JPH0712724A - Fire alarm device and fire detecting method - Google Patents

Abstract

PURPOSE:To detect an occurrence of fire and a kind thereof by monitoring scattered light from smoke. CONSTITUTION:A fire alarm device comprises a first light emitting element 11, a polarizing filter 31, a light receiving element 21, a second light emitting element 12, a polarizing filter 32 and a light receiving element 22. With the use of these elements, a quantity of received polarized light which is parallel with the light scattering surface, and a quantity of received polarized light which is perpendicular to the scattering surface can be detected. The ratio between these light quantities which relates to a kind of smoke, is obtained from outputs from the light receiving elements 21, 22 by a computing part 4. Thus obtained ratio is compared with reference values which have been previously set in accordance with kinds of smoke to be detected, so as to determine whether a fire occurs or not. Thereby it is possible to detect an occurrence of fire and a kind of fire from the scattered light from the smoke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scattered light type fire alarm device and a fire detection method for detecting the presence or absence of a fire from the scattered light of smoke produced during a fire. In particular, the present invention relates to a fire alarm device and a fire detection method for detecting a fire according to the type of smoke by focusing on the relationship between the type of smoke and the scattering angle and degree of polarization of scattered light.
Above all, the present invention relates to a fire alarm device and a fire detection method in which the light source is a polarized light source having a predetermined polarization plane and the detection accuracy is improved.

[0002]

2. Description of the Related Art Conventionally, a fire alarm device of this type has been shown in FIG.
As shown in 0, the light emitting element 102 such as a light emitting diode is arranged toward the center portion X of the smoke detection chamber (smoke detection space). Further, the light receiving element 104 such as a photodiode is arranged so that its optical axis intersects the optical axis of the light emitting element 102 at a predetermined angle θ. Further, the light emitting element 102 constantly emits light having directivity in the optical axis direction. When smoke enters the smoke inspection space due to fire, the light receiving element 104 receives scattered light of the smoke in the smoke inspection space through a condenser lens (not shown).

That is, in normal times when no fire has occurred,
Since the smoke does not enter the smoke detection space, the intensity of scattered light reaching the light receiving element 104 is weak. On the other hand, smoke 106 from a fire
When enters into the smoke detection space, the intensity of scattered light reaching the light receiving element 104 increases. On the other hand, the intensity of scattered light incident on the light receiving element 104 has a correlation with the density of the smoke 106. Therefore, when the output level of the light receiving element 104 exceeds a predetermined threshold level, it is determined that a fire has occurred.

[0004]

However, such a conventional fire alarm device does not determine the type of smoke, but simply determines the presence or absence of a fire based on the concentration of smoke 106 in the smoke inspection space. Therefore, there is a problem that it is not possible to determine whether or not there is a fire depending on the type of smoke. That is, in reality, the color of smoke and the diameter of particles differ depending on the material of the combustion material such as plastic or wood. Therefore, smoke 1 in the smoke inspection space
Even if the concentration of 06 is the same, the intensity of scattered light reaching the light receiving element 104 varies depending on the material of the combustion material. Therefore, if a fire is judged on the basis of a unique threshold level regardless of the type of smoke, there is a problem that a non-fire is judged to be a fire or the fire judgment is delayed.

For example, in a room filled with cigarette smoke, it may be judged as a fire even though it is not a fire. Further, in the case of a fire caused by oil, the intensity of scattered light due to black smoke generated by the combustion of oil is weak. for that reason,
The fire will be detected after it has spread considerably, and the fire judgment will be delayed. On the other hand, in view of such an adverse effect, JP-A-2-213997 discloses that unpolarized light is used as a light source, and on the light receiving side, scattered light is divided into two orthogonal polarization components, and both components are received. Methods have been proposed to determine the presence of smoke within a volume ratio range. However, this method analyzes smoke particles as having a single size and ignores that smoke is a group of many particle groups having various particle sizes.

Therefore, this method has a problem that an error occurs with respect to actual smoke. In this method, unpolarized light is used as the light source, and the polarization plane of the light source is not considered with respect to the scattering surface. Therefore, the SN ratio of the amount of light received in each polarization direction in the light receiving element becomes low, and the output ratio actually obtained by the light receiving element becomes small, which is not practical.

Further, as a method for improving the accuracy of fire judgment by judging the type of smoke, Japanese Patent Laid-Open No. 5-12
There is an invention of 8381. JP-A-5-123381
In the invention of the publication, the intensity of light in different polarization directions is obtained, and the degree of change is calculated from this light intensity to determine the type of smoke. Then, the presence or absence of a fire is determined by comparing the light intensity with a preset threshold value according to the type of smoke.

