JP3890944B2

JP3890944B2 - Gas equipment combustion detector

Info

Publication number: JP3890944B2
Application number: JP2001310920A
Authority: JP
Inventors: 隆小松; 義明崎田; 彰荘司
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2001-10-09
Filing date: 2001-10-09
Publication date: 2007-03-07
Anticipated expiration: 2021-10-09
Also published as: JP2003120928A

Description

【０００１】
【発明の属する技術分野】
本発明は、都市ガス、プロパンガスなどを機体内で燃焼し、熱風を回転ドラム内に供給して衣類を乾燥するガス衣類乾燥機などのガス機器の燃焼検知装置に関するものである。
【０００２】
【従来の技術】
従来、この種のガス機器の燃焼検知装置においては、熱源となるガス燃焼部の温度を温度検知手段を構成する熱電対により検知し、この熱電対の出力を演算増幅器（オペアンプ）にて増幅する方式が主流である。なぜなら、熱電対の出力電圧は一般に数ミリボルトと非常に小さいためであり、その微小な電圧を、入力インピーダンスの大きな演算増幅器に入力するため、その間の回路にはほとんど電流が流れていなかった。
【０００３】
【発明が解決しようとする課題】
このような従来のガス機器の燃焼検知装置では、熱電対（温度検知手段）と演算増幅器との接続にコネクタを用いるのが一般的で、その場合に、コネクタの端子にもほとんど電流を流さない条件で使用することになり、電圧も低く電流も微小であるため、コネクタが接触不良を起こしやすいという問題があった。
【０００４】
また、そのコネクタの接触不良や外れなどにより、熱電対と回路（演算増幅器）の接続がオープンになった場合でも、従来回路の構成では実際に着火させてみるまでその異常がわからず、例えばそのセンサーが直接炎を検知するのではなく、補助的に使われていた場合、異常の検知がさらに遅くなってしまうなどの問題があった。
【０００５】
本発明は上記従来の課題を解決するもので、温度検知手段を構成する熱電対と演算増幅器とをコネクタで結ばれている場合でも、コネクタに少量ながらも電流を流し、コネクタの接触不良を防止することを目的としている。
【０００６】
【課題を解決するための手段】
本発明は上記目的を達成するために、熱源となるガス燃焼部の温度を検知する温度検知手段の出力を増幅手段により増幅し、増幅手段の出力を制御手段に入力して所定のシーケンスに従ってガス機器の運転を制御するよう構成し、増幅手段は、温度検知手段の出力を演算増幅器の２つの入力端子に接続し、回路電源のプラス側と温度検知手段のプラス側端子間に第１の抵抗器、温度検知手段のプラス側端子とマイナス側端子間に第２の抵抗器、温度検知手段のマイナス側端子と回路電源のグランド電位との間に第３の抵抗器をそれぞれ接続し、第１の抵抗器と第２の抵抗器と第３の抵抗器とで直列回路を形成し、温度検知手段の端子の一端または両端が接続されていない場合に、第２の抵抗器の両端に生ずる電圧が、温度検知手段の接続が正常なときに温度検知手段が発生する電圧よりも十分に高い所定の値以上なるように、第１の抵抗器、第２の抵抗器および第３の抵抗器の抵抗値を設定し、第２の抵抗器の両端に生ずる電圧が所定の値以上である場合には、温度検知手段の端子の一端または両端が接続されていないと判断し、制御手段は前記異常報知手段で報知するよう構成したものである。
【０００７】
これにより、温度検知手段を構成する熱電対と演算増幅器がコネクタで結ばれている場合でも、コネクタには少量ながらも電流を流すことができるため、コネクタの接触不良が発生するのを防止することができる。
【０００８】
【発明の実施の形態】
