JP3795584B2

JP3795584B2 - Double seal valve

Info

Publication number: JP3795584B2
Application number: JP18488796A
Authority: JP
Inventors: 薫小澤
Original assignee: TOSTE CO.,LTD.
Current assignee: TOSTE CO.,LTD.
Priority date: 1996-07-15
Filing date: 1996-07-15
Publication date: 2006-07-12
Anticipated expiration: 2016-07-15
Also published as: JPH1030735A

Description

【０００１】
【発明の属する技術分野】
本発明は、食品製造、醸造等の機械やプラントにおける液体流通ラインに使用される二重シール弁に関するもので、流路を二重にシールすることにより二液の混合を防止する弁構造に関する。
【０００２】
【従来の技術】
この種の一般的な二重シール弁は、上部流路と下部流路との間に形成した連通路に弁座を設け、弁座の内周側に摺接係合する第１弁体を第１弁軸に、また弁座の上部側に押接係合する第２弁体を第２弁軸に設け、第１弁軸及び２弁軸を弁開閉駆動機構により適宜に駆動させることによって、第１弁体及び第２弁体が閉じた弁全閉状態と両弁体が開いた弁全開状態とを実行させるようにしたものであるが、上記弁全閉状態及び弁全開状態に加えて、第１弁体が若干開き第２弁体が閉じた弁部分開状態、または第１弁体が閉じ第２弁体が若干開いた弁部分開状態を実行させるようにしたものが、例えば特開平７−２５３１６７号公報に記載されている。
【０００３】
【発明が解決しようとする課題】
上記公報に記載の二重シール弁では、弁全閉及び弁全開状態と弁部分開状態とを実行させるための２つの弁開閉駆動機構を上下に連設しているが、上部側弁開閉駆動機構のシリンダと下部側弁開閉駆動機構のシリンダとが、第１弁軸を気密状態で挿通する隔壁を介して互いに独立して設けられ、両シリンダには、上部側のシリンダ内に上下一対のピストン、下部側のシリンダ内に１つのピストンの３つのピストンが配設され、しかも上部側シリンダ内の両ピストンとピストンロッドに対し摺動可能に設けてあることから、気密シール部が多数箇所にわたり複雑化して製作上の困難を来す上、構造のコンパクト化に難点があり、また上部側シリンダのピストンがフリー状態に設けてあるため、弁全開動作時等に引っ掛かったりして誤作動を生じる問題があった。
【０００４】
本発明は、弁開閉駆動機構の構造のコンパクト化を可能にすると共に、誤作動を生じることがなく安全に使用できる二重シール弁を提供することを課題とするものである。
【０００５】
【課題を解決するための手段】
上記の課題を解決するための請求項１に係る二重シール弁は、上部流路１と下部流路２との間に形成した連通路３に弁座６を設け、弁座６の内周側に係合する第１弁体７を第１弁軸８に、また弁座６の上部側に押接係合する第２弁体９を、第１弁軸８に摺動可能で且つ第１ばね１１により常時下向きに付勢されるように嵌装される第２弁軸１０に設けると共に、第１弁軸８を弁開閉駆動機構２８に連動連結し、開弁時に弁開閉駆動機構２８の作動による第１弁軸８の上動に伴って第２弁体９が追従移動する二重シール弁であって、弁開閉駆動機構２８は、第１弁軸８をピストンロッドとしてこれに固定したピストン２９を固定シリンダ３０内に嵌挿したエアシリンダからなり、固定シリンダ３０内の上部にばね受け３１を配置し、このばね受け３１とピストン２９との間には、このピストン２９と第２弁軸１０との間に介装される前記第１ばね１１よりばね力の大きい第２ばね３２と、前記ピストンロッドに固定され且つばね受け３１に対し伸縮自在に連結されて、第２ばね３２の伸びを一定範囲に制限するばね制限ストッパー３３とを介装し、固定シリンダ３０にはピストン２９を挟む上下両室３０ａ，３０ｂに対するエアの給排を行うエア給排ポート３４，３５を設け、上記上部室３０ａにエア供給され該上部室３０ａの圧力上昇により上記ピストン２９が下方に押されて上記第２ばね３２及びばね受け３１と共に一体に下降するようになっていることを特徴とする。
【０００６】
請求項２は、請求項１に記載の二重シール弁において、前記弁開閉駆動機構２８の下方にエアシリンダからなる第２の弁体開閉駆動機構３６を設け、この第２の弁体開閉駆動機構３６は、前記固定シリンダ３０の下部に連通して形成された第２シリンダ３７と、このシリンダ３７に内嵌されると共に第２弁軸１０に外嵌されて所定ストロークＳ１上下動する第２ピストン３８と、第２ピストン３８を下動限位置に付勢する第３ばね３９と、第２シリンダ３７の下部室３７ａに対するエアの給排を行うエア給排ポート４０とを備え、上記下部室３７ａへのエアの供給による第２ピストン３８の上動に伴い第２弁軸１０が前記第１ばね１１の付勢力に抗して上動し、第２弁体９を開放させるようになっていることを特徴とする。
【０００７】
請求項３は、請求項２に記載の二重シール弁において、第３ばね３９により下動限位置に付勢される第２ピストン３８の内周側上端部３８ｂと、第１ばね１１により閉弁位置に付勢される第２弁軸１０の所要位置に設けたストッパー４３との間に、第２ピストン３８のストロークＳ１より短い軸方向遊びＳ２を設けて、第２弁軸１０のストロークがＳ１−Ｓ２となるようにしたことを特徴とする。
【０００８】
【発明の実施の形態】
図１は、本発明に係る二重シール弁の全体をａ−ａ線で二分した下半分の縦断面図で、図２は上半分を示している。これらの図において、１は上部流路、２は下部流路で、これらの流路１，２は互いに平行または交差方向に形成されていて、両流路１，２の間には連通路３が形成され、また両流路１，２における連通路３と同軸上に対向する部位に上部開口部４及び下部開口部５が形成され、そして連通路３には弁座６が装着されている。上部流路１及び下部流路２に、それぞれ例えば飲料液または洗浄液を流通させるようになっている。
【０００９】
７は、弁座６の内周側に係合する第１弁体で、上部開口部４から連通路３を通って下部開口部５側に挿入された第１弁軸８の中間軸部８ｂの下端部に一体形成されている。この第１弁体７の下部には中空状の下部軸部８ｃが同軸一体形成され、また中間軸部８ｂの上部には上部軸部８ａが、通常はねじ結合により同軸に連設されている（図１及び図２には、中間軸部８ｂと上部軸部８ａとが一体に形成されたものとして図示している）。これら上部軸部８ａと中間軸部８ｂと下部軸部８ｃとによって第１弁軸８が形成される。
【００１０】
９は、第１弁体７の上側に位置して弁座６の上部側に上方より押接係合する第２弁体で、第１弁軸８の上部軸部８ａから中間軸部８ｂにわたって套嵌された第２弁軸１０の下端部に一体に形成されており、この第２弁軸１０は、後述するようにコイルばねからなる第１ばね１１によって常時下向きに付勢され、それにより第２弁体９を弁座６の上部側に押し付けている。尚、この第２弁軸１０は、上部軸部１０ａとこれにねじ結合された下部軸部１０ｂとからなるもので、下部軸部１０ｂの下端部に第２弁体９が形成される。
