WO2022181503A1 - Gas filter, gas sensor and gas sensing device - Google Patents

Gas filter, gas sensor and gas sensing device Download PDF

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Publication number
WO2022181503A1
WO2022181503A1 PCT/JP2022/006781 JP2022006781W WO2022181503A1 WO 2022181503 A1 WO2022181503 A1 WO 2022181503A1 JP 2022006781 W JP2022006781 W JP 2022006781W WO 2022181503 A1 WO2022181503 A1 WO 2022181503A1
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Prior art keywords
gas
molecular sieve
gas sensor
gas filter
filter
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PCT/JP2022/006781
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French (fr)
Japanese (ja)
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紘輝 重野
剛士 植田
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パナソニックＩｐマネジメント株式会社
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Publication of WO2022181503A1 publication Critical patent/WO2022181503A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/14—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature
    • G01N27/16—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas

Definitions

  • the present disclosure relates to a gas filter, a gas sensor, and a gas detection device, and more particularly to a gas filter that can be provided in a gas sensor, a gas sensor including this gas filter, and a gas detection device including this gas sensor.
  • Patent Document 1 discloses a heating means, a porous body formed by controlling an average pore diameter to 10 ⁇ or less with a coating containing one or more kinds of silica or zirconia, and a gas detector that contacts gas through the porous body.
  • a gas sensor is disclosed.
  • This porous body is constructed by forming a hydrophobic pore control film containing silica or the like on the surface and inner surfaces of the pores of a ceramic porous substrate. In this gas sensor, the porous body blocks the inflow of kerosene vapor, silicone compounds, and the like, thereby enhancing durability.
  • An object of the present disclosure is to provide a gas filter that can inhibit the permeation of silicone-based compounds and the like over a long period of time while ensuring gas permeation, a gas sensor that includes this gas filter, and a gas detection device that includes this gas sensor.
  • a gas filter according to one aspect of the present disclosure includes a molecular sieve layer having pores with a pore size of less than 2 nm, and a porous substrate overlapping the molecular sieve layer.
  • a gas sensor includes a gas sensing unit, a gas sensor chamber in which the gas sensing unit is arranged, a gas flow channel through which gas supplied to the gas sensor chamber flows, and provided in the gas flow channel, and the gas filter arranged so that the space in the gas sensor chamber intervenes between the gas sensitive part and the gas sensor.
  • a gas detection device includes the gas sensor and a detection section that detects an output of the gas sensitive section of the gas sensor.
  • FIG. 1 is a schematic cross-sectional view showing a gas filter and gas sensor in an example embodiment of the present disclosure.
  • FIG. 2 is an enlarged cross-sectional view of a main part showing another example of the above embodiment.
  • FIG. 3 is an enlarged cross-sectional view of a main part showing still another example of the above embodiment.
  • FIG. 4 is a scanning electron micrograph of a cross-section of a gas filter, in one embodiment of the present disclosure;
  • FIG. 5 is a graph showing the results of the gas permeability evaluation test of the above example.
  • FIG. 6 is a graph showing the results of a permeability evaluation test for toxic components in the above example.
  • Patent Document 1 Japanese Patent Laid-Open No. 10-115597
  • gas is allowed to permeate through a porous body, thereby making it difficult for components such as silicone-based compounds that poison the gas sensitive portion to permeate.
  • Patent Document 1 may not be able to efficiently detect the components in the gas. This is because, as disclosed in Patent Document 1, when a ceramic porous substrate is coated with a pore control film to produce a porous body, the porosity of the porous body becomes small, and as a result, it is difficult for gas to permeate the porous body. This is thought to be for the sake of However, if the pore size is increased to facilitate gas permeation, toxic components such as silicone compounds will permeate.
  • the inventors have also considered using an adsorbent that adsorbs toxic components, such as activated carbon. It is difficult to maintain the performance over a long period of time because the performance of adsorbing the components deteriorates.
  • the inventor has advanced research and development to provide a gas filter that can inhibit permeation of silicone-based compounds and the like for a long period of time while ensuring gas permeation, and has completed the present disclosure.
  • the gas filter 1 includes a molecular sieve layer 2 having pores with a pore size of less than 2 nm, and a porous substrate 3 overlapping the molecular sieve layer 2 .
  • the porous substrate 3 may directly overlap the molecular sieve layer 2, or may overlap the molecular sieve layer 2 via a layer other than the molecular sieve layer 2.
  • having the molecular sieve layer 2 makes it difficult for toxic components such as silicone-based compounds to permeate the gas filter 1 due to the molecular sieve action.
  • the pore diameter of the pores in the molecular sieve layer 2 is less than 2 nm, the pore diameter of the pores is smaller than that of many molecules of silicone compounds, which are typical poisonous components. Permeation can be effectively suppressed.
  • the molecular sieve layer 2 inhibits permeation of toxic components by its molecular sieving action, the effect of inhibiting permeation of toxic components is less likely to decrease over time as compared with the adsorbent.
  • the porous substrate 3 overlaps the molecular sieve layer 2 , the porous substrate 3 can support the molecular sieve layer 2 . Therefore, it is easy to reduce the thickness of the molecular sieve layer 2, so that the length of pores in the molecular sieve layer 2 can be reduced. Therefore, the molecular sieve layer 2 inhibits the permeation of the poisoning component and hardly inhibits the permeation of the gas.
  • the gas filter 1 according to the present embodiment can inhibit the permeation of silicone-based compounds and the like in the gas for a long period of time while ensuring the permeation of the gas.
  • the material of the porous substrate 3 is not particularly limited, but the material of the porous substrate 3 is, for example, porous ceramic, porous glass, or porous resin.
  • the pore size of the pores of the porous substrate 3 is preferably larger than the pore size of the pores of the molecular sieve layer 2 .
  • the porous substrate 3 is particularly difficult to inhibit gas permeation.
  • the porous substrate 3 has pores with a pore diameter of 2 nm or more and 200 nm or less.
  • the thickness of the porous substrate 3 is appropriately adjusted so that the porous substrate 3 has sufficient strength to support the molecular sieve layer 2 and the porous substrate 3 does not easily inhibit gas permeation. preferably adjusted.
  • the thickness of the porous substrate 3 is, for example, 0.1 mm or more and 1 mm or less.
  • the pore diameter of the pores of the porous substrate 3 is the average pore diameter measured by the mercury porosimetry.
  • the surface of the porous substrate 3 facing the molecular sieve layer 2 may be uneven (see FIG. 2).
  • the gas filter 1 is more gas permeable. It is presumed that this is because the molecular sieve layer 2 becomes uneven along the shape of the porous substrate 3, and thus the surface area of the molecular sieve layer 2 increases. Since the surface facing the molecular sieve layer 2 is uneven, it is preferable that the developed area ratio (Sdr) of the interface on this surface is 0.1 or more. In this case, the gas filter 1 can be particularly permeable to gas.
  • the developed area ratio (Sdr) of this interface can be calculated from the result of measuring the surface roughness of this surface using a laser microscope.
  • the molecular sieve layer 2 has pores with a pore diameter of less than 2 nm, as described above. For this reason, the molecular sieve layer 2 has a molecular sieve effect, which makes it difficult for poisonous components such as silicone-based compounds to permeate. Since the diameter of the silicone-based compound that can float in the gas is about 1 to 2 nm, it will permeate porous glass having pores with a pore diameter of about 4 nm, for example. If the diameter is less than 2 nm, the permeation of the silicone compound having the above diameter can be sufficiently inhibited.
  • the pore size is more preferably 1.5 nm or less, and even more preferably 1.2 nm or less. Also, the pore size of the pores is preferably 0.5 nm or more, more preferably 0.6 mm or more. In this case, the molecular sieve layer 2 is less likely to inhibit gas permeation.
  • the pore size of the pores of the molecular sieve layer 2 is the average pore size obtained by the t-plot method of nitrogen adsorption measurement.
  • the thickness of the molecular sieve layer 2 is, for example, 0.1 ⁇ m or more and 5 ⁇ m or less. If the thickness is 0.1 ⁇ m or more, the molecular sieve layer 2 can particularly inhibit permeation of toxic components such as silicone compounds. Moreover, if the thickness is 5 ⁇ m or less, the molecular sieve layer 2 is particularly unlikely to inhibit gas permeation.
  • This thickness is more preferably 0.2 ⁇ m or more, more preferably 0.3 ⁇ m or more, and particularly preferably 0.5 ⁇ m or more.
  • the thickness is more preferably 2 ⁇ m or less, more preferably 1.5 ⁇ m or less, and particularly preferably 1 ⁇ m or less.
  • the material of the molecular sieve layer 2 is not limited, but the molecular sieve layer 2 preferably contains silica or polysiloxane. In this case, the molecular sieve layer 2 can be produced from readily available materials by a relatively simple technique.
  • the molecular sieve layer 2 is, for example, a single layer, that is, a layer composed of substantially homogeneous material over its entirety.
  • the molecular sieve layer 2 is a single layer, molding conditions according to the pore diameter of the substrate, etc., are different compared to the case where the molecular sieve is produced by coating the inner surfaces of the pores in the porous substrate. Adjust becomes unnecessary.
  • the molecular sieve layer 2 can be produced by molding a substantially homogeneous material, it is advantageous in terms of the manufacturing process compared to the case where the inner surfaces of the pores are coated. Therefore, the molecular sieve layer 2 can be easily produced.
  • the molecular sieve layer 2 may not be a single layer.
  • the molecular sieve layer 2 is produced by an appropriate method.
  • the molecular sieve layer 2 is produced by a sol-gel method.
  • a sol is prepared by adding and mixing a catalyst and an alkoxysilane precursor to a solvent, and the sol is applied to the porous substrate 3 and heated to gel. Thereby, the molecular sieve layer 2 can be produced.
  • the porous substrate 3 In order to suppress defects in the molecular sieve layer 2, it is preferable to first heat the porous substrate 3 and then apply a sol to prepare a gelled coating. Subsequently, the porous substrate 3 is heated again, and the sol is applied over the film to gel it and increase the thickness of the film. The heating of the porous substrate 3 and the application of the sol are repeated several times, and then the coating is further heated to produce the molecular sieve layer 2 .
  • the solvent contains, for example, water and an organic solvent.
  • the organic solvent is preferably an amphiphilic solvent compatible with both water and the alkoxysilane precursor, such as a lower alcohol such as ethanol.
  • Any suitable acid catalyst or base catalyst can be used as the catalyst. Acid catalysts include, but are not limited to, hydrochloric acid, sulfuric acid, or nitric acid.
  • Alkoxysilane precursors include, for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, and 1,4- It contains at least one selected from the group consisting of bis(triethoxysilyl)benzene and the like.
  • the type of alkoxysilane precursor it is possible to control the pore size of the pores of the molecular sieve layer 2 and the physical properties of the molecular sieve layer 2 .
  • the method for producing the molecular sieve layer 2 is not limited to the sol-gel method.
  • the molecular sieve layer 2 may be produced by chemical vapor deposition.
  • the gas filter 1 may further include an adsorbent layer 4 (see FIG. 3).
