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Optical fibre grating sensor

A fiber grating and sensor technology, applied in the field of sensing, can solve the problems of complex equipment and high maintenance costs

Inactive Publication Date: 2009-05-06
XIAN JINHE OPTICAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, a wide light source and a precise wavelength demodulation device are used to realize it. The equipment is complex and the maintenance cost is high, which cannot meet the actual needs of many production and life.

Method used

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  • Optical fibre grating sensor
  • Optical fibre grating sensor
  • Optical fibre grating sensor

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach

[0028] image 3 It is a block diagram showing the structure of the fiber grating sensor of the first embodiment. The fiber grating sensor of the first embodiment is composed of a light source 3 , a photodetector 6 , a metal platinum-coated fiber grating 5 and an optical fiber 7 located at a measurement point for monitoring changes in methane concentration. The components are connected by optical fibers.

[0029] The detection optical signal output from the light source 3, the wavelength of the detection optical signal is not in the selective action wavelength band of the optical fiber grating 5 coated with metal platinum, and has a preset wavelength difference with it, the detection optical signal passes through the optical fiber 7 and the optical fiber The grating 5, and the intensity of the detection light signal is detected by the light detector 6. When the monitored methane concentration does not change or the change does not reach the level we care about, the wavelength ...

no. 2 approach

[0031] Fig. 4 is a block diagram showing the configuration of a fiber grating sensor according to a second embodiment. The fiber grating sensor of the second embodiment is composed of a light source 3a, a light source 3b, a light source 3n, a photodetector 6, an optical switch 8, a platinum-coated fiber grating 5 and an optical fiber 7 located at the measurement point for monitoring changes in methane concentration. The components are connected by optical fibers.

[0032]The detection optical signals of different wavelengths output from the light source 3a, the light source 3b, and the light source 3n, the wavelengths of the detection optical signals are not within the selective action wavelength band of the optical fiber grating 5 coated with metal platinum, and have different preset wavelengths difference, the optical switch 8 can select the detection optical signals of different light sources to pass through the optical fiber 7 and the fiber grating 5, and reach the optical...

no. 3 approach

[0034] Fig. 5 is a block diagram showing the configuration of a fiber grating sensor according to a third embodiment. The fiber grating sensor of the third embodiment consists of a light source 3a, a light source 3b, a light source 3n, a filter 10a, a filter 10b, a filter 10n, a photodetector 6a, a photodetector 6b, a photodetector 6n, and an optical splitter 9a , an optical splitter 9b, a metal platinum-coated optical fiber grating 5 and an optical fiber 7 located at the measurement point for monitoring the change of methane concentration. The components are connected by optical fibers.

[0035] The detection optical signals of different wavelengths output from the light source 3a, the light source 3b, and the light source 3n, the wavelengths of the detection optical signals are not within the selective action wavelength band of the fiber grating 5, and have different preset wavelength differences. The signal passes through the optical splitter 9a, then passes through the op...

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Abstract

The invention relates to a fiber grating sensor which comprises a light source, optical fibers, a probe and a fiber grating, wherein the fiber grating is mounted on the optical fibers in a measuring point, is used for monitoring the change of a methane concentration, and is plated with metal platinum. The fiber grating sensor is characterized in that a probe light signal output by a light source is injected from the incident ends of the optical fibers, and the wavelength of probe light is not in a selective function wavelength brand of the fiber grating and forms a preset wavelength difference value with the selective function wavelength band. When the monitored methane concentration changes to a quantitative value, the selective function wavelength band of the fiber grating in the measuring point at least drifts away to the preset wavelength difference value so that the selective function wavelength band is crossed and overlapped with a probe light signal wavelength brand. At the time, the wavelength band in the measuring point generates a certain reflection or dissipation of the probe light signal, the probe detects the intensity change of the probe light signal at the emergent ends so as to probe the change of the methane concentration.

Description

Technical field [0001] The invention relates to an optical fiber grating sensor, which is a sensor for detecting the change of methane gas by means of optical fiber and optical fiber grating. The device belongs to the field of sensing technology. Background technique [0002] Methane (CH4) is the main component of mine gas, natural gas, biogas and various liquid fuels. It is an important industrial raw material and daily life gas. It is also a flammable and explosive gas. The lower limit of explosion in the atmosphere is 5.3%, and the upper limit is was 15.0%. At the same time, it is also considered to be one of the most important gases for the greenhouse effect. It is reported that CH4 absorbs infrared rays 15-30 times that of CO2, accounting for 15% of the entire greenhouse contribution. The concentration of CH4 in the air increases at a rate of about 1% per year. Therefore, timely detection of the generation source, leakage source and concentration of CH4 gas plays a ve...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/17G01N21/75G01B11/16G01M3/02
Inventor 杜兵
Owner XIAN JINHE OPTICAL TECH