JP2017161457A - Electrochemical sensor - Google Patents

Electrochemical sensor Download PDF

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JP2017161457A
JP2017161457A JP2016048459A JP2016048459A JP2017161457A JP 2017161457 A JP2017161457 A JP 2017161457A JP 2016048459 A JP2016048459 A JP 2016048459A JP 2016048459 A JP2016048459 A JP 2016048459A JP 2017161457 A JP2017161457 A JP 2017161457A
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gas
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reaction
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electrochemical sensor
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克典 近藤
Katsunori Kondo
克典 近藤
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New Cosmos Electric Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical gas sensor which can be reduced in size with a convenient structure.SOLUTION: An electrochemical sensor X stores, inside a cabinet 10, a gas electrode 20 for gas detection consisting of a reaction electrode 21 for the electrochemical reaction of gas to be detected, a reference electrode 22, and a counter electrode 23, in the stated order, and these gas electrodes 20 are stacked through a water retention member 40 that absorbs and retains an electrolyte 31.SELECTED DRAWING: Figure 1

Description

本発明は、筐体の内部に、反応極と、参照極と、対極と、これら電極に接する電解液と、を備えた電気化学式センサに関する。   The present invention relates to an electrochemical sensor including a reaction electrode, a reference electrode, a counter electrode, and an electrolytic solution in contact with these electrodes inside a housing.

電気化学式ガスセンサは、化学反応（酸化還元反応）によって発生するエネルギーを電気エネルギーとして取り出すことによって、ガスを検知するものである。電気化学式ガスセンサは、低消費電力、出力特性がリニア、ガス選択性に比較的優れるなどの特徴を持っていることから、工業用のガス濃度測定機器や、近年では一酸化炭素や硫化水素、酸素などの検知警報器などに広く使用されている。   The electrochemical gas sensor detects gas by taking out energy generated by a chemical reaction (oxidation-reduction reaction) as electric energy. Electrochemical gas sensors have features such as low power consumption, linear output characteristics, and relatively high gas selectivity, so they are used in industrial gas concentration measuring instruments, and in recent years carbon monoxide, hydrogen sulfide, and oxygen. Widely used in detection alarm devices.

一酸化炭素の場合、反応極で一酸化炭素の酸化反応がおき、それによって生成する水素イオンと等量の水素イオンが、対極で空気中の酸素と反応して水を生成する。この一連の反応によって発生する電流は、反応極側のガス濃度に対応するため、この電流を測定することでガス濃度を検知することができる。   In the case of carbon monoxide, an oxidation reaction of carbon monoxide occurs at the reaction electrode, and hydrogen ions equivalent to the hydrogen ions generated thereby react with oxygen in the air at the counter electrode to generate water. Since the current generated by this series of reactions corresponds to the gas concentration on the reaction electrode side, the gas concentration can be detected by measuring this current.

電気化学式ガスセンサは、開口部を設けた筐体と、小孔が形成された蓋部と、を備え、当該筐体の内部に、反応極、参照極、対極、電極を押圧固定するＯリング、電解液、ガス透過膜などがそれぞれ収容されている。   The electrochemical gas sensor includes a housing provided with an opening and a lid formed with a small hole, and an O-ring that presses and fixes a reaction electrode, a reference electrode, a counter electrode, and an electrode inside the housing, An electrolytic solution, a gas permeable membrane, and the like are accommodated.

上述した電気化学式ガスセンサにおいて、筐体を外側筐体および内側筐体で構成した二重構造とし、電解液を、外側筐体に内包した内側筐体に収容することがあった。この場合、外側筐体および内側筐体の隙間に、反応極、参照極および対極のそれぞれと各別に接続する導線を挿通させていた。   In the above-described electrochemical gas sensor, the casing may have a double structure including an outer casing and an inner casing, and the electrolytic solution may be contained in the inner casing included in the outer casing. In this case, a conducting wire connected to each of the reaction electrode, the reference electrode, and the counter electrode is inserted into the gap between the outer casing and the inner casing.

外側筐体は、底側に設けた孔部および前記底側の反対側に設けた開口部を有し、内側筐体は、当該孔部を挿通して電解液を内側筐体に注入可能な筒状部を有する。   The outer casing has a hole provided on the bottom side and an opening provided on the opposite side of the bottom side, and the inner casing can insert the electrolyte into the inner casing through the hole. It has a cylindrical part.

反応極、参照極および対極は、それぞれを撥水性を有する多孔質のガス透過膜に積層し、それぞれをグラスウール膜などで絶縁した状態でＯリングによって押圧固定されていた。当該Ｏリングは、外側筐体の開口部を封止する蓋部によって押圧されていた。   The reaction electrode, the reference electrode, and the counter electrode were each laminated on a porous gas permeable film having water repellency, and each of them was pressed and fixed by an O-ring while being insulated with a glass wool film or the like. The O-ring was pressed by a lid that seals the opening of the outer casing.

尚、このような電気化学式ガスセンサは一般的な技術であるため、従来技術は示さない。   In addition, since such an electrochemical gas sensor is a general technique, the prior art is not shown.

上述した電気化学式ガスセンサは、筐体を外側筐体および内側筐体で構成した二重構造とし、電解液を外側筐体に内包した内側筐体に収容する構造のため、複雑な構造となり、製造や電解液の注入が煩雑であった。   The above-described electrochemical gas sensor has a complicated structure because it has a double structure in which the case is composed of an outer case and an inner case, and the electrolytic solution is housed in the inner case enclosed in the outer case. And the injection of the electrolyte was complicated.

従って、本発明の目的は、簡便な構造で小型化できる電気化学式ガスセンサを提供することにある。   Accordingly, an object of the present invention is to provide an electrochemical gas sensor that can be miniaturized with a simple structure.

上記目的を達成するための本発明に係る電気化学式センサの第一特徴構成は、筐体の内部に、ガスを検知するガス電極として被検知ガスを電気化学反応させる反応極と、参照極と、対極と、をこの順に収容し、これらガス電極は、それぞれ電解液を吸水して保持する保水部材を介して積層した点にある。   In order to achieve the above object, the first characteristic configuration of the electrochemical sensor according to the present invention includes a reaction electrode for electrochemically reacting a gas to be detected as a gas electrode for detecting gas inside the housing, a reference electrode, The counter electrodes are accommodated in this order, and the gas electrodes are stacked through water retaining members that absorb and hold the electrolyte solution.

本構成によれば、反応極および参照極の間に保水部材を配設し、参照極および対極の間に保水部材を配設することができる。よって、各ガス電極を、保水部材が保持する電解液に接触させることができるため、電解液を収容した電解液収容空間を設ける必要がなくなる。従って、電気化学式ガスセンサを簡便な構造とすることができ、かつ小型化することができる。   According to this configuration, the water retention member can be disposed between the reaction electrode and the reference electrode, and the water retention member can be disposed between the reference electrode and the counter electrode. Therefore, each gas electrode can be brought into contact with the electrolyte solution held by the water retention member, and therefore it is not necessary to provide an electrolyte solution storage space for storing the electrolyte solution. Therefore, the electrochemical gas sensor can have a simple structure and can be miniaturized.

本発明に係る電気化学式センサの第二特徴構成は、前記反応極および前記対極の間にイオン交換膜を配設した点にある。   The second characteristic configuration of the electrochemical sensor according to the present invention is that an ion exchange membrane is disposed between the reaction electrode and the counter electrode.

