JP4137630B2 - Constant-potential electrolysis gas sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a constant potential electrolytic gas sensor, and more particularly to a constant potential electrolytic gas sensor configured by separating a gas-permeable hydrophobic diaphragm and a working electrode.
[0002]
[Prior art]
At present, for example, when detecting a toxic gas in a semiconductor manufacturing factory, the gas concentration can be detected with high sensitivity and high accuracy with excellent selectivity of the target gas to be detected. A constant potential electrolysis gas sensor using an electrolytic reaction is widely used.
[0003]
Many such constant-potential electrolytic gas sensors have been proposed. For example, Patent Document 1 has, for example, a gas permeation port, and the gas permeation port is sealed with a gas permeable diaphragm. A counter electrode comprising a casing forming an electrolyte chamber, in which a plate-like working electrode is disposed in contact with the liquid-contacting surface of the diaphragm and a metal wire is wound in a coil shape And the reference electrode immersed in the electrolyte, and the lead members connected to the working electrode, the counter electrode, and the reference electrode are led out of the casing at different positions. Things have been proposed.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 07-055764
[Problems to be solved by the invention]
However, in the constant potential electrolytic gas sensor having the above-described configuration, it is necessary to form an opening for leading the lead member related to each electrode to the outside of the casing. There is a problem that it is difficult to form a highly reliable liquid-tight structure, and there is a possibility that target gas detection may not be performed reliably.
[0006]
The present invention has been made based on the above circumstances, and its purpose is to reliably prevent leakage of the electrolyte from the lead portion of the electrode required for gas detection. Another object of the present invention is to provide a small constant potential electrolytic gas sensor having a high liquid-tight structure.
[0007]
[Means for Solving the Problems]
The constant potential electrolytic gas sensor of the present invention includes a casing having a gas permeation port at one end, and the gas permeation port is sealed with a gas-permeable hydrophobic diaphragm to form an electrolyte chamber. An electrode structure in which at least the working electrode and the counter electrode are stacked via an electrolyte holding member impregnated with the electrolyte is in a state where the working electrode is in contact with the liquid-contacting surface of the gas-permeable hydrophobic diaphragm. A plurality of external lead members connected to each of the working electrode and the counter electrode are arranged on the outer surface of the casing so as to extend in the stacking direction of the electrodes;
Each of the working electrode and the counter electrode is composed of a plate-shaped electrode body and a protruding terminal piece for connecting the electrode body and the external lead member,
Each of the projecting terminal pieces in the working electrode and the counter electrode is led out of the casing at a position spaced apart from each other in the circumferential direction ,
The working electrode and the counter electrode are each an electrode body part forming an electrode body, and a base end part extending in a different protruding direction and a tip end part extending in parallel with each other in a state where the electrode body parts are stacked The electrode-forming material having the terminal piece portion is bent so that the proximal end portion of the protruding terminal piece portion extends in the stacking direction of the electrode body and the distal end side portion of the protruding terminal piece portion extends in the surface direction of the electrode body. Further, a portion protruding from the outer surface of the casing is formed to be bent so as to extend in the stacking direction of the electrode body .
[0009]
[Action]
According to the constant potential electrolytic gas sensor having the above configuration, basically, at least both the working electrode and the counter electrode are stacked via the electrolyte solution holding member and configured as one electrode structure. Since a plurality of necessary electrodes are collected, the size of the space occupied by the gas detection electrode in the entire gas sensor is reduced, and the gas sensor itself is greatly reduced in size.
In addition, each of the protruding terminal pieces in the working electrode and the counter electrode is configured to be led out of the casing at a position spaced apart in the circumferential direction, thereby ensuring high liquid tightness in the electrolyte chamber. Therefore, it is possible to reliably prevent the electrolytic solution from leaking.
[0010]
Since the protruding terminal piece related to the working electrode and the protruding terminal piece related to the counter electrode have a specific form, the liquid-tight lead structure in which the protruding terminal pieces related to each electrode are led out in the same direction can be simplified. It can be reliably obtained by the structure.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing an outline of the configuration of an example of a constant potential electrolytic gas sensor of the present invention, FIG. 2 is a side view of the constant potential electrolytic gas sensor shown in FIG. 1, and FIG. FIG. 4 is an enlarged cross-sectional view of the electrode structure in the constant-potential electrolysis gas sensor shown in FIG. In this specification, the vertical direction in FIG. 1 is referred to as an “axial direction”, and the horizontal direction is referred to as a “radial direction”.
