JP3964313B2

JP3964313B2 - Heat exchange system

Info

Publication number: JP3964313B2
Application number: JP2002344321A
Authority: JP
Inventors: 洋志夏目; 松菊工藤
Original assignee: Fuji Jukogyo KK
Current assignee: Subaru Corp
Priority date: 2002-11-27
Filing date: 2002-11-27
Publication date: 2007-08-22
Anticipated expiration: 2022-11-27
Also published as: JP2004177011A

Description

【０００１】
【発明の属する技術分野】
本発明は熱交換システムに関し、特に被加温液を貯留する液体タンクに配設された熱交換器に加熱蒸気を供給して被加温液を加温する熱交換システムに関する。
【０００２】
【従来の技術】
例えば、ワークに切削等の機械加工を施す加工装置は、図４に加工装置の全体図を示すようにワークに機械加工を施す加工機Ｍ１、Ｍ２、Ｍ３、Ｍ４を有し、各加工機Ｍ１、Ｍ２、Ｍ３、Ｍ４において順次切削等の機械加工が施されたワークは、洗浄機Ｍ５により洗浄液による洗浄がなされて切粉や機械加工の際に付着したクーラント等が除去される。このワークの洗浄に使用される洗浄液は洗浄効果を向上させるため予め設定された温度に加温されている。
【０００３】
洗浄機Ｍ５に供給する洗浄液を加温する熱交換システムについて図５に示す回路図を参照して説明する。
【０００４】
符号１０１は洗浄液を貯留する液体タンクであり、液体タンク１０１内に貯留された洗浄液をポンプ１０２によって洗浄機Ｍ５に圧送供給し、洗浄機Ｍ５でワークの洗浄に使用された洗浄液は再び液体タンク１０１に回収されて循環して使用される。この循環使用される際に図示しない切粉受けによって洗浄液に混在する切粉等が除去される。
【０００５】
この液体タンク１０１には、蛇管状の熱交換器１０３が設けられ、液体タンク１０１に設けられた液温検知手段１０４の液温検知に基づいて開閉制御される蒸気制御弁１０６の開閉によりボイラー等の蒸気供給源１０７から熱交換機１０３に加熱蒸気を供給し、熱交換機１０３による熱交換によって液体タンク１０１内の被加温液体となる洗浄液を加温して洗浄効果の向上を図っている。
【０００６】
熱交換器１０３から排出される蒸気は、トラップ１０８によって凝縮液が分離される。トラップ１０８により分離された凝縮液の一部は液体タンク１０１に設けられた液位検知手段１０９による液位検知に基づいて開閉制御される凝縮液供給弁１１０の開閉により液体タンク１０１に供給され、液体タンク１０１内には常に所定量の洗浄液が保持される。また、凝縮液を供給しても液体タンク１０１内に所定量の洗浄液が確保できないときは、液位検知手段１０９の液位検知に従って開閉制御される工水制御弁１１１の開閉により給水源１１２から工業用水道水等の工水が供給され、液体タンク１０１内に所定量の洗浄液が保持される。
【０００７】
一方、液体タンク１０１に回収されることのない余剰の凝縮液は、一般に屋外の排水溝１１３等に排出される場合が多く、凝縮液の再利用が種々検討されている。
【０００８】
なお、廃液を減圧・低温濃縮槽に導入し、廃液・低温濃縮槽で回転する回転コイル、すなわち熱交換器に供給される加熱蒸気によって加温して濃縮液を得る廃液処理装置において、排出される蒸気が凝縮した後に、加工機に再利用することが提案されている（例えば、特許文献１参照）。
【０００９】
【特許文献１】
特開平８−２４３５４３号公報（段落番号００２６〜００２８、図１）
【００１０】
【発明が解決しようとする課題】
しかし、上記図４および図５に示す熱交換システムにおける液体タンク１０１内の洗浄液の温度調整は、液体タンク１０１内の洗浄液の液温を液温検知手段１０４により検知し、その液温検知に基づいて蒸気制御弁１０６を開閉制御して熱交換器１０３へ供給する加熱蒸気を調整することによって行われることから、蒸気制御弁１０６を閉じた際に熱交換器１０３内に残存する蒸気が凝縮して熱交換器１０３内の圧力が低下する。この圧力低下は、特に長期間にわたって蒸気制御弁１０６を閉じたときに顕著である。図６は熱交換器１０３内の圧力Ｐ１と液体タンク１０１内における熱交換器１０３が位置する洗浄液の液圧Ｐ０との相対関係を示す説明図であり、蒸気制御弁１０６が閉じられると、蒸気の凝縮により熱交換器１０３内の圧力Ｐ１が低下を始め、次第に低下して洗浄液の液圧Ｐ０を越えてハッチングで示すように洗浄液の温度に相当する蒸気飽和圧力まで低下する。
【００１１】
ここで、熱交換器１０３に腐食等によるピンホール等の損傷があると、熱交換器１０３内の圧力Ｐ１と洗浄液の液圧Ｐ０の差圧により損傷部から熱交換器１０３内に液体タンク１０１内の洗浄液が浸入するおそれがある。この洗浄液内にはワークの洗浄に伴う不純物が混在して汚染されていることが多い。また、洗浄液として炭化水素や石油系の洗浄液を使用する場合があり、洗浄液が混入した凝縮液が屋外の排水溝１１３等に排出されると環境汚染等の原因となることが懸念される。また、この汚染された凝縮液を加工機等の工水として再利用すると種々の影響を及ぼすことが懸念される。
【００１２】
また、特許文献１にあっても同様にコイル内に汚染物質が浸入することが懸念され、凝縮液の利用に影響を及ぼすおそれがある。
【００１３】
従って、かかる点に鑑みなされた本発明の目的は、液体タンクに配設された熱交換器に加熱蒸気を供給して被加温液を加温するにあたり、熱交換器から排出される凝縮液に被加温液が混入するおそれのない熱交換システムを提供することにある。
【００１４】
【課題を解決するための手段】
上記目的を達成するため、請求項1記載の発明は、被加温液を貯留する液体タンクに配設された熱交換器に加熱蒸気を供給して熱交換により上記被加温液を加温する熱交換システムにおいて、上記被加温液を貯留する液体タンクと、該液体タンクに配設された熱交換器と、該熱交換器の上流側に接続されて加熱蒸気を上記熱交換器に供給する蒸気供給手段と、上記熱交換器の下流側に接続されて開閉により上記蒸気供給手段から上記熱交換器内へ供給される加熱蒸気を制御する蒸気制御弁と、上記液体タンクより上方位置おいて補給液を貯留する補給液タンクと、該補給液タンクの底部に開口する補給口と上記熱交換器の上流側との間を連通する補給路と、該補給路に介在し、かつ上記蒸気供給手段からの加熱蒸気の供給停止により上記熱交換器内の圧力が低下したときに開いて上記補給液タンク内の補給液を上記熱交換器内に流入させる補給液制御弁とを備えたことを特徴とする。
【００１５】
