阅读说明：本技术 一种分布式感温火灾探测器及探测系统 (Distributed temperature-sensing fire detector and detection system ) 是由 吴锋 张文 张鸿鹄 李凡凡 刘嘉豪 徐强 李仲强 赵梦露 许明政 汪臻 宋仁杰 于 2020-11-23 设计创作，主要内容包括：本发明涉及火灾检测领域,公开了一种分布式感温火灾探测器及探测系统,该探测器包括感温光纤、激光发射器、波分复用器以及探测主机,通过激光发射器发生激光脉冲,激光脉冲沿感温光纤向前传输,激光与光纤介质相互作用,产生极为微弱的背向拉曼散射光,经波分复用器分离后由高灵敏光电探测器所探测,再经高速信号采集和微弱信号处理,得到背向散射信号光的光强比值和返回时间,从而实时获得温度分布信息。分布式光纤温度传感系统作为国内外最先进的线型火灾探测器,具有测量距离长、无测量盲区、实时测量等优点,在电力、交通隧道、地铁、石化、大坝等领域均有广泛应用。(The invention relates to the field of fire detection, and discloses a distributed temperature-sensing fire detector and a detection system, wherein the detector comprises a temperature-sensing optical fiber, a laser emitter, a wavelength division multiplexer and a detection host, laser pulses are generated by the laser emitter, the laser pulses are transmitted forwards along the temperature-sensing optical fiber, the laser interacts with an optical fiber medium to generate very weak back Raman scattering light, the back Raman scattering light is detected by a high-sensitivity photoelectric detector after being separated by the wavelength division multiplexer, and then the light intensity ratio and the return time of the back scattering signal light are obtained through high-speed signal acquisition and weak signal processing, so that the temperature distribution information is obtained in real time. The distributed optical fiber temperature sensing system is used as the most advanced linear fire detector at home and abroad, has the advantages of long measuring distance, no measuring blind area, real-time measurement and the like, and is widely applied to the fields of electric power, traffic tunnels, subways, petrifaction, dams and the like.)

1. A distributed temperature-sensitive fire detector, comprising:

the temperature sensing optical fiber (1), a plurality of detection points (11) are sequentially arranged on the temperature sensing optical fiber (1) along the extending direction thereof;

the laser emitter (2) is used for emitting laser pulses to the access end of the temperature sensing optical fiber (1), the laser pulses are transmitted along the extension direction of the temperature sensing optical fiber and interact with each detection point (11) to generate weak backward Raman scattering light and return along the temperature sensing optical fiber (1);

a wavelength division multiplexer (3) for separating out the back-Raman scattered light;

the temperature detection device comprises a detection host (4), wherein the detection host (4) is connected with an access end of a temperature sensing optical fiber (1) through a channel, a high-speed signal acquisition unit and a weak signal processing unit are arranged in the detection host (4), returned back Raman scattering light separated by a wavelength division multiplexer (3) is detected by the detection host (4) and processed by the high-speed signal acquisition unit and the weak signal processing unit to obtain the light intensity ratio and the return time of the back Raman scattering light of each detection point (11), and according to the relation between the light intensity and the temperature, the temperature value and the temperature change rate of each detection point (11) are obtained, so that the temperature distribution information is obtained in real time.

2. The distributed temperature-sensitive fire detector according to claim 1, wherein the backscattered raman scattered light comprises temperature-sensitive anti-stokes light and temperature-insensitive stokes light, and the wavelength division multiplexer (3) is configured to separate the temperature-sensitive anti-stokes light.

3. The distributed temperature-sensitive fire detector of claim 1, wherein the light intensity is related to temperature by the following equation:

wherein, Δ v represents a Raman frequency shift quantity, k is a Boltzmann constant, h is a Planckian constant, T is an absolute temperature, l is a light intensity, α is an attenuation coefficient, A is a ratio of stokes light to anti-stokes light in Raman scattering light, and S (T, l) is an array containing the absolute temperature T and the light intensity l;

the distance calculation formula of the detection point (11) is as follows:

wherein, L is the distance of the detection point, t is the return time of the laser, and c is the speed of light.

4. The distributed temperature-sensitive fire detector according to claim 1, wherein the number of the temperature-sensitive optical fibers (1) is not more than 8, and the total length of the 8 temperature-sensitive optical fibers (1) is not more than 15 km.

5. The distributed temperature-sensitive fire detector according to claim 1, wherein the temperature-sensitive optical fiber (1) comprises an optical fiber core (12), a spiral steel pipe layer (13), a Kevlar layer (14), a stainless steel woven mesh layer (15) and an outer sheath (16) in sequence from inside to outside.

6. The distributed temperature-sensitive fire detector according to claim 1, wherein the detector further comprises an audible and visual alarm (5), and the detection host (4) controls the audible and visual alarm (5) to alarm when a fire is detected.

7. A distributed temperature-sensitive fire detection system, characterized in that the detection system comprises a plurality of distributed temperature-sensitive fire detectors according to any one of claims 1 to 6 and an upper computer connected in parallel with the plurality of distributed temperature-sensitive fire detectors.

