JPS63151827A - Fire judge apparatus - Google Patents

Abstract

PURPOSE:To accurately judge a fire by enhancing the judge reliability of the fire based on the flickering frequency of a flame, by judging the fire when the timewise change of the flickering frequency of the detected flame shows a reducing tendency. CONSTITUTION:A flame detector 1 is constituted so that the flame 3 due to a fire generated in a warning area is formed into an image on a light receiving surface by an optical system 2 such as a condensing lens and the electric signal corresponding to the light energy from the flame 3 is outputted. The detection output from the flame detector 1 is given to a flickering frequency detection part 4 to detect, for example, the flickering frequency of the flame becoming 10Hz or less. Next, the flickering frequency of the detected flame is given to a frequency change judge part 5. The frequency change judge part 5 monitors, for example, the timewise change in the flickering frequency of 10Hz or less judged to be a fire and generates judge output to a fire judge part 6 when judges the timewise change wherein the flickering frequency becomes a reducing tendency. By this method, the judge reliability of the fire is enhanced and the fire can be accurately judge.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fire determination device that determines whether there is a fire based on the flickering frequency of flames in the event of a fire.

(Prior Art) Conventionally, in a device that detects light energy emitted from flames to determine a fire, the flickering frequency of flames during a fire is generally in the range of 18Z to 10H2. It is determined that there is a fire when a certain flickering frequency is obtained.

(Problems to be Solved by the Invention) However, in such conventional fire judgment based only on the flickering frequency of the flame, the flickering frequency of the non-fire flame, such as on a gas stove where the size of the flame does not change, is When a fire occurs within a specific fire judgment range, there is a risk that an incorrect fire judgment will be made.

(Means for Solving the Problems) The present invention has been made in view of these conventional problems, and aims to further improve the reliability of fire judgments based on the flickering frequency of flames, thereby enabling accurate fire judgments. The purpose of the present invention is to provide a fire detection device that enables fire detection.

In order to achieve this objective, the present invention focuses on the fact that the flickering frequency of the flame obtained through fire experiments causes a frequency change that decreases as the flame spreads over time from the occurrence of the fire. A fire determining means is provided which determines that a fire has occurred when the temporal change in the flickering frequency of the flame detected by the frequency detecting means shows a decreasing tendency based on the detection output of the flame detecting means.

(Function) According to the configuration of the present invention, the flickering frequency of the flame detection signal obtained from the flame detection means that converts the light energy of the flame into an electric signal will change as the flame spreads in the case of a fire. For example, the flicker frequency decreases over time in the range of 10 Hz or less, which was previously considered to be a fire.
By detecting this decreasing trend in flicker frequency, it is possible to accurately determine the presence of a fire.

(Example) FIG. 1 is a block diagram showing one embodiment of the present invention.

First, to explain the configuration, 1 is a flame detector, which uses an optical system 2 such as a condensing lens to form an image of flame 3 caused by a fire occurring in a restricted area on a light receiving surface, and generates electricity according to the light energy from the flame 3. Outputs a signal (flame detection signal).

The detection output from the flame detector 1 is given to a flicker frequency detection section 4, which detects a flickering frequency component of the flame that is, for example, 10H2 or less. As the flicker frequency detection section 4, a frequency analyzer that detects a frequency component consisting of fluctuations in the amplitude of the flame detection signal or a frequency filter that extracts a frequency component of 10H2 or less that is determined to be a fire is used.

The flicker frequency of the flame detected by the flicker frequency detection section 4 is given to the frequency change determination section 5.

The frequency change determination unit 5 monitors the temporal change in the flicker frequency of 10 Hz or less, which is determined to be a fire, for example, and generates a determination output to the fire determination unit 6 when determining a time change in which the flickering frequency tends to decrease.

On the other hand, in this embodiment, in order to judge a fire based on the level of the flame detection signal obtained from the flame detector 1, that is, the size of the flame 3, the fire level detection section 7 and the level judgment section 8 are arranged in parallel. The fire level detection section 7 detects the amplitude peak level of the flame detection signal, and the level discrimination section 8 outputs a judgment output when the amplitude peak value exceeds a predetermined threshold level. I try to give it to As the fire determining means based on the flame level, which is composed of the flame level detecting section 7 and the level determining section 8, for example, the one already proposed in Japanese Patent Application Laid-open No. 178621/1988 may be used.

Therefore, when the fire determination section 6 receives the determination output from either the frequency change determination section 5 or the level determination section 8,
Alternatively, when both determination outputs are obtained, a fire detection signal is output.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

Figure 2 is a graph showing the temporal change in flame flickering frequency obtained in a fire experiment in which wood was burned. In other words, as the flame expands, the flickering frequency shifts to a lower level, and when the flame reaches around 1 m (approximately 5 minutes), a stable combustion state is reached, and the flickering frequency at that time settles down to approximately 2 to 4 Hz. .

The tendency for the flickering frequency to decrease over time obtained through fire experiments is almost the same in actual fires, and in the embodiment shown in FIG. A flickering frequency component is detected by the flickering frequency detection section 4, and a time change of this flickering frequency component is monitored by a frequency change determining section 5. When the flickering frequency component shows a decreasing tendency with the passage of time, an actual fire is detected. It is judged that there is a flame, and a judgment output is generated in the fire judgment section 6.

On the other hand, for non-fire flames such as gas stoves, the size of the flame does not change over time, so the flickering frequency from non-fire flames is determined to be a fire.
Even if it has a flickering frequency component below H2,
There is no tendency for the flickering frequency component to decrease over time, and an erroneous fire judgment output will not occur.

On the other hand, in an actual fire, the time from ignition to the spread of the flame is expected to be very short, as in the case of a fire in a kerosene stove, etc., and in this case, the decrease in flicker frequency will be instantaneous. Therefore, it may not be possible to capture the decreasing change in the flickering frequency component. Therefore, in the embodiment shown in FIG. 1, a means for determining a fire from the flame level by the fire level detection section 7 and the level determination section 8 is separately provided, and when the flame detection level exceeds a predetermined threshold level, , so that a fire judgment output can be obtained immediately.

(Effects of the Invention) As described above, according to the present invention, the light energy emitted from the flame during a fire is detected by the flame detection means, and the flickering frequency of the flame is detected based on the detection output of the flame detection means. However, since we have provided a means to determine that there is a fire when the temporal change in the detected flicker frequency shows a decreasing trend, it is possible to make accurate fire judgments by detecting the spread of flames from the decreasing trend in the flickering frequency. , the reliability of fire judgment based on flame flickering frequency can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a graph showing changes in flame flickering frequency over time. 1: Flame detector 2: Optical system 3: Flame 4: Flickering frequency detection section 5: Frequency change judgment section 6: Fire judgment section 7: Flame level detection section 8 Two-level judgment section

Claims (1)

[Claims] flame detection means for converting light energy emitted from flames into electrical signals during a fire; frequency detection means for detecting a flickering frequency of the flame based on a detection output from the flame detection means; and flickering detected by the frequency detection means. 1. A fire determination device comprising a determination means for determining a fire by detecting a decreasing tendency of frequency.