Smoke sensor

Abstract

To provide a smoke sensor capable of appropriately determining whether or not a concentration of smoke exceeds a predetermined threshold regardless of whether or not sounding means such as a speaker is operating.SOLUTION: A smoke sensor 100 comprises: smoke sensing means 2 for detecting smoke; sounding means 3 which generates sound during operation; sounding determination means 4 for determining whether or not the sounding means 3 is operating; and control means 1 for controlling a warning operation by determining whether or not a smoke concentration exceeds a threshold based on a predetermined determination method. The control means 1 detects the concentration from smoke detected by the smoke sensing means 2, changes the determination method of the smoke concentration depending on whether the sounding means 3 is operating or not based on a determination result of the sounding determination means 4, and determines whether one or more of detected concentrations, detected within a predetermined period, exceed a predetermined threshold in the case where the sounding means 3 is operating.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a smoke detector.

Background Art

[0002] Conventionally, a smoke detector has been used to monitor the concentration of smoke indoors such as in a house and report it to users or the like to prompt countermeasures or evacuation when the concentration exceeds a certain level. The smoke detector is also used as a determination means for various alarms such as a fire alarm, and is further used in a composite alarm including a means for detecting toxic gases such as carbon monoxide. In such a smoke detector, the smoke flowing into the housing from an inlet provided on its side surface or the like is introduced into a smoke detection space between a light emitting part and a light receiving part, and the light traveling from the light emitting part through the detection space toward the light receiving part is scattered by the introduced smoke, and the concentration of the smoke is detected by detecting the scattered light corresponding to the concentration of the smoke at the light receiving part (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In many cases, various alarms such as a single smoke detector or a fire alarm including a smoke detector are provided with a sounding means to acoustically report the occurrence of a detected abnormal situation such as a fire or a gas leak to users or the like. For example, since a speaker can emit not only a monotonous warning sound but also a voice including information such as a specific abnormal situation and countermeasures, as the functionality and control variety of alarms progress, the spread of alarms equipped with speakers is advancing.

[0005] However, in alarm devices, including smoke detectors, that are equipped with sound-emitting means such as speakers, the vibration of air caused by the operation of the speaker can hinder the introduction of smoke from outside the alarm device to the detection space. In particular, if the sound-emitting means such as a speaker and the smoke introduction path from the smoke intake to the detection space are arranged in close proximity to meet the demand for miniaturization of alarm devices, spatial separation of the two becomes difficult, and the impact of the speaker's operation on smoke introduction is likely to increase. If the proper introduction of smoke is hindered, it may result in situations where alarms based on smoke concentration, such as fire alarms, are not promptly issued, even if the area around the alarm device is filled with smoke at a concentration high enough to be judged as abnormal.

[0006] In view of these problems, the present invention aims to provide a smoke detector that can appropriately determine whether the smoke concentration exceeds a predetermined threshold, regardless of whether or not the sound-emitting means, such as a speaker, installed inside the detector is operating. [Means for solving the problem]

[0007] The smoke detector of the present invention comprises a smoke detection means for detecting smoke, a sound-emitting means for emitting sound when in operation, a sound-emitting determination means for determining whether the sound-emitting means is in operation, and a control means for determining whether the smoke concentration exceeds a threshold based on a predetermined determination method and controlling the alarm operation. The control means detects the concentration from the smoke detected by the smoke detection means, changes the determination method based on the determination result of the sound-emitting determination means depending on whether the sound-emitting means is in operation or not, and, if the sound-emitting means is in operation, determines whether one or more of the detected concentrations detected within a predetermined period exceed the threshold.

[0008] The control means may determine whether the detected concentration detected at a predetermined timing exceeds the threshold when the sound-producing means is not operating.

[0009] The control means may determine that the smoke concentration exceeds the threshold if the detected concentration detected at the predetermined timing exceeds the threshold a predetermined number of times when the sound-generating means is not operating.

[0010] The control means may determine that the smoke concentration exceeds the threshold if, when the sound-emitting means is operating, one or more of the detected concentrations detected within a predetermined period exceeds the threshold, or if, when the sound-emitting means is not operating, the control means may determine that the smoke concentration exceeds the threshold if the detected concentrations detected at the predetermined timing exceed the threshold multiple times in a row.

[0011] The control means may, when the sound-emitting means is not operating, detect the concentration from the smoke detected by the smoke-sensing means at regular intervals, and when the sound-emitting means is operating, detect the concentration from the smoke detected by the smoke-sensing means at intervals shorter than the regular intervals.

[0012] The smoke detector of the present invention may further include a CO detection means for detecting the carbon monoxide concentration, and the control means controls the alarm operation by determining whether the carbon monoxide concentration exceeds a threshold based on a predetermined determination method, and the method for determining whether the carbon monoxide concentration exceeds a threshold may be the same whether the sound-emitting means is operating or not.

[0013] The smoke detector of the present invention may further include a storage means for storing all or the maximum value of the detected concentrations within the predetermined period.

[0014] The smoke detector of the present invention may further include a storage means for storing information on whether or not the sound-emitting means is operating. [Effects of the Invention]

[0015] According to the present invention, a smoke detector is provided that can appropriately determine whether the smoke concentration exceeds a predetermined threshold, regardless of whether or not a sound-emitting means such as a speaker installed inside is operating.

Brief Description of Drawings

[0016] [Figure 1] It is a block diagram showing an example of the configuration of a smoke detector according to an embodiment of the present invention. [Figure 2] It is a perspective view showing an example of an alarm including a smoke detector according to an embodiment of the present invention. [Figure 3] It is a schematic diagram showing the state of gas flow inside the housing in the alarm of FIG. 2. [Figure 4] It is a timing diagram showing an example of concentration determination during non-sounding according to an embodiment of the present invention. [Figure 5] It is a timing diagram showing an example of concentration determination during rising smoke concentration during sounding according to an embodiment of the present invention. [Figure 6] It is a timing diagram showing an example of concentration determination during falling smoke concentration during sounding according to an embodiment of the present invention. [Figure 7A] It is a flowchart showing an example of the operation of a smoke detector during non-sounding according to an embodiment of the present invention. [Figure 7B] It is a flowchart showing an example of the operation of a smoke detector during sounding according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0017] Hereinafter, a smoke detector according to an embodiment of the present invention will be described with reference to the accompanying drawings. However, the embodiments and the accompanying drawings described below merely show an example of the smoke detector according to the present invention. The configuration and operation of the smoke detector according to the present invention are not limited to the configuration and operation illustrated in the embodiments and the accompanying drawings described below.

[0018] <Basic Configuration> FIG. 1 shows, in a block diagram, the main components of a smoke detector 100 according to an embodiment of the present invention. The smoke detector 100 monitors the environment around the installation location of the smoke detector 100, such as indoors in a residence or various buildings, and performs an alarm operation to notify the user by light, sound, etc. when it is determined that the concentration of the surrounding smoke is equal to or higher than a predetermined threshold value.

