JPH11190719A - Gas sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and suitably replace a sensor element or a catalytic unit by easily assembling in the case of manufacturing a gas sensor device. SOLUTION: The gas sensor device for detecting a specific oxidizing component contained in a flue gas in contact with an oxidizing catalyst by using a solid electrolyte comprises a solid electrolytic base material 12, a sensor element 10 in contact with the flue gas to generate an electromotive force, a catalytic unit 30 having the oxidizing catalyst, a cylindrical case 32 in contact of a sensing surface of the element 10 with the flue gas to contain the element 10 and the unit 30, and a cylindrical spacer 34 contained at both sides or the like of the element 10 in the case 32 to dispose the element 10 and the unit 30 at predetermined positions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas sensor device, and more particularly, to a gas sensor device for measuring the concentration of a specific oxidizing component in flue gas brought into contact with an oxidation catalyst.

[0002]

2. Description of the Related Art Online determination of the concentration of SO _X , NO _X , CO _X in flue gas discharged from a boiler or an engine is only possible to grasp the current state of the boiler or the engine. It is also necessary for the surrounding environment management. Here, for example, a gas sensor device shown in FIG. 5 is used as a gas sensor device for detecting the concentration of SO ₃ in a gas. A sensor element which is a gas sensor of the gas sensor device shown in FIG.
No. 6 and the like can be used.
That is, a detection electrode composed of a mixture 14 of a sulfate containing silver sulfate and a silver electrode 16 is provided on one surface of a fixed electrolyte substrate 12 such as yttria-stabilized zirconia ceramics that comes into contact with a gas (flue gas) to be detected. 13 is provided, and a reference electrode 18 made of platinum is provided on the other side of the base material 12 that comes into contact with air.

The reference electrode 18 of such a sensor element 10 is
A cylindrical body 20 into which air is sent in the direction of arrow B is bonded to the base material 12 by fused glass so that the cylindrical body 20 is always in contact with air while being isolated from the detection gas containing SO ₃ .
In addition, a so-called sealed type gas sensor device provided so as to isolate the flue gas from the air as described above, so that the flue gas comes into contact with both the detection electrode 13 and the reference electrode 18. There is also a so-called throw-in type gas sensor device. Even with this throw-in type gas sensor device,
As described above, when the detection electrode 13 (sub-electrode) is composed of the sulfate mixture 14 and the silver electrode 16 and detects the concentration of SO _{3 in} the gas, the SO ₃ concentration (specific oxidation component Concentration) can be suitably detected. This is because the oxygen partial pressure becomes equal on both sides of the detection electrode 13 and the reference electrode 18 and is not affected by the partial pressure. On the other hand, the action of the sub-electrode (detection electrode 13) makes it possible to reduce the electromotive force as described below. By what happens.

Here, the principle of detecting the gas concentration (for example, the concentration of SO ₃ ) of the gas sensor device will be described. When a detection gas containing SO ₃ comes into contact with the detection electrode 13 of the sensor element 10, a reaction shown in the following [Formula 1] is caused to detect SO ₃ .

Embedded image Among the reactions, the reaction shown in the following [Chemical Formula 2] is induced at the silver electrode 16, and the reaction of the [Chemical Formula 3] is induced in the mixture 14. Further, the reaction of [Chemical Formula 4] is also caused in the substrate 12.

Embedded image

Embedded image

Embedded image

As described above, the sensor element 10 shown in FIG. 5 only detects SO ₃ in the detection gas.
A component having a lower oxidation state than SO ₃ such as SO ₂ (hereinafter sometimes referred to as a lower oxidation component) cannot be detected. For this reason, after oxidizing a lower oxidation component such as SO ₂ to SO ₃ ,
It is necessary to measure the concentration of SO ₃ by the sensor element 10. For this reason, in the gas sensor device shown in FIG.
A platinum wire 100 or the like is inserted as an oxidation catalyst into an introduction pipe 22 for introducing a flue gas containing a lower oxidation component such as O ₂ into the sensor element 10 from the direction of arrow A, and a lower oxidation component such as SO ₂ is inserted. Is oxidized to SO ₃ .

