JP2009295036A - Fire decision device and fire alarm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fire decision device which effectively determines a fire with low power consumption, and a fire alarm using the fire decision device. <P>SOLUTION: The fire decision device includes a smoke sensor 4, a CO sensor 3, a calculation means 2 of calculating a smoke density gradient Gs, a smoke density difference maximum value ¾d¾max, and a CO density gradient Gco, and an elapsed time measuring means 2 of measuring an elapsed time Ts until smoke density reaches first set smoke density and second set smoke density, and determines a fire on the basis of the smoke density gradient Gs, the smoke density difference maximum value ¾d¾max, the elapsed time Ts, and the CO density gradient Gco. Further, the fire decision device includes a detection timing change means of changes first detection timing to second detection timing having an interval longer than that of the first detection timing while smoke density detected by the smoke sensor is between the first set smoke density and the second set smoke density. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fire / non-fire discrimination device and a fire alarm using the fire / non-fire discrimination device.

  Conventional fire alarms include, for example, a thermal sensor that detects temperature rise, a smoke sensor that detects smoke, a flame sensor that detects flame, and a CO sensor that detects carbon monoxide (CO) concentration. There are a single type having a sensor and a composite type having these sensors combined. A ministerial ordinance that establishes technical standards for residential fire alarms and automatic fire alarm equipment for houses stipulates having smoke sensors.

  A smoke fire alarm with a smoke sensor reacts to dust accumulation and cigarette smoke in the living room, and reacts to smoke and water vapor generated during cooking in the kitchen. May occur. For this reason, smoke fire alarms have not been approved for use in the kitchen. However, in recent years, it has become mandatory to install fire alarms in single-family homes, and smoke-based fire alarms have been adopted in the technical standards, and smoke-type fire alarms can be used in the kitchen. It is becoming increasingly important.

  In addition, from an experiment simulating a house fire, there is a fire in which the toxic CO concentration rises before the amount of smoke increases, such as futon kun burning with sleeping cigarettes. Sometimes, in the worst case, there is a risk that the CO concentration or carbon monoxide hemoglobin (COHb) will reach a dangerous area before the smoke fire alarm is given, and will be delayed.

  On the other hand, an international standardization organization (ISO) has proposed an alarm device that detects CO generated together with smoke at the time of a fire and issues an alarm when the CO concentration exceeds a threshold value. The threshold value of CO concentration is determined based on the experiment of EN standard fire test standard TF3, and the threshold value is as low as 50 ppm. However, since the CO concentration generated from the combustion equipment (stove, fan heater, etc.) used on a daily basis can be higher than 50 ppm, such a low CO concentration threshold is used to operate the combustion equipment. May react and give a false alarm.

  As described above, with conventional fire alarms, even if a physical quantity such as smoke that exceeds the threshold is detected, is it due to a fire, or is it due to a non-fire caused by cooking or use of a combustor? It was not possible to make a judgment, and a false alarm was generated or a fire could not be detected early.

In order to solve the above problems, as a conventional fire alarm device, as a method for discriminating between fire and non-fire, 1) a method of changing an operation level according to smoke rising time and comparing it with a threshold (for example, Patent Document 1) 2) A method for setting a fire area and a non-fire area and selecting which area from smoke and CO concentration (for example, refer to Patent Document 2), 3) of smoke and CO concentration A method of determining a fire based on a change rate (for example, see Patent Document 3) has been proposed.
JP 2006-146738 A JP 2006-146843 A JP 2006-277138 A

  In the case of a fire, depending on the type and amount of combustibles, smoke may be emitted gradually or suddenly from a certain point. In the former case, it is possible to distinguish between fire and non-fire by the above-described conventional method, but it is not clear whether the latter case can be effectively distinguished.

  Further, when the fire alarm is a battery-driven type, it is required to extend the life of the battery by suppressing power consumption as low as possible.

  Therefore, in view of the above-described problems, the present invention provides a fire / non-fire discrimination device capable of effectively discriminating between a real fire and a non-fire with low power consumption, and a fire alarm using the fire / non-fire discrimination device. It is intended to provide.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a fire / non-fire discrimination device for discriminating between a fire and a non-fire, a smoke sensor for detecting a smoke concentration, and a CO sensor for detecting a CO concentration. And the smoke density detected at each predetermined first detection timing by the smoke sensor is continuously between the first set smoke density and the second set smoke density set higher than the first set smoke density. And calculating the slope of the linear expression approximated linearly as the smoke density slope Gs based on a plurality of smoke density measured data that fluctuate periodically, and measuring the smoke density measured data and the smoke density represented by the primary expression The maximum value of the difference from the value is calculated as the smoke density difference maximum value | d | max, and is linearly approximated based on the measured data of a plurality of CO concentrations detected at the same time as the measured data of the smoke density Cs. The gradient of the linear expression is the CO concentration gradient Gco Calculating means for calculating the smoke density slope, a smoke density slope judging means for judging whether or not the smoke density slope Gs is less than a preset smoke density slope threshold value, and the smoke density difference maximum value | d | Smoke density difference determining means for determining whether max is less than a preset smoke density difference threshold value, or until the smoke density reaches the second set smoke density from the first set smoke density Elapsed time measuring means for measuring the elapsed time Ts, and elapsed time determining means for determining whether the elapsed time Ts measured by the elapsed time measuring means exceeds a preset elapsed time threshold value. A CO concentration gradient determining means for determining whether the CO concentration gradient Gco exceeds a preset CO concentration gradient threshold, the smoke concentration gradient determining means, the smoke concentration difference determining means, Elapsed time judgment means and Fire determining means for determining a fire according to a combination of determination results of the CO concentration gradient determining means, the smoke concentration gradient determining means, the smoke concentration difference determining means, the elapsed time determining means, and the CO concentration gradient determining means When each of the determination results is not a combination for determining the fire, the non-fire determining means for determining non-fire, and the smoke concentration detected by the smoke sensor is the first set smoke concentration. And a detection timing changing means for changing the first detection timing to a second detection timing having a longer interval while the second set smoke density exists.

