JP3708208B2

JP3708208B2 - pH sensor and ion water generator

Info

Publication number: JP3708208B2
Application number: JP07270996A
Authority: JP
Inventors: 良二田中; 毅西田; 利彦松田; 琢磨佐藤; 哲司添田
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1996-03-27
Filing date: 1996-03-27
Publication date: 2005-10-19
Anticipated expiration: 2016-03-27
Also published as: JPH09264868A

Description

【０００１】
【発明の属する技術分野】
本発明は、イオン水等のｐＨ値を測定する際に使用され、内部液を充填したガラス電極で構成され、連続して通水される被測定液のｐＨを精度良く測定するｐＨセンサ及びそのｐＨセンサを使用したイオン水生成器に関するものである。
【０００２】
【従来の技術】
従来ｐＨセンサには半導体電極、イオン導電性隔膜電極及びガラス電極等で構成するものがあるが、操作性が良く価格が安い等の理由でガラス電極で構成したガラス電極型のｐＨセンサを使用することが多い。
【０００３】
そこで従来のガラス電極型のｐＨセンサについて説明する。ガラス電極型のｐＨセンサはガラス電極と比較電極で構成され、ガラス電極は露出されたｐＨ感知ガラス部と電圧を出力する内部電極と、内部電極を浸漬した内部液（ｐＨ＝７．０）とからなる。比較電極は内部電極を浸漬した中性塩溶液からなり、液絡部を介して被測定液と連通している。ガラス電極を直接多量の被測定液中に浸漬すると、被測定液のｐＨの大きさによってｐＨ感知ガラス部表面に接する水素イオンの濃度が変化し、それに対応して表面の電位が変化して内部電極に起電力を発生し、比較電極の電位と比較されセンサ電圧として出力される。しかしながらこのセンサ電圧は、ｐＨ感知ガラス部表面に接する水素イオンの濃度に依存することから、被測定液の量が充分に多い場合には水素イオンは安定してｐＨ感知ガラス部表面に供給されるため、精度良く安定してｐＨ測定できるものの、被測定液が微量の場合には表面を流れる被測定液の流れが悪くなり、また液中に含まれた気泡等の影響を受け水素イオンの供給が不安定となってセンサ電圧はバラツクし、精度も充分なものでないという問題があった。というのはこの従来のｐＨセンサはｐＨ感知ガラス部表面を開放・露出しておりそれを浸漬するための大きな流路空間と多量の被測定液を前提とするから、ｐＨ感知ガラス表面を通過する被測定液の流速がｐＨセンサと無関係に設計されており、微量の場合には被測定液の流量や気泡の影響が出るからである。このように連続的に通水しながらｐＨ測定する場合には多量の被測定液を必要とし、微少流量の領域では事実上測定が困難であった。
【０００４】
ｐＨ測定を微少の被測定液で行うのはこのように難しいが、通水をしないタイプのｐＨセンサとしては従来次のような技術（実開平１−６７５５９号公報）が提案されている。図３は従来のガラス電極型のｐＨセンサの概略構造図である。図３に示すように、ガラス電極４を内部に備えた円筒状外筒１の下端部に開口２を設けた保護キャップ３を取り付け、このｐＨ電極を予めビーカー等に採取した被測定液中に浸漬することにより、ｐＨを測定することができるようにしたものである。
【０００５】
また最近イオン水生成器が普及しているが、地方地方で原水のｐＨ値、ミネラル分、導電率が異なっているため生成されるイオン水のｐＨ値を制御する必要からｐＨセンサを設けたイオン水生成器も提案されている。
【０００６】
【発明が解決しようとする課題】
しかしながら、実開平１−６７５５９号公報に記載されたｐＨ測定用のｐＨ電極は、被測定液の量が多い場合にはその一部をサンプリングし、微量の場合にはサンプリングを重ねてビーカー等の容器に必要量を貯水することによって、被測定液の多少に関わらずｐＨが測定できるものの、煩雑にサンプリングを繰り返すこと以外連続して変化する被測定液のｐＨを測定することはできないし、これでは自動化できないという問題があった。また、被測定液が静止状態であるため被測定液中に含まれる気泡等がガラス電極表面に付着しやすいし、一旦付着した気泡等は剥がれにくく、そのためｐＨ測定を困難にするという問題があった。さらにガラス電極に炭化水素、炭酸塩スケール等が付着しやすく、応答時間が長くなると同時に測定精度が充分でない等の問題もあった。
【０００７】
そこで本発明は前記従来の問題点を解決するもので、簡単な構造からなり、連続して通水される被測定液に含まれる気泡を脱気し、ｐＨが精度良く安定して自動測定できる応答性に優れたｐＨセンサを提供することを目的とする。
【０００８】
また、本発明は安定して確実にイオン水のｐＨ値を自動的に検出でき、吐出されるイオン水のｐＨを制御することのできるイオン水生成器を提供することを目的とする。
【０００９】
【課題を解決するための手段】
上記目的を達成するために本発明のｐＨセンサは、ｐＨ感知ガラス部を備えて被測定液の水素イオン濃度を感知するガラス電極と、前記被測定液が通水されるとともに前記ｐＨ感知ガラス部が挿入された被測定液室を備え、前記被測定液室には前記被測定液が流入する流入路と前記流入路の上側に配置され前記被測定液が吐出される排水路を設け、前記流入路の被測定液室より所定上流側と排水路の被測定液室より所定下流側とを脱気路で連通し、前記被測定液に含まれ流入路に流入した気体を被測定液室に至る前に前記脱気路を介して排水路へ脱気するようにしたことを特徴とする。
