JP6029055B2 - smoke detector - Google Patents

Description

  The present invention relates to a smoke detector.

  Conventionally, there has been a photoelectric smoke detector in which a light emitting element and two light receiving elements are arranged in a dark box (see, for example, Patent Document 1).

  In the photoelectric smoke detector, when smoke flows into the dark box, the light emitted from the light emitting element is scattered by the smoke, and the scattered light is incident on the light receiving element. The presence or absence of smoke is detected by comparing the height. However, if insects or dust enter the darkroom, light scattered by the insects or dust may enter the light receiving element and cause false alarms. When two light receiving elements receive scattered light due to smoke in different light receiving areas, and the scattered light is received only in one of the light receiving areas, it is determined as an erroneous report due to insects or dust.

Japanese Utility Model Publication No. 2-6394

  In the smoke detector of Patent Document 1 described above, a separator is provided in the dark box in order to make the light receiving areas of the two light receiving elements independent. The interior of the dark box is optically designed so that the light emitted from the light emitting element is reflected and does not enter the light receiving element. However, when the separator is arranged so as to partition the inside of the dark box, the optical design must be performed. There is a problem that it is difficult. In addition, the provision of the separator plate increases the size of the dark box, thereby increasing the size of the entire smoke detector.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a small smoke detector with reduced false detection due to insects and dust.

The smoke detector of the present application includes a smoke detection chamber, a plurality of light emitting units, a light receiving unit, and a determination unit. The smoke sensing chamber suppresses the entry of light from the outside and allows the smoke to enter and exit. The plurality of light emitting units respectively emit light into the smoke sensing chamber. The light receiving unit has a light receiving range set in the smoke sensing chamber. The determination unit determines whether smoke has entered the smoke sensing chamber based on the output of the light receiving unit. The light receiving unit is configured so that direct light from the plurality of light emitting units does not enter, and a plurality of regions in which an irradiation range of the plurality of light emitting units respectively overlaps a light receiving range of the light receiving unit. becomes the detection region, the at least one integral of said plurality of light emitting portion and the light receiving portion, the light limiting member for limiting the range of light as the plurality of detection areas do not overlap are provided.

  In this smoke detector, it is also preferable that the crossing angle formed by the optical axis of each of the light emitting units and the optical axis of the light receiving unit is set to be different from each other.

  In this smoke detector, it is also preferable that the plurality of light emitting units are arranged on the same side with respect to the optical axis of the light receiving unit on a plane including the optical axes of the plurality of light emitting units and the light receiving unit.

  In the smoke detector, it is also preferable that the plurality of light emitting units are arranged on both sides with respect to the optical axis of the light receiving unit on a plane including the optical axes of the plurality of light emitting units and the light receiving unit.

  In the smoke detector, the determination unit controls light emission of the plurality of light emitting units so that the plurality of light emitting units do not emit light simultaneously. And it is also preferable that the said determination part determines the state in the said smoke sensing chamber based on the output of the said light-receiving part in the state which light-emitted each of the said several light emission part separately.

  In this smoke detector, the determination unit emits the light emitting unit corresponding to the detection region at a time interval shorter than a movement time necessary for movement of foreign substances other than smoke between the plurality of detection regions. Let The determination unit outputs an output of the light receiving unit in a state where one of the light emitting units emits light exceeds a threshold value and another light emitting unit emits light. When the threshold is smaller than the threshold value, it is also preferable to determine that a foreign substance other than smoke has entered the smoke sensing chamber.

  In the smoke detector, the determination unit causes the corresponding light emitting unit to emit light at a time interval shorter than a moving time necessary for moving foreign substances other than smoke between the plurality of detection regions. The determination unit may determine that smoke has entered the smoke sensing chamber when all the outputs of the light receiving unit in the state where each of the plurality of light emitting units individually emit light exceeds a threshold value. preferable.

  In the smoke detector, it is also preferable that the determination unit causes the plurality of light emitting units to emit light intermittently and performs a determination operation based on the output of the light receiving unit.

  In this smoke detector, the determination unit causes any one of the light emitting units to emit light intermittently in a non-detection state. And when the output of the said light-receiving part exceeds a threshold value in the state in which any one said light-emitting part light-emitted, the said determination part will be required movement for foreign substances other than smoke to move among the said several detection area | regions It is also preferable that each of the other light emitting units emit light individually at a time interval shorter than the time.

  In this smoke detector, the crossing angle formed by the optical axis of each of the light emitting units and the optical axis of the light receiving unit is set to be different from each other, and the determination unit determines the level of the output of the light receiving unit and the threshold value. By comparing, it is determined whether or not smoke has entered the smoke sensing chamber. And the ratio of the output of the light receiving part in the state where the light emitting part having a relatively small crossing angle emits the output of the light receiving part in the state in which the light emitting part having a relatively large crossing angle emits light However, when it becomes larger than a predetermined reference value, it is also preferable that the determination unit determines that the smoke that has entered the smoke sensing chamber is black smoke and lowers the threshold value.

  In this smoke detector, the determination unit sets at least one of the light emission time and the light emission amount of the light emitting unit having a relatively small crossing angle to be larger than that of the light emitting unit having a relatively large crossing angle. It is also preferable to do.

  In this smoke detector, the determination unit causes only the light emitting unit having a relatively large intersection angle to emit light in a non-detected state. And when the output of the said light-receiving part exceeds a threshold value in the state which the said light-emitting part light-emitted, the said determination part is shorter than the movement time required in order to move foreign materials other than smoke between the said several detection area | regions It is also preferable that the other light emitting units emit light at time intervals.

The smoke detector according to one aspect of the present application includes a smoke detection chamber that suppresses the entrance of light from outside and allows smoke to enter and exit, a light emitting unit that emits light into the smoke detection chamber, and a smoke detection chamber, respectively. A plurality of light receiving units in which a light receiving range is set; and a determination unit that determines whether smoke has entered the smoke sensing chamber based on outputs of the plurality of light receiving units. The plurality of light receiving parts are configured so that direct light from the light emitting part is not incident thereon. A plurality of areas in which the irradiation range of the light emitting unit overlaps the light receiving ranges of the plurality of light receiving units respectively become a plurality of detection areas. A light limiting member is provided integrally with at least one of the light emitting unit and the plurality of light receiving units to limit the light range so that the plurality of detection regions do not overlap. The crossing angles formed by the optical axes of the light receiving units and the optical axes of the light emitting units are set to different angles. The determination unit simultaneously captures the outputs of the plurality of light receiving units, compares the output of the plurality of light receiving units with a threshold value, and if all the outputs of the plurality of light receiving units exceed the threshold value, the smoke Judging that smoke has entered the sensing chamber. When the ratio of the output of the light receiving unit having a relatively small cross angle to the output of the light receiving unit having a relatively large cross angle is greater than a predetermined reference value, the determination unit is placed in the smoke sensing chamber. The entered smoke is identified as black smoke, and the threshold is lowered.

  In this smoke detector, the plurality of light receiving units are arranged on the same side with respect to the optical axis of the light emitting unit on a plane including the optical axis of the light emitting unit and the optical axes of the plurality of light receiving units. Is also preferable.

  In the smoke detector, a plurality of the light receiving units may be arranged on both sides with respect to the optical axis of the light emitting unit on a plane including the optical axis of the light emitting unit and the optical axes of the plurality of light receiving units. preferable.

  In this smoke detector, the determination unit simultaneously captures the outputs of the plurality of light receiving units, the outputs of some of the light receiving units exceed a threshold value, and the outputs of the other light receiving units are smaller than the threshold value. In this case, it is also preferable to determine that a foreign substance other than smoke has entered the smoke sensing chamber.

  In this smoke detector, the determination unit operates only one of the light receiving units among the plurality of light receiving units in a state where it has not detected that a foreign object has entered the smoke detection chamber, and takes in an output. When the captured output exceeds the threshold, it is also preferable to operate the other light receiving unit to capture the output.

  ADVANTAGE OF THE INVENTION According to this invention, the small smoke detector which reduced the false detection by an insect and dust can be provided.

