JP3447158B2 - Electrode type sensor - Google Patents
Electrode type sensorInfo
- Publication number
- JP3447158B2 JP3447158B2 JP22690595A JP22690595A JP3447158B2 JP 3447158 B2 JP3447158 B2 JP 3447158B2 JP 22690595 A JP22690595 A JP 22690595A JP 22690595 A JP22690595 A JP 22690595A JP 3447158 B2 JP3447158 B2 JP 3447158B2
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- measurement
- type sensor
- present
- cathode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、例えば、上水中の
残留塩素濃度を測定するためのセンサーのような、電解
質溶液である試料中に電極を浸漬させることにより両電
極間に生じる起電力を感知する電極型センサーに関する
ものである。
【０００２】
【従来の技術】電極型センサーは、試料液中に浸漬する
ことにより電極表面に汚れが付着し易く、これを防止す
る機構を備えることが必要である。
【０００３】従来、電極型センサーの汚れ防止機構とし
ては、セラミックビーズ等の研磨剤で満たされたセル内
で電極が回転し、常に電極表面が磨かれた状態を保持す
るものや、セル自体に超音波洗浄機構が内蔵され、電極
表面への汚れの付着を防止するものが知られている。
【０００４】
【発明が解決しようとする課題】しかし、これら従来の
電極型センサーの汚れ防止機構においては、いずれの場
合も、洗浄機能を駆動させるのにある程度の電力を消費
するため、電源が必要となり、しかも、セルの小型化に
限界があるため、測定に比較的多量の試料が必要であっ
た。従って、従来の電解型センサーは、その設置が限ら
れた場所に限定されており、例えば、管路内の残留塩素
濃度を測定するうえで有効な採水地点である、消火栓室
内への設置は極めて困難であった。
【０００５】本発明は、このような問題を解決するもの
で、駆動に電力等のエネルギーを必要としない簡易な機
構で、電極の汚れを防止することができる電極型センサ
ーを提供するものである。
【０００６】
【課題を解決するための手段】この課題を解決するため
に、本発明の電極型センサーは、陽極となる第一の電極
と陰極となる第二の電極とを有し、両電極を電解質溶液
である試料中に浸漬させることにより両電極間に生じる
起電力を感知する電極型センサーであって、前記陰極と
なる第二の電極よりも標準電極電位が低い第三の電極を
前記試料中に浸漬させ得る状態で備え、かつ、測定時に
は第二の電極を測定系を介して第一の電極に接続させ、
非測定時には第二の電極と第三の電極とを接続させるた
めの切り替え手段を具備することを要旨とする。
【０００７】そして本発明では、このような構成によ
り、非測定時には、測定時に陰極であった第二の電極が
陽極となり、第三の電極が陰極となる。通常、電極型セ
ンサーでは、陽極は殆ど汚れないのに比べ陰極の汚れが
顕著であるが、このように非測定時には第二の電極を陽
極として機能させることで、この第二の電極への汚れの
付着を防止することができるものである。
【０００８】
【発明の実施の形態】本発明においては、第一〜第三の
各電極は、以下の条件を満足する組み合わせでさえあれ
ば、それぞれ特に制限はなく、センサーの用途に応じて
適宜選択すれば良い。すなわち、各電極がそれぞれ異な
る標準電極電位を有し、しかも第一の電極の標準電極電
位が最も高く、第三の電極の標準電極電位が最も低く、
第二の電極の標準電極電位がその中間となるように組み
合わせることが重要である。たとえば、図１、図２に示
すように、第一の電極として銀−塩化銀電極１を用い、
第二の電極として銀−塩化銀電極１よりも標準電極電位
が低い白金電極２を用い、第三の電極として白金電極２
よりもさらに標準電極電位が低い金電極３を用いること
ができ、これは残留塩素濃度測定用のセンサーとして好
適である。
【０００９】本発明における切り替え手段は、測定時に
は図１に示すように第二の電極（白金電極２）を出力端
子５に接続される測定系を介して第一の電極（銀−塩化
銀電極１）に接続させた第一の回路形態を可能にし、非
測定時には図２に示すように第二の電極（白金電極２）
と第三の電極（金電極３）とを接続させた第二の回路形
態を可能にするものである。例えば、切り替え手段とし
ては、一定時間毎に自動的に接続点を切り替えることが
できるプログラムタイマーによる自動切り替え装置４が
好適である。なお、本発明においては、その他の自動式
の切り替え装置や手動式の切り替え装置であっても差し
支えない。
【００１０】本発明の電極型センサーが、電極への汚れ
の付着を防止する機構は、以下のように推測される。す
なわち、電極の汚れは主として陰極側の汚れによるもの
であり、これは陰極が電気的に負となることから、試料
中のＣａ2+，Ｆｅ2+，Ｍｎ2+等の陽イオンや正の電荷を
帯びた粒子を引き寄せ、これらが陰極表面に付着するた
めと考えられる。一方、陽極側では、同様にＣｌ- やＯ
Ｈ- 等の陰イオンが引き寄せられるが、これらは容易に
水中に溶け込み、電極表面に汚れとして付着し難いと考
えられる。従って、本発明においては、測定時に陰極で
あった第二の電極（白金電極２）を、非測定時に第三の
電極（金電極３）と接続することにより、第二の電極
（白金電極２）が陽極となり、第三の電極（金電極３）
が陰極となる状態で待機させることができ、第二の電極
（白金電極２）への汚れの付着を防止することができ
る。この際、第三の電極（金電極３）に汚れが付着する
ことになるが、第三の電極（金電極３）は測定には関与
しないので、出力に与える影響はない。また、水中の汚
れが第三の電極（金電極３）に集められることによって
も、第二の電極（白金電極２）での汚れ発生が効果的に
防止されることになる。
【００１１】また、本発明の電極型センサーの第一〜第
三の各電極は、測定の正確さを維持するため、試料中に
浸漬し得るよう配置されていなければならない。詳しく
は、測定時は少なくとも第一の電極と第二の電極とが試
料に浸かり、非測定時は少なくとも第二の電極と第三の
電極とが試料に浸かっていることが必要である。
【００１２】
