JP2017167580A - Fire detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fire detector which can determine the state of a fire early without malfunctioning.SOLUTION: The fire detector includes: at least one gas sensor for detecting at least two types of gases which are changed by a fire; and a controller circuit for processing an output signal from the gas sensor and controlling the gas sensor, the controller circuit having determination means for determining a fire from changes in the concentrations of at least two types of gases. The gas sensor includes at least one gas sensor detecting a carbon monoxide gas and a carbon dioxide gas. The determination unit may determine a fire based on the increase rate of concentrations of the carbon monoxide gas and the carbon dioxide gas.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fire detection device.

  The fire alarm device detects smoke generated due to a fire or heat (temperature) that changes due to a fire. When the smoke concentration or temperature exceeds a judgment threshold, sound, buzzer sound, lamp, etc. This is an alarm device. In such a fire alarm device, there has been a problem of misjudging a fire by detecting smoke, heat, etc. generated by factors other than fire such as cooking and smoking. In order to avoid this erroneous determination, a fire alarm device including a fire sensor that detects smoke and heat and a gas sensor that detects a fire-generated gas has been proposed.

  For example, Patent Document 1 discloses a fire sensor that outputs a signal according to the degree of smoke or heat generated by a fire, a gas sensor that outputs a signal according to the concentration of a fire-generated gas generated by a fire, and a fire sensor. And determining means for determining a fire based on the signal output of the gas sensor, and alarm means for alarming based on the result of the determining means.

  In the fire determination method described in Patent Document 1, the signal output of the fire sensor is classified by four thresholds, and the signal output of the gas sensor is also classified by three thresholds, and the result of the combination classified by these thresholds. Therefore, malfunctions can be prevented by classifying them into four states: no abnormality state, gas abnormality state, fire source confirmation necessary state, and fire state.

Japanese Patent No. 4568591

  By the way, it is known that the fire sensor that detects smoke and heat, as in Patent Document 1, delays the determination of the fire state compared to the case where the gas sensor that detects the concentration of the fire-generated gas generated by the fire is used. Yes. Generally, a gas sensor that detects carbon monoxide gas is used as the gas sensor. The determination of the fire condition is delayed in the order of carbon monoxide gas detection, smoke detection, and heat detection. Many fire accidents are due to delays in escape. Early detection and early escape are ways to protect yourself from accidents.

  However, although the fire alarm device shown in Patent Document 1 uses a carbon monoxide gas sensor as a gas sensor and a heat sensor as a fire sensor, the fire state is determined only by the heat sensor. Even if the signal output of the thermal sensor is low (temperature is lower than the threshold value for judging the fire condition), if the concentration of carbon monoxide gas is high, it is necessary to confirm the fire source. The concentration of is ignored. Conversely, when a fire condition is determined only with a carbon monoxide gas sensor, a malfunction may occur. Since carbon monoxide gas is a dangerous gas that causes carbon monoxide poisoning, it is meaningful to prevent carbon monoxide poisoning when it is judged only with a carbon monoxide gas sensor. Cannot judge.

  This invention is made | formed in view of such a problem, and it aims at providing the fire detection apparatus which can determine a fire state early and without malfunctioning.

In order to solve the above problems, a fire detection device according to the present invention includes at least one gas sensor that detects at least two types of gas that changes during a fire, controls the gas sensor, and processes an output signal from the gas sensor. A control processing circuit;
The control processing circuit includes determination means for determining a fire from the concentration change of the at least two kinds of gases.

  With the above configuration, without using a fire sensor that detects smoke, heat, etc., to detect a fire condition early because the fire status is judged only by the concentration of two or more types of fire-changing gas whose concentration changes due to a fire. Is possible. Furthermore, since it determines with the density | concentration of two or more types of change gas at the time of a fire, malfunction can be prevented.

  The gas sensor of the present fire detection device includes one or more gas sensors that detect carbon monoxide gas and carbon dioxide gas, and the determination means includes an increase rate of the concentration of carbon monoxide gas and a concentration of the carbon dioxide gas. It is characterized by determining a fire from the rate of increase. In the event of a fire, carbon monoxide gas and carbon dioxide gas are generated. Therefore, it is possible to determine the fire state early and without malfunctioning by detecting the increase in the concentration of these two gases.

