JP4710164B2

JP4710164B2 - Water heater

Info

Publication number: JP4710164B2
Application number: JP2001134809A
Authority: JP
Inventors: 真也中島; 智浩市川
Original assignee: 株式会社パロマ
Priority date: 2001-05-02
Filing date: 2001-05-02
Publication date: 2011-06-29
Anticipated expiration: 2021-05-02
Also published as: JP2002333212A

Description

【０００１】
【発明の属する技術分野】
本発明は、燃焼ガスにより通水を加熱する熱交換器を備えた湯沸器に関する。
【０００２】
【従来の技術】
従来から、台所等で主に使用される瞬間湯沸器としては、給水管及び出湯管が接続される熱交換器と、この熱交換器を加熱するバーナとを備え、バーナの燃焼により熱交換器で通水を加熱し、出湯管より出湯するものが一般的に知られている。
こうした湯沸器では、熱交換器にドレン（凝縮水）が発生することを防止するために、熱交換器からかなり高温の燃焼ガスを排出しており高い熱効率が得られていない。ドレンは、燃焼ガスが露点（およそ５０〜６０℃）以下になると発生するものであるから、原理的には、熱交換器でドレンを発生させずに露点まで熱交換して、燃焼ガス中の顕熱を回収することが可能である。しかしながら、熱交換器には通水部である伝熱管のような局所的な低温部が存在するので、実際には、低温部での部分的なドレン発生を防ぐために、燃焼ガスをかなりの高温で排出しなければならず、十分な顕熱を回収ができていない。
【０００３】
ところで、浴槽へ給湯したり、シャワー等へ大量にお湯を供給する大出力の給湯器では、燃焼ガス流路中の上流側に主に顕熱回収を目的とした主熱交換器を、下流側に主に潜熱回収を目的とした副熱交換器を設けて高い熱効率を得る潜熱回収型給湯器が一般的に知られている。
このような潜熱回収型給湯器では、副熱交換器で主熱交換器で回収できなかった顕熱に加え、燃焼ガス温が露点以下になるとドレンが発生するため潜熱も回収することができる。このため、燃焼ガス中のほとんどの熱エネルギー（顕熱＋潜熱）を回収できるので非常に高い熱効率を達成することが可能である。
【０００４】
【発明が解決しようとする課題】
しかしながら、凝縮したドレンが燃焼ガス中の硫黄（Ｓ）や窒素（Ｎ）と反応してｐＨ３程度の酸性になるため、上述したような潜熱回収型の器具では、下水道等の一般排水通路に排出する前に中和処理をしなければならず、中和器を備える等器具の構造が複雑になり製造コストが高くなってしまう。
そこで、本発明の湯沸器は上記課題を解決し、ドレン排水の中和処理が不要な高熱効率の湯沸器を提供することを目的とする。
【０００５】
【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記載の湯沸器は、
燃焼室内で燃料を燃焼するバーナと、
上記バーナの上方に設けられ、該バーナの燃焼ガスから顕熱を回収して伝熱管内の通水を加熱する主熱交換器と、
上記主熱交換器の上方に設けられ、該主熱交換器を通過した燃焼ガスから該主熱交換器で回収しきれなかった顕熱に加えて、潜熱を回収して伝熱管内の通水を加熱する副熱交換器と
を備えた湯沸器において、
上記副熱交換器の下方で上記主熱交換器の上方に設けられ、上記副熱交換器での潜熱回収によって発生したドレンを受けると共に、該ドレンを燃焼ガスにより加熱し上記主熱交換器と副熱交換器の間に形成される燃焼ガスの経路内で蒸発させてD該ドレンが気化蒸発するのに必要な熱量を該ドレンに付与するドレン蒸発器と、
上記ドレン蒸発器の横を流れる上記主熱交換器を通過した燃焼ガスを、上記副熱交換器の伝熱管に向けて案内する整流板と
を備えることを特徴とする。
【０００６】
また、本発明の請求項２記載の湯沸器は、上記請求項１記載の湯沸器において、
上記副熱交換器は、伝熱管が前後に２列で配列され、
上記整流板は、上記伝熱管の間に該伝熱管と平行に延設され、その断面が略Ｖ字状であることを要旨とする。
【０００７】
また、本発明の請求項３記載の湯沸器は、上記請求項１又は請求項２記載の湯沸器において、
上記ドレン蒸発器は、多孔質の耐熱・耐硝酸性の材料からなりドレンを受けて全体に浸透するドレン浸透体と、該ドレン浸透体を載置する浸透体載置板とを有し、該浸透体載置板の載置面には、複数の開口が設けられていることを要旨とする。
【０００８】
また、本発明の請求項４記載の湯沸器は、上記請求項１〜３のいずれか１項に記載の湯沸器において、
上記整流板には、燃焼ガスが通過する複数の開口が設けられていることを要旨とする。
【０００９】
また、本発明の請求項５記載の湯沸器は、上記請求項３又は請求項４記載の湯沸器において、
上記燃焼室の側壁に段部を形成し、該段部と上記浸透体載置板とで上記ドレン浸透体を挟み込んで該ドレン浸透体の抜け止めを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記載の湯沸器は、バーナの燃焼ガスが主熱交換器を加熱してから余熱で副熱交換器を加熱する。この際、燃焼ガスは、ドレン蒸発器も加熱する。
従って、燃焼ガスは、まず主熱交換器で冷却されて顕熱の多くが回収され、次に副熱交換器でドレンの発生する温度まで冷却されてドレンを発生して主熱交換器で回収できなかった顕熱に加え潜熱も回収される。
副熱交換器で発生したドレンは、ドレン蒸発器で受け取られ蒸発して燃焼ガス中に戻るため、湯沸器の外部へドレンは排出しない。この結果、ドレンを蒸発させるために、回収した潜熱分と同量の熱量が奪われるが、副熱交換器では、主熱交換器とは違いドレンが発生しないようにしておく必要がないために、器具から排出される燃焼ガスの排気温度を十分に下げることができ、主熱交換器で回収できなかった顕熱を回収できる。従って、器具全体としては燃焼ガスが持っている熱エネルギーのうちの大部分の顕熱を回収していることになる。
このようにして、ドレンを器具外に排出することなく、主熱交換器と副熱交換器とで効率良く通水を加熱して出湯する。
また、副熱交換器の下方にドレン蒸発器が設けられているので、副熱交換器の伝熱管への燃焼ガスの流れが悪くなっているが、整流板がドレン蒸発器の横を流れる燃焼ガスをこの伝熱管へ円滑に導くために、伝熱管にも燃焼ガスを良好に接触させることができ、熱交換が促進される。
【００１１】
また、本発明の請求項２記載の湯沸器は、前後２列に配列された副熱交換器の伝熱管の間に、断面が略Ｖ字状に形成された整流板を伝熱管と平行に延設することによって、両方の伝熱管に良好に燃焼ガスを導くことができ、副熱交換器での熱回収を十分に行うことができる。
【００１２】
また、本発明の請求項３記載の湯沸器は、浸透体載置板に載置されたドレン浸透体が副熱交換器から滴下してくるドレンを受け、受けられたドレンは多孔体であるドレン浸透体内全体に浸透していく。浸透体載置板には載置面に複数の開口が設けられているため、ドレン浸透体内を浸透体載置板との接触面まで浸透してきたドレンは、燃焼ガスと直接接触して加熱され、熱を無駄に使うことなく効率良く蒸発させられる。又、ドレン浸透体により広い範囲で蒸発するために部分的な突沸による異音も発生しない。
【００１３】
また、本発明の請求項４記載の湯沸器は、燃焼ガス流路中に設けられた整流板に燃焼ガスが通過する複数の開口を設けることにより、燃焼ガスの排気抵抗の低減がはかられる。
【００１４】
また、本発明の請求項５記載の湯沸器は、ドレン浸透体を燃焼室の側壁に形成された段部と浸透体載置板とではさむことにより、ドレン浸透体の抜け止めをすることができる。さらに、副熱交換器の伝熱管が貫通している燃焼室の側壁のまわりで発生し側壁を伝わって下に垂れていくドレンを、段部で側壁と接触しているドレン浸透体により確実に受けることができるので、ドレンが下方に位置する主熱交換器やバーナなどにたれることはない。
【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、以下本発明の湯沸器の好適な一実施形態について図１〜図６を用いて説明する。
【００１５】
図１は、一実施形態としての元止め式瞬間湯沸器１の概略構成図であり、図２は、湯沸器１の外観図であり、図３は、通水順路を示した図である。
器具正面には、点消火操作，水量調節及び出湯温調節するための操作ボタン２と、ガス量調節レバー３とが設けられる。操作ボタン２は、プッシュ式ボタンではあるものの回動自在に設けられ、点消火操作はプッシュ操作により、水量調節による出湯温調節は回し操作により行われる。器具本体４ケースには、操作ボタン２の周囲に温調用の目盛りが印刷されており、操作ボタン２のツマミ２ａをあわすことにより出湯温及び水量が無段階調節される。また、ガス量調節レバー３を左側の能力小の位置から右側の能力大の位置まで操作することによって供給ガス量は無断階調節される。
【００１６】
器具本体４内には、図１に示すように、燃焼室５が設けられ、燃焼室５内には、下から順に、燃料ガスを燃焼するバーナ６と、バーナ６からの燃焼ガスの顕熱の多くを回収するフィンチューブ式の主熱交換器７と、ドレンを受けて蒸発させるドレン蒸発器９と、燃焼ガスの流れの向きを変化させる整流板１０と、主熱交換器７で回収しきれなかった顕熱と潜熱とを回収する副熱交換器８とが設けられる。尚、副熱交換器８とドレン蒸発器９と整流板１０とは、副熱交換ユニット１１として、一体に形成されるものであり、これについての詳細は後述する。
燃焼室５の上面には、主熱交換器７，副熱交換器８で熱交換後の燃焼ガスを器体外へ排出する排気口１２が形成されており、この排気口１２は、器具本体４の上面に開口された排気穴１３に臨んでいる。尚、排気穴１３の上方に、器具外へ排出された燃焼ガスを前方に導くと共に、器具内にごみが落下するのを防ぐ図示しない略Ｌ字状の排気フードを設けても良い。
また、器具本体４及び燃焼室５の下面は、バーナ６の燃焼用空気を取り込むために開口されており、さらに、器具本体４の側面には給気口３０も設けられる。
【００１７】
水入口からの給水経路には、操作ボタン２による手動操作に連動して流路を開閉する水栓１４が設けられ、その下流には水圧応動装置１５が設けられる。水圧応動装置１５の下流側の流路には、操作ボタン２の回し操作と連動して出湯量を調節する水量調節軸１６が設けられる。
水量調節軸１６で流路は、２方向に分岐され、一方には副熱交換器８への給水管１７が、もう一方には主熱交換器７からの出湯管１８に接続されるバイパス管１９が設けられる。従って、副熱交換器８及び主熱交換器７を通ってきた湯（内胴通過水）とバイパス管１９を通ってきた水（バイパス水）との混合湯が器具から出湯することとなる。
【００１８】
図３に示すように、給水管１７は副熱交換器８として設けられ前後２列で平行に配列された副伝熱管８ａの入口に接続され、副伝熱管８ａの出口は燃焼室５を外側で巻回する巻回管２０の入口に接続され、巻回管２０の出口は主熱交換器７に設けられフィン７ｂを貫通して複数回蛇行する主伝熱管７ａの入口に接続され、主伝熱管７ａの出口は出湯管１８に接続される。
また、給水管１７の先端には、湯沸器１を使用後に凍結防止などの目的のために通水路中の水を抜くための分岐管２１が設けられており、この分岐管２１の先端には水抜き栓２２が設けられる。さらに、この湯沸器１の通水順路が、上方に位置する副伝熱管８ａ→下方に位置する巻回管２０→上方に位置する主伝熱管７ａとなるため、この分岐管２１のみで通水路中全ての水を抜こうとしても巻回管２０に水が溜まってしまうので、この水を抜くために巻回管２０の最も低い位置に水抜き管２３が設けられる。
【００１９】
ガス入口からバーナ６へのガス供給経路には、燃焼中に図示しない熱電対の熱起電力により開弁保持されるマグネット安全弁２４と、通水に関連して前述の水圧応動装置１５により通水時のみガス流路を開成する水圧応動弁２５と、操作ボタン２による手動操作に連動してガス流路を開閉する器具栓２６と、ガス量調節レバー３の手動操作と連動してガス供給量を調節するガス量調節軸２７が設けられる。
【００２０】
次に、副熱交換器８とドレン蒸発器９と整流板１０とからなる副熱交換ユニット１１について図４〜図６を用いて詳述する。図４は副熱交換ユニット１１の上面図、図５は正面図、図６は図４及び図５中の一点鎖線Ａ−Ａでの断面図である。尚、図４中においてはドレン蒸発器９が省略してあり、図５中においては整流板１０及び燃焼室５を形成するための前板３１と後板３２が省略してある。
副熱交換器８は、前後２列で平行に配列された前副伝熱管８ａＡと後副伝熱管８ａＢとから構成されている。以下説明にあたり、前副伝熱管８ａＡと後副伝熱管８ａＢとを区別しない場合には、副伝熱管８ａという。副伝熱管８ａの両端は、燃焼室５の側壁を貫通して突出しており、その一端で曲管２８によって接合される。そして後副伝熱管８ａＢの別の一端に給水管１７が接続され、前副伝熱管８ａＡの別の一端に巻回管２０が接続される。
【００２１】
前副伝熱管８ａＡと後副伝熱管８ａＢの真下には、それぞれ、副伝熱管８ａで燃焼ガスの潜熱を回収することによって発生したドレンを受けて、受けたドレンを燃焼ガスにより加熱して蒸発させるドレン蒸発器９が設けられる。ドレン蒸発器９は、副伝熱管８ａから滴下してくるドレンを受けるドレン浸透体９ａと、ドレン浸透体９ａを支える浸透体載置板９ｂとからなる。ドレン浸透体９ａは、耐熱及び耐ドレン性に優れた多孔質のセラミックス製であり、浸透体載置板９ｂは、ステンレス製の板をＶ字状に折り曲げてその両端を燃焼室５の側壁に接合して形成される。そして、ドレン浸透体９ａは、この浸透体載置板９ｂの上に２個づつ載置される。また、浸透体載置板９ｂには、複数の蒸発開口９ｃが設けられる。
【００２２】
副伝熱管８ａより下方の燃焼室５の側壁には、その横幅が大きくなるように段部２９が形成されており、この段部２９と浸透体載置板９ｂとでドレン浸透体９ａを挟み込んで抜け止めする。
整流板１０は、溶融アルミニウムめっき鋼板を略Ｖ字状に形成し、前後２列の副伝熱管８ａの中間位置に、副伝熱管８ａと平行に延設され、その両端が燃焼室５の側壁に接合される構成である。この整流板１０には、燃焼ガスを通過させる複数の通気孔１０ａが開口される。
このような副熱交換ユニット１１は、一体的に組み立てられたユニットとなっており、主熱交換器７の上に載置され、ビスでとめて固定されるものである。
【００２３】
上述したように構成された湯沸器１では、操作ボタン２の手動操作と連動して器具栓２６及び水栓１４が開き通水が開始される。水入口より流入した水（図中破線矢印）は、水栓１４、水圧応動装置１５を通り水量調節軸１６より、一方は給水管１７を経て副熱交換器８、巻回管２０、主熱交換器７を通り出湯管１８へ、他方はバイパス管１９を通って出湯管１８からの湯と混合される。
また、水圧応動装置１５に通水されると水圧応動弁２５とマグネット安全弁２４が開弁され、バーナ６にガスが供給され、図示しない電極からの連続スパークにより着火する。バーナ６の燃焼中は、図示しない熱電対の熱起電力によりマグネット安全弁２４の開弁状態が維持され、燃焼が維持される。
【００２４】
燃料ガスのバーナ６での燃焼に伴い、器具本体４の下面の開口や、側面に設けられた給気口３０より外気が器具本体４内に吸引され、燃焼室５下面の開口を通ってバーナ６へ導入されて燃焼用空気として燃焼に供される。
バーナ６の炎口近傍では混合気が燃焼して火炎を形成し、主熱交換器７の上流近傍に至る間に燃焼が完結（完全燃焼）する。
主熱交換器７を燃焼ガス流路の上流に設け、副熱交換器８を燃焼ガス流路の下流に設けたため、バーナ６からの高温の燃焼ガスが、自然ドラフト力により主熱交換器７の各フィン７ｂ間を貫流し良好に熱交換し、これにより温度の下がった燃焼ガスが副熱交換器８においても熱交換して排気口１２から器具の外へ排出される。また、燃焼ガスは、主熱交換器７に入る前に、燃焼室５の外側を巻回している巻回管２０でも熱交換して通水を加熱する。
【００２５】
主熱交換器７及び巻回管２０では、ドレンを発生させずに燃焼ガスから顕熱だけを回収しているわけであるが、通水部である主伝熱管７ａのような局所的な低温部が存在するので、このような低温部での部分的なドレン発生を防止するために燃焼ガスの排気温度が十分下がるまで熱交換できず、潜熱だけではなく顕熱の一部も回収できない。
一方、副熱交換器８の副伝熱管８ａでは、主熱交換器７を通過してきた燃焼ガスをさらに冷却し、ドレンを発生させて潜熱を回収するわけであるが、この際、主熱交換器７及び巻回管２０で回収しきれなかった顕熱も回収する。
発生したドレンは、副伝熱管８ａの真下に設けられたドレン蒸発器９で受けられ、主熱交換器７を通過してきた燃焼ガスによって加熱され蒸発する。この際、回収した潜熱と同量の熱量を燃焼ガス中へ放出してしまうが、副熱交換器８では、主熱交換器７及び巻回管２０とは違いドレンが発生しないようにしておく必要がないため、器具から排出される燃焼ガスの排気温度が十分に下がるまで熱交換して、主熱交換器７及び巻回管２０で回収できなかった顕熱を回収できるので、器具全体としては、燃焼ガス中の大部分の顕熱を回収していることになる。従って、ドレンを排出せずに、高熱効率を達成できる。
【００２６】
また、副伝熱管８ａの真下にドレン蒸発器９が設けられているために、副伝熱管８ａへの燃焼ガスの流れが悪くなってしまうが、整流板１０によって燃焼ガスの流れの向きが変えられて副伝熱管８ａへも燃焼ガスが円滑に流れる。このため、副伝熱管８ａにも燃焼ガスが良好に接触して熱交換が促進される。
また、バーナ６の燃焼用空気を自然ドラフト力のみによって取り込んでいるこのような自然燃焼式の器具では、ファンによって強制的に取り込む強制燃焼式の器具と比べ、燃焼ガス流路中に整流板１０のような異物を設けることによる燃焼ガスの排気抵抗の増大が大きな問題となるが、整流板１０に燃焼ガスが通過する通気穴１０ａを複数設けることにより、このような排気抵抗の増大を抑制しバーナ６の燃焼状態を良好に維持することができる。
【００２７】
多孔質のドレン浸透体９ａに滴下したドレンは、ドレン浸透体９ａ内全体に浸透していく。そして、ドレン浸透体９ａ内を浸透体載置板９ｂとの接触面まで浸透してきたドレンは、浸透体載置板９ｂに複数の蒸発開口９ｃが設けられているため、燃焼ガスと直接接触して加熱されて、熱を無駄に使うことなく良好に蒸発する。又、ドレン浸透体９ａにより広い範囲で蒸発させるので、部分的な突沸による異音の発生も防止できる。
【００２８】
しかも、ドレン浸透体９ａを燃焼室５の側壁に形成された段部２９と浸透体載置板９ｂとではさむことにより、副熱交換器８の伝熱管が貫通している燃焼室５の側壁のまわりで発生し側壁を伝わって下に垂れていくドレンを、側壁の段部２９で側壁と接触しているドレン浸透体９ａにより確実に受けることができるので、ドレンが下方に位置する主熱交換器７やバーナ６などに垂れることはない。
【００２９】
さらに、給水流路中で最も低温の水を副伝熱管８ａに通水することで、大きな温度差の中で、効率良く燃焼ガス中の潜熱及び顕熱を回収できる。さらに、副伝熱管８ａでの加熱により冷水は予熱されるため、巻回管２０にまかれた燃焼室５の内壁でのドレン発生を抑制できる。そして、最後に主伝熱管７ａに給水流路中で最も高温の湯を通水できるので、そこでのドレン発生を効果的に抑制できる。
【００３０】
以上本発明の実施形態について説明したが、本発明はこうした実施形態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。
【００３１】
【発明の効果】
以上詳述したように、本発明の請求項１記載の湯沸器によれば、副熱交換器で発生したドレンをドレン蒸発器で蒸発させるため、ドレンを器具外へ排出せずドレンの中和処理が不要で、かつ燃焼ガス中の大部分の顕熱を回収できるために熱効率が非常に高くなる。そして、ドレン蒸発器によって燃焼ガスの流れが妨害される副熱交換器の伝熱管へも円滑に燃焼ガスを導くことができるので、そこでの熱交換が促進されて、さらに熱効率を向上させることができる。
【００３２】
更に、本発明の請求項２記載の湯沸器によれば、副熱交換器と整流板とを簡単な構造で実施することができるので、湯沸器を製造するコストを抑制できる。
【００３３】
更に、本発明の請求項３記載の湯沸器によれば、ドレンを燃焼ガスによって直接加熱することができるため、ドレンを良好に蒸発させることができる。
【００３４】
更に、本発明の請求項４記載の湯沸器によれば、燃焼ガスの排気抵抗を低減し、バーナの燃焼を良好に維持することができる。
【００３５】
更に、本発明の請求項５記載の湯沸器によれば、燃焼室の側壁を伝わって下方へ流れ落ちるドレンをドレン浸透体で確実に受けることができるため、主熱交換器やバーナがドレンによって腐食されることを防止できる。
【図面の簡単な説明】
【図１】本実施形態の湯沸器の概略構成図である。
【図２】本実施形態の湯沸器の外観図である。
【図３】本実施形態の湯沸器の通水順路を示した図である。
【図４】本実施形態の副熱交換ユニットの上面図である。
【図５】本実施形態の副熱交換ユニットの正面図である。
【図６】本実施形態の副熱交換ユニットの断面図である。
【符号の説明】
１…湯沸器、５…燃焼室、６…バーナ、７…主熱交換器、７ａ…主伝熱管、８…副熱交換器、８ａ…副伝熱管、８ａＡ…前副伝熱管、８ａＢ…後副伝熱管、９…ドレン蒸発器、９ａ…ドレン浸透体、９ｂ…浸透体載置板、９ｃ…蒸発開口、１０…整流板、１０ａ…通気孔、２９…段部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water heater provided with a heat exchanger that heats water through combustion gas.
[0002]
[Prior art]
Conventionally, as an instantaneous water heater mainly used in a kitchen or the like, a heat exchanger to which a water supply pipe and a hot water discharge pipe are connected and a burner for heating the heat exchanger are provided, and heat exchange is performed by burning the burner. It is generally known that the water is heated by a vessel and discharged from a discharge pipe.
In such a water heater, in order to prevent drain (condensate) from being generated in the heat exchanger, a considerably high-temperature combustion gas is discharged from the heat exchanger, and high thermal efficiency is not obtained. Since the drain is generated when the combustion gas falls below the dew point (approximately 50 to 60 ° C.), in principle, heat is exchanged to the dew point without generating a drain in the heat exchanger, It is possible to recover sensible heat. However, since the heat exchanger has a local low temperature part such as a heat transfer tube that is a water flow part, in practice, in order to prevent partial drain generation in the low temperature part, the combustion gas is considerably heated. It must be exhausted and sufficient sensible heat cannot be recovered.
[0003]
By the way, in a high-output water heater that supplies hot water to a bathtub or supplies a large amount of hot water to a shower or the like, a main heat exchanger mainly for the purpose of recovering sensible heat is disposed downstream of the combustion gas passage. In general, a latent heat recovery type water heater is known in which an auxiliary heat exchanger mainly for the purpose of recovering latent heat is provided to obtain high thermal efficiency.
In such a latent heat recovery type water heater, in addition to the sensible heat that could not be recovered by the main heat exchanger in the sub heat exchanger, drainage is generated when the combustion gas temperature falls below the dew point, so that latent heat can also be recovered. For this reason, since most of the thermal energy (sensible heat + latent heat) in the combustion gas can be recovered, it is possible to achieve very high thermal efficiency.
[0004]
[Problems to be solved by the invention]
However, since the condensed drain reacts with sulfur (S) and nitrogen (N) in the combustion gas and becomes acidic at about pH 3, the latent heat recovery type appliance as described above discharges into a general drainage passage such as a sewer. The neutralization process must be performed before the operation, and the structure of the instrument such as a neutralizer becomes complicated and the manufacturing cost increases.
Then, the water heater of this invention solves the said subject, and aims at providing the high heat efficiency water heater which does not require the neutralization process of drain waste_water | drain.
[0005]
[Means for Solving the Problems]
The water heater according to claim 1 of the present invention for solving the above-mentioned problems is
A burner that burns fuel in the combustion chamber;
A main heat exchanger provided above the burner for recovering sensible heat from the combustion gas of the burner and heating the water flow in the heat transfer tube;
Provided above the main heat exchanger, in addition to the sensible heat that could not be recovered by the main heat exchanger from the combustion gas that passed through the main heat exchanger, the latent heat was recovered and the water flow in the heat transfer tube A water heater with a secondary heat exchanger for heating
Provided above the main heat exchanger below the auxiliary heat exchanger, together with the receiving drain generated by the latent heat recovery in the secondary heat exchanger, and the main heat exchanger the drain is heated by the combustion gases A drain evaporator that evaporates in the path of the combustion gas formed between the auxiliary heat exchangers, and that gives the drain the amount of heat necessary for vaporizing and evaporating the drain;
And a rectifying plate for guiding the combustion gas that has passed through the main heat exchanger flowing beside the drain evaporator toward the heat transfer tube of the sub heat exchanger.
[0006]
Moreover, the water heater according to claim 2 of the present invention is the water heater according to claim 1,
In the sub heat exchanger, the heat transfer tubes are arranged in two rows at the front and rear,
The gist of the current plate is that it extends in parallel with the heat transfer tube between the heat transfer tubes and has a substantially V-shaped cross section.
[0007]
The water heater according to claim 3 of the present invention is the water heater according to claim 1 or 2,
The drain evaporator includes a drain permeator made of a porous heat-resistant / nitric acid-resistant material and permeating the entire drain, and a permeator mounting plate on which the drain permeator is mounted, The gist is that a plurality of openings are provided on the mounting surface of the penetrating body mounting plate.
[0008]
Moreover, the water heater according to claim 4 of the present invention is the water heater according to any one of claims 1 to 3,
The gist is that the rectifying plate is provided with a plurality of openings through which combustion gas passes.
[0009]
Moreover, the water heater according to claim 5 of the present invention is the water heater according to claim 3 or claim 4, wherein
The gist is to form a step portion on the side wall of the combustion chamber and prevent the drain permeation body from slipping by sandwiching the drain permeation body between the step portion and the permeation body mounting plate.
[0010]
The water heater according to claim 1 of the present invention having the above configuration heats the auxiliary heat exchanger with the residual heat after the combustion gas of the burner heats the main heat exchanger. At this time, the combustion gas also heats the drain evaporator.
Therefore, the combustion gas is first cooled by the main heat exchanger and most of the sensible heat is recovered, then cooled to the temperature at which drain is generated by the auxiliary heat exchanger to generate drain, and recovered by the main heat exchanger. In addition to the sensible heat that was not possible, latent heat is also recovered.
Since the drain generated in the auxiliary heat exchanger is received by the drain evaporator and evaporated to return to the combustion gas, the drain is not discharged to the outside of the water heater. As a result, in order to evaporate the drain, the same amount of heat as the recovered latent heat is deprived, but unlike the main heat exchanger, it is not necessary to keep the drain from being generated in the auxiliary heat exchanger. The exhaust temperature of the combustion gas discharged from the instrument can be lowered sufficiently, and the sensible heat that could not be recovered by the main heat exchanger can be recovered. Therefore, as a whole instrument, most of the sensible heat of the thermal energy of the combustion gas is recovered.
In this way, the water is efficiently heated and discharged by the main heat exchanger and the sub heat exchanger without discharging the drain outside the appliance.
In addition, since the drain evaporator is provided below the auxiliary heat exchanger, the flow of the combustion gas to the heat transfer tube of the auxiliary heat exchanger is deteriorated, but the combustion that the rectifying plate flows beside the drain evaporator In order to smoothly guide the gas to the heat transfer tube, the combustion gas can be brought into good contact with the heat transfer tube, and heat exchange is promoted.
[0011]
Further, in the water heater according to claim 2 of the present invention, a rectifying plate having a substantially V-shaped cross section is parallel to the heat transfer tube between the heat transfer tubes of the auxiliary heat exchangers arranged in two rows. Therefore, the combustion gas can be guided well to both heat transfer tubes, and the heat recovery in the auxiliary heat exchanger can be sufficiently performed.
[0012]
In the water heater according to claim 3 of the present invention, the drain penetrating body placed on the penetrating body placing plate receives drain dripped from the auxiliary heat exchanger, and the received drain is a porous body. It penetrates the entire drainage body. Since the penetrating body mounting plate has a plurality of openings on the mounting surface, the drain that has permeated the drain penetrating body up to the contact surface with the penetrating body mounting plate is heated in direct contact with the combustion gas. It can be evaporated efficiently without wasting heat. Further, since the drain permeation body evaporates in a wide range, no abnormal noise due to partial bumping occurs.
[0013]
In the water heater according to claim 4 of the present invention, the exhaust resistance of the combustion gas is reduced by providing a plurality of openings through which the combustion gas passes in a rectifying plate provided in the combustion gas flow path. It is.
