【０００１】
【発明の属する技術分野】
本発明は、表面張力が、２０℃において、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力を有する液体の漏液を、小量でも高速に検知することの可能な漏液センサの改良に関する。
【０００２】
【従来の技術】
従来工場等の設備では配管により液体を供給している。しかし、配管には多くの個所に接続用の継手が設けられているため継手から液体が漏液する場合が多い。そこで、液体の種類によっては漏液の監視を人間が常時行なわなければならなかった。かかる従来の漏液監視方法としては導電方式や液量方式が知られている。又、特公平４−７０５７２号公報には漏液を吸収すると透明になるフイルタに光源より光を照射しておき、漏液があった時に上記フイルタからの透過光又は反射光の変化量を検知することにより漏液を確実に検知できるようにした漏液センサ技術が記載されている。
図１（Ａ）は、かかる従来の反射光検知方式の漏液センサ２０の原理を示す図であり、床面１に、薄紙８及びケース１２のホルダ（通常、約０．９ｍｍ〜０．１ｍｍ前後の板厚の金属板）４が、その上底面４ａを艶消し黒色で鍍金され反射光吸収板を兼ねてネジ等の止め具により固定され、その上に白色の薄紙（紙、布、ガラス、又は、合成樹脂部材等でも良く、漏液を吸引しない場合は白色で反射し、漏液を吸引すると透明／光透過材となるもの）８が載置されている。又、ホルダ４には、底部１２ｄが透明又は半透明な合成樹脂材又はガラス等のセラミックス材で構成されたケース１２が、挿入／装着され、ケース１２の内部には光源手段（投光部）１４、受光手段（光電変換部）１６及びコンパレータ等を含む検知手段（制御部、演算手段）１８が一体化して収容され、ケーブル２６を介して外部と接続されるようになっている。
尚、ケース１２は、外来ノイズ光を遮断すると共に、防塵、防水用のフタを兼ねているが、漏液２が薄紙８の中央の反射領域８ｂに浸透し易くし、かつ、漏液の検出時間を短縮するため、ケース底部１２ｄの底面１２ａと薄紙８との間には微少な空隙部（薄紙を使用しないタイプのセンサでは気体層を形成する）１０が設けられており、ホルダ底面４ａとケース底面１２ａとの平行間隙ｄは、漏液を吸引する漏液浸透層を形成している。この空隙ｄは、ほこり、ちり等の汚れを避けると共に、外部のノイズ光を検知せず、安定的に薄紙８からの反射光を検出するため、数ｍｍ以内が望ましく、又、反射板４ａとケース１２とを着脱可能な構造のフイルタとした方が、薄紙８の交換や設置作業等が容易なことが分った。更に又、漏液の発生個所が一般的には特定できないことから、どの方向から浸透して来る漏液に対しても素早く応答するため、薄紙の形状は一般的には円形が好ましいことも分った。
このような構成において、通常、ＬＥＤや赤外線発光素子、半導体レーザ、投光用光ファイバ等の光源手段１４から漏液検知光２２が照射され、薄紙８からの白色の反射光２４が、受光手段１６により常時検出されている。しかして、床面１に漏液２が生じた場合、接触部９から漏液２が順次薄紙８の反射領域８ｂに浸透していき、薄紙８の接触部９は漏液の浸透により白色から透明色に変化する。しかるに、薄紙８の下側の反射板４ａは黒色であるので、薄紙８の色は接触部９では白色から黒色に変化し、受光手段（受光用光ファイバを含む）１６への反射光２４は反射板４ａに吸収されて大幅に減少し、検知手段（制御手段）１８によりこの反射光量の変化を検出して漏液検知が行われる。
かかる薄紙を利用した漏液センサは、構造が簡単で、動作も確実であり、止め具等で床面に固定されているので、センサが転倒する事故もなく、粘度の高い液体でも比較的短時間で検知できる利点があるが、ホルダの床面設置作業や薄紙の交換作業をできるだけ省略したい利用者からは、薄紙を使用せず、床面設置作業の不要な漏液センサが要望されていた。
【０００３】
【発明が解決しようとする課題】
かかる薄紙８の不用な漏液センサとしては、上述のケース底部１２ｄの底面１２ａに全反射光を生ずるように、光源手段から投射光を所定の入射角度で照射し、その反射光量の大小により漏液の有無を判定するものが種々考案されているが、ケース底部と床面とを密着させると、粘度の高い液体はケース底部の中央部には非常に浸透しにくくなるので、
（Ａ）一般に、薄紙８の不用な漏液センサであって、ケース底部１２ｄの底面１２ａに漏液検知用全反射光を生ずるように構成した漏液センサでは、薄紙を使用する漏液センサよりも遥かに大きい、最小でもｄ＝２〜４ｍｍの空隙部を、床面とケース底面との間、又は、ホルダ上面４ａとケース底部との間に設けた構造が採用されており、大量に漏液が流出して、漏液の液位（液面）が漸次上昇し、漏液発生時から非常に長時間経過した後に、ケース底部が漏液と接触した後でないと、漏液が全く検知できないという問題点があった。従って、小量（例えば、５ｃｃ、好ましくは、２ｃｃ）の漏液では、漏液が、何時間経っても全く検知できないという問題点があった。
（Ｂ）又、ケース底部が、ホルダ／キャップなしで直接床面に対向して露出している構造のセンサで、かつ、ケース本体の外部に漏液検知用反射境界面を設けた構造のセンサでは、床面の塗装色の影響を受けやすく、漏液が浸透して来た段階で不必要な床面からの反射光を大量に受光してしまい、誤作動する等、反射光量の大小だけでは漏液の有無判定が安定しないという問題点もあった。
（Ｃ）更に、洗浄剤／溶剤として、例えば、２０℃において、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力を有する液体の漏液を検知する場合であって、特に、塩素や臭素を含まない低分子のクロロフロロカーボン（ＣＦＣｓ）やハロン等の、表面張力が、２０℃において、３０ｄｙｎｅｓ／ｃｍ以下である低表面張力を有する液体の漏液２ａを検知する場合には、漏液２ａが、非常に薄く、その厚さｄ１が、図１（Ｃ）に示すように、０．５ｍｍ以下の薄膜状に均一に素早く拡散すると共に、０．１ｍｍ以下の非常に間隔の狭い空隙部にも、容易に浸透してしまうので、図１（Ｄ）に示すように、ケースホルダ４と床面１との隙間ｄ２（＜ｄ１）に、先ず浸透し、ホルダ上面まで漏液２ａが拡散するのに長時間を要し、結果として、小量の漏液検知が全くできなかったり、漏液の検知が遅れるといった問題点が発生した。
（Ｄ）一方、薄紙８を使用する漏液センサの場合には、ケース底部１２ｄの底面１２ａとホルダ４の上面４ａとの間隙ｄを１ｍｍ以内とした空隙部／漏液浸透層形成しているが、床面１からの反射光の影響を低減／無くすため、漏液検知領域に対応した床面１の上面には、必ず、ホルダ底面４ａが床面１を覆うように底面４ａが加工／形成され、その上に薄紙８が載置され、漏液検知領域に対応した床面１に薄紙８が、直接、接触した状態で漏液センサが構成されることは、無かった（図７（Ｃ））。
従って、上記ＣＦＣｓやハロン等の、２０℃において、３０ｄｙｎｅｓ／ｃｍ以下である低表面張力を有する揮発性の高い液体の漏液２ａを従来の薄紙８で検知せしめる場合には、先ず、漏液２ａがホルダ上面４ａの水位まで上昇するのに必要な時間が必要であり、更に、漏液２ａがホルダ上面４ａを乗り越えるのに十分な水位まで上昇するのに必要な時間経過した後、ホルダ上面４ａ上で、上記漏液２ａが、従来の薄紙８を簡単に鉛直方向に透過して急速に蒸発してしまうため、水平方向に対しては、非常に緩やかに浸透し拡散するプロセスが進行し、薄紙８が漏液浸透層として透明に変化し伝搬していく速度は極めて遅く、長時間が必要となり、本発明者の実験によれば、水等の表面張力の大きい液体の薄紙浸透速度と比較すると、約１０〜１００倍以上の長時間を要し、結果として、低表面張力を有する漏液２ａの検知時間が漏液発生時点から非常に遅れてしまうといった問題点や、小量の漏液では、漏液２ａがホルダ上面４ａを乗り越えるのに十分な水位まで漏液量が確保できず、漏液２ａが全くが検知できないといった問題点が発生した。尚、漏液２が水の場合、床面の性状、材質や流出した漏液の量に応じて変化するが、本発明者の実験によると、通常、図１（Ｅ）に示すように、漏液面の高さｄ３は、約２ｍｍ〜７ｍｍの範囲で変化することが分かった。
又、従来の光学式漏液センサには、当初予期できなかった次のような問題点も発生した。
（Ｅ）床面１にホルダ底面４ａが水平であり、ケース底面１２ａもほぼ水平な状態で設置した状態で、高圧配管や大口径配管等が破損し、一度に大量の漏液が発生／流出した場合、ケース１２の下部は全周がほぼ同時に漏液中に水没してしまう。かかる状態で漏液２が順次薄紙８の外縁部からその内側に向って浸透し始めると、ホルダ底面４ａとケース底面１２ａとの空隙部１０にあった気体は、一部が泡となってケース１２の外側に排出されるが、空隙部１０の中央近傍にあった気体は、その周囲を漏液で塞がれた状態となり、図１（Ｂ）に示すように、気泡が中央部であり、かつ、漏液検知光の反射領域でもある８ｂに停留し、何時間たっても反射領域８ｂに漏液が浸透せず、従って、薄紙８が透明にならず、大量の漏液を検出できない現象が発生した。
よって本発明は上述のような事情に鑑みて成されたものであり、本発明の目的は、２０℃において、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力を有する液体の小量の漏液でも、高速に検知することの可能な漏液センサを提供することにある。又、漏液センサのケース設置作業中、ケースが単独で浮き上がったり、傾斜したり、転倒している事故を速やかに検知したり、ケース設置作業後、ケースがホルダから浮き上がったり、転倒した事故を、速やかに検知して外部に警告することの可能な、設置異常検知手段付きの簡単／確実な構造の漏液センサを提供することにある。
更に、本発明の目的は、２０℃において、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力を有する液体の漏液と、２０℃において、６０ｄｙｎｅｓ／ｃｍ以上である表面張力を有する液体の漏液とを、どちらも、小量の漏液であっても高速に検知することの可能な漏液センサを提供することにもある。
【０００４】
【課題を解決するための手段】
本発明は、漏液と接触し得る漏液検知用反射境界面と、光源手段、受光手段及びこれらに結合された制御手段とから成る漏液センサに関し、本発明の上記目的は、
表面張力が、２０℃において、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液を、所定の隙間及び所定の断面形状の毛管現象を発現しうる空隙部を利用して、重力に抗して、前記漏液検知用反射境界面まで床面から、小量でも、直接速やかに引き上げ導くための高速漏液引込手段を、少なくとも１つ具え、
前記光源手段の投射光を前記漏液検知用反射境界面に照射し、当該反射境界面からの反射光を前記受光手段で受光し、その出力を前記制御手段により演算処理して、前記低表面張力の漏液の有無を速やかに判定できるようにすることにより達成される。
【０００５】
【発明の実施の形態】
以下、図面に基づいて、本発明の好適な実施例について詳細に説明する。図１（Ａ）に対応させて示す図２乃至図５は、本発明の漏液センサ２０ａの一実施例を示すものであり、それぞれ同一の番号を付した装置は同一の機能を果たすと共に、表面張力が、２０℃において、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液を、所定の隙間及び所定の断面形状の毛管現象を発現しうる空隙部を利用して（例えば、隙間１ｍｍ以下の平行空隙部、及び／又は、最大隙間１ｍｍ以下で上方に向けて漸次狭くなる楔状空隙部）、重力に抗して、漏液検知用反射境界面の漏液検知位置まで床面から、小量の漏液でも、直接速やかに引き上げ導くための後述する高速漏液引込手段６を、少なくとも１つ、光源手段及び受光手段を底部が透明材又は半透明材で構成されたケースに収納し一体化したケース１２と、当該ケースを装着するケースホルダ５とで構成することにより設けたもので、
ＡＢＳ樹脂、ポリエチレン、ポリ塩化ビニル、ポリスチレン、ポリプロピレン、ポリビニルアルコール、メタクリル樹脂、石油樹脂、ポリアミド、ポリ塩化ビニリデン、ポリカーボネート、ポリアセタール、弗素樹脂、ポリイミド、ポリエーテルエーテルケトン、ポリフェニレンスルフィド、ポリベンズイミダゾール、ポリシクロオレフィン等の熱可塑性樹脂、又は、フェノール樹脂、尿素樹脂、不飽和ポリエステル、ポリウレタン、アルキド樹脂、メラミン樹脂、エポキシ樹脂等の熱硬化性樹脂、則ち、熱可塑性樹脂又は熱硬化性樹脂等の合成樹脂部材／プラスチック部材、又は、ポリアミノ酸、脂肪族ポリエステル、ポリーεーカプロラクトン、ポリビニルアルコール、キトサン、澱粉、セルロース等と汎用性ポリマーとの混合物等の生分解樹脂部材、又は、これらの組合せから成るグループから選択されたもの、
更に、ポリアミド、ポリカーボネート、ポリアセタール、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリフェニレンエーテル、ポリエーテルエーテルケトン、ポリフェニレンスルフィド、ポリアリレート、ポリスルホン、ポリエーテルスルホン、ポリケトンスルフィド、ポリエーテルイミド、ポリアミドイミド、ポリイミド、ポリ四弗化エチレン、芳香族ポリエステル、ポリアミノビスマレイミド、トリアジン樹脂等のエンジニアリングプラスチック部材、又は、ガラス、又は、セラミックスを少なくとも１つを含む透明材又は半透明材で構成されたケース１２の底部１２ｄに、図５に示すような凸形状で、その底面１２ｐが床面１に直接密着接触可能な漏液検知部を突設して設け、
この検知部には、床面１に対して約３５度〜５０度の所定の傾斜角度で平面状の漏液検知用全反射面１２ｍ及び１２ｎを設け、これらの平面状全反射面１２ｍ及び１２ｎは、コーナーキューブと同等の機能を果たすように、全反射面の延長が相互に所定の角度で交差するように形成し、少なくとも１つの光源手段、受光手段及びこれらに結合された制御手段を、上記各反射境界面のそれぞれに対し、同一の側に配設し、上記第１の全反射境界面に対しては光源手段から光を投射し、第１の全反射境界面からの反射光を第２の全反射境界面に投射し、第２の全反射境界面からの反射光を受光手段で受光し、その出力を前記制御手段により演算処理して漏液を検知するため、
先ず、漏液検知用の第１の光学系を形成する光源手段１４ａからの投射光２２ｕが、全反射面１２ｍに上方から下方に全反射面１２ｍで所定の臨界角以上で全反射するように、透明材又は半透明材１２ｄの屈折率に応じた所定の入射角で照射され、その反射光２２ｖが全反射面１２ｎに投射され、全反射面１２ｎからの全反射光２４ｕが、透明材又は半透明材１２ｄの屈折率に応じた所定の受光角度でＣＣＤやＭＯＳ型ホトダイオード等から成る光電変換素子の受光手段１６で受光され、かかる光学経路を伝搬した漏液検知光が電気信号に変換され、その出力が、例えば、図６に示すようなマルチプレクサ３１を介して、所定のサンプリング周期毎にＡ／Ｄ変換手段３２によりデジタル信号に変換され、マイクロプロセッサ（ＭＰＵ）３６を含み検知手段１８を兼ねた制御手段３０内の、バッファメモリ３４に順次書込まれ、デジタル処理されたり、受光手段１６のアナログ出力が、直接、図示しないアナログ比較器等から成るアナログ演算手段に入力され、アナログ回路から構成された検知手段１８を兼ねた制御手段３０内で、アナログ処理することも可能である。尚、上記光源手段１４ａ、受光手段１６、検知手段１８、及び、制御手段３０等は、遮光材を兼ねた回路基板７に、一体に形成し、固定するのが好ましい。
次に、ケース１２の床面１に対する平行度をチェックする設置異常検知手段７０として第２の光学系が、上記第１の光学系とは、独立して設けられ、この第２の光学系では、光源手段１４ｃからの投射光が薄紙８に向かって投射され、ホルダ５の中空部を有するリング状枠体５ａの内周部に、内側リング中心方向に向かって、突起部５ｈが枠体５ａと一体に形成され、この突起部５ｈの上面に、光の吸収材／透光材で形成された載置平面５ｊが形成され、かかる平面５ｊの上に薄紙８の一部分が載置され、第３の光学的（反射）反射面である薄紙８に対し、ケース底部１２ｄの臨界角未満の入射角で光２２ｚが照射され、その反射光２４ｚが受光手段１６ｃにより受光され、上述と同様にして電気信号に変換されて制御手段３０に入力されるようになっている。尚、光源手段１４ｃと受光手段１６ｃとの間に、光源手段１４ｃから受光手段１６ｃへ直接入射する投射光の遮光材１２ｑを充填／形成するのが好ましく、上記第１の光学系と第２の光学系とを光学的に分離するためにも、これらの間に、遮光材１２ｑを充填／形成するのが好ましい。
