CN101280690A - Pressure sensor - Google Patents
Pressure sensor Download PDFInfo
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- CN101280690A CN101280690A CNA2008100143866A CN200810014386A CN101280690A CN 101280690 A CN101280690 A CN 101280690A CN A2008100143866 A CNA2008100143866 A CN A2008100143866A CN 200810014386 A CN200810014386 A CN 200810014386A CN 101280690 A CN101280690 A CN 101280690A
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- bragg grating
- grating
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- elastic tube
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Abstract
Disclosed is a pressure sensor, comprising a fiber grating, which is characterized in that the fiber grating comprises a first fiber Bragg grating and a second fiber Bragg grating and also comprises an elastic siphon with an open end and a closed end; the elastic siphon comprises a bent part and a flat part; the bent part of the elastic siphon is provided with the first fiber Bragg grating; the first fiber Bragg grating is fixedly arranged at the two ends of the bent part of the elastic siphon by a prestressing and after-fixing device; the flat part of the elastic siphon is provided with the second fiber Bragg grating; one end of the second fiber Bragg grating is connected with the first fiber Bragg grating while the other end thereof is free. The pressure sensor is mainly applied to the water pressure detection of coal mines.
Description
Technical field
The present invention relates to a kind of fibre optic compression sensor, relate in particular to a kind of optical fiber Bragg grating pressure sensor.
Background technology
Water damage is one of colliery five the Nature disasters, and water bursting in mine is the fatal disaster in colliery, and the production safety in colliery in serious threat, can cause enormous economic loss and casualties during generation.In recent years, because the extension of mining level and the expansion of limit of mining, mine production developed in depth, and the threat of flood is also serious day by day, and the task of preventing and treating is also more and more arduous, mine water disaster serious threat coal mine production safety and miner's life security.And the hydraulic pressure of mine artesian water is monitored in real time is a kind of important means of prediction and control gushing water.
What the China's coal-mine water pressure monitoring mainly used at present is the pressure sensor of electric class, but because signal of telecommunication long-distance transmissions inconvenience, need increase equipment such as many secondary meters, repeater and power supply in the down-hole, transmission cost is high and unreliable, has limited the extensive use of the type sensor.
Fiber-optic grating sensor is to make it to parameter sensitivity to be measured by the special package to fiber grating, and measure the size and the direction of parameter to be measured by the variation of optic fiber grating wavelength, for example temperature, strain, stress, pressure, displacement, speed and acceleration etc. realize that multiple spots detect, detect in real time.At present, fiber-optic grating sensor has been widely used in many scientific researches fields such as building structure, Aero-Space, marine exploration, belongs to a kind of Dynamic Non-Destruction Measurement of novelty.
Traditional fibre optic compression sensor adopts the form of equi intensity cantilever mostly, and figure one is the sketch of this structure.The sensing principle of this sensor is: ambient pressure passes to equi intensity cantilever by depression bar with pressure, cause elongation of intensity beam or shortening by the on-fixed end of pressing semi girder, thereby cause the stretching or the contraction that stick on the fiber grating on the equi intensity cantilever, and then the grating constant of change fiber grating, cause the variation of fiber grating reflection wavelength, thereby the variation of ambient pressure is learnt in the variation of the reflection wavelength by demodulating fiber bragg grating.The shortcoming of this sensor be sealing difficulty, poor repeatability, power transmission not direct, measure error is big, volume is big or the like.
Summary of the invention
The objective of the invention is for practical water damage prediction fibre optic compression sensor is provided under a kind of mine, and applicable to the on-line measurement of all fluid pressures and temperature.
This programme is realized by following technical measures: it comprises fiber grating, it is characterized in that described fiber grating is first bragg grating and second bragg grating, the elastic tube that also comprises end opening other end sealing, described elastic tube comprises sweep and straight portion, sweep at described elastic tube is provided with first bragg grating, described first bragg grating is fixedly set in elastic tube sweep two ends through after the pre-tensioning, be set with second bragg grating in the elastic tube straight portion, described second bragg grating, one end links to each other with first bragg grating, and the other end keeps free state.
The beneficial effect of this programme can be learnt according to the narration to such scheme, first bragg grating tightly is bonded at the elastic tube two ends at a given pre-Zhang Houyong epoxy glue, when extraneous fluid pressure P affacts in the elastic tube by mounting flange, make elastic tube elongation, be bonded at first bragg grating on the elastic tube and stretched and make reflected wavelength lambda
1Change, because the variable quantity of the reflection wavelength of first bragg grating and the variable quantity of outside pressure have good linear relationship, thus the variation by the demodulation first bragg grating reflection wavelength, the variation that can measure test environment pressure.Because first bragg grating is both to presser sensor in the sensor, again to responsive to temperature, and second bragg grating, one end is in free state, only to responsive to temperature, and the two is in the same environment, so deduct the amount of the wavelength change that second bragg grating causes because of variation of temperature with the wavelength of first bragg grating, can obtain first bragg grating and only change the optical grating reflection wavelength change amount that causes because of pressure, this it should be noted that wherein two gratings have temperature coefficient separately, needs to measure in advance.In this way, when calculating environment temperature, also obtained the force value that we were concerned about.Therefore the present invention has compared with prior art realized technical purpose.
