JP3824873B2

JP3824873B2 - Leak detection line

Info

Publication number: JP3824873B2
Application number: JP2001077778A
Authority: JP
Inventors: 保小堀; 正敏青木; 健雄大永
Original assignee: Tatsuta Electric Wire and Cable Co Ltd
Current assignee: Tatsuta Electric Wire and Cable Co Ltd
Priority date: 2001-03-19
Filing date: 2001-03-19
Publication date: 2006-09-20
Anticipated expiration: 2021-03-19
Also published as: JP2002277341A

Description

【０００１】
【発明の属する技術分野】
本発明は、水または水と油の混合液のような非絶縁性液体の漏洩、浸入等を検知するのに用いられる漏液検知線に関し、特に検知対象液に対する耐液性に優れ、高湿度などにより誤動作することがなく、かつ安価な漏液検知線に関するものである。
【０００２】
【従来の技術】
漏液検知線には、種々のタイプがあるが、原理的には複数の線状導体を平行に配置し、その線状導体間の電気特性の変化を検知するものが多く用いられている。図８、図９は従来の漏液検知線の例を示す斜視図である。
図８に示す漏液検知線２０は、ほぼ平行に配設された２本の電極線２１ａ，２１ｂを２枚の非吸湿性の絶縁フィルム２２ａ，２２ｂで挟着・支持した偏平条体で、上側の絶縁フィルム２２ａには、電極線２１ａ，２１ｂが互いに向き合って露出するように、長さ方向に沿って間欠的に開口２３，２３・・・が設けられている。このタイプの漏液検知線２０は、例えばゴルフ場、農園などの土中に埋設して電極線２１ａ，２１ｂ間の電気抵抗を測定することにより、土壌の湿度を検知する場合などに用いられる（実公平６−２６１４７号公報参照）。
また、漏液が発生しそうな場所に布設され、漏液が開口２３，２３内の導体２１ａ，２１ｂにまたがって触れると、電流漏洩路が構成されるので、電気抵抗が変化する。
開口２３，２３が長さ方向に沿って間欠的に設けられているため、広い場所の平均湿度を制御するのには問題ないが、局部的な微量な漏液をいち早く検知するにはその間欠性のために検知にばらつきが生じるという問題がある。また、電極線に露出部分があるため、使用場所の雰囲気や漏液によって腐食されないステンレス等の金属線を用いる必要があり高価になる。
【０００３】
図９に示す漏液検知線は３０は、電極線３１ａ，３２ａをそれぞれポリエチレン糸からなる内部編組体３１ｂ，３２ｂによって被覆された線心３１，３２を撚りあわせた上にテトロン糸からなる外部編組体３３を被覆した漏液検知線である。このタイプの漏液検知線は、例えばコンピュータ室など水分を嫌う設備や物品を収納する場所への漏液、浸水を検知するのに用いられる（実公昭６２−４５３８８）。この漏液検知線３０は、外部編組体３３に吸液性、通気性があり、内部編組体３１ｂ，３２ｂにも通液性があるので、局部的で微量な漏液でも検知することができる。
しかし、漏液がなくても高湿度で誤動作したり、対応する必要のないごく微量な漏液をも検知してしまうという問題がある。また、内部編組体、外部編組体とも通気性、通液性があるため、電極線３１ａ，３２ａは露出しているのと同様、使用場所の雰囲気や漏液によって腐食されるおそれがある。
【０００４】
【発明が解決しようとする課題】
本発明は、上記の問題点を解消しようとするものであって、
請求項１乃至４に記載の発明は、電極線の線状導体が腐食されることがなく、検知対象液に対する耐液性に優れ、結露や高湿度などにより誤動作することがなく、かつ安価な漏液検知線の提供を課題とする。
【０００５】
また、漏液位置を容易に検知しうる漏液検知線の提供を課題とする。
【０００６】
請求項５乃至６に記載の発明は、請求項１乃至４記載の発明の課題に加えて、導電性物体などによって電極線間が短絡されるおそれがなく、かつ検知感度を調整しやすく、ばらつきの小さい漏液検知線の提供を課題とする。
【０００７】
【課題を解決するための手段】
前述した課題を解決するために、本発明の請求項１記載の発明は、ほぼ平行に配設された複数の電極線の間に介在線を介在させて連接し、一体化してなる漏液検知線であって、前記電極線は、線状導体の上に耐液性で半導電性の高分子部材を被覆してなり、前記介在線は、線状導体の上に、少なくとも表面が耐液性で非撥液性の絶縁部材を被覆してなるものであり、前記複数本の電極線のうち１本の電極線の線状導体は、導体抵抗が長さ方向に均一な漏液位置検知線であって、前記漏液位置検知線の導体抵抗は、前記介在線の線状導体の導体抵抗を無視し得るほど大きいことを特徴とする漏液検知線である。
【０００８】
ここに、耐液性とは検知対象液によって特性の劣化が生じにくく使用期間中は電極線又は介在線としての機能を保持する性質をいう。電極線は、線状導体の上に耐液性で半導電性の高分子部材を被覆してあるので、線状導体が腐食されることがなく、また線状導体間に電圧を加えれば、電極線間には長さ方向にそって一様な電界が生じ、局部的な微量の漏液でも検知することができる。また、電極線間に少なくとも表面が耐液性で非撥液性の絶縁部材からなる介在線を介在させて連接し、一体化してあるので、結露や高湿度によって誤動作することがない。また、介在線は、少なくとも表面が耐液性で非撥液性の絶縁部材を被覆してあるので、電極線間に浸入した漏液は撥じかれることなく絶縁部材表面をぬらし、またそれによって絶縁部材の特性が劣化することもないので、漏液の浸入の程度のみに応じて電極線間の特性が変化する。
【０００９】
請求項２記載の発明は、請求項１記載の漏液検知線において、
前記電極線の被覆は、導電性粉を含有する高分子部材からなることを特徴とする。
これにより、適度の導電性を有する半導電性の高分子部材が安価に得られる。
【００１０】
請求項３記載の発明は、請求項１又は２記載の漏液検知線において、
前記電極線の被覆及び前記介在線の絶縁部材は、基材がともに押出成形可能な高分子部材からなることを特徴とする。
これにより、一括押し出しが可能となり、電極線及び介在線の形成と連接・一体化が同時に行われる。
【００１１】
請求項４記載の発明は、請求項１乃至３のいずれかに記載の漏液検知線において、
前記電極線及び前記介在線は、外径がほぼ等しい円柱状であることを特徴とする。
これにより、連接・一体化される電極線・介在線の外径がほぼ等しいので、床面等の平面上に載置したとき、フィットしやすくしかも矩形柱状などに比べて被覆材料が少なくてすむ。
【００１３】
請求項５記載の発明は、請求項１乃至４のいずれかに記載の漏液検知線において、前記電極線及び前記介在線に外接して包被する保護編組体を有することを特徴とする。この保護編組体により電極線が保護されるので導電性物体によって電極線間が短絡されたりするのを防ぐことができ、また漏液の検知感度を調整することができる。
