A high-pressure-resistant FP cavity hydrophone probe device

Abstract

The present invention provides a kind of F-P cavity optical fiber hydrophone probe device that belongs to the field of optical fiber sensing technology, specifically relates to a high-pressure resistant F-P cavity. The present invention has a water-proof and pressure-resistant sound-transparent cap structure on the outside, which can provide an independent and clean working environment for the internal vibrating diaphragm. In addition, the present invention has a constant pressure connecting hole on the side of the ceramic F-P cavity, and a hose is wrapped around the outside of the ceramic F-P cavity starting from the connecting hole. Relying on this structure, when the external water pressure increases, the pressure can be transmitted to the inside of the F-P cavity through the hose, so that the pressure inside and outside the diaphragm is balanced. In this way, under high-pressure environment, when the external sound pressure signal acts on the diaphragm, the diaphragm can vibrate normally, thereby changing the resonant wavelength of the reflected light, and the underwater acoustic signal can be detected. The present invention effectively combines the advantages of the water-proof and pressure-resistant structure and the connecting hole structure, increases the working ability of the probe in the harsh environment of the deep sea ocean, and has the advantages of simple structure, resistance to ultra-high pressure, high sensitivity and low manufacturing cost.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a high-pressure-resistant FP cavity hydrophone probe device. Background Art

[0002] Fiber-optic hydrophones are widely used in underwater acoustic detection technology due to their high sensitivity, wide response bandwidth, resistance to electromagnetic interference, and ease of large-scale array formation. They are particularly popular in underwater distribution monitoring and submarine underwater acoustic detection. In actual operation, hydrophone failure often occurs due to factors such as the exposure of the diaphragm that receives underwater sound, resulting in rupture due to pressure imbalance inside and outside the hydrophone under high-pressure conditions. Therefore, ensuring that fiber-optic hydrophones function properly in high-pressure environments, have a long service life, and have low production costs are essential prerequisites for their large-scale application.

[0003] The currently used fiber optic hydrophone probe is designed to withstand high pressure, including methods such as changing the diaphragm material, designing the connecting hole structure, and designing a pressure-resistant shell. Among them, the existing connecting hole structure design includes two methods: resonant cavity machining and drilling, and micro-nano machining of microfluidic channels. The resonant cavity machining drilling process is simple and low-cost, but after drilling, the external seawater liquid will enter the resonant cavity, affecting the light propagation in the resonant cavity and thus greatly affecting the sensitivity of the hydrophone. The micro-nano machining of microfluidic channels can prevent external seawater from entering the resonant cavity, but the micro-nano machining cost is high, and the microfluidic channels have high requirements for the liquid environment. They are not suitable for the actual working seawater environment, making this type of hydrophone unable to be widely popularized and applied. In summary, in view of the limitations of the existing technology, the present invention combines the advantages of the two structures of resonant cavity shell machining and micro-nano machining of microfluidic channels, and integrates the waterproof cover structure to design a new type of low-cost FP cavity hydrophone probe device that can withstand high pressure. Summary of the Invention

[0004] The object of the present invention is to provide a fiber optic hydrophone probe device that can withstand high pressure.

[0005] The purpose of the present invention is achieved through the following technical solutions: including a water-proof cap, a fixed base, a metal diaphragm, a ceramic sleeve, a constant pressure hose, an optical fiber and an optical fiber ferrule. The interior of the ceramic sleeve is cylindrical and hollow, with cylindrical hole openings at the centers of the upper and lower ends, and a circular hole is also opened on the side of the cylinder and passes through the single-side side wall; one end of the constant pressure hose is inserted into the side of the ceramic sleeve through the circular hole, and is spirally wound around the outside of the ceramic sleeve; the metal diaphragm covers the cylindrical hole opening at the upper end of the ceramic sleeve, and the upper end of the optical fiber ferrule is inserted into the cylindrical hole opening at the lower end of the ceramic sleeve; the optical fiber is inserted into the interior of the ceramic sleeve through the optical fiber ferrule, and a resonant cavity is formed by controlling the distance between the end face of the inserted optical fiber and the metal diaphragm. ; The lower end handle of the optical fiber ferrule is inserted into the central hole of the fixed base, and the lower end of the optical fiber and the central hole of the fixed base are bonded and sealed by epoxy resin glue; the interior of the water-blocking cap is hollow, with a circular opening at the lower end, the upper end is closed, and the lower end is inserted into the circular groove of the fixed base, wherein the interior of the water-blocking cap is filled with liquid, and the lower end of the water-blocking cap and the edge of the circular groove of the fixed base are bonded and sealed by epoxy resin; the probe composed of a ceramic sleeve, a constant pressure hose, a metal diaphragm, and an optical fiber ferrule is located in an independent sealed chamber formed by the water-blocking cap and the fixed base.