The concrete characteristics of this programme also have, and at described spring tube bending straight portion front end sleeve mount pad are housed, and mount pad is provided with the protective casing that coats elastic tube.The front end of described protective casing is connected with mount pad, and the rear end is provided with the plug of band center through hole, is provided with the joints of optical fibre in described center through hole.Spring tube bending is the material with high tenacity, high-yield strength, as Bourdon tube, stainless steel etc.Described mount pad is a mounting flange.
Major part of the present invention is hydraulic pressure, the temperature pick up that Fiber Bragg Grating FBG and spring tube bending constitute, and the present invention also has some features like this: the spring tube bending that (1) pastes fiber grating is the material with high tenacity, high-yield strength; (2) pretension of the unstressed and strain grating of temperature grating in the double grating serial connection.Practical fiber bragg grating pressure sensor of the present invention, have that mining intrinsic safety, certainty of measurement height, measurement category are big, long transmission distance, simple in structure, stressed clear and definite, good reproducibility and be convenient to advantage such as installation, and it is applied widely, but the pressure and temperature information of fluid such as measurement gas, liquid has the place of flood to have broad application prospects in colliery, dam etc.Result for retrieval shows, still fiber grating and spring tube bending is not bonded together at present to make pressure sensor, and is not specifically designed to the Fibre Optical Sensor that artesian water is monitored under the colliery.Can be used for measuring the pressure of various fluids, may be used on particularly that hydraulic pressure and the temperature to artesian water detects under the coal mine, can realize remote, real-time, on-line monitoring, it provides a kind of important basis for the prediction and the control of mine water inrush, to ensureing that safety of coal mines has great importance.This fiber bragg grating pressure sensor has significant advantage: (1) is simple in structure, stressed clear and definite; (2) the enhanced sensitivity coefficient can be regulated, and the dynamic range of measurement is big; Measure when (3) can realize temperature and pressure; (4) full optical monitoring signal, transmission, the colliery essential safety.
Description of drawings
Fig. 1 is existing fibre optic compression sensor structure chart;
Fig. 2 is a fiber-optic grating sensor sectional drawing of the present invention;
Fig. 3 is the measuring system schematic diagram of sensor of the present invention;
Fig. 4 is the pressure typical measurement curve of sensor of the present invention;
Wherein: 1, first bragg grating, 2, second bragg grating, 3, elastic tube, 4, optical fiber; 5, optical connector, 6, straight tube, 7, gluing node, 8, gluing node; 9, protective casing, 10, fixed screw, 11, bend pipe stops up; 12, mounting flange, 13, connecting pipe, 14, pad; 15, plug, 16, fiber grating, 17, the beam of uniform strength; 18, depression bar, 19, optical fiber, 20, mould is strong.
The specific embodiment
Fiber Bragg Grating FBG is the optical fiber that one section refractive index cycle changes, when the light of a beamwidth spectrum passes through Fiber Bragg Grating FBG, and a branch of monochromatic light with certain wavelength of its reflected back, this wavelength changes with the variation of temperature and strain.Its formula is as follows:
Δλ＝2Δn
effΛ+2n
effΔΛ (1)
In the formula, Δ λ is an optical grating reflection wavelength change amount, n
EffBe the effective refractive index of optical fiber, Λ is a grating constant.
Do the time spent when Fiber Bragg Grating FBG is subjected to axial stress, temperature remains unchanged, and will cause the variation in grating cycle and produce elasto-optical effect, is known that by the elastomeric material mechanical knowledge pass between bragg wavelength relative displacement Δ λ and its axial strain λ ε is:
Δλ＝(1-P
e)λε (2)
Valid round light constant P wherein
eFor:
P
e＝-n
2[p
12-μ(p
11+p
12)]/2 (3)
P in the formula
11And p
12Be the bullet light constant of optical fiber, μ is a poisson's ratio, to common silica fibre, P
eBe about 0.22.
