JP3921167B2

JP3921167B2 - Gas alarm

Info

Publication number: JP3921167B2
Application number: JP2002362418A
Authority: JP
Inventors: 計望月; 義昭石黒
Original assignee: Yazaki Corp
Current assignee: Yazaki Corp
Priority date: 2002-12-13
Filing date: 2002-12-13
Publication date: 2007-05-30
Anticipated expiration: 2022-12-13
Also published as: JP2004192531A

Description

【０００１】
【発明の属する技術分野】
本発明は、ガス警報器に関し、特に通常動作モードおよび点検動作モードを有するガス警報器に関する。
【０００２】
【従来の技術】
通常、ガス警報器に用いられるセンサとしては、接触燃焼式や半導体式のガスセンサが一般的である。接触燃焼式ガスセンサは、通常、２０〜５０μｍの細い白金線をコイル状に形成し、そのコイル上に触媒を塗布、乾燥、焼成を行い、ガスセンサとしている。
【０００３】
このガスセンサによるガス検知は、都市ガスあるいはＬＰガスが存在すると、その中に含まれるメタン、イソブタン、水素と触媒との反応熱で、白金コイルの抵抗値が上昇する原理を利用している。半導体式ガスセンサは、接触燃焼式ガスセンサと同様に、コイル上に触媒を塗布、乾燥、焼成を行い、ガスセンサとしている。半導体式ガスセンサの半導体表面にガスが接触すると、半導体と吸着分子との間に電子の授受が起こり、その電気伝導度が変化するので、この電気伝導度の変化を検出することにより、ガスを検知することができる。
【０００４】
【発明が解決しようとする課題】
都市ガスまたはＬＰガスの検知と、不完全燃焼ガスの検知、火災の検知を組み合わせた複合型警報器においては、ユーザ宅への設置時、センサ特性を確認するため、ライター等の生ガスや一酸化炭素ガスを用いて点検を行う。現行警報器の場合、機種によっても異なるが、たとえば、電源投入後１０分間は点検モードとしているので、点検作業に時間がかかるという問題がある。
【０００５】
また、点検モードの間センサがある設定点以上のガスに反応すると、遅延を無視し即鳴動する。その際、過度にセンサへガスを吹きかけると、センサ内部にある活性炭にこれらのガスが吸着し、点検終了後も鳴り止まないという問題が生じる。また、仮に鳴り止んだとしても、作業終了後、活性炭に吸着したガスが徐々に離脱し、再鳴動してしまう危険性もある。
【０００６】
そこで本発明は、上述した点検動作モード時の従来の問題点に鑑み、点検作業時間を短縮することができ、点検用ガスによる過度の影響を低減することができるガス警報器を提供することを目的としている。
【０００７】
【課題を解決するための手段】
上記課題を解決するためになされた請求項１記載の発明は、図１の基本構成図に示すように、ガスセンサの温度を低温域と高温域に周期的に交互に変化させ、低温域または高温域のいずれか一方のガス濃度の検出期間において、ガスセンサ１２で検出されたガス濃度が所定の警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知するガス警報器において、通常動作モードと点検動作モードを切り換え制御する動作モード制御手段１６であって、通常動作モード時には、ガス濃度の検出期間中の１つの検出ポイントにおいて上記ガスセンサ１２でガス濃度を検出し、検出されたガス濃度が警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知すると共に、点検動作モード時には、ガス濃度の検出期間の始めから終わりまで常に前記ガスセンサ１２でガス濃度を検出し、検出されたガス濃度が警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知する動作モード制御手段１６を備えたことを特徴とするガス警報器に存する。
【０００８】
請求項１記載の発明によれば、ガスセンサの温度を低温域と高温域に周期的に交互に変化させ、低温域または高温域のいずれか一方のガス濃度の検出期間において、ガスセンサ１２で検出されたガス濃度が所定の警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知するガス警報器において、通常動作モードと点検動作モードを切り換え制御する動作モード制御手段１６であって、通常動作モード時には、ガス濃度の検出期間中の１つの検出ポイントにおいてガスセンサ１２でガス濃度を検出し、検出されたガス濃度が警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知すると共に、点検動作モード時には、ガス濃度の検出期間の始めから終わりまで常にガスセンサ１２でガス濃度を検出し、検出されたガス濃度が警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知する動作モード制御手段１６を備えているので、従来より点検作業を短時間に行うことができる。
【０００９】
上記課題を解決するためになされた請求項２記載の発明は、前記動作モード制御手段１６は、点検動作モード時には、ガス濃度の検出期間の始めから終わりまで常に前記ガスセンサ１２でガス濃度を検出し、検出されたガス濃度が警報濃度以上となった際に、ガス濃度が異常となった旨の警報を開始し、所定時間経過後強制的に警報を停止することを特徴とする請求項１記載のガス警報器に存する。
【００１０】
請求項２記載の発明によれば、動作モード制御手段１６は、点検動作モード時には、ガス濃度の検出期間の始めから終わりまで常にガスセンサ１２でガス濃度を検出し、検出されたガス濃度が警報濃度以上となった際に、ガス濃度が異常となった旨の警報を開始し、所定時間経過後強制的に警報を停止するので、従来より点検作業を短時間に行うことができる。
【００１１】
上記課題を解決するためになされた請求項３記載の発明は、ガスセンサの温度を低温域と高温域に周期的に交互に変化させ、低温域または高温域のいずれか一方のガス濃度の検出期間において、ガスセンサ１２で検出されたガス濃度が所定の警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知するガス警報器において、通常動作モードと点検動作モードを切り換え制御する動作モード制御手段１６であって、通常動作モード時には、ガス濃度の検出期間中の１つの検出ポイントで前記ガスセンサでガス濃度を検出し、検出されたガス濃度が通常動作モード用警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知すると共に、点検動作モード時には、ガス濃度の検出期間の始めから終わりまで常に前記ガスセンサ１２でガス濃度を検出し、検出されたガス濃度が通常動作モード用警報濃度より低く設定された点検モード用警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知する動作モード制御手段１６を備えたことを特徴とするガス警報器に存する。
【００１２】
請求項３記載の発明によれば、ガスセンサの温度を低温域と高温域に周期的に交互に変化させ、低温域または高温域のいずれか一方のガス濃度の検出期間において、ガスセンサ１２で検出されたガス濃度が所定の警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知するガス警報器において、通常動作モードと点検動作モードを切り換え制御する動作モード制御手段１６であって、通常動作モード時には、ガス濃度の検出期間中の１つの検出ポイントでガスセンサでガス濃度を検出し、検出されたガス濃度が通常動作モード用警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知すると共に、点検動作モード時には、ガス濃度の検出期間の始めから終わりまで常にガスセンサ１２でガス濃度を検出し、検出されたガス濃度が通常動作モード用警報濃度より低く設定された点検モード用警報濃度以上となった際に、ガス濃度が異常となった旨の警報を報知する動作モード制御手段１６を備えているので、低濃度のガスで従来より点検作業を短時間に行うことができ、また警報を報知された時点で点検用ガスをガスセンサから遠ざけることにより高濃度ガスにガスセンサがさらされないようにして、従来のような点検時の警報手段の鳴動持続や再鳴動を回避することが可能となる。
【００１３】
上記課題を解決するためになされた請求項４記載の発明は、前記動作モード制御手段１６は、点検動作モード時には、ガス濃度の検出期間の始めから終わりまで常に前記ガスセンサ１２でガス濃度を検出し、検出されたガス濃度が通常動作モード用警報濃度より低く設定された点検モード用警報濃度以上となった際に、ガス濃度が異常となった旨の警報を開始し、所定時間経過後強制的に警報を停止することを特徴とする請求項３記載のガス警報器に存する。
【００１４】
請求項４記載の発明によれば、動作モード制御手段１６は、点検動作モード時には、ガス濃度の検出期間の始めから終わりまで常にガスセンサ１２でガス濃度を検出し、検出されたガス濃度が通常動作モード用警報濃度より低く設定された点検モード用警報濃度以上となった際に、ガス濃度が異常となった旨の警報を開始し、所定時間経過後強制的に警報を停止するので、従来より点検作業を短時間に行うことができる。
【００１５】
上記課題を解決するためになされた請求項５記載の発明は、前記ガスセンサ１２は、２種類のガス１１Ａ，１１Ｂに対するガス濃度を検出してガス濃度信号１２ａを生成するセンサ素子１２４と、該センサ素子１２４を加熱するヒータ１２２とを有することを特徴とする請求項１から４のいずれか１項に記載のガス警報器に存する。
【００１６】
請求項５記載の発明によれば、ガスセンサ１２は、２種類のガス１１Ａ，１１Ｂに対するガス濃度を検出してガス濃度信号１２ａを生成するセンサ素子１２４と、センサ素子１２４を加熱するヒータ１２２とを有するので、１つのガスセンサで複数種類のガスに対するガス濃度を検出することができる。
【００１７】
上記課題を解決するためになされた請求項６記載の発明は、前記ガス濃度の検出期間中に前記２種類のガス１１Ａ，１１Ｂのそれぞれに対応して前記センサ素子１２４を加熱するための第１ガスモード加熱信号１６ａおよび第２ガスモード加熱信号１６ｂを生成する前記動作モード制御手段１６と、前記第１ガスモード加熱信号１６ａまたは前記第２ガスモード加熱信号１６ｂに基づいて、前記ヒータ１２２を作動するための加熱信号１４ａを生成する加熱駆動手段１４とを有することを特徴とする請求項５記載のガス警報器に存する。
【００１８】
請求項６記載の発明によれば、ガス濃度の検出期間中に２種類のガス１１Ａ，１１Ｂのそれぞれに対応してセンサ素子１２４を加熱するための第１ガスモード加熱信号１６ａおよび第２ガスモード加熱信号１６ｂを生成する前記動作モード制御手段１６と、第１ガスモード加熱信号１６ａまたは第２ガスモード加熱信号１６ｂに基づいて、ヒータ１２２を作動するための加熱信号１４ａを生成する加熱駆動手段１４とを有するので、ガスセンサ１２のヒータ１２２を２種類のガスのそれぞれの適正温度まで加熱することができる。
【００１９】
上記課題を解決するためになされた請求項７記載の発明は、前記動作モード制御手段１６は、通常動作モード時には、前記第１ガスモード加熱信号１６ａが印加されている間または前記第２ガスモード加熱信号１６ｂが印加されている間のの１つの検出ポイントで、前記ガスセンサ１２における前記ガス濃度信号１２ａの生成を命令するためのイネーブル信号１６ｅを生成すると共に、点検動作モード時には、前記第１ガスモード加熱信号１６ａが印加されている間および前記第２ガスモード加熱信号１６ｂが印加されている間の始めから終わりまで常に、前記ガスセンサ１２における前記ガス濃度信号１２ａの生成を命令するためのイネーブル信号１６ｅを生成するセンサ制御部１６２を有することを特徴とする請求項５記載のガス警報器に存する。
【００２０】
請求項７記載の発明によれば、動作モード制御手段１６は、通常動作モード時には、第１ガスモード加熱信号１６ａが印加されている間または第２ガスモード加熱信号１６ｂが印加されている間のの１つの検出ポイントで、ガスセンサ１２におけるガス濃度信号１２ａの生成を命令するためのイネーブル信号１６ｅを生成すると共に、点検動作モード時には、第１ガスモード加熱信号１６ａが印加されている間および第２ガスモード加熱信号１６ｂが印加されている間の始めから終わりまで常に、ガスセンサ１２におけるガス濃度信号１２ａの生成を命令するためのイネーブル信号１６ｅを生成するセンサ制御部１６２を有するので、所定のタイミングでガス濃度信号を生成して、検出ミスが発生しないようにすることができ、また短時間で点検を確認することができる。
【００２１】
上記課題を解決するためになされた請求項８記載の発明は、前記ガスセンサ１２の温度を低温域と高温域に周期的に交互に変化させ、低温域で第１ガス１１Ａの第１ガス濃度を検出し、さらに高温域で第２ガス１１Ｂの第２ガス濃度を検出すると共に、第１ガス濃度が第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を報知し、第２ガス濃度が第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を報知する前記ガス警報器において、前記動作モード制御手段１６は、通常動作モード時には、第１ガス濃度の検出期間中の１つの検出ポイントにおいて前記ガスセンサ１２で第１ガス濃度を検出し、検出された第１ガス濃度が第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を報知し、かつ、第２ガス濃度の検出期間中の１つの検出ポイントにおいて前記ガスセンサ１２で第２ガス濃度を検出し、検出された第２ガス濃度が第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を報知すると共に、点検動作モード時には、第１ガス濃度の検出期間の始めから終わりまで常に前記ガスセンサ１２で第１ガス濃度を検出し、検出された第１ガス濃度が第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を開始し、所定時間経過後強制的に第１警報を停止し、かつ、第２ガス濃度の検出期間の始めから終わりまで常に前記ガスセンサ１２で第２ガス濃度を検出し、検出された第２ガス濃度が第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を開始し、所定時間経過後強制的に第２警報を停止することを特徴とする請求項５から７のいずれか１項に記載のガス警報器に存する。
【００２２】
請求項８記載の発明によれば、ガスセンサ１２の温度を低温域と高温域に周期的に交互に変化させ、低温域で第１ガス１１Ａの第１ガス濃度を検出し、さらに高温域で第２ガス１１Ｂの第２ガス濃度を検出すると共に、第１ガス濃度が第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を報知し、第２ガス濃度が第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を報知するガス警報器において、動作モード制御手段１６は、通常動作モード時には、第１ガス濃度の検出期間中の１つの検出ポイントにおいてガスセンサ１２で第１ガス濃度を検出し、検出された第１ガス濃度が第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を報知し、かつ、第２ガス濃度の検出期間中の１つの検出ポイントにおいてガスセンサ１２で第２ガス濃度を検出し、検出された第２ガス濃度が第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を報知すると共に、点検動作モード時には、第１ガス濃度の検出期間の始めから終わりまで常にガスセンサ１２で第１ガス濃度を検出し、検出された第１ガス濃度が第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を開始し、所定時間経過後強制的に第１警報を停止し、かつ、第２ガス濃度の検出期間の始めから終わりまで常にガスセンサ１２で第２ガス濃度を検出し、検出された第２ガス濃度が第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を開始し、所定時間経過後強制的に第２警報を停止するので、従来より点検作業を短時間に行うことができる。
【００２３】
上記課題を解決するためになされた請求項９記載の発明は、前記ガスセンサ１２の温度を低温域と高温域に周期的に交互に変化させ、低温域で第１ガス１１Ａの第１ガス濃度を検出し、さらに高温域で第２ガス１１Ｂの第２ガス濃度を検出すると共に、第１ガス濃度が第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を報知し、第２ガス濃度が第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を報知する前記ガス警報器において、前記動作モード制御手段１６は、通常動作モード時には、第１ガス濃度の検出期間中の１つの検出ポイントにおいて前記ガスセンサ１２で第１ガス濃度を検出し、検出された第１ガス濃度が通常動作モード用第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を報知し、かつ、第２ガス濃度の検出期間中の１つの検出ポイントにおいて前記ガスセンサ１２で第２ガス濃度を検出し、検出された第２ガス濃度が通常動作モード用第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を報知すると共に、点検動作モード時には、第１ガス濃度の検出期間の始めから終わりまで常に前記ガスセンサ１２で第１ガス濃度を検出し、検出された第１ガス濃度が通常動作モード用第１ガス警報濃度より低く設定された点検動作モード用第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を開始し、所定時間経過後強制的に第１警報を停止し、かつ、第２ガス濃度の検出期間の始めから終わりまで常に前記ガスセンサ１２で第２ガス濃度を検出し、検出された第２ガス濃度が通常動作モード用第２ガス警報濃度より低く設定された点検動作モード用第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を開始し、所定時間経過後強制的に第２警報を停止することを特徴とする請求項５から７のいずれか１項に記載のガス警報器に存する。
【００２４】
請求項９記載の発明によれば、ガスセンサ１２の温度を低温域と高温域に周期的に交互に変化させ、低温域で第１ガス１１Ａの第１ガス濃度を検出し、さらに高温域で第２ガス１１Ｂの第２ガス濃度を検出すると共に、第１ガス濃度が第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を報知し、第２ガス濃度が第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を報知する前記ガス警報器において、動作モード制御手段１６は、通常動作モード時には、第１ガス濃度の検出期間中の１つの検出ポイントにおいてガスセンサ１２で第１ガス濃度を検出し、検出された第１ガス濃度が通常動作モード用第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を報知し、かつ、第２ガス濃度の検出期間中の１つの検出ポイントにおいてガスセンサ１２で第２ガス濃度を検出し、検出された第２ガス濃度が通常動作モード用第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を報知すると共に、点検動作モード時には、第１ガス濃度の検出期間の始めから終わりまで常にガスセンサ１２で第１ガス濃度を検出し、検出された第１ガス濃度が通常動作モード用第１ガス警報濃度より低く設定された点検動作モード用第１ガス警報濃度以上となった際に、第１ガス濃度が異常となった旨の第１警報を開始し、所定時間経過後強制的に第１警報を停止し、かつ、第２ガス濃度の検出期間の始めから終わりまで常にガスセンサ１２で第２ガス濃度を検出し、検出された第２ガス濃度が通常動作モード用第２ガス警報濃度より低く設定された点検動作モード用第２ガス警報濃度以上となった際に、第２ガス濃度が異常となった旨の第２警報を開始し、所定時間経過後強制的に第２警報を停止するので、低濃度のガスで従来より点検作業を短時間に行うことができ、また警報を報知された時点で点検用ガスをガスセンサから遠ざけることにより高濃度ガスにガスセンサがさらされないようにして、従来のような点検時の警報手段の鳴動持続や再鳴動を回避することが可能となる。
【００２５】
上記課題を解決するためになされた請求項１０記載の発明は、前記動作モード制御手段１６は、前記第１ガス濃度の検出期間中に前記センサ素子１２４を前記低温域に加熱するための前記第１ガスモード加熱信号１６ａを生成し、前記第２ガス濃度の検出期間中に前記センサ素子１２４を前記高温域に加熱するための前記第２ガスモード加熱信号１６ｂを生成するように構成されていることを特徴とする請求項８または９記載のガス警報器に存する。
【００２６】
請求項１０記載の発明によれば、動作モード制御手段１６は、第１ガス濃度の検出期間中にセンサ素子１２４を低温域に加熱するための第１ガスモード加熱信号１６ａを生成し、第２ガス濃度の検出期間中にセンサ素子１２４を高温域に加熱するための第２ガスモード加熱信号１６ｂを生成するように構成されているので、ガスセンサのヒータを２種類のガスのそれぞれの適正温度まで加熱するように制御することができる。
【００２７】
上記課題を解決するためになされた請求項１１記載の発明は、前記センサ制御部１６２は、通常動作モード時には、前記第１ガス濃度の検出期間中に前記第１ガス１１Ａに係る前記第１ガスモード加熱信号１６ａが印加されている間の１つの検出ポイントでまたは前記第２ガス濃度の検出期間中に前記第２ガス１１Ｂに係る前記第２ガスモード加熱信号１６ｂが印加されている間の１つの検出ポイントで、前記ガスセンサ１２における前記第１ガス１１Ａまたは第２ガス１１Ｂに係る前記ガス濃度信号１２ａの生成を命令するための前記イネーブル信号１６ｅを生成すると共に、点検動作モード時には、前記第１ガス濃度の検出期間中に前記第１ガス１１Ａに係る前記第１ガスモード加熱信号１６ａが印加されている間の始めから終わりまで常にまたは前記第２ガス濃度の検出期間中に前記第２ガス１１Ｂに係る前記第２ガスモード加熱信号１６ｂが印加されている間の始めから終わりまで常に、前記ガスセンサ１２における前記第１ガス１１Ａまたは第２ガス１１Ｂに係る前記ガス濃度信号１２ａの生成を命令するための前記イネーブル信号１６ｅを生成するように構成されていることを特徴とする請求項８から１０のいずれか１項に記載のガス警報器に存する。
【００２８】
請求項１１記載の発明によれば、センサ制御部１６２は、通常動作モード時には、第１ガス濃度の検出期間中に第１ガス１１Ａに係る第１ガスモード加熱信号１６ａが印加されている間の１つの検出ポイントでまたは第２ガス濃度の検出期間中に第２ガス１１Ｂに係る第２ガスモード加熱信号１６ｂが印加されている間の１つの検出ポイントで、ガスセンサ１２における第１ガス１１Ａまたは第２ガス１１Ｂに係るガス濃度信号１２ａの生成を命令するためのイネーブル信号１６ｅを生成すると共に、点検動作モード時には、第１ガス濃度の検出期間中に第１ガス１１Ａに係る第１ガスモード加熱信号１６ａが印加されている間の始めから終わりまで常にまたは第２ガス濃度の検出期間中に第２ガス１１Ｂに係る第２ガスモード加熱信号１６ｂが印加されている間の始めから終わりまで常に、ガスセンサ１２における第１ガス１１Ａまたは第２ガス１１Ｂに係るガス濃度信号１２ａの生成を命令するためのイネーブル信号１６ｅを生成するように構成されているので、所定のタイミングでガス濃度信号を生成して、検出ミスが発生しないようにすることができ、また短時間で点検を確認することができる。
【００２９】
上記課題を解決するためになされた請求項１２記載の発明は、前記動作モード制御手段１６は、電源オン時にガス警報器１０を所定時間の間点検動作モードで動作させ、上記所定時間経過後前記ガス警報器１０を点検動作モードから通常動作モードに切り換えて動作させることを特徴とする請求項１から１１のいずれか１項に記載のガス警報器に存する。
【００３０】
請求項１２記載の発明によれば、動作モード制御手段１６は、電源オン時にガス警報器１０を所定時間の間点検動作モードで動作させ、所定時間経過後ガス警報器１０を点検動作モードから通常動作モードに切り換えて動作させるので、ガス警報器を設置場所への取り付け時に、通常動作を行わせる前に短時間で点検を行うことができる。
【００３１】
上記課題を解決するためになされた請求項１３記載の発明は、前記動作モード制御手段１６は、電源オン時にガス警報器１０を点検動作モードで動作させ、上記点検動作モードにおける警報停止後通常動作モードに切り換えて動作させることを特徴とする請求項１または２記載のガス警報器に存する。
【００３２】
請求項１３記載の発明によれば、動作モード制御手段１６は、電源オン時にガス警報器１０を点検動作モードで動作させ、上記点検動作モードにおける警報停止後通常動作モードに切り換えて動作させるので、ガス警報器を設置場所への取り付け時に、通常動作を行わせる前に、低濃度のガスで点検を行うことができると共に、点検時間を大幅に短縮することができる。
【００３３】
【発明の実施の形態】
以下、本発明の実施の形態について図面に基づいて説明する。まず、本発明の第１の実施形態について説明する。
【００３４】
図２は、本発明に係るガス警報器の第１の実施形態を示す回路図である。以下の説明では、第１ガス１１Ａとして一酸化炭素（ＣＯ）ガス、第２ガス１１Ｂとして都市ガス中に含まれるメタン（ＣＨ₄）ガスのガス検知を行うガス警報器１０として、特に、ガスセンサ１２の温度を低温域と高温域に周期的に交互に変化させ、低温域で第１ガス１１Ａ（すなわち、ＣＯガス）の第１ガス濃度Ｃ１を検出し、さらに、高温域で第２ガス１１Ｂ（すなわち、ＣＨ₄ガス）の第２ガス濃度Ｃ２を検出すると共に、第１ガス濃度Ｃ１が所定の第１ガス警報濃度Ａ１以上となった際に、第１ガス濃度Ｃ１が異常となった旨の第１警報を報知し、第２ガス濃度Ｃ２が所定の第２ガス警報濃度Ａ２以上となった際に、第２ガス濃度Ｃ２が異常となった旨の第２警報を報知するガス検知装置１０を実施形態として、図２を参照して説明する。
【００３５】
図２のガス警報器１０は、ガスセンサ１２、加熱駆動手段１４、動作モード制御手段１６および警報手段１８を有する。
【００３６】
本実施形態のガス警報器１０は、具体的には、ガスセンサ１２の温度を、７０乃至１００℃程度が５〜２０秒程度継続する低温域と、３５０乃至４００℃程度が３〜５秒程度継続する高温域とに周期的に交互に変化させ、このような低温域で第１ガス（ＣＯガス）１１Ａの第１ガス濃度Ｃ１（単位は［ｐｐｍ］）を検出し、さらに前述の高温域で第２ガス１１Ｂ（ＣＨ₄ガス）の第２ガス濃度Ｃ２（単位は［ｐｐｍ］）を検出すると共に、検出したＣＯガスの濃度（単位は［ｐｐｍ］）が所定の第１ガス警報濃度Ａ１以上となった際に、ＣＯガスが異常となった旨の第１警報を報知し、同様に、検出したＣＨ₄ガスの濃度が所定の第２ガス警報濃度Ａ２以上となった際に、ＣＨ₄ガス濃度が異常となった旨の第２警報を報知する機能を有する。
【００３７】
また、ガス警報器１０は、通常動作モードと点検動作モードとを有する。
【００３８】
ガスセンサ１２は、一例として、ＣＯガス１１ＡおよびＣＨ₄ガス１１Ｂを１つのセンサで検知するタイプ（ＣＯ／ＣＨ₄センサ）のガスセンサであって、ヒータ１２２とセンサ素子１２４を有する。ヒータ１２２は、その一端が加熱駆動手段１４のｐｎｐ型トランジスタＱ１のコレクタに接続されると共に、他端が接地されている。センサ素子１２４は、動作モード制御手段１６２のＣＰＵ１６４の入力ポートＰ３に接続され、測定対象ガスのガス雰囲気（すなわち、ＣＯガス雰囲気またはＣＨ₄ガス雰囲気）に接触させることにより、これらのガス濃度の検出を行う機能を有する。具体的には、センサ素子１２４が検知対象ガスに接触すると、各々のガス雰囲気のガス濃度に反応して検出電圧が立ち上がり始め、この検出電圧がＣＰＵ１６４の入力ポートＰ３に印加される。
【００３９】
ガスセンサ１２の出力応答特性は、センサ素子１２４自体の出力応答特性、およびガス暴露のタイミングによって決定されるものである。
【００４０】
図３は、図２のガス警報器１０における、通常動作モード時におけるイネーブル信号１６ｅの生成タイミング、すなわち、ガスの検出タイミングを説明するためのタイミングチャートである。
【００４１】
また、図４は、図２のガス警報器１０における、点検動作モード時におけるイネーブル信号１６ｅの生成タイミング、すなわち、ガスの検出タイミングを説明するためのタイミングチャートである。
【００４２】
加熱駆動手段１４は、エミッタが電源Ｖｃｃに接続され、コレクタがガスセンサ１２のヒータ１２２に接続されたｐｎｐ型トランジスタＱ１と、トランジスタＱ１のエミッタとベース間に接続された抵抗Ｒ１と、トランジスタＱ１のベースと動作モード制御手段１６のＣＰＵ１６４の出力ポートＰ４間に接続された抵抗Ｒ２とからなり、第１ガスモード加熱信号１６ａまたは第２ガスモード加熱信号１６ｂに基づいて、ヒータ１２２を作動するための加熱信号１４ａを生成する機能を有する。