[0006] The present invention may also include:

[0007] The bottom end of the watertight cap is inserted into the circular groove of the fixed base, forming an independent sealed chamber. The optical fiber extends out of the sealed chamber through the central hole of the fixed base, and all other components are located within the independent sealed chamber. The watertight cap and the fixed base are sealed and filled with liquid to form an independent sealed chamber. One end of the optical fiber is located outside the independent sealed chamber, and the other end is located inside the independent sealed chamber.

[0008] The optical fiber is located at one end of an independent sealed chamber and is inserted into the ceramic sleeve through the optical fiber ferrule. The upper end of the optical fiber ferrule is inserted into the cylindrical hole opening at the lower end of the ceramic sleeve. The lower end of the optical fiber ferrule is inserted into the central hole of the fixed base. There is a cylindrical pipe in the middle of the optical fiber ferrule. The optical fiber is inserted into the ceramic sleeve through the cylindrical pipe and is perpendicular to the metal diaphragm.

[0009] The upper end of the ceramic sleeve is covered with a metal diaphragm, and the lower end is inserted with an optical fiber ferrule. The interior of the ceramic sleeve is hollow, forming an independent chamber, which is only connected to the independent sealed chamber formed by the water-blocking cap and the fixed base through a constant pressure hose.

[0010] A circular hole is opened on the side of the ceramic sleeve, and one end of the constant pressure hose is inserted into the ceramic sleeve through the circular hole. The constant pressure hose body is spirally wound around the ceramic sleeve, and the other end of the constant pressure hose is placed in an independent sealed chamber formed by the water-blocking cap and the fixed base seal.

[0011] One end of the constant pressure hose is located inside the ceramic sleeve, and the other end is located in an independent sealed chamber formed by a water-blocking cap and a fixed base. The liquid in the independent sealed chamber can enter the ceramic sleeve through a pipe or form an air cavity inside the pipe that can change with pressure.

[0012] The optical fiber is a single-mode optical fiber; the ceramic sleeve is made of zirconia ceramic, and the cylindrical hole opening at the upper end of the ceramic sleeve is larger than the cylindrical hole opening at the lower end of the ceramic sleeve, thereby increasing the coverage area of ​​the metal diaphragm; the metal diaphragm is made of gold or aluminum; the optical fiber ferrule is an ordinary standard ferrule; the fixed base is made of stainless steel; the waterproof cap is made of polyurethane rubber and is sealed to the fixed base by epoxy resin glue.

[0013] The beneficial effects of the present invention are:

[0014] The present invention addresses the limitations of existing fiber optic hydrophone probes by providing a high-pressure-resistant FP cavity hydrophone probe device. A metal diaphragm is coated on the top of a ceramic sleeve to reflect light emitted from the fiber end face. The metal diaphragm structure transmits external sound pressure signals to the fiber. The vibrating metal diaphragm changes the distance between its center point and the fiber end face, thereby altering the wavelength of the optical signal resonant peak within the fiber, enabling detection of underwater acoustic signals. The present invention effectively combines the advantages of perforating the resonant cavity shell and micro-nanofabrication microfluidic channel methods. After perforating the resonant shell, the length of the hole is extended through a constant-pressure hose. This ensures the hydrophone's high pressure resistance while minimizing the impact of the connecting hole on sensor sensitivity and reducing processing costs. In this way, the hydrophone probe fabricated by the present invention has the advantages of small size, simple structure, high-pressure resistance, operation in harsh environments, and low manufacturing cost. Compared to conventional FP cavity hydrophones, the present invention offers superior high-pressure resistance, low cost, and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0016] Figure 1 This is a schematic diagram of the overall structure of the hydrophone probe of the present invention.

[0017] Figure 2 This is a schematic cross-sectional view of the overall structure of the hydrophone probe of the present invention.