又、制御手段３０は、漏液の有無判定手段と、ケースの設置異常判定手段とを兼ねて動作せしめることが可能であり、又、ケース１２の床面１に対する平行度をチェックする設置異常検知手段７０は、上記例では、光学式設置異常検知手段であるが、この他に、磁石や静電容量の変化を利用した設置異常検知手段も利用可能である。
又、ケース底部１２ｄの内側には、金属箔等の遮光材を貼着することも可能であり、かかる遮光材は、ケース底部の光の照射面及び受光手段近傍の反射光受光面を除いた範囲に配設すると、漏液浸入時に床面が白色又は鏡面であっても不要な反射光を床面から遮断し、受光しない光学的効果がある。更に、制御手段３０で処理した漏液の検知出力は外部にケーブル２６を介して電気信号として出力され、更にケース１２の上面に設けられた表示手段２９にも、緑色／赤色切換点灯可能なＬＥＤ等により警告表示されるようになっている。尚、ホルダ５の外径がケース１２の外径の１．３倍以上の大きさのものを使用した方が、センサ２０ａの転倒防止の面から好ましく、ケーブル２６の腰が強い場合、ケース１２を単独で設置すると、ケース１２が容易に転倒しやすいので、通常は、ケース１２を挿入したホルダ５を床面１にネジ等の固定材によりしっかりと固定し、更に／又は、建物や机等の側壁や側面６１からケース１２を固定するためのアーム状の圧接手段６０をケース上蓋に延設し（図２（Ｃ））、その一端６２をネジ、釘等の固定材６４により建物６１側に固定すると共に、他端６６をケース上部に圧接し、ケース１２の転倒防止を図ってもよい。
又、ケース底部１２ｄと床面１との間隔ｄ４は、検知する液体の粘度／表面張力に対応して種々のものに変更できることが好ましいが、地震や重量物の移動等により、反射境界面１２ｍ，１２ｎと床面１との角度や間隔が変化すると、誤動作の原因となりやすいので、ホルダ５とケース１２とは、後述するようなワンタッチ着脱可能で、かつ、間隔ｄ４が外部の振動に対しても変化しない構造のものが好ましい。又、ホルダ５は遮光材で構成すると、ケース１２の周囲からノイズ光が侵入したり、床面からの不要な反射光の受光を防止する効果がある。又、ホルダ５を使用せず、ケース１２を単体で漏液センサ２０ａとして使用する場合は、上述の間隔ｄ４が外部の振動に対しても変化しないように、別途設置した圧接手段６０等により床面１に固定するのが好ましい。尚、上記光源手段１４ｃ、受光手段１６ｃ、及び、表示手段２９等も、遮光材を兼ねた回路基板７に、一体に形成し、固定するのが好ましい。
【０００６】
次に、漏液検知用投射光２２ｕの全反射面１２ｍへの照射位置は、床面１に近い下方の位置が好ましく、ケース１２の底部に設けられた凸形状の漏液検知部底面１２ｐ等は、図４（Ｃ）に示すような切断線条８ｄを所定箇所に形成した薄紙８の密着シート押さえとして利用可能である。又、光源手段１４ａと受光手段１６との間に、光源手段１４ａから受光手段１６へ直接入射する投射光の遮光材１２ｑを充填／形成するのが好ましい。
しかして、ケース１２全体は、本発明の主として中央中空部を有するリング状枠体５ａから成るホルダ５（図４（Ａ），（Ｂ））に挿入／装着により嵌合されて固定されるようになっており（図２）、枠体５ａの床面１に対向する底面５ｂ（図４（Ｂ））は、床面１から所定の間隔ｄ５（通常２ｍｍ〜５ｍｍの範囲の空隙部が形成できる間隔が好ましい）を保って略平行に形成され、ケース１２の底部１２ｄに、凸形状で底面１２ｐが薄紙８を挟持して床面１に直接密着接触する漏液検知部が突設して設けられているので（（図２（Ｂ），図５）、床面１に薄膜状に拡散する低表面張力の漏液２ａを、中央中空部に拡散した床面１から直接検出することが可能であり、一方、ホルダ５は、リング中心から外側方向の外周部に設けられた単一又は複数箇所の突起子５ｃに形成された貫通穴５ｄを利用して、床面１にクギ／ネジ等の固定材により固定してもよいし、突起子５ｃの扇状底面に接着剤を貼着し床面１に密着して接着固定してもよい（図４）。又、固定せず、単に床面１に移動自在に載置しておくだけでもよい。更に、建物や机等の側壁や側面６１からケース１２を固定するためのアーム状の圧接手段６０をケース上蓋に延設し、その一端６４を固定部材６２により建物６１側に固定すると共に、他端６６をケース上部に圧接し、ケース１２の転倒防止を図ってもよい（図２（Ｃ））。
更に、図２の例では、光源手段１４ａ，１４ｃ及び受光手段１６、１６ｃを、底部１２ｄが透明材又は半透明材で構成されたケース内部に収納し一体化したケース１２の底部と、ケース１２を装着するケースホルダ５とで高速漏液引込手段６を構成するようになっており、その構成（図５）は、例えば、枠体５ａの内周部に、内側リング中心方向に向かって、先端部５ｆが楔状の矩体突起部５ｅを、枠体５ａと一体に形成し、この突起部５ｅは、漏液検知用投射光の吸収材／透光材で形成するのが好ましく、突起部５ｅの底面５ｇは、床面１と密着せず、床面１との間に、所定の隙間ｄ６＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）の平行空隙部ｄ６を形成し、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａを、平行空隙部ｄ６の毛管現象を利用して、床面１に対向する底面５ｇに、高速に拡散せしめるようになっており、又、底面５ｇの一端で突起部５ｅの先端部５ｆは、ケース１２の全反射面１２ｍとの間に、所定の隙間ｄ７＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）の平行空隙部ｄ７を形成し、及び／又は、下端部の最大隙間ｄ７＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）で上方に向けて漸次狭くなる楔状空隙部ｄ７を形成し、かかる空隙部ｄ７の毛管現象を利用して、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａを、重力に抗して、漏液検知用反射境界面１２ｍの所定の漏液検知位置の上方まで床面１から、小量でも、直接速やかに引き上げ導くようになっている。
尚、空隙部ｄ７には、切断片８ｄを有する漏液検知用薄紙８の一部分を介挿させることも可能であり、低表面張力の漏液２ａを検知する速度は、実験によると、薄紙８が空隙部ｄ７に介在させてあっても、無くても、ほぼ同程度の検知速度であった。又、ケース１２全体は、リング状枠体５ａの上面内周部に複数箇所立設して設けられた嵌合係止部５ｎに挿入／装着により嵌合されて、回転自在に固定されるようになっており（図２（Ａ），（Ｂ））、係止部５ｎの先端部５ｐには、斜め上方にテーパ面を形成し、ケース１２の着脱操作が、ワンタッチで可能な構造が好ましい（図４（Ｂ））。
【０００７】
かかる構成において漏液センサ２０ａの動作を図３（Ｃ）及び図５を参照して説明すると、先ず、ケース１２がホルダ５や圧接手段６０により、しっかりと床面１に固定されていない場合には、ケース１２とホルダ５とが、浮いたり、斜めに傾斜したり、転倒した設置異常状態となり、このため光学式設置異常検知手段７０の投射光／反射光の光学経路２２ｚ／２４ｚが正常な位置に形成できず、光源手段１４ｃの投射光２２ｚは、本体部１２ｄの光学的境界面１２ａから空気等の気体層に透過／拡散して、反射部材（薄紙８）に到達しないか、又は、所定の角度以上に曲げられて投射され、その反射光２４ｚは、ほとんど受光手段１６ｃに到達しなくなるので、大幅に減少した受光手段１６ｃの出力を検知手段１８により正常な反射光レベルと比較することにより、容易に漏液センサ２０ａの設置異常が検知され、ＭＰＵ等からなる制御手段３０を介して設置異常アラーム信号（又はエラーコードＥＲ−Ａ）がケーブル２６により外部に出力され、図示しない電源制御部により、光源手段１４ａ，１４ｃ及び受光手段１６、１６ｃへの電源供給が停止され、漏液センサ２０ａはエラー待機状態となる。
かかるアラーム信号の出力されない通常の状態では、電源制御部から、光源手段１４ａ，１４ｃ及び受光手段１６、１６ｃへ電源が供給され、漏液センサ２０ａは作動状態となり、いかなる漏液も存在しない場合には、図３（Ｃ）に示すように光学式設置異常検知手段７０の投射光／反射光の光学経路２２ｚ／２４ｚが正常な位置に形成され、光源手段１４ｃからの投射光２２ｚが、ホルダ底面５ｊに載置された反射材（薄紙８）の反射面で反射され、その反射光２４ｚが受光素子１６ｃに入力され、その出力を検知手段１８により正常な反射光レベルと比較することにより、容易に漏液センサ２０ａの正常設置状態が検知される。又、漏液検知用光学系を形成する光源手段１４ａからの投射光２２ｕが、第１の全反射面１２ｍに上方から下方に全反射面１２ｍで所定の臨界角以上で全反射するように、透明材又は半透明材１２ｄの屈折率に応じた所定の入射角で照射され、その全反射光２２ｖが第２の全反射面１２ｎに投射され、全反射面１２ｎからの全反射光２４ｕが、透明材又は半透明材１２ｄの屈折率に応じた所定の受光角度で受光手段１６で受光され、かかる光学経路を伝搬した漏液検知光が光電変換素子により電気信号に変換され、その出力が、検知手段１８を兼ねた制御手段３０内で、デジタル処理されたり、受光手段１６のアナログ出力が、直接、アナログ比較器等から成るアナログ演算手段に入力され、アナログ回路から構成された検知手段１８を兼ねた制御手段３０内で、アナログ処理される。尚、漏液が存在しない場合には、上記例では、何れの受光手段でも正常な受光量が検知され、受光量の低下現象は発生しない。
【０００８】
次に、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａが、床面１に薄膜状に拡散してきた場合には、高速漏液引込手段６の一部を形成する矩体突起部５ｅの底面５ｇに対向する床面１の領域まで、液位ｄ１の漏液２ａが拡散してきた時点で、床面１と底面５ｇとの間に形成された平行空隙部ｄ６により、空隙部ｄ６の間隔と漏液２ａの液位ｄ１との長さを、略同程度の長さ、又は、液位ｄ１＞間隔ｄ６の長さに設定しておくと、空隙部ｄ６の毛管現象を利用して、漏液２ａが平行空隙部ｄ６に急速に引き込まれ（図５の２ａ１）、漏液２ａが底面５ｇに接触すると共に、床面１に対向する底面５ｇ全体に、高速に拡散される。
その後、底面５ｇの一端で、突起部５ｅの先端部５ｆの一端を形成する最下端部まで漏液２ａが拡散すると（図５の２ａ２）、漏液２ａは、更に、ケース１２の全反射面１２ｍと先端部５ｆとで形成された平行空隙部ｄ７の一端に到達し、空隙部ｄ７は、所定の隙間ｄ７で漏液２ａの毛管現象が発現するように設定されているので、漏液２ａの漏れ量が小量であっても、重力に抗して、漏液検知用反射境界面１２ｍの所定の漏液検知位置より上方まで、床面１から直接速やかに引き上げ導かれる（図５の２ａ３）。かくして、漏液２ａが、漏液検知用反射境界面１２ｍの所定の漏液検知位置を上方に通過すると、光源手段１４ａからの投射光２２ｕの大半の光は、全反射面１２ｍで全反射せず、底部１２ｄ及び全反射面１２ｍを、大略直進し、更に、空隙部ｄ７に充満した漏液２ａを屈折直進した後、投射光の吸収材／透光材で形成された矩体突起部５ｅ及び空隙部ｄ６に充満した漏液２ａ中を大略直進して、床面１で反射され、全反射面１２ｎと反対方向に伝搬・進行する。
従って、漏液検知用光学経路の一部を形成する全反射面１２ｍで全反射し、その後全反射面１２ｎでも全反射された光２４ｕが、受光手段１６で受光される光量は、大幅に低下し、その出力を制御手段３０により演算処理して、小量の漏液２ａが、床面１に薄く拡散し始めた非常に初期の段階で、非常に高速に検知することができる。又、低表面張力の漏液２ａが、床面１に一度に大量に漏れだした場合には、ケース１２の外周は全て漏液２ａで水浸しになり、かつ、漏液検知用反射境界面１２ｎの所定の漏液検知位置も漏液２ａ中に水没するので、光源手段１４ａからの投射光２２ｕが、全反射面１２ｍで全反射され、その全反射光２２ｖが全反射面１２ｎに投射されても、漏液２ａのために全反射面１２ｎで全反射せず、直ちに、全反射面１２ｎを大略直進し、更に、空隙部ｄ４に充満した漏液２ａの中を屈折直進した後、床面１で反射され、受光手段１６の設置位置と全く関係ない方向に伝搬・進行する。従って、漏液検知用光学経路の一部を形成する全反射面１２ｎで全反射された光２４ｕが、受光手段１６で受光される光量は、大幅に低下し、その出力を制御手段３０により演算処理して漏液２ａの大量発生を、非常に初期の段階で、非常に高速に検知することができる。
かくして、漏液検知手段１８を兼ねた制御手段３０により、漏液２ａ及び／又は２が検出されると、表示手段２９を赤色点灯させると共に、ケーブル２６を介して外部に漏液の有無を出力する（漏液検知エラーコードＥＲ−Ｂ）。
【０００９】
次に、２０℃で、６０ｄｙｎｅｓ／ｃｍ以上の表面張力の漏液２（図１（Ｅ）に示すような）が、床面１に拡散してきた場合には、液位ｄ３の漏液２が、床面１とケース底部１２ｄとの間に形成された平行空隙部ｄ４には、薄紙８が介挿されているので、薄紙８の外周部又は一部に、漏液２が接触した（図５）直後に、漏液２が薄紙８の全面に浸透／拡散し、漏液２が薄紙８を介して全反射面１２ｎ近傍まで急速に引き込まれる。かくして、漏液２が、漏液検知用反射境界面１２ｎの所定の漏液検知位置に到達すると、光源手段１４ａからの投射光２２ｕは、全反射面１２ｍで全反射され、その全反射光２２ｖが全反射面１２ｎでは、漏液２のために全反射せず、全反射面１２ｎを、大略直進し、更に、漏液２の浸透した薄紙８の中を屈折直進した後、床面１で反射され、受光手段１６の設置位置と全く関係ない方向に伝搬・進行する。従って、漏液検知用光学経路の一部を形成する全反射面１２ｎで全反射された光２４ｕが、受光手段１６で受光される光量は、大幅に低下し、その出力を制御手段３０により演算処理して漏液２を、床面１に薄く拡散し始めた非常に初期の段階で、非常に高速に検知することができる。
又、一度に大量の漏液２が発生した場合には、ケース１２の外周は全て漏液２で水浸し、かつ、漏液検知用反射境界面１２ｎの所定の漏液検知位置も漏液２中に水没するので、光源手段１４ａからの投射光２２ｕが、全反射面１２ｍで全反射され、その全反射光２２ｖが全反射面１２ｎに投射されても、漏液２のために全反射面１２ｎでは全反射せず、直ちに、全反射面１２ｎを大略直進し、更に、空隙部ｄ４に充満した漏液２の中を屈折直進した後、床面１で反射され、受光手段１６の設置位置と全く関係ない方向に伝搬・進行する。従って、漏液検知用光学経路の一部を形成する全反射面１２ｎで全反射された光２４ｕが、受光手段１６で受光される光量は、大幅に低下し、その出力を制御手段３０により演算処理して、漏液２の大量発生を、非常に初期の段階で、非常に高速に検知することができる。
かくして、漏液検知手段１８を兼ねた制御手段３０により、漏液２ａ又は２が検出されると、表示手段２９を赤色点灯させると共に、ケーブル２６を介して外部に漏液の有無を出力する（漏液検知エラーコードＥＲ−Ｂ）。尚、上述の受光処理では、レンズ、凹面鏡等の集光手段により広く反射光を集めることにより、受光手段（素子）１６、１６ｃの感度を向上させることも可能である。
更に又、漏液センサ２０ａでは、ケース１２とホルダ５との間に、薄紙８を介挿しているので、床面１に拡散してきた漏液２が、薄紙８を順次浸透して、薄紙８を透明層に変換しながら拡散し、リング状枠体５ａの内周側に設けられた突起部５ｈの上面に形成された載置平面５ｊまで漏液２が浸透し拡散すると、第３の光学的（反射）境界面である薄紙８に対し、ケース底部１２ｄから照射された光２２ｚが、薄紙８の表面では反射せず、そのまま漏液の浸透した薄紙８の中を直進し、更に、光の吸収材／透光材で形成された載置平面５ｊの内部に、所定の屈折角で直進するので、受光手段１６ｃにより受光される反射光２４ｚの光量が大幅に減少し、ケースの設置異常検知手段７０としての制御手段３０が作動し、ケースの設置異常エラーとして、漏液２が検知可能である。従って、漏液検知用の第１の光学系が故障して正常に動作しない場合でも、ケースの設置異常エラーとして、漏液２が検知可能となり、センサのエラー検知機能を、一段と向上させることができる。
