JP4710071B2

JP4710071B2 - Check valve and double check valve, depressurization type check valve applying the check valve

Info

Publication number: JP4710071B2
Application number: JP2001326963A
Authority: JP
Inventors: 有里子永島
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-09-19
Filing date: 2001-09-19
Publication date: 2011-06-29
Anticipated expiration: 2021-09-19
Also published as: JP2003090448A

Description

【０００１】
【発明の属する技術分野】
本発明は流体を供給する配管、装置等に取り付けて流体の逆流を防止する逆止弁に関する。特に水道水の配管に直結して使用する装置の逆流を防止する逆止弁、複式逆止弁と直結給水装置に用いる減圧式逆流防止器に関するものである。
【０００２】
【従来の技術】
流体、特に給水、給湯システムにおける逆止弁は、給水、給湯システム全体の汚染の原因となる逆流を防止する弁であり、最重要部品の一つである。従来の逆止弁は、図５のように、ハウジングＡの入口７と出口８を結ぶ流路に弁座１５を形設して、出口側より弁座１５に密着する面を弾性体から成る弁１８とした弁体５を離接自在に装着し、常時バネ２１により弁座１５に密着付勢させて、入口７から流入した流体の流体圧力と出口側の流体圧力との差圧により弁１８を押す力がバネ力に勝った場合に開弁して出口方向に流体が流出し、差圧による弁１８を押す力がバネ力未満（入口側流体圧力が出口側流体圧力より低い）の場合は閉弁し流体の流れを止め逆流を防ぐ構造である。
【０００３】
さらに逆流を確実に防ぐバルブとして複式逆止弁がある。従来の複式逆止弁は図６に示す如くハウジングＡの入口７と出口８を結ぶ流路に、前述の逆止弁を第一逆止弁２７、第二逆止弁２８として二組み組み込んだものである。
【０００４】
又、図１２に従来の減圧式逆流防止器を示す。従来の減圧式逆流防止器は、ハウジングＡの入口７と出口８を結ぶ流路に、前述の逆止弁を第一逆止弁２７、第二逆止弁２８として二組み装着して、第一逆止弁２７の上流の入口７と第一逆止弁２７の間の一次室２５と、第一逆止弁２７と第二逆止弁２８の間の中間室１１と、第二逆止弁２８と出口８の間の二次室１２と、に流路を分離し、一次室２５と中間室１１との差圧を感知して可動するダイアフラムＢ２９を水密に組み付け、そのダイアフラムＢ２９に中間室１１と連通孔Ｂ３９で連通する第二圧力室３３と外部排出口４１を連通する連通孔３０の開口の第二圧力室側周囲に形設した弁座Ｃ３１に対向する弁Ｃ３２を一体的に形設して、一次室２５の圧力が中間室１１の圧力より高い場合に、弁Ｃ３２が弁座Ｃ３１に密着して閉弁し、一次室２５の圧力より中間室１１の圧力が高くなった場合に、開弁して中間室１１を外部排出口４１に開放して、万一、第一逆止弁２７、第二逆止弁２８に漏れが生じた場合でも逆流を防ぐ装置である。
【０００５】
【発明が解決しようとする課題】
逆止弁は流量抵抗が小さくて逆流防止能力（シール力）の高い事が要求される。従来の逆止弁

ると流量抵抗は小さくなるがシール力が小さくなり、Ｆを大きくするとシール力が大きくなるが、流量抵抗も大きくなって相反する。従って、流量抵抗の許される範囲でシール力を決定している。
【０００６】
複式逆止弁は前述の逆止弁を二組み使用するので同様の課題を持っており、又、同一の構造の逆止弁の組み合わせは同じ故障を起こす可能性が高く、異なる構造の逆止弁の組み合わせが望まれている。又、逆止弁を二組み使用する減圧式逆流防止器も同様である。流量抵抗が小さくて逆流防止能力の高い逆止弁及び異なる構造の逆止弁を組み合わせた複式逆止弁が切望されている。
【０００７】
【課題を解決するための手段】
従来の逆止弁では図５の例のようにハウジングの入り口と出口を結ぶ流路にハウジングと一体となった弁座を形成して、その弁座に対して、弁が入口圧力と出口圧力の差圧を感知して可動し、弁座に密着離脱し流れを開閉するので、流体を開閉する弁が差圧を感知する感圧盤の働きを兼務する為に、前述の通りに流量抵抗を小さくすることと弁シール力を高めることが相反する結果となる。
【０００８】
本発明ではハウジングの入り口と出口を結ぶ流路に水室を形設し、該水室に水室を入口側より中間室と二次室とに水密に区画し軸方向に可動し、軸心部位に中間室と二次室を連通する透孔を設けた感圧盤を装設し、その感圧盤の透孔の中間室側周囲に弁座Ａを形設して、中間室側から弁座Ａに密着離脱する弁体を対向させ、弁体の弁座Ａに密着する面に弾性体から成る弁Ａを形成して、常時弁Ａが弁座Ａに密着して閉弁するように弁体を付勢手段により付勢し、弁体の入口側への移動距離を制限する入口ストッパー及び弁体の出口側への移動距離を制限する出口ストッパーを設け、感圧盤が出口側に移動して弁体が出口ストッパーに当たると、弁座Ａが弁Ａを離れ開弁し、感圧盤が入口側に移動すると弁体が入口ストッパーに当たり、感圧盤に加わる流体の差圧力が弁Ａに弁座Ａを押しつける力となる逆止弁となっている。
【０００９】
入口側流体圧力が出口側流体圧力より高い場合（正常状態）、流入した流体は感圧盤と感圧盤の弁座Ａに付勢手段により付勢された弁体を出口側に押し動かす。弁体が弁体の出口側への動きを制限する出口ストッパーに当たると、弁体が出口側に移動できなくなり感圧盤のみが移動し、感圧盤の弁座が弁Ａを離れ開弁する。入口側流体圧力が出口側流体圧力より低い場合（逆圧状態）、出口側流体圧力により感圧盤と感圧盤の弁座Ａに付勢手段により付勢された弁体は、閉弁した状態で入口側に押し動かされる。弁体が弁体の入口側への動きを制限する入口ストッパーに当たると、弁体を付勢する付勢力に加え感圧盤に加わる差圧力が弁Ａに弁座Ａを押しつけシール力を増加する。
【００１０】
以上の如く弁座をハウジングと分離してハウジングに対し可動する感圧盤に形設する構造とすることで、差圧を感知する感圧盤と流体を開閉する弁が別体となり、流量抵抗を小さくすることとシール力を高めることが両立できるようになる。
【００１１】
請求項２記載の発明では、ハウジングの入口と出口を結ぶ流路に水室を形設し、該水室に水室を入口側より中間室と二次室とに水密的に区画し軸方向に可動し、軸心部位に中間室と二次室を連通する透孔を設けた感圧盤を装設し、その感圧盤の透孔の中間室側周囲に弁座Ａを形設し、入口と中間室を結ぶ流路の中間室の入口周囲にハウジングと一体又は一体的に弁座Ｂを形設して、弁座Ａと弁座Ｂの間の中間室に弁座Ａに密着する面に弾性体から成る弁Ａと弁座Ｂに密着する面に弾性体から成る弁Ｂを形成した弁体を組み付け、弁座Ａに弁Ａ、弁座Ｂに弁Ｂをそれぞれ対向させ、常時弁Ａが弁座Ａに密着して閉弁するように弁体を付勢手段により付勢し、弁体の出口側への移動距離を制限する出口ストッパーを設け、感圧盤が出口側に移動して弁体が出口ストッパーに当たると、弁座Ａが弁Ａを離れ開弁し、感圧盤が入口側に移動して弁体が入口側へ移動すると弁Ｂが弁座Ｂに当たり流路を閉弁する複式逆止弁となっている。
【００１２】
入口側流体圧力が出口側流体圧力より高い場合（正常状態）、流入した流体は感圧盤と感圧盤の弁座Ａに付勢手段により付勢された弁体を出口側に押し動かし、弁座Ｂから弁Ｂを離し開弁する。更に出口側に動き弁体が弁体の出口側への動きを制限する出口ストッパーに当たると、弁体が出口側に移動できなくなり感圧盤のみが移動し、感圧盤の弁座Ａが弁Ａを離れ開弁する。
【００１３】
入口側流体圧力が出口側流体圧力より低い場合（逆圧状態）、出口側流体圧力により感圧盤と感圧盤の弁座Ａに付勢手段により付勢された弁体は閉弁状態で入口側に押し動かされ、弁体の弁Ｂが弁座Ｂに当たり閉弁し、弁体を付勢する付勢力に加え感圧盤に加わる差圧力が弁Ａに弁座Ａを押しつけると共に弁Ｂを弁座Ｂに押しつけシール力を増加する。
【００１４】
従って、複式逆止弁の一方の弁座Ａと弁Ａによる開閉機構は弁に感圧盤に形設した弁座が密着離脱して開閉し、他方弁座Ｂと弁Ｂによる開閉機構はハウジングに形設した弁座に弁が密着離脱して開閉する逆止弁として作動するので違った構造の逆止弁を組み合わせた複式逆止弁となる。
【００１５】
