CN111028460A - Cavity ring-down double-channel smoke temperature fire detection device adopting time-delay frequency division technology - Google Patents
Cavity ring-down double-channel smoke temperature fire detection device adopting time-delay frequency division technology Download PDFInfo
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- CN111028460A CN111028460A CN201911237609.XA CN201911237609A CN111028460A CN 111028460 A CN111028460 A CN 111028460A CN 201911237609 A CN201911237609 A CN 201911237609A CN 111028460 A CN111028460 A CN 111028460A
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/06—Electric actuation of the alarm, e.g. using a thermally-operated switch
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
- G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
Abstract
The invention discloses a cavity ring-down dual-channel smoke temperature fire detection device based on a time delay frequency division technology, which comprises a signal generator, a 1550nm laser source, a laser modulator, an erbium-doped optical fiber amplifier, 2 x 2, optical fiber couplers I and 2 x 2 with a coupling ratio of 99:1, optical fiber couplers II and 2 x 2 with a coupling ratio of 99:1, optical fiber couplers III and 2 x 2 with a coupling ratio of 99:1, an optical fiber coupler IV with a coupling ratio of 99:1, a Marzi dislocation interferometer, an optical fiber delay line, an optical fiber isolator, an optical fiber alignment air chamber, an optical fiber combiner with an N x 1, a photoelectric detector and an oscilloscope. The invention avoids electronic components, is suitable for places with inflammability, explosiveness and high electromagnetic radiation intensity, can simultaneously meet the requirements of fire-fighting alarm products for detecting smoke and temperature, and has high sensitivity and low production and maintenance cost.
Description
Technical Field
The invention belongs to the technical field of fire detection devices and methods, and particularly relates to a cavity ring-down double-channel smoke temperature fire detection device based on a time delay frequency division technology.
Background
At present, fire detectors for automatic fire alarm in domestic and foreign markets mainly comprise temperature-sensitive fire detectors, smoke-sensitive fire detectors and composite photoelectric smoke-sensitive fire detectors. The temperature-sensing fire detector comprises an electronic point type constant-temperature fire detector, a cable type linear constant-temperature fire detector, an electronic differential constant-temperature fire detector, a linear fiber bragg grating temperature-sensing fire detector and the like; the smoke fire detector comprises a photoelectric smoke detector, an ion smoke detector and an infrared beam laser line type smoke detector.
The existing smoke fire detector has the following problems: 1. because of the existence of electric signals, potential safety hazards exist in places which are inflammable and explosive and have high electromagnetic radiation intensity; 2. electronic components are easy to age and wet, and further false alarm and even failure are caused; 3. the detector has a complex structure and higher later maintenance cost; radioactive elements are adopted as ion sources, so that the method is unsafe; 5. the detector is easily interfered by infrared light and ultraviolet light, and a detection light beam is easily blocked, so that higher false alarm is generated; 6. the fire detection system is required to be matched with an expensive fire detection controller commonly called a host.
The existing temperature-sensing fire detector has the following problems: 1. because of the existence of electric signals, potential safety hazards exist in places which are inflammable and explosive and have high electromagnetic radiation intensity; 2. electronic components are easy to age and wet, and further false alarm and even failure are caused; 3. the linear temperature-sensing detector has poor fire locating performance and cannot be used repeatedly; 4. the alarm action temperature range is wide, so that the sensitivity is low; 5. the linear fiber bragg grating temperature-sensing fire detector has very high use cost and maintenance cost, and is difficult to accept by general users; 6. the fire detection system is required to be matched with an expensive fire detection controller commonly called a host.
The problems of the prior combined photoelectric smoke-sensing and temperature-sensing fire detector are as follows: 1. because of the existence of electric signals, potential safety hazards exist in fields with high intensity of inflammable, explosive and electromagnetic radiation; 2. electronic components are easy to age and wet, and further false alarm and even failure are caused; 3. the temperature sensing element is horizontally arranged, is easily covered by dust and winged insects to cause failure or misinformation, and the smoke chamber is not easy to disassemble and remove dust; 4. the batteries need to be replaced regularly, which is inconvenient; 5. networking and remote monitoring cannot be achieved.
Disclosure of Invention
The invention solves the technical problem of providing a cavity ring-down dual-channel smoke temperature fire detection device adopting a time delay frequency division technology, which can simultaneously sense and measure smoke concentration and temperature by utilizing an optical fiber cavity ring-down technology, and effectively separates ring-down signals in a time domain and distinguishes two physical parameters in a frequency domain by utilizing an optical fiber delay line through the time delay frequency division technology so as to achieve the purpose of dual-channel sensing and effectively avoid the defects of an electronic fire detection device.
