JP2001208711A - Method and apparatus for detecting gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the temperature of a gas sensor 2 wherein a center electrode is embedded in an electrode periodically change, and to detect CH4 from the signal in a high temperature part, CO from the signal in a low temperature part, and an H2-containing gas from the initial signal of the low temperature part. SOLUTION: A CO/CH4 detector and CO/H2-containing gas detector can be manufactured on a common platform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to detecting three kinds of gases, that is, a combustible gas, a CO gas and a H2 containing gas, by using a gas sensor in which a center electrode is provided in a heater / electrode.

[0002]

2. Description of the Related Art A center electrode is disposed in a heater / electrode.
A gas sensor in which these are embedded in a metal oxide semiconductor such as SnO2 is known. Such a gas sensor is used for detecting CO, CH4, etc., and is used to periodically change the temperature of the gas sensor, detect CH4 by a signal of a high temperature part, and detect CO by a signal of a low temperature part. .

[0003] In addition to the detection of CO and CH4, there is a demand for detecting two types of gas leaks of H2-containing gas and generation of CO. The H2-containing gas is, for example, a mixture of H2 and CH4, and the mixing ratio varies. In such a case, CO / C
In the case of detecting H4, it is difficult to develop a CO / H2-containing gas detecting device by changing the composition and driving conditions of the gas sensor.

[0004]

A basic object of the present invention is to detect a CO / H2 gas containing CO / H2 gas by using a gas detection device of basically the same configuration under the same sensor and driving conditions as in the case of detecting CO / flammable gas. (Claims 1 to 9).
An additional object of the present invention is to set the gas detection device to two types of gas or one type of gas to facilitate the setting. An additional object of the present invention is to make it possible to detect an H2-containing gas even if the mixing ratio of H2 and flammable gas in the H2-containing gas changes over a wide range. A still further object of the present invention is to make it possible to detect a CO / flammable gas and a CO / H2 containing gas with a gas detection device having a common hardware configuration. An additional object of the invention of claim 6 is to enable temperature correction to three types of gas of CO / H2 containing gas / flammable gas by one temperature measuring means.

[0005]

The present invention uses a gas sensor in which a center electrode is provided inside a coil-shaped heater / electrode and these electrodes are embedded in a metal oxide semiconductor, and the heater power to the heater / electrode is supplied to the coil. In the method of detecting gas by periodically changing the temperature, when the combustible gas is detected from the signal of the high-temperature portion in the temperature pattern of the gas sensor corresponding to the periodic change of the heater power, and the temperature drops slightly from the high-temperature portion (2) detecting the H2-containing gas by the signal at (1) and detecting CO from the signal at the low temperature portion (claim 1). The combustible gas is, for example, CH4 or LPG. The H2-containing gas is, for example, H
2 and a mixture of CH4 and LPG.

Preferably, the gas sensor is exposed to a mixed gas of flammable gas and CO having a known concentration to experience the above-mentioned temperature pattern, a signal of a high-temperature part is stored as a standard for detecting a flammable gas, and a signal of a low-temperature part is stored. The signal is stored as a standard for CO detection, and the signal in the flammable gas at the high-temperature part is correlated with the signal in the H2-containing gas at a time when the temperature is slightly lowered from the high-temperature part, so that the signal in the high-temperature part is obtained. Corrected to H2
CO, flammable gas, and H2 containing gas are detected by storing as a standard for detecting contained gas and using each of the above standards (claim 2). Also preferably, the gas sensor is exposed to at least a mixed gas of flammable gas and H2 to experience the temperature pattern, and a signal at a time when the temperature is slightly lowered from a high temperature portion is stored as a standard for detecting the H2 containing gas. The signal obtained by correcting the signal in the high-temperature portion of the mixed gas at a predetermined ratio is stored as a standard for detecting flammable gas, and the flammable gas and the H2-containing gas are detected using the above-described respective standards. (Claim 3). Preferably, when any of the flammable gas and the H2-containing gas is detected, the gas is output as a gas leak (claim 4).

