JP5992793B2 - Galvanic cell type gas sensor, method for producing anode of galvanic cell type gas sensor, and gas detector - Google Patents

Description

  The present invention relates to a galvanic cell type gas sensor, a method for producing an anode of the galvanic cell type gas sensor, and a gas detector including the galvanic cell type gas sensor.

  Currently, galvanic cell type gas sensors that have been reduced in size or thickness have been proposed. For example, by electroplating, a cathode disposed on the back surface of a diaphragm having a water repellent property into which a gas to be detected can flow and a part of a conductive material having corrosion resistance to the electrolytic solution are left as leads. An anode constructed by forming an electrode layer made of lead, and a sheet disposed between the cathode and the anode and impregnated and held in an electrolyte, and housed in a case so as to expose the diaphragm Is known (see Patent Document 1).

  In this type of galvanic cell type gas sensor, for example, when the gas to be detected is oxygen, lead constituting the electrode layer of the anode becomes lead oxide by an oxidation reaction, but reacts with an electrolyte component to react with a salt or hydroxide. It dissolves in the electrolyte in the form of Therefore, when the salt or hydroxide concentration in the electrolytic solution is saturated and lead oxide does not dissolve, the lead oxidation reaction does not proceed and the life of the sensor is exhausted. Further, when lead is consumed and disappears, the reaction as a sensor does not occur and the life as a sensor is exhausted.

JP 2002-055077 A

  However, the anode described in Patent Document 1 has a problem that the lead layer is easily peeled off, and the galvanic cell type gas sensor cannot be configured to have a desired sensor life.

The present invention has been made based on the above circumstances, and an object thereof is to provide a galvanic cell type gas sensor capable of obtaining a desired sensor life.
Another object of the present invention is to provide a method for producing an anode that can reliably produce an anode in which an electrode layer made of lead is prevented from being peeled off from a holding member and an intended function is maintained. .
Still another object of the present invention is to provide a gas detector capable of stably performing desired gas detection.

The galvanic cell type gas sensor of the present invention includes a casing in which a gas inlet opening in one side is sealed by a gas-permeable diaphragm having water repellency, and an electrolyte solution containing space in which an electrolyte solution is contained is formed, In the casing, in a galvanic cell type gas sensor comprising a cathode disposed on the surface of the gas permeable diaphragm on the liquid contact side, and a plate-shaped anode disposed via the cathode and the electrolyte,
The anode comprises a planar holding member made of a conductive material having corrosion resistance to the electrolytic solution, and an electrode layer made of lead formed on each of one side and the other side of the holding member,
The holding member is formed with a plurality of through holes including a plurality of rectangular or diamond-shaped ones whose diagonal directions extend in the same direction.
The electrode layer located on the one surface side of the holding member and the electrode layer located on the other surface side of the holding member are connected to each other via a column-shaped connecting portion formed in each through hole in the holding member. Are joined ,
The holding member in the anode is characterized in that the ratio of the total opening area of the through holes to the area of the electrode layer forming surface in the holding member is 10 to 30% .

A method for producing an anode of a galvanic cell type gas sensor of the present invention is a method for producing an anode of the above galvanic cell type gas sensor,
A plate-like electrode layer made of lead on each of one side and the other side of a planar holding member in which a plurality of through-holes including a plurality of rectangular or diamond-shaped ones whose diagonal directions extend in the same direction are formed Stacking forming materials,
Columnar connecting portions are formed in each through hole in the holding member by performing ultrasonic welding with the direction of vibration caused by the ultrasonic wave matching the long diagonal direction of the rectangular or rhomboid through hole in the holding member. And it has the process of joining the electrode layer forming material of the said one surface side, and the electrode layer forming material of the said other surface side, It is characterized by the above-mentioned.

  The gas detector of the present invention comprises the galvanic cell type gas sensor described above.

