JP6517423B1 - Constant potential electrolysis type gas sensor - Google Patents

Abstract

An object of the present invention is to provide a constant potential electrolysis type gas sensor in which interference by ozone gas is suppressed and selectivity of a detection target gas is enhanced. A constant potential electrolytic gas sensor according to the present invention includes an electrode 2 for detecting a gas to be detected, an electrolytic solution 3 in contact with the electrode 2, and a container 4 for containing the electrode 2 and the electrolytic solution 3. The container 4 is provided with an inlet 41 for the gas to be measured including the gas to be detected to flow into the container 4, and activated carbon as ozone gas removing means 7 in the inlet 41. It is characterized in that only the ozone gas removing means 7 having a low adsorption capacity of the gas to be measured is provided without containing silica gel. [Selected figure] Figure 1

Description

  The present invention relates to a constant potential electrolysis type gas sensor.

  The toxic gas such as diborane gas has an allowable concentration determined by the High Pressure Gas Safety Act, for example, 0.1 ppm of diborane gas. Therefore, in the working environment where toxic gas is used, it is necessary to control the concentration of toxic gas below the allowable concentration. For that purpose, a gas sensor having sensitivity below the permissible concentration of toxic gas is required.

  As a gas sensor for detecting a detection target gas 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 electrolysis type gas sensor detects the detection target gas by using the electrochemical reaction of the detection target gas in the electrolyte solution. The constant-potential electrolytic gas sensor is highly sensitive and can detect a detection target gas at a ppb level concentration.

JP, 2014-98679, A

  However, when trying to detect the detection target gas of ppb level concentration using a constant potential electrolysis type gas sensor, since ozone gas exists in the atmosphere at almost the same level concentration, the intensity of the signal related to the detection target gas However, an ozone gas signal with an intensity that can not be ignored is measured. Therefore, when detecting a low concentration detection target gas, it is necessary to suppress the interference of ozone gas and to improve the selectivity of the detection target gas.

  For example, in a potentiostatic gas sensor, a gas filter including activated carbon may be used to filter out interference gases other than the gas to be detected. However, the gas filter containing activated carbon has high gas adsorption capacity, and adsorbs not only the interference gas but also the detection target gas. Therefore, since the sensitivity to ozone gas is lowered and the sensitivity of the gas to be detected is lowered by using the gas filter containing activated carbon, the constant potential electrolytic gas sensor can not improve the selectivity of the gas to be detected.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a constant potential electrolysis type gas sensor in which interference by ozone gas is suppressed and selectivity of a detection target gas is enhanced.

  The constant potential electrolysis gas sensor according to the present invention is a constant potential electrolysis gas sensor including an electrode for detecting a gas to be detected, an electrolytic solution in contact with the electrode, and a container for containing the electrode and the electrolytic solution. The container is provided with an inlet for allowing the gas to be measured including the gas to be detected to flow into the container, and the inlet does not contain activated carbon and silica gel as ozone gas removal means, and the object to be measured is It is characterized in that only ozone gas removing means with low gas adsorption capacity is provided.

  Further, a diaphragm is provided on the inner side of the container at the inlet so as to prevent the electrolytic solution from flowing out of the container from the inlet, and the ozone gas removing means is disposed at the inlet from the diaphragm. Preferably, it is provided on the outer side of the container.

  Moreover, it is preferable that the said ozone gas removal means contains a metal filter.

  Moreover, it is preferable that the said ozone gas removal means contains the filter made from a fluororesin.

  Further, it is preferable that the ozone gas removing unit includes a metal filter and a filter made of a fluorine resin, and the filter made of a fluorine resin and the filter made of metal are disposed in order from upstream to downstream of the inflow port. .

  ADVANTAGE OF THE INVENTION According to this invention, the interference by ozone gas can be suppressed and the constant potential electrolysis type gas sensor which raised the selectivity of detection object gas can be provided.