  Furthermore, the determination means determines that a fire occurs when the concentration increase rate of the carbon monoxide gas and the concentration increase rate of the carbon dioxide gas are substantially equal. The concentrations of carbon monoxide gas and carbon dioxide gas in the initial fire are different in absolute value, but rise linearly in a short period of time. Can be judged.

  The gas sensor includes a heat conduction type gas sensor that detects carbon dioxide gas. The carbon dioxide gas detection is generally an optical gas sensor called NDIR (Non Dispersive InfraRed, non-dispersive infrared sensor), but it is possible to reduce the size by using a heat conduction type.

The control processing circuit has heating means for heating the thermosensitive element of the gas sensor at at least two different temperatures, and storage means for storing gas concentration sensitivity corresponding to the temperature, and the output signal of the gas sensor and the gas concentration A gas concentration calculating means for calculating the gas concentration from the sensitivity is provided. In general, a heat conduction type gas sensor does not have gas selectivity, but by using this method, it is possible to give selectivity to carbon dioxide gas.

  This fire detection device is characterized in that the gas sensor and the control processing circuit are housed in one package. Specialization is required to handle the gas sensor at the element level, but the fire detection device can be accommodated in a single package to meet the needs of modularization.

  ADVANTAGE OF THE INVENTION According to this invention, the fire detection apparatus which can determine a fire state early and without malfunctioning can be provided.

It is a schematic structure figure showing a fire detection device concerning a 1st embodiment of the present invention. It is a schematic sectional drawing which shows the fire detection apparatus which concerns on the 1st Embodiment of this invention. It is a schematic block diagram which shows the control processing circuit which is a component of the fire detection apparatus which concerns on the 1st Embodiment of this invention. It is a graph which shows the relationship between the gas concentration which changes with the fire of a building, and time. It is a graph which shows the relationship between the alarm time by the smoke and heat (temperature) which generate | occur | produce at the time of a fire, the fire state determination by carbon monoxide gas, or an alarm time. It is a schematic block diagram which shows the fire alarm apparatus which concerns on the comparative example 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

(First embodiment)
First, with reference to FIG. 1, the structure of the fire detection apparatus 100 which concerns on the 1st Embodiment of this invention is demonstrated. FIG. 1 is a schematic configuration diagram illustrating a fire detection device according to a first embodiment of the present invention.

  As shown in FIG. 1, the fire detection device 100 includes a first gas sensor 101, a second gas sensor 102, and a control processing circuit 103.

  The first gas sensor 101 outputs an output signal VO1 corresponding to the concentration of the first fire change gas G1 whose concentration changes due to a fire to the control processing circuit 103. Examples of the first gas sensor 101 include a catalytic combustion type gas sensor, a semiconductor type gas sensor, a heat conduction type gas sensor, an NDIR type gas sensor, and an electrochemical type gas sensor. The first fire change gas G1 is a gas whose concentration changes due to a fire, such as carbon monoxide gas, carbon dioxide gas generated by a fire, oxygen whose concentration decreases due to a fire, and the like.

  The second gas sensor 102 outputs to the control processing circuit 103 an output signal VO2 corresponding to the concentration of the second fire change gas G2 whose concentration changes due to a fire. Similar to the first gas sensor 101, the second gas sensor 102 includes a catalytic combustion type gas sensor, a semiconductor type gas sensor, a heat conduction type gas sensor, an NDIR type gas sensor, an electrochemical type gas sensor, and the like. The second fire change gas G2 is a gas whose concentration changes due to the fire as with the first fire change gas, and the concentration is reduced by the carbon monoxide gas, carbon dioxide gas, and fire generated by the fire. There is oxygen, etc., but it is different from the first fire changing gas.

  The control processing circuit 103 receives the output signals (VO1, VO2) corresponding to the concentrations of the changing gas at the time of fire from the first gas sensor 101 and the second gas sensor 102, and performs arithmetic processing on the input signals (VO1, VO2). The result is output as an output signal VO5. The arithmetic processing is performed by correcting the influence of the electrical signal, temperature, and humidity determined as a fire state from the temporal relationship between the output signal VO1 of the first gas sensor 101 and the output signal VO2 of the second gas sensor 102. Is output as an output signal VO5. By connecting alarm means (not shown) such as sound, buzzer sound, and lamp to the fire detection apparatus 100, a fire alarm apparatus can be obtained.

