Smoke sensor

Abstract

To provide a smoke detector which is less likely to obstruct a flow of outside air within a smoke detecting chamber, which is easily obstructed due to a light-shielding wall protruding between a light-emitting unit and a light-receiving unit within the smoke detecting chamber.SOLUTION: A smoke detector comprises: a smoke detecting chamber 111 provided with a light-emitting element and a light-receiving element 1, and a light-shielding wall 114 between the light-emitting element and the light receiving element, for detecting smoke that has flowed thereinto; a smoke introducing unit which communicates with the smoke detecting chamber and into which outside air A is introduced from outside; and an opening 121 communicating between the smoke introducing unit and the smoke detecting chamber. While the outside air rotates, the outside air is introduced from the smoke introducing unit into the smoke detecting chamber through the opening and a center of rotation is positioned horizontally away from the light-shielding wall.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a photoelectric smoke detector that optically detects smoke. [Background technology]

[0002] In the past, if a smoke detector was installed near a source of steam, such as near the bathroom door of a hotel room or a private room with a bathroom, the steam that entered the room could reach the smoke detection chamber, potentially resulting in a false fire alarm. Also, if a smoke detector was installed in a dusty warehouse or similar location, the dust that entered the room could reach the smoke detection chamber, potentially resulting in a false fire alarm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-67067 [Patent Document 2] Japanese Patent Publication No. 2020-135780 Summary of the Invention [Problem to be solved by the invention]

[0004] As a smoke detector capable of detecting such false fire alarms, Patent Document 1 describes a smoke detector with a two-stage light-blocking structure in which the smoke detection chamber and smoke inlet are separated into upper and lower sections. The smoke detector in Patent Document 1 prevents false detections due to steam and dust contained in the invading outside air by extending the smoke detection path vertically, thereby reducing false fire alarms. Meanwhile, when installing a smoke detector in a space with limited space, such as a hotel guest room or living room, or in a warehouse with a low ceiling, it is desirable to design the detector thin so that it protrudes minimally into the room or warehouse. However, the smoke detector in Patent Document 1 is difficult to thin because it is designed to suppress false detections by extending the smoke detection path vertically as described above. Therefore, Patent Document 2 provides a protruding ridge toward the smoke detection chamber, thereby reducing the thickness of the smoke detector and suppressing false smoke detections.

[0005] Fig. 1 shows an exploded perspective view of a conventional smoke detector 5 with a hill-shaped portion. When the smoke detector 5 is installed on the ceiling, the structure is disclosed in which an optical base 51, an optical base cover 52, and a smoke intake cover 53 are positioned and assembled in this order from top to bottom to take in outside air and detect smoke.

[0006] 2 and 3, in such a conventional smoke detector 5, outside air A entering between multiple labyrinth plates 532 rotates in a spiral along slope 531b of hill-shaped portion 531, rises up the slope of hill-shaped portion 531, and reaches the inside of smoke detection chamber 511 while being separated from steam, dust, etc. However, inside smoke detection chamber 511, light-shielding wall 514 is provided protruding inward to prevent light-receiving element 513 from directly receiving and detecting light from light-emitting element 512, and this obstructs the flow of outside air A swirling in the direction of the arrow.

[0007] 3, outside air A swirls and rises in a spiral along slope 531b of hill-like portion 531, passing through opening 521 and reaching smoke detection chamber 511. Therefore, smoke from a fire does not disappear due to this long smoke path. On the other hand, steam and dust are heavier than smoke and so disappear or fall before reaching smoke detection chamber 511, thereby suppressing false detections due to steam and dust.

[0008] The present invention aims to provide a smoke detector in which the flow of outside air in the smoke detection chamber is less likely to be obstructed by a light-shielding wall located between the light-emitting unit and the light-receiving unit, and outside air can easily reach the smoke detection chamber. [Means for solving the problem]