  In order to solve the above-mentioned problem, the invention according to claim 2 is the fire / non-fire discrimination device according to claim 1, wherein the detection timing changing means is configured such that the smoke concentration detected by the smoke sensor is the first. When the elapsed time from when the first set smoke density is detected reaches the elapsed time threshold while being between the set smoke density and the second set smoke density, The detection timing is changed to a second detection timing having a longer interval.

  The invention according to claim 3 made to solve the above-mentioned problem is a fire alarm using the fire / non-fire discrimination device according to claim 1 or 2, wherein the fire / non-fire discrimination device fires. And the first fire determination means for determining whether or not the smoke concentration exceeds a predetermined first fire determination smoke threshold, and the first fire determination means And a notifying means for notifying a fire alarm when it is determined that the concentration exceeds the first fire determination smoke threshold value.

  In order to solve the above-mentioned problem, the invention according to claim 4 is the fire alarm device according to claim 3, wherein a predetermined delay time is set when the fire / non-fire discrimination device determines that the fire is not fire. And a second fire judgment in which the smoke concentration is set higher than the first fire judgment smoke threshold over the predetermined delay time set by the delay time setting means. Second fire determination means for determining whether or not the smoke threshold value is exceeded, and the notification means further includes the second fire determination means for causing the smoke density to be determined as the second fire determination smoke. When it is determined that the threshold value is exceeded, a fire alarm is notified.

  According to the first aspect of the present invention, since fire / non-fire is discriminated based on the smoke density gradient Gs, the smoke density difference maximum value | d | max, the elapsed time Ts, and the CO density gradient Gco, it is particularly preferable to use fire and cooking. It is possible to effectively distinguish non-fire due to. In addition, while the smoke density detected by the smoke sensor is between the first set smoke density and the second set smoke density, the first detection timing is changed to the second detection timing having a longer interval. Therefore, it is possible to reduce the power consumption for the operation for distinguishing between fire and non-fire.

  According to the second aspect of the present invention, the detection timing changing means includes the first set smoke while the smoke density detected by the smoke sensor is between the first set smoke density and the second set smoke density. When the elapsed time from the time when the concentration is detected reaches the elapsed time threshold, the first detection timing is changed to the second detection timing with a longer interval. The power consumption can be reduced without dropping.

  According to the third aspect of the present invention, when a fire / non-fire discrimination device determines that a fire has occurred, a fire alarm is notified when the smoke concentration exceeds the first fire determination smoke threshold. Can be detected at an early stage and reliably notified, especially false alarms caused by cooking can be reduced, and a fire alarm particularly suitable for use in a kitchen or the like can be realized.

  According to the fourth aspect of the present invention, when it is determined that the fire / non-fire determination device is non-fire, the smoke concentration is equal to the first fire determination smoke threshold over a predetermined delay time. Since the fire alarm is notified when the value exceeds, false alarms caused by cooking can be reduced.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a fire alarm using a fire / non-fire discrimination device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a fire alarm using a fire / non-fire discrimination device according to an embodiment of the present invention. The fire alarm 1 is a battery-driven fire alarm, which is a microcomputer (hereinafter referred to as a microcomputer) 2, a CO sensor 3, a smoke sensor 4, an alarm output unit 5, an external output unit 6, and a storage unit. 7.

  The microcomputer 2 includes a CPU 2a, a ROM 2b, and a RAM 2c, and the CPU 2a executes various processes including control according to the present embodiment in accordance with a control program stored in the ROM 2b. The RAM 2c appropriately stores data, programs, and the like necessary for the CPU 2a to execute various processes.

  The CO sensor 3 detects the CO concentration in the air and outputs a sensor output corresponding to the CO concentration. The CO sensor 3 may be any sensor that can detect the CO concentration. For example, a catalytic combustion type, an electrochemical type, an NDIR type, or the like is used.

  The smoke sensor 4 detects the amount of smoke in the air and outputs a sensor output corresponding to the amount of smoke. There are various types of smoke sensors. In this embodiment, as the smoke sensor 4, a photoelectric smoke sensor including a light emitting element and a light receiving element that receives irregularly reflected light from smoke particles is used.

  The alarm output unit 5 is for outputting a fire alarm under the control of the microcomputer 2, such as a sound output circuit such as a buzzer or a speech processor that emits an alarm sound or an alarm voice message, or a display output circuit such as an LED or LCD that displays an alarm. Etc. are configured. The external output unit 6 includes a communication circuit that transmits an alarm signal output from the microcomputer 2 to an external system, a security center, or the like.

  The memory | storage part 7 is a non-volatile memory means comprised by EEPROM (Electrically Erasable and Programmable ROM) etc., for example. The storage unit 7 stores a first set smoke density, a second set smoke density, an elapsed time threshold value, a smoke density gradient threshold value, and a CO concentration gradient preset for use in the determination process described later. A threshold value, a smoke concentration difference threshold value, a first fire determination smoke threshold value, a second fire determination threshold value, and a CO alarm concentration value are stored.

  Next, operation | movement of the fire alarm 1 which has the above-mentioned structure is demonstrated. In the present invention, in order to solve the above-described problems, the cooking test and the fire test shown in FIGS. 2 and 3 are performed, and a fire / non-fire discrimination method is obtained based on the test results.

  FIG. 2 shows the cooking test results. In FIG. 2, as the cooking test items, the types and conditions of the objects are “Sanma 1 animal_No ventilation”, “Water oil_No ventilation (1)”, “Water oil_No ventilation (2)”, “Meat Smoke density gradient Gs (smoke density) between Csth1 (% / m) <smoke density Cs <Csth2 (% / m) for “vegetable_no ventilation”, “meat_GT only” and “soy sauce_no ventilation” Cs is set to a first set smoke concentration Csth1 (for example, 2.5)% / m that is set lower than the fire determination smoke threshold, and is set to be lower than the fire determination smoke threshold and higher than the first set smoke concentration. The second set smoke density Csth2 (for example, the smoke density gradient in the smoke density change characteristic while continuously fluctuating between 6% / m) and the smoke of | (actual measurement value) − (primary expression) | Elapsed time Ts between the maximum density difference | d | max and Csth1 <Cs <Csth2 (smoke density C And the CO concentration gradient Gco between Csth1 <Cs <Csth2 (the smoke concentration Cs is the first set smoke concentration Csth1 and the second set smoke concentration Csth2). The CO concentration gradient in the CO concentration change characteristic during continuous fluctuations between

  Here, “sanma_no ventilation” is a test using a fish grilling net, burning saury, generating smoke, and not operating a ventilation fan. “Water / oilless (1)” is a test in which a frying pan was heated for about 30 seconds with high heat, 15 cc of oil was added, and 10 cc of water was added after about 30 seconds to generate smoke. “Meat vegetables_no ventilation” is a test in which pork belly is fried to some extent in a frying pan, vegetables are added, smoke is generated, and the ventilation fan is not operated. “Meat_GT only” is a test in which pork loin is baked in a frying pan, smoke is generated, and only the ventilation fan GT is operated.

  FIG. 3 shows the fire test results. In FIG. 3, smoke concentration gradient Gs for fire test items, smoldering, trash can, cotton wick, stove duvet (100% cotton), stove duvet (50% cotton poly), wood, urethane and tempura oil , Smoke density difference maximum value | d | max, elapsed time Ts, and CO concentration gradient Gco are shown.

  For example, “kun-yaki” is a test in which a heater serving as a fire source is sandwiched between 100% cotton futon and heated at 450 ° C. for 17 minutes to generate a smoldering fire. "Trash" means that tissue and advertising paper are rolled up into a nearly cylindrical polypropylene trash can, and 25 cigarettes folded in half and 3 lit cigarettes in a paper tray folded with advertising paper. Fired. The “cotton wick” is a bundle of 30 pieces of cotton twisted like a candle core, hung away from the floor, ignited with a lighter or the like, and smoked. "Stove futon (100% cotton)" is a situation where a 100% cotton futon is placed in contact with a heater so as to face a reflective electric stove with a 1kW reflector, and the stove is ignited to generate a fire. Tested. “Wood” refers to a dried beech stick (1 × 2 × 25 cm) placed on a hot plate and heated to produce smoke. “Urethane” is a stack of four polyurethanes that are ignited with 10 cc of ethanol to cause a fire. “Tempura oil” is obtained by putting a vegetable oil in a pot and continuously heating it with an electric heater to ignite it, thereby generating a fire.

  The fire test was conducted in a fire test room simulating the residence of a general house, and the cooking test was conducted in a cooking test room simulating a kitchen of a general house.

  FIG. 4 is a diagram schematically showing a cooking test room simulating a kitchen of a general house. As shown in FIG. 4, in a room in which a gas table GR is arranged at one corner of a room, a large ventilation fan GT is arranged on the upper wall, and a small ventilation fan R is arranged on the ceiling, the gas table GR is used and The cooking test was performed with the ventilation fans GT and R not being driven. Then, CO concentration and smoke concentration data were collected for the case where measurement was performed with the fire alarm 1 arranged on the wall facing the wall with the door D, that is, the right wall of the gas table GR.

  FIG. 5 is a diagram schematically showing a fire test chamber. As shown in FIG. 5, with the fire alarm 1 placed on the top of the wall facing the wall with the sliding door HD and the vent V and the fire source placed near the center of the floor, the CO concentration and smoke concentration Data was collected.

  The calculation method of the smoke density gradient Gs and the smoke density difference maximum value | d | max in FIGS. 2 and 3 is as follows. For example, consider the case where the smoke density Cs generated by fire or cooking changes as shown in FIG. 5 while rising from Csth1 to Csth2. In FIG. 5, the measurement time t0, t2, t3,. . . , Tn are measured data of smoke density Cs detected at Cs0, Cs1, Cs2, Cs3,. . . , Csn. The detection timing is the first detection timing (1 second interval) from the initial t0 to t100, but for the reason to be described later, the second detection interval that is longer than the first detection timing from the middle (t100). The detection timing is switched to 10 seconds.

