JP3787963B2

JP3787963B2 - Water heater

Info

Publication number: JP3787963B2
Application number: JP16823997A
Authority: JP
Inventors: 順一植田; 寛明米久保
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1997-06-25
Filing date: 1997-06-25
Publication date: 2006-06-21
Anticipated expiration: 2017-06-25
Also published as: JPH1114148A

Description

【０００１】
【発明の属する技術分野】
本発明は、給湯の開始時に早く湯を供給することのできる給湯装置に関するものである。
【０００２】
【従来の技術】
従来この種の給湯装置には、図２１に示すようなものがあった（例えば特公平４−９９７２号公報）。同図において１は瞬間給湯機であり、給湯口２と瞬間給湯機１は給湯管３で結ばれている。給湯口２の手前には給湯弁４が設けられており、給湯管３の給湯弁４の上流側から排水管５が分岐しており、この排水管５には排水弁６が設けられている。また、排水管５の給湯管３からの分岐部には温度検出部７が設けられていて、温度設定器８の設定温度とこの温度検出部７の温度を比較して給湯制御部９が給湯弁４と排水弁６を制御している。
【０００３】
そして、給湯要求時に温度検出部７により検出された湯水の温度が温度設定器８の設定温度の許容範囲内の場合、給湯弁４を開き給湯口２に給湯管３内の湯水を供給するとともに、許容範囲外の場合、排水弁６を開き給湯管３内の湯水を排水管５を経て排水口から捨て、常に許容範囲内の温度の湯水を給湯口２から供給するというものである。
【０００４】
【発明が解決しようとする課題】
しかしながら上記したような従来の給湯装置では、出湯要求時に湯水の温度が許容範囲外、例えば低い場合、排水弁６を開き給湯管３内の湯水を排水口から捨てる動作をするため、給湯口２から湯が供給される迄の時間は大幅に改善することができないという課題を有していた。また給湯弁４、排水管５、排水弁６、温度検出部７などを現場で配管工事や配線工事を行って取り付ける必要があり、設置が大変であるとともに、通常の給湯装置では必要ない給湯弁４、排水管５、排水弁６、温度検出部７等の部材を必要とするという課題もあった。
【０００５】
本発明は上記した課題を解決するものであり、給湯装置自身の改善により、給湯の開始時に早く、かつ安全に湯を供給できる給湯装置を提供するものである。
【０００６】
【課題を解決するための手段】
本願発明は、給水管と給湯管が接続された熱交換器と、前記熱交換器を加熱する加熱手段と、前記加熱手段を調節する加熱調節手段と、前記熱交換器の近傍の温度を検出する温度検出手段と、水の流動を検出する流動検出手段と、前記熱交換器の出口近傍に設けたサーミスタと凍結防止ヒータを用い前記熱交換器内の空気噛みを検出する空気検出手段と、前記流動検出手段で水の流動を検出していない場合に前記温度検出手段で検出される温度が所定温度以下になったとき前記加熱調節手段を制御して前記加熱手段による前記熱交換器の加熱を開始し、予め設定した時間あるいは温度に達したとき加熱を停止するとともに、前記空気検出手段で空気噛みを検出した場合は、前記加熱手段による前記熱交換器の加熱を行わない停止時制御部とを具備し、前記空気検出手段は、空気検出開始後、凍結防止ヒータへの通電、サーミスタ温度Ｔ s の検出を繰り返し、サーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量を積分値∫ t0 ｄＴ s ・ｄｔとして求めて予め設定された水空気判別サーミスタ蓄熱熱量 e と比較し、∫ t0 ｄＴ s ・ｄｔ＞ e の場合は空気噛み状態と判定し、∫ t0 ｄＴ s ・ｄｔ≦ e の場合は水があると判定するようにしたもので、給湯の停止時に熱交換器が冷却されることを防止し、再給湯時に端末への湯の供給を早く行えるようにするとともに、空気検出器で空気噛みを検出している時は、熱交換器の加熱を行わないことにより、から焚きを防止し熱交換器内に蒸気が満たされ、給湯開始時に万一の異常温度上昇による危険等を防止しているものである。
【０００７】
【発明の実施の形態】
本発明の実施形態の一つは、給水管と給湯管が接続された熱交換器と、前記熱交換器を加熱する加熱手段と、前記加熱手段を調節する加熱調節手段と、前記熱交換器の近傍の温度を検出する温度検出手段と、水の流動を検出する流動検出手段と、前記熱交換器の出口近傍に設けたサーミスタと凍結防止ヒータを用い前記熱交換器内の空気噛みを検出する空気検出手段と、前記流動検出手段で水の流動を検出していない場合に前記温度検出手段で検出される温度が所定温度以下になったとき前記加熱調節手段を制御して前記加熱手段による前記熱交換器の加熱を開始し、予め設定した時間あるいは温度に達したとき加熱を停止するとともに、前記空気検出手段で空気噛みを検出した場合は、前記加熱手段による前記熱交換器の加熱を行わない停止時制御部とを具備し、前記空気検出手段は、空気検出開始後、凍結防止ヒータへの通電、サーミスタ温度Ｔ s の検出を繰り返し、サーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量を積分値∫ t0 ｄＴ s ・ｄｔとして求めて予め設定された水空気判別サーミスタ蓄熱熱量 e と比較し、∫ t0 ｄＴ s ・ｄｔ＞ e の場合は空気噛み状態と判定し、∫ t0 ｄＴ s ・ｄｔ≦ e の場合は水があると判定するようにしたものである。
【０００８】
したがって、給湯の停止時に熱交換器への水の流動が停止していることを流動検出手段で検出して、温度検出手段で検出される温度が所定温度以下になったら加熱手段による熱交換器の加熱を開始し、予め定めた時間あるいは温度に達したら加熱を停止することにより、給湯の停止時に熱交換器が冷却されることを防止し、再給湯時に給湯時の端末への湯の供給を早く行えるようにするとともに、空気検出器で空気噛みを検出している時は、加熱手段による熱交換器の加熱を開始する動作を行わないことにより、設置初期時や凍結防止のための水抜きの後など熱交換器内に空気が噛んでいる時に加熱を行い、熱交換器が空焚きされることを防止している。
【０００９】
特に、空気検出手段は、空気検出開始後、凍結防止ヒータへの通電、サーミスタ温度Ｔ s の検出を繰り返しサーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量を積分値∫ t0 ｄＴ s ・ｄｔとして求め予め設定された水空気判別サーミスタ蓄熱熱量 e と比較し、∫ t0 ｄＴ s ・ｄｔ＞ e の場合は空気噛み状態と判定し、∫ t0 ｄＴ s ・ｄｔ≦ e の場合は水があると判定する。そして、熱交換器内の水の有無を確実に判定できるので空焚きを防止することができる。
【００１０】
本発明の実施形態の他の一つは、給水管と給湯管が接続された熱交換器と、前記熱交換器を加熱する加熱手段と、前記加熱手段を調節する加熱調節手段と、前記熱交換器の近傍の温度を検出する温度検出手段と、水の流動を検出する流動検出手段と、前記熱交換器の出口近傍に設けたサーミスタと凍結防止ヒータを用い前記熱交換器内の空気噛みを検出する空気検出手段と、前記流動検出手段で水の流動を検出していない場合に前記温度検出手段で検出される温度が所定温度以下になったとき前記加熱調節手段を制御して前記加熱手段による前記熱交換器の加熱を開始し、予め設定した時間あるいは温度に達したとき加熱を停止するとともに、前記空気検出手段で空気噛みを検出した場合は、前記加熱手段による前記熱交換器の加熱を行わない停止時制御部とを具備し、前記空気検出手段は、空気検出開始後、凍結防止ヒータへ所定時間通電を行なってその発熱停止の後に、サーミスタ温度Ｔ s の検出を繰り返し、サーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量を積分値∫ t0 ｄＴ s ・ｄｔとして求め、予め設定された水空気判別サーミスタ蓄熱熱量 f と比較して∫ t0 ｄＴ s ・ｄｔ＞ f の場合は空気噛み状態と判定し、∫ t0 ｄＴ s ・ｄｔ≦ f の場合は水があると判定するようにした。
【００１１】
したがって、空気検出手段は、空気検出開始後、凍結防止ヒータへの所定時間の通電を行い発熱停止後、サーミスタ温度Ｔ s の検出を繰り返しサーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量を積分値∫ t0 ｄＴ s ・ｄｔとして求め予め設定された水空気判別サーミスタ蓄熱熱量 f と比較し、∫ t0 ｄＴ s ・ｄｔ＞ f の場合は空気噛み状態と判定し、∫ t0 ｄＴ s ・ｄｔ≦ f の場合は水があると判定する。そして、熱交換器内の水の有無を確実に判定できるので空焚きを防止することができる。
【００１２】
本発明の実施形態のさらに他の一つは、給水管と給湯管が接続された熱交換器と、前記熱交換器を加熱する加熱手段と、前記加熱手段を調節する加熱調節手段と、前記熱交換器の近傍の温度を検出する温度検出手段と、水の流動を検出する流動検出手段と、前記熱交換器の出口近傍に設けたサーミスタと凍結防止ヒータを用い前記熱交換器内の空気噛みを検出する空気検出手段と、前記流動検出手段で水の流動を検出していない場合に前記温度検出手段で検出される温度が所定温度以下になったとき前記加熱調節手段を制御して前記加熱手段による前記熱交換器の加熱を開始し、予め設定した時間あるいは温度に達したとき加熱を停止するとともに、前記空気検出手段で空気噛みを検出した場合は、前記加熱手段による前記熱交換器の加熱を行わない停止時制御部とを具備し、前記空気検出手段は、空気検出開始後、凍結防止ヒータへ所定時間通電を行って発熱させ、その発熱終了前後の一定時間ΔＦの間サーミスタ温度Ｔ s の検出を繰り返し、サーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量を積分値∫Δ F0 ｄＴ s ・ｄｔとして求め、予め設定された水空気判別サーミスタ蓄熱熱量 g と比較し、∫Δ F0 ｄＴ s ・ｄｔ＞ g の場合は空気噛み状態と判定し、∫ΔＦ 0 ｄＴ s ・ｄｔ≦ g の場合は水があると判定するようにした。
【００１３】
したがって、空気検出手段は、空気検出開始後、凍結防止ヒータへの所定時間の通電を行い発熱させ発熱終了前後の一定時間ΔＦの間サーミスタ温度Ｔ s の検出を繰り返しサーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量を積分値∫Δ F0 ｄＴ s ・ｄｔとして求め、予め設定された水空気判別サーミスタ蓄熱熱量 g と比較し、∫Δ F0 ｄＴ s ・ｄｔ＞ g の場合は空気噛み状態と判定し、∫Δ F0 ｄＴ s ・ｄｔ≦ g の場合は水があると判定する。そして、熱交換器内の水の有無を確実に判定できるので空焚きを防止することができる。