【００１０】
かくして、図２（Ｂ）及び図５の漏液センサ２０ａは、漏液が浸透し得る気体層ｄ６、ｄ７又は漏液浸透層（例えば、図５では、床面１と底面１２ｐとに挟持された薄紙８の一部）を介して、前記漏液と接触し得る少なくとも１つの漏液検知用反射境界面１２ｍ，１２ｎと、光源手段１４ａ、受光手段１６及びこれらに結合された制御手段３０とから成る漏液センサの一種であり、気体層ｄ６又は漏液浸透層（ｄ４又は床面１と底面１２ｐとに挟持された薄紙８）の床面１に対向する面の一部又は全体を、直接、床面１に開放し（図５の例では、気体層ｄ６は、床面側全体）、又は、気体層又は漏液浸透層の一部として床面を構成せしめ（例えば、図５では、床面１と底面１２ｐとに挟持された薄紙８の一部）、更に、表面張力が、２０℃において、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａを、所定の隙間ｄ０及び所定の断面形状の毛管現象を発現しうる空隙部を利用して、重力に抗して、漏液検知用反射境界面１２ｍまで床面１から、小量でも、直接速やかに引き上げ導くための高速漏液引込手段６を、少なくとも１つ具え、光源手段１４ａの投射光２２ｕを漏液検知用反射境界面１２ｍに照射し、反射境界面１２ｍからの反射光を受光手段１６で受光し、その出力を制御手段３０により演算処理して、低表面張力の漏液２ａの有無を速やかに判定できるようにした漏液センサということができる。
又、図２（Ｂ）及び図５の漏液センサ２０ａは、漏液に接触し得る少なくとも２つの漏液検知用全反射境界面１２ｍ，１２ｎを、気体層ｄ６、ｄ７又は漏液浸透層（例えば、図５では、床面１と底面１２ｐとに挟持された薄紙８の一部）を介在させて形成し、少なくとも１つの光源手段１４ａ、受光手段１６及びこれらに結合された制御手段３０を、各反射境界面のそれぞれに対し、同一の側に配設し、第１の全反射境界面１２ｍに対しては光源手段１４ａから光２２ｕを投射し、第１の全反射境界面１２ｍからの反射光２２ｖを第２の全反射境界面１２ｎに投射し、第２の全反射境界面１２ｎからの反射光２４ｕを受光手段１６で受光し、その出力を制御手段３０により演算処理して漏液を検知するようにした漏液センサの一種であり、気体層ｄ６，ｄ７又は漏液浸透層の床面１に対向する面の一部又は全体を、直接、床面１に開放し、又は、気体層又は漏液浸透層の一部として床面１を構成せしめ、更に、表面張力が、２０℃において、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａを、所定の隙間ｄ０及び所定の断面形状の毛管現象を発現しうる空隙部を利用して、重力に抗して、漏液検知用反射境界面１２ｍまで床面１から、小量でも、直接速やかに引き上げ導くための高速漏液引込手段６を、少なくとも１つ具え、低表面張力の漏液２ａの有無を、小量の漏れ量でも、速やかに判定できるようにした漏液センサということもできる。
尚、上記毛管現象を発現しうる空隙部の所定の隙間ｄ０としては、低表面張力の漏液２ａを、小量、床面１に垂らした場合の、図１（Ｃ）に示す漏液２ａの厚さｄ１と同等の長さ、又は、これより小さい（ｄ０＜ｄ１）長さであって、漏液２ａの毛管現象を安定的に発現可能な長さが好ましく、又、上記毛管現象を安定的に発現しうる空隙部の所定の断面形状としては、例えば、隙間ｄ０以下の平行空隙部断面、及び／又は、最大隙間ｄ０以下で上方に向けて漸次狭くなる楔状空隙部断面等が利用可能であり、毛管現象を安定的に発現しうる断面形状であれば、いかなる形状のものでも利用可能である。
【００１１】
次に、図２及び図５に対応させて示す図６は、この発明の漏液センサ２０ｂの別の一実施例を示すものであり、それぞれ同一の番号を付した装置は同一の機能を果たすと共に、ケース１２側のみで高速漏液引込手段６ｂを構成し、かつ、漏液検知部に電気配線を無くし、電気的発火／引火の事故が絶対発生しない防爆構造を実現すると共に、ホルダ５を不要とし、センサケース単体で作動可能なように構成したもので、光ファイバ等の第１の光伝送手段４０ａ、４０ｃにより、遠隔地の制御部３９に別途隔離して設けられた光源手段１４から、投射光２２ｘ，２２ｚをそれぞれ伝送し、光伝送手段４０ａ、４２ａにより反射境界面１２ｍ，１２ｎへの光の投受光を行なう第１の光学系を形成し、光伝送手段４０ｃ、４２ｃにより、後述する高速漏液引込手段６ｂの上面に形成された反射載置面５ｊ（この例では、面５ｊは、薄紙８を利用しないので光反射材（白色又は鏡面）を使用するのが好ましい）への光の投受光を行なう第２の光学系（光学式設置異常検知手段７０ｂの光学経路）を形成するようにしたため、漏液検知用液体２／２ａが揮発性で引火、爆発の危険がある場合でも、極めて安全に漏液検知ができるようにしたものである。
則ち、上述の第１の光学系では、遠隔地に設けられた光源手段１４からの照射光の一部が、光伝送手段４０ａによりケース１２内に導かれ、全反射を生ずるような臨界角以上の所定の角度で、ケース底部の反射境界面１２ｍへ投射光２２ｕとして照射され、反射境界面１２ｎで更に全反射され、その反射光２４ｕは、光伝送手段４２ａにより受光され、遠隔地に設けられた受光素子１６に伝送され、マルチプレクサ３１、ＡＤ変換手段３２、ダブルバッファ３４を介して検知手段を兼ねた制御手段３０に入力されるようになっている。又、上述の第２の光学系では、遠隔地に設けられた光源手段１４からの照射光の他の一部が、光伝送手段４０ｃによりケース１２内に導かれ、臨界角以内又は臨界角以上の所定の角度で、反射部材５ｊへ投射光２２ｚとして照射され、その反射光２４ｚは光伝送手段４２ｃにより受光され、遠隔地に設けられた受光素子１６ｃに伝送され、マルチプレクサ３１、ＡＤ変換手段３２、ダブルバッファ３４を介して検知手段を兼ねた制御手段３０に入力されるようになっている。更に、ケース１２の底部は、透明材又は半透明材からなる透過光部材１２ｄを基材として構成し、その外側を光の照射面及び反射面／受光面を除いて遮光性の合成樹脂等の遮光材で被覆又は構成し、透過光部材１２ｄと一体成形するのが好ましく、かかる遮光部材を使用すると、ホルダ５がなくても周囲ノイズ光の影響を受けにくく、又漏液浸入時に床面が白色又は鏡面であっても不要な反射光を床面から受光しないような光学的構造が実現できる。
更に図６の例では、ケース１２側のみで高速漏液引込手段６ｂを構成するようになっており、その構成は、例えば、ケース底部１２ｄと床面１との間に、ケース１２の中心方向に向かって、先端部１２ｖが楔状の矩体突起部１２ｕを、ケース底部１２ｄに対して、透明材又は半透明材で構成し、かつ、本体部１２ｄと高速漏液引込手段６ｂとに折曲／分割可能な一体成形された合成樹脂材で構成するようになっている。この突起部１２ｕは、漏液検知用投射光の吸収材／透光材で形成するのが好ましく、突起部１２ｕの底面１２ｗは、床面１と密着せず、床面１との間に、所定の隙間ｄ６＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）の平行空隙部ｄ６を形成し、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａを、平行空隙部ｄ６の毛管現象を利用して、床面１に対向する底面１２ｗに、高速に拡散せしめるようになっており、又、底面１２ｗの一端で突起部１２ｕの先端部１２ｖは、ケース１２の全反射面１２ｍとの間に、所定の隙間ｄ７＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）の平行空隙部ｄ７を形成し、及び／又は、下端部の最大隙間ｄ７＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）で上方に向けて漸次狭くなる楔状空隙部ｄ７を形成し、かかる空隙部ｄ７の毛管現象を利用して、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａを、重力に抗して、漏液検知用反射境界面１２ｍの所定の漏液検知位置の上方まで床面１から、小量でも、直接速やかに引き上げ導くようになっている。
かかる一体成形用の合成樹脂部材としては、一般の熱可塑性プラスチック樹脂や熱可塑性エラストマーが利用でき、熱可塑性プラスチック樹脂としては、例えば、ポリエチレンテレフタレ−ト、非晶性ポリエチレンテレフタレ−ト、ポリエチレン、ポリスチレン、ポリプロピレン等が使用でき、また、一体成形用の熱可塑性エラストマーとしては、ポリブタジエン樹脂が使用可能である。
具体的には、ケース底部は、本体部１２ｄと高速漏液引込手段６ｂとがヒンジで連結されて一体に形成され、本体部１２ｄと高速漏液引込手段６ｂとが外周縁でＶ字状の溝部により連結され、合成樹脂材、すなわち、熱可塑性プラスチック樹脂または熱可塑性エラストマーにより一体成形されるようになっており、Ｖ字状の溝部を介して、全反射面１２ｍ側に折曲すると、面１２ｖの先端部側に形成した所定の高さｄ７の複数の小突起を介して空隙部ｄ７を形成し、又、高速漏液引込手段６ｂの面１２ｗ側に形成された所定の高さｄ６の複数の小突起を介して、折曲した場合に床面１との間で空隙部ｄ６を形成すると共に、反発力を生成する開閉機構を構成するようになっている。従って、ケースの本体部１２ｄと高速漏液引込手段６ｂとを全反射面１２ｍ側に折曲して、ケース１２の設置面に対して略水平状態に閉じたときには、自重または外部からの圧接手段６０により本体部１２ｄと高速漏液引込手段６ｂとが空隙部ｄ７を形成した状態を維持でき、かつ、光学式設置異常検知手段７０ｂの光学経路の一部を形成するようになっている。則ち、水平な床面１にケース１２を設置した場合は、ケース１２の設置面は、水準器等から規定される基準水平面に対し水平／平行となる。
【００１２】
かかる構成において、その動作を次に説明すると、図５の高速漏液引込手段６と、図６の高速漏液引込手段６ｂとでは、高速漏液引込手段６及び６ｂの構成が、薄紙８を使用せず、又、光学経路の一部に、投光／受光用の光伝送手段が、それぞれ、追加されている点を除いては、全く同様であるから、その動作も、基本的に全く同様である。
具体的には、先ず、光学式設置異常検知手段７０ｂでは、光源手段１４ー光伝送手段４０ｃからの投射光２２ｚが、高速漏液引込手段６ｂの上面に設けられた反射材５ｊに、臨界角未満の入射角で照射され、その反射光２４ｚが光伝送手段４２ｃー受光手段１６ｃにより受光され、電気信号に変換されて制御手段３０に入力されるようになっている。尚、白色または鏡面状等の反射材５ｊに基づく反射面は、突起部１２ｕの上面に設けることが可能であり、突起部１２ｕに接着、溶融、圧入して形成するようにし、又は、突起部１２ｕの上面に凸凹の反射面を刻設して、投射光２２ｚの反射面を形成してもよい。
一方、ケース１２の本体部１２ｄと突起部１２ｕとが所定の間隔で空隙部ｄ７を形成していない場合は、上記ヒンジ機構から生成される反発力により、本体部１２ｄと突起部１２ｕとが、浮いたり、斜めに傾斜したり、転倒した設置異常状態となり、本体部１２ｄと突起部１２ｕとが間隔ｄ７以上に開いた状態を維持できる開閉機構が予めケース１２には付勢されており、このため設置異常状態では、正常な第２の光学経路が形成されず、投射光が空気等の気体層に拡散し、上述の光学式設置異常検知手段７０ｂの投射光および反射光の光学経路２２ｚ／２４ｚが、正常な位置に形成できず、容易にケース１２の設置異常が検知され、ＭＰＵ等からなる制御手段３０を介して設置異常アラーム信号（又はエラーコードＥＲ−Ａ）がケーブル２６により外部に出力され、漏液センサ２０ｂはエラー待機状態となる。
かかるアラーム信号の出力されない通常の状態では、漏液センサ２０ｂは作動状態となり、いかなる漏液も存在しない場合には、図３（Ｃ）に示すように光学式設置異常検知手段７０ｂの投射光／反射光の光学経路２２ｚ／２４ｚが正常な位置に形成され、光源手段１４ー光伝送手段４０ｃからの投射光２２ｚが、突起部１２ｕの反射面５ｊで反射され、その反射光２４ｚが、光伝送手段４２ｃを介して伝送され、受光素子１６ｃに入力され、その出力を検知手段１８により正常な反射光レベルと比較することにより、容易に漏液センサ２０ｂの正常設置状態が検知される。
又、漏液検知用光学系を形成する光源手段１４ー光伝送手段４０ａからの投射光２２ｕが、第１の全反射面１２ｍに上方から下方に全反射面１２ｍで所定の臨界角以上で全反射するように、透明材又は半透明材１２ｄの屈折率に応じた所定の入射角で照射され、その全反射光２２ｖが第２の全反射面１２ｎに投射され、全反射面１２ｎからの全反射光２４ｕが、透明材又は半透明材１２ｄの屈折率に応じた所定の受光角度で、光伝送手段４２ａの一端で受光され、光伝送手段４２ａを介して受光手段１６に伝送され、かかる光学経路を伝搬した漏液検知光が光電変換素子１６により電気信号に変換され、その出力が、検知手段１８を兼ねた制御手段３０内で、デジタル処理されたり、受光手段１６のアナログ出力が、直接、アナログ比較器等から成るアナログ演算手段に入力され、アナログ回路から構成された検知手段１８を兼ねた制御手段３０内で、アナログ処理される。尚、漏液が存在しない場合には、上記例では、何れの受光手段でも正常な受光量が検知され、受光量の低下現象は発生しない。
【００１３】
次に、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａが、床面１に薄膜状に拡散してきた場合には、高速漏液引込手段６ｂの一部を形成する矩体突起部１２ｕの底面１２ｗに対向する床面１の領域まで、液位ｄ１の漏液２ａが拡散してきた時点で、床面１と底面１２ｗとの間に形成された平行空隙部ｄ６により、空隙部ｄ６の間隔と漏液２ａの液位ｄ１との長さを、略同程度の長さ、又は、液位ｄ１＞間隔ｄ６の長さに設定しておくと、空隙部ｄ６の毛管現象を利用して、漏液２ａが平行空隙部ｄ６に急速に引き込まれ（図５の２ａ１）、漏液２ａが底面１２ｗに接触すると共に、床面１に対向する底面１２ｗ全体に、高速に拡散される。
その後、底面１２ｗの一端で、突起部１２ｕの先端部１２ｖの一端を形成する最下端部まで漏液２ａが拡散すると（図５の２ａ２）、漏液２ａは、更に、ケース１２の全反射面１２ｍと先端部１２ｖとで形成された平行空隙部ｄ７の一端に到達し、空隙部ｄ７は、所定の隙間ｄ７で漏液２ａの毛管現象が発現するように設定されているので、漏液２ａの漏れ量が小量であっても、重力に抗して、漏液検知用反射境界面１２ｍの所定の漏液検知位置より上方まで、床面１から直接速やかに引き上げ導かれる（図５の２ａ３）。かくして、漏液２ａが、漏液検知用反射境界面１２ｍの所定の漏液検知位置を上方に通過すると、光源手段１４からの投射光２２ｕの大半の光は、全反射面１２ｍで全反射せず、底部１２ｄ及び全反射面１２ｍを、大略直進し、更に、空隙部ｄ７に充満した漏液２ａを屈折直進した後、投射光の吸収材／透光材で形成された矩体突起部１２ｕ及び空隙部ｄ６に充満した漏液２ａ中を大略直進して、床面１で反射され、全反射面１２ｎと反対方向に伝搬・進行する。従って、漏液検知用光学経路の一部を形成する全反射面１２ｍで全反射し、その後全反射面１２ｎでも全反射された光２４ｕが、光伝送手段４２ａの一端で受光され、光伝送手段４２ａを介して受光手段１６に伝送された受光光量は、大幅に低下し、その出力を制御手段３０により演算処理して、小量の漏液２ａが、床面１に薄く拡散し始めた非常に初期の段階で、非常に高速に検知することができる。
又、低表面張力の漏液２ａが、床面１に一度に大量に漏れだした場合には、ケース１２の外周は全て漏液２ａで水浸しになり、かつ、漏液検知用反射境界面１２ｎの所定の漏液検知位置も漏液２ａ中に水没するので、光源手段１４からの投射光２２ｕが、全反射面１２ｍで全反射され、その全反射光２２ｖが全反射面１２ｎに投射されても、漏液２ａのために全反射面１２ｎで全反射せず、直ちに、全反射面１２ｎを大略直進し、更に、空隙部ｄ４に充満した漏液２ａの中を屈折直進した後、床面１で反射され、光伝送手段４２ａの設置位置と全く関係ない方向に伝搬・進行する。従って、漏液検知用光学経路の一部を形成する全反射面１２ｎで全反射された光２４ｕが、光伝送手段４２ａの一端で受光される光量は、大幅に低下し、光伝送手段４２ａを介して受光手段１６に伝送された受光出力を制御手段３０により演算処理して漏液２ａの大量発生を、非常に初期の段階で、非常に高速に検知することができる。
かくして、漏液検知手段１８を兼ねた制御手段３０により、漏液２ａ及び／又は２が検出されると、表示手段２９を赤色点灯させると共に、ケーブル２６を介して外部に漏液の有無を出力する（漏液検知エラーコードＥＲ−Ｂ）。
【００１４】
次に、２０℃で、６０ｄｙｎｅｓ／ｃｍ以上の表面張力の漏液２（図１（Ｅ）に示すような）が、床面１に拡散してきた場合には、図６の例では、液位ｄ３の漏液２が床面１とケース底部１２ｄとの間に形成された平行空隙部ｄ４に拡散していっても、薄紙８が介挿されていないので、そのまま床面１を全反射面１２ｎの方向に拡散していく。かくして、漏液２が、漏液検知用反射境界面１２ｎの所定の漏液検知位置に到達すると、光源手段１４ー光伝送手段４０ａからの投射光２２ｕは、全反射面１２ｍで全反射され、その全反射光２２ｖが全反射面１２ｎでは、漏液２のために全反射せず、全反射面１２ｎを、大略直進し、更に、漏液２の中を屈折直進した後、床面１で反射され、光伝送手段４２ａの一端が設置されている所定の位置と全く関係ない方向に伝搬・進行する。従って、漏液検知用光学経路の一部を形成する全反射面１２ｎで全反射された光２４ｕが、光伝送手段４２ａの一端で受光される光量は、大幅に低下し、光伝送手段４２ａを介して伝送された受光手段１６の出力を制御手段３０により演算処理して、漏液２が床面１に薄く拡散し始めた非常に初期の段階で、非常に高速に検知することができる。
又、一度に大量の漏液２が発生した場合には、ケース１２の外周は全て漏液２で水浸し、かつ、漏液検知用反射境界面１２ｎの所定の漏液検知位置も漏液２中に水没するので、光源手段１４ー光伝送手段４０ａからの投射光２２ｕが、全反射面１２ｍで全反射され、その全反射光２２ｖが全反射面１２ｎに投射されても、漏液２のために全反射面１２ｎでは全反射せず、直ちに、全反射面１２ｎを大略直進し、更に、空隙部ｄ４に充満した漏液２の中を屈折直進した後、床面１で反射され、光伝送手段４２ａの一端が設置されている位置と全く関係ない方向に伝搬・進行する。従って、漏液検知用光学経路の一部を形成する全反射面１２ｎで全反射された光２４ｕが、光伝送手段４２ａを介して受光手段１６で受光される光量は、大幅に低下し、その出力を制御手段３０により演算処理して、漏液２の大量発生を、非常に初期の段階で、非常に高速に検知することができる。
かくして、漏液検知手段１８を兼ねた制御手段３０により、漏液２ａ又は２が検出されると、ケーブル２６を介して外部に漏液の有無を出力する（漏液検知エラーコードＥＲ−Ｂ）。尚、上述の受光処理では、レンズ、凹面鏡等の集光手段により広く反射光を集めることにより、受光手段（素子）１６、１６ｃの感度を向上させることも可能である。
【００１５】
従って図６に示すような構造の漏液センサ２０ｂによれば、漏液センサ２０ｂを床面１に置くだけで、ホルダ４、５や薄紙８がなくても外来光の影響をほとんど受けずに、かつ、漏液２ａや２が、ホルダ４の上面まで到達する以前の、床面１に小量だけ流出した漏液流出の初期段階で、素早く漏液を検出することができる利点がある。又、漏液検知部には電気信号が一切流れないので、揮発性の漏液に対しても、極めて安全に検出処理を行なうことができ、一度に大量の漏液が流出しても、この漏液を２重、３重にチェックして検出し、漏液検出処理の信頼性を一段と向上させることができると共に、光伝送手段４０／４２の長さを変更することにより、光源手段１４並びに受光手段１６、１６ｃ等と、反射境界面１２ｍ／１２ｎ等との物理的距離を所望の可変距離に変更することができる。
又、ケースの本体部１２ｄと突起部１２ｕとが所定の間隔ｄ６，ｄ７を保持できない状態では、光学式設置異常検知手段７０ｂの光学経路が所定の位置に形成されず、ヒンジ機構から生成される反発力により、本体部１２ｄと突起部１２ｕとが、浮いたり、斜めに傾斜したり、転倒した設置異常状態となり、本体部１２ｄと突起部１２ｕとが開いた状態を維持できる開閉機構により、投射光の反射経路が大きく曲げられるので、設置異常状態が容易に検知することができ、漏液エラーと設置異常エラーとを区別して検知すると共に、伝送したり、対処することができる。
尚、図６の漏液センサ２０ｂでも、図５と同様に薄紙８を使用することは可能である。
【００１６】
次に、図２、図５及び図６に対応させて示す図７（Ａ）は、本発明の漏液センサ２０ｃの又別の一実施例を示すものであり、それぞれ同一の番号を付した装置は同一の機能を果たすと共に、図５のケース１２の底部下方を、ケース本体と、ホルダ５０とに、光学的に分割し、ホルダ５０側のみで高速漏液引込手段６ｃを構成したもので、
その構成は、枠体５ａの内周部に、内側リング中心方向に向かって、先端部５ｆが楔状の矩体突起部５ｅを、枠体５ａと一体に形成し、この突起部５ｅは、漏液検知用投射光の吸収材／透光材で形成するのが好ましく、突起部５ｅの底面５ｇは、床面１と密着せず、床面１との間に、所定の隙間ｄ６＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）の平行空隙部ｄ６を形成し、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａを、平行空隙部ｄ６の毛管現象を利用して、床面１に対向する底面５ｇに、高速に拡散せしめるようになっており、又、底面５ｇの一端で突起部５ｅの先端部５ｆは、ホルダ５０の全反射面５ｓとの間に、所定の隙間ｄ７＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）の平行空隙部ｄ７を形成し、及び／又は、下端部の最大隙間ｄ７＝１ｍｍ以下（好ましくは、０．９ｍｍ以下、より好ましくは、０．５ｍｍ以下）で上方に向けて漸次狭くなる楔状空隙部ｄ７を形成し、かかる空隙部ｄ７の毛管現象を利用して、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａを、重力に抗して、漏液検知用反射境界面５ｓの所定の漏液検知位置の上方まで床面１から、小量でも、直接速やかに引き上げ導くようになっている。尚、空隙部ｄ７には、切断片８ｄを有する漏液検知用薄紙８の一部分を介挿させることも可能である。
又、漏液検知用光学系は、透明部材又は半透明部材で構成されたケース１２の底部１２ｄの下方に、底部１２ｄと光学的に分割可能、かつ、一体に構成されたホルダ５０を設け、ホルダ５０には、所定の傾斜角度で平面状の全反射面５ｓ，５ｔを設け、これらの平面状全反射面５ｓ及び５ｔは、その先端部がコーナーキューブと同等の機能を果たすように、その延長が相互に交差するように形成し、光源手段１４ａからの投射光２２ｕが、全反射面５ｓに略鉛直上方から下方に照射され、その反射光２２ｖが全反射面５ｔに投射され、全反射面５ｔの反射光２４ｕが受光手段１６で受光され、電気信号に変換されるようになっている。
かかる構成において漏液センサ２０ｃの高速漏液引込手段６ｃ動作は、図５の高速漏液引込手段６の動作と、全く同様である。
【００１７】
次に、図４（Ａ），（Ｂ）及び図７（Ａ）に対応させて示す図７（Ｂ）〜（Ｄ）は、本発明の高速漏液引込手段６ｄの別の一実施例を示すものであり、それぞれ同一の番号を付した装置は同一の機能を果たすと共に、ホルダ４ｊ側のみで高速漏液引込手段６ｄを構成したもので、その構成は、ホルダ４ｊの枠体４ｋの内側に、内側中心に向かって、Ｙ字状アーム４ｍが、枠体４ｋと一体に形成され、アーム４ｍに透明材からなる断面が皿状殻体８ｋが、床面１と所定の間隔ｄ６で空隙部ｄ６を形成するように外周外延部８ｍが形成され、更に、アーム４ｍの外周に沿って、所定の個数の微小突起を介して間隔ｄ８で、キャプ部８ｎがその上面が水平に、透明材／半透明材で形成され、殻体８ｋの内側上面で漏液検知用反射面８ｐの領域には、白色の乱反射面が形成され、アーム４ｍと殻体８ｋとの対向部には、低表面張力の漏液２ａが、毛管現象により拡散可能な空隙部ｄ８が形成され、重力に抗して、床面１から、直接、漏液２ａを乱反射面８ｐまで引き込み可能となっており、アーム４ｍの床面１に対向する面の各エッジ部には、止水材４ｑが貼着又は固定され、空隙部ｄ２に漏液２ａが拡散／浸透するのを防止するようになっている。
従って、漏液２ａが反射領域８ｐに存在しない場合には、投射光２２ｕが反射面８ｐで乱反射され、白色反射光２４ｕが、受光手段１６で検知可能であるが、漏液２ａが毛管現象により床面１から空隙部ｄ６，ｄ８を介して、反射領域８ｐに引き上げられた場合には、乱反射面８ｐが漏液２ａにより透明となるので、投射光２２ｕが殻体８ｋを透過し、アーム４ｍの上面で吸収され、反射面８ｐからの反射光２４ｕの光量が激減し、受光手段１６の受光量が激減するので、漏液の検知が可能となる。かかる構成の高速漏液引込手段６ｄでも、高速漏液引込手段６と同等の効果を期待できる。
【００１８】
【発明の効果】
以上説明したように、本発明の漏液センサ２０ａ、２０ｂ等によれば、床面に対向したセンサケース及び／又はホルダに、床面１を空隙部の構成要素として含む毛管現象の発現可能な高速漏液引込手段６、６ｂ，６ｃ等を設けるようにしたので、小量の低表面張力を有する漏液が床面１に薄膜状に拡散した非常に初期の段階で、重力に抗して、漏液検知用反射境界面の漏液検知位置まで床面から、直接速やかに引き上げ導くことができ、漏液２ａがホルダ上面４ａを乗り越える水位まで上昇するのに必要な時間まで待たなくても、非常に高速に漏液検知が可能となり、又、漏液２ａがホルダ上面４ａを乗り越えるのに十分な漏液量が確保できなくても、毛管現象により、非常に小量の漏液２ａでも、高速に漏液検知ができるといった利点がある。
又、本発明の漏液センサ２０ａによれば、２０℃で、６０ｄｙｎｅｓ／ｃｍ以下である低表面張力の漏液２ａが、床面１に、小量、薄膜状に拡散し始めた非常に初期の段階で、高速漏液引込手段６により、毛管現象を利用して、小量の漏液２ａを、重力に抗して、漏液検知用反射境界面１２ｍの所定の漏液検知位置の上方まで、床面１から直接速やかに引き上げ導くことができるので、従来のホルダ上面４ａまで漏液２ａの液位が上昇し、更に、所定の漏液検知高さまで漏液が大量に流出する期間中、漏液センサの漏液検知動作が休止状態となることが一切なく、床面に小量の漏液が発生した初期の段階で、非常に高速に漏液２ａを検知することが可能である。又、低表面張力の漏液２ａが、床面１に一度に大量に漏れだした場合にも、ケース１２の外周は全て漏液２ａ中に水没するので、全反射面１２ｎも瞬時に漏液２ａ中に水没し、漏液２ａのために全反射面１２ｎで漏液検知用投射光の全反射現象が起きず、直ちに、全反射面１２ｎでの全反射光２４ｕの受光量が大幅に低下し、その出力を制御手段３０により演算処理して漏液２ａの大量発生を、気泡の滞留等に全く影響されず、瞬時に検知することが可能である。
次に、２０℃で、６０ｄｙｎｅｓ／ｃｍ以上の表面張力の漏液２が、床面１に拡散し始めた非常に初期の段階で、薄紙８の外周部及び／又は一部に、漏液２が接触した直後に、漏液２が薄紙８を介して全反射面１２ｎ近傍まで急速に引き込まれ、漏液２が、漏液検知用反射境界面１２ｎの所定の漏液検知位置に到達すると、全反射面１２ｎでは、薄紙８に浸透した漏液２のために全反射光が殆ど発生せず、漏液検知用投射光は、全反射面１２ｎから漏液中に屈折直進するので、受光手段１６での受光量は大幅に低下し、その出力を制御手段３０により演算処理して、漏液２が床面１に小量だけ薄く拡散しはじめた非常に初期の段階で、非常に高速に検知することが可能である。又、漏液２が、床面１に一度に大量に漏れだした場合にも、ケース１２の外周は全て漏液２中に水没するので、全反射面１２ｎも瞬時に漏液２中に水没し、漏液２のために全反射面１２ｎで漏液検知用投射光の全反射が起きず、直ちに、全反射面１２ｎでの全反射光２４ｕの受光量が大幅に低下し、その出力を制御手段３０により演算処理して漏液２の大量発生を、気泡の滞留等に全く影響されず、瞬時に検知することが可能である。
又、ケース１２がホルダ５等にしっかりと固定されていない場合には、ケース１２の本体部１２ｄとホルダ５の載置面５ｊ上の薄紙８とが密着せず、本体部１２ｄと薄紙８とが、浮いたり、斜めに傾斜したり、転倒した設置異常状態となり、光学式設置異常検知手段７０の投射光／反射光の光学経路が正常な位置に形成できず、光源手段１４ｃの投射光２２ｚは薄紙８により所定の角度以上に曲げられて投射され、その反射光２４ｚは、ほとんど受光手段１６ｃに到達しなくなるので、受光手段１６ｃの出力を、検知手段１８により正常な反射光レベルと比較することにより、容易に漏液センサ２０ａの設置異常が検知できる。従って、通常、センサ２０ａの消費電力の半分以上を消費している光源手段１４ａ，１４ｂへの電力供給をただちにカットできるので、漏液センサの省エネ化が図れると共に、従来、区別できなかった漏液異常エラーとセンサの設置異常エラーとを明確に区別できるので、エラー発生信号の受信後、プラントの監視センター等では、それぞれ的確に各エラー状況に対処することができる。尚、設置異常検知手段７０は、検知対象となる漏液が、硫酸、塩酸、硝酸等の強酸や、可性ソーダ、可性カリ等の強アルカリ溶液の場合でも、正常かつ安定的に動作できる機構、構造の物が好ましく、漏液センサ２０ａは、ケース底部が、透明材又は半透明材で構成されているので、外部にいっさい電子部品等が露出しない構造を実現でき、耐薬品性に優れると共に、ケース１２とホルダ５とは、床面からの高さ一定であるが、回動自在に固定可能であるので、その着脱操作が非常に容易である。 又、防爆構造の安全な漏液センサも容易に提供可能である。
【図面の簡単な説明】
【図１】図１（Ａ）は、従来の薄紙を使用した光学式漏液センサの構造を示す図である。
図１（Ｂ）は、従来の漏液センサにおいて、薄紙の中央に気泡が滞留する原理を説明する図である。
図１（Ｃ）は、低表面張力の漏液２ａの液位ｄ１を説明する図である。
図１（Ｄ）は、漏液２ａが、ホルダ４と床面１の隙間ｄ２に拡散していくプロセスを説明する図である。
図１（Ｅ）は、比較的高い表面張力の漏液２の液位ｄ３を説明する図である。
【図２】図２（Ａ）は、本発明の漏液センサ２０ａの構造を示す平面図である。
図２（Ｂ）は、その２Ｂ−２Ｂでの、横断面図である。
図２（Ｃ）は、その側面図である。
【図３】図３（Ａ）は、その３Ａ−３Ａでの縦断面図である。
図３（Ｂ）は、図２（Ｂ）の拡大図である。
図３（Ｃ）は、その３Ｃ−３Ｃでの横断面図である。
【図４】図４（Ａ）は、本発明のホルダ５の平面図である。
図４（Ｂ）は、その中央横断面図である。
図４（Ｃ）は、切断部８ｄを有する薄紙８の平面図である。
【図５】本発明の高速漏液引込手段６の動作原理を示す拡大断面図である。
【図６】本発明の防爆型漏液センサ２０ｂの一例を示す図である。
【図７】図７（Ａ）は、本発明の別の高速漏液引込手段６ｃの１例を示す図である。
図７（Ｂ）は、本発明の又別の高速漏液引込手段６ｄの１例を示す平面図である。
図７（Ｃ）は、その中央横断面図である。
図７（Ｄ）は、高速漏液引込手段６ｄの動作原理を示す断面図である。
【符号の説明】
１ 床面
２ 漏液
４、４０ｂ、５、５０ ホルダ
４ａ ホルダ底面
６、６ｂ〜６ｄ 高速漏液引込手段
１２ｍ，１２ｎ、５ｓ，５ｔ 光学的境界面
８ 薄紙
１０、ｄ４〜ｄ８ 空隙部
１２ ケース
１２ｄ 透過光部材、半透過光部材
１４、１４ｂ 光源手段
１６、１６ｃ 受光手段
２０ａ〜２０ｄ 漏液センサ
２２ｕ、２２ｚ 投射光
２４ｕ、２４ｚ 反射光
３０ 制御手段
４０ａ、４０ｃ、４２ａ、４２ｃ 光伝送手段
７０ 設置異常検知手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a liquid leakage sensor capable of detecting a small amount of liquid having a low surface tension at a surface tension of 60 dynes / cm or less at 20 ° C. at a high speed.