[0014]
In the water heater according to claim 5 of the present invention, the drain permeator is prevented from coming off by sandwiching the drain permeator between the step formed on the side wall of the combustion chamber and the permeate body mounting plate. Can do. Furthermore, the drain that is generated around the side wall of the combustion chamber through which the heat transfer tube of the auxiliary heat exchanger penetrates and hangs down through the side wall is surely secured by the drain permeator that is in contact with the side wall at the stepped portion. Since it can be received, the drain does not lean on the main heat exchanger or burner located below.
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 with reference to FIGS.
[0015]
FIG. 1 is a schematic configuration diagram of a stop-type instantaneous water heater 1 as an embodiment, FIG. 2 is an external view of the water heater 1, and FIG. 3 is a diagram showing a water flow route. is there.
On the front side of the appliance, there are provided an operation button 2 for adjusting the point of fire, adjusting the amount of water and adjusting the temperature of the hot water, and a gas amount adjusting lever 3. Although the operation button 2 is a push type button, it is rotatably provided. The point-extinguishing operation is performed by a push operation, and the hot water temperature adjustment by adjusting the amount of water is performed by a turning operation. A scale for temperature adjustment is printed around the operation button 2 on the instrument body 4 case, and the hot water temperature and the amount of water are adjusted steplessly by turning the knob 2a of the operation button 2. Further, by operating the gas amount adjusting lever 3 from the position of the small capacity on the left side to the position of the large capacity on the right side, the amount of supplied gas is adjusted without permission.
[0016]
As shown in FIG. 1, a combustion chamber 5 is provided in the instrument body 4. In the combustion chamber 5, a burner 6 that burns fuel gas in order from the bottom, and sensible heat of the combustion gas from the burner 6. Is recovered by a finned tube main heat exchanger 7 that collects most of the fuel, a drain evaporator 9 that receives and evaporates the drain, a rectifying plate 10 that changes the flow direction of the combustion gas, and the main heat exchanger 7. An auxiliary heat exchanger 8 is provided for recovering sensible heat and latent heat that could not be obtained. The auxiliary heat exchanger 8, the drain evaporator 9, and the rectifying plate 10 are integrally formed as the auxiliary heat exchange unit 11, and details thereof will be described later.
On the upper surface of the combustion chamber 5, there is formed an exhaust port 12 for discharging the combustion gas after heat exchange by the main heat exchanger 7 and the sub heat exchanger 8 to the outside of the device body. It faces the exhaust hole 13 opened on the upper surface of the. In addition, a substantially L-shaped exhaust hood (not shown) may be provided above the exhaust hole 13 to guide the combustion gas discharged outside the instrument forward and prevent the dust from falling into the instrument.
Further, the lower surfaces of the instrument body 4 and the combustion chamber 5 are opened to take in combustion air for the burner 6, and an air supply port 30 is also provided on the side surface of the instrument body 4.
[0017]
In the water supply path from the water inlet, a faucet 14 that opens and closes the flow path in conjunction with a manual operation by the operation button 2 is provided, and a water pressure responsive device 15 is provided downstream thereof. In the flow path on the downstream side of the water pressure actuator 15, a water amount adjusting shaft 16 that adjusts the amount of hot water in conjunction with the turning operation of the operation button 2 is provided.
The water flow adjusting shaft 16 branches the flow path in two directions, one side being a water supply pipe 17 to the auxiliary heat exchanger 8 and the other being a bypass pipe connected to the hot water outlet pipe 18 from the main heat exchanger 7. 19 is provided. Therefore, the hot water that has passed through the auxiliary heat exchanger 8 and the main heat exchanger 7 (inner trunk passing water) and the water that has passed through the bypass pipe 19 (bypass water) is discharged from the appliance.
[0018]
As shown in FIG. 3, the water supply pipe 17 is provided as an auxiliary heat exchanger 8 and is connected to the inlet of the auxiliary heat transfer pipe 8 a arranged in parallel in two rows in the front and rear, and the outlet of the auxiliary heat transfer pipe 8 a extends outside the combustion chamber 5. The outlet of the winding tube 20 is connected to the inlet of the main heat transfer tube 7a which is provided in the main heat exchanger 7 and snakes through the fins 7b a plurality of times. The outlet of the heat transfer tube 7 a is connected to the hot water discharge pipe 18.
Further, a branch pipe 21 is provided at the tip of the water supply pipe 17 for draining water in the water passage for the purpose of preventing freezing after the water heater 1 is used. Is provided with a drain plug 22. Further, since the water flow path of the water heater 1 is the sub heat transfer pipe 8a located at the upper side → the winding pipe 20 located at the lower side → the main heat transfer pipe 7a located at the upper side, the passage is made only by the branch pipe 21. Even if all the water in the water channel is to be drained, the water is accumulated in the winding tube 20, so that the water draining tube 23 is provided at the lowest position of the winding tube 20 in order to drain this water.
[0019]
In the gas supply path from the gas inlet to the burner 6, water is passed by the magnet safety valve 24 that is held open by the thermoelectromotive force of a thermocouple (not shown) during combustion, and the water pressure responsive device 15 related to water flow. Only when the water pressure responsive valve 25 opens the gas flow path, the instrument plug 26 opens and closes the gas flow path in conjunction with the manual operation of the operation button 2, and the gas supply amount in conjunction with the manual operation of the gas amount adjusting lever 3. A gas amount adjusting shaft 27 for adjusting the gas amount is provided.
[0020]
Next, the auxiliary heat exchange unit 11 including the auxiliary heat exchanger 8, the drain evaporator 9, and the rectifying plate 10 will be described in detail with reference to FIGS. 4 is a top view of the auxiliary heat exchange unit 11, FIG. 5 is a front view, and FIG. 6 is a cross-sectional view taken along one-dot chain line AA in FIGS. In FIG. 4, the drain evaporator 9 is omitted, and in FIG. 5, the front plate 31 and the rear plate 32 for forming the rectifying plate 10 and the combustion chamber 5 are omitted.
The auxiliary heat exchanger 8 includes a front auxiliary heat transfer tube 8aA and a rear auxiliary heat transfer tube 8aB which are arranged in parallel in two rows. In the following description, when the front auxiliary heat transfer tube 8aA and the rear auxiliary heat transfer tube 8aB are not distinguished, they are referred to as auxiliary heat transfer tubes 8a. Both ends of the auxiliary heat transfer tube 8a protrude through the side wall of the combustion chamber 5, and are joined by bent tubes 28 at one end thereof. Then, the water supply pipe 17 is connected to another end of the rear auxiliary heat transfer pipe 8aB, and the wound pipe 20 is connected to another end of the front auxiliary heat transfer pipe 8aA.
[0021]
Under the front auxiliary heat transfer tube 8aA and the rear auxiliary heat transfer tube 8aB, the drain generated by collecting the latent heat of the combustion gas is received by the auxiliary heat transfer tube 8a, and the received drain is heated by the combustion gas and evaporated. A drain evaporator 9 is provided. The drain evaporator 9 includes a drain penetrating body 9a that receives drain dripping from the sub heat transfer tube 8a, and a penetrating body mounting plate 9b that supports the drain penetrating body 9a. The drain penetrating body 9a is made of porous ceramics having excellent heat resistance and drain resistance, and the penetrating body mounting plate 9b is formed by bending a stainless steel plate into a V shape and having both ends thereof on the side wall of the combustion chamber 5. It is formed by joining. And two drain penetration bodies 9a are mounted on this penetration body mounting board 9b. The penetrating body mounting plate 9b is provided with a plurality of evaporation openings 9c.
[0022]
A step portion 29 is formed on the side wall of the combustion chamber 5 below the auxiliary heat transfer tube 8a so as to increase the lateral width thereof, and the drain permeator 9a is sandwiched between the step portion 29 and the permeator mounting plate 9b. To prevent it from coming off.
The rectifying plate 10 is formed of a hot-dip aluminized steel plate in a substantially V shape, and extends in parallel with the auxiliary heat transfer tubes 8 a at intermediate positions between the two rows of auxiliary heat transfer tubes 8 a. It is the structure joined to. The rectifying plate 10 has a plurality of vent holes 10a through which combustion gas passes.
Such a sub heat exchange unit 11 is an integrally assembled unit, and is placed on the main heat exchanger 7 and fixed with screws.
[0023]
In the water heater 1 configured as described above, the instrument plug 26 and the faucet 14 are opened in conjunction with the manual operation of the operation button 2 and water passage is started. The water flowing in from the water inlet (broken arrow in the figure) passes through the faucet 14 and the water pressure actuator 15 and from the water amount adjusting shaft 16, one through the water supply pipe 17, and the auxiliary heat exchanger 8, the winding pipe 20 and the main heat. The hot water from the hot water discharge pipe 18 is mixed with the hot water supply pipe 18 through the exchanger 7 and the other through the bypass pipe 19.
Further, when water is passed through the water pressure responsive device 15, the water pressure responsive valve 25 and the magnet safety valve 24 are opened, gas is supplied to the burner 6, and ignition is performed by continuous spark from an electrode (not shown). During combustion of the burner 6, the open state of the magnet safety valve 24 is maintained by the thermoelectromotive force of a thermocouple (not shown), and combustion is maintained.
[0024]
As the fuel gas burns in the burner 6, outside air is sucked into the instrument body 4 from the opening on the lower surface of the instrument body 4 and the air supply port 30 provided on the side surface, and passes through the opening on the lower surface of the combustion chamber 5. 6 is used for combustion as combustion air.
In the vicinity of the flame outlet of the burner 6, the air-fuel mixture burns to form a flame, and the combustion is completed (complete combustion) while reaching the upstream vicinity of the main heat exchanger 7.
Since the main heat exchanger 7 is provided upstream of the combustion gas flow path and the sub heat exchanger 8 is provided downstream of the combustion gas flow path, the high-temperature combustion gas from the burner 6 is converted into the main heat exchanger 7 by natural draft force. Heat flows through the fins 7b and exchanges heat well. As a result, the combustion gas whose temperature has decreased is also exchanged in the auxiliary heat exchanger 8 and discharged from the exhaust port 12 to the outside of the appliance. Further, before entering the main heat exchanger 7, the combustion gas heat-exchanges the water by exchanging heat also in the winding tube 20 wound around the outside of the combustion chamber 5.
[0025]
In the main heat exchanger 7 and the winding tube 20, only sensible heat is recovered from the combustion gas without generating drain. However, a local low temperature such as the main heat transfer tube 7a which is a water passage is used. Therefore, heat cannot be exchanged until the exhaust temperature of the combustion gas is sufficiently lowered to prevent partial drain generation in such a low temperature portion, and not only latent heat but also part of sensible heat cannot be recovered.
On the other hand, in the auxiliary heat exchanger tube 8a of the auxiliary heat exchanger 8, the combustion gas that has passed through the main heat exchanger 7 is further cooled to generate drainage and recover latent heat. The sensible heat that could not be recovered by the vessel 7 and the winding tube 20 is also recovered.
The generated drain is received by a drain evaporator 9 provided directly below the sub heat transfer tube 8a, and is heated and evaporated by the combustion gas passing through the main heat exchanger 7. At this time, the same amount of heat as the recovered latent heat is released into the combustion gas. However, unlike the main heat exchanger 7 and the winding tube 20, the auxiliary heat exchanger 8 is configured not to generate drainage. Since it is not necessary, heat exchange can be performed until the exhaust temperature of the combustion gas exhausted from the instrument is sufficiently lowered, and sensible heat that cannot be recovered by the main heat exchanger 7 and the winding tube 20 can be recovered. Means that most of the sensible heat in the combustion gas is recovered. Therefore, high thermal efficiency can be achieved without draining.
[0026]
Further, since the drain evaporator 9 is provided directly under the auxiliary heat transfer tube 8a, the flow of the combustion gas to the auxiliary heat transfer tube 8a is deteriorated, but the flow direction of the combustion gas is changed by the rectifying plate 10. Thus, the combustion gas smoothly flows also to the auxiliary heat transfer tube 8a. For this reason, combustion gas contacts well also to the sub-heat-transfer tube 8a, and heat exchange is accelerated | stimulated.
Further, in such a natural combustion type appliance in which the combustion air of the burner 6 is taken in only by a natural draft force, the rectifying plate 10 is placed in the combustion gas flow path as compared with a forced combustion type appliance forcibly taken in by a fan. Although the increase in the exhaust resistance of the combustion gas due to the provision of such foreign matters is a major problem, the increase in the exhaust resistance is suppressed by providing a plurality of vent holes 10a through which the combustion gas passes in the rectifying plate 10. The combustion state of the burner 6 can be maintained satisfactorily.
[0027]
The drain dripped onto the porous drain penetrating body 9a penetrates into the entire drain penetrating body 9a. The drain that has permeated the drain permeator 9a up to the contact surface with the permeator mounting plate 9b is in direct contact with the combustion gas because the permeator mounting plate 9b is provided with a plurality of evaporation openings 9c. Heats up and evaporates well without wasting heat. Further, since the drain penetrating body 9a evaporates in a wide range, it is possible to prevent the generation of noise due to partial bumping.
[0028]
Moreover, the side wall of the combustion chamber 5 through which the heat transfer tube of the auxiliary heat exchanger 8 passes is obtained by sandwiching the drain permeator 9a between the stepped portion 29 formed on the side wall of the combustion chamber 5 and the permeate body mounting plate 9b. The drain that is generated around the wall and hangs down through the side wall can be reliably received by the drain permeator 9a that is in contact with the side wall at the step portion 29 of the side wall. It does not hang down on the exchanger 7 or the burner 6.
[0029]
Further, by passing the coldest water in the water supply flow path to the auxiliary heat transfer pipe 8a, latent heat and sensible heat in the combustion gas can be efficiently recovered within a large temperature difference. Furthermore, since the cold water is preheated by the heating in the auxiliary heat transfer tube 8a, the generation of drain on the inner wall of the combustion chamber 5 wound around the winding tube 20 can be suppressed. And finally, since the hottest hot water can be passed through the main heat transfer pipe 7a in the water supply flow path, the generation of drain there can be effectively suppressed.
[0030]
Although the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, 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.
[0031]
【The invention's effect】
As described above in detail, according to the water heater according to claim 1 of the present invention, the drain generated in the auxiliary heat exchanger is evaporated by the drain evaporator. Since the sum treatment is unnecessary and most of the sensible heat in the combustion gas can be recovered, the thermal efficiency becomes very high. And since the combustion gas can be smoothly guided to the heat transfer tube of the auxiliary heat exchanger where the flow of the combustion gas is obstructed by the drain evaporator, the heat exchange there is promoted, and the thermal efficiency can be further improved. it can.
[0032]
Furthermore, according to the water heater according to claim 2 of the present invention, since the auxiliary heat exchanger and the rectifying plate can be implemented with a simple structure, the cost of manufacturing the water heater can be suppressed.
[0033]
Furthermore, according to the water heater according to claim 3 of the present invention, since the drain can be directly heated by the combustion gas, the drain can be favorably evaporated.
[0034]
Furthermore, according to the water heater according to claim 4 of the present invention, the exhaust resistance of the combustion gas can be reduced and the combustion of the burner can be maintained satisfactorily.
[0035]
Furthermore, according to the water heater according to claim 5 of the present invention, since the drain that flows down through the side wall of the combustion chamber can be reliably received by the drain permeator, the main heat exchanger and the burner are It can be prevented from being corroded.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a water heater according to an embodiment.
FIG. 2 is an external view of a water heater according to the present embodiment.
FIG. 3 is a view showing a water passage route of the water heater of the present embodiment.
FIG. 4 is a top view of the auxiliary heat exchange unit of the present embodiment.
FIG. 5 is a front view of the auxiliary heat exchange unit of the present embodiment.
FIG. 6 is a cross-sectional view of the auxiliary heat exchange unit of the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Water heater, 5 ... Combustion chamber, 6 ... Burner, 7 ... Main heat exchanger, 7a ... Main heat exchanger tube, 8 ... Sub heat exchanger, 8a ... Sub heat exchanger tube, 8aA ... Pre-sub heat exchanger tube, 8aB ... Rear auxiliary heat transfer tube, 9 ... drain evaporator, 9a ... drain permeator, 9b ... permeator mounting plate, 9c ... evaporation opening, 10 ... current plate, 10a ... vent, 29 ... step.

Claims

A burner that burns fuel in the combustion chamber;
A main heat exchanger provided above the burner for recovering sensible heat from the combustion gas of the burner and heating the water flow in the heat transfer tube;
Provided above the main heat exchanger, in addition to the sensible heat that could not be recovered by the main heat exchanger from the combustion gas that passed through the main heat exchanger, the latent heat was recovered and the water flow in the heat transfer tube A water heater with a secondary heat exchanger for heating
Provided above the main heat exchanger below the auxiliary heat exchanger, together with the receiving drain generated by the latent heat recovery in the secondary heat exchanger, and the main heat exchanger the drain is heated by the combustion gases A drain evaporator that evaporates in a path of the combustion gas formed between the auxiliary heat exchangers to give the drain an amount of heat necessary for vaporizing and evaporating the drain;
A water heater comprising: a rectifying plate that guides the combustion gas that has passed through the main heat exchanger flowing beside the drain evaporator toward the heat transfer tube of the sub heat exchanger.

In the sub heat exchanger, the heat transfer tubes are arranged in two rows at the front and rear,
2. The water heater according to claim 1, wherein the rectifying plate extends between the heat transfer tubes in parallel with the heat transfer tubes and has a substantially V-shaped cross section.

The drain evaporator includes a drain permeator made of a porous heat-resistant and nitric acid-resistant material and permeating the entire drain, and a permeator mounting plate for mounting the drain permeator, The water heater according to claim 1 or 2, wherein a plurality of openings are provided on the mounting surface of the penetrating body mounting plate.

The water heater according to any one of claims 1 to 3, wherein the rectifying plate is provided with a plurality of openings through which combustion gas passes.

A step is formed on a side wall of the combustion chamber, and the drain permeator is sandwiched between the step and the permeator mounting plate to prevent the drain permeator from coming off. Item 5. A water heater according to item 4.