JP3756683B2

JP3756683B2 - Leak sensor

Info

Publication number: JP3756683B2
Application number: JP35300398A
Authority: JP
Inventors: 建一林田
Original assignee: Tsuden KK
Current assignee: Tsuden KK
Priority date: 1998-12-11
Filing date: 1998-12-11
Publication date: 2006-03-15
Anticipated expiration: 2018-12-11
Also published as: JP2000180294A

Description

【０００１】
【発明の属する技術分野】
この発明は、水、酸性溶液、アルカリ溶液等の電気的導通を有する液体や、アルコール、シンナー、ベンジン等の有機性等の絶縁性を有する液体の漏液を確実に検知する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はかかる従来の反射方式の漏液センサ２０の原理を示す図であり、床面１に薄紙及びケースのホルダ４がその底面４ａを黒色に塗装され反射板を兼ねてネジ等の止め具６により固定され、その上に白色の薄紙（又は布、合成樹脂等でも良い）８が水平に載置されている。また、ホルダ４にはその底部１２ａが透明又は半透明な部材で構成されたケース１２が挿入され、ケース１２の内部には光源手段１４、受光手段１６及びコンパレータ等を含む検知手段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、ケースの底部１２ａと薄紙８との間には空隙部１０が設けられている。この空隙はほこり、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以内が望ましい。また反射板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。更にまた、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や赤外レーザー発光素子、光ファイバー等の光源手段１４から光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。
【０００３】
【発明が解決しようとする課題】
しかしながら上述した従来の光学式漏液センサに当初予期できなかった次のような問題点が発生した。（Ａ）床面１にホルダ底面４ａが水平であり、ケース底部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とケース底部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、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。
（Ｂ）しかるにホルダ底面４ａが水平で平らなホルダ４は現在大量に使用中であるので、床面１に固定されたホルダ４を一つ一つ交換する作業は膨大な時間がかかり、ほとんど不可能である。
（Ｃ）また、薄紙８も消耗品であり、漏液検知毎に廃棄しているが、できれば従来の薄紙８もそのまま使用できる機会があるとよい。
よってこの発明は上述のような事情に鑑みて成されたものであり、この発明の目的は一度に大量の漏液が発生した場合にも気泡等の影響を受けることなく安定かつ確実に漏液を検出することの可能な漏液センサ及び漏液センサ用薄紙並びに漏液センサ用ホルダを提供することにある。
また、この発明の目的は、揮発性で引火性の爆発の危険のある液体に対しても、防爆に注意しつつ、かかる液体が一度に大量に発生しても、気泡等の影響を受けることなく遠隔地で安全かつ確実に漏液を検出することの可能な漏液センサ及び漏液センサ用薄紙並びに漏液センサ用ホルダを提供することにある。
【０００４】
【課題を解決するための手段】
この発明は、漏液の吸収により透明状態になる白色の薄紙と、この薄紙を水平に載置し保持すると共に底面が反射板を形成する薄紙ホルダと、このホルダに挿入され底部が透明板又は半透明板で構成されたケースと、この透明板又は半透明板を介して前記薄紙に光を照射する光源手段と、前記ホルダ底面からの反射光を受光する受光手段と、この受光手段からの情報データに基づいて漏液を検知する検知手段とから漏液センサを構成し、前記光源手段及び受光手段を一体化して前記ケース内に納め、前記薄紙の一端に漏液が接触した場合、漏液が速やかに浸透し得るように前記ホルダとケースとの間に空隙部を設けるようにした漏液センサに関し、この発明の上記目的は、前記薄紙の形状が円又は非円の形状の場合、前記受光手段の検知する薄紙の反射領域に気泡が停留しないように、前記薄紙の外縁部及び反射領域を除いた中間部に、前記反射領域に対し非対称な位置・形状で穴部を設け、漏液が一度に大量に溢れた場合にも前記薄紙の反射領域には気泡が残らないようにすることによって達成される。
【０００５】
【発明の実施の形態】
以下、図面に基づいて、この発明の好適な実施例に付いて詳細に説明する。図２（Ａ）はこの発明の反射式漏液センサ及び透過式漏液センサの両方で使用することが可能な漏液センサ用薄紙８であり、この例では円形状の薄紙８の外縁部８ｃ及び反射領域８ｂを除いた中間部に、反射領域８ｂに対し非対称な位置・形状で穴部８０を設けている。かかる薄紙を従来の薄紙と交換し、ホルダ４、ケース１２等は従来のものをそのまま使用すると（図２（Ｂ））、図２（Ｃ）に示すように、外縁部９ａ、９ｂに漏液が一部接触した場合には、中間に穴部８０が設けられたので、ルート９ａ〜９ｅ又は９ｂ〜９ｃを順次浸透して漏液が反射領域８ｂに到達し、従来より少し検出時間がかかるが反射領域８ｂが白色から透明色に変化するので、図１と同様の原理により反射光量２４の変化量を検知して漏液を検出することができる。また、図２（Ｃ）の外縁部９ｃ、９ｄ、９ｅに漏液の一部が接触した場合には従来とほぼ同一の検出時間で漏液を検出することができる。
しかして一度に大量の漏液２が床面１に溢れた場合には、従来は薄紙８に穴部がないので、外縁部からほぼ同一の浸透速度で漏液が浸透すると共に、薄紙等に吸収されていた気体が中央の反射領域に浸透圧により圧縮されながら集められ、気体の圧力と浸透する漏液の圧力とが釣り合った時点で気泡７が形成され、この気泡が反射領域８ｂに停留して漏液検出ができなかった。一方、図２（Ａ）のように穴部８０を設けた薄紙８では外縁部から中央の反射領域８ｂまで漏液が浸透していくのに必要な時間が異なるので、薄紙等に吸収されていた気体は順次穴部８０に押し出され気泡７となり、確実に反射領域８ｂに漏液２を浸透させることができる。従って、反射領域８ｂが白色から透明色に変化し（図２（Ａ））、ホルダ４の黒色の底面４ｂにより照射光２２が吸収され、漏液２の検知ができることが実験により確認できた。尚、この現象は水以外にも塩酸や硫酸等の非常に粘性の高い液体に対しても有効であることが実験により確認できた。従って、既設の光学式漏液センサに対しては薄紙８を図２（Ａ）のような形状に変更したものに交換するだけで、一度に大量に発生する漏液の検出も確実に行なうことができるようになる。
【０００６】