請求項１の発明によると、液体タンク内の被加温液を加温する加温時には、熱交換器の下流側に接続された蒸気制御弁を開き蒸気供給手段により熱交換器に加熱蒸気を供給することから、その蒸気圧によって熱交換器内が加圧状態に維持される。また蒸気制御弁を閉じた際にも蒸気供給手段からの加熱蒸気によって熱交換器内が加圧状態に維持され、常に熱交換器内の圧力が液体タンク内の被加熱液の液圧より大きく維持される。よって、仮に熱交換器に腐食等によるピンホール等の損傷が発生した場合でも、液体タンク内に貯留された被加温液が損傷部を介して熱交換器内に浸入することが防止され、熱交換器により発生した凝縮液に被加温液が混入することはない。従って、被加温液の混入のない清浄な凝縮液の利用が可能になり、凝縮液の有効活用が得られる。また、凝縮液を排水溝等に排出した場合でも環境への影響が回避できる。また、液体タンクより上方に補給液を貯留する補給液タンクを設け、補給液タンクの底部に開口する補給口と熱交換器の上流側との間を連通する補給路に熱交換器内の圧力が低下したときに開いて補給液タンク内の補給液を熱交換器内に流入させる補給液制御弁を介在させることから、例えば稼働停止の際において蒸気供給手段から熱交換器への蒸気の供給を停止し、かつ蒸気制御弁閉じることによって、次第に熱交換器内に残存する蒸気が凝縮して熱交換器内の圧力が低下すると補給液制御弁が開き、補給液タンク内に貯留された補給液が熱交換器内に流入して熱交換器内が液体タンク内の被加温液の液圧よりも大きな圧力に保持される。よって、仮に熱交換器に腐食等によるピンホール等の損傷が発生した場合でも液体タンク内に貯留された被加温液が損傷部を介して熱交換器内に浸入することがなく、凝縮液に被加温液が混入することがない。
【００２０】
請求項２に記載の発明は、請求項１の熱交換システムにおいて、上記補給液タンクは、該補給液タンク内に貯留された補給液の液位を表示する液位表示手段を有することを特徴とする。
【００２１】
請求項２の発明によると、請求項１の発明において補給液タンク内に貯留された補給液が熱交換器内に流入して熱交換器内が液体タンク内の被加温液の液圧より大きな圧力に保持したとき、仮に熱交換器にピンホール等の損傷があると損傷部から補給液が液体タンク側に流出して補給液タンク内の液位が下降する。この液位の下降を液位表示手段で確認することによって熱交換器の損傷発生を知ることができる。
【００２２】
請求項３に記載の発明は、請求項１または２の熱交換システムにおいて、上記補給液は、上記熱交換器から排出された凝縮液であって、上記蒸気制御弁と補給液タンクとの間に配置され、開閉によって上記熱交換器側から上記補給液タンクへの凝縮液の供給を制御する凝縮液供給弁を有し、上記補給液タンクは、オーバフローにより該補給液タンクに貯留される凝縮液の貯留上限位置を規制すると共に上記液体タンクに凝縮液を供給する排出口を有することを特徴とする。
【００２３】
請求項３の発明によると、熱交換器で発生した凝縮液を請求項１または２における熱交換器内の圧力が低下した際に熱交換器内に供給する補給液として、また液体タンク内の被加温液として有効活用できると共に、補給液タンク内に所定量の凝縮液を確保することができる。
【００２４】
請求項４に記載の発明は、請求項３の熱交換システムにおいて、上記液体タンク内の被加温液の液位を検知する液位検知手段を有し、該液位検知手段の液位検知に基づいて上記凝縮液供給弁を開閉制御することを特徴とする。
【００２５】
請求項４の発明によると、液体タンク内の被加温液の液位検出に基づいて凝縮液供給弁を開閉して凝縮液を液体タンク内に供給することによって、液体タンク内の被加温液の液位を調整することができる。
【００２６】
【発明の実施の形態】
次に本発明の熱交換システムの実施の形態を洗浄に使用される洗浄液を加温する場合を例に図１乃至図３を参照して説明する。
【００２７】
図１は熱交換システムの概要を示す回路図であって、符号１は液体タンクであり、液体タンク１内に貯留された被加温液である洗浄液をポンプ２によって洗浄機３に圧送供給し、洗浄機３でワークの洗浄に使用された洗浄液は再び液体タンク１に回収されて循環して使用される。
【００２８】
この液体タンク１には蛇管状の熱交換器１１が設けられている。熱交換器１１の上流側１１ａは、蒸気供給手段である蒸気供給路１２を介してボイラー等の蒸気供給源１３に接続され、蒸気供給路１２にストップ弁１４が介在されている。熱交換器１１の下流側１１ｂには、液温検知手段５による液体タンク１内の洗浄液の液温検知に基づいて開閉制御される蒸気制御弁１６および凝縮液を分離するトラップ１７が順に介在する通路１５が接続され、トラップ１７と並列にストップ弁１８が配置されている。トラップ１７の凝縮液排出側は逆止弁２０が介在する凝縮液回収路１９を介して例えば屋外の排水溝２１に導かれている。
【００２９】
また、熱交換器１１の上流側１１ａ側は蒸気供給路１２から分岐すると共に補給液制御弁である逆止弁２２が介在する補給路２３を介して液体タンク１の上方位置に配置された補給液タンク３１の補給口３６に接続されている。
【００３０】
凝縮液回収路１９の逆止弁２０の下流側と補給路２３の逆止弁２２と補給液タンク３１との間とは凝縮液供給路２４によって連結されている。凝縮液供給路２４にはストップ弁２５と、液体タンク１に設けられた液位検知手段６による洗浄液の液位検知に基づいて開閉制御される凝縮液供給弁２６が介装されている。更に凝縮液供給路２４の凝縮液供給弁２６より下流側に、ストップ弁２８および液位検知手段６の液位検知に従って開閉制御される工水制御弁２９を介在して工業用水道等の給水源３０に接続される工水供給路２７が接続されている。
【００３１】
補給液タンク３１は、底部３２に上記補給路２３が接続される補給口３６が開口し、周壁３３の上部位置に排出口３４が開口し、この排出口３４から補給液タンク３１に貯留される補給液である凝縮液をオーバフローさせることによって貯留上限位置Ｌ１に規制して所定量の凝縮液を確保する。さらに、周壁３３に液位表示手段３５が設けられている。液位表示手段３５は、補給液タンク３１内に貯留される凝縮液の液位が外部から目視確認できるように、側壁３３に開口する開口部３５ａと、この開口部３５ａを遮蔽するガラス等の透明板３５ｂとによる簡単な構成で形成される。
【００３２】
次に、このように構成された本実施の形態の熱交換システムの作動について説明する。
【００３３】
通常の稼働時には、ストップ弁１４、２５、２８が開かれ、液温検知手段５による液体タンク１内の洗浄液の液温検知に基づいて制御される蒸気制御弁１６の開閉により、蒸気供給源１３から蒸気供給路１２を介して熱交換器１１に供給される加熱蒸気が調整されて液体タンク１内の洗浄液が所定の温度に維持される。
【００３４】
すなわち、洗浄液の温度が予め設定された温度より低いときには液温検知手段５による検知温度に基づいて蒸気制御弁１６が開き、蒸気供給源１３から蒸気供給路１２を介して熱交換器１１に加熱蒸気を供給して熱交換器１１による熱交換によって液体タンク１内の洗浄液が加温される。一方、洗浄液の温度が予め設定された温度に加温され、あるいは洗浄液の温度がそれより高いときには、液温検知手段５による検知温度に基づいて蒸気制御弁１６が閉じられ、蒸気供給源１３から熱交換器１１への加熱蒸気の供給が停止されて熱交換器１１による液体タンク１内の洗浄液の加温を中断することによって液体タンク１内の洗浄液が所定の温度に維持される。この最適な温度に調整された洗浄液がポンプ２によって洗浄機３に供給されて、効率的なワークの洗浄が行われる。
【００３５】
この蒸気制御弁１６を開き蒸気供給源１３から熱交換器１１に加熱蒸気を供給する加温時には、その供給される加熱蒸気の蒸気圧によって逆止弁２２が閉じられ、かつ蒸気供給路１２、熱交換器１１、通路１５内が加圧状態に、また蒸気制御弁１６を閉じた際にも蒸気供給源１３からの加熱蒸気の蒸気圧によって蒸気供給路１２および熱交換器１１、通路１５内が加圧状態なり、蒸気供給路１２、熱交換器１１および通路１５内の圧力Ｐ１は常に液体タンク１内に貯留された洗浄液の液圧Ｐ０より大きく維持される（Ｐ１＞Ｐ０）。図２は、熱交換器１１内の圧力Ｐ１と液体タンク１内の熱交換器１１と対応する部分における洗浄液の液圧Ｐ０の関係を示す説明図である。
