Fiber grating based water-tight connector leakage and damage monitoring device and method

Abstract

The application discloses a kind of based on water-tight connector leakage and damage monitoring device and method of fiber grating.It comprises water-tight connector socket, water-tight connector plug and fiber grating sensor, water-tight connector plug is inserted into water-tight connector socket, fiber grating sensor is arranged in the monitoring hole of water-tight connector socket;Method includes: first install water-tight connector leakage and damage monitoring device, and connect with fiber grating demodulator, then check the center wavelength change of fiber grating deformation sensor and fiber grating humidity sensor detected on fiber grating demodulator, judge whether water-tight connector leakage and damage monitoring device is damaged and leakage occurs.The application realizes real-time, accurate monitoring of water-tight connector leakage and damage by using fiber grating sensor for water-tight connector monitoring, effectively overcomes the limitations of traditional manual inspection method.

Description

Technical Field

[0001] This invention relates to fiber optic sensing technology, and more particularly to a device and method for monitoring leakage and damage of watertight connectors based on fiber Bragg gratings, which is suitable for real-time monitoring of watertight connectors in underwater environments. Background Technology

[0002] Watertight connectors, as critical connection devices, are widely used in marine engineering, diving equipment, oil exploration, underwater robots, and other equipment that needs to operate in underwater environments. Due to the complexity and harshness of the underwater environment, watertight connectors must possess high reliability and durability. However, during prolonged use, watertight connectors are susceptible to various factors, such as high pressure, saltwater corrosion, and mechanical stress, leading to leakage, damage, or even failure.

[0003] Currently, leakage and damage detection of watertight connectors mainly relies on periodic manual inspections and maintenance. This method has several drawbacks: First, manual inspections need to be performed at specific times, making real-time monitoring impossible and potentially missing early signs of leakage and damage. Second, the underwater environment is complex and dangerous, making manual inspections difficult, costly, and posing safety hazards. Finally, the long intervals between periodic inspections prevent the timely detection and handling of sudden leakage and damage issues, potentially leaving equipment in a state of risk for extended periods, impacting the overall system's safety and reliability.

[0004] In recent years, with the development of fiber optic sensing technology, fiber Bragg grating (FBG)-based sensors have been widely used in various monitoring fields. FBG sensors possess advantages such as high sensitivity, resistance to electromagnetic interference, small size, and ease of integration, making them ideal for monitoring underwater environments. By detecting changes in the wavelength of the FBG, changes in environmental parameters, such as temperature, stress, and pressure, can be accurately sensed, thereby achieving real-time monitoring of equipment status. Although FBG sensors have achieved certain applications in other fields, research and application in monitoring leakage and damage to watertight connectors are still relatively limited. Therefore, there is an urgent need for a device and method for monitoring leakage and damage to watertight connectors based on FBG technology to overcome the shortcomings of existing technologies, achieve real-time and accurate monitoring of watertight connectors, and ensure the safe and stable operation of underwater equipment. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a device and method for monitoring leakage and damage to watertight connectors based on fiber Bragg gratings. This device can monitor leakage and damage to watertight connectors in real time in underwater environments. By integrating a fiber Bragg grating sensor, the device can detect changes in watertight connector parameters (deformation, humidity) and thus determine the connector's condition. Compared to traditional manual inspection methods, this fiber Bragg grating-based monitoring system offers advantages such as high real-time performance, high sensitivity, and high security.

[0006] The technical solution adopted in this invention is as follows:

[0007] The present invention provides a watertight connector leakage and damage monitoring device based on fiber Bragg grating, comprising:

[0008] The device comprises a watertight connector socket, a watertight connector plug, and a fiber Bragg grating sensor. The watertight connector plug is inserted into the watertight connector socket. A mating structure for installing the fiber Bragg grating sensor is provided between the monitoring hole of the watertight connector socket and the monitoring hole plug of the watertight connector plug. The fiber Bragg grating sensor is arranged in the monitoring hole of the watertight connector socket to monitor whether there is water leakage or damage to the connection between the watertight connector plug and the watertight connector socket.

