JP2019067020A - smoke detector - Google Patents

Abstract

To provide a compact smoke detector capable of discriminating the kind of smoke, achieving stable and highly accurate smoke detection processing by using one light source, and detecting smoke with high accuracy.SOLUTION: A smoke detector includes a light emitting element 11, a light receiving element 12, and reflection parts 13. The light emitting element emits light toward an outer side of a smoke detection space. The pair of reflection parts 13 capable of switching and controlling a reflection state and a non-reflection state are provided, so as to enable acquisition of two types of smoke density values with different scattering angles while one light emitting element is included.SELECTED DRAWING: Figure 1

Description

  The present invention relates to smoke detectors.

  As a prior art, there is a smoke detector provided with a light emitting element, a light receiving element, and a mirror in a smoke detector (see, for example, Patent Document 1). More specifically, in the smoke detector described in Patent Document 1, a mirror member having a mirror surface capable of reflecting light is disposed in the smoke detection unit, and the irradiation light emitted from the light emitting element is reflected by the mirror member. The light is reflected to reach the detection area. The scattered light is allowed to reach the light receiving element only when the reflected light is scattered due to the generation of smoke.

  Therefore, the light emitting element and the light receiving element can be disposed closer to each other than in the prior art, for example, the optical axes are disposed parallel to each other. As a result, it is possible to miniaturize the smoke detection unit and hence to miniaturize the entire smoke sensor.

JP, 2008-242627, A

  However, the prior art has the following problems. The smoke detected by the smoke detector is not uniform, and the nature of the scattered light generation at the smoke detection section differs depending on the type of smoke. Therefore, in the case of the prior art in which the light emitting element is provided near the center of the smoke detection part, depending on the type of smoke entering the smoke detection part, the irradiation light from the light emitting element to the mirror member produces unexpected scattered light The detection accuracy may become unstable.

  Furthermore, in order to determine the type of smoke, it is conceivable to use a plurality of light emitting elements. However, when there are a plurality of light emitting elements, the number of parts arranged in the smoke detection part is increased, so that not only the smoke detection part becomes large, but also the detection accuracy may become unstable due to the variation of the characteristic of each part. There is.

  The present invention has been made to solve the problems as described above, and has an object to miniaturize a sensor and obtain a smoke sensor capable of detecting smoke with high accuracy.

  The smoke sensor according to the present invention includes a light emitting element for emitting light, a reflecting portion for reflecting light from the light emitting element toward the smoke detection space, and light reflected by the reflecting portion scattered by the smoke which has entered the smoke detection space A smoke detector including a light receiving element for outputting a signal according to the received amount of scattered light obtained by the light source, the light emitting element emitting light toward the outside of the smoke detection space .

  According to the present invention, the light emitting element is directed outward, and the light from the light emitting element is reflected by the reflecting portion, and the light can be irradiated to the smoke detection space. As a result, since the light emitted from the light emitting element can be emitted outward, it is possible to obtain a smoke sensor in which scattered light is unlikely to enter the light receiving element even if smoke enters between the light emitting element and the mirror member. Furthermore, the smoke sensor can be miniaturized, and a smoke sensor capable of detecting smoke with high accuracy can be obtained.

It is cross-sectional explanatory drawing which shows the structure in the smoke detector in Embodiment 1 of this invention. It is a block diagram of smoke detector 1 in Embodiment 1 of the present invention. It is the figure which showed the structural example of the reflection part used with the smoke detector in Embodiment 1 of this invention.

  Hereinafter, the smoke detector of the present invention will be described using the drawings.

Embodiment 1
FIG. 1 is a cross-sectional explanatory view showing the configuration in the smoke detector in the first embodiment of the present invention. As shown in FIG. 1, the wall body 14 has a cross section in the axial direction of the smoke detector, for example, a plurality of labyrinth members 14a having a substantially J shape (J shape having a horizontal bar at the head) at the same intervals and at the same circle. By arranging on the circumference, it is comprised by the labyrinth structure formed in a substantially cylindrical shape. By forming the wall body 14 with a labyrinth structure, it is possible to allow the flow of smoke into the interior and prevent the incidence of external light.