According to the gas sensor device shown in FIG. 5, the sulfur component in the flue gas can be converted to SO ₃ and accurately measured. When a carbonate is used as a component to be mixed with the mixture 14, CO _X can be measured, and when a nitrate is used, N 2 can be measured.
The O _X can be measured. Thus, SO _X , NO _X , CO
To measure any of _X , a lower oxidizing component such as SO ₂ component contained in the flue gas is brought into contact with an oxidation catalyst such as platinum and a component having a high oxidation state such as SO ₃ (hereinafter, referred to as “SO ₃ component”). (Sometimes referred to as higher oxidation components).

Further, the flue gas contains soot, and the soot adheres to the detection surface of the gas sensor, such as the detection electrode 13, and a reaction different from the above-described reaction in the gas sensor is caused. Lines and the like may fluctuate. In order to solve this problem, a filter for removing soot is provided between the flue gas inlet and the sensor element 10 to prevent soot from adhering to the detection surface of the sensor element 10. Thereby, detection accuracy can be improved.

[0008]

However, conventionally, when a sensor element, which is a ceramic gas sensor, or a member (catalyst unit) having an oxidation catalyst function is held (fixed), fused glass or the like is attached to a ceramic tube or the like. Using an inorganic adhesive. This method has a problem that when one of the sensor element and the catalyst unit stops functioning, it is impossible to partially replace the sensor element or the catalyst unit. For example, even if the function of the sensor element is normal,
When the effectiveness of the oxidation catalyst has died, the entire gas sensor device has to be replaced. Further, when the gas sensor device is manufactured through the bonding process using the inorganic adhesive as described above, there is a problem that a high-temperature heating process is required and the assembly cannot be easily performed.

The reason why the sensor element is adhered to the ceramic tube is that the sensor element itself has a solid electrolyte base made of ceramics. Since the gas sensor device is used in a high-temperature atmosphere, the bonded state cannot be maintained properly unless the gas sensor devices have the same thermal expansion coefficient. For example, conventionally, when the base material of the fixed electrolyte of the sensor element is formed of yttria-stabilized zirconia ceramics, a ceramic tube for fixing the sensor element is also formed of a stabilized zirconia-based ceramic.

It is an object of the present invention to provide a gas sensor device which can be easily assembled at the time of manufacturing and can easily and appropriately replace a sensor element and a catalyst unit.

[0011]

To achieve the above object, the present invention has the following arrangement. That is, the present invention
A gas sensor device for detecting a specific oxidizing component contained in a flue gas brought into contact with an oxidation catalyst using a solid electrolyte, comprising a solid electrolyte base material, and generating an electromotive force by contacting the flue gas. A sensor element, a catalyst unit including the oxidation catalyst, a case accommodating the sensor element and the catalyst unit, such that the flue gas can contact a detection surface of the sensor element, and a sensor element in the case. A spacer that is housed on both sides and the like and that arranges the sensor element and the catalyst unit at predetermined positions.

[0012] Further, the provision of the holding means for holding the sensor element and the catalyst unit in the case in a replaceable manner makes it possible to easily and appropriately exchange the sensor element and the catalyst unit.

In addition, a soot removal filter for allowing the flue gas from which soot has been removed to come into contact with the detection surface of the sensor element is provided in the case from the flue gas inlet of the case to the sensor element. By providing an intervening gas, a specific oxidizing component in the flue gas can be accurately measured.

The case also has a function of a heater for heating the solid electrolyte or the like to a predetermined temperature,
A gas sensor device having a predetermined detection function can be miniaturized (compact).

Further, the sensor element has a detection electrode provided on one surface of a solid electrolyte substrate and a reference electrode provided on the other surface of the substrate. Thus, it can be manufactured easily, compactly and easily.