[0019] As shown in FIG. 1, the smoke detector 100 of the present embodiment includes a smoke detection means 2 for detecting smoke, a sound generation means 3 that emits sound during operation, a sound generation determination means 4 for determining whether the sound generation means 3 is operating, and a control means 1 for controlling the alarm operation. The smoke detector 100 in the example of FIG. 1 further includes a storage means 5 and a CO detection means 6 for detecting the concentration of carbon monoxide. The smoke detector 100 has a housing 101, and the housing 101 is provided with the smoke detection means 2, the sound generation means 3, the sound generation determination means 4, the control means 1, the storage means 5, and the CO detection means 6. The storage means 5 stores various information, such as the detected smoke concentration, which is generated and / or used in a series of alarm operations by the smoke detector 100. In the example of FIG. 1, the control means 1 is connected to all the others, that is, the smoke detection means 2, the sound generation means 3, the sound generation determination means 4, the storage means 5, and the CO detection means 6. Therefore, the control means 1 may be able to control all of these other means. Also, the control means 1 may be able to exchange information possessed by each means and signals generated by each means with all of these other means. In the example of FIG. 1, the smoke detection means 2 and the storage means 5 are also connected to each other. In addition, the sound generation determination means 4 and the sound generation means 3 may be connected via a medium such as a sound wave, which is, for example, a vibration of a gas, to convey that the sound generation means 3 is emitting sound, as shown by the dashed arrow.

[0020] Control means 1 detects the concentration of smoke from the smoke detected by smoke sensing means 2. That is, control means 1 detects the concentration of smoke in the gas currently surrounding smoke sensing means 2 in its vicinity. In addition, control means 1 is configured to determine whether the smoke concentration in the environment in which smoke detector 100 is installed exceeds a threshold based on a predetermined determination method (hereinafter, this determination method will also be simply referred to as the "concentration determination method"). In the following, in order to make the distinction clear with concise terminology, the smoke concentration in the environment in which smoke detector 100 is installed, which should be monitored by smoke detector 100, will be simply referred to as the "ambient concentration," and the concentration of smoke that control means 1 actually detects from the smoke detected by smoke sensing means 2 will be simply referred to as the "detected concentration."

[0021] In this embodiment, the control means 1 determines whether the sound-producing means 3 is operating based on the determination result of the sound-producing means 4, and changes the concentration determination method depending on whether the sound-producing means 3 is operating or not. The control means 1 is configured to determine whether at least one of the one or more detected concentrations detected by the control means 1 within a predetermined period exceeds a predetermined threshold when the sound-producing means 3 is operating. In this embodiment, when the sound-producing means 3 is operating, the control means 1 determines whether at least one of the detected concentrations detected from the smoke detected by the smoke-sensing means 2 within a predetermined period exceeds a predetermined threshold. Therefore, as will be described in detail below, even in situations where smoke is difficult to reach the detectable area of ​​the smoke-sensing means 2 due to the operation of the sound-producing means 3, it is possible to appropriately determine whether the ambient concentration exceeds a predetermined threshold and promptly inform the user.

[0022] <Each component and basic operation of the smoke detector> The smoke detection means 2 senses smoke in the space surrounding it, specifically smoke in the smoke detection area within the smoke detection means 2 that is in communication with the surroundings, and outputs a detection result in the form of an electrical signal (voltage or current) of a magnitude corresponding to the amount of smoke, i.e., the concentration of smoke in the smoke detection area. Therefore, the smoke detection means 2 outputs a detection result corresponding to the concentration of smoke that has flowed into the smoke detection area of ​​the smoke detection means 2 from the surroundings of the smoke detector 100 along with the surrounding air. Other examples of smoke detection means 2 include a photoelectric spot-type detection mechanism, but the smoke detection means 2 is not limited to this.

[0023] For example, in a photoelectric spot-type detection mechanism, a light-emitting element that emits light toward the smoke detection area is provided, and a light-receiving element that receives light propagating within the smoke detection area is provided at a position offset from the optical axis of the light-emitting element, separated from the light-emitting element by a light-shielding wall. When smoke is present in the smoke detection area, the light from the light-emitting element is scattered to an extent corresponding to the density of smoke in the smoke detection area, and this scattered light is received by the light-receiving element. The light-receiving element then outputs an output signal (sensing signal), such as voltage or current, with a magnitude corresponding to the amount of scattered light it received, i.e., corresponding to the density of smoke. In a photoelectric separated-type detection mechanism, a light-emitting element and a light-receiving element similar to those in the photoelectric spot type are provided facing each other on the optical axis, and the light, weakened to an extent corresponding to the density of smoke in the smoke detection area, is received by the light-receiving element. The light-receiving element then outputs a sensing signal with a magnitude corresponding to the density of smoke based on the received light.

[0024] As shown in Figure 1, the smoke detection means 2 is connected to the control means 1, and the output of the smoke detection means 2 is input to the control means 1. The information obtained from the output result of the smoke detection means 2 input to the control means 1 may be stored in the storage means 5. In the example in Figure 1, the smoke detection means 2 and the storage means 5 are connected, so the detection result of the smoke detection means 2 may be sent directly from the smoke detection means 2 to the storage means 5.

[0025] The sound-emitting means 3 can be any element capable of emitting sound according to control information, such as an electrical signal from outside the sound-emitting means 3. Examples of sound-emitting means 3 include a speaker capable of emitting sounds of any frequency and volume, and a buzzer that emits monotonous continuous or intermittent sounds, but the sound-emitting means 3 is not limited to these. When operating, the sound-emitting means 3 emits sound by vibrating a gas, such as the surrounding air. That is, the sound-emitting means 3 can emit any sound by vibrating when operating. The sound-emitting means 3 can emit an alarm sound when the smoke detector 100 issues an alarm regarding the detection of smoke. For example, if the sound-emitting means 3 is a speaker, the sound-emitting means 3 may emit an alarm sound along with a message prompting appropriate action such as evacuation or ventilation. In addition, the sound-emitting means 3 may emit an alarm sound for any alarm other than the smoke detection alarm, such as an alarm sound for carbon monoxide gas detection or a message prompting ventilation, and may emit any notification sound or notification message under circumstances other than the alarm activation situation. For example, when detecting a fire based on the detection of smoke above a predetermined concentration, and / or when detecting an abnormal condition based on the ambient temperature and humidity, such as flammable gas above a predetermined concentration, excessively high temperature, or low humidity, and when notifying the battery level or the results of a self-inspection, the sound-emitting means 3 may emit sounds or voices appropriate to each condition. The operation of the sound-emitting means 3 may be controlled by the control means 1, or by any component of the smoke detector 100 other than the control means 1.

[0026] As described above, the control means 1 detects the concentration (detected concentration) of smoke detected by the smoke detection means 2 and controls the alarm operation. For example, the control means 1 has a calibration curve between the detection signal output from the smoke detection means 2 and the smoke concentration, and uses this calibration curve to detect the detected concentration based on the signal currently input from the smoke detection means 2. Furthermore, it determines whether the detected concentration exceeds a predetermined threshold. Then, based on the determination result for the detected concentration and the concentration determination method, it determines whether the ambient concentration exceeds a predetermined threshold.

[0027] The control means 1 may be configured to control not only the ambient concentration but also the entire alarm operation of the smoke detector 100. For example, the control means 1 may control the sensing operation of the smoke sensing means 2, such as the intensity and emission timing of the light for smoke detection and the timing of the output of the sensing signal, or it may control the operation of the sounding means 3, such as the sounding timing, volume, frequency, duration of sounding, and the content of the message to be emitted. The control means 1 may also control the storage means 5, for example, the operation of writing various types of information to and reading from the storage means. For example, the control means 1 may select the information to be written to the storage means 5 and the information to be read from the storage means 5, or it may select the memory space (address) within the storage means 5 that is the target of writing and reading.

