201246138 六、發明說明： 【發明所屬之技術領域】 本發明係有關檢測瓦斯器具或瓦斯管線洩漏之天然氣 、液化石油氣等可燃性氣體，並發出警報之瓦斯洩漏警報 器，特別是以電池作爲電源之電池式瓦斯警報器。 【先前技術】 檢測瓦斯器具或瓦斯管線之瓦斯洩漏，並以語音或蜂 鳴器等發出警報，通知瓦斯使用者有瓦斯洩漏情形之瓦斯 警報器，係廣爲人知。 瓦斯警報器係藉由氣體感測器等氣體檢測元件來檢測 出受檢氣體，當受檢氣體的氣體濃度超過規定之氣體濃度 時，以警報音或警報顯示來發出警報。 在瓦斯警報器中，爲檢測出天然氣或液化石油氣等受 檢氣體，會使用氣體感測器。氣體感測器具有例如加熱器 電阻與感測器電阻。其中感測器電阻會與受檢氣體產生反 應，而改變其電阻値。再藉由已加熱之加熱器電阻，來測 量感測器電阻之電阻値，以進行氣體檢測。例如對氣體感 測器之加熱器電阻施加電壓，使加熱器溫度處於規定溫度 如400°C等之狀態，並測量上述感測器電阻之電阻値（實 務上爲該電阻値所示之電壓等）的變化，藉此進行氣體檢 測。 要令氣體感測器之加熱器溫度達到規定溫度，其驅動 方法有施加直流電壓之方法，或施加脈衝電壓之方法，但 -5- 201246138 在以電池驅動之電池式瓦斯笤報器中，爲求省電，多採用 以規定之驅動周期對加熱器進行脈衝通電之方法（專利文 獻1、專利文獻2 )。 圖8爲以脈衝通電來驅動感測器之一例。感測器驅動 周期爲45秒，每一週期對氣體感測器進行10 0ms之脈衝 通電，並於脈衝通電結束之時間點，進行氣體檢測。爲求 省電，會縮短脈衝通電時間（對氣體感測器施加電壓之時 間，本例中爲1 〇〇ms )，以便能在短時間完成氣體檢測， 同時加長驅動周期，以便省電地驅動感測器》 瓦斯笤報器，在高濃度（1 2500ppm )瓦斯環境實驗中 ，必須在瓦斯洩漏發生後60秒以內，檢測出該瓦斯洩漏 發生，並發出啓報（專利文獻3)。 對此，電池驅動式之瓦斯警報器如上所述，爲求省電 ，係採用以規定之驅動周期進行脈衝通電之方法。然而該 方法僅在規定的驅動周期時間點進行氣體檢測，而非隨時 進行氣體檢測，故要在60秒以內檢測出瓦斯並發出瞢報 ，恐有困難。 此外，基於免電線方便安裝或機器小型化等理由，而 有電池驅動式瓦斯警報器之需求，但在檢測受檢氣體時， 須將氣體感測器的加熱器加熱至4 0 0 °C左右，這會耗費大 量的電力。因此，在瓦斯警報器5年的有效期限內，如何 以電池省電地驅動感測器，便成爲課題。 〔專利文獻1〕 日本特開1999-248659號公報 〔專利文獻2〕 日本特開2003-67867號公報 201246138 〔專利文獻3〕 日本特開2010-86199號公報 【發明內容】 如上所述，在電池式瓦斯警報器中，僅於規定的驅動 周期時間點進行氣體檢測動作，而非隨時（不間斷）進行 氣體檢測，故當遇氣體濃度急遽上昇時，便難以及時在檢 測時間內，及早檢測出瓦斯並發出警報。 專利文獻1，2並未考量此一檢測延遲，而專利文獻3 雖載明以20秒周期進行脈衝驅動之實施例，但其電池耗 電量非常大。爲解決上述課題，可縮短脈衝通電的驅動周 期，增加氣體檢測的時間點；但氣體感測器在通電時，須 將加熱器之溫度加熱至400°C左右，需要大量的電力，電 池消耗量會非常大（例如將驅動周期45秒改爲周期5秒 ，那麼氣體感測器所消費的電力會增加至9倍）。 因此，針對電池式瓦斯警報器，雖然想盡可能拉長脈 衝通電的驅動周期，但驅動周期若是過長，則因驅動周期 以外的時間點並未進行氣體檢測，會使得氣體檢測延遲， 而失去其及早發出警報之原意，導致警報延遲，無法在仍 安全之狀態下即發出警報。（舉例來說，將驅動周期從45 秒改爲周期90秒，那麼氣體感測器所耗費的電力會變爲 1/2，但因每90秒才進行一次檢測，若氣體濃度在這90 秒內有大幅上昇之情形，則可能氣體濃度已大幅超過檢測 濃度後才被檢測出來，造成安全上的疑慮。） 又，氣體感測器檢測周圍之氣體濃度時，其內部之氣 -7- 201246138 體濃度會因眢報器本體構造、氣體感測器構造、或爲過濾 其他氣體而設置之過濾器結構而有所影響，無法即時與周 圍氣體濃度同步，而會較周圍氣體濃度有所延遲，逐漸接 近周圍氣體濃度。因此，在決定驅動周期時，不只要考量 感測器的驅動周期，尙需考量瞥報器構造所造成的氣體濃 度檢測延遲。 本發明之課題即在於提供一種可靠性高的電池式瓦斯 e報器及其控制裝置，係針對以電池作爲電源之電池式瓦 斯昝報器，可抑制電池耗電量達到省電的同時，及早發出 瓦斯洩漏昝報，不會有受檢氣體檢測延遲之情形發生。 本發明之瓦斯普報器，係以電池作爲電源之電池式瓦 斯e報器，依據氣體感測器之輸出來進行瓦斯洩漏檢測， 該氣體感測器會因應受檢氣體之氣體濃度而改變電性；該 電池式瓦斯普報器，其特徵爲，具有以下構成： 感測器驅動手段，係以任意之驅動周期，透過脈衝通 電而驅動前述氣體感測器之手段，正常情形下會以第1驅 動周期來驅動前述氣體感測器；及氣體濃度算出手段，依 據該驅動時前述氣體感測器之輸出，算出氣體濃度：及普 報手段，當該算出之氣體濃度超過規定之第1閾値，發出 θ報。 尙具有：驅動周期變更手段，判定前述氣體濃度算出 手段所算出之氣體濃度，是否超過較前述第1閾値更低之 第2閩値，若氣體濃度超過該第2閾値，則令前述感測器 驅動手段，以較前述第1驅動周期更短之第2驅動周期， -8 - 201246138 來驅動前述氣體感測器》 ，係以 器並檢 2閩値 來檢測 在遇到 漏，不 ,斯管線 警報之 ^瓦斯警 1 1、控 池部1 5 1體開關 SW1 > 利用上述本發明之瓦斯警報器，在正常情形下 較長之驅動周期（第1驅動周期）來驅動氣體感询 測周圍氣體；當氣體濃度超過較第1閩値爲低之第 時，則以較短之感測器驅動周期（第2驅動周期） 周圍氣體。藉此，可抑制電池耗電量以省電，同時 氣體濃度急遽上昇之情形時，可及早檢測出瓦斯搜 會有檢測延遲。 【實施方式】 以下參照圖式，詳細說明本發明之實施形態。 圖1爲本發明瓦斯警報器之實施形態構成圖。 圖中之瓦斯警報器1 〇，係爲檢測瓦斯器具或瓦 洩漏之天然氣、液化石油氣等可燃性氣體，並發出 瓦斯洩漏警報器，特別是以電池作爲電源之電池式 報器》 圖中例示之瓦斯警報器10，具有氣體感測器 制電路部1 2、警報部1 3、周圍溫度檢測部1 4、電 等，更具有由負載電阻R、電晶體開關SW1、電晶 SW2等所構成之圖示電路。又，以下將電晶體開關 電晶體開關SW2簡略記述爲開關SW1、開關SW2 。 檢測受檢氣體之氣體感測器11，具備用以檢測氣體濃 度之感測器電阻1 1 a，及將其加熱之加熱器電阻1 1 b。如 習知之說明，感測器電阻1 1 a的電阻値會因應周圍瓦斯濃 201246138 度而變化，以上述規定之驅動周期進行瓦斯洩漏檢測處理 時，是將加熱器電阻1 1 b加熱至例如400°C，並測量感測 器電阻1 1 a之電阻値（或與該電阻値相應之電壓値等）。 又，受檢氣體可爲天然氣或液化石油氣，亦可爲其他氣體 ，但當然須視受檢氣體之種類而採用不同之氣體感測器。 電池部15在本例中係供應3伏特之電源，將電力供 應至圖1所示之整體電路。換言之，將電池部15產生之 電壓，供應至感測器系統電路，亦即由氣體感測器1 1內 的加熱器電阻1 1 b與感測器電阻1 1 a、負載電阻R、開關 SW1、SW2等所構成之氣體檢測手段。此外，控制電路部 12之電力亦由電池部15供應。 控制電路部12係爲控制瓦斯警報器10整體動作之微 電腦（CPU等），其執行未圖示之內部記億體所預先存儲 之應用程式，以實施上述控制處理，或後述圖3所示之流 程處理等。 控制電路部12具有輸出端子0UT1、0UT2'輸入端 子ADI，AD2等各端子。輸出端子OUT1連接至開關SW1 之基極，藉由輸出端子OUT 1之輸出信號，來控制開關 SW1爲ΟΝ/OFF。輸出端子OUT2連接至開關SW2之基 極，藉由輸出端子OUT2之輸出信號，來控制開關SW2爲 ON/ OFF。又，輸入端子ADI、AD2有時又特別稱之爲 AD轉換輸入端子ADI、AD2等，理由後述。 以上述規定之驅動周期進行瓦斯洩漏檢測處理時，控 制電路部12會藉由輸出端子OUT 1、OUT2之輸出信號， -10- 201246138 而將開關SW1及開關SW2切換爲ON，將電力供應至由氣 體感測器1 1 (加熱器電阻1 1 b、感測器電阻1 1 a )、負載 電阻R所構成之感測器系統電路，使其動作。 又如圖所示，開關SW2、感測器電阻1 1 a、負載電阻 R所串聯而成之串聯電路，與開關SW 1、加熱器電阻1 1 b 串聯而成之串聯電路，兩者並聯設置。針對各串聯電路， 施加來自上述電池部15之電源電壓（3V)。 此外，感測器電阻1 1 a與負載電阻R之間的電壓値 VI，介由AD (類比-數位）轉換輸入端子AD1，而輸入至 控制電路部1 2 »負載電阻R之電阻値可爲任意値，但爲 一固定値，當感測器電阻1 1 a之電阻値變化時，電壓値 V1亦會變化。也就是說，電壓値V1與感測器電阻1 1 a的 電阻値相當。 藉此，控制電路部12介由輸入端子AD1，檢測氣體 感測器1 1之感測器輸出（電壓値V1，或感測器電阻1 1 a 之電阻値），例如判定感測器輸出是否超過規定之氣體濃 度（後述之第1基準濃度（警報標準））所對應之値，據 以進行瓦斯洩漏檢測。該方式大致與習知方式相同，但在 本例中另設定了第2基準濃度，亦即較第1基準濃度更低 之閾値，藉此處理感測器驅動周期之變更等。詳如後述。 又，所用之AD轉換輸入端子ADI，AD2，不只包含 輸入端子，尙包含將輸入端子所輸入之類比信號（電壓値 V1等）轉換爲數位値之功能（AD (類比-數位）轉換器） 。因此，控制電路部12介由輸入端子AD1，而輸入電壓 -11 - 201246138 値V1之數位値。 笤報部13具備瞥報音輸出部13a、警報顯示部13b、 外部啓報輸出部1 3 c。啓報音輸出部1 3 a爲發出警報音等 聲響之部分，例如由揚聲器或蜂鳴器等所構成。警報音輸 出部1 3 a依據控制電路部1 2之控制，以語音訊息或電子 音，通報瓦斯洩漏狀態。普報顯示部13b由LED(發光二 極體）等所構成，控制電路部12在警報時，會令LED閃 爍或發亮以利用LED顯示瞀報狀態，通報瓦斯洩漏狀態 。此外，控制電路部12在警報時，亦可介由外部瞀報輸 出部13c，對氣體錶或中央監控面板等外部機器輸出瞢報 信號。 又，周圍溫度檢測部14因與本發明無關，故省略詳 細說明’其構造爲介由AD轉換輸入端子AD2，將周圍溫 度値輸入至控制電路部1 2，使控制電路部1 2依據周圍溫 度，執行氣體濃度之溫度修正計算。 在此利用圖2之時序圖，說明本實施形態之感測器驅 動情形。 控制電路部1 2是以感測器驅動周期Ta、感測器驅動 時間（相當於上述脈衝通電時間）Tb，來驅動氣體感測器 1 1 ’於每一周期Ta進行氣體檢測。在本方法中，該感測 器驅動周期Ta可能會暫時變更。詳如後述。 本實施形態中，正常情形下，舉例來說，以感測器驅 動周期Ta = 45秒、感測器驅動時間Tb = 1 00ms (毫秒） ，來驅動氣體感測器1 1。具體而言，係依據控制電路部 -12- 201246138 1 2內部之計時器（未圖示）之控制，於每個感測器驅動周 期T a執行下述動作。 於每個上述感測器驅動周期Ta之感測器驅動時間點 ’控制電路部12藉由輸出端子OUT1、OUT2之輸出信號 ’將開關SW1與開關SW2切換爲ON，對氣體感測器11 內的加熱器電阻1 1 b與感測器電阻1 1 a施加電源電壓。加 熱器電阻1 1 b被施加電漉電壓後，例如會加熱至4001等 〇 控制電路部1 2，當從上述感測器驅動時間點經過 100ms後（例如以內部計時器來判定是否經過100ms)， 會從AD1端子讀取氣體感測器輸出電壓V1。控制電路部 12接著將讀取之感測器輸出電壓VI換算爲氣體濃度，將 該氣體濃度與規定之閾値（警報標準）比較，判定是否超 過規定之氣體濃度。 又，將感測器輸出電壓VI換算爲氣體濃度之處理， 係爲既知之普遍手法，在此不特別說明。另，上述換算而 得之氣體濃度（所測定之氣體濃度）與規定之簪報標準相 比較之處理，同樣爲既知技術，但本方法中更追加了另一 閾値。換言之，習知之閾値僅有1種’而本方法中則設定 了 2種閩値。 亦即在本方法中，如圖2所示’設定了第丨基準濃度 (第1閩値）及第2基準濃度（第2閾値）等2種閾値。 第1基準濃度，例如可視爲與上述警報標準相當之濃度， 當上述換算而得之氣體濃度（所測定之氣體濃度）超過第 -13- 201246138 1基準濃度時，便發出瓦斯洩漏簦報。另一方面，第2基 準濃度係爲較第1基準濃度更低之閾値（第1基準濃度> 第2基準濃度）。當瓦斯洩漏發生時（特別是氣體濃度較 濃時），上述測定氣體濃度，基本上會先超過第2閩値， 而後再超過第1閾値。 而本方法中，當測定氣體濃度超過第2閾値時（且未 超過第1閾値時），會改變感測器驅動周期Ta。其會變 得比上述正常情形下之感測器驅動周期（=45秒）更短， 在本例中例如Ta = 2 0秒，但當然不以本例爲限。之後， 當測定氣體濃度超過第1閩値時，則與習知方式相同，控 制上述啓報部1 3，進行瓦斯洩漏通報動作。 在此，圖2的「氣體濃度」欄中，揭示了上述第1基 準濃度、第2基準濃度、測定氣體濃度之具體例。而在「 感測器驅動」欄、「普報顯示」欄中，則揭示了因應「氣 體濃度」欄之例之感測器驅動時間點、通報/發報時間點 〇 圖2所示之例中，從第1至第3次爲止之氣體檢測， 因測定氣體濃度並未超過第2基準濃度（第2閩値），故 判定周圍並無瓦斯而不發出警報，感測器驅動周期Ta亦 維持在45秒。 而第4次之氣體檢測，因測定氣體濃度超過了第2基 準濃度，故判定周圍有瓦斯，縮短感測器驅動周期Ta ( 本例中將正常之45秒周期變更爲20秒周期）。又，在此 情形下，因測定氣體濃度未達警報標準濃度（即第1基準 -14 - 201246138 濃度），故不發出瓦斯洩漏警報。 由於感測器驅動周期Ta已變更（周期縮短），第5 次之氣體檢測，係在第4次氣體檢測的20秒後實施，但 因“測定氣體濃度超過第2基準濃度但爲第1基準濃度以 下，且檢測次數（=第2次）未達規定次數（5次）”， 故維持感測器驅動周期Ta=20秒。又，當檢測次數爲規 定次數（5回）以上時，其處理後述。 需注意的是’上述“檢測次數未達規定次數”之條件 ，並非必要條件。因此舉例來說，只要持續滿足上述“測 定氣體濃度超過第2基準濃度但爲第1基準濃度以下”之 條件，則可不限檢測次數，維持感測器驅動周期T a = 2 0 秒。 另，第6次之氣體檢測’因測定氣體濃度上昇且超過 警報標準濃度（第1基準濃度），故發出語音發佈瓦斯洩 漏警報，或以LED進行警報顯示。此外，一旦進行瓦斯 洩漏警報後，因已達到及早氣體檢測之目的，故其後感測 器驅動周期Ta會恢復正常的45秒周期，繼續進行後續之 氣體檢測（第7次以後之氣體檢測）。需注意的是，此亦 非必要條件。因此舉例來說，即時於警報發佈或警報顯示 等之後，亦可不恢復45秒周期，而維持感測器驅動周期 T a = 2 0 秒。 如上所述，本例之瓦斯警報器1 0於正常情形下，檢 測動作之周期較長（例如4 5秒周期動作），可抑制電池 耗電量以省電，同時在遇到氣體濃度急遽上昇之情形時， -15- 201246138 檢測動作之周期變爲較短（例如2 0秒周期動作），可及 早檢測出瓦斯洩漏，不會有檢測延遲，故能提供高可靠性 之瓦斯瞢報器。 另’圖2之時序圖雖未揭示，但亦可如下述方式動作 〇 亦即，基本上同上所述，當測定氣體濃度超過第2基 準濃度後’以20秒周期實施本處理（瓦斯洩漏判定）， 規定次數（本例中爲5次）連續滿足「第2基準濃度<所 測定之氣體濃度<第1基準濃度」（圖3之步驟S2爲NO ’步驟S3爲YES)時，令感測器驅動周期Ta恢復正常之 45秒周期較爲理想。換言之在該情形下，周圍雖有瓦斯， 但經過規定時間後仍未超過第1基準濃度，故可判斷氣體 濃度上昇緩慢，並不具危險性，因此停止以2 0秒周期作 爲感測器驅動周期，而恢復正常之感測器驅動周期45秒 周期，以抑制無謂的電力消耗。 又，上述規定次數或較短周期之感測器驅動周期値， 可視欲檢測之氣體濃度變化而適當決定最佳値，並不限於 上述値（5次或20秒）。 圖3爲實施形態一例中，決定感測器驅動周期之處理 流程圖。該流程圖之處理，係藉由圖1之控制電路部12 ( 微電腦等），於每個Ta周期執行感測器驅動時反覆進行 ，例如於感測器脈衝驅動之結束時間點（1 00ms經過時等 )實施。此外，所驅動之感測器當然爲上述氣體感測器1 1 -16- 201246138 首先，圖1之控制電路部12基於其未圖示之內部計 時器之控制，以感測器驅動周期Ta於每次感測器驅動時 間Tb進行感測器驅動，感測器驅動結束時，介由AD轉 換輸入端子AD 1，讀取氣體感測器11之感測器輸出電壓 VI。控制電路部12接著依據所讀取之感測器輸出電壓VI ，算出氣體濃度（步驟S1)。又，承上所述，本例中正 常情形之Ta爲45秒，而Tb則固定爲100ms。 接著，判定所算出之目前氣體濃度（測定氣體濃度） ，是否超過警報標準濃度，亦即第1基準濃度（第1閩値 )(測定氣體濃度 > 第1基準濃度？）（步驟S2)。 