Smoke detector

Abstract

A smoke sensor is provided that can detect smoke more quickly than conventional smoke sensors. The smoke sensor (11) comprises a light-emitting unit (111), a light-receiving unit (113), a light-receiving unit (114), and a control unit (118). The light-receiving unit (113) receives scattered light emitted from the light-emitting unit (111) and scattered by the particle group contained in the air within the area (A). The light-receiving unit (114) receives reflected light emitted from the light-emitting unit (111) and reflected by particles passing through position (B). The control unit (118) counts the pulse waves that appear as the light intensity signal output from the light-receiving unit (114) changes over time, thereby determining the number of particles that have passed through position (B) within a recent predetermined time period. The control unit (118) determines the presence or absence of smoke in the external space based on the number of particles thus measured and the amplitude of the light intensity signal output from the light-receiving unit (113).

Description

[Technical Field]

[0001] This invention relates to a technology for sensing smoke. [Previous Technology]

[0002] There is a smoke detector that detects the occurrence of smoke in the external space by sensing particles contained in the air flowing into the sensing area from the external space.

[0003] A smoke sensor, also known as a photoelectric smoke sensor, emits light from a light-emitting element to a sensing area, and receives the reflected light from particles in the air within the sensing area through a light-receiving element. Then, based on the intensity of the light received and measured by the light-receiving element, the generation of smoke in the external space is detected.

[0004] As one type of photoelectric smoke detector, there is a known method that measures the intensity of scattered light, which is a concentrated reflection of light reflected by a group of particles contained in the air flowing into the sensing area, and determines the presence or absence of smoke from that intensity (hereinafter referred to as the "total scattered light method"). For example, Patent Document 1 discloses the technology of a photoelectric smoke detector with a total scattered light method.

[0005] As another method of photoelectric smoke detector, it is known to measure the intensity of reflected light reflected by a particle passing through a predetermined position within the sensing area, and to measure the diameter (particle size) and number of particles (particle count) from this intensity, and then determine the presence or absence of smoke from the measurement results (hereinafter referred to as the "particle counter method"). Patent document 2 is, for example, a patent document disclosing technology related to the particle counter method of photoelectric smoke detector. [Prior Art Documents] [Patent Documents]

[0006] Patent Document 1: Japanese Patent Application Publication No. 61-53550; Patent Document 2: Japanese Patent Application Publication No. 11-23460 [Summary of the Invention]

[0007] [The problem the invention aims to solve]

[0008] In the case of a photoelectric smoke sensor using total scattered light, smoke will not be detected until the smoke concentration in the sensing area increases and the intensity of light received by the light-receiving element reaches a predetermined threshold. Similarly, in the case of a photoelectric smoke sensor using a particle counter, smoke will not be detected until the number of smoke particles at a predetermined location in the sensing area reaches a predetermined threshold. Therefore, regardless of the type of photoelectric smoke sensor used, a certain amount of time is required from the generation of smoke to its detection.

[0009] In view of the above, the present invention provides a smoke detector that can detect smoke more quickly than conventional smoke detectors. [Means for Solving the Problem]

[0010] To solve the above-mentioned problems, the present invention proposes a smoke detector comprising: a first light intensity measuring means for measuring the concentrated intensity of light reflected by a group of particles contained in air flowing into a predetermined area of ​​a sensing area from external space; a second light intensity measuring means for measuring the intensity of light reflected by each individual particle flowing into the aforementioned external space and passing through a predetermined position within the sensing area; and a determination means for determining the presence or absence of smoke in the aforementioned external space based on the measured values ​​of the first light intensity measuring means and the measured values ​​of the second light intensity measuring means. [Effects of the Invention]

[0011] According to the present invention, since the presence or absence of smoke can be determined by both the intensity of reflected light produced by each smoke particle and the intensity of scattered light produced by the smoke particle group, smoke can be sensed quickly compared with the case where either one is used.

Implementation Method

[0013] [Implementation Form]

[0014] The following describes a smoke detection system 1 according to one embodiment of the present invention. FIG1 is a diagram showing the configuration of the smoke detection system 1. The smoke detection system 1 includes a smoke sensor 11 and an upper system 12.

[0015] The smoke sensor 11 is a device that is disposed in the space of the monitored object where smoke occurs (hereinafter referred to as the "monitoring space"), and takes in the air in the monitoring space, detects the smoke as long as the air after it is taken in contains smoke, and notifies the higher-level system 12 of the occurrence of smoke when smoke is detected.

[0016] In Figure 1, although the number of smoke sensors 11 in the smoke detection system 1 is one, the number of smoke sensors 11 in the smoke detection system 1 varies depending on the number or width of the monitored space.