【００１１】
図３以降の図面をも参照して明らかなように、第１弁体７には、弁座６の内周側座面６ａに摺動可能に密接する主環状パッキン１２がパッキン取付用嵌合溝７ａに嵌合されて取り付けられ、第２弁体９には、弁座６の上部側座面６ｂに上方より密接する副環状パッキン１３がパッキン取付用嵌合溝９ａに嵌合されて取り付けられている。上部流路１の上部開口部４には、この上部開口部４から上方へ突出する第２弁軸１０の下部軸部１０ｂを摺動可能に支持する環状部材１４が設けられ、この環状部材１４は、ヨーク１５の基部１５ａと、これの下端部で下部軸部１０ｂに密接するパッキン１６を含んで構成される。また、下部流路２の下部開口部５には、この下部開口部５から下方へ突出する第１弁軸８の下部軸部８ｃを摺動可能に支持する環状部材１７が設けられ、この環状部材１７は、スリーブ１８の径大基部１８ａと、これの上端部で下部軸部８ｃに密接するパッキン１９を含んで構成される。
【００１２】
図１に示すように、第２弁軸１０の下部軸部１０ｂには洗浄液供給口２０が設けられ、この洗浄液供給口２０は、連通孔２１を介して、第１弁軸８の中間軸部８ｂに設けられた内部通路２２に通じ、この内部通路２２は、中間軸部８ｂの下端部に放射状に設けられた複数の洗浄液噴出孔２３に通じている。しかして、洗浄液供給口２０より洗浄液を供給すると、その洗浄液は、連通孔２１より中間軸部８ｂの内部通路２２に入り、下端部の各洗浄液噴出孔２３から、第１弁体７と第２弁体９と弁座６との間に形成される環状室２４内に噴出して、この環状室２３の内部を洗浄した後、複数の通孔２５を通って下部軸部８ｃ内部の排出路２６から外部に排出される。尚、洗浄液供給口２０には洗浄液ホース接続用の口金２７がヨーク１５の窓１５ａを通して取り付けられる。
【００１３】
また、図２を参照すると、この図において２８は、第１弁体７及び第２弁体９の開閉を司る第１の弁開閉駆動機構であり、この弁開閉駆動機構２８は、第１弁軸８の上部軸部８ａをピストンロッドとし、これに固定したピストン２９を固定シリンダ３０内に嵌装したエアシリンダからなるもので、固定シリンダ３０内の上部にばね受け３１が配置され、このばね受け３１とピストン２９との間には、このピストン２９と第２弁軸１０との間に介装された第１ばね１１よりばね力の大きいコイルばねからなる第２ばね３２と、前記ピストンロッド８ａに固定され且つ前記ばね受け３１に対し伸縮自在に連結されて、前記第２ばね３２の伸びを一定範囲に制限するばね制限ストッパー３３とが介装され、そして固定シリンダ３０には、ピストン２９を隔ててその上下両室３０ａ，３０ｂに対しエアの給排を行うエア給排ポート３４，３５が設けられている。
【００１４】
前記ばね受け３１は、第２ばね３２の一端部を受けるリング状のばね受け本体３１ｏと、これと同心状に一体形成された円筒部材３１ａとからなり、前記ばね制限ストッパー３３は、ピストンロッド（第１弁軸８の上部軸部８ａ）に外嵌されて定位置に固定されると共にばね受け３１の円筒部材３１ａに摺動可能に内嵌される円筒部材３３ａからなるもので、常時は図２に示すように、第２ばね３２の付勢力で両円筒部材３１ａ，３３ａの先端係合部が互いに係合することによって、ばね受け３１とストッパー３３とが最大に伸びた状態で連結され、それにより第２ばね３２がそれ以上伸びないように制限されている。
【００１５】
従って、この第１の弁開閉駆動機構２８によると、固定シリンダ３０のピストン２９を挟んでその上下両室３０ａ，３０ｂのいずれにも圧力エアが供給されていない時には、図２に示すように、ピストン２９と第２弁軸１０の上部軸部１０ａとの間に介装された第１ばね１１の付勢力により、第１弁軸８が上方へ、第２弁軸１０が下方へそれぞれ付勢されて、第１弁体７が主環状パッキン１２を介して弁座６の内周側座面６ａに密接係合すると共に、第２弁体９が副環状パッキン１３を介して弁座６の上部側座面６ｂに密接係合し、図３に示すような弁全閉状態となる。
【００１６】
そして、エア給排ポート３５より固定シリンダ３０の下部室３０ｂに圧力エアが供給されると、ピストン２９が第２ばね３２の付勢力に抗して上昇し、これに伴い前記ストッパー３３の円筒状部材３３ａがばね受け３１の円筒部材３１ａに対し収縮作動して、第１弁軸８が上動を開始し、その途上で第１弁体７の上端部が図４に示すように第２弁体９の内周側下部に当接し、この当接状態で第１弁体７が第２弁体９を押し上げて共上がりしながら、両弁体７，９が弁座６から上方へ離間し、しかしてピストンロッド８ａの上端側に嵌装されたストローク設定リングＲが固定シリンダ３０の上壁部３０ｃに当接することで、ピストン２９が上動限位置に至り、第１弁体７及び第２弁体９は、図５に示すような弁全開状態となる。
【００１７】
また、上記の弁全開状態において固定シリンダ３０の下部室３０ｂの圧力エアを排出させることにより、ばね受け３１が固定シリンダ３０の上壁部３０ｃに押し付けられたまま、ピストン２９が第２ばね３２の付勢力によって下降し、これに伴い第１弁軸８及び第２弁軸１０が下動して、第１弁体７及び第２弁体９は図３に示すような弁全閉状態に戻る。尚、弁全閉状態（図３参照）と弁全開状態（図５参照）でのピストン２９のストロークＳａは、固定シリンダ３０の上壁部３０ｃに当接する上記ストローク設定リングＲによって設定される。
【００１８】
また、図１及び図２に示す弁全閉状態において、エア給排ポート３４から固定シリンダ３０の上部室３０ａに圧力エアが供給されると、前記ばね制限ストッパー３３によって第２ばね３２の伸びが制限されているから、上部室３０ａの圧力上昇によりピストン２９が下方に押されて、第２ばね３２及びばね受け３１と共に一体となって下降し、それに伴い第１弁軸８が第１ばね１１に付勢力に抗して下動し、第１弁体７の主環状パッキン１２が弁座６の内周側座面６ａを下方へ摺動して離間し、図６に示すように第１弁体７のみが僅かに開いた弁部分開状態となる。このように、固定シリンダ３０の上部室３０ａに圧力エアを供給することにより、第１弁軸８を単独で下動させて、第１弁体７のみを部分開状態とすることができる。この場合、ピストン２９は、図２に示される位置から下降を開始し、後述する第２シリンダ３７の上端に当接して停止する。従って、そのストロークは同図に示すＳｂとなり、このストロークＳｂ分だけ第１弁軸８が第２弁軸１０と独立して上下動することになる。
【００１９】
