JP2019211293A - Starting method of gas sensor and gas sensor - Google Patents

Abstract

To provide a starting method of a gas sensor which can suppress deterioration in detection accuracy after standing.SOLUTION: The present disclosure is a starting method of a gas sensor including a catalyst unit, a sensor unit, and a high polymer material. The catalyst unit is configured to convert a first gas component included in gas to be measured into a second gas component. The sensor unit is configured to detect the second gas component in the gas to be measured passed through the catalyst unit. The high polymer material has reducibility and can generate auxiliary gas different from the first gas component and the second gas component at a downstream side of the catalyst unit in a flow direction of the gas to be measured by receiving heat. The starting method of the gas sensor includes a heating process for heating the high polymer material on the basis of input heat quantity to the high polymer material set according to a standing time before starting to detect the second gas component after a standing period when detection of the second gas component is not performed.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a gas sensor activation method and a gas sensor.

  As a gas sensor for measuring the concentration of a specific component in a gas to be measured, a gas sensor is known in which the concentration of a gas component is measured by a sensor element after chemically changing the component in the gas using a catalyst (see Patent Document 1). .

  In the gas sensor of Patent Document 1, a gas component to be measured is converted into a component that can be detected by a sensor element by a chemical change by a catalyst, and a miscellaneous gas component contained in the measurement target is removed by a chemical change such as combustion.

  In the gas sensor of Patent Document 1, a sensor element made of a metal oxide semiconductor is applied. As a type of gas sensor, a sensor element in which an electrode is provided on a solid electrolyte body, that is, a so-called solid electrolyte type sensor element is applied. There is also. This solid electrolyte type sensor element has a sensitivity that enables measurement of a gas component containing NOx at an extremely low concentration of several ppb to several hundred ppb level in the presence of a reducing gas.

  However, in a solid electrolyte type sensor element, the sensitivity may decrease due to a reduction in reducing gas. Therefore, for example, a part of the flow member for supplying the gas to be measured from the catalyst to the sensor element is configured using a polymer material capable of generating auxiliary gas having reducibility by receiving heat. Thus, the reducing gas can be supplied to the sensor element.

Japanese Patent Laid-Open No. 10-300702

  When the polymer material is left in a cold state without being heated, the auxiliary gas diffuses from the inside to the surface. For this reason, the discharge amount of the auxiliary gas after the start of the gas sensor may vary depending on the standing time before the start of the gas sensor. As described above, when the discharge amount of the auxiliary gas varies after the gas sensor is started, the sensitivity of the sensor element may vary, and the detection accuracy of the gas to be measured may decrease.

  An object of one aspect of the present disclosure is to provide a gas sensor activation method and a gas sensor that can suppress a decrease in detection accuracy after being left.

  As a result of intensive studies, the present inventors have found that even if the polymer material is left in a cold state by stopping the gas sensor (that is, stopping driving), by heating the polymer material, It was found that the state can be restored to the state at the time of use.

  One aspect of the present disclosure based on this finding is a gas sensor activation method including a catalyst unit, a sensor unit, and a polymer material. The catalyst unit is configured to convert a first gas component contained in the gas to be measured into a second gas component. The sensor unit is configured to detect a second gas component in the gas to be measured that has passed through the catalyst unit.

  In addition, the polymer material has reducibility and can generate an auxiliary gas different from the first gas component and the second gas component by receiving heat downstream of the catalyst unit in the flow direction of the gas to be measured. The starting method of the gas sensor is based on the amount of heat input to the polymer material set according to the standing time after the leaving period in which the second gas component is not detected and before the detection of the second gas component is started. A heating step for heating the polymer material is provided.

  According to such a configuration, the auxiliary gas in the polymer material is discharged before the detection of the gas sensor (that is, at the start-up) by heating the polymer material based on the input heat amount set according to the leaving period. The amount can be returned to the state in use of the gas sensor. As a result, since detection can be started under the supply of an appropriate auxiliary gas, it is possible to suppress a decrease in detection accuracy of the second gas component at the start-up after being left.

