smoke sensor

Abstract

To provide a smoke sensor capable of detecting a fire in which no smoke is generated, without using a sensor for heat detection.SOLUTION: In a smoke sensor comprising a light-emitting element which emits light toward a smoke detection section and a light-receiving element which receives the light of the light-emitting element scattered by an inflow substance flowing into the smoke detection section, provided are a first wall part, a second wall part, and a support member which directly or indirectly supports the second wall part. The first wall part is provided at a position where light from the light-emitting element is reflected and incident to the light-receiving element in a case where there is no second wall part. The second wall part is configured to reflect light from the light-emitting element in a direction other than toward the light-receiving element by blocking the space between the light-emitting element and the first wall part or absorb light from the light-emitting element by blocking the space between the light-emitting element and the first wall part. The second wall part or the support member is composed of a material which is at least partially deformed or molten by heat from a fire.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a scattered light smoke detector. [Background technology]

[0002] Conventionally, among fire detectors that detect the occurrence of a fire, smoke detectors that detect a fire by detecting smoke and heat detectors that detect a fire by detecting heat have been known. Furthermore, so-called combined fire detectors that have both smoke detection and heat detection functions have also been proposed (see, for example, Patent Document 1). The fire detector in Patent Document 1 has a light-emitting element and a light-receiving element for detecting smoke, and a heat detection sensor for detecting heat. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-190306 Summary of the Invention [Problem to be solved by the invention]

[0004] The fire detector of Patent Document 1 is equipped with a heat detection sensor, so it can detect fires even in the case of fires that do not generate smoke. However, a combined fire detector like the one in Patent Document 1 requires a thermistor, which is a sensor for detecting heat, in addition to a photodiode, which is a sensor for detecting smoke. For this reason, combined fire detectors equipped with multiple sensors have the problem of increased manufacturing costs compared to fire detectors that detect only smoke or heat, such as smoke detectors or heat detectors.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a smoke detector that can detect fires that do not produce smoke without using a heat detection sensor. [Means for solving the problem]

[0006] The smoke detector disclosed herein is a smoke detector having a light-emitting element that emits light toward a smoke detection section and a light-receiving element that receives light from the light-emitting element scattered by inflow material into the smoke detection section, and is provided with a first wall portion, a second wall portion, and a support member that directly or indirectly supports the second wall portion, wherein the first wall portion is positioned so that, when the second wall portion is not present, light from the light-emitting element is reflected and made incident on the light-receiving element, and the second wall portion blocks the space between the light-emitting element and the first wall portion, thereby reflecting light from the light-emitting element in a direction other than the light-receiving element, or blocks the space between the light-emitting element and the first wall portion, thereby absorbing light from the light-emitting element, and the second wall portion or the support member is made of a material that is at least partially deformed or melted by heat from a fire. Another smoke detector disclosed herein is a smoke detector having a light-emitting element that emits light toward a smoke detection section and a light-receiving element that receives light from the light-emitting element scattered by inflow material into the smoke detection section, and is provided with a wall portion that is positioned to reflect light from the light-emitting element and make it incident on the light-receiving element, and is coated with paint that changes from a first color that transmits or absorbs light to a second color that reflects light due to heat from a fire. [Effects of the Invention]

[0007] According to the smoke detector of the present disclosure, heat from a fire causes light from the light-emitting element to be reflected by the wall and enter the light-receiving element. Therefore, even if no smoke is generated during a fire, light from the light-emitting element enters the light-receiving element, making it possible to detect the occurrence of a fire without using a heat detection sensor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of the smoke detector according to the first embodiment, disassembled into a cover body, an optical base cover, and a fixing part, as viewed from the cover body side. FIG. [Figure 2] 1 is an exploded view of a smoke detector according to a first embodiment. [Figure 3] 1 is a perspective view of the smoke detector according to the first embodiment, disassembled into a cover body, an optical base cover, and a fixing part, as viewed from the fixing part side. FIG. [Figure 4] 3 is a diagram illustrating a first wall portion and a second wall portion of the smoke sensor according to the first embodiment. FIG. [Figure 5] 3 is a diagram illustrating a first wall portion of the smoke sensor according to the first embodiment. FIG. [Figure 6] 4 is a diagram illustrating a second wall portion of the smoke sensor according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments and modifications of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments and modifications, and various modifications are possible without departing from the spirit of the present disclosure. Furthermore, the present disclosure includes all possible combinations of the configurations shown in the following embodiments and modifications. Furthermore, in the following description, terms indicating directions (e.g., "up," "down," "right," "left," "front," "rear," etc.) will be used as appropriate to facilitate understanding, but these are for explanatory purposes only and do not limit the present disclosure.