The trapezoidal area formed by the smoke density Cs0 at time t0 and the smoke density Cs1 at time t1 (time integrated value of the smoke density Cs) is A1, and is formed by the smoke density Cs1 at time t1 and the smoke density Cs2 at time t2. The area of the trapezoidal part is A2, and the area of the trapezoidal part formed in the same manner is A3, A4, A5,. . . , An, and the area of each trapezoidal part is obtained. Finally, the total area (time integrated value of smoke density Cs from time t0 to tn) S, which is the sum of all trapezoidal parts from time t0 to time tn, is as follows: Ask.
S = ΣAn (1)

Next, the smoke density Cs0 at the time t0 and the area of the rectangular portion formed between the times t0 and tn (a constant portion of the integrated value of the smoke density Cs from the time t0 to tn) Ss are obtained as follows.
Ss = Cs0 × (tn−t0) (2)

Next, the area Ss of the rectangular portion is subtracted from the total area S, and an upper area (a variation portion of the integrated value of the smoke density Cs from time t0 to tn) St obtained by removing the rectangular portion from the trapezoidal portion is obtained.
St = S−Ss (3)

Next, assuming a triangle having an area comparable to the obtained St between times t0 and tn, and assuming that the height is h, it can be expressed by the following equation.
St = {(tn−t0) × h} / 2 (4)

Next, the height h is obtained from the above equation (4).
h = 2St / (tn-t0) (5)

Next, when the obtained height h is divided by (tn−t0), the smoke concentration gradient Gs (% / m / sec) is obtained as follows as the average gradient of the smoke concentration Cs from the time t0 to the time tn. .
Gs = h / (tn−t0) = 2St / (tn−t0) ² (6)

As described above, the smoke density gradient Gs can be obtained. Then, when the change in the smoke density Cs during the time t from the time t0 to the time tn is expressed in the form of the primary expression y = ax + b, the following has the smoke density gradient Gs (= a) obtained as described above. The linear expression can be approximated by a linear expression.
Cs = {2St / (tn−t0) ² } t + b (7)
Here, t is time and b is an intercept.

  And the measured data Cs0, Cs1, Cs2, Cs3,. . . , Csn and the smoke density value represented by the linear expression approximated by the above-mentioned linear approximation, the maximum value is calculated as the smoke density difference maximum value | d | max.

  The CO concentration gradient Gco can also be obtained in the same manner as the method for calculating the smoke concentration gradient Gs described above based on the CO concentration during the time t0 to tn, but the description thereof is omitted here.

  FIG. 7 shows, as an example, (a) a graph representing the measured value of the smoke concentration Cs and the linear expression obtained as described above from the measured value in the case of the cooking test “one samurai_GT + R”, and (b ) It is a graph showing the density difference between the measured value and the primary expression. In the graph of FIG. 7A, the linear expression is represented by Cs = 0.01t−2.106. From the graph of FIG. 7B, the maximum value of | (actual value) − (primary expression) | It can be seen that d | max is 1.438.

  From the experimental results shown in FIGS. 2 and 3, the parameters for fire / non-fire determination are set to Gs <so that the object of the fire test is determined to be fire and the object of the cooking test is determined to be non-fire. th1 (th1 is an optimum value by verification with an actual machine, for example, in a range of 0.15 to 0.18), | d | max <th2 (th2 is an optimum value by verification with an actual machine, For example, it is in the range of 1.4 to 1.7.), Ts> th3 (th3 is an optimum value by verification with an actual machine, for example, in the range of 20 to 50 seconds) and Gco> th4 ( th1 is an optimum value obtained by verification with an actual machine, and is set in a range of 0.4 to 0.6, for example.

Combining the parameters set as described above, the following judgment conditions are used to distinguish between fire and non-fire and whether the fire is a smoldering fire or a general fire other than a smoldering fire. I did it.
Discrimination condition A. If Gs <th1 and Gco> th4, it is determined that the fire is fired.
Discrimination condition B. If Gs <th1 and | d | max <th2 and Ts> th3, it is determined as a smoldering fire.
Discrimination condition C.I. If | d | max <th2 and Gco> th4, it is determined as a general fire.
Discrimination condition D. If Gs <th1 and | d | max <th2, it is determined as a general fire.
Discrimination condition E.E. If none of the above applies, it is determined as non-fire.
The priority order of each condition is A>B>C>D> E.

  FIG. 8 is a diagram showing a fire / non-fire discrimination pattern based on the discrimination conditions described above. In this fire / non-fire discrimination pattern, th1, th2, th3, and th4 are set as a smoke concentration gradient threshold value, a smoke concentration difference threshold value, an elapsed time threshold value, and a CO concentration gradient threshold value, respectively. Stored in the unit 7.

  As a result of the determination based on the above-mentioned fire / non-fire determination conditions, when it is determined that the fire is detected, the alarm delay time is set to 0 second and the smoke concentration Cs is increased to 8% / m, for example. Announce a fire alarm. A general fire determination smoke threshold is 10% / m. In the present invention, the fire detection sensitivity is increased by setting a smoke concentration lower than that as the fire determination smoke threshold.

  On the other hand, if it is determined as non-fire as a result of the determination based on the above-mentioned fire / non-fire determination condition, the alarm delay time is set to 45 seconds, for example, and the fire determination smoke threshold is set to 10% as a general value. / M, and fire alarm is notified 45 seconds after smoke density Cs rises to 10% / m. However, if the smoke density Cs becomes less than 10% / m during 45 seconds, the 45-second count by the timer is reset and the 45-second count is started again. When the smoke density Cs becomes less than 10% / m, the alarm is released.

  Next, refer to the flowcharts shown in FIGS. 9 to 12 for the detailed operation of the fire detection process of the fire alarm executed by the control of the CPU 2a of the microcomputer 2 based on the setting of the fire / non-fire discrimination condition as described above. While explaining.

