JP3606116B2 - Capacitive moisture sensor - Google Patents

Description

【００６６】
ところで、生ゴミの一般的な大きさは、生ゴミ処理機内に投入後直ちに粉砕されて、表２の大きさになる。この表２は生ゴミを実際に種々の目の大きさのふるいにかけて、残留した生ゴミの比率を求めた実測値を示す。
【００６７】
この表２から概ね１５ｍｍ程度の大きさに生ゴミが粉砕されていることが分かる。従って、検知領域として余裕をみて、２０ｍｍ程度以上あれば、検知領域を生ゴミが埋め尽くすということが起きないことが分かった。
【００６８】
【表２】

【００６９】
そこで本発明者らは検知領域を決定する１対の電極１２ａ，１２ｂの寸法や距離と、検知領域との関係を図１１に示す実験用電極部を用いて求めた。
【００７０】
この実験は、厚さ０．１ｍｍで長さが１１５ｍｍの銅箔テープからなる短冊状の１対の電極１２ａ，１２ｂの電極幅Ｗが２４ｍｍ、両電極１２ａ，１２ｂ間の距離Ｐが２ｍｍである電極構成の電極部と、厚さ、長さが上記と同じ銅箔テープからなる短冊状の１対の電極１２ａ，１２ｂの電極幅Ｗが１０ｍｍ、両電極１２ａ，１２ｂ間の距離Ｐが３０ｍｍである電極構成の電極部と、厚さ、長さが上記と同じ銅箔テープからなる短冊状の１対の電極１２ａ，１２ｂの内一方の電極幅Ｗが５ｍｍ、他方の電極幅Ｗが２５ｍｍ、両電極１２ａ，１２ｂ間の距離Ｐが２０ｍｍである電極構成の電極部とを用いて行い、厚さが１ｍｍで一辺の長さが１１５ｍｍの正方形状の底面を持ち、高さが４０ｍｍの箱状の非導電性樹脂ケースＰＣの外底面に各電極１２ａ、１２ｂを貼り着し、樹脂ケースＰＣの内部に水を入れ、この時の水位を５ｍｍ、１０ｍｍ、２５ｍｍ、…と増加させていったときの電極間容量を測定したところ、夫々の電極部の電極間容量は図１２に示すような値となった。図１２中イは電極１２ａ，１２ｂの電極幅が２４ｍｍ、両電極１２ａ，１２ｂ間の距離が２ｍｍである電極構成の電極部の電極間容量の測定結果、ロは電極１２ａ，１２ｂの電極幅が１０ｍｍ、両電極１２ａ，１２ｂ間の距離が３０ｍｍである電極構成の電極部の電極間容量の測定結果、ハは電極１２ａ，１２ｂの内一方の電極幅が５ｍｍ、他方の電極幅が２５ｍｍ、両電極１２ａ，１２ｂ間の距離が２０ｍｍである電極構成の電極部の電極間容量の測定結果を示す。
【００７１】
この結果から水位を増やしても電極間容量が変化しなくなる水位を、電極面からの奥行き方向の検知領域Ｄとすると、検知領域Ｄの奥行き寸法が電極１２ａ，１２ｂの互いに並行し且つ遠い方の端縁間、つまり全体幅（５０ｍｍ）の距離の約半分であることが分かった。
【００７２】
而して、上述の条件を満たした、生ゴミ処理機の水分量の検知対象物である生ゴミ処理剤の水分量を検出する水分量センサを構成することにより、正確に生ゴミ処理剤の水分量を検知できるようになった。
【００７３】
図１３（ａ）は本実施形態の電極部１２の一例を示しており、この例は図７（ａ）の電極形状に対応するもので中央の電極１２ａの一辺の寸法をｄ０とし、周囲の電極１２ｂの幅寸法をｄ１とし、電極１２ａの辺と、これに対向する電極１２ｂの内側の辺との間の寸法をｄ２とし、一対の電極１２ａ，１２ｂの大きさにより決定される検知領域Ｄの奥行き寸法を上記の条件である２０ｍｍ以上を満足するために、本発明者らは実験の結果に基づいて、両電極１２ａ，１２ｂの並行する端縁の内互いに遠い方にある端縁間の距離（＝ｄ１＋ｄ２＋ｄ０）が図１３（ｂ）に示すように検知領域Ｄの奥行き寸法２０ｍｍ（Ｌ／２）の倍（Ｌ）以上となるように電極１２ａ、１２ｂの幅寸法及び間隔を設定する。
【００７４】
図１４（ａ）（ｂ）は直径がｄ０の円形状の電極１２ａに対して内径が（ｄ２×２）＋ｄ０で幅がｄ１の円環状の電極１２ｂとで電極部１２を構成した例（図７（ｂ）に対応）を示しており、この例においても、両電極１２ａ、１２ｂの並行する端縁の遠方の間の距離（ｄ１＋ｄ２＋ｄ０）が検知領域Ｄの奥行き寸法２０ｍｍ（Ｌ／２）の倍以上（Ｌ）となるように電極１２ａ、１２ｂの幅寸法及び間隔を設定する。
【００７５】
（実施形態７）
ところで、電極１２ａを例えば図１５（ａ）（ｂ）に示すように正方形の電極１２ａと、それを囲むように配設した四角枠状の電極１２ｂとで電極部１２を構成したとき、中央の正方形の一辺の寸法ｄ０を、周囲の電極１２ｂの幅ｄ１より大きく設定した場合、両電極１２ａ，１２ｂの間に浮遊容量（細線の矢印は電気力線を示す）が発生するとともに、電極１２ａと大地との間に浮遊容量（太実線の矢印は電気力線を示す）が発生する。この浮遊容量の寄生先の電位が変動、例えば大地の電位が揺れることによって、誤動作が生じる。特に容器Ｂが金属製では、他の電子部品の漏れ電流など、どのような電気的挙動を示すか定かでない。従って極力浮遊容量を小さくする方が安全である。
【００７６】
本実施形態では、図１６（ａ）（ｂ）又は図１７に示すように絶縁構造物１５の面と同一面となるように凹部１７ａ、１７ｂに埋め込み配設した正方形状又は円形状の電極１２ａの一辺の長さ又は直径、つまり幅をｄ０としたとき、周囲の電極１２ｂの幅ｄ１を同一（ｄ１＝ｄ０）としてある。尚図中ｄ２は両電極１２ａ、１２ｂ間の距離を示す。
【００７７】
従って本実施形態の構成では電気力線の密度が電極１２ａ、１２ｂで同一になるため浮遊容量が減少し、その結果、大地の電位などの変動や、漏れ電流による電位の変動に対しても誤動作の少ない水分量センサを実現できる。
（実施形態８）
上記実施形態１乃至７は電極１２ａ、１２ｂからなる電極部１２を絶縁構造物１５に設け、該絶縁構造物１５を容器Ｂに設けてある開口部１６に取り付ける構成であるが、対の電極１２ａ、１２ｂを共に絶縁構造物１５に設けるため、絶縁構造物１５が大型化し、そのため開口部１６が大きくなり、結果容器Ｂの強度を弱める恐れがある。
【００７８】
そこで本実施形態では、容量検知回路１３の一方の電極接続端に接続する電極１２ａはそのままであるが、他方の電極接続端に接続する電極１２ｂを大地で構成する構造とする。
【００７９】
図１８（ａ）は平板状の絶縁構造物１５の凹部１７ａに電極１２ａを埋め込んで、電極１２ａの電極面と容器Ｂの壁面とを同一面とした例を示し、図１８（ｂ）は絶縁構造物１５に凹所２０を形成して、その凹所２０の底部に設けた凹部１７ａに電極１２ａを埋め込んだ例を示す。
【００８０】
これら例図で分かるように絶縁構造物１５に設ける電極が１２ａの一つとなるため、絶縁構造物１５が小型となり、結果絶縁構造物１５を取り付けるために容器Ｂに設ける開口部１６の開口面積を小さくすることができ、容器Ｂの強度を弱めることはない。尚容量検知回路１３の一方の電極接続端には電極１２ａを、他方の電極接続端には大地を接続して、容量検知回路１３は大地たる電極１２ｂと電極１２ａとの間の検知対象物による静電容量Ｃｘの値を検知し、出力部１４より静電容量Ｃｘの値に対応した例えば電圧信号を出力する。
（実施形態９）
上記実施形態８は、容量検知回路１３の他方の電極接続端に接続する電極１２ｂを大地とする構造であったが、本実施形態では、大地と電気的に接続された金属製の容器Ｂを電極１２ｂとしたものである。
【００８１】
図１９（ａ）は平板状の絶縁構造物１５の凹部１７ａに電極１２ａを埋め込んで、電極１２ａの電極面と容器Ｂの壁面とを同一面とした例を示し、図１９（ｂ）は絶縁構造物１５に凹所２０を形成して、その凹所２０の底部に設けた凹部１７ａに電極１２ａを埋め込んだ例を示す。
【００８２】
これら例図で分かるように実施形態８と同様に絶縁構造物１５に設ける電極が１２ａの一つとなるため、絶縁構造物１５が小型となり、結果絶縁構造物１５を取り付けるために容器Ｂに設ける開口部１６の開口面積を小さくすることができ、容器Ｂの強度を弱めることはない。尚容量検知回路１３の一方の電極接続端には電極１２ａを、他方の電極接続端には容器Ｂを接続して、容量検知回路１３は容器Ｂたる電極１２ｂと、電極１２ａとの間の検知対象物による静電容量Ｃｘを検知し、出力部１４より静電容量Ｃｘの値に対応した例えば電圧信号を出力する。
（実施形態１０）
上記実施形態１乃至１０は電極１２ａ，１２ｂが検知対象物と直接接触する構造であったが、高温加熱されているものや、ｐＨ濃度が酸やアルカリを示している液体、石が含まれているセメント細骨材、また魚の骨などの固形物が含まれている生ゴミなどを検知対象物とする水分量センサでは、電極１２ａ、１２ｂが損傷する問題がある。
【００８３】
また、一対の電極１２ａ，１２ｂ間に電圧が印加されているため、ｐＨ濃度・温度・金属イオン化傾向の大小にも依存するが、基本的に電極の電気分解が発生して、溶解していく。
【００８４】
そこで腐食劣化防止のために、電極表面を数百μｍ程度の有機や向きの薄膜、例えば琺瑯などのコーティング処理が考えられるが、検知対象物が電極表面を移動していくようなオンライン計測では、膜の摩耗劣化が置き、膜の剥がれが発生する可能性は十分に考えられる。
【００８５】
そこで、本実施形態では、電極１２ａ、１２ｂに薄膜をコーティング処理により形成するのではなく、例えば図２０（ａ）に示すようなパターンの電極１２ａ、１２ｂを図２０（ｂ）に示すように絶縁構造物１５に設けた凹部１７ａ、１７ｂに夫々埋め込んで絶縁構造物１５の面と電極面とを同一面とし、更に図示するように数ｍｍの厚さの合成樹脂成形材料による絶縁物層２３を電極１２ａ、１２ｂを設けた絶縁構造物１５の面全体を覆うように設け、この絶縁物層２３の表面に検知対象物を接触するような構成としてある。図中Ｄは検知領域を示す。
【００８６】
ここで絶縁物層２３としてはポリプロピレン、ポリカーボネート、ポリフェニレンサルファイドなどを用いる。
【００８７】
図２１は本実施形態の水分量検知原理の回路構成を示しており、電極１２ａと、１２ｂとの間の静電容量は、絶縁物層２３による静電容量Ｃｓの分と、水分量による静電容量Ｃｘの分との合成容量からなり、両電極１２ａ、１２ｂに接続される容量検知回路１３はこれらの合成容量成分を検知し、この合成容量成分検知出力に基づいて出力部１４は静電容量Ｃｓの分を排除した形で、検知対象物の静電容量Ｃｘに対応する電気信号を出力する。
【００８８】
而して本実施形態によれば、絶縁物層２３の摩耗強度を適度に選択することにより、摩耗劣化が起こりにくく、更に数ｍｍの厚さのために電極１２ａ、１２ｂが露出してしまう可能性も少ない。
【００８９】
