JP5183553B2 - Fire detector - Google Patents

Description

  The present invention relates to a fire detector, and more particularly to a fire detector that monitors a wide range by swiveling.

  Conventionally, there has been a fire detector in which an ultraviolet sensor and an infrared sensor are provided side by side in a casing so that the same direction of the monitoring range can be monitored, and a wide range is monitored by turning the casing over a predetermined range. . This fire detector first turns the casing in the horizontal direction, and when the ultraviolet sensor detects a fire source candidate, stops the turning of the casing at that time. Next, the infrared sensor is operated in a state where the ultraviolet sensor faces the direction in which the fire source candidate is detected. And if an infrared sensor detects a predetermined amount of infrared rays during a fixed time, it will be judged that there is a fire source in the direction (for example, refer to patent documents 1).

  By the way, when comparing the ultraviolet sensor and the infrared sensor, the ultraviolet sensor has a faster response speed to the fire source due to the characteristics of the sensor. Therefore, when turning both sensors at the same speed, if the turning speed is made to correspond to the response speed of the ultraviolet sensor and turn faster, the response speed of the infrared sensor cannot catch up and the fire source cannot be detected accurately by the infrared sensor. .

JP 2006-338419 A

  For this reason, in a conventional fire detector, an infrared sensor first detects a fire source candidate existing in the monitoring range with an ultraviolet sensor, and determines whether the fire source candidate detected by the ultraviolet sensor is a real fire. A two-stage processing operation, which is a judgment stage, is required, and it takes time to detect the fire source.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a fire detector that detects a fire source within a monitoring range at an early stage.

  The fire detector according to the present invention includes an ultraviolet sensor and an infrared sensor having sensitivity in a specific band, and rotates around a rotation axis to monitor a monitoring range. The ultraviolet sensor and the infrared sensor are The horizontal viewing angle of the infrared sensor is set wider than the horizontal viewing angle of the ultraviolet sensor.

  According to the fire detector of the present invention, the horizontal viewing angle of the infrared sensor, that is, the viewing angle in the turning direction is set wider than the horizontal viewing angle of the ultraviolet sensor. For this reason, it is possible to turn the infrared sensor at a fast turning speed that matches the response speed of the UV sensor, and it is possible to accurately detect the fire source in the monitoring range even at a fast turning speed, thus detecting the fire source early. There is an effect that can be done.

It is a block diagram which shows the structure of the fire detector which concerns on embodiment of this invention. It is a conceptual diagram which shows the mode in a housing | casing. It is sectional drawing which shows the structure of the infrared sensor of a fire detector. It is a top view which shows the mode of the visual field of an infrared sensor and an ultraviolet sensor. It is the top view which showed the state which rotated the fire detector horizontally with respect to the monitoring range. It is the figure which showed simply the output state from the ultraviolet sensor 2 and the infrared sensors 1a and 1b in which the turning angle of FIG. 5 is between 90 degrees and 100 degrees.

An embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the case 4 of the fire detector S includes infrared sensors 1 a and 1 b, an ultraviolet sensor 2, and a detection unit 3. The housing 4 is fixed to the rotation shaft 5, and the rotation shaft 5 is rotated by the turning device 6, so that the housing 4 is turned over a predetermined range. The turning angle of the housing 4 is measured by an angle sensor 7 provided in the turning device 6.

  As shown in FIG. 1, the infrared sensors 1 a and 1 b and the ultraviolet sensor 2 are fixed on the center line C of the fire detector S in a line in the vertical direction on the housing 4. As shown in FIG. 3, the infrared sensors 1 a and 1 b partially block infrared rays incident on the infrared detection element 9, the band-pass filter 10 disposed on the front surface of the infrared detection element 9, and the infrared detection element 9. A field-of-view restriction unit 11 that determines an angle and a signal line 12 that outputs an output signal from the infrared detection element 9 are provided.

  The infrared sensors 1a and 1b have sensitivity in different specific bands. For example, in the infrared sensor 1a, sapphire is used as the bandpass filter 10, and for example, infrared rays in a frequency band centered on 4.4 μm are detected. Further, in the infrared sensor 1b, germanium is used as the bandpass filter 10, and for example, infrared rays in a frequency band centered on 3.9 μm are detected.

  The viewing angle of the infrared sensors 1a and 1b in the horizontal direction, that is, the direction of turning, is limited to, for example, 10 degrees by the field limiting unit 11. The viewing angle referred to here means a range of angles at which light from the outside is incident on the infrared sensors 1a and 1b. In this embodiment, the viewing angle of the infrared sensors 1a and 1b is 10 degrees. However, this value may be appropriately determined within the range of 1 to 100 degrees.

  As shown in FIG. 1, the ultraviolet sensor 2 is fixed to the housing 4 like the infrared sensors 1a and 1b, and further, for example, eight ultraviolet detections arranged in a line on the front surface so as to be in contact with the vertical direction. It has the element 8. The ultraviolet detection element 8 has sensitivity in a specific band, for example, an ultraviolet band of 150 nm to 260 nm.

The viewing angle of the ultraviolet detection element 8 in the horizontal direction, that is, the turning direction, is set to, for example, 1 degree by the viewing restriction unit 11 (not shown) like the infrared sensors 1a and 1b. In the above example, the viewing angle in the horizontal direction of the ultraviolet sensor 2 is 1 degree, but this value may be appropriately determined within the range of 0.1 to 10 degrees.
In this embodiment, the viewing angles of the infrared sensors 1a and 1b and the ultraviolet sensor 2 are limited by the visual field limiter 11. However, an optical system such as a lens is provided in front of the infrared sensors 1a and 1b and the ultraviolet sensor 2. A predetermined viewing angle may be obtained.

  The ratio of the viewing angle in the horizontal direction between the ultraviolet sensor 2 and the infrared sensors 1a and 1b is 1:10. The viewing angle ratio is 1: 1.1 to 1: 100, preferably 1: 5 to 1:20.

FIG. 4 is a plan view showing the field of view of the ultraviolet sensor 2 and the infrared sensors 1a and 1b.
The field of view U of the ultraviolet sensor 2 is fan-shaped with the fire detector S as a vertex, and the viewing angle α is 1 degree. On the other hand, the visual fields Ia and Ib of the infrared sensors 1a and 1b spread in a fan shape with the fire detector S as an apex, and the viewing angle β is 10 degrees, which is set wider than the viewing angle α of the ultraviolet sensor 2. As shown in FIG. 4, the visual field U of the ultraviolet sensor 2 and the visual fields Ia and Ib of the infrared sensors 1a and 1b overlap.

More specifically, as shown in FIG. 1, the infrared sensors 1a and 1b are on the center line C of the fire detector S and are fixed to the casing 4 in a line in the vertical direction. The visual fields Ia and Ib of 1a and 1b completely overlap.
Further, since the ultraviolet sensor 2 and the infrared sensors 1a and 1b are also fixed to the casing 4 in a line in the vertical direction, the visual field U of the ultraviolet sensor 2 and the visual fields Ia and Ib of the infrared sensors 1a and 1b overlap. Specifically, the bisector (center line) of the viewing angle β of the infrared sensors 1a and 1b and the bisector (center line) of the viewing angle α of the ultraviolet sensor 2 are respectively the center lines of the fire detector S. It is provided so as to overlap with C.

Next, the configuration of the detection unit 3 will be described with reference to FIG.
The detection unit 3 includes an amplifier 15 that amplifies the analog outputs of the infrared sensors 1a and 1b and the ultraviolet sensor 2, an A / D converter 16 that converts the amplified analog output into a digital output, and a predetermined period for the output of each sensor. And MPU 17 for judging whether the position of the fire source candidate and whether the fire source candidate is a real fire.