若測定氣體濃度超過第1基準濃度（步驟S2，YES )， 則強制將短周期檢測計次値設爲‘ 5 ’（步驟S 1 0 )，並且將 感測器驅動周期Ta設定爲正常周期（本例中爲45秒）（ 步驟S11)，進行規定之警報處理（步驟S12)後，結束 本處理。又，步驟S12爲上述警報部13所發出之警報處 理。 在此，本方法中，當處於「第2基準濃度<所測定之 氣體濃度<第1基準濃度」狀態時，會以較正常驅動周期 (本例中爲45秒）更短之驅動周期（本例中爲20秒）來 驅動感測器；所謂的短周期檢測計次，是針對以20秒周 期驅動感測器之次數予以計數。當該計數値達規定値（本 例中爲ς 5 ’）以上時，令感測器驅動周期τ a從短周期（2 〇 秒）恢復至正常驅動周期（4 5秒）（後述步驟S 4爲γ e S ，執行S 9 )。 -17- 201246138 但當測定氣體濃度超過第1基準濃度，則無論目前計 數値爲何，皆強制將短周期檢測計次設爲‘ 5 ’。藉此，當測 定氣體濃度超過第1基準濃度時，會停止以短周期來驅動 感測器》這在圖3例中，例如測定氣體濃度超過第1基準 濃度後，即使因某些變動而再次回到「第2基準濃度 < 所 測定之氣體濃度 < 第1基準濃度」之狀態，因滿足後述步 驟S4判定爲YES，故仍會維持在正常驅動周期（45秒） 。但並非限於本例。 如上所述，本例中盡可能減少以短周期驅動感測器之 次數，故可將增加之消耗電流抑制在最小限度，同時及早 發出瓦斯洩漏瞢報。 另一方面，當測定氣體濃度爲第1基準濃度以下時（ 步驟S 2，Ν Ο )，下一步則判定測定氣體濃度是否超過比 第1基準濃度閩値還低之第2基準濃度（第2閾値）（測 定氣體濃度 >第2基準濃度？）（步驟S3)。 若測定氣體濃度爲第2基準濃度以下（步驟S3，NO )，則判定周圍無瓦斯，清除短周期檢測計次（將計次値 設爲初始値=1)(步驟S8)，設定感測器驅動周期Ta 爲正常驅動之45秒（步驟S9)，並且在不發出昝報之狀 態下（若爲啓報中則解除警報後）（步驟S7 )，結束本 處理。 此外，測定氣體濃度爲第1基準濃度以下，且超過第 2基準濃度時（S2爲NO，S3爲YES )，首先會判定短周 期檢測計次是否達5次以上（步驟S4 ) » -18- 201246138 若短周期檢測計次達5次以上（步驟S4，YES)，亦 即以短周期（20秒）驅動感測器之次數已達規定次數時， 會令感測器驅動周期Ta恢復正常驅動之45秒周期（步驟 S9 )。前文中已敍明其理由，因以短周期檢測之次數已經 結束，不再需要。 另一方面，若短周期檢測計次未滿5次（步驟S4，NO )，則設定感測器驅動周期爲20秒（已爲20秒時則維持 :繼續以短周期進行檢測）（步驟S 5 )，加算短周期檢 測計次（步驟S 6 )，執行上述步驟S 7之處理後，結束本 處理。 如以上所說明的，本實施形態中，當疑似瓦斯洩漏之 狀況發生時（測定氣體濃度 > 第2基準濃度時），則將正 常之感測器驅動周期（45秒）切換成較短之感測器驅動周 期（20秒），以較正常情況更短之感測器驅動間隔來進行 氣體檢測，因此可抑制電池耗電量達成省電，同時在氣體 濃度急遽增加的情形下，也能及早檢測出瓦斯洩漏並發出 警報，不會產生檢測延遲。 特別是針對「在高濃度（12500ppm )瓦斯環境實驗中 ，需在瓦斯洩漏60秒以內檢測並發出警報」之要求，不 僅可予達成，尙能抑制電池耗電量達成省電（後續參照圖 4、圖5加以說明）。 此外，本實施形態中，藉由上述S10與S11，或S4 與S 9之處理，對短周期（2 0秒）之感測器驅動次數加上 限制條件，可抑制無謂的電力消耗。換言之’在測定氣體 -19- 201246138 濃度超過第1基準濃度後（發出警報後），令感測器驅動 周期Ta恢復正常驅動之45秒周期，可抑制無謂的電力消 耗》又或者，當開始處於以短周期（20秒）驅動感測器之 狀態，若測定氣體濃度未超過第1基準濃度，而驅動次數 (檢測次數）已達規定次數時，則令感測器驅動周期Ta 從短周期（20秒）恢復至正常驅動周期（45秒），可抑 制無謂的電力消耗》 接著參照圖4、圖5，揭示以本實施例執行動作之一 例。 圖4爲習知之瓦斯瞢報器曝露於高濃度（1 2500PPm) 瓦斯中時，氣體感測器11內氣體濃度變化與基準濃度之 關係。圖5爲置換成本例瓦斯普報器10時，氣體濃度變 化（條件同圖4)與2種基準濃度之關係》 氣體感測器11內之氣體濃度，會因瞀報器10本體之 感測器室構造、氣體感測器構造、或爲過濾其他氣體而設 置之過濾器結構而有所影響，無法即時與周圍氣體濃度同 步，而會逐漸接近周圍氣體濃度。將瓦斯昝報器1〇置放 於高濃度瓦斯中，則如圖所示，氣體感測器1 1內之氣體 濃度會逐漸上昇，接近周圍之氣體濃度。又，將瓦斯啓報 器1 〇置放於高濃度瓦斯中的時間點，可視爲瓦斯洩漏發 生之時間點》 又，本例中如圖所示，從瓦斯洩漏開始發生經過34 秒後，氣體感測器1 1內之氣體濃度（即測得之氣體濃度 )，應超過第1基準濃度（警報標準）。 -20- 201246138 上述條件下’遇氣體濃度急遽上昇時，必須在1分鐘 以內發出瓦斯洩漏警報。但若僅以正常之45秒周期來驅 動感測器’依感測器驅動時間點的不同，可能無法於瓦斯 洩漏發生後1分鐘以內發出瓦斯洩漏警報。具體而言，若 感測器驅動時間點在圖4中T2區間時，便無法在1分鐘 以內發出瓦斯洩漏警報。以下詳細說明之。 首先’考量以正常之感測器驅動周期（=45秒），而 感測器驅動時間點落在圖4中T1區間內（〇〜1 5秒）之 情形，在T1區間中，因未超過第1基準濃度，不會發出 瓦斯洩漏警報。而因感測器驅動周期爲45秒周期，下— 次感測器驅動時間點爲本次驅動後4 5秒後，即下—次感 測器驅動時間點落在圖4中T4區間內（45〜60秒）。在 T4區間中，因氣體濃度已超過第1基準濃度，會發出瓦 斯洩漏警報。是故，即便在正常之感測器驅動周期（45秒 )情形下，只要感測器驅動時間點落在T1區間內，那麼 下一次驅動時間點便會在瓦斯洩漏發生後的60秒以內， 且下一次驅動時間點可檢測出超過第1基準濃度之氣體濃 度，故可在1分鐘以內發出瓦斯洩漏警報。 接下來，考量以正常之感測器驅動周期（=45秒）， 而感測器驅動時間點落在圖4中T3區間內（34〜45秒） 之情形，若在該時間點進行氣體檢測，因氣體感測器11 內之氣體濃度已超過第1基準濃度’故可即時發出瓦斯洩 漏警報。 最後，考量以正常之感測器驅動周期（=45秒），而 -21 - 201246138 感測器驅動時間點落在圖4中T2區間內（1 5〜34秒）之 情形，在該時間點氣體濃度尙未超過第1基準濃度，故不 發出瓦斯洩漏昝報。而若繼續維持感測器驅動周期爲45 秒，那麼下一次感測器驅動時間點會落在T 5 ( 6 0〜7 9秒 )，在圖例中濃度已超過約6000ppm (當然，此時氣體濃 度早已超過第1基準濃度），雖會發出瓦斯洩漏警報，但 已在瓦斯洩漏發生超過60秒後才發出瓦斯洩漏瞀報，無 法滿足在1分鐘以內發出瞢報之要求》 另一方面，若將本例之瓦斯警報銮10應用於上述實 驗條件中，則如圖5所示，無論在任何情形下皆可於1分 鐘以內發出瓦斯洩漏θ報。又，使用本例之瓦斯替報器10 時，若感測器驅動時間點落在上述Τ1或Τ3區間內，當然 亦與習知發明相同，可在1分鐘以內發出瓦斯洩漏警報。 而使用本例之瓦斯啓報器1 0時，即使感測器驅動時間點 落在上述T2區間內，仍可在1分鐘以內發出瓦斯洩漏警 報。 又，圖5所示之例中，所量測之氣體濃度變化與圖4 之例相同，θ報標準（第1基準濃度）亦與圖4之例相同 。而採用本方法之瓦斯昝報器10，同時設定了較警報標準 (第1基準濃度）更低之閾値（第2基準濃度），圖5所 示之例中，從瓦斯洩漏開始發生經過1 5秒後（Τ2區間的 起始），計測氣體濃度超過第2基準濃度。 以下循圖5所示之例，說明感測器驅動時間點落在上 述Τ2區間內之情形。 -22- 201246138 首先與習知發明相同，考量以正常之感測器驅動周期 (=45秒），而感測器驅動時間點落在T2區間內之情形 ，因計測氣體濃度超過第2基準濃度，此時，感測器驅動 周期會從上述正常周期（45秒周期）變更爲短周期（20 秒周期）。而因檢測周期（驅動周期）變爲20秒，下一 次感測器驅動時間點會落在圖5的T 6區間內（3 5〜5 4秒 )。是故，在下一次感測器驅動時間點，測定氣體濃度會 超過第1基準濃度，故可於1分鐘以內發出瓦斯洩漏警報 〇 如上所述，採用本例之瓦斯警報器10之感測器驅動 方法，正常情形爲45秒周期，驅動氣體感測器不須消耗 額外電力，可減低電池使用量。而僅在有瓦斯洩漏疑慮之 情形下（超過第2基準濃度時），將正常之驅動周期（45 秒周期）切換成較短之驅動周期（20秒周期），令其較正 常情形下以更短之感測器驅動間隔，來進行氣體檢測。藉 此，可將增加之消耗電流抑制在最小限度，同時及早發出 瓦斯洩漏警報。特別是在要求於1分鐘以內發出瓦斯洩漏 警報之狀態下，可抑制電力消耗，同時確實在1分鐘以內 發出瓦斯洩漏警報，可提供可靠性高之警報器。 又，圖4、圖5所示甲烷氣體濃度與經過時間之關係 僅爲一例，氣體濃度與經過時間之關係，會因警報器本體 之感測器室構造、氣體感測器構造、氣體感測器之過濾器 種類等而有所變異，設計者可視上述關係，適當決定較正 常情形更短之驅動周期時間，或短周期驅動之次數。 -23- 201246138 在此，圖6揭示了氣體濃度緩慢增加時，感測器驅動 之時序圖。 如圖所示，在該情形下，從量測氣體濃度超過第2基 準濃度開始起算，因量測已達5次（短周期檢測計次g 5 )而仍未超過第1基準濃度，故會恢復45秒周期，其後 在超過第1基準濃度之時間點會發出警報。又，上述在60 秒以內之瓦斯洩漏檢測，其前提條件爲高濃度（1 2500ppm )瓦斯環境實驗，與圖6所示之例（氣體濃度緩慢增加） 無關。因此在圖6之例中，雖未進行60秒以內之瓦斯洩 漏檢測實驗，但不會構成問題。 此外，圖7爲不執行步驟S10、S11之變形例中，感 測器驅動之時序圖。 換言之’圖3所示之處理例僅爲一例，不以本例爲限 。例如不執行S 1 0、S 1 1亦可。在該情形下，S 1 0、S 1 1雖 不執行，但S4、S5、S6、S9則執行相同處理。也就是說 ’亦可在超過第1基準濃度後，不立即恢復45秒周期， 而是令量測氣體濃度從超過第2基準濃度開始起算，以短 周期（20秒）驅動規定次數（短周期檢測計次=5)。換 言之’在超過第2基準濃度的情形下，其後無論是否超過 第1基準濃度’一律令其以短周期（20秒）驅動規定之複 數次（短周期檢測計次=5 )。 以上揭不者爲變形例之一例，亦可有其他變形例。無 論如何，本發明並非限定於上述圖1〜圖5所示之一種實 施形態。 -24- 201246138 綜上所述’本發明之警報器於正常情形下，用於氣體 檢測之脈衝通電驅動周期較長，以減低電池使用量；且受 檢氣體之氣體濃度超過未滿警報標準之規定濃度（第2基 準濃度）時，會縮短感測器驅動周期，以及早達成氣體檢 測。又，亦可限制感測器驅動周期縮短次數，爲規定之複 數次。此外，氣體濃度超過警報標準後，亦可立即令感測 器驅動周期恢復至原來周期。藉此，可將增加之消耗電流 抑制在最小限度，同時及早發出瓦斯洩漏警報。 針對氣體濃度急遽變化時，不會發生檢測延遲，而能 在規定之氣體濃度下發出警報，可提供可靠性高之瓦斯警 報器。 驅動氣體感測器不須消耗額外電力，可減低電池使用 量，進而減少電池數量，降低成本，使機器更小、更輕。 又，上述控制電路部12執行上述應用程式等，藉此 ，本例之瓦斯警報器10亦可具備下述各種功能部。 換言之，上述瓦斯警報器10係以電池作爲電源之電 池式瓦斯警報器，依據氣體感測器之輸出來進行瓦斯洩漏 檢測，該氣體感測器會因應受檢氣體之氣體濃度而改變電 性；該電池式瓦斯警報器，具備以下各種功能部。 首先，具有感測器驅動功能部，係以任意之驅動周期 ，透過脈衝通電而驅動氣體感測器之功能部，正常情形下 會以第1驅動周期來驅動氣體感測器。 此外，具有氣體濃度算出功能部，依據該感測器驅動 時氣體感測器之輸出，算出氣體濃度；及瞢報功能部，當 -25- 201246138 該算出之氣體濃度超過規定之第1閾値，發出瞀報。 尙具有驅動周期變更功能部，判定氣體濃度算出手段 所算出之氣體濃度（測定氣體濃度），是否超過較第1閩 値更低之第2閩値，若氣體濃度超過該第2閩値，則令感 測器驅動功能部，以較第1驅動周期更短之第2驅動周期 ，來驅動氣體感測器。 此外，例如亦可使上述驅動周期變更功能部，當以第 2驅動周期驅動氣體感測器之次數，已達預先設定之規定 次數時，或當測定氣體濃度在超過第1閩値之前，以第2 驅動周期驅動氣體感測器之次數，已達預先設定之規定次 數時，令感測器驅動功能部之驅動周期，恢復成第1驅動 周期。 此外，例如亦可使上述驅動周期變更功能部，當測定 氣體濃度超過第1閾値時，令感測器驅動功能部之驅動周 期，恢復成第1驅動周期。 使用本發明之電池式瓦斯昝報器及控制裝置等，針對 以電池做爲電源之電池式瓦斯昝報器，可抑制電池消耗以 省電，同時遇氣體濃度急遽上昇時，亦可及早發出瓦斯洩 漏啓報，不會有檢測延遲。 【圖式簡單說明】 〔圖1〕 本發明瓦斯普報器實施形態一例之構成圖。 〔圖2〕 -26- 201246138 實施形態一例之感測器驅動時序圖。 〔圖3〕 實施形態一例中，判定感測器驅動周期之處理流程圖 〔圖4〕 氣體濃度與經過時間之關係圖。 〔圖5〕 實施形態一例中，氣體濃度與經過時間之關係圖。 〔圖6〕 氣體濃度緩慢增加時，感測器驅動之時序圖。 〔圖7〕 不執行步驟s 1 0，S 1 1之變形例中，感測器驅動之時 序圖。 〔圖8〕 習知電池式瓦斯警報器之感測器驅動時間點說明圖。 【主要元件符號說明】 1 〇 :瓦斯警報器 1 1 :氣體感測器 1 2 :控制電路部 1 3 :警報部 1 4 :周圍溫度檢測部 1 5 :電池部 1 1 a :感測器電阻 -27- 201246138 1 1 b :加熱器電阻 1 3 a :替報音輸出部 13b :警報顯示部 1 3 c :外部曾報輸出部 R :負載電阻 SW1、SW2 :電晶體開關 ADI、AD2 :輸入端子 OUT1、OUT2 :輸出端子 -28201246138 VI. Description of the Invention: [Technical Field] The present invention relates to a gas leakage alarm for detecting flammable gas such as natural gas or liquefied petroleum gas leaking from a gas appliance or a gas pipeline, and issuing an alarm, particularly using a battery as a power source Battery type gas alarm. [Prior Art] A gas alarm that detects a gas leak in a gas appliance or a gas pipeline and issues an alarm with a voice or a buzzer to notify the gas user that there is a gas leak is widely known. The gas alarm detects the gas to be inspected by a gas detecting element such as a gas sensor, and when the gas concentration of the gas to be inspected exceeds a predetermined gas concentration, an alarm is generated by an alarm sound or an alarm display. In the gas alarm, a gas sensor is used to detect a gas such as natural gas or liquefied petroleum gas. The gas sensor has, for example, a heater resistance and a sensor resistance. The sensor resistance reacts with the gas to be tested and changes its resistance 値. The resistance 値 of the sensor resistance is measured by the heated heater resistance for gas detection. For example, a voltage is applied to the heater resistance of the gas sensor, the heater temperature is at a predetermined