ところで、検知領域Ｄの奥行きの寸法は、電極１２ａ，１２ｂの端縁間の距離（間隔）に依存することは上述したとおりで、端縁間の距離に対して検知領域の奥行きの寸法は略１／２となる。例えば図２０（ａ）のようなパターンの電極１２ａ、１２ｂを用いた電極部１２において、図２２に示すように電極１２ａ、１２ｂの端縁間の距離が１６ｍｍの場合、検知領域Ｄの奥行き寸法は８ｍｍとなる。このとき電極１２ａ、１２ｂを覆う絶縁物層２３の厚みが１０ｍｍの場合、検知領域Ｄは絶縁物層２３内のみとなって、検知対象物の水分量の検知は不可能となる。
【００９０】
そこで、検知領域Ｄの奥行き寸法を決定する方法に従って、図２３（ａ）（ｂ）に示すように電極１２ａの一辺の長さをｄ０、電極１２ｂの幅をｄ１．両電極１２ａ，１２ｂ間の距離をｄ２、絶縁物層２３の厚さをｄ３としたとき、ｄ２／２＞ｄ３の関係に設定すれば、絶縁物層２３内に検知領域Ｄが存在しなくなる。つまり絶縁物層２３の厚みｄ３の２倍以上の距離ｄ２を離して両電極１２ａ、１２ｂを離して配置すればよい。
【００９１】
表３はこの絶縁物層２３の厚みｄ３と、距離ｄ２との関係を持たせて電極部１２を構成した例の各部の寸法を示す。
【００９２】
【表３】

【００９３】
【発明の効果】
請求項１の発明は、生ゴミ処理剤を検知対象物とし、この検知対象物に接する構造物の壁面より検知対象物側へ略突出しないように壁面に電極面を略並行させて配置した一対の電極からなる電極部と、該電極部の一対の電極で構成されるコンデンサ領域を検知領域とし、検知領域内に存在する水分量で決定される静電容量値を検知する容量検知回路と、容量検知回路から出力される検知された静電容量値に相当する値の電気量を出力する出力部とから成り、上記電極部の一対の電極端部の間の距離が上記検知領域内に存在する検知対象物以外の生ゴミの平均的な大きさの約２倍以上としたので、静電容量式による水分量を検知する水分量センサの特徴を生かせ、しかも残留堆積物の発生や流れの阻害が無く、製作コストの上昇の要因となる構造が不要な静電容量式水分量センサを提供でき、しかも検知対象物である生ゴミ処理剤以外の物質である生ゴミの影響を受けることなく正確に検知対象物の水分量を検知できるという効果がある。
【００９４】
請求項２の発明では、請求項１の発明において、上記電極部の一対の電極を略同一平面上に並設して成るので、請求項１の発明の効果に加えて、残留堆積物の発生や、流れの阻害を確実に無くすことができるという効果がある。
【００９６】
請求項３の発明では、請求項１記載の発明において、上記電極部の一対の電極の内の少なくとも一方の電極が、絶縁物を介して検知対象物に接するので、請求項１の発明の効果に加えて、少なくとも一方の電極の摩耗を防ぐことができるという効果がある。
【００９７】
請求項４の発明では、請求項３の発明において、上記電極部の一対の電極間の距離を上記絶縁物の厚さの倍以上として成るので、請求項４の発明の効果に加えて、水分量検知感度を低下させることなく、高精度に水分量検知ができるという効果がある。
【００９８】
請求項５の発明では、請求項１乃至４の何れかの発明において、上記電極部の一対の電極の内、上記容量検知回路の一方の電極接続端に接続される一方の電極の周囲を、上記容量検知回路の他方の電極接続端に接続される他方の電極が略囲むように配置したので、請求項１乃至５の何れの発明の効果に加えて、浮遊容量の影響を小さくして容量検知誤差の精度を高め、設計時の複雑さを解消することが可能であるという効果がある。
【００９９】
請求項６の発明では、請求項５の発明において、上記容量検知回路の上記他方の電極接続端に接続する電極を大地としたので、実際に設ける電極が一つとなるため、電極を取り付けるために構造物の壁にあける開口部を小さくすることができ、その結果構造物の強度を強めることができる静電容量式水分量センサを提供することにある。
【０１００】
請求項７の発明では、請求項５の発明において、電極材料となる金属からなる構造物体を、上記他方の電極としてあるので、請求項７の発明の効果に加えて、容量検知回路の電極接続端との接続が容易となるという効果がある。
【０１０１】
請求項８の発明では、請求項１乃至６の何れかの発明において、上記電極部の一対の電極の幅を略同一幅としてあるので、電極と構造物等の周囲の金属部位との間の浮遊容量を減少して浮遊容量の影響を減らすことができ、大地の電位などの変動や、漏れ電流による電位の変動に対しても、誤動作の少ないという効果がある。
【図面の簡単な説明】
【図１】（ａ）は本発明の実施形態１の電極部の配置部位の一部省略せる正面図である。（ｂ）は（ａ）のＸ−Ｘ’に対応する一部省略せる断面を示す構成図である。
【図２】同上の別の例の一部省略せる断面を示す構成図である。
【図３】（ａ）は同上の他の例の一部省略せる断面図である。
（ｂ）は同上のさらに別の例の一部省略せる断面図である。
【図４】（ａ）は本発明の実施形態２の電極部の配置部位の一部省略せる正面図である。（ｂ）は（ａ）のＸ−Ｘ’に対応する一部省略せる断面を示す構成図である。
【図５】同上の他の例の一部省略せる断面図である。
【図６】（ａ）は本発明の実施形態３の電極部の配置部位の一部省略せる正面図である。（ｂ）は（ａ）のＸ−Ｘ’に対応する一部省略せる断面を示す構成図である。
【図７】（ａ）〜（ｄ）は本発明の実施形態４の電極部の電極のパターン例の説明図である。
【図８】同上の別の電極部の電極のパターン例の説明図である。
【図９】（ａ）は同上の他の電極部の電極のパターン例の説明図である。
（ｂ）は同上のその他の電極部の電極のパターン例の説明図である。
【図１０】（ａ）は本発明の実施形態５の電極部の配置部位の一部省略せる正面図である。
（ｂ）は（ａ）のＸ−Ｘ’に対応する一部省略せる断面を示す構成図である。
【図１１】本発明の実施形態６の検知領域決定のための実験説明図である。
【図１２】同上の実験測定値のグラフである。
【図１３】（ａ）は同上の電極部の電極のパターン例の説明図である。
（ｂ）は同上の検知領域の説明図である。
【図１４】（ａ）は同上の電極のパターンの別例の説明図である。
（ｂ）は同上の検知領域の説明図である。
【図１５】（ａ）は本発明の実施形態７の前提となる浮遊容量の問題説明用の電極パターン例の説明図である。
（ｂ）は同上の浮遊容量の問題説明図である。
【図１６】（ａ）は同上の電極パターン例の説明図である。
（ｂ）は同上の浮遊容量の説明図である。
【図１７】同上の電極パターンの別例の説明図である。
【図１８】（ａ）は本発明の実施形態８の前提となる一例の容器の強度上の問題説明用の構成図である。
（ｂ）は本発明の実施形態８の前提となる別例の容器の強度上の問題説明用の構成図である。
【図１９】（ａ）は同上の一例の断面を示す構成図である。
（ｂ）は同上の別例の断面を示す構成図である。
【図２０】（ａ）は本発明の実施形態９の電極部の電極のパターン例図である。
（ｂ）は同上の電極部位の断面を示す構成図である。
【図２１】同上の電極等価回路構成図である。
【図２２】同上における検知領域の奥行き寸法と絶縁物層の厚さの問題説明図である。
【図２３】（ａ）は同上の検知領域の奥行き寸法と絶縁物層の厚さの関係説明用の電極部の電極のパターン例図である。
（ｂ）は同上の検知領域の奥行き寸法と絶縁物層の厚さの関係説明用の電極部位の断面を示す構成図である。
【図２４】静電容量式水分量センサにおける浮遊容量の影響を無くす電極部の構成説明図である。
【図２５】水分量センサと容器と検知対象物の関係説明図である。
【図２６】水の赤外光吸収特性の説明図である。
【図２７】従来例の構成図である。
【図２８】別の従来例の構成図である。
【図２９】他の従来例の構成図である。
【図３０】比誘電率とマイクロ波の周波数の関係の説明図である。
【図３１】その他の従来例の構成図である。
【図３２】静電容量式の水分量検知の原理説明図である。
【図３３】水分量と静電容量の関係の説明図である。
【図３４】静電容量式水分量センサの概略回路構成図である。
【図３５】（ａ）は静電容量式水分量センサの従来例の電極部の配置部位の一部省略せる正面図である。
（ｂ）は（ａ）のＸ−Ｘ’に対応する一部省略せる断面を示す構成図である。
【符号の説明】
Ａ 検知対象物
Ｂ 容器
１ 水分量センサ
１２ 電極部
１２ａ，１２ｂ 電極
１３ 容量検知回路
１４ 出力部
１５ 絶縁構造物
１６ 開口部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a capacitance type moisture sensor that detects the amount of moisture and the presence or absence of moisture.
[0002]
[Prior art]
Applications of moisture sensors include fermentation processes, rice grains, tea leaves, tobacco leaves, garbage, wood, soil, concrete fine aggregates, etc., each in a stationary or moving state. It is assumed that the amount of moisture contained in a substance is detected online or offline, or when rain detection, water level monitoring during bath hot water detection, or human body seating detection is performed.
[0003]
FIG. 25 shows the positional relationship between the object to be detected and the moisture sensor in these applications. As shown in this figure, the moisture amount sensor 1 is arranged outside the container B in which the detection object A is stored, and the moisture amount of the detection object A is detected.
[0004]
