CN203785779U - Dual-FBG (Fiber Bragg Grating) vibrating sensor used for liquid medium - Google Patents
Dual-FBG (Fiber Bragg Grating) vibrating sensor used for liquid medium Download PDFInfo
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- CN203785779U CN203785779U CN201320887889.0U CN201320887889U CN203785779U CN 203785779 U CN203785779 U CN 203785779U CN 201320887889 U CN201320887889 U CN 201320887889U CN 203785779 U CN203785779 U CN 203785779U
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- 239000007788 liquid Substances 0.000 title claims abstract description 25
- 239000013307 optical fiber Substances 0.000 claims abstract description 32
- 230000005540 biological transmission Effects 0.000 claims abstract description 4
- 239000000835 fiber Substances 0.000 claims description 48
- 238000007789 sealing Methods 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 3
- 238000004804 winding Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 abstract description 9
- 238000001514 detection method Methods 0.000 abstract description 4
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 230000001133 acceleration Effects 0.000 description 13
- 230000000694 effects Effects 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 230000035945 sensitivity Effects 0.000 description 6
- 238000012544 monitoring process Methods 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 2
- 238000013016 damping Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 230000006855 networking Effects 0.000 description 2
- 238000004078 waterproofing Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000001953 sensory effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
The utility model discloses a dual-FBG (Fiber Bragg Grating) vibrating sensor used for a liquid medium. The dual-FBG vibrating sensor is characterized by comprising a shell, a first FBG, a second FBG, a transmission optical fiber, a mass block, an L-shaped cantilever beam, a spring piece and a supporting fastener, wherein the first FBG and the second FBG are connected in series and are respectively connected with the shell through one end of the L-shaped cantilever beam, and the other end of the L-shaped cantilever beam is connected with the mass block; and the L-shaped cantilever beam is fixedly arranged on the shell by virtue of the spring piece. The dual-FBG vibrating sensor used for the liquid medium has self temperature compensation, and can be used for not only automatically eliminating influences of changes of environmental factors such as external temperature but also improving the detection flexibility and working band of the FBG vibrating sensor applied to vibration measurement.
Description
Technical field
The utility model relates to sensory field of optic fibre, is specifically related to a kind of double optical fiber grating vibration acceleration sensor with temperature self-compensation, and gold-plated sealing and waterproofing design, be applicable to the vibration survey of liquid medium medium-high frequency.
Background technology
Important Project equipment running status parameter is carried out the fault type of Real-Time Monitoring, timely identification equipment and assessed its usability and life-span, the disastrous fault that may occur is given warning in advance, set up accordingly corresponding safe early warning mechanism, not only can raising equipment the safe reliability of operation, can also reduce the O&M cost of equipment.Vibration is the important characterization parameter of equipment running status, vibration survey generally includes the dynamic parameters such as the displacement, speed, acceleration of vibration, acceleration has reflected the essential characteristic of object vibration, from acceleration signal, can extract the running status that relevant information such as frequency, displacement etc. can be used for assessment apparatus, therefore, vibration monitoring has a good application prospect at engineering field.
For some special applications, as the safety monitoring of the equipment such as Aero-Space, petrochemical complex, bridge dam, electric system, traditional vibration monitoring method is the most ripe with electric mensuration, but its restricted application, wiring is inconvenient and be subject to electromagnetic environment interference, especially can not be applied to the measurement of vibrating in liquid medium.
Fiber-optic grating sensor have anti-electromagnetic interference (EMI), high sensitivity, great dynamic range, size little, easily imbed, utilize multiplex technique easily to realize the advantage such as single fiber multiple spot, networking measurement, for vibration equipment monitoring, especially in liquid medium, vibration survey provides new approach.
Summary of the invention
Technical problem to be solved in the utility model is: measure problem for solving liquid medium ambient vibration, and a kind of double optical fiber grating vibration acceleration sensor for liquid medium with temperature self-compensation is provided.
The technical scheme that the utility model adopts is: a kind of double optical fiber grating vibration transducer for liquid medium, it is characterized in that, comprising: shell, the first fiber grating, the second fiber grating, Transmission Fibers, mass, L-type semi-girder, spring leaf, support securing member; Described the first fiber grating and the series connection of the second fiber grating, and be connected with shell by one end of L-type semi-girder respectively, the other end of L-type semi-girder is connected with mass, and L-type semi-girder is fixed on shell by spring leaf.
Double optical fiber grating vibration transducer for liquid medium as above, is characterized in that, described the first fiber grating and the second fiber grating are connected between shell and L-type semi-girder and impose prestress.The technique effect bringing is thus: make fiber grating on its axis, be subject to all the time the effect of the homogeneous state of stress, avoid the broadening of its reflection peak, to obtain larger measurement range.
Double optical fiber grating vibration transducer for liquid medium as above, is characterized in that, described L-type semi-girder end face is rectangular configuration, and its width is much larger than thickness.The technique effect bringing is thus: have larger bendind rigidity, crosstalk to reduce transverse axis.