  The control processing circuit 103 includes output signals (VO3, VO4) for controlling the first gas sensor 101 and the second gas sensor 102. For the control, the first gas sensor 101 and the second gas sensor 102 are intermittently driven to reduce power consumption, and in the case of a gas sensor with a heater, heater control is performed.

  FIG. 2 is a schematic cross-sectional view showing the fire detection device according to the first embodiment of the present invention. The fire detection device 200 includes a first gas sensor 101, a second gas sensor 102, a control processing circuit 103, and a package 202.

  In the first embodiment, the first gas sensor 101 is described as a heat conduction type gas sensor that detects carbon dioxide, and the second gas sensor 102 is described as a contact combustion type gas sensor that detects carbon monoxide. An NDIR gas sensor, an electrochemical gas sensor, or the like may be used. As for the gas, the first fire change gas G1 will be described as carbon dioxide gas, and the second fire change gas G2 will be described as carbon monoxide gas. I do not care.

  Output signals of the first gas sensor 101 and the second gas sensor 102 are connected to the package electrode 203 via the bonding wire 207, the package internal electrode 205, and the package electrode through hole 204. An output signal of the control processing circuit 103 is connected to the package electrode 203 via the metal bump 206, the package internal electrode 205, and the package electrode through hole 204. Further, an output signal for controlling the gas sensor (101, 102) of the control processing circuit 103 is connected via the metal bump 206, the package internal electrode 205, and the bonding wire 207. The package 202 has a vent hole 201.

  The first gas sensor 101 has a configuration in which a microheater 211 covered with an insulating layer 208 is placed on a gas sensor substrate 210 and a thermal element 213 covered with an insulating layer 214 is further stacked. The gas sensor substrate 210 below the microheater 211 is a hollow cavity 212 in order to increase the thermal efficiency of the microheater 211. The gas sensor electrode 216 is connected to the thermal element 213 so that an electric signal can be taken out from the thermal element 213, and a part of the gas sensor electrode 216 is exposed so as to be connected to the bonding wire 207.

  The second gas sensor 102 has a configuration in which a microheater 211 covered with an insulating layer 208 is placed on a gas sensor substrate 210 and a thermal element 213 covered with an insulating layer 214 is further stacked. The gas sensor substrate 210 below the microheater 211 is a hollow cavity 212 in order to increase the thermal efficiency of the microheater 211. The gas sensor electrode 216 is connected to the thermal element 213 so that an electric signal can be taken out from the thermal element 213, and a part of the gas sensor electrode 216 is exposed so as to be connected to the bonding wire 207. The structure is the same as that of the first gas sensor 101 except that a catalyst 215 is further stacked on the insulating layer 214.

  Since the base portion of the microheater 211 covered with the gas sensor substrate 210 and the upper insulating layer 208 of the first gas sensor 101 and the second gas sensor 102 has the same structure, the two gas sensors (101, 102) are integrated. It has a structure.

  The control processing circuit 103 is an integrated circuit such as an ASIC (Application Specific Integrated Circuit). Gas sensors (101, 102) are arranged on the control processing circuit 103 for miniaturization.

  FIG. 3 is a schematic configuration diagram showing a control processing circuit which is a component of the fire detection device according to the first embodiment of the present invention. The control processing circuit 103 includes a storage unit 301, a gas concentration calculation unit 302, a heating unit 303, and a determination unit 304. Based on the output signals (VO1, VO2) of the gas sensors (101, 102) and the output signal of the storage means 301, the gas concentration calculating means 302 calculates the gas concentration. The output signal of the gas concentration calculation means is input to the determination means 304 to determine the fire condition, and the determination result is output from the output signal VO5. The heating means 303 heats the thermal element temperature in the heat conduction type gas sensor and the sensor of the contact combustion type gas sensor.

