JP3710446B2

JP3710446B2 - Backflow prevention device and hot water system equipped with the device

Info

Publication number: JP3710446B2
Application number: JP2002336886A
Authority: JP
Inventors: 清塩谷; 武美木下
Original assignee: 株式会社ダンレイ
Priority date: 2002-10-23
Filing date: 2002-11-20
Publication date: 2005-10-26
Anticipated expiration: 2022-11-20
Also published as: JP2004197955A

Description

【０００１】
【発明の属する技術分野】
本発明は湯や水等の流体を順方向に通水し逆流を遮断する逆流防止装置と、その装置を装備した浴槽への給湯システムに関するものである。
【０００２】
【背景技術】
図９には特許文献１に示された逆流防止装置が示され、図１０にはその逆流防止装置を備えた浴槽１への給湯システム（湯張りシステム）が示されている。この給湯システムは給湯装置としての給湯器２を備え、給水管３を通して供給される水を給湯熱交換器５において給湯バーナ４の燃焼火力によって湯にし、その湯を給湯管６を通して所望の給湯位置に供給する。
【０００３】
前記給湯管６には分岐管７が接続され、この分岐管７に供給された湯は、逆流防止装置１０を順方向に流通し落し込み管８を通して浴槽１に落とし込まれる。なお、図１０中の、１１はフローセンサ、１２は電磁弁、１３は逆止弁をそれぞれ示している。
【０００４】
図９、図１０に示されるように、逆流防止装置１０の流入通路１４には分岐管７が接続され、流出通路１５には落し込み管８が接続され、一次圧導入口１６には一次圧供給管９の出口が接続されている。一次圧供給管９の入口側は給水管３に接続され、この給水管３側の水道圧が一次圧力として一次圧導入口１６に印加されている。
【０００５】
給湯器２の湯を浴槽１へ落とし込む動作時においては、一次圧供給管９からの一次圧を受けて、ピストン１７が図の左方向へ移動して弁１８が壁面１９に当接することで空気導入管２０の空気導入通路２１が閉鎖（通路１４、１５と空気導入通路２１との連通が遮断）され、この状態で、分岐管７から供給される湯は流入通路１４から流出通路１５を経て落し込み管８に入り、浴槽１に落とし込まれる。この状態で、例えば給水管３側が断水等により負圧化（落し込み管８側の圧力よりも給水管３側の圧力が低下した状態）になると、ピストン１７は右方へ移動して図９の状態となり、空気導入通路２１から空気が入り込み、流入通路１４及び流出通路１５を大気圧に開放する。このことで、たとえ、逆止弁１３に異常が生じて逆止弁１３による逆流防止機能が正常に働かなかったとしても、浴槽１側からの汚水が分岐管７を介して給水管３側に逆流するのを防止しようとするものである。また、空気導入管２０は下方向きに設けられ、たとえ浴槽１側の汚水が逆流したとしても、その汚水を空気導入通路２１から排水し、汚水が流入通路１４側へ流れるのを防止しようとするものである。
【０００６】
図１１は特許文献２に示されている逆流防止装置１０を示すもので、この装置も図１０に示されるような給湯システム（逆止弁１３は除去されている）に使用される。図１１は給湯器の湯を浴槽へ落とし込みしている動作状態を示し、給湯器側から流入通路１４に入り込んだ湯は、流入の一次圧力によって逆止弁２２、２３を開けて弁室２４を通り、流出通路１５から落し込み管８（図１０参照）を経由して浴槽に湯が落としこまれる。このとき、ダイアフラム応動弁２５の背圧室２６には連通路２７を介して流入通路１４側から一次圧が供給されているので、ダイアフラム２８は弁室２４側に撓み変形し、これに伴い可動弁体２９はその撓み変形方向に移動して弁板３０が固定弁体３１に当接されて空気導入通路２１と弁室２４との連通は遮断状態を維持する。
【０００７】
一方、断水等により、流入通路１４側が負圧化すると、逆止弁２２、２３が閉じ、逆流を防止するが、たとえ、この逆止弁２２、２３が共に異常となって逆流防止動作が正常に働かない状態となっても、前記負圧化によって背圧室２６の圧力が低下するので、ダイアフラム２８は空気導入通路２１側へ変位し、それに伴い可動弁体２９も同方向へ変位することで、弁板３０が固定弁体３１から離れ、空気導入通路２１から弁室２４へ空気が導入される結果、弁室２４は大気に開放され逆流が防止されると共に、空気導入通路２１は下方に向けられているので、弁室２４に逆流した汚水は空気導入通路２１から排水され、汚水が流入通路１４側へ入り込むのを防止できるというものである。
【０００８】
【特許文献１】
特開２０００−３０４１４４号公報
【特許文献２】
特開平７−２２４９５６号公報
【０００９】
【発明が解決しようとする課題】
しかしながら、特許文献１に開示されている逆流防止装置は分岐管７と落し込み管８と一次圧供給管９との３本の管路が接続される構成であるため、配管接続作業が大変であり、配管構成が複雑になるという問題がある。さらに、空気導入通路２１は排水通路としての機能を兼用させており、その結果、例えば、浴槽１への湯張りの途中で断水が生じたような場合に、逆止弁１３に異常があって浴槽１側の汚水が逆流した場合、ピストン１７が弁開方向に移動して装置内の通路１４、１５を空気導入通路２１に連通しようとしたとしても、装置内の流体（水）が空気導入通路２１から外に排出されようとするために、その排水の流れる方向と外部から空気が入り込む方向とが逆向きとなり、空気導入通路２１の断面積の全体を占めて流れ出ようとする排水に逆らって外から空気導入通路２１に空気が入り込むことが困難となる。そのため、装置内通路の大気開放のタイミングが遅れ、落し込み管８側から分岐管７側へ浴槽１側の汚水が入り込んで、給水管３側にその汚水が混入するという危険があり、衛生安全上問題となる。
【００１０】
また、特許文献２に開示された逆流防止装置も空気導入通路２１は排水通路を兼用しているので同様の問題がある。また、特許文献２の装置は、弁室２４内に、逆止弁２２、固定弁体３１等の装置構成要素を複数収容配備した複雑な構造を呈しているので、装置製造が容易でなく、装置も大型化し、装置コストも高くなるという問題がある。さらに、特許文献２に示された装置において、流入通路１４に接続される管路の上流側の弁（例えば図１０に示されるような電磁弁１２）が閉じられている給湯待機状態時にあっては、流入通路１４側の圧力（背圧室２６の圧力）と弁室２４の圧力とがほぼ同圧となり、そのため、ばね３２の付勢力を受けて可動弁体２９が固定弁体３１から離れた開弁位置になるので、空気導入通路２１と弁室２４は連通状態に維持されたままとなり、空気導入通路２１を通して外部から塵埃等の異物が弁室２４内に入り込むという問題がある。
【００１１】
本発明は上記従来の課題を解決するためになされたものであり、その目的は、流入通路と流出通路に配管接続するだけで（２本の管路を接続するだけで）浴槽等へ湯を供給する給湯システムに設置することが可能で、給湯待機状態時に装置内（弁室）に塵埃が入り込むことなく、また、断水時等のように一次圧力（給水側圧力）が低下した場合には確実に弁室内を大気開放して流出通路側からの逆流を防止することが可能で、装置構成の簡易化、小型化、低コスト化が可能な逆流防止装置およびその装置を装備した給湯システムを提供することにある。
【００１２】
【発明を解決するための手段】
本発明は上記目的を達成するために次のような構成をもって課題を解決する手段としている。すなわち、第１の発明は、装置内に、流入通路と、この流入通路からの流入流体をメーン弁室に導入するメーン導入通路と、前記メーン弁室の出口側に連通して前記流入流体を流出する流出通路とを有し、前記メーン導入通路の入口部には開弁によって流入通路からの流入流体を導入し閉弁によって流入流体の導入を遮断するメーン制御弁が設けられ、前記メーン弁室の入口側と出口側にはそれぞれ流入流体の流入順方向圧力によって開弁し逆流を閉弁によって阻止する逆流防止弁が設けられており、また、装置内には縁切り室が設けられ、この縁切り室はダイアフラムを介して縁切り背圧室と前記メーン弁室に連通する負圧開放室とに区分され、この負圧開放室には外部の空気を導入する空気導入通路が縁切り弁を介して連通され、前記縁切り背圧室は装置内に形成された一次圧連通通路を介して前記流入通路に連通されており、前記縁切り弁は常時は前記縁切り背圧室に印加される流入通路側の一次圧を受けて前記ダイアフラムを負圧開放室側に撓み変形させることで縁切り弁を閉じて前記空気導入通路とメーン弁室との連通を遮断し、前記流入通路が低圧化された時に前記ダイアフラムがその低圧化に応じた圧力を前記縁切り背圧室側から受けて該縁切り背圧室側に撓み復帰変形することで前記縁切り弁を開き前記空気導入通路とメーン弁室とを連通させて前記メーン弁室を大気に開放するダイアフラム応動弁とした構成をもって課題を解決する手段としている。
【００１３】
また、第２の発明は、装置内に、流入通路と、この流入通路からの流入流体をメーン弁室に導入するメーン導入通路と、前記メーン弁室の出口側に連通して前記流入流体を流出する流出通路とを有し、前記メーン導入通路の入口部には開弁によって流入通路からの流入流体を導入し閉弁によって流入流体の導入を遮断するメーン制御弁が設けられ、前記メーン弁室の入口側と出口側にはそれぞれ流入流体の流入順方向圧力によって開弁し逆流を閉弁によって阻止する逆流防止弁が設けられており、また、装置内には縁切り室と排水室とが設けられ、前記縁切り室はダイアフラムを介して縁切り背圧室と前記メーン弁室に連通する負圧開放室とに区分され、この負圧開放室には外部の空気を導入する空気導入通路が縁切り弁を介して連通され、前記縁切り背圧室は装置内に形成された一次圧連通通路を介して前記流入通路に連通されており、前記縁切り弁は常時は前記縁切り背圧室に印加される流入通路側の一次圧を受けて前記ダイアフラムを負圧開放室側に撓み変形させることで縁切り弁を閉じて前記空気導入通路とメーン弁室との連通を遮断し、前記流入通路が低圧化された時に前記ダイアフラムがその低圧化に応じた圧力を前記縁切り背圧室側から受けて該縁切り背圧室側に撓み復帰変形することで前記縁切り弁を開き前記空気導入通路とメーン弁室とを連通させて前記メーン弁室を大気に開放するダイアフラム応動弁として構成し、前記排水室はダイアフラムを介して排水背圧室と前記流出通路に連通する排水処理室とに区分され、この排水処理室は排水弁を介して排水通路に連通され、前記排水背圧室は装置内に形成された一次圧連通通路を介して前記流入通路に連通されており、前記排水弁は常時は前記排水背圧室に印加される流入通路側の一次圧を受けて前記ダイアフラムを排水処理室側に撓み変形させることで排水弁を閉じて前記排水通路と前記流出通路との連通を遮断し、前記流入通路が低圧化された時に前記ダイアフラムがその低圧化に応じた圧力を前記排水背圧室側から受けて該排水背圧室側に撓み復帰変形することで前記排水弁を開き前記流出通路と排水通路とを連通させるダイアフラム応動弁とした構成をもって課題を解決する手段としている。
【００１４】
さらに、第３の発明は、前記第２の発明の構成を備えたものにおいて、メーン導入通路と、メーン弁室と、流出通路とを順に通る流路は直線状の流路と成し、前記メーン弁室の外周側領域に縁切り室と排水室とが分離して形成され、流入通路の出口側はメーン制御弁を介してメーン導入通路に導かれる通路と、前記縁切り背圧室及び排水背圧室とに導かれる一次圧連通通路とに連通され、前記メーン制御弁の開閉に依存せずに流入通路側の一次圧によって常時縁切り弁と排水弁を閉じ、前記一次圧が低圧化した異常時にのみ前記縁切り背圧室と排水背圧室の圧力低下に依存して縁切り弁と排水弁を開放する構成としたことを特徴とする。
【００１５】
さらに、第４の発明は、前記第３の発明の構成を備えたものにおいて、縁切り室と排水室は同一形状に形成され、縁切り室の縁切り背圧室に連通する空気導入通路と排水室の排水処理室に連通する排水通路は共にメーン導入通路から流出通路に至る直線状の流路に沿い同流路の下流側に向けて延設されていることを特徴とする。
【００１６】
さらに、第５の発明は、前記第１又は第２又は第３又は第４の発明の構成を備えたものにおいて、空気導入通路が縁切り弁を介して負圧開放室に連通される構成に代えて、空気導入通路は直接的に負圧開放室に連通され、負圧開放室は縁切り弁の弁孔のみを介してメーン弁室に連通されていることを特徴とする。
【００１７】
さらに、第６の発明は、給湯システムに関し、この給湯システムは、給湯装置から浴槽に湯を供給する通路の途中に前記第２又は第３又は第４又は第５の発明の逆流防止装置が介設されていることを特徴とする。
【００１８】
さらに、第７の発明は、給湯システムに関し、この給湯システムは、給湯装置から浴槽に湯を供給する通路の途中に前記第１の発明の逆流防止装置が介設され、この逆流防止装置よりも下流側の通路に浴槽側から逆流した流体を排水する排水装置が外付け設置されていることを特徴とする。
【００１９】
【発明の実施の形態】
以下、本発明の実施形態例を図面に基いて説明する。なお、以下の説明において、前記の従来例を含み、共通の構成部分には共通の符号を付してその重複説明は省略又は省略する。
【００２０】
図１には本発明に係る逆流防止装置の第１の実施形態例が示され、図５にはその逆流防止装置５０を装備した給湯システムの一実施形態例が示されている。図１に示すように、この実施形態例の逆流防止装置５０は筒形状をした本体外部ボデイ５１の上部側に流入側ボデイ４２の基端側が嵌合装着され、その流入側ボデイ４２の内部に導入通路形成部材４３が挿入された構造を有している。なお、この実施形態例の説明において、上、下の用語は図１の装置姿勢の状態で使用しており、実際の装置使用時の上下の概念とは必ずしも一致しない。
【００２１】
流入側ボデイ４２は上下方向の筒壁とその上下方向の筒壁の上部側から横方向に伸設されて分岐した流入通路形成筒部４５を有しており、流入通路形成筒部４５の筒孔は流入通路１４として機能している。この流入通路１４には流量を検出するフローセンサ４６が必要に応じ配置される。流入側ボデイ４２の上下方向の筒壁の上端側にはメーン制御弁が設けられる。このメーン制御弁は導入通路形成部材４３の筒孔によって形成されるメーン導入通路４４の上端部の弁座４７の開口を制御開閉する機能を有するものであればどのような弁であってもよいが、この図１の例ではパイロット電磁弁４８がメーン制御弁として用いられ、流入側ボデイ４２の上端にねじ５２を用いて固定されている。
【００２２】
この種のパイロット電磁弁の構成は周知であるので、その説明は簡略化するが、摺動ロッド４９の下端側に弁体５３がダイアフラム５４に支持されて配置されており、常時はばね５６の下方への付勢力を受けて弁体５３の弁板５７が弁座４７に当接し、メーン導入通路４４を閉鎖している。ソレノイドコイル５５が駆動されると、摺動ロッド４９はばね５６の付勢力に抗して上方へ移動し、弁体５３を上方移動させてメーン導入通路４４の上端側の弁座４７の開口を開放して開弁するものである。
【００２３】
前記流入側ボデイ４２には外周に鍔部１２７が形成されており、この鍔部１２７が本体外部ボデイ５１の上端に係止されて位置決めされている。また、流入側ボデイ４２の外周面には係止溝１２８が周設されている。本体外部ボデイ５１側には係止溝１２８の内部を左右両側の位置で貫通する一対のピン穴がほぼ平行に貫通形成され、このピン穴にＵ字形状の係止ピン１２９が外側から挿入されることで、係止ピン１２９は前記係止溝１２８を挿通し、流入側ボデイ４２は本体外部ボデイ５１に対して首振り回転移動が自在に係止されている。勿論、流入側ボデイ４２と本体外部ボデイ５１とはボルト等の適宜の締結手段を用いて固定される構成としてもよい。本体外部ボデイ５１の筒孔内壁には内側に突き出す段部５８が形成されており、この段部５８の上面に導入通路形成部材４３の下端が係止して導入通路形成部材４３は本体外部ボデイ５１内に配置されている。前記メーン導入通路４４の下端には下方に突き出す弁座６５が形成されている。なお、流入側ボデイ４２と本体外部ボデイ５１との嵌合面、および導入通路形成部材４３と本体外部ボデイ５１との嵌合面には適宜の位置にＯリングが介設されて気密嵌合が達成されている。
【００２４】
前記本体外部ボデイ５１の筒孔には前記段部５８よりも下方位置にさらに内側に突き出す段部５９が設けられ、この段部５９に係止されて、弁座形成筒部材６０が導入通路形成部材４３の下方部に配置されている。この弁座形成筒部材６０の筒孔の下方部には内側に突き出す段部６２が形成され、弁座形成筒部材６０の下端部には下方に突き出す弁座６１が形成されている。また、段部６２よりも上方側の真直筒壁には透孔６３が形成され、この透孔６３に対向する本体外部ボデイ５１の筒壁にも透孔６４が形成されている。なお、弁座形成筒部材６０と本体外部ボデイ５１との嵌合壁面間にも適宜Ｏリング等の気密手段が介設されて気密嵌合が達成されている。
【００２５】