【００１４】
以下参考実施例を図面に基づいて説明する。
【００１５】
（参考実施例１）
図１において、熱交換器１０には、給水管１１と給湯管１２が接続されている。給水管１１には、熱交換器１０への水の流入を検出する流動検出手段である水量検出器１３、水温を検出する水温検出器１４が設けられている。熱交換器１０の出口のパイプには、空気噛みを検出するサーミスタ３１と凍結防止ヒータ３７を利用した空気検出器１５が設けられている。
【００１６】
また、熱交換器１０を迂回し給水管１１と給湯管１２を連絡するバイパス管１６が設けられ、このバイパス管１６には、熱交換器１０からの湯とバイパス管１６からの水の混合比を調節する水比例弁１７が設けられている。この水比例弁１７は、ソレノイドへの電流の調節によって水圧に対してバランスを取った弁が、バイパス管１６の開度を調節し通過する水量を調節するもので、電流の停止により全開状態で保持されるノーマルオープン型となっている。
【００１７】
熱交換器１０の近傍の給湯管１２には温度検出手段である湯温検出器１８が設けられ、また、バイパス管１６の合流点以降に水量制御弁１９、混合水温検出器２０が設けられている。給湯管１２は更に給湯装置本体２１外の給湯管２２に接続され、端末に設けた湯水混合栓２３に連通している。
【００１８】
制御器２４にはタイマー２５をしており、各種センサーの信号が取り込まれ、また各種アクチュエータへの信号や操作出力が出力されている。そして、制御器２４にはボリュームで構成された湯温設定器２５や停止時制御部２６が設けられている。熱交換器１０は、加熱手段であるガスバーナ２７で加熱され、このガスバーナ２７へのガス量を調節する加熱調節手段の一部としてガス比例弁２８が設けられている。
【００１９】
また、ガスのオン、オフは加熱調節手段の別の一部を構成する元電磁弁２９により行われる。なお、本参考実施例では燃料をガスで説明しているが石油等の他の燃料でも良い。
【００２０】
空気検出器１５の実装部は図２に示すように構成されている。空気検出器１５は保護管３０で保護されたサーミスタ３１が充填剤３２で充填され、リード線３３を外に臨ませて構成されており、固定具３４によりシール材３５でシールされて熱交換器１０の出口の水管３６に取りつけられている。凍結防止ヒータ３７はサーミスタ３１と対向するように水管３１に取り付けられている。
【００２１】
そして、凍結防止ヒータ３７を発熱させサーミスタ３１の抵抗値より温度を測定し、凍結防止ヒータ３７からサーミスタ３１への伝熱状態の変化から周囲に介在するものが水か空気か判断をしている。
【００２２】
次にこの参考実施例の動作を説明する。動作については、図３のフローチャートにその要部を示している。電源スイッチがオン操作され〈Ｓ１〉、かつ加熱スイッチがオン操作されていると〈Ｓ２〉、給湯の停止時において熱交換器１０を加熱できるモードに入る。この状態で水量検出器１３で検出される水の流量が所定値（例えば２l／min）を越えると、端末の湯水混合栓２３が開けられたと判断して通常の給湯モードに入り〈Ｓ３〉、設定された温度の湯を供給する。
【００２３】
また、湯温検出器１８で検出される出湯温度と設定の温度が比較され、水温検出器１４の水温と水量検出器１３の値が取り込まれ、水比例弁１７と水量制御弁１７、ガス比例弁２８が調節されて、所望の温度の湯が給湯管２２から供給される〈Ｓ４〉。水量検出器１３で検出される水の流量が所定値（例えば１．５l／min）以下の場合、あるいは給湯の停止時においては〈Ｓ３〉、給湯停止時の熱交換器１０への加熱モードが可能となる。
【００２４】
ここで、空気検出器１５が空気噛みを検出している時は、制御を止める加熱停止モードに移行し、バーナ２７による熱交換器１０への加熱を行わない〈Ｓ５〉。通電加熱後、十分時間が経過した後は、周囲温度の検出もでき、熱交換器１０の温度が異常に上昇した場合に補完的に温度検出を行っている。
【００２５】
空気検出器１５が空気噛みを検出していない時は、湯温検出器１８で検出される温度が所定温度として定めた下限値を下回ると〈Ｓ６〉、給湯装置全体が冷えていると停止時制御部２６が判断して流動停止時に於ける加熱モードを進める。湯温検出器１８と比較される下限値は、５０℃前後とし、湯温検出器１８で検出される温度がこの下限値以下であると、流動停止時に於ける加熱モードの次のステップに進む〈Ｓ６〉。
【００２６】
湯温検出器１８で検出される温度が下限値を下回ったら、まず、タイマー２５の設定された加熱時間を読み込む〈Ｓ７〉。次に、前回給湯を行った時のメモリーされた水温検出器１４で検出された水温と現在の水温を読み込む〈Ｓ８〉。これは、給水温度が何度であるかを判断し加熱時間や加熱開始温度を補正するためであり、水温が高い場合は時間は短目に温度は低目に、水温が低い場合は時間は長目に温度は高目になるように熱交換器１０を加熱する時間を補正する〈Ｓ９〉。
【００２７】
そして、再出湯時に給湯管１２を経て極力、設定温度に近い温度の湯を供給することに役立てている。次に、元電磁弁２９を開け〈Ｓ１１〉、同時にタイマー２５が計時を開始し〈Ｓ１２〉、ガス比例弁２８の開度を点火し易い開度１の状態にまで開けて点火を行う〈Ｓ１３〉。
【００２８】
次に、着火を確認しガス比例弁２８の開度を開度２の状態にまで絞る〈Ｓ１４〉。この開度は、通常の給湯が行われている状態での最小の開度に相当しており、この最小開度で加熱しても負荷が小さいため、熱交換器１０の温度は、次第に上昇して行く。
【００２９】
なお、給湯装置として最少加熱量が極めて低く取れる場合は、湯温検出器１８で検出される温度を一定に保つ方法も可能である。
【００３０】
熱交換器１０の加熱中に湯温検出器１８で検出される温度が異常な変化勾配を示す時は、熱交換器１０への空気噛み、あるいは加熱異常と判断して加熱を停止する〈Ｓ１５〉。加熱の開始を判断する所定値である下限値は、Ｔ1＝５０℃である。そして上限値Ｔ2を人が万一触れても火傷をしない程度の６０℃に定めている。
【００３１】
加熱時間は標準状態（水温１５℃、混合水温４０℃）で５秒間となっており、前述のように、水温に応じて補正がされている。
【００３２】
なお、タイマー２５が所定時間（５秒または５秒の補正値）を越えたら、タイムアップと見なし、停止動作に入る〈Ｓ１６〉。万が一、タイマー２５が故障したり、ガスバーナ２７の能力制御が故障して、湯温検出器１８で検出される温度が上限値（７０℃）を越えた場合は、直ちに温度優先で元電磁弁２９を閉成する停止動作に入る〈Ｓ１７〉。
【００３３】
また、補完的に空気検出器１５で検出される温度が上限値（７０℃）を越えた場合も、直ちに温度優先で元電磁弁２９を閉成する停止動作に入る〈Ｓ１８〉。加熱の停止に当たっては、元電磁弁２９が閉じられ〈Ｓ１９〉、以後、加熱の停止した後は、湯温検出器１８で検出される温度が所定温度である下限値以下になる迄は燃焼は停止している。
【００３４】
以上のような動作により、給湯停止時の湯の温度を一定値に保持し即出湯体制にしている。したがって一般の家庭用の給湯装置を想定すると、従来の給湯装置では配管長が５m程度のシステムで、端末の蛇口をひねってから約１５秒位かかって湯が供給されることが普通であったものが、本参考実施例品によれば５秒程度に短縮可能である。
【００３５】
従来の給湯装置は、保有水量等に起因する給湯装置自身の立ち上がりの時間が１０秒程度、また配管の保有水量を押し出す時間が５秒程度かかっていたが、本参考実施例品では給湯装置自身の立ち上がりの時間が短縮できるため、配管の滞留水の押し出し時間だけで済む結果となる。
【００３６】
（参考実施例２）
図４において、湯温検出器１５のサーミスタ３１は熱交換器１０近傍の温度を検出する湯温検出器１８のサーミスタ３８と共用している。空気検出動作は給湯動作を停止している場合にのみ作動するので給湯動作時における熱交換器１０の出口温度を計測する湯温検出器１８の動作を妨げることは無く湯温検出器１８の機能はサーミスタ３１とサーミスタ３８が別個の場合と何ら変わることはない。
【００３７】
また空気検出はサーミスタ３１と凍結防止ヒータ３７で行うので従来の給湯器と比較し部品点数を増やすことなく制御器２４のソフト内容を変更するだけで良い。よって給湯時に湯温制御を行うため必要とされる温度検出手段と空気検出手段のサーミスタとを共用することでサーミスタを２つから１つに削減し性能を低下させることなく低コスト化を図れる効果がある。
【００３８】
（参考実施例３）
図５は参考実施例３における空気検出手段１５を示す。熱交換器出口近傍の水管の同位置にサーミスタ３１と凍結防止ヒータ３７とを対向して水管３６に取り付けた構成としている。
【００３９】
よって、サーミスタ３１と凍結防止ヒータ３７を最短距離に配置でき、凍結防止ヒ―タ３７の加熱による水管３６・水管３６内の温度上昇をサーミスタ３１によって高速かつ顕著に検出することができる。加えて、短時間かつ精度良く水管内の水の有無が判定できる効果がある。また、サーミスタ３１と凍結防止ヒータ３７を近接する構成とし、サーミスタ３１による水管３６内の温度上昇の検出感度を落とし、凍結防止ヒータ３７の取付に便宜を図るようにしてもよい。なお近接とは水管３６の円筒方向及び円周方向に近い位置とする。
【００４０】
（参考実施例４）
図６、図７に参考実施例４を示す。
【００４１】
まず、基準温度Ｔ0を検出した（１）後、凍結防止ヒータへの一定時間の通電を行い発熱させ発熱停止直後、サーミスタの抵抗値を測定し発熱停止後温度Ｔ1を求め（２）、空気噛み判別値ΔＴ=Ｔ1−Ｔ0を算出し、予め器具の特性によって決めておいた水空気判別値ΔＴaより大きい場合は空気、小さい場合は水と判定する。
【００４２】
原理的には水がある場合は水がある分サーミスタ周辺の熱容量が大きくなり凍結防止ヒータからの伝達熱量が水管、水に吸収されてサーミスタの昇温が小さくなる。空気がある場合は空気の比熱が水に比べ著しく小さいのでサーミスタ周辺の熱容量が小さくなり凍結防止ヒータからの伝達熱量が水管と空気に吸収される結果サーミスタの昇温が大きくなることを利用している。
【００４３】
図８に発明者らの実験したデータを示す。凍結防止ヒータを１２０秒通電した後、自然放熱させた場合の経過時間と空気噛み判別値ΔＴ（ｄｅｇ）を水管に水が有る場合と空気が有る場合についてプロットしたものである。水が有る場合に比べ、空気が有る場合は空気噛み判別値ΔＴが大きくなるのがわかる。
【００４４】