[0002]
[Prior art]
In a conventional facility such as a factory, a liquid is supplied by piping. However, since connecting joints are provided at many places in the pipe, liquid often leaks from the joints. Therefore, depending on the type of liquid, a human had to constantly monitor the leakage. As such a conventional liquid leakage monitoring method, a conductive method and a liquid amount method are known. Japanese Patent Publication No. 4-70572 discloses that a light source illuminates a filter that becomes transparent when a liquid leak is absorbed, and detects a change in transmitted light or reflected light from the filter when a liquid leaks. A leak sensor technology that can reliably detect a leak is described.
FIG. 1A is a diagram showing the principle of such a conventional reflected light detection type liquid leakage sensor 20. A thin paper 8 and a holder for a case 12 (normally about 0.9 mm to 0.1 mm) are placed on the floor 1. A front and rear metal plate 4) is matted on its upper bottom surface 4a, plated with black, fixed with screws or other fasteners also as a reflection light absorbing plate, and a white thin paper (paper, cloth, glass) Alternatively, a synthetic resin member or the like may be used. When the liquid is not sucked, the light is reflected in white, and when the liquid is sucked, a transparent / light transmitting material 8 is placed. A case 12 having a bottom portion 12d made of a transparent or translucent synthetic resin material or a ceramic material such as glass is inserted / attached to the holder 4, and inside the case 12, light source means (light emitting portion) is provided. 14, a light receiving unit (photoelectric conversion unit) 16 and a detection unit (control unit, calculation unit) 18 including a comparator and the like are integrally accommodated and connected to the outside via a cable 26.
The case 12 blocks external noise light and also functions as a dustproof and waterproof cover. However, the case 2 facilitates the leakage of the liquid 2 into the central reflection area 8b of the thin paper 8 and detects the liquid leakage. In order to shorten the time, a minute gap (a gas layer is formed in a sensor that does not use thin paper) 10 is provided between the bottom surface 12a of the case bottom 12d and the thin paper 8, and the holder bottom 4a is formed. The parallel gap d with the case bottom surface 12a forms a liquid leakage permeable layer that sucks the liquid leakage. The gap d is preferably several mm or less in order to avoid dirt such as dust and dust, and to stably detect reflected light from the thin paper 8 without detecting external noise light. It has been found that the use of a filter having a structure that can be attached to and detached from the case 12 facilitates replacement of the thin paper 8 and installation work. In addition, since the location of the leak is generally not specified, the thin paper is generally preferably circular in shape to quickly respond to the leak from any direction. Was.
In such a configuration, the liquid leakage detection light 22 is normally irradiated from the light source means 14 such as an LED, an infrared light emitting element, a semiconductor laser, and an optical fiber for projecting light, and the white reflected light 24 from the thin paper 8 is reflected by the light receiving means. 16 is always detected. Thus, when the liquid 2 leaks on the floor surface 1, the liquid 2 permeates sequentially from the contact portion 9 into the reflection area 8b of the thin paper 8, and the contact portion 9 of the thin paper 8 becomes white due to the permeation of the liquid. Changes to a transparent color. However, since the reflecting plate 4a on the lower side of the thin paper 8 is black, the color of the thin paper 8 changes from white to black at the contact portion 9, and the reflected light 24 to the light receiving means (including the light receiving optical fiber) 16 is It is absorbed by the reflection plate 4a and greatly reduced, and the detection means (control means) 18 detects a change in the amount of reflected light to detect liquid leakage.
The liquid leakage sensor using such thin paper has a simple structure, is reliable in operation, and is fixed to the floor surface with a stopper or the like. Although there is an advantage that it can be detected in time, users who want to minimize the work of installing the holder on the floor and replacing the thin paper as much as possible have demanded a liquid leak sensor that does not use thin paper and does not require the floor installation work. .
[0003]
[Problems to be solved by the invention]
As an unnecessary liquid leakage sensor for the thin paper 8, the light source irradiates projection light at a predetermined incident angle from the light source means so as to generate total reflection light on the bottom surface 12a of the case bottom portion 12d, and the leakage light amount depends on the magnitude of the reflection light amount. Various devices for determining the presence or absence of liquid have been devised.However, if the case bottom and the floor are brought into close contact with each other, a highly viscous liquid becomes very difficult to penetrate into the center of the case bottom.
(A) In general, a liquid leakage sensor that is unnecessary for the thin paper 8 and is configured to generate total reflection light for liquid leakage detection on the bottom surface 12a of the case bottom 12d is smaller than a liquid leakage sensor that uses thin paper. And a gap of at least d = 2 to 4 mm is provided between the floor and the bottom of the case or between the upper surface of the holder 4a and the bottom of the case. The liquid leaks out, the liquid level (liquid level) of the liquid gradually rises, and after a very long time has passed since the time of the liquid leakage, the liquid was not detected until the bottom of the case came into contact with the liquid. There was a problem that it was not possible. Therefore, with a small amount (for example, 5 cc, preferably 2 cc) of liquid leakage, there is a problem that the leakage cannot be detected at all even after many hours.
(B) A sensor having a structure in which the bottom of the case is directly exposed to the floor without a holder / cap and having a reflective boundary surface for detecting liquid leakage outside the case body. Is easily affected by the paint color of the floor surface, and when the liquid has permeated, it receives a large amount of unnecessary reflected light from the floor surface and malfunctions. In this case, there is a problem that the determination of the presence or absence of liquid leakage is not stable.
(C) Further, as a cleaning agent / solvent, for example, when detecting leakage of a liquid having a low surface tension of not more than 60 dynes / cm at 20 ° C., in particular, a low molecule containing no chlorine or bromine When detecting a liquid leak 2a having a low surface tension of 30 dynes / cm or less at 20 ° C., such as chlorofluorocarbon (CFCs) or halon, the liquid leak 2a is very thin. As shown in FIG. 1 (C), the thickness d1 uniformly and quickly diffuses into a thin film having a thickness of 0.5 mm or less, and easily penetrates into very narrow gaps of 0.1 mm or less. Therefore, as shown in FIG. 1 (D), it takes a long time to first penetrate into the gap d2 (<d1) between the case holder 4 and the floor surface 1 and to diffuse the liquid leakage 2a to the upper surface of the holder. Cost, and as a result, Or could not liquid detected at all, a problem that delayed the detection of the leakage has occurred.
(D) On the other hand, in the case of the liquid leakage sensor using the thin paper 8, a gap / liquid leakage permeable layer is formed in which the gap d between the bottom surface 12a of the case bottom 12d and the upper surface 4a of the holder 4 is 1 mm or less. However, in order to reduce / eliminate the influence of the reflected light from the floor surface 1, the upper surface of the floor surface 1 corresponding to the liquid leakage detection area is always processed / formed so that the holder bottom surface 4a covers the floor surface 1. The thin paper 8 is placed on the thin paper 8, and the thin paper 8 does not constitute the liquid leakage sensor in a state where the thin paper 8 is in direct contact with the floor surface 1 corresponding to the liquid leakage detection area (FIG. 7 ( C)).
Therefore, when detecting the leak 2a of a highly volatile liquid having a low surface tension of 30 dynes / cm or less at 20 ° C., such as the above-mentioned CFCs or halon, with the conventional thin paper 8, first, the leak 2a Takes a time necessary for the liquid to rise to the water level of the holder upper surface 4a, and further, after a time necessary for the liquid leakage 2a to rise to a water level sufficient to get over the holder upper surface 4a, the holder upper surface 4a Above, the above-mentioned liquid leakage 2a easily permeates the conventional thin paper 8 in the vertical direction and evaporates quickly, so that the process of permeating and diffusing very slowly in the horizontal direction progresses, The speed at which the thin paper 8 changes transparently and propagates as a liquid leakage penetrating layer is extremely slow, and a long time is required. According to the experiments of the present inventor, compared with the thin paper permeating speed of a liquid having a large surface tension such as water. Then, about 1 It takes a long time of 100 times or more, and as a result, the problem that the detection time of the leaked liquid 2a having a low surface tension is greatly delayed from the time of occurrence of the leaked liquid, There was a problem that the amount of liquid leakage could not be secured to a water level sufficient for the 2a to climb over the upper surface 4a of the holder, and the liquid 2a could not be detected at all. When the leaked liquid 2 is water, it changes depending on the properties of the floor surface, the material, and the amount of the leaked liquid. However, according to the experiment of the present inventor, usually, as shown in FIG. It has been found that the height d3 of the liquid leakage surface changes in a range of about 2 mm to 7 mm.
In addition, the conventional optical liquid leak sensor also has the following problems that could not be expected at first.
(E) When the holder bottom surface 4a is horizontal on the floor surface 1 and the case bottom surface 12a is also installed in a substantially horizontal state, the high-pressure pipes and large-diameter pipes are damaged, and a large amount of liquid leakage / outflow occurs at one time. In this case, the lower portion of the case 12 is submerged in the liquid leakage almost all around. In this state, when the leaked liquid 2 starts to permeate sequentially from the outer edge of the thin paper 8 toward the inside thereof, a part of the gas existing in the gap 10 between the holder bottom surface 4a and the case bottom surface 12a becomes bubbles to form the case. Although the gas is discharged to the outside of the space 12, the gas in the vicinity of the center of the gap 10 is in a state where its surroundings are blocked by liquid leakage, and as shown in FIG. The phenomenon that the liquid does not penetrate into the reflection area 8b for many hours, and the thin paper 8 does not become transparent, so that a large amount of liquid cannot be detected. There has occurred.
Therefore, the present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a high-speed liquid ejecting apparatus at 20 ° C. even with a small amount of liquid having a low surface tension of 60 dynes / cm or less. It is another object of the present invention to provide a liquid leakage sensor capable of detecting a liquid leak. In addition, the case where the case rises, tilts, or falls by itself during the installation work of the liquid leakage sensor is quickly detected, and the case where the case rises from the holder or falls after the case installation work is detected. Another object of the present invention is to provide a liquid leak sensor having a simple / reliable structure with an installation abnormality detecting means capable of quickly detecting and alerting the outside.
Further, an object of the present invention is to form a liquid having a low surface tension of 60 dynes / cm or less at 20 ° C. and a liquid having a surface tension of 60 dynes / cm or more at 20 ° C. In both cases, there is also a need to provide a liquid leakage sensor capable of detecting a small amount of liquid at high speed.
[0004]
[Means for Solving the Problems]
The present invention relates to a leak sensor comprising a reflective boundary surface for leak detection that can come into contact with a leak, a light source unit, a light receiving unit, and a control unit coupled thereto.
The surface tension is a low surface tension liquid having a surface tension of 60 dynes / cm or less at 20 ° C. At least one high-speed liquid leakage drawing-in means for directly and directly pulling up and guiding the liquid leakage detection surface from the floor surface to the reflection boundary surface, even in a small amount,
The projection light of the light source unit is irradiated on the reflection boundary surface for detecting liquid leakage, the reflection light from the reflection boundary surface is received by the light receiving unit, and the output is arithmetically processed by the control unit, and the low surface is processed. This is achieved by enabling the presence or absence of tension leakage to be determined quickly.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 2 to 5 corresponding to FIG. 1A show one embodiment of the liquid leakage sensor 20a of the present invention, and the devices with the same numbers perform the same functions, respectively. A liquid having a low surface tension of 60 dynes / cm or less at a surface tension of 20 ° C. is applied to a predetermined gap and a gap having a predetermined cross-sectional shape capable of exhibiting a capillary phenomenon (for example, a gap of 1 mm or less). A parallel gap and / or a wedge-shaped gap that gradually narrows upward with a maximum gap of 1 mm or less), a small amount from the floor to the leak detection position on the reflective boundary surface for leak detection against gravity. Even if the liquid is leaked, at least one light source means and light receiving means described later for directly pulling up and guiding the liquid immediately are housed in a case whose bottom is made of a transparent or translucent material and integrated. Case 12 and the case Which was provided by configuring at the Chakusuru case holder 5,
ABS resin, polyethylene, polyvinyl chloride, polystyrene, polypropylene, polyvinyl alcohol, methacrylic resin, petroleum resin, polyamide, polyvinylidene chloride, polycarbonate, polyacetal, fluorine resin, polyimide, polyetheretherketone, polyphenylene sulfide, polybenzimidazole, poly Thermoplastic resins such as cycloolefins, or phenolic resins, urea resins, unsaturated polyesters, polyurethanes, alkyd resins, melamine resins, thermosetting resins such as epoxy resins, that is, thermoplastic resins or thermosetting resins, etc. Synthetic resin member / plastic member, or raw material such as a mixture of polyamino acid, aliphatic polyester, poly-ε-caprolactone, polyvinyl alcohol, chitosan, starch, cellulose and a general-purpose polymer Solution resin member, or, those selected from the group consisting of combinations,
Further, polyamide, polycarbonate, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, polyether ether ketone, polyphenylene sulfide, polyarylate, polysulfone, polyether sulfone, polyketone sulfide, polyether imide, polyamide imide, polyimide, polytetrafluoride On the bottom 12d of the case 12 made of a transparent material or a translucent material containing at least one of engineering plastic members such as ethylene fluoride, aromatic polyester, polyaminobismaleimide, and triazine resin, or glass or ceramics, 5, the bottom surface 12p is provided with a protruding liquid leakage detecting portion that can be in direct contact with the floor surface 1;
The detection unit is provided with planar liquid-leakage detecting total reflection surfaces 12m and 12n at a predetermined inclination angle of about 35 to 50 degrees with respect to the floor surface 1, and these planar total reflection surfaces 12m and 12n are provided. Is formed so that extensions of the total reflection surface intersect each other at a predetermined angle so as to perform the same function as the corner cube, and at least one light source means, light receiving means, and control means coupled thereto are provided, Each of the reflection boundary surfaces is provided on the same side, and light is projected from the light source means to the first total reflection boundary surface, and reflected light from the first total reflection boundary surface is reflected. In order to project on the second total reflection boundary surface, receive the reflected light from the second total reflection boundary surface by the light receiving means, and calculate the output by the control means to detect the liquid leakage,
First, the projection light 22u from the light source means 14a forming the first optical system for detecting the liquid leakage is totally reflected from the total reflection surface 12m from above to the total reflection surface 12m at a predetermined critical angle or more. Irradiated at a predetermined incident angle according to the refractive index of the transparent or translucent material 12d, the reflected light 22v is projected on the total reflection surface 12n, and the total reflection light 24u from the total reflection surface 12n is At a predetermined light receiving angle corresponding to the refractive index of the translucent material 12d, the light is received by the light receiving means 16 of a photoelectric conversion element such as a CCD or a MOS photodiode, and the leak detection light propagating through the optical path is converted into an electric signal. The output is converted into a digital signal by an A / D converter 32 at a predetermined sampling period, for example, through a multiplexer 31 as shown in FIG. 6, and a microprocessor (MPU) 36 The data is sequentially written to the buffer memory 34 in the control means 30 also serving as the detection means 18 and digitally processed, or the analog output of the light receiving means 16 is directly input to an analog calculation means including an analog comparator (not shown). It is also possible to perform analog processing in the control means 30 which also serves as the detection means 18 constituted by an analog circuit. It is preferable that the light source unit 14a, the light receiving unit 16, the detecting unit 18, the control unit 30, and the like be integrally formed and fixed on the circuit board 7 also serving as a light shielding material.
Next, a second optical system is provided independently of the first optical system as the installation abnormality detecting means 70 for checking the parallelism of the case 12 with respect to the floor surface 1. The projection light from the light source means 14c is projected toward the thin paper 8, and a projection 5h is formed on the inner peripheral portion of the ring-shaped frame 5a having a hollow portion of the holder 5 toward the center of the inner ring. A mounting plane 5j formed of a light absorbing material / light transmitting material is formed on the upper surface of the projection 5h, and a part of the thin paper 8 is mounted on the flat surface 5j. The thin paper 8 as the optical (reflective) reflecting surface of No. 3 is irradiated with light 22z at an incident angle smaller than the critical angle of the case bottom 12d, and the reflected light 24z is received by the light receiving means 16c. It is converted into an electric signal and input to the control means 30 It has become the jar. It is preferable to fill / form a light shielding material 12q for the projection light directly incident on the light receiving means 16c from the light source means 14c between the light source means 14c and the light receiving means 16c. In order to optically separate the optical system from the optical system, it is preferable to fill / form the light shielding material 12q between them.
Further, the control means 30 can be operated as a means for judging the presence / absence of liquid leakage and a means for judging the installation abnormality of the case. Also, the installation abnormality detection for checking the parallelism of the case 12 to the floor surface 1 is possible. The means 70 is an optical installation abnormality detection means in the above example, but other than this, an installation abnormality detection means utilizing a change in a magnet or capacitance can also be used.
It is also possible to attach a light shielding material such as a metal foil to the inside of the case bottom 12d, and the light shielding material excludes the light irradiation surface of the case bottom and the reflected light receiving surface near the light receiving means. When disposed in the range, there is an optical effect of blocking unnecessary reflected light from the floor surface and preventing reception of the reflected light even when the floor surface is white or a mirror surface when the liquid leaks. Further, the detection output of the liquid leakage processed by the control means 30 is output to the outside as an electric signal via the cable 26, and the display means 29 provided on the upper surface of the case 12 also has a green / red switchable LED. For example, a warning is displayed. It is preferable to use the holder 5 whose outer diameter is at least 1.3 times the outer diameter of the case 12 from the viewpoint of preventing the sensor 20a from overturning. When the case 12 is installed alone, the case 12 easily falls down. Therefore, usually, the holder 5 in which the case 12 is inserted is firmly fixed to the floor surface 1 with a fixing material such as a screw, and / or a building, a desk, or the like. An arm-shaped press-contact means 60 for fixing the case 12 from the side wall or side surface 61 is extended from the case upper cover (FIG. 2C), and one end 62 thereof is fixed to the building 61 by a fixing material 64 such as a screw or a nail. And the other end 66 may be pressed against the upper part of the case to prevent the case 12 from falling over.