[0028] Furthermore, control means 1 may control the operation of CO detection means 6. Similar to the control of smoke detection means 2 described above, control means 1 may control, for example, the timing of carbon monoxide gas detection and the timing of output of the detection signal in CO detection means 6. Furthermore, control means 1 may control the judgment operation of sound judgment means 4. For example, the timing of the judgment of whether or not sound is produced by sound judgment means 2 may be controlled by control means 1, and the judgment criteria of sound judgment means 4 may be provided from control means 1 to sound judgment means 4. Also, if control means 1 is controlling the operation of sound judgment means 3, information for determining whether or not sound is produced, and electrical signals such as voltage or current indicating that information may be provided from control means 1 to sound judgment means 4.

[0029] The control means 1 may consist of hardware such as a semiconductor device like a microcontroller or ASIC, and its peripheral components. The control means 1 may also consist of this hardware and software such as a control program that operates the semiconductor device like the microcontroller or ASIC in a predetermined procedure. Such software may be built into the hardware constituting the control means 1, or it may be stored in the storage means 5. The control means 1 may have calculation functions, comparison functions, memory functions, and timing functions to control the entire alarm operation, from monitoring the surrounding environment by the smoke detection means 2 to issuing an alarm by the sound-emitting means 3, etc. For example, a sound-emitting determination means 4 may be built into the semiconductor device constituting the control means 1.

[0030] As mentioned above, the storage means 5 stores various types of information, such as detected concentrations. The storage means 5 may store all detected concentrations themselves, which are detected at any given time by the control means 1, or it may store statistical values, such as the maximum value, minimum value, mean, median, and mode, which are the result of statistical processing of multiple detected concentrations detected over a certain period by the control means 1. The storage means 5 may also store information on whether the sound generation means 3 is operating, which is determined by the sound generation determination means 4 or is known by the control means 1 itself. Various memory devices such as random access memory (RAM) are exemplified as storage means 5, but any memory element capable of writing and reading information such as detected concentrations can be used as storage means 5. Furthermore, storage means 5 may be included in the control means 1, in which case storage means 5 may be RAM, various registers, or various identification flags set in a memory space such as registers or memory, which are built into a microcontroller that mainly constitutes the control means 1.

[0031] The sound generation determination means 4 determines whether the sound generation means 3 is operating, that is, whether the sound generation means 3 is vibrating and emitting sound. For example, if the control means 1 sends a control signal for the operation of the sound generation means 3, that control signal is monitored by the sound generation determination means 4. If the voltage or current constituting the control signal is above or below a predetermined value, it is determined that the sound generation means 3 is operating or not operating. Therefore, the sound generation determination means 4 may be a voltage or current comparison element such as a comparator. Also, if the sound generation determination means 4 is included in the control means 1, the sound generation determination means 4 may be a comparison function of a semiconductor device such as a microcontroller that constitutes the control means 1. Furthermore, if the control means 1 or the storage means 5 is provided with an identification flag (for example, the sound generation identification flag Fs described later (see Figure 5)) that indicates whether the sound generation means 3 is operating with two logical values ​​(such as a high level and a low level), the sound generation determination means 4 may be a logic gate element to which the logical value of that identification flag is input.

[0032] The CO detection means 6 detects the presence, preferably its concentration, of carbon monoxide in the surrounding environment. Examples of CO detection means 6 include any type of carbon monoxide sensor such as semiconductor, electrochemical, catalytic combustion, or non-dispersive infrared sensors, but the CO detection means 6 is not limited to the above types of carbon monoxide sensors, as long as it is capable of detecting the presence of carbon monoxide at least above a certain concentration. In the example in Figure 1, the CO detection means 6 outputs the detection result, which may be an electrical signal, to the control means 1. In addition to controlling alarms related to smoke, the control means 1 may determine, based on a predetermined determination method, whether the detected carbon monoxide concentration exceeds a predetermined threshold for carbon monoxide, and control the alarm operation related to carbon monoxide based on the determination result. The smoke detector 100 may also include, in addition to the CO detection means 6, or in place of the CO detection means 6, a flammable gas detection means, a temperature detection means, and / or a humidity detection means. In that case, the control means 1 may control the alarm operation related to the detection target of each of these detection means.

[0033] Figure 2 shows an example of the appearance of an alarm 200 including the smoke detector 100 of this embodiment. The alarm 200 may be a fire alarm that detects the occurrence of a fire and issues an alarm based on the concentration and temperature of smoke in the surroundings. The alarm 200 may also be a composite alarm that detects carbon monoxide gas and other flammable gases, or detects the intrusion of an outsider into the building and issues an alarm. As shown in Figure 2, in the alarm 200, the components of the smoke detector 100, such as the smoke sensing means 2 and the sounding means 3, are housed in a housing 201. Although not shown in Figure 2, the housing 201 also houses other components of the smoke detector 100 (for example, the sounding determination means 4 and control means 1 illustrated in Figure 1). The housing 201 has openings 202 and 203 that communicate with the inside of the housing.

[0034] The opening 202 extends across the entire side of the housing 201 and functions as an intake for drawing in air, such as surrounding air, near each detection element inside the alarm 200. The opening 203 is formed in the housing 201 opposite the sound-emitting means 3, and the sound emitted from the sound-emitting means 3 is mainly released to the outside through the opening 203. The sound-emitting means 3 emits sound when smoke is detected at a concentration above a predetermined threshold, when a fire is detected based on that, and / or when carbon monoxide gas is detected at a concentration above a predetermined value. In addition, as mentioned above, when abnormal conditions based on ambient temperature and humidity such as flammable gas at a concentration above a predetermined level or excessively high or low humidity are detected, and when notifying the battery level or the results of self-inspections, the sound-emitting means 3 may also emit sounds or voices appropriate to each condition toward the outside of the alarm 200.

[0035] Figure 3 schematically shows the flow of gas, such as air, inside the housing 201 of the alarm device 200 in Figure 2. Air flowing into the housing 201 from the opening 202 flows into the smoke detection area 22 inside the housing through the smoke intake port 21 provided in the smoke detection means 2. If the gas flowing into the smoke detection area 22 contains smoke S, the smoke S is detected by the smoke detection means 2, and its concentration is detected by the control means 1 (see Figure 1).

[0036] However, when the sound-emitting means 3 is activated, the vibration of the air caused by the sound-emitting means 3 may affect the airflow from outside the alarm 200 to the smoke-sensing means 2 in the vicinity of the smoke-sensing means 2 and around the smoke detector 100 or alarm 200. In particular, the flow of smoke S, which may exist in particulate form in the gas heading toward the smoke-sensing means 2, may be obstructed to a greater extent than the surrounding gas. For example, in the example in Figure 3, it is thought that smoke S flowing in from below the sound-emitting means 3 is easily affected by the operation of the sound-emitting means 3. In addition, since the sound emitted from the sound-emitting means 3 can be repeatedly reflected off the inner wall of the housing 201, it is thought that the flow of smoke S flowing in from any direction may also be obstructed. In particular, as the alarm 200 is miniaturized, it becomes difficult to spatially separate the flow path from the smoke-sensing means 2 to the gas flowing into the alarm 200 or the smoke detector 100 from the sound-emitting means 3, making it difficult to prevent the operation of the sound-emitting means 3 from affecting the flow of smoke. Even if a partition or the like is provided between the smoke passage and the sound-emitting means 3, if the partition vibrates due to sound waves from the sound-emitting means 3, a sufficient preventative effect may not be obtained.