Further, the base material of the solid electrolyte is a disk shape, the catalyst unit is a cylindrical shape having a platinum net, and the filter is formed in a disk shape;
Since the case is cylindrical and the spacer is cylindrical, each member can be suitably manufactured, and each member can be easily and suitably incorporated.

Further, by using a porous ceramic body having platinum and / or palladium, which is an oxidation catalyst, supported on the surface and inside thereof as a filter, the SO ₂ component and the like can be removed while removing soot in the flue gas. Can be efficiently oxidized. Thereby, detection accuracy can be improved.

Further, the sensor element is composed of SO _X , N
O _X, or a plurality of detection regions for detecting a different gas of CO _X, etc., to detect two or more gases, or,
In the case, a plurality of the sensor elements for detecting different gases such as SO _X , NO _X , or CO _X are housed, and by detecting two or more types of gases, a composite gas in which a plurality of gases are mixed is formed. It can be suitably used as a corresponding gas sensor device.

[0019]

(First Embodiment) FIG. 1 schematically shows an example (first embodiment) of a gas sensor device according to the present invention. The gas sensor device of the first embodiment is provided with a sensor element 10 for measuring the concentration of SO _{3 in} flue gas introduced from the direction of arrow A via an introduction pipe. The sensor element 10 includes a mixture 1 of a sulfate containing silver sulfate on one surface of a substrate 12 made of yttria-stabilized zirconia ceramics, which is a solid electrolyte material, in contact with flue gas.
A detection electrode 13 comprising a silver electrode 4 and a silver electrode 16 is provided, and a reference electrode 18 made of platinum is provided on the other side of the substrate 12 which comes into contact with air. As described in the section of the related art, an electromotive force is generated by contacting SO ₃ in flue gas. Further, the solid electrolyte substrate 12 of the present embodiment is:
It is formed in a disk shape.

Reference numeral 30 denotes a catalyst unit provided with an oxidation catalyst. For example, the catalyst unit 30 is formed in a tubular shape having a mesh (platinum mesh) made of platinum, which is an oxidation catalyst, or by forming a stainless steel into a so-called channel structure and applying platinum plating. An oxidizing medium which is incorporated in a cylinder can be used. The catalyst unit provided with a platinum mesh may be formed by bonding a platinum mesh to each end face of a ring-shaped cylinder, or by incorporating a platinum mesh inside the ring-shaped cylinder.

As will be described later, platinum and / or palladium, which is an oxidation catalyst, is carried on the surface and inside of a filter 24 in which a porous ceramic body is formed in a disk shape, so that the filter function is also used. It is also possible to make the catalyst unit 30 perform. Thus, as an oxidation catalyst, to be able to contact flue gas efficiently,
What is necessary is just to use the structure which can obtain a large surface area, for example, the honeycomb structure can also be used suitably. Then, by incorporating the oxidation catalyst into a cylinder having high corrosion resistance such as ceramics, a suitable catalyst unit 30 can be formed.

Reference numeral 32 denotes a cylindrical case, and the sensor element 10
This is a pipe-shaped case that houses the catalyst unit 30 and the catalyst unit 30. The cylindrical case 32 is formed to have a slightly larger inner diameter than the outer diameter of each storage member so that storage members such as the sensor element 10 and the catalyst unit 30 are stored. Cylindrical case 3
2 suitably stores the sensor element 10 and the catalyst unit 30 so that the flue gas can contact the detection surface of the sensor element 10. The cylindrical case 32 may be formed of ceramics such as yttria-stabilized zirconia ceramics, or may be formed of a metal having good corrosion resistance. In the present invention, since the sensor element 10 and the catalyst unit 30 are assembled without bonding, a difference in the coefficient of thermal expansion is allowed as compared with the case where the sensor element 10 is fixed by bonding.