【００１０】
これにより、簡単な構造からなり、連続して通水される被測定液に含まれる気泡を脱気し、ｐＨを精度良く安定して応答性よく自動測定することがきる。
【００１１】
【発明の実施の形態】
本発明の請求項１に記載の発明は、ｐＨ感知ガラス部を備えて被測定液の水素イオン濃度を感知するガラス電極と、前記被測定液が通水されるとともに前記ｐＨ感知ガラス部が挿入された被測定液室を備え、前記被測定液室には前記被測定液が流入する流入路と前記流入路の上側に配置され前記被測定液が吐出される排水路を設け、前記流入路の被測定液室より所定上流側と排水路の被測定液室より所定下流側とを脱気路で連通し、前記被測定液に含まれ流入路に流入した気体を被測定液室に至る前に前記脱気路を介して排水路へ脱気するようにしたものであり、流入路に流入した被測定液に含まれる水素ガス、酸素ガス、空気等の気泡はｐＨ感知ガラス部表面に達する前に脱気路を通過して排水路に合流されるという作用を有する。
【００１２】
また、請求項２に記載の発明は、電解槽と、電解槽に設けた一対の電極と、電解槽に接続された吐出路と、吐出路から分岐された分岐路とを備え、分岐路に前記記載のｐＨセンサを設けたものであり、微少流量の排水に挿入して被測定液のｐＨを測定でき、高精度にｐＨ制御されたイオン水を生成することができるという作用を有する。
【００１３】
以下、本発明の実施の形態について、図１、図２を用いて説明する。
（実施の形態１）
図１は本発明の実施の形態１におけるｐＨセンサの構造断面図で、１１はｐＨセンサ、１３はＡｇ／ＡｇＣｌからなる内部電極でｐＨ＝７．０の塩類溶液である内部液１８に浸漬してある。１６は被測定液室で被測定液２７が流入する流入路１４を下方側に、被測定液２７が吐出する排水路１５を上方側に設けてある。またこの被測定液室１６は、流入した被測定液２７がスムースに排水路１５から排水できるように流路抵抗を少なくするような構造にしている。流入路１４と排水路１５の間には流入する被測定液２７に含まれる気体を脱気する脱気路１０をバイパスして設けてある。２０は不活性ガラスからなるチューブ状のガラス電極で、その下端にはｐＨ感知ガラス部１２が設けられている。ｐＨ感知ガラス部１２は微量の酸化リチュウム等を含んだ球状の珪酸ガラスからなり、その内部に内部液１８が充填されている。この珪酸ガラスはリチュウムイオンが固体電解質として働いてイオン伝導性を示すことから、被測定液２７の水素イオン濃度に比例した電位がｐＨ感知ガラス部１２の外表面部に帯電されることになる。２３は比較電極室で内部に中性塩の溶液からなる比較電極液１９を充填し、比較電極液１９にＡｇ／ＡｇＣｌからなる比較電極２２を浸漬している。１７は液絡部で多孔性セラミック等からなり被測定液２７と比較電極液１９とを連通している。２１は比較電極液１９を補充する補充口で、２４は内部電極１３に接続された第１出力端子で、２５は比較電極２２に接続された第２出力端子で制御部２６に接続されている。２８はｐＨを表示するｐＨ表示部である。２９は仕切部で比較電極室２３と被測定液室１６を仕切るとともにガラス電極２０を貫通して固定している。この仕切部２９の下面側は排水路１５に向かって昇り勾配を形成して設けている。
【００１４】
ここで脱気路１０について説明する。この脱気路１０は流入路１４と排水路１５を連通して設けてあり、流入路１４に流入した気泡を含んだ被測定液２７は被測定液室１６に流入する前にこの脱気路１０の開口部近傍を通過する。このとき被測定液２７の一部は脱気路１０に分岐して流れ、これは排水路１５を流れる被測定液２７とともに排水される。ところで、被測定液２７に含まれている気泡の殆どは、水と比較して比重が小さいため流入路１４の路壁の上部に集まって、被測定液２７とともに被測定液室１６の方向に移動している。これらの気泡が脱気路１０の開口部に達すると後述するインジェクション効果により脱気路１０内を上昇させられ排水路１５に達し、そこを流れる被測定液２７に再び混入され排水される。このようにして被測定液２７に含まれる殆どの気泡は脱気されるが、残りの気泡は僅かではあるが被測定液室１６に混入する。しかしながら、これらの気泡は量的に限られるし、その大きさも極めて微細なものでそのまま被測定液２７に混入されたまま排水路１５から排水されるものである。
【００１５】
ここで流入路１４と排水路１５と脱気路１０の断面積の大きさは、流入路１４に比べて排水路１５と脱気路１０を小さくし、脱気路１０は排水路１５と同じかもしくは大きくするのが適当である。こうすることで気泡とともに分岐して排水される被測定液２７の量を少なく抑えることができるし、排水路１５内を流れる被測定液２７の流速が流入路１４内を流入する被測定液２７に比べて大きくなるから、インジェクション効果によって気泡を脱気しやすくする。また脱気路１０の開口部は流入路１４の上部側に設け、排水路１５の下部側に設けるのがよい。こうすることで被測定液２７に含まれる気泡が脱気しやすく、その殆どを脱気することができる。この実施の形態１では脱気路１０を１ヶ所にだけ設けているが、被測定液２７に含まれる気泡の量が多い場合には複数箇所に設けるのもよい。またこの実施の形態１では流入路１４と排水路１５を同一の方向に設けているが、流入路１４と排水路１５の方向を別々にして設けてもよく、その間に脱気路１０を脱気しやすい位置にバイパスするように設けることで同様な効果が得られる。
【００１６】