Next, the operation of the present invention will be described.
FIG. 5 is a plan view showing a state in which the fire detector S is horizontally swiveled with respect to the monitoring range E. When the fire detector S is swung, the field of view Ia of each sensor 1a, 1b, 2 over time is shown. , Ib, U states. The monitoring range E is a range from 0 degrees to 180 degrees with the fire detector S as the center. For example, the range is swung at a turning speed of 10 degrees per second, and the turning of 180 degrees is performed over 18 seconds. The case of performing will be described.
As an example, it is indicated that the fire source F exists when the turning angle r is between 90 degrees and 100 degrees. Here, the turning angle r is an angle indicating how much the fire detector S is turning from 0 degree with reference to 0 degree. The value is detected by the angle sensor 7 and the fire source F It is used as information for determining the location of

FIG. 6 simply shows the output state from the ultraviolet sensor 2 and the infrared sensors 1a and 1b when the turning angle r in FIG. 5 is between 90 degrees and 100 degrees, and FIG. 2 and FIG. 6B are the outputs of the infrared sensors 1a and 1b.
The outputs of the sensors 1a, 1b, and 2 are captured at a predetermined cycle by the detection unit 3 and compared with a preset threshold value. If it is equal to or greater than the predetermined threshold, the output is shown in black.

  Here, the sampling frequency of the ultraviolet sensor 2 is set to 40 Hz, and the sampling frequency of the infrared sensor is set to 4 Hz. Accordingly, when the turning angle r is between 90 degrees and 100 degrees, the turning speed is 10 degrees / sec. Therefore, the turning is possible in one second, and in the case of the above-described sampling frequency, The ultraviolet sensor 2 can capture a signal 40 times, and the infrared sensors 1a and 1b can capture a signal 4 times.

  The output diagram obtained from each sensor shown in FIG. 6 is largely related to the turning speed and the sampling frequency of each sensor. Even in the infrared sensors 1a and 1b having a low sampling frequency, the UV sensor can be obtained by reducing the turning speed. As in FIG. 2, a high-resolution output diagram in which the monitoring range E is closely monitored can be obtained. However, in such a case, it takes time to monitor the entire wide monitoring range E, and the fire source F cannot be detected at an early stage.

  Therefore, in this embodiment, the fire detector S is turned at a turning speed corresponding to the ultraviolet sensor 2. The “turning speed corresponding to the ultraviolet sensor 2” may be a turning speed at which the position of the fire source candidate can be specified sufficiently from the output diagram obtained from the ultraviolet sensor 2, and the ultraviolet sensor 2 whose sampling frequency is set high. If so, the turning speed can be increased accordingly.

  As shown in FIG. 6, since the infrared sensors 1a and 1b have a slow response speed and a low sampling frequency, the output is 4 times in the monitoring range E of 10 degrees and the output is 72 times in the monitoring range E of the entire 180 degrees. Can only get. In contrast, the ultraviolet sensor 2 can obtain 40 outputs in the monitoring range E of 10 degrees and 720 outputs in the monitoring range E of 180 degrees as a whole. That is, the ultraviolet sensor 2 can obtain a high-resolution output diagram, and can finely specify where the fire source candidate is in the monitoring range E. However, since the ultraviolet sensor 2 operates also by detecting ultraviolet rays other than the fire source F, it is determined whether the fire source candidate is a real fire based on the output diagram of the ultraviolet sensor 2 alone. Difficult to do.

  Therefore, in this embodiment, the infrared sensors 1a and 1b are used at the same time to determine whether or not the fire source candidate is a real fire. For example, let us consider a case where the viewing angle β of the infrared sensors 1a and 1b is the same as the viewing angle α of the ultraviolet sensor 2 and is a narrow monitoring viewing angle (1 degree). In this case, if the turning speed remains high due to the low sampling frequency, the output diagrams of the infrared sensors 1a and 1b are in a missing state and cannot cover the entire monitoring range E.

  Therefore, by setting the viewing angle β of the infrared sensors 1a and 1b to be wider than the viewing angle α of the ultraviolet sensor 2, even if the fire detector S turns faster at the turning speed corresponding to the ultraviolet sensor 2, the monitoring range E is sufficiently obtained. Can be covered. In this case, since the infrared sensors 1a and 1b have a low sampling frequency, only an output diagram with a coarse resolution can be obtained, but it can be determined whether or not there is a fire source candidate at an approximate position. Thus, the detection unit 3 calculates the logical product of the high resolution output diagram of the ultraviolet sensor 2 and the low resolution output diagrams of the infrared sensors 1a and 1b, thereby detecting the fire source F and its position in the monitoring range E. It becomes possible.

In FIG. 6A, the output of the ultraviolet sensor 2 detects ultraviolet rays of a predetermined threshold value or more at the “15” to “25” times in 40/40 seconds. In FIG. 6B, the infrared sensor detects infrared rays that are equal to or greater than a predetermined threshold at the “2” and “3” times in 4/4 seconds. When the detected fire source candidate is a real fire, the sensor output ratio when the infrared sensor of the embodiment is used is 3.9 μm <4.4 μm, which is an output ratio different from that of a general light source or high-temperature object. Is obtained. Therefore, by analyzing the ratio of these outputs, it is possible to determine that it is a real fire. From the above results, it is possible to determine that the fire source F exists at the place of the turning angle r corresponding to the sampling frequency of “15” to “25” times of the ultraviolet sensor 2, and from “15” to “ It can be determined that the 25th output is a real fire.
In addition, if the position of the fire source F can be specified, the water discharge range of the fire extinguisher separately provided may be determined as necessary, and the fire source F may be discharged.

In this embodiment, in order to determine that the detected fire source candidate is a real fire, the output ratio of the infrared sensors 1a and 1b is used. However, the output value of the ultraviolet sensor 2 may be used. .
In the present embodiment, the bisector (center line) of the viewing angle β of the infrared sensors 1a and 1b and the bisector (center line) of the viewing angle α of the ultraviolet sensor 2 are respectively set to the fire detector S. It is provided so as to overlap with the center line C, and the monitoring range of each sensor is provided in the same direction, but each sensor only needs to monitor the same monitoring range, and the center line of each sensor does not necessarily overlap. Good.

Since the present invention has a wider field of view in the turning direction of the infrared sensors 1a and 1b than the ultraviolet sensor 2, the infrared sensors 1a and 1b can be turned at a turning speed that matches the response speed of the ultraviolet sensor 2. The fire source F in the range E can be detected early.
Moreover, since the two types of infrared sensors 1a and 1b having different monitoring wavelengths are provided, it can be determined that the fire source candidate is a real fire more accurately.
Moreover, since the ultraviolet sensor 2 and the infrared sensors 1a and 1b are vertically arranged in a line and can be swung and scanned at the same speed in the same direction by one central axis, the mechanism of the fire detector can be simplified.

  S fire detector, 1a, 1b infrared sensor, 2 ultraviolet sensor, 3 detector, 4 housing, 5 rotating shaft, 6 swivel device, 7 angle sensor, C center line, 8 ultraviolet detector, 9 infrared detector, 10 Bandpass filter, 11 Field limiter, 12 Signal line, 15 Amplifier, 16 A / D converter, U Field of view of UV sensor 2, Ia, Ib Field of view of infrared sensors 1a, 1b, α Field of view of UV sensor 2, β Infrared sensor 1a, 1b viewing angle, X protection area, E monitoring range, W wall surface, F fire source.

Claims (3)

In a fire detector that has an ultraviolet sensor and an infrared sensor that have sensitivity in a specific band, rotates around a rotation axis, and monitors a monitoring range.
The fire is characterized in that the ultraviolet sensor and the infrared sensor are provided to face the same monitoring range, and the horizontal viewing angle of the infrared sensor is set wider than the horizontal viewing angle of the ultraviolet sensor. Detector.   The fire detector according to claim 1, wherein the infrared sensor includes two or more infrared sensors having sensitivity in different bands.   2. The fire detector according to claim 1, wherein the ultraviolet sensor and the infrared sensor are vertically arranged in a line and are turned at the same speed in the same direction.

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