It is sectional drawing of the constant potential electrolysis type gas sensor which concerns on one Embodiment of this invention. It is the schematic of a suction-type gas detector provided with the constant potential electrolysis-type gas sensor of FIG.

  Hereinafter, a constant potential electrolysis gas sensor according to an embodiment of the present invention will be described with reference to the attached drawings. However, the embodiment shown below is an example, and the constant potential electrolysis gas sensor of the present invention is not limited to the following examples.

  As shown in FIG. 1, the constant potential electrolysis type gas sensor 1 of the present embodiment accommodates an electrode 2 for detecting a gas to be detected, an electrolytic solution 3 in contact with the electrode 2, an electrode 2 and an electrolytic solution 3 And a container 4. The constant potential electrolytic gas sensor 1 can be suitably used to detect special high pressure gas such as monosilane, disilane, arsine, phosphine, diborane, monogermane, hydrogen selenide, for example, but is not particularly limited. It can also be used to detect other gases such as carbon monoxide, nitrogen monoxide, hydrogen, methane, nitrogen trifluoride and the like.

  For example, as shown in FIG. 2, the constant potential electrolytic gas sensor 1 is incorporated in a suction gas detector D including a gas suction means P such as a suction pump for suctioning a gas to be measured via a gas inlet I. It can be used. The suction type gas detector D including the gas suction means P and the constant potential electrolytic gas sensor 1 measures the gas including the detection target gas in the measurement environment by the gas suction means P via the gas inlet I arranged in the measurement environment The target gas is sucked, the measurement target gas is guided to the inlet 41 of the container 4 described later at a predetermined flow velocity, and the constant potential electrolysis gas sensor 1 detects the detection target gas in the measurement target gas. Since the suction type gas detector D can freely arrange the gas introduction port I, the gas introduction port I is disposed in the measurement environment at a position separated from the constant potential electrolytic type gas sensor 1 and the measurement environment It is possible to detect the gas to be detected. However, the constant potential electrolysis type gas sensor 1 may be incorporated into another gas detector and used without being incorporated into the suction type gas detector D. And even if the constant potential electrolysis type gas sensor 1 is directly disposed in the measurement environment without using the gas suction means P, the gas to be measured is led to the inflow port 41 of the container 4 by natural convection in the measurement environment. Good.

  The electrode 2 is disposed to be in contact with the electrolytic solution 3 and configured to detect a detection target gas in the measurement target gas flowing into the electrolytic solution 3. In the present embodiment, as shown in FIG. 1, the electrode 2 is a reaction electrode 21 for causing an electrochemical reaction of a gas to be detected, a counter electrode 22 for the reaction electrode 21, and a reference electrode 23 serving as a reference of the potential of the reaction electrode 21. And have. The reactive electrode 21, the counter electrode 22 and the reference electrode 23 are disposed in the container 4 so as to be in contact with the electrolytic solution 3 and connected via lead wires to control means such as a known potentiostat not shown.

  The reactive electrode 21 is an electrode that generates a electrochemical reaction in the gas to be detected when a constant voltage is applied with reference to the potential of the reference electrode 23. In the present embodiment, the reactive electrode 21 is formed on the diaphragm 5 described later so as to be in contact with the electrolytic solution 3 as shown in FIG. The reactive electrode 21 can be formed, for example, by applying and baking a paste made of a known electrode material on the diaphragm 5. The electrode material constituting the reaction electrode 21 can be appropriately selected according to, for example, the type of gas to be detected, the electrolyte to be used, etc., such as a carbon catalyst.

  The counter electrode 22 is an electrode that generates another electrochemical reaction in response to the electrochemical reaction of the gas to be detected at the reaction electrode 21. In the present embodiment, as shown in FIG. 1, the counter electrode 22 is formed on the diaphragm 6 described later so as to be in contact with the electrolytic solution 3 and disposed so as to face the reactive electrode 21 via the electrolytic solution 3. Ru. The counter electrode 22 can be formed, for example, by applying and baking a paste made of a known electrode material on the diaphragm 5. The electrode material constituting the counter electrode 22 can be appropriately selected according to, for example, the type of gas to be detected such as a carbon-based catalyst, the electrolyte used, and the like.

