JPH0949823A - Electrochemical gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive electrochemical gas sensor which can be reduced in size. SOLUTION: An electrochemical gas sensor is provided with a conductive positive electrode case 2, a positive electrode 1 which is housed in the case 2 and electrochemically reduces an oxidizing gas, a negative electrode 6, a diaphragm 7 which limits the supply of the oxidizing gas to the positive electrode 1, and an electrolytic solution 8 and the negative electrode 6, diaphragm 7, and electrolytic solution 8 are housed in the case 2 and, at the same time, the case 2 is sealed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical gas sensor for measuring the concentration of a gas dissolved in a gas phase or in water, such as oxygen and hydrogen.

[0002]

2. Description of the Related Art In order to measure the concentration of an oxidizing gas such as oxygen dissolved in a gas phase or water, generally,
A galvanic battery type or a polaro type oxygen gas sensor, which is an electrochemical oxygen gas sensor, is used.

Both of the sensors are basically composed of a positive electrode, a negative electrode, a diaphragm provided outside the positive electrode for limiting the permeation of oxygen to the positive electrode, an electrolytic solution, and a resin container for containing these. Has been done.

In addition, the principle of measurement is the same, and when the positive electrode and the negative electrode are electrically connected outside the container, a reduction reaction of oxygen occurs at the positive electrode and an oxidation reaction of the reducing active material of the negative electrode occurs at the same time. At that time, the oxygen gas concentration is known from the current value by utilizing the fact that the current flowing between both electrodes is proportional to the oxygen gas concentration.

In the former, the positive electrode and the negative electrode are connected via a resistor and always outputs in proportion to the oxygen concentration by itself, whereas in the latter, a constant voltage is applied between both electrodes from the outside. It is different in that the output proportional to the oxygen concentration is obtained only at that time.

The same applies to other oxidizing gases such as ozone and chlorine.

On the other hand, in order to measure the concentration of a reducing gas, such as hydrogen, dissolved in the gas phase or in water, a galvanic cell type or polaro type hydrogen sensor which is an electrochemical hydrogen sensor is generally used.

Both of the sensors are basically composed of a positive electrode, a negative electrode, a diaphragm provided outside the negative electrode for limiting the permeation of hydrogen to the negative electrode, an electrolytic solution, and a resin container for containing these. Has been done.

The measuring principle is the same as that of the oxidizing gas sensor. When the positive electrode and the negative electrode are electrically connected to each other outside the container, an oxidation reaction of hydrogen occurs in the negative electrode and a reduction reaction of the oxidizing active material of the positive electrode occurs at the same time. . At that time, the hydrogen concentration is known from the current value by utilizing the fact that the current flowing between both electrodes is proportional to the hydrogen concentration.

In the former, the positive electrode and the negative electrode are connected via a resistor and always outputs in proportion to the hydrogen concentration, whereas the latter applies a constant voltage from the outside between both electrodes. It is different in that the output proportional to the oxygen concentration is obtained only at that time.

The same applies to other reducing gases such as carbon monoxide.

[0012]

As described above, in the electrochemical gas sensor, the gas concentration is known from the current value flowing between the positive electrode and the negative electrode. Therefore, it is necessary to take out a lead wire from the positive electrode and the negative electrode housed in the resin container together with the electrolytic solution to the outside of the container and electrically connect them.

Therefore, it is very difficult to seal the lead take-out port, and there is a problem that the electrolytic solution is liable to leak from the sealing part unless a strong seal is made, and the lead take-out and the sealing are very complicated in manufacturing. It is a process.

Further, since the life of the sensor is limited by the weight of the negative electrode in the case of an oxygen sensor and by the weight of the positive electrode in the case of a hydrogen sensor, for manufacturing a sensor having a longer life, simply use the negative electrode or the negative electrode. Although it is sufficient to increase the size of the positive electrode, there is a problem in that the number of leads must be increased because the current condensing density decreases with one lead.

Therefore, an object of the present invention is to provide an electrochemical gas sensor which can be miniaturized without the need for taking out leads from the inside of the electrolytic solution to the outside as in the prior art.