Depending on the water content detection principle of the water content sensor 1, it is necessary to provide an opening on the wall surface of the container B. The detection object A may be moved as indicated by an arrow or may be stationary.
[0005]
Conventionally, methods for measuring the amount of moisture are generally roughly classified into an infrared absorption type, a microwave type, an electric resistance type, a capacitance type, and a weight type.
[0006]
The infrared absorption formula utilizes the fact that a wavelength of 1.94 μm is well absorbed by water as can be seen from the infrared light absorption characteristics shown in FIG. 26, and an infrared wavelength near 1.94 μm, which is the water absorption wavelength. This is a method of irradiating a detection target with light and detecting the amount of moisture contained in the detection target from the amount of reflected light or transmitted light reduced with respect to the amount of irradiation light.
[0007]
FIG. 27 shows an example of this moisture absorption type moisture sensor. This moisture sensor 1 is arranged in the container B from the light source La through the wavelength switching filter 2, the half mirror 3 and the opening window W of the container B. The detection object A is irradiated with infrared light having a wavelength that water absorbs and a wavelength that water does not absorb by the wavelength switching filter 2, and each reflected infrared light is received by the wave receiver 4 and reflected. By detecting the powers P1 and P2 and using the ratio of the reflected powers P1 and P2 of both, a reflection type moisture sensor that detects the amount of moisture is constructed after removing the influence other than absorption by water. . Reference numeral 5 denotes a switching drive motor for the wavelength switching filter 2.
[0008]
The moisture amount sensor shown in FIG. 27 detects the moisture amount using the reflected power, but the moisture amount sensor 1 shown in FIG. 28 is opposite to the opening window W for allowing infrared light to enter the container B. An opening window W ′ for letting out infrared light transmitted through the detection target A to the outside of the container B is opened on the wall of the container B, and the transmission power of the transmitted infrared light is received corresponding to the opening window W ′. A wave receiver 4 is provided, and infrared light having a wavelength that is absorbed by water and infrared light having a wavelength that is not absorbed by water selected by the wavelength switching filter 2 are supplied to the detection object A in the container B. Irradiate and detect the transmission power P1 and P2 by the receiver 4, and use the ratio of the transmission power P1 and P2 of the two to detect the amount of water after removing the influence other than absorption by water. The transmission type moisture sensor is configured.
[0009]
The microwave method is a method of irradiating a detection target with a microwave of several GHz band and detecting the amount of water from the amount of reflection and transmission.
[0010]
When a few GHz band is used, the effect of the complex dielectric constant of water appears. That is, the imaginary part of the complex dielectric constant causes energy loss and propagation phase delay.
[0011]
For example, as shown in FIG. 29, the oscillator 7, the detector 8, and the microstrip circuit 9 constitute the moisture sensor 1, and the microstrip circuit 9 is provided on the wall surface of the container B so that the electric field is generated in the container B. The electric field is arranged so that the electric field passes through the inside of the detection target A in the container B. Then, since energy loss due to moisture occurs, the amount of loss is obtained from the power detected by the detector 8, and the amount of moisture is converted from this amount of loss.
[0012]
FIG. 30 shows the relationship between the relative dielectric constant, frequency, and complex dielectric constant.
[0013]
The dielectric constant characteristic of water can be expressed as ε = ε′−jε ″.
[0014]
The attenuation constant is
Attenuation constant (dB / m) = 27.3 / transmission wavelength × tan (δ)
ε ′ × tan (δ) = ε ″
It is expressed.
[0015]
(Reference: National Technical Report V.24 N.3 June 1978)
The electrical resistance method is a method of measuring the electrical resistance value between electrodes using the property that moisture is a conductor, and detecting the moisture content from the resistance value.