Numeral 34 denotes a cylindrical spacer, and the sensor element 1
In the cylindrical case 32, the sensor element 10 and the catalyst unit 30 are housed on both sides of the catalyst unit 30 so that the zero and the catalyst unit 30 are arranged at predetermined positions in the cylindrical case 32. That is, in the present embodiment, the first cylindrical spacer 34 sandwiched between the fixing means 36 at one end (the end of the flue gas inlet) of the cylindrical case 32 and the catalyst unit 30, A second cylindrical spacer 34 interposed between the sensor elements 10 and a third cylindrical spacer 34 interposed between the fixing means 36 at the other end of the cylindrical case 32 and the sensor element 10 Is used. These tubular spacers 34 may be formed of ceramics (insulator) such as zirconia or alumina.

The sensor element 10 and the catalyst unit 30
Is not limited to this embodiment. For example, a spacer in which the cylindrical spacer 34 and the holding piece of the fixing means 36 are integrated is used. You may. In addition, the spacer is not limited to a cylindrical shape such as a cylinder, but may be appropriately spaced apart from each other and may be suitably held (fixed). It is also possible to use a cut-out form so as not to interfere. However,
The catalyst unit 30 has a cylindrical shape, the sensor element 10 has a disk shape, the case has a cylindrical shape, and the spacer has a cylindrical shape. It can be suitably formed and is advantageous in terms of functions such as strength and homogeneity, and furthermore, each member can be manufactured easily and accurately with good accuracy, and each member can be easily and accurately assembled with good accuracy. This has an advantageous effect in that respect.

The holding means 36 is provided at both ends of the cylindrical case, and holds the sensor element 10 and the catalyst unit 30 in the cylindrical case 32 in a replaceable manner. In this embodiment,
The first cylindrical spacer 34, the catalyst unit 30, the second cylindrical spacer 34, the sensor element 10, and the third cylindrical spacer 34 are inserted in series in the cylindrical case 32. It is housed and held in a state of being pinched by a pair of holding means 36, 36. In this embodiment, the case where the equivalent holding means 36 is formed at both ends of the cylindrical case 32 has been described. However, the present invention is not limited to this.
May simply have a stopper function. For example, a flange-shaped edge may be formed at one end of the cylindrical case 32 toward the inner peripheral side.

As described above, in the first embodiment, the sensor element 10, the catalyst unit 30 and the like are not fixed to the ceramic tube corresponding to the cylindrical spacer 34 with an adhesive or the like, and the inner diameter is substantially the same as the outer shape of the conventional ceramic tube. Into the tubular case 32, which is a pipe-shaped case having
It is fixed in the state held by. Therefore, it can be easily incorporated in manufacturing. Further, according to the above gas sensor device, the sensor element 10, the catalyst unit 30, and the like are simply housed in the cylindrical case 32, and can be easily disassembled. Therefore, the sensor element 10 and the catalyst unit 30
Can be easily exchanged individually. Therefore, maintenance can be suitably performed,
Cost can be reduced. On the other hand, conventionally, when a part of the sensor element 10 or the catalyst unit 30 has lost its function,
The entire gas sensor device needs to be replaced, which is uneconomical. Note that the distance between the sensor element 10 and the catalyst unit 30 can be appropriately adjusted by adjusting the length of the ceramic tube used as the cylindrical spacer 34.

(Second Embodiment) The first embodiment is a so-called sealed type sensor, but the present invention relates to a so-called throw-in type in which a flue gas as shown in FIG. 2 is actively leaked. The present invention can also be suitably applied to a sensor (second embodiment). In order to leak the flue gas and expose the flue gas to the reference electrode 18 as well, the solid electrolyte base 12 is cut out or a through hole 12a is formed in the solid electrolyte base 12 as shown in FIG. You may. Since the flue gas is brought into contact with both the detection surfaces of the detection electrode 13 and the reference electrode 18 of the sensor element 10, as described in the section of the related art, the influence of the oxygen partial pressure is eliminated, and the concentration of the specific gas is not changed. Accurate detection is possible. In addition, since the sensor element 10 has the through-hole 12a, the flow of the flue gas in the cylindrical case 32 is improved, and the speed of detecting the gas of the sensor (reaction speed) is improved. The other configuration is the same as that of the first embodiment, and the description is omitted.

Further, in order to make the flue gas positively contact the detection surfaces of the detection electrode 13 and the reference electrode 18 of the sensor element 10, both detection surfaces should be parallel to the axis of the cylindrical case 32. It is also possible to dispose a solid electrolyte base material 12 on the substrate. Further, it is also possible to form the detection electrode 13 and the reference electrode 18 only on one side of the solid electrolyte substrate 12 instead of forming them on the front and back of the substrate 12, and to make the flue gas positively contact both electrodes.

(Third Embodiment) Next, an embodiment (third embodiment) of another gas sensor device will be described with reference to FIG. This embodiment is different from the first embodiment and the second embodiment in that
The basic configuration is the same, but differs in that a soot removal filter 24, a catalyst unit 30 having a filter function, and a cylindrical case 32 having a heater function are provided. First, the smoke removing filter 24 is formed in a disk shape, and the smoke of the cylindrical case 32 is inserted into the cylindrical case 32 so that the flue gas from which the smoke has been removed is brought into contact with the detection surface of the sensor element 10. It is housed (provided) between the passage gas inlet and the sensor element. In the present embodiment (third embodiment), two filters 24 are stacked and housed on each of the detection surfaces of the detection electrode 13 and the reference electrode 18. That is, since the gas sensor device of the third embodiment is used in a flue, a filter is provided on both the detection electrode 13 side and the reference electrode 18 side of the sensor element 10, and the soot on both sides is suitably removed. There is.

At least one of the soot removal filters 24 disposed on the detection surface (detection electrode 13) side on which the sub-electrode of the sensor element 10 is formed becomes a catalyst unit 30 having a filter function. ing. In the present embodiment, the filter 24 closest to the detection electrode 13 is the catalyst unit 30. This catalyst unit 30
An oxidation catalyst, platinum and / or palladium, is provided on the surface of a porous ceramic body (for example, porous brick) and inside thereof. By using this catalyst unit 30, the contact area between the flue gas and the platinum catalyst can be increased while removing the soot in the flue gas introduced from the introduction pipe or the like, and contained in the flue gas. The lower oxidized component such as the SO ₂ component can be oxidized sufficiently efficiently to the higher oxidized component such as the SO ₃ component. Therefore, this SO
According ₃ to the sensor element 10 for detecting the sensor element 10
Can prevent soot from adhering to the detection electrode 13 and accurately measure the sulfur component contained in the flue gas as SO ₃ .

The catalyst unit 30 can be obtained by immersing a porous brick in a dispersion obtained by dispersing and diluting a platinum paste in a solvent such as acetone, and then performing a heat treatment for removing the solvent and the like. Note that hexachloroplatinic acid may be used instead of the platinum paste, and the catalyst unit 30 can also be obtained by performing a heat treatment for removing a solvent or the like attached to the porous brick.

Further, the catalyst unit 30 is not limited to the embodiment of the third embodiment, but is formed on one surface side of the solid electrolyte substrate 12 on which the detection electrodes 13 are provided, so as not to interfere with the detection electrodes 13. Thus, it may be possible to make contact.
Alternatively, by forming the catalyst unit 30 in which the cylindrical spacer 34 is integrated, the catalyst unit 30 may be directly pressed against one surface of the solid electrolyte base material 12 on the side of the detection electrode 13. In these cases, the sensor element 1
A part of the catalyst unit 30 also serves as a spacer between the zero and the catalyst unit 30, and a specially independent spacer is not required, but a spacer exists substantially. The formation of the catalyst unit 30 in this manner may be applied to the one described in the first embodiment.