[0016]

An electrochemical gas sensor according to a first aspect of the present invention comprises a positive electrode case having conductivity, a positive electrode electrochemically reducing an oxidizing gas provided in the case, and a negative electrode. The positive electrode case comprises a diaphragm that limits the amount of oxidizing gas supplied to the positive electrode, and an electrolytic solution. The negative electrode, the diaphragm, and the electrolytic solution are arranged in a positive electrode case so that the oxidizing gas can be introduced into the positive electrode through the diaphragm. In addition, the positive electrode case is sealed.

An electrochemical gas sensor according to a second aspect of the invention is a positive electrode that electrochemically reduces an oxidizing gas, a negative electrode case having a negative electrode and having conductivity, and a supply amount of the oxidizing gas to the positive electrode is limited. And a electrolytic solution,
The positive electrode, the diaphragm, and the electrolytic solution are disposed in the negative electrode case and the negative electrode case is sealed so that the oxidizing gas can be introduced into the positive electrode through the diaphragm.

An electrochemical gas sensor according to a third aspect of the present invention is a positive electrode case having conductivity, a positive electrode electrochemically reducing the oxidizing gas provided in the case, and a negative electrode having conductivity provided with a negative electrode. A case, a diaphragm for limiting the amount of oxidizing gas supplied to the positive electrode, and an electrolytic solution are provided, and the diaphragm is arranged on the positive electrode or the negative electrode case so that the oxidizing gas can be introduced into the positive electrode through the diaphragm. In addition, the positive electrode case and the negative electrode case are sealed.

An electrochemical gas sensor according to a fourth aspect of the present invention comprises a negative electrode case having conductivity, a negative electrode electrochemically oxidizing a reducing gas provided in the case, and a positive electrode.
The positive electrode, the diaphragm, and the electrolytic solution are arranged in a negative electrode case so that a reducing gas is supplied to the negative electrode and an electrolytic solution is provided so that the reducing gas can be introduced into the negative electrode through the diaphragm. And the negative electrode case is sealed.

An electrochemical gas sensor according to a fifth aspect of the present invention limits a supply amount of reducing gas to the negative electrode, which has a negative electrode which electrochemically oxidizes a reducing gas, a positive electrode case which is provided with a positive electrode, and which has conductivity. And a electrolytic solution,
The positive electrode, the diaphragm, and the electrolytic solution are arranged in the positive electrode case and the positive electrode case is sealed so that the reducing gas can be introduced into the negative electrode through the diaphragm.

An electrochemical gas sensor according to a sixth aspect of the present invention is a negative electrode case having conductivity, a negative electrode electrochemically oxidizing a reducing gas provided in the case, and a positive electrode having conductivity provided with a positive electrode. A case, a diaphragm for limiting the amount of reducing gas supplied to the negative electrode, and an electrolytic solution are provided, and the diaphragm is arranged on the positive electrode or the negative electrode case so that the reducing gas can be introduced into the negative electrode through the diaphragm. In addition, the positive electrode case and the negative electrode case are sealed.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an electrochemical gas sensor according to the present invention, particularly an oxidizing gas sensor, will be described below. Here, the oxidizing gas is oxygen.

A sensor according to an embodiment of the present invention comprises a positive electrode case having conductivity, a positive electrode made of platinum for electrochemically reducing oxygen provided in the case, lead, and a highly corrosion resistant metal. A negative electrode made of the clad material of
A negative electrode having an oxygen introduction hole for introducing oxygen to the positive electrode, a diaphragm provided on the highly corrosion-resistant metal surface side of the negative electrode so as not to leak from the oxygen introduction hole, and limiting the amount of oxygen supplied to the positive electrode, and electrolysis The negative electrode is arranged in the case so that the lead side of the negative electrode is the inner side and the positive electrode and the diaphragm are in contact with each other through the oxygen introduction hole of the negative electrode, and the peripheral edge of the negative electrode and the peripheral edge thereof are in contact with each other. The negative electrode and the positive electrode case are caulked and sealed with a gasket interposed in the positive electrode case portion.

Leads are attached to the corrosion-resistant metal surfaces of the positive electrode case and the negative electrode.

Needless to say, the space formed by the negative electrode, the diaphragm and the positive electrode case is filled with the electrolytic solution.

Therefore, unlike the conventional sensor in which the positive electrode and the negative electrode are housed in the resin container, the sensor of the present invention does not need to take out the lead wire from the inside of the sensor.