[0009] A smoke detector according to one embodiment of the present invention is a smoke detector comprising: a smoke detection chamber for detecting smoke that has flowed into the chamber, the smoke detection chamber having a light-emitting section, a light-receiving section, and a light-shielding wall located between the light-emitting section and the light-receiving section; a smoke inlet section that communicates with the smoke detection chamber and through which outside air is introduced; and an opening that communicates the smoke inlet section with the smoke detection chamber. The smoke introduction section is provided with a plurality of bent labyrinth plates and a hill-like portion protruding toward the opening inside the plurality of labyrinth plates, the height of the hill-like portion is the same as or approximately the same as the height of the labyrinth plates, and the top of the hill-like portion is eccentric in a direction away from the light-shielding wall in the horizontal direction when viewed from the center of the smoke detection chamber. The outside air is introduced from the smoke introduction section to the smoke detection chamber through the opening while rotating, and the center of rotation is , from the center of the smoke detectorIn a direction away from the light-shielding wall in the horizontal direction Eccentric It is characterized by being located In addition, one embodiment of the present invention provides a smoke detector comprising: a smoke detection chamber for detecting smoke that has flowed into the chamber, the smoke detection chamber having a light-emitting unit, a light-receiving unit, and a light-shielding wall located between the light-emitting unit and the light-receiving unit; a smoke inlet section that communicates with the smoke detection chamber and through which outside air is introduced; and an opening that connects the smoke inlet section to the smoke detection chamber, wherein the smoke inlet section is provided with a plurality of curved labyrinth plates and a hill-shaped section that protrudes toward the opening, the tops of the hill-shaped sections are eccentric in a direction away from the light-shielding wall in the horizontal direction, and the bottoms of the hill-shaped sections are not eccentric from the tops, the outside air is introduced from the smoke inlet section into the smoke detection chamber by passing through the opening while rotating, the center of the rotation being located in a direction away from the light-shielding wall, and the labyrinth plate located on the side farther from the light-shielding wall is smaller than the labyrinth plate located on the side closer to the light-shielding wall. [Effects of the Invention]

[0010] According to the present invention, it is possible to realize a smoke detector in which the flow of outside air in the smoke detection chamber is less likely to be obstructed by a light-shielding wall located between the light-emitting unit and the light-receiving unit, making it easier for outside air to reach the smoke detection chamber. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an exploded perspective view of a conventional smoke detector. [Figure 2] FIG. 2 is a bottom view of an optical bench in a conventional smoke detector. [Figure 3] FIG. 10 is a diagram showing the flow of outside air in a conventional smoke detector. [Figure 4] 1 is an exploded perspective view of a smoke detector according to a first embodiment of the present invention. [Figure 5] 1 is a cross-sectional view of a smoke detector according to a first embodiment of the present invention. [Figure 6] FIG. 2 is a bottom view of the optical bench according to the first embodiment of the present invention. [Figure 7] FIG. 2 is a bottom view of the optical bench and the optical bench cover according to the first embodiment of the present invention. [Figure 8] 1 shows a smoke introduction cover according to a first embodiment of the present invention. [Figure 9] 10 shows a smoke introduction cover according to a second embodiment of the present invention. [Figure 10] 10 shows a smoke introduction cover according to a third embodiment of the present invention. [Figure 11] FIG. 10 is a bottom view of an optical bench and an optical bench cover according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this application, the up and down directions are defined as the up and down directions when the smoke detector is installed on a horizontal ceiling. [Example]

[0013] FIG. 4 is an exploded perspective view of the smoke detector 1 in the first embodiment of the present invention. Components such as an insect screen are omitted. FIG. 4 is an exploded perspective view of the smoke detector 1 viewed from diagonally above. From above, the optical base 11, the optical base cover 12, and the smoke introduction cover 13 are shown. The smoke detector 1 is equipped with the optical base 11, the optical base cover 12, and the smoke introduction cover 13 shown in FIG. 4.

[0014] The optical bench cover 12 has an opening 121 near the center. The center of the smoke inlet cover 13 is raised to form a hill-shaped portion 131. The hill-shaped portion 131 protrudes toward the opening 121. The hill-shaped portion 131 is surrounded by a plurality of labyrinth plates 132 of the same shape and size. The plurality of labyrinth plates 132 are bent to form a labyrinth structure that blocks light from the sides.

[0015] 5 shows a cross section of smoke detector 1. Smoke detector 1 is a combination of optical base 11, optical base cover 12, and smoke inlet cover 13. Like conventional smoke detector 5, smoke detector 1 of Example 1 has a two-stage light-shielding structure in which smoke detection chamber 111 that detects smoke that has flowed into the interior and a smoke inlet section that introduces smoke are separated into upper and lower sections.