[0018] Figure 3 yes Figure 2 Isometric diagram of the ceramic sleeve structure

[0019] Figure 4 yes Figure 2 Schematic diagram of the internal probe structure

[0020] In the figure: 1-waterproof cap, 2-fixed base, 3-metal diaphragm, 4-ceramic sleeve, 5-constant pressure hose, 6-optical fiber, 7-optical fiber ferrule. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the scope of protection of the present invention.

[0022] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0023] As used in the embodiments of the present invention and the appended claims, the singular forms "a", "an", "said" and "the" are intended to include the plural forms as well, and "a plurality" generally includes at least two, unless the context clearly indicates otherwise.

[0024] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0025] It should be understood that although the terms first, second, third, etc. may be used to describe the embodiments of the present invention, they should not be limited to these terms.

[0026] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0027] This patent belongs to the field of optical fiber sensing technology and proposes a high-pressure-resistant optical fiber hydrophone probe device. Figure 1 This is a schematic diagram of the overall structure of the present invention. Figure 2 It is a schematic cross-sectional view of the overall structure of the present invention.

[0028] like Figure 2 As shown, the present invention relates to a high-pressure-resistant optical fiber hydrophone probe device, comprising a water-proof cap 1, a fixed base 2, a metal diaphragm 3, a ceramic sleeve 4, a constant pressure hose 5, an optical fiber 6 and an optical fiber ferrule 7.

[0029] like Figure 3 As shown, the interior of the ceramic sleeve is cylindrical and hollow, with cylindrical holes openings at the centers of the upper and lower ends, and a circular hole also opened on the side of the cylinder and passing through one side wall;

[0030] like Figure 4 As shown, one end of the constant pressure hose 5 is inserted into the side of the ceramic sleeve through the circular hole and is spirally wound around the outside of the ceramic sleeve; the metal diaphragm 3 covers the cylindrical hole opening at the upper end of the ceramic sleeve 4, and the upper end of the optical fiber ferrule 7 is inserted into the cylindrical hole opening at the lower end of the ceramic sleeve 4; the optical fiber 6 is inserted into the interior of the ceramic sleeve 4 through the optical fiber ferrule 7, and the FP cavity is formed by controlling the distance between the end face of the inserted optical fiber and the metal diaphragm 3;

[0031] like Figure 2 As shown, the lower end handle of the optical fiber ferrule 7 is inserted into the central hole of the fixed base 2, and the lower end of the optical fiber and the central hole of the fixed base are bonded and sealed by epoxy resin glue; the water-blocking cap 1 is hollow inside, with a circular opening at the lower end, a closed upper end, and the lower end is inserted into the circular groove of the fixed base 2, and the lower end of the water-blocking cap 1 and the edge of the circular groove of the fixed base 2 are bonded by epoxy resin, and sealed after liquid is injected; the probe composed of the ceramic sleeve 4, constant pressure hose 5, metal diaphragm 3, and optical fiber ferrule 7 is located in an independent sealed chamber formed by the water-blocking cap and the fixed base.

[0032] like Figure 2 As shown, under high-pressure environment, the independent sealed chamber formed by the water-blocking cap 1 and the fixed base 2 can protect the fragile sensor probe inside and isolate it from the external water environment to form the first line of high-pressure protection.

[0033] like Figure 2 As shown, under high-pressure environment, one end of the constant pressure hose 5 is inserted into the resonant cavity formed by the ceramic sleeve 4, the optical fiber ferrule 7 and the metal diaphragm 3, and the other end is exposed to the independent sealed chamber formed by the water-blocking cap 1 and the fixed base 2. The connecting pipe can maintain the pressure inside and outside the metal diaphragm 3 equal to prevent it from being destroyed by high pressure to form a second high-pressure protection.

[0034] like Figure 4 As shown, the spiral winding of the constant pressure hose 5 on the ceramic sleeve 4 is to increase the length of the communication channel to reduce the influence of the communication channel on the sensitivity of the hydrophone.

[0035] In actual tests, external sound waves pass through the waterproof cap 1 and the liquid in the cavity and are transmitted to the metal diaphragm 3, causing the metal diaphragm 3 to vibrate, thereby changing the distance between the center point of the metal diaphragm 3 and the end face of the optical fiber 7, causing the optical signal to change, thereby realizing the measurement of the sound wave signal.

