Smoke detection device

Abstract

To provide a smoke detection device in which reduction in accuracy of smoke detection due to deposition of dirt is hard to occur.SOLUTION: A smoke detection device 1 comprises a light-emitting section 93 which emits light toward a detection region R3 in a container 91, a light-receiving section 94 which receives a part of light reflected on particles in air in the detection region R3 in the light which is emitted by the light-emitting section 93, and a signal processing section which determines the presence / absence of smoke on the basis of a signal indicating an intensity of the light which is received by the light-receiving section 94. An inflow port E1 and an outflow port E2 for air which are provided in the container 91 are positioned outside of the detection region R3. The inflow port E1 and the outflow port E2 are enclosed by a partition plate 11 having an opening H2. Therefore, in powder dust contained in air flowing from the inflow port E1 into the container 91, the quantity of powder dust which arrives at the detection region R3 is reduced and the quantity of light which is directed toward the light-receiving section 94 by being reflected on the powder dust deposited on an inner side face, etc. of the container 91 in the detection region R3 is reduced. As a result, reduction in accuracy of smoke detection due to deposition of dirt is hard to occur.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device for detecting smoke. [Background technology]

[0002] 2. Description of the Related Art There is a smoke detection device that detects the generation of smoke in a monitored space by detecting smoke contained in the monitored space.

[0003] A smoke detection device generally includes a smoke sensor and a container that houses the sensor. The container has an inlet, which is an opening through which air flows from the outside of the monitored space into the inside, and an outlet, which is an opening through which air flows from the inside to the outside.

[0004] For example, Patent Document 1 discloses a smoke detection device that includes a container having an air inlet and an air outlet, and a sensor that detects smoke housed inside the container. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-60196 Summary of the Invention [Problem to be solved by the invention]

[0006] The air flowing into the container that houses the sensor in a smoke detection device contains dust particles of a size similar to or smaller than smoke particles. Some of this dust does not escape from the outlet, but instead adheres to the inside surface of the container, forming dirt. Dirt inside the container reduces the accuracy of the sensor's smoke detection.

[0007] In view of the above circumstances, the present invention provides a smoke detection device that is less susceptible to deterioration in smoke detection accuracy due to the accumulation of dirt, compared to smoke detection devices according to the prior art. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention proposes a smoke detection device comprising: a light-emitting unit; a light-receiving unit arranged so that its light-receiving axis intersects the light-emitting axis of the light-emitting unit; a container that houses the light-emitting unit and the light-receiving unit and has an air inlet and an air outlet; a blower that generates an air flow from the inlet into the container; and a detection unit that detects smoke in the air flowing within the container based on a signal generated by the light-receiving unit, wherein the inlet and the outlet are arranged on each of two opposing sides of the wall of the container, sandwiching a plane that includes the light-emitting axis and the light-receiving axis, and at least one of the inlet and the outlet is positioned outside a detection area where the light-emitting area of ​​the light-emitting unit and the light-receiving area of ​​the light-receiving unit overlap when viewed perpendicular to the plane. [Effects of the Invention]

[0009] According to the smoke detection device of the present invention, the surrounding areas of the inlet or outlet, which are prone to becoming dirty, are located outside the detection area, which is the area in the container that houses the light-emitting unit and the light-receiving unit where the smoke particles to be detected float, and therefore the accuracy of smoke detection is less likely to be reduced by the accumulation of dirt. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram schematically illustrating the configuration of a smoke detection device according to an embodiment. [Figure 2] FIG. 10 is a diagram schematically illustrating the configuration of a smoke detection device according to a modified example. [Figure 3] FIG. 1 is a diagram schematically illustrating the configuration of a smoke detection device according to a conventional technique. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Comparative Example] A smoke detection device according to the prior art will be described below to be compared with the smoke detection device according to an embodiment of the present invention.

[0012] Fig. 3 is a diagram showing a schematic configuration of a smoke detection device 9 according to the prior art. Fig. 3(A) is a diagram showing a main body 911 of a container 91 that houses a sensor included in the smoke detection device 9, and the main components housed in the container 91. Fig. 3(B) is a diagram showing a lid 912 that closes an opening on the top surface of the main body 911 of the container 91. The container 91 is made up of the main body 911 and the lid 912. Fig. 3(C) is a diagram showing a blower mechanism 92 arranged on the back surface of the main body 911 of the container 91.

[0013] The smoke detection device 9 includes a light emitting unit 93, a light receiving unit 94, and a stray light reducing unit 95 as components housed in a container 91.

[0014] The light emitting unit 93 emits light for detecting smoke. The light emitted from the light emitting unit 93 in the direction of the light emitting axis A1 passes through the light emitting region R1.