以上のように構成されたｐＨセンサについて、以下その動作を図１に基づいて説明する。水素ガス、酸素ガス及び空気等の気泡を含んだ被測定液２７は矢印ａの方向から流入路１４に流入する。流入した被測定液２７の一部は脱気路１０で分岐されるとともに被測定液２７に含有される気泡の殆どを脱気することができる。ここで脱気された被測定液２７が被測定液室１６を充満した後、脱気路１０を流れてきた気泡を含んだ被測定液２７とともに排水路１５から矢印ｂの方向に吐出される。このときｐＨ感知ガラス部１２が被測定液室１６内に挿入されており、被測定液２７の水素イオンがｐＨ感知ガラス部１２の表面に接触し内部液１８との間に起電力を発生する。一方被測定液２７は液絡部１７によって比較電極液１９と連通しており、比較電極液１９に浸した比較電極２２は被測定液２７に対して０電位となるので、第１出力端子２４と第２出力端子２５の間にｐＨ感知ガラス部１２の表面に接触し被測定液２７の水素イオン濃度に比例したセンサ電圧が出力される。このセンサ出力は次式で表される。
【００１７】
Ｅ＝α・０．０５９（ｐＨ0 −ｐＨ1 ）＋Ｃｖ
ただし、Ｅ：センサ電圧（Ｖ）
α：電極係数で０＜α≦１
ｐＨ０：内部液のｐＨ値で、ここではｐＨ＝７．０
ｐＨ１：被測定液のｐＨ値
Ｃｖ：電極固有の不斉電位差（Ｖ）
このｐＨセンサ１１は標準ｐＨセンサで、内部液１８のｐＨ0 を７．０としているので、被測定液２７のｐＨ1 が中性（ｐＨ＝７．０）であれば、不斉電位差Ｃｖを別にすればセンサ電圧が０Ｖということになる。一方、被測定液２７のｐＨ1 が酸性（ｐＨ＜７．０）であれば、不斉電位差Ｃｖを別にすればセンサ電圧（Ｅ）が正電圧となり、被測定液２７のｐＨ1 がアルカリ性（ｐＨ＞７．０）であれば、不斉電位差Ｃｖを別にしてセンサ電圧（Ｅ）が負電圧になる。この出力されたセンサ電圧（Ｅ）は制御部２６に伝達し必要に応じて増幅され、制御部２６はｐＨ表示部２８にｐＨ値表示したり、センサ電圧（Ｅ）をイオン水生成器等の制御機構に伝達し連続して生成するイオン水のｐＨ値を制御したりする。
【００１８】
このようにｐＨ感知ガラス部１２の表面に接触した被測定液２７の水素イオン濃度に比例したセンサ電圧（Ｅ）が出力されることから、ｐＨ感知ガラス部１２の表面は水素イオンが接触しやすいように保っておくことが必要となる。このｐＨ感知ガラス部１２の表面に気泡等が付着した場合には、接触する水素イオンの濃度が低くなり、結果的にセンサ電圧（Ｅ）が小さくなって被測定液２７の正確なｐＨ測定ができなくなる。またこの気泡等がｐＨ感知ガラス部１２の表面への付着、剥離を繰り返すことによってセンサ電圧（Ｅ）が変動し不安定になって精度よくｐＨ測定ができなくなるし応答時間も長くかかるようになる。しかしこの実施の形態１では気泡が脱気された被測定液２７がｐＨ感知ガラス部１２の表面に接触することから、その表面に気泡等が付着して水素イオンの接触を妨げることなく、正確に精度よくｐＨ測定することができる。
【００１９】
（実施の形態２）
つぎに本発明のｐＨセンサ１１を設けたイオン水生成器について説明する。図２は本発明の実施の形態２におけるイオン水生成器の全体概略図である。図２において、４１はイオン水生成器、４２は原水管、４３は内部に活性炭や中空糸膜などを備えた浄水部、４４は導電率を高めるミネラル添加筒、４５は電解槽、５０は第１電解室である陰極室、５２は第２電解室である陽極室である。４６は陰極側処理水吐出路、４７は陽極側処理水吐出路、４８ａは陰極側給水路、４８ｂは陽極側給水路、４９は陰極、５１は陽極、５３は陰極端子、５４は陽極端子である。５５は電解槽４５を２分する隔膜、５６は電源部、５７はｐＨセンサ３４のセンサ電圧に応じて両電極端子に印加する電圧を制御したりする制御部、５８はｐＨ濃度を表示するｐＨ表示部である。以上のように構成すると、第１電解室の処理水がアルカリ性イオン水となって陰極側処理水吐出路４６から吐出する。しかし、この実施の形態２で説明したものとは印加電圧の極性を逆にして、第１電解室を陽極室、第２電解室を陰極室にすると、第１電解室で生成される処理水が酸性イオン水となる。そこで、以下の説明は第１電解室を陰極室、第２電解室を陽極室として説明するが、極性を反転させたものも本実施の形態２のイオン水生成器４１に含まれるもので、このとき第１電解室が陽極室、第２電解室が陰極室で処理水が酸性イオン水となる点で相違するだけである。
【００２０】
３０は陰極室５０側の水を吐出する吐水の一部をｐＨセンサ３４に供給する分岐路、３５は分岐路３０に連結されアルカリ性イオン水の一部を通水する流入路、３２はアルカリ性イオン水の一部が通過する被測定液室、３３は水素イオンに感応するｐＨ応答ガラス膜を備えたｐＨ感知ガラス部、３１は測定が終了した被測定液を排出する排水路である。３６は脱気路で流入路３５と排水路３１の間にバイパスして設けてある。
【００２１】
以上のように構成されたイオン水生成器４１について以下その動作を説明する。原水管４２から矢印で示した様に給水された原水は浄水部４３及びミネラル添加筒４４を経由して陰極側給水路４８ａ及び陽極側給水路４８ｂから陰極室５０及び陽極室５２のそれぞれに給水される。原水が電解槽４５内に所定量流入した後に電源部５６からの電圧を制御部５７で所定の電圧に制御して、陰極端子５３には負電圧、陽極端子５４には正電圧を印加して電気分解を開始する。この電気分解によって電解槽４５ではアルカリ性イオン水と酸性イオン水が生成される。原水が連続して給水され、電圧が連続して印加されることによって陰極側処理水吐出路４６からは処理水であるアルカリ性イオン水が、陽極側処理水吐出路４７からは処理水である酸性イオン水が連続して吐出してくることになる。