本発明の請求項１に記載の発明は、熱源となるガス燃焼部の温度を検知する温度検知手段と、前記温度検知手段の出力を増幅する増幅手段と、前記増幅手段の出力を入力し所定のシーケンスに従ってガス機器の運転を制御する制御手段と、前記制御手段に接続した異常報知手段とを備え、前記増幅手段は、前記温度検知手段の出力を演算増幅器の２つの入力端子に接続し、回路電源のプラス側と前記温度検知手段のプラス側端子間に第１の抵抗器、前記温度検知手段のプラス側端子とマイナス側端子間に第２の抵抗器、前記温度検知手段のマイナス側端子と前記回路電源のグランド電位との間に第３の抵抗器をそれぞれ接続し、前記第１の抵抗器と第２の抵抗器と第３の抵抗器とで直列回路を形成し、前記温度検知手段の端子の一端または両端が接続されていない場合に、前記第２の抵抗器の両端に生ずる電圧が、前記温度検知手段の接続が正常なときに前記温度検知手段が発生する電圧よりも十分に高い所定の値以上なるように、前記第１の抵抗器、第２の抵抗器および第３の抵抗器の抵抗値を設定し、前記第２の抵抗器の両端に生ずる電圧が前記所定の値以上である場合には、前記温度検知手段の端子の一端または両端が接続されていないと判断し、前記制御手段は前記異常報知手段で報知するよう構成したものであり、温度検知手段を構成する熱電対に起電力が発生したときには、熱電対のプラス端子とマイナス端子の間に接続した第２の抵抗器に電流が流れるので、熱電対と演算増幅器を接続しているコネクタにも電流を流すことができ、コネクタの接触不良の発生を防止することができ、温度検知手段を構成する熱電対と演算増幅器の接続がオープンになった場合は、第２の抵抗器の両端に電圧が生ずるため、正常時との違いを検知し異常を報知することができ、しかも、着火行程に入る前に異常を検知して報知することにより、機器が不安定な状態になるのを防止することができ、もし燃焼途中で温度検知手段を構成する熱電対と演算増幅器の接続が不良になった場合でも、すぐその時点で報知することができ、機器の安全性を確保することができる。
【０００９】
【実施例】
以下、本発明の実施例について、図面を参照しながら説明する。
【００１０】
（実施例１）
図２に示すように、制御手段１は、マイクロコンピュータなどで構成し、スイッチなどで構成した入力手段２からの指示により、負荷駆動手段３を介して、たとえば送風ファンを駆動するモータ４およびガスの供給を開閉する電磁開閉弁５を駆動し、さらに点火手段６を駆動することによって、バーナー（ガス燃焼部）７に点火し、ガスを燃焼させる。
【００１１】
このとき、ガスの燃焼状態を熱電対（温度検知手段）８にて検知し、その出力電圧は一般的に微小であるため、増幅手段９により制御手段１で判定可能な電圧まで増幅して入力し、制御手段１は、その電圧が所定の値を超えると安定な燃焼状態と判定して、表示手段１０に燃焼状態を表示する。また、電源供給手段１１は、制御手段１をはじめその他の回路に低圧の直流電源を供給するものである。
【００１２】
熱電対８の出力線（プラスとマイナスの２本の線）は、図１に示すように、プリント基板上の回路に接続する際に、コネクタ１２を介して接続している。増幅手段９を構成する演算増幅器（オペアンプ）１３は熱電対８の微小な出力電圧を制御手段１により判定できる電圧まで増幅するもので、コネクタ１２を介して、熱電対８のプラス側を演算増幅器１３のプラス側入力に接続し、また熱電対８のマイナス側を同じくコネクタ１２を介して、演算増幅器１３のマイナス側入力に接続している。
【００１３】
第１の抵抗器１４は、回路電源１７（図２の電源供給手段１１から供給される低圧の直流電源で、たとえば５Ｖ）と熱電対８のプラス側端子間に接続し、第２の抵抗器１５は、熱電対８のプラス側端子とマイナス側端子間に接続し、第３の抵抗器１６は熱電対８のマイナス端子と回路電源のグランド電位（０Ｖ）１８間に接続している。帰還抵抗器１９は、演算増幅器１３の増幅率を決定するものである。
【００１４】
上記構成において動作を説明すると、バーナー７に点火すると熱電対８は熱起電力が発生し、この熱起電力を演算増幅器１３で増幅する。このとき、一般的に演算増幅器１３の入力インピーダンスは非常に大きいため、熱電対８から増幅手段９にはほとんど電流は流れないため、コネクタ１２の接触不良などによる誤動作が懸念される。
【００１５】
ここで、第２の抵抗器１５を熱電対８の出力端子間に並列に接続しているため、熱電対８からコネクタ１２を介して第２の抵抗器１５のループが形成され、コネクタ１２に電流が流れる。この電流によって、接触不良などによる誤動作を未然に防止できる。
【００１６】
このように本実施例によれば、熱電対８のプラス側およびマイナス側出力間に第２の抵抗器１５を並列接続したことにより、熱電対８を接続するコネクタ１２に電流を流して使用することができ、コネクタ１２の接触不良を未然に防ぐことができ、誤動作の発生を防止できる。
【００１７】
（実施例２）
図３に示すように、異常報知手段２０は、制御手段２１が各入力信号などに異常が発生したと判定した場合に、ガス機器の動作を安全側に停止するとともに、その異常の内容を使用者または修理担当者に知らせるものである。第２の抵抗器１５に生ずる分割電圧が所定の値以上である場合には、コネクタ１２の外れなどにより熱電対８の端子の一端または両端が接続されていないと判定し、制御手段２１は異常報知手段２０で報知するよう構成している。
