CN214309255U - Optical fiber pressure sensor - Google Patents
Optical fiber pressure sensor Download PDFInfo
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- CN214309255U CN214309255U CN202120232921.6U CN202120232921U CN214309255U CN 214309255 U CN214309255 U CN 214309255U CN 202120232921 U CN202120232921 U CN 202120232921U CN 214309255 U CN214309255 U CN 214309255U
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Abstract
The utility model discloses an optic fibre pressure sensor. The utility model adopts the structure that the diameter of the first through hole in the main body is smaller than that of the second through hole, thereby forming a supporting surface, providing support for the first capillary, avoiding stronger shearing force from acting on the adhesive and enhancing the long-time working stability; the first welding point does not need to realize complete sealing, so that welding is carried out by using weaker energy, and the second welding point is manufactured only by ensuring that the end face of the reflection optical fiber is not damaged, so that the welding difficulty is reduced, and the yield is improved; the first welding point is away from the right side of the second through hole and is not covered by the adhesive, and the whole Fabry-Perot cavity section sensing pressure is positioned in the accommodating cavity, so that the influence of the main body and the adhesive on the Fabry-Perot cavity section is avoided; the ultra-low temperature sensitivity can be realized, and the problem that the Fabry-Perot cavity is sensitive to both temperature and pressure is solved; easy to manufacture, high in yield, good in long-time working stability and capable of being used as a good pressure sensor.
Description
Technical Field
The utility model relates to an optical fiber sensing technology field, concretely relates to optic fibre pressure sensor.
Background
Compared with the traditional sensor, the optical fiber sensor is more and more emphasized by people because of the advantages of electromagnetic interference avoidance, electrical immunity, high resolution, high precision, convenience for multiplexing and networking. The Fabry-Perot (Fabry-Perot) pressure sensor has the advantages of small volume, simple structure, high response speed and high reliability, has high sensitivity due to the adoption of an interference technology, is an important optical fiber sensor, can be used for pressure measurement in special environments, and is widely applied to the field of sensing.
The lead-in optical fiber and the reflection optical fiber are put into a collimating capillary glass tube together, and then the optical fiber and the collimating capillary glass tube are fixed together by using epoxy resin to form the optical fiber Fabry-Perot pressure sensor [1 ]. In addition, the optical fiber and the collimating capillary can be welded together by adopting a laser hot melting technology, so that better stability is obtained [2 ]. However, in practical applications, the fiber fabry-perot pressure sensor needs to be designed with a metal package to cope with the complicated and harsh application environment, and the sealing between glass and metal is a difficult problem. Patent CN106323535A shows a package form of optical fiber pressure sensor, which uses two conical surfaces to realize sealing, but the structure will weaken the sealing performance after high and low pressure back and forth impact.
Disclosure of Invention
To the problem that exists among the above prior art, the utility model provides an optic fibre pressure sensor.
The utility model discloses an optic fibre pressure sensor includes: the device comprises a main body, a first through hole, a second through hole, a supporting surface, a first capillary, a second capillary, a third capillary, a lead-in optical fiber, a reflection optical fiber, a first welding point, a second welding point, a plug, an accommodating cavity and a pressure guide hole; the main body is internally provided with a cavity, the left side of the cavity is sequentially provided with a first through hole and a second through hole which are coaxial and mutually communicated, and the diameter of the second through hole is larger than that of the first through hole, so that a supporting surface is formed at the intersection of the second through hole and the first through hole; the leading-in optical fiber is inserted into the second capillary, the right end face of the leading-in optical fiber penetrates out of the right end face of the second capillary, the second capillary is integrally inserted into the first capillary from the left side, and the first capillary is welded with the second capillary and the leading-in optical fiber to form a first welding point; the reflection optical fiber is inserted into the third capillary, the left end face of the reflection optical fiber penetrates out of the left end face of the third capillary, the third capillary is integrally inserted into the first capillary from the right side, and the first capillary, the third capillary and the reflection optical fiber are welded to form a second welding point; a Fabry-Perot cavity is formed between the first welding point and the second welding point; the leading-in optical fiber is coaxial with the reflecting optical fiber, and beam interference is formed between the right end face of the leading-in optical fiber and the left end face of the reflecting optical fiber; the first capillary after welding extends into the cavity and the second through hole in the main body from the right side of the main body, and the leading-in optical fiber extends out from the left side of the main body through the first through hole; the left end face of the first capillary is in contact with a supporting face, and the supporting face provides support for the first capillary; filling adhesive between the first capillary tube and the second through hole so as to fix the first capillary tube in the second through hole; a plug is arranged on the right side of the cavity in the main body and is sealed with the main body to form an accommodating cavity; the first welding point and the second welding point are both positioned in the accommodating cavity, and the first welding point is away from the right side of the second through hole, so that the adhesive does not cover the first welding point; the main part is located and has seted up a plurality of pressure holes of leading on the lateral wall that holds the chamber, and liquid or gaseous get into through leading the pressure hole and hold the intracavity, and then use first capillary on, form pressure to the Fabry-Perot chamber.