It is a top view which shows the principal part of the smoke detector of Embodiment 1. (A) is explanatory drawing which showed arrangement | positioning of the light-receiving part and light emission part same as the above, (b) is a figure which shows power distribution of the scattered light by smoke with comparatively large particle diameter, (c) is particle diameter It is a figure which shows the power distribution of the scattered light by comparatively small smoke. (A) is explanatory drawing which showed typically arrangement | positioning of the light emission part and light reception part same as the above, (b) is explanatory drawing which showed typically arrangement | positioning of the light emission part and light reception part of Embodiment 2. FIG. (A) (b) is explanatory drawing which showed typically arrangement | positioning of the light emission part and light reception part same as the above. It is explanatory drawing which showed typically arrangement | positioning of the light emission part of the smoke detector of Embodiment 4, and a light-receiving part. (A) (b) is a time chart explaining operation | movement same as the above. It is a time chart explaining another operation | movement same as the above. It is a time chart explaining another operation | movement same as the above. It is explanatory drawing which showed typically arrangement | positioning of the light emission part and light reception part same as the above. It is a graph which shows the relationship between smoke density same as the above, and scattered light intensity, (a) is a graph in the case of black smoke, (b) is a graph in the case of white smoke. It is a time chart explaining another operation | movement same as the above. It is a time chart explaining another operation | movement same as the above. It is a flowchart explaining operation | movement same as the above. FIG. 10 is an explanatory diagram schematically showing the arrangement of light emitting units and light receiving units in a fifth embodiment. It is a time chart explaining operation | movement same as the above.

  An embodiment of the present application will be described with reference to the drawings.

(Embodiment 1)
Embodiment 1 of this application is demonstrated with reference to drawings.

  FIG. 1 is a plan view schematically showing a main part of the smoke detector 1, which includes a smoke detection chamber 2, light emitting units 3 a and 3 b, a light receiving unit 4, a determination unit 5, As a main component.

  The smoke detection chamber 2 includes an optical base 6 having a circular cross section. The optical base 6 includes a substantially disc-shaped bottom plate 7 and a plurality of labyrinth walls 8. The plurality of labyrinth walls 8 protrude from the outer peripheral portion of the bottom plate 7 in a direction substantially orthogonal to the bottom plate 7 and surround the inner space. A gap 9 between adjacent labyrinth walls 8 is an entrance through which smoke flows from the outside into the smoke sensing chamber 2. In addition, a bent portion is provided at an intermediate portion of the labyrinth wall 8, and the light entering through the gap 9 from the outside is reflected outward by the labyrinth wall 8, thereby allowing light from the outside to enter. Suppressed. FIG. 1 is a schematic diagram, and the shape, number, and arrangement of the labyrinth wall 8 can be appropriately changed so as not to prevent the inflow of smoke while suppressing the entry of light from the outside. Further, in the smoke sensing chamber 2, a light-shielding wall that shields direct light between the light emitting units 3a and 3b and the light receiving unit 4 so that irradiation light from the light emitting units 3a and 3b does not directly enter the light receiving unit 4. 10 is provided.

  In the smoke sensing chamber 2, two light emitting units 3a and 3b and one light receiving unit 4 are arranged. The optical axis L3 of the light receiving unit 4 and the optical axes L1 and L2 of the light emitting units 3a and 3b are on the same plane, and the optical axis of the light emitting units 3a and 3b with respect to the optical axis L3 of the single light receiving unit 4 provided. The light emitting units 3a and 3b and the light receiving unit 4 are arranged so that L1 and L2 intersect each other.

  When smoke flows into the detection region A1 where the optical axis L1 of the light emitting unit 3a and the optical axis L3 of the light receiving unit 4 intersect, that is, the detection region A1 where the irradiation range S1 of the irradiation light and the light reception range S3 of the received light overlap. The light emitted from the light emitting unit 3 a is scattered by the smoke inside, and a part of the scattered light enters the light receiving unit 4. Further, when smoke flows into the detection region A2 where the optical axis L2 of the light emitting unit 3b and the optical axis L3 of the light receiving unit 4 intersect, that is, the detection region A2 where the irradiation range S2 of the irradiated light and the light receiving range S3 of the received light overlap. The light emitted from the light emitting unit 3 b is scattered by the smoke in A 2, and a part of the scattered light enters the light receiving unit 4.

  Here, a light limiting member (so-called aperture) 11 for limiting the irradiation ranges S1 and S2 of the irradiation light is provided integrally with the light emitting units 3a and 3b so that the two detection regions A1 and A2 do not overlap. The emitted light of each light emission part 3a, 3b is irradiated to corresponding detection area | region A1, A2 through the opening 11a of the light limiting member 11. FIG. Similarly, a light limiting member (so-called aperture) 12 for limiting the light receiving range S3 of the received light is provided integrally with the light receiving unit 4 so that the two detection areas A1 and A2 do not overlap, and the light from the detection areas A1 and A2 Is incident on the light receiving portion 4 through the opening 12 a of the light limiting member 12. In the present embodiment, the light limiting members 11 and 12 are provided on both the light emitting side and the light receiving side, but it is not always necessary to provide the light limiting members 11 and 12 on both the light emitting side and the light receiving side. If the light limiting member is provided on only one of the light emitting side and the light receiving side and the range of light (either irradiated light or received light) can be limited so that a plurality of detection regions do not overlap, light emission The light limiting member may be provided on only one of the side and the light receiving side.

  The determination unit 5 has a function of controlling the light emission of the light emitting units 3 a and 3 b and a function of determining the presence or absence of smoke from the output of the light receiving unit 4. In the determination unit 5, the light emitting units 3a and 3b are alternately turned on at predetermined time intervals, and whether or not the amount of light received by the light receiving unit 4 exceeds a predetermined threshold value with the light emitting unit 3a or the light emitting unit 3b turned on. Determine. If the amount of light received by the light receiving unit 4 exceeds the threshold both when the light emitting unit 3a is lit and when the light emitting unit 3b is lit, the determination unit 5 determines that smoke is flowing into the smoke sensing chamber 2. Then, the smoke detection signal is issued to the outside. If the light receiving amount of the light receiving unit 4 exceeds the threshold only when one of the light emitting units 3a and 3b is turned on, but the light receiving amount of the light receiving unit 4 does not exceed the threshold when the other is turned on, the determining unit 5 It is determined that no smoke is flowing in. If the light receiving amount of the light receiving unit 4 does not exceed the threshold value both when the light emitting unit 3a is lit and when the light emitting unit 3b is lit, the determining unit 5 determines that no smoke is flowing into the smoke sensing chamber 2. To do.

  By the way, when an insect or dust enters the smoke sensing chamber 2, scattered light is generated by the insect or dust that has entered the detection area A1 or the detection area A2, and the light receiving unit 4 may receive the scattered light. There is. However, since it is unlikely that insects and dust will enter both detection areas A1 and A2 at the same time, the determination unit 5 determines that scattered light is detected only in one of the detection areas A1 and A2. Not judged as smoke. Note that the determination unit 5 causes the light emitting units 3a and 3b to emit light at a time interval shorter than the movement time necessary for movement of foreign substances (insects and dust) other than smoke between the two detection areas A1 and A2. Yes. Therefore, when a foreign substance (insect or dust) other than smoke enters the smoke sensing chamber 2, the output of the light receiving unit 4 exceeds the threshold value both when the light emitting unit 3a emits light and when the light emitting unit 3b emits light. There is no.

  On the other hand, when smoke generated by a fire or the like enters the smoke detection chamber 2, the flow of smoke is controlled by the labyrinth wall 8 or the like so that the smoke flows into both the detection regions A1 and A2. , A2 determines that smoke is present only when scattered light is detected in both.

  Therefore, in the smoke detector 1 of the present embodiment, erroneous detection due to foreign matters other than smoke (such as insects and dust) is unlikely to occur, and smoke can be reliably detected. In addition, since the light limiting member 11 that limits the range of the irradiated light is provided integrally with the light emitting units 3a and 3b, and the light limiting member 12 that limits the range of the received light is provided integrally with the light receiving unit 4, light emission Compared with the case where the light limiting member is provided separately from the parts 3a and 3b and the light receiving part 4, the smoke detector 1 can be reduced in size. Further, if the light limiting member is provided separately from the light emitting units 3a and 3b and the light receiving unit 4, the light limiting member itself may cause stray light. Therefore, the light limiting member is used as the light emitting units 3a and 3b. In addition, the optical design is easier than in the case where the light receiving unit 4 is provided separately from the light receiving unit 4.

  In addition, a plurality of light emitting units 3a and 3b are provided for one light receiving unit 4, and the plurality of light emitting units 3a and 3b irradiate the corresponding detection areas A1 and A2, respectively. The number of the light receiving parts 4 can be reduced as compared with the case where each of the light receiving parts and the light emitting parts is detected.

  Further, in each of the detection areas A1 and A2, an angle θ1 formed by the optical axis L1 of the light emitting unit 3a and the optical axis L3 of the light receiving unit 4, and an angle formed by the optical axis L2 of the light emitting unit 3b and the optical axis L3 of the light receiving unit 4 The light emitting units 3a and 3b and the light receiving unit 4 are arranged so that θ2 is different. Here, as shown in FIGS. 1 and 2A, the angle θ1 formed by the optical axis L1 of the light emitting unit 3a and the optical axis L3 of the light receiving unit 4 in the detection region A1 becomes an obtuse angle, and the light emitting unit 3b in the detection region A2. The angle θ2 formed by the optical axis L2 of the light and the optical axis L3 of the light receiving unit 4 is an acute angle (θ1> θ2).

