridge. This can be achieved by approximating the change in the resistance value of the detection hot wire with respect to the change in the input voltage.
以下、この発明の一実施例の構成を図面に基づ
いて説明する。 Hereinafter, the configuration of an embodiment of the present invention will be described based on the drawings.
第１図において、１は接触燃焼式可燃性ガス検
出装置であり、この検出装置１はブリツジ２を有
する。このブリツジ２は、第１のリード線３と、
第１のリード線３の途中に直列に接続された補償
素子４およびガス検出素子５と、からなる第１の
直列２辺６を有する。前記検出素子４およびガス
検出素子５は、それぞれ第１のリード線３に接続
されたコイル状の補償熱線７および検出熱線８を
有し、これらの補償、検出熱線７，８は例えば白
金の細線から構成されている。補償熱線７および
検出熱線８の周囲には補償担体９および検出担体
１０がそれぞれ付着され、これらの補償、検出担
体９，１０はほぼ白色をしたアルミナ（Al2O3）、
シリカ（SiO2）、アルミナ−シリカ混合物、ガラ
ス等の耐火物から構成されている。前記検出担体
１０には、塗布、焼成を繰り返すことにより酸化
触媒１１が担持され、この酸化触媒１１はガス検
出素子５が検出温度まで加熱されたとき、可燃性
ガス、例えばイソブタンガス、メタンガス、塩化
メチルガスの燃焼を促進する。この酸化触媒１１
は、以下に示すようなものを主成分としている。
例えば、パラジウム（黒褐色）、ロジウム（褐
色）、白金（黒色）、酸化ロジウム（暗灰色）、酸
化パラジウム（黒色）、酸化イリジウム（黒色）、
酸化白金（暗灰色）、二酸化白金（黒色）、三酸化
白金（茶褐色）または前記材質から選ばれた２種
以上の混合物若しくは合金からなる。前述した検
出熱線８、検出担体１０および酸化触媒１１は全
体としてガス検出素子５を構成する。一方、補償
担体９には可燃性ガスに対して不活性の補償体１
２が担持され、この補償体１２は前記酸化触媒１
１とほぼ等厚で補償担体９の周囲を被覆してい
る。この補償体１２は前記酸化触媒１１と同様に
金属酸化物からなり、例えば、酸化クロム（暗褐
色）、四三酸化鉄（黒褐色）、酸化金（黒色）、酸
化マンガン（褐色）、酸化ニツケル（黒色）、酸化
第１銅（黒色）、酸化第２銅（暗赤褐色）、酸化モ
リブデン（黒色）、酸化鉛（赤色）または前記金
属酸化物から選ばれた２種以上の混合物からな
る。ここで、この補償体１２は、ガス検出素子５
の放射熱量の変化率に補償素子４の放射熱量の変
化率を近付けるために、酸化触媒１１の色に近似
した色の金属酸化物を使用する。特に、パラジウ
ム、ロジウム、またはこれらの混合物（茶褐色）
又は合金（茶褐色）に対しては酸化クロム（暗褐
色）、四三酸化鉄（黒褐色）が、白金又は白金−
パラジウムの混合物（黒色）又は合金（黒色）に
対しては酸化金（黒色）が好ましい。このような
補償体１２を補償担体９に担持させるには、例え
ば補償体１２が酸化クロム、四三酸化鉄、酸化金
の場合には、それぞれ塩化クロム酸水溶液、アン
モニア＋硝酸第２鉄混合液、塩化金酸水溶液を補
償担体９に塗布し焼成する工程を繰り返すことに
より行なう。前述した補償熱線７、補償担体９お
よび補償体１２は全体として補償素子４を構成す
る。この発明においては、前述のように補償素子
４の補償担体９にも、金属酸化物（補償担体９の
色よりは酸化触媒１１の色に近似している）から
なる補償体１２を担持させたので、ブリツジ２の
入力電圧の変化に対する補償熱線７の抵抗値の変
化がブリツジ２の入力電圧の変化に対する検出熱
線８の抵抗値の変化に近似してくる。そして、こ
のような金属酸化物の選定作業は、色についての
検討を行なうだけでよいので、容易に行なうこと
ができる。１３は第２のリード線であり、この第
２のリード線１３の両端は前記第１のリード線３
の両端にそれぞれ接続されている。そして、これ
らの両接続点がブリツジ２の電源入力端子１４，
１５となる。第２のリード線１３の途中には固定
抵抗素子１６および可変抵抗素子１７が直列に接
続されている。前述した第２のリード線１３およ
び２個の抵抗素子１６，１７は全体として第２の
直列２辺１８を構成する。前記第１、第２の直列
２辺６，１８の中間接続点はそれぞれ出力端子１
９，２０となり、これらの出力端子１９，２０に
はリード線２１を介してアナログ表示器、例えば
電圧計２２、が接続されている。一方、前記入力
端子１４，１５にはリード線２３を介して直流電
源、例えば電池２４、が接続されている。 In FIG. 1, reference numeral 1 denotes a catalytic combustion type combustible gas detection device, and this detection device 1 has a bridge 2. As shown in FIG. This bridge 2 has a first lead wire 3,
It has two first series sides 6 consisting of a compensation element 4 and a gas detection element 5 connected in series in the middle of the first lead wire 3. The detection element 4 and the gas detection element 5 each have a coil-shaped compensation hot wire 7 and a detection hot wire 8 connected to the first lead wire 3, and these compensation and detection hot wires 7 and 8 are made of thin platinum wires, for example. It consists of A compensation carrier 9 and a detection carrier 10 are attached around the compensation heating wire 7 and the detection heating wire 8, respectively, and these compensation and detection carriers 9 and 10 are made of almost white alumina (Al 2 O 3 ),
It is composed of refractories such as silica (SiO 2 ), alumina-silica mixture, and glass. An oxidation catalyst 11 is supported on the detection carrier 10 by repeating coating and firing, and when the gas detection element 5 is heated to the detection temperature, the oxidation catalyst 11 releases a combustible gas such as isobutane gas, methane gas, chloride gas, etc. Promotes combustion of methyl gas. This oxidation catalyst 11
The main components are as shown below.