【００２２】
このように生成されたアルカリ性イオン水の大部分は陰極側処理水吐出路４６を経て外部に吐出されるが、その一部のアルカリ性イオン水が陰極側処理水吐出路４６に設けた分岐路３０を経て流入路３５からｐＨセンサ３４の被測定液室３２に流入する。ところで電解槽４５で電気分解された処理水には電気分解の際発生したガスが混入しており、このうちアルカリ性イオン水には水素ガスが混入している。従ってこのアルカリ性イオン水がｐＨ感知ガラス部３３の表面部に接触しながら通過すると、ｐＨ感知ガラス部３３の表面にこの水素ガスの気泡が付着し、ｐＨ測定が困難に陥りやすいが、本実施の形態２では流入路３５と排水路３１にバイパスして脱気路３６を設けたｐＨセンサ３４を使用しているから、アルカリ性イオン水に水素ガスが混入していても精度よくｐＨを測定することができる。このｐＨ測定された被測定液は排水路３１より系外に排水されるが、排水路３１を陽極側処理水吐出路４７に接続するのが好ましい。ｐＨセンサ３４によりアルカリ性イオン水のｐＨを検知して、センサ電圧を制御部５７に送り、制御部５７はｐＨ表示部５８にｐＨを表示させるとともに、予め制御部５７に設けた記憶部に記憶させたｐＨになるように電極への印加電圧を制御してｐＨを調整することができる。
【００２３】
このように原水を連続して流入させ、陰極端子５３と陽極端子５４に連続的に電圧を印加しておくことによりアルカリ性イオン水が連続して生成させることができ、分岐路３０で分岐するアルカリ性イオン水の流量を少なくしてアルカリ性イオン水のｐＨ濃度の検知とその表示及びイオン水生成器の調整が同時に連続的に行え、排水するアルカリ性イオン水を少なくして無駄を少なくすることができる。
【００２４】
【発明の効果】
以上から明らかなように本発明のｐＨセンサは、ｐＨ感知ガラス部を備えて被測定液の水素イオン濃度を感知するガラス電極と、前記被測定液が通水されるとともに前記ｐＨ感知ガラス部が挿入された被測定液室を備え、前記被測定液室には前記被測定液が流入する流入路と前記流入路の上側に配置され前記被測定液が吐出される排水路を設け、前記流入路の被測定液室より所定上流側と排水路の被測定液室より所定下流側とを脱気路で連通し、前記被測定液に含まれ流入路に流入した気体を被測定液室に至る前に前記脱気路を介して排水路へ脱気するようにしたものである。
よって流入路に流入した被測定液に含まれる気泡は、被測定液室に流入する前に脱気路より排水路に脱気されて、排水路を流れる被測定液とともに排出されるので、ｐＨ測定の妨げになる気泡がｐＨ感知ガラス部の表面に付着することがなく、連続して通水される被測定液のｐＨを精度良く安定して応答性良く自動測定できるという効果を有する。
【００２５】
また、本発明のイオン水生成器は、生成されるイオン水から微少流量の被測定液を抜き出し、そのｐＨを短時間に自動測定し、制御部で正確にｐＨ制御することができるという効果を有する。
【図面の簡単な説明】
【図１】本発明の実施の形態１におけるｐＨセンサの構造断面図
【図２】本発明の実施の形態２におけるイオン水生成器の全体概略図
【図３】従来のガラス電極型のｐＨセンサの概略構造図
【符号の説明】
１円筒状外筒
２開口
３保護キャップ
４、２０ガラス電極
１０、３６脱気路
１１、３４ｐＨセンサ
１２、３３ｐＨ感知ガラス部
１３内部電極
１４、３５流入路
１５、３１排水路
１６、３２被測定液室
１７液絡部
１８内部液
１９比較電極液
２０ガラス電極
２１補充口
２２比較電極
２３比較電極室
２４第１出力端子
２５第２出力端子
２６、５７制御部
２７被測定液
２８、５８ｐＨ表示部
２９仕切部
３０分岐路
４１イオン水生成器
４２原水管
４３浄水部
４４ミネラル添加筒
４５電解槽
４６陰極側処理水吐出路
４７陽極側処理水吐出路
４８ａ陰極側給水路
４８ｂ陽極側給水路
４９陰極
５０陰極室
５１陽極
５２陽極室
５３陰極端子
５４陽極端子
５５隔膜
５６電源部[0001]
BACKGROUND OF THE INVENTION
The present invention is a pH sensor that is used when measuring a pH value of ionic water or the like, is configured with a glass electrode filled with an internal liquid, and accurately measures the pH of a liquid to be measured that is continuously passed through, and its The present invention relates to an ion water generator using a pH sensor.
[0002]
[Prior art]
Conventional pH sensors include semiconductor electrodes, ion conductive diaphragm electrodes, glass electrodes, etc., but glass electrode type pH sensors composed of glass electrodes are used for reasons such as good operability and low price. There are many cases.