  FIGS. 2B and 2C show the power distribution of scattered light when light strikes the smoke particles 20, and FIG. 2B shows the power distribution when smoke having a relatively large particle diameter. FIG. (C) shows the power distribution in the case of smoke having a relatively small particle size. From this figure, it can be seen that when the particle size is large, the forward scattering component is large, and when the particle size is small, the forward scattering component is small, approaching the power distribution that is scattered almost uniformly in all directions. .

  Therefore, when the angle between incident light and scattered light is relatively large, that is, when the angle between the optical axis of the light emitting portion and the optical axis of the light receiving portion is relatively large, the output from the light receiving portion depends on the size of the particle diameter. The magnitude of the signal will change greatly. Therefore, the output signal in the case of smoke with a small particle size is greatly different from the output signal in the case of smoke with a large particle size, but a larger output signal is obtained for smoke with a large particle size. The presence of smoke can be detected without being affected by noise.

  On the other hand, when the angle formed between the incident light and the scattered light is relatively small, that is, when the angle formed between the optical axis of the light emitting unit and the optical axis of the light receiving unit is relatively small, the angle formed between the incident light and the scattered light is large. Although the magnitude of the output signal is generally smaller than the case, the magnitude of the output signal does not change much depending on the size of the particle diameter, so that there is an advantage that even smoke having a small particle diameter can be easily detected.

  In the present embodiment, the angle between the optical axis of the light emitting unit and the optical axis of the light receiving unit is different in each of the two detection areas A1 and A2, and the optical axis of the light emitting unit and the optical axis of the light receiving unit are formed. In the detection area A1 having a relatively large angle, the influence of noise is reduced by increasing the signal level, and smoke having a large particle diameter is easily detected. In addition, in the detection region A2 in which the angle formed by the optical axis of the light emitting unit and the optical axis of the light receiving unit is relatively small, the difference in signal level caused by the size of the particle size is small, so smoke with a relatively small particle size is generated. It becomes easy to detect.

  Further, in the present embodiment, as shown in FIG. 3A, a plurality of light emitting units 3a and 3b and a plane including the optical axes L1, L2 and L3 of the light receiving unit 4 (a plane parallel to the bottom plate 7) are provided. The light emitting units 3a and 3b are arranged on the same side with respect to the optical axis L3 of the light receiving unit 4 provided with only one.

  As a result, stray light is generated because only one light shielding wall 10 (light shielding member) that shields radiation emitted from the light emitting section 3a and light emitted from the light emitting section 3b from directly entering the light receiving section 4 is required. Therefore, it is not necessary to provide a plurality of light shielding walls 10 and the optical design can be easily performed.

(Embodiment 2)
Embodiment 2 of this application is demonstrated based on drawing.

  In the first embodiment, a plurality of light emitting units 3a and 3b are provided for one light receiving unit 4 in order to provide a plurality of detection regions. In the present embodiment, one light emitting unit is provided as shown in FIG. A plurality of detection areas A1 and A2 are set by providing a plurality of light-receiving portions 4a and 4b for 3.

  In this case, smoke flows into the smoke sensing chamber 2, and the vicinity where the optical axis L1 of the light emitting unit 3 and the optical axis L3 of the light receiving unit 4a intersect, that is, the irradiation range S1 of the irradiated light and the light receiving range S3 of the received light. When the smoke flows into the detection area A1 where the two overlap, the irradiation light is scattered by the smoke in the detection area A1, and a part of the scattered light enters the light receiving unit 4a. Further, when smoke flows into the detection area A2 where the optical axis L1 of the light emitting section 3 and the optical axis L4 of the light receiving section 4b intersect, that is, the detection area A2 where the irradiation range S1 of the irradiated light and the light receiving range S4 of the received light overlap. Irradiation light is scattered by the smoke in A2, and a part of the scattered light enters the light receiving portion 4b.

  Here, as in the first embodiment, a light limiting member (not shown) for limiting the irradiation range in which the light emitting unit 3 emits light, and the light receiving units 4a and 4b so that the two detection areas A1 and A2 do not overlap. Are provided with light limiting members (not shown) for limiting the light receiving range for receiving light. That is, a light limiting member for limiting the irradiation range S1 of the irradiation light is provided integrally with the light emitting unit 3, and the radiated light of the light emitting unit 3 is irradiated to the detection areas A1 and A2 through the opening of the light limiting member. Further, a light restricting member (not shown) for restricting the light receiving ranges S3 and S4 of the received light is provided integrally with the light receiving parts 4a and 4b, respectively, and the light restricting members provided integrally with the light receiving parts 4a and 4b, respectively. Light from the corresponding detection areas A1 and A2 is incident through the openings.

  In the smoke detector 1, the determination unit 5 controls the light emission of the light emitting unit 3, operates the light receiving units 4a and 4b, captures the output thereof, and determines the presence or absence of smoke based on the outputs of the light receiving units 4a and 4b. Sense. The determination unit 5 determines that smoke is present in the smoke detection chamber 2 when both the output signals of the light receiving units 4a and 4b when the light emitting unit 3 is turned on exceed a predetermined threshold, and sends the smoke detection signal to the outside. Output to. Further, the determination unit 5 is configured such that when both the output signals of the light receiving units 4a and 4b do not exceed the threshold when the light emitting unit 3 is turned on, only one of the light receiving units 4a and 4b exceeds the threshold. If so, determine that no smoke is present. Thereby, it is possible to reduce the possibility of erroneously detecting insects and dust that have entered the smoke detection chamber 2 as smoke. In addition, since the light limiting member for limiting the light range is provided integrally with the light emitting unit 3 and the light receiving units 4a and 4b, the light limiting member is provided separately from the light emitting unit 3 and the light receiving units 4a and 4b. In comparison with the above, the smoke detector 1 can be miniaturized and the optical design is facilitated.

  Since a plurality of light receiving units 4a and 4b are provided for one light emitting unit 3 in order to provide a plurality of detection regions A1 and A2 as described above, each of the detection regions A1 and A2 is provided with a light receiving unit and a light emitting unit. Compared to the case of detecting with a set of parts, the number of light emitting parts 3 can be reduced, and the cost can be reduced. Further, when a plurality of light emitting units are provided for one light receiving unit, it is necessary to detect the presence or absence of smoke in each of the detection areas A1 and A2 by turning on the light emitting units one by one. Since a plurality of light receiving portions 4a and 4b are provided for one light emitting portion 3, it is possible to simultaneously detect the presence or absence of smoke in the detection areas A1 and A2.

(Embodiment 3)
In the first and second embodiments described above, a plurality of light emitting units or light receiving units provided on the plane including the optical axes of the light emitting unit and the light receiving unit are provided with respect to the optical axis of only one light receiving unit or light emitting unit. As shown in FIG. 4, a plurality of light emitting units or light receiving units are arranged on both sides with respect to the optical axis of only one light receiving unit or light emitting unit. May be.

  In the arrangement example of FIG. 4A, two light emitting units 3a and 3b are provided for one light receiving unit 4, and on a plane including the light axes 3a and 3b and the optical axes L1, L2 and L3 of the light receiving unit 4. Thus, a plurality of light emitting units 3a and 3b are arranged on both sides with respect to the optical axis L3 of the single light receiving unit 4 provided. That is, the two light emitting units 3a and 3b are arranged diagonally across the optical axis L3 so that the optical axes L1 and L2 are substantially parallel to each other. When smoke flows into the detection region A1 where the optical axis L1 of the light emitting unit 3a and the optical axis L3 of the light receiving unit 4 intersect, that is, the detection region A1 where the irradiation range S1 of the irradiation light and the light reception range S3 of the received light overlap. Irradiation light is scattered by the smoke inside, and a part of the scattered light enters the light receiving unit 4. Further, when smoke flows into the detection region A2 where the optical axis L2 of the light emitting unit 3b and the optical axis L3 of the light receiving unit 4 intersect, that is, the detection region A2 where the irradiation range S2 of the irradiated light and the light receiving range S3 of the received light overlap. Irradiation light is scattered by the smoke in A 2, and a part of the scattered light enters the light receiving unit 4. As in the first embodiment, a light limiting member (not shown) for limiting the irradiation range S1 of the irradiation light is provided integrally with the light emitting units 3a and 3b so that the two detection areas A1 and A2 do not overlap. It has been. The emitted light of each light emission part 3a, 3b is irradiated to corresponding detection area | region A1, A2 through opening of a light limiting member. In addition, a light limiting member (not shown) for limiting the light receiving range S3 of the received light is provided integrally with the light receiving unit 4 so that the two detection regions A1 and A2 do not overlap with each other. The light enters the light receiving unit 4 through the opening of the light limiting member.

