JP2006030027A - Sensitivity restoring method of diaphragm type sensor, measuring instrument and electrode regeneration device - Google Patents

Sensitivity restoring method of diaphragm type sensor, measuring instrument and electrode regeneration device Download PDF

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JP2006030027A
JP2006030027A JP2004210578A JP2004210578A JP2006030027A JP 2006030027 A JP2006030027 A JP 2006030027A JP 2004210578 A JP2004210578 A JP 2004210578A JP 2004210578 A JP2004210578 A JP 2004210578A JP 2006030027 A JP2006030027 A JP 2006030027A
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sensitivity
electrode
working electrode
diaphragm
current
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Hiroko Konno
裕子 金野
Naomi Narasaki
直美 楢崎
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DKK TOA Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensitivity restoring method of a diaphragm type sensor capable of easily restoring sensitivity, and to provide a measuring instrument and an electrode regeneration device. <P>SOLUTION: A diaphragm 13 for transmitting a component to be measured in a sample is provided to one end of a sensor main body 11 in a freely detachable manner, and an acting electrode 14 having a platinum group metal catalyst layer or a platinum plating layer P on its surface and a counter electrode 15 are arranged in a chamber 11a demarcated from the outside by the diaphragm 13. The component to be measured transmitted through the diaphragm 13 is reacted with the surface of the acting electrode 14 in a state that the acting electrode 14 and the counter electrode 15 are in contact with the electrolyte 17 housed in the chamber 11a to restore the sensitivity of the diaphragm type sensor 10A for measuring the measuring current flowing across the acting electrode 14 and the counter electrode 15. A sensitivity restoring current different from the measuring current is allowed to flow to the acting electrode 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、白金族触媒層又は白金メッキ層が設けられた電極を有する隔膜型センサの感度復帰方法、計測装置及び電極再生装置に関するものである。   The present invention relates to a sensitivity return method, a measuring device, and an electrode regeneration device for a diaphragm type sensor having an electrode provided with a platinum group catalyst layer or a platinum plating layer.

従来、例えば、原子力発電プラントなどでは試料（被検液）中の溶存水素（還元体）の測定が重要であり、計器によるモニタリングが行われている。この溶存水素計で用いる溶存水素センサ（又は水素ガスセンサ）として、測定対象ガス透過性膜として水素透過性の隔膜を使用したポーラログラフ式の隔膜型センサが主に用いられている。   Conventionally, for example, in a nuclear power plant or the like, it is important to measure dissolved hydrogen (reduced substance) in a sample (test solution), and monitoring by a meter is performed. As a dissolved hydrogen sensor (or hydrogen gas sensor) used in this dissolved hydrogen meter, a polarographic diaphragm type sensor using a hydrogen permeable membrane as a gas permeable membrane to be measured is mainly used.

従来の隔膜型センサの一例として、上記溶存水素計のセンサとして用いられる隔膜型ポーラログラフ式センサ（以下、単に「隔膜型センサ」という。）について説明すると、図１に示すように、隔膜型センサ１０Ａは、一般に、白金又は白金族触媒で形成される作用極１４と、通常、銀（Ａｇ）或いは銀−塩化銀（Ａｇ／ＡｇＣｌ）で形成される対極１５と、これらの電極に接触する電解液１７と、水素を選択的に透過する隔膜１３とを備えている（２極式）。又、更に参照極を備えたものもある（３極式）。   As an example of a conventional diaphragm type sensor, a diaphragm type polarographic sensor (hereinafter simply referred to as “diaphragm type sensor”) used as a sensor of the dissolved hydrogen meter will be described. As shown in FIG. Is generally a working electrode 14 formed of platinum or a platinum group catalyst, a counter electrode 15 usually formed of silver (Ag) or silver-silver chloride (Ag / AgCl), and an electrolytic solution in contact with these electrodes. 17 and a diaphragm 13 that selectively permeates hydrogen (bipolar type). In addition, there are also those equipped with a reference electrode (three-pole type).

例えば、図１を参照して２極式のものについて更に説明すれば、隔膜１３を通過した水素が電解液１７中に溶解して行き、作用極１４上において酸化される。そして、電解液１７を介して対極１５との間で電気化学反応が起こり、そのときに作用極１４と対極１５との間に流れる電流（測定電流）が水素ガス濃度に比例することを利用して、電流値より水素ガス濃度を知ることができる。   For example, referring to FIG. 1, the bipolar type will be further described. Hydrogen that has passed through the diaphragm 13 is dissolved in the electrolytic solution 17 and is oxidized on the working electrode 14. Then, an electrochemical reaction takes place between the working electrode 14 and the counter electrode 15 via the electrolytic solution 17 and the current (measurement current) flowing between the working electrode 14 and the counter electrode 15 is proportional to the hydrogen gas concentration. Thus, the hydrogen gas concentration can be known from the current value.

上述のように、隔膜型センサ１０Ａでは、作用極１４での反応により作用極１４と対極１５との間に流れる電流量（酸化電流）を測定するが、計測開始直後から徐々に感度が劣化するため、頻繁に感度校正をしなければならず、連続測定が困難であった。   As described above, the diaphragm type sensor 10A measures the amount of current (oxidation current) flowing between the working electrode 14 and the counter electrode 15 due to the reaction at the working electrode 14, but the sensitivity gradually deteriorates immediately after the start of measurement. Therefore, sensitivity calibration must be frequently performed, and continuous measurement is difficult.

この問題を解決するために、作用極１４の表面に白金黒メッキを行い（白金黒電極）、作用極１４の表面活性を上げることにより感度を維持する方法がとられている。白金黒は、金属白金が非常に細かな海綿状（粉状）になったもので、これが付着した電極は、見掛けの表面積に比べて実表面積が著しく広く、且つ、顕微鏡的に凹凸が大きい。   In order to solve this problem, a method of maintaining the sensitivity by performing platinum black plating on the surface of the working electrode 14 (platinum black electrode) and increasing the surface activity of the working electrode 14 is employed. Platinum black is a metallic spongy (powdered) metal platinum, and the electrode to which it is attached has a significantly larger actual surface area than the apparent surface area, and has a large microscopic unevenness.

しかし、作用極に白金黒メッキを施しても、感度劣化はゼロではない。従って、従来、極表面に白金黒メッキをした隔膜型センサの感度が劣化した場合には、隔膜を取り外し、極に白金黒を再メッキすることで、感度復帰させることが行われている。   However, even if platinum black plating is applied to the working electrode, the sensitivity deterioration is not zero. Therefore, conventionally, when the sensitivity of a diaphragm type sensor having platinum black plating on the pole surface deteriorates, the sensitivity is restored by removing the diaphragm and replating platinum black on the pole.

白金黒メッキの再メッキは、次のような手順で行う。白金黒メッキが施された作用極をビーカー等に入った研磨砂に押しつけ、古い白金黒がなくなり金属地肌が露出するまで研磨を繰り返す。その後、研磨砂を取り除き、更に作用極をアルコール等に浸漬して超音波洗浄機で繰り返し洗浄する。そして、作用極を乾燥させた後、メッキ操作に入る。メッキ操作は、概略次のようにして行う。先ず、メッキ容器（ビーカーなど）内にメッキ液を入れ、このメッキ液に電極の少なくとも作用極の接液表面（カソード）を浸漬し、電流発生器の負極をリード線を介して接続する。一方、別途、メッキ液に白金極（アノード）を浸漬し、リード線を介して電流発生器の正極を接続する。そして、作用極と白金極との間に電流発生器から電流を流すことによって、作用極に白金を析出させる。   Replating of platinum black plating is performed in the following procedure. The working electrode with platinum black plating is pressed against polishing sand in a beaker or the like, and polishing is repeated until the old platinum black disappears and the metal background is exposed. Thereafter, the polishing sand is removed, and the working electrode is further immersed in alcohol or the like and repeatedly cleaned with an ultrasonic cleaner. Then, after the working electrode is dried, the plating operation is started. The plating operation is generally performed as follows. First, a plating solution is put in a plating container (beaker or the like), and the wetted surface (cathode) of at least the working electrode of the electrode is immersed in this plating solution, and the negative electrode of the current generator is connected via a lead wire. On the other hand, a platinum electrode (anode) is separately immersed in the plating solution, and the positive electrode of the current generator is connected via a lead wire. Then, platinum is deposited on the working electrode by passing a current from the current generator between the working electrode and the platinum electrode.

このように、従来、白金メッキ極の感度を復帰させるためには、煩雑な操作が必要とされ、感度復帰操作自体が面倒であるだけではなく、交換用の隔膜、メッキ液等を消費することとなる。   Thus, conventionally, in order to restore the sensitivity of the platinum plating electrode, a complicated operation is required, and the sensitivity restoration operation itself is not only troublesome but also consumes a replacement diaphragm, plating solution, and the like. It becomes.

上述では、特に、溶存水素センサとされる隔膜型センサを例に説明したが、極表面に白金触媒層、白金メッキ層が設けられた隔膜型センサにおいて広く同様の問題がある。   In the above description, the diaphragm type sensor, which is a dissolved hydrogen sensor, has been described as an example. However, the diaphragm type sensor in which the platinum catalyst layer and the platinum plating layer are provided on the extreme surface has the same wide problem.

そのため、極めて容易に、特に、隔膜を取り外すことなく、感度を復帰させることのできる隔膜型センサの感度復帰方法が望まれている。   Therefore, there is a demand for a sensitivity return method for a diaphragm type sensor that can return sensitivity very easily, in particular, without removing the diaphragm.

本発明者の知る限りにおいて、この目的に適う隔膜型センサの感度復帰方法は未だ提案されていない。   As far as the present inventor is aware, no method for returning the sensitivity of the diaphragm type sensor that meets this purpose has been proposed yet.

本発明の目的は、容易に感度を復帰させることのできる隔膜型センサの感度復帰方法、計測装置及び電極再生装置を提供することである。   An object of the present invention is to provide a sensitivity return method, a measuring device, and an electrode regeneration device for a diaphragm type sensor that can easily return the sensitivity.

本発明の他の目的は、隔膜を取り外すことなく、極めて容易に感度を復帰させることのできる隔膜型センサの感度復帰方法、計測装置及び電極再生装置を提供することである。   Another object of the present invention is to provide a sensitivity return method, a measuring device, and an electrode regeneration device for a diaphragm type sensor that can return sensitivity very easily without removing the diaphragm.

本発明の他の目的は、隔膜型センサの交換用隔膜、メッキ液の使用を低減することのできる隔膜型センサの感度復帰方法、計測装置及び電極再生装置を提供することである。   Another object of the present invention is to provide a diaphragm for replacement of a diaphragm type sensor, a sensitivity return method for a diaphragm type sensor that can reduce the use of a plating solution, a measuring device, and an electrode regeneration device.

本発明の他の目的は、感度劣化を低減することのできる隔膜型センサの感度復帰方法、計測装置及び電極再生装置を提供することである。   Another object of the present invention is to provide a sensitivity return method, a measuring device, and an electrode regeneration device for a diaphragm type sensor that can reduce sensitivity deterioration.

上記目的は本発明に係る隔膜型センサの感度復帰方法、計測装置及び電極再生装置にて達成される。要約すれば、第１の本発明は、センサ本体の一端に試料中の測定対象成分を透過させる隔膜が着脱自在であり、前記隔膜によって外部と区画される室の内部に、表面に白金族触媒層又は白金メッキ層が設けられた作用極と、対極と、が配置され、前記作用極と前記対極とが前記室内に収容された電解液に接触した状態で、前記隔膜を透過した測定対象成分が前記作用極の表面で反応することにより前記作用極と対極との間に流れる測定電流を測定するための隔膜型センサの感度復帰方法において、前記作用極に前記測定電流とは異なる感度復帰電流を流すことを特徴とする隔膜型センサの感度復帰方法である。   The above object is achieved by the sensitivity return method, the measuring device and the electrode regeneration device of the diaphragm type sensor according to the present invention. In summary, according to the first aspect of the present invention, a diaphragm for allowing a measurement target component in a sample to pass therethrough is detachable at one end of a sensor body, and a platinum group catalyst is formed on the surface inside a chamber partitioned from the outside by the diaphragm. A measurement target component that has passed through the diaphragm in a state in which a working electrode provided with a layer or a platinum plating layer and a counter electrode are disposed, and the working electrode and the counter electrode are in contact with the electrolytic solution accommodated in the chamber In the sensitivity return method of the diaphragm type sensor for measuring the measurement current flowing between the working electrode and the counter electrode by reacting on the surface of the working electrode, the sensitivity return current different from the measurement current in the working electrode This is a method for returning the sensitivity of the diaphragm type sensor.

第２の本発明によれば、センサ本体の一端に試料中の測定対象成分を透過させる隔膜が着脱自在であり、前記隔膜によって外部と区画される室の内部に、表面に白金族触媒層又は白金メッキ層が設けられた作用極と、対極と、が配置され、前記作用極と前記対極とが前記室内に収容された電解液に接触した状態で、前記隔膜を透過した測定対象成分が前記作用極の表面で反応することにより前記作用極と対極との間に流れる測定電流を測定するための隔膜型センサが接続される計測装置において、
前記作用極に流れる前記測定電流を検出する電流計と、
前記作用極に前記測定電流とは異なる感度復帰電流を流す感度復帰電流発生器と、
を有することを特徴とする計測装置が提供される。第２の本発明の一実施態様によると、前記感度復帰電流発生器は、所定タイミングで自動的に前記作用極に感度復帰電流を流すことができる。 According to the second aspect of the present invention, the diaphragm for allowing the measurement target component in the sample to pass through is detachable at one end of the sensor body, and the platinum group catalyst layer or the surface is formed inside the chamber partitioned from the outside by the diaphragm. A working electrode provided with a platinum plating layer and a counter electrode are disposed, and the component to be measured that has passed through the diaphragm is in a state where the working electrode and the counter electrode are in contact with the electrolytic solution accommodated in the chamber. In a measuring device to which a diaphragm type sensor for measuring a measurement current flowing between the working electrode and the counter electrode by reacting on the surface of the working electrode is connected,
An ammeter for detecting the measurement current flowing through the working electrode;
A sensitivity return current generator for passing a sensitivity return current different from the measurement current to the working electrode;
There is provided a measuring device characterized by comprising: According to an embodiment of the second aspect of the present invention, the sensitivity return current generator can automatically flow the sensitivity return current to the working electrode at a predetermined timing.

第３の本発明によると、センサ本体の一端に試料中の測定対象成分を透過させる隔膜が着脱自在であり、前記隔膜によって外部と区画される室の内部に、表面に白金族触媒層又は白金メッキ層が設けられた作用極と、対極と、が配置され、前記作用極と前記対極とが前記室内に収容された電解液に接触した状態で、前記隔膜を透過した測定対象成分が前記作用極の表面で反応することにより前記作用極と対極との間に流れる測定電流を測定するための隔膜型センサが接続される電極再生装置において、
前記作用極に前記測定電流とは異なる感度復帰電流を流す感度復帰電流発生器を有することを特徴とする電極再生装置が提供される。 According to the third aspect of the present invention, the diaphragm for allowing the measurement target component in the sample to pass through is detachable at one end of the sensor body, and the platinum group catalyst layer or white is formed on the surface inside the chamber partitioned from the outside by the diaphragm. A working electrode provided with a gold plating layer and a counter electrode are arranged, and the component to be measured that has permeated through the diaphragm is in the state in which the working electrode and the counter electrode are in contact with the electrolyte contained in the chamber. In an electrode regeneration apparatus to which a diaphragm type sensor for measuring a measurement current flowing between the working electrode and the counter electrode by reacting on the surface of the electrode is connected,
There is provided an electrode regeneration device comprising a sensitivity return current generator for passing a sensitivity return current different from the measurement current to the working electrode.

本発明の一実施態様によると、前記感度復帰電流の量は、測定時に前記作用極に流れる前記測定電流の量の最大値よりも大きい。好ましい一実施態様によると、前記感度復帰電流の量は、測定時に前記作用極に流れる前記測定電流の最大値の５倍以上である。   According to an embodiment of the present invention, the amount of the sensitivity return current is larger than the maximum value of the amount of the measurement current flowing through the working electrode during measurement. According to a preferred embodiment, the amount of the sensitivity return current is not less than 5 times the maximum value of the measurement current flowing through the working electrode during measurement.

又、本発明の一実施態様によると、前記隔膜を前記センサ本体から取り外すことなく、前記作用極と、前記対極又は前記対極とは別個に前記室内に設けられた内部補助電極と、の間に電圧を印加することにより、前記室内に収容された前記電解液を導電媒体として前記作用極に前記感度復帰電流を流す。他の実施態様では、前記隔膜を前記センサ本体から取り外し、前記作用極と、前記対極、前記対極とは別個に前記室内に設けられた内部補助電極又は前記隔膜型センサとは別個の外部補助電極と、を導電媒体中に浸漬して、前記作用極と、前記対極、前記内部補助電極又は前記外部補助電極と、の間に電圧を印加することにより前記作用極に前記感度復帰電流を流す。前記感度復帰電流として、前記作用極に、正極性又は負極性の直流電流を流すことができる。又、前記感度復帰電流として、前記作用極に、正極性及び負極性の直流電流を交互に流すか、又は、交流電流を流すことができる。   According to an embodiment of the present invention, the working electrode and the counter electrode or the internal auxiliary electrode provided in the chamber separately from the counter electrode without removing the diaphragm from the sensor body. By applying a voltage, the sensitivity return current is caused to flow through the working electrode using the electrolyte contained in the chamber as a conductive medium. In another embodiment, the diaphragm is removed from the sensor body, and the working electrode, the counter electrode, an internal auxiliary electrode provided in the chamber separately from the counter electrode, or an external auxiliary electrode separate from the diaphragm sensor Are immersed in a conductive medium, and a voltage is applied between the working electrode and the counter electrode, the internal auxiliary electrode, or the external auxiliary electrode to cause the sensitivity return current to flow through the working electrode. As the sensitivity return current, a positive or negative direct current can be passed through the working electrode. Further, as the sensitivity return current, positive and negative direct currents can be alternately supplied to the working electrode, or an alternating current can be supplied.

前記隔膜型センサは、ポーラログラフ式センサ又はガルバニ電池式センサであってよい。又、前記隔膜型センサは、水素ガスセンサ又は溶存水素センサであってよい。更に、前記白金メッキ層として、白金黒メッキの層又は灰色を呈する白金メッキ層を有していてよい。   The diaphragm type sensor may be a polarographic sensor or a galvanic cell sensor. The diaphragm type sensor may be a hydrogen gas sensor or a dissolved hydrogen sensor. Further, as the platinum plating layer, a platinum black plating layer or a gray platinum plating layer may be provided.

本発明によれば、隔膜型センサの感度を容易に復帰させることができる。又、本発明によれば、隔膜型センサの隔膜を取り外すことなく、極めて容易にその感度を復帰させることができる。又、本発明によれば、隔膜型センサの交換用隔膜、メッキ液の使用を低減することができる。更に、本発明によれば、隔膜型センサの感度劣化を低減することができる。   According to the present invention, the sensitivity of the diaphragm type sensor can be easily restored. Further, according to the present invention, the sensitivity can be restored very easily without removing the diaphragm of the diaphragm type sensor. Further, according to the present invention, it is possible to reduce the use of a replacement diaphragm for the diaphragm type sensor and a plating solution. Furthermore, according to the present invention, it is possible to reduce the sensitivity deterioration of the diaphragm type sensor.

以下、本発明に係る隔膜型センサの感度復帰方法、計測装置及び電極再生装置を図面に則して更に詳しく説明する。   Hereinafter, a sensitivity return method, a measuring device, and an electrode regeneration device for a diaphragm type sensor according to the present invention will be described in more detail with reference to the drawings.

実施例１
本実施例では、本発明は、図１を参照して先に説明したものと基本的に同一の隔膜型センサ１０Ａを備える計測装置１００にて具現化される。つまり、本実施例の計測装置１００は、隔膜型ポーラログラフ式の溶存水素センサとされる隔膜型センサ１０Ａと、隔膜型センサ１０Ａが接続されて信号処理を行う計測器（計測装置本体）２０とを有する溶存水素計である。 Example 1
In the present embodiment, the present invention is embodied in a measuring apparatus 100 including a diaphragm type sensor 10A that is basically the same as that described above with reference to FIG. That is, the measurement apparatus 100 of the present embodiment includes a diaphragm type sensor 10A that is a diaphragm type polarographic type dissolved hydrogen sensor, and a measuring instrument (measurement apparatus body) 20 that is connected to the diaphragm type sensor 10A and performs signal processing. It has a dissolved hydrogen meter.

先ず、計測装置１００の全体構成について説明する。隔膜型センサ１０Ａは、中空円筒状のセンサ本体１１と、その先端開口部に固定されたガス透過性隔膜１３と、この隔膜１３に近接してセンサ本体１１の内部に配置された作用極１４と、この作用極１４を支持する支持管１６と、支持管１６の内方外周部に取り付けられた対極１５とを備えている。センサ本体１１と支持管１６との間には隔膜１３によって外部と区画された室１１ａが形成され、この室１１ａ内に電解液１７が収容される。   First, the overall configuration of the measuring apparatus 100 will be described. The diaphragm type sensor 10 </ b> A includes a hollow cylindrical sensor body 11, a gas permeable diaphragm 13 fixed to the opening at the tip thereof, and a working electrode 14 disposed inside the sensor body 11 in the vicinity of the diaphragm 13. The support tube 16 that supports the working electrode 14 and the counter electrode 15 that is attached to the inner periphery of the support tube 16 are provided. A chamber 11a that is partitioned from the outside by the diaphragm 13 is formed between the sensor body 11 and the support tube 16, and the electrolyte solution 17 is accommodated in the chamber 11a.

例えばガラスにて作製された支持管１６は、センサ内部に同軸的に配設され、その先端に上記作用極１４が取り付けられている。隔膜１３と作用極１４との間には厚さが一定の僅かな間隙が形成され、一定の厚さの電解液１７の層（電解液層）を形成している。   For example, the support tube 16 made of glass is coaxially disposed inside the sensor, and the working electrode 14 is attached to the tip thereof. A slight gap having a constant thickness is formed between the diaphragm 13 and the working electrode 14 to form a layer (electrolyte layer) of the electrolyte 17 having a constant thickness.

本実施例では、作用極１４は白金で形成され、その接液表面には白金メッキ層Ｐが設けられる。本発明は、白金メッキ層Ｐとしては、極の活性を上げ、感度劣化を抑制するように極に施される任意の白金メッキであってよい。本実施例では、白金メッキ層Ｐとしては、従来一般に使用されている白金黒メッキを使用する。対極１５は銀−塩化銀（Ａｇ／ＡｇＣｌ）で形成される。又、電解液１７としては、０．１ｍｏｌ／Ｌ ＨＣｌ＋０．１ｍｏｌ／Ｌ ＫＣｌを好適に用い得る。   In the present embodiment, the working electrode 14 is made of platinum, and a platinum plating layer P is provided on the liquid contact surface thereof. In the present invention, the platinum plating layer P may be any platinum plating applied to the electrode so as to increase the activity of the electrode and suppress the sensitivity deterioration. In the present embodiment, as the platinum plating layer P, platinum black plating that is generally used conventionally is used. The counter electrode 15 is formed of silver-silver chloride (Ag / AgCl). Further, as the electrolytic solution 17, 0.1 mol / L HCl + 0.1 mol / L KCl can be suitably used.

作用極１４及び対極１５にはそれぞれリード線１４ａ及び１５ａが接続され、これらリード線１４ａ、１５ａは支持管１６内を通って外部に導出され、計測器２０が備える電源回路２１に接続されている。そして、この作用極１４と対極１５との間に、リード線１４ａ及び１５ａを介して、電源回路２１（図２）が備える第１の電圧印加手段（電流発生器）としての測定用電源（直流電源）２１ａから所定の電解電圧を連続して印加する。そして、電解電流の定常値を電流計２２にて測定することによって試料溶液中の溶存ガス濃度を求めている。つまり、隔膜１３を透過した測定対象ガス（ここでは、水素ガス）は、作用極１４の面で反応し、そのとき作用極１４に流れる溶存ガスの電解電流（測定電流）が電流計２２で測定され、隔膜型センサ１０Ａで検出した溶存水素濃度を計測するように構成されている。計測結果は計測器２０に設けた指示計より水素濃度などに変換されて表示（指示）される。或いは、計測結果は、計測器２０が備えるか計測器２０と通信可能に接続されたプリンタによりプリントアウトしてもよい。   Lead wires 14 a and 15 a are connected to the working electrode 14 and the counter electrode 15, respectively. These lead wires 14 a and 15 a are led out through the support tube 16 and connected to a power supply circuit 21 provided in the measuring instrument 20. . A power supply for measurement (DC) as a first voltage applying means (current generator) included in the power supply circuit 21 (FIG. 2) is provided between the working electrode 14 and the counter electrode 15 via lead wires 14a and 15a. A predetermined electrolytic voltage is continuously applied from the power source 21a. And the dissolved gas concentration in a sample solution is calculated | required by measuring the steady value of an electrolysis current with the ammeter 22. FIG. That is, the measurement target gas (here, hydrogen gas) that has passed through the diaphragm 13 reacts on the surface of the working electrode 14, and the electrolysis current (measurement current) of the dissolved gas flowing through the working electrode 14 at that time is measured by the ammeter 22. The dissolved hydrogen concentration detected by the diaphragm type sensor 10A is measured. The measurement result is converted into a hydrogen concentration or the like from an indicator provided in the measuring instrument 20 and displayed (instructed). Alternatively, the measurement result may be printed out by a printer that is included in the measuring instrument 20 or that is communicably connected to the measuring instrument 20.

隔膜１３は、センサ本体１１に対して着脱自在に取り付けられている。又、隔膜型センサ１０Ａは、リード線１４ａ、１５ａを介して計測器２０に対し着脱自在に接続されている。   The diaphragm 13 is detachably attached to the sensor body 11. The diaphragm type sensor 10A is detachably connected to the measuring instrument 20 through lead wires 14a and 15a.

次に、本発明の一態様である隔膜型センサの感度復帰方法について説明する。   Next, a sensitivity return method for the diaphragm sensor according to one embodiment of the present invention will be described.

本発明の感度復帰方法は、感度復帰操作時に、測定時に作用極１４に流れる測定電流とは異なる感度復帰電流を作用極１４に流すことを含む。本実施例では、感度復帰操作は、操作者が、隔膜型センサ１０Ａの感度が劣化したことを認知した際、或いは定期的に実施することができる。   The sensitivity recovery method of the present invention includes flowing a sensitivity recovery current to the working electrode 14 that is different from the measurement current flowing to the working electrode 14 during measurement during the sensitivity recovery operation. In this embodiment, the sensitivity return operation can be performed when the operator recognizes that the sensitivity of the diaphragm type sensor 10A has deteriorated or periodically.

感度復帰電流は、正極性、負極性のいずれの電流であってもよい。典型的には、感度復帰電流として、正極性、負極性のいずれかの直流電流を好ましく用いることができる。ここで、作用極１４に流れる電流に関して正極性とは、還元体から電極への電子移動方向（酸化電流）をいい、又、負極性とは、電極から酸化体への電子移動方向（還元電流）をいう。   The sensitivity return current may be either positive or negative current. Typically, either positive or negative direct current can be preferably used as the sensitivity recovery current. Here, with respect to the current flowing through the working electrode 14, the positive polarity refers to the direction of electron transfer (oxidation current) from the reductant to the electrode, and the negative polarity refers to the direction of electron transfer from the electrode to the oxidant (reduction current). ).

本発明が好適に作用するメカニズムについては、完全に解明するに到っていないが、本発明者らの検討によれば、吸蔵等による白金メッキ層Ｐの化学的な汚れが、作用極１４に電流を流すことによって電解洗浄されるものと考えられる。   Although the mechanism by which the present invention suitably works has not been fully elucidated, according to the study by the present inventors, chemical contamination of the platinum plating layer P due to occlusion or the like is caused on the working electrode 14. It is considered that electrolytic cleaning is performed by passing an electric current.

先ず、感度復帰電流として直流を用いる場合について更に説明すると、感度復帰電流の量（値）は、測定時に作用極１４に流れる測定電流の量の最大値よりも大きくする。感度復帰電流の量は、好ましくは、測定時に作用極１４に流れる測定電流の最大値の５倍以上とすることによって、顕著な感度復帰効果を得ることができる。より好ましくは、１０倍以上、更に好ましくは２０倍以上とする。   First, the case of using DC as the sensitivity return current will be further described. The amount (value) of the sensitivity return current is set to be larger than the maximum value of the amount of measurement current flowing through the working electrode 14 during measurement. The amount of the sensitivity return current is preferably set to 5 times or more the maximum value of the measurement current flowing through the working electrode 14 during measurement, whereby a remarkable sensitivity return effect can be obtained. More preferably, it is 10 times or more, more preferably 20 times or more.

但し、感度復帰電流の量が、測定時に作用極１４に流れる測定電流の最大値の１０００倍より大きいと、極の表面状態が安定するまでに時間がかかり好ましくない。そのため、好ましくは感度復帰電流の量は、測定時に作用極１４に流れる測定電流の最大値の１０００倍以下とする。より好ましくは、１００倍以下とする。   However, if the amount of the sensitivity return current is larger than 1000 times the maximum value of the measurement current flowing through the working electrode 14 at the time of measurement, it takes time to stabilize the surface state of the electrode, which is not preferable. For this reason, the amount of sensitivity return current is preferably 1000 times or less the maximum value of the measurement current flowing through the working electrode 14 during measurement. More preferably, it is 100 times or less.

従って、感度復帰電流の量は、測定時に作用極１４に流れる測定電流の５倍〜１０００倍が好ましい。より好ましくは感度復帰電流の量は、測定時に作用極１４に流れる測定電流の１０倍〜１０００倍、更に好ましくは２０倍〜１００倍である。   Therefore, the amount of the sensitivity return current is preferably 5 to 1000 times the measurement current flowing through the working electrode 14 during measurement. More preferably, the amount of sensitivity return current is 10 to 1000 times, more preferably 20 to 100 times the measurement current flowing through the working electrode 14 during measurement.

感度復帰電流の極性は、感度復帰操作中に変更してもよい。この場合、いずれかの極性の電流の量が上記範囲内にあればよい。例えば、正極性、負極性の直流電流を交互に流したり、第１の期間だけ正極性の直流電流を流した後、この第１の期間と同じか若しくは異なる（長い若しくは短い）第２の期間だけ負極性の直流電流を流すことができる。つまり、正極性の電流を（１）、負極性の電流を（２）として、（１）＋（２）、（１）＋（２）＋（１）、或いは（１）＋（２）の繰り返しなどとすることができる。   The polarity of the sensitivity recovery current may be changed during the sensitivity recovery operation. In this case, the amount of current of either polarity may be in the above range. For example, after a positive DC current and a negative DC current are alternately flowed, or a positive DC current is passed only during the first period, the second period is the same as or different from (long or short) the first period. Only negative DC current can flow. That is, assuming that the positive current is (1) and the negative current is (2), (1) + (2), (1) + (2) + (1), or (1) + (2) It can be repeated.

更に、感度復帰操作時に、作用極１４に流す電流として交流を用いることもできる。交流波形は特に限定されず、正弦波、矩形波などを適宜用いることができる。又、交流周波数も適宜選定することができるが、典型的には、直流から商用周波数（５０／６０Ｈｚ）までを好適に用いることができる。   Furthermore, alternating current can also be used as a current flowing through the working electrode 14 during the sensitivity recovery operation. The AC waveform is not particularly limited, and a sine wave, a rectangular wave, or the like can be used as appropriate. Moreover, although an alternating frequency can also be selected suitably, typically, DC to a commercial frequency (50/60 Hz) can be used conveniently.

本発明の好ましい一実施態様によれば、隔膜型センサ１０Ａの隔膜１３をセンサ本体１１から取り外すことなく、感度復帰操作を実施することができる。この場合、隔膜型センサ１０Ａの室１１ａ内にある作用極１４と対極１５との間に電圧を印加することができる。又、この場合、導電媒体としては、室１１ａ内に通常収容されている電解液１７を用いることができる。   According to a preferred embodiment of the present invention, the sensitivity return operation can be performed without removing the diaphragm 13 of the diaphragm type sensor 10 </ b> A from the sensor body 11. In this case, a voltage can be applied between the working electrode 14 and the counter electrode 15 in the chamber 11a of the diaphragm type sensor 10A. In this case, as the conductive medium, the electrolytic solution 17 that is normally accommodated in the chamber 11a can be used.

上述の本発明に係る隔膜型センサの感度復帰方法は、例えば、隔膜型センサ１０Ａに対して、機能上十分な電流発生器を接続することによって達成することができる。本発明の他の態様では、本発明に係る隔膜型センサの感度復帰方法をより容易に具現化し得る計測装置が提供される。   The above-described sensitivity return method of the diaphragm type sensor according to the present invention can be achieved, for example, by connecting a functionally sufficient current generator to the diaphragm type sensor 10A. In another aspect of the present invention, there is provided a measuring apparatus that can more easily embody the sensitivity return method of the diaphragm type sensor according to the present invention.

次に、本発明に係る隔膜型センサの感度復帰方法を具現化する計測装置１００について更に説明する。   Next, the measuring apparatus 100 that embodies the sensitivity return method of the diaphragm type sensor according to the present invention will be further described.

図２は、隔膜を取り外すことなく感度復帰操作を行い得る計測装置１００の一実施例の概略機能ブロックを示す。本実施例では、計測装置１００は、特に、隔膜型センサ１０Ａを計測器２０に対して着脱することなく、通常の測定操作の他に、感度復帰操作を行い得るようになっている。   FIG. 2 shows a schematic functional block of an embodiment of the measuring apparatus 100 that can perform the sensitivity return operation without removing the diaphragm. In the present embodiment, the measurement apparatus 100 can perform a sensitivity return operation in addition to a normal measurement operation without attaching / detaching the diaphragm type sensor 10 </ b> A to the measuring instrument 20.

図示の通り、計測装置１００は、隔膜型センサ１０Ａと、計測器２０とを有する。計測器２０は、電源回路２１を有している。この電源回路２１は、測定時に隔膜型センサ１０Ａの作用極１４と対極１５との間に電圧（測定電圧）を印加するための第１の電圧印加手段（電流発生器）としての測定用電源２１ａと、感度復帰操作時に隔膜型センサ１０Ａの作用極１４に感度復帰電流を生起させるべく作用極１４と対極１５との間に電圧（感度復帰電圧）を印加するための第２の電圧印加手段（電流発生器）としての感度復帰用電源２１ｂとを有する。又、電源回路２１は、隔膜型センサ１０Ａの作用極１４と対極１５との間に介装され、作用極１４と対極１５との間に、測定用電源２１ａ、感度復帰用電源２１ｂから選択的に測定電圧、感度復帰電圧を印加させる切替手段としての切替器２１ｃが設けられている。   As illustrated, the measuring device 100 includes a diaphragm type sensor 10 </ b> A and a measuring instrument 20. The measuring instrument 20 has a power supply circuit 21. The power supply circuit 21 is a measurement power supply 21a as a first voltage application means (current generator) for applying a voltage (measurement voltage) between the working electrode 14 and the counter electrode 15 of the diaphragm type sensor 10A during measurement. And a second voltage applying means for applying a voltage (sensitivity return voltage) between the working electrode 14 and the counter electrode 15 so as to generate a sensitivity return current in the working electrode 14 of the diaphragm type sensor 10A during the sensitivity returning operation ( And a power supply 21b for returning sensitivity as a current generator. The power supply circuit 21 is interposed between the working electrode 14 and the counter electrode 15 of the diaphragm type sensor 10A, and is selectively selected from the measuring power supply 21a and the sensitivity return power supply 21b between the working electrode 14 and the counter electrode 15. A switching device 21c is provided as switching means for applying a measurement voltage and a sensitivity return voltage to the sensor.

又、計測器２０は、電流計の計測結果を水素濃度表示などに変換して表示（指示）する指示計２４を有する。更に、計測器２０は、測定の開始／停止、感度復帰操作の開始／停止の指示、或いは種々の設定値等の入力を行うための入力手段、表示手段等を備える操作部２３を有する。   The measuring instrument 20 also has an indicator 24 that converts (displays) the measurement result of the ammeter into a hydrogen concentration display or the like. Furthermore, the measuring instrument 20 includes an operation unit 23 that includes an input unit, a display unit, and the like for inputting measurement start / stop, a start / stop instruction for a sensitivity return operation, or various setting values.

本実施例によると、切替器２１ｃは、操作者の操作部２３からの操作に応じて、作用極１４と対極１５とを、測定用電源２１ａ又は感度復帰用電源２１ｂのいずれかに選択的に接続するようになっている。   According to the present embodiment, the switch 21c selectively selects the working electrode 14 and the counter electrode 15 as either the measurement power supply 21a or the sensitivity return power supply 21b in accordance with the operation from the operation unit 23 by the operator. It comes to connect.

そして、本実施例では、操作者の操作部２３からの操作により感度回復操作の開始が指示されると、感度復帰用電源２１ｂは、作用極１４に所定の感度復帰電流が流れるように、作用極１４と対極１５との間に感度復帰電圧を印加する。感度復帰電流は、所望の感度復帰効果を得るのに十分なように予め設定された所定時間の経過後に、再び操作者による操作部２３からの操作により停止するようにしてもよいが、予め設定された所定時間後に自動的に停止するように電源回路２１を構成することができる。   In this embodiment, when the start of the sensitivity recovery operation is instructed by an operation from the operation unit 23 by the operator, the sensitivity return power supply 21b operates so that a predetermined sensitivity return current flows through the working electrode 14. A sensitivity return voltage is applied between the pole 14 and the counter electrode 15. The sensitivity return current may be stopped again by an operation from the operation unit 23 by the operator after the elapse of a predetermined time set in advance so as to be sufficient to obtain a desired sensitivity return effect. The power supply circuit 21 can be configured to automatically stop after a predetermined time.

斯かる構成により、操作者は、センサ本体１１から隔膜１３を取り外すことなく、操作部２３から感度復帰操作を指示することによって、極めて簡単に隔膜型センサ１０Ａの感度復帰操作を実施することができる。   With this configuration, the operator can perform the sensitivity return operation of the diaphragm type sensor 10 </ b> A very easily by instructing the sensitivity return operation from the operation unit 23 without removing the diaphragm 13 from the sensor body 11. .

特に、本発明の隔膜型センサの感度復帰方法によれば、作用極１４から古い白金メッキ層Ｐを除去して、白金メッキ層Ｐを再メッキする等の操作を行うことなく、極めて簡単に感度を復帰させることができる。これにより、隔膜型センサ１０Ａの感度を極めて簡単に復帰させることができるばかりか、交換用の隔膜の消費を飛躍的に低減することができ、又再メッキに使用するメッキ液などの試薬も不要となる。   In particular, according to the sensitivity return method of the diaphragm type sensor of the present invention, it is very easy to remove the old platinum plating layer P from the working electrode 14 and re-plating the platinum plating layer P. Can be restored. As a result, the sensitivity of the diaphragm type sensor 10A can be restored very easily, the consumption of the replacement diaphragm can be drastically reduced, and a reagent such as a plating solution used for re-plating is unnecessary. It becomes.

尚、上述では、隔膜型センサ１０Ａの室１１ａ内に配置された作用極１４と対極１５との間に感度復帰電圧を印加して、作用極１４に感度復帰電流を印加する場合について説明した。斯かる実施態様によれば、感度復帰操作のために、隔膜型センサ１０Ａに特別な部材を追加する必要がなく、隔膜型センサ１０Ａの構成の簡易化等の点で極めて有利であるが、本発明はこれに限定されるものではない。   In the above description, the case where the sensitivity return voltage is applied between the working electrode 14 and the counter electrode 15 disposed in the chamber 11a of the diaphragm type sensor 10A and the sensitivity return current is applied to the working electrode 14 has been described. According to such an embodiment, there is no need to add a special member to the diaphragm type sensor 10A for sensitivity return operation, and this is extremely advantageous in terms of simplification of the configuration of the diaphragm type sensor 10A. The invention is not limited to this.

別法として、図３に示すように、室１１ａ内に、対極１５とは別に、内部補助電極１８を設けることができる。内部補助電極１８は、リード線１８ａが接続され、このリード線１８ａが隔膜型センサ１０Ａの外部に導出されて、計測器２０が備える電源回路２１に接続される。この場合、図３に示すように、計測器２０の電源回路２１は、測定時に作用極１４と対極１５との間に測定電圧を印加する測定用電源２１ａと、感度復帰操作において作用極１４と内部補助電極１８との間に感度復帰電圧を印加する感度復帰用電源２１ｂと、切替器２１ｃとを有する。そして、図２を参照して上述した、作用極１４と対極１５との間に感度復帰電圧を印加する場合と概略同様にして、感度復帰操作時に作用極１４と内部補助電極１８との間に感度復帰電圧を印加することができる。つまり、感度復帰操作時に、切替器２１ｃは、作用極１４と内部補助電極１８とを感度復帰用電源２１ｂに接続して、作用極１４と内部補助電極１８との間に感度復帰時電圧を印加し、作用極１４に感度復帰電流を流す。   Alternatively, as shown in FIG. 3, an internal auxiliary electrode 18 can be provided in the chamber 11 a separately from the counter electrode 15. The internal auxiliary electrode 18 is connected to a lead wire 18a. The lead wire 18a is led out of the diaphragm type sensor 10A and connected to a power supply circuit 21 provided in the measuring instrument 20. In this case, as shown in FIG. 3, the power supply circuit 21 of the measuring instrument 20 includes a measurement power supply 21 a that applies a measurement voltage between the working electrode 14 and the counter electrode 15 during measurement, and a working electrode 14 in the sensitivity recovery operation. A sensitivity recovery power source 21b for applying a sensitivity recovery voltage to the internal auxiliary electrode 18 and a switch 21c are provided. Then, in the same manner as in the case of applying the sensitivity return voltage between the working electrode 14 and the counter electrode 15 described above with reference to FIG. 2, between the working electrode 14 and the internal auxiliary electrode 18 during the sensitivity returning operation. A sensitivity return voltage can be applied. That is, at the time of the sensitivity return operation, the switch 21c connects the working electrode 14 and the internal auxiliary electrode 18 to the sensitivity return power source 21b, and applies the voltage at the time of sensitivity return between the working electrode 14 and the internal auxiliary electrode 18. Then, a sensitivity return current is passed through the working electrode 14.

又、説明のため、図２、図３においては、電源回路２１が備える測定用電源２１ａと感度復帰用電源２１ｂとは、機能的に分離して示しているが、これらが実質的に単一の電源回路として構成されていてもよい。この場合、切替器２１ｃは、その電源回路から作用極１４と対極１５に印加する電圧を変更する手段として機能する（或いは、作用極１４と対極１５との間に測定電圧を印加し、作用極１４と内部補助電極１８との間に感度復帰電圧を印加する切替及び電圧変更手段として機能する）。   For the sake of explanation, in FIGS. 2 and 3, the measurement power supply 21a and the sensitivity recovery power supply 21b included in the power supply circuit 21 are functionally separated from each other. It may be configured as a power supply circuit. In this case, the switch 21c functions as means for changing the voltage applied from the power supply circuit to the working electrode 14 and the counter electrode 15 (or, by applying a measurement voltage between the working electrode 14 and the counter electrode 15, 14 and the auxiliary auxiliary electrode 18 function as switching and voltage changing means for applying a sensitivity return voltage).

以上、本実施例によれば、容易に隔膜型センサ１０Ａの感度を復帰させることができる。特に、本実施例によれば、隔膜型センサ１０Ａの隔膜１３を取り外すことなく、その感度を、極めて容易に復帰させることができる。そして、隔膜型センサ１０の感度復帰のために隔膜１３の交換、再メッキの必要がないので、交換用隔膜、メッキ液の使用を飛躍的に低減することができる。   As described above, according to this embodiment, the sensitivity of the diaphragm type sensor 10A can be easily restored. In particular, according to the present embodiment, the sensitivity can be restored very easily without removing the diaphragm 13 of the diaphragm type sensor 10A. In addition, since it is not necessary to replace and replate the diaphragm 13 in order to restore the sensitivity of the diaphragm sensor 10, it is possible to dramatically reduce the use of the replacement diaphragm and the plating solution.

実施例２
次に、本発明の他の実施例について説明する。尚、上記実施例の計測装置１００と実質的に同一又は相当する構成、機能を有する要素には同一符号を付し、詳しい説明は省略する。 Example 2
Next, another embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the element which has the structure and function substantially equivalent or equivalent to the measuring apparatus 100 of the said Example, and detailed description is abbreviate | omitted.

実施例１では、隔膜型センサの極に従来の白金黒メッキが施されている場合について説明した。   In Example 1, the case where the conventional platinum black plating was given to the pole of the diaphragm type sensor was demonstrated.

前述のように、極表面に白金黒メッキを行い、極の表面活性を上げることにより、感度劣化を軽減することが可能である。しかし、白金黒メッキは、粉状に付着した金属微粒子であり、脆弱で取れ易く、隔膜型電極では非常に扱い難い性状である。又、物理的汚れの除去も困難であり、メッキが取れた時に、感度低下を起こす虞がある。   As described above, it is possible to reduce the sensitivity deterioration by performing platinum black plating on the electrode surface to increase the surface activity of the electrode. However, platinum black plating is fine metal particles adhering to the powder, is fragile and easy to remove, and is very difficult to handle with a diaphragm electrode. In addition, it is difficult to remove physical stains, and there is a possibility that the sensitivity is lowered when the plating is removed.

ところで、特開平９−１３８２１５号公報は、高濃度の水素を計測したり、連続的に計測を行う場合に、経時的に感度が低下したり、ドリフトしたりすることがないように、スパッタリングや真空蒸着などにより、白金触媒薄層を隔膜に形成し、反応部分を一体化させて安定な計測を行うことが開示されている。しかしながら、このような方法でも、感度劣化をゼロとすることは困難であり、又、感度劣化した場合に感度を復帰させることは容易でない。   By the way, Japanese Patent Laid-Open No. 9-138215 discloses a sputtering method so that the sensitivity does not decrease over time or drifts when high concentration hydrogen is measured or continuously measured. It is disclosed that a platinum catalyst thin layer is formed on a diaphragm by vacuum deposition or the like, and the reaction parts are integrated to perform stable measurement. However, even with such a method, it is difficult to make the sensitivity degradation zero, and it is not easy to restore the sensitivity when the sensitivity is degraded.

本出願人は、先に、従来の白金黒メッキと同等若しくはそれ以上の極表面の活性を維持していると共に、感度低下が抑制され、又、物理的強度が向上した白金メッキ層を提案した。斯かる白金メッキ層は、灰色を呈する。   The present applicant has previously proposed a platinum plating layer that maintains the surface activity equal to or higher than that of the conventional platinum black plating, suppresses the decrease in sensitivity, and improves the physical strength. . Such a platinum plating layer is gray.

更に説明すると、本発明者らは、先に、メッキ条件によって、作用極１４に設ける白金メッキ層Ｐの触媒機能を維持しながら、白金メッキ層Ｐの状態を変える方法を提案した。   More specifically, the present inventors have previously proposed a method of changing the state of the platinum plating layer P while maintaining the catalytic function of the platinum plating layer P provided on the working electrode 14 according to the plating conditions.

図７は、灰色を呈する白金メッキ層Ｐを作用極４に設けるメッキ装置の概略構成を示している。灰色を呈する白金メッキ方法は、基本的には、従来の白金黒メッキ方法と同様であり、メッキ条件として電流の条件が異なる。即ち、メッキ操作において、先ず、メッキ容器（ビーカーなど）４０内にメッキ液４１を入れ、このメッキ液４１に隔膜型センサ１０Ａの少なくとも作用極１４の接液表面（カソード）を浸漬し、電流発生器３０の負極をリード線１４ａを介して接続する。一方、メッキ液４１に白金極（アノード）を浸漬し、リード線３１ａを介して電流発生器３０の正極を接続する。そして、作用極１４と白金極３１との間に、詳しくは後述するようにして電流発生器３０から電流を流すことによって、作用極１４に白金を析出させる。   FIG. 7 shows a schematic configuration of a plating apparatus in which the gray platinum plating layer P is provided on the working electrode 4. The gray platinum plating method is basically the same as the conventional platinum black plating method, and the current conditions are different as plating conditions. That is, in the plating operation, first, a plating solution 41 is put in a plating container (beaker or the like) 40, and at least the liquid contact surface (cathode) of the diaphragm type sensor 10A is immersed in the plating solution 41 to generate current. The negative electrode of the vessel 30 is connected via the lead wire 14a. On the other hand, a platinum electrode (anode) is immersed in the plating solution 41, and the positive electrode of the current generator 30 is connected via the lead wire 31a. Then, platinum is deposited on the working electrode 14 by flowing a current from the current generator 30 between the working electrode 14 and the platinum electrode 31 as will be described in detail later.

そして、図８に概念図を示すように、概して、メッキ操作における電流を、従来の白金黒メッキ方法よりも、小電流で、長時間流すようにすることにより、本発明に従う灰色を呈する白金メッキ層Ｐを作用極１４上に設けることができる。斯かる白金メッキ層Ｐは、取れ難く、物理的強度も有しており、隔膜型センサ１０Ａの感度低下が抑制される。但し、図８の概念図に示すように、メッキする際の電流を、過度に小電流で、長時間とすると、白金メッキ層Ｐは白色を呈するようになり、触媒活性を維持し得なくなる。   Then, as shown in the conceptual diagram of FIG. 8, generally, the platinum plating exhibiting a gray color according to the present invention is performed by causing the current in the plating operation to flow for a longer time with a smaller current than in the conventional platinum black plating method. The layer P can be provided on the working electrode 14. Such a platinum plating layer P is difficult to remove and has physical strength, and a decrease in sensitivity of the diaphragm type sensor 10A is suppressed. However, as shown in the conceptual diagram of FIG. 8, if the current during plating is excessively small and long, the platinum plating layer P becomes white, and the catalytic activity cannot be maintained.

図９及び図１０をも参照して更に説明すると、メッキ操作における電流の単位時間当たりの電流密度が小さくなるほど、析出した白金結晶の表面は、ざらざらした粗い針状の結晶から、金属粒子の結合した滑らかな状態へと変化する。   Further explanation will be given with reference to FIG. 9 and FIG. 10 as the current density per unit time of the current in the plating operation becomes smaller, the surface of the deposited platinum crystal becomes more bonded to the metal particles from the rough and coarse needle-like crystals. To a smooth state.

図９及び図１０は、メッキ条件として電流条件を変化させた際の白金メッキ層Ｐの表面を走査型電子顕微鏡（ＳＥＭ）で観察した結果を示す。即ち、従来の白金黒メッキは、図９（ａ）に示すように、略針状の細かく析出した白金結晶の塊（外径が約１〜３μｍ）を生成する。そして、単位時間当たりの電流密度を小さくなるに従って、図９（ｂ）、図９（ｃ）に示すように、より成長した大きな白金結晶の塊（概略略５〜１５μｍ）が生成するようになる。更に単位時間当たりの電流密度を小さくすると、図１０（ａ）に示すように、析出した白金結晶の塊はさらに成長した大きなものとなり（外径５〜２０μｍ）、表面は滑らかな状態へと近づく。   9 and 10 show the results of observing the surface of the platinum plating layer P with a scanning electron microscope (SEM) when the current condition is changed as the plating condition. That is, as shown in FIG. 9A, the conventional platinum black plating produces a substantially acicular finely-plated platinum crystal lump (the outer diameter is about 1 to 3 μm). As the current density per unit time becomes smaller, larger platinum crystal lumps (generally about 5 to 15 μm) that have grown as shown in FIGS. 9B and 9C are generated. . When the current density per unit time is further reduced, as shown in FIG. 10 (a), the deposited platinum crystal lump further grows large (outer diameter 5 to 20 μm), and the surface approaches a smooth state. .

しかし、図１０（ｂ）及び図１０（ｃ）に示すように、更に単位時間当たりの電流密度を小さくすると、析出した白金結晶は、粒子状とはならず、より滑らかな略一様な状態となる。   However, as shown in FIGS. 10 (b) and 10 (c), when the current density per unit time is further reduced, the precipitated platinum crystals do not become particles and are in a smoother, substantially uniform state. It becomes.

このとき、作用極４の表面の白金メッキ層Ｐの外観は、図９（ａ）に示す状態では黒色を呈し、図９（ｂ）、図９（ｃ）、図１０（ａ）に示す状態では灰色を呈し、図１０（ｂ）、図１０（ｃ）に示す状態では白色を呈する。   At this time, the appearance of the platinum plating layer P on the surface of the working electrode 4 is black in the state shown in FIG. 9A, and is in the state shown in FIGS. 9B, 9C, and 10A. Shows gray, and in the state shown in FIGS. 10B and 10C, white.

白金メッキ電極の表面が灰色（グレー）を呈している範囲において、堅牢で、且つ、感度低下し難い理想的な電極となる。白金メッキ電極の表面が黒色であるもの、即ち、白金黒電極は、脆弱で取れ易い。一方、白金メッキ電極が白色となると、平滑な白金と同等となり、触媒活性が得られないため、感度が低下する。ここで、白金メッキ層Ｐの外観に関し灰色とは、一般の色概念において灰色とされるものは含まれる。より詳細には、本発明者の検討によれば、マンセル表色系でＮ（無彩色）２．０〜Ｎ８．０で表される色を呈する白金メッキ層Ｐが好適であり、より好ましくはＮ３．０〜Ｎ５．０、更に好ましくはＮ３．０で表される色を呈する白金メッキ層Ｐである。   In the range where the surface of the platinum-plated electrode is gray (gray), it is an ideal electrode that is robust and difficult to decrease in sensitivity. A platinum-plated electrode having a black surface, that is, a platinum black electrode is fragile and easy to remove. On the other hand, when the platinum-plated electrode is white, it becomes equivalent to smooth platinum and the catalytic activity cannot be obtained, so the sensitivity is lowered. Here, with respect to the appearance of the platinum plating layer P, the term “gray” includes those that are gray in a general color concept. More specifically, according to the study of the present inventor, a platinum plating layer P exhibiting a color represented by N (achromatic color) 2.0 to N8.0 in the Munsell color system is suitable, more preferably A platinum plating layer P exhibiting a color represented by N3.0 to N5.0, more preferably N3.0.

上述のように、本発明に従う白金メッキ方法は、下記の電流条件を除けば従来の白金黒メッキ方法と同様である。   As described above, the platinum plating method according to the present invention is the same as the conventional platinum black plating method except for the following current conditions.

メッキ液としては、従来の白金黒メッキと同じ、ヘキサクロロ白金（ＩＶ）酸（Ｈ2［ＰｔＣｌ6］）の水溶液（通常、３ｇを１００ｍｌの水に溶かしたもの。）に酢酸鉛（通常、０．０２〜０．０３ｇ。）を加えたの溶液を用いることができる。 As a plating solution, lead acetate (usually 0) is used in an aqueous solution of hexachloroplatinic (IV) acid (H 2 [PtCl 6 ]), which is the same as conventional platinum black plating (usually 3 g dissolved in 100 ml of water). 0.02 to 0.03 g.) Can be used.

電流条件としては、直流電流を用いる場合、極に白金メッキが成される方向の電流（以下「順方向電流」という。）の単位時間当たりの電流密度が０．３ｍＡ／ｃｍ2・ｓ以下となる直流電流を用いることが好ましい。一方、順方向電流の単位時間当たりの電流密度は、０．０５ｍＡ／ｃｍ2・ｓ以上とするのが好ましい。従って、メッキ電流として直流を用いる場合には、順方向電流の単位時間当たりの電流密度は、０．０５〜０．３ｍＡ／ｃｍ2・ｓとすることが好ましい。 As a current condition, when a direct current is used, a current density per unit time of a current in a direction in which platinum plating is performed on a pole (hereinafter referred to as “forward current”) is 0.3 mA / cm 2 · s or less. It is preferable to use a direct current. On the other hand, the current density per unit time of the forward current is preferably 0.05 mA / cm 2 · s or more. Therefore, when DC is used as the plating current, the current density per unit time of the forward current is preferably 0.05 to 0.3 mA / cm 2 · s.

又、上述のような単位時間当たりの電流密度の順方向電流を流すと共に、所定期間、順方向電流とは逆極性の電流（以下「逆電流」という。）を流すことができる。斯かる逆電流は、順方向電流を所定期間流した後に所定期間流してもよいし、順方向電流と交互にそれぞれ所定期間、複数回ずつ流してもよい。つまり、順方向電流を（１）、逆電流を（２）として、（１）＋（２）、（１）＋（２）＋（１）、或いは（１）＋（２）の繰り返しなどとすることができる。   In addition, a forward current having a current density per unit time as described above can flow, and a current having a polarity opposite to the forward current (hereinafter referred to as “reverse current”) can flow for a predetermined period. Such a reverse current may flow for a predetermined period after flowing the forward current for a predetermined period, or may flow for a predetermined period alternately for a predetermined period, alternately with the forward current. That is, assuming that the forward current is (1) and the reverse current is (2), (1) + (2), (1) + (2) + (1), or (1) + (2) is repeated can do.

尚、上述のように逆電流を流す時の電流値は、順方向電流の値の約１０倍程度としてもよく、斯かる電流によって白金メッキ層Ｐが剥離することはない。逆電流を流すことにより、極に付着、吸蔵したヘキサクロロ白金（ＩＶ）酸及び塩素を除くことができ（電解洗浄）、効率的にメッキを行うことができる。   Note that the current value when the reverse current is passed as described above may be about 10 times the value of the forward current, and the platinum plating layer P is not peeled off by such a current. By flowing a reverse current, hexachloroplatinic (IV) acid and chlorine adhering to and occluding from the pole can be removed (electrolytic cleaning), and plating can be performed efficiently.

更に、交流電流をも用いてもよい。交流を用いる場合、順方向電流の単位時間当たりの電流密度は６ｍＡ／ｃｍ2・ｓ以下とすることができる。一方、順方向電流の単位時間当たりの電流密度は、０．３ｍＡ／ｃｍ2・ｓ以上とする。従って、メッキ電流として交流を用いる場合には、順方向電流の単位時間当たりの電流密度は、０．３〜６ｍＡ／ｃｍ2・ｓとすることが好ましい。交流波形は特に限定されず、正弦波、矩形波などを適宜用いることができる。又、交流周波数も適宜選定することができるが、典型的には、直流から商用周波数（５０／６０Ｈｚ）までを好適に用いることができる。 Further, an alternating current may be used. When alternating current is used, the current density per unit time of the forward current can be 6 mA / cm 2 · s or less. On the other hand, the current density per unit time of the forward current is set to 0.3 mA / cm 2 · s or more. Therefore, when alternating current is used as the plating current, the current density per unit time of the forward current is preferably 0.3 to 6 mA / cm 2 · s. The AC waveform is not particularly limited, and a sine wave, a rectangular wave, or the like can be used as appropriate. Moreover, although an alternating frequency can also be selected suitably, typically, DC to a commercial frequency (50/60 Hz) can be used conveniently.

上述のようにして隔膜型センサ１０Ａの作用極１４に灰色を呈する白金メッキ層Ｐを設けることによって、極表面の活性を維持すると共に、該白金メッキ層Ｐを、取れ難く、物理的強度をも備えたものとし、感度低下を抑制することができる。   As described above, by providing the working electrode 14 of the diaphragm type sensor 10A with the gray platinum plating layer P, the activity of the electrode surface is maintained, and the platinum plating layer P is difficult to remove and has a physical strength. It is possible to suppress the decrease in sensitivity.

本発明の隔膜型センサの感度復帰方法は、この灰色を呈する白金メッキ層Ｐが施された極を有する隔膜型センサに適用することができる。これにより、隔膜型センサの感度劣化自体が低減されると共に、感度が劣化した際にも極めて容易に感度を回復することができる。これにより、更に隔膜型センサのメンテナンス容易となる。   The method for returning the sensitivity of the diaphragm type sensor of the present invention can be applied to a diaphragm type sensor having a pole on which the platinum plating layer P exhibiting gray is applied. Thereby, the sensitivity degradation of the diaphragm type sensor itself is reduced, and the sensitivity can be recovered very easily even when the sensitivity is degraded. This further facilitates maintenance of the diaphragm type sensor.

上述のように、灰色を呈する白金メッキは、物理的な強度を備えているなど、上述のような利点を有するものであり、本発明を適用する隔膜型センサが備える白金メッキとして好ましく採用し得るものであるが、本発明は、隔膜型センサが備える白金メッキの状態を何ら限定するものではない。   As described above, the platinum plating exhibiting gray has the above-mentioned advantages such as having physical strength, and can be preferably employed as the platinum plating provided in the diaphragm type sensor to which the present invention is applied. However, the present invention does not limit the platinum plating state of the diaphragm type sensor.

実施例３
本実施例では、本発明の効果を確認するために、隔膜型センサ１０Ａ（溶存水素センサ）、計測器２０を下記のように作製して、感度復帰動作を実施した。尚、ここでは、実施例２にて説明した灰色を呈する白金メッキを作用極１４の表面に施されている隔膜型センサ１０Ａを用いた。 Example 3
In this example, in order to confirm the effect of the present invention, the diaphragm type sensor 10A (dissolved hydrogen sensor) and the measuring instrument 20 were produced as follows, and the sensitivity return operation was performed. Here, the diaphragm type sensor 10 </ b> A in which the gray platinum plating described in the second embodiment is applied to the surface of the working electrode 14 was used.

［隔膜型センサ：東亜ディーケーケー（株）製 ＥＬＤ００２Ｖ］
・作用極：Ｐｔ、φ２ｍｍ
・対極Ａｇ／ＡｇＣｌ
・メッキ層：灰色を呈する白金メッキ層
（メッキ条件：０．５ｍＡ×１．５分
−１０ｍＡ×１分
０．５ｍＡ×１．５分）
・メッキ液
（ヘキサクロロ白金（ＩＶ）酸３ｇを１００ｍｌの水に溶かし、
酢酸鉛を０．０３ｇ加えたもの）
［計測器：東亜ディーケーケー（株）製 ＤＨＤＩ−１（Ｓ）］
・測定電圧：５００ｍＶ
・測定電流：５〜７０μＡ
・感度復帰電圧：＋１Ｖ（又は−１Ｖ）、５ｓ
・感度復帰電流：７００〜３５００μＡ（測定電流の最大値の１０〜５０倍） [Diaphragm type sensor: ELD002V manufactured by TOA DK Corporation]
・ Working electrode: Pt, φ2mm
・ Counter electrode Ag / AgCl
・ Plating layer: Platinum plating layer showing gray (Plating condition: 0.5 mA × 1.5 minutes)
-10mA x 1 minute
0.5mA x 1.5 minutes)
・ Plating solution (3 g of hexachloroplatinum (IV) acid dissolved in 100 ml of water,
0.03g of lead acetate added)
[Instrument: DHDI-1 (S) manufactured by Toa DK Corporation]
・ Measurement voltage: 500mV
・ Measurement current: 5 to 70 μA
Sensitivity return voltage: + 1V (or -1V), 5s
Sensitivity return current: 700 to 3500 μA (10 to 50 times the maximum value of measurement current)

結果を図１１に示す。図中横軸は経過時間（日数）を示し、縦軸は、試験開始時（経過日数０日）の出力に対する経過日数毎の出力相対値（％）を示す。尚、被検液は、濃度１００％の純水素であった。   The results are shown in FIG. In the figure, the horizontal axis indicates the elapsed time (days), and the vertical axis indicates the output relative value (%) for each elapsed day with respect to the output at the start of the test (elapsed days 0 days). The test solution was pure hydrogen having a concentration of 100%.

図１１に示すように、試験開始かあ時間が経過すると、徐々に出力（感度）が劣化してくる。そして、本発明に従って感度復帰操作を行うことによって、感度は速やかに復帰した。又、図１１に示すように、感度復帰電流として酸化電流（正極性）、還元電流（負極性）のいずれの電流を用いても、感度復帰効果を得ることができた。   As shown in FIG. 11, the output (sensitivity) gradually deteriorates after the test has started. The sensitivity was quickly restored by performing the sensitivity restoration operation according to the present invention. Further, as shown in FIG. 11, the sensitivity recovery effect could be obtained by using any of the oxidation current (positive polarity) and the reduction current (negative polarity) as the sensitivity recovery current.

尚、隔膜型センサ（溶存水素センサ）１０Ａとして、常法により白金黒メッキが作用極１４の表面に施されたものを用いて同様の実験を行った。その結果、図１１に示す結果と同様に、試験開始から時間が経過すると、徐々に出力（感度）が劣化してくるが、本発明に従って感度復帰操作を行うことによって、感度を復帰させ得ることが分かった。又、感度復帰電流として酸化電流（正極性）、還元電流（負極性）のいずれの電流を用いても、感度復帰効果を得ることができた。   A similar experiment was conducted using a diaphragm type sensor (dissolved hydrogen sensor) 10A having platinum black plating applied to the surface of the working electrode 14 by a conventional method. As a result, similar to the results shown in FIG. 11, the output (sensitivity) gradually deteriorates as time passes from the start of the test, but the sensitivity can be restored by performing the sensitivity restoration operation according to the present invention. I understood. Further, the sensitivity recovery effect could be obtained by using any of the oxidation current (positive polarity) and the reduction current (negative polarity) as the sensitivity recovery current.

実施例４
次に、本発明の他の実施例について説明する。尚、上記実施例の計測装置１００と実質的に同一又は相当する構成、機能を有する要素には同一符号を付し、詳しい説明は省略する。 Example 4
Next, another embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the element which has the structure and function substantially equivalent or equivalent to the measuring apparatus 100 of the said Example, and detailed description is abbreviate | omitted.

上記各実施例では、隔膜型センサ１０Ａの隔膜１３をセンサ本体１１から取り外すことなく感度復帰操作を行う場合について説明した。しかし、本発明はこれに限定されるものではない。本発明の感度復帰方法は、隔膜型センサの隔膜を取り外してから実施することもできる。   In each of the above-described embodiments, the case where the sensitivity return operation is performed without removing the diaphragm 13 of the diaphragm sensor 10A from the sensor body 11 has been described. However, the present invention is not limited to this. The sensitivity recovery method of the present invention can also be carried out after removing the diaphragm of the diaphragm type sensor.

隔膜型センサ１０Ａのセンサ本体１１から隔膜１３を取り外して感度復帰を行う場合には、作用極４と、別途用意した感度復帰用の外部補助電極との間に電圧を印加することができる。この場合、導電媒体としては、隔膜型センサ１０Ａと共に使用することが許容される任意の電解液を用いることができる。斯かる導電媒体は、室１１ａ内に収容される電解液１７と同種であっても異種であってもよい。例えば、０．１ｍｏｌ／Ｌ ＫＣｌ＋０．１ｍｏｌ／Ｌ ＫＯＨを好適に用いることができる。   When the diaphragm 13 is removed from the sensor body 11 of the diaphragm type sensor 10A and the sensitivity is restored, a voltage can be applied between the working electrode 4 and a separately prepared external auxiliary electrode for sensitivity restoration. In this case, as the conductive medium, any electrolytic solution that can be used with the diaphragm type sensor 10A can be used. Such a conductive medium may be the same as or different from the electrolyte solution 17 accommodated in the chamber 11a. For example, 0.1 mol / L KCl + 0.1 mol / L KOH can be preferably used.

図４は、隔膜型センサ１０Ａの隔膜１３を取り外して感度復帰操作を行い得る計測装置１００の概略機能ブロックを示す。この場合、ビーカー等の適用な容器４０中に導電媒体４２を入れ、隔膜１３を取り外した隔膜型センサ１０Ａの少なくとも作用極１４と、感度復帰用に別途用意された外部補助電極１９とを、容器４０内の導電媒体４２に浸漬する。外部補助電極１９は、リード線１９ａを介して計測器２０の電源回路２１に接続される。   FIG. 4 shows a schematic functional block of the measuring apparatus 100 that can perform sensitivity return operation by removing the diaphragm 13 of the diaphragm type sensor 10A. In this case, at least the working electrode 14 of the diaphragm type sensor 10A in which the conductive medium 42 is put in an applicable container 40 such as a beaker and the diaphragm 13 is removed, and the external auxiliary electrode 19 separately prepared for sensitivity recovery are provided in the container. It is immersed in a conductive medium 42 in 40. The external auxiliary electrode 19 is connected to the power circuit 21 of the measuring instrument 20 through the lead wire 19a.

電源回路２１は、測定用電源２１ａと、感度復帰用電源２１ｂと、切替器２１ｃとを有する。測定時には、切替器２１ｃは、隔膜型センサ１０Ａの作用極１４と対極１５とを測定用電源２１ａに接続する。そして、図３に示す態様と概略同様にして、感度復帰操作時には、操作者による操作部２３からの指示に応じて、切替器２１ｃは作用極１４と外部補助電極１９とを感度復帰用電源２１ｂに接続する。そして、作用極１４と外部補助電極１９との間に感度復帰電圧を印加し、作用極１４に感度復帰電流を流す。   The power supply circuit 21 includes a measurement power supply 21a, a sensitivity recovery power supply 21b, and a switch 21c. At the time of measurement, the switch 21c connects the working electrode 14 and the counter electrode 15 of the diaphragm type sensor 10A to the measurement power source 21a. In the same manner as in the mode shown in FIG. 3, when the sensitivity return operation is performed, the switch 21 c connects the working electrode 14 and the external auxiliary electrode 19 to the sensitivity return power source 21 b according to an instruction from the operation unit 23 by the operator. Connect to. Then, a sensitivity return voltage is applied between the working electrode 14 and the external auxiliary electrode 19, and a sensitivity return current flows through the working electrode 14.

尚、別法では、隔膜型センサ１０Ａのセンサ本体１１から隔膜１３を取り外して感度復帰操作を行う場合にも、作用極４と、対極５又は上述の内部補助電極１８（図３）との間に感度復帰電圧を印加して、作用極１４に感度復帰電流を流すようにしてもよい。この場合、計測装置１００の機能ブロックは、図２又は図３に示すものと同様であってよい。そして、この場合には、単に、感度復帰操作時に、図４に示すようにして、隔膜１３を取り外した隔膜型センサ１０Ａの少なくとも作用極１４と、対極１５又は内部補助電極１８とを、ビーカー等の適用な容器４０内の導電媒体４２に浸漬するようにすればよい。   In another method, even when the diaphragm 13 is removed from the sensor body 11 of the diaphragm type sensor 10A and the sensitivity return operation is performed, the gap between the working electrode 4 and the counter electrode 5 or the above-described internal auxiliary electrode 18 (FIG. 3). A sensitivity recovery voltage may be applied to the working electrode 14 to apply a sensitivity recovery voltage. In this case, the functional block of the measuring apparatus 100 may be the same as that shown in FIG. In this case, at the time of sensitivity return operation, as shown in FIG. 4, at least the working electrode 14 and the counter electrode 15 or the internal auxiliary electrode 18 of the diaphragm type sensor 10A from which the diaphragm 13 is removed are connected to a beaker or the like. What is necessary is just to immerse in the electrically conductive medium 42 in the container 40 to which this is applied.

以上、隔膜型センサ１０Ａの隔膜１３を取り外して本発明の隔膜型センサの感度復帰方法を実施する場合について説明した。この場合、従来の作用極４に従来の白金黒メッキが施されている場合には、白金黒メッキの剥離に注意を払わなければならない。一方、作用極４に、先に本出願人が提案した灰色を呈する白金メッキが施されている場合には、白金メッキは機械的強度に優れているので操作は容易である。   The case where the diaphragm 13 of the diaphragm sensor 10A is removed and the sensitivity return method for the diaphragm sensor of the present invention is performed has been described above. In this case, when conventional platinum black plating is applied to the conventional working electrode 4, attention must be paid to peeling of the platinum black plating. On the other hand, when the working electrode 4 is subjected to the platinum plating which has been proposed by the present applicant and has a gray color, the platinum plating is excellent in mechanical strength, so that the operation is easy.

実施例５
次に、本発明の更に他の実施例について説明する。尚、上記実施例の計測装置１００と実質的に同一又は相当する構成、機能を有する要素には同一符号を付し、詳しい説明は省略する。 Example 5
Next, still another embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the element which has the structure and function substantially equivalent or equivalent to the measuring apparatus 100 of the said Example, and detailed description is abbreviate | omitted.

上記実施例では、操作者が、隔膜型センサ１０Ａの感度が劣化したことを認知した際、或いは定期的に感度復帰操作を実施するとして説明した。しかし、本発明はこれに限定されるものではなく、計測器２０が自動的に感度復帰操作を実施するようにすることができる。   In the said Example, when the operator recognized that the sensitivity of 10 A of diaphragm type sensors deteriorated, it demonstrated as a sensitivity return operation being implemented regularly. However, the present invention is not limited to this, and the measuring instrument 20 can automatically perform the sensitivity return operation.

例えば、予め設定された所定タイミングで、計測器２０が自動的に感度復帰操作を行うようにすることができる。図５は、自動的に感度復帰操作を実施し得る計測装置１００の概略機能ブロックを示す。本実施例の計測装置１００は、概略、実施例１のものと同様であるが、本実施例では、制御部２５が電源回路２１を制御することによって、自動的に感度復帰動作を実施する。   For example, the measuring instrument 20 can automatically perform a sensitivity return operation at a predetermined timing set in advance. FIG. 5 shows schematic functional blocks of the measuring apparatus 100 that can automatically perform the sensitivity return operation. The measuring apparatus 100 of the present embodiment is generally the same as that of the first embodiment, but in this embodiment, the control unit 25 controls the power supply circuit 21 to automatically perform the sensitivity recovery operation.

制御部２５は、制御の中心的素子であるＣＰＵ（制御手段）２５ａと、記憶手段としてのＲＯＭ２５ｂ、ＲＡＭ２５ｃ等を有する。そして、ＣＰＵ２５ａは、ＲＯＭ２５ｂ、ＲＡＭ２５ｃに記憶されたプログラム、データに従って、計測器２０の動作を統括制御する。又、制御部２５には、操作部２３が接続されており、操作部２３が備える入力手段（キー入力部等）からの各種設定、測定の開始／停止等を制御部２５に入力して指示することができる。   The control unit 25 includes a CPU (control unit) 25a that is a central element of control, a ROM 25b, a RAM 25c, and the like as storage units. Then, the CPU 25a performs overall control of the operation of the measuring instrument 20 according to programs and data stored in the ROM 25b and RAM 25c. An operation unit 23 is connected to the control unit 25, and various settings from the input means (key input unit etc.) provided in the operation unit 23, start / stop of measurement, etc. are input to the control unit 25 and instructed. can do.

本実施例では、予め操作者は、感度復帰操作を実施するタイミングを、操作部２３から設定する。即ち、制御部２５のＣＰＵ２５ａは、操作部２３から入力された感度復帰操作の実施タイミングに関する情報を、ＲＡＭ（本実施例では不揮発性メモリ）２５ｃに記憶させる。ＣＰＵ２５ａは、例えば連続測定時には、測定動作を制御すると共に定期的に、感度復帰操作を実施する所定のタイミングとなったかを監視する。そして、感度復帰操作を実施するタイミングになると、電源回路２１を制御して、作用極１４と対極１５との間に感度復帰電圧を印加させて、作用極１４に感度復帰電流を流す。   In the present embodiment, the operator sets the timing for performing the sensitivity return operation from the operation unit 23 in advance. That is, the CPU 25a of the control unit 25 stores information on the execution timing of the sensitivity return operation input from the operation unit 23 in the RAM (nonvolatile memory in this embodiment) 25c. For example, during continuous measurement, the CPU 25a controls the measurement operation and periodically monitors whether a predetermined timing for executing the sensitivity return operation has come. Then, when it is time to perform the sensitivity return operation, the power supply circuit 21 is controlled to apply a sensitivity return voltage between the working electrode 14 and the counter electrode 15, and a sensitivity return current flows through the working electrode 14.

即ち、測定時には、ＣＰＵ２５ａの制御によって、電源回路２１は、切替器２１ｃによって作用極１４と対極１５とを測定用電源２１ａに接続し、そして測定用電源２１ａから測定用電圧を作用極１４と対極１５との間に印加する。そして、ＣＰＵ２５ａによって感度復復帰操作の実施が指示されると、電源回路２１は、測定用電源２１ａからの電圧印加を停止すると共に、切替器２１ｃによって作用極１４と対極１５とを感度復帰用電源２１ｂに接続する。そして、作用極１４と対極１５との間に感度復帰電圧を印加し、作用極１４に感度復帰電流を流す。又、ＣＰＵ２５ａの指示により、所定時間感度復帰操作を行った後に、電源回路２１の状態を通常の測定状態に戻る。   That is, at the time of measurement, the power supply circuit 21 connects the working electrode 14 and the counter electrode 15 to the measuring power supply 21a by the switch 21c and controls the measuring voltage from the measuring power supply 21a to the working electrode 14 and the counter electrode under the control of the CPU 25a. 15 is applied. When the CPU 25a instructs the execution of the sensitivity recovery operation, the power supply circuit 21 stops the voltage application from the measurement power supply 21a, and the switch 21c connects the working electrode 14 and the counter electrode 15 to the sensitivity recovery power supply. Connect to 21b. Then, a sensitivity return voltage is applied between the working electrode 14 and the counter electrode 15, and a sensitivity return current flows through the working electrode 14. Further, after the sensitivity return operation is performed for a predetermined time in accordance with an instruction from the CPU 25a, the state of the power supply circuit 21 is returned to the normal measurement state.

ところで、隔膜型センサ１０Ａの感度劣化がどの程度の期間で起こるかは、使用者が通常経験的に予測できるものであるか、或いは製造元が適当な期間を指示する。従って、上述のように予め操作者が感度復帰操作を実施する所定タイミングを入力により設定することが可能である他、製造時或いは工場出荷時に、計測器２０が感度復帰操作を実施する所定タイミング（１種類であっても複数種類であってもよい。）に関する情報を、ＲＯＭ２５ｂやＲＡＭ２５ｃに予め保持させることができる。通常、測定精度等との関係で、感度劣化が許容し得るものでなくなる前に、感度復帰操作を実施するのが好ましい。本発明は、どのような期間毎に感度復帰操作を行うべきかについて、何ら限定するものではない。   By the way, how long the sensitivity degradation of the diaphragm type sensor 10A occurs can be normally predicted by the user empirically, or the manufacturer indicates an appropriate period. Therefore, as described above, the operator can set in advance the predetermined timing for performing the sensitivity return operation by inputting, and also the predetermined timing (when the measuring instrument 20 performs the sensitivity return operation at the time of manufacture or factory shipment). Information regarding one type or a plurality of types may be stored in the ROM 25b or the RAM 25c in advance. Usually, it is preferable to perform the sensitivity recovery operation before sensitivity deterioration becomes unacceptable in relation to measurement accuracy and the like. The present invention does not limit what period the sensitivity return operation should be performed.

尚、図３を参照して実施例１にて説明した、センサ本体１１内に内部補助電極１８を有する態様においても、上記同様の制御部２５を設けることで自動化が可能であることは以上の説明から明らかである。   In the aspect having the internal auxiliary electrode 18 in the sensor body 11 described in the first embodiment with reference to FIG. 3, it is possible to automate by providing the same control unit 25 as described above. It is clear from the explanation.

以上、本実施例によれば、隔膜型センサの感度復帰方法は、隔膜１３を取り外すことなく感度復帰操作を実施することができるので、典型的には、通常の測定状態にある隔膜型センサ１０Ａに関し、上述のように予め設定された所定タイミングで感度復帰操作を自動的に実施することができる。これにより、感度劣化を飛躍的に低減することができ、隔膜型センサ１０Ａを連続測定等において長期にわたり使用することができる。特に、極が備える白金メッキ層Ｐが実施例２にて説明した灰色を呈する白金メッキである場合、感度劣化自体が非常に小さいため、適当な期間毎に自動的に感度復帰操作を行うことで、実質的に感度劣化が起こらないか、極小とすることができる。   As described above, according to the present embodiment, the sensitivity return method of the diaphragm type sensor can perform the sensitivity return operation without removing the diaphragm 13, and therefore, typically, the diaphragm type sensor 10A in the normal measurement state. As described above, the sensitivity recovery operation can be automatically performed at a predetermined timing set in advance as described above. Thereby, sensitivity deterioration can be reduced drastically, and the diaphragm type sensor 10A can be used for a long period of time in continuous measurement or the like. In particular, when the platinum plating layer P included in the pole is the platinum plating exhibiting the gray color described in the second embodiment, the sensitivity deterioration itself is very small. Therefore, the sensitivity recovery operation is automatically performed every appropriate period. The sensitivity is not substantially deteriorated or can be minimized.

実施例６
次に、本発明の他の実施例について説明する。 Example 6
Next, another embodiment of the present invention will be described.

上記各実施例では、隔膜型センサは、隔膜型ポーラログラフ式センサであるとして説明したが、本発明はこれに限定されるものではない。隔膜型センサとしては、図６に示すようなガルバニ電池式センサがある。本発明は、ガルバニ電池式センサとされる隔膜型センサにも同様に適用し得るものである。   In each of the above embodiments, the diaphragm type sensor is described as a diaphragm type polarographic sensor, but the present invention is not limited to this. As the diaphragm type sensor, there is a galvanic cell type sensor as shown in FIG. The present invention can be similarly applied to a diaphragm type sensor which is a galvanic cell type sensor.

図６に示すようなガルバニ電池式センサは、電源を有さず、使用時に外部から電圧を印加しないことが図１に示すようなポーラログラフ式センサとは異なる。即ち、図６に示す計測装置２００の計測器２０は、測定時に作用極１４と対極１５との間に電圧を印加する測定用電源を有していない。測定時には、作用極１４と対極１５とを電解液１７中にそれぞれ浸漬して回路を構成することにより、電極間に流れる電流を測定する。   A galvanic cell type sensor as shown in FIG. 6 does not have a power source and does not apply a voltage from the outside during use, unlike a polarographic sensor as shown in FIG. That is, the measuring instrument 20 of the measuring apparatus 200 shown in FIG. 6 does not have a measurement power source that applies a voltage between the working electrode 14 and the counter electrode 15 during measurement. At the time of measurement, the working electrode 14 and the counter electrode 15 are immersed in the electrolyte solution 17 to form a circuit, thereby measuring the current flowing between the electrodes.

従って、隔膜型ガルバニ電池式センサを備える計測装置２００は、図２〜５に示す機能ブロックにおける電源回路２１から、測定用電源２１ａを除いたものに相当する。即ち、切替器２１ｃは、感度復帰操作時に作用極１４と対極（或いは内部補助電極１８、１９）との間に感度復帰用電源２１ｂを接続し、感度復帰電圧を印加することで、作用極１４に感度復帰電流を流すように構成すればよい。   Therefore, the measuring apparatus 200 including the diaphragm type galvanic cell type sensor corresponds to the power supply circuit 21 in the functional block shown in FIGS. 2 to 5 excluding the measurement power supply 21a. That is, the switch 21c connects the sensitivity return power source 21b between the working electrode 14 and the counter electrode (or the internal auxiliary electrodes 18 and 19) during the sensitivity return operation, and applies the sensitivity return voltage to thereby apply the sensitivity return voltage 14b. It is sufficient to configure so that a sensitivity return current flows through the.

以上、ガルバニ電池式の隔膜型センサの作用極に白金メッキ層Ｐが設けられている場合にも、容易に隔膜型センサ１０Ａの感度を復帰させることができる。又、作用極１４との間で電圧を印加するために、対極１５或いは室１１ａ内に設けられた内部補助電極１８を用い、導電媒体として室１１ａ内の電解液１７を用いることで、隔膜１３を取り外すことなく、その感度を、極めて容易に復帰させることができる。そして、隔膜型センサ１０の感度復帰のために隔膜１３の交換、再メッキの必要がないので、交換用隔膜、メッキ液の使用を飛躍的に低減することができる。   As described above, also when the platinum plating layer P is provided on the working electrode of the galvanic cell type diaphragm type sensor, the sensitivity of the diaphragm type sensor 10A can be easily restored. In order to apply a voltage between the working electrode 14 and the counter electrode 15 or the internal auxiliary electrode 18 provided in the chamber 11a, and using the electrolytic solution 17 in the chamber 11a as a conductive medium, the diaphragm 13 is used. The sensitivity can be restored very easily without removing the. In addition, since it is not necessary to replace and replate the diaphragm 13 in order to restore the sensitivity of the diaphragm sensor 10, it is possible to dramatically reduce the use of the replacement diaphragm and the plating solution.

以上、本発明を幾つかの実施例に則して説明したが本発明は上記各実施例の態様に限定されるものではないことを理解されたい。   As mentioned above, although this invention was demonstrated according to some Examples, it should be understood that this invention is not limited to the aspect of each said Example.

例えば、上記各実施例においては、計測器２０が感度復帰用電源２１ｂ等を有し、感度復帰操作を実施するものとして説明したが、本発明はこの態様に限定されるものではなく、上記同様の感度復帰操作に供し得る別個の電極再生装置（図示せず）を使用してもよい。つまり、電極再生装置は、隔膜型センサ１０を接続することによって、作用極１４に感度復帰電流を流すことができるように、上記感度復帰用電源２１ｃに相当する電源回路を有する構成とする。そして、この電極再生装置に隔膜型センサ１０Ａを接続することによって、作用極１４と対極１５（或いは室１１ａ内に設けられた内部補助電極１８）がこの電源回路に接続されるようにする。或いは、隔膜型センサ１０を接続することによって作用極１４がその電源回路に接続され、又、別途用意した外部補助電極１９を電極再生装置に接続することで、外部補助電極１９が電源回路に接続されるようにする。これにより、上記各実施例と同様にして、作用極１４に感度復帰電流を流すことができる。   For example, in each of the above-described embodiments, the measuring instrument 20 has the power supply 21b for returning the sensitivity and the like, and the sensitivity returning operation is performed. However, the present invention is not limited to this aspect, and the same as above. A separate electrode regenerator (not shown) that can be used for the sensitivity recovery operation may be used. In other words, the electrode regeneration device has a power supply circuit corresponding to the sensitivity restoration power source 21c so that the sensitivity restoration current can flow through the working electrode 14 by connecting the diaphragm type sensor 10. Then, the diaphragm type sensor 10A is connected to this electrode regenerating device so that the working electrode 14 and the counter electrode 15 (or the internal auxiliary electrode 18 provided in the chamber 11a) are connected to this power supply circuit. Alternatively, the working electrode 14 is connected to the power supply circuit by connecting the diaphragm type sensor 10, and the external auxiliary electrode 19 is connected to the power supply circuit by connecting the external auxiliary electrode 19 prepared separately to the electrode regeneration device. To be. Thereby, the sensitivity return current can be supplied to the working electrode 14 in the same manner as in the above embodiments.

このように、計測器２０とは別の電極再生装置によって感度復帰操作を行う場合、感度復帰操作のために隔膜型センサ１０Ａは計測器２０から取り外して、電極再生装置に接続しなければならないが、従来の最メッキによる感度復帰操作と比較して飛躍的に操作性は向上していることに変わりない。又、測定操作とは独立して隔膜型センサ１０Ａの感度復帰操作を実施することができるので、例えば複数の隔膜型センサ１０Ａを交換使用する場合などには好都合である。   As described above, when the sensitivity restoration operation is performed by an electrode regeneration device different from the measuring instrument 20, the diaphragm type sensor 10A must be removed from the measuring instrument 20 and connected to the electrode regeneration device for the sensitivity restoration operation. As compared with the sensitivity return operation by the conventional top plating, the operability is still greatly improved. Further, since the sensitivity return operation of the diaphragm type sensor 10A can be performed independently of the measurement operation, it is convenient when, for example, a plurality of diaphragm type sensors 10A are used for replacement.

又、上記各実施例では、極表面に白金メッキが施されている場合の感度復帰について説明したが、極自体が白金族触媒で作製されているか、極表面に白金族触媒層が設けられている場合にも、同様にして感度復帰を行うことができる。   In each of the above embodiments, the sensitivity recovery when the platinum surface is plated with platinum has been described. However, the electrode itself is made of a platinum group catalyst or a platinum group catalyst layer is provided on the pole surface. In the case where there is, sensitivity recovery can be performed in the same manner.

本発明を適用し得る隔膜型センサ（隔膜型ポーラログラフ式センサ）の一例の要部概略断面図である。It is a principal part schematic sectional drawing of an example of the diaphragm type sensor (diaphragm type polarographic sensor) which can apply this invention. 本発明に従う感度復帰操作の一実施例の概略制御態様を示すブロック図である。It is a block diagram which shows the general | schematic control aspect of one Example of the sensitivity reset operation according to this invention. 本発明に従う感度復帰操作の他の実施例の概略制御態様を示すブロック図である。It is a block diagram which shows the general | schematic control aspect of the other Example of the sensitivity return operation according to this invention. 本発明に従う感度復帰操作の他の実施例の概略制御態様を示すブロック図である。It is a block diagram which shows the general | schematic control aspect of the other Example of the sensitivity return operation according to this invention. 本発明に従う感度復帰操作の他の実施例の概略制御態様を示すブロック図である。It is a block diagram which shows the general | schematic control aspect of the other Example of the sensitivity return operation according to this invention. 本発明を適用し得る隔膜型センサ（隔膜型ガルバニ電池式センサ）の一例の要部概略断面図である。It is a principal part schematic sectional drawing of an example of the diaphragm type sensor (diaphragm type | mold galvanic cell type sensor) which can apply this invention. 白金メッキ層の形成方法を説明するための模式図である。It is a schematic diagram for demonstrating the formation method of a platinum plating layer. 灰色を呈する白金メッキ層の形成方法の原理を説明するための概念図である。It is a conceptual diagram for demonstrating the principle of the formation method of the platinum plating layer which exhibits gray. メッキ条件により変化する白金メッキ層表面の走査型電子顕微鏡（ＳＥＭ）画像を示す説明図である。It is explanatory drawing which shows the scanning electron microscope (SEM) image of the platinum plating layer surface which changes with plating conditions. メッキ条件により変化する白金メッキ層表面の走査型電子顕微鏡（ＳＥＭ）画像を示す説明図である。It is explanatory drawing which shows the scanning electron microscope (SEM) image of the platinum plating layer surface which changes with plating conditions. 本発明の効果を示すグラフ図である。It is a graph which shows the effect of this invention.

