JPS63204398A - Radiant type fire detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) This invention relates to a radiation-type fire detector that detects radiant light emitted from a flame to notify a fire.

(Prior art) Conventionally, radiation fire detectors detect two different spectral components in infrared rays, and by comparing their radiation amounts, they can distinguish between flames, sunlight, or light such as lighting (hereinafter referred to as environmental light). A two-wavelength fire detector that distinguishes the However, there is a risk of malfunction due to the blue rotating lights of cars, etc., so in order to avoid this, the range in which long wavelength spectral components are detected has been shifted to a range that does not include these components. For this purpose, a pyroelectric element was used as the element. Under normal ambient light, its output is in the short wavelength spectrum > long wavelength spectrum, but in the case of radiant light from a flame, the output is in the short wavelength spectrum. The wavelength spectrum changes to a long wavelength spectrum, and this reversal was detected to notify the occurrence of a fire.

<Problems with the conventional technology> Detectors using pyroelectric elements are excellent in that they do not malfunction due to rotating blue lights, etc., but noise output occurs due to changes in ambient temperature, shock, or deterioration. However, there were cases where the above output relationship was reversed and a fire alarm was issued even though there was no fire.

Means for Solving the Problems> In view of the drawbacks of the conventional fire detectors mentioned above, the present invention provides a radiation type fire detection system that is less likely to malfunction even when a pyroelectric element is used as an element for detecting long wavelength spectral components. The purpose of this technology is to detect the short-wavelength spectral component and long-wavelength spectral component of the radiant light emitted from the flame using solar cells and pyroelectric elements, respectively, and to detect the short wavelength spectral component and the long-wavelength spectral component of the radiant light emitted from the flame. In a radiation type fire detector that emits a fire signal when the wavelength spectrum component changes from a long wavelength spectrum component to a short wavelength spectrum component (long wavelength spectrum component),
The long wavelength spectral component of the radiant light is detected simultaneously using two pyroelectric elements, and a fire signal is generated when the smaller of the outputs obtained is larger than the output of the short wavelength spectral component obtained through the solar cell. It is designed to emit.

(Function) In the case of a fire, the fire detector configured as above will:
Out of the outputs from the two pyroelectric elements, the output from the smaller one also becomes larger than the output from the solar cell, which causes a fire signal to be issued. In addition, if one of the two pyroelectric elements is normal and the output of the other pyroelectric element deteriorates and produces an output similar to that in a fire, the output from the normal pyroelectric element will be lower than that of the solar cell. Since the output is compared with the output of , the relationship of short wavelength spectral component > long wavelength spectral component under normal conditions is maintained and no fire signal is emitted.

(Example) In Figure 0, which describes an example of the radiation fire detector of the present invention using drawings, 11.12 transmits the long wavelength spectrum 1.0 to 2.2 μm of flame radiated from the same location. Similarly, the filter 13 has a short wavelength spectrum of 0.
A filter that transmits light of 8 to 1.0 μm, 21.22 is a pyroelectric element, and is provided corresponding to the filters 11 and 12.

A solar cell 23 is provided corresponding to the filter 13.

31, 32, and 33 are AC amplifiers, respectively, and the pyroelectric element 2
Among the alternating current outputs generated at the output resistor R7 provided corresponding to the solar cell 23 and the solar cell 23, the alternating current output of 3 Hz to 20 Hz input through the resistor R8 and the capacitor CI is amplified. 41, 42, and 43 are smoothing circuits, respectively, which are provided corresponding to amplifiers 31, 32, and 33, and are series circuits of resistors R1 and R1 connected in parallel between signal line connection terminals P and P' that also serve as power supply. , a rectifying diode D connected to the connection point thereof, and a resistor R connected between this and the terminal P° and having a resistor R3 and a capacitor C1 in parallel, and an amplifier 31.゜32,
33 through a capacitor C1.

51 and 52 are comparators, of which comparator 51 is provided to detect the magnitude relationship of the outputs from the pyroelectric elements 21 and 22, the in-phase input is connected to the output of the smoothing circuit 41, and the non-in-phase input is connected to the smoothing circuit 41. are connected to the outputs of circuit 42, respectively. on the other hand,
The comparator 52 is provided to detect the magnitude relationship between the long wavelength spectral component and the short wavelength spectral component, and its in-phase input is connected to the smoothing circuit 41 through the analog switch SWl and to the smoothing circuit 42 through the analog switch SW2. , the control input of the analog switch SW1 is connected through the inverter INV, and that of SW2 is directly connected to the output of the comparator 51. Further, the non-in-phase input of the comparator 52 is connected to the output of the smoothing circuit 43.

Reference numeral 6 is an integrating circuit, which is provided to prevent malfunction due to electrical noise, etc., and is connected to a charging resistor R? and capacitor C
It consists of 4.

Reference numeral 7 denotes a switching circuit, which is composed of a PUT (TI), a transistor T, and a resistor, and is connected to a light emitting diode L as a fire indicator.

Next, the operation of the radiation type fire detector will be explained.

While the detector is irradiated with environmental light such as sunlight or illumination, a size relationship occurs between the pyroelectric elements 21 and 22 even if they receive the same light, and the spectral components of these lights are
The relationship is short wavelength spectral component>long wavelength spectral component. That is, the outputs of the pyroelectric elements 21, 22 and the solar cell 23 are amplified by amplifiers 31, 32, and 33, respectively, and smoothed by smoothing circuits 41, 42, and 43. Then, the outputs of the smoothing circuits 41 and 42 are compared by a comparator 51, and for example,
When the output of the smoothing circuit 41 is smaller than the output of the smoothing circuit 42, the comparator 51 is at a low level, and the inverter I
Analog switch SW1 is closed via NV and SW2
will be held. Here, the output relationship between the smoothing circuits 41 and 43 is that the output of the smoothing circuit 43>the output of the smoothing circuit 41, so the comparator 52 maintains the low level. Therefore, the integrating circuit 6
The switching circuit 7 does not operate, and the light emitting diode L as a fire indicator light is not lit.

When a fire detector is irradiated with radiant light from the flames caused by a fire, a relationship in output magnitude occurs between the pyroelectric elements 21 and 22 as in the case described above, but unlike in the case of ambient light, Wavelength spectral component>Short wavelength spectral component 0 For example, if the output of the smoothing circuit 41 is larger than the output of the smoothing circuit 42, the comparator 51 becomes high level, the analog switch SW2 is closed, and the SWI is opened.

Here, the output relationship between the smoothing circuits 42 and 43 is as follows:
Since the output becomes the output of the smoothing circuit 42, the comparator 52 is inverted to high level. As a result, the switching circuit 7 is turned on after a predetermined time through the integrating circuit 6, and the terminals P and
P' is almost short-circuited, a fire signal is sent to a receiver (not shown), and a light emitting diode L is turned on as a fire indicator light.

On the other hand, if any of the pyroelectric elements 21 and 22, for example 21, generates a noise output similar to that when flame is irradiated due to deterioration, the comparator 51 becomes high level as in the case of the fire explanation above. . This allows analog switch SW
2 is closed, and the comparator 52 compares the output of the smoothing circuit 42 and the output of the smoothing circuit 43. However, the output of the smoothing circuit 42, which smoothes the output from the normal pyroelectric element 22, is <It becomes the output of the smoothing circuit 43, and the comparator 5
2 maintains the low level. Therefore, the integrating circuit 6 and the switching circuit 7 are not operated, and the light emitting diode L is not lit.

(Effects) The radiation type fire detector of this invention is a radiation type fire detector that does not malfunction even if one of the pyroelectric elements used therein generates an output similar to that of a fire due to deterioration etc. There is an effect that can be obtained.

[Brief explanation of the drawing]

The drawing is a circuit diagram of an embodiment of the radiation type fire detector of the present invention. 21, 22... Pyroelectric element, 23... Solar cell, 31
．． 32゜33... AC amplifier, 41.42.43...
・Smoothing circuit, 51°52... Comparator, 6... Integrating circuit, 7... Switching circuit, SWI, SW2...
Analog switch, ■NV...Inverter. Patent applicant Jin Nomi JJ Jin Kogyo Co., Ltd.

Claims (1)

[Claims] The short wavelength spectral component and the long wavelength spectral component of the radiant light emitted from the flame are detected by a solar cell and a pyroelectric element, respectively, and the output relationship between the two components is as follows: short wavelength spectral component > long wavelength spectral component to short wavelength. In a radiation-type fire detector that emits a fire signal when the spectral component < long wavelength spectral component, the long wavelength spectral component of the radiant light is simultaneously detected by two pyroelectric elements, and the one with the smaller output is detected. A radiation type fire detector characterized in that a fire signal is emitted when the output becomes larger than the output of short wavelength spectral components obtained through a solar cell.