阅读说明：本技术 一种推挽式光纤水听器 (Push-pull type optical fiber hydrophone ) 是由 娄威龙 孙华明 王俊 薛超 于 2021-01-08 设计创作，主要内容包括：本发明涉及光纤传感领域,提供了一种推挽式光纤水听器,其特征在于：所述光纤水听器包括弹性体、金属件、舱体、前端盖、后端盖、挡盖；所述弹性体、所述金属件、所述舱体主体部分为一个中空的回转体,所述弹性体套于所述金属件外,所述弹性体与所述金属件共同放置于所述舱体内,所述前端盖与所述后端盖设置于所述舱体前后两端,所述前端盖为一个设有圆形通孔的扁平体,所述金属体与所述挡盖通过所述圆形通孔装配连接,以上所有部件过盈配合且结合处均进行密封胶灌封；光路放置于所述舱体内；本发明通过金属件与弹性体端部内孔的尺寸配合以及密封胶灌封密封,可以对弹性体进行可靠密封。(The invention relates to the field of optical fiber sensing, and provides a push-pull optical fiber hydrophone which is characterized in that: the optical fiber hydrophone comprises an elastic body, a metal piece, a cabin body, a front end cover, a rear end cover and a baffle cover; the elastic body, the metal piece and the cabin body main part are hollow revolving bodies, the elastic body is sleeved outside the metal piece, the elastic body and the metal piece are jointly placed in the cabin body, the front end cover and the rear end cover are arranged at the front end and the rear end of the cabin body, the front end cover is a flat body provided with a circular through hole, the metal body and the baffle cover are assembled and connected through the circular through hole, and all the components are in interference fit and the joints are filled with sealant; the light path is placed in the cabin body; the invention can reliably seal the elastic body by matching the sizes of the metal piece and the inner hole of the end part of the elastic body and filling and sealing the elastic body with the sealant.)

1. A push-pull fiber optic hydrophone, comprising: the optical fiber hydrophone comprises an elastic body (3), a metal piece (4), a cabin body (5), a front end cover (6), a rear end cover (7) and a baffle cover (8); the elastic body (3), the metal piece (4) and the cabin body (5) are mainly hollow revolved bodies, the elastic body (3) is sleeved outside the metal piece (4), the elastic body (3) and the metal piece (4) are jointly placed in the cabin body (5), the front end cover (6) and the rear end cover (7) are arranged at the front end and the rear end of the cabin body (5), the front end cover (6) is a flat body provided with a circular through hole (62), the metal body (4) and the baffle cover (8) are assembled and connected through the circular through hole (62), and all the components are in interference fit and the joints are sealed and filled with glue; the light path is placed in the cabin (5).

2. The push-pull fiber optic hydrophone of claim 1, wherein: the optical path is composed of an optical fiber coupler, two sensitive coils and two reflectors, wherein two optical fibers at one end of the optical fiber coupler are respectively connected with the two sensitive coils, and the two sensitive coils are respectively connected with the two reflectors.

3. The push-pull fiber optic hydrophone of claim 1, wherein: the sealant adopts a bi-component epoxy structural adhesive.

4. A push-pull optical fiber hydrophone according to claim 3, wherein: the elastomer (3) is made of polysulfone or polycarbonate.

5. A push-pull optical fiber hydrophone according to claim 3, wherein: the metal body (4), the cabin body (5), the front end cover (6) and the rear end cover (7) are made of magnesium-aluminum alloy.

Technical Field

The invention relates to the field of optical fiber sensing, in particular to a push-pull optical fiber hydrophone.

Background

The optical fiber sensing technology is a new technology formed along with the development of optical fiber and optical fiber communication technology. The optical fiber hydrophone has sensing sensitivity many times higher than that of the traditional piezoelectric hydrophone, can normally work in many special environments such as high voltage, large noise, high temperature, strong corrosivity and the like, and can be matched with optical fiber remote sensing and remote measuring technologies to form an optical fiber remote sensing system and an optical fiber remote measuring system, so that the optical fiber sensing technology can be widely applied to numerous fields such as aerospace, nuclear industry, bridge tunnels, buildings, oil exploitation, power transmission, medical treatment, scientific research and the like.