The present invention uses a gas sensor in which a center electrode is provided inside a coil-shaped heater / electrode and these electrodes are embedded in a metal oxide semiconductor, and the heater power to the heater / electrode is periodically changed. In a device for detecting a gas by changing the temperature, a combustible gas detecting means for detecting a combustible gas from a signal of a high temperature portion in a temperature pattern of a gas sensor corresponding to a periodic change of heater power, and a high temperature portion H2 containing gas detecting means for detecting the H2 containing gas with a signal at a time when the temperature is slightly lowered, and CO detecting means for detecting CO from the signal of the low temperature part are provided. Item 5).

Preferably, a temperature measuring means for measuring an ambient temperature, and a signal of the temperature measuring means, wherein CO, flammable gas,
A conversion means for converting into three kinds of correction coefficients for the H2-containing gas, for example, a three-column or three-row conversion table headed by a signal of the temperature measuring means is provided (claim 6). Preferably, means for storing a signal of a high-temperature part in a mixed gas of a flammable gas and a CO of a known concentration as a standard for detecting flammable gas, and storing a signal of a low-temperature part as a standard for detecting CO Means for converting the signal of the high-temperature portion into a standard for detecting the H2-containing gas, according to the conditions for converting the signal of the high-temperature portion to the signal in the H2-containing gas; and Means for storing the standard (claim 7). For the above-described storage, the variable resistance is adjusted and stored as a variable resistance value, or the variable resistance is stored in a nonvolatile memory such as an EEPROM. Also preferably,
Means for storing a signal at a time when the temperature is slightly lowered from a high temperature portion in a mixed gas of a combustible gas and H2 as a standard signal for detecting a H2 containing gas, Means for storing a signal converted under a predetermined conversion condition as a standard signal for combustible gas detection is provided (claim 8). Also preferably, a first notification means for notifying generation of CO by a detection signal of CO and a second notification means for notifying generation of combustible gas and generation of H2 containing gas without discriminating are provided. A mode in which the second notification means is driven only by the detection signal of the flammable gas, and the second signal is output by using either the detection signal of the flammable gas or the detection signal of the H2-containing gas.
A mode for driving the notification means can be freely selected (claim 9).

In the present invention, a standard (a gas sensor signal serving as a standard for determining a detection level) may be stored as a value of a variable resistor for setting, or electronically stored in an EEPROM, a DRAM unit with a backup battery, or the like. In particular, it is preferable to store the information in a nonvolatile manner as described above. The combustible gas is, for example, CH4, but may be LPG or the like. The H2-containing gas is, for example, H2
And CH4 or LPG.

[0010]

According to the present invention, the temperature of the gas sensor is periodically changed, the flammable gas is detected from the signal of the high-temperature portion, and the signal at the time when the temperature drops from the high-temperature portion by, for example, 30 ° C. or more is H2. Detects contained gas, and detects C
O is detected. The temperature change pattern of the gas sensor, the sampling point of the signal of the high temperature part, and the sampling point of the signal of the low temperature part may be the same as when detecting only the flammable gas and CO, and the same gas sensor is driven under the same driving conditions. Thus, an H2-containing gas can be detected in addition to the combustible gas and CO (claims 1, 5).

In the case of detecting three types of gases, ie, a combustible gas, an H 2 -containing gas, and CO, the time required to set up a gas detection device increases. Therefore, for example, the setting is performed with one type of setting gas using a mixed gas of CO and a flammable gas. In this case, the response waveform is determined by CO on the low temperature side, and is determined by the combustible gas on the high temperature side. Then, the signal of the high temperature part is stored as a standard for detecting combustible gas, and the signal of the low temperature part is stored as a standard for detecting CO. Next, as exemplified in FIG. 5, there is a strong correlation between the signal of the flammable gas in the high-temperature portion and the signal to the H2-containing gas at a time when the temperature is slightly lowered from the high-temperature portion. By converting the signal for the flammable gas at this correlation with this correlation, a standard for the H2 containing gas is obtained. As a result, three kinds of gases can be set by one kind of the gas mixture of the combustible gas and CO.
7).