  With reference to FIG. 2, the material of the fire detection apparatus 200 which concerns on the 1st Embodiment of this invention is demonstrated. The gas sensor substrate 210 of the first gas sensor 101 and the second gas sensor 102 is not particularly limited as long as it has a suitable mechanical strength and is suitable for fine processing such as etching. For example, a silicon single crystal substrate, a sapphire single crystal substrate, a ceramic substrate, a quartz substrate, a glass substrate, or the like is suitable. The insulating layers (208, 214) are not particularly limited as long as the insulating layers (208, 214) have appropriate mechanical strength and can be easily formed by a known thin film process. A nitride film or the like is preferable. The microheater 211 has a heat resistance that can withstand heat treatment in the process, and is preferably a relatively high melting point material having appropriate conductivity. For example, molybdenum (Mo), platinum (Pt), gold (Au) Tungsten (W), tantalum (Ta), palladium (Pd), iridium (Ir), or an alloy containing two or more of these metals is preferable. The thermosensitive element 213 is preferably a thermistor having a negative temperature coefficient such as a composite metal oxide. Alternatively, a temperature measuring body such as platinum (Pt) or nickel (Ni) having a certain temperature coefficient may be used. The catalyst 215 of the second gas sensor 102 is preferably a combustion catalyst in which a catalyst metal such as platinum (Pt) or palladium (Pd) is supported by alumina. The bonding wire 207 is preferably a metal wire having a low resistance such as Au, Al, or Cu. The metal bump 206 has an appropriate conductivity and can be connected between the ASIC electrode and the internal electrode of the package. For example, gold or solder is generally used. The gas sensor electrode 216, the package internal electrode 205, the package electrode through hole 204, and the package electrode 203 are made of a material that can be easily electrically connected, such as aluminum (Al), copper (Cu), gold (Au), platinum (Pt), and the like. Is suitable, and may be laminated as necessary. The package 202 may be partially combined such that ceramic, resin, metal, or the lid portion with the vent hole 201 is metal and the other body is ceramic.

Next, the operation of the heat conduction type gas sensor will be described. The first gas sensor 101 is a heat conduction type gas sensor that detects carbon dioxide, and detects the concentration of carbon dioxide gas using a difference in thermal conductivity between carbon dioxide gas and air. As shown in Table 1, the thermal conductivity of carbon dioxide gas is 0.0306W / mK (at 200 ° C), which is different from the thermal conductivity of air 0.0386W / mK (at 200 ° C). As the temperature rises, the temperature of the thermal element 214 also rises. In the case where the thermal element 213 is an NTC (Negative Temperature Coefficient) thermistor having a negative temperature coefficient, the thermistor resistance value decreases, and this is input to the control processing circuit 103 as an electric signal to calculate the concentration. The thermal element 213 is generally connected in series with a load resistor (not shown), and the voltage at the connection point with the load resistor is used as an electrical signal. The load resistance may be formed on the gas sensor substrate or may be formed on the control processing circuit 103.

  Since the heat-conducting gas sensor of the first gas sensor 101 has no gas selectivity, the temperature of the thermal element 214 changes if the gas has a thermal conductivity different from that of air even if it is not carbon dioxide gas. The detection accuracy may be reduced. A particularly sensitive gas is water vapor (humidity). Since water vapor also affects the gas sensor, it will be described as a type of gas.

Separating carbon dioxide gas and water vapor and detecting the concentration of carbon dioxide gas with high accuracy can be achieved by detecting the heating temperature of the thermal element 214 at two or more different temperatures. The thermal conductivity of a gas is inherent to the gas, but also varies with temperature. As shown in Table 1, the thermal conductivity of carbon dioxide gas is 0.0386 W / mK at 200 ° C. and 0.0399 W / mK at 300 ° C., but water vapor is 0.0317 W / mK at 200 ° C., 300 0.399 W / mK at ° C. Accordingly, the carbon dioxide gas concentration sensitivity at1 and the water vapor concentration sensitivity bt1 at 200 ° C., the carbon dioxide gas concentration sensitivity at2 and the water vapor concentration sensitivity bt2 at 300 ° C. are obtained in advance, and the carbon dioxide gas concentration sensitivity at 1 and the water vapor concentration sensitivity bt2 are obtained from the simultaneous equations of Equations 1 and 2. The carbon gas concentration X and the water vapor concentration Y can be calculated.
at1X + bt1Y = Vdt1 (Formula 1)
at2X + bt2Y = Vdt2 (Formula 2)
Vdt1 is a signal output of the gas sensor at 200 ° C., and Vdt2 is a signal output of the gas sensor at 300 ° C.

