JP2015191466A - Smoke detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a smoke detector for increasing the received quantity of the light scattered by smoke particles by a light receiving unit, regardless of the diameters, large or small, of the smoke particles.SOLUTION: An optical bench 1 of the smoke detector includes: a smoke inflow unit 2 into which smoke flows; a light emission unit 5 for radiating light to the inside of the smoke inflow unit 2; a light receiving unit 6 for receiving the light that is radiated from the light emission unit 5 and is scattered in the smoke inflow unit 2; and a polarization member 5a for polarizing, to perpendicularly polarized light, the light radiated from the light emission unit 5 in the direction perpendicular to a scattering plane that includes the light emission axis of the light emission unit 5 or the light receiving axis of the light receiving unit 6 and is parallel to the smoke inflow unit 2. The angle formed by the light emission axis and the light receiving axis is 45° to 180°.

Description

  The present invention relates to a smoke detector including a light emitting unit.

  As a smoke detector, for example, a photoelectric spot type detector that includes a light-emitting unit and a light-receiving unit and detects smoke using light scattering has been proposed. In Patent Document 1, a light emitting unit including a light emitting element having a half-value angle of 10 degrees or less is used, and a scattering angle in which the optical axis of the light emitting unit and the optical axis of the light receiving unit intersect is in a range of 60 ° to 80 °. A scattered light smoke detector is disclosed. In this prior art, an LED that emits infrared light is used as a light emitting element. In Patent Document 1, the light emitted from the light emitting element is directly received by the light receiving unit by regulating the half-value angle of the light emitting element and regulating the scattering angle between the optical axes of the light emitting unit and the light receiving unit. It is something that tries to suppress that.

JP-A-7-72073 (Claim 1, page 2)

  Since the scattered light type smoke detector disclosed in Patent Document 1 is not subjected to any processing on the light emitted from the light emitting unit, among the smoke particles, particles having a small particle size and particles having a large particle size are included. In any case, no consideration is given to efficiently receiving the light scattered by the smoke particles.

  The present invention has been made against the background of the above problems. Among the smoke particles, any of the particles having a small particle diameter and the particles having a large particle diameter can receive light scattered by the smoke particles. It provides a smoke detector that increases the amount of light received.

  A smoke detector according to the present invention includes a smoke inflow portion into which smoke flows, a light emitting portion that emits light into the smoke inflow portion, and a light receiving portion that receives light emitted from the light emitting portion and scattered by the smoke inflow portion. And a polarizing member that polarizes the light emitted from the light emitting unit into the vertical direction by polarizing the light in the vertical direction with respect to the smoke inflow unit and the horizontal scattering surface including the light emitting axis in the light emitting unit or the light receiving axis in the light receiving unit. The angle between the light emitting axis and the light receiving axis is 45 ° to 180 °.

  According to this invention, the light irradiated from the light emission part is vertical polarization, and an angle is 45 degrees-180 degrees. For this reason, the light quantity which the light-receiving part light-receives in the light scattered by the smoke particle can increase both in the particle | grains with a small particle diameter and a particle | grain with a large particle diameter among smoke particles.

It is a front view which shows the optical stand 1 of the smoke detector which concerns on Embodiment 1. FIG. It is a side view which shows the optical stand 1 of the smoke detector which concerns on Embodiment 1. FIG. It is a bottom view which shows the optical stand 1 of the smoke detector which concerns on Embodiment 1. FIG. FIG. 3 is a circumferential cross-sectional view showing smoke detector 4 in the first embodiment. FIG. 3 is a circumferential cross-sectional view showing the smoke entry portion 3 in the first embodiment. 3 is an axial cross-sectional view showing the optical stand 1 of the smoke detector according to Embodiment 1. FIG. 3 is an axial cross-sectional view showing the optical stand 1 of the smoke detector according to Embodiment 1. FIG. 3 is a perspective view showing light emitted from the light emitting unit 5 in Embodiment 1. FIG. 3 is a schematic diagram illustrating positions of a light emitting unit 5 and a light receiving unit 6 according to Embodiment 1. FIG. 4 is a graph showing a relationship between a scattering angle Gs and scattered light intensity Is in the first embodiment.

  Hereinafter, embodiments of a smoke detector according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Moreover, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

Embodiment 1 FIG.
FIG. 1 is a front view showing the optical stand 1 of the smoke detector according to the first embodiment, and FIG. 2 is a side view showing the optical stand 1 of the smoke detector according to the first embodiment. The optical stand 1 of the smoke detector will be described with reference to FIGS. As shown in FIG. 1 and FIG. 2, the optical bench 1 is provided with a smoke intrusion portion 3 that serves as an entrance for smoke, and smoke that is provided above the smoke entrance portion 3 and detects smoke that has entered from the smoke entrance portion 3. The smoke inflow part 2 provided with the detection part 4 is provided. The smoke inflow portion 2 has, for example, a substantially cylindrical shape, and the smoke intrusion portion 3 and the smoke detection portion 4 are stacked in the thickness direction (arrow Z direction). Such an optical bench 1 is installed in a main body (not shown) of the smoke detector and will not be described in detail, but the smoke entrance of the optical bench 1 is inserted into the main body of the smoke detector. A smoke inlet is formed in accordance with the position of the portion 3.

  FIG. 3 is a bottom view showing the optical stand 1 of the smoke detector according to the first embodiment. As shown in FIG. 3, the smoke detection unit 4 in the smoke inflow unit 2 includes a light emitting unit 5 and a light receiving unit 6. Each of the light emitting unit 5 and the light receiving unit 6 is provided, for example, at an outer peripheral edge of the smoke detecting unit 4 in the smoke inflow unit 2. And the light emission part 5 irradiates light inside the smoke inflow part 2, The light can be made into blue light, for example, However, You may use the light of another wavelength. Examples of this include ultraviolet light, green light, red light, and infrared light. The blue light is light having a wavelength of about 440 nm to 480 nm, for example. The light receiving unit 6 receives light emitted from the light emitting unit 5 and scattered by the smoke inflow unit 2. In addition, when the light irradiated from the light emission part 5 is blue light, the light-receiving part 6 should just be provided with the function to receive blue light at least, but is provided with the function to receive the light in other than that wavelength. It may be.

  FIG. 4 is a circumferential cross-sectional view showing the smoke detector 4 in the first embodiment, and is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 4, the smoke detection unit 4 in the smoke inflow unit 2 includes a labyrinth region 41 and a smoke detection region 43. The labyrinth region 41 is a region where light is scattered and trapped so that noise light does not occur in the smoke detection region 43, and a plurality of labyrinths 42, which are columnar members with sharp tips pointing toward the center, are arranged circumferentially. It is configured by being installed. The light emitted from the light emitting unit 5 is scattered by the plurality of labyrinths 42. The labyrinth 42 extends in the thickness direction (arrow Z direction) of the smoke inflow portion 2 and has an acute triangular prism shape. As a result, the light reflected by the labyrinth 42 is reduced in the component of the vertical polarization and remains in the component of the horizontal polarization.

  The smoke detection area 43 is an area provided inside the labyrinth area 41 where smoke is detected. Note that a polarizing member 5 a is attached to the light emitting unit 5, whereby the light emitted from the light emitting unit 5 is polarized.

  When there is no smoke in the smoke detection unit 4, the light emitted from the light emitting unit 5 is scattered by the plurality of labyrinths 42 provided in the labyrinth region 41, and the light intensity is attenuated, so that it is not received by the light receiving unit 6. . On the other hand, when smoke enters the smoke detection unit 4, the light emitted from the light emitting unit 5 is scattered by the smoke in the smoke detection region 43 and received by the light receiving unit 6. As described above, the optical platform 1 of the smoke detector detects smoke by receiving light by the light receiving unit 6.

  FIG. 5 is a circumferential cross-sectional view showing the smoke intrusion portion 3 in the first embodiment, and is a cross-sectional view taken along the line BB in FIG. As shown in FIG. 5, a plurality of light shielding portions 31 that are bent plate-like members are circumferentially installed in the smoke intrusion portion 3 in the smoke inflow portion 2. These light shielding portions 31 block external light from entering the inside of the smoke intrusion portion 3 when external light is about to enter from the outside of the optical stand 1 of the smoke detector, thereby preventing the external light from entering the inside of the smoke intrusion portion 3. To do. On the other hand, between these light shielding parts 31, there are openings 32, and smoke enters the inside of the smoke entry part 3 from these openings 32.

  6 is an axial sectional view showing the optical stand 1 of the smoke detector according to the first embodiment, and is a sectional view taken along the line CC in FIG. FIG. 7 is an axial sectional view showing the optical stand 1 of the smoke detector according to the first embodiment, and is a DD sectional view in FIG. As shown in FIG. 6 and FIG. 7, the smoke intrusion unit 3 and the smoke detection unit 4 are connected to each other with the central part of the smoke intrusion unit 3 and the central part of the smoke detection unit 4 being opened to each other. A smoke passage 21 through which smoke passes is provided. The smoke that has entered the inside of the smoke intrusion unit 3 enters the inside of the smoke detection unit 4 through the smoke passage 21.

