JP2021128124A - Gas detector and ozone gas removal filter - Google Patents

Abstract

To provide a gas detector that can suppress interference of an ozone gas and has higher selectivity of a detection target gas, and an ozone gas removal filter for removing an ozone gas.SOLUTION: A gas detector of the present invention is a gas detector D including: a gas sensor 1 for detecting a detection target gas in a measurement target gas; and an ozone gas removal filter O being arranged above the gas sensor 1, for removing an ozone gas in the measurement target gas. The ozone gas removal filter O has a filter member including a material with smaller gas adsorption than that of an active carbon, silica gel, or zeolite in a surface.SELECTED DRAWING: Figure 1

Description

The present invention relates to a gas detector and an ozone gas removal filter.

The permissible concentration of toxic gas such as diboran gas is set by the High Pressure Gas Safety Act. For example, diboran gas is set to 0.1 ppm. Therefore, in a working environment where toxic gas is used, it is necessary to control the concentration of toxic gas below the permissible concentration. For that purpose, a gas detector equipped with a gas sensor having a sensitivity equal to or lower than the permissible concentration of toxic gas is required.

As a gas sensor for detecting a gas to be detected such as a low-concentration toxic gas, for example, a constant potential electrolytic gas sensor as disclosed in Patent Document 1 is used. The constant potential electrolytic gas sensor detects the detection target gas by utilizing the electrochemical reaction of the detection target gas in the electrolytic solution. The constant potential electrolytic gas sensor has high sensitivity and can detect the detection target gas having a concentration of ppb level.

Japanese Unexamined Patent Publication No. 2014-98679

However, when trying to detect the detection target gas with a ppb level concentration using an electrochemical gas sensor such as a constant potential electrolysis type, ozone gas is present in the atmosphere at almost the same level concentration, so it is related to the detection target gas. An ozone gas signal with a non-negligible intensity is measured with respect to the intensity of the signal. Therefore, when detecting a low-concentration detection target gas, it is necessary to suppress interference of ozone gas and improve the selectivity of the detection target gas.

For example, in a gas detector equipped with an electrochemical gas sensor, a gas filter containing activated carbon may be used upstream of the gas sensor in order to filter interfering gases other than the gas to be detected. However, the gas filter containing activated carbon has high gas adsorption property, and adsorbs not only the interference gas but also the detection target gas. Therefore, even if the gas detector uses a gas filter containing activated carbon, the sensitivity to ozone gas is lowered and the sensitivity of the detection target gas is also lowered, so that the selectivity of the detection target gas cannot be improved. As described above, there is no effective ozone gas removal filter arranged particularly upstream of the gas sensor, and it is difficult to suppress the interference of ozone gas and improve the selectivity of the detection target gas in the gas detector.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a gas detector that suppresses interference by ozone gas and enhances the selectivity of the detection target gas, and an ozone gas removal filter for removing ozone gas. do.

The gas detector of the present invention includes a gas sensor for detecting the detection target gas contained in the measurement target gas, and an ozone gas removal filter arranged upstream of the gas sensor for removing the ozone gas contained in the measurement target gas. The ozone gas removal filter is characterized by including a filter member having a surface containing a material having a gas adsorption property lower than that of activated charcoal, silica gel or zeolite.

Further, the ozone gas removal filter includes a filter member accommodating portion including an inlet and an outlet, and the filter member has the filter so that the surface of the filter member is inclined with respect to an axis connecting the inlet and the outlet. It is preferably housed in the member housing part.

Further, the material is preferably a fluororesin.

Further, it is preferable that the gas sensor is an electrochemical gas sensor and the detection target gas is a special high-pressure gas containing monosilane, disilane, arsine, phosphine, diborane, monogerman or hydrogen selenide.

Further, the gas detector preferably includes a sheet having water repellency and gas permeability.

Further, the gas detector preferably includes a gas suction device that sucks the gas to be measured.

The ozone gas removal filter of the present invention is an ozone gas removal filter for removing the ozone gas contained in the measurement target gas, which is arranged upstream of the gas sensor for detecting the detection target gas contained in the measurement target gas. The ozone gas removal filter is characterized by comprising a filter member having a surface containing a material having a lower gas adsorption property than activated carbon, silica gel or zeolite.

According to the present invention, it is possible to provide a gas detector that suppresses interference by ozone gas and enhances the selectivity of the detection target gas, and an ozone gas removal filter for removing ozone gas.

It is the schematic of the gas detector which concerns on one Embodiment of this invention. It is sectional drawing of the electrochemical type gas sensor included in the gas detector of FIG. It is sectional drawing of the electrochemical type gas sensor of the modification included in the gas detector of FIG. It is an exploded view of the ozone gas removal filter included in the gas detector of FIG. It is sectional drawing of the filter member accommodating part accommodating a filter member.

Hereinafter, the gas detector and the ozone gas removal filter according to the embodiment of the present invention will be described with reference to the accompanying drawings. However, the embodiment shown below is an example, and the gas detector and the ozone gas removal filter of the present invention are not limited to the following examples.

<Gas detector>
As shown in FIG. 1, the gas detector D of the present embodiment is arranged upstream of the gas sensor 1 for detecting the detection target gas contained in the measurement target gas and the gas sensor 1 and is included in the measurement target gas. It is provided with an ozone gas removal filter O for removing ozone gas. As described in detail below, the gas detector D removes at least a part of the ozone gas contained in the measurement target gas by the ozone gas removal filter O, and the detection target contained in the measurement target gas from which at least a part of the ozone gas has been removed. The gas is detected by the gas sensor 1. By providing the ozone gas removal filter O upstream of the gas sensor 1, the gas detector D can suppress interference due to ozone gas and enhance the selectivity of the detection target gas. In the embodiment shown below, the gas sensor 1 is an electrochemical gas sensor, but the gas sensor 1 is not limited to the electrochemical gas sensor, and has the same level as the ozone gas concentration in the atmosphere, such as an ultra-high purity hydrogen sensor and an odor sensor. A gas sensor that detects the gas whose concentration is to be detected can be adopted. The detection target gas is a gas to be detected by the gas detector D, and the measurement target gas is a gas in the environment to be measured that may include the detection target gas. That is.