  In one embodiment of the present disclosure, the polymer material may be a polymer material containing fluorine. According to such a configuration, the auxiliary gas can be generated easily and reliably and supplied to the sensor element.

  In one aspect of the present disclosure, the gas sensor may include a heater configured to heat the polymeric material directly or indirectly. In the heating step, the polymer material may be heated using a heater. According to such a configuration, the discharge amount of the auxiliary gas in the polymer material at the time of activation can be adjusted by the heater included in the gas sensor.

In one aspect of the present disclosure, the measurement gas is exhaled, the first gas component is NO, and the second gas component may be NO _2. According to such a configuration, low-concentration nitrogen oxide (NOx) contained in exhaled breath can be diagnosed with high accuracy.

  Another aspect of the present disclosure is a gas sensor for measuring the concentration of a component contained in a gas to be measured. The gas sensor includes a catalyst unit, a sensor unit, a polymer material, a heater, and a control unit. The catalyst unit is configured to convert a first gas component contained in the gas to be measured into a second gas component. The sensor unit is configured to detect a second gas component in the gas to be measured that has passed through the catalyst unit.

  In addition, the polymer material has reducibility and can generate an auxiliary gas different from the first gas component and the second gas component by receiving heat downstream of the catalyst unit in the flow direction of the gas to be measured. The heater is configured to heat the polymeric material directly or indirectly. The control unit sets the amount of heat input to the polymer material according to the leaving time after starting the detection of the second gas component after the leaving period in which the detection of the second gas component is not performed. The polymer material is configured to be heated by driving the heater.

  According to such a configuration, by heating the polymer material based on the amount of heat input to the polymer material set according to the standing period, the auxiliary gas in the polymer material is The discharge amount can be returned to the state when the gas sensor is used. As a result, since detection can be started under the supply of appropriate auxiliary gas, it is possible to suppress a decrease in detection accuracy of the second gas component.

  In one aspect of the present disclosure, the control unit may have a function of acquiring the leaving time. According to such a configuration, the amount of heat input to the polymer material can be automatically calculated based on the standing time.

  One aspect of the present disclosure further includes an output unit capable of outputting at least one of a state in which the polymer material is heated by driving the heater and a state in which the second gas component can be detected. Also good. According to such a configuration, the user can easily confirm whether or not the gas sensor is in a state where gas detection is possible.

In one aspect of the present disclosure, the measurement gas is exhaled, the first gas component is NO, and the second gas component may be NO _2. According to such a configuration, a gas sensor capable of diagnosing low-concentration nitrogen oxide contained in exhaled breath with high accuracy is obtained.

It is a typical lineblock diagram showing the gas sensor of an embodiment. It is a typical block diagram which shows the gas sensor of embodiment different from FIG. It is a typical block diagram which shows the gas sensor of embodiment different from FIG.1 and FIG.2. It is a flowchart of the starting method of the gas sensor of embodiment. It is a typical block diagram which shows the gas sensor of embodiment different from FIG.1, FIG.2 and FIG.3.

Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
The gas sensor 1 shown in FIG. 1 is a gas sensor for measuring the concentration of a specific gas component contained in the gas G to be measured. Examples of the gas component to be measured by the gas sensor 1 include nitrogen oxide (NOx) and carbon dioxide.

  The gas sensor 1 can be used in fields such as environmental management, process management, and medical care. The gas sensor 1 can be suitably used for measuring a gas containing NOx at a low concentration of several ppb to several hundred ppb contained in exhaled breath, specifically for asthma diagnosis. In the present embodiment, the gas sensor 1 uses the gas to be measured G as expiration, and measures the concentration of the NOx component in the expiration.

  As shown in FIG. 1, the gas sensor 1 includes a catalyst unit 2, a sensor unit 3, a flow pipe 4 made of a polymer material, two heaters 5A and 5B, an introduction path 8A, and a discharge path 8B. And a housing 9.

<Catalyst unit>
The catalyst unit 2 includes a catalyst (not shown) for chemically changing the first gas component included in the gas G to be measured, and a first casing 2A that stores the catalyst.