符号の説明Explanation of symbols

１０ 隔膜型センサ
１３ 隔膜
１４ 作用極（電極）
１５ 対極
１８ 内部補助電極
１９ 外部補助電極
２０ 計測器
２１ 電源回路（電流発生器、電圧印加手段）
２１ａ 測定用電源（第１の電圧印加手段）
２１ｂ 感度復帰用電源（第２の電圧印加手段）
２２ 電流計
１００ 計測装置 10 Diaphragm sensor 13 Diaphragm 14 Working electrode (electrode)
15 Counter electrode 18 Internal auxiliary electrode 19 External auxiliary electrode 20 Measuring instrument 21 Power supply circuit (current generator, voltage application means)
21a Measurement power supply (first voltage applying means)
21b Power supply for returning sensitivity (second voltage applying means)
22 Ammeter 100 Measuring device

Claims (22)

センサ本体の一端に試料中の測定対象成分を透過させる隔膜が着脱自在であり、前記隔膜によって外部と区画される室の内部に、表面に白金族触媒層又は白金メッキ層が設けられた作用極と、対極と、が配置され、前記作用極と前記対極とが前記室内に収容された電解液に接触した状態で、前記隔膜を透過した測定対象成分が前記作用極の表面で反応することにより前記作用極と対極との間に流れる測定電流を測定するための隔膜型センサの感度復帰方法において、
前記作用極に前記測定電流とは異なる感度復帰電流を流すことを特徴とする隔膜型センサの感度復帰方法。 A working electrode in which a diaphragm for allowing a measurement target component in a sample to pass through is detachable at one end of the sensor body, and a platinum group catalyst layer or a platinum plating layer is provided on the surface inside a chamber partitioned from the outside by the diaphragm. And the counter electrode, and in a state where the working electrode and the counter electrode are in contact with the electrolyte contained in the chamber, the measurement target component that has passed through the diaphragm reacts on the surface of the working electrode. In the sensitivity return method of the diaphragm type sensor for measuring the measurement current flowing between the working electrode and the counter electrode,
A sensitivity return method for a diaphragm type sensor, wherein a sensitivity return current different from the measurement current is passed through the working electrode. 前記感度復帰電流の量は、測定時に前記作用極に流れる前記測定電流の量の最大値よりも大きいことを特徴とする請求項１の隔膜型センサの感度復帰方法。   The method of claim 1, wherein the amount of the sensitivity return current is larger than a maximum value of the amount of the measurement current flowing through the working electrode during measurement. 前記感度復帰電流の量は、測定時に前記作用極に流れる前記測定電流の最大値の５倍以上であることを特徴とする請求項１又は２の隔膜型センサの感度復帰方法。   The method of claim 1 or 2, wherein the amount of the sensitivity return current is at least five times the maximum value of the measurement current flowing through the working electrode during measurement. 前記隔膜を前記センサ本体から取り外すことなく、前記作用極と、前記対極又は前記対極とは別個に前記室内に設けられた内部補助電極と、の間に電圧を印加することにより、前記室内に収容された前記電解液を導電媒体として前記作用極に前記感度復帰電流を流すことを特徴とする請求項１、２又は３の隔膜型センサの感度復帰方法。   Without removing the diaphragm from the sensor body, it is accommodated in the room by applying a voltage between the working electrode and the counter electrode or an internal auxiliary electrode provided in the room separately from the counter electrode. 4. The sensitivity return method of a diaphragm type sensor according to claim 1, wherein the sensitivity return current is caused to flow through the working electrode using the electrolyte solution as a conductive medium. 前記隔膜を前記センサ本体から取り外し、前記作用極と、前記対極、前記対極とは別個に前記室内に設けられた内部補助電極又は前記隔膜型センサとは別個の外部補助電極と、を導電媒体中に浸漬して、前記作用極と、前記対極、前記内部補助電極又は前記外部補助電極と、の間に電圧を印加することにより前記作用極に前記感度復帰電流を流すことを特徴とする請求項１、２又は３の隔膜型センサの感度復帰方法。   The diaphragm is removed from the sensor body, and the working electrode, the counter electrode, an internal auxiliary electrode provided in the chamber separately from the counter electrode, or an external auxiliary electrode separate from the diaphragm sensor in a conductive medium The sensitivity return current is caused to flow through the working electrode by applying a voltage between the working electrode and the counter electrode, the internal auxiliary electrode, or the external auxiliary electrode. Sensitivity return method for 1, 2 or 3 diaphragm type sensors. 前記作用極に、前記感度復帰電流として正極性又は負極性の直流電流を流すことを特徴とする請求項１〜５のいずれかの項に記載の隔膜型センサの感度復帰方法。   6. The sensitivity return method for a diaphragm type sensor according to claim 1, wherein a positive or negative direct current is passed through the working electrode as the sensitivity return current. 前記作用極に、前記感度復帰電流として正極性及び負極性の直流電流を交互に流すか、又は、交流電流を流すことを特徴とする請求項１〜５のいずれかの項に記載の隔膜型センサの感度復帰方法。   The diaphragm type according to any one of claims 1 to 5, wherein a positive current and a negative direct current are alternately supplied to the working electrode as the sensitivity return current, or an alternating current is supplied. Sensor sensitivity recovery method. 前記隔膜型センサは、ポーラログラフ式センサ又はガルバニ電池式センサであることを特徴とする請求項１〜７のいずれかの項に記載の隔膜型センサの感度復帰方法。   The method of claim 1, wherein the diaphragm type sensor is a polarographic sensor or a galvanic cell type sensor. 前記隔膜型センサは、水素ガスセンサ又は溶存水素センサであることを特徴とする請求項１〜８のいずれかの項に記載の隔膜型センサの感度復帰方法。   The method for returning the sensitivity of a diaphragm type sensor according to any one of claims 1 to 8, wherein the diaphragm type sensor is a hydrogen gas sensor or a dissolved hydrogen sensor. 前記白金メッキ層として、白金黒メッキの層又は灰色を呈する白金メッキ層を有することを特徴とする請求項１〜９のいずれかの項に記載の隔膜型センサ。   The diaphragm type sensor according to any one of claims 1 to 9, wherein the platinum plating layer includes a platinum black plating layer or a gray platinum plating layer. センサ本体の一端に試料中の測定対象成分を透過させる隔膜が着脱自在であり、前記隔膜によって外部と区画される室の内部に、表面に白金族触媒層又は白金メッキ層が設けられた作用極と、対極と、が配置され、前記作用極と前記対極とが前記室内に収容された電解液に接触した状態で、前記隔膜を透過した測定対象成分が前記作用極の表面で反応することにより前記作用極と対極との間に流れる測定電流を測定するための隔膜型センサが接続される計測装置において、
前記作用極に流れる前記測定電流を検出する電流計と、
前記作用極に前記測定電流とは異なる感度復帰電流を流す感度復帰電流発生器と、
を有することを特徴とする計測装置。 A working electrode in which a diaphragm for allowing a measurement target component in a sample to pass through is detachable at one end of the sensor body, and a platinum group catalyst layer or a platinum plating layer is provided on the surface inside a chamber partitioned from the outside by the diaphragm. And the counter electrode, and in a state where the working electrode and the counter electrode are in contact with the electrolyte contained in the chamber, the measurement target component that has passed through the diaphragm reacts on the surface of the working electrode. In a measuring device to which a diaphragm type sensor for measuring a measurement current flowing between the working electrode and the counter electrode is connected,
An ammeter for detecting the measurement current flowing through the working electrode;
A sensitivity return current generator for passing a sensitivity return current different from the measurement current to the working electrode;
A measuring apparatus comprising: 前記感度復帰電流の量は、測定時に前記作用極に流れる前記測定電流の量の最大値よりも大きいことを特徴とする請求項１１の計測装置。   12. The measuring apparatus according to claim 11, wherein the amount of the sensitivity return current is larger than a maximum value of the amount of the measurement current flowing through the working electrode during measurement. 前記感度復帰電流の量は、測定時に前記作用極に流れる前記測定電流の最大値の５倍以上であることを特徴とする請求項１１又は１２の計測装置。   The measuring device according to claim 11 or 12, wherein the amount of the sensitivity return current is at least five times the maximum value of the measurement current flowing through the working electrode during measurement. 前記感度復帰電流発生器は、前記作用極と、前記対極又は前記対極とは別個に前記室内に設けられた内部補助電極と、の間に電圧を印加することにより、前記室内に収容された前記電解液を導電媒体として前記作用極に前記感度復帰電流を流すことを特徴とする請求項１１、１２又は１３の計測装置。   The sensitivity return current generator is housed in the room by applying a voltage between the working electrode and the counter electrode or an internal auxiliary electrode provided in the room separately from the counter electrode. 14. The measuring device according to claim 11, wherein the sensitivity return current is caused to flow through the working electrode using an electrolytic solution as a conductive medium. 前記感度復帰電流発生器は、所定タイミングで自動的に前記作用極に感度復帰電流を流すことを特徴とする１４の計測装置。   14. The measuring device according to claim 14, wherein the sensitivity return current generator automatically sends a sensitivity return current to the working electrode at a predetermined timing. 前記感度復帰電流発生器は、前記作用極と、前記対極、前記対極とは別個に前記室内に設けられた内部補助電極又は前記隔膜型センサとは別個の外部補助電極と、の間に電圧を印加することにより、前記作用極と、前記対極、前記内部補助電極又は前記外部補助電極と、が浸漬された前記隔膜型センサ外の導電媒体を介して前記作用極に電流を流すことを特徴とする請求項１１、１２又は１３の計測装置。   The sensitivity return current generator generates a voltage between the working electrode and the counter electrode, an internal auxiliary electrode provided in the room separately from the counter electrode, or an external auxiliary electrode separate from the diaphragm type sensor. When applied, a current is caused to flow to the working electrode through a conductive medium outside the diaphragm sensor in which the working electrode and the counter electrode, the internal auxiliary electrode, or the external auxiliary electrode are immersed. The measuring device according to claim 11, 12 or 13. 前記作用極に、前記感度復帰電流として正極性又は負極性の直流電流を流すことを特徴とする請求項１１〜１６のいずれかの項に記載の隔膜型センサの感度復帰方法。   17. The method of returning sensitivity of a diaphragm type sensor according to claim 11, wherein a positive or negative direct current is passed as the sensitivity return current through the working electrode. 前記作用極に、前記感度復帰電流として正極性及び負極性の直流電流を交互に流すか、又は、交流電流を流すことを特徴とする請求項１１〜１６のいずれかの項に記載の隔膜型センサの感度復帰方法。   The diaphragm type according to any one of claims 11 to 16, wherein a positive current and a negative direct current are alternately supplied to the working electrode as the sensitivity return current, or an alternating current is supplied. Sensor sensitivity recovery method. 前記隔膜型センサは、ポーラログラフ式センサ又はガルバニ電池式センサであることを特徴とする請求項１１〜１８のいずれかの項に記載の隔膜型センサの感度復帰方法。   19. The method for returning the sensitivity of a diaphragm type sensor according to claim 11, wherein the diaphragm type sensor is a polarographic sensor or a galvanic cell sensor. 前記隔膜型センサは、水素ガスセンサ又は溶存水素センサであることを特徴とする請求項１１〜１９のいずれかの項に記載の隔膜型センサの感度復帰方法。   The method for returning the sensitivity of a diaphragm type sensor according to any one of claims 11 to 19, wherein the diaphragm type sensor is a hydrogen gas sensor or a dissolved hydrogen sensor. 前記白金メッキ層として、白金黒メッキの層又は灰色を呈する白金メッキ層を有することを特徴とする請求項１１〜２０のいずれかの項に記載の隔膜型センサ。   The diaphragm type sensor according to any one of claims 11 to 20, wherein the platinum plating layer includes a platinum black plating layer or a gray platinum plating layer. センサ本体の一端に試料中の測定対象成分を透過させる隔膜が着脱自在であり、前記隔膜によって外部と区画される室の内部に、表面に白金族触媒層又は白金メッキ層が設けられた作用極と、対極と、が配置され、前記作用極と前記対極とが前記室内に収容された電解液に接触した状態で、前記隔膜を透過した測定対象成分が前記作用極の表面で反応することにより前記作用極と対極との間に流れる測定電流を測定するための隔膜型センサが接続される電極再生装置において、
前記作用極に前記測定電流とは異なる感度復帰電流を流す感度復帰電流発生器を有することを特徴とする電極再生装置。 A working electrode in which a diaphragm for allowing a measurement target component in a sample to pass through is detachable at one end of the sensor body, and a platinum group catalyst layer or a platinum plating layer is provided on the surface inside a chamber partitioned from the outside by the diaphragm. And the counter electrode, and in a state where the working electrode and the counter electrode are in contact with the electrolyte contained in the chamber, the measurement target component that has passed through the diaphragm reacts on the surface of the working electrode. In an electrode regeneration apparatus to which a diaphragm type sensor for measuring a measurement current flowing between the working electrode and the counter electrode is connected,
An electrode regeneration apparatus comprising: a sensitivity return current generator for passing a sensitivity return current different from the measurement current to the working electrode.
JP2004210578A 2004-07-16 2004-07-16 Sensitivity restoring method of diaphragm type sensor, measuring instrument and electrode regeneration device Pending JP2006030027A (en)

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