[0015] The light receiving unit 94 receives light traveling from the light receiving region R2 along the light receiving axis A2 and outputs a signal indicating the intensity of the received light to a signal processing unit (not shown). The light receiving unit 94 is disposed so that the light receiving axis A2 intersects with the light emitting axis A1.

[0016] Most of the light received by the light-receiving unit 94 is light that is emitted from the light-emitting unit 93, reflected by particles contained in the air within detection area R3, which is the area where light-emitting area R1 and light-receiving area R2 overlap, and directed toward the light-receiving unit 94. These particles include trace amounts of dust, so even under normal circumstances when no smoke is being emitted in the monitored space, the light-receiving unit 94 receives light reflected by the dust and outputs a signal indicating the intensity of the received light. However, under normal circumstances, the signal output by the light-receiving unit 94 is extremely small.

[0017] On the other hand, in an emergency when smoke is occurring in the monitored space, the air within detection region R3 contains many smoke particles in addition to trace amounts of dust, so the light receiving unit 94 receives light reflected by these particles and outputs a signal larger than normal. When a signal larger than normal is output from the light receiving unit 94, the signal processing unit determines that smoke is occurring in the monitored space and performs predetermined processing, such as sending data indicating a warning to a higher-level system such as a fire alarm.

[0018] The stray light reduction unit 95 is a component that prevents light emitted from the light-emitting unit 93 that is not reflected by particles contained in the air in the light-emitting region R1 from reflecting off the inner wall of the container 91 and heading toward the light-receiving unit 94. The stray light reduction unit 95 has a reflecting member 951 and a light-shielding plate 952.

[0019] Reflecting member 951 is a member formed so that its shape, when viewed in the perpendicular direction to a plane (hereinafter referred to as the reference plane) containing light-emitting axis A1 and light-receiving axis A2, is a mountain shape made up of two reflecting surfaces with their convex surfaces arranged back to back. That is, reflecting member 951 forms reflecting surfaces M1 and M2 shown in Fig. 3(A). Reflecting surfaces M1 and M2 are concave reflecting surfaces that reflect light.

[0020] The light-shielding plate 952 is a light-shielding plate that is disposed so as to surround the reflective member 951 when viewed in the direction perpendicular to the reference plane, and has an opening H1 on the light-emitting axis A1 through which light passes. A large number of projections and recesses are formed on the inner side of the light-shielding plate 952, i.e., on the surface facing the reflective member 951.

[0021] Of the light emitted from the light receiving unit 94, light that is not reflected by particles contained in the air within the light-emitting region R1 passes through the opening H1 and reaches the reflecting surface M1, is reflected by the reflecting surface M1, and heads toward the inner surface of the light-shielding plate 952, and is then absorbed while being repeatedly reflected by the inner surface of the light-shielding plate 952, the reflecting surface M1, and the reflecting surface M2. Note that a small portion of the light that enters the inside of the light-shielding plate 952 exits the light-shielding plate 952 from the opening H1, but this amount is so small that it does not have a significant effect on smoke detection.

[0022] The main body 911 of the container 91 has one or more light-shielding plates 9111 arranged perpendicular to the light-emitting axis A1. Each of the light-shielding plates 9111 has a circular opening centered on the light-emitting axis A1, and a light-emitting region R1 is formed so as to pass through the opening. The light-shielding plates 9111 serve to block and absorb light emitted from the light-emitting unit 93 that is traveling in a direction other than along the light-emitting axis A1, and to prevent dust in the air that flows from the outside to the inside of the container 91 from reaching the light-emitting unit 93, thereby reducing the adhesion of dirt to the light-emitting unit 93.

[0023] The main body 911 of the container 91 also has one or more light-shielding plates 9112 arranged perpendicular to the light-receiving axis A2. Each of the light-shielding plates 9112 has a circular opening centered on the light-receiving axis A2, and a light-receiving region R2 is formed so as to pass through the opening. The light-shielding plates 9112 serve to block and absorb light that is reflected in an area other than the detection region R3 within the container 91 and travels toward the light-receiving unit 94 in a direction not aligned with the light-receiving axis A2, and also serve to prevent dust in the air flowing from the outside to the inside of the container 91 from reaching the light-receiving unit 94, thereby reducing the adhesion of dirt to the light-receiving unit 94.

[0024] Although three light-shielding plates 9111 and three light-shielding plates 9112 are shown in FIG. 3A, the number of the light-shielding plates 9111 and the number of the light-shielding plates 9112 are not limited to three.

[0025] The main body 911 of the container 91 has, on its bottom surface, an inlet E1 which is an opening through which air passes from the outside to the inside of the container 91. Furthermore, the lid 912 of the container 91 has, on its top surface, an outlet E2 which is an opening through which air passes from the inside to the outside of the container 91. The bottom surface of the main body 911 and the top surface of the lid 912 are two surfaces that face each other with a reference plane in between.

[0026] The positions of the inlet E1 and the outlet E2 are approximately in the center of the detection area R3 when viewed in the direction perpendicular to the reference plane. Therefore, the inlet E1 and the outlet E2 are arranged in the same position when viewed in the direction perpendicular to the reference plane when the lid 912 is attached to the main body 911. The entire shortest air flow path from the inlet E1 to the outlet E2 is located within the detection area R3.

[0027] The blower mechanism 92 has a box-shaped member 921 arranged on the rear surface of the main body 911 , and a blower section 922 and a filter 923 arranged inside the box-shaped member 921 .

[0028] The box-shaped member 921 has an opening on the lower side in Figure 3(C), and forms a flow path for air moving in the direction of arrow B1 shown in Figure 3(C), i.e., from the monitored space outside the smoke detection device 9 toward the inlet E1.

[0029] The blower 922 has a fan rotated by, for example, a motor, and generates a flow of air that moves from the outside of the smoke detection device 9 inside the box-shaped member 921 in the direction of arrow B1 and then flows from the inlet E1 into the container 91.

[0030] The filter 923 captures dust particles contained in the air blown from the outside of the smoke detection device 9 into the container 91 by the blower 922, which are larger than smoke particles, and prevents such dust particles from entering the container 91.

[0031] Air flowed into container 91 from inlet E1 by blower mechanism 92 passes through detection region R3 within container 91, and then flows out of smoke detection device 9 from outlet E2. A sensor made up of light-emitting unit 93, light-receiving unit 94, and signal processing unit detects smoke in the air passing through detection region R3. This concludes the description of the configuration of smoke detection device 9 according to the prior art.

[0032] Generally, dirt tends to accumulate more easily in the areas around the inlet E1 and the outlet E2 on the inner surface of the container 91 than in other areas. In the smoke detection device 9 according to the prior art, the inlet E1 and the outlet E2 are located within the detection region R3. Therefore, in the smoke detection device 9, part of the light emitted from the light-emitting unit 93 is reflected by dirt adhering to the area around the inlet E1 or the area around the outlet E2 and directed toward the light-receiving unit 94. This increases the signal output by the light-receiving unit 94, resulting in a false detection of smoke even when no smoke particles are present in the air within the detection region R3.

[0033] [Embodiment] A smoke detection device 1 according to one embodiment of the present invention will be described below. Fig. 1 is a diagram schematically illustrating the configuration of the smoke detection device 1. In Fig. 1, among the components of the smoke detection device 1, those that are common to or correspond to components of the smoke detection device 9 are assigned the same reference numerals as those assigned to the components of the smoke detection device 9.

[0034] Fig. 1(A) is a diagram showing a main body 911 of a container 91 of a smoke detection device 1 and the main components housed in the container 91. Fig. 1(B) is a diagram showing a lid 912 of the container 91 of the smoke detection device 1. Fig. 1(C) is a diagram showing a blower mechanism 92 of the smoke detection device 1.

[0035] The smoke detection device 1 differs from the smoke detection device 9 in the following points.

[0036] (1) Location of inlet E1 In the smoke detection device 1, the position of the inlet E1 is outside the light-emitting region R1 and outside the light-receiving region R2, and therefore, the position of the inlet E1 is necessarily outside the detection region R3 as well.

[0037] (2) Location of outlet E2 In the smoke detection device 1, the inlet E1 and the outlet E2 are arranged at the same position when viewed in the direction perpendicular to the reference plane, as in the smoke detection device 9. Therefore, in the smoke detection device 1, the position of the inlet E1 is different from that in the smoke detection device 9, and therefore the position of the outlet E2 is also different from that in the smoke detection device 9.

[0038] That is, in the smoke detection device 1, the position of the outlet E2 is outside the light-emitting region R1 and outside the light-receiving region R2, and therefore, the position of the outlet E2 is necessarily outside the detection region R3 as well.

[0039] Furthermore, in the smoke detection device 1, the entire shortest air flow path from the inlet E1 to the outlet E2 is outside the light-emitting region R1 and outside the light-receiving region R2. Consequently, the entire shortest air flow path from the inlet E1 to the outlet E2 is necessarily outside the detection region R3.

[0040] (3) Addition of partition plate 11 The main body 911 of the container 91 of the smoke detection device 1 has a partition plate 11 as a component not provided in the smoke detection device 9. The partition plate 11 is a plate-shaped member arranged to surround the inlet E1 when viewed in the direction perpendicular to the reference plane. The partition plate 11 has an opening H2 that serves as a flow path for air flowing in a direction along the reference plane.

[0041] In the smoke detection device 1 according to this embodiment, the outlet E2 is located at the same position as the inlet E1 when viewed in the direction perpendicular to the reference plane, and therefore the partition plate 11 is arranged to surround the outlet E2 as well. Therefore, the entire shortest air flow path from the inlet E1 to the outlet E2 is located within the area surrounded by the partition plate 11.

[0042] (4) Configuration of the stray light reduction unit 95 In the smoke detection device 1, the reflecting member 951 forms a curved single reflecting surface, reflective surface M1. That is, the shape of the reflecting member 951 included in the smoke detection device 1 is the same as the shape of the reflecting member 951 included in the smoke detection device 9, with the portion that forms the reflecting surface M2 removed.

[0043] In the smoke detection device 1, the space created by removing the portion of the reflecting member 951 that forms the reflecting surface M2 is surrounded by the partition plate 11, and the inlet E1 and the outlet E2 are disposed inside the space. Therefore, the area surrounded by the partition plate 11 and the area surrounded by the light-shielding plate 952 are adjacent to each other.

[0044] (5) Position of the blower mechanism 92 In the smoke detection device 1, the position of the inlet E1 is different from that in the smoke detection device 9, and therefore the position of the blower mechanism 92 is also different from that in the smoke detection device 9.

[0045] The above is an explanation of the differences between the smoke detection device 1 and the smoke detection device 9.

[0046] In the smoke detection device 1, when smoke particles are contained in the air that flows into the container 91 from the inlet E1, some of the smoke particles pass through the opening H2 and reach the detection region R3, reflecting the light emitted from the light-emitting element 93 toward the light-receiving element 94. Therefore, the smoke detection device 1 detects smoke.

[0047] In addition, experiments conducted by the inventors of the present application have confirmed that although the time required to detect smoke after it occurs in the monitored space using smoke detection device 1 is slightly longer than that required using smoke detection device 9, the accuracy of smoke detection by smoke detection device 1 is no less than that of smoke detection device 9.

[0048] In the above-described smoke detection device 1, the inlet E1 is located outside the light-emitting region R1, the light-receiving region R2, and the detection region R3, so even if dirt adheres to the peripheral area of ​​the inlet E1, the amount of light reflected by the dirt that reaches the light-receiving unit 94 is negligibly small.

[0049] Furthermore, in the smoke detection device 1, the outlet E2 is located outside the light-emitting region R1, the light-receiving region R2, and the detection region R3, so even if dirt adheres to the peripheral area of ​​the outlet E2, the amount of light reflected by the dirt that reaches the light-receiving unit 94 is negligibly small.

[0050] Furthermore, in the smoke detection device 1, the movement of dust particles in the air that has flowed into the container 91 from the inlet E1 toward the light-emitting region R1, the light-receiving region R2, or the detection region R3 is inhibited by the partition plate 11. This reduces the amount of dirt that adheres to the inner surfaces of the container 91 in the light-emitting region R1, the light-receiving region R2, and the detection region R3. This reduces the amount of light that is reflected by the dirt in these regions and travels toward the light-receiving unit 94.

[0051] As described above, in smoke detection device 1, the amount of light reflected by dirt inside container 91 and directed toward light receiving unit 94 is smaller than in smoke detection device 9. Therefore, in smoke detection device 1, the accuracy of smoke detection is less likely to be reduced by dirt than in smoke detection device 9.

[0052] [Variations] The above-described embodiment is a specific example of the present invention, and various modifications are possible within the scope of the technical concept of the present invention. Examples of such modifications are shown below. Note that two or more of the following modifications may be combined as appropriate.

[0053] (Variation 1) The positions of the inlet E1 and the outlet E2 in the above-described embodiment are merely examples, and other positions may be adopted as long as at least one of the inlet E1 and the outlet E2 is outside the detection region R3.

[0054] FIG. 2 is a diagram schematically illustrating the configuration of a smoke detection device 1 according to one example of this modification. Compared to the smoke detection device 1 according to the above-described embodiment (see FIG. 1), the smoke detection device 1 shown in FIG. 2 differs in the position of the inlet E1. That is, the inlet E1 is located inside the light-emitting region R1 and outside the detection region R3. As a result, the inlet E1 and the outlet E2 are disposed at different positions when viewed in the direction perpendicular to the reference plane. Furthermore, the inlet E1 is located outside the region surrounded by the partition plate 11. The entire shortest path of air from the inlet E1 to the outlet E2 is located outside the light-receiving region R2 (and therefore outside the detection region R3).