In the present embodiment, the gas detector D includes a gas flow path F that is fluidly connected to the electrochemical gas sensor 1 and supplies the measurement target gas to the electrochemical gas sensor 1, as shown in FIG. The gas flow path F extends between the gas inflow port F1 into which the measurement target gas flows in and the gas discharge port F2 in which the measurement target gas flows out, and the measurement target gas flowing in from the gas inflow port F1 reaches the gas discharge port F2. It is configured to flow toward. The gas flow path F includes an upstream gas flow path F3 arranged upstream of the electrochemical gas sensor 1, a downstream gas flow path F4 arranged downstream of the electrochemical gas sensor 1, and an upstream gas flow path F3 and downstream. It is arranged between the side gas flow path F4 and includes an intermediate gas flow path F5 which is fluidly connected to the electrochemical gas sensor 1. In the present embodiment, the upstream gas flow path F3 is the internal space of the gas suction pipe P1, the downstream gas flow path F4 is the internal space of the gas discharge pipe P2, and the intermediate gas flow path F5 is the gas flow path F. Is embodied as a space formed between the flow path connecting member P3 that fluidly connects to the electrochemical gas sensor 1 and the electrochemical gas sensor 1 (see FIG. 2). Although the gas detector D is provided with the gas flow path F in the present embodiment, the gas detector D may be installed in the measurement environment without providing the gas flow path F.

In the present embodiment, the gas detector D includes a gas suction device P that sucks the gas to be measured, as shown in FIG. The gas suction device P sucks the gas to be measured and supplies the gas to be measured to the electrochemical gas sensor 1. By providing the gas suction device P, the gas detector D can guide the gas to be measured in an environment away from the place where the electrochemical gas sensor 1 is arranged to the electrochemical gas sensor 1, and the gas suction device P can be used. Compared with the case where the gas sensor 1 is not provided, the gas to be measured can be supplied to the electrochemical gas sensor 1 at a high speed, and the detection time of the gas to be detected can be shortened.

In the present embodiment, the gas suction device P is provided in the gas flow path F as shown in FIG. 1, and is configured so that the gas to be measured can flow through the gas flow path F (for example, at a predetermined flow velocity). Will be done. More specifically, the gas suction device P is provided in the downstream gas flow path F4 by being connected to the gas discharge pipe P2 (see FIG. 2), and the upstream gas on the upstream side of the gas suction device P. The gas to be measured is sucked from the gas inflow port F1 through the flow path F3, the intermediate gas flow path F5, and the downstream gas flow path F4, and through the downstream gas flow path F4 on the downstream side of the gas suction device P. The gas to be measured is discharged from the gas discharge port F2. Although the gas detector D is provided with the gas suction device P in the present embodiment, the gas detector D is installed in the measurement environment without the gas suction device P, and the gas to be measured is generated by natural convection in the measurement environment. It may be configured to be guided by the electrochemical gas sensor 1.

The gas detector D may have a configuration included in a known gas detector in addition to the configuration described above. For example, the gas detector D may include an arithmetic unit (not shown) and may be configured to determine the presence / absence and / or amount of the gas to be detected based on the detection signal of the electrochemical gas sensor 1. Further, the gas detector D may be provided with a notification device (not shown) so as to notify the user that the detection target gas has been detected. The notification device may be a visual type, an auditory type, a tactile type, or the like, and may be configured to notify the user of information regarding the detection result.

<Electrochemical gas sensor>
The electrochemical gas sensor 1 detects the detection target gas by utilizing the electrochemical reaction caused by the detection target gas. The electrochemical gas sensor 1 is not particularly limited as long as it can detect the gas to be detected by using an electrochemical reaction, but it may be a constant potential electrolytic gas sensor as described in detail below, for example. can. Examples of the detection target gas to be detected by the electrochemical gas sensor 1 in the present embodiment include a special high-pressure gas containing monosilane, disilane, arsine, phosphine, diborane, monogerman, or hydrogen selenide. However, the electrochemical gas sensor 1 is not limited to the special high-pressure gas, and sulfur dioxide, hydrogen sulfide, nitrogen dioxide, nitrogen monoxide, phosgen, hydrogen cyanide, silicon tetrafluoride, silicon trifluoride, boron trichloride, Boron tribromide, bromine, phosphorus oxychloride, alcine, diborane, carbon monoxide, ammonia, chlorine, fluorine, German, hydrogen fluoride, hydrogen selenium, dichlorosilane, hydrogen bromide, hydrogen chloride, phosphine, tungsten hexafluoride , Hydrogen tetrachloride, silane, chlorine trifluoride, disilane, sulfur tetrafluoride, phosphorus trifluorine, phosphorus pentafluoride, nitrogen trifluoride, and other gases other than special high-pressure gas can also be detected. As described above, the measurement target gas is an environmental atmosphere gas in an environment in which the detection target gas may be contained, and examples thereof include an atmospheric atmosphere gas.

In the present embodiment, the electrochemical gas sensor 1 is fluidly connected to the gas flow path F and detects the detection target gas contained in the measurement target gas flowing through the gas flow path F, as shown in FIG. The electrochemical gas sensor 1 is fluidly connected to the gas flow path F so that the measurement target gas flows into the electrochemical gas sensor 1 at a flow velocity smaller than the flow velocity of the measurement target gas flowing in the gas flow path F, for example. As shown in FIG. 2, the electrochemical gas sensor 1 is connected to the flow path connecting member P3 connected to the gas suction pipe P1 and the gas discharge pipe P2, but for the above purpose, the inside of the flow path connecting member P3. The gas to be measured flowing through the intermediate gas flow path F5 flows into the inside of the electrochemical gas sensor 1 from the direction intersecting with the intermediate gas flow path F5 formed in (the direction orthogonal to the intermediate gas flow path F5 in the illustrated example). It is connected to the flow path connecting member P3. In this way, by making the velocity of the measurement target gas flowing into the electrochemical gas sensor 1 smaller than the velocity of the measurement target gas in the gas flow path F, the measurement target gas is quickly guided to the vicinity of the electrochemical gas sensor 1. However, it is possible to suppress the disturbance caused by the gas to be measured in the electrochemical gas sensor 1 and stabilize the detection signal of the electrochemical gas sensor 1. However, the electrochemical gas sensor 1 may be installed in a measurement environment containing the gas to be measured without being fluidly connected to the gas flow path F. Further, the gas to be measured may flow into the electrochemical gas sensor 1, and may not necessarily flow into the electrochemical gas sensor 1 at a flow velocity smaller than the flow velocity of the gas to be measured flowing in the gas flow path F. The gas may flow into the electrochemical gas sensor 1 at a flow velocity greater than or equal to the flow velocity of the gas to be measured flowing in the flow path F.

The electrochemical gas sensor 1 only needs to be able to detect the detection target gas contained in the measurement target gas, and its configuration is not particularly limited. In the present embodiment, the electrochemical gas sensor 1 houses the electrode 2 for detecting the gas to be detected, the electrolytic solution 3 in contact with the electrode 2, the electrode 2 and the electrolytic solution 3, as shown in FIG. A container 4 is provided.