temperature, such as 400 ° C, and the resistance of the sensor resistor is measured (actually, the voltage indicated by the resistor 値, etc.) Change the gas to perform gas detection. In order to make the temperature of the heater of the gas sensor reach the specified temperature, the driving method may be a method of applying a DC voltage or a method of applying a pulse voltage, but -5 - 201246138 in a battery-driven battery gas detector, In order to save power, a method of pulsing a heater by a predetermined driving cycle is often employed (Patent Document 1 and Patent Document 2). Fig. 8 is an example of driving a sensor by pulse energization. The sensor drive period is 45 seconds, and the gas sensor is energized for 10 ms in each cycle, and gas detection is performed at the time point when the pulse energization ends. In order to save power, the pulse energization time (the time when the voltage is applied to the gas sensor, in this case, 1 〇〇ms) is shortened, so that the gas detection can be completed in a short time, and the driving cycle is lengthened to save power. The sensor is a gas detector. In a high-concentration (1 2500 ppm) gas environment experiment, the gas leak must be detected within 60 seconds after the gas leak occurs, and a report is issued (Patent Document 3). In this regard, the battery-operated gas alarm device has a method of performing pulse energization at a predetermined driving cycle in order to save power as described above. However, this method only performs gas detection at a specified driving cycle time point, instead of performing gas detection at any time, so it is difficult to detect gas and report it within 60 seconds. In addition, due to the convenience of wire-free installation or miniaturization of the machine, there is a need for a battery-operated gas alarm, but when detecting the gas to be tested, the heater of the gas sensor must be heated to about 400 °C. This will consume a lot of power. Therefore, it is a problem to drive the sensor in a battery-saving manner during the effective period of the gas alarm for 5 years. [Patent Document 1] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. 2003-. In the gas alarm, the gas detection operation is performed only at the predetermined driving cycle time point, and the gas detection is not performed at any time (uninterrupted). Therefore, when the gas concentration rises sharply, it is difficult to detect it early in the detection time. Gas and an alarm. Patent Document 1, 2 does not consider this detection delay, and Patent Document 3 discloses an embodiment in which the pulse is driven in a 20 second cycle, but the battery consumption is very large. In order to solve the above problems, the driving period of the pulse energization can be shortened, and the time point of gas detection can be increased; however, when the gas sensor is energized, the temperature of the heater must be heated to about 400 ° C, requiring a large amount of power, and battery consumption. It will be very large (for example, changing the drive cycle from 45 seconds to 5 seconds, the gas sensor will consume 9 times more power). Therefore, for a battery type gas alarm, although it is desired to lengthen the driving period of the pulse energization as much as possible, if the driving period is too long, gas detection is not performed at a time point other than the driving period, which causes the gas detection to be delayed and lost. The original intention of issuing an early warning caused the alarm to be delayed and could not be issued while still in a safe state. (For example, if the drive cycle is changed from 45 seconds to 90 seconds, then the gas sensor will consume 1/2 of the power, but it will be detected every 90 seconds, if the gas concentration is 90 seconds. If there is a large increase in the inside, it may be detected after the gas concentration has exceeded the detected concentration, causing safety concerns.) Also, when the gas sensor detects the surrounding gas concentration, the internal gas is -7-201246138 The body concentration may be affected by the structure of the detector body, the structure of the gas sensor, or the filter structure provided for filtering other gases. It is not immediately synchronized with the ambient gas concentration, but is delayed compared to the surrounding gas concentration. Gradually approach the surrounding gas concentration. Therefore, when determining the drive cycle, it is not necessary to consider the drive cycle of the sensor, and it is not necessary to consider the gas concentration detection delay caused by the detector structure. The object of the present invention is to provide a highly reliable battery type gas detector and control device thereof, which is directed to a battery type gas detector using a battery as a power source, which can suppress battery power consumption and save power, and at the same time. When a gas leak is reported, there will be no delay in the detection of the detected gas. The gas detector of the invention is a battery type gas detector with a battery as a power source, and the gas leakage detection is performed according to the output of the gas sensor, and the gas sensor changes the electricity according to the gas concentration of the gas to be tested. The battery type gas detector has the following features: The sensor driving means is a means for driving the gas sensor by pulse energization in an arbitrary driving period, which is normally a driving cycle of driving the gas sensor; and a gas concentration calculating means for calculating a gas concentration based on an output of the gas sensor during the driving: and a general reporting means, wherein the calculated gas concentration exceeds a predetermined first threshold , issued θ report.尙 having a driving cycle changing means for determining whether the gas concentration calculated by the gas concentration calculating means exceeds a second enthalpy lower than the first threshold 闽値, and if the gas concentration exceeds the second threshold 则, the sensor is made The driving means drives the gas sensor with a second driving cycle shorter than the first driving cycle, -8 - 201246138, and detects and detects the leakage in the second and the second driving cycle. Alarm gas alarm 1 1. Control unit 1 5 1 body switch SW1 > With the above-described gas alarm of the present invention, in a normal case, a longer driving period (first driving period) is used to drive the gas to sense the surrounding gas. When the gas concentration exceeds the first level lower than the first one, the ambient gas is driven by the shorter period of the shorter driving period (second driving period). In this way, it is possible to suppress the power consumption of the battery to save power, and at the same time, when the gas concentration rises sharply, the detection delay of the gas search can be detected early. [Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a block diagram showing an embodiment of a gas alarm of the present invention. The gas alarm 1 in the figure is a gas detector for detecting gas or gas leaking gas, liquefied petroleum gas, etc., and emits a gas leak alarm, especially a battery type battery as a power source. The gas alarm