JP3836953B2

JP3836953B2 - Water heater

Info

Publication number: JP3836953B2
Application number: JP19070597A
Authority: JP
Inventors: 敏宏小林
Original assignee: パロマ工業株式会社
Priority date: 1997-06-30
Filing date: 1997-06-30
Publication date: 2006-10-25
Anticipated expiration: 2017-06-30
Also published as: JPH1123059A

Description

【０００１】
【発明の属する技術分野】
本発明は給湯器に関し、詳しくはバイパスミキシング方式の給湯器に関する。
【０００２】
【従来の技術】
従来から、熱交換器をバイパスするバイパス路を備えた給湯器が知られている。例えば図８に示すものでは、給水路１と出湯路２とが接続される熱交換器３と、熱交換器３を流れる水を加熱するためのバーナ４と、熱交換器３をバイパスするバイパス路５と、燃焼制御を司るコントローラ６とを備える。そして、給水路１のバイパス路５との分岐部より上流側には入水流量を検出する流量センサ１ａが設けられ、バイパス路５との分岐部より下流側には熱交換器３を流れる水の最大流量を制限する水温補正式水ガバナ１ｂが設けられる。また出湯路２のバイパス路５との合流部より下流側には混合後の湯温を検出する出湯温センサ２ａが設けられる。更にバイパス路５にはバイパス路５を流れる水の最大流量を制限する水ガバナ５ａと、流路を開閉するバイパス弁５ｂとが設けられる。また、コントローラ６には設定温度を設定するためのリモコン７が接続される。そして、低温設定時にはバイパス弁５ｂを開弁して給水路１から供給された水を熱交換器３側とバイパス路５側とに分流させ、熱交換器３で加熱した湯とバイパス路５を通過させた水とを混合して出湯することで、熱交換器３での湯の温度を実際の出湯温度より高くしてドレン（結露）の発生を抑え、熱交換器３の腐食を防止する。また高温設定時にはバイパス弁５ｂを閉弁して給水路１から供給された水を全て熱交換器３側に流すことで、熱交換器３での湯の沸騰を防止する。
【０００３】
また、バイパス路５に水ガバナ５ａを設けてバイパス路５を流れる水の最大流量を制限すると共に、給水路１のバイパス路５との分岐部より下流側にも水温補正式水ガバナ１ｂを設けて熱交換器３を流れる水の最大流量を制限している。このように水の最大流量を制限することで、出湯量が器具の能力を越えてしまうことにより出湯温度を設定温度まで上昇させることができないといった不具合を防いでいる。
【０００４】
更に、このように分岐後の流路にそれぞれ水ガバナ１ｂ，５ａを設けることにより、バイパス弁５ｂの開弁時の最大出湯量がバイパス弁５ｂの閉弁時の最大出湯量に比べて増加する。設定温度での出湯が可能な湯量は設定温度が低いほど大きくなることから、出湯量を単に一定値に制限する場合に比べ低温の湯を大量に使用することができるため使い勝手が良い。
【０００５】
設定温度での出湯可能な湯量は入水温度によっても変化し、水温が低いほど小さくなる。上述した例では熱交換器３側の流量制限に水温補正式のものを用いているため、入水温度が低い場合には流量を減少させることができる。
尚、上述したような例は、実開平１−１４８５５８に開示されている。
【０００６】
【発明が解決しようとする課題】
ところで、水温補正式水ガバナは一般に形状記憶合金製ばね（以下、ＳＭＡばねと呼ぶ）を用いて構成されており、ＳＭＡばねのばね荷重が温度により変化する性質を利用して制限流量を可変している。ここで、ＳＭＡばねのばね荷重の変化率はそれほど高くすることができないため、制限流量の変化率も制限されてしまうといった問題があった。上述した構成では、入水温度が変化してもバイパス路５を流れる水の制限流量は一定であるため、バイパス弁５ｂを開弁した状態での出湯量の制限流量を十分に変化させることができず、水温の違いに対して出湯性能を十分に維持することができなかった。かといって、バイパス側の水ガバナも水温補正式にすると、ＳＭＡばね自体が高価であるため器具のコストが高くなってしまうといった問題があった。
しかもこのような構成では、入水温度が低くなるほどバイパス率が高くなって沸騰しやすい欠点がある。
本発明の給湯器は上記課題を解決し、簡単な構成により入水温度による補正量を大きくすることを目的とする。
【０００７】
【課題を解決するための手段】
上記課題を解決する本発明の請求項１記載の給湯器は、
上流端と下流端とに給水路と出湯路とがそれぞれ接続される熱交換器と、
この熱交換器を加熱するガスバーナと、
上記給水路の途中から分岐され上記出湯路の途中で合流されて上記熱交換器をバイパスするバイパス路と、
このバイパス路に設けられるバイパス弁を有し、
設定温度が熱交換器のドレン限界温度未満の場合には、給水路からバイパス路への分流比率が高バイパス率になるように上記バイパス弁を制御する一方、設定温度がドレン限界温度以上の場合には、給水路からバイパス路への分流比率が上記高バイパス率よりも低比率の低バイパス率となるように上記バイパス弁を制御する給湯器において、
上記給水路のバイパス路への分岐点から、上記出湯路のバイパス路との合流点との間に熱交換器への流量を制限する熱交換器用水ガバナを設け、
上記給水路のバイパス路への分岐点よりも上流側に、水温温度に応じて最大流量を変化させる入水温度補正機能付きの全流量水ガバナを設けることを要旨とする。
【０００８】
上記課題を解決する本発明の請求項２記載の給湯器は、請求項１記載の給湯器において、
上記バイパス弁を電磁弁とし、この電磁弁のＯＮ−ＯＦＦ制御により上記バイパス率の切り替えを行なうことを要旨とする。
【０００９】
上記課題を解決する本発明の請求項３記載の給湯器は、請求項１記載の給湯器において、
上記バイパス弁を開度が調整可能な開度調節弁とし、熱交換器出口の湯温を検出する出口温度検出手段を設けるとともに、高バイパス率時で各水ガバナが最大流量に達していない状態においては、上記出口温度検出手段による検出結果に基づき、熱交換器出口の湯温が上記ドレン限界温度と沸騰上限温度との間の温度に保持されるように上記開度調整弁の開度を調節することを要旨とする。
【００１０】
上記構成を有する本発明の請求項１記載の給湯器は、設定温度に基づき、バイパス弁が制御されて熱交換器をバイパスするバイパス率が切り替えられる。そして、バイパス路への分流比率が高い高バイパス率時には入水温度補正機能付きの全流量用水ガバナにて主に流量制限がなされ、バイパス路への分流比率が高バイパス率よりも低い低バイパス率時においては、熱交換器用水ガバナにて主に流量制限がなされる。このような構成により、入水温度補正機能付きの全流量用水ガバナによる入水温度に応じた制限流量の変化率と同じ割合で高バイパス率時の最大出湯量を補正することができるため、入水温度による最大出湯量の補正量を大きくすることができる。
【００１１】
上記構成を有する本発明の請求項２記載の給湯器は、バイパス率の切り換えを電磁弁のＯＮ−ＯＦＦにより行なうため、構造を簡単にしてコストを低減することができる。
【００１２】
上記構成を有する本発明の請求項３記載の給湯器は、熱交換器出口の湯温度に基づき、開度調節弁の開度を調節することで熱交換器出口の湯温が上記ドレン限界温度と沸騰上限温度との間の温度に保持する。よって、沸騰やドレンの発生を防止することができる。