The chemical change by the catalyst includes conversion of a certain component into another component and burning a certain component. Specifically, the catalyst converts the first gas component contained in the measurement gas G into the second gas component. Further, the catalyst burns miscellaneous gas components that the gas sensor 1 does not intend to measure the concentration. For example, in the case of asthma diagnosis, the catalyst converts NO to be measured into NO ₂ and burns CO. In other words, in this embodiment, the first gas component is NO, and the second gas component is NO _2.

  The first casing 2 </ b> A is disposed in a first space 9 </ b> A that is a closed space provided in the housing 9. The first casing 2A is provided with an introduction portion 2B and a discharge portion 2C that communicate the internal space of the first casing 2A with the outside of the first casing 2A.

  An introduction path 8A is connected to the introduction part 2B. A distribution pipe 4 to be described later is connected to the discharge part 2C. The gas G to be measured introduced from the introduction part 2B into the first casing 2A flows through the first casing 2A while being in contact with the catalyst, and is then discharged from the discharge part 2C into the flow pipe 4.

  The material of the first casing 2A is not particularly limited, but the first casing 2A has, for example, ceramic as a main component. Here, the “main component” means a component contained by 80% by mass or more.

  The catalyst of the catalyst unit 2 is carried, for example, on the inner surface of the first casing 2A or a carrier disposed in the first casing 2A. The catalyst unit 2 may have a gas flow path formed by a carrier. As the catalyst, for example, a noble metal such as platinum, palladium, rhodium, or gold, or a metal oxide such as manganese oxide, cobalt oxide, or tin oxide is used.

  A first heater 5A for heating the catalyst unit 2 is disposed in the first casing 2A. The first heater 5A is configured by metal wiring (that is, resistance) such as platinum. The first heater 5A generates heat when electric power is supplied from the outside.

<Sensor unit>
The sensor unit 3 includes a solid electrolyte type sensor element 3A for detecting a second gas component in the gas G to be measured that has passed through the catalyst unit 2, and a second casing 3B that houses the sensor element 3A.

  The sensor element 3A is a mixed potential type element in which an electrode reaction occurs between the second gas component and internal oxygen ions. The hybrid potential type sensor element 3A is well known and will not be described in detail. For example, the hybrid potential type sensor element 3A includes yttria stabilized zirconia (YSZ) and two electrodes, and outputs a potential difference between the two electrodes as a sensor signal. Have

  The second casing 3 </ b> B is disposed in a second space 9 </ b> B that is a closed space provided in the housing 9. The second casing 3B is provided with an introduction portion 3C and a discharge portion 3D that communicate the internal space of the second casing 3B with the outside of the second casing 3B.

  A distribution pipe 4 to be described later is connected to the introduction part 3C. A discharge path 8B is connected to the discharge unit 3D. The gas G to be measured introduced from the flow pipe 4 into the second casing 3B flows through the second casing 3B while being in contact with the sensor element 3A, and then discharged out of the system from the discharge section 3D via the discharge path 8B. Is done.

The material of the second casing 3B is not particularly limited, but the second casing 3B is made of, for example, stainless steel or a resin having heat resistance as a main component.
A second heater 5B for heating the sensor element 3A is disposed in the second casing 3B. The second heater 5B is configured by metal wiring (that is, resistance) such as platinum. The second heater 5B is electrically connected to the substrate disposed in the second casing 3B together with the sensor element 3A.

<Distribution pipe>
The flow pipe 4 constitutes a flow path of the measurement gas G between the catalyst unit 2 and the sensor unit 3. The flow pipe 4 is a member (that is, a tube) that connects the catalyst unit 2 and the sensor unit 3.

  The first end 4A of the flow pipe 4 is connected to the discharge part 2C of the first casing 2A. The second end 4B of the flow pipe 4 is connected to the introduction part 3C of the second casing 3B. In addition, the flow pipe 4 is disposed in a third space 9C that is a closed space provided in the housing 9, but a part of the second end portion 4B exists in the second space 9B.