Further, since the positive electrode or the negative electrode is arranged in the conductive case or at the upper edge of the case opening, only the negative electrode or / and the positive electrode and the electrolytic solution are stored in the case, and the structure is simple. It is easy to downsize.

When the negative electrode case is used, most of the internal surface area of the case can be used as the negative electrode, so that an electrochemical gas sensor having a longer life can be provided.

Here, the positive electrode case is covered with the negative electrode and the diaphragm, but it may be only with the diaphragm or a separate lid may be provided. If another sealing lid is used, it must be shaped so that oxygen can be taken into the septum well.

When the negative electrode case is used, the positive electrode may be sealed with a diaphragm, a diaphragm, or a separately provided sealing lid. If another sealing lid is used, it must be shaped so that oxygen can be taken into the septum well.

When a sealing lid is separately used, the material may be resin or corrosion resistant metal.

Further, although the positive electrode obtained by plating a corrosion resistant metal with platinum is spot-welded to the positive electrode case here, platinum may be formed on the corrosion resistant metal by sputtering, vapor deposition or the like, or platinum may be formed on the corrosion resistant metal plate. What was plated, sputtered, or vapor-deposited may be spot-welded in the case, or platinum may be directly plated, vapor-deposited or sputtered on the case. In this case, it is necessary to have a structure in which the diaphragm and the positive electrode can come into contact with each other. For example, it is conceivable that the diaphragm has a case shape provided with a pedestal for forming the positive electrode or the diaphragm has a different shape.

Further, platinum and gold, platinum and iridium, platinum and platinum alloys such as ruthenium, gold, and the like are sufficient if oxygen can be reduced. (In the case of a reducing gas, it is a portion corresponding to the negative electrode.) In addition, the positive electrode case or the negative electrode case may be made of corrosion-resistant metal such as stainless steel or titanium, and exhibits corrosion resistance and electrical conductivity. Anything is sufficient. The shape is not limited to the U-shaped cross-sectional view and the circular shape or the rectangular shape in the top view shown in the embodiment, and may be particularly limited as long as it can function as a gas sensor and can be assembled. Absent.

Although a solution is used as the electrolytic solution here, a gelled electrolytic solution may be used.

The sealing is not limited to caulking, and may be laser sealing, welding or the like, and depending on the sealing material, sealing may be done by heat sealing, ultrasonic welding or the like.

It should be noted that "to allow the oxidizing or reducing gas to be introduced into the positive electrode through the diaphragm" means that one surface of the diaphragm can contact the oxidizing or reducing gas and one surface of the positive electrode is at least the positive electrode. It means a state in which a part is in contact with and the electrolytic solution is present at the contact interface.

Although the oxygen sensor has been described above as one embodiment, the same applies to other oxidizing gases, ozone, chlorine and the like. In the case of reducing gas, the positive electrode in the case of oxidizing gas is the negative electrode, and the negative electrode is the positive electrode (lead dioxide)
As a result, the configuration is similar to that described above. in addition,
It is needless to say that the same configuration as the above can be used in common with other inventions.

[0038]

The present invention will be described in detail below with reference to preferred embodiments.

[Embodiment 1] FIG. 1 is a sectional structural view of an electrochemical oxygen sensor according to an embodiment of the present invention.

In the figure, 1 is 2 mm in diameter and 0.
This is a positive electrode in which a 7 mm titanium cylinder is plated with 3 μm platinum (Pt).

Reference numeral 2 designates a titanium positive electrode case having a U-shaped cross section and having a conductivity of 10 mm in diameter and 0.2 m in thickness.
m, depth 1.2 mm. 6 is lead 4 (thickness 0.3m
m) and a titanium substrate 5 (thickness 0.1 mm), which is a negative electrode made of a clad material.

Reference numeral 3 denotes an oxygen introduction hole (diameter 4 mm) for introducing oxygen to the positive electrode 1 formed in the negative electrode, which is formed in the center of the negative electrode here.

Reference numeral 7 is a diaphragm made of polyethylene having a thickness of 10 μm, which is welded to the titanium surface side of the negative electrode 6, and covers the oxygen introducing hole 3.

Reference numeral 8 is an electrolytic solution composed of a mixed aqueous solution of acetic acid and potassium acetate, and 9 is a synthetic resin gasket. 10,
Reference numeral 11 is a lead wire for the positive electrode and the negative electrode.