【００１８】
図４は、異常が発生した場合の例として、熱電対８と増幅手段９を接続するコネクタ１２が外れてしまった場合の例を示している。図４より明らかなように、コネクタ１２が外れた場合、演算増幅器１３の入力には、回路電源１７の電圧を第１の抵抗器１４と、第２の抵抗器１５と、第３の抵抗器１６で分割し、第２の抵抗器１５の両端に発生する電圧がそのまま入力される。
【００１９】
ここで、第１の抵抗器１４を１００ｋΩ、第２の抵抗器１５を５６０Ω、第３の抵抗器１６を１ｋΩ、回路電源１７を５Ｖ、帰還抵抗１９を１００ｋΩに設定し、コネクタ１２の外れなどにより熱電対８の端子の一端または両端が接続されていない場合に、第２の抵抗器１５の両端に生ずる電圧を、熱電対８の接続が正常なときに熱電対８が発生する電圧よりも十分に高くなるようにしている。他の構成は上記実施例１と同じである。
【００２０】
上記構成において図５を参照しながら動作を説明する。図５は、時刻ｔ１で燃焼を開始し、時刻ｔ２でコネクタ１２が外れた場合の各部の電圧を示している。熱電対８の起電力Ｖｔｈは、時刻ｔ０から時刻ｔ１までの燃焼前は当然０Ｖであり、時刻ｔ１以降の燃焼中はコネクタ１２の状態によらず一定で、約１５ｍＶである。
【００２１】
第２の抵抗器１５の両端電圧Ｖ２は、コネクタ１２が正常で、時刻ｔ０から時刻ｔ１までの燃焼前は０Ｖで、燃焼中は１５ｍＶであり、時刻ｔ２でコネクタ１２が外れると、抵抗の電圧分割により２８ｍＶの電圧が発生し、コネクタ１２が正常に接続されていた場合よりも高くなる。
【００２２】
これにより、演算増幅器１３の出力電圧Ｖａは、増幅率を１００倍に設定しているので、時刻ｔ０から時刻ｔ１までの燃焼前は０Ｖで、時刻ｔ１から時刻ｔ２までの燃焼中は１．５Ｖ、時刻ｔ２以降のコネクタ１２が外れた状態では２．８Ｖとなり、演算増幅器１３の出力電圧Ｖａもコネクタ１２が外れると高くなる。
【００２３】
これを利用して、正常時とコネクタ１２が外れたときとの電圧の間に所定の値Ｖｓを設定する。いいかえれば、コネクタ１２が正常なときと外れたときとの電圧差が、所定の値Ｖｓをまたがるように第１の抵抗器１４と第２の抵抗器１５と第３の抵抗器１６の抵抗値を選ぶことによって、コネクタ１２の外れを制御手段２１で判定し、異常報知手段２０により異常の内容を使用者または修理担当者に知らせ、安全な対応を図ることができる。
【００２４】
また、上述のように定数を選ぶことによって、燃焼中の熱電対８の出力がばらついたとしても、確実に所定の値（しきい値）Ｖｓで区分けができ、異常報知の誤動作を防止することができる。
【００２５】
このように本実施例によれば、コネクタ１２が外れたときに演算増幅器１３の出力電圧が高くなることを利用して、異常の発生を確実に知らせることができ、ガス機器の安全性を高めることができる。
【００２６】
なお、本実施例では、コネクタ１２が２つの端子とも外れた場合の動作としたが、これは一方の端子が外れた場合でも、同じである。
【００２７】
（実施例３）
図３に示す制御手段２１は、燃焼行程に入る以前に熱電対８の端子の一端または両端が接続されていないことを判定し、異常報知するよう構成している。他の構成は上記実施例２と同じである。
【００２８】
上記構成において図６を参照しながら動作を説明する。図５から明らかなように、燃焼中に熱電対８の接続が外れると、演算増幅器１３の出力は所定の値Ｖｓ以上に高くなるが、これは燃焼中に限ったことではなく、本発明の構成からすれば、燃焼前でも同様である。実際に、コネクタ１２が外れるなどの異常は輸送中などで発生することが考えられ、運転初期からの故障である場合が多い。
【００２９】
したがって、図６に示すように、ステップ３１で電源を投入し、ステップ３２でスタートした後、ステップ３３にて、熱電対８の増幅後の電圧が所定の値Ｖｓを越えているかどうかを判定し、所定の値Ｖｓを越えていればステップ３４へ進み、コネクタ１２が外れているなど熱電対８の回路の異常と判断し、異常報知手段２０により異常報知し、少しでも危険な状態を避けることができる。
【００３０】
ステップ３３にて、熱電対８の増幅後の電圧が所定の値Ｖｓを越えていないときはステップ３５へ進み、点火動作を伴う通常のシーケンスを行う。
【００３１】
このように本実施例によれば、運転開始時に熱電対８の接続に異常が見られると判断したときは、点火シーケンスに移ることなく速やかに異常を知らしめることによって、ガス機器の安全性を高めることができる。
【００３２】
（実施例４）
図７に示すように、第２の熱電対（第２の温度検知手段）２２は、ガスの燃焼状態を検知するもので、その出力電圧を第２の増幅手段２３により増幅して制御手段２４に入力している。制御手段２４は、一方の熱電対、たとえば熱電対８で燃焼を検知しているにもかかわらず、他方の熱電対、すなわち第２の熱電対２２の出力が所定の値に達していないとき、異常報知手段２０にて異常を報知するよう構成している。第２の増幅手段２３の構成は、図示はしていないが、図４に示す構成と同じである。他の構成は上記実施例１または２と同じである。
【００３３】
上記構成において動作を説明する。増幅手段９と第２の増幅手段２３がともに正常であるときは、それぞれ上記実施例２で説明したように、１．５Ｖ程度の電圧を発生している。ここで、どちらかの接続が外れた場合は、上記実施例２または３のように、異常を報知できる。
【００３４】
ところが、もし一方の熱電対回路がショート状態になると、増幅手段９または第２の増幅手段２３の出力は０Ｖのままとなる。０Ｖというのは、燃焼していない状態と同じなので、熱電対回路の系統がひとつのみの場合は検知ができないが、本実施例のように、熱電対回路の系統を２つ有することにより、一方が燃焼検知中にもう一方が０ｖのままだったとすると、それは回路のショートと判断して、異常を報知することができる。
【００３５】
このように本実施例によれば、熱電対による燃焼検知の系統を２つ設けたことにより、回路の外れのみならず、ショート状態をも検知して異常を知らしめることができ、ガス機器の安全性を向上することができる。
【００３６】
【発明の効果】
以上のように本発明の請求項１に記載の発明によれば、熱源となるガス燃焼部の温度を検知する温度検知手段と、前記温度検知手段の出力を増幅する増幅手段と、前記増幅手段の出力を入力し所定のシーケンスに従ってガス機器の運転を制御する制御手段と、前記制御手段に接続した異常報知手段とを備え、前記増幅手段は、前記温度検知手段の出力を演算増幅器の２つの入力端子に接続し、回路電源のプラス側と前記温度検知手段のプラス側端子間に第１の抵抗器、前記温度検知手段のプラス側端子とマイナス側端子間に第２の抵抗器、前記温度検知手段のマイナス側端子と前記回路電源のグランド電位との間に第３の抵抗器をそれぞれ接続し、前記第１の抵抗器と第２の抵抗器と第３の抵抗器とで直列回路を形成し、前記温度検知手段の端子の一端または両端が接続されていない場合に、前記第２の抵抗器の両端に生ずる電圧が、前記温度検知手段の接続が正常なときに前記温度検知手段が発生する電圧よりも十分に高い所定の値以上なるように、前記第１の抵抗器、第２の抵抗器および第３の抵抗器の抵抗値を設定し、前記第２の抵抗器の両端に生ずる電圧が前記所定の値以上である場合には、前記温度検知手段の端子の一端または両端が接続されていないと判断し、前記制御手段は前記異常報知手段で報知するよう構成したから、温度検知手段と演算増幅器を接続しているコネクタにも電流を流すことができ、コネクタの接触不良の発生を防止することができ、温度検知手段の出力電圧を増幅する演算増幅器の出力電圧が高くなることを利用して、異常の発生を確実に知らしめることができ、機器の安全性を高めることができ、燃焼中の温度検知手段の出力がばらついたとしても、確実にしきい値で区分けができ、異常報知の誤動作を防止することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施例のガス機器の燃焼検知装置の一部ブロック化した回路図
【図２】同燃焼検知装置を備えたガス機器のブロック図
【図３】本発明の第２の実施例の燃焼検知装置を備えたガス機器のブロック図
【図４】同ガス機器の燃焼検知装置の一部ブロック化した回路図
【図５】
同ガス機器の燃焼検知装置の動作タイムチャート
【図６】本発明の第３の実施例のガス機器の燃焼検知装置の動作フローチャート
【図７】本発明の第４の実施例の燃焼検知装置を備えたガス機器のブロック図
【符号の説明】
１制御手段
７バーナー（ガス燃焼部）
８熱電対（温度検知手段）
９増幅手段
１３演算増幅器
１４第１の抵抗器
１５第２の抵抗器
１６第３の抵抗器
１７回路電源
１８グランド電位[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion detection device for a gas appliance such as a gas clothing dryer that burns city gas, propane gas, or the like in a body and supplies hot air into a rotating drum to dry clothes.
[0002]
[Prior art]
Conventionally, in this type of combustion detection device for gas equipment, the temperature of the gas combustion section serving as a heat source is detected by a thermocouple constituting the temperature detection means, and the output of this thermocouple is amplified by an operational amplifier (op amp). The method is mainstream. This is because the output voltage of the thermocouple is generally very small, such as several millivolts, and since the minute voltage is input to the operational amplifier having a large input impedance, almost no current flows in the circuit between them.
[0003]
[Problems to be solved by the invention]
In such a conventional combustion detection apparatus for gas equipment, it is common to use a connector for connection between a thermocouple (temperature detection means) and an operational amplifier. In that case, almost no current flows through the terminal of the connector. Since it is used under conditions, the voltage is low and the current is very small, there is a problem that the connector is liable to cause poor contact.
[0004]
Even if the connection between the thermocouple and the circuit (operational amplifier) is open due to poor contact or disconnection of the connector, the conventional circuit configuration does not detect the abnormality until it is actually ignited. If the sensor was not used to detect the flame directly but was used as an auxiliary, there was a problem that the detection of the anomaly became even slower.
[0005]
The present invention solves the above-described conventional problems, and even when a thermocouple and an operational amplifier constituting a temperature detecting means are connected by a connector, a small amount of current is passed through the connector to prevent contact failure of the connector. The purpose is to do.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention amplifies the output of the temperature detecting means for detecting the temperature of the gas combustion section serving as a heat source by the amplifying means, and inputs the output of the amplifying means to the control means so that the gas is supplied according to a predetermined sequence The amplifier is configured to control the operation of the device, and the amplifying unit connects the output of the temperature detecting unit to the two input terminals of the operational amplifier, and the first resistor is connected between the plus side of the circuit power supply and the plus side terminal of the temperature detecting unit. And a third resistor connected between the positive terminal and the negative terminal of the temperature detection means and a third resistor between the negative terminal of the temperature detection means and the ground potential of the circuit power source, respectively . When a series circuit is formed by the resistor, the second resistor, and the third resistor, and one or both ends of the terminals of the temperature detecting means are not connected, a voltage generated at both ends of the second resistor However, the connection of the temperature detection means is correct The resistance values of the first resistor, the second resistor, and the third resistor are set so as to be equal to or higher than a predetermined value that is sufficiently higher than the voltage generated by the temperature detection means. When the voltage generated at both ends of the resistor is equal to or higher than a predetermined value, it is determined that one or both ends of the terminal of the temperature detection means are not connected, and the control means is configured to notify the abnormality notification means . Is.
[0007]
As a result, even when the thermocouple and the operational amplifier constituting the temperature detecting means are connected by a connector, a small amount of current can flow through the connector, thus preventing a connector contact failure from occurring. Can do.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect of the present invention, there is provided temperature detection means for detecting the temperature of the gas combustion section serving as a heat source, amplification means for amplifying the output of the temperature detection means, and output from the amplification means. Control means for controlling the operation of the gas equipment according to the sequence of, and an abnormality notification means connected to the control means, the amplifying means connects the output of the temperature detection means to the two input terminals of the operational amplifier, A first resistor between the plus side of the circuit power supply and the plus side terminal of the temperature detection means, a second resistor between the plus side terminal and the minus side terminal of the temperature detection means, and a minus side terminal of the temperature detection means And a ground potential of the circuit power supply, respectively, a third resistor is connected, and the first resistor, the second resistor, and the third resistor form a series circuit, and the temperature detection One or both of the terminals of the means Is not connected, the voltage generated at both ends of the second resistor becomes a predetermined value that is sufficiently higher than the voltage generated by the temperature detection means when the connection of the temperature detection means is normal. Thus, when the resistance values of the first resistor, the second resistor, and the third resistor are set, and the voltage generated at both ends of the second resistor is equal to or higher than the predetermined value, , It is determined that one or both ends of the terminal of the temperature detection means are not connected, and the control means is configured to notify the abnormality notification means, and an electromotive force is generated in the thermocouple constituting the temperature detection means. When this occurs, current flows through the second resistor connected between the positive and negative terminals of the thermocouple, so that current can also flow through the connector connecting the thermocouple and the operational amplifier. Prevents poor contact Rukoto is Ki de, if the connection of the thermocouple and the operational amplifier constituting the temperature detecting means becomes open, the voltage across the second resistor occurs, the detecting the difference between the normal abnormal can be reported, yet, configuration by notifying to detect an abnormality before entering the ignition stroke, equipment Ki de be prevented from becoming unstable, if the temperature detecting means at half-burned Even if the connection between the thermocouple and the operational amplifier becomes defective, it can be immediately notified at that time, and the safety of the device can be ensured .
[0009]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0010]
Example 1
As shown in FIG. 2, the control means 1 is composed of a microcomputer or the like, and, for example, a motor 4 that drives a blower fan and gas via the load drive means 3 according to an instruction from the input means 2 that is composed of a switch or the like. By driving the electromagnetic on-off valve 5 that opens and closes the supply of the gas, and further by driving the ignition means 6, the burner (gas combustion unit) 7 is ignited to burn the gas.
[0011]
At this time, the combustion state of the gas is detected by the thermocouple (temperature detection means) 8 and the output voltage is generally very small. Therefore, the amplification means 9 amplifies and inputs the voltage that can be determined by the control means 1. The control means 1 determines that the combustion state is stable when the voltage exceeds a predetermined value, and displays the combustion state on the display means 10. The power supply means 11 supplies low-voltage DC power to the control means 1 and other circuits.
[0012]
The output lines (two plus and minus lines) of the thermocouple 8 are connected via a connector 12 when connecting to a circuit on a printed board as shown in FIG. An operational amplifier (op-amp) 13 constituting the amplification means 9 amplifies the minute output voltage of the thermocouple 8 to a voltage that can be determined by the control means 1, and the operational amplifier is connected to the plus side of the thermocouple 8 via the connector 12. 13 is connected to the plus side input of the thermocouple 8, and the minus side of the thermocouple 8 is also connected to the minus side input of the operational amplifier 13 through the connector 12.
[0013]
The first resistor 14 is connected between the circuit power supply 17 (a low-voltage DC power supply supplied from the power supply means 11 in FIG. 2, for example, 5 V) and the plus side terminal of the thermocouple 8, and the second resistor A third resistor 16 is connected between the negative terminal of the thermocouple 8 and the ground potential (0 V) 18 of the circuit power supply. The feedback resistor 19 determines the amplification factor of the operational amplifier 13.
[0014]
The operation in the above configuration will be described. When the burner 7 is ignited, the thermocouple 8 generates a thermoelectromotive force, and the thermoelectromotive force is amplified by the operational amplifier 13. At this time, since the input impedance of the operational amplifier 13 is generally very large, almost no current flows from the thermocouple 8 to the amplifying means 9, so there is a concern about malfunction due to poor contact of the connector 12.
[0015]
Here, since the second resistor 15 is connected in parallel between the output terminals of the thermocouple 8, a loop of the second resistor 15 is formed from the thermocouple 8 via the connector 12. Current flows. This current can prevent malfunctions due to poor contact.
[0016]
As described above, according to the present embodiment, the second resistor 15 is connected in parallel between the plus side and minus side outputs of the thermocouple 8, so that a current flows through the connector 12 connecting the thermocouple 8. It is possible to prevent contact failure of the connector 12 and to prevent malfunction.
[0017]
(Example 2)
As shown in FIG. 3, when the control means 21 determines that an abnormality has occurred in each input signal or the like, the abnormality notifying means 20 stops the operation of the gas equipment to the safe side and uses the contents of the abnormality. Information to repair personnel or repair personnel. If the divided voltage generated in the second resistor 15 is equal to or higher than a predetermined value, it is determined that one or both ends of the terminals of the thermocouple 8 are not connected due to disconnection of the connector 12 or the like, and the control means 21 is abnormal. The notification means 20 is configured to notify the user.
[0018]
FIG. 4 shows an example where the connector 12 connecting the thermocouple 8 and the amplifying means 9 is disconnected as an example when an abnormality has occurred. As is clear from FIG. 4, when the connector 12 is disconnected, the voltage of the circuit power supply 17 is supplied to the input of the operational amplifier 13 as the first resistor 14, the second resistor 15, and the third resistor. The voltage generated at both ends of the second resistor 15 is input as it is.
[0019]
Here, the first resistor 14 is set to 100 kΩ, the second resistor 15 is set to 560Ω, the third resistor 16 is set to 1 kΩ, the circuit power supply 17 is set to 5 V, the feedback resistor 19 is set to 100 kΩ, and the connector 12 is disconnected. When one end or both ends of the terminals of the thermocouple 8 are not connected to each other, the voltage generated at both ends of the second resistor 15 is set to be higher than the voltage generated by the thermocouple 8 when the connection of the thermocouple 8 is normal. I try to get it high enough. Other configurations are the same as those of the first embodiment.
