JP2018141800A - Gas detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas detector which is hardly influenced by various disturbing components, is excellent in responsiveness of gas to be detected, and is excellent in productivity.SOLUTION: A gas detector including a gas detection element 10 having a gas sensitive part 12 that comes in contact with gas to be detected comprises dual casings 51, 52 for storing the gas detection part 10, therein the outer casing 51 of the dual casings comprises a gas introduction port 20 for introducing the gas to be detected; and a first absorption part 31 for absorbing disturbing components, and the inner casing 52 of the dual casings comprises: a decomposition catalytic part 34 for decomposing the disturbing components; and a second absorption part 32 for absorbing the disturbing components in this order in a direction in which the gas to be detected is introduced.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a gas detector including a gas detection element having a gas sensitive portion that comes into contact with a gas to be detected.

  In Patent Document 1, an adsorption filter using activated carbon, zeolite, silica gel, a plastic gas-selective permeable membrane, or the like is provided to absorb miscellaneous gases such as water vapor, ethanol, or trichrene, and miscellaneous gas detection elements. A gas sensor that can mitigate the effects of gas is disclosed.

  Patent Document 2 discloses a gas sensor in which a disturbing component inflow restricting means is provided between a removing means for removing a disturbing component of a gas to be detected and a gas sensitive part. The interference component inflow restricting means can alleviate the influence when the disturbing component is absorbed and released from the removing means due to a change in atmosphere, and can prevent malfunction of the gas sensor when the atmosphere state changes. Specifically, the disturbance component inflow restricting means is disclosed as an inflow restricting plate provided with a pinhole, and the inflow restricting plate is fixed to the housing by a fixing means between the removing means and the gas sensitive part. Has been.

JP 2003-156463 A JP-A-10-197470

  Anti-condensation sprays and hair sprays used at home may contain siloxane compounds. The siloxane compound is an organic polymer having a “Si—O—Si” siloxane bond in the skeleton.

  When the siloxane compound adheres to the gas detection element, the detection sensitivity of the gas detection element decreases, or the gas detection sensitivity increases with respect to gases other than the gas that should be selectively detected, which may cause malfunction. There was. This is because the siloxane compound contained in the gas to be detected reaches the gas detection element as a disturbing component, and the siloxane compound or a decomposition product thereof adheres to the gas detection element, thereby changing the gas detection characteristics of the gas detection element. It is considered a thing.

  Therefore, for example, in a flammable gas sensor, an adsorption filter using activated carbon as an adsorbent is arranged as in Patent Document 1, so that the siloxane compound is adsorbed by the adsorption filter, and the siloxane compound reaches the surface of the gas detection element. Can be prevented.

  When a combustible gas sensor equipped with an adsorption filter is installed in a room such as a kitchen, the adsorption filter adsorbs interfering components such as a siloxane compound floating in the room. For this reason, there is a problem that the adsorption capacity of the adsorption filter tends to be lowered early, and the ability to adsorb the interfering component is lowered.

  Also, in order to improve the durability of combustible gas sensors against interfering components such as siloxane compounds, when the amount of adsorbent introduced into the adsorption filter is greatly increased, or when the area of the gas inlet is reduced, While durability against the disturbing component is improved, responsiveness to the gas to be detected is significantly lowered.

  In addition, when the area of the gas inlet is reduced, in a household kitchen where a disturbing component such as a siloxane compound exists, the disturbing component is adsorbed in a large amount by the adsorbent, particularly during the low temperature and low humidity period, and the inside of the combustible gas sensor housing Easy to hold. In such a situation, if the environment becomes a high temperature and high humidity environment, the detached gas that has desorbed from the adsorbent due to the temperature rise of the adsorbent moves to the gas sensing element side, and the desorbed gas does not exist even though there is no gas to be detected. There was a risk of detecting gas.