The distance d4 between the case bottom 12d and the floor surface 1 can be changed to various ones in accordance with the viscosity / surface tension of the liquid to be detected. , 12n and the floor 1 are likely to cause an erroneous operation, so that the holder 5 and the case 12 can be attached and detached one-touch as described later, and the distance d4 is reduced with respect to external vibration. It is preferable that the structure does not change. Further, when the holder 5 is made of a light shielding material, there is an effect of preventing noise light from entering around the case 12 and receiving unnecessary reflected light from the floor surface. When the case 12 is used alone as the liquid leakage sensor 20a without using the holder 5, the floor d is provided by a separately installed pressure contact means 60 or the like so that the above-described distance d4 does not change even with external vibration. Preferably, it is fixed to the surface 1. It is preferable that the light source unit 14c, the light receiving unit 16c, the display unit 29, and the like are also integrally formed and fixed to the circuit board 7 which also functions as a light shielding material.
[0006]
Next, the irradiation position of the liquid leakage detection projection light 22u on the total reflection surface 12m is preferably a position below and close to the floor surface 1, such as a convex liquid leakage detection unit bottom surface 12p provided at the bottom of the case 12. Can be used as an adhesive sheet holder for thin paper 8 in which a cutting line 8d as shown in FIG. Further, it is preferable to fill / form between the light source means 14a and the light receiving means 16 with a light shielding material 12q of the projected light which is directly incident on the light receiving means 16 from the light source means 14a.
Thus, the entire case 12 is fitted and fixed to the holder 5 (FIGS. 4A and 4B) mainly comprising the ring-shaped frame 5a having the central hollow portion by insertion / attachment. (FIG. 2), and a bottom surface 5b (FIG. 4 (B)) of the frame 5a facing the floor surface 1 has a predetermined gap d5 from the floor surface 1 (usually a gap of 2 mm to 5 mm). A liquid leakage detecting portion is formed in the bottom 12d of the case 12 so as to protrude from the bottom 12d of the case 12 so that the bottom surface 12p is in close contact with the floor surface 1 with the thin paper 8 interposed therebetween. Since it is provided ((FIGS. 2B and 5)), it is possible to directly detect the low surface tension liquid leak 2a diffused in a thin film form on the floor surface 1 from the floor surface 1 diffused in the central hollow portion. On the other hand, the holder 5 is provided with a single or a plurality Utilizing through holes 5d formed in a plurality of projections 5c, the floor 1 may be fixed to the floor surface 1 with a fixing material such as a nail / screw, or an adhesive may be applied to the fan-shaped bottom surface of the projections 5c. It may be adhered and fixed in close contact with the floor surface 1 (FIG. 4), or may be simply mounted movably on the floor surface 1 without fixing. An arm-shaped press-contact means 60 for fixing the case 12 from the side surface 61 is extended to the case upper lid, and one end 64 thereof is fixed to the building 61 side by the fixing member 62, and the other end 66 is press-contacted to the upper part of the case, The case 12 may be prevented from falling (FIG. 2C).
Further, in the example of FIG. 2, the light source means 14a, 14c and the light receiving means 16, 16c are housed in a case whose bottom 12d is made of a transparent material or a translucent material, and the bottom of the case 12, And the case holder 5 for mounting the liquid container, constitutes the high-speed liquid leakage drawing means 6. The structure (FIG. 5) is, for example, provided on the inner peripheral portion of the frame 5 a toward the center of the inner ring. A rectangular projection 5e having a wedge-shaped distal end 5f is formed integrally with the frame 5a, and the projection 5e is preferably formed of an absorber / translucent material for the projected light for detecting liquid leakage. The bottom surface 5g of 5e does not adhere to the floor surface 1 and has a predetermined gap d6 = 1 mm or less (preferably 0.9 mm or less, more preferably 0.5 mm or less) between the floor surface 1 and the parallel space. Forming a part d6, at 20 ° C., at 60 dynes / cm or less. The liquid 2a having a low surface tension is rapidly diffused to the bottom surface 5g facing the floor surface 1 by utilizing the capillary action of the parallel gap d6, and a protrusion is formed at one end of the bottom surface 5g. The front end 5f of 5e has a parallel gap d7 with a predetermined gap d7 of 1 mm or less (preferably 0.9 mm or less, more preferably 0.5 mm or less) between the total reflection surface 12m of the case 12 and the front end 5f. And / or forming a wedge-shaped gap d7 that gradually narrows upward with a maximum gap d7 of the lower end portion of 1 mm or less (preferably 0.9 mm or less, more preferably 0.5 mm or less), Utilizing such a capillary phenomenon of the gap d7, the liquid 2a having a low surface tension of 60 dynes / cm or less at a temperature of 20 ° C. is subjected to a predetermined liquid leakage at the reflection boundary surface 12m for liquid leakage detection against the gravity. Small amount from floor 1 to above detection position Also, so that the direct quickly lead pulling up.
In addition, it is also possible to insert a part of the thin paper for liquid detection 8 having a cut piece 8d into the gap d7, and the speed at which the low surface tension liquid 2a is detected is determined by experiments. The detection speed was almost the same regardless of whether or not was interposed in the gap d7. Further, the entire case 12 is fitted by inserting / attaching to fitting engagement portions 5n provided upright at a plurality of locations on the inner peripheral portion of the upper surface of the ring-shaped frame 5a so as to be rotatably fixed. (FIGS. 2A and 2B), a tapered surface is formed diagonally upward at the tip 5p of the locking portion 5n, and a structure in which the attachment / detachment operation of the case 12 can be performed with one touch is preferable. (FIG. 4 (B)).
[0007]
The operation of the liquid leakage sensor 20a in such a configuration will be described with reference to FIGS. 3 (C) and 5. First, when the case 12 is not firmly fixed to the floor 1 by the holder 5 or the pressing means 60, FIG. In this case, the case 12 and the holder 5 are in an abnormal installation state in which the case 12 and the holder 5 are floated, tilted or fallen, so that the optical path 22z / 24z of the projection light / reflected light of the optical installation abnormality detecting means 70 is normal. The projection light 22z of the light source means 14c cannot be formed at the position, and is transmitted / diffused from the optical boundary surface 12a of the main body 12d to a gas layer such as air, and does not reach the reflection member (thin paper 8), or The reflected light 24z is projected at an angle of more than a predetermined angle, and the reflected light 24z hardly reaches the light receiving means 16c. , The installation abnormality of the liquid leakage sensor 20a is easily detected, and an installation abnormality alarm signal (or error code ER-A) is output to the outside via the cable 26 via the control means 30 including MPU or the like. The power supply to the light source means 14a, 14c and the light receiving means 16, 16c is stopped by a power control unit (not shown), and the liquid leakage sensor 20a enters an error standby state.
In a normal state in which such an alarm signal is not output, power is supplied from the power supply control unit to the light source units 14a and 14c and the light receiving units 16 and 16c, the liquid leakage sensor 20a is activated, and if there is no liquid leakage, As shown in FIG. 3C, the optical path 22z / 24z of the projection light / reflected light of the optical installation abnormality detection means 70 is formed at a normal position, and the projection light 22z from the light source The reflected light 24z is reflected by the reflecting surface of the reflecting material (thin paper 8) placed on 5j, and the reflected light 24z is input to the light receiving element 16c. Then, the normal installation state of the liquid leakage sensor 20a is detected. Further, the projection light 22u from the light source means 14a forming the liquid leakage detecting optical system is totally reflected from the upper side to the lower side of the first total reflection surface 12m at a predetermined critical angle or more by the total reflection surface 12m. Irradiated at a predetermined incident angle according to the refractive index of the transparent or translucent material 12d, the total reflection light 22v is projected on the second total reflection surface 12n, and the total reflection light 24u from the total reflection surface 12n is The light leak detecting light received by the light receiving means 16 at a predetermined light receiving angle corresponding to the refractive index of the transparent material or the translucent material 12d, and transmitted through the optical path is converted into an electric signal by a photoelectric conversion element, and its output is In the control unit 30 also serving as the detection unit 18, the digital output or the analog output of the light receiving unit 16 is directly input to the analog operation unit including an analog comparator and the like. Double In the control unit 30 within, it is analog processing. In the case where there is no liquid leakage, in the above example, the normal light receiving amount is detected by any of the light receiving means, and the phenomenon of a decrease in the light receiving amount does not occur.
[0008]
Next, when the liquid 2a having a low surface tension of not more than 60 dynes / cm at 20 ° C. is diffused into the floor surface 1 in a thin film form, the rectangular body forming a part of the high-speed liquid leakage drawing means 6 is formed. When the leaked liquid 2a at the liquid level d1 has spread to the area of the floor surface 1 facing the bottom surface 5g of the protrusion 5e, the gap is formed by the parallel gap d6 formed between the floor surface 1 and the bottom surface 5g. If the distance between the part d6 and the liquid level d1 of the leaked liquid 2a is set to substantially the same length, or the liquid level d1> the distance d6, the capillary phenomenon of the void part d6 is reduced. Utilizing this, the leaked liquid 2a is rapidly drawn into the parallel gap d6 (2a1 in FIG. 5), and the leaked liquid 2a comes into contact with the bottom surface 5g and is rapidly diffused throughout the bottom surface 5g facing the floor surface 1. You.
Thereafter, when the leaked liquid 2a is diffused at one end of the bottom surface 5g to the lowermost end forming one end of the tip 5f of the protrusion 5e (2a2 in FIG. 5), the leaked liquid 2a is further reflected on the total reflection surface of the case 12. It reaches one end of the parallel gap d7 formed by the 12m and the tip 5f, and the gap d7 is set so that the capillary phenomenon of the leak 2a appears in the predetermined gap d7. Even if the amount of leakage is small, it is directly lifted and guided directly from the floor surface 1 to a position above a predetermined leakage detection position on the liquid-reflection detecting reflection boundary surface 12m against the gravity (see FIG. 5). 2a3). Thus, when the liquid leak 2a passes above the predetermined liquid leak detection position on the liquid leak detecting reflection boundary surface 12m, most of the light 22u projected from the light source means 14a is totally reflected by the total reflection surface 12m. Instead, the bottom portion 12d and the total reflection surface 12m move substantially straight, and furthermore, the leaked liquid 2a filled in the gap d7 refracts and goes straight, and then the rectangular projection 5e formed of the absorber / transparent material of the projection light. In addition, it travels substantially straight in the liquid leak 2a filled in the gap d6, is reflected by the floor surface 1, and propagates and proceeds in the direction opposite to the total reflection surface 12n.
Therefore, the light 24u totally reflected by the total reflection surface 12m forming a part of the liquid leakage detection optical path and then also totally reflected by the total reflection surface 12n is greatly reduced in the amount of light received by the light receiving means 16. Then, the output is subjected to arithmetic processing by the control means 30 so that a very small amount of the leaked liquid 2a can be detected at a very high speed in a very early stage when it has begun to spread thinly on the floor surface 1. If a large amount of the low surface tension leaked liquid 2a leaks to the floor surface 1 at a time, the entire outer periphery of the case 12 will be flooded with the leaked liquid 2a, and the leak detecting reflection boundary surface 12n Is also submerged in the liquid leakage 2a, so that the projection light 22u from the light source 14a is totally reflected by the total reflection surface 12m, and the total reflection light 22v is projected on the total reflection surface 12n. Also, the liquid does not totally reflect on the total reflection surface 12n due to the liquid leak 2a, and immediately proceeds substantially straight on the total reflection surface 12n, and further refracts straight through the liquid leak 2a filled in the gap d4. The light is reflected at 1 and propagates and proceeds in a direction completely unrelated to the installation position of the light receiving means 16. Therefore, the amount of light 24u totally reflected by the total reflection surface 12n forming a part of the liquid leakage detection optical path and received by the light receiving means 16 is greatly reduced, and the output is calculated by the control means 30. It is possible to detect the occurrence of a large amount of the leaked liquid 2a at a very early stage at a very high speed.
Thus, when the control unit 30 also serving as the liquid leakage detecting unit 18 detects the liquid leakage 2a and / or 2, the display unit 29 is turned on in red and the presence or absence of the liquid leakage is output to the outside via the cable 26. (Liquid leak detection error code ER-B).
[0009]
Next, when the leaked liquid 2 (as shown in FIG. 1 (E)) having a surface tension of 60 dynes / cm or more at 20 ° C. spreads on the floor surface 1, the leaked liquid 2 at the liquid level d3 is formed. Since the thin paper 8 is interposed in the parallel gap d4 formed between the floor surface 1 and the case bottom 12d, the leaked liquid 2 comes into contact with the outer peripheral portion or a part of the thin paper 8 (FIG. 5) Immediately after, the leaked liquid 2 permeates / diffuses over the entire surface of the thin paper 8, and the leaked liquid 2 is rapidly drawn through the thin paper 8 to near the total reflection surface 12 n. Thus, when the liquid leakage 2 reaches a predetermined liquid leakage detection position on the liquid leakage detecting reflection boundary surface 12n, the projection light 22u from the light source means 14a is totally reflected by the total reflection surface 12m, and the total reflection light 22v However, on the total reflection surface 12n, the liquid does not undergo total reflection due to the liquid leakage 2 and travels substantially straight through the total reflection surface 12n and further refraction straight through the thin paper 8 into which the liquid leakage 2 has penetrated. The light is reflected and propagates and travels in a direction completely unrelated to the installation position of the light receiving means 16. Therefore, the amount of light 24u totally reflected by the total reflection surface 12n forming a part of the liquid leakage detection optical path and received by the light receiving means 16 is greatly reduced, and the output is calculated by the control means 30. At a very early stage of the process, the leaked liquid 2 begins to diffuse thinly on the floor surface 1 and can be detected very quickly.
When a large amount of the liquid 2 is generated at one time, the entire outer periphery of the case 12 is immersed in the liquid 2 and the predetermined liquid detection position on the liquid-reflection detecting boundary surface 12n is also in the liquid 2. The projection light 22u from the light source 14a is totally reflected by the total reflection surface 12m, and even if the total reflection light 22v is projected on the total reflection surface 12n, the total reflection surface 12n Does not undergo total reflection, immediately proceeds substantially straight on the total reflection surface 12n, further refracts straight through the leaked liquid 2 filled in the gap d4, is reflected on the floor surface 1, and is positioned at the position of the light receiving means 16 Propagation / progression in a completely unrelated direction. Therefore, the amount of light 24u totally reflected by the total reflection surface 12n forming a part of the liquid leakage detection optical path and received by the light receiving means 16 is greatly reduced, and the output is calculated by the control means 30. By processing, it is possible to detect a large amount of the leaked liquid 2 at a very early stage at a very high speed.
Thus, when the control unit 30 also serving as the liquid leakage detecting unit 18 detects the liquid leakage 2a or 2, the display unit 29 is turned on in red and the presence or absence of the liquid leakage is output to the outside via the cable 26 ( Liquid leakage detection error code ER-B). In the above-described light receiving process, the sensitivity of the light receiving units (elements) 16 and 16c can be improved by collecting the reflected light widely by the light collecting unit such as a lens or a concave mirror.
Furthermore, in the liquid leakage sensor 20a, since the thin paper 8 is interposed between the case 12 and the holder 5, the leaked liquid 2 diffused to the floor 1 sequentially penetrates the thin paper 8, and the thin paper 8 When the liquid 2 penetrates and diffuses to the mounting plane 5j formed on the upper surface of the projection 5h provided on the inner peripheral side of the ring-shaped frame 5a while converting the Light 22z emitted from the case bottom 12d does not reflect on the thin paper 8 which is the target (reflection) boundary surface, but goes straight through the thin paper 8 in which the liquid leaks, without being reflected on the surface of the thin paper 8. A straight line at a predetermined refraction angle into the mounting plane 5j formed of the absorbing material / light transmitting material, the amount of the reflected light 24z received by the light receiving means 16c is greatly reduced, and the case is abnormally installed. The control means 30 as the detection means 70 is activated, and a case installation error To, leakage 2 can be detected. Therefore, even if the first optical system for detecting liquid leakage fails and does not operate normally, the liquid leakage 2 can be detected as a case installation error, and the error detection function of the sensor can be further improved. it can.
