JP3898407B2

JP3898407B2 - Condensation prevention control device for hot water circulating boiler

Info

Publication number: JP3898407B2
Application number: JP2000014349A
Authority: JP
Inventors: 茂雄近藤; 和博中澤; 史生渡部; 誠新部
Original assignee: Corona Corp
Current assignee: Corona Corp
Priority date: 2000-01-24
Filing date: 2000-01-24
Publication date: 2007-03-28
Anticipated expiration: 2020-01-24
Also published as: JP2001201063A

Description

【０００１】
【発明の属する技術分野】
本発明は温水循環式ボイラに関し、熱交換器の結露発生の防止を図ったものである。
【０００２】
【従来の技術】
従来よりこの種の温水循環式ボイラに於いては、燃焼装置と熱交換器を持つボイラと放熱器による温水の循環回路を備えたものであるが、放熱器の負荷が大きくなると熱交換器へ戻ってくる温水の温度が２０℃程度まで低下してしまうことがあり、この場合熱交換器で燃焼ガスを急冷してしまい熱交換面に結露が発生してしまう欠点があった。特に燃焼量が小さい場合には結露の発生が頻繁に起こり易く、熱交換器に結露が発生した状態で長時間運転を継続すると燃焼装置や熱交換器の破損や腐触を引き起こすものであった。
【０００３】
これを解決するため従来の温水循環式ボイラに於いては、例えば特開平５−１９５５０８号公報に開示されているように、燃焼装置と熱交換器を持つボイラと融雪用放熱器による温水の密閉循環回路を備えたものに於いて、温水の往き管と戻り管の間にバイパス管を設け、往き管に融雪用放熱器側から熱交換器に戻ってくる温水温度が低いときに閉止側へ動作する流量調節弁装置を設け、この流量調節弁装置の閉止動作によりバイパス管から戻り管へ高温の往き管の温水を流入させるようにして熱交換器の結露を防止するものであった。
【０００４】
【発明が解決しようとする課題】
ところでこの従来のものでは、循環回路中に必ずバイパス管及び流量調節弁装置を設けなければならず、多くの部品を必要としコスト高になり設備が大型化すると共に、放熱器に流れるはずの高温水の全部または一部をバイパスさせてしまうため、放熱器での放熱量が大幅に減少してしてしまうものであって、融雪または暖房の効率が非常に悪いものであった。
【０００５】
【問題点を解決するための手段】
本発明はこの点に着目し、上記欠点を解決する為、請求項１では特にその構成を、燃焼装置と熱交換器とを備え前記熱交換器と放熱器とを循環回路にて温水を循環可能に接続した温水循環式ボイラに於いて、前記放熱器の下流側に放熱器で放熱した温水の温度を検知する戻り温度センサを備え、該戻り温度センサが前記熱交換器に結露が発生する第１の所定温度以下を所定時間継続して検知した場合に前記燃焼装置の燃焼量を一段階増加し、戻り温度センサが検知する温度が前記第１の所定温度より高い第２の所定温度以上を所定時間継続して検知するまで、所定時間経過する毎に燃焼装置の燃焼量を一段階増加するものである。
【０００６】
また、請求項２では特にその構成を、前記請求項１のものに於いて、戻り温度センサが検知する温度が前記第１の所定温度より高い第２の所定温度以上を所定時間継続して検知した時、戻り温度センサが検知する温度が第２の所定温度以下を所定時間継続して検知するまで、所定時間経過する毎に燃焼装置の燃焼量を一段階減少させるものである。
【０００７】
また、請求項３では特にその構成を、燃焼装置と熱交換器とを備え前記熱交換器と放熱器とを循環回路にて温水を循環可能に接続し、前記熱交換器下流での往き温水の目標温度を設定する往き温水温度設定手段と、前記熱交換器の下流側に前記熱交換器から流出する往き温水の温度を検知する往き温度センサとを備え、前記往き温度センサで検知する温水温度が往き温水温度設定手段で設定された目標温度になるよう燃焼量を可変するようにした温水循環式ボイラに於いて、前記放熱器の下流側に放熱器で放熱した温水の温度を検知する戻り温度センサを備え、該戻り温度センサが前記熱交換器に結露が発生する第１の所定温度以下を所定時間継続して検知した場合に前記往き温水温度設定手段で設定された目標温度を所定温度増加させると共に、温水を循環させる循環ポンプの回転数を増加し、戻り温度センサが検知する温度が前記第１の所定温度より高い第２の所定温度以上を所定時間継続して検知するまで、所定時間経過する毎に往き温水温度の目標温度を所定温度増加させると共に、循環ポンプの回転数を増加するものである。
【０００８】
また、請求項４では特にその構成を、前記請求項３のものに於いて、戻り温度センサが検知する温度が前記第１の所定温度より高い第２の所定温度以上を所定時間継続して検知した時、戻り温度センサが検知する温度が第２の所定温度以下を所定時間継続して検知するまで、所定時間経過する毎に往き温水温度の目標温度を所定温度減少させると共に、循環ポンプの回転数を元に戻すものである。
【０００９】
【発明の実施の形態】
前記請求項１に係る発明によると、燃焼装置１４と熱交換器１３とを備え前記熱交換器１３と放熱器１４とを循環回路７にて温水を循環可能に接続した温水循環式ボイラ１に於いて、前記放熱器４の下流側に放熱器４で放熱した温水の温度を検知する戻り温度センサ２０を備え、該戻り温度センサ２０の検知する戻り温水温度が前記熱交換器１３に結露が発生する第１の所定温度（例えば３０℃）以下を所定時間継続すると、結露防止のために前記燃焼装置１４の燃焼量を一段階増加し、戻り温度センサが検知する温度が前記第１の所定温度より高い第２の所定温度以上を所定時間継続して検知するまで、所定時間経過する毎に燃焼装置の燃焼量を一段階増加することを繰り返して燃焼量を増加し、循環温水に与える熱量を増やすことによって戻り温水温度を結露が発生しない温度まで昇温させると共に、結露の発生しにくい高燃焼量側へ燃焼量を増加するので更に結露が発生しにくくなるものである。
【００１０】
また、前記請求項２に係る発明によると、燃焼量の増加に伴い戻り温度センサ１９の検知する戻り温水温度が前記第１の所定温度より高い第２の所定温度（ここでは４０℃）以上の４２℃まで上昇し所定時間以上経過したとすると、燃焼量を一段階減少させて上がりすぎた戻り温水温度を低下させるようにする。そして戻り温水温度が第２の所定温度（ここでは４０℃）以下を所定時間継続するまで所定時間毎に燃焼量を一段階減少させることを繰り返すので、戻り温水温度が前記熱交換器１２に結露を起こさせない温度になるよう制御して、結露が発生しにくい状態にあるのに高燃焼量で燃焼を継続してしまって無駄にエネルギーを消費してしまうことがなく、不要な温度上昇を防いで運転の適正化を図り無駄にする熱量を抑制し省エネルギーにも貢献するものである。