[0010] Furthermore, the devices shown in the drawings are examples of the devices of the present disclosure, and the devices of the present disclosure are not limited to the devices shown in the drawings. Furthermore, in each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is common throughout the entire specification.

[0011] Embodiment 1 (smoke detector) 1 is a perspective view of a smoke detector 100 according to embodiment 1, disassembled into a cover body 10, an optical base cover 20, and a fixing portion 2, as viewed from the cover body 10 side. The smoke detector 100 comprises the cover body 10, a plurality of support posts 11, a protective plate 12, the optical base cover 20, an optical base 30, a substrate 40, a rear cover 50, and a mounting bracket 51. The cover body 10, the plurality of support posts 11, the protective plate 12, and the optical base cover 20 constitute the cover portion 1 of the smoke detector 100.

[0012] The cover body 10 has a substantially dome shape. A protective plate 12 is connected to the cover body 10 by a plurality of support columns 11. The support columns 11 are arranged with gaps SP in the circumferential direction. Each of the support columns 11 is, for example, a rib having a substantially triangular shape. The support columns 11 are made of a material that is easily deformed or melted by heat. For example, the support columns 11 are made of ABS resin or ACS resin.

[0013] The optical bench cover 20 has a cylindrical shape with the side facing the cover body 10 closed by a substantially circular flat plate 20a. The optical bench cover 20 is housed inside the cover body 10. More specifically, the optical bench cover 20 is contained in the space surrounded by the protective plate 12, the support posts 11, and the cover body 10, and is held between the protective plate 12 and the fixed part 2. The optical bench 30 is housed inside the optical bench cover 20. The optical bench cover 20 is made of a material that is easily deformed or melted by heat. For example, the optical bench cover 20 is made of ABS resin or ACS resin.

[0014] The fixed part 2 is composed of an optical bench 30, a substrate 40, and a back cover 50. The substrate 40 is fixed to the back cover 50. The fixing method is not particularly limited as long as the substrate 40 is fixed to the back cover 50. A mounting bracket 51 is attached to the surface of the back cover 50 opposite the surface to which the substrate 40 is fixed. The fixed part 2 is attached to a receiver (not shown) provided on the installation surface by the mounting bracket 51. The installation surface of the smoke detector 100 is a ceiling, a wall, etc. The diameter of the back cover 50 is shorter than the diameter of the cover body 10. The back cover 50 is housed inside the cover body 10. Therefore, the cover part 1 covers the fixed part 2, and the cover part 1 protects the fixed part 2. The configuration in which the cover part 1 and the fixed part 2 are combined will be described later.

[0015] The optical bench 30 is fixed to the substrate 40. There are no particular limitations on the fixing method as long as the optical bench 30 is fixed to the substrate 40. The optical bench 30 is a substantially cylindrical member. The optical bench 30 is covered by the optical bench cover 20 to prevent external light from entering. The optical bench cover 20 is housed in a space surrounded by the protective plate 12, the support posts 11, and the cover body 10, and is pressed from the outside by the protective plate 12 toward the rear cover 50. In other words, the optical bench cover 20 is directly supported by the support posts 11 and the protective plate 12. Therefore, the optical bench cover 20 and the optical bench 30 do not need to be fixed with screws or the like.

[0016] Fig. 2 is an exploded view of smoke detector 100 according to embodiment 1. Fig. 2 shows smoke detector 100 attached to a horizontal ceiling, disassembled and viewed from diagonally below, with mounting bracket 51 shown at the top and cover body 10 shown at the bottom.

[0017] A light emitting element 31 and a light receiving element 32, which will be described later, are provided on the substrate 40 fixed to the rear cover 50. The light emitting element 31 and the light receiving element 32 are provided on the surface of the substrate 40 opposite the surface that contacts the rear cover 50. The light emitting element 31 and the light receiving element 32 extend through the optical bench 30 fixed to the substrate 40 toward the optical bench cover 20.