請求項３記載の発明の減圧式逆流防止器は、ハウジングの入口と出口を結ぶ流路に従来逆止弁を第一逆止弁、第二逆止弁として二組み装着して、第一逆止弁の上流の入口と第一逆止弁の間の一次室と、第一逆止弁と第二逆止弁の間の中間室と、第二逆止弁と出口の間の二次室と、に流路を分離する変わりに、前述複式逆止弁を装着し該複式逆止弁の弁座Ｂと弁Ｂによる開閉機構を第一逆止弁、弁座Ａと弁Ａによる開閉機構を第二逆止弁として一次室、中間室、二次室とに分離するのだから、前述の複式逆止弁と同様の効果を得ることとなり、安全性の高い減圧式逆流防止器となる。
【００１６】
請求項４記載の発明では、弁体を、弁座Ａに密着する面に弾性体から成る弁Ａを形成した弁体Ａと、弁座Ｂに密着する面に弾性体から成る弁Ｂを形成した弁体Ｂに分離して、弁体Ａに対して弁体Ｂが設定した距離軸方向に可動に組み付け、弁体Ａと弁体Ｂの間に、弁体Ａと弁体Ｂを引き離すように付勢手段を付勢して、弁体Ａの入口側への移動距離を制限する弁体Ａストッパーを弁Ｂが弁座Ｂに当接してから、弁体Ａが入口側へ０．１ｍｍ〜３ｍｍ動いてから止まる位置に装設したのであるから、
【００１７】
弁座Ｂから弁体Ｂを押し離して開弁するのは、入口から流入した流体の一次室圧力と中間室圧力の差と弁Ｂの面積の積が弁体Ａと弁体Ｂの間に付勢した付勢力に勝ったときであり、逆圧状態になると、弁座Ｂに弁Ｂが当接するまで弁体Ａと弁体Ｂは一体的に動き、弁座Ｂに弁Ｂが当接すると弁体Ａは弁体Ａと弁体Ｂの間に付勢した付勢力に対抗して０．１ｍｍ〜３ｍｍ動いて弁座Ｂに弁Ｂを圧接してから弁体Ａストッパーに当たり止まるので、弁Ｂを弁座Ｂに圧接する力は弁体Ａと弁体Ｂの間に付勢した付勢力と一次室圧力と中間室圧力の差圧となり、弁座Ｂと弁Ｂによる開閉機構は感圧盤及び感圧盤に付勢手段により付勢された弁体Ａに関係しない逆止弁となる。その他の作動は前述の複式逆止弁の弁体と変わらない。
【００１８】
【実施例】
次に実施例を図面に従い詳述する。なお、図面符号は、従前手段のものと同効の構成部材については同一の符号を用いるものとする。
【００１９】
図１は、本発明を実施する感圧盤をダイアフラム式とした逆止弁の縦断面図で、同図において、Ａはハウジング、１はハウジングＡの入口７を具備する入口ハウジング、２はハウジングＡの出口８を具備する出口ハウジング、３はダイアフラム４に弁体５、弁座金具６等を組み付けた感圧盤となるダイアフラムＡＳＳＹであり、入口ハウジング１と出口ハウジング２によりダイアフラムＡＳＳＹ３を水密に狭持しネジ（図示せず）により結合することで組み付けられる。
【００２０】
入口ハウジング１は入口７と、入口７の他の面にダイアフラム４を水密に狭持するための鍔９と内腔に中間室１１を設け、入口７と中間室１１とを結ぶ流路の中間室近傍に、鍔９と中心軸を同じにして、弁体５の入口側への移動距離を制限する入口ストッパー１３を形設してある。
【００２１】
出口ハウジング２は出口８と、出口８の他端面にダイアフラム４を水密に狭持するための鍔１０と内腔に二次室１２を設け、出口８と二次室１２とを結ぶ流路の二次室近傍に、鍔９と中心軸を同じにして、弁体５の出口側への移動距離を制限する出口ストッパー１４を形設してある。
【００２２】
ダイアフラムＡＳＳＹ３は外周縁部に狭持部を設けたダイアフラム４の中心部位に穴を設け、その穴に中心部に中間室１１と二次室１２を連通する透孔を設けた弁座金具６をカシメ等により水密に取り付ける。該弁座金具６の中間室側の透孔周囲に弁座Ａ１５を形成し、透孔の中心部位にはボス２２を形成し、ボス２２の軸心部に弁体５の弁軸１９を嵌挿する貫通孔１６を形設して、弁金具１７に弾性体から成る弁Ａ１８を弁軸１９により固定した弁体５を、弁座Ａ側からボス２２の貫通孔１６に弁体５の弁軸１９を嵌挿し弁Ａ１８を弁座Ａ１５に対向させて組み付け、ボス２２の端面と弁軸１９の先端部の間にプッシュナット２０によりバネＡ２１を付勢して、弁Ａ１８を弁座Ａ１５に常時密着状態としてある。
【００２３】
しかして、入口ハウジング１にダイアフラムＡＳＳＹ３を弁体５が入口ハウジング側としてセットし、出口ハウジング２を載せてネジ（図示せず）で結合することで組み立てられる。
【００２４】
そして入口７から流入した流体は流路を経て中間室１１に入り、中間室１１と二次室１２の差圧により、ダイアフラム４とバネＡ２１で弁座Ａ１５に密着させた弁体５を出口側に押し動かす。弁体５の弁軸１９先端が出口ストッパー１４に突き当たると、弁体５が出口側に動けなくなるので、ダイアフラム４に取り付けられている弁座Ａ１５はバネＡ２１を撓ませて弁Ａ１８を離れ出口側に動き図２の如くに開弁して流体を出口８に流出する。
【００２５】
出口側の圧力が入口側圧力より高い逆圧が発生すると、中間室１１と二次室１２の差圧により、ダイアフラム４が入口側に動き、バネＡ２１により弁座Ａ１５が弁Ａ１８に当接して閉弁し、さらに弁座Ａ１５と弁Ａ１８が閉弁した状態で入口側に動き、弁体５の入口側端部が入口ストッパー１３に突き当たり図１に示す如くに弁体５が停止すると、弁座Ａ１５が弁Ａ１８を圧接する力はバネＡ２１の付勢力に、ダイアフラム４に係る差圧の力が加わりシール力を増加する。
【００２６】
図３は本発明を実施する複式逆止弁の縦断面図である。入口ハウジング１は入口７と、入口７の他端面にダイアフラム４を水密に狭持するための鍔９と内腔に中間室１１を設け、入口７と中間室１１とを結ぶ流路の中間室近傍に、鍔９と中心軸を同じにして弁座Ｂが形成してある。出口ハウジング２は前述の逆止弁の出口ハウジング２と変わりない。
【００２７】
ダイアフラムＡＳＳＹ３は弁体５の弁金具１７の両面に弾性体から成る弁を組み込む凹部を設け、一面に弁座Ａ１５に対向する弁Ａ１８を他面に前記弁座Ｂ２３に対向する弁Ｂ２４を組み付けて、弁Ａ側から弁軸１９で固定して弁体５とする以外は前述の逆止弁のダイアフラムＡＳＳＹ３と変わりない。
【００２８】
入口ハウジング１にダイアフラムＡＳＳＹ３を弁体５が入口ハウジング側としてセットし、出口ハウジング２を載せてネジ（図示せず）で結合することで組み立てることは前述の逆止弁の実施例と変わりない。
【００２９】
そして入口７から流入した流体は流路を経て入口７と弁座Ｂ２３の間の一次室２５に入り、一次室２５と中間室１１の差圧により、ダイアフラム４とバネＡ２１で弁座Ａ１５に付勢された弁体５を押し動かして、弁Ｂ２４を弁座Ｂ２３から押し離し開弁して中間室１１に入り、中間室１１と二次室１２の差圧により、ダイアフラム４とバネＡ２１で弁座Ａ１５に密着させた弁体５を出口側に押し動かす。弁体５の弁軸１９先端が出口ストッパー１４に突き当たると、弁体５が出口側に動けなくなるので、ダイアフラム４に取り付けられている弁座Ａ１５はバネＡ２１を撓ませて弁Ａ１８を離れ出口側に動き図４の如くに開弁して流体を出口８に流出する。
【００３０】
逆圧が発生した場合には、ダイアフラム４が中間室１１と二次室１２の差圧により入口側に動き、バネＡ２１により弁座Ａ１５が弁Ａ１８に当接して閉弁し、さらに弁座Ａ１５と弁Ａ１８が閉弁した状態で入口側に動くと、弁Ｂ２４が弁座Ｂ２３に当接して図３に示す如くに閉弁して二重の開閉機構を構成する。さらにダイアフラム４に差圧力が加わると弁座Ａ１５を弁Ａ１８に圧接すると同時に弁Ｂ２４を弁座Ｂ２３に圧接しシール力を増加する。また、図１１に示すように、ダイアフラム４の二次室側と出口ハウジング２の間にバネＢ２６を付勢させることもある。
【００３１】
図９は本発明を実施する減圧式逆流防止器の縦断面図であり、Ａはハウジング、１はハウジングＡの入口７を具備する前述複式逆止弁の実施例の入口ハウジング１の側面に第二圧力室３３を形成した入口ハウジング、２はハウジングＡの出口８を具備する出口ハウジング、３はダイアフラム４に弁体５、弁座金具６等を組み付けたダイアフラムＡＳＳＹ、３４はダイアフラムＢ２９に弁体Ｃ３５を組み付けたダイアフラムＡＳＳＹＢ、３６はダイアフラムＡＳＳＹＢの固定と第一圧力室３７を形設する圧力室蓋であり、入口ハウジング１と出口ハウジング２によりダイアフラムＡＳＳＹ３を水密に狭持しネジ（図示せず）により結合し、入口ハウジング１の側面の第二圧力室３３の外端面にダイアフラムＡＳＳＹＢ３４を圧力室蓋３６により水密に狭持しネジ（図示せず）により結合することで組み付けられている。
【００３２】
入口ハウジング１は入口７と、入口７の他端面にダイアフラム４を水密に狭持するための鍔９と内腔に中間室１１を設け、入口７と中間室１１とを結ぶ流路の中間室入口周囲に鍔９と中心軸を同じにして、弁座Ｂ２３を形成した入口ハウジング１の側面にダイアフラムＢ２９を水密に狭持するための鍔３８と内腔に第二圧力室３３を形成して、第二圧力室３３と中間室１１を連通する連通孔Ｂ３９を形設すると共に入口７と弁座Ｂ２３の間の一次室２５を圧力室蓋３６に形設される第一圧力室３７と連通するための連通孔Ａ４０を前述の鍔３８の一部を幅広にした部分に開口し、第二圧力室３３の軸心底部に外部排出口４１と連通する連通孔３０を開口し、その開口の第二圧力室側周囲に弁座Ｃ３１が形成してある。
