JPH03171399A - Light-reducing separate type fire sensor - Google Patents

Abstract

PURPOSE:To surely detect a fire even in the case a light receiving unit receives light from a flame directly and light receiving quantity is increased by detecting the fire by catching the increased quantity of light by the light from the flame simultaneously in addition to the detection of the reduced quantity of light by smoke. CONSTITUTION:A light emitting unit 10 arranged so as to be opposed is provided with a light emitting element 12 to send modulation light. Besides, the light receiving unit 20 is provided with a light receiving element 21 to receive the modulation light and the light caused by the fire and convert them into an electric signal, a first filter 23 to pass a modulation signal component, a second filter 24 to pass a light signal component by the fire, a first comparison circuit 25 to detect that the passed signal of the filter 23 falls below a prescribed threshold, and a second comparison circuit 26 to detect that the passed signal of the filter 24 exceeds the prescribed threshold. Accordingly, the increased quantity of light by the light from the flame can be caught simultaneously in addition to the reduction of light by the smoke. Thus, even in the case the light from the flame is received and the light receiving quantity is increased, the fire can be surely detected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a dimming type that detects a fire from the attenuation of light due to smoke by arranging a light emitting unit (1) and a lighting unit (4) in a corner. Separate fire detector (.: related).

[Prior art] In the conventional dimming type separate smoke detector, the light emitting unit 1
・The light receiving unit 1 and the light receiving unit 1 and 2 are placed separately and facing each other, and a smoke detector set in the smoke detection space detects the decrease in light due to the intrusion of smoke and detects a fire. .

[Problems to be Solved by the Invention] However, conventional dimming-type separation fire detectors cannot effectively control fires such as smoldering fires that are difficult to ignite and produce a large amount of smoke. However, in the case of a fire that ignites without emitting much smoke and causes flames to rise, it is possible to detect light from the flames even though the light transmission is blocked by smoke. On the contrary, there was an increase of I7 in receiving light and 4 in misreporting.

The present invention has been made in view of the drawbacks of the conventional technology, and therefore, it is an object of the present invention to provide a dimming type separate fire detector that can reliably detect even a fire with little smoke and high flames. purpose.

[Means for Solving the Problems] To achieve this object, the present invention is configured as follows. Incidentally, the symbols in the drawings of the embodiments are also indicated.The O dimming type fire detector of the present invention has the light emitting units 1 and 10 and the light receiving units 1 and 20 in the smoke detection space. The light emitting unit 1.]0 is arranged to face the light emitting unit 1.
The light receiving unit 20 includes a light receiving element 12 which receives the modulated light and light generated by a fire and converts it into electric light. , the light receiving element 21. It is included in the Hengo Shingetsu, so let the Henki Shingetsu component pass through.
3, and the fire included in the conversion signal of the light receiving element 2, J,
The second filter 24 detects that the signal passing through the first filter 23 has decreased below a predetermined threshold;
The second comparison circuit 12 detects that the signal passing through the second filter 24 exceeds a predetermined threshold and outputs a fire detection signal.

[Function] According to the attenuation-type separate fire detector of the present invention having such a configuration, in addition to the dimming due to smoke, it is possible to simultaneously capture an increased scene due to light from the flame, and the light from the flame can be captured simultaneously. It is possible to reliably detect a fire even if the amount of light received increases.

[Embodiment 1] Fig. 1 is a construction diagram of an embodiment of the fence showing an embodiment of the present invention.

In FIG. 1, 10 is a light emitting unit, 20 is a light receiving unit 3, and as shown in FIG.
and the light receiver. Nits 1 and 20 are arranged facing each other with a smoke detection space 30 in between.

The light emitting unit 10 is provided with a modulation circuit 1j and a light emitting element 12, and a modulation circuit 1l outputs a variable signal 551 of a predetermined frequency f1.
1{i is intermittently output, and the light emitting element 12 is driven to emit light by this modulation signal, thereby emitting modulated light to the light receiving unit 20. As the light emitting element 12, for example, a light emitting LED is used.
Use.

The modulated light from the light emitting unit I-10 is passed through the optical filter 2.
The light is received by the light receiving element 21 via the light receiving element 8, and is converted into an electrical signal. Light receiving element 2 i. ．． ! :L. Then, for example, a photobin diode can be used. Furthermore, the light receiving element 2
An optical filter 29 is provided for 1, and the optical filter 29 detects flame 3 caused by a fire occurring in the smoke inspection space 30.
The light emitted from 2 is received by a light dissipating element 21 and is emitted. For example, the optical filter 29 has a wavelength of 8 80
The filter that selects light below nm is used up, and the flame 3
It is designed to receive light from 2 sources (near infrared rays and above).

Specifically, as shown in Figure 2, light emission. In addition to the optical system 6 for modulated light by the 1/lens 13 provided in the unit jO and the lens 33 provided in the light receiving unit 7 unit 20, the smoke detection space 30
The optical filter 29 shown in FIG. 1 is provided with a lens 34 whose lower side is an optical monitoring area.
The light can be incident on the light receiving element 21 via the light receiving element 21.

The electrical signal converted by the optical element 21 is amplified by the amplifying circuit 22 and then applied to the first filter 23 and the second filter 24. The first filter 23 emits light. :L
'': It has a passband of the frequency f1 of the modulation signal from the modulation circuit 11 provided in the transmission circuit 2.
The modulated signal component contained in the received light signal obtained from 2 is passed through. On the other hand, the second filter 24 may be used, for example, a filter that takes advantage of the frequency range of the FFL modulated signal, and allows the optical signal from the flame 32 obtained through the optical filter 29 to pass through. In other words, the light emitted from the flame has a flickering frequency of several Hz to several 10 I4 z, and by using a bandpass filter, it is possible to cut out the noise and avoid passing the light from the apricots caused by the fire. can.

The passing signal of the first filter ',' 2 3 is input to the first comparison circuit 25, and the first comparison circuit 25 has a threshold level set in advance according to the light attenuation rate for fire detection. The l. :． i, there.

On the other hand, the signal passed through the second filter 24 is given to a second comparison circuit 26, and the second comparison circuit 26 has a predetermined threshold value for determining an increase in the received light signal due to the light signal from the flame 32. The alarm circuit 27 is activated when the filter overconfidence exceeding this threshold value is obtained (.'a fire detection output is generated and the alarm circuit 27 is activated)].

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

First, in the steady monitoring state, the light-emitting element l is
2 is a light-emitting device, the modulated light is continuously emitted from the tatami light, Ni 1
・It is being fired towards 20. The modulated light received in the steady monitoring state is converted into an electrical signal by the light receiving element 21 and then amplified! After increasing the amplitude at '822, the signal is passed to the first and second filters 23 and 24.

The first filter 23 passes the modulated signal component of the frequency f1 included in the amplified signal l7 and inputs it to the first comparator circuit 25. At this time, since there is no attenuation of the modulated light due to smoke, the modulated light component is filtered.・Yutsu Uzu Shingetsu is sufficiently (more than) the threshold value of the first comparison circuit 25, and no fire detection signal is output.
, On the other hand, since the second filter 24 does not receive the light from the flame 32, the light passing through the second filter 24 becomes a substantially constant noise, and the second comparison Similarly, since the threshold value of the circuit 26 is sufficiently lower than the threshold value of the circuit 26, no fire detection signal is output.Next, if a fire occurs in the smoke detection space 30 as shown in FIG. , the smoke from the fire source becomes a light-emitting unit +-
Even the modulated light from 10 is cut off and attenuated, so that the level of the signal passing through the first filter 23, or rather the level of the modulated signal power, decreases! 7. When the threshold value of the first comparison circuit 25 is lowered or lower, a fire detection output is generated.

At the same time as the smoke, the light from the flame 32 passes through the optical filter 29 and passes through the light receiving element 2 1 15: the incident j7, the second filter. When the passage of 24 (J month 1, /beno 1.,') rises and exceeds the threshold set in the second comparison circuit 26, a fire detection signal is output. , Of course, if it is a smoldering fire that does not ignite, a warning will be issued by the fire detection signal from the first comparison circuit 25, which is based on the decrease in the level of the modulation signal. In the event of an explosive combustion fire (-8), which rarely occurs, the fire detection signal q from the second comparison circuit 26 will alert you.

In addition, the optical filter 28 installed on the light receiving unit 20
．． 29 is not formed in one piece), also, the lens 3
3, 34, for example, cut wavelengths of 880 nm or less.
It is also possible to use l-nons having a filter function.

Also, for example, a binfu spear that has the characteristic of cutting off wavelengths of 880n+++ or less! - Optical filters may be omitted by using diodes.

FIG. 3 is a configuration diagram showing another embodiment of the present invention; in this embodiment, an intermittent drive circuit 14 is newly installed in the light emitting units 1 and 10, and the light receiving unit 20 is newly installed.
The first filter 23 and the first comparison circuit 25 on the side are operated in the same way as the intermittent drive of the intermittent drive circuit l4.

That is, in FIG. 3, the light emitting element 712 of the light emitting unit l=i-0 is driven to emit light by the modulation signal of the frequency f1 from the modulation circuit 1, and at the same time, the intermittent drive circuit 14 drives the light emitting element 712 to emit light at a frequency higher than the modulation frequency f1. The intermittent sawing operation suppresses the light emitting time of the light emitting element 712 and prevents the current consumption KW and the deterioration of the element.

On the other hand, the configuration of the optical units 1 and 20 is the same as that in the embodiment shown in FIG.
filter 23 and the first filter 23. The intermittent drive signal 4 from the intermittent drive circuit 12b14 provided in the light emitting units 1 and 10 is input to the comparison circuit 25, and the intermittent drive signal is turned on.
The first filter 23 and the first comparator circuit 25 are operated only during this period. ．． Also, a second filter 24 and a second filter for detecting the optical signal 4 from the flame 32 are provided.
A signal obtained by inverting the driving signal of the intermittent drive circuit 4 by the inverter 35 is given to the comparison circuit 26 of the second filter 26, and only during the pause period of the intermittent drive, the second filter 2
4 and the second comparator circuit 26 are in the operating state;

Next, to explain the operation of the embodiment shown in FIG.
- The 10 light emitting elements 12 emit a modulation signal from the modulation circuit 11, an intermittent drive signal from the intermittent drive circuit 14, and variable beam light due to double displacement to the tube light unit 20.

In the light receiving unit 20, the intermittent drive period during which the light emitting element 12 of the light emitting unit 10 sends out the light emitting light] In this case, the first filter 23 and the first comparison circuit 25
is in the operating state, therefore, the light receiving element which has been converted into electric light by the light receiving element 21 and then intensified by the intensifier circuit 22 passes through the first filter 23 (7). The signal is input to a comparison circuit 25, and a comparison is made to determine whether it has fallen below a predetermined value or not.

Next, during the light emission stop period in which the intermittent driving circuit 1-4 of the light emitting units 1, 1, and 0 performs the light emission stop 11-, the intermittent movement signal Q) is inverted by the inverter 35 to drive the tatami light unit. The second filter 24 of No. 1 and No. 20 and the second comparator circuit father 6 are in operation, and in this case, the filter 24 of No. 2 is activated. Passing i,”?: Input to the second comparative road 2G (7,
Fires will be judged based on whether a predetermined threshold has been exceeded or whether the fire has occurred.

As shown in the embodiment of FIG.
In synchronization with the intermittent drive that turns to 0, the dimming of the modulated light due to smoke is determined during the intermittent drive period, and the dimming of the modulated light due to smoke is determined during the intermittent drive +1 period.
By determining the increase in sight in the near-infrared region or above, it is possible to clearly distinguish between the detection judgment of dimming and the detection judgment of brightness up to brightness12, and more accurate fire judgment can be made.

[Effects of the Invention] As explained above, according to the present invention, in addition to detecting the dimming due to smoke, there are two methods for detecting a fire by simultaneously capturing the brightening due to light from the flame. Fire can be reliably detected even if the light receiving unit 1 receives light from the flame directly and the receiving area increases.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of the present invention; Fig. 2 is an explanatory diagram of a vague state of the invention; Fig. 3 is an embodiment showing another embodiment of the invention. 10: Light emitting unit 1, 11: Modulation circuit 12: Light emitting elements 13, 33. 34: l no n/z 14; intermittent drive circuit 20: light receiving unit l/21: light receiving element 22 23 24 25 26 27 28, 30 32: amplifier circuit: first filter: second filter: first comparison Circuit: Second comparison circuit: Visual signal circuit 29: Optical filter: Smoke detection space: Flame

Claims (1)

[Claims] 1. A light emitting unit and a light receiving unit are disposed opposite to each other across a smoke detection space, and the light emitting unit is provided with a light emitting element that emits modulated light by being driven to emit light by a modulation signal from a modulation circuit, The light receiving unit includes a light receiving element that receives the modulated light and light caused by a fire and converts it into an electrical signal, a first filter that passes a modulated signal component included in the converted signal of the light receiving element, and the light receiving element. a second filter that passes an optical signal component caused by a fire included in the converted signal; and a first comparison that outputs a fire detection signal upon detecting that the first filter passing signal has fallen below a predetermined threshold. and a second comparator circuit that outputs a fire detection signal by detecting that the second filter passing signal exceeds a predetermined threshold value. .