[0009] The watertight connector socket includes several insertion holes and a monitoring hole; the insertion holes are used for photoelectric signal transmission, and a fiber optic grating sensor is arranged inside the monitoring hole.

[0010] The watertight connector plug includes several pins and a monitoring hole plug; the pins are used to insert into the connector hole and match the connector hole for photoelectric signal transmission, and the monitoring hole plug is used to insert into the monitoring hole for sealing.

[0011] The fiber Bragg grating sensor includes an optical fiber, sealant, a fiber Bragg grating deformation sensor, a fiber Bragg grating humidity sensor, and a humidity-sensitive material. The optical fiber is arranged inside the monitoring hole of a watertight connector socket, and the input and output ends of the optical fiber are connected to a fiber Bragg grating demodulator. The fiber Bragg grating deformation sensor is fixed in the wall of the monitoring hole by sealant, and the fiber Bragg grating deformation sensor is in close contact with the wall of the monitoring hole. The humidity-sensitive material is coated on the outer surface of the grating area of ​​the fiber Bragg grating humidity sensor, and the humidity-sensitive material is exposed to the air inside the monitoring hole.

[0012] The fiber Bragg grating deformation sensor and the fiber Bragg grating humidity sensor are sequentially integrated on the same optical fiber along the direction of the light emitted by the fiber Bragg grating demodulator; both the fiber Bragg grating deformation sensor and the fiber Bragg grating humidity sensor are integrated at one end of the optical fiber near the watertight connector plug; both the fiber Bragg grating deformation sensor and the fiber Bragg grating humidity sensor are obtained by locally exposing the optical fiber to ultraviolet light.

[0013] The monitoring method of the watertight connector leakage and damage monitoring device of the present invention includes:

[0014] 1) Install the watertight connector leakage and damage monitoring device and connect it to the fiber optic demodulator;

[0015] 2) Check the center wavelength change of the fiber grating deformation sensor detected on the fiber grating demodulator to determine whether the watertight connector leakage and damage monitoring device has been damaged;

[0016] 3) Check the change in the center wavelength of the fiber optic grating humidity sensor detected by the fiber optic grating demodulator to determine whether the watertight connector leakage and damage monitoring device has leaked.

[0017] Step 1) specifically refers to:

[0018] 1.1) The fiber optic grating deformation sensor and the fiber optic grating humidity sensor are sequentially integrated on the same optical fiber along the direction of the emitted light of the fiber optic grating demodulator. Both the fiber optic grating deformation sensor and the fiber optic grating humidity sensor are integrated at one end of the optical fiber near the watertight connector plug.

[0019] 1.2) Coat the outer surface of the grating region of the fiber optic humidity sensor with a humidity-sensitive material and expose the humidity-sensitive material to the air inside the monitoring aperture;

[0020] 1.3) Fix the fiber Bragg grating deformation sensor in the monitoring hole wall with sealant to ensure that the fiber Bragg grating deformation sensor and the monitoring hole wall are in close contact;

[0021] 1.4) Connect the input and output ends of the optical fiber to the fiber optic demodulator.

[0022] The criteria for judgment in step 2) are:

[0023] When the change in the center wavelength of the fiber Bragg grating deformation sensor displayed by the fiber Bragg grating demodulator is greater than or equal to the preset deformation threshold, the watertight connector leakage and damage monitoring device is damaged; when the change in the center wavelength of the fiber Bragg grating deformation sensor displayed by the fiber Bragg grating demodulator is less than the preset deformation threshold, the watertight connector leakage and damage monitoring device is not damaged.

[0024] The criteria for judgment in step 3) are:

[0025] When the change in the center wavelength of the fiber Bragg grating humidity sensor per unit time, as displayed by the fiber Bragg grating demodulator, is greater than or equal to the preset leakage threshold, leakage and damage monitoring device for the watertight connector occurs; when the change in the center wavelength of the fiber Bragg grating humidity sensor per unit time, as displayed by the fiber Bragg grating demodulator, is less than the preset leakage threshold, leakage and damage monitoring device for the watertight connector does not occur.