次に、図２に対応させて示す図３はこの発明の別の一実施例であり、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３（Ａ）に示すように穴部のない従来の薄紙８を使用し続ける場合には、例えば、図３（Ｂ）に示すようにホルダ４の底面４ａの反射領域を含む個所に凸部４ｂ〜４ｅを設け、図３（Ｃ）に示すようにこの上に薄紙８を水平に載置し、ケース１２の底部１２ａで挟着すると、薄紙８とホルダ底面４ａとの相対距離を不均一にでき、特に、凸部４ｂ〜４ｅと薄紙８との空隙は他の底面より狭くすることができる。かかる構成において、漏液２が薄紙８の外縁部の一部に接触すると、従来と同様に順次薄紙８の中を漏液２が浸透していき、中央の反射領域８ｂに到る。しかして、反射領域８ｂにはホルダ４の底面の凸部４ｂが接近して設けられているので、毛細管現象により凸部４ｂの周辺には速やかに漏液が浸透するようになっている。その結果、薄紙８ｂが白色から透明色に変化するので、反射光２４が大幅に減少し、その変化を受光手段１６及び検知手段１８で検出して外部に出力するようになっている。
また、漏液２が一度に大量に床面１に溢れた場合には、薄紙８の外縁部から中心部に向ってほぼ同一の浸透速度で漏液２が浸透していく。この浸透に伴って薄紙等に吸収されていた気体も中心部に向って移動していくが、図１（Ａ）と異なり、図３（Ｃ）のようにホルダ底面４ａには凸部４ｂが設けられているので、凸部４ｂの内側はその外側より液体の浸透圧が非常に高い状態に設定されている。従って、気泡７の大きさよりも十分に広い面積で凸部４ｂを設けておけば、漏液２は確実に凸部４ｂの外周部に到達することが可能となり、ひとたび漏液２が凸部４ｂの外周に浸透すると、凸部４ｂとケース底部１２ａとで挟着された薄紙８の部分には周囲より高い浸透圧が発生し、この浸透圧により反射領域８ｂに圧縮されつつあった気泡は直ちに図３（Ｃ）の気泡７ａや７ｂとなって凸部４ｂの外側に押し出される。この結果、反射領域８ｂの色は白色から透明色に変化し、上述と同様にして反射光２４の減少が検知され、外部に出力される。
又、図１及び図３に対応させて示す図４は、この発明のまた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、漏液検知部には電気配線をなくし、光ファイバー等の光伝送手段４４、４６により薄紙８への光の投受光を行なうようにしたため、液体２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反射光による漏液検知ができるようにしたもので、遠隔地に設けられた光源１４からの光は光伝送手段４４によりケース１２の底部１２ａまで導かれ光伝送手段４６を介して遠隔地に設けられた受光手段１６まで伝送され、その出力情報が検知手段１８で演算処理されて漏液の有無が判定されるようになっている。更に図４（Ａ）の例ではケース１２の底部１２ａの外側に反射領域８ｂに対応した領域を含んで凸部１２ｂや、１２ｃ〜１２ｅを設け、薄紙８とケース底部１２ａとの相対距離を不均一とし、穴部のない従来の薄紙８も使用できるような構造になっている。また、ホルダ４の底面４ａは図１（Ａ）に示すように平面でも良いし、図４（Ｂ）に示すように凸部４ｂ〜４ｄが設けられていても良い。そして、図４（Ａ）に示すようなケース１２を使用した場合にも、反射領域８ｂに対応した凸部１２ｂの面積を気泡７の面積よりも十分大きく配設しておけば、図３（Ｃ）と同様の原理により漏液２が薄紙８を介して確実に凸部１２ｂまで浸透することが可能となり、凸部１２ｂの内側はその外側よりも十分空隙部１０の間隔が狭く、液体の浸透圧が高くなるので、薄紙８の反射領域８ｂに含まれていた気体は全て凸部１２ｂの外側に押し出され、反射領域８ｂに気泡が停留することを防止することができる。
【０００７】
図１に対応して示す図５はこの発明のまた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（Ａ）ではケース底部１２ａを２段の円錐状に削り、薄紙８の反射領域８ｂに挟着し水平面との傾斜がゆるやかな円錐頂部１２ｇと、空隙部１０内で発生した気泡を全てケース外部へ排出する円錐ガイド面１２ｈとから構成し、反射領域８ｂに対応した領域を含む円錐頂部１２ｇに気泡が停留しないようにしたものである。また、図５（Ｂ）はケース底部１２ａの反射領域８ｂを含む領域を円錐等の凸部１２ｊに加工すると共に、ケース１２の外周部から凸部１２ｊに向け気泡ガイドの溝１２ｋを穿設したもので、かかる構造のケース１２を用いると、円錐頂部１２ｇや凸部１２ｊでは一度に大量の漏水が溢れた場合、漏水２が薄紙８へ浸透していく圧力が他の場所よりも高まるので、反射領域８ｂに吸収されていた気体は全て円錐頂部１２ｇや凸部１２ｊの外へ排出され、大量の漏水も確実に検出することができる。
さらにまた、図１に対応して示す図６はこの発明のまた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６では薄紙８に透明又は半透明の部材として、例えば、両面テープ３０を貼付け、この状態でホルダ４の底面に貼着するようになっている。但し、接着剤等の液状の部材３０を使用すると、溶液に薄紙８が反応して透明となってしまうので、挟着する部材３０は固体形状が望ましい。かかる構成においても薄紙８の反射領域８ｂはその外側と比較すると部材３０が積層され空隙部が狭くなるので、漏液が溢れた場合この部分の浸透圧は薄紙８の他の領域よりも相対的に高くなり、気泡が反射領域８ｂの外側７ａや７ｂに押し出され、安定的に漏液が検出できることが実験により確認できた。
【０００８】
次に、図１及び図４に対応して示す図７及び図８はこの発明のまた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、両図ではそれぞれ薄紙８の透過光を検知して漏液を検出するようになっており図７では受光手段１６又は光源手段１４を床面１の内部に埋設し、透明板４２をその上に載置してホルダ４を構成し、更にその上に薄紙８を載置すると共に、ケース１２と床面に埋設された受光手段１６又は光源手段１４をコネクタ４０で接続するようになっている。また、図８では漏液検知部に電気配線をなくし、光ファイバー等の光伝送手段４４，４６により薄紙８への光の投受光を行なうようにしたもので、液体２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透過光による漏液検知ができるようになっており、遠隔地に設けられた光源１４からの光は光伝送手段４４によりケース１２の底部１２ａまで導かれ、薄紙８に光２２として投射され、その透過光がレンズ４８で収束された後、光伝送手段５０、光コネクタ５２及び光伝送手段４６を介して遠隔地に設けられた受光手段１６まで伝送され、その出力情報が検知手段１８で演算処理されて漏液の有無が判定されるようになっている。かかる構成の透過式漏液センサ２０ａ、２０ｂにおいても、従来は薄紙８をホルダ底面４ａに水平に載置すると共に、その上から光源手段１４又は受光手段１６等を内蔵したケース１２をホルダ４に挿入する構造となっていたので、ケース底部１２ａの薄紙８側はほぼ床面に平行な水平状態に設定され、図１（Ａ）の反射式漏液センサ２０と同様に一度に大量の漏液が床面１に溢れた場合、薄紙８の中央部８ｂに気泡が発生し、薄紙８ｂが透明色に変化せず何時間経過しても大量の漏液が検出できないという問題点が発生していた。しかしながら、図２（Ａ）のように薄紙８に穴部８０を設け、漏液２が薄紙８の透過領域８ｂに外周部からほぼ等しい浸透速度で集中して集まらないように浸透速度に時間差を設けることにより、従来透過領域８ｂに停留していた気泡７を穴部８０に漏液の発生する浸透圧で誘導し、透過領域８ｂを透明色に変化させることができることを本願発明者は発見した。また、上述の気泡７は図４（Ａ）に示すようなケース底部に設けた凸部１２ｂによっても透過領域８ｂの外側に移動させることができることが分った。
更にまた、図５（Ａ）、（Ｂ）に示すようにケース底部１２ａに気泡７を逃すための溝１２ｈ、１２ｋを設けても気泡７の透過領域８ｂへの停留を防止できることが分った。尚、図２（Ａ）乃至図５（Ｃ）に示す技術は複数の技術を組合わせて使用しても何ら問題のないことが分った。