[0012]
This constant potential electrolytic gas sensor includes a casing 10 constituted by a cylindrical casing body 10A, a lower casing member 10B and an upper casing member 10C, and a plurality of required gas detection electrodes, in this embodiment The electrode structure 30 in which the working electrode 31, the counter electrode 32, and the reference electrode 33 are configured as one unit is fitted into the opening on one end side of the casing body 10A so that the working electrode 31 is exposed to the outer surface. Further, the electrode structure 30 is fitted into the electrode structure fitting recess 14 formed on the other end surface of the lower casing member 10B in which the gas permeation port 11 is formed so as to come into contact with the casing body 10A. The upper casing member 10C is provided by being fitted into the other end opening of the casing body 10A. It is.
In the electrode structure fitting recess 14 in the lower casing member 10B, a step 14A in which a seal member such as an O-ring 18A is disposed is formed, and on the inner surface thereof, for example, polytetrafluoro A gas permeable hydrophobic diaphragm 20 made of a fluororesin such as ethylene (PTFE) is disposed so as to block the gas permeable port 11 and is integrally welded. As a result, the electrolyte chamber S in which the electrolyte is accommodated is liquid. It is densely formed.
The gas permeable hydrophobic diaphragm 20 is in contact with the working electrode 31.
[0013]
The casing 10 has an input / output terminal to which each of the external lead members 25, 25, 25 corresponding to each of the gas detection electrodes is connected to a joint portion of the casing main body 10A and the lower casing member 10B on the outer peripheral surface thereof. The portion forming recesses 12 are formed, and are arranged at a distance from each other in the circumferential direction so as to extend outward in the axial direction (upward in FIG. 1) from the input / output terminal portion forming recesses 12. A plurality of outer lead member disposing guide grooves 13 are formed. In FIGS. 1 and 3, reference numeral 19 denotes an electrolytic solution injection through hole for injecting the electrolytic solution into the electrolytic solution chamber S.
[0014]
The upper surface side casing member 10 </ b> C has an electrolyte chamber overpressure adjustment function for maintaining the internal space of the electrolyte chamber S in a state of being balanced with the pressure of the external atmosphere.
Specifically, on the inner surface exposed to the internal space of the electrolyte chamber S, a first space portion 15A having a constant opening diameter, and an axially outward (see FIG. A concave portion 15 having a second space portion 15B having a smaller opening diameter as it goes upward (in FIG. 5B) and a tapered inner wall surface forming the second space portion 15B in the concave portion 15. A communication hole 16 extending radially outward is formed so as to open on the outer peripheral surface of the upper casing member 10C, and a gas permeable pressure made of, for example, polytetrafluoroethylene (PTFE) is formed on the inner surface of the upper casing member 10C. The adjustment film 21 is disposed and integrally welded, so that the internal space of the electrolyte chamber S is released to the outside atmosphere in a state where a liquid-tight state is ensured.
[0015]
Each of the working electrode 31, the counter electrode 32, and the reference electrode 33 is a disk-shaped electrode body 31A, 32A, 33A, and the whole protrudes radially outward from the periphery of the electrode bodies 31A, 32A, 33A. Each of the electrode bodies 31A, 32A, and 33A related to each electrode has a fluid flow path, for example, an opening diameter of 0.5 mm is formed by protruding terminal pieces 31B, 32B, and 33B formed to extend. The fine through-holes 34 are formed at a constant pitch at a density of 80 holes / cm ² (see FIGS. 5 to 7).
[0016]
As shown in FIG. 5, the working electrode 31 has a protruding terminal piece portion 41 that extends, for example, linearly outward from the peripheral edge of the disc-shaped electrode body 31A, for example, from stainless steel. The working electrode forming material 40 is formed by attaching gold to the surface of the substrate.
Specifically, at the bent portion indicated by a broken line A where the protruding terminal piece portion 41 of the working electrode forming material 40 is positioned at one end thereof, the base end side portion 41A is perpendicular to the paper surface (outside in the axial direction). The tip end portion 41B is bent so as to extend downward (radially outward) in the drawing at a bent portion indicated by a broken line B, and further indicated by a broken line C. The contact terminal portion 41C is bent so as to extend in the direction perpendicular to the paper surface (inward in the axial direction) at the portion to be bent, whereby a protruding terminal piece having a rectangular cross section as shown in FIG. A working electrode 31 having 31B is formed.