【００１３】
【発明の実施の形態】
以上説明した本発明の構成・作用を一層明らかにするために、以下本発明の給湯器の好適な実施例について説明する。
図１は、本発明の第１実施例としての給湯器の概略構成図である。この給湯器は、給水路１０と出湯路２０とが接続される熱交換器３０と、熱交換器３０を流れる水を加熱するためのバーナ４０と、熱交換器３０をバイパスするバイパス路５０と、燃焼制御を司るコントローラ６０とを備える。給水路１０のバイパス路５０との分岐部Ａより上流側には、入水流量を検出する流量センサ１１と、器具に供給される水の最大流量を制限する第１水ガバナ８０とが設けられ、バイパス路５０との分岐部Ａより下流側には、熱交換器３０を流れる水の最大流量を制限する第２水ガバナ１２が設けられる。また出湯路２０のバイパス路５０との合流部Ｂより上流側には、熱交換器出口での湯温を検出する出口温センサ２１が設けられ、バイパス路５０との合流部より下流側には、混合後の湯温を検出する出湯温センサ２２が設けられる。更にバイパス路５０には、流路を開閉する電磁弁５１と、分岐部Ａで分岐する流量比を所定の比率に保つオリフィス５２とが設けられる。
【００１４】
コントローラ６０は、図示しない周知の算術論理演算回路を構成するＣＰＵ，ＲＡＭ，ＲＯＭと、各種センサからの信号を入力する入力インタフェースと、各種アクチュエータに駆動信号を出力する出力インタフェース等から構成される。またコントローラ６０には、設定温度の設定といった外部操作を行なうための操作スイッチ類と設定温度等を表示するための表示器とを備えたリモコン７０が接続される。
【００１５】
リモコン７０では、３８〜４６℃の低温域と、４８，５０，５５，６０℃の高温域との範囲で設定温度を設定する。そしてコントローラ６０は、設定温度が低温域の温度に設定された状態での出湯動作時には電磁弁５１を開弁し、高温域の温度に設定された状態での出湯動作時には電磁弁５１を閉弁するように制御することで、低温の湯の出湯時にも熱交換器３０で加熱される湯を高温に保ってドレンの発生を防止すると共に、高温の湯の出湯時には熱交換器３０で加熱される湯が沸騰しないようにする。ここで、バイパス路５０に設けられたオリフィス５２により、器具に供給された水の４０％をバイパス路５０に分流させるような流路抵抗をつけているため、電磁弁５１の開弁時に器具に供給される水の流量（以下、トータル流量と呼ぶ）及び熱交換器３０に供給される水の流量（以下、熱交換器流量と呼ぶ）がそれぞれ第１制限流量，第２制限流量に達していない状態では、熱交換器流量とバイパス路５０を流れる流量（以下、バイパス流量と呼ぶ）との比が６：４になる。
【００１６】
ここで、熱交換器３０の出口温度とバイパス率との関係について図２のグラフを用いて説明する。熱交換器３０の出口温度の沸騰限界を８５℃，ドレン限界を４８℃とすると、出口温度を４８℃以上８５℃以下の範囲に保つ必要がある。設定温度が４８〜６０℃の高温域では、電磁弁５１を閉弁することで熱交換器３０の出口温度を設定温度と等しくして、ドレン限界以上沸騰限界以下に保つことができる。一方、設定温度が３８〜４６℃の低温域では、バイパスさせずに出湯しようとすると、熱交換器３０の出口温度がドレン限界を下回ってしまう。そのため、電磁弁５１を開弁して４０％の水をバイパスさせることで、熱交換器３０の出口温度を設定温度より高くする。その結果、設定温度が低温域の最低温度である３８℃でしかも水温が２０℃と高い場合であっても熱交換器３０の出口温度をドレン限界である４８℃以上にすることができ、また設定温度が低温域の最高温度である４６℃でしかも水温が１０℃と低い場合であっても熱交換器３０の出口温度を沸騰限界である８５℃以下にすることができる。
【００１７】
また、コントローラ６０は出湯温センサ２２により検出する出湯温度を設定温度に近づけるように、バーナ４０へのガス供給路に設けられる比例弁（図示せず）によりガス供給量を調節して燃焼量をコントロールするといった出湯温制御を行なう。その際、バーナ４０の最大燃焼量で熱交換器３０を流れる水に与える熱量は、５００kcal/minである。
尚、電磁弁５１の閉弁時には出口温センサ２１の検出温度を設定温度に近づけるように出湯温制御してもよい。出口温センサ２１は出湯温センサ２２に比べより熱交換器側に近い位置に設けられるため、検出温度のフィードバックをはやくして出湯温制御の性能をより高くすることができる。
【００１８】
また、コントローラ６０は、設定温度が低温域の状態即ち電磁弁５１へ開弁指令を出力している状態であるにもかかわらず、出湯動作中の出口温センサ２１と出湯温センサ２２との検出温度にほとんど差がないと判断した場合には、電磁弁５１が開弁しない状態の故障が発生したと判断する。同様に、設定温度が高温域の状態即ち電磁弁５１へ閉弁指令を出力している状態であるにもかかわらず、出湯動作中の出口温センサ２１と出湯温センサ２２との検出温度の差が大きいと判断した場合には、電磁弁５１が閉弁しない状態の故障が発生したと判断する。
【００１９】
第１水ガバナ８０は、トータル流量を制限するために設けられるもので、図３に示すように、給水路１０と直列に連結される固定弁体８１と、固定弁体８１の内壁面にシール部材８２を介して密着された状態で可動自在に設けられる可動弁体８３と、可動弁体８３を水の圧力に抗して付勢する形状記憶合金製のＳＭＡばね８４とからなる。
【００２０】
ＳＭＡばね８４は、入水温度が高くなるにつれてばね荷重が増大し、入水温度が低くなるにつれてばね荷重が減少する。そのため、入水温度に応じて制限する最大流量（以下、第１制限流量）を変化させることができる。本実施例では、第１制限流量を入水温度が１０℃の時には１６l/min ，入水温度が２０℃の時には２４l/min となるように設定している。ここで、ばね荷重の変化により流量を変化させるには、その流量変化率を２乗した分ばね荷重を変化させる必要があり、入水温度が１０℃から２０℃に変化する間に第１制限流量を１．５倍に変化させるため、その温度変化でばね荷重が１．５²＝２．２５倍変化するＳＭＡばね８４を使用する。
【００２１】
この第１制限流量は電磁弁５１を開弁した状態、即ち設定温度が３８〜４６℃の低温域で設定されている場合の最大出湯量である。本実施例では、低温域の設定温度で４０℃の湯の使用頻度が高いことに着目して、４０℃の湯が最大限に出湯可能となるような第１制限流量に設定されている。
水温が１０℃の場合には、第１制限流量を１６l/min に制限するため、
（４０℃−１０℃）×１６l/min ＝４８０kcal/min
４８０kcal/min／５００kcal/min＝０．９６
となり、最大燃焼時の９６％の能力を発揮する。
また、水温が２０℃の場合には、第１制限流量を２４l/min に制限するため、
（４０℃−２０℃）×２４l/min ＝４８０kcal/min
４８０kcal/min／５００kcal/min＝０．９６
となり、最大燃焼時の９６％の能力を発揮する。
このように、設定温度が４０℃の時にほぼ最大能力を発揮するようにすることで、４０℃の湯を大量に出湯することができる。
【００２２】
第２水ガバナ２１は、熱交換器流量を制限するために設けられるもので、入水温度に関係なく最大流量（以下、第２制限流量）を１２l/min となるように設定されている。この第２制限流量は電磁弁５１を閉弁した状態、即ち設定温度が４８〜６０℃の高温域に設定されている場合の最大出湯量である。本実施例では、第２制限流量を１２l/min に制限するため、最大流量の水を最大燃焼量で加熱した場合、