The invention adopts the following technical scheme for solving the technical problems, and the cavity ring-down double-channel smoke temperature fire detection device of the time delay frequency division technology is characterized by comprising a signal generator, a 1550nm laser source, a laser modulator, an erbium-doped optical fiber amplifier, 2 x 2, optical fiber couplers I and 2 x 2 with a coupling ratio of 99:1, optical fiber couplers II and 2 x 2 with a coupling ratio of 99:1, optical fiber couplers III and 2 x 2 with a coupling ratio of 99:1, an optical fiber coupler IV with a coupling ratio of 99:1, a Mare dislocation interferometer, an optical fiber delay line, an optical fiber isolator, an optical fiber alignment air chamber, an optical fiber combiner with N x 1, a photoelectric detector and an oscilloscope; the laser modulator is connected with an erbium-doped optical fiber amplifier and an optical fiber coupler I with a coupling ratio of 2 x 2 to 99:1 sequentially through optical fibers, the signal generator and the 1550nm laser source are respectively connected with the laser modulator through electric wires, and the erbium-doped optical fiber amplifier is made of 2m erbium-doped optical fibers and 980nm pump light sources through an 980/1550 wavelength division multiplexer; the optical fiber delay line is used for distinguishing the ring-down curve of each parameter from the time domain; the optical fiber ring cavity I enters from the low splitting ratio end of the optical fiber coupler I, is sequentially connected with the Marzier dislocation interferometer and the optical fiber coupler II through a single-mode optical fiber, and then is output to enter the optical fiber beam combiner of N x 1 through the low splitting ratio end of the optical fiber coupler II, and the high splitting ratio end of the optical fiber coupler I is connected with the high splitting ratio end of the optical fiber coupler II in a fusion mode; the fiber ring cavity II enters from the low-splitting ratio end of the fiber coupler III through the fiber coupler I, the fiber delay line and the fiber isolator in sequence, is connected with the fiber alignment air chamber and the fiber coupler IV through a single-mode fiber in sequence, and then is output from the low-splitting ratio end of the fiber coupler IV to enter the fiber combiner of N1, the high-splitting ratio end of the fiber coupler III is connected with the high-splitting ratio end of the fiber coupler IV in a fusion mode, amplified pulse laser enters the fiber ring cavity I and the fiber ring cavity II through the fiber coupler I and the fiber coupler III in a primary-level splitting mode, and the fiber isolator is inserted between the two fiber ring cavities and is used for preventing reflected light of the fiber end face of the next fiber ring cavity from influencing sensing measurement of the previous fiber ring cavity; the optical fiber beam combiner is connected with the photoelectric detector through a single-mode optical fiber, and the photoelectric detector is connected with the oscilloscope through an electric wire and used for converting optical signals into electric signals by the photoelectric detector and displaying the electric signals on the oscilloscope; the light entering each optical fiber ring cavity is respectively 100% and 99%, the pulse laser intensity is basically equal, the detection capability of the high-speed photoelectric detector is conveniently matched, the sensing of the temperature and the smoke concentration is separated on the time domain through an optical fiber delay line between the optical fiber ring cavities, the cavity lengths of the two optical fiber ring cavities are different, the carrying frequencies of output signals of the two optical fiber ring cavities are different, the output signals are effectively separated in the frequency domain, the Fourier transform is carried out on the output signals, the change of the temperature and the smoke concentration is measured through the transformed 3dB bandwidth, and the simultaneous detection of the temperature and the smoke concentration is further realized.
Compared with the prior art, the invention has the following advantages: 1. the invention provides a cavity ring-down double-channel smoke temperature fire detection device based on a time delay frequency division technology. 2. The invention realizes the measurement and sensing of the temperature by utilizing the double-malposition interference structure of the eupatorium. 3. The invention realizes the sensing measurement of the smoke concentration by aligning the optical fiber to the air chamber. 4. The whole sensing structure adopts a time-delay frequency division technology, so that ring-down signals are effectively separated in a frequency domain to distinguish different physical quantities in a time domain, and the purpose of simultaneously measuring and sensing temperature and smoke concentration is achieved. 5. The invention avoids electronic components, is suitable for places with inflammability, explosiveness and high electromagnetic radiation intensity, can simultaneously meet the requirements of fire-fighting alarm products for detecting smoke and temperature, and has high sensitivity and low production and maintenance cost.
Drawings
Fig. 1 is a schematic diagram of the optical path of the present invention.