【００３３】
圧力室蓋３６は第一圧力室３７にあたる凹部の外端面にダイアフラムＢ２９を水密に狭持するための鍔４２を形成して前述の連通孔Ａ４０の開口と対応する鍔４２の一部を幅広として、該開口に合う穴４３を形成し、一次室２５と第一圧力室３７が連通するようにしてある。
【００３４】
ダイアフラムＡＳＳＹＢ３４は外周縁部に前述の穴４３に対応する透孔４４を形成した狭持部を設けたダイアフラムＢ２９の中心部位に弁座Ｃ３１に対向する弁Ｃ３２が形成してある。弁Ｃ３２を別体に形成してダイアフラムＢ２９に一体的に取り付けても支障無い。
【００３５】
出口ハウジング２及びダイアフラムＡＳＳＹ３については前述の複式逆止弁と変わりない。
【００３６】
入口ハウジング１にダイアフラムＡＳＳＹ３を弁体５が入り口ハウジング側としてセットし、出口ハウジング２を載せてネジ（図示せず）で結合することで組み立て、入口ハウジング１の側面の第二圧力室３３の外端面にダイアフラムＡＳＳＹＢ３４を弁Ｃ３２が第二圧力室側とし、連通孔Ａ４０の開口と外周縁部の透孔４４を合わせセットして、圧力室蓋３６を前述の透孔４４に圧力室蓋３６の穴４３を合わせ一次室２５と第一圧力室３７を連通する連通孔Ａ４０を形成して載せネジ（図示せず）で結合することで組み立てる。
【００３７】
複式逆止弁部分については前述の複式逆止弁と変わらないので省略し、その他の部分の作動について説明する。入口７から流入した流体は流路を経て一次室２５に入り、弁Ｂ２４を弁座Ｂ２３から押し離し開弁して中間室１１に入り、ダイアフラム４と弁座Ａ１５にバネＡ２１で付勢された弁体５を出口側に押し動かし、弁体５の弁軸１９先端が出口ストッパー１４に突き当たると、ダイアフラム４に取り付けられている弁座Ａ１５はバネＡ２１を撓ませて弁Ａ１８を離れ出口側に動き、開弁して流体は出口に流出することは前述の複式逆止弁と変わりなく、入口７と弁座Ｂ２３の間の一次室２５の圧力が連通孔Ａ４０を通り第一圧力室３７を加圧すると共に、中間室１１の圧力が連通孔Ｂ３９を通り第二圧力室３３を加圧するので、ダイアフラムＢ２９は一次室２５（第一圧力室３７）の圧力と中間室１１（第二圧力室３３）の圧力の差圧によって軸方向に動く。
【００３８】
一次室２５の圧力が中間室１１の圧力より高いとダイアフラムＢ２９は第二圧力室側に動きダイアフラムＢ２９の第二圧力室側に形成された弁Ｃ３２を外部排出口４１と連通する連通孔Ａ３０の開口に形成した弁座Ｃ３１に圧接して閉弁して第二圧力室３３（中間室１１）と外部排出口４１を遮断する（図１０）。一次室２５の圧力が中間室１１の圧力より低い（逆圧）とダイアフラムＢ２９は第一圧力室側に動き弁Ｃ３２を弁座Ｃ３１から離し開弁させ第二圧力室３３（中間室１１）を外部排出口４１に連通する（図９）。
【００３９】
正常の流れでは一次室２５の圧力と中間室１１の圧力は弁Ｂ２４を押し開けるために要する圧力損失だけ一次室２５の圧力が高い。図１１に示す実施例はダイアフラム４の二次室側と出口ハウジング２の間にバネＢ２６を付勢させて圧力損失を大きくして一次室２５の圧力と中間室１１の圧力の圧力差を大きくした複式逆止弁の例で、同様の方法を減圧式逆流防止器にも用いることがある。又実施例では中間室１１と第二圧力室３３を連通孔Ｂ３９により連通させ、一次室２５の圧力と中間室１１の圧力の差圧によって、弁Ｃ３２を開閉させたが、二次室１２と第二圧力室３３を連通孔により連通させ、一次室２５の圧力と二次室１２の圧力の差圧によって、弁Ｃ３２を開閉させてもよい。又ダイアフラムＢ２９の第一圧力室側又は第二圧力室側とハウジングの間にバネ（図示せず）を付勢させて弁Ｃ３２の閉弁を補助する又は開弁を補助することも出来る。
【００４０】
図７は弁体５の変形例の拡大縦断面図である。前述複式逆止弁の実施例の、弁金具１７に弁Ａ１８と弁Ｂ２４を弁軸１９により固定した弁体５に替えて、弁体５を弁座Ａ１５に密着する面に弾性体から成る弁Ａ１８を形成した弁体Ａ４５と弁座Ｂ２３に密着する面に弾性体から成る弁Ｂ２４を形成した弁体Ｂ４６に分離して、弁体Ａ４５に対して弁体Ｂ４６が設定した距離軸方向に可動に組み付け、弁体Ａ４５と弁体Ｂ４６の間にバネＣ４７を付勢させて、弁体Ａ４５に対して弁体Ｂ４６を軸方向に自由度を持たせてものであり、図７の例では弁体Ａ４５の下方に延長した軸４８に水密に摺動可能に弁体Ｂ４６を嵌挿して、軸４８の端面にプッシュナット４９を嵌め、弁体Ｂ４６の移動距離を規制して、弁体Ａ４５と弁体Ｂ４６の間にバネＣ４７を付勢させてある。
弁体Ａ４５には弁体Ａ４５の入口側への移動距離を制限する弁体Ａストッパーとして弁Ｂ２４が弁座Ｂ２３に当接してから、弁体Ａ４５が０．１ｍｍ〜３ｍｍ動いた後ハウジングに突き当たる支持板５０を延設してある。
【００４１】
入口７から流入した流体は流路を経て一次室２５に入り、一次室２５と中間室１１の差圧で弁体Ｂ４６をバネＣ４７に対抗して押し動かし、弁座Ｂ２３から弁Ｂ２４を離し開弁して中間室１１に入り、中間室１１と二次室１２の差圧によりダイアフラム４と弁座Ａ１５にバネＡ２１で付勢された弁体Ａ４５を出口側に押し動かす。弁体Ｂ４６が軸４８の端面のプッシュナット４９に当たると弁体Ａ４５と弁体Ｂ４６は一体的となりダイアフラム４と共に出口側に動く。弁体Ａ４５の弁軸１９先端が出口ストッパー１４に突き当たると、弁体Ａ４５が出口側に動けなくなるので、ダイアフラム４に取り付けられている弁座Ａ１５はバネＡ２１を撓ませて弁Ａ１８を離れ出口側に動き開弁して流体は出口に流出する。
【００４２】
出口側の圧力が入口側圧力より高い逆圧が発生すると、中間室１１と二次室１２の差圧により、ダイアフラム４が入口側に動き、バネＡ２１により弁座Ａ１５が弁Ａ１８に当接して閉弁し、さらに弁座Ａ１５と弁Ａ１８が閉弁した状態で入口側に動く。弁体Ａ４５と一体的に動いた弁体Ｂ４６が弁座Ｂ２３に当接すると弁体Ａ４５はバネＣ４７を撓ませて０．１ｍｍ〜３ｍｍ動き弁体Ａ４５に延設された弁体Ａストッパーである支持板５０がハウジングに突き当たることで止まる。弁Ｂ２４を弁座Ｂ２３に圧接する力はバネＣ４７の付勢力と弁Ｂ２４に加わる一次室２５と中間室１１の差圧となる。
【００４３】
以上説明したように、本発明による逆止弁は弁座Ａをハウジングと分離し、ハウジングに対し可動する感圧盤に形成して、その弁座Ａに対して弁Ａを対向させて弁体を付勢し、該弁体の出口側への動きを制限する出口ストッパー及び入口側への動きを制限する入口ストッパーを設け、弁体が出口ストッパーに突き当たることで開弁させ、弁体が入口ストッパー当たることで感圧盤に係る流体の差圧が弁の閉弁力として加わるのでるので、差圧を感知する感圧盤と流体を開閉する弁が別体となり、感圧盤の径と弁を付勢する力の兼ね合いにより流量抵抗、弁のシール力を決定できると共にシール力の高い逆止弁となる。さらに中間室の入口に固定の弁座Ｂを設け前記弁体に弁座Ｂに対抗する弁Ｂを付帯して、感圧盤に付勢されて感圧盤をと一体で動く弁体（弁Ｂ）により開閉する開閉機構を形成することで複式逆止弁とするのであるから、弁座が動く開閉機構と弁座を固定した開閉機構の組み合わせとなり、異なる構造の逆止弁の組み合わせで信頼性の高い複式逆止弁となる。さらに前述の複式逆止弁を利用した減圧式逆流防止器とすることで複式逆止弁同様信頼性の高い減圧式逆流防止器となる。
【図面の簡単な説明】
【図１】本発明を実施する逆止弁の縦断面図
【図２】同上逆止弁の開弁時の縦断面図
【図３】本発明を実施する複式逆止弁の縦断面図
【図４】同上複式逆止弁の開弁時の縦断面図
【図５】従前の逆止弁の縦断面図
【図６】従前の複式逆止弁の縦断面図
【図７】弁体の他の実施例を示す拡大縦断面図
【図８】同上弁体の開弁時の拡大縦断面図
【図９】本発明を実施する減圧式逆流防止器の縦断面図
【図１０】同上減圧式逆流防止器の開弁時の縦断面図
【図１１】本発明を実施する複式逆止弁の他の実施例を示す縦断面図
【図１２】従前の減圧式逆流防止器の縦断面図
【符号の説明】
Ａ―――ハウジング１―――入口ハウジング２―――出口ハウジング
３―――ダイアフラムＡＳＳＹ４―――ダイアフラム５―――弁体
７―――入口８―――出口１１―――中間室１２―――二次室
１３―――入口ストッパー１４―――出口ストッパー１５―――弁座Ａ
１８―――弁Ａ１９―――弁軸２１―――バネＡ