However, even in this case, the non-polarized light is used as the light source as in the above-mentioned example, and the received light amount SN
The ratio is low. That is, the output ratio is 2 × 10 ^-1 : 4 with or without fire.
The problem of being as small as × 10 ^-1 has not been solved.
In view of such a conventional problem, the present invention focuses on the difference in the polarization characteristics of scattered light due to smoke particle groups, and can detect the presence or absence of a fire from the scattered light of smoke according to the type of smoke. An object is to provide a fire alarm device that can be used.

[0009]

In order to achieve the above-mentioned object, the present invention comprises a light emitting means for irradiating the smoke detection space with light and a light receiving means for receiving scattered light due to smoke. In a fire alarm device that determines the presence or absence of a fire by comparing the amount of light received at a predetermined reference value, the light emitting means is defined by the optical axis of the light emitting means and the optical axis of the light receiving means intersecting in the smoke inspection space. The polarized light parallel to the scattering surface and the polarized light perpendicular to the scattering surface are output, and the light receiving means receives the polarized light parallel to the scattering surface and the polarized light perpendicular to the scattering surface, and further receives each polarized light in the light receiving means. A photoelectric conversion means for detecting the amount, a calculation means for calculating the ratio of the amount of received light of polarized light parallel to the scattering surface converted by the photoelectric conversion means and polarized light perpendicular to the scattering surface, and the ratio obtained by the calculation means. The previously set for each type of smoke Of comparing the reference value, characterized in that a determination means for determining the presence or absence of fire for each type of smoke based on the reference value.

Further, in the present invention, preferably, the light emitting means is formed of the first light emitting element and the second light emitting element, and the light receiving means is the first light receiving element and the second light receiving element. The first light emitting element is formed on the first scattering surface defined in the smoke detection space by intersecting the optical axis of the first light emitting element and the optical axis of the first light receiving element. The second light-emitting element outputs parallel plane-polarized light, and the second light-emitting element has a second scattering defined by the optical axis of the second light-emitting element and the optical axis of the second light-receiving element intersecting each other. Plane polarized light perpendicular to the plane is output, the first light receiving element receives polarized light parallel to the first scattering surface, and the second light receiving element emits polarized light perpendicular to the second scattering surface. Further, the photoelectric conversion means detects the amount of light received by the first and second light receiving elements,
The calculation means may calculate the ratio of the received light amounts of the first and second light receiving elements converted by the photoelectric conversion means.

Further, the light receiving means is formed of a first light receiving element and a second light receiving element, and the light emitting means is constructed by intersecting the optical axis of the light emitting means with the optical axis of the first light receiving element. The plane polarized light parallel to the first scattering surface defined in the smoke detection space is output, the first light receiving element receives the polarized light parallel to the first scattering surface, and the second light receiving element is , The optical axis of the light emitting means and the optical axis of the second light receiving element intersect to receive polarized light perpendicular to the second scattering surface defined in the smoke detection space, and the first scattering surface and the first scattering surface The second scattering surface and the second scattering surface have a vertical positional relationship with each other, the photoelectric conversion unit detects the amount of light received by the first and second light receiving elements, and the calculation unit is the first and first photoelectric conversion units. It is also possible to calculate the ratio of the amount of light received by the two light receiving elements.

In addition, the light emitting means is formed by the first light emitting element and the second light emitting element which are alternately turned on,
The first light emitting element outputs plane-polarized light parallel to the first scattering surface defined in the smoke detection space by intersecting the optical axis of the first light emitting element and the optical axis of the light receiving means, The second light-emitting element is defined in the smoke detection space by the optical axis of the second light-emitting element and the optical axis of the light-receiving means intersecting each other.
The plane-polarized light perpendicular to the scattering surface is received, the light receiving means receives the polarized light parallel to the first scattering surface, and the first scattering surface and the second scattering surface are in a positional relationship perpendicular to each other. And the photoelectric conversion means detects the amount of light received in each of the light receiving means when the first and second light emitting elements are turned on, and the calculation means:
It is also possible to calculate the ratio of the received light amount when the first light emitting element is turned on and the received light amount when the second light emitting element is turned on, which is converted by the photoelectric conversion means.

Furthermore, the light emitting means outputs plane polarized light, and the plane polarized light is arranged on the entire surface of the light receiving means and the driving means for rotating the light emitting means to a position perpendicular or parallel to the scattering surface. A polarization filter that rotates in synchronism with the light emitting means is provided at a position where only the polarized light in the same direction as the plane polarized light is transmitted, and the photoelectric conversion means is arranged such that the plane polarized light output from the light emitting means is perpendicular to the scattering surface. And the amount of light received by the light receiving means in each of the parallel positions, and the calculating means calculates the amount of light received at the position where the plane polarized light converted by the photoelectric conversion means is perpendicular to the scattering surface and the plane polarized light. You may make it calculate the ratio with the light-receiving amount in the position parallel to a scattering surface.