  According to the galvanic cell type gas sensor of the present invention, the columnar connecting portion formed in the rectangular or diamond-shaped through hole in the holding member is formed in close contact with the inner peripheral surface of the through hole. The bonding strength between the one-side electrode layer and the other-side electrode layer is increased, and it is possible to reliably prevent the electrode layer from peeling off from the holding member as the sensor is used. Therefore, the galvanic cell type gas sensor is It can be configured as having a sensor life of

  According to the method for producing an anode of a galvanic cell type gas sensor of the present invention, the interface portion between the electrode layer forming material and the holding member is dissolved by the vibration of the ultrasonic wave along the long diagonal direction of the rectangular or diamond-shaped through hole. When the connecting portion is formed in the through-hole, an anchor effect is obtained by the corner of the through-hole, so that the electrode layer forming materials are compared with those having, for example, round through-holes. Can be bonded with high strength, and with the use of the sensor, the electrode layer can be prevented from being peeled off from the holding member, and the desired function can be reliably produced. .

  According to the gas detector of the present invention, since the galvanic cell type gas sensor configured as having a desired life is provided, the desired gas detection can be stably performed.

It is sectional drawing which shows one structural example of the galvanic cell type gas sensor of this invention. It is a top view which shows the structure of the electrode structure in the galvanic cell type gas sensor shown in FIG. 1 in the state which abbreviate | omitted the pressure regulation film | membrane. It is the (a) top view and (b) side view which show the structure of the anode in the galvanic cell type gas sensor shown in FIG. It is a top view which shows one structural example of the holding member which comprises the anode shown in FIG. It is sectional drawing which shows the joining state in the rhombus through hole for connection part formation of the anode shown in FIG. It is a figure for demonstrating the preparation methods of the anode shown in FIG. It is sectional drawing which shows one structural example of the gas detector of this invention. It is a top view which shows the structural example of the holding member which comprises the reference anode used in the reference experiment example.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a cross-sectional view showing a configuration example of a galvanic cell type gas sensor of the present invention. FIG. 2 is a plan view showing the configuration of the electrode structure in the galvanic cell type gas sensor shown in FIG. 1 in a state where the pressure adjustment film is omitted.
The galvanic cell type gas sensor 10 uses, for example, oxygen as a detection target gas, and includes a substantially cylindrical outer casing 11 as a whole. The exterior body 11 includes a substantially bottomed cylindrical exterior body body 12 having a gas introduction through hole 12a formed at the center of the end wall, and a bottomed cylindrical exterior body cap 13 having a flange 13a at the open end. It is comprised by. The exterior body cap 13 is fitted into the opening edge of the exterior body main body 12, the opening edge of the exterior body main body 12 is crimped, and both the exterior body main body 12 and the exterior body cap 13 are The ring-shaped packing 15 having electrical insulation mounted on the other surface (outer surface) side of 13a is fixed in a state of being interposed. The exterior body main body 12 and the exterior body cap 13 are made of a metal material such as stainless steel, for example.

  An electrode structure 20, which has a substantially cylindrical shape as a whole, is fitted and disposed in the exterior body 11, and a disk-like circuit board is provided at a position on the outer side of the electrode structure 20. 18 is arranged to extend perpendicularly to the central axis of the outer package 11.

  The circuit board 18 has a conductive pattern (not shown) connected to a lead wire 46a of the cathode 38 and a lead wire 46b of the anode 30, which will be described later, on one surface (the surface facing the electrode structure 20). On the other surface (the surface facing the exterior body cap 13), an anode conductive pattern (not shown) connected to the anode 30 and a cathode conductive pattern (not shown) connected to the cathode 38 are formed. Then, one surface (inner surface) of the flange portion 13a of the outer body cap 13 is elastically contacted with the negative electrode conductive pattern formed on the other surface.

The electrode structure 20 includes a bottomed cylindrical casing 21 in which a gas intake port 21a is configured by a through hole formed in a central portion of an end wall. The casing 21 is made of a resin material such as ABS resin.
Inside the casing 21, a part of the peripheral wall of the casing 21 is formed at a position where the electrolytic solution housing space S in which the electrolytic solution is stored and the two space portions 22 a and 22 b partitioned from each other face each other. ing.