8. The distributed temperature-sensitive fire detection system according to claim 7, further comprising a fire alarm linkage module that operates and issues a fire alarm signal when the distributed temperature-sensitive fire detector detects a fire.

9. The distributed temperature-sensitive fire detector according to claim 8, wherein the detection system further comprises a switch contact signal module, and the switch contact signal module is connected to the fire alarm linkage module through a relay module or an input-output module.

10. The distributed temperature-sensitive fire detector of claim 9, wherein the switch contact signal module is a relay.

Technical Field

The invention relates to the field of fire detection, in particular to a distributed temperature-sensing fire detector and a detection system.

Background

The fire detector is a device for detecting the scene and finding out the fire in the fire-fighting automatic fire alarm system. Fire detectors are the "sense organs" of the system and function to monitor the environment for the presence or absence of a fire. Once there is fire, the characteristic physical quantity of fire, such as temperature, smoke, gas and radiation intensity, etc. are converted into electric signals, and act immediately to send alarm signals to the fire alarm controller. However, the existing fire detector cannot accurately measure the specific position of the fire and cannot measure the specific position in real time.

Disclosure of Invention

The invention aims to provide a distributed temperature-sensing fire detector and a detection system, wherein the detection system has the advantages of long measurement distance, no measurement blind area, real-time measurement and the like, and is widely applied to the fields of electric power, traffic tunnels, subways, petrifaction, dams and the like.

To achieve the above object, in one aspect, the present invention provides a distributed temperature-sensitive fire detector including:

the temperature sensing optical fiber is provided with a plurality of detection points along the extension direction thereof in sequence;

the laser emitter is used for emitting laser pulses to the access end of the temperature sensing optical fiber, the laser pulses are transmitted along the extension direction of the temperature sensing optical fiber and interact with each detection point to generate weak backward Raman scattering light and return the light along the temperature sensing optical fiber;

a wavelength division multiplexer for separating the back Raman scattered light;

the detection host is connected with the access end of the temperature sensing optical fiber through a channel, a high-speed signal acquisition unit and a weak signal processing unit are arranged in the detection host, returned back Raman scattering light separated by the wavelength division multiplexer is detected by the detection host and is processed by the high-speed signal acquisition unit and the weak signal processing unit to obtain the light intensity ratio and the return time of the back Raman scattering light of each detection point, and the temperature value and the temperature change rate of each detection point are obtained according to the relationship between the light intensity and the temperature, so that the temperature distribution information is obtained in real time.

Preferably, the backward Raman scattering light comprises temperature-sensitive anti-stokes light and temperature-insensitive stokes light, and the wavelength division multiplexer is used for separating out the temperature-sensitive anti-stokes light.

Preferably, the relationship between the light intensity and the temperature is as follows:

wherein, Δ v represents a Raman frequency shift quantity, k is a Boltzmann constant, h is a Planckian constant, T is an absolute temperature, l is a light intensity, α is an attenuation coefficient, A is a ratio of stokes light to anti-stokes light in Raman scattering light, and S (T, l) is an array containing the absolute temperature T and the light intensity l;

the detection point distance calculation formula is as follows:

wherein, L is the distance of the detection point, t is the return time of the laser, and c is the speed of light.

Preferably, the number of the temperature sensing optical fibers is not more than 8, and the total length of the 8 temperature sensing optical fibers is not more than 15 km.

Preferably, the temperature sensing optical fiber comprises an optical fiber core, a spiral steel pipe layer, a Kevlar layer, a stainless steel woven mesh layer and an outer sheath in sequence from inside to outside.

Preferably, the detector further comprises an audible and visual alarm, and the detection host controls the audible and visual alarm to give an alarm when a fire is detected.

On the other hand, the invention also discloses a distributed temperature-sensing fire detection system, which comprises a plurality of distributed temperature-sensing fire detectors and an upper computer connected with the distributed temperature-sensing fire detectors in parallel.

Preferably, the detection system further comprises a fire alarm linkage module, and when the distributed temperature-sensitive fire detector detects that a fire occurs, the fire alarm linkage module acts and sends out a fire alarm signal.

Preferably, the detection system further comprises a switch contact signal module, and the switch contact signal module is connected to the fire alarm linkage module through a relay module or an input/output module.

Preferably, the switch contact signal module is a relay.

Through the technical scheme, the invention discloses a distributed temperature-sensing fire detector and a detection system, the detector measures the temperature change distributed along a temperature-sensing optical fiber by utilizing optical time domain reflection and Raman scattering effect, has the characteristics of high measurement precision, short measurement time, long measurement distance and the like, has no blind zone in measurement, and can also carry out real-time measurement and improve the safety.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 shows a schematic diagram of a distributed temperature sensitive fire detector according to an embodiment of the invention;

fig. 2 is a schematic view illustrating a temperature-sensitive optical fiber structure of a distributed temperature-sensitive fire detector according to an embodiment of the present invention;

fig. 3 shows a schematic structural diagram of a distributed temperature-sensitive fire detection system according to an embodiment of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