  Here, when an insect or dust enters the smoke sensing chamber 2, scattered light is generated by the insect or dust that has entered the detection area A1 or the detection area A2, and the light receiving unit 4 can receive the scattered light. There is sex. However, since it is unlikely that insects and dust will enter both detection areas A1 and A2 at the same time, the determination unit 5 determines that scattered light is detected only in one of the detection areas A1 and A2. Not judged as smoke. On the other hand, when smoke generated by a fire or the like enters the smoke detection chamber 2, the flow of smoke is controlled by the labyrinth wall 8 or the like so that the smoke flows into both the detection regions A1 and A2. , A2 determines that smoke is present only when scattered light is detected in both. As a result, erroneous detection due to insects, dust, and the like is unlikely to occur, and smoke can be reliably detected. In addition, since the light limiting member for limiting the light range is provided integrally with the light emitting units 3a, 3b and the light receiving unit 4, the light limiting member is provided separately from the light emitting units 3a, 3b and the light receiving unit 4. Compared to the above, the smoke detector 1 can be miniaturized. In addition, the optical design is easier than in the case where the light limiting member that causes stray light is provided separately from the light emitting units 3 a and 3 b and the light receiving unit 4. In this embodiment, the light limiting member is provided on both the light emitting side and the light receiving side. However, the range of light (either irradiated light or received light) can be limited so that a plurality of detection areas do not overlap. In this case, the light limiting member may be provided on only one of the light emitting side and the light receiving side.

  Here, since the optical axes L1 and L2 of the two light emitting units 3a and 3b are substantially parallel and obliquely intersect with the optical axis L3 of the light receiving unit 4, the optical axis L1 of the light emitting unit 3a and the light receiving unit The angle θ1 formed by the four optical axes L3 and the angle θ2 formed by the optical axis L2 of the light emitting unit 3b and the optical axis L3 of the light receiving unit 4 are different from each other. That is, the angles θ1 and θ2 formed by the optical axis of the light emitting unit and the optical axis of the light receiving unit are different from each other in the two detection regions A1 and A2. As a result, smoke having a large particle diameter is easily detected in the detection region A1 in which the angle between the optical axis of the light emitting unit and the optical axis of the light receiving unit is relatively large, and the optical axis of the light emitting unit and the optical axis of the light receiving unit are easily detected. In the detection area A2 where the angle formed is relatively small, smoke with a small particle diameter is easily detected.

  As shown in FIGS. 1 and 3, when two light emitting units 3a and 3b are arranged on the same side with respect to the optical axis L3 of the light receiving unit 4, the two detection areas A1 and A2 If the angle formed by the optical axis on the light emitting side is made different, the optical axis L2 of the light emitting unit 3b is arranged so as to obliquely intersect the optical axis L1 of the light emitting unit 3a. , A2 is wasted sparse. On the other hand, as shown in FIG. 4A, if the two light emitting portions 3a and 3b are arranged on both sides of the optical axis L3, the light emitting portions 3a and 3b are arranged so that the optical axes are parallel to each other. Thus, the angle formed between the optical axis on the light receiving side and the optical axis on the light emitting side can be made different in the detection areas A1 and A2. Accordingly, the two light emitting units 3a and 3b can be disposed close to each other, and a useless space between the detection areas A1 and A2 is reduced, and the overall size can be reduced.

  In the arrangement example shown in FIG. 4A, two light emitting units 3a and 3b are arranged for one light receiving unit 4. However, as shown in FIG. 4B, one light emitting unit 3 is arranged. Two light receiving portions 4a and 4b may be provided, and as described above, a useless space between the detection areas A1 and A2 can be reduced, and the overall size can be reduced.

  As described above, the smoke detector includes a smoke detection chamber, a light emitting unit, and a light receiving unit. The smoke sensing chamber suppresses the entrance of light from the outside and allows smoke to enter and exit. The light emitting unit emits light to a plurality (two in the above-described embodiment) of detection areas in the smoke sensing chamber. Direct light from the light emitting part does not enter the light receiving part, but scattered light due to smoke flowing into each detection region enters. In addition, a light limiting member that limits a light range so that a plurality of detection regions do not overlap is provided integrally with at least one of the light emitting unit and the light receiving unit.

  Thereby, when scattered light is detected by only a part of the plurality of detection regions by the light receiving unit, it can be determined that the light is not smoke but insects or dust, and erroneous detection due to insects or dust can be reduced. Furthermore, since the light limiting member that limits the light range so that the plurality of detection regions do not overlap is provided integrally with at least one of the light receiving unit and the light emitting unit, it is separate from the light receiving unit or the light emitting unit. Since the light limiting member can be made smaller than when the light limiting member is provided, the smoke detector 1 can be downsized. Further, optical design is facilitated as compared with the case where the light limiting member causing stray light is provided separately from the light receiving unit or the light emitting unit.

  In this smoke detector, it is also preferable that a plurality of light emitting units are provided for one light receiving unit, and the plurality of light emitting units respectively irradiate light to corresponding detection areas.

  Thereby, compared with the case where each of a some detection area is detected by the group of a light-receiving part and a light emission part, the number of light-receiving parts can be reduced and cost reduction can be aimed at.

  In this smoke detector, it is also preferable that a plurality of light receiving units are provided for one light emitting unit, and each of the plurality of light receiving units receives light from a corresponding detection region.

  Thereby, compared with the case where each of a some detection area is detected with the group of a light-receiving part and a light emission part, the number of light emission parts can be reduced and cost reduction can be aimed at. In addition, when a plurality of light emitting units are provided for one light receiving unit, it is necessary to detect the presence or absence of smoke in each detection region by turning on the light emitting units one by one. Since a plurality of light receiving sections are provided, the presence or absence of smoke in a plurality of detection areas can be detected simultaneously.

  In this smoke detector, it is also preferable that the angles formed by the optical axis of the light emitting unit and the optical axis of the light receiving unit are different from each other in each of the plurality of detection regions.

  As described above, the scattering characteristics of light due to smoke vary depending on the particle diameter. The larger the particle diameter, the larger the forward scattering component, and the smaller the particle diameter, the smaller the forward scattering component, depending on the scattering direction. There is a tendency that the difference in the scattering components becomes smaller. When the angle formed between the optical axis of the light emitting unit and the optical axis of the light receiving unit is different from each other in each of the plurality of detection regions, the angle formed between the optical axis of the light emitting unit and the optical axis of the light receiving unit is relatively large. In the detection region, by increasing the scattering component due to smoke having a large particle diameter, the output level of the light receiving unit can be increased, and smoke having a large particle diameter can be easily detected. In the detection region where the angle between the optical axis of the light emitting unit and the optical axis of the light receiving unit is relatively small, the difference between the scattering component due to smoke with a large particle size and the scattering component due to smoke with a small particle size is small. This makes it easier to detect smoke with a small particle size. Therefore, smoke having a relatively large particle diameter or smoke having a relatively small particle diameter is obtained by making the angle formed by the optical axis of the light emitting unit and the optical axis of the light receiving unit different from each other in each of the plurality of detection regions. Easy to detect.

  Further, in this smoke detector, any one of the light emitting unit and the light receiving unit is provided in a plurality, and the plurality of light emitting units or light receiving units provided on the plane including the optical axes of the light emitting unit and the light receiving unit are 1 It is also preferable that they are arranged on the same side with respect to the optical axis of only one light receiving part or light emitting part.

  Thereby, it is advantageous that only one light-receiving member or light-emitting unit is provided on one side with respect to the optical axis of the light-receiving unit or the light-emitting unit, which shields the incident light from the light-emitting unit from directly entering the light-receiving unit. There is.

  In this smoke detector, any one of the light emitting part and the light receiving part is provided in plural, and only one light emitting part or light receiving part provided on the plane including the optical axis of the light emitting part and the light receiving part is provided. It is also preferable that they are arranged on both sides with respect to the optical axis of the provided light receiving part or light emitting part.

  When multiple light emitting units or light receiving units are arranged on the same side with respect to the optical axis of only one light receiving unit or light emitting unit, the optical axis of the light emitting unit and the light receiving unit In order to make the angle formed with the optical axis different, the optical axes of a plurality of light emitting units or light receiving units must be arranged so as to intersect each other, and a wasteful space is created between the plurality of detection regions. End up. On the other hand, when a plurality of light emitting units or light receiving units are arranged on both sides of the optical axis of only one light receiving unit or light emitting unit, the optical axes of the plurality of light emitting units or light receiving units provided are Since it suffices to arrange them so as to be parallel to each other, a gap formed between a plurality of detection regions can be reduced, and the smoke detector can be downsized as a whole.

(Embodiment 4)
Since the smoke detector 1 of the present embodiment has the same configuration as the smoke detector 1 described in the first embodiment, the description thereof is omitted.

  In the present embodiment, as shown in FIG. 5, two light emitting units 3 a and 3 b are provided for one light receiving unit 4, irradiation ranges S <b> 1 and S <b> 2 by the light emitting units 3 a and 3 b, and a light receiving range S <b> 4 of the light receiving unit 4. The areas where are overlapped are defined as detection areas A1 and A2, respectively.

  The determination unit 5 has a function of controlling the light emission of the light emitting units 3 a and 3 b and a function of determining the presence or absence of smoke from the output of the light receiving unit 4. The determination unit 5 does not simultaneously emit a plurality of (two in the present embodiment) light emitting units 3a and 3b, and based on the output of the light receiving unit 4 in a state where each of the light emitting units 3a and 3b emits light individually. In addition, the state in the smoke sensing chamber 2 is determined.

  Thereby, it is not necessary to provide a set of light emitting units and light receiving units for each of the plurality of detection regions, and the state of the plurality of detection regions can be monitored by one light receiving unit 4.

  In addition, the determination unit 5 sets the detection areas A1 and A2 at a time interval shorter than a movement time necessary for moving foreign substances (such as dust and insects) other than smoke between the detection areas A1 and A2. The corresponding light emitting units 3a and 3b emit light. And the determination part 5 exceeds the threshold value in the state which made any light emission part (light emission part 3a or light emission part 3b) light-emit, and another light emission part (light emission part 3b or light emission). When the output of the light receiving unit 4 in a state where the unit 3a is caused to emit light is smaller than the threshold value, it is determined that a foreign substance other than smoke has entered the smoke sensing chamber 2.

  As shown in FIG. 5, a case is considered where dust D that has entered the smoke sensing chamber 2 from the outside moves from the detection area A1 to the detection area A2. As shown in FIG. 6B, when the light emission interval of the light emitting units 3a and 3b is set to a time T2 that is longer than the movement time necessary for the movement of foreign substances other than smoke between the detection areas A1 and A2. There is a possibility that the output of the light receiving unit 4 exceeds the threshold value both when the light emitting unit 3a is lit and when the light emitting unit 3b is lit. In this case, the determination unit 5 erroneously detects that smoke has entered the smoke sensing chamber 2 because the output of the light receiving unit 4 exceeds the threshold value both when the light emitting unit 3a is lit and when the light emitting unit 3b is lit. End up. Therefore, it is preferable to set the light emission interval of the light emitting units 3a and 3b to a time shorter than the moving time required for foreign substances other than smoke to move between the detection areas A1 and A2. As shown in FIG. 6A, if the light emission interval of the light emitting units 3a and 3b is set to a time T1 shorter than the moving time, the dust D is detected in the detection area A1 until the light emission interval T1 elapses. Cannot move in. Therefore, even if the output of the light receiving unit 4 when the light emitting unit 3a emits light exceeds the threshold value because the dust D has entered the detection region A1, the dust D is detected in the detection region A2 until the light emission interval T1 elapses. Therefore, the output of the light receiving unit 4 when the light emitting unit 3b emits light does not exceed the threshold value. Therefore, when foreign matter (dust, insects, etc.) other than smoke enters the inside of the smoke detection chamber 2, the output of the light receiving unit 4 has a threshold value both when the light emitting unit 3a emits light and when the light emitting unit 3b emits light. Therefore, the possibility that the determination unit 5 erroneously detects that smoke has entered can be reduced.

  In addition, the determination unit 5 causes the corresponding light emitting units 3a and 3b to emit light at a time interval shorter than the movement time necessary for movement of foreign substances other than smoke between the plurality of detection areas A1 and A2. Then, the determination unit 5 determines that smoke has entered the smoke detection chamber 2 when all the outputs of the light receiving unit 4 in the state where each of the plurality of light emitting units 3a and 3b individually emit light exceeds the threshold value. To do.

  In the period W1 of FIG. 7, when the light emitting units 3a and 3b emit light, no foreign matter has entered the detection areas A1 and A2, and the output of the light receiving unit 4 is lower than the threshold value. It is determined that no foreign matter such as smoke or insects / dust has entered the chamber 2. Also, during the period W2, when the light emitting unit 3a emits light, foreign matter has entered the detection area A1, so the output of the light receiving unit 4 exceeds the threshold value, but when the light emitting unit 3b emits light, foreign matter has entered the detection area A2. Therefore, the output of the light receiving unit 4 is below the threshold value. Therefore, since the output of the light receiving unit 4 exceeds the threshold only when the light emitting unit 3a emits light, the determination unit 5 has foreign matter (dust, insects, etc.) other than smoke entering the smoke sensing chamber 2. Is determined. In the period W3, the output of the light receiving unit 4 exceeds the threshold when both the light emitting units 3a and 3b emit light. In this case, the determination unit 5 determines that smoke has entered the smoke sensing chamber 2. When smoke accompanying a fire enters the smoke detection chamber 2, the smoke is present in the smoke detection chamber 2 substantially uniformly, so that the determination unit 5 causes the light emitting units 3a and 3b to emit light individually. When all the outputs of the light receiving unit 4 exceed the threshold value, it is determined that smoke has entered the smoke sensing chamber 2, and false detection can be reduced.

  Further, as shown in FIG. 7, the determination unit 5 causes the plurality of light emitting units 3a and 3b to emit light intermittently at a predetermined period T3, and performs a determination operation based on the output of the light receiving unit 4 when the light emitting units 3a and 3b emit light. The power consumption can be reduced compared to the case where the light emitting units 3a and 3b are kept on.

  In addition, when the determination unit 5 does not detect that a foreign object has entered the smoke sensing chamber 2, only one of the light emitting units 3a emits light, and the output of the light receiving unit 4 emits light when the light emitting unit 3a emits light. When the threshold value is exceeded, it is also preferable to cause the other light emitting unit 3b to emit light. Here, when the light emitting unit 3b is caused to emit light, the determination unit 5 causes the light emitting unit 3b to emit light at a time interval shorter than the moving time necessary for the movement of foreign substances other than smoke between the detection areas A1 and A2. ing.

  When smoke enters the inside of the smoke detection chamber 2, smoke is detected in both the detection areas A1 and A2, and therefore when the one light emitting unit 3a emits light, the output of the light receiving unit 4 must not exceed the threshold value. In this case, it can be determined that smoke does not enter the inside of the smoke detection chamber 2. Therefore, as shown in FIG. 8, the determination unit 5 causes only one of the light emitting units (for example, the light emitting unit 3a) to emit light during the period W4 during which no smoke is detected, and the light receiving unit 4 when the light emitting unit 3a emits light. When the output exceeds the threshold (periods W5 and W6), the other light emitting units 3b are also caused to emit light. If the output of the light receiving unit 4 does not exceed the threshold when the light emitting unit 3b emits light (period W5), the determining unit 5 determines that a foreign substance other than smoke has entered, and the light receiving unit 4b emits light when the light emitting unit 3b emits light. When the output exceeds the threshold (period W6), the determination unit 5 determines that smoke has entered. Thus, in a non-detected state where no foreign matter such as smoke, dust, or insects is detected, power can be saved by causing only one of the light emitting units to emit light. Further, when the output of the light receiving unit 4 exceeds the threshold value in a state where the light emitting unit 3a emits light, the determination unit 5 causes the other light emitting unit 3b to emit light and captures the output of the light receiving unit 4, and smoke is generated based on the output. Therefore, it is possible to reduce the possibility of erroneously detecting foreign matter such as smoke and insects as smoke.

  By the way, as shown in FIG. 9, the crossing angles θ1 and θ2 formed by the optical axes L1 and L2 of the light emitting units 3a and 3b and the optical axis L3 of the light receiving unit 4 are set to different angles. 9, the intersection formed by the optical axis L2 of the light emitting unit 3b and the optical axis L3 of the light receiving unit 4 is larger than the crossing angle θ1 formed by the optical axis L1 of the light emitting unit 3a and the optical axis L3 of the light receiving unit 4. The angle θ2 is smaller (θ1> θ2).

  As described in the first embodiment, when light hits smoke particles, it has been found that the power distribution of scattered light varies depending on the size of the particle diameter. Moreover, the white smoke (smoke) generated at the initial stage of the fire has a larger smoke particle size than the black smoke generated during the expansion of combustion. Therefore, the power distribution of the scattered light due to the white smoke is a power distribution in which the forward scattered component is large as shown in FIG. 2B, and the power distribution of the scattered light due to the black smoke is as shown in FIG. As shown, the power distribution is scattered substantially uniformly in all directions. In addition, since black smoke has a higher light attenuation rate than white smoke, if the smoke density is the same, the intensity of scattered light incident on the light receiving unit 4 is smaller for black smoke than for white smoke. Become.

  FIG. 10A shows the relationship between the scattered light intensity incident on the light receiving unit 4 when black smoke enters and the smoke density, and FIG. 10B enters the light receiving unit 4 when white smoke enters. The relationship between scattered light intensity and smoke density is shown. Further, a characteristic E in FIGS. 10A and 10B shows the scattered light intensity in a state where the light emitting unit 3a having a relatively large crossing angle emits light, and a characteristic F in FIGS. The scattered light intensity in a state where the light emitting part 3b having a relatively small crossing angle emits light is shown.

  Here, in the case of white smoke, the intensity of scattered light incident on the light receiving unit 4 is higher when light is emitted from the light emitting unit 3b having an acute crossing angle than when the light emitting unit 3a has an obtuse crossing angle. It is significantly smaller. On the other hand, in the case of black smoke, since the change in scattered light intensity due to the crossing angle is smaller than in the case of white smoke, the light is incident on the light receiving unit 4 when the light emitting unit 3a emits light and when the light emitting unit 3b emits light. The difference in scattered light intensity is smaller than that of white smoke. Therefore, in the case of white smoke when the smoke density is X1, the ratio of the output c3 of the light receiving unit 4 in the light emitting state of the light emitting unit 3b to the output c4 of the light receiving unit 4 in the light emitting state of the light emitting unit 3a is (c3 / C4). On the other hand, when the smoke density is X1, in the case of black smoke, the ratio of the output c1 of the light receiving unit 4 in the light emitting state of the light emitting unit 3b to the output c2 of the light receiving unit 4 in the light emitting state of the light emitting unit 3a is (c1 / C2), which is larger than the ratio (c3 / c4) in the case of white smoke.

  Therefore, in the determination unit 5, the light reception in a state where the light emitting unit 3b having a relatively small crossing angle emits light with respect to the output of the light receiving unit 4 in a state in which the light emitting unit 3a having a relatively large crossing angle emits light. The ratio of the output of the part is compared with a predetermined reference value. When the above ratio becomes larger than the reference value, the determination unit 5 determines that black smoke has entered the smoke detection chamber 2, and the type of smoke that has entered the smoke detection chamber 2 (white smoke) Or black smoke). And when it is discriminated as black smoke, since the amount of light incident on the light receiving unit 4 is lower when black smoke enters than when white smoke enters, the determination unit 5 sets a threshold for determining the presence or absence of smoke. Even in the case of black smoke that has been reduced and the output of the light receiving unit 4 is reduced, the presence of smoke can be reliably detected.

  Moreover, in the determination part 5, it is also preferable to make at least any one among the light emission time and light emission amount of the light emission part 3b with a relatively small cross angle larger than the light emission part 3a with a relatively large cross angle. In the light emitting unit 3b having a relatively small crossing angle, since the scattering component due to smoke is smaller than that of the light emitting unit 3a having a relatively large crossing angle, the output of the light receiving unit 4 when white smoke flows in is considered to be small. . Accordingly, in the determination unit 5, at least one of the light emission time and the light emission amount of the light emitting unit 3b is set larger than the light emitting unit 3a, and thereby the output of the light receiving unit 4 at the time of light emission of the light emitting unit 3b. Therefore, smoke detection omission can be reduced.

  The operation in this case will be described with reference to FIG. In the example of FIG. 11, since the crossing angle is small, the amount of light emitted from the light emitting unit 3b is increased by increasing the power supplied to the light emitting unit 3b whose output is smaller than that of the light emitting unit 3a.

  In period W7 in FIG. 11, since no foreign substance such as smoke has entered the smoke sensing chamber 2, no signal is output from the light receiving section 4 when the light emitting sections 3a and 3b are turned on.

  In the period W8 in FIG. 11, white smoke enters the inside of the smoke detection chamber 2, and in the case of white smoke, the scattered light component is lower when the crossing angle is smaller than when the crossing angle is large. By making the light emission amount of the light emitting unit 3b having a small corner larger than that of the light emitting unit 3a, the output of the light receiving unit 4 is made substantially the same when the light emitting unit 3a emits light and when the light emitting unit 3b emits light.

  In the period W9 in FIG. 11, black smoke enters the inside of the smoke detection chamber 2, and in the case of black smoke, the size of the scattered light component does not change much depending on the crossing angle. Accordingly, the output of the light receiving unit 4 when the light emitting unit 3a emits light is larger than the output of the light receiving unit 4 when the light emitting unit 3a emits light. In the case of black smoke, the amount of attenuation of light is larger than that of white smoke. Therefore, the output of the light receiving unit 4 when the light emitting unit 3a emits light is lower when black smoke enters than when white smoke enters. doing.

  As described above, even in the case of white smoke in which the size of the scattered light component due to the crossing angle changes by increasing the light emission amount (light emission time or light emission amount) of the light emitting unit 3b having a small crossing angle, The output of the light receiving unit 4 at the time of light emission can be increased, and smoke detection omission can be suppressed.

  Further, in a non-detection state in which it is not detected that foreign matter such as smoke, dust, or insects has entered the inside of the smoke detection chamber 2, the determination unit 5 emits any one light emitting unit as shown in FIG. However, it is preferable to emit only the light emitting portion 3a having a relatively small crossing angle. By causing only one of the plurality of light emitting units 3a and 3b to emit light, power consumption can be reduced. Further, when the light emission amount of the light emitting unit 3b is increased as shown in FIG. 11, the power consumption can be further reduced by causing only the light emitting unit 3a having a small light emission amount to emit light.

  The operation in this case will be described with reference to FIG. In the periods W10 and W11 in FIG. 12, no smoke enters the smoke sensing chamber 2, and the output of the light receiving unit 4 when the light emitting unit 3a emits light is smaller than the threshold value. The light emitting unit 3b is not turned on. On the other hand, in the period W12 of FIG. 12, black smoke has entered the inside of the smoke sensing chamber 2, and the determination unit 5 determines that the output of the light receiving unit 4 at the time of light emission of the light emitting unit 3a exceeds the threshold value. If the output of the light receiving unit 4 at the time of light emission of the light emitting unit 3b exceeds the threshold value, it is determined that smoke has entered.

  Thus, in the non-detection state, since the determination part 5 lights only the light emission part 3a, power consumption can be reduced. Further, when the light emission amount of the light emission unit 3b having a smaller crossing angle than the light emission unit 3a is larger than that of the light emission unit 3a, only the light emission unit 3a having a smaller light emission amount in the non-detection state is turned on. Electric power can be further reduced. In addition, when the output of the light receiving unit 4 exceeds the threshold value with only the light emitting unit 3a turned on, the determination unit 5 turns on the light emitting units 3a and 3b separately and turns on the light emitting units 3a and 3b, respectively. Since it is determined whether or not smoke is present based on the output of the output unit 4 in the state where it has been, the presence or absence of smoke can be reliably detected.

  Here, the above operations are summarized by a flowchart as shown in FIG. First, the determination unit 5 emits the light emitting unit 3a having a relatively large intersection angle θ1 with the optical axis of the light receiving unit 4 (step ST1), and compares the output of the light receiving unit 4 at this time with a predetermined threshold value. Then, it is determined whether or not the entry of a foreign object has been detected (step ST2). Here, if the output of the light receiving unit 4 is smaller than a predetermined threshold (no in step ST2), the determination unit 5 determines that nothing has entered the smoke sensing chamber 2 (step ST3). On the other hand, if the output of the light receiving unit 4 is larger than the predetermined threshold (yes in step ST2), the determining unit 5 determines that something has entered the inside of the smoke sensing chamber 2, and causes the light emitting unit 3b to emit light. (Step ST4), the output of the light receiving unit 4 at this time is compared with a predetermined threshold (Step ST5).

  Here, if the output of the light receiving unit 4 exceeds the threshold value (yes in step ST5), the determination unit 5 determines the output of the light receiving unit 4 when the light emitting unit 3a emits light and the light receiving unit when the light emitting unit 3b emits light. 4 is compared with the output of 4 (step ST6). And if the output of the light receiving part 4 at the time of light emission of the light emitting part 3b is smaller than the output of the light receiving part 4 at the time of light emission of the light emitting part 3a (yes of step ST6), the determination part 5 is placed in the smoke sensing chamber 2. It is determined that black smoke has entered (step ST7). Furthermore, the determination part 5 compares the output of the light-receiving part 4 at the time of light emission of the light-emitting part 3b, and the alert threshold value at the time of a black smoke fire (step ST8). Here, if the output of the light receiving unit 4 exceeds the alarm threshold for black smoke fire (yes in step ST8), the determination unit 5 determines that smoke due to fire has entered the smoke sensing chamber 2 (step ST8). ST9). If the output of the light receiving unit 4 is smaller than the alarm threshold for black smoke fire (no in step ST8), the determination unit 5 determines that thin smoke has entered the smoke sensing chamber 2 (step ST12).

  If the output of the light receiving unit 4 at the time of light emission of the light emitting unit 3b is larger than the output of the light receiving unit 4 at the time of light emission of the light emitting unit 3a in the determination at step ST6 (no at step ST6), the determination unit 5 It is determined that white smoke has entered the smoke sensing chamber 2 (step ST10). Further, the determination unit 5 compares the output of the light receiving unit 4 during light emission of the light emitting unit 3b with the alarm threshold value during white smoke fire (step ST11), and the output of the light receiving unit 4 is during white smoke fire. Is exceeded (step ST11: yes), it is determined as smoke due to fire (step ST9). If the output of the light receiving unit 4 at the time of light emission of the light emitting unit 3b is larger than the output of the light receiving unit 4 at the time of light emission of the light emitting unit 3a in the determination of step ST11 (no in step ST11), foreign matter other than smoke ( It is determined that dust or insects have entered the smoke sensing chamber 2 (step ST13). In step ST5, if the output of the light receiving unit 4 is less than or equal to the threshold value, it is determined that foreign matter (dust, insects, etc.) other than smoke has entered the smoke sensing chamber 2 (step ST13).

(Embodiment 5)
Since the smoke detector 1 of the present embodiment has the same configuration as the smoke detector 1 described in the second embodiment, the description thereof is omitted.

  In the present embodiment, as shown in FIG. 14, two light receiving units 4 a and 4 b are provided for one light emitting unit 3, and the light receiving ranges S 3 and S 4 of the light receiving units 4 a and 4 b and the irradiation range S 1 by the light emitting unit 3. The areas where each overlaps are defined as detection areas A1 and A2, respectively.

  The determination unit 5 has a function of controlling the light emission of the light emitting unit 3 and a function of determining the presence or absence of smoke from the outputs of the light receiving units 4a and 4b. The determination unit 5 operates the light receiving units 4a and 4b at the same time with the light emitting unit 3 emitting light, and simultaneously captures the outputs of the light receiving units 4a and 4b, and detects smoke based on the outputs of the light receiving units 4a and 4b. The state in the chamber 2 is determined.

  That is, in the present embodiment, a plurality of light receiving units 4a and 4b are provided for one light emitting unit 3, and the plurality of light receiving units 4a and 4b receive light from the corresponding detection areas A1 and A2, respectively. . Thereby, it is not necessary to provide a set of light emitting units and light receiving units for each of the plurality of detection regions, and the state of the plurality of detection regions A1 and A2 can be monitored by one light emitting unit 3.

  Here, in the present embodiment, the plurality of light receiving units 4 a and 4 b are arranged on the same side with respect to the optical axis of the light emitting unit 3 on a plane including the optical axes of the plurality of light receiving units 4 a and 4 b and the light emitting unit 3. Has been.

  This eliminates the need for providing a plurality of light-shielding walls that cause stray light, since only one light-shielding wall is required to shield the radiated light from the light-emitting part 3 from directly entering the light-receiving parts 4a and 4b. Design can be easily performed.

  As described in the third embodiment, the plurality of light receiving units 4 a and 4 b are arranged on both sides with respect to the optical axis of the light emitting unit 3 on the plane including the optical axes of the plurality of light receiving units 4 a and 4 b and the light emitting unit 3. It is also preferable to arrange them in

  If the plurality of light receiving parts 4a and 4b are arranged on both sides with respect to the optical axis of the light emitting part 3, the light receiving parts 4a and 4b are arranged so that their optical axes are parallel to each other, thereby detecting the detection region A1. , A2 can make the angle between the optical axis on the light receiving side and the optical axis on the light emitting side different. Therefore, even when it is desired to make the angle between the optical axis on the light receiving side and the optical axis on the light emitting side different in the detection areas A1 and A2, the plurality of light receiving parts 4a and 4b can be arranged close to each other, and the detection areas A1 and A2 As a result, the wasteful space between the two can be reduced, and the overall size can be reduced.

  Moreover, the determination part 5 takes in the output of several light-receiving part 4a, 4b simultaneously, and determines the state in the smoke detection chamber 2 based on the output of several light-receiving part 4a, 4b, and one light emission The unit 3 can monitor the states of the plurality of detection areas A1 and A2.

  Here, when the determination unit 5 simultaneously captures the outputs of the plurality of light receiving units 4a and 4b, the outputs of some of the light receiving units exceed the threshold value, and the outputs of the other light receiving units are smaller than the threshold value, other than smoke Is determined to have entered the smoke sensing chamber 2.

  When smoke enters the inside of the smoke detection chamber 2, the output of all the light receiving parts 4a and 4b is expected to increase. However, when dust or insects enter the inside of the smoke detection chamber 2, a plurality of detection areas are detected. The possibility that dust and insects enter A1 and A2 at the same time is expected to be low. For example, when only the output of the light receiving unit 4a exceeds the threshold value and the output of the light receiving unit 4b is smaller than the threshold value as in the period W14 in FIG. 15, the determination unit 5 determines that foreign matter other than smoke (dust, insects, etc.) 2 is determined to have entered, and the possibility of erroneous determination that smoke has entered can be reduced.

  Note that when the outputs of the light receiving units 4a and 4b are both lower than the threshold value as in the period W13 in FIG. 15, the determination unit 5 determines that the output of the light receiving units 4a and 4b simultaneously received is below the threshold value. It is determined that nothing has entered the sensing chamber 2.

  In addition, as in the periods W15 and W16 of FIG. 15, when both the outputs of the light receiving units 4a and 4b that have been simultaneously captured exceed the threshold value, the determination unit 5 determines that smoke has entered the smoke sensing chamber 2. To do.

  Here, the angle θ1 formed by the optical axis of the light receiving unit 4a and the optical axis of the light emitting unit 3 is different from the angle θ2 formed by the optical axis of the light receiving unit 4b and the optical axis of the light emitting unit 3. 3 and light receiving portions 4a and 4b are arranged. In the present embodiment, the angle θ2 formed by the optical axis of the light receiving unit 4b and the optical axis of the light emitting unit 3 is smaller than the angle θ1 formed by the optical axis of the light receiving unit 4a and the optical axis of the light emitting unit 3. ing. When white smoke having a relatively large particle diameter enters the inside of the smoke sensing chamber 2, the light receiving unit 4b having a small crossing angle has a smaller incident light amount than the light receiving unit 4a having a large crossing angle. Since the sensitivity of the light receiving unit 4b is set higher than that of the light receiving unit 4a, the output of the light receiving unit 4a and the output of the light receiving unit 4b are substantially the same in the period W15. On the other hand, when black smoke enters, the incident light amounts of the light receiving portions 4a and 4b become substantially the same, so that the output of the light receiving portion 4b is output in the period W16 by the amount that the sensitivity of the light receiving portion 4b is set higher. Is getting bigger.

  Thereby, in the period W15 in which the output of the light receiving unit 4a and the output of the light receiving unit 4b are substantially the same, the output of the light receiving unit 4b having a relatively small crossing angle with respect to the output of the light receiving unit 4a having a relatively large crossing angle. Is smaller than a predetermined reference value, the determination unit 5 determines that white smoke has entered the smoke sensing chamber 2. In the period W16 in which the output of the light receiving unit 4a is smaller than the output of the light receiving unit 4b, the ratio of the output of the light receiving unit 4b having a relatively small crossing angle to the output of the light receiving unit 4a having a relatively large crossing angle. However, since it is larger than the predetermined reference value, the determination unit 5 determines that black smoke has entered the smoke sensing chamber 2.

  By the way, the determination unit 5 determines whether or not smoke has entered the smoke sensing chamber 2 by comparing the output of the light receiving units 4a and 4b with the threshold value. If it is determined that black smoke has entered, it is also preferable to lower the threshold value.