  Next, the operation of the catalytic combustion type gas sensor will be described. The second gas sensor 102 is a contact combustion type gas sensor that detects carbon monoxide, and detects the concentration of the carbon monoxide gas using the combustion heat of the gas. When the carbon monoxide gas burns in the catalyst 215 heated by the heater 211 and the concentration of the carbon monoxide gas increases, the temperature of the thermal element 213 also increases. When the thermal element 213 is an NTC thermistor having a negative temperature coefficient, the thermistor resistance value decreases, and this is input to the control processing circuit 103 as an electric signal to calculate the concentration. Similar to the first gas sensor 101, the thermal element 213 is connected in series with a load resistor (not shown), and uses the voltage at the connection point with the load resistor as an electrical signal. The load resistance may be formed on the gas sensor substrate or may be formed on the control processing circuit 103.

  FIG. 4 is a graph showing the relationship between the gas concentration that changes due to a building fire and time. During the initial fire, the concentrations of carbon monoxide gas 404 and carbon dioxide gas 402 increase, and the concentrations of oxygen 403 and nitrogen decrease. In the fire detection device 100 according to the first embodiment of the present invention, the increase in the concentration of the carbon monoxide gas 404 and the carbon dioxide gas 402 at the time of this initial fire is detected, and a fire state is determined by performing arithmetic processing. be able to.

  With reference to FIGS. 1 and 2, the operation of the fire detection device will be described. The carbon dioxide gas that is the first fire change gas G1 and the carbon monoxide gas that is the second fire change gas G2 due to a fire pass through the vent hole 201 of the package 202 and the heat conduction gas sensor that is the first gas sensor 101. And reaches the catalytic combustion type gas sensor which is the second gas sensor 102. The microheater 211 is controlled to a high temperature by a signal from the control processing circuit 103 and heats the thermal element 214. The signal outputs (VO1, VO2) of the first gas sensor 101 and the second gas sensor corresponding to the concentration increase of each gas are input to the control processing circuit 103 to perform concentration calculation. The concentration calculation is performed in consideration of temperature information from a temperature sensor (not shown). The temperature sensor may be mounted on the control processing circuit. The concentration calculation is intermittently calculated by the control processing circuit 103, and when the concentration of carbon dioxide gas and the concentration of carbon monoxide gas are equal to or higher than a predetermined concentration threshold value and both rise, it is determined as a fire state, and control is performed. The output signal VO5 of the processing circuit 103 is input to an alarm means (not shown), and an alarm is given by voice, buzzer sound, lamp, or the like. Since the fire state is determined using only the gas, it is possible to detect a fire at an early stage. Further, since the fire state is determined from the concentrations of the two kinds of gases, malfunctions can be prevented.

  Hereinafter, Example 1 and Comparative Example 1 specifically show that the present embodiment can determine a fire state early and without malfunction. However, the present invention is not limited to these. FIG. 5 is a graph showing the relationship between alarm time due to smoke and heat (temperature) generated during a fire and alarm time due to carbon monoxide gas.

In Example 1, the fire detection apparatus 100 according to the first embodiment described above was used. In Comparative Example 1, the fire alarm device 600 shown in FIG. 6 was used. FIG. 6 is a schematic configuration diagram illustrating a fire alarm device according to Comparative Example 1.
First, the configuration of the fire alarm device 600 according to Comparative Example 1 will be described. As shown in FIG. 6, the fire alarm device 600 outputs a signal according to a fire sensor 601 that outputs a signal according to heat (temperature) generated by a fire, and a carbon monoxide gas concentration generated by the fire. The gas sensor 602 includes a determination unit 603 that determines a fire based on a signal output from the fire sensor and the gas sensor, and an alarm unit 604 that issues an alarm based on the result of the determination unit.