前記弁座形成筒部材６０の筒壁面には前記段部５９よりも下方位置にさらに内側に突き出す段部６６が形成されている。そして、段部６２と弁座６５間の筒孔空間には第１の逆流防止弁が、段部６６と弁座６１との間の筒孔空間には第２の逆流防止弁がそれぞれ設けられている。これらの逆流防止弁は順方向（図では上から下に向かう方向）の通水時にはその給水源側圧力（一次側圧力）によって弁を開き、給水源側圧力が負圧化（下流側圧力（二次側圧力）よりも低圧化）したときに閉弁して逆流を防止する機能を備えた弁であればどのような弁でもよいが、図示の例では、共に逆止弁が使用されている。すなわち、第１の逆流防止弁として第１の逆止弁６７が使用され、第２の逆流防止弁として第２の逆止弁６８が使用されている。これらの逆止弁６７、６８は同一構成と成している。
【００２６】
これらの逆止弁６７、６８は支持ベース６９と弁体７０とを有して構成され、支持ベース６９はベース板７１の中心部に上方へ突き出す筒軸７２を設けたもので、ベース板７１には複数の透孔７３を形成し、筒軸７２の中心孔に弁体７０の中心ロッド７４が摺動自在に挿通されている。中心ロッド７４の上端には鍔板部７５が形成され、この鍔板部７５の上面に弁板７６がねじ止め固定されている。そして、ベース板７１と鍔板部７５の下面間には圧縮変形されたばね７７が介設されている。第１の逆止弁６７の支持ベース６９は段部６２に配置され、ばね７７の上方への付勢力を受けて弁板７６は弁座６５に当接して弁座６５の開口（弁孔）が閉鎖されている。同様に、第２の逆止弁６８の支持ベース６９は段部６６に配置され、ばね７７の上方への付勢力を受けて弁板７６は弁座６１に当接して弁座６１の開口（弁孔）が閉鎖されている。
【００２７】
本体外部ボデイ５１の下方側の筒孔には流出通路形成筒部７８が挿入固定され、この流出通路形成筒部７８の中心孔は流出通路１５と成している。この流出通路形成筒部７８も適宜Ｏリング等の気密手段を用いて本体外部ボデイ５１に気密に挿入装着されている。なお、図示の例では、前記係止溝１２８と係止ピン１２９とを用いた流入側ボデイ４２と本体外部ボデイ５１との係止構成と同様に、係止溝１３０と係止ピン１３１との係止構成により流出通路形成筒部７８は本体外部ボデイ５１に対し首振り回転移動が自在に係止されている。
【００２８】
本体外部ボデイ５１の外周面の分離した位置、図示の例では左右反対側となる位置にそれぞれ凹部７９、８０が設けられている。これらの凹部７９、８０の開口側となる本体外部ボデイ５１の外面にはそれぞれダイアフラム８１、８２が取り付けられており、凹部７９はダイアフラム８１によって気密に覆われ、凹部８０はダイアフラム８２によって気密に覆われている。そして、これらダイアフラム８１、８２の配置領域の外側は空間を介して本体外部ボデイ５１の外側に気密に装着されたカバー部材８３によって覆われている。
【００２９】
前記凹部７９の中央領域表面にはダイアフラム８１側に突出する弁座８４がリング状に周設されている。弁座８４に対向する部位のダイアフラム８１の領域は肉厚に形成されて弁部８５と成し、この弁部８５の中心孔に空気導入管８６の基端部が取り付け板８７を用いて気密に固定されている。空気導入管８６の先端側はカバー部材８３の筒部８８内にＯリングを介して気密に嵌入され、空気導入管８６の中心孔は空気導入通路２１と成して外部に通じている。
【００３０】
前記弁座８４とこれに対向する弁部８５は縁切り弁８９として機能し、この縁切り弁８９の外側部分の凹部７９とダイアフラム８１によって囲まれた空間は負圧開放室９０と成している。また、ダイアフラム８１とカバー部材８３とによって囲まれた空間は縁切り背圧室９１と成し、この縁切り背圧室９１と負圧開放室９０とによって縁切り室９２が形成されている。つまり、縁切り室９２はダイアフラム８１によって、負圧開放室９０と縁切り背圧室９１とに区分された構成と成している。
【００３１】
前記弁座形成筒部材６０の内部空間領域はメーン弁室９３と成し、このメーン弁室９３の入口は第１の逆止弁６７によって開閉され、メーン弁室９３の出口は第２の逆止弁６８によって開閉される構成と成している。この実施形態例においては、メーン導入通路４４とメーン弁室９３と流出通路１５は前記逆止弁６７、６８を介して連続する直線通路と成している。メーン弁室９３は透孔６３、６４を介して負圧開放室９０に連通しており、空気導入通路２１と負圧開放室９０は縁切り弁８９を介して連通する結果、空気導入通路２１とメーン弁室９３とは縁切り弁８９を介して連通する構成と成している。
【００３２】
凹部８０側の本体外部ボデイ５１の壁部には外側（ダイアフラム８２側）に突き出す弁座９４が設けられており、この弁座９４に対向するダイアフラム８２の部位は肉厚に形成されて弁部９６と成しており、この弁座９４と弁部９６とによって排水弁９９が形成されている。本体外部ボデイ５１の壁面とダイアフラム８２によって囲まれた凹部８０の空間は排水処理室１００として機能し、また、ダイアフラム８２とカバー部材８３とによって囲まれる空間は排水背圧室１０１として機能している。つまり、ダイアフラム８２の外側を囲むカバー部材８３の内部空間は排水室１０２と成し、この排水室１０２はダイアフラム８２によって排水処理室１００と排水背圧室１０１とに区分された構成と成している。
【００３３】
排水処理室１００は弁座９４の弁孔９５および第２の逆止弁６８の透孔７３を介して流出通路１５に連通している。ダイアフラム８２の弁部９６の外側部分にはばね受け板９７が取り付けられており、このばね受け板９７と本体外部ボデイ５１の壁面（凹部８０の底壁面）との間には圧縮状のばね９８が配置されている。このばね９８は弁孔９５を開放する方向の付勢力を弁部９６に作用する。なお、ダイアフラム８１とダイアフラム８２は別体でもよく、共通の一体物でもよい。
【００３４】
前記排水弁９９側の本体外部ボデイ５１の下端には筒部１０３が形成され、この筒部１０３に配水管１０４が嵌合装着されており、この配水管１０４の先端は外部に通じ、流出通路１５から逆流してきた水を第２の逆止弁６８の透孔７３、弁孔９５を介して排水処理室１００に導入し、さらに、排水処理室１００から配水管１０４の排水通路１０５を通して外部へ排水する構成と成している。
【００３５】
前記導入通路形成部材４３の外周とそれに対面する流入側ボデイ４２の内周面との間には流入通路１４に連通する流通路１０６が形成されている。この流通路１０６の上部側は流入通路１４とメーン導入通路４４をパイロット電磁弁４８の弁部を介して連通する通路と成し、流通路１０６の下方側に向かう通路は流入通路１４を縁切り背圧室９１および排水背圧室１０１に連通する一次圧連通通路１０７と成している。一次圧連通通路１０７と縁切り背圧室９１とは本体外部ボデイ５１に設けた透孔１０８を介して連通し、一次圧連通通路１０７と排水背圧室１０１とは本体外部ボデイ５１に設けた透孔１０９を介して連通する。
【００３６】
上記構成の逆流防止装置５０は図５に示すように給湯システムに組み込まれて使用される。この給湯システムは前記図１０に示した給湯システムと同様に給湯熱交換器５で作り出した湯を浴槽１に落とし込む機能を有するもので、逆流防止装置５０の流入通路形成筒部４５が分岐管７に接続され、逆流防止装置５０の流出通路形成筒部７８が落し込み管８に接続されることで、逆流防止装置５０は給湯システムに組み込まれる。本実施形態例の給湯システムは浴槽１に追い焚き循環路３３が接続されており、落し込み管８から供給される湯はこの追い焚き循環路３３を介して浴槽１に落とし込まれる構成と成している。追い焚き循環路３３を備えた風呂の追い焚き装置は周知であるので、簡単に説明すると、循環ポンプ３７を駆動して戻り管３４から浴槽１の湯を引き出し、追い焚き熱交換器３５を通して往管路３６から浴槽１に循環させる。この循環の湯の流れを検知して追い焚きバーナ３８を燃焼駆動し、その燃焼火炎によって追い焚き熱交換器３５を通る湯を加熱し、浴槽１の湯を昇温し、浴槽１の湯温が風呂の設定温度に達したときに循環ポンプ３７を停止して追い焚き動作を停止するものである。
【００３７】
勿論、本実施形態例の逆流防止装置５０は図１０に示すように追い焚き循環路３３を設けずに直接的に落し込み管８から浴槽１に湯を供給する構成としてもよいものである。なお、図５中、３９は器具ケースを示している。
【００３８】
次に、図１、図５に基いて逆流防止装置５０の動作を説明する。給湯器２側から浴槽１への湯の落し込みがされない状態の時は、パイロット電磁弁４８は閉動作され、メーン導入通路４４の入口は弁板５７によって閉じられている。この状態にあって、流入通路１４は一次圧連通通路１０７を介して縁切り背圧室９１および排水背圧室１０１に連通され、縁切り背圧室９１および排水背圧室１０１には給水源側の水圧（水道圧）が一次圧として印加され、縁切り弁８９側では、この一次圧を受けてダイアフラム８１が弁座８４側に撓み変形して弁部８５は弁座８４に圧接（当接）し、縁切り弁８９は閉じられている。つまり、空気導入通路２１と負圧開放室９０（メーン弁室９３）との連通が遮断されている。同様に、排水弁９９側も、一次圧を受けてダイアフラム８２がばね９８の付勢力に抗して弁座９４側に撓み変形し、弁部９６が弁座９４に圧接して排水弁９９が閉じられており、排水処理室１００（排水通路１０５）側と流出通路１５側との連通が遮断されている。
【００３９】
この状態で、パイロット電磁弁４８の開駆動が行なわれると、弁板５７が弁座４７から上方へ離れ移動して開弁される結果、流入通路１４から入り込む湯はメーン導入通路４４に導入される。そして、給水圧力（一次圧）により、第１の逆止弁６７、第２の逆止弁６８が開けられて、湯はメーン弁室９３を通り流出通路１５から落し込み管８に入り込み、追い焚き循環路３３を介して浴槽１に落とし込まれる。この湯の落し込み期間においても、縁切り背圧室９１および排水背圧室１０１には一次圧が印加維持されているので、縁切り弁８９と排水弁９９は共に閉状態を維持している。
【００４０】
この湯の落し込みの途中で一次圧が低下する異常、例えば断水が生じると、流出通路１５側の圧力（二次圧）よりも流入通路１４側の圧力（一次圧）が低圧化（負圧化ともいう）することから、浴槽１側の湯水は給水管３側に吸引されて逆流しようとする。このとき、第１の逆止弁６７と第２の逆止弁６８は閉動作して逆流を防止するが、例えば、弁板７６と対応する弁座６５、６１との間に異物が噛み込む等の何らかの異常により、逆止弁６７、６８の逆流動作が正常に行なわれない場合においても、本実施形態例の逆流防止装置５０においては次の動作により逆流を確実に防止する。
【００４１】
すなわち、縁切り背圧室９１と排水背圧室１０１は流入通路１４に連通されているので、縁切り背圧室９１と排水背圧室１０１の圧力は低圧化（負圧化）する。つまり、縁切り弁８９側においては、負圧開放室９０側の圧力が縁切り背圧室９１の圧力よりも高くなり、また、ダイアフラム８１には弁部８５が弁座８４から離れる方向の弾性復帰の復元力が作用して縁切り弁８９が開かれ（弁部８５が弁座８４から離れ）、空気導入通路２１から外部の空気が負圧開放室９０を介してメーン弁室９３に導入される結果、メーン弁室９３は大気に開放されて、所謂、流出通路１５側と流入通路１４側との縁切りが達成されて流出通路１５側の汚水が流入通路１４側へ逆流するのが確実に防止される。
【００４２】
このように、縁切り弁８９は常時は縁切り背圧室９１に印加される流入通路１４側の一次圧を受けてダイアフラム８１を負圧開放室９０側に撓み変形させることで縁切り弁を閉じて空気導入通路２１とメーン弁室９３との連通を遮断し、流入通路１４が低圧化された時にダイアフラム８１がその低圧化応じた圧力を縁切り背圧室９１側から受けて該縁切り背圧室９１側に撓み復帰変形することで縁切り弁を開き空気導入通路２１とメーン弁室９３とを連通させてメーン弁室９３を大気に開放するダイアフラム応動弁として構成してある。
【００４３】
一方、排水弁９９側においても、排水背圧室１０１が低圧化するので、ばね９８の付勢力による開弁方向の力、および流出通路１５側からの二次圧による開弁方向の力が閉弁方向の力に打ち勝って、ダイアフラム８２は弁部９６が弁座９４から離れる方向に弾性復帰変形して開弁されるので、たとえ、浴槽１側の汚水が逆流してきたとしても、その汚水は弁孔９５から排水処理室１００を経て排水通路１０５に入り込んで外部へ排水されるので、汚水が流入通路１４側へ逆流することは確実に防止される。
【００４４】
このように、排水弁９９は常時は排水背圧室１０１に印加される流入通路１４側の一次圧を受けてダイアフラム８２を排水処理室１００側に撓み変形させることで排水弁を閉じて排水通路１０５と流出通路１５との連通を遮断し、流入通路１４が低圧化された時にダイアフラム８２がその低圧化に応じた圧力を排水背圧室１０１側から受けて排水背圧室１０１側に撓み復帰変形することで排水弁を開き流出通路１５と排水通路１０５とを連通させるダイアフラム応動弁として構成してある。
【００４５】
本実施形態例の逆流防止装置５０によれば、給湯システムに組み込む際には、分岐管７と落し込み管８との２本の管に接続するだけでよいので、図１０に示されるような分岐管７と、落し込み管８と、一次圧供給管９との３本の配管に接続する構成のものに比べ、給湯システムへの組み込み作業が容易となるだけでなく、配管構成を単純化することが可能となる。
【００４６】
また、パイロット電磁弁４８の動作状態の如何にかかわらず（パイロット電磁弁４８が開状態にあるか閉状態にあるかにかかわらず）、流入通路１４側の一次圧が一次圧連通通路１０７を介して縁切り背圧室９１および排水背圧室１０１に印加するように構成しているので、流入通路１４側が低圧化する異常が生じない限り、縁切り弁８９と排水弁９９は一次圧を利用して常時閉状態に維持することができ、メーン弁室９３を含む内部の湯の流通通路内に空気導入通路２１や排水通路１０５を介して外部の塵埃等の異物が入り込むのを阻止し、この異物が逆止弁６７、６８の弁板７６と対応する弁座６５、６１に噛み込む等の不具合を防止することができる。
【００４７】
さらに、流入通路１４側が低圧化する異常が生じた場合は、縁切り背圧室９１および排水背圧室１０１の負圧化を利用して縁切り弁８９と排水弁９９を共に開け、縁切り弁８９の開弁によりメーン弁室９３を大気開放して縁切りし、汚水が逆流してきたとしても、排水弁９９からその汚水を排水するので、汚水が流入通路１４側へ逆流するのを確実に防止することができる。このように、縁切り弁８９と排水弁９９は共に背圧室側を流入通路１４に連通し、正常時には一次圧によって弁を閉じ、一次圧が低下する異常時にはその一次圧の低下圧力を利用して開弁するという如く、流入通路１４側の一次圧を縁切り弁８９および排水弁９９の開閉駆動源として利用する構成としたので、装置構成が簡易化し、装置の小型化、装置コストの低減化が達成できると共に、電磁弁等のような電気部品の使用がないので、停電の影響を受けずに縁切りと排水の動作を確実に行い得るので、信頼性も非常に高い。
【００４８】
特に、本実施形態例の逆流防止装置５０は空気導入通路２１と排水通路１０５とを別個独立の専用通路と成しているので、流入通路１４側が低圧化（負圧化）したときに、流れの方向が逆向きとなる空気導入流と排水流とが交錯して互いの動作を妨げるように干渉し合うことがないので、縁切り動作と、排水動作を応答よく迅速に行なうことができるという効果を奏するものである。
【００４９】
図２、図３は本実施形態例の逆流防止装置５０の変形例を第２、第３の実施形態例として示した図である。その第１の変形形態としての第２の実施形態例は、図２に示すように、流出通路形成筒部７８の流出通路１５内に追加の逆止弁１１０を逆流防止弁として設けたことである。このように、逆止弁１１０を追加し、３段の逆止弁６７、６８、１１０の配置構成とすることにより、逆流防止の効果を一層高めることができるものである。
【００５０】
第２の変形形態としての第３の実施形態例は、図３に示すように、排水背圧室１０１内の弁部９６とカバー部材８３との間に圧縮状のばね１１１を配置し、その代わり、図１に示されているばね９８を取り去り、このばね１１１により、弁部９６を弁座９４側へ付勢する閉弁方向の力を作用させるようにしたことである。この構成により、流入通路１４側が負圧化（低圧化）しない正常時には、排水弁９９は流入通路１４側の一次圧とばね１１１との付勢力によって閉弁し、流入通路１４側が負圧化した異常時には、一次圧の負圧化圧力がばね１１１の付勢力に打ち勝って開弁する構成とする。これら第１、第２の変形形態以外の構成、効果は前記図１に示した構成、効果と同一であり、その重複説明は省略する。なお、第２、第３の実施形態例の装置も前記第１の実施形態例の装置と同様に様々な給湯システムに組み込まれて使用される。
【００５１】
図４は本発明に係る逆流防止装置５０の第４の実施形態例を示す。この第４の実施形態例の装置も前記第１〜第３の実施形態例の装置と同様に様々な給湯システムに組み込まれて使用されるが、この第４の実施形態例が前記第１〜第３の実施形態例と異なる点は、縁切り室９２と排水室１０２を同一形状に形成して装置の小型化、装置構成の簡素化を一層進め、さらに、縁切り弁８９の弁動作の応答性を一層高めた構成としたことであり、それ以外の構成は前記第１〜第３の実施形態例と同様であり、共通構成の重複説明は省略する。
【００５２】
第４実施形態例においては、本体外部ボデイ５１の外周面に形成する凹部７９と凹部８０との位置を上下方向にずらし、凹部８０を凹部７９よりも下方位置に形成してある。そして、凹部７９側に形成される縁切り弁８９と凹部８０側に形成される排水弁９９は同一構成となしている。すなわち、凹部７９と凹部８０の形状は同一であり、負圧開放室９０は排水処理室１００と同一形状であり、縁切り背圧室９１と排水背圧室１０１も同一形状であり、弁座８４は弁座９４と同一形状である。また、縁切り弁８９の弁孔９５ａは排水弁９９の弁孔９５ｂと同一形状である。ダイアフラム８１とダイアフラム８２も同一形状であり、カバー部材８３ａとカバー部材８３ｂも同一形状である。