  In order to prevent such erroneous detection, the gas sensor described in Patent Document 2 is provided with a disturbing component inflow restricting means (an inflow restricting plate provided with a pinhole) so that the disturbing component moves toward the gas detecting element. Was preventing. The inflow restricting plate is fixed to the housing by a fixing means. If there is a gap between the periphery of the inflow restricting plate and the housing, the disturbing component easily moves to the gas detection element side from the gap. There was a risk of moving. In this case, in order to eliminate the gap between the periphery of the inflow restricting plate and the housing, it is conceivable to seal the periphery of the inflow restricting plate with an adhesive or the like. However, in such a method, the production efficiency of the gas sensor is reduced. There is a problem that the cost is reduced and the cost is increased.

  Accordingly, an object of the present invention is to provide a gas detector that is not easily affected by various interference components, has excellent response of the gas to be detected, and is excellent in productivity.

  In order to achieve the above object, a gas detector according to the present invention is a gas detector including a gas detection element having a gas sensitive portion that comes into contact with a gas to be detected. A double housing for housing the element, and an outer housing on the outside of the double housing includes a gas introduction port for introducing the gas to be detected and a first adsorption portion for absorbing the disturbing component, The inner case inside the heavy case is provided with a decomposition catalyst part for decomposing the disturbing component and a second adsorption part for absorbing the disturbing component in this order from the introduction direction of the gas to be detected.

  According to this configuration, the housing that houses the gas detector has a double housing structure. Therefore, when assembling the gas detector, the space for accommodating the first adsorbing portion, the decomposition catalyst portion, and the second adsorbing portion can be easily formed simply by assembling the outer casing and the inner casing.

In this configuration, the introduced gas introduced into the outer casing from the gas inlet first passes through the first adsorption unit. At this time, if the introduced gas contains an interfering component, it is adsorbed by the first adsorption unit.
When all of the disturbing components are not adsorbed by the first adsorbing portion, the remaining disturbing components reach the decomposition catalyst portion in the inner casing. At this time, the disturbing component introduced into the cracking catalyst part is decomposed by the cracking catalyst part. When all of the interfering components are not decomposed by the decomposition catalyst unit, the remaining interfering components reach the second adsorption unit and are adsorbed by the second adsorption unit.
In this way, since the interference component is decomposed or adsorbed by passing through the decomposition catalyst portion and the second adsorption portion in the inner casing, the interference component reaching the gas detection element is extremely reduced.

  Therefore, the gas detector of the present invention includes the first adsorbing part, the decomposition catalyst part, and the second adsorbing part, so that various disturbing components even when used in a kitchen where various disturbing components such as siloxane compounds exist. Can be made more difficult to be affected.

  Further, as a result of examining the gas responsiveness in Examples described later, it is recognized that the gas detector of the present invention has an excellent gas responsiveness.

  Therefore, the gas detector of the present invention is hardly affected by various interference components, has excellent response of the gas to be detected, and is excellent in productivity.

  The second characteristic configuration of the gas detector according to the present invention is that a limiting means for limiting the inflow of disturbing components is provided between the first adsorption unit and the cracking catalyst unit.

  According to this configuration, when not all of the disturbing components are adsorbed by the first adsorbing portion, the remaining disturbing components reach the decomposition catalyst portion in the inner casing via the restricting means that restricts the inflow of the disturbing components. Can be configured. At this time, for example, the opening area of the restricting means can be set smaller than the opening area of the gas inlet, so that the amount of disturbing components introduced into the cracking catalyst portion can be greatly reduced. Thereby, the disturbing component reaching the gas detection element is extremely reduced.

  A third characteristic configuration of the gas detector according to the present invention is that the inner casing includes a third adsorption portion that absorbs the disturbing component on the upstream side of the cracking catalyst portion.

  According to this configuration, the third adsorption portion is disposed downstream (on the gas detection element side) of the limiting means. In this state, since the third adsorbing part can adsorb the disturbing component via the restricting means, the amount of the disturbing component introduced into the cracking catalyst part disposed downstream of the third adsorbing part is greatly reduced. can do. Thereby, the disturbing component reaching the gas detection element is extremely reduced.