また、凍結防止ヒータ通電後一定時間は水、空気がある場合とも凍結防止ヒータの余熱でサーミスタ温度が上昇を続け最大値を付けた後サーミスタ温度が下降に向かう。凍結防止ヒータ通電後サーミスタ温度が最大値を付けるまでの時間は空気の方が水に比べ速い。よって、水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００４５】
なお、凍結防止ヒータ通電加熱時間はサーミスタ周囲の温度が高くなるに従って凍結防止ヒータ通電加熱時間を長くし、加熱温度を上げることでサーミスタ周囲温度の影響を少なくしている。よってサーミスタ周囲の温度により凍結防止ヒータ通電加熱時間を変化させる方が空気噛み判別値ΔＴを精度良く算出できる。我々の実験では次の表のごとく最適な凍結防止ヒータ通電加熱時間を設定している。
【００４６】
【表１】

【００４７】
（参考実施例５）
図９、図１０に参考実施例５を示す。図９は空気噛みの検出動作原理図、図１０は空気噛み検出のフローチャートである。まず、基準温度Ｔ0を検出した（１）後、凍結防止ヒータへの一定時間の通電を行い発熱させる。
【００４８】
通電を断った後、ΔＬ経過した時点のサーミスタの抵抗値を測定しサーミスタ温度Ｔ1を求め（２）、空気噛み判別値ΔＴ=Ｔ1−Ｔ0を算出し、予め器具の特性によって決めておいた水空気判別値ΔＴaより大きい場合は空気、小さい場合は水と判定する。
【００４９】
原理的には凍結防止ヒータ通電後一定時間は水、空気がある場合とも凍結防止ヒータの余熱でサーミスタ温度が上昇を続け空気有りの最大値を付けた時点が水・空気の判定となる空気噛み判別値ΔＴの差が最も顕著となる。
【００５０】
この余熱で空気が有る場合にサーミスタの温度が最大値を付けるまでの時間をΔＬとすることで水空気の判別をより精度の高いものとすることができる。
【００５１】
図８の例では凍結防止ヒータの通電時間を１２０秒とした場合ΔＬ=６０秒が最適な設定値となる。そして水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００５２】
なお、凍結防止ヒータ通電加熱時間は実施例４と同様にサーミスタ周囲の温度が高くなるに従って凍結防止ヒータ通電加熱時間を長くし、加熱温度を上げることでサーミスタ周囲温度の影響を少なくし空気噛み判別値ΔＴを精度良く算出できるようにしている。
【００５３】
（参考実施例６）
図１１、図１２に参考実施例６を示す。図１１は空気噛みの検出動作原理図、図１２は空気噛み検出のフローチャートである。
【００５４】
空気噛み検出スタート（経過時間ｔ=０）よりサーミスタ温度Ｔsを測定、凍結防止ヒー
タ通電加熱を予め設定しておいた設定時間ｔｐを越えるまでｎ回繰り返し行い、その後計測したＴsとｔの関係よりサーミスタの加熱時温度勾配、すなわちサーミスタ温度時間的変化率ｄＴs／ｄｔを算出し、予め器具の特性によって決めておいた水空気判別サーミスタ
温度時間的変化率ｂより大きい場合は空気、小さい場合は水と判定する。
【００５５】
原理的には水がある場合は水がある分サーミスタ周辺の熱容量が大きくなり凍結防止ヒータからの伝達熱量が水管、水に吸収されてサーミスタの昇温が小さくなり温度勾配は小さくなる。空気がある場合は空気の比熱が水に比べ著しく小さいのでサーミスタ周辺の熱容量が小さくなり凍結防止ヒータからの伝達熱量が水管と空気に吸収される結果サーミスタの昇温が大きくなり温度勾配が大きいなることを利用している。
【００５６】
水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００５７】
なお、凍結防止ヒータ通電加熱時間は参考実施例４と同様にサーミスタ周囲の温度が高くなるに従って凍結防止ヒータ通電加熱時間を長くし、加熱温度を上げることでサーミスタ周囲温度の影響を少なくしサーミスタ温度時間的変化率ｄＴs／ｄｔを精度良く算出できるようにしている。
【００５８】
（参考実施例７）
図１３、図１４に実施例７を示す。図１３は空気噛みの検出動作原理図、図１４は空気噛み検出のフローチャートである。
【００５９】
まず、凍結防止ヒータへの一定時間の通電を行い発熱させる。通電を断った後、ΔＬ経過した時点よりサーミスタ温度Ｔsの計測を開始し（経過時間ｔ=０）、予め設定しておいた設定時間ｔｑを越えるまでｎ回繰り返し行い、その後計測したＴsとｔの関係よりサーミスタの放熱時温度勾配、すなわちサーミスタ温度時間的変化率ｄＴs／ｄｔを算出し、予
め器具の特性によって決めておいた水空気判別サーミスタ温度時間的変化率ｃより大きい場合は水、小さい場合は空気と判定する。
【００６０】
原理的には、凍結防止ヒータ通電後は水、空気がある場合とも凍結防止ヒータの余熱でサーミスタ温度が上昇を続け空気有りの場合が最大値を付け下降に転じた後も水有りの場合は一定時間温度上昇を続け最大値に達することを利用する。
【００６１】
つまり、ΔＬを余熱で空気が有る場合にサーミスタの温度が最大値を付けるまでの時間に設定することでΔＬ経過後の温度勾配は水が有る場合は正の傾き、空気が有る場合は負の傾きとなるので水空気の判別をより精度の高いものとすることができる。
【００６２】
水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００６３】
なお、凍結防止ヒータ通電加熱時間は参考実施例４と同様にサーミスタ周囲の温度が高くなるに従って凍結防止ヒータ通電加熱時間を長くし、加熱温度を上げることでサーミスタ周囲温度の影響を少なくしサーミスタ温度時間的変化率ｄＴs／ｄｔを精度良く算出できるようにしている。
【００６４】
以上各参考実施例を踏まえ以下その実施例を説明する。
【００６５】
（実施例１）
図１５、図１６において、空気噛み検出スタート（経過時間ｔ=０）よりサーミスタ温度Ｔsを測定、凍結防止ヒータ通電加熱を予め設定しておいた設定時間ｔｒを越えるまでｎ回繰り返し行い、その後計測したＴsとｔの関係よりサーミスタの加熱時の蓄熱熱量を積分値∫tr0ｄＴs・ｄｔとして求め、予め設定された水空気判別サーミスタ蓄熱熱量eより大きい場合は空気、小さい場合は水と判定する。
【００６６】
原理的には水がある場合は水がある分サーミスタ周辺の熱容量が大きくなり凍結防止ヒータからの伝達熱量が水管、水に吸収されてサーミスタの昇温が小さくなり蓄熱熱量∫tr0ｄＴs・ｄｔは小さくなる。
【００６７】
空気がある場合は空気の比熱が水に比べ著しく小さいのでサーミスタ周辺の熱容量が小さくなり凍結防止ヒータからの伝達熱量が水管と空気に吸収される結果サーミスタの昇温が大きくなり蓄熱熱量∫tr0ｄＴs・ｄｔが大きくなることを利用している。
【００６８】
水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００６９】
なお、凍結防止ヒータ通電加熱時間は参考実施例４と同様にサーミスタ周囲の温度が高くなるに従って凍結防止ヒータ通電加熱時間を長くし、加熱温度を上げることでサーミスタ周囲温度の影響を少なくしサーミスタの蓄熱熱量∫tr0ｄＴs・ｄｔを精度良く算出できるようにしている。
【００７０】
（実施例２）
図１７、図１８において、まず、凍結防止ヒータへの一定時間の通電を行い発熱させる。通電を断った後、サーミスタ温度Ｔsの計測を開始し（経過時間ｔ=０）、予め設定しておいた設定時間ｔｓを越えるまでｎ回繰り返し行い、その後計測したＴsとｔの関係よりサーミスタの放熱時の蓄熱熱量と積分値∫ts0ｄＴs・ｄｔとして求め、予め設定された水空気判別サーミスタ蓄熱熱量ｆより大きい場合は空気、小さい場合は水と判定する。
【００７１】
水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００７２】
なお、凍結防止ヒータ通電加熱時間は実施例４と同様にサーミスタ周囲の温度が高くなるに従って凍結防止ヒータ通電加熱時間を長くし、加熱温度を上げることでサーミスタ周囲温度の影響を少なくしサーミスタの蓄熱熱量∫ts0ｄＴs・ｄｔを精度良く算出できるようにしている。
【００７３】
（実施例３）
図１９、図２０において、まず、凍結防止ヒータへの通電を行い発熱させ発熱終了前後の一定時間ΔＦの間サーミスタ温度Ｔsの検出を繰り返す。図１９の例では凍結防止ヒータ通電終了時間より１／２・ΔＦ前をサーミスタ温度計測の開始時（ｔ=０）とし残りのサーミスタ計測時間１／２・ΔＦはサーミスタ通電終了時間後となる。
【００７４】
一定時間ΔＦ経過後、サーミスタ温度Ｔsと経過時間ｔの測定結果よりサーミスタの蓄熱熱量を積分値∫ΔF0ｄＴs・ｄｔとして求め予め設定された水空気判別サーミスタ蓄熱熱量gと比較しｇより大きい場合は空気噛み状態と判定し、小さい場合は水があると判定する。
【００７５】
原理的には実施例１と実施例２を融合した形となり温度変化が最も激しいサーミスタ加熱終了前後のみのサーミスタへの蓄熱熱量により水の有無を判定するため、より精度の高い判定ができる。
【００７６】
水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００７７】
なお、凍結防止ヒータ通電加熱時間は参考実施例４と同様にサーミスタ周囲の温度が高くなるに従って凍結防止ヒータ通電加熱時間を長くし、加熱温度を上げることでサーミスタ周囲温度の影響を少なくしサーミスタの蓄熱熱量∫ΔF0ｄＴs・ｄｔを精度良く算出できるようにしている。
【００７８】
以上のように参考実施例および実施例の給湯装置の意義は以下の通りである。
【００７９】
（１）給湯の停止時に熱交換器への水の流動が停止していることを流動検出手段で検出して、温度検出手段で検出される温度が所定温度以下になったら加熱調節手段で加熱手段による熱交換器の加熱を開始し、予め定めた時間あるいは温度に達したら加熱を停止することにより、給湯の停止時に熱交換器が冷却されることを防止し、再給湯時に熱交換器内の保有水を加熱する時間を節約して、給湯装置本体だけで給湯時の端末における湯の供給を早く行える。また、凍結防止ヒータを利用した空気検出器で空気噛みを検出している時は、加熱手段による熱交換器の加熱を行わないので、設置初期時や凍結防止のための水抜きの後などに熱交換器内に空気が噛んでいる時に加熱を行い、熱交換器が空焚きされることを防止して安全性の向上と耐久性維持を図ることができる。
【００８０】
（２）熱交換器近傍の温度を検出する温度検出手段と空気検出手段のサーミスタとを共用することでサーミスタを２つから１つに削減し低コスト化を図れる効果がある。また、空気検出動作は給湯動作を停止している場合にのみ作動するので給湯動作時における熱交換器の出口温度を計測する温度検出手段の動作を妨げることは無く温度検出手段の機能と空気検出手段の機能を両立することができる。
【００８１】
（３）熱交換器出口近傍の水管の同位置にサーミスタと凍結防止ヒータとを対向して取り付けた構成としたことでサーミスタと凍結防止ヒータを最短距離に配置でき、凍結防止ヒ―タの加熱による水管・水管内の温度上昇をサーミスタによって高速かつ顕著に検出することができる。よって短時間かつ精度良く水管内の水の有無が判定でき、熱交換器の空焚きを防止することができる。