  The reference electrode 23 is an electrode serving as a reference of the potential of the reaction electrode 21. In the present embodiment, as shown in FIG. 1, the reference electrode 23 is formed on the diaphragm 6 so as to be in contact with the electrolytic solution 3, and is opposed to the reactive electrode 21 with the counter electrode 22 through the electrolytic solution 3. Will be placed. The reference electrode 23 can be configured, for example, as 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 according to the type of gas to be detected, the electrolyte to be used, and the like.

  In the constant potential electrolysis gas sensor 1 of the present embodiment, a constant voltage is applied to the reaction electrode 21 based on the potential of the reference electrode 23, and a constant potential difference is applied between the reaction electrode 21 and the reference electrode 23. The reactive electrode 21 to which a constant potential difference is added between the reference electrode 23 and the reference electrode 23 causes an electrochemical reaction in the gas to be detected which has flowed into the electrolytic solution 3 in contact with the reactive electrode 21. When the electrochemical reaction of the gas to be detected occurs, another electrochemical reaction also occurs on the counter electrode 22 side corresponding to the electrochemical reaction. As a result of the electrochemical reaction occurring in the reactive electrode 21 and the counter electrode 22, an electrolytic voltage is generated between the reactive electrode 21 and the counter electrode 22, and an electrolytic current flows. By detecting the electrolytic voltage and / or the electrolytic current, The gas to be detected can be detected, and the concentration of the gas to be detected can be determined 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 accommodated in the container 4 so as to be in contact with the electrode 2. The electrolytic solution 3 can be appropriately selected according to the type of gas to be detected, the type of electrode 2 used for detection, etc. For example, an acidic aqueous solution such as sulfuric acid or phosphoric acid, odor, It is possible to use an aqueous solution of neutral salt such as lithium chloride or calcium chloride.

  The container 4 is a member for containing the electrode 2 and the electrolytic solution 3. In the present embodiment, as shown in FIG. 1, the container 4 is in communication with the inlet 41 for the gas to be measured including the gas to be detected to flow into the container 4 and the inlet 41, and the electrolyte 3 is It includes an electrolytic solution storage unit 42 to be stored, and an outlet 43 in communication with the electrolytic solution storage unit 42 for allowing the gas in the electrolytic solution storage unit 42 to flow out of the container 4.

  As shown in FIG. 1, the inflow port 41 has an opening at one end 41 a connected to the outside of the container 4 and an opening at the other end 41 b connected to the electrolyte solution storage unit 42 in the container 4. And the gas to be measured flows from the opening of the one end 41 a to the opening of the other end 41 b. In the present embodiment, a part of the inflow port 41 is configured as 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. 1, the outlet 43 has an opening at one end 43 a connected to the electrolyte storage portion 42 in the container 4 and an opening at the other end 43 b connected to the outside of the container 4. And so that gas flows from the opening of the one end 43a toward the opening of the other end 43b. In the present embodiment, a part of the outflow port 43 is configured as 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. 1, the electrolyte solution storage unit 42 is connected to the opening of the other end 41 b 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 electrolyte solution storage unit 42 is configured to flow out of the container 4 by being connected to the opening of the end 43 a on one side of the outflow port 43. In the present embodiment, on the inner side (the other end 41 b side) of the container 4 in the inflow port 41, the diaphragm 5 is provided to prevent the electrolyte 3 from flowing out of the container 4 from the inflow port 41. . Further, on the inner side (one end 43 a side) of the container 4 in the outlet 43, a diaphragm 6 is provided which prevents the electrolyte 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 storage unit 42 from flowing out of the container 4 through the inlet 41 / outlet 43, while the gas to be measured is outside the container 4 Flows into the electrolyte container 42 and allows the gas in the electrolyte container 42 to flow out of the container 4. Therefore, the electrolytic solution storage unit 42 is capable of containing the electrolytic solution 3 by closing the inlet 41 and the outlet 43 connected to the electrolytic solution storage unit 42 in a liquid tight manner by the diaphragms 5 and 6, By allowing the diaphragms 5 and 6 to pass the gas, the gas can flow into the inside and the gas can flow out from the inside.