２３―――弁座Ｂ２４―――弁Ｂ２５―――一次室
２７―――第一逆止弁２８―――第二逆止弁２９―――ダイアフラムＢ
３１―――弁座Ｃ３２―――弁Ｃ３３―――第二圧力室
３４―――ダイアフラムＡＳＳＹＢ３５―――弁体Ｃ３６―――圧力室蓋
３７―――第一圧力室３９―――連通孔Ｂ４０―――連通孔Ａ
４１―――外部排出口４５―――バネＣ４８―――軸
４９―――プッシュナット５０―――支持板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a check valve that is attached to piping, a device, or the like that supplies a fluid to prevent a back flow of the fluid. In particular, a check valve that prevents backflow of equipment used directly connected to the tap water pipe, Double check valve And a decompression type backflow preventer for use in a directly connected water supply apparatus.
[0002]
[Prior art]
A check valve in a fluid, particularly in a water supply and hot water supply system, is a valve that prevents a back flow that causes contamination of the entire water supply and hot water supply system, and is one of the most important components. As shown in FIG. 5, the conventional check valve has a valve seat 15 formed in a flow path connecting the inlet 7 and the outlet 8 of the housing A, and a surface that comes into close contact with the valve seat 15 from the outlet side is made of an elastic body. A valve body 5, which is a valve 18, is detachably mounted, and is always urged against the valve seat 15 by a spring 21, and the valve is driven by a differential pressure between the fluid pressure of the fluid flowing in from the inlet 7 and the fluid pressure on the outlet side. When the force that pushes 18 exceeds the spring force, the valve opens and the fluid flows out in the outlet direction, and the force pushing the valve 18 due to the differential pressure is less than the spring force (the inlet side fluid pressure is lower than the outlet side fluid pressure). In this case, the valve is closed to stop the flow of fluid and prevent backflow.
[0003]
Furthermore, there is a double check valve as a valve that reliably prevents backflow. Traditional Double check valve As shown in FIG. 6, two sets of the aforementioned check valves are incorporated as a first check valve 27 and a second check valve 28 in the flow path connecting the inlet 7 and the outlet 8 of the housing A.
[0004]
FIG. 12 shows a conventional decompression type backflow preventer. A conventional decompression type backflow preventer is provided with two sets of the above-described check valves as a first check valve 27 and a second check valve 28 in the flow path connecting the inlet 7 and the outlet 8 of the housing A, A primary chamber 25 between the inlet 7 upstream of the one check valve 27 and the first check valve 27; an intermediate chamber 11 between the first check valve 27 and the second check valve 28; A flow path is separated into the secondary chamber 12 between the valve 28 and the outlet 8, and a movable diaphragm B29 is assembled in a watertight manner by sensing the differential pressure between the primary chamber 25 and the intermediate chamber 11. A valve C32 facing the valve seat C31 formed around the second pressure chamber side of the opening of the communication hole 30 communicating with the second pressure chamber 33 communicating with the chamber 11 through the communication hole B39 and the external discharge port 41 is integrally formed. When the pressure in the primary chamber 25 is higher than the pressure in the intermediate chamber 11, the valve C32 is in close contact with the valve seat C31 to close the valve. When the pressure in the intermediate chamber 11 becomes higher than the pressure in the primary chamber 25, the valve is opened to open the intermediate chamber 11 to the external discharge port 41, and by any chance, the first check valve 27, the second check valve This is a device that prevents backflow even when a leak occurs in 28.