前記第１の弁開閉駆動機構２８の下方には、同じくエアシリンダからなる第２の弁体開閉駆動機構３６が設けられている。この第２の弁体開閉駆動機構３６は、第１の弁開閉駆動機構２８の固定シリンダ３０下部にこれと連通して形成された第２シリンダ３７と、この第２シリンダ３７に内嵌されると共に第２弁軸１０の上部軸部１０ａに外嵌された状態で所定ストローク上下動する第２ピストン３８と、この第２ピストン３８を下動限位置に付勢するコイルばねからなる第３ばね３９と、第２ピストン３８の下部室３０ａに対するエアの給排を行うエア給排ポート４０とから構成されている。図２から分かるように、第２シリンダ３７は、前記第１弁開閉駆動機構２８の固定シリンダ３０の下端部にねじ結合により連結されていると共に、この第２シリンダ３７の上部室３７ｂと前記第１弁開閉駆動機構２８における固定シリンダ３０の下部室３０ｂとが互いに連通するように形成されている。
【００２０】
図２において、４１は第２ピストン３８の下動限位置を規制するストッパーで、第２シリンダ３７の下壁部側に形成され、また４２は第２ピストン３８の上動限位置を規制するストッパーで、第２シリンダ３７の上壁部側に形成されている。しかして、第２ピストン３８は、下動限位置規制ストッパー４１と上動限位置規制ストッパー４２との間において当該ピストン３８の外周側上端部３８ａと上動限位置規制ストッパー４２との間隔に相当するストロークＳ１を上下動するが、第３ばね３９により下動限位置に付勢された第２ピストン３８の内周側上端部３８ｂと、第１ばね１１により閉弁位置に付勢された第２弁軸１０の上部軸部１０ａに突設されたストッパー４３との間に、前記ストロークＳ１よりも短い軸方向の遊びＳ２が設けられているため、この第２ピストン３８が下動限位置から上動限位置までストロークＳ１を上動することにより、第２弁軸１０は、実際には第２ピストン３８のストロークＳ１と前記軸方向遊びＳ２との差（Ｓ１−Ｓ２）分だけ上動することになる。このように、第３ばね３９で下動限位置に付勢される第２ピストン３８の内周側上端部３８ｂと、第２ばね３２で閉弁位置に付勢される第２弁軸１０側のストッパー４３との間に、第２ピストン３８のストロークＳ１より短い軸方向遊びＳ２を設けることにより、第２ばね３２の付勢力を第２弁軸１０に対して有効に作用させて、第２弁体９を弁座６の上部側座面６ｂに確実に押接係合させることができる。
【００２１】
この第２の弁開閉駆動機構３６にあっては、図２のように第２ピストン３８が下動限位置に保持されている状態から、エア給排ポート４０より第２シリンダ３７の下部室３７ａに圧力エアが供給されると、第２ピストン３８が上動を開始するが、そのピストン３８の内周側上端部３８ｂが第２弁軸１０のストッパー４２に当たるまでは、第２弁軸１０は第２弁体９を閉じる下降位置に保持されたままである。しかして、第２弁軸１０は、第２ピストン３８の内周側上端部３８ｂがストッパー４２に当たった後、第２ピストン３８の上動に伴って押し上げられ、このピストン３８の外周側上端部３８ａが上動限位置規制ストッパー４２に当たるまで上動し、それにより図７に示すように第２弁体９のみが僅かに開いた弁部分開状態となる。また、上記下部室３７ａの圧力エアを抜くことにより、第２ピストン３８が第３ばね３９により押し下げられると共に、第２弁軸１０は第２ばね３２により下動し、第２弁体９は閉弁状態となる。
【００２２】
以上のような構成を有する二重シール弁の使用において、第１の弁開閉駆動機構２８における固定シリンダ３０の下部室３０ｂに圧力エアが供給されていない状態のときには、図１〜図３に示すように、第１弁体７が主環状パッキン１２を介して弁座６の内周側座面６ａに密接係合すると共に、第１ばね１１により押し下げる第２弁軸１０によって第２弁体９が副環状パッキン１３を介して弁座６の上部側座面６ｂに押接係合して、第１弁体７及び第２弁体９が共に閉じた弁全閉状態となり、しかして上部流路１と下部流路２とを連通する連通路３は、下部流路２側の第１弁体７と上部流路１側の第２弁体９とによって二重シールされた状態で閉塞され、上部流路１を流れる液体と下部流路２を流れる液体との混合が防止される。
【００２３】
そして、上記固定シリンダ３０の下部室３０ｂに圧力エアが供給されると、図４に示すように第１弁軸８の上動に伴って第１弁体７が第２弁体９を押し上げて共上がりしながら、両弁体７，９が弁座６から上方へ十分に離間して図５に示すような弁全開状態となり、これにより連通路３が開通し、この連通路３を介して上部流路１と下部流路２とを連通させることができる。
【００２４】
また、粘性の高い液体等のように洗浄のし難い液体を使用する時は、第１弁体７及び第２弁体９の一方を閉じ、他方を僅かに開けて、開けた方のパッキン部分を洗浄液により洗浄しながら、その洗浄液を排出する。例えば、上部流路１に高粘性の飲料水を流通させ、下部流路２に洗浄液を流通させる場合には、固定シリンダ３０の上部室３０ａに圧力エアを供給すると、上部室３０ａの圧力上昇によりピストン２９が伸びを制限されている第２ばね３２と共に下降し、それに伴い第１弁軸８が下動して、第１弁体７の主環状パッキン１２が弁座６の内周側座面６ａを下方へ摺動して離間し、図６に示すように第１弁体７のみが僅かに開いた弁部分開状態となる。しかして、下部流路２からの洗浄液は、図６の矢印で示すように、第１弁体７と弁座６との間の間隙を通って、第１弁体７と第２弁体９と弁座６との間に形成される環状室２４内に導入され、その間に第１弁体７の主環状パッキン１２部分及び環状室２の内部を洗浄し、その後第１弁軸８の下部軸部８ｃ内部の排出路２６を通って外部に排出される。
【００２５】
また、下部流路２に高粘性の飲料水を流通させ、上部流路１に洗浄液を流通させる場合には、第２の弁開閉駆動機構３６における第２シリンダ３７の下部室３７ａに圧力エアを供給すると、第２ピストン３８が上動する途上でこのピストン３８にて第２弁軸１０が押し上げられ、第２ピストン３８が所定ストロークＳ１上動することにより、第２弁軸１０が前記軸方向遊びＳ２分を差し引いたストローク（Ｓ１−Ｓ２）だけ上動して、図７に示すように第２弁体９のみが僅かに開いた弁部分開状態となる。しかして、上部流路１からの洗浄液は、図７の矢印で示すように、第２弁体９と弁座６の上部側座面６ｂとの間の間隙を通過し更に第１弁体７と第２弁体９と弁座６との間に形成される環状室２４内を巡回して、第１弁体７の副環状パッキン１３部分及び環状室２の内部を洗浄した後、第１弁軸８の下部軸部８ｃ内部の排出路２６を通って外部に排出される。
【００２６】
【発明の作用及び効果】
請求項１に係る二重シール弁は、第１弁体及び第２弁体の開閉を司る弁開閉駆動機構は、第１弁軸をピストンロッドとしてこれに固定した１つのピストンを固定シリンダ内に嵌挿したエアシリンダからなるものであって、固定シリンダ内の上部にばね受けを配置し、ばね受けと前記ピストンとの間に、ピストンと第２弁軸との間に介装される第１ばねよりばね力の大きい第２ばねと、ピストンロッドに固定され且つばね受けに対し伸縮自在に連結されて、第２ばねの伸びを一定範囲に制限するばね制限ストッパーとを介装したものであるから、固定シリンダの上下両室のいずれにも圧力エアが供給されていない時には、第１ばねにより第１弁軸が上方へ、第２弁軸が下方へそれぞれ付勢されて、第１弁体が弁座の内周側に係合すると共に、第２弁体が弁座の上部側に係合して、弁全閉状態となる。そして、固定シリンダの下部室に圧力エアが供給されると、ピストンが第２ばねの付勢力に抗して上昇し、これに伴いばね制限ストッパーがばね受けに対し収縮して、第１弁軸が上動を開始し、その途上で第１弁体が第２弁体を押し上げて共上がりしながら両弁体が弁座から上方へ離間して弁全開状態となる。上記下部室の圧力エアを抜くと、第２ばねの付勢力で第１弁軸が元の位置へ下動して、第１弁体及び第２弁体が共に閉じた弁全閉状態となる。