【００１４】
請求項６記載の発明は、請求項５記載の漏液検知線において、前記保護編組体は、モノフィラメント糸からなることを特徴とする。これにより、埃で汚れたり、編組体からの発塵を無くすことができる。
【００１５】
【発明の実施の形態】
本発明の実施の形態を、図示例にもとづいて説明する。
図１は、本発明の第１の実施形態の斜視図、図２は、その横断面図、図３は、第２の実施形態の横断面図、図４は、第３の実施形態の横断面図、図５は、第４の実施形態の斜視図、図６は、第２の実施形態の使用方法の説明図、図７は、実施例及び比較例の検知特性図である。
【００１６】
図１及び図２において、漏液検知線１は、ほぼ平行に配設された複数の電極線３、３の間に介在線２を介在させて連接し、一体化したものである。
そして、電極線３，３は、線状導体３ａ、３ａの上に耐液性で半導電性の高分子部材３ｂ、３ｂを被覆したものであり、介在線２は、線状導体２ａの上に少なくとも表面が耐液性で非撥液性の絶縁部材２ｂを被覆したものである。
これら電極線３，３及び介在線２は、ほぼ平行に配設され、例えば接着剤により接着されて一体化され、又は一体に押し出し成形される。４は、その連接部である。
ここに、耐液性とは検知対象液によって特性の劣化が生じにくく使用期間中は電極線又は介在線としての機能を保持する性質をいう。すなわち、検知対象液が水、酸、アルカリであれば、耐水性、耐酸性、耐アルカリ性ということになる。また、非撥液性とは、使用期間中、検知対象液を撥じかずぬれやすい性質を保持することをいう。
【００１７】
例えば、もっともよく使われる漏水の検知であれば、電極線の被覆３ｂ、３ｂも介在線の絶縁部材２ｂも基材がポリ塩化ビニルなどのプラスチックが安価でかつ押し出し成形容易であるから好ましい。また、電極線の方だけカーボンブラックなどの導電性粉を混入したものを用いれば容易に半導電性の被覆が得られる点でも好ましい。さらに、基材が同じであれば、一括押し出し成形も容易であり、一体化に接着剤を用いる必要がない。
酸やアルカリを検知する場合には、耐酸性、耐アルカリ性があって比較的安価なポリチレンなどが好ましい。
介在線２の線状導体２ａ及び電極線３，３の線状導体３ａ、３ａとしては、銅より線、すずめっき銅より線などが低抵抗であり、可とう性が良いなどの点で好ましい。
【００１８】
形状は、外径がほぼ等しい円柱状であることが、取り扱い性がよく、床面等の平面上に載置したとき、フィットしやすくしかも矩形柱状などに比べて被覆材料が少なくてすむので好ましいが、これに限定されるものではない。外径が異なってもよく、四角柱状、六角柱状、など種々の形状が選択可能である。
また、この例では介在線２は、中心に線状導体２ａを有するものとし、表面を耐液性で非撥液性の絶縁部材としたが、もちろん線状導体がなく全体が耐液性で非撥液性の絶縁部材からなるものであってもよい。要は、検知対象液が電極線間に浸入したとき、それを撥じくことがなく、電極線間に導電路が形成されるものであればよい。
【００１９】
図３は、第２の実施形態の横断面図である。この漏液検知線７においては、２本の電極線３，５のうち、電極線５の線状導体５ａが、電極線３、介在線２の線状導体３ａ、２ａにくらべ単位長さあたりの導体抵抗値が大きいものとした点で第１の実施形態と異なるものである。
線状導体５ａとしては、例えばカンタル線（カンタル・ガデリウス社製のニッケルクロム合金線）など単位長さあたりの導体抵抗が線状導体２ａの銅より線や錫メッキ軟銅より線のそれを無視し得る程度に高いものが用いられる。これは、以下に述べる方法で漏液位置を検知する際の誤差を小さくするためである。
【００２０】
次に、図６にもとづき、漏液検知線７を用いて漏液位値Ｐ（Ｑ）を検知する方法について説明する。
図６において、Ｂは直流電源、Ｖは直流電圧計、４０は定電流制御器、Ａは直流電流計、５０は、開閉器、６０は、近端遠端切り換えスイッチであり、図６（ａ）は、漏液検知線７の近端Ｉ，Ｊから漏液位置Ｐ，Ｑまでの距離Ｘを測定する場合、図６（ｂ）は、漏液検知線７の遠端Ｆ，Ｈから漏液位置Ｐ，Ｑまでの距離Ｙを測定する場合の結線図を示している。
ここにおいて、電極線５は、線状導体５ａが、漏液位置検知線となり、介在線２の線状導体２ａは、リード線の働きをする。
近端遠端切り換えスイッチ６０は、主極６１，６２と、近端側極６３，６４及び遠端側極６５，６６で構成されている。
【００２１】
図６（ａ）においては、近端遠端切り換えスイッチ６０は、近端側に接続されている。したがって、定電流Ｉｃは、直流電源Ｂの〔＋〕側から、漏液検知線７の近端Ｊを通り、線状導体３ａの漏液点Ｑ，Ｐを経由して線状導体５ａに流れ、その近端Ｉに戻り、極６６→６３→６１を介して、直流電源Ｂの〔−〕側（接地点ｇ）に流れる。
そのとき、直流電圧計Ｖには、線状導体２ａを介して、Ｐ点の電位、すなわち漏液点Ｐから近端Ｉ、極６６−６３−６１を介して、接地点ｇまでの電位差が測定されることになる。近端Ｉから接地点ｇまでのリード線抵抗が線状導体５ａのＰ−Ｉ間の抵抗に比べて無視しうる程度であるから、測定される電圧Ｖ_Xは、線状導体５ａのＰ−Ｉ間の電圧降下にほぼ等しい。線状導体５ａの導体抵抗が長さ方向に均一であり、単位長さあたりの導体抵抗値をＲ₅とし、漏液検知線７の近端Ｉから漏液点Ｐまての距離をＸとすると、
Ｖ_X＝Ｉｃ×Ｒ₅×Ｘ (1)
【００２２】
図６（ｂ）においては、近端遠端切り換えスイッチ６０は、遠端側に接続されている。したがって、定電流Ｉｃは、直流電源Ｂの〔＋〕側から、漏液検知線７の近端Ｊを通り、線状導体３ａの漏液点Ｑ，Ｐを経由して線状導体５ａに流れ、その遠端Ｆを経由して、Ｇから線状導体２ａの近端Ｋに戻り、極６５→６１を介して、直流電源Ｂの〔−〕側（接地点ｇ）に流れる。
そのとき、直流電圧計Ｖには、線状導体５ａを介して、Ｐ点の電位、すなわち漏液点Ｐから遠端Ｆ、Ｇを介し、介在線２の線状導体２ａの近端Ｋ、極６５−６１を介して、接地点ｇまでの電位差が測定されることになる。ここで、線状導体５ａの単位長さあたりの導体抵抗Ｒ₅が線状導体２ａの単位長さあたりの導体抵抗Ｒ₂を無視し得るほどに大きく、線状導体５ａのＰ−Ｆ間の電圧降下が、線状導体２ａのＧ−Ｋ間の電圧降下を無視し得るほどに大きいものとすると、測定される電圧Ｖ_Yは、線状導体５ａのＰ−Ｆ間の電圧降下にほぼ等しい。線状導体５ａの導体抵抗が長さ方向に均一であり、単位長さあたりの導体抵抗値をＲ₅とし、漏液検知線７の全長をＬ、漏液点Ｐから遠端Ｆまでの距離をＹとすると、
Ｖ_Y＝Ｉｃ×〔（Ｒ₅×Ｙ）＋（Ｒ₂×Ｌ）〕 (2)
【００２３】
Ｉｃ，Ｒ₅，Ｒ₂、Ｌが既知であるから、式▲１▼及び▲２▼から漏液点までの距離Ｘ又はＹを求めることができる。
但し、線状導体５ａ及び２ａの単位長さあたりの抵抗Ｒ₅及びＲ₂は温度により多少変動するから温度係数に基づいて補正することも考えられるが、補正を必要としない方法もある。
すなわち、式(2) の両辺を式(1) の両辺で割ると、
Ｖ_Y／Ｖ_X＝〔（Ｒ₅×Ｙ）＋（Ｒ₂×Ｌ）〕／（Ｒ₅×Ｘ） (3)
しかるに、
Ｌ＝Ｘ＋Ｙ (4)
であるから、

