Fire detection device, disaster prevention equipment, and fire detection method

Abstract

To provide a fire detection device capable of quickly and appropriately detecting a fire in accordance with the identified kind of smoke, a disaster prevention facility, and a fire detection method.SOLUTION: In a disaster prevention facility, a signal detection unit 16 of a sensor 12 detects a first signal and a second signal by a first optical setting of a first wavelength and a first diffusion angle and a second optical setting of a second wavelength and a second diffusion angle, as a signal associated with an optical action such as diffusion due to a detection object such as smoke or steam in a monitored area. An identification unit 18 identifies a type of the detection object such as white smoke, black smoke, and steam, or a factor of occurrence on the basis of a ratio of the first and second signals or the like. A fire detection unit 20 detects a fire in a case where predetermined fire detection conditions are satisfied on the basis of at least one of the first and second signals. In addition, the fire detection conditions are changed in accordance with an identification result, such as white smoke, black smoke, and steam, made by the identification unit 18.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fire detection device such as a smoke detector that detects a fire from the optical effect of smoke, a disaster prevention facility, and a fire detection method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, fire detection devices such as smoke detectors that receive scattered light with different scattering angles and different wavelengths to identify the type of smoke are known.

[0003] For example, by varying the scattering angle of two light-emitting elements relative to the light-receiving element, differences in scattered light depending on the type of smoke can be created, and at the same time, by varying the wavelength of the light emitted from the two light-emitting elements, differences in scattering characteristics due to wavelength can be created.The synergistic effect of these differences in scattering angle and wavelength creates a significant difference in the light intensity of the scattered light depending on the type of smoke, thereby increasing the accuracy of smoke identification and preventing false fire alarms caused by cooking steam, etc., and also making it possible to reliably identify the type of burning material, such as black smoke fires and white smoke fires, when it comes to smoke from fires. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-325211 [Patent Document 2] Japanese Patent Publication No. 2020-035029 [Patent Document 3] Japanese Patent Publication No. 2020-135263 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in such a conventional fire detection device for identifying the type of smoke, although it can distinguish, for example, a black smoke fire and a white smoke fire, there is room for improvement in terms of appropriate fire detection according to the type of smoke. That is, for example, in the case of a black smoke fire that is expected to spread more rapidly than a white smoke fire, it cannot be said to have sufficient performance in terms of detecting the fire more quickly and promptly outputting a fire signal.

[0006] An object of the present invention is to provide a fire detection device, a disaster prevention facility, and a fire detection method that enable rapid and appropriate fire detection according to the identified type of smoke.

Means for Solving the Problems

[0007] (Fire Detection Device) The present invention is a fire detection device, which detects a signal associated with the light action of a detection target in a monitoring area by at least a first optical setting and a second optical setting, and includes signal detection means for detecting a first signal obtained by the first optical setting and a second signal obtained by the second optical setting, identification means for identifying the type of the detection target or the type of the cause of occurrence of the detection target based on the first signal and the second signal detected by the signal detection means, fire detection means for detecting a fire when a predetermined fire detection condition is satisfied based on at least one of the first signal and the second signal detected by the signal detection means, and is characterized in that the fire detection condition is changed according to the identification result by the identification means.

[0008] Here, "identifying the type of the detection target based on the first signal and the second signal" includes, for example, identifying by comparing the first signal and the second signal, more specifically, for example, identifying based on the magnitude relationship between the first signal and the second signal, identifying based on the ratio between the first signal and the second signal, and the like.

[0009] (Optical Setting) ​The signal detection means Irradiates the detection target in the monitoring area with light of a first wavelength according to a first optical setting, and detects the received signal of the scattered light obtained at a first scattering angle as a first signal. Irradiates the detection target in the monitoring area with light of a second wavelength different from the first wavelength according to a second optical setting, and detects the received signal of the scattered light obtained at a second scattering angle different from the first scattering angle as a second signal.

[0010] (Identification of the detection target) The identification means identifies the type of the detection target as a fire detection target and a non-fire detection target. The fire detection conditions are 4]When the fire detection target is identified by the identification means, it is changed so that it is more likely to be detected as a fire by the fire detection means. Initial set fire detection conditions And when the non-fire detection target is identified by the identification means, it is changed so that it is less likely to be detected as a fire by the fire detection means. Initial set fire detection conditions

[0011] Here, the "fire detection target" refers to particles or the like that should be detected as a fire in the monitoring area, for example, smoke generated along with a fire. Examples of its types include white smoke (white-colored smoke) and black smoke (black-colored smoke). White smoke is, for example, whitish smoke generated by the smoldering (smoking) of wood, cloth, etc., and black smoke is, for example, blackish smoke generated by the ignition and burning of an object. As combustion materials for a fire model mainly accompanied by white smoke (white smoke fire), wood, cotton wicks, etc. are known, and as combustion materials for a fire model mainly accompanied by black smoke (black smoke fire), kerosene, etc. are known. Also, the "non-fire detection target" refers to particles or the like that should not be detected as a fire, and includes, for example, oil fumes, steam, vapor, dust, tobacco smoke, etc. generated by factors other than fire (non-fire factors). The generation factors for oil fumes, steam, and vapor that become non-fire detection targets include cooking, boiling water, using the bathroom, etc., the generation factors for dust include cleaning, sand and dust, etc., and the generation factor for tobacco is smoking.

[0012] ​​Here, "becoming more likely to detect a fire" means, for example, becoming such that a fire is detected under milder (relaxed) conditions, and thus, for example, a fire is detected earlier. Further, "becoming less likely to detect a fire" means, for example, becoming such that a fire is detected under stricter (strengthened) conditions, and thus, for example, a fire is detected later. That is, "changing the fire detection conditions" means relaxing the conditions for detecting a fire in the former case and strengthening the conditions for detecting a fire in the latter case.

[0013] (Discrimination between white smoke and black smoke) The discrimination means discriminates between white smoke and black smoke as fire detection targets, and the fire detection conditions are changed so that when white smoke is discriminated by the discrimination means, it becomes more likely to detect a fire by the fire detection means Initial set fire detection conditions than before, and when black smoke is discriminated by the discrimination means, it is changed so that it becomes more likely to detect a fire by the fire detection means than the fire detection conditions after the change associated with the discrimination of white smoke.

[0014] (Detection of increase rate) Furthermore, it is provided with an increase rate detection means for detecting the increase rate of at least one of the first signal and the second signal, and the fire detection conditions are changed based on the discrimination result by the discrimination means and the increase rate by the increase rate detection means.

[0015] (Change of fire detection conditions according to increase rate) The fire detection conditions are changed so that when the discrimination means discriminates the fire detection target as the type of the detection target and the increase rate by the increase rate detection means satisfies a predetermined increase rate threshold condition, it becomes more likely to detect a fire by the fire detection means than before the change.

[0016] (Change of fire detection conditions) The fire detection means is such that when at least one of the first signal and the second signal satisfies a predetermined threshold condition, or 、When at least one of the first signal and the second signal satisfies a predetermined threshold condition and a predetermined accumulation condition is satisfied to Fire and detection The fire detection conditions are: By making at least one of the threshold condition and the accumulation condition looser than before, It is now easier to detect fires than before the change. ri , By making at least one of the threshold condition and the accumulation condition stricter than before, It is now harder to detect as a fire than before the change. ru .

[0017] (First disaster prevention equipment) The present invention is a disaster prevention system using the above-mentioned fire detection device, a receiver and a detector that detects a fire and transmits a fire signal to the receiver; sensor is , a signal detection means, a discrimination means and a fire detection means, or a signal detection means, a discrimination means, a fire detection means and an increase rate detection means equipped It is characterized by the fact that

[0018] (Second disaster prevention equipment) The present invention is a disaster prevention system using the above-mentioned fire detection device, a receiver and a detector that detects a fire and transmits a fire signal to the receiver; sensor is , signal detection means equipped , Receiver is , identification means and fire detection means, or identification means, fire detection means and increase rate detection means equipped It is characterized by the fact that

[0019] (Fire detection method) The present invention provides a fire detection method for detecting a fire in a monitored area, comprising: The signal detection means detects a signal associated with an optical action of a detection target in a monitoring area using at least a first optical setting and a second optical setting, and detects a first signal obtained by the first optical setting and a second signal obtained by the second optical setting; Based on the first signal and the second signal detected by the signal detection means, the identification means identifies the type of detection target as a fire detection target and a non-fire detection target, and identifies white smoke and black smoke as the types of fire detection targets. When a predetermined fire detection condition is satisfied based on at least one of the first signal and the second signal detected by the signal detection means, the fire detection means detects a fire. The fire detection condition When white smoke is identified as a fire detection target by the identification means, it is changed so that it is easier to detect a fire than the fire detection condition initially set by the fire detection means. When black smoke is identified as a fire detection target by the identification means, it is changed so that it is easier to detect a fire than the fire detection condition after the change associated with the identification of white smoke by the fire detection means. When a non-fire detection target is identified by the identification means, the fire detection means Initial set fire detection conditions is changed so that it is more difficult to detect a fire.