【００４３】
トランジスタＱ１のベースにＣＰＵ１６４からの第１ガスモード加熱信号１６ａまたは第２ガスモード加熱信号１６ｂが与えられることにより、トランジスタＱ１は、第１ガスモード加熱信号１６ａまたは第２ガスモード加熱信号１６ｂに基づいて、ヒータ１２２を作動するための加熱信号１４ａを生成することができる。
【００４４】
第１ガスモード加熱信号１６ａは、図３および図４に示すように、ヒータ１２２を加熱するための加熱電圧ＶＨＬ（単位は［Ｖ］）で与えられる。同様に、第２ガスモード加熱信号１６ｂは、加熱電圧ＶＨＬより高い加熱電圧ＶＨＨ（単位は［Ｖ］）で与えられる。
【００４５】
加熱駆動手段１４は、具体的には、図３および図４に示すように、第１ガスモード加熱信号１６ａに応じて、ガスセンサ１２の温度を、７０乃至１００℃程度の低温域にＴ２（＝５〜２０秒）の期間だけ、ヒータ１２２を制御するための加熱信号１４ａを生成する。
【００４６】
同様に、第２ガスモード加熱信号１６ｂに応じて、ガスセンサ１２の温度を、３５０乃至４００℃程度の高温域にＴ１（＝３〜５秒）の期間だけ、ヒータ１２２を制御するための加熱信号１４ａを生成する。
【００４７】
動作モード制御手段１６は、ＣＰＵ１６４を中心にして構成されており、さらに、第１ガス警報濃度Ａ１に対応する第１ガス警報レベルＶ１を設定するための第１基準電圧生成部と、第２ガス警報濃度Ａ２に対応する第２ガス警報レベルＶ２を設定するための第２基準電圧生成部とを有する。
【００４８】
第１基準電圧生成部は、電源Ｖｃｃと接地間に直列接続された抵抗Ｒ７と、ＣＰＵ１６４の出力ポートＰ７からの制御信号で可変制御される電子ボリュームＶＲ１とから構成されている。第１ガス警報レベルＶ１は、この電子ボリュームＶＲ１を調節して得られるＶＲ１の抵抗値と抵抗Ｒ７の抵抗値との分圧比（すなわち、ＶＲ１／（ＶＲ１＋Ｒ７）によって決定され、ＣＰＵ１６４の入力ポートＰ１に出力される。
【００４９】
同様に、第２基準電圧生成部は、電源電圧Ｖｃｃと接地間に直列接続された抵抗Ｒ９と、ＣＰＵ１６４の出力ポートＰ７からの制御信号で可変制御される電子ボリュームＶＲ２と抵抗Ｒ９から構成されている。第２ガス警報レベルＶ２は、この電子ボリュームＶＲ２を調節して得られるＶＲ２の抵抗値と抵抗Ｒ９の抵抗値との分圧比（すなわち、ＶＲ２／（ＶＲ２＋Ｒ９）によって決定され、ＣＰＵ１６４の入力ポートＰ２に出力される。
【００５０】
動作モード制御手段１６は、前述の低温域で、ＣＯガス１１Ａのガス濃度である第１ガス濃度Ｃ１の検出期間Ｔ２中に、検出された第１ガス濃度Ｃ１（すなわち、ガス濃度信号１２ａ）が第１ガス警報濃度Ａ１に達した際に、ＣＯガス１１Ａが異常となった旨の第１警報を報知する機能を有する。
【００５１】
さらに、動作モード制御手段１６は、前述の高温域で、ＣＨ₄ガス１１Ｂのガス濃度である第２ガス濃度Ｃ２の検出期間Ｔ１中に、検出された第２ガス濃度Ｃ２（すなわち、ガス濃度信号１２ａ）が第２ガス警報濃度Ａ２に達した際に、ＣＨ₄ガスが異常となった旨の第２警報を報知する機能を有する。
【００５２】
動作モード制御手段１６に設けられたセンサ制御部１６２は、エミッタが電源Ｖｃｃに接続されかつコレクタが抵抗Ｒ４を介して負荷としてのセンサ素子１２４に接続されているｐｎｐ型トランジスタＱ２と、電源ＶｃｃとトランジスタＱ２のベース間に接続された抵抗Ｒ５と、トランジスタＱ２のベースとＣＰＵ１６４の出力ポートＰ５間に接続された抵抗Ｒ６と、センサ素子１２４にバイアス電流を与えるために電源Ｖｃｃとセンサ素子１２４間に接続された抵抗Ｒ３とから構成されている。
【００５３】
センサ制御部１６２は、通常動作モード時には、第１ガス濃度Ｃ１の検出期間Ｔ２中に第１ガス１１Ａに係る第１ガスモード加熱信号１６ａが印加されている間の所定のタイミング（すなわち、図３中の「白丸」で示されるＣＯガス検出ポイント）で、または第２ガスモード加熱信号１６ｂが印加されている間の所定のタイミング（すなわち、図３中の「黒丸」で示されるＣＨ₄ガス検出ポイント）で、ガスセンサ１２における第１ガス１１Ａまたは第２ガス１１Ｂに係るガス濃度信号１２ａの生成を命令するためのイネーブル信号１６ｅを生成する機能を有する。
【００５４】
また、センサ制御部１６２は、点検動作モード時には、図４に示すように、第１ガス濃度Ｃ１の検出期間Ｔ２中に第１ガス１１Ａに係る第１ガスモード加熱信号１６ａが印加されている間常に、または第２ガスモード加熱信号１６ｂが印加されている間常に、ガスセンサ１２における第１ガス１１Ａまたは第２ガス１１Ｂに係るガス濃度信号１２ａの生成を命令するためのイネーブル信号１６ｅを生成する機能を有する。
【００５５】
ＣＰＵ１６４は、出力ポートＰ５からイネーブル信号１６ｅを出力してトランジスタＱ２を制御することにより、センサ素子１２４からのガス濃度信号１２ａを入力端子Ｐ３から取り込んでいる。
【００５６】
警報手段１８は、ＣＰＵ１６４の出力ポートＰ６にベースが接続されたｎｐｎ型トランジスタＱ３と、トランジスタＱ３のコレクタ負荷としてコレクタと電源Ｖｃｃ間に接続されたブザー１８２（図中Ｂｚ）から構成されている。
【００５７】
ＣＰＵ１６４は、第１ガスモード警報信号１６ｃまたは第２ガスモード警報信号１６ｄを出力端子Ｐ６からトランジスタＱ３のベースに与えて、警報音１８ａの発生を促す制御を行う。
【００５８】
次に、ガス警報器１０の動作について説明する。ガス警報器１０の動作を要約すると、ガス警報器１０の設置場所への取り付け時、ガスセンサ１２の動作、すなわち、ガスセンサ１２が正常にガス検知を行うかどうか、を確認するため、点検用ガスをガスセンサ１２に吹き付ける点検作業を行う。
【００５９】
そこで、ガス警報器１０の電源を投入し、所定時間（たとえば、１分間）の初期遅延後、動作モード制御手段１６は、点検動作モード期間を所定時間（たとえば、３分間）設ける。この間に、点検用ガスの吹き付けによる点検を行う。点検動作モード中は、動作モード制御手段１６は、ガス濃度の検出期間中常にガスセンサ１２でガス濃度を検出し、検出された点検用ガスの濃度が警報濃度以上になると、警報手段１８のブザー１８２の鳴動を開始させ、所定時間経過後鳴動を強制的に停止させる。
【００６０】
その後、ガス警報器１０は、点検動作モード中に警報手段１８のブザー１８２の鳴動が一度でも発生すると、点検動作モード期間の終了を待たずに直ちに、動作モードを点検動作モードから通常動作モードに切り換え、以後通常動作モードで動作し、警報濃度以上のガス濃度が検出された際には、警報手段１８のブザー１８２を鳴動させ、警報を報知する。
【００６１】
次に、図５および図６のフローチャートを参照して、図１のガス警報器１０の動作を詳細に説明する。ガス警報器１０の動作は、動作モード制御手段１６のＣＰＵ１６４の処理に基づいて行われる。まず、図５のフローチャートにおいて、まず、ガス警報器１０を電源ＯＮし（ステップＳ１１）、次いで、回路の安定動作に達するまで動作の初期遅延時間（たとえば、６０秒）の間待機する（ステップＳ１２）。この間、ガスセンサ１２のクリーニングのため、ＣＰＵ１６４の出力ポートＰ４からのクリーニング用加熱信号により、トランジスタＱ１がＯＮになり、ヒータ１２２のヒートアップを行っている。
【００６２】
初期遅延が終了すると、次に、ＣＰＵ１６４は、内蔵の点検動作モード用タイマー（図２では図示していない）をスタートさせ（ステップＳ１３）、次いで、点検動作モード用タイマーのカウントにより点検動作モード期間としての１８０秒（３分）が経過したか否かを判定する（ステップＳ１４）。１８０秒（３分）経過していなければ、ＣＰＵ１６４は、点検動作モードを開始する（ステップＳ１５）。
【００６３】
この点検動作モードの開始により、ＣＰＵ１６４は、出力ポートＰ４から、第１ガスモード加熱信号１６ａおよび第２ガスモード加熱信号１６ｂをトランジスタＱ１のベースに印加する。それにより、トランジスタＱ１は、図４に示すような加熱信号１４ａを生成し、ガスセンサ１２のヒータ１２２を駆動する。
【００６４】
次いで、ＣＰＵ１６４は、第１ガス警報濃度Ａ１および第２ガス警報濃度Ａ２を、それぞれ、点検動作モード用第１ガス警報濃度Ａ１ｉをたとえば１５０ｐｐｍに設定し、点検動作モード用第２ガス警報濃度Ａ２ｉをたとえば３０００ｐｐｍに設定する（ステップＳ１６）。
【００６５】
この設定は次のようにして行われる。すなわち、ＣＰＵ１６４は、出力ポートＰ７から点検動作モード用のレベルの制御信号を電子ボリュームＶＲ１およびＶＲ２に出力することにより、第１基準電圧生成部および第２基準電圧生成部の第１ガス警報レベルＶ１および第２ガス警報レベルＶ２を、それぞれ、点検動作モード用第１ガス警報レベルＶ１ｉおよび点検動作モード用第２ガス警報レベルＶ２ｉに設定する。このように設定された点検動作モード用第１ガス警報レベルＶ１ｉおよび点検動作モード用第２ガス警報レベルＶ２ｉは、それぞれ、点検動作モード用第１ガス警報濃度Ａ１ｉ、たとえば１５０ｐｐｍ、および点検動作モード用第２ガス警報濃度Ａ２ｉ、たとえば３０００ｐｐｍ、に対応する基準電圧として、ＣＰＵ１６４の入力ポートＰ１およびＰ２に印加される。
【００６６】
次に、ＣＰＵ１６４は、ガスセンサ１２のセンサ素子１２４で検出されたガス濃度が、点検用ガスとしてＣＯガス１１Ａが吹き付けられた場合には１５０ｐｐｍ以上であるか否か、あるいは点検用ガスとしてＣＨ₄ガス１１Ｂが吹き付けられた場合には３０００ｐｐｍ以上であるか否かを判定する（ステップＳ１７）。この判定は、ＣＰＵ１６４が、図４に示すように、出力ポートＰ５からのイネーブル信号１６ｅによるセンサ制御部１６２の制御によりＴ１およびＴ２のガス濃度の検出期間中、常に、ガスセンサ１２のセンサ素子１２４の検出電圧（ガス濃度信号１２ａ）を入力ポートＰ３から取り込み、取り込んだ検出電圧が第１ガス警報レベルＶ１または第２ガス警報レベルＶ２以上であるか否かを判定することにより行われる。
【００６７】
次に、ステップＳ１７の答がＹＥＳであれば、ＣＰＵ１６４は、内蔵の警報用タイマー（図示しない）をスタートさせ（ステップＳ１８）、次いで、出力ポートＰ６から制御信号を出力してトランジスタＱ３をオンになるように制御してブザー１８２の鳴動を開始させることにより、点検用ガスがＣＯガス１１Ａの場合には、ＣＯガス１１Ａの濃度Ｃ１が第１ガス警報濃度Ａ１（＝１５０ｐｐｍ）以上の異常値になった旨の第１警報を報知し、点検用ガスがＣＨ₄ガス１１Ｂの場合には、ＣＨ₄ガス１１Ｂの濃度Ｃ２が第２ガス警報濃度Ａ２（＝３０００ｐｐｍ）以上の異常値になった旨の第２警報を報知する（ステップＳ１９）。
【００６８】
次に、ＣＰＵ１６４は、警報用タイマーのカウントが所定時間（たとえば、３秒）経過したか否かを判定する（ステップＳ２０）。３秒経過していなければ、ステップＳ１９に戻り、ブザー１８２の鳴動による警報を継続する。
【００６９】
３秒経過していれば、ＣＰＵ１６４は、警報を停止し（ステップＳ２１）、次いで警報用タイマーをリセットし（ステップＳ２２）、次いで、動作モードを点検動作モードから通常動作モードに切り換え、通常動作モードによる処理を行う（ステップＳ１０）。
【００７０】
一方、ステップＳ１４で１８０秒（３分）経過していれば、ＣＰＵ１６４は、点検動作モード用タイマーをリセット（ステップＳ２３）、次いで動作モードを点検動作モードから通常動作モードに切り換え、通常動作モードによる処理を行う（ステップＳ１０）。
【００７１】
次に、ステップＳ１０で行われる通常動作モード時の動作について、図６のフローチャートを参照して説明する。
【００７２】
動作モードが点検動作モードから通常動作モードに切り換えられると、まず、ＣＰＵ１６４は、第１ガス警報濃度Ａ１および第２ガス警報濃度Ａ２を、それぞれ、通常動作モード用第１ガス警報濃度Ａ１ｎおよび通常動作モード用第２ガス警報濃度Ａ２ｎに設定する。本実施形態では、点検動作モード用第１ガス警報濃度Ａ１ｉと通常動作モード用第１ガス警報濃度Ａ１ｎが同一に設定され、点検動作モード用第２ガス警報濃度Ａ２ｉと通常動作モード用第２ガス警報濃度Ａ２ｎも同一に設定されるので、通常動作モード用第１ガス警報濃度Ａ１ｎは１５０ｐｐｍに設定され、通常動作モード用第２ガス警報濃度Ａ２ｎは３０００ｐｐｍに設定する（ステップＳ１０１）。
【００７３】
この設定は、ＣＰＵ１６４の出力ポートＰ７から点検動作モード用のレベルと同一レベルの通常動作モード用制御信号を電子ボリュームＶＲ１およびＶＲ２に出力することにより行われる。
【００７４】
次に、ＣＰＵ１６４は、ガスセンサ１２のセンサ素子１２４で検出されたガス濃度が、ＣＯガス１１Ａの場合には１５０ｐｐｍ以上であるか否か、あるいはＣＨ₄ガス１１Ｂの場合には３０００ｐｐｍ以上であるか否かを判定する（ステップＳ１０２）。この判定は、ＣＰＵ１６４が、出力ポートＰ５からのイネーブル信号１６ｅによるセンサ制御部１６２の制御により決定される所定のタイミング（すなわち、図３に示すＣＯガス検知ポイントまたはＣＨ₄ガス検知ポイント）で、ガスセンサ１２のセンサ素子１２４の検出電圧（ガス濃度信号１２ａ）を入力ポートＰ３から取り込み、取り込んだ検出電圧が第１ガス警報レベルＶ１または第２ガス警報レベルＶ２以上であるか否かを判定することにより行われる。
【００７５】
次に、ステップＳ１０２の答がＹＥＳであれば、ＣＰＵ１６４は、出力ポートＰ６から第１ガスモード警報信号１６ｃまたは第２ガスモード警報信号１６ｄを出力してトランジスタＱ３をオンになるように制御してブザー１８２を鳴動させることにより、検出されたガスがＣＯガス１１Ａの場合には、ＣＯガス１１Ａの濃度Ｃ１が通常動作モード用第１ガス警報濃度ＡＩｎ（＝１５０ｐｐｍ）以上の異常値になった旨の第１警報を報知し、検出されたガスがＣＨ₄ガス１１Ｂの場合には、ＣＨ₄ガス１１Ｂの濃度Ｃ２が通常動作モード用第２ガス警報濃度Ａ２ｎ（＝３０００ｐｐｍ）以上の異常値になった旨の第２警報を報知する（ステップＳ１０３）。
【００７６】
以上説明したように、本発明の第１の実施形態によれば、通常動作モードと点検動作モードを設け、点検動作モード時にはガス濃度の検出期間中常にガスセンサ１２でガス濃度を検出し、検出された点検用ガスの濃度が警報濃度以上になると、警報手段１８のブザー１８２の鳴動を開始させ、所定時間経過後鳴動を強制的に停止させて、点検動作モード期間の終了を待たずに直ちに、動作モードを点検動作モードから通常動作モードに切り換えるので、従来より点検作業を短時間で行うことができる。
【００７７】
次に、本発明の第２の実施形態について説明する。上述の第１の実施形態では、点検動作モード用第１ガス警報濃度Ａ１ｉと通常動作モード用第１ガス警報濃度Ａ１ｎが同一に設定され、点検動作モード用第２ガス警報濃度Ａ２ｉと通常動作モード用第２ガス警報濃度Ａ２ｎも同一に設定されているが、第２の実施形態では、点検動作モード用第１ガス警報濃度Ａ１ｉは、通常動作モード用第１ガス警報濃度Ａ１ｎよりも低く設定され、点検動作モード用第２ガス警報濃度Ａ２ｉは、通常動作モード用第２ガス警報濃度Ａ１ｎよりも低く設定される。
【００７８】
以下、図７のフローチャートを参照して、本発明の第２の実施形態に係るガス警報器１０の動作を説明する。まず、ガス警報器１０を電源ＯＮし（ステップＳ１１）、次いで、回路の安定動作に達するまで動作の初期遅延時間（たとえば、６０秒）の間待機する（ステップＳ１２）。この間、ガスセンサ１２のクリーニングのため、ＣＰＵ１６４の出力ポートＰ４からのクリーニング用加熱信号により、トランジスタＱ１がＯＮになり、ヒータ１２２のヒートアップを行っている。
【００７９】
初期遅延が終了すると、次に、ＣＰＵ１６４は、内蔵の点検動作モード用タイマーをスタートさせ（ステップＳ１３）、次いで、点検動作モード用タイマーのカウントにより点検動作モード期間としての１８０秒（３分）が経過したか否かを判定する（ステップＳ１４）。１８０秒（３分）経過していなければ、ＣＰＵ１６４は、点検動作モードを開始する（ステップＳ１５）。
【００８０】
この点検動作モードの開始により、ＣＰＵ１６４は、出力ポートＰ４から、第１ガスモード加熱信号１６ａおよび第２ガスモード加熱信号１６ｂをトランジスタＱ１のベースに印加する。それにより、トランジスタＱ１は、図３に示すような加熱信号１４ａを生成し、ガスセンサ１２のヒータ１２２を駆動する。
【００８１】
次いで、ＣＰＵ１６４は、第１ガス警報濃度Ａ１および第２ガス警報濃度Ａ２を、それぞれ、通常動作モード用第１ガス警報濃度Ａ１ｎ（＝１５０ｐｐｍ）より低い点検動作モード用第１ガス警報濃度Ａ１ｉ、たとえば５０ｐｐｍ、および通常動作モード用第２ガス警報濃度Ａ２ｎ（＝３０００ｐｐｍ）より低い点検動作モード用第２ガス警報濃度Ａ２ｉ、たとえば５００ｐｐｍに設定する（ステップＳ１６）。
【００８２】
この設定は次のようにして行われる。すなわち、ＣＰＵ１６４は、出力ポートＰ７から点検動作モード用のレベルの制御信号を電子ボリュームＶＲ１およびＶＲ２に出力することにより、第１基準電圧生成部および第２基準電圧生成部の第１ガス警報レベルＶ１および第２ガス警報レベルＶ２を、それぞれ、点検動作モード用第１ガス警報レベルＶ１ｉおよび点検動作モード用第２ガス警報レベルＶ２ｉに設定する。このように設定された点検動作モード用第１ガス警報レベルＶ１ｉおよび点検動作モード用第２ガス警報レベルＶ２ｉは、それぞれ、点検動作モード用第１ガス警報濃度Ａ１ｉ、たとえば５０ｐｐｍ、および点検動作モード用第２ガス警報濃度Ａ２ｉ、たとえば５００ｐｐｍ、に対応する基準電圧として、ＣＰＵ１６４の入力ポートＰ１およびＰ２に印加される。
【００８３】
次に、ＣＰＵ１６４は、ガスセンサ１２のセンサ素子１２４で検出されたガス濃度が、点検用ガスとしてＣＯガス１１Ａが吹き付けられた場合には５０ｐｐｍ以上であるか否か、あるいは点検用ガスとしてＣＨ₄ガス１１Ｂが吹き付けられた場合には５００ｐｐｍ以上であるか否かを判定する（ステップＳ１７）。この判定は、ＣＰＵ１６４が、図４に示すように、出力ポートＰ５からのイネーブル信号１６ｅによるセンサ制御部１６２の制御によりＴ１およびＴ２のガス濃度の検出期間中、常に、ガスセンサ１２のセンサ素子１２４の検出電圧（ガス濃度信号１２ａ）を入力ポートＰ３から取り込み、取り込んだ検出電圧が点検動作モード用第１ガス警報レベルＶ１ｉまたは点検動作モード用第２ガス警報レベルＶ２ｉ以上であるか否かを判定することにより行われる。
【００８４】
次に、ステップＳ１７の答がＹＥＳであれば、ＣＰＵ１６４は、内蔵の警報用タイマー（図示しない）をスタートさせ（ステップＳ１８）、次いで、出力ポートＰ６から制御信号を出力してトランジスタＱ３をオンになるように制御してブザー１８２を鳴動させることにより、点検用ガスがＣＯガス１１Ａの場合には、ＣＯガス１１Ａの濃度Ｃ１が点検モード用第１ガス警報濃度Ａ１ｉ（＝５０ｐｐｍ）以上の異常値になった旨の第１警報を報知し、点検用ガスがＣＨ₄ガス１１Ｂの場合には、ＣＨ₄ガス１１Ｂの濃度Ｃ２が点検モード用第２ガス警報濃度Ａ２ｉ（＝５００ｐｐｍ）以上の異常値になった旨の第２警報を報知する（ステップＳ１９）。
【００８５】
次に、ＣＰＵ１６４は、警報用タイマーのカウントが所定時間（たとえば、３秒）経過したか否かを判定する（ステップＳ２０）。３秒経過していなければ、ステップＳ１９に戻り、ブザー１８２の鳴動による警報を継続する。
【００８６】
３秒経過していれば、ＣＰＵ１６４は、警報を停止し（ステップＳ２１）、次いで警報用タイマーをリセットし（ステップＳ２２）、次いで、動作モードを点検動作モードから通常動作モードに切り換え、通常動作モード（図６参照）による処理を行う（ステップＳ１０）。
【００８７】
一方、ステップＳ１４で１８０秒（３分）経過していれば、ＣＰＵ１６４は、点検動作モード用タイマーをリセット（ステップＳ２３）、次いで動作モードを点検動作モードから通常動作モードに切り換え、通常動作モードによる処理（図６参照）を行う（ステップＳ１０）。
【００８８】
次に、この第２の実施形態においてステップＳ１０で行われる通常動作モード時の動作について、図６のフローチャートを参照して説明する。
【００８９】
動作モードが点検動作モードから通常動作モードに切り換えられると、まず、ＣＰＵ１６４は、第１ガス警報濃度Ａ１および第２ガス警報濃度Ａ２を、それぞれ、点検動作モード用第１ガス警報濃度Ａ１ｉ（＝５０ｐｐｍ）および点検動作モード用第２ガス警報濃度Ａ２ｉ（＝５００ｐｐｍ）から、通常動作モード用第１ガス警報濃度Ａ１ｎ、たとえば１５０ｐｐｍ、および通常動作モード用第２ガス警報濃度Ａ２ｎ、たとえば３０００ｐｐｍに設定変更する（ステップＳ１０１）。
【００９０】
この設定は次のようにして行われる。すなわち、ＣＰＵ１６４は、出力ポートＰ７から通常動作モード用のレベルの制御信号を電子ボリュームＶＲ１およびＶＲ２に出力することにより、第１基準電圧生成部および第２基準電圧生成部の第１ガス警報レベルＶ１および第２ガス警報レベルＶ２を、それぞれ、通常動作モード用第１ガス警報レベルＶ１ｎおよび通常動作モード用第２ガス警報レベルＶ２ｎに設定する。このように設定された通常動作モード用第１ガス警報レベルＶ１ｎおよび通常動作モード用第２ガス警報レベルＶ２ｎは、それぞれ、通常動作モード用第１ガス警報濃度Ａ１ｎ、たとえば１５０ｐｐｍ、および通常動作モード用第２ガス警報濃度Ａ２ｎ、たとえば３０００ｐｐｍ、に対応する基準電圧として、ＣＰＵ１６４の入力ポートＰ１およびＰ２に印加される。
【００９１】
次に、ＣＰＵ１６４は、ガスセンサ１２のセンサ素子１２４で検出されたガス濃度が、ＣＯガス１１Ａの場合には１５０ｐｐｍ以上であるか否か、あるいはＣＨ₄ガス１１Ｂの場合には３０００ｐｐｍ以上であるか否かを判定する（ステップＳ１０２）。この判定は、ＣＰＵ１６４が、出力ポートＰ５からのイネーブル信号１６ｅによるセンサ制御部１６２の制御により決定される所定のタイミング（すなわち、図３に示すＣＯガス検知ポイントまたはＣＨ₄ガス検知ポイント）で、ガスセンサ１２のセンサ素子１２４の検出電圧を入力ポートＰ３から取り込み、取り込んだ検出電圧（ガス濃度信号１２ａ）が通常動作モード用第１ガス警報レベルＶ１ｎまたは通常動作モード用第２ガス警報レベルＶ２ｎ以上であるか否かを判定することにより行われる。
【００９２】
次に、ステップＳ１０２の答がＹＥＳであれば、ＣＰＵ１６４は、出力ポートＰ６から第１ガスモード警報信号１６ｃまたは第２ガスモード警報信号１６ｄを出力してトランジスタＱ３をオンになるように制御してブザー１８２を鳴動させることにより、検出されたガスがＣＯガス１１Ａの場合には、ＣＯガス１１Ａの濃度Ｃ１が通常動作モード用第１ガス警報濃度ＡＩｎ（＝１５０ｐｐｍ）以上の異常値になった旨の第１警報を報知し、検出されたガスがＣＨ₄ガス１１Ｂの場合には、ＣＨ₄ガス１１Ｂの濃度Ｃ２が通常動作モード用第２ガス警報濃度Ａ２ｎ（＝３０００ｐｐｍ）以上の異常値になった旨の第２警報を報知する（ステップＳ１０３）。
【００９３】
このように、本発明の第２の実施形態によれば、点検動作モード時には、検出された点検ガスの濃度が、通常動作モード用警報濃度より低く設定された点検動作モード用警報濃度以上になった際に警報を報知するので、低濃度のガスで短時間に点検でき、なおかつ高濃度ガスからセンサを回避させることが可能となる。
【００９４】
以上の通り、本発明の実施の形態について説明したが、本発明はこれに限らず、種々の変形、応用が可能である。
【００９５】
たとえば、上述の第１の実施形態においては、第１および第２基準電圧生成部は、抵抗Ｒ７，Ｒ９と電子ボリュームＶＲ１，ＶＲ２で構成されているが、他の構成とすることができる。
【００９６】
また、点検動作モード時の警報時間（たとえば、３秒）は一例であって、他の時間としても良く、好適には３〜５秒とすることができる。
【００９７】
【発明の効果】
請求項１記載の発明によれば、従来より点検作業を短時間に行うことができる。
【００９８】
請求項２記載の発明によれば、従来より点検作業を短時間に行うことができる。
【００９９】
請求項３記載の発明によれば、低濃度のガスで従来より点検作業を短時間に行うことができ、また警報を報知された時点で点検用ガスをガスセンサから遠ざけることにより高濃度ガスにガスセンサがさらされないようにして、従来のような点検時の警報手段の鳴動持続や再鳴動を回避することが可能となる。
【０１００】
請求項４記載の発明によれば、従来より点検作業を短時間に行うことができる。
【０１０１】
請求項５記載の発明によれば、１つのガスセンサで複数種類のガスに対するガス濃度を検出することができる。
【０１０２】
請求項６記載の発明によれば、ガスセンサ１２のヒータ１２２を２種類のガスのそれぞれの適正温度まで加熱することができる。
【０１０３】
請求項７記載の発明によれば、所定のタイミングでガス濃度信号を生成して、検出ミスが発生しないようにすることができ、また短時間で点検を確認することができる。
【０１０４】
請求項８記載の発明によれば、従来より点検作業を短時間に行うことができる。
【０１０５】
請求項９記載の発明によれば、低濃度のガスで従来より点検作業を短時間に行うことができ、また警報を報知された時点で点検用ガスをガスセンサから遠ざけることにより高濃度ガスにガスセンサがさらされないようにして、従来のような点検時の警報手段の鳴動持続や再鳴動を回避することが可能となる。
【０１０６】
請求項１０記載の発明によれば、ガスセンサのヒータを２種類のガスのそれぞれの適正温度まで加熱するように制御することができる。
【０１０７】
請求項１１記載の発明によれば、所定のタイミングでガス濃度信号を生成して、検出ミスが発生しないようにすることができ、また短時間で点検を確認することができる。
【０１０８】
請求項１２記載の発明によれば、ガス警報器を設置場所への取り付け時に、通常動作を行わせる前に短時間で点検を行うことができる。
【０１０９】
請求項１３記載の発明によれば、ガス警報器を設置場所への取り付け時に、通常動作を行わせる前に、低濃度のガスで点検を行うことができると共に、点検時間を大幅に短縮することができる。
【図面の簡単な説明】
【図１】本発明に係るガス警報器の機能ブロック図である。
【図２】本発明に係るガス警報器の第１の実施形態を示す回路図である。
【図３】図２のガス警報器における通常動作モード時のガスの検出タイミングを説明するためのタイミングチャートである。
【図４】図２のガス警報器における点検動作モード時のガスの検出タイミングを説明するためのタイミングチャートである。
【図５】図２のガス警報器の動作を説明するフローチャートである。
【図６】図２のガス警報器の動作を説明するフローチャートである。
【図７】本発明に係るガス警報器の第２の実施形態における動作を説明するフローチャートである。
【符号の説明】
１０ガス警報器
１２ガスセンサ
１４加熱駆動手段
１６動作モード制御手段
１８警報手段
１２２ヒータ
１２４センサ素子
１６２センサ制御部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas alarm device, and more particularly to a gas alarm device having a normal operation mode and an inspection operation mode.
[0002]
[Prior art]
Usually, as a sensor used for a gas alarm, a contact combustion type or semiconductor type gas sensor is common. A catalytic combustion type gas sensor is usually a gas sensor in which a thin platinum wire of 20 to 50 μm is formed in a coil shape, a catalyst is applied on the coil, dried and fired.
[0003]
The gas detection by this gas sensor utilizes the principle that, when city gas or LP gas is present, the resistance value of the platinum coil increases due to the reaction heat of methane, isobutane, hydrogen and catalyst contained therein. Similar to the catalytic combustion type gas sensor, the semiconductor type gas sensor applies a catalyst on the coil, performs drying and firing, and forms a gas sensor. When gas comes into contact with the semiconductor surface of a semiconductor gas sensor, electrons are transferred between the semiconductor and adsorbed molecules, and the electrical conductivity changes. Therefore, the gas is detected by detecting this change in electrical conductivity. can do.
[0004]