On the other hand, according to the present invention, in order to achieve the above object, a light emitting means for irradiating the smoke inspection space with light,
In a fire detecting method for determining the presence or absence of a fire by providing a light receiving means for receiving scattered light due to smoke and comparing the amount of light received by the light receiving means with a predetermined reference value, the light emitting means emits light in the smoke detection space. The plane-polarized light parallel to the scattering plane defined by the intersection of the optical axis of the means and the optical axis of the light-receiving means and the plane-polarized light perpendicular to the scattering plane are output, and the plane-polarized light parallel to the scattering plane is output by the light-receiving means. The polarized light is received, the received light amount of each polarized light in the light receiving means is detected, and the ratio of the received light amount between the polarized light parallel to the scattering surface and the polarized light perpendicular to the scattering surface is calculated, and the ratio and the type of smoke. The reference value of the ratio set in advance is compared with each other, and the presence or absence of a fire is determined for each type of smoke based on the reference value.

Further, preferably, the light emitting means is formed of a first light emitting element and a second light emitting element, and the light receiving means is formed of a first light receiving element and a second light receiving element, Planar polarized light parallel to the first scattering surface defined in the smoke detection space by intersecting the optical axis of the first light emitting element and the optical axis of the first light receiving element is generated from the first light emitting element. A plane perpendicular to the second scattering surface defined by the output of the second light emitting element in the smoke detection space by intersecting the optical axis of the second light emitting element and the optical axis of the second light receiving element. Polarized light is output, the first light receiving element receives polarized light parallel to the first scattering surface, and the second light receiving element receives polarized light perpendicular to the second scattering surface. And the amount of light received by the second light receiving element, and the amount of light received by the first and second light receiving elements. Calculates the ratio is compared with the reference value preset the ratio for each type of said ratio and smoke, it may be determined whether the fire for each type of smoke based on the reference value.

Further, the light receiving means is formed of a first light receiving element and a second light receiving element, and the light emitting means intersects the optical axis of the light emitting means with the optical axis of the first light receiving element. Outputs plane-polarized light parallel to the first scattering surface defined in the smoke detection space by the first light receiving element,
Polarized light parallel to the first scattering surface is received, and the second light receiving element defines the optical axis of the light emitting means and the optical axis of the second light receiving element so as to be defined in the smoke inspection space. Polarized light perpendicular to the second scattering surface is received, the first scattering surface and the second scattering surface have a positional relationship perpendicular to each other, and the amount of light received by the first and second light receiving elements is detected. At the same time, the ratio of the amount of light received by the first and second light receiving elements is calculated, and the ratio and the preset value for each type of smoke are compared with a reference value,
The presence or absence of a fire may be determined for each type of smoke based on the reference value.

In addition, the light emitting means is formed of the first light emitting element and the second light emitting element which are alternately turned on,
The first light-emitting element outputs plane-polarized light parallel to the first scattering surface defined in the smoke detection space by intersecting the optical axis of the first light-emitting element and the optical axis of the light-receiving means, Second
The light-emitting element outputs the plane-polarized light perpendicular to the second scattering surface defined in the smoke detection space by intersecting the optical axis of the second light-emitting element and the optical axis of the light-receiving means, and receives the light. The polarized light parallel to the first scattering surface is received by the means, and the first scattering surface and the second scattering surface have a positional relationship perpendicular to each other, and when the first and second light emitting elements are turned on. The amount of light received by the light receiving means in each case is detected, and the ratio between the amount of light received when the first light emitting element is turned on and the amount of light received when the second light emitting element is turned on is calculated, and the ratio and the type of smoke are calculated. The presence or absence of a fire may be determined for each type of smoke based on a comparison with a reference value of the ratio set in advance for each.

Further, the light emitting means outputs plane polarized light, and the plane polarized light is disposed on the front surface of the light receiving means and the driving means for rotating the light emitting means to a position perpendicular or parallel to the scattering surface. A polarizing filter that rotates in synchronism with the light emitting means is provided at a position that transmits only polarized light in the same direction as the plane polarized light, and the plane polarized light output from the light emitting means is vertical and parallel to the scattering surface. The amount of light received by the light receiving means in each case is detected, and the ratio between the amount of light received at the position where the plane polarized light is perpendicular to the scattering surface and the amount of light received at the position where the plane polarized light is parallel to the scattering surface is calculated. However, the ratio may be compared with a reference value of the ratio preset for each type of smoke, and the presence or absence of a fire may be determined for each type of smoke based on the reference value.

In addition, the scattering angle may be 60 ° to 140 °, preferably 90 °. As a result, the ratio can be increased, and more reliable fire detection can be performed.

[0020]

According to the fire alarm device and the fire detection method of the present invention as described above, the following effects can be obtained. First, the ratio of the amount of polarized light received parallel to the scattering surface to the amount of polarized light received perpendicularly to the scattering surface is correlated with the type of smoke. In the present invention, the ratio of the received light amount of the polarized light parallel to the scattering surface and the received light amount of the polarized light perpendicular to the scattering surface, the reference value of the ratio preset according to the smoke to be detected is compared, Whether or not it is a fire is determined according to the type of smoke. Therefore, the presence or absence of a fire can be detected from the scattered light of smoke according to the type of smoke.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of a scattered light type fire alarm device according to the present invention, and the smoke inspection space will be described using a three-dimensional space of x, y, and z axes. In FIG. 1, as the first light emitting element 11 and the second light emitting element 12, for example, laser diodes that emit plane polarized light are used. The first light emitting element 11 has a polarization plane parallel to the first scattering surface 41 formed in the smoke detection space by the optical axis of the first light emitting element 11 and the optical axis of the first light receiving element 21. Will be arranged.

The second light emitting element 12 has a polarization plane on the second scattering surface 42 formed in the smoke detection space by the optical axis of the second light emitting element 12 and the optical axis of the second light receiving element 22. It is arranged so that it is perpendicular to it. That is, in the example shown in FIG. 1, the first light emitting element 11 is arranged so that the polarization plane is the xy plane, and the second light emitting element 12 is arranged so that the polarization plane is the yz plane.

The light emitted by the first light emitting element 11 and scattered by the smoke particle group has an appropriate scattering angle θ ₁ (light of the first light emitting element 11 with respect to the optical axis of the first light emitting element 11). Angle formed at the intersection of the axis and the optical axis of the first light receiving element 21. In the present invention, the angle is the side opposite to the first light emitting element 11. The same shall apply hereinafter). 31
Also, the light is received by the light receiving element 21.

Further, the light emitted by the second light emitting element 12 and scattered by the smoke particle group is the second light emitting element 12
The light is received by the second polarizing filter 32 and the second light receiving element 22 which are arranged at an appropriate scattering angle θ ₂ with respect to the optical axis of. That is, the first polarization filter 31 is arranged so that its polarization plane is parallel (xz plane) to the first scattering surface 41 formed by the first light emitting element 11 and the first light receiving element 21. It The second polarization filter 32 is arranged such that the polarization plane is perpendicular to the second scattering plane (yz plane).

On the other hand, the calculation unit 4 calculates the ratio of the respective outputs of the first light receiving element 21 and the second light receiving element 22. In addition, a reference value of the ratio of the outputs of the first light receiving element 21 and the second light receiving element 22 is set in the setting unit 5 in advance according to the detected smoke. In the judgment unit 6, the first light receiving element 21,
The ratio of each output of the second light receiving element 22 and the reference value of the setting unit 5 are compared to determine whether or not there is a fire depending on the type of smoke.

Here, the first light emitting element 11 and the first light receiving element 21 and the second light emitting element 12 and the second light receiving element 2
When smoke flows into the space where the optical axes of 2 intersect,
When reaching the first light receiving element 21 and the second light receiving element 22, a signal is generated in the first light receiving element 21 and the second light receiving element 22. According to the research by the present inventor, the first light receiving element 21
It became clear that each output of the light receiving element 22 has a peculiar relationship according to the type of smoke.

This relationship will be described in detail. First, it is known that the scattered light from particles such as smoke contains a polarization component. Therefore, the present inventor simulated the degree of polarization of scattered light by a plurality of different smoke particles. Then, it became clear that the magnitude of the polarization component of each scattered light differs depending on the type of smoke. Here, FIG.
Considering the electric field (→ E ₀ ) of the plane polarized light in the xz plane shown in (1), it is expressed by the following equation (Equation 1)
AN DE HULST "LightScattering by Small Particle
s "). In the following, the arrow" → "is used in the text (→
E), (→ a) and the like represent complex numbers for convenience. In addition, a _x in the formula represents a complex amplitude.

[0028]

[Equation 1]

The scattered light on the plane (1, r) forming an angle (deflection angle) φ with the xz plane by one particle due to the incident light is given by (→ E _r ) (→ E _l ). Let the scattering function of a particle of particle size a with respect to the scattering angle θ be (→ S ₁ (θ), → S ₂
(.Theta.)), ( _{.Fwdarw.E.sub.r} ) ( _{.fwdarw.E.sub.l} ) is expressed by the following equation (equation 2).

[0030]

[Equation 2]

The intensity I of the scattered light is expressed by the following equation (equation 3), where k is the wave number (k = 2π / λ) and r is the distance from the particle.

[0032]

[Equation 3]

Where F (θ, φ) is the scattering function,

[0034]

[Equation 4]

Next, let us consider a case where this scattered light is measured through a polarization filter. In FIG. 2, with respect to the coordinate system (1, r) on the reference plane, a polarization filter is arranged on the plane at an angle χ, and scattered light (→ E _l , → E _r ) is set to the coordinate system (h, p) on the plane χ. ) And coordinate conversion to scattered light (→ E _h , → E _p ).
Is expressed by the following equation (Equation 5).

[0036]

[Equation 5]

Therefore, the intensities I _h and I _p of the scattered light measured through the polarization filter can be obtained by the following equation (Equation 6).

[0038]

[Equation 6]

Also, the scattered light quantity Isca _h from the entire smoke layer,
Isca _p, as shown in the following equation (Equation 7), multiplied by the number of particles N _a intensity of scattered light for each particle size a I _h, the I _p, the integrated value it in range of the entire particle size .

[0040]

[Equation 7]

The results of estimating the polarization components of various smokes by the above theoretical analysis are shown in FIGS. FIG. 3 shows the smoke scattering efficiency i when the filter paper is smoked. Similarly, FIG.
Shows the scattering efficiencies i for kerosene burning and FIG. 5 for cigarette smoke. In addition, here, a change in the scattered light amount depending on the angle χ of the polarization filter when the polarization angle φ of the incident light is set to 0 ° and 90 ° for each type of smoke is shown.

According to FIGS. 3 to 5, when the polarization plane of the incident light and the angle of the polarization filter are equal, the amount of scattered light received under each condition becomes the maximum. That is, when φ = 0, χ =
0, and when φ = 90, the amount of received light becomes maximum at χ = 90. Furthermore, according to these figures,
It is clear that even at the same scattering angle, this maximum amount of received light changes depending on the polarization angle φ.

FIG. 6 shows two incident light polarization planes (φ = 0 °,
The ratio (i90 / i0) of the maximum received light amounts i90, i0 of cigarette, roasted meat, roasted fish and edible oil smoke at 90 °), smoke when the filter paper and cotton wick were smoked and kerosene smoke (i90 / i0) was calculated and plotted. The results are shown. According to FIG. 6, the ratio (i90 / i0) becomes maximum at any scattering angle φ = 90 ° for any smoke. Then, this ratio (i90 / i0) can be used as a parameter for identifying the type of smoke.

That is, the smoke discrimination parameter (i90 / i
0) is the first and second light receiving elements 21 and 2 shown in FIG.
The output ratio is 2 (i90 / i0 = output of the second light receiving element 22 / output of the first light receiving element 21). Therefore,
The smoke discrimination parameter (i90 / i0) and the scattered light type smoke sensor designed to have a scattering angle θ = 120 ° designed as shown in FIG.
If 0) is approximately "5" or more, it can be identified as cigarette smoke. Further, it can be determined that the oil is burned when "2" to "3" and smoldered of paper or the like when "2" or less.

Next, the operation of the scattered light type smoke detector will be described. For example, when installed to detect an oil fire, the smoke identification parameter (i90 / i0) is "2"-
The reference value of “3” is set in the setting unit 5 in advance. Further, when the device is installed to detect smoldering of paper or the like, a reference value having a smoke identification parameter (i90 / i0) of “2” or less is set in the setting unit 5 in advance. Then, the judging unit 6 compares the output ratios of the first and second light receiving elements 21 and 22 with this reference value, and outputs a fire signal when they match.

Therefore, according to the above embodiment, the reference value of the smoke discrimination parameter (i90 / i0) corresponding to the polarization characteristic of the smoke particle group is set in the setting unit 5 in advance, so that the smoke is irrelevant regardless of the smoke density. Whether or not there is a fire can be appropriately detected from the scattered light of the smoke according to the type of smoke. Further, since it is possible to prevent a false alarm due to smoke that is not caused by a fire such as a cigarette, it is possible to accurately notify the fire.

Furthermore, it is possible to distinguish between a fire that rapidly expands, such as petroleum, and a fire that gently expands, such as smoldering paper, so that appropriate fire fighting activities and evacuation guidance can be performed according to each fire. It can be carried out. Next, a second embodiment will be described with reference to FIG. In the present embodiment as well, there is no difference in making a fire judgment according to the type of smoke using the relationship between the type of smoke and the scattering angle and the degree of polarization, but the device configuration is different. FIG. 7 shows one light emitting element 1 and two light receiving elements 2.
1 and 22 and the polarization filters 31 and 32 are used. The light emitting element 1 is arranged so that the polarization plane is the yz plane.

The first light receiving element 21 and the polarization filter 31 are arranged on the y-axis and the polarization filter 31
Are arranged such that their plane of polarization is the yz plane. Further, the second light receiving element 22 and the polarization filter 32 are arranged on the x-axis, and the polarization filter 32 is arranged so that the polarization plane thereof is the xy plane. In this embodiment, similarly to the previous embodiment, the polarized light parallel to the first scattering surface 41 (that is, the yz plane) is incident on the first polarization filter 31. Further, polarized light perpendicular to the second scattering surface 42 (that is, the xy plane) enters the second polarizing filter 32. Therefore, the output ratio of the first and second light receiving elements 21 and 22 (i9
The smoke can be identified by 0 / i0).

In this embodiment, only the first polarizing filter 31 may be rotated by a motor or the like. That is, by rotating the first polarization filter 31, the same state as when the second polarization filter 32 is provided is obtained.
The position of the polarization plane of the first polarization filter 31 and the second
It is of course possible to stop the polarization filter at the position of the polarization plane of the polarization filter 32 and alternately identify the smoke by receiving the polarized light at each position. In this case, the second polarization filter 32 becomes unnecessary. Further, as the polarizing filter, an appropriate filter such as one using liquid crystal can be adopted.

FIG. 8 shows a third embodiment. In this embodiment, two light emitting elements 11 and 12, one light receiving element 2 and one polarization filter 3 are used. The polarization filter 3 is positioned so that the polarization plane is the xz plane. On the other hand, the first and second light emitting elements 11 and 12 are arranged on the z axis and the y axis, respectively. The first light emitting element 11 is arranged so that the polarization plane becomes the xz plane, and the second light emitting element 12 is arranged so that the polarization plane becomes the yz plane.

In this embodiment, since there is only one light receiving element, the first and second light emitting elements 11 and 12 are turned on alternately. Then, the output ratio (i90 / i0) of the light receiving element 2 in each case when the first light emitting element 11 is turned on and when the second light emitting element 12 is turned on is calculated by the calculation unit 4a.
Smoke can be identified by calculating with.
In this embodiment, the first light receiving element 11 is rotated by a motor or the like so that the polarization plane is the same as that of the second light emitting element 12, and the light receiving element 2 alternately receives the polarized light. Of course, smoke may be identified.

FIG. 9 shows a fourth embodiment. In this embodiment, one light emitting element 11, one light receiving element 21 and a polarization filter 31, and the light emitting element 11 and the polarization filter 3 are provided.
It is composed of driving means 51, 52 for rotating the 1. In this embodiment, the polarized light of the light emitting element 11 and the polarized light of the polarization filter 31 are rotated in synchronization with each other so that the directions of the polarization planes thereof are the same.

That is, as shown in FIG. 9A, first, the light emitting element 11 is stopped at a position where polarized light perpendicular to the scattering surface 41 is emitted from the light emitting element 11. At the same time, the polarization filter 31 is stopped at a position where its polarization plane is perpendicular to the scattering surface 41. Then, the light receiving element 21 receives the scattered light at that time. Next, by the driving means 51, FIG.
As shown in, the light emitting element 11 is rotated to a position where the polarized light is parallel to the scattering surface 41. At the same time, the polarization filter 31 is also rotated so that its polarization plane is parallel to the scattering surface 41, and the scattered light at that time is received by the light receiving element 21. Then, the smoke is identified by taking the ratio of the amount of received light in the above case and the amount of received light in this case. With such a configuration, smoke can be identified by one light emitting element and one light receiving element.

[0054]

As described above, according to the present invention, the ratio between the amount of polarized light received parallel to the scattering surface and the amount of polarized light received perpendicularly to the scattering surface is correlated with the type of smoke. Based on this, the reference value of the preset ratio is compared according to the detected smoke, and it is judged whether or not there is a fire depending on the type of smoke. Can be detected according to.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of an embodiment of a fire alarm device according to the present invention.

FIG. 2 is an explanatory diagram showing a relationship between an incident polarization plane and a polarization plane of a polarization filter in FIG.

FIG. 3 is an explanatory diagram showing smoke scattering efficiency when the filter paper is smoked.

FIG. 4 is an explanatory diagram showing smoke scattering efficiency when kerosene burns.

FIG. 5 is an explanatory diagram showing the scattering efficiency of cigarette smoke.

FIG. 6 is an explanatory diagram showing smoke identification parameters for each type of smoke.

FIG. 7 is a configuration diagram showing an optical system of a fire alarm device according to a second embodiment.

FIG. 8 is a configuration diagram showing a main part of a fire alarm device according to a third embodiment.

FIG. 9 is a configuration diagram showing a configuration of a fire alarm device according to a fourth embodiment.

FIG. 10 is a configuration diagram showing a main part of a scattered light type fire alarm device of a conventional example.

