CN214583712U

CN214583712U - Fiber grating-based segmented temperature measurement real-time early warning device

Info

Publication number: CN214583712U
Application number: CN202121065902.5U
Authority: CN
Inventors: 于栋友; 司召鹏
Original assignee: Anshan Fenglan Technology Co ltd
Current assignee: Anshan Fenglan Technology Co ltd
Priority date: 2021-05-18
Filing date: 2021-05-18
Publication date: 2021-11-02
Anticipated expiration: 2031-05-18

Abstract

The utility model discloses a real-time early warning device of segmentation temperature measurement based on fiber grating. The device comprises a broadband light source, a circulator, a long-distance single-mode transmission optical fiber, an optical fiber grating sensor array, a coupler, a filter, a photoelectric detector and a warning lamp; when the temperature of one or more positions in the fiber grating sensor array is increased, the wavelength of light reflected by the fiber grating in the fiber grating sensor array can move towards the long wavelength direction, the filter with certain bandwidth and central wavelength can filter out the light wave in a specific waveband, and the filtered light wave is finally connected with the warning lamp through the photoelectric detector, so that the segmented real-time temperature measurement and early warning can be realized. The utility model has the advantages of can carry out the segmentation measurement to the temperature, need not complicated adjustable filter and expensive demodulating equipment, simple structure, nimble convenience, with low costs, can realize low-cost temperature real-time early warning.

Description

Fiber grating-based segmented temperature measurement real-time early warning device

Technical Field

The utility model belongs to the technical field of the fiber sensing, in particular to real-time early warning device of segmentation temperature measurement based on fiber grating.

Background

Temperature is a physical quantity which can represent the cold and hot degree of an object, plays a very important role in daily life and engineering application, and is the most common and very important measurement parameter particularly for high-end equipment such as aviation, aerospace, automobiles, aircrafts and the like during operation, so that temperature measurement and real-time monitoring are always indispensable subjects in many cases.

In the past decades, a variety of temperature sensors have been studied and used in industrial production, environmental monitoring, and medical care. The temperature sensor is a sensor capable of sensing temperature and converting the temperature into a usable output signal, the temperature sensors commonly used at present can be divided into a thermal resistor sensor and a thermocouple sensor, but with the rapid development of the optical fiber sensing technology, the optical fiber temperature sensor is a hot tide researched by people rapidly due to the unique performances of easy manufacture, small volume, low cost, firmness, durability, electromagnetic interference resistance and the like, the traditional temperature sensor can only carry out single-dimensional measurement on the temperature at a certain measuring point position, can not carry out measurement on multi-point and long-distance temperature changes, and the traditional temperature sensor has a complex structure and is expensive to manufacture, which brings a lot of difficulties to actual detection.

The optical fiber grating is a wavelength modulation type optical fiber sensor, which utilizes the photosensitivity of optical fiber materials to form a permanent optical fiber device with a periodically-changed refractive index along the axial direction of a fiber core by an ultraviolet exposure method, and the essence is to form a narrow-band reflection (or transmission) type optical filter in the fiber core, and the sensing process based on the optical fiber grating is to obtain sensing information by modulating the central wavelength of external parameters (such as stress, vibration, temperature and the like). Center lambda of fiber grating_BThe relationship with strain ε and temperature T can be simplified as a formula

According to the wavelength drift caused by the change of stress, vibration, temperature and the like, the fiber grating can be made into a fiber grating sensor for detecting various parameters such as stress, strain, pressure, vibration, temperature and the like.

Currently, the demodulation of the fiber grating is generally to measure the wavelength shift, the most common is a spectrum analyzer, the wavelength measurement range of the spectrum analyzer is wide, the resolution is high, and the spectrum analyzer can measure a tiny dependent variable, but the spectrum analyzer is large in size and expensive, is generally suitable for laboratories and is not suitable for field measurement, and some commonly used demodulation methods such as a multi-wavelength meter detection method, a matched grating detection method, a wavelength tunable light source demodulation method, a non-balanced M-Z interferometer detection method and the like exist.