Referring to fig. 1, in one aspect, the present invention provides a distributed temperature-sensing fire detector, which includes a temperature-sensing optical fiber 1, a laser emitter 2, a wavelength division multiplexer 3, and a detection host 4. Wherein, a plurality of detection points 11 are sequentially arranged on the temperature sensing optical fiber 1 along the extending direction thereof, a laser emitter 2 is used for emitting laser pulses to the access end of the temperature sensing optical fiber 1, the laser pulses are transmitted along the extending direction of the temperature sensing optical fiber and interact with each detection point 11 to generate weak back Raman scattering light and return along the temperature sensing optical fiber 1, a wavelength division multiplexer 3 is used for separating the back Raman scattering light, a detection host 4 is connected with the access end of the temperature sensing optical fiber 1 through a channel, a high-speed signal acquisition unit and a weak signal processing unit are arranged in the detection host 4, the returned back Raman scattering light separated by the wavelength division multiplexer 3 is detected by the detection host 4 and processed by the high-speed signal acquisition unit and the weak signal processing unit to obtain the light intensity ratio and the return time of the back Raman scattering light of each detection point 11 according to the relationship between the light intensity and the temperature, and obtaining the temperature value and the temperature change rate of each detection point 11, thereby obtaining the temperature distribution information in real time.

The backward Raman scattering light comprises temperature-sensitive anti-stokes light and temperature-insensitive stokes light, and the wavelength division multiplexer 3 is used for separating the temperature-sensitive anti-stokes light.

The relationship between light intensity and temperature is as follows:

wherein, Δ v represents a Raman frequency shift quantity, k is a Boltzmann constant, h is a Planckian constant, T is an absolute temperature, l is a light intensity, α is an attenuation coefficient, A is a ratio of stokes light to anti-stokes light in Raman scattering light, and S (T, l) is an array containing the absolute temperature T and the light intensity l;

the distance calculation formula of the detection point 11 is as follows:

where L is the distance of the probe 11, t is the return time of the laser, and c is the speed of light. The temperature of each detection point 11 and the distance from the detection point 11 to the detection host 4 can be detected through the two formulas, so that the temperature change of each detection point 11 can be monitored in real time, and the position of a fire occurrence point can be better known when a fire disaster or a fire disaster is about to occur.

Preferably, the number of the temperature sensitive fibers 1 is not more than 8, and the total length of the 8 temperature sensitive fibers 1 is not more than 15 km. In this embodiment, the detection host 4 is specifically provided with four channels, which correspond to the four temperature-sensing optical fibers 11 respectively. The distance of a single temperature-sensing optical fiber 11 is 2.5km, and the specific technical parameters are as follows:

measuring the distance: 2.5KM (Single channel longest 10KM)

The number of channels: 4 channel

Measuring time: 1.5 s/channel

Length of detection unit: 3m

Sampling interval: 0.4m

Positioning accuracy: 3m

Temperature setting operation temperature: 60 deg.C, 70 deg.C, 85 deg.C

Service life of the host: for 10 years

Temperature sensing optical fiber: armoured structure

Diameter of the optical fiber: 3.0mm

And (3) optical fiber interface: FC/APC

Operating the system: windows (R) Windows

A communication interface: RS485 switching value

Working temperature: a signal processing unit: (-10 to 50) DEG C, sensitive element: (-40 to 50) DEG C

Storage temperature: (-40 to 85) DEG C

Working humidity: (0-95%) R.H. no condensation

The protective performance is as follows: IP30

A working power supply: DC 24V +/-15%

Maximum operating current: 1.2A

Power supply overcurrent protection: 2.0A

Referring to fig. 2, the temperature sensing optical fiber 1 includes, in order from the inside to the outside, an optical fiber core 12, a spiral steel pipe layer 13, a kevlar layer 14, a stainless steel woven mesh layer 15, and an outer sheath 16. The detector also comprises an audible and visual alarm 5, and when the occurrence of fire is detected, the detection host 4 controls the audible and visual alarm 5 to give an alarm. The corresponding speed is improved.

Referring to fig. 3, in another aspect, the present invention further discloses a distributed temperature-sensing fire detection system, where the detection system includes a plurality of distributed temperature-sensing fire detectors and an upper computer connected in parallel to the plurality of distributed temperature-sensing fire detectors. A plurality of detectors are controlled by one upper computer to detect, and the whole transformer substation or the power system can be better monitored.

The detection system also comprises a fire alarm linkage module, and when the distributed temperature-sensing fire detector detects that a fire occurs, the fire alarm linkage module acts and sends out a fire alarm signal. The detection system further comprises a switch contact signal module, the switch contact signal module is connected to the fire alarm linkage module through the relay module or the input and output module, and specifically, the switch contact signal module is a relay.

Through the technical scheme, the invention discloses a distributed temperature-sensing fire detector and a detection system, the detector measures the temperature change distributed along a temperature-sensing optical fiber by utilizing optical time domain reflection and Raman scattering effect, has the characteristics of high measurement precision, short measurement time, long measurement distance and the like, has no blind zone in measurement, and can also carry out real-time measurement and improve the safety.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention. It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.