[0055] 2, the inlet E1 may be located inside the light-emitting region R1, while the outlet E2 may be located outside the light-emitting region R1. Alternatively, the inlet E1 may be located outside the light-emitting region R1, while the outlet E2 may be located inside the light-emitting region R1. In these cases, part of the shortest flow path for air from the inlet E1 to the outlet E2 is located within the light-emitting region R1.

[0056] The inlet E1 may be positioned outside the light-receiving region R2, while the outlet E2 may be positioned inside the light-receiving region R2. Alternatively, the inlet E1 may be positioned inside the light-receiving region R2, while the outlet E2 may be positioned outside the light-receiving region R2. In these cases, part of the shortest flow path for air from the inlet E1 to the outlet E2 is located within the light-receiving region R2.

[0057] The inlet E1 may be positioned outside the detection region R3, while the outlet E2 may be positioned inside the detection region R3. Alternatively, the inlet E1 may be positioned inside the detection region R3, while the outlet E2 may be positioned outside the detection region R3. In these cases, part of the shortest flow path for air from the inlet E1 to the outlet E2 will be located within the detection region R3.

[0058] As described above, when part of the shortest air flow path from the inlet E1 to the outlet E2 is located within the light-emitting region R1, the light-receiving region R2, or the detection region R3, the effect of reducing the amount of light reflected by dirt inside the container 91 and directed toward the light-receiving unit 94 is lower than when the entire shortest air flow path from the inlet E1 to the outlet E2 is outside those regions. However, since the distance between the shortest air flow path from the inlet E1 to the outlet E2 and the detection region R3 is shorter, the time from when smoke is generated in the monitored space until the smoke is detected is shorter.

[0059] (Variation 2) 2, the inlet E1 may be located outside the area surrounded by the partition plate 11. Also, the outlet E2 may be located outside the area surrounded by the partition plate 11. Also, the smoke detection device 1 does not have to be equipped with the partition plate 11.

[0060] When the inlet E1 is located outside the area surrounded by the partition plate 11, the amount of dust heading from the inlet E1 toward the light-emitting area R1, the light-receiving area R2, or the detection area R3 increases compared to when the inlet E1 is located inside the area surrounded by the partition plate 11, so the effect of reducing the amount of light reflected by dirt inside the container 91 and heading toward the light-receiving unit 94 is reduced.However, because the partition plate 11 does not obstruct the flow of air from the inlet E1 toward the detection area R3, the time it takes for smoke to be detected after it occurs in the monitored space is shortened.

[0061] When the outlet E2 is located outside the area surrounded by the partition plate 11, the amount of dust heading from the inlet E1 toward the light-emitting area R1, the light-receiving area R2, or the detection area R3 increases compared to when the outlet E2 is located inside the area surrounded by the partition plate 11, so the effect of reducing the amount of light reflected by dirt inside the container 91 and heading toward the light-receiving unit 94 is reduced.However, since the air flowing into the container 91 from the inlet E1 is forced to move toward the outlet E2, which is located in the same area outside the area surrounded by the partition plate 11 as the detection area R3, the time from when smoke occurs in the monitored space until the smoke is detected is shortened.

[0062] (Variation 3) The smoke detection device 1 may include a stray light reduction section 95 having the same configuration as the stray light reduction section 95 of the smoke detection device 9. [Explanation of symbols]

[0063] 1...smoke detection device, 9...smoke detection device, 11...partition plate, 91...container, 92...blowing mechanism, 93...light emitting unit, 94...light receiving unit, 95...stray light reduction unit, 911...main body, 912...lid, 921...box-shaped member, 922...blowing unit, 923...filter, 951...reflective member, 952...light shielding plate, 9111...light shielding plate, 9112...light shielding plate.

Claims

[Claim 1] A smoke detection device comprising: a light-emitting unit; a light-receiving unit arranged so that its light-receiving axis intersects with the light-emitting axis of the light-emitting unit; a container that houses the light-emitting unit and the light-receiving unit and has an air inlet and an air outlet; a blower that generates an air flow from the inlet toward the container; and a detector that detects smoke in the air flowing inside the container based on a signal generated by the light-receiving unit, a partition plate disposed in the wall of the container so as to surround at least one of the inlet and the outlet when viewed in a direction perpendicular to a plane including the light-emitting axis and the light-receiving axis, the partition plate having an opening that serves as a flow path for air flowing in a direction along the plane; Smoke detection device.

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