[0016]
That is, in this electric resistance type moisture amount sensor 1, a pair of electrodes 10a and 10b are arranged in a container B as shown in FIG. 31, and the electric resistance R due to the object A to be detected between the electrodes 10a and 10b is represented by a resistance bridge circuit. 6, the current flowing in accordance with the value of the electric resistance R is measured by the measuring instrument 11, the value of the electric resistance R is detected, and the moisture content is calculated by the following equation using the detected value of the electric resistance R: The amount of moisture is detected by calculating M.
[0017]
R = K / (M × M) × [1 + α (t−t0)]
R: electrical resistance value of detection object A, M moisture content, K: constant, α: temperature coefficient, t: standard temperature, t0: measurement temperature
When the detection target A is wood, it is generally several MΩ in a dry state and several kΩ in a state with much moisture. (Edited by Industrial Measurement Technology System Editorial Committee: Humidity and Moisture Measurement, see Nikkan Kogyo Shimbun 1965)
In FIG. 31, DC is a DC power source.
[0018]
In the capacitance type, using the property that water is a substance (dielectric) that polarizes, the capacitance value between the pair of electrodes 12a and 12b is measured as shown in FIG. This is a method for detecting the amount of moisture. Here, the amount of water is represented by the amount of water = water volume / (S × d), where S is the area of the electrode 12, d is the distance between the electrodes, and S × d is the volume of the detection area.
And the water content and capacitance Cx are
Cx = [ε ′ (water) × water content + ε ′ (other) × (1−water content)] × ε0 × S / d. Here, the relative dielectric constant ε ′ (water) of water is 80, and the relative dielectric constant ε ′ (others) is 1 in the case of 2 air in the case of wood, and the capacitance Cx depends on the amount of water in the detection region. Is determined. Although the value of the capacitance Cx also depends on the size of the electrodes 12a and 12b, it shows several pF in the dry state and several tens pF in the watery state. (See, for example, Industrial Measurement Technology System Editorial Committee: Humidity and Moisture Measurement published by Nikkan Kogyo Shimbun 1965)
FIG. 33 shows the relationship between the moisture content and the capacitance Cx. FIG. 34 shows a conceptual configuration of the capacitance-type moisture sensor 1, and the capacitance Cx at the electrode section 12 composed of the electrodes 12a and 12b corresponding to the moisture content of the detection object A is shown. A value is detected by the capacitance value detection circuit 13 and, for example, a voltage signal having an amount of electricity corresponding to the detected value of the capacitance Cx is output from the output unit 14.
[0019]
As defined in the JIS standard P-8127, the weight formula evaporates moisture by heating the object A to be detected in a drying furnace at 105 ° C. At this time, it is a method of obtaining the weight-to-weight ratio defined by a numerical value obtained by calculating the evaporated moisture mass from the mass before drying and the mass after drying and dividing by the mass before drying.
[0020]
[Problems to be solved by the invention]
By the way, in the moisture amount sensor 1 that uses transmitted light in the infrared absorption type, the detection target A must be made of a material that transmits infrared light. In this case, it is suitable for a thin paper or the like up to about several mm, but is not suitable for a material that does not transmit infrared light. Further, in the moisture amount sensor 1 using reflected light, the reflection condition is greatly influenced by the unevenness state and color of the surface of the detection target A. That is, there is a problem in that it is not possible to determine whether the amount of light reduction with respect to the amount of irradiation light is due to moisture absorption or reflection conditions, and it is not possible to accurately detect the amount of moisture.
[0021]
In addition, the microwave method measures the amount of propagation energy loss caused by the complex dielectric constant, which causes a problem that the apparatus becomes complicated and the manufacturing cost is high.
[0022]
In addition, the electrical resistance formula is a method of measuring resistance components using the electrical conductivity of water, but in reality impurities such as salt (NaCl) contained in moisture were formed by electrolysis. The ionic conductivity is orders of magnitude greater, so the value that can be measured by resistance is actually the concentration of impurities dissolved in moisture.
[0023]
Furthermore, the gravimetric method is not suitable for online measurement because of its measurement principle.
[0024]
On the other hand, the capacitance type causes an error if a dielectric constant equivalent to that of water is present, but the above-mentioned application (fermentation process / cereal grains such as rice, etc.) that does not contain an organic solvent substance having a relative dielectric constant of 20 to 50・ When detecting the amount of water contained in each substance on-line or off-line with tea leaves, tobacco leaves, garbage, wood, soil, concrete fine aggregate, etc. while each is stationary or moving In addition, since there is no substance with a relative dielectric constant equivalent to that of water among substances present in rain detection, water level monitoring during bath hot water detection, human body seating detection, etc., it is possible to detect the amount of moisture with little error. Although there is a feature that the amount of moisture in the detection object A can be brought into contact with the object A, an insulating structure is provided in the opening 16 on the inner wall of the container B as a structure as shown in FIGS. An object 15 is arranged and flat so that the electrode surfaces face each other. In the arranged electrodes 12a and 12b, the detection object A is buried between the electrodes 12a and 12b, and remains as a deposit. As a result, the moisture content of the deposit is measured, and the moisture of the detection object A is measured. There was a problem of not reflecting the amount. For this purpose, a cleaning structure is required so as not to remain deposited. However, in order to provide the cleaning structure, there has been a problem that the manufacturing cost is increased.
[0025]
In addition, the electrodes 12a and 12b protrude into the container B, so that the movement of the object A to be detected in the container B is hindered, a load is applied to the electrodes 12a and 12b, and deposits remain in other parts. There was a problem of doing. Therefore, it is necessary to give the structure of the electrodes 12a and 12b strong enough to withstand the load, resulting in a problem that the electrode structure becomes large and the manufacturing cost increases.
[0026]
In FIG. 35 (b), Cx represents electrostatic capacitance due to the detection object, and C1, C2, and Cc represent stray capacitance.
[0027]
The present invention has been made in view of the above-mentioned problems, and its object is to make use of the characteristics of a moisture sensor that detects the amount of moisture by a capacitance type, and to generate and flow residual deposits. There is no obstruction, and there is no need for a structure that increases production costs. Therefore, it is possible to accurately detect the moisture content of the detection target without being affected by garbage other than the garbage treatment agent that is the detection target. The object is to provide a capacitive moisture sensor.
[0028]
In addition to the object of the invention of claim 1, an object of the invention of claim 2 is to provide a capacitance type moisture sensor capable of reliably eliminating the generation of residual deposits and obstruction of the flow. .
[0030]
Claim 3 In addition to the object of the invention of claim 1, an object of the invention is to provide a capacitance type moisture sensor capable of preventing wear of at least one of the electrodes.
[0031]
Claim 4 The purpose of the invention is to claim 3 In addition to the object of the present invention, it is an object of the present invention to provide a capacitive moisture sensor that can detect moisture with high accuracy without lowering the moisture detection sensitivity.
[0032]
Claim 5 The object of the present invention is as follows. 4 In addition to any of the objects of the invention, it is an object of the present invention to provide a capacitance type moisture sensor that increases the accuracy of capacitance detection error and eliminates the complexity of design.
[0033]
Claim 6 The purpose of the invention is to claim 5 In addition to the object of the present invention, it is an object of the present invention to provide a capacitance type moisture sensor capable of increasing the strength of a structure by using one of the electrodes as the ground.
[0034]
Claim 7 The purpose of the invention is to claim 6 In addition to the object of the present invention, it is an object of the present invention to provide a capacitive moisture sensor in which the connection between the capacitance detection circuit and the electrode serving as the earth is easy.
[0035]
Claim 8 The object of the present invention is as follows. 6 In addition to the object of any one of the inventions, it is an object to provide a capacitance type moisture sensor with few malfunctions even with respect to fluctuations in ground potential or the like, or fluctuations in potential due to leakage current.
[0036]
[Means for Solving the Problems]
In order to achieve the above object, in the invention of claim 1, Use garbage treatment agent as the object to be detected. It consists of an electrode part consisting of a pair of electrodes arranged in parallel with the electrode surface on the wall surface so as not to protrude substantially toward the detection object side from the wall surface of the structure in contact with the detection object, and a pair of electrodes of the electrode part A capacitance detection circuit that detects a capacitance value determined by the amount of moisture present in the detection region, and a value corresponding to the detected capacitance value output from the capacitance detection circuit An output unit that outputs the amount of electricity The distance between the pair of electrode end portions of the electrode portion is at least about twice the average size of garbage other than the detection target existing in the detection region It is characterized by comprising.
[0037]
According to a second aspect of the present invention, in the first aspect of the invention, the pair of electrodes of the electrode portion are arranged side by side on substantially the same plane.
[0039]
Claim 3 The invention according to claim 1 is characterized in that, in the invention according to claim 1, at least one of the pair of electrodes of the electrode portion is in contact with the object to be detected through an insulator.