[0005]
[Problems to be solved by the invention]
The check valve is required to have a low flow resistance and a high backflow prevention capability (sealing force). Conventional check valve

Then, the flow resistance decreases, but the sealing force decreases. When F is increased, the sealing force increases, but the flow resistance increases and conflicts. Therefore, the sealing force is determined within the allowable range of flow resistance.
[0006]
The double check valve has the same problem because it uses two sets of the check valves described above, and the combination of check valves of the same structure is likely to cause the same failure, and the check valves of different structures are used. A combination of valves is desired. The same applies to a decompression type backflow preventer that uses two sets of check valves. A double check valve that combines a check valve with a low flow resistance and a high backflow prevention capability and a check valve with a different structure is desired.
[0007]
[Means for Solving the Problems]
In the conventional check valve, a valve seat integrated with the housing is formed in the flow path connecting the inlet and the outlet of the housing as in the example of FIG. Since the valve moves and closes and closes the valve seat and opens and closes the flow, the valve that opens and closes the fluid also functions as a pressure-sensitive panel that detects the differential pressure. There is a conflict between making it smaller and increasing the valve sealing force.
[0008]
In the present invention, a water chamber is formed in a flow path connecting the inlet and the outlet of the housing, and the water chamber is watertightly divided into an intermediate chamber and a secondary chamber from the inlet side, and is movable in the axial direction. A pressure-sensitive plate with a through hole communicating with the intermediate chamber and the secondary chamber is installed at the site, and a valve seat A is formed around the intermediate chamber side of the through-hole of the pressure-sensitive plate. A valve body made of an elastic body is formed on a surface of the valve body that is in close contact with the valve seat A, and the valve A is made of an elastic body so that the valve A is always in close contact with the valve seat A and is closed. The body is urged by the biasing means, and an inlet stopper that limits the movement distance of the valve body to the inlet side and an outlet stopper that restricts the movement distance of the valve body to the outlet side are provided, and the pressure-sensitive disc moves to the outlet side. When the valve element hits the outlet stopper, the valve seat A leaves the valve A and opens, and when the pressure sensitive plate moves to the inlet side, the valve element hits the inlet stopper, and the pressure sensitive plate Differential pressure of the fluid is in the check valve serving as a force of pressing the valve seat A valve A applied.
[0009]
When the inlet-side fluid pressure is higher than the outlet-side fluid pressure (normal state), the inflowing fluid pushes and moves the pressure-sensitive disc and the valve body urged by the urging means to the valve seat A of the pressure-sensitive disc. When the valve element hits an outlet stopper that restricts the movement of the valve element to the outlet side, the valve element cannot move to the outlet side, and only the pressure-sensitive disc moves, and the valve seat of the pressure-sensitive disc leaves the valve A and opens. When the inlet side fluid pressure is lower than the outlet side fluid pressure (reverse pressure state), the valve body urged by the urging means to the valve seat A of the pressure sensitive plate and the pressure sensitive plate by the outlet side fluid pressure is in a closed state. It is pushed to the entrance side. When the valve element hits an inlet stopper that restricts the movement of the valve element toward the inlet side, the differential pressure applied to the pressure sensing plate in addition to the urging force for urging the valve element presses the valve seat A against the valve A and increases the sealing force.
[0010]
As described above, by separating the valve seat from the housing and forming a pressure-sensitive disc that can move relative to the housing, the pressure-sensitive disc that senses the differential pressure and the valve that opens and closes the fluid are separated, reducing the flow resistance. It is possible to achieve both improvement and sealing power.
[0011]
In the invention according to claim 2, a water chamber is formed in a flow path connecting the inlet and the outlet of the housing, and the water chamber is partitioned watertightly into an intermediate chamber and a secondary chamber from the inlet side in the water chamber. A pressure-sensitive disc with a through hole communicating with the intermediate chamber and the secondary chamber in the axial center is installed, and a valve seat A is formed around the intermediate chamber side of the through-hole of the pressure-sensitive disc. The valve seat B is formed integrally or integrally with the housing around the inlet of the intermediate chamber in the flow path connecting the intermediate seat and the intermediate chamber, and the intermediate seat between the valve seat A and the valve seat B is in close contact with the valve seat A The valve A made of an elastic body and the valve body formed of the elastic body B are assembled on the surfaces close to the valve A and the valve seat B, the valve A is made to face the valve seat A, and the valve B is made to face the valve seat B. The valve body is urged by the urging means so that A is in close contact with the valve seat A, and an outlet stopper is provided to limit the moving distance of the valve body to the outlet side, and the pressure-sensitive disc moves to the outlet side. When the valve body hits the outlet stopper, a valve seat A is opened leaving the valve A, sensitive platens valve body moves to the inlet side valve B Moving to the inlet side to close the contact passages to the valve seat B Double check valve It has become.
[0012]
When the inlet side fluid pressure is higher than the outlet side fluid pressure (normal state), the inflowing fluid pushes and moves the pressure sensing plate and the valve body A urged by the urging means to the valve seat A of the pressure sensing plate to the outlet side. Release valve B from B and open. When the valve body further moves to the outlet side and hits the outlet stopper that restricts the movement of the valve body to the outlet side, the valve body cannot move to the outlet side, only the pressure plate moves, and the valve seat A of the pressure plate moves the valve A. Open away.
[0013]
When the inlet-side fluid pressure is lower than the outlet-side fluid pressure (reverse pressure state), the valve body urged by the urging means to the pressure-sensitive disc and the valve seat A of the pressure-sensitive disc by the outlet-side fluid pressure is in the closed state The valve B of the valve element hits the valve seat B and closes, and the differential pressure applied to the pressure sensing plate in addition to the urging force for urging the valve element presses the valve seat A against the valve A and Press against B to increase sealing force.
[0014]
Therefore, the opening / closing mechanism by one valve seat A and the valve A of the double check valve opens and closes when the valve seat formed on the pressure sensing plate is closely attached to the valve, and the opening / closing mechanism by the valve seat B and valve B is opened in the housing. Since it operates as a check valve that opens and closes when the valve is in close contact with the formed valve seat, it becomes a double check valve that combines check valves with different structures.
[0015]
According to a third aspect of the present invention, there is provided a pressure reducing type backflow preventer comprising two sets of conventional check valves as a first check valve and a second check valve mounted on a flow path connecting an inlet and an outlet of a housing. A primary chamber between the inlet upstream of the check valve and the first check valve, an intermediate chamber between the first check valve and the second check valve, and a secondary chamber between the second check valve and the outlet In place of separating the flow path, the above-mentioned double check valve is mounted, and the open / close mechanism by the valve seat B and valve B of the double check valve is the first check valve, the open / close mechanism by the valve seat A and the valve A Is separated into a primary chamber, an intermediate chamber, and a secondary chamber as a second check valve, so that the same effect as the above-described double check valve is obtained, and a highly safe decompression type backflow preventer is obtained.
[0016]
In the invention according to claim 4, the valve body is formed with a valve body A formed of an elastic body on a surface in close contact with the valve seat A, and a valve B formed of an elastic body on a surface in close contact with the valve seat B. The valve body B is separated from the valve body B and is movably assembled in the distance axis direction set by the valve body B with respect to the valve body A so that the valve body A and the valve body B are separated between the valve body A and the valve body B. The valve body A is 0.1 mm toward the inlet side after the valve B abuts the valve seat B with a valve body A stopper that urges the biasing means to limit the moving distance of the valve body A to the inlet side. Because it was installed at a position where it stops after moving 3mm,
[0017]
The valve body B is pushed away from the valve seat B to open the valve because the product of the difference between the primary chamber pressure and the intermediate chamber pressure of the fluid flowing in from the inlet and the area of the valve B is between the valve body A and the valve body B. When the urging force that has been urged is overcome and the counter pressure state is reached, the valve body A and the valve body B move integrally until the valve B contacts the valve seat B, and the valve B contacts the valve seat B. Then, the valve element A moves 0.1 mm to 3 mm against the urging force urged between the valve element A and the valve element B, presses the valve B against the valve seat B, and stops against the valve element A stopper. The force that presses the valve B against the valve seat B is the difference between the urging force urged between the valve body A and the valve body B, the primary chamber pressure, and the intermediate chamber pressure. The check valve is not related to the valve body A urged by the urging means on the pressure plate and the pressure sensitive plate. Other operations are the same as those of the double check valve.