  A fourth characteristic configuration of the gas detector according to the present invention is that the second adsorbing portion and the third adsorbing portion are each formed of a solid acid catalyst.

  If the second adsorbing part and the third adsorbing part having the components of this configuration are used, the interfering component can be adsorbed.

  A fifth characteristic configuration of the gas detector according to the present invention is that the cracking catalyst portion is formed of a carbon-based material supporting a noble metal.

  If the decomposition catalyst portion having the components of this configuration is used, the disturbing components can be decomposed.

  A sixth characteristic configuration of the gas detector according to the present invention is that the first adsorption part is formed of any one of activated carbon, carbon black, and zeolite.

  If it is set as the 1st adsorption | suction part which has the component of this structure, a disturbance component can be adsorb | sucked.

It is the schematic which shows a gas detection element. It is the schematic of a bridge circuit. It is the schematic of the gas detector of the example of this invention (invention example 1). It is the schematic of the gas detector of another embodiment (invention example 2 and 3). It is the schematic of the gas detector of a comparison sensor (comparative examples 1, 3, and 4). It is the schematic of the gas detector of a comparison sensor (comparative example 2). It is the schematic of the gas detector of a comparison sensor (comparative example 5). It is the graph which showed the result of Example 1 (siloxane compound durability).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, the gas detector X of the present invention includes a gas detection element 10 having a gas sensitive portion 12 that comes into contact with a gas to be detected. The gas detection element 10 is accommodated in double casings 51 and 52, and the outer casing 51 outside the dual casings 51 and 52 includes a gas inlet 20 for introducing a gas to be detected and an obstruction. The 1st adsorption | suction part 31 which absorbs a component is provided.

  The inner case 52 in the double case includes a decomposition catalyst part 34 for decomposing the disturbing component and a second adsorption part 32 for absorbing the disturbing component in this order from the introduction direction of the gas to be detected.

  The inner housing 52 includes a restriction vent (restriction means) 40 having an opening area smaller than that of the gas inlet 20. The restriction vent (restricting means) 40 restricts the inflow of disturbing components, and is disposed between the first adsorption part 31 and the decomposition catalyst part 34.

  In the present embodiment, a case where two adsorbing units (first adsorbing unit 31 and second adsorbing unit 32) are provided as the adsorbing unit 30 will be described. May be provided. Each adsorption | suction part 31 and 32 may be formed with a single material, and may form one adsorption | suction part combining several different materials.

  In the present embodiment, a hot-wire semiconductor gas detection element is exemplified as the gas detection element 10, but is not limited thereto. Other gas detection elements include conventionally known gas detection elements such as catalytic combustion type gas detection elements, substrate type semiconductor type gas detection elements, solid electrolyte type gas detection elements, and gas detection elements using MEMS technology.

  The hot wire type semiconductor gas detection element 10 has a gas sensitive part 12 whose main component is a metal oxide which is covered with a coiled noble metal wire 11 and sintered. The noble metal wire 11 has the same material, wire diameter, coil diameter, number of coil turns, and the like as those used in a conventional hot-wire semiconductor gas detection element, and is not particularly limited. As the material of the noble metal wire 11, platinum or the like can be applied.

  The gas sensitive part 12 can use a metal oxide semiconductor. As the metal oxide semiconductor, for example, tin oxide, indium oxide, zinc oxide and the like can be used, but are not particularly limited.

  As shown in FIG. 2, the gas detector X according to the present embodiment includes a hot-wire semiconductor gas detection element 10 that detects a gas to be detected (flammable gas such as LPG, methane, hydrogen, or carbon monoxide), a fixed The load resistor R0 and the fixed opposite side resistors R1 and R2 are incorporated in the bridge circuit. The bridge circuit constantly supplies a voltage from the power source E, and holds the hot-wire semiconductor gas detection element 10 at a temperature at which the gas to be detected reacts.