[0040]
Claim 4 In the invention of claim 3 In the invention, the distance between the pair of electrodes of the electrode portion is set to be not less than twice the thickness of the insulator.
[0041]
Claim 5 In the present invention, claims 1 to 4 In any one of the inventions, the periphery of one electrode connected to one electrode connection end of the capacitance detection circuit of the pair of electrodes of the electrode portion is connected to the other electrode connection end of the capacitance detection circuit. The other electrode is arranged so as to substantially surround.
[0042]
Claim 6 In the invention of claim 5 In the invention, the electrode connected to the other electrode connection end of the capacitance detection circuit is a ground.
[0043]
Claim 7 In the invention of claim 6 In the invention, the electrode connected to the other electrode connection end of the capacitance detection circuit is the metal structure connected to the ground.
[0044]
Claim 8 In the present invention, claims 1 to 6 In any one of the inventions, the width of the pair of electrodes of the electrode portion is substantially the same.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described with reference to embodiments. Since the circuit configuration and detection principle of the present invention are those shown in FIGS. 32 to 34, the description of the circuit configuration and detection principle is omitted.
(Embodiment 1)
FIGS. 1A and 1B show the main part of the electrode part 12 of the moisture sensor 1 of the present embodiment, and a synthetic resin is formed in the opening 16 formed on the wall surface of the container B containing the detection object A. An insulating structure 15 formed of a molding material or a ceramic material is fitted into a part of the wall surface of the container B, and a strip-shaped electrode 12a constituting the electrode portion 12 on the side surface of the container B of the insulating structure 15; Strip-shaped electrodes 12b and 12b narrower than the electrode 12a are arranged on both sides of the electrode 12a, the center electrode 12a is connected to one electrode connection end of the capacitance detection circuit 13, and the electrodes 12b and 12b on both sides are capacitance-detected. A capacitor formed by connecting to the other electrode connection end of the circuit 13 to form a pair of electrodes with the electrode 12a and the electrodes 12b and 12b, and between the pair of electrodes 12a and the electrodes 12b and 12b. Capacitance of inspection object A in the area Is the detection region.
[0046]
Thus, according to the moisture sensor 1 of the present embodiment, the contact between the inspection object A moving in the container B and the electrode unit 12 causes the electrode 12a, 12b between the electrodes 12a and 12b corresponding to the moisture content in the inspection object A. The capacitance detection circuit 13 detects the value of the capacitance Cx, and outputs, for example, a voltage signal corresponding to the detected value of the capacitance Cx from the output unit 14. An electrostatic capacity type moisture sensor that can detect the moisture content can be realized. In particular, in the present embodiment, since the electrode surfaces of the electrodes 12a, 12b, and 12b are parallel to and substantially on the same surface as the wall surface of the container B, the movement of the inspection object A in the container B is caused by the electrodes 12a and 12b. 12b does not obstruct, so that it is not necessary to increase the strength of the electrode structure, hardly deposit between the electrodes 12a, 12b, no cleaning means for cleaning the deposit is required, and the manufacturing cost is low. A capacitive moisture sensor can be provided.
[0047]
As shown in FIG. 2, recesses 17a, 17b, 17b that are recessed outward are formed in the insulating structure 15, and the electrodes 12a, 12b, 12b are embedded in the recesses 17a, 17b, 17b. The electrode surface 12b may be the same surface as the surface of the insulating structure 15, that is, the wall surface of the container B. Since the thickness of the electrodes 12a and 12b does not protrude into the container B, there is no deposit between the electrodes 12a and 12b.
[0048]
In FIG. 2, the capacitance detection circuit and the output unit are not shown, but it goes without saying that they are provided in the same manner as in FIG.
[0049]
When fixing the insulating structure 15 to the container B, as shown in FIG. 3A, the thickness of the insulating structure 15 is made thicker than the thickness of the wall portion of the container B, and the outer wall of the container B is formed from both ends thereof. A method in which the fixing pieces 15a to be overlapped are formed in a projecting manner, and the fixing pieces 15a and the outer wall surface of the container B are bonded and fixed, or a method in which the fixing screws 15a and the nuts 19 are used to fix the screws as shown in FIG. Should be adopted. 3A and 3B is the electrode arrangement structure of FIG. 2, of course, these fixing methods may be adopted in the example of the electrode arrangement structure of FIG. Of course, these fixing methods may be adopted for fixing the insulating structure 15 of each embodiment to be described later to the container B. Therefore, the fixing method is not particularly referred to hereinafter.
[0050]
(Embodiment 2)
In the first embodiment, the electrodes 12a, 12b, and 12b are arranged so as to be substantially flush with the surface of the insulating structure 15, that is, the wall surface of the container B. As shown in (b), the surface side of the insulating structure 15 in contact with the object A to be detected is opened and a recess 20 having a trapezoidal cross-sectional shape is provided, and recesses 17a provided on gentle slopes on both sides of the recess 20; The pair of electrodes 12a and 12b constituting the electrode portion 12 is embedded in 17b, and does not protrude into the container B, and has a structure substantially parallel to the wall surface of the container B. FIG. 5 shows an example in which the electrodes 12a and 12b are provided on the surface of the gentle slope of the insulating structure 15.
[0051]
Also in this embodiment, since the electrode surfaces of the electrodes 12a and 12b are substantially parallel to and on the same plane as the wall surface of the container B, the electrodes 12a, 12b and 12b hinder the movement of the inspection object A in the container B. Therefore, there is no need to increase the strength of the electrode structure, there is almost no deposition between the electrodes 12a and 12b, no cleaning means for cleaning the deposits is required, and the capacitance type is inexpensive in manufacturing cost. A moisture sensor can be provided.
[0052]
In FIG. 4, Cx indicates the capacitance between the electrodes 12a and 12b due to the detection object A. C1 and Cc are stray capacitances between the electrodes 12a and 12b and the metal container B, and C2 is a stray capacitance between the capacitance detection circuit 13 and the ground.
[0053]
(Embodiment 3)
In the second embodiment, one electrode 12a, 12b is arranged on the gentle slope of the recess 20 of the insulating structure 15 to constitute the electrode portion 12, but this embodiment is shown in FIG. As shown in b), the electrode section 12 is configured by using one electrode 12a and two electrodes 12b and 12b in the same manner as in the first embodiment. A wide electrode is formed in the recess 17a at the bottom of the recess 20. The electrode 12a is embedded in the concave portions 17b of the gentle slopes on both sides.
[0054]
Since the electrode surfaces of the electrodes 12a and 12b are substantially parallel to the wall surface of the container B and are substantially on the same plane as in the second embodiment, the inspection object A moves in the container B in the electrode 12a, 12b and 12b do not get in the way, so there is no need to increase the strength of the electrode structure, and there is almost no accumulation between the electrodes 12a and 12b, and no cleaning means for cleaning the deposit is required, resulting in a low manufacturing cost. An inexpensive capacitive moisture sensor can be provided.
[0055]
By the way, in this embodiment, since the electrodes 12b and 12b are arranged on both sides so as to surround the center electrode 12a, the electric lines of force between the center electrode 12a and the electrodes 12b and 12b on both sides exist symmetrically. It will be. Since the electrode 12b connected to the other electrode connection end of the capacitance detection circuit 13 exists outside the electrode 12a connected to one electrode connection end of the capacitance detection circuit 13, one electrode connection end of the capacitance detection circuit 13 The amount of leakage of the electric lines of force to the outside of the stray capacitance generated from the electrode 12a connected to the electrode can be reduced. That is, the influence of the stray capacitance Cc between the electrode 12a and the container B shown in FIG.
[0056]
As a result, in the present embodiment, it is possible to accurately detect the amount of water without being affected by stray capacitance.
[0057]
In the case of the first embodiment described above, it is needless to say that the influence of the stray capacitance can be reduced because the electrodes 12b and 12b are arranged on both sides of the central electrode 12a.
[0058]
Further, in order to eliminate the problem of stray capacitance in the electrode portion having the structure in which the electrodes are erected as shown in FIG. 35, the electrode 12a connected to one electrode connection end of the capacitance detection circuit 13 as shown in FIG. Is arranged so as to be substantially flush with the surface of the insulating structure 15, and electrodes 12b and 12b connected to the other electrode connection ends of the capacitance detection circuit 13 are vertically suspended on both sides thereof, as in the present embodiment. Stray capacitance can be reduced.
(Embodiment 4)
Although the electrodes 12a and 12b of the electrode portions of the first to third embodiments are configured by arranging strips in parallel, the periphery of the electrode 12a is formed as shown in FIGS. An annular electrode 12b may be disposed so as to surround the electrode portion 12 with the electrodes 12a and 12b. When these electrodes 12a and 12b are disposed in the above-described insulating structure 15, they are disposed on the surface on the inspection object A side as in the first to third embodiments described above, or a recessed portion is provided and embedded. Just set up.
[0059]
When the central electrode 12a is connected to the electrode connection end of the capacitance detection circuit 13, an electric circuit or the like penetrating the insulating structure 15 may be used, but a part of the annular electrode 12b is cut as shown in FIG. You may make it pull out the connection electric circuit 22 from the notch 21 without it.
[0060]
7 and 8 show the patterns of the electrodes 12a and 12b corresponding to the flat insulating structure 15, but FIGS. 9A and 9B are provided with a recess 20 in the insulating structure 15. An example in which the annular electrode 12b is arranged on the gentle slope around the place 20 and the electrode 12a is arranged in the center of the recess 20 is shown.
[0061]
In each example of the present embodiment, the electrode 12b is provided so as to surround the central electrode 12a, so that it is not easily affected by the stray capacitance as in the first and third embodiments.
(Embodiment 5)
In the first to third embodiments or 4 described above, the wall surface of the container B is a flat surface, and the flat insulating structure 15 corresponding to this is used. However, as shown in FIG. Is a curved surface, the insulating structure 15 having a curved surface is used so as to be flush with the wall surface, and the electrodes 12a and 12b curved so as to form the same surface as the curved surface of the insulating structure 15 are used. .
[0062]
In the case of the present embodiment, as shown in FIG. 10 (a), the electrode portion 12 is constituted by the annular electrode 12b so as to surround the square electrode 12a as in FIG. 7 (a), and these electrodes 12a. , 12b, electrodes 12a, 12b corresponding to the recesses 17a, 17b formed on the surface of the insulating structure 15 in accordance with the shape of the insulating structure 15 are embedded to constitute the electrode portion 12, and one electrode 12a is one electrode of the capacitance detection circuit 13. The other electrode 12b is connected to the other electrode connection end of the capacitance detection circuit 13 at the connection end.
[0063]
In this embodiment, as in the second embodiment, the electrode surfaces of the electrodes 12a and 12b are provided substantially in parallel with the wall surface of the container B and on the same surface, so that the inspection object A moves within the container B. 12a and 12b do not obstruct, so there is no need to increase the strength of the electrode structure, there is almost no deposition between the electrodes 12a and 12b, no cleaning means for cleaning the deposit is required, and the manufacturing cost is low. Can provide a capacitive water content sensor.
(Embodiment 6)
By the way, when the capacitance-type moisture sensor of the present invention is used for, for example, a moisture sensor for measuring the moisture content of a garbage treatment agent infested with microorganisms, the garbage is actually disposed inside the garbage treatment tank. Along with the treatment agent, there is also garbage itself. And when the component which comprises a garbage is measured, as shown in Table 1, there is much moisture. Table 1 shows the amount of moisture contained in the garbage that is assumed when the moisture sensor 1 is attached to a bio-type garbage disposal machine in weight%.
[0064]
The amount of water in the garbage treatment agent, which is the detection target, is about 60% at the maximum by weight%, and is generally on the dry side. Even if the detection target has such a moisture content, if the garbage itself occupies a detection area formed between the electrodes 12a and 12b, the moisture sensor outputs a detection output corresponding to the moisture content of the garbage. As a result, it is impossible to measure the water content of the raw garbage treatment agent that is originally required.
[0065]
[Table 1]

[0066]
By the way, the general size of garbage is pulverized immediately after being put into the garbage processing machine to the size shown in Table 2. Table 2 shows actual measurement values obtained by determining the ratio of the remaining garbage by actually screening the garbage with various eye sizes.
[0067]
It can be seen from Table 2 that garbage is crushed to a size of about 15 mm. Therefore, it was found that if the detection area has a margin and is about 20 mm or more, the detection area is not filled with garbage.
[0068]
[Table 2]

[0069]
Therefore, the present inventors obtained the relationship between the size and distance of the pair of electrodes 12a and 12b that determine the detection region and the detection region using the experimental electrode unit shown in FIG.
[0070]
In this experiment, the electrode width W of a pair of strip-shaped electrodes 12a and 12b made of a copper foil tape having a thickness of 0.1 mm and a length of 115 mm is 24 mm, and the distance P between the electrodes 12a and 12b is 2 mm. The electrode width W of the pair of strip-shaped electrodes 12a and 12b made of the same copper foil tape as described above is 10 mm, and the distance P between the electrodes 12a and 12b is 30 mm. One electrode width W of a pair of strips of electrodes 12a, 12b made of a copper foil tape having the same thickness and length as described above is 5 mm, the other electrode width W is 25 mm, A box-like shape having a square bottom surface with a thickness of 1 mm and a side length of 115 mm, and a height of 40 mm, using an electrode portion having an electrode configuration in which the distance P between the electrodes 12a and 12b is 20 mm. Each electrode on the outer bottom of the non-conductive resin case PC 2a and 12b were adhered, water was poured into the resin case PC, and when the water level at this time was increased to 5 mm, 10 mm, 25 mm,... The interelectrode capacitance was as shown in FIG. In FIG. 12, the electrode width of the electrodes 12a and 12b is 24 mm, and the distance between the electrodes 12a and 12b is 2 mm. As a result of measuring the interelectrode capacitance of the electrode portion having the electrode configuration of 10 mm and the distance between the electrodes 12a and 12b being 30 mm, the electrode width of one of the electrodes 12a and 12b is 5 mm and the other electrode width is 25 mm. The measurement result of the capacity | capacitance between electrodes of the electrode part of the electrode structure whose distance between electrodes 12a and 12b is 20 mm is shown.
[0071]
From this result, when the water level at which the interelectrode capacitance does not change even if the water level is increased is defined as the detection region D in the depth direction from the electrode surface, the depth dimension of the detection region D is parallel to and far from the electrodes 12a and 12b. It was found to be about half of the distance between the edges, ie the total width (50 mm).
[0072]
Thus, by constructing a moisture sensor that detects the moisture content of the garbage treatment agent that is the target for detecting the moisture content of the garbage disposal machine that satisfies the above-described conditions, the It became possible to detect the amount of moisture.
[0073]
FIG. 13 (a) shows an example of the electrode part 12 of this embodiment. This example corresponds to the electrode shape of FIG. 7 (a). The dimension of one side of the central electrode 12a is d0, A detection area D determined by the size of the pair of electrodes 12a and 12b, where the width dimension of the electrode 12b is d1, and the dimension between the side of the electrode 12a and the inner side of the electrode 12b opposite to the electrode 12b is d2. In order to satisfy a depth dimension of 20 mm or more, which is the above condition, the present inventors based on experimental results, between the edges that are far from each other among the parallel edges of the electrodes 12a and 12b. As shown in FIG. 13B, the width dimension and the interval of the electrodes 12a and 12b are set so that the distance (= d1 + d2 + d0) is not less than double (L) of the depth dimension 20 mm (L / 2) of the detection region D.
[0074]
14A and 14B show an example in which the electrode portion 12 is configured with an annular electrode 12b having an inner diameter of (d2 × 2) + d0 and a width of d1 with respect to a circular electrode 12a having a diameter of d0 (FIG. 14). In this example, the distance (d1 + d2 + d0) between the far ends of the parallel edges of the electrodes 12a and 12b is the depth dimension 20 mm (L / 2) of the detection region D. The width dimension and interval of the electrodes 12a and 12b are set so as to be at least twice (L).
[0075]
(Embodiment 7)
By the way, when the electrode 12 is composed of a square electrode 12a and a square frame-shaped electrode 12b arranged so as to surround the electrode 12a as shown in FIGS. 15 (a) and 15 (b), for example, When the dimension d0 of one side of the square is set to be larger than the width d1 of the surrounding electrode 12b, stray capacitance (a thin line arrow indicates electric lines of force) is generated between the electrodes 12a and 12b, and the electrode 12a A stray capacitance (a thick solid arrow indicates a line of electric force) is generated between the ground and the ground. A malfunction occurs when the potential of the parasitic destination of the stray capacitance fluctuates, for example, the ground potential fluctuates. In particular, when the container B is made of metal, it is not certain what electrical behavior is exhibited, such as leakage current of other electronic components. Therefore, it is safer to reduce the stray capacitance as much as possible.
[0076]
In this embodiment, as shown in FIGS. 16A, 16B, or 17, a square or circular electrode 12a embedded in the recesses 17a, 17b so as to be flush with the surface of the insulating structure 15. When the length or diameter of one side, that is, the width is d0, the width d1 of the surrounding electrode 12b is the same (d1 = d0). In the figure, d2 indicates the distance between the electrodes 12a and 12b.
[0077]
Therefore, in the configuration of the present embodiment, the density of the electric lines of force is the same between the electrodes 12a and 12b, so that the stray capacitance is reduced. As a result, malfunction occurs even when the potential of the ground is changed or the potential is changed due to the leakage current. It is possible to realize a moisture amount sensor with a small amount.
(Embodiment 8)
In the first to seventh embodiments, the electrode portion 12 including the electrodes 12a and 12b is provided in the insulating structure 15, and the insulating structure 15 is attached to the opening 16 provided in the container B. , 12b are provided in the insulating structure 15, so that the insulating structure 15 increases in size, and therefore the opening 16 becomes larger. As a result, the strength of the container B may be reduced.
[0078]
Therefore, in the present embodiment, the electrode 12a connected to one electrode connection end of the capacitance detection circuit 13 is left as it is, but the electrode 12b connected to the other electrode connection end is configured by the ground.
[0079]
FIG. 18A shows an example in which the electrode 12a is embedded in the recess 17a of the flat insulating structure 15, and the electrode surface of the electrode 12a and the wall surface of the container B are the same surface, and FIG. An example in which the recess 20 is formed in the structure 15 and the electrode 12a is embedded in the recess 17a provided at the bottom of the recess 20 is shown.
[0080]
As can be seen from these example drawings, since the electrode provided on the insulating structure 15 is one of 12a, the insulating structure 15 is reduced in size, and as a result, the opening area of the opening 16 provided in the container B for attaching the insulating structure 15 is reduced. It can be made smaller and does not weaken the strength of the container B. The electrode 12a is connected to one electrode connection end of the capacitance detection circuit 13, and the ground is connected to the other electrode connection end. The capacitance detection circuit 13 depends on the detection object between the ground electrode 12b and the electrode 12a. The value of the capacitance Cx is detected, and for example, a voltage signal corresponding to the value of the capacitance Cx is output from the output unit 14.
(Embodiment 9)
Embodiment 8 has a structure in which the electrode 12b connected to the other electrode connection end of the capacitance detection circuit 13 is grounded, but in this embodiment, a metal container B electrically connected to the ground is provided. This is an electrode 12b.
[0081]
FIG. 19A shows an example in which the electrode 12a is embedded in the concave portion 17a of the flat insulating structure 15 so that the electrode surface of the electrode 12a and the wall surface of the container B are the same surface, and FIG. An example in which the recess 20 is formed in the structure 15 and the electrode 12a is embedded in the recess 17a provided at the bottom of the recess 20 is shown.
[0082]
As can be seen from these example diagrams, the electrode provided on the insulating structure 15 is one of 12a as in the eighth embodiment, so that the insulating structure 15 becomes small, and as a result, the opening provided in the container B for attaching the insulating structure 15 The opening area of the portion 16 can be reduced, and the strength of the container B is not weakened. The electrode 12a is connected to one electrode connection end of the capacitance detection circuit 13, and the container B is connected to the other electrode connection end. The capacitance detection circuit 13 detects between the electrode 12b as the container B and the electrode 12a. The electrostatic capacitance Cx due to the object is detected, and for example, a voltage signal corresponding to the value of the electrostatic capacitance Cx is output from the output unit 14.
(Embodiment 10)
Embodiments 1 to 10 described above have a structure in which the electrodes 12a and 12b are in direct contact with the object to be detected, but include those heated at high temperature, liquids and stones whose pH concentration indicates acid or alkali, and the like. In a moisture sensor that uses a cement fine aggregate or raw garbage containing solid matter such as fish bone as a detection target, there is a problem that the electrodes 12a and 12b are damaged.
[0083]
In addition, since a voltage is applied between the pair of electrodes 12a and 12b, the electrode basically undergoes electrolysis and dissolves depending on the pH concentration, temperature, and metal ionization tendency. .
[0084]
Therefore, in order to prevent corrosion degradation, the electrode surface can be coated with organic or oriented thin film of about several hundred μm, such as wrinkles, but in online measurement where the detection target moves on the electrode surface, There is a possibility that the film will be worn away and the film may be peeled off.
[0085]
Therefore, in this embodiment, instead of forming a thin film on the electrodes 12a and 12b by coating, for example, the electrodes 12a and 12b having a pattern as shown in FIG. 20A are insulated as shown in FIG. The surface of the insulating structure 15 and the electrode surface are made to be the same surface by being embedded in the recesses 17a and 17b provided in the structure 15, respectively, and an insulating layer 23 made of a synthetic resin molding material having a thickness of several millimeters as shown in the figure. The insulating structure 15 provided with the electrodes 12 a and 12 b is provided so as to cover the entire surface, and the detection target is brought into contact with the surface of the insulating layer 23. In the figure, D indicates a detection area.
[0086]
Here, as the insulating layer 23, polypropylene, polycarbonate, polyphenylene sulfide, or the like is used.
[0087]
FIG. 21 shows a circuit configuration of the moisture amount detection principle of the present embodiment. The capacitance between the electrodes 12a and 12b is the amount of the capacitance Cs due to the insulator layer 23 and the static amount due to the moisture amount. The capacitance detection circuit 13 connected to both electrodes 12a and 12b detects these combined capacitance components, and the output unit 14 is electrostatically based on the combined capacitance component detection output. An electric signal corresponding to the capacitance Cx of the detection target is output in a form that excludes the capacitance Cs.
[0088]
Thus, according to the present embodiment, by appropriately selecting the wear strength of the insulator layer 23, wear deterioration is unlikely to occur, and the electrodes 12a and 12b may be exposed due to the thickness of several millimeters. There is little nature.
[0089]
By the way, as described above, the depth dimension of the detection region D depends on the distance (interval) between the edges of the electrodes 12a and 12b, and the depth dimension of the detection region is approximately the distance between the edges. 1/2. For example, in the electrode part 12 using the electrodes 12a and 12b having a pattern as shown in FIG. 20A, when the distance between the edges of the electrodes 12a and 12b is 16 mm as shown in FIG. Is 8 mm. At this time, when the thickness of the insulating layer 23 covering the electrodes 12a and 12b is 10 mm, the detection region D is only in the insulating layer 23, and the moisture content of the detection target cannot be detected.
[0090]
Therefore, according to the method of determining the depth dimension of the detection region D, as shown in FIGS. 23A and 23B, the length of one side of the electrode 12a is d0, and the width of the electrode 12b is d1. When the distance between the electrodes 12a and 12b is d2 and the thickness of the insulator layer 23 is d3, the detection region D does not exist in the insulator layer 23 if the relationship d2 / 2> d3 is set. In other words, the electrodes 12a and 12b may be spaced apart by a distance d2 that is twice or more the thickness d3 of the insulator layer 23.
[0091]
Table 3 shows the dimensions of each part of the example in which the electrode part 12 is configured with the relationship between the thickness d3 of the insulator layer 23 and the distance d2.
[0092]
[Table 3]

[0093]
【The invention's effect】
The invention of claim 1 Use garbage treatment agent as the object to be detected. It consists of an electrode part consisting of a pair of electrodes arranged in parallel with the electrode surface on the wall surface so as not to protrude substantially from the wall surface of the structure in contact with the detection object to the detection object side, and a pair of electrodes of the electrode part. A capacitance detection circuit that detects a capacitance value determined by the amount of moisture present in the detection region, and a value corresponding to the detected capacitance value output from the capacitance detection circuit An output unit that outputs the amount of electricity Since the distance between the pair of electrode ends of the electrode portion is about twice or more the average size of garbage other than the detection target existing in the detection region, Capacitance-type moisture sensor that makes use of the features of the moisture-type sensor that detects the amount of moisture by the capacitance type, and does not obstruct the generation of residual deposits or flow, and does not require a structure that increases production costs. Can provide In addition, it is possible to accurately detect the amount of moisture in the detection target without being affected by garbage other than the garbage treatment agent that is the detection target. There is an effect that.
[0094]
According to a second aspect of the invention, in the first aspect of the invention, the pair of electrodes of the electrode portion are arranged side by side on substantially the same plane. Therefore, in addition to the effects of the first aspect of the invention, the generation of residual deposits In addition, there is an effect that the obstruction of the flow can be surely eliminated.
[0096]
Claim 3 In the invention of claim 1, in addition to the effect of the invention of claim 1, since at least one of the pair of electrodes of the electrode part contacts the object to be detected through an insulator. There is an effect that wear of at least one of the electrodes can be prevented.