【００８２】
（４）空気検出手段は、空気検出開始後、サーミスタにより基準温度Ｔ 0 を測定した後凍結防止ヒータへの一定時間の通電を行い発熱させ発熱停止直後、再度発熱後温度Ｔ 1 を測定し発熱後温度Ｔ 1 と基準温度Ｔ 0 との差ΔＴを予め設定された水空気判定温度差ΔＴ a と比較しΔＴ＞ΔＴ a の場合は空気噛み状態と判定しΔＴ≦ΔＴ a の場合は水があると判定するので熱交換器内の水の有無を確実に判断し水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００８３】
（５）空気検出手段は、空気検出開始後、サーミスタにより基準温度Ｔ 0 を測定した後凍結防止ヒータへの一定時間の通電を行い発熱させ発熱停止後、一定時間ΔＬ経過した後、再度発熱後温度Ｔ 1 を測定し発熱後温度Ｔ 1 と基準温度Ｔ 0 との差ΔＴを予め設定された水空気判定温度差ΔＴ a と比較しΔＴ＞ΔＴ a の場合は空気噛み状態と判定しΔＴ≦ΔＴ a の場合は水があると判定するので熱交換器内の水の有無を確実に判断し水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００８４】
（６）空気検出手段は、空気検出開始後、凍結防止ヒータへの通電、サーミスタ温度Ｔ s の検出を繰り返しサーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタ温度時間的変化率ｄＴ s ／ｄｔを求め予め設定された水空気判別サーミスタ温度時間的変化率ｂと比較しｄＴ s ／ｄｔ＞ｂの場合は空気噛み状態と判定しｄＴ s ／ｄｔ≦ｂの場合は水があると判定するので熱交換器内の水の有無を確実に判断し水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００８５】
（７）空気検出手段は、空気検出開始後、凍結防止ヒータへの一定時間の通電を行い発熱停止後、一定時間ΔＬ経過した後、サーミスタ温度Ｔ s の検出を繰り返しサーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタ温度時間的変化率ｄＴ s ／ｄｔを求め予め設定された水空気判別サーミスタ温度時間的変化率 c と比較しｄＴ s ／ｄｔ≦ c の場合は空気噛み状態と判定しｄＴ s ／ｄｔ＞ c の場合は水があると判定するので熱交換器内の水の有無を確実に判断し水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００８６】
（８）空気検出手段は、空気検出開始後、凍結防止ヒータへの通電、サーミスタ温度Ｔ s の検出を繰り返しサーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量∫ t0 ｄＴ s ・ｄｔを求め予め設定された水空気判別サーミスタ蓄熱熱量 e と比較し∫ t0 ｄＴ s ・ｄｔ＞ e の場合は空気噛み状態と判定し∫ t0 ｄＴ s ・ｄｔ≦ e の場合は水があると判定するので熱交換器内の水の有無を確実に判断し水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００８７】
（９）空気検出手段は、空気検出開始後、凍結防止ヒータへの一定時間の通電を行い発熱停止後、サーミスタ温度Ｔ s の検出を繰り返しサーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量∫ t0 ｄＴ s ・ｄｔを求め予め設定された水空気判別サーミスタ蓄熱熱量 f と比較し∫ t0 ｄＴ s ・ｄｔ＞ f の場合は空気噛み状態と判定し∫ t0 ｄＴ s ・ｄｔ≦ f の場合は水があると判定するので熱交換器内の水の有無を確実に判断し水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００８８】
（１０）空気検出手段は、空気検出開始後、凍結防止ヒータへの一定時間の通電を行い発熱させ発熱終了前後の一定時間ΔＦの間サーミスタ温度Ｔ s の検出を繰り返しサーミスタ温度Ｔ s と経過時間ｔの測定結果よりサーミスタの蓄熱熱量∫Δ F0 ｄＴ s ・ｄｔを求め予め設定された水空気判別サーミスタ蓄熱熱量 g と比較し∫Δ F0 ｄＴ s ・ｄｔ＞ g の場合は空気噛み状態と判定し∫Δ F0 ｄＴ s ・ｄｔ≦ g の場合は水があると判定するので熱交換器内の水の有無を確実に判断し水が有ると判定された場合は加熱モードへ進みバーナによる加熱が開始され、即出湯体制にはいる。空気噛みと判定された場合は加熱停止モードに進みバーナによる加熱は中止され、熱交換器の空焚きを防止することができる。
【００８９】
【発明の効果】
以上説明したように本発明の給湯装置は、給湯の停止時に熱交換器が冷却されることを防止し、再給湯時に給湯時の端末への湯の供給を早く行えるようにするとともに、空気検出器で空気噛みを検出している時は、加熱手段による熱交換器の加熱を開始する動作を行わないことにより、熱交換器の空焚きを確実に防止できるものである。
【図面の簡単な説明】
【図１】本発明の参考実施例１における給湯装置の構成図
【図２】同給湯装置のサーミスタの取付状態を示す部分断面図
【図３】同給湯装置の要部動作のフローチャート
【図４】本発明の参考実施例２における給湯装置の構成図
【図５】本発明の参考実施例３における給湯装置に用いた空気検出器の切り欠き断面図
【図６】本発明の参考実施例４における給湯装置の要部動作を説明する図
【図７】同給湯装置の要部動作のフローチャート
【図８】同給湯装置の原理を実験データに基づいて説明する図
【図９】本発明の参考実施例５における給湯装置の要部動作を説明する図
【図１０】同給湯装置の要部動作のフローチャート
【図１１】本発明の参考実施例６における給湯装置の要部動作を説明する図
【図１２】同給湯装置の要部動作のフローチャート
【図１３】本発明の参考実施例７における給湯装置の要部動作を説明する図
【図１４】同給湯装置の要部動作のフローチャート
【図１５】本発明の実施例１における給湯装置の要部動作を説明する図
【図１６】同給湯装置の要部動作のフローチャート
【図１７】本発明の実施例２における給湯装置の要部動作を説明する図
【図１８】同給湯装置の要部動作のフローチャート
【図１９】本発明の実施例３における給湯装置の要部動作を説明する図
【図２０】同給湯装置の要部動作のフローチャート
【図２１】従来の給湯装置の構成図
【符号の説明】
１０熱交換器
１１給水管
１２給湯管
１３水量検出器
１５空気検出器
１８湯温検出器（温度検出手段）
２４制御器
２６停止時制御部
２７ガスバーナ
２８ガス比例弁（加熱調節手段）
２９元電磁弁
３１サーミスタ（空気検出手段）
３７凍結防止ヒータ
３８サーミスタ（温度検出手段）[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a hot water supply apparatus capable of supplying hot water early at the start of hot water supply.
[0002]
[Prior art]
  Conventionally, there has been a hot water supply apparatus of this type as shown in FIG. 21 (for example, Japanese Patent Publication No. 4-9972). In the figure, 1 is an instantaneous water heater, and the hot water inlet 2 and the instantaneous water heater 1 are connected by a hot water pipe 3. A hot water supply valve 4 is provided in front of the hot water supply port 2, a drain pipe 5 is branched from the upstream side of the hot water supply valve 4 of the hot water supply pipe 3, and a drain valve 6 is provided in the drain pipe 5. . Further, a temperature detection unit 7 is provided at a branch portion of the drain pipe 5 from the hot water supply pipe 3, and the hot water supply control unit 9 compares the set temperature of the temperature setting device 8 with the temperature of the temperature detection unit 7. The valve 4 and the drain valve 6 are controlled.
[0003]
  And when the temperature of the hot water detected by the temperature detector 7 at the time of the hot water supply request is within the allowable range of the set temperature of the temperature setter 8, the hot water valve 4 is opened and hot water in the hot water supply pipe 3 is supplied to the hot water supply port 2. When the temperature is outside the allowable range, the drain valve 6 is opened, the hot water in the hot water supply pipe 3 is discarded from the drain through the drain pipe 5, and hot water having a temperature within the allowable range is always supplied from the hot water supply 2.