線状導体２ａの単位長さあたりの導体抵抗Ｒ₂が線状導体５ａの単位長さあたりの導体抵抗Ｒ₅に比べて無視し得るほどに小さいと次の近似式が成り立つ。
Ｖ_Y／Ｖ_X＝Ｙ／Ｘ (5)
式(4) から、
Ｙ＝Ｌ−Ｘ
であるから、これを式(5) に代入すると、

同様にして、
Ｙ＝Ｌ×〔Ｖ_Y／（Ｖ_X＋Ｖ_Y）〕 (7)
したがって、Ｖ_XやＶ_Yが測定されると、近端又は遠端から漏液点Ｐ（Ｑ）までの距離Ｘ又はＹは、線状導体５ａ，２ａの単位長さあたりの導体抵抗値に関係なく得られる。
【００２４】
図４は、第３の実施形態の横断面図である。第１の実施形態の漏液検知線１が２本の電極線３，３の間に１本の介在線２を連接し、一体化したものであるのに対し、この漏液検知線８は、３本の電極線３，３，３の間に２本の介在線２，２を互いに隣接するように連接４，４し、一体化したものである。
例えば、真ん中の電極線を直流電源の〔＋〕側に、両側の電極線を〔−〕側に接続して、電極線間の絶縁抵抗を監視するようにすれば、第１の実施形態よりも幅方向に広い範囲の漏液を検知できる。
【００２５】
図５は、第４の実施形態の斜視図である。この漏液検知線１０は、第１の実施形態の漏液検知線１の上に電極線３，３及び介在線２に外接するように吸液性の糸からなる保護編組体１１で包被したものである。
電極線の被覆が半導電性の高分子材料で形成されているため、導電性の物体が接触することがあっても、保護編組体１１を設けてあると、それによって電極線間が短絡され漏液と誤認されるのを防ぐことができる。また、編組密度を調整することによって検知感度を適度に調整することができ、検知感度のばらつきも小さくなる。
また、電極線間の距離があるので、保護編組体１１を設けても、結露等によって誤動作することはない。
【００２６】
保護編組体１１を構成する糸は、テトロンなどの合成樹脂の糸が漏液にぬれたあとの回復性の点で好ましい。
特に、モノフィラメント状の糸であると埃がついたり、毛羽立ったり、発塵しないものが好ましい。マルチフィラメント状の糸の場合は吸液性はよいが、埃が付着しやすく、毛羽立ちを生じたりするため、感度にばらつきを生じるおそれがあるが、モノフィラメント状の糸であれば、その心配はないからである。
【００２７】
【実施例】
本発明の有効性を数値的に実証する実施例を以下に示す。
実施例
図１及び図２に示す構成の漏液検知線であって、表１に示す構造・寸法の１０ｍの試料を３本作製した。なお、電極線と介在線は接着剤によって連接し、一体化した。また、電極線の被覆、介在線の絶縁部材は、ともにポリ塩化ビニル樹脂に可塑剤、難燃剤、安定剤を配合したものを基材とし、電極線の被覆の方は、それに加えてカーボンを２３重量％配合し、半導電性としたものである。
【００２８】
【表１】