[Problems to be solved by the invention]
In a combined alarm device that combines detection of city gas or LP gas, detection of incomplete combustion gas, and fire detection, when installing it at the user's home, in order to check the sensor characteristics, Check using carbon oxide gas. In the case of the current alarm device, for example, there is a problem that it takes a long time for the inspection work because it is in the inspection mode for 10 minutes after the power is turned on.
[0005]
Also, if the sensor reacts to a gas above a certain set point during the inspection mode, the delay will be ignored and it will sound immediately. At that time, if the gas is excessively blown to the sensor, there is a problem that these gases are adsorbed to the activated carbon inside the sensor and do not stop ringing even after the inspection is completed. Moreover, even if the sound stops, there is a risk that the gas adsorbed on the activated carbon will gradually be released after the operation is completed and will be sounded again.
[0006]
Therefore, in view of the conventional problems in the above-described inspection operation mode, the present invention provides a gas alarm device capable of shortening the inspection work time and reducing the excessive influence due to the inspection gas. It is aimed.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the invention according to claim 1 is shown in the basic configuration diagram of FIG. The temperature of the gas sensor is alternately changed periodically between the low temperature range and the high temperature range, and in the detection period of the gas concentration in either the low temperature range or the high temperature range, When the gas concentration detected by the gas sensor 12 is equal to or higher than a predetermined alarm concentration, an operation for switching and controlling the normal operation mode and the inspection operation mode in the gas alarm device that notifies the alarm that the gas concentration has become abnormal. The mode control means 16 is in the gas concentration detection period in the normal operation mode. One detection point of When the gas concentration is detected by the gas sensor 12 and the detected gas concentration is equal to or higher than the alarm concentration, an alarm is given to the effect that the gas concentration has become abnormal. period From the beginning to the end An operation mode control means 16 is provided which always detects a gas concentration with the gas sensor 12 and notifies an alarm that the gas concentration has become abnormal when the detected gas concentration is equal to or higher than the alarm concentration. It exists in the gas alarm device.
[0008]
According to invention of Claim 1, The temperature of the gas sensor is alternately changed periodically between the low temperature range and the high temperature range, and in the detection period of the gas concentration in either the low temperature range or the high temperature range, When the gas concentration detected by the gas sensor 12 is equal to or higher than a predetermined alarm concentration, an operation for switching and controlling the normal operation mode and the inspection operation mode in the gas alarm device that notifies the alarm that the gas concentration has become abnormal. The mode control means 16 is in the gas concentration detection period in the normal operation mode. One detection point of When the gas concentration is detected by the gas sensor 12 and the detected gas concentration is equal to or higher than the alarm concentration, an alarm that the gas concentration has become abnormal is notified, and in the inspection operation mode, the gas concentration detection period From the beginning to the end Since the gas concentration is always detected by the gas sensor 12, and when the detected gas concentration is equal to or higher than the alarm concentration, the operation mode control means 16 for notifying that the gas concentration has become abnormal is provided. The inspection work can be performed in a shorter time.
[0009]
In order to solve the above-mentioned problem, the invention according to claim 2 is characterized in that the operation mode control means 16 has a gas concentration detection period in the inspection operation mode. From the beginning to the end The gas sensor 12 always detects the gas concentration, and when the detected gas concentration exceeds the alarm concentration, the alarm that the gas concentration is abnormal is started, and the alarm is forcibly stopped after a predetermined time. It exists in the gas alarm device of Claim 1 characterized by the above-mentioned.
[0010]
According to the second aspect of the present invention, the operation mode control means 16 is configured to detect the gas concentration detection period in the inspection operation mode. From the beginning to the end The gas concentration is always detected by the gas sensor 12, and when the detected gas concentration is equal to or higher than the alarm concentration, an alarm that the gas concentration is abnormal is started, and the alarm is forcibly stopped after a predetermined time. Therefore, inspection work can be performed in a shorter time than before.
[0011]
The invention according to claim 3, which has been made to solve the above problems, The temperature of the gas sensor is alternately changed periodically between the low temperature range and the high temperature range, and in the detection period of the gas concentration in either the low temperature range or the high temperature range, When the gas concentration detected by the gas sensor 12 is equal to or higher than a predetermined alarm concentration, an operation for switching and controlling the normal operation mode and the inspection operation mode in the gas alarm device that notifies the alarm that the gas concentration has become abnormal. The mode control means 16 is in the gas concentration detection period in the normal operation mode. One detection point of When the gas concentration is detected by the gas sensor and the detected gas concentration is equal to or higher than the alarm concentration for the normal operation mode, an alarm is given to the effect that the gas concentration has become abnormal. Concentration detection period From the beginning to the end The gas sensor 12 always detects the gas concentration, and when the detected gas concentration exceeds the alarm concentration for inspection mode set lower than the alarm concentration for normal operation mode, an alarm that the gas concentration has become abnormal The gas alarm device is provided with the operation mode control means 16 for informing the above.
[0012]
According to invention of Claim 3, The temperature of the gas sensor is alternately changed periodically between the low temperature range and the high temperature range, and in the detection period of the gas concentration in either the low temperature range or the high temperature range, When the gas concentration detected by the gas sensor 12 is equal to or higher than a predetermined alarm concentration, an operation for switching and controlling the normal operation mode and the inspection operation mode in the gas alarm device that notifies the alarm that the gas concentration has become abnormal. The mode control means 16 is in the gas concentration detection period in the normal operation mode. One detection point of When the gas concentration is detected by the gas sensor and the detected gas concentration is equal to or higher than the alarm concentration for normal operation mode, an alarm that the gas concentration has become abnormal is reported, and in the inspection operation mode, the gas concentration is Detection period From the beginning to the end The gas concentration is always detected by the gas sensor 12, and when the detected gas concentration is equal to or higher than the alarm concentration for the inspection mode set lower than the alarm concentration for the normal operation mode, an alarm that the gas concentration has become abnormal is issued. Since the operation mode control means 16 for notifying is provided, the inspection work can be performed in a shorter time than before with a low concentration gas, and when the alarm is notified, the inspection gas is kept away from the gas sensor to increase the concentration. By preventing the gas sensor from being exposed to the gas, it is possible to avoid the continuous sounding and re-sounding of the alarm means at the time of inspection as in the prior art.
[0013]
According to a fourth aspect of the present invention, the operation mode control means 16 is configured to detect a gas concentration detection period in the inspection operation mode. From the beginning to the end The gas sensor 12 always detects the gas concentration, and when the detected gas concentration exceeds the alarm concentration for inspection mode set lower than the alarm concentration for normal operation mode, an alarm that the gas concentration has become abnormal The alarm is forcibly stopped after a predetermined time has elapsed Claim 3 Located in gas alarm.
[0014]
According to the fourth aspect of the present invention, the operation mode control means 16 is configured to detect the gas concentration detection period in the inspection operation mode. From the beginning to the end The gas concentration is always detected by the gas sensor 12, and when the detected gas concentration is equal to or higher than the alarm concentration for the inspection mode set lower than the alarm concentration for the normal operation mode, an alarm that the gas concentration has become abnormal is issued. Since the alarm is forcibly stopped after a predetermined time has elapsed, the inspection work can be performed in a shorter time than before.
[0015]
In order to solve the above-mentioned problem, the invention according to claim 5 is that the gas sensor 12 detects a gas concentration for two kinds of gases 11A and 11B and generates a gas concentration signal 12a, and the sensor The gas alarm device according to claim 1, further comprising a heater 122 that heats the element 124.
[0016]
According to the fifth aspect of the invention, the gas sensor 12 includes the sensor element 124 that detects the gas concentrations of the two types of gases 11A and 11B and generates the gas concentration signal 12a, and the heater 122 that heats the sensor element 124. Therefore, it is possible to detect gas concentrations for a plurality of types of gases with one gas sensor.
[0017]
The invention according to claim 6 made to solve the above-mentioned problem is a first for heating the sensor element 124 corresponding to each of the two kinds of gases 11A and 11B during the detection period of the gas concentration. The operation mode control means 16 for generating the gas mode heating signal 16a and the second gas mode heating signal 16b, and the heater 122 is operated based on the first gas mode heating signal 16a or the second gas mode heating signal 16b. 6. A gas alarm device according to claim 5, further comprising a heating driving means for generating a heating signal for generating the heating signal.
[0018]
According to the sixth aspect of the present invention, the first gas mode heating signal 16a and the second gas mode for heating the sensor element 124 corresponding to each of the two types of gases 11A and 11B during the gas concentration detection period. The operation mode control means 16 for generating the heating signal 16b and the heating driving means 14 for generating the heating signal 14a for operating the heater 122 based on the first gas mode heating signal 16a or the second gas mode heating signal 16b. Therefore, the heater 122 of the gas sensor 12 can be heated to the appropriate temperature of each of the two types of gases.
[0019]
In order to solve the above-mentioned problem, the invention according to claim 7 is characterized in that the operation mode control means 16 is in the normal operation mode while the first gas mode heating signal 16a is applied or in the second gas mode. While the heating signal 16b is applied One detection point of Then, an enable signal 16e for commanding generation of the gas concentration signal 12a in the gas sensor 12 is generated, and during the inspection operation mode, the second gas is applied while the first gas mode heating signal 16a is being applied. While mode heating signal 16b is applied From the beginning to the end 6. The gas alarm device according to claim 5, further comprising a sensor control unit 162 that generates an enable signal 16e for instructing generation of the gas concentration signal 12a in the gas sensor 12.
[0020]
