JP4101641B2 - 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]
In such a constant potential electrolytic gas sensor, it is necessary that a plurality of electrodes required for the gas detection operation are in a conductive state (liquid-tight state) through the electrolyte.
Thus, the electrolyte solution evaporates due to environmental conditions such as temperature and humidity and the amount thereof decreases, and it may be difficult to operate normally while maintaining the conductive state between the electrodes.
[0004]
For such a problem, for example, in Japanese Patent Laid-Open No. 6-229980 of Patent Document 1, a plate-like material is formed on one surface side through a porous material having a water permeability partly immersed in an electrolytic solution. A working electrode is disposed in contact with each other, and a plate-shaped counter electrode and a plate-shaped reference electrode are disposed in contact with each other on the other side, whereby each electrode is interposed via a porous material impregnated with an electrolytic solution. A constant-potential electrolysis gas sensor having a configuration in which the gap is liquid-tight is described.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 06-229980
[0006]
[Problems to be solved by the invention]
As described above, in the constant potential electrolysis gas sensor, a plurality of required gas detection electrodes are required to be in a liquid-tight state.
Accordingly, an object of the present invention is to provide a small-sized constant potential electrolytic gas sensor having a novel configuration capable of bringing a plurality of required gas detection electrodes into a sufficiently liquid-tight state. .
[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, the gas permeation port being sealed by a gas permeable hydrophobic diaphragm, and forming an electrolyte chamber in which an electrolytic solution is accommodated. In this casing, at least two gas detection electrodes, that is, a working electrode and a counter electrode, are disposed in a state where the working electrode is in contact with the gas-permeable hydrophobic diaphragm and the counter electrode is liquid-tight with respect to the working electrode. In the constant potential electrolytic gas sensor
The working electrode and counter electrode are both Consists of a through-hole through which the test gas introduced through the gas-permeable hydrophobic diaphragm from the electrolyte solution and the gas permeation port in the electrolyte chamber. It has a plate-like electrode body in which a fluid flow path is formed, and both the working electrode and the counter electrode have an electrolyte solution holding member interposed between the electrode body related to the working electrode and the electrode body related to the counter electrode. It is characterized by being stacked as a sandwiched state and configured as one electrode structure.
[0008]
In the constant potential electrolytic gas sensor of the present invention, the gas permeation is performed so that the electrolytic solution accommodated in the electrolytic solution chamber is impregnated in the electrolytic solution holding member through the fluid flow passage formed in each of the working electrode and the counter electrode. It is preferably used in a state where the mouth faces a direction other than the upward direction.
In the constant potential electrolytic gas sensor of the present invention, the gas detection is performed at a position where a plurality of external lead members corresponding to each of the gas detection electrodes are arranged apart from each other in the circumferential direction on the outer peripheral surface of the casing. It is preferable that the electrodes are arranged to extend in the stacking direction of the electrodes.
Furthermore, in the constant potential electrolytic gas sensor of the present invention, Consists of a through-hole through which the test gas introduced through the gas-permeable hydrophobic diaphragm from the electrolyte solution and the gas permeation port in the electrolyte chamber. Comprising a reference electrode having a plate-like electrode body in which a fluid flow passage is formed;
The electrode structure is composed of a working electrode, a counter electrode, and a reference electrode between the electrode body related to the working electrode and the electrode body related to the counter electrode, and between the electrode body related to the counter electrode and the electrode body related to the reference electrode. It can be configured to be laminated with the electrolyte solution holding member interposed therebetween.
[0009]
[Action]
According to the constant potential electrolytic gas sensor having the above-described configuration, at least both the working electrode and the counter electrode are stacked via the electrolyte solution holding member to be configured as one electrode structure, and thus a plurality of required electrodes are provided. Therefore, 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.
[0010]
Further, the gas permeation port is used in a direction other than the upward direction, and the electrolytic solution holding member is impregnated with the electrolytic solution holding fluid through the fluid flow passages formed in the working electrode and the counter electrode. Since the electrolyte layer is formed between the gas permeable hydrophobic diaphragm, the electrolyte can be reliably supplied even when the electrolyte is reduced to a small amount. A sufficient liquid-tight state can be reliably obtained between the working electrode and the counter electrode.
Furthermore, since a plurality of external lead members corresponding to each of the plurality of required gas detection electrodes are arranged close to each other, it is extremely advantageous when forming a current supply 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. The protruding terminal pieces 31B, 32B, and 33B are formed to extend. The fine through holes 34 of about 80 density / cm ² In such a state, the holes are drilled at a constant pitch (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 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. 9, and in the state where the electrolyte solution holding member 35 </ b> C is disposed on the electrode body 33 </ b> A related to the reference electrode 33, the protective plate 50 has a small-diameter cylindrical portion 51 for disposing the electrode body. The large-diameter cylindrical portion 52 is fitted into the through-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. It is integrally provided in a state where it is 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. / Cm ² It is formed to extend in the axial direction at a density of.
[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 of potassium iodide (KI) and potassium iodate (KIO). _Three ) An aqueous solution of 0.05 mol and 0.5 mmol of potassium hydroxide has a basic composition, and a hydrogen ion concentration adjusting agent, specifically, for example, potassium hydroxide or potassium carbonate is added to the alkali side from neutrality. Thus, the hydrogen ion concentration is adjusted so that
[0025]
Moreover, the kind of detection object gas is not specifically 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 _Three ), Chlorine fluoride gas (ClF) _Three ) 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-described configuration, the working electrode 31, the counter electrode 32, and the reference electrode 33 are stacked through the electrolyte solution holding members 35A and 35B to form one electrode structure. Since the plurality of required gas detection electrodes are collected by being configured as 30, the size of the space occupied by the gas detection electrodes in the entire gas sensor can be reduced. As such, it can be configured as being significantly miniaturized.
As a specific dimension example, the axial length of the casing 10 can be set to 30 mm, for example, and the outer diameter can be set to 20 mm, for example.
[0028]
In addition, the electrolytic solution holding member 35C, 35B, 35A is used in a state where the gas permeation port 11 faces downward, and the electrolytic solution passes through the through hole 53 in the protective plate 50 and the through hole 34 formed in each electrode. Even if the electrolyte solution is reduced to a small amount by impregnating each of them and forming an electrolyte solution layer between the working electrode 31 and the gas permeable hydrophobic diaphragm 20, electrolysis is performed. Since the liquid can be reliably supplied to each electrolyte solution holding member 35C, 35B, 35A and the gap between the working electrode 31 and the gas permeable hydrophobic diaphragm 20, a sufficiently liquid-tight state can be reliably obtained between the electrodes. be able to.
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.
[0029]
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.
[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.
In addition, the fluid flow passages associated with each electrode, for example, if the electrolyte is formed so as to be substantially uniformly impregnated in the surface direction of the electrolyte holding member, for example, the size of the opening diameter, the formation density, the formation pattern, and Other configurations can be changed as appropriate, and may be, for example, notched.
Furthermore, it is not necessary for the electrolyte chamber to be filled in the electrolyte chamber, and only the amount required to obtain a sufficient liquid-tight state between the electrodes after taking into account the amount of decrease in the electrolyte due to evaporation or the like. What is necessary is just to be accommodated in the liquid chamber.
Further, 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 the fluid flow path (liquid conduction path) is secured. It may be a thing.
[0033]
【The invention's effect】
According to the constant potential electrolytic gas sensor of the present invention, at least both the working electrode and the counter electrode are stacked via the electrolyte solution holding member and configured as one electrode structure, and thus a plurality of required electrodes are provided. Since the gas detection electrodes of the gas sensor are combined, the space occupied by the gas detection electrode in the entire gas sensor can be reduced, and the gas sensor itself can be configured to be greatly downsized. .