５００kcal/min／１２l/min ＝４１．７deg
温度上昇させることができ、給湯栓を最大に開いても水温が１０℃の場合には５１．７℃，水温が２０℃の場合には６１．７℃の湯が出湯可能となる。
【００２３】
このように、トータル流量を制限する第１水ガバナ８０により水温補正することで、分岐後の流量を制限する水ガバナにより水温補正する場合に比べ、水温補正によるトータル流量の補正量を大きくすることができる。例えば、従来例（図８）で示した給湯器において、水温補正式水ガバナ１ｂにより熱交換器流量を水温２０℃の時に１２l/min に制限する場合、バイパス弁５ｂの開弁時に水温補正式水ガバナ１ｂで本実施例と同じ補正量（８l/min ）を得ようとすると、水温が２０℃→１０℃に変化する間に制限流量を１２l/min →４l/min まで変化させる必要がある。このように水温が１０℃から２０℃に変化する間に流量を３倍変化させるには、ばね荷重が３² ＝９倍に変化するＳＭＡばねを使用しなければならないことになるが、このように変化するＳＭＡばねを実現することは困難である。
【００２４】
以上説明したように、第１実施例の給湯器によれば、トータル流量を制限する第１水ガバナ８０により水温補正するといった単純な構成により、入水温度による制限流量の変化を大きくすることができるため、入水温度に最適な出湯量に変化させて出湯性能を維持することができる。しかも、水温補正する水ガバナは１つでよいため低コストで実現できる。また、低温域での出湯量と高温域での出湯量とを別々のガバナにより制限することで、高温域に比べて大量の出湯が可能な低温域での出湯量を大きくすることができるため、使い勝手がよい。しかも、水ガバナを２つ設けるだけの簡単な構成であるため低コストで実現できる。
【００２５】
尚、第２水ガバナは熱交換器３０を通過する水の最大流量を制限すればよいため、出湯路２０のバイパス路５０との合流部Ｂより上流側に設けてもよい。
【００２６】
次に、本発明の第２実施例について説明する。図４は第２実施例としての給湯器の概略構成図である。基本的な構成は第１実施例（図１）と同一であるが、電磁弁５１の代りに機能の異なる電磁弁５３を設けた点で異なる。その他重複する構成については、同一符号を付してその説明を省略する。
【００２７】
電磁弁５３は、閉弁時にも流路を完全に閉じない構造となっている。そして、電磁弁５３開弁時のバイパス率が５０％となるようにオリフィス５２により流路抵抗がつけられている。また、閉弁時にはバイパス率が１５％となるような流路抵抗がつけられている。
【００２８】
ここで、このような構造の電磁弁５３を用いる理由について説明する。
第１の理由は、熱交換器３０でのドレン及び沸騰を確実に防止するためである。第１実施例では図２のグラフに示したように、熱交換器３０の出口温度をドレン限界と沸騰限界との間に保つため、設定温度が３８〜４６℃の低温域では４０％の水をバイパスさせて、設定温度が３８℃で水温が２０℃といったドレンの発生しやすい条件でも熱交換器３０の出口温度を約５０℃まで上昇させることができるが、入水温度が更に高温になるとドレン限界である４８℃を下回ってしまう恐れがある。このような場合にもドレンの発生を防ぐためには、バイパス率を更に高くする必要がある。そこで図５に示すように電磁弁５３の開弁時にバイパス率が５０％となるように設定すると、入水温度が高温となってもドレンの発生を防ぐことができるが、設定温度が４６℃で水温が１０℃の場合には熱交換器３０の出口温度が約８２℃まで上昇し、水温が更に低温になると沸騰限界である８５℃を上回ってしまう恐れがある。かといってバイパス流路を遮断すると、熱交換器３０の出口温度は設定温度である４６℃となってしまい、ドレン限界である４８℃を下回ってしまう。
【００２９】
そこで、電磁弁５３を閉弁してもバイパス流路が完全に遮断されず、バイパス率を１５％に低下させる構成とすることで、設定温度が４６℃の場合にも熱交換器３０の出口温度をドレン限界以上にすることができる。このように、電磁弁５３の開弁時に沸騰する恐れのある場合には電磁弁５３を閉弁してバイパス率を低下させることで、水温が大きく変化する状況下でも熱交換器３０の出口温度を常にドレン限界以上沸騰限界以下に保つことができる。また、高温域での最高温度である６０℃に設定された場合にも、バイパス率が１５％と低いため、熱交換器３０の出口温度を約７０℃に抑えることができ、沸騰を防止することができる。
【００３０】
第２の理由は、器具の流路抵抗を減らすためである。供給水圧の低い条件下では十分な出湯量を得るため、器具の流路抵抗を減らす必要がある。ここで、熱交換器３０側の流路抵抗を減らそうとした場合、水の流路を形成するパイプの径を大きくする必要があるが、熱交換器側のパイプは熱効率を高くする目的のため長く曲がりくねった形状であり、このパイプ径を変更しようとするとコストが大幅に上がってしまう。本実施例では、バイパス路５０を流れる流量を全体的に増やすため、低コストで器具の流路抵抗を減らすことができる。
【００３１】
以上説明したように、第２実施例の給湯器によれば、電磁弁５３を閉弁した際にもバイパス流路を完全に遮断しないといった構成により、季節等により水温の差が大きく変化するような条件下であっても、熱交換器３０でのドレンや沸騰を防ぐことができ、しかも低コストで実現できる。また、バイパス流路を完全に遮断しない構成により低コストで器具の流路抵抗を減らすことができ、供給水圧が低い条件下であっても十分な出湯量を得ることができる。
【００３２】
尚、水温によってドレン限界を下回るか沸騰限界を上回る恐れのある設定温度の場合には、入水温センサの検出温度に応じて電磁弁５３を開閉するようにしてもよい
【００３３】
次に、本発明の第３実施例について説明する。図６は第３実施例としての給湯器の概略構成図である。基本的な構成は第１実施例（図１）と同一であるが、電磁弁５１の代りに開度調整弁９０を設けた点と、オリフィス５２を設けていない点とで異なる。その他重複する構成については、同一符号を付してその説明を省略する。
【００３４】
開度調整弁９０は、熱交換器流量とバイパス流量との比率を可変するために設けられるもので、バイパス路５０と直列に連結されるケース９１と、ケース９１の内壁面に密着された状態で摺動可能に設けられる摺動弁体９２と、一定のばね荷重で摺動弁体９２をバイパス路５０上流側に付勢するバイアスばね９３と、温度に応じてばね荷重が変化し摺動弁体９２をバイパスばね９３と抗する向きに付勢するＳＭＡばね９４とからなる。
【００３５】
ＳＭＡばね９４は、コントローラ６０からの通電量に応じてばね自身の電気抵抗によりジュール熱を発生し、その温度により荷重変化する。そして開度調整弁９０は、ＳＭＡばね９４とバイアスばね９３との弾性力がつりあった位置に摺動弁体９２を位置させることにより流路抵抗を決定する。
【００３６】
コントローラ６０は、出口温センサ２１の検出温度が６５℃より高い場合にはＳＭＡばね５４への通電量を増加させて開度調整弁９０の開度を小さくし、６５℃より低い場合にはＳＭＡばね５４への通電量を減少させて開度調整弁９０の開度を大きくするというように制御することで、図７のグラフに示すように出口温センサ２１の検出温度をほぼ６５℃に保つ。そのため、熱交換器３０の出口温度は、設定温度や水温に関係なく、沸騰限界とドレン限界とのほぼ中間位置に維持される。
【００３７】