SUMMERY OF THE UTILITY MODEL

The utility model aims at: in the on-site real-time monitoring process of the above-mentioned traditional fiber grating, the demodulating equipment is expensive, the complicated scheduling problem of demodulation mode, the utility model provides a simple structure, nimble convenient, with low costs, be applicable to remote measurement's a segmentation temperature measurement real-time early warning device based on fiber grating.

The utility model discloses a technical scheme who solves technical problem and take does:

a fiber grating-based segmented temperature measurement real-time early warning device is characterized by comprising a broadband light source, an optical circulator, a long-distance single-mode transmission fiber, a fiber grating sensor array, a coupler, a filter, a photoelectric detector and a warning lamp;

the optical output end of the broadband light source is connected with the port 1 of the circulator through the single-mode transmission optical fiber, the port 2 of the circulator is connected with the long-distance single-mode transmission optical fiber, the long-distance single-mode transmission optical fiber is connected with the fiber grating sensor array, the port 3 of the output port of the circulator is connected with the 1 XN coupler, the N output ports of the coupler are respectively connected with N filters with different central wavelengths and certain bandwidths, and the filter with the central wavelengths and the certain bandwidths is provided with the filter with the certain bandwidthsThe output ports of the N filters are connected with the N photoelectric detectors, and the output ends of the photoelectric detectors are connected with the warning lamp; the difference of the central wavelength of the fiber grating written in the fiber grating sensor array is not more than 0.1 nm. The bandwidth of the filter is delta lambda, and the filtering interval of the first filter is (lambda)₁，λ₁Positive delta lambda), the filtering interval of the second filter is (lambda)₁+△λ，λ₁+ 2. delta. lambda.), and by analogy, the filtering interval of the N-shaped filter plate is (lambda)₁+(n-1)△λ，λ₁+n△λ)。

The utility model has the advantages that: the temperature can be measured in sections, a complex adjustable filter and an expensive demodulation device are not needed, the structure is simple, the operation is flexible and convenient, the cost is low, and the low-cost real-time temperature early warning can be realized.

Drawings

Fig. 1 is a sectional temperature measurement real-time early warning device based on fiber bragg grating.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1, a fiber grating-based segmented temperature measurement real-time early warning device. The device comprises a broadband light source 1, an optical circulator 2, a long-distance single-mode transmission optical fiber 3, an optical fiber grating sensor array 4, a coupler 5, a filter 6, a photoelectric detector 7 and a warning lamp 8. Light emitted by the broadband light source 1 enters a port 1 of the optical circulator 2 through optical fibers, the light is output from a port 2 of the circulator 2 and is connected with an input port of a long-distance single-mode transmission optical fiber 3, an output end of the long-distance single-mode transmission optical fiber 3 is connected with an optical input end of the grating sensor array 4, the light reflected by the grating sensor array 4 is output through a port 3 of the circulator 2 and is connected with an input end of a 1 multiplied by N coupler 5, N output ports of the coupler 5 are respectively connected with N filters 6 with certain bandwidths and different central wavelengths, output ends of the N filters 6 are connected with input ends of N photoelectric detectors 7, and output ends of the N photoelectric detectors 7 are finally connected with N warning lamps 8.

The utility model discloses a system's working method does: broadband light source 1 midrangeThe light that goes out gets into 1 port of optical circulator 2 through optic fibre, light is exported from 2 ports of circulator 2 and is inputed into the optical input port of fiber grating sensor array 4 through long distance single mode transmission optic fibre 3, fiber grating sensor array 4 can reflect the input light of corresponding wavelength back to circulator 2, and carry the light that reflects back to the input port of coupler 5 through 3 ports of circulator 2, this 1 XN coupler 5 can be with input signal beam splitting N bundle, each bundle of light after the beam splitting links to each other with N filters 6 through respective tail fiber, the output light that is filtered out by filters 6 incides the input of photoelectric detector 7, photoelectric detector 7 converts this light signal into the signal of telecommunication and drives warning light 8, the warning light is with reaction temperature early warning information. When the temperature at a position or a plurality of positions in the fiber grating sensor array 4 is increased, the reflection wavelength of the fiber grating at the corresponding position influenced by the temperature changes. When the temperature rises, the wavelength of the reflected light wave will move towards the long wavelength direction, when the temperature is reduced, the wavelength of the reflected light wave will move towards the short wavelength direction, the reflected light wave enters the 1 xN coupler 5 through the 3 ports of the circulator 2, the 1 xN coupler 5 splits the reflected light into N light beams, each split light beam is connected with the N filters 6 through respective channels, the bandwidths of the N filters 6 are the same, the central wavelength linearly increases, and the No. 1 filter 6 passes through a waveband (lambda)₁，λ₁Filter No. 2, 6 pass band (λ)₁+△λ，λ₁+ 2. delta. lambda.), the No. 3-N filter 6 is increased in sequence and equivalently every other. delta. lambda. through the wave band, the device can carry out subsection early warning on the temperature, after the temperature rises, the filter 6 with the same bandwidth and different central wavelengths can effectively filter out the reflected light wave of a specific wave band, and the filtered light wave is finally connected with the warning lamp 8 through the photoelectric detector 7, so that the subsection real-time temperature measurement early warning can be realized.