[0003]
Therefore, a conventional glass electrode type pH sensor will be described. The glass electrode type pH sensor includes a glass electrode and a reference electrode. The glass electrode includes an exposed pH sensing glass part, an internal electrode that outputs voltage, and an internal liquid (pH = 7.0) in which the internal electrode is immersed. Consists of. The reference electrode is made of a neutral salt solution in which the internal electrode is immersed, and communicates with the liquid to be measured through the liquid junction. When the glass electrode is directly immersed in a large amount of liquid to be measured, the concentration of hydrogen ions in contact with the surface of the pH-sensing glass part changes depending on the pH of the liquid to be measured, and the surface potential changes accordingly. An electromotive force is generated in the electrode, which is compared with the potential of the comparison electrode and output as a sensor voltage. However, since this sensor voltage depends on the concentration of hydrogen ions in contact with the pH sensing glass surface, when the amount of the liquid to be measured is sufficiently large, hydrogen ions are stably supplied to the pH sensing glass surface. Therefore, the pH can be measured accurately and stably, but when the amount of the liquid to be measured is very small, the flow of the liquid to be measured flowing on the surface is deteriorated, and the supply of hydrogen ions is affected by the bubbles contained in the liquid. However, the sensor voltage varies and the accuracy is not sufficient. This is because the conventional pH sensor has an open / exposed surface of the pH-sensing glass and assumes a large flow path space for immersing it and a large amount of liquid to be measured, so it passes through the surface of the pH-sensing glass. This is because the flow rate of the liquid to be measured is designed irrespective of the pH sensor, and the flow rate of the liquid to be measured and the influence of bubbles are generated when the amount is small. Thus, in the case of measuring pH while continuously passing water, a large amount of liquid to be measured is required, and it was practically difficult to measure in a minute flow rate region.
[0004]
Although it is difficult to perform pH measurement with a very small liquid to be measured, the following technology (Japanese Utility Model Laid-Open No. 1-67559) has been proposed as a pH sensor that does not allow water to pass through. FIG. 3 is a schematic structural diagram of a conventional glass electrode type pH sensor. As shown in FIG. 3, a protective cap 3 provided with an opening 2 is attached to the lower end of a cylindrical outer cylinder 1 having a glass electrode 4 therein, and this pH electrode is collected in a liquid to be measured previously collected in a beaker or the like. The pH can be measured by dipping.
[0005]
In addition, ion water generators have recently become widespread. However, the pH value, mineral content, and conductivity of raw water are different in local areas, so it is necessary to control the pH value of the generated ion water. Water generators have also been proposed.
[0006]
[Problems to be solved by the invention]
However, the pH electrode for measuring pH described in Japanese Utility Model Laid-Open No. 1-67559 samples a part when the amount of the liquid to be measured is large, and repeats sampling when the amount is small, such as a beaker. By storing the required amount in the container, the pH can be measured regardless of the amount of the liquid to be measured, but the pH of the liquid to be measured that continuously changes cannot be measured except by repeating sampling. Then there was a problem that could not be automated. In addition, since the liquid to be measured is stationary, bubbles and the like contained in the liquid to be measured are likely to adhere to the glass electrode surface, and bubbles that have once adhered are difficult to peel off, which makes pH measurement difficult. It was. In addition, hydrocarbons, carbonate scales and the like are likely to adhere to the glass electrode, resulting in problems such as a long response time and insufficient measurement accuracy.
[0007]
Therefore, the present invention solves the above-mentioned conventional problems, has a simple structure, and degass bubbles contained in the liquid to be continuously passed, and can automatically measure the pH accurately and stably. An object is to provide a pH sensor excellent in responsiveness.
[0008]
It is another object of the present invention to provide an ionic water generator that can automatically and stably detect the pH value of ionic water and can control the pH of discharged ionic water.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a pH sensor of the present invention comprises a pH sensing glass part that senses the hydrogen ion concentration of a liquid to be measured , and the pH sensing glass part through which the liquid to be measured is passed. The measurement liquid chamber is provided with an inflow path through which the measurement liquid flows and a drainage path that is disposed above the inflow path and through which the measurement liquid is discharged, A predetermined upstream side from the liquid chamber to be measured in the inflow channel and a predetermined downstream side from the liquid chamber to be measured in the drainage channel are communicated by a deaeration channel, and the gas contained in the liquid to be measured and flowing into the inflow channel is measured It is characterized by deaeration to the drainage channel through the degassing channel before reaching the point.
[0010]
Thereby, it becomes a simple structure, The bubble contained in the to-be-measured liquid continuously passed can be deaerated, and pH can be measured automatically with high accuracy, stability, and stability.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, there is provided a glass electrode provided with a pH sensing glass part for sensing the hydrogen ion concentration of the liquid to be measured, and the pH sensing glass part is inserted while the liquid to be measured is passed through. A liquid chamber to be measured, and an inflow passage through which the liquid to be measured flows and a drainage passage which is disposed above the inflow passage and through which the liquid to be measured is discharged are provided in the measurement liquid chamber. A predetermined upstream side of the liquid chamber to be measured and a predetermined downstream side of the liquid chamber to be measured in the drainage channel are connected by a deaeration channel, and the gas contained in the liquid to be measured and flowing into the inflow channel reaches the liquid chamber to be measured. It is designed to deaerate to the drainage channel through the degassing channel before , and bubbles such as hydrogen gas, oxygen gas, air contained in the liquid to be measured flowing into the inflow channel are formed on the surface of the pH sensing glass part. It has the effect of passing through the deaeration channel and joining the drainage channel before reaching.
[0012]
The invention according to claim 2 includes an electrolytic cell, a pair of electrodes provided in the electrolytic cell, a discharge path connected to the electrolytic cell, and a branch path branched from the discharge path. The pH sensor described above is provided, and has an effect that it can be inserted into a small amount of waste water to measure the pH of the liquid to be measured, and ion water whose pH is controlled with high accuracy can be generated.