  In FIG. 10, the CPU 2a first reads the sensor outputs of the CO sensor 3 and the smoke sensor 4 at every first detection timing (for example, every second) after power-on (step S1), and then reads the read CO 2. Based on the sensor outputs of the sensor 3 and the smoke sensor 4, a conversion calculation process for obtaining the CO concentration Cco and the smoke concentration Cs is performed (step S2).

  Next, the CPU 2a determines whether or not the obtained smoke density Cs exceeds a preset first set smoke density Csth1 (step S3). If the smoke density Cs does not exceed Csth1 (N in Step S3), then the process returns to Step S3, and if it exceeds (Y in Step S3), then the elapsed time Ts until the smoke density Cs reaches Csth2 from Csth1 Is started (step S4: elapsed time measuring means). The reason why the first set smoke density Csth1 is set to 2.5% is that the output fluctuation error of the smoke sensor 4 is estimated to be about 1% / m, for example, and an unnecessary fire / This is to prevent the non-fire discrimination logic from operating. The reason why the second set smoke density is set to 6% is that the appraisal standard is “no ringing at 5% / m for 5 minutes” and the first fire determination threshold value in the fire determination described later. Is set in a range of 7 to 10% / m.

  Next, the CPU 2a stores the obtained smoke density Cs, CO density Cco, and Ts count value in the storage unit 7 (step S5). Next, the CPU 2a reads the sensor outputs of the CO sensor 3 and the smoke sensor 4 at every first detection timing (every second) (step S6), and then the sensor outputs of the read CO sensor 3 and smoke sensor 4 Based on the above, conversion calculation processing for obtaining the CO concentration Cco and the smoke concentration Cs is performed (step S7).

  Next, the CPU 2a determines whether or not the smoke density Cs exceeds a preset second smoke density Csth2 (step S8). If the smoke density Cs does not exceed Csth2 (N in step S8), the CPU 2a then sets the elapsed time from the time when the first set smoke density Csth1 is detected to a preset elapsed time threshold th3. In other words, it is determined whether or not the count value of the elapsed time Ts is equal to th3 (step 8A). If the count value of the elapsed time Ts is not equal to th3 (N in step S8A), the process returns to step S5. If the count value of the elapsed time Ts is equal to th3 (Y in step S8A), the CPU 2a then changes the detection timing from the first detection timing (for example, every second) to a second detection timing (for example, longer than that). (Every 10 seconds) (step S8B), and then returns to step S5. Therefore, after the Ts count value reaches th3, the sensor output is read at the second detection timing (every 10 seconds).

  Here, the reason for changing the detection timing from the first detection timing (for example, every 1 second) to the second detection timing (for example, every 10 seconds) is because the light emitting element and the light receiving element of the smoke sensor 4, the CPU 2a, the memory This is to keep the operating power consumed by the unit 7 and the like low. The reason for setting the detection timing change time as the time when the count value of Ts reaches th3 is that if Ts exceeds the elapsed time threshold value th3 in step S21 described later, it is determined that a smoldering fire has occurred. In addition, in the results of the cooking experiment and the fire experiment from FIG. 2 and FIG. 3, each parameter (Gs, | d | max, Ts, Gco, etc.) is used as the second detection timing after th3 seconds. This is because there is no hindrance in the calculation of.

  On the other hand, if the smoke density Cs exceeds Csth2 (Y in step S8), then the CPU 2a calculates the smoke density gradient Gs, the smoke density difference maximum value | d | max, and the CO density gradient Gco (step). S9: Calculation means). For example, the smoke density gradient Gs and the smoke density difference maximum value | d | max are calculated by continuously varying the smoke density Cs converted from the measured sensor output from the smoke sensor 4 between Csth1 and Csth2. It is calculated by the above-described calculation method based on the measured data of a plurality of smoke densities Cs. The slope Gco of the CO concentration Cco is calculated by, for example, measuring a plurality of smoke concentrations Cs in which the smoke concentration Cs converted by the sensor output from the smoke sensor 4 continuously varies between Csth1 and Csth2. It is calculated by the above-described calculation method based on the actual measurement data of the CO concentration Cco detected at the same time as the data. In addition, when the measured data becomes Csth1 or less even once, the calculation is canceled, and the measured data of a plurality of smoke concentrations Cs that continuously vary between Csth1 and Csth2 are restarted from the time when Csth1 is exceeded. Calculations are made based on this.

  Next, the CPU 2a sets all of the Gs_flag, | d | max_flag, Ts_flag, and Gco flag to “0” and stores them in the storage unit 7 (step S10).

  Next, the CPU 2a determines whether or not the smoke density gradient Gs is less than a preset smoke density gradient threshold th1 (step S11: smoke density gradient determination means). If the smoke density gradient Gs is less than th1 (Y in step S11), then the step CPU 2a rewrites the Gs_flag stored in the storage unit 7 from “0” to “1” (step S12), and then step Proceed to S13. If the smoke density gradient Gs is not less than th1 (N in step S11), the process proceeds to step S13.

  In step S13 (smoke density difference determination means), the CPU 2a determines whether or not | d | max is less than a preset smoke density difference threshold th2. If | d | max is less than th2 (Y in step S13), then the CPU 2a rewrites the | d | max_flag stored in the storage unit 7 from “0” to “1” (step S14). Next, the process proceeds to step S15. If | d | max is not less than th2 (N in step S13), the process directly proceeds to step S15.