[0036] Example 1:

[0037] The purpose of the present invention is to utilize the advantages of FP cavity fiber optic hydrophones. In view of the limitations of existing FP cavity fiber optic hydrophone probes, such as the diaphragm being easily dirty and fragile in harsh high-pressure environments, or being able to withstand high pressure but with high production costs, a new low-cost, high-pressure-resistant FP cavity fiber optic hydrophone probe structure device is proposed. This effectively combines the advantages of existing technologies to solve the problems of traditional FP cavity hydrophones' lack of high-pressure resistance and high production costs, providing strong guarantees for the large-scale application of FP cavity hydrophones in harsh deep-sea environments.

[0038] The present invention's compact overall structure makes it easier to integrate into precision vehicles such as deep-sea submarines, allowing it to operate in deep-sea environments. The vibrating diaphragm of a conventional FP cavity water device is easily contaminated by the marine environment, resulting in a decrease in light reflectivity and, consequently, sensitivity. Furthermore, to prevent contamination, the FP cavity must be sealed, leading to inconsistent pressures inside and outside the diaphragm under high-pressure conditions, potentially causing the diaphragm to rupture due to the pressure differential.

[0039] The present invention mainly relies on the waterproof cap 1 and the fixed base 2 to form an independent sealed chamber, and fills the independent sealed chamber with liquid, thereby providing an independent and clean working environment for the fragile sensor probe inside, isolating it from the external seawater environment, and preventing seawater from corroding and damaging the metal diaphragm 3.

[0040] The present invention mainly relies on the constant pressure hose 5 to achieve pressure balance inside and outside the metal diaphragm 3, and extends the constant pressure channel while reducing the volume of the sensor probe through a spiral winding design. This can ensure that the overall working state under high pressure is maintained while reducing the negative impact of the connecting hole on the performance of the hydrophone.

[0041] Optionally, in the hydrophone probe device of the present invention, a cylindrical boss is provided below the fixed base 2 , and the boss can be mounted on a corresponding adapter structure. The size parameters of the boss can be set according to actual needs.

[0042] During testing, the fixed base 2 is positioned with its boss facing downward, the rounded end of the watertight cap 1 pointing toward the sound source, and the optical fiber connected to the testing system. Sound waves pass through the watertight cap 1 and the liquid within it, reaching the metal diaphragm 3. This causes the diaphragm 3 to vibrate, changing the distance between the center of the diaphragm 3 and the end face of the optical fiber 7, thus altering the optical signal. The testing system detects this change in the optical signal and uses it to determine the characteristics of the acoustic signal.

[0043] Optionally, during high-pressure operation, the watertight cap 1 and fixed base 2 form a sealed chamber filled with liquid to withstand deep-sea pressure. The resonant cavity formed by the ceramic sleeve 4, fiber ferrule 7, and metal diaphragm 3 is kept dry and free of liquid, protecting the internal optical signal from liquid loss. Thus, the interior of the constant-pressure hose 5, with one end containing liquid and the other end containing air, maintains pressure equilibrium inside and outside the metal diaphragm 3.

[0044] The installation sequence of the overall device is: first, stick the metal diaphragm 3 to the ceramic sleeve 4 with epoxy resin, and then insert the optical fiber ferrule 7 into the bottom end of the ceramic sleeve 4; insert one end of the optical fiber 6 into the optical fiber ferrule 7 and adjust the position relative to the metal diaphragm 3; insert the tail handle of the optical fiber ferrule 7 into the center hole of the fixed base 2 and fix it with glue; insert one end of the constant pressure hose 5 into the side hole of the ceramic sleeve 4, and wrap the constant pressure hose 5 around the ceramic sleeve 4 and fix it with epoxy resin; finally, insert the water barrier 1 into the circular groove of the fixed base 2, inject water into the cavity of the water barrier 1 and seal it with epoxy resin.

[0045] Compared with the prior art, the above solution of the embodiment of the present invention has at least the following beneficial effects:

[0046] The hydrophone probe device provided by the present invention adopts a double high-voltage protection design, which can extend the working life of the hydrophone in a high-pressure environment and reduce the production cost of the hydrophone. It has a simple structure, high sensitivity, and great use value.