[0004]
[Problems to be solved by the invention]
  However, in the conventional hot water supply apparatus as described above, when the temperature of the hot water is outside the allowable range at the time of requesting hot water, for example, it is low, the drain valve 6 is opened and the hot water in the hot water supply pipe 3 is discarded from the drain port. The time until the hot water is supplied from the hot water cannot be improved significantly. Also, it is necessary to install the hot water supply valve 4, the drain pipe 5, the drain valve 6 and the temperature detection unit 7 by performing piping work and wiring work at the site, which is difficult to install and is not necessary for a normal hot water supply device. There also existed the subject that members, such as 4, the drain pipe 5, the drain valve 6, and the temperature detection part 7, were required.
[0005]
  The present invention solves the above-described problems, and provides a hot water supply device that can supply hot water quickly and safely at the start of hot water supply by improving the hot water supply device itself.
[0006]
[Means for Solving the Problems]
  The present invention isA heat exchanger in which a water supply pipe and a hot water supply pipe are connected, a heating means for heating the heat exchanger, a heating adjustment means for adjusting the heating means, and a temperature detection means for detecting the temperature in the vicinity of the heat exchanger Flow detection means for detecting the flow of water, air detection means for detecting air biting in the heat exchanger using a thermistor and an antifreeze heater provided in the vicinity of the outlet of the heat exchanger, and the flow detection means When the temperature detected by the temperature detection means is not more than a predetermined temperature when the flow of water is not detected in the control of the heating adjustment means to start heating the heat exchanger by the heating means, The heating is stopped when a preset time or temperature is reached, and when the air detection means detects air biting, it includes a stop time control unit that does not heat the heat exchanger by the heating means. The above Gas detection means, after air detection start energization of the antifreeze heater, thermistor temperature T s Detection, and the thermistor temperature T s And the measurement result of the elapsed time t, the accumulated heat quantity of the thermistor t0 dT s -Pre-set water / air discrimination thermistor heat storage heat quantity obtained as dt e Compare with ∫ t0 dT s ・ Dt> e In the case of t0 dT s ・ Dt ≦ e In this case, it is determined that there is water, so that the heat exchanger is prevented from being cooled when hot water supply is stopped, hot water can be supplied to the terminal quickly when hot water is supplied, and air detection is performed. When the air catching is detected by the heat exchanger, the heat exchanger is not heated, so that the heat exchanger is prevented from being swallowed and the heat exchanger is filled with steam. It is what is preventing.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
  One embodiment of the present invention includes a heat exchanger in which a water supply pipe and a hot water supply pipe are connected, a heating means for heating the heat exchanger, a heating adjustment means for adjusting the heating means, and the heat exchanger. Temperature detection means for detecting the temperature in the vicinity of the water, flow detection means for detecting the flow of water, thermistor provided near the outlet of the heat exchanger and an antifreeze heater to detect the air jam in the heat exchanger Sky And when the temperature detected by the temperature detecting means is lower than a predetermined temperature when the flow of water is not detected by the flow detecting means, the heating adjusting means is controlled to control the heating by the heating means. Heating of the heat exchanger is started, and when the preset time or temperature is reached, the heating is stopped, and when the air detection is detected by the air detecting means, the heat exchanger is heated by the heating means. A non-stop control unit, and the air detection means energizes the anti-freezing heater after the start of air detection, the thermistor temperature T s Detection, and the thermistor temperature T s And the measurement result of the elapsed time t, the accumulated heat quantity of the thermistor t0 dT s -Pre-set water / air discrimination thermistor heat storage heat quantity obtained as dt e Compare with ∫ t0 dT s ・ Dt> e In the case of t0 dT s ・ Dt ≦ e In the case of, it is determined that there is water.
[0008]
  Therefore, when the flow of water to the heat exchanger is stopped when the hot water supply is stopped, the flow detecting means detects the heat exchanger, and when the temperature detected by the temperature detecting means falls below a predetermined temperature, the heat exchanger by the heating means Heating of the heat exchanger is stopped and the heating is stopped when a predetermined time or temperature is reached, so that the heat exchanger is prevented from being cooled when hot water is stopped, and hot water is supplied to the terminal during hot water supply. When the air detector detects air biting, do not start the heating of the heat exchanger by the heating means. Heating is performed when air is caught in the heat exchanger, such as after removal, to prevent the heat exchanger from being blown.
[0009]
  In particular, the air detection means is configured to supply current to the antifreeze heater after the start of air detection, and to detect the thermistor temperature T. s Thermistor temperature T s And the measurement result of the elapsed time t, the accumulated heat quantity of the thermistor t0 dT s -Pre-set water / air discrimination thermistor heat storage heat quantity obtained as dt e Compare with ∫ t0 dT s ・ Dt> e In the case of t0 dT s ・ Dt ≦ e In the case of, it is determined that there is water. And since the presence or absence of the water in a heat exchanger can be determined reliably, it can prevent emptying.
[0010]
  Another embodiment of the present invention includes a heat exchanger in which a water supply pipe and a hot water supply pipe are connected, a heating means for heating the heat exchanger, a heating adjustment means for adjusting the heating means, and the heat A temperature detecting means for detecting the temperature in the vicinity of the exchanger, a flow detecting means for detecting the flow of water, a thermistor provided near the outlet of the heat exchanger, and an antifreeze heater, and the air engagement in the heat exchanger Air detection means for detecting the flow of water, and when the flow detected by the flow detection means does not detect the flow of water, the heating adjustment means is controlled to control the heating when the temperature detected by the temperature detection means falls below a predetermined temperature. The heating of the heat exchanger by the heating means is started, and when the preset time or temperature is reached, the heating is stopped. Do not heat Comprising a stop control unit, said air detection means, after air detection start, after the heat generation stop is performed for a predetermined time energizing the antifreeze heater, thermistor temperature T s Detection, and the thermistor temperature T s And the measurement result of the elapsed time t, the accumulated heat quantity of the thermistor t0 dT s ・ Determined as dt, preset water-air discrimination thermistor heat storage heat amount f ∫ compared with t0 dT s ・ Dt> f In the case of t0 dT s ・ Dt ≦ f In the case of, it was determined that there was water.
[0011]
  Therefore, the air detecting means energizes the anti-freezing heater for a predetermined time after starting the air detection, stops the heat generation, and then detects the thermistor temperature T. s Thermistor temperature T s And the measurement result of the elapsed time t, the accumulated heat quantity of the thermistor t0 dT s -Pre-set water / air discrimination thermistor heat storage heat quantity obtained as dt f Compare with ∫ t0 dT s ・ Dt> f In the case of t0 dT s ・ Dt ≦ f In the case of, it is determined that there is water. And since the presence or absence of the water in a heat exchanger can be determined reliably, it can prevent emptying.
[0012]
  Still another embodiment of the present invention includes a heat exchanger in which a water supply pipe and a hot water supply pipe are connected; Heating means for heating the heat exchanger, heating adjusting means for adjusting the heating means, temperature detecting means for detecting the temperature in the vicinity of the heat exchanger, flow detecting means for detecting the flow of water, and the heat An air detection means for detecting air entrainment in the heat exchanger using a thermistor and an antifreeze heater provided near the outlet of the exchanger, and the temperature detection means when the flow detection means does not detect water flow When the temperature detected by the control unit becomes equal to or lower than a predetermined temperature, the heating control unit is controlled to start heating the heat exchanger by the heating unit, and when the preset time or temperature is reached, the heating is stopped. And a stop control unit that does not heat the heat exchanger by the heating means when the air detection means detects air bite, and the air detection means has a freeze prevention function after the start of air detection. Heat is generated by performing a predetermined time energizing the motor, thermistor temperature T for a predetermined time ΔF of the heating before and after completion s Detection, and the thermistor temperature T s And the measurement result of the elapsed time t, the accumulated heat quantity of the thermistor F0 dT s ・ Determined as dt, preset water-air discrimination thermistor heat storage heat amount g Compared to ∫Δ F0 dT s ・ Dt> g In the case of, it is determined that the air is in the air-engaged state and ∫ΔF 0 dT s ・ Dt ≦ g In the case of, it was determined that there was water.
[0013]
  Therefore, the air detection means energizes the anti-freezing heater for a predetermined time after starting the air detection to generate heat, and the thermistor temperature T for a certain time ΔF before and after the end of the heat generation. s Thermistor temperature T s And the measurement result of the elapsed time t, the accumulated heat quantity of the thermistor F0 dT s ・ Determined as dt, preset water-air discrimination thermistor heat storage heat amount g Compared to ∫Δ F0 dT s ・ Dt> g In the case of F0 dT s ・ Dt ≦ g In the case of, it is determined that there is water. And since the presence or absence of the water in a heat exchanger can be determined reliably, it can prevent emptying.
[0014]
  Reference examples will be described below with reference to the drawings.
[0015]
  (Reference Example 1)
  In FIG.A water supply pipe 11 and a hot water supply pipe 12 are connected to the heat exchanger 10. The water supply pipe 11 is provided with a water amount detector 13 which is a flow detection means for detecting the inflow of water into the heat exchanger 10 and a water temperature detector 14 for detecting the water temperature. An air detector 15 using a thermistor 31 and an antifreeze heater 37 for detecting air biting is provided at the outlet pipe of the heat exchanger 10.
[0016]
  Further, a bypass pipe 16 that bypasses the heat exchanger 10 and connects the water supply pipe 11 and the hot water supply pipe 12 is provided, and the bypass pipe 16 has a mixing ratio of hot water from the heat exchanger 10 and water from the bypass pipe 16. A water proportional valve 17 is provided for adjusting the pressure. This water proportional valve 17 is a valve that balances the water pressure by adjusting the current to the solenoid, and adjusts the amount of water that passes through the opening of the bypass pipe 16. It is a normally open type that is retained.
[0017]
  The hot water supply pipe 12 in the vicinity of the heat exchanger 10 is provided with a hot water temperature detector 18 as temperature detecting means, and a water amount control valve 19 and a mixed water temperature detector 20 are provided after the junction of the bypass pipe 16. Yes. The hot water supply pipe 12 is further connected to a hot water supply pipe 22 outside the hot water supply apparatus main body 21 and communicates with a hot water mixing plug 23 provided at the terminal.
[0018]
  The controller 24 has a timer 25, which receives signals from various sensors, and outputs signals and operation outputs to various actuators. The controller 24 is provided with a hot water temperature setting device 25 configured by a volume and a stop time control unit 26. The heat exchanger 10 is heated by a gas burner 27 which is a heating means, and a gas proportional valve 28 is provided as a part of the heating adjustment means for adjusting the amount of gas to the gas burner 27.