[0034]
Also, the gas permeation port is used in a direction other than the upward direction, and the electrolytic solution holding member is impregnated through the fluid flow passage formed in the counter electrode, so Even when the liquid is reduced to a small amount, the electrolyte can be reliably supplied, so that a sufficiently liquid-tight state can be obtained between the working electrode and the counter electrode. Gas detection can be reliably performed with high reliability.
[0035]
Furthermore, since a plurality of external lead members corresponding to each of the plurality of required gas detection electrodes are arranged close to each other, it is extremely advantageous when forming a current supply 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]
10 Casing
10A casing body
10B Lower casing member
10C Upper surface side casing member
11 Gas permeation port
12 I / O terminal forming recess
13 Guide groove for disposing external lead member
14 Recess for electrode structure fitting
14A Step
15 recess
15A 1st space part
15B 2nd space part
16 communication hole
17 Insulating resin layer
18A O-ring
18B ring packing
19 Through hole for electrolyte injection
20 Gas-permeable hydrophobic diaphragm
21 Gas-permeable pressure regulating membrane
25 External lead member
25A One end side
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 holes
35A, 35B, 35C Electrolyte holding member
36 Electrode holder
36A Large diameter cylindrical part
36B Small diameter cylindrical part
36C Protection plate fitting recess
37 Through hole for electrode assembly
38 Notch for protruding terminal piece placement
39 Projecting terminal piece placement surface
40 Working electrode forming material
42 Counter electrode forming material
44 Reference electrode forming material
41, 43, 45 Projecting terminal piece
41A, 43A, 45A Base end 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 holes

Claims (4)

A casing having a gas permeable port at one end, the gas permeable port being sealed with a gas permeable hydrophobic diaphragm to form an electrolytic solution chamber in which an electrolytic solution is accommodated, and in the casing, at least a working electrode and In the constant potential electrolytic gas sensor in which the two gas detection electrodes of the counter electrode are arranged in a state where the working electrode is in contact with the gas-permeable hydrophobic diaphragm and the counter electrode is liquid-tight with respect to the working electrode,
The working electrode and the counter electrode are both plate-like in which a fluid flow path is formed which includes an electrolyte solution in the electrolyte solution chamber and a through-hole through which a test gas introduced from the gas permeation port through the gas-permeable hydrophobic diaphragm is circulated. The working electrode and the counter electrode are stacked in a state where the electrolyte solution holding member is interposed between the electrode body related to the working electrode and the electrode body related to the counter electrode. A constant potential electrolytic gas sensor, characterized in that it is configured as a single electrode structure.   In a state where the gas permeation port faces in a direction other than the upward direction so that the electrolytic solution accommodated in the electrolytic solution chamber is impregnated in the electrolytic solution holding member through the fluid flow passage formed in each of the working electrode and the counter electrode. The constant potential electrolytic gas sensor according to claim 1, wherein the constant potential electrolytic gas sensor is used.   A plurality of external lead members corresponding to each of the gas detection electrodes are arranged on the outer peripheral surface of the casing so as to extend in the stacking direction of the gas detection electrodes at positions spaced apart from each other in the circumferential direction. The constant-potential electrolysis gas sensor according to claim 1 or 2, wherein: Provided with a reference electrode having a plate-like electrode body in which a fluid flow path is formed which includes an electrolyte in the electrolyte chamber and a test gas introduced from a gas permeation port through a gas-permeable hydrophobic diaphragm. And
The electrode structure is composed of a working electrode, a counter electrode, and a reference electrode between the electrode body related to the working electrode and the electrode body related to the counter electrode, and between the electrode body related to the counter electrode and the electrode body related to the reference electrode. The constant potential electrolytic gas sensor according to any one of claims 1 to 3, wherein the constant potential electrolytic gas sensor is formed by being laminated with an electrolytic solution holding member interposed therebetween.

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