[0026] In practice, the deformation preset threshold and the leakage preset threshold are set according to the actual use environment, material characteristics and detection accuracy requirements.

[0027] The beneficial effects of this invention are:

[0028] By employing fiber Bragg grating-based monitoring technology, real-time and accurate detection of leakage and damage to watertight connectors is achieved, effectively overcoming the limitations of traditional manual inspection methods. Its high sensitivity enables early detection of potential faults, avoiding serious consequences due to delayed detection. Furthermore, the device's compact structure facilitates integration with existing systems, enhancing the operational safety and reliability of underwater equipment while reducing maintenance costs and operational risks, providing strong technical support for the application of watertight connectors in complex underwater environments. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the watertight connector leakage and damage monitoring device of the present invention;

[0030] Figure 2 This is a schematic diagram of the design of the watertight connector socket of the present invention;

[0031] Figure 3 This is a schematic diagram of the watertight connector plug design of the present invention;

[0032] Figure 4 This is a schematic diagram of an embedded fiber optic grating sensor in the watertight connector socket of the present invention.

[0033] In the diagram, 1. Watertight connector socket; 2. Fiber Bragg grating sensor; 3. Watertight connector plug; 4. Socket; 5. Monitoring hole; 6. Pin; 7. Monitoring hole plug; 8. Optical fiber; 9. Sealant; 10. Fiber Bragg grating deformation sensor; 11. Fiber Bragg grating humidity sensor; 12. Humidity-sensitive material. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, this device includes a specially designed watertight connector socket 1, a specially designed watertight connector plug 3, and a fiber Bragg grating sensor 2. The watertight connector plug 3 is inserted into the watertight connector socket 1. A mating structure for installing the fiber Bragg grating sensor 2 is provided between the monitoring hole 5 of the watertight connector socket 1 and the monitoring hole plug 7 of the watertight connector plug 3. The fiber Bragg grating sensor 2 is arranged in the monitoring hole 5 of the watertight connector socket 1 and is used to monitor in real time whether there is water leakage or damage to the connection part between the watertight connector plug 3 and the watertight connector socket 1 when the watertight connector plug 3 is inserted into the watertight connector socket 1.

[0036] like Figure 2 As shown, the watertight connector socket 1 includes several insertion holes 4 and a monitoring hole 5; the insertion holes 4 are used for normal photoelectric signal transmission, and the monitoring hole 5 is equipped with a fiber optic grating sensor 2.

[0037] like Figure 3 As shown, the watertight connector plug 3 includes several pins 6 and a monitoring hole plug 7; the pins 6 are used to insert into the connector hole 4 and match the connector hole 4 for normal photoelectric signal transmission, and the monitoring hole plug 7 is used to insert into the monitoring hole 5 to seal the monitoring hole 5. The monitoring hole plug 7 is inserted into the gap between the fiber optic grating humidity sensor 11 and the wall of the monitoring hole 5, thereby sealing the connection between the watertight connector plug 3 and the watertight connector socket 1.

[0038] like Figure 4As shown, the fiber Bragg grating sensor 2 includes an optical fiber 8, sealant 9, a fiber Bragg grating deformation sensor 10, a fiber Bragg grating humidity sensor 11, and a humidity-sensitive material 12. The optical fiber 8 is arranged inside the monitoring hole 5 of the watertight connector socket 1, and its input / output ends are connected to the fiber Bragg grating demodulator. The fiber Bragg grating deformation sensor 10 is fixed to the wall of the monitoring hole 5 by the sealant 9, and the fiber Bragg grating deformation sensor 10 is in close contact with the wall of the monitoring hole 5. When the watertight connector leakage and damage monitoring device is damaged and deformed, the center wavelength of the fiber Bragg grating deformation sensor 10 will change, thereby determining whether the watertight connector leakage and damage monitoring device has been damaged. The humidity-sensitive material 12 is coated on the outer surface of the grating area of ​​the fiber Bragg grating humidity sensor 11. The humidity-sensitive material 12 is exposed to the air inside the monitoring hole 5. When the watertight connector leakage and damage monitoring device leaks, the humidity-sensitive material 12 will deform due to the increase in humidity, thereby causing a change in the center wavelength of the fiber Bragg grating humidity sensor 11, thereby determining whether the watertight connector leakage and damage monitoring device has leaked.

[0039] Fiber Bragg grating deformation sensor 10 and fiber Bragg grating humidity sensor 11 are sequentially integrated at intervals on the same optical fiber 8 along the direction of light emission from the fiber Bragg grating demodulator. Both the fiber Bragg grating deformation sensor 10 and the fiber Bragg grating humidity sensor 11 are integrated at one end of the optical fiber 8 closest to the watertight connector plug 3. The closer the fiber Bragg grating humidity sensor 11 is to the watertight connector plug 3, the better. The fiber Bragg grating deformation sensor 10 is closer to the side integrated with the fiber Bragg grating humidity sensor 11. Both the fiber Bragg grating deformation sensor 10 and the fiber Bragg grating humidity sensor 11 are obtained by locally exposing a portion of the optical fiber 8 to ultraviolet light.

[0040] Monitoring workflow of the watertight connector leakage and damage monitoring device:

[0041] The fiber optic demodulator sends an optical signal, which is transmitted along fiber optic cable 8 and arrives sequentially at fiber optic deformation sensor 10 and fiber optic humidity sensor 11.

[0042] When the connection between the watertight connector plug 3 and the watertight connector socket 1 is damaged, the fiber optic grating deformation sensor 10 detects the damage and the center wavelength of the fiber optic grating deformation sensor 10 changes; when the connection between the watertight connector plug 3 and the watertight connector socket 1 is not damaged, the fiber optic grating deformation sensor 10 does not detect the damage and the center wavelength of the fiber optic grating deformation sensor 10 does not change.

[0043] When there is leakage at the connection between the watertight connector plug 3 and the watertight connector socket 1, the fiber optic grating deformation sensor 10 detects the leakage, and the center wavelength of the fiber optic grating humidity sensor 11 changes; when there is no leakage at the connection between the watertight connector plug 3 and the watertight connector socket 1, the fiber optic grating deformation sensor 10 does not detect the leakage, and the center wavelength of the fiber optic grating humidity sensor 11 does not change.

[0044] The optical signals from the fiber Bragg grating deformation sensor 10 and the fiber Bragg grating humidity sensor 11 are returned to the fiber Bragg grating demodulator. The fiber Bragg grating demodulator demodulates the optical signals and analyzes the fluctuations in the center wavelength to determine whether the watertight connector leakage and damage monitoring device has been damaged or leaking.

[0045] The center wavelength of the fiber Bragg grating deformation sensor 10 refers to the center wavelength of the echo signal received by the fiber Bragg grating demodulator after the light emitted from the fiber Bragg grating demodulator propagates along the fiber optic cable 8 to the fiber Bragg grating deformation sensor 10 and is then reflected back to the fiber Bragg grating demodulator. Similarly, the center wavelength of the fiber Bragg grating humidity sensor 11 also refers to the center wavelength of the echo signal received by the fiber Bragg grating demodulator after the light emitted from the fiber Bragg grating demodulator propagates along the fiber optic cable 8 to the fiber Bragg grating humidity sensor 11 and is then reflected back to the fiber Bragg grating demodulator.

[0046] The embodiments and steps of the present invention are as follows:

[0047] 1) Install a watertight connector leakage and damage monitoring device and connect it to a fiber optic demodulator;

[0048] 1.1) The fiber Bragg grating deformation sensor 10 and the fiber Bragg grating humidity sensor 11 are sequentially and spaced apart on the same optical fiber 8 along the direction of the emitted light of the fiber Bragg grating demodulator. The fiber Bragg grating deformation sensor 10 and the fiber Bragg grating humidity sensor 11 are both integrated at one end of the optical fiber 8 near the watertight connector plug 3.