According to the seventh aspect of the present invention, the operation mode control means 16 is in the normal operation mode while the first gas mode heating signal 16a is being applied or while the second gas mode heating signal 16b is being applied. One detection point of Thus, the enable signal 16e for instructing the generation of the gas concentration signal 12a in the gas sensor 12 is generated, and during the inspection operation mode, the first gas mode heating signal 16a is applied and the second gas mode heating signal 16b. While is applied From the beginning to the end Since the sensor control unit 162 that always generates the enable signal 16e for instructing the generation of the gas concentration signal 12a in the gas sensor 12 is provided, the gas concentration signal is generated at a predetermined timing so that no detection error occurs. In addition, the inspection can be confirmed in a short time.
[0021]
The invention according to claim 8, which has been made to solve the above problem, periodically changes the temperature of the gas sensor 12 between a low temperature region and a high temperature region, and changes the first gas concentration of the first gas 11 </ b> A in the low temperature region. The second gas concentration of the second gas 11B is detected at a higher temperature range, and the first gas concentration is abnormal when the first gas concentration is equal to or higher than the first gas alarm concentration. In the gas alarm device for notifying the second alarm that the second gas concentration becomes abnormal when the second gas concentration becomes equal to or higher than the second gas alarm concentration, the operation mode control is performed. The means 16 is in the first gas concentration detection period in the normal operation mode. One detection point of When the first gas concentration is detected by the gas sensor 12 and the detected first gas concentration is equal to or higher than the first gas alarm concentration, a first alarm indicating that the first gas concentration has become abnormal is notified. And during the second gas concentration detection period One detection point of When the second gas concentration is detected by the gas sensor 12 and the detected second gas concentration is equal to or higher than the second gas alarm concentration, a second alarm indicating that the second gas concentration has become abnormal is notified. At the same time, in the inspection operation mode, the detection period of the first gas concentration From the beginning to the end The gas sensor 12 always detects the first gas concentration, and when the detected first gas concentration is equal to or higher than the first gas alarm concentration, the first alarm is started to indicate that the first gas concentration is abnormal. The first alarm is forcibly stopped after a predetermined time, and the second gas concentration detection period From the beginning to the end The gas sensor 12 always detects the second gas concentration, and when the detected second gas concentration is equal to or higher than the second gas alarm concentration, a second alarm is started to indicate that the second gas concentration has become abnormal. The gas alarm device according to any one of claims 5 to 7, wherein the second alarm is forcibly stopped after a predetermined time has elapsed.
[0022]
According to the eighth aspect of the present invention, the temperature of the gas sensor 12 is periodically and alternately changed between the low temperature range and the high temperature range, the first gas concentration of the first gas 11A is detected in the low temperature range, and the first in the high temperature range. The second gas concentration of the two gases 11B is detected, and when the first gas concentration is equal to or higher than the first gas alarm concentration, a first alarm is given to the effect that the first gas concentration has become abnormal, In the gas alarm device for notifying the second alarm that the second gas concentration has become abnormal when the gas concentration becomes equal to or higher than the second gas alarm concentration, the operation mode control means 16 During the detection period of one gas concentration One detection point of The gas sensor 12 detects the first gas concentration, and when the detected first gas concentration is equal to or higher than the first gas alarm concentration, the first alarm is notified that the first gas concentration is abnormal, And during the second gas concentration detection period One detection point of When the second gas concentration is detected by the gas sensor 12 and the detected second gas concentration is equal to or higher than the second gas alarm concentration, a second alarm that the second gas concentration has become abnormal is notified. In the inspection operation mode, the detection period of the first gas concentration From the beginning to the end The gas sensor 12 always detects the first gas concentration, and when the detected first gas concentration is equal to or higher than the first gas alarm concentration, the first alarm is started to indicate that the first gas concentration is abnormal, The first alarm is forcibly stopped after a predetermined time, and the second gas concentration detection period From the beginning to the end The gas sensor 12 always detects the second gas concentration, and when the detected second gas concentration is equal to or higher than the second gas alarm concentration, a second alarm is started to indicate that the second gas concentration is abnormal, Since the second alarm is forcibly stopped after a predetermined time has elapsed, the inspection work can be performed in a shorter time than before.
[0023]
The invention according to claim 9, which has been made to solve the above problem, periodically changes the temperature of the gas sensor 12 between a low temperature region and a high temperature region, and changes the first gas concentration of the first gas 11 </ b> A in the low temperature region. The second gas concentration of the second gas 11B is detected at a higher temperature range, and the first gas concentration is abnormal when the first gas concentration is equal to or higher than the first gas alarm concentration. In the gas alarm device for notifying the second alarm that the second gas concentration becomes abnormal when the second gas concentration becomes equal to or higher than the second gas alarm concentration, the operation mode control is performed. The means 16 is in the first gas concentration detection period in the normal operation mode. One detection point of When the gas sensor 12 detects the first gas concentration and the detected first gas concentration is equal to or higher than the first gas alarm concentration for normal operation mode, the first gas concentration is abnormal. An alarm is issued and the second gas concentration detection period One detection point of When the second gas concentration is detected by the gas sensor 12 and the detected second gas concentration is equal to or higher than the second gas alarm concentration for normal operation mode, a second indication that the second gas concentration has become abnormal. While informing the alarm, in the inspection operation mode, the detection period of the first gas concentration From the beginning to the end When the first gas concentration is always detected by the gas sensor 12 and the detected first gas concentration becomes equal to or higher than the first gas alarm concentration for inspection operation mode set lower than the first gas alarm concentration for normal operation mode. The first alarm that the first gas concentration has become abnormal is started, the first alarm is forcibly stopped after a predetermined time, and the second gas concentration detection period From the beginning to the end When the second gas concentration is always detected by the gas sensor 12 and the detected second gas concentration becomes equal to or higher than the second gas alarm concentration for inspection operation mode set lower than the second gas alarm concentration for normal operation mode. The second alarm that the second gas concentration becomes abnormal is started, and the second alarm is forcibly stopped after a predetermined time has elapsed. Located in gas alarm.
[0024]
According to the ninth aspect of the present invention, the temperature of the gas sensor 12 is periodically and alternately changed between the low temperature region and the high temperature region, the first gas concentration of the first gas 11A is detected in the low temperature region, and the first in the high temperature region. The second gas concentration of the two gases 11B is detected, and when the first gas concentration is equal to or higher than the first gas alarm concentration, a first alarm is given to the effect that the first gas concentration has become abnormal, In the gas alarm device that notifies the second alarm that the second gas concentration has become abnormal when the gas concentration becomes equal to or higher than the second gas alarm concentration, the operation mode control means 16 During the first gas concentration detection period One detection point of When the first gas concentration is detected by the gas sensor 12 and the detected first gas concentration is equal to or higher than the first gas alarm concentration for normal operation mode, a first alarm that the first gas concentration becomes abnormal is detected. And during the second gas concentration detection period One detection point of When the second gas concentration is detected by the gas sensor 12 and the detected second gas concentration is equal to or higher than the second gas alarm concentration for normal operation mode, a second alarm that the second gas concentration becomes abnormal is detected. And in the inspection operation mode, the detection period of the first gas concentration From the beginning to the end When the first gas concentration is always detected by the gas sensor 12 and the detected first gas concentration is equal to or higher than the first gas alarm concentration for inspection operation mode set lower than the first gas alarm concentration for normal operation mode, The first alarm that the first gas concentration is abnormal is started, the first alarm is forcibly stopped after a predetermined time, and the second gas concentration detection period From the beginning to the end When the second gas concentration is always detected by the gas sensor 12 and the detected second gas concentration becomes equal to or higher than the second gas alarm concentration for inspection operation mode set lower than the second gas alarm concentration for normal operation mode, Since the second alarm that the second gas concentration has become abnormal is started and the second alarm is forcibly stopped after a predetermined time has elapsed, it is possible to perform inspection work with a low concentration of gas in a shorter time than before. In addition, by keeping the gas for inspection away from the gas sensor at the time when the alarm is notified, the gas sensor is not exposed to the high-concentration gas, so that it is possible to avoid the continuation of the alarm means and the re-sound of the alarm means during the conventional inspection. It becomes possible.
[0025]
In order to solve the above-mentioned problem, the invention according to claim 10 is characterized in that the operation mode controller 16 heats the sensor element 124 to the low temperature region during the detection period of the first gas concentration. A first gas mode heating signal 16a is generated, and the second gas mode heating signal 16b for heating the sensor element 124 to the high temperature range is generated during the detection period of the second gas concentration. It exists in the gas alarm device of Claim 8 or 9 characterized by the above-mentioned.
[0026]
According to the tenth aspect of the present invention, the operation mode control means 16 generates the first gas mode heating signal 16a for heating the sensor element 124 to a low temperature region during the detection period of the first gas concentration, and the second Since the second gas mode heating signal 16b for heating the sensor element 124 to the high temperature range is generated during the gas concentration detection period, the heater of the gas sensor is set to the appropriate temperature of each of the two types of gases. It can be controlled to heat.
[0027]