[0017] The high-level system 12 may also be any of the following: a monitoring terminal device, a smoke alarm panel, a central monitoring system, etc. The high-level system 12 and the smoke sensor 11 are able to communicate with each other via wired, wireless, or a combination of these communication media.

[0018] Since the higher-order system 12 is the same as the higher-order system of the prior art, its description is omitted.

[0019] Figure 2 is a schematic diagram showing the configuration of the smoke detector 11. The smoke detector 11 includes a housing 110, a light-emitting part 111, a lens 112, a light-receiving part 113, a light-receiving part 114, a lens 115, a fan 116, a filter 117, and a control unit 118.

[0020] The housing 110 is a container that forms a space inside. The housing 110 has an air intake port P and an air exhaust port Q. The air intake port P is an opening that functions as an inlet for air to flow from the external space into the internal space, and the air exhaust port Q is an opening that functions as an outlet for air to flow from the internal space into the external space.

[0021] Furthermore, the housing 110 has a wall 1101, a pipe 1102 and a pipe 1103. The wall 1101 is used to form a sensing area S in the internal space as a region for sensing smoke. The pipe 1102 forms an air flow path from the air intake P to the sensing area S. The pipe 1103 forms an air flow path from the sensing area S to the exhaust port Q.

[0022] The light-emitting part 111 (an example of a light-emitting means) has, for example, an LED (an example of a light-emitting element) and emits light towards the air flow path from the intake port P toward the exhaust port Q.

[0023] The lens 112 is responsible for concentrating the light emitted by the light-emitting part 111 and guiding the concentrated light to position B within the sensing area S.

[0024] The light-receiving unit 113 (an example of a first light intensity measuring means) has, for example, a photodiode (an example of a light-receiving element) and receives a portion of the scattered light. It then outputs a light intensity signal, representing the intensity of the received light, to the control unit 118. This scattered light is a concentration of reflected light from the light-emitting unit 111, reflected by a group of particles in the air within region A of the sensing region S, which flows in from the external space. The light-receiving unit 113 is positioned so as not to face the light-emitting unit 111, preventing light emitted from the light-emitting unit 111 from directly incident on the light-receiving unit 113.

[0025] The light-receiving unit 114 (an example of a second light intensity measuring means) has, for example, a photodiode (an example of a light-receiving element), and for each individual particle whose light emitted from the light-emitting unit 111 flows into the external space and passes through position B within the sensing area S, it receives a portion of the reflected light reflected by that particle, and then outputs a light intensity signal representing the intensity of the received light to the control unit 118. The light-receiving unit 114 is positioned so as not to face the light-emitting unit 111, so that the light emitted from the light-emitting unit 111 does not directly incident on the light-receiving unit 114.

[0026] Lens 115 is a lens that concentrates light from position B toward light-receiving part 114. That is, the focal point of lens 115 is position B. With lens 115, light-receiving part 114 can capture reflected light from smoke particles in a region that is so narrow as to be practically a point, centered on position B, that it is impossible for more than two smoke particles to enter at the same time.

[0027] The fan 116 generates the flow of air from the external space through the intake port P into the sensing area S and through the exhaust port Q to the external space by means of rotating blades.

[0028] The filter 117 is disposed in the airflow path from the intake port P to the exhaust port Q to capture dust contained in the air flowing into the sensing area S from the outside space and to prevent dust from entering the sensing area S.

[0029] The control unit 118 is a device for controlling the operation of the smoke sensor 11. The hardware of the control unit 118 is, for example, a computer, and the control unit 118 is implemented by the computer performing processing according to the program used by the control unit 118.

[0030] Figure 3 is a diagram showing the configuration of the computer 10, which is used as the hardware of the control unit 118. The computer 10 includes: a processor 101, which performs various data processing; and a memory 102, which stores various data; an input / output interface 103, which receives and transmits signals between itself and components such as the light-emitting part 111 of the smoke sensor 11; and a communication interface 104, which transmits and receives data between itself and an external device (in this case, a high-level system 12).

[0031] Figure 4 is a diagram showing the functional configuration of the control unit 118. That is, the control unit 118, which has the configuration shown in Figure 4, is implemented by the computer 10 performing processing according to the program used by the control unit 118. The functional configuration of the control unit 118 will be described below.

[0032] The light emission indicator 1181 indicates the light emission of the light emission unit 111. The light intensity signal acquisition means 1182 acquires the light intensity signal output from the light receiving unit 113. The light intensity signal acquisition means 1183 acquires the light intensity signal output from the light receiving unit 114.