When the gas sensor is exposed to a mixed gas of flammable gas and H 2, the signal at the time when the temperature is slightly lowered from the high temperature portion is that even if the ratio of flammable gas / H 2 in the mixed gas changes, the signal is It hardly changes, and is highly sensitive to the H2-containing mixed gas. Therefore, the signal at the time when the temperature is slightly lowered from the high temperature portion in the mixed gas is stored as a standard for detecting the H2 containing gas. In the high temperature part, the signal in the mixed gas is slightly smaller than the signal in the case of only the combustible gas. There is a strong correlation between the signal in the H2-containing gas (mixed gas) in the high-temperature section and the signal in the flammable gas in the high-temperature section, and the signal in the high-temperature section is converted based on this correlation. Thus, a standard for detecting flammable gas can be obtained (claim 3,
8). As a standard for detecting CO, the standard may be stored by exposing a gas sensor to a gas such as CO separately from a mixed gas of flammable gas and H2, or a mixture of flammable gas, H2 and CO The gas sensor may be exposed to gas. In this case, in the low temperature part, the magnitude of the signal differs between the case of only CO and the case of containing H2, so that the signal in the case of containing H2 in addition to CO is corrected to the signal of only CO. Remember.

In the detection of the H 2 -containing gas, a composition variation in a wide range from the ratio of the combustible gas in the gas close to 0% to almost 100% can be considered. In order to cope with such a case, it is preferable to output as a gas leak either when the flammable gas is detected in the high temperature portion or when the H2-containing gas is detected when the temperature is slightly lowered from the high temperature portion ( Claim 4).

According to the ninth aspect of the present invention, there is provided a first notifying means for notifying the generation of CO and a second notifying means for notifying the generation of the combustible gas and the generation of the H2 containing gas without discriminating. A mode in which the second notification means is driven by using only the detection signal of the flammable gas and not detecting the H2-containing gas or using the detection result even if the detection is performed; A mode for driving the second notification means is selectable for both the detection signal and the detection signal of the H2-containing gas, and the selection result is stored and fixed. In this case, the second notification means is driven only by the detection signal of the flammable gas, or is driven by both the detection signal of the flammable gas and the detection signal of the H2-containing gas, using substantially the same gas detection device. Mode can be selected, and with a common configuration, a CO / flammable gas detection device and a CO / H2 containing gas detection device,
Can be manufactured.

When three types of gases, that is, CO, a flammable gas, and a H2-containing gas, are detected, it is necessary to perform temperature correction for the three types of gases, that is, a CO-, H2-containing gas, and a flammable gas. Therefore, for example, one ambient temperature is measured by one temperature measuring means, and this signal is converted into three kinds of correction coefficients for CO, flammable gas, and H2 containing gas by the converting means. The temperature of the gas can be corrected (claim 6).

[0016]

1 to 5 show an embodiment. FIG. 1 shows the structure of the gas sensor 2. Reference numeral 4 denotes an inner core mainly composed of SnO2, and reference numeral 6 denotes an outer layer around the core, for example, a mixture of SnO2 and alumina. Reference numeral 8 denotes a coil-shaped heater / electrode, and reference numeral 10 denotes a center electrode that passes through the center of the coil of the heater / electrode 8. Note that the outer layer 6 may not be provided.

FIG. 2 shows the structure of the gas detector.
Is a power supply, R1 is a resistor, RL is a load resistor, and Th is a thermistor. Reference numeral 2 denotes the above-mentioned gas sensor, 14 denotes a switch for turning on / off a heater current to the heater / electrode 8, and 16 denotes a switch for applying a detection voltage VC between the electrodes 8 and 10. 20 is a microcomputer, 2
Reference numeral 2 denotes an EEPROM for storing various constants, usage history of the gas detection device, and the like. LED1 to LED3 are three types of LEDs, LED1 is a green LED for displaying power,
Lights up green when the power is on and the gas detector is operating normally. The LED 2 is a yellow LED for notifying the occurrence of CO. The LED 2 is lit yellow when CO is generated, and is kept lit until reset by a reset switch (not shown) or the like. LED3 is LE for notification of flammable gas generation
D indicates, for example, a red LED, which is turned on by generation of combustible gas, and is kept turned on until a reset switch (not shown) is turned on. BZ is a buzzer for alarm, C
An alarm is issued when O is generated or when H2 containing gas or combustible gas is generated, and Vout is a terminal for external output.