This sensor comprises elastic tube 3, mounting flange 12, protective casing 9, the joints of optical fibre 5, the first bragg gratings 1 and second bragg grating 2.One end of elastic tube 3 is welded on the mounting flange 12 in entrance pressure hole by welding procedure, and makes elastic tube 3 keep being communicated with ambient pressure, in the other end shutoff of elastic tube 3; First Fiber Bragg Grating FBG 1 is pasted the two ends of elastic tube 3, and make second Fiber Bragg Grating FBG 2 keep free state; Protective casing 9 is put and carries out sealing.Concrete structure is seen Fig. 2.
The sensing principle of sensor is, when extraneous hydraulic pressure P enters in the elastic tube 3 by the endoporus 13 of mounting flange 12, the elongation of elastic tube 3 pressurizeds makes first Fiber Bragg Grating FBG, the 1 tension elongation that is bonded in elastic tube 3 two ends (7 and 8), causes its reflected wavelength lambda
1Change.When variation of ambient temperature, also can make the reflected wavelength lambda of first Fiber Bragg Grating FBG 1 simultaneously
1Change, therefore second Fiber Bragg Grating FBG 2 that uses another root to be in free state is done temperature-compensating.
Concrete compensation way is: because second bragg grating 2 is not subjected to stress, so can not elongating or shortening and produce strain so its reflected wavelength lambda with spring tube bending 3
2Temperature influence.Because the variation of temperature amount is directly proportional with the variable quantity of the reflection wavelength of second Fiber Bragg Grating FBG 2, so according to λ
2The just variation of environment temperature as can be known of variable quantity, again because first Fiber Bragg Grating FBG 1 is in the identical environment with second Fiber Bragg Grating FBG 2, and then can obtain the variable quantity of the reflection wavelength that grating 2 causes because of variations in temperature, the variable quantity that the total variation of the reflection wavelength of grating 2 is deducted the reflection wavelength that causes because of variations in temperature just obtains the variable quantity of its reflection wavelength that causes because of pressure.Because it is also proportional that pressure changes with the variable quantity of the reflection wavelength of second Fiber Bragg Grating FBG 2, so the variable quantity of the reflection wavelength by detection fiber grating 1 and 2 just can calculate environment stress P to be measured.Its design formulas is as follows:
In the formula, λ
1Be the final reflection wavelength of first Fiber Bragg Grating FBG 1, λ
10Be the initial wavelength of first Fiber Bragg Grating FBG 1, λ
2Be the final reflection wavelength of second Fiber Bragg Grating FBG 2, λ
20Be the initial wavelength of second Fiber Bragg Grating FBG 2, K
1The temperature coefficient of first Fiber Bragg Grating FBG 1, K
2Be the temperature coefficient of second Fiber Bragg Grating FBG 2, K is the coefficient of strain of first Fiber Bragg Grating FBG 1.
Detect schematic diagram as shown in Figure 3, behind the optical fiber circulator of the light that sends by the wideband light source in the FBG (FBG) demodulator of ground through (FBG) demodulator inside, enter the preceding termination box beam split of sensing unit, the separated light in each road enters sensor and forms reflection at first Fiber Bragg Grating FBG and the second Fiber Bragg Grating FBG place, the light that reflects turns back in the FBG (FBG) demodulator along original optical path, tell the variable quantity of optic fiber grating wavelength, be admitted in the computer through data after demodulating, finally calculate the force value of measured point by formula.Typical pressure response curve as shown in Figure 4.
Claims (4)
1, a kind of pressure sensor, it comprises fiber grating, it is characterized in that described fiber grating is first bragg grating and second bragg grating, the elastic tube that also comprises end opening other end sealing, described elastic tube comprises sweep and straight portion, sweep at described elastic tube is provided with first bragg grating, described first bragg grating is fixedly set in elastic tube sweep two ends through after the pre-tensioning, be set with second bragg grating in the elastic tube straight portion, described second bragg grating, one end links to each other with first bragg grating, and the other end keeps free state.
2, pressure sensor according to claim 1 is characterized in that at described spring tube bending straight portion front end sleeve mount pad being housed, and mount pad is provided with the protective casing that coats elastic tube.
3, pressure sensor according to claim 1 is characterized in that the front end of described protective casing is connected with mount pad, and the rear end is provided with the plug of band center through hole, is provided with the joints of optical fibre in described center through hole.
4, pressure sensor according to claim 1 is characterized in that spring tube bending is a Bourdon tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008100143866A CN101280690A (en) | 2008-03-14 | 2008-03-14 | Pressure sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008100143866A CN101280690A (en) | 2008-03-14 | 2008-03-14 | Pressure sensor |
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| CN101280690A true CN101280690A (en) | 2008-10-08 |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101446206B (en) * | 2009-01-09 | 2011-01-12 | 中国安全生产科学研究院 | Mine fiber optic sensor mounting method and special jaw |
| CN101975638A (en) * | 2010-09-27 | 2011-02-16 | 山东大学 | Mining fiber Bragg grating positive pressure sensor |
| CN102322814A (en) * | 2011-09-15 | 2012-01-18 | 中国科学院半导体研究所 | Optical fiber drilling strain gauge |
| CN102359766A (en) * | 2011-09-15 | 2012-02-22 | 中国科学院半导体研究所 | Fiber body strain gauge |
| CN102519638A (en) * | 2011-11-30 | 2012-06-27 | 承德石油高等专科学校 | Fiber grating pressure testing instrument based on brim demodulation technology and testing method thereof |
| CN102587893A (en) * | 2012-03-13 | 2012-07-18 | 山东省科学院激光研究所 | Optic fiber temperature pressure sensor and probe thereof |
| CN103344317A (en) * | 2013-07-08 | 2013-10-09 | 武汉理工大学 | Non-contact type fiber bragg grating vibration sensor, and device and method for vibration measurement |
| CN104316236A (en) * | 2014-11-05 | 2015-01-28 | 中国人民解放军总参谋部工程兵科研三所 | Separated compression bar type pressure sensor |
| CN107144373A (en) * | 2017-06-16 | 2017-09-08 | 武汉理工大学 | One kind exempts from stress grating array temperature sensing optical cable and its method for sensing |
| CN109372495A (en) * | 2018-12-25 | 2019-02-22 | 马鸿彦 | It is a kind of based on the oil/gas well of pressure sensor with bit pressure force checking device |
| CN109387309A (en) * | 2017-08-08 | 2019-02-26 | 江苏弘开传感科技有限公司 | A kind of pressure transducer |
| WO2023004760A1 (en) * | 2021-07-30 | 2023-02-02 | F·欧莱特 | Temperature-compensating optical fiber strain gauge with variable range |
-
2008
- 2008-03-14 CN CNA2008100143866A patent/CN101280690A/en active Pending
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101446206B (en) * | 2009-01-09 | 2011-01-12 | 中国安全生产科学研究院 | Mine fiber optic sensor mounting method and special jaw |
| CN101975638A (en) * | 2010-09-27 | 2011-02-16 | 山东大学 | Mining fiber Bragg grating positive pressure sensor |
| CN102359766B (en) * | 2011-09-15 | 2013-06-26 | 中国科学院半导体研究所 | Fiber body strain gauge |
| CN102322814A (en) * | 2011-09-15 | 2012-01-18 | 中国科学院半导体研究所 | Optical fiber drilling strain gauge |
| CN102359766A (en) * | 2011-09-15 | 2012-02-22 | 中国科学院半导体研究所 | Fiber body strain gauge |
| CN102322814B (en) * | 2011-09-15 | 2013-12-04 | 中国科学院半导体研究所 | Optical fiber drilling strain gauge |
| CN102519638A (en) * | 2011-11-30 | 2012-06-27 | 承德石油高等专科学校 | Fiber grating pressure testing instrument based on brim demodulation technology and testing method thereof |
| CN102587893A (en) * | 2012-03-13 | 2012-07-18 | 山东省科学院激光研究所 | Optic fiber temperature pressure sensor and probe thereof |
| CN102587893B (en) * | 2012-03-13 | 2015-04-22 | 山东省科学院激光研究所 | Optic fiber temperature pressure sensor and probe thereof |
| CN103344317A (en) * | 2013-07-08 | 2013-10-09 | 武汉理工大学 | Non-contact type fiber bragg grating vibration sensor, and device and method for vibration measurement |
| CN103344317B (en) * | 2013-07-08 | 2016-08-10 | 武汉理工大学 | Non-contact optical fiber grating vibration sensor and vibration measurement device and method |
| CN104316236A (en) * | 2014-11-05 | 2015-01-28 | 中国人民解放军总参谋部工程兵科研三所 | Separated compression bar type pressure sensor |
| CN107144373A (en) * | 2017-06-16 | 2017-09-08 | 武汉理工大学 | One kind exempts from stress grating array temperature sensing optical cable and its method for sensing |
| CN109387309A (en) * | 2017-08-08 | 2019-02-26 | 江苏弘开传感科技有限公司 | A kind of pressure transducer |
| CN109372495A (en) * | 2018-12-25 | 2019-02-22 | 马鸿彦 | It is a kind of based on the oil/gas well of pressure sensor with bit pressure force checking device |
| CN109372495B (en) * | 2018-12-25 | 2022-02-08 | 马鸿彦 | Oil gas well pressure detection while drilling device based on pressure sensor |
| WO2023004760A1 (en) * | 2021-07-30 | 2023-02-02 | F·欧莱特 | Temperature-compensating optical fiber strain gauge with variable range |
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Open date: 20081008 |