The electrode 2 is arranged so as to be in contact with the electrolytic solution 3, and is configured to detect the detection target gas in the measurement target gas that has flowed into the electrolytic solution 3. As shown in FIG. 2, the electrode 2 includes a reaction electrode 21 that electrochemically reacts the gas to be detected, a counter electrode 22 with respect to the reaction electrode 21, and a reference electrode 23 that serves as a reference for the potential of the reaction electrode 21. .. The reaction electrode 21, the counter electrode 22, and the reference electrode 23 are arranged in the container 4 so as to be in contact with the electrolytic solution 3, and are connected to, for example, a control means such as a known potentiostat (not shown) via a lead wire.

The reaction electrode 21 is an electrode to which a constant voltage is applied with reference to the potential of the reference electrode 23 to cause an electrochemical reaction in the gas to be detected. As shown in FIG. 2, the reaction electrode 21 is formed on the diaphragm 5, which will be described later, so as to come into contact with the electrolytic solution 3. The reaction electrode 21 can be formed, for example, by applying and firing a paste made of a known electrode material on the diaphragm 5. The electrode material constituting the reaction electrode 21 can be appropriately selected depending on the type of gas to be detected, the electrolytic solution to be used, and the like, such as a carbon catalyst.

The counter electrode 22 is an electrode that causes another electrochemical reaction in response to the electrochemical reaction of the gas to be detected at the reaction electrode 21. As shown in FIG. 2, the counter electrode 22 is formed on the diaphragm 6 described later so as to be in contact with the electrolytic solution 3, and is arranged so as to face the reaction electrode 21 via the electrolytic solution 3. The counter electrode 22 can be formed, for example, by applying and firing a paste made of a known electrode material on the diaphragm 6. The electrode material constituting the counter electrode 22 can be appropriately selected depending on the type of gas to be detected, the electrolytic solution to be used, and the like, such as a carbon catalyst.

The reference electrode 23 is an electrode that serves as a reference for the potential of the reaction electrode 21. As shown in FIG. 2, the reference electrode 23 is formed on the diaphragm 6 so as to be in contact with the electrolytic solution 3, and is arranged together with the counter electrode 22 so as to face the reaction electrode 21 via the electrolytic solution 3. The reference electrode 23 can be configured as, for example, a silver wire fixed on the diaphragm 6. However, the electrode material constituting the reference electrode 23 is not particularly limited, and can be appropriately selected depending on the type of gas to be detected, the electrolytic solution to be used, and the like.

In the electrochemical gas sensor 1 of the present embodiment, a constant voltage is applied to the reaction electrode 21 with reference to the potential of the reference electrode 23, and a constant potential difference is added to the reaction electrode 23. The reaction electrode 21 to which a constant potential difference is added to the reference electrode 23 causes an electrochemical reaction in the detection target gas that has flowed into the electrolytic solution 3 in contact with the reaction electrode 21. When an electrochemical reaction of the gas to be detected occurs, another corresponding electrochemical reaction occurs on the counter electrode 22 side in response to the electrochemical reaction. As a result of the electrochemical reaction occurring at the reaction electrode 21 and the counter electrode 22, an electrolytic voltage is generated between the reaction electrode 21 and the counter electrode 22, and an electrolytic current flows. By detecting the electrolytic voltage and / or the electrolytic current, the detection target gas can be detected, and the concentration of the detection target gas can be obtained according to the magnitude of the electrolytic voltage and / or the electrolytic current.

The electrolytic solution 3 is a solution having electrical conductivity. The electrolytic solution 3 is housed in the container 4 so as to come into contact with the electrode 2. The electrolytic solution 3 can be appropriately selected according to the type of the detection target gas to be detected, the type of the electrode 2 used for detection, and the like. For example, an acidic aqueous solution such as sulfuric acid or phosphoric acid, or an odor. A neutral salt aqueous solution such as lithium chloride or calcium chloride can be used.

The container 4 is a member that houses the electrode 2 and the electrolytic solution 3. As shown in FIG. 2, the container 4 communicates with the inflow port 41 for the gas to be measured including the detection target gas to flow into the container 4 and the inflow port 41, and accommodates the electrolytic solution 3 to accommodate the electrolytic solution 3. A unit 42 communicates with the electrolytic solution accommodating unit 42, and an outflow port 43 for allowing the gas in the electrolytic solution accommodating unit 42 to flow out of the container 4 is provided. The container 4 is connected to the flow path connecting member P3 so that the extending direction X of the inflow port 41 intersects (orthogonally in the illustrated example) with respect to the gas flow path F (intermediate gas flow path F5). As a result, the gas to be measured flows into the container 4 through the inflow port 41 at a flow velocity smaller than that in the gas flow path F.

As shown in FIG. 2, the inflow port 41 has an opening of one end 41a connected to the outside of the container 4 and an opening of the other end 41b connected to the electrolyte accommodating portion 42 in the container 4. It is arranged so that the gas to be measured flows from the opening of the end portion 41a on one side toward the opening of the end portion 41b on the other side. A part of the inflow port 41 is composed of a lumen formed inside the inflow side lid member 44 for fixing the diaphragm 5 described later to the container 4.

As shown in FIG. 2, the outlet 43 has an opening of one end 43a connected to the electrolyte accommodating portion 42 in the container 4 and an opening of the other end 43b connected to the outside of the container 4. It is arranged so that the gas flows from the opening of the end portion 43a on one side toward the opening of the end portion 43b on the other side. A part of the outflow port 43 is composed of a lumen formed inside the outflow side lid member 46 for fixing the diaphragm 6 described later to the container 4.

As shown in FIG. 2, the electrolytic solution accommodating portion 42 is connected to the opening of the end portion 41b on the other side of the inflow port 41, and the gas to be measured outside the container 4 flows into the inside through the inflow port 41. , The gas in the electrolytic solution accommodating portion 42 is configured to flow out of the container 4 by being connected to the opening of the end portion 43a on one side of the outflow port 43. A diaphragm 5 is provided on the inner side (the other end 41b side) of the container 4 at the inflow port 41 to prevent the electrolytic solution 3 from flowing out of the container 4 from the inflow port 41. Further, on the inner side (one end 43a side) of the container 4 at the outlet 43, a diaphragm 6 is provided to prevent the electrolytic solution 3 from flowing out of the container 4 from the outlet 43. The diaphragms 5 and 6 prevent the electrolytic solution 3 in the electrolytic solution accommodating portion 42 from flowing out to the outside of the container 4 through the inflow port 41 / outflow port 43, respectively, while the gas to be measured is outside the container 4. Allows the gas to flow into the electrolytic solution accommodating portion 42 / the gas in the electrolytic solution accommodating portion 42 to flow out to the outside of the container 4. Therefore, the electrolytic solution accommodating portion 42 can accommodate the electrolytic solution 3 inside by closing the inlet 41 and the outflow port 43 connected to the electrolytic solution accommodating portion 42 in a liquid-tight manner by the diaphragms 5 and 6. By allowing the passage of the gas through the diaphragms 5 and 6, the gas can flow into the inside and the gas can flow out from the inside.