The gas detection element 10 is accommodated in the housing 50. The gas detector X of the present invention has a double casing structure, and the casing 50 includes an outer casing 51 on the outside and an inner casing 52 covered with the outer casing 51.
At one end of the outer casing 51, a gas inlet 20 that is an opening for introducing a gas to be detected is formed. A first adsorbing portion 31 that absorbs disturbing components is disposed on the gas inlet 20 side inside the outer casing 51. An explosion-proof wire mesh 21 is disposed between the gas inlet 20 and the first adsorption portion 31.

  The first adsorbing portion 31 contains an adsorbent that adsorbs various interfering components such as organic silicone gas, siloxane compound, alcohol, and toluene floating in the room. As the adsorbent, for example, activated carbon, carbon black, zeolite, and the like can be applied, and an oxidation catalyst (Fe, Mn, etc.) may be added to these materials, or an acidic adsorbent or a basic adsorbent may be attached by attaching a chemical. Also good. Further, the activated carbon may be a sulfonated activated carbon or may carry a heteropoly acid salt. The adsorbent material may be a single material or a combination of a plurality of different materials. The shape of these adsorbents is not particularly limited, and for example, a fibrous shape, a spherical shape, a granular shape, or the like can be applied.

  At one end of the inner casing 52, a restricted vent 40 having an opening area smaller than that of the gas inlet 20 is formed. In addition, a decomposition catalyst portion 34 that decomposes the disturbing component and a second adsorption portion 32 that absorbs the disturbing component are disposed inside the inner housing 52.

  The decomposition catalyst unit 34 contains components that decompose the interfering components, and such components are preferably formed of, for example, a carbon-based material carrying a noble metal. Pt, Pd, Ru, or the like can be used as the noble metal used for the decomposition catalyst portion 34, and activated carbon, carbon black, or the like can be used as the carbon-based material, but is not limited thereto. . The precious metal used may be 5 to 15% by weight. The shape of the decomposition catalyst portion 34 is not particularly limited, and for example, a powder shape, a fiber shape, a spherical shape, a granular shape, or the like can be applied.

The second adsorption unit 32 is disposed on the downstream side (gas detection element 10 side) of the decomposition catalyst unit 34. The second adsorbing portion 32 contains an adsorbent that adsorbs the interfering component, and such an adsorbent is preferably formed of a solid acid catalyst. As the solid acid catalyst, for example, silica alumina is preferably used in consideration of cost. In addition, a heteropoly acid salt (such as cesium, barium, and rubidium salts of phosphotungstic acid), sulfated zirconia, and tungstic acid. Zirconia, sulfonated activated carbon, sulfonated carbon, sulfonated ion exchange resin, Y-type high silica zeolite, Al-containing mesoporous silica and the like can also be used. Since the heteropolyacid salt is a solid superacid, it has a smaller capacity than silica alumina and can provide adsorption performance equivalent to that of silica alumina, which is suitable for downsizing the housing. Note that the adsorbent of the second adsorbing portion 32 is not limited to these. In addition, a material in which Pt, Pd, or the like is mixed or supported thereon may be used as the second adsorption portion 32.
Further, the second adsorbing portion 32 may be a product obtained by impregnating a gas-permeable porous sheet or non-woven fabric with a mixed dispersion liquid such as the above-described adsorbent and silica sol for a binder and holding it dry.

  In the present embodiment, the second adsorption unit 32 is not mixed with the cracking catalyst unit 34, and the step of mixing them can be omitted, so that the production efficiency of the gas detector X is improved.