Double optical fiber grating vibration transducer for liquid medium as above, is characterized in that, described spring leaf can provide certain overload protection.The technique effect bringing is thus: avoid sensor to cause device failure because of the excessive outrange of dynamic excitation, can eliminate the transverse axis cross-interference issue of sensor simultaneously.
Double optical fiber grating vibration transducer for liquid medium as above, is characterized in that, described double optical fiber grating vibration transducer adopts two fiber grating series windings, and composition double grating structure, measures the vibration in a dimension.The technique effect bringing is thus: this structure not only can realize the auto-compensation of temperature, but also can obtain the sensitivity higher than monochromatic light grid and working frequency range.
Double optical fiber grating vibration transducer for liquid medium as above, is characterized in that, described double optical fiber grating vibration transducer adopts packed by metal casing gold-plated processing, realizes waterproof and sealing.The technique effect bringing is thus: avoid the impact of liquid medium damping on double optical fiber grating vibration transducer sensing capabilities.
The beneficial effects of the utility model are: the double optical fiber grating vibration acceleration sensor for liquid medium with temperature self-compensation, not only automatically eliminate the impact that the environmental factors such as ambient temperature change, also improved detection sensitivity and the working band of optical fibre grating acceleration sensor for vibration survey; Gold-plated sealing and waterproofing design, be applicable to the vibration survey of liquid medium medium-high frequency; Wavelength-division/the sky of fiber grating point hybrid multiplex, for three-dimensional vibrating acceleration analysis and networking measurement lay the foundation.
Brief description of the drawings
Fig. 1 is the double optical fiber grating vibration transducer structural representation of the utility model embodiment.
Embodiment
In order to understand better the utility model, further illustrate content of the present utility model below in conjunction with embodiment, but content of the present utility model is not only confined to the following examples.Those skilled in the art can make various changes or modifications the utility model, and these equivalent form of values are equally within the listed claims limited range of the application.
Symbol description in accompanying drawing: 1-shell, 2-the first fiber grating, 3-the second fiber grating, 4-Transmission Fibers, 5-mass, 6-L type semi-girder, 7-spring leaf, 8-support securing member.
As shown in Figure 1, the technical scheme that the utility model adopts is: a kind of double optical fiber grating vibration transducer for liquid medium, comprising: shell 1, the first fiber grating 2, the second fiber grating 3, Transmission Fibers 4, mass 5, L-type semi-girder 6, spring leaf 7, support securing member 8 etc.; Described the first fiber grating 2 and the second fiber grating 3 are connected, and are connected with shell 1 by one end of L-type semi-girder 6 respectively, and the other end of L-type semi-girder 6 is connected with mass 5, and L-type semi-girder 6 is fixed on shell 1 by spring leaf 7.
Described the first fiber grating and the second fiber grating are connected between shell and L-type semi-girder and impose prestress, make fiber grating on its axis, be subject to all the time the effect of the homogeneous state of stress, avoid the broadening of its reflection peak, to obtain larger measurement range.
Described L-type semi-girder end face is rectangular configuration, and its width, much larger than thickness, has larger bendind rigidity, crosstalks to reduce transverse axis.
Described spring leaf can provide certain overload protection, avoids sensor to cause device failure because of the excessive outrange of dynamic excitation, can eliminate the transverse axis cross-interference issue of sensor simultaneously.
Described double optical fiber grating vibration transducer adopts two fiber grating series windings, and composition double grating structure, measures the vibration in a dimension, and this structure not only can realize the auto-compensation of temperature, but also can obtain the sensitivity higher than monochromatic light grid and working frequency range.
Described three groups of double optical fiber grating vibration transducers are combined into three-axis structure, can realize the measurement of three-dimensional vibrating acceleration.
Described double optical fiber grating vibration transducer adopts packed by metal casing gold-plated processing, realizes waterproof and sealing, avoids the impact of liquid medium damping on double optical fiber grating vibration transducer sensing capabilities.
Described branched fiber-optic grating sensor utilizes wavelength-division/sky point hybrid multiplex technology groups forming fibre-optic grating sensing network, can utilize to greatest extent the load-bearing capacity of the every passage of demodulating system, saves wiring installation cost and system cost.
Know-why of the present utility model is: optical fibre grating acceleration sensor is made up of quality-spring system, while carrying out vibration survey, sensor outer housing 1 is fixed on object under test, extraneous vibration makes, between sensor outer housing 1 and inertial mass 5, relative motion occurs, act on the first fiber grating 2 and the second fiber grating 3 by L-type semi-girder 6, make fiber grating axially be subject to the effect of stress and produce stretching or compression at it, the first fiber grating 2 and the second fiber grating 3 be alternately conversion in stretching and compressing, its fiber bragg grating center wavelength drifts about thereupon.Size and change frequency by detection fiber raster center wavelength shift can be realized the measurement to vibration acceleration.
Above-mentioned double optical fiber grating acceleration transducer, is characterized in that, the first fiber grating 2 and the second fiber grating 3 are complete same grating and arrange i.e. centre wavelength along the upper end full symmetric of L-type semi-girder 6
, temperature coefficient
and the coefficient of strain
all identical,, in the time of mass 5 vibration downwards, the first fiber grating 2 is stretched, and the second fiber grating 3 is compressed, and its wavelength variable quantity is respectively:
In formula,
be the wavelength variable quantity of the first fiber grating 2,
the wavelength variable quantity of the second fiber grating 3,
for temperature variation,
for vibrating the strain variation amount causing.Above-mentioned two formulas are added the variable quantity that can obtain temperature, and above-mentioned two formulas are subtracted each other the variable quantity that can obtain strain:
?=?