【００２９】
比較例
上記実施例と比較するため図９に示す従来の漏液検知線であって、表２に示す構造・寸法の１０ｍの試料を１本作製した。
【００３０】
【表２】

【００３１】
試験方法
上記実施例、比較例の各試料のほぼ中央にメス・ピペットを用いて水滴を滴下しつつ、電極線間の交流６０Ｈｚにおける交流抵抗を測定した。
その結果を図７に示す。
比較例の試料は０．５ｃｃ程度の滴下量になると、交流抵抗は５ｋΩ程度に下がってしまうが、実施例の場合５ｋΩ以上であり、１．１ｃｃ程度で５ｋΩになる。したがって、検知レベルを従来どおり５ｋΩとした場合、比較例のものは当然検知してしまう。結露等によつて、この試験の０．５ｃｃ程度の滴下量に相当する水滴が生じるおそれがあるので、比較例に示す従来のタイプのものは誤動作する可能性があり、検知感度が良すぎる。
これに対し実施例の漏液検知線は、検知レベルを従来どおり５ｋΩ程度にしておけば、それによって誤動作することはない。
【００３２】
【発明の効果】
以上に説明したように、本発明の請求項１記載の発明によれば、電極線が、線状導体の上に耐液性で半導電性の高分子部材を被覆してあるので、線状導体が腐食されることがなく、また線状導体間に電圧を加えれば、電極線間には長さ方向にそって一様な電界が生じ、局部的な微量の漏液でも検知することができる。また、電極線間に介在線を介在させて連接し、一体化してあるので、結露や高湿度によって誤動作することがない。また、介在線は、少なくとも表面が耐液性で非撥液性の絶縁部材からなるので、電極線間に浸入した漏液は撥じかれることなく絶縁部材表面をぬらす。またそれによって絶縁部材の特性が劣化することがなく、漏液の浸入の程度のみに応じて電極線間の特性が変化するので、基準値を適当に選ぶことによって、結露や高湿度によって誤動作することがなく確実に漏液を検知することができる。また、漏液位置検知線の線状導体の導体抵抗は、長さ方向に均一で、介在線中の線状導体の導体抵抗を無視し得る程度に大きいので、漏液検知線の端部から漏液位置までの漏液位置検知線の導体抵抗の測定により、漏液位置の検知ができ、しかも介在線中の線状導体をリード線として用いることができるので、別にリード線を設ける必要がなく、スペースを節約できる。
【００３３】
請求項２記載の発明によれば、請求項１の発明の効果に加えて、
電極線の被覆が、導電性粉を含有する高分子部材で構成されるので、適度の導電性を有する半導電性の高分子部材が安価に得られる。
【００３４】
請求項３記載の発明によれば、請求項１又は２記載の発明の効果に加えて、
電極の被覆及び介在線の絶縁部材は、基材がともに押出成形可能な高分子部材で構成され、一括押し出しが可能であり、電極線及び介在線の形成と連接・一体化が同時に行われるので、工程が短縮される。
【００３５】
請求項４記載の発明によれば、請求項１乃至３のいずれかに記載の発明の効果に加えて、
連接・一体化される電極線・介在線の外径がほぼ等しい円柱状であるので、取り扱いが容易であり、床面等の平面上に載置したとき、フィットしやすくしかも矩形柱状などに比べて被覆材料が少なくてすむ。
【００３７】
請求項５記載の発明によれば、請求項１乃至４のいずれかに記載の発明の効果に加えて、電極線及び介在線に外接して保護編組体を包被してあるので、導電性物体によって電極線間が短絡されたりするのを防ぐことができるとともに、編組密度などを変えることにより、検知感度を調整でき、またそのばらつきを小さくすることができる。
【００３８】
請求項６記載の発明によれば、請求項５記載の発明の効果に加えて、保護編組体が、モノフィラメント糸からなるので、埃でよごれたり、編組体からの発塵が無く、感度の調整がしやすい。
【図面の簡単な説明】
【図１】本発明の第１の実施形態の斜視図である。
【図２】本発明の第１の実施形態の横断面図である。
【図３】本発明の第２の実施形態の横断面図である。
【図４】本発明の第３の実施形態の横断面図である。
【図５】本発明の第４の実施形態の斜視図である。
【図６】本発明の第２の実施形態の使用方法の説明図である。
【図７】本発明の実施例及び比較例の検知特性図である。
【図８】従来の漏液検知線の斜視図である。
【図９】従来の別の漏液検知線の斜視図である。
【符号の説明】
１，７，８，１０漏液検知線
２介在線
３電極線
４連接部
１１保護編組体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a leak detection line used to detect leakage, intrusion, etc. of non-insulating liquid such as water or a mixture of water and oil, and in particular, has excellent liquid resistance against detection target liquid and high humidity. The present invention relates to an inexpensive leak detection line that does not malfunction due to the above.
[0002]
[Prior art]
There are various types of leak detection lines, but in principle, a plurality of lines are used in which a plurality of linear conductors are arranged in parallel and changes in electrical characteristics between the linear conductors are detected. 8 and 9 are perspective views showing examples of conventional leak detection lines.
The liquid leakage detection line 20 shown in FIG. 8 is a flat strip that sandwiches and supports two