[0018]
【Example】
Next, embodiments will be described in detail with reference to the drawings. In addition, the same code | symbol shall be used about a drawing member code | symbol about the same member as the thing of a conventional means.
[0019]
FIG. 1 is a longitudinal sectional view of a check valve having a diaphragm type pressure-sensitive disc for carrying out the present invention, in which A is a housing, 1 is an inlet housing having an inlet 7 of the housing A, and 2 is a housing A. An outlet housing 3 having an outlet 8 is a diaphragm ASSY that serves as a pressure-sensitive panel in which a valve body 5 and a valve seat bracket 6 are assembled to the diaphragm 4. The diaphragm ASSY 3 is sandwiched between the inlet housing 1 and the outlet housing 2 in a watertight manner. It is assembled by connecting with an internal screw (not shown).
[0020]
The inlet housing 1 is provided with an inlet 7, a flange 9 for watertightly holding the diaphragm 4 on the other surface of the inlet 7, an intermediate chamber 11 in the inner cavity, and an intermediate of a flow path connecting the inlet 7 and the intermediate chamber 11. In the vicinity of the chamber, an inlet stopper 13 for limiting the moving distance of the valve body 5 to the inlet side is formed in the same manner as the rod 9 and the central axis.
[0021]
The outlet housing 2 is provided with an outlet 8, a flange 10 for watertightly holding the diaphragm 4 on the other end surface of the outlet 8, and a secondary chamber 12 in the lumen, and a flow path connecting the outlet 8 and the secondary chamber 12. In the vicinity of the secondary chamber, an outlet stopper 14 for limiting the moving distance of the valve body 5 to the outlet side is formed in the same manner as the flange 9 and the central axis.
[0022]
The diaphragm ASSY 3 is provided with a valve seat metal fitting 6 provided with a hole in the central portion of the diaphragm 4 provided with a sandwiching portion on the outer peripheral edge portion, and a through hole communicating with the intermediate chamber 11 and the secondary chamber 12 in the central portion of the hole. Install it tightly with caulking. A valve seat A15 is formed around the through hole on the intermediate chamber side of the valve seat metal fitting 6, a boss 22 is formed at the center of the through hole, and the valve shaft 19 of the valve body 5 is fitted to the axial center of the boss 22. A valve body 5 in which a through-hole 16 to be inserted is formed and a valve A18 made of an elastic body is fixed to the valve fitting 17 by a valve shaft 19, and the valve of the valve body 5 is inserted into the through-hole 16 of the boss 22 from the valve seat A side. The shaft 19 is inserted and the valve A18 is assembled to face the valve seat A15, and the spring A21 is urged by the push nut 20 between the end surface of the boss 22 and the tip of the valve shaft 19, and the valve A18 is attached to the valve seat A15. It is always in a close contact state.
[0023]
Thus, the diaphragm ASSY 3 is set on the inlet housing 1 as the valve body 5 is set on the inlet housing side, and the outlet housing 2 is mounted and assembled with screws (not shown).
[0024]
Then, the fluid flowing in from the inlet 7 enters the intermediate chamber 11 through the flow path, and the valve body 5 which is in close contact with the valve seat A15 by the diaphragm 4 and the spring A21 due to the differential pressure between the intermediate chamber 11 and the secondary chamber 12 is on the outlet side. To move. When the tip of the valve shaft 19 of the valve body 5 comes into contact with the outlet stopper 14, the valve body 5 cannot move to the outlet side. Therefore, the valve seat A15 attached to the diaphragm 4 deflects the spring A21 to leave the valve A18 and exit the outlet side. Then, the valve is opened as shown in FIG.
[0025]
When a reverse pressure is generated in which the pressure on the outlet side is higher than the pressure on the inlet side, the diaphragm 4 moves to the inlet side due to the differential pressure between the intermediate chamber 11 and the secondary chamber 12, and the valve seat A15 contacts the valve A18 by the spring A21. When the valve is closed and the valve seat A15 and the valve A18 are closed, the valve moves toward the inlet side, the inlet side end of the valve body 5 hits the inlet stopper 13, and the valve body 5 stops as shown in FIG. The force with which the seat A15 presses against the valve A18 adds the force of the differential pressure related to the diaphragm 4 to the biasing force of the spring A21 to increase the sealing force.
[0026]
FIG. 3 is a longitudinal sectional view of a double check valve embodying the present invention. The inlet housing 1 is provided with an inlet 7, a flange 9 for watertightly holding the diaphragm 4 on the other end surface of the inlet 7, an intermediate chamber 11 in the inner cavity, and an intermediate chamber of a flow path connecting the inlet 7 and the intermediate chamber 11. In the vicinity, the valve seat B is formed with the same center axis as the flange 9. The outlet housing 2 is the same as the outlet housing 2 of the aforementioned check valve.
[0027]
The diaphragm ASSY 3 is provided with recesses for incorporating a valve made of an elastic body on both surfaces of the valve fitting 17 of the valve body 5, a valve A 18 facing the valve seat A 15 on one surface and a valve B 24 facing the valve seat B 23 on the other surface. Except for the valve body 5 which is fixed from the valve A side by the valve shaft 19, it is the same as the above-described check valve diaphragm ASSY3.
[0028]
The assembly of the diaphragm assembly 3 by setting the diaphragm ASSY 3 on the inlet housing 1 as the inlet housing side and mounting the outlet housing 2 with screws (not shown) is the same as the above-described check valve embodiment.
[0029]
The fluid flowing from the inlet 7 passes through the flow path and enters the primary chamber 25 between the inlet 7 and the valve seat B23, and is attached to the valve seat A15 by the diaphragm 4 and the spring A21 due to the differential pressure between the primary chamber 25 and the intermediate chamber 11. The urged valve body 5 is pushed and moved, the valve B24 is pushed away from the valve seat B23 and opened to enter the intermediate chamber 11, and due to the differential pressure between the intermediate chamber 11 and the secondary chamber 12, the diaphragm 4 and the spring A21 The valve body 5 brought into close contact with the seat A15 is moved to the outlet side. When the tip of the valve shaft 19 of the valve body 5 comes into contact with the outlet stopper 14, the valve body 5 cannot move to the outlet side. Therefore, the valve seat A15 attached to the diaphragm 4 deflects the spring A21 to leave the valve A18 and exit the outlet side. Then, the valve is opened as shown in FIG.
[0030]
When reverse pressure is generated, the diaphragm 4 moves to the inlet side due to the differential pressure between the intermediate chamber 11 and the secondary chamber 12, the valve seat A15 contacts the valve A18 by the spring A21, and the valve seat A15 is further closed. When the valve A18 moves to the inlet side with the valve closed, the valve B24 contacts the valve seat B23 and closes as shown in FIG. 3 to form a double opening / closing mechanism. Further, when a differential pressure is applied to the diaphragm 4, the valve seat A15 is pressed against the valve A18 and simultaneously the valve B24 is pressed against the valve seat B23 to increase the sealing force. Further, as shown in FIG. 11, the spring B <b> 26 may be biased between the secondary chamber side of the diaphragm 4 and the outlet housing 2.
[0031]
FIG. 9 is a longitudinal sectional view of a pressure reducing type backflow preventer embodying the present invention. A is a housing, and 1 is a side view of the inlet housing 1 of the embodiment of the double check valve having the inlet 7 of the housing A. An inlet housing having two

pressure chambers

33, 2 is an outlet housing having an outlet 8 of housing A, 3 is a diaphragm 4 having a valve body 5 attached to a diaphragm 4, a valve seat bracket 6 and the like, and 34 is a valve body to a diaphragm B29. Diaphragms ASSYB and 36 assembled with C35 are pressure chamber lids for fixing the diaphragm ASSYB and forming the first pressure chamber 37. The diaphragm ASSY3 is held in a watertight manner by the inlet housing 1 and the outlet housing 2 (not shown). ) And a diaphragm ASSYB 34 is attached to the outer end surface of the second pressure chamber 33 on the side surface of the inlet housing 1 by a pressure chamber lid 36. It is assembled by coupling the tightly clamped by screws (not shown).