【００２７】
また、弁全閉状態において、固定シリンダの上部室に圧力エアが供給されると、ばね制限ストッパーによって第２ばねの伸びが制限されているから、ピストンが下方に押されて第２ばね及びばね受けと一体に下降する構成となっており、それに伴い第１弁軸が第１ばねの付勢力に抗して下動し、第１弁体のみが開いた弁部分開状態となる。かくして、固定シリンダの上部室に圧力エアを供給することにより、第１弁体が開き第２弁体が閉じた部分開状態となる。
【００２８】
従って、この発明によれば、上記弁開閉駆動機構により固定シリンダの下部室に対する圧力エアの給排を行わせることによって、弁全開状態あるいは弁全閉状態とすることができ、また固定シリンダの上部室に圧力エアを供給することによって、第１弁体が開き第２弁体が閉じた部分開状態とすることができる。しかして、この弁開閉駆動機構は、固定シリンダ内にピストンを１つだけ、しかもピストンロッドに固定して設けたものであるから、気密シール部が１箇所で済み、構造の簡素化と製作の容易化を図ることができ、またピストンが作動不良を起こすことがなく、従って弁が誤作動を生ずるようなことがない。
【００２９】
請求項２に係る発明にあっては、第１の弁開閉駆動機構の下方に第２の弁開閉駆動機構を設けたことにより、上述した請求項１の発明の作用に加え、次のような作用をする。即ち、第２ピストンが下動限位置に保持されている状態から、第２シリンダの下部室に圧力エアが供給されると、第２ピストンの上動に伴って第２弁軸が押し上げられ、第２弁体のみが開いた弁部分開状態となり、また上記下部室の圧力エアを抜くことにより、第２ピストンが第３ばねにより押し下げられ、第２弁軸が第２ばねにより下動し、第２弁体は閉弁状態となる。
【００３０】
しかして、この発明によれば、第２弁開閉駆動機構における第２シリンダは、第１弁開閉駆動機構の固定シリンダ下部に、冒頭に述べた従来装置のように隔壁を介在することなく、その固定シリンダに連通して形成されたものであるから、構造の簡略化、コンパクト化が可能となり、従って製作の容易化を図ることができる。
【００３１】
請求項３によれば、第３ばねで下動限位置に付勢される第２ピストンの内周側上端部と、第２ばねで閉弁位置に付勢される第２弁軸に設けたストッパーとの間に、第２ピストンのストロークＳ１より短い軸方向遊びを設けることにより、第２ばねの付勢力を第２弁軸に対して有効に作用させて、第２弁体を弁座の上部側に確実に押接係合させることができる。
【図面の簡単な説明】
【図１】本発明に係る二重シール弁の下半分を示す縦断面図であり、ａ−ａ線が上半分との分割線である。
【図２】同二重シール弁の上半分を示す縦断面図である。
【図３】弁全閉状態にある二重シール弁中心部を示す縦断面図である。
【図４】弁全閉状態から開弁状態に移行している状態を示す二重シール弁の中心部の縦断面図である。
【図５】弁全開状態にある二重シール弁中心部を示す縦断面図である。
【図６】第１弁体が僅かに開いた弁部分開状態を示す縦断面図である。
【図７】第２弁体が僅かに開いた弁部分開状態を示す縦断面図である。
【符号の説明】
１上部流路
２下部流路
３連通路
６弁座
７第１弁体
８第１弁軸
９第２弁体
１０第２弁軸
１１第１ばね
２８第１の弁開閉駆動機構
２９ピストン
３０固定シリンダ
３０ａ上部室
３０ｂ下部室
３１ばね受け
３２第２ばね
３３ばね制限ストッパー
３４エア給排ポート
３５エア給排ポート
３６第２の弁開閉駆動機構
３７第２シリンダ
３８第２ピストン
３９第３ばね
４０エア給排ポート[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a double seal valve used for a liquid distribution line in machinery and plants for food production, brewing, etc., and relates to a valve structure that prevents mixing of two liquids by sealing a flow path double.
[0002]
[Prior art]
A general double seal valve of this type is provided with a valve seat in a communication path formed between an upper flow path and a lower flow path, and a first valve body that is slidably engaged with the inner peripheral side of the valve seat. By providing the second valve shaft with a second valve body that presses and engages the first valve shaft and the upper side of the valve seat, and appropriately driving the first valve shaft and the second valve shaft by the valve opening / closing drive mechanism The valve fully closed state in which the first valve body and the second valve body are closed and the valve fully open state in which both valve bodies are open are executed. In addition to the valve fully closed state and the valve fully open state, For example, a valve partial open state in which the first valve body is slightly opened and the second valve body is closed, or a valve partial open state in which the first valve body is closed and the second valve body is slightly opened is executed. This is described in JP-A-7-253167.