The positive electrode 1 is spot-welded to the central portion of the positive electrode case 2.

The negative electrode 6 is arranged in the positive electrode case with its lead surface facing downward, and the negative electrode 6 and the positive electrode case 2 are caulked and sealed. At this time, the positive electrode 1 is in contact with the diaphragm 7 through the oxygen introduction hole 3 of the negative electrode 6.

Positive and negative electrode leads 10 and 11 are spot-welded to the titanium substrate 5 of the positive electrode case 2 and the negative electrode 6, respectively.

Needless to say, the space formed by the negative electrode 6, the diaphragm 7 and the positive electrode case 2 is filled with the electrolytic solution 8.

The positive electrode 1 is arranged at the center of the positive electrode case in order to prevent the positive electrode 1 from being easily crushed when pressed from above.

FIG. 2 shows a sectional structure view of a conventional galvanic cell type oxygen sensor.

In the figure, 13 is a container made of ABS resin (a hollow cylindrical container having a diameter of 28 mm and a height of 42 mm),
Reference numeral 14 is an epoxy resin, and 15 is a lead outlet for taking out an electric current from the inside of the container to the outside.

The other reference numerals are the same as those shown in FIG.

This sensor has a positive electrode 1 made of a titanium disc having a diameter of 2 mm and a thickness of 1 mm, which is plated with 3 μm of platinum (Pt), and a negative electrode 12 made of lead (1 × 10 × 3 mm).
A diaphragm 7 made of polyethylene having a thickness of 10 μm located outside the positive electrode 1 and an electrolytic solution 8 made of a mixed aqueous solution of acetic acid and potassium acetate are housed in a container 13 made of ABS resin.

Lead wires 10 and 11 made of titanium and provided on the positive electrode 1 and the negative electrode 12 housed in the container 13.
Is led out to the outside of the container through a lead outlet 15 provided in the resin container 13.
5 is sealed with an epoxy resin 14.

[Embodiment 2] FIG. 3A is a sectional structural view of an electrochemical oxygen sensor according to another embodiment of the present invention, and FIG. 3B is a donut-shaped titanium disc for welding a diaphragm. It is sectional drawing concerning one Example.

In the figure, 7 is a diaphragm made of polyethylene having a thickness of 10 μm, and 100 is a diaphragm made of a titanium donut-shaped disk in which a titanium disk having a diameter of 9.5 mm and a thickness of 0.2 mm is perforated with a diameter of 8 mm. 7 is welded, and 3 μm of platinum (Pt) is vapor-deposited on the donut-shaped titanium disk side of the positive electrode.

102 has a diameter of 10 mm and a thickness of 0.2 mm,
A negative electrode case made of titanium having a depth of 1.0 mm and having a U-shaped cross section, and 4 is a lead (thickness 0.3 mm) negative electrode provided inside the bottom surface of the negative electrode case 102 and on the lower half of the inner surface of the peripheral side. Is.

Reference numeral 8 is an electrolytic solution composed of a mixed aqueous solution of acetic acid and potassium acetate, and 9 is a synthetic resin gasket. 10,
Reference numeral 11 is a lead wire for the positive electrode and the negative electrode.

The positive electrode 100 is arranged in the negative electrode case with the platinum surface of the positive electrode 100 facing downward so as not to come into contact with the negative electrode lead 4, and the positive electrode 100 and the negative electrode case 102 are disposed.
And are caulked and sealed via a gasket 9. At this time, the space formed by the negative electrode, the positive electrode, and the case is filled with the electrolytic solution 8.

The positive and negative electrode leads 10 and 11 are spot-welded to the titanium disks of the negative electrode case 102 and the positive electrode 100, respectively.

Although platinum, which is the oxygen reducing substance of the positive electrode 100, is formed by vapor deposition here, it may be formed by plating on a titanium substrate.

For example, a titanium substrate may be formed in a mesh shape, and platinum may be plated on this substrate to weld a diaphragm on one side, or a small hole may be formed so that oxygen can be smoothly transferred without using the substrate. A diaphragm may be welded to one side of the opened platinum plate.

In welding, it is desirable to weld at the peripheral edge of the diaphragm in order to maximize the reaction area.

[Embodiment 3] FIG. 4 is a sectional structural view of an electrochemical hydrogen sensor according to an embodiment of the present invention.

In the figure, reference numeral 1'denotes a negative electrode in which a titanium cylinder having a diameter of 2 mm and a height of 0.7 mm is plated with platinum (Pt) of 3 μm.

Reference numeral 2'denotes a titanium negative electrode case having a U-shaped cross section and having a diameter of 10 mm and a thickness of 0.2 m.
m, depth 1.2 mm. Reference numeral 6'denotes a positive electrode obtained by plating a titanium substrate 5 '(thickness 0.1 mm) with lead dioxide 4'.

Reference numeral 3'denotes a hydrogen introduction hole (diameter 4 mm) for introducing hydrogen into the negative electrode 1'formed on the positive electrode, which is formed here at the center of the positive electrode.

Reference numeral 7'denotes a diaphragm made of polyethylene having a thickness of 10 μm, which is welded to the titanium surface side of the positive electrode 6 ', and covers the hydrogen introducing hole 3'.

Reference numeral 8'denotes an electrolytic solution composed of a mixed aqueous solution of acetic acid and potassium acetate, and 9'denotes a synthetic resin gasket. 1
Reference numerals 0'and 11 'are negative and positive and negative lead wires.

The negative electrode 1'is spot-welded to the central portion of the negative electrode case 2 '.

The positive electrode 6'is arranged in the negative electrode case with the lead dioxide surface facing downward, and the positive electrode 6'and the negative electrode case 2'are caulked and sealed. At this time, the negative electrode 1'is in contact with the diaphragm 7'through the hydrogen introducing hole 3'of the positive electrode 6 '.

The positive and negative electrode leads 10 'and 11' are spot-welded to the titanium substrate 5'of the negative electrode case 2'and the positive electrode 6 ', respectively.

Needless to say, the space formed by the positive electrode 6 ', the diaphragm 7'and the negative electrode case 2'is filled with the electrolytic solution 8'.

The reason why the negative electrode 1'is arranged in the center of the negative electrode case is to prevent it from being easily crushed when pressed from above.

[Embodiment 4] FIGS. 5 and 6 are explanatory views of an electrochemical oxygen sensor according to another embodiment of the present invention. In these figures, (a) is a sensor plan view,
(B) is a sectional view of the sensor.

In FIG. 5, reference numeral 202 denotes a negative electrode case made of titanium having a diameter of 10 mm, a thickness of 0.2 mm and a depth of 0.6 mm, and having a substantially U-shaped cross section and a circular plane. A lead negative electrode (thickness: 0.3 mm) provided on the inner surface of the bottom surface and the lower half of the inner surface on the peripheral side.

201 has a diameter of 10 mm and a thickness of 0.2 m.
m is a positive electrode case made of titanium and having a depth of 0.3 mm and having a substantially U-shaped cross section and a circular plane shape, and an oxygen introduction hole having a diameter of 7 mm is provided on the bottom surface of the case. Here, only the introduction holes are provided, but radial or lattice-shaped crosspieces may be provided for reinforcement.

Reference numeral 7 is a diaphragm made of polyethylene having a diameter of 9.6 mm and a thickness of 10 μm, and is welded to the inside of the positive electrode case 201 so as not to leak liquid so as to seal the oxygen introduction hole of the positive electrode case 201. Reference numeral 200 denotes a positive electrode, which is 3 μm of platinum (Pt) deposited on the inner surface of the case of the diaphragm 7.
It is.

The positive electrode case 201 and the negative electrode case 202 are so constructed that they can be caulked and sealed to each other.

Reference numeral 8 is an electrolytic solution prepared by gelling a mixed aqueous solution of acetic acid and potassium acetate, and 9 is a synthetic resin gasket.
Reference numerals 10 and 11 are positive and negative lead wires.

The positive electrode 200 is arranged so as not to come into contact with the lead 4, which is the negative electrode, and faces the negative electrode case with the platinum surface of the positive electrode 200 facing downward. The positive electrode case 201 and the negative electrode case 202 have the gasket 9 interposed therebetween. The entire circumference is caulked and sealed. At this time, the space formed by the negative electrode, the positive electrode, and the case is filled with the electrolytic solution 8. The positive and negative electrode leads 10 and 11 are spot-welded to the negative electrode case 202 and the positive electrode case 201, respectively.