For example, palladium (blackish brown), rhodium (brown), platinum (black), rhodium oxide (dark gray), palladium oxide (black), iridium oxide (black),
It is made of platinum oxide (dark gray), platinum dioxide (black), platinum trioxide (brown), or a mixture or alloy of two or more selected from the above materials. The aforementioned detection hot wire 8, detection carrier 10, and oxidation catalyst 11 constitute the gas detection element 5 as a whole. On the other hand, the compensating carrier 9 has a compensating body 1 that is inert to combustible gas.
2 is supported, and this compensator 12 supports the oxidation catalyst 1
The periphery of the compensation carrier 9 is coated with approximately the same thickness as 1. This compensator 12 is made of a metal oxide like the oxidation catalyst 11, and includes, for example, chromium oxide (dark brown), triiron tetroxide (black brown), gold oxide (black), manganese oxide (brown), nickel oxide ( (black), cuprous oxide (black), cupric oxide (dark reddish brown), molybdenum oxide (black), lead oxide (red), or a mixture of two or more selected from the above metal oxides. Here, this compensator 12 is connected to the gas detection element 5
In order to bring the rate of change in the amount of radiant heat of the compensation element 4 close to the rate of change in the amount of radiant heat of the compensating element 4, a metal oxide having a color similar to that of the oxidation catalyst 11 is used. In particular, palladium, rhodium or mixtures thereof (brown)
Or for alloys (brown), chromium oxide (dark brown), triiron tetroxide (black brown), platinum or platinum-
Gold oxide (black) is preferred for palladium mixtures (black) or alloys (black). In order to support such a compensator 12 on the compensation carrier 9, for example, when the compensator 12 is chromium oxide, triiron tetroxide, or gold oxide, an aqueous chromic acid chloride solution or a mixed solution of ammonia and ferric nitrate are used, respectively. This is carried out by repeating the steps of applying a chloroauric acid aqueous solution to the compensation carrier 9 and baking it. The above-mentioned compensation hot wire 7, compensation carrier 9 and compensation body 12 constitute the compensation element 4 as a whole. In this invention, as described above, the compensation carrier 9 of the compensation element 4 also carries the compensator 12 made of a metal oxide (the color is closer to the oxidation catalyst 11 than the color of the compensation carrier 9). Therefore, a change in the resistance value of the compensation hot wire 7 with respect to a change in the input voltage of the bridge 2 approximates a change in the resistance value of the detection hot wire 8 with respect to a change in the input voltage of the bridge 2. The selection of such a metal oxide can be easily carried out since it is only necessary to consider the color. 13 is a second lead wire, and both ends of this second lead wire 13 are connected to the first lead wire 3.
are connected to both ends of the Then, these two connection points are connected to the power input terminal 14 of the bridge 2,
It becomes 15. A fixed resistance element 16 and a variable resistance element 17 are connected in series in the middle of the second lead wire 13. The aforementioned second lead wire 13 and the two resistance elements 16 and 17 collectively constitute two second series sides 18 . The intermediate connection points of the first and second series sides 6 and 18 are output terminals 1 and 18, respectively.