[0003]
[Problems to be solved by the invention]
In the double seal valve described in the above publication, two valve opening / closing drive mechanisms for executing the valve fully closed and valve fully opened state and the valve partial open state are connected in the vertical direction. The cylinder of the mechanism and the cylinder of the lower side valve opening / closing drive mechanism are provided independently from each other via a partition wall that is inserted through the first valve shaft in an airtight state. Three pistons, one piston, are arranged in the piston and the lower cylinder, and are slidable with respect to both pistons and the piston rod in the upper cylinder. In addition to complicating manufacturing and making it difficult to make the structure compact, the piston on the upper cylinder is set in a free state, which may cause a malfunction due to being caught when the valve is fully opened. There was a problem.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a double seal valve that enables a compact structure of a valve opening / closing drive mechanism and that can be used safely without causing a malfunction.
[0005]
[Means for Solving the Problems]
The double seal valve according to claim 1 for solving the above problem is provided with a valve seat 6 in the communication passage 3 formed between the upper flow path 1 and the lower flow path 2, and the inner periphery of the valve seat 6. The first valve body 7 that engages with the first valve shaft 8 is slidable on the first valve shaft 8 and the second valve body 9 that press-engages with the upper side of the valve seat 6 is slidable on the first valve shaft 8 and The first valve shaft 8 is connected to the valve opening / closing drive mechanism 28 and is connected to the valve opening / closing drive mechanism 28 so that the valve opening / closing drive mechanism 28 is opened when the valve is opened. This is a double seal valve in which the second valve body 9 follows and moves as the first valve shaft 8 is moved upward, and the valve opening / closing drive mechanism 28 fixes the first valve shaft 8 to the piston rod as a piston rod. The piston 29 is an air cylinder that is inserted into the fixed cylinder 30, and a spring receiver 31 is disposed on the upper portion of the fixed cylinder 30. Between the piston 29 and the piston 29, a second spring 32 having a spring force larger than that of the first spring 11 interposed between the piston 29 and the second valve shaft 10 is fixed to the piston rod, and A spring limit stopper 33 that is connected to the spring receiver 31 so as to expand and contract and limits the extension of the second spring 32 to a certain range is interposed. Air supply / discharge ports 34 and 35 for supplying and discharging air are provided, air is supplied to the upper chamber 30a, and the piston 29 is pushed downward by the pressure increase in the upper chamber 30a, whereby the second spring 32 and the spring receiver 31 are supplied. It is characterized by the fact that it is lowered together with it.
[0006]
In the double seal valve according to claim 1, a second valve body opening / closing drive mechanism 36 comprising an air cylinder is provided below the valve opening / closing drive mechanism 28, and the second valve body opening / closing drive is provided. The mechanism 36 includes a second cylinder 37 formed in communication with the lower portion of the fixed cylinder 30, and a second cylinder that is fitted in the cylinder 37 and fitted on the second valve shaft 10 and moves up and down by a predetermined stroke S1. A piston 38; a third spring 39 for urging the second piston 38 to the lower limit position; and an air supply / discharge port 40 for supplying and discharging air to and from the lower chamber 37a of the second cylinder 37. With the upward movement of the second piston 38 due to the supply of air to 37a, the second valve shaft 10 moves upward against the urging force of the first spring 11 and opens the second valve body 9. It is characterized by being.
[0007]
According to a third aspect of the present invention, the double seal valve according to the second aspect is closed by the inner spring side upper end 38b of the second piston 38 biased to the lower limit position by the third spring 39 and the first spring 11. An axial play S2 shorter than the stroke S1 of the second piston 38 is provided between the stopper 43 provided at a required position of the second valve shaft 10 biased to the valve position, and the stroke of the second valve shaft 10 is increased. S1-S2 is used.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a vertical sectional view of a lower half obtained by dividing the entire double seal valve according to the present invention by aa line, and FIG. 2 shows the upper half. In these drawings, 1 is an upper flow path, 2 is a lower flow path, and these flow paths 1 and 2 are formed in parallel or intersecting directions. In addition, an upper opening 4 and a lower opening 5 are formed at portions that are coaxially opposed to the communication path 3 in both flow paths 1 and 2, and a valve seat 6 is mounted on the communication path 3. . For example, a drinking liquid or a cleaning liquid is circulated through the upper flow path 1 and the lower flow path 2, respectively.
[0009]
Reference numeral 7 denotes a first valve body that engages with the inner peripheral side of the valve seat 6, and an intermediate shaft portion 8 b of the first valve shaft 8 that is inserted from the upper opening portion 4 through the communication passage 3 to the lower opening portion 5 side. Are integrally formed at the lower end of the. A hollow lower shaft portion 8c is coaxially formed integrally with the lower portion of the first valve body 7, and an upper shaft portion 8a is normally coaxially connected to the upper portion of the intermediate shaft portion 8b by screw coupling. (In FIGS. 1 and 2, the intermediate shaft portion 8b and the upper shaft portion 8a are illustrated as being integrally formed). The first valve shaft 8 is formed by the upper shaft portion 8a, the intermediate shaft portion 8b, and the lower shaft portion 8c.
[0010]
Reference numeral 9 denotes a second valve body which is located on the upper side of the first valve body 7 and is pressed and engaged with the upper side of the valve seat 6 from above, and extends from the upper shaft portion 8a of the first valve shaft 8 to the intermediate shaft portion 8b. The second valve shaft 10 is integrally formed at the lower end portion of the second valve shaft 10 which is fitted, and the second valve shaft 10 is always urged downward by a first spring 11 made of a coil spring, as will be described later. The second valve body 9 is pressed against the upper side of the valve seat 6. The second valve shaft 10 includes an upper shaft portion 10a and a lower shaft portion 10b screwed to the upper shaft portion 10a. A second valve body 9 is formed at the lower end portion of the lower shaft portion 10b.
[0011]
As will be apparent with reference to FIG. 3 and subsequent drawings, the first valve body 7 has a main annular packing 12 slidably in close contact with the inner peripheral seat surface 6a of the valve seat 6 for fitting for packing. The secondary annular packing 13 that is in close contact with the upper seat surface 6b of the valve seat 6 from above is fitted into the packing mounting fitting groove 9a and attached to the second valve body 9. It has been. The upper opening 4 of the upper flow path 1 is provided with an annular member 14 that slidably supports the lower shaft portion 10b of the second valve shaft 10 protruding upward from the upper opening 4. Includes a base portion 15a of the yoke 15 and a packing 16 in close contact with the lower shaft portion 10b at the lower end portion thereof. In addition, the lower opening 5 of the lower flow path 2 is provided with an annular member 17 that slidably supports the lower shaft portion 8c of the first valve shaft 8 that protrudes downward from the lower opening 5. The member 17 includes a large-diameter base portion 18a of the sleeve 18 and a packing 19 that is in close contact with the lower shaft portion 8c at the upper end portion thereof.