electrode wires

21a and 21b arranged substantially in parallel with two non-hygroscopic

insulating films

22a and 22b. The upper insulating film 22a is provided with

openings

23, 23,... Intermittently along the length direction so that the

electrode wires

21a, 21b are exposed to face each other. This type of leakage detection line 20 is used, for example, when detecting the humidity of the soil by burying it in the soil of a golf course, a farm or the like and measuring the electrical resistance between the

electrode wires

21a and 21b (see FIG. (See Japanese Utility Model Publication No. 6-26147).
Further, when the liquid leakage is laid in a place where liquid leakage is likely to occur and the liquid leakage touches the

conductors

21a and 21b in the

openings

23 and 23, a current leakage path is formed, so that the electric resistance changes.
Since the

openings

23 and 23 are provided intermittently along the length direction, there is no problem in controlling the average humidity in a wide area, but in order to quickly detect a small amount of local liquid leakage, the intermittent There is a problem that variation occurs in detection due to the characteristics. Further, since the electrode wire has an exposed portion, it is necessary to use a metal wire such as stainless steel that is not corroded by the atmosphere in the place of use or liquid leakage, which is expensive.
[0003]
The liquid leakage detection line 30 shown in FIG. 9 is formed by twisting the

wire cores

31 and 32 covered with the

inner braids

31b and 32b made of polyethylene yarn on the

electrode wires

31a and 32a, respectively, and then forming the outer braid made of tetron yarn. This is a leak detection line covering the body 33. This type of leak detection line is used to detect leaks and water ingress to equipment that dislikes moisture, such as a computer room, or a place for storing articles (Japanese Utility Model Publication No. 62-45388). The liquid leakage detection line 30 has liquid absorption and air permeability in the outer braid 33 and liquid permeability in the

internal braids

31b and 32b, so that even a small amount of liquid leakage can be detected locally. .
However, there is a problem that even if there is no leakage, it malfunctions at high humidity, or even a very small amount of leakage that does not need to be dealt with is detected. In addition, since both the inner braid and the outer braid are air permeable and liquid permeable, the

electrode wires

31a and 32a may be corroded by the atmosphere or liquid leakage in the place of use, just as the

electrode wires

31a and 32a are exposed.
[0004]
[Problems to be solved by the invention]
The present invention is to solve the above problems,
The invention according to claims 1 to 4 is such that the linear conductor of the electrode wire is not corroded, has excellent liquid resistance against the liquid to be detected, does not malfunction due to condensation or high humidity, and is inexpensive. The issue is to provide a leak detection line.
[0005]
It is another object of the present invention to provide a leak detection line that can easily detect the leak position.
[0006]
In addition to the problems of the inventions described in claims 1 to 4 , the inventions described in claims 5 to 6 do not cause a short circuit between the electrode wires due to a conductive object or the like, can easily adjust the detection sensitivity, and vary. The problem is to provide a liquid leakage detection line with a small size.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problem, the invention according to claim 1 of the present invention is a liquid leakage detection system in which intervening wires are interposed between a plurality of electrode wires arranged substantially in parallel and integrated. The electrode wire is formed by coating a liquid conductor and a semiconductive polymer member on a linear conductor , and the interposition wire has at least a liquid resistant surface on the linear conductor. A non-liquid-repellent insulating member is coated, and the linear conductor of one of the plurality of electrode wires has a uniform conductor resistance in the length direction. The liquid leakage detection line is characterized in that a conductor resistance of the leakage position detection line is so large that a conductor resistance of the linear conductor of the interposition line can be ignored .
[0008]
Here, the liquid resistance refers to the property that the characteristics are hardly deteriorated by the liquid to be detected and the function as an electrode wire or an interposition wire is maintained during the period of use. Since the electrode wire is coated with a liquid-resistant and semiconductive polymer member on the linear conductor, the linear conductor is not corroded, and if a voltage is applied between the linear conductors, A uniform electric field is generated between the electrode wires along the length direction, and even a small amount of local liquid leakage can be detected. In addition, since the electrode wires are connected and integrated with an interposition wire made of an insulating member having at least a liquid- resistant and non-liquid-repellent insulating member between the electrode wires, malfunction does not occur due to dew condensation or high humidity. In addition, since the interposition wire has at least the surface covered with a liquid- resistant and non-liquid-repellent insulating member, the leakage that has entered between the electrode wires wets the surface of the insulating member without being repelled. Since the characteristics of the insulating member are not deteriorated, the characteristics between the electrode lines change depending only on the degree of intrusion of the liquid leakage.
[0009]
The invention according to claim 2 is the leak detection line according to claim 1,
The electrode wire coating is made of a polymer member containing conductive powder.
Thereby, a semiconductive polymer member having moderate conductivity can be obtained at a low cost.
[0010]
The invention according to claim 3 is the liquid leakage detection line according to