9 and 20, and an analog display, such as a voltmeter 22, is connected to these output terminals 19 and 20 via a lead wire 21. On the other hand, a DC power source, such as a battery 24, is connected to the input terminals 14 and 15 via lead wires 23.
以下、この発明の一実施例の作用について説明
する。 Hereinafter, the operation of one embodiment of the present invention will be explained.
まず、電池２４から第１および第２の直列２辺
６，１８に通電されると、ガス検出素子５および
補償素子４はそれぞれ所定の検出温度まで加熱さ
れる。このときの各素子５，４の温度はその放熱
量と各熱線８，７の発熱量とにより決定される。
この結果、出力端子１９，２０から出力電圧が電
圧計２２に出力される。次に、可変抵抗素子１７
の抵抗値を変化させて出力電圧を零点出力にしブ
リツジ２をバランスさせる。次に、可燃性ガスを
ガス検出素子５および補償素子４に接触させる。
これにより、可燃性ガスは酸化触媒１１に接触し
て燃焼し、その燃焼熱をガス検出素子５に与え
る。この結果、ガス検出素子５の温度が上昇し、
検出熱線８の抵抗値が増大する。一方、補償素子
４には不活性の補償体１２が担持されているの
で、可燃性ガスは燃焼せず、この結果、補償素子
４は前記検出温度を維持する。これにより、ブリ
ツジ２のバランスが崩れ、出力端子１９，２０か
らの出力電圧が増大して電圧計２２の針が振れ
る。このときの出力電圧の増大量は可燃性ガスの
濃度に対応しているので、前記電圧計２２の針の
振れ量を見ることによりガス濃度を知ることがで
きる。このような検出中に、例えば電池２４の経
時変化によつて、入力電圧が変動すると、両素子
４，５の温度はそれぞれ変化し、放熱量と発熱量
とがバランスした温度にそれぞれ落ち付く。この
ときの各素子４，５の温度と各熱線７，８の抵抗
値とは対応関係がある。ここで、前述のように、
ブリツジ２の入力電圧の変化に対する補償熱線７
の抵抗値の変化がブリツジ２の入力電圧の変化に
対する検出熱線８の抵抗値の変化に近似している
ので、両素子４，５の熱線７，８の抵抗値の変化
率はほぼ等しくなり、この結果、入力電圧の変動
に対するブリツジ２のバランスの崩れが小さくな
つて安定性が向上する。一方、検出中に周囲温度
が変化すると、両素子４，５の温度がそれぞれ変
化するが、両素子４，５は電圧変動に対してと同
様にこの周囲温度変化に対しても機能し、この結
果、両素子４，５自身の温度変化率（各熱線７，
８の抵抗変化率）はほぼ等しくなつて安定性が向
上する。このようにブリツジ２の安定性が向上す
るので、都市ガス、液化石油ガス向家庭用ガス警
報装置のブリツジとして好適である。 First, when electricity is applied from the battery 24 to the first and second series sides 6 and 18, the gas detection element 5 and the compensation element 4 are heated to respective predetermined detection temperatures. The temperature of each element 5, 4 at this time is determined by its heat radiation amount and the amount of heat generated by each heating wire 8, 7.
As a result, output voltage is output from the output terminals 19 and 20 to the voltmeter 22. Next, variable resistance element 17
By changing the resistance value of the bridge 2, the output voltage is set to zero point output and the bridge 2 is balanced. Next, combustible gas is brought into contact with the gas detection element 5 and the compensation element 4.