The device can realize that a key technology for measuring by the fiber grating-based segmented temperature measurement real-time early warning device comprises the following steps:

1. fiber grating sensor array: fiber grating sensor arrays fabricated by means of the tower pulling technique and ultraviolet exposure can provide strong signal reflection light, all fiber grating arrays have approximately the same center wavelength and reflectivity, and the fiber grating sensor arrays can perform multi-point temperature measurement.

2. A filter plate: the filters with different central wavelengths and a certain bandwidth can effectively filter out reflected light waves of a specific waveband, and the central wavelengths of the No. 1-N filters are sequentially increased in an equivalent manner, which is the key of the device for segmented temperature measurement.

The utility model discloses a concrete embodiment, broadband light source output laser wavelength is 1550nm, single mode fiber and long distance single mode transmission optic fibre in the device, all adopt conventional single mode fiber (G.625), fiber grating width 0.15nm, reflectivity 1%, two fiber grating intervals 5m, record 300 fiber grating on the fiber grating sensor array, the coupler adopts 1 x 8 coupler, in 8 filters, first filter center wavelength 1550nm, No. 2-8 filter center wavelength increases from 1550.1nm-1550.7nm in proper order and the interval is 0.1 nm. Experimental results show that in the process of heating up 10 positions in the fiber grating sensor array, the first early warning lamp is on in the temperature range of 20 ℃ to 30 ℃, the second early warning lamp is on in the temperature range of 30 ℃ to 40 ℃, the eighth early warning lamp is on in the temperature range of 90 ℃ to 100 ℃ in sequence, and the segmented temperature measurement real-time early warning device based on the fiber grating can effectively realize segmented measurement at the interval of 10 ℃.

The basic principles and essential features of the invention have been shown and described above, and various changes and modifications may be made without departing from the spirit and scope of the invention, all of which fall within the scope of the claimed invention.

Claims

1. A fiber grating-based segmented temperature measurement real-time early warning device is characterized by comprising a broadband light source, an optical circulator, a long-distance single-mode transmission fiber, a fiber grating sensor array, a coupler, a filter, a photoelectric detector and a warning lamp; the optical output end of the broadband light source is connected with the port 1 of the circulator through the single-mode transmission optical fiber, the port 2 of the circulator is connected with the long-distance single-mode transmission optical fiber, the long-distance single-mode transmission optical fiber is connected with the fiber bragg grating sensor array, and the output port of the circulatorThe 3 port is connected with a 1 XN coupler, N output ports of the coupler are respectively connected with N filters with different central wavelengths and certain bandwidth, the central wavelengths of the filters with certain bandwidth are sequentially increased in equal proportion, the output ports of the N filters are connected with N photoelectric detectors, and the output ends of the photoelectric detectors are connected with the warning lamp; the difference of the central wavelength of the fiber grating written in the fiber grating sensor array is not more than 0.1 nm; the bandwidth of the filter is delta lambda, and the filtering interval of the first filter is (lambda)₁，λ₁Positive delta lambda), the filtering interval of the second filter is (lambda)₁+△λ，λ₁+ 2. delta. lambda.), and by analogy, the filtering interval of the N-shaped filter plate is (lambda)₁+(n-1)△λ，λ₁+n△λ)。