[0012]
As shown in FIG. 1, a cleaning liquid supply port 20 is provided in the lower shaft portion 10 b of the second valve shaft 10, and this cleaning liquid supply port 20 is connected to the intermediate shaft portion of the first valve shaft 8 via a communication hole 21. The internal passage 22 communicates with a plurality of cleaning liquid ejection holes 23 provided radially at the lower end of the intermediate shaft portion 8b. When the cleaning liquid is supplied from the cleaning liquid supply port 20, the cleaning liquid enters the internal passage 22 of the intermediate shaft portion 8 b through the communication hole 21, and the first valve body 7 and the second valve 2 from the cleaning liquid ejection holes 23 at the lower end. After ejecting into the annular chamber 24 formed between the valve body 9 and the valve seat 6 to clean the inside of the annular chamber 23, the discharge passage inside the lower shaft portion 8 c passes through the plurality of through holes 25. 26 is discharged to the outside. A base 27 for connecting a cleaning liquid hose is attached to the cleaning liquid supply port 20 through a window 15 a of the yoke 15.
[0013]
Referring to FIG. 2, reference numeral 28 denotes a first valve opening / closing drive mechanism that controls opening and closing of the first valve body 7 and the second valve body 9. The valve opening / closing drive mechanism 28 includes a first valve opening / closing drive mechanism 28. The upper shaft portion 8a of the shaft 8 is a piston rod, and is composed of an air cylinder in which a piston 29 fixed to the piston rod is fitted in a fixed cylinder 30, and a spring receiver 31 is disposed in the upper portion of the fixed cylinder 30. Between the receiver 31 and the piston 29, a second spring 32 comprising a coil spring having a spring force larger than that of the first spring 11 interposed between the piston 29 and the second valve shaft 10, and the piston rod A spring limit stopper 33 which is fixed to the spring 8a and is connected to the spring receiver 31 so as to extend and contract to limit the extension of the second spring 32 to a certain range is interposed. Its upper and lower chambers 30a, the air supply and discharge ports 34, 35 for performing air supply and discharge to 30b are provided at a.
[0014]
The spring receiver 31 includes a ring-shaped spring receiver body 31o that receives one end of the second spring 32, and a cylindrical member 31a that is integrally formed concentrically therewith, and the spring limit stopper 33 is a piston rod ( The first valve shaft 8 is composed of a cylindrical member 33a that is externally fitted to the upper shaft portion 8a) and fixed in place and is slidably fitted to the cylindrical member 31a of the spring receiver 31. As shown in FIG. 2, the end portions of the cylindrical members 31a and 33a are engaged with each other by the urging force of the second spring 32, so that the spring receiver 31 and the stopper 33 are connected in a state where they extend to the maximum. As a result, the second spring 32 is restricted from extending further.
[0015]
Therefore, according to the first valve opening / closing drive mechanism 28, when no pressure air is supplied to any of the upper and lower chambers 30a, 30b across the piston 29 of the fixed cylinder 30, as shown in FIG. The first valve shaft 8 is biased upward and the second valve shaft 10 is biased downward by the biasing force of the first spring 11 interposed between the piston 29 and the upper shaft portion 10a of the second valve shaft 10. Then, the first valve body 7 is closely engaged with the inner peripheral seat surface 6 a of the valve seat 6 via the main annular packing 12, and the second valve body 9 is connected to the valve seat 6 via the auxiliary annular packing 13. The valve is fully engaged with the upper side seating surface 6b, and the valve is fully closed as shown in FIG.
[0016]
When pressure air is supplied from the air supply / discharge port 35 to the lower chamber 30b of the fixed cylinder 30, the piston 29 rises against the urging force of the second spring 32, and accordingly the cylindrical shape of the stopper 33 is increased. The member 33a contracts with respect to the cylindrical member 31a of the spring receiver 31, and the first valve shaft 8 starts to move upward. On the way, the upper end of the first valve body 7 is moved to the second valve as shown in FIG. In contact with the lower part of the inner peripheral side of the body 9, the first valve body 7 pushes up the second valve body 9 and rises together while the both valve bodies 7 and 9 are separated upward from the valve seat 6. However, when the stroke setting ring R fitted to the upper end side of the piston rod 8a contacts the upper wall portion 30c of the fixed cylinder 30, the piston 29 reaches the upper movement limit position, and the first valve body 7 and the first The two-valve element 9 is in a fully opened state as shown in FIG.
[0017]
In addition, by discharging the pressure air in the lower chamber 30b of the fixed cylinder 30 in the fully opened state, the piston 29 is moved to the second spring 32 while the spring receiver 31 is pressed against the upper wall portion 30c of the fixed cylinder 30. The first valve shaft 8 and the second valve shaft 10 move downward due to the urging force, and the first valve body 7 and the second valve body 9 return to the valve fully closed state as shown in FIG. . The stroke Sa of the piston 29 in the valve fully closed state (see FIG. 3) and the valve fully opened state (see FIG. 5) is set by the stroke setting ring R that contacts the upper wall portion 30c of the fixed cylinder 30.
[0018]
1 and FIG. 2, when the pressure air is supplied from the air supply / discharge port 34 to the upper chamber 30a of the fixed cylinder 30, the second spring 32 is extended by the spring limit stopper 33. Since the pressure is limited, the piston 29 is pushed downward by the pressure increase in the upper chamber 30a and is lowered together with the second spring 32 and the spring receiver 31, and accordingly, the first valve shaft 8 is moved to the first spring 11. The main annular packing 12 of the first valve body 7 slides downward on the inner peripheral side seating surface 6a of the valve seat 6 and moves away from the first seat as shown in FIG. Only the valve body 7 is slightly opened and the valve part is opened. In this way, by supplying the pressure air to the upper chamber 30a of the fixed cylinder 30, the first valve shaft 8 can be moved down alone, and only the first valve body 7 can be in a partially open state. In this case, the piston 29 starts to descend from the position shown in FIG. 2 and stops after coming into contact with the upper end of the second cylinder 37 described later. Therefore, the stroke is Sb shown in the figure, and the first valve shaft 8 moves up and down independently of the second valve shaft 10 by this stroke Sb.
[0019]
Below the first valve opening / closing drive mechanism 28, a second valve body opening / closing drive mechanism 36, which is also formed of an air cylinder, is provided. The second valve body opening / closing drive mechanism 36 is fitted into the second cylinder 37 formed in communication with the second cylinder 37 below the fixed cylinder 30 of the first valve opening / closing drive mechanism 28. In addition, a third piston comprising a second piston 38 that moves up and down a predetermined stroke in a state of being fitted on the upper shaft portion 10a of the second valve shaft 10, and a coil spring that biases the second piston 38 to the lower movement limit position. 39 and an air supply / discharge port 40 for supplying and discharging air to and from the lower chamber 30a of the second piston 38. As can be seen from FIG. 2, the second cylinder 37 is connected to the lower end portion of the fixed cylinder 30 of the first valve opening / closing drive mechanism 28 by screw connection, and the upper chamber 37 b of the second cylinder 37 and the first cylinder 37 are connected to each other. The one-valve opening / closing drive mechanism 28 is formed so as to communicate with the lower chamber 30b of the fixed cylinder 30.