Here, platinum of the positive electrode 200 is formed by vapor deposition on the diaphragm, but it may be formed by plating or the like on both sides of a platinum plate or a titanium substrate. In this case, needless to say, in order for the electrolytic solution to exist at the contact interface between the positive electrode and the diaphragm, the electrolytic solution introduction hole for introducing the electrolytic solution into the interface must be formed in the positive electrode. However, when the positive electrode is formed on the diaphragm by vapor deposition or sputtering,
Since the fine pores are formed in the positive electrode layer, a state in which the electrolytic solution exists at the interface between the diaphragm and the positive electrode naturally occurs.

In FIG. 6, the positive electrode case and the negative electrode case are formed in a U-shaped cross section and in a plane rectangular shape.
0 and the negative electrode 4 are formed in a square shape corresponding to the case shape, and other configurations are the same as the above.

From the above examples, comparing the electrochemical gas sensor according to the present invention shown in FIGS. 1, 3, 4, 5, and 6 with the conventional sensor shown in FIG. The electrochemical gas sensor has a structure in which it is not necessary to take out the lead from the electrolytic solution in order to take out the electric current from the positive electrode and the negative electrode. The complicated work involved in the process of sealing the outlet is eliminated. In addition, since the structure of the sensor itself is extremely simple, it is possible to provide a highly reliable and small electrochemical gas sensor.

[0085]

The electrochemical gas sensor according to the first aspect of the present invention includes a positive electrode case having conductivity, a positive electrode for electrochemically reducing an oxidizing gas provided in the case, a negative electrode, and a positive electrode for the positive electrode. A positive electrode is provided with a diaphragm that restricts the supply of oxidizing gas and an electrolytic solution, and the negative electrode, the diaphragm and the electrolytic solution are arranged in a positive electrode case so that the oxidizing gas can be introduced into the positive electrode through the diaphragm. It is characterized in that the case is sealed.

In the electrochemical gas sensor according to the second invention, a positive electrode for electrochemically reducing an oxidizing gas, a conductive negative electrode case provided with a negative electrode, and a supply amount of the oxidizing gas to the positive electrode are limited. And a electrolytic solution,
The positive electrode, the diaphragm, and the electrolytic solution are disposed in the negative electrode case and the negative electrode case is sealed so that the oxidizing gas can be introduced into the positive electrode through the diaphragm.

An electrochemical gas sensor according to a third aspect of the present invention is a positive electrode case having conductivity, a positive electrode for electrochemically reducing an oxidizing gas provided in the case, and a negative electrode having conductivity provided with a negative electrode. A case, a diaphragm for limiting the amount of oxidizing gas supplied to the positive electrode, and an electrolytic solution are provided, and the diaphragm is arranged on the positive electrode or the negative electrode case so that the oxidizing gas can be introduced into the positive electrode through the diaphragm. In addition, the positive electrode case and the negative electrode case are sealed.

An electrochemical gas sensor according to a fourth aspect of the present invention comprises a negative electrode case having conductivity, a negative electrode electrochemically oxidizing a reducing gas provided in the case, and a positive electrode.
The positive electrode, the diaphragm, and the electrolytic solution are arranged in a negative electrode case so that a reducing gas is supplied to the negative electrode and an electrolytic solution is provided so that the reducing gas can be introduced into the negative electrode through the diaphragm. And the negative electrode case is sealed.

An electrochemical gas sensor according to a fifth aspect of the present invention limits a supply amount of reducing gas to the negative electrode, which has a negative electrode that electrochemically oxidizes a reducing gas, a conductive positive electrode case provided with the positive electrode, and the negative electrode. And a electrolytic solution,
The positive electrode, the diaphragm, and the electrolytic solution are arranged in the positive electrode case and the positive electrode case is sealed so that the reducing gas can be introduced into the negative electrode through the diaphragm.

An electrochemical gas sensor according to a sixth aspect of the present invention is a conductive negative electrode case, a negative electrode that electrochemically oxidizes a reducing gas provided in the case, and a positive electrode having a positive electrode. A case, a diaphragm for limiting the amount of reducing gas supplied to the negative electrode, and an electrolytic solution are provided, and the diaphragm is arranged on the positive electrode or the negative electrode case so that the reducing gas can be introduced into the negative electrode through the diaphragm. In addition, the positive electrode case and the negative electrode case are sealed.