  One light emitting element 11, one light receiving element 12, and two reflection parts 13 (1) and 13 (2) are disposed in the smoke detection part 10 inside the labyrinth structure. The light emitting element 11 is provided in the smoke detector 10 so as to be close to the wall 14 and emits light toward the wall 14, that is, toward the outside corresponding to the direction in which the labyrinth member 14 a is disposed. Is located in

Further, the two reflecting portions 13 are provided between the light emitting element 11 and the wall 14 and in positions close to the wall 14 and separated from each other across the light emitting element 11.
The two reflecting portions 13 are provided so as to be inclined so as to reflect the light emitted from the light emitting element 11 toward the center of the smoke detection portion 10.

  The light emitted from the light emitting element 11 is reflected by the reflecting portion 13 (1) and reflected by the first light path LP 1 toward the center of the smoke detecting portion 10 and by the reflecting portion 13 (2) to the center of the smoke detecting portion 10 Through the two light paths of the second light path LP2. That is, the reflecting portions 13 (1) and 13 (2) disposed between the light emitting element 11 and the wall 14 reflect the light from the light emitting element 11 toward the smoke detection space (the center of the smoke detecting portion 10) Play a role.

  On the other hand, the light receiving element 12 is provided, for example, on the back side of the light emitting element 11 and at a position where the central axis in the plane direction of the light emitting element 11 and the central axis 12 a in the plane direction of the light receiving element 12 are orthogonal. It is arranged to be directed to the center of the smoke section 10. That is, the light receiving element 12 is provided at a position where the light emitted from the light emitting element 11 is not directly incident. By such an arrangement, a first scattering angle θ1 is formed between the first optical path LP1 and the optical axis 12a of the light receiving element 12, and between the second optical path LP2 and the optical axis 12a of the light receiving element 12. The second scattering angle θ2 is formed.

  In the first embodiment, a light emitting diode is used as the light emitting element 11, and a photodiode is used as the light receiving element 12.

  Each of the reflection part 13 (1) and the reflection part 13 (2) can switch between a reflection state in which the light emitted from the light emitting element 11 is reflected and a non reflection state in which the light emitted from the light emitting element 11 is not reflected Structure. The detailed configuration of the reflection unit 13 will be described later with reference to FIG.

  FIG. 2 is a block diagram of the smoke sensor 1 according to the first embodiment of the present invention. As shown in FIG. 2, the smoke sensor 1 according to the first embodiment includes a light emitting element 11, a light receiving element 12, a reflecting unit 13, a control unit 20, and a notification unit 30. In addition, the reflection part 13 is comprised by two reflection part 13 (1), 13 (2), and is controlled by the control part 20 separately. In addition, the control unit 20 switches and controls the reflecting units 13 (1) and 13 (2) individually, and also plays a role of a smoke determining unit that determines the smoke type based on the output signal from the light receiving element 12.

  Next, based on the block diagram of FIG. 2, the operation of the smoke detector in the first embodiment will be described. When it is desired to perform smoke sensing, the control unit 20 controls the light emitting element 11 to emit light. Then, the control unit 20 individually performs switching control of the reflection state and the non-reflection state of the reflection unit 13 (1) and the reflection unit 13 (2). Specifically, the control unit 20 performs switching control so that the reflection unit 13 (1) and the reflection unit 13 (2) do not simultaneously enter the reflection state.

  As a result, the first optical path LP1 and the second optical path LP2 are not simultaneously formed. Therefore, when the first light path LP1 is formed, the light receiving element 12 receives the amount of received scattered light obtained by scattering of the light of the first light path LP1 by the substance that has entered the smoke detection space. When the second light path LP2 can be received as the concentration, the light receiving amount of the scattered light obtained by the light of the second light path LP2 being scattered by the substance that has entered the smoke detection space is taken as the second smoke density It can receive light.

  That is, the control unit 20 can alternately acquire the first smoke concentration and the second smoke concentration by alternately and repeatedly performing the switching control of the reflection unit 13 (1) and the reflection unit 13 (2). Then, the control unit 20 can calculate the ratio between the first smoke concentration value and the second smoke concentration value, and can determine the type of smoke according to the calculated ratio.

  Specifically, the ratio of the value of the first smoke concentration obtained with the scattering angle θ1 to the value of the second smoke concentration obtained with the scattering angle θ2, and the type of smoke By verifying the relationship of in advance, the control unit 20 can determine the type of smoke according to the size of the calculated ratio.

  Next, a specific configuration of the reflection unit 13 will be described. FIG. 3 is a view showing a configuration example of the reflection unit 13 used in the smoke sensor in the first embodiment of the present invention. The two reflecting portions 13 (1) and 13 (2) shown in FIG. 1 have the same configuration, and in FIG.

  The reflection unit 13 includes a mirror 13a for reflecting the light emitted from the light emitting element 11, and a liquid crystal shutter 13b installed on the side of the reflection surface which is the front surface of the mirror 13a. The liquid crystal shutter 13b can switch between a reflection state in which light from the outside is transmitted to the mirror 13a and a non-reflection state in which light from the outside is not transmitted to the mirror 13a by a control signal from the control unit 20. It is a structure.

  Therefore, the control unit 20 switches the reflection unit 13 (1) to the reflection state, and switches the reflection unit 13 (2) to the non-reflection state, so that the first smoke is received via the light receiving element 12. You can get the concentration value. Similarly, the control unit 20 switches the reflection unit 13 (1) to the non-reflection state, and switches the reflection unit 13 (2) to the reflection state, so that the second light You can get the value of smoke concentration.

  Furthermore, the control unit 20 can determine the type of smoke according to the magnitude of the ratio calculated based on the value of the first smoke concentration and the value of the second smoke concentration. The control unit 20 can repeatedly perform switching control of the reflection units 13 (1) and 13 (2) to repeatedly acquire the first smoke density value and the second smoke density value. In such a case, the control unit 20 can calculate the ratio based on a plurality of times of acquired data, and can stabilize the detection accuracy.

  Moreover, it is possible to set an appropriate value appropriately according to the installation environment or the type of smoke to be identified, as the period of the reflection state and the non-reflection state, and the number of repetitions.

  Furthermore, when smoke is detected, the control unit 20 can notify the outside through the notification unit 30 together with the type information.

  As described above, according to Embodiment 1, the light from the light emitting element can be reflected with the light emitting element directed outward, and the light can be irradiated to the smoke detection space, so the smoke sensor can be miniaturized. In addition, it is possible to obtain a smoke detector capable of detecting smoke with high accuracy.

  In addition, by providing a pair of reflecting portions capable of switching control between the reflecting state and the non-reflecting state, it is possible to obtain two types of smoke density values having different scattering angles after making one light emitting element. . As a result, the smoke type can be determined, and stable and highly accurate smoke detection processing using one light source can be realized.

  Although not shown in FIG. 1, it is also conceivable to dispose a stray light prevention block at an appropriate position in the smoke detection portion for preventing light from a specific direction from entering the light receiving element. By using such a stray light prevention block, it is possible to reduce noise light that affects the value of the smoke density. As a result, the identification accuracy and the detection accuracy of smoke can be further stabilized and enhanced.

  Further, in the first embodiment, the liquid crystal shutter 13 b is provided on the reflective surface side of the reflective portion 13, but it is sufficient that the light emitted from the light emitting element 11 is not physically transmitted. For example, instead of the liquid crystal shutter 13b, an open / close shutter for blocking light by plastic or the like may be provided on the reflective surface side of the reflection unit 13, and the open / close shutter may be mechanically opened and closed.

  DESCRIPTION OF SYMBOLS 1 smoke detector, 10 smoke detector, 11 light emitting element, 12 light receiving element, 12a optical axis, 13 reflector, 13a mirror, 13b liquid crystal shutter, 14 wall, 14a labyrinth member, 20 control unit (smoke determination unit), 30 report unit, LP1 first light path, LP2 second light path, θ1 first scattering angle, θ2 second scattering angle.

Claims (1)

A light emitting element that emits light;
A reflecting unit that reflects light from the light emitting element toward a smoke detection space;
A light receiving element that outputs a signal according to the amount of received scattered light obtained by scattering the light reflected by the reflecting portion by the substance that has entered the smoke detection space;
A smoke detector equipped with
The smoke detector, wherein the light emitting element emits light toward the outside of the smoke detection space.

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