+
?/2
-
?/2
Said method has not only been realized the temperature self-compensation that vibration acceleration is measured, and also can realize the independent measurement of temperature, and have higher detection sensitivity.
Described double optical fiber grating vibration transducer can be considered single-degree-of-freedom undamped system, and its kinematical equation can be expressed as:
In formula,
yfor the displacement of mass 5 opposite shell 1;
for the displacement over the ground of shell,
;
for the quality of mass;
for system stiffness,
.
Double optical fiber grating vibration transducer is in its frequency of operation when steady operation, and the strain that fiber grating is subject to is:
Had by theory of the fiber optical
, have
?=
K
Wherein,
for wavelength variable quantity,
for the elasto-optical coefficient of fiber grating, the sensitivity coefficient of sensor is:
K=
?。
These are only embodiment of the present utility model, be not limited to the utility model, therefore, all within spirit of the present utility model and principle, any amendment of making, be equal to replacement, improvement etc., within all should being included in claim scope of the present utility model.
Claims (5)
1. for a double optical fiber grating vibration transducer for liquid medium, it is characterized in that, comprising: shell, the first fiber grating, the second fiber grating, Transmission Fibers, mass, L-type semi-girder, spring leaf, support securing member; Described the first fiber grating and the series connection of the second fiber grating, and be connected with shell by one end of L-type semi-girder respectively, the other end of L-type semi-girder is connected with mass, and L-type semi-girder is fixed on shell by spring leaf.
2. the double optical fiber grating vibration transducer for liquid medium according to claim 1, is characterized in that, described the first fiber grating and the second fiber grating are connected between shell and L-type semi-girder and impose prestress.
3. the double optical fiber grating vibration transducer for liquid medium according to claim 1, is characterized in that, described L-type semi-girder end face is rectangular configuration, and its width is much larger than thickness.
4. the double optical fiber grating vibration transducer for liquid medium according to claim 1, is characterized in that, described double optical fiber grating vibration transducer adopts two fiber grating series windings, and composition double grating structure, measures the vibration in a dimension.
5. the double optical fiber grating vibration transducer for liquid medium according to claim 1, is characterized in that, described double optical fiber grating vibration transducer adopts packed by metal casing gold-plated processing, realizes waterproof and sealing.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320887889.0U CN203785779U (en) | 2013-12-31 | 2013-12-31 | Dual-FBG (Fiber Bragg Grating) vibrating sensor used for liquid medium |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201320887889.0U CN203785779U (en) | 2013-12-31 | 2013-12-31 | Dual-FBG (Fiber Bragg Grating) vibrating sensor used for liquid medium |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103743463A (en) * | 2013-12-31 | 2014-04-23 | 国网电力科学研究院武汉南瑞有限责任公司 | Dual-FBG (Fiber Bragg Grating) vibrating sensor used for liquid medium |
| CN105203202A (en) * | 2015-11-06 | 2015-12-30 | 山东省科学院激光研究所 | Fiber grating vibration displacement sensor |
| CN104236471B (en) * | 2014-10-09 | 2016-11-16 | 中国石油化工股份有限公司 | The double FBG optical fibre vibration sensor of the Y type of coking tower hydraulic decoking on-line monitoring |
| CN107631739A (en) * | 2017-09-07 | 2018-01-26 | 西安交通大学 | Optical fiber raster vibration/stress compound sensor |
| CN110530548A (en) * | 2019-08-02 | 2019-12-03 | 西安交通大学 | A kind of fiber grating detection method and device that measurement pressure and temperature is two-parameter |
-
2013
- 2013-12-31 CN CN201320887889.0U patent/CN203785779U/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103743463A (en) * | 2013-12-31 | 2014-04-23 | 国网电力科学研究院武汉南瑞有限责任公司 | Dual-FBG (Fiber Bragg Grating) vibrating sensor used for liquid medium |
| CN104236471B (en) * | 2014-10-09 | 2016-11-16 | 中国石油化工股份有限公司 | The double FBG optical fibre vibration sensor of the Y type of coking tower hydraulic decoking on-line monitoring |
| CN105203202A (en) * | 2015-11-06 | 2015-12-30 | 山东省科学院激光研究所 | Fiber grating vibration displacement sensor |
| CN107631739A (en) * | 2017-09-07 | 2018-01-26 | 西安交通大学 | Optical fiber raster vibration/stress compound sensor |
| CN110530548A (en) * | 2019-08-02 | 2019-12-03 | 西安交通大学 | A kind of fiber grating detection method and device that measurement pressure and temperature is two-parameter |
| CN110530548B (en) * | 2019-08-02 | 2020-08-18 | 西安交通大学 | Fiber grating detection method and device for measuring pressure and temperature parameters |
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Granted publication date: 20140820 |