JP2010086378A - Photoelectric smoke detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric smoke detector capable of preventing wrong alarms from being issued, even if steam flows into a smoke detection unit. <P>SOLUTION: A smoke detecting unit 1 includes an installation section 20; and a smoke inlet section 10. The installation section 20 includes a light-emitting element 22 for emitting light to the inside of the installation section 20; and a light-receiving element 23 for receiving the light emitted from the light-emitting element 22. The smoke inlet section 10 includes a plurality of wall members 12 for preventing external light from entering the smoke inlet section 10; and a smoke inlet formed between the plurality of wall members 12. The installation section 20 and the smoke inlet section 10 are arranged so as to overlap each other, with the smoke inlet section 10 being positioned at a lower side of the installation section and are made to communicate with each other through an opening 13. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photoelectric smoke detector, and more particularly, to a photoelectric smoke detector that can prevent erroneous reporting due to steam flowing into a smoke detector.

  As a conventional photoelectric smoke detector, for example, “a smoke detector cover 11 is detachably attached to the lower surface of the smoke detector body 5. A plurality of labyrinth members 13 are provided inside the peripheral wall 12 of the smoke detector cover 11. The labyrinth member 13 is formed so as to facilitate the inflow of smoke from the outside and to block the light from the outside. Are integrally provided to prevent insects from invading and generating scattered light, and a plurality of smoke inlets 15 are formed in the peripheral wall 12 of the smoke detecting section cover 11. Holders 16 and 17, a light shielding member 18, and a mounting part 19 are integrally formed on the lower surface of the smoke detector body 5. The light receiving element 20 and a test infrared LED are housed in the holder 16. Infrared LED21 The light shielding member 18 shields the infrared light emitted from the smoke detecting infrared LED 21 so as not to directly enter the light receiving element 20. The protrusion portion 22 formed on the smoke detecting portion cover 11 is attached to the attachment portion 19. Is inserted, and the smoke detector cover 11 is detachably attached to the smoke detector main body 5. "(For example, refer to Patent Document 1) has been proposed.

Japanese Patent No. 2787001 (paragraphs 0014 to 0016, FIGS. 2 and 3)

  A smoke detector in a conventional photoelectric smoke detector (for example, see Patent Document 1) includes a light emitting element (infrared LED for smoke detection) and a light receiving portion in a smoke inflow portion in which a wall (labyrinth member) is formed at the peripheral portion. An element was provided. That is, in the conventional photoelectric smoke detector, the mounting portion provided with the light emitting element and the light receiving element is not separated from the smoke inflow portion. Therefore, when steam generated in a cooking place or a bathroom of a hotel room flows into the smoke detector, there is a problem that a false alarm is generated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a photoelectric smoke detector that can prevent false alarms even if steam flows into the smoke detector.

  The photoelectric smoke detector according to the present invention has a smoke detector and a fire discriminating unit for judging a fire based on an output signal of the smoke detector, and when the fire discriminator judges a fire, a fire signal In the photoelectric smoke detector that outputs, the smoke detection unit includes a mounting unit and a smoke inflow unit, the mounting unit irradiates light inside the mounting unit, and the light emitting device And a light receiving element that receives scattered light generated by the smoke particles of the smoke detecting section, and the smoke inflow section has a plurality of wall bodies that prevent external light from entering the smoke inflow section. And a smoke inlet formed between the walls, and the mounting portion and the smoke inflow portion are arranged so that the smoke inflow portion is on the lower side, It is what is communicated.

  Moreover, the height dimension of the said mounting part is larger than the height dimension of the said smoke inflow part.