【００１１】
また、前記請求項３にかかる発明によると、燃焼装置１４と熱交換器１３とを備え前記熱交換器１３と放熱器４とを循環回路７にて温水を循環可能に接続し、前記熱交換器１３下流での往き温水の目標温度を設定する往き温水温度設定手段２９と、前記熱交換器１３の下流側に前記熱交換器１３から流出する温水の温度を検知する往き温度センサ１９とを備え、前記往き温度センサ１９で検知する温水温度が往き温水温度設定手段２９で設定された目標温度になるよう燃焼量を可変するようにした温水循環式ボイラ１に於いて、前記放熱器４の下流側に放熱器４で放熱した温水の温度を検知する戻り温度センサ２０を備え、該戻り温度センサ２０が前記熱交換器１３に結露が発生する第１の所定温度（例えば３０℃）以下を所定時間継続して検知した場合に、前記往き温水温度設定手段２９で設定された目標温度を数度（例えば５℃）だけ上げると共に、温水を循環させる循環ポンプの回転数を増加し、戻り温度センサが検知する温度が前記第１の所定温度より高い第２の所定温度以上を所定時間継続して検知するまで、所定時間経過する毎に往き温水温度の目標温度を所定温度上げることを繰り返すので、往き温度センサ１９の検知する温水温度が前記往き温水温度設定手段２９で設定された目標温度より低くなって燃焼装置１４は燃焼量を増加し、従って循環温水に与える熱量を増やすことによって戻り温水温度を結露が発生しない温度まで昇温させるものである。
このように、往き温水の目標温度を数度ずつ上げることで燃焼量を増加させて循環温水に与える熱量を増加すると共に、循環温水の循環速度を速めて放熱器４での放熱量を減らすことによって効率よく戻り温水温度を結露が発生しない温度まで昇温させ、結露の発生しにくい高燃焼量側へ燃焼量を増加するので更に結露が発生しにくくなり、また、往き温水の目標温度を戻り温水温度の状況を検知しながら数度ずつ段階的に上げていくので、結露防止のために最低限必要な熱量を適切に与えることができて省エネルギーであると共に、放熱器４により加熱される負荷に対して過剰に熱してしまうことを防止できるものである。
【００１２】
また、前記請求項４にかかる発明によると、前記請求項３のものに於いて、戻り温度センサが検知する温度が前記第１の所定温度より高い第２の所定温度以上を所定時間継続して検知した時、往き温水の目標温度を数度だけ下げ、同時に循環ポンプ１６の回転数を元の回転数に戻して、上がりすぎた戻り温水温度を低下させるようにする。そして戻り温水温度が第２の所定温度（ここでは４０℃）以下を所定時間継続するまで所定時間経過する毎に往き温水温度の目標温度を所定温度減少させると共に、循環ポンプの回転数を元に戻すことを繰り返すことで、戻り温水温度が前記熱交換器１２に結露を起こさせない温度になるよう制御して、結露が発生しにくい状態にあるのに高燃焼量で燃焼を継続してしまって無駄にエネルギーを消費してしまうことがなく、不要な温度上昇を防いで運転の適正化を図り無駄にする熱量を抑制し省エネルギーにも貢献するものである。
【００１３】
【実施例】
本発明の第１の実施例を図面に基づいて説明する。
図１に於いて、１は温水循環式のボイラであり、該ボイラ１で加熱された温水が往き管２及び往きヘッダー３を通過して地面に埋設された複数の融雪用の放熱器４に分流され、それぞれの融雪用の放熱器４を流通して歩道等に積もった雪を融かした後に、戻りヘッダー５で合流され、戻り管６を通過して再び前記ボイラ１へ循環流通する循環回路７を備えている。
【００１４】
８は前記ボイラ１の運転の発停を指示するリモートコントロール装置であり、運転スイッチ（図示せず）を有していると共に、降雪センサ制御部９と接続されている。この降雪センサ制御部９には、水検知センサ及び外気温センサ（共に図示せず）より構成され降雪の有無を検知する降雪センサ１０と、前記融雪用の放熱器４付近に埋設され地中温度を検出する地温センサ１１とが接続されており、該降雪センサ制御部９は雪が降り始めると前記ボイラ１の運転を開始するよう、また、その後地中温度が一定温度以上まで昇温され且つ降雪が止むと前記ボイラ１の運転を停止するように前記リモートコントロール装置８を介して前記ボイラ１へ指示するものである。
【００１５】
次に、前記ボイラ１について説明する。
図２に於いて、１２は前記戻り管６と接続され、融雪用の放熱器４で融雪に供されて温度の低下した温水が戻ってくる循環戻り口であり、１３は下部に燃焼装置１４を備え前記循環戻り口１２から戻ってきた温水を加熱する貫流式の熱交換器であり、１５は前記熱交換器１３から出湯する温水温度の均一化を図るミキシングタンクであり、１６は前記ミキシングタンク１５の下流側の循環回路７中に位置し温水を循環させる循環ポンプであり、１７は前記往き管２と接続され、前記熱交換器１３で加熱された温水を融雪用の放熱器４へ流す循環往き口であり、１８は加熱された温水の膨張を吸収する膨張タンクであり、１９は前記熱交換器１３の下流側に設けられて熱交換器１３から出て行く温水の温度を検知する往き温度センサであり、２０は前記放熱器４の下流側に設けられて前記熱交換器１３に流入する温水の温度を検知する戻り温度センサである。
【００１６】
前記燃焼装置１４は、気化ヒータ２１で加熱された気化器２２に灯油を燃料ポンプ２３で噴霧して気化し、この気化ガスと燃焼用送風機２４からの燃焼用空気とを混合してバーナヘッド２５で燃焼させ、燃焼ガスを前記貫流式の熱交換器１３を通過させて温水を加熱し、前記熱交換器１３上部に設けられた排気トップ２６から排気するもので、この燃焼装置１４は前記燃料ポンプ２３及び燃焼用送風機２４をそれぞれ能力制御して燃焼量を可変できるものである。
尚、ここでは燃料に灯油を用いた燃焼装置１４としたが、これに限らずガス燃料を用いる燃焼量可変のガスバーナでもよいもので、また、前記熱交換器１３は貫流式のものとしたが、これに限らずフィンチューブ式の熱交換器でもよいものである。
【００１７】
２７はマイクロコンピュータ２８を主体としてこのボイラ１の制御を行う制御装置で、前記リモートコントロール装置８と往き温度センサ１９と戻り温度センサ２０からの入力を受け、前記気化ヒータ２１と燃料ポンプ２３と燃焼用送風機２４と循環ポンプ１６を駆動制御するもので、この制御装置２７の機能の一つとして後述する結露防止制御を行うものである。
【００１８】
次に、この第１の実施例の結露防止制御装置の作動を図４のフローチャートに基づいて説明する。
まず、ステップ１（以下Ｓ１と略す）で前記戻り温度センサ２０の検知する融雪用の放熱器４を流通して温度低下した温水の温度が、前記熱交換器１３に結露が発生する可能性の高い第１の所定温度（ここでは３０℃）以下で所定時間継続したかをチェックする。今、例えば戻り温水温度が２６℃を所定時間継続したとすると前記Ｓ１で「Yes」で次のＳ２に進み、現在の燃焼量が最大燃焼量であるかどうかをチェックする。最大燃焼量でない場合は、前記Ｓ２で「No」であるので、次のＳ３へ進み燃焼量を一段階増加する。
【００１９】