[0018] The light-emitting element 31 is, for example, an LED. The light-emitting element 31 emits light at a predetermined timing toward the smoke detection unit 34 located inside the optical bench 30. The light-receiving element 32 is, for example, a photodiode. When smoke or other inflowing matter enters the smoke detection unit 34 of the optical bench 30, the light-receiving element 32 detects scattered light that is generated when light emitted from the light-emitting element 31 is reflected by particles of the inflowing matter. In other words, the smoke detector 100 is a photoelectric spot-type detector. The smoke detection unit 34 will be described later.

[0019] A labyrinth wall 36 is provided on the inside of the cylindrical peripheral wall 35 of the optical bench 30. Furthermore, a first wall portion 61 is provided on the inside of the cylindrical peripheral wall 35 of the optical bench 30. The labyrinth wall 36 and the first wall portion 61 are provided on the base plate 30a of the optical bench 30. The labyrinth wall 36 and the first wall portion 61 extend from the base plate 30a of the optical bench 30 towards the optical bench cover 20. The first wall portion 61 may contact the flat plate 20a of the optical bench cover 20. Further details regarding the first wall portion 61 will be described later.

[0020] FIG. 3 is a perspective view of the smoke detector 100 according to the first embodiment, disassembled into the cover body 10, the optical bench cover 20, and the fixed portion 2, as viewed from the fixed portion 2 side. As shown in FIG. 3, a second wall portion 62 is provided on the inside of the cylindrical outer periphery of the optical bench cover 20. That is, the second wall portion 62 is directly supported by the optical bench cover 20. The second wall portion 62 is provided on the surface of the flat plate 20a of the optical bench cover 20 facing the optical bench 30. The second wall portion 62 extends from the flat plate 20a of the optical bench cover 20 toward the fixed portion 2. The second wall portion 62 may contact the base plate 30a of the optical bench 30 (see FIG. 2). Other details regarding the second wall portion 62 will be described later.

[0021] FIG. 4 is a diagram illustrating the first wall portion 61 and the second wall portion 62 of the smoke detector 100 according to the first embodiment. (a) of FIG. 4 is a side view of the smoke detector 100. (b) of FIG. 4 is a cross-sectional view taken along line AA in (a) of FIG. 4. As shown in (a) of FIG. 4, when the smoke detector 100 is viewed from the side, the fixing portion 2 is covered by the cover portion 1, and therefore only a portion of the mounting bracket 51 attached to the rear cover 50 is visible. The optical base cover 20 can be seen through the gaps SP between the multiple supports 11 of the cover body 10.

[0022] As shown in Figure 4(b), the area around the intersection of a first imaginary line L1 extending perpendicularly from the light-emitting element 31 and a second imaginary line L2 extending perpendicularly from the light-receiving element 32 is referred to as the smoke detection unit 34. The smoke detection unit 34 is located closer to the center of the optical bench 30 than a plurality of labyrinth walls 36 provided inside the peripheral wall 35 of the optical bench 30. The light-emitting element 31 emits light toward the smoke detection unit 34 located closer to the center of the optical bench 30. The light-receiving element 32 receives light from the light-emitting element 31 that has been scattered by inflowing matter, such as smoke, into the smoke detection unit 34.

[0023] As shown in FIG. 4(b), when the cover unit 1 and the fixing unit 2 are combined, the second wall unit 62 is located between the light-emitting element 31 and the first wall unit 61. The surface of the second wall unit 62 is formed of a color that reflects light. For example, the surface of the second wall unit 62 is white. Therefore, light emitted from the light-emitting element 31 toward the smoke detection unit 34 is reflected by the second wall unit 62. The light reflected by the second wall unit 62 is absorbed by the peripheral wall 35 and the labyrinth wall 36 of the optical bench 30. Therefore, in the steady state, the light emitted from the light-emitting element 31 does not enter the first wall unit 61. Alternatively, the surface of the second wall unit 62 may be formed of a color that absorbs light. For example, the surface of the second wall unit 62 is black. In this case, the light emitted from the light-emitting element 31 toward the smoke detection unit 34 is absorbed by the second wall unit 62. Therefore, in the steady state, the light emitted from the light-emitting element 31 does not enter the first wall unit 61.

[0024] The second wall 62 is made of a material that is easily deformed or melted by heat. For example, the second wall 62 is made of ABS resin or ACS resin. The first wall 61 may be made of a material different from that of the second wall 62 so that the heat-resistant temperature of the first wall 61 is higher than that of the second wall 62. For example, the first wall 61 may be made of polycarbonate.

[0025] Figure 5 is a diagram illustrating the first wall portion 61 of the smoke sensor 100 according to embodiment 1. Figure 5(a) is a side view of the fixed portion 2. Figure 5(b) is a side view of the fixed portion 2 as viewed in the direction of the arrow in Figure 5(a). As can be seen by comparing Figure 4(a) with Figure 5(a), when the smoke sensor 100 is viewed from the side, most of the fixed portion 2 is not visible because it is covered by the cover portion 1.

[0026] The first wall 61 is provided perpendicular to the base plate 30a of the optical bench 30, and reflects light from the light-emitting element 31 to make it incident on the light-receiving element 32. The first wall 61 is provided at a position where the light emitted from the light-emitting element 31 is incident. In other words, the first wall 61 is installed within an illumination angle range centered on the optical axis of the light-emitting element 31. The light-receiving element 32 is provided at a position where the light reflected by the first wall 61 from the light-emitting element 31 is incident.

[0027] In FIG. 5B, arrows conceptually indicate light emitted from the light-emitting element 31 and incident on the first wall 61 as first incident light 71, and light reflected by the first wall 61 and incident on the light-receiving element 32 as first reflected light 81. The first incident light 71 represents light within the illumination angle of the light-emitting element 31. A line perpendicular to the surface of the first wall 61 is indicated as a third virtual line L3, the angle at which the light from the light-emitting element 31 is incident on the first wall 61 is indicated as angle θ1, and the angle at which the light from the light-emitting element 31 is reflected by the first wall 61 is indicated as angle φ1. It is sufficient for the first wall 61 to reflect the light from the light-emitting element 31 so that it is incident on the light-receiving element 32. Therefore, the angle θ1 is not particularly limited. For example, the angle θ1 at which the light from the light-emitting element 31 is incident on the first wall 61 is 33°. In this case, according to the law of light reflection, the angle φ1 at which the light from the light emitting element 31 is reflected by the first wall portion 61 is also 33°.

[0028] Figure 6 is a diagram illustrating the second wall portion 62 of the smoke sensor 100 according to embodiment 1. Figure 6(a) is a diagram illustrating the cover portion 1 as viewed from the side. Figure 6(b) is a diagram illustrating the cover portion 1 as viewed in the direction of the arrow in Figure 6(a).

[0029] In (b) of Figure 6, when the optical bench cover 20 is combined with the optical bench 30, the area where the light-emitting element 31 is located is shown as light-emitting element area 31a, and the area where the light-receiving element 32 is located is shown as light-receiving element area 32a. Light emitted from the light-emitting element 31 is illustrated as being emitted from the light-emitting element area 31a. In (b) of Figure 6, light emitted from the light-emitting element 31 and incident on the second wall portion 62 is conceptually shown by arrows as second incident light 72, and light reflected by the second wall portion 62 is conceptually shown as second reflected light 82. The second incident light 72 represents light within the illumination angle of the light-emitting element 31.

[0030] The second wall 62 is provided at a position where the light emitted from the light-emitting element 31 is incident. That is, the second wall 62 is provided within a range of an illumination angle centered on the optical axis of the light-emitting element 31. The light-receiving element 32 is provided at a position where the light reflected from the light-emitting element 31 by the second wall 62 does not enter. That is, the light-receiving element 32 is provided outside the range of an illumination angle centered on the optical axis of the light reflected from the second wall 62.

[0031] 6(b), a line perpendicular to the wall surface of the second wall portion 62 is represented by a fourth virtual line L4, the angle at which light from the light-emitting element 31 is incident on the second wall portion 62 is represented by angle θ2, and the angle at which the light from the light-emitting element 31 is reflected by the second wall portion 62 is represented by angle φ2. The second wall portion 62 only needs to be provided at a position that prevents the light from the light-emitting element 31 from being incident on the first wall portion 61, and the angle θ2 is not particularly limited. For example, the angle θ2 at which the light from the light-emitting element 31 is incident on the second wall portion 62 is 30°. In this case, according to the law of light reflection, the angle φ2 at which the light from the light-emitting element 31 is reflected by the second wall portion 62 is also 30°.