claim

1 or 2,
The electrode wire covering and the intervening wire insulating member are both made of a polymer member whose base material can be extruded.
Thereby, batch extrusion becomes possible, and formation, connection, and integration of the electrode wire and the interposition wire are performed simultaneously.
[0011]
According to a fourth aspect of the present invention, in the liquid leakage detection line according to any one of the first to third aspects,
The electrode wire and the interposition wire have a cylindrical shape with substantially the same outer diameter.
As a result, since the outer diameters of the electrode wires and interposition wires to be connected and integrated are substantially equal, when placed on a flat surface such as a floor surface, it is easy to fit and requires less coating material than a rectangular column shape or the like. .
[0013]
According to a fifth aspect of the present invention, in the liquid leakage detection wire according to any one of the first to fourth aspects, a protective braided body that circumscribes and covers the electrode wire and the interposition wire is provided. Since the electrode wire is protected by the protective braided body, it is possible to prevent the electrode wires from being short-circuited by the conductive object, and it is possible to adjust the leakage detection sensitivity.
[0014]
According to a sixth aspect of the present invention, in the liquid leakage detection line according to the fifth aspect , the protective braid is made of a monofilament yarn. As a result, it is possible to eliminate dirt and dust generation from the braided body.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described based on illustrated examples.
1 is a perspective view of a first embodiment of the present invention, FIG. 2 is a cross-sectional view thereof, FIG. 3 is a cross-sectional view of a second embodiment, and FIG. 4 is a cross-section of the third embodiment. FIG. 5 is a perspective view of the fourth embodiment, FIG. 6 is an explanatory view of a method of using the second embodiment, and FIG. 7 is a detection characteristic diagram of the example and the comparative example.
[0016]
1 and 2, the leak detection line 1 is formed by connecting and interposing an intervening line 2 between a plurality of

electrode lines

3 and 3 arranged substantially in parallel.
The

electrode wires

3 and 3 are obtained by coating the linear conductors 3a and 3a with liquid-resistant and

semiconductive polymer members

3b and 3b. The interposition wires 2 are formed on the linear conductors 2a. Further, at least the surface is coated with a liquid-resistant and non-liquid-repellent insulating member 2b.
These

electrode wires

3 and 3 and the interposition wire 2 are disposed substantially in parallel, and are bonded together by, for example, an adhesive, or are integrally formed by extrusion. 4 is the connection part.
Here, the liquid resistance refers to the property that the characteristics are hardly deteriorated by the liquid to be detected and the function as an electrode wire or an interposition wire is maintained during the period of use. That is, if the detection target liquid is water, acid, or alkali, it means water resistance, acid resistance, or alkali resistance. Further, non-liquid repellency means that the liquid to be detected is not easily repelled during the period of use, and the liquid is easily wetted.
[0017]
For example, the most frequently used detection of water leakage is preferable because both the

electrode wire coverings

3b and 3b and the intervening wire insulating member 2b are made of plastic such as polyvinyl chloride, which is inexpensive and easy to extrude. In addition, it is preferable that only the electrode wire is mixed with conductive powder such as carbon black so that a semiconductive coating can be easily obtained. Furthermore, if the base material is the same, batch extrusion molding is easy, and it is not necessary to use an adhesive for integration.
In the case of detecting acid or alkali, it is preferable to use a relatively inexpensive polyylene having acid resistance and alkali resistance.
As the linear conductor 2a of the intervening wire 2 and the linear conductors 3a and 3a of the

electrode wires

3 and 3, a copper stranded wire, a tin-plated copper stranded wire or the like is preferable in terms of low resistance and good flexibility. .
[0018]
It is preferable that the shape is a cylindrical shape having substantially the same outer diameter, because it is easy to handle, and when placed on a flat surface such as a floor surface, it is easy to fit and requires less coating material than a rectangular columnar shape. However, the present invention is not limited to this. The outer diameters may be different, and various shapes such as a rectangular column shape and a hexagonal column shape can be selected.
Further, in this example, the interposition wire 2 has a linear conductor 2a in the center and the surface is a liquid-resistant and non-liquid-repellent insulating member, but of course there is no linear conductor and the whole is liquid-resistant. It may be made of a non-liquid-repellent insulating member. In short, it is sufficient that the liquid to be detected does not repel when the liquid to be detected enters between the electrode lines and a conductive path is formed between the electrode lines.
[0019]
FIG. 3 is a cross-sectional view of the second embodiment. In the liquid leakage detection line 7, of the two

electrode lines

3 and 5, the linear conductor 5 a of the electrode line 5 is per unit length compared to the linear conductors 3 a and 2 a of the electrode line 3 and the interposition line 2. The first embodiment is different from the first embodiment in that the conductor resistance value is large.
As the linear conductor 5a, for example, a conductor resistance per unit length such as Kanthal wire (nickel chrome alloy wire manufactured by Kanthal Gadelius Co.) is neglected from that of the copper of the linear conductor 2a or the wire of tinned annealed copper. High enough to be obtained is used. This is to reduce the error when detecting the leak position by the method described below.
[0020]
Next, a method of detecting the liquid leakage level value P (Q) using the liquid leakage detection line 7 will be described with reference to FIG.
In FIG. 6, B is a DC power source, V is a DC voltmeter, 40 is a constant current controller, A is a DC ammeter, 50 is a switch, and 60 is a near-end / far-end changeover switch. When measuring the distance X from the near ends I and J of the leak detection line 7 to the leak positions P and Q, FIG. 6B shows the leak from the far ends F and H of the leak detection line 7. The connection diagram in the case of measuring the distance Y to the positions P and Q is shown.
Here, in the electrode wire 5, the linear conductor 5 a serves as a leakage position detection line, and the linear conductor 2 a of the interposition wire 2 functions as a lead wire.
The near-end / far-end changeover switch 60 includes