[0019]
  The gas is turned on and off by the original electromagnetic valve 29 that constitutes another part of the heating control means. In addition,This reference exampleThe fuel is described as gas, but other fuels such as oil may be used.
[0020]
  The mounting portion of the air detector 15 is configured as shown in FIG. The air detector 15 is configured such that a thermistor 31 protected by a protective tube 30 is filled with a filler 32 and a lead wire 33 is exposed to the outside. The air detector 15 is sealed with a sealing material 35 by a fixture 34 and is heat exchanger. 10 outlet water pipes 36 are attached. The antifreezing heater 37 is attached to the water pipe 31 so as to face the thermistor 31.
[0021]
  Then, the antifreeze heater 37 is heated to measure the temperature from the resistance value of the thermistor 31, and it is determined from the change in the heat transfer state from the antifreeze heater 37 to the thermistor 31 whether the surrounding is water or air. .
[0022]
  Then thisReference exampleThe operation of will be described. The main part of the operation is shown in the flowchart of FIG. When the power switch is turned on <S1> and the heating switch is turned on <S2>, a mode is entered in which the heat exchanger 10 can be heated when hot water supply is stopped. In this state, when the flow rate of water detected by the water amount detector 13 exceeds a predetermined value (for example, 2 l / min), it is determined that the hot and cold water mixing plug 23 of the terminal has been opened, and the normal hot water supply mode is entered <S3>, Supply hot water at the set temperature.
[0023]
  Further, the hot water temperature detected by the hot water temperature detector 18 is compared with the set temperature, the water temperature of the water temperature detector 14 and the value of the water amount detector 13 are taken in, the water proportional valve 17, the water amount control valve 17, and the gas proportional. The valve 28 is adjusted, and hot water of a desired temperature is supplied from the hot water supply pipe 22 <S4>. When the flow rate of water detected by the water amount detector 13 is a predetermined value (for example, 1.5 l / min) or less, or when hot water supply is stopped, <S3>, the heating mode for the heat exchanger 10 when hot water supply is stopped is It becomes possible.
[0024]
  Here, when the air detector 15 detects the air bite, the operation is shifted to the heating stop mode in which the control is stopped, and the heat exchanger 10 is not heated by the burner 27 <S5>. After a sufficient amount of time has elapsed after energization heating, the ambient temperature can also be detected, and the temperature detection is complementarily performed when the temperature of the heat exchanger 10 rises abnormally.
[0025]
  When the air detector 15 has not detected the air bite, when the temperature detected by the hot water temperature detector 18 falls below the lower limit set as the predetermined temperature <S6>, when the entire hot water supply device is cold, it stops. The control unit 26 determines and advances the heating mode when the flow is stopped. The lower limit compared with the hot water temperature detector 18 is around 50 ° C., and if the temperature detected by the hot water temperature detector 18 is equal to or lower than the lower limit value, the process proceeds to the next step of the heating mode when the flow is stopped. <S6>.
[0026]
  When the temperature detected by the hot water temperature detector 18 falls below the lower limit, first, the heating time set by the timer 25 is read <S7>. Next, the water temperature detected by the memory temperature detector 14 stored at the time of the previous hot water supply and the current water temperature are read <S8>. This is to determine how many times the feed water temperature is, and to correct the heating time and heating start temperature. When the water temperature is high, the time is short and the temperature is low, and when the water temperature is low, the time is The time for heating the heat exchanger 10 is corrected so that the temperature becomes longer and longer (S9).
[0027]
  And it is useful for supplying hot water having a temperature close to the set temperature as much as possible through the hot water supply pipe 12 at the time of re-heating. Next, the original solenoid valve 29 is opened <S11>, and simultaneously the timer 25 starts timing <S12>, and the opening of the gas proportional valve 28 is opened to a state where it is easy to ignite, and ignition is performed <S13. 〉.
[0028]
  Next, the ignition is confirmed, and the opening of the gas proportional valve 28 is reduced to the state of opening 2 <S14>. This opening degree corresponds to the minimum opening degree in a state where normal hot water supply is being performed, and even if heating is performed at this minimum opening degree, the load is small, so the temperature of the heat exchanger 10 gradually increases. Go.
[0029]
  In addition, when the minimum heating amount can be taken very low as a hot water supply device, a method of keeping the temperature detected by the hot water temperature detector 18 constant is also possible.
[0030]
  If the temperature detected by the hot water temperature detector 18 during the heating of the heat exchanger 10 shows an abnormal change gradient, it is judged that the air is caught in the heat exchanger 10 or the heating is abnormal, and the heating is stopped <S15. 〉. The lower limit, which is a predetermined value for determining the start of heating, is T1 = 50 ° C. The upper limit value T2 is set to 60 ° C. so as not to cause a burn even if a person touches it.
[0031]
  The heating time is 5 seconds in the standard state (water temperature 15 ° C., mixed water temperature 40 ° C.), and is corrected according to the water temperature as described above.
[0032]
  If the timer 25 exceeds a predetermined time (5 seconds or a correction value of 5 seconds), it is considered that the time is up and the stop operation is started <S16>. If the timer 25 fails or the capacity control of the gas burner 27 fails and the temperature detected by the hot water temperature detector 18 exceeds the upper limit (70 ° C.), the temperature of the original solenoid valve 29 is immediately given priority. <S17>.
[0033]
  Further, even when the temperature detected by the air detector 15 complementarily exceeds the upper limit (70 ° C.), the operation immediately enters a stop operation of closing the original solenoid valve 29 with temperature priority <S18>. When stopping the heating, the original solenoid valve 29 is closed <S19>, and after the heating is stopped, the combustion is continued until the temperature detected by the hot water temperature detector 18 falls below a predetermined lower limit value. It has stopped.
[0034]
  With the operation as described above, the temperature of hot water when hot water supply is stopped is maintained at a constant value, and an immediate hot water supply system is established. Therefore, assuming a general hot water supply device for home use, the conventional hot water supply device is a system with a pipe length of about 5 m, and it is normal that hot water is supplied about 15 seconds after the faucet of the terminal is twisted. ThingsThis reference example productCan be shortened to about 5 seconds.
[0035]
  The conventional hot water supply device takes about 10 seconds for the rise time of the hot water supply device itself due to the amount of retained water and the like, and it takes about 5 seconds to push out the retained water amount of the pipe.This reference example productThen, since the rise time of the hot water supply device itself can be shortened, only the time for pushing out the accumulated water in the pipe is required.
[0036]
  (Reference Example 2)
  In FIG.The thermistor 31 of the hot water temperature detector 15 is shared with the thermistor 38 of the hot water temperature detector 18 that detects the temperature in the vicinity of the heat exchanger 10. Since the air detection operation is activated only when the hot water supply operation is stopped, the operation of the hot water temperature detector 18 that measures the outlet temperature of the heat exchanger 10 during the hot water supply operation is not hindered. Is the same as when the thermistor 31 and the thermistor 38 are separate.
[0037]
  Further, since the air detection is performed by the thermistor 31 and the anti-freezing heater 37, it is only necessary to change the software contents of the controller 24 without increasing the number of parts compared to the conventional water heater. Therefore, by sharing the temperature detecting means and the thermistor of the air detecting means that are necessary for controlling the hot water temperature when supplying hot water, the number of thermistors can be reduced from two to one, and the cost can be reduced without degrading the performance. There is.
[0038]
  (Reference Example 3)
  FIG. 5 shows the air detection means 15 in the reference embodiment 3.The thermistor 31 and the antifreezing heater 37 are attached to the water pipe 36 so as to face each other at the same position of the water pipe near the outlet of the heat exchanger.
[0039]
  Therefore, the thermistor 31 and the antifreeze heater 37 can be arranged at the shortest distance, and the temperature rise in the water pipe 36 and the water pipe 36 due to the heating of the antifreeze heater 37 can be detected at high speed and significantly.Plus a short timeIn addition, there is an effect that the presence or absence of water in the water pipe can be accurately determined. Further, the thermistor 31 and the antifreeze heater 37 may be arranged close to each other, and the detection sensitivity of the temperature rise in the water pipe 36 by the thermistor 31 may be reduced so that the antifreeze heater 37 can be attached conveniently. The proximity means a position close to the cylindrical direction and the circumferential direction of the water pipe 36.
[0040]
  (Reference Example 4)
  Reference Example 4 is shown in FIGS.
[0041]
  First, after the reference temperature T0 is detected (1), the antifreeze heater is energized for a certain period of time to generate heat and immediately after the heat generation is stopped, the resistance value of the thermistor is measured to determine the temperature T1 after the heat generation is stopped (2) The discriminant value ΔT = T1−T0 is calculated, and when it is larger than the water / air discriminant value ΔTa determined in advance according to the characteristics of the appliance, it is judged as air, and when smaller, it is judged as water.
[0042]
  In principle, when water is present, the heat capacity around the thermistor is increased by the amount of water, and the amount of heat transferred from the antifreeze heater is absorbed by the water pipe and water, thereby decreasing the temperature rise of the thermistor. When air is present, the specific heat of air is significantly smaller than that of water, so the heat capacity around the thermistor is reduced, and the amount of heat transferred from the antifreeze heater is absorbed by the water pipe and air, resulting in an increase in the temperature rise of the thermistor. Yes.
[0043]
  FIG. 8 shows data obtained by the inventors' experiment. FIG. 5 is a plot of elapsed time and air engagement determination value ΔT (deg) when the anti-freezing heater is energized for 120 seconds and then naturally dissipates heat when there is water in the water pipe and when there is air. It can be seen that the air-engagement discrimination value ΔT is greater when air is present than when water is present.
[0044]
  In addition, even when there is water or air for a certain period after the energization of the antifreeze heater, the thermistor temperature continues to increase due to the remaining heat of the antifreeze heater and reaches a maximum value, and then the thermistor temperature decreases. The time until the thermistor temperature reaches its maximum value after energizing the antifreeze heater is faster for air than for water.Therefore,If it is determined that there is water, the process proceeds to the heating mode, heating by the burner is started, and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0045]
  The antifreezing heater energization heating time increases the heating time by increasing the antifreeze heater energization heating time as the temperature around the thermistor increases, thereby reducing the influence of the thermistor ambient temperature. Therefore, the air-engagement determination value ΔT can be calculated more accurately by changing the freeze-prevention heater energization heating time according to the temperature around the thermistor. In our experiments, the optimal anti-freezing heater energization heating time is set as shown in the following table.