  In the present embodiment, a polymer material (hereinafter also referred to as “specific polymer material”) that has reducibility and can generate auxiliary gas different from the first gas component and the second gas component by receiving heat. A distribution pipe 4 is configured. That is, the tube constituting the flow pipe 4 is entirely formed of a specific polymer material.

  The measured gas G heated by the first heater 5 </ b> A in the catalyst unit 2 passes through the flow pipe 4, so that the flow pipe 4 is heated and specified on the downstream side in the flow direction of the measured gas G from the catalyst unit 2. Auxiliary gas is generated from the polymer material. That is, the flow pipe 4 is indirectly heated by the first heater 5A. The auxiliary gas generated from the specific polymer material is supplied to the sensor unit 3 together with the measurement gas G.

  The distribution pipe 4 may contain a material other than the specific polymer material. Further, the flow pipe 4 may be formed of a material that does not include the specific polymer material, as long as at least a part of the inner peripheral surface (that is, a portion in contact with the measurement gas G) is formed of the specific polymer material. You may have a part.

  The specific polymer material is not limited as long as it can generate a reducing gas by receiving heat, but a fluorine-containing polymer material such as fluororubber or fluoroelastomer can be preferably used.

  Moreover, you may coat | cover the outer peripheral surface of the flow pipe 4 with the cylindrical heat insulation member 6 like the gas sensor 1A shown in FIG. The heat insulating member 6 is made of a heat insulating material such as glass fiber. In the gas sensor 1A of FIG. 2, the heat insulating member 6 suppresses the contact between the flow pipe 4 and the external atmosphere (that is, the atmosphere) of the gas sensor 1A. Therefore, it is not necessary to arrange the flow pipe 4 in the closed space for the purpose of suppressing the temperature drop of the flow pipe 4. That is, even when the third space 9C is open to the outside, the generation of auxiliary gas can be maintained.

  Furthermore, you may provide the 3rd heater 5C for heating the flow pipe 4 directly like the gas sensor 1B shown in FIG. The third heater 5C is a heating resistor similar to the first heater 5A and the second heater 5B. The third heater 5 </ b> C is disposed so as to cover at least a part of the outer peripheral surface of the flow pipe 4. In the gas sensor 1B of FIG. 3, since the flow pipe 4 is directly heated by the third heater 5C, the generation of auxiliary gas can be maintained even when the third space 9C is open to the outside.

<Control unit>
The control unit 10 includes a microprocessor and a storage medium such as a RAM and a ROM. The control unit 10 controls each heater by executing a program stored in advance.

  In addition, after the leaving period in which the detection of the second gas component is not performed, the control unit 10 waits for the leaving time of the gas sensor 1 (that is, the stop time of the gas sensor 1 before starting the detection of the second gas component, Control for heating the specific polymer material by driving the heater 5A or the heater 5C based on the set input heat amount. I do.

  Further, the control unit 10 has a function of acquiring the time for which the gas sensor 1 is left. As a method for acquiring the leaving time, the control unit 10 itself may have a counter or a clock, or the control unit 10 may receive an elapsed time measured by an external device.

  Specifically, when the gas sensor 1 is started from a cold state not accompanied by heating by a switch operation or the like, the control unit 10 first obtains a standing time from a state where the gas sensor 1 is stopped (that is, heating is stopped). . The control unit 10 itself may determine from the output of the sensor or the like that the gas sensor 1 is activated from the cold state, or the control unit 10 receives a signal from the outside notifying that the gas sensor 1 has been activated from the cold state. May be.

  Next, the control unit 10 sets the amount of heat input to the flow pipe 4 (that is, the specific polymer material) according to the standing time. This input heat amount is the product of the amount of heat received (that is, the energization amount to the heater) given to the flow pipe 4 per unit time and the heating time.

  As a method for setting the amount of heat input to the specific polymer material, the controller 10 changes (1) the amount of heat received with a constant amount of heat received, (2) changes the amount of heat received with a constant amount of heat, and (3) Either of changing the amount of heat received and the heating time can be adopted. Which setting method is adopted is appropriately determined depending on the configuration of the gas sensor 1 (for example, whether or not the heater energization amount can be controlled).