The stress action of underwater acoustic waves on the optical fiber changes the refractive index or the length of the fiber core of the optical fiber, so that the optical path of light beams propagating in the optical fiber is changed, and the phase is changed. Phase changes can be detected by interferometric techniques and information about the underwater sound obtained. The phase interference of light is used as a detection means, the detection sensitivity is extremely high, and the response frequency band is also wide; it uses optical fiber as information sensing and transmission medium; the information carried by the light is not interfered by electromagnetic wave, and the danger of leakage does not occur.

Research on fiber optic hydrophones has made great progress, but there is a gap in distance engineering. The performance of the sensitive probe of the optical fiber hydrophone is related to the reliability and stability of the optical fiber hydrophone array, and the engineering application and popularization of the optical fiber hydrophone technology. In the prior art, an optical fiber hydrophone is structurally composed of a device bin and a sensitive component for the optical fiber hydrophone, wherein the sensitive component for the optical fiber hydrophone comprises an elastic body and an outer protective shell;

the optical fiber hydrophone with the structure has the advantages of large overall structure, poor engineering adaptability and limitation to the cable diameter and the bending radius of the towing array, meanwhile, the sealing effect of the sealant can be quickly failed under the seawater environment with a certain depth, the seawater is filled into the air cavity, the complete failure of the optical fiber hydrophone probe can be caused, and the optical fiber hydrophone which is suitable for the severe environment is needed.

Disclosure of Invention

The invention provides a push-pull optical fiber hydrophone, which aims to solve the problems that the optical fiber hydrophone in the prior art is unreliable and easy to leak water under the long-term submarine working environment and the like, and meet the more and more urgent requirements on small size and strong engineering adaptability of sensitive components along with the development of the optical fiber hydrophone, and has the following specific technical scheme:

a push-pull fiber optic hydrophone, comprising: the optical fiber hydrophone comprises an elastic body 3), a metal piece 4, a cabin body 5, a front end cover 6, a rear end cover 7 and a baffle cover 8; the main body parts of the elastic body 3, the metal piece 4 and the cabin body 5 are hollow revolving bodies, the elastic body 3 is sleeved outside the metal piece 4, the elastic body 3 and the metal piece 4 are jointly placed in the cabin body 5, the front end cover 6 and the rear end cover 7 are arranged at the front end and the rear end of the cabin body 5, the front end cover 6 is a flat body provided with a circular through hole 62, the metal body 4 and the baffle cover 8 are assembled and connected through the circular through hole 62, and all the components are in interference fit and sealed glue at the joints; the light path is arranged in the cabin body 5;

furthermore, the optical path is composed of an optical fiber coupler, two sensing coils and two reflectors, two optical fibers at one end of the optical fiber coupler are respectively connected with the two sensing coils, and the two sensing coils are respectively connected with the two reflectors.

Furthermore, the sealant adopts a two-component epoxy structural adhesive.

Furthermore, the elastomer 3 is made of polysulfone or polycarbonate.

Furthermore, the metal body 4, the cabin body 5, the front end cover 6 and the rear end cover 7 are made of magnesium-aluminum alloy.

The invention has the following beneficial effects:

1. the sensitive part of the invention not only has a thin-wall hollow elastomer made of high molecular material, but also has a thin-wall hollow metal piece made of light-weight and high-strength metal material, the sensitive part is sealed by sealing glue, the elastomer can be reliably sealed by the size matching of the metal piece and the inner hole at the end part of the elastomer and the sealing glue sealing, the sealing glue adopts the two kinds of glue bodies which have good sound penetrability, good seawater corrosion resistance and strong adhesive force with the metal, and the two kinds of glue bodies are mixed according to a certain proportion, so that the long-term good sealing performance can be kept in seawater with a certain depth.

2. The push-pull optical path placing and sealing assembly abandons the original mechanical sealing mode, adopts the sealant for sealing, and can reliably seal the cabin body by the size matching of the front end cover, the rear end cover and the inner hole at the end part of the cabin body and the sealing of the sealant. The inner hole of the blocking cover is tightly matched with the end part of the metal piece and is sealed by sealant, and after the blocking cover and the metal piece form a sealing structure, the cabin body is filled with delayed solidification colloid, so that the rigidity of the sealing part can be greatly improved.