A cathode 38 is provided on the outer surface of the end wall of the casing 21 so as to cover the gas inlet 21 a in the casing 21.
The cathode 38 is an electrode made of a cathode-forming material having a disk-like electrode body 38a forming a gas contact portion and a terminal piece portion 38b extending, for example, linearly outward from the peripheral edge of the electrode body 38a in the radial direction. The body 38a is formed into a spherical shape. The cathode forming material is formed by attaching gold to the surface of a base material made of, for example, stainless steel.
The cathode 38 is disposed in a state where the electrode body 38a is convex outward, and the terminal piece portion 38b of the cathode 38 is radially formed along the end wall in the thickness of the end wall of the casing 21. The tip portion is bent in the axial direction and led out into one space 22 a of the casing 21.

  On the outer surface of the end wall of the casing 21, a gas permeable diaphragm 40 having water repellency is further attached to the electrode body 38 a of the cathode 38 by a bottomed cylindrical cap 28 to which the casing 21 is fitted and inserted. The gas inlet 21a in the casing 21 is sealed by being pressed against the outer surface. The cap 28 has a gas introduction through hole 28a at a position facing the electrode body 38a of the cathode 38 on the end wall, and the electrode body 38a of the cathode 38 is fitted into the gas introduction through hole 28a. It is in a state.

  The gas permeable diaphragm 40 is made of, for example, a fluorine resin such as FEP (tetrafluoroethylene / hexafluoropropylene copolymer) or PTFE (polytetrafluoroethylene). Here, the thickness of the gas permeable diaphragm 40 is, for example, 13 to 25 μm.

  A step portion 24 is formed on the opening end surface of the peripheral wall of the casing 21. A pressure adjusting film 42 having water repellency is stretched on the flat surface of the step portion 24, thereby forming an electrolyte solution containing space S in which the electrolyte solution is stored in the casing 21. The pressure adjusting film 42 is made of, for example, a fluorine-based resin exemplified as a constituent material of the gas permeable diaphragm 40, and a peripheral portion is fixed to the casing 21 by, for example, heat welding.

  On the inner surface of the end wall of the casing 21, for example, a vinylon nonwoven fabric is provided so as to cover the through-holes constituting the gas intake port 21a. This vinylon nonwoven fabric is for preventing lead residue from adhering to the electrode body 38a of the cathode 38 due to dissolution of lead accompanying use of the sensor.

  In addition, two cylindrical anode support portions 25 are formed on the inner surface of the end wall of the casing 21 so as to extend in the axial direction at a position apart from each other (standing upright). The plate-like anode 30 as a whole is supported in a posture extending perpendicularly to the central axis of the casing 21. A specific configuration of the anode 30 will be described later.

  The peripheral wall of the casing 21 is formed with connecting terminal mounting through holes 23a and 23b communicating with the one space portion 22a and the other space portion 22b in the casing 21 so as to extend in the radial direction. Rod-shaped connection terminals 45a and 45b are mounted in the through holes 23a and 23b. The terminal piece portion 38b of the cathode 38 is electrically connected to the tip of one connection terminal 45a. Further, the other connection terminal 45b is provided in a state in which the tip portion extends through a partition wall defining the other space portion 22b and is in contact with the other surface (surface on the anode 30 side) of the electrolyte solution holding member 41. Yes. And the front-end | tip part of the other connection terminal 45b is electrically connected to the lead connection part 31c of the holding member 31 in the anode 30 mentioned later. One space 22a and the other space 22b are sealed with, for example, an epoxy resin adhesive 47 filled therein.

The lead wire 46a of the cathode 38 extends axially outward along the peripheral wall of the casing 21 while one end thereof is connected to the outer end surface of the one connection terminal 45a exposed on the outer peripheral surface of the casing 21. The side portions are arranged so as to be bent radially inward and extend along the opening end surface of the casing 21. The other end of the lead wire 46 a of the cathode 38 is connected to a conductive pattern formed on one surface of the circuit board 18.
The lead wire 46 b of the anode 30 is axially oriented along the peripheral wall of the casing 21 in a state where a part of the lead wire 46 b of the anode 30 is connected to the outer end surface of the other connection terminal 45 b exposed on the outer peripheral surface of the casing 21. It extends outward, is bent along the peripheral surface of the cap 28 and extends along the outer surface of the cap 28, and the other end portion extends axially outward along the peripheral wall of the casing 21. Further, it is disposed so as to be bent radially inward and to extend along the opening end surface of the casing 21. The other end of the lead wire 46 b of the anode 30 is connected to a conductive pattern formed on one surface of the circuit board 18. The lead wire 46 a of the cathode 38 and the lead wire 46 b of the anode 30 are pressed against the circuit board 18 by a sealing member 19 made of, for example, an O-ring disposed on the step portion 24 of the casing 21.

  Thus, as shown in FIG. 3, the anode 30 in the galvanic cell type gas sensor 10 includes a plate-like holding member 31 made of a conductive material having corrosion resistance to the electrolyte, for example, nickel, and the holding member. It is comprised by the one surface side electrode plate 35a and the other surface side electrode plate 35b which consist of the lead which comprises the electrode layer, and were provided in one surface and the other surface of 31, respectively.

The holding member 31 is formed with a plurality of connecting portion forming through holes including a plurality of rectangular or diamond-shaped ones whose diagonal directions extend in the same direction, and the anode support portion 25 in the casing 21 is fitted and inserted. A through hole 33 for inserting an anode support portion is formed.
As shown in FIG. 4, the holding member in this example has a substantially flat plate shape in which both end edges in the longitudinal direction (left and right direction in FIG. 4) are formed in an arc shape along the inner peripheral edge of the casing 21. It has a form in which notches are formed on both side edges (vertical direction in FIG. 4). One notch has a form along the outer peripheral edge of the partition wall that partitions one space 22 a of the casing 21. An anode support insertion hole 33 is formed at a substantially central position of each side 31a. In the region on the outer side in the longitudinal direction with respect to the formation position of the anode support portion insertion through hole 33, four connection portion formation round through holes 32a are formed side by side, for example, at equal intervals in the width direction. A connecting portion forming rhombus through hole 32b is formed at a position on one side edge side of the anode support portion insertion through hole 33 in the width direction with the long diagonal direction coinciding with the width direction, and the other side edge side. A circular through hole 32a for forming a connecting portion is formed at the position. Further, one connecting portion forming rhombus through hole 32b is formed in a region on the inner side of the anode support portion insertion through hole 33 in the longitudinal direction and on the other side edge side in a state where the long diagonal direction coincides with the width direction. Has been. In the central portion 31b, seven connecting portion forming round through holes 32a are formed in a staggered pattern in a region on one side edge side in the width direction.

Each of the connecting portion forming round through holes 32a in the holding member 31 has, for example, the same diameter.
Each of the connecting portion forming rhombus-shaped through holes 32b is formed in a state in which the diagonal directions coincide with each other.
The ratio of the sum of the opening areas of the connecting portion forming through holes 32a and 32b in the holding member 31 to the area of the electrode layer forming surface (electrode plate arrangement region) of the holding member 31 is preferably 10 to 30%, for example. More preferably, it is 15 to 30%. By adopting such a configuration, it is possible to suppress the deformation of the electrode plate itself while ensuring sufficient bonding strength between the one-side electrode plate 35a and the other-side electrode plate 35b. On the other hand, when the ratio is too small, the holding force of lead (electrode plate) is weak, the electrode plate is likely to be peeled off from the holding member 31 due to an external impact, and the ratio is excessive. Therefore, the mechanical strength of the holding member 31 is lowered, and it is difficult to maintain the shape of the anode 30 itself.
Moreover, it is preferable that the ratio of the connection part formation rhombus penetration hole 32b to all the connection part formation through holes is 15 to 100%, for example. By adopting such a configuration, it is possible to reliably obtain a sufficient bonding strength between the one-side electrode plate 35a and the other-side electrode plate 35b, and that the electrode plate is peeled off from the holding member 31 with use. It can be surely prevented.

  The one-side electrode plate 35a and the other-side electrode plate 35b are joined to each other by columnar connecting portions 37 formed in the connecting portion forming through holes 32a and 32b in the holding member 31. Specifically, in the connecting portion forming rhombus through hole 32b of the holding member 31, as shown in FIG. 5A, the connecting portion 37 is in close contact with the inner peripheral surface of the connecting portion forming rhombus through hole 32b. It is formed in a state. On the other hand, in the connecting portion forming round through hole 32a of the holding member 31, as shown in FIG. 5B, the connecting portion 37 is between the inner peripheral surface of the connecting portion forming round through hole 32a. It is formed with a minute gap C interposed.

The one side electrode plate 35a and the other side electrode plate 35b are substantially the same as the holding member 31 except that the other side edge side cutout in the width direction is formed larger than the cutout of the holding member 31. It has an outer shape. Therefore, in the anode 30 described above, a part of the central portion 31b of the holding member 31 is exposed to the outside, thereby forming a lead connection portion 31c with the other connection terminal 45b. .
Further, anode support portion insertion through holes 36a and 36b continuous with the anode support portion insertion through hole 33 in the holding member 31 are formed in the one surface side electrode plate 35a and the other surface side electrode plate 35b (FIG. 6). (See (a).)
The thicknesses of the one-side electrode plate 35a and the other-side electrode plate 35b can be appropriately set in relation to, for example, an amount corresponding to a desired sensor life.

The anode 30 having the above-described configuration can be manufactured as follows.
First, as shown in FIG. 6A, by forming anode support portion insertion through holes 36a and 36b at predetermined positions in a plate-like electrode layer forming material made of lead, The other side electrode plate 35b is manufactured, and the connecting portion forming round through hole 32a, the connecting portion forming rhombus through hole 32b, and the anode support portion are formed at predetermined positions in the plate-shaped holding member forming material made of nickel, for example. The holding member 31 is produced by forming the insertion through-hole 33. Here, the holding member 31 can be produced by, for example, etching or pressing.
Next, as shown in FIG. 6B, the one-side electrode plate 35 a is stacked on one surface of the holding member 31, and the other-side electrode plate 35 b is stacked on the other surface of the holding member 31. The ultrasonic vibration is performed by arranging the ultrasonic vibration direction (indicated by a white arrow in FIG. 6B) to coincide with the long diagonal direction of the connecting portion forming rhombus through hole 32b of the holding member 31. Thus, the columnar connecting portion 37 is formed inside each of the connecting portion forming round through hole 32a and the connecting portion forming rhombus through hole 32b of the holding member 31, thereby forming the one side electrode plate 35a and the other side electrode plate. Thus, the anode 30 having the above-described configuration can be obtained. Here, the ultrasonic frequency is, for example, 15 to 40 kHz, and the ultrasonic oscillation time is, for example, 0.1 to 0.3 seconds. In the case where ultrasonic welding is performed with the ultrasonic vibration direction being made to coincide with the short diagonal direction (longitudinal direction) of the connecting portion forming rhombus through hole 32b, for example, the electrode plate is stretched in the vibration direction. It may become impossible to accommodate in the casing 21 due to the dimensional deviation.

Thus, the anode 30 is formed by the ultrasonic vibration along the long diagonal direction of the connecting portion forming rhombus through hole 32a of the holding member 31, and the interface portion with the holding member 31 in the one-side electrode plate 35a and others. When the interface portion of the surface side electrode plate 35b with the holding member 31 is melted to form the columnar connecting portion 37 in the connecting portion forming rhombus through hole 32a, the corner portion of the connecting portion forming rhombus through hole 32a is formed. Therefore, the columnar connecting portion 37 formed in the connecting portion forming rhombus through hole 32b of the holding member 31 is formed in close contact with the inner peripheral surface of the connecting portion forming rhombus through hole. Will be. For this reason, the one-side electrode plate 35a and the other-side electrode plate 35b can be joined with a higher strength than, for example, those in which a round through-hole is formed. The peeling from the holding member 31 can be suppressed and the intended function can be reliably maintained. Further, it is possible to reliably prevent the dimensional deviation of the anode 30 during the manufacturing process.
Therefore, according to the galvanic cell type gas sensor 10 having the above-described configuration including the anode 30, it is ensured that the one-side electrode plate 35a and the other-side electrode plate 35b are peeled off from the holding member 31 as the sensor is used. The galvanic cell type gas sensor 10 can be configured to have a desired sensor life.