[0020] (Detection of increase rate and change of fire detection condition) Fire detection method which are 、 The increase rate detection means detects the increase rate of at least one of the first signal and the second signal. Fire detection condition to is changed based on the identification result by the identification means and the increase rate by the increase rate detection means. do .

Advantages of the Invention

[0021] (Effect of the fire detection device) According to the fire detection device of the present invention, by changing the fire detection condition according to the type of detection target such as white smoke, black smoke, steam, etc. or the type of generation factor of these detection targets, a fire caused by smoke with a high risk of large-scale rapid smoke diffusion is detected more quickly, while for steam generated by non-fire factors, false non-fire alarms can be reliably prevented.

[0022] (Effect of optical settings) Furthermore, by irradiating the detection object in the monitoring area with light of a first wavelength and detecting the received light signal of the scattered light obtained at a first scattering angle as a first signal, and then irradiating with light of a second wavelength different from the first wavelength and detecting the received light signal of the scattered light obtained at a second scattering angle different from the first scattering angle as a second signal, the synergistic effect of the differences in the scattering characteristics of light of different wavelengths and different scattering angles makes it possible to reliably identify the type of detection object, such as white smoke, black smoke, or steam.

[0023] (Effect of identifying the detection target) Furthermore, when a fire detection target such as white smoke or black smoke is identified, the fire detection conditions are changed to make it easier to detect a fire, enabling prompt fire detection and response. Furthermore, when a non-fire detection target such as steam or dust is identified, the fire detection conditions are changed to make it harder to detect a fire, ensuring the prevention of false fire alarms.

[0024] (Effect of distinguishing between white and black smoke) Furthermore, when white smoke is identified, the fire detection conditions are changed to make it easier to detect a fire than before the change, enabling prompt fire detection and response.On the other hand, when black smoke is identified, the fire detection conditions are changed to make it easier to detect a fire than the changed fire detection conditions associated with white smoke, enabling more rapid detection and response of highly dangerous black smoke fires than white smoke fires.

[0025] (Detection of the increase rate and the effect of changing the fire detection conditions according to the increase rate) In addition, by changing the fire detection conditions so that a fire is more likely to be detected than before the change, depending on the rate of increase in the signal (at least one of the first signal and the second signal) from the fire detection target in the monitored area due to the action of light, the fire can be detected more quickly, especially for fires that are more likely to become large in scale and in which smoke spreads (rises) quickly.

[0026] (Effect of changes to fire detection conditions) Furthermore, if the fire detection conditions are changed so that fires are more easily detected than before, the specified threshold conditions and / or accumulation conditions can be made more lenient than before, i.e., the fire detection conditions can be changed to increase detection sensitivity, thereby enabling appropriate fire detection for low-risk white smoke fires and high-risk black smoke fires.On the other hand, if the fire detection conditions are changed so that fires are more difficult to detect than before, the fire threshold conditions and / or accumulation conditions can be made stricter than before, i.e., the fire detection conditions can be changed to lower detection sensitivity, thereby reliably preventing false fire alarms caused by steam from cooking or dust from cleaning.

[0027] (Effect of the first disaster prevention equipment) The present invention is a disaster prevention facility that uses the above-mentioned fire detection device, and comprises a receiver and a detector that detects a fire and transmits a fire signal to the receiver. By providing the detector with a signal detection means, an identification means, and a fire detection means, or a signal detection means, an identification means, a fire detection means, and an increase rate detection means, the problem can be addressed by simply changing the detector. Even in the case of existing equipment, the problem can be easily addressed by removing the detector attached to the detector base and replacing it with a detector that is equipped with a signal detection means, an identification means, and a fire detection means, or a detector that is also equipped with an increase rate detection means.

[0028] (Effect of the second disaster prevention equipment) The present invention is a disaster prevention facility that uses the above-mentioned fire detection device, and comprises a receiver and a detector that detects a fire and transmits a fire signal to the receiver, and the detector is provided with a signal detection means, and the receiver is provided with an identification means and a fire detection means, or an identification means, a fire detection means and an increase rate detection means, thereby eliminating the need to modify the detector and allowing the problem to be addressed by modifying only the receiver.

[0029] (Effectiveness of fire detection methods) The present invention, as a fire detection method, can provide the same effects as the above-described fire detection device. [Brief explanation of the drawings]

[0030]

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[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fire detection device, a disaster prevention system, and a fire detection method according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0032] [Basic concept of the embodiment] Fig. 1 is an explanatory diagram showing the basic concept of an embodiment of the present invention corresponding to the first disaster prevention facility, 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 first disaster prevention facility, and a fire detection method. Note that an embodiment corresponding to the second disaster prevention facility will be described separately.

[0033] The "fire detection device" is a device that detects a fire in a monitored area, and is a concept including, for example, a smoke detector, a fire detector, a fire alarm, etc.

[0034] Here, the "monitored area" is an area to be monitored by the fire detection device, and is an outdoor or indoor space with a certain extent, and is a concept including, for example, spaces such as rooms, corridors, and stairways in a building.

[0035] The fire detection device is, as an example, the detector 12 of a disaster prevention facility composed of a receiver 10 and a detector 12, and basically includes a signal detection unit 16 that functions as a signal detection means, an identification unit 18 that functions as an identification means, and a fire detection unit 20 that functions as a fire detection means. Further, it includes an increase rate detection unit 22 that functions as an increase rate detection means.

[0036] The "signal detection unit 16" is one that detects signals associated with the light action by a detection target in the monitored area by at least a first optical setting and a second optical setting, and detects a first signal obtained by the first optical setting and a second signal obtained by the second optical setting.

[0037] Here, the "detection target in the monitored area" is a detection target that generates a signal associated with the light action, and is, for example, one that generates scattered light when irradiated with light, and is a concept including smoke caused by a fire, steam or vapor caused by cooking, etc. which are non-fire factors, dust caused by cleaning, tobacco smoke caused by smoking, etc.

[0038] The term "first optical setting" includes, for example, a method of irradiating a detection target in a monitoring area with light of a first wavelength, receiving scattered light at a first scattering angle, and detecting, as a first signal, a light-receiving signal obtained by such irradiation. The term "second optical setting" includes, for example, a method of irradiating a detection target in a monitoring area with light of a second wavelength different from the first wavelength, receiving scattered light at a second scattering angle different from the first scattering angle, and detecting, as a second signal, a light-receiving signal obtained by such irradiation. The first and second optical settings, for example, can create differences in scattered light depending on the type of smoke by differentiating the scattering angles of two light-emitting elements relative to the light-receiving elements, and at the same time, create differences in scattering characteristics due to wavelength by differentiating the wavelengths of light emitted from the two light-emitting elements, and detect first and second signals that have significant differences in the light intensity of scattered light depending on the type of smoke due to the synergistic effect of the differences in scattering angles and wavelengths.

[0039] The “identification unit 18” identifies the type of the detection target or the type of the cause of the detection target based on the first signal and the second signal detected by the signal detection unit 16.

[0040] Here, the "type of detection target" is a concept that includes white smoke and black smoke that are fire detection targets, and steam (vapor), dust, etc. that are non-fire detection targets. Also, the "type of cause of detection target" is a concept that includes, for example, white smoke fire, black smoke fire, and non-fire (such as cooking as mentioned above) that correspond to each detection target.

[0041] The "fire detection unit 20" is a unit that detects a fire when a predetermined fire detection condition is met based on at least one of the first signal and the second signal detected by the signal detection unit 16, and is a concept that includes, for example, a unit that detects a fire when at least one of the first signal and the second signal meets a predetermined threshold condition, or when at least one of the first signal and the second signal meets a predetermined accumulation condition while meeting a predetermined threshold condition.

[0042] Here, "based on at least one of the first signal and the second signal" means, for example, identifying by comparing the first signal and the second signal. More specifically, for example, it includes concepts such as identifying based on the magnitude relationship between the first signal and the second signal, and identifying based on the ratio between the first signal and the second signal, etc.

[0043] Here, the "fire detection condition" is a condition for detecting a fire based on at least one of the first signal and the second signal detected by the signal detection unit 16, and is changed according to the identification result by the identification unit 18.

[0044] Also, "changed according to the identification result by the identification unit 18" means changing the fire detection condition according to the type of the detection target obtained as the identification result or the type of the cause of occurrence of the detection target.

[0045] The change of the fire detection condition according to the identification result of the identification unit 18 is optional. As an example, the identification unit 18 identifies a fire detection target and a non-fire detection target as the types of detection targets. When a fire detection target is identified, the fire detection condition is changed so that it is easier to detect a fire than before the change. On the other hand, when a non-fire detection target is identified, the fire detection condition is changed so that it is less likely to detect a fire than before the change, etc. This includes concepts such as these.