  In the case of black smoke, the light attenuation rate is larger than that of white smoke. For this reason, when black smoke enters, the output levels of the light receiving parts 4a and 4b become smaller than when white smoke enters. Therefore, when it is determined that black smoke has entered, the determination unit 5 can suppress the smoke detection omission by reducing the threshold value for determining the presence or absence of smoke.

  In addition, the determination unit 5 operates only one of the light receiving units 4a and 4b in a state where it has not detected that a foreign object has entered the inside of the smoke detection chamber 2, and takes in an output. When the captured output exceeds the threshold, the other light receiving unit 4b is operated to capture the output.

  Thereby, in the state where smoke is not detected, only one of the light receiving units 4a is operated and the operation of the other light receiving units 4b is stopped, so that power consumption can be reduced. When the output of the light receiving unit 4a exceeds the threshold value, the determination unit 5 operates the plurality of light receiving units 4a and 4b to determine whether smoke is present based on the outputs of the light receiving units 4a and 4b. Therefore, the presence or absence of smoke can be reliably detected.

  In the above-described embodiment, two detection areas are set in the smoke detection chamber. However, the light receiving unit and the light emitting unit may be configured so that three or more detection areas exist. Further, in the present embodiment, a plurality of detection regions are provided by providing a plurality of light emitting units for one light receiving unit or by providing a plurality of light receiving units for one light emitting unit. A scattered light may be detected by providing one light receiving part and one light emitting part in each of the plurality of detection regions.

  In the above-described embodiment, the smoke sensing chamber 2 is structured so as to be covered with the labyrinth wall 8 as shown in FIG. 1. The present invention is applied to such a smoke sensing chamber 2. It does not limit what you do. A smoke detection chamber not using a structure called a labyrinth wall in the field of fire detectors without being bound by FIG. 1, that is, a smoke detection chamber without a labyrinth wall and having a hole for circulation to the outside air, The present invention may be applied to this.

DESCRIPTION OF SYMBOLS 1 Smoke detector 2 Smoke detection chamber 3a, 3b Light emission part 4 Light reception part 5 Judgment part 11,12 Light limiting member A1, A2 Detection area S1, S2 Irradiation range S3 Light reception range

Claims (17)

A smoke sensing chamber that suppresses the entry of light from outside and allows smoke to enter and exit;
A plurality of light emitting units that respectively emit light into the smoke sensing chamber;
A light receiving unit in which a light receiving range is set in the smoke sensing chamber ;
And a determining section for determining whether or not smoke enters the smoke chamber based on an output of the light receiving portion,
The light receiving unit is configured so that direct light from the plurality of light emitting units does not enter,
A plurality of areas where the irradiation ranges of the plurality of light emitting units respectively overlap with the light receiving range of the light receiving unit become a plurality of detection regions,
A smoke detector, wherein a light limiting member is provided integrally with at least one of the plurality of light emitting units and the light receiving unit so as to limit a light range so that the plurality of detection regions do not overlap. . 2. The smoke detector according to claim 1, wherein the crossing angle formed by the optical axis of each of the light emitting units and the optical axis of the light receiving unit is set to be different from each other. The plurality of light emitting units are arranged on the same side with respect to the optical axis of the light receiving unit on a plane including the optical axes of the plurality of light emitting units and the light receiving unit. The smoke detector described. The plurality of light emitting units are arranged on both sides with respect to the optical axis of the light receiving unit on a plane including the optical axes of the plurality of light emitting units and the light receiving unit. Smoke detector. The determination unit controls light emission of the plurality of light emitting units so that the plurality of light emitting units do not emit light simultaneously,
  The said determination part determines the state in the said smoke sensing chamber based on the output of the said light-receiving part in the state which light-emitted each of the said several light emission part separately. The smoke detector according to any one of the above. The determination unit causes the light emitting unit corresponding to the detection region to emit light at a time interval shorter than a movement time necessary for movement of foreign substances other than smoke between the plurality of detection regions,
  The determination unit is configured such that an output of the light receiving unit in a state where any one of the light emitting units emits light exceeds a threshold value, and an output of the light receiving unit in a state where another light emitting unit emits light is the threshold value. 6. The smoke detector according to claim 5, wherein if it is smaller than that, it is determined that a foreign substance other than smoke has entered the smoke detection chamber. The determination unit causes the corresponding light emitting unit to emit light at a time interval shorter than a movement time necessary for movement of foreign substances other than smoke between the plurality of detection regions,
  The determination unit determines that smoke has entered the smoke sensing chamber when all the outputs of the light receiving unit in a state where each of the plurality of light emitting units individually emits light exceeds a threshold value. The smoke detector according to claim 5. The smoke detector according to claim 5, wherein the determination unit causes the plurality of light emitting units to emit light intermittently and performs a determination operation based on an output of the light receiving unit. The determination unit intermittently emits one of the light emitting units in a non-detection state,
  When the output of the light receiving unit exceeds a threshold value in a state where any one of the light emitting units emits light, the determination unit determines from the moving time required for foreign substances other than smoke to move between the plurality of detection regions. 9. The smoke detector according to claim 8, wherein each of the other light emitting units emits light individually at a short time interval. The crossing angle formed by the optical axis of each of the light emitting units and the optical axis of the light receiving unit is set to be different from each other,
  The determination unit determines whether smoke has entered the smoke sensing chamber by comparing the output of the light receiving unit and a threshold value.
  The ratio of the output of the light receiving unit when the light emitting unit emits light with a relatively small cross angle to the output of the light receiving unit with the light emitting unit emitting light with a relatively large crossing angle is: The smoke according to any one of claims 1 to 9, wherein when the reference value is larger than a predetermined reference value, the determination unit determines that smoke that has entered the smoke detection chamber is black smoke, and reduces the threshold value. sensor. The determination unit is characterized in that at least one of a light emission time and a light emission amount of the light emitting unit having a relatively small crossing angle is made larger than that of the light emitting unit having a relatively large crossing angle. The smoke detector according to claim 10. The determination unit emits only the light emitting unit having a relatively large intersection angle in a non-detection state,
  When the output of the light receiving unit exceeds a threshold value in a state where the light emitting unit emits light, the determination unit has a time interval shorter than a moving time required for foreign substances other than smoke to move between the plurality of detection regions. The smoke detector according to claim 10 or 11, wherein the other light emitting unit emits light. A smoke sensing chamber that suppresses the entry of light from outside and allows smoke to enter and exit;
  A light emitting unit that emits light into the smoke sensing chamber;
  A plurality of light receiving portions each having a light receiving range set in the smoke sensing chamber;
  A determination unit that determines whether smoke has entered into the smoke sensing chamber based on outputs of the plurality of light receiving units,
  Each of the plurality of light receiving units is configured so that direct light from the light emitting unit is not incident thereon,
  A plurality of areas where the irradiation range of the light emitting unit respectively overlaps the light receiving range of the plurality of light receiving units becomes a plurality of detection regions
  A light limiting member that limits the light range so that the plurality of detection regions do not overlap is provided integrally with at least one of the light emitting unit and the plurality of light receiving units,
  The crossing angle formed by the optical axis of each light receiving part and the optical axis of the light emitting part is set to be different from each other,
  The determination unit simultaneously captures the outputs of the plurality of light receiving units, compares the output of the plurality of light receiving units with a threshold value, and if all the outputs of the plurality of light receiving units exceed the threshold value, the smoke Judging that smoke has entered the sensing chamber,
  When the ratio of the output of the light receiving unit having a relatively small cross angle to the output of the light receiving unit having a relatively large cross angle is greater than a predetermined reference value, the determination unit is placed in the smoke sensing chamber. A smoke detector characterized in that the smoke that has entered is identified as black smoke and the threshold value is lowered. The plurality of light receiving units are arranged on the same side with respect to the optical axis of the light emitting unit on a plane including the optical axis of the light emitting unit and the optical axes of the plurality of light receiving units. 13. The smoke detector according to 13. The plurality of light receiving units are arranged on both sides with respect to the optical axis of the light emitting unit on a plane including the optical axis of the light emitting unit and the optical axes of the plurality of light receiving units. The smoke detector described. The determination unit simultaneously captures outputs of the plurality of light receiving units, and outputs of some of the light receiving units exceed the threshold value, and outputs of other light receiving units are smaller than the threshold value, other than smoke The smoke detector according to any one of claims 13 to 15, wherein a foreign object is determined to have entered the smoke detection chamber. The determination unit captures an output by operating only one of the plurality of light receiving units in a state where it is not detected that a foreign object has entered the smoke sensing chamber, and the captured output is the The smoke detector according to any one of claims 13 to 15, wherein when the threshold value is exceeded, the other light receiving unit is operated to capture an output.

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