【実施例】次に、本発明の電極型センサーを実施例と
し、従来の電極型センサーを比較例としてこれらを比較
する。
【００１３】実施例として、図１、図２に示す残留塩素
濃度測定用センサーを用いた。前述のように、第一の電
極として銀−塩化銀電極１を、第二の電極として白金電
極２を、第三の電極として金電極３を組み合わせ、切り
替え手段としてはプログラムタイマーによる自動切り替
え装置４を白金電極２に接続して用いた。この自動切り
替え装置４は、測定時には出力端子５と白金電極２とを
接続し、出力端子５を介して白金電極２と銀−塩化銀電
極１とを繋げる回路（図１参照）とし、非測定時には金
電極３と白金電極２とを直接接続する回路（図２参照）
とすることができるものであって、２〜３分に１回かあ
るいはそれよりも長いインターバルで測定時の回路（図
１参照）に切り替え、測定終了後はプログラムタイマー
が動作し、白金電極２と出力端子５との接続は切断さ
れ、白金電極２と金電極３とが接続された回路（図２参
照）で待機させるものである。このような残留塩素濃度
測定センサーは、測定時には、白金／銀−塩化銀による
カルバニセル電極として働くもので、白金／銀−塩化銀
による起電力が残留塩素の濃度に比例して発生すること
を利用して残留塩素濃度を測定するものである。
【００１４】また、比較例として、前記実施例と同一の
構成であって、第三の電極（金電極３）および切り替え
手段（自動切り替え装置４）を持たない残留塩素濃度測
定センサーを用い、非測定時にも図１に示す測定時の回
路形態で待機させた。
【００１５】水道管内の上水を測定対象として、本実施
例および比較例の残留塩素濃度測定センサーにより残留
塩素濃度を測定した。本実施例および比較例についての
残留塩素濃度の経時的変化を示すグラフを図３に示す。
【００１６】このグラフから明らかなように、試験開始
後約７日経過付近から、比較例は汚れ付着による出力低
下が発生し、時間の経過にともない本実施例との出力差
が大きくなった。このことから、本発明のセンサーは、
優れた汚れ防止効果を発揮することが判る。
【００１７】なお、本発明の電極型センサーは、本実施
例の残留塩素センサーに限定されるものではなく、例え
ば電気伝導度センサー等の電解溶液中で使用するあらゆ
る電極型センサーに適用できるものである。
【００１８】
【発明の効果】以上のように本発明の電極型センサー
は、測定時に陰極となる第二の電極よりも標準電極電位
の低い第三の電極を有し、非測定時に第二の電極を第三
の電極と接続し、第二の電極を陽極、第三の電極を陰極
とすることにより、非測定時には第二の電極が陰極とし
て作用することがなくなり、このため第二の電極への汚
れの付着を防止することができる。従って、本発明は、
駆動に電力等のエネルギーを必要としない簡易な機構
で、電極の汚れを防止することができる電極型センサー
を提供し得るものであり、よって消火栓室内等への電極
型センサーの設置をも容易にするものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of immersing an electrode in a sample which is an electrolyte solution, such as a sensor for measuring the concentration of residual chlorine in tap water. The present invention relates to an electrode type sensor for detecting an electromotive force generated between both electrodes. 2. Description of the Related Art An electrode-type sensor is apt to adhere to the electrode surface by being immersed in a sample solution, and it is necessary to provide a mechanism for preventing this. Conventionally, as a mechanism for preventing contamination of an electrode-type sensor, an electrode is rotated in a cell filled with an abrasive such as ceramic beads to keep the electrode surface constantly polished. There is known an apparatus having a built-in ultrasonic cleaning mechanism for preventing adhesion of dirt to an electrode surface. [0004] However, in any of these conventional electrode type sensor dirt prevention mechanisms, a certain amount of power is consumed to drive the cleaning function, so that a power supply is required. In addition, since there is a limit to miniaturization of the cell, a relatively large amount of sample is required for measurement. Therefore, the conventional electrolytic type sensor is limited to a limited installation location.For example, installation in a fire hydrant room, which is an effective water sampling point for measuring the residual chlorine concentration in a pipeline, is difficult. It was extremely difficult. The present invention solves such a problem, and provides an