  In the present embodiment, porous sheets 41 and 42 having air permeability are disposed on the upper side of the decomposition catalyst part 34 and the lower side of the second adsorption part 32 in order to stabilize the shapes thereof. When the shape of the decomposition catalyst portion 34 is highly stable, the upper and lower porous sheets 41 and 42 may be omitted, and an explosion-proof wire mesh 43 is disposed on the lower surface of the lower porous sheet 42. . Further, on the lower surface of the explosion-proof wire mesh 43, there is disposed a stop member 44 that can be positioned in a state where the decomposition catalyst portion 34, the second adsorption portion 32, the porous sheets 41 and 42, and the explosion-proof wire mesh 43 are laminated. is there.

  The restricted vent 40 is disposed between the first adsorption part 31 and the decomposition catalyst part 34. The opening area of the restricted vent 40 is set smaller than the opening area of the gas inlet 20. In the present embodiment, the opening area of the restricted vent 40 is 11% with respect to the opening area of the gas inlet 20, but is not limited to such an aspect.

  In the gas detector X of the present invention, the housing 50 that houses the gas detector X has a double housing structure. Therefore, when assembling the gas detector X, a space for accommodating the first adsorption unit 31, the decomposition catalyst unit 34, and the second adsorption unit 32 can be easily formed simply by assembling the outer casing 51 and the inner casing 52. can do.

  In the present embodiment, the introduced gas introduced into the outer casing 51 from the gas inlet 20 first passes through the first adsorption unit 31. At this time, if the introduced gas contains an interfering component, it is adsorbed by the first adsorption unit 31.

  When all of the disturbing components are not adsorbed by the first adsorbing portion 31, the remaining disturbing components reach the decomposition catalyst portion 34 in the inner casing 52 via the restricted vent 40. At this time, since the opening area of the restricted vent 40 is set to be smaller than the opening area of the gas inlet 20, the amount of disturbing components introduced into the decomposition catalyst unit 34 can be greatly reduced. The disturbing component introduced into the decomposition catalyst unit 34 is decomposed by the decomposition catalyst unit 34. When all of the interfering components are not decomposed by the decomposition catalyst unit 34, the remaining interfering components reach the second adsorption unit 32 and are adsorbed by the second adsorption unit 32.

  As described above, since the interference component is decomposed or adsorbed by passing through the decomposition catalyst portion 34 and the second adsorption portion 32 in the inner housing 52, the interference component reaching the gas detection element 10 is extremely reduced. Therefore, the gas detector X of the present invention includes the first adsorption unit 31, the decomposition catalyst unit 34, and the second adsorption unit 32, so that even when used in a kitchen or the like where various disturbing components such as siloxane compounds exist. The influence of various interference components can be made even more difficult.

Further, since the opening area of the restricted vent 40 is set smaller than the opening area of the gas inlet 20, the detached gas released from the adsorbent due to the temperature increase of the first adsorbing portion 31 is on the side of the gas detection element 10. It becomes easy to move to the outside of the housing 50 through the gas inlet 20 having a larger opening area. Therefore, it is possible to prevent the separation gas from being detected even though the gas to be detected does not exist.
In the present embodiment, the case where one restricted vent 40 is provided has been described, but the number of the restricted vents 40 is preferably one. If a plurality of restricted vents 40 are formed at one end of the inner housing 52, the effect of reducing the inflow of disturbing components by one restricted vent 40 will be reduced.

[Another embodiment]
In the embodiment described above, the inner housing 52 includes the third adsorption part 33 that absorbs the disturbing component so as to be between the restricted vent 40 and the decomposition catalyst part 34 (upstream of the decomposition catalyst part 34). (Figure 4). The third adsorbing part 33 may be formed of a solid acid catalyst in the same manner as the second adsorbing part 32.

  In this configuration, the third adsorption portion 33 is disposed downstream (on the gas detection element 10 side) of the restriction vent (restriction means) 40. In this state, the third adsorbing portion 33 can adsorb the obstructing component via the restricted vent 40, so that the obstructing component introduced into the decomposition catalyst portion 34 disposed on the downstream side of the third adsorbing portion 33. The amount can be greatly reduced.

[Example 1]
Assuming the environment used in the kitchen, the performance (siloxane compound durability) of the hot-wire semiconductor gas detector X of the present invention (Invention Examples 1 to 3) was examined. The gas to be introduced was a mixed gas having 250 ppm of toluene + 5 ppm of OMCTS (siloxane gas). A similar test was performed for the comparative sensor (Comparative Examples 1 to 5).
The sensor drive was pulsed drive (heating the sensor element to around 500 ° C. for 0.1 seconds every 30-second period to detect methane gas), and the methane alarm set concentration was 3000 ppm.

  In Inventive Examples 1 to 3 and Comparative Examples 1 to 5, fibrous activated carbon (70 mg) was used for the first adsorption part 31.

  In Invention Examples 1 to 3, the decomposition catalyst part 34 used platinum-supported activated carbon powder (25 mg, Pt: 10% by weight). Further, in Example 1 of the present invention (the embodiment of FIG. 3), the third adsorption part 33 was not provided, and silica alumina powder (15 mg) was used in the second adsorption part 32. In Example 2 of the present invention (the embodiment of FIG. 4), silica alumina powder (7.5 mg) was used in the second adsorption part 32 and the third adsorption part 33. In Example 3 of the present invention (the same mode as in FIG. 4), platinum-containing silica alumina powder (7.5 mg, Pt: 3 wt%) was used in the second adsorbing part 32 and the third adsorbing part 33. Details of each example of the present invention are shown in Table 1.

In Comparative Examples 1 to 5, the following configuration was used as the comparison unit 35 instead of the second adsorption unit 32, the third adsorption unit 33, and the decomposition catalyst unit 34. That is, in Comparative Example 1 (the embodiment shown in FIG. 5), a mixed powder of 25 mg of activated carbon powder and 15 mg of silica alumina powder was used as the comparison unit 35.
In Comparative Example 2 (aspect of FIG. 6), as the comparison part 35, a silica alumina powder layer 36 (7.5 mg), an activated carbon powder layer 37 (25 mg), and a silica alumina powder layer 36 (7.5 mg) were laminated in this order. I used something.
In Comparative Example 3 (the same mode as in FIG. 5), platinum-supported activated carbon powder (40 mg, Pt: 10% by weight) was used as the comparison unit 35.
In Comparative Example 4 (the same mode as in FIG. 5), a mixed powder of platinum-supported activated carbon powder 25 mg (Pt: 10 wt%) and silica alumina powder 15 mg was used as the comparison unit 35.
In Comparative Example 5 (the embodiment of FIG. 7), the silica alumina powder layer 36 (15 mg) and the platinum-supported activated carbon powder layer 38 (25 mg, Pt: 10% by weight, corresponding to the decomposition catalyst part 34) were used as the comparison part 35. .

The results are shown in FIG.
Comparative Examples 1 and 2 are a combination of activated carbon and silica alumina powder (adsorbent alone and no decomposition catalyst part 34), both of which are about 330 days lower limit of alarm concentration (1/3 (1000 ppm) of methane alarm set concentration) ). Comparative Example 3 was only platinum-supported activated carbon (corresponding to the decomposition catalyst unit 34), and the alarm concentration dropped sharply after 300 days and fell below the lower limit of the alarm concentration in about 370 days. Comparative Example 4 is a mixed powder of platinum-supported activated carbon and silica alumina, which fell below the lower limit of the alarm concentration in about 400 days. In Comparative Example 5, the silica alumina layer was disposed upstream of the silica alumina powder layer 36 and the platinum-supported activated carbon layer (corresponding to the decomposition catalyst portion 34), but the alarm concentration fell below the lower limit value in about 420 days.