[0032] (Smoke detection processing) The smoke detection process by the smoke detector 100 will now be described. During steady-state operation, clean air that does not contain smoke flows into the smoke detection unit 34 of the smoke detector 100 as an inflow. For this reason, light from the light-emitting element 31 is not scattered in the smoke detection unit 34, and if the second wall portion 62 has a light-reflecting color, the light from the light-emitting element 31 is reflected by the second wall portion 62 and absorbed by the peripheral wall 35 and the labyrinth wall 36. Furthermore, if the second wall portion 62 has a light-absorbing color, the light from the light-emitting element 31 is absorbed by the second wall portion 62. In other words, during steady-state operation, the light from the light-emitting element 31 does not enter the first wall portion 61, and the light-receiving element 32 does not receive the light from the light-emitting element 31.

[0033] When smoke is generated during a fire, the smoke flows into the smoke detection unit 34 as an inflow. The light from the light-emitting element 31 becomes scattered light due to the smoke that has flowed into the smoke detection unit 34. The light-receiving element 32 receives this scattered light. The smoke detector 100 detects a fire when the light-receiving element 32 receives the scattered light.

[0034] However, there are cases where no smoke is generated even when a fire breaks out. In this embodiment, the second wall 62 is made of a material that is easily deformed or melted by heat. Therefore, a portion of the second wall 62, which separates the light-emitting element 31 from the first wall 61, is deformed or melted by the heat of the fire, and light from the light-emitting element 31 is incident on the first wall 61. Then, the light-receiving element 32 receives the light of the light-emitting element 31 reflected by the first wall 61. As a result, the smoke detector 100 can detect a fire.

[0035] Furthermore, even if smoke is generated during a fire, if the smoke density is low, the amount of light received by the light-receiving element 32 may be small, and the smoke detector 100 may not determine that a fire has occurred. However, in this embodiment, a portion of the second wall 62 is deformed or melted by the heat of the fire, causing the light from the light-emitting element 31 to be incident on the first wall 61. As a result, the light-receiving element 32 receives the light reflected by the first wall 61. As a result, the amount of light received by the light-receiving element 32 increases, allowing the smoke detector 100 to determine that a fire has occurred.

[0036] Furthermore, if the heat resistance temperature of the first wall portion 61 is higher than that of the second wall portion 62, the second wall portion 62 will deform or melt due to the heat in the event of a fire before the first wall portion 61. Therefore, even if a part of the second wall portion 62 is deformed or melted due to the heat of the fire, the first wall portion 61 will be unaffected by the heat of the fire and will be able to maintain a shape that allows it to receive light from the light-emitting element 31. Therefore, the smoke detector 100 can more reliably detect a fire due to the heat of the fire.

[0037] The optical bench cover 20 is also made of a material that easily deforms or melts due to heat. Therefore, the optical bench cover 20, which directly supports the second wall portion 62, is partially or completely deformed or melted by the heat of a fire. When the optical bench cover 20 deforms or melts, the position and installation angle of the second wall portion 62 provided on the optical bench cover 20 are shifted. When the position and installation angle of the second wall portion 62 are shifted, the light from the light-emitting element 31 is not reflected by the second wall portion 62, but is instead incident on the first wall portion 61. As a result, the light-receiving element 32 receives the light reflected by the first wall portion 61 from the light-emitting element 31. As a result, the smoke detector 100 can detect a fire.

[0038] In addition to the above, there is also a configuration in which the support 11 is made of a material that easily deforms or melts due to heat. The optical bench cover 20 is housed in a space surrounded by the protective plate 12, the support 11, and the cover body 10. Furthermore, the optical bench cover 20 and the optical bench 30 are not fixed together; instead, the optical bench cover 20 is pressed against the fixed portion 2 by the protective plate 12, thereby covering the optical bench 30. Due to this configuration, if the support 11 is partially or completely deformed or melted by the heat of a fire, the protective plate 12 will no longer be able to support the optical bench cover 20, causing the optical bench cover 20 to fall or the position of the optical bench cover 20 supported by the protective plate 12 to shift. Because the second wall portion 62 is provided on the optical bench cover 20, if the optical bench cover 20 falls, the second wall portion 62 will disappear. Furthermore, if the position of the optical bench cover 20 shifts, the position and installation angle of the second wall portion 62 provided on the optical bench cover 20 will also shift. That is, if the support 11 that indirectly supports the second wall portion 62 is deformed or melted, the second wall portion 62 may disappear or the position or installation angle of the second wall portion 62 may shift, causing the light from the light-emitting element 31 to be incident on the first wall portion 61 without being reflected by the second wall portion 62. In this case, the light-receiving element 32 receives the light of the light-emitting element 31 reflected by the first wall portion 61. As a result, the smoke detector 100 can detect a fire.