前記Ｓ３で燃焼量を増加したので循環温水に与えられる熱量が多くなり、従って融雪用の放熱器４から戻ってくる温水の温度も上昇する。
ここで例えば戻り温水温度が３℃上昇して２９℃になったとすると、Ｓ４で温水の戻り温度が前記第１の所定温度より高い第２の所定温度（ここでは４０℃）以上を所定時間継続したかをチェックし、ここでは戻り温水温度は２９℃であるので、前記Ｓ４で「No」となり、前記Ｓ１へ戻る。このＳ１では、戻り温水温度は２９℃で所定時間継続したとすると、再びＳ２〜Ｓ４のステップを繰り返し燃焼量を増加し、循環温水に与える熱量を増やすことによって戻り温水温度を結露が発生しない温度まで昇温させると共に、結露の発生しにくい高燃焼量側へ燃焼量を増加するので更に結露が発生しにくくなるものである。
【００２０】
このとき燃焼量の増加に伴い前記戻り温度センサ１９の検知する戻り温水温度が４２℃まで上昇し所定時間以上経過したとすると、前記Ｓ４で「Yes」となり、次のＳ５へ進み、燃焼量を一段階減少させて上がりすぎた戻り温水温度を低下させるようにする。そして戻り温水温度が第２の所定温度（ここでは４０℃）以下を所定時間継続するまでＳ４及びＳ５を繰り返し、再びＳ１のステップに戻ることで、戻り温水温度が前記熱交換器１２に結露を起こさせない温度になるよう制御して、結露が発生しにくい状態にあるのに高燃焼量で燃焼を継続してしまって無駄にエネルギーを消費してしまうことがなく、不要な温度上昇を防いで運転の適正化を図り無駄にする熱量を抑制し省エネルギーにも貢献するものである。
【００２１】
ここで、結露防止のため燃焼量を最大にまで増加しても、戻り温水温度が前記熱交換器１３に結露が発生する可能性の高い第１の所定温度（ここでは３０℃）以下を所定時間継続してしまう場合、前記Ｓ２で「Yes」となり、Ｓ６の燃焼停止のステップへ進み、燃料ポンプ２３及び燃焼用送風機２４を駆動停止して燃焼を停止するので、結露が発生している状態で長時間運転を継続することがなく燃焼装置１４及び熱交換器１３の破損や腐触を未然に防ぐことができ、また、結露以外の何等かの異常に対しても安全である。
【００２２】
よって、従来のように往き管の高温水を戻り管の低温水に混合させるためのバイパス管及び弁装置を必要とせずコスト安であり、簡単な制御によって熱交換器１３の結露を確実に防止することができて結露水による燃焼装置１４や熱交換器１３の破損や腐触を起こすことがないと共に、放熱器４には全温水が流通するので、放熱器４での放熱量が大幅に減少するようなこともなく、融雪や暖房の効率を低下させることがないという優れた効果を有するものである。
【００２３】
次に、本発明の第２の実施例について説明する。尚、前記第１の実施例と同一のものには同一の符号を付して説明を省略する。
この第２の実施例では、前記循環ポンプ１６は回転数可変型のもの（例えば駆動モータに対し位相制御や巻線数切換等を行うことにより回転数可変可能）が用いられているほか、前記リモートコントロール装置８は、往き温水温度設定手段２９を備えており、前記熱交換器１３から流出する往き温水の目標温度を数度刻み（例えば５℃刻み）で手動または使用条件に応じて自動で設定可能としている。
【００２４】
前記制御装置２７は、往き温水温度が前記往き温水温度設定手段２９で設定された目標温度になるように、前記往き温度センサ１９の検知する温水温度に基づき前記燃料ポンプ２３及び燃焼用送風機２４を制御して燃焼量を増減する。すなわち、往き温度センサ１９の検知する温水温度が前記往き温水温度設定手段２９で設定された目標温度より低ければ燃焼量を増加し、また、高ければ燃焼量を減少するものである。
【００２５】
次に、この第２の実施例の結露防止制御装置の作動を図６のフローチャートに基づいて説明する。
まず、ステップ７で前記戻り温度センサ２０の検知する融雪用の放熱器４を流通して温度低下した温水の温度が、前記熱交換器１３に結露が発生する可能性の高い第１の所定温度（ここでは３０℃）以下を所定時間継続したかをチェックする。今、例えば戻り温水温度が２６℃を所定時間継続したとすると前記Ｓ７で「Yes」で次のＳ８に進み、現在の往き温水の目標温度が最高設定温度であるかどうかをチェックする。最高設定温度でない場合は、前記Ｓ８で「No」であるので、次のＳ９へ進み往き温水温度設定手段２９が往き温水の目標温度を数度だけ上げる。例えば、往き温水の目標温度が６０℃であったのを５℃上げて６５℃にする。更に、次のＳ１０で前記循環ポンプ１６の回転数を上げて、温水の循環速度を上げる。
【００２６】
前記Ｓ９で往き温水の目標温度を数度だけ上げたので、前記制御装置２７は前記往き温度センサ１９の検知する温水温度を目標温度（ここでは例えば６５℃）になるよう燃焼量を増加して循環温水に与える熱量を多くし、従って融雪用の放熱器４から戻ってくる温水の温度も上昇する。
【００２７】
また、前記Ｓ１０で前記循環ポンプ１６の回転数を上げたので、前記融雪用の放熱器４内を流通する時間が短くなって放熱器４内で循環温水から放熱する熱量が少なくなり、従って融雪用の放熱器４から戻ってくる温水の温度も上昇する。
【００２８】
今、例えば戻り温水温度が３℃上昇して２９℃になったとする。そして、次のＳ１１では温水の戻り温度が前記第１の所定温度より高い第２の所定温度（ここでは４０℃）以上を所定時間継続したかをチェックする。ここでは戻り温水温度は２９℃であるので、前記Ｓ１１で「No」となり、前記Ｓ７へ戻る。このＳ７では、戻り温水温度は２９℃で所定時間継続すると、再びＳ８〜Ｓ１１を繰り返し往き温水の目標温度を数度ずつ上げる。
【００２９】
このように、往き温水の目標温度を数度ずつ上げることで燃焼量を増加させて循環温水に与える熱量を増やすると共に、循環温水の循環速度を速めて放熱器４での放熱量を減らすことによって効率よく戻り温水温度を結露が発生しない温度まで昇温させ、結露の発生しにくい高燃焼量側へ燃焼量を増加するので更に結露が発生しにくくなるものである。
【００３０】
また、往き温水の目標温度を戻り温水温度の状況を検知しながら数度ずつ段階的に上げていくので、結露防止のために最低限必要な熱量を適切に与えることができて省エネルギーであると共に、放熱器４により加熱される負荷に対して過剰に熱してしまうことを防止できるものである。（融雪ではなく、暖房用に本発明を用いた場合には、過剰暖房を防止できるという優れた効果を奏するものである。）
【００３１】
そして往き温水の目標温度を高く設定したことに伴い前記戻り温度センサ１９の検知する戻り温水温度が４２℃まで上昇し所定時間以上経過したとすると、前記Ｓ１１で「Yes」となり、次のＳ１２へ進み、往き温水の目標温度を数度だけ下げ、同時にＳ１３で循環ポンプ１６の回転数を元の回転数に戻して、上がりすぎた戻り温水温度を低下させるようにする。そして戻り温水温度が第２の所定温度（ここでは４０℃）以下を所定時間継続するまでＳ１１〜Ｓ１３を繰り返し、再びＳ７のステップに戻ることで、戻り温水温度が前記熱交換器１２に結露を起こさせない温度になるよう制御して、結露が発生しにくい状態にあるのに高燃焼量で燃焼を継続してしまって無駄にエネルギーを消費してしまうことがなく、不要な温度上昇を防いで運転の適正化を図り無駄にする熱量を抑制し省エネルギーにも貢献するものである。