  • the adsorbent layer 4 is a layer made of adsorbent.
  • the adsorbent layer 4 adsorbs toxic components that permeate the molecular sieve layer 2 due to reasons such as relatively small molecular size, thereby further inhibiting the permeation of the toxic components through the gas filter 1. be able to.
  • the adsorbent layer 4 is made of an appropriate adsorbent capable of adsorbing poisonous components.
  • the adsorbent layer 4 is made of at least one adsorbent selected from the group consisting of activated carbon, silica gel, zeolite and porous resin.
  • the adsorbent layer 4 is produced, for example, by molding and sintering adsorbent particles.
  • the thickness of the adsorbent layer 4 is, for example, 0.5 mm or more and 5 mm or less.
  • the molecular sieve layer 2 and the adsorbent layer 4 are preferably arranged in this order along the direction in which the gas permeates the gas filter 1.
  • the molecular sieve layer 2 first inhibits the permeation of the relatively large molecules, followed by the relatively small molecules. Molecules are adsorbed on the adsorbent layer 4 . For this reason, the permeation of toxic components is particularly effectively inhibited.
  • the amount of poisoning components adsorbed by the adsorbent layer 4 can be reduced. Therefore, the performance of the adsorbent layer 4 can be maintained over a long period of time, and thus the performance of the gas filter 1 can be maintained over a long period of time.
  • the adsorbent layer 4 overlaps, for example, the surface of the porous substrate 3 opposite to the surface where the molecular sieve layer 2 overlaps. That is, for example, as shown in FIG. 3, the molecular sieve layer 2, the porous substrate 3, and the adsorbent layer 4 are stacked in this order along the direction of gas permeation through the gas filter 1. ing. Also, the adsorbent layer 4 may be interposed between the porous substrate 3 and the molecular sieve layer 2 . That is, the molecular sieve layer 2, the adsorbent layer 4, and the porous substrate 3 may be stacked in this order along the direction in which gas permeates through the gas filter 1. FIG.
  • the porous substrate 3 may have a function of adsorbing poisonous components such as silicone compounds.
  • the porous substrate 3 may contain an adsorbent. If the porous substrate 3 has a function of adsorbing the poisonous component, the porous substrate 3 functions in the same manner as the adsorbent layer 4 described above, effectively inhibiting the permeation of the poisonous component. In this case, the gas filter 1 may not have the adsorbent layer 4 .
  • the porous substrate 3 may have a function of adsorbing the poisonous component, and the gas filter 1 may be provided with the adsorbent layer 4 . In that case, the permeation of toxic components is inhibited more effectively.
  • the gas filter 1 according to this embodiment is suitable for the gas sensor 8.
  • the gas filter 1 according to the present embodiment can be applied to various uses other than the gas sensor 8 in which its characteristics can be used.
  • a gas sensor 8 provided with the gas filter 1 according to this embodiment and a gas detection device provided with this gas sensor 8 will be described.
  • the gas sensor 8 includes a gas sensitive portion 5 , a gas sensor chamber 6 , a gas flow path 7 and a gas filter 1 .
  • a gas sensitive part 5 is arranged in the gas sensor chamber 6 .
  • the gas flow path 7 is a flow path leading to the gas sensor chamber 6 through which the gas supplied to the gas sensor chamber 6 permeates.
  • the gas filter 1 according to this embodiment is provided in the gas flow path 7 and arranged so that the space in the gas sensor chamber 6 intervenes between it and the gas sensing portion 5 . In other words, there is a gap between the gas filter 1 and the gas sensitive part 5 .
  • the gas passes through the gas flow path 7, passes through the gas filter 1, is supplied to the gas sensor chamber 6, and contacts the gas sensing portion 5. Therefore, even if the gas contains a poisonous component such as a silicone-based compound, the gas filter 1 prevents the permeation of the poisonous component, making it difficult for the poisonous component to reach the gas sensing portion 5 . Therefore, the gas sensing portion 5 is less likely to be poisoned by the toxic component, and the performance of the gas sensing portion 5 can be maintained for a long period of time.
  • a poisonous component such as a silicone-based compound
  • the space in the gas sensor chamber 6 is interposed between the gas sensing portion 5 and the gas sensing portion 5, compared with the case where the gas sensing portion 5 is directly covered with the gas filter 1, the gas reaching the gas sensing portion 5 is more difficult. hard to hinder. Therefore, the sensitivity of the gas sensing portion 5 is less likely to be impaired by the gas filter 1 .
  • the gas sensitive part 5 is, for example, a suitable sensor element that produces an output according to the components in the gas when it comes into contact with the gas.
  • the output is, for example, a change in physical properties such as electrical resistance or an electrical signal.
  • the gas sensitive part 5 is, for example, a semiconductor sensor element, a catalytic combustion sensor element, an electrochemical sensor element, or the like.
  • the gas sensitive part 5 is arranged as described above. A space to which gas is supplied is formed inside the gas sensor chamber 6, and the gas sensitive part 5 is arranged in this space.
  • the form of the gas channel 7 is not particularly limited as long as it communicates with the inside of the gas sensor chamber 6 and can supply gas from the gas channel 7 to the inside of the gas sensor chamber 6 .
  • the gas flow path 7 may be a pipeline connected to the gas sensor chamber 6 or may be an opening formed in the gas sensor chamber 6 .
  • the interior of the gas sensor chamber 6 is hermetically sealed except for communicating with the gas flow path 7 , and is constructed so that all the gas flowing through the gas flow path 7 passes through the gas filter 1 before flowing into the gas sensor chamber 6 .
  • the gas filter 1 is provided so as to close the gas flow path 7, that is, to divide the gas flow path 7 into an upstream side and a downstream side in the gas flow direction.
  • a pressure difference occurs between the inside and the outside of the gas sensor chamber 6, causing the gas filter 1 to The inflow of gas into the gas sensor chamber 6 through is promoted. Therefore, the efficiency of gas detection can be increased.
  • the case where the volume of gas in the gas sensor chamber 6 decreases during the process of gas detection by the gas sensing section 5 is, for example, the case where the gas sensing section 5 is a catalytic combustion type sensor element for detecting carbon monoxide.
  • the gas sensing section 5 is a catalytic combustion type sensor element for detecting carbon monoxide.
  • the volume of the gas decreases.
  • the volume of gas is similarly reduced by a chemical reaction, and the inflow of gas can be promoted.
  • the ratio of the volume of the space of the gas sensor chamber 6 to the planar view area of the gas filter 1 is preferably as small as possible, particularly preferably 2 mm 3 /mm 2 or less.
  • planar view means seeing the gas filter 1 in the thickness direction.
  • the gas sensor 8 can be more responsive when detecting the component to be detected in the gas. It is speculated that this is because the smaller the ratio, the higher the concentration of the component to be detected in the gas sensor chamber 6 when the gas is supplied into the gas sensor chamber 6 through the gas filter 1. be done.
  • the gas detection device includes the gas sensor 8 according to this embodiment and a detection section that detects the output of the gas sensing section 5 in the gas sensor 8 .
  • the detection section is a detection circuit that detects the component to be measured in the gas based on the output of the gas sensing section 5, for example, or further measures the concentration of this component in the gas.
  • the gas detection device is configured, for example, as a gas alarm.
  • a porous glass substrate having an average pore diameter of 50 nm and a thickness of 1 mm was prepared as the porous substrate 3 .
  • the sol was applied on the porous substrate 3 to prepare a gelled film.
  • the coating was coated with a sol and gelled, thereby increasing the thickness of the gelled coating.
  • the gelled coating was heated at 180° C. for 2 hours.
  • the molecular sieve layer 2 was produced, and the gas filter 1 including the molecular sieve layer 2 and the porous substrate 3 was obtained.
  • a scanning electron microscope photograph of the cross section of this gas filter 1 is shown in FIG.
  • the thickness of the molecular sieve layer 2 in this gas filter 1 was 0.9 ⁇ m.
  • the average pore diameter of this molecular sieve layer 2 obtained by the t-plot method of nitrogen adsorption measurement was 0.85 nm.
  • a gas sensor 8 for testing was produced as follows. TGS8100 manufactured by Figaro Engineering Co., Ltd. was arranged as the gas sensitive part 5 on the printed circuit board, and the gas filter 1 was arranged above it. By interposing an O-ring between the gas filter 1 and the printed wiring board, the space around the gas sensitive part 5 was sealed from the outside. As a result, the gas sensing part 5 was arranged in a space having a planar view area of 200 mm 2 and a height of 1 mm, and this space was sealed except for the entire top surface of which was blocked by the gas filter 1 .
  • Fig. 5 shows the measurement results of the output of the gas sensitive part 5.
  • the vertical axis of FIG. 5 indicates the electrical resistance value of the gas sensing portion 5, and the horizontal axis indicates the elapsed time.
  • the solid line “A” shows the results when the gas is injected into the gas sensor 8 through the gas filter 1
  • the dashed line “B” shows the results when the gas is directly sprayed onto the gas sensitive part 5. each shown.
  • “Injection start” indicates the time point at which gas injection is started
  • “Injection end” indicates the time point at which gas injection is finished.
  • the amount of change in electrical resistance when gas is injected into the inside of the gas sensor 8 through the gas filter 1 is about the same as when the gas is directly blown onto the gas sensitive part 5. Therefore, no decrease in sensitivity due to the use of the gas filter 1 is observed. Further, when the gas was directly blown onto the gas sensing part 5, the electrical resistance value stopped decreasing about 15 seconds after the start of gas injection. In this case, the electric resistance value stopped decreasing about 22 seconds after the start of gas injection. Therefore, the delay in response due to the use of the gas filter 1 is only about 7 seconds, and it can be evaluated that the effect of the gas filter 1 on the responsiveness is sufficiently small.
  • the gas filter 1 is less likely to inhibit gas permeation.
  • Toxic Component Permeability Evaluation Test Two containers having a volume of 200 cm 3 and an opening area of 200 mm 2 were prepared, and the openings of these containers were connected to face each other via a gas filter 1 . A gap between the gas filter 1 and the edge of each opening was closed with a rubber packing. A siloxane gas was generated by bubbling decamethylcyclopentasiloxane in a container, and this siloxane gas was pumped into one of the containers. The other container was connected to a multi-gas monitor, and the siloxane gas concentration in this container was measured.
  • the results are shown in Figure 6.
  • the vertical axis indicates the measurement result of the siloxane concentration
  • the horizontal axis indicates the elapsed time from the start of injection of the siloxane gas.
  • the solid line “A” shows the results when the gas filter 1 is used
  • the dashed line “B” shows the results when the gas filter 1 is not used
  • the dashed line “C” shows the results when the gas filter 1 is used instead.
  • the gas filter 1 is difficult to permeate the siloxane gas.
  • the gas filter (1) according to the first aspect of the present disclosure includes a molecular sieve layer (2) having pores with a pore size of less than 2 nm, and a molecular sieve layer (2 ) overlying the porous substrate (3).
  • the gas filter (1) can inhibit permeation of silicone-based compounds and the like for a long period of time while ensuring gas permeation.
  • the molecular sieve layer (2) is a single layer.
  • the molecular sieve layer (2) can be easily produced.
  • the pore size of the pores of the molecular sieve layer (2) is 0.5 nm or more and 1.5 nm or less.
  • the gas filter (1) can more effectively inhibit permeation of silicone compounds.
  • the molecular sieve layer (2) contains silica or polysiloxane.
  • the gas filter (1) can more effectively inhibit permeation of silicone compounds.
  • the surface of the porous substrate (3) facing the molecular sieve layer (2) is It is uneven.
  • the gas filter (1) is more permeable to gas and more effectively inhibits the permeation of silicone-based compounds and the like.
  • the gas filter (1) according to the sixth aspect of the present disclosure in any one of the first to fifth aspects, further comprises an adsorbent layer (4).
  • the gas filter (1) can more effectively inhibit permeation of silicone compounds and the like.
  • the molecular sieve layer (2) and the adsorbent layer (4) are arranged in this order so that the gas filter (1) is Lined up along the direction of transmission.
  • the gas filter (1) can inhibit permeation of silicone-based compounds and the like for a longer period of time.
  • the adsorbent layer (4) is at least selected from the group consisting of activated carbon, silica gel, zeolite and porous resin. contains one
  • the gas filter (1) can more effectively inhibit permeation of silicone compounds and the like.
  • a gas filter (1) according to a ninth aspect of the present disclosure is for a gas sensor (8) in any one of the first to eighth aspects.
  • the gas filter (1) makes it difficult for the performance of the gas sensor (8) to deteriorate due to poisoning by silicone-based compounds, etc., and the gas filter (1) provides sensitivity and responsiveness of the gas sensor (8). difficult to reduce.
  • a gas sensor (8) comprises a gas sensing portion (5), a gas sensor chamber (6) in which the gas sensing portion (5) is arranged, and a gas supplied to the gas sensor chamber (6). and a gas sensor chamber (6) provided in the gas flow path (7) and arranged so that the space in the gas sensor chamber (6) is interposed between the gas sensing part (5) and the gas sensor chamber (6).
  • a gas filter (1) according to any one of the first to ninth aspects.
  • the gas filter (1) makes it difficult for the performance of the gas sensor (8) to deteriorate due to poisoning by a silicone-based compound or the like, and the gas filter (1) provides the sensitivity and responsiveness of the gas sensor (8). difficult to reduce.
  • the gas sensor chamber (6) is sealed except for communicating with the gas flow path (7), and the gas flow path (7) is configured so that all the gas flowing through the gas flow path (7) passes through the gas filter (1) before flowing into the gas sensor chamber (6).
  • the gas filter (1) is less likely to reduce the responsiveness of the gas sensor (8).
  • the ratio of the volume of the space of the gas sensor chamber (6) to the planar view area of the gas filter (1) is It is 2 mm 3 /mm 2 or less.
  • the gas filter (1) is less likely to reduce the responsiveness of the gas sensor (8).
  • a gas detection device includes a gas sensor (8) according to any one of the tenth to twelfth aspects, and detecting an output of a gas sensitive part (5) in the gas sensor (8). and a detection unit.
  • the gas filter (1) makes it difficult for the performance of the gas detection device to deteriorate due to poisoning by a silicone compound or the like, and the gas filter (1) improves the sensitivity and responsiveness of the gas detection device. hard to lower.

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Abstract

The present disclosure provides a gas filter which is capable of inhibiting permeation of a silicone compound and the like for a long period of time, while ensuring the permeation of a gas. A gas filter (1) according to the present disclosure is provided with: a molecular sieve layer (2) that has pores having a pore diameter of less than 2 nm; and a porous base material (3) that is superposed on the molecular sieve layer (2).

Description

ガスフィルタ、ガスセンサ及びガス検知装置Gas filters, gas sensors and gas detectors
　本開示は、ガスフィルタ、ガスセンサ及びガス検知装置に関し、詳しくはガスセンサに設けることができるガスフィルタ、このガスフィルタを備えるガスセンサ、及びこのガスセンサを備えるガス検知装置に関する。 The present disclosure relates to a gas filter, a gas sensor, and a gas detection device, and more particularly to a gas filter that can be provided in a gas sensor, a gas sensor including this gas filter, and a gas detection device including this gas sensor.
　特許文献１には、加熱手段と、シリカもしくはジルコニアの一種以上を含む皮膜にて平均細孔径を１０Å以下に制御してなる多孔体と、前記多孔体を通してガスと接触するガス検知体とを有するガスセンサが開示されている。この多孔体は、セラミックの多孔体基材の表面及び細孔の内面に、シリカ等を含む疎水性の細孔制御皮膜を形成して、構成されている。このガスセンサでは、多孔体によって灯油蒸気やシリコーン系化合物などの流入をブロックして耐久性を高めている。 Patent Document 1 discloses a heating means, a porous body formed by controlling an average pore diameter to 10 Å or less with a coating containing one or more kinds of silica or zirconia, and a gas detector that contacts gas through the porous body. A gas sensor is disclosed. This porous body is constructed by forming a hydrophobic pore control film containing silica or the like on the surface and inner surfaces of the pores of a ceramic porous substrate. In this gas sensor, the porous body blocks the inflow of kerosene vapor, silicone compounds, and the like, thereby enhancing durability.
特開平１０－１１５５９７号公報JP-A-10-115597
　本開示の課題は、ガスの透過を確保しながらシリコーン系化合物などの透過を長期にわたって阻害しうるガスフィルタ、このガスフィルタを備えるガスセンサ、及びこのガスセンサを備えるガス検知装置を提供することである。 An object of the present disclosure is to provide a gas filter that can inhibit the permeation of silicone-based compounds and the like over a long period of time while ensuring gas permeation, a gas sensor that includes this gas filter, and a gas detection device that includes this gas sensor.
　本開示の一態様に係るガスフィルタは、孔径２ｎｍ未満の細孔を有する分子ふるい層と、前記分子ふるい層に重なる多孔質基材とを、備える。 A gas filter according to one aspect of the present disclosure includes a molecular sieve layer having pores with a pore size of less than 2 nm, and a porous substrate overlapping the molecular sieve layer.
　本開示の一態様に係るガスセンサは、ガス感応部と、前記ガス感応部が配置されるガスセンサ室と、前記ガスセンサ室へ供給されるガスが流れるガス流路と、前記ガス流路に設けられ、かつ前記ガス感応部との間に前記ガスセンサ室内の空間が介在するように配置されている、前記ガスフィルタとを備える。 A gas sensor according to an aspect of the present disclosure includes a gas sensing unit, a gas sensor chamber in which the gas sensing unit is arranged, a gas flow channel through which gas supplied to the gas sensor chamber flows, and provided in the gas flow channel, and the gas filter arranged so that the space in the gas sensor chamber intervenes between the gas sensitive part and the gas sensor.
　本開示の一態様に係るガス検知装置は、前記ガスセンサと、前記ガスセンサにおける前記ガス感応部の出力を検出する検出部とを備える。 A gas detection device according to an aspect of the present disclosure includes the gas sensor and a detection section that detects an output of the gas sensitive section of the gas sensor.
図１は、本開示の実施形態の一例におけるガスフィルタ及びガスセンサを示す概略の断面図である。FIG. 1 is a schematic cross-sectional view showing a gas filter and gas sensor in an example embodiment of the present disclosure. 図２は、同上の実施形態の他の例を示す要部を拡大した断面図である。FIG. 2 is an enlarged cross-sectional view of a main part showing another example of the above embodiment. 図３は、同上の実施形態の更に他の例を示す要部を拡大した断面図である。FIG. 3 is an enlarged cross-sectional view of a main part showing still another example of the above embodiment. 図４は、本開示の一実施例における、ガスフィルタの断面の走査電子顕微鏡写真である。FIG. 4 is a scanning electron micrograph of a cross-section of a gas filter, in one embodiment of the present disclosure; 図５は、同上の実施例の、ガス透過性評価試験の結果を示すグラフである。FIG. 5 is a graph showing the results of the gas permeability evaluation test of the above example. 図６は、同上の実施例の、被毒性成分の透過性評価試験の結果を示すグラフである。FIG. 6 is a graph showing the results of a permeability evaluation test for toxic components in the above example.
　ガスセンサを用いてガスを検知する場合、ガスセンサにおけるガス感応部がシリコーン化合物などに曝露されると、ガス感応部が被毒されてガスセンサの性能が低下しやすい。 When a gas sensor is used to detect gas, if the gas sensitive part of the gas sensor is exposed to silicone compounds, etc., the gas sensitive part is poisoned and the performance of the gas sensor tends to deteriorate.
　このため、特許文献１（特開平１０－１１５５９７号公報）などでは、ガスを、多孔体を透過させることで、シリコーン系化合物などのガス感応部を被毒する成分を透過しにくくしている。 For this reason, in Patent Document 1 (Japanese Patent Laid-Open No. 10-115597), etc., gas is allowed to permeate through a porous body, thereby making it difficult for components such as silicone-based compounds that poison the gas sensitive portion to permeate.
　発明者の調査によると、特許文献１に開示されている技術では、ガス中の成分を効率よく検知できないことがある。これは、特許文献１の開示のようにセラミックの多孔体基材を細孔制御皮膜で被覆して多孔体を作製すると、多孔体における気孔率が小さくなり、そのため多孔体をガスが透過しにくいためであると考えられる。しかし、ガスを透過しやすくするために細孔径を大きくすると、シリコーン系化合物などの被毒性成分を透過させてしまう。 According to the inventor's research, the technology disclosed in Patent Document 1 may not be able to efficiently detect the components in the gas. This is because, as disclosed in Patent Document 1, when a ceramic porous substrate is coated with a pore control film to produce a porous body, the porosity of the porous body becomes small, and as a result, it is difficult for gas to permeate the porous body. This is thought to be for the sake of However, if the pore size is increased to facilitate gas permeation, toxic components such as silicone compounds will permeate.
　発明者は、活性炭のような、被毒性成分を吸着する吸着剤を使用することも検討したが、吸着剤が被毒性成分を吸着することでその表面が被毒性成分で覆われると、被毒性成分を吸着する性能が低下してしまうため、長期にわたって性能を維持することが難しい。 The inventors have also considered using an adsorbent that adsorbs toxic components, such as activated carbon. It is difficult to maintain the performance over a long period of time because the performance of adsorbing the components deteriorates.
　そこで、発明者は、ガスの透過を確保しながらシリコーン系化合物などの透過を長期にわたって阻害しうるガスフィルタを提供すべく、研究開発を進め、本開示の完成に至った。 Therefore, the inventor has advanced research and development to provide a gas filter that can inhibit permeation of silicone-based compounds and the like for a long period of time while ensuring gas permeation, and has completed the present disclosure.
　なお、本開示は上記の経緯により完成されたものではあるが、上記の経緯は本開示の範囲を制限するものではない。 Although the present disclosure was completed due to the above circumstances, the above circumstances do not limit the scope of the present disclosure.
　以下、図１を参照して、本開示の実施形態について説明する。なお本開示は下記の実施形態に限られない。下記の実施形態は、本開示の様々な実施形態の一部に過ぎず、本開示の目的を達成できれば設計に応じて種々の変更が可能である。 An embodiment of the present disclosure will be described below with reference to FIG. Note that the present disclosure is not limited to the following embodiments. The following embodiments are only a part of various embodiments of the present disclosure, and various modifications are possible according to the design as long as the purpose of the present disclosure can be achieved.
　本実施形態に係るガスフィルタ１は、孔径２ｎｍ未満の細孔を有する分子ふるい層２と、分子ふるい層２に重なる多孔質基材３とを、備える。 The gas filter 1 according to this embodiment includes a molecular sieve layer 2 having pores with a pore size of less than 2 nm, and a porous substrate 3 overlapping the molecular sieve layer 2 .
　なお、多孔質基材３は、分子ふるい層２に直接重なっていてもよく、分子ふるい層２以外の層を介して分子ふるい層２に重なっていてもよい。 The porous substrate 3 may directly overlap the molecular sieve layer 2, or may overlap the molecular sieve layer 2 via a layer other than the molecular sieve layer 2.
　本実施形態によれば、分子ふるい層２を有することで、分子ふるい作用により、シリコーン系化合物などの被毒性成分がガスフィルタ１を透過しにくい。特に、分子ふるい層２の細孔の孔径が２ｎｍ未満であると、代表的な被毒性成分であるシリコーン系化合物のうち多くの分子よりも細孔の孔径が小さくなり、そのため、被毒性成分の透過が効果的に抑制されうる。また、分子ふるい層２は分子ふるい作用によって被毒性成分の透過を阻害するため、吸着剤と比べて、被毒性成分の透過を阻害する作用が経時的に低下しにくい。 According to this embodiment, having the molecular sieve layer 2 makes it difficult for toxic components such as silicone-based compounds to permeate the gas filter 1 due to the molecular sieve action. In particular, when the pore diameter of the pores in the molecular sieve layer 2 is less than 2 nm, the pore diameter of the pores is smaller than that of many molecules of silicone compounds, which are typical poisonous components. Permeation can be effectively suppressed. In addition, since the molecular sieve layer 2 inhibits permeation of toxic components by its molecular sieving action, the effect of inhibiting permeation of toxic components is less likely to decrease over time as compared with the adsorbent.
　また、分子ふるい層２に多孔質基材３が重なっているため、多孔質基材３が分子ふるい層２を支持することができる。そのため、分子ふるい層２の厚みを薄くすることが容易であり、このため分子ふるい層２における細孔の長さを小さくしうる。そのため、分子ふるい層２は、被毒性成分の透過を阻害しながら、ガスの透過は阻害しにくい。 Also, since the porous substrate 3 overlaps the molecular sieve layer 2 , the porous substrate 3 can support the molecular sieve layer 2 . Therefore, it is easy to reduce the thickness of the molecular sieve layer 2, so that the length of pores in the molecular sieve layer 2 can be reduced. Therefore, the molecular sieve layer 2 inhibits the permeation of the poisoning component and hardly inhibits the permeation of the gas.
　このため、本実施形態に係るガスフィルタ１は、ガスの透過を確保しながらガス中のシリコーン系化合物などの透過を長期にわたって阻害しうる。 Therefore, the gas filter 1 according to the present embodiment can inhibit the permeation of silicone-based compounds and the like in the gas for a long period of time while ensuring the permeation of the gas.
　本実施形態に係るガスフィルタ１の、より具体的な構成について説明する。 A more specific configuration of the gas filter 1 according to this embodiment will be described.
　多孔質基材３の材質に特に制限はないが、多孔質基材３の材質は、例えば多孔質セラミック、多孔質ガラス、又は多孔質樹脂である。多孔質基材３の細孔の孔径は、分子ふるい層２の細孔の孔径よりも大きいことが好ましい。この場合、多孔質基材３はガスの透過を特に阻害しにくい。例えば多孔質基材３は、２ｎｍ以上２００ｎｍ以下の孔径の細孔を有する。多孔質基材３の厚みは、多孔質基材３が分子ふるい層２を十分に支持しうる程度の強度を有し、かつ多孔質基材３がガスの透過を阻害しにくいように、適宜調整されることが好ましい。多孔質基材３の厚みは、例えば０．１ｍｍ以上１ｍｍ以下である。 The material of the porous substrate 3 is not particularly limited, but the material of the porous substrate 3 is, for example, porous ceramic, porous glass, or porous resin. The pore size of the pores of the porous substrate 3 is preferably larger than the pore size of the pores of the molecular sieve layer 2 . In this case, the porous substrate 3 is particularly difficult to inhibit gas permeation. For example, the porous substrate 3 has pores with a pore diameter of 2 nm or more and 200 nm or less. The thickness of the porous substrate 3 is appropriately adjusted so that the porous substrate 3 has sufficient strength to support the molecular sieve layer 2 and the porous substrate 3 does not easily inhibit gas permeation. preferably adjusted. The thickness of the porous substrate 3 is, for example, 0.1 mm or more and 1 mm or less.
　なお、多孔質基材３の細孔の孔径は、水銀圧入法によって測定される、平均細孔直径である。 The pore diameter of the pores of the porous substrate 3 is the average pore diameter measured by the mercury porosimetry.
　多孔質基材３の、分子ふるい層２に対向する面は、凹凸状であってもよい（図２参照）。この場合、ガスフィルタ１がガスをより透過させうる。これは、多孔質基材３の形状に沿って分子ふるい層２が凹凸状になり、このため分子ふるい層２の表面積が大きくなるためであると推定される。分子ふるい層２に対向する面が凹凸状であることで、この面についての界面の展開面積比（Ｓｄｒ）が０．１以上であることが好ましい。この場合、ガスフィルタ１がガスを特に透過させうる。この界面の展開面積比（Ｓｄｒ）は、レーザー顕微鏡を用いてこの面の表面粗さを測定した結果から算出できる。 The surface of the porous substrate 3 facing the molecular sieve layer 2 may be uneven (see FIG. 2). In this case, the gas filter 1 is more gas permeable. It is presumed that this is because the molecular sieve layer 2 becomes uneven along the shape of the porous substrate 3, and thus the surface area of the molecular sieve layer 2 increases. Since the surface facing the molecular sieve layer 2 is uneven, it is preferable that the developed area ratio (Sdr) of the interface on this surface is 0.1 or more. In this case, the gas filter 1 can be particularly permeable to gas. The developed area ratio (Sdr) of this interface can be calculated from the result of measuring the surface roughness of this surface using a laser microscope.
　分子ふるい層２は、上述のとおり、孔径２ｎｍ未満の細孔を有する。このため、分子ふるい層２は、分子ふるい作用により、シリコーン系化合物などの被毒性成分を透過させにくい。ガス中に浮遊しうるシリコーン系化合物の径は１から２ｎｍ程度であるため、例えば孔径４ｎｍ程度の細孔を有する多孔質ガラスなどは透過してしまうが、分子ふるい層２の細孔の孔径が２ｎｍ未満であれば、前記のような径を有するシリコーン化合物の透過は十分に阻害されうる。この孔径は１．５ｎｍ以下であればより好ましく、１．２ｎｍ以下であれば更に好ましい。また、細孔の孔径は０．５ｎｍ以上であることが好ましく、０．６ｍｍ以上であればより好ましい。この場合、分子ふるい層２は、ガスの透過を阻害しにくい。 The molecular sieve layer 2 has pores with a pore diameter of less than 2 nm, as described above. For this reason, the molecular sieve layer 2 has a molecular sieve effect, which makes it difficult for poisonous components such as silicone-based compounds to permeate. Since the diameter of the silicone-based compound that can float in the gas is about 1 to 2 nm, it will permeate porous glass having pores with a pore diameter of about 4 nm, for example. If the diameter is less than 2 nm, the permeation of the silicone compound having the above diameter can be sufficiently inhibited. The pore size is more preferably 1.5 nm or less, and even more preferably 1.2 nm or less. Also, the pore size of the pores is preferably 0.5 nm or more, more preferably 0.6 mm or more. In this case, the molecular sieve layer 2 is less likely to inhibit gas permeation.
　なお、分子ふるい層２の細孔の孔径は、窒素吸着測定のｔプロット法により求められる平均細孔径である。 The pore size of the pores of the molecular sieve layer 2 is the average pore size obtained by the t-plot method of nitrogen adsorption measurement.
　分子ふるい層２の厚みは、例えば０．１μｍ以上５μｍ以下である。厚みが０．１μｍ以上であれば、分子ふるい層２によってシリコーン系化合物などの被毒性成分の透過を特に阻害しうる。また、厚みが５μｍ以下であれば、分子ふるい層２がガスの透過を特に阻害しにくい。この厚みは０．２μｍ以上であればより好ましく、０．３μｍ以上であれば更に好ましく、０．５μｍ以上であれば特に好ましい。またこの厚みは２μｍ以下であればより好ましく、１．５μｍ以下であれば更に好ましく、１μｍ以下であれば特に好ましい。 The thickness of the molecular sieve layer 2 is, for example, 0.1 μm or more and 5 μm or less. If the thickness is 0.1 μm or more, the molecular sieve layer 2 can particularly inhibit permeation of toxic components such as silicone compounds. Moreover, if the thickness is 5 μm or less, the molecular sieve layer 2 is particularly unlikely to inhibit gas permeation. This thickness is more preferably 0.2 μm or more, more preferably 0.3 μm or more, and particularly preferably 0.5 μm or more. The thickness is more preferably 2 μm or less, more preferably 1.5 μm or less, and particularly preferably 1 μm or less.
　分子ふるい層２の材質に制限はないが、分子ふるい層２は、シリカ又はポリシロキサンを含むことが好ましい。この場合、分子ふるい層２を、入手容易な材料から、比較的簡便な手法で作製できる。 The material of the molecular sieve layer 2 is not limited, but the molecular sieve layer 2 preferably contains silica or polysiloxane. In this case, the molecular sieve layer 2 can be produced from readily available materials by a relatively simple technique.
　分子ふるい層２は、例えば単一の層であり、すなわち全体にわたってほぼ均質な材質から構成される層である。分子ふるい層２が単一の層であると、多孔質の基材における細孔内面に被覆を施すことで分子ふるいを作製する場合と比較して、基材の細孔径などに応じた成形条件の調整が不要となる。また、ほぼ均質な材料を成形することで分子ふるい層２を作製できるので、細孔内面に被覆を施す場合と比べて、製造プロセス上有利である。このため、分子ふるい層２を容易に作製できる。なお、本実施形態では、分子ふるい層２が単一の層でなくてもよい。 The molecular sieve layer 2 is, for example, a single layer, that is, a layer composed of substantially homogeneous material over its entirety. When the molecular sieve layer 2 is a single layer, molding conditions according to the pore diameter of the substrate, etc., are different compared to the case where the molecular sieve is produced by coating the inner surfaces of the pores in the porous substrate. adjustment becomes unnecessary. Moreover, since the molecular sieve layer 2 can be produced by molding a substantially homogeneous material, it is advantageous in terms of the manufacturing process compared to the case where the inner surfaces of the pores are coated. Therefore, the molecular sieve layer 2 can be easily produced. In addition, in this embodiment, the molecular sieve layer 2 may not be a single layer.
　分子ふるい層２は、適宜の方法で作製される。例えば分子ふるい層２は、ゾルゲル法で作製される。この場合、例えば溶媒に触媒とアルコキシシラン前駆体とを加えて混合することでゾルを調製し、このゾルを多孔質基材３に塗布し、かつ加熱することでゲル化させる。これにより、分子ふるい層２を作製できる。 The molecular sieve layer 2 is produced by an appropriate method. For example, the molecular sieve layer 2 is produced by a sol-gel method. In this case, for example, a sol is prepared by adding and mixing a catalyst and an alkoxysilane precursor to a solvent, and the sol is applied to the porous substrate 3 and heated to gel. Thereby, the molecular sieve layer 2 can be produced.
　分子ふるい層２の欠陥を抑制するためには、好ましくは、まず多孔質基材３を加熱してからゾルを塗布することでゲル化した被膜を作製する。続いて多孔質基材３を再度加熱してから被膜の上にゾルを重ねて塗布することでゲル化させ、被膜の厚みを増大させる。この多孔質基材３の加熱とゾルの塗布とを複数回繰り返してから、被膜を更に加熱することで、分子ふるい層２を作製できる。 In order to suppress defects in the molecular sieve layer 2, it is preferable to first heat the porous substrate 3 and then apply a sol to prepare a gelled coating. Subsequently, the porous substrate 3 is heated again, and the sol is applied over the film to gel it and increase the thickness of the film. The heating of the porous substrate 3 and the application of the sol are repeated several times, and then the coating is further heated to produce the molecular sieve layer 2 .
　溶媒は、例えば水と有機溶媒とを含有する。有機溶媒は、水とアルコキシシラン前駆体との両方と相溶しうる両親性の溶媒であることが好ましく、例えばエタノール等の低級アルコールである。触媒として、適宜の酸触媒又は塩基触媒を使用できる。酸触媒は、例えば塩酸、硫酸、又は硝酸であるが、これらに制限されない。 The solvent contains, for example, water and an organic solvent. The organic solvent is preferably an amphiphilic solvent compatible with both water and the alkoxysilane precursor, such as a lower alcohol such as ethanol. Any suitable acid catalyst or base catalyst can be used as the catalyst. Acid catalysts include, but are not limited to, hydrochloric acid, sulfuric acid, or nitric acid.
　アルコキシシラン前駆体は、例えばテトラメトキシシラン、テトラエトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、ビス（トリエトキシシリル）メタン、１，２－ビス（トリエトキシシリル）エタン、及び１，４－ビス（トリエトキシシリル）ベンゼン等よりなる群から選択される少なくとも一種を含有する。アルコキシシラン前駆体の種類の選択によって、分子ふるい層２の細孔の孔径の制御及び分子ふるい層２の物性の制御が、可能である。 Alkoxysilane precursors include, for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, and 1,4- It contains at least one selected from the group consisting of bis(triethoxysilyl)benzene and the like. By selecting the type of alkoxysilane precursor, it is possible to control the pore size of the pores of the molecular sieve layer 2 and the physical properties of the molecular sieve layer 2 .
　分子ふるい層２の作製方法は、ゾルゲル法には限られず、例えば分子ふるい層２を化学的気相蒸着法で作製してもよい。 The method for producing the molecular sieve layer 2 is not limited to the sol-gel method. For example, the molecular sieve layer 2 may be produced by chemical vapor deposition.
　ガスフィルタ１は、吸着剤層４を更に備えてもよい（図３参照）。吸着剤層４は、吸着剤から作製された層である。吸着剤層４は、分子サイズが比較的小さいなどの理由で分子ふるい層２を透過してしまう被毒性成分を吸着することで、ガスフィルタ１を被毒性成分が透過することを、更に阻害することができる。吸着剤層４は、被毒性成分を吸着しうる適宜の吸着剤から作製される。例えば吸着剤層４は、活性炭、シリカゲル、ゼオライト及び多孔質樹脂よりなる群から選択される少なくとも一種の吸着剤から作製される。吸着剤層４は、例えば吸着剤の粒子を成形して焼結させるなどして作製される。吸着剤層４の厚みは例えば０．５ｍｍ以上５ｍｍ以下である。 The gas filter 1 may further include an adsorbent layer 4 (see FIG. 3). The adsorbent layer 4 is a layer made of adsorbent. The adsorbent layer 4 adsorbs toxic components that permeate the molecular sieve layer 2 due to reasons such as relatively small molecular size, thereby further inhibiting the permeation of the toxic components through the gas filter 1. be able to. The adsorbent layer 4 is made of an appropriate adsorbent capable of adsorbing poisonous components. For example, the adsorbent layer 4 is made of at least one adsorbent selected from the group consisting of activated carbon, silica gel, zeolite and porous resin. The adsorbent layer 4 is produced, for example, by molding and sintering adsorbent particles. The thickness of the adsorbent layer 4 is, for example, 0.5 mm or more and 5 mm or less.
　ガスフィルタ１において、分子ふるい層２と、吸着剤層４とは、この順に、ガスフィルタ１をガスが透過する向きに沿って並んでいることが好ましい。この場合、ガス中の被毒性成分が分子サイズの比較的小さい分子と比較的大きい分子とを含んでいる場合、まず比較的大きい分子の透過が分子ふるい層２で阻害され、続いて比較的小さい分子が吸着剤層４で吸着される。このため、被毒性成分の透過が特に効果的に阻害される。また、吸着剤層４には比較的大きい分子は到達しにくいため、吸着剤層４で吸着される被毒性成分の量を低減できる。このため、吸着剤層４の性能を長期にわたって維持でき、これによりガスフィルタ１の性能を長期にわたって維持できる。 In the gas filter 1, the molecular sieve layer 2 and the adsorbent layer 4 are preferably arranged in this order along the direction in which the gas permeates the gas filter 1. In this case, when the poisonous components in the gas include relatively small molecules and relatively large molecules, the molecular sieve layer 2 first inhibits the permeation of the relatively large molecules, followed by the relatively small molecules. Molecules are adsorbed on the adsorbent layer 4 . For this reason, the permeation of toxic components is particularly effectively inhibited. In addition, since relatively large molecules are less likely to reach the adsorbent layer 4, the amount of poisoning components adsorbed by the adsorbent layer 4 can be reduced. Therefore, the performance of the adsorbent layer 4 can be maintained over a long period of time, and thus the performance of the gas filter 1 can be maintained over a long period of time.
　吸着剤層４は、例えば多孔質基材３に、分子ふるい層２が重なっている面とは反対側の面に重なっている。すなわち、例えば図３に示すように、分子ふるい層２と、多孔質基材３と、吸着剤層４とが、この順に、ガスフィルタ１をガスが透過する向きに沿って並んで、積層している。また、吸着剤層４は、多孔質基材３と分子ふるい層２との間に介在していてもよい。すなわち、分子ふるい層２と、吸着剤層４と、多孔質基材３とが、この順に、ガスフィルタ１をガスが透過する向きに沿って並んで、積層していてもよい。 The adsorbent layer 4 overlaps, for example, the surface of the porous substrate 3 opposite to the surface where the molecular sieve layer 2 overlaps. That is, for example, as shown in FIG. 3, the molecular sieve layer 2, the porous substrate 3, and the adsorbent layer 4 are stacked in this order along the direction of gas permeation through the gas filter 1. ing. Also, the adsorbent layer 4 may be interposed between the porous substrate 3 and the molecular sieve layer 2 . That is, the molecular sieve layer 2, the adsorbent layer 4, and the porous substrate 3 may be stacked in this order along the direction in which gas permeates through the gas filter 1. FIG.
　多孔質基材３がシリコーン系化合物などの被毒性成分を吸着する機能を有していてもよい。その場合、例えば多孔質基材３に吸着剤が含まれていてもよい。多孔質基材３が被毒性成分を吸着する機能を有すれば、多孔質基材３が上記の吸着剤層４と同様に機能して、被毒性成分の透過が効果的に阻害される。この場合、ガスフィルタ１は吸着剤層４を備えなくてもよい。また、多孔質基材３が被毒性成分を吸着する機能を有し、かつガスフィルタ１が吸着剤層４を備えてもよい。その場合、被毒性成分の透過が、より効果的に阻害される。 The porous substrate 3 may have a function of adsorbing poisonous components such as silicone compounds. In that case, for example, the porous substrate 3 may contain an adsorbent. If the porous substrate 3 has a function of adsorbing the poisonous component, the porous substrate 3 functions in the same manner as the adsorbent layer 4 described above, effectively inhibiting the permeation of the poisonous component. In this case, the gas filter 1 may not have the adsorbent layer 4 . Moreover, the porous substrate 3 may have a function of adsorbing the poisonous component, and the gas filter 1 may be provided with the adsorbent layer 4 . In that case, the permeation of toxic components is inhibited more effectively.
　本実施形態に係るガスフィルタ１は、ガスセンサ８用として好適である。ただし、本実施形態に係るガスフィルタ１は、ガスセンサ８用以外にも、その特性を利用できる種々の用途に適用可能である。 The gas filter 1 according to this embodiment is suitable for the gas sensor 8. However, the gas filter 1 according to the present embodiment can be applied to various uses other than the gas sensor 8 in which its characteristics can be used.
　本実施形態に係るガスフィルタ１を備えるガスセンサ８、及びこのガスセンサ８を備えるガス検知装置について、説明する。 A gas sensor 8 provided with the gas filter 1 according to this embodiment and a gas detection device provided with this gas sensor 8 will be described.
　ガスセンサ８は、ガス感応部５と、ガスセンサ室６と、ガス流路７と、ガスフィルタ１とを、備える。ガスセンサ室６には、ガス感応部５が配置されている。ガス流路７は、ガスセンサ室６へ供給されるガスが透過する、ガスセンサ室６に通じる流路である。本実施形態に係るガスフィルタ１は、ガス流路７に設けられ、かつガス感応部５との間にガスセンサ室６内の空間が介在するように配置されている。すなわち、ガスフィルタ１とガス感応部５との間には間隔があいている。 The gas sensor 8 includes a gas sensitive portion 5 , a gas sensor chamber 6 , a gas flow path 7 and a gas filter 1 . A gas sensitive part 5 is arranged in the gas sensor chamber 6 . The gas flow path 7 is a flow path leading to the gas sensor chamber 6 through which the gas supplied to the gas sensor chamber 6 permeates. The gas filter 1 according to this embodiment is provided in the gas flow path 7 and arranged so that the space in the gas sensor chamber 6 intervenes between it and the gas sensing portion 5 . In other words, there is a gap between the gas filter 1 and the gas sensitive part 5 .
　本実施形態に係るガスセンサ８によれば、ガスがガス流路７を通り、ガスフィルタ１を透過してからガスセンサ室６へ供給されて、ガス感応部５に接触する。そのため、ガス中にシリコーン系化合物などの被毒性成分が含まれていても、ガスフィルタ１が被毒性成分の透過を阻害することで、被毒性成分がガス感応部５へ到達しにくい。そのため、ガス感応部５が被毒性成分によって被毒されにくく、このためガス感応部５の性能が長期にわって維持されうる。 According to the gas sensor 8 according to the present embodiment, the gas passes through the gas flow path 7, passes through the gas filter 1, is supplied to the gas sensor chamber 6, and contacts the gas sensing portion 5. Therefore, even if the gas contains a poisonous component such as a silicone-based compound, the gas filter 1 prevents the permeation of the poisonous component, making it difficult for the poisonous component to reach the gas sensing portion 5 . Therefore, the gas sensing portion 5 is less likely to be poisoned by the toxic component, and the performance of the gas sensing portion 5 can be maintained for a long period of time.
　また、ガス感応部５との間にガスセンサ室６内の空間が介在するため、ガス感応部５がガスフィルタ１に直接覆われている場合と比べると、ガス感応部５へのガスの到達が阻害されにくい。そのため、ガス感応部５の感度がガスフィルタ１によって損なわれにくい。 In addition, since the space in the gas sensor chamber 6 is interposed between the gas sensing portion 5 and the gas sensing portion 5, compared with the case where the gas sensing portion 5 is directly covered with the gas filter 1, the gas reaching the gas sensing portion 5 is more difficult. hard to hinder. Therefore, the sensitivity of the gas sensing portion 5 is less likely to be impaired by the gas filter 1 .
　ガス感応部５は、例えばガスに接触するとガス中の成分に応じた出力を生じる適宜のセンサ素子である。出力とは、例えば電気抵抗値等の物性の変化又は電気信号である。ガス感応部５は、例えば半導体式のセンサ素子、接触燃焼式のセンサ素子、又は電気化学式のセンサ素子等である。 The gas sensitive part 5 is, for example, a suitable sensor element that produces an output according to the components in the gas when it comes into contact with the gas. The output is, for example, a change in physical properties such as electrical resistance or an electrical signal. The gas sensitive part 5 is, for example, a semiconductor sensor element, a catalytic combustion sensor element, an electrochemical sensor element, or the like.
　ガスセンサ室６の内部には、上記のとおりガス感応部５が配置されている。ガスセンサ室６の内部には、ガスが供給される空間が形成され、ガス感応部５はこの空間に配置されている。 Inside the gas sensor chamber 6, the gas sensitive part 5 is arranged as described above. A space to which gas is supplied is formed inside the gas sensor chamber 6, and the gas sensitive part 5 is arranged in this space.
　ガス流路７の形態には、ガスセンサ室６の内部に通じ、ガス流路７からガスセンサ室６の内部にガスを供給できるのであれば、特に制限はない。例えばガス流路７はガスセンサ室６に接続されている管路であってもよく、ガスセンサ室６に形成されている開口であってもよい。 The form of the gas channel 7 is not particularly limited as long as it communicates with the inside of the gas sensor chamber 6 and can supply gas from the gas channel 7 to the inside of the gas sensor chamber 6 . For example, the gas flow path 7 may be a pipeline connected to the gas sensor chamber 6 or may be an opening formed in the gas sensor chamber 6 .
　ガスセンサ室６の内部は、ガス流路７に通じている以外は密閉されており、かつガス流路７を流れるガスがすべてガスフィルタ１を透過してからガスセンサ室６に流入するように構成されていることが好ましい。そのためには、例えばガスフィルタ１は、ガス流路７を塞ぐように、すなわちガス流路７をガスの流通する向きの上流側と下流側とに仕切るように、設けられる。この場合、特にガス感応部５によるガス検知の過程でガスセンサ室６内のガスの体積が小さくなる場合には、ガスセンサ室６の内部と外部との間で圧力差が生じ、このためガスフィルタ１を通じたガスセンサ室６の内部へのガスの流入が促進される。このため、ガス検知の効率が高くなりうる。ガス感応部５によるガス検知の過程でガスセンサ室６内のガスの体積が小さくなる場合とは、例えばガス感応部５が一酸化炭素検出用の接触燃焼式のセンサ素子である場合であり、このとき、２分子の一酸化炭素と１分子の酸素とが反応して２分子の二酸化炭素が生成するためにガスの体積が小さくなる。半導体式のセンサ素子、電気化学式のセンサ素子である場合にも、同様に化学反応によりガスの体積が小さくなって、ガスの流入が促進されうる。 The interior of the gas sensor chamber 6 is hermetically sealed except for communicating with the gas flow path 7 , and is constructed so that all the gas flowing through the gas flow path 7 passes through the gas filter 1 before flowing into the gas sensor chamber 6 . preferably. For this purpose, for example, the gas filter 1 is provided so as to close the gas flow path 7, that is, to divide the gas flow path 7 into an upstream side and a downstream side in the gas flow direction. In this case, especially when the volume of gas in the gas sensor chamber 6 decreases during the process of gas detection by the gas sensitive part 5, a pressure difference occurs between the inside and the outside of the gas sensor chamber 6, causing the gas filter 1 to The inflow of gas into the gas sensor chamber 6 through is promoted. Therefore, the efficiency of gas detection can be increased. The case where the volume of gas in the gas sensor chamber 6 decreases during the process of gas detection by the gas sensing section 5 is, for example, the case where the gas sensing section 5 is a catalytic combustion type sensor element for detecting carbon monoxide. When two molecules of carbon monoxide react with one molecule of oxygen to produce two molecules of carbon dioxide, the volume of the gas decreases. In the case of a semiconductor type sensor element or an electrochemical type sensor element, the volume of gas is similarly reduced by a chemical reaction, and the inflow of gas can be promoted.
　ガスフィルタ１の平面視面積に対する、ガスセンサ室６の空間の容積の割合は、できるだけ小さいことが好ましく、特に２ｍｍ３／ｍｍ２以下であることが好ましい。なお、平面視とは、ガスフィルタ１をその厚み方向に見ることをいう。この場合、ガスセンサ８を用いてガス中の検知対象の成分を検知する際の応答性が高くなりうる。これは、前記の割合が小さいほど、ガスフィルタ１と通じてガスをガスセンサ室６内に供給した場合の、ガスセンサ室６内での検知対象の成分の濃度が上昇しやすいためであると、推察される。 The ratio of the volume of the space of the gas sensor chamber 6 to the planar view area of the gas filter 1 is preferably as small as possible, particularly preferably 2 mm 3 /mm 2 or less. In addition, planar view means seeing the gas filter 1 in the thickness direction. In this case, the gas sensor 8 can be more responsive when detecting the component to be detected in the gas. It is speculated that this is because the smaller the ratio, the higher the concentration of the component to be detected in the gas sensor chamber 6 when the gas is supplied into the gas sensor chamber 6 through the gas filter 1. be done.
　本実施形態に係るガス検知装置は、本実施形態に係るガスセンサ８と、ガスセンサ８におけるガス感応部５の出力を検出する検出部とを備える。検出部は、例えばガス感応部５の出力に基づいてガス中の測定対象の成分を検知し、或いは更にこの成分のガス中の濃度を測定する、検知用回路である。ガス検知装置は、例えばガス警報器として構成される。 The gas detection device according to this embodiment includes the gas sensor 8 according to this embodiment and a detection section that detects the output of the gas sensing section 5 in the gas sensor 8 . The detection section is a detection circuit that detects the component to be measured in the gas based on the output of the gas sensing section 5, for example, or further measures the concentration of this component in the gas. The gas detection device is configured, for example, as a gas alarm.
　以下、本実施形態の、具体的な実施例について説明する。なお、本実施形態は、下記の実施例のみに制限されるものではない。 Specific examples of the present embodiment will be described below. In addition, this embodiment is not limited only to the following examples.
　１．ガスフィルタ１の作製
　エタノール１０ｍＬ、水２．３３ｍＬ、０．１Ｍ塩酸水溶液２．００ｍＬと混合し、得られた混合液に１，２－ビス（トリエトキシシリル）エタン０．７３ｍＬを加えてから、室温で１時間攪拌することで、ゾルを調製した。 1. Preparation of gas filter 1 Mix with 10 mL of ethanol, 2.33 mL of water, and 2.00 mL of 0.1 M aqueous hydrochloric acid solution, add 0.73 mL of 1,2-bis(triethoxysilyl)ethane to the resulting mixture, A sol was prepared by stirring at room temperature for 1 hour.
　多孔質基材３として、平均細孔径５０ｎｍ、厚さ１ｍｍの多孔質ガラス基材を用意した。この多孔質基材３を１８０℃に加熱してから、多孔質基材３の上にゾルを塗布することで、ゲル化した被膜を作製した。続いて、多孔質基材３を１８０℃に加熱してから、被膜の上にゾルを塗布してゲル化させることで、ゲル化した被膜の厚みを増大させた。この多孔質基材３の加熱とゾルの塗布とを１０回繰り返してから、ゲル化した被膜を１８０℃で２時間加熱した。これにより、分子ふるい層２を作製し、分子ふるい層２と多孔質基材３とを備えるガスフィルタ１を得た。このガスフィルタ１の断面を撮影した走査電子顕微鏡写真を、図４に示す。 A porous glass substrate having an average pore diameter of 50 nm and a thickness of 1 mm was prepared as the porous substrate 3 . After heating the porous substrate 3 to 180° C., the sol was applied on the porous substrate 3 to prepare a gelled film. Subsequently, after heating the porous substrate 3 to 180° C., the coating was coated with a sol and gelled, thereby increasing the thickness of the gelled coating. After repeating the heating of the porous substrate 3 and the application of the sol 10 times, the gelled coating was heated at 180° C. for 2 hours. Thus, the molecular sieve layer 2 was produced, and the gas filter 1 including the molecular sieve layer 2 and the porous substrate 3 was obtained. A scanning electron microscope photograph of the cross section of this gas filter 1 is shown in FIG.
　このガスフィルタ１における分子ふるい層２の厚みは０．９μｍであった。また、この分子ふるい層２の、窒素吸着測定のｔプロット法により求めた平均細孔径は、０．８５ｎｍであった。 The thickness of the molecular sieve layer 2 in this gas filter 1 was 0.9 μm. The average pore diameter of this molecular sieve layer 2 obtained by the t-plot method of nitrogen adsorption measurement was 0.85 nm.
　２．ガス透過性評価試験
　次のようにして試験用のガスセンサ８を作製した。プリント基板上にガス感応部５としてフィガロ技研株式会社製のＴＧＳ８１００を配置し、その上方にガスフィルタ１を配置した。ガスフィルタ１とプリント配線板の間にＯ－リングを介在させることで、ガス感応部５の周りの空間を外部から密閉した。これにより、平面視面積２００ｍｍ２、高さ１ｍｍの空間内にガス感応部５を配置し、かつこの空間を、上面全体がガスフィルタ１で閉塞されている以外は、密閉した。 2. Gas Permeability Evaluation Test A gas sensor 8 for testing was produced as follows. TGS8100 manufactured by Figaro Engineering Co., Ltd. was arranged as the gas sensitive part 5 on the printed circuit board, and the gas filter 1 was arranged above it. By interposing an O-ring between the gas filter 1 and the printed wiring board, the space around the gas sensitive part 5 was sealed from the outside. As a result, the gas sensing part 5 was arranged in a space having a planar view area of 200 mm 2 and a height of 1 mm, and this space was sealed except for the entire top surface of which was blocked by the gas filter 1 .
　乾燥空気に一酸化炭素を濃度２５ｐｐｍとなるように混入したガスを、ガスフィルタ１に向けて吹き付けることで、ガスをガスフィルタ１を介してガスセンサ８の内部に注入した。このときのガス感応部５の出力（電気抵抗値の経時変化）を測定した。 By blowing dry air mixed with carbon monoxide to a concentration of 25 ppm toward the gas filter 1 , the gas was injected into the gas sensor 8 through the gas filter 1 . The output of the gas sensitive part 5 at this time (change in electrical resistance with time) was measured.
　また、このガスセンサ８からガスフィルタ１を取り外した状態で、乾燥空気に一酸化炭素を濃度２５ｐｐｍとなるように混入したガスを、ガス感応部５に直接吹き付けた。このときのガス感応部５の出力（電気抵抗値の経時変化）も測定した。 In addition, with the gas filter 1 removed from the gas sensor 8 , dry air mixed with carbon monoxide at a concentration of 25 ppm was directly blown onto the gas sensing part 5 . The output of the gas sensitive part 5 at this time (change in electrical resistance over time) was also measured.
　図５に、ガス感応部５の出力の測定結果を示す。図５の縦軸はガス感応部５の電気抵抗値を示し、横軸は経過時間を示す。図中の「Ａ」の実線はガスをガスフィルタ１を介してガスセンサ８の内部に注入した場合の結果を、「Ｂ」の破線はガスをガス感応部５に直接吹き付けた場合の結果を、それぞれ示す。「注入開始」はガスの注入を開始した時点を示し、「注入終了」はガスの注入を終了した時点を示す。 　Fig. 5 shows the measurement results of the output of the gas sensitive part 5. The vertical axis of FIG. 5 indicates the electrical resistance value of the gas sensing portion 5, and the horizontal axis indicates the elapsed time. In the figure, the solid line "A" shows the results when the gas is injected into the gas sensor 8 through the gas filter 1, and the dashed line "B" shows the results when the gas is directly sprayed onto the gas sensitive part 5. each shown. "Injection start" indicates the time point at which gas injection is started, and "Injection end" indicates the time point at which gas injection is finished.
　図５に示す結果によると、ガスをガスフィルタ１を介してガスセンサ８の内部に注入した場合の電気抵抗値の変化量は、ガスをガス感応部５に直接吹き付けた場合と同程度であり、このためガスフィルタ１を使用したことによる感度の低下は認められない。また、ガスをガス感応部５に直接吹き付けた場合は、ガスの注入開始から１５秒程度で電気抵抗値が下げ止まったのに対し、ガスをガスフィルタ１を介してガスセンサ８の内部に注入した場合はガス注入開始から２２秒程度で電気抵抗値が下げ止まった。このため、ガスフィルタ１を用いたことによる応答の遅れは７秒程度に過ぎず、ガスフィルタ１による応答性への影響は十分に小さいと評価できる。 According to the results shown in FIG. 5, the amount of change in electrical resistance when gas is injected into the inside of the gas sensor 8 through the gas filter 1 is about the same as when the gas is directly blown onto the gas sensitive part 5. Therefore, no decrease in sensitivity due to the use of the gas filter 1 is observed. Further, when the gas was directly blown onto the gas sensing part 5, the electrical resistance value stopped decreasing about 15 seconds after the start of gas injection. In this case, the electric resistance value stopped decreasing about 22 seconds after the start of gas injection. Therefore, the delay in response due to the use of the gas filter 1 is only about 7 seconds, and it can be evaluated that the effect of the gas filter 1 on the responsiveness is sufficiently small.
　したがって、ガスフィルタ１は、ガスの透過を阻害しにくいといえる。 Therefore, it can be said that the gas filter 1 is less likely to inhibit gas permeation.
　３．被毒性成分の透過性評価試験
　容積２００ｃｍ３、開口の面積２００ｍｍ２の二つの容器を用意し、これらの容器の開口同士をガスフィルタ１を介して向かい合わせて接続した。ガスフィルタ１と各開口の縁との間はゴムパッキンで閉塞した。デカメチルシクロペンタシロキサンを容器に入れた状態でバブリングすることでシロキサンガスを発生させ、このシロキサンガスを一方の容器内にポンプで注入した。もう一方の容器をマルチガスモニタに接続し、この容器内のシロキサンガス濃度を測定した。 3. Toxic Component Permeability Evaluation Test Two containers having a volume of 200 cm 3 and an opening area of 200 mm 2 were prepared, and the openings of these containers were connected to face each other via a gas filter 1 . A gap between the gas filter 1 and the edge of each opening was closed with a rubber packing. A siloxane gas was generated by bubbling decamethylcyclopentasiloxane in a container, and this siloxane gas was pumped into one of the containers. The other container was connected to a multi-gas monitor, and the siloxane gas concentration in this container was measured.
　また、ガスフィルタ１を用いずに二つの容器を接続した場合にも、上記と同じ試験を行った。また、参考として、ガスフィルタ１に代えて、平均細孔径４ｎｍ、厚み１ｍｍの多孔質ガラス基材を用いた場合にも、上記と同じ試験を行った。 Also, when two containers were connected without using the gas filter 1, the same test as above was conducted. As a reference, the same test as above was also conducted when a porous glass substrate having an average pore size of 4 nm and a thickness of 1 mm was used in place of the gas filter 1 .
　その結果を、図６に示す。縦軸はシロキサン濃度の測定結果を示し、横軸はシロキサンガスの注入を開始した時点からの経過時間を示す。図中の「Ａ」の実線はガスフィルタ１を用いた場合の結果を示し、「Ｂ」の破線はガスフィルタ１を用いない場合の結果を示し、「Ｃ」の破線はガスフィルタ１に代えて平均細孔径４ｎｍ、厚み１ｍｍの多孔質ガラス基材を用いた場合の結果を示す。 The results are shown in Figure 6. The vertical axis indicates the measurement result of the siloxane concentration, and the horizontal axis indicates the elapsed time from the start of injection of the siloxane gas. In the figure, the solid line "A" shows the results when the gas filter 1 is used, the dashed line "B" shows the results when the gas filter 1 is not used, and the dashed line "C" shows the results when the gas filter 1 is used instead. shows the results when using a porous glass substrate having an average pore diameter of 4 nm and a thickness of 1 mm.
　図６に示す結果によると、ガスフィルタ１を用いた場合にはシロキサン濃度の測定値は殆ど上昇しなかったのに対し、ガスフィルタ１を用いない場合にはシロキサン濃度の測定値は急激に２００ｐｐｍまで上昇した。ガスフィルタ１に代えて平均細孔径４ｎｍ、厚み１ｍｍの多孔質ガラス基材を用いた場合にはシロキサン濃度上昇はある程度抑制されるものの、徐々に上昇した。 According to the results shown in FIG. 6, when the gas filter 1 was used, the measured value of the siloxane concentration hardly increased, whereas when the gas filter 1 was not used, the measured value of the siloxane concentration suddenly increased to 200 ppm. rose to When a porous glass substrate having an average pore diameter of 4 nm and a thickness of 1 mm was used in place of the gas filter 1, the increase in siloxane concentration was suppressed to some extent, but gradually increased.
　したがって、ガスフィルタ１は、シロキサンガスを透過させにくいといえる。 Therefore, it can be said that the gas filter 1 is difficult to permeate the siloxane gas.
　以上の実施形態及び実施例から明らかなように、本開示の第一の態様に係るガスフィルタ（１）は、孔径２ｎｍ未満の細孔を有する分子ふるい層（２）と、分子ふるい層（２）に重なる多孔質基材（３）とを、備える。 As is clear from the above embodiments and examples, the gas filter (1) according to the first aspect of the present disclosure includes a molecular sieve layer (2) having pores with a pore size of less than 2 nm, and a molecular sieve layer (2 ) overlying the porous substrate (3).
　第一の態様によると、ガスフィルタ（１）によって、ガスの透過を確保しながらシリコーン系化合物などの透過を長期にわたって阻害しうる。 According to the first aspect, the gas filter (1) can inhibit permeation of silicone-based compounds and the like for a long period of time while ensuring gas permeation.
　本開示の第二の態様に係るガスフィルタ（１）では、第一の態様において、分子ふるい層（２）は、単一の層である。 In the gas filter (1) according to the second aspect of the present disclosure, in the first aspect, the molecular sieve layer (2) is a single layer.
　第二の態様によると、分子ふるい層（２）を容易に作製しうる。 According to the second aspect, the molecular sieve layer (2) can be easily produced.
　本開示の第三の態様に係るガスフィルタ（１）では、第一又は第二の態様において、分子ふるい層（２）の細孔の孔径は、０．５ｎｍ以上１．５ｎｍ以下である。 In the gas filter (1) according to the third aspect of the present disclosure, in the first or second aspect, the pore size of the pores of the molecular sieve layer (2) is 0.5 nm or more and 1.5 nm or less.
　第三の態様によると、ガスフィルタ（１）によって、シリコーン系化合物の透過をより効果的に阻害しうる。 According to the third aspect, the gas filter (1) can more effectively inhibit permeation of silicone compounds.
　本開示の第四の態様に係るガスフィルタ（１）では、第一から第三のいずれか一の態様において、分子ふるい層（２）は、シリカ又はポリシロキサンを含む。 In the gas filter (1) according to the fourth aspect of the present disclosure, in any one of the first to third aspects, the molecular sieve layer (2) contains silica or polysiloxane.
　第四の態様によると、ガスフィルタ（１）によって、シリコーン系化合物の透過をより効果的に阻害しうる。 According to the fourth aspect, the gas filter (1) can more effectively inhibit permeation of silicone compounds.
　本開示の第五の態様に係るガスフィルタ（１）では、第一から第四のいずれか一の態様において、多孔質基材（３）の、分子ふるい層（２）と対向する面は、凹凸状である。 In the gas filter (1) according to the fifth aspect of the present disclosure, in any one of the first to fourth aspects, the surface of the porous substrate (3) facing the molecular sieve layer (2) is It is uneven.
　第五の態様によると、ガスフィルタ（１）は、ガスをより透過させやすく、かつシリコーン系化合物などの透過をより効果的に阻害しうる。 According to the fifth aspect, the gas filter (1) is more permeable to gas and more effectively inhibits the permeation of silicone-based compounds and the like.
　本開示の第六の態様に係るガスフィルタ（１）は、第一から第五のいずれか一の態様において、吸着剤層（４）を更に備える。 The gas filter (1) according to the sixth aspect of the present disclosure, in any one of the first to fifth aspects, further comprises an adsorbent layer (4).
　第六の態様によると、ガスフィルタ（１）は、シリコーン系化合物などの透過をより効果的に阻害しうる。 According to the sixth aspect, the gas filter (1) can more effectively inhibit permeation of silicone compounds and the like.
　本開示の第七の態様に係るガスフィルタ（１）では、第六の態様において、分子ふるい層（２）と、吸着剤層（４）とは、この順に、ガスフィルタ（１）をガスが透過する向きに沿って並んでいる。 In the gas filter (1) according to the seventh aspect of the present disclosure, in the sixth aspect, the molecular sieve layer (2) and the adsorbent layer (4) are arranged in this order so that the gas filter (1) is Lined up along the direction of transmission.
　第七の態様によると、ガスフィルタ（１）によって、シリコーン系化合物などの透過をより長期にわたって阻害しうる。 According to the seventh aspect, the gas filter (1) can inhibit permeation of silicone-based compounds and the like for a longer period of time.
　本開示の第八の態様に係るガスフィルタ（１）では、第六又は第七の態様において、吸着剤層（４）は、活性炭、シリカゲル、ゼオライト及び多孔質樹脂よりなる群から選択される少なくとも一種を含有する。 In the gas filter (1) according to the eighth aspect of the present disclosure, in the sixth or seventh aspect, the adsorbent layer (4) is at least selected from the group consisting of activated carbon, silica gel, zeolite and porous resin. contains one
　第八の態様によると、ガスフィルタ（１）は、シリコーン系化合物などの透過をより効果的に阻害しうる。 According to the eighth aspect, the gas filter (1) can more effectively inhibit permeation of silicone compounds and the like.
　本開示の第九の態様に係るガスフィルタ（１）は、第一から第八のいずれか一の態様において、ガスセンサ（８）用である。 A gas filter (1) according to a ninth aspect of the present disclosure is for a gas sensor (8) in any one of the first to eighth aspects.
　第九の態様によると、ガスフィルタ（１）によって、シリコーン系化合物などによる被毒によるガスセンサ（８）の性能低下を起こしにくくでき、かつガスフィルタ（１）はガスセンサ（８）の感度及び応答性を低下させにくい。 According to the ninth aspect, the gas filter (1) makes it difficult for the performance of the gas sensor (8) to deteriorate due to poisoning by silicone-based compounds, etc., and the gas filter (1) provides sensitivity and responsiveness of the gas sensor (8). difficult to reduce.
　本開示の第十の態様に係るガスセンサ（８）は、ガス感応部（５）と、ガス感応部（５）が配置されるガスセンサ室（６）と、ガスセンサ室（６）へ供給されるガスが流れるガス流路（７）と、ガス流路（７）に設けられ、かつガス感応部（５）との間にガスセンサ室（６）内の空間が介在するように配置されている、第一から第九のいずれか一の態様に係るガスフィルタ（１）とを備える。 A gas sensor (8) according to a tenth aspect of the present disclosure comprises a gas sensing portion (5), a gas sensor chamber (6) in which the gas sensing portion (5) is arranged, and a gas supplied to the gas sensor chamber (6). and a gas sensor chamber (6) provided in the gas flow path (7) and arranged so that the space in the gas sensor chamber (6) is interposed between the gas sensing part (5) and the gas sensor chamber (6). A gas filter (1) according to any one of the first to ninth aspects.
　第十の態様によると、ガスフィルタ（１）によって、シリコーン系化合物などによる被毒によるガスセンサ（８）の性能低下を起こしにくくでき、かつガスフィルタ（１）はガスセンサ（８）の感度及び応答性を低下させにくい。 According to the tenth aspect, the gas filter (1) makes it difficult for the performance of the gas sensor (8) to deteriorate due to poisoning by a silicone-based compound or the like, and the gas filter (1) provides the sensitivity and responsiveness of the gas sensor (8). difficult to reduce.
　本開示の第十一の態様に係るガスセンサ（８）では、第十の態様において、ガスセンサ室（６）は、ガス流路（７）に通じている以外は密閉され、ガス流路（７）は、ガス流路（７）を流れるガスがすべてガスフィルタ（１）を透過してからガスセンサ室（６）に流入するように構成されている。 In the gas sensor (8) according to the eleventh aspect of the present disclosure, in the tenth aspect, the gas sensor chamber (6) is sealed except for communicating with the gas flow path (7), and the gas flow path (7) is configured so that all the gas flowing through the gas flow path (7) passes through the gas filter (1) before flowing into the gas sensor chamber (6).
　第十一の態様によると、ガスフィルタ（１）はガスセンサ（８）の応答性を、より低下させにくい。 According to the eleventh aspect, the gas filter (1) is less likely to reduce the responsiveness of the gas sensor (8).
　本開示の第十二の態様に係るガスセンサ（８）では、第十又は十一の態様において、ガスフィルタ（１）の平面視面積に対する、前記ガスセンサ室（６）の空間の容積の割合は、２ｍｍ３／ｍｍ２以下である。 In the gas sensor (8) according to the twelfth aspect of the present disclosure, in the tenth or eleventh aspect, the ratio of the volume of the space of the gas sensor chamber (6) to the planar view area of the gas filter (1) is It is 2 mm 3 /mm 2 or less.
　第十二の態様によると、ガスフィルタ（１）はガスセンサ（８）の応答性を、より低下させにくい。 According to the twelfth aspect, the gas filter (1) is less likely to reduce the responsiveness of the gas sensor (8).
　本開示の第十三の態様に係るガス検知装置は、第十から第十二のいずれか一の態様に係るガスセンサ（８）と、ガスセンサ（８）におけるガス感応部（５）の出力を検出する検出部とを備える。 A gas detection device according to a thirteenth aspect of the present disclosure includes a gas sensor (8) according to any one of the tenth to twelfth aspects, and detecting an output of a gas sensitive part (5) in the gas sensor (8). and a detection unit.
　第十三の態様によると、ガスフィルタ（１）によって、シリコーン系化合物などによる被毒によるガス検知装置の性能低下を起こしにくくでき、かつガスフィルタ（１）はガス検知装置の感度及び応答性を低下させにくい。 According to the thirteenth aspect, the gas filter (1) makes it difficult for the performance of the gas detection device to deteriorate due to poisoning by a silicone compound or the like, and the gas filter (1) improves the sensitivity and responsiveness of the gas detection device. hard to lower.
　１　　ガスフィルタ
　２　　分子ふるい層
　３　　多孔質基材
　４　　吸着剤層
　５　　ガス感応部
　６　　ガスセンサ室
　７　　ガス流路
　８　　ガスセンサ REFERENCE SIGNS LIST 1 gas filter 2 molecular sieve layer 3 porous substrate 4 adsorbent layer 5 gas sensitive part 6 gas sensor chamber 7 gas channel 8 gas sensor

Claims (13)

  1. 孔径２ｎｍ未満の細孔を有する分子ふるい層と、
    前記分子ふるい層に重なる多孔質基材とを、備える、
    ガスフィルタ。     a molecular sieve layer having pores with a pore size of less than 2 nm;
    a porous substrate overlying the molecular sieve layer;
    gas filter.
  2. 前記分子ふるい層は、単一の層である、
    請求項１に記載のガスフィルタ。     the molecular sieve layer is a single layer,
    A gas filter according to claim 1 .
  3. 前記細孔の前記孔径は、０．５ｎｍ以上１．５ｎｍ以下である、
    請求項１又は２に記載のガスフィルタ。     The pore diameter of the pores is 0.5 nm or more and 1.5 nm or less,
    A gas filter according to claim 1 or 2.
  4. 前記分子ふるい層は、シリカ又はポリシロキサンを含む、
    請求項１から３のいずれか一項に記載のガスフィルタ。     the molecular sieve layer comprises silica or polysiloxane;
    A gas filter according to any one of claims 1 to 3.
  5. 前記多孔質基材の、前記分子ふるい層と対向する面は、凹凸状である、
    請求項１から４のいずれか一項に記載のガスフィルタ。     The surface of the porous substrate facing the molecular sieve layer is uneven,
    A gas filter according to any one of claims 1 to 4.
  6. 吸着剤層を更に備える、
    請求項１から５のいずれか一項に記載のガスフィルタ。     further comprising an adsorbent layer;
    6. A gas filter according to any one of claims 1-5.
  7. 前記分子ふるい層と、前記吸着剤層とは、この順に、前記ガスフィルタをガスが透過する向きに沿って並んでいる、
    請求項６に記載のガスフィルタ。     The molecular sieve layer and the adsorbent layer are arranged in this order along the direction of gas permeation through the gas filter,
    A gas filter according to claim 6 .
  8. 前記吸着剤層は、活性炭、シリカゲル、ゼオライト及び多孔質樹脂よりなる群から選択される少なくとも一種を含有する、
    請求項６又は７に記載のガスフィルタ。     The adsorbent layer contains at least one selected from the group consisting of activated carbon, silica gel, zeolite and porous resin,
    A gas filter according to claim 6 or 7.
  9. ガスセンサ用である、
    請求項１から８のいずれか一項に記載のガスフィルタ。     for gas sensors,
    9. A gas filter according to any one of claims 1-8.
  10. ガス感応部と、
    前記ガス感応部が配置されるガスセンサ室と、
    前記ガスセンサ室へ供給されるガスが流れるガス流路と、
    前記ガス流路に設けられ、かつ前記ガス感応部との間に前記ガスセンサ室内の空間が介在するように配置されている、請求項１から９のいずれか一項に記載のガスフィルタとを備える、
    ガスセンサ。     a gas sensitive part;
    a gas sensor chamber in which the gas sensitive part is arranged;
    a gas flow path through which gas supplied to the gas sensor chamber flows;
    The gas filter according to any one of claims 1 to 9, which is provided in the gas flow path and arranged so that the space in the gas sensor chamber is interposed between the gas sensor and the gas sensing portion. ,
    gas sensor.
  11. 前記ガスセンサ室は、前記ガス流路に通じている以外は密閉され、前記ガス流路は、前記ガス流路を流れるガスがすべて前記ガスフィルタを透過してから前記ガスセンサ室に流入するように構成されている、
    請求項１０に記載のガスセンサ。     The gas sensor chamber is sealed except for communicating with the gas flow path, and the gas flow path is configured so that all the gas flowing through the gas flow path passes through the gas filter before flowing into the gas sensor chamber. has been
    The gas sensor according to claim 10.
  12. 前記ガスフィルタの平面視面積に対する、前記ガスセンサ室の空間の容積の割合は、２ｍｍ３／ｍｍ２以下である、
    請求項１０又は１１に記載のガスセンサ。     The ratio of the volume of the space of the gas sensor chamber to the planar view area of the gas filter is 2 mm 3 /mm 2 or less.
    The gas sensor according to claim 10 or 11.
  13. 請求項１０から１２のいずれか一項に記載のガスセンサと、
    前記ガスセンサにおける前記ガス感応部の出力を検出する検出部とを備える、
    ガス検知装置。     a gas sensor according to any one of claims 10 to 12;
    a detection unit that detects the output of the gas sensing unit in the gas sensor,
    Gas detector.
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