Description of the drawings: 1. signal generator, 2, 1550nm laser source, 3, laser modulator, 4, erbium-doped optical fiber amplifier, 511Optical fiber coupler I, 512Optical fiber two-coupler II, 521Fibre-optical coupler III, 522The optical fiber coupler comprises optical fiber couplers IV and 6, a Marzier dislocation interferometer 7, an optical fiber delay line 8, an optical fiber isolator 9, an optical fiber alignment air chamber 10, an optical fiber combiner 11, a photoelectric detector 12, an oscilloscope 13, an electric wire 14 and a single mode optical fiber.
FIG. 2 is a block diagram of a Marek's interferometer.
FIG. 3 is a block diagram of an optical fiber alignment gas cell.
Detailed Description
The present invention is described in further detail below with reference to examples, but it should not be construed that the scope of the above subject matter of the present invention is limited to the following examples, and that all the technologies realized based on the above subject matter of the present invention belong to the scope of the present invention.
The details of the present invention are described in detail with reference to the accompanying drawings. A cavity ring-down double-channel smoke temperature fire detection device based on a time delay frequency division technology is characterized in that a cavity ring-down double-channel sensing structure is built, as shown in figure 1, the cavity ring-down double-channel sensing structure comprises a signal generator 1, a 1550nm laser source 2, a laser modulator 3, erbium-doped optical fiber amplifiers 4 and 2 x 2 and an optical fiber coupler I5 with a coupling ratio of 99:1112 x 2, 99:1 coupling ratio of the fiber coupler II 5122 x 2, coupling ratio 99:1 fiber coupler III 5212 x 2, coupling ratio 99:1 fiber coupler IV 522The system comprises a Marzier dislocation interferometer (temperature sensing unit) 6, an optical fiber delay line 7, an optical fiber isolator 8, an optical fiber alignment air chamber (smoke concentration sensing unit) 9, an optical fiber beam combiner 10 of Nx 1, a photoelectric detector 11, an oscilloscope 12, an electric wire 13 and an optical fiber 14; the erbium-doped fiber amplifier 4 is made of a section of 2m erbium-doped fiber and a 980nm pump light source through an 980/1550 wavelength division multiplexer; the fibre-optic delay line 7 serving to temporally separate two parametersA ring-down curve; the optical fiber ring cavity I and the optical fiber ring cavity II enter from the low-splitting ratio end of each optical fiber ring cavity optical fiber coupler I and the optical fiber coupler III, and are sequentially connected with a sensing unit (a Markov dislocation interferometer 6 or an optical fiber alignment air chamber 9), the optical fiber coupler II and the optical fiber coupler IV of each optical fiber ring cavity by a single mode optical fiber, and are output to enter the optical fiber beam combiner 10 through the low-splitting ratio end of the optical fiber coupler II and the optical fiber coupler IV of each optical fiber ring cavity; the signal generator 1, the laser modulator 3 and the 1550nm laser source 2 are respectively connected through an electric wire 13, the photoelectric detector 11 and the oscilloscope 12 are connected through the electric wire 13, and other connections are all connected through a single-mode optical fiber 14; the amplified pulse laser enters each optical fiber ring cavity through first-stage light splitting of the optical fiber coupler I and the optical fiber coupler III; the sensing unit is embodied as a dislocated optical fiber interference structure and an optical fiber alignment air chamber, and other structures can be added to realize measurement of other physical quantities.
In the dual-channel fiber ring cavity ring-down sensing system, pulse laser amplified by an erbium-doped fiber amplifier (EDFA) is divided into two paths through a 2 x 2 and 99:1 fiber coupler I, wherein a 1% power output port enters the fiber ring cavity I, a single-mode fiber is connected with a sensing unit (Marzis dislocation interferometer) and a fiber coupler II in sequence and is output through a 1% end of the fiber coupler II, and the two fiber couplers I and the 99% power ports of the fiber coupler II are welded together; the 99% power output end of the optical fiber coupler I enters the optical fiber coupler III of the optical fiber ring cavity II through a section of optical fiber delay line and an optical fiber isolator, and is output through the sensing unit (optical fiber alignment air chamber) and the optical fiber coupler IV as the same as the optical fiber ring cavity I; and the outputs of the two optical fiber ring cavities are connected into the optical fiber beam combiner of N x 1, and then are converted into electric signals by the photoelectric detector and displayed on an oscilloscope. The light entering each optical fiber ring cavity is respectively 100% and 99%, the pulse laser intensity is basically equal, and the detection capability of the high-speed photoelectric detector is conveniently matched. The fiber delay line between the fiber ring cavities separates the sensing of temperature and smoke concentration in time domain; and the cavity lengths of the two optical fiber ring cavities are different, which can cause different carrying frequencies of the output signals of the optical fiber ring cavities, so that the output signals are effectively separated in the frequency domain. Fourier transform is carried out on the output signal, and the change of the temperature and the smoke concentration is measured by using the transformed 3dB bandwidth, so that the simultaneous detection of the temperature and the smoke concentration is realized. In addition, the optical fiber ring cavity ring-down dual-channel sensing device can meet the requirements of different fields by cascading more optical fiber sensing ring cavities.