  In the present invention, the smoke detecting section is divided into a mounting section provided with a light emitting element and a light receiving element and a smoke inflow section. Further, the mounting portion and the smoke inflow portion are arranged so that the smoke inflow portion is on the lower side, and communicated with each other through the opening. For this reason, the steam flowing into the smoke inflow portion has a large inertia because the mass of the particles is large. Therefore, since it is difficult to change the flow state, it passes through the smoke inflow portion with almost no flow into the mounting portion. On the other hand, the smoke flowing into the smoke inflow portion has a small inertia because the mass of the particles is small. Therefore, since the flow state is easily changed, it flows into the mounting portion through the opening. Then, the light receiving element receives the scattered light when the light emitted from the light emitting element is scattered by the smoke flowing into the mounting part, and the fire determining part determines a fire. Therefore, it is possible to obtain a photoelectric smoke detector that can determine a fire without erroneous reporting even if steam flows into the smoke detector (smoke inlet).

  Moreover, since the height dimension of the mounting part is larger than the height dimension of the smoke inflow part, the smoke that has flowed into the smoke inflow part is more likely to flow into the mounting part. Therefore, the photoelectric smoke detector can determine a fire with higher accuracy.

Embodiment.
In the following embodiments, a case will be described in which the present invention is applied to a fire alarm device in which an alarm device such as a push button switch or a buzzer is provided in the configuration of the photoelectric smoke detector.

  1 is a longitudinal sectional view showing a smoke detector of a fire alarm device according to an embodiment of the present invention, FIG. 2 is a bottom view of the smoke detector, FIG. 3 is a right side view of the smoke detector, and FIG. AA sectional view of FIG. 1 and FIG. 5 are BB sectional views of FIG. These FIG. 1 to FIG. 5 show the scales partially different. Hereinafter, the fire alarm device according to the present embodiment will be described with reference to FIGS. In the following description, description will be made in accordance with the vertical and horizontal directions in FIG.

  The smoke detector 1 of the fire alarm 100 is composed of a smoke inflow portion 10 and a mounting portion 20. The smoke inflow portion 10 has a substantially cylindrical shape, and includes a plate member 11 and a wall body 12. The plate member 11 has a substantially disk shape, and an opening 13 is formed at a substantially central portion. Further, on the outer peripheral portion of the plate member 11, convex portions 11 a and convex portions 11 b are formed at corresponding positions of a light emitting element holder 26 and a light receiving element holder 27 described later. A plurality of, for example, substantially J-shaped wall bodies 12 are erected in a substantially annular shape with a predetermined interval at a peripheral portion on the lower surface side of the plate member 11. Thereby, the smoke inflow part 10 is formed in a substantially cylindrical shape so that the upper surface part is covered with the plate member 11. The wall body 12 prevents external light from entering the smoke inflow portion 10. A space (predetermined interval) formed between the wall bodies 12 serves as a smoke inlet 14 for smoke to flow into the smoke inflow portion 10. The opening on the lower surface side of the smoke inflow portion 10 is closed by the lid body 16, and the inside of the smoke inflow portion 10 is a dark box. In addition, an insect net (not shown) is provided on the side surface of the smoke inflow portion 10 in order to prevent insects from entering from the smoke inlet 14.

  A mounting portion 20 is provided above the smoke inflow portion 10. The mounting unit 20 includes an optical bench 21, a light emitting element 22, a light receiving element 23, a light shielding member 24, and the like. The optical bench 21 has a substantially cylindrical shape with an opening at the bottom, and is provided with a light emitting element holder 26 for accommodating the light emitting element 22 and a light receiving element holder 27 for accommodating the light receiving element 23. The outer end portions of the light emitting element holder 26 and the light receiving element holder 27 are provided so as to protrude from the outer peripheral portion of the optical bench 21. In a state where the smoke inflow portion 10 is provided below the mounting portion 20, the smoke inflow portion 10 that is a dark box closes the opening of the optical bench 21. Thereby, the inside of the optical bench 21 is also a dark box. In addition, in a state where the smoke inflow portion 10 is provided below the mounting portion 20, the smoke inflow portion 10 and the mounting portion 20 communicate with each other through the opening 13. In the present embodiment, the height dimension of the mounting portion 20 is larger than the height dimension of the smoke inflow portion 10.

  The light emitting element holder 26 is provided with a pair of holding members 26a made of hooks, for example. The light emitting element 22 is accommodated in the light emitting element holder 26 while being held between the holding members 26 a. At this time, the lead portion of the light emitting element 22 is bent at a substantially right angle, is inserted through a through hole 26 b formed in the light emitting element holder 26, and protrudes from the upper surface portion of the optical bench 21.

  The light receiving element 23 is provided in the shield case 28 and is housed in the light receiving element holder 27 together with the shield case 28. The shield case 28 has a substantially rectangular tube shape with an opening in a range facing the light receiving part of the upper part and the light receiving element 23. The shield case 28 is provided with a holding member 28 a made of, for example, a pressing piece. The light receiving element 23 is sandwiched between the side surface portion of the shield case 28 and the holding member 28 a and is provided in the shield case 28. A convex portion 28b is formed on the upper portion of the shield case 28. By inserting the convex portion 28b into an opening formed in the circuit board 2 and soldering, the shield case 28 and the light receiving element 23 are fixed. ing.

  In a state where the light emitting element 22 and the light receiving element 23 are housed in the optical bench 21, the light emitting element 22 is provided so that the irradiation range 22b faces substantially the center of the optical bench 21, and the light receiving element 23 receives the light receiving element 23. The range 23 b is provided so as to face the substantially central portion of the optical bench 21. In addition, the optical axis 22a of the light emitting element 22 and the optical axis 23a of the light receiving element 23 are provided so as to be substantially parallel in a side view and at a predetermined angle in a plan view. That is, smoke is detected by the smoke detection unit 25 that is a superposition of the irradiation range 22 b of the light emitting element 22 and the light receiving range 23 b of the light receiving element 23. More specifically, the light receiving element 23 receives light scattered by the smoke that is emitted from the light emitting element 22 and enters the smoke detection unit 25.

  Further, a light shielding member 24 is erected on the optical bench 21 on the side where the angle formed by the optical axis 22a of the light emitting element 22 and the optical axis 23a of the light receiving element 23 is an acute angle. The cross-sectional shape of the light shielding member 24 in a plan view is, for example, a substantially hexagonal shape, and is a shape in which a corner on the center side of the optical bench 21 is cut out in a substantially U shape. Thus, the light shielding member 24 is formed with an edge portion 24a and an edge portion 24b. The edge portion 24a prevents the light receiving element 23 from directly receiving the light emitted from the light emitting element 22. The edge portion 24b prevents the light receiving element 23 from receiving the light irregularly reflected by the edge portion 24a.

  The mounting portion 20 is mounted on the lower surface portion of the circuit board 2. A plurality of electrical components (not shown) are mounted on the circuit board 2, and these electrical components constitute a fire determination unit 3. In a state where the mounting unit 20 is mounted on the circuit board 2, the light emitting element 22 and the light receiving element 23 and the fire determination unit 3 are electrically connected. And the fire discrimination | determination part 3 discriminate | determines whether the fire broke out based on the light reception amount which the light receiving element 23 detects. The amount of received light detected by the light receiving element 23 is output to the fire discriminating unit 3 by voltage or the like, for example.

  The smoke detector 1 and the circuit board 2 are provided in a housing (not shown) in which air permeability to the smoke inflow portion 10 is ensured, and constitute a fire alarm 100. And this fire alarm 100 is installed in monitoring spaces, such as a house, a building, and a hotel room, for example. In a state in which the fire alarm 100 is attached to the ceiling surface of the monitoring space, the fire alarm 100 is installed with the smoke inflow portion 10 on the lower side, as shown in FIG.

  The fire alarm device 100 uses, for example, a battery 30 that is a lithium battery as a drive source. That is, the battery 30 supplies power to the light emitting element 22 of the smoke detector 1, the fire determination unit 3 of the circuit board 2, and the like. The battery 30 is provided on the side of the circuit board 2 on the side where the angle formed by the optical axis 22a of the light emitting element 22 and the optical axis 23a of the light receiving element 23 is an acute angle. The battery 30 is provided so as to cut out part of the upper surface portion and the side surface portion of the mounting portion 20. That is, the battery storage part that stores the battery 30 is provided so as to cut out part of the upper surface part and the side part of the mounting part 20. By providing the battery 30 (battery storage part) so as to cut out part of the upper surface part and the side part of the mounting part 20, the fire alarm device 100 can be reduced in size and thickness. Note that the notched portion of the mounting portion 20 is closed to prevent external light from entering.

