CN201449306U - Fiber bragg grating pressure sensor - Google Patents
Fiber bragg grating pressure sensor Download PDFInfo
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- CN201449306U CN201449306U CN2009200325898U CN200920032589U CN201449306U CN 201449306 U CN201449306 U CN 201449306U CN 2009200325898 U CN2009200325898 U CN 2009200325898U CN 200920032589 U CN200920032589 U CN 200920032589U CN 201449306 U CN201449306 U CN 201449306U
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- fiber
- bragg grating
- tubular shell
- fiber bragg
- polymkeric substance
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Abstract
The utility model relates to a fiber bragg grating pressure sensor, which is characterized in that a fiber bragg grating is packaged in a tubular shell with one end being opened; one end of the fiber bragg grating penetrates out of a small hole at the unopened end surface of the tubular shell and is connected with a fiber optic coupler by single mode fiber; the two sides of the fiber optic coupler are provided with four ports in total; another port of one side connected with the fiber optic coupler is arranged in refractive index matching fluid of optical fiber by the single mode fiber; for the two ports of the other side of the fiber optic coupler, one end is connected with a wideband light source by the single mode fiber, and the other end is connected with a demodulating system by the single mode fiber; and the packaged fiber bragg grating adopts a mode that polymer is filled in the tubular shell. The fiber bragg grating pressure sensor only uses one fiber bragg grating as a pressure sensitive element, simultaneously can avoid the influence of ambient temperature change to precise perception of pressure signals, and also can change spreading quantity of reflective spectrum bandwidth of the fiber bragg grating by changing modulus of elasticity of the polymer, and further change the measuring precision and range of the sensor.
Description
Technical field
The utility model relates to a kind of fiber bragg grating pressure sensor, belongs to sensor technical field, the pressure transducer technology that particularly a kind of sensitive element is a fiber grating.
Background technology
Along with the continuous maturation that the continuous development and the fiber grating of optical fiber sensitization technology writes technology, fiber grating is widely used in field of sensing technologies as a kind of new strain sensing element.Traditional pressure transducer kind is a lot, as the piezoresistive pressure sensor of based semiconductor material piezoresistive effect, based on the capacitance pressure transducer, of presser sensor capacitor, based on piezoelectric pressure indicator of material piezoelectric effect etc.The common feature of these pressure transducers is to be active structure, thereby is subjected to the interference of ambient electromagnetic field easily, and pressure-responsive speed is slow, and hysteresis quality is bigger, and sensitivity is low, and measurement range is narrower, also is difficult to be applied in inflammable, the explosive and corrosion-prone environment.With the sensitive element of fiber grating as pressure transducer, be characterized in the induction and the transmission of transducing signal are all finished in optical fiber, thereby probe is passive structures, signal is not subjected to the influence of ambient electromagnetic field, dependable performance, and can under high temperature, extreme environment such as inflammable, explosive and perishable, use.Yet,, bring the temperature, pressure cross sensitivity because the variation of temperature and pressure all will cause moving of fiber grating centre wavelength.Therefore, how can effectively solve the cross sensitivity problem of temperature and pressure, promptly eliminating Temperature Influence in gaging pressure is the key of this type of sensor practicability.
Sun An, Qiao Xueguang etc. once proposed a kind of fiber bragg grating pressure sensor based on polymer encapsulated (Sun An, Qiao Xueguang, Jia Zhenan, Guo group, Chen Changyong, high pressure resistant optical fiber Bragg raster pressure sensing technology research, the photon journal, 2004,33 (7)), be characterized in, before the packaged fiber grating, adopt the heat-conducting type organic silica gel to apply curing,, prevent from course of exerting pressure, to occur the chirp phenomenon of fiber grating to reduce bonding and the friction between encapsulating material and the tubular shell.But this structure also need be added temperature compensation means in actual pressure is measured, can keep the accuracy of measuring.
Summary of the invention
The technical matters that solves
For fear of the deficiencies in the prior art part, the utility model proposes a kind of fiber bragg grating pressure sensor, utilize coarse tubular shell inwall and polymkeric substance tight bond to increase the chirp value of fiber grating, and then the bandwidth demodulation of employing fiber grating, because temperature change can not influence the variation of bandwidth, can guarantee that therefore sensor avoids Temperature Influence.
Technical scheme
Basic thought of the present utility model is: fiber grating is encapsulated in the polymkeric substance, around the polymkeric substance under the limited situation, its exposed end produces gradient strain at its end face near zone along its central axis because of being subjected to well-distributed pressure, the fiber grating that causes being encapsulated in this gradient strain regions produces axial strain heterogeneous, thereby makes the reflectance spectrum generation chirp phenomenon of fiber grating and the broadening of bandwidth.Meanwhile, the variation of environment temperature can only cause the drift of fiber grating foveal reflex wavelength, and can not bring the broadening of reflection spectrum bandwidth.Therefore, can obtain the size of force value by demodulation reflection spectrum bandwidth information.
Of the present utility model being characterised in that: fiber grating 1 is encapsulated in the tubular shell 3 of an end opening, an end of fiber grating 1 by tubular shell 3 not the aperture at open end center pass and single-mode fiber 9 be connected with fiber coupler 5; Fiber coupler 5 both sides have four ports, and another port connection of a side that is connected with fiber coupler 5 places optical fibre refractivity matching fluid 8 by single-mode fiber 9; Two ports of fiber coupler 5 opposite sides, an end connects wideband light source 6, one ends by single-mode fiber 9 and connects demodulating system 7 by single-mode fiber 9; Packaged fiber grating 1 adopts polymkeric substance 2 fillings in tubular shell 3.
Described tubular shell 3 is: the end at hollow cylinder 4 is to adopt the protection bonnet 11 that is threaded, and the center of protection bonnet 11 is provided with the aperture that passes through for single-mode fiber 9.
The grid region part of fiber grating is encapsulated in the almost gradient strain zone of polymkeric substance 2, and this zone is 5-20mm apart from the scope of polymkeric substance pressure-bearing surface 10.
Beneficial effect
Fiber bragg grating pressure sensor free from temperature influence of the present utility model, only utilize a fiber grating as pressure-sensing device, can avoid simultaneously variation of ambient temperature to the accurate perception influence of pressure signal, but also can change the broadening amount of fiber grating reflection spectrum bandwidth, and then change the measuring accuracy and the range of this sensor by the elastic modulus that changes polymkeric substance.Simultaneously, advantage such as that this sensor has is simple in structure, be easy to realize, measurement range is big on the technology is fit to the sensing measurement of big pressure such as oil well or deep water very much.
Description of drawings
Fig. 1 is fiber grating bandwidth tuning principle schematic under the gradient strain.The cycle variation characteristic of fiber grating before the corresponding respectively encapsulation polymkeric substance of Fig. 1 (a) and Fig. 1 (b) pressurized and behind the pressurized.
Fig. 2 is encapsulation polymkeric substance exposed end its axial strain distribution curve under the well-distributed pressure effect that utilizes the finite element method analog computation to obtain.
Fig. 3 is the fiber bragg grating pressure sensor structural drawing of employing mode 1.
Fig. 4 is the fiber bragg grating pressure sensor structural drawing of employing mode 2.
Wherein: 1, fiber grating; 2, polymkeric substance; 3, tubular shell first; 4, hollow cylinder; 5, fiber coupler; 6, wideband light source; 7. demodulating system; 8, index-matching fluid; 9, single-mode fiber; 10, polymkeric substance pressure-bearing surface; 11, protection bonnet.
Embodiment
Now in conjunction with the embodiments, accompanying drawing is further described the utility model:
Embodiment 1: consult accompanying drawing 3,
Fiber grating is selected Bragg grating 1, Bragg grating 1 is encapsulated in the tubular metal housing 3 of an end opening, an end of fiber grating 1 by tubular shell 3 not the aperture at open end center pass and single-mode fiber 9 is connected with 2 * 2 3dB fiber coupler 5; Fiber coupler 5 both sides have four ports, and another port connection of a side that is connected with fiber coupler 5 places optical fibre refractivity matching fluid 8 by single-mode fiber 9; Two ports of fiber coupler 5 opposite sides, an end connects wideband light source 6, one ends by single-mode fiber 9 and connects demodulating system 7 by single-mode fiber 9; Packaged fiber grating 1 adopts 2 fillings of polymkeric substance acrylate in tubular shell 3.
Installation step is as follows: tubular shell first 3 of (1) processing also makes its inwall keep coarse, the polymkeric substance 2 that is beneficial to encapsulate can with its tight bond; (2) remove the coat of fiber grating 1 part to be packaged, can effectively avoid the be stretched reverse drift of rear center's wavelength of fiber grating 1 like this; (3) fiber grating 1 is placed on tubular shell 3 central axis and to it carry out prestretched, then the polymkeric substance 2 for preparing is filled in the tubular shell first 3; (4) after the polymkeric substance 2 of filling solidifies, this sensor is calibrated measurement. during measurement, the light that wideband light source 6 sends arrives the fiber grating 1 that is encapsulated in the polymkeric substance 2 through fiber coupler 5, arrive demodulating system 7. by fiber coupler 5 behind the reflected signal and on polymkeric substance pressure-bearing surface 10, apply well-distributed pressure simultaneously, the broadened bandwidth amount of measuring optical fiber grating 1 reflectance spectrum, finally the broadening amount by bandwidth obtains applied pressure value size.
Embodiment 2: consult accompanying drawing 4, adopt the fiber bragg grating pressure sensor structural drawing of packaged type 2.Encapsulation step is as follows: (1) processing alloy tubular shell 4 and protection bonnet 11, and both can be connected by sealing thread, the inwall of same tubular shell 4 is worn into uneven surface; (2) remove the coat of Bragg grating 1 packed part; (3) place fiber grating 1 and on tubular shell 4 central axis and to it, carry out prestretched, then the polymer polyurethane 2 for preparing is encapsulated in the tubular shell 4; (4) will protect bonnet 11 to be added on the tubular shell 4, calibrate measurement after the polymkeric substance 2 of encapsulation solidifies.Its measuring method is with shown in Figure 3 identical.
Claims (4)
1. fiber bragg grating pressure sensor free from temperature influence, it is characterized in that: fiber grating (1) is encapsulated in the tubular shell (3) of an end opening, an end of fiber grating (1) by tubular shell (3) not the aperture at open end center pass and single-mode fiber (9) be connected with fiber coupler (5); Fiber coupler (5) both sides have four ports, and another port connection of a side that is connected with fiber coupler (5) places optical fibre refractivity matching fluid (8) by single-mode fiber (9); Two ports of fiber coupler (5) opposite side, an end connects wideband light source (6) by single-mode fiber (9), and an end connects demodulating system (7) by single-mode fiber (9); Packaged fiber grating (1) adopts polymkeric substance (2) filling in tubular shell (3).
2. fiber bragg grating pressure sensor free from temperature influence according to claim 1; it is characterized in that: described tubular shell (3) is: the end at hollow cylinder (4) is to adopt the protection bonnet (11) that is threaded, and the center of protection bonnet (11) is provided with the aperture that passes through for single-mode fiber (9).
3. fiber bragg grating pressure sensor free from temperature influence according to claim 1 and 2, it is characterized in that: the grid region part of fiber grating is encapsulated in the almost gradient strain zone of polymkeric substance (2), and this zone is 5-20mm apart from the scope of polymkeric substance pressure-bearing surface (10).
4. according to claim 1 or 3 described any fiber bragg grating pressure sensors free from temperature influence, it is characterized in that: described polymkeric substance is acrylate or polyurethane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009200325898U CN201449306U (en) | 2009-04-15 | 2009-04-15 | Fiber bragg grating pressure sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009200325898U CN201449306U (en) | 2009-04-15 | 2009-04-15 | Fiber bragg grating pressure sensor |
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| Publication Number | Publication Date |
|---|---|
| CN201449306U true CN201449306U (en) | 2010-05-05 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2009200325898U Expired - Lifetime CN201449306U (en) | 2009-04-15 | 2009-04-15 | Fiber bragg grating pressure sensor |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107462348A (en) * | 2017-09-30 | 2017-12-12 | 南阳理工学院 | For temperature, blast, measuring wind speed multi-parameter optical fiber optical grating sensor |
| CN108801308A (en) * | 2018-08-29 | 2018-11-13 | 闫静 | A kind of fiber grating Multifunction Sensor |
| CN109186821A (en) * | 2018-07-25 | 2019-01-11 | 孝感锐创机械科技有限公司 | A kind of contactless micro-vibration and device for pressure measurement |
| CN111868491A (en) * | 2017-03-21 | 2020-10-30 | 南洋理工大学 | Light sensor, sensor device and method for sensing |
-
2009
- 2009-04-15 CN CN2009200325898U patent/CN201449306U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111868491A (en) * | 2017-03-21 | 2020-10-30 | 南洋理工大学 | Light sensor, sensor device and method for sensing |
| CN111868491B (en) * | 2017-03-21 | 2022-08-26 | 南洋理工大学 | Light sensor, sensor device and method for sensing |
| CN107462348A (en) * | 2017-09-30 | 2017-12-12 | 南阳理工学院 | For temperature, blast, measuring wind speed multi-parameter optical fiber optical grating sensor |
| CN109186821A (en) * | 2018-07-25 | 2019-01-11 | 孝感锐创机械科技有限公司 | A kind of contactless micro-vibration and device for pressure measurement |
| CN108801308A (en) * | 2018-08-29 | 2018-11-13 | 闫静 | A kind of fiber grating Multifunction Sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20100505 Effective date of abandoning: 20090415 |