  In step S15 (elapsed time determination means), the CPU 2a determines whether or not the elapsed time Ts exceeds a preset elapsed time threshold th3. If the elapsed time Ts exceeds th3 (Y in step S15), the CPU 2a then rewrites the Ts_flag stored in the storage unit 7 from “0” to “1” (step S16), and then step S17. Proceed to If Ts does not exceed th3 (N in Step S15), the process proceeds to Step S17 as it is.

  In step S17 (CO concentration gradient determination means), the CPU 2a determines whether or not the CO concentration gradient Gco exceeds a preset CO concentration gradient threshold th4. If the CO concentration gradient Gco exceeds th4 (Y in step S17), the CPU 2a then rewrites the Gco_flag stored in the storage unit 7 from “0” to “1” (step S18), and then step Proceed to S19. If Gco does not exceed 0th4 (N in step S17), the process directly proceeds to step S19.

  Next, the CPU 2a determines whether or not the Gs_flag stored in the storage unit 7 is “1” and the Gco_flag is “1” (step S19). If the Gs_flag is “1” and the Gco_flag is “1” (Y in step S19), the CPU 2a then determines that the fire type is smoldering fire based on the fire / non-fire determination pattern shown in FIG. (Step S20), and then proceeds to the fire determination process of Step S30.

  If the Gs_flag is not “1” and the Gco_flag is not “1” (N in step S19), then the CPU 2a indicates that the Gs_flag is “1”, the | d | max_flag is “1”, and the Ts_flag is “1”. "Is determined (step S21). If the Gs_flag is “1”, the | d | max_flag is “1”, and the Ts_flag is “1” (Y in step S21), then the CPU 2a performs the fire / non-fire determination pattern shown in FIG. Then, the fire type is determined to be a smoldering fire (step S22), and then the process proceeds to the fire determination process of step S30.

  If the Gs_flag is not “1” and the | d | max_flag is “1” and the Ts_flag is not “1” (N in Step S21), then the CPU 2a determines that the | d | max_flag is “1” and the Gco_flag. Is determined to be “1” (step S23). If the | d | max_flag is “1” and the Gco_flag is “1” (Y in step S23), then the CPU 2a sets the fire type to general fire based on the fire / non-fire discrimination pattern shown in FIG. (Step S24), and then proceeds to the fire determination process of step S30.

  If the | d | max_flag is not “1” and the Gco_flag is “1” (N in step S241), then the CPU 2a determines whether the Gs_flag is “1” and the | d | max_flag is “1”. Is determined (step S25). If the Gs_flag is “1” and the | d | max_flag is “1” (Y in step S25), then the CPU 2a sets the fire type to general fire based on the fire / non-fire discrimination pattern shown in FIG. (Step S26), and then the process proceeds to a fire determination process in step S30.

  If the Gs_flag is not "1" and the | d | max_flag is not "1" (N in step S25), then the CPU 2a sets the fire type to non-fire based on the fire / non-fire discrimination pattern shown in FIG. (Step S27).

  If it is determined in step S27 that there is no fire, then the CPU 2a determines whether or not the CO concentration is equal to or higher than the CO alarm concentration (for example, 300 ppm) (step S28). If the CO concentration is equal to or higher than the CO alarm concentration (Y in step S28), then the CPU 2a re-determines the fire type as smoldering (step S29), and then proceeds to the fire determination process in step S30. If the CO concentration is not equal to or higher than the CO alarm concentration (N in step S28), the process proceeds to the non-fire determination process in step S31.

  If it is determined in step S28 that the CO concentration is equal to or higher than the CO alarm concentration, the reason for re-determining that the non-fire is determined as a smoldering fire is as follows.

  That is, among those determined as non-fire, any of the parameters such as Gs, | d | max, Ts, Gco, etc. indicates non-fire depending on various conditions even though a fire has actually occurred. In some cases, this tendency is often judged as non-fire, especially in the case of a smoldering fire. For example, as the smoke concentration Cs increases from Csth1 to Csth2 by many smoldering fire tests, the increase in the CO concentration is very slow, and any of the parameters Gs, | d | max, Ts, Gco Is known to be a non-fire value. It has also been found that the CO concentration when the smoke concentration becomes Csth2 or more is higher than the CO alarm concentration in all the numerous smoldering fire tests.

  On the other hand, in the CO alarm device that detects the CO alarm by detecting the CO concentration, the JIA test regulation 6.2 “Incomplete combustion gas detection part reliably and promptly detects the generated carbon monoxide. "In the case of a smoldering fire, when the smoke concentration becomes Csth2 or more, the CO alarm is already set to CO. It is considered that an alarm has been issued.

  Therefore, even if it is determined in step S27 that there is no fire, if it is determined in step S28 that the CO concentration is greater than or equal to the CO alarm concentration, a fire such as a smoldering fire may have occurred. For this reason, it is determined again as a smoldering fire in step S29, and the process proceeds to the fire determination process in step S30.

  As described above, the CPU 2a determines fire / non-fire according to the fire / non-fire determination pattern of FIG. 8, and selects the fire determination process of step S30 or the non-fire determination process of step S31 according to the determination result.

  Next, in the fire determination process in step S30, as shown in the flowchart of FIG. 11, the CPU 2a first sets a delay time T = 0 seconds (step S301), and then the smoke density Cs is set in advance. It is determined whether or not a set first fire determination smoke threshold value is exceeded, for example, 8% / m (set lower than a general 10% / m) (step S302).

  If the smoke density Cs exceeds the first fire determination smoke threshold value (Y in step S302), the CPU 2a then issues an alarm notifying the occurrence of a fire (step S303). That is, the CPU 2a generates an alarm signal and outputs the alarm signal to the alarm output unit 5. The alarm output unit 5 issues an alarm by sounding an alarm sound or displaying an alarm display. Moreover, the external output part 6 sends out the message | telegram etc. for alert | reporting a fire outbreak to an external system, a security center, etc. as needed.