  In the judging means, four threshold temperatures of 40 ° C., 50 ° C., 55 ° C. and 65 ° C. are set according to the signal output of the fire sensor, and three threshold monoxides of 100 ppm, 200 ppm and 550 ppm are set according to the signal output of the gas sensor. Sort by combination with carbon concentration. The fire condition is when the temperature is 65 ° C. or higher, and the fire confirmation necessary condition is that the temperature is 40 ° C. or higher and the concentration of carbon monoxide gas is 550 ppm, or the temperature is 50 ° C. or higher and the concentration of carbon monoxide gas is 200 ppm or higher. Alternatively, it is determined when the temperature is 55 ° C. or higher and the concentration of carbon monoxide gas is 100 ppm or higher.

  Next, with reference to FIG. 5, fire state determination or alarm time of the fire detection device 100 of the first embodiment and the fire alarm device 600 of the first comparative example will be shown. The horizontal axis in FIG. 5 represents the time since the occurrence of the fire, and the vertical axis represents the smoke concentration, heat (temperature), and carbon monoxide concentration that change as a result of the fire.

  A curve 503 is a change in heat (temperature) that rises due to a fire, and a fire state is determined at the time of the intersection C with the threshold value 504. A curve 502 is a change in the concentration of smoke generated by a fire, and a fire state is determined at the time of the intersection B with the threshold value 504. A curve 501 is a change in the concentration of carbon monoxide gas generated by a fire, and a fire state is determined at the time of the intersection A with the threshold 504. In the case of Comparative Example 1, the gas sensor detects the change in the concentration of carbon monoxide gas, but the fire sensor determines the fire status based only on heat (temperature). Can not. Even if it is determined by a combination with a gas sensor, as long as the temperature change is used by the fire sensor as a fire condition determination, the fire detection time is governed by the fire sensor determination time, and the fire detection is delayed.

  In the case of Example 1, the concentration of carbon dioxide gas when the concentration of carbon monoxide gas is 300 ppm and the concentration of carbon dioxide gas when the concentration of carbon monoxide gas is 500 ppm are detected. When the rate of increase is substantially equal to the rate of increase in the concentration of carbon dioxide gas, a fire condition is determined.

  An example of a smokeless fire will be described as an example. When the concentration of carbon monoxide gas is 300 ppm, the concentration of carbon dioxide gas is 1500 ppm, and when the concentration of carbon monoxide gas is 500 ppm, the concentration of carbon dioxide gas is 2400 ppm. The increase rate of the concentration of carbon monoxide gas is about 1.7 from 500 ppm / 300 ppm. On the other hand, the rate of increase in the concentration of carbon dioxide gas was about 1.8 from (2400-400) ppm / (1500-400) ppm. Therefore, it can be determined that the concentration increase rates of these two gases are substantially equal (1.7≈1.8), and it can be determined that there is a fire condition. Since the concentration of carbon dioxide gas is about 400 ppm even in the air, 400 ppm is subtracted as the offset concentration of carbon dioxide gas, and the change is calculated. In the case of the normal concentration of carbon monoxide gas in the air, the concentration is 0.09 ppm. Therefore, there is no problem even if the increase rate of the concentration of carbon monoxide gas is obtained ignoring the offset concentration of carbon monoxide gas.

  This will be described with reference to FIG. A curve 501 representing the temporal change in the concentration of carbon monoxide gas at the time of the initial fire is substantially overlapped with a curve (not shown) representing the temporal change in the concentration of carbon dioxide gas, although the absolute value of the concentration is different. In other words, if you observe the rate of increase, they are almost equal. The threshold value 505 means 300 ppm in the concentration of carbon monoxide gas, and (1600-400) ppm in the concentration of carbon dioxide gas. Intersection D means the intersection of the curve representing the concentration of carbon monoxide gas and the carbon dioxide concentration threshold, and the intersection of the curve representing the concentration of carbon dioxide gas and the carbon dioxide concentration threshold With both meanings. The threshold value 504 means 500 ppm in the concentration of carbon monoxide gas, and (2400-400) ppm in the concentration of carbon dioxide gas. Intersection A also means the intersection of the curve representing the concentration of carbon monoxide gas and the carbon monoxide gas concentration threshold, and the meaning of the intersection of the curve representing the concentration of carbon dioxide gas and the concentration threshold of carbon dioxide gas With both meanings. In Example 1, the fire condition could be determined 13 minutes earlier than in Comparative Example 1. In other words, since the time difference between the intersection C and the intersection A is 13 minutes, a fire can be detected early and early escape is possible. Furthermore, since the fire state is determined by two kinds of gases that change in the event of a fire, malfunction prevention is also supported.