Reference numeral 24 denotes a bus of the microcomputer 20, and reference numeral 26 denotes a heater control unit. The heater / control electrode 8 is connected to the power supply 12 via the switch 14 at a predetermined duty ratio, and the duty ratio is changed between high and low. As a result, the heater power is changed between high and low. The change pattern of the heater power is, in addition to the two types of high and low, the power is applied only on the high temperature side and the power on the low temperature side is set to 0, or the heater power is changed according to a more complicated waveform such as a sine wave or a ramp wave. It may be changed. The VC control unit 28 processes the application of the detection voltage VC via the switch 16, and here applies the detection voltage by turning on the switch 16 only at a predetermined sampling point. Reference numeral 30 denotes an AD converter, which outputs a signal from the thermistor Th or the gas sensor 2.
Is converted from analog to digital. 32 is a temperature compensator, EE
Using the temperature coefficients for the three gases CO, CH4, and H2 stored in the PROM 22, correction coefficients for these three gases are generated. Reference numeral 34 denotes a timer that determines the periodic operation of the gas detection device. For example, here, one cycle is 20 seconds, of which the high temperature part is 5 seconds and the low temperature part is 15 seconds.

Reference numeral 36 denotes a mode-specific program storage unit. The gas detector of this embodiment detects CO / CH4 and CO / H2
-Detection of CH4 mixed gas (H2 containing gas). And with these, H2
Is different, and therefore the operation program is also different. Therefore, the storage unit 36 stores a program for detecting three kinds of gases of CO, CH4 and H2,
By skipping the part relating to the detection of H2 (omitting the sampling in the early part of the low-temperature part and the processing of the signal), it is possible to detect the two kinds of gases CO / CH4. Reference numeral 38 denotes a setting processing unit, which is an input from a dip switch or a jumper wire (not shown). This mode is started, and a standard signal obtained at the time of setting is transmitted to an EEPROM.
22 is stored as an alarm level. 40 is EEP
An EEPROM control unit that reads and writes data from and to the ROM 22.

Reference numeral 42 denotes a CO detection unit which detects CO from a signal of the low temperature unit, for example, immediately before the end, and performs EEPRO for temperature correction.
Using the temperature correction coefficient for CO stored in M22, reference numeral 44 denotes a CH4 detecting unit, for example, a C4 signal from a signal immediately before the end of the high-temperature portion.
H4 is detected, and the temperature correction uses the correction coefficient similarly stored in the EEPROM 22. Reference numeral 46 denotes an H2 detecting section, which detects H2 from, for example, an initial signal of a low temperature section, and a coefficient for temperature correction is similarly stored in the EEPROM 22. Reference numeral 48 denotes an external output unit, which includes the LED1 to LED3 and the buzzer BZ.
Drive etc.

Various data are stored in the EEPROM 22, and these data can be rewritten and read out via the EEPROM control unit 40. The usage time integrating unit 50 stores the integrated value of the time used by turning on the power of the gas detection device, and the alarm history storage unit 52 stores, for example, the contents of the alarm such as the last 10 times, , Flammable gas or H2-containing gas detection) is stored in the conversion rate storage unit 54, for example, from the detection signal of CH4 in the high-temperature part to the signal to the H2-containing gas of the same concentration in the early part of the low-temperature part. The conversion rate for converting the signal of the H2-containing gas in the high-temperature portion to the signal for CH4 in the high-temperature portion is stored. This conversion factor is used to simplify setting of two types of gases, that is, a combustible gas and an H2-containing gas, to one type of gas. The temperature coefficient storage unit 56 stores CO,
The temperature coefficients for the three kinds of gases including CH4 and H2 are stored, the temperature coefficient is obtained from the ambient temperature obtained by the thermistor Th, and this is used as a correction coefficient by the temperature correction unit 32. The temperature coefficient of H2 and the temperature coefficient of the H2-containing gas are substantially equal. 58 is an alarm level storage unit which stores CO, CH4, H2.
The alarm levels (standard signals for performing alarms) for the three types of contained gases are stored. These alarm levels are stored by setting. If only two types of gases, CO and CH4, are detected, the alarm levels to be stored are also two types. If two types of gases, CO and H2 containing gas, are detected, CO is detected. , CH4 and H2 containing gas are stored. Reference numeral 60 denotes a mode storage unit.
When the operation mode of the gas detection device is CO / CH4 detection,
The detection of the detection of the CO / H2 containing gas is stored.

FIG. 3 shows operation waveforms of the gas sensor 2. The gas sensor 2 operates at, for example, one cycle of 20 seconds.
The second is a high temperature part (maximum temperature of less than 500 ° C.), the 15 second is a low temperature part (minimum temperature of about 80 ° C.), and the heater power PH applied to the heater electrode 8 changes in a square wave as shown in 1) of FIG. I do. As shown in 2) of FIG. 3, the detection voltage VC is applied at three points, that is, a detection point of CO, a detection point of CH4, and a detection point of H2-containing gas (the initial stage of the low temperature part). The signal of the sensor (shown as if the detection voltage VC is being continuously applied) changes as shown in 3) of FIG.
It is a waveform in a contained gas. Then, sensor signals are sampled at three detection points, and CO and CH are sampled from these.
4, and three types of gas, H2 containing gas, are detected. However, if the operation mode stored in the mode storage unit 60 is CO / CH4
Is detected, no detection voltage is applied at the detection point of the H2-containing gas, and only two types of sampling, the CO signal and the CH4 signal, are sampled.

In the temperature change pattern of the gas sensor 2, the temperature of the high temperature part is preferably, for example, about 400 to 550 ° C., and the temperature of the low temperature part is preferably about room temperature to 150 ° C.
The temperature at the detection point of the H2-containing gas is, for example, 200 to
The temperature is preferably about 400 ° C., more preferably, for example, 30 ° C. or more lower than the temperature at the CH 4 detection point. In the case of FIG. 3, the detection point of CH4 is, for example, 1 after the start of the high temperature section.
The detection point of the H2 containing gas is preferably a signal at a time point of 0.5 to 5 seconds after the start of the low temperature part, and a signal at a time point of 0.5 to 3 seconds is particularly preferable. The signal is preferable, and the signal for detecting CO
The signal after 15 seconds has passed is preferred.

FIG. 4 shows a waveform of the sensor resistance in a 1: 1 mixed gas of CO, H2, CH4, H2 + CH4. In this specification, the unit of the gas concentration is volppm, the unit of the sensor resistance is kΩ, and the high-temperature portion is from 5 seconds immediately after the lapse of 0 seconds, and the low-temperature portion is from 0 seconds thereafter.

As is apparent from FIG.
And the waveform for the mixed gas of H2 and CH4 are almost the same. For example, if CH4 is contained in 30% or more, the same signal is obtained even if the CH4 content changes. As described above, the detection signal for the H2 containing gas in the low-temperature section (here, at the 6th second) is a reliable signal even when the ratio of H2 to the flammable gas changes, High selectivity. In the high temperature part, the signal in the case of 100% H2, the signal of the mixed gas of H2 and CH4, and the signal of the case of only CH4 are different from each other, and among these, the signal in the case of the mixed gas of CH4 and H2 is different. , CH4 only.
Therefore, if a mixed gas of H2 and CH4 is used, the signal of only H2 and the signal of the mixed gas of H2 and CH4 match in the early stage of the low temperature part, and the signal of the mixed gas of H2 and CH4 in the high temperature part. It can be converted to a signal for only CH4. Although not shown in the figure, the mixed gas of CO-CH4
The waveform in the case of only O and the waveform in the case of CH4 100% are merely generated by being superimposed. That is, CO and C
There is almost no waveform interference with H4.