By the electrochemical gas sensor according to the present invention, it is possible to provide an electrochemical gas sensor which can be miniaturized without the need to take out leads from the inside of the electrolytic solution to the outside as in the conventional case.

Further, it becomes possible to manufacture an inexpensive gas sensor and the manufacturing is easy, which greatly contributes to the industry.

[Brief description of drawings]

FIG. 1 is a sectional structural view of an electrochemical oxygen sensor according to an embodiment of the present invention.

FIG. 2 is a sectional structural view of a conventional galvanic cell type oxygen sensor.

FIG. 3 is a sectional structural view of an electrochemical oxygen sensor according to another embodiment of the present invention.

FIG. 4 is a sectional structural view of an electrochemical hydrogen sensor according to another embodiment of the present invention.

FIG. 5 is an explanatory diagram of an electrochemical oxygen sensor according to another embodiment of the present invention.

FIG. 6 is an explanatory diagram of an electrochemical oxygen sensor according to another embodiment of the present invention.

[Explanation of symbols]

 1 Positive electrode 2 Positive electrode case 3 Oxygen introduction hole 4 Lead 5 Titanium 6 Negative electrode 7 Septum 8 Electrolyte 9 Gasket 10 Positive lead wire 11 Negative lead wire 12 Negative electrode 13 ABS resin container 14 Epoxy resin 15 Lead extraction mouth

Claims (22)