The main body and the plug are made of metal, and are made of stainless steel or other metals; the left side of the body can form a sealed connection with other components.
The second capillary and the third capillary have the same inner diameter and outer diameter, the inner diameters of the second capillary and the third capillary are larger than the outer diameters of the leading-in optical fiber and the reflecting optical fiber, the inner diameter of the first capillary is larger than the outer diameters of the second capillary and the third capillary, the outer diameter of the first capillary is smaller than the diameter of the second through hole, and the inner diameter of the first capillary is larger than the diameter of the first through hole. The diameter of the first through hole is larger than the outer diameter of the leading-in optical fiber, so that the leading-in optical fiber can freely pass through the first through hole.
The first capillary, the second capillary and the third capillary are made of the same material as the optical fiber.
And welding the first capillary tube with the second capillary tube and the leading-in optical fiber, welding the first capillary tube with the third capillary tube and the reflecting optical fiber, and adopting arc spot welding or high-energy laser welding.
When the first welding point is welded, the second capillary and the leading-in optical fiber are firmly fixed in the first capillary, and complete sealing is not required.
The second welding point is far away from the left end face of the reflection optical fiber as far as possible, welding is carried out on the tail portion of the first capillary, and the reflection optical fiber, the third capillary and the first capillary are completely fused together.
The right side surface of the leading-in optical fiber is cut or ground to form a flat right end surface of the leading-in optical fiber, the left side surface of the reflecting optical fiber is cut or ground to form a flat left end surface of the reflecting optical fiber, and the right end surface of the leading-in optical fiber and the left end surface of the reflecting optical fiber are plated with high-reflection films or are not plated with the high-reflection films.
The inside of the first capillary tube forms a Fabry-Perot cavity between the first welding point and the second welding point, when the Fabry-Perot cavity receives external pressure, the distance between the right end face of the lead-in optical fiber and the left end face of the reflection optical fiber changes, and the external pressure is obtained by measuring the distance between the two end faces.
The adhesive selects glue to realize the sealing and bonding of the outer wall of the first capillary and the inner wall of the second through hole.
The utility model has the advantages that:
(1) the diameter of the first through hole in the main body is smaller than that of the second through hole to form a supporting surface, and the supporting surface provides support for the first capillary, so that stronger shearing force is prevented from acting on the adhesive, and the long-time working stability of the sensor is enhanced;
(2) the first welding point does not need to realize complete sealing, welding can be carried out by using weaker energy, and only one radial side of the capillary tube and the optical fiber can be welded, so that the welding difficulty is reduced, the possibility that the optical fiber is damaged during welding is reduced, and the yield is improved;
(3) when the second welding point is manufactured, the reflective optical fiber, the third capillary tube and the first capillary tube can be completely fused together by using strong energy, and only the end face of the reflective optical fiber needs to be ensured not to be damaged in the welding process, so that the welding difficulty is reduced, and the yield is improved;
(4) the first welding point is away from the right side of the second through hole by a certain distance, and the adhesive does not cover the first welding point, so that the whole Fabry-Perot cavity section sensing pressure is positioned in the accommodating cavity, and the influence of the main body and the adhesive on the Fabry-Perot cavity section is avoided;
(5) the first capillary, the second capillary and the third capillary are made of the same material as the optical fiber and have extremely low responsivity to temperature, so that the sensor can realize extremely low temperature sensitivity and solve the problem that the Fabry-Perot cavity is sensitive to both temperature and pressure;
(6) easy to manufacture, high in yield, good in long-time working stability and capable of being used as a good pressure sensor.
Drawings
Fig. 1 is a cross-sectional view of an embodiment of the fiber optic pressure sensor of the present invention.
Detailed Description
The invention will be further elucidated by means of specific embodiments in the following with reference to the drawings.