  In this embodiment, as shown in FIG. 1, in the diaphragm 5, the reactive electrode 21 is stacked, the reactive electrode 21 faces the electrolyte solution storage unit 42, and the diaphragm 5 is one end of the inflow port 41. It is disposed to face the side 41 a and fixed by the inflow side lid member 44 through a known sealing means such as an O-ring 45. Further, in the diaphragm 6, the counter electrode 22 and the reference electrode 23 are stacked, and the counter electrode 22 and the reference electrode 23 face the electrolyte solution storage portion 42 side, and the diaphragm 6 faces the other end 43b side of the outlet 43 It is arranged and fixed by the outflow side lid member 46 via a known sealing means such as an O-ring 47.

  The diaphragms 5 and 6 may prevent passage of the electrolytic solution 3 and allow passage of gas, and the configuration thereof is not particularly limited. As the diaphragms 5 and 6, for example, a porous polytetrafluoroethylene film having water repellency can be used. The diaphragms 5 and 6 can be omitted appropriately depending on the arrangement of the inflow port 41 and the outflow port 43 with respect to the electrolyte solution storage unit 42. In that case, the reactive electrode 21, the counter electrode 22 and the reference electrode 23 are accommodated independently in the container 4 without being provided in the diaphragms 5 and 6.

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

  As shown in FIG. 1, the constant potential electrolytic gas sensor 1 includes an ozone gas removing unit 7 provided at the inflow port 41. The ozone gas removal means 7 allows passage of the detection target gas and removes ozone gas contained in the measurement target gas. The ozone gas removing means 7 is provided at the inflow port 41, and suppresses the inflow of the ozone gas into the electrolytic solution 3 contained in the electrolytic solution containing portion 42 by removing the ozone gas contained in the gas to be measured. it can. Therefore, the constant potential electrolysis type gas sensor 1 can suppress the interference by ozone gas and can improve the selectivity of detection object gas.

  The ozone gas removing means 7 is provided in the inflow port 41, and allows the passage of at least a part of the detection target gas, and can be provided in the inflow port 41 if at least a part of the ozone gas contained in the measurement target gas can be removed. There is no particular limitation on the position to be moved. For example, as shown in FIG. 1, the ozone gas removing means 7 may be provided on the outer side of the container 4 at the inlet 41 from the diaphragm 5, that is, on the upstream side of the diaphragm 5 at the inlet 41. By providing the ozone gas removing means 7 on the upstream side of the diaphragm 5, the ozone gas contained in the gas to be measured can be removed before the gas to be measured flowing into the inflow port 41 reaches the diaphragm 5, thereby the electrolysis The inflow of ozone gas into the electrolytic solution 3 contained in the liquid containing portion 42 can be more reliably suppressed.

  The ozone gas removing means 7 allows passage of at least a part of the detection target gas so that at least the ratio of passage of the detection target gas is greater than the ratio of passage of the ozone gas, and at least one of the ozone gas contained in the measurement target gas. The configuration is not particularly limited as long as the part can be removed. The ozone gas removing means 7 may be, for example, a filter that has a low adsorption capacity for the gas to be measured (particularly the gas to be detected) and promotes the decomposition of the ozone gas. Here, since the ozone gas has the property of being easily decomposed, it is easily decomposed by colliding with and reacting with an object such as a filter. 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 the decomposition of the ozone gas by collision or reaction while suppressing the adsorption of the gas other than the ozone gas (especially the gas to be detected). Can.