【００３６】
熱交換器１１において洗浄液の加温に使用されて凝縮水（凝縮液）を含む蒸気は、蒸気制御弁１６の開に伴って通路１５を経てトラップ１７に送られ、トラップ１７によって凝縮液が分離される。トラップ１７によって分離された凝縮液は凝縮液回収路１９に送られ、排水溝２１に排出される。
【００３７】
ここで、連続するワークの洗浄によって液体タンク１内に貯留された洗浄液が次第に減少し、液位検知手段６が予め設定された洗浄液の下限液位を検知すると、その検知に基づいて凝縮液供給路２４に設けられた凝縮液供給弁２６が開かれ、凝縮液回収路１９側からの凝縮液が凝縮液供給路２４および補給路２３を経て補給口３６から補給液タンク３１内に供給される。補給液タンク３１内に供給された凝縮液は、排出口３４からオーバフローして液体タンク１内に洗浄液として供給され、かつ補給液タンク３１内の凝縮液の液面は貯留上限位置Ｌ１に保持される。
【００３８】
この供給によって洗浄液が増量されて、液体タンク１１内の凝縮液の液面が上昇して液位検知手段６が予め設定された上限液位を検知すると、凝縮液供給弁２６が閉じ補給液タンク３１の排出口３４からのオーバフローによる供給を停止することによって液体タンク１内に常に所定量の洗浄液が保持される。また、補給液タンク３１内の凝縮液は、その液面が貯留上限位置Ｌ１となる所定量貯留される。
【００３９】
一方、液位検知手段６が下限液位を検知し、凝縮液供給弁２６が開いても液体タンク１に十分な量の凝縮液が供給されないときには、凝縮液供給弁２６を閉じて後述する工水制御弁２９の開弁により給水源３０からの工水の排出溝２１側への逆流を防止すると共に工水制御弁２９を開き、凝縮液に代えて給水源３０から工水を工水供給路２７、凝縮液供給路２４、補給路２３を介して補給口３６から補給液タンク３１内に供給する。補給液タンク３１内に供給された工水は、排出口３４からオーバフローして液体タンク１内に洗浄液として供給される。この供給によって洗浄液が増量されて、液位検知手段６が上限液位を検知すると工水制御弁２９が閉じて補給液タンク３１から液体タンク１への供給を停止することによって、液体タンク１内に常に所定量の洗浄液が保持される。
【００４０】
従って、通常稼働において、液体タンク１内の洗浄液が所定量まで減少すると、洗浄液の加温に使用された蒸気の凝縮液あるいは工水によって補給されて円滑な洗浄作業が確保できる。また、熱交換器１１から排出される凝縮液が有効的に再利用できると共に工水の使用量を削減することができる。特に工水に対して凝縮液を優先して使用することによりより効率的に凝縮液の活用が得られ、工水の使用量の削減および凝縮液の排水溝２１等への排出量の削減が得られる。
【００４１】
長期にわたる稼働停止の際には、各ストップ弁１４、１８、２５、２８を閉じるとと共に、通路１５に設けられた蒸気制御弁１６、凝縮液供給路２４に設けられた凝縮液供給弁２６、工水供給路２７の工水制御弁２９を閉じる。
【００４２】
このように加熱蒸気を熱交換器１１に供給する蒸気供給路１２に設けられたストップ弁１４を閉じ、かつ熱交換器１１の下流側の通路１５に設けられた蒸気制御弁１６を閉じると次第に熱交換器１１内に残存する蒸気が凝縮し、熱交換器１１内の圧力Ｐ１が低下し始める。
【００４３】
図３は熱交換器１１内の圧力Ｐ１と液体タンク１内の洗浄液の液圧Ｐ０の相対関係を示す説明図であり、ストップ弁１４および蒸気制御弁１６を閉じると、熱交換器１１および蒸気供給路１２、通路１５内の蒸気が凝縮を開始する。この蒸気の凝縮により熱交換器１１および蒸気供給路１２、通路１５内の圧力Ｐ１が次第に低下する。熱交換器１１および蒸気供給路１２、通路１５内の圧力Ｐ１が補給液タンク３１内に貯留された凝縮液により逆止弁２２に作用する液圧Ｐ２まで低下し、より厳密には液圧Ｐ２より若干低下すると、逆止弁２２がその液圧Ｐ２と熱交換器１１および蒸気供給路１２、通路１５内の圧力Ｐ１との差圧により開き、開いた逆止弁２２を介して補給液タンク３１に貯留された凝縮液が蒸気供給路１２から熱交換器１１および通路１５内に流入し、凝縮液によって満たされ熱交換器１１内の圧力Ｐ１が液圧Ｐ２に保持される。この液圧Ｐ２は、液体タンク１より補給液タンク３１が上方に配置されることからこのヘッド差ｈにより液体タンク１内の洗浄液の液圧Ｐ０より常に大きく設定される（Ｐ２＞Ｐ０）。
【００４４】
この通路１５、熱交換器１１、蒸気供給路１２内への凝縮液の流入により補給液タンク３１内の凝縮液の液面は、貯留上限位置Ｌ１から基準液面位置Ｌ２まで低下する。
【００４５】
また、稼働再開時には、各ストップ弁１４、２５、２８を開き、液体タンク１内の洗浄液を加温するために蒸気制御弁１６を開くと、蒸気供給源１３からの加熱蒸気が蒸気供給路１２を介して熱交換器１１に供給される。この加熱蒸気の蒸気圧によって蒸気供給路１２、熱交換器１１、通路１５内に保持された凝縮液はトラップ１６から凝縮液回収路１９に送り出され、上記同様に通常の稼働が行われる。
【００４６】
このように構成された熱交換システムによると、通常の稼働時において、液体タンク１内の洗浄液を加温する加温時には、蒸気制御弁１６を開き蒸気供給源１３から熱交換器１１に加熱蒸気を供給する蒸気圧によって逆止弁２２が閉じられ、かつ蒸気供給路１２、熱交換器１１、通路１５内が加圧状態に、また蒸気制御弁１６を閉じた際にも蒸気供給源１３からの加熱蒸気によって加圧されて熱交換器１１内が加圧状態に維持され、熱交換器１１内の圧力Ｐ１は常に液体タンク１内の洗浄液の液圧Ｐ０より大きく維持される（Ｐ１＞Ｐ０）。
【００４７】
従って、稼働中は常に熱交換器１１内の圧力Ｐ１が液体タンク１内の洗浄液の液圧Ｐ０より大きく維持されることから、仮に熱交換器１１に腐食等によるピンホール等の損傷が発生した場合でも、液体タンク１内に貯留された洗浄液が損傷部を介して熱交換器１１内に浸入することが防止され、熱交換器１１により発生した凝縮液が洗浄液によって汚染されることがない。。
【００４８】
従って、熱交換器１１から排出された清浄な凝縮液を液体タンク１に供給して洗浄液として再利用することができ、また他の加工機等の工水として使用することができて凝縮液の有効活用が得られる。さらに、余剰の凝縮液を例えば屋外の排水溝２１に排出した場合にも環境への影響が回避できる。
【００４９】
一方、稼働停止の際において、蒸気供給路１２に設けられたストップ弁１４を閉じて熱交換器１１への蒸気の供給を停止し、かつ熱交換器１１の下流側の回路１５に設けられた蒸気制御弁１６を閉じると、次第に熱交換器１１内に残存する蒸気が凝縮して熱交換器１１内の圧力Ｐ１が低下するが、補給液タンク３１内に貯留された凝縮液により逆止弁２２に作用する液圧Ｐ２まで低下すると逆止弁２２が開き、補給液タンク３１に貯留された凝縮液が熱交換器１１内に流入して熱交換器１１内が液体タンク１内の洗浄液の液圧Ｐ０より大きな圧力Ｐ２に保持される。
【００５０】
従って、熱交換器１１内が液体タンク１内の洗浄液の液圧Ｐ０より大きな圧力Ｐ２に維持されることから、仮に熱交換器１１に腐食等によるピンホール等の損傷が発生した場合でも液体タンク１内に貯留された洗浄液が損傷部を介して熱交換器１１内に浸入することが防止され、熱交換器１１内が洗浄液によって汚染されることがなく、洗浄液として再利用することができる。また他の加工機等の工水として使用することができて凝縮液の有効活用が得られる。さらに、余剰の凝縮液を例えば屋外の排水溝２１に排出した場合にも環境への影響が回避できる。