[0016] Outside air A is introduced into smoke detector 1 from the outside, as shown by the straight arrow in Fig. 5. When mounted on the ceiling as shown in Fig. 5, the area above optical bench cover 12 and surrounded by smoke detection wall 115 forms smoke detection chamber 111, and the portion from the underside of optical bench cover 12 to cover plate 133 of smoke inlet cover 13, through which outside air A is introduced from the outside, is the smoke inlet section.

[0017] Smoke detector 1 has a two-stage light-blocking structure in which smoke detection chamber 111, which detects smoke that has flowed into the interior, and a smoke inlet section, which introduces the smoke, are separated into upper and lower sections. The smoke inlet section communicates with smoke detection chamber 111 through opening 121. Each of multiple labyrinth plates 132 is bent in an L-shape. External light is blocked from smoke detection chamber 111 by multiple labyrinth plates 132 of smoke inlet cover 13 and cover plate 133 to which the multiple labyrinth plates 132 are attached.

[0018] As shown in FIGS. 5 and 6 , the optical bench 11 includes a smoke detection chamber 111 surrounded by a smoke detection wall 115. A light-shielding wall 114 is provided in a portion of the smoke detection chamber 111 to prevent the light-receiving element 113 from directly receiving and detecting light emitted from the light-emitting element 112. An opening 121 is provided below the smoke detection chamber 111 in the optical bench cover 12. A hill-shaped portion 131 of the smoke inlet cover 13 is provided below the opening 121. The top of the hill-shaped portion 131 is a flat apex 131a. In the first embodiment, the height of the hill-shaped portion 131, i.e., the height from the cover plate 133 to the apex 131a, is formed to be the same height as or approximately the same as the labyrinth plate 132, so as to be high enough to introduce outside air into the smoke detection chamber 111. The height of the hill-shaped portion in the embodiments described below is also formed in a similar manner. However, the height of the hill-shaped portion does not necessarily have to be approximately the same as the labyrinth plate.

[0019] Compared to the top 531a in the conventional smoke detector 5 shown in Figures 1 and 3, the top 131a in Example 1 is eccentric in a direction horizontally away from the light-shielding wall 114 in the smoke detection chamber 111, as shown by arrow B in Figure 5. The center position of the bottom surface 131c of the hill-shaped portion 131 is approximately the same as the center of the smoke detection chamber 111, which is inside the smoke detection wall 115 of the optical bench 11, as in the conventional smoke detector 5. Therefore, the left side of the slope 131b shown in Figure 5 is gentler than the right side, and the left and right inclination angles are asymmetric.

[0020] Outside air A introduced from outside is changed in direction so as to rotate as it passes between the multiple labyrinth plates 132. Then, as shown by the curved arrow in FIG. 5, the air rises while rotating along the slope 131b of the hill-shaped portion 131 and enters the smoke detection chamber 111. In the first embodiment, as shown by arrow B, the top 131a is eccentric in a direction that moves horizontally away from the light-shielding wall 114 of the smoke detection chamber 111. Therefore, since the rotating outside air A enters the smoke detection chamber 111 from the right side as shown in FIG. 5, the flow of the outside air A is not easily obstructed by the light-shielding wall 114 on the left side of the smoke detection chamber 111, and the outside air A can be smoothly introduced into the smoke detection chamber 111.

[0021] FIG. 6 shows a bottom view of the optical bench 11 of Example 1 shown in FIGS. 4 and 5. The smoke detection chamber 111 is surrounded by a substantially cylindrical smoke detection wall 115 of the optical bench 11. A light-emitting element 112, which is a light-emitting unit, is housed in a light-emitting element chamber 112a provided in the substantially cylindrical smoke detection wall 115, and a light-receiving element 113, which is a light-receiving unit, is housed in a light-receiving element chamber 113a. In the optical bench 11, the light-emitting element 112 and the light-receiving element 113 are provided inward around the periphery of the smoke detection chamber 111. In addition, a light-shielding wall 114 is provided between the light-emitting element 112 and the light-receiving element 113 in the smoke detection chamber 111. Furthermore, wall folds 115a, which are folds protruding diagonally, are provided on the inside of the smoke detection wall 115 at a position opposite the light-shielding wall 114.