[0010]
Thus, the liquid leak sensor 20a of FIGS. 2B and 5 is sandwiched between the gas layers d6 and d7 or the liquid leak permeable layer (for example, in FIG. 5, between the floor surface 1 and the bottom surface 12p). (A part of the thin paper 8), at least one reflecting boundary surface 12m, 12n for detecting the liquid leakage, which can come into contact with the liquid leakage, the light source means 14a, the light receiving means 16, and the control means 30 coupled thereto. A part or the whole of the surface facing the floor surface 1 of the gas layer d6 or the liquid leakage permeable layer (d4 or the thin paper 8 sandwiched between the floor surface 1 and the bottom surface 12p). Open directly to the floor 1 (in the example of FIG. 5, the gas layer d6 is the entire floor side), or configure the floor as a part of the gas layer or the liquid leakage permeable layer (for example, in FIG. 5, Part of the thin paper 8 sandwiched between the floor surface 1 and the bottom surface 12p). In addition, the leaked liquid 2a having a low surface tension of 60 dynes / cm or less is applied to a predetermined gap d0 and a gap having a predetermined cross-sectional shape capable of exhibiting a capillary phenomenon to prevent the liquid from leaking. It is provided with at least one high-speed liquid-leakage pull-in means 6 for directly and quickly raising a small amount even from the floor surface 1 to the reflection boundary surface 12m, and projecting light 22u of the light source means 14a to detect the liquid-reflection reflection boundary surface 12m. And the reflected light from the reflective boundary surface 12m is received by the light receiving means 16 and the output is subjected to arithmetic processing by the control means 30 so that the presence or absence of the low surface tension liquid 2a can be quickly determined. It can be called a liquid sensor.
In addition, the leak sensor 20a shown in FIGS. 2B and 5 includes at least two leak-detection total reflection boundary surfaces 12m and 12n that can come into contact with the leak, and the gas layers d6 and d7 or the leak-penetrating layer ( For example, in FIG. 5, a part of the thin paper 8 sandwiched between the floor surface 1 and the bottom surface 12p) is interposed, and at least one of the light source unit 14a, the light receiving unit 16, and the control unit 30 coupled thereto are provided. Are arranged on the same side with respect to each of the reflection boundary surfaces, and the light 22u is projected from the light source means 14a to the first total reflection boundary surface 12m, and the light is reflected from the first total reflection boundary surface 12m. The reflected light 22v is projected onto the second total reflection boundary surface 12n, the reflected light 24u from the second total reflection boundary surface 12n is received by the light receiving means 16, and the output is arithmetically processed by the control means 30 to perform liquid leakage. Is a type of liquid leak sensor that detects A part or the whole of the surface of the layers d6, d7 or the liquid leakage permeable layer facing the floor 1 is directly opened to the floor 1 or the floor 1 is formed as a gas layer or a part of the liquid leakage permeable layer. Further, the leaked liquid 2a having a low surface tension of 60 dynes / cm or less at a surface tension of 20 ° C. at 20 ° C. is formed by using a predetermined gap d0 and a void portion capable of exhibiting a capillary action with a predetermined cross-sectional shape. At least one high-speed liquid suction means 6 for directly and quickly pulling up a small amount of liquid from the floor 1 to the reflection boundary surface 12m for detecting liquid leakage against the gravitational force is provided. It can be said that the liquid sensor is a liquid leakage sensor that can determine the presence or absence of the liquid 2a quickly even with a small amount of leakage.
In addition, as the predetermined gap d0 of the void portion where the above-mentioned capillary phenomenon can be exhibited, a small amount of the liquid 2a having a low surface tension is dropped on the floor surface 1 as shown in FIG. Is preferably equal to or less than the thickness d1 (d0 <d1), and a length capable of stably expressing the capillary phenomenon of the leaked liquid 2a. As the predetermined cross-sectional shape of the gap that can be stably expressed, for example, a cross section of a parallel gap below a gap d0 and / or a cross section of a wedge-shaped gap gradually narrowing upward below a maximum gap d0 are used. Any shape can be used as long as it is possible and has a cross-sectional shape capable of stably exhibiting the capillary phenomenon.
[0011]
Next, FIG. 6 corresponding to FIG. 2 and FIG. 5 shows another embodiment of the liquid leakage sensor 20b of the present invention, and the devices having the same numbers perform the same functions. At the same time, the high-speed liquid leakage drawing means 6b is constituted only by the case 12 side, and no electric wiring is provided in the liquid leakage detecting section, thereby realizing an explosion-proof structure in which an electric ignition / ignition accident never occurs, and the holder 5 is provided. It is not necessary and is configured to be operable as a single sensor case. The first light transmission means 40a, 40c such as an optical fiber is used to separate the light source means 14 separately provided in the control unit 39 at a remote place. A first optical system for transmitting the projection lights 22x and 22z, respectively, and projecting and receiving light on the reflection boundary surfaces 12m and 12n by the light transmission means 40a and 42a is formed. The first optical system is described later by the light transmission means 40c and 42c. High The light on the reflection mounting surface 5j formed on the upper surface of the liquid leakage drawing means 6b (in this example, since the surface 5j does not use the thin paper 8, it is preferable to use a light reflecting material (white or mirror surface)). Since the second optical system (optical path of the optical installation abnormality detecting means 70b) for transmitting and receiving light is formed, even if the liquid 2 / 2a for detecting liquid leakage is volatile and there is a danger of ignition or explosion, This makes it possible to detect liquid leakage very safely.
That is, in the above-mentioned first optical system, a part of the irradiation light from the light source means 14 provided at a remote place is guided into the case 12 by the light transmission means 40a, and the critical angle such that total reflection occurs. At the above-mentioned predetermined angle, the reflection boundary surface 12m at the bottom of the case is irradiated as projection light 22u, is totally reflected by the reflection boundary surface 12n, and the reflected light 24u is received by the optical transmission means 42a and provided at a remote place. The received light is transmitted to the light receiving element 16 and input to the control means 30 which also serves as the detection means via the multiplexer 31, the AD conversion means 32, and the double buffer 34. In the above-mentioned second optical system, another part of the irradiation light from the light source means 14 provided at a remote place is guided into the case 12 by the light transmission means 40c, and is within the critical angle or more than the critical angle. At a predetermined angle, the reflection member 5j is irradiated as the projection light 22z, and the reflection light 24z is received by the optical transmission means 42c, transmitted to the light receiving element 16c provided at a remote place, and provided with the multiplexer 31, the AD conversion means 32 , Via the double buffer 34 to the control means 30 also serving as the detection means. Furthermore, the bottom of the case 12 is formed using a transparent light member 12d made of a transparent material or a translucent material as a base material, and the outside thereof is made of a light-shielding synthetic resin or the like except for a light irradiation surface and a reflection surface / light reception surface. It is preferable to cover or constitute with a light-shielding material and to be integrally molded with the transmitted light member 12d. If such a light-shielding member is used, it is hardly affected by ambient noise light even without the holder 5, and the floor surface when leaking liquid enters. An optical structure that does not receive unnecessary reflected light from the floor surface even in a white or mirror surface can be realized.
Further, in the example of FIG. 6, the high-speed liquid suction means 6b is configured only on the case 12 side, and the configuration is, for example, between the case bottom 12d and the floor 1 in the center direction of the case 12. , A rectangular projection 12u whose tip 12v is wedge-shaped is made of a transparent or translucent material with respect to the case bottom 12d, and is bent into the main body 12d and the high-speed liquid leakage drawing means 6b. / It is made of a synthetic resin material which is integrally molded and can be divided. It is preferable that the projection 12u is formed of an absorbent / translucent material for the projection light for liquid leakage detection, and the bottom surface 12w of the projection 12u does not adhere to the floor surface 1, A parallel gap d6 having a predetermined gap d6 of 1 mm or less (preferably 0.9 mm or less, more preferably 0.5 mm or less) is formed, and a low-surface-tension liquid leak of 60 dynes / cm or less at 20 ° C. 2a is rapidly diffused to the bottom surface 12w facing the floor surface 1 by utilizing the capillary action of the parallel gap d6, and the tip 12v of the protrusion 12u at one end of the bottom surface 12w A parallel gap d7 having a predetermined gap d7 of 1 mm or less (preferably 0.9 mm or less, more preferably 0.5 mm or less) between the total reflection surface 12m of the case 12 and / or , The maximum gap d7 at the lower end is 1 mm or less ( Preferably, 0.9 mm or less, more preferably 0.5 mm or less) to form a wedge-shaped gap d7 gradually narrowing upwards, and at 20 ° C. by utilizing the capillary phenomenon of the gap d7, A small amount of liquid 2a having a low surface tension of 60 dynes / cm or less can be quickly and directly with a small amount from the floor surface 1 to a position above a predetermined liquid leakage detecting position of the liquid leakage detecting reflection boundary surface 12m against gravity. It is designed to lead up to.
As such a synthetic resin member for integral molding, a general thermoplastic resin or thermoplastic elastomer can be used. Examples of the thermoplastic resin include polyethylene terephthalate, amorphous polyethylene terephthalate, and polyethylene. , Polystyrene, polypropylene and the like can be used, and polybutadiene resin can be used as the thermoplastic elastomer for integral molding.
Specifically, the case bottom is formed integrally with the main body 12d and the high-speed liquid leaking means 6b connected by a hinge, and the main body 12d and the high-speed liquid leaking means 6b are V-shaped at the outer peripheral edge. The grooves are connected to each other, and are integrally formed of a synthetic resin material, that is, a thermoplastic resin or a thermoplastic elastomer. When the sheet is bent toward the total reflection surface 12m through the V-shaped groove, the surface becomes A gap d7 is formed through a plurality of small projections having a predetermined height d7 formed on the tip end side of 12v, and a predetermined height d6 formed on the surface 12w side of the high-speed liquid leakage drawing means 6b. A gap d6 is formed with the floor surface 1 when bent, via a plurality of small projections, and constitutes an opening / closing mechanism for generating a repulsive force. Therefore, when the main body 12d of the case and the high-speed liquid leakage drawing means 6b are bent toward the total reflection surface 12m side and are closed in a substantially horizontal state with respect to the installation surface of the case 12, their own weights or pressure contact means from outside are required. 60 allows the main body portion 12d and the high-speed liquid leakage drawing means 6b to maintain the state in which the gap d7 is formed, and forms a part of the optical path of the optical installation abnormality detecting means 70b. That is, when the case 12 is installed on the horizontal floor 1, the installation surface of the case 12 is horizontal / parallel to a reference horizontal plane defined by a level or the like.
[0012]
In such a configuration, the operation will be described next. In the high-speed liquid-leakage pull-in means 6 of FIG. 5 and the high-speed liquid-leakage pull-in means 6b of FIG. They are completely the same except that they are not used and light transmission / reception means for light transmission / reception are respectively added to a part of the optical path. The same is true.
Specifically, first, in the optical installation abnormality detection means 70b, the projection light 22z from the light source means 14-the light transmission means 40c is applied to the reflection material 5j provided on the upper surface of the high-speed liquid suction means 6b by a critical angle. The reflected light 24z is received by the light transmitting means 42c and the light receiving means 16c, converted into an electric signal, and input to the control means 30. The reflecting surface based on the reflecting material 5j having a white or mirror-like shape can be provided on the upper surface of the projection 12u, and is formed by bonding, melting, and press-fitting the projection 12u. An uneven reflecting surface may be engraved on the upper surface of 12u to form a reflecting surface for the projected light 22z.
On the other hand, when the main body 12d and the protrusion 12u of the case 12 do not form the gap d7 at a predetermined interval, the main body 12d and the protrusion 12u are formed by the repulsive force generated by the hinge mechanism. An opening / closing mechanism that can maintain a state in which the main body 12d and the projection 12u are opened at a distance d7 or more is biased to the case 12 in advance. Therefore, in the abnormal installation state, the normal second optical path is not formed, and the projection light is diffused into the gas layer such as air, and the optical path 22z / of the projection light and the reflected light of the above-described optical installation abnormality detecting means 70b. 24z cannot be formed at a normal position, the installation abnormality of the case 12 is easily detected, and the installation abnormality alarm signal (or the error code ER-A) is sent to the cable 2 via the control means 30 including MPU or the like. The output to the outside, leakage sensor 20b is in error standby state.
In a normal state in which such an alarm signal is not output, the liquid leak sensor 20b is in an operating state, and when there is no liquid leak, as shown in FIG. The optical path 22z / 24z of the reflected light is formed at a normal position, the projection light 22z from the light source means 14-the light transmission means 40c is reflected by the reflection surface 5j of the projection 12u, and the reflected light 24z is transmitted by the light transmission means. The transmitted state is transmitted via the means 42c, input to the light receiving element 16c, and the output thereof is compared with the normal reflected light level by the detecting means 18, whereby the normal installation state of the liquid leakage sensor 20b is easily detected.
Also, the projection light 22u from the light source means 14-the light transmission means 40a forming the liquid leakage detecting optical system is totally downwardly directed from the top to the first total reflection surface 12m at a predetermined critical angle at the total reflection surface 12m. Irradiation is performed at a predetermined incident angle according to the refractive index of the transparent or translucent material 12d so that the light is reflected, and the totally reflected light 22v is projected on the second total reflection surface 12n, and the total reflection light 22v The reflected light 24u is received at one end of the light transmitting means 42a at a predetermined light receiving angle corresponding to the refractive index of the transparent or translucent material 12d, and transmitted to the light receiving means 16 via the light transmitting means 42a. The leak detection light propagating through the path is converted into an electric signal by the photoelectric conversion element 16, and its output is digitally processed in the control means 30 also serving as the detection means 18, or the analog output of the light receiving means 16 is directly converted , Analog comparator, etc. Is input to the al made an analog calculation means, in the control means 30 which also serves as a detection unit 18 which is an analog circuit, is analog processing. In the case where there is no liquid leakage, in the above example, the normal light receiving amount is detected by any of the light receiving means, and the phenomenon of a decrease in the light receiving amount does not occur.
[0013]
Next, when the liquid 2a having a low surface tension of 60 dynes / cm or less at 20 ° C. is diffused in a thin film form on the floor surface 1, the rectangular body forming a part of the high-speed liquid leakage drawing means 6b is formed. When the leaked liquid 2a at the liquid level d1 has spread to the area of the floor surface 1 facing the bottom surface 12w of the projection 12u, the gap is formed by the parallel gap d6 formed between the floor surface 1 and the bottom surface 12w. If the distance between the part d6 and the liquid level d1 of the leaked liquid 2a is set to substantially the same length, or the liquid level d1> the distance d6, the capillary phenomenon of the void part d6 is reduced. Utilizing this, the leaked liquid 2a is rapidly drawn into the parallel gap d6 (2a1 in FIG. 5), and the leaked liquid 2a comes into contact with the bottom surface 12w and is rapidly diffused throughout the bottom surface 12w facing the floor surface 1. You.
Thereafter, when the leaked liquid 2a is diffused at one end of the bottom surface 12w to the lowermost end forming one end of the tip end 12v of the protrusion 12u (2a2 in FIG. 5), the leaked liquid 2a is further diffused into the total reflection surface of the case 12. The gap d7 reaches one end of the parallel gap d7 formed by the front end 12v and the front end 12v. The gap d7 is set so that the capillary action of the leaked liquid 2a occurs in the predetermined gap d7. Even if the amount of leakage is small, it is directly lifted and guided directly from the floor surface 1 to a position above a predetermined leakage detection position on the liquid-reflection detecting reflection boundary surface 12m against the gravity (see FIG. 5). 2a3). Thus, when the liquid leak 2a passes above the predetermined liquid leak detection position on the liquid leak detecting reflection boundary surface 12m, most of the light 22u projected from the light source means 14 is totally reflected by the total reflection surface 12m. Instead, after substantially going straight through the bottom portion 12d and the total reflection surface 12m, and further going straight through refraction of the leaked liquid 2a filled in the gap d7, a rectangular projection 12u formed of an absorbing material / translucent material of the projected light is formed. In addition, it travels substantially straight in the liquid leak 2a filled in the gap d6, is reflected by the floor surface 1, and propagates and proceeds in the direction opposite to the total reflection surface 12n. Accordingly, the light 24u totally reflected by the total reflection surface 12m forming a part of the liquid leakage detection optical path and then also totally reflected by the total reflection surface 12n is received at one end of the light transmission means 42a, The amount of received light transmitted to the light receiving means 16 via the light receiving means 42a is greatly reduced, and its output is arithmetically processed by the control means 30 so that a small amount of the liquid leak 2a starts to diffuse thinly on the floor surface 1. In the early stage, detection can be performed very quickly.
If a large amount of the low surface tension leaked liquid 2a leaks to the floor surface 1 at a time, the entire outer periphery of the case 12 will be flooded with the leaked liquid 2a, and the leak detecting reflection boundary surface 12n Is also submerged in the liquid leakage 2a, the projection light 22u from the light source means 14 is totally reflected by the total reflection surface 12m, and the total reflection light 22v is projected on the total reflection surface 12n. Also, the liquid does not totally reflect on the total reflection surface 12n due to the liquid leak 2a, and immediately proceeds substantially straight on the total reflection surface 12n, and further refracts straight through the liquid leak 2a filled in the gap d4. 1 and propagates and travels in a direction completely unrelated to the installation position of the optical transmission means 42a. Therefore, the amount of light 24u totally reflected by the total reflection surface 12n forming a part of the liquid leakage detection optical path and received at one end of the light transmission unit 42a is greatly reduced, and the light transmission unit 42a The light receiving output transmitted to the light receiving means 16 via the control means 30 is arithmetically processed by the control means 30, so that a large amount of the liquid leakage 2a can be detected at a very early stage at a very high speed.
Thus, when the control unit 30 also serving as the liquid leakage detecting unit 18 detects the liquid leakage 2a and / or 2, the display unit 29 is turned on in red and the presence or absence of the liquid leakage is output to the outside via the cable 26. (Liquid leak detection error code ER-B).