【００５３】
このように縁切り弁８９と排水弁９９を同一形状（同一構成）とすることにより、ダイアフラム８１とダイアフラム８２は同一部品の使用が可能となり、カバー部材８３ａとカバー部材８３ｂも同一部品の使用が可能となり、部品管理が容易になるとともに、凹部７９と凹部８０の形状が同じなので、金型等による凹部７９、８０の形成も容易となり、装置の生産性を高めることができる。
【００５４】
また、第４の実施形態例においては、装置構成の簡素化を図るため、ダイアフラム８１、８２はその外周端縁を本体外部ボデイ５１の外周面とカバー部材８３ａ、８３ｂの内面間に挟持固定した簡素な固定構造とされており、このようにすることで、例えば図１に示されるような、ダイアフラム８１を取り付けるための、取付け板８７、ばね受け板９７、空気導入管８６を縁切り室９２内に設ける必要がなく、また、図１の排水室１０２側に設けられているようなばね受け板９７とばね９８も不用としているため、部品点数も少なくでき、装置構成の簡素化が達成されている。その上、図１に示される筒部８８のようなカバー部材８３から横方向への突き出し部もないため、装置の小型化が達成されている。
【００５５】
さらに、第４の実施形態例においては、排水通路１０５は弁孔９５ｂのみを通して第２の逆止弁６８の下流部分と連通され、メーン弁室９３は弁孔９５ａのみを通して空気導入通路２１に連通される構成と成している。このため、縁切り弁８９と排水弁９９が閉じられている状態においては、メーン弁室９３側からの圧力を弁孔９５ａの部分で受けるダイアフラム８１の受圧面積よりも縁切り背圧室９１からの圧力を受けるダイアフラム８１の受圧面積が遥かに大きく（弁孔９５ａ側から受ける圧力と負圧開放室９０側から受ける圧力との差圧力が大きく）、そのため、通常時には縁切り背圧室９１から受ける流入通路１４側の一次圧力によって安定な閉弁状態が維持され、流入通路１４側が負圧化（低圧化）した時には負圧方向の大きな力を得て迅速に応答性よく開弁して、空気導入通路２１から空気をメーン弁室９３に導入して縁切り動作を行い得る。
【００５６】
同様に、ダイアフラム８２側も弁孔９５ｂ側から受ける圧力の受圧面積よりも排水背圧室１０１側からの圧力を受ける受圧面積が遥かに大きいので（弁孔９５ｂ側から受ける圧力と排水背圧室１０１側から受ける圧力との差圧力が大きくなるので）、通常時には排水背圧室１０１から受ける流入通路１４側の一次圧力によって安定な閉弁状態が維持され、流入通路１４側が負圧化（低圧化）した時には負圧方向の大きな力を得て迅速に応答性よく開弁して、流出通路１５から逆流してくる汚水を排水通路１０５から排水することが可能である。
【００５７】
さらに、第４の実施形態例では、空気導入通路２１は負圧開放室９０に直接的に連通し、排水通路１０５と同様にメーン導入通路４４から流出通路１５に至る直線状の流路に沿って下方（直線状の流路の下流側）に向けて延設されている。この構成としたことにより、図１に示すように空気導入通路２１が横方向に突き出ないため、装置の小型化が一層図れるものとなる。
【００５８】
なお、図４において、第１の逆止弁６７の筒軸７２の下部は板部１３５が円周等間隔に形成された羽根状の形態と成しているため、その板部１３５間の間隔すきまを利用してメーン弁室９３と弁孔９５ａとの連通が達成されている。また、カバー部材８３ａ、８３ｂの上部側は厚肉に形成され、その壁部内に背圧室９１、１０１に連通する連通路１３４ａ、１３４ｂが形成されており、連通路１３４ａによって一次圧連通通路１０７と負圧開放室９０とが連通され、連通路１３４ｂによって一次圧連通通路１０７と排水背圧室１０１とが連通されている。
【００５９】
また、凹部７９の底壁からは弁座８４の外側を間隔を介して囲むリング状の支持凸部１３２ａが突き出し形成されている。この支持凸部１３２ａの突き出し高さは弁座８４の突き出し高さとほぼ同じ高さとなっており、縁切り弁８９の閉弁状態時にダイアフラム８１を弁座８４の外側で受け止め支持するものである。同様に排水弁９９側にも凹部８０の底壁から支持凸部１３２ｂが突き出し形成され、排水弁９９の閉弁状態時にダイアフラム８２を弁座９４の外側で受け止め支持する。
【００６０】
また、図４に示す例では、逆止弁６７、６８、１１０の弁座（６５、６１等）は弁板７６側に形成されているが、図１〜図３に示されているように弁板が当接する相手側に形成してもよく、図１、図３に示されるように、逆止弁１１０を除去した構成としてもよい。
【００６１】
この第４の実施形態例においても、上記したこの実施形態例の特有の効果の他に、前記第１の実施形態例と同様な効果を奏することはいうまでもない。
【００６２】
図６は本発明に係る逆流防止装置５０の第５の実施形態例を示す。この第５の実施形態例の逆流防止装置５０は、排水弁９９を含む排水機構（排水手段）を有しない構成としたものであり、それ以外の構成は前記第１の実施形態例の逆流防止装置５０と同じであるので、その構成の重複説明は省略する。この第５の実施形態例の逆流防止装置５０も前記第１の実施形態例の逆流防止装置５０と同様に図５に示されるような給湯システムに組み込まれて使用される。なお、この第５実施形態例においても、縁切り室９２および縁切り弁８９の構成は図４に示す第４の実施形態例と同様な構成とすることも可能である。
【００６３】
ところで、家庭内の浴槽１の設置場所は様々であり、図５に示されるように、浴槽１が逆流防止装置５０よりも低位置に設置されている場合は、給水源側の一次圧が低圧化しても、前記のように縁切り弁８９によりメーン弁室９３が大気開放されることにより逆流は防止されるので、排水弁９９を取り除いた上記第２の実施形態例の逆流防止装置５０を給湯システムに組み込んでも、特に問題は生じない。
【００６４】
しかしながら、図７に示されるように、浴槽１が逆流防止装置５０よりも高い位置に設置された場合（例えば浴槽１が家屋の２階に設置され、器具（器具ケース３９）が１階に設置され、その間に逆流防止装置５０が配置されるような場合）は、逆流防止装置５０の縁切り弁８９により縁切りされても（メーン弁室９３が大気開放されても）、浴槽１側の水頭圧が大きいために逆止弁６７、６８が正常に動作しない場合には、逆流を防止することはできなくなる。このような場合、第１〜第４実施形態例の逆流防止装置５０のように、排水弁９９を有していれば、その逆流した水を排水するので、メーン弁室９３側に逆流の汚水が入り込むことはないが、図６に示す第５の実施形態例の逆流防止装置５０を使用した場合は、排水弁９９が設けられていないので、逆止弁６７、６８が正常に動作しない場合には、逆流を防止することはできなくなる。
【００６５】
図７は上記第５実施形態例の逆流防止装置５０を浴槽１が高位の位置に設置されている給湯システムに組み込み使用した場合においても、逆流を防止することが可能なシステム構成の実施形態例を示す。この図７の給湯システムにおいて、図６に示された構成の逆流防止装置５０が装備され、この逆流防止装置５０よりも高位の位置に浴槽１が設置されている。なお、逆流防止装置５０はその流入通路形成筒部４５を分岐管７に、流出通路形成筒部７８を落し込み管８にそれぞれ接続することにより給湯システムに組み込まれる。
【００６６】
図７に示す給湯システムにおいて特徴的なことは、給湯装置としての給湯器２から浴槽１に湯を供給する通路の落し込み管８に排水装置１１２が外付け配置されていることである。図８はこの排水装置１１２の一構成例を模式的に示すもので、バルブハウジング１１４の内部空間はダイアフラム１１７によって弁室１１５と背圧室１１６とに区分され、弁室１１５内にはダイアフラム１１７の中央部に基端部が固定された弁体１１８が配置されている。
【００６７】
弁体１１８の先端側には弁板１１９が設けられており、この弁板１１９と対向するバルブハウジング１１４の壁部に弁座１２５が形成されている。この弁座１２５の弁孔に通じる逆流流入通路１２１は筒部１２２の筒孔によって形成され、筒部１２２が連通管１１３を介して落し込み管８に連通接続されている。なお、弁体１１８の基端の板部１２６とそれに対向するバルブハウジング１１４の壁面との間には弁体１１８を開弁方向に付勢する弁ばね１２０が配置されている。また、弁室１１５の下部には筒部１２３が下向きに突出形成され、この筒部１２３の筒孔は排水通路１２４と成している。
【００６８】
背圧室１１６側のバルブハウジング１１４の壁面に突設された筒部１２７には一次圧供給管９が接続されて背圧室１１６内に給水源の一次圧（水道圧）が印加され、一次圧の低下のない通常時はその一次圧によってダイアフラム１１７は弁ばね１２０の付勢力に抗して弁座１２５側に撓み、弁板１１９が弁座１２５に圧接することで、閉弁状態を維持する。その一方において、断水等により一次圧が低下したときには背圧室１１６の圧力が低下することで、弁ばね１２０の付勢力および逆流流入通路１２１側に加わる二次圧力による開弁方向の力が閉弁方向の力に打ち勝ってダイアフラム１１７は開弁方向に変形する結果、弁板１１９は弁座１２５から離れて開弁し、浴槽１側から落し込み管８側へ逆流した汚水は連通管１１３から弁室１１５に入り込み、排水通路１２４を通して排水される。そのため、汚水が大気開放状態にある逆流防止装置５０まで逆流することはなく、汚水が分岐管７を介して給湯管６側に入り込むということは確実に防止される。
【００６９】
しかも、排水装置１１２側で排水動作を行い、逆流防止装置５０側でメーン弁室９３の大気開放（縁切り）を行なうという如く、排水動作と縁切り動作とが別個独立に分離して行なわれるので、この縁切りのための空気導入の通路と排水の通路を兼用した場合に生じる前記従来の問題の発生はなく、縁切りと排水の動作を迅速、確実に行なうことが可能となる。
【００７０】
なお、本発明は上記の各実施形態例に限定されることなく様々な実施の形態を採り得るものである。例えば、排水装置１１２はダイアフラム応動弁の構成としたが、逆流、あるいは一次圧の低下を検出して開弁する弁機構を備えているものであれば他の弁構成のものであってもよい。ただ、この実施形態例のようにダイアフラム応動弁の構成とした場合には、停電の場合であっても、それに影響を受けずに逆流汚水の排水動作を確実に行ない得るので好都合である。
【００７１】
また、前記第４の実施形態例においては、縁切り室９２と排水室１０２は同一構成となし、縁切り弁８９と排水弁９９も同一構成としたが、これら縁切り側と排水側の室の構成や、弁の構成は必ずしも同一構成としなくてもよい。また、第１〜第３実施形態例においても、縁切り側と排水側の室の構成や、弁の構成は同一構成としてもよいし、必ずしも同一構成としなくてもよい。
【００７２】
また、上記実施形態例では、逆流防止装置５０は給湯システムに組み込まれて使用されているが、本発明の逆流防止装置は給湯システム以外の流体の流通路に逆流を防止する装置として装備することが可能である。
【００７３】
【発明の効果】
縁切り弁と排水弁を共に備えた本発明の逆流防止装置およびその逆流防止装置を備えた給湯システムによれば、メーン制御弁の開、閉の何れの弁駆動動作状態にもかかわらず、給水側の一次圧を利用して縁切り弁と排水弁を共に閉弁状態に維持し、また、一次圧が低圧化（負圧化）した時にはその圧力低下を縁切り弁と排水弁に作用させて縁切り弁と排水弁とをともに開弁して縁切りと逆流した流体（水）の排水を別個独立に行なう構成とした。そのため、一次圧をそのまま縁切り弁と排水弁の弁駆動源として利用でき、装置構成を簡易化、小型化、低コスト化できると共に、停電等の電気系統の故障に影響を受けずに縁切りと排水の動作を確実に行なうことができ、装置動作の信頼性を高めることができるものである。
【００７４】
特に、空気導入通路を直接的に負圧開放室に連通し、負圧開放室は縁切り弁の弁孔のみを介してメーン弁室に連通する構成とした発明にあっては、縁切り弁のダイアフラムが受ける縁切り背圧室側からの圧力の受圧面積を弁孔側から受ける圧力の受圧面積よりも遥かに大きくできるので、当該ダイアフラムが受ける縁切り背圧室側からの圧力と弁孔側から受ける圧力との差圧力を大きくできる。これにより、通常時には縁切り背圧室側からの一次圧力により大きな閉弁力を得て縁切り弁の閉弁状態を確実安定に維持し、給水側の一次圧が低下（負圧化）した時には縁切り背圧室側から大きな負圧方向の力を得て、縁切り弁の開弁動作（縁切り動作）を迅速に（応答性よく）行い、流出通路側からの汚水の逆流を確実に防止できるので、逆流防止の信頼性を十分に高めることができる。
【００７５】
また、縁切り弁と排水弁のうち、縁切り弁のみを備えた本発明の逆流防止装置およびその逆流防止装置を備えた給湯システムにおいても、メーン制御弁の開、閉の何れの弁駆動動作状態にもかかわらず、給水側の一次圧を利用して縁切り弁を閉弁状態に維持し、また、一次圧が低圧化（負圧化）した時にはその圧力低下を縁切り弁に作用させて縁切り弁を開弁して縁切りを行なう構成としたので、一次圧をそのまま縁切り弁の弁駆動源として利用でき、装置構成を簡易化、小型化、低コスト化できると共に、停電等の電気系統の故障に影響を受けずに縁切りと排水の動作を確実に行なうことができ、装置動作の信頼性を高めることができる。
【００７６】
さらに、本発明の逆流防止装置は流入通路と流出通路にそれぞれ配管管路を接続するだけで、すなわち、２本の管路を接続するだけで給湯システムに組み込むことができるので、配管構成がすっきりと纏まり、配管接続作業も容易となる。
【００７７】
さらに、縁切り弁と排水弁を共に持つ本発明の逆流防止装置を備えた給湯システム、および縁切り弁のみを有する逆流防止装置と共に排水装置を別途備えた本発明の給湯システムによれば、一次圧が低下する異常時に、縁切り弁による縁切り動作と、排水弁（排水装置）による逆流水の排水動作とを別個独立の動作として行なうことができる。そのため、縁切りのための外部空気の導入の通路と逆流水の排水の通路とはそれぞれ専用の通路と成して、１つの通路が兼用使用されることによって生じる前記従来例の問題が解消され、縁切りと逆流排水の動作を迅速、確実に行なうことが可能となり、信頼性の高い装置およびシステムの提供が可能となる。
【００７８】
さらに本発明の逆流防止装置は通常時は一次圧を受けて縁切り弁、排水弁が閉弁されているので、空気導入通路や排水通路を介して外部から塵埃等の異物が装置内の流通路に侵入するのを防止できるという効果が得られるものである。
【図面の簡単な説明】
【図１】本発明に係る第１の実施形態例の逆流防止装置の構成説明図である。
【図２】本発明に係る第２の実施形態例の逆流防止装置の構成説明図である。
【図３】本発明に係る第３の実施形態例の逆流防止装置の構成説明図である。
【図４】本発明に係る第４の実施形態例の逆流防止装置の構成説明図である。
【図５】第１の実施形態例の逆流防止装置を組み込んだ給湯システムの構成説明図である。
【図６】本発明に係る第５の実施形態例の逆流防止装置の構成説明図である。
【図７】第５の実施形態例の逆流防止装置を組み込んだ給湯システムの構成説明図である。
【図８】図７の給湯システムに組み込まれている排水装置の模式構成図である。
【図９】特許文献１に開示されている従来の逆流防止装置の説明図である。
【図１０】図９の逆流防止装置を組み込んだ従来の給湯システムの説明図である。
【図１１】特許文献２に開示されている従来の逆流防止装置の説明図である。
【符号の説明】
２給湯器（給湯装置）
１４流入通路
１５流出通路
２１空気導入通路
４８パイロット電磁弁（メーン制御弁）
５０逆流防止装置
６７第１の逆止弁（逆流防止弁）
６８第２の逆止弁（逆流防止弁）
８９縁切り弁
９０負圧開放室
９１縁切り背圧室
９２縁切り室
９３メーン弁室
９９排水弁
１００排水処理室
１０１排水背圧室
１０２排水室
１０５排水通路
１０７一次圧連通通路
１１２排水装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backflow prevention device that allows water such as hot water or water to flow in the forward direction and blocks backflow, and a hot water supply system to a bathtub equipped with the device.
[0002]
[Background]
FIG. 9 shows the backflow prevention device disclosed in Patent Document 1, and FIG. 10 shows a hot water supply system (hot water filling system) to the bathtub 1 equipped with the backflow prevention device. This hot water supply system includes a hot water heater 2 as a hot water supply device, and water supplied through the water supply pipe 3 is converted into hot water by the combustion thermal power of the hot water supply burner 4 in the hot water supply heat exchanger 5, and the hot water is supplied through the hot water supply pipe 6 to a desired hot water supply position. To supply.