[0022] Smoke detector 1 detects smoke by receiving scattered light emitted from light-emitting element 112 with light-receiving element 113. Light-shielding wall 114 is provided in a position where light-receiving element 113 does not directly detect light from light-emitting element 112. The inside of smoke detection chamber 111 is black so as to absorb light without reflecting it, but by providing wall folds 115a consisting of a plurality of protrusions on the wall surface extending from smoke detection wall 115 to the inside of smoke detection chamber 111, i.e., on the inner peripheral wall of smoke detection wall 115, reflection of light by smoke detection wall 115 is further reduced.

[0023] In Figure 6, the center line along which the light-shielding wall 114 extends is indicated by a dotted line. In Example 1, the smoke detection wall 115 is a wall portion that forms the outer periphery of the approximately circular smoke detection chamber 111. Portions of the light-emitting element chamber 112a and the light-receiving element chamber 113a protrude inward into the smoke detection chamber 111, but do not protrude inward where they intersect with the dotted line. The dotted line also indicates the diameter of the approximately circle that forms the smoke detection chamber 111, excluding the inward protrusion. The light-shielding wall 114 extends from the smoke detection wall 115 along the dotted line toward the center C of the smoke detection chamber 111.

[0024] In the first embodiment, the outside air A entering the smoke detection chamber 111 rotates clockwise in the bottom view of the optical bench 11, as shown by the arrow in FIG. 6 . The center of rotation of the outside air A depends on the position of the apex 131a of the hill-shaped portion 131, and is therefore eccentric in a direction horizontally away from the baffle wall 114, as shown by arrow B. As a result, the outside air A enters the smoke detection chamber 111 at a position where it is least likely to interfere with the baffle wall 114 while rotating, and the baffle wall 114 is less likely to obstruct the flow of the outside air A. Note that the inner side of the smoke detection wall 115 facing the light-emitting element 112, the light-receiving element 113, and the baffle wall 114 has wall folds 115a to suppress reflection of light from the light-emitting element 112. The apex of the wall folds 115a protrudes downstream of the flow of the outside air A, so that the approaching outside air A is less likely to obstruct the flow.

[0025] In Example 1, the direction in which the center of the outside air A is eccentric is the direction along the dotted line shown in Fig. 6, which is the direction in which the light-shielding wall 114 extends. The center of the outside air A is eccentric from the center C of the smoke detection chamber 111, which is the center of the dotted line, toward the direction in which the light-shielding wall 114 extends.

[0026] FIG. 7 shows a bottom view of the optical bench 11 and the optical bench cover 12 in Example 1. This is a view from below of the optical bench 11 with the optical bench cover 12 attached to the bottom of the optical bench 11. An opening 121 is provided in the optical bench cover 12. In FIG. 7, the smoke detection chamber 111 located above can be seen inside the opening 121. Inside the smoke detection chamber 111, the components of the optical bench 11, such as the light-shielding wall 114, can be seen. The optical bench 11 and the optical bench cover 12 in Example 1 are the same as the conventional optical bench 51 and the optical bench cover 52.

[0027] 7, the center line along which the light-shielding wall 114 extends is indicated by a dotted line. The opening 121 has a light-emitting element chamber 112a and a light-receiving element chamber 113a that protrude inward in a straight line, forming a protrusion 121a. However, the protrusions 121a provided in two locations do not overlap with the dotted line, and the opening 121 does not protrude inward at the location of the dotted line.

[0028] The dotted line in Fig. 7 also indicates the diameter of a circle that forms the periphery of opening 121, excluding protruding portion 121a. This circle is slightly smaller than the circle of smoke detection wall 115. This circle in Fig. 7 is centered at center C of the circle of smoke detection wall 115. Light-shielding wall 114 extends from smoke detection wall 115 along the dotted line toward center C of opening 121, and in Example 1, the direction in which the center of outside air A is eccentric is the direction along the dotted line, which is the direction in which light-shielding wall 114 extends.

[0029] In the first embodiment, the center C of the smoke detection chamber 111 and the opening 121 coincides with the centers of the optical bench 11, the optical bench cover 12, and the smoke introduction cover 13 when viewed from above or below.

[0030] Opening 121 is narrowed by protruding portion 121a in the direction closer to light-shielding wall 114, but as described above, outside air A rises toward top 131a of hill-like portion 131 and reaches smoke detection chamber 111, passing through opening 121 at a position shifted in the direction of arrow B. Therefore, protruding portion 121a does not hinder the introduction of outside air A into smoke detection chamber 111.

[0031] FIG. 8 shows the smoke inlet cover 13 in Example 1. FIG. 8(a) is a top view, and FIG. 8(b) is a side cross-sectional view. As shown in FIG. 8(a), the smoke inlet cover 13 has a plurality of labyrinth plates 132 formed thereon. A hill-shaped portion 131 is provided inside the plurality of labyrinth plates 132. FIG. 8(b) is a side cross-sectional view of the assembled smoke detector 1, in which the smoke inlet cover 13 is cut vertically along the dotted line and its extension shown in FIGS. 6 and 7. As shown in FIG. 8(b), the hill-shaped portion 131 and the plurality of labyrinth plates 132 are formed on a cover plate 133. The hill-shaped portion 131 has a disk-shaped top portion 131a, a disk-shaped bottom surface 131c that is larger than the top portion 131a, and a slope 131b that connects the periphery of the top portion 131a and the periphery of the bottom surface 131c. The bottom surface 131c is in contact with the cover plate 133, and the hill-like portion 131 and the cover plate 133 are integrally formed.

[0032] The labyrinth plates 132 are bent to block external light, but the inner ends of the labyrinth plates 132 in the smoke introduction cover 13 are directed away from the center of the smoke introduction cover 13. By arranging the ends of the labyrinth plates 132 in a direction that does not face the center, the outside air A that enters the inside of the smoke introduction section between the multiple labyrinth plates 132 hits the slope 131b of the hill-shaped portion 131 at an angle. Therefore, the outside air A inside the labyrinth plates 132 can be smoothly rotated along the slope 131b and reach the smoke detection chamber 111.

[0033] As shown in Figures 8(a) and 8(b), the center of the top 131a of the hill-shaped portion 131 of Example 1 is offset in the direction of arrow B from the center of the bottom 131c. The slope 131b that connects the periphery of the bottom 131c to the periphery of the top 131a varies in angle with the bottom 131c depending on the position. Due to the above-described configuration of the hill-shaped portion 131, outside air A rising along the slope 131b is introduced into the smoke detection chamber 111 at a position offset in the direction of arrow B. In Example 1, in the top view of the smoke introduction cover 13 shown in Figure 8(a), the outside air A rotates counterclockwise around the hill-shaped portion 131. In Figure 6, which is a bottom view of the optical bench 11, the outside air A rotates clockwise.

[0034] 6, due to the offset between the centers of top 131a and bottom 131c, the center of rotation of outside air A is offset in a direction horizontally away from light-shielding wall 114. Therefore, the flow of outside air A does not become significantly turbulent inside smoke detection chamber 111, and flows smoothly, enabling early detection of fires while suppressing false fire alarms. [Example]

[0035] The smoke detector 2 of Example 2 differs from the smoke detector 1 of Example 1 in the shape of the smoke inlet cover. FIG. 9 shows a smoke inlet cover 23 in Example 2. FIG. 9(a) is a top view of the smoke inlet cover 23, and FIG. 9(b) is a side cross-sectional view. The smoke detector 2 of Example 2 is a combination of an optical bench 21 (not shown), an optical bench cover 22 (not shown), and a smoke inlet cover 23, similar to Example 1. The optical bench 21 and the optical bench cover 22 of Example 2 are the same as the optical bench 11 and the optical bench cover 12 of Example 1 shown in FIGS. 4 to 7. The smoke inlet section, through which outside air A is introduced from the underside of the optical bench cover 22 to the cover plate 233 at the bottom of the smoke inlet cover 23 shown in FIG. 9(b), communicates with a smoke detection chamber 211 (not shown) through an opening 221 (not shown). As in Example 1, the smoke detection chamber 211 is provided with a light-shielding wall 214 (not shown).

[0036] As shown in FIG. 9(a), the smoke introduction cover 23 is formed with a plurality of labyrinth plates 232. The labyrinth plates 232 are bent to block external light. However, as in the first embodiment, the inner ends of the labyrinth plates 232, i.e., the portions located on the inside, are oriented in a direction offset from the center of the smoke introduction cover 23. Therefore, in the smoke introduction section, outside air A entering the inside between the plurality of labyrinth plates 232 hits the slope 231b of the hill-shaped portion 231 at an angle. The hill-shaped portion 231 protrudes toward the opening 221. In the smoke introduction section, the outside air A inside the labyrinth plates 232 rotates along the slope 231b and rises toward the smoke detection chamber 211. The smoke detection chamber 211 is provided on the optical bench 21, similar to the smoke detection chamber 111 in the first embodiment.