  Next, the CPU 2a determines whether or not the smoke density Cs is below the first fire determination smoke threshold (step S304). If the smoke density Cs is not lower than the first fire determination smoke threshold value (N in step S304), the process returns to step S303, and the alarm is continued. If the smoke density Cs is below the first fire determination smoke threshold (Y in step S304), the CPU 2a then cancels the fire alarm (step S305), and then returns to step S301.

  On the other hand, if the smoke concentration Cs does not exceed the first fire determination smoke threshold value in step S302 (N in step S302), the CPU 2a then determines whether or not the smoke concentration Cs is less than Csth1. (Step S286). If the smoke density Cs is not lower than Csth1 (N in Step S308), the process returns to Step S302. If the smoke density Cs is lower than Csth1 (Y in Step S306), the process returns to Step S3 in FIG.

  Thus, in the fire determination process of step S30, it is determined whether or not the smoke density Cs exceeds the first fire determination smoke threshold at the delay time T = 0 seconds, and if it exceeds, a fire alarm is issued. .

  Next, in the non-fire determination process of step S31, as shown in the flowchart of FIG. 12, the CPU 2a first sets the delay time T = 45 seconds and starts counting the delay time counting timer t ( Step S311). Next, the CPU 2a determines whether or not the smoke density Cs exceeds a preset second fire determination smoke threshold of 10% / m (set to a general value) (step S312).

  If the smoke density Cs exceeds the second fire determination smoke threshold (Y in step S312), the CPU 2a then determines whether or not the timer count t has reached T = 45 seconds or more ( Step S313). If the timer count t is not T = 45 seconds or more (N in step S313), the process returns to step S312. If the timer count t is equal to or greater than T = 45 seconds (Y in step S313), the CPU 2a then issues an alarm notifying the occurrence of a fire (step S314). That is, the CPU 2a generates an alarm signal and outputs the alarm signal to the alarm output unit 5. The alarm output unit 5 issues an alarm by sounding an alarm sound or displaying an alarm display. Moreover, the external output part 6 sends out the message | telegram etc. for alert | reporting a fire outbreak to an external system, a security center, etc. as needed.

  Next, the CPU 2a determines whether or not the smoke density Cs falls below the second fire determination smoke threshold (step S315). If the smoke density Cs is not lower than the second fire determination smoke threshold value (N in step S315), the process returns to step S314, and the alarm is continued. If the smoke density Cs is below the second fire determination smoke threshold (Y in step S315), the CPU 2a then cancels the fire alarm (step S316), and then returns to step S311.

  On the other hand, if the smoke density Cs does not exceed the second fire determination smoke threshold value in Step S312, the CPU 2a resets the timer count t (Step 317). Then, it is determined whether or not the smoke density Cs is lower than Csth1 (step S318). If the smoke density Cs is not lower than Csth1 (N in Step S318), then the process returns to Step S312. If the smoke density Cs is lower than Csth1 (Y in Step S318), then the process returns to Step S3 in FIG.

  In this way, in the non-fire determination process of step S31, the delay time T = 45 seconds is set, and the smoke density Cs must exceed the second fire determination smoke threshold before the delay time T = 45 seconds. If this is the case, it will be judged as non-fire and a fire alarm will not be issued. However, if the smoke density Cs exceeds the second fire determination smoke threshold before the delay time T = 45 seconds, it is determined that the fire is not a non-fire but a fire alarm is issued. That is, even when it is determined that there is no fire in step S27 of FIG. 10 and the process proceeds to the non-fire determination process (FIG. 12) of step S31, the smoke concentration Cs is long for the second fire determination as in the set delay time. If it exceeds the smoke threshold, it is judged as a real fire and a fire alarm is issued. Therefore, not only false alarms during non-fire based on generation of temporary CO and smoke such as cigarettes, but also false alarms during non-fire based on CO and smoke generated during cooking are reduced. become.

  As is clear from the above description, in the flowcharts of FIGS. 9 and 10, step S4 corresponds to the elapsed time measuring means in the claims, steps S8A and S8B correspond to the detection timing changing means in the claims, and step S9. Corresponds to the calculation means in the claims, step S11 corresponds to the smoke concentration slope determination means in the claims, step S13 corresponds to the smoke density difference determination means in the claims, and step S15 corresponds to the elapsed time determination means in the claims. Steps S20, 22, 24, and 26 correspond to the fire determination means in the claims, step S27 corresponds to the non-fire determination means in the claims, and step S28 corresponds to the CO concentration determination means in the claims. It is processing. In the flowchart of FIG. 11, step S302 corresponds to the first fire determination means in the claims, and step S303 corresponds to the notification means in the claims. In FIG. 12, step S311 corresponds to the delay time setting means in the claims, step S312 corresponds to the second fire determination means in the claims, and step S314 corresponds to the notification means in the claims. ing.

  As described above, according to the present invention, it is possible to effectively distinguish between a fire and a non-fire according to the degree of increase in the smoke concentration, reliably notify the fire, and particularly reduce false alarms due to cooking. it can. In addition, when it is determined that the CO concentration is equal to or higher than the CO alarm determination threshold after it is determined as non-fire, it is determined again as fire, so that it is possible to improve the accuracy of fire determination such as smoldering fire. Further, since the detection timing is changed from the first detection timing (for example, 1 second) to the second detection timing (for example, 10 seconds) having a longer interval, the light emitting element of the smoke sensor is changed than when the detection timing is not changed. In addition, the power consumed by the light receiving element, the CPU 2a, the storage unit 7, and the like can be kept low.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various deformation | transformation and application are possible.