[0049] 1.2) Coat the outer surface of the grating region of the fiber optic humidity sensor 11 with a humidity-sensitive material 12 and expose the humidity-sensitive material 12 to the air inside the monitoring hole 5;

[0050] 1.3) Fix the fiber optic grating deformation sensor 10 to the wall of the monitoring hole 5 with sealant 9 so that the fiber optic grating deformation sensor 10 and the wall of the monitoring hole 5 are in close contact.

[0051] 1.4) Connect the input and output ends of fiber optic cable 8 to the fiber optic demodulator.

[0052] 2) Check the center wavelength change of the fiber optic grating deformation sensor 10 detected on the fiber optic grating demodulator to determine whether the watertight connector leakage and damage monitoring device has been damaged.

[0053] When the change in the center wavelength of the fiber optic grating deformation sensor 10 displayed by the fiber optic grating demodulator is greater than or equal to the preset deformation threshold, the watertight connector leakage and damage monitoring device is damaged; when the change in the center wavelength of the fiber optic grating deformation sensor 10 displayed by the fiber optic grating demodulator is less than the preset deformation threshold, the watertight connector leakage and damage monitoring device is not damaged.

[0054] 3) Check the change in the center wavelength of the fiber optic grating humidity sensor 11 detected by the fiber optic grating demodulator to determine whether the watertight connector leakage and damage monitoring device has leaked.

[0055] When the change in the center wavelength of the fiber optic grating humidity sensor 11 displayed by the fiber optic grating demodulator is greater than or equal to the preset leakage threshold, the watertight connector leakage and damage monitoring device leaks; when the change in the center wavelength of the fiber optic grating humidity sensor 11 displayed by the fiber optic grating demodulator is less than the preset leakage threshold, the watertight connector leakage and damage monitoring device does not leak.

[0056] In practice, the deformation preset threshold and the leakage preset threshold are set according to the actual use environment, material characteristics and detection accuracy requirements.

[0057] This invention integrates a fiber Bragg grating sensor to monitor changes in watertight connector parameters (deformation, humidity) in real time, thereby determining the connector's condition and ensuring its safe operation. This effectively overcomes the limitations of traditional manual inspection methods. Its high sensitivity enables early detection of potential faults, avoiding serious consequences due to delayed detection. Furthermore, the device's compact structure facilitates integration with existing systems, enhancing the operational safety and reliability of underwater equipment while reducing maintenance costs and operational risks. This provides strong technical support for the application of watertight connectors in complex underwater environments.

[0058] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fiber grating-based water-tight connector leakage and damage monitoring device, characterized in that: it comprises a water-tight connector socket (1), a water-tight connector plug (3), and a fiber grating sensor (2); the water-tight connector plug (3) is inserted into the water-tight connector socket (1), and a matching structure for installing the fiber grating sensor (2) is arranged between the monitoring hole (5) of the water-tight connector socket (1) and the monitoring hole plug (7) of the water-tight connector plug (3); the fiber grating sensor (2) is arranged in the monitoring hole (5) of the water-tight connector socket (1) to monitor whether there is water leakage and damage to the connection part between the water-tight connector plug (3) inserted into the water-tight connector socket (1). The water-tight connector socket (1) comprises a plurality of plug-in holes (4) and a monitoring hole (5); the plug-in holes (4) are used for optical signal transmission, and the monitoring hole (5) is arranged with the fiber grating sensor (2). The water-tight connector plug (3) comprises a plurality of pins (6) and a monitoring hole plug (7); the pins (6) are used for insertion into the plug-in holes (4) and matching with the plug-in holes (4) for optical signal transmission, and the monitoring hole plug (7) is used for insertion into the monitoring hole (5) for sealing. The fiber grating sensor (2) comprises an optical fiber (8), a sealing glue (9), a fiber grating deformation sensor (10), a fiber grating humidity sensor (11), and a humidity-sensitive material (12); the optical fiber (8) is arranged inside the monitoring hole (5) of the water-tight connector socket (1), and the input and output ends of the optical fiber (8) are connected with a fiber grating demodulator; the fiber grating deformation sensor (10) is fixed in the hole wall of the monitoring hole (5) through the sealing glue (9), and the fiber grating deformation sensor (10) is in close contact with the hole wall of the monitoring hole (5); the humidity-sensitive material (12) is coated on the outer surface of the grating area of the fiber grating humidity sensor (11), and the humidity-sensitive material (12) is exposed to the air inside the monitoring hole (5).