[0017]
In the state where the electrode body 32A is coaxially stacked with the electrode body 31A related to the working electrode forming material 40 as shown in FIG. The protruding terminal piece portion 41 according to the present invention protrudes and extends in a direction different from the protruding direction, in other words, a peripheral edge having a predetermined phase angle difference with respect to the protruding direction of the protruding terminal piece portion 41 according to the working electrode forming material 40. The tip side portion 43B having the contact terminal portion 43C at the tip extends and extends in parallel with the protruding direction of the protruding terminal piece portion 41 of the working electrode forming material 40. It is formed of a counter electrode forming material 42 that has a protruding terminal piece portion 43 that is bent in a U-shape, and is made of, for example, silver adhered to the surface of a base material made of stainless steel.
Specifically, at the bent portion indicated by the broken line A where the protruding terminal piece portion 43 of the counter electrode forming material 42 is positioned at one end thereof, the base end side portion 43A is perpendicular to the paper surface (the axially outward side). ), The distal end portion 43B is bent so as to extend downward (radially outward) in the drawing at the bent portion indicated by the broken line B, and further, the bent portion indicated by the broken line C The contact terminal forming portion 43C is bent so as to extend toward the back side in the vertical direction (inward in the axial direction) with respect to the paper surface at the bent portion, and has the same rectangular shape as that related to the working electrode 31 as shown in FIG. The counter electrode 32 having the protruding terminal piece 32B having the cross-sectional shape is formed.
[0018]
The reference electrode 33 is, for example, in a state where the electrode body 33A is coaxially stacked with the electrode bodies 31A and 32A according to each of the working electrode forming material 40 and the counter electrode forming material 42 as shown in FIG. The projecting terminal piece portion 41 according to the working electrode forming material 40 is substantially symmetrical with the projecting terminal piece portion 43 according to the counter electrode forming material 42, and is bent in the shape of a "<". It is formed of a reference electrode forming material 44 having silver protrudingly attached to the surface of a base material made of stainless steel, for example, having protruding terminal piece portions 45.
Specifically, at the bent portion indicated by the broken line A located at one end of the protruding terminal piece portion 45 in the reference electrode forming material 44, the base end side portion 45A is perpendicular to the paper surface (the axially outward side). ), The tip side portion 45B is bent so as to extend downward (in the radial direction) in the drawing at the bent portion indicated by the broken line B, and further, the bent portion indicated by the broken line C. The protruding terminal piece 33B having a rectangular cross-sectional shape as shown in FIG. 3 is bent at the bent portion so that the contact terminal portion 45C extends toward the back side in the vertical direction (inward in the axial direction). A reference electrode 33 is formed.
[0019]
As described above, in the constant potential electrolytic gas sensor of the present invention, the working electrode 31, the counter electrode 32, and the reference electrode 33 are configured as one electrode structure 30.
In this embodiment, one end side has a large-diameter cylindrical portion 36A to be fitted into the electrode structure fitting recess 14 in the lower casing member 10B, and the other end side has a sealing member such as a ring-shaped packing 18B. With a small-diameter cylindrical portion 36B fitted to the opening on the one end side of the casing body 10A, with an electrode body disposing through-hole 37 extending in the axial direction and a small-diameter cylindrical shape. The working electrode 31, the counter electrode 32, and the reference electrode 33 are held by the electrode holder 36 in which the protruding terminal piece disposition cutout portion 38 extending in the axial direction is formed on the wall surface of the portion 36 </ b> B at a position spaced apart from each other in the circumferential direction. Thus, it is configured as one unit.
[0020]
Specifically, as shown in FIG. 4, an electrode body 31 </ b> A related to each gas detection electrode of the working electrode 31, the counter electrode 32, and the reference electrode 33 in the through hole 37 for arranging the electrode body in the electrode holder 36. 32A and 33A are made of filter paper, for example, between the electrode body 31A related to the working electrode 31 and the electrode body 32A related to the counter electrode 32, and between the electrode body 32A related to the counter electrode 32 and the electrode body 33A related to the reference electrode 33. The sheet-like electrolyte solution holding members 35A and 35B are interposed and disposed in a state of being stacked in this order with respect to the permeation direction of the test gas (from the bottom to the top in FIG. 4). The protruding terminal piece arrangement surface 3 in the large-diameter cylindrical portion 36A is inserted through the protruding terminal piece arrangement cutout portions 38 corresponding to the protruding terminal pieces 31B, 32B, 33B related to the gas detection electrodes. Further, in the state where the electrolyte solution holding member 35C is disposed on the electrode body 33A related to the reference electrode 33, the protective plate 50 has a small-diameter cylindrical portion 51 whose electrode body is disposed therethrough. The large-diameter cylindrical portion 52 is fitted into the hole 37 and is fitted into a protective plate fitting recess 36 </ b> C formed on the inner surface exposed to the internal space of the electrolyte chamber S of the small-diameter cylindrical portion 36 </ b> B in the electrode holder 36. In addition, they are integrally provided in a state where they are pressed or in close contact with the electrolyte solution holding member 35C located in the uppermost layer.