本構成によれば、電解液を吸水して保持する保水部材が押圧力などによって破損した場合であっても、反応極および対極がショートするのを防止することができる。   According to this configuration, even when the water retaining member that absorbs and holds the electrolytic solution is damaged by the pressing force or the like, it is possible to prevent the reaction electrode and the counter electrode from being short-circuited.

本発明に係る電気化学式センサの第三特徴構成は、前記筐体を封止する蓋部材を備え、当該蓋部材に前記反応極を熱融着し、前記筐体の内部に設けた内部部材に前記対極を熱融着した点にある。   A third characteristic configuration of the electrochemical sensor according to the present invention is provided with a lid member that seals the casing, and the reaction electrode is heat-sealed to the lid member, and an internal member provided inside the casing is provided. The counter electrode is heat-sealed.

本構成によれば、反応極、対極および参照極をＯリングなどによって押圧固定する必要が無くなり、センサを組み立てる際の部品数を減じることができる。これにより、より簡便な構造のセンサとすることができる。   According to this configuration, it is not necessary to press and fix the reaction electrode, the counter electrode, and the reference electrode with an O-ring or the like, and the number of parts when assembling the sensor can be reduced. Thereby, it can be set as the sensor of a simpler structure.

本発明に係る電気化学式センサの第四特徴構成は、当該蓋部材および前記筐体の底面のそれぞれにピンホールを形成した筒部材を配設した点にある。   A fourth characteristic configuration of the electrochemical sensor according to the present invention is that a cylindrical member in which a pinhole is formed in each of the lid member and the bottom surface of the housing is provided.

本構成によれば、例えば蓋部材に形成した筒部材をガスの導入部とし、筐体の底面に形成した筒部材をガスの排出部とすることができ、ガスの導入部および排出部をピンホールを形成した筒部材とすることができる。当該ピンホールの孔径は検知対象とするガス種に応じて適宜決定することでガスの選択性を持たせることができる。このようにガスの導入部および排出部を小径とすることでセンサの内部に干渉ガス等が混入し難くなり、干渉ガスによる影響や、外部の温湿度等による環境変化の影響を受け難くなる。   According to this configuration, for example, the cylindrical member formed on the lid member can be used as the gas introduction unit, and the cylindrical member formed on the bottom surface of the housing can be used as the gas discharge unit. It can be set as the cylinder member which formed the hole. The hole diameter of the pinhole can be given gas selectivity by appropriately determining according to the gas type to be detected. Thus, by making the gas introduction part and the discharge part have a small diameter, it becomes difficult for the interference gas or the like to be mixed into the sensor, and it is difficult to be influenced by the interference gas or the environmental change due to the external temperature and humidity.

本発明に係る電気化学式センサの第五特徴構成は、前記蓋部材におけるガス導入部および前記反応極の間に結露・圧力緩和膜を配設した点にある。   A fifth characteristic configuration of the electrochemical sensor according to the present invention resides in that a dew condensation / pressure relaxation film is disposed between the gas introduction part and the reaction electrode in the lid member.

本構成によれば、結露・圧力緩和膜を備えることで、微細なピンホールを有するガス導入部において結露が発生し難くなり、被検知ガスをセンサの内部に導入できなくなるのを未然に防止でき、かつ圧力依存を緩和するためセンサ周囲及びセンサ内部の圧力上昇や低下（特に突発的な圧力変動）を緩和することができ、指示値も安定する。   According to this configuration, by providing the condensation / pressure relief film, it is difficult for condensation to occur in the gas introduction part having a fine pinhole, and it is possible to prevent the gas to be detected from being introduced into the sensor. In addition, since the pressure dependence is relaxed, the pressure increase or decrease (especially sudden pressure fluctuation) around the sensor and inside the sensor can be mitigated, and the indicated value is also stabilized.

本発明の電気化学式センサの概略を示す断面図である。It is sectional drawing which shows the outline of the electrochemical type sensor of this invention. 電気化学式センサの上面視概略図である。It is a top view schematic diagram of an electrochemical sensor. 電気化学式センサの側面視概略図である。It is a schematic side view of an electrochemical sensor. 電気化学式センサの下面視概略図である。It is a bottom view schematic diagram of an electrochemical sensor. 本発明の電気化学式センサを示す分解図である。It is an exploded view which shows the electrochemical type sensor of this invention. 電気化学式センサの別実施形態１の概略を示す断面図である。It is sectional drawing which shows the outline of another Embodiment 1 of an electrochemical sensor. 電気化学式センサの別実施形態２の概略を示す断面図である。It is sectional drawing which shows the outline of another Embodiment 2 of an electrochemical sensor. 酸素ガスを検知した場合の応答速度を調べた結果を示したグラフである。It is the graph which showed the result of having investigated the response speed at the time of detecting oxygen gas. 酸素ガスを検知した場合の直線性を調べた結果を示したグラフである。It is the graph which showed the result of having investigated the linearity at the time of detecting oxygen gas. 酸素ガスを検知した場合の経時安定性を調べた結果を示したグラフである。It is the graph which showed the result of having investigated the temporal stability at the time of detecting oxygen gas.

以下、本発明の実施形態を図面に基づいて説明する。
図１〜５に示したように、本発明の電気化学式センサＸは、筐体１０の内部に、ガスを検知するガス電極２０として被検知ガスを電気化学反応させる反応極２１と、参照極２２と、対極２３と、をこの順に収容し、これらガス電極２１〜２３は、それぞれ電解液３１を吸水して保持する保水部材４０を介して積層してある。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 5, an electrochemical sensor X of the present invention includes a reaction electrode 21 that causes a gas to be detected to electrochemically react as a gas electrode 20 that detects gas, and a reference electrode 22 inside a housing 10. The counter electrode 23 is accommodated in this order, and the gas electrodes 21 to 23 are stacked via a water retention member 40 that absorbs and holds the electrolytic solution 31.

ガス電極２０は筐体１０の内部に形成された電極収容部１０ａに収容される。電極収容部１０ａは、筐体１０と、当該筐体１０に形成された開口部１０ｂを封止する蓋部材１１とで囲まれた空間となる。筐体１０および蓋部材１１は、例えばプラスティックなどの樹脂製とすることができ、この場合、これらを公知の接着剤や超音波融着などによって固定することができるが、これらに限定されるものではない。   The gas electrode 20 is housed in an electrode housing portion 10 a formed inside the housing 10. The electrode housing portion 10 a is a space surrounded by the housing 10 and the lid member 11 that seals the opening 10 b formed in the housing 10. The housing 10 and the lid member 11 can be made of resin such as plastic, for example, and in this case, they can be fixed by a known adhesive or ultrasonic fusion, but are not limited thereto. is not.

反応極２１、参照極２２および対極２３は、触媒および疎水性樹脂を含むガス拡散電極からなり、触媒としては、白金（Ｐｔ）、金（Ａｕ）、ルテニウム（Ｒｕ）、酸化ルテニウム（ＲｕＯ２）、パラジウム（Ｐｄ）、カーボン（Ｃ）、白金担時カーボン（Ｐｔ／Ｃ）、金担時カーボン（Ａｕ／Ｃ）などが好適に用いられ、疎水性樹脂としてはポリテトラフルオロエチレン（ＰＴＦＥ）樹脂などが好適に用いられる。 The reaction electrode 21, the reference electrode 22 and the counter electrode 23 are composed of a gas diffusion electrode containing a catalyst and a hydrophobic resin. As the catalyst, platinum (Pt), gold (Au), ruthenium (Ru), ruthenium oxide (RuO 2 ). Palladium (Pd), carbon (C), platinum-supported carbon (Pt / C), gold-supported carbon (Au / C), etc. are preferably used, and polytetrafluoroethylene (PTFE) resin as the hydrophobic resin Etc. are preferably used.

反応極２１、参照極２２および対極２３は、それぞれ撥水性を有する多孔質（ＰＴＦＥ製）のガス透過膜５１〜５３に積層してある。   The reaction electrode 21, the reference electrode 22, and the counter electrode 23 are laminated on porous (perforated PTFE) gas permeable membranes 51 to 53 each having water repellency.

ガス透過膜５１〜５３は、電解液３１の浸入を防止し、かつ被検知ガスを透過する材質であればよく、例えばポリテトラフルオロエチレン等、従来公知のものが適用可能である。   The gas permeable membranes 51 to 53 may be made of any material that prevents the electrolyte solution 31 from entering and allows the gas to be detected to pass therethrough, and conventionally known materials such as polytetrafluoroethylene are applicable.

電解液３１は、吸水性の保水部材４０に保持され、その周囲にも存在する。保水部材４０は、電解液３１を吸水して保持する態様であるため、その内部に電解液３１を保持できる空間を有する。保水部材４０は、例えば濾紙状のガラス繊維や、セルロース繊維、セラミックス繊維、吸水性の高分子、グラスウール等で構成することができ、電解液３１を保持できる吸水性の部材であれば、特に限定されるものではない。この保水部材４０には、電解質として、硫酸（Ｈ２ＳＯ４）やリン酸（Ｈ３ＰＯ４）などの酸性水溶液、水酸化カリウム（ＫＯＨ）、水酸化ナトリウム（ＮａＯＨ）などのアルカリ性水溶液、常温溶融塩が充分に含浸されている。 The electrolytic solution 31 is held by the water-absorbing water retaining member 40 and is also present in the vicinity thereof. Since the water retaining member 40 is an aspect in which the electrolytic solution 31 is absorbed and retained, the water retaining member 40 has a space in which the electrolytic solution 31 can be retained. The water retaining member 40 can be made of, for example, filter paper-like glass fiber, cellulose fiber, ceramic fiber, water-absorbing polymer, glass wool, or the like, and is particularly limited as long as it is a water-absorbing member that can hold the electrolytic solution 31. Is not to be done. The water retaining member 40 includes, as an electrolyte, an acidic aqueous solution such as sulfuric acid (H 2 SO 4 ) and phosphoric acid (H 3 PO 4 ), an alkaline aqueous solution such as potassium hydroxide (KOH) and sodium hydroxide (NaOH), The molten salt is sufficiently impregnated.

常温溶融塩としては、常温において液体状態となる、主に窒素含有芳香族カチオンもしくは脂肪族オニウムカチオンとフッ素含有アニオンとから構成される溶融塩が用いられる。当該窒素含有芳香族カチオンとしては、例えばアルキルイミダゾリウムイオンまたはアルキルピリジニウムイオンが用いられる。また上記フッ素含有アニオンは、例えばホウフッ化物イオン、リンフッ化物イオンまたはトリフルオロメタンスルホン酸イオンが用いられる。   As the room temperature molten salt, a molten salt mainly composed of a nitrogen-containing aromatic cation or aliphatic onium cation and a fluorine-containing anion that is in a liquid state at room temperature is used. As the nitrogen-containing aromatic cation, for example, an alkyl imidazolium ion or an alkyl pyridinium ion is used. As the fluorine-containing anion, for example, borofluoride ion, phosphorous fluoride ion or trifluoromethanesulfonate ion is used.

電解液３１は、予め保水部材４０に保持させた状態とし、この保水部材４０を筐体１０の内部に配設してセンサを組み立ててもよいし、センサを組み立てた後に、筐体１０に開口させた注入孔（図外）から電解液３１を保水部材４０に保持させるようにしてもよい。この場合、電解液３１を注入した後、熱溶着により注入孔を封止するように構成すればよい。   The electrolytic solution 31 may be held in the water retaining member 40 in advance, and the water retaining member 40 may be disposed inside the housing 10 to assemble the sensor, or the sensor 10 may be assembled and then opened to the housing 10. The electrolyte solution 31 may be held by the water retaining member 40 from the injection hole (not shown). In this case, after injecting the electrolytic solution 31, the injection hole may be sealed by heat welding.

電気化学式センサＸは、反応極２１、参照極２２および対極２３のそれぞれと各別に接続する複数の導線６０を備える。導線６０は、白金、金およびニッケル等で形成すればよい。また、導線６０は、各ガス電極２０と導通するものであれば特にその形状などは限定されないが、各ガス電極２０との接触面積をより広くし、より確実な導通を実現するという点から、例えばリボン状、帯状等の幅広形状とするのがよい。筐体１０における端子設置穴１２に、各ガス電極２０と各別に接続する導線６０に接続する電極端子１３を複数備える。   The electrochemical sensor X includes a plurality of conductive wires 60 connected to the reaction electrode 21, the reference electrode 22, and the counter electrode 23, respectively. The conducting wire 60 may be formed of platinum, gold, nickel, or the like. Further, the shape of the conductive wire 60 is not particularly limited as long as it is electrically connected to each gas electrode 20, but the contact area with each gas electrode 20 is widened to realize more reliable conduction. For example, a wide shape such as a ribbon shape or a belt shape is preferable. The terminal installation hole 12 in the housing 10 is provided with a plurality of electrode terminals 13 that are connected to the gas wires 20 and the conductive wires 60 that are connected separately.

本実施形態では、蓋部材１１の側から順に反応極２１、参照極２２および対極２３を配設し、反応極２１および参照極２２の間に保水部材４０を配設し、参照極２２および対極２３の間に保水部材４０を配設している。   In the present embodiment, the reaction electrode 21, the reference electrode 22, and the counter electrode 23 are disposed in this order from the lid member 11 side, the water retention member 40 is disposed between the reaction electrode 21 and the reference electrode 22, and the reference electrode 22 and the counter electrode are disposed. A water retaining member 40 is disposed between the two.

これにより、各ガス電極２０を、保水部材４０が保持する電解液３１に接触させることができるため、電解液を収容した電解液収容空間を設ける必要がなくなる。従って、電気化学式ガスセンサを簡便な構造とすることができ、かつ小型化することができる。   Thereby, since each gas electrode 20 can be made to contact the electrolyte solution 31 which the water retention member 40 hold | maintains, it becomes unnecessary to provide the electrolyte solution accommodation space which accommodated the electrolyte solution. Therefore, the electrochemical gas sensor can have a simple structure and can be miniaturized.

また、反応極２１および対極２３の間にイオン交換膜７０を配設することができる。本実施形態では、イオン交換膜７０を、参照極２２および対極２３の間に、保水部材４０に挟まれた態様について説明する。この場合、当該イオン交換膜７０は、その両面を二枚の保水部材４０に挟まれた態様で配設することができる。   Further, an ion exchange membrane 70 can be disposed between the reaction electrode 21 and the counter electrode 23. In the present embodiment, a mode in which the ion exchange membrane 70 is sandwiched between the reference electrode 22 and the counter electrode 23 and the water retaining member 40 will be described. In this case, the ion exchange membrane 70 can be disposed in such a manner that both surfaces thereof are sandwiched between the two water retaining members 40.

電解液３１が塩基性水溶液の場合はアニオン交換膜を使用することができ、酸性水溶液の場合はカチオン交換膜を使用すればよい。イオン交換膜７０は、具体的にはナフィオン（登録商標：デュポン社製）、アシプレックス（登録商標：旭化成社製）、フレミオン（登録商標：旭硝子社製）、ユアサグラフト膜（ユアサメンブレンシステム社製）などを使用することができるが、これらに限定されるものではない。   When the electrolytic solution 31 is a basic aqueous solution, an anion exchange membrane can be used, and when the electrolytic solution 31 is an acidic aqueous solution, a cation exchange membrane may be used. Specifically, the ion exchange membrane 70 includes Nafion (registered trademark: manufactured by DuPont), Aciplex (registered trademark: manufactured by Asahi Kasei), Flemion (registered trademark: manufactured by Asahi Glass), Yuasa graft membrane (manufactured by Yuasa Membrane System). ) And the like can be used, but is not limited thereto.

本構成であれば、反応極２１および対極２３の間にイオン交換膜７０を配設することができるため、電解液３１を吸水して保持する保水部材４０が押圧力などによって破損した場合であっても、反応極２１および対極２３がショートするのを防止することができる。尚、当該押圧力としては、例えば反応極２１、参照極２２および対極２３を、それぞれ電解液を吸水して保持する保水部材を介して積層した状態において蓋部材１１によって筐体１０を封止した場合に生じる圧力などが考えられる。   With this configuration, since the ion exchange membrane 70 can be disposed between the reaction electrode 21 and the counter electrode 23, the water retention member 40 that absorbs and holds the electrolytic solution 31 is damaged by a pressing force or the like. However, it is possible to prevent the reaction electrode 21 and the counter electrode 23 from being short-circuited. As the pressing force, for example, the casing 10 is sealed by the lid member 11 in a state where the reaction electrode 21, the reference electrode 22, and the counter electrode 23 are stacked via a water retention member that absorbs and holds the electrolytic solution, respectively. The pressure generated in the case is considered.

本実施形態では、三枚の保水部材４０、即ち、反応極２１および参照極２２の間に配設した第一保水部材４１、参照極２２および対極２３の間に配設した保水部材４０のうち、上方にある第二保水部材４２、および、下方にある第三保水部材４３、を使用しているが、これらの厚さや嵩密度等は同じとしてもよいし、異ならせてもよい。例えば厚さについては、本実施形態では第一保水部材４１および第三保水部材４３を厚く（１ｍｍ程度のガラス繊維濾紙：ワットマンＧＷ（ワットマンジャパン株式会社））、第二保水部材４２を薄く（０．５ｍｍ程度のガラス繊維濾紙（アドバンテック東洋株式会社製））する場合を例示するが、これに限定されるものではない。   In the present embodiment, among the three water retaining members 40, that is, the first water retaining member 41 disposed between the reaction electrode 21 and the reference electrode 22, and the water retaining member 40 disposed between the reference electrode 22 and the counter electrode 23. Although the upper second water retaining member 42 and the lower third water retaining member 43 are used, the thickness, bulk density, and the like thereof may be the same or different. For example, regarding the thickness, in the present embodiment, the first water retaining member 41 and the third water retaining member 43 are thick (about 1 mm glass fiber filter paper: Whatman GW (Whatman Japan Co., Ltd.)), and the second water retaining member 42 is thin (0 The glass fiber filter paper (made by Advantech Toyo Co., Ltd.) of about 5 mm is exemplified, but the present invention is not limited to this.

本実施形態では、筐体１０を封止する蓋部材１１において、反応極２１を熱融着してある場合について説明する。   In the present embodiment, the case where the reaction electrode 21 is thermally fused in the lid member 11 that seals the housing 10 will be described.

上述したように、筐体１０および蓋部材１１を樹脂製とした場合、反応極２１を３００〜４００℃程度の温度で蓋部材１１に熱融着することができる。当該熱融着は、蓋部材１１を樹脂の種類や、反応極２１使用するガス透過膜５１〜５３の種類により設定される温度によって適宜決定されるので、この温度範囲に限定されるものではない。   As described above, when the housing 10 and the lid member 11 are made of resin, the reaction electrode 21 can be heat-sealed to the lid member 11 at a temperature of about 300 to 400 ° C. The heat fusion is appropriately determined depending on the temperature set according to the type of resin used for the lid member 11 and the type of the gas permeable membranes 51 to 53 using the reaction electrode 21, and is not limited to this temperature range. .

本構成であれば、反応極２１をＯリングなどによって押圧固定する必要が無くなり、センサを組み立てる際の部品数を減じることができる。これにより、より簡便な構造のセンサとすることができる。   With this configuration, it is not necessary to press and fix the reaction electrode 21 with an O-ring or the like, and the number of parts when assembling the sensor can be reduced. Thereby, it can be set as the sensor of a simpler structure.

尚、本実施形態では、反応極２１を蓋部材１１に熱融着した後、ナフィオン溶液を反応極２１に塗布する態様とする。塗布するナフィオン溶液の濃度は５〜２０ｗｔ％とすることができるが、これに限定されるものではない。参照極２２および対極２３に対してはナフィオン溶液を塗布するのが好ましい。   In the present embodiment, the reaction electrode 21 is thermally fused to the lid member 11 and then the Nafion solution is applied to the reaction electrode 21. The concentration of the Nafion solution to be applied can be 5 to 20 wt%, but is not limited thereto. A Nafion solution is preferably applied to the reference electrode 22 and the counter electrode 23.

また、本実施形態では、当該蓋部材１１に形成した貫通孔であるガス導入部１１ａに、ピンホール１４ａを形成した筒部材１４を配設してある場合について説明する。尚、図２の電気化学式センサＸの上面視概略図は、ピンホール１４ａを形成した筒部材１４の態様を認識できるように結露・圧力緩和膜８０、活性炭繊維９１および防塵フィルター９２（後述）は示していない。   Further, in the present embodiment, a case will be described in which a cylindrical member 14 having a pinhole 14a is disposed in a gas introduction portion 11a that is a through hole formed in the lid member 11. In addition, the schematic top view of the electrochemical sensor X in FIG. 2 shows the dew condensation / pressure relaxation membrane 80, the activated carbon fiber 91, and the dustproof filter 92 (described later) so that the aspect of the cylindrical member 14 in which the pinhole 14a is formed can be recognized. Not shown.

筒部材１４は、例えばアルミナ、ジルコニア等のセラミックスが挙げられるが、これらに限定されるものではない。筒部材１４の長寸は１．５ｍｍ以上であり、好ましくは１．５〜５．６ｍｍとするのがよい。また、ピンホール１４ａの孔径は検知対象とするガス種に応じて適宜決定できるが、０．０５〜０．１０ｍｍ程度とするのがよい。   Examples of the cylindrical member 14 include ceramics such as alumina and zirconia, but are not limited thereto. The long dimension of the cylindrical member 14 is 1.5 mm or more, preferably 1.5 to 5.6 mm. Moreover, although the hole diameter of the pinhole 14a can be suitably determined according to the gas kind made into a detection target, it is good to set it as about 0.05-0.10 mm.

ガス導入部１１ａに筒部材１４を配設した後、ピンホール１４ａ以外の気密性を確保するため公知の接着剤あるいはパッキンなどの封止手段１５で封止するとよい。   After the cylindrical member 14 is disposed in the gas introduction part 11a, sealing may be performed with a sealing means 15 such as a known adhesive or packing in order to ensure airtightness other than the pinhole 14a.

このようにガスの導入部をピンホール１４ａのように小径とすることでセンサの内部に干渉ガス等が混入し難くなり、干渉ガスによる影響や、外部の温湿度等による環境変化の影響を受け難くなる。   In this way, by making the gas introduction part as small as the pinhole 14a, it becomes difficult for the interference gas or the like to enter the inside of the sensor, and it is affected by the influence of the interference gas or the environmental change due to the external temperature and humidity. It becomes difficult.

また、筐体１０における蓋部材１１とは反対側の底面１０ｃに形成した貫通孔である底面貫通孔１１ｂにおいても、ピンホール１６ａを形成した筒部材１６を配設してある。尚、図４の電気化学式センサＸの下面視概略図は、ピンホール１６ａを形成した筒部材１６の態様を認識できるように防塵フィルター９２（後述）は示していない。   In addition, the cylindrical member 16 in which the pinhole 16a is formed is also disposed in the bottom surface through hole 11b which is a through hole formed in the bottom surface 10c opposite to the lid member 11 in the housing 10. In addition, the bottom view schematic diagram of the electrochemical sensor X in FIG. 4 does not show a dustproof filter 92 (described later) so that the aspect of the cylindrical member 16 in which the pinhole 16a is formed can be recognized.

これら筒部材１６およびピンホール１６ａは、筒部材１４およびピンホール１４ａと同様の構成とすることができるが、筒部材１６の長寸は２．０ｍｍ以上であり、好ましくは２．５〜３．５ｍｍとするのがよい。底面貫通孔１１ｂからは、検知対象となるガス種により、センサ内部の酸素等のガスを排出する場合や、外気からの酸素を供給することができる。また、ピンホール１６ａの径もピンホール１４ａと同様に小径にすることで、センサの内部に干渉ガス等が混入し難くなり、干渉ガスによる影響や、外部の温湿度等による環境変化の影響を受け難くなる。
尚、底面貫通孔１１ｂは、検知ガス種に応じてガス排出部、あるいはガス導入部になり得る。 The cylindrical member 16 and the pinhole 16a can have the same configuration as the cylindrical member 14 and the pinhole 14a, but the length of the cylindrical member 16 is 2.0 mm or more, preferably 2.5-3. 5 mm is preferable. From the bottom through-hole 11b, depending on the type of gas to be detected, oxygen or other gas inside the sensor can be discharged, or oxygen from outside air can be supplied. In addition, by making the diameter of the pinhole 16a as small as the pinhole 14a, it becomes difficult for the interference gas or the like to be mixed into the inside of the sensor, and the influence of the interference gas or the environmental change due to the external temperature and humidity etc. It becomes difficult to receive.
The bottom through-hole 11b can be a gas discharge part or a gas introduction part depending on the detected gas type.

この場合も、底面貫通孔１１ｂに筒部材１６を配設した後、ピンホール１６ａ以外の気密性を確保するため公知の接着剤９０で封止するとよい。   Also in this case, after the cylindrical member 16 is disposed in the bottom through-hole 11b, it is preferable to seal with a known adhesive 90 in order to ensure airtightness other than the pinhole 16a.

対極２３およびガス透過膜５３の固定については、筐体１０の内部に設けた内部部材１９を配設して固定してある。この場合、当該内部部材１９に対して対極２３およびガス透過膜５３を熱融着により固定することができる。内部部材１９は、接着剤９０によって筐体１０の底面１０ｃに接着すればよい。本実施形態では内部部材１９は例えば樹脂製のドーナツ型の態様とし、内部部材１９の中心の開口部１９ａには筒部材１６を挿通させる場合について説明する。   The counter electrode 23 and the gas permeable membrane 53 are fixed by disposing and fixing the internal member 19 provided inside the housing 10. In this case, the counter electrode 23 and the gas permeable membrane 53 can be fixed to the internal member 19 by heat fusion. The internal member 19 may be bonded to the bottom surface 10 c of the housing 10 with the adhesive 90. In the present embodiment, the case where the internal member 19 has a resin donut shape, for example, and the cylindrical member 16 is inserted through the opening 19a at the center of the internal member 19 will be described.

蓋部材１１におけるガス導入部１１ａおよび反応極２１の間には、結露・圧力緩和膜８０を配設してもよい。結露・圧力緩和膜８０は、結露を防ぐ膜であり、ガスを透過して液体を透過しない性質を有するものであればどのような膜でもよく、多孔質ＰＴＦＥ膜などを使用することができる。   A dew condensation / pressure relaxation film 80 may be disposed between the gas introduction part 11 a and the reaction electrode 21 in the lid member 11. The dew condensation / pressure relaxation film 80 is a film that prevents dew condensation, and any film may be used as long as it has a property of allowing gas to permeate but not liquid, and a porous PTFE film or the like can be used.

本実施形態の結露・圧力緩和膜８０は厚さ０．２ｍｍ程度で、その特性は、例えば透気度がガーレー値で２００〜７００程度、空孔率が３５〜４５％、ＷＥＰ（水の侵入圧力）が１９６ｋＰａ以上、好ましくは５００ｋＰａとするのがよい。   The dew condensation / pressure relaxation film 80 of this embodiment has a thickness of about 0.2 mm, and its characteristics are, for example, an air permeability of about 200 to 700 in terms of Gurley value, a porosity of 35 to 45%, and WEP (water intrusion). The pressure) is 196 kPa or more, preferably 500 kPa.

結露・圧力緩和膜８０はガス導入部１１ａおよび反応極２１の間に配設だけでなく、さらにガス導入部１１ａの雰囲気側（反応極２１の反対側）にも配設することができる。
また、結露・圧力緩和膜８０は、ガス導入部１１ａに限らず、底面貫通孔１１ｂおよび対極２３の間に配設することができる。この場合においては、底面貫通孔１１ｂにおける結露の発生を未然に防止することができる。 The dew condensation / pressure relaxation film 80 can be disposed not only between the gas introduction part 11 a and the reaction electrode 21 but also on the atmosphere side of the gas introduction part 11 a (opposite to the reaction electrode 21).
Further, the dew condensation / pressure relaxation film 80 is not limited to the gas introduction part 11 a but can be disposed between the bottom surface through hole 11 b and the counter electrode 23. In this case, it is possible to prevent condensation from occurring in the bottom through-hole 11b.

結露・圧力緩和膜８０は、当該膜が設けられたガス導入部１１ａ（ガス導入部１１ａおよび反応極２１の間、ガス導入部１１ａの雰囲気側）における結露の発生を未然に防止することができる。周囲の環境変化に伴って、例えばガス導入部１１ａにおいて結露が発生した場合、被検知ガスをセンサの内部に導入できない虞がある。また、当該結露によってガス導入部１１ａを塞いだ場合、センサ内部の圧力が抜け難くなって指示値のゆらぎが大きくなる虞がある。また、これらが完全に塞がってしまった場合、指示値がゼロになる虞がある。しかし、結露・圧力緩和膜８０を備えることで、微細なピンホール１４ａを有するガス導入部１１ａにおいて結露が発生し難くなり、被検知ガスをセンサの内部に導入できなくなるのを未然に防止でき、かつ圧力依存を緩和するためセンサ周囲及びセンサ内部の圧力上昇や低下（特に突発的な圧力変動）を緩和することができ、指示値も安定する。   The dew condensation / pressure relaxation film 80 can prevent the occurrence of dew condensation in the gas introduction part 11a (between the gas introduction part 11a and the reaction electrode 21 and the atmosphere side of the gas introduction part 11a) provided with the film. . For example, when dew condensation occurs in the gas introduction part 11a with the surrounding environment change, there is a possibility that the gas to be detected cannot be introduced into the sensor. Moreover, when the gas introduction part 11a is blocked by the condensation, there is a possibility that the pressure inside the sensor is difficult to be released and the fluctuation of the indicated value becomes large. Moreover, when these are completely blocked, there is a possibility that the indicated value becomes zero. However, by providing the dew condensation / pressure relaxation film 80, it is difficult for condensation to occur in the gas introduction part 11a having the fine pinhole 14a, and it is possible to prevent the gas to be detected from being introduced into the sensor. In addition, since the pressure dependence is relaxed, the pressure increase or decrease (especially sudden pressure fluctuation) around the sensor and inside the sensor can be mitigated, and the indicated value is also stabilized.

ガス導入部１１ａにおける結露・圧力緩和膜８０の雰囲気側には活性炭繊維９１を配設し、その外方にはセンサ内部に塵や埃などが侵入するのを防止する防塵フィルター９２を配設してもよい。当該防塵フィルター９２は、底面貫通孔１１ｂの側にも配設してもよい。   An activated carbon fiber 91 is disposed on the atmosphere side of the dew condensation / pressure relaxation film 80 in the gas introduction part 11a, and a dustproof filter 92 for preventing dust and dirt from entering the sensor is disposed outside the activated carbon fiber 91. May be. The dust filter 92 may also be disposed on the bottom through hole 11b side.

本実施形態では、小型化が実現できる電気化学式センサＸの構成を説明した。具体的なセンサの部材のサイズは、例えば、反応極２１は直径５ｍｍ程度、参照極２２は直径７ｍｍ程度、対極２３は直径７〜１０ｍｍ程度、イオン交換膜７０（ナフィオン膜）は直径７ｍｍ程度、厚さ５０〜１８０μｍ程度、第一保水部材４１および第三保水部材４３は直径１０ｍｍ程度、第二保水部材４２は直径８〜１０ｍｍ程度とすることができるが、これらのサイズに限定されるものではない。また、本発明の電気化学式センサＸは、被検知ガスとして酸素ガスを検知するのに利用することができるが、これに限定されるものではない。   In the present embodiment, the configuration of the electrochemical sensor X that can be miniaturized has been described. Specific sensor member sizes include, for example, a reaction electrode 21 having a diameter of about 5 mm, a reference electrode 22 having a diameter of about 7 mm, a counter electrode 23 having a diameter of about 7 to 10 mm, and an ion exchange membrane 70 (Nafion membrane) having a diameter of about 7 mm. The thickness of the first water retaining member 41 and the third water retaining member 43 can be about 10 mm in diameter, and the second water retaining member 42 can be about 8 to 10 mm in diameter, but is not limited to these sizes. Absent. The electrochemical sensor X of the present invention can be used to detect oxygen gas as a gas to be detected, but is not limited to this.

〔別実施の形態１〕
上述した実施形態では、イオン交換膜７０を、参照極２２および対極２３の間に、保水部材４０に挟まれた態様の場合について説明した。しかし、このような態様に限定されるものではなく、図６に示したように、反応極２１および参照極２２の間に、保水部材４０およびイオン交換膜７０を配設し、当該イオン交換膜７０が参照極２２の側となるように配設してもよい。また、当該イオン交換膜７０はそれに限定されるものではなく、ＰＥＴ、ＰＥＮ、ＰＩ等のプラスチック製の膜であってもよい。 [Another embodiment 1]
In the above-described embodiment, the case where the ion exchange membrane 70 is sandwiched between the reference electrode 22 and the counter electrode 23 and the water retaining member 40 has been described. However, the present invention is not limited to such an embodiment. As shown in FIG. 6, a water retention member 40 and an ion exchange membrane 70 are disposed between the reaction electrode 21 and the reference electrode 22, and the ion exchange membrane. You may arrange | position so that 70 may become the reference pole 22 side. In addition, the ion exchange membrane 70 is not limited thereto, and may be a membrane made of plastic such as PET, PEN, and PI.

本実施形態では、二枚の保水部材４０、即ち、反応極２１および参照極２２の間に配設した第一保水部材４１、参照極２２および対極２３の間に配設した第二保水部材４２、を使用している。これにより、三枚の保水部材４０を使用した上述の実施形態より電解液３１の量を減少させることができるため、センサ内部の圧力上昇による電解液３１の液漏れのリスクを減じることができる。   In the present embodiment, the two water retention members 40, that is, the first water retention member 41 disposed between the reaction electrode 21 and the reference electrode 22, and the second water retention member 42 disposed between the reference electrode 22 and the counter electrode 23. , Are using. Thereby, since the quantity of the electrolyte solution 31 can be reduced from the above-mentioned embodiment using the three water retention members 40, the risk of the electrolyte solution 31 leaking due to a pressure increase inside the sensor can be reduced.

本実施形態においては、参照極２２は下向きの状態で配設したが、反応極２１および参照極２２の間に保水部材４１およびイオン交換膜７０を配設するときには、保水部材４０を二枚にする事ができ、より簡略化された構造となる（図６）。また、参照極２２を上向きに配設してもよく、この場合はイオン交換膜７０が保水部材４０で挟み込まれる形状となる。この場合、反応極２１と参照極２２の間の保水部材４１が破損した場合のショートを防止することが可能となる。
イオン交換膜７０を参照極２２の上下どちらかに設置する目的は、ショート防止以外には、参照極２２とリード線６０の接触を強固にすることが挙げられる。反応極２１、対極２３は片面が樹脂に融着されているので中間にある参照極２２よりもコシがあるため、コシのあるイオン交換膜７０を参照極２２の上下どちらかに設置することにより圧縮時の接触力を改善することができる。 In the present embodiment, the reference electrode 22 is disposed in a downward state. However, when the water retention member 41 and the ion exchange membrane 70 are disposed between the reaction electrode 21 and the reference electrode 22, the water retention member 40 is divided into two sheets. This results in a simplified structure (FIG. 6). Further, the reference electrode 22 may be disposed upward. In this case, the ion exchange membrane 70 is sandwiched between the water retention members 40. In this case, it is possible to prevent a short circuit when the water retaining member 41 between the reaction electrode 21 and the reference electrode 22 is damaged.
The purpose of installing the ion exchange membrane 70 either above or below the reference electrode 22 is to strengthen the contact between the reference electrode 22 and the lead wire 60 in addition to preventing a short circuit. Since the reaction electrode 21 and the counter electrode 23 are fused on one side to the resin, the reaction electrode 21 and the counter electrode 23 are stiffer than the reference electrode 22 in the middle. Therefore, by installing a stiff ion exchange membrane 70 on either the top or bottom of the reference electrode 22 The contact force during compression can be improved.

また、電解液３１を吸水して保持する保水部材４０が押圧力などによって破損した場合であっても、参照極２２が上向きの場合、反応極と参照極がショートすることを防止する事が可能となる。   Further, even when the water retaining member 40 that absorbs and holds the electrolytic solution 31 is damaged by a pressing force or the like, it is possible to prevent the reaction electrode and the reference electrode from being short-circuited when the reference electrode 22 faces upward. It becomes.