Thereby, the combustible gas comes into contact with the oxidation catalyst 11 and burns, giving the combustion heat to the gas detection element 5. As a result, the temperature of the gas detection element 5 rises,
The resistance value of the detection hot wire 8 increases. On the other hand, since the compensating element 4 carries the inert compensating body 12, the combustible gas does not burn, and as a result, the compensating element 4 maintains the detected temperature. As a result, the bridge 2 becomes unbalanced, the output voltage from the output terminals 19 and 20 increases, and the needle of the voltmeter 22 swings. Since the amount of increase in the output voltage at this time corresponds to the concentration of the combustible gas, the gas concentration can be determined by observing the amount of deflection of the needle of the voltmeter 22. During such detection, if the input voltage fluctuates due to aging of the battery 24, for example, the temperatures of both elements 4 and 5 change, and each settles to a temperature where the amount of heat dissipated and the amount of heat generated are balanced. At this time, there is a correspondence between the temperature of each element 4, 5 and the resistance value of each hot wire 7, 8. Here, as mentioned above,
Compensation hot wire 7 for changes in input voltage of bridge 2
Since the change in the resistance value of is similar to the change in the resistance value of the detection hot wire 8 with respect to the change in the input voltage of the bridge 2, the rate of change in the resistance value of the hot wires 7 and 8 of both elements 4 and 5 is approximately equal, As a result, the loss of balance of the bridge 2 due to fluctuations in input voltage is reduced, and stability is improved. On the other hand, if the ambient temperature changes during detection, the temperatures of both elements 4 and 5 will change, but both elements 4 and 5 will function against this ambient temperature change in the same way as against voltage fluctuations. As a result, the temperature change rate of both elements 4 and 5 themselves (each heating wire 7,
8) are almost equal, improving stability. Since the stability of the bridge 2 is improved in this way, it is suitable as a bridge for a household gas alarm system for city gas and liquefied petroleum gas.
次に、実験比較例を説明する。 Next, an experimental comparative example will be explained.
この実験においては、従来のブリツジとして以
下のようなものを使用した。まず、ガス検出素子
および補償素子の熱線には共に白金コイル線を使
用し、担体には共にアルミナを使用した。また、
酸化触媒としては、パラジウムと白金の混合物を
使用し、その割合は、検出担体と酸化触媒との合
計重量を100重量％としたとき、金属パラジウム
が５重量％、金属白金が３重量％、アルミナが残
部である。一方、この発明のブリツジは、前記従
来のブリツジの補償素子に補償体を担持させた他
は従来のブリツジと同一である。この補償体とし
ては酸化金を使用し、その割合は補償担体と補償
体との合計重量を100重量％としたとき、金属金
が２重量％、アルミナが残部である。このような
従来のブリツジおよびこの発明のブリツジに定格
の入力電圧（2.40V）を印加して所定の検出温度
まで加熱した後零点調節を行なつて出力電圧を零
（mV）とした。次に、入力電圧を定格電圧の±
10％変化させて各ブリツジの出力電圧を測定し
た。このときの測定結果が第２図に線Ａ，Ｂで示
されており、線Ａは従来のブリツジの測定結果で
あり、線Ｂはこの発明のブリツジの測定結果であ
る。この測定結果から、可燃性ガスの非検出時に
おいて電圧変動に対する安定性が向上しているこ
とが理解できる。次に、濃度3000ppmのメタンガ
スを従来と本発明の両ブリツジのガス検出素子、
補償素子に接触させた。ここで、前記濃度におけ
る両ブリツジの出力変化値（非検出時における出
力値からの上昇分）には殆んど差がなく、かつ、
電圧変動に対して線Ｃで示すように変動がないの
で、実際の電圧計で測定される結果は、従来のブ
リツジにあつては線Ａと線Ｃとの合成により求め
られる線Ｄとなり、この発明のブリツジにあつて
は線Ｂと線Ｃとの合成により求められる線Ｅとな
る。前述のように非検出時における安定性が良好
であるので、ガス検出時においても安定性は良好
である。 In this experiment, the following conventional bridge was used. First, platinum coiled wire was used for both the gas detection element and the compensation element, and alumina was used for the carrier. Also,
As the oxidation catalyst, a mixture of palladium and platinum is used, and the proportions are 5% by weight of metallic palladium, 3% by weight of metallic platinum, and 3% by weight of alumina, when the total weight of the detection carrier and oxidation catalyst is 100% by weight. is the remainder. On the other hand, the bridge of the present invention is the same as the conventional bridge except that the compensating element of the conventional bridge carries a compensator. Gold oxide is used as the compensator, and the ratio is 2% by weight of metallic gold and the balance of alumina, when the total weight of the compensation carrier and the compensator is 100% by weight. After applying a rated input voltage (2.40 V) to such conventional bridges and the bridge of the present invention and heating them to a predetermined detection temperature, zero point adjustment was performed to set the output voltage to zero (mV). Next, change the input voltage to ± of the rated voltage.