[0021]
Each of the protruding terminal pieces 31B, 32B, 33B in each gas detection electrode has a through hole 37 for arranging the electrode body in the electrode holder 36 at a position where the base end portions 41A, 43A, 45A are spaced apart from each other in the circumferential direction. The tip end portions 41B, 43B, 45B extend radially outward along the protruding terminal piece arrangement surface 39 of the electrode holder 36 along the inner wall surface, and input / output terminal portions of the casing 10 The contact terminal portions 41C, 43C, 45C led out in the circumferential direction in the forming recess 12 extend inward in the axial direction along the wall surface of the input / output terminal portion forming recess 12. ing.
[0022]
For example, the protective plate 50 constituting the electrode structure 30 has, for example, 40 through-holes 53 with an opening diameter of about 1 mm, which are fluid flow paths through which the introduced test gas flows and the electrolyte solution flows. It is formed to extend in the axial direction at a density of / cm ² .
[0023]
Each of the external lead members 25 is composed of a pin lead in which one end side portion 25A located in the input / output terminal portion forming recess 12 is formed in a semicircular cross section, and a flat surface in the one end side portion 25A is an outer surface. In the state of facing in the direction (right side in FIG. 1), each of the protruding terminal pieces 31B, 32B, 33B related to the corresponding gas detection electrode is connected to the tip portion.
The input / output terminal portion forming recess 12 in the casing 10 is covered with an insulating resin layer 17 for liquid-tight sealing, thereby forming a liquid-tight sealing structure.
[0024]
In the above, examples of the electrolytic solution used in the constant potential electrolytic gas sensor of the present invention include 0.25 mol potassium iodide (KI), 0.05 mol potassium iodate (KIO ₃ ), and potassium hydroxide 0. 0.5 mmol aqueous solution as a basic composition, and a hydrogen ion concentration adjusting agent, specifically, for example, potassium hydroxide or potassium carbonate is added to adjust the hydrogen ion concentration so that it is more alkaline than neutral. It is configured.
[0025]
The type of detection target gas is not particularly limited, for example, hydrogen fluoride gas (HF), hydrogen chloride gas (HCl), chlorine gas (Cl _2), fluorine gas (F _2), iodine gas (I ₂ ), bromine gas (Br ₂ ), ozone gas (O ₃ ), chlorine fluoride gas (ClF ₃ ) and the like.
[0026]
In the above, the constant potential electrolytic gas sensor of the present invention is used in a state where the gas permeation port 11 is directed in a direction other than the upward direction, for example, in the lateral direction, whereby the electrolytic solution accommodated in the electrolytic solution chamber S is It flows into the through hole 53 in the protection plate 50 and is impregnated in the electrolyte solution holding member 35C interposed between the protection plate 50 and the reference electrode 33. Further, the excess electrolyte solution passes through the through hole 34 and the reference electrode 33. The electrolyte solution holding members 35B and 35A that sequentially enter the through-hole 34 of the counter electrode 32 and are interposed between the electrodes are impregnated, and electrolysis is performed between the working electrode 31 and the gas-permeable hydrophobic diaphragm 20. A liquid layer is formed, whereby a liquid-tight state is obtained between the electrodes.
In this state, for example, a test gas such as air in an ambient atmosphere is introduced from the gas permeation port 11 through the gas permeable hydrophobic diaphragm 20, and a certain potential difference is generated between the working electrode 31 and the counter electrode 32. Based on the potential state of the reference electrode 33, a predetermined voltage is applied to each of the working electrode 31 and the counter electrode 32 via the external lead members 25, 25, 25, and is generated between both the working electrode 31 and the counter electrode 32. By measuring the current value, the concentration of the specific component (detection target gas) in the test gas is detected.
The test gas introduced into the electrolyte chamber S passes through the gas permeable pressure adjusting membrane 21 and is discharged from the communication hole 16 through the recess 15 to the outside atmosphere. Is adjusted to a pressure state balanced with the pressure of the external atmosphere, and the gas detection operation is performed.
[0027]
Thus, according to the constant potential electrolytic gas sensor having the above configuration, basically, the working electrode 31, the counter electrode 32, and the reference electrode 33 are stacked through the electrolyte solution holding members 35 and 35. By being configured as one electrode structure 30, a plurality of required electrodes are gathered, so that the size of the occupied space of the electrode in the entire gas sensor can be reduced. The sensor itself can be configured as being significantly miniaturized.
As a specific dimension example, the axial length of the casing can be set to 30 mm, for example, and the outer diameter can be set to 20 mm, for example.
[0028]
In addition, each of the protruding terminal pieces 31A, 32A, 33A related to the gas detection electrodes of the working electrode 31, the counter electrode 32, and the reference electrode 33 is led out of the casing 10 at positions spaced apart in the circumferential direction. As a result, the electrolytic solution chamber S can be configured in a state in which high liquid tightness is ensured, so that it is possible to reliably prevent the electrolytic solution from leaking.
Further, since the external lead members 25, 25, 25 corresponding to the working electrode 31, the counter electrode 32, and the reference electrode 33 are arranged close to each other, it is extremely advantageous when forming a current supply structure.
[0029]
Further, the electrolytic solution holding member 35C is used in a state where the gas permeation port 11 faces in a direction other than the upward direction, and the electrolytic solution is passed through the through hole 53 in the protective plate 50 and the through hole 34 formed in each electrode. This is a case where the electrolyte solution is reduced to a small amount by impregnating each of 35B and 35A and forming an electrolyte solution layer between the working electrode 31 and the gas permeable hydrophobic diaphragm 20. However, since the electrolyte solution can be reliably supplied to the respective electrolyte solution holding members 35C, 35B, 35A and the gaps between the working electrode 31 and the gas-permeable hydrophobic diaphragm 20, a sufficiently liquid-tight state is provided between the electrodes. Can be definitely obtained.
Therefore, for example, even if the posture of the gas sensor tilts due to being carried by a person, a sufficiently liquid-tight state can be obtained between the electrodes, and the reliability is high. Gas detection can be performed reliably.
[0030]
Furthermore, the laminated body of the electrode bodies 31A, 32A, 33A and the electrolyte solution holding members 35A, 35B, 35C according to each electrode is held by the electrode holder 36 in a state of being pressed or intimately contacted by the protective plate 50. Accordingly, the electrolyte solution holding members 35A, 35B, and 35C can be reliably prevented from being deformed as the electrolyte solution is impregnated and swollen, so that a substantially uniform liquid-tight state between the electrodes can be obtained. The target gas detection can be reliably performed.
[0031]
Further, the casing structural member, the electrode structure 30 and other structural members are assembled, that is, in a state where the electrode structure 30 is exposed to the outer surface at the one end side opening of the casing body 10A. In this state, the lower casing member 10B, in which the gas permeable hydrophobic diaphragm 20 is integrally provided on the inner surface, is provided in a state where the electrode structure 30 is fitted, and the casing body. The upper casing member 10C is provided by being fitted to the other end opening of 10A, and the external lead members 25, 25, 25 are disposed on the outer peripheral surface of the casing 10, and the protruding terminals of the corresponding gas detection electrodes Since each of the pieces 31B, 32B, and 33B is connected and configured, it is very easy to manufacture a constant potential electrolytic gas sensor having desired characteristics. It can be.
[0032]
As mentioned above, although embodiment of this invention was described, this invention is not limited to said aspect, A various change can be added.
For example, in the constant-potential electrolysis gas sensor according to the present invention, it is not essential that the reference electrode is provided, and it is only necessary that the gas detection electrode is constituted by at least the working electrode and the counter electrode.
[0033]
Further, in the constant potential electrolytic gas sensor according to the present invention, the fluid flow path according to each electrode is formed so that the electrolytic solution is substantially uniformly impregnated in the surface direction of the electrolytic solution holding member. For example, the size of the opening diameter, the formation density, the formation pattern, and other configurations can be appropriately changed, and for example, a notch shape may be used.
Furthermore, the counter electrode and the reference electrode are not limited to the configuration in which the through-hole is formed over the entire surface of the electrode body as long as a fluid flow path (liquid conduction path) is secured. It may be a thing.
In addition, the electrolyte chamber does not need to be filled in the electrolyte chamber, and only the amount required to obtain a sufficient liquid-tight state between the electrodes is taken into account in consideration of the decrease in the electrolyte due to evaporation and the like. What is necessary is just to be accommodated in the liquid chamber.
[0034]
【The invention's effect】
According to the constant potential electrolytic gas sensor of the present invention, basically, at least both the working electrode and the counter electrode are stacked via the electrolyte holding member and configured as one electrode structure. Since a plurality of required gas detection electrodes are collected, the size of the space occupied by the gas detection electrodes in the entire gas sensor is reduced, and the gas sensor itself is greatly reduced in size.
In addition, each of the protruding terminal pieces of the working electrode and the counter electrode protrudes in the same direction and extends to the outside of the casing at positions spaced apart from each other in the circumferential direction, thereby making the electrolyte chamber highly liquid-tight. Therefore, it is possible to reliably prevent the electrolyte from leaking.
[0035]
Further, since the protruding terminal piece related to the working electrode and the protruding terminal piece related to the counter electrode have a specific form, the protruding terminal pieces related to each electrode of the working electrode and the counter electrode are led out in the same direction. A liquid-tight lead structure can be reliably obtained with a simple structure.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an outline of a configuration in an example of a constant potential electrolytic gas sensor of the present invention.
FIG. 2 is a side view of the constant potential electrolytic gas sensor shown in FIG.
FIG. 3 is an exploded cross-sectional view of the constant potential electrolytic gas sensor shown in FIG.
4 is an enlarged cross-sectional view showing a configuration of an electrode structure in the constant potential electrolytic gas sensor shown in FIG. 1. FIG.
FIG. 5 is a plan view showing a configuration of a working electrode forming material.
FIG. 6 is a plan view showing a configuration of a counter electrode forming material.
FIG. 7 is a plan view showing a configuration of a reference electrode forming material.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Casing 10A Casing main body 10B Lower surface side casing member 10C Upper surface side casing member 11 Gas permeation | transmission port 12 Input / output terminal part formation recess 13 External lead member arrangement guide groove 14 Electrode structure fitting recess 14A Step part 15 Recess 15A 1st space part 15B 2nd space part 16 Communication hole 17 Insulating resin layer 18A O-ring 18B Ring-shaped packing 19 Through-hole 20 for electrolyte injection Gas-permeable hydrophobic diaphragm 21 Gas-permeable pressure adjusting film 25 External lead member 25A One end portion S Electrolyte chamber 30 Electrode structure 31 Working electrode 32 Counter electrode 33 Reference electrode 31A, 32A, 33A Electrode body 31B, 32B, 33B Projecting terminal piece 34 Through hole 35A, 35B, 35C Electrolyte holding member 36 Electrode holder 36A Large-diameter cylindrical portion 36B Small-diameter cylindrical portion 36C Protection plate fitting recess 37 Electrode arrangement Through hole 38 Protruding terminal piece notch 39 Protruding terminal piece disposing surface 40 Working electrode forming material 42 Counter electrode forming material 44 Reference electrode forming material 41, 43, 45 Protruding terminal piece portions 41A, 43A, 45A Base side Part 41B, 43B, 45B Tip side part 41C, 43C, 45C Contact terminal part 50 Protection plate 51 Small diameter cylindrical part 52 Large diameter cylindrical part 53 Through-hole

Claims (1)

A casing having a gas permeable port at one end and sealed with a gas permeable hydrophobic diaphragm to form an electrolytic solution chamber, and in this casing, at least the working electrode and the counter electrode are impregnated with the electrolytic solution. The electrode structure formed by stacking the electrolyte holding members is disposed in a state where the working electrode is in contact with the liquid-contacting surface of the gas-permeable hydrophobic diaphragm, and on the outer surface of the casing, the working electrode and A plurality of external lead members connected to each of the counter electrodes are arranged to extend in the stacking direction of the electrodes,
Each of the working electrode and the counter electrode is composed of a plate-shaped electrode body and a protruding terminal piece for connecting the electrode body and the external lead member,
Each of the projecting terminal pieces in the working electrode and the counter electrode is led out of the casing at a position spaced apart from each other in the circumferential direction ,
The working electrode and the counter electrode are each an electrode body part forming an electrode body, and a base end part extending in a different protruding direction and a tip end part extending in parallel with each other in a state where the electrode body parts are stacked The electrode-forming material having the terminal piece portion is bent so that the proximal end portion of the protruding terminal piece portion extends in the stacking direction of the electrode body and the distal end side portion of the protruding terminal piece portion extends in the surface direction of the electrode body. And a portion protruding from the outer surface of the casing is bent so as to extend in the stacking direction of the electrode body .

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