  The input heat amount may be determined using, for example, a table (that is, a matrix diagram) showing a relationship between the standing time and the input heat amount (that is, a combination of the received heat amount and the heating time), a function, an algorithm, or the like. The input heat amount may be calculated from the standing time using the following formula.

  When the input heat amount is determined, the control unit 10 drives the heater so that the amount of heat received is based on the input heat amount, and heats the flow pipe 4 during the heating time based on the input heat amount. This heating can be performed by driving the first heater 5 </ b> A and circulating the gas heated by the first heater 5 </ b> A into the flow pipe 4. Further, in the gas sensor 1B shown in FIG. 3, the flow pipe 4 can be heated using the third heater 5C.

  Further, the circulation pipe 4 may be heated using a heat source arranged outside the gas sensor 1, or the high-temperature gas heated outside the gas sensor 1 is circulated through the circulation pipe 4 and indirectly. May be heated.

  Table 1 shows the amount of outgas from the surface of the fluororubber after standing for a certain period of time and the amount of outgas from the surface of the fluororubber after heating the fluororubber after standing for a certain period of time at the temperature at which the gas sensor 1 is used. It is the result of measurement.

  As shown in Table 1, by heating, the surface state of the specific polymer material returns to the almost same state as when the second component was detected, and the discharge amount of auxiliary gas (that is, the outgas amount) is reduced and suitable for detection. (For example, the increase in outgas amount is within 30% of that before standing). In addition, the outgas amount in Table 1 is represented by a ratio where the outgas amount before being left is 1.

  As described above, the heating temperature of the flow pipe 4 before the detection of the second gas component can be set to the heating temperature by the first heater 5A, that is, the same temperature as when the second gas component is detected. In this case, the heating time corresponding to the standing time can be as follows, for example. When the standing time is 36 hours or less, the amount of input heat is zero, that is, the heating time is unnecessary. In this case, gas detection is started immediately without heating.

(Leaving time) Over 36 hours, 3 days or less (Heating time) 1 hour (Leaving time) Over 3 days, 2 weeks or less (Heating time) 2 hours (Leaving time) Over 2 weeks, 2 months or less (Heating time) 10 hours (Left Time) Over 2 months (Heating time) 48 hours

  However, the heating temperature of the flow pipe 4 may not necessarily be the same as that at the time of detecting the second gas component as long as the input heat amount can be achieved. Therefore, the specific polymer material having a temperature lower or higher than that at the time of detection of the second gas component may be heated. From the viewpoint, it is preferable to heat at the same temperature as when the second gas component is detected. In addition, the heating temperature of the flow pipe 4 may not be constant.

<Output unit>
The output unit 11 is in a first state in which a specific polymer material is heated by driving a heater in response to a signal input from the control unit 10 (that is, the heating time has not elapsed since the gas sensor 1 was started). State) and a second state in which the second gas component can be detected (that is, a state in which the heating time has elapsed since the start of the gas sensor 1) can be output.

  The output unit 11 includes a display device such as a display and a lamp, or a notification device such as a buzzer. For example, the output unit 11 may be a display that displays that fact in the first state and displays that fact in the second state. Here, an error display may be substituted for the display of the first state. The output unit 11 is a lamp that is turned off in the first state and turned on in the second state, or a lamp whose lighting state (color, blinking, etc.) changes between the first state and the second state. May be. Further, the output unit 11 may be a buzzer that emits a sound when the first state is switched to the second state, for example.

[1-3. effect]
According to the embodiment detailed above, the following effects can be obtained.
(1a) Before the gas sensor 1 starts detection (that is, at the start) by heating the flow pipe 4 made of the specific polymer material based on the amount of heat input to the specific polymer material set according to the leaving period. In addition, the discharge amount of the auxiliary gas in the specific polymer material can be returned to the state when the gas sensor 1 is used. As a result, since detection can be started under the supply of an appropriate auxiliary gas, it is possible to suppress a decrease in detection accuracy of the second gas component at the start-up after being left.