[0037] When the flow of smoke is obstructed, the smoke concentration in the smoke detection area 22, which should ideally be at a similar level to the smoke concentration around the smoke detector 100 or the alarm 200, becomes unstable, and the smoke detector 100 may not properly detect the smoke concentration in its surrounding environment. Specifically, when the flow of smoke to the smoke detection means 2 is obstructed, the smoke detector 100 is thought to detect a lower smoke concentration than the actual smoke concentration around the smoke detector 100. As a result, even though the monitoring area of ​​the smoke detector 100 is actually filled with smoke at a concentration exceeding a predetermined threshold, it is possible that a smoke concentration-based alarm, such as a fire alarm, may not be issued in a timely manner.

[0038] In this regard, if smoke detection is performed continuously in the smoke detector 100, even if the detected smoke concentration becomes unstable due to the operation of the sound-emitting means 3, the smoke flowing into the smoke detection area 22 between gas vibrations can be captured and its concentration detected, potentially allowing a predetermined alarm to be issued without significant delay. However, if the light-emitting element and light-receiving element are kept constantly operating in the photoelectric smoke detection means 2 described above to continuously detect smoke, the power consumption of the smoke detector 100 is likely to increase unnecessarily. In particular, if the alarm 200 is battery-powered, such power waste is highly undesirable. Therefore, it is preferable to detect or determine the smoke concentration at intervals long enough to issue an alarm within a delay time stipulated by, for example, legal regulations.

[0039] Therefore, in the smoke detector 100 of this embodiment, as described above, the control means 1 is configured to change the concentration determination method depending on whether the sound-emitting means 3 is operating or not. When the sound-emitting means 3 is operating, that is, under conditions where the flow of smoke to the smoke detection means 2 is easily obstructed, the control means 1 determines whether one or more of the detected concentrations detected within a predetermined period exceeds a predetermined threshold. For example, when the sound-emitting means 3 is operating, the control means 1 detects one or more smoke concentrations (detected concentrations), preferably multiple, at time intervals shorter than the length of the predetermined period, and determines whether any of the preferably multiple detected concentrations detected within the predetermined period exceeds a predetermined threshold. The control means 1 then determines that the ambient concentration exceeds a predetermined threshold if at least one of the one or more detected concentrations exceeds the predetermined threshold for each predetermined period. In other words, the control means 1 determines that the ambient concentration exceeds a predetermined threshold even if only the maximum value among the one or more detected concentrations exceeds the predetermined threshold. Therefore, in this embodiment, even if the smoke concentration within the smoke detection area 22 is unstable, it is possible to determine more reliably that the ambient concentration exceeds a predetermined threshold compared to the case where the smoke concentration is detected in a predetermined surrounding area and it is determined whether or not it exceeds a threshold.

[0040] Furthermore, since the operation of the sound-emitting means 3 has little effect on the determination of ambient concentration, the sound-emitting means 3 and the smoke-sensing means 2 can be placed in close proximity, which can simplify the shape of the housing 201 or enable the realization of a smaller smoke detector 100.

[0041] On the other hand, if the sound-emitting means 3 is not operating, a determination is made as to whether the ambient concentration exceeds a predetermined threshold based on a concentration determination method different from the above concentration determination method. For example, if the sound-emitting means 3 is not operating, the control means 1 detects the smoke concentration at a predetermined timing and determines whether the detected concentration exceeds a predetermined threshold. For example, the smoke concentration is detected at the above predetermined intervals, and it is determined whether the detected concentration exceeds a predetermined threshold. In this case, smoke concentration detection is not performed at time intervals shorter than the above predetermined interval. Therefore, even if the sound-emitting means 3 is not operating, that is, even if the flow of smoke to the smoke detection area 22 is not easily obstructed, it is possible to avoid the unnecessary consumption of a lot of power due to frequent detection of smoke concentration. Thus, according to this embodiment, it is possible to appropriately determine whether the ambient concentration exceeds a predetermined threshold, regardless of whether the sound-emitting means 3 is operating, while avoiding unnecessary power consumption.

[0042] <Method for determining concentration based on the presence or absence of operation of the sound-producing means> Referring to Figures 4 to 6, the concentration determination method in the smoke detector of this embodiment will be further explained. Figure 4 shows an example of the operation of the smoke detector of this embodiment based on the concentration determination method when the sound-emitting means 3 (see Figure 1) is not operating, as shown in a timing diagram. In Figure 4, the ambient concentration Ca is shown by a solid line at the top, and a predetermined threshold Cth, which is the criterion for deciding whether or not to issue an alarm, such as a fire alarm, based on the smoke concentration, is shown by a dashed line. Immediately below the ambient concentration Ca, the timing of smoke detection by the smoke detection means 2 (see Figure 1) and the timing of detection of the detected smoke concentration by the control means 1 (see Figure 1) are shown by smoke detection pulses Pd. When the smoke detection pulse Pd is generated, for example, the light-emitting element and the light-receiving element in the smoke detection means 2 operate to detect smoke in the smoke detection area 22 (see Figure 3), and the smoke concentration is detected by the control means 1. Immediately below the smoke detection pulse Pd, the timing of concentration determination by the control means 1 based on the concentration determination method is shown by determination pulse Pj. When a judgment pulse Pj is generated, it is determined whether the detected smoke concentration exceeds the threshold Cth. If it does, the ambient concentration Ca is considered to have exceeded the threshold Cth, and an alarm, such as a fire alarm, is issued.

[0043] In the example shown in Figure 4, as indicated by the smoke detection pulse Pd and the determination pulse Pj, the control means 1 determines the detected smoke concentration each time the smoke concentration detected by the smoke sensing means 2 is detected by the control means 1. The detection of smoke concentration and the determination of the detected concentration by the control means 1 are performed synchronously at predetermined timings, and in the example shown in Figure 4, these detections and determinations are performed periodically at a predetermined period P1. Thus, when the sound generation means 3 is not operating, the control means 1 may detect the concentration from the smoke detected by the smoke sensing means 2 at a fixed period.

[0044] Furthermore, immediately below the determination pulse Pj shown in Figure 4, there is an alarm state Sa, which is indicated by a binary value of low and high levels, indicating whether or not an alarm based on smoke concentration, such as a fire alarm, has been issued. A low-level alarm state Sa indicates that no alarm based on smoke concentration has been issued, while a high-level alarm state Sa indicates that an alarm based on smoke has been issued. If it is determined that the ambient concentration Ca exceeds a predetermined threshold Cth, a sound may be emitted by the sound-emitting means 3 as a fire alarm, for example. However, since Figure 4 shows the concentration determination method when the sound-emitting means 3 is not operating, even if an alarm based on smoke concentration is issued, the sound-emitting means 3 will not operate and the alarm will be emitted by other alarm means such as light.

[0045] Immediately below the alarm state Sa, the timing of carbon monoxide detection by the CO detection means 6, and the timing of determining whether the detected carbon monoxide concentration exceeds a predetermined threshold (not shown), are further indicated by the CO detection / determination pulse Pco. When the CO detection / determination pulse Pco occurs, the CO detection means 6 detects the presence and concentration of carbon monoxide, and determines whether the detected concentration exceeds the predetermined threshold. Then, an alarm regarding carbon monoxide is issued according to the determination result. In the example in Figure 4, carbon monoxide detection and determination of its concentration are performed by the CO detection means 6 at a fixed predetermined period P2. In the example in Figure 4, the predetermined period P2 is shorter than the predetermined period P1 in which the smoke concentration is detected and determined, but the predetermined period P2 may be longer than the predetermined period P1, or it may be the same as the predetermined period P1.

[0046] In Figure 4, smoke concentration is detected at time points T1 and T2, and it is determined whether or not it exceeds the threshold Cth. However, at these times, no fire or other incidents have occurred, and the ambient concentration Ca remains stable and below the threshold Cth. Therefore, as indicated by the activation state Sa, no fire alarms or other alarms based on smoke concentration have been issued.

[0047] Subsequently, a fire occurs at time T3, and the ambient concentration Ca begins to rise, exceeding the threshold Cth at time T4. Since time T4 is not a time for smoke concentration detection and determination, no fire alarm is issued at time T4. However, at time T5, which is the next time for smoke concentration detection and determination, smoke with a concentration exceeding the threshold Cth is detected by the smoke detection means 2, and this concentration is detected as the detected concentration by the control means 1. It is then determined whether the detected concentration exceeds a predetermined threshold Cth, and since the detected concentration exceeds the threshold Cth, an alarm based on smoke concentration, such as a fire alarm, is issued at time T5, as indicated by the alarm state Sa. At time T6, the next time for smoke concentration detection and determination after time T5, the ambient concentration Ca is still above the threshold Cth, so the alarm continues.

[0048] Figure 4 shows an example where the carbon monoxide concentration is below the threshold for carbon monoxide concentration. Therefore, although the CO detection means 6 repeatedly detects carbon monoxide and determines its concentration at a predetermined cycle P2, no alarm regarding carbon monoxide is issued.

[0049] In the example shown in Figure 4, as described above, if it is determined that the detected concentration exceeds a predetermined threshold Cth at time T5, an alarm is immediately issued at time T5. However, even when the sound-emitting means 3 is not operating, the smoke concentration in the smoke detection area 22 may temporarily increase due to, for example, cigarette smoke, and by detecting this smoke concentration, it may be mistakenly determined that the ambient concentration Ca exceeds the threshold Cth. In that case, a false alarm will be issued by the alarm 200 (see Figure 2).

[0050] To avoid such false alarms, the control means 1 may be configured to determine that the ambient smoke concentration Ca exceeds a predetermined threshold Cth if the detected concentration detected at a predetermined timing exceeds a predetermined threshold Cth for a predetermined number of times when the sound-emitting means 3 is not operating. By doing so, it may be possible to prevent false alarms caused by temporary or instantaneous increases in smoke concentration. The predetermined number of times is preferably multiple numbers, such as two or three. For example, if the predetermined number of times is two, in the example in Figure 4, an alarm based on smoke concentration is issued at time T6, not at time T5.

[0051] Furthermore, if the sound-emitting means 1 is not operating, the control means 1 may be configured to determine that the ambient smoke concentration Ca exceeds a predetermined threshold Cth if the detected concentration detected at a predetermined timing exceeds a predetermined threshold Cth multiple times in a row, in order to avoid the above false alarm. For example, since the concentration of smoke generated by a fire is unlikely to decrease immediately after exceeding the threshold Cth, determining in this way may also prevent false alarms caused by a temporary or instantaneous increase in smoke concentration.

[0052] Figure 5 shows an example of the operation of the smoke detector of this embodiment based on the concentration determination method when the sound-emitting means 3 (see Figure 1) is operating, as shown in a timing diagram. In Figure 5, the top row shows the sound-emitting state Ss, which indicates whether or not the sound-emitting means 3 is operating, using two values: low level and high level. A low-level sound-emitting state Ss indicates that the sound-emitting means 3 is not operating, i.e., no sound is being emitted, while a high-level sound-emitting state Ss indicates that the sound-emitting means 3 is operating, i.e., sound is being emitted. Immediately below the sound-emitting state Ss, similar to Figure 4, the ambient concentration Ca is shown by a solid line, and a predetermined threshold Cth is shown by a dashed line. Furthermore, along with the ambient concentration Ca, the smoke concentration Cd within the smoke-detecting region 22 (see Figure 3) is also shown by a dashed line. Since the smoke concentration within the smoke-detecting region 22 is the detection concentration detected by the control means 1 (see Figure 1), the smoke concentration Cd within the smoke-detecting region 22 will also be referred to as the "detection concentration Cd" below. Below the ambient concentration Ca, the smoke detection pulse Pd, the judgment pulse Pj, the alarm state Sa, and the CO detection / judgment pulse Pco are shown in order, similar to Figure 4.

[0053] In Figure 5, as indicated by the sound emission state Ss, the sound emission means 3 starts operating and emits sound at time T10. The sound emission means 3 may start operating based on sound emission factors other than smoke detection, such as the detection of carbon monoxide or flammable gas at a concentration exceeding a predetermined threshold, or the detection of excessive temperature and humidity. In the example in Figure 5, at time T10, the CO detection / determination pulse Pco detects carbon monoxide at a concentration exceeding a predetermined threshold, and the sound emission means 3 emits a predetermined message or alarm sound to issue an alarm regarding carbon monoxide. As a result of this operation of the sound emission means 3, the flow of smoke into the smoke detection area 22 is obstructed, and from time T10 onward, the smoke concentration Cd in the smoke detection area 22 becomes unstable and fluctuates repeatedly, unable to keep up with the ambient concentration Ca. Therefore, if the control means 1 does not change the concentration determination method and performs smoke concentration detection and determination at a predetermined period P1 as in Figure 4, even though the ambient concentration Ca exceeds a predetermined threshold Cth at time T12, the ambient concentration Ca is not determined to exceed the predetermined threshold Cth until time T15, when the detection concentration Cd exceeds the predetermined threshold Cth when the determination pulse Pj is generated. In other words, although smoke concentration detection and determination are performed at time T13 and time T14, neither the detection concentration Cd at time T13 nor the detection concentration Cd at time T14 exceeds the threshold Cth, so no alarm based on smoke concentration is issued.

[0054] However, as shown by the smoke detection pulse Pd in ​​Figure 5, in this embodiment, when the sound-emitting means 3 starts operating at time T10, the smoke concentration is detected by the control means 1 at a period P3 shorter than the predetermined period P1 used to determine whether the detected concentration Cd exceeds the threshold Cth. As mentioned above, the control means 1 is configured to determine whether one or more of the detected concentrations detected within a predetermined period exceeds a predetermined threshold when the sound-emitting means 3 is operating. In the example in Figure 5, it is determined whether one or more detected concentrations within a predetermined period P1, which is the same length as the predetermined period P1 used for detecting and determining smoke concentration when the sound-emitting means 3 is not operating as shown in Figure 4, exceed the predetermined threshold Cth. If one or more of these detected concentrations exceed the threshold Cth, it is determined that the ambient concentration Ca exceeds the predetermined threshold Cth, and an alarm based on the smoke concentration is issued. Therefore, in the example in Figure 5, regarding the ambient concentration Ca that exceeds the threshold Cth at time T12, an alarm is issued at time T13, as indicated by the alarm state Sa.

[0055] In other words, between time T11, when the judgment pulse Pj occurs before time T13, and time T13, a detection concentration exceeding the threshold Cth is detected at least at time T121. Therefore, even if the detection concentration Cd is below the threshold Cth at time T13, an alarm is issued. For example, as an alarm, a different alarm sound or alarm message may be emitted from the sound-emitting means 3 than that used up to time T13.

[0056] Then, even after the alarm is issued at time T13, as long as the sounding means 3 is operating as indicated by the sounding state Ss, the control means 1 detects the smoke concentration in cycle P3 and determines whether at least one of the detected concentrations within the predetermined period P1 exceeds the threshold Cth. Therefore, even at time T14, which is the time for determining the smoke concentration after time T13, a detected concentration exceeding the threshold Cth is detected at at least time T131 between time T13 and time T14, so the alarm continues even if the detected concentration Cd is below the threshold Cth at time T14. Subsequently, during the period up to time T15, the detected concentration Cd is above the threshold Cth for almost the entire period, so the alarm continues at time T15 as well.

[0057] Thus, in this embodiment, when the sound-emitting means 3 is operating, the control means 1 is configured to determine whether one or more of the detected concentrations detected within a predetermined period exceed a predetermined threshold Cth. Therefore, a smoke-related alarm, such as a fire alarm, can be issued promptly after the threshold Cth at the ambient concentration Ca is exceeded. Furthermore, in order to determine so quickly whether the threshold Cth at the ambient concentration Ca is exceeded, the control means 1 may, when the sound-emitting means 3 is operating, detect the concentration from the smoke detected by the smoke sensing means 2 (see Figure 1) at a shorter period P3 than the fixed period (predetermined period P1) for detecting smoke concentration when the sound-emitting means 3 is not operating.

[0058] In the examples in Figures 4 and 5, the detection frequency of smoke concentration is changed depending on whether the sound-emitting means 3 is operating or not. However, the determination of whether the ambient concentration Ca exceeds a predetermined threshold Cth is made every predetermined period P1 or every predetermined time period P1, and the frequency of this determination remains unchanged. For example, as long as legal regulations are complied with, it may be preferable not to change the frequency of ambient concentration determination in order to prevent an increase in power consumption. Also, in Figure 5, a new predetermined time period P1 is not started when the sound-emitting means 3 starts operating at time T10. Instead, time T13, which is the time when a predetermined time period P1 has elapsed from time T11 (the time when the ambient concentration Ca was determined when the sound-emitting means 3 was not operating), is set as the first time when the ambient concentration Ca is determined after the sound-emitting means 3 starts operating. However, in this embodiment, the control means 1 may start a new predetermined time period P1 from the time it detects the start of operation of the sound-emitting means 3. For example, in Figure 5, whether the ambient concentration exceeds the threshold Cth may be determined every predetermined time period P1 elapsed from time T10 based on the determination of the detected concentration Cd during the predetermined time period P1 relative to the threshold Cth. Therefore, the determination period for ambient concentration Ca may change temporarily before and after the start of operation of the sound generation means 3.

[0059] Examples of a predetermined period (predetermined cycle) P1 include a time of 3 seconds or more and 20 seconds or less, and preferably, the predetermined period (predetermined cycle) P1 may be 6 seconds or more and 12 seconds or less. Examples of a cycle P3 include a time of 0.3 seconds or more and 5 seconds or less, and preferably, the cycle P3 may be 0.5 seconds or more and 2 seconds or less.

[0060] Furthermore, when the sound generation means 3 is operating, it may be possible to suppress the delay in determining whether the threshold has been exceeded at ambient concentration Ca by lowering the threshold Cth without changing the concentration determination method, as in this embodiment. However, simply lowering the threshold Cth may cause an alarm to be issued at ambient concentrations where an alarm should not be issued, or conversely, the alarm may not be stopped at ambient concentrations where it should be stopped. Therefore, in this embodiment, the concentration determination method is changed as described above. In addition, after an alarm regarding smoke is issued at time T13, etc., the threshold Cth may be lowered by an appropriate reduction amount so that the alarm is not repeatedly issued and stopped due to slight fluctuations in ambient concentration.

[0061] Furthermore, in the example shown in Figure 5, an alarm is immediately issued at time T13 if any of the detected concentrations Cd during the predetermined period P1 from time T11 to time T13 exceeds the threshold Cth. In other words, regardless of whether the threshold Cth is exceeded for the detected concentrations Cd during the subsequent predetermined period P1 from time T13 to time T14, the alarm is issued based on the determination for the detected concentration Cd during a single predetermined period P1. On the other hand, when the sound-emitting means 3 is not operating, as mentioned above, it may be preferable to determine whether the threshold Cth is exceeded for the ambient concentration Ca based on the detection concentration Cd exceeding the threshold Cth multiple times.

[0062] However, when the sound-emitting means 3 is operating, as mentioned above, the flow of smoke toward the smoke detection area is easily obstructed by sound waves, and as shown in Figure 5, the detected concentration Cd is unstable and tends to fall below the ambient concentration Ca. For this reason, even when the threshold Cth at the ambient concentration Ca is exceeded based on multiple instances of the threshold Cth at the detected concentration Cd being exceeded when the sound-emitting means 3 is not operating, when the sound-emitting means 3 is operating, it may be preferable to determine that the ambient concentration Ca exceeds the threshold Cth if at least one of the detected concentrations Cd exceeds the threshold Cth within a single predetermined period P1. Thus, in this embodiment, the ambient concentration Ca may be determined to exceed the threshold Cth if one or more of the detected concentrations Cd detected within a single predetermined period P1 exceed the threshold Cth. In addition, in this embodiment, when the sound-emitting means 3 is operating, the ambient concentration Ca may be determined to exceed the threshold Cth if two or more of the detected concentrations Cd exceed the threshold Cth within a single predetermined period P1, or if the detected concentrations Cd continuously exceed the threshold Cth. Doing so may help avoid unnecessary alarms due to accidental increases in smoke concentration.

[0063] In the example in Figure 5, as shown by the CO detection / determination pulse Pco, the predetermined period P2 for detecting the carbon monoxide concentration by the CO detection means 6 (see Figure 1) and determining the carbon monoxide concentration by the control means 1 is not changed between the non-operating and operating states of the sound-emitting means 3 shown in Figures 4 and 5, respectively. That is, in the examples in Figures 4 and 5, the method for determining whether the carbon monoxide concentration exceeds its threshold is not changed according to the operation of the sound-emitting means 3. Thus, the method for determining whether the carbon monoxide concentration exceeds its threshold may be the same whether the sound-emitting means 3 is operating or not. Since the flow of carbon monoxide is less affected by sound waves than smoke, it may be preferable in terms of suppressing an increase in power consumption to not change the method for determining whether the threshold has been exceeded depending on whether the sound-emitting means 3 is operating or not.

[0064] Figure 5 shows, below the CO detection / determination pulse Pco, a sound identification flag Fs indicating whether the sound generation means 3 is operating, a detection concentration write pulse Pw indicating the writing of the detection concentration detected by the control means 1 to the storage means 5 (see Figure 1), and a maximum value update pulse Pr indicating the update of the maximum value of the detection concentration within each predetermined period P1 stored in the storage means 5. The sound identification flag Fs is provided, for example, in the storage means 5 or in a specific storage area of ​​the memory device responsible for the storage function of the control means 1, and is set to a high level ("true (1)") or a low level ("false (0)") when the sound generation means 3 is operating, based on the judgment of the sound generation determination means 4 (see Figure 1), and the opposite when it is not operating. In Figure 5, as indicated by the sound generation state Ss, it is set to a low level when the sound generation means 3 is not operating and to a high level when it is operating. The control means 1 may determine whether the sound generation means 3 is operating or not by referring to the sound identification flag Fs set in the storage means 5 or the control means 1 in this way.

[0065] The detection concentration write pulse Pw indicates that the detection concentration Cd is being written to the storage means 5, and the detection concentration Cd is written to the storage means 5 at the time the detection concentration write pulse Pw occurs. In other words, in the example in Figure 5, the detection concentration write pulse Pw occurs each time a smoke detection pulse Pd occurs, and all of the detection concentrations detected in each predetermined period P1 are stored. The control means 1 may read these stored detection concentrations from the storage means 5 at ambient concentration determination times such as time T13 or time T14, and determine whether any of the detection concentrations Cd exceed the threshold Cth. The detection concentrations stored in the storage means 5 for each predetermined period P1 may be erased after the passage of each predetermined period P1, or they may be overwritten by the detection concentration detected in the next predetermined period P1.

[0066] The maximum value update pulse Pr indicates that the maximum value of the detected concentration Cd during each predetermined period P1 is stored in the storage means 5, and each time a larger detected concentration Cd is detected, the detected concentration Cd stored as the maximum value is updated (overwritten). That is, each time the smoke concentration is detected in period P3, the detected concentration is compared with the detected concentration stored as the maximum value in the storage means 5, and if the detected concentration is larger, the concentration stored as the maximum value is updated. In the example in Figure 5, the concentration stored as the maximum value is updated at the time the maximum value update pulse Pr occurs. For example, at time T111, the detected concentration Cd at time T11, which was stored as the maximum value at time T11, is overwritten by the detected concentration Cd at time T111. Note that the concentration stored as the maximum value is cleared each time the predetermined period P1 has elapsed.

[0067] In this way, the maximum value of the detected concentration Cd during each predetermined period P1 may be stored in the storage means 5. Then, at the ambient concentration determination time, such as time T13 or time T14, the control means 1 may read the concentration stored as the maximum value in this way from the storage means 5 and determine whether the read concentration exceeds the threshold Cth.

[0068] Figure 6, similar to Figure 5, shows a timing diagram illustrating an example of the operation of the smoke detector of this embodiment based on the concentration determination method when the sound-emitting means 3 (see Figure 1) is operating. Figure 6 shows an example of the smoke detector's operation in a situation where the ambient concentration Ca falls below the threshold Cth due to, for example, the spontaneous extinguishing of a small fire, and the smoke alarm is stopped. Figure 6, similar to Figure 5, shows the ambient concentration Ca, detected concentration Cd, threshold Cth, smoke detection pulse Pd, determination pulse Pj, and alarm state Sa, while the sound-emitting state Ss, CO detection / determination pulse Pco, sound-emitting identification flag Fs, detected concentration write pulse Pw, and maximum value update pulse Pr shown in Figure 5 are omitted. In Figure 6, during the period up to time T24, alarms such as fire alarms based on smoke concentration are issued, as indicated by the alarm state Sa.

[0069] In Figure 6, since the sound-emitting means 3 is operating, the detected concentration Cd deviates from the ambient concentration Ca and fluctuates repeatedly. Therefore, in Figure 6, as well, it is determined whether the ambient concentration Ca exceeds the threshold Cth based on the same concentration determination method as described with reference to Figure 5. That is, the control means 1 (see Figure 1) detects the smoke concentration in period P3 and determines that the ambient concentration Ca exceeds the threshold Cth if one or more of the detected concentrations Cd detected within a predetermined period P1 exceeds the threshold Cth. Therefore, although the detected concentration Cd is below the threshold Cth at time T22, in the predetermined period P1 from time T21 to time T22, for example, the detected concentration Cd at time T211 exceeds the threshold Cth, so the alarm continues without being stopped, as indicated by the alarm state Sa. At time T23, although the ambient concentration Ca has already fallen below the threshold Cth at time T222, in the predetermined period P1 from time T22, for example, the detected concentration Cd at time T221 exceeds the threshold Cth, so the alarm is not stopped.

[0070] Subsequently, at time T231, the ambient concentration Ca decreases to a steady state, and at time T24, which is the time for determining the ambient concentration Ca, all detected concentrations Cd during the predetermined period P1 from time T23 are below the threshold Cth. Therefore, as indicated by the activation state Sa, alarms based on smoke concentration, such as fire alarms, are stopped. In Figure 6, the detected concentration Cd continues to fluctuate even after time T24, but the operation of the sound-emitting means 3 may also stop at time T24 when the alarm stops. In that case, the detected concentration Cd is expected to stabilize at approximately the same concentration as the ambient concentration Ca.

[0071] Thus, in the example in Figure 6, when an alarm based on smoke concentration is issued and the sound-emitting means 3 is operating, the control means 1 does not stop the alarm even if a portion of the detected concentrations Cd detected within a predetermined period P1 are below the threshold Cth. In this embodiment, when an alarm based on smoke concentration is issued and the sound-emitting means 3 is operating, the control means 1 may be configured to stop the issued alarm when all of the detected concentrations Cd detected within the predetermined period P1 fall below the threshold Cth. The sounding of the sound-emitting means 3 may obstruct the flow of smoke, which can prevent the issued alarm from being stopped prematurely.

[0072] <Example of the operation flow of the smoke detector of this embodiment> Figures 7A and 7B show flowcharts illustrating an example of the operation of the smoke detector in this embodiment. Figure 7A illustrates the operation of the smoke detector when the sound-emitting means 3 (see Figure 1) is not operating, and Figure 7B illustrates the operation of the smoke detector when the sound-emitting means 3 is operating. In particular, Figure 7A shows an example of the operation of a smoke detector that determines that the ambient concentration exceeds a predetermined threshold when the detected concentration exceeds a predetermined threshold for a predetermined number of times N. In parallel with the operations shown in Figures 7A and 7B, the sound-emitting determination means 4 (see Figure 1) determines whether or not the sound-emitting means 3 is operating, and based on that determination, the control means 1 (see Figure 1) executes the control shown in Figure 7A or Figure 7B.

[0073] As shown in Figure 7A, if the sound-producing means is determined to be inactive (step S0), the count value n, which is counted each time a detection concentration exceeding a predetermined threshold is detected, is cleared (step S1). The count value n is counted, for example, by an element responsible for the memory function or calculation function of the control means 1. The count value n may also be stored in the memory means 5 (see Figure 1) and counted and cleared under the control of the control means 1. Subsequently, in step S2, it is determined whether a predetermined timing for detecting smoke concentration has arrived. For example, it is determined whether a predetermined period P1 (see Figure 4) has elapsed since the previous detection of smoke concentration. If the predetermined timing has not arrived ("N" in step S2), the determination in step S2 is repeated.