尚、本実施形態においては、対極２３の直径を１０ｍｍとし、結露・圧力緩和膜８０を底面貫通孔１１ｂおよび対極２３の間となるように構成した場合を示した。また、本実施形態においては、イオン交換膜７０は、省略して構成してもよい。   In the present embodiment, the counter electrode 23 has a diameter of 10 mm, and the dew condensation / pressure relaxation film 80 is configured to be between the bottom through-hole 11b and the counter electrode 23. In the present embodiment, the ion exchange membrane 70 may be omitted.

〔別実施の形態２〕
図７に示したように、上述した実施形態において内部部材１９を設けず、底面貫通孔１１ｂに筒部材１６を配設した後、ピンホール１６ａ以外の気密性を確保するため公知の接着剤あるいはパッキンなどの封止手段１７で封止してもよい。尚、封止手段１７の上面には、両面テープ等の公知の固着部材１８を配して対極２３を備えたガス透過膜５３固定してもよい。
また、図７では、ガス導入部１１ａの側における結露・圧力緩和膜８０、活性炭繊維９１および防塵フィルター９２を省略し、底面貫通孔１１ｂの側における防塵フィルター９２を省略した態様について示してある。 [Another embodiment 2]
As shown in FIG. 7, in the above-described embodiment, the internal member 19 is not provided, and after arranging the cylindrical member 16 in the bottom through-hole 11b, a known adhesive or the like is used to ensure airtightness other than the pinhole 16a. You may seal with sealing means 17, such as packing. It should be noted that a known fixing member 18 such as a double-sided tape may be disposed on the upper surface of the sealing means 17 to fix the gas permeable membrane 53 having the counter electrode 23.
Further, FIG. 7 shows a mode in which the dew condensation / pressure relaxation film 80, the activated carbon fiber 91, and the dustproof filter 92 on the gas introduction part 11a side are omitted, and the dustproof filter 92 on the bottom surface through hole 11b side is omitted.

〔実施例１〕
本発明の実施例について説明する。
本発明の電気化学式センサＸを図１のようにして構成した。
即ち、本実施例の電気化学式センサＸは、反応極２１は直径５ｍｍ、参照極２２は直径７ｍｍ、対極２３は直径１０ｍｍ、イオン交換膜７０（ナフィオン膜）は直径７ｍｍ、厚さ５０μｍ、第一保水部材４１、第二保水部材４２および第三保水部材４３はそれぞれ直径１０ｍｍとした。 [Example 1]
Examples of the present invention will be described.
The electrochemical sensor X of the present invention was configured as shown in FIG.
That is, in the electrochemical sensor X of this example, the reaction electrode 21 has a diameter of 5 mm, the reference electrode 22 has a diameter of 7 mm, the counter electrode 23 has a diameter of 10 mm, the ion-exchange membrane 70 (Nafion membrane) has a diameter of 7 mm, and a thickness of 50 μm. The water retaining member 41, the second water retaining member 42, and the third water retaining member 43 each had a diameter of 10 mm.

筐体１０および蓋部材１１は、通常の手法による超音波融着によって固定した。ガス導入部１１ａに設けた筒部材１４の長寸は２．５ｍｍとし、ピンホール１４ａの孔径は０．０７ｍｍとした。筒部材１４の表面にエポキシ系接着剤を塗布することによって、ガス導入部１１ａに接着した。   The casing 10 and the lid member 11 were fixed by ultrasonic fusion using a normal method. The long dimension of the cylindrical member 14 provided in the gas introduction part 11a was 2.5 mm, and the hole diameter of the pinhole 14a was 0.07 mm. An epoxy adhesive was applied to the surface of the cylindrical member 14 to adhere to the gas introducing portion 11a.

反応極２１は蓋部材１１に３２０℃で熱融着した。その後、反応極２１に対してナフィオン溶液を塗布し乾燥器で焼成した。参照極２２に対してもナフィオン溶液を塗布し乾燥器で焼成した。   The reaction electrode 21 was heat-sealed to the lid member 11 at 320 ° C. Thereafter, a Nafion solution was applied to the reaction electrode 21 and baked in a dryer. A Nafion solution was also applied to the reference electrode 22 and baked in a dryer.

対極２３およびガス透過膜５３の固定については、以下のようにして行った。即ち、ドーナツ型の土台となる樹脂製の内部部材１９を配設し、当該内部部材１９に対極２３およびガス透過膜５３を熱融着させた。当該熱融着は、３２０℃の温度で行った。その後、対極２３に対してナフィオン溶液を塗布し乾燥器で焼成した。   The counter electrode 23 and the gas permeable membrane 53 were fixed as follows. In other words, the resin internal member 19 serving as a donut-shaped base was disposed, and the counter electrode 23 and the gas permeable film 53 were thermally fused to the internal member 19. The heat fusion was performed at a temperature of 320 ° C. Thereafter, a Nafion solution was applied to the counter electrode 23 and baked with a drier.

内部部材１９の中心の開口部１９ａには筒部材１６を挿通させた。底面貫通孔１１ｂに設けた筒部材１６の長寸は３．５ｍｍとし、ピンホール１４ａの孔径は０．０５ｍｍとした。内部部材１９は、エポキシ系接着剤である接着剤９０によって筐体１０の底面１０ｃに接着した。また、接着剤９０を筒部材１６の表面に塗布して底面貫通孔１１ｂおよび開口部１９ａと接着した。   The cylindrical member 16 was inserted through the opening 19a at the center of the internal member 19. The long dimension of the cylindrical member 16 provided in the bottom through-hole 11b was 3.5 mm, and the hole diameter of the pinhole 14a was 0.05 mm. The internal member 19 was adhered to the bottom surface 10c of the housing 10 with an adhesive 90 that is an epoxy adhesive. Further, the adhesive 90 was applied to the surface of the cylindrical member 16 and adhered to the bottom through-hole 11b and the opening 19a.

三枚の保水部材４０には、０．１２ｍＬの硫酸（４２重量％）の電解液３１をそれぞれ保持させた。   Each of the three water retaining members 40 held 0.12 mL of an electrolytic solution 31 of sulfuric acid (42 wt%).

結露・圧力緩和膜８０（多孔質ＰＴＦＥ膜）は、ガス導入部１１ａおよび反応極２１の間、および、ガス導入部１１ａの雰囲気側（反応極２１の反対側）に配設した。さらに結露・圧力緩和膜８０はガス導入部１１ａに限らず、底面貫通孔１１ｂおよび対極２３の間に配設した。   The dew condensation / pressure relaxation membrane 80 (porous PTFE membrane) was disposed between the gas introduction part 11a and the reaction electrode 21 and on the atmosphere side of the gas introduction part 11a (opposite to the reaction electrode 21). Further, the dew condensation / pressure relaxation film 80 is disposed not only in the gas introduction part 11 a but also between the bottom through hole 11 b and the counter electrode 23.

ガス導入部１１ａにおける結露・圧力緩和膜８０の雰囲気側には活性炭繊維９１（クラレケミカル社製）を配設し、その外方にはセンサ内部に塵や埃などが侵入するのを防止する防塵フィルター９２（日本バルカー工業社製）を配設した。当該防塵フィルター９２は、底面貫通孔１１ｂの側にも配設した。   Activated carbon fiber 91 (manufactured by Kuraray Chemical Co., Ltd.) is disposed on the atmosphere side of the dew condensation / pressure relaxation film 80 in the gas introduction section 11a, and dust prevention to prevent dust and dirt from entering the sensor outside. A filter 92 (manufactured by Nippon Valqua Industries, Ltd.) was disposed. The dust filter 92 was also disposed on the bottom through hole 11b side.

〔実施例２〕
実施例１で作製した電気化学式センサＸを使用して、酸素ガスを検知した場合の応答速度を調べた。酸素ガス０ｖｏｌ％の被検知ガスおよび酸素ガス１５ｖｏｌ％の被検知ガスを検知した結果を図８に示した。 [Example 2]
Using the electrochemical sensor X produced in Example 1, the response speed when oxygen gas was detected was examined. FIG. 8 shows the result of detecting the gas to be detected with 0 vol% oxygen gas and the gas to be detected with 15 vol% oxygen gas.

測定開始後、酸素ガス０ｖｏｌ％の被検知ガスを１８０秒間検知させ、酸素ガス１５ｖｏｌ％の被検知ガスを３２０〜５００秒まで１８０秒間検知させたところ、それぞれの被検知ガスについて適切な酸素濃度の指示値を示すものと認められた。   After the start of measurement, the detected gas with 0 vol% oxygen gas was detected for 180 seconds, and the detected gas with 15 vol% oxygen gas was detected for 320 seconds from 320 to 500 seconds. The indicated value was recognized.

〔実施例３〕
実施例１で作製した電気化学式センサＸを使用して、酸素ガスを検知した場合の直線性を調べた。酸素ガス０，１０，１５，２１，２５ｖｏｌ％の被検知ガスをそれぞれ検知した結果を図９に示した。 Example 3
Using the electrochemical sensor X produced in Example 1, the linearity when oxygen gas was detected was examined. FIG. 9 shows the results of detecting the detected gases of oxygen gas 0, 10, 15, 21, and 25 vol%.

その結果、酸素濃度を種々変更した場合であっても指示値の直線性は維持されるものと認められた。
〔実施例４〕
実施例１で作製した電気化学式センサＸを使用して、酸素ガスを検知した場合の経時安定性を調べた。通電１日後からの指示値の変動を調べた結果を図１０に示した。 As a result, it was recognized that the linearity of the indicated value was maintained even when the oxygen concentration was variously changed.
Example 4
Using the electrochemical sensor X produced in Example 1, the stability over time when oxygen gas was detected was examined. FIG. 10 shows the result of examining the fluctuation of the indicated value after one day after energization.

その結果、通電後１２０日が経過した後であっても、通電当初からの指示値と同等の指示値を維持したため、経時安定性の優れた電気化学式センサであると認められた。   As a result, even after 120 days had passed since energization, the indicated value equivalent to the indicated value from the beginning of energization was maintained, so that it was recognized as an electrochemical sensor with excellent temporal stability.

本発明は、筐体の内部に、反応極と、参照極と、対極と、これら電極に接する電解液と、を備えた電気化学式センサに利用できる。   INDUSTRIAL APPLICABILITY The present invention can be used for an electrochemical sensor including a reaction electrode, a reference electrode, a counter electrode, and an electrolyte solution in contact with these electrodes inside a housing.

Ｘ 電気化学式センサ
１０ 筐体
１０ｃ 底面
１１ 蓋部材
１１ａ ガス導入部
１４ 筒部材
１４ａ ピンホール
１９ 内部部材
２０ ガス電極
２１ 反応極
２２ 参照極
２３ 対極
３１ 電解液
４０ 保水部材
７０ イオン交換膜
８０ 結露・圧力緩和膜 X Electrochemical sensor 10 Case 10c Bottom surface 11 Lid member 11a Gas introduction part 14 Cylindrical member 14a Pin hole 19 Internal member 20 Gas electrode 21 Reaction electrode 22 Reference electrode 23 Counter electrode 31 Electrolytic solution 40 Water retention member 70 Ion exchange membrane 80 Condensation / pressure Relaxation film

Claims (5)

筐体の内部に、ガスを検知するガス電極として被検知ガスを電気化学反応させる反応極と、参照極と、対極と、をこの順に収容し、これらガス電極は、それぞれ電解液を吸水して保持する保水部材を介して積層してある電気化学式センサ。   A reaction electrode for electrochemically reacting a gas to be detected as a gas electrode for detecting a gas, a reference electrode, and a counter electrode are accommodated in this order in the housing, and each of these gas electrodes absorbs an electrolyte solution. An electrochemical sensor laminated through a water retaining member to be held. 前記反応極および前記対極の間にイオン交換膜を配設した請求項１に記載の電気化学式センサ。   The electrochemical sensor according to claim 1, wherein an ion exchange membrane is disposed between the reaction electrode and the counter electrode. 前記筐体を封止する蓋部材を備え、当該蓋部材に前記反応極を熱融着し、前記筐体の内部に設けた内部部材に前記対極を熱融着してある請求項１または２に記載の電気化学式センサ。   A lid member for sealing the casing is provided, the reaction electrode is thermally fused to the lid member, and the counter electrode is thermally fused to an internal member provided in the casing. The electrochemical sensor according to 1. 当該蓋部材および前記筐体の底面のそれぞれにピンホールを形成した筒部材を配設してある請求項３に記載の電気化学式センサ。   The electrochemical sensor according to claim 3, wherein a cylindrical member in which a pinhole is formed is provided on each of the lid member and the bottom surface of the casing. 前記蓋部材におけるガス導入部および前記反応極の間に結露・圧力緩和膜が配設してある請求項４に記載の電気化学式センサ。
5. The electrochemical sensor according to claim 4, wherein a dew condensation / pressure relaxation film is disposed between the gas introduction part and the reaction electrode in the lid member.
JP2016048459A 2016-03-11 2016-03-11 Electrochemical sensor Pending JP2017161457A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018048972A (en) * 2016-09-23 2018-03-29 新コスモス電機株式会社 Constant potential electrolytic gas sensor and manufacturing method therefor
CN108680617A (en) * 2018-03-26 2018-10-19 深圳市普晟传感技术有限公司 A kind of hydrogen gas sensor
JP2020139818A (en) * 2019-02-27 2020-09-03 国立大学法人 筑波大学 Oxygen electrode and measuring device

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018048972A (en) * 2016-09-23 2018-03-29 新コスモス電機株式会社 Constant potential electrolytic gas sensor and manufacturing method therefor
CN108680617A (en) * 2018-03-26 2018-10-19 深圳市普晟传感技术有限公司 A kind of hydrogen gas sensor
CN108680617B (en) * 2018-03-26 2021-01-26 深圳市普晟传感技术有限公司 Hydrogen sensor
JP2020139818A (en) * 2019-02-27 2020-09-03 国立大学法人 筑波大学 Oxygen electrode and measuring device
JP7229520B2 (en) 2019-02-27 2023-02-28 国立大学法人 筑波大学 Oxygen electrode and measuring device
JP2023053065A (en) * 2019-02-27 2023-04-12 国立大学法人 筑波大学 Oxygen electrode, measurement device, and method for manufacturing oxygen electrode
JP7464315B2 (en) 2019-02-27 2024-04-09 国立大学法人 筑波大学 Oxygen electrode, measuring device, and method for manufacturing oxygen electrode

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