[0003]
A branch pipe 7 is connected to the hot water supply pipe 6, and the hot water supplied to the branch pipe 7 flows through the backflow prevention device 10 in the forward direction and is dropped into the bathtub 1 through the drop pipe 8. In FIG. 10, 11 is a flow sensor, 12 is a solenoid valve, and 13 is a check valve.
[0004]
As shown in FIGS. 9 and 10, the branch pipe 7 is connected to the inflow passage 14 of the backflow prevention device 10, the drop pipe 8 is connected to the outflow passage 15, and the primary pressure is introduced to the primary pressure inlet 16. The outlet of the supply pipe 9 is connected. The inlet side of the primary pressure supply pipe 9 is connected to the water supply pipe 3, and the water pressure on the side of the water supply pipe 3 is applied to the primary pressure inlet 16 as the primary pressure.
[0005]
During the operation of dropping hot water from the water heater 2 into the bathtub 1, the primary pressure from the primary pressure supply pipe 9 is received, the piston 17 moves to the left in the figure, and the valve 18 abuts against the wall surface 19 so that air The air introduction passage 21 of the introduction pipe 20 is closed (communication between the passages 14 and 15 and the air introduction passage 21 is blocked). In this state, hot water supplied from the branch pipe 7 passes through the outflow passage 15 from the inflow passage 14. It enters the drop tube 8 and is dropped into the bathtub 1. In this state, for example, when the water supply pipe 3 side becomes negative pressure due to water breakage or the like (the pressure on the water supply pipe 3 side is lower than the pressure on the dropping pipe 8 side), the piston 17 moves to the right and moves to the right. In this state, air enters from the air introduction passage 21 and opens the inflow passage 14 and the outflow passage 15 to atmospheric pressure. Thus, even if an abnormality occurs in the check valve 13 and the backflow prevention function by the check valve 13 does not work normally, sewage from the bathtub 1 side enters the water supply pipe 3 side via the branch pipe 7. It is intended to prevent backflow. In addition, the air introduction pipe 20 is provided in the downward direction, and even if the sewage on the bathtub 1 side flows backward, the sewage is drained from the air introduction passage 21 and tries to prevent the sewage from flowing to the inflow passage 14 side. Is.
[0006]
FIG. 11 shows a backflow prevention device 10 shown in Patent Document 2, and this device is also used in a hot water supply system (the check valve 13 is removed) as shown in FIG. FIG. 11 shows an operating state in which hot water of the water heater is dropped into the bathtub, and the hot water that has entered the inflow passage 14 from the water heater side opens the check valves 22 and 23 by the primary pressure of the inflow and opens the valve chamber 24. As a result, hot water is dropped from the outflow passage 15 into the bathtub via the drop pipe 8 (see FIG. 10). At this time, since the primary pressure is supplied to the back pressure chamber 26 of the diaphragm responsive valve 25 from the inflow passage 14 side via the communication passage 27, the diaphragm 28 is bent and deformed to the valve chamber 24 side, and is moved accordingly. The valve body 29 moves in the bending deformation direction, the valve plate 30 is brought into contact with the fixed valve body 31, and the communication between the air introduction passage 21 and the valve chamber 24 is maintained in a blocked state.
[0007]
On the other hand, if the inflow passage 14 side becomes negative pressure due to water breakage or the like, the check valves 22 and 23 are closed to prevent backflow, but even if both the check valves 22 and 23 become abnormal, the backflow prevention operation is normal. Even if the pressure does not work, the pressure in the back pressure chamber 26 decreases due to the negative pressure, so that the diaphragm 28 is displaced toward the air introduction passage 21 and the movable valve element 29 is also displaced in the same direction. As a result, the valve plate 30 is separated from the fixed valve body 31 and air is introduced from the air introduction passage 21 to the valve chamber 24. As a result, the valve chamber 24 is opened to the atmosphere to prevent backflow, and the air introduction passage 21 Therefore, the sewage flowing back to the valve chamber 24 is drained from the air introduction passage 21, and the sewage can be prevented from entering the inflow passage 14 side.
[0008]
[Patent Document 1]
JP 2000-304144 A
[Patent Document 2]
Japanese Patent Laid-Open No. 7-224958
[0009]
[Problems to be solved by the invention]
However, since the backflow prevention device disclosed in Patent Document 1 has a configuration in which three pipe lines of the branch pipe 7, the drop pipe 8, and the primary pressure supply pipe 9 are connected, the pipe connection work is difficult. There is a problem that the piping configuration becomes complicated. Further, the air introduction passage 21 also functions as a drainage passage. As a result, for example, when the water breakage occurs in the middle of filling the bathtub 1, the check valve 13 has an abnormality. When the sewage on the bathtub 1 side flows backward, even if the piston 17 moves in the valve opening direction and tries to communicate the passages 14 and 15 in the apparatus with the air introduction passage 21, the fluid (water) in the apparatus introduces air. In order to be discharged from the passage 21, the direction in which the drainage flows and the direction in which the air enters from the outside are opposite to each other, and occupy the entire cross-sectional area of the air introduction passage 21, against the drainage that flows out. Therefore, it becomes difficult for air to enter the air introduction passage 21 from the outside. Therefore, there is a risk that the timing of opening the passage in the apparatus to the atmosphere is delayed, the sewage on the bathtub 1 side enters from the drop pipe 8 side to the branch pipe 7 side, and the sewage enters the water supply pipe 3 side. It becomes an upper problem.
[0010]
Further, the backflow prevention device disclosed in Patent Document 2 has the same problem because the air introduction passage 21 also serves as a drainage passage. In addition, since the device of Patent Document 2 has a complicated structure in which a plurality of device components such as the check valve 22 and the fixed valve body 31 are accommodated and deployed in the valve chamber 24, device manufacture is not easy, There is a problem that the apparatus becomes large and the apparatus cost increases. Further, in the apparatus shown in Patent Document 2, the valve on the upstream side of the pipe connected to the inflow passage 14 (for example, the electromagnetic valve 12 as shown in FIG. 10) is in a hot water supply standby state. The pressure on the inflow passage 14 side (the pressure in the back pressure chamber 26) and the pressure in the valve chamber 24 are almost the same pressure, so that the movable valve element 29 is separated from the fixed valve element 31 by the biasing force of the spring 32. Therefore, there is a problem that the air introduction passage 21 and the valve chamber 24 are kept in communication with each other, and foreign matters such as dust enter the valve chamber 24 from the outside through the air introduction passage 21.