[0032]
The inlet housing 1 is provided with an inlet 7, a flange 9 for watertightly holding the diaphragm 4 on the other end surface of the inlet 7, an intermediate chamber 11 in the inner cavity, and an intermediate chamber of a flow path connecting the inlet 7 and the intermediate chamber 11. The central axis is the same as that of the flange 9 around the inlet, and the second pressure chamber 33 is formed in the lumen and the flange 38 for watertightly holding the diaphragm B29 on the side surface of the inlet housing 1 where the valve seat B23 is formed. A communication hole B39 for communicating the second pressure chamber 33 and the intermediate chamber 11 is formed, and the primary chamber 25 between the inlet 7 and the valve seat B23 is communicated with the first pressure chamber 37 formed in the pressure chamber lid 36. A communication hole A40 is opened in a part where the part of the flange 38 is widened, and a communication hole 30 communicating with the external discharge port 41 is opened at the bottom of the axial center of the second pressure chamber 33. A valve seat C31 is formed around the second pressure chamber.
[0033]
The pressure chamber lid 36 is formed with a flange 42 for watertightly holding the diaphragm B29 on the outer end surface of the recess corresponding to the first pressure chamber 37, and a part of the flange 42 corresponding to the opening of the communication hole A40 is widened. A hole 43 that fits the opening is formed so that the primary chamber 25 and the first pressure chamber 37 communicate with each other.
[0034]
The diaphragm ASSYB 34 is formed with a valve C32 facing the valve seat C31 at a central portion of the diaphragm B29 provided with a holding portion in which a through hole 44 corresponding to the aforementioned hole 43 is formed on the outer peripheral edge. There is no problem even if the valve C32 is formed separately and attached to the diaphragm B29 integrally.
[0035]
The outlet housing 2 and the diaphragm ASSY 3 are the same as the above-described double check valve.
[0036]
A diaphragm ASSY 3 is set on the inlet housing 1 as a valve body 5 on the inlet housing side, and the outlet housing 2 is mounted and connected by screws (not shown), and is assembled outside the second pressure chamber 33 on the side of the inlet housing 1. At the end face, the diaphragm ASSYB 34 is set to the second pressure chamber side with the valve C 32, the opening of the communication hole A 40 and the through hole 44 of the outer peripheral edge are set together, and the pressure chamber cover 36 is inserted into the above-described through hole 44. The holes 43 are combined to form a communication hole A40 that allows the primary chamber 25 and the first pressure chamber 37 to communicate with each other, and the assembly is performed by connecting with mounting screws (not shown).
[0037]
Since the double check valve portion is the same as the double check valve described above, the description thereof will be omitted, and the operation of other portions will be described. The fluid flowing in from the inlet 7 enters the primary chamber 25 through the flow path, pushes the valve B24 away from the valve seat B23, opens the valve, enters the intermediate chamber 11, and is urged by the spring A21 to the diaphragm 4 and the valve seat A15. When the valve body 5 is pushed to the outlet side and the tip of the valve shaft 19 of the valve body 5 hits the outlet stopper 14, the valve seat A15 attached to the diaphragm 4 deflects the spring A21 and leaves the valve A18 to the outlet side. It moves, opens, and the fluid flows out to the outlet as in the above-described double check valve. The pressure in the primary chamber 25 between the inlet 7 and the valve seat B23 passes through the communication hole A40 and passes through the first pressure chamber 37. In addition to pressurization, the pressure in the intermediate chamber 11 passes through the communication hole B39 and pressurizes the second pressure chamber 33, so that the diaphragm B29 is in contact with the pressure in the primary chamber 25 (first pressure chamber 37) and the intermediate chamber 11 (second pressure chamber 33). ) Shaft by pressure differential pressure Move in direction.
[0038]
When the pressure in the primary chamber 25 is higher than the pressure in the intermediate chamber 11, the diaphragm B29 moves to the second pressure chamber side and the valve C32 formed on the second pressure chamber side of the diaphragm B29 is turned on. External outlet 41 The second pressure chamber 33 (intermediate chamber 11) and the external discharge port 41 are shut off by pressure-contacting and closing the valve seat C31 formed at the opening of the communication hole A30 that communicates with (FIG. 10). When the pressure in the primary chamber 25 is lower than the pressure in the intermediate chamber 11 (reverse pressure), the diaphragm B29 moves to the first pressure chamber side, opens the valve C32 away from the valve seat C31, and opens the second pressure chamber 33 (intermediate chamber 11). It communicates with the external outlet 41 (FIG. 9).
[0039]
Under normal flow, the pressure in the primary chamber 25 and the pressure in the intermediate chamber 11 are higher than the pressure in the primary chamber 25 by the pressure loss required to open the valve B24. In the embodiment shown in FIG. 11, the spring B 26 is biased between the secondary chamber side of the diaphragm 4 and the outlet housing 2 to increase the pressure loss, thereby increasing the pressure difference between the pressure in the primary chamber 25 and the pressure in the intermediate chamber 11. In the example of the double check valve, the same method may be used for the pressure reducing type backflow preventer. In the embodiment, the intermediate chamber 11 and the second pressure chamber 33 are communicated with each other through the communication hole B39, and the valve C32 is opened and closed by the differential pressure between the pressure in the primary chamber 25 and the pressure in the intermediate chamber 11. The second pressure chamber 33 may be communicated with the communication hole, and the valve C32 may be opened and closed by a differential pressure between the pressure in the primary chamber 25 and the pressure in the secondary chamber 12. Further, a spring (not shown) may be urged between the first pressure chamber side or the second pressure chamber side of the diaphragm B29 and the housing to assist in closing the valve C32 or assist in opening the valve.
[0040]
FIG. 7 is an enlarged longitudinal sectional view of a modified example of the valve body 5. Instead of the valve body 5 in which the valve A18 and the valve B24 are fixed to the valve fitting 17 by the valve shaft 19 in the embodiment of the above-described double check valve, the valve body 5 is a valve made of an elastic material on the surface closely contacting the valve seat A15. The valve body A45 formed with A18 and the valve body B46 formed with a valve B24 made of an elastic body on the surface in close contact with the valve seat B23 are separated, and the valve body B46 is movable in the distance axis direction set by the valve body A45. The valve body B46 is biased between the valve body A45 and the valve body B46 so that the valve body B46 has a degree of freedom in the axial direction with respect to the valve body A45. In the example of FIG. A valve body B46 is fitted on a shaft 48 extending below the body A45 so as to be slidable in a watertight manner, a push nut 49 is fitted on the end surface of the shaft 48, and the moving distance of the valve body B46 is regulated, A spring C47 is biased between the valve bodies B46.
The valve body A45 hits the housing after the valve body A45 has moved 0.1 mm to 3 mm after the valve B24 has come into contact with the valve seat B23 as a valve body A stopper for limiting the moving distance of the valve body A45 to the inlet side. A support plate 50 is extended.
[0041]
The fluid flowing in from the inlet 7 enters the primary chamber 25 through the flow path, pushes the valve body B46 against the spring C47 by the differential pressure between the primary chamber 25 and the intermediate chamber 11, and releases the valve B24 from the valve seat B23. The valve enters the intermediate chamber 11, and the valve body A45 urged by the spring A21 to the diaphragm 4 and the valve seat A15 is pushed and moved to the outlet side by the differential pressure between the intermediate chamber 11 and the secondary chamber 12. When the valve body B46 hits the push nut 49 on the end face of the shaft 48, the valve body A45 and the valve body B46 are united and move together with the diaphragm 4 toward the outlet side. When the tip of the valve shaft 19 of the valve body A45 hits the outlet stopper 14, the valve body A45 cannot move to the outlet side. Therefore, the valve seat A15 attached to the diaphragm 4 deflects the spring A21 and leaves the valve A18 to leave the outlet side. The valve opens and the fluid flows out to the outlet.