main poles

61 and 62, near-

end side poles

63 and 64, and far-

end side poles

65 and 66.
[0021]
In FIG. 6A, the near end far end changeover switch 60 is connected to the near end side. Therefore, the constant current Ic flows from the [+] side of the DC power supply B through the near end J of the leak detection line 7 to the linear conductor 5a via the leak points Q and P of the linear conductor 3a. Returning to the near end I, it flows to the [−] side (ground point g) of the DC power source B via the poles 66 → 63 → 61.
At that time, the DC voltmeter V measures the potential at the point P via the linear conductor 2a, that is, the potential difference from the leakage point P to the ground point g via the near end I and the pole 66-63-61. Will be. Since the lead wire resistance from the near end I to the ground point g is negligible compared to the resistance between PI of the linear conductor 5a, the measured voltage V _X is P− of the linear conductor 5a. Is approximately equal to the voltage drop across I. It is uniform in the longitudinal direction conductor resistance of the linear conductor 5a, the conductor resistance per unit length and R _5, and the distance of the leakage point P Wait from the proximal end I of the leak detection line 7 X Then
V _X = Ic × R ₅ × X (1)
[0022]
In FIG. 6B, the near-end / far-end changeover switch 60 is connected to the far-end side. Therefore, the constant current Ic flows from the [+] side of the DC power supply B through the near end J of the leak detection line 7 to the linear conductor 5a via the leak points Q and P of the linear conductor 3a. Then, via the far end F, it returns from G to the near end K of the linear conductor 2a, and flows through the pole 65 → 61 to the [−] side (ground point g) of the DC power supply B.
At that time, the direct current voltmeter V is connected to the potential at the point P via the linear conductor 5a, that is, from the leakage point P via the far ends F and G, to the near end K and the pole of the linear conductor 2a of the interposition wire 2. The potential difference to the ground point g is measured via 65-61. Here, the conductor resistance R ₅ per unit length of the linear conductor 5a is so large that the conductor resistance R ₂ per unit length of the linear conductor 2a is negligible, and is between PF of the linear conductor 5a. If the voltage drop is so large that the voltage drop between G and K of the linear conductor 2a is negligible, the measured voltage V _Y is approximately equal to the voltage drop between P and F of the linear conductor 5a. . Is uniform in the longitudinal direction conductor resistance of the linear conductor 5a, the distance of the conductor resistance per unit length and R _5, the total length of the leak detection line 7 L, until the far end F from Moekiten P Is Y,
V _Y = Ic × [(R ₅ × Y) + (R ₂ × L)] (2)
[0023]
Since Ic, R ₅ , R ₂ , and L are known, the distance X or Y from the equations (1) and (2) to the leak point can be obtained.
However, since the resistances R ₅ and R ₂ per unit length of the linear conductors 5a and 2a slightly vary depending on the temperature, it may be corrected based on the temperature coefficient, but there is a method that does not require correction.
That is, if both sides of equation (2) are divided by both sides of equation (1),
V _Y / V _X = [(R ₅ × Y) + (R ₂ × L)] / (R ₅ × X) (3)
However,
L = X + Y (4)
Because

When the conductor resistance R ₂ per unit length of the linear conductor 2a is so small as to be negligible compared to the conductor resistance R ₅ per unit length of the linear conductor 5a, the following approximate expression holds.
V _Y / V _X = Y / X (5)
From equation (4)
Y = L-X
Therefore, if this is substituted into equation (5),

Similarly,
Y = L × [V _Y / (V _X + V _Y )] (7)
Therefore, when V _X and V _Y are measured, the distance X or Y from the near end or the far end to the leakage point P (Q) is the conductor resistance value per unit length of the linear conductors 5a and 2a. You can get it regardless.
[0024]
FIG. 4 is a cross-sectional view of the third embodiment. Whereas the leak detection line 1 of the first embodiment is formed by connecting and interposing one intervening line 2 between the two

electrode lines

3 and 3, the leak detection line 8 is Two intervening

wires

2 and 2 are connected and integrated so as to be adjacent to each other between three

electrode wires

3, 3 and 3.
For example, if the middle electrode wire is connected to the [+] side of the DC power source and the electrode wires on both sides are connected to the [−] side to monitor the insulation resistance between the electrode wires, the first embodiment Can detect a wide range of liquid leakage in the width direction.
[0025]
FIG. 5 is a perspective view of the fourth embodiment. The leak detection line 10 is covered with a protective braid 11 made of a liquid-absorbing thread so as to circumscribe the

electrode lines

3 and 3 and the interposition line 2 on the leak detection line 1 of the first embodiment. It is a thing.
Since the covering of the electrode wire is formed of a semiconductive polymer material, even if a conductive object may come into contact, if the protective braid 11 is provided, the electrode wire is short-circuited thereby. It can be prevented from being mistaken for leakage. Further, by adjusting the braid density, the detection sensitivity can be adjusted appropriately, and the variation in detection sensitivity is reduced.
In addition, since there is a distance between the electrode wires, even if the protective braided body 11 is provided, no malfunction occurs due to condensation or the like.
[0026]
The yarn constituting the protective braid 11 is preferable in terms of recoverability after the yarn of synthetic resin such as Tetron is wetted by leakage.
In particular, a monofilament-like thread is preferred that does not dust, fluff, or generate dust. In the case of multifilament-like yarns, the liquid absorbency is good, but dust is likely to adhere and fluffing may occur, which may cause variations in sensitivity. Because.
[0027]
【Example】
Examples that demonstrate the effectiveness of the present invention numerically are given below.
Example 3 Three 10 m samples having the structure and dimensions shown in Table 1 which are liquid leakage detection lines having the structure shown in FIGS. In addition, the electrode wire and the interposition wire were connected and integrated with an adhesive. In addition, the electrode wire coating and the insulation member for the interposition wire are both made of a material in which a plasticizer, a flame retardant, and a stabilizer are blended with polyvinyl chloride resin, and the electrode wire is coated with carbon. 23% by weight is blended to make it semiconductive.
[0028]
[Table 1]