According to an eleventh aspect of the present invention, in order to solve the above problem, the sensor control unit 162 is configured so that the first gas related to the first gas 11A is detected during the detection period of the first gas concentration in the normal operation mode. While mode heating signal 16a is applied One detection point of Or while the second gas mode heating signal 16b relating to the second gas 11B is applied during the detection period of the second gas concentration One detection point of Thus, the gas sensor 12 generates the enable signal 16e for commanding the generation of the gas concentration signal 12a related to the first gas 11A or the second gas 11B, and at the time of the inspection operation mode, the first gas concentration While the first gas mode heating signal 16a related to the first gas 11A is being applied during the detection period From the beginning to the end While the second gas mode heating signal 16b relating to the second gas 11B is being applied constantly or during the detection period of the second gas concentration From the beginning to the end The configuration is such that the enable signal 16e for instructing the generation of the gas concentration signal 12a related to the first gas 11A or the second gas 11B in the gas sensor 12 is always generated. It exists in the gas alarm of any one of 8 to 10.
[0028]
According to the eleventh aspect, in the normal operation mode, the sensor control unit 162 applies the first gas mode heating signal 16a related to the first gas 11A during the first gas concentration detection period. One detection point of Or while the second gas mode heating signal 16b related to the second gas 11B is applied during the detection period of the second gas concentration One detection point of Thus, the enable signal 16e for instructing the generation of the gas concentration signal 12a related to the first gas 11A or the second gas 11B in the gas sensor 12 is generated, and in the inspection operation mode, the first signal concentration is detected during the first gas concentration detection period. While the first gas mode heating signal 16a relating to one gas 11A is being applied From the beginning to the end While the second gas mode heating signal 16b related to the second gas 11B is being applied constantly or during the detection period of the second gas concentration From the beginning to the end Since the enable signal 16e for instructing the generation of the gas concentration signal 12a related to the first gas 11A or the second gas 11B in the gas sensor 12 is always generated, the gas concentration signal is generated at a predetermined timing. Thus, a detection error can be prevented from occurring, and the inspection can be confirmed in a short time.
[0029]
According to a twelfth aspect of the present invention, the operation mode control means 16 operates the gas alarm device 10 in the inspection operation mode for a predetermined time when the power is turned on, and after the predetermined time has elapsed, the operation mode control means 16 operates. The gas alarm device according to any one of claims 1 to 11, wherein the gas alarm device 10 is operated by switching from the inspection operation mode to the normal operation mode.
[0030]
According to the twelfth aspect of the present invention, the operation mode control means 16 operates the gas alarm device 10 in the inspection operation mode for a predetermined time when the power is turned on, and after the predetermined time has elapsed, the operation mode control means 16 Since the operation is switched to the operation mode, the inspection can be performed in a short time before the normal operation is performed when the gas alarm is attached to the installation place.
[0031]
According to a thirteenth aspect of the present invention, the operation mode control means 16 operates the gas alarm device 10 in the inspection operation mode when the power is turned on, and the normal operation after the alarm stop in the inspection operation mode. 3. The gas alarm device according to claim 1, wherein the gas alarm device is operated by switching to a mode.
[0032]
According to the invention of claim 13, the operation mode control means 16 operates the gas alarm device 10 in the inspection operation mode when the power is turned on, and switches to the normal operation mode after the alarm stop in the inspection operation mode. When the gas alarm is attached to the installation location, it is possible to perform inspection with a low-concentration gas before performing normal operation, and to greatly reduce the inspection time.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described.
[0034]
FIG. 2 is a circuit diagram showing a first embodiment of the gas alarm device according to the present invention. In the following description, carbon monoxide (CO) gas as the first gas 11A, and methane (CH contained in the city gas as the second gas 11B) _Four ) As the gas alarm device 10 for detecting the gas of the gas, in particular, the temperature of the gas sensor 12 is periodically changed alternately between a low temperature region and a high temperature region, and the first gas 11A (that is, CO gas) is first changed in the low temperature region. The gas concentration C1 is detected, and the second gas 11B (that is, CH _Four Gas) is detected, and when the first gas concentration C1 is equal to or higher than a predetermined first gas alarm concentration A1, a first alarm indicating that the first gas concentration C1 has become abnormal is issued. As an embodiment, the gas detection device 10 that notifies and notifies the second alarm that the second gas concentration C2 becomes abnormal when the second gas concentration C2 becomes equal to or higher than a predetermined second gas alarm concentration A2. This will be described with reference to FIG.
[0035]
The gas alarm device 10 in FIG. 2 includes a gas sensor 12, a heating drive unit 14, an operation mode control unit 16, and an alarm unit 18.
[0036]
Specifically, in the gas alarm device 10 of the present embodiment, the temperature of the gas sensor 12 is a low temperature range in which about 70 to 100 ° C. continues for about 5 to 20 seconds, and about 350 to 400 ° C. continues for about 3 to 5 seconds. The first gas concentration C1 (unit: [ppm]) of the first gas (CO gas) 11A is detected in such a low temperature range, and alternately in the high temperature range. Second gas 11B (CH _Four Gas) when the second gas concentration C2 (unit: [ppm]) is detected and the detected CO gas concentration (unit: [ppm]) is equal to or higher than the predetermined first gas alarm concentration A1. Notify the first alarm that the gas has become abnormal, and the detected CH _Four When the gas concentration exceeds a predetermined second gas alarm concentration A2, CH _Four It has a function of notifying a second alarm that the gas concentration has become abnormal.
[0037]
The gas alarm device 10 has a normal operation mode and an inspection operation mode.
[0038]
As an example, the gas sensor 12 includes CO gas 11A and CH _Four Type that detects gas 11B with one sensor (CO / CH _Four Sensor) and a heater 122 and a sensor element 124. One end of the heater 122 is connected to the collector of the pnp type transistor Q1 of the heating driving means 14, and the other end is grounded. The sensor element 124 is connected to the input port P3 of the CPU 164 of the operation mode control means 162, and the gas atmosphere of the measurement target gas (that is, the CO gas atmosphere or CH _Four It has a function of detecting these gas concentrations by bringing it into contact with a gas atmosphere. Specifically, when the sensor element 124 comes into contact with the detection target gas, the detection voltage starts to rise in response to the gas concentration of each gas atmosphere, and this detection voltage is applied to the input port P3 of the CPU 164.
[0039]
The output response characteristic of the gas sensor 12 is determined by the output response characteristic of the sensor element 124 itself and the timing of gas exposure.
[0040]
FIG. 3 is a timing chart for explaining the generation timing of the enable signal 16e in the normal operation mode, that is, the gas detection timing in the gas alarm device 10 of FIG.
[0041]
FIG. 4 is a timing chart for explaining the generation timing of the enable signal 16e in the inspection operation mode, that is, the gas detection timing in the gas alarm device 10 of FIG.
[0042]
The heating drive means 14 includes a pnp transistor Q1 having an emitter connected to the power supply Vcc and a collector connected to the heater 122 of the gas sensor 12, a resistor R1 connected between the emitter and base of the transistor Q1, and a base of the transistor Q1. And a resistor R2 connected between the output port P4 of the CPU 164 of the operation mode control means 16, and heating for operating the heater 122 based on the first gas mode heating signal 16a or the second gas mode heating signal 16b. It has a function of generating the signal 14a.
[0043]
When the first gas mode heating signal 16a or the second gas mode heating signal 16b from the CPU 164 is given to the base of the transistor Q1, the transistor Q1 is based on the first gas mode heating signal 16a or the second gas mode heating signal 16b. Thus, the heating signal 14a for operating the heater 122 can be generated.
[0044]
As shown in FIGS. 3 and 4, the first gas mode heating signal 16 a is given by a heating voltage VHL (unit: [V]) for heating the heater 122. Similarly, the second gas mode heating signal 16b is given by a heating voltage VHH (unit: [V]) higher than the heating voltage VHL.
[0045]
Specifically, as shown in FIGS. 3 and 4, the heating driving means 14 changes the temperature of the gas sensor 12 to a low temperature range of about 70 to 100 ° C. in response to the first gas mode heating signal 16a. The heating signal 14a for controlling the heater 122 is generated only for a period of 5 to 20 seconds.
[0046]
Similarly, in response to the second gas mode heating signal 16b, the temperature of the gas sensor 12 is set to a high temperature range of about 350 to 400 ° C. for a period of T1 (= 3 to 5 seconds), and a heating signal for controlling the heater 122. 14a is generated.
[0047]
The operation mode control means 16 is configured around the CPU 164, and further includes a first reference voltage generation unit for setting a first gas alarm level V1 corresponding to the first gas alarm concentration A1, and a second gas. A second reference voltage generation unit for setting the second gas alarm level V2 corresponding to the alarm concentration A2.
[0048]
The first reference voltage generation unit includes a resistor R7 connected in series between the power source Vcc and the ground, and an electronic volume VR1 that is variably controlled by a control signal from the output port P7 of the CPU 164. The first gas alarm level V1 is determined by a voltage division ratio (that is, VR1 / (VR1 + R7) between the resistance value of VR1 and the resistance value of resistor R7 obtained by adjusting the electronic volume VR1, and is input to the input port P1 of the CPU 164. Is output.
[0049]
Similarly, the second reference voltage generation unit includes a resistor R9 connected in series between the power supply voltage Vcc and the ground, an electronic volume VR2 variably controlled by a control signal from the output port P7 of the CPU 164, and a resistor R9. Yes. The second gas alarm level V2 is determined by a voltage dividing ratio (ie, VR2 / (VR2 + R9) between the resistance value of VR2 and the resistance value of resistor R9 obtained by adjusting the electronic volume VR2, and is input to the input port P2 of the CPU 164. Is output.
[0050]
The operation mode control means 16 detects the detected first gas concentration C1 (that is, the gas concentration signal 12a) during the detection period T2 of the first gas concentration C1 that is the gas concentration of the CO gas 11A in the low temperature range. When the first gas alarm concentration A1 is reached, it has a function of notifying the first alarm that the CO gas 11A has become abnormal.
[0051]
Further, the operation mode control means 16 performs the CH operation in the above-mentioned high temperature range. _Four When the detected second gas concentration C2 (that is, the gas concentration signal 12a) reaches the second gas alarm concentration A2 during the detection period T1 of the second gas concentration C2, which is the gas concentration of the gas 11B, CH _Four It has a function of notifying a second alarm that gas has become abnormal.
[0052]
The sensor control unit 162 provided in the operation mode control means 16 includes a pnp transistor Q2 having an emitter connected to the power supply Vcc and a collector connected to the sensor element 124 as a load via a resistor R4, a power supply Vcc, A resistor R5 connected between the base of the transistor Q2, a resistor R6 connected between the base of the transistor Q2 and the output port P5 of the CPU 164, and between the power supply Vcc and the sensor element 124 for supplying a bias current to the sensor element 124. The resistor R3 is connected.
[0053]