  It is preferable that the ozone gas removal means 7 does not contain activated carbon and silica gel in order to reduce the adsorption capacity of the gas to be measured. The ozone gas removing means 7 can further suppress the adsorption of the gas to be measured and can further suppress the adsorption of the gas to be detected by not containing activated carbon and silica gel, thereby further reducing the detection sensitivity of the gas to be detected. While suppressing, interference of ozone gas can be suppressed. Therefore, it is preferable that only the ozone gas removing means 7 having a low adsorption capacity of the gas to be measured is provided at the inflow port 41 as the ozone gas removing means 7 without containing activated carbon and silica gel.

  The ozone gas removal means 7 may include, for example, a filter made of a fluorocarbon resin 71 and / or a filter made of a metal 72 as shown in FIG. The fluorine resin filter 71 and the metal filter 72 both have low adsorption ability of the gas to be measured, and can promote the decomposition of the ozone gas. The ozone gas removal means 7 may include either the fluororesin filter 71 and 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 filter 71 made of fluorine resin and the filter 72 made of metal, for example, as shown in FIG. 1, the filter 71 made of fluorine resin and the filter 72 made of metal are located upstream of the inlet 41 Are preferably arranged in order from the downstream side to the downstream side. By providing the fluororesin filter 71 on the upstream side and the metal filter 72 on the downstream side, the ozone gas contained in the gas to be measured can be removed more efficiently. It is considered that this is because the gas diffusion function possessed by the filter 71 made of fluororesin and the ozone gas reactive decomposition function possessed by the filter 72 made of metal function in a well-balanced manner. That is, since the fluorocarbon resin filter 71 is disposed upstream, the gas to be measured is diffused by the fluorocarbon resin filter 71, and the gas to be measured flows in a random direction toward the metal filter 72. The probability that the ozone gas contained in the gas to be measured collides with the metal filter 72 is high, and it is considered that more ozone gas can be decomposed and removed.

  The fluorine resin filter 71 is a porous member formed of a fluorine resin, through which gas can pass. The fluorine resin filter 71 is formed of a fluorine resin to suppress adsorption of the gas to be measured. Therefore, the fluorine resin filter 71 can promote decomposition due to collision of ozone gas while suppressing adsorption of the gas to be measured. As the fluororesin filter 71, a plurality of through holes through which gas can pass may be used, and for example, a fibrous porous film can be used. The fluorine resin used for the fluorine resin filter 71 is not particularly limited as long as adsorption of the gas to be measured is suppressed, and examples thereof include polytetrafluoroethylene, perfluoroalkoxyalkane, and peroxy Fluoroethylene propene copolymers and the like can be used.

  The metal filter 72 is a porous member made of metal and through which gas can pass. The metal filter 72 is formed of a metal to promote the decomposition reaction of the 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 a 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 the ozone gas. For example, stainless steel, aluminum, copper or the like can be used, and stainless steel having a dense oxide film formed on the surface to which adsorption of gas is further suppressed can be suitably used.

  The metal filter 72 can be set to a thickness such that an appropriate contact time with the gas to be measured can be secured in order to suppress the decomposition reaction of the gas to be detected 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 increase the decomposition efficiency of the ozone gas in a short contact time, as described above, the filter 71 made of fluorine resin having a relatively small ability to decompose the ozone gas and the gas to be detected is provided upstream of the metal filter 72 Thus, the contact probability with the ozone gas may be increased by diffusing (dispersing) the gas to be measured, in particular the ozone gas. Also, in order to ensure a proper contact time between the metal filter 72 and the gas to be measured, the diffusion speed of the gas to be measured is controlled by providing the filter 71 made of fluorine resin on the upstream side, and the contact time You can also adjust the

  The ozone gas removal means has a low adsorptive power of the gas to be measured, and as a filter promoting decomposition of the ozone gas, it is also possible to use a glass fiber filter with low gas adsorption capacity, etc. it can. Further, the ozone gas removing means is not limited to the present embodiment as long as ozone gas can be removed while suppressing a decrease in the detection signal strength of the detection target gas, and other known ozone gas removing means such as ultraviolet irradiation can be used. Can also be used.

  As shown in FIG. 1, the constant potential electrolysis gas sensor 1 is provided on the upstream side (one end 41 a side) of the inflow port 41, and is a decelerating means for reducing the inflow velocity of the gas to be measured into the container 4. 8 may be provided. In this case, the decelerating 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 described in detail below, the constant potential electrolytic gas sensor 1 is provided with the decelerating 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 make ozone gas in the gas to be measured Can be removed more efficiently.

  As described above, the decelerating means 8 is configured to reduce the inflow rate of the gas to be measured into the container 4. For example, when the constant potential electrolysis gas sensor 1 is incorporated into a suction gas detector D and used, the gas suction means P supplies the gas to be measured to the inflow port 41 at a predetermined flow rate. The decelerating means 8 causes the traveling direction of the gas molecules to flow in the inflow port 41 by diffusing (or scattering, dispersing, etc.) the gas molecules of the measurement target gas supplied into the inflow port 41 from the outside of the container 4. The velocity component in the direction X from one end 41 a of the inflow port 41 to the other end 41 b is reduced by changing from the direction X from the one end 41 a of the inlet 41 to the other end 41 b. As described above, by reducing the inflow rate of the measurement target gas supplied from the outside of the container 4 into the inlet 41 into the container 4 by the decelerating means 8, the ozone gas in which the measurement target gas is disposed downstream The time for passing through the removing means 7 becomes long, and the ozone gas in the gas to be measured can be efficiently removed. In addition, the gas molecules can be removed from the ozone gas removal means 7 by changing the traveling direction of the gas molecules of the gas to be measured from the direction X from one end 41 a of the inflow port 41 to the other end 41 b by the decelerating means 8. And the ozone gas in the gas to be measured can be efficiently removed.

  For example, a porous filter can be used as the decelerating means 8. As the porous filter, for example, a porous film formed of a fluorine resin such as polytetrafluoroethylene, perfluoroalkoxyalkane or perfluoroethylene propene copolymer can be used. However, the speed reduction means 8 is not particularly limited as long as the inflow rate of the gas to be measured into the container 4 can be reduced, and can be configured by, for example, a pinhole or the like. Further, for example, as in the case where the gas suction means P is not used, when the inflow velocity of the gas to be measured into the inflow port 41 is not large, the speed reduction means 8 can be omitted.

  In the following, the excellent effects of the constant potential electrolysis gas sensor of the present embodiment will be described based on examples. However, the constant potential electrolysis gas sensor of the present invention is not limited to the following examples.

Example 1
The constant potential electrolysis type gas sensor shown in FIG. 1 was produced. A carbon catalyst was used as the reaction electrode and the counter electrode, a silver wire was used as the reference electrode, and an 8 mol / L lithium bromide aqueous solution was used as the electrolyte. For both the inlet side and the outlet side, a polytetrafluoroethylene porous film (porosity: about 75%, thickness: about 0.1 mm) was used. The deceleration means used a polytetrafluoroethylene porous film (porosity: about 75%, thickness: about 0.1 mm). As an ozone gas removal means, a stainless steel punching metal is provided on the upstream side with a fluorine resin filter configured by stacking two sheets of a polytetrafluoroethylene porous film (porosity: about 75%, thickness: about 0.1 mm) A metal filter composed of (porosity: 13%, thickness: 0.15 mm) was disposed downstream.

(Example 2)
A constant potential electrolytic gas sensor similar to that of Example 1 was manufactured except for the ozone gas removing means. As the ozone gas removal means, a metal filter is used, using a fluorine resin filter formed by stacking eight sheets of a porous polytetrafluoroethylene film (porosity: about 75%, thickness: about 0.1 mm). It was not.

(Comparative example)
A constant potential electrolytic gas sensor was produced in which the configuration other than the ozone gas removing means was the same as that of Example 1 without providing the ozone gas removing means.

(Passing rate measurement)
The passing rates of diborane gas and ozone gas passing through the ozone gas removal means were measured using the constant potential electrolysis gas sensors of Examples 1 and 2 and Comparative Example. The passing rates of diborane gas and ozone gas were measured by measuring the sensor output for 0.16 ppm of diborane gas in the atmosphere and the sensor output for 0.6 ppm of ozone gas in the atmosphere, and for each gas, the sensor output value obtained from the comparative example It calculated | required by calculating the ratio of the sensor output value obtained from Example 1, 2. The results are shown in Table 1. In addition, the inflow rate to the inflow port of measurement object gas was 0.5 L / min.

  Looking at Example 1 in Table 1, the passage rate of diborane gas is 74%, the passage rate of ozone gas is 25%, and the passage rate of ozone gas is suppressed to about 1/3 of the passage rate of diborane gas. From this result, it is understood that the sensitivity of the ozone gas can be lowered while suppressing the decrease in the sensitivity of the diborane gas by using the filter made of fluorine resin and the filter made of metal as the ozone gas removing means in the constant potential electrolysis type gas sensor. Further, it is understood that, by using the ozone gas removing means, the constant potential electrolysis type gas sensor can suppress the interference due to the ozone gas and can enhance the selectivity of the detection target gas.

  Looking at Example 2 in Table 1, the passage rate of diborane gas is 48%, the passage rate of ozone gas is 5%, and the passage rate of ozone gas is suppressed to about 1/10 of the passage rate of diborane gas. From this result, it is understood that the sensitivity of the ozone gas can be reduced while suppressing the decrease in the sensitivity of the diborane gas by using the fluorine resin filter as the ozone gas removing means in the constant potential electrolysis type gas sensor. Further, it is understood that, by using the ozone gas removing means, the constant potential electrolysis type gas sensor can suppress the interference due to the ozone gas and can enhance the selectivity of the detection target gas.

DESCRIPTION OF SYMBOLS 1 control-potential-electrolytic-type gas sensor 2 electrode 21 reaction pole 22 counter electrode 23 reference pole 3 electrolyte solution 4 container 41 inlet 41a one end of inlet 41b other end of inlet 42 electrolyte containing portion 43 outlet 43a flow One end of the outlet 43b The other end of the outlet 44 Inlet lid 45 O ring 46 Outlet lid 47 O ring 5 Diaphragm 6 Diaphragm 7 Ozone gas removal means 71 Fluororesin filter 72 Metal filter 8 Speed reduction means D Suction type gas detector I Gas inlet P gas suction means X direction

Claims (4)

A constant potential electrolytic gas sensor comprising: an electrode for detecting a gas to be detected; an electrolytic solution in contact with the electrode; and a container containing the electrode and the electrolytic solution,
The container includes an inlet for the measurement target gas including the detection target gas to flow into the container.
At the inlet, only ozone gas removing means that does not contain activated carbon and silica gel and has an adsorption ability of the gas to be measured that is lower than that of activated carbon and silica gel is provided as ozone gas removing means .
The ozone gas removing means includes a metal filter .
Constant potential electrolysis type gas sensor. The constant potential electrolytic gas sensor according to claim 1, wherein the ozone gas removing unit includes a fluorocarbon resin filter. A constant potential electrolytic gas sensor comprising: an electrode for detecting a gas to be detected; an electrolytic solution in contact with the electrode; and a container containing the electrode and the electrolytic solution,
The container includes an inlet for the measurement target gas including the detection target gas to flow into the container.
At the inlet, only ozone gas removing means that does not contain activated carbon and silica gel and has an adsorption ability of the gas to be measured that is lower than that of activated carbon and silica gel is provided as ozone gas removing means.
The ozone gas removing means includes a metal filter and a fluorine resin filter,
The fluorine resin filter and the metal filter are sequentially disposed from the upstream side to the downstream side of the inflow port,
Constant potential electrolysis type gas sensor. The inner side of the container at the inlet is provided with a diaphragm that prevents the electrolyte from flowing out of the container from the inlet;
The ozone gas removal means is provided on the outer side of the container at the inlet from the diaphragm.
The constant potential electrolysis gas sensor according to any one of claims 1 to 3 .

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