以上説明したように、第３実施例の給湯器によれば、熱交換器３０の出口温度を沸騰限界とドレン限界とのほぼ中間位置に維持するようにバイパス率を可変するため、熱交換器３０での沸騰やドレンの発生を確実に防ぐことができる。
【００３８】
尚、本実施例では開度調整弁９０によりバイパス率を可変したが、これに限ったものではなく、例えばモータにより弁開度を調整する構成であってもよい。
また、本実施例では出口温センサ２１の検出温度を一定にするようにバイパス率を制御したが、これに限ったものではなく、熱交換器３０の出口温度をドレン限界と沸騰限界との間に制限するものであればよい。
【００３９】
以上本発明の実施例について説明したが、本発明はこうした実施例に何等限定されるものではなく、本発明の要旨を逸脱しない範囲において、種々なる態様で実施し得ることは勿論である。
【００４０】
【発明の効果】
以上詳述したように、本発明の請求項１記載の給湯器によれば、入水温度による最大出湯量の補正量を大きくすることで水温の違いに対しても出湯性能を十分に維持することができ、しかも１つの水温補正式水ガバナのみにより補正できるため低コストで実現できる。
【００４１】
更に、本発明の請求項２記載の給湯器は、電磁弁によりバイパス率を切り換える構成によりコストを低減することができる。
【００４２】
更に、本発明の請求項３記載の給湯器は、熱交換器出口の湯温度に基づき、開度調節弁の開度を調節することで熱交換器出口の湯温が上記ドレン限界温度と沸騰上限温度との間の温度に保持する。よって、沸騰やドレンの発生を防止することができる。
【図面の簡単な説明】
【図１】第１実施例としての給湯器の概略構成図である。
【図２】熱交換器の出口温度とバイパス率との関係を表わすグラフである。
【図３】第１水ガバナの概略構成図である。
【図４】第２実施例としての給湯器の概略構成図である。
【図５】熱交換器の出口温度とバイパス率との関係を表わすグラフである。
【図６】第３実施例としての給湯器の概略構成図である。
【図７】熱交換器の出口温度とバイパス率との関係を表わすグラフである。
【図８】従来例としての給湯器の概略構成図である。
【符号の説明】
１０…給水路、１２…第２水ガバナ、２０…出湯路、３０…熱交換器、
４０…バーナ、５０…バイパス路、５１…電磁弁、
６０…コントローラ、７０…リモコン、８０…第１水ガバナ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water heater, and more particularly, to a bypass mixing type water heater.
[0002]
[Prior art]
Conventionally, a water heater provided with a bypass passage that bypasses the heat exchanger is known. For example, in what is shown in FIG. 8, the heat exchanger 3 to which the water supply path 1 and the hot water path 2 are connected, the burner 4 for heating the water which flows through the heat exchanger 3, and the bypass which bypasses the heat exchanger 3 A path 5 and a controller 6 for controlling combustion are provided. A flow rate sensor 1a for detecting the incoming water flow rate is provided upstream of the branch portion of the water supply passage 1 with the bypass passage 5, and water flowing through the heat exchanger 3 is provided downstream of the branch portion with the bypass passage 5. A water temperature correction type water governor 1b for limiting the maximum flow rate is provided. Further, a hot water temperature sensor 2 a for detecting the hot water temperature after mixing is provided on the downstream side of the junction with the bypass channel 5 of the hot water channel 2. Further, the bypass passage 5 is provided with a water governor 5a for limiting the maximum flow rate of water flowing through the bypass passage 5, and a bypass valve 5b for opening and closing the passage. The controller 6 is connected to a remote controller 7 for setting a set temperature. And at the time of low temperature setting, the bypass valve 5b is opened and the water supplied from the water supply channel 1 is divided into the heat exchanger 3 side and the bypass channel 5 side, and the hot water heated by the heat exchanger 3 and the bypass channel 5 are separated. By mixing the water that has passed through and discharging the hot water, the temperature of the hot water in the heat exchanger 3 is made higher than the actual hot water temperature to suppress the generation of drain (condensation) and prevent the heat exchanger 3 from corroding. . When the high temperature is set, the bypass valve 5b is closed and all the water supplied from the water supply channel 1 is caused to flow to the heat exchanger 3 side, thereby preventing boiling of hot water in the heat exchanger 3.