Hereinafter, the gas detector of the present invention including the galvanic cell type gas sensor 10 will be described.
FIG. 7 is a cross-sectional view showing a configuration example of the gas detector of the present invention.
This gas detector includes a housing that is flat as a whole and includes a rear housing member 51 and a front housing member 52 that is connected and fixed to the rear housing member via a ring-shaped packing. A buzzer arrangement portion 52a is formed in the left side region of the front-side housing member 52, and the alarm buzzer 53 is arranged so that the sound generation portion is on the upper surface side while being accommodated in the buzzer arrangement portion 52a. Yes. A cylindrical sensor arrangement portion 52b whose upper end is opened in FIG. 7 is formed in the right region of the front-side housing member 52, and the galvanic cell described above is accommodated in the sensor arrangement portion 52b. The gas sensor 10 is held in a state of being fixed by a sensor cap 52c that is detachably fitted to the sensor arrangement portion 52b. In FIG. 7, 55 is a flat circuit board for control, 56 is a panel display mechanism, and 58 is a so-called button-type battery constituting a driving power source.

  Thus, according to the above gas detector, since the galvanic cell type gas sensor 10 configured to have an intended life is provided, the intended gas detection can be stably performed. .

Hereinafter, experimental examples performed for confirming the effects of the present invention will be described.
<Experimental example 1>
According to the configuration shown in FIGS. 3 and 4, an anode (30) for a galvanic cell type gas sensor according to the present invention was produced. The specific configuration of the anode (30) is as follows.

[Holding member (31)]
・ Material: Nickel,
・ Thickness: 0.1 mm,
-Hole diameter of the connecting portion forming round through hole (32a): φ0.5mm, number: 17,
-Opening dimension in the long diagonal direction of the diamond-shaped through hole (32b) for connecting part formation: 1.2 mm, opening dimension in the short diagonal direction: 0.7 mm, number: 4 (the connection occupying all the through holes for forming the connecting part) (Ratio of rhombus-shaped through holes for part formation: about 19%)
The ratio of the sum of the opening areas of the through holes (32a, 32b) for forming the coupling portion to the area of the electrode plate arrangement region of the holding member (31): 13.5%
[One side electrode plate (35a) and other side electrode plate (35b)]
・ Material: Lead,
・ Thickness: 0.5mm
· The area of Taise' surface of the holding member: about 29 mm ^2,
・ Lead amount: equivalent to the sensor life of about 2 years [processing conditions for ultrasonic welding]
・ Vibration direction by ultrasonic waves: Long diagonal direction of the diamond-shaped through hole for forming the connecting portion,
・ Ultrasonic frequency: 39.5 kHz,
・ Ultrasound oscillation time: 0.18 seconds

A galvanic cell type gas sensor according to the present invention was produced according to the configuration shown in FIG. 1 using the above-mentioned anode, and the galvanic cell type gas sensor was subjected to the sensor life test shown below. It was confirmed that the expected sensor life could be obtained.
<Sensor life test>
In an environment where the oxygen concentration at a temperature of 25 ° C. is 100%, the galvanic cell type gas sensor is left in a state where the galvanic cell type gas sensor is operated (5-fold acceleration test).
And when 5 months have passed, if it is confirmed that even a part of the electrode plate (lead) constituting the anode is held by the holding member (nickel plate), depending on the amount of lead Evaluation was performed assuming that the expected sensor life was obtained.