Although not shown in FIG. 4, the waveform of the gas in which the three types of CO, CH4, and H2 are mixed shows that H2 in the initial period of the high-temperature portion to the low-temperature portion (about 2 seconds after the transition to the low-temperature portion). And the waveform of the mixed gas of CH4 and thereafter, the sensor resistance becomes smaller than that of the waveform of the CO gas of the same concentration.

FIG. 5 shows the correlation of the sensor signals between the fifth second in FIG. 4 (the last point of the high-temperature part) and the sixth second in FIG. 4 (the first second in the low-temperature part). In the figure, the resistance value in 3000 ppm of CH4 is a signal in the high temperature part, and the resistance value in 3000 ppm of H2 is a signal in the early part of the low temperature part, and these are almost on a straight line. Therefore, by storing the conversion coefficient between them in the conversion rate storage unit 54, a standard signal to H2 in the early part of the low temperature part is generated from the standard signal to CH4 in the high temperature part, or the H2 content in the high temperature part is changed. From the standard signal for gas, the CH4
A standard signal can be generated.

The mode storage unit 60 stores a mode of detecting CO / flammable gas or detecting CO / H2-containing gas / CH4. The conversion rate, the temperature coefficient, and the like are fixed and stored in the EEPROM 22 in lot units of the gas sensor 2 or over a plurality of lots, and the gas standard signal obtained at the time of setting is stored as the alarm level.

When detecting two types of gases, CO and CH4, a gas detector is set using a mixed gas of CO and CH4, a standard signal for CO detection is obtained from a signal at a low temperature part, and a standard signal for CO detection is obtained at a high temperature part. A standard signal for detecting CH4 may be obtained from the signal of (1) and stored in the alarm level storage unit 58. On the other hand, when detecting three kinds of gases of CO / H2 containing gas / CH4, as shown in FIG. 3, the points at which VC is added are three points just before the end of the low-temperature part, immediately before the end of the high-temperature part, and at the beginning of the low-temperature part. For example, using a mixed gas of CO and CH4 (for example, 300 ppm of CO + 3000 ppm of CH4),
The signal to CH4 in the high temperature section is converted into an alarm level to H2 in the initial stage of the low temperature section by the conversion rate stored in the conversion rate storage section 54 and stored in the alarm level storage section 58. Alternatively, a mixed gas of CH4 and H2 is used, and the detection signal at the beginning of the low-temperature section is stored as a standard signal to the H2-containing gas, and the signal to CH4 at the high-temperature section is stored at the high-temperature section. Calculated from the detection signal to the gas, CH4
Store as alarm level to Apart from this, C
The temperature of the gas sensor 2 is changed in O, and a standard signal for detecting CO is obtained from the signal to the low temperature part and stored. In this way, the alarm levels for three types of gases can be set by one or two setting operations. The reason why CH4 is detected for detecting the H2 containing gas is to detect the same even when the CH4 content in the H2 containing gas is 100%.

[Brief description of the drawings]

FIG. 1 is a diagram showing a gas sensor used in an embodiment.

FIG. 2 is a block diagram of a gas detector according to the embodiment.

FIG. 3 shows 1) heater power P in the gas detector of the embodiment.
H, 2) Circuit voltage VC, 3) Waveform diagram showing waveform of sensor output VRS

FIG. 4 is a diagram showing a resistance value RS of a gas sensor in CO, H2, CH4, and a mixed gas of H2 and CH4 in the embodiment.

FIG. 5 shows CH at the final point of the high-temperature part in the embodiment.
Resistance value to 43000ppm and H2300
Diagram showing correlation with resistance value to 0 ppm

[Explanation of symbols]

 2 Gas sensor 4 Inner core 6 Outer layer 8 Heater / electrode 10 Center electrode 12 Power supply 14, 16 switch 20 Microcomputer 22 EEPROM 24 Bus 26 Heater control unit 28 VC control unit 30 AD converter 32 Temperature correction unit 34 Timer 36 Mode program storage unit 38 Setting processing unit 40 EEPROM control unit 42 CO detection unit 44 CH4 detection unit 46 H2 detection unit 48 External output unit 50 Usage time integration unit 52 Alarm history storage unit 54 Conversion rate storage unit 56 Temperature coefficient storage unit 58 Alarm level storage unit 60 Mode Storage unit Th thermistor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G046 AA02 AA05 AA11 AA19 BA02 BC03 BE02 CA09 DA04 DB05 DB08 DC02 DC12 DC14 DC16 DC17 DC18 DD01 EA03 EA09 EA11 EB06 FB02 FC01 FE03 FE39