  For example, if it is determined in step S28 in FIG. 10 that the CO concentration is equal to or higher than the CO alarm concentration and the process proceeds to the fire determination process in step S30, the first in steps S302 and S304 in FIG. The fire determination smoke threshold may be switched to a lower value (for example, 7% / m) to make it easier to generate a fire alarm.

  In the above-described embodiment, the case where the present invention is applied to a fire alarm device has been described. However, the present invention is not limited to this, and the present invention can also be applied to a combined alarm device having both functions of a CO alarm device and a fire alarm device.

It is a block diagram which shows the structure of the fire alarm using the fire / non-fire discrimination apparatus which concerns on embodiment of this invention. It is a figure which shows a cooking test result. It is a figure which shows a fire test result. It is a figure which shows roughly the cooking test room which imitated the kitchen of the general house. It is a figure which shows a fire test chamber schematically. It is a figure for demonstrating the calculation method of smoke density inclination Gs and smoke density difference maximum value | d | max. (A) is an example of a graph representing the measured value of the smoke concentration and the primary expression obtained as described above from the measured value, and (b) is an example of a graph representing the density difference between the measured value and the primary expression. FIG. It is a figure which shows a fire / non-fire discrimination pattern. It is a flowchart which shows the detailed operation | movement of the fire detection process of the fire alarm device of FIG. It is a flowchart which shows the detailed operation | movement of the fire detection process of the fire alarm device of FIG. It is a flowchart which shows the detailed operation | movement of the fire detection process of the fire alarm device of FIG. It is a flowchart which shows the detailed operation | movement of the fire detection process of the fire alarm device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fire alarm device 2 Microcomputer 2a CPU (Calculation means, smoke concentration inclination determination means, CO concentration inclination determination means, CO concentration determination means, elapsed time measurement means, elapsed time determination means, fire determination means, non-fire determination means, first Fire determination means, second fire determination means, delay time setting means, part of notification means, detection timing changing means)
3 CO sensor 4 Smoke sensor 5 Alarm output part (part of the notification means)
7 Memory part

Claims (4)

A fire / non-fire discrimination device that distinguishes between fire and non-fire,
A smoke sensor for detecting smoke concentration;
A CO sensor for detecting the CO concentration;
The smoke density detected at each predetermined first detection timing by the smoke sensor is continuously between the first set smoke density and the second set smoke density set higher than the first set smoke density. Based on a plurality of fluctuating measured data of the smoke density, a slope of a linear expression approximated by a straight line is calculated as a smoke density slope Gs. Is calculated as a smoke density difference maximum value | d | max, and is linearly approximated based on a plurality of measured CO concentration data detected simultaneously with the measured data of the smoke density Cs. Calculating means for calculating the slope of the equation as the CO concentration slope Gco;
A smoke concentration gradient determining means for determining whether the smoke concentration gradient Gs is less than a preset smoke concentration gradient threshold;
Smoke density difference determining means for determining whether or not the smoke density difference maximum value | d | max is less than a preset smoke density difference threshold value;
An elapsed time measuring means for measuring an elapsed time Ts until the smoke density reaches the second set smoke density from the first set smoke density;
Elapsed time determining means for determining whether or not the elapsed time Ts measured by the elapsed time measuring means exceeds a preset elapsed time threshold;
CO concentration gradient determination means for determining whether or not the CO concentration gradient Gco exceeds a preset CO concentration gradient threshold;
Fire determining means for determining a fire according to a combination of the determination results of the smoke concentration gradient determining means, the smoke concentration difference determining means, the elapsed time determining means and the CO concentration gradient determining means;
When the determination results of the smoke concentration gradient determination unit, the smoke concentration difference determination unit, the elapsed time determination unit, and the CO concentration gradient determination unit do not correspond to the combination for determining the fire, a non-fire Non-fire discrimination means to discriminate
While the smoke density detected by the smoke sensor is between the first set smoke density and the second set smoke density, the first detection timing is changed to a second detection timing with a longer interval. Detection timing changing means for
A fire / non-fire discrimination device characterized by comprising: In the fire / non-fire discrimination device according to claim 1,
The detection timing changing means is a point in time when the first set smoke density is detected while the smoke density detected by the smoke sensor is between the first set smoke density and the second set smoke density. The fire / non-fire discrimination device is characterized in that when the elapsed time from the time reaches the elapsed time threshold, the first detection timing is changed to a second detection timing having a longer interval. A fire alarm using the fire / non-fire discrimination device according to claim 1 or 2,
First fire determination means for determining whether or not the smoke concentration exceeds a predetermined first fire determination smoke threshold when the fire / non-fire determination device determines that a fire has occurred;
Informing means for informing a fire alarm when the first fire judging means judges that the smoke concentration exceeds the first fire judging smoke threshold value;
A fire alarm device comprising: In the fire alarm according to claim 3,
A delay time setting means for setting a predetermined delay time when it is determined as a non-fire by the fire / non-fire determination device;
Whether the smoke density exceeded a second fire determination smoke threshold set in advance higher than the first fire determination smoke threshold over the predetermined delay time set by the delay time setting means And a second fire determination means for determining whether or not
The notification means further notifies a fire alarm when the second fire determination means determines that the smoke concentration exceeds the second fire determination smoke threshold value. .

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