2. The water-tight connector leakage and damage monitoring device according to claim 1, characterized in that: the fiber grating deformation sensor (10) and the fiber grating humidity sensor (11) are integrated on the same optical fiber (8) in sequence along the direction of light emission of the fiber grating demodulator; the fiber grating deformation sensor (10) and the fiber grating humidity sensor (11) are both integrated on one end of the optical fiber (8) close to the water-tight connector plug (3); the fiber grating deformation sensor (10) and the fiber grating humidity sensor (11) are both obtained by ultraviolet exposure of a local part of the optical fiber (8). The method steps are as follows: 1) Install the water-tight connector leakage and damage monitoring device and connect it with a fiber grating demodulator; 3. The monitoring method applied to the leakage and damage monitoring device of any one of claims 1-2, characterized in that: 2) Check the change of the center wavelength of the fiber grating deformation sensor (10) detected on the fiber grating demodulator to determine whether the water-tight connector leakage and damage monitoring device is damaged. ​ ​ 3) Check the change of the center wavelength of the fiber grating humidity sensor (11) detected on the fiber grating demodulator to determine whether the water-tight connector leakage and damage monitoring device has leaked.

4. The monitoring method of the water-tight connector leakage and damage monitoring device according to claim 3, wherein: the step 1) is specifically: 1.1) The fiber grating deformation sensor (10) and the fiber grating humidity sensor (11) are integrated on the same optical fiber (8) in sequence along the direction of the light emitted by the fiber grating demodulator, and the fiber grating deformation sensor (10) and the fiber grating humidity sensor (11) are both integrated on one end of the optical fiber (8) close to the water-tight connector plug (3); 1.2) The surface of the grating area of the fiber grating humidity sensor (11) is coated with a humidity-sensitive material (12), and the humidity-sensitive material (12) is exposed to the air inside the monitoring hole (5); 1.3) The fiber grating deformation sensor (10) is fixed in the hole wall of the monitoring hole (5) by the sealing glue (9), so that the fiber grating deformation sensor (10) and the hole wall of the monitoring hole (5) are tightly attached; 1.4) The input and output ends of the optical fiber (8) are connected with the fiber grating demodulator.

5. The monitoring method of the water-tight connector leakage and damage monitoring device according to claim 3, wherein: the standard for judging in the step 2) is: when the unit time change amount of the center wavelength of the fiber grating deformation sensor (10) displayed by the fiber grating demodulator is greater than or equal to the deformation preset threshold, the water-tight connector leakage and damage monitoring device is damaged; when the unit time change amount of the center wavelength of the fiber grating deformation sensor (10) displayed by the fiber grating demodulator is less than the deformation preset threshold, the water-tight connector leakage and damage monitoring device is not damaged.

6. The monitoring method of the water-tight connector leakage and damage monitoring device according to claim 3, wherein: the standard for judging in the step 3) is: when the unit time change amount of the center wavelength of the fiber grating humidity sensor (11) displayed by the fiber grating demodulator is greater than or equal to the liquid leakage preset threshold, the water-tight connector leakage and damage monitoring device has leaked; when the unit time change amount of the center wavelength of the fiber grating humidity sensor (11) displayed by the fiber grating demodulator is less than the liquid leakage preset threshold, the water-tight connector leakage and damage monitoring device has not leaked.

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