Claims (9)

[Claims] 1. A gas sensor in which a central electrode is disposed inside a coil-shaped heater / electrode and these electrodes are embedded in a metal oxide semiconductor, and heater power to the heater / electrode is periodically changed. In the gas detection method, the flammable gas is detected from the signal of the high temperature part in the temperature pattern of the gas sensor corresponding to the periodic change of the heater power, and the signal at the time when the temperature is slightly lowered from the high temperature part is used. A gas detection method comprising detecting an H2-containing gas and detecting CO from a signal of a low temperature portion. 2. Exposure of the gas sensor to a mixed gas of flammable gas and CO having a known concentration to cause the temperature pattern to be experienced, storing a signal of a high-temperature portion as a standard for detecting a flammable gas; As a standard for CO detection,
A signal obtained by correcting the signal in the high-temperature portion by detecting the correlation between the signal in the flammable gas at the high-temperature portion and the signal in the H2-containing gas at a time when the temperature is slightly lowered from the high-temperature portion is used for detecting the H2-containing gas. Is stored as a standard, and using each of the above standards, C
2. The gas detecting method according to claim 1, wherein O, flammable gas, and H2 containing gas are detected. 3. The gas sensor is exposed to at least a mixed gas of flammable gas and H2 to experience the temperature pattern.
It stores as a standard for detecting the contained gas, and stores the signal obtained by correcting the signal in the high-temperature portion at a predetermined ratio as a standard for detecting the flammable gas. The gas detection method according to claim 1, wherein the method includes detecting a contained gas. 4. The gas detection method according to claim 1, wherein when any one of the combustible gas and the H 2 -containing gas is detected, the gas is output as a gas leak. 5. A gas sensor in which a central electrode is disposed inside a coil-shaped heater / electrode and these electrodes are embedded in a metal oxide semiconductor, and heater power to the heater / electrode is periodically changed. Then, in the gas detecting device, a flammable gas detecting means for detecting a flammable gas from a signal of a high-temperature portion in a temperature pattern of a gas sensor corresponding to a periodic change of heater power; A gas detecting device, comprising: a H2 containing gas detecting means for detecting an H2 containing gas with a signal at the time of a temperature decrease; and a CO detecting means for detecting CO from a signal of a low temperature part. . 6. A temperature measuring means for measuring an ambient temperature,
6. The gas detection device according to claim 5, further comprising a conversion unit for converting the signal of the temperature measurement unit into three types of correction coefficients for CO, flammable gas, and H2 containing gas. 7. A means for storing a signal of a high temperature part in a mixed gas of a combustible gas and a CO of a known concentration as a standard for detecting a combustible gas, and a signal for detecting a signal of a low temperature part in a CO gas. The signal of the high temperature part is converted to H by the means for storing the signal as
6. The gas detection device according to claim 5, further comprising: means for converting into a standard for detecting 2 content gas; and means for storing the standard for detecting the H2 content gas. 8. A means for storing, as a standard signal for detecting an H2-containing gas, a signal in a mixed gas of a combustible gas and H2 at a time when the temperature is slightly lowered from a high-temperature portion, 6. A gas detecting apparatus according to claim 5, further comprising means for storing a signal obtained by converting a signal under predetermined conversion conditions as a standard signal for detecting combustible gas. 9. A first notifying means for notifying generation of CO by a detection signal of CO, and a second notifying means for notifying the generation of combustible gas and the generation of H2 containing gas without discriminating. A mode in which the second notification means is driven only by the detection signal of the flammable gas, and a mode in which the second notification means is driven by any of the detection signal of the flammable gas and the detection signal of the H2-containing gas. 6. The gas detection device according to claim 5, wherein the gas detection device is free.