Next, the holding means 36 of the third embodiment will be described. Reference numeral 38 denotes a fixed angle, which is formed in an L-shape and is fixed to an end face of the cylindrical case 32. In this embodiment, a plurality of cylindrical cases 32 are arranged and fixed to both end surfaces. Reference numeral 37 denotes an L-shaped holding piece,
It is fixed to the fixed angle 38 by the screw 39. The holding piece 37 sandwiches the sensor element 10, which is a storage member housed in the cylindrical case 32, the cylindrical spacer 34 inserted on both sides thereof, the filter 24, and the catalyst unit 30, so that adjacent storage members are separated from each other. They are fixed in a state where they are pressed against each other. If the screws 39 are loosened and the holding pieces 37 are removed from the state in which the storage members are held in this manner, the storage members can be disassembled in a replaceable manner. Therefore, when the storage member such as the sensor element 10 breaks down, it can be replaced appropriately and easily.

Next, the heater function of the cylindrical case 32 will be described. The cylindrical case 32 is an electric furnace (ring heater) formed in a ring shape, and has a function of a heater for heating the sensor element 10 to a predetermined temperature.
This is sufficient so that the ionic conductivity (oxygen conductivity) of the solid electrolyte base material 12 such as yttria-stabilized zirconia ceramics is sufficient and the ionic conductivity of sulfate and the like as the sub-electrode is sufficient. Response temperature (for example, about 6
(00 ° C.) to maintain the temperature. A thermocouple 40 monitors the temperature of the ring heater. Since the cylindrical case 32 has the heater function as described above, the size of the gas sensor device having the predetermined detection function can be reduced. Reference numeral 42 denotes a lead wire drawn out from each electrode, which is provided with a platinum wire or the like and is connected to the electrode lead wire 44 (connection portion omitted), and a detection signal based on electromotive force is output to the outside by this lead wire. Is done. 46 is a ground wire.

In the sensor element 10 shown in the above embodiment, the silver electrode 16 is in direct contact with the flue gas,
When the concentration of SO _{3 and} the like are measured by covering the silver electrode 16 forming the third electrode 3 with a platinum film, N in the flue gas is measured.
The impact of O _X can be prevented. The sensor element 10 described above is a gas sensor that measures the concentration of SO _{3 in} flue gas using a sulfate containing silver sulfate for the mixture 14. When used, the gas sensor can measure CO _X, and when nitrate is used, the gas sensor can measure NO _X. Further, as the oxidation catalyst carried on the filter 24,
A palladium catalyst may be used in place of the platinum catalyst, or a mixture of a platinum catalyst and a palladium catalyst may be used.

In the above embodiment, one sensor element
The case where a kind of gas is detected by the child 10 has been described.
However, the present invention is not limited to this. For example, one sensor element
But SO _X, NO_XOr CO_XDetect different gases such as
To detect two or more types of gases
It may be a composite gas sensor element. Even better
In the case, SO_X, NO_XOr CO_XEtc.
A plurality of the sensor elements for detecting different gases are housed.
Alternatively, two or more gases may be detected. First
In a sealed gas sensor device such as the embodiment,
The flue gas passes through each sensor element
Can be stored in parallel so that it can touch the sensing surface of
No. FIG. 4 shows a throw-in type gas sensor device.
As described above, since the flue gas can flow through the through holes 12a and the like,
A plurality of individually formed sensor elements 10A and 10B
As if they were stacked in series via a pacer (cylindrical spacer 34)
Alternatively, it may be stored in a case (tubular case 32).

In the above description, yttria-stabilized zirconia ceramics is used as a solid electrolyte, and sulfate, carbonate,
Although the target was a gas sensor device using nitrate as a molten salt,
The present invention is not limited to this, and it is needless to say that the present invention can be applied to a gas sensor device having another solid electrolyte or the like as a component. For example, as the solid electrolyte, Na
+ Β-alumina or NASICON (Na-super ionic
and sodium salt (Na ₂ CO ₃ ), sodium sulfate (Na ₂ SO ₄ ), and sodium nitrate (NaNO ₃ ) as a molten salt constituting the sub-electrode. According to this, CO _X , SO _X , and NO _X can be detected according to the type of the molten salt. Further, as other solid electrolytes, a fluoride ion conductor, an Ag + and Cu + conductor, a Li + conductor, and a proton conductor can be used. Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. .