3. The push-pull interference light path of the invention consists of an optical fiber coupler, two sensitive coils and two reflectors. Compared with the traditional light path, the double coils of the push-pull light path can improve the sound pressure sensitivity reading and simultaneously can mutually offset the acceleration sensitivity, thereby improving the acoustic performance of the optical fiber hydrophone.

The push-pull optical fiber hydrophone improves the acoustic performance of the optical fiber hydrophone, solves the problems that the optical fiber hydrophone cannot be used under a certain water pressure working environment and is easy to leak water and the like, and meets the requirements of a dragging array on small size, stability, reliability and the like of the optical fiber hydrophone.

Drawings

FIG. 1 is a schematic diagram of a push-pull optical path according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of the elastomer profile structure according to a preferred embodiment of the present invention;

FIG. 3 is a schematic diagram of a metal part configuration according to a preferred embodiment of the present invention;

FIG. 4 is a schematic view of the cabin according to a preferred embodiment of the present invention;

FIG. 5 is a schematic view of the front end cover configuration of a preferred embodiment of the present invention;

FIG. 6 is a schematic view of the rear end cap configuration according to a preferred embodiment of the present invention;

FIG. 7 is a schematic view of the structure of the cover according to a preferred embodiment of the present invention;

FIG. 8 is a partial structural view of a sensitive component assembly according to a preferred embodiment of the present invention;

fig. 9 is an external view of an assembly according to a preferred embodiment of the present invention.

Description of reference numerals:

3. an elastomer; 31. 32: a step; 33. a straight groove; 34. an inner bore surface; 35. a first end face; 36. an outer circular surface;

4. a metal member; 41. an end face; 410. 411, 412, 413, 414, 415: sealing the step surface; 416. an inner bore surface; 42. 43, 44, 45, 46: a step; 47. a straight groove; 48. a through hole; 49. a front end outer wall;

5. a cabin body; 51. a circular through hole; 52. a waist-shaped through hole; 53. a dumbbell-shaped groove; 54. a semicircular groove; 55. a first end face; 56. the inner hole surface of the waist-shaped hole; 57. the inner hole surface of the circular through hole; 58. a second end face;

6. a front end cover; 61. waist-shaped steps, 62 and circular through holes; 63. a tapered hole; 64. a front end cap first step surface; 65. a front end face second step face; 66. a waist-shaped step outer wall; 67. the inner hole surface of the circular through hole;

7. a rear end cap; 71. a waist-shaped step; 72. a semicircular step; 73. a rear end cap first step surface; 74. a rear end cap second step surface; 75. a waist-shaped step outer wall; 76. the outer wall of the semicircular step;

8. a blocking cover; 81. the outer circular surface of the baffle cover; 82. the inner hole surface of the blocking cover.

Detailed Description

The invention is further illustrated by the figures and the specific examples.

The best embodiment is as follows:

the principle of the product is as follows: the underwater acoustic signal acts on the elastic body through the acoustic sensing channel to cause micro-strain of the elastic body, the single-mode optical fiber (sensing optical fiber) wound on the elastic body follows the strain, the strain of the optical fiber immediately changes (modulates) the phase of light waves transmitted in the optical fiber, and the phase change of light in the sensing optical fiber is reflected in the output light intensity of the optical fiber Michelson interferometer where the sensing optical fiber is located, the light path of the product is shown in figure 1, two optical fibers at one end of the optical fiber coupler are respectively connected with two coils, and the two coils are respectively connected with two reflectors.

The basic relational expression is as follows:

I＝A+B cos(Φ_s+Φ₀)

in the formula, I is output light intensity of the optical fiber Michelson interferometer, a is a direct current component, B is alternating current component amplitude caused by laser interference, Φ s is an optical phase shift which can be modulated by sound pressure or other physical quantities, Φ s is 4 π nL/λ, n is a fiber core refractive index, L is a sensitive fiber length, λ is a laser operating wavelength, and Φ 0 is an initial phase difference between a signal arm and a reference arm of the interferometer. The working process of the product is to demodulate the change of phi s from the change of the output light intensity I of the optical fiber Michelson interferometer, thereby determining the size of the sound pressure P causing the change of phi s.

The present embodiment includes the following components: elastomer 3, metal piece 4, cabin body 5, front end cover 6, rear end cover 7, fender lid 8, light path.