【０００９】
【発明の効果】
以上説明したように、この発明の光学式漏液センサによれば、漏液センサに使用する薄紙８を図２（Ａ）のように穴部を設けた形状に変更したものに交換するだけで、従来の漏液検出能力は何ら低下させることなく、従来の漏液センサ用ホルダやケースをそのまま使用し続けることができると共に、一度に大量の漏液等が発生するというような当初想定しない大事故の場合や、引火かつ揮発性で爆発の危険のある液体に対しても、確実に漏液検出処理を実行することができる。また、ホルダ４やケース１２の交換や新設が可能な場合には、図３乃至図５に示す構造のホルダやケースを使用することにより、従来の穴部のない薄紙も使用し続けることができる。更に、図２（Ａ）のような薄紙と図３乃至図５に示す構造のホルダ及びケースを組合わせて使用すると、漏液検出が一番必要な大量の漏液流出事故といった現象が、正確かつ迅速に実行でき、大変有効である。
【図面の簡単な説明】
【図１】従来の光学式漏液センサの構造を示す図である。
【図２】この発明の漏液センサ用薄紙の構造および動作原理を示す図である。
【図３】この発明の漏液センサ用ホルダの構造の一例を示す図である。
【図４】この発明の防爆型反射式漏液センサ用ケースの構造の一例を示す図である。
【図５】この発明の漏液センサ用ケースの別の一例を示す図である。
【図６】この発明の又別の一例を示す図である。
【図７】この発明の透過式漏液センサの一例を示す図である。
【図８】この発明の防爆型透過式漏液センサの一例を示す図である。
【符号の説明】
１床面
２、２ａ、２ｂ漏液
４ホルダ
７気泡
８薄紙
１０空隙部
１２ケース
１４光源手段
１６受光手段
１８検知手段
４０コネクタ
４４、４６光伝送手段
８０穴部[0001]
BACKGROUND OF THE INVENTION
The present invention provides an improved liquid leakage sensor that reliably detects leakage of electrically conductive liquids such as water, acidic solutions, and alkaline solutions, and organic insulating liquids such as alcohol, thinner, and benzine. About.
[0002]
[Prior art]
Conventional equipment such as factories supplies liquids by piping. However, since pipes are provided with connecting joints at many locations, liquid often leaks from the joints. Therefore, depending on the type of liquid, humans had to constantly monitor for leakage. As such a conventional leakage monitoring method, a conductive method and a liquid amount method are known. Also, Japanese Patent Publication No. 4-70572 discloses that a filter that becomes transparent when liquid leakage is absorbed is irradiated with light from a light source, and when there is liquid leakage, the amount of change in transmitted or reflected light from the filter is detected. Thus, there is described a liquid leakage sensor technique that can reliably detect a liquid leakage.
FIG. 1 is a diagram showing the principle of such a conventional reflection type liquid leakage sensor 20, in which a thin paper and case holder 4 is painted black on the floor surface 1 and its bottom surface 4 a is painted black, and a stopper such as a screw serving as a reflector. 6, and white thin paper (or cloth, synthetic resin, or the like) 8 is horizontally placed thereon. In addition, a case 12 having a bottom 12a made of a transparent or translucent member is inserted into the holder 4, and a detection means 18 including a light source means 14, a light receiving means 16 and a comparator is integrated inside the case 12. And is connected to the outside via a cable 26.
Although the case 12 also serves as a dustproof and waterproof lid, the bottom of the case is used to make it easy for the leaked liquid 2 to penetrate into the reflection area 8b at the center of the thin paper 8, and to shorten the leak detection time. A gap 10 is provided between 12 a and the thin paper 8. This gap is preferably within a few millimeters in order to avoid dirt such as dust and dust and to detect reflected light from the thin paper 8 stably without detecting external noise light. Further, it has been found that the thin paper 8 can be easily replaced and installed by making the reflector 4a and the case 12 a detachable filter. Furthermore, since the location of the leakage is generally not specified, it is possible to respond quickly to leakage that has penetrated from any direction. It was.
In such a configuration, light 22 is normally emitted from light source means 14 such as an LED, an infrared laser light emitting element, or an optical fiber, and white reflected light 24 from thin paper 8 is always detected by light receiving means 16. Thus, when the liquid leak 2 occurs on the floor surface 1, the liquid leak 2 sequentially permeates the reflection area 8b of the thin paper 8 from the contact portion 9, and the contact portion 9 of the thin paper 8 starts from white due to the penetration of the liquid leak. It changes to a transparent color. However, since the reflection 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 16 is absorbed by the reflection plate 4a and greatly reflected. The change in the amount of reflected light is detected by the detection means 18 to detect leakage.
[0003]
[Problems to be solved by the invention]
However, the conventional optical leak sensor described above has the following problems that were not anticipated at the beginning. (A) When the bottom surface 4a of the holder is horizontal on the floor surface 1 and the case bottom 12a is installed in a substantially horizontal state, the high-pressure piping or large-diameter piping is damaged, and a large amount of liquid leakage occurs at once. The lower part of the case 12 is submerged in the liquid leakage almost entirely at the same time. In this state, when the liquid leak 2 starts to permeate from the outer edge portion of the thin paper 8 toward the inside thereof, a part of the gas in the gap 10 between the holder bottom surface 4a and the case bottom portion 12a becomes a bubble. However, the gas in the vicinity of the center of the gap 10 is in a state where the periphery thereof is closed with a liquid leak, as shown in FIG. 1 (B), the bubble is in the center, and Then, the phenomenon stopped at 8b, which was also the reflection area, and the reflection area 8b did not become transparent no matter how many hours later, and a large amount of liquid leakage could not be detected.
(B) However, since the holder bottom 4a with the horizontal and flat holder bottom 4a is currently in use in large quantities, the work of exchanging the holders 4 fixed to the floor 1 one by one takes an enormous amount of time. Is possible.
(C) Further, the thin paper 8 is also a consumable item and is discarded every time the liquid leakage is detected. However, if possible, there should be an opportunity to use the conventional thin paper 8 as it is.
Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to stably and reliably leak liquids without being affected by bubbles or the like even when a large amount of liquid leaks occurs at one time. It is an object of the present invention to provide a leak sensor, a thin paper for leak sensor, and a holder for leak sensor.
In addition, the object of the present invention is to be affected by bubbles and the like even if a large amount of such liquid is generated at a time while paying attention to explosion-proof even for volatile and flammable liquids. It is another object of the present invention to provide a leak sensor, a thin paper for the leak sensor, and a holder for the leak sensor that can detect the leak in a remote place safely and reliably.
[0004]
[Means for Solving the Problems]
The present invention includes a white thin paper that becomes transparent due to absorption of liquid leakage, a thin paper holder in which the thin paper is horizontally placed and held and a bottom surface forms a reflector, and a bottom portion that is inserted into the holder is a transparent plate or A case constituted by a translucent plate, a light source means for irradiating light to the thin paper through the transparent plate or the translucent plate, a light receiving means for receiving reflected light from the bottom of the holder, and a light receiving means from the light receiving means When a leakage sensor is configured from a detection means for detecting leakage based on information data, the light source means and the light receiving means are integrated and housed in the case, and the leakage comes into contact with one end of the thin paper, Regarding the liquid leakage sensor in which a gap is provided between the holder and the case so that the liquid can permeate quickly, the object of the present invention is to form the thin paper in a circular or non-circular shape. Detected by the light receiving means In order to prevent bubbles from staying in the reflection area of the paper, a hole is provided in the middle portion excluding the outer edge and the reflection area of the thin paper at a position / shape asymmetric with respect to the reflection area, so that a large amount of liquid leaks at a time. This is achieved by preventing bubbles from remaining in the reflection area of the thin paper even when it overflows.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2A shows a thin paper 8 for a leak sensor that can be used in both the reflective leak sensor and the transmissive leak sensor of the present invention. In this example, the outer edge 8c of the circular thin paper 8 is shown. In addition, a hole 80 is provided in an intermediate portion excluding the reflection region 8b at a position and shape asymmetric with respect to the reflection region 8b. When such thin paper is replaced with conventional thin paper, and the conventional holder 4 and case 12 are used as they are (FIG. 2 (B)), as shown in FIG. 2 (C), the outer edges 9a and 9b are leaked. Is partially in contact with each other, the hole 80 is provided in the middle, so that the liquid 9L sequentially penetrates the routes 9a to 9e or 9b to 9c, and the leaked liquid reaches the reflection region 8b. However, since the reflection region 8b changes from white to transparent, it is possible to detect leakage by detecting the amount of change in the amount of reflected light 24 based on the same principle as in FIG. Further, when a part of the leaked liquid comes into contact with the outer edge portions 9c, 9d, and 9e in FIG. 2C, the leaked liquid can be detected with substantially the same detection time as the conventional one.
However, when a large amount of liquid leakage 2 overflows on the floor surface 1 at a time, the thin paper 8 conventionally has no hole, so that the liquid permeates from the outer edge portion at substantially the same penetration speed, and into the thin paper or the like. The absorbed gas is collected in the central reflection area while being compressed by osmotic pressure, and bubbles 7 are formed when the gas pressure and the leaked liquid pressure are balanced, and these bubbles stay in the reflection area 8b. As a result, leak detection was not possible. On the other hand, in the thin paper 8 provided with the hole 80 as shown in FIG. 2 (A), the time required for the leakage to penetrate from the outer edge portion to the central reflection region 8b is different. Then, the gas is sequentially pushed out into the hole 80 to become the bubble 7 and the liquid leakage 2 can be surely permeated into the reflection region 8b. Therefore, it was confirmed by experiments that the reflection region 8b changes from white to transparent (FIG. 2A), the irradiation light 22 is absorbed by the black bottom surface 4b of the holder 4, and the leakage 2 can be detected. It has been confirmed by experiments that this phenomenon is effective not only for water but also for highly viscous liquids such as hydrochloric acid and sulfuric acid. Therefore, it is possible to reliably detect a large amount of leaked liquid at once by simply replacing the existing optical leak sensor with a thin paper 8 that has been changed to the shape shown in FIG. Will be able to.
[0006]
Next, FIG. 3 corresponding to FIG. 2 is another embodiment of the present invention, and devices having the same reference numerals perform the same functions and have holes as shown in FIG. 3 (A). When the conventional thin paper 8 having no portion is continuously used, for example, as shown in FIG. 3 (B), convex portions 4b to 4e are provided at locations including the reflection region of the bottom surface 4a of the holder 4, and FIG. ), When the thin paper 8 is horizontally placed thereon and sandwiched between the bottom portions 12a of the case 12, the relative distance between the thin paper 8 and the holder bottom surface 4a can be made uneven, and in particular, the convex portions 4b to 4e. And the thin paper 8 can be narrower than the other bottom surface. In such a configuration, when the leaked liquid 2 comes into contact with a part of the outer edge of the thin paper 8, the leaked liquid 2 sequentially permeates through the thin paper 8 as before, and reaches the central reflection region 8b. Thus, since the convex portion 4b on the bottom surface of the holder 4 is provided close to the reflection region 8b, the liquid leaks quickly into the periphery of the convex portion 4b due to a capillary phenomenon. As a result, since the thin paper 8b changes from white to a transparent color, the reflected light 24 is greatly reduced, and the change is detected by the light receiving means 16 and the detecting means 18 and output to the outside.
Further, when the leaked liquid 2 overflows on the floor surface 1 in a large amount at once, the leaked liquid 2 permeates from the outer edge portion of the thin paper 8 toward the center portion at substantially the same penetration speed. With this permeation, the gas absorbed in the thin paper also moves toward the center, but unlike FIG. 1A, the convex portion 4b is formed on the holder bottom surface 4a as shown in FIG. Since it is provided, the inside of the convex portion 4b is set to a state in which the osmotic pressure of the liquid is much higher than the outside thereof. Therefore, if the convex part 4b is provided in an area sufficiently larger than the size of the bubble 7, the liquid leakage 2 can surely reach the outer peripheral part of the convex part 4b, and once the liquid leakage 2 has reached the convex part 4b. Osmotic pressure is generated in the portion of the thin paper 8 sandwiched between the convex portion 4b and the case bottom portion 12a, and bubbles that are being compressed into the reflection region 8b by this osmotic pressure immediately become. The bubbles 7a and 7b in FIG. 3C are pushed out of the convex portion 4b. As a result, the color of the reflection region 8b changes from white to transparent, and the decrease in the reflected light 24 is detected and output to the outside in the same manner as described above.
FIG. 4 corresponding to FIGS. 1 and 3 shows another embodiment of the present invention, and devices having the same numbers perform the same functions and detect leaks. Since the electrical wiring is eliminated in the part and light is transmitted and received on the thin paper 8 by the optical transmission means 44 and 46 such as an optical fiber, the liquid 2 is volatile and extremely safe even when there is a risk of ignition or explosion. The liquid leakage can be detected by reflected light, and the light from the light source 14 provided at the remote place is guided to the bottom 12a of the case 12 by the light transmission means 44 and provided at the remote place through the light transmission means 46. The output information is transmitted to the light receiving means 16 and the output information is subjected to arithmetic processing by the detecting means 18 to determine the presence or absence of liquid leakage. Further, in the example of FIG. 4A, the convex portion 12b and 12c to 12e are provided outside the bottom portion 12a of the case 12 so as to include the region corresponding to the reflective region 8b, and the relative distance between the thin paper 8 and the case bottom portion 12a is not set. The structure is such that a conventional thin paper 8 that is uniform and has no holes can be used. Further, the bottom surface 4a of the holder 4 may be a flat surface as shown in FIG. 1A, or may be provided with convex portions 4b to 4d as shown in FIG. 4B. Even when the case 12 as shown in FIG. 4A is used, if the area of the convex portion 12b corresponding to the reflective region 8b is sufficiently larger than the area of the bubbles 7, FIG. According to the same principle as in C), the leaked liquid 2 can surely permeate through the thin paper 8 to the convex part 12b, and the gap 12 is sufficiently narrower on the inside of the convex part 12b than on the outer side. Since the osmotic pressure becomes high, all the gas contained in the reflection region 8b of the thin paper 8 is pushed out of the convex portion 12b, and it is possible to prevent bubbles from being retained in the reflection region 8b.
[0007]
FIG. 5 corresponding to FIG. 1 shows another embodiment of the present invention, and devices having the same reference numerals perform the same functions, and in FIG. 5A, the case bottom 12a. And a conical guide surface 12h for discharging all the bubbles generated in the gap 10 to the outside of the case. The bubbles are prevented from staying at the top 12g of the cone including the region corresponding to the reflection region 8b. 5B, the region including the reflection region 8b of the case bottom 12a is processed into a convex portion 12j such as a cone, and a bubble guide groove 12k is formed from the outer periphery of the case 12 toward the convex portion 12j. However, when the case 12 having such a structure is used, when a large amount of water leaks at the top of the cone 12g or the convex portion 12j, the pressure at which the water leak 2 penetrates into the thin paper 8 is higher than other places. All of the gas absorbed in the reflection region 8b is discharged out of the cone top portion 12g and the convex portion 12j, and a large amount of water leakage can be reliably detected.
Further, FIG. 6 shown corresponding to FIG. 1 shows another embodiment of the present invention, and devices having the same reference numerals perform the same functions, and in FIG. As a transparent or translucent member, for example, a double-sided tape 30 is attached, and in this state, it is attached to the bottom surface of the holder 4. However, when a liquid member 30 such as an adhesive is used, the thin paper 8 reacts with the solution and becomes transparent. Therefore, the member 30 to be sandwiched is preferably in a solid shape. Even in such a configuration, the reflection region 8b of the thin paper 8 has the member 30 laminated and the gap becomes narrower than the outside of the reflection region 8b. Therefore, when the liquid leaks, the osmotic pressure of this portion is relative to the other regions of the thin paper 8. It was confirmed by experiments that bubbles were pushed out to the outside 7a and 7b of the reflection region 8b and liquid leakage could be detected stably.
[0008]
Next, FIG. 7 and FIG. 8 shown corresponding to FIG. 1 and FIG. 4 show another embodiment of the present invention, and the devices with the same reference numbers perform the same functions, respectively. In both figures, the light transmitted through the thin paper 8 is detected to detect leakage. In FIG. 7, the light receiving means 16 or the light source means 14 is embedded in the floor surface 1 and the transparent plate 42 is placed thereon. The holder 4 is configured to be mounted, and the thin paper 8 is further mounted thereon, and the case 12 and the light receiving means 16 or the light source means 14 embedded in the floor surface are connected by a connector 40. Further, in FIG. 8, the electric leakage wiring is not provided in the liquid leakage detection portion, and light is transmitted and received on the thin paper 8 by the optical transmission means 44 and 46 such as an optical fiber. The liquid 2 is volatile and ignites and explodes. Even when there is a risk of light leakage, it is possible to detect liquid leakage by transmitted light very safely. Light from the light source 14 provided at a remote place is guided to the bottom 12a of the case 12 by the light transmission means 44, and is thin paper. 8 is projected as light 22, and the transmitted light is converged by the lens 48, and then transmitted to the light receiving means 16 provided at a remote place through the light transmission means 50, the optical connector 52 and the light transmission means 46. The output information is subjected to arithmetic processing by the detection means 18 so as to determine the presence or absence of liquid leakage. Also in the transmission type liquid leakage sensors 20a and 20b having such a configuration, conventionally, the thin paper 8 is horizontally placed on the holder bottom surface 4a, and the case 12 including the light source means 14 or the light receiving means 16 and the like is mounted on the holder 4 from above. Since the structure is inserted, the thin paper 8 side of the case bottom 12a is set in a horizontal state substantially parallel to the floor surface, and a large amount of liquid leakage at a time, similar to the reflective liquid leakage sensor 20 of FIG. Is overflowing the floor 1, bubbles are generated in the central portion 8 b of the thin paper 8, and the thin paper 8 b does not change to a transparent color and a problem that a large amount of liquid leakage cannot be detected after many hours has occurred. It was. However, as shown in FIG. 2 (A), a hole 80 is provided in the thin paper 8, and a time difference is made in the permeation speed so that the leaked liquid 2 does not concentrate in the permeation region 8b of the thin paper 8 from the outer periphery at a substantially equal permeation speed. The inventor of the present application has found that by providing the bubble 7 that has been retained in the transmission region 8b in the past by the osmotic pressure generated by the liquid leakage in the hole 80, the transmission region 8b can be changed to a transparent color. . Further, it has been found that the above-mentioned bubbles 7 can be moved to the outside of the transmission region 8b also by the convex portion 12b provided at the bottom of the case as shown in FIG.
Furthermore, as shown in FIGS. 5 (A) and 5 (B), it has been found that even when grooves 12h and 12k for allowing the bubbles 7 to escape are provided in the case bottom 12a, the bubbles 7 can be prevented from staying in the transmission region 8b. . It has been found that the techniques shown in FIGS. 2A to 5C have no problem even if a plurality of techniques are used in combination.
[0009]
【The invention's effect】
As described above, according to the optical liquid leakage sensor of the present invention, the thin paper 8 used for the liquid leakage sensor is simply replaced with one that has been changed to a shape having a hole as shown in FIG. The conventional leakage sensor holder and case can continue to be used as they are without degrading the conventional leakage detection capability, and a large amount of leakage or the like is not expected at the beginning. The liquid leakage detection process can be reliably executed even in the case of an accident or for a liquid that is flammable, volatile, and explosive. If the holder 4 or the case 12 can be replaced or newly installed, the conventional thin paper without holes can be used by using the holder or case having the structure shown in FIGS. . Furthermore, when thin paper as shown in FIG. 2 (A) is used in combination with the holder and case having the structure shown in FIGS. It can be executed quickly and is very effective.
[Brief description of the drawings]
FIG. 1 is a diagram showing the structure of a conventional optical liquid leakage sensor.
FIG. 2 is a diagram showing the structure and operating principle of a thin paper for a leak sensor according to the present invention.
FIG. 3 is a view showing an example of a structure of a leak sensor holder according to the present invention.
FIG. 4 is a view showing an example of the structure of an explosion-proof reflective liquid leakage sensor case according to the present invention.
FIG. 5 is a view showing another example of a case for a liquid leakage sensor of the present invention.
FIG. 6 is a diagram showing another example of the present invention.
FIG. 7 is a view showing an example of a transmission type leak sensor according to the present invention.
FIG. 8 is a view showing an example of an explosion-proof transmission type leak sensor according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Floor surface 2, 2a, 2b Liquid leak 4 Holder 7 Air bubble 8 Thin paper 10 Space | gap part 12 Case 14 Light source means 16 Light receiving means 18 Detection means 40 Connector 44, 46 Light transmission means 80 Hole

Claims

White thin paper that becomes transparent due to the absorption of leaked liquid, a thin paper holder that is placed and held horizontally while holding the thin paper and the bottom surface forms a reflection plate, and a bottom portion that is inserted into this holder and has a bottom portion A case constituted by a transparent plate or a semi-transparent plate, a light source means for irradiating light to the thin paper through the transparent plate or the semi-transparent plate, a light receiving means for receiving reflected light from the bottom surface of the holder, and the light receiving A liquid leakage sensor comprising a detecting means for detecting a liquid leakage based on information data from the means, the light source means and the light receiving means are integrated in the case, and the liquid leakage contacts one end of the thin paper In this case, a liquid leakage sensor in which a gap is provided between the holder and the case so that the liquid can permeate quickly, or a white thin paper that becomes transparent due to absorption of the liquid leakage, and this thin paper While placing and holding horizontally A thin paper holder whose surface forms a reflecting plate, a case inserted in the holder and a bottom portion made of a transparent plate or a semi-transparent plate, light source means for irradiating light, and light emitted from this light source From the first light transmission means for irradiating the thin paper via a plate or a translucent plate, the second light transmission means for receiving and transmitting the reflected light from the bottom surface of the holder, and the second light transmission means A liquid leakage sensor is constituted by a light receiving means for receiving the light of the light and a detection means for detecting a liquid leakage based on the information data from the light receiving means, and one end of the first light transmission means and the second light When one end of the transmission means is integrated so as to form an optical system path and is stored in the case, and when leaked liquid comes into contact with one end of the thin paper, the leakage between the holder and the case can be quickly penetrated. In the leak sensor with a gap The shape of the thin paper is a circle or a non-circular shape, and the reflection region is formed in an intermediate portion excluding the outer edge portion and the reflection region of the thin paper so that bubbles do not stay in the reflection region of the thin paper detected by the light receiving means. In contrast, a liquid leakage sensor is characterized in that a hole is provided at an asymmetrical position and shape so that bubbles do not remain in the reflective area of the thin paper even when a large amount of liquid leaks at a time.

White thin paper that becomes transparent due to the absorption of leaked liquid, a thin paper holder that is placed and held horizontally while holding the thin paper and the bottom surface forms a reflection plate, and a bottom portion that is inserted into this holder and has a bottom portion A case constituted by a transparent plate or a semi-transparent plate, a light source means for irradiating light to the thin paper through the transparent plate or the semi-transparent plate, a light receiving means for receiving reflected light from the bottom surface of the holder, and the light receiving A liquid leakage sensor comprising a detecting means for detecting a liquid leakage based on information data from the means, the light source means and the light receiving means are integrated in the case, and the liquid leakage contacts one end of the thin paper In this case, a liquid leakage sensor in which a gap is provided between the holder and the case so that the liquid can permeate quickly, or a white thin paper that becomes transparent due to absorption of the liquid leakage, and this thin paper While placing and holding horizontally A thin paper holder whose surface forms a reflecting plate, a case inserted in the holder and a bottom portion made of a transparent plate or a semi-transparent plate, light source means for irradiating light, and light emitted from this light source From the first light transmission means for irradiating the thin paper via a plate or a translucent plate, the second light transmission means for receiving and transmitting the reflected light from the bottom surface of the holder, and the second light transmission means A liquid leakage sensor is constituted by a light receiving means for receiving the light of the light and a detection means for detecting a liquid leakage based on the information data from the light receiving means, and one end of the first light transmission means and the second light When one end of the transmission means is integrated so as to form an optical system path and is stored in the case, and when leaked liquid comes into contact with one end of the thin paper, the leakage between the holder and the case can be quickly penetrated. In the leak sensor with a gap In the vicinity of the thin paper reflection area on the bottom surface of the holder and / or the bottom of the case, a single or a plurality of convex portions are provided, respectively, and the relative distance between the thin paper and the bottom surface and / or the bottom portion is made non-uniform so A liquid leakage sensor characterized in that bubbles do not remain in the reflective area of the thin paper even when a large amount of liquid overflows at a time.

White thin paper that becomes transparent due to the absorption of leaked liquid, a thin paper holder that is placed and held horizontally while holding the thin paper and the bottom surface forms a reflection plate, and a bottom portion that is inserted into this holder and has a bottom portion A case constituted by a transparent plate or a semi-transparent plate, a light source means for irradiating light to the thin paper through the transparent plate or the semi-transparent plate, a light receiving means for receiving reflected light from the bottom surface of the holder, and the light receiving A liquid leakage sensor comprising a detecting means for detecting a liquid leakage based on information data from the means, the light source means and the light receiving means are integrated in the case, and the liquid leakage contacts one end of the thin paper In this case, a liquid leakage sensor in which a gap is provided between the holder and the case so that the liquid can permeate quickly, or a white thin paper that becomes transparent due to absorption of the liquid leakage, and this thin paper While placing and holding horizontally A thin paper holder whose surface forms a reflecting plate, a case inserted in the holder and a bottom portion made of a transparent plate or a semi-transparent plate, light source means for irradiating light, and light emitted from this light source From the first light transmission means for irradiating the thin paper via a plate or a translucent plate, the second light transmission means for receiving and transmitting the reflected light from the bottom surface of the holder, and the second light transmission means A liquid leakage sensor is constituted by a light receiving means for receiving the light of the light and a detection means for detecting a liquid leakage based on the information data from the light receiving means, and one end of the first light transmission means and the second light When one end of the transmission means is integrated so as to form an optical system path and is stored in the case, and when leaked liquid comes into contact with one end of the thin paper, the leakage between the holder and the case can be quickly penetrated. In the leak sensor with a gap In the case where a large amount of liquid leaks at one time by providing a step by locally inserting a transparent and / or translucent member in the vicinity of the thin paper reflection area at the bottom of the holder and / or the bottom of the case. The liquid leakage sensor is characterized in that no bubbles remain in the reflective area of the thin paper.

White thin paper that becomes transparent due to the absorption of leaked liquid, a thin paper holder that is placed and held horizontally while holding the thin paper and the bottom surface forms a reflection plate, and a bottom portion that is inserted into this holder and has a bottom portion A case constituted by a transparent plate or a semi-transparent plate, a light source means for irradiating light to the thin paper through the transparent plate or the semi-transparent plate, a light receiving means for receiving reflected light from the bottom surface of the holder, and the light receiving A liquid leakage sensor comprising a detecting means for detecting a liquid leakage based on information data from the means, the light source means and the light receiving means are integrated in the case, and the liquid leakage contacts one end of the thin paper In this case, a liquid leakage sensor in which a gap is provided between the holder and the case so that the liquid can permeate quickly, or a white thin paper that becomes transparent due to absorption of the liquid leakage, and this thin paper While placing and holding horizontally A thin paper holder whose surface forms a reflecting plate, a case inserted in the holder and a bottom portion made of a transparent plate or a semi-transparent plate, light source means for irradiating light, and light emitted from this light source From the first light transmission means for irradiating the thin paper via a plate or a translucent plate, the second light transmission means for receiving and transmitting the reflected light from the bottom surface of the holder, and the second light transmission means A liquid leakage sensor is constituted by a light receiving means for receiving the light of the light and a detection means for detecting a liquid leakage based on the information data from the light receiving means, and one end of the first light transmission means and the second light When one end of the transmission means is integrated so as to form an optical system path and is stored in the case, and when leaked liquid comes into contact with one end of the thin paper, the leakage between the holder and the case can be quickly penetrated. In the leak sensor with a gap The bottom surface of the holder and the bottom of the case are parallel to each other, and a groove with a slight inclination angle is provided so that the bubbles do not stay on the bottom of the case, or the bottom of the case is tilted and held in the holder, and the bubbles are removed from the bottom of the case. A liquid leakage sensor characterized by letting it escape to the outside.

White thin paper that becomes transparent due to absorption of leaked liquid, a thin paper holder that is mounted and held on the floor with the light source means or the light receiving means being placed and held horizontally, and the bottom part inserted into this holder Is a transparent plate or a semi-transparent plate, and a light-receiving unit that receives light transmitted from the holder via the transparent plate or the semi-transparent plate, or a light source unit that irradiates light on the thin paper. And a detecting means for detecting leakage based on the information data from the light receiving means, and when the leaked liquid contacts one end of the thin paper, the leaked liquid can penetrate quickly. A liquid leakage sensor in which a gap is provided between the holder and the case, or a white thin paper that becomes transparent due to the absorption of the liquid leakage, and the thin paper is horizontally placed and held and disposed on the floor surface. A thin paper holder A case inserted in a holder and having a bottom made of a transparent plate or a translucent plate, light source means for irradiating light, first transmission means for transmitting irradiation light from the light source to the holder or case, and the holder Alternatively, the second light transmission means for receiving and transmitting the output light of the first light transmission means transmitted to the case as transmitted light through the thin paper, and the light from the second light transmission means is received. A liquid leakage sensor is constituted by a light receiving means and a detection means for detecting liquid leakage based on information data from the light receiving means, and includes one end of the first light transmission means, the thin paper, and the second light transmission means. An optical system path is integrated at one end of the thin paper and placed in the case. When a leaked liquid comes into contact with one end of the thin paper, a gap is formed between the holder and the case so that the leaked liquid can penetrate quickly. The liquid leakage sensor is designed to be The thin paper has a circular or non-circular shape, and a hole is formed in an intermediate portion excluding the outer edge portion and the transmission region of the thin paper so that bubbles do not stay in the transmission region of the thin paper detected by the light receiving means. A liquid leakage sensor is provided, wherein even if a large amount of liquid leakage overflows at once, no bubbles remain in the transmission area of the thin paper.

White thin paper that becomes transparent due to absorption of leaked liquid, a thin paper holder that is mounted and held on the floor with the light source means or the light receiving means being placed and held horizontally, and the bottom part inserted into this holder Is a transparent plate or a semi-transparent plate, and a light-receiving unit that receives light transmitted from the holder via the transparent plate or the semi-transparent plate, or a light source unit that irradiates light on the thin paper. And a detecting means for detecting leakage based on the information data from the light receiving means, and when the leaked liquid contacts one end of the thin paper, the leaked liquid can penetrate quickly. A liquid leakage sensor in which a gap is provided between the holder and the case, or a white thin paper that becomes transparent due to the absorption of the liquid leakage, and the thin paper is horizontally placed and held and disposed on the floor surface. A thin paper holder A case inserted in a holder and having a bottom made of a transparent plate or a translucent plate, light source means for irradiating light, first transmission means for transmitting irradiation light from the light source to the holder or case, and the holder Alternatively, the second light transmission means for receiving and transmitting the output light of the first light transmission means transmitted to the case as transmitted light through the thin paper, and the light from the second light transmission means is received. A liquid leakage sensor is constituted by a light receiving means and a detection means for detecting liquid leakage based on information data from the light receiving means, and includes one end of the first light transmission means, the thin paper, and the second light transmission means. An optical system path is integrated at one end of the thin paper and placed in the case. When a leaked liquid comes into contact with one end of the thin paper, a gap is formed between the holder and the case so that the leaked liquid can penetrate quickly. For the leak sensor In the vicinity of the transparent area of the thin paper at the bottom of the holder and / or the bottom of the case, a single or a plurality of convex portions are provided, and the relative distance between the thin paper and the bottom and / or the bottom is made non-uniform, respectively. A liquid leakage sensor characterized in that even when a large amount of liquid leakage overflows at a time, no bubbles remain in the transmission area of the thin paper.

White thin paper that becomes transparent due to absorption of leaked liquid, a thin paper holder that is mounted and held on the floor with the light source means or the light receiving means being placed and held horizontally, and the bottom part inserted into this holder Is a transparent plate or a semi-transparent plate, and a light-receiving unit that receives light transmitted from the holder via the transparent plate or the semi-transparent plate, or a light source unit that irradiates light on the thin paper. And a detecting means for detecting leakage based on the information data from the light receiving means, and when the leaked liquid contacts one end of the thin paper, the leaked liquid can penetrate quickly. A liquid leakage sensor in which a gap is provided between the holder and the case, or a white thin paper that becomes transparent due to the absorption of the liquid leakage, and the thin paper is horizontally placed and held and disposed on the floor surface. A thin paper holder A case inserted in a holder and having a bottom made of a transparent plate or a translucent plate, light source means for irradiating light, first transmission means for transmitting irradiation light from the light source to the holder or case, and the holder Alternatively, the second light transmission means for receiving and transmitting the output light of the first light transmission means transmitted to the case as transmitted light through the thin paper, and the light from the second light transmission means is received. A liquid leakage sensor is constituted by a light receiving means and a detection means for detecting liquid leakage based on information data from the light receiving means, and includes one end of the first light transmission means, the thin paper, and the second light transmission means. An optical system path is integrated at one end of the thin paper and placed in the case. When a leaked liquid comes into contact with one end of the thin paper, a gap is formed between the holder and the case so that the leaked liquid can penetrate quickly. The liquid leakage sensor is designed to be The bottom surface of the holder and the bottom of the case are parallel to each other, and a groove with a slight inclination angle is provided so that the bubbles do not stay on the bottom of the case, or the bottom of the case is tilted and held in the holder. Leakage sensor characterized by letting it escape to the outside.

Liquid leakage sensor according to any one of claims 1 to 7 wherein the light transmission means is an optical fiber.