As shown in FIG. 2, the diaphragm 5 is laminated with reaction poles 21, the reaction poles 21 face the electrolyte accommodating portion 42 side, and the diaphragm 5 faces one end 41a side of the inflow port 41. As such, it is fixed by the inflow side lid member 44 via a known sealing means such as an O-ring 45. Further, in the diaphragm 6, the counter electrode 22 and the reference pole 23 are laminated, the counter electrode 22 and the reference pole 23 face the electrolyte accommodating portion 42 side, and the diaphragm 6 faces the other end portion 43b side of the outlet 43. As such, it is fixed by the outflow side lid member 46 via a known sealing means such as an O-ring 47.

The diaphragms 5 and 6 are not particularly limited as long as they can prevent the passage of the electrolytic solution 3 and allow the passage of gas. As the diaphragms 5 and 6, for example, a porous polytetrafluoroethylene film having water repellency and gas permeability can be used. The diaphragms 5 and 6 can be omitted as appropriate depending on the arrangement of the inflow port 41 and the outflow port 43 with respect to the electrolytic solution accommodating portion 42. In that case, the reaction electrode 21, the counter electrode 22, and the reference electrode 23 are independently housed in the container 4 without being provided on the diaphragms 5 and 6.

The container 4 may have enough strength to accommodate and hold the electrode 2 and the electrolytic solution 3, and is formed by using a known resin material such as polycarbonate, vinyl chloride, polyethylene, polypropylene, or polytetrafluoroethylene. be able to.

As shown in FIG. 2, the electrochemical gas sensor 1 includes an ozone gas removing means 7 provided at the inflow port 41. The ozone gas removing means 7 allows the passage of the detection target gas and removes the ozone gas contained in the measurement target gas. The ozone gas removing means 7 is provided at the inflow port 41, and by removing the ozone gas contained in the gas to be measured, the inflow of the ozone gas into the electrolytic solution 3 housed in the electrolytic solution accommodating unit 42 can be suppressed. can. Therefore, the electrochemical gas sensor 1 can suppress the interference caused by the ozone gas and enhance the selectivity of the detection target gas.

The ozone gas removing means 7 is provided in the inflow port 41 if it allows the passage of at least a part of the detection target gas and can remove at least a part of the ozone gas contained in the measurement target gas. The position to be used is not particularly limited. As shown in FIG. 2, for example, the ozone gas removing means 7 may be provided on the outer side of the container 4 at the inflow port 41 from the diaphragm 5, that is, on the upstream side of the diaphragm 5 at the inflow port 41. By providing the ozone gas removing means 7 on the upstream side of the diaphragm 5, it is possible to remove the ozone gas contained in the measurement target gas before the measurement target gas flowing into the inflow port 41 reaches the diaphragm 5, thereby electrolyzing. The inflow of ozone gas into the electrolytic solution 3 housed in the liquid accommodating portion 42 can be more reliably suppressed.

The ozone gas removing means 7 allows at least a part of the detection target gas to pass so that the passage rate of the detection target gas is larger than the passage rate of the detection target gas, and at least one of the ozone gases contained in the measurement target gas. The configuration is not particularly limited as long as the portion can be removed. The ozone gas removing means 7 may be, for example, a filter having a lower adsorption ability of a measurement target gas (particularly a detection target gas) than activated carbon, silica gel or zeolite, and promoting decomposition of ozone gas. Here, since ozone gas has a property of being easily decomposed, it is easily decomposed by colliding with an object such as a filter and reacting. Therefore, by using a filter having a low adsorption capacity of the gas to be measured as the ozone gas removing means 7, it is possible to promote decomposition by collision / reaction of the ozone gas while suppressing the adsorption of gases other than the ozone gas (particularly the gas to be detected). Can be done.

The ozone gas removing means 7 preferably does not contain activated carbon, silica gel or zeolite for the purpose of suppressing the adsorption capacity of the gas to be measured to be lower. Since the ozone gas removing means 7 does not contain activated carbon and silica gel, the adsorption of the gas to be measured can be further suppressed, and the adsorption of the gas to be detected can be further suppressed, so that the detection sensitivity of the gas to be detected is further reduced. While suppressing it, the interference of ozone gas can be further suppressed. Therefore, as the ozone gas removing means 7, it is preferable that only the ozone gas removing means 7 which does not contain activated carbon, silica gel or zeolite and has a low adsorption ability of the gas to be measured is provided at the inflow port 41.

The ozone gas removing means 7 may include, for example, a fluororesin filter 71 and / or a metal filter 72, as shown in FIG. Both the fluororesin filter 71 and the metal filter 72 have a lower adsorption ability of the measurement target gas (particularly the detection target gas) than the activated carbon, silica gel or zeolite, and can promote the decomposition of ozone gas. The ozone gas removing means 7 may include either the fluororesin filter 71 or the metal filter 72, but may include both the fluororesin filter 71 and the metal filter 72. When the ozone gas removing means 7 includes both the fluororesin filter 71 and the metal filter 72, for example, as shown in FIG. 2, the fluororesin filter 71 and the metal filter 72 are on the upstream side of the inflow port 41. It is preferable that they are arranged in order from the to the downstream side. By providing the fluororesin filter 71 on the upstream side and the metal filter 72 on the downstream side, ozone gas contained in the measurement target gas can be removed more efficiently. It is considered that this is because the gas diffusion function of the fluororesin filter 71 and the ozone gas reaction decomposition function of the metal filter 72 function in a well-balanced manner. That is, since the fluororesin filter 71 is arranged on the upstream side, the fluororesin filter 71 diffuses the measurement target gas, and the measurement target gas flows toward the metal filter 72 in a random direction. It is considered that the probability that the ozone gas contained in the measurement target gas collides with the metal filter 72 increases, and more ozone gas can be decomposed and removed.

The fluororesin filter 71 is a porous member formed of fluororesin through which gas can pass. Since the fluororesin filter 71 is made of fluororesin, the adsorption of the gas to be measured (particularly the gas to be detected) is suppressed. Therefore, the fluororesin filter 71 can promote decomposition due to collision of ozone gas while suppressing adsorption of the measurement target gas (particularly the detection target gas). The fluororesin filter 71 may have a plurality of through holes through which gas can pass, and for example, a fibrous porous film can be used. The fluororesin used in the fluororesin filter 71 may be any as long as it suppresses the adsorption of the gas to be measured, and is not particularly limited, but for example, polytetrafluoroethylene (PTFE) or perfluoroalkoxy alkane. Alkane (PFA), perfluoroethylene propene copolymer (FEP) and the like can be used.