[0011]
The present invention has been made in order to solve the above-described conventional problems. The purpose of the present invention is to provide hot water to a bathtub or the like simply by connecting a pipe to the inflow passage and the outflow passage (by simply connecting two pipes). It can be installed in the hot water supply system to supply dust, so that dust does not enter the device (valve chamber) when hot water is on standby, and if the primary pressure (water supply side pressure) drops, such as during a water outage It is possible to reliably open the valve chamber to the atmosphere to prevent backflow from the outflow passage side, and to provide a backflow prevention device capable of simplifying the device configuration, reducing the size and reducing the cost, and a hot water supply system equipped with the device. It is to provide.
[0012]
[Means for Solving the Invention]
In order to achieve the above object, the present invention provides means for solving the problems with the following configuration. That is, in the first invention, an inflow passage, a main introduction passage for introducing an inflow fluid from the inflow passage into the main valve chamber, and an outlet side of the main valve chamber communicate with the inflow fluid in the apparatus. A main control valve for introducing an inflow fluid from the inflow passage by opening the valve and shutting off the introduction of the inflow fluid by closing the valve at the inlet portion of the main introduction passage. The inlet side and the outlet side of the chamber are each provided with a backflow prevention valve that opens by the inflow forward pressure of the inflowing fluid and prevents the backflow by closing the valve. The edge cutting chamber is divided into an edge cutting back pressure chamber and a negative pressure release chamber communicating with the main valve chamber via a diaphragm, and an air introduction passage for introducing external air to the negative pressure release chamber via the edge cut valve. Communicated and said rim The back pressure chamber communicates with the inflow passage through a primary pressure communication passage formed in the apparatus, and the edge cut valve always receives the primary pressure on the inflow passage side applied to the edge cut back pressure chamber. The diaphragm is bent and deformed to the negative pressure release chamber side to close the edge cut-off valve to cut off the communication between the air introduction passage and the main valve chamber, and when the inflow passage is reduced in pressure, the diaphragm is reduced in pressure. Is received from the edge-cutting back pressure chamber side, bent to the edge-cutting back pressure chamber side, and deformed to return, thereby opening the edge-cutting valve to connect the air introduction passage and the main valve chamber to The structure is a diaphragm responsive valve that opens to the atmosphere as a means to solve the problem.
[0013]
The second aspect of the invention includes an inflow passage in the apparatus, a main introduction passage for introducing the inflow fluid from the inflow passage into the main valve chamber, and the outlet fluid in communication with the outlet side of the main valve chamber. A main control valve for introducing an inflow fluid from the inflow passage by opening the valve and shutting off the introduction of the inflow fluid by closing the valve at the inlet portion of the main introduction passage. The inlet side and outlet side of the chamber are each provided with a backflow prevention valve that opens by the inflow forward pressure of the inflowing fluid and prevents the backflow by closing the valve. The edge cutting chamber is divided into an edge cutting back pressure chamber and a negative pressure release chamber communicating with the main valve chamber through a diaphragm, and an air introduction passage for introducing external air is cut into the negative pressure release chamber. Communicated through a valve, The edge cut back pressure chamber communicates with the inflow passage through a primary pressure communication passage formed in the apparatus, and the edge cut valve always applies a primary pressure on the inflow passage side applied to the edge cut back pressure chamber. In response, the diaphragm is bent and deformed to the negative pressure release chamber side to close the edge cut valve to cut off the communication between the air introduction passage and the main valve chamber, and when the inflow passage is reduced in pressure, the diaphragm The main valve chamber is opened by receiving pressure from the side of the edge-cutting back pressure chamber to bend and returning to the edge-cutting back pressure chamber, thereby opening the edge-cutting valve and communicating the air introduction passage with the main valve chamber. The drainage chamber is divided into a drainage back pressure chamber and a drainage treatment chamber communicating with the outflow passage via a diaphragm, and the drainage treatment chamber is drained via a drainage valve. aisle The drainage back pressure chamber is communicated with the inflow passage through a primary pressure communication passage formed in the apparatus, and the drain valve is on the side of the inflow passage that is normally applied to the drain back pressure chamber. By receiving the primary pressure, the diaphragm is bent and deformed toward the waste water treatment chamber to close the drain valve, thereby shutting off the communication between the drain passage and the outflow passage, and when the inflow passage is reduced in pressure, the diaphragm A configuration in which a diaphragm responsive valve that receives pressure from the drain back pressure chamber side to bend and returns to the drain back pressure chamber side and opens the drain valve to communicate the outflow passage and the drain passage by receiving pressure corresponding to the low pressure is provided. As a means to solve the problem.
[0014]
Further, the third invention comprises the structure of the second invention, wherein the flow passage passing through the main introduction passage, the main valve chamber, and the outflow passage in turn is a straight flow passage, The edge cutting chamber and the drainage chamber are formed separately in the outer peripheral side region of the main valve chamber, and the outlet side of the inflow passage is connected to the passage leading to the main introduction passage through the main control valve, the edge cutting back pressure chamber and the drainage back. An abnormality that is communicated with the primary pressure communication passage led to the pressure chamber, and that always closes the edge cutoff valve and the drain valve by the primary pressure on the inflow passage side without depending on the opening and closing of the main control valve, and the primary pressure is lowered. Only in some cases, the edge cut valve and the drain valve are opened depending on the pressure drop in the edge cut back pressure chamber and the drain back pressure chamber.
[0015]
Further, the fourth invention comprises the configuration of the third invention, wherein the edge cutting chamber and the drainage chamber are formed in the same shape, and the air introduction passage and the drainage chamber communicated with the edge cutting back pressure chamber of the edge cutting chamber. Both drainage passages communicating with the wastewater treatment chamber are characterized by extending along the straight flow path from the main introduction passage to the outflow passage toward the downstream side of the flow passage.
[0016]
Further, the fifth invention is the one provided with the configuration of the first, second, third or fourth invention, wherein the air introduction passage communicates with the negative pressure release chamber via an edge cut valve. The air introduction passage is directly communicated with the negative pressure release chamber, and the negative pressure release chamber is communicated with the main valve chamber only through the valve hole of the edge cut valve.
[0017]
Furthermore, the sixth invention relates to a hot water supply system, and this hot water supply system is provided with the backflow prevention device of the second, third, fourth or fifth invention in the middle of a passage for supplying hot water from the hot water supply device to the bathtub. It is provided.
[0018]
Furthermore, the seventh invention relates to a hot water supply system, and this hot water supply system is provided with the backflow prevention device of the first invention in the middle of a passage for supplying hot water from the hot water supply device to the bathtub. A drainage device for draining the fluid that has flowed back from the bathtub side is externally installed in the passage on the downstream side.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the following description, the above-described conventional example is included, common constituent parts are denoted by common reference numerals, and redundant description thereof is omitted or omitted.
[0020]
FIG. 1 shows a first embodiment of a backflow prevention device according to the present invention, and FIG. 5 shows one embodiment of a hot water supply system equipped with the backflow prevention device 50. As shown in FIG. 1, the backflow prevention device 50 of this embodiment is fitted and attached to the upper side of a cylindrical main body outer body 51, and the base end side of the inflow side body 42 is fitted inside the inflow side body 42. The introduction passage forming member 43 is inserted. In the description of this embodiment, the terms “upper” and “lower” are used in the state of the apparatus posture of FIG. 1, and do not necessarily match the upper and lower concepts when the apparatus is actually used.
[0021]
The inflow side body 42 has an up and down cylinder wall and an inflow passage forming cylinder part 45 extending and branching laterally from the upper side of the up and down cylinder wall. The hole functions as the inflow passage 14. A flow sensor 46 for detecting the flow rate is disposed in the inflow passage 14 as necessary. A main control valve is provided on the upper end side of the vertical cylindrical wall of the inflow side body 42. The main control valve may be any valve as long as it has a function of controlling and opening the opening of the valve seat 47 at the upper end of the main introduction passage 44 formed by the cylindrical hole of the introduction passage forming member 43. However, in the example of FIG. 1, the pilot solenoid valve 48 is used as a main control valve, and is fixed to the upper end of the inflow side body 42 with a screw 52.
[0022]
Since the configuration of this type of pilot solenoid valve is well known, the description thereof will be simplified. However, the valve element 53 is supported by the diaphragm 54 on the lower end side of the sliding rod 49, and the spring 56 is normally provided. In response to the downward biasing force, the valve plate 57 of the valve body 53 contacts the valve seat 47 and closes the main introduction passage 44. When the solenoid coil 55 is driven, the sliding rod 49 moves upward against the urging force of the spring 56 and moves the valve body 53 upward to open the opening of the valve seat 47 on the upper end side of the main introduction passage 44. It opens and opens.
[0023]
A flange 127 is formed on the outer periphery of the inflow side body 42, and the flange 127 is engaged with and positioned by the upper end of the main body external body 51. A locking groove 128 is provided around the outer peripheral surface of the inflow side body 42. A pair of pin holes penetrating the inside of the locking groove 128 at both the left and right positions are formed in the main body outer body 51 side in parallel, and a U-shaped locking pin 129 is inserted into the pin hole from the outside. Thus, the locking pin 129 is inserted through the locking groove 128, and the inflow side body 42 is locked to the main body external body 51 so as to freely swing and move. Of course, the inflow-side body 42 and the main body external body 51 may be fixed using appropriate fastening means such as bolts. A stepped portion 58 projecting inward is formed on the inner wall of the cylindrical hole of the main body outer body 51, and the lower end of the introduction passage forming member 43 is locked to the upper surface of the stepped portion 58 so that the introduction passage forming member 43 is connected to the main body outer body. 51. A valve seat 65 protruding downward is formed at the lower end of the main introduction passage 44. In addition, an O-ring is interposed at an appropriate position on the fitting surface between the inflow side body 42 and the main body outer body 51 and the fitting surface between the introduction passage forming member 43 and the main body outer body 51, thereby airtight fitting. Has been achieved.
[0024]
The cylindrical hole of the main body outer body 51 is provided with a stepped portion 59 that protrudes further inwardly at a position below the stepped portion 58, and is locked to the stepped portion 59 so that the valve seat forming cylindrical member 60 forms an introduction passage. It is arranged at the lower part of the member 43. A stepped portion 62 that protrudes inward is formed at the lower portion of the tube hole of the valve seat forming cylinder member 60, and a valve seat 61 that protrudes downward is formed at the lower end portion of the valve seat forming cylinder member 60. In addition, a through hole 63 is formed in the straight cylinder wall above the step portion 62, and a through hole 64 is also formed in the cylinder wall of the main body external body 51 facing the through hole 63. In addition, airtight means such as an O-ring is appropriately interposed between the fitting wall surfaces of the valve seat forming cylinder member 60 and the main body external body 51 to achieve airtight fitting.
[0025]
On the cylindrical wall surface of the valve seat forming cylindrical member 60, a step portion 66 is formed protruding further inward at a position lower than the step portion 59. A first backflow prevention valve is provided in the cylindrical hole space between the step portion 62 and the valve seat 65, and a second backflow prevention valve is provided in the cylindrical hole space between the step portion 66 and the valve seat 61. ing. When the water flows in the forward direction (in the direction from the top to the bottom in the figure), these backflow prevention valves open the valve by the water supply side pressure (primary side pressure), and the water supply side pressure becomes negative (downstream pressure ( Any valve may be used as long as it has a function of closing the valve when the pressure is lower than the secondary side pressure) to prevent backflow. However, in the illustrated example, a check valve is used together. Yes. That is, the first check valve 67 is used as the first check valve and the second check valve 68 is used as the second check valve. These check valves 67 and 68 have the same configuration.
[0026]
These check valves 67 and 68 are configured to have a support base 69 and a valve body 70, and the support base 69 is provided with a cylindrical shaft 72 protruding upward at the center of the base plate 71. A plurality of through holes 73 are formed, and a center rod 74 of the valve body 70 is slidably inserted into the center hole of the cylindrical shaft 72. A flange plate portion 75 is formed at the upper end of the center rod 74, and a valve plate 76 is fixed to the upper surface of the flange plate portion 75 with screws. A compression-deformed spring 77 is interposed between the lower surface of the base plate 71 and the flange plate portion 75. The support base 69 of the first check valve 67 is disposed on the stepped portion 62, and the valve plate 76 contacts the valve seat 65 by receiving the upward biasing force of the spring 77 to open the valve seat 65 (valve hole). Is closed. Similarly, the support base 69 of the second check valve 68 is disposed on the step portion 66, and the valve plate 76 abuts against the valve seat 61 in response to the upward biasing force of the spring 77 and opens the valve seat 61 ( The valve hole) is closed.
[0027]
An outflow passage forming cylinder portion 78 is inserted and fixed in a cylindrical hole on the lower side of the main body outer body 51, and a central hole of the outflow passage formation cylinder portion 78 forms the outflow passage 15. This outflow passage forming cylinder portion 78 is also inserted and attached to the main body external body 51 in an airtight manner using an airtight means such as an O-ring as appropriate. In the example shown in the drawing, the locking groove 130 and the locking pin 131 are similar to the locking structure of the inflow side body 42 and the main body external body 51 using the locking groove 128 and the locking pin 129. Due to the locking configuration, the outflow passage forming cylinder portion 78 is locked to the main body external body 51 so as to freely swing and move.
[0028]
Concave portions 79 and 80 are provided at positions where the outer peripheral surface of the main body external body 51 is separated, in the illustrated example, at positions opposite to the left and right sides. Diaphragms 81 and 82 are respectively attached to the outer surfaces of the main body external body 51 on the opening side of the recesses 79 and 80. The recess 79 is airtightly covered by the diaphragm 81, and the recess 80 is airtightly covered by the diaphragm 82. It has been broken. The outside of the arrangement area of the diaphragms 81 and 82 is covered with a cover member 83 that is airtightly attached to the outside of the main body external body 51 through the space.
[0029]
A valve seat 84 projecting toward the diaphragm 81 is provided in a ring shape on the surface of the central region of the recess 79. A region of the diaphragm 81 at a portion facing the valve seat 84 is formed thick and forms a valve portion 85, and a base end portion of the air introduction pipe 86 is airtightly attached to the central hole of the valve portion 85 using a mounting plate 87. It is fixed to. The front end side of the air introduction pipe 86 is fitted into the cylindrical portion 88 of the cover member 83 in an airtight manner via an O-ring, and the center hole of the air introduction pipe 86 forms the air introduction passage 21 and communicates with the outside.