On the other hand, when the 2nd adsorption part 32 was arranged downstream of decomposition catalyst part 34 like example 1 of the present invention, it was possible to extend up to about 450 days to fall below the lower limit of alarm concentration.
Moreover, when the 3rd adsorption | suction part 33 is arrange | positioned upstream of the decomposition catalyst part 34 like the example 2 of this invention, and the 2nd adsorption | suction part 32 is arrange | positioned downstream, it will be 2/3 (2/3 () 2000 ppm).
Furthermore, if platinum was added to the second adsorbing part 32 and the third adsorbing part 33 as in Invention Example 3, 5/6 (2500 ppm) of the methane alarm set concentration was maintained even for about 480 days.

Therefore, when there is no decomposition catalyst part (platinum-supported activated carbon) as in Comparative Examples 1 and 2, when only the decomposition catalyst part is used as in Comparative Example 3, the decomposition catalyst part and silica alumina as in Comparative Example 4 are used. In the case of the mixed powder, it was recognized that the durability of the siloxane compound was remarkably improved in Examples 1 to 3 of the present invention compared to the case where the silica alumina layer was disposed upstream of the decomposition catalyst portion as in Comparative Example 5.
That is, as in the present application, the cracking catalyst part 34 and the second adsorption part 32 are formed in different layers, and the second adsorption part 32 is disposed at least downstream of the cracking catalyst part 34, whereby the gas detector X is made of siloxane. Even when used in kitchens where various interfering components such as compounds exist, it has been recognized that the effects of various interfering components can be made even less susceptible.

[Example 2]
The gas response to the detected gas (methane gas) was investigated.
In the sensors of Invention Examples 1 to 3 and Comparative Examples 1 to 5 described above, the time required for response was measured with respect to 12500 ppm of methane gas. Sensor driving was performed under the same conditions as in Example 1. The results are shown in Table 2.

As a result, Examples 1 to 3 of the present invention required a response time of 21 to 23 seconds, and were found to have a response equal to or higher than that of Comparative Examples 1 to 5. Therefore, it was recognized that the gas detector X of the present invention can be made more difficult to be affected by various disturbing components while having excellent gas responsiveness.
In addition, the responsiveness of Comparative Example 3 is extremely low due to the specific surface area of the platinum-supported activated carbon. In Examples 1-3 of the present invention, in addition to platinum-supported activated carbon, by using silica alumina belonging to a solid acid catalyst having a specific surface area smaller than that of platinum-supported activated carbon, in addition to excellent adsorptivity and durability, high responsiveness is achieved. Realized.

  INDUSTRIAL APPLICABILITY The present invention can be used for a gas detector provided with a gas detection element having a gas sensitive part that comes into contact with a gas to be detected.

X Gas detector 10 Gas detection element 12 Gas sensitive part 20 Gas inlet 31 First adsorber 32 Second adsorber 33 Third adsorber 34 Decomposition catalyst part 40 Restricted vent (restricting means)
51 Outer casing 52 Inner casing

Claims (6)

A gas detector including a gas detection element having a gas sensitive portion that comes into contact with a gas to be detected,
A double housing for accommodating the gas sensing element;
The outer outer casing in the double casing includes a gas inlet for introducing the gas to be detected and a first adsorption part for absorbing the disturbing component,
The gas detector provided with an inner case inside the double case including a decomposition catalyst part for decomposing the disturbing component and a second adsorption part for absorbing the disturbing component in this order from the introduction direction of the gas to be detected. .   The gas detector according to claim 1, further comprising a restricting unit that restricts an inflow of interfering components between the first adsorption unit and the cracking catalyst unit.   The gas detector according to claim 2, wherein the inner casing includes a third adsorption portion that absorbs the interfering component on the upstream side of the decomposition catalyst portion.   The gas detector according to claim 3, wherein the second adsorption part and the third adsorption part are each formed of a solid acid catalyst.   The gas detector according to any one of claims 1 to 4, wherein the decomposition catalyst part is formed of a carbon-based material supporting a noble metal.   The gas detector according to any one of claims 1 to 5, wherein the first adsorption part is formed of any one of activated carbon, carbon black, and zeolite.

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