[0046] As another example, further, when white smoke is identified by the identification unit 18, the fire detection condition is changed so that it is easier to detect a fire than before the change. Also, when black smoke is identified by the identification unit 18, the fire detection condition is changed so that it is easier to detect a fire than the fire detection condition after the change associated with the identification of white smoke. This includes concepts such as enabling quicker fire detection for a high-risk black smoke fire compared to a white smoke fire, etc.

[0047] Here, "modified so as to be more likely to detect a fire than before" means changing to conditions that relax the fire detection conditions and increase the detection sensitivity. As an example, when at least one of the first signal and the second signal has set a predetermined threshold condition and / or accumulation condition, it includes relaxing (softening the condition) the threshold condition and / or accumulation condition before modification so as to be more likely to detect a fire and increasing the detection sensitivity.

[0048] Also, "modified so as to be less likely to be detected as a fire than before" means changing to conditions that tighten the fire detection conditions and decrease the detection sensitivity. As an example, when at least one of the first signal and the second signal has set a predetermined threshold condition and / or accumulation condition, it includes making the smoke value threshold condition and / or accumulation condition before modification stricter (to a strict condition) so as to be less likely to be detected as a fire and decreasing the detection sensitivity.

[0049] The "increase rate detection unit 22" is for detecting the increase rate of at least one of the first signal and the second signal detected by the signal detection unit 16. Here, "detecting the increase rate" is a concept including detecting the amount of change in which the detection value (for example, smoke density) of at least one of the first signal and the second signal per a predetermined unit time increases.

[0050] In addition, with the provision of the increase rate detection unit 22, the fire detection conditions are changed based on the identification result by the identification unit 18 and the increase rate by the increase rate detection unit 22. Although the change of the fire detection conditions in this case is optional, as an example, when identifying a fire detection target as the type of detection target and the increase rate satisfies a predetermined increase rate threshold condition, the fire detection conditions are changed so that it becomes easier to detect a fire than before the change. Concepts include, for example, changing the initially set fire detection conditions so that it becomes easier to detect a fire according to white smoke or black smoke, which is the fire detection target, and when the predetermined increase rate threshold condition is satisfied, further changing the changed fire detection conditions so that it becomes easier to detect a fire. As a result, even for the same fire of white smoke or black smoke, the higher the increase rate of at least one of the first signal and the second signal, for example, the increase rate of the detection value (smoke density), the more rapid the fire detection becomes possible.

[0051] In the following description, the "monitoring area" is a "room in a building", the "signal detection unit 16" is a "scattered light type smoke detection unit that detects the first signal and the second signal with different wavelengths and different scattering angles", the "identification unit 18" is "one that identifies the type of detection target or the type of cause of occurrence of the detection target based on the ratio of the first detection value A1 and the second detection value A2 corresponding to the smoke density of the first signal and the second signal", the "fire detection unit 20" is "one that detects a fire when a threshold condition of a predetermined smoke density is satisfied", the "increase rate detection unit 22" is "one that detects the increase rates α1 and α2 of at least one of the first detection value A1 and the second detection value A2", and the case where the "change of the fire detection conditions" is "performed by the fire detection unit 20" will be described.

[0052] [Specific content of the embodiment] The specific content of the embodiment of the fire detection device, disaster prevention equipment, and fire detection method will be described in more detail. The content will be described separately as follows. a. P-type disaster prevention equipment a1. Receiver a2. Sensor a3. Signal detection unit a4. Light emission drive and light reception detection a5. Sensor control section a6. Fire detection section b. Identifying the type of detection target and changing the fire detection conditions b1.Identification part b2. Identifying white smoke b3. Identification of black smoke b4. Identification of non-fire detection targets c. Detection of increase rate and change of fire detection conditions c1. Increase rate detection section c2. Changing the fire detection criteria based on the rate of increase d. Sensor control operation e. Basic Concept of Other Embodiments fR-type disaster prevention equipment f1.sensor f2.Receiver f3.Transmission control f4. Control operation of R-type disaster prevention equipment g. Modifications of the present invention

[0053] [aP-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" refers to a facility in which a receiver 10 monitors fires for each signal line (each signal line) to which a detector 12 is connected.

[0054] 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 only one sensor 12 as a representative. The receiver 10 is installed in a manager's office, a disaster prevention center, or the like, and multiple sensors 12 are connected to a signal line 14 that is drawn from the receiver 10 to a monitored 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 sensors 12 to the receiver 10.

[0055] (a1. Receiver) The receiver 10 includes a receiver control unit 40, a line receiver 42, a display unit 44, an operation unit 46, an alarm unit 48, and a transfer unit 50. The line receiver 42 is provided for each signal line 14 that is divided by monitoring areas, for example, by floor of a building, receives a fire alarm signal from the sensor 12, and outputs it to the receiver control unit 40.

[0056] The receiver control unit 40 is composed of a computer circuit including a CPU, a memory, and various input / output ports. When detecting the reception of a fire alarm signal by any of the line receivers 42, it performs a fire alarm operation. The fire alarm operation of the receiver control unit 40 activates the fire representative lamp of the display unit 44 and the area display lamp indicating the fire occurrence area, and also outputs a main acoustic alarm including an alarm voice message by the alarm unit 48 and performs an area acoustic alarm by activating the area acoustic device installed in the monitoring area where the fire has occurred. In addition, it gives an instruction to the transfer unit 50 to perform interlocking control of smoke exhaust and fire prevention equipment, etc.

[0057] (a2. Sensor) The configuration of the sensor 12 that functions as a fire detection device will be described in more detail. The sensor 12 includes a signal detection unit 16, a sensor control unit 24, a reporting circuit unit 26, a power supply unit 28, a light emission drive unit 36, and a light reception amplification unit 38.

[0058] (a3. Signal detection unit) The signal detection unit 16, according to a first optical setting, irradiates light with a first wavelength λ1 onto smoke, steam, dust, etc. that are detection targets in the monitoring area, and receives scattered light obtained by a first scattering angle θ1 to detect a first detection value A1 based on a first signal. According to a second optical setting, it irradiates light with a second wavelength λ2 different from the first wavelength λ1, and receives scattered light obtained by a second scattering angle θ2 different from the first scattering angle θ1 to detect a second detection value A2 based on a second signal. Its configuration and structure are arbitrary, but in a smoke detection section which is a space inside the sensor where outside air flows in but external light is blocked, for example, a first light emitting element 30, a second light emitting element 32, and a light receiving element 34 are arranged.

[0059] Figure 3 is an explanatory diagram showing the smoke detection section of the signal detection unit 16. Figure 3(A) shows the first embodiment, and Figure 3(B) shows the second embodiment.

[0060] As shown in FIG. 3(A), in this embodiment, a first light-emitting element 30, a second light-emitting element 32, and a light-receiving element 34 are arranged in a smoke detection unit 31 into which smoke from the outside flows and light from the outside is blocked, and in this embodiment, the optical axes 30a, 32a, and 34a are arranged in the same plane, having a planar arrangement structure.

[0061] The first light-emitting element 30 uses a near-infrared LED and emits light having a central wavelength of 600 nm or more, for example, light with λ1 = 900 nm, as light of the first wavelength λ1. Further, the first light-emitting element 30 is set such that the first scattering angle θ1 with respect to the intersection point P of its optical axis 30a and the optical axis 34a of the light-receiving element 34 is a predetermined angle in the range of 20° to 70°, for example, θ1 = 30°.

[0062] The second light-emitting element 32 uses a visible light LED and emits light having a central wavelength of 500 nm or less, for example, light with λ2 = 500 nm, as light of the second wavelength λ2. Further, the second light-emitting element 32 is set such that the second scattering angle θ2 with respect to the intersection point P of its optical axis 32a and the optical axis 34a of the light-receiving element 34 is a predetermined angle in the range of 110° to 150°, which is larger than the first scattering angle θ1 between the first light-emitting element 30 and the light-receiving element 34, for example, θ2 = 120°.

[0063] The light-receiving element 34 uses a photodiode having sensitivity from the infrared region to the visible light region. The first light-emitting element 30 and the second light-emitting element 32 are alternately driven to emit light. When the first light-emitting element 30 emits light, the light of the first wavelength λ1 irradiates the smoke flowing into point P, and the scattered light (forward scattered light) of the smoke corresponding to the first scattering angle θ1 is incident on and received by the light-receiving element 34, and a first signal is output as a received signal, and a first detection value A1 corresponding to the smoke concentration is detected.

[0064] Further, when the second light-emitting element 32 emits light, the light of the second wavelength λ2 irradiates the smoke flowing into point P, and the scattered light (backward scattered light) of the smoke corresponding to the second scattering angle θ2 is incident on and received by the light-receiving element 34, and a second signal is output as a received signal, and a second detection value A2 corresponding to the smoke concentration is detected.