The foregoing embodiments illustrate the principles, principal features and advantages of the invention, and it will be understood by those skilled in the art that the invention is not limited to the foregoing embodiments, which are merely illustrative of the principles of the invention, and that various changes and modifications may be made therein without departing from the scope of the principles of the invention.
Claims (1)
1. A cavity ring-down double-channel smoke temperature fire detection device based on a time delay frequency division technology is characterized by comprising a signal generator, a 1550nm laser source, a laser modulator, an erbium-doped optical fiber amplifier, 2 x 2, optical fiber couplers I and 2 x 2 with a coupling ratio of 99:1, optical fiber couplers II and 2 x 2 with a coupling ratio of 99:1, optical fiber couplers III and 2 x 2 with a coupling ratio of 99:1, an optical fiber coupler IV with a coupling ratio of 99:1, a malposition interferometer, an optical fiber delay line, an optical fiber isolator, an optical fiber alignment air chamber, an optical fiber combiner with N x 1, a photoelectric detector and an oscilloscope; the laser modulator is connected with an erbium-doped optical fiber amplifier and an optical fiber coupler I with a coupling ratio of 2 x 2 to 99:1 sequentially through optical fibers, the signal generator and the 1550nm laser source are respectively connected with the laser modulator through electric wires, and the erbium-doped optical fiber amplifier is made of 2m erbium-doped optical fibers and 980nm pump light sources through an 980/1550 wavelength division multiplexer; the optical fiber delay line is used for distinguishing the ring-down curve of each parameter from the time domain; the optical fiber ring cavity I enters from the low splitting ratio end of the optical fiber coupler I, is sequentially connected with the Marzier dislocation interferometer and the optical fiber coupler II through a single-mode optical fiber, and then is output to enter the optical fiber beam combiner of N x 1 through the low splitting ratio end of the optical fiber coupler II, and the high splitting ratio end of the optical fiber coupler I is connected with the high splitting ratio end of the optical fiber coupler II in a fusion mode; the fiber ring cavity II enters from the low-splitting ratio end of the fiber coupler III through the fiber coupler I, the fiber delay line and the fiber isolator in sequence, is connected with the fiber alignment air chamber and the fiber coupler IV through a single-mode fiber in sequence, and then is output from the low-splitting ratio end of the fiber coupler IV to enter the fiber combiner of N1, the high-splitting ratio end of the fiber coupler III is connected with the high-splitting ratio end of the fiber coupler IV in a fusion mode, amplified pulse laser enters the fiber ring cavity I and the fiber ring cavity II through the fiber coupler I and the fiber coupler III in a primary-level splitting mode, and the fiber isolator is inserted between the two fiber ring cavities and is used for preventing reflected light of the fiber end face of the next fiber ring cavity from influencing sensing measurement of the previous fiber ring cavity; the optical fiber beam combiner is connected with the photoelectric detector through a single-mode optical fiber, and the photoelectric detector is connected with the oscilloscope through an electric wire and used for converting optical signals into electric signals by the photoelectric detector and displaying the electric signals on the oscilloscope; the light entering each optical fiber ring cavity is respectively 100% and 99%, the pulse laser intensity is basically equal, the detection capability of the high-speed photoelectric detector is conveniently matched, the sensing of the temperature and the smoke concentration is separated on the time domain through an optical fiber delay line between the optical fiber ring cavities, the cavity lengths of the two optical fiber ring cavities are different, the carrying frequencies of output signals of the two optical fiber ring cavities are different, the output signals are effectively separated in the frequency domain, the Fourier transform is carried out on the output signals, the change of the temperature and the smoke concentration is measured through the transformed 3dB bandwidth, and the simultaneous detection of the temperature and the smoke concentration is further realized.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114646340A (en) * | 2022-03-16 | 2022-06-21 | 华中科技大学 | Multiplexing FLRD sensor based on wide-spectrum continuous light and multi-parameter detection method |
| CN116328243A (en) * | 2023-02-07 | 2023-06-27 | 国网湖北省电力有限公司技术培训中心 | Dormitory local fireproof method and device based on optical fiber sensor |
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