device 10 includes a gas sensor circuit unit 1 2, an alarm unit 13 , an ambient temperature detecting unit 14 , electricity, and the like, and further includes a load resistor R, a transistor switch SW1, and an electric crystal SW2. Graphic circuit. Further, hereinafter, the transistor switch transistor switch SW2 will be briefly described as the switch SW1 and the switch SW2. The gas sensor 11 for detecting the gas to be inspected includes a sensor resistor 1 1 a for detecting the gas concentration, and a heater resistor 1 1 b for heating the same. As is well known, the resistance 値 of the sensor resistance 1 1 a varies according to the surrounding gas concentration 201246138 degrees. When the gas leakage detection process is performed in the driving cycle specified above, the heater resistance 1 1 b is heated to, for example, 400. °C, and measure the resistance 値 of the sensor resistance 1 1 a (or the voltage 値 corresponding to the resistance 値, etc.). Moreover, the gas to be tested may be natural gas or liquefied petroleum gas, or may be other gases, but of course, different gas sensors are used depending on the type of gas to be inspected. The battery unit 15 supplies a power supply of 3 volts in this example, and supplies power to the entire circuit shown in Fig. 1. In other words, the voltage generated by the battery unit 15 is supplied to the sensor system circuit, that is, the heater resistor 1 1 b in the gas sensor 1 1 and the sensor resistor 1 1 a, the load resistor R, and the switch SW1. , gas detection means composed of SW2, etc. Further, the electric power of the control circuit unit 12 is also supplied from the battery unit 15. The control circuit unit 12 is a microcomputer (such as a CPU) that controls the overall operation of the gas alarm 10, and executes an application stored in advance by an internal unit (not shown) to perform the above-described control processing, or as shown in FIG. Process processing, etc. The control circuit unit 12 has output terminals OUT1, OUT2' input terminals ADI, AD2 and the like. The output terminal OUT1 is connected to the base of the switch SW1, and the output signal of the output terminal OUT1 is used to control the switch SW1 to be ΟΝ/OFF. The output terminal OUT2 is connected to the base of the switch SW2, and the switch SW2 is controlled to be ON/OFF by the output signal of the output terminal OUT2. Further, the input terminals ADI and AD2 are sometimes referred to as AD conversion input terminals ADI, AD2, etc., for the reason described later. When the gas leak detection process is performed in the drive cycle specified above, the control circuit unit 12 switches the switch SW1 and the switch SW2 to ON by the output signals of the output terminals OUT 1 and OUT2, -10-201246138, and supplies power to the switch. A sensor system circuit composed of a gas sensor 1 1 (heater resistor 1 1 b, sensor resistance 1 1 a ) and a load resistor R is operated. As shown in the figure, a series circuit in which the switch SW2, the sensor resistance 1 1 a, and the load resistor R are connected in series, and a series circuit formed by connecting the switch SW 1 and the heater resistor 1 1 b in series are arranged in parallel. . A power supply voltage (3 V) from the battery unit 15 is applied to each series circuit. In addition, the voltage 値VI between the sensor resistor 1 1 a and the load resistor R is converted to the input terminal AD1 via AD (analog-digital), and the resistance 値 input to the control circuit portion 1 2 » load resistor R can be Any 値, but a fixed 値, when the resistance 値 of the sensor resistance 1 1 a changes, the voltage 値V1 also changes. That is, the voltage 値V1 is equivalent to the resistance 値 of the sensor resistance 1 1 a. Thereby, the control circuit unit 12 detects the sensor output of the gas sensor 1 (voltage 値V1, or the resistance 感 of the sensor resistance 1 1 a) via the input terminal AD1, for example, determines whether the sensor output is The gas leak detection is performed in accordance with the enthalpy corresponding to the predetermined gas concentration (the first reference concentration (alarm standard) to be described later). This method is basically the same as the conventional method. However, in this example, the second reference concentration, i.e., the threshold 更低 lower than the first reference concentration, is set, thereby changing the sensor driving cycle or the like. Details will be described later. Further, the AD conversion input terminals ADI, AD2 used include not only the input terminal but also the function of converting the analog signal (voltage 値 V1, etc.) input from the input terminal into a digital ( (AD (analog-digital) converter). Therefore, the control circuit unit 12 inputs the digital value 値 of the voltage -11 - 201246138 値V1 via the input terminal AD1. The report unit 13 includes a 瞥-voice output unit 13a, an alarm display unit 13b, and an external report output unit 13c. The announcement sound output unit 1 3 a is a portion that emits an alarm sound or the like, and is constituted by, for example, a speaker or a buzzer. The alarm sound output unit 1 3 a notifies the gas leak state by voice information or electronic sound in accordance with the control of the control circuit unit 12. The general report display unit 13b is constituted by an LED (Light Emitting Diode) or the like, and when the control circuit unit 12 is alerted, the LED is blinked or lit to display the alarm state by the LED, and the gas leakage state is notified. Further, when the alarm is generated by the control circuit unit 12, the external signal output unit 13c can output a signal to the external device such as a gas meter or a central monitoring panel. Further, since the ambient temperature detecting unit 14 is not related to the present invention, detailed description thereof is omitted. The configuration is such that the ambient temperature 値 is input to the control circuit unit 12 via the AD conversion input terminal AD2, and the control circuit unit 12 is caused by the ambient temperature. , Perform temperature correction calculation of gas concentration. Here, the sensor driving situation of this embodiment will be described using the timing chart of Fig. 2. The control circuit unit 12 drives the gas sensor 1 1 ' to perform gas detection at each cycle Ta with the sensor drive period Ta and the sensor drive time (corresponding to the above-described pulse energization time) Tb. In the method, the sensor driving period Ta may be temporarily changed. Details will be described later. In the present embodiment, in the normal case, for example, the gas sensor 11 is driven with a sensor driving period Ta = 45 seconds and a sensor driving time Tb = 1 00 ms (msec). Specifically, the following operation is performed for each sensor driving period T a in accordance with the control of a timer (not shown) inside the control circuit unit -12-201246138 1 2 . In the sensor driving time point of each of the above-described sensor driving periods Ta, the control circuit unit 12 switches the switch SW1 and the switch SW2 to ON by the output signals of the output terminals OUT1 and OUT2, and is in the gas sensor 11 The heater resistor 1 1 b and the sensor resistor 1 1 a apply a supply voltage. After the heater resistor 1 1 b is applied with the power-on voltage, for example, it is heated to 4001 or the like, and the control circuit unit 1 2, after 100 ms elapses from the above-mentioned sensor driving time (for example, whether it is 100 ms after an internal timer) , the gas sensor output voltage V1 is read from the AD1 terminal. The control circuit unit 12 then converts the read sensor output voltage VI into a gas concentration, and compares the gas concentration with a predetermined threshold 警报 (alarm standard) to determine whether or not the predetermined gas concentration is exceeded. Further, the process of converting the sensor output voltage VI into the gas concentration is a well-known method, and is not particularly described herein. Further, the above-described conversion of the gas concentration (measured gas concentration) compared with the predetermined standard of reporting is also a known technique, but another threshold is added to the method. In other words, there is only one type of threshold threshold in the prior art, and two types of defects are set in the method. In other words, in the present method, as shown in Fig. 2, two kinds of thresholds, such as the second reference concentration (first 闽値) and the second reference concentration (second threshold 设定), are set. The first reference concentration can be regarded as a concentration corresponding to the above-mentioned alarm standard. When the gas concentration (measured gas concentration) obtained by the above conversion exceeds the reference concentration of the -13 - 201246138 1 , a gas leak report is issued. On the other hand, the second reference concentration is a threshold 値 (first reference concentration > second reference concentration) lower than the first reference concentration. When a gas leak occurs (especially when the gas concentration is high), the measured gas concentration will basically exceed the second enthalpy and then exceed the first threshold enthalpy. In the present method, when the measured gas concentration exceeds the second threshold (and does not exceed the first threshold), the sensor driving period Ta is changed. It will become shorter than the sensor drive period (= 45 seconds) in the normal case described above, for example, Ta = 20 seconds in this example, but of course not limited to this example. Thereafter, when the measured gas concentration exceeds the first enthalpy, the above-described priming unit 13 is controlled to perform the gas leak notification operation in the same manner as the conventional method. Here, a specific example of the first reference concentration, the second reference concentration, and the measured gas concentration is disclosed in the "Gas concentration" column of Fig. 2 . In the "Sensor Drive" column and the "General Report" column, the sensor drive time point and the notification/report time point in the example of the "Gas Concentration" column are revealed. In the gas detection from the first to the third time, since the measured gas concentration does not exceed the second reference concentration (second 闽値), it is determined that there is no gas around the alarm and the alarm is not issued, and the sensor drive period Ta is maintained. In 45 seconds. On the fourth gas detection, since the measured gas concentration exceeds the second reference concentration, it is determined that there is gas around, and the sensor drive period Ta is shortened (in this example, the normal 45 second cycle is changed to the 20 second cycle). Further, in this case, since the measured gas concentration does not reach the alarm standard concentration (i.e., the first reference -14 - 201246138 concentration), the gas leak alarm is not issued. Since the sensor drive cycle Ta has been changed (the cycle is shortened), the fifth gas detection is performed 20 seconds after the fourth gas detection, but the measurement gas concentration exceeds the second reference concentration but is the first reference. When the concentration is below and the number of detections (= second time) is less than the predetermined number of times (5 times), the sensor drive period Ta = 20 seconds is maintained. Further, when the number of detections is equal to or greater than the predetermined number of times (5 times), the processing will be described later. It should be noted that the above conditions of "the number of detections does not reach the specified number of times" are not necessary. For example, as long as the condition that the "measured gas concentration exceeds the second reference concentration but is equal to or lower than the first reference concentration" is continuously satisfied, the number of detections can be unlimited, and the sensor drive period T a = 2 0 seconds can be maintained. In addition, since the gas detection of the sixth time has risen and exceeds the alarm standard concentration (first reference concentration), a gas emission alarm is issued or an alarm is displayed by LED. In addition, once the gas leakage alarm is performed, since the purpose of early gas detection has been achieved, the subsequent sensor driving period Ta will return to the normal 45 second period, and the subsequent gas detection will continue (the gas detection after the seventh time). . It should be noted that this is not a requirement. Therefore, for example, after the alarm is issued or the alarm is displayed, the 45 second period may not be restored, and the sensor driving period T a = 2 0 seconds is maintained. As described above, in the normal case, the gas alarm 10 of the present example has a long period of detection operation (for example, a 45-second periodic operation), which can suppress battery power consumption to save power, and at the same time, the gas concentration is rapidly increased. In the case of -15-201246138, the period of the detection operation becomes shorter (for example, the 20-second periodic operation), the gas leakage can be detected early, and there is no detection delay, so that a high-reliability gas detector can be provided. The timing chart of FIG. 2 is not disclosed, but may be operated as follows. Basically, when the measured gas concentration exceeds the second reference concentration, the process is performed in a 20 second cycle (gas leakage determination). ), the specified number of times (5 times in this example) continuously satisfies the "second reference concentration" <measured gas concentration When the first reference concentration (step S2 in Fig. 3 is NO), the step S3 is YES), the period in which the sensor drive period Ta returns to normal 45 seconds is preferable. In other words, in this case, although there is gas around, but the first reference concentration has not been exceeded after a predetermined period of time, it can be judged that the gas concentration rises slowly and is not dangerous, so the cycle of 20 seconds is stopped as the sensor drive period. The normal sensor drive cycle is resumed for a period of 45 seconds to suppress unnecessary power consumption. Further, the sensor driving period 规定 of the predetermined number of times or the shorter period is appropriately determined depending on the change in the gas concentration to be detected, and is not limited to the above-described 値 (5 or 20 seconds). Fig. 3 is a flow chart showing the process of determining the sensor drive period in an example of the embodiment. The processing of the flowchart is repeated by the control circuit unit 12 (microcomputer or the like) of FIG. 1 when the sensor is driven for each Ta period, for example, at the end of the pulse driving of the sensor (1 00 ms passes). Time, etc.) implementation. In addition, the driven sensor is of course the above-mentioned gas sensor 1 1 -16 - 201246138. First, the control circuit unit 12 of FIG. 1 is based on the control of an internal timer (not shown), and the sensor driving period Ta is Each time the sensor driving time Tb is driven by the sensor, when the sensor driving ends, the sensor output voltage VI of the gas sensor 11 is read through the AD conversion input terminal AD1. The control circuit unit 12 then calculates the gas concentration based on the read sensor output voltage VI (step S1). Further, as stated above, in this example, the normal case Ta is 45 seconds, and the Tb is fixed at 100 ms. Next, it is determined whether or not the calculated current gas concentration (measurement gas concentration) exceeds the alarm standard concentration, that is, the first reference concentration (first 闽値) (measurement gas concentration > first reference concentration ???) (step S2). When the measured gas concentration exceeds the first reference concentration (YES in step S2), the short period detection count 値 is forcibly set to '5' (step S1 0), and the sensor drive period Ta is set to the normal period ( In this example, 45 seconds) (step S11), after the predetermined alarm processing (step S12) is performed, the processing is terminated. Further, step S12 is an alarm process issued by the alarm unit 13. Here, in the method, when the second reference concentration is <measured gas concentration In the <first reference concentration" state, the sensor is driven by a shorter driving period (20 seconds in this example) than the normal driving period (45 seconds in this example); the so-called short period detection count Is to count the number of times the sensor is driven in a 20 second period. When the count reaches the predetermined value (ς 5 ') in this example, the sensor drive period τ a is restored from the short period (2 〇 seconds) to the normal drive period (45 seconds) (step S 4 described later) For γ e S , S 9 ) is performed. -17- 201246138 However, when the measured gas concentration exceeds the first reference concentration, the short-cycle detection count is forcibly set to '5' regardless of the current count. Therefore, when the measured gas concentration exceeds the first reference concentration, the sensor is stopped to be driven in a short cycle. In the example of FIG. 3, for example, after the measured gas concentration exceeds the first reference concentration, even if some changes occur, Back to "2nd reference concentration < measured gas concentration The state of the <first reference concentration" is determined to be YES by satisfying the step S4 described later, and therefore remains in the normal drive period (45 seconds). But it is not limited to this example. As described above, in this example, the number of times the sensor is driven in a short period is minimized, so that the increased consumption current can be minimized, and the gas leakage is reported early. On the other hand, when the measured gas concentration is equal to or lower than the first reference concentration (step S2, Ν Ο ), the next step is to determine whether or not the measured gas concentration exceeds the second reference concentration lower than the first reference concentration ( (second Threshold 値) (measurement gas concentration > second reference concentration?) (step S3). When the measured gas concentration is equal to or lower than the second reference concentration (NO in step S3), it is determined that there is no gas in the surroundings, and the short cycle detection count is cleared (the count 値 is set to initial 値 = 1) (step S8), and the sensor is set. The drive period Ta is 45 seconds of the normal drive (step S9), and the process is terminated when the alarm is not issued (if the alarm is released in the case of the report) (step S7). Further, when the measured gas concentration is equal to or lower than the first reference concentration and exceeds the second reference concentration (S2 is NO, S3 is YES), it is first determined whether or not the short cycle detection count is five or more times (step S4) » -18- 201246138 If the short-cycle detection count reaches 5 times or more (step S4, YES), that is, when the number of times the sensor is driven in a short period (20 seconds) has reached the specified number of times, the sensor drive period Ta will resume normal drive. The 45 second period (step S9). The reason has been stated in the foregoing, as the number of short-cycle tests has ended and is no longer needed. On the other hand, if the short cycle detection count is less than 5 times (step S4, NO), the sensor drive cycle is set to 20 seconds (when 20 seconds is maintained: continue to detect in a short cycle) (step S 5), the short cycle detection count is added (step S6), and the processing of the above step S7 is executed, and the processing is terminated. As described above, in the present embodiment, when a situation in which a gas leak is suspected is generated (measurement gas concentration > second reference concentration), the normal sensor drive period (45 seconds) is switched to a shorter one. The sensor drive period (20 seconds), the gas detection is performed at a shorter sensor drive interval than normal, so that the battery power consumption can be suppressed to achieve power saving, and in the case where the gas concentration is rapidly increased, Early detection of gas leaks and alarms will not cause a detection delay. In particular, in the "high concentration (12500ppm) gas environment experiment, the requirement to detect and issue an alarm within 60 seconds of gas leakage" can not only be achieved, but also can reduce battery power consumption to achieve power saving (see Figure 4 for details). Figure 5 illustrates). Further, in the present embodiment, by the processing of S10 and S11, or S4 and S9, the number of times of sensor driving in a short period (20 seconds) is limited, and unnecessary power consumption can be suppressed. In other words, 'after measuring the gas -19-201246138 concentration exceeds the first reference concentration (after the alarm is issued), the sensor drive cycle Ta is restored to the normal drive for 45 seconds, which can suppress unnecessary power consumption. When the state of the sensor is driven in a short period (20 seconds), if the measured gas concentration does not exceed the first reference concentration and the number of times of driving (the number of detections) has reached a predetermined number of times, the sensor driving period Ta is made from a short period ( 20 seconds) Restoring to the normal drive period (45 seconds), unnecessary power consumption can be suppressed. Next, an example of the operation performed by the present embodiment will be described with reference to FIGS. 4 and 5. Fig. 4 is a graph showing the relationship between the gas concentration change in the gas sensor 11 and the reference concentration when the conventional gas detector is exposed to high concentration (1 2500 ppm) of gas. Fig. 5 is a diagram showing the relationship between the change in gas concentration (conditions as in Fig. 4) and the two kinds of reference concentrations when the replacement cost is 10, and the gas concentration in the gas sensor 11 is sensed by the body of the detector 10. The chamber configuration, the gas sensor configuration, or the filter structure provided to filter other gases may be affected, and may not be immediately synchronized with the ambient gas concentration, but will gradually approach the ambient gas concentration. When the gas detector 1 is placed in a high concentration gas, as shown in the figure, the gas concentration in the gas sensor 1 1 gradually rises to approach the surrounding gas concentration. In addition, the time point at which the gas starter 1 is placed in the high-concentration gas can be regarded as the time point at which the gas leak occurs. Further, in this example, as shown in the figure, after 34 seconds from the start of the gas leak, the gas The gas concentration in the sensor 1 (i.e., the measured gas concentration) should exceed the first reference concentration (alarm standard). -20- 201246138 Under the above conditions, when the gas concentration rises sharply, the gas leakage alarm must be issued within 1 minute. However, if the sensor is driven only for a normal 45 second period, depending on the sensor driving time, it may not be possible to issue a gas leak alarm within 1 minute after the gas leak occurs. Specifically, if the sensor drive time is in the T2 interval in Figure 4, the gas leak alarm cannot be issued within 1 minute. The details are described below. First, consider the normal sensor drive cycle (= 45 seconds), and the sensor drive time point falls within the T1 interval in Figure 4 (〇 ~ 15 seconds), in the T1 interval, because it does not exceed The first reference concentration does not emit a gas leak alarm. Since the sensor driving period is 45 seconds, the next-time sensor driving time point is 45 seconds after the driving, that is, the lower-second sensor driving time point falls within the T4 interval in FIG. 4 ( 45~60 seconds). In the T4 interval, a gas leak alarm is issued because the gas concentration has exceeded the first reference concentration. Therefore, even in the normal sensor drive cycle (45 seconds), as long as the sensor drive time falls within the T1 interval, the next drive time will be within 60 seconds after the gas leak occurs. At the next driving time point, the gas concentration exceeding the first reference concentration can be detected, so that the gas leakage alarm can be issued within 1 minute. Next, consider the normal sensor drive cycle (= 45 seconds), and the sensor drive time point falls within the T3 interval (34 to 45 seconds) in Figure 4, if gas detection is performed at that time. The gas leakage alarm can be immediately issued because the gas concentration in the gas sensor 11 has exceeded the first reference concentration. Finally, consider the normal sensor drive cycle (= 45 seconds), and the -21 - 201246138 sensor drive time point falls within the T2 interval (1 5~34 seconds) in Figure 4, at this point in time. Since the gas concentration 尙 does not exceed the first reference concentration, no gas leakage is reported. If the sensor drive period is maintained for 45 seconds, the next sensor drive time will fall at T 5 (60~7 9 seconds), and the concentration in the legend has exceeded 6000ppm (of course, the gas at this time) The concentration has already exceeded the first reference concentration. Although a gas leak alarm will be issued, the gas leak will be issued after the gas leak has occurred for more than 60 seconds, and the request for reporting is not satisfied within one minute. Applying the gas alarm 銮 10 of this example to the above experimental conditions, as shown in FIG. 5, the gas leakage θ report can be issued within 1 minute in any case. Further, when the gaster 10 of the present embodiment is used, if the sensor driving time point falls within the above-mentioned Τ1 or Τ3 section, of course, as in the conventional invention, the gas leak alarm can be issued within 1 minute. When the gas launcher 10 of this example is used, even if the sensor driving time point falls within the above T2 interval, the gas leak alarm can be issued within 1 minute. Further, in the example shown in Fig. 5, the measured gas concentration change is the same as that of the example of Fig. 4, and the θ report standard (first reference concentration) is also the same as the example of Fig. 4. In the gas detector 10 of the present method, the threshold 値 (second reference concentration) lower than the alarm standard (first reference concentration) is set at the same time. In the example shown in FIG. 5, the gas leakage starts to occur. After the second (start of the Τ2 interval), the measured gas concentration exceeds the second reference concentration. The following is an example of the case shown in Fig. 5, which illustrates the case where the sensor driving time point falls within the above Τ2 interval. -22- 201246138 First of all, as in the conventional invention, the normal sensor drive period (= 45 seconds) is considered, and the sensor drive time point falls within the T2 interval because the measured gas concentration exceeds the second reference concentration. At this time, the sensor drive period is changed from the above normal period (45 second period) to a short period (20 second period). Since the detection period (drive period) becomes 20 seconds, the next sensor drive time point falls within the T 6 interval of Fig. 5 (3 5 to 5 4 seconds). Therefore, at the next sensor driving time point, the measured gas concentration will exceed the first reference concentration, so the gas leakage alarm can be issued within 1 minute. As described above, the sensor driver of the gas alarm 10 of this example is used. The method, the normal situation is a 45 second cycle, the driving gas sensor does not need to consume additional power, which can reduce the battery usage. And only in the case of gas leakage doubts (when the second reference concentration is exceeded), the normal drive cycle (45 second cycle) is switched to a shorter drive cycle (20 second cycle), making it more normal than normal. A short sensor drive interval for gas detection. As a result, the increased current consumption can be minimized and a gas leak alarm can be issued early. In particular, when it is required to issue a gas leak alarm within one minute, power consumption can be suppressed, and a gas leak alarm can be issued within one minute, and a highly reliable alarm can be provided. Moreover, the relationship between the methane gas concentration and the elapsed time shown in FIG. 4 and FIG. 5 is only an example, and the relationship between the gas concentration and the elapsed time is due to the sensor chamber structure of the alarm body, the gas sensor structure, and the gas sensing. The filter type of the device varies, and the designer can appropriately determine the shorter driving cycle time or the number of short-cycle driving than the normal situation. -23- 201246138 Here, Figure 6 shows the timing diagram of the sensor drive when the gas concentration is slowly increased. As shown in the figure, in this case, since the measured gas concentration exceeds the second reference concentration, since the measurement has reached 5 times (short cycle detection count g 5 ) and the first reference concentration has not been exceeded, The 45 second cycle is resumed, and an alarm is issued at a point in time when the first reference concentration is exceeded. Moreover, the above-mentioned gas leak detection within 60 seconds is premised on a high concentration (1 2500 ppm) gas environment test, which is independent of the example shown in Fig. 6 (the gas concentration is slowly increased). Therefore, in the example of Fig. 6, although the gas leak detection test within 60 seconds has not been performed, it does not pose a problem. Further, Fig. 7 is a timing chart of the sensor driving in the modification in which steps S10 and S11 are not executed. In other words, the processing example shown in Fig. 3 is only an example, and is not limited to this example. For example, S 1 0 and S 1 1 may not be executed. In this case, although S 1 0 and S 1 1 are not executed, S4, S5, S6, and S9 perform the same processing. In other words, after the first reference concentration is exceeded, the 45-second period is not immediately restored, but the measured gas concentration is started from the second reference concentration, and the predetermined number of times (short period) is driven in a short period (20 seconds). Detection count = 5). In other words, in the case where the second reference concentration is exceeded, whether or not the first reference concentration is exceeded thereafter is uniformly driven in a short cycle (20 seconds) by a predetermined number of times (short cycle detection count = 5). The above description is not intended to be an example of a modification, and other modifications are possible. In any event, the present invention is not limited to the embodiment shown in Figs. 1 to 5 described above. -24- 201246138 In summary, the alarm device of the present invention under normal conditions, the pulse energization driving period for gas detection is long to reduce the battery usage; and the gas concentration of the tested gas exceeds the under-alarm warning standard. When the concentration is specified (the second reference concentration), the sensor drive cycle is shortened and gas detection is achieved early. Moreover, the number of times the sensor drive cycle is shortened can be limited to a predetermined number of times. In addition, the sensor drive cycle can be immediately restored to the original cycle after the gas concentration exceeds the alarm criteria. Thereby, the increased consumption current can be minimized, and the gas leakage alarm can be issued early. When the gas concentration changes rapidly, the detection delay does not occur, and an alarm can be issued at a specified gas concentration to provide a highly reliable gas alarm. The drive gas sensor does not consume extra power, which reduces battery usage, which in turn reduces battery count, reduces costs, and makes the machine smaller and lighter. Further, the control circuit unit 12 executes the application program or the like, and the gas alarm device 10 of the present example may include various functional units described below. In other words, the gas alarm 10 is a battery type gas alarm with a battery as a power source, and the gas leakage detection is performed according to the output of the gas sensor, and the gas sensor changes the electrical property according to the gas concentration of the gas to be inspected; This battery type gas alarm has the following various functional parts. First, the sensor drive function unit drives the function of the gas sensor by energizing the pulse at an arbitrary driving cycle, and normally drives the gas sensor in the first driving cycle. Further, the gas concentration calculation function unit calculates the gas concentration based on the output of the gas sensor when the sensor is driven, and the reporting function unit, when the calculated gas concentration of -25-201246138 exceeds the predetermined first threshold, Issue a false report. The driving cycle change function unit determines whether the gas concentration (measured gas concentration) calculated by the gas concentration calculating means exceeds the second enthalpy lower than the first enthalpy, and if the gas concentration exceeds the second enthalpy, The sensor drive function unit drives the gas sensor at a second drive cycle that is shorter than the first drive cycle. Further, for example, the drive cycle changing function unit may cause the number of times the gas sensor is driven by the second drive cycle to reach a predetermined number of times, or when the measured gas concentration exceeds the first turn, When the number of times the gas sensor is driven in the second driving period has reached a predetermined number of times, the driving period of the sensor driving function portion is restored to the first driving period. Further, for example, the drive cycle changing function unit may cause the drive cycle of the sensor drive function unit to return to the first drive cycle when the measured gas concentration exceeds the first threshold. By using the battery type gas detector and the control device of the present invention, the battery type gas detector using the battery as a power source can suppress battery consumption to save electricity, and at the same time, when the gas concentration rises rapidly, the gas can be emitted early. There is no detection delay when the leak is reported. BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] A configuration diagram showing an example of an embodiment of a gasp detector of the present invention. [Fig. 2] -26- 201246138 An example of a sensor drive timing chart of an embodiment. [Fig. 3] A flowchart of the process of determining the sensor drive period in the example of the embodiment (Fig. 4) A graph showing the relationship between the gas concentration and the elapsed time. Fig. 5 is a graph showing the relationship between the gas concentration and the elapsed time in an example of the embodiment. [Fig. 6] Timing diagram of the sensor drive when the gas concentration is slowly increased. [Fig. 7] The timing chart of the sensor drive in the modification of the step s 1 0, S 1 1 is not performed. [Fig. 8] An explanatory diagram of a sensor driving time point of a conventional battery type gas alarm. [Description of main component symbols] 1 〇: gas alarm 1 1 : gas sensor 1 2 : control circuit unit 1 3 : alarm unit 1 4 : ambient temperature detecting unit 1 5 : battery unit 1 1 a : sensor resistance -27- 201246138 1 1 b : Heater resistance 1 3 a : For the sound output unit 13b : Alarm display unit 1 3 c : External report output unit R : Load resistance SW1 , SW2 : Transistor switch ADI , AD2 : Input Terminals OUT1, OUT2: Output Terminals -28