[0039] Note that external light may enter the optical bench 30 if the optical bench cover 20 becomes detached or shifted. In this case, the amount of light received by the light receiving element 32 steadily increases. However, the increase in the amount of light received due to external light is filtered out as noise by a capacitor provided in the processing circuit that processes the output signal from the light receiving element 32. For this reason, the smoke detector 100 does not determine that there is a fire just because the amount of light received by the light receiving element 32 increases due to external light.

[0040] In the smoke detector 100, it is only necessary that the following relationship be satisfied: in normal operation, light from the light-emitting element 31 is absorbed by the second wall portion 62 and / or the peripheral wall 35, and in the event of a fire, at least a portion of the second wall portion 62 is missing and / or moved, causing the light from the light-emitting element 31 to be reflected by the first wall portion 61 toward the light-receiving element 32. The installation positions and installation angles of the light-emitting element 31, the light-receiving element 32, the first wall portion 61, and the second wall portion 62 are not particularly limited.

[0041] As described above, the smoke detector 100 of this embodiment has a light-emitting element 31 that emits light toward the smoke detection section 34 and a light-receiving element 32 that receives the light from the light-emitting element 31 scattered by the inflow of matter that has entered the smoke detection section 34, and is provided with a first wall portion 61, a second wall portion 62, and a support member that directly or indirectly supports the second wall portion 62, and the first wall portion 61 is positioned so that, when the second wall portion 62 is not present, the light from the light-emitting element 31 is reflected and made incident on the light-receiving element 32, and the second wall portion 62 blocks the gap between the light-emitting element 31 and the first wall portion 61, thereby reflecting the light from the light-emitting element 31 in a direction other than the light-receiving element 32, or blocks the gap between the light-emitting element 31 and the first wall portion 61, thereby absorbing the light from the light-emitting element 31, and the second wall portion 62 or the support member is made of a material that is at least partially deformed or melted by the heat of a fire.

[0042] In this configuration, the support member that directly supports the second wall portion 62 is the optical bench cover 20, and the support members that indirectly support the second wall portion 62 are the support posts 11 and the protective plate 12. The second wall portion 62, the optical bench cover 20 that directly supports the second wall portion 62, or the support posts 11 that indirectly support the second wall portion 62 are at least partially deformed or melted by heat caused by a fire. As a result, light from the light-emitting element 31 is reflected by the first wall portion 61 and enters the light-receiving element 32. Therefore, even if no smoke is generated during a fire, the light from the light-emitting element 31 enters the light-receiving element 32, allowing the smoke detector 100 to detect a fire.

[0043] Furthermore, in smoke detector 100 according to this embodiment, first wall 61 has a higher heat resistance temperature than second wall 62. Even if part of second wall 62 is deformed or melted by the heat of a fire, first wall 61 can maintain a shape that allows it to receive light from light-emitting element 31, allowing smoke detector 100 to more reliably detect fires.

[0044] Embodiment 2 In the first embodiment, a smoke detector 100 was described that includes a first wall portion 61 and a second wall portion 62. In the present embodiment, a smoke detector will be described that does not include a second wall portion 62 and that includes a single reflecting wall on the optical bench 30. The following description will focus on the differences from the first embodiment.

[0045] The smoke detector of this embodiment has a wall portion coated with color-changing paint in the same position as first wall portion 61 of embodiment 1. However, unlike embodiment 1, it does not have second wall portion 62. Therefore, even in a steady state, light emitted from light-emitting element 31 is incident on the wall portion.

[0046] The wall changes from a light-transmitting or light-absorbing color to a light-reflecting color due to heat. In a steady state, the color of the wall is a light-transmitting or light-absorbing color. Therefore, in a steady state, light from the light-emitting element 31 is transmitted through the wall or absorbed by the wall, and the light-receiving element 32 does not receive the light reflected from the light-emitting element 31. However, if a fire breaks out, the heat of the fire changes the color of the wall to a light-reflecting color. Therefore, the light from the light-emitting element 31 is reflected by the wall, and the light-receiving element 32 receives the light reflected from the light-emitting element 31. As a result, the smoke detector can detect a fire. The wall is coated with, for example, a paint that changes from a light-absorbing black color to a light-reflecting white color as the ambient temperature rises.