[0029]
Comparative Example One 10 m sample having the structure and dimensions shown in Table 2, which is the conventional leak detection line shown in FIG.
[0030]
[Table 2]

[0031]
Test Method The AC resistance at 60 Hz AC between the electrode wires was measured while dropping water droplets at approximately the center of each sample of the above Examples and Comparative Examples using a knife pipette.
The result is shown in FIG.
When the drop amount of the sample of the comparative example is about 0.5 cc, the AC resistance is reduced to about 5 kΩ, but in the case of the example, it is 5 kΩ or more, and about 1.1 cc is 5 kΩ. Therefore, when the detection level is set to 5 kΩ as usual, the comparative example is naturally detected. Due to condensation or the like, water droplets corresponding to a drop amount of about 0.5 cc in this test may be generated. Therefore, the conventional type shown in the comparative example may malfunction and the detection sensitivity is too good.
On the other hand, if the detection level of the liquid leakage detection line of the embodiment is set to about 5 kΩ as usual, it will not malfunction.
[0032]
【The invention's effect】
As described above, according to the invention of claim 1 of the present invention, the electrode wire is coated with the liquid-resistant and semiconductive polymer member on the linear conductor. If the conductor is not corroded, and a voltage is applied between the linear conductors, a uniform electric field is generated between the electrode wires along the length direction, and even a small amount of local leakage can be detected. it can. In addition, since the interposition wires are interposed between the electrode wires and are connected and integrated, there is no malfunction due to condensation or high humidity. Further, since the interposition wire is made of an insulating member having at least a surface that is liquid- resistant and non-liquid-repellent, the liquid that has entered between the electrode wires wets the surface of the insulating member without being repelled. In addition, the characteristics of the insulating member are not deteriorated, and the characteristics between the electrode wires change only according to the degree of the intrusion of the liquid. Therefore, malfunction may occur due to condensation or high humidity by appropriately selecting the reference value. It is possible to detect leaking without fail. In addition, the conductor resistance of the linear conductor of the leak detection line is uniform in the length direction and is so large that the conductor resistance of the linear conductor in the interposition line can be ignored. By measuring the conductor resistance of the leak position detection line up to the leak position, the leak position can be detected, and the linear conductor in the interposition wire can be used as the lead wire, so it is necessary to provide a separate lead wire And saves space.
[0033]
According to the invention of claim 2, in addition to the effect of the invention of claim 1,
Since the covering of the electrode wire is composed of a polymer member containing conductive powder, a semiconductive polymer member having moderate conductivity can be obtained at low cost.
[0034]
According to the invention described in claim 3, in addition to the effect of the invention described in

claim

1 or 2,
The electrode covering and the insulating member of the interposition wire are made of a polymer member whose base material can be extruded, and can be extruded together, and the formation and connection / integration of the electrode wire and the interposition wire are performed at the same time. The process is shortened.
[0035]
According to the invention of claim 4, in addition to the effect of the invention of any one of claims 1 to 3,
Since the outer diameters of the connected and integrated electrode wires and intervening wires are cylindrical, it is easy to handle and fits easily when placed on a flat surface such as the floor, compared to rectangular columns. Less coating material.
[0037]
According to the invention described in claim 5 , in addition to the effect of the invention described in any one of claims 1 to 4 , since the protective braid is encased around the electrode wire and the interposed wire, It is possible to prevent the electrode wires from being short-circuited by an object, and to change the braid density or the like, thereby adjusting the detection sensitivity and reducing the variation.
[0038]
According to the invention described in claim 6 , in addition to the effect of the invention described in claim 5 , since the protective braided body is made of monofilament yarn, there is no dirt due to dust or dust generation from the braided body, and the sensitivity adjustment. Easy to do.
[Brief description of the drawings]
FIG. 1 is a perspective view of a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the first embodiment of the present invention.
FIG. 3 is a cross-sectional view of a second embodiment of the present invention.
FIG. 4 is a cross-sectional view of a third embodiment of the present invention.
FIG. 5 is a perspective view of a fourth embodiment of the present invention.
FIG. 6 is an explanatory diagram of how to use the second embodiment of the present invention.
FIG. 7 is a detection characteristic diagram of an example of the present invention and a comparative example.
FIG. 8 is a perspective view of a conventional leak detection line.
FIG. 9 is a perspective view of another conventional leak detection line.
[Explanation of symbols]
1, 7, 8, 10 Leakage detection wire 2 Intervening wire 3 Electrode wire 4 Connection 11 Protection braid

Claims

A leakage detection line formed by connecting and interposing an interposition line between a plurality of electrode lines arranged substantially in parallel,
The electrode wire is formed by coating a liquid-resistant and semiconductive polymer member on a linear conductor,
The interposition wire is formed by coating at least a surface of a linear conductor with a liquid- resistant and non-liquid-repellent insulating member ,
The linear conductor of one electrode line of the plurality of electrode lines is a leakage position detection line whose conductor resistance is uniform in the length direction, and the conductor resistance of the leakage position detection line is the intermediary resistance. A leak detection line characterized in that the conductor resistance of the existing linear conductor is negligible .

2. The leak detection line according to claim 1, wherein the coating of the electrode wire is made of a polymer member containing conductive powder.

3. The liquid leakage detection line according to claim 1, wherein the covering of the electrode wire and the insulating member of the interposition wire are made of a polymer member whose base material can be extruded.

In leak detection line according to any one of claims 1 to 3, wherein the electrode lines and the intervening lines, leak detection line, wherein the outer diameter is substantially equal cylindrical.

In leak detection line according to any one of claims 1 to 4, leak detection line, characterized in that it comprises a protective braid encapsulating circumscribe the electrode lines and the intervening lines.

6. The liquid leakage detection line according to claim 5 , wherein the protective braid is made of monofilament yarn.