[0046]
[Table 1]

[0047]
  (Reference Example 5)
  9 and 10Reference Example 5Indicates. FIG. 9 is a diagram showing the principle of air biting detection, and FIG. 10 is a flowchart of air biting detection. First, after detecting the reference temperature T0 (1), the anti-freezing heater is energized for a certain time to generate heat.
[0048]
  After de-energizing, the resistance value of the thermistor at the time when ΔL has passed is measured to obtain the thermistor temperature T1 (2), the air engagement discrimination value ΔT = T1−T0 is calculated, and the water previously determined according to the characteristics of the appliance If it is greater than the air discrimination value ΔTa, it is determined as air, and if it is smaller, it is determined as water.
[0049]
  In principle, even when there is water or air for a certain period of time after energization of the antifreeze heater, the air thermistor temperature will continue to rise due to the residual heat of the antifreeze heater and the maximum value with air will be judged as water / air judgment The difference in the discrimination value ΔT is most noticeable.
[0050]
  By determining the time until the temperature of the thermistor reaches the maximum value as ΔL when there is air due to this residual heat, the water / air discrimination can be made more accurate.
[0051]
  In the example of FIG. 8, when the energization time of the antifreeze heater is 120 seconds, ΔL = 60 seconds is an optimal setting value. If it is determined that there is water, the process proceeds to the heating mode, heating by the burner is started, and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0052]
  As in Example 4, the anti-freezing heater energization heating time is increased as the temperature around the thermistor increases, and the anti-freezing heater energization heating time is lengthened. The value ΔT can be calculated with high accuracy.
[0053]
  (Reference Example 6)
  Reference Example 6 is shown in FIGS.FIG. 11 is a diagram showing the principle of air biting detection, and FIG. 12 is a flowchart of air biting detection.
[0054]
  Thermistor temperature Ts is measured from the start of air bite detection (elapsed time t = 0), anti-freezing heat
The current heating is repeated n times until a preset time tp is exceeded, and then the temperature gradient during heating of the thermistor, that is, the thermistor temperature change rate dTs / dt is calculated from the measured relationship between Ts and t. The water / air discrimination thermistor that is determined in advance according to the characteristics of the instrument
If it is larger than the temperature-temporal change rate b, it is judged as air, and if it is smaller, it is judged as water.
[0055]
  In principle, when water is present, the heat capacity around the thermistor is increased by the amount of water, and the amount of heat transferred from the freeze prevention heater is absorbed by the water pipe and water, so that the temperature rise of the thermistor is reduced and the temperature gradient is reduced. When air is present, the specific heat of air is significantly smaller than that of water, so the heat capacity around the thermistor is reduced, and the amount of heat transferred from the antifreeze heater is absorbed by the water pipe and air, resulting in an increase in the temperature of the thermistor and an increase in temperature gradient. I use that.
[0056]
  If it is determined that there is water, the process proceeds to the heating mode, heating by the burner is started, and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0057]
  In addition, the freeze-heating heater energization heating time isReference Example 4As in the case of thermistor, the temperature of thermistor temperature change rate dTs / dt can be accurately calculated by increasing the heating temperature and increasing the heating temperature to reduce the influence of the thermistor ambient temperature as the ambient temperature increases. I have to.
[0058]
  (Reference Example 7)
  A seventh embodiment is shown in FIGS. FIG. 13 is a diagram showing the principle of air biting detection, and FIG. 14 is a flowchart of air biting detection.
[0059]
  First, the freeze prevention heater is energized for a certain time to generate heat. The measurement of the thermistor temperature Ts is started from the time when ΔL has elapsed after the power is turned off (elapsed time t = 0), and is repeated n times until a preset time tq is exceeded, and then the measured Ts and t From the relationship, the temperature gradient of the thermistor during heat dissipation, that is, the thermistor temperature change rate with time dTs / dt is calculated.
If the water-air discrimination thermistor temperature change rate c, which is determined according to the characteristics of the instrument, is larger than water, it is determined as water, and if it is smaller, it is determined as air.
[0060]
  In principleIsAfter energizing the anti-freeze heater, the thermistor temperature continues to rise due to the residual heat of the anti-freeze heater even if there is water or air. Continue to reach the maximum value.
[0061]
  That meansBy setting ΔL to the time until the temperature of the thermistor reaches the maximum value when there is residual heat and air, the temperature gradient after the passage of ΔL is positive when water is present, and negative when air is present. Therefore, water / air discrimination can be made more accurate.
[0062]
  If it is determined that there is water, the process proceeds to the heating mode, heating by the burner is started, and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0063]
  In addition, the freeze-heating heater energization heating time isReference Example 4As in the case of thermistor, the temperature of thermistor temperature change rate dTs / dt can be accurately calculated by increasing the heating temperature and increasing the heating temperature to reduce the influence of the thermistor ambient temperature as the ambient temperature increases. I have to.
[0064]
  Based on each reference embodiment, the embodiment will be described below.
[0065]
  (Example 1)
  15 and 16,Thermistor temperature Ts is measured from the start of the air bite detection (elapsed time t = 0), and the antifreeze heater energization heating is repeated n times until a preset time tr is exceeded, and then the relationship between the measured Ts and t is determined. The heat storage heat amount at the time of heating the thermistor is obtained as an integral value ∫tr0dTs · dt, and when it is larger than the preset water-air discrimination thermistor heat storage heat amount e, it is determined as air, and when it is smaller, it is determined as water.
[0066]
  In principle, when there is water, the heat capacity around the thermistor is increased by the amount of water, the amount of heat transferred from the antifreeze heater is absorbed by the water pipe and water, the temperature rise of the thermistor is reduced, and the stored heat quantity ∫tr0dTs · dt is small. Become.
[0067]
  When air is present, the specific heat of air is significantly smaller than that of water, so the heat capacity around the thermistor is reduced, and the amount of heat transferred from the antifreeze heater is absorbed by the water pipe and air. As a result, the temperature rise of the thermistor increases and the stored heat quantity ∫tr0dTs · The fact that dt is increased is used.
[0068]
  If it is determined that there is water, the process proceeds to the heating mode, heating by the burner is started, and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0069]
  In addition, the freeze-heating heater energization heating time isReference Example 4In the same way as the temperature of the thermistor increases, the energization heating time of the antifreeze heater is lengthened and the effect of the thermistor ambient temperature is reduced by raising the heating temperature so that the thermistor heat storage amount 熱 tr0dTs · dt can be calculated accurately. ing.
[0070]
  (Example 2)
  17 and 18, first,The anti-freezing heater is energized for a certain time to generate heat. After turning off the power, measurement of the thermistor temperature Ts is started (elapsed time t = 0) and repeated n times until the preset time ts is exceeded, and then the thermistor temperature is determined from the relationship between the measured Ts and t. The amount of heat stored during heat dissipation and the integral value ∫ts0dTs · dt are obtained. If the water-air discrimination thermistor heat storage heat amount f is larger than the preset value, air is determined, and if it is smaller, water is determined.
[0071]
  If it is determined that there is water, the process proceeds to the heating mode, heating by the burner is started, and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0072]
  As in Example 4, the antifreeze heater energization heating time is increased by increasing the antifreeze heater energization heating time as the temperature around the thermistor increases, and by increasing the heating temperature, the influence of the thermistor ambient temperature is reduced, and thermistor heat storage is performed. The heat quantity ∫ts0dTs · dt can be calculated with high accuracy.
[0073]
  (Example 3)
  19 and 20, first, freezingThe prevention heater is energized to generate heat, and detection of the thermistor temperature Ts is repeated for a fixed time ΔF before and after the end of heat generation. In the example of FIG. 19, 1/2 · ΔF before the freeze prevention heater energization end time is at the start of the thermistor temperature measurement (t = 0), and the remaining thermistor measurement time 1/2 · ΔF is after the thermistor energization end time.
[0074]
  After a certain time ΔF has elapsed, the heat storage heat amount of the thermistor is obtained as an integral value ∫ΔF0dTs · dt from the measurement results of the thermistor temperature Ts and the elapsed time t, and compared with a preset water / air discrimination thermistor heat storage heat amount g. It is determined that it is bitten, and if it is small, it is determined that there is water.
[0075]
  In principleFusion of Example 1 and Example 2Since the presence or absence of water is determined based on the amount of heat stored in the thermistor only before and after the end of the thermistor heating with the most severe temperature change, more accurate determination can be made.
[0076]
  If it is determined that there is water, the process proceeds to the heating mode, heating by the burner is started, and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0077]
  As in Reference Example 4, the anti-freezing heater energization heating time is increased as the temperature around the thermistor increases, and the anti-freezing heater energization heating time is increased, and the effect of the thermistor ambient temperature is reduced by increasing the heating temperature. The stored heat quantity ∫ΔF0dTs · dt can be calculated with high accuracy.
[0078]
  As described above, the significance of the hot water supply apparatus of the reference example and the example is as follows.
[0079]
  (1) When the hot water supply is stopped, the flow detection means detects that the flow of water to the heat exchanger has stopped, and when the temperature detected by the temperature detection means falls below a predetermined temperature, heating is performed by the heating adjustment means. means Heating of the heat exchanger is started, and when the predetermined time or temperature is reached, the heating is stopped to prevent the heat exchanger from being cooled when hot water supply is stopped. The time for heating the retained water can be saved, and the hot water supply at the terminal at the time of hot water supply can be performed quickly with only the hot water supply apparatus main body. In addition, when the air detector using an anti-freeze heater detects air jamming, the heat exchanger is not heated by the heating means, so at the initial installation or after draining water to prevent freezing. Heating is performed when air is in the heat exchanger, and the heat exchanger can be prevented from being blown to improve safety and maintain durability.
[0080]
  (2) By sharing the temperature detection means for detecting the temperature in the vicinity of the heat exchanger and the thermistor of the air detection means, there is an effect that the number of thermistors can be reduced from two to one and the cost can be reduced. In addition, since the air detection operation is activated only when the hot water supply operation is stopped, the function of the temperature detection device and the air detection are not disturbed without interfering with the operation of the temperature detection device that measures the outlet temperature of the heat exchanger during the hot water supply operation. The functions of the means can be made compatible.
[0081]
  (3) The thermistor and antifreeze heater are mounted opposite to each other in the same position on the water pipe near the heat exchanger outlet, so that the thermistor and antifreeze heater can be placed at the shortest distance, and the antifreeze heater is heated. The temperature rise in the water pipe / water pipe due to can be detected at high speed and with a thermistor. Therefore, the presence / absence of water in the water pipe can be determined with high accuracy in a short time, and the heat exchanger can be prevented from being blown.