[0065] Here, between the first detection value A1 of the scattered light received at the first scattering angle θ1 = 30° by irradiating the same smoke with light of the first wavelength λ1 = 900 nm and the first detection value A2 of the scattered light received at the second scattering angle θ2 = 120° by irradiating with light of the second wavelength λ2 = 500 nm, based on the difference in scattering efficiency, A1 > A2 is known to have the following relationship.

[0066] Also, the first detection value A1 and the second detection value A2 will be different values depending on the type of smoke that has flowed into the smoke detection unit 31, such as white smoke, black smoke, steam, etc. By comparing the two, the type of smoke can be identified. Although the identification of the type of smoke by comparing the first detection value A1 and the second detection value A2 is optional, for example, as the ratio R of the two, R = A1 / A2 can be obtained to enable identification.

[0067] For example, for white smoke (smoldering smoke) that appears white when a cotton wick is burned, the ratio R of the first detection value A1 and the second detection value A2 is, for example, R = 8.0. On the other hand, for black smoke (combustion smoke) that appears black when kerosene is burned, the ratio R of the first detection value A1 and the second detection value A2 is, for example, R = 2.3.

[0068] Therefore, there is a sufficient difference between the ratios R of the first detection value A1 and the second detection value A2 for white smoke (smoldering smoke) and black smoke (combustion smoke). For example, by setting a value in the range of 5 to 6 as the first discrimination threshold Rth1 for discriminating the type of smoke with respect to the ratio R, for example, Rth1 = 5, if the ratio R is greater than or equal to Rth1, it can be discriminated as white smoke, and if it is less than Rth1, it can be discriminated as black smoke.

[0069] On the one hand, in the case of steam or vapor, since the particle size is sufficiently larger than that of smoke particles, the scattering efficiency at a small scattering angle is sufficiently higher than that of smoke during a fire. The first detection value A1 of the scattered light at the first scattering angle θ1 = 30° by irradiating light of the first wavelength λ1 is sufficiently large, and the ratio R with the second detection value A2 of the scattered light at the second scattering angle θ2 = 120° by irradiating light of the second wavelength λ2 will have a large value of 10 or more.

[0070] Therefore, as the second discrimination threshold value Rth2 for discriminating steam or vapor, a value in the range of 10 to 12, for example, Rth2 = 12 is set. In the case of this or more, it can be discriminated as a non-fire detection target such as steam or vapor.

[0071] This is the same for cigarette smoke and dust. Since a large value of the ratio R of 10 or more can be obtained, when the second discrimination threshold value Rth2 is 12 or more, it can be discriminated as a non-fire detection target.

[0072] Next, a second embodiment of the smoke detection unit shown in Fig. 3(B) will be described. As shown in Fig. 3(B), in this embodiment, a light emitting element 35, a first light receiving element 34(34 - 1) and a second light receiving element 34(34 - 2) are arranged in the smoke detection unit 31, and in this embodiment, the respective optical axes 35a, 34 - 1a, 34 - 2a are arranged in the same plane in a planar arrangement structure.

[0073] The light emitting element 35 emits light including the first wavelength λ1 and the second wavelength λ2 simultaneously. The light of the first wavelength λ1 emitted from the light emitting element 35 has a center wavelength determined to be 600 nm or more, and the light of the second wavelength λ2 has a center wavelength determined to be 500 nm or less. In this embodiment, the first wavelength λ1 is determined to be, for example, 700 nm, and the second wavelength λ2 is determined to be, for example, 450 nm.

[0074] The light-emitting element 35 irradiates light from the infrared region to the visible light region, and its structure and type are arbitrary. For example, a white LED (white light-emitting diode) is used. The white LED combines, for example, a blue LED and a phosphor, and passes the light of the blue LED through the phosphor to emit white light. This emission color includes light with a first wavelength λ1 = 700 nm and light with a second wavelength λ2 = 450 nm, and the inspection smoke section 31 can be irradiated with the light of the first wavelength λ1 and the second wavelength λ2 simultaneously.

[0075] Also, as the light-emitting element 35 of this embodiment, a two-color LED (two-color light-emitting diode) can also be used. The two-color LED includes a first light-emitting chip that emits light with a first wavelength λ1 = 700 nm and a second light-emitting chip that emits light with a second wavelength λ2 = 450 nm. By driving both simultaneously, the light of the first wavelength λ1 and the second wavelength λ2 can be irradiated into the inspection smoke section 31 simultaneously.

[0076] A photodiode (PD) having sensitivity to the first wavelength λ1 is used for the first light-receiving element 34 (34-1), and a photodiode (PD) having sensitivity to the second wavelength λ2 is used for the second light-receiving element 34 (34-2).

[0077] Also, as the first light-receiving element 34 (34-1) and the second light-receiving element 34 (34-2), a filter layer that receives only the respective wavelength bands of the first wavelength λ1 and the second wavelength λ2 may be provided on a broadband photodiode having sensitivity in the visible light wavelength band in the PD molding (transparent cover member), or a filter that transmits the respective wavelength bands of the first wavelength λ1 and the second wavelength λ2 may be arranged in front of the broadband photodiode.

[0078] The first light-receiving element 34(34-1) sets the first scattering angle θ1 with respect to the intersection point P of its optical axis 34-1a and the optical axis 35a of the light-emitting element 35 to a predetermined angle in the range of 20° to 70°, for example, θ1 = 30°. When the light including the first wavelength λ1 from the light-emitting element 35 irradiates the smoke flowing into point P, the scattered light (forward scattered light) of the smoke corresponding to the first scattering angle θ1 enters and is received by the first light-receiving element 34(34-1), a first signal is output as a received signal, and a first detection value A1 corresponding to the smoke concentration is detected.

[0079] Also, the second light-receiving element 34(34-2) sets the second scattering angle θ2 with respect to the intersection point P of its optical axis 34-2a and the optical axis 35a of the light-emitting element 35 to a predetermined angle in the range of 110° to 160°, which is larger than the first scattering angle θ1 between the first light-receiving element 34(34-1) and the light-emitting element 35, for example, θ2 = 120°. When the light including the second wavelength λ2 from the light-emitting element 35 irradiates the smoke flowing into point P, the scattered light (backward scattered light) of the smoke corresponding to the second scattering angle θ2 enters and is received by the second light-receiving element 34(34-2), a second signal is output as a received signal, and a second detection value A2 corresponding to the smoke concentration is detected.

[0080] Also in this embodiment, the first detection value A1 of the scattered light obtained by irradiating the same smoke with light of the first wavelength λ1 = 700 nm and receiving it at the first scattering angle θ1 = 30° and the first detection value A2 of the scattered light obtained by irradiating the same smoke with light of the second wavelength λ2 = 450 nm and receiving it at the second scattering angle θ2 = 120° are based on the difference in scattering efficiency, A1 > A2 resulting in a relationship such that, for example, a first discrimination threshold Rth1 is set to Rth1 = 5. If it is equal to or greater than Rth1, it can be discriminated as white smoke, and if it is less than Rth1, it can be discriminated as black smoke.

[0081] Also, for steam, vapor, dust, tobacco smoke, etc., a second discrimination threshold Rth2 is set to, for example, Rth2 = 12. In cases where it is equal to or greater than this value, it can be discriminated as a non-fire detection target such as steam, vapor, dust, tobacco smoke, etc.

[0082] (a4. Light-emitting drive and light-receiving detection) 2 is provided with the first embodiment of the smoke detector shown in Fig. 3(A), and is therefore provided with a first light-emitting element 30, a second light-emitting element 32, and a light-receiving element 34. The first light-emitting element 30 and the second light-emitting element 32 are driven to emit light alternately at predetermined intervals by a light-emitting drive unit 36, and the first and second signals output sequentially from the first light-emitting element 30 and the second light-emitting element 32 as received light signals are amplified by a received light amplifier unit 38 and read into the sensor control unit 24, where a first detection value A1 and a second detection value A2 corresponding to the smoke density are detected.

[0083] (a5. Sensor control section) The detector control unit 24 is composed of a computer circuit equipped with a CPU, memory, and various input / output ports, and has the functions of an identification unit 18, a fire detection unit 20, and an increase rate detection unit 22, which are components of the fire detection device of this embodiment, as functions realized by executing a program.

[0084] The sensor control unit 24 acquires a first detection value A1 and a second detection value A2 corresponding to the smoke concentration by reading the signal from the light receiving amplifier unit 38 through A / D conversion synchronized with the timing of the light emission drive of the first light emitting element 30 and the second light emitting element 32, and when the fire detection unit 20 detects a fire based on the acquired first detection value A1 and second detection value A2, it activates the alarm circuit unit 26, short-circuits the positive signal line 14a and the negative signal line 14b to a low impedance, passes a fire alarm current, and transmits a fire alarm signal to the receiver 10.

[0085] (a6. Fire detection section) The fire detection unit 20 provided as fire detection means in the sensor control unit 24 detects a fire when at least one of the acquired first detection value A1 and second detection value A2 satisfies a predetermined fire detection condition. Here, fire detection based on the first detection value A1 will be described as an example, but the same applies to the case where fire detection is based on both the first detection value A1 and the second detection value A2.

[0086] The fire detection conditions of the fire detection unit 20 are arbitrary, but as an example, a fire is detected when the first detection value A1 satisfies a predetermined smoke density threshold condition. Here, the smoke density threshold condition is a condition under which a fire is detected when the first detection value A1 is equal to or greater than a predetermined smoke density threshold Dth0. For example, if the detector 12 is a type 2 sensitivity detector, a fire is detected when the first detection value A1 is equal to or greater than the smoke density threshold Dth0=10 (% / m) corresponding to the type 2 sensitivity.

[0087] A "Class 2 sensitivity detector" refers to a detector with a legally mandated nominal activation concentration K of 10% / m. When tested for activation, the detector activates within 30 seconds when placed in an airflow of 20-40 cm / sec containing smoke at a concentration of (nominal activation concentration K) x 1.5 = 10% / m x 1.5 = 15% / m. Furthermore, when tested for deactivation, the detector fails to activate within 5 minutes when placed in an airflow of 20-40 cm / sec containing smoke at a concentration of (nominal activation concentration K) x 0.5 = 10% / m x 0.5 = 5% / m, for example, in the case of a non-accumulation detector. In addition to such Class 2 sensitivity detectors with K = 10% / m, "Class 1 sensitivity detectors" with a nominal activation concentration K = 5% / m or "Class 3 sensitivity detectors" with a nominal activation sensitivity K = 15% / m are also acceptable.

[0088] Alternatively, as another fire detection condition, a fire may be detected when a predetermined smoke density threshold condition is met and a predetermined accumulation condition is met. For example, if detector 12 is a type 2 sensitivity detector, a fire is detected when the first detection value A1 is equal to or greater than the smoke density threshold Dth0=10 (% / m) corresponding to type 2 sensitivity for a predetermined accumulation time T0, for example, T0=20 seconds or more.

[0089] Such fire detection conditions, for example, the smoke density threshold Dth0 and the accumulation time T0, are initially set, and in this embodiment, the initially set fire detection conditions, for example, the smoke density threshold Dth0 and the accumulation time T0, are characterized in that they are changed based on the type of smoke being detected.

[0090] [b. Identification of the Type of Detection Target and Change of Fire Detection Conditions] (b1. Identification Unit) The identification unit 18 provided in the sensor control unit 24 as an identification means identifies the type of the detection target or the type of the cause of occurrence of the detection target based on the first detection value A1 and the second detection value A2 acquired from the signal detection unit 16. Accordingly, the fire detection unit 20 changes the fire detection conditions based on the identification result of the identification unit 18.

[0091] Fig. 4 shows an example of the identification of the detection target and the change of the fire detection conditions according to the identification result, and also shows the increase rate of the detection value and the change of the fire detection conditions.

[0092] As shown in Fig. 4, the types of detection targets identified by the identification unit 18 are roughly classified into, for example, fire detection targets and non-fire detection targets. The types of fire detection targets include white smoke and black smoke. The types of causes of white smoke generation include white smoke fire, smoldering fire, combustion of cotton wicks used in fire tests, etc. The causes of black smoke include black smoke fire, combustion fire, combustion of kerosene used in fire tests, etc.

[0093] (b2. Identification of White Smoke) When the ratio R = A1 / A2 of the first detection value A1 and the second detection value A2 obtained from the signal detection unit 16 by the identification unit 18 is, for example, not less than the first identification threshold value Rth1 = 5 and less than the second identification threshold value Rth2 = 12 (Rth1 ≤ R < Rth2), it is identified as white smoke. When white smoke is identified by the identification unit 18, the fire detection unit 20 changes the initially set fire detection conditions so that fire can be detected more easily than before the change. Note that the identification unit 18 may identify the types such as white smoke fire and smoldering fire that are the causes of white smoke generation.

[0094] The initially set fire detection conditions are, for example, a smoke concentration threshold Dth0 = 10 (% / m) corresponding to a two-sensitivity detector and an accumulation time T0 = 20 (seconds). When white smoke is discriminated, the initially set threshold Dth0 = 10 (% / m) is changed to a first threshold Dth1 = 7.5 (% / m) that is more likely to be detected as a fire than before the change, and the initially set accumulation time T0 = 20 (seconds) is changed to a first accumulation time T1 = 15 (seconds) that is more likely to be detected as a fire than before the change.

[0095] Therefore, when white smoke is identified, a fire is detected when at least one of the first detection value A1 and the second detection value A2 obtained from the signal detection unit 16 reaches the changed, for example, first threshold Dth1 = 7.5 (% / m), and a fire can be detected earlier compared to the threshold Dth0 = 10 (% / m) before the change.

[0096] (b3. Identification of black smoke) The identification unit 18 identifies black smoke when the ratio R = A1 / A2 of the first detection value A1 and the second detection value A2 obtained from the signal detection unit 16 is less than, for example, the first identification threshold Rth1 = 5 (R < 5). Note that the identification unit 18 may also identify the types of black smoke fires or combustion fires that are the causes of black smoke generation.

[0097] When the fire detection unit 20 identifies black smoke by the identification unit 18, it changes the initially set threshold Dth0 = 10 (% / m) and accumulation time T0 = 20 (seconds) to fire detection conditions that are more likely to detect a fire than the changed fire detection conditions associated with the identification of white smoke, for example, the first threshold Dth1 = 7.5 (% / m) and the first accumulation time T1 = 15 (seconds), for example, the second threshold Dth2 = 5.0 (% / m) and the second accumulation time T2 = 10 (seconds).

[0098] Therefore, when black smoke is identified, a fire is detected when at least one of the first detection value A1 and the second detection value A2 obtained from the signal detection unit 16 reaches the changed second threshold value Dth2=5.0 (% / m), for example, and a fire can be detected earlier than the threshold value before the change Dth0=10 (% / m), and furthermore, a fire can be detected earlier than the first threshold value Dth1=7.5 (% / m), which is changed when white smoke is identified.

[0099] (b4. Identification of non-fire detection targets) When the ratio R=A1 / A2 of the first detection value A1 to the second detection value A2 acquired from the signal detection unit 16 is equal to or greater than, for example, a second discrimination threshold Rth2=12 (R≧12), the discrimination unit 18 discriminates the object as a non-fire detection target, including steam (vapor), dust, cigarette smoke, etc. When the discrimination unit 18 discriminates a non-fire detection target such as steam, the fire detection unit 20 changes the initially set threshold Dth0=10 (% / m) and accumulation time T0=20 (seconds) to a third threshold Dth3=15 (% / m) and a third accumulation time T3=30 (seconds), which make it less likely to be detected as a fire.

[0100] Therefore, when a non-fire detection target such as steam is identified, the first detection value A1 and second detection value A2 of the non-fire detection target such as steam obtained from the signal detection unit 16 cannot reach the changed third threshold Dth3 = 15 (% / m), making it possible to reliably prevent non-fire alarms.

[0101] The values of the threshold values Dth1 to Dth3 and the accumulation times T1 to T3 shown in FIG. 4 are examples. Dth3>Dth0>Dth1>Dth2 T3>T0>T1>T2 can be any value that satisfies the following relationship:

[0102] [c. Detection of Increase Rate and Change of Fire Detection Conditions] Next, the detection of the increase rate based on at least one of the first detection value A1 and the second detection value A2 acquired from the signal detection unit 16 and the change of the fire detection condition based on the increase rate will be described in detail.

[0103] (c1. Increase rate detection unit) The increase rate detection unit 22 provided as the increase rate detection means in the detector control unit 24 of the detector 12 shown in FIG. 2 detects at least one of the increasing change amounts ΔD1 and ΔD2 of the first detection value A1 and the second detection value A2 obtained from the signal detection unit 16 per a predetermined unit time, for example, per minute, as the first increase rate α1 [(% / m) / second] and the second increase rate α2 [(% / m) / second].

[0104] The first increase rate α1 of the first detection value A1 corresponding to the smoke density associated with a fire and the second increase rate α2 of the second detection value A2 depend on the diffusion speed (rising speed) of the smoke according to the scale of the fire that has occurred. For example, in a fire of polyurethane or the like accompanied by black smoke, a large amount of smoke is generated due to the high combustion speed, and the first increase rate α1 of the first detection value A1 detected by the signal detection unit 16 and the second increase rate α2 of the second detection value A2 become large.

[0105] On the other hand, in a smoldering fire accompanied by white smoke or the like, the amount of smoke generated is small due to the slow combustion speed, and the first increase rate α1 of the first detection value A1 obtained from the signal detection unit 16 and the second increase rate α2 of the second detection value A2 become small. Further, when non-fire detection targets such as smoke and steam associated with cooking or tobacco smoke occur, the first increase rate α1 of the first detection value A1 and the second increase rate α2 of the second detection value A2 obtained from the signal detection unit 16 show an increase rate lower than that of a smoldering fire or the like.

[0106] FIG. 5 is a time chart showing the characteristics of the time change of smoke densities with different increase rates that increase linearly with the passage of time, taking the smoke density corresponding to the first detection value A1 as an example. As shown in FIG. 5, the increase rate of characteristic a is the highest, for example, an oil fire that burns explosively. On the other hand, characteristic e is, for example, a smoldering fire in which a futon or the like smolders, and characteristics b to d indicate fires of scales in between. Further, characteristic f is the case where non-fire detection targets such as smoke and steam associated with cooking or tobacco smoke occur. It should be noted that the increase rate of the smoke density in an actual fire does not become a straight line (constant increase rate), and as is well known, the increase rate changes randomly with the passage of time.

[0107] (c2. Modification of Fire Detection Conditions Based on Increase Rate) When at least one of the first increase rate α1 of the first detection value A1 and the second increase rate α2 of the second detection value A2 satisfies a predetermined increase rate threshold condition in the increase rate detection unit 22, for example, when it is equal to or higher than a predetermined increase rate threshold αth, the fire detection unit 20 changes the fire detection conditions so as to make it easier to detect a fire than before and detects the fire.

[0108] Here, the increase rate threshold αth of the increase rate α of the smoke density for changing the fire detection conditions is arbitrary. For example, in FIG. 5, the increase rate of the characteristic g, which is approximately in the middle between the characteristic e of the smoldering fire with the lowest increase rate among the fire detection targets and the characteristic f of the smoldering fire, is set as the increase rate threshold αth.

[0109] The fire detection unit 20 changes the fire detection conditions based on the discrimination result of white smoke and black smoke discriminated by the discrimination unit 18 and the increase rate detected by the increase rate detection unit 22. The degree of change in the fire detection conditions based on the increase rate is different when white smoke is discriminated and when black smoke is discriminated.

[0110] When the fire detection unit 20 discriminates white smoke by the discrimination unit 18, the fire detection conditions are changed based on the detection of the increase rate so as to be more likely to detect a fire than the fire detection conditions changed by the discrimination of white smoke. For example, as shown in FIG. 4, when white smoke is discriminated and the increase rate (at least one of α1 and α2) is equal to or higher than a predetermined increase rate threshold αth, the initially set threshold Dth0 = 10 (% / m) and the accumulation time T0 = 20 (seconds), which are the fire detection conditions before the change, are changed to the fourth threshold Dth4 = 5.0 (% / m) and the fourth accumulation time T4 = 10 (seconds), which are the fire detection conditions that are more likely to detect a fire.

[0111] The fire detection conditions changed based on this increase rate are conditions that are more likely to detect a fire than the first threshold Dth1 = 7.5 (% / m) and the first accumulation time T1 = 15 (seconds) of the fire detection conditions changed by the discrimination of white smoke.

[0112] Further, when the fire detection unit 20 identifies black smoke in the identification unit 18, the fire detection conditions are changed based on the detection of the increase rate so that it is easier to detect a fire than the fire detection conditions changed by the identification of black smoke. For example, as shown in FIG. 4, when black smoke is identified and the increase rate (at least one of α1 and α2) is equal to or higher than a predetermined increase rate threshold αth, the initially set threshold value Dth0 = 10 (% / m) and the initial accumulation time T0 = 20 (seconds), which are the fire detection conditions before the change, are changed to the fifth threshold value Dth5 = 2.5 (% / m) and the fifth accumulation time T5 = 5 (seconds), which are the fire detection conditions, so that it is easier to detect a fire.

[0113] The fire detection conditions changed based on this increase rate are conditions that make it easier to detect a fire than the second threshold value Dth2 = 5.0 (% / m) and the second accumulation time T2 = 10 (seconds) of the fire detection conditions changed by the identification of black smoke.

[0114] Note that the values of the threshold values Dth1 to Dth5 and the accumulation times T1 to T5 shown in FIG. 4 are examples, Dth3 > Dth0 > Dth1 > Dth2 Dth1 > Dth4 Dth2 > Dth5 T3 > T0 > T1 > T25 T1 > T4 T2 > T5 and can be any values having the relationship of.

[0115] [d. Control operation of the sensor] FIG. 6 is a flowchart showing the control operation according to the embodiment of the sensor in FIG. 2, and is the control operation of the sensor control unit 24.

[0116] As shown in FIG. 6, the sensor control unit 24 obtains a first detection value A1 and a second detection value A2 corresponding to the smoke density from the first signal and the second signal detected by the signal detection unit 16 in step S1. For example, taking the smoke detection unit 31 in FIG. 3(A) as an example, the light emitting drive unit 36 sequentially drives the first light emitting element 30 and the second light emitting element 32 to emit light at a predetermined cycle, and the light receiving element 34 receives the scattered light with different wavelengths and scattering angles such as smoke or steam. The first signal and the second signal amplified by the light receiving amplification unit 38 are read by A / D conversion in synchronization with each light emission to obtain a first detection value A1 and a second detection value A2 corresponding to the smoke density.

[0117] Subsequently, the ratio R = A1 / A2 of the first detection value A1 and the second detection value A2 obtained in step S2 is calculated, and at least one of the first increase rate α1 of the first detection value A1 and the second increase rate α2 of the second detection value A2 is detected in step S3. Subsequently, in step S4, if the ratio R is greater than or equal to the first discrimination threshold Rth1 = 5 and less than the second discrimination threshold Rth2 = 12, it is discriminated as white smoke, and the process proceeds to step S5. If the increase rate detected in step S3 in step S5 is smaller than the increase rate threshold αth, the process proceeds to step S6, and the initially set fire detection condition thresholds Dth0 = 10 (% / m) and accumulation time T0 = 20 (seconds) are changed to the first threshold Dth1 = 7.5 (% / m) and the first accumulation time T1 = 15 (seconds) which are the fire detection conditions based on the white smoke discriminated in step S4, so that it becomes easier to detect a fire, and the process proceeds to step S14.

[0118] In step S14, when at least one of the first detection value A1 and the second detection value A2 obtained in step S1 satisfies the changed fire detection conditions, a fire is detected and the process proceeds to step S15, and the alarm circuit unit 26 is instructed to transmit a fire alarm signal, and the alarm circuit unit 26 is activated to transmit a fire alarm signal to the receiver 10. Subsequently, in step S16, it is determined whether to recover from the interruption of the power supply to the signal line 14 due to the recovery operation at the receiver 10, and the process returns to the first sensor control in step S1.

[0119] On the other hand, in step S5, if the increase rate detected in step S3 is equal to or higher than a predetermined increase rate threshold αth, the process proceeds to step S7, where the initially set threshold Dth0 = 10 (% / m) and accumulation time T0 = 20 (seconds), which are the fire detection conditions before the change, are changed to the fourth threshold Dth4 = 5.0 (% / m) and the fourth accumulation time T4 = 10 (seconds) so as to facilitate fire detection, and then the process proceeds to step S14 to perform the process of detecting a fire.

[0120] Also, if white smoke is not identified in step S4, the process proceeds to step S8. If the ratio R is smaller than the first discrimination threshold Rth1 = 5, black smoke is discriminated and the process proceeds to step S9. In step S9, if the increase rate detected in step S3 is smaller than the increase rate threshold αth, the process proceeds to step S10, where the initially set threshold Dth0 = 10 (% / m) and accumulation time T0 = 20 (seconds), which are the fire detection conditions before the change, are changed to the second threshold Dth2 = 5.0 (% / m) and the second accumulation time T2 = 10 (seconds), which are the fire detection conditions based on the black smoke discriminated in step S8, so as to facilitate fire detection, and then the process proceeds to step S14 to perform the process of detecting a fire.

[0121] On the other hand, in step S9, if the increase rate detected in step S3 is equal to or higher than a predetermined increase rate threshold αth, the process proceeds to step S11, where the initially set threshold Dth0 = 10 (% / m) and accumulation time T0 = 20 (seconds), which are the fire detection conditions before the change, are changed to the fifth threshold Dth5 = 2.5 (% / m) and the fifth accumulation time T5 = 5 (seconds) so as to facilitate fire detection, and then the process proceeds to step S14 to perform the process of detecting a fire.

[0122] Also, if black smoke is not discriminated in step S8, the process proceeds to step S12. If the ratio R is equal to or higher than the second discrimination threshold Rth2 = 12, it is discriminated as a non-fire detection target such as steam, and the process proceeds to step S13, where the initially set threshold Dth0 = 10 (% / m) and accumulation time T0 = 20 (seconds), which are the fire detection conditions before the change, are changed to the third threshold Dth3 = 15 (% / m) and the third accumulation time T3 = 30 (seconds) so as to make it difficult to detect a fire, and then the process proceeds to step S14 to perform the process of detecting a fire.

[0123] Furthermore, when non-fire detection targets such as steam are not identified in step S12, the process proceeds to step S14 while maintaining the initially set fire detection conditions, i.e., the threshold value Dth0 = 10 (% / m) and the accumulation time T0 = 20 (seconds), to perform the process of detecting a fire.

[0124] [e. Other basic concepts of the embodiment] FIG. 7 is an explanatory diagram showing other basic concepts of the embodiment corresponding to the second disaster prevention facility. In a fire notification facility as an example of the second disaster prevention facility including a receiver 10 and a sensor 12, a signal detection unit 16 that functions as a signal detection means of a fire detection device is provided in the sensor 12, and an identification unit 18 that functions as an identification means of the fire detection device and a fire detection unit 20 that functions as a fire detection means are provided in the receiver 10. Furthermore, an increase rate detection unit 22 that functions as an increase rate detection means is provided in the receiver 10.

[0125] The signal detection unit 16 provided in the sensor 12, the identification unit 18, the fire detection unit 20, and the increase rate detection unit 22 provided in the receiver 10 are basically the same as the signal detection unit 16, the identification unit 18, the fire detection unit 20, and the increase rate detection unit 22 provided in the sensor of FIG. 1. The first detection value A1 and the second detection value A2 obtained from the first signal and the second signal detected by the signal detection unit 16 of the sensor 12 are transmitted to the receiver 10 through the transmission line 114. On the receiver 10 side, the type of the detection target is identified, a fire is detected when the fire detection conditions are satisfied, the fire detection conditions are changed based on the identification result of the detection target, and the fire detection conditions are changed based on the increase rate.

[0126] Next, the specific content of the embodiment corresponding to FIG. 7 will be described in more detail.

[0127] [f. R-type disaster prevention facility] FIG. 8 is an explanatory diagram of an R-type (Record-type) disaster prevention facility showing the specific content of the embodiment corresponding to FIG. 7. Here, the "R-type disaster prevention facility" is a facility that monitors a fire for each sensor (in sensor units) by performing transmission between the receiver 10 and the sensor 12.

[0128] As shown in FIG. 8, the R-type disaster prevention equipment of the present embodiment includes a receiver 10 and sensors 12, and a plurality of sensors 12 are 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 and transmits and receives signals between the receiver 10 and the sensors 12 by a predetermined transmission method. Note that a dedicated power supply line may be provided.

[0129] (f1. Sensor) Similar to the embodiment of FIG. 2, the sensor 12 includes, for example, a signal detection unit 16 having a smoke detection structure shown in FIG. 3(A), a sensor control unit 24, a power supply unit 28, a light emission drive unit 36, and a light reception amplification unit 38. However, it is different in that a transmission unit 60 is provided because signals are transmitted and received between the sensor 12 and the receiver 10 by a predetermined transmission method. Further, the sensor control unit 24 is not provided with the functions of the identification unit 18, the fire detection unit 20, and the increase rate detection unit 22, which are components of the fire detection device of the present invention shown in FIG. 2. These functions are provided on the receiver 10 side.

[0130] (f2. Receiver) Similar to the embodiment of FIG. 2, the receiver 10 includes a receiver control unit 40, a display unit 44, an operation unit 46, an alarm unit 48, and a transfer unit 50. However, it is different in that a transmission unit 62 is provided because signals are transmitted and received between the receiver 10 and the sensors 12 by a predetermined transmission method. Further, the receiver control unit 40 is different in that the functions of the identification unit 18, the fire detection unit 20, and the increase rate detection unit 22, which are components of the fire detection device of the present invention, are provided as functions realized by program execution. The identification unit 18, the fire detection unit 20, and the increase rate detection unit 22 provided in the receiver 10 are basically the same as those provided in the sensor 12 in the embodiment of FIG. 2.

[0131] (f3. Transmission control) In the R-type disaster prevention equipment, a unique address is set for the sensor 12, and the receiver 10 transmits a batch A / D conversion command signal at a predetermined cycle, for example, a 1-minute cycle. All the sensors 12 that have received the batch A / D conversion command signal perform A / D conversion and hold (store) the first detection value A1 and the second detection value A2 corresponding to the first signal and the second signal obtained by receiving scattered light at different wavelengths and different scattering angles by the signal detection unit 16. Subsequently, the receiver 10 performs polling by transmitting a call signal that sequentially designates the sensor addresses to cause each sensor 12 to return a response signal including the first detection value A1 and the second detection value A2.

[0132] When the first detection value A1 or the second detection value A2 corresponding to the smoke concentration of the sensor 12 reaches a predetermined fire omen level (preliminary fire detection level), for example, 1 (% / m), it is detected as a fire omen, and a fire interrupt signal is transmitted to the receiver 10.

[0133] The receiver 10 that has received the fire interrupt signal from the sensor 12 transmits a group search command signal designating the group address, performs a group search to identify the group address to which the sensor 12 that has responded to the fire interrupt signal belongs, and subsequently transmits a within-group search command signal that sequentially designates the sensor addresses within the searched group address, and identifies the address of the sensor 12 that has responded to the fire interrupt signal, that is, the address of the sensor 12 detected as a fire omen.

[0134] Subsequently, the receiver 10 transmits an A / D conversion command signal and a call signal designating the address of the sensor 12 detected as a fire omen at a predetermined cycle shorter than normal, intensively acquires the first detection value A1 and the second detection value A2 from the sensor 12 detected as a fire omen, and performs control to detect a fire by the discrimination unit 18, the fire detection unit 20, and the increase rate detection unit 22 provided in the receiver control unit 40. Note that the transmission control between the receiver 10 and the sensor 12 is an example, and any known transmission control can be applied.

[0135] (f4.Control operation of R-type disaster prevention equipment) FIG. 9 is a flowchart showing the control operation according to the embodiment of the R-type disaster prevention equipment of FIG. 8 in a time chart format.

[0136] As shown in FIG. 9, the receiver 10, as a fire monitoring transmission process in step S21, transmits a batch A / D conversion command signal at a predetermined period, for example, a 1-minute period, and then transmits a call signal specifying the sensor address, and receives a response signal from the sensor 12. On the other hand, the sensor 12, as a fire monitoring response process in step S22, receives the batch A / D conversion command signal from the receiver 10 and stores and holds the first detection value A1 and the second detection value A2 obtained at that time. When a call signal specifying its own address is subsequently received, a response signal including the first detection value A1 and the second detection value A2 is transmitted.

[0137] Subsequently, when the sensor 12 determines in step S23 that the smoke density of the acquired first detection value A1 or second detection value A2 has reached a predetermined fire omen level, for example, 1 (% / m) or more, it proceeds to step S24 and transmits a fire interrupt signal to the receiver 10 as a fire omen transmission process. The receiver 10, as a fire omen reception process in step S25, searches for and identifies the sensor address that transmitted the fire interrupt signal based on the reception of the fire interrupt signal from the sensor 12.

[0138] The receiver 10 determines in step S26 whether a fire interrupt signal has been received from the sensor 12. If no fire interrupt signal has been received, it returns to step S21. If a fire interrupt signal has been received, it proceeds to the following step S27. On the other hand, if a fire interrupt signal has been transmitted, it proceeds to step S27.

[0139] In step S27, the receiver 10 repeatedly transmits, at a short period, the batch A / D conversion command signal as the detection value A1, A2 reception process and the call signal specifying the address of the sensor 12 that transmitted the fire interrupt signal, causing the sensor 12 to perform the detection value A1, A2 transmission process in step S28, and intensively receiving the first detection value A1 and the second detection value A2 from the sensor 12 where a fire omen has been detected.

[0140] Subsequently, the receiver 10 proceeds to step S29, calculates the ratio R = A1 / A2 based on the acquired first detection value A1 and second detection value A2, and the increase rate detection unit 22 detects the increase rate of at least one of the first detection value A1 and the second detection value A2. Subsequently, in step S30, the discrimination unit 18 discriminates the type of the detection target such as white smoke, black smoke, or steam based on the ratio R, and changes the fire detection condition based on the discrimination result. This change of the fire detection condition is the same as that shown in the list of FIG. 4 as an example.

