JP7549506B2 - Fire detection device, disaster prevention equipment, and fire detection method - Google Patents

Description

The present invention relates to a photoelectric fire detection device, disaster prevention equipment, and a fire detection method that detects fires by observing smoke caused by fires.

Conventionally, photoelectric smoke detectors, which are fire detection devices, observe the smoke density by receiving scattered light generated when a light-emitting element shines light on smoke that has flowed into a smoke detection space, and detect a fire when the observed smoke density meets predetermined fire judgment conditions, causing a receiver to, for example, sound a fire alarm.

In addition, to reduce current consumption, the smoke detector uses intermittent light emission to observe smoke concentration by driving the light-emitting element to emit light at a predetermined interval.

Japanese Utility Model Application Publication No. 5-30990 Japanese Patent Application Laid-Open No. 63-167242

However, in such conventional smoke detectors, the change over time in smoke concentration due to smoke generated by a fire is observed discretely in accordance with the cycle of the intermittent light emission. If the cycle of the intermittent light emission becomes long, the change over time in smoke concentration cannot be observed accurately, and the accuracy of fire detection decreases.

In addition, to detect fires with high accuracy from observed smoke concentrations, it is necessary to calculate and judge smoke features specific to a fire from observational data that includes multiple smoke concentrations that change continuously over time. However, with multiple smoke concentrations that are observed discretely due to intermittent light emission, the time intervals between each smoke concentration are too far apart, and the temporal changes in smoke concentration during that time are lost, making it difficult to capture smoke features specific to a fire.

The present invention aims to provide a smoke detection device, disaster prevention equipment, and fire detection method that enable highly accurate fire detection by accurately observing changes in smoke concentration over time.

(Fire detection device 1)
The present invention provides a fire detection device,
an observation unit that irradiates smoke that has flowed into a smoke detection space from a predetermined monitoring area with a detection light and receives scattered light or attenuated light generated to observe smoke concentration;
a processing unit that continuously emits detection light to observe smoke concentration and generates observation data including a plurality of observation values obtained continuously in time series at predetermined intervals;
A detection unit that detects a fire based on the observation data;
The present invention is characterized in that:

(Fire detection device 2)
As another aspect of the present invention, there is provided a fire detection device, comprising:
an observation unit that irradiates smoke that has flowed into a smoke detection space from a predetermined monitoring area with a detection light and receives scattered light or attenuated light generated to observe smoke concentration;
a processing unit that, when the smoke density observed by intermittently emitting the detection light satisfies a predetermined threshold condition, continuously emits the detection light to observe the smoke density, and generates observation data including a plurality of observation values obtained continuously in a time series for each predetermined time period;
A detection unit that detects a fire based on the observation data;
The present invention is characterized in that:

(Fire detection by the detection unit)
The detection unit is
A predetermined feature is detected from a plurality of observation values contained in the observation data, and a fire is detected if the feature satisfies a predetermined fire judgment condition.

(Fire Judgment Based on Features 1)
The detection unit determines that a fire has occurred when the feature amount detected at each predetermined time is equal to or exceeds a predetermined threshold value.

(Fire detection based on features 2)
The detection unit determines that a fire has occurred when the feature amount detected at each predetermined time is equal to or exceeds a predetermined threshold value a predetermined number of times in succession.

(Fire detection based on features 3)
The detection unit determines that a fire has occurred when a ratio of a current feature amount to a previous feature amount detected at a predetermined time interval is equal to or exceeds a predetermined threshold value.

(Fire detection based on features 4)
The detection unit determines that a fire has occurred when a ratio of a current feature amount to a previous feature amount detected at a predetermined time interval is equal to or exceeds a predetermined threshold value a predetermined number of times in succession.

(Fire Judgment Based on Features 5)
The detection unit determines that a fire has occurred when a difference between a current feature amount and a previous feature amount detected at a predetermined time interval is equal to or exceeds a predetermined threshold value.

(Fire Judgment Based on Features 6)
The detection unit determines that a fire has occurred when a difference between a current feature amount and a previous feature amount detected at a predetermined time interval is equal to or exceeds a predetermined threshold value a predetermined number of times in succession.

(Features)
The detection unit detects an integral value, an average value, or a peak value of a plurality of observation values included in the observation data as a feature amount of the observation data.

(Disaster prevention equipment 1)
In the disaster prevention equipment using the above-mentioned fire detection device,
A fire alarm system includes a receiver and a detector that detects a fire and transmits a fire signal to the receiver.
The sensor is characterized by having an observation section, a processing section, and a detection section.

(Disaster prevention equipment 2)
In the disaster prevention equipment using the above-mentioned fire detection device,
A fire alarm system includes a receiver and a detector that detects a fire and transmits a fire signal to the receiver.
The detector is provided with an observation section and a processing section,
The receiver is characterized by having a detection unit.

(Fire detection method 1)
The present invention provides a fire detection method, comprising:
The observation unit irradiates the smoke that has flowed into the smoke detection space from the predetermined monitoring area with the detection light, receives the scattered light or attenuated light generated, and observes the smoke concentration;
A processing unit continuously emits detection light to observe smoke concentration, and generates observation data including a plurality of observation values obtained continuously in a time series for each predetermined time period;
A detection unit detects a fire based on the observation data.
It is characterized by:

(Fire detection method 2)
The present invention provides a fire detection method, comprising:
The observation unit irradiates the smoke that has flowed into the smoke detection space from the predetermined monitoring area with the detection light, receives the scattered light or attenuated light generated, and observes the smoke concentration;
a processing unit, when the smoke density observed by intermittently emitting the detection light satisfies a predetermined threshold condition, continuously emitting the detection light to observe the smoke density, and generating observation data including a plurality of observation values obtained continuously in a time series for each predetermined time period;
A detection unit detects a fire based on the observation data.
It is characterized by:

(Fire detection method by detection unit)
In a fire detection method,
The detection unit is
A predetermined feature amount is detected from a plurality of observation values contained in the observation data, and a fire is detected when the feature amount satisfies a predetermined fire judgment condition.