(1b) Since the control unit 10 has a function of acquiring the standing time, the amount of heat input to the specific polymer material can be automatically calculated or selected based on the standing time.
(1c) The output unit 11 allows the user to easily check whether or not the gas sensor 1 is in a gas detectable state.

[2. Second Embodiment]
[2-1. Constitution]
The starting method of the gas sensor shown in FIG. 4 is a method of starting the gas sensor in the left state. The gas sensor activation method of the present embodiment includes an input heat amount setting step S10 and a heating step S20.

  The gas sensor activation method of the present embodiment uses the gas sensors 1, 1A, 1B of FIG. 1, FIG. 2, or FIG. However, in the gas sensor activation method of the present disclosure, the gas sensors 1, 1 </ b> A, and 1 </ b> B are not necessarily used, and each process may be performed manually.

<Input heat amount setting process>
In this step, as described above, the amount of heat input to the specific polymer material is set according to the gas sensor leaving time. In addition, when performing next heating process S20 manually, this process can be abbreviate | omitted.

  As described above, the setting method of the amount of heat input to the specific polymer material includes (1) changing the heating time with the heat receiving amount constant, (2) changing the heat receiving amount with the heating time constant, and (3 ) Any one of changing both the amount of heat received and the heating time can be adopted.

<Heating process>
In this process, after the leaving period in which the second gas component is not detected, before the second gas component detection is started, the specific heat is applied based on the amount of heat input to the specific polymer material set according to the leaving time. Heat the polymeric material. The means for heating the specific polymer material may be a heater built in the gas sensor or an external heater.

[2-2. effect]
According to the embodiment detailed above, the following effects can be obtained.
(2a) Discharge of auxiliary gas in the specific polymer material before the start of detection of the gas sensor by heating the flow pipe 4 made of the specific polymer material based on the input heat amount set according to the leaving period The amount can be returned to the state in use of the gas sensor. As a result, since detection can be started under the supply of an appropriate auxiliary gas, it is possible to suppress a decrease in detection accuracy of the second gas component at the start-up after being left.

[3. Other Embodiments]
As mentioned above, although embodiment of this indication was described, it cannot be overemphasized that this indication can take various forms, without being limited to the above-mentioned embodiment.

  (3a) The gas sensor 1 of the above embodiment may not necessarily include a specific polymer material as a constituent material of the flow pipe 4. For example, a specific polymer material may be disposed as a part of the auxiliary gas supply unit 7 as in the gas sensor 1C illustrated in FIG.

  In the gas sensor 1C of FIG. 5, the catalyst unit 2 and the sensor unit 3 are disposed adjacent to each other. Specifically, the wall provided with the discharge port of the first casing 2A and the wall provided with the introduction port of the second casing 3B (that is, the wall on which the sensor element 3A is disposed) are joined by an adhesive or the like. Has been.

  The catalyst unit 2 and the sensor unit 3 are communicated with each other through a flow passage 14 constituted by a through hole provided in each casing. An auxiliary gas supply unit 7 is attached to the second casing 3 </ b> B of the sensor unit 3. That is, the auxiliary gas supply unit 7 is provided separately from the flow passage 14.

  The auxiliary gas supply unit 7 supplies auxiliary gas into the second casing 3B. The auxiliary gas supply unit 7 includes a specific polymer material, a tank 7A for storing the specific polymer material, a porous body 7B impregnated with the specific polymer material, and an auxiliary gas from the tank 7A into the second casing 3B. And a gas supply path 7C to be supplied.

  In the present embodiment, the specific polymer material is liquid when the gas sensor 1 is not used, that is, in a non-heated state, and is vaporized by heat transfer from the heater to become a reducing gas. As this compound, for example, γ-butyrolactone, acetophenone and the like are suitable.

  The tank 7A is screwed into the second casing 3B. The tank 7A is made of a metal such as aluminum or stainless steel (SUS). The porous body 7B is disposed inside the tank 7A. The porous body 7B has, for example, ceramic as a main component.