electrode-type sensor that can prevent electrode contamination with a simple mechanism that does not require energy such as electric power for driving. . In order to solve this problem, an electrode-type sensor according to the present invention has a first electrode serving as an anode and a second electrode serving as a cathode. An electrode-type sensor that senses an electromotive force generated between both electrodes by immersing the electrode in a sample that is an electrolyte solution, wherein the third electrode having a lower standard electrode potential than the second electrode serving as the cathode is the third electrode. Prepared in a state that can be immersed in the sample, and, at the time of measurement, connect the second electrode to the first electrode via a measurement system,
The gist of the present invention is to provide a switching unit for connecting the second electrode and the third electrode at the time of non-measurement. In the present invention, with such a configuration, the second electrode, which was a cathode at the time of measurement, becomes an anode and the third electrode becomes a cathode during non-measurement. Normally, in an electrode type sensor, the anode is hardly soiled compared to the case where the anode is almost unstained. In this way, when the measurement is not performed, the second electrode functions as the anode, so that the second electrode can be soiled. Can be prevented from adhering. [0008] In the present invention, each of the first to third electrodes is not particularly limited as long as the combination satisfies the following conditions, and is appropriately determined according to the use of the sensor. Just choose. That is, each electrode has a different standard electrode potential, the first electrode has the highest standard electrode potential, the third electrode has the lowest standard electrode potential,
It is important to combine such that the standard electrode potential of the second electrode is in the middle. For example, as shown in FIGS. 1 and 2, a silver-silver chloride electrode 1 is used as a first electrode,
A platinum electrode 2 having a standard electrode potential lower than that of the silver-silver chloride electrode 1 was used as a second electrode, and a platinum electrode 2 was used as a third electrode.
A gold electrode 3 having a lower standard electrode potential than that can be used, which is suitable as a sensor for measuring residual chlorine concentration. The switching means in the present invention is arranged such that the second electrode (platinum electrode 2) is connected to the first electrode (silver-silver chloride electrode) via a measuring system connected to the output terminal 5 as shown in FIG. The first circuit configuration connected to 1) is enabled, and the second electrode (platinum electrode 2) as shown in FIG.
And a third circuit (gold electrode 3) connected to the second circuit. For example, as the switching means, an automatic switching device 4 using a program timer that can automatically switch the connection point at regular intervals is suitable. In the present invention, other automatic switching devices or manual switching devices may be used. The mechanism by which the electrode type sensor of the present invention prevents the adhesion of dirt to the electrodes is presumed as follows. That is, the stain on the electrode is mainly caused by the stain on the cathode side. Since the cathode is electrically negative, the cation such as Ca 2+ , Fe 2+ , Mn 2+ or the like in the sample is positive. This is presumably because the charged particles are attracted and adhere to the cathode surface. On the other hand, on the anode side, Cl - and O
H - Although anions such are attracted, it readily dissolves in water, is considered less likely to adhere as dirt to the surface of the electrode. Therefore, in the present invention, the second electrode (platinum electrode 2), which was a cathode at the time of measurement, is connected to the third electrode (gold electrode 3) at the time of non-measurement. ) Becomes the anode and the third electrode (gold electrode 3)
Can be made to stand by in a state where it becomes a cathode, and the adhesion of dirt to the second electrode (platinum electrode 2) can be prevented. At this time, dirt adheres to the third electrode (gold electrode 3), but the third electrode (gold electrode 3) has no influence on the output because it is not involved in the measurement. In addition, since the dirt in the water is collected on the third electrode (gold electrode 3), the generation of dirt on the second electrode (platinum electrode 2) is effectively prevented. Further, the first to third electrodes of the electrode type sensor according to the present invention must be arranged so as to be immersed in the sample in order to maintain the accuracy of the measurement. Specifically, it is necessary that at least the first electrode and the second electrode are immersed in the sample at the time of measurement, and at least the second electrode and the third electrode are immersed in the sample at the time of non-measurement. Next, the electrode type sensor of the present invention will be described as an example, and a conventional electrode type sensor will be compared as a comparative example. As an example, a sensor for measuring the residual chlorine concentration shown in FIGS. 1 and 2 was used. As described above, the silver-silver chloride electrode 1 is used as the first electrode, the platinum electrode 2 is used as the second electrode, and the gold electrode 3 is used as the third electrode. Was connected to the platinum electrode 2 for use. The automatic switching device 4 connects the output terminal 5 and the platinum electrode 2 at the time of measurement, and forms a circuit (see FIG. 1) connecting the platinum electrode 2 and the silver-silver chloride electrode 1 via the output terminal 5 to perform non-measurement. Sometimes a circuit that directly connects the gold electrode 3 and the platinum electrode 2 (see FIG. 2)
The circuit is switched to the circuit at the time of measurement (see FIG. 1) once every two to three minutes or at intervals longer than that, and after the measurement is completed, the program timer operates and the platinum electrode 2 is turned on. The connection between the electrode and the output terminal 5 is cut off, and a standby is made in a circuit (see FIG. 2) in which the platinum electrode 2 and the gold electrode 3 are connected. Such a residual chlorine concentration measuring sensor functions as a platinum / silver-silver chloride carbanicell electrode at the time of measurement, and utilizes the fact that an electromotive force generated by platinum / silver-silver chloride is generated in proportion to the concentration of residual chlorine. To measure the residual chlorine concentration. As a comparative example, a residual chlorine concentration measuring sensor having the same configuration as that of the above-mentioned embodiment and having no third electrode (gold electrode 3) and no switching means (automatic switching device 4) was used. At the time of the measurement, the circuit was kept on standby in the circuit configuration at the time of the measurement shown in FIG. The residual chlorine concentration was measured by using the residual chlorine concentration measuring sensors of the present embodiment and the comparative example, with the tap water in the water pipe being measured. FIG. 3 is a graph showing the change over time in the residual chlorine concentration for the present example and the comparative example. As is apparent from this graph, the output of the comparative example decreased due to the adhesion of dirt from about 7 days after the start of the test, and the output difference from the present example increased with time. From this, the sensor of the present invention is:
It can be seen that an excellent dirt prevention effect is exhibited. The electrode type sensor of the present invention is not limited to the residual chlorine sensor of the present embodiment, but can be applied to any electrode type sensor used in an electrolytic solution such as an electric conductivity sensor. is there. As described above, the electrode-type sensor of the present invention has the third electrode having a standard electrode potential lower than the second electrode serving as the cathode during measurement, and the second electrode when not measuring. By connecting the electrode to the third electrode and using the second electrode as the anode and the third electrode as the cathode, the second electrode does not act as the cathode during non-measurement. It is possible to prevent dirt from adhering. Therefore, the present invention
It is possible to provide an electrode-type sensor that can prevent electrode contamination with a simple mechanism that does not require energy such as electric power for driving, so that the electrode-type sensor can be easily installed in a fire hydrant room or the like. Is what you do.