(Basic Effects of Fire Detection Device 1)
According to the fire detection device of the present invention, by continuously emitting detection light and observing smoke concentration, observation data containing multiple successive smoke concentrations in a time series is generated, and fires can be detected with high accuracy based on the observation data that accurately shows the changes in smoke concentration over time.

(Basic Effects of Fire Detection Device 2)
According to the fire detection device of the present invention, when the smoke density observed by intermittent emission of detection light satisfies a predetermined threshold condition, for example, when the smoke density increases to above a predetermined threshold that can be considered a sign of a fire, the detection light is continuously emitted to observe the smoke density, thereby generating observation data including multiple successive smoke densities in a time series, and making it possible to detect fires with high accuracy based on the observation data that accurately shows the changes in smoke density over time.

In addition, during normal monitoring conditions when the smoke density is below the threshold, the detection light is emitted intermittently, and the occurrence frequency of a state in which the smoke density satisfies the specified threshold condition and the detection light is emitted continuously is extremely low and exceptional. Therefore, when considering the overall operating period, the current consumption required to emit the detection light can be reduced to approximately the same as when only the detection light is emitted intermittently.

(Effect of fire detection by the detection unit)
In addition, the detection unit detects specified features from multiple consecutive smoke densities in a time series contained in the observation data, and detects a fire if the features satisfy specified fire judgment conditions, thereby enabling more accurate fire detection.

(Effect of fire detection based on features)
The detection unit determines that there is a fire when the feature quantity detected at predetermined time intervals based on the observation data, the ratio between the current feature quantity and the previous feature quantity, or the difference between the current feature quantity and the previous feature quantity each satisfy a predetermined fire determination condition, for example, when it is above or exceeds a predetermined threshold value, or when it is above or exceeds a predetermined threshold value a predetermined number of times consecutively, thereby enabling more accurate fire detection by making a judgment that captures the feature quantity of the temporal change in smoke concentration that is specific to a fire.

(Effect of features)
In addition, the detection unit detects integral values, average values or peak values from multiple consecutive smoke concentrations in a time series contained in the observation data to obtain a single feature, enabling highly accurate fire detection through simple processing.

(Effects of Disaster Prevention Equipment 1)
The present invention is a disaster prevention equipment that uses the above-mentioned fire detection device, and by providing the sensor with all of the observation section, processing section, and detection section, it is possible to deal with the problem by simply making changes to the sensor.Even in the case of existing equipment, it can be easily dealt with by removing the sensor mounted on the base and replacing it with a sensor equipped with all of the observation section, processing section, and detection section.

(Effects of Disaster Prevention Equipment 2)
The present invention is a disaster prevention equipment that uses the above-mentioned fire detection device, and by providing an observation unit and a processing unit in the sensor and a detection unit in the receiver, it is possible to reduce the number of modifications required on the sensor side and to reduce the cost of the equipment as a whole.

(Effects of Fire Detection Methods 1 and 2)
The present invention, as a fire detection method, provides the same effects as those of the fire detection devices 1 and 2 described above.

1 is an explanatory diagram showing the basic concept of a fire detection device, a disaster prevention equipment, and a fire detection method according to the present invention. FIG. 2 is an explanatory diagram of a disaster prevention facility showing a specific embodiment of the present invention targeted at a P-type disaster prevention facility corresponding to FIG. 1. 3 is a flow chart illustrating a control operation according to an embodiment of the sensor of FIG. 2 . 1 is an explanatory diagram showing another basic concept of the fire detection device, disaster prevention equipment, and fire detection method of the present invention, which judges a fire on the receiver side. FIG. 5 is an explanatory diagram of a disaster prevention facility showing a specific embodiment of the present invention targeted at an R-type disaster prevention facility corresponding to FIG. 4. 6 is a flowchart showing a control operation according to the embodiment of the R-type disaster prevention equipment of FIG. 5 in the form of a time chart.

Below, embodiments of a fire detection device, disaster prevention equipment, and fire detection method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments.

[Basic Concept of the Embodiment]
Fig. 1 is an explanatory diagram showing the basic concept of an embodiment of the present invention corresponding to a disaster prevention facility 1, and the basic concept of the embodiment will be described with reference to Fig. 1. This embodiment generally relates to a fire detection device, a disaster prevention facility, and a fire detection method. Note that an embodiment corresponding to a disaster prevention facility 2 will be described separately.

A "fire detection device" is a means for detecting fires in a monitored area, and is a concept that includes, for example, smoke detectors, fire detectors, fire alarms, etc.

Here, the "monitored area" refers to the area that is monitored by the fire detection device, and is an outdoor or indoor space with a certain extent, and is a concept that includes spaces such as rooms, corridors, and staircases of a building.

The fire detection device is, as an example, a disaster prevention equipment sensor 12 that is composed of a receiver 10 and a sensor 12, and has an observation unit 16, a processing unit 18, and a detection unit 20.