<Reference Experimental Example 1>
In Reference Example 1, a reference anode having the same configuration as that of Test Example 1 was prepared except that the reference holding member (311) manufactured according to the configuration shown in FIG. 8 was used. did. The hole diameter of the connecting portion forming round through hole (32a) in the reference anode holding member (311) is φ0.5 mm, and the number of connecting portion forming round through holes (32a) is 23. (The ratio of the sum of the opening areas of the through holes (32a) for forming the connecting portion to the area of the electrode plate arrangement region of the holding member (31): about 9%).
A galvanic cell type gas sensor having the same configuration as that of the experimental example 1 is manufactured except that this reference anode is used, and the galvanic cell type gas sensor is obtained by the same method as in the experimental example 1. As a result of the life test, it was confirmed that the electrode plate portion held by the holding member did not exist at the time when 5 months passed, and that it was shorter than the expected sensor life according to the lead amount of the anode. It was.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, the holding member in the anode is not a plate-like member, and for example, a wire mesh can be used. The material is not limited to nickel as long as it has corrosion resistance to the electrolytic solution, and for example, stainless steel can be used. Furthermore, the shape of the connecting portion forming through hole in the holding member is not limited to the rhombus shape, and may be a rectangular shape.

DESCRIPTION OF SYMBOLS 10 Galvanic cell type gas sensor 11 Exterior body 12 Exterior body main body 12a Gas introduction through-hole 13 Exterior body cap 13a collar 15 Packing 18 Circuit board 19 Seal member 20 Electrode structure 21 Casing 21a Gas intake S Electrolyte containing space 22a Spacer 22b Other space 23a, 23b Connection terminal mounting through hole 24 Step part 25 Anode support part 28 Cap 28a Gas introduction through hole 30 Anode 31, 311 Holding member 31a Side part 31b Central part 31c Lead connection part 32a Connecting part forming round through hole 32b Connecting part forming rhombus through hole 33 Anode supporting part insertion through hole
35a One side electrode plate (electrode layer)
36a Through hole for insertion of anode support part 35b Other side electrode plate (electrode layer)
36b Anode support insertion hole 37 Connecting portion 38 Cathode 38a Electrode body 38b Terminal piece 40 Gas permeable diaphragm 41 Electrolyte holding member 42 Pressure adjusting membrane 45a One connection terminal 45b The other connection terminal 46a, 46b Lead wire 47 Adhesive 51 Rear side housing member 52 Front side housing member 52a Buzzer holding portion 52b Sensor placement portion 52c Sensor cap 53 Alarm buzzer 55 Control circuit board 56 Panel-shaped display mechanism 58 Battery

Claims (3)

A gas inlet opening on one side is sealed by a gas permeable diaphragm having water repellency, and a casing in which an electrolytic solution containing space is formed to contain an electrolytic solution therein, and the gas permeable diaphragm in the casing In a galvanic cell type gas sensor comprising a cathode disposed on the surface of the liquid contact side, and a plate-like anode disposed via the cathode and an electrolyte,
The anode comprises a planar holding member made of a conductive material having corrosion resistance to the electrolytic solution, and an electrode layer made of lead formed on each of one side and the other side of the holding member,
The holding member is formed with a plurality of through holes including a plurality of rectangular or diamond-shaped ones whose diagonal directions extend in the same direction.
The electrode layer located on the one surface side of the holding member and the electrode layer located on the other surface side of the holding member are connected to each other via a column-shaped connecting portion formed in each through hole in the holding member. Are joined ,
The galvanic cell type gas sensor characterized in that the holding member in the anode has a ratio of the sum of the opening areas of the through holes to the area of the electrode layer forming surface in the holding member of 10 to 30% . A method for producing an anode of a galvanic cell gas sensor according to claim 1,
A plate-like electrode layer made of lead on each of one side and the other side of a planar holding member in which a plurality of through-holes including a plurality of rectangular or diamond-shaped ones whose diagonal directions extend in the same direction are formed Stacking forming materials,
Columnar connecting portions are formed in each through hole in the holding member by performing ultrasonic welding with the direction of vibration caused by the ultrasonic wave matching the long diagonal direction of the rectangular or rhomboid through hole in the holding member. A method for producing an anode of a galvanic cell type gas sensor, comprising the step of joining the electrode layer forming material on the one surface side and the electrode layer forming material on the other surface side. A gas detector comprising the galvanic cell type gas sensor according to claim 1.

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