As shown in fig. 2, the main body part of the elastic body 3 is a thin-walled hollow rotator made of polysulfone, polycarbonate, or the like; the outer circumference of the main body part of the elastic body 3 is provided with a step 31 at the front part and a step 32 at the rear part, and the step 31 is provided with a straight groove 33 for the optical fiber to penetrate through on the winding side of the optical fiber; the optical fiber outlet of the straight groove 33 is subjected to blunt smooth transition treatment;

as shown in fig. 3, the main body part of the metal part 4 is a thin-walled hollow rotator made of magnesium-aluminum alloy; the outer circumference of the main body part of the metal piece 4 is provided with an end face 41, a step 42 and a step 43 at the front part, and is provided with a step 44, a step 45 and a step 46 at the rear part, the cylindrical surface 41 is in interference fit with the inner hole surface of the baffle cover 8, the cylindrical surfaces of the step 42, the step 43 and the step 44 are in interference fit with the inner hole surface of the elastic body 3, and the cylindrical surfaces of the step 44 and the step 45 are provided with straight grooves 47 for the optical fibers to penetrate through; the optical fiber outlet of the straight groove 47 is subjected to blunt smooth transition treatment, and the inner side of the step 46 is provided with a through hole 48 through which the common optical fiber penetrates;

the push-pull optical fiber hydrophone mainly comprises an elastic body 3 for winding a fixed-length optical fiber on the outer circumference, a metal piece 4 for winding the fixed-length optical fiber on the outer circumference and a sealing component for placing a push-pull optical path;

the sealing assembly for placing the push-pull light path comprises a cabin body 5, a front end cover 6, a rear end cover 7 and a blocking cover 8;

as shown in fig. 4, the cabin 5 is an irregular thin-wall body made of magnesium aluminum alloy, and the cabin 5 includes a circular through hole 51, a waist-shaped through hole 52, and a dumbbell-shaped groove 53; interference fit is formed between the inner hole surface of the circular through hole 51 and the cylindrical surface of the step 45 of the metal piece 4, interference fit is formed between the inner hole surfaces of the circular through hole 51 and the kidney-shaped through hole 52 and the cylindrical surfaces of the kidney-shaped step 61 of the front end cover 6, the kidney-shaped step 71 of the rear end cover 7 and the semicircular step 72, and the dumbbell-shaped groove 53 is used for placing a push-pull light path; a semi-circular groove 54 for the optical fiber to pass through is arranged between the circular through hole 51 and the waist-shaped through hole 52 at one end of the cabin body 5.

As shown in fig. 5, the front end cover 6 is an irregular flat body made of magnesium-aluminum alloy, and the front end cover 6 includes a waist-shaped step 61, a circular through hole 62 and a tapered hole 63; an interference fit is formed between the cylindrical surface of the waist-shaped step 61 and the inner hole surface of the waist-shaped through hole 52 of the cabin body 5, the circular through hole 62 is used for penetrating through the metal piece 4, and the tapered hole 63 is used for fixing a guide cable;

as shown in fig. 6, the rear end cap 7 is an irregular flat body made of magnesium-aluminum alloy, and the rear end cap 7 includes a waist-shaped step 71 and a semicircular step 72; the cylindrical surfaces of the waist-shaped step 71 and the semicircular step 72 are in interference fit with the inner hole surfaces of the circular through hole 51 and the waist-shaped through hole 52 of the cabin 5 respectively;

as shown in fig. 7, the blocking cover 8 is sleeved on the outer wall of the front end of the metal part 4 for improving the rigidity of the formed sealing structure, and the blocking cover 8 is a revolving body made of stainless steel material and is in interference fit with the outer wall of the end of the metal part 4.

The method of making this embodiment is as follows:

as shown in fig. 2, the elastic body 3 is a thin-walled hollow revolving body made of polysulfone, polycarbonate, etc., and is formed into a blank by injection molding at high temperature by using a mold, and then the outer circular surface is polished by using a molybdenum sand skin with the specification of 1200, and then the turning of the inner hole at the end part is completed; the front part and the rear part of the revolving body are respectively provided with two steps 31 and 32, the steps 31 are provided with a straight groove 33 for the optical fiber wound on the outer circular surface of the elastomer 3 to penetrate through; the optical fiber outlet of the straight groove 33 needs to be subjected to blunting smooth transition treatment, and no step exists at the joint of the straight groove 33 and the outer circular surface of the elastomer 3; the elastic body 3 is provided with an inner hole surface 34, and sealing step surfaces 412 which are matched with the metal piece 4 are arranged in the inner holes at the two ends of the elastic body 3; the size of the sealing step surface 412 is designed according to the sealing requirement; the radial dimension of the inner hole surface 34 of the elastic body 3 is designed according to the requirements of the sensor on the compression strength, the sound pressure sensitivity, the frequency response and the like of sensitive parts; the surface of the outer circular surface 36 needs to be wound with optical fibers with a certain length, and has specific requirements on surface finish.