The "observation unit 16" observes smoke density by receiving scattered or attenuated light generated by irradiating smoke that has flowed into the smoke detection space from a specified monitoring area with detection light. Here, the "smoke detection space" refers to a space for detecting smoke in which smoke from the outside flows in but the incidence of light is blocked, in which a light-emitting element and a light-receiving element are installed, and the smoke density is observed by receiving the scattered or attenuated light generated when the detection light from the light-emitting element is irradiated onto the flowing smoke, and is a concept that includes a scattering type smoke detection unit or a light-reducing type smoke detection unit.

The "processing unit 18" is a unit that, when the smoke density observed by intermittently emitting the detection light satisfies a predetermined threshold condition, for example, when the smoke density is equal to or exceeds the threshold, continuously emits the detection light to observe the smoke density, and generates observation data including a plurality of observation values obtained continuously in a time series for each predetermined time. Here, "intermittent emission" means that the detection light is intermittently emitted by driving the light-emitting element to emit light for a predetermined time at a predetermined cycle. Furthermore, "continuous emission" means that the detection light is continuously emitted by continuing to drive the light-emitting element. Furthermore, "observation data including a plurality of observation values obtained continuously in a time series for each predetermined time" is a concept including time series data including a plurality of digital observation values (digital smoke density) obtained by sampling analog observation values (analog smoke density) continuously observed for a predetermined time at a predetermined frequency and A/D converting the analog observation values (analog smoke density) when the detection light is continuously emitted. Furthermore, the processing unit 18 may always emit the detection light continuously without switching from intermittent emission to continuous emission.

The "detection unit 20" performs processing to detect fires based on the observation data generated by the processing unit 18, for example by detecting a predetermined feature value from multiple observation values included in the observation data, and detecting a fire when the feature value satisfies a predetermined fire judgment condition.

Here, "feature amount" is a concept that includes, for example, an integral value, an average value, or a peak value calculated from multiple observation values included in the observation data. Also, "the feature amount satisfies a specified fire determination condition" is a concept that includes, for example, determining that a fire has occurred when a feature amount detected at a specified time interval based on the observation data, the ratio between the current feature amount and the previous feature amount, or the difference between the current feature amount and the previous feature amount, is equal to or exceeds a specified threshold value, or is equal to or exceeds a specified threshold value a specified number of times in succession.

In the following explanation, we will explain the case where the "monitoring area" is a "room in a building," the "observation unit" is an "observation unit equipped with a scattered light smoke detection unit," the "smoke observation value" is "smoke concentration," and the "feature value of the observation data" is the "integral value of multiple smoke concentrations."

[Specific Contents of the Embodiment]
The specific contents of the embodiments of the fire detection device, the disaster prevention equipment, and the fire detection method will be described in more detail below. The contents will be described separately as follows.
a. P-type disaster prevention equipment b. Receiver c. Sensor c1. Observation unit c2. Processing unit c3. Detection unit c4. Control operation of the sensor d. Basic concept of other embodiments e. R-type disaster prevention equipment e1. Sensor e2. Receiver e3. Transmission control e4. Control operation of the R-type disaster prevention equipment f. Modification of the present invention

[a. P-type disaster prevention equipment]
Fig. 2 is an explanatory diagram showing a specific embodiment of the present invention targeted at a proprietary-type (P-type) disaster prevention facility corresponding to Fig. 1. Here, the "P-type disaster prevention facility" is a facility in which a receiver 10 monitors fires for each signal line (for each signal line) to which a detector 12 is connected.

As shown in FIG. 2, the P-type disaster prevention equipment of this embodiment includes a receiver 10 and multiple sensors 12. Note that FIG. 2 shows one sensor 12 as a representative. The receiver 10 is installed in a manager's office, a disaster prevention center, etc., and multiple sensors 12 are connected to a signal line 14 that is drawn from the receiver 10 to a monitoring area such as a room in a building. The signal line 14 drawn from the receiver 10 includes a positive signal line 14a and a negative signal line (common signal line) 14b, and supplies power from the receiver 10 to the sensors 12 and transmits a fire alert signal from the sensor 12 to the receiver 10.

[b. Receiver]
The receiver 10 comprises a receiver control unit 40, a line receiving unit 42, a display unit 44, an operation unit 46, an alarm unit 48, and a report transmission unit 50. The line receiving units 42 are provided for each signal line 14 drawn out in a monitored area, for example, for each floor of a building, and receive fire alert signals from the detectors 12 and output them to the receiver control unit 40.

The receiver control unit 40 is composed of a computer circuit equipped with a CPU, memory, and various input/output ports, and performs a fire alarm operation when it detects the reception of a fire alert signal (fire signal) by any of the line receiving units 42. The fire alarm operation of the receiver control unit 40 activates the fire representative light on the display unit 44 and the district indicator light indicating the district where the fire occurred, outputs a main sound alarm including an alarm voice message by the alarm unit 48, and performs a district sound alarm by activating a district sounding device installed in the monitoring area where the fire occurred, and also instructs the reporting unit 50 to perform interlocking control of smoke control equipment, etc.

[c. Sensor]
The configuration of the sensor 12 that functions as a fire detection device will be described in more detail. The sensor 12 includes an observation section 16, a sensor control section 24, an alarm circuit section 26, and a power supply section 28, which are components of the fire detection device. The observation section 16 includes a smoke detection section 25, a light emission drive section 34, and a light receiving amplifier section 36. The sensor control section 24 is formed of a computer circuit including a CPU, memory, and various input/output ports, and is provided with the functions of a processing section 18 and a detection section 20, which are components of the fire detection device, as functions realized by executing a program.

(c1. Observation section)
The smoke detection section 25 provided in the observation section 16 constitutes a scattered light type smoke detection section, in which a light emitting element 30 and a light receiving element 32 are arranged in a smoke detection space inside the light-shielded sensor into which smoke from the outside flows in, so that their optical axes intersect at a scattering angle that is a predetermined acute angle, the area including the intersection of the optical axes is the smoke detection area, and the light receiving element 32 receives so-called forward scattered light, which is scattered when detection light is irradiated from the light emitting element 30 to smoke that has flowed into the smoke detection area. The scattering angle is arbitrary, and it is also possible to receive backward scattered light by setting the scattering angle to a predetermined obtuse angle exceeding a right angle.

The light-emitting element 30 is, for example, a light-emitting diode, but may be any light-emitting element, and the light-receiving element 32 is, for example, a photodiode, but may be any light-receiving element. The light-emitting element 30 is driven to emit light by the light-emitting drive unit 34, and irradiates the smoke detection area with detection light. The light-receiving element 32 receives the scattered light of smoke caused by the detection light, and outputs a light-receiving current of, for example, 1 to 10 μA depending on the amount of scattered light received. The light-receiving amplifier unit 36 inputs and amplifies the light-receiving current from the light-receiving element 32, and outputs a light-receiving voltage of, for example, 1 to 5 mV, and this light-receiving voltage corresponds to the smoke concentration.

(c2. Processing section)
The processing unit 18 emits the detection light of the observation unit 16 intermittently at a predetermined cycle, and when a predetermined threshold condition observed is satisfied, for example when the smoke density is equal to or exceeds a predetermined threshold, the processing unit 18 continuously emits the detection light to observe the smoke density, and generates observation data including a plurality of observation values obtained continuously in a time series at predetermined time intervals, specifically, in the following procedure.

First, when the smoke density is less than a predetermined threshold fire warning level (preliminary fire judgment level), for example 3 (%/m), the processing unit 18 emits detection light intermittently to observe the smoke density. In this case, the period of the intermittent emission is set to, for example, a one-minute period in order to reduce the current consumption of the detector 12. That is, the processing unit 18 outputs a pulse drive signal of about several pulses with a period on the order of microseconds from the light emission drive unit 34 to the light emitting element 30 every one minute period to perform intermittent emission of detection light that drives the light emission in a pulsed manner, and reads the smoke density detection signal (analog signal) output from the light receiving amplifier unit 36 in association with this intermittent emission by A/D conversion synchronized with the pulse emission, and obtains the average smoke density as the observed value.

Secondly, when the smoke density observed by the intermittent emission of the detection light reaches a fire warning level that is a predetermined threshold, for example, 3 (%/m) or more, the processing unit 18 continuously inputs a drive signal of a constant level to the light emission driving unit 34, drives the light emitting element 30 to a constantly on state to continuously output the detection light, samples the smoke density detection signal (analog signal) output from the light receiving amplifier unit 36 at a predetermined sampling frequency and performs A/D conversion, and generates multiple observation values that are consecutive in time series, i.e., observation data including multiple smoke densities, every predetermined time, for example every 2 seconds, and stores and holds them in memory.

If the sampling frequency of the A/D conversion is, for example, 16 Hz, observation data containing 32 points of smoke concentration are generated in 2 seconds. Here, the predetermined time for generating the observation data and the sampling frequency are arbitrary, and the predetermined time for generating the observation data is a time sufficient to capture the temporal changes in smoke specific to a fire, and the sampling frequency is set to a time interval (sampling period) that does not lose any changes in smoke concentration due to a fire.

The continuous emission of detection light may be achieved by inputting a continuous pulse signal at the sampling frequency used for A/D conversion of the observation data to the light emission driver 34 to continuously pulse drive the light emitting element 30.

(c3. Detection unit)
The detection unit 20 provided in the sensor control unit 24 detects a fire based on the observation data generated by the processing unit 18, and may have any function or configuration, but may, for example, detect a predetermined feature, such as an integral value of multiple smoke densities that are consecutive in time series contained in the observation data, and detect a fire when this integral value satisfies a predetermined fire judgment condition. Here, the integral value of multiple smoke densities means a value obtained by accumulating multiple smoke densities. The fire judgment conditions for detecting a fire by the detection unit 20 are arbitrary, and examples are listed below.

(First fire judgment condition)
The detection unit 20 determines that a fire has occurred when an integrated value of the smoke density detected at each predetermined time interval is equal to or exceeds a predetermined threshold value.

(Second fire judgment condition)
The detection unit 20 judges that a fire has occurred when the integrated value of the smoke density detected at each predetermined time interval is equal to or exceeds a predetermined threshold value a predetermined number of times in succession. It is an addition.

(Third fire judgment condition)
The detection unit 20 determines that a fire has occurred when the ratio of the current integrated value of the smoke density to the previous integrated value of the smoke density detected at each predetermined time is equal to or exceeds a predetermined threshold value. Judge.

(Fourth fire judgment condition)
The detection unit 20 detects whether a ratio of an integrated value of a current smoke density to an integrated value of a previous smoke density is equal to or greater than a predetermined threshold value a predetermined number of times in succession, for an integrated value of a smoke density detected at a predetermined time interval. This is the third fire detection condition plus an accumulation condition.

(Fifth fire judgment condition)
The detection unit 20 determines that a fire has occurred when the difference between the current integrated value of the smoke density and the previous integrated value of the smoke density detected at each predetermined time is equal to or exceeds a predetermined threshold value. Judge.

(6th fire judgment condition)
The detection unit 20 detects whether a difference between a current integrated value of the smoke density and a previous integrated value of the smoke density detected at every predetermined time is equal to or greater than a predetermined threshold value a predetermined number of times in succession. This is the fifth fire detection criterion plus an accumulation condition.

For these first to sixth fire judgment conditions, the detection unit 20 judges that a fire has occurred when the integrated value of the smoke concentration detected as a feature of the observation data satisfies any one of the fire judgment conditions or a combination of multiple fire judgment conditions.

In addition, the detection unit 20 may detect, as a feature of the observation data, for example, the average value or peak value of the smoke density in addition to the integrated value of the smoke density, and may determine that a fire has occurred in the same manner as the first to sixth fire determination conditions described above.

Here, since the detector 12 is legally required to have a class 1, class 2, or class 3 sensitivity, the thresholds of the features in the first to sixth fire judgment conditions can be determined to satisfy the operation test and the deactivation test at each sensitivity.

For example, a "class 2 sensitivity detector" refers to a detector with a legally stipulated nominal activation concentration K of 10 (%/m), which activates within 30 seconds when placed in an airflow with a wind speed of 20 cm to 40 cm/sec containing smoke with a concentration of (nominal activation concentration K) x 1.5 = 10 (%/m) x 1.5 = 15 (%/m) as an activation test, and does not activate within 5 minutes, for example in the case of a non-accumulation type, when placed in an airflow with a wind speed of 20 cm to 40 cm/sec containing smoke with a concentration of (nominal activation concentration) x 0.5 = 10 (%/m) x 0.5 = 5 (%/m) as a non-activation test. Therefore, by setting the thresholds of the feature quantities in the first to sixth fire judgment conditions so as to satisfy the activation test and the non-activation test, the detector 12 equipped with the fire detection device of this embodiment can be realized as a certified product with class 2 sensitivity.

In addition to these second-sensitivity detectors with a nominal operating concentration K = 10 (%/m), the same applies to "first-sensitivity detectors" with a nominal operating concentration K = 5 (%/m) and "third-sensitivity detectors" with a nominal operating sensitivity K = 15 (%/m).

(c4. Sensor control operation)
FIG. 3 is a flow chart showing the control operation according to the embodiment of the sensor of FIG. 2, which is controlled by the processing unit 18 and the detection unit 20 provided in the sensor control unit 24.

As shown in FIG. 3, the processing unit 18 emits detection light intermittently at a predetermined cycle, for example, every minute, in step S1, and observes the smoke concentration based on the reception of scattered light in step S2. That is, the light-emitting element 30 is driven to emit detection light intermittently by the light-emitting drive unit 34, and scattered light caused by smoke or the like is received by the light-receiving element 32. The smoke concentration detection signal amplified by the light-receiving amplifier unit 36 is read in by A/D conversion synchronized with the intermittent emission to observe the smoke concentration.

Then, the processing unit 18 compares the smoke density due to the intermittent light emission observed in step S3 with a fire warning level, which is a predetermined threshold. If the fire warning level is exceeded, the processing proceeds to step S4, switches to continuous emission of detection light, and generates observation data for each predetermined time in step S5. That is, the light-emitting element 30 is continuously driven to emit detection light by the light-emitting element driving unit 34, and scattered light due to smoke or the like is received by the light-receiving element 32. The smoke density detection signal amplified by the light-receiving amplifier unit 36 is sampled at a predetermined sampling frequency, for example, a sampling frequency of 16 Hz, and A/D converted. Smoke density at successive points in time series, for example, 32 points, is read every predetermined time, for example, every 2 seconds, to generate observation data, which is then stored and held in memory.

Then, the detection unit 20 proceeds to step S6, where it detects a predetermined feature, for example, an integrated value (cumulative value) of the 32 smoke densities included in the observation data generated in step S5. The detection unit 20 then proceeds to step S7, where it determines whether the feature detected in step S6, for example, the integrated value of the 32 smoke densities, satisfies a predetermined fire judgment condition, and if it determines that the fire condition is satisfied, it proceeds to step S8, where it activates the alarm circuit unit 26 to transmit a fire alarm signal to the receiver 10.

Next, in step S9, the sensor control unit 24 determines whether recovery has occurred based on the interruption of the power supply to the signal line 14 associated with the recovery operation on the receiver 10, and returns to the initial sensor control in step S1.

On the other hand, if the feature does not satisfy the fire judgment condition in step S7, the detection unit 20 proceeds to step S10, for example, extracts the peak value of the smoke density in the observation data at that time, and if the peak value exceeds the fire warning level, repeats the processing from step S4, but if it is below the fire warning level, the possibility of a fire has disappeared, so the process returns to step S1 and returns to the normal monitoring state in which the smoke density is observed by the intermittent emission of the detection light. Note that in step S10, the average value of the observation data may be calculated and compared with the fire warning level.

[d. Basic Concept of Other Embodiments]
Figure 4 is an explanatory diagram showing another basic concept of an embodiment of a fire detection device, disaster prevention equipment, and fire detection method corresponding to the disaster prevention equipment 2, and is a fire alarm system as an example of disaster prevention equipment equipped with a receiver 10 and a sensor 12, characterized in that the sensor 12 is provided with an observation unit 16 and a processing unit 18 which are components of the fire detection device, and the receiver 10 is provided with a detection unit 20 which is a component of the fire detection device.

The observation unit 16 and processing unit 18 provided in the detector 12, and the detection unit 20 provided in the receiver 10 are basically the same as the observation unit 16, processing unit 18, and detection unit 20 provided in the detector 12 in FIG. 1, but differ in that observation data including multiple observation values for a predetermined time period observed by the continuous light emission of the observation unit 16 generated by the processing unit 18 of the detector 12 is transmitted to the receiver 10 via the signal line 14, the detection unit 20 of the receiver 10 detects multiple smoke concentration features included in the observation data, and when the detected features satisfy predetermined fire judgment conditions, a fire is detected and a fire alarm is output.

Next, we will explain in more detail the specific content of the embodiment corresponding to Figure 4.

[e. R-type disaster prevention equipment]
Fig. 5 is an explanatory diagram of an R-type (Record-type) disaster prevention system showing specific details of an embodiment corresponding to Fig. 4. Here, the "R-type disaster prevention system" is a system that monitors fires for each sensor 12 (sensor unit) by transmitting between a receiver 10 and a sensor 12.

As shown in FIG. 5, the R-type disaster prevention equipment of this embodiment includes a receiver 10 and sensors 12, with multiple sensors 12 connected to a transmission line 114 drawn from the receiver 10 to a monitoring area such as a room in a building. The transmission line 114 drawn from the receiver 10 includes a positive transmission line 114a and a negative transmission line (common transmission line) 114b, and supplies power from the receiver 10 to the sensors 12, as well as transmitting and receiving signals between the receiver 10 and the sensors 12 using a specified transmission method. A dedicated power supply line may also be provided.

(e1. Sensor)
2, the sensor 12 includes an observation unit 16, a sensor control unit 24, and a power supply unit 28, which are components of a fire detection device, but differs in that a transmission unit 60 is provided to transmit and receive signals to and from the receiver 10 using a predetermined transmission method. Also, the sensor control unit 24 of the sensor 12 is provided with the functions of the processing unit 18, which are components of the fire detection device of the present invention, but is not provided with the functions of the detection unit 20, which are provided on the receiver 10 side.

(e2. Receiver)
2, the receiver 10 includes a receiver control unit 40, a display unit 44, an operation unit 46, an alarm unit 48, and a reporting unit 50, but differs in that a transmission unit 62 is provided to transmit and receive signals to and from the detector 12 using a predetermined transmission method, and in that the receiver control unit 40 is provided with the function of a detection unit 20, which is a component of the fire detection device of the present invention, as a function realized by executing a program. The detection unit 20 provided in the receiver 10 is basically the same as that provided in the detector 12 in the embodiment of FIG. 2.

(e3. Transmission Control)
In the R-type disaster prevention equipment, a unique address is set for each detector 12, and the receiver 10 transmits a batch A/D conversion command signal at a predetermined cycle, for example, at one-minute cycles. When all detectors 12 receive the batch A/D conversion command signal from the receiver 12, the processing unit 18 performs processing to observe the smoke density by intermittent light emission in the observation unit 16, A/D converts the smoke density observed by the intermittent light emission, and stores it. Following the batch A/D command signal, the receiver 10 transmits a call signal that sequentially specifies the detector addresses, and performs polling to have each detector 12 return a response signal including the smoke density observed.

When the smoke density observed by the intermittent light emission reaches a predetermined threshold fire warning level, for example 3 (%/m), the processing unit 18 of the detector 12 determines that there is a fire warning and transmits a fire interrupt signal to the receiver 10. Also, when the detector 12 determines that there is a fire warning, it switches the observation unit 16 to observing the smoke density by continuous light emission, and accordingly the processing unit 18 performs A/D conversion at a predetermined sampling frequency every predetermined time, for example every 2 seconds, to generate and store observation data including multiple observation values that are consecutive in time series.

When the receiver 10 receives a fire interrupt signal from a detector 12, it transmits a group search command signal specifying a group address, performs a group search to identify the group address to which the detector 12 that responded with the fire interrupt signal belongs, and then transmits an intra-group search command signal sequentially specifying the detector addresses within the searched group address, to identify the address of the detector 12 that responded with the fire interrupt signal, i.e., the detector 12 that has been determined to be a fire precursor.

Then, the receiver 10 transmits a call signal specifying the address of the detector 12 that has been determined to be a fire warning signal, for example at a 2-second interval based on the transmission of the A/D conversion command signal at a 1-minute interval, acquires observation data from the detector 12 that has been determined to be a fire warning signal, detects features from the observation data using the detection unit 20 provided in the receiver control unit 40, and detects a fire if the detected features satisfy a predetermined fire judgment condition, and outputs a fire alarm.

(e4. Control operation of R-type disaster prevention equipment)
FIG. 6 is a flow chart showing, in the form of a time chart, the control operation of the embodiment of the R-type disaster prevention equipment of FIG.

As shown in FIG. 6, in step S11, the receiver 10 transmits a batch A/D conversion command signal at a predetermined cycle, for example, one minute, as a fire monitoring transmission process, then transmits a call signal specifying the detector address, and receives a response signal including the smoke density observed from the detector 12. Meanwhile, when the detector 12 receives the batch A/D conversion command signal from the receiver 10 as a fire monitoring response process in step S12, the processing unit 18 observes and stores the smoke density at that time by the intermittent light emission of the observation unit 16, then receives a call signal specifying its own address to be received, and transmits a response signal including the smoke density.

Next, in step S13, if the detector 12 determines that the smoke concentration observed by the intermittent emission has reached a predetermined threshold fire warning level, for example 3 (%/m), the process proceeds to step S14, where the detector 12 transmits a fire interrupt signal to the receiver 10 as a fire warning transmission process. In step S15, the receiver 10 searches for and identifies the address of the detector that transmitted the fire interrupt signal based on the reception of the fire interrupt signal from the detector 12 as a fire warning reception process.

Then, in step S16, the processing unit 18 of the detector 12 switches the observation unit 16 to continuous light emission to observe the smoke concentration, and in step S17, every predetermined time period, for example every 2 seconds, the detector 12 generates and stores observation data containing multiple consecutive smoke concentrations in a time series by A/D conversion at a predetermined sampling frequency.

Then, in step S19, the receiver 10 performs an observation data reception process in which it repeatedly transmits a call signal specifying the address of the detector 12 that transmitted the fire interrupt signal, at a cycle of, for example, 2 seconds, which is shorter than the transmission cycle of the batch A/D command signal, and causes the detector 12 to perform an observation data transmission process in which it transmits the observation data stored in memory in step S18, thereby intensively receiving observation data from the detectors 12 that it has determined to be a sign of a fire.

Then, the receiver 10 proceeds to step S20, and if it determines that observation data has been received, it proceeds to step S21, where it detects features from the multiple smoke densities contained in the observation data, and in step S22 detects a fire if the features satisfy a predetermined fire judgment condition, and in step S23 performs fire alarm processing including sounding a main acoustic alarm and a district acoustic alarm, displaying the location of the fire based on the address of the detector that has judged it to be a fire, and controlling the linkage of smoke control and exhaust equipment.

Next, if the receiver 10 determines in step S24 that recovery has been performed as a result of a recovery operation following the extinguishing of the fire, it transmits a recovery signal to the detector 12 in step S25 and returns to the fire monitoring transmission process in step S11. Also, if the detector 12 determines in step S27 that it has received a recovery signal, it returns to the fire monitoring response process in step S12.

Meanwhile, the detector 12 proceeds to step S26 after performing the observation data transmission process in step S18, and if the smoke density observed by the continuous light emission of the observation unit 16 is equal to or higher than the fire warning level, which is a predetermined threshold, the process repeats from step S17 via step S27. However, if the smoke density falls below the fire warning level, the process returns to step S12, and returns to the normal monitoring state in which the smoke density is observed by intermittently emitting light upon receiving a batch A/D conversion command signal from the receiver 10. In step S26, for example, a peak value is extracted from the multiple smoke densities included in the observation data generated in step S17, or an average value is calculated, and it is determined whether or not the smoke density is below the fire warning level.

In the R-type disaster prevention equipment described above, a detection unit 20 is provided in the receiver 10, which detects features from multiple smoke densities contained in the observation data received from the detector 12, and detects a fire when the features satisfy a specified fire judgment condition; however, a function for detecting features from the observation data in the detection unit 20 may be provided on the detector 12 side, and the detector 12 may detect features from the observation data and transmit them to the receiver 10, and a fire may be detected when the features received on the receiver 10 satisfy the fire judgment condition. This can reduce the amount of data transmitted from the detector 12 to the receiver 10.

[f. Modifications of the present invention]
An alternative embodiment of the invention will now be described in more detail.

(Switching between intermittent and continuous lighting)
In the above embodiment, intermittent emission is switched to continuous emission when the smoke density reaches or exceeds a predetermined threshold fire warning level; however, the conditions and timing for switching between intermittent emission and continuous emission are arbitrary, and for example, a switching command signal from the receiver may be used to switch from intermittent emission to continuous emission as necessary, or from continuous emission to intermittent emission.

(Fire detection device that emits continuous light at all times)
In the above embodiment, when the smoke density reaches or exceeds a predetermined threshold fire warning level, intermittent emission is switched to continuous emission, but the fire detection device may also be configured not to switch between intermittent and continuous emission, but to always emit detection light continuously to observe the smoke density, generate observation data including multiple observation values obtained continuously in a time series at predetermined time intervals, and detect fires based on the observation data.

(Dimmable smoke detector)
The above embodiment is an example of a light scattering type smoke detector, but is not limited thereto. For example, a light-dimming type smoke detector may be used. The light-dimming type smoke detector is provided with a known light-dimming type smoke detector structure in which light from a light-emitting unit is reflected by a plurality of mirrors arranged in a circular ring shape in a smoke detection space, and the optical path length to the light-receiving unit is made long enough to obtain sufficient light dimming due to smoke. In addition, the smoke detector may be provided with a known composite smoke detector structure that is provided with a light-scattering type smoke detector structure and a light-dimming type smoke detector structure in one body.

(Two-wavelength smoke detector)
The scattered light smoke detector of the above embodiment may be a two-wavelength smoke detector that receives scattered light due to differences in scattering characteristics of light of different wavelengths to identify the type of smoke. The two-wavelength smoke detector emits light of a first wavelength and a second wavelength toward a smoke detection space from a light-emitting element using a white light-emitting diode or from first and second light-emitting elements with different emission wavelengths, and provides a first light-receiving element sensitive to light of the first wavelength and a second light-receiving element sensitive to light of the second wavelength at positions of different crossing angles that do not directly receive the light emitted from the light-emitting element, and identifies the type of smoke by comparing the light-receiving output of the smoke scattered light due to a small confusion angle caused by the light of the first wavelength received by the first light-receiving element with the light-receiving output of the smoke scattered light due to a large scattering angle received by the second light-receiving element, and performs a fire judgment according to a judgment criterion according to the type of smoke.

In this case, too, in the normal monitoring state, current consumption is reduced by observing smoke density through intermittent light emission, but when the smoke density observed through intermittent light emission exceeds a predetermined threshold, the system switches to observing smoke density through continuous light emission, generating observation data containing multiple smoke densities that are consecutive in time series for a predetermined period of time, detecting features from the multiple smoke densities contained in the observation data, and detecting a fire when the features satisfy the fire judgment conditions.