【図面の簡単な説明】
【図１】本発明の一実施例における電極型センサーの測
定時の概略図である。
【図２】本発明の一実施例における電極型センサーの非
測定時の概略図である。
【図３】本発明の実施例および従来例における残留塩素
濃度の経時的変化を示すグラフである。
【符号の説明】
１ 銀−塩化銀電極
２ 白金電極
３ 金電極
４ 自動切り替え装置
５ 出力端子BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an electrode-type sensor according to an embodiment of the present invention at the time of measurement. FIG. 2 is a schematic diagram of an electrode-type sensor according to an embodiment of the present invention at the time of non-measurement. FIG. 3 is a graph showing a change over time of a residual chlorine concentration in an example of the present invention and a conventional example. [Description of Signs] 1 silver-silver chloride electrode 2 platinum electrode 3 gold electrode 4 automatic switching device 5 output terminal
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭53−85496（ＪＰ，Ａ) 特開 昭62−8050（ＪＰ，Ａ) 実開 昭54−174395（ＪＰ，Ｕ) 実開 昭61−178462（ＪＰ，Ｕ) 実開 昭56−31353（ＪＰ，Ｕ) 特公 昭40−5478（ＪＰ，Ｂ１) (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 27/416 G01N 27/38 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-85496 (JP, A) JP-A-62-8050 (JP, A) Fully open 1979-174395 (JP, U) Really open 1986 178462 (JP, U) JP-A 56-31353 (JP, U) JP-B 40-5478 (JP, B1) (58) Fields investigated (Int. Cl. 7 , DB name) G01N 27/416 G01N 27 / 38
Claims (1)
の電極とを有し、両電極を電解質溶液である試料中に浸
漬させることにより両電極間に生じる起電力を感知する
電極型センサーであって、前記陰極となる第二の電極よ
りも標準電極電位が低い第三の電極を前記試料中に浸漬
させ得る状態で備え、かつ、測定時には第二の電極を測
定系を介して第一の電極に接続させ、非測定時には第二
の電極と第三の電極とを接続させるための切り替え手段
を具備することを特徴とする電極型センサー。(57) [Claim 1] It has a first electrode serving as an anode and a second electrode serving as a cathode, and both electrodes are immersed in a sample which is an electrolyte solution. An electrode-type sensor for sensing an electromotive force generated between the electrodes, wherein the third electrode having a lower standard electrode potential than the second electrode serving as the cathode is provided in a state in which the third electrode can be immersed in the sample, and at the time of measurement. An electrode-type sensor comprising: a switching unit for connecting a second electrode to a first electrode via a measurement system and connecting the second electrode and the third electrode when measurement is not performed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22690595A JP3447158B2 (en) | 1995-09-05 | 1995-09-05 | Electrode type sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22690595A JP3447158B2 (en) | 1995-09-05 | 1995-09-05 | Electrode type sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0972879A JPH0972879A (en) | 1997-03-18 |
| JP3447158B2 true JP3447158B2 (en) | 2003-09-16 |
Family
ID=16852443
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22690595A Expired - Fee Related JP3447158B2 (en) | 1995-09-05 | 1995-09-05 | Electrode type sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3447158B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3328215B2 (en) * | 1999-04-13 | 2002-09-24 | 株式会社メルス技研 | Residual chlorine measuring device |
| JP2008058025A (en) * | 2006-08-29 | 2008-03-13 | Omega:Kk | Residual chlorine concentration meter |
| JP5416501B2 (en) * | 2009-07-27 | 2014-02-12 | 株式会社 堀場アドバンスドテクノ | Water quality measuring device |
| JP7058167B2 (en) * | 2018-04-13 | 2022-04-21 | 愛知時計電機株式会社 | Residual chlorine concentration measuring device and water meter |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5385496A (en) * | 1976-12-30 | 1978-07-27 | Fuji Electric Co Ltd | Dissolved oxygen meter |
| JPS5820928Y2 (en) * | 1978-05-30 | 1983-05-02 | 横河電機株式会社 | electrochemical measuring device |
| JPS5631353U (en) * | 1979-08-17 | 1981-03-26 | ||
| JPH0438284Y2 (en) * | 1985-04-27 | 1992-09-08 | ||
| JPS628050A (en) * | 1985-07-05 | 1987-01-16 | Nippon Fuirukon Kk | Method and apparatus for measuring concentration of oxidizable substance in liquid to be inspected |
-
1995
- 1995-09-05 JP JP22690595A patent/JP3447158B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0972879A (en) | 1997-03-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |