CN116222849A - Optical fiber pressure sensor and sensing system - Google Patents
Optical fiber pressure sensor and sensing system Download PDFInfo
- Publication number
- CN116222849A CN116222849A CN202310154333.9A CN202310154333A CN116222849A CN 116222849 A CN116222849 A CN 116222849A CN 202310154333 A CN202310154333 A CN 202310154333A CN 116222849 A CN116222849 A CN 116222849A
- Authority
- CN
- China
- Prior art keywords
- elastic tube
- optical fiber
- pressure sensor
- fiber
- bragg grating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 107
- 239000000835 fiber Substances 0.000 claims abstract description 90
- 238000007789 sealing Methods 0.000 claims abstract description 32
- 229910052751 metal Inorganic materials 0.000 claims description 42
- 239000002184 metal Substances 0.000 claims description 42
- 230000005540 biological transmission Effects 0.000 claims description 33
- 238000012545 processing Methods 0.000 claims description 25
- 238000001514 detection method Methods 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 238000000034 method Methods 0.000 description 11
- 230000035945 sensitivity Effects 0.000 description 11
- 230000003287 optical effect Effects 0.000 description 9
- 230000008569 process Effects 0.000 description 7
- 230000009471 action Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000013535 sea water Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000008602 contraction Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 230000005483 Hooke's law Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 230000002277 temperature effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
- G01L1/246—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre using integrated gratings, e.g. Bragg gratings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
- G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
Abstract
The invention provides a push-pull type high-precision optical fiber pressure sensor and a sensing system, and relates to the technical field of pressure sensors. The optical fiber pressure sensor comprises a shell, a first elastic tube and a second elastic tube, wherein the first elastic tube and the second elastic tube are distributed along the expansion direction of the first elastic tube, a sealing plate is arranged between the first elastic tube and the second elastic tube, one ends of the first elastic tube and the second elastic tube, which are close to each other, are respectively abutted to two sides of the sealing plate and sealed by the sealing plate, and one ends of the first elastic tube and the second elastic tube, which are far away from each other, are fixedly connected with the shell; the first fiber Bragg grating is fixed in the first elastic tube along the expansion direction, and the second fiber Bragg grating is fixed in the second elastic tube along the expansion direction. The invention combines two elastic tubes with two fiber Bragg gratings to form a push-pull structure so as to offset the influence of environmental factors such as submarine temperature and the like and the instability of active devices such as light sources and the like in a light path, and is suitable for submarine environments.
Description
Technical Field
The invention relates to the technical field of pressure sensors, in particular to a push-pull type high-precision optical fiber pressure sensor and a sensing system.
Background
The submarine pressure can reflect the physical characteristics of the ocean and is a key test parameter in tsunami monitoring and early warning. The measurement performance of the submarine pressure sensor directly determines the accuracy of ocean depth positioning, so that the accuracy of tsunami monitoring and early warning is affected.
Compared with the traditional electrical sensing technology, the optical fiber sensing technology has the advantages of being intrinsic, passive, high in sensitivity, small in size, large in measuring range and the like, and is more suitable for marine environments with long-term power supply difficulty.
However, the ocean environment is complex and has high interference, the existing optical fiber pressure sensor is easily interfered by environmental factors such as submarine temperature, and the instability of active devices such as light sources in an optical path leads to lower accuracy, poorer anti-interference performance and difficult adaptation to the submarine environment.
Disclosure of Invention
Aiming at the technical problems, the invention provides an optical fiber pressure sensor and a sensing system, wherein a push-pull structure is formed by arranging two elastic tubes and matching two optical fiber Bragg gratings, so that the influence of environmental factors such as submarine temperature and the like and the influence of instability and the like of active devices such as a light source and the like in an optical path are counteracted, and the optical fiber pressure sensor and the sensing system are suitable for submarine environments. The technical scheme is as follows:
the invention particularly provides an optical fiber pressure sensor which comprises a shell, a first elastic tube and a second elastic tube, wherein the first elastic tube and the second elastic tube are arranged along the extending and retracting directions of the first elastic tube and the second elastic tube, a sealing plate is arranged between the first elastic tube and the second elastic tube, one ends, close to each other, of the first elastic tube and the second elastic tube are respectively abutted to two sides of the sealing plate, the ends, close to each other, of the first elastic tube and the second elastic tube are sealed by the sealing plate, and the ends, far away from each other, of the first elastic tube and the second elastic tube are fixedly connected with the shell; the first fiber Bragg grating is fixed in the first elastic tube along the expansion direction, and the second fiber Bragg grating is fixed in the second elastic tube along the expansion direction.
Further, the first elastic tube and the second elastic tube are both metal corrugated tubes.
Further, the first elastic tube and the second elastic tube are coaxially fixed in the housing.
Further, the sealing plate has a diameter equal to the diameter of the first elastic tube/second elastic tube.
Further, the sealing plate is an aluminum sheet.
Further, the first fiber Bragg grating is stuck and fixed in the first elastic tube, and the second fiber Bragg grating is stuck and fixed in the second elastic tube.
Further, the first fiber Bragg grating and the second fiber Bragg grating are the same and etched on the same optical fiber, one end of the optical fiber is fixed at the end part of the first elastic tube, and the other end of the optical fiber penetrates through the sealing plate and is fixed at the end part of the second elastic tube.
The present invention also provides a pressure sensing system comprising: the optical fiber pressure sensor comprises a light source, a processing module and the optical fiber pressure sensor; the optical fiber of the optical fiber pressure sensor is connected with the light source; the processing module is connected with the optical fiber pressure sensor, receives signals of the optical fiber pressure sensor, and outputs wavelength values according to the signals.
Further, the system also comprises a transmission module, wherein the transmission module comprises a first transmission optical fiber and a second transmission optical fiber which are used for transmitting signals, one end of the first transmission optical fiber is connected with the light source, and the other end of the first transmission optical fiber is connected with the optical fiber of the optical fiber pressure sensor; one end of the second transmission optical fiber is connected with the optical fiber pressure sensor, and the other end of the second transmission optical fiber is connected with the processing module.
Further, the processing module comprises a photoelectric detection component, a wavelength demodulation component and a signal acquisition and processing component; the optical fiber pressure sensor is connected with the photoelectric detection assembly through the second transmission optical fiber; the photoelectric detector, the wavelength demodulation component and the signal acquisition and processing component are sequentially connected and transmit signals, and the signal acquisition and processing component outputs wavelength values according to the signals.
The invention has the beneficial effects that:
firstly, the invention is provided with a pair of first elastic tube and second elastic tube, and an optical fiber Bragg grating is respectively stuck on the first elastic tube and the second elastic tube, so that a push-pull structure is formed, and the push-pull structure can directly offset the influence of the seabed temperature by utilizing the symmetry of the push-pull structure, and additional temperature compensation arrangement is not needed. And the push-pull structure can also counteract the instability of active devices such as light sources and the like in the light path and the interference of other factors. In addition, the combination of the two elastic tubes and the two groups of fiber Bragg gratings is connected through a sealing plate to form a push-pull structure, so that the sensitivity is further doubled, and finally the fiber sensor has strong anti-interference performance, strong stability and high sensitivity and is suitable for a submarine complex environment.
Secondly, the elastic tube is arranged as the metal corrugated tube, and the sensitivity of the optical fiber pressure sensor is further improved by utilizing the low axial elasticity coefficient of the metal corrugated tube and the wavelength-strain sensitivity of the optical fiber Bragg grating.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that are required to be used in the description of the embodiments of the present invention will be briefly described below.
FIG. 1 is a schematic diagram of the overall structure of a fiber optic pressure sensor;
FIG. 2 is a front view of a fiber optic pressure sensor;
FIG. 3 is a schematic diagram of a fiber optic pressure sensing system.
The same reference numbers will be used throughout the drawings to refer to identical or similar parts or components.
10. A housing; 20. a metal bellows; 301. a first fiber Bragg grating; 302. a second fiber Bragg grating; 31. an optical fiber; 40. and (5) sealing the plate.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings. Examples of the embodiments are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements throughout, or elements having like or similar functionality. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
In the description of the present specification, the terms "embodiment," "present embodiment," "in one embodiment," and the like, if used, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples; furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
In the description of the present specification, the terms "connected," "mounted," "secured," "disposed," "having," and the like are to be construed broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.
In the description of this specification, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In one embodiment, as shown in FIG. 1, a fiber optic pressure sensor includes a housing 10, two elastomeric tubes, and two fiber optic Bragg gratings. The two elastic tubes are a first elastic tube and a second elastic tube, respectively, and the two fiber bragg gratings are a first fiber bragg grating 301 and a second fiber bragg grating 302, respectively. The first elastic tube and the second elastic tube are arranged along the extending direction of the first elastic tube, a sealing plate 40 is arranged between the first elastic tube and the second elastic tube, one ends of the first elastic tube and the second elastic tube, which are close to each other, are respectively abutted to two sides of the sealing plate 40 and sealed by the sealing plate 40, and one ends of the first elastic tube and the second elastic tube, which are far away from each other, are fixedly connected with the shell 10. So that the ends of the two elastic tubes, which are adjacent to each other, can be moved along with the sealing plate 40, and the two elastic tubes can be respectively stretched and compressed.
A first fiber bragg grating 301 is fixed in the first elastic tube along the expansion and contraction direction, and a second fiber bragg grating 302 is fixed in the second elastic tube along the expansion and contraction direction. When the two elastic tubes are respectively lengthened and shortened along with the sealing plate 40, the two fiber bragg gratings can be respectively and synchronously deformed along with the corresponding elastic tubes.
When the optical fiber pressure sensor is placed on the seabed, when seawater on the seabed enters a certain elastic tube, the sealing plate 40 moves to a pressure balance position under the action of water pressure, the sealing plate 40 drives the two elastic tubes to respectively stretch and compress, the optical fiber Bragg gratings fixed on the two elastic tubes can synchronously stretch or compress along with the corresponding elastic tubes respectively, the variation of the wavelength of the optical fiber Bragg gratings is obtained, and the pressure of the seabed can be obtained according to the wavelength demodulation method of the optical fiber Bragg gratings. Compared with the common fiber Bragg grating pressure sensing, the fiber pressure sensor of the embodiment utilizes two fiber Bragg gratings to form a push-pull structure, wherein one fiber Bragg grating stretches towards one side, the other fiber Bragg grating is compressed towards the same side, namely, the two fiber Bragg gratings move along the same direction.
In practical applications, besides the wavelength change of the fiber bragg grating caused by the submarine water pressure, the submarine temperature also affects the wavelength of the fiber bragg grating. When the submarine temperature influences the moving amount of the fiber bragg gratings, the two fiber bragg gratings are located at the same environment temperature, the influence of the ambient temperature change on the wavelength movement of the two fiber bragg gratings is consistent, namely, the temperature can cause the two fiber bragg gratings to synchronously extend or shorten the same length, one ends of the two fiber bragg gratings, which are far away from each other, are fixed on the shell 10 along with the two elastic tubes, and one ends of the two fiber bragg gratings, which are close to each other, can move, so that one ends of the two fiber bragg gratings, which are close to each other, can generate deformation in opposite directions under the influence of the temperature, and further a pair of opposite deformation counteracts each other. Therefore, the optical fiber pressure sensor can offset the influence of the seabed temperature factor, avoid the influence of temperature on the accuracy of the optical fiber pressure sensor, reduce errors and improve the anti-interference capability of the optical fiber pressure sensor.
Besides, besides the influence of the submarine temperature, the instability of active devices such as a light source in the light path of the optical fiber pressure sensor and other physical quantities which possibly cause the wavelength fluctuation of the two optical fiber Bragg gratings from the outside can be counteracted by the symmetrical push-pull structure of the optical fiber pressure sensor in the embodiment, so that the optical fiber pressure sensor in the embodiment has strong anti-interference performance and submarine environment adaptability compared with other optical fiber pressure sensors.
In addition, compared with the common fiber bragg grating sensor, the fiber bragg grating sensor in the embodiment has the advantages that under the action of the submarine water pressure, the two fiber bragg gratings move in the same direction, namely the wavelength movement amount of the two fiber bragg gratings is more than that of one fiber bragg grating, and the sensitivity of the fiber bragg grating sensor is improved.
In one embodiment, as shown in fig. 1 and 2, the first elastic tube and the second elastic tube are both metal bellows 20. Compared with the optical fiber, the metal corrugated tube 20 has small elastic modulus (about 50N/mm), and the optical fiber Bragg grating is tightly adhered to the metal corrugated tube 20, so that the overall effective elastic modulus of the optical fiber Bragg grating and the metal corrugated tube 20 is reduced, deformation is easier to generate under certain external pressure, the pressure sensitivity of the optical fiber Bragg grating is increased, and the sensitivity of the optical fiber pressure sensor is further improved.
The deformation transmission mechanism between the metal bellows 20 and the fiber bragg grating is as follows: the fiber bragg grating is tightly adhered to the metal bellows 20 to form a whole, and when external pressure is applied to the metal bellows 20, the fiber bragg grating and the metal bellows 20 deform synchronously.
Specifically, the metal bellows 20 has a small modulus of elasticity in the axial direction, so the metal bellows 20 can be regarded as a spring which axially follows hooke's law, axial strain amount ε z The relation between the pressure and the external pressure P to which the pressure is applied is epsilon z = - (PA)/(KL), where a is the effective area, K is the elastic coefficient, and L is the length of the metal bellows 20. Thus, the coefficient of elasticity, length and effective area of the bellows 20 are selected, and the deformation-pressure relationship coefficient can be determined.
Further, the wavelength shift amount Δλ of the fiber bragg grating B And axial strain epsilon z Proportional to the formula Deltalambda B /λ B ＝(1-P e )ε z Wherein lambda is B Is the initial wavelength, P, of the fiber Bragg grating e Is the effective elasto-optical coefficient of the fiber bragg grating. When external pressure is applied to the fiber Bragg grating to generate axial strain, the center wavelength of the fiber Bragg grating is shifted by delta lambda B . The deformation of the fiber Bragg grating can be obtained by measuring the central wavelength variation.
In one embodiment, the first elastic tube and the second elastic tube are completely identical corrugated metal tubes, and the two corrugated metal tubes 20 are coaxially fixed in the housing 10, so that the elastic coefficients, the lengths and the effective areas of the two corrugated metal tubes 20 are identical, the axial strain amounts of the two corrugated metal tubes 20 are identical to the relation of the external pressure, and the total axial strain amount calculated according to the optical fiber pressure sensor is twice the axial strain amount of the single corrugated metal tube 20. And (5) taking half of the total axial strain into a relation between the axial strain and the external pressure to obtain an external pressure value. Compared with two metal bellows 20 which are not identical, it is more recommended that the pair of identical metal bellows 20 of the present embodiment calculate the external pressure, which is convenient for practical application. In other embodiments, the two metal bellows 20 may be not identical, and the pressure value may be obtained by adjusting a calculation formula according to the actual parameters of the metal bellows 20.
Further, the optical fiber pressure sensor comprises an optical fiber 31, the optical fiber 31 sequentially passes through two elastic tubes, and the first optical fiber Bragg grating 301 and the second optical fiber Bragg grating 302 are identical and etched on the same optical fiber 31. The two identical fiber bragg gratings have the same initial wavelength and the same effective elastic coefficient, and are matched with the two identical metal bellows 20, so that compared with the common fiber pressure sensor of the single metal bellows 20 fiber bragg grating, the sensitivity of the dual metal bellows 20 fiber bragg grating pressure sensor of the embodiment is doubled. In other embodiments, the two fiber bragg gratings may not be identical, and the pressure value may be obtained by adjusting a calculation formula according to actual parameters of the fiber bragg gratings.
In other embodiments, the first fiber bragg grating 301 and the second fiber bragg grating 302 may be etched on two optical fibers, respectively, where one end of each of the two optical fibers is fixedly connected to the elastic tube, and the other end is fixedly connected to the sealing plate 40. The two optical fibers can be set to be simpler in calculation of the pressure with the same size, can also be set to be different in size, and can also obtain the submarine pressure value by adjusting a calculation formula according to actual parameters.
In one embodiment, the diameter of the sealing plate 40 is equal to that of the two metal bellows 20, so that the sealing plate 40 does not extend out of the metal bellows 20 along the radial direction of the metal bellows 20, two side surfaces of the sealing plate 40 are respectively and completely opposite to the inside of the metal bellows 20, and the sealing plate 40 is only subjected to the pressure of seawater in the metal bellows 20 and is not easily influenced by other external pressure, thereby improving the accuracy and anti-interference capability of the optical fiber pressure sensor. In other embodiments, the diameter of the sealing plate 40 may be larger than that of the two metal bellows 20, and the portion of the sealing plate 40 extending out of the metal bellows 20 along the radial direction of the metal bellows 20 is not affected by other factors in the housing 10, so as to meet the requirement of pressure sensing
In one embodiment, the seal plate 40 is an aluminum sheet with high fatigue resistance and superior sea water resistance suitable for use in a complex subsea environment.
In one embodiment, the two fiber bragg gratings are respectively stuck and fixed in the two metal corrugated pipes 20, and the fiber bragg gratings and the metal corrugated pipes 20 are fixed in a sticking mode, so that the fiber bragg gratings and the metal corrugated pipes 20 can synchronously deform, the process is simple, and the cost is low.
The invention also provides a pressure sensing system, as shown in fig. 3, comprising a light source, a transmission module, a processing module and the optical fiber pressure sensor in any embodiment. The light source is connected with the optical fiber pressure sensor through a signal of the transmission module, the optical fiber pressure sensor is connected with the processing module through a signal of the transmission module, and the processing module processes the obtained signal and outputs a wavelength value.
Specifically, the transmission module comprises two transmission optical fibers and an optical fiber coupler arranged on the two transmission optical fibers, wherein the transmission optical fibers are used for connecting the optical fiber pressure sensor and the light source/processing module by signals, and the two transmission optical fibers are respectively a first transmission optical fiber and a second transmission optical fiber. One end of the first transmission optical fiber is connected with the light source, and the other end of the first transmission optical fiber is connected with an optical fiber of the optical fiber pressure sensor. One end of the second transmission optical fiber is connected with the optical fiber pressure sensor, and the other end of the second transmission optical fiber is connected with the processing module. The light source is a broadband light source, and the optical fiber coupler is a 2×2 optical coupler.
The processing module comprises a photoelectric detection assembly, a wavelength demodulation assembly and a signal acquisition and processing assembly; the optical fiber pressure sensor is connected with the photoelectric detection assembly through a second transmission optical fiber; the photoelectric detector converts the optical signal of the optical fiber pressure sensor into an electric signal and transmits the electric signal to the wavelength demodulation component, the wavelength demodulation component converts the electric signal into a digital signal and transmits the digital signal to the signal acquisition and processing component, and the signal acquisition and processing component further processes the obtained signal and outputs a wavelength value.
The broadband refers to the wavelength range covered by the light emitted by the light source, and the broadband light source in this embodiment is a C-band ASE (amplified spontaneous emission) light source with a wavelength of 1526-1565nm, and the output power is 20dBm, so as to output broadband light to the subsequent components. Subsequent components include 2 x 2 optical couplers, transmission fibers, fiber optic pressure sensors, etc.
C-band ASE (amplified spontaneous emission) beam enters the optical fiber pressure sensor and is subjected to optical fiberBragg grating modulation, the back-reflected light is a light meeting the condition lambda B Selected wavelength light of =2nΛ. Wherein lambda is B The Bragg wavelength is given, n is the effective refractive index of light propagating in the optical fiber, and Λ is the period of the fiber Bragg grating; if the sensing probe receives external pressure, the fiber Bragg grating is stretched or compressed in the range, and the strain on the grating changes n and Λ due to the elasto-optical effect, the Bragg wavelength λ B Change Deltalambda B . And due to the special-structured metal corrugated pipe 20-type dual-fiber Bragg grating push-pull structure, the variation delta lambda of Bragg wavelength is realized under certain pressure B Greatly enhances. In addition, even under the thermo-optical effect, the Bragg wavelength is also affected by temperature, but due to the symmetrical structure of the two fiber Bragg gratings, the temperature effect is counteracted, and the fiber pressure sensor does not need temperature compensation.
When the optical fiber pressure sensor is used, light emitted by a broadband light source is incident to the fiber Bragg grating of the optical fiber pressure sensor through the 2X 2 optical coupler, light reflected by the fiber Bragg grating is sent to the photoelectric detector through the 2X 2 optical coupler, the photoelectric detector converts an optical signal into an electric signal and transmits the electric signal to the wavelength demodulation component, the wavelength demodulation component converts the electric signal into a digital signal and transmits the digital signal to the signal acquisition and processing component, the signal acquisition and processing component further processes and outputs the obtained signal to obtain the central wavelength change, and finally the external pressure can be obtained by adopting a common fiber Bragg grating wavelength demodulation mode.
The pressure sensing system of the present embodiment utilizes the low axial elastic coefficient of the metal bellows 20 and the wavelength-strain sensitivity of the fiber bragg grating to constitute a high-sensitivity pressure sensor; two groups of metal corrugated pipes 20-fiber Bragg gratings are designed and connected through a sealing plate 40 to form a push-pull structure, so that the sensitivity is further doubled; the push-pull structure can radically counteract the temperature influence by utilizing the symmetry of the push-pull structure, and temperature compensation is not needed; the push-pull structure can offset the interference of other factors such as instability of active devices such as a light source in a light path by utilizing the symmetry of the push-pull structure, has strong anti-interference performance, strong stability and high reliability, and is suitable for a submarine complex environment.
The embodiments have been described so as to facilitate a person of ordinary skill in the art in order to understand and apply the present technology, it will be apparent to those skilled in the art that various modifications may be made to these examples and that the general principles described herein may be applied to other embodiments without undue burden. Therefore, the present application is not limited to the above embodiments, and modifications to the following cases should be within the scope of protection of the present application: (1) the technical scheme of the invention is taken as the basis and combined with the new technical scheme implemented by the prior common general knowledge, and the technical effect produced by the new technical scheme is not beyond that of the invention; (2) equivalent replacement of part of the characteristics of the technical scheme of the invention by adopting the known technology produces the technical effect the same as that of the invention; (3) the technical scheme of the invention is taken as a basis for expanding, and the essence of the expanded technical scheme is not beyond the technical scheme of the invention; (4) equivalent transformation made by the content of the specification and the drawings of the invention is directly or indirectly applied to other related technical fields.
Claims (10)
1. The optical fiber pressure sensor is characterized by comprising a shell, a first elastic tube and a second elastic tube, wherein the first elastic tube and the second elastic tube are arranged along the extending and retracting directions of the first elastic tube and the second elastic tube, a sealing plate is arranged between the first elastic tube and the second elastic tube, one ends, close to each other, of the first elastic tube and the second elastic tube are respectively abutted to two sides of the sealing plate and sealed by the sealing plate, and one ends, far away from each other, of the first elastic tube and the second elastic tube are fixedly connected with the shell;
the first fiber Bragg grating is fixed in the first elastic tube along the expansion direction, and the second fiber Bragg grating is fixed in the second elastic tube along the expansion direction.
2. The fiber optic pressure sensor of claim 1, wherein the first and second elastic tubes are each a metal bellows.
3. The fiber optic pressure sensor of claim 2, wherein the first and second elastic tubes are coaxially fixed within the housing.
4. The fiber optic pressure sensor of claim 3, wherein the sealing plate has a diameter equal to a diameter of the first elastic tube/second elastic tube.
5. The fiber optic pressure sensor of claims 2, 3 or 4, wherein the sealing plate is an aluminum sheet.
6. The fiber optic pressure sensor of claim 5, wherein the first fiber bragg grating is adhesively secured within the first elastic tube and the second fiber bragg grating is adhesively secured within the second elastic tube.
7. The optical fiber pressure sensor according to claim 6, wherein the first optical fiber bragg grating and the second optical fiber bragg grating are identical and etched on the same optical fiber, and one end of the optical fiber is fixed to the end of the first elastic tube, and the other end of the optical fiber is fixed to the end of the second elastic tube after passing through the sealing plate.
8. A pressure sensing system, comprising: a light source, a processing module and a fiber optic pressure sensor according to any one of claims 1-7; the optical fiber of the optical fiber pressure sensor is connected with the light source; the processing module is connected with the optical fiber pressure sensor, receives signals of the optical fiber pressure sensor, and outputs wavelength values according to the signals.
9. The pressure sensing system of claim 8, further comprising a transmission module comprising a first transmission fiber and a second transmission fiber for transmitting signals, the first transmission fiber having one end connected to the light source and the other end connected to the optical fiber of the optical fiber pressure sensor; one end of the second transmission optical fiber is connected with the optical fiber pressure sensor, and the other end of the second transmission optical fiber is connected with the processing module.
10. The pressure sensing system of claim 9, wherein the processing module comprises a photodetection assembly, a wavelength demodulation assembly, and a signal acquisition and processing assembly; the optical fiber pressure sensor is connected with the photoelectric detection assembly through the second transmission optical fiber; the photoelectric detector, the wavelength demodulation component and the signal acquisition and processing component are sequentially connected and transmit signals, and the signal acquisition and processing component outputs wavelength values according to the signals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310154333.9A CN116222849A (en) | 2023-02-09 | 2023-02-09 | Optical fiber pressure sensor and sensing system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310154333.9A CN116222849A (en) | 2023-02-09 | 2023-02-09 | Optical fiber pressure sensor and sensing system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116222849A true CN116222849A (en) | 2023-06-06 |
Family
ID=86581995
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310154333.9A Pending CN116222849A (en) | 2023-02-09 | 2023-02-09 | Optical fiber pressure sensor and sensing system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116222849A (en) |
-
2023
- 2023-02-09 CN CN202310154333.9A patent/CN116222849A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5258614A (en) | Optical fiber loop temperature sensor | |
| US5844667A (en) | Fiber optic pressure sensor with passive temperature compensation | |
| Berthold et al. | Design and characterization of a high temperature fiber-optic pressure transducer | |
| US5196694A (en) | Temperature compensated self-referenced fiber optic microbend pressure transducer | |
| WO2011120147A1 (en) | Multi-point pressure sensor and uses thereof | |
| CN111103051A (en) | Optical fiber interference type hydrophone detection system and method | |
| EP1668314A2 (en) | Rugged fabry-perot pressure sensor | |
| BRPI0403240B1 (en) | optical transducer for simultaneous measurement of pressure and temperature in oil wells and method for said measurement | |
| US20140123764A1 (en) | Fiber Bragg Grating Pressure Sensor with Adjustable Sensitivity | |
| CN100460825C (en) | Optical fibre grating sensor based on Bourdon tube as energy changer and method thereof | |
| CA2295011C (en) | Pressure sensor for fluid using an expansion pipe and fiber optical bragg grating | |
| EP3311130A1 (en) | Fiber optic pressure apparatus, methods, and applications | |
| US10663324B2 (en) | Optical fiber sensor | |
| CN116222849A (en) | Optical fiber pressure sensor and sensing system | |
| Pachava et al. | Fiber Bragg grating–based hydraulic pressure sensor with enhanced resolution | |
| CN208313481U (en) | Temperature-compensating remote pressure based on fiber grating senses instrument | |
| CN107677341B (en) | Optical fiber interference water level sensing device and method based on air refractive index | |
| CN210802682U (en) | Optical fiber interference type hydrophone detection system | |
| US8590385B2 (en) | High pressure fiber optic sensor system | |
| CN115597658A (en) | F-P cascade optical fiber sensor and method for measuring temperature and salt of seawater | |
| TWI585373B (en) | Fiber grating sensing system for liquid | |
| CN210741396U (en) | F-P cavity type high-temperature large-strain optical fiber sensor | |
| JP3489496B2 (en) | Optical pressure sensor and pressure measurement method using the same | |
| CN111024211A (en) | High-sensitivity differential optical fiber F-P micro-vibration sensor and demodulation method thereof | |
| CN114993550B (en) | High-reliability differential pressure sensor and sensing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |