JP4704591B2 - Fire detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fire detection device that detects a fire, and particularly to a fire detection device that detects a fire using a humidity sensor or a catalytic combustion gas sensor as a detection element.
[0002]
[Prior art]
Conventionally, this type of fire detection device detects a fire by temperature detection or smoke detection. However, in conventional fire detection devices, alarms often did not fire at the beginning of the fire. This problem will be described below with reference to FIG.
[0003]
First, this type of conventional fire detection device will be briefly described. There are basically two types of conventional fire detection devices. The first is a heat-sensing fire detection device, which uses a temperature sensor, thermistor, bimetal, etc. to detect temperature changes in the room that rise due to the heat at the time of the fire. Fire detectors and actuated fire detectors are known. The constant-temperature fire detection device issues a fire alarm when, for example, the room reaches a reference temperature that cannot be normal, such as 60 ° C. or 70 ° C. Further, the actuating fire detection device issues a fire alarm when the rate of temperature increase per unit time reaches an unusable level, for example, 15 ° C./min.
The second is a smoke-sensing fire detection device. This fire detection device detects photoelectric changes using light scattering and changes in the ionic current in the air to detect smoke in the event of a fire. There is an ionization type that issues a fire alarm.
[0004]
By the way, there is a well-known European standard as a standard indicating the degree of fire. This standard will be used to explain the early stage fire. FIG. 14A is an explanatory diagram showing the types of test fires defined by the European Standard (EN54: Part9), and FIG. 14B is an explanatory diagram showing classification according to the degree of fire and its reference value. FIG. 14 (C) is an explanatory diagram showing parameters indicating significant changes for each test fire of FIG. 14 (A).
[0005]
For example, the fire test TF4 shown in FIG. 14A will be described as an example. In this test, in a fire test chamber (6 × 10 × 4 m), three polyurethanes (50 × 50 × 2 cm) are placed at 5 cm.^ThreeA fire is artificially ignited using methyl alcohol as a combustion aid. As time elapses from ignition, fire classes progress in the order of classes A, B, C, and N shown in FIG. In this classification, as shown in FIG. 14C, in the case of TF4, the degree of ionization and the optical smoke density determination are adopted as parameters indicating significant changes, and the measured values corresponding to these parameters are shown in FIG. It is performed by comparing with the reference value shown in 14 (B). In the case of fire test TF5, in a fire test room (6 × 10 × 4 m), 650 g of heptane placed in an iron can (33 × 33 × 5 cm) is ignited to cause a fire. The fire classification is the same as described in the fire test TF4. The other fire tests TF1, 2, 3 and 6 are also tested in the same test chamber using different combustion materials. The initial fire corresponds to the vicinity of the class BC boundary in the above unified standard.
[0006]
[Problems to be solved by the invention]
However, in the vicinity of the class BC boundary corresponding to the above-mentioned initial fire, the parameter value can occur even in a daily state other than a fire as shown in FIG. Therefore, in the conventional fire detection device, in the case of the heat detection type, for example, the reference temperature is set to 70 ° C., and the reference temperature change rate is set to 15 ° C./min. Also in the smoke detection type, in order to prevent false alarms due to cigarette smoke, the conventional fire detection device sets the reference smoke density level to be higher than the class BC boundary. For this reason, it has been difficult for a conventional fire detection device to detect such an early stage fire.
[0007]
Therefore, in view of the above-described present situation, the present invention has an object to provide a fire detection device that accurately detects a fire at an early stage by paying attention to a peculiar humidity change pattern at the initial stage of a fire. Another object of the present invention is to provide a fire detection device that accurately detects a fire at an early stage by paying attention to a unique sensor output change pattern in the early stage of fire obtained from the sensor output of a catalytic combustion type gas sensor. .
[0012]
  Claims made to solve the above problems1As shown in FIG. 5, the described fire detection device is a fire detection device that detects a fire based on a sensor output from a gas sensor provided in a gas leak alarm, and the gas sensor is heated by energization. It is a catalytic combustion type gas sensor 40 to be driven, and from the sensor output time series data obtained from the sensor output at a specific point in the rising period until the sensor output after being energized is stabilized, The fire is detected by detecting a sensor output change pattern.
[0013]
  Claim1According to the described invention, the catalytic combustion type gas sensor 40 provided in the gas leak alarm is used as the fire detection element. This catalytic combustion type gas sensor 40 is heated and driven by energization. From the sensor output time series data obtained from the sensor output at a specific time during the rising period until the sensor output after energization becomes stable, A fire is detected by detecting a unique sensor output change pattern of the sensor output. That is, the contact combustion type gas sensor 40 has a response characteristic with respect to humidity and smoke concentration as shown in FIGS. 9 and 12 at a specific time point during the rising period until the sensor output after being energized is stabilized. In the initial stage of fire, changes in humidity and smoke concentration are particularly significant. Therefore, the catalytic combustion type gas sensor 40 exhibits a unique sensor output change pattern as shown in FIGS. 10 and 11, which is used for fire detection. The Therefore, the claims1In the described invention, the initial fire, which is difficult to detect with the conventional fire detection device, is reliably detected by using the sensor output of the catalytic combustion type gas sensor 40.
[0014]
  Claims made to solve the above problems2The fire detection device described is claimed as shown in FIG.1In the fire detection device described above, the specific change pattern is the sensor output that rises after a temporary drop that is peculiar to the initial stage of a fire.
[0015]
  Claim2According to the described invention, since the characteristic sensor output change pattern is a characteristic sensor output that rises and then rises, which is peculiar to the initial stage of fire, as shown in FIGS. It becomes possible to detect a fire with a certainty at an early stage. That is, at the beginning of the fire, the sensor output rises after temporarily falling due to the characteristic humidity rise and fall and a sudden smoke concentration rise.2In the described invention, by detecting this, a fire accompanied by flame and smoke is detected at an early stage.
[0016]
  Claims made to solve the above problems3The fire detection device described is claimed as shown in FIG.2In the fire detection device described above, sensor driving means 101 for driving the catalytic combustion gas sensor 40 at predetermined intervals, sensor output acquisition means 102 for acquiring the sensor outputs at a plurality of the specific time points, and the acquired plurality Sensor output time series data generating means 103 for generating the sensor output time series data, sensor output change pattern storage means 104 for storing the sensor output change pattern in advance, the sensor output time series data and the sensor output Based on the comparison result with the sensor output change pattern, the comparison detection means 105 for detecting the fire, and the alarm instruction means 106 for instructing the fire alarm section for issuing a fire alarm to alarm the detected fire. It is characterized by including.
[0017]
  Claim3According to the described invention, the sensor drive means 101, the sensor output acquisition means 102, the sensor output time series data generation means 103, the sensor output change pattern storage means 104, the comparison detection means 105, and the alarm command means 106 are included. In such a configuration, the catalytic combustion gas sensor 40 is driven at a predetermined interval by the sensor driving means 101, and the sensor output time-series data generating means 103 outputs the sensor output time based on the sensor output acquired by the sensor output acquiring means 102. Series data is generated, and this sensor output time series data is compared with the above-mentioned unique sensor output change pattern stored in advance in the sensor output change pattern storage unit 104 by the comparison detection unit 105. Then, based on the comparison result, the alarm command means 106 is instructed to warn of a fire.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
Reference example
  First, the present invention will be described with reference to FIGS.Reference exampleWill be described. FIG. 1 shows a fire detection device according to the present invention.Reference exampleIt is a block diagram which shows the basic composition of. As shown in FIG. 1, the controller 10 includes a humidity sensor.2And the fire alarm unit 3 is connected. This fire detection device detects a fire based on the atmospheric humidity detected by the humidity sensor 2. This principle will become clear from the description with reference to FIGS.
[0020]
The humidity sensor 2 is a humidity sensor element that detects humidity in the atmosphere. The humidity sensor 2 may be a known humidity sensor element, and may not be a normal humidity sensor element as long as it is an element that outputs a detection signal according to humidity. The fire alarm unit 3 is instructed by the controller 10 and issues a fire alarm by voice, light emission display, or the like, and includes a known speaker, LED, and their driver circuits.
[0021]
The controller 10 has a function of detecting a fire at an initial stage by detecting a specific humidity change pattern in which the humidity supplied from the humidity sensor 2 temporarily rises and then falls in the early stage of the fire. This specific humidity change pattern will be described later with reference to FIGS. The controller 10 includes a humidity time series data generation unit 11, a humidity change pattern storage unit 12, a comparison detection unit 13, and an alarm command unit 14. The controller 10 includes a calculation unit, a storage unit, a timer unit, and the like as hardware. This corresponds to the processing operation.
[0022]
The humidity time series data generation unit 11 generates humidity time series data from the humidity detected by the humidity sensor 2. This humidity time series data is used when compared with a humidity change pattern stored in advance in the humidity change pattern storage means 12 in order to detect a fire. The comparison detection means 13 compares the humidity time series data with the humidity change pattern, and detects a fire based on the comparison result. Then, the alarm command means 14 instructs the fire alarm unit 3 that issues a fire alarm by voice or the like to warn the detected fire. The humidity change pattern storage unit 12 is included in a storage unit included in the controller 10.
[0023]
The controller 10 includes a gas sensor 4 for detecting CO gas at the time of gas leakage, a speaker and an LED for issuing an alarm by sound, light emission display, and the like, and a gas leakage alarm unit 5 including their driver circuits. The fire detection device may have a function of detecting gas leakage. In this case, the controller 10 receives the detection output from the gas sensor 4 and compares it with a reference value for determining gas leakage. A gas leak is warned by a luminescent display. Thereby, this fire detection apparatus comes to be able to detect a gas leak and a fire with one unit.
[0024]
  Here, FIG. 2 and FIG.Reference exampleThe principle of fire detection in will be described. FIG. 2 is a graph showing the relationship between the elapsed time and the humidity change collected based on the fire test TF4 shown in FIG. FIG. 3 is a graph showing the relationship between elapsed time and humidity change collected based on the fire test TF5 shown in FIG.
[0025]
FIG. 2 assumes a plastic fire. In FIG. 2, T1 is the fuel injection time, Ts is the ignition time, Tab is the class AB boundary passage time, Tbc is the class BC boundary passage time, and Te is the end time. As shown in this figure, after ignition at the ignition time Ts (600 s), the initial relative humidity of 48% gradually increases, reaches 55% at 820 s and reaches its peak. It continues to decrease rapidly until the end time Ts. The time point of the peak reaching 55% is immediately after the class BC boundary passage time Tbc, which is the initial stage of the fire.
The reason is as follows. That is, immediately after the ignition time Ts, moisture (water vapor) is remarkably generated by the combustion of the material, so that the relative humidity temporarily increases as shown by the solid line in FIG. However, as the temperature rises with time as shown by the dotted line in FIG. 2, the saturated water vapor pressure also increases with this, so the relative humidity decreases conversely in the vicinity of the class BC boundary passage time Tbc. Turn to. As described above, since the relative humidity reaches a peak immediately after the class BC boundary passage time Tbc, which is the initial stage of the fire, it is possible to detect the fire at the initial stage using this phenomenon.
[0026]
FIG. 3 assumes a liquid fuel fire. In FIG. 3, T1 is the fuel injection time, Ts is the ignition time, Tab is the class AB boundary passage time, Tbc is the class BC boundary passage time, Tcn is the class CN boundary passage time, and Te is finished. Indicates the time. Again, after ignition at the ignition time Ts (530s), the initial relative humidity of 43% gradually increases, reaches 51% at the time of 610s and reaches a peak, and then reaches the end time Ts. It keeps decreasing rapidly. The peak point reaching 51% is again immediately after the class BC boundary passing point Tbc, which is the initial stage of the fire. The reason for this is that, as described in FIG. 2 above, the relative humidity is temporarily increased due to significant water vapor generation immediately after the ignition time Ts shown by the solid line in FIG. 3, and the temperature rises with the passage of time shown by the dotted line in FIG. The relative humidity due to the increase in saturated water vapor pressure due to is due to the decrease.
[0027]
For the reasons described above, in the flammable combustion fire, the humidity changes as shown in the tests TF4 and TF5, and by using this humidity change pattern, the fire can be detected in the initial stage.
[0028]
  According to the present invention, fire detection is performed using the humidity change pattern as described above.Reference exampleThe processing operation related to will be described with reference to FIG. FIG. 4 illustrates the present invention.Reference exampleIt is a flowchart which shows the processing operation in connection with.
[0029]
  thisReference exampleIn the embodiment, the fire is detected by detecting and sampling the humidity every 10 seconds and detecting the characteristic humidity change pattern at the initial stage of the fire as described in FIGS. 2 and 3. The specific humidity change pattern that temporarily rises and then falls as the fire detection reference is stored in advance in the humidity change pattern storage means 12 included in the controller 10 shown in FIG.
[0030]
  In step S1 of FIG. 4, the timing for detecting humidity is on standby. That is, since the humidity is detected every 10 seconds as described above, the timing at which 10 seconds elapse from the previous humidity detection time is awaited (N in step S1). If it is determined that 10 seconds have passed since the previous humidity detection time, the process proceeds to step S2 to newly detect the humidity (Y in step S1). However, at the start of detection immediately after the switch is turned on, the process proceeds to step S2 without waiting for 10 seconds.
  In step S2, the humidity detected by the humidity sensor 2 is temporarily held in the storage unit of the controller 10, and the process proceeds to step S3. In step S3, the humidity data held in the storage unit is read to generate humidity time series data. This humidity time-series data is sampling data suitable for detecting the specific humidity change pattern, for example, for 50 seconds (5 times). Therefore, at least the past five humidity sampling data are held in the storage unit..
[0031]
  Next, in step S4, the generated humidity time series data is compared with a humidity change pattern stored in advance in the humidity change pattern storage means 12, and a humidity change pattern is detected. Here, if the humidity change pattern is detected, it is determined that an initial fire has been detected, and the process proceeds to step S5 to issue a fire alarm (Y in step S4). Otherwise, the step is performed to continue humidity detection. Return to S1 (N in Step S4).
  In step S5, the fire alarm unit 3 is commanded, a fire is alarmed from the time of voice and display, and a series of processing ends..
[0032]
  As described above, the present inventionReference exampleAccording to the above, the fire is detected by detecting a specific humidity change pattern in which the humidity temporarily rises and then falls in the initial stage of the fire, so that the fire can be reliably detected at the initial stage. become. That is, as shown in FIGS. 2 and 3, the humidity has a characteristic humidity change pattern in which the humidity temporarily rises and then falls in the vicinity of the class BC boundary corresponding to the initial fire. Thus, it is possible to reliably detect an initial fire that has been difficult to detect with conventional fire detection devices. Further, by causing the controller 10 to perform the processing operation as shown in FIG. 4, a realistic fire detection device can be obtained.
[0033]
Embodiment
  Furthermore, using FIG. 5 to FIG.EmbodimentWill be described.
  thisEmbodimentFirst, this will be described with reference to FIGS.EmbodimentThe basic configuration and the drive waveform will be described. Next, using FIG.EmbodimentThe structure of the catalytic combustion type gas sensor 40 used in FIG. Next, with reference to FIGS.EmbodimentThe principle of fire detection in will be described. And this using FIG.EmbodimentThe processing operation related to will be described.
[0034]
  First, using FIG. 5 and FIG.EmbodimentThe basic configuration and the drive waveform will be described. FIG. 5 shows the fire detection device of the present invention.EmbodimentIt is a block diagram which shows the basic composition of. 6 is similar to FIG.EmbodimentIt is a time chart which shows the example of the drive waveform used for.
[0035]
As shown in FIG. 5, the controller 100 is connected to a catalytic combustion type gas sensor 40 including a detection bridge circuit, a fire alarm unit 3, a gas leak alarm unit 5, and a drive power source 6. In this fire detection device, a drive waveform as shown in FIG. 6 is supplied, the energization control of the catalytic combustion type gas sensor 40 is performed, and a fire is detected based on the sensor output of the sensor 40. This principle will become apparent from the description with reference to FIGS.
[0036]
The catalytic combustion gas sensor 40 is heated and driven by energization, and a drive waveform as shown in FIG. 6 is supplied to control this energization. As shown in FIG. 6, the drive waveform is a pulse signal that repeats ON for 0.2 seconds and OFF for 9.8 seconds at a predetermined interval (for example, every 10 seconds). In FIG. 6, Ton and Toff indicate the ON time point and the OFF time point, respectively. The detection time Tvs is set 0.02 seconds after the ON time Ton. This detection time Tvs is a timing at which a sensor output is acquired when a fire is detected using the catalytic combustion type gas sensor 40, and this is a specific time during a rising period until the sensor output after energization is stabilized. This detection time Tvs will be described later.
[0037]
The catalytic combustion gas sensor 40 basically includes a sensitive element portion Rs and a compensation element portion Rr. The sensitive element portion Rs is (platinum) Pt heater 42 and Pd / Al.₂O_ThreeIt includes a catalyst layer 43, and the compensation element portion Rr includes a Pt heater 44 and (alumina) Al₂O_ThreeA catalyst layer 45 is included. The Pt heater 42 and the Pt heater 44 constitute a bridge circuit together with the fixed resistors R1 and R2 and the variable resistor Rv. Driving power is intermittently supplied at predetermined intervals to the connection point between the Pt heater 44 and the fixed resistor R1 and the connection point between the Pt heater 42 and the fixed resistor R2 of the bridge circuit via the controller 100. . A voltage value as a sensor output is supplied to the controller 100 from the connection point of the Pt heaters 42 and 44 and the variable resistor Rv.
[0038]
When using the catalytic combustion gas sensor 40, first, the variable resistance Rv is adjusted so that the voltage value indicating the sensor output becomes zero in the initial state. In this state, when CO gas or the like touches the sensitive element portion Rs, the surface of the element is oxidized by the catalytic action, and reaction heat is generated. Due to this reaction heat, the resistance value of the Pt heater 42 rises, and this rise in resistance value breaks the balance of the bridge circuit, and the sensor output is supplied to the controller 100. In this case, the Pt heater 44 compensates for the fluctuation of the resistance value of the Pt heater 42 due to the fluctuation of the ambient temperature so that only the fluctuation component of the resistance value of the Pt heater 42 caused by the reaction heat can be extracted. The structure of the catalytic combustion gas sensor 40 will be described later with reference to FIG.
[0039]
The controller 100 detects, from the sensor output time-series data obtained from a plurality of sensor outputs at the detection time Tvs, a unique sensor output change pattern of the sensor output at the initial stage of the fire, that is, a pattern that rises after being temporarily lowered It has a function to detect fire by doing. This sensor output change pattern will be described later with reference to FIGS. The controller 100 includes a sensor driving unit 101, a sensor output acquisition unit 102, a sensor output time series data generation unit 103, a sensor output change pattern storage unit 104, a comparison detection unit 105, and an alarm command unit 106. The controller 100 includes a calculation unit, a storage unit, a timer unit, and the like as hardware. Each of the units 101 to 103, 105, and 106 is a diagram that will be described later performed by the calculation unit according to a control program stored in the storage unit. This corresponds to 13 processing operations.
[0040]
The sensor driving means 101 controls the energization of the drive power source 6 such as a battery to the catalytic combustion gas sensor 40 to drive the catalytic combustion gas sensor 40 at a predetermined interval. The sensor output acquisition unit 102 acquires sensor outputs at a plurality of the detection times Tvs in the interval, that is, 10 seconds. The sensor output time series data generation unit 103 generates sensor output time series data from the plurality of sensor outputs acquired by the sensor output acquisition unit 102. This sensor output time series data is used when compared with a sensor output change pattern stored in advance in the sensor output change pattern storage means 104 in order to detect a fire. The comparison detection unit 105 detects a fire based on the comparison result between the sensor output time series data and the sensor output change pattern. Then, the alarm command means 14 instructs the fire alarm unit 3 that issues a fire alarm by voice or the like to warn the detected fire. It is assumed that the sensor output change pattern storage unit 104 is included in a storage unit included in the controller 100.
[0041]
  The fire alarm unit 3 and the gas leak alarm unit 5 are shown in FIG.Reference exampleIn the same manner as described above, a fire alarm or a gas leak alarm is constituted by a known speaker or LED that emits a sound or a light emission display or the like, and a driver circuit thereof.
[0042]
The controller 100 is connected to a gas leak alarm unit 5 composed of a speaker or LED and a driver circuit for emitting a gas leak alarm by sound or light emission display, etc. You may give the function of. In this case, the controller 100 receives the detection output from the catalytic combustion type gas sensor 40, compares this with the gas leak reference value, determines the gas leak, and instructs the gas leak alarm unit 5 by voice or light emission display. Control to warn of gas leak. Thereby, this fire detection apparatus comes to be able to detect a gas leak and a fire with one unit.
[0043]
  Next, using FIG.EmbodimentThe structure of the catalytic combustion type gas sensor 40 used in FIG. 7A, 7B, and 7C are a plan view, a rear view, and a cross-sectional view taken along line AA of the catalytic combustion type gas sensor, respectively.
[0044]
As shown in FIGS. 7A and 7B, the catalytic combustion type gas sensor is formed on (silicon) Si wafer 41 on (oxidized) SiO 2.₂Film 48c, (nitrided) SiN film 48b, and (hafnium oxide) HfO₂An insulating thin film made of the film 48a is formed as a raw film, on which a (platinum) Pt heater 42 and a Pd / Al as the sensitive element portion Rs are formed.₂O_Three(Platinum) Pt heater 44 and (Alumina) Al as catalyst layer 43 and compensation element Rr₂O_ThreeA catalyst layer 45 is formed. Also, as shown in FIG. 7C, the concave portions 46 and 47 are formed by anisotropic etching, and the thin film diaphragms Ds and Dr are formed, respectively, to reduce the heat capacity. With such a configuration, a contact combustion type gas sensor capable of high-speed reaction can be obtained.
[0045]
  Next, with reference to FIGS.EmbodimentThe principle of fire detection in will be described. First, it will be described with reference to FIGS. 8 and 9 that the catalytic combustion gas sensor 40 has responsiveness not only to combustible gas but also to humidity. 10 and 11 show that the catalytic combustion type gas sensor 40 has a unique sensor output change pattern in the initial stage of the fire. Further, FIG. 10 to FIG. While explaining the factors, it will be explained that the sensor output of the catalytic combustion gas sensor 40 can be used for fire detection.
[0046]
FIG. 8 is a graph showing the combustible gas characteristics of the contact combustion type gas sensor 40, that is, the sensor output output characteristics of each combustible gas with respect to the elapsed time from the pulse ON time. FIG. 9 is a graph showing the humidity characteristics of the catalytic combustion type gas sensor 40, that is, the sensor output output characteristics at each humidity with respect to the elapsed time from the pulse ON time.
[0047]
8 and 9, the horizontal axis indicates the time from the pulse ON time (time 0 in FIGS. 8 and 9) when the driving pulse as shown in FIG. 6 is supplied to the contact combustion gas sensor 40. Indicates elapsed time. However, in FIG. 8 and FIG. 9, the sensor output is collected with the pulse ON period set to 200 ms or more.
[0048]
In FIG. 8, Sv1 represents the sensor output characteristic of (carbon monoxide) CO gas, and similarly, Sv2, Sv3, and Sv4 represent (methane) CH_FourGas, (hydrogen) H₂Gas, (isobutane) C_FourH_TenThe sensor output characteristic of gas is shown. These gases are generated at the time of gas leakage. Here, the concentration of each gas was 3000 ppm and data was collected. As shown in FIG. 8, the catalytic combustion gas sensor 40 has a unique sensor output waveform for each gas. In particular, the sensor output for the four types of gases rises with a unique waveform until 100 ms elapses from the time point 0 (pulse ON time), but after 100 ms, the steady state of the specific output value is found. Utilizing such characteristics, the catalytic combustion gas sensor 40 can detect a gas leak.
[0049]
Moreover, as shown in FIG. 9, this contact combustion type gas sensor 40 also has a humidity characteristic. In FIG. 9, RH30 indicates a sensor output characteristic at a relative humidity of 30%, and similarly RH50 and RH70 indicate a sensor output characteristic at a relative humidity of 50% and 70%, respectively. Here, humidity data at room temperature (25 ° C.) was collected. As shown in FIG. 9, the contact combustion type gas sensor 40 has a unique sensor output waveform for each humidity. In particular, it can be seen that the sensor output rises while drawing a waveform peculiar to each humidity until 100 ms elapses from the time 0 (pulse ON time), and after 100 ms, each humidity is in a steady state at the same sensor output value. Thus, the humidity characteristic of the sensor output until 100 ms elapses from time 0 can also be used for fire detection described later.
[0050]
FIG. 10 is a graph showing the relationship between elapsed time and sensor output taken based on the fire test TF4. FIG. 11 is a graph showing the relationship of elapsed time-sensor output collected based on the fire test TF5. FIG. 12 is a graph showing the relationship between smoke density and sensor output.
[0051]
10 and 11, the relationship between elapsed time and smoke density is also shown for reference. In FIGS. 10 and 11, for example, using the drive pulse as described in FIG. 6, the sensor output is output at intervals of 10 seconds with the detection time Tvs being 0.02 seconds after the pulse ON time Ton. Collected. In addition, the test environments of the fire tests TF4 and TF5 are performed by slightly downscaling the test environment defined by the above-mentioned European standard. FIG. 12 shows that the smoke density and the sensor output have a substantially proportional relationship, and the detection is 0.02 seconds after the pulse ON time indicated by Ss1 rather than 0.2 seconds after the pulse ON time indicated by Ss2. The point in time indicates that the proportional relationship is established more remarkably.
[0052]
In the fire test TF4 shown in FIG. 10, the sensor output Sv rapidly decreases from 0V at the ignition time Ts, and becomes −0.4V after 20 to 30 seconds, and increases rapidly with this point as the minimum value. Begin to. Thereafter, the sensor output Sv varies between 0 and 0.3 V with time, and does not exhibit a remarkable variation characteristic. That is, it can be considered that one of the reasons that the sensor output becomes the minimum immediately after the ignition time Ts is caused by the humidity fluctuation. As described with reference to FIG. 2, it was found that the relative humidity temporarily increased due to significant water vapor generation immediately after the ignition time Ts, and then turned to decrease due to an increase in saturated water vapor pressure due to a temperature rise with time. Further, as described with reference to FIG. 9, it was found that the sensor output decreases as the relative humidity increases. Therefore, the sensor output minimum peak immediately after the ignition time Ts in FIG. 10 can be considered to be caused by a characteristic humidity change in the early stage of fire.
[0053]
On the other hand, as shown by the dotted line in FIG. 10, the smoke concentration Ss increases rapidly from 0 V at the ignition time Ts, and after reaching the maximum at 70 μA after 30 to 40 seconds, the smoke concentration Ss decreases slightly from 50 to 50 It turns out that it fluctuates at 70 μA. Also, as indicated by Ss1 in FIG. 12, it can be seen that the sensor output collected when 0.02 seconds have elapsed from the pulse ON time (same timing as the detection time Tvs in FIG. 10) is substantially proportional to the smoke density. That is, another factor of the sensor output minimum peak immediately after the ignition time Ts in FIG. 10 (especially the sensor output that rapidly increases in the positive direction after this minimum peak) is due to a rapid increase in smoke concentration in the early stage of fire. Can be considered.
[0054]
Thus, the sensor output minimum peak immediately after the ignition time Ts can be considered to be caused by a sudden rise in smoke density peculiar to this period in addition to a peculiar humidity change at the beginning of the fire. In other words, by detecting the minimum sensor output peak immediately after the ignition time Ts, it becomes possible to detect a fire accompanied by flame and smoke like the fire test TF4 in the initial stage.
[0055]
The same applies to the fire test TF5 shown in FIG. In FIG. 11, the sensor output Sv rapidly decreases from 0 V at the ignition time Ts, reaches a minimum point at −1.2 V after about 20 seconds, and starts to increase rapidly with this point as the minimum peak. Further, as shown by the dotted line in FIG. 11, the smoke concentration rapidly increases from 0 V at the ignition time Ts, and after reaching the maximum after about 30 seconds, it may vary from 50 to 60 μA. Recognize. In other words, in the fire test TF5, as in the fire test TF4, the sensor output Sv is caused by the rapid increase in the smoke concentration peculiar to this period in addition to the peculiar humidity change at the beginning of the fire. It can be considered that a minimum peak is reached soon after. That is, by detecting the minimum sensor output peak immediately after the ignition time Ts, it becomes possible to detect a fire accompanied by flame and smoke like the fire test TF5 in the initial stage.
[0056]
In this way, by using the sensor output of the catalytic combustion type gas sensor 40 that rises and then rises, which is peculiar to the early stage of fire, it is possible to reliably detect fires with flames and smoke at the initial stage. Become.
[0057]
By utilizing the sensor output characteristics of the catalytic combustion type gas sensor 40 as described above, it becomes possible to detect a fire accompanied by flame and smoke at an initial stage. Embodiment which performs a fire detection using the sensor output of such a contact combustion type gas sensor 40 is described using FIG.
[0058]
  FIG. 13 illustrates the present invention.EmbodimentIt is a flowchart which shows the processing operation in connection with. In the embodiment, using the driving pulse as shown in FIG. 6, the sensor output is obtained at intervals of 10 seconds with the detection time Tvs being 0.02 seconds after the pulse ON time Ton, and FIGS. The fire is detected by detecting a unique sensor output change pattern at the initial stage of the fire as described in FIG. The characteristic humidity change pattern that rises after the temporary lowering as described above, which becomes the reference for fire detection, is stored in advance in the sensor output change pattern storage means 104 included in the controller 100 shown in FIG.
[0059]
  In step S101 in FIG. 13, the pulse ON timing (Ton) is on standby. That is, since the pulse OFF period is 9.8 seconds as described above, here, 9.8 seconds have elapsed from the previous time Toff (see FIG. 6), and the timing for turning on the pulse again is awaited ( N of step S101). Then, when 9.8 seconds have elapsed from the previous pulse OFF time Toff, the process proceeds to step S102 in order to issue a new pulse ON command (Y in step S101). However, when detection is started immediately after the switch is turned on, the process proceeds to step S102 without waiting for 9.8 seconds.
  In step S102, a pulse ON is commanded at time Ton (see FIG. 6). Then, when 0.02 seconds elapse from the pulse ON time Ton and the detection time Tvs is reached (see FIG. 6), the sensor output is acquired (Y in Step S103, Step S104). The reason why the detection time Tvs is set to 0.02 seconds after the time Ton is that the humidity and smoke density characteristics are remarkable in the graphs shown in FIGS. 9 and 12, respectively. This detection time Tvs is claimed1, 3It corresponds to a specific point in time. Step S104 corresponds to sensor output acquisition means. The sensor output acquired here is temporarily held in the storage unit of the controller 100, and the process proceeds to step S105.
[0060]
  Then, when 0.2 seconds have elapsed from the time point Ton and the pulse OFF time point Toff is reached (see FIG. 6), the pulse is turned off (Y in step S105, step S106).
  Next, in step S107, sensor output data held in the storage unit is read to generate sensor output time series data. The sensor output time-series data is, for example, sampling data for 50 seconds (5 times) suitable for detecting the above-mentioned unique sensor output change pattern (see FIGS. 10 and 11). Therefore, the storage unit holds at least sampling data of sensor outputs for the past five times. In addition, this step S107 is claimed.3Corresponds to the sensor output time-series data generating means.
[0061]
  In step S108, the generated sensor output time-series data is compared with a sensor output change pattern stored in advance in the sensor output change pattern storage means 104, so that a unique sensor output change pattern in the early stage of fire is detected. Done. Here, when the sensor output change pattern is detected, it is determined that an initial fire has been detected, and the process proceeds to step S109 to issue a fire alarm (Y in step S108). Otherwise, the sensor output is to be continued. The process returns to step S101 (N in step S108). This step S108 is claimed.3It corresponds to the comparison detection means.
  In step S109, the fire alarm unit 3 is commanded, a fire is alarmed from the time of voice and display, and a series of processing ends. This step S109 claims3It corresponds to the alarm command means. In addition, said step S101, step S102, step S105, and step S106 are claims.3This corresponds to the sensor driving means.
[0062]
  As described above, the present inventionEmbodimentAccording to the above, after the sensor output is sampled at a predetermined interval at a specific point in the rising period until the sensor output of the catalytic combustion gas sensor 40 after being energized is stabilized, the sensor output is temporarily lowered during the initial period of fire. Since the sensor output of the rising catalytic combustion type gas sensor 40 is detected, it is possible to reliably detect a fire accompanied by flame and smoke at an initial stage. In addition, since the catalytic combustion type gas sensor 40 originally used for gas leak detection is used as a fire detection element, the man-hour for developing a new fire detection element is reduced, which leads to cost reduction of the apparatus. Furthermore, by causing the controller 100 to perform the processing operation as shown in FIG. 13, a realistic fire detection device can be obtained.
[0063]
The present invention does not limit the specific time point after 0.02 seconds of energization, but may be at any other time point as long as the contact combustion gas sensor 40 has a rising period until the sensor output having humidity characteristics is stabilized. Good. Also, the drive pulse interval and the like can be changed as appropriate. In the present invention, the numerical values employed in the embodiments can be changed as appropriate without departing from the spirit of the invention.
[0066]
【The invention's effect】
  Claim1According to the described invention, by using the sensor output of the catalytic combustion type gas sensor 40 in the rising period after energization, it is possible to reliably detect the initial fire that was difficult to detect with the conventional fire detection device. Become. In addition, since the catalytic combustion type gas sensor 40 used for gas leak detection is used as a fire detection element, man-hours for developing a new fire detection element are reduced, leading to cost reduction of the apparatus.
[0067]
  Claim2According to the described invention, it is possible to reliably detect a fire with flame and smoke at an early stage by using a sensor output that rises after a temporary lowering peculiar to an early stage of fire for fire detection. Become.
[0068]
  Claim3According to the described invention, the above-mentioned sensor driving means 101, sensor output acquisition means 102, sensor output time series data generation means 103, sensor output change pattern storage means 104, comparison detection means 105, and alarm command means 106 are used to cause an initial fire A realistic fire detection device that can reliably detect in stages can be obtained.
[0069]
[Brief description of the drawings]
FIG. 1 shows a fire detection device according to the present invention.Reference exampleIt is a block diagram which shows the basic composition of.
FIG. 2 is a graph showing a relationship between elapsed time and humidity change collected based on a fire test TF4.
FIG. 3 is a graph showing a relationship between elapsed time and humidity change collected based on a fire test TF5.
FIG. 4 of the present inventionReference exampleIt is a flowchart which shows the processing operation in connection with.
FIG. 5 shows a fire detection device according to the present invention.EmbodimentIt is a block diagram which shows the basic composition of.
6 is a diagram of FIG.EmbodimentIt is a time chart which shows the example of the drive waveform used for.
7 (A), (B) and (C) are respectively shown in FIG.EmbodimentIt is the top view, rear view, and AA sectional view taken on the line of the catalytic combustion type gas sensor used in 1).
FIG. 8 is a graph showing combustible gas characteristics of a catalytic combustion type gas sensor.
FIG. 9EmbodimentIt is a graph which shows the humidity characteristic of the contact combustion-type gas sensor used by Fig.2.
FIG. 10 is a graph showing the relationship between elapsed time and sensor output collected based on fire test TF4.
FIG. 11 is a graph showing the relationship between elapsed time and sensor output collected based on fire test TF5.
FIG. 12 is a graph showing the relationship between smoke density and sensor output.
FIG. 13 shows the present invention.EmbodimentIt is a flowchart which shows the processing operation in connection with.
FIG. 14 (A) is an explanatory diagram showing the types of test fires defined in the European standard, and FIG. 14 (B) is an explanatory diagram showing classification according to the degree of fire and its reference value. FIG. 14C is an explanatory diagram showing parameters indicating significant changes with respect to each test fire of FIG.
[Explanation of symbols]
2 Humidity sensor (humidity detection means)
3 Fire alarm
5 Gas leak alarm section
10, 100 controller
40 Contact combustion gas sensor
42, 44 Pt heater
43 Pd / Al₂O_ThreeCatalyst layer
45 Al₂O_ThreeCatalyst layer
Rs sensitive element part
Rr compensation element

Claims (3)

A fire detection device that detects a fire based on a sensor output from a gas sensor equipped in a gas leak alarm,
The gas sensor is a contact combustion type gas sensor that is heated and driven by energization,
From the sensor output time-series data obtained from the sensor output at a specific point in the rising period until the sensor output after being energized is stabilized, by detecting a unique sensor output change pattern of the sensor output in the early stage of fire, A fire detection device for detecting the fire. The fire detection device according to claim 1 ,
The specific sensor output change pattern is:
The fire detection device characterized by the sensor output rising after being temporarily lowered, which is peculiar to the early stage of fire. In the fire detection device according to claim 2 ,
Sensor driving means for driving the catalytic combustion gas sensor at predetermined intervals;
Sensor output acquisition means for acquiring the sensor output at a plurality of the specific time points;
Sensor output time-series data generating means for generating the sensor output time-series data from the plurality of acquired sensor outputs;
Sensor output change pattern storage means for storing the sensor output change pattern in advance;
Based on a comparison result between the sensor output time series data and the sensor output change pattern, comparison detection means for detecting the fire,
An alarm command means for commanding the fire alarm unit that issues a fire alarm to warn the detected fire;
A fire detection device comprising:

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