[Explanation of symbols]

 1: Light emitting element 2: Light receiving element 3: Polarization filter 4: Calculation section 5: Smoke type identification reference value setting section 6: Judgment section 11: First light emitting element 12: Second light emitting element 21: First light receiving Element 22: Second light receiving element 31: First polarization filter 32: Second polarization filter 41: First scattering surface 42: Second scattering surface 51, 52: Driving means

Claims (14)

[Claims] 1. A light emitting means for irradiating a smoke detection space with light and a light receiving means for receiving scattered light due to smoke are provided, and the amount of light received by the light receiving means is compared with a predetermined reference value to detect a fire. In the fire alarm device for determining the presence or absence, the light emitting means is a plane polarized light parallel to a scattering surface defined by the optical axis of the light emitting means and the optical axis of the light receiving means intersecting in the smoke inspection space. Outputting plane polarized light perpendicular to the light, the light receiving unit receives polarized light parallel to the scattering surface and polarized light perpendicular to the scattering surface, and further detects the amount of each polarized light received by the light receiving unit. Converting means, calculating means for calculating the ratio of the amount of received light of polarized light parallel to the scattering surface and polarized light converted by the photoelectric conversion means, and the ratio and smoke obtained by the calculating means. Based on the ratio preset for each type Fire alarm device compares the values, characterized in that a determination means for determining the presence or absence of fire for each type of smoke based on the reference value. 2. The fire alarm device according to claim 1, wherein the light emitting means is formed of a first light emitting element and a second light emitting element, and the light receiving means is a first light receiving element. And a second light receiving element, wherein the first light emitting element is arranged in the smoke inspection space by intersecting an optical axis of the first light emitting element and an optical axis of the first light receiving element. The plane-polarized light parallel to the defined first scattering surface is output, and the second light-emitting element is configured such that the optical axis of the second light-emitting element and the optical axis of the second light-receiving element intersect with each other. The plane polarized light perpendicular to the second scattering surface defined in the smoke detection space is output, the first light receiving element receives polarized light parallel to the first scattering surface, and the second light receiving element receives the polarized light parallel to the first scattering surface. The light-receiving element receives the polarized light perpendicular to the second scattering surface, and the photoelectric conversion means further comprises: Detecting the amount of light received by the first and second light receiving elements, and calculating the ratio of the amounts of light received by the first and second light receiving elements converted by the photoelectric conversion means. Fire alarm device. 3. The fire alarm device according to claim 1, wherein the light receiving means is formed of a first light receiving element and a second light receiving element, and the light emitting means emits light from the light emitting means. The plane and the optical axis of the first light receiving element intersect to output plane-polarized light parallel to the first scattering surface defined in the smoke inspection space, and the first light receiving element is the first light receiving element. The second light receiving element is defined in the smoke inspection space by intersecting the optical axis of the light emitting means with the optical axis of the second light receiving element. Polarized light perpendicular to the second scattering surface is received, the first scattering surface and the second scattering surface have a positional relationship perpendicular to each other, and the photoelectric conversion means includes the first and second scattering surfaces. Detecting the amount of light received by the light receiving element, and the calculation means is converted by the photoelectric conversion means. A fire alarm device, characterized in that a ratio of received light amounts of the first and second light receiving elements is calculated. 4. The fire alarm device according to claim 1, wherein the light emitting means includes a first light emitting element and a second light emitting element which are alternately turned on, and the first light emitting element. The element outputs plane-polarized light parallel to a first scattering surface defined in the smoke detection space by intersecting an optical axis of the first light emitting element and an optical axis of the light receiving means, The second light emitting element outputs plane-polarized light perpendicular to the second scattering surface defined in the smoke detection space due to the optical axis of the second light emitting element and the optical axis of the light receiving means intersecting with each other. The light receiving unit receives polarized light parallel to the first scattering surface, and the photoelectric conversion unit determines the amount of light received in each of the light receiving units when the first and second light emitting elements are turned on. The first light emission detected by the calculation means is converted by the photoelectric conversion means. Fire alarm device, characterized by calculating the ratio of the amount of light received at the light receiving quantity and the second light-emitting element is lit when the child lighting. 5. The fire alarm device according to claim 1, wherein the light emitting means outputs plane-polarized light, and the plane-polarized light is at a position perpendicular or parallel to the scattering surface. A driving means for rotating the light emitting means, and a polarizing filter disposed on the entire surface of the light receiving means and rotating in synchronization with the light emitting means at a position for transmitting only polarized light in the same direction as the plane polarized light. The photoelectric conversion means detects the amount of received light in each case of the light receiving means at a position where the plane polarized light output from the light emitting means is vertical and parallel to the scattering surface, and the arithmetic means is It is characterized in that the ratio of the received light amount at the position where the plane polarized light converted by the photoelectric conversion means is perpendicular to the scattering surface and the received light amount at the position where the plane polarized light is parallel to the scattering surface is calculated. Fire news Apparatus. 6. A light emitting means for irradiating light toward the smoke inspection space and a light receiving means for receiving scattered light due to smoke are provided, and the amount of light received by the light receiving means is compared with a predetermined reference value to detect a fire. In the fire detection method for determining the presence or absence, a plane polarized light parallel to a scattering surface defined by the light emitting means intersecting the optical axis of the light emitting means and the optical axis of the light receiving means in the smoke inspection space. Outputting plane polarized light perpendicular to the light, by the light receiving means, receives polarized light parallel to the scattering surface and polarized light perpendicular to, and detects the amount of each polarized light received by the light receiving means, The ratio of the amount of light received between the polarized light parallel to the scattering surface and the polarized light perpendicular to the scattering surface is calculated, the ratio is compared with a reference value of the ratio preset for each type of smoke, and based on the reference value Characterized by determining the presence or absence of fire for each type of smoke Fire detection method that. 7. The fire detecting method according to claim 6, wherein the light emitting means is formed of a first light emitting element and a second light emitting element, and the light receiving means is a first light receiving element. And a second light receiving element, wherein the first light emitting element intersects an optical axis of the first light emitting element and an optical axis of the first light receiving element in the smoke inspection space. By outputting plane-polarized light parallel to the defined first scattering surface, the optical axis of the second light emitting element intersects with the optical axis of the second light receiving element from the second light emitting element. Plane polarized light perpendicular to a second scattering surface defined in the smoke detection space is output, and polarized light parallel to the first scattering surface is received by the first light receiving element; The light receiving element receives the polarized light perpendicular to the second scattering surface, and the first and second Detecting the amount of light received by the second light receiving element, calculating the ratio of the amount of light received by the first and second light receiving elements, and determining the presence or absence of a fire for each of the ratio and the type of smoke. Method. 8. The fire detecting method according to claim 6, wherein the light receiving means is formed of a first light receiving element and a second light receiving element, and the light emitting means emits light from the light emitting means. The plane and the optical axis of the first light receiving element intersect to output plane-polarized light parallel to the first scattering surface defined in the smoke inspection space, and the first light receiving element causes the first light receiving element to output the plane polarized light. Polarized light parallel to the scattering surface of No. 1 is received, and is defined in the smoke inspection space by intersecting the optical axis of the light emitting means with the optical axis of the second light receiving element by the second light receiving element. Polarized light perpendicular to the second scattering surface is received, and the first scattering surface and the second scattering surface have a positional relationship perpendicular to each other, and the amount of light received by the first and second light receiving elements. Is detected, the ratio of the amount of light received by the first and second light receiving elements is calculated, and the ratio is calculated. Fire detection method characterized by comparing a reference value preset the ratio for each type of smoke, determining the presence or absence of fire for each type of smoke based on the reference value. 9. The fire detection method according to claim 6, wherein the light emitting means is formed of first light emitting elements and second light emitting elements that are alternately turned on, and the first light emitting element is used. The element outputs plane-polarized light parallel to a first scattering surface defined in the smoke inspection space by intersecting an optical axis of the first light emitting element and an optical axis of the light receiving means, The second light emitting element outputs plane-polarized light perpendicular to the second scattering surface defined in the smoke inspection space by intersecting the optical axis of the second light emitting element and the optical axis of the light receiving means. , The polarized light parallel to the first scattering surface is received by the light receiving means, and the first scattering surface and the second scattering surface have a positional relationship perpendicular to each other, and the first and second The ratio of the amount of light received when the second light emitting element is lit and the amount of light received when the second light emitting element is lit Calculated and is compared with the reference value preset the ratio for each type of said ratio and smoke, fire detection method characterized by determining the presence or absence of fire for each type of smoke based on the reference value. 10. The fire detecting method according to claim 6, wherein the light emitting means outputs plane-polarized light, and the plane-polarized light is at a position perpendicular or parallel to the scattering surface. A driving means for rotating the light receiving means, and a polarization filter disposed on the entire surface of the light receiving means and rotating in synchronization with the light emitting means at a position for transmitting only polarized light in the same direction as the plane polarized light, A position where the plane polarized light is perpendicular to the scattering surface while detecting the amount of light received by the light receiving means in each position where the plane polarized light output from the light emitting means is perpendicular and parallel to the scattering surface. The ratio of the received light amount at and the received light amount at the position where the plane polarized light is parallel to the scattering surface is calculated, and the ratio is compared with a reference value of the ratio preset for each type of smoke, Fire for each type of smoke based on the standard value A fire detection method characterized by determining the presence or absence of a disaster. 11. The fire alarm device according to any one of claims 1 to 5, wherein the scattering angle is 60 ° to 140 °. 12. The fire alarm system according to any one of claims 1 to 5, wherein the scattering angle is 90 °. 13. The fire detection method according to claim 1, wherein the scattering angle is 60 ° to 140 °. 14. The fire detection method according to claim 1, wherein the scattering angle is 90 °.