As shown in fig. 1, the optical fiber pressure sensor of the present embodiment includes: the optical fiber splicing device comprises a main body 10, a first through hole 101, a second through hole 102, a supporting surface 103, a first capillary 30, a second capillary 40, a third capillary 41, a leading-in optical fiber 20, a reflecting optical fiber 21, a first fusion point 50, a second fusion point 51, a plug 11, an accommodating cavity 105 and a pressure guide hole 104; the main body 10 is a cylinder, a cavity is arranged in the main body 10, a first through hole 101 and a second through hole 102 which are coaxial and mutually communicated are sequentially formed in the left side of the cavity, and the diameter of the second through hole 102 is larger than that of the first through hole 101, so that a supporting surface 103 is formed at the intersection of the second through hole 102 and the first through hole 101; the leading-in optical fiber 20 is inserted into the second capillary 40, the right end face of the leading-in optical fiber penetrates out of the right end face of the second capillary 40, the second capillary 40 is integrally inserted into the first capillary 30 from the left side, and the first capillary 30 is welded with the second capillary 40 and the leading-in optical fiber 20 to form a first welding point 50; the reflection fiber 21 is inserted into the third capillary 41, the left end face 211 of the reflection fiber passes through the left end face of the third capillary 41, the third capillary 41 is integrally inserted into the first capillary 30 from the right side, and the first capillary 30 is welded with the third capillary 41 and the reflection fiber 21 to form a second welding point 51; the first welding point 50 and the second welding point 51 form a Fabry-Perot cavity 22; the leading-in optical fiber 20 is coaxial with the reflecting optical fiber 21, and beam interference is formed between the right end surface 201 of the leading-in optical fiber and the left end surface 211 of the reflecting optical fiber; the first capillary 30 after fusion splicing extends from the right side of the main body 10 from right to left into the cavity and the second through hole 102 in the main body 10, and the lead-in optical fiber 20 extends from the left side of the main body 10 through the first through hole 101; the left end face of the first capillary 30 is in contact with a support face 103, and the support face 103 provides support for the first capillary 30; the adhesive 60 is filled between the first capillary 30 and the second through hole 102, and the first capillary 30 is fixed in the second through hole 102; a plug 11 is arranged on the right side of the cavity in the main body 10 and is sealed with the main body 10 to form an accommodating cavity 105; the first welding point 50 and the second welding point 51 are both located in the accommodation chamber 105, and the first welding point 50 is located at a distance from the right side of the second through-hole 102 such that the adhesive does not cover the first welding point 50; the main body 10 is provided with a plurality of pressure guide holes 104 on the side wall of the accommodating cavity 105, and liquid or gas enters the accommodating cavity 105 through the pressure guide holes 104 and then acts on the first capillary 30 to form pressure on the Fabry-Perot cavity.
In the present embodiment, the material of the main body 10 and the plug 11 is stainless steel; the first capillary 30, the second capillary 40 and the third capillary 41 are made of the same material as the optical fiber and are made of quartz; welding the first capillary 30 with the second capillary 40 and the introduction fiber 20, and welding the first capillary 30 with the third capillary 41 and the reflection fiber 21, and performing arc spot welding; when the first fusion point 50 is fused, the second capillary 40 and the lead-in optical fiber 20 are firmly fixed in the first capillary 30, and complete sealing is not required; the second fusion point 51 is located as far as possible from the end face of the reflection fiber, and fusion-spliced to the tail of the first capillary 30 to completely fuse together the reflection fiber 21, the third capillary 41, and the first capillary 30; the right side surface of the leading-in optical fiber 20 is cut to form a flat right end surface of the leading-in optical fiber, the left side surface of the reflecting optical fiber 21 is cut to form a flat left end surface of the reflecting optical fiber, and the right end surface of the leading-in optical fiber and the left end surface of the reflecting optical fiber are plated with high-reflection films; the adhesive is selected from thermosetting glue.
In this embodiment, the introduction fiber 20 and the reflection fiber 21 are common single-mode fibers, and have a diameter of 0.125mm, the inner diameters of the second capillary 40 and the third capillary 41 are 0.13mm, and the outer diameter is 0.6mm, the inner diameter of the first capillary 30 is larger than the inner diameters of the second capillary 40 and the third capillary 41 by 0.05 to 0.2mm, the inner diameter of the first capillary 30 is 0.61mm, and the outer diameter is 2mm, and the outer diameter of the second capillary 40 is smaller than the diameter of the second through hole 102 by 1 to 2mm, so that the first capillary 30 can be smoothly inserted into the second through hole 102. The diameter of the first through hole 101 is 0.05-0.2 mm larger than the outer diameter of the lead-in optical fiber 20, so that the lead-in optical fiber 20 can freely pass through the first through hole 101; the diameter of the second through hole 102 is 5-15 times of that of the first through hole 101, the diameter of the first through hole 101 is 0.2mm, and the diameter of the second through hole 102 is 2.1 mm; the outer diameter of the main body 10 is 20mm, and the diameter of the cavity inside the main body 10 is 10 mm.
The inside of the first capillary 30 forms a Fabry-Perot cavity between the first fusion point 50 and the second fusion point 51, and when the Fabry-Perot cavity receives external pressure, the distance between the right end face of the lead-in optical fiber and the left end face of the reflection optical fiber will change, and the external pressure is obtained by measuring the distance between the two end faces.
Finally, it is noted that the disclosed embodiments are intended to aid in further understanding of the invention, but will be understood by those skilled in the art that: various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the embodiments disclosed, and the scope of the present invention is defined by the appended claims.
Reference material:
[1]Murphy K.A.,Gunther M.F.,Vengsarkar A.M.,et al.Quadrature phase-shifted extrinsic Fabry-Perot optical fiber sensors.Optics Letters,1991,24(6):273～275.
[2]A.Wang,H.Xiao,R.G.May,et al.Optical Fiber Sensors for Harsh Environments.In:International Conference on Sensors and Control Techniques.2000.
Claims (6)
1. a fiber optic pressure sensor, comprising: the device comprises a main body, a first through hole, a second through hole, a supporting surface, a first capillary, a second capillary, a third capillary, a lead-in optical fiber, a reflection optical fiber, a first welding point, a second welding point, a plug, an accommodating cavity and a pressure guide hole; the main body is internally provided with a cavity, the left side of the cavity is sequentially provided with a first through hole and a second through hole which are coaxial and mutually communicated, and the diameter of the second through hole is larger than that of the first through hole, so that a supporting surface is formed at the intersection of the second through hole and the first through hole; the leading-in optical fiber is inserted into the second capillary, the right end face of the leading-in optical fiber penetrates out of the right end face of the second capillary, the second capillary is integrally inserted into the first capillary from the left side, and the first capillary is welded with the second capillary and the leading-in optical fiber to form a first welding point; the reflection optical fiber is inserted into the third capillary, the left end face of the reflection optical fiber penetrates out of the left end face of the third capillary, the third capillary is integrally inserted into the first capillary from the right side, and the first capillary, the third capillary and the reflection optical fiber are welded to form a second welding point; a Fabry-Perot cavity is formed between the first welding point and the second welding point; the leading-in optical fiber is coaxial with the reflecting optical fiber, and beam interference is formed between the right end face of the leading-in optical fiber and the left end face of the reflecting optical fiber; the first capillary after welding extends into the cavity and the second through hole in the main body from the right side of the main body, and the leading-in optical fiber extends out from the left side of the main body through the first through hole; the left end face of the first capillary is in contact with a supporting face, and the supporting face provides support for the first capillary; filling adhesive between the first capillary tube and the second through hole so as to fix the first capillary tube in the second through hole; a plug is arranged on the right side of the cavity in the main body and is sealed with the main body to form an accommodating cavity; the first welding point and the second welding point are both positioned in the accommodating cavity, and the first welding point is away from the right side of the second through hole, so that the adhesive does not cover the first welding point; the main part is located and has seted up a plurality of pressure holes of leading on the lateral wall that holds the chamber, and liquid or gaseous get into through leading the pressure hole and hold the intracavity, and then use first capillary on, form pressure to the Fabry-Perot chamber.
2. The fiber optic pressure sensor of claim 1, wherein the body and the plug are made of metal.
3. The optical fiber pressure sensor according to claim 1, wherein the second capillary and the third capillary have the same inner diameter and outer diameter, the inner diameter of the second capillary and the third capillary is larger than the outer diameter of the introduction optical fiber and the reflection optical fiber, the inner diameter of the first capillary is larger than the outer diameter of the second capillary and the third capillary, and the outer diameter of the first capillary is smaller than the diameter of the second through hole.
4. The optical fiber pressure sensor according to claim 1, wherein the first capillary, the second capillary, and the third capillary are made of the same material as the lead-in optical fiber and the reflection optical fiber.
5. The optical fiber pressure sensor according to claim 1, wherein the right side surface of the introduction optical fiber is cut or ground to form a flat right end surface of the introduction optical fiber, and the left side surface of the reflection optical fiber is cut or ground to form a flat left end surface of the reflection optical fiber.
6. The fiber optic pressure sensor of claim 1, wherein the adhesive is selected from glue.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115790923A (en) * | 2022-10-25 | 2023-03-14 | 西北大学 | Fabry-Perot interference type all-fiber pressure sensor based on cantilever structure sensitization |
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- 2021-01-27 CN CN202120232921.6U patent/CN214309255U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115790923A (en) * | 2022-10-25 | 2023-03-14 | 西北大学 | Fabry-Perot interference type all-fiber pressure sensor based on cantilever structure sensitization |
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