【００３２】
ここで、結露防止のため往き温水の目標温度を最高設定温度（ここでは８０℃が最高設定温度）に設定しても、戻り温水温度が前記熱交換器１３に結露が発生する可能性の高い第１の所定温度（ここでは３０℃）以下を所定時間継続してしまう場合、前記Ｓ８で「Yes」となり、Ｓ１４の燃焼停止のステップへ進み、燃料ポンプ２３及び燃焼用送風機２４を駆動停止して燃焼を停止するので、結露が発生している状態で長時間運転を継続することがなく燃焼装置１４及び熱交換器１３の破損や腐触を未然に防ぐことができ、また、結露以外の何等かの異常に対しても安全である。
【００３３】
よって、従来のように往き管の高温水を戻り管の低温水に混合させるためのバイパス管及び弁装置を必要とせずコスト安であり、簡単な制御によって熱交換器１３の結露を確実に防止することができて結露水による燃焼装置１４や熱交換器１３の破損や腐触を起こすことがないと共に、放熱器１４には全温水が流通するので、放熱器４での放熱量が大幅に減少するようなこともなく、融雪や暖房の効率を低下させることがないという優れた効果を有するものである。
【００３４】
尚、第１、第２の実施例共に融雪用の温水循環式ボイラとして説明したが、本発明はこれに限らず暖房用に用いることもでき、例えば放熱器４として家屋床材内に蛇行して配設した温水パイプを用いた床暖房システムや、また、放熱器４として室内に設置したファンコンベクタやパネルラジエータ等により暖房を行う温風暖房装置にも本発明は有用なものである。
【００３５】
【発明の効果】
以上のように請求項１の発明によれば、戻り温度センサが検知する温度が前記第１の所定温度より高い第２の所定温度以上を所定時間継続して検知するまで、所定時間経過する毎に燃焼装置の燃焼量を一段階増加することを繰り返して燃焼量を増加することで、循環温水に与える熱量を増やすことによって戻り温水温度を結露が発生しない温度まで昇温させると共に、結露の発生しにくい高燃焼量側へ燃焼量を増加するので更に結露が発生しにくくなるものである。
また、従来のように往き管の高温水を戻り管の低温水に混合させるためのバイパス管及び弁装置を必要とせずコスト安であり、簡単な制御によって熱交換器の結露を確実に防止することができて結露水による燃焼装置や熱交換器の破損や腐触を起こすことがないと共に、放熱器には全温水が流通するので、放熱器での放熱量が大幅に減少するようなこともなく、融雪や暖房の効率を低下させることがないという優れた効果を有するものである。
また、請求項２の発明によれば、戻り温水温度が第２の所定温度以下を所定時間継続するまで所定時間毎に燃焼量を一段階減少させることを繰り返すので、戻り温水温度が前記熱交換器に結露を起こさせない温度になるよう制御して、結露が発生しにくい状態にあるのに高燃焼量で燃焼を継続してしまって無駄にエネルギーを消費してしまうことがなく、不要な温度上昇を防いで運転の適正化を図り無駄にする熱量を抑制し省エネルギーにも貢献するものである。
また、請求項３の発明によれば、往き温水の目標温度を数度ずつ上げることを繰り返すことで燃焼量を増加させて循環温水に与える熱量を増加すると共に、循環温水の循環速度を速めて放熱器での放熱量を減らすことによって効率よく戻り温水温度を結露が発生しない温度まで昇温させ、結露の発生しにくい高燃焼量側へ燃焼量を増加するので更に結露が発生しにくくなり、また、往き温水の目標温度を戻り温水温度の状況を検知しながら数度ずつ段階的に上げていくので、結露防止のために最低限必要な熱量を適切に与えることができて省エネルギーであると共に、放熱器により加熱される負荷に対して過剰に熱してしまうことを防止できるものである。
また、請求項４の発明によれば、戻り温水温度が第２の所定温度以下を所定時間継続するまで所定時間経過する毎に往き温水温度の目標温度を所定温度減少させると共に、循環ポンプの回転数を元に戻すことを繰り返すことで、戻り温水温度が前記熱交換器に結露を起こさせない温度になるよう制御して、結露が発生しにくい状態にあるのに高燃焼量で燃焼を継続してしまって無駄にエネルギーを消費してしまうことがなく、不要な温度上昇を防いで運転の適正化を図り無駄にする熱量を抑制し省エネルギーにも貢献するものである。
【図面の簡単な説明】
【図１】この発明の第１の実施例の概略構成図。
【図２】同第１の実施例のボイラの概略構成図。
【図３】同第１の実施例の制御装置のブロック図。
【図４】同第１の実施例の作動を示すフローチャート。
【図５】同第２の実施例の制御装置のブロック図。
【図６】同第２の実施例の作動を示すフローチャート。
【符号の説明】
１ボイラ
４放熱器
７循環回路
１３熱交換器
１４燃焼装置
１９往き温度センサ
２０戻り温度センサ
２９往き温水温度設定手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hot water circulation boiler and is intended to prevent the occurrence of condensation in a heat exchanger.
[0002]
[Prior art]
Conventionally, this type of hot water circulation boiler is equipped with a boiler with a combustion device and a heat exchanger, and a hot water circulation circuit with a radiator, but when the load on the radiator increases, it goes to the heat exchanger The temperature of the returning warm water may be reduced to about 20 ° C., and in this case, there is a drawback that the combustion gas is rapidly cooled by the heat exchanger and condensation occurs on the heat exchange surface. In particular, when the amount of combustion is small, condensation is likely to occur frequently, and if the operation is continued for a long time with condensation on the heat exchanger, it will cause damage and corrosion of the combustion device and heat exchanger. .
[0003]
In order to solve this problem, in a conventional hot water circulation boiler, for example, as disclosed in JP-A-5-195508, a boiler having a combustion device and a heat exchanger, and sealing of warm water by a heat sink for melting snow are used. In a circuit equipped with a circulation circuit, a bypass pipe is provided between the warm water going-out pipe and the return pipe, and when the temperature of the hot water returning to the heat exchanger from the snow-melting heat sink side is low, it goes to the closing side. An operating flow rate control valve device is provided, and the flow rate control valve device is closed so that hot water in the high-temperature forward pipe flows from the bypass pipe to the return pipe to prevent condensation of the heat exchanger.
[0004]
[Problems to be solved by the invention]
By the way, with this conventional one, a bypass pipe and a flow control valve device must be provided in the circulation circuit, which requires many parts, increases costs, increases the size of the equipment, and increases the temperature that should flow to the radiator. Since all or part of the water is bypassed, the amount of heat dissipated in the radiator is greatly reduced, and the efficiency of snow melting or heating is very poor.
[0005]
[Means for solving problems]
  The present invention pays attention to this point, and in order to solve the above-described drawbacks, the present invention particularly has a structure as claimed in claim 1, comprising a combustion device and a heat exchanger, and circulating hot water in the circulation circuit between the heat exchanger and the radiator. In the hot water circulation boiler that can be connected, a return temperature sensor that detects the temperature of the hot water radiated by the radiator is provided on the downstream side of the radiator, and the return temperature sensor causes condensation on the heat exchanger.FirstWhen the temperature below the specified temperature is detected for a specified timeBeforeThe combustion amount of the combustion deviceThe combustion amount of the combustion device is increased by one every time the predetermined time elapses until the temperature detected by the return temperature sensor is continuously detected for a predetermined time at the second predetermined temperature higher than the first predetermined temperature. It is a step increase.
[0006]
  Further, in claim 2, the configuration is particularly the same as that of claim 1,When the temperature detected by the return temperature sensor is continuously detected for a predetermined time above the second predetermined temperature higher than the first predetermined temperature, the temperature detected by the return temperature sensor is continuously below the second predetermined temperature for a predetermined time. The amount of combustion of the combustion device is reduced by one step each time a predetermined time elapses until it is detected.
[0007]
  Further, in claim 3, in particular, the structure includes a combustion device and a heat exchanger, and the heat exchanger and the radiator are connected in a circulation circuit so that hot water can be circulated, and the outgoing hot water downstream of the heat exchanger A hot water temperature setting means for setting the target temperature of the hot water, and a forward temperature sensor for detecting the temperature of the forward hot water flowing out from the heat exchanger on the downstream side of the heat exchanger, the hot water detected by the forward temperature sensor In a hot water circulating boiler in which the combustion amount is varied so that the temperature reaches the target temperature set by the going hot water temperature setting means, the temperature of the hot water radiated by the radiator is detected downstream of the radiator. A return temperature sensor is provided, and the return temperature sensor causes condensation on the heat exchanger.FirstWhen the temperature below the specified temperature is detected for a specified timeBeforeThe target temperature set by the hot water temperature setting means is the specified temperature.And increasing the number of rotations of the circulating pump for circulating the hot water until the temperature detected by the return temperature sensor is continuously detected for a predetermined time at a second predetermined temperature higher than the first predetermined temperature. As the time passes, the target temperature of the incoming hot water temperature is increased by a predetermined temperature, and the rotation speed of the circulation pump is increased.
[0008]
Further, in claim 4, the configuration is particularly the one in claim 3,When the temperature detected by the return temperature sensor is continuously detected for a predetermined time above the second predetermined temperature higher than the first predetermined temperature, the temperature detected by the return temperature sensor is continuously below the second predetermined temperature for a predetermined time. Until a predetermined time elapses, the target temperature of the incoming hot water temperature is decreased by a predetermined temperature and the rotation speed of the circulation pump is returned to the original value.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
  According to the first aspect of the present invention, the hot water circulating boiler 1 includes the combustion device 14 and the heat exchanger 13 and the heat exchanger 13 and the radiator 14 are connected to the circulating circuit 7 so that hot water can be circulated. A return temperature sensor 20 for detecting the temperature of hot water radiated by the radiator 4 is provided downstream of the radiator 4, and the return hot water temperature detected by the return temperature sensor 20 causes condensation on the heat exchanger 13. When the generated first predetermined temperature (for example, 30 ° C.) or lower is continued for a predetermined time, the combustion amount of the combustion device 14 is increased by one step in order to prevent condensation,The combustion amount of the combustion device is increased by one step each time the predetermined time elapses until the temperature detected by the return temperature sensor is continuously detected for a predetermined time at a second predetermined temperature higher than the first predetermined temperature. Repeatedly increase the amount of combustion,By increasing the amount of heat given to the circulating hot water, the temperature of the return hot water is raised to a temperature at which condensation does not occur, and the amount of combustion is increased to the high combustion amount side where condensation is unlikely to occur, so condensation is less likely to occur. .
[0010]
  According to the second aspect of the invention, the return hot water temperature detected by the return temperature sensor 19 as the combustion amount increases is equal to or higher than a second predetermined temperature (here, 40 ° C.) higher than the first predetermined temperature. If the temperature rises to 42 ° C. and a predetermined time or more elapses, the amount of combustion is reduced by one step to lower the return hot water temperature that has risen too much. Then, since the amount of combustion is decreased by one step every predetermined time until the return hot water temperature continues below the second predetermined temperature (here, 40 ° C.) for a predetermined time, the return hot water temperature is condensed on the heat exchanger 12. The temperature is controlled so as not to cause condensation, and although condensation is unlikely to occur, combustion is continued at a high combustion amount and energy is not wasted, preventing unnecessary temperature rise. This contributes to energy savings by optimizing operation and reducing wasted heat.
[0011]
  Further, according to the invention of claim 3, the combustion apparatus 14 and the heat exchanger 13 are provided, the heat exchanger 13 and the radiator 4 are connected in a circulation circuit 7 so that hot water can be circulated, and the heat exchange is performed. An outgoing hot water temperature setting means 29 for setting a target temperature of outgoing hot water downstream of the heat exchanger 13, and an outgoing temperature sensor 19 for detecting the temperature of hot water flowing out of the heat exchanger 13 on the downstream side of the heat exchanger 13. In the hot water circulating boiler 1, the amount of combustion is varied so that the hot water temperature detected by the forward temperature sensor 19 becomes the target temperature set by the forward warm water temperature setting means 29. A return temperature sensor 20 for detecting the temperature of the hot water radiated by the radiator 4 is provided on the downstream side, and the return temperature sensor 20 has a first predetermined temperature (for example, 30 ° C.) or less at which condensation occurs in the heat exchanger 13. For a given time When knowledge, raising the forward target temperature set by the hot water temperature setting means 29 by a few degrees (e.g. 5 ° C.)And increasing the number of rotations of the circulating pump for circulating the hot water until the temperature detected by the return temperature sensor is continuously detected for a predetermined time at a second predetermined temperature higher than the first predetermined temperature. Every time it passes, the target temperature of the hot water temperature is repeatedly raised to a predetermined temperature, soThe warm water temperature detected by the forward temperature sensor 19 becomes lower than the target temperature set by the forward warm water temperature setting means 29, and the combustion device 14 increases the amount of combustion. Therefore, by increasing the amount of heat given to the circulating warm water, the return warm water The temperature is raised to a temperature at which condensation does not occur.
  In this way, the amount of heat given to the circulating hot water is increased by increasing the target temperature of the outgoing hot water several degrees at a time, and the circulation rate of the circulating hot water is increased to reduce the amount of heat released by the radiator 4. As a result, the temperature of the return hot water is increased to a temperature where condensation does not occur, and the amount of combustion increases to the high combustion amount side where condensation is unlikely to occur, making condensation less likely to occur and returning to the target temperature of the outgoing hot water. The temperature is raised step by step while detecting the temperature of the hot water, so that the minimum amount of heat necessary to prevent condensation can be appropriately given and energy saving, and the load heated by the radiator 4 Against excessive heating.
[0012]
  According to the invention of claim 4, in the invention of claim 3,When the temperature detected by the return temperature sensor continuously detects a second predetermined temperature higher than the first predetermined temperature for a predetermined time, the target temperature of the incoming hot water is lowered by several degrees, and at the same time, the rotational speed of the circulation pump 16 Return to the original number of revolutions to reduce the return hot water temperature that has risen too much. Then, every time a predetermined time elapses until the return hot water temperature continues below the second predetermined temperature (40 ° C. in this case) for a predetermined time, the target temperature of the going hot water temperature is decreased by a predetermined temperature, and based on the rotation speed of the circulation pump By repeating the return, the temperature of the return hot water is controlled so as not to cause condensation in the heat exchanger 12, and the combustion is continued at a high combustion amount even though the condensation is unlikely to occur. The energy is not wasted, the unnecessary temperature rise is prevented, the operation is optimized, the wasted heat is suppressed, and the energy is saved.
[0013]
【Example】
A first embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a hot water circulation boiler, and hot water heated by the boiler 1 passes through an outgoing pipe 2 and an outgoing header 3 to a plurality of snow-melting radiators 4 embedded in the ground. Circulation which is diverted and circulates through each of the snow-melting radiators 4 and melts the snow accumulated on the sidewalk, etc., then merges at the return header 5, passes through the return pipe 6 and circulates and circulates again to the boiler 1. A circuit 7 is provided.
[0014]
Reference numeral 8 denotes a remote control device for instructing the start and stop of the operation of the boiler 1, which has an operation switch (not shown) and is connected to the snowfall sensor control unit 9. The snowfall sensor controller 9 includes a waterfall sensor 10 and an outside air temperature sensor (both not shown) that detect the presence or absence of snowfall, and a ground temperature embedded in the vicinity of the heat sink 4 for melting snow. The snow temperature sensor control unit 9 starts operation of the boiler 1 when the snow starts to fall, and then the ground temperature is raised to a certain temperature or more and the snow falls. Is stopped, the boiler 1 is instructed via the remote control device 8 to stop the operation of the boiler 1.
[0015]
Next, the boiler 1 will be described.
In FIG. 2, 12 is a circulation return port which is connected to the return pipe 6 and is used for melting snow by a heat sink 4 for melting snow, and returns to the warm water whose temperature has decreased, and 13 is a combustion device 14 at the bottom. A flow-through type heat exchanger that heats the hot water returned from the circulation return port 12, 15 is a mixing tank for equalizing the temperature of the hot water discharged from the heat exchanger 13, and 16 is the mixing A circulation pump is located in the circulation circuit 7 on the downstream side of the tank 15 and circulates hot water, and 17 is connected to the forward pipe 2, and the hot water heated by the heat exchanger 13 is sent to the radiator 4 for melting snow. A circulation outlet 18 for flowing, an expansion tank 18 for absorbing the expansion of the heated hot water, and 19 for detecting the temperature of the hot water that is provided downstream of the heat exchanger 13 and exits the heat exchanger 13. It is a forward temperature sensor that Is a return temperature sensor for detecting the temperature of the hot water which flows provided downstream of the radiator 4 to the heat exchanger 13.
[0016]
The combustion device 14 is vaporized by spraying kerosene with a fuel pump 23 on a vaporizer 22 heated by a vaporization heater 21, and mixing the vaporized gas with combustion air from a combustion blower 24. And the combustion gas passes through the once-through heat exchanger 13 to heat the hot water, and exhausts it from an exhaust top 26 provided on the top of the heat exchanger 13. The pump 23 and the combustion blower 24 are capable of capacity control to vary the amount of combustion.
Although the combustion device 14 using kerosene as the fuel is used here, the present invention is not limited to this, and a gas burner with a variable combustion amount using gas fuel may be used, and the heat exchanger 13 is a once-through type. However, the present invention is not limited to this, and a fin tube type heat exchanger may be used.
[0017]
A control device 27 controls the boiler 1 with a microcomputer 28 as a main body. The control device 27 receives inputs from the remote control device 8, the forward temperature sensor 19, and the return temperature sensor 20, and receives the vaporization heater 21, the fuel pump 23, and the combustion. The air blower 24 and the circulation pump 16 are driven and controlled. As one of the functions of the control device 27, dew condensation prevention control, which will be described later, is performed.
[0018]
Next, the operation of the dew condensation prevention control device of the first embodiment will be described based on the flowchart of FIG.
First, in step 1 (hereinafter abbreviated as S1), the temperature of the hot water that has been reduced in temperature by circulating through the snow-melting radiator 4 detected by the return temperature sensor 20 may cause condensation in the heat exchanger 13. It is checked whether it has continued for a predetermined time at a high first predetermined temperature (here, 30 ° C.) or less. If, for example, the return hot water temperature continues at 26 ° C. for a predetermined time, the process proceeds to S2 with “Yes” in S1, and it is checked whether the current combustion amount is the maximum combustion amount. If it is not the maximum combustion amount, it is “No” in S2, so the process proceeds to the next S3 and the combustion amount is increased by one step.
[0019]
Since the amount of combustion is increased in S3, the amount of heat given to the circulating hot water increases, and therefore the temperature of the hot water returning from the snowmelt radiator 4 also rises.
Here, for example, if the return hot water temperature rises by 3 ° C. and reaches 29 ° C., the return temperature of the hot water continues at a second predetermined temperature (here, 40 ° C.) higher than the first predetermined temperature in S4 for a predetermined time. Here, since the return hot water temperature is 29 ° C., “No” is obtained in S4, and the process returns to S1. In this S1, if the return hot water temperature is 29 ° C. and continues for a predetermined time, the steps of S2 to S4 are repeated again to increase the combustion amount, and by increasing the amount of heat given to the circulating hot water, the return hot water temperature does not cause condensation. In addition, the amount of combustion is increased toward the high combustion amount side where condensation is unlikely to occur, and therefore, condensation is further less likely to occur.
[0020]
At this time, if the return hot water temperature detected by the return temperature sensor 19 rises to 42 ° C. with the increase in the combustion amount and a predetermined time or more has elapsed, the result becomes “Yes” in S4, and the process proceeds to the next S5. Decrease the temperature of the return hot water by reducing it by one step. Then, S4 and S5 are repeated until the return hot water temperature continues below the second predetermined temperature (40 ° C. in this case) for a predetermined time, and the return hot water temperature returns to the step of S1, whereby the return hot water temperature causes condensation on the heat exchanger 12. By controlling the temperature so that it does not occur, it is difficult for condensation to occur, but it does not waste energy by continuing to burn at a high combustion amount, preventing unnecessary temperature rise. It will contribute to energy saving by optimizing operation and reducing the amount of wasted heat.
[0021]
Here, even if the combustion amount is increased to the maximum in order to prevent dew condensation, the return hot water temperature is less than a first predetermined temperature (here, 30 ° C.) that is highly likely to cause dew condensation in the heat exchanger 13. If the time continues, “Yes” is obtained in S2 and the process proceeds to the combustion stop step of S6, and the fuel pump 23 and the combustion blower 24 are stopped to stop the combustion, so that condensation has occurred. Therefore, it is possible to prevent the combustion device 14 and the heat exchanger 13 from being damaged and corroded without continuing the operation for a long time, and it is safe against any abnormality other than dew condensation.
[0022]
Therefore, it does not require a bypass pipe and a valve device for mixing the hot water of the forward pipe with the cold water of the return pipe as in the prior art, and is inexpensive and reliably prevents condensation of the heat exchanger 13 by simple control. The dew condensation water does not cause damage or corrosion of the combustion device 14 or the heat exchanger 13, and all the warm water circulates in the radiator 4. It does not decrease and has an excellent effect of not reducing the efficiency of snow melting or heating.
[0023]
Next, a second embodiment of the present invention will be described. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof is omitted.
In the second embodiment, the circulating pump 16 is of a variable speed type (for example, the speed of rotation can be varied by performing phase control or switching of the number of windings of the drive motor). The remote control device 8 is provided with an outgoing hot water temperature setting means 29, and the target temperature of the outgoing hot water flowing out from the heat exchanger 13 is set manually in several degrees (for example, in increments of 5 ° C.) or automatically according to the use conditions. It can be set.
[0024]
The control device 27 controls the fuel pump 23 and the combustion blower 24 based on the hot water temperature detected by the forward temperature sensor 19 so that the outgoing hot water temperature becomes the target temperature set by the outgoing hot water temperature setting means 29. Control to increase or decrease the amount of combustion. That is, if the warm water temperature detected by the forward temperature sensor 19 is lower than the target temperature set by the forward warm water temperature setting means 29, the combustion amount is increased, and if it is higher, the combustion amount is decreased.
[0025]
Next, the operation of the dew condensation prevention control device of the second embodiment will be described based on the flowchart of FIG.
First, in step 7, the temperature of the hot water that has been reduced in temperature by flowing through the snow-melting radiator 4 detected by the return temperature sensor 20 is a first predetermined temperature that is likely to cause condensation in the heat exchanger 13. It is checked whether or not (here, 30 ° C.) is continued for a predetermined time. For example, if the return hot water temperature continues at 26 ° C. for a predetermined time, the process proceeds to S8 with “Yes” in S7 to check whether the current target temperature of the outgoing hot water is the maximum set temperature. If it is not the maximum set temperature, “No” in S8, the process proceeds to the next S9, and the forward hot water temperature setting means 29 increases the target temperature of the forward hot water by several degrees. For example, the target temperature of the incoming hot water is 60 ° C. and is raised by 5 ° C. to 65 ° C. Further, in the next S10, the rotational speed of the circulation pump 16 is increased to increase the circulation speed of the hot water.
[0026]
Since the target temperature of the outgoing hot water is raised by several degrees in S9, the control device 27 increases the combustion amount so that the hot water temperature detected by the outgoing temperature sensor 19 becomes the target temperature (eg, 65 ° C. in this case). The amount of heat given to the circulating hot water is increased, and accordingly, the temperature of the hot water returning from the heat sink 4 for melting snow also rises.
[0027]
In addition, since the rotational speed of the circulation pump 16 is increased in S10, the time required to circulate through the snow melting radiator 4 is shortened, and the amount of heat radiated from the circulating hot water in the radiator 4 is reduced. The temperature of the hot water returning from the heat radiator 4 increases.
[0028]
Now, for example, suppose that the return hot water temperature has increased by 3 ° C. to 29 ° C. In the next S11, it is checked whether or not the return temperature of the hot water has continued for a predetermined time at a second predetermined temperature (here, 40 ° C.) higher than the first predetermined temperature. Here, since the return hot water temperature is 29 ° C., “No” is obtained in S11, and the process returns to S7. In S7, when the return hot water temperature is 29 ° C. and continues for a predetermined time, S8 to S11 are repeated again to increase the target temperature of the hot water by several degrees.
[0029]
In this way, by increasing the target temperature of the incoming hot water by several degrees, the amount of combustion is increased to increase the amount of heat given to the circulating hot water, and the circulation rate of the circulating hot water is increased to reduce the amount of heat released by the radiator 4. As a result, the temperature of the returned hot water is efficiently raised to a temperature at which condensation does not occur, and the amount of combustion increases to the high combustion amount side where condensation is unlikely to occur.
[0030]
In addition, the target temperature of the incoming hot water is returned and raised step by step while detecting the status of the hot water temperature, so that the minimum amount of heat necessary to prevent condensation can be given appropriately and energy saving. Thus, it is possible to prevent excessive heating with respect to the load heated by the radiator 4. (When the present invention is used not for melting snow but for heating, it has an excellent effect of preventing excessive heating.)
[0031]
If the return hot water temperature detected by the return temperature sensor 19 rises to 42 ° C. and a predetermined time or more has elapsed since the target temperature of the outgoing hot water is set high, “Yes” is obtained in S11, and the process proceeds to the next S12. Then, the target temperature of the incoming hot water is lowered by several degrees, and at the same time, the rotational speed of the circulation pump 16 is returned to the original rotational speed in S13 so as to lower the return hot water temperature that has increased too much. Then, S11 to S13 are repeated until the return hot water temperature continues below the second predetermined temperature (here, 40 ° C.) for a predetermined time, and the process returns to the step S7 again, whereby the return hot water temperature causes condensation on the heat exchanger 12. By controlling the temperature so that it does not occur, it is difficult for condensation to occur, but it does not waste energy by continuing to burn at a high combustion amount, preventing unnecessary temperature rise. It will contribute to energy saving by optimizing operation and reducing the amount of wasted heat.
[0032]
Here, even if the target temperature of the incoming hot water is set to the maximum set temperature (here, 80 ° C. is the maximum set temperature) to prevent condensation, the return hot water temperature is highly likely to cause condensation in the heat exchanger 13. If the first predetermined temperature (here, 30 ° C.) or lower is continued for a predetermined time, “Yes” is obtained in S8, the process proceeds to the combustion stop step in S14, and the fuel pump 23 and the combustion blower 24 are stopped. Since the combustion is stopped, it is possible to prevent the combustion device 14 and the heat exchanger 13 from being damaged or damaged without continuing the operation for a long time in a state where the condensation has occurred. Safe against any abnormalities.