The output voltage of each bridge was measured with a 10% change. The measurement results at this time are shown by lines A and B in FIG. 2, where line A is the measurement result of the conventional bridge, and line B is the measurement result of the bridge of the present invention. From this measurement result, it can be understood that stability against voltage fluctuations is improved when no combustible gas is detected. Next, methane gas with a concentration of 3000 ppm was applied to the gas detection elements of both the conventional bridge and the present invention.
was brought into contact with the compensation element. Here, there is almost no difference in the output change value (increase from the output value at the time of non-detection) of both bridges at the concentration, and
Since there is no change in voltage as shown by line C, the result measured by an actual voltmeter is line D, which is obtained by combining line A and line C in the case of a conventional bridge. In the case of the bridge of the invention, line E is obtained by combining line B and line C. As described above, since the stability is good during non-detection, the stability is also good when gas is detected.
第３図は周囲温度を変化させた場合の実験比較
結果を示している。この実験に使用したブリツジ
は前述と同一のものであり、入力電圧およびガス
濃度も同一である。この実験においては周囲温度
が15℃のときに零点調節を行なつた後、周囲温度
を−10℃から＋40℃まで変化させて各ブリツジの
出力電圧を測定した。第３図中、線Ｆは従来のブ
リツジの測定結果を、線Ｇはこの発明のブリツジ
の測定結果を示している。この測定結果から、可
燃性ガスの非検出時において周囲温度の変化に対
する安定性が向上していることが理解できる。次
に、メタンガスを両ブリツジのガス検出素子、補
償素子に接触させた。ここで、前記濃度における
両ブリツジの出力変化値（非検出時における出力
値からの上昇分）には殆んど差がなく、かつ、周
囲温度変化に対して線Ｈで示すように変動がない
ので、実際の電圧計で測定される結果は、従来の
ブリツジにあつては線Ｆと線Ｈとの合成により求
められる線Ｉとなり、この発明のブリツジにあつ
ては線Ｇと線Ｈとの合成により求められる線Ｊと
なる。前述のように非検出時における安定性が良
好であるので、ガス検出時においても安定性は良
好である。 FIG. 3 shows the experimental comparison results when the ambient temperature was changed. The bridge used in this experiment was the same as previously described, with the same input voltage and gas concentration. In this experiment, after zero point adjustment was performed when the ambient temperature was 15°C, the output voltage of each bridge was measured while changing the ambient temperature from -10°C to +40°C. In FIG. 3, line F shows the measurement results of the conventional bridge, and line G shows the measurement results of the bridge of the present invention. From this measurement result, it can be understood that stability against changes in ambient temperature is improved when no flammable gas is detected. Next, methane gas was brought into contact with the gas detection elements and compensation elements of both bridges. Here, there is almost no difference in the output change value (increase from the output value when non-detection) of both bridges at the above concentration, and there is no fluctuation as shown by line H with respect to changes in ambient temperature. Therefore, in the case of the conventional bridge, the result measured by an actual voltmeter is line I obtained by combining line F and line H, and in the case of the bridge of the present invention, it is obtained by combining line G and line H. A line J is obtained by the synthesis. As described above, since the stability is good during non-detection, the stability is also good when gas is detected.
以上説明したように、この発明によれば、入力
電圧や周囲温度の変動に対する安定性が向上する
とともに、簡単でかつ安価に製作することができ
る。 As described above, according to the present invention, stability against fluctuations in input voltage and ambient temperature is improved, and manufacturing is simple and inexpensive.
第１図はこの発明を接触燃焼式可燃性ガス検出
装置に適用した一実施例を示す回路図、第２図は
入力電圧を変動させた実験の結果を示すグラフ、
第３図は周囲温度を変動させた実験の結果を示す
グラフである。
２……ブリツジ、４……補償素子、５……検出
素子、６……第１の直列２辺、７……補償熱線、
８……検出熱線、９……補償担体、１０……検出
担体、１１……酸化触媒、１２……補償体、１
４，１５……入力端子、１６，１７……抵抗素
子、１８……第２の直列２辺、１９，２０……出
力端子。
FIG. 1 is a circuit diagram showing an embodiment of the present invention applied to a catalytic combustion type combustible gas detection device, and FIG. 2 is a graph showing the results of an experiment in which the input voltage was varied.
FIG. 3 is a graph showing the results of experiments in which the ambient temperature was varied. 2... Bridge, 4... Compensation element, 5... Detection element, 6... First two series sides, 7... Compensation hot wire,
8...Detection heat ray, 9...Compensation carrier, 10...Detection carrier, 11...Oxidation catalyst, 12...Compensator, 1
4, 15... Input terminal, 16, 17... Resistance element, 18... Second series two sides, 19, 20... Output terminal.