[0030]
The valve seat 84 and the valve portion 85 facing the valve seat 84 function as an edge cut valve 89, and a space surrounded by the recess 79 and the diaphragm 81 on the outer side of the edge cut valve 89 forms a negative pressure release chamber 90. Further, the space surrounded by the diaphragm 81 and the cover member 83 forms an edge cutting back pressure chamber 91, and the edge cutting back pressure chamber 91 and the negative pressure release chamber 90 form an edge cutting chamber 92. That is, the edge cutting chamber 92 is divided into a negative pressure release chamber 90 and an edge cutting back pressure chamber 91 by the diaphragm 81.
[0031]
An inner space region of the valve seat forming cylinder member 60 is formed as a main valve chamber 93, an inlet of the main valve chamber 93 is opened and closed by a first check valve 67, and an outlet of the main valve chamber 93 is a second reverse valve. It is configured to be opened and closed by a stop valve 68. In this embodiment, the main introduction passage 44, the main valve chamber 93, and the outflow passage 15 form a continuous straight passage through the check valves 67 and 68. The main valve chamber 93 communicates with the negative pressure release chamber 90 through the through holes 63 and 64, and the air introduction passage 21 and the negative pressure release chamber 90 communicate with each other through the edge cut valve 89. The main valve chamber 93 communicates with the main valve chamber 89 via an edge cut valve 89.
[0032]
A valve seat 94 protruding outward (diaphragm 82 side) is provided on the wall portion of the main body external body 51 on the concave portion 80 side, and the portion of the diaphragm 82 facing the valve seat 94 is formed thick so that the valve portion The drainage valve 99 is formed by the valve seat 94 and the valve portion 96. The space of the recess 80 surrounded by the wall surface of the main body outer body 51 and the diaphragm 82 functions as the waste water treatment chamber 100, and the space surrounded by the diaphragm 82 and the cover member 83 functions as the drain back pressure chamber 101. . That is, the internal space of the cover member 83 surrounding the outside of the diaphragm 82 is formed as a drainage chamber 102, and the drainage chamber 102 is divided into a drainage treatment chamber 100 and a drainage back pressure chamber 101 by the diaphragm 82. Yes.
[0033]
The waste water treatment chamber 100 communicates with the outflow passage 15 via the valve hole 95 of the valve seat 94 and the through hole 73 of the second check valve 68. A spring receiving plate 97 is attached to an outer portion of the valve portion 96 of the diaphragm 82, and a compression spring 98 is interposed between the spring receiving plate 97 and the wall surface of the main body external body 51 (the bottom wall surface of the recess 80). Is arranged. The spring 98 acts on the valve portion 96 with a biasing force in a direction to open the valve hole 95. It should be noted that the diaphragm 81 and the diaphragm 82 may be separate bodies or a common integrated object.
[0034]
A cylindrical portion 103 is formed at the lower end of the main body external body 51 on the drain valve 99 side, and a water pipe 104 is fitted and attached to the cylindrical portion 103, and the tip of the water pipe 104 communicates with the outside, and an outflow passage. 15 is introduced into the wastewater treatment chamber 100 through the through-hole 73 and the valve hole 95 of the second check valve 68, and further to the outside through the drainage passage 105 of the water distribution pipe 104 from the wastewater treatment chamber 100. Consists of draining configuration.
[0035]
A flow passage 106 communicating with the inflow passage 14 is formed between the outer periphery of the introduction passage forming member 43 and the inner peripheral surface of the inflow side body 42 facing it. The upper side of the flow passage 106 forms a passage that connects the inflow passage 14 and the main introduction passage 44 through the valve portion of the pilot solenoid valve 48, and the passage toward the lower side of the flow passage 106 cuts off the inflow passage 14. The primary pressure communication passage 107 communicates with the pressure chamber 91 and the drainage back pressure chamber 101. The primary pressure communication passage 107 and the edge-cut back pressure chamber 91 communicate with each other through a through hole 108 provided in the main body external body 51, and the primary pressure communication passage 107 and the drain back pressure chamber 101 are provided in the main body external body 51. It communicates through the hole 109.
[0036]
The backflow prevention device 50 having the above configuration is used by being incorporated in a hot water supply system as shown in FIG. This hot water supply system has a function of dropping hot water produced by the hot water supply heat exchanger 5 into the bathtub 1 as in the hot water supply system shown in FIG. And the outflow passage forming cylinder portion 78 of the backflow prevention device 50 is connected to the drop pipe 8, so that the backflow prevention device 50 is incorporated into the hot water supply system. In the hot water supply system of the present embodiment, a recirculation circuit 33 is connected to the bathtub 1, and the hot water supplied from the dropping pipe 8 is dropped into the bathtub 1 through the recirculation circuit 33. are doing. Since a bath reheating apparatus including the recirculation circulation path 33 is well known, in brief, the circulation pump 37 is driven to draw the hot water from the bathtub 1 from the return pipe 34, and the recirculation heat exchanger 35 passes the recirculation heat exchanger 35. Circulate from the pipeline 36 to the bathtub 1. By detecting the flow of the circulating hot water, the reheating burner 38 is driven to burn, the hot water passing through the reheating heat exchanger 35 is heated by the combustion flame, and the temperature of the hot water in the bathtub 1 is raised. When the temperature reaches the set temperature of the bath, the circulation pump 37 is stopped to stop the chasing operation.
[0037]
Of course, as shown in FIG. 10, the backflow prevention device 50 according to the present embodiment may be configured such that hot water is supplied directly from the dropping pipe 8 to the bathtub 1 without providing the recirculation circuit 33. In FIG. 5, reference numeral 39 denotes an instrument case.
[0038]
Next, the operation of the backflow prevention device 50 will be described with reference to FIGS. When hot water is not dropped into the bathtub 1 from the hot water heater 2 side, the pilot solenoid valve 48 is closed, and the inlet of the main introduction passage 44 is closed by the valve plate 57. In this state, the inflow passage 14 is communicated with the edge-cut back pressure chamber 91 and the drain back pressure chamber 101 via the primary pressure communication passage 107, and the edge cut back pressure chamber 91 and the drain back pressure chamber 101 are connected to the water supply source side. Water pressure (tap pressure) is applied as a primary pressure, and on the side of the edge-cutting valve 89, the primary pressure is received and the diaphragm 81 is bent and deformed toward the valve seat 84, so that the valve portion 85 is pressed against (abuts) the valve seat 84. The edge cut valve 89 is closed. That is, the communication between the air introduction passage 21 and the negative pressure release chamber 90 (main valve chamber 93) is blocked. Similarly, the drain valve 99 also receives the primary pressure, the diaphragm 82 bends and deforms toward the valve seat 94 against the urging force of the spring 98, and the valve portion 96 presses against the valve seat 94 so that the drain valve 99 It is closed and the communication between the wastewater treatment chamber 100 (drainage passage 105) side and the outflow passage 15 side is blocked.
[0039]
When the pilot solenoid valve 48 is driven to open in this state, the valve plate 57 moves away from the valve seat 47 and opens, so that hot water entering from the inflow passage 14 is introduced into the main introduction passage 44. The Then, the first check valve 67 and the second check valve 68 are opened by the feed water pressure (primary pressure), and the hot water passes through the main valve chamber 93 and drops from the outflow passage 15 and enters the pipe 8. It is dropped into the bathtub 1 through the whirling circulation path 33. Even during the dropping of the hot water, the primary pressure is applied to the edge cut back pressure chamber 91 and the drain back pressure chamber 101, so that the edge cut valve 89 and the drain valve 99 are both kept closed.
[0040]
If an abnormality in which the primary pressure decreases during the dropping of the hot water, for example, water breakage occurs, the pressure (primary pressure) on the inflow passage 14 side becomes lower than the pressure (secondary pressure) on the outflow passage 15 side (negative pressure). Therefore, the hot water on the bathtub 1 side is attracted to the water supply pipe 3 side and tends to flow backward. At this time, the first check valve 67 and the second check valve 68 are closed to prevent backflow. For example, foreign matter is caught between the valve plate 76 and the corresponding valve seats 65 and 61. Even when the check valves 67 and 68 do not normally perform the backflow operation due to some abnormality such as the above, the backflow prevention device 50 of the present embodiment reliably prevents the backflow by the following operation.
[0041]
That is, since the edge-cut back pressure chamber 91 and the drain back pressure chamber 101 are communicated with the inflow passage 14, the pressure in the edge cut back pressure chamber 91 and the drain back pressure chamber 101 is reduced (negative pressure). That is, on the edge cutting valve 89 side, the pressure on the negative pressure release chamber 90 side becomes higher than the pressure on the edge cutting back pressure chamber 91, and the diaphragm 81 is elastically restored in a direction away from the valve seat 84. As a result of the restoring force, the edge cut valve 89 is opened (the valve portion 85 is separated from the valve seat 84), and external air is introduced from the air introduction passage 21 into the main valve chamber 93 through the negative pressure release chamber 90. The main valve chamber 93 is opened to the atmosphere, so that the so-called edge cutting between the outflow passage 15 side and the inflow passage 14 side is achieved, and the sewage on the outflow passage 15 side is reliably prevented from flowing back to the inflow passage 14 side. The
[0042]
In this manner, the edge cut valve 89 normally receives the primary pressure on the inflow passage 14 side applied to the edge cut back pressure chamber 91 and bends and deforms the diaphragm 81 toward the negative pressure release chamber 90 side to close the edge cut valve and air. The communication between the introduction passage 21 and the main valve chamber 93 is cut off, and when the inflow passage 14 is reduced in pressure, the diaphragm 81 receives a pressure corresponding to the reduced pressure from the edge-cutting back pressure chamber 91 side and the edge-cutting back pressure chamber 91 side. The diaphragm valve is configured as a diaphragm responsive valve that opens the edge cut valve by causing the air introduction passage 21 and the main valve chamber 93 to communicate with each other, thereby opening the main valve chamber 93 to the atmosphere.
[0043]
On the other hand, on the drain valve 99 side, the drain back pressure chamber 101 is reduced in pressure, so that the valve opening direction force due to the biasing force of the spring 98 and the valve opening direction force due to the secondary pressure from the outflow passage 15 side are closed. Overcoming the force in the valve direction, the diaphragm 82 is elastically deformed and opened in the direction in which the valve portion 96 moves away from the valve seat 94. Therefore, even if sewage on the bathtub 1 side flows backward, Since the water enters the drainage passage 105 from the valve hole 95 through the wastewater treatment chamber 100 and is drained to the outside, the sewage is reliably prevented from flowing back to the inflow passage 14 side.
[0044]
In this way, the drain valve 99 normally receives the primary pressure on the inflow passage 14 side applied to the drain back pressure chamber 101 and bends and deforms the diaphragm 82 to the drain treatment chamber 100 side to close the drain valve to thereby drain the drain passage. When the inflow passage 14 is depressurized, the diaphragm 82 receives a pressure corresponding to the low pressure from the drainage back pressure chamber 101 side and returns to the drainage back pressure chamber 101 side. By being deformed, it is configured as a diaphragm responsive valve that opens the drain valve and allows the outlet passage 15 and the drain passage 105 to communicate with each other.
[0045]
According to the backflow prevention device 50 of the present embodiment, when it is incorporated into the hot water supply system, it is only necessary to connect the two pipes of the branch pipe 7 and the drop pipe 8 as shown in FIG. Compared to the one connected to the three pipes of the branch pipe 7, the drop pipe 8 and the primary pressure supply pipe 9, not only the installation work into the hot water supply system is facilitated but also the pipe construction is simplified. It becomes possible to do.
[0046]
Regardless of the operating state of the pilot solenoid valve 48 (regardless of whether the pilot solenoid valve 48 is open or closed), the primary pressure on the inflow passage 14 side passes through the primary pressure communication passage 107. Therefore, as long as there is no abnormality in which the pressure in the inflow passage 14 is reduced, the edge cut valve 89 and the drain valve 99 use the primary pressure. The foreign matter such as external dust can be prevented from entering the internal hot water circulation passage including the main valve chamber 93 through the air introduction passage 21 and the drain passage 105. However, problems such as biting into the valve seats 65 and 61 corresponding to the valve plates 76 of the check valves 67 and 68 can be prevented.
[0047]
Further, when an abnormality occurs in which the pressure in the inflow passage 14 is reduced, both the edge cut valve 89 and the drain valve 99 are opened using the negative pressure of the edge cut back pressure chamber 91 and the drain back pressure chamber 101, and the edge cut valve 89 Even if the main valve chamber 93 is opened to the atmosphere by opening the valve to cut the edge and the sewage flows backward, the sewage is drained from the drain valve 99, so that the sewage is reliably prevented from flowing back to the inflow passage 14 side. Can do. In this way, both the edge cut valve 89 and the drain valve 99 communicate the back pressure chamber side with the inflow passage 14, and the valve is closed by the primary pressure when normal, and the lower pressure of the primary pressure is used when the primary pressure decreases. Since the primary pressure on the inflow passage 14 side is used as an opening / closing drive source for the edge valve 89 and the drain valve 99, the device configuration is simplified, the device is downsized, and the device cost is reduced. In addition, since there is no use of electrical parts such as a solenoid valve, the edge cutting and draining operations can be performed reliably without being affected by a power failure, so the reliability is very high.
[0048]
In particular, the backflow prevention device 50 according to the present embodiment forms the air introduction passage 21 and the drainage passage 105 as separate dedicated passages, so that when the inflow passage 14 side is reduced in pressure (negative pressure), the flow is prevented. Since the air introduction flow and the drainage flow that are opposite in direction do not cross each other and interfere with each other, the edge cutting operation and the drainage operation can be performed quickly with good response. It plays.
[0049]
FIG. 2 and FIG. 3 are diagrams showing modifications of the backflow prevention device 50 according to the present embodiment as second and third embodiments. As shown in FIG. 2, the second embodiment as a first modification is that an additional check valve 110 is provided as a backflow prevention valve in the outflow passage 15 of the outflow passage forming cylinder portion 78. is there. Thus, by adding the check valve 110 and arranging the three-stage check valves 67, 68, 110, the effect of preventing the backflow can be further enhanced.
[0050]
As shown in FIG. 3, in the third embodiment as a second modification, a compression spring 111 is arranged between the valve portion 96 and the cover member 83 in the drain back pressure chamber 101, and Instead, the spring 98 shown in FIG. 1 is removed, and this spring 111 applies a force in the valve closing direction that urges the valve portion 96 toward the valve seat 94. With this configuration, the drain valve 99 is closed by the urging force of the primary pressure on the inflow passage 14 side and the spring 111 when the inflow passage 14 side is not negatively pressured (lower pressure), and the inflow passage 14 side becomes negative pressure. When abnormal, the negative pressure of the primary pressure overcomes the urging force of the spring 111 and opens. Configurations and effects other than those of the first and second modifications are the same as the configuration and effects shown in FIG. The devices of the second and third embodiments are also used by being incorporated into various hot water supply systems in the same manner as the devices of the first embodiment.