[Claims] 1. A positive electrode case having conductivity, a positive electrode provided in the case for electrochemically reducing an oxidizing gas, a negative electrode, and a diaphragm for limiting the amount of the oxidizing gas supplied to the positive electrode. An electrolytic solution is provided, and the negative electrode, the diaphragm and the electrolytic solution are disposed in the positive electrode case and the positive electrode case is sealed so that the oxidizing gas can be introduced into the positive electrode through the diaphragm. Electrochemical gas sensor. 2. A positive electrode for electrochemically reducing an oxidizing gas, a negative electrode case having a conductive property provided with a negative electrode, a diaphragm for limiting the amount of oxidizing gas supplied to the positive electrode, and an electrolytic solution. An electrochemical gas sensor characterized in that a positive electrode, a diaphragm and an electrolytic solution are arranged in a negative electrode case and a negative electrode case is sealed so that an oxidizing gas can be introduced into the positive electrode through a diaphragm. 3. A positive electrode case having conductivity, a positive electrode provided in the case for electrochemically reducing an oxidizing gas, a negative electrode case having conductivity provided with a negative electrode, and an oxidizing property for the positive electrode. A diaphragm for limiting the gas supply amount and an electrolytic solution are provided, and the diaphragm is arranged in the positive electrode case or the negative electrode case and the positive electrode case and the negative electrode case so that the oxidizing gas can be introduced into the positive electrode through the diaphragm. An electrochemical gas sensor, characterized in that the gas is sealed. 4. A negative electrode case having conductivity, a negative electrode provided in the case for electrochemically oxidizing a reducing gas, a positive electrode, and a diaphragm for limiting a reducing gas supply amount to the negative electrode. An electrolytic solution is provided, and the positive electrode, the diaphragm, and the electrolytic solution are arranged in the negative electrode case and the negative electrode case is sealed so that the reducing gas can be introduced into the negative electrode through the diaphragm. Electrochemical gas sensor. 5. A negative electrode that electrochemically oxidizes a reducing gas, a conductive positive electrode case provided with a positive electrode, a diaphragm that limits the amount of reducing gas supplied to the negative electrode, and an electrolytic solution. An electrochemical gas sensor characterized in that a positive electrode, a diaphragm and an electrolytic solution are arranged in a positive electrode case and the positive electrode case is sealed so that a reducing gas can be introduced into the negative electrode through the diaphragm. 6. A negative electrode case having conductivity, a negative electrode electrochemically oxidizing a reducing gas provided in the case, a positive electrode case having conductivity provided with a positive electrode, and a reducing property to the negative electrode. A diaphragm for limiting the gas supply amount and an electrolytic solution are provided, and the diaphragm is arranged in the positive electrode case or the negative electrode case and the positive electrode case and the negative electrode case so that the reducing gas can be introduced into the negative electrode through the diaphragm. An electrochemical gas sensor, characterized in that the gas is sealed. 7. The electrochemical gas sensor according to claim 1, wherein the positive electrode is platinum, gold or an alloy of platinum sputtered or vapor-deposited or sputtered on a corrosion resistant metal. 8. The positive electrode is platinum, gold or an alloy of platinum, which is sputtered or vapor-deposited on the metal surface side of a toroidal corrosion-resistant metal having a diaphragm or a diaphragm attached thereto. The electrochemical gas sensor according to 1, 2 or 3. 9. The electrochemical gas sensor according to claim 4, wherein the negative electrode is platinum or gold plated with a corrosion resistant metal. 10. The negative electrode is platinum, gold or an alloy of platinum, which is sputtered or vapor-deposited on the metal surface side of a doughnut-shaped corrosion-resistant metal having a diaphragm or a diaphragm attached thereto. The electrochemical gas sensor described in 4, 5, or 6. 11. The electrochemical gas sensor according to claim 1, wherein the positive electrode case is sealed with the negative electrode by a diaphragm or a diaphragm. 12. The electrochemical gas sensor according to claim 2 or 4, wherein the negative electrode case is sealed with the positive electrode by a diaphragm or a diaphragm. 13. The electrochemical gas sensor according to claim 1, wherein the negative electrode or the positive electrode case is sealed with a sealing material made of a resin or a corrosion resistant metal. 14. The negative electrode is provided with an oxidizing gas introduction hole and is provided with a diaphragm for sealing the introduction hole, wherein the negative electrode has a lead surface facing downward and is located in the introduction hole. The electrochemical gas sensor according to claim 1, wherein the positive electrode case and the negative electrode are caulked and sealed so that the positive electrode case and the positive electrode are in contact with each other. 15. The positive electrode is provided with a reducing gas introduction hole and a diaphragm for sealing the introduction hole is attached, and the positive electrode has a lead dioxide surface facing downward and is located in the introduction hole. The electrochemical gas sensor according to claim 4, 9 or 12, wherein the diaphragm and the negative electrode are arranged in contact with each other in the negative electrode case, and the negative electrode case and the positive electrode are caulked and sealed. 16. An oxidizing gas introducing hole is formed in the negative electrode case and the negative electrode provided in the case, and a diaphragm for sealing the introducing hole is provided on the outer surface of the case or between the case and the negative electrode. The positive electrode case and the negative electrode case are caulked and sealed so that the lead surface of the negative electrode faces downward and the diaphragm located in the introduction hole and the positive electrode are in contact with each other. ,
The electrochemical gas sensor according to 7, 11 or 12. 17. A reducing gas introduction hole is formed in the positive electrode case and the positive electrode provided in the case, and a diaphragm for sealing the introduction hole is provided on the outer surface of the case or between the case and the positive electrode. The negative electrode case and the positive electrode are caulked and sealed so that the lead dioxide surface of the positive electrode faces downward and the diaphragm positioned in the introduction hole contacts the negative electrode. 13. An electrochemical gas sensor according to items 6, 9, 11 or 12. 18. The negative electrode is made of lead, a clad material of lead and a corrosion resistant metal, or lead is plated on a corrosion resistant metal, and the oxidizing gas is oxygen, ozone, or chlorine. Claims 1, 2, 3, 7, 8, 11, 12, 1
3. An electrochemical gas sensor according to 3, 14 or 16. 19. The positive electrode is a cladding material of lead dioxide, lead oxide and a corrosion resistant metal, or lead dioxide plated on a corrosion resistant metal, and the reducing gas is hydrogen or carbon monoxide. Claims 4, 5, 6, 9, characterized in that
The electrochemical gas sensor according to 10, 11, 12, 13, 15 or 17. 20. The positive electrode is formed on the positive electrode case by plating, vapor deposition or sputtering, and the positive electrode case is formed by plating.
Alternatively, the electrochemical gas sensor according to item 18. 21. The negative electrode is formed on the negative electrode case by plating, vapor deposition or sputtering, and the negative electrode case is characterized in that:
Alternatively, the electrochemical gas sensor according to Item 19. 22. The electrolytic solution is gelled, claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 1.
0, 11, 12, 13, 14, 15, 16, 17, 1
The electrochemical gas sensor according to 8, 19, 20, 21.