[0014]
Next, in the case of FIG. 6, when the liquid 2 (as shown in FIG. 1E) having a surface tension of 60 dynes / cm or more at 20 ° C. diffuses into the floor surface 1, Even if the leaked liquid 2 of d3 is diffused in the parallel gap d4 formed between the floor 1 and the case bottom 12d, since the thin paper 8 is not inserted, the floor 1 is directly reflected on the total reflection surface. It diffuses in the direction of 12n. Thus, when the liquid leakage 2 reaches a predetermined liquid leakage detection position on the liquid leakage detection reflection boundary surface 12n, the projection light 22u from the light source means 14-light transmission means 40a is totally reflected by the total reflection surface 12m, On the total reflection surface 12n, the total reflection light 22v does not totally reflect due to the liquid leakage 2 but travels substantially straight through the total reflection surface 12n, further refraction straight through the liquid leakage 2 and then on the floor surface 1. The light is reflected and propagates and travels in a direction completely unrelated to a predetermined position where one end of the optical transmission means 42a is installed. Therefore, the amount of light 24u totally reflected by the total reflection surface 12n forming a part of the liquid leakage detection optical path and received at one end of the light transmission unit 42a is greatly reduced, and the light transmission unit 42a The output of the light receiving unit 16 transmitted via the control unit 30 is subjected to arithmetic processing by the control unit 30 to detect the liquid 2 very quickly at a very early stage when the liquid 2 has begun to spread thinly on the floor surface 1.
When a large amount of the liquid 2 is generated at one time, the entire outer periphery of the case 12 is immersed in the liquid 2 and the predetermined liquid detection position on the liquid-reflection detecting boundary surface 12n is also in the liquid 2. The projection light 22u from the light source means 14-the light transmission means 40a is totally reflected by the total reflection surface 12m, and even if the total reflection light 22v is projected on the total reflection surface 12n, the liquid 2 leaks. The light does not undergo total reflection on the total reflection surface 12n but immediately travels substantially straight on the total reflection surface 12n, further refraction goes straight through the leaked liquid 2 filled in the gap d4, and is reflected on the floor surface 1 to transmit light. It propagates and travels in a direction completely unrelated to the position where one end of the means 42a is installed. Accordingly, the amount of light 24u totally reflected by the total reflection surface 12n forming a part of the liquid leakage detection optical path and received by the light receiving means 16 via the light transmission means 42a is significantly reduced, and The output is arithmetically processed by the control means 30, so that a large amount of the leaked liquid 2 can be detected at a very early stage at a very high speed.
Thus, when the control means 30 also serving as the liquid leakage detecting means 18 detects the liquid leakage 2a or 2, the presence / absence of the liquid leakage is output to the outside via the cable 26 (liquid leakage detection error code ER-B). . In the above-described light receiving process, the sensitivity of the light receiving units (elements) 16 and 16c can be improved by collecting the reflected light widely by the light collecting unit such as a lens or a concave mirror.
[0015]
Therefore, according to the liquid leakage sensor 20b having the structure as shown in FIG. 6, the liquid leakage sensor 20b is merely placed on the floor surface 1 and is hardly affected by extraneous light even without the holders 4, 5 and the thin paper 8. In addition, there is an advantage that a leak can be quickly detected in the initial stage of leaking out of a small amount to the floor 1 before the leaks 2a and 2 reach the upper surface of the holder 4. In addition, since no electric signal flows to the liquid leakage detection part, the detection processing can be performed extremely safely even for volatile liquid leakage. The leak is checked by double or triple detection, and the reliability of the leak detection process can be further improved. In addition, by changing the length of the optical transmission means 40/42, the light source means 14 and The physical distance between the light receiving means 16, 16c and the like and the reflection boundary surface 12m / 12n and the like can be changed to a desired variable distance.
In addition, in a state where the predetermined distances d6 and d7 cannot be maintained between the main body 12d and the protrusion 12u of the case, the optical path of the optical installation abnormality detecting means 70b is not formed at a predetermined position and is generated from the hinge mechanism. Due to the repulsive force, the main body 12d and the projection 12u float, tilt, or fall into an abnormal installation state, and the opening and closing mechanism that can maintain the state where the main body 12d and the projection 12u are open allows projection. Since the light reflection path is greatly bent, the abnormal installation state can be easily detected, and the liquid leakage error and the abnormal installation error can be separately detected, transmitted, and handled.
Note that the thin paper 8 can be used also in the liquid leakage sensor 20b in FIG. 6 as in FIG.
[0016]
Next, FIG. 7A corresponding to FIG. 2, FIG. 5 and FIG. 6 shows another embodiment of the liquid leakage sensor 20c of the present invention, in which the same reference numerals are assigned. The apparatus performs the same function, and optically divides the lower part of the bottom of the case 12 of FIG. 5 into a case body and a holder 50, and constitutes the high-speed liquid leakage drawing means 6c only on the holder 50 side. ,
The structure is such that a rectangular projection 5e having a wedge-shaped tip 5f is formed integrally with the frame 5a on the inner peripheral portion of the frame 5a toward the center of the inner ring. It is preferable that the projection 5e is formed of an absorbing material / translucent material for the liquid detection projection light, and the bottom surface 5g of the projection 5e does not adhere to the floor surface 1 and a predetermined gap d6 = 1 mm or less between the floor surface 1 and the floor surface 1. A parallel gap d6 (preferably 0.9 mm or less, more preferably 0.5 mm or less) is formed, and a low surface tension liquid leak 2a of 60 dynes / cm or less at 20 ° C. is applied to the parallel gap d6. At the bottom 5g facing the floor surface 1 at a high speed by utilizing the capillary phenomenon, and the tip 5f of the projection 5e at one end of the bottom surface 5g is connected to the total reflection surface of the holder 50. 5s, a predetermined gap d7 = 1 mm or less (preferably 0.9 mm or less) More preferably, a parallel gap d7 of 0.5 mm or less is formed, and / or the maximum gap d7 at the lower end is 1 mm or less (preferably 0.9 mm or less, more preferably 0.5 mm or less). A wedge-shaped gap d7 gradually narrowing upward is formed, and by utilizing the capillary phenomenon of the gap d7, the liquid 2a having a low surface tension of 60 dynes / cm or less at 20 ° C. is resistant to gravity. Thus, even if the amount is small, it is immediately and directly pulled up from the floor surface 1 to a position above the predetermined liquid leakage detection position on the liquid leakage detection reflection boundary surface 5s. In addition, it is also possible to insert a part of the liquid detecting thin paper 8 having the cut piece 8d into the gap d7.
The optical system for detecting liquid leakage is provided below the bottom 12d of the case 12 made of a transparent member or a translucent member, and is provided with a holder 50 that can be optically divided with the bottom 12d, and is integrally formed, The holder 50 is provided with planar total reflection surfaces 5 s and 5 t at a predetermined inclination angle, and these planar total reflection surfaces 5 s and 5 t are so arranged that the tips thereof perform the same function as a corner cube. The extensions are formed so as to intersect with each other, and the projection light 22u from the light source means 14a is applied to the total reflection surface 5s from substantially vertically downward, and the reflection light 22v is projected to the total reflection surface 5t to perform total reflection. The reflected light 24u of the surface 5t is received by the light receiving means 16 and converted into an electric signal.
In such a configuration, the operation of the high-speed liquid dropping means 6c of the liquid leak sensor 20c is exactly the same as the operation of the high-speed liquid dropping means 6 in FIG.
[0017]
Next, FIGS. 7 (B) to 7 (D) corresponding to FIGS. 4 (A), 4 (B) and 7 (A) show another embodiment of the high-speed liquid leakage drawing means 6d of the present invention. The devices having the same reference numerals perform the same function, and constitute the high-speed liquid leakage drawing means 6d only on the holder 4j side. Toward the inner center, a Y-shaped arm 4m is formed integrally with the frame 4k, and the arm 4m has a dish-shaped shell 8k made of a transparent material, and a gap with the floor 1 at a predetermined distance d6. An outer peripheral extension 8m is formed so as to form a part d6. Further, along the outer circumference of the arm 4m, at a distance d8 via a predetermined number of minute projections, the cap part 8n is horizontally positioned on the upper surface, / Formed in a translucent material, in the region of the liquid leakage detection reflection surface 8p on the inner upper surface of the shell 8k, A diffused surface of color is formed, and a gap d8 in which the liquid 2a having a low surface tension can be diffused by capillary action is formed at a portion where the arm 4m and the shell 8k are opposed to each other. The liquid leak 2a can be drawn directly from the surface 1 to the irregular reflection surface 8p, and a water-stopping material 4q is attached or fixed to each edge of the surface of the arm 4m facing the floor surface 1 to form a gap. The liquid 2a is prevented from diffusing / permeating into the part d2.
Therefore, when the leaked liquid 2a does not exist in the reflection area 8p, the projection light 22u is irregularly reflected on the reflection surface 8p, and the white reflected light 24u can be detected by the light receiving means 16, but the leaked liquid 2a is caused by the capillary phenomenon. When raised from the floor surface 1 to the reflection area 8p via the gaps d6 and d8, the irregular reflection surface 8p becomes transparent due to the liquid leakage 2a, so that the projection light 22u passes through the shell 8k and the arm 4m. And the amount of reflected light 24u from the reflecting surface 8p is drastically reduced, and the amount of light received by the light receiving means 16 is drastically reduced. Thus, liquid leakage can be detected. The same effect as the high-speed liquid leakage drawing means 6 can be expected with the high-speed liquid leakage drawing means 6d having such a configuration.
[0018]
【The invention's effect】
As described above, according to the liquid leakage sensors 20a and 20b of the present invention, the capillarity including the floor surface 1 as a component of the void can be exhibited in the sensor case and / or the holder facing the floor surface. The provision of the high-speed liquid leakage drawing means 6, 6b, 6c, etc. provides a very early stage in which a small amount of liquid having a low surface tension diffuses in a thin film form on the floor surface 1 against the gravity. The liquid can be directly lifted and guided directly from the floor surface to the liquid leakage detection position on the liquid leakage detecting reflection boundary surface, without having to wait until the time required for the liquid leakage 2a to rise to the water level over the holder upper surface 4a. Even if a very small amount of leaked liquid 2a can be detected due to capillary action, even if it is not possible to secure a sufficient amount of leaked liquid so that the leaked liquid 2a can get over the holder upper surface 4a. The advantage is that it can detect liquid leakage at high speed. .
Also, according to the liquid leakage sensor 20a of the present invention, the liquid leakage 2a having a low surface tension of 60 dynes / cm or less at 20 ° C. began to diffuse into the floor surface 1 in a small amount and in a very thin film. In the step, the small amount of the leaked liquid 2a is removed by the high-speed leak drawing means 6 by using the capillary phenomenon against a predetermined leak detecting position on the leak detecting reflection boundary surface 12m against the gravity. Up to the conventional holder upper surface 4a, the liquid level of the leaked liquid 2a rises, and furthermore, during a period when a large amount of leaked liquid flows out to a predetermined leak detection height. In addition, the leak detection operation of the leak sensor does not go into any pause state, and the leak 2a can be detected at a very high speed at the initial stage when a small amount of leak occurs on the floor surface. . In addition, even when a large amount of the low surface tension leaked liquid 2a leaks to the floor surface 1 at a time, the entire outer periphery of the case 12 is submerged in the leaked liquid 2a. 2a, the total reflection phenomenon of the liquid for leak detection does not occur on the total reflection surface 12n due to the liquid leakage 2a, and the received light amount of the total reflection light 24u on the total reflection surface 12n is greatly reduced immediately. Then, the output is arithmetically processed by the control means 30, and the occurrence of a large amount of the liquid leakage 2a can be instantaneously detected without being affected by the retention of bubbles or the like.
Next, at a very early stage when the leaked liquid 2 having a surface tension of 60 dynes / cm or more at 20 ° C. began to spread to the floor surface 1, the leaked liquid 2 was applied to the outer peripheral portion and / or a part of the thin paper 8. Immediately after contact, the leaked liquid 2 is rapidly drawn through the thin paper 8 to the vicinity of the total reflection surface 12n, and when the leaked liquid 2 reaches a predetermined leak detection position on the leak detecting reflection boundary surface 12n, On the total reflection surface 12n, almost no total reflection light is generated due to the liquid leakage 2 that has permeated the thin paper 8, and the projection light for liquid leakage detection travels straight from the total reflection surface 12n into the liquid leakage, so that the light receiving means The amount of received light at 16 greatly decreases, and its output is arithmetically processed by the control means 30. At a very early stage when the leaked liquid 2 begins to diffuse a small amount to the floor 1, a very high speed. It is possible to detect. Also, even if a large amount of the leaked liquid 2 leaks to the floor surface 1 at a time, the entire outer periphery of the case 12 is submerged in the leaked liquid 2, so that the total reflection surface 12 n is instantly submerged in the leaked liquid 2. However, the total reflection of the liquid for detecting liquid leakage does not occur on the total reflection surface 12n due to the liquid leakage 2, and the amount of the total reflection light 24u received on the total reflection surface 12n immediately decreases greatly, and the output is reduced. A large amount of the leaked liquid 2 can be instantaneously detected without being affected by the retention of bubbles at all by the arithmetic processing by the control means 30.
When the case 12 is not firmly fixed to the holder 5 or the like, the main body 12d of the case 12 and the thin paper 8 on the mounting surface 5j of the holder 5 do not adhere to each other, and the main body 12d and the thin paper 8 However, the installation abnormal state where the optical installation abnormality detecting means 70 floats, tilts or tilts, and the optical path of the projection light / reflected light of the optical installation abnormality detection means 70 cannot be formed at a normal position, and the projection light 22z of the light source means 14c Is projected at a predetermined angle or more by the thin paper 8, and the reflected light 24z hardly reaches the light receiving means 16c. Therefore, the output of the light receiving means 16c is compared with the normal reflected light level by the detecting means 18. This makes it possible to easily detect an abnormal installation of the liquid leakage sensor 20a. Therefore, the power supply to the light source means 14a, 14b, which consumes more than half of the power consumption of the sensor 20a, can be cut immediately, so that the energy saving of the liquid leakage sensor can be achieved, and the liquid leakage can not be distinguished conventionally. Since the abnormal error and the sensor installation abnormal error can be clearly distinguished, the plant monitoring center or the like can appropriately cope with each error situation after receiving the error occurrence signal. The installation abnormality detecting means 70 can operate normally and stably even when the liquid to be detected is a strong acid such as sulfuric acid, hydrochloric acid, or nitric acid, or a strong alkaline solution such as possible soda or possible potassium. A mechanism and a structure are preferable, and since the bottom of the case is made of a transparent material or a translucent material, the liquid leakage sensor 20a can realize a structure in which no electronic components or the like are exposed to the outside, and have excellent chemical resistance. At the same time, the height of the case 12 and the holder 5 from the floor surface is constant, but the case 12 and the holder 5 can be fixed rotatably, so that the attachment and detachment operation is very easy. Further, a safe liquid leak sensor having an explosion-proof structure can be easily provided.
[Brief description of the drawings]
FIG. 1A is a diagram showing a structure of a conventional optical liquid leak sensor using thin paper.
FIG. 1B is a diagram for explaining the principle that bubbles stay at the center of thin paper in a conventional liquid leakage sensor.
FIG. 1C is a view for explaining the liquid level d1 of the liquid leakage 2a having a low surface tension.
FIG. 1D is a diagram illustrating a process in which the liquid leakage 2a diffuses into the gap d2 between the holder 4 and the floor surface 1.
FIG. 1E is a diagram for explaining the liquid level d3 of the liquid leak 2 having a relatively high surface tension.
FIG. 2A is a plan view showing a structure of a liquid leakage sensor 20a of the present invention.
FIG. 2B is a cross-sectional view of 2B-2B.
FIG. 2C is a side view thereof.
FIG. 3A is a longitudinal sectional view taken along 3A-3A.
FIG. 3B is an enlarged view of FIG.
FIG. 3C is a cross-sectional view taken along line 3C-3C.
FIG. 4A is a plan view of a holder 5 of the present invention.
FIG. 4B is a central cross-sectional view thereof.
FIG. 4C is a plan view of the thin paper 8 having the cut portion 8d.
FIG. 5 is an enlarged cross-sectional view showing the operation principle of the high-speed liquid leakage drawing means 6 of the present invention.
FIG. 6 is a diagram showing an example of an explosion-proof liquid leakage sensor 20b of the present invention.
FIG. 7 (A) is a diagram showing an example of another high-speed liquid leakage drawing means 6c of the present invention.
FIG. 7B is a plan view showing an example of another high-speed liquid leakage drawing means 6d according to the present invention.
FIG. 7C is a cross-sectional view at the center thereof.
FIG. 7D is a cross-sectional view illustrating the operation principle of the high-speed liquid leakage drawing means 6d.
[Explanation of symbols]
1 floor
2 Leakage
4, 40b, 5, 50 holder
4a Holder bottom
6, 6b to 6d High-speed liquid leakage drawing means
12m, 12n, 5s, 5t Optical interface
8 Thin paper
10, d4 to d8 gap
12 cases
12d transmitted light member, semi-transmitted light member
14, 14b light source means
16, 16c light receiving means
20a-20d Leak sensor
22u, 22z projection light
24u, 24z reflected light
30 control means
40a, 40c, 42a, 42c Optical transmission means
70 Installation abnormality detection means