[0038]

According to the gas sensor device of the present invention,
In the case, the sensor element and the catalyst unit can be housed in a predetermined position by a spacer so that the flue gas can contact the detection surface of the sensor element. Therefore, according to the present invention, when a part of a storage member such as a sensor element or a catalyst unit breaks down, it can be disassembled and easily and appropriately replaced, and can be easily assembled when manufacturing a gas sensor device. It has a significant effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a first embodiment of a gas sensor device according to the present invention.

FIG. 2 is a schematic diagram for explaining a second embodiment of the gas sensor device according to the present invention.

FIG. 3 is a sectional view illustrating a third embodiment of the gas sensor device according to the present invention.

FIG. 4 is a cross-sectional view for explaining another embodiment of the gas sensor device according to the present invention.

FIG. 5 is a schematic diagram for explaining a conventional gas sensor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sensor element 12 Solid electrolyte base material 13 Detection electrode 14 Mixture 16 Silver electrode 18 Reference electrode 24 Filter 30 Catalyst unit 32 Cylindrical case 34 Cylindrical spacer 36 Holding means

Claims (12)

[Claims] 1. A gas sensor device for detecting a specific oxidizing component contained in a flue gas brought into contact with an oxidation catalyst using a solid electrolyte, comprising: a solid electrolyte base material; A sensor element that generates an electromotive force, a catalyst unit including the oxidation catalyst, and the flue gas can be brought into contact with a detection surface of the sensor element.
A case that houses the sensor element and the catalyst unit; and a spacer that is housed on both sides of the sensor element in the case and arranges the sensor element and the catalyst unit at predetermined positions. Gas sensor device. 2. The gas sensor device according to claim 1, further comprising holding means for holding the sensor element and the catalyst unit in a case in a replaceable manner. 3. A filter for removing soot from which flue gas from which soot has been removed can be brought into contact with the detection surface of the sensor element. 1 or 2 characterized by being provided between
The gas sensor device according to claim 1. 4. The gas sensor device according to claim 1, wherein the case has a function of a heater for heating the solid electrolyte or the like to a predetermined temperature. 5. The sensor element according to claim 1, wherein a sensing electrode for contacting the flue gas is provided on one surface side of the solid electrolyte base material, and a reference electrode is provided on the other surface side of the base material. The gas sensor device according to claim 1, 2, 3, or 4, wherein 6. The gas sensor device according to claim 1, wherein the substrate of the solid electrolyte has a disk shape. 7. The catalyst unit according to claim 1, wherein the catalyst unit has a cylindrical shape provided with a platinum net.
Or the gas sensor device according to 6. 8. The filter according to claim 2, wherein the filter is a porous ceramic body formed in a disk shape and carrying platinum and / or palladium as an oxidation catalyst on the surface and inside thereof. The gas sensor device according to 3, 4, 5, 6, or 7. 9. The gas sensor device according to claim 1, wherein the case has a cylindrical shape. 10. The spacer according to claim 1, wherein the spacer has a cylindrical shape.
The gas sensor device according to claim 1. 11. The sensor element according to claim 1, wherein said sensor element comprises SO _X , NO _X ,
Or a plurality of detection regions for detecting a different gas of CO _X, etc., claim and detecting two or more gases 1,2,3,4,5,6,7,8,9 Or the gas sensor device according to 10. 12. A plurality of the sensor elements for detecting different gases such as SO _X , NO _X , and CO _X are housed in the case, and two or more kinds of gases are detected. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
Or the gas sensor device according to 11.