[0047] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A high-pressure-resistant FP cavity hydrophone probe device, characterized by: Including waterproof cap, fixed base, metal diaphragm, ceramic sleeve, constant pressure hose, optical fiber and optical fiber ferrule; The interior of the ceramic sleeve is cylindrical and hollow, with cylindrical holes openings at the centers of the upper and lower ends, and a circular hole also opened on the side of the cylinder and passing through one side wall; One end of the constant pressure hose is inserted into the side of the ceramic sleeve through the circular hole and is wound around the outside of the ceramic sleeve in a spiral line; The metal diaphragm covers the cylindrical hole opening at the upper end of the ceramic sleeve, and the upper end head of the optical fiber ferrule is inserted into the cylindrical hole opening at the lower end of the ceramic sleeve; The optical fiber is inserted into the interior of the ceramic sleeve through the optical fiber ferrule, and the FP cavity is formed by controlling the distance between the inserted optical fiber end face and the metal diaphragm; The lower end handle of the optical fiber ferrule is inserted into the central hole of the fixed base, and the lower end of the optical fiber and the central hole of the fixed base are bonded and sealed with epoxy resin glue; The water blocking cap is hollow inside, with a circular opening at the lower end and a closed upper end. The lower end is inserted into the circular groove of the fixed base, wherein the water blocking cap is filled with liquid, and the lower end of the water blocking cap and the edge of the circular groove of the fixed base are bonded and sealed with epoxy resin; The probe composed of the ceramic sleeve, constant pressure hose, metal diaphragm and optical fiber ferrule is located in an independent sealed chamber formed by a water-blocking cap and a fixed base; The bottom end of the water-blocking cap is inserted into the circular groove of the fixed base to form an independent sealed chamber. The optical fiber extends out of the independent sealed chamber through the central hole of the fixed base. Other structures are located in the independent sealed chamber. The water-blocking cap is sealed with the fixed base and filled with liquid to form an independent sealed chamber, one end of the optical fiber is located outside the independent sealed chamber, and the other end is located inside the independent sealed chamber; The optical fiber is located at one end of the independent sealed chamber, inserted into the ceramic sleeve through the optical fiber ferrule, and perpendicular to the metal diaphragm at the upper end of the ceramic sleeve; The upper end of the optical fiber ferrule is inserted into the cylindrical hole opening at the lower end of the ceramic sleeve, and the lower end of the optical fiber ferrule is inserted into the central hole of the fixed base. There is a cylindrical pipe in the middle of the optical fiber ferrule. The optical fiber is inserted into the interior of the ceramic sleeve through the cylindrical pipe and is perpendicular to the metal diaphragm. A circular hole is opened on the side of the ceramic sleeve, and one end of the constant pressure hose is inserted into the interior of the ceramic sleeve through the circular hole. The constant pressure hose body is spirally wound around the ceramic sleeve, and the other end of the constant pressure hose is placed in an independent sealed chamber formed by the water-blocking cap and the fixed base. The resonant cavity formed by the ceramic sleeve, the optical fiber ferrule and the metal diaphragm is filled with air.

2. The high-pressure-resistant FP cavity hydrophone probe device according to claim 1, characterized in that: One end of the constant pressure hose is located inside the ceramic sleeve, and the other end is located in an independent sealed chamber formed by the water-blocking cap and the fixed base. The liquid in the independent sealed chamber can enter the ceramic sleeve through the constant pressure hose.

3. The high-pressure-resistant FP cavity hydrophone probe device according to claim 1 or 2, characterized in that: The upper end of the ceramic sleeve is covered with a metal diaphragm, and the lower end is inserted with an optical fiber core. The interior of the ceramic sleeve is hollow to form an independent chamber, which is only connected to the independent sealed chamber formed by the water-blocking cap and the fixed base through a constant pressure hose.

4. The high-pressure-resistant FP cavity hydrophone probe device according to claim 1 or 3, characterized in that: The metal diaphragm is in a taut state, and the distance between the center of the metal diaphragm and the end face of the optical fiber is changed by vibration.

5. The high-pressure-resistant FP cavity hydrophone probe device according to claim 4, characterized in that: The optical fiber is a single-mode optical fiber; the ceramic sleeve is made of zirconia ceramic, and the cylindrical hole opening at the upper end of the ceramic sleeve is larger than the cylindrical hole opening at the lower end of the ceramic sleeve, thereby increasing the coverage area of ​​the metal diaphragm; the metal diaphragm is made of gold or aluminum; the optical fiber ferrule is an ordinary standard ferrule; the fixed base is made of stainless steel; the waterproof cap is made of polyurethane rubber and is sealed to the fixed base by epoxy resin glue.

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