[0003]
Further, the water governor 5a is provided in the bypass channel 5 to limit the maximum flow rate of the water flowing through the bypass channel 5, and the water temperature correction type water governor 1b is also provided downstream from the branch portion of the water supply channel 1 with the bypass channel 5. Thus, the maximum flow rate of water flowing through the heat exchanger 3 is limited. By limiting the maximum flow rate of water in this way, the problem that the amount of hot water cannot be raised to the set temperature due to the amount of hot water exceeding the capacity of the appliance is prevented.
[0004]
Further, by providing the water governors 1b and 5a in the flow paths after branching in this way, the maximum amount of hot water discharged when the bypass valve 5b is opened increases compared to the maximum amount of hot water discharged when the bypass valve 5b is closed. . Since the amount of hot water that can be tapped at the set temperature becomes larger as the set temperature is lower, it is easier to use because low-temperature hot water can be used in a larger amount than when the amount of tapping is simply limited to a constant value.
[0005]
The amount of hot water that can be discharged at the set temperature also changes depending on the incoming water temperature, and becomes smaller as the water temperature is lower. In the example described above, since the water temperature correction type is used to restrict the flow rate on the heat exchanger 3 side, the flow rate can be reduced when the incoming water temperature is low.
The above-described example is disclosed in Japanese Utility Model Laid-Open No. 1-148558.
[0006]
[Problems to be solved by the invention]
By the way, a water temperature correction type water governor is generally configured using a spring made of a shape memory alloy (hereinafter referred to as an SMA spring), and the flow rate of the SMA spring is changed by utilizing the property that the spring load varies with temperature. ing. Here, since the rate of change of the spring load of the SMA spring cannot be so high, there is a problem that the rate of change of the restricted flow rate is also limited. In the above-described configuration, the limit flow rate of the water flowing through the bypass passage 5 is constant even when the incoming water temperature changes, so that the limit flow rate of the hot water with the bypass valve 5b opened can be changed sufficiently. In addition, the hot spring performance could not be sufficiently maintained against the difference in water temperature. However, if the water governor on the bypass side is also a water temperature correction formula, there is a problem that the cost of the instrument becomes high because the SMA spring itself is expensive.
Moreover, in such a configuration, there is a disadvantage that the lower the incoming water temperature, the higher the bypass rate and the easier the boiling.
An object of the present invention is to solve the above-described problems and to increase the correction amount based on the incoming water temperature with a simple configuration.
[0007]
[Means for Solving the Problems]
The water heater according to claim 1 of the present invention for solving the above-mentioned problems is
A heat exchanger in which a water supply channel and a hot water supply channel are respectively connected to an upstream end and a downstream end;
A gas burner for heating the heat exchanger;
A bypass path branched from the middle of the water supply path and joined in the middle of the hot water path to bypass the heat exchanger;
Having a bypass valve provided in this bypass path,
When the set temperature is lower than the drain limit temperature of the heat exchanger, the bypass valve is controlled so that the diversion ratio from the water supply path to the bypass path becomes a high bypass rate, while the set temperature is equal to or higher than the drain limit temperature. In the water heater that controls the bypass valve so that the diversion ratio from the water supply channel to the bypass channel is a low bypass rate that is lower than the high bypass rate ,
A water governor for the heat exchanger that restricts the flow rate to the heat exchanger between the branch point to the bypass passage of the water supply passage and the junction with the bypass passage of the hot water passage is provided.
The gist is to provide a full flow water governor with an incoming water temperature correction function that changes the maximum flow rate according to the water temperature temperature upstream of the branch point of the water supply channel to the bypass channel .
[0008]
The water heater according to claim 2 of the present invention for solving the above problem is the water heater according to claim 1,
The gist is that the bypass valve is an electromagnetic valve and the bypass rate is switched by ON-OFF control of the electromagnetic valve.
[0009]
Water heater according to claim 3 of the present invention to solve the above problems is the water heater according to claim 1 Symbol placement,
The above bypass valve is an opening adjustment valve whose opening can be adjusted, and an outlet temperature detection means for detecting the hot water temperature at the outlet of the heat exchanger is provided, and each water governor does not reach the maximum flow rate at the time of a high bypass rate. , Based on the detection result by the outlet temperature detecting means, the opening of the opening adjustment valve is adjusted so that the hot water temperature at the outlet of the heat exchanger is maintained at a temperature between the drain limit temperature and the boiling upper limit temperature. The gist is to adjust .
[0010]
Water heater according to the first aspect of the present invention having the above structure, based on the set temperature, Ru bypass valve is controlled to switch the bypass ratio to bypass the heat exchanger. Then, when the shunt ratio is high high bypass ratio to the bypass passage is mainly flow restriction is performed at a total flow rate of water governor Kino with incoming water temperature correction function, diversion ratio to the bypass passage is lower than the high bypass ratio low bypass ratio sometimes Oite mainly flow restriction in the heat exchanger water governor Ru made. With such a configuration, it is possible to correct the maximum hot water quantity during high bypass ratio at the same rate as the rate of change of limited flow rate corresponding to the incoming water temperature by the incoming water temperature correcting function Kino total flow water governor, the incoming water temperature It is possible to increase the correction amount of the maximum amount of hot water discharged by.
[0011]
In the water heater according to claim 2 of the present invention having the above-described configuration, since the bypass rate is switched by ON / OFF of the electromagnetic valve, the structure can be simplified and the cost can be reduced.
[0012]
The water heater according to claim 3 of the present invention having the above-described configuration is configured such that the hot water temperature at the heat exchanger outlet is adjusted to the drain limit temperature by adjusting the opening of the opening control valve based on the hot water temperature at the heat exchanger outlet. And a temperature between the boiling upper limit temperature. Therefore , boiling and drain generation can be prevented.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the water heater of the present invention will be described below.