【００５１】
また、熱交換器１１にピンホール等の損傷の発生がある場合には、稼働停止の状態において、熱交換器１１内に充填された凝縮液が熱交換器１１内の圧力Ｐ２と液体タンク１内の洗浄液の液圧Ｐ０の差圧により熱交換器１１内の凝縮液が損傷部から液体タンク１の洗浄液側に流出して補給液タンク３１内の凝縮液の液面が基準液面Ｌ２より次第に下降する。この基準液面Ｌ２からの液面下降を目視確認することによって熱交換器１１の損傷の発生を知ることができる。
【００５２】
さらに、従来熱交換システムにおいて熱交換器の上流側に配設されていた蒸気制御弁を熱交換器１１の下流側に配置する等、従来の熱交換システムを大きく変更することなく構成することができ、設備コストの増大を招くことなく既存の熱交換システムに適用することもできる。
【００５３】
なお、本発明は上記実施の形態に限定されることなく、発明の趣旨を逸脱しない範囲で種々変更可能である。例えば、上記実施の形態では補給液タンク３１の液位表示手段３５として液面を外部から目視確認できるように周壁３３に形成した開口部３５ａを透明板３５ｂにより遮蔽することによって形成したが、液面を検知するフロート等により形成することもできる。また、上記実施の形態では洗浄液を加温する場合を例に説明したが、液体タンクに貯留された他の被加温液を液体タンクに配設された熱交換器に加熱蒸気を供給して加温する他の熱交換システムに広く適用することもできる。
【００５４】
【発明の効果】
以上説明した本発明の熱交換システムによると、熱交換器の上流側に接続されて加熱蒸気を熱交換器に供給する蒸気供給手段と、熱交換器の下流側に接続されて開閉により蒸気供給手段から熱交換器内へ供給される加熱蒸気を制御する蒸気制御弁とを備えることによって、常に蒸気供給手段からの加熱蒸気によって熱交換器内が加圧状態に維持されて常に熱交換器内の圧力が液体タンク内の被加熱液の液圧より大きく維持される。よって、仮に熱交換器に腐食等によるピンホール等の損傷が発生した場合でも、液体タンク内に貯留された被加温液が損傷部を介して熱交換器内に浸入することが防止され、熱交換器により発生した凝縮液に被加温液が混入することがない。
【００５５】
さらに、液体タンクより上方位置に補給液を貯留する補給液タンクを配置し、補給液タンクと熱交換器の上流側との間を連通する補給路に、蒸気供給手段からの加熱蒸気供給停止により上記熱交換器内の圧力が低下したときに開き上記補給液タンク内の補給液を上記熱交換器内に流入させる補給液制御弁を設けることによって、例えば稼働停止の際において熱交換器内の圧力が低下すると補給液制御弁が開き、補給液タンク内に貯留された補給液が熱交換器内に流入して熱交換器内が液体タンク内の洗浄液の液圧より大きな圧力に保持される。よって、仮に熱交換器に腐食等によるピンホール等の損傷が発生した場合でも液体タンク内に貯留された被加温液が損傷部を介して熱交換器内に浸入することが防止される。
【図面の簡単な説明】
【図１】本発明による熱交換システムの実施の形態を示す回路図である。
【図２】稼働時における熱交換器内の圧力と液体タンク内の洗浄液の液圧の関係を示す説明図である。
【図３】稼働停止時における熱交換器内の圧力と液体タンク内の洗浄液の液圧の関係を示す説明図である。
【図４】従来の熱交換システムを備えた加工装置の概要を示す全体図である。
【図５】従来の熱交換システムの概要を示す回路図である。
【図６】稼働停止時における熱交換器内の圧力と液体タンク内の洗浄液の圧力の相対関係を示す説明図である。
【符号の説明】
１液体タンク
２ポンプ
５液温検知手段
６液位検知手段
１１熱交換器
１１ａ上流側
１１ｂ下流側
１２蒸気供給路（蒸気供給手段）
１３蒸気供給源
１４ストップ弁
１５通路
１６蒸気制御弁
１７トラップ
１９凝縮液回収路
２０逆止弁
２２逆止弁（補給液制御弁）
２３補給路
２４凝縮液供給路
２６凝縮液供給弁
３１補給液タンク
３２底部
３４排出口
３５液位表示手段
３６補給口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat exchange system, and more particularly to a heat exchange system for heating heated liquid by supplying heated steam to a heat exchanger disposed in a liquid tank that stores the heated liquid.
[0002]
[Prior art]
For example, a processing apparatus that performs machining such as cutting on a workpiece includes processing machines M1, M2, M3, and M4 that perform machining on the workpiece as shown in FIG. 4 as an overall view of the processing apparatus. , M2, M3, and M4 are sequentially subjected to machining such as cutting, and the workpiece is washed with a washing solution by a washing machine M5 to remove chips and coolant adhering during machining. The cleaning liquid used for cleaning the workpiece is heated to a preset temperature in order to improve the cleaning effect.
[0003]
A heat exchange system for heating the cleaning liquid supplied to the cleaning machine M5 will be described with reference to a circuit diagram shown in FIG.
[0004]
Reference numeral 101 denotes a liquid tank for storing the cleaning liquid. The cleaning liquid stored in the liquid tank 101 is pumped and supplied to the cleaning machine M5 by the pump 102, and the cleaning liquid used for cleaning the workpiece by the cleaning machine M5 is again the liquid tank 101. It is recovered and used in circulation. When this circulating use is performed, chips and the like mixed in the cleaning liquid are removed by a chip receiver (not shown).
[0005]
The liquid tank 101 is provided with a serpentine heat exchanger 103, and a boiler or the like is provided by opening and closing a steam control valve 106 that is controlled to open and close based on the liquid temperature detection of the liquid temperature detecting means 104 provided in the liquid tank 101. The heating steam is supplied from the steam supply source 107 to the heat exchanger 103, and the cleaning liquid that becomes the heated liquid in the liquid tank 101 is heated by heat exchange by the heat exchanger 103 to improve the cleaning effect.
[0006]
The vapor discharged from the heat exchanger 103 is separated from the condensate by the trap 108. A portion of the condensate separated by the trap 108 is supplied to the liquid tank 101 by opening and closing a condensate supply valve 110 that is controlled to open and close based on the liquid level detection by the liquid level detection means 109 provided in the liquid tank 101. A predetermined amount of cleaning liquid is always held in the liquid tank 101. Further, when a predetermined amount of cleaning liquid cannot be secured in the liquid tank 101 even if condensate is supplied, the water supply source 112 is opened and closed by opening and closing the construction water control valve 111 that is controlled to open and close according to the liquid level detection of the liquid level detection means 109. Industrial water such as industrial tap water is supplied, and a predetermined amount of cleaning liquid is held in the liquid tank 101.
[0007]
On the other hand, surplus condensate that is not collected in the liquid tank 101 is generally discharged to an outdoor drainage groove 113 or the like in many cases, and various reuses of condensate have been studied.
[0008]
In addition, the waste liquid is introduced into the decompression / low temperature concentration tank and discharged in a waste coil treatment device that obtains the concentrate by heating with a rotating coil rotating in the waste liquid / low temperature concentration tank, that is, heating steam supplied to the heat exchanger. It has been proposed that after the steam is condensed, it is reused in the processing machine (for example, see Patent Document 1).
[0009]
[Patent Document 1]
JP-A-8-243543 (paragraph numbers 0026 to 0028, FIG. 1)
[0010]
[Problems to be solved by the invention]
However, the temperature adjustment of the cleaning liquid in the liquid tank 101 in the heat exchange system shown in FIGS. 4 and 5 is based on the detection of the liquid temperature by detecting the liquid temperature of the cleaning liquid in the liquid tank 101 by the liquid temperature detecting means 104. Therefore, the steam remaining in the heat exchanger 103 is condensed when the steam control valve 106 is closed because the heating steam supplied to the heat exchanger 103 is adjusted by controlling the opening and closing of the steam control valve 106. As a result, the pressure in the heat exchanger 103 decreases. This pressure drop is particularly noticeable when the steam control valve 106 is closed for a long period of time. FIG. 6 is an explanatory diagram showing the relative relationship between the pressure P1 in the heat exchanger 103 and the liquid pressure P0 of the cleaning liquid in which the heat exchanger 103 is located in the liquid tank 101. When the steam control valve 106 is closed, As a result of the condensation, the pressure P1 in the heat exchanger 103 starts to decrease, gradually decreases, exceeds the cleaning liquid pressure P0, and decreases to a steam saturation pressure corresponding to the temperature of the cleaning liquid as shown by hatching.
[0011]
Here, if the heat exchanger 103 is damaged due to pinholes or the like due to corrosion or the like, the liquid tank 101 enters the heat exchanger 103 from the damaged portion due to the differential pressure between the pressure P1 in the heat exchanger 103 and the liquid pressure P0 of the cleaning liquid. There is a risk that the cleaning liquid invades. In many cases, the cleaning liquid is contaminated with impurities accompanying the cleaning of the workpiece. In addition, hydrocarbons or petroleum-based cleaning liquids may be used as the cleaning liquid, and there is a concern that condensate mixed with the cleaning liquid may cause environmental pollution or the like when discharged to the outdoor drainage groove 113 or the like. Moreover, there are concerns that various effects will be caused if this contaminated condensate is reused as industrial water for a processing machine or the like.
[0012]
Moreover, even if it exists in patent document 1, there exists a possibility that a contaminant may penetrate | invade in a coil similarly, and there exists a possibility of affecting the utilization of a condensate.
[0013]
Accordingly, an object of the present invention made in view of such a point is to provide a condensate discharged from a heat exchanger when heating steam is supplied to a heat exchanger disposed in a liquid tank to heat the liquid to be heated. An object of the present invention is to provide a heat exchanging system that does not cause a mixture of a liquid to be heated.
[0014]
[Means for Solving the Problems]
  Achieve the above objectiveFor,Claim 1DescribedThe present invention provides a heat exchange system in which heating steam is supplied to a heat exchanger disposed in a liquid tank that stores a liquid to be heated and the liquid to be heated is heated to exchange the liquid to be heated. A liquid tank to be stored; a heat exchanger disposed in the liquid tank; steam supply means connected to the upstream side of the heat exchanger to supply heating steam to the heat exchanger; and A steam control valve which is connected to the downstream side and controls heating steam supplied from the steam supply means into the heat exchanger by opening and closing;A replenisher tank that stores replenisher at a position above the liquid tank; a replenishment passage that communicates between a replenishment port that opens at the bottom of the replenisher tank and the upstream side of the heat exchanger; and the replenisher Replenishment that opens when the pressure in the heat exchanger decreases due to the supply stop of the heating steam from the steam supply means and flows the replenisher in the replenisher tank into the heat exchanger. With liquid control valveIt is provided with.
[0015]
  According to the first aspect of the invention, when heating the liquid to be heated in the liquid tank, the steam control valve connected to the downstream side of the heat exchanger is opened and the steam is supplied to the heat exchanger by the steam supply means. Since being supplied, the inside of the heat exchanger is maintained in a pressurized state by the vapor pressure. Even when the steam control valve is closed, the heat exchanger is maintained in a pressurized state by the heating steam from the steam supply means, and the pressure in the heat exchanger is always higher than the liquid pressure of the liquid to be heated in the liquid tank. Maintained. Therefore, even if damage such as pinholes due to corrosion or the like occurs in the heat exchanger, the heated liquid stored in the liquid tank is prevented from entering the heat exchanger through the damaged portion, The liquid to be heated is not mixed into the condensate generated by the heat exchanger. Therefore, it becomes possible to use a clean condensate free from the mixture of the liquid to be heated, and an effective use of the condensate can be obtained. In addition, even when the condensate is discharged to a drainage groove or the like, environmental influences can be avoided.In addition, a replenisher tank that stores replenisher liquid above the liquid tank is provided, and the pressure in the heat exchanger is connected to a replenishment path that communicates between a replenishment port that opens at the bottom of the replenisher liquid tank and the upstream side of the heat exchanger. Supply of steam from the steam supply means to the heat exchanger when the operation is stopped, for example, when an operation is stopped. When the steam control valve is closed and the steam control valve is closed, the steam remaining in the heat exchanger gradually condenses and the pressure in the heat exchanger decreases, so that the replenisher control valve opens and the replenishment stored in the replenisher tank The liquid flows into the heat exchanger, and the inside of the heat exchanger is maintained at a pressure larger than the liquid pressure of the liquid to be heated in the liquid tank. Therefore, even if a pinhole or the like is damaged due to corrosion or the like in the heat exchanger, the liquid to be heated stored in the liquid tank does not enter the heat exchanger through the damaged portion, and the condensed liquid The heated liquid will not be mixed in.
[0020]
  Claim2The invention described in claim 11In this heat exchange system, the replenisher tank has a liquid level display means for displaying the liquid level of the replenisher liquid stored in the replenisher liquid tank.
[0021]
  Claim2According to the invention, the claims1In the present invention, when the replenisher stored in the replenisher tank flows into the heat exchanger and the heat exchanger is maintained at a pressure higher than the liquid pressure of the liquid to be heated in the liquid tank, the heat exchanger is temporarily If there is damage such as a pinhole, the replenishment liquid flows out from the damaged part to the liquid tank side, and the liquid level in the replenishment liquid tank is lowered. The occurrence of damage to the heat exchanger can be known by confirming the lowering of the liquid level with the liquid level display means.
[0022]
  Claim3The invention described in claim 11Or2In the heat exchange system, the replenisher is condensate discharged from the heat exchanger, and is disposed between the steam control valve and a replenisher tank, and is replenished from the heat exchanger side by opening and closing. A condensate supply valve for controlling the supply of condensate to the liquid tank, and the replenisher tank regulates a storage upper limit position of the condensate stored in the replenisher tank due to overflow and is condensed to the liquid tank. It has the discharge port which supplies a liquid, It is characterized by the above-mentioned.
[0023]
  Claim3According to the invention, the condensate generated in the heat exchanger is claimed.1Or2As a replenisher that is supplied to the heat exchanger when the pressure in the heat exchanger decreases, and as a warmed liquid in the liquid tank, a predetermined amount of condensate is secured in the replenisher tank. can do.
[0024]
  Claim4The invention described in claim 13In the heat exchange system, the liquid level detection means for detecting the liquid level of the liquid to be heated in the liquid tank is provided, and the condensate supply valve is controlled to open and close based on the liquid level detection of the liquid level detection means. It is characterized by that.
[0025]
  Claim4According to the invention, the liquid of the heated liquid in the liquid tank is supplied by opening and closing the condensate supply valve based on the liquid level detection of the heated liquid in the liquid tank and supplying the condensed liquid into the liquid tank. The position can be adjusted.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the heat exchange system of the present invention will be described with reference to FIGS. 1 to 3 by taking as an example the case of heating a cleaning liquid used for cleaning.
[0027]
FIG. 1 is a circuit diagram showing an outline of a heat exchange system. Reference numeral 1 denotes a liquid tank, and a cleaning liquid which is a warmed liquid stored in the liquid tank 1 is pumped and supplied to a cleaning machine 3 by a pump 2. The cleaning liquid used for cleaning the workpiece in the cleaning machine 3 is again collected in the liquid tank 1 and circulated for use.
[0028]
The liquid tank 1 is provided with a serpentine heat exchanger 11. The upstream side 11 a of the heat exchanger 11 is connected to a steam supply source 13 such as a boiler via a steam supply path 12 that is a steam supply means, and a stop valve 14 is interposed in the steam supply path 12. On the downstream side 11b of the heat exchanger 11, a steam control valve 16 that is controlled to open and close based on detection of the liquid temperature of the cleaning liquid in the liquid tank 1 by the liquid temperature detection means 5 and a trap 17 that separates the condensate are sequentially interposed. A passage 15 is connected, and a stop valve 18 is arranged in parallel with the trap 17. The condensate discharge side of the trap 17 is led to, for example, an outdoor drainage groove 21 via a condensate recovery path 19 in which a check valve 20 is interposed.
[0029]
In addition, the upstream side 11a side of the heat exchanger 11 branches from the steam supply path 12 and is replenished disposed above the liquid tank 1 via a replenishment path 23 with a check valve 22 serving as a replenisher control valve. The liquid tank 31 is connected to the supply port 36.
[0030]
The downstream side of the check valve 20 in the condensate recovery path 19 and the check valve 22 in the supply path 23 and the supply liquid tank 31 are connected by a condensate supply path 24. The condensate supply path 24 is provided with a stop valve 25 and a condensate supply valve 26 that is controlled to open and close based on detection of the cleaning liquid level by the liquid level detection means 6 provided in the liquid tank 1. Further, downstream of the condensate supply passage 26 in the condensate supply path 24, an industrial water control valve 29 that is controlled to open and close in accordance with the liquid level detection of the stop valve 28 and the liquid level detection means 6 is interposed to supply industrial water supply or the like. The industrial water supply path 27 connected to the water source 30 is connected.
[0031]
In the replenishing liquid tank 31, a replenishing port 36 to which the replenishing path 23 is connected to the bottom 32 is opened, and a discharge port 34 is opened at an upper position of the peripheral wall 33, and the replenishing liquid tank 31 is stored in the replenishing liquid tank 31. By condensing the condensate that is the replenisher, a predetermined amount of condensate is secured by restricting to the storage upper limit position L1. Further, a liquid level display means 35 is provided on the peripheral wall 33. The liquid level display means 35 has an opening 35a that opens to the side wall 33 and glass or the like that shields the opening 35a so that the liquid level of the condensate stored in the replenishing liquid tank 31 can be visually confirmed from the outside. It is formed with a simple configuration by the transparent plate 35b.
[0032]
Next, the operation of the heat exchange system of the present embodiment configured as described above will be described.
[0033]
During normal operation, the stop valves 14, 25, and 28 are opened, and the steam supply source 13 is opened and closed by opening and closing the steam control valve 16 that is controlled based on the liquid temperature detection means 5 detecting the liquid temperature of the cleaning liquid in the liquid tank 1. Then, the heating steam supplied to the heat exchanger 11 through the steam supply path 12 is adjusted, and the cleaning liquid in the liquid tank 1 is maintained at a predetermined temperature.
[0034]
That is, when the temperature of the cleaning liquid is lower than a preset temperature, the steam control valve 16 opens based on the temperature detected by the liquid temperature detecting means 5 and heats the heat exchanger 11 from the steam supply source 13 via the steam supply path 12. The cleaning liquid in the liquid tank 1 is heated by supplying steam and exchanging heat by the heat exchanger 11. On the other hand, when the temperature of the cleaning liquid is heated to a preset temperature or when the temperature of the cleaning liquid is higher than that, the steam control valve 16 is closed based on the temperature detected by the liquid temperature detecting means 5, and the steam supply source 13 The supply of the heating steam to the heat exchanger 11 is stopped, and the cleaning liquid in the liquid tank 1 is maintained at a predetermined temperature by interrupting the heating of the cleaning liquid in the liquid tank 1 by the heat exchanger 11. The cleaning liquid adjusted to the optimum temperature is supplied to the cleaning machine 3 by the pump 2 so that the workpiece is efficiently cleaned.
[0035]
When the steam control valve 16 is opened and heating steam is supplied from the steam supply source 13 to the heat exchanger 11, the check valve 22 is closed by the steam pressure of the supplied heating steam, and the steam supply path 12, When the inside of the heat exchanger 11 and the passage 15 is in a pressurized state and when the steam control valve 16 is closed, the inside of the steam supply passage 12 and the heat exchanger 11 and the passage 15 is caused by the steam pressure of the heating steam from the steam supply source 13. Thus, the pressure P1 in the steam supply path 12, the heat exchanger 11, and the passage 15 is always maintained higher than the liquid pressure P0 of the cleaning liquid stored in the liquid tank 1 (P1> P0). FIG. 2 is an explanatory diagram showing the relationship between the pressure P1 in the heat exchanger 11 and the liquid pressure P0 of the cleaning liquid in a portion corresponding to the heat exchanger 11 in the liquid tank 1.
[0036]
Steam used for heating the cleaning liquid in the heat exchanger 11 and containing condensed water (condensate) is sent to the trap 17 through the passage 15 as the steam control valve 16 is opened, and the condensate is separated by the trap 17. Is done. The condensate separated by the trap 17 is sent to the condensate recovery path 19 and discharged to the drain groove 21.
[0037]
Here, when the cleaning liquid stored in the liquid tank 1 gradually decreases due to continuous workpiece cleaning, and the liquid level detection means 6 detects a preset lower limit liquid level of the cleaning liquid, the condensate supply is based on the detection. The condensate supply valve 26 provided in the path 24 is opened, and the condensate from the condensate recovery path 19 side is supplied from the supply port 36 into the supply liquid tank 31 through the condensate supply path 24 and the supply path 23. . The condensate supplied into the replenisher tank 31 overflows from the discharge port 34 and is supplied as the cleaning liquid into the liquid tank 1, and the liquid level of the condensate in the replenisher tank 31 is held at the storage upper limit position L1. The
[0038]
When the supply of the cleaning liquid is increased by this supply and the liquid level of the condensate in the liquid tank 11 rises and the liquid level detection means 6 detects the preset upper limit liquid level, the condensate supply valve 26 is closed and the replenishment liquid tank is closed. A predetermined amount of cleaning liquid is always held in the liquid tank 1 by stopping the supply due to the overflow from the 31 outlet 34. Further, a predetermined amount of the condensate in the replenisher tank 31 is stored such that the liquid level becomes the storage upper limit position L1.
[0039]
On the other hand, when the liquid level detection means 6 detects the lower limit liquid level and a sufficient amount of condensate is not supplied to the liquid tank 1 even when the condensate supply valve 26 is opened, the condensate supply valve 26 is closed and a process described later is performed. The water control valve 29 is opened to prevent backflow of the industrial water from the water supply source 30 to the discharge groove 21 side, and the industrial water control valve 29 is opened to supply the industrial water from the water supply source 30 instead of the condensate. The liquid is supplied from the replenishing port 36 into the replenishing liquid tank 31 through the path 27, the condensate supplying path 24 and the replenishing path 23. The working water supplied into the replenishing liquid tank 31 overflows from the discharge port 34 and is supplied into the liquid tank 1 as a cleaning liquid. When the supply of the cleaning liquid is increased by this supply and the liquid level detection means 6 detects the upper limit liquid level, the working water control valve 29 is closed and the supply from the replenishment liquid tank 31 to the liquid tank 1 is stopped. A predetermined amount of cleaning liquid is always held in the tank.
[0040]
Therefore, when the cleaning liquid in the liquid tank 1 is reduced to a predetermined amount in normal operation, the cleaning liquid can be replenished with the steam condensate or the working water used for heating the cleaning liquid, thereby ensuring a smooth cleaning operation. Further, the condensate discharged from the heat exchanger 11 can be effectively reused and the amount of industrial water used can be reduced. In particular, condensate can be used more efficiently than industrial water, so that the condensate can be used more efficiently, reducing the amount of industrial water used and reducing the amount of condensate discharged into the drainage groove 21 and the like. can get.
[0041]
When the operation is stopped for a long time, the stop valves 14, 18, 25, 28 are closed, the steam control valve 16 provided in the passage 15, the condensate supply valve 26 provided in the condensate supply path 24, The industrial water control valve 29 of the industrial water supply path 27 is closed.
[0042]
As described above, when the stop valve 14 provided in the steam supply path 12 for supplying the heating steam to the heat exchanger 11 is closed and the steam control valve 16 provided in the passage 15 on the downstream side of the heat exchanger 11 is closed, gradually. The steam remaining in the heat exchanger 11 is condensed, and the pressure P1 in the heat exchanger 11 starts to decrease.
[0043]
FIG. 3 is an explanatory diagram showing the relative relationship between the pressure P1 in the heat exchanger 11 and the liquid pressure P0 of the cleaning liquid in the liquid tank 1. When the stop valve 14 and the steam control valve 16 are closed, the heat exchanger 11 and the steam The steam in the supply passage 12 and the passage 15 starts condensing. Due to the condensation of the steam, the pressure P1 in the heat exchanger 11, the steam supply path 12, and the passage 15 gradually decreases. The pressure P1 in the heat exchanger 11, the steam supply passage 12, and the passage 15 is lowered to the fluid pressure P2 acting on the check valve 22 by the condensate stored in the replenisher fluid tank 31, and more strictly, the fluid pressure P2. When the pressure is further reduced, the check valve 22 opens due to a differential pressure between the hydraulic pressure P2 and the pressure P1 in the heat exchanger 11, the steam supply path 12, and the passage 15, and the replenishing liquid tank is opened via the open check valve 22. The condensate stored in 31 flows into the heat exchanger 11 and the passage 15 from the steam supply path 12, is filled with the condensate, and the pressure P1 in the heat exchanger 11 is maintained at the liquid pressure P2. The liquid pressure P2 is always set higher than the liquid pressure P0 of the cleaning liquid in the liquid tank 1 due to the head difference h (P2> P0) because the replenishment liquid tank 31 is disposed above the liquid tank 1.
[0044]
As the condensate flows into the passage 15, the heat exchanger 11, and the steam supply path 12, the liquid level of the condensate in the replenisher tank 31 decreases from the storage upper limit position L 1 to the reference liquid level position L 2.
[0045]
When the operation is resumed, when the stop valves 14, 25, 28 are opened and the steam control valve 16 is opened to warm the cleaning liquid in the liquid tank 1, the heating steam from the steam supply source 13 is supplied to the steam supply path 12. To be supplied to the heat exchanger 11. The condensate held in the steam supply path 12, the heat exchanger 11, and the passage 15 is sent out from the trap 16 to the condensate recovery path 19 by the steam pressure of the heated steam, and the normal operation is performed as described above.
[0046]
According to the heat exchange system configured as described above, during normal operation, when the cleaning liquid in the liquid tank 1 is heated, the steam control valve 16 is opened and the steam supplied from the steam supply source 13 to the heat exchanger 11 is heated. The check valve 22 is closed by the steam pressure for supplying the steam, and the steam supply path 12, the heat exchanger 11, and the passage 15 are pressurized, and the steam control valve 16 is also closed from the steam supply source 13. The inside of the heat exchanger 11 is maintained in a pressurized state by being pressurized by the heated steam, and the pressure P1 in the heat exchanger 11 is always maintained higher than the liquid pressure P0 of the cleaning liquid in the liquid tank 1 (P1> P0). ).
[0047]
Accordingly, since the pressure P1 in the heat exchanger 11 is always maintained higher than the liquid pressure P0 of the cleaning liquid in the liquid tank 1 during operation, the heat exchanger 11 is temporarily damaged due to corrosion or the like. Even in this case, the cleaning liquid stored in the liquid tank 1 is prevented from entering the heat exchanger 11 through the damaged portion, and the condensate generated by the heat exchanger 11 is not contaminated by the cleaning liquid. .
[0048]
Therefore, the clean condensate discharged from the heat exchanger 11 can be supplied to the liquid tank 1 and reused as a cleaning liquid, and can be used as industrial water for other processing machines. Effective utilization is obtained. Furthermore, even when surplus condensate is discharged to, for example, the outdoor drainage channel 21, the influence on the environment can be avoided.
[0049]
On the other hand, when the operation was stopped, the stop valve 14 provided in the steam supply path 12 was closed to stop the supply of steam to the heat exchanger 11 and provided in the circuit 15 on the downstream side of the heat exchanger 11. When the steam control valve 16 is closed, the steam remaining in the heat exchanger 11 gradually condenses and the pressure P1 in the heat exchanger 11 decreases, but the check valve is caused by the condensate stored in the replenisher tank 31. When the pressure decreases to the hydraulic pressure P2 acting on the valve 22, the check valve 22 opens, the condensate stored in the replenisher tank 31 flows into the heat exchanger 11, and the heat exchanger 11 stores the cleaning liquid in the liquid tank 1. The pressure P2 is maintained higher than the hydraulic pressure P0.
[0050]
Accordingly, since the inside of the heat exchanger 11 is maintained at a pressure P2 larger than the liquid pressure P0 of the cleaning liquid in the liquid tank 1, even if the heat exchanger 11 is damaged such as pinholes due to corrosion or the like, the liquid tank The cleaning liquid stored in 1 is prevented from entering the heat exchanger 11 through the damaged portion, and the heat exchanger 11 is not contaminated by the cleaning liquid and can be reused as the cleaning liquid. Moreover, it can be used as industrial water for other processing machines and the like, and the condensate can be effectively used. Furthermore, even when surplus condensate is discharged to, for example, the outdoor drainage channel 21, the influence on the environment can be avoided.
[0051]
When the heat exchanger 11 is damaged such as pinholes, the condensate filled in the heat exchanger 11 in the operation stop state is the pressure P2 in the heat exchanger 11 and the liquid tank 1. The condensate in the heat exchanger 11 flows out from the damaged portion to the cleaning liquid side of the liquid tank 1 due to the differential pressure of the liquid pressure P0 of the cleaning liquid inside, and the liquid level of the condensate in the replenishing liquid tank 31 is higher than the reference liquid level L2. Gradually descend. The occurrence of damage to the heat exchanger 11 can be known by visually confirming the lowering of the liquid level from the reference liquid level L2.
[0052]
Furthermore, the conventional heat exchange system can be configured without major changes, such as a steam control valve arranged on the upstream side of the heat exchanger in the conventional heat exchange system is arranged on the downstream side of the heat exchanger 11. It can also be applied to existing heat exchange systems without incurring increased equipment costs.
[0053]
In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. For example, in the above embodiment, the liquid level display means 35 of the replenishing liquid tank 31 is formed by shielding the opening 35a formed in the peripheral wall 33 with the transparent plate 35b so that the liquid level can be visually confirmed from the outside. It can also be formed by a float or the like that detects the surface. In the above embodiment, the case where the cleaning liquid is heated has been described as an example. However, other heated liquid stored in the liquid tank is supplied to the heat exchanger disposed in the liquid tank by supplying heating steam. It can also be widely applied to other heat exchange systems that heat.
[0054]
【The invention's effect】
According to the heat exchange system of the present invention described above, the steam supply means connected to the upstream side of the heat exchanger to supply the heating steam to the heat exchanger, and the steam supply connected to the downstream side of the heat exchanger by opening and closing. And a steam control valve for controlling the heating steam supplied from the means to the heat exchanger, so that the heat exchanger is always maintained in a pressurized state by the heating steam from the steam supply means, and is always in the heat exchanger. Is maintained higher than the liquid pressure of the liquid to be heated in the liquid tank. Therefore, even if damage such as pinholes due to corrosion or the like occurs in the heat exchanger, the heated liquid stored in the liquid tank is prevented from entering the heat exchanger through the damaged portion, The liquid to be heated is not mixed into the condensate generated by the heat exchanger.
[0055]
Furthermore, a replenisher tank for storing replenisher liquid is disposed at a position above the liquid tank, and the supply of the heating liquid from the steam supply means to the replenishment path communicating between the replenisher liquid tank and the upstream side of the heat exchanger is stopped. By providing a replenishing liquid control valve that opens when the pressure in the heat exchanger decreases and flows the replenishing liquid in the replenishing liquid tank into the heat exchanger, for example, when the operation is stopped, When the pressure drops, the replenisher control valve opens, the replenisher stored in the replenisher tank flows into the heat exchanger, and the heat exchanger is held at a pressure higher than the liquid pressure of the cleaning liquid in the liquid tank. . Therefore, even when a pinhole or the like is damaged due to corrosion or the like in the heat exchanger, the heated liquid stored in the liquid tank is prevented from entering the heat exchanger through the damaged portion.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of a heat exchange system according to the present invention.
FIG. 2 is an explanatory diagram showing the relationship between the pressure in the heat exchanger and the liquid pressure of the cleaning liquid in the liquid tank during operation.
FIG. 3 is an explanatory diagram showing the relationship between the pressure in the heat exchanger and the liquid pressure of the cleaning liquid in the liquid tank when operation is stopped.
FIG. 4 is an overall view showing an outline of a processing apparatus provided with a conventional heat exchange system.
FIG. 5 is a circuit diagram showing an outline of a conventional heat exchange system.
FIG. 6 is an explanatory diagram showing a relative relationship between the pressure in the heat exchanger and the pressure of the cleaning liquid in the liquid tank when operation is stopped.
[Explanation of symbols]
1 Liquid tank
2 Pump
5 Liquid temperature detection means
6 Liquid level detection means
11 Heat exchanger
11a upstream
11b Downstream side
12 Steam supply path (steam supply means)
13 Steam supply source
14 Stop valve
15 passage
16 Steam control valve
17 Trap
19 Condensate recovery path
20 Check valve
22 Check valve (replenisher control valve)
23 Supply route
24 Condensate supply path
26 Condensate supply valve
31 Replenisher tank
32 Bottom
34 Discharge port
35 Liquid level indicator
36 Supply port

Claims

In a heat exchange system for supplying heating steam to a heat exchanger disposed in a liquid tank for storing a liquid to be heated and heating the liquid to be heated by heat exchange,
A liquid tank for storing the heated liquid;
A heat exchanger disposed in the liquid tank;
Steam supply means connected to the upstream side of the heat exchanger and supplying heated steam to the heat exchanger;
A steam control valve that is connected to the downstream side of the heat exchanger and controls heating steam supplied from the steam supply means into the heat exchanger by opening and closing ;
A replenisher tank that stores replenisher at a position above the liquid tank;
A replenishment path that communicates between a replenishment port that opens at the bottom of the replenisher tank and the upstream side of the heat exchanger;
It opens when the pressure in the heat exchanger decreases due to the supply stop of the heating steam from the steam supply means, and the supply liquid in the supply liquid tank flows into the heat exchanger. A heat exchange system comprising: a replenisher control valve for controlling the replenisher .

The heat exchange system according to claim 1 , wherein the replenishing liquid tank has a liquid level display means for displaying a liquid level of the replenishing liquid stored in the replenishing liquid tank .

The replenisher is a condensate discharged from the heat exchanger,
A condensate supply valve that is arranged between the steam control valve and the replenisher tank and controls the supply of condensate from the heat exchanger side to the replenisher tank by opening and closing;
The said replenishing liquid tank has the discharge port which regulates the storage upper limit position of the condensate stored in this replenishing liquid tank by overflow, and supplies a condensate to the said liquid tank. The described heat exchange system.

The liquid level detection means for detecting the liquid level of the liquid to be heated in the liquid tank, and the condensate supply valve is controlled to open and close based on the liquid level detection of the liquid level detection means. Item 4. The heat exchange system according to Item 3.