[0051]
FIG. 4 shows a fourth embodiment of the backflow prevention device 50 according to the present invention. The apparatus according to the fourth embodiment is also used by being incorporated in various hot water supply systems in the same manner as the apparatuses according to the first to third embodiments. The difference from the third embodiment is that the edge cutting chamber 92 and the drainage chamber 102 are formed in the same shape to further reduce the size of the device and simplify the device configuration, and further, the responsiveness of the valve operation of the edge cutting valve 89. The other configurations are the same as those of the first to third embodiments, and a duplicate description of the common configuration is omitted.
[0052]
In the fourth embodiment, the positions of the concave portion 79 and the concave portion 80 formed on the outer peripheral surface of the main body external body 51 are shifted in the vertical direction, and the concave portion 80 is formed at a position below the concave portion 79. The edge cut valve 89 formed on the concave portion 79 side and the drain valve 99 formed on the concave portion 80 side have the same configuration. That is, the recess 79 and the recess 80 have the same shape, the negative pressure release chamber 90 has the same shape as the waste water treatment chamber 100, the edge-cut back pressure chamber 91 and the drain back pressure chamber 101 have the same shape, and the valve seat 84. Is the same shape as the valve seat 94. Further, the valve hole 95 a of the edge cut valve 89 has the same shape as the valve hole 95 b of the drain valve 99. The diaphragm 81 and the diaphragm 82 have the same shape, and the cover member 83a and the cover member 83b have the same shape.
[0053]
Thus, by making the edge cut valve 89 and the drain valve 99 have the same shape (same structure), the diaphragm 81 and the diaphragm 82 can use the same parts, and the cover member 83a and the cover member 83b can also use the same parts. Thus, the parts management becomes easy, and the concave portions 79 and the concave portions 80 have the same shape. Therefore, the concave portions 79 and 80 can be easily formed by a mold or the like, and the productivity of the apparatus can be increased.
[0054]
In the fourth embodiment, the diaphragms 81 and 82 have their outer peripheral edges sandwiched and fixed between the outer peripheral surface of the main body external body 51 and the inner surfaces of the cover members 83a and 83b in order to simplify the device configuration. A simple fixing structure is adopted. By doing so, for example, as shown in FIG. 1, a mounting plate 87, a spring receiving plate 97, and an air introduction pipe 86 for mounting a diaphragm 81 are placed in the edge cutting chamber 92. 1 and the spring receiving plate 97 and the spring 98 which are provided on the drainage chamber 102 side in FIG. 1 are not required, so that the number of parts can be reduced and the device configuration can be simplified. Yes. In addition, since there is no projecting portion in the lateral direction from the cover member 83 such as the cylindrical portion 88 shown in FIG.
[0055]
Further, in the fourth embodiment, the drainage passage 105 communicates with the downstream portion of the second check valve 68 only through the valve hole 95b, and the main valve chamber 93 communicates with the air introduction passage 21 only through the valve hole 95a. It is made up of a composition. Therefore, in a state where the edge cut valve 89 and the drain valve 99 are closed, the pressure from the edge cut back pressure chamber 91 is larger than the pressure receiving area of the diaphragm 81 that receives the pressure from the main valve chamber 93 side at the valve hole 95a. The pressure receiving area of the diaphragm 81 receiving the pressure is much larger (the pressure difference received from the valve hole 95a side and the pressure received from the negative pressure release chamber 90 side is large). When a stable valve closing state is maintained by the primary pressure on the 14 side and the inflow passage 14 side becomes negative (low pressure), a large force in the negative pressure direction is obtained, and the valve is quickly opened with good responsiveness. 21 can introduce air into the main valve chamber 93 to perform the edge cutting operation.
[0056]
Similarly, the pressure receiving area for receiving pressure from the drainage back pressure chamber 101 side is much larger than the pressure receiving area for pressure received from the valve hole 95b side on the diaphragm 82 side (pressure received from the valve hole 95b side and drainage back pressure chamber). Since the pressure difference from the pressure received from the 101 side becomes large), a stable valve closing state is maintained by the primary pressure on the inflow passage 14 side received from the drainage back pressure chamber 101 at normal times, and the inflow passage 14 side becomes negative (low pressure) ), A large force in the negative pressure direction can be obtained and the valve can be quickly opened with good responsiveness, and the sewage flowing backward from the outflow passage 15 can be drained from the drainage passage 105.
[0057]
Further, in the fourth embodiment, the air introduction passage 21 communicates directly with the negative pressure release chamber 90, and along the straight flow path from the main introduction passage 44 to the outflow passage 15 like the drainage passage 105. Extending downward (downstream of the straight flow path). By adopting this configuration, the air introduction passage 21 does not protrude in the lateral direction as shown in FIG. 1, so that the apparatus can be further reduced in size.
[0058]
In FIG. 4, the lower portion of the cylindrical shaft 72 of the first check valve 67 has a blade-like shape in which the plate portions 135 are formed at equal intervals around the circumference. Communication between the main valve chamber 93 and the valve hole 95a is achieved by utilizing the clearance. Further, upper portions of the cover members 83a and 83b are formed thick, and communication passages 134a and 134b communicating with the back pressure chambers 91 and 101 are formed in the wall portions, and the primary pressure communication passage 107 is formed by the communication passage 134a. And the negative pressure release chamber 90 communicate with each other, and the primary pressure communication passage 107 and the drainage back pressure chamber 101 communicate with each other by the communication passage 134b.
[0059]
Further, a ring-shaped support convex portion 132a is formed protruding from the bottom wall of the concave portion 79 so as to surround the outside of the valve seat 84 with a gap. The protruding height of the support convex portion 132a is substantially the same as the protruding height of the valve seat 84, and the diaphragm 81 is received and supported outside the valve seat 84 when the edge cut-off valve 89 is closed. Similarly, on the drain valve 99 side, a support projection 132b protrudes from the bottom wall of the recess 80, and the diaphragm 82 is received and supported outside the valve seat 94 when the drain valve 99 is closed.
[0060]
Further, in the example shown in FIG. 4, the valve seats (65, 61, etc.) of the check valves 67, 68, 110 are formed on the valve plate 76 side, but as shown in FIGS. You may form in the other party which a valve plate contact | abuts, and it is good also as a structure which removed the non-return valve 110, as FIG. 1, FIG. 3 shows.
[0061]
It goes without saying that the fourth embodiment also exhibits the same effects as those of the first embodiment, in addition to the effects unique to the above-described embodiment.
[0062]
FIG. 6 shows a fifth embodiment of the backflow prevention device 50 according to the present invention. The backflow prevention device 50 according to the fifth embodiment is configured not to have a drainage mechanism (drainage means) including the drainage valve 99, and other configurations are the backflow prevention according to the first embodiment. Since it is the same as the apparatus 50, the duplicate description of the structure is abbreviate | omitted. Similarly to the backflow prevention device 50 of the first embodiment, the backflow prevention device 50 of the fifth embodiment is used by being incorporated in a hot water supply system as shown in FIG. Also in this fifth embodiment, the configuration of the edge cut chamber 92 and the edge cut valve 89 can be the same as the configuration of the fourth embodiment shown in FIG.
[0063]
By the way, the installation location of the bathtub 1 in the home is various, and as shown in FIG. 5, when the bathtub 1 is installed at a position lower than the backflow prevention device 50, the primary pressure on the water supply source side is low. Since the main valve chamber 93 is opened to the atmosphere by the edge cut-off valve 89 as described above, backflow is prevented, so that the backflow prevention device 50 according to the second embodiment with the drain valve 99 removed is used for hot water supply. Even if it is incorporated in the system, no particular problem occurs.
[0064]
However, as shown in FIG. 7, when the bathtub 1 is installed at a position higher than the backflow prevention device 50 (for example, the bathtub 1 is installed on the second floor of the house, and the appliance (equipment case 39) is installed on the first floor. In the case where the backflow prevention device 50 is arranged between them, the head pressure on the bathtub 1 side is cut off by the edge cutout valve 89 of the backflow prevention device 50 (even if the main valve chamber 93 is opened to the atmosphere). If the check valves 67 and 68 do not operate normally due to the large value, the backflow cannot be prevented. In such a case, if the drainage valve 99 is provided as in the backflow prevention device 50 of the first to fourth embodiments, the backflowed water is drained, so that the backflow sewage is directed to the main valve chamber 93 side. However, when the backflow prevention device 50 of the fifth embodiment shown in FIG. 6 is used, since the drain valve 99 is not provided, the check valves 67 and 68 do not operate normally. Therefore, it becomes impossible to prevent the backflow.
[0065]
FIG. 7 shows an embodiment of a system configuration capable of preventing backflow even when the backflow prevention device 50 of the fifth embodiment is incorporated in a hot water supply system in which the bathtub 1 is installed at a high position. Indicates. In the hot water supply system of FIG. 7, the backflow prevention device 50 having the configuration shown in FIG. 6 is provided, and the bathtub 1 is installed at a position higher than the backflow prevention device 50. The backflow prevention device 50 is incorporated into the hot water supply system by connecting the inflow passage forming cylinder portion 45 to the branch pipe 7 and the outflow passage forming cylinder portion 78 to the drop pipe 8.
[0066]
A characteristic of the hot water supply system shown in FIG. 7 is that a drainage device 112 is externally disposed in a drop pipe 8 of a passage for supplying hot water from a water heater 2 as a hot water supply device to the bathtub 1. FIG. 8 schematically shows an example of the configuration of the drainage device 112. The internal space of the valve housing 114 is divided into a valve chamber 115 and a back pressure chamber 116 by a diaphragm 117, and the diaphragm 117 is placed in the valve chamber 115. A valve body 118 having a proximal end portion fixed at the center is disposed.
[0067]
A valve plate 119 is provided on the distal end side of the valve body 118, and a valve seat 125 is formed on the wall portion of the valve housing 114 facing the valve plate 119. A reverse flow inflow passage 121 communicating with the valve hole of the valve seat 125 is formed by a cylindrical hole of the cylindrical part 122, and the cylindrical part 122 is connected to the drop pipe 8 through the communication pipe 113. A valve spring 120 that urges the valve body 118 in the valve opening direction is disposed between the base plate 126 of the valve body 118 and the wall surface of the valve housing 114 facing the plate portion 126. In addition, a cylindrical portion 123 projects downward from the valve chamber 115, and a cylindrical hole of the cylindrical portion 123 forms a drainage passage 124.
[0068]
A primary pressure supply pipe 9 is connected to a cylindrical portion 127 projecting from the wall surface of the valve housing 114 on the back pressure chamber 116 side, so that the primary pressure (water pressure) of the water supply source is applied to the back pressure chamber 116, and the primary pressure supply pipe 9 is applied. During normal times when there is no pressure drop, the diaphragm 117 is deflected to the valve seat 125 side against the biasing force of the valve spring 120 by the primary pressure, and the valve plate 119 is pressed against the valve seat 125 to maintain the valve closed state. To do. On the other hand, the pressure in the back pressure chamber 116 decreases when the primary pressure decreases due to water shut-off or the like, thereby closing the force in the valve opening direction due to the urging force of the valve spring 120 and the secondary pressure applied to the reverse flow inflow passage 121 side. As a result of overcoming the force in the valve direction and the diaphragm 117 being deformed in the valve opening direction, the valve plate 119 is opened away from the valve seat 125, and the sewage that drops from the bathtub 1 side and flows backward to the pipe 8 side is discharged from the communication pipe 113. It enters the valve chamber 115 and is drained through the drainage passage 124. Therefore, the sewage does not flow back to the backflow prevention device 50 that is open to the atmosphere, and the sewage is reliably prevented from entering the hot water supply pipe 6 side through the branch pipe 7.
[0069]
Moreover, since the draining operation is performed separately on the drainage device 112 side and the main valve chamber 93 is opened to the atmosphere (edge cutting) on the backflow prevention device 50 side, the draining operation and the edge cutting operation are performed separately and independently. There is no occurrence of the above-mentioned conventional problem that occurs when the air introduction passage and drainage passage are combined for edge cutting, and the edge cutting and drainage operations can be performed quickly and reliably.
[0070]
In addition, this invention can take various embodiment, without being limited to each said embodiment. For example, the drainage device 112 is configured as a diaphragm responsive valve. However, the drainage device 112 may have another valve configuration as long as it has a valve mechanism that detects a reverse flow or a drop in the primary pressure. . However, the configuration of the diaphragm responsive valve as in this embodiment is advantageous because the drainage operation of the backflow sewage can be reliably performed without being affected by it even in the case of a power failure.
[0071]
In the fourth embodiment, the edge cutting chamber 92 and the drainage chamber 102 have the same structure, and the edge cutting valve 89 and the drainage valve 99 have the same structure. The configuration of the valves is not necessarily the same. Also in the first to third embodiments, the configuration of the chambers on the edge cutting side and the drainage side and the configuration of the valves may be the same or not necessarily the same.
[0072]
In the above embodiment, the backflow prevention device 50 is incorporated and used in the hot water supply system. However, the backflow prevention device of the present invention is equipped as a device for preventing backflow in the fluid flow path other than the hot water supply system. Is possible.
[0073]
【The invention's effect】
According to the backflow prevention device of the present invention having both the edge cut-off valve and the drainage valve and the hot water supply system having the backflow prevention device, the water supply side regardless of whether the main control valve is open or closed. The primary pressure is used to maintain the edge valve and the drain valve in the closed state, and when the primary pressure is reduced (negative pressure), the pressure drop is applied to the edge valve and the drain valve. The drainage valve and the drainage valve are both opened, and the drainage of the fluid (water) that has flowed back to the edge is performed separately. Therefore, the primary pressure can be used as it is as a valve drive source for the edge-cutting valve and drainage valve, and the device configuration can be simplified, downsized, and cost-reduced, and the edge-cutting and drainage can be performed without being affected by electrical system failures such as power outages. Thus, the operation of the apparatus can be reliably performed, and the reliability of the operation of the apparatus can be improved.
[0074]
In particular, in the invention in which the air introduction passage communicates directly with the negative pressure release chamber, and the negative pressure release chamber communicates with the main valve chamber only through the valve hole of the edge cut valve, the diaphragm of the edge cut valve Since the pressure receiving area of the pressure received from the edge cut back pressure chamber side can be much larger than the pressure receiving area of the pressure received from the valve hole side, the pressure received by the diaphragm from the edge cut back pressure chamber side and the pressure received from the valve hole side The differential pressure can be increased. As a result, a large valve closing force is obtained by the primary pressure from the edge cutting back pressure chamber at normal times, and the closed state of the edge cutting valve is reliably maintained stably. When the primary pressure on the water supply side decreases (negative pressure), the edge cutting occurs. A large negative pressure force is obtained from the back pressure chamber side, and the valve opening operation (edge cutting operation) of the edge valve is performed quickly (with good responsiveness), and the backflow of sewage from the outflow passage side can be reliably prevented. The reliability of preventing backflow can be sufficiently increased.