[0020]
The operation of the above configuration will be described with reference to FIG. FIG. 5 shows the voltages of the respective parts when combustion starts at time t1 and the connector 12 is disconnected at time t2. The electromotive force Vth of the thermocouple 8 is naturally 0 V before the combustion from the time t0 to the time t1, and is constant regardless of the state of the connector 12 and about 15 mV during the combustion after the time t1.
[0021]
The voltage V2 across the second resistor 15 is 0V before combustion from time t0 to time t1, and 15 mV during combustion from time t0 to time t1, and when the connector 12 is disconnected at time t2, the resistance voltage The division generates a voltage of 28 mV, which is higher than when the connector 12 is normally connected.
[0022]
As a result, the output voltage Va of the operational amplifier 13 is set to 100 times the amplification factor, so it is 0 V before combustion from time t0 to time t1, and 1.5 V during combustion from time t1 to time t2. When the connector 12 is disconnected after time t2, the voltage becomes 2.8 V, and the output voltage Va of the operational amplifier 13 increases when the connector 12 is disconnected.
[0023]
Using this, a predetermined value Vs is set between the voltage at the normal time and when the connector 12 is disconnected. In other words, the resistance values of the first resistor 14, the second resistor 15, and the third resistor 16 so that the voltage difference between when the connector 12 is normal and when the connector 12 is disconnected exceeds the predetermined value Vs. By selecting, the disconnection of the connector 12 is determined by the control means 21, and the abnormality notification means 20 notifies the user or the person in charge of the repair of the abnormality, so that a safe response can be achieved.
[0024]
In addition, by selecting a constant as described above, even if the output of the thermocouple 8 during combustion varies, it is possible to reliably classify by the predetermined value (threshold value) Vs, and prevent malfunction of abnormality notification. Can do.
[0025]
As described above, according to this embodiment, when the connector 12 is disconnected, the output voltage of the operational amplifier 13 becomes high, so that the occurrence of an abnormality can be reliably notified and the safety of the gas equipment is improved. be able to.
[0026]
In this embodiment, the operation is performed when the connector 12 is disconnected from both of the two terminals, but this is the same even when one of the terminals is disconnected.
[0027]
(Example 3)
The control means 21 shown in FIG. 3 is configured to determine that one end or both ends of the terminals of the thermocouple 8 are not connected before entering the combustion stroke, and notify the abnormality. Other configurations are the same as those of the second embodiment.
[0028]
The operation of the above configuration will be described with reference to FIG. As is apparent from FIG. 5, when the thermocouple 8 is disconnected during combustion, the output of the operational amplifier 13 becomes higher than a predetermined value Vs, but this is not limited to during combustion. In terms of configuration, the same is true before combustion. Actually, an abnormality such as disconnection of the connector 12 may occur during transportation and is often a failure from the beginning of operation.
[0029]
Therefore, as shown in FIG. 6, after turning on the power in step 31 and starting in step 32, in step 33, it is determined whether or not the amplified voltage of the thermocouple 8 exceeds a predetermined value Vs. If the predetermined value Vs is exceeded, the process proceeds to step 34, where it is determined that the circuit of the thermocouple 8 is abnormal, such as the connector 12 being disconnected, and the abnormality notifying means 20 notifies the abnormality so as to avoid any dangerous state. Can do.
[0030]
In step 33, when the amplified voltage of the thermocouple 8 does not exceed the predetermined value Vs, the process proceeds to step 35, and a normal sequence with an ignition operation is performed.
[0031]
As described above, according to the present embodiment, when it is determined that there is an abnormality in the connection of the thermocouple 8 at the start of operation, the abnormality of the gas appliance is improved by promptly informing the abnormality without moving to the ignition sequence. Can be increased.
[0032]
Example 4
As shown in FIG. 7, the second thermocouple (second temperature detecting means) 22 detects the combustion state of the gas, and the output voltage is amplified by the second amplifying means 23 and the control means 24. Is entered. When the control means 24 detects combustion in one thermocouple, for example, the thermocouple 8, but the output of the other thermocouple, that is, the second thermocouple 22 does not reach a predetermined value, The abnormality notifying means 20 is configured to notify the abnormality. The configuration of the second amplifying means 23 is not shown, but is the same as the configuration shown in FIG. Other configurations are the same as those in the first or second embodiment.
[0033]
The operation in the above configuration will be described. When both the amplifying means 9 and the second amplifying means 23 are normal, a voltage of about 1.5 V is generated as described in the second embodiment. Here, when one of the connections is disconnected, the abnormality can be notified as in the second or third embodiment.