The metal filter 72 is a porous member formed of metal through which gas can pass. The metal filter 72 is formed of metal to promote a decomposition reaction of colliding ozone gas. The metal filter 72 may have a plurality of through holes through which gas can pass, and for example, a metal mesh or punching metal can be used. The metal constituting the metal filter 72 is not particularly limited as long as it can suppress the adsorption of the gas to be measured and can promote the decomposition reaction of ozone gas. For example, stainless steel, aluminum, copper and the like can be used, and stainless steel having a dense oxide film on the surface of which adsorption of gas is more suppressed can be preferably used.

The metal filter 72 can be set to a thickness that can secure an appropriate contact time with the measurement target gas in order to suppress the decomposition reaction of the detection target gas while maintaining the ozone gas reaction decomposition ability. For example, from the viewpoint of suppressing the decomposition reaction of the detection target gas, the metal filter 72 is preferably formed thin so that the contact time with the measurement target gas, particularly the detection target gas, is as short as possible. In that case, in order to improve the decomposition efficiency of ozone gas in a short contact time, as described above, a fluororesin filter 71 having a relatively small decomposition ability of ozone gas or a gas to be detected is provided on the upstream side of the metal filter 72. Therefore, the measurement target gas, particularly the ozone gas, may be diffused (dispersed) to increase the contact probability with the ozone gas. Further, in order to secure an appropriate contact time between the metal filter 72 and the gas to be measured, a fluororesin filter 71 is provided on the upstream side to control the diffusion rate of the gas to be measured and the contact time. Can also be adjusted.

As the ozone gas removing means, in addition to the fluororesin filter and the metal filter, a glass fiber filter having a low gas adsorption capacity may be used as a filter for promoting the decomposition of the ozone gas because the adsorption capacity of the gas to be measured is low. can. Further, the ozone gas removing means is not limited to the present embodiment as long as the ozone gas can be removed while suppressing the decrease in the detection signal intensity of the detection target gas, and other known ozone gas removing means such as ultraviolet irradiation. Can also be used.

As shown in FIG. 2, the electrochemical gas sensor 1 is provided on the upstream side (one end 41a side) of the inflow port 41, and is provided with a deceleration means 8 for reducing the inflow speed of the gas to be measured into the container 4. You may have it. In this case, the deceleration means 8 is provided on the upstream side of the inflow port 41, and the ozone gas removing means 7 is provided on the downstream side of the inflow port 41. As will be described in detail below, the electrochemical gas sensor 1 is provided with the deceleration means 8 on the upstream side of the inflow port 41 and the ozone gas removing means 7 on the downstream side of the inflow port 41 to further reduce the ozone gas in the gas to be measured. It can be removed efficiently. Although the electrochemical gas sensor 1 shown in FIG. 2 shows an example in which the ozone gas removing means is provided, the ozone gas removing means is provided as in the modified electrochemical gas sensor 1 shown in FIG. 3, for example. It does not have to be. However, from the viewpoint of adjusting the amount of ozone removed, it is preferable that means capable of removing ozone gas are provided at a plurality of locations, and therefore it is preferable that the electrochemical gas sensor 1 is provided with means for removing ozone gas.

As described above, the speed reduction means 8 is configured to reduce the inflow speed of the gas to be measured into the container 4. For example, when the gas detector D includes the gas suction device P, the gas to be measured is supplied to the inflow port 41 at a predetermined flow velocity by the gas suction device P. The deceleration means 8 diffuses (or scatters, disperses, etc.) the gas molecules of the gas to be measured supplied from the outside of the container 4 into the inflow port 41 in the inflow port 41, thereby causing the gas molecules to flow in the traveling direction. The velocity component in the direction X from one end 41a of the inflow port 41 toward the other end 41b is reduced by changing from the direction X from one end 41a of the inlet 41 toward the other end 41b. In this way, the deceleration means 8 reduces the inflow speed of the measurement target gas supplied from the outside of the container 4 into the inflow port 41 into the container 4, so that the measurement target gas is on the downstream side of the deceleration means 8. It takes a long time to pass through the ozone gas removing means 7 arranged in the above, and the ozone gas in the gas to be measured can be efficiently removed. Further, the deceleration means 8 changes the traveling direction of the gas molecules of the gas to be measured from the direction X from one end 41a of the inflow port 41 toward the other end 41b, so that the gas molecules are removed from the ozone gas removal means 7. The probability of collision with the gas increases, and the ozone gas in the gas to be measured can be efficiently removed.

As the speed reducing means 8, for example, a porous filter can be used. As the porous filter, for example, a porous film formed of a fluororesin such as polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), and perfluoroethylene propene copolymer (FEP) can be used. However, the deceleration means 8 is not particularly limited as long as the inflow speed of the gas to be measured into the container 4 can be reduced, and may be configured by, for example, a pinhole. Further, when the inflow speed of the gas to be measured into the inflow port 41 is not high, for example, when the gas suction device P is not used, the electrochemical gas sensor 1 of the modified example shown in FIG. 3 may be used. The deceleration means 8 may be omitted.

<Ozone gas removal filter>
Next, the details of the ozone gas removal filter O will be described with reference to FIGS. 1, 3 and 4. As shown in FIG. 1, the ozone gas removal filter O is provided upstream of the electrochemical gas sensor 1 and removes at least a part of the ozone gas contained in the measurement target gas before the measurement target gas flows into the electrochemical gas sensor 1. Remove. In the present embodiment, the ozone gas removal filter O is provided in the gas flow path F (upstream side gas flow path F3) upstream of the electrochemical gas sensor 1 and forms a part of the gas flow path F. By providing the ozone gas removal filter O in the gas flow path F, it is possible to efficiently remove the ozone gas in the measurement target gas supplied to the electrochemical gas sensor 1. In particular, the ozone gas removal filter O is configured so that it can be provided in the gas suction pipe P1 (see FIG. 2) forming the upstream gas flow path F3 as in the present embodiment, so that the gas detection already installed can be performed. It can be easily incorporated into the vessel without requiring major modifications. However, if the ozone gas removal filter O is provided upstream of the electrochemical gas sensor 1, the position where it is arranged is not particularly limited, and the ozone gas removal filter O is provided at a place other than the gas flow path F where the gas to be measured is flowing. For example, the gas sensor unit may be provided integrally with the electrochemical gas sensor 1 and may form a gas sensor unit together with the electrochemical gas sensor 1.