The sensor control unit 162 detects the first gas concentration C1 during the normal operation mode. During T2 At a predetermined timing (that is, a CO gas detection point indicated by “white circle” in FIG. 3) while the first gas mode heating signal 16a related to the first gas 11A is being applied. , Alternatively, a predetermined timing (that is, CH indicated by “black circle” in FIG. 3) while the second gas mode heating signal 16b is applied. _Four At the gas detection point), the gas sensor 12 has a function of generating an enable signal 16e for commanding generation of the gas concentration signal 12a related to the first gas 11A or the second gas 11B.
[0054]
Further, in the inspection operation mode, the sensor control unit 162 detects the first gas concentration C1 as shown in FIG. During T2 The first gas 11A or the second gas 11B in the gas sensor 12 is always applied while the first gas mode heating signal 16a related to the first gas 11A is applied, or while the second gas mode heating signal 16b is applied. It has a function of generating an enable signal 16e for instructing generation of the gas concentration signal 12a.
[0055]
The CPU 164 outputs the enable signal 16e from the output port P5 and controls the transistor Q2, thereby taking in the gas concentration signal 12a from the sensor element 124 from the input terminal P3.
[0056]
The alarm means 18 comprises an npn transistor Q3 whose base is connected to the output port P6 of the CPU 164, and a buzzer 182 (Bz in the figure) connected between the collector and the power source Vcc as the collector load of the transistor Q3.
[0057]
The CPU 164 performs control for giving the first gas mode alarm signal 16c or the second gas mode alarm signal 16d to the base of the transistor Q3 from the output terminal P6 and prompting the generation of the alarm sound 18a.
[0058]
Next, the operation of the gas alarm device 10 will be described. To summarize the operation of the gas alarm device 10, in order to confirm the operation of the gas sensor 12, that is, whether or not the gas sensor 12 normally detects gas when the gas alarm device 10 is installed at the installation location, the inspection gas is used. An inspection operation for spraying the gas sensor 12 is performed.
[0059]
Therefore, after the gas alarm device 10 is turned on and after an initial delay of a predetermined time (for example, 1 minute), the operation mode control means 16 provides a check operation mode period for a predetermined time (for example, 3 minutes). During this period, inspection is performed by blowing inspection gas. During the inspection operation mode, the operation mode control means 16 always detects the gas concentration with the gas sensor 12 during the gas concentration detection period, and when the detected concentration of the inspection gas exceeds the alarm concentration, the buzzer 182 of the alarm means 18. The ringing is started and the ringing is forcibly stopped after a predetermined time.
[0060]
Thereafter, when the buzzer 182 of the alarm means 18 rings even once during the inspection operation mode, the gas alarm device 10 immediately changes the operation mode from the inspection operation mode to the normal operation mode without waiting for the end of the inspection operation mode period. After the switching, the operation is performed in the normal operation mode, and when the gas concentration equal to or higher than the alarm concentration is detected, the buzzer 182 of the alarm means 18 is sounded to notify the alarm.
[0061]
Next, the operation of the gas alarm device 10 of FIG. 1 will be described in detail with reference to the flowcharts of FIGS. 5 and 6. The operation of the gas alarm device 10 is performed based on the processing of the CPU 164 of the operation mode control means 16. First, in the flowchart of FIG. 5, the gas alarm device 10 is first turned on (step S11), and then waits for an initial delay time (for example, 60 seconds) until the stable operation of the circuit is reached (step S12). ). During this time, for cleaning the gas sensor 12, the transistor Q1 is turned on by the cleaning heating signal from the output port P4 of the CPU 164, and the heater 122 is heated up.
[0062]
When the initial delay ends, the CPU 164 then starts a built-in inspection operation mode timer (not shown in FIG. 2) (step S13), and then checks the inspection operation mode period by counting the inspection operation mode timer. It is determined whether 180 seconds (3 minutes) have elapsed (step S14). If 180 seconds (3 minutes) have not elapsed, the CPU 164 starts the inspection operation mode (step S15).
[0063]
With the start of this inspection operation mode, the CPU 164 applies the first gas mode heating signal 16a and the second gas mode heating signal 16b to the base of the transistor Q1 from the output port P4. Thereby, the transistor Q1 generates a heating signal 14a as shown in FIG. 4 and drives the heater 122 of the gas sensor 12.
[0064]
Next, the CPU 164 sets the first gas alarm concentration A1 and the second gas alarm concentration A2 to, for example, the first gas alarm concentration A1i for the inspection operation mode to 150 ppm, and sets the second gas alarm concentration A2i for the inspection operation mode. For example, it is set to 3000 ppm (step S16).
[0065]
This setting is performed as follows. That is, the CPU 164 outputs the control signal for the inspection operation mode level from the output port P7 to the electronic volumes VR1 and VR2, thereby causing the first gas alarm level V1 of the first reference voltage generation unit and the second reference voltage generation unit. And the second gas alarm level V2 are set to the inspection operation mode first gas alarm level V1i and the inspection operation mode second gas alarm level V2i, respectively. The inspection operation mode first gas alarm level V1i and the inspection operation mode second gas alarm level V2i set in this way are respectively the inspection operation mode first gas alarm concentration A1i, for example, 150 ppm, and the inspection operation mode. A reference voltage corresponding to the second gas alarm concentration A2i, for example, 3000 ppm, is applied to the input ports P1 and P2 of the CPU 164.
[0066]
Next, the CPU 164 determines whether or not the gas concentration detected by the sensor element 124 of the gas sensor 12 is 150 ppm or more when the CO gas 11A is sprayed as the inspection gas, or CH as the inspection gas. _Four When the gas 11B is sprayed, it is determined whether it is 3000 ppm or more (step S17). This determination is made when the CPU 164 always detects the sensor element 124 of the gas sensor 12 during the detection period of the gas concentrations of T1 and T2 by the control of the sensor control unit 162 by the enable signal 16e from the output port P5 as shown in FIG. The detection voltage (gas concentration signal 12a) is acquired from the input port P3, and it is determined by determining whether or not the acquired detection voltage is equal to or higher than the first gas alarm level V1 or the second gas alarm level V2.
[0067]
Next, if the answer to step S17 is yes, the CPU 164 starts a built-in alarm timer (not shown) (step S18), and then outputs a control signal from the output port P6 to turn on the transistor Q3. When the inspection gas is the CO gas 11A, the concentration C1 of the CO gas 11A becomes an abnormal value equal to or higher than the first gas alarm concentration A1 (= 150 ppm). The first alarm indicating that the _Four In the case of gas 11B, CH _Four A second alarm is notified that the concentration C2 of the gas 11B has become an abnormal value equal to or higher than the second gas alarm concentration A2 (= 3000 ppm) (step S19).
[0068]
Next, the CPU 164 determines whether or not a predetermined time (for example, 3 seconds) has elapsed from the count of the alarm timer (step S20). If 3 seconds have not elapsed, the process returns to step S19 to continue the alarm by sounding the buzzer 182.
[0069]
If 3 seconds have elapsed, the CPU 164 stops the alarm (step S21), then resets the alarm timer (step S22), and then switches the operation mode from the inspection operation mode to the normal operation mode. Is performed (step S10).
[0070]
On the other hand, if 180 seconds (3 minutes) have elapsed in step S14, the CPU 164 resets the inspection operation mode timer (step S23), and then switches the operation mode from the inspection operation mode to the normal operation mode. Processing is performed (step S10).
[0071]
Next, the operation in the normal operation mode performed in step S10 will be described with reference to the flowchart of FIG.
[0072]
When the operation mode is switched from the inspection operation mode to the normal operation mode, the CPU 164 first sets the first gas alarm concentration A1 and the second gas alarm concentration A2 to the normal operation mode first gas alarm concentration A1n and the normal operation mode, respectively. The mode second gas alarm concentration A2n is set. In this embodiment, the inspection operation mode first gas alarm concentration A1i and the normal operation mode first gas alarm concentration A1n are set to be the same, and the inspection operation mode second gas alarm concentration A2i and the normal operation mode second gas. Since the alarm concentration A2n is also set to be the same, the first gas alarm concentration A1n for normal operation mode is set to 150 ppm, and the second gas alarm concentration A2n for normal operation mode is set to 3000 ppm (step S101).
[0073]
This setting is performed by outputting a normal operation mode control signal having the same level as the inspection operation mode level from the output port P7 of the CPU 164 to the electronic volumes VR1 and VR2.
[0074]
Next, the CPU 164 determines whether the gas concentration detected by the sensor element 124 of the gas sensor 12 is 150 ppm or more in the case of the CO gas 11A, or CH _Four In the case of the gas 11B, it is determined whether it is 3000 ppm or more (step S102). This determination is performed by the CPU 164 at a predetermined timing determined by the control of the sensor control unit 162 using the enable signal 16e from the output port P5 (that is, the CO gas detection point or CH shown in FIG. 3). _Four Gas detection point), the detection voltage (gas concentration signal 12a) of the sensor element 124 of the gas sensor 12 is acquired from the input port P3, and is the acquired detection voltage equal to or higher than the first gas alarm level V1 or the second gas alarm level V2? This is done by determining whether or not.
[0075]
Next, if the answer to step S102 is YES, the CPU 164 outputs the first gas mode alarm signal 16c or the second gas mode alarm signal 16d from the output port P6 to control the transistor Q3 to be turned on. When the detected gas is the CO gas 11A by ringing the buzzer 182, the concentration C1 of the CO gas 11A has become an abnormal value equal to or higher than the first gas alarm concentration AIn (= 150 ppm) for the normal operation mode. The first alarm is notified and the detected gas is CH. _Four In the case of gas 11B, CH _Four A second alarm is notified that the concentration C2 of the gas 11B has become an abnormal value equal to or higher than the second gas alarm concentration A2n (= 3000 ppm) for normal operation mode (step S103).
[0076]
As described above, according to the first embodiment of the present invention, the normal operation mode and the inspection operation mode are provided, and the gas concentration is always detected and detected by the gas sensor 12 during the gas concentration detection period in the inspection operation mode. When the concentration of the inspection gas reaches or exceeds the alarm concentration, the buzzer 182 of the alarm means 18 starts sounding, and the sounding is forcibly stopped after a predetermined time has passed, immediately without waiting for the end of the inspection operation mode period. Since the operation mode is switched from the inspection operation mode to the normal operation mode, the inspection work can be performed in a shorter time than before.
[0077]
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the first gas alarm concentration A1i for the inspection operation mode and the first gas alarm concentration A1n for the normal operation mode are set to be the same, and the second gas alarm concentration A2i for the inspection operation mode and the normal operation mode are set. The second gas alarm concentration A2n for the operation is set to be the same, but in the second embodiment, the first gas alarm concentration A1i for the inspection operation mode is set lower than the first gas alarm concentration A1n for the normal operation mode. The inspection operation mode second gas alarm concentration A2i is set lower than the normal operation mode second gas alarm concentration A1n.
[0078]
Hereinafter, the operation of the gas alarm device 10 according to the second embodiment of the present invention will be described with reference to the flowchart of FIG. First, the gas alarm device 10 is powered on (step S11), and then waits for an initial delay time (for example, 60 seconds) until the stable operation of the circuit is reached (step S12). During this time, for cleaning the gas sensor 12, the transistor Q1 is turned on by the cleaning heating signal from the output port P4 of the CPU 164, and the heater 122 is heated up.
[0079]
When the initial delay is finished, the CPU 164 then starts a built-in inspection operation mode timer (step S13), and then the inspection operation mode timer counts 180 seconds (3 minutes) as a result of the inspection operation mode timer count. It is determined whether or not it has elapsed (step S14). If 180 seconds (3 minutes) have not elapsed, the CPU 164 starts the inspection operation mode (step S15).
[0080]
With the start of this inspection operation mode, the CPU 164 applies the first gas mode heating signal 16a and the second gas mode heating signal 16b to the base of the transistor Q1 from the output port P4. Thereby, the transistor Q1 generates a heating signal 14a as shown in FIG. 3 and drives the heater 122 of the gas sensor 12.
[0081]
Next, the CPU 164 sets the first gas alarm concentration A1 and the second gas alarm concentration A2 to the inspection operation mode first gas alarm concentration A1i, for example, lower than the normal operation mode first gas alarm concentration A1n (= 150 ppm), for example. The second gas alarm concentration for inspection operation mode A2i, for example, 500 ppm, which is lower than 50 ppm and the second gas alarm concentration for normal operation mode A2n (= 3000 ppm) (step S16).
[0082]
This setting is performed as follows. That is, the CPU 164 outputs the control signal for the inspection operation mode level from the output port P7 to the electronic volumes VR1 and VR2, thereby causing the first gas alarm level V1 of the first reference voltage generation unit and the second reference voltage generation unit. And the second gas alarm level V2 are set to the inspection operation mode first gas alarm level V1i and the inspection operation mode second gas alarm level V2i, respectively. The first gas alarm level V1i for inspection operation mode and the second gas alarm level V2i for inspection operation mode set in this way are respectively the first gas alarm concentration A1i for inspection operation mode, for example, 50 ppm, and for inspection operation mode. A reference voltage corresponding to the second gas alarm concentration A2i, for example, 500 ppm, is applied to the input ports P1 and P2 of the CPU 164.
[0083]
Next, the CPU 164 determines whether the gas concentration detected by the sensor element 124 of the gas sensor 12 is 50 ppm or more when the CO gas 11A is sprayed as the inspection gas, or CH as the inspection gas. _Four When the gas 11B is sprayed, it is determined whether it is 500 ppm or more (step S17). This determination is made when the CPU 164 always detects the sensor element 124 of the gas sensor 12 during the detection period of the gas concentrations of T1 and T2 by the control of the sensor control unit 162 by the enable signal 16e from the output port P5 as shown in FIG. The detection voltage (gas concentration signal 12a) is taken from the input port P3, and it is determined whether or not the taken detection voltage is equal to or higher than the inspection operation mode first gas alarm level V1i or the inspection operation mode second gas alarm level V2i. Is done.
[0084]
Next, if the answer to step S17 is yes, the CPU 164 starts a built-in alarm timer (not shown) (step S18), and then outputs a control signal from the output port P6 to turn on the transistor Q3. When the inspection gas is the CO gas 11A by controlling so that the buzzer 182 sounds, the concentration C1 of the CO gas 11A is not less than the inspection mode first gas alarm concentration A1i (= 50 ppm). The first alarm to the effect that _Four In the case of gas 11B, CH _Four A second alarm indicating that the concentration C2 of the gas 11B has become an abnormal value equal to or higher than the inspection mode second gas alarm concentration A2i (= 500 ppm) is notified (step S19).
[0085]
Next, the CPU 164 determines whether or not a predetermined time (for example, 3 seconds) has elapsed from the count of the alarm timer (step S20). If 3 seconds have not elapsed, the process returns to step S19 to continue the alarm by sounding the buzzer 182.
[0086]
If 3 seconds have elapsed, the CPU 164 stops the alarm (step S21), then resets the alarm timer (step S22), and then switches the operation mode from the inspection operation mode to the normal operation mode. The process according to FIG. 6 is performed (step S10).
[0087]
On the other hand, if 180 seconds (3 minutes) have elapsed in step S14, the CPU 164 resets the inspection operation mode timer (step S23), and then switches the operation mode from the inspection operation mode to the normal operation mode. Processing (see FIG. 6) is performed (step S10).
[0088]
Next, the operation in the normal operation mode performed in step S10 in the second embodiment will be described with reference to the flowchart of FIG.
[0089]
When the operation mode is switched from the inspection operation mode to the normal operation mode, the CPU 164 first sets the first gas alarm concentration A1 and the second gas alarm concentration A2 to the first gas alarm concentration A1i (= 50 ppm) for the inspection operation mode, respectively. ) And the second gas alarm concentration for inspection operation mode A2i (= 500 ppm), the first gas alarm concentration for normal operation mode A1n, for example 150 ppm, and the second gas alarm concentration for normal operation mode A2n, for example, 3000 ppm are changed. (Step S101).
[0090]
This setting is performed as follows. That is, the CPU 164 outputs a control signal at a level for the normal operation mode from the output port P7 to the electronic volumes VR1 and VR2, thereby causing the first gas alarm level V1 of the first reference voltage generation unit and the second reference voltage generation unit. And the second gas alarm level V2 are set to the first gas alarm level V1n for normal operation mode and the second gas alarm level V2n for normal operation mode, respectively. The first gas alarm level V1n for normal operation mode and the second gas alarm level V2n for normal operation mode set in this way are the first gas alarm concentration A1n for normal operation mode, for example, 150 ppm, and for the normal operation mode, respectively. A reference voltage corresponding to the second gas alarm concentration A2n, for example, 3000 ppm, is applied to the input ports P1 and P2 of the CPU 164.
[0091]
Next, the CPU 164 determines whether the gas concentration detected by the sensor element 124 of the gas sensor 12 is 150 ppm or more in the case of the CO gas 11A, or CH _Four In the case of the gas 11B, it is determined whether it is 3000 ppm or more (step S102). This determination is performed by the CPU 164 at a predetermined timing determined by the control of the sensor control unit 162 using the enable signal 16e from the output port P5 (that is, the CO gas detection point or CH shown in FIG. 3). _Four At the gas detection point), the detection voltage of the sensor element 124 of the gas sensor 12 is taken from the input port P3, and the taken detection voltage (gas concentration signal 12a) is the first gas alarm level V1n for the normal operation mode or the second for the normal operation mode. This is performed by determining whether or not the gas alarm level is V2n or higher.
[0092]
Next, if the answer to step S102 is YES, the CPU 164 outputs the first gas mode alarm signal 16c or the second gas mode alarm signal 16d from the output port P6 to control the transistor Q3 to be turned on. When the detected gas is the CO gas 11A by ringing the buzzer 182, the concentration C1 of the CO gas 11A has become an abnormal value equal to or higher than the first gas alarm concentration AIn (= 150 ppm) for the normal operation mode. The first alarm is notified and the detected gas is CH. _Four In the case of gas 11B, CH _Four A second alarm is notified that the concentration C2 of the gas 11B has become an abnormal value equal to or higher than the second gas alarm concentration A2n (= 3000 ppm) for normal operation mode (step S103).
[0093]
Thus, according to the second embodiment of the present invention, in the inspection operation mode, the detected concentration of the inspection gas becomes equal to or higher than the inspection operation mode alarm concentration set lower than the normal operation mode alarm concentration. In this case, the alarm is notified, so that the low concentration gas can be inspected in a short time, and the sensor can be avoided from the high concentration gas.
[0094]
As described above, the embodiment of the present invention has been described. However, the present invention is not limited to this, and various modifications and applications are possible.
[0095]
For example, in the above-described first embodiment, the first and second reference voltage generation units are configured by the resistors R7 and R9 and the electronic volumes VR1 and VR2. However, other configurations may be employed.
[0096]
Further, the alarm time (for example, 3 seconds) in the inspection operation mode is an example, and other time may be used, and preferably 3 to 5 seconds.
[0097]
【The invention's effect】
According to the first aspect of the present invention, the inspection work can be performed in a shorter time than before.
[0098]
According to the invention described in claim 2, the inspection work can be performed in a shorter time than before.
[0099]
According to the third aspect of the invention, the inspection work can be performed in a short time with a low-concentration gas, and when the alarm is notified, the inspection gas is moved away from the gas sensor. Thus, it is possible to avoid the continuous sounding and re-sounding of the alarm means at the time of inspection as in the prior art.
[0100]
According to the invention described in claim 4, the inspection work can be performed in a shorter time than before.
[0101]
According to invention of Claim 5, the gas concentration with respect to multiple types of gas is detectable with one gas sensor.
[0102]
According to the sixth aspect of the present invention, the heater 122 of the gas sensor 12 can be heated to the appropriate temperatures of the two types of gases.
[0103]
According to the seventh aspect of the present invention, it is possible to generate a gas concentration signal at a predetermined timing so as not to cause a detection error, and it is possible to confirm the inspection in a short time.
[0104]
According to the eighth aspect of the invention, the inspection work can be performed in a shorter time than before.
[0105]
According to the ninth aspect of the invention, the inspection work can be performed in a short time with a low-concentration gas, and the inspection gas is moved away from the gas sensor when an alarm is notified. Thus, it is possible to avoid the continuous sounding and re-sounding of the alarm means at the time of inspection as in the prior art.
[0106]
According to the tenth aspect of the present invention, the heater of the gas sensor can be controlled to be heated to the appropriate temperature of each of the two types of gases.
[0107]
According to the eleventh aspect of the present invention, it is possible to generate a gas concentration signal at a predetermined timing so that no detection error occurs, and it is possible to confirm the inspection in a short time.
[0108]
According to the twelfth aspect of the invention, when the gas alarm is attached to the installation place, the inspection can be performed in a short time before the normal operation is performed.
[0109]
According to the invention described in claim 13, when the gas alarm is attached to the installation place, the inspection can be performed with the low-concentration gas before the normal operation is performed, and the inspection time can be greatly shortened. Can do.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a gas alarm device according to the present invention.
FIG. 2 is a circuit diagram showing a first embodiment of a gas alarm device according to the present invention.
3 is a timing chart for explaining gas detection timing in a normal operation mode in the gas alarm device of FIG. 2; FIG.
4 is a timing chart for explaining gas detection timing in an inspection operation mode in the gas alarm device of FIG. 2; FIG.
FIG. 5 is a flowchart for explaining the operation of the gas alarm device of FIG. 2;
6 is a flowchart for explaining the operation of the gas alarm device of FIG. 2;
FIG. 7 is a flowchart for explaining the operation of the gas alarm device according to the second embodiment of the present invention.
[Explanation of symbols]
10 Gas alarm
12 Gas sensor
14 Heating drive means
16 Operation mode control means
18 Alarm means
122 Heater
124 Sensor element
162 Sensor control unit

Claims

The gas sensor temperature is periodically changed alternately between the low temperature range and the high temperature range, and the gas concentration detected by the gas sensor is equal to or higher than the predetermined alarm concentration during the gas concentration detection period of either the low temperature range or the high temperature range. In the gas alarm device that notifies the alarm that the gas concentration has become abnormal,
An operation mode control means for controlling switching between a normal operation mode and an inspection operation mode, and in the normal operation mode, the gas concentration is detected by the gas sensor at one detection point during the gas concentration detection period, and the detected gas concentration When the gas concentration exceeds the alarm concentration, a warning that the gas concentration has become abnormal is reported, and in the inspection operation mode, the gas sensor always detects the gas concentration from the beginning to the end of the gas concentration detection period, A gas alarm device comprising an operation mode control means for notifying that a gas concentration has become abnormal when the detected gas concentration exceeds an alarm concentration.

In the inspection operation mode, the operation mode control means always detects the gas concentration with the gas sensor from the beginning to the end of the gas concentration detection period , and when the detected gas concentration exceeds the alarm concentration, the gas concentration is The gas alarm device according to claim 1, wherein an alarm indicating that an abnormality has occurred is started and the alarm is forcibly stopped after a predetermined time has elapsed.

The gas sensor temperature was changed alternately between the low temperature range and the high temperature range periodically, and the gas concentration detected by the gas sensor exceeded the predetermined alarm concentration during the detection period of either the low temperature range or the high temperature range . At the time of the gas alarm that notifies the alarm that the gas concentration has become abnormal,
An operation mode control means for controlling switching between a normal operation mode and an inspection operation mode, wherein in the normal operation mode, the gas sensor detects a gas concentration at one detection point during a gas concentration detection period, and the detected gas concentration gas but upon a normal operation mode for the alarm concentration or more, an alarm about a warning to the effect that the gas concentration has become abnormal, the inspection operation mode, always the gas sensor from the beginning to the end of the detection period of the gas concentration Operation mode control that detects the gas concentration and detects an alarm that the gas concentration is abnormal when the detected gas concentration is higher than the alarm concentration for inspection mode set lower than the alarm concentration for normal operation mode A gas alarm device comprising means.

In the inspection operation mode, the operation mode control means always detects the gas concentration with the gas sensor from the beginning to the end of the gas concentration detection period , and the detected gas concentration is set lower than the alarm concentration for the normal operation mode. 4. The gas alarm device according to claim 3 , wherein an alarm that the gas concentration has become abnormal is started when the mode alarm concentration is exceeded, and the alarm is forcibly stopped after a predetermined time.

The said gas sensor has a sensor element which detects the gas concentration with respect to two types of gas, and produces | generates a gas concentration signal, The heater which heats this sensor element, The any one of Claim 1 to 4 characterized by the above-mentioned. Gas alarm device as described in.

The operation mode control means for generating a first gas mode heating signal and a second gas mode heating signal for heating the sensor element corresponding to each of the two kinds of gases during the gas concentration detection period;
The gas alarm device according to claim 5, further comprising: a heating drive unit that generates a heating signal for operating the heater based on the first gas mode heating signal or the second gas mode heating signal. .

In the normal operation mode, the operation mode control unit is configured to detect the gas sensor at one detection point while the first gas mode heating signal is being applied or while the second gas mode heating signal is being applied. While generating an enable signal for commanding generation of the gas concentration signal, and during the inspection operation mode, while the first gas mode heating signal is being applied and while the second gas mode heating signal is being applied The gas alarm device according to claim 5, further comprising: a sensor control unit that generates an enable signal for instructing generation of the gas concentration signal in the gas sensor from the beginning to the end of the gas sensor.

The temperature of the gas sensor is alternately and periodically changed between a low temperature region and a high temperature region, the first gas concentration of the first gas is detected in the low temperature region, and the second gas concentration of the second gas is further detected in the high temperature region. When the first gas concentration is equal to or higher than the first gas alarm concentration, the first alarm is notified that the first gas concentration is abnormal, and the second gas concentration is equal to or higher than the second gas alarm concentration. In the gas alarm device for notifying the second alarm that the second gas concentration has become abnormal,
In the normal operation mode, the operation mode control means detects the first gas concentration with the gas sensor at one detection point during the detection period of the first gas concentration, and the detected first gas concentration is the first gas alarm concentration. When this occurs, a first alarm is sent to the effect that the first gas concentration has become abnormal, and the second gas concentration is detected by the gas sensor at one detection point during the second gas concentration detection period. When the detected second gas concentration becomes equal to or higher than the second gas alarm concentration, a second alarm indicating that the second gas concentration has become abnormal is notified, and in the inspection operation mode, the first gas concentration When the first gas concentration is always detected by the gas sensor from the beginning to the end of the detection period , and the detected first gas concentration is equal to or higher than the first gas alarm concentration, the first gas concentration becomes abnormal. The first alarm of Forcibly stops the first alarm after a constant time, and, second gas concentration at all times from beginning to end by detecting a second gas concentration in the gas sensor, it is detected in the detection period of the second gas concentration second 6. When the gas alarm concentration is exceeded, a second alarm indicating that the second gas concentration is abnormal is started, and the second alarm is forcibly stopped after a predetermined time has elapsed. 8. The gas alarm device according to any one of 7 above.

The temperature of the gas sensor is alternately and periodically changed between a low temperature region and a high temperature region, the first gas concentration of the first gas is detected in the low temperature region, and the second gas concentration of the second gas is further detected in the high temperature region. When the first gas concentration is equal to or higher than the first gas alarm concentration, the first alarm is notified that the first gas concentration is abnormal, and the second gas concentration is equal to or higher than the second gas alarm concentration. In the gas alarm device for notifying the second alarm that the second gas concentration has become abnormal,
In the normal operation mode, the operation mode control means detects the first gas concentration with the gas sensor at one detection point during the detection period of the first gas concentration, and the detected first gas concentration is used for the normal operation mode. When the gas concentration exceeds 1 gas alarm concentration, a first alarm indicating that the first gas concentration has become abnormal is notified, and at the one detection point during the detection period of the second gas concentration, the second gas sensor is used. When the gas concentration is detected and the detected second gas concentration is equal to or higher than the second gas alarm concentration for the normal operation mode, a second alarm is notified that the second gas concentration has become abnormal, and an inspection is performed. the operation mode, always from the beginning to the end of the detection period of the first gas concentration detecting a first gas concentration in the gas sensor, the detected first gas concentration was set lower than the first gas alarm concentration for the normal operation mode When the first gas alarm concentration for the detection operation mode becomes equal to or higher than the first alarm, the first alarm that the first gas concentration becomes abnormal is started, the first alarm is forcibly stopped after a predetermined time, and For the inspection operation mode in which the second gas concentration is always detected by the gas sensor from the beginning to the end of the detection period of the second gas concentration, and the detected second gas concentration is set lower than the second gas alarm concentration for the normal operation mode. The second alarm that the second gas concentration becomes abnormal is started when the concentration exceeds the second gas alarm concentration, and the second alarm is forcibly stopped after a predetermined time. The gas alarm device according to any one of 5 to 7.

The operation mode control means generates the first gas mode heating signal for heating the sensor element to the low temperature region during the detection period of the first gas concentration, and during the detection period of the second gas concentration. The gas alarm according to claim 8 or 9, wherein the gas alarm is configured to generate the second gas mode heating signal for heating the sensor element to the high temperature range.

In the normal operation mode, the sensor control unit is configured to detect at one detection point while the first gas mode heating signal related to the first gas is being applied during the detection period of the first gas concentration or at the second time. The gas concentration signal related to the first gas or the second gas in the gas sensor at one detection point while the second gas mode heating signal related to the second gas is being applied during a gas concentration detection period. And generating the enable signal for commanding the generation of the first gas mode while the first gas mode heating signal related to the first gas is applied during the detection period of the first gas concentration in the inspection operation mode . always from the beginning to the end while the second gas mode heating signal always or according to the second gas during the detection period of the second gas concentration from beginning to end is applied 11. The apparatus according to claim 8, wherein the enable signal for commanding generation of the gas concentration signal related to the first gas or the second gas in the gas sensor is generated. The gas alarm device according to item.

The operation mode control means operates the gas alarm in the inspection operation mode for a predetermined time when the power is turned on, and operates the gas alarm from the inspection operation mode to the normal operation mode after the predetermined time elapses. The gas alarm device according to any one of claims 1 to 11.

3. The gas according to claim 1, wherein the operation mode control unit operates the gas alarm device in the inspection operation mode when the power is turned on, and switches to the normal operation mode after the alarm is stopped in the inspection operation mode. Alarm.