FIG. 1 is a schematic configuration diagram of a water heater as a first embodiment of the present invention. This water heater includes a heat exchanger 30 to which the water supply path 10 and the hot water path 20 are connected, a burner 40 for heating water flowing through the heat exchanger 30, and a bypass path 50 that bypasses the heat exchanger 30. And a controller 60 for controlling the combustion. A flow rate sensor 11 for detecting the incoming water flow rate and a first water governor 80 for limiting the maximum flow rate of water supplied to the appliance are provided upstream of the branching portion A of the water supply channel 10 with the bypass channel A, A second water governor 12 that restricts the maximum flow rate of the water flowing through the heat exchanger 30 is provided on the downstream side of the branch portion A with the bypass passage 50. Further, an outlet temperature sensor 21 for detecting the hot water temperature at the outlet of the heat exchanger is provided upstream of the junction B with the bypass channel 50 of the outlet channel 20, and downstream of the junction with the bypass channel 50. A hot water temperature sensor 22 for detecting the hot water temperature after mixing is provided. Further, the bypass passage 50 is provided with an electromagnetic valve 51 that opens and closes the passage and an orifice 52 that maintains a flow ratio of branching at the branching portion A at a predetermined ratio.
[0014]
The controller 60 includes a CPU, RAM, and ROM that form a well-known arithmetic logic circuit (not shown), an input interface that inputs signals from various sensors, an output interface that outputs drive signals to various actuators, and the like. The controller 60 is connected to a remote controller 70 having operation switches for performing an external operation such as setting of a set temperature and a display for displaying the set temperature.
[0015]
The remote controller 70 sets the set temperature in a low temperature range of 38 to 46 ° C. and a high temperature range of 48, 50, 55, and 60 ° C. The controller 60 opens the solenoid valve 51 during a hot water operation when the set temperature is set to a low temperature range, and closes the electromagnetic valve 51 during a hot water operation when the set temperature is set to a high temperature range. By controlling so that the hot water heated by the heat exchanger 30 is kept at a high temperature even when the low temperature hot water is discharged, hot water heated by the heat exchanger 30 is generated when the hot water is discharged. Avoid boiling. Here, the orifice 52 provided in the bypass passage 50 is provided with a flow resistance that causes 40% of the water supplied to the appliance to be diverted to the bypass passage 50, so that the appliance is opened when the electromagnetic valve 51 is opened. The flow rate of the supplied water (hereinafter referred to as the total flow rate) and the flow rate of the water supplied to the heat exchanger 30 (hereinafter referred to as the heat exchanger flow rate) reach the first limit flow rate and the second limit flow rate, respectively. In the absence, the ratio between the heat exchanger flow rate and the flow rate flowing through the bypass 50 (hereinafter referred to as bypass flow rate) is 6: 4.
[0016]
Here, the relationship between the outlet temperature of the heat exchanger 30 and the bypass rate will be described with reference to the graph of FIG. If the boiling limit of the outlet temperature of the heat exchanger 30 is 85 ° C. and the drain limit is 48 ° C., it is necessary to keep the outlet temperature in the range of 48 ° C. to 85 ° C. In the high temperature range where the set temperature is 48 to 60 ° C., the outlet temperature of the heat exchanger 30 can be made equal to the set temperature by closing the solenoid valve 51 and can be kept above the drain limit and below the boiling limit. On the other hand, in the low temperature range where the set temperature is 38 to 46 ° C., if the hot water is discharged without bypassing, the outlet temperature of the heat exchanger 30 falls below the drain limit. Therefore, the outlet temperature of the heat exchanger 30 is made higher than the set temperature by opening the solenoid valve 51 and bypassing 40% of water. As a result, even when the set temperature is 38 ° C. which is the lowest temperature in the low temperature region and the water temperature is as high as 20 ° C., the outlet temperature of the heat exchanger 30 can be made 48 ° C. or more which is the drain limit. Even when the set temperature is 46 ° C., which is the highest temperature in the low temperature range, and the water temperature is as low as 10 ° C., the outlet temperature of the heat exchanger 30 can be made to be 85 ° C. or less which is the boiling limit.
[0017]
In addition, the controller 60 adjusts the gas supply amount by a proportional valve (not shown) provided in the gas supply path to the burner 40 so that the hot water temperature detected by the hot water temperature sensor 22 approaches the set temperature. Control the hot water temperature by controlling. At that time, the amount of heat given to the water flowing through the heat exchanger 30 with the maximum combustion amount of the burner 40 is 500 kcal / min.
Note that when the electromagnetic valve 51 is closed, the hot water temperature control may be performed so that the temperature detected by the outlet temperature sensor 21 approaches the set temperature. Since the outlet temperature sensor 21 is provided at a position closer to the heat exchanger side than the tapping temperature sensor 22, it is possible to increase the performance of tapping temperature control by quickly feeding back the detected temperature.
[0018]
Further, the controller 60 detects the outlet temperature sensor 21 and the tapping temperature sensor 22 during the tapping operation even though the set temperature is in a low temperature range, that is, in a state where a valve opening command is output to the solenoid valve 51. If it is determined that there is almost no difference in temperature, it is determined that a failure has occurred in which the solenoid valve 51 does not open. Similarly, the difference in detected temperature between the outlet temperature sensor 21 and the tapping temperature sensor 22 during the tapping operation, even though the set temperature is in a high temperature range, that is, a state in which a valve closing command is output to the solenoid valve 51. Is determined to be large, it is determined that a failure has occurred in which the solenoid valve 51 is not closed.
[0019]
The first water governor 80 is provided to limit the total flow rate. As shown in FIG. 3, the first water governor 80 is sealed to the fixed valve body 81 connected in series with the water supply passage 10 and the inner wall surface of the fixed valve body 81. The movable valve body 83 is movably provided in close contact with the member 82, and a SMA spring 84 made of a shape memory alloy that urges the movable valve body 83 against water pressure.
[0020]
In the SMA spring 84, the spring load increases as the incoming water temperature increases, and the spring load decreases as the incoming water temperature decreases. Therefore, it is possible to change the maximum flow rate (hereinafter referred to as the first restricted flow rate) that is restricted according to the incoming water temperature. In this embodiment, the first restrictive flow rate is set to 16 l / min when the incoming water temperature is 10 ° C. and to 24 l / min when the incoming water temperature is 20 ° C. Here, in order to change the flow rate by changing the spring load, it is necessary to change the spring load by the square of the flow rate change rate, and the first limited flow rate while the incoming water temperature changes from 10 ° C to 20 ° C. Is changed by 1.5 times, an SMA spring 84 is used in which the spring load changes by 1.5 ² = 2.25 times as the temperature changes.
[0021]
The first restricted flow rate is the maximum amount of discharged hot water when the solenoid valve 51 is opened, that is, when the set temperature is set in a low temperature range of 38 to 46 ° C. In this embodiment, focusing on the fact that the use frequency of 40 ° C. hot water is high at the set temperature in the low temperature region, the first limit flow rate is set so that 40 ° C. hot water can be discharged to the maximum.
When the water temperature is 10 ° C, the first limit flow rate is limited to 16 l / min.