As shown in fig. 3, the metal part 4 is a thin-walled hollow revolving body made of a light-weight and high-strength metal material, the revolving body is respectively provided with five sealing step surfaces 410, 411, 412, 414 and 415 at the front part and the rear part, and the steps 44 and 45 are provided with straight grooves 47 on cylindrical surfaces for optical fibers to penetrate through; the optical fiber outlet of the straight groove 47 is subjected to blunt smooth transition treatment, and no step exists at the joint of the straight groove 47 and the outer circular surface of the elastomer; through holes 48 through which the common optical fibers penetrate are formed in the sealing step surfaces 414 and 415, inner hole surfaces are formed on the metal piece, and the sealing step surfaces 410, 411 and 44 at the two ends of the metal piece are in interference fit with the inner holes of the elastic body 3; the size of the seal step face 415 is designed according to the sealing requirements; the radial dimension of the inner hole surface 416 of the metal piece is designed according to the requirements of the sensor on the compression strength, the frequency response and the like of a sensitive part; the surface of the sealing step surface 413 needs to be wound with a certain length of optical fiber, and has specific requirements on surface finish.

The first end face 35 of the elastic body 3 is pushed into the second step face 415 of the metal piece and is installed in place, sealing glue is filled and sealed, the sealing glue is a bi-component epoxy structural adhesive, is a strong-polarity high polymer material, has low affinity with non-polar mineral oil, is hardly corroded in fuel oil (such as kerosene and gasoline) and mechanical oil (such as hydraulic oil, engine oil and lubricating oil), and has good water resistance and sound permeability, the product selected in the embodiment is sealing glue of Hangao brand, and the model is LETAI glue and EA E-30 CL.

Pushing the metal part 4 into the circular through hole 51 of the cabin body and installing the metal part in place, installing the second step surface 65 of the front end cover on the second end surface 58 of the cabin body and installing the same in place, installing the second step surface 74 of the rear end cover on the first end surface 55 of the cabin body and installing the same in place, sleeving the inner hole surface 82 of the baffle cover on the outer wall 49 of the front end of the metal part and installing the same in place, coating sealant on all contact surfaces for sealing, forming interference fit between the inner hole surface 57 of the circular through hole of the cabin body and the sealing step surface 412 of the metal part, forming interference fit between the inner hole surface 57 of the circular through hole of the cabin body and the outer wall 76 of the semicircular step of the rear end cover; an interference fit is formed between the outer wall 66 of the waist-shaped step of the front end cover and the inner hole surface 56 of the waist-shaped through hole of the cabin body, and an interference fit is formed between the inner hole surface 67 of the circular through hole of the front end cover and the outer circle surface 81 of the baffle cover; an interference fit is formed between the outer wall 75 of the waist-shaped step of the rear end cover and the inner hole surface 56 of the waist-shaped through hole of the cabin body, and an interference fit is formed between the outer wall 76 of the semicircular step of the rear end cover and the inner hole surface 57 of the circular through hole of the cabin body; the inner hole surface 82 of the baffle cover 8 is in interference fit with the outer wall 49 at the front end of the metal piece 4; the outer circular surface 81 and the inner hole surface 67 of the circular through hole of the front end cover are in interference fit. Then, push-pull light path manufacturing is carried out, the light path is placed in the cabin body, and sealant filling and sealing are carried out in the cabin body.

And (5) finishing the installation operation according to the steps, namely finishing the manufacture of the push-pull optical fiber hydrophone.

The embodiment can be assembled by selecting various suitable materials and relevant processing means and processing the materials into corresponding parts according to the engineering drawings of the parts. The size of the finished push-pull optical fiber hydrophone is 20mm in diameter and 62mm in length.