[0074] If the predetermined timing has arrived ("Y" in step S2), the smoke concentration detected by the smoke detection means 2 (see Figure 1) is detected (step S3). Next, it is determined whether the detected concentration exceeds a predetermined threshold (step S4). If the detected concentration exceeds the threshold ("Y" in step S4), the count value n is incremented by 1 (step S5), and it is determined whether the count value n has reached a predetermined number of times N (step S6). If the count value n is less than the predetermined number of times N ("N" in step S6), control returns to step S2 and the detection of smoke concentration according to the arrival of the predetermined timing is repeated. If the count value n has reached a predetermined number of times N in step S6 ("Y" in step S6), an alarm based on the smoke concentration, such as a fire alarm, is issued (step S7), and then control returns to step S1.

[0075] On the other hand, if the detected smoke concentration does not exceed a predetermined threshold ("N" in step S4), it is determined whether or not an alarm has already been triggered (step S8). If an alarm has not been triggered ("N" in step S8), control is returned to step S2 and the detection of smoke concentration according to the arrival of a predetermined timing is repeated. If an alarm has already been triggered ("Y" in step S8), the alarm is stopped (step S9) and control is returned to step S2.

[0076] If an alarm is triggered when a detection concentration exceeding a predetermined threshold is detected only once, steps S1, S5, and S6 are omitted. Also, if an alarm is triggered when a detection concentration exceeding a predetermined threshold is detected N times consecutively, the count value n is cleared between steps S4 and S8.

[0077] On the other hand, as shown in Figure 7B, when the sound-producing means 3 starts operating (step S10), it is determined whether a predetermined smoke concentration detection period (for example, period P3 in the example of Figure 5) has elapsed since the previous smoke concentration detection time (step S11). If the detection period has not elapsed ("N" in step S11), the determination in step S11 is repeated.

[0078] If the detection cycle time has elapsed ("Y" in step S11), the smoke concentration detected by the smoke sensing means 2 is detected (step S3). The detected concentration detected in step S3 may be stored in the storage means 5 (see Figure 1), and if the storage means 5 stores the maximum value of the detected concentration over a predetermined period, the maximum value stored in the storage means 5 may be updated according to the comparison result between the detected concentration detected in step S3 and the stored maximum value.

[0079] Next, it is determined whether a predetermined period (for example, predetermined period P1 in Figure 5) has elapsed since the previous ambient concentration determination time (step S12). If the predetermined period has not elapsed ("N" in step S12), control is returned to step S11 and the detection of smoke concentration according to the elapsed detection cycle is repeated. On the other hand, if the predetermined period has elapsed ("Y" in step S12), it is determined whether the detected concentration of 1 or more during the predetermined period exceeds a predetermined threshold (step S13). In the determination in step S13, the detected concentration during the predetermined period or its maximum value stored in the storage means 5 may be referenced.

[0080] If at least one of the detected concentrations during a predetermined period exceeds a threshold ("Y" in step S13), an alarm based on smoke concentration, such as a fire alarm, is issued (step S7), and control returns to step S11. On the other hand, if none of the detected concentrations during the predetermined period exceed a predetermined threshold ("N" in step S13), it is determined whether an alarm has already been issued (step S8). If an alarm has not been issued ("N" in step S8), control returns to step S11 and the detection of smoke concentration according to the elapsed time of the detection cycle is repeated. If an alarm has already been issued ("Y" in step S8), the alarm is stopped (step S9), and control returns to step S11.

[0081] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than by the description of the embodiments above, and further includes all modifications (exceptions) within the meaning and scope equivalent to the claims.

[0082] For example, the frequency at which smoke concentration is detected during the operation of the sound-emitting means may be changed depending on the frequency and volume of the sound emitted from the sound-emitting means. For example, the higher the frequency and / or the louder the volume, the more frequently the smoke concentration may be detected. Also, if multiple sound-emitting means are provided, such as a buzzer and a speaker, the method for determining the concentration during operation may be selected for each sound-emitting means depending on its position. For example, the closer a sound-emitting means is positioned to the smoke-sensing means, the more frequently the smoke concentration may be detected during its operation. Furthermore, in the smoke detector of this embodiment, the sound-emitting means may emit a sound that includes the resonant frequency of the housing in which the smoke detector is housed. In this embodiment, since the determination of ambient concentration is less affected by sound waves, it is considered that even if the sound from the sound-emitting means resonates, the determination that the ambient concentration exceeds a predetermined threshold is less likely to be delayed. By emitting a sound that resonates with the housing, it may be possible to notify users at a greater distance of the occurrence of an abnormal situation such as a fire.

[0083] In the above embodiment, for the sake of explanation, the processing operation of the smoke detector of the embodiment was described using a flow-driven flowchart that processes sequentially according to the processing flow, but the present invention is not limited thereto. In the present invention, the processing operation of the smoke detector may be performed by event-driven processing, which executes processing on an event-by-event basis. In this case, it may be performed as a completely event-driven system, or a combination of event-driven and flow-driven systems may be used. [Explanation of symbols]

[0084] 100 smoke detector 1. Control means 2 Smoke detection means 22 Smoke detection area 3. Means of pronunciation 4. Means for determining pronunciation 5 Memory means 6 CO detection means 200 Alarm Ca ambient concentration Cd Smoke concentration (detection concentration) within the smoke detection area Cth predetermined threshold Fs pronunciation identification flag Pd smoke detection pulse Pj judgment pulse P1 Predetermined cycle (predetermined period) P3 Concentration detection cycle during sound production Sa alert status Ss pronunciation state

Claims

1. A smoke detection means that outputs a detection signal of a magnitude corresponding to the smoke concentration, A means of producing sound when in operation, A sound-determining means for determining whether or not the sound-producing means is operating, A control means that controls the alarm operation that triggers an alarm if the smoke concentration exceeds a threshold, A smoke detector equipped with, The control means is If the aforementioned sound-producing means is not operating, the concentration is acquired and it is determined whether or not the concentration exceeds a threshold at regular intervals. When the sound-producing means is operating, concentration is acquired at a timing shorter than the fixed period, and at the timing of the fixed period, it is determined whether one or more of the multiple detection concentrations acquired during the previous period exceed the threshold. Smoke detector.

2. The control means determines that the smoke concentration exceeds the threshold when the concentration acquired at the fixed period timing exceeds the threshold a predetermined number of times, if the determination that the concentration has exceeded the threshold exceeds the threshold when the sound-generating means is not operating. The smoke detector according to claim 1.

3. The control means is When the sound-producing means is operating, if it is determined that at one of the multiple detection concentrations acquired during the previous cycle exceeds the threshold at a given time in the fixed cycle, it is determined that the smoke concentration exceeds the threshold. If the sound-producing means is not operating, the smoke concentration is determined to have exceeded the threshold if the concentration acquired at the fixed period timing exceeds the threshold multiple times in a row. A smoke detector according to claim 1 or 2.

4. The system further includes a CO detection means for detecting carbon monoxide concentration, The control means determines whether the carbon monoxide concentration exceeds a threshold and controls the alarm operation. The smoke detector according to any one of claims 1 to 3, wherein the interval for determining whether the carbon monoxide concentration exceeds a threshold is the same whether the sound-emitting means is operating or not.

5. The smoke detector according to any one of claims 1 to 4, further comprising a storage means for storing all or the maximum value of a plurality of concentrations detected during the aforementioned fixed period.

6. The smoke detector according to any one of claims 1 to 5, further comprising a storage means for storing information on whether or not the sound-emitting means is operating.

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