[0033] The timing means 1184, for example, continuously measures the current time based on a clock signal generated by the clock provided by the processor 101, and generates a time signal representing the current time.

[0034] The counting means 1185 (which together with the light receiving unit 114 and the light intensity signal acquisition means 1183 constitutes a particle count measuring means) counts the number of particles (hereinafter referred to as "particle count") that have passed position B within the most recent predetermined time period based on the light intensity signal acquired by the light intensity signal acquisition means 1183 from the light receiving unit 114. Furthermore, the counting means 1185 uses a time signal generated by the timing means 1184 to specify the most recent predetermined time that is the object of the particle count.

[0035] The determination means 1186 determines the presence or absence of smoke in the external space based on the intensity of the light intensity signal obtained by the light intensity signal acquisition means 1182 and the number of particles counted by the counting means 1185. The order in which the determination means 1186 determines the presence or absence of smoke will be described later.

[0036] The communication means 1187 is to send smoke occurrence notification data to the higher-level system 12 when the determination means 1186 has determined that smoke exists in the external space.

[0037] Figure 5 shows the time variation of the amplitude of the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving part 113 (Figure 5(a)) and the time variation of the amplitude of the light intensity signal obtained by the light intensity signal acquisition means 1183 from the light receiving part 114 (Figure 5(b)) when the air containing smoke has begun to flow into the sensing area S from the external space.

[0038] The light intensity signal acquired by the light intensity signal acquisition means 1182 from the light receiving unit 113 represents the intensity of the entire reflected light that has reached the light receiving unit 113, among the reflected light reflected by a plurality of particles (particle swarm) within a region A having a certain width. Therefore, the amplitude of the light intensity signal acquired by the light intensity signal acquisition means 1182 from the light receiving unit 113 changes continuously with the change in smoke concentration within the sensing region S.

[0039] On the other hand, the light intensity signal acquired by the light intensity signal acquisition means 1183 from the light receiving unit 114 represents the intensity of the reflected light that has reached the light receiving unit 114 from the reflected light reflected by a particle passing through an extremely narrow region centered at position B, which can be substantially considered a point. Therefore, the light intensity signal acquired by the light intensity signal acquisition means 1183 from the light receiving unit 114 becomes a rising pulse signal at the instant the particle passes through position B. Then, the frequency of the occurrence of such pulse signals, that is, the number of occurrences per predetermined time interval, varies with the change in smoke concentration within the sensing area S.

[0040] The counting means 1185 counts the number of pulse signals shown by the light intensity signal obtained by the light intensity signal acquisition means 1183 from the light receiving unit 114.

[0041] Figure 6 is a flowchart illustrating the processing performed by the determination means 1186. The determination means 1186 performs the processing according to the flow shown in Figure 6 after a very short predetermined time each time. The processing performed by the determination means 1186 will be explained below.

[0042] The determination means 1186 first determines whether the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 has reached the predetermined threshold value Z (step S101).

[0043] In step S101, if it is determined that the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 has not reached the threshold value Z (step S101: no), the determination means 1186 sets a predetermined value X to the threshold value T used in the determination in step S104 (step S102).

[0044] On the other hand, in step S101, if it is determined that the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 has reached the threshold value Z (step S101: Yes), the determination means 1186 sets a predetermined value Y smaller than the value X for the threshold value T used in the determination in step S104 (step S103).

[0045] Following the processing in step S102 or S103, the determination means 1186 determines whether the number of particles being counted by the counting means 1185 has reached the threshold value T that has been set in step S102 or S103 (step S104).

[0046] In step S104, if it is determined that the number of particles being counted by the counting means 1185 has reached the threshold value T (step S104: Yes), the determination means 1186 determines that smoke is occurring in the external space and instructs the communication means 1187 to send smoke occurrence notification data (step S105). The communication means 1187 sends smoke occurrence notification data to the higher-order system 12 according to the instruction of the determination means 1186. Afterwards, the determination means 1186 ends the series of processes shown in FIG6.

[0047] On the other hand, in step S104, if it is determined that the number of particles being counted by the counting means 1185 has not reached the threshold value T (step S104: No), the determination means 1186 determines that smoke has not occurred in the external space and does not instruct the communication means 1187 to send smoke occurrence notification data, and ends the series of processes shown in FIG6.