  In addition, the battery 30 (battery storage part) does not necessarily need to be provided at the position shown in the present embodiment, and may be provided so as to cut out a part that does not hinder the smoke detection function of the mounting part 20. . In other words, the battery 30 (battery storage unit) cuts out the portion of the mounting unit 20 that avoids the irradiation range 22b of the light emitting element 22 to the smoke detection unit 25 and the light receiving range 23b of the light receiving element 23 to the smoke detection unit 25. What is necessary is just to form. On the side where the angle formed by the optical axis 22a of the light emitting element 22 and the optical axis 23a of the light receiving element 23 is an acute angle, the smoke detection unit 25 is separated by the light shielding member 24, so a battery 30 (battery storage unit) is provided. This is the place where the influence on the smoke detection function of the mounting unit 20 is minimal. Therefore, in the present embodiment, a part of the upper surface portion and the side surface portion of the mounting portion 20 on the side where the angle formed by the optical axis 22a of the light emitting element 22 and the optical axis 23a of the light receiving element 23 is an acute angle is cut out. Thus, a battery 30 (battery storage part) is provided.

(Description of operation)
Then, operation | movement of the fire alarm device 100 which concerns on this Embodiment is demonstrated.
FIG. 6 is a longitudinal sectional view showing the smoke detector of the fire alarm according to the embodiment of the present invention. 6 is a cross-sectional view taken along the line CC of FIG. FIG. 6A is a longitudinal cross-sectional view showing a state where smoke has flowed into the smoke detector section 1, and the smoke flow in the smoke detector section 1 is indicated by a dashed arrow. FIG. 6B is a longitudinal sectional view showing a state in which steam has flowed into the smoke detector section 1, and the flow of steam in the smoke detector section 1 is indicated by broken arrows.

  As shown in FIG. 6A, smoke generated by the fire flows along the ceiling surface of the monitoring space and flows into the smoke inflow section 10 of the smoke detector section 1. At this time, the light shielding member 24 is provided only in the mounting portion 20. That is, the light shielding member 24 is not provided in the smoke inflow portion 10. Further, neither the light emitting element 22 nor the light receiving element 23 is provided in the smoke inflow portion 10. Therefore, the light shielding member 24 or the like does not block the flow of smoke flowing into the smoke inflow portion 10, and the smoke inflow characteristics of the smoke inflow portion 10 are improved. Note that the light shielding member 24 is not necessarily provided only in the mounting portion 20, and the tip portion of the light shielding member 24 is inserted into the smoke inflow portion 10 as long as the smoke inflow characteristics of the smoke inflow portion 10 do not deteriorate. May be. By providing the light shielding member 24 with such a length that the tip portion is inserted into the smoke inflow portion 10, it is possible to more reliably prevent the light receiving element 23 from directly receiving the light emitted by the light emitting element 22. .

  Smoke has low inertia because of its small particle mass. Therefore, since the flow state is easily changed, the smoke that has flowed into the smoke inflow portion 10 flows into the mounting portion 20 through the opening portion 13. When smoke flows into the mounting portion 20, the light emitted from the light emitting element 22 is scattered by the smoke. This scattered light is received by the light receiving element 23. That is, the amount of light received by the light receiving element 23 changes. The light receiving element 23 outputs a detection value (voltage or the like) corresponding to the amount of received light to the fire determination unit 3. Based on this detection value, the fire determination unit 3 determines whether or not a fire has occurred. When it is determined that a fire has occurred, the fire determination unit 3 warns the surroundings that a fire has occurred by a light emitting element such as an LED or an alarm device (not shown) such as a buzzer. In the present embodiment, since the height dimension of the mounting portion 20 is larger than the height dimension of the smoke inflow portion 10, the smoke that has flowed into the smoke inflow portion 10 easily flows into the mounting portion 20. . For this reason, the fire discrimination | determination part 3 (fire alarm device 100) can judge a fire accurately.

  On the other hand, as shown in FIG. 6B, steam has a large inertia because the mass of the particles is large. Therefore, since it is difficult to change the flow state, the steam that has flowed into the smoke inflow portion 10 passes through the inflow portion 10 almost without flowing into the mounting portion 10. For this reason, in the mounting part 20, the light irradiated by the light emitting element 22 is not scattered (or less) by steam. Therefore, even if steam flows into the smoke inflow unit 10 (smoke detection unit 1), the fire determination unit 3 (fire alarm 100) does not erroneously determine that there is a fire.

  In the fire alarm 100 configured as described above, the smoke detector 1 is divided into a mounting part 20 provided with the light emitting element 22 and the light receiving element 23 and a smoke inflow part 10. Further, the mounting portion 20 and the smoke inflow portion 10 are arranged so that the smoke inflow portion 10 is on the lower side, and communicated with each other through the opening 13. For this reason, even if steam flows into the smoke inflow part 10, the fire alarm device 100 that can determine a fire can be obtained without misreporting.

  Moreover, since the height dimension of the mounting part 20 is larger than the height dimension of the smoke inflow part 10, the smoke that has flowed into the smoke inflow part 10 easily flows into the mounting part 20. For this reason, the fire discrimination | determination part 3 (fire alarm device 100) can judge a fire accurately.

  Furthermore, even if the fire alarm 100 is installed with its orientation changed to a side wall surface that is substantially orthogonal to the ceiling surface, smoke and steam flow as shown in FIGS. 6 (a) and 6 (b). The same effect can be obtained.

  In the present embodiment, the present invention is applied to the scattered light type fire alarm device 100. However, the present invention may be applied to a dimming type fire alarm device. It is of course possible to implement the present invention on a fire detector.

It is a longitudinal cross-sectional view which shows the smoke detection part of the fire alarm which concerns on embodiment of this invention. It is a bottom view which shows the smoke detection part of the fire alarm which concerns on embodiment of this invention. It is a right view which shows the smoke detection part of the fire alarm which concerns on embodiment of this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a longitudinal cross-sectional view which shows the smoke detection part of the fire alarm which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Smoke detection part, 2 circuit board, 3 fire discrimination part, 10 smoke inflow part, 11 board member, 11a convex part, 11b convex part, 12 wall body, 13 opening part, 14 smoke inflow port, 16 lid body, 20 mounting Part, 21 optical bench, 22 light emitting element, 22a optical axis, 22b irradiation range, 23 light receiving element, 23a optical axis, 23b irradiation range, 24 light shielding member, 24a edge part, 24b edge part, 25 smoke detection part, 26 light emitting element Holder, 26a Holding member, 26b Through hole, 27 Light receiving element holder, 28 Shield case, 28a Holding member, 28b Protruding part, 30 Battery, 100 Fire alarm.

Claims (2)

In a photoelectric smoke detector that has a smoke detector and a fire discriminator that judges a fire based on an output signal of the smoke detector, and outputs a fire signal when the fire discriminator judges a fire,
The smoke detector includes a mounting part and a smoke inflow part,
The mounting part is
A light-emitting element that irradiates light inside the mounting part; and a light-receiving element that receives the scattered light that is emitted from the light-emitting element and is generated by the smoke particles of the smoke detector part,
The smoke inlet is
A plurality of walls that prevent external light from entering the smoke inlet, and a smoke inlet formed between the walls;
The mounting portion and the smoke inflow portion are
Arranged so that the smoke inflow part is on the lower side,
A photoelectric smoke detector characterized in that it communicates with an opening.   The photoelectric smoke detector according to claim 1, wherein a height dimension of the mounting portion is larger than a height dimension of the smoke inflow portion.

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