[0082]
  (4) After the air detection is started, the air detection means uses a thermistor to set the reference temperature T 0 After measurement, the anti-freezing heater is energized for a certain period of time to generate heat and immediately after the heat generation stops 1 Measured temperature after heat generation T 1 And reference temperature T 0 The difference ΔT from water is a preset water / air determination temperature difference ΔT a Compared with ΔT> ΔT a In the case of, it is determined that the air is in the air-engaged state and ΔT ≦ ΔT a In this case, since it is determined that there is water, the presence / absence of water in the heat exchanger is surely determined. If it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0083]
  (5) After the air detection is started, the air detection means uses a thermistor to set the reference temperature T 0 After measurement, the anti-freezing heater is energized for a certain period of time to generate heat and after the heat generation has stopped, after a certain period of time ΔL has elapsed, the post-heating temperature T 1 Measured temperature after heat generation T 1 And reference temperature T 0 The difference ΔT from water is a preset water / air determination temperature difference ΔT a Compared with ΔT> ΔT a In the case of, it is determined that the air is in the air-engaged state and ΔT ≦ ΔT a In this case, since it is determined that there is water, the presence / absence of water in the heat exchanger is surely determined. If it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0084]
  (6) The air detection means starts energization of the antifreeze heater after the start of air detection, and the thermistor temperature T. s Thermistor temperature T s And the measurement result of elapsed time t, thermistor temperature change rate dT s / Dt is obtained and compared with a preset water / air discrimination thermistor temperature / time change rate b dT s If / dt> b, it is determined that the air is in the air-engaged state and dT s If / dt ≦ b, it is determined that there is water, so the presence or absence of water in the heat exchanger is reliably determined. If it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started. Enter. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0085]
  (7) The air detection means energizes the anti-freezing heater for a certain period of time after starting the air detection, stops the heat generation, and after a certain period of time ΔL has elapsed, the thermistor temperature T s Thermistor temperature T s And the measurement result of elapsed time t, thermistor temperature change rate dT s Find / dt in advance Specified water / air discrimination thermistor temperature change rate over time c Compared to dT s / Dt ≦ c In the case of dT s / Dt> c In this case, since it is determined that there is water, the presence / absence of water in the heat exchanger is surely determined. If it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0086]
  (8) The air detection means starts the air detection, energizes the antifreeze heater, and thermistor temperature T. s Thermistor temperature T s And the measurement result of elapsed time t t0 dT s ・ Determining dt and preset water / air discrimination thermistor heat storage e Compare with ∫ t0 dT s ・ Dt> e In the case of t0 dT s ・ Dt ≦ e In this case, since it is determined that there is water, the presence / absence of water in the heat exchanger is surely determined. If it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0087]
  (9) The air detecting means energizes the anti-freezing heater for a certain period of time after starting the air detection, stops the heat generation, and then thermistor temperature T s Thermistor temperature T s And the measurement result of elapsed time t t0 dT s ・ Determining dt and preset water / air discrimination thermistor heat storage f Compare with ∫ t0 dT s ・ Dt> f In the case of t0 dT s ・ Dt ≦ f In this case, since it is determined that there is water, the presence / absence of water in the heat exchanger is surely determined. If it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0088]
  (10) The air detecting means energizes the anti-freezing heater for a certain period of time after starting the air detection to generate heat and thermistor temperature T for a certain period ΔF before and after the end of the heat generation. s Thermistor temperature T s And the measurement result of elapsed time t F0 dT s ・ Determining dt and preset water / air discrimination thermistor heat storage g Compared to ∫Δ F0 dT s ・ Dt> g In the case of 判定 Δ F0 dT s ・ Dt ≦ g In this case, since it is determined that there is water, the presence / absence of water in the heat exchanger is surely determined. If it is determined that there is water, the process proceeds to the heating mode and heating by the burner is started and the immediate hot water system is entered. When it is determined that the air is caught, the process proceeds to the heating stop mode, and the heating by the burner is stopped, so that the heat exchanger can be prevented from being blown.
[0089]
【The invention's effect】
  As described above, the hot water supply apparatus of the present invention prevents the heat exchanger from being cooled when hot water supply is stopped, enables quick supply of hot water to the terminal at the time of hot water supply during hot water supply, and air detection. When the air catching is detected by the heat exchanger, the operation of starting heating of the heat exchanger by the heating means is not performed, so that the heat exchanger can be reliably prevented from being blown.
[Brief description of the drawings]
FIG. 1 of the present inventionReference Example 1Diagram of hot water supply system in Japan
FIG. 2 is a partial cross-sectional view showing a mounting state of the thermistor of the water heater
FIG. 3 is a flowchart of the main operation of the water heater.
FIG. 4 of the present inventionReference Example 2Diagram of hot water supply system in Japan
FIG. 5 shows the present invention.Reference Example 3Notched cross-sectional view of an air detector used in a hot water supply system
FIG. 6 of the present inventionReference Example 4Explaining the main part operation of the hot water supply device in
FIG. 7 is a flowchart of the main operation of the hot water supply apparatus.
FIG. 8 is a diagram for explaining the principle of the hot water supply apparatus based on experimental data.
FIG. 9 shows the present invention.Reference Example 5Explaining the main part operation of the hot water supply device in
FIG. 10 is a flowchart of the main operation of the hot water supply apparatus.
FIG. 11 shows the present invention.Reference Example 6Explaining the main part operation of the hot water supply device in
FIG. 12 is a flowchart of the main operation of the hot water supply apparatus.
FIG. 13 shows the present invention.Reference Example 7Explaining the main part operation of the hot water supply device in
FIG. 14 is a flowchart of the main operation of the hot water supply apparatus.
FIG. 15 shows the present invention.Example 1Explaining the main part operation of the hot water supply device in
FIG. 16 is a flowchart of the main operation of the hot water supply apparatus.
FIG. 17 shows the present invention.Example 2Explaining the main part operation of the hot water supply device in
FIG. 18 is a flowchart of the main operation of the hot water supply apparatus.
FIG. 19 shows the present invention.Example 3Explaining the main part operation of the hot water supply device in
FIG. 20 is a flowchart of the main operation of the hot water supply apparatus.
FIG. 21 is a configuration diagram of a conventional hot water supply apparatus.
[Explanation of symbols]
  10 Heat exchanger
  11 Water supply pipe
  12 Hot water supply pipe
  13 Water detector
  15 Air detector
  18 Hot water temperature detector (temperature detection means)
  24 Controller
  26 Control unit at stop
  27 Gas Burner
  28 Gas proportional valve (heating control means)
  29 original solenoid valve
  31 Thermistor (Air detection means)
  37 Anti-freeze heater
  38 Thermistor (temperature detection means)

Claims

A heat exchanger in which a water supply pipe and a hot water supply pipe are connected, a heating means for heating the heat exchanger, a heating adjustment means for adjusting the heating means, and a temperature detection means for detecting the temperature in the vicinity of the heat exchanger Flow detection means for detecting the flow of water, air detection means for detecting air biting in the heat exchanger using a thermistor and an antifreeze heater provided in the vicinity of the outlet of the heat exchanger, and the flow detection means When the temperature detected by the temperature detection means is not more than a predetermined temperature when the flow of water is not detected in the control of the heating adjustment means to start heating the heat exchanger by the heating means, The heating is stopped when a preset time or temperature is reached, and when the air detection means detects air biting, it includes a stop time control unit that does not heat the heat exchanger by the heating means. The above Gas detection means, after air detection start energization of the antifreeze heater, repeated detection of the thermistor temperature T s, the integral value heat storage heat of the thermistor from the measurement results of the thermistor temperature T s and the elapsed time t ∫ t0 dT s · obtained as dt is compared with a preset water air discriminated thermistor thermal storage heat e, determines that the air biting state for ∫ t0 dT s · dt> e , the water in the case of ∫ t0 dT s · dt ≦ e A hot water supply device that is determined to be present .

A heat exchanger in which a water supply pipe and a hot water supply pipe are connected, a heating means for heating the heat exchanger, a heating adjustment means for adjusting the heating means, and a temperature detection means for detecting the temperature in the vicinity of the heat exchanger Flow detection means for detecting the flow of water, air detection means for detecting air biting in the heat exchanger using a thermistor and an antifreeze heater provided in the vicinity of the outlet of the heat exchanger, and the flow detection means When the temperature detected by the temperature detection means is not more than a predetermined temperature when the flow of water is not detected in the control of the heating adjustment means to start heating the heat exchanger by the heating means, The heating is stopped when a preset time or temperature is reached, and when the air detection means detects air biting, it includes a stop time control unit that does not heat the heat exchanger by the heating means. The above Gas detection means, after air detection start, after the heat generation stop is performed for a predetermined time energizing the antifreeze heater, repeated detection of the thermistor temperature T s, the thermal storage of the thermistor from the measurement result of the thermistor temperature T s and the elapsed time t The amount of heat is obtained as an integral value ∫ t0 dT s · dt, and compared with a preset water / air discrimination thermistor heat storage heat amount f , if ∫ t0 dT s · dt> f , it is determined that the air is engaged, and ∫ t0 dT s A hot water supply apparatus that determines that there is water when dt ≦ f .

A heat exchanger in which a water supply pipe and a hot water supply pipe are connected, a heating means for heating the heat exchanger, a heating adjustment means for adjusting the heating means, and a temperature detection means for detecting the temperature in the vicinity of the heat exchanger Flow detection means for detecting the flow of water, air detection means for detecting air biting in the heat exchanger using a thermistor and an antifreeze heater provided in the vicinity of the outlet of the heat exchanger, and the flow detection means When the temperature detected by the temperature detection means is not more than a predetermined temperature when the flow of water is not detected in the control of the heating adjustment means to start heating the heat exchanger by the heating means, The heating is stopped when a preset time or temperature is reached, and when the air detection means detects air biting, it includes a stop time control unit that does not heat the heat exchanger by the heating means. The above Gas detection means, after air detection start, heat is generated by performing a predetermined time energizing the antifreeze heater, repeated detection of the thermistor temperature T s for a predetermined time ΔF of the heating before and after completion, the thermistor temperature T s and the elapsed time t The heat storage heat quantity of the thermistor is obtained as an integral value ∫Δ F0 dT s · dt from the measurement result of the above, and compared with a preset water / air discrimination thermistor heat storage heat amount g, and if ∫Δ F0 dT s · dt> g , the air engagement A hot water supply device that is determined to be in a state and is determined to have water when ∫ΔF 0 dT s · dt ≦ g .