[0020]
In FIG. 2, 41 is a stopper that regulates the lower limit position of the second piston 38, and is formed on the lower wall side of the second cylinder 37, and 42 is a stopper that regulates the upper limit position of the second piston 38. Thus, it is formed on the upper wall portion side of the second cylinder 37. Thus, the second piston 38 corresponds to the distance between the upper end 38a on the outer peripheral side of the piston 38 and the upper movement limit position restriction stopper 42 between the lower movement limit position restriction stopper 41 and the upper movement limit position restriction stopper 42. The stroke S <b> 1 is moved up and down, but the upper end 38 b on the inner peripheral side of the second piston 38 biased to the lower limit position by the third spring 39 and the valve closing position biased by the first spring 11. Since the axial play S2 shorter than the stroke S1 is provided between the stopper 43 projecting from the upper shaft portion 10a of the two valve shaft 10, the second piston 38 is moved from the lower movement limit position. By raising the stroke S1 to the upper movement limit position, the second valve shaft 10 actually moves up by the difference (S1-S2) between the stroke S1 of the second piston 38 and the axial play S2. Especially That. Thus, the inner peripheral side upper end 38b of the second piston 38 urged to the lower limit position by the third spring 39, and the second valve shaft 10 side urged to the valve closing position by the second spring 32. By providing an axial play S2 shorter than the stroke S1 of the second piston 38 between the stopper 43 of the second piston 38, the urging force of the second spring 32 is effectively applied to the second valve shaft 10, and the second The valve body 9 can be reliably pressed and engaged with the upper side seating surface 6 b of the valve seat 6.
[0021]
In the second valve opening / closing drive mechanism 36, the lower chamber 37a of the second cylinder 37 is provided from the air supply / discharge port 40 from the state where the second piston 38 is held at the lower limit position as shown in FIG. When the pressurized air is supplied to the second valve shaft 10, the second piston 38 starts to move upward, but until the inner peripheral side upper end 38 b of the piston 38 hits the stopper 42 of the second valve shaft 10, The second valve body 9 remains held at the lowered position. Thus, the second valve shaft 10 is pushed up along with the upward movement of the second piston 38 after the inner peripheral upper end 38b of the second piston 38 hits the stopper 42, and the outer peripheral upper end of the piston 38 is pushed up. The valve 38a moves upward until it hits the upper movement limit position restricting stopper 42, so that only the second valve body 9 is slightly opened as shown in FIG. Further, by removing the pressure air from the lower chamber 37a, the second piston 38 is pushed down by the third spring 39, the second valve shaft 10 is moved down by the second spring 32, and the second valve body 9 is closed. It becomes a valve state.
[0022]
When the double seal valve having the above-described configuration is used, when the pressure air is not supplied to the lower chamber 30b of the fixed cylinder 30 in the first valve opening / closing drive mechanism 28, it is shown in FIGS. As described above, the first valve body 7 is closely engaged with the inner peripheral side seat surface 6 a of the valve seat 6 via the main annular packing 12, and the second valve body 9 is pushed by the second valve shaft 10 pushed down by the first spring 11. Is pressed and engaged with the upper seat surface 6b of the valve seat 6 via the auxiliary annular packing 13, so that the first valve body 7 and the second valve body 9 are both closed, and the upper flow The communication path 3 that connects the path 1 and the lower flow path 2 is closed in a double-sealed state by the first valve body 7 on the lower flow path 2 side and the second valve body 9 on the upper flow path 1 side. Mixing of the liquid flowing through the upper flow path 1 and the liquid flowing through the lower flow path 2 is prevented.
[0023]
When pressurized air is supplied to the lower chamber 30b of the fixed cylinder 30, the first valve body 7 pushes up the second valve body 9 as the first valve shaft 8 moves upward as shown in FIG. While being lifted up together, both valve bodies 7 and 9 are sufficiently separated upward from the valve seat 6 so that the valve is fully opened as shown in FIG. 5. As a result, the communication passage 3 is opened and the communication passage 3 is opened. The upper flow path 1 and the lower flow path 2 can be communicated.
[0024]
Also, when using a liquid that is difficult to clean, such as a highly viscous liquid, close one of the first valve body 7 and the second valve body 9 and slightly open the other, and the opened packing portion The washing liquid is discharged while washing with the washing liquid. For example, when high-viscosity drinking water is circulated in the upper flow path 1 and cleaning liquid is circulated in the lower flow path 2, if pressure air is supplied to the upper chamber 30a of the fixed cylinder 30, the pressure in the upper chamber 30a increases. The piston 29 is lowered together with the second spring 32 whose extension is restricted, and the first valve shaft 8 is moved downward accordingly, and the main annular packing 12 of the first valve body 7 is moved to the inner peripheral side seating surface of the valve seat 6. 6a is slid downward and separated, and only the first valve body 7 is slightly opened as shown in FIG. Accordingly, the cleaning liquid from the lower flow path 2 passes through the gap between the first valve body 7 and the valve seat 6 as shown by the arrow in FIG. 6, and the first valve body 7 and the second valve body 9. Is introduced into an annular chamber 24 formed between the valve seat 6 and the main annular packing 12 portion of the first valve body 7 and the interior of the annular chamber 2 during that time, and then the lower portion of the first valve shaft 8. It is discharged to the outside through the discharge path 26 inside the shaft portion 8c.
[0025]
In addition, when highly viscous drinking water is circulated through the lower flow path 2 and cleaning liquid is circulated through the upper flow path 1, pressure air is supplied to the lower chamber 37 a of the second cylinder 37 in the second valve opening / closing drive mechanism 36. When supplied, the second valve shaft 10 is pushed up by the piston 38 while the second piston 38 moves upward, and the second piston 38 moves upward by a predetermined stroke S1, so that the second valve shaft 10 moves in the axial direction. Only the stroke (S1-S2) obtained by subtracting the play S2 is moved up, and only the second valve body 9 is slightly opened as shown in FIG. Accordingly, the cleaning liquid from the upper flow path 1 passes through the gap between the second valve body 9 and the upper seat surface 6b of the valve seat 6 as indicated by the arrow in FIG. And the inside of the annular chamber 24 formed between the second valve body 9 and the valve seat 6 to wash the sub annular packing 13 portion of the first valve body 7 and the interior of the annular chamber 2, The valve shaft 8 is discharged to the outside through the discharge passage 26 inside the lower shaft portion 8c.