  Next, the light irradiated from the light emission part 5 is demonstrated. FIG. 8 is a perspective view showing light emitted from light emitting unit 5 in the first embodiment. As shown in FIG. 8, the optical axis in the light emitting part 5 is defined as a light emitting axis Ae, and the plane that includes the light emitting axis Ae and is horizontal to the smoke inflow part 2 is defined as a scattering surface Fs. In the first embodiment, the light emitted from the light emitting unit 5 is vertically polarized light polarized in a direction perpendicular to the scattering surface Fs (arrow Z direction). That is, the polarizing member 5a converts the light emitted from the light emitting unit 5 into the vertical polarization that is polarized in a direction perpendicular to the smoke inflow unit 2 and the horizontal scattering surface Fs including the light emitting axis Ae in the light emitting unit 5. It is.

  FIG. 9 is a schematic diagram showing the positions of the light emitting unit 5 and the light receiving unit 6 in the first embodiment. As shown in FIG. 9, an optical axis in the light receiving unit 6 is a light receiving axis Ar, and an angle formed between the light emitting axis Ae and the light receiving axis Ar is a scattering angle Gs. In the first embodiment, the angle formed by the light emitting axis Ae and the light receiving axis Ar, that is, the scattering angle Gs is 90 °.

  Next, the operation of the optical stand 1 of the smoke detector according to the first embodiment will be described. FIG. 10 is a graph showing a relationship between the scattering angle Gs and the scattered light intensity Is in the first embodiment, and the scattering angle when vertical or horizontal polarization of blue light is applied to smoke particles having different particle diameters. This shows the relationship between Gs and scattered light intensity Is. FIG. 10 is a graph obtained by correcting the result of the simulation by an empirical rule.

  In FIG. 10, the horizontal axis represents the scattering angle Gs, and the vertical axis represents the scattered light intensity Is. In FIG. 10, solid lines (graphs 1 and 2) indicate vertically polarized light polarized in the direction perpendicular to the scattering surface Fs (arrow Z direction), of which the thick line (graph 1) has a large particle diameter. The scattered light intensity Is when vertically polarized light is applied to smoke particles is shown. On the other hand, the thin line (graph 2) indicates the scattered light intensity Is when vertical polarized light is applied to smoke particles having a small particle diameter.

  A broken line (graphs 3 and 4) indicates horizontal polarized light polarized in a horizontal direction (arrow Y direction) with respect to the scattering surface Fs, and a thick line (graph 3) is horizontal to smoke particles having a large particle diameter. The scattered light intensity Is upon applying polarized light is shown. On the other hand, the thin line (graph 4) shows the scattered light intensity Is when horizontal polarized light is applied to smoke particles having a small particle diameter.

  The particle diameter uses a particle diameter parameter α which is a relative particle size with respect to the wavelength λ of light as an index. When the particle radius of the smoke particles is r, the particle size parameter α is obtained from the following formula (1).

  α = 2πr / λ (1)

  In graphs 1 and 3 in FIG. 10, α = 10, particles are large with respect to the wavelength λ of light, and white smoke is assumed. On the other hand, in graphs 2 and 4 in FIG. 10, α = 1, particles are small with respect to the wavelength of light, and black smoke is assumed. Note that white smoke is smoke generated mainly by smoldering, and black smoke is smoke generated mainly by flammable combustion.

  In FIG. 10, when comparing the graph 1 and the graph 2 that are vertically polarized light, when the scattering angle Gs is 45 ° to 180 °, the difference between the scattered light intensity Is in the graph 1 and the scattered light intensity Is in the graph 2 is small. That is, the light receiving unit 6 can receive the light scattered by these particles in a well-balanced manner for both the small particle size and the large particle size. When the scattering angle Gs is 75 ° to 150 °, the difference between the scattered light intensity Is in the graph 1 and the scattered light intensity Is in the graph 2 is further reduced. Furthermore, when the scattering angle Gs is 90 ° to 120 °, the difference between the scattered light intensity Is in the graph 1 and the scattered light intensity Is in the graph 2 is drastically reduced.

  On the other hand, in FIG. 10, when comparing the graph 3 and the graph 4 that are horizontally polarized light, when the scattering angle Gs is 120 ° to 180 °, the scattered light intensity Is in the graph 3 and the scattered light intensity Is in the graph 4 The difference is small. As described above, the light emitted from the light emitting unit 5 may be horizontally polarized light, and the scattering angle Gs may be 120 ° to 180 °. In this case, both the particles having a small particle diameter and the particles having a large particle diameter are The light receiving unit 6 can receive the light scattered by the particles with a good balance.

  As described above, in the first embodiment, the light emitted from the light emitting unit 5 is vertically polarized light that includes the light emitting axis Ae and is polarized in a direction perpendicular to the smoke inflow unit 2 and the horizontal scattering surface Fs. Further, the angle formed by the light emitting axis Ae and the light receiving axis Ar, that is, the scattering angle Gs is 90 °. As shown in FIG. 10, the vertical polarization, that is, the graph 1 and the graph 2 have a small difference between the scattered light intensity Is in the graph 1 and the scattered light intensity Is in the graph 2 when the scattering angle Gs is 90 °. For this reason, regardless of the particle diameter of the smoke, the light receiving unit 6 can receive the light scattered by the smoke. Thus, this Embodiment 1 increases the light quantity which the light-receiving part 6 light-receives in the light scattered by the smoke particle also in any of a particle with a small particle diameter and a particle with a large particle diameter among smoke particles. Can be made. In order to obtain such a result, in the first embodiment, the polarizing member 5a is attached to the light emitting unit 5 and the light emitted from the light emitting unit 5 is vertically polarized. A similar result can be obtained even if only polarized light is allowed to pass through the scattered light received by the light receiving unit 6 with the polarizing member attached thereto. In this case, the scattered light directed toward the light receiving unit 6 is vertically polarized light that includes the light receiving axis Ar and is polarized in the vertical direction with respect to the smoke inflow unit 2 and the horizontal scattering surface Fs. When the scattering angle Gs formed with the axis Ar is 90 °, horizontal polarization is not received, and the same effect is obtained.

  In the first embodiment, the scattering angle Gs is 90 °, but the scattering angle Gs is the stability of the scattered light intensity Is detected by the light receiving unit 6 and the scattered light intensity detected by the light receiving unit 6. It can be appropriately changed depending on the magnitude of Is or the like. Further, as described above, the light reflected by the labyrinth 42 has a component of vertical polarization reduced and a large amount of component of horizontal polarization remains. In the first embodiment, since the light emitted from the light emitting unit 5 is vertically polarized light, the light reflected by the labyrinth 42 is reduced, and thus light that becomes noise can be reduced.

  In the first embodiment, the light emitting unit 5 that emits blue light is used. Particles with a smaller particle size are easier to detect as the wavelength is shorter. In the first embodiment, since the light emitting unit 5 that emits blue light is used, smoke including particles having a small particle size can be detected.

  In the above embodiment, the smoke inflow part 2 is exemplified by the smoke detector having the two-stage structure of the smoke intrusion part 3 and the smoke detection part 4, but the smoke inflow part 2 has a one-stage structure. You may comprise.

  DESCRIPTION OF SYMBOLS 1 Optical stand, 2 Smoke | flow inflow part, 3 Smoke inflow part, 4 Smoke detection part, 5 Light emission part, 5a Polarizing member, 6 Light reception part, 21 Smoke flow path, 31 Light shielding part, 32 Opening part, 41 Labyrinth area | region, 42 Labyrinth 43 Smoke detection area.

Claims (4)

A smoke inflow section into which smoke flows,
A light emitting part for irradiating light inside the smoke inflow part;
A light receiving unit that receives light emitted from the light emitting unit and scattered by the smoke inflow unit;
A polarizing member that converts light emitted from the light emitting unit into a vertical polarization by polarizing the light in the vertical direction with respect to the scattering surface horizontal to the smoke inflow unit including the light emitting axis in the light emitting unit or the light receiving axis in the light receiving unit. And having
An angle formed by the light emitting axis and the light receiving axis is 45 ° to 180 °. The smoke detector according to claim 1, wherein an angle formed by the light emitting axis and the light receiving axis is 75 ° to 150 °. The smoke detector according to claim 1 or 2, wherein an angle formed between the light emitting axis and the light receiving axis is 90 ° to 120 °. The smoke sensor according to any one of claims 1 to 3, wherein the light emitted from the light emitting unit is blue light.

Images