[0013]
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
(Embodiment 1)
FIG. 1 is a sectional view of the structure of a pH sensor according to Embodiment 1 of the present invention. 11 is a pH sensor, 13 is an internal electrode made of Ag / AgCl, and is immersed in an internal solution 18 that is a salt solution having a pH of 7.0. It is. Reference numeral 16 denotes a measured liquid chamber in which an inflow path 14 through which the measured liquid 27 flows is provided on the lower side and a drainage path 15 from which the measured liquid 27 is discharged is provided on the upper side. The liquid chamber 16 to be measured is structured to reduce the flow resistance so that the liquid 27 to be measured can be smoothly drained from the drainage channel 15. Between the inflow path 14 and the drainage path 15, a degassing path 10 for degassing the gas contained in the measured liquid 27 that flows in is bypassed. Reference numeral 20 denotes a tube-shaped glass electrode made of inert glass, and a pH sensing glass portion 12 is provided at the lower end thereof. The pH sensing glass part 12 is made of spherical silicate glass containing a small amount of lithium oxide or the like, and the inside is filled with an internal liquid 18. In this silicate glass, the lithium ion works as a solid electrolyte and exhibits ionic conductivity. Therefore, a potential proportional to the hydrogen ion concentration of the liquid 27 to be measured is charged on the outer surface portion of the pH sensing glass portion 12. A reference electrode chamber 23 is filled with a reference electrode solution 19 made of a neutral salt solution, and a reference electrode 22 made of Ag / AgCl is immersed in the reference electrode solution 19. Reference numeral 17 denotes a liquid junction portion which is made of porous ceramic or the like and communicates the measured liquid 27 and the comparative electrode liquid 19. Reference numeral 21 denotes a replenishing port for replenishing the comparison electrode solution 19, 24 denotes a first output terminal connected to the internal electrode 13, and 25 denotes a second output terminal connected to the comparison electrode 22, which is connected to the control unit 26. . Reference numeral 28 denotes a pH display unit for displaying pH. Reference numeral 29 denotes a partition that partitions the reference electrode chamber 23 and the measured liquid chamber 16 and penetrates and fixes the glass electrode 20. The lower surface side of the partition portion 29 is provided with a rising gradient toward the drainage channel 15.
[0014]
Here, the deaeration path 10 will be described. The deaeration channel 10 is provided so that the inflow channel 14 and the drainage channel 15 communicate with each other, and the measured liquid 27 containing bubbles flowing into the inflow channel 14 is supplied to the measured liquid chamber 16 before flowing into the measured liquid chamber 16. Pass through the vicinity of 10 openings. At this time, a part of the liquid to be measured 27 branches and flows into the deaeration passage 10, and is drained together with the liquid to be measured 27 flowing through the drainage passage 15. By the way, most of the bubbles contained in the liquid to be measured 27 have a specific gravity smaller than that of water, so that they gather at the upper part of the wall of the inflow passage 14 and move toward the liquid chamber 16 to be measured together with the liquid 27 to be measured. Has moved. When these bubbles reach the opening of the deaeration channel 10, the inside of the deaeration channel 10 is raised by an injection effect which will be described later, reaches the drainage channel 15, mixed again with the measured liquid 27 flowing therethrough, and drained. In this way, most of the bubbles contained in the liquid to be measured 27 are degassed, but the remaining bubbles are mixed in the liquid chamber 16 to be measured, although only a few. However, these bubbles are limited in quantity and are very fine in size, and are discharged from the drainage channel 15 while being mixed in the measured liquid 27 as they are.
[0015]
Here, the size of the cross-sectional area of the inflow channel 14, the drainage channel 15, and the deaeration channel 10 is smaller than that of the inflow channel 14, and the deaeration channel 10 is the same as the drainage channel 15. Or larger. By doing so, the amount of the liquid 27 to be measured that is branched and discharged together with the bubbles can be reduced, and the liquid 27 to be measured in which the flow rate of the liquid 27 to be measured flowing in the drainage channel 15 flows into the inflow channel 14. Since it becomes larger than the air bubble, it is easy to degas bubbles by the injection effect. The opening of the deaeration channel 10 is preferably provided on the upper side of the inflow channel 14 and provided on the lower side of the drainage channel 15. By doing so, bubbles contained in the liquid to be measured 27 are easily degassed, and most of them can be degassed. In the first embodiment, the deaeration path 10 is provided only at one place. However, when the amount of bubbles contained in the liquid to be measured 27 is large, it may be provided at a plurality of places. In the first embodiment, the inflow channel 14 and the drainage channel 15 are provided in the same direction. However, the inflow channel 14 and the drainage channel 15 may be provided in different directions, and the deaeration channel 10 is removed between them. A similar effect can be obtained by providing a bypass to a position where it is easy to care.
[0016]
The operation of the pH sensor configured as described above will be described below with reference to FIG. The liquid to be measured 27 containing bubbles such as hydrogen gas, oxygen gas and air flows into the inflow path 14 from the direction of the arrow a. A part of the liquid to be measured 27 that has flowed in is branched in the deaeration channel 10 and most of the bubbles contained in the liquid to be measured 27 can be degassed. After the measurement liquid 27 deaerated here fills the measurement liquid chamber 16, it is discharged from the drainage path 15 in the direction of the arrow b together with the measurement liquid 27 containing bubbles flowing through the deaeration path 10. . At this time, the pH sensing glass part 12 is inserted into the measured liquid chamber 16, and hydrogen ions of the measured liquid 27 come into contact with the surface of the pH sensing glass part 12 to generate an electromotive force between the internal liquid 18. . On the other hand, the liquid to be measured 27 is communicated with the comparative electrode liquid 19 by the liquid junction portion 17, and the comparison electrode 22 immersed in the comparative electrode liquid 19 becomes 0 potential with respect to the liquid to be measured 27. A sensor voltage proportional to the hydrogen ion concentration of the liquid to be measured 27 is output between the first output terminal 25 and the second output terminal 25. This sensor output is expressed by the following equation.