[0075]
In addition, the backflow prevention device of the present invention having only the edge cut-off valve and the hot water supply system having the backflow prevention device of the edge cut-off valve and the drain valve are in either the valve drive operation state of the main control valve being opened or closed. Regardless, the primary pressure on the water supply side is used to maintain the edge cut-off valve in a closed state, and when the primary pressure is reduced (negative pressure), the pressure drop is applied to the edge cut-off valve to activate the edge cut-off valve. Since it is configured to open the valve and perform edge cutting, the primary pressure can be used as it is as the valve drive source for the edge cutting valve, simplifying the device configuration, reducing the cost, and impacting electrical system failures such as power outages. Therefore, it is possible to reliably perform the edge cutting and drainage operations without increasing the reliability of the apparatus.
[0076]
Furthermore, since the backflow prevention device of the present invention can be incorporated into a hot water supply system by simply connecting pipe lines to the inflow passage and the outflow path, that is, by connecting only two pipe lines, the piping configuration is clean. And piping connection work becomes easy.
[0077]
Furthermore, according to the hot water supply system provided with the backflow prevention device of the present invention having both the edge cut-off valve and the drain valve, and the hot water supply system of the present invention separately provided with the backflow prevention device having only the edge cut-off valve, the primary pressure is increased. At the time of an abnormality that decreases, the edge cutting operation by the edge cutting valve and the draining operation of the backflow water by the drain valve (drainage device) can be performed as separate operations. Therefore, the external air introduction passage for edge cutting and the backflow water drainage passage are respectively dedicated passages, and the problem of the conventional example caused by the combined use of one passage is solved. Edge cutting and backflow drainage can be performed quickly and reliably, and a highly reliable apparatus and system can be provided.
[0078]
Furthermore, since the backflow prevention device of the present invention normally receives the primary pressure and the edge cut-off valve and the drainage valve are closed, foreign matters such as dust from the outside through the air introduction passage and the drainage passage The effect that it can prevent entering into is obtained.
[Brief description of the drawings]
FIG. 1 is a configuration explanatory view of a backflow prevention device according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating the configuration of a backflow prevention device according to a second embodiment of the present invention.
FIG. 3 is a diagram illustrating the configuration of a backflow prevention device according to a third embodiment of the present invention.
FIG. 4 is a diagram illustrating the configuration of a backflow prevention device according to a fourth embodiment of the present invention.
FIG. 5 is a diagram illustrating the configuration of a hot water supply system incorporating the backflow prevention device according to the first embodiment.
FIG. 6 is a diagram illustrating the configuration of a backflow prevention device according to a fifth embodiment of the present invention.
FIG. 7 is a configuration explanatory view of a hot water supply system incorporating a backflow prevention device according to a fifth embodiment.
FIG. 8 is a schematic configuration diagram of a drainage device incorporated in the hot water supply system of FIG.
9 is an explanatory view of a conventional backflow prevention device disclosed in Patent Document 1. FIG.
10 is an explanatory diagram of a conventional hot water supply system incorporating the backflow prevention device of FIG. 9;
FIG. 11 is an explanatory diagram of a conventional backflow prevention device disclosed in Patent Document 2.
[Explanation of symbols]
2 Water heater (hot water supply device)
14 Inflow passage
15 Outflow passage
21 Air introduction passage
48 Pilot solenoid valve (Main control valve)
50 Backflow prevention device
67 First check valve (check valve)
68 Second check valve (backflow prevention valve)
89 Edge cut valve
90 Negative pressure release chamber
91 Edge-cutting back pressure chamber
92 Edge cutting room
93 Main valve chamber
99 Drain valve
100 Wastewater treatment room
101 Drain back pressure chamber
102 Drainage chamber
105 Drainage passage
107 Primary pressure communication passage
112 Drainage device

Claims

装置内に、流入通路と、この流入通路からの流入流体をメーン弁室に導入するメーン導入通路と、前記メーン弁室の出口側に連通して前記流入流体を流出する流出通路とを有し、前記メーン導入通路の入口部には開弁によって流入通路からの流入流体を導入し閉弁によって流入流体の導入を遮断するメーン制御弁が設けられ、前記メーン弁室の入口側と出口側にはそれぞれ流入流体の流入順方向圧力によって開弁し逆流を閉弁によって阻止する逆流防止弁が設けられており、また、装置内には縁切り室が設けられ、この縁切り室はダイアフラムを介して縁切り背圧室と前記メーン弁室に連通する負圧開放室とに区分され、この負圧開放室には外部の空気を導入する空気導入通路が縁切り弁を介して連通され、前記縁切り背圧室は装置内に形成された一次圧連通通路を介して前記流入通路に連通されており、前記縁切り弁は常時は前記縁切り背圧室に印加される流入通路側の一次圧を受けて前記ダイアフラムを負圧開放室側に撓み変形させることで縁切り弁を閉じて前記空気導入通路とメーン弁室との連通を遮断し、前記流入通路が低圧化された時に前記ダイアフラムがその低圧化に応じた圧力を前記縁切り背圧室側から受けて該縁切り背圧室側に撓み復帰変形することで前記縁切り弁を開き前記空気導入通路とメーン弁室とを連通させて前記メーン弁室を大気に開放するダイアフラム応動弁として構成した逆流防止装置。The apparatus has an inflow passage, a main introduction passage for introducing the inflow fluid from the inflow passage into the main valve chamber, and an outflow passage for communicating with the outlet side of the main valve chamber and outflowing the inflow fluid. A main control valve is provided at the inlet portion of the main introduction passage to introduce the inflow fluid from the inflow passage by opening the valve and shut off the introduction of the inflow fluid by closing the valve. Each is provided with a backflow prevention valve that opens by the inflow forward pressure of the inflowing fluid and blocks backflow by closing the valve, and an edge cutting chamber is provided in the apparatus, and this edge cutting chamber is provided with an edge cutting through a diaphragm. The back pressure chamber is divided into a negative pressure release chamber communicating with the main valve chamber, and an air introduction passage for introducing external air is communicated to the negative pressure release chamber via an edge cut valve. Formed in the device The edge cut valve communicates with the inflow passage via the primary pressure communication passage, and the edge cut-off valve normally receives the primary pressure on the inflow passage side applied to the edge cut back pressure chamber, thereby removing the diaphragm from the negative pressure release chamber side. When the inflow passage is reduced in pressure, the diaphragm applies a pressure corresponding to the reduced pressure to the edge cut back pressure by closing the edge cut valve by bending and deforming to cut off the communication between the air introduction passage and the main valve chamber. It is configured as a diaphragm responsive valve that receives from the chamber side and flexes and returns to the edge-cutting back pressure chamber side to open the edge-cutting valve and connect the air introduction passage and the main valve chamber to open the main valve chamber to the atmosphere. Backflow prevention device.

装置内に、流入通路と、この流入通路からの流入流体をメーン弁室に導入するメーン導入通路と、前記メーン弁室の出口側に連通して前記流入流体を流出する流出通路とを有し、前記メーン導入通路の入口部には開弁によって流入通路からの流入流体を導入し閉弁によって流入流体の導入を遮断するメーン制御弁が設けられ、前記メーン弁室の入口側と出口側にはそれぞれ流入流体の流入順方向圧力によって開弁し逆流を閉弁によって阻止する逆流防止弁が設けられており、また、装置内には縁切り室と排水室とが設けられ、前記縁切り室はダイアフラムを介して縁切り背圧室と前記メーン弁室に連通する負圧開放室とに区分され、この負圧開放室には外部の空気を導入する空気導入通路が縁切り弁を介して連通され、前記縁切り背圧室は装置内に形成された一次圧連通通路を介して前記流入通路に連通されており、前記縁切り弁は常時は前記縁切り背圧室に印加される流入通路側の一次圧を受けて前記ダイアフラムを負圧開放室側に撓み変形させることで縁切り弁を閉じて前記空気導入通路とメーン弁室との連通を遮断し、前記流入通路が低圧化された時に前記ダイアフラムがその低圧化に応じた圧力を前記縁切り背圧室側から受けて該縁切り背圧室側に撓み復帰変形することで前記縁切り弁を開き前記空気導入通路とメーン弁室とを連通させて前記メーン弁室を大気に開放するダイアフラム応動弁として構成し、前記排水室はダイアフラムを介して排水背圧室と前記流出通路に連通する排水処理室とに区分され、この排水処理室は排水弁を介して排水通路に連通され、前記排水背圧室は装置内に形成された一次圧連通通路を介して前記流入通路に連通されており、前記排水弁は常時は前記排水背圧室に印加される流入通路側の一次圧を受けて前記ダイアフラムを排水処理室側に撓み変形させることで排水弁を閉じて前記排水通路と前記流出通路との連通を遮断し、前記流入通路が低圧化された時に前記ダイアフラムがその低圧化に応じた圧力を前記排水背圧室側から受けて該排水背圧室側に撓み復帰変形することで前記排水弁を開き前記流出通路と排水通路とを連通させるダイアフラム応動弁として構成した逆流防止装置。The apparatus has an inflow passage, a main introduction passage for introducing the inflow fluid from the inflow passage into the main valve chamber, and an outflow passage for communicating with the outlet side of the main valve chamber and outflowing the inflow fluid. A main control valve is provided at the inlet portion of the main introduction passage to introduce the inflow fluid from the inflow passage by opening the valve and shut off the introduction of the inflow fluid by closing the valve. Each is provided with a backflow prevention valve that opens by the inflow forward pressure of the inflowing fluid and blocks backflow by closing the valve, and an edge cutting chamber and a drainage chamber are provided in the apparatus, and the edge cutting chamber is a diaphragm. Through the edge cutting back pressure chamber and a negative pressure release chamber communicating with the main valve chamber, and an air introduction passage for introducing external air is communicated with the negative pressure release chamber through the edge cutting valve. The edge cutting back pressure chamber is The inflow passage is communicated with the inflow passage through a primary pressure communication passage formed in the inside, and the edge cut-off valve normally receives the primary pressure on the inflow passage side applied to the edge cut back pressure chamber and negatively pressures the diaphragm. The edge cut-off valve is closed by bending and deforming to the open chamber side to cut off the communication between the air introduction passage and the main valve chamber, and when the inflow passage is reduced in pressure, the diaphragm applies a pressure corresponding to the reduced pressure. Diaphragm responsive to receive from the edge cutting back pressure chamber side and to bend and return to the edge cutting back pressure chamber side to open the edge cutting valve and to connect the air introduction passage and the main valve chamber to the atmosphere. The drainage chamber is divided into a drainage back pressure chamber and a drainage treatment chamber communicating with the outflow passage via a diaphragm, and the drainage treatment chamber is communicated with the drainage passage via a drainage valve. The pressure chamber communicates with the inflow passage through a primary pressure communication passage formed in the apparatus, and the drain valve receives the primary pressure on the inflow passage side which is normally applied to the drain back pressure chamber and receives the primary pressure. The diaphragm is bent and deformed to the side of the waste water treatment chamber to close the drain valve to cut off the communication between the drain passage and the outflow passage, and when the inflow passage is decompressed, the diaphragm responds to the pressure reduction. The backflow prevention device is configured as a diaphragm responsive valve that opens the drainage valve and allows the outflow passage and the drainage passage to communicate with each other by receiving from the drainage back pressure chamber side and bending to the drainage back pressure chamber side.

メーン導入通路と、メーン弁室と、流出通路とを順に通る流路は直線状の流路と成し、前記メーン弁室の外周側領域に縁切り室と排水室とが分離して形成され、流入通路の出口側はメーン制御弁を介してメーン導入通路に導かれる通路と、前記縁切り背圧室及び排水背圧室とに導かれる一次圧連通通路とに連通され、前記メーン制御弁の開閉に依存せずに流入通路側の一次圧によって常時縁切り弁と排水弁を閉じ、前記一次圧が低圧化した異常時にのみ前記縁切り背圧室と排水背圧室の圧力低下に依存して縁切り弁と排水弁を開放する構成とした請求項２記載の逆流防止装置。A flow path that passes through the main introduction passage, the main valve chamber, and the outflow passage in order is a straight flow passage, and an edge cutting chamber and a drainage chamber are separately formed in the outer peripheral side region of the main valve chamber, The outlet side of the inflow passage is communicated with a passage led to a main introduction passage through a main control valve and a primary pressure communication passage led to the edge-cut back pressure chamber and the drain back pressure chamber, and opens and closes the main control valve. The edge cut valve and drain valve are always closed by the primary pressure on the inflow passage without depending on the pressure, and the edge cut valve depends on the pressure drop in the edge cut back pressure chamber and the drain back pressure chamber only when the primary pressure is lowered. The backflow prevention device according to claim 2, wherein the drain valve is opened.

縁切り室と排水室は同一形状に形成され、縁切り室の縁切り背圧室に連通する空気導入通路と排水室の排水処理室に連通する排水通路は共にメーン導入通路から流出通路に至る直線状の流路に沿い同流路の下流側に向けて延設されていることを特徴とする請求項３記載の逆流防止装置。The edge cutting chamber and the drainage chamber are formed in the same shape, and the air introduction passage communicating with the edge cutting back pressure chamber of the edge cutting chamber and the drainage passage communicating with the wastewater treatment chamber of the drainage chamber are both linear from the main introduction passage to the outflow passage. 4. The backflow prevention device according to claim 3, wherein the backflow prevention device extends along a flow path toward a downstream side of the flow path.

空気導入通路が縁切り弁を介して負圧開放室に連通される構成に代えて、空気導入通路は直接的に負圧開放室に連通され、負圧開放室は縁切り弁の弁孔のみを介してメーン弁室に連通されていることを特徴とする請求項１又は請求項２又は請求項３又は請求項４記載の逆流防止装置。Instead of a configuration in which the air introduction passage is communicated with the negative pressure release chamber via the edge cut valve, the air introduction passage is directly communicated with the negative pressure release chamber, and the negative pressure release chamber is connected only through the valve hole of the edge cut valve. The backflow prevention device according to claim 1, claim 2, claim 3, or claim 4, wherein the backflow prevention device is communicated with the main valve chamber.

給湯装置から浴槽に湯を供給する通路の途中に請求項２又は請求項３又は請求項４又は請求項５記載の逆流防止装置が介設されていることを特徴とする給湯システム。A hot water supply system, wherein the backflow prevention device according to claim 2, claim 3, claim 4, or claim 5 is interposed in the middle of a passage for supplying hot water from a hot water supply device.

給湯装置から浴槽に湯を供給する通路の途中に請求項１記載の逆流防止装置が介設され、この逆流防止装置よりも下流側の通路に浴槽側から逆流した流体を排水する排水装置が外付け設置されている給湯システム。The backflow prevention device according to claim 1 is interposed in the middle of a passage for supplying hot water from the hot water supply device, and a drainage device for draining the fluid backflowed from the bathtub side to the downstream side of the backflow prevention device is provided. A hot water supply system installed.