[0037] When viewed from above or below, the centers of the smoke detection chamber 211 and the opening 221 are the same as the centers of the optical bench 21, the optical bench cover 22, and the smoke introduction cover 23. As shown in Fig. 9, in the smoke introduction cover 23 of Example 2, the hill-shaped portion 231 as a whole is offset in the direction of arrow B from the center of the smoke detection chamber 211 and the opening 221. The shape of the hill-shaped portion 231 is a truncated cone, with the centers of the top 231a and the bottom 231c aligned in the planar direction, and the cross section of the hill-shaped portion 231 being an isosceles trapezoid, as shown in Fig. 9(b). On the other hand, since the center of the bottom surface 231c is offset in the direction of arrow B from the centers of the smoke detection chamber 211 and the opening 221, the labyrinth plates 232 located in the tip direction of arrow B, i.e., in the direction where the gap between the hill-shaped portion 231 and the outer periphery of the smoke introduction cover 23 is narrow, are small, and the labyrinth plates 232 located in the base direction, i.e., in the direction where the gap between the hill-shaped portion 231 and the outer periphery of the smoke introduction cover 23 is wide, are large. As in Example 1, the tip direction of arrow B is the direction away from the light-shielding wall 214. The labyrinth plates 232 provided on the side farther from the light-shielding wall 214 are smaller than the labyrinth plates 232 provided on the side closer to the light-shielding wall 214.

[0038] In Example 2, the entire hill-shaped portion 231 is shifted from the center of the smoke detection chamber 211 and the opening 221 in the direction of arrow B, which is the direction away from the light-shielding wall 214, so that the center of the top 231a is shifted in the direction of arrow B, as shown in Figures 9(a) and 9(b). Due to the above-mentioned configuration of the hill-shaped portion 231, outside air A rising along the slope 231b is introduced into the smoke detection chamber 211 at a position shifted in the direction of arrow B, which is the direction away from the light-shielding wall 214.

[0039] In the second embodiment, too, the outside air A circulates counterclockwise around the hill-shaped portion 231 on the top surface of the smoke inlet cover 23 shown in Fig. 9(a). As shown in Fig. 6, the outside air A circulates clockwise on the optical bench 21 when viewed from below. Therefore, the flow of the outside air A does not become significantly disturbed inside the smoke detection chamber 211, and flows smoothly, enabling early detection of a fire while suppressing false fire alarms.

[0040] In the hill-shaped portion 231 of the smoke introduction cover 23 of the second embodiment, the angle of the slope 231b connecting the periphery of the bottom surface 231c to the periphery of the top surface 231a does not change depending on the position. Therefore, the rotation and rising of the outside air A is performed more smoothly than in the smoke introduction cover 13 of the first embodiment. [Example]

[0041] The smoke detector 3 of Example 3 differs from the smoke detectors 1 and 2 of Examples 1 and 2 in the shape of the smoke inlet cover. FIG. 10 shows the smoke inlet cover 33 of Example 3. FIG. 10(a) is a top view of the smoke inlet cover 33, and FIG. 10(b) is a side cross-sectional view. The smoke detector 3 of Example 3 is a combination of an optical bench 31 (not shown), an optical bench cover 32 (not shown), and a smoke inlet cover 33, as in Examples 1 and 2. The optical bench 31 and the optical bench cover 32 of Example 3 are the same as the optical benches 11 and 21 and the optical bench covers 12 and 22 of Examples 1 and 2. The smoke inlet section, which introduces outside air A from the outside, from the underside of the optical bench cover 32 to the smoke inlet cover 33 communicates with a smoke detection chamber 311 (not shown) through an opening 321 (not shown). As in Examples 1 and 2, the smoke detection chamber 311 is provided with a light-shielding wall 314 (not shown).

[0042] When viewed from above or below, the centers of the smoke detection chamber 311 and the opening 321 are the same as the centers of the optical bench 31, the optical bench cover 32, and the smoke introduction cover 33. As shown in FIG. 10(a), the smoke introduction cover 33 has multiple labyrinth plates 332 formed thereon. The labyrinth plates 332 are bent to block external light, but as in Examples 1 and 2, the portion of the smoke introduction cover 33 located inside the labyrinth plates 332 faces in a direction offset from the center of the smoke introduction cover 33. The labyrinth plates 332 of Example 3 are similar to the labyrinth plates 232 of Example 2. The bottom surface 331c of the hill-shaped portion 331 is also positioned in the same position as the bottom surface 231c of Example 2. The hill-shaped portion 331 protrudes toward the opening 321. In the smoke introduction section, outside air A entering the interior through the gaps between the multiple labyrinth plates 332 hits the slope 331b of the hill-shaped portion 331 obliquely.

[0043] Unlike Example 2, in Example 3, the center of top 331a of hill-shaped portion 331 is offset from the center of bottom 331c in the direction of arrow B, as shown in Figures 10(a) and 10(b). In addition, slope 331b connecting the periphery of bottom 331c to the periphery of top 331a has different angles with bottom 331c depending on the position. Example 3 has a feature that combines the features of smoke introduction cover 13 of Example 1 and the features of smoke introduction cover 23 of Example 2.

[0044] In Example 3, the center of rotation of the outside air A in Example 2 can be further shifted horizontally away from the light-shielding wall 314. Also, as in Example 3, by shifting the position of the bottom surface and further shifting the position of the top surface as viewed from the bottom surface, the labyrinth plate 332 positioned in the direction of arrow B can be made larger without changing the center of rotation of the outside air A in Example 2. This increases the distance separating the inside and outside of the labyrinth plate 332 positioned in the direction of arrow B in the smoke introduction section, thereby improving light-blocking properties. Furthermore, in the smoke detector 1 of Example 1, the hill-shaped portion 331 of the smoke introduction cover 33 of Example 3 can reduce the angle change with the bottom surface 331c depending on the position of the slope 331b connecting from the periphery of the bottom surface 331c to the periphery of the top surface 331a. Therefore, the rotation and rising of the outside air A occurs more smoothly than with the smoke introduction cover 13 of Example 1. [Example]

[0045] The smoke detector 4 of Example 4 shifts the center of rotation of the outside air A horizontally away from the light-shielding wall depending on the position of the opening. The smoke detector 4 of Example 4 also combines an optical bench 41 (not shown), an optical bench cover 42, and a smoke introduction cover 43 (not shown), similar to Examples 1 to 3. The smoke detector 4 of Example 4 differs from the smoke detectors 1 to 3 of Examples 1 to 3 in the shape of the optical bench cover 42. FIG. 11 shows a bottom view of the combination of the optical bench cover 42 and the optical bench 41 of Example 4. Most of the optical bench 41 is covered by the optical bench cover 42, with a portion of the smoke detection chamber 411 visible behind the opening 421. The smoke introduction section, from the underside of the optical bench cover 42 to the smoke introduction cover 43, through which outside air A is introduced from the outside, is connected to the smoke detection chamber 411 via the opening 421.

[0046] 11, opening 421 provided in optical bench cover 42 is offset in the direction of arrow B, and opening 421 is eccentric in a direction moving horizontally away from light-shielding wall 414 (not shown) when viewed from the center of smoke detection chamber 411. Light-shielding wall 414 provided in smoke detection chamber 411 of optical bench 41 is covered by optical bench cover 42 and cannot be seen, but is located in the direction of the base end of arrow B when viewed from opening 421, that is, in the direction in which the gap between smoke detection chamber 411 and the outer periphery of optical bench cover 42 is wide.

[0047] The smoke inlet cover 43 of Example 4 may be any type that has light-blocking properties and can form a two-stage light-blocking structure. It may be used in place of the smoke inlet cover 53 in the smoke detector 5 shown in the conventional example, or may be used in place of the smoke inlet covers 13, 23, and 33 in the smoke detectors 1 to 3 of Examples 1 to 3. It may also be one that does not have a hill-shaped portion.

[0048] In the fourth embodiment, the opening 421 is eccentric in a direction horizontally away from the baffle wall when viewed from the center of the smoke detection chamber 411, so that the baffle wall 414 is unlikely to obstruct the flow of the outside air A.

[0049] In the above embodiment, the tops of the hill-shaped portions 131, etc. are disk-shaped, but they may be other shapes, such as an oblong disk. Also, while the tops of the hill-shaped portions 131, etc. are flat, they may be curved or have a pointed apex. Also, the shape of the smoke detection chamber and opening may be other shapes, such as a circle without any protrusions.

[0050] Furthermore, the specific configuration is not limited to the embodiments, and the present invention includes design changes within the scope of the present invention. Furthermore, the above-described examples and modifications can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in the purpose, configuration, etc. [Explanation of symbols]

[0051] 1 smoke detector, 11 optical base, 111 smoke detection chamber, 112 light emitting element, 112a light emitting element chamber, 113 light receiving element, 113a light receiving element chamber, 114 light shielding wall, 115 smoke detection wall, 115a wall fold, 12 optical base cover, 121 opening, 121a protrusion, 13 smoke introduction cover, 131 hill-shaped portion, 131a top, 131b slope, 131c bottom, 132 labyrinth plate, 133 cover plate, 2 smoke detector, 21 optical table, 211 smoke detection chamber, 214 light-shielding wall, 22 optical table cover, 221 opening, 23 smoke introduction cover, 231 hill-shaped portion, 231a top, 231b slope, 231c bottom, 232 labyrinth plate, 3 smoke detector, 31 optical table, 311 smoke detection chamber, 314 light-shielding wall, 32 optical table cover, 321 opening, 33 smoke introduction cover, 331 hill-shaped portion, 331a top, 331b slope, 331c bottom, 332 labyrinth plate, 4 Smoke detector, 41 Optical bench, 411 Smoke detector room, 414 Light-shielding wall, 42 Optical bench cover, 421 Opening, 43 Smoke introduction cover, 5 Smoke detector, 51 Optical table, 511 Smoke detection chamber, 512 Light emitting element, 512a Light emitting element chamber, 513 Light receiving element, 513a Light receiving element chamber, 514 Light shielding wall, 515 Smoke detection wall, 52 Optical table cover, 521 Opening, 53 Smoke introduction cover, 531 Hill-shaped portion, 531a Top, 531b Slope, 532 Labyrinth plate A. Outside air

Claims

1. a smoke detection chamber that detects smoke that has flowed into the chamber, the smoke detection chamber including a light-emitting unit, a light-receiving unit, and a light-shielding wall positioned between the light-emitting unit and the light-receiving unit; a smoke introduction section communicating with the smoke detection chamber and through which outside air is introduced from the outside; an opening that connects the smoke introduction section and the smoke detection chamber; In a smoke detector equipped with The smoke introduction section is provided with a plurality of curved labyrinth plates and hill-like portions that protrude toward the opening on the inside of the plurality of labyrinth plates, The height of the hill-like portion is the same as or approximately the same as the labyrinth plate, the top of the hill-shaped portion is eccentric in a direction away from the light-shielding wall in the horizontal direction when viewed from the center of the smoke detection chamber, A smoke detector characterized in that outside air is introduced from the smoke inlet section into the smoke detection chamber through the opening while rotating, and the center of rotation is located eccentrically in a direction away from the light-shielding wall in the horizontal direction when viewed from the center of the smoke detection chamber.

2. A smoke detector as described in Claim 1, characterized in that the center of the bottom surface of the hill-shaped portion is at approximately the same position as the center of the smoke detection chamber.

3. a smoke detection chamber that detects smoke that has flowed into the chamber, the smoke detection chamber including a light-emitting unit, a light-receiving unit, and a light-shielding wall positioned between the light-emitting unit and the light-receiving unit; a smoke introduction section communicating with the smoke detection chamber and through which outside air is introduced from the outside; an opening that connects the smoke introduction section and the smoke detection chamber; In a smoke detector equipped with The smoke introduction section is provided with a plurality of curved labyrinth plates and a hill-like portion protruding toward the opening, the top of the hill-shaped portion is eccentric in a direction away from the light-shielding wall in the horizontal direction, and the bottom surface of the hill-shaped portion is not eccentric from the top, The outside air is introduced from the smoke introduction section into the smoke detection chamber through the opening while rotating, and the center of rotation is located in a direction away from the light-shielding wall in the horizontal direction, 1. A smoke detector according to claim 1, wherein the labyrinth plate provided on the side farther from the light-shielding wall is smaller than the labyrinth plate provided on the side closer to the light-shielding wall.

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