(40 ° C-10 ° C) x 16l / min = 480kcal / min
480 kcal / min / 500 kcal / min = 0.96
Thus, it demonstrates 96% capacity at maximum combustion.
When the water temperature is 20 ° C, the first limit flow rate is limited to 24 l / min.
(40 ° C-20 ° C) x 24l / min = 480kcal / min
480 kcal / min / 500 kcal / min = 0.96
Thus, it demonstrates 96% capacity at maximum combustion.
As described above, when the set temperature is 40 ° C., a maximum amount of hot water at 40 ° C. can be discharged in large quantities.
[0022]
The second water governor 21 is provided to restrict the heat exchanger flow rate, and is set so that the maximum flow rate (hereinafter referred to as the second restricted flow rate) is 12 l / min regardless of the incoming water temperature. The second restricted flow rate is the maximum amount of hot water discharged when the solenoid valve 51 is closed, that is, when the set temperature is set in a high temperature range of 48 to 60 ° C. In this embodiment, in order to limit the second restricted flow rate to 12 l / min, when water with the maximum flow rate is heated with the maximum combustion amount,
500kcal / min / 12l / min = 41.7deg
Even when the hot water tap is opened to the maximum, 51.7 ° C. hot water can be discharged when the water temperature is 10 ° C. and 61.7 ° C. when the water temperature is 20 ° C.
[0023]
Thus, by correcting the water temperature by the first water governor 80 that limits the total flow rate, the amount of correction of the total flow rate by the water temperature correction is made larger than when the water temperature is corrected by the water governor that limits the flow rate after branching. Can do. For example, in the water heater shown in the conventional example (FIG. 8), when the heat exchanger flow rate is limited to 12 l / min when the water temperature is 20 ° C. by the water temperature correction type water governor 1b, the water temperature correction type is set when the bypass valve 5b is opened. In order to obtain the same correction amount (8 l / min) as in the present embodiment with the water governor 1b, it is necessary to change the limit flow rate from 12 l / min to 4 l / min while the water temperature changes from 20 ° C. to 10 ° C. . Thus, in order to change the flow rate three times while the water temperature changes from 10 ° C. to 20 ° C., it is necessary to use an SMA spring whose spring load changes 3 ² = 9 times. It is difficult to realize an SMA spring that changes to.
[0024]
As described above, according to the water heater of the first embodiment, the change in the limited flow rate due to the incoming water temperature can be increased by a simple configuration in which the water temperature is corrected by the first water governor 80 that limits the total flow rate. Therefore, the hot water performance can be maintained by changing the amount of hot water to the optimum amount of the incoming water. Moreover, since only one water governor for correcting the water temperature is required, it can be realized at low cost. In addition, by limiting the amount of tapping in the low temperature range and the amount of tapping in the high temperature range with separate governors, the amount of tapping in the low temperature range where a large amount of tapping can be made can be increased compared to the high temperature range. Easy to use. And since it is a simple structure which only provides two water governors, it can implement | achieve at low cost.
[0025]
The second water governor only needs to limit the maximum flow rate of the water passing through the heat exchanger 30, and may be provided upstream of the junction B with the bypass path 50 of the tap water path 20.
[0026]
Next, a second embodiment of the present invention will be described. FIG. 4 is a schematic configuration diagram of a water heater as a second embodiment. The basic configuration is the same as that of the first embodiment (FIG. 1), but differs in that an electromagnetic valve 53 having a different function is provided instead of the electromagnetic valve 51. About the other overlapping structure, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
[0027]
The electromagnetic valve 53 has a structure that does not completely close the flow path even when the valve is closed. A flow path resistance is provided by the orifice 52 so that the bypass rate when the electromagnetic valve 53 is opened is 50%. Further, a flow path resistance is set such that the bypass rate is 15% when the valve is closed.
[0028]
Here, the reason why the electromagnetic valve 53 having such a structure is used will be described.
The first reason is to reliably prevent drainage and boiling in the heat exchanger 30. In the first embodiment, as shown in the graph of FIG. 2, in order to keep the outlet temperature of the heat exchanger 30 between the drain limit and the boiling limit, 40% water is used in a low temperature range where the set temperature is 38 to 46 ° C. The outlet temperature of the heat exchanger 30 can be raised to about 50 ° C. even under conditions where drainage is likely to occur, such as when the set temperature is 38 ° C. and the water temperature is 20 ° C., but if the incoming water temperature further rises, There is a risk of falling below the limit of 48 ° C. Even in such a case, in order to prevent the generation of drain, it is necessary to further increase the bypass rate. Therefore, as shown in FIG. 5, if the bypass rate is set to 50% when the solenoid valve 53 is opened, drainage can be prevented even when the incoming water temperature becomes high, but the set temperature is 46 ° C. When the water temperature is 10 ° C., the outlet temperature of the heat exchanger 30 rises to about 82 ° C., and when the water temperature is further lowered, there is a possibility that it exceeds the boiling limit of 85 ° C. However, if the bypass flow path is shut off, the outlet temperature of the heat exchanger 30 becomes the set temperature of 46 ° C., which is lower than the drain limit of 48 ° C.
[0029]
Therefore, even if the solenoid valve 53 is closed, the bypass flow path is not completely shut off, and the bypass rate is reduced to 15%, so that the outlet of the heat exchanger 30 can be obtained even when the set temperature is 46 ° C. The temperature can be above the drain limit. Thus, when there is a possibility of boiling when the solenoid valve 53 is opened, the outlet temperature of the heat exchanger 30 is changed even under a situation where the water temperature changes greatly by closing the solenoid valve 53 and reducing the bypass rate. Can always be kept above the drain limit and below the boiling limit. Also, even when the maximum temperature in the high temperature range is set to 60 ° C., the bypass rate is as low as 15%, so the outlet temperature of the heat exchanger 30 can be suppressed to about 70 ° C., and boiling is prevented. be able to.
[0030]
The second reason is to reduce the flow resistance of the instrument. In order to obtain a sufficient amount of hot water under low supply water pressure conditions, it is necessary to reduce the flow path resistance of the appliance. Here, when trying to reduce the flow resistance on the heat exchanger 30 side, it is necessary to increase the diameter of the pipe forming the water flow path, but the pipe on the heat exchanger side is intended to increase the thermal efficiency. For this reason, it has a long and winding shape, and if this pipe diameter is changed, the cost will increase significantly. In this embodiment, since the flow rate flowing through the bypass 50 is increased as a whole, the flow resistance of the instrument can be reduced at a low cost.