[0017]
E = α · 0.059 (pH 0 −pH 1) + Cv
Where E: Sensor voltage (V)
α: electrode coefficient 0 <α ≦ 1
pH0: pH value of the internal solution, here pH = 7.0
pH1: pH value of the solution to be measured
Cv: electrode-specific asymmetric potential difference (V)
Since this pH sensor 11 is a standard pH sensor and the pH 0 of the internal liquid 18 is 7.0, if the pH 1 of the liquid 27 to be measured is neutral (pH = 7.0), the asymmetric potential difference Cv is excluded. In this case, the sensor voltage is 0V. On the other hand, if the pH 1 of the liquid 27 to be measured is acidic (pH <7.0), the sensor voltage (E) becomes a positive voltage apart from the asymmetric potential difference Cv, and the pH 1 of the liquid 27 to be measured is alkaline (pH>). 7.0), the sensor voltage (E) becomes a negative voltage apart from the asymmetric potential difference Cv. The output sensor voltage (E) is transmitted to the control unit 26 and amplified as necessary. The control unit 26 displays the pH value on the pH display unit 28, or displays the sensor voltage (E) on an ion water generator or the like. The pH value of ionic water that is continuously transmitted to the control mechanism is controlled.
[0018]
Thus, since the sensor voltage (E) proportional to the hydrogen ion concentration of the liquid to be measured 27 in contact with the surface of the pH sensing glass unit 12 is output, the surface of the pH sensing glass unit 12 is likely to be in contact with hydrogen ions. It is necessary to keep it like this. When bubbles or the like adhere to the surface of the pH sensing glass portion 12, the concentration of hydrogen ions in contact with the surface decreases, and as a result, the sensor voltage (E) decreases and accurate pH measurement of the liquid to be measured 27 is performed. become unable. Further, when the bubbles or the like repeatedly adhere to and peel from the surface of the pH sensing glass part 12, the sensor voltage (E) fluctuates and becomes unstable, making it impossible to measure pH accurately and taking a long response time. . However, in the first embodiment, the measurement liquid 27 from which bubbles are degassed comes into contact with the surface of the pH sensing glass portion 12, so that bubbles do not adhere to the surface and the contact with hydrogen ions is prevented accurately. The pH can be measured with high accuracy.
[0019]
(Embodiment 2)
Next, an ion water generator provided with the pH sensor 11 of the present invention will be described. FIG. 2 is an overall schematic diagram of an ionic water generator according to Embodiment 2 of the present invention. In FIG. 2, 41 is an ionic water generator, 42 is a raw water pipe, 43 is a water purification unit having activated carbon, hollow fiber membranes and the like inside, 44 is a mineral addition cylinder for increasing conductivity, 45 is an electrolytic cell, and 50 is a first tank. A cathode chamber which is one electrolysis chamber and 52 is an anode chamber which is a second electrolysis chamber. 46 is a cathode side treated water discharge path, 47 is an anode side treated water discharge path, 48a is a cathode side water supply path, 48b is an anode side water supply path, 49 is a cathode, 51 is an anode, 53 is a cathode terminal, and 54 is an anode terminal. is there. 55 is a diaphragm that divides the electrolytic cell 45 into two parts, 56 is a power supply unit, 57 is a control unit that controls the voltage applied to both electrode terminals according to the sensor voltage of the pH sensor 34, and 58 is a pH that displays the pH concentration. It is a display unit. If comprised as mentioned above, the process water of a 1st electrolysis chamber turns into alkaline ionized water, and it discharges from the cathode side process water discharge path 46. FIG. However, when the polarity of the applied voltage is reversed from that described in the second embodiment and the first electrolysis chamber is the anode chamber and the second electrolysis chamber is the cathode chamber, the treated water generated in the first electrolysis chamber is generated. Becomes acidic ion water. Therefore, in the following description, the first electrolysis chamber is described as the cathode chamber, and the second electrolysis chamber is described as the anode chamber. However, the inverted polarity is also included in the ionic water generator 41 of the second embodiment. In this case, the only difference is that the first electrolysis chamber is the anode chamber, the second electrolysis chamber is the cathode chamber, and the treated water is acidic ion water.
[0020]
30 is a branch passage for supplying a part of water discharged from the cathode chamber 50 to the pH sensor 34, 35 is an inflow passage connected to the branch passage 30 for passing a part of alkaline ionized water, and 32 is an alkaline ion. A measured liquid chamber through which a part of water passes, 33 is a pH sensing glass part provided with a pH responsive glass film sensitive to hydrogen ions, and 31 is a drainage channel for discharging the measured liquid after measurement. Reference numeral 36 denotes a deaeration path which is bypassed between the inflow path 35 and the drainage path 31.
[0021]
The operation of the ionic water generator 41 configured as described above will be described below. The raw water supplied from the raw water pipe 42 as indicated by an arrow is supplied to the cathode chamber 50 and the anode chamber 52 from the cathode side water supply channel 48a and the anode side water supply channel 48b via the water purification unit 43 and the mineral addition tube 44, respectively. Is done. After a predetermined amount of raw water flows into the electrolytic cell 45, the voltage from the power supply unit 56 is controlled to a predetermined voltage by the control unit 57, and a negative voltage is applied to the cathode terminal 53 and a positive voltage is applied to the anode terminal 54. Start electrolysis. By this electrolysis, alkaline ionic water and acidic ionic water are generated in the electrolytic cell 45. When raw water is continuously supplied and voltage is continuously applied, alkaline ionized water that is treated water from the cathode side treated water discharge passage 46 and acidic water that is treated water from the anode side treated water discharge passage 47. Ionized water will be discharged continuously.