[0141] Subsequently, the receiver 10 proceeds to step S31, and changes the fire detection condition based on the detected increase rate. This change of the fire detection condition based on the increase rate is also the same as that shown in the list of FIG. 4 as an example. Subsequently, the receiver 10 proceeds to step S32. When it is determined that at least one of the first detection value A1 and the second detection value A2 satisfies the initially set fire detection condition or the changed fire detection condition, a fire is detected and the process proceeds to step S33, where fire alarm processing including sounding of a main acoustic alarm and a zone acoustic alarm, display of the fire occurrence location based on the fire and the detected sensor address, and interlocking control of smoke exhaust and supply equipment is performed.

[0142] Subsequently, when the receiver 10 determines in step S34 that recovery is due to a recovery operation accompanying extinguishment of the fire, it transmits a recovery signal to the sensor 12 in step S35 and returns to the fire monitoring transmission process of step S21. Further, when the sensor 12 determines in step S36 that the recovery signal has been received, it returns to the fire monitoring response process of step S22.

[0143] [g. Modification Example of the Present Invention] An embodiment which is a modification example of the present invention will be described in more detail.

[0144] (Fire Detection Device) The fire detection device of the above-described embodiment takes as an example the case of including a signal detection unit 16, a discrimination unit 18, a fire detection unit 20, and an amplification rate detection unit 22. However, the present invention is not limited thereto, and includes a fire detection device having a signal detection unit 16, a discrimination unit 18, and a fire detection unit 20 as a basic configuration excluding the amplification rate detection unit 22.

[0145] (fire alarm) Although 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, a residential fire alarm, for example, equipped with a means for detecting a fire from smoke density and a means for issuing an alarm about the fire, may also be configured as a fire detection device. In the case of a fire alarm, the fire alarm will be provided with the functions of a signal detection unit 16, a discrimination unit 18, a fire detection unit 20, and an increase rate detection unit 22 that constitute a fire detection device, similar to the sensor 12 of the disaster prevention equipment shown in Figures 1 and 2.

[0146] (Fire detection conditions) In the fire detection device of the above embodiment, the fire detection unit 20 changes the fire detection conditions in accordance with the identification result by the identification unit 18, but this is not limited to this, and for example, the identification unit 18 may change the fire detection conditions in accordance with the identification result, and the fire detection unit 20 may detect a fire under the changed fire detection conditions. The same applies when the fire detection conditions are changed based on the increase rate detected by the increase rate detection unit 22.

[0147] (others) Furthermore, the present invention includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the numerical values shown in the above embodiments. [Explanation of symbols]

[0148] 10: Receiver 12: Sensor 14: Signal line 16: Signal detection unit 18: Identification unit 20: Fire detection unit 22: Increase rate detection unit 24: Sensor control unit 26: Alarm circuit section 28: Power supply section 30: First light-emitting element 32: Second light-emitting element 34: Light receiving element 34(34-1): First light receiving element 34(34-2): Second light receiving element 35: Light-emitting element 36: Light emitting drive unit 38: Optical amplification unit 40: Receiver control unit 42: Line receiver 44: Display unit 46: Operation unit 48: Alarm unit 50: Transfer reporting unit 60, 62: Transmission unit 114: Transmission line

Claims

1. A signal associated with the optical action on a detection target in a monitoring area is detected by at least a first optical setting and a second optical setting, and signal detection means for detecting a first signal obtained by the first optical setting and a second signal obtained by the second optical setting; discriminating means for discriminating, based on the first signal and the second signal detected by the signal detection means, between a fire detection target and a non-fire detection target as types of the detection target, and discriminating between white smoke and black smoke as types of the fire detection target; fire detection means for detecting a fire when a predetermined fire detection condition is satisfied based on at least one of the first signal and the second signal detected by the signal detection means; comprising wherein the fire detection condition is when the white smoke is discriminated as the fire detection target by the discriminating means, it is changed so as to be more easily detected as a fire than the fire detection condition initially set by the fire detection means; when the black smoke is discriminated as the fire detection target by the discriminating means, it is changed so as to be more easily detected as a fire than the fire detection condition after the change associated with the discrimination of the white smoke by the fire detection means; when the non-fire detection target is discriminated by the discriminating means, it is changed so as to be less easily detected as a fire than the fire detection condition initially set by the fire detection means, characterized by a fire detection device.

2. The fire detection device according to claim 1, wherein the signal detection means irradiates the detection target in the monitoring area with light of a first wavelength by the first optical setting and detects a light reception signal of scattered light obtained at a first scattering angle as the first signal; irradiates the detection target in the monitoring area with light of a second wavelength different from the first wavelength by the second optical setting and detects a light reception signal of scattered light obtained at a second scattering angle different from the first scattering angle as the second signal, characterized by a fire detection device.

3. The fire detection device according to claim 1 or 2, comprising increase rate detection means for detecting an increase rate of at least one of the first signal and the second signal; wherein the fire detection condition is changed based on the discrimination result by the discriminating means and the increase rate by the increase rate detection means, characterized by a fire detection device.

4. The fire detection device according to claim 3, The fire detection condition is changed so that when the type of the detection target is identified as a fire detection target by the identification means and the increase rate detected by the increase rate detection means satisfies a predetermined increase rate threshold condition, the fire detection means is more likely to detect a fire than before the change. A fire detection device characterized by this.

5. A fire detection device according to any one of claims 1 to 4, wherein the fire detection means detects a fire when at least one of the first signal and the second signal satisfies a predetermined threshold condition, or when at least one of the first signal and the second signal satisfies a predetermined threshold condition and a predetermined accumulation condition is satisfied, wherein the fire detection condition is made easier to detect a fire than before the change by making at least one of the threshold condition and the accumulation condition looser than before the change, A fire detection device characterized in that at least one of the threshold condition and the accumulation condition is made stricter than before the change, making it more difficult to detect a fire than before the change.

6. It is a device that detects signals associated with the optical action of the detection target in the monitoring area by at least a first optical setting and a second optical setting, and includes a signal detection means for detecting a first signal obtained by the first optical setting and a second signal obtained by the second optical setting, an identification means for identifying, as the type of the detection target, a fire detection target and a non-fire detection target based on the first signal and the second signal detected by the signal detection means, and for identifying white smoke and black smoke as the type of the fire detection target, a fire detection means for detecting a fire when a predetermined fire detection condition is satisfied based on at least one of the first signal and the second signal detected by the signal detection means, and is provided with wherein the fire detection condition is changed so that when white smoke is identified as the fire detection target by the identification means, it is easier to detect a fire than the fire detection condition initially set by the fire detection means, when black smoke is identified as the fire detection target by the identification means, it is changed so that it is easier to detect a fire than the fire detection condition after the change associated with the identification of white smoke by the fire detection means, A disaster prevention facility characterized in that when a non-fire detection target is identified by the identification means, it is changed so that it is more difficult to detect a fire than the fire detection condition initially set by the fire detection means.

7. A disaster prevention facility according to claim 6, It is provided with an increase rate detection means for detecting an increase rate of at least one of the first signal and the second signal. The fire detection condition is a disaster prevention facility characterized in that it is changed based on the identification result by the identification means and the increase rate by the increase rate detection means. **Claim 8** The disaster prevention facility according to claim 7, It is provided with a receiver and a sensor that detects a fire and transmits a fire signal to the receiver. The sensor is characterized in that it is provided with the signal detection means, the identification means, and the fire detection means, or the signal detection means, the identification means, the fire detection means, and the increase rate detection means. **Claim 9** The disaster prevention facility according to claim 7, It is provided with a receiver and a sensor that detects a fire and transmits a fire signal to the receiver. The sensor is provided with the signal detection means. The receiver is characterized in that it is provided with the identification means and the fire detection means, or the identification means, the fire detection means, and the increase rate detection means. **Claim 10** A fire detection method for detecting a fire in a monitoring area, By signal detection means, signals associated with the light action of a detection target in the monitoring area are detected by at least a first optical setting and a second optical setting, and a first signal obtained by the first optical setting and a second signal obtained by the second optical setting are detected. By an identification means, based on the first signal and the second signal detected by the signal detection means, the types of the detection target are identified as a fire detection target and a non-fire detection target, and the types of the fire detection target are identified as white smoke and black smoke. By fire detection means, when a predetermined fire detection condition is satisfied based on at least one of the first signal and the second signal detected by the signal detection means, a fire is detected. The fire detection condition is When white smoke is identified as the fire detection target by the identification means, it is changed so that it is easier to detect a fire than the fire detection condition initially set by the fire detection means. When black smoke is identified as the fire detection target by the identification means, it is changed so that it is easier to detect a fire than the fire detection condition after the change associated with the identification of white smoke by the fire detection means. When a non-fire detection target is identified by the identification means, it is changed so that it is more difficult to detect a fire than the fire detection condition initially set by the fire detection means. This is a fire detection method characterized by this. **Claim 11** A fire detection method according to claim 10, comprising: detecting an increase rate of at least one of the first signal and the second signal by an increase rate detection means; changing the fire detection condition based on the identification result by the identification means and the increase rate by the increase rate detection means.

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