  The specific polymer material may be solid. Furthermore, the specific polymer material may be disposed in the second casing 3B.

  (3b) The gas sensor 1 of the above embodiment may include a single heater that heats the catalyst unit 2 and the sensor unit 3 simultaneously. For example, the gas sensor 1C in FIG. 5 includes a single heater 5D disposed in the sensor element 3A. By arranging the heater 5D in the sensor element 3A, it is possible to control the temperature of the sensor element 3A that needs to be controlled at a higher temperature than the catalyst unit 2.

  (3c) In the gas sensor 1 of the above-described embodiment, the control unit 10 does not necessarily have a function of acquiring the leaving time. That is, acquisition of the leaving time may be performed manually by the user.

  (3d) The gas sensor 1 of the above embodiment does not necessarily include the output unit 11. That is, the user may determine that the heating of the specific polymer material has been completed by means other than the output unit 11.

  (3e) The functions of one component in the above embodiment may be distributed as a plurality of components, or the functions of a plurality of components may be integrated into one component. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

1, 1A, 1B, 1C ... gas sensor, 2 ... catalyst unit, 2A ... first casing,
2B ... introducing section, 2C ... discharge section, 3 ... sensor unit, 3A ... sensor element,
3B ... 2nd casing, 3C ... introduction part, 3D ... discharge part, 4 ... distribution pipe, 4A ... 1st end part,
4B ... 2nd end, 5A, 5B, 5C, 5D ... heater, 6 ... heat insulation member,
7 ... auxiliary gas supply unit, 7A ... tank, 7B ... porous body, 7C ... gas supply path,
8A ... introduction path, 8B ... discharge path, 9 ... housing, 9A ... first space, 9B ... second space,
9C ... 3rd space, 10 ... Control part, 11 ... Output part, 14 ... Flow path.

Claims (8)

A catalyst unit configured to convert a first gas component contained in a gas to be measured into a second gas component;
A sensor unit configured to detect the second gas component in the gas to be measured that has passed through the catalyst unit;
A polymer material having a reducing property and capable of generating an auxiliary gas different from the first gas component and the second gas component by receiving heat downstream of the catalyst unit in the flow direction of the gas to be measured;
A gas sensor activation method comprising:
After the leaving period in which the detection of the second gas component is not performed and before starting the detection of the second gas component, based on the amount of heat input to the polymer material set according to the standing time, the polymer A method for starting a gas sensor, comprising a heating step of heating a material.   The gas sensor activation method according to claim 1, wherein the polymer material is a polymer material containing fluorine. The gas sensor comprises a heater configured to directly or indirectly heat the polymeric material,
The gas sensor activation method according to claim 1, wherein, in the heating step, the polymer material is heated using the heater. 4. The gas sensor activation method according to claim 1, wherein the gas to be measured is expiration, the first gas component is NO, and the second gas component is NO ₂ . A gas sensor for measuring the concentration of a component contained in a gas to be measured,
A catalyst unit configured to convert a first gas component contained in a gas to be measured into a second gas component;
A sensor unit configured to detect the second gas component in the gas to be measured that has passed through the catalyst unit;
A polymer material having a reducing property and capable of generating an auxiliary gas different from the first gas component and the second gas component by receiving heat downstream of the catalyst unit in the flow direction of the gas to be measured;
A heater configured to directly or indirectly heat the polymeric material;
After the leaving period in which the detection of the second gas component is not performed, before the detection of the second gas component is started, the amount of heat input to the polymer material is set according to the leaving time, and based on the amount of heat input A controller configured to heat the polymer material by driving the heater;
A gas sensor.   The gas sensor according to claim 5, wherein the control unit has a function of acquiring the standing time.   The output unit capable of outputting at least one of a state in which the heater is driven to heat the polymer material and a state in which the second gas component can be detected. The gas sensor according to claim 6. The measurement gas is exhaled, the first gas component is NO, and the second gas component is NO _2, the gas sensor according to any one of claims 7 claims 5.

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