[0047] As described above, the smoke detector of this embodiment is a smoke detector having a light-emitting element 31 that emits light toward the smoke detection section 34 and a light-receiving element 32 that receives light from the light-emitting element 31 scattered by the inflow of matter that has flowed into the smoke detection section 34, and is provided with a wall portion that is positioned to reflect light from the light-emitting element 31 and make it incident on the light-receiving element 32, and is coated with paint that changes from a first color that transmits or absorbs light to a second color that reflects light due to the heat of a fire.

[0048] Even when the smoke detector is configured in this manner, the heat from a fire causes the wall to change color to one that reflects light, causing the light from the light-emitting element 31 to be reflected by the wall and enter the light-receiving element 32. Therefore, even when no smoke is generated in a fire, the light from the light-emitting element 31 enters the light-receiving element 32, allowing the smoke detector to detect a fire. Therefore, the same effect as in the first embodiment can be obtained.

[0049] <Modification> In another embodiment, the entire or a portion of the smoke detection unit 34, including the labyrinth wall 36, is coated with paint that changes from a first color, which is light-transmitting or light-absorbing, to a second color, which is light-reflecting, due to heat caused by a fire. This modification, unlike the second embodiment, does not include the first wall 61 and the second wall 62. Under normal conditions, the smoke detection unit 34, including the labyrinth wall 36, or a portion thereof, is a light-transmitting or light-absorbing color. When a fire breaks out, the entire or a portion of the smoke detection unit 34, including the labyrinth wall 36, changes to a second color, which is light-reflective, due to the heat of the fire. This configuration does not include the first wall 61 and the second wall 62. Therefore, although light from the light-emitting element 31 does not directly enter the light-receiving element 32, the amount of light from the light-emitting element 31 that reflects off the entire or a portion of the smoke detection unit 34, including the labyrinth wall 36, and then enters the light-receiving element 32 increases, thereby achieving the same effect as the first or second embodiment, in that an alarm can be triggered even in cases where no smoke is generated. [Explanation of symbols]

[0050] 1 Cover portion, 2 Fixing portion, 10 Cover body, 11 Support, 12 Protective plate, 20 Optical base cover, 20a Flat plate, 30 Optical base, 30a Base plate, 31 Light emitting element, 31a Light emitting element area, 32 Light receiving element, 32a Light receiving element area, 34 Smoke detection portion, 35 Surrounding wall, 36 Labyrinth wall, 40 Board, 50 Back cover, 51 Mounting bracket, 61 First wall portion, 62 Second wall portion, 71 First incident light, 72 Second incident light, 81 First reflected light, 82 Second reflected light, 100 Smoke detector, L1 First virtual line, L2 Second virtual line, L3 Third virtual line, L4 Fourth virtual line, SP Gap, θ1 Angle, θ2 Angle, φ1 Angle, φ2 Angle.

Claims

1. a light emitting element that emits light toward the smoke detecting unit; a light-receiving element that receives light from the light-emitting element scattered by an inflow of matter that has flowed into the smoke detecting section, A first wall portion; A second wall portion; a support member that directly or indirectly supports the second wall portion, the first wall portion is provided at a position where, in the absence of the second wall portion, the light from the light-emitting element is reflected and made incident on the light-receiving element; the second wall portion blocks the gap between the light-emitting element and the first wall portion to reflect the light from the light-emitting element in a direction other than the light-receiving element, or blocks the gap between the light-emitting element and the first wall portion to absorb the light from the light-emitting element, The second wall portion or the support member is made of a material that is at least partially deformed or melted by heat caused by a fire. Smoke detector.

2. The heat-resistant temperature of the first wall portion is higher than the heat-resistant temperature of the second wall portion.

10. The smoke detector of claim 1.

3. a light emitting element that emits light toward the smoke detecting unit; a light-receiving element that receives light from the light-emitting element scattered by an inflow of matter that has flowed into the smoke detecting section, A wall portion is provided. the wall portion is provided at a position where the light from the light-emitting element is reflected and made incident on the light-receiving element, The wall portion is coated with a paint that changes from a first color that transmits or absorbs light to a second color that reflects light due to heat from a fire. Smoke detector.

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