Claims (1)
れた第１の直列２辺の両端と２つの抵抗素子が直
列に接続された第２の直列２辺の両端とを接続
し、該両接続点を入力端子とするとともに前記第
１、第２の直列２辺の中間接続点を出力端子とす
る可燃性ガス検出用ブリツジにおいて、前記ガス
検出素子を、検出熱線と、検出熱線の周囲に付着
された検出担体と、検出担体に担持され可燃性ガ
スを燃焼させる酸化触媒と、から構成し、一方、
前記補償素子を、補償熱線と、補償熱線の周囲に
付着された補償担体と、補償担体に担持された不
活性の金属酸化物からなる補償体と、から構成
し、前記補償体の色を酸化触媒の色に近似させる
ことにより、可燃性ガス検出用ブリツジの入力電
圧の変化に対する補償熱線の抵抗値の変化を前記
入力電圧の変化に対する検出熱線の抵抗値の変化
に近似させるようにしたことを特徴とする可燃性
ガス検出用ブリツジ。1 Connect both ends of the first two series sides in which the gas detection element and the compensation element are connected in series to both ends of the second series two sides in which the two resistance elements are connected in series, and connect the two connection points. In a bridge for combustible gas detection, which has an input terminal and an intermediate connection point between the first and second series sides as an output terminal, the gas detection element is attached to a detection hot wire and a wire attached around the detection hot wire. It is composed of a detection carrier and an oxidation catalyst supported on the detection carrier and burns the combustible gas, and on the other hand,
The compensation element includes a compensation hot wire, a compensation carrier attached around the compensation hot wire, and a compensation body made of an inert metal oxide supported on the compensation carrier, and the color of the compensation body is oxidized. By approximating the color of the catalyst, the change in the resistance value of the compensation hot wire in response to a change in the input voltage of the combustible gas detection bridge is approximated to the change in the resistance value of the detection hot wire in response to a change in the input voltage. Features: A bridge for detecting flammable gases.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7497083A JPS59200949A (en) | 1983-04-28 | 1983-04-28 | Bridge for detecting inflammable gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7497083A JPS59200949A (en) | 1983-04-28 | 1983-04-28 | Bridge for detecting inflammable gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59200949A JPS59200949A (en) | 1984-11-14 |
| JPH0259949B2 true JPH0259949B2 (en) | 1990-12-13 |
Family
ID=13562655
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7497083A Granted JPS59200949A (en) | 1983-04-28 | 1983-04-28 | Bridge for detecting inflammable gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59200949A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005098405A1 (en) * | 2004-03-30 | 2005-10-20 | Citizen Watch Co., Ltd. | Heater coil for gas sensor, detection element for gas sensor, contact combustion type gas sensor, and method for manufacturing contact combustion type gas sensor |
| JP2006337243A (en) * | 2005-06-03 | 2006-12-14 | Citizen Watch Co Ltd | Catalytic combustion type gas sensor |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5739341A (en) * | 1980-08-22 | 1982-03-04 | Toyota Motor Corp | Oxygen sensor |
| JPS5752987A (en) * | 1980-09-13 | 1982-03-29 | Kenji Minami | Commodity price deciding device |
-
1983
- 1983-04-28 JP JP7497083A patent/JPS59200949A/en active Granted
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005098405A1 (en) * | 2004-03-30 | 2005-10-20 | Citizen Watch Co., Ltd. | Heater coil for gas sensor, detection element for gas sensor, contact combustion type gas sensor, and method for manufacturing contact combustion type gas sensor |
| US7713480B2 (en) | 2004-03-30 | 2010-05-11 | Citizen Holdings Co., Ltd. | Heater coil for gas sensor, detection element for gas sensor, contact combustion type gas sensor, and method for manufacturing contact combustion type gas sensor |
| US8246913B2 (en) | 2004-03-30 | 2012-08-21 | Citizen Holdings Co., Ltd. | Heater coil for gas sensor, detecting element for gas sensor, catalytic combustion gas sensor, and manufacturing method of catalytic combustion gas sensor |
| US8257656B2 (en) | 2004-03-30 | 2012-09-04 | Citizen Holdings Co., Ltd. | Heater coil for gas sensor, detecting element for gas sensor, catalytic combustion gas sensor, and manufacturing method of catalytic combustion gas sensor |
| JP2006337243A (en) * | 2005-06-03 | 2006-12-14 | Citizen Watch Co Ltd | Catalytic combustion type gas sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59200949A (en) | 1984-11-14 |
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