The ozone gas removal filter O is configured to remove at least a part of the ozone gas contained in the measurement target gas and suppress the adsorption of the detection target gas contained in the measurement target gas when the measurement target gas passes through. .. For that purpose, the ozone gas removal filter O includes a filter member O1 whose surface contains a material having a lower gas adsorption property than activated carbon, silica gel or zeolite, as shown in FIG. The filter member O1 is arranged in the ozone gas removal filter O so that the measurement target gas collides with the surface of the filter member O1. Since the ozone molecules constituting ozone gas have a property of being easily decomposed, they are easily decomposed by colliding with and reacting with the filter member O1 regardless of the type of material constituting the surface of the filter member O1. .. On the other hand, by including a material having low gas adsorption property on the surface of the filter member O1, the adsorption of gas (particularly the gas to be detected) to the filter member O1 is suppressed. Therefore, the ozone gas removal filter O promotes decomposition by collision / reaction of ozone molecules while suppressing adsorption of gas (particularly the gas to be detected) by using the filter member O1 whose surface contains a material having low gas adsorption property. can do. By preferentially removing the ozone gas by the ozone gas removing filter O, the gas detector D can suppress the interference by the ozone gas and enhance the selectivity of the detection target gas.

The filter member O1 preferably contains a material having a lower gas adsorption property than activated carbon, silica gel, or zeolite, on the entire surface thereof, for the purpose of further suppressing the adsorption of gas (particularly the gas to be detected). By including a material having a lower gas adsorption property than activated carbon, silica gel or zeolite on the entire surface of the filter member O1, the probability that a gas (particularly the gas to be detected) is adsorbed can be further reduced. Further, the filter member O1 preferably does not contain activated carbon, silica gel or zeolite on its surface for the purpose of further suppressing the adsorption of gas (particularly the gas to be detected). However, at least a part of the surface of the filter member O1 may contain a material having a lower gas adsorption property than activated carbon, silica gel or zeolite, and a part of the surface thereof may contain another material. No. Further, the filter member O1 may contain a material having a lower gas adsorption property than activated carbon, silica gel or zeolite as a whole, or the inside thereof is formed of another material, and the activated carbon, only on the surface. It may contain a material having a lower gas adsorption property than silica gel or zeolite.

The material contained in the surface of the filter member O1 may be at least a material having a lower adsorption property of the detection target gas than activated carbon, silica gel or zeolite, and is not particularly limited, but further suppresses the adsorption of the detection target gas. However, from the viewpoint of further enhancing the selectivity of the gas to be detected, the fluororesin is preferable. The fluororesin is not particularly limited, and for example, polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), perfluoroethylene propene copolymer (FEP) and the like can be used.

In the present embodiment, the filter member O1 is formed in a substantially cylindrical shape (for example, a substantially cylindrical shape) extending in the axis Z direction, as shown in FIGS. 3 and 4. Since the filter member O1 is formed in a substantially tubular shape, the surface on which the gas to be measured may collide becomes both the outer surface and the inner surface of the cylinder, so that the probability that the gas to be measured collides with the filter member O1 is high. Become. As a result, more ozone gas can be removed, and interference of ozone gas can be suppressed to a lower level. However, the filter member O1 may contain at least a material having a lower gas adsorption property than activated carbon, silica gel or zeolite on the surface, and is not limited to the substantially tubular member as in the present embodiment. A member having another shape such as an actual pellet may be used. The size and amount of the filter member O1 are not particularly limited, but for example, from the viewpoint of suppressing a decrease in the passing amount of the detection target gas, the volume in the filter member accommodating portion O2, which will be described later, is approximately half or less. The size and amount of filling can be selected according to the filling rate of.

As shown in FIG. 4, the ozone gas removal filter O further removes the ozone gas from the measurement target gas and further suppresses the interference caused by the ozone gas. As shown in FIG. 4, the measurement target gas collides with the surface of the filter member O1 and scatters. As described above, it is preferable that the gas flow path F of the gas to be measured is formed. Here, scattering means that the flow direction of the gas to be measured changes due to the collision. That is, in this case, the ozone gas removal filter O is configured so that the gas to be measured collides with the surface of the filter member O1 and is scattered in a direction inclined with respect to the original gas flow path F. When the gas to be measured collides with the filter member O1 and scatters, the probability of colliding with another filter member O1 or another member increases, and the decomposition of ozone gas, that is, ozone molecules is further promoted. From such a viewpoint, it is preferable that the ozone gas removal filter O forms the gas flow path F of the gas to be measured so that the gas to be measured collides with the surface of the filter member O1 a plurality of times and is scattered.

In the present embodiment, the ozone gas removal filter O includes a filter member accommodating portion O2 including an inlet O221 and an outlet O231, as shown in FIGS. 3 and 4. The filter member accommodating portion O2 is arranged along the gas flow path F so that the inlet O221 and the outlet O231 are positioned on the gas flow path F (upstream gas flow path F3). The filter member O1 is housed in the filter member accommodating portion O2 so that the surface of the filter member O1 is inclined with respect to the axis Y of the filter member accommodating portion O2 connecting the inlet O221 and the outlet O231. Since the surface of the filter member O1 is inclined with respect to the axis Y, the gas to be measured flowing along the axis Y of the filter member accommodating portion O2 collides with the surface of the filter member O1 and is scattered. It scatters in a direction inclined with respect to the axis Y of the member accommodating portion O2. As a result, the gas to be measured has a high probability of colliding with another filter member O1 or another member (for example, the inner wall of the filter member accommodating portion O2) after being scattered from the surface of the filter member O1, thereby increasing the probability of the filter member colliding with the filter member O1. The proportion of ozone gas (ozone molecules) that collides with O1 and the like increases, and the decomposition of ozone gas (ozone molecules) is further promoted. From such a viewpoint, it is preferable that a plurality of filter members O1 whose surfaces are inclined with respect to the axis Y of the filter member accommodating portion O2 are accommodated in the filter member accommodating portion O2.

In the present embodiment, in the filter member O1 formed in a substantially tubular shape, as shown in FIGS. 3 and 4, the axis Z of the filter member O1 is inclined with respect to the axis Y of the filter member accommodating portion O2. It is arranged in the gas flow path F. The surface of the filter member O1 so arranged is inclined with respect to the axis Y of the filter member accommodating portion O2. As a result, as described above, the gas to be measured flowing along the axis Y of the filter member accommodating portion O2 is scattered in a direction inclined with respect to the axis Y of the filter member accommodating portion O2, and is separated from another filter member O1. (For example, the inner wall of the filter member accommodating portion O2) has a higher probability of colliding with the member of the filter member (for example, the inner wall of the filter member accommodating portion O2). Be promoted. From such a viewpoint, it is preferable that the ozone gas removal filter O includes a plurality of filter members O1 arranged so that the axes Z face different directions as shown in the drawing. That is, it is preferable that the ozone gas removal filter O includes a plurality of filter members O1 whose axes Z are oriented in random directions with respect to the direction in which the gas to be measured flows. As a result, the gas to be measured is scattered in various directions, and the probability of colliding with another filter member O1 or another member (for example, the inner wall of the filter member accommodating portion O2) is further increased.

In the present embodiment, the filter member accommodating portion O2 is provided with an inlet O221 and an outlet O231 at both ends as shown in FIGS. 3 and 4, and a gas flow path F is provided along an axis Y connecting the inlet O221 and the outlet O231. Is formed in a substantially cylindrical shape (for example, a substantially cylindrical shape) so that is formed inside. The filter member accommodating portion O2 internally accommodates one or more filter members O1 so that the filter member O1 is arranged along the axis Y connecting the inlet O221 and the outlet O231. As shown in the figure, the filter member accommodating portion O2 has an accommodating portion main body member O21 formed in a substantially cylindrical shape (for example, a substantially cylindrical shape) so as to extend along the axis Y, and the accommodating portion main body member O21 in the axis Y direction. An inlet side lid member O22 attached to one end (inlet O221 side) and an outlet side lid member O23 attached to the other end (outlet O231 side) of the accommodating portion main body member O21 in the axial Y direction. It has. The inlet side lid member O22 and the outlet side lid member O23 are provided with an inlet O221 and an outlet O231, respectively, and are fitted into both ends of the accommodating portion main body member O21 to partially close the ends of the accommodating portion main body member O21. .. However, the filter member accommodating portion O2 may accommodate one or a plurality of filter members O1, and its shape is not limited to the illustrated example.

The filter member accommodating portion O2 may accommodate one or more filter members O1, and the material thereof is not particularly limited. For example, a gas (particularly a detection target gas) rather than activated carbon, silica gel, or zeolite is used. ) May contain a material with low adsorptivity on the surface of the inner wall. By containing a material having a lower gas adsorption property than activated carbon, silica gel or zeolite on the surface of the inner wall of the filter member accommodating portion O2, the gas to be measured collides with and scatters with the filter member O1 and is attached to the inner wall of the filter member accommodating portion O2. Even if a collision occurs, the decomposition of ozone gas can be promoted while suppressing the adsorption of the gas to be detected on the inner wall. Examples of the material contained in the surface of the inner wall of the filter member accommodating portion O2 include fluororesin, and examples of the fluororesin include polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), and perfluoroethylene propene copolymer (perfluoroethylene propene copolymer). FEP) and the like are exemplified.

As shown in FIGS. 3 and 4, the filter member accommodating portion O2 may include water-repellent and gas-permeable sheets O24, O25 for closing the inlet O221 and / or the outlet O231. The sheets O24 and O25 are configured to prevent the passage of liquid and allow the passage of gas. By closing the inlet O221 and the outlet O231 of the filter member accommodating portion O2 with the sheets O24 and O25, it is suppressed that the filter member O1 goes out from the inlet O221 and the outlet O231 of the filter member accommodating portion O2. Further, by providing the sheet O24 at least upstream of the filter member O1 (on the inlet O221 side of the filter member accommodating portion O2), the liquid enters the inside of the filter member accommodating portion O2 together with the gas to be measured, and the filter member O1 is moved. Exposure to liquid can be suppressed, and deterioration of the performance of the filter member O1 can be suppressed. Further, since the gas detector D is provided with either of the sheets O24 and O25 upstream of the electrochemical gas sensor 1, the liquid contained in the measurement environment is suppressed from entering the inside of the electrochemical gas sensor 1. Deterioration of the performance of the electrochemical gas sensor 1 can be suppressed.

The sheets O24 and O25 may be configured to suppress the passage of the liquid and allow the passage of the gas, and are not particularly limited, but for example, water repellency and gas permeability. A porous polytetrafluoroethylene film having can be used.

As shown in FIG. 3, the ozone gas removal filter O may include an accommodating container O3 for accommodating the filter member accommodating portion O2. The storage container O3 is arranged on the gas flow path F (upstream gas flow path F3) in a state of accommodating the filter member accommodating portion O2, so that the accommodating filter member accommodating portion O2 is positioned on the gas flow path F. .. As shown in the drawing, the storage container O3 has a storage container main body O31 formed in a substantially cylindrical shape (for example, a substantially cylindrical shape) so as to extend along the gas flow path F, and an upstream end portion of the storage container main body O31. The upstream side flow path connecting member O32 attached to the container main body O31 and the downstream side flow path connecting member O33 attached to the downstream end of the storage container main body O31 are provided. The upstream side flow path connecting member O32 and the downstream side flow path connecting member O33 each include an upstream side internal flow path O321 and a downstream side internal flow path O331 through which the gas to be measured passes, and each of them has an internal flow path O321. , O331 is connected to the gas suction pipe P1 (see FIG. 2) constituting the upstream gas flow path F3 so as to communicate with the upstream gas flow path F3.

The upstream side flow path connecting member O32 and the downstream side flow path connecting member O33 are respectively configured to be screwed and connected to the end portion of the storage container main body O31. The upstream side flow path connecting member O32 and the downstream side flow path connecting member O33 are screwed into the respective ends of the storage container main body O31 so as to approach each other and sandwich the filter member housing part O2 from both ends thereof. It is configured. The filter member accommodating portion O2 is sandwiched so that the upstream side flow path connecting member O32 and the downstream side flow path connecting member O33 are in close contact with the end portion of the filter member accommodating portion O2 on the inlet O221 side and the end portion on the outlet O231 side. As a result, the filter member accommodating portion O2 can be arranged more accurately on the gas flow path F, and the upstream side flow path connecting member O32, the downstream side flow path connecting member O33, and the filter member accommodating portion O2, respectively. The measurement target gas is suppressed from leaking from the end portion of the filter member housing portion O2, and the measurement target gas can be more reliably guided into the filter member accommodating portion O2.

Hereinafter, the excellent effects of the gas detector and the ozone gas removal filter of the present embodiment will be described based on the examples. However, the gas detector and the ozone gas removal filter of the present invention are not limited to the following examples.

(Measurement of gas to be measured)
Using the gas detector illustrated in FIG. 1, the measurement target gas of the atmospheric atmosphere gas containing the detection target gas diboran gas (160 ppb) and the atmospheric atmosphere gas containing the interference gas ozone gas (300 ppb, 600 ppb), respectively. Was measured. The suction speed of the gas to be measured was 0.5 L / min. Among the gas detectors illustrated in FIG. 1, one provided with an ozone gas removal filter was used as an example, and one without an ozone gas removal filter was used as a comparative example.

(Electrochemical gas sensor)
As the electrochemical gas sensor, the constant potential electrolytic gas sensor illustrated in FIG. 2 was manufactured. A carbon catalyst was used for the reaction electrode and the counter electrode, a silver wire was used for the reference electrode, and an 8 mol / L lithium bromide aqueous solution was used as the electrolytic solution. A polytetrafluoroethylene porous film (porosity: about 75%, thickness: about 0.1 mm) was used for both the inlet side and outlet side diaphragms. As the speed reducing means, a porous film made of polytetrafluoroethylene (porosity: about 75%, thickness: about 0.1 mm) was used. As a means for removing ozone gas, a fluororesin filter composed of two polytetrafluoroethylene porous films (porosity: about 75%, thickness: about 0.1 mm) is placed on the upstream side, and a stainless steel punching metal is used. A metal filter composed of (porosity: 13%, thickness: 0.15 mm) was arranged on the downstream side.

(Ozone gas removal filter)
As the ozone gas removal filter, the ozone gas removal filter illustrated in FIG. 3 was produced. A cylindrical polycarbonate pipe having an inner diameter of 15 mm and a length of 60 mm was used as the main body member of the accommodating portion of the filter member accommodating portion. Polytetrafluoroethylene porous films (porosity: about 75%, thickness: about 0.1 mm) were attached to both ends of the filter member accommodating portion. The number of filter members that can be accommodated is accommodated in the filter member accommodating portion according to the size of the filter member. The types of filter members housed in the filter member housing section are shown in Table 1 below.

(Measurement of diboran gas reading rate reduction rate and ozone gas removal rate)
Using the gas detectors of Examples and Comparative Examples, the rate of decrease in the indicated value of diboran gas and the rate of ozone gas removal for the gas to be measured after passing through the ozone gas removal filter were measured. The indicated value reduction rate of diboran gas and the removal rate of ozone gas were obtained by measuring the sensor output value for 160 ppb of diboran gas in the atmosphere and the sensor output value for 300 ppb and 600 ppb of ozone gas in the atmosphere, respectively, and each gas was obtained from a comparative example. It was obtained by calculating the rate at which the sensor output value obtained from the examples decreased from the sensor output value. The results are shown in Table 1.

With reference to Table 1, in all the examples, although the indicated value of diboran gas was slightly lowered by providing the ozone gas removal filter, the ratio of the removed ozone gas was larger than the ratio. There is. From this result, it can be seen that by using the above-mentioned ozone gas removal filter in the gas detector, it is possible to reduce the sensitivity of the ozone gas while suppressing the decrease in the sensitivity of the diboran gas. Then, it can be seen that the gas detector can suppress the interference by the ozone gas and enhance the selectivity of the detection target gas by using the above-mentioned ozone gas removal filter.

Further, when Examples 1 to 6 using the cylindrical filter member and Examples 7 to 8 using the pellet-shaped filter member are compared, Examples 1 to 6 are more than Examples 7 to 8. However, the absolute value of the diboran gas indicated value reduction rate is small, and the absolute value of the ozone gas removal rate is large. From this result, it can be seen that by using the cylindrical filter member, it is possible to further reduce the sensitivity of ozone gas while further suppressing the decrease in sensitivity of diboran gas. Then, it can be seen that the gas detector can further suppress the interference by the ozone gas and further enhance the selectivity of the detection target gas by using the cylindrical filter member.

Further, focusing on the difference in the size of the filter members in Examples 1 to 6 using the cylindrical filter member, as the size of the filter member becomes smaller (Examples 5 and 6 → Examples 3 and 4). → In Examples 1 and 2), although the absolute value of the diboran gas indicated value decrease rate is slightly larger, the absolute value of the ozone gas removal rate tends to increase at a larger rate of change. From this result, it can be seen that by using a smaller cylindrical filter member, the sensitivity of the ozone gas can be further lowered, the interference caused by the ozone gas can be further suppressed, and the selectivity of the detection target gas can be further improved.

Further, in Examples 1 to 6 using the cylindrical filter member, paying attention to the difference in the material of the filter member, the case where the filter member is formed of PTFE is more important than the case where the filter member is formed of PFA ( Examples 1, 3, 5 → Examples 2, 4, 6), Although the absolute value of the diboran gas indicated value decrease rate has changed slightly, the absolute value of the ozone gas removal rate increases at a larger rate of change. ing. From this result, it can be seen that by using the cylindrical filter member formed of PTFE, the sensitivity of the ozone gas can be further lowered, the interference by the ozone gas can be further suppressed, and the selectivity of the detection target gas can be further improved. ..

1 Electrochemical gas sensor (constant potential electrolytic gas sensor)
2 Electrode 21 Reaction pole 22 Counter electrode 23 Reference pole 3 Electrolyte 4 Container 41 Inflow port 41a One end of the inflow port 41b The other end of the inflow port 42 Electrolytic solution accommodating part 43 Outlet 43a One end of the outflow port 43b The other end of the outlet 44 Inflow side lid member 45 O-ring 46 Outflow side lid member 47 O-ring 5 diaphragm 6 diaphragm 7 Ozone gas removing means 71 Fluororesin filter 72 Metal filter 8 Deceleration means D gas detector F gas Flow path F1 Gas inflow port F2 Gas discharge port F3 Upstream side gas flow path F4 Downstream side gas flow path F5 Intermediate gas flow path O Ozone gas removal filter O1 Filter member O2 Filter member storage part O21 Storage part main body member O22 Inlet side lid member O221 Inlet O23 Outlet side lid member O231 Outlet O24, O25 Sheet O3 Storage container O31 Storage container body O32 Upstream side flow path connection member O321 Upstream side internal flow path O33 Downstream side flow path connection member O331 Downstream side internal flow path P gas suction device P1 Gas suction pipe P2 Gas discharge pipe P3 Flow path connection member X Direction of extension of inflow port Y Axis of filter member accommodating part Z Axis of filter member

Claims (7)

A gas sensor for detecting the detection target gas contained in the measurement target gas, and
A gas detector arranged upstream of the gas sensor and provided with an ozone gas removal filter for removing ozone gas contained in the measurement target gas.
The ozone gas removal filter includes a filter member having a surface containing a material having a lower gas adsorption property than activated carbon, silica gel or zeolite.
Gas detector. The ozone gas removal filter includes a filter member accommodating portion having an inlet and an outlet.
The filter member is housed in the filter member accommodating portion so that the surface of the filter member is inclined with respect to an axis connecting the inlet and the outlet.
The gas detector according to claim 1. The material is a fluororesin.
The gas detector according to claim 1 or 2. The gas sensor is an electrochemical gas sensor.
The detection target gas is a special high-pressure gas containing monosilane, disilane, arsine, phosphine, diborane, monogerman or hydrogen selenide.
The gas detector according to any one of claims 1 to 3. The gas detector comprises a sheet having water repellency and gas permeability.
The gas detector according to any one of claims 1 to 4. The gas detector includes a gas suction device that sucks the gas to be measured.
The gas detector according to any one of claims 1 to 5. It is an ozone gas removal filter that is arranged upstream of the gas sensor for detecting the detection target gas contained in the measurement target gas and for removing the ozone gas contained in the measurement target gas.
The ozone gas removal filter includes a filter member having a surface containing a material having a lower gas adsorption property than activated carbon, silica gel or zeolite.
Ozone gas removal filter.

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