[0042]
When a reverse pressure is generated in which the pressure on the outlet side is higher than the pressure on the inlet side, the diaphragm 4 moves to the inlet side due to the differential pressure between the intermediate chamber 11 and the secondary chamber 12, and the valve seat A15 contacts the valve A18 by the spring A21. The valve is closed, and further, the valve seat A15 and the valve A18 move to the inlet side with the valve closed. When the valve body B46 moved integrally with the valve body A45 comes into contact with the valve seat B23, the valve body A45 is a valve body A stopper which is extended by 0.1 mm to 3 mm by bending the spring C47. The support plate 50 stops when it hits the housing. The force that presses the valve B24 against the valve seat B23 is the urging force of the spring C47 and the differential pressure between the primary chamber 25 and the intermediate chamber 11 applied to the valve B24.
[0043]
As described above, the check valve according to the present invention separates the valve seat A from the housing and is formed on a pressure-sensitive disc movable with respect to the housing. An outlet stopper that restricts the movement of the valve body toward the outlet side and an inlet stopper that restricts the movement toward the inlet side are provided, and the valve body is opened by striking the outlet stopper. Since the pressure difference of the fluid related to the pressure sensing plate is applied as the valve closing force by hitting, the pressure sensing plate that senses the differential pressure and the valve that opens and closes the fluid are separated, and the pressure sensing plate diameter and the valve are energized. The flow resistance and the sealing force of the valve can be determined depending on the balance of the forces to be applied, and the check valve has a high sealing force. Further, a fixed valve seat B is provided at the inlet of the intermediate chamber, and the valve body is accompanied by a valve B that opposes the valve seat B, and is urged by the pressure sensing plate to move integrally with the pressure sensing plate (valve B). By forming an open / close mechanism that opens and closes with a double-check valve, it is a combination of an open / close mechanism that moves the valve seat and an open / close mechanism that fixes the valve seat. High double check valve. Further, by adopting a pressure reducing type backflow preventer using the above-mentioned double type check valve, it becomes a pressure reducing type backflow preventer having high reliability like the double type check valve.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a check valve embodying the present invention.
FIG. 2 is a longitudinal sectional view when the check valve is opened.
FIG. 3 is a longitudinal sectional view of a double check valve embodying the present invention.
FIG. 4 is a longitudinal sectional view of the above-described double check valve when opened.
FIG. 5 is a longitudinal sectional view of a conventional check valve.
FIG. 6 is a longitudinal sectional view of a conventional double check valve.
FIG. 7 is an enlarged longitudinal sectional view showing another embodiment of the valve body.
FIG. 8 is an enlarged longitudinal sectional view when the valve body is opened.
FIG. 9 is a longitudinal sectional view of a pressure reducing type backflow preventer embodying the present invention.
FIG. 10 is a longitudinal sectional view of the decompression type backflow preventer when the valve is opened.
FIG. 11 is a longitudinal sectional view showing another embodiment of the double check valve for carrying out the present invention.
FIG. 12 is a longitudinal sectional view of a conventional decompression type backflow preventer.
[Explanation of symbols]
A--Housing 1--Inlet housing 2--Outlet housing
3--Diaphragm ASSY 4 --- Diaphragm 5 --- Valve
7--Inlet 8--Exit 11--Intermediate room 12--Secondary room
13--Inlet stopper 14--Outlet stopper 15 --- Valve seat A
18--Valve A 19 --- Valve shaft 21 --- Spring A
23 --- Valve seat B 24--Valve B 25--Primary chamber
27--first check valve 28--second check valve 29 --- diaphragm B
31--Valve seat C 32 --- Valve C 33 --- Second pressure chamber
34--Diaphragm ASSYB 35--Valve C 36 --- Pressure chamber lid
37--First pressure chamber 39--Communication hole B 40 --- Communication hole A
41--External outlet 45--Spring C 48--Axis
49 --- Push nut 50 --- Support plate

Claims

A water chamber is formed in the flow path connecting the inlet and outlet of the housing, and the water chamber is watertightly divided into an intermediate chamber and a secondary chamber from the inlet side, and is movable in the axial direction. A pressure-sensitive plate with a through hole communicating with the chamber and the secondary chamber is installed, and a valve seat A is formed around the intermediate chamber side of the through-hole of the pressure-sensitive plate so that the valve seat A is in close contact with the intermediate chamber side. A valve body made of an elastic body is formed on the surface of the valve body that is in contact with the valve seat A, and the valve body is attached so that the valve A always contacts the valve seat A and closes. An inlet stopper that restricts the moving distance of the valve body to the inlet side and an outlet stopper that restricts the moving distance to the outlet side are provided by the biasing means, and the pressure sensitive plate moves to the outlet side so that the valve body is the outlet stopper. The valve seat A leaves the valve A and opens, and when the pressure sensitive plate moves to the inlet side, the valve element hits the inlet stopper and the difference in fluid applied to the pressure sensitive plate Check valve to be a force for pressing the valve seat A to Chikaragaben A

A water chamber is formed in a flow path connecting the inlet and the outlet of the housing, and the water chamber is watertightly divided into an intermediate chamber and a secondary chamber from the inlet side, and is movable in the axial direction. A pressure-sensitive plate having a through hole communicating with the chamber and the secondary chamber is installed, a valve seat A is formed around the intermediate chamber side of the through hole of the pressure-sensitive plate, and a flow path connecting the inlet and the intermediate chamber side A valve seat B is formed integrally or integrally with the housing around the inlet of the intermediate chamber, and the valve A and the valve are made of an elastic material on the surface close to the valve seat A in the intermediate chamber between the valve seat A and the valve seat B. The valve body in which the valve B made of an elastic body is formed on the surface that is in close contact with the seat B, the valve A is opposed to the valve seat A, the valve B is opposed to the valve seat B, and the valve A always adheres to the valve seat A. The valve body is urged by the urging means so that the valve body is closed, and an outlet stopper is provided to limit the movement distance of the valve body to the outlet side. Strikes the valve seat A is opened leaving the valve A, double check valve sensitive platens valve body moves to the inlet side of the valve B Moving to the inlet side to close the contact passages to the valve seat B

A water chamber is formed in a flow path connecting the inlet and the outlet of the housing, and the water chamber is watertightly divided into an intermediate chamber and a secondary chamber from the inlet side, and is movable in the axial direction. A pressure-sensitive plate having a through hole communicating with the chamber and the secondary chamber is installed, a valve seat A is formed around the intermediate chamber side of the through hole of the pressure-sensitive plate, and a flow path connecting the inlet and the intermediate chamber side A valve seat B is formed integrally or integrally with the housing around the inlet of the intermediate chamber, and the valve A and the valve are made of an elastic material on the surface close to the valve seat A in the intermediate chamber between the valve seat A and the valve seat B. The valve body in which the valve B made of an elastic body is formed on the surface that is in close contact with the seat B, the valve A is opposed to the valve seat A, the valve B is opposed to the valve seat B, and the valve A always adheres to the valve seat A. The valve body is urged by the urging means so that the valve is closed, and an outlet stopper is provided to limit the moving distance of the valve body to the outlet side, and the pressure-sensitive disc moves to the outlet side and contacts the outlet stopper. That the valve seat A is opened leaving the valve A, sensitive platens valve body moves to the inlet side valve B Moving to the inlet side of the double check valve which closes the contact passages to the valve seat B Depressurization type backflow preventer constituted by opening / closing mechanism by valve seat B and valve B as first check valve and opening / closing mechanism by valve seat A and valve A as second check valve

The valve body A is separated into a valve body A in which the valve A made of an elastic body is formed on the surface closely contacting the valve seat A, and a valve body B in which the valve B made of an elastic body is formed on the surface closely contacting the valve seat B, The valve body B is assembled to the valve body A so as to be movable in the distance axis direction set, and the biasing means is biased so as to separate the valve body A and the valve body B between the valve body A and the valve body B, A valve element A stopper for limiting the distance of movement of the valve element A to the inlet side is installed at a position where the valve element A moves about 0.1 mm to 3 mm toward the inlet side and stops after the valve B comes into contact with the valve seat B. The double check valve according to claim 2 and the decompression type backflow preventer according to claim 3.