[0022]
Most of the alkaline ionized water generated in this way is discharged to the outside through the cathode side treated water discharge passage 46, and a part of the alkaline ionized water is provided in the cathode side treated water discharge passage 46. Then, it flows from the inflow path 35 into the measured liquid chamber 32 of the pH sensor 34. By the way, the gas generated at the time of electrolysis is mixed in the treated water electrolyzed in the electrolytic cell 45, and hydrogen gas is mixed in the alkaline ionized water. Therefore, when the alkaline ionized water passes while contacting the surface portion of the pH sensing glass portion 33, the hydrogen gas bubbles adhere to the surface of the pH sensing glass portion 33, and the pH measurement tends to be difficult. In the second embodiment, the pH sensor 34 provided with the deaeration channel 36 bypassed to the inflow channel 35 and the drainage channel 31 is used. Therefore, even if hydrogen gas is mixed in the alkaline ionized water, the pH is accurately measured. Can do. The measured liquid whose pH has been measured is drained from the drainage channel 31 to the outside of the system, and the drainage channel 31 is preferably connected to the anode-side treated water discharge channel 47. The pH sensor 34 detects the pH of the alkaline ionized water and sends the sensor voltage to the control unit 57. The control unit 57 displays the pH on the pH display unit 58 and stores it in a storage unit provided in the control unit 57 in advance. The pH can be adjusted by controlling the voltage applied to the electrode so as to achieve a high pH.
[0023]
In this way, by supplying raw water continuously and applying voltage continuously to the cathode terminal 53 and the anode terminal 54, alkaline ionized water can be continuously generated, and the alkalinity branched at the branch path 30. Detection of the pH concentration of alkaline ionic water, display thereof, and adjustment of the ionic water generator can be performed simultaneously by reducing the flow rate of ionic water, and the waste of alkaline ionic water to be drained can be reduced to reduce waste.
[0024]
【The invention's effect】
As is apparent from the above, the pH sensor of the present invention comprises a pH sensing glass part that senses the hydrogen ion concentration of the liquid to be measured , and the pH sensing glass part passes through the liquid to be measured. A liquid chamber to be measured is provided, and the liquid chamber to be measured is provided with an inflow path through which the liquid to be measured flows, and a drainage channel that is disposed above the inflow path and through which the liquid to be measured is discharged. A predetermined upstream side from the measured liquid chamber of the channel and a predetermined downstream side of the measured liquid chamber of the drainage channel are connected by a deaeration channel, and the gas contained in the measured liquid and flowing into the inflow channel is passed to the measured liquid chamber Before arriving, it is made to deaerate to a drainage channel via the said deaeration channel.
Therefore, bubbles contained in the measured liquid flowing into the inflow channel are degassed from the deaeration channel to the drainage channel before flowing into the measured solution chamber, and are discharged together with the measured solution flowing through the drainage channel. Bubbles that hinder measurement do not adhere to the surface of the pH sensing glass part, and the pH of the liquid to be continuously passed through can be automatically measured with high accuracy and stability and with good responsiveness .
[0025]
In addition, the ionic water generator of the present invention has the effect of extracting a liquid to be measured at a minute flow rate from the generated ionic water, automatically measuring the pH in a short time, and accurately controlling the pH by the control unit. Have.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of the structure of a pH sensor according to Embodiment 1 of the present invention. FIG. 2 is an overall schematic diagram of an ionic water generator according to Embodiment 2 of the present invention. Schematic structure diagram [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical outer cylinder 2 Opening 3 Protection cap 4, 20 Glass electrode 10, 36 Deaeration path 11, 34 pH sensor 12, 33 pH sensing glass part 13 Internal electrode 14, 35 Inflow path 15, 31 Drainage path 16, 32 Covered Measurement liquid chamber 17 Liquid junction 18 Internal liquid 19 Reference electrode liquid 20 Glass electrode 21 Replenishment port 22 Reference electrode 23 Reference electrode chamber 24 First output terminal 25 Second output terminal 26, 57 Control section 27 Liquid to be measured 28, 58 pH Display unit 29 Partition unit 30 Branch channel 41 Ionized water generator 42 Raw water pipe 43 Water purification unit 44 Mineral added tube 45 Electrolyzer 46 Cathode side treated water discharge channel 47 Anode side treated water discharge channel 48a Cathode side water supply channel 48b Anode side water supply channel 49 Cathode 50 Cathode chamber 51 Anode 52 Anode chamber 53 Cathode terminal 54 Anode terminal 55 Separator 56 Power supply

Claims

a glass electrode for detecting a hydrogen ion concentration of a liquid to be measured with a pH sensing glass part; and a liquid chamber for measurement to which the liquid to be measured is passed and the pH sensing glass part is inserted. The liquid chamber is provided with an inflow path through which the liquid to be measured flows and a drainage path that is disposed above the inflow path and through which the liquid to be measured is discharged. A predetermined downstream side of the liquid chamber to be measured is communicated with a predetermined degassing path, and the gas contained in the liquid to be measured and flowing into the inflow path is connected to the drainage path through the degassing path before reaching the liquid chamber to be measured. A pH sensor designed to deaerate .

2. The pH sensor according to claim 1, comprising an electrolytic cell, a pair of electrodes provided in the electrolytic cell, a discharge channel connected to the electrolytic cell, and a branch channel branched from the discharge channel. An ionic water generator characterized by comprising: