JPH084499A - Fire protection system in tunnel - Google Patents

Abstract

PURPOSE:To securely detect the happening of fire by installing an optical fiber in the lengthwise direction in a tunnel and measuring the light scattering position and the temperature at this position by utilizing the echo due to the light scattering irradiated from one end of the optical fiber. CONSTITUTION:When a temperature detection part 6 detects the sharp temperature rise in a certain division 20b from the echo due to the rearward scattering light of an optical fiber 1, the temperature information is transmitted to a center disaster prevention board 7, and displayed on a CRT. Then, the fire judgement part on the center disaster prevention board 7 analyzes the temperature information on the basis of each standard of the temperature rise rate, relative temperature anomaly, and absolute temperature anomaly, and one or two standards are related, the generation of fire disaster is judged. Ejection of water is instructed to the relaying device 24b of the division 20b, and the relaying device 24b opens an automatic valve 27b, and water is ejected from a water ejecting head 28b, and fire distinguishing operation is carried out. Accordingly, the fire happening plate can be specified correctly, and the water ejecting equipment can be effectively operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel disaster prevention facility, and more particularly to a tunnel disaster prevention facility using an optical fiber as a temperature sensor.

[0002]

2. Description of the Related Art Conventionally, a disaster prevention facility for a tunnel is usually divided into a plurality of compartments in the length direction of the tunnel, and a flame detector for monitoring a fire is provided in each compartment, and water is sprayed to the compartment when a fire occurs. It is designed to extinguish fire.

FIG. 9 is a system diagram showing an example of conventional tunnel disaster prevention equipment. In the figure, reference numerals 20a, 20b, ... Are sections in which the length direction of the tunnel is divided into appropriate lengths (for example, 25 m), and a plurality of flame detectors 22 are installed on the ceiling of each section 20a, 20b ,. The flame detectors 22 are connected to the central disaster prevention board 21 by transmission lines 23. 24a, 24b, ... are each section 20a, 20
Each of the repeaters 24a, 2 is a repeater installed for each b ,.
.. are connected to the central disaster prevention board 21 by transmission lines 25.

Reference numeral 26 denotes a water pipe, which is used for each of the sections 20a, 20b,
Automatic valves 27a, 27b, ... Are provided in the branch pipes branched for each ... And their opening / closing is controlled by commands from the repeaters 24a, 24b ,. 28a, 28b, ... are water discharge heads connected to the automatic valves 27a, 27b ,.

In the above-mentioned tunnel disaster prevention equipment,
For example, when a fire occurs in the section 20d, the section 20d
The flame detector 22 installed at d detects this and sends a fire signal to the central disaster prevention board 21. Upon receiving the fire signal, the central disaster prevention board 21 confirms the occurrence of the fire and its place (section),
The command is sent to the repeater 24d of the section 20d. In response to this, the repeater 24d opens the automatic valve 27d, discharges water from the water discharge head 28d, and extinguishes the fire.

[0006]

Since the conventional tunnel disaster prevention equipment uses the flame detector as the fire detector as described above, the malfunction of the tunnel disaster prevention equipment may occur due to the light of the automobile running in the tunnel. Also, when a fire occurs due to some shade, there is a problem that the flame cannot be detected because it cannot be seen.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a tunnel disaster prevention equipment which is capable of accurately detecting the location of a fire without causing a malfunction. It is a thing.

[0008]

The tunnel disaster prevention equipment according to the present invention is constructed as follows. (1) Fire is generated by installing an optical fiber in the length direction inside the tunnel and measuring the light scattering position and the temperature at this position by using the echo caused by the scattering of the light incident from one end of this optical fiber. Is detected.

(2) Based on an optical fiber installed in the length direction in the tunnel and an echo caused by scattering of light incident on the optical fiber caused by a temperature change in the tunnel, at a constant distance from the starting end of the optical fiber. The temperature detecting section for detecting the temperature of the above, and the fire determining section for determining the presence or absence of a fire based on the information from the temperature detecting section.

(3) Incident on a flame detector installed at a predetermined interval in the length direction in the tunnel, an optical fiber installed in the length direction in the tunnel, and an optical fiber generated by a temperature change in the tunnel. A temperature detection unit that detects the temperature at a fixed distance from the beginning of this optical fiber based on the echo due to scattered light, and a fire determination unit that determines the presence or absence of a fire based on information from the flame detector and the temperature detection unit. It is equipped with and.

(4) In the tunnel disaster prevention equipment of the above (1) to (3), an anemometer for detecting the wind speed in the tunnel is installed in the tunnel, and the anemometer is installed in the temperature detecting section or the fire discriminating section. Based on the information from the optical fiber or the optical fiber and the information from the flame detector, the correction means for correcting the location of the fire is provided.

(5) In the tunnel disaster prevention equipment of the above (1) to (4), two echoes having different wavelengths are used and the intensity ratio thereof is a function of temperature. (6) The fire discriminating unit in (2) to (5) above determines the occurrence of a fire as follows. (A) A temperature rise rate threshold value is set in advance, and when the measured temperature rise rate exceeds the threshold value, it is determined that a fire has occurred. (B) The average temperature is calculated for each constant distance from the starting end of the optical fiber, and if the temperature at a certain location is higher than the preset temperature range with respect to the average temperature, it is determined that a fire has occurred.

(C) The upper limit of the maximum temperature is set for each constant distance from the start end of the optical fiber, and if the temperature at a certain distance is higher than the upper limit, it is determined that a fire has occurred. (D) Two or more of the above (a) to (c) are combined to determine the occurrence of a fire.

[0014]

According to the present invention, an optical fiber is installed as a temperature sensor on the ceiling of a tunnel or the like to detect the occurrence of fire. The temperature sensor using the optical fiber is
Although it has made rapid progress due to technological innovation in recent years,
Since the principle and configuration of the measurement are not well known, the measurement principle will be described here.

The optical fiber temperature sensor uses the entire length of one optical fiber as a temperature sensor, and also functions as a transmission line for the detection information, so that the temperature distribution over the entire length from one end to the other end of the optical fiber. It is an epoch-making temperature sensor that can measure all at once.

Therefore, the measurement principle of this temperature sensor will be described below with reference to the measurement principle diagram of FIG. 7 and the scattering phenomenon diagram of FIG. First, as shown in FIG. 7, when the incident pulsed light 2 is made incident from one end of the optical fiber 1, it propagates in the optical fiber 1 as transmitted light 3. Then, for example, when a situation that causes a fire occurs at the point A of the optical fiber 1 (for example, when the temperature in the tunnel rises sharply), the thermal vibration of the glass at the point A as shown in FIG. Occurs, the vibration between the atoms forming the glass becomes larger than that at room temperature, so that Raman scattered light 4 having a wavelength different from that of the incident light is generated depending on the temperature at that time.

That is, in addition to the Rayleigh scattered light having the same wavelength as the wavelength λ ₀ of the incident light, two Raman scattered lights 4 having different wavelengths from the incident light are generated due to the interaction between the incident light and the thermal vibration of the glass. To do. The Raman scattered light 4 becomes Stokes light with a long wavelength (λ ₀ + λ) when the incident light loses energy by the vibration of the glass, and conversely becomes Anti-Stokes light (λ ₀ −λ) with a short wavelength when energy is received. Become. Since the intensity of the Raman scattered light 4 depends on the vibration of the glass, that is, the temperature of the glass, the intensity of the Raman scattered light 4 increases as the temperature rises.

A part of the Raman scattered light 4 thus generated returns to the incident end again as the back scattered light 5, as shown in FIG. Distance x from propagation time t until returning,
That is, the distance from the incident end to point A can be measured. That is, in the optical fiber 1, the position where the temperature suddenly rises is identified, and the position can be detected. Therefore, 1
Each optical fiber 1 by installing one or a plurality of optical fibers 1
By forming a monitoring unit that can be monitored for each and configuring a fire detection system that functionally integrates these, it is possible to accurately detect the occurrence of a fire and its position. In this case, light is used, but the principle is the same as the radar using radio waves.

Therefore, the temperature at point A can be measured by separating and detecting only the Raman scattered light returning to the input end with an optical filter and measuring the intensity thereof. In the present invention, two Raman scattered lights having different wavelengths are used together,
For example, since the intensity ratio is used as a function of temperature, the measurement accuracy can be improved.

[0020]

FIG. 3 is a block diagram showing the principle structure of the present invention. The present invention is a central part composed of an optical fiber (sensor section) 1, a temperature detecting section 6, a fire discriminating section 14 including a computing unit, a CRT 15 and the like. It is composed of a disaster prevention board 7. In order to measure the temperature in the tunnel, pulsed light 2 from a light projecting element 9 such as a semiconductor laser is made incident on an optical fiber 1 installed on a ceiling or the like by a pulse drive circuit 8, and the transmitted light 3 is passed through the position. The Raman scattered light described above is generated, and part of it returns to the temperature detection unit 6 as the backscattered light 5. The returned backscattered light 5 is separated into anti-Stokes light Ia and Stokes light Is by a filter in the optical demultiplexer 10, converted into electric signals by the light receiving elements 11, respectively, amplified by the amplifier circuit 12, and then processed by the processing device 13. input. In the processing device 13, it is converted into a digital amount at each sampling time and added to the memory corresponding to each sampling point (proportional to the distance). Then, the above operation is automatically repeated a predetermined number of times (integration processing).

At the final time (N times) of this integration processing, the integrated value in each memory is divided by N and averaged (this is called averaging processing), so that noise (background) is largely removed. Then, the temperature is calculated from the intensity ratio of Ia and Is stored in each memory. Since each memory corresponds to the distance, the temperature distribution is finally obtained by this. This information is input to the central disaster prevention board 7 to confirm the presence or absence of a fire and its location, and display the temperature distribution inside the tunnel along the optical sensor 1 on the CRT 15. With the data of the temperature distribution thus obtained, the occurrence of a fire in the tunnel can be detected quickly and accurately.

FIG. 4 is a diagram showing the relationship between the intensity ratio (vertical axis) of Ia / Is and the temperature (horizontal axis). The solid line indicates a logical value and the circle indicates an experimental value. As is clear from the figure, Ia
It can be seen that the intensity ratio of / Is is a function of temperature and is closely dependent. Therefore, the temperature distribution along the optical fiber 1 can be known by measuring the intensity of these Raman scattered lights as a function of time after the incident pulsed light 2 is incident on the optical fiber 1.

The optical fiber 1 as a temperature sensor has a distance resolution (sensor unit length) as a detection sensitivity of 1 m, a measurement temperature range of −50 ° C. to + 500 ° C., and a temperature accuracy of ±.
It has an excellent performance of 1 ° C. In addition, the temperature detector 6 installed in the tunnel is made of stainless steel (SUS steel).
Due to its structure, it has a high strength, and it can be operated without being affected by high temperature and high humidity, etc. Furthermore, since it can be collectively controlled by the central disaster prevention panel 7, monitoring and maintenance are easy.

Embodiment 1 FIG. 1 is a system diagram of a first embodiment of the present invention. The same parts as those in the conventional example of FIG. 9 are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the optical fiber 1 is used as a temperature sensor instead of the flame detector, 1 is an optical fiber installed on the ceiling of a tunnel, and 6 is a rear side of the optical fiber 1 based on a temperature change in the tunnel. Due to the scattered light echo, a fixed distance from the beginning (hence the section 20
a, 20b, ...) temperature detecting section for detecting the temperature
It is connected via a transmission line 19 to a central disaster prevention board 7 equipped with a fire discrimination unit 14 and a CRT 15. The temperature detecting unit 6 is installed in, for example, a tunnel, and the central disaster prevention board 7 is installed in, for example, a central control room.

The optical fiber 1 as described above is installed, for example, along the length direction of the side wall of the tunnel T as shown in FIG. 2 (a), or as shown in FIG. 2 (b).
It is installed at an angle on the ceiling of the tunnel T.
Note that the tunnel T usually has two lanes in many cases, and if the optical fibers 1 are provided at two locations on the cross section, it is possible to confirm in which lane the fire has occurred. Also, FIG.
As shown in (c), one optical fiber 1 is connected to the tunnel T.
The temperature distribution in the tunnel T can be grasped in detail by installing it in the length direction while alternately folding back along the width direction. Further, the installation place and the installation state may be appropriately selected depending on the situation. In the example, the optical fiber 1 was used in which the optical fiber core wire was coated with a stainless tube having a thickness of 0.2 mm and an outer diameter of about 2.4 mm.

In the present embodiment configured as described above, the temperature inside the tunnel is determined by the optical fiber 1 installed therein.
As a result, each section 20a, based on the principle described in FIG.
20b, ... Is measured by the temperature detection unit 6, and the fire determination unit 14 determines whether or not a fire has occurred, and the temperature inside the tunnel is displayed on the CRT 15 (see FIG. 3).

In the tunnel disaster prevention equipment using the optical fiber 1 as a temperature sensor, the fire discrimination unit 14
Therefore, the presence or absence of a fire is determined by one or a combination of two or more of the following criteria. (1) Temperature rise rate The temperature rise rate threshold is set in advance, and the value obtained by dividing the temperature difference between the previously acquired data and this time acquired data by the data acquisition cycle (hence the temperature increase rate) is If it exceeds the threshold value, it is judged that a fire has occurred.

(2) Relative temperature abnormality An average temperature is calculated for each fixed distance (section) from the start end of the optical fiber, and if the temperature at a certain place is higher than the preset temperature range with respect to the average temperature, a fire occurs. To determine. (3) Absolute temperature abnormality An upper limit of the maximum temperature is set for each constant distance (section) from the start end of the optical fiber, and if the temperature of a certain place is higher than the upper limit value of that place, it is determined that a fire has occurred.

In the present embodiment as described above, when the temperature detecting section 6 detects that the temperature of a certain section (for example, 20b) sharply rises by the echo by the backscattered light of the optical fiber 1, the temperature is detected. The information is transmitted to the central disaster prevention board 7 and displayed on the CRT 15. Central disaster prevention board 7
The fire discriminating unit 14 uses this temperature information as the criterion (1) described above.
Analysis is performed based on (3) to (3), and when one or more of the criteria is met, it is determined that a fire has occurred, and the relay device 24b of the section 20b is instructed to discharge water. Thereby, the repeater 24
In b, the automatic valve 27b is opened to discharge water from the water discharge head 28b to extinguish the fire.

Embodiment 2 FIG. 5 is a system diagram of a second embodiment of the present invention. In this embodiment, the conventional tunnel disaster prevention equipment in which the flame detector 22 is installed is provided with the optical fiber 1 as the temperature sensor and the temperature detection unit 6, and the fire detection unit 14 is provided in the fire determination unit 14 of the central disaster prevention panel 7. 22 fire signals are input.

In this embodiment, the fire discriminating unit 14 is
This is to make it more accurate by determining that a fire has occurred when the temperature information from the temperature detection unit 6 and the information on the fire occurrence location and the fire signal from the flame detector 22 overlap. The operation after determining the occurrence of fire is the same as in the case of the first embodiment.

Embodiment 3 FIG. 6 is a system diagram of a third embodiment of the present invention. In this embodiment, an anemometer 32 for measuring the wind speed in the tunnel is provided at an appropriate position in the tunnel, and the temperature detection unit 6 or the fire discrimination unit 14 is based on the information from the anemometer 32. The correction means is provided to correct the location of the fire. Usually, since there is wind in the tunnel, when a fire occurs, the wind causes a flame to flow, causing backscattered light in the optical fiber 1 at a place different from the place where the fire actually occurs, or Flame detectors at different locations may output fire signals. Since this wind varies depending on the season, time, traffic volume, and position, it is desirable that the wind be constantly measured, but it may be measured at predetermined intervals and stored. Then, the location of the fire can be accurately known by using the relative data of the positional deviation based on the wind speed.

In this embodiment, the fire discriminator 14 is
The temperature information and the position information from the temperature detection unit 6 are input, or the fire signal from the flame detector 22 is further input to determine the presence or absence of a fire, and the information from the anemometer 32 is input to detect a fire. Correct the location of the fire and detect the exact location of the fire. Then, a signal was sent to the repeater at the place where the fire broke out, and the automatic valve was activated to discharge water.
You can surely extinguish the fire.

[0034]

As is apparent from the above description, according to the present invention, the following effects can be obtained. (1) An optical fiber was installed in the length direction of the tunnel, and the occurrence of a fire was detected using the echo due to the scattering of the light incident from one end of the optical fiber. This enables long-distance fire monitoring, and even if an optical fiber is installed inside a tunnel, it is not affected by adverse environments such as dust and corrosive gases, electrical noise, electromagnetic waves, etc., and maintenance is easy. It is possible to obtain highly reliable tunnel disaster prevention equipment.

(2) An optical fiber installed in the length direction in the tunnel, a temperature detecting section for detecting the temperature at a constant distance from the starting point of the optical fiber in the tunnel, and a fire from information from the temperature detecting section. Since the fire discriminating unit for discriminating the occurrence or non-occurrence of the fire is provided, the effect of the above (1) can be reliably obtained.

(3) A flame detector installed at a predetermined interval in the length direction in the tunnel, an optical fiber installed in the length direction in the tunnel, and at a constant distance from the starting point of the optical fiber in the tunnel. A temperature detection unit that detects the temperature of
Since the fire discriminating unit for discriminating the presence or absence of a fire is provided based on the information from the flame detector and the temperature detecting unit, the effect of the above (1) can be more reliably obtained.

(4) In the tunnel disaster prevention equipment of the above (1) to (3), an anemometer is provided in the tunnel, and the location of the fire is detected in the temperature detecting section or the fire discriminating section based on the information from the anemometer. Since the correction means is provided, the location of the fire can be accurately specified, and the water discharge facility can be effectively operated.

(5) In the tunnel disaster prevention equipment of the above (1) to (4), since the two echoes having different wavelengths are used and the intensity ratio thereof is a function of temperature, the measurement accuracy can be further improved. (6) In addition, in the tunnel disaster prevention equipment of (2) to (5), the occurrence of a fire is determined by any one or a combination of two or more of the temperature rise rate, the equivalent temperature abnormality, and the absolute temperature abnormality. Since it is set, it is possible to reliably detect the occurrence of a fire.

[Brief description of drawings]

FIG. 1 is a system diagram of a first embodiment of the present invention.

2A, 2B, and 2C are schematic views showing an example of an installed state of an optical fiber.

FIG. 3 is a block diagram showing the basic configuration of the present invention.

FIG. 4 is a diagram showing the relationship between the intensity ratio of Ia / Is and temperature.

FIG. 5 is a system diagram of a second embodiment of the present invention.

FIG. 6 is a system diagram of a third embodiment of the present invention.

FIG. 7 is a principle diagram of temperature measurement by an optical fiber.

8 is an explanatory diagram of a light scattering phenomenon of FIG.

FIG. 9 is a system diagram of an example of a conventional tunnel disaster prevention facility.

[Explanation of symbols]

 1 Optical Fiber 6 Temperature Detection Section 7 Central Disaster Prevention Panel 14 Fire Discrimination Section 20a, 20b, ... Section 22 Flame Detector 24a, 24b, ... Repeater 26 Water Pipe 27a, 27b, ... Automatic Valve 28a, 28b, ... Water Discharge Head 32 Anemometer

Claims (9)

[Claims] 1. In a tunnel disaster prevention facility that detects a fire in a tunnel and discharges water to the place where the fire occurred to install a fiber optic in the length direction of the tunnel, and inject light from one end of the fiber. Tunnel disaster prevention equipment characterized by detecting the occurrence of fire by measuring the scattering position of the light and the temperature at the position by utilizing the echo due to the scattering of. 2. In a tunnel disaster prevention facility that detects a fire in a tunnel and discharges the water to the place where the fire occurred to cause fire, which is caused by an optical fiber installed in the length direction of the tunnel and a temperature change in the tunnel. A temperature detection unit that detects a temperature at a constant distance from the start end of the optical fiber based on an echo due to scattering of light that has entered the optical fiber, and a fire that determines whether or not a fire has occurred based on information from the temperature detection unit. Tunnel disaster prevention equipment characterized by having a discrimination unit. 3. A tunnel disaster prevention equipment for detecting a fire in a tunnel, discharging the water to the place where the fire has occurred, and extinguishing the fire. A flame detector installed at a predetermined interval in the length direction of the tunnel, and a fire detector in the tunnel. An optical fiber installed in the length direction, and a temperature detecting section for detecting a temperature at a constant distance from the starting end of the optical fiber based on an echo caused by scattering of light incident on the optical fiber caused by a temperature change in the tunnel. And a fire discriminating unit that discriminates whether or not a fire has occurred based on information from the flame detector and the temperature detecting unit. 4. An anemometer for detecting the wind speed in the tunnel is installed in the tunnel, and an optical fiber or an optical fiber and a flame detector are provided in a temperature detecting section or a fire discriminating section based on the information from the anemometer. The correction means for correcting the location of the fire based on the information from the device is provided.
Tunnel disaster prevention equipment described in 2 or 3. 5. An echo according to claim 1, wherein two echoes having different wavelengths are used and the intensity ratio thereof is a function of temperature.
Tunnel disaster prevention equipment described in 2, 3 or 4. 6. The fire discriminating unit sets a threshold value of a temperature rise rate in advance, and judges that a fire has occurred when the measured temperature rise rate exceeds the threshold value. The tunnel disaster prevention equipment according to claim 2, 3, 4, or 5. 7. The fire discriminating unit calculates an average temperature for each constant distance from the start end of the optical fiber, and if a temperature at a certain place is higher than a preset temperature range with respect to the average temperature, a fire has occurred. The tunnel disaster prevention equipment according to claim 2, 3, 4, or 5, wherein 8. The fire discriminating unit sets an upper limit of the maximum temperature for each constant distance from the start end of the optical fiber,
The fire is judged to have occurred when the temperature at a certain place is higher than the upper limit.
Or the tunnel disaster prevention equipment described in 5. 9. The tunnel disaster prevention equipment according to claim 2, 3, 4 or 5, wherein the fire determination unit determines the occurrence of a fire by combining two or more of claims 6, 7, and 8. .