[0033]
Therefore, it does not require a bypass pipe and a valve device for mixing the hot water of the forward pipe with the cold water of the return pipe as in the prior art, and is inexpensive and reliably prevents condensation of the heat exchanger 13 by simple control. The dew condensation water does not cause damage or corrosion of the combustion device 14 or the heat exchanger 13, and all the warm water circulates in the radiator 14. It does not decrease and has an excellent effect of not reducing the efficiency of snow melting or heating.
[0034]
Although both the first and second embodiments have been described as a hot water circulating boiler for melting snow, the present invention is not limited to this, and can be used for heating. For example, the radiator 4 meanders in a house floor material. The present invention is also useful for a floor heating system using hot water pipes arranged in the above manner, and a warm air heating apparatus that performs heating by a fan convector, a panel radiator, or the like installed indoors as the radiator 4.
[0035]
【The invention's effect】
  As aboveAccording to the first aspect of the present invention, each time the predetermined time elapses until the temperature detected by the return temperature sensor is continuously detected for a predetermined time at a second predetermined temperature higher than the first predetermined temperature. By increasing the amount of combustion by repeatedly increasing the amount of combustion by one step, the amount of heat given to the circulating hot water is increased to raise the temperature of the returned hot water to a temperature where condensation does not occur, and high combustion is unlikely to cause condensation Since the combustion amount is increased to the amount side, dew condensation is less likely to occur.
  Also,It does not require a bypass pipe and a valve device for mixing the hot water in the forward pipe with the cold water in the return pipe as in the prior art, and is inexpensive and can reliably prevent condensation in the heat exchanger through simple control. It does not cause damage or corrosion of the combustion device or heat exchanger due to condensed water, and all the hot water circulates in the radiator, so there is no significant decrease in the amount of heat released by the radiator. It has an excellent effect of not reducing the efficiency of snow melting and heating.
  According to the second aspect of the present invention, since the amount of combustion is decreased by one step every predetermined time until the return hot water temperature continues below the second predetermined temperature for a predetermined time, the return hot water temperature is set to the heat exchange temperature. The temperature is controlled so as not to cause dew condensation in the vessel, and although it is in a state where condensation does not occur easily, combustion is continued at a high combustion amount and energy is not wasted, and unnecessary temperature It prevents the rise and optimizes the operation to reduce the amount of heat that is wasted and contribute to energy saving.
  Further, according to the invention of claim 3, the amount of heat given to the circulating hot water is increased by repeatedly increasing the target temperature of the incoming hot water several times, thereby increasing the amount of heat given to the circulating hot water and increasing the circulation rate of the circulating hot water. By reducing the amount of heat released by the radiator, the temperature of the return water is efficiently raised to a temperature where condensation does not occur, and the amount of combustion increases to the high combustion amount side where condensation is unlikely to occur. In addition, the target temperature of the incoming hot water is returned and raised step by step while detecting the status of the hot water temperature, so that the minimum amount of heat necessary to prevent condensation can be given appropriately and energy saving. Therefore, it is possible to prevent excessive heating with respect to the load heated by the radiator.
  According to the invention of claim 4, the target temperature of the incoming hot water temperature is decreased by a predetermined temperature every time a predetermined time elapses until the return hot water temperature continues below the second predetermined temperature for a predetermined time, and the rotation of the circulation pump is also performed. By returning the number to the original value, the return hot water temperature is controlled to a temperature that does not cause condensation in the heat exchanger, and the combustion is continued at a high combustion amount even though condensation is unlikely to occur. Thus, energy is not wasted, and unnecessary temperature rise is prevented to optimize operation, thereby reducing the amount of heat that is wasted and contributing to energy saving.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a boiler according to the first embodiment.
FIG. 3 is a block diagram of the control apparatus of the first embodiment.
FIG. 4 is a flowchart showing the operation of the first embodiment.
FIG. 5 is a block diagram of a control apparatus according to the second embodiment.
FIG. 6 is a flowchart showing the operation of the second embodiment.
[Explanation of symbols]
1 boiler
4 radiators
7 Circulation circuit
13 Heat exchanger
14 Combustion device
19 Outward temperature sensor
20 Return temperature sensor
29 Outward hot water temperature setting means

Claims

In a hot water circulating boiler having a combustion device and a heat exchanger, wherein the heat exchanger and the radiator are connected so that hot water can be circulated in a circulation circuit, the hot water radiated by the radiator on the downstream side of the radiator comprising a return temperature sensor for detecting the temperature one combustion amount before Symbol combustion apparatus when said return Ri temperature sensor detects continuously the first predetermined temperature below the predetermined time condensation occurs in the heat exchanger The combustion amount of the combustion device is increased by one step each time the predetermined time elapses until the temperature detected by the return temperature sensor is continuously detected for a predetermined time at a second predetermined temperature higher than the first predetermined temperature. A dew condensation prevention control device for a hot water circulating boiler, characterized by increasing.

When the temperature detected by the return temperature sensor is continuously detected for a predetermined time above the second predetermined temperature higher than the first predetermined temperature, the temperature detected by the return temperature sensor is continuously below the second predetermined temperature for a predetermined time. 2. The dew condensation prevention control device for a hot water circulating boiler according to claim 1, wherein the combustion amount of the combustion device is reduced by one step every time a predetermined time elapses until the detection .

A forward hot water temperature setting means comprising a combustion device and a heat exchanger, wherein the heat exchanger and the radiator are connected so as to be able to circulate hot water in a circulation circuit, and a target temperature of the forward hot water downstream of the heat exchanger is set. And a forward temperature sensor for detecting the temperature of the outgoing warm water flowing out of the heat exchanger on the downstream side of the heat exchanger, and the hot water temperature detected by the outgoing temperature sensor is set by the outgoing hot water temperature setting means In the hot water circulation boiler in which the combustion amount is varied so as to reach the target temperature, a return temperature sensor for detecting the temperature of the hot water radiated by the radiator is provided downstream of the radiator, and the return temperature sensor is a first target temperature set in the previous SL heated hot water temperature setting means when a predetermined temperature or less is detected continuously for a predetermined time condensation in the heat exchanger occurs with increasing predetermined temperature circulates the hot water circulation Pump The target temperature of the incoming hot water temperature every time a predetermined time elapses until the temperature detected by the return temperature sensor is increased for a predetermined period of time until the temperature detected by the return temperature sensor is higher than the first predetermined temperature. The dew condensation prevention control device for a hot water circulation boiler is characterized in that the temperature of the circulation pump is increased and the rotation speed of the circulation pump is increased .

When the temperature detected by the return temperature sensor is continuously detected for a predetermined time above the second predetermined temperature higher than the first predetermined temperature, the temperature detected by the return temperature sensor is continuously below the second predetermined temperature for a predetermined time. The dew condensation of the hot water circulating boiler according to claim 3, wherein the target temperature of the incoming hot water temperature is decreased by a predetermined temperature and the rotational speed of the circulation pump is returned to the original state every time a predetermined time elapses until the detection. Prevention control device.