[0048] As described above, the determination means 1186 determines the presence or absence of smoke in the external space based on a determination condition that the number of particles passing through position B within a recent predetermined time period, as counted by the counting means 1185, has reached a threshold value T. Then, if the light intensity signal received by the light intensity signal acquisition means 1182 from the light receiving unit 113 reaches a predetermined threshold value Z, the determination means 1186 changes the threshold value T to a value Y that is smaller than the normally used value X. As a result, compared to the case where such a change to the threshold value T is not performed, smoke sensing can be performed more quickly.

[0049] [Variations] The above-described embodiments are specific examples of the present invention, and various variations can be made within the scope of the technical concept of the present invention. Examples of such variations are shown below. Furthermore, two or more variations shown below can also be appropriately combined.

[0050] (Variation Example 1) In the above embodiment, the determination means 1186 changes the determination condition for the presence or absence of smoke based on the number of particles counted by the counting means 1185 (that is, the determination condition for the presence or absence of smoke set by the particle count means) based on the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving part 113 (that is, the measured value of the light intensity measuring means).

[0051] Alternatively, the following configuration may be adopted: the determination means 1186 determines the presence or absence of smoke based on the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113, and changes the determination condition (that is, the smoke determination condition set by the light intensity measurement means) based on the number of particles counted by the counting means 1185 (that is, the measurement value of the particle count measurement means).

[0052] Figure 7 is a flowchart illustrating the processing performed by the determination means 1186 in one example of this variation. The determination means 1186 performs the processing according to the flow shown in Figure 7 after a very short predetermined time each time. Hereinafter, the processing performed by the determination means 1186 shown in Figure 7 will be explained.

[0053] The determination means 1186 first determines whether the number of particles being counted by the counting means 1185 has reached a predetermined threshold value Y (step S201).

[0054] In step S201, if it is determined that the number of particles being counted by the counting means 1185 has not reached the threshold value Y (step S201: no), the determination means 1186 sets a predetermined value W for the threshold value T used in the determination in step S204 (step S202).

[0055] On the other hand, in step S201, if it is determined that the number of particles being counted by the counting means 1185 has reached a predetermined threshold value Y (step S201: Yes), the determination means 1186 sets a predetermined value Z smaller than the value W for the threshold value T used in the determination in step S204 (step S203).

[0056] Following the processing in step S202 or S203, the determination means 1186 determines whether the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 has reached the threshold value T that has been set in step S202 or S203 (step S204).

[0057] In step S204, if it is determined that the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 has reached the threshold value T (step S204: Yes), the determination means 1186 determines that smoke is occurring in the external space and instructs the communication means 1187 to send smoke occurrence notification data (step S205). The communication means 1187 sends smoke occurrence notification data to the higher-order system 12 according to the instruction of the determination means 1186. Afterwards, the determination means 1186 ends the series of processes shown in FIG7.

[0058] On the other hand, in step S204, if it is determined that the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 has not reached the threshold value T (step S204: No), the determination means 1186 determines that smoke has not occurred in the external space and does not instruct the communication means 1187 to send smoke occurrence notification data, and ends the series of processes shown in FIG7.

[0059] In this variation, the determination means 1186 determines the presence or absence of smoke in the external space based on a determination condition that the intensity of the scattered light generated by the particle group in region A, as shown by the light intensity signal acquired by the light intensity signal acquisition means 1182, has reached a threshold value T. Then, if the number of particles being counted by the counting means 1185 reaches a predetermined threshold value Y, the determination means 1186 changes the threshold value T to a value Z that is smaller than the normally used value W. As a result, compared to the case where such a change in the threshold value T is not performed, smoke sensing can be performed more quickly.

[0060] Furthermore, based on the smoke sensor 11 of this variation, it is possible to determine the presence or absence of smoke in the external space whose particle size cannot be measured by a particle number measuring means.

[0061] For example, if the particle size of the smoke is small, like that of black smoke, the following situation may occur: even if the smoke particles pass through position B, the amount of reflected light reflected by the particles and reaching the light-receiving section 114 is still small, and no clear pulse signal appears in the light intensity signal output from the light-receiving section 114. In such a case, it is impossible to sense the smoke solely based on the number of particles counted by the counting means 1185.

[0062] However, according to this variation, even when the smoke particle size is small, as long as there are a majority of particles in region A, the amount of reflected light reflected by the particle group and reaching the light-receiving part 113 will still be very large. Therefore, the determination in step S204 will become Yes, and smoke sensing can be performed.

[0063] (Variation Example 2) In the above embodiment, although the condition for determining the presence or absence of smoke set by the particle number measuring means is assumed to be whether the particle number has reached a predetermined threshold value, the condition for determining the presence or absence of smoke set by the particle number measuring means is not limited to this.

[0064] For example, a determination condition for determining that smoke is occurring may be adopted when the number of particles reaches a predetermined threshold and has continued for a predetermined time or longer. In this case, the determination means 1186 may, based on the measurement value of the light intensity measurement means, change the threshold value related to the number of particles contained in the determination condition, or instead change the threshold value related to the duration.

[0065] For example, the determination means 1186 determines that smoke is occurring when the time it takes for the number of particles being counted by the counting means 1185 to reach the threshold value X has continued to be above the threshold value T1, even if the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 has not reached the threshold value Z. On the other hand, the determination means 1186 determines that smoke is occurring when the time it takes for the number of particles being counted by the counting means 1185 to reach the threshold value X has continued to be above the threshold value T2, which is smaller than the threshold value T1, even if the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 has reached the threshold value Z.

[0066] Similarly, in the above variation 1, although the determination condition for the presence or absence of smoke set by the light intensity measuring means is assumed to be whether the light intensity has reached a predetermined threshold value, the determination condition for the presence or absence of smoke set by the light intensity measuring means is not limited to this.

[0067] For example, a determination condition for determining that smoke is occurring may be adopted when the light intensity has reached a predetermined threshold value and has continued for a predetermined time or longer. In this case, the determination means 1186 may, based on the measured value of the particle number measuring means, change the threshold value related to the light intensity contained in the determination condition, or instead change the threshold value related to the duration.

[0068] For example, the determination means 1186 determines that smoke is occurring when the time for the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 to reach the threshold value W has continued to be above the threshold value T1, even if the number of particles being counted by the counting means 1185 has not reached the threshold value Y. On the other hand, the determination means 1186 determines that smoke is occurring when the time for the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 to reach the threshold value W has continued to be above the threshold value T2, which is smaller than the threshold value T1, even if the number of particles being counted by the counting means 1185 has reached the threshold value Y.

[0069] (Variation 3) The shape of the pulse shown by the light intensity signal obtained by the light intensity signal acquisition means 1183 from the light receiving unit 114 varies depending on the particle size of the particle passing through position B. Figure 8 is a graph showing the pattern of the shape of the pulse shown by the light intensity signal obtained by the light intensity signal acquisition means 1183 from the light receiving unit 114 varying with the particle size.

[0070] Figure 8(a) shows the change of light intensity signal over time when a particle with a larger diameter than that in Figure 8(b) passes through position B. Figure 8(b) shows the change of light intensity signal over time when a particle with a smaller diameter than that in Figure 8(a) passes through position B. Furthermore, Figure 8(a) and Figure 8(b) are graphs showing the same airflow velocity (flow rate per unit time) in the sensing area S.

[0071] As shown in Figure 8, the larger the particle size passing through position B, the greater the width of the pulse in the light intensity signal along the time axis. Furthermore, generally speaking, the larger the particle size passing through position B, the greater the amplitude of the pulse in the light intensity signal.

[0072] Therefore, the particle size of the air contained in the sensing area S flowing from the external space, i.e. the particle size of the smoke, can be determined based on the light intensity signal obtained from the light receiving unit 114 by the light intensity signal acquisition means 1183.

[0073] However, when smoke is present in the sensing area S, even if the light intensity of the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 is the same, the smoke concentration will be different when the smoke particle size is different. Generally speaking, when the light intensity of the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 is the same, the smaller the smoke particle size, the higher the smoke concentration.

[0074] Therefore, the smoke sensor 11 may also be configured as follows: based on the amplitude of the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113 and the particle size of the smoke specified by the shape (width or amplitude of the pulse in the time axis direction) of the light intensity signal obtained by the light intensity signal acquisition means 1183 from the light receiving unit 114, it is determined whether smoke is occurring in the external space.

[0075] FIG9 is a diagram showing the functional configuration of the control unit 118 of the smoke detector 11 in this variation example. A portion of the configuration shown in FIG9 is common to the configuration of the control unit 118 in the embodiment shown in FIG4. Other configurations use the same symbols as those used in FIG4. Hereinafter, configurations shown in FIG9 that differ from those shown in FIG4 will be described.

[0076] The particle size calculation means 1188 calculates the particle size of the particle passing through position B. Specifically, the particle size calculation means 1188 calculates the particle size of the particle passing through position B by multiplying the width (or amplitude) of the pulse wave in the time axis direction of the light intensity signal obtained by the light intensity signal acquisition means 1183 from the light receiving unit 114, which varies with time, by the airflow velocity (flow rate per unit time) of the air flowing in the sensing area S. Alternatively, for example, the particle size calculation means 1188 may also specify the particle size of the particle passing through position B according to a correspondence table or a calculation formula. The correspondence table represents the particle size corresponding to the width (or amplitude) in the time axis direction of the pulse wave, and the calculation formula calculates the particle size by treating the width (or amplitude) in the time axis direction of the pulse wave as a variable. The particle size calculation means 1188, together with the light receiving unit 114 and the light intensity signal acquisition means 1183, constitutes a particle size measurement means for measuring the particle size of particles contained in the air flowing into the sensing area S from the outside space.

[0077] Furthermore, when the air velocity flowing in the sensing area S changes, the smoke sensor 11 is configured to have a flow meter that measures the velocity, and the particle size calculation means 1188 can calculate the particle size by multiplying the width of the pulse wave in the time axis direction by the velocity obtained as a result of the flow meter measurement.

[0078] The determination means 1189 determines whether smoke is occurring in the external space based on the particle size calculated by the particle size calculation means 1188 (i.e., the measured value of the particle size measurement means) and the intensity of the light shown by the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving part 113 (i.e., the measured value of the light intensity measurement means).

[0079] For example, the determination means 1189 determines the smoke concentration by referring to a table showing the smoke concentration corresponding to the combination of particle size and light intensity, and specifying the smoke concentration corresponding to the particle size calculated by the particle size calculation means 1188 and the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light receiving unit 113. Alternatively, the determination means 1189 may also calculate the smoke concentration according to a formula that treats particle size and light intensity as variables.

[0080] The determination means 1189 determines that smoke is occurring in the external space when the smoke concentration specified as described above has reached a predetermined threshold. Furthermore, the determination conditions used by the determination means 1189 to determine the presence or absence of smoke are not limited to this. For example, a determination condition that smoke is occurring in the external space can also be adopted when the smoke concentration specified by the determination means 1189 has reached a predetermined threshold for a predetermined period of time or longer.

[0081] Furthermore, the determination method 1189 may not necessarily require a specific smoke concentration. For example, the determination method 1189 may compare the intensity of the light intensity signal obtained by the light intensity signal acquisition method 1182 from the light receiving unit 113 with a threshold value instead of comparing the smoke concentration with the threshold value, thereby determining the presence or absence of smoke; and adjust the light intensity of the light intensity signal obtained from the light receiving unit 113, or the threshold value of the light intensity used to determine the presence or absence of smoke, according to the particle size calculated by the particle size calculation method 1188.

[0082] For example, the determination means 1189 multiplies the light intensity of the light intensity signal obtained from the light receiving unit 113 by a larger multiplier the smaller the particle size after the determination, in order to correct the measurement value of the light receiving unit 113. The determination means 1189 compares the measured value of the light intensity after such correction with the threshold value to determine whether smoke is being generated.

[0083] Alternatively, the determination means 1189 may adjust the threshold value of light intensity used to determine the presence or absence of smoke by multiplying the smaller the specified particle size by a smaller multiplier. The determination means 1189 shall compare the adjusted threshold value of light intensity with the light intensity signal obtained from the light receiving unit 113 to determine whether smoke is occurring.

[0084] As described above, the particle size calculated by the particle size calculation means 1188 is a threshold value used for measurement of the light-receiving part 113 or for comparison with the measurement of the light-receiving part 113. Therefore, the particle size calculated by the particle size calculation means 1188 can be any index value representing the diameter of the particle, and does not necessarily have to be a value representing the diameter of the particle in terms of its length (μm). Thus, for example, the width of the pulse wave in the time axis direction can also be used as a value representing the particle size in its original state. Furthermore, the amplitude of the pulse wave can also be used as a value representing the particle size in its original state.

[0085] Communication means 1190, when determination means 1189 has detected smoke, sends particle size notification data calculated by particle size calculation means 1188, together with smoke detection notification data, to higher-level system 12. The particle size shown in the particle size notification data is information indicating the type of smoke (black smoke, white smoke, etc.). For example, managers who receive smoke occurrence notification through higher-level system 12 can use the simultaneously notified particle size for specific fire source or appropriate fire extinguishing methods.

[0086] (Variation 4) In the above embodiment, the scattered light concentrated from the reflected light reflected by the particle group in region A and the reflected light reflected by the particles passing through position B, received by the light-receiving part 113, are emitted from the same light-emitting part 111. Alternatively, the light source for the light received by the light-receiving part 113 and the light source for the light received by the light-receiving part 114 may be configured differently.

[0087] FIG10 is a schematic diagram showing the configuration of one example of such a smoke sensor 11. The smoke sensor 11 shown in FIG10 includes a light-emitting part 111 (1) and a light-emitting part 111 (2).

[0088] The light-emitting part 111(1) emits light toward region A. The light-receiving part 113 receives a portion of the scattered light that is a concentrated reflection of the light emitted from the light-emitting part 111(1) and reflected by the particle group in region A.

[0089] The light-emitting part 111(2) irradiates light toward position B in the area outside region A. The light-receiving part 114 receives a portion of the reflected light emitted from the light-emitting part 111(2) and reflected by the particles passing through position B.

[0090] Furthermore, compared with the smoke sensor 11 of the variation example, the smoke sensor 11 of the above embodiment has fewer necessary light-emitting parts, so it is better in terms of miniaturization and cost reduction.

[0091] (Variation 5) In the above embodiment, the sensing area S including the region A that generates scattered light received by the light-receiving part 113 and the sensing area S including the position B that generates reflected light received by the light-receiving part 114 are the same region. Alternatively, the region A and the position B may be contained in different sensing areas.

[0092] Figure 11 is a schematic diagram showing the configuration of one example of such a smoke detector 11. The housing 110 of the smoke detector 11 shown in Figure 11 has sensing areas S11 and S12, which belong to different sensing regions, formed internally. Here, different sensing regions mean regions that are distinguished in such a way that light emitted from one region does not actually reach the other region, and do not necessarily need to be completely separated regions. Sensing area S11 includes region A, and sensing area S12 includes location B.

[0093] The smoke detector 11 shown in FIG11 has a light-emitting part 111 disposed at the boundary between the sensing area S11 and the sensing area S12, and illuminates light to both the sensing area S11 and the sensing area S12. Furthermore, the light-emitting part 111 may also be composed of two different light-emitting parts disposed in the sensing area S11 and the sensing area S12 respectively.

[0094] Furthermore, compared with the smoke sensor 11 of the variation example, the smoke sensor 11 of the above embodiment is better in terms of miniaturization because the sensing area including region A and the sensing area including location B are the same region.

[0095] (Variation 6) In the above embodiment, the light-receiving part 113 and the light-receiving part 114 are each equipped with different light-receiving elements (e.g., photodiodes) and receive light individually. Alternatively, the light-receiving part 113 and the light-receiving part 114 may also be configured to measure the intensity of light by using the same light-receiving element.

[0096] Figure 12 is a schematic diagram showing the configuration of the smoke sensor 11 in this variation example. Figure 13 is a diagram showing the functional configuration of the control unit 118 in this variation example.

[0097] In this variation, the light-receiving part 114 also performs the function of the light-receiving part 113. Furthermore, in this variation, the smoke sensor 11, in addition to having a light-emitting part 111, also has a light-emitting part 119, which is different from the light-emitting part 111. The light-emitting part 119 illuminates a wider area A, closer to the light-receiving part 114 than the position B.

[0098] Then, in this variation, the light-emitting indicator 1191 provides an indication of light emission to the light-emitting parts 111 and 119, indicating that they emit light at different times. That is, the light-emitting parts 111 and 119 emit light with a time difference and do not emit light simultaneously. Then, the light-receiving part 114 when the light-emitting part 119 is emitting light performs the function of the light-receiving part 113 (an example of the first light-receiving means) in the above embodiment, and the light-receiving part 114 when the light-emitting part 111 is emitting light performs the function of the light-receiving part 114 (an example of the second light-receiving means) in the above embodiment.

[0099] The counting means 1185 and the determination means 1186 determine the light intensity signal received from the light receiving part 114 through the light intensity signal acquisition means 1183, and indicate the intensity of light when either the light emitting part 111 or the light emitting part 119 emits light.

[0100] The counting means 1185 uses the light intensity signal output by the light receiving part 114 when the light emitting part 111 is emitting light to count the number of particles passing through position B. The determination means 1186 determines the presence or absence of smoke based on the light intensity signal shown by the light receiving part 114 output by the light emitting part 119 when it is emitting light, and the number of particles counted by the counting means 1185.

[0101] In this variation, the light-emitting part 111 and the light-emitting part 119 may also be constructed by emitting light using the same light-emitting element (LED, etc.). For example, the smoke detector 11 may replace the light-emitting part 119 shown in FIG12 with a mirror that passes between the light-emitting part 111 and the lens 112. This mirror may also be constructed in such a way that it guides the light emitted from the light-emitting part 111 to region A when it is located between the light-emitting part 111 and the lens 112. In this case, the light-emitting part 111, with the mirror located between the light-emitting part 111 and the lens 112, performs the function of the light-emitting part 119 in FIG12.

[0102] (Other) In the above embodiment, although it is assumed that the hardware of the control unit 118 is a computer, the control unit 118 may also be configured as a special device with integrated circuits such as ASIC (Application Specific Integrated Circuit) and FPGA (Field Programmable Gate Array). [Simplified Explanation of the Diagram]

[0012] [Figure 1] is a diagram showing the configuration of a smoke detection system according to an embodiment. [Figure 2] is a diagram schematically showing the configuration of a smoke detector according to an embodiment. [Figure 3] is a diagram showing the configuration of a computer used as the hardware of a control unit according to an embodiment. [Figure 4] is a diagram showing the functional configuration of a control unit according to an embodiment. [Figure 5] is a graph showing the time-varying amplitude of the light intensity signal output from the two light-receiving units of the smoke detector according to an embodiment. [Figure 6] is a diagram illustrating the processing flow performed by the determination means according to an embodiment. [Figure 7] is a diagram illustrating the processing flow performed by the determination means according to a modified example. [Figure 8] is a graph showing the pattern of the pulse shape of the light intensity signal output from the light-receiving unit of a modified example changing according to the particle size. [Figure 9] is a diagram showing the functional configuration of a control unit according to a modified example. [Figure 10] is a schematic diagram showing the configuration of a modified smoke detector. [Figure 11] is a schematic diagram showing the configuration of a modified smoke detector. [Figure 12] is a schematic diagram showing the configuration of a modified smoke detector. [Figure 13] is a schematic diagram showing the functional configuration of a modified control unit.

Claims

1. A smoke detector comprising: a first light intensity measuring means for measuring the concentrated intensity of light reflected by a group of particles contained in air flowing into a predetermined area of ​​a sensing area from an external space; a second light intensity measuring means for measuring the intensity of light reflected by each individual particle flowing into the aforementioned external space and passing through a predetermined position within the sensing area; and a determination means for determining the presence or absence of smoke in the aforementioned external space based on the measured values ​​of the first light intensity measuring means and the measured values ​​of the second light intensity measuring means.

2. The smoke detector as described in claim 1, wherein, The aforementioned determination method is based on the measurement value of the aforementioned second light intensity determination method to change the determination conditions for the presence or absence of smoke set by the measurement value of the aforementioned first light intensity measurement method.

3. The smoke detector as described in claim 1, wherein, The aforementioned determination method is based on the measurement value of the aforementioned first light intensity determination method, and modifies the determination conditions for the presence or absence of smoke set by the measurement value of the aforementioned second light intensity determination method.

4. The smoke detector as described in claim 1, wherein, The aforementioned determination method is used to determine the presence or absence of smoke particles in the aforementioned external space whose particle size cannot be measured by the aforementioned second light intensity measurement method.

5. The smoke detector as described in claim 1, wherein, It possesses: a particle count measurement method, which measures the number of particles passing through the predetermined position based on the measurement value of the aforementioned second light intensity measurement method; and a determination method, which determines the presence or absence of smoke in the aforementioned external space based on the number of particles measured by the aforementioned particle count measurement method.

6. The smoke detector as described in claim 1, wherein, It possesses: a particle size measurement means, which measures the particle size of a particle passing through the predetermined position based on the measurement value of the aforementioned second light intensity measurement means; and a determination means, which determines the presence or absence of smoke in the aforementioned external space based on the particle size measured by the aforementioned particle size measurement means.

7. The smoke detector as described in claim 6, wherein, The aforementioned determination method is based on the measured value of the aforementioned first light intensity measurement method and the particle size measured by the aforementioned particle size measurement method to determine the concentration of smoke in the aforementioned external space, and to determine the presence or absence of smoke in the aforementioned external space based on the determined concentration.

8. The smoke detector as described in claim 1, wherein, It has a means of emitting light; the aforementioned first light intensity measuring means and the aforementioned second light intensity measuring means measure the intensity of the reflected light after the light is emitted from the same aforementioned light-emitting means.

9. The smoke detector as described in claim 1, wherein, The aforementioned first light intensity measurement method and the aforementioned second light intensity measurement method both measure the light intensity using the same light-receiving element; the aforementioned first light intensity measurement method measures the light intensity using the aforementioned light-receiving element when emitting light to the aforementioned predetermined area but not to the aforementioned predetermined position; the aforementioned second light intensity measurement method measures the light intensity using the aforementioned light-receiving element when emitting light to the aforementioned predetermined position but not to the aforementioned predetermined area.

10. The smoke detector as described in claim 1, wherein, The sensing area containing the aforementioned predetermined location is the same area as the sensing area containing the aforementioned predetermined area.

Images