[0031]
As described above, according to the water heater of the second embodiment, the difference in the water temperature varies greatly depending on the season, etc., because the bypass flow path is not completely shut off even when the solenoid valve 53 is closed. Even under such conditions, drainage and boiling in the heat exchanger 30 can be prevented, and it can be realized at low cost. In addition, the flow path resistance of the instrument can be reduced at a low cost by a configuration that does not completely block the bypass flow path, and a sufficient amount of hot water can be obtained even under conditions where the supply water pressure is low.
[0032]
In the case of a set temperature that may fall below the drain limit or exceed the boiling limit depending on the water temperature, the solenoid valve 53 may be opened and closed according to the temperature detected by the incoming water temperature sensor.
Next, a third embodiment of the present invention will be described. FIG. 6 is a schematic configuration diagram of a water heater as a third embodiment. The basic configuration is the same as that of the first embodiment (FIG. 1), but differs in that an opening degree adjusting valve 90 is provided instead of the solenoid valve 51 and an orifice 52 is not provided. About the other overlapping structure, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
[0034]
The opening adjustment valve 90 is provided to vary the ratio between the heat exchanger flow rate and the bypass flow rate, and is in close contact with the case 91 connected in series with the bypass passage 50 and the inner wall surface of the case 91. Slidable valve body 92 that is slidable at the same time, bias spring 93 that urges the sliding valve body 92 to the upstream side of the bypass passage 50 with a constant spring load, and the spring load changes according to temperature and slides It consists of an SMA spring 94 that urges the valve body 92 in a direction against the bypass spring 93.
[0035]
The SMA spring 94 generates Joule heat by the electrical resistance of the spring itself according to the amount of current supplied from the controller 60, and the load changes depending on the temperature. The opening degree adjusting valve 90 determines the flow path resistance by positioning the sliding valve body 92 at a position where the elastic force between the SMA spring 94 and the bias spring 93 is balanced.
[0036]
When the temperature detected by the outlet temperature sensor 21 is higher than 65 ° C., the controller 60 increases the energization amount to the SMA spring 54 to reduce the opening of the opening adjustment valve 90, and when it is lower than 65 ° C. By controlling the energization amount of the spring 54 to decrease and increase the opening degree of the opening adjustment valve 90, the temperature detected by the outlet temperature sensor 21 is maintained at approximately 65 ° C. as shown in the graph of FIG. . Therefore, the outlet temperature of the heat exchanger 30 is maintained at a substantially intermediate position between the boiling limit and the drain limit regardless of the set temperature and the water temperature.
[0037]
As described above, according to the water heater of the third embodiment, the bypass rate is varied so as to maintain the outlet temperature of the heat exchanger 30 at a substantially intermediate position between the boiling limit and the drain limit. Boiling at 30 and generation of drain can be reliably prevented.
[0038]
In the present embodiment, the bypass rate is varied by the opening adjustment valve 90. However, the present invention is not limited to this. For example, the valve opening may be adjusted by a motor.
In this embodiment, the bypass rate is controlled so that the temperature detected by the outlet temperature sensor 21 is constant. However, the present invention is not limited to this, and the outlet temperature of the heat exchanger 30 is set between the drain limit and the boiling limit. What is necessary is just to restrict.
[0039]
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it is needless to say that the present invention can be implemented in various modes without departing from the gist of the present invention.
[0040]
【The invention's effect】
As described above in detail, according to the hot water supply device of the first aspect of the present invention, it is possible to sufficiently maintain the tapping performance even with respect to the difference in water temperature by increasing the correction amount of the maximum tapping amount according to the incoming water temperature. Moreover, since it can be corrected by only one water temperature correction type water governor, it can be realized at low cost.
[0041]
Furthermore, the water heater according to claim 2 of the present invention can reduce the cost by the configuration in which the bypass rate is switched by the electromagnetic valve.
[0042]
Furthermore, in the water heater according to claim 3 of the present invention, the hot water temperature at the outlet of the heat exchanger is boiled with the drain limit temperature by adjusting the opening of the opening control valve based on the hot water temperature at the outlet of the heat exchanger. Hold at a temperature between the upper temperature limits. Therefore , boiling and drain generation can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a water heater as a first embodiment.
FIG. 2 is a graph showing the relationship between the outlet temperature of the heat exchanger and the bypass rate.
FIG. 3 is a schematic configuration diagram of a first water governor.
FIG. 4 is a schematic configuration diagram of a water heater as a second embodiment.
FIG. 5 is a graph showing the relationship between the outlet temperature of the heat exchanger and the bypass rate.
FIG. 6 is a schematic configuration diagram of a water heater as a third embodiment.
FIG. 7 is a graph showing the relationship between the outlet temperature of the heat exchanger and the bypass rate.
FIG. 8 is a schematic configuration diagram of a water heater as a conventional example.
[Explanation of symbols]
10 ... Water supply channel, 12 ... Second water governor, 20 ... Hot water supply channel, 30 ... Heat exchanger,
40 ... Burner, 50 ... Bypass, 51 ... Solenoid valve,
60 ... Controller, 70 ... Remote control, 80 ... First water governor.

Claims

A heat exchanger in which a water supply channel and a hot water supply channel are respectively connected to an upstream end and a downstream end;
A gas burner for heating the heat exchanger;
A bypass path branched from the middle of the water supply path and joined in the middle of the hot water path to bypass the heat exchanger;
Having a bypass valve provided in this bypass path,
When the set temperature is lower than the drain limit temperature of the heat exchanger, the bypass valve is controlled so that the diversion ratio from the water supply path to the bypass path becomes a high bypass rate, while the set temperature is equal to or higher than the drain limit temperature. In the water heater that controls the bypass valve so that the diversion ratio from the water supply channel to the bypass channel is a low bypass rate that is lower than the high bypass rate ,
A water governor for the heat exchanger that restricts the flow rate to the heat exchanger between the branch point to the bypass passage of the water supply passage and the junction with the bypass passage of the hot water passage is provided.
A water heater having a full flow rate water governor with an incoming water temperature correction function for changing a maximum flow rate according to a water temperature temperature upstream from a branch point to the bypass channel of the water supply channel .

The bypass valve is an electromagnetic valve, water heater 請 Motomeko 1 wherein for switching the bypass ratio by ON-OFF control of the solenoid valve.

The bypass valve is an opening degree adjustment valve whose opening degree can be adjusted, and provided with outlet temperature detection means for detecting the hot water temperature at the heat exchanger outlet, and each water governor does not reach the maximum flow rate at the time of a high bypass rate. , Based on the detection result by the outlet temperature detecting means, the opening of the opening adjustment valve is adjusted so that the hot water temperature at the outlet of the heat exchanger is maintained at a temperature between the drain limit temperature and the boiling upper limit temperature. water heater according to claim 1 Symbol placement adjusting.