  The preferred embodiments of the present invention have been described above. The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. In addition, the constituent elements described include those that can be easily assumed by a party and those that are substantially the same. Furthermore, the constituent elements described can be appropriately combined.

  For example, although two types of gas have been described, three or more types of gas that changes during a fire may be detected. In this case, it is possible to further contribute to prevention of malfunction. Of course, the type of gas is not limited to carbon monoxide and carbon dioxide, but can be composed of two or more types of gases that change during a fire. Although the gas sensor is an integrated type, it has been described with two types of gas detection type gas sensors. Also in this regard, one type of gas detection type gas sensor may be used. As a result, the gas sensor can be miniaturized. Also, a plurality of gas detection type gas sensors may be used. By detecting one type of gas with two or more types of gas detection type gas sensors, the gas selectivity may be further improved, and the accuracy of the gas concentration may be improved.

  As described above, the fire detection device 100 according to the present embodiment uses a gas sensor that detects a gas that changes at the time of a fire without using a fire sensor that detects heat or smoke whose fire state is determined slowly. Can detect fire early. Furthermore, when the rate of increase in the concentration of the two types of gas is substantially equal, it is determined that the fire is in the fire state, so that malfunction prevention is also supported.

  The fire detection device according to the present invention can be used for a fire alarm or the like.

  DESCRIPTION OF SYMBOLS 100 ... Fire detection apparatus, 101 ... Gas sensor 1, 102 ... Gas sensor 2, 103 ... Control processing circuit, 200 ... Sectional drawing of a fire detection apparatus, 201 ... Vent, 202 ... Package, 203 ... Package electrode, 204 ... Package electrode penetration Holes 205... Package internal electrodes 206. Metal bumps 207 Bonding wires 208. Insulating layers 209 Control processing circuits 210 Gas sensor substrates 211 Micro heaters 212 Cavities 213 Thermal elements 214 Insulating layer, 215 ... Catalyst, 216 ... Gas sensor electrode, 217 ... Gas sensor 2, 218 ... Gas sensor 1, 301 ... Storage means, 302 ... Gas concentration calculation means, 303 ... Heating means, 304 ... Judgment means, 401 ... Nitrogen gas concentration 402 ... carbon dioxide gas concentration, 403 ... oxygen gas concentration, 40 ... carbon monoxide gas concentration, 501 ... carbon monoxide gas concentration, 502 ... smoke concentration, 503 ... heat (temperature), 504 ... threshold value 1, 505 ... threshold value 2, A ... carbon monoxide gas alarm concentration point 1, B ... Smoke alarm concentration point, C ... thermal alarm temperature point, D ... carbon monoxide gas alarm concentration point 2, 600 ... fire alarm device, 601 ... fire sensor, 602 ... gas sensor, 603 ... determination means, 604 ... alarm means

Claims (6)

One or more gas sensors that detect at least two types of gas that change in the event of a fire, and a control processing circuit that controls the gas sensors and processes output signals from the gas sensors;
The fire detection apparatus, wherein the control processing circuit includes a determination unit that determines a fire from a concentration change of the at least two kinds of gases.   The gas sensor includes one or more gas sensors that detect carbon monoxide gas and carbon dioxide gas, and the determination means determines whether the carbon monoxide gas concentration increase rate and the carbon dioxide gas concentration increase rate cause a fire. The fire detection device according to claim 1, wherein the determination is performed.   The fire detection device according to claim 2, wherein the determination unit determines that a fire occurs when the concentration increase rate of the carbon monoxide gas and the concentration increase rate of the carbon dioxide gas are substantially equal.   The fire detection device according to any one of claims 1 to 3, wherein the gas sensor includes a heat conduction type gas sensor that detects carbon dioxide gas.   The control processing circuit has heating means for heating the thermosensitive element of the gas sensor at at least two different temperatures, and storage means for storing gas concentration sensitivity corresponding to the temperature, and the output signal of the gas sensor and the gas concentration The fire detection device according to claim 4, further comprising gas concentration calculation means for calculating a gas concentration from sensitivity. The fire detection device according to any one of claims 1 to 5, wherein the gas sensor and the control processing circuit are housed in one package.

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