[0097]
Claim 4 In the invention of claim 3 In the invention, since the distance between the pair of electrodes of the electrode part is not less than twice the thickness of the insulator, in addition to the effect of the invention of claim 4, it is possible to increase the water content detection sensitivity without deteriorating. There is an effect that the moisture amount can be detected with high accuracy.
[0098]
Claim 5 In the present invention, claims 1 to 4 In any one of the inventions, the periphery of one electrode connected to one electrode connection end of the capacitance detection circuit of the pair of electrodes of the electrode portion is connected to the other electrode connection end of the capacitance detection circuit. In addition to the effect of any one of the first to fifth aspects, the influence of the stray capacitance is reduced to increase the accuracy of capacitance detection error, and the design complexity is increased. It is possible to eliminate the problem.
[0099]
Claim 6 In the invention of claim 5 In this invention, since the electrode connected to the other electrode connection end of the capacitance detection circuit is grounded, only one electrode is actually provided. Therefore, the opening on the wall of the structure for attaching the electrode is made small. Accordingly, an object of the present invention is to provide a capacitance type moisture sensor that can increase the strength of a structure.
[0100]
Claim 7 In the invention of claim 5 In this invention, since the structure object made of the metal as the electrode material is used as the other electrode, in addition to the effect of the invention of claim 7, the effect of facilitating connection with the electrode connection end of the capacitance detection circuit There is.
[0101]
Claim 8 In the present invention, claims 1 to 6 In any of the inventions, since the width of the pair of electrodes of the electrode portion is substantially the same width, the stray capacitance between the electrode and a surrounding metal part such as a structure is reduced to reduce the influence of the stray capacitance. Therefore, there is an effect that there are few malfunctions even with respect to fluctuations in ground potential and the like, and fluctuations in potential due to leakage current.
[Brief description of the drawings]
FIG. 1A is a front view in which a part of an electrode portion arrangement portion according to Embodiment 1 of the present invention can be omitted. (B) is a block diagram which shows the cross section which can be abbreviate | omitted corresponding to XX 'of (a).
FIG. 2 is a configuration diagram showing a cross-section that can be partially omitted in another example of the above.
FIG. 3A is a cross-sectional view in which another example of the above is partially omitted.
(B) is sectional drawing which a part of another example same as the above can omit.
FIG. 4 (a) is a front view in which a part of an electrode part arrangement portion according to Embodiment 2 of the present invention can be omitted. (B) is a block diagram which shows the cross section which can be abbreviate | omitted corresponding to XX 'of (a).
FIG. 5 is a cross-sectional view in which another example of the above is partially omitted.
FIG. 6 (a) is a front view in which a part of an electrode part arrangement portion according to Embodiment 3 of the present invention can be omitted. (B) is a block diagram which shows the cross section which can be abbreviate | omitted corresponding to XX 'of (a).
FIGS. 7A to 7D are explanatory diagrams of electrode pattern examples of an electrode unit according to the fourth embodiment of the present invention. FIGS.
FIG. 8 is an explanatory diagram of an electrode pattern example of another electrode unit of the above.
FIG. 9A is an explanatory diagram of an example of an electrode pattern of another electrode unit of the above.
(B) is explanatory drawing of the example of a pattern of the electrode of the other electrode part same as the above.
FIG. 10 (a) is a front view in which a part of the arrangement part of the electrode part according to the fifth embodiment of the present invention can be omitted.
(B) is a block diagram which shows the cross section which can be abbreviate | omitted corresponding to XX 'of (a).
FIG. 11 is an explanatory diagram of an experiment for determining a detection area according to the sixth embodiment of the present invention.
FIG. 12 is a graph of experimental measurement values as described above.
FIG. 13A is an explanatory diagram of an electrode pattern example of the electrode portion of the above.
(B) is explanatory drawing of a detection area same as the above.
FIG. 14A is an explanatory diagram of another example of the electrode pattern of the above.
(B) is explanatory drawing of a detection area same as the above.
FIG. 15A is an explanatory diagram of an example of an electrode pattern for explaining a problem of stray capacitance, which is a premise of the seventh embodiment of the present invention.
(B) is a problem explanatory diagram of the stray capacitance described above.
FIG. 16A is an explanatory diagram of an example of the electrode pattern of the above.
(B) is an explanatory view of the above stray capacitance.
FIG. 17 is an explanatory diagram of another example of the electrode pattern same as above.
FIG. 18A is a configuration diagram for explaining a problem in strength of an example container which is a premise of an eighth embodiment of the present invention.
(B) is a block diagram for demonstrating the problem on the intensity | strength of the container of another example used as the premise of Embodiment 8 of this invention.
FIG. 19A is a configuration diagram showing a cross section of an example of the above.
(B) is a block diagram which shows the cross section of another example same as the above.
FIG. 20 (a) is a diagram showing an example of an electrode pattern of an electrode unit according to the ninth embodiment of the present invention.
(B) is a block diagram which shows the cross section of an electrode part same as the above.
FIG. 21 is an electrode equivalent circuit configuration diagram of the above.
FIG. 22 is a diagram for explaining the problem of the depth size of the detection region and the thickness of the insulating layer in the same as above.
FIG. 23A is an electrode pattern diagram of an electrode portion for explaining the relationship between the depth dimension of the detection region and the thickness of the insulating layer.
(B) is a block diagram which shows the cross section of the electrode site | part for description of the relationship between the depth dimension of a detection region same as the above, and the thickness of an insulator layer.
FIG. 24 is a diagram illustrating the configuration of an electrode unit that eliminates the influence of stray capacitance in a capacitive moisture sensor.
FIG. 25 is an explanatory diagram of the relationship among a moisture sensor, a container, and a detection object.
FIG. 26 is an explanatory diagram of the infrared light absorption characteristics of water.
FIG. 27 is a configuration diagram of a conventional example.
FIG. 28 is a configuration diagram of another conventional example.
FIG. 29 is a configuration diagram of another conventional example.
FIG. 30 is an explanatory diagram of a relationship between a relative dielectric constant and a microwave frequency.
FIG. 31 is a configuration diagram of another conventional example.
FIG. 32 is a diagram for explaining the principle of capacitance-type water content detection.
FIG. 33 is an explanatory diagram of the relationship between moisture content and capacitance.
FIG. 34 is a schematic circuit configuration diagram of a capacitive moisture sensor.
FIG. 35 (a) is a front view in which a part of the arrangement part of the electrode part of the conventional example of the capacitive moisture sensor can be omitted.
(B) is a block diagram which shows the cross section which can be abbreviate | omitted corresponding to XX 'of (a).
[Explanation of symbols]
A Object to be detected
B container
1 Moisture sensor
12 Electrode section
12a, 12b electrode
13 Capacitance detection circuit
14 Output section
15 Insulation structure
16 opening

Claims (8)

An electrode unit comprising a pair of electrodes, in which a garbage treatment agent is a detection object, and the electrode surfaces are arranged substantially parallel to the wall surface so as not to protrude from the wall surface of the structure in contact with the detection object to the detection object side. A capacitance detection circuit that detects a capacitance value determined by the amount of moisture existing in the detection region, and a capacitance detection circuit that outputs a capacitor region composed of a pair of electrodes of the electrode unit, and is output from the capacitance detection circuit An output unit that outputs an amount of electricity corresponding to the detected capacitance value, and the distance between the pair of electrode ends of the electrode unit is a living object other than the detection target existing in the detection region. A capacitance type moisture sensor characterized in that it is at least twice the average size of dust . 2. The capacitance type moisture sensor according to claim 1, wherein a pair of electrodes of the electrode section are arranged side by side on substantially the same plane. At least one electrode, capacitive moisture content sensor according to claim 1, wherein the contact with the object to be detected through an insulator of a pair of electrodes of the electrode unit. Capacitive moisture content sensor according to claim 3, wherein the distance between the pair of electrodes, wherein the formation Rukoto as more than double the thickness of the insulating material of the electrode portion. Of the pair of electrodes of the electrode section, the other electrode connected to the other electrode connection end of the capacitance detection circuit is substantially around the one electrode connected to one electrode connection end of the capacitance detection circuit. The electrostatic capacity type moisture sensor according to any one of claims 1 to 4 , wherein the capacitive moisture sensor is arranged so as to surround . Capacitive moisture content sensor according to claim 5, characterized in that it comprises an electrode that is connected to the other electrode connecting end of the upper Symbol capacitance sensing circuit as ground. 6. The capacitance type moisture sensor according to claim 5 , wherein an electrode connected to the other electrode connection end of the capacitance detection circuit is the metal structure connected to the ground . Capacitive moisture content sensor according to any one of claims 1 to 6, characterized in that formed by the width of the pair of electrodes of the electrode portions substantially the same width.

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