JPS63276693A - Smoke sensing system - Google Patents

Abstract

PURPOSE:To economically monitor a wide area by a small number of smoke sensors by generating a light pulse train signal which includes address information on an abnormality occurrence area when an optical signal transmission line is cut off owing to the abnormality occurrence of smoke emission. CONSTITUTION:A projector 1-1 in a monitoring area A emits a single infrared- ray pulse at all times by mode switching. A light receiver 2-1 which receives the pulse inputs a single DC pulse corresponding to the output to the projector in a following monitor area and thus the output of a final light receiver is inputted to a center monitoring device 3 by successive relaying. If the single pulse is cut off by smoke, etc., the projector in a following area adjacent to a monitoring area where the smoke is emitted sends an infrared-ray light pulse train together with added address information on the monitoring area where the smoke is emitted. The pulse train is relayed by following light receivers and projectors and the output of the final light receiver is inputted to the device 3, which displays and indicates the address of the monitoring area where the smoke is emitted by detecting the address information.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a smoke detection system in a fire alarm or the like.

(Prior Art) FIG. 4 is a block diagram showing an example of a conventional smoke detection system.

In FIG. 4, 21 is a central monitoring device, 22-1 to 22-
n, 23-1 to 23-n,...N-1, N-n
are smoke detectors, and a plurality of smoke detectors are installed for each monitoring area A, B, . . . N.

The smoke detector is generally an optical switch that integrates an infrared light-emitting diode and an infrared light-receiving diode, facing each other at a certain distance, and when smoke enters the light path between the light-emitting diode and the light-receiving diode, the light-receiving diode Smoke is detected by reducing or cutting off the output current of the sensor.

Therefore, since the smoke detection range is narrow, in order to monitor a wide area, smoke detectors 22-1 to 22-n are used for monitoring area A, and smoke detectors 23-n are used for monitoring area B, as shown in FIG. A method has been adopted in which smoke detectors 1 to 23-n are distributed in a monitoring area, and each smoke detector is wired to a central monitoring device using electric wires such as communication cables.

(Problem to be Solved by the Invention) However, the smoke detection system with the above configuration requires a large number of smoke detectors in order to monitor a wide area, and the output of each smoke detector is centrally monitored using individual electric wires. Since it is necessary to connect to the device, there are problems in that a great deal of time is required for wiring work, which increases material costs and construction costs, and also requires a lot of time for maintenance and inspection.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned problems and to provide a smoke detection system that allows monitoring of a wide area economically with a small number of smoke detectors.

(Means for Solving the Problem) The present invention separates the light emitting part and the light receiving part of an optical switch, adds various functions to each, and sets the light emitter and light receiver as separate units. The monitoring areas are installed in a plurality of monitoring areas so as to face each other. The output of each receiver is connected by wire to the input of a projector in an adjacent monitoring area, and the output of the final receiver is connected by wire to a central monitoring device located outside the monitoring area, forming a serial optical signal transmission path. In this way, if a single optical pulse signal is constantly and periodically emitted from the emitter in the first monitoring area, and the single DC pulse signal generated at the output of the final receiver is input to the central monitoring device, it is normal. When the optical signal transmission path is interrupted due to an abnormality such as smoke generation, a light pulse train signal containing address information of the abnormality area is sent from a light emitter connected to a receiver installed in the abnormality area. It is designed to emit light repeatedly at regular intervals to notify the central monitoring device of the occurrence of an abnormality and the area in which it occurs.

(Function) The projector used in the present invention uses e-light such as infrared light or laser light to significantly increase the peak output compared to continuous light emission, extend the reach of the light, and widen the surveillance area. It is designed to cover the area with a small number of emitters and receivers. When a DC pulse is applied to the input terminal of the projector, it drives an infrared light emitting diode and emits an infrared light pulse with the same width as the input DC pulse. However, if the DC pulse is not applied to the input for a certain period of time, the built-in pulse generation circuit operates to intermittently generate a series of pulse trains which drive an infrared light emitting diode to emit a train of infrared light pulses. Address information from an address addition circuit connected to the pulse generation circuit can be added to the pulse train, and the address information is a start bit and an address number assigned to each monitoring area in binary or BCD format.
Can be set by code and address setting switch.

The projector in the first monitoring area is configured to constantly emit a single pulse of infrared light by mode switching, and the receiver that receives the single pulse of infrared light transmits the single DC pulse generated at its output to the adjacent subsequent It is assumed that there is no abnormality if the input is sent to the projector in the monitoring area, relayed sequentially, and the final receiver output is input to the central monitoring device.If the single pulse of infrared light is blocked by smoke, etc., smoke is generated. A floodlight in a subsequent monitoring area adjacent to the monitoring area emits an infrared light pulse train to which address information of the monitoring area that generated smoke is added, which is relayed by subsequent receivers and floodlights, and the output of the final receiver is sent to the central monitoring device. The central monitoring device detects the address information and displays and reports the address of the monitored area where smoke has occurred.

(Embodiment) FIG. 1 is a system block diagram of an embodiment of the present invention, in which three monitoring areas A, B, and C are monitored.

FIG. 2 is an equipment layout diagram of this embodiment.

In FIGS. 1 and 2, 1-1.1-2 and 1-3 are projectors, 2-1.2-2.2-3 are light receivers, and 3 is a central monitoring device.

The light projector and light receiver used in the present invention are basically an infrared light switch with a light emitting part and a light receiving part separated and each having various functions added thereto.

FIG. 3 shows a block diagram of a light projector and a light receiver used in an embodiment of the present invention. In Fig. 3, 1 is a light emitter, 2 is a light receiver, 4 is a pulse generation circuit, 5 is an LED drive circuit, 6 is an infrared light emitting diode, 7 is an address adding circuit, 8 is an address setting switch, and 9 is an infrared light receiving diode. , 1o is an amplifier, 11 is an input terminal, 12 is an output terminal, and 13 is a monitoring area.

The projector 1 includes a pulse generating circuit 4, an LED driving circuit 5, an infrared light emitting diode 6, an address adding circuit 7, and an address setting switch 8.

In a normal state, when a DC pulse is applied to the input terminal 11, the projector 1 drives the LED drive circuit 5 and the infrared light emitting diode 6 to emit an infrared light pulse having the same width as the input pulse. The pulse generation circuit 4 has an input terminal 11
It is inactive while DC pulses are periodically applied to the input terminal 11, but after a certain period of time has elapsed since the DC pulses are no longer applied to the input terminal 11, a series of pulse train signals are periodically generated.

Address information can be added to the pulse train signal by an address adding circuit 7, and the address adding circuit 7 can set an address using an address setting switch 8 in binary or BCD code.

Note that the pulse generating circuit 4 can also be configured to generate a single Noculus at a constant cycle by switching modes.

When the pulse train from the pulse generating circuit 4 is applied to the LED driving circuit 5, the infrared light emitting diode 6 is driven to emit an infrared light pulse train signal having address information. The light receiver 2 is composed of an infrared light receiving diode 9 and an amplifier IQ.The infrared light pulse train signal emitted from the projector passes through a monitoring area 13 and reaches the infrared light receiving diode 9, and its output is amplified by an amplifier 10. and outputs a DC pulse to the output terminal 12.

, FIG. 2 is an equipment layout diagram of an embodiment of the present invention, with floodlights 1-1, 1-2, 1-3 in monitoring areas A, B, and C, respectively.
, a light receiver 271.2-2.2-3 and a monitoring device 3 are installed. The emitter and the receiver are arranged so that the light path between them is not blocked by obstacles and the infrared light pulse signal emitted from the emitter can be effectively passed through the monitoring area within the range where the receiver can receive the light. Install. ′
The emitter 1-1 is configured to emit a single pulse of infrared light at a constant period by switching the mode of the pulse generating circuit 4, and the single pulse of infrared light passes through the monitoring area A and is transmitted to the receiver 2-1. 1, the output terminal 12 of the light receiver 2-1
generates a DC pulse, which is sent to the light projector 1-2 in the monitoring area B by an electric wire. When the direct current pulse is applied to the input terminal 11 of the projector 1-2, the projector 1-2 emits an infrared light pulse having a width about the same width as the input DC signal. The infrared light 1? The laser passes through the monitoring area B and reaches the receiver 2-2, drives the emitter 1-3 in the same order as above to emit an infrared light pulse, passes through the monitoring area C and reaches the receiver 2-3. , and its output is input to the central monitoring device 3.

FIG. 5 is a time chart of an embodiment of the present invention.

In FIG. 5, (a) Infrared light output pulses P 1 + P 2 p ' of the projector 1-1. Assuming that no smoke was generated at the time when P 3 was emitted, the infrared light output pulses P 1 , P 2 + P 3 Ha(o) l G'3
As shown in (p), (e), and (f), the receiver 2
-1 → Light emitter 1-2 → Light receiver 2-2 → Light emitter 1-3 → Transmitted to light receiver 2-3, and the DC pulse generated at the output of the light receiver 2-3 is input to the central monitoring device 3. Show that. When the central monitoring device 3 is thus receiving a single pulse at a constant cycle, it indicates that there is no smoke in the monitoring areas A, B, and C.

Subsequently, the infrared light output pulse P of the projector 1-1 in (a)
After 4, when smoke is generated in the monitoring area A and the infrared light pulse no longer reaches the light receiver 2-1, (b) no DC pulse is generated in the output of the light receiver 2-1. Therefore,
Since DC pulses are no longer applied to the input terminal of the projector 1-2, the pulse generation circuit 4 of the projector 1-2 starts operating after a certain period of time and generates a pulse train signal containing address information of the monitoring area A where smoke has occurred. is generated at a constant period, and the infrared light emitting diode 6 is driven via the LED drive circuit 5 to emit an infrared light pulse train signal.

The address information includes a start bit and an address for synchronization, and the address is set to binary or BC by an address setting switch 8 connected to an address adding circuit 7.
It can be set using a D code and is applied to the pulse generating circuit 4 via the address adding circuit 5. The infrared light pulse train signal is relayed by the receiver 2-2 → emitter 1-3 → receiver 2-3, and the DC pulse generated at the output of the receiver 2-3 is input to the central monitoring device 3 to detect the address. is,
The central monitoring device 3 displays that the monitored area A is where smoke has occurred.

Although the embodiments described above are extremely small-scale, if there are many monitoring areas, the optical signal transmission lines of all monitoring areas should not be connected in series, but the monitoring areas may be divided into several groups, and the optical A signal transmission path is formed, and the final receiver output of each optical signal transmission path is introduced into the central monitoring device.In a group of monitoring areas, two routes of optical signal transmission paths are formed and each optical signal transmission direction is controlled. By reversely introducing it into the central monitoring device, it is possible to deal with smoke generation due to multiple simultaneous fires, etc.

(Effects of the Invention) As described in detail above, according to the present invention, a wide monitoring area can be monitored with a small number of emitters and receivers, and the number of wiring such as communication cables can be reduced, so material costs and construction costs can be reduced. The advantage is that significant savings can be made and smoke detection systems monitoring many large monitoring areas can be constructed very economically. It is also effective when constructing a smoke detection system for a long-distance, curved area such as a tunnel.

[Brief explanation of drawings]

Figure 1 is a system block diagram of one embodiment of the present invention, Figure 2 is a system block diagram of an embodiment of the present invention.
The figure is an equipment layout diagram of an embodiment of the present invention, Figure 3 is a block diagram of a projector and receiver used in an embodiment of the present invention, and Figure 4
The figure is a block diagram of a conventional smoke detection system, and FIG. 5 is a time chart of an embodiment of the present invention. 1.1-1.1-2. ．． 1-3...Floodlight, 2゜2-
1.2-2.2-3... Light receiver, 3... Central monitoring device, 4... Pulse generation circuit, 5... LED drive circuit, 6... Infrared light emitting diode, 7...・Address addition circuit, 8...Address setting switch, 9. Outside line light receiving diode, 1o...Amplifier, 11...Input terminal, 12...Output terminal, I3...Monitoring area, 21...
・Central monitoring device, 22-1, 22-n, '23-1
, 23-n. N-1, N-n...Smoke detector. Patent applicant: Oki Electric Industry Co., Ltd. Figure 1 System block diagram of an embodiment of the present invention Figure 2 Equipment layout diagram of an embodiment of the present invention

Claims (1)

[Claims] In a smoke detection system for a fire alarm that monitors a plurality of areas, a projector and a receiver are provided in each monitoring area so as to pass through the monitoring area and face each other, and the output of each receiver is A serial optical signal transmission path is formed by connecting the input of the emitter in the adjacent monitoring area and inputting the final receiver output to a central monitoring device installed outside the monitoring area, and constantly and periodically transmitting signals from the emitter in the first monitoring area. emit a single optical pulse signal at
If the single DC pulse signal generated at the final receiver output is input to the central monitoring device, it will indicate normality, and if the optical signal transmission path is interrupted due to an abnormality such as smoke, the light will be received in the abnormality area. A smoke device characterized in that a light pulse train signal containing address information of the area where the abnormality occurs is repeatedly emitted at a fixed period from a floodlight connected to the device, thereby reporting the occurrence of the abnormality and the area where the abnormality is occurring to a central monitoring device. sensing system.