[0034]
However, if one of the thermocouple circuits is short-circuited, the output of the amplifying means 9 or the second amplifying means 23 remains 0V. Since 0V is the same as the state in which combustion is not performed, detection is not possible when there is only one thermocouple circuit system, but by having two thermocouple circuit systems as in this embodiment, If the other remains at 0 V during combustion detection, it is determined that the circuit is short-circuited, and an abnormality can be notified.
[0035]
Thus, according to the present embodiment, by providing two combustion detection systems using thermocouples, it is possible to detect not only a circuit disconnection but also a short-circuit state, thereby notifying an abnormality. Safety can be improved.
[0036]
【The invention's effect】
As described above, according to the first aspect of the present invention, the temperature detecting means for detecting the temperature of the gas combustion section serving as a heat source, the amplifying means for amplifying the output of the temperature detecting means, and the amplifying means The control means for controlling the operation of the gas equipment according to a predetermined sequence , and the abnormality notifying means connected to the control means, the amplifying means outputs the output of the temperature detecting means to two of the operational amplifiers Connected to the input terminal, a first resistor between the plus side of the circuit power supply and the plus side terminal of the temperature detecting means, a second resistor between the plus side terminal and the minus side terminal of the temperature detecting means, the temperature A third resistor is connected between the negative terminal of the detection means and the ground potential of the circuit power supply , and a series circuit is formed by the first resistor, the second resistor, and the third resistor. Forming the temperature sensing means When one or both ends of the child are not connected, the voltage generated at both ends of the second resistor is sufficiently higher than the voltage generated by the temperature detecting means when the connection of the temperature detecting means is normal. The resistance values of the first resistor, the second resistor, and the third resistor are set so as to be equal to or higher than a predetermined value, and a voltage generated at both ends of the second resistor is equal to or higher than the predetermined value. If it is, it is determined that one or both ends of the terminal of the temperature detecting means are not connected, and the control means is configured to notify the abnormality notifying means, so the temperature detecting means and the operational amplifier are connected. also it is possible to flow electric current to the connector and can prevent contact defective connector, by utilizing the fact that the output voltage of the operational amplifier for amplifying the output voltage of the temperature detection means becomes higher, the abnormality of Make sure you know the outbreak Can Mel, Ki out to enhance the safety of the equipment, even when variations in the output of the temperature detecting means during combustion, can be reliably divided by the threshold, it is possible to prevent malfunction of the abnormality notification .
[ Brief description of the drawings]
FIG. 1 is a partial block circuit diagram of a combustion detector for a gas appliance according to a first embodiment of the present invention. FIG. 2 is a block diagram of a gas appliance equipped with the combustion detector. FIG. 4 is a block diagram of a gas device provided with the combustion detection device of the second embodiment.
Operation time chart of combustion detector of gas equipment FIG. 6 Flow chart of operation of combustion detector of gas equipment of the third embodiment of the present invention FIG. 7 Combustion detector of the fourth embodiment of the present invention Block diagram of equipped gas equipment [Explanation of symbols]
1 Control means 7 Burner (gas combustion section)
8 Thermocouple (Temperature detection means)
DESCRIPTION OF SYMBOLS 9 Amplifying means 13 Operational amplifier 14 1st resistor 15 2nd resistor 16 3rd resistor 17 Circuit power supply 18 Ground potential

Claims

Temperature detection means for detecting the temperature of the gas combustion section as a heat source, amplification means for amplifying the output of the temperature detection means, and control means for inputting the output of the amplification means and controlling the operation of the gas equipment according to a predetermined sequence And an abnormality notifying means connected to the control means , wherein the amplifying means connects the output of the temperature detecting means to two input terminals of an operational amplifier, and connects the plus side of the circuit power supply and the plus of the temperature detecting means. A first resistor between the side terminals, a second resistor between the positive and negative terminals of the temperature detection means, and a second resistor between the negative terminal of the temperature detection means and the ground potential of the circuit power supply. 3 of resistors connected respectively, wherein the series circuit formed by a first resistor and a second resistor and a third resistor, one end or both ends of the terminals of the temperature sensing means is connected If you do not, the The voltage developed across the second resistor, wherein such connecting temperature sensing means said temperature detecting means is sufficiently high not larger than a predetermined value than the voltage generated when normal, the first resistor When the resistance values of the second resistor and the third resistor are set and the voltage generated at both ends of the second resistor is equal to or higher than the predetermined value, one end of the terminal of the temperature detecting means Or it is judged that both ends are not connected, and the said control means is a combustion detection apparatus of the gas equipment comprised so that it might alert | report by the said abnormality alerting means .