(Fire alarm)
The above embodiment has been described as an example of a fire detection device for disaster prevention equipment equipped with a receiver and a sensor, but a fire detection device may also be configured as, for example, a residential fire alarm equipped with a means for observing smoke density to determine whether a fire has occurred and a means for issuing a fire alarm. In the case of a fire alarm, the functions of the observation unit 16, processing unit 18, and detection unit 20 constituting the fire detection device of the present invention are provided in the fire alarm, similar to the sensor 12 of the disaster prevention equipment shown in Figures 1 and 2.

(others)
Furthermore, the present invention includes appropriate modifications that do not impair the objects and advantages of the present invention, and is not limited to the numerical values shown in the above embodiment.

10: Receiver 12: Sensor 14: Signal line 16: Observation section 18: Processing section 20: Detection section 24: Sensor control section 25: Smoke detection section 26: Alarm circuit section 28: Power supply section 30: Light emitting element 32: Light receiving element 34: Light emitting drive section 36: Light receiving amplifier section 40: Receiver control section 42: Line receiving section 44: Display section 46: Operation section 48: Alarm section 50: Reporting section 60, 62: Transmission section 114: Transmission line

Claims (15)

an observation unit that irradiates smoke that has flowed into a smoke detection space from a predetermined monitoring area with a detection light and receives scattered light or attenuated light generated to observe smoke concentration;
a processing unit that continuously emits the detection light to observe the smoke concentration and generates observation data including a plurality of observation values obtained continuously in a time series at predetermined intervals;
A detection unit that detects a fire based on the observation data;
A fire detection device comprising:
an observation unit that irradiates smoke that has flowed into a smoke detection space from a predetermined monitoring area with a detection light and receives scattered light or attenuated light generated to observe smoke concentration;
a processing unit that, when the smoke density observed by intermittently emitting the detection light at a predetermined cycle satisfies a predetermined threshold condition, continuously emits the detection light to observe the smoke density, and generates observation data including a plurality of observation values obtained continuously in a time series for each predetermined time period;
A detection unit that detects a fire based on the observation data;
A fire detection device comprising:
The fire detection device according to claim 1 or 2,
The detection unit is
detecting a predetermined feature value from a plurality of the observation values included in the observation data, and detecting a fire when the feature value satisfies a predetermined fire determination condition;
A fire detection device comprising:
The fire detection device according to claim 3,
The detection unit determines that a fire has occurred when the feature amount detected at each predetermined time is equal to or exceeds a predetermined threshold value.
A fire detection device comprising:
The fire detection device according to claim 3,
The detection unit determines that a fire has occurred when the feature amount detected at each predetermined time interval is equal to or exceeds a predetermined threshold value a predetermined number of times in succession.
A fire detection device comprising:
The fire detection device according to claim 3,
The detection unit determines that a fire has occurred when a ratio of a current feature amount to a previous feature amount detected at each predetermined time interval is equal to or exceeds a predetermined threshold value.
A fire detection device comprising:
The fire detection device according to claim 3,
the detection unit determines that a fire has occurred when a ratio of a current feature amount to a previous feature amount detected at each predetermined time interval is equal to or exceeds a predetermined threshold value for a predetermined number of consecutive times;
A fire detection device comprising:
The fire detection device according to claim 3,
The detection unit determines that a fire has occurred when a difference between a current feature amount and a previous feature amount detected at each predetermined time interval is equal to or greater than a predetermined threshold value.
A fire detection device comprising:
The fire detection device according to claim 3,
the detection unit determines that a fire has occurred when a difference between a current feature amount and a previous feature amount detected at each predetermined time interval is equal to or exceeds a predetermined threshold value a predetermined number of times in succession,
A fire detection device comprising:
The fire detection device according to any one of claims 1 to 9,
The fire detection device is characterized in that the detection unit detects an integral value, an average value, or a peak value of a plurality of observation values contained in the observation data as a feature of the observation data.
A disaster prevention facility using the fire detection device according to any one of claims 1 to 10,
a receiver and a detector that detects a fire and transmits a fire signal to the receiver;
A disaster prevention system comprising the sensor, the observation unit, the processing unit, and the detection unit.
A disaster prevention facility using the fire detection device according to any one of claims 1 to 10,
a receiver and a detector that detects a fire and transmits a fire signal to the receiver;
The sensor is provided with the observation unit and the processing unit,
A disaster prevention system comprising the receiver and the detection unit.
The observation unit irradiates the smoke that has flowed into the smoke detection space from the predetermined monitoring area with the detection light, receives the scattered light or attenuated light generated, and observes the smoke concentration;
A processing unit continuously emits the detection light to observe the smoke concentration, and generates observation data including a plurality of observation values obtained continuously in a time series for each predetermined time period;
A detection unit detects a fire based on the observation data.
A fire detection method comprising:
The observation unit irradiates the smoke that has flowed into the smoke detection space from the predetermined monitoring area with the detection light, receives the scattered light or attenuated light generated, and observes the smoke concentration;
a processing unit that, when the smoke density observed by intermittently emitting the detection light at a predetermined cycle satisfies a predetermined threshold condition, continuously emits the detection light to observe the smoke density, and generates observation data including a plurality of observation values obtained continuously in a time series for each predetermined time period;
A detection unit detects a fire based on the observation data.
A fire detection method comprising:
The fire detection method according to claim 13 or 14, further comprising:
The detection unit is
detecting a predetermined feature value from a plurality of the observation values included in the observation data, and detecting a fire when the feature value satisfies a predetermined fire determination condition;
A fire detection method comprising:

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