[0026]
[Action and effect of the invention]
The double seal valve according to claim 1 is characterized in that the valve opening / closing drive mechanism that controls opening and closing of the first valve body and the second valve body includes a single piston fixed to the first valve shaft as a piston rod in a fixed cylinder. The air cylinder is inserted into the fixed cylinder, and a spring receiver is disposed in the upper part of the fixed cylinder. The first is interposed between the piston and the second valve shaft between the spring receiver and the piston. A second spring having a spring force larger than that of the spring and a spring limit stopper fixed to the piston rod and connected to the spring receiver so as to be stretchable and restricting the extension of the second spring to a certain range are interposed. When the pressure air is not supplied to both the upper and lower chambers of the fixed cylinder, the first valve shaft is biased upward and the second valve shaft is biased downward by the first spring, so that the first valve body Engages with the inner periphery of the valve seat and The valve body is engaged with the upper side of the valve seat, a valve full-closed state. When pressure air is supplied to the lower chamber of the fixed cylinder, the piston rises against the biasing force of the second spring, and the spring limit stopper contracts with respect to the spring receiver along with this, and the first valve shaft Starts to move upward, and while the first valve body pushes up the second valve body and rises together, both valve bodies are separated upward from the valve seat and the valve is fully opened. When the pressure air in the lower chamber is released, the first valve shaft is moved down to the original position by the urging force of the second spring, and the first valve body and the second valve body are both closed. .
[0027]
Further, when the pressure air is supplied to the upper chamber of the fixed cylinder in the fully closed state of the valve, the extension of the second spring is restricted by the spring restriction stopper, so that the piston is pushed downward and the second spring and the spring are pushed. has a configuration which descends receiving and integrally, the first valve shaft along with it against the urging force of the first spring moves downward, the valve partially open state in which only the first valve body is opened. Thus, by supplying the pressure air to the upper chamber of the fixed cylinder, the first valve body is opened and the second valve body is closed.
[0028]
Therefore, according to the present invention, the valve open / close drive mechanism can supply or discharge the pressure air to the lower chamber of the fixed cylinder, so that the valve can be fully opened or fully closed. By supplying pressure air to the chamber, the first valve body can be opened and the second valve body can be closed. Since this valve opening / closing drive mechanism is provided with only one piston in the fixed cylinder and fixed to the piston rod, only one airtight seal portion is required, and the structure is simplified and manufactured. Simplification can be achieved, and the piston does not malfunction, so that the valve does not malfunction.
[0029]
In the invention according to claim 2, by providing the second valve opening / closing drive mechanism below the first valve opening / closing drive mechanism, in addition to the operation of the invention of claim 1 described above, the following Works. That is, when the pressure air is supplied to the lower chamber of the second cylinder from the state where the second piston is held at the lower limit position, the second valve shaft is pushed up with the upward movement of the second piston, When only the second valve body is opened, the valve is partially opened, and by releasing the pressure air in the lower chamber, the second piston is pushed down by the third spring, and the second valve shaft is moved down by the second spring, The second valve body is closed.
[0030]
Thus, according to the present invention, the second cylinder in the second valve opening / closing drive mechanism has a lower part of the fixed cylinder of the first valve opening / closing drive mechanism without a partition as in the conventional device described at the beginning. Since it is formed in communication with the fixed cylinder, it is possible to simplify the structure and make it compact, thus facilitating the manufacture.
[0031]
According to the third aspect of the present invention, the upper end of the second piston is biased to the lower limit position by the third spring, and the second valve shaft is biased to the closed position by the second spring. By providing an axial play shorter than the stroke S1 of the second piston between the stopper and the stopper, the urging force of the second spring is effectively applied to the second valve shaft, and the second valve body is attached to the valve seat. The upper side can be surely pressed and engaged.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a lower half of a double seal valve according to the present invention, and an aa line is a dividing line with an upper half.
FIG. 2 is a longitudinal sectional view showing an upper half of the double seal valve.
FIG. 3 is a longitudinal sectional view showing a center portion of a double seal valve in a valve fully closed state.
FIG. 4 is a longitudinal sectional view of a central portion of a double seal valve showing a state in which the valve is in a fully open state to a valve open state.
FIG. 5 is a longitudinal sectional view showing a center portion of a double seal valve in a fully opened state of the valve.
FIG. 6 is a longitudinal sectional view showing a valve partial open state in which the first valve body is slightly opened.
FIG. 7 is a longitudinal sectional view showing a valve partial open state in which a second valve body is slightly opened.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper flow path 2 Lower flow path 3 Communication path 6 Valve seat 7 1st valve body 8 1st valve shaft 9 2nd valve body 10 2nd valve shaft 11 1st spring 28 1st valve opening / closing drive mechanism 29 Piston 30 fixation Cylinder 30a Upper chamber 30b Lower chamber 31 Spring receiver 32 Second spring 33 Spring limit stopper 34 Air supply / discharge port 35 Air supply / discharge port 36 Second valve opening / closing drive mechanism 37 Second cylinder 38 Second piston 39 Third spring 40 Air Supply / exhaust port

Claims

A valve seat is provided in the communication path formed between the upper flow path and the lower flow path, and the first valve body engaged with the inner peripheral side of the valve seat is pushed to the first valve shaft and to the upper side of the valve seat. The second valve body that is in contact with the first valve shaft is provided on the second valve shaft that is slidable on the first valve shaft and is always urged downward by the first spring. A double-seal valve that is linked to a valve opening / closing drive mechanism and the second valve body follows in accordance with the upward movement of the first valve shaft by the operation of the valve opening / closing drive mechanism when the valve is opened. The first valve shaft is a piston rod, and a piston fixed to the air cylinder is inserted into the fixed cylinder. A spring receiver is arranged in the upper part of the fixed cylinder. Between the spring receiver and the piston, A second spring having a spring force larger than that of the first spring interposed between the piston and the second valve shaft; And a spring limit stopper that restricts the extension of the second spring to a certain range and is connected to the spring receiver in a telescopic manner, and the fixed cylinder supplies air to the upper and lower chambers sandwiching the piston. An air supply / exhaust port for exhausting is provided , air is supplied to the upper chamber, and the piston is pushed downward by the pressure increase in the upper chamber so that it is lowered together with the second spring and spring receiver. Double seal valve characterized by

A second valve body opening / closing drive mechanism including an air cylinder is provided below the valve opening / closing drive mechanism, and the second valve body opening / closing drive mechanism includes a second cylinder formed in communication with a lower portion of the fixed cylinder; A second piston that is fitted in the cylinder and fitted on the second valve shaft and moves up and down by a predetermined stroke S1, a third spring that urges the second piston to the lower limit position, and a second cylinder An air supply / exhaust port for supplying / exhausting air to / from the lower chamber, and the second valve shaft resists the urging force of the first spring as the second piston moves upward by supplying air to the lower chamber. The double seal valve according to claim 1, wherein the double seal valve is moved upward to open the second valve body.

Between the upper end on the inner peripheral side of the second piston biased to the lower limit position by the third spring and the stopper provided at the required position of the second valve shaft biased to the valve closing position by the first spring The double seal valve according to claim 2, wherein an axial play S2 shorter than the stroke S1 of the second piston is provided so that the stroke of the second valve shaft is S1-S2.