A device for optical observation of sediment concentration with integrated active and passive anti-biofouling

Abstract

The application discloses a kind of integrated active and passive anti-biofouling optical observation device containing sand content, including device main body, the inside of the device main body is equipped with optical measurement unit, control unit, communication unit, replaceable shell mechanism, ultraviolet active irradiation anti-biofouling mechanism, ultraviolet water circulation liquid cooling heat dissipation mechanism, copper ion active release anti-biofouling mechanism, electrode consumption sensing mechanism and underwater visual pollution monitoring mechanism.The scheme constructs multi-layer protection, intelligent monitoring and time sequence heat dissipation integrated comprehensive system, solves the defects of traditional sand measuring device, adapts to long-term underwater monitoring of high-sand water body, has the advantages of high precision, low operation and maintenance, energy saving and environmental protection and high intelligence, and has outstanding engineering popularization value.

Description

Technical Field

[0002] This invention relates to the field of hydrological sediment measurement technology, specifically to an optical observation device for sediment content that integrates active and passive anti-bioattachment mechanisms. Background Technology

[0003] Sediment concentration is a crucial component of basic hydrological data collection, holding significant value for river sediment management, soil and water conservation monitoring, reservoir siltation assessment, and hydraulic engineering design. Traditional methods of collecting water samples, drying, and weighing them are no longer sufficient to meet the timeliness and continuity requirements of modern hydrological monitoring. In recent years, online sediment concentration measurement technology based on optical principles has been widely adopted. Optical measurement methods utilize the inherent optical properties of suspended sediment particles, such as light attenuation and backscattering, to achieve rapid and continuous monitoring of suspended sediment concentration.

[0004] However, underwater optical observation devices face a common problem in practical applications: biofouling. Most instruments and equipment used in marine environmental monitoring are placed in seawater and are inevitably affected to varying degrees by marine organisms attaching to them. These organisms can grow very rapidly, covering the measurement units of observation equipment and sensors, adversely affecting measurement results, causing continuous data drift, reduced data quality, and eventually sensor failure. In particular, the optical windows of underwater sensors are highly susceptible to biofouling, leading to severely inaccurate data acquisition.

[0005] To address the biofouling problem of underwater optical windows, common anti-biofouling measures include toxic coatings, mechanical cleaning, and ultraviolet radiation. However, these measures have different limitations: toxic coatings pose environmental pollution risks, mechanical cleaning requires frequent manual intervention, and ultraviolet radiation alone is energy-intensive under long-term continuous irradiation and has limited effectiveness against some stubborn biofouling organisms. Some researchers have also used electrochemical constant potential electrolysis to generate bactericidal substances such as hypochlorous acid by electrolyzing seawater to prevent biofouling, or used nanostructured surface materials as anti-biofouling windows. However, these methods often only solve the problem of biofouling at a single stage and lack a comprehensive anti-biofouling solution for optical observation devices, from passive protection and active protection to intelligent monitoring, especially lacking a comprehensive anti-biofouling design for the specific application scenario of sediment concentration measurement.

[0006] In optical sediment concentration monitoring devices, the measurement environment often contains high concentrations of suspended sediment. The deposition of sediment particles on the device surface accelerates biofilm adhesion and growth, further complicating the prevention of biofilm formation. Furthermore, sediment concentration measurement places strict requirements on the transmittance of the optical window; any contamination directly affects measurement accuracy. Therefore, there is an urgent need for an optical sediment concentration monitoring device suitable for sediment-laden water environments, integrating multiple anti-biofilm measures and possessing intelligent monitoring capabilities.

[0007] Therefore, a solution is needed. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides an optical observation device for sand content that integrates active and passive anti-bioattachment techniques, thereby solving the problems mentioned in the background section.

[0009] To achieve the above objectives, the present invention provides the following technical solution: An optical observation device for sediment content that integrates active and passive anti-bioattachment mechanisms includes a main body, which contains an optical measurement unit, a control unit, a communication unit, a replaceable outer shell, an active ultraviolet irradiation anti-bioattachment mechanism, an ultraviolet water circulation liquid cooling heat dissipation mechanism, an active copper ion release anti-bioattachment mechanism, an electrode consumption sensing mechanism, and an underwater visual turbidity monitoring mechanism. The replaceable outer shell mechanism includes an inner waterproof sealing shell, an outer replaceable protective shell, and a detachable connection structure. The inner waterproof sealing shell is disposed outside the main body of the device. The outer replaceable protective shell is assembled to the outside of the inner waterproof sealing shell through the detachable connection structure. The outer replaceable protective shell is made of a bio-attachment inhibitory material. The ultraviolet active irradiation anti-bioattachment mechanism includes an optical window, an ultraviolet LED array, an ultraviolet driving circuit, and an irradiation timing controller. The optical window is located at the optical measurement front end of the main body of the device. The ultraviolet LED array is arranged around the optical window. The ultraviolet driving circuit is electrically connected to the ultraviolet LED array. The irradiation timing controller is signal-connected to both the optical measurement unit and the ultraviolet driving circuit. The irradiation timing controller turns on ultraviolet irradiation during non-measurement periods and turns off ultraviolet irradiation during measurement periods. Both the ultraviolet driving circuit and the irradiation timing controller are integrated inside the control unit. The ultraviolet (UV) water circulation liquid cooling mechanism includes a heat sink module, a circulating water pump, liquid cooling pipes, and external heat dissipation fins. The heat sink module is attached to the back of the UV LED array to conduct heat generated by the UV LED array during operation. The circulating water pump is connected to the heat sink module through the liquid cooling pipes to provide power for the circulation of coolant. The liquid cooling pipes connect the heat sink module and the external heat dissipation fins to form a closed heat exchange loop. The external heat dissipation fins receive the heat carried by the coolant through the liquid cooling pipes and dissipate the heat into the external water body, indirectly cooling the UV LED array. The heat sink module, circulating water pump, liquid cooling pipes, and external heat dissipation fins form a closed water circulation cooling loop. The copper ion active release anti-bioattachment mechanism includes a copper anode electrode, an auxiliary electrode, a constant current control circuit, and an ion release timing controller. The constant current control circuit is electrically connected to both the copper anode electrode and the auxiliary electrode. Both the copper anode electrode and the auxiliary electrode are located on the outside of the inner waterproof sealing shell, directly in contact with the water, and rely on low-pressure electrolysis to slowly release trace amounts of copper ions into the surrounding water to achieve biorepellency. The ion release timing controller is signal-connected to the constant current control circuit to control the intermittent output of electrolysis current by the constant current control circuit. The ion release timing controller is integrated inside the control unit. The electrode consumption sensing mechanism includes a consumption sensing sensor and an alarm communication module. The consumption sensing sensor is embedded inside the copper anode electrode, and the alarm communication module is integrated inside the control unit. The alarm communication module is connected to the consumption sensing sensor and the communication unit respectively. When the copper anode electrode is worn down to a preset threshold, an alarm is triggered. The consumption sensing sensor and the alarm communication module together constitute the electrode consumption sensing mechanism. The underwater visual pollution monitoring mechanism includes a miniature camera, a timed image capture control module, and an image intelligent analysis module. The miniature camera is located inside the main body of the device. The timed image capture control module and the image intelligent analysis module are both integrated inside the control unit. The timed image capture control module is signal-connected to the miniature camera, and the image intelligent analysis module is signal-connected to both the timed image capture control module and the communication unit. The miniature camera periodically captures images from the optical window. The timed image capture control module and the image intelligent analysis module identify the degree of pollution. If the pollution exceeds the standard, an intelligent alarm is triggered.

[0010] Preferably, the replaceable outer protective shell is made of a transparent polymer material with a nanoscale surface microstructure. The micro-nano structure reduces the contact area for microbial attachment, and the entire shell can be disassembled and replaced individually to reduce underwater maintenance costs.

[0011] Preferably, the optical window is made of sapphire glass or quartz glass; the ultraviolet LED array uses UV-C band ultraviolet LEDs with a wavelength of 200-280nm, and multiple LEDs are evenly arranged around the optical window.

[0012] Preferably, the heat sink module is made of a metal material with high thermal conductivity and has a serpentine liquid cooling channel inside; the coolant circulates in a closed loop formed by the heat sink module, the circulating water pump, the liquid cooling pipeline and the external heat dissipation fins. After the coolant flows through the heat sink module to absorb the working heat of the ultraviolet LED array, it conducts the heat to the external water body through the external heat dissipation fins to avoid premature decay of the LED at high temperature.

[0013] Preferably, the copper anode electrode is made of electrolytic copper with a purity of ≥99.9%; the auxiliary electrode is a carbon electrode; and the constant current control circuit outputs an adjustable constant current within the range of 1 to 10 mA.

[0014] Preferably, the consumption sensing sensor is a resistive sensing element and is embedded in the copper anode electrode at a preset depth; when electrolytic consumption causes the copper anode electrode to wear down to the preset depth, the sensor circuit resistance of the consumption sensing sensor changes abruptly, and an alarm signal is output to the alarm communication module.

[0015] Preferably, the control unit controls each subsystem to operate in a coordinated manner according to a preset timing sequence; the measurement timing sequence and the ultraviolet irradiation timing sequence are performed alternately, and the copper ion electrolytic discharge and the image acquisition of the miniature camera are both executed according to a preset cycle. When the ultraviolet LED array is working, the water circulation liquid cooling heat dissipation device is started synchronously, and the water pump stops after a delay after the ultraviolet light is turned off to remove the residual heat.

[0016] Preferably, the image intelligent analysis module uses a deep learning-based dirt recognition model to analyze the dirt level of the image of the optical window captured by the miniature camera, calculates the ratio of the area of ​​the light-transmitting region to the total area of ​​the optical window, and triggers an alarm when the ratio is lower than a preset threshold.

[0017] Preferably, the communication unit supports wired and wireless dual-mode communication; the communication unit uploads real-time sand content measurement data, the consumption status of the copper anode electrode, the degree of turbidity of the optical window, and operational fault information of each subsystem to the remote monitoring platform.

[0018] Preferably, the inner waterproof sealing shell is made of 316L stainless steel. An O-ring is provided at the connection between the inner waterproof sealing shell and the main body of the device. A positioning boss is provided on the side of the inner waterproof sealing shell facing the outer replaceable protective shell. A positioning groove is provided on the side of the outer replaceable protective shell corresponding to the positioning boss. A light-transmitting hole is provided on the outer replaceable protective shell corresponding to the position of the optical window. An annular sealing groove is provided around the light-transmitting hole. The detachable connection structure adopts a snap-fit ​​assembly structure, which facilitates quick underwater disassembly and replacement of the outer replaceable protective shell.

[0019] This invention provides an optical observation device for sand content that integrates active and passive anti-bioattachment techniques. It offers the following advantages: 1. Integrated Active and Passive Biofouling Protection: Passive protection is achieved through a replaceable outer biofouling shell, while active protection is achieved through UV irradiation and the active release of copper ions, forming a multi-layered biofouling barrier. Passive protection reduces the initial biofouling probability, while active protection inhibits the growth of already attached microorganisms. The synergistic effect of both significantly improves the biofouling prevention effect. The outer shell is made of an environmentally friendly polymer material with a nanostructure, which reduces sediment deposition and inhibits biofilm growth at its source. The double-shell quick-release structure allows for easy replacement underwater.

[0020] 2. Intelligent Maintenance Management: Through electrode consumption sensors and an underwater visual pollution monitoring system, the system enables online self-diagnosis and intelligent alarms for the device's status, transforming passive maintenance into proactive early warning, reducing maintenance costs, and improving the reliability and availability of the device. Remote alarms can be pushed for issues such as excessive electrode wear and insufficient light transmittance of the optical window, eliminating the need for regular manual underwater inspections.

[0021] 3. Energy saving and environmental protection: Ultraviolet irradiation is only turned on during non-measurement periods, and the matching liquid cooling circuit delays heat dissipation to reduce the energy consumption of optoelectronic devices; copper ion release adopts micro-pulse electrolysis to avoid the potential environmental impact of continuous large-scale release; the anti-biofouling shell is made of environmentally friendly anti-biofouling material, with no toxic agents released, meeting green environmental protection requirements.

[0022] 4. Suitable for sandy water environments: The replaceable shell design makes it easy to replace the damaged shell in the abrasive environment of silt and sand, extending the overall life of the device; the liquid cooling system directly utilizes the natural heat dissipation of the external water body, eliminating vulnerable rotating parts such as fans underwater, and the closed-loop structure resists silt corrosion, making it suitable for long-term continuous underwater operation.

[0023] 5. High measurement accuracy: Multiple anti-biofouling measures ensure that the optical window maintains high light transmittance over a long period of time. At the same time, time-separated measurement, ultraviolet and copper ion release working periods avoid interference caused by light and ion scattering, avoid measurement errors caused by biofouling, and improve the long-term stability and accuracy of sand content measurement.

[0024] 6. Longer equipment lifespan and lower maintenance costs: The liquid cooling structure quickly dissipates the heat from the UV LEDs, delaying high-temperature aging of the devices; the copper electrolytic electrodes can work in pairs alternately, extending the single replacement cycle; protection capabilities can be restored by replacing only the damaged outer shell, without replacing the core optical measurement components, significantly reducing long-term maintenance material and labor costs.

[0025] 7. Adaptable to unattended remote monitoring: The device supports wired and wireless dual-mode communication and can be connected to a remote monitoring platform to synchronously upload all operational information such as sediment content data, electrode wear, window turbidity, and equipment failure, making it suitable for automated hydrological monitoring scenarios in various nearshore and remote waters. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the optical observation device for sand content that integrates active and passive anti-bioattachment mechanisms according to the present invention.

[0027] Figure 2 This is a schematic diagram of the replaceable housing system in the device of the present invention.

[0028] Figure 3 This is a schematic diagram of the structure of the ultraviolet active irradiation anti-bioattachment system and the liquid cooling heat dissipation system in the device of the present invention.

[0029] Figure 4 This is a schematic diagram of the structure of the copper ion active release anti-bioattachment system in the device of the present invention.

[0030] Figure 5 This is a timing diagram of the operation of each subsystem in the device of the present invention.

[0031] Figure 6 This is a system block diagram of the device of the present invention.

[0032] 1-Main body of the device; 2-Optical measurement unit; 3-Control unit; 4-Communication unit; 5-Replaceable outer shell mechanism; 51-Inner waterproof sealing shell; 511-O-ring seal; 512-Positioning boss; 52-Outer replaceable protective shell; 521-Positioning groove; 522-Light transmission hole; 523-Annular sealing groove; 53-Detachable connection structure; 6-Ultraviolet active irradiation anti-bioattachment mechanism; 61-Optical window; 62-Ultraviolet LED array; 63-Ultraviolet driving circuit; 64-Irradiation timing controller; 7-Ultraviolet... 71-Water circulation liquid cooling heat dissipation mechanism; 72-Circulating water pump; 73-Liquid cooling pipeline; 74-External heat dissipation fins; 8-Copper ion active release anti-bioattachment mechanism; 81-Copper anode electrode; 82-Auxiliary electrode; 83-Constant current control circuit; 84-Ion release timing controller; 9-Electrode consumption sensing mechanism; 91-Consumption sensing sensor; 92-Alarm communication module; 10-Underwater visual pollution monitoring mechanism; 101-Miniature camera; 102-Timed photo capture control module; 103-Intelligent image analysis module. 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] Please see Figure 1-6 The present invention provides a technical solution to achieve this: it includes a device body 1, and the device body 1 is provided with an optical measurement unit 2, a control unit 3, a communication unit 4, a replaceable shell mechanism 5, an ultraviolet active irradiation anti-bioattachment mechanism 6, an ultraviolet water circulation liquid cooling heat dissipation mechanism 7, a copper ion active release anti-bioattachment mechanism 8, an electrode consumption sensing mechanism 9, and an underwater visual pollution monitoring mechanism 10.

[0036] The replaceable outer shell mechanism 5 includes an inner waterproof sealing shell 51, an outer replaceable protective shell 52, and a detachable connection structure 53. The inner waterproof sealing shell 51 is disposed outside the main body 1 of the device, and the outer replaceable protective shell 52 is assembled to the outside of the inner waterproof sealing shell 51 through the detachable connection structure 53. The outer replaceable protective shell 52 is made of a bio-attachment inhibitory material. The ultraviolet active irradiation anti-bioattachment mechanism 6 includes an optical window 61, an ultraviolet LED array 62, an ultraviolet driving circuit 63, and an irradiation timing controller 64. The optical window 61 is located at the optical measurement front end of the main body 1 of the device. The ultraviolet LED array 62 is arranged around the optical window 61. The ultraviolet driving circuit 63 is electrically connected to the ultraviolet LED array 62. The irradiation timing controller 64 is connected to the optical measurement unit 2 and the ultraviolet driving circuit 63 respectively. The irradiation timing controller 64 turns on ultraviolet irradiation during non-measurement periods and turns off ultraviolet irradiation during measurement periods. The ultraviolet driving circuit 63 and the irradiation timing controller 64 are both integrated inside the control unit 3. The ultraviolet water circulation liquid cooling heat dissipation mechanism 7 includes a heat sink module 71, a circulating water pump 72, a liquid cooling pipeline 73, and external heat dissipation fins 74. The heat sink module 71 is attached to the back of the ultraviolet LED array 62 to conduct the heat generated by the ultraviolet LED array 62 during operation. The circulating water pump 72 is connected to the heat sink module 71 through the liquid cooling pipeline 73 to provide power for the circulation of coolant. The liquid cooling pipeline 73 connects the heat sink module 71 and the external heat dissipation fins 74 to form a closed heat exchange loop. The external heat dissipation fins 74 receive the heat carried by the coolant through the liquid cooling pipeline 73 and dissipate the heat into the external water body, indirectly cooling the ultraviolet LED array 62. The heat sink module 71, the circulating water pump 72, the liquid cooling pipeline 73, and the external heat dissipation fins 74 form a closed water circulation cooling loop. The copper ion active release anti-bioattachment mechanism 8 includes a copper anode electrode 81, an auxiliary electrode 82, a constant current control circuit 83, and an ion release timing controller 84. The constant current control circuit 83 is electrically connected to both the copper anode electrode 81 and the auxiliary electrode 82. Both the copper anode electrode 81 and the auxiliary electrode 82 are located on the outside of the inner waterproof sealed shell 51, directly in contact with the water, and rely on low-pressure electrolysis to slowly release trace amounts of copper ions into the surrounding water to achieve bio-repellency. The ion release timing controller 84 is signal-connected to the constant current control circuit 83 to control the intermittent output of electrolysis current by the constant current control circuit 83. The ion release timing controller 84 is integrated inside the control unit 3. The electrode consumption sensing mechanism 9 includes a consumption sensing sensor 91 and an alarm communication module 92. The consumption sensing sensor 91 is embedded inside the copper anode electrode 81, and the alarm communication module 92 is integrated inside the control unit 3. The alarm communication module 92 is connected to the consumption sensing sensor 91 and the communication unit 4 respectively. When the copper anode electrode 81 is worn down to a preset threshold, an alarm is triggered. The consumption sensing sensor 91 and the alarm communication module together form the electrode consumption sensing mechanism 9. The underwater visual pollution monitoring device 10 includes a miniature camera 101, a timed image capture control module 102, and an image intelligent analysis module 103. The miniature camera 101 is installed inside the main body 1 of the device. The timed image capture control module 102 and the image intelligent analysis module 103 are both integrated inside the control unit 3. The timed image capture control module 102 is connected to the miniature camera 101 by signal. The image intelligent analysis module 103 is connected to the timed image capture control module 102 and the communication unit 4 by signal. The miniature camera 101 periodically captures images of the optical window 61. The timed image capture control module 102 and the image intelligent analysis module 103 identify the degree of pollution. If the pollution exceeds the standard, an intelligent alarm is triggered.

[0037] In detail, the outer replaceable protective shell 52 is made of a transparent polymer material with nanoscale surface microstructures. The surface micro-nano structure reduces the contact area for microbial attachment, and the entire shell can be disassembled and replaced individually to reduce underwater maintenance costs.

[0038] The optical window 61 is made of sapphire glass or quartz glass; the ultraviolet LED array 62 uses ultraviolet LEDs with a wavelength of 200-280nm in the UV-C band, and multiple LEDs are evenly arranged around the optical window 61.

[0039] The heat sink module 71 is made of a metal material with high thermal conductivity and has a serpentine liquid cooling channel inside. The coolant circulates in a closed loop formed by the heat sink module 71, the circulating water pump 72, the liquid cooling pipe 73 and the external heat dissipation fins 74. After the coolant flows through the heat sink module 71 to absorb the working heat of the ultraviolet LED array 62, it conducts the heat to the external water body through the external heat dissipation fins 74 to avoid premature decay of the LED at high temperature.

[0040] The copper anode electrode 81 is made of electrolytic copper with a purity of ≥99.9%; the auxiliary electrode 82 is a carbon electrode; and the constant current control circuit 83 outputs an adjustable constant current within the range of 1 to 10 mA.

[0041] The consumption sensor 91 is a resistive sensing element and is embedded in the copper anode electrode 81 at a preset depth. When electrolysis causes the copper anode electrode 81 to wear down to the preset depth, the sensor circuit resistance of the consumption sensor 91 changes abruptly, and an alarm signal is output to the alarm communication module 92.

[0042] Control unit 3 controls each subsystem to operate in a coordinated manner according to a preset timing sequence; the measurement timing sequence and the ultraviolet irradiation timing sequence are carried out alternately, and the copper ion electrolytic discharge and the image acquisition of the miniature camera 101 are both executed according to a preset cycle. When the ultraviolet LED array 62 is working, the water circulation liquid cooling heat dissipation device is started synchronously. After the ultraviolet light is turned off, the water pump stops after a delay to remove the residual heat.

[0043] The image intelligent analysis module 103 uses a deep learning-based dirt recognition model to analyze the dirt level of the image of the optical window 61 captured by the miniature camera 101, calculates the ratio of the area of ​​the light-transmitting region to the total area of ​​the optical window 61, and triggers an alarm when the ratio is lower than a preset threshold.

[0044] Communication unit 4 supports wired and wireless dual-mode communication; communication unit 4 uploads real-time sand content measurement data, consumption status of copper anode electrode 81, degree of contamination of optical window 61 and fault information of each subsystem to the remote monitoring platform.

[0045] The inner waterproof sealing shell 51 is made of 316L stainless steel. An O-ring 511 is provided at the connection between the inner waterproof sealing shell 51 and the main body 1 of the device. A positioning boss 512 is provided on the side of the inner waterproof sealing shell 51 facing the outer replaceable protective shell 52. A positioning groove 521 is provided on the side of the outer replaceable protective shell 52 corresponding to the positioning boss 512. A light-transmitting hole 522 is provided on the outer replaceable protective shell 52 corresponding to the position of the optical window 61. An annular sealing groove 523 is provided around the light-transmitting hole 522. The detachable connection structure 53 adopts a snap-fit ​​assembly structure, which facilitates quick underwater disassembly and replacement of the outer replaceable protective shell 52.

[0046] A miniature camera 101 is installed inside the main body 1 of the device and faces the inner surface of the optical window 61. The miniature camera 101 uses a CMOS image sensor with a resolution of no less than 1920×1080 pixels and is equipped with a near-infrared LED, enabling it to capture clear images even in the absence of external light. The timed image capture control module 102 is set to capture one image every 24 hours, and the images are processed by the image intelligent analysis module 103. The image intelligent analysis module 103 deploys a dirt recognition model based on deep learning, which is pre-trained using a large number of images of the optical window 61 with different levels of dirt. The image intelligent analysis module 103 first preprocesses the images, including grayscale conversion, median filtering for noise reduction, and contrast enhancement. Then, it extracts the light-transmitting area of ​​the optical window 61 using an image segmentation algorithm, calculates the ratio of the area of ​​the light-transmitting area to the total area of ​​the optical window 61, and triggers an intelligent alarm when the ratio is lower than a preset threshold (e.g., 85%).

[0047] Control unit 3 employs a low-power ARM architecture embedded processor, running a real-time operating system to uniformly manage the timing of various functions of the device. For example... Figure 5 Control unit 3 executes the following timing control strategy: 1. Measurement cycle: Sand content measurement is performed every 30 minutes, and each measurement lasts for 30 seconds; 2. Ultraviolet Irradiation: Ultraviolet irradiation is continuously turned on during the non-measurement period between measurement cycles (i.e., approximately 29.5 minutes from the end of each measurement to the start of the next measurement); ultraviolet irradiation is automatically turned off during the measurement period to avoid interference with optical measurements; 3. Copper ion release: Perform a copper ion release operation once every 24 hours for 10 minutes, with the constant current set to 5mA. The release operation should be avoided during the measurement period. 4. Image acquisition: Take an image of the inner surface of optical window 61 once a day at a set time (e.g., 0:00 every day). Before taking the image, temporarily turn on the near-infrared supplementary light LED. 5. Liquid cooling system: When the ultraviolet LED array 62 is working, the circulating water pump 72 is turned on simultaneously. After the ultraviolet light is turned off, the system runs for 2 minutes to fully remove the residual heat, and then the circulating water pump 72 is turned off.

[0048] Communication unit 4 adopts a dual-mode design with a 4G / 5G wireless communication module and an RS-485 wired communication interface. In near-shore areas or areas with mobile communication signals, 4G / 5G wireless communication is prioritized for uploading measurement data and device status information to the remote monitoring platform. In remote areas without mobile communication signals, an RS-485 bus can be used to connect to the data acquisition unit, and data transmission can be achieved through BeiDou short message service or satellite communication. The communication content includes: sediment concentration measurement data, cumulative working time of ultraviolet LEDs, consumption status of copper anode electrode 81, turbidity score of optical window 61, internal temperature and humidity of the device, and operating status of each subsystem.

[0049] The replaceable outer protective shell 52 is made of a transparent polymer material with a nanoscale surface structure (such as polycarbonate with a nanoimprinted surface). The nanopore structure reduces the surface area for microbial adhesion; the nanopore diameter is approximately 50–200 nm, and the depth is 100–300 nm. This material is optically transparent, with a transmittance of no less than 85% in the visible light band. When using this material, there is no need to create a light-transmitting hole 522 at the position corresponding to the optical window 61 in the replaceable outer protective shell 52; the entire replaceable outer protective shell 52 is transparent, simplifying the sealing structure design. Furthermore, because the material itself has physical properties that inhibit bioattachment, there is no need to add chemical anti-bioattachment agents, making it more environmentally friendly.

[0050] The copper ion active release anti-bioattachment system employs a dual-electrode pair design, with a pair of copper anode electrodes 81 and an auxiliary electrode 82 respectively positioned on both sides of the device housing. These two pairs of electrodes work alternately, further extending the single maintenance cycle. Simultaneously, the consumption sensing sensor 91 utilizes an online monitoring method based on electrochemical impedance spectroscopy (EIS). By measuring the change in the AC impedance spectrum between the copper anode electrode 81 and the auxiliary electrode 82, it assesses the remaining thickness of the copper anode electrode 81 in real time, achieving more accurate monitoring of its consumption status.

[0051] The miniature camera 101 of the underwater visual fouling monitoring device 10 can also be installed on the outside of the main body 1 of the device, and take pictures facing the outer surface of the optical window 61 through an independent waterproof sealed window to directly monitor the fouling and deposits on the outer surface of the optical window 61. This solution can more directly assess the degree of external biofouling, but it requires anti-biofouling measures for the miniature camera 101 itself, which can be achieved by setting a miniature ultraviolet LED at its window for local anti-biofouling protection.

[0052] Solution Analysis: 1. This innovative solution integrates a passive and active dual anti-biofouling system, adapting to complex water body observation scenarios with high sediment content, and completely solving the shortcomings of traditional equipment's single anti-fouling methods, poor effectiveness, and environmental pollution. The replaceable outer shell mechanism 5 serves as the basic passive protection structure. The inner waterproof sealing shell 51, combined with O-rings 511, achieves deep-water sealing protection for the entire machine. Precise alignment and assembly are achieved through the positioning boss 512 and the positioning groove 521 of the outer replaceable protective shell 52. A snap-fit ​​detachable connection structure 53 enables rapid underwater disassembly and replacement, significantly reducing the difficulty and cost of underwater equipment maintenance. The outer replaceable protective shell 52 uses a transparent polymer material with a nano-surface microstructure, which can significantly reduce the contact area between sediment particles and aquatic microorganisms at the physical level, eliminating the need for toxic chemical antifouling agents. It balances anti-fouling effectiveness with the ecological safety of the aquatic environment, while also preventing sediment deposition and the formation of a biofilm substrate, thus adapting to the harsh observation conditions of high-sediment-content water bodies from the source.

[0053] 2. The active ultraviolet irradiation anti-biofouling mechanism 6 achieves precise and interference-free active sterilization and anti-fouling of the optical window 61, effectively ensuring the accuracy of sand content observation. The sapphire or quartz optical window 61 has good light transmittance and is wear- and corrosion-resistant, providing a basic guarantee for high-precision optical measurement. The surrounding UV-C band ultraviolet LED array 62 can fully cover the surface of the optical window 61, effectively killing attached microorganisms and inhibiting biofilm growth. Relying on the linkage timing logic between the irradiation timing controller 64 and the optical measurement unit 2, the ultraviolet driving circuit 63 and the ultraviolet LED array 62 are strictly turned off during the measurement period, and the ultraviolet anti-fouling is turned on during non-measurement periods, completely avoiding the interference of ultraviolet light on the optical sand measurement signal, perfectly solving the technical problem that traditional ultraviolet anti-fouling equipment cannot balance anti-fouling effect and measurement accuracy.

[0054] 3. The equipped UV water circulation liquid cooling heat dissipation mechanism 7 completely solves the problems of high temperature premature aging, high energy consumption, and poor stability of UV LEDs during long-term operation, significantly extending the service life of the equipment. The heat sink module 71, made of high thermal conductivity metal and with a built-in serpentine flow channel, can efficiently absorb the working heat of the UV LED array 62. The circulating water pump 72 provides stable circulation power for the coolant inside the liquid cooling pipeline 73. Together with the external heat dissipation fins 74, a closed water circulation heat exchange loop is formed, which can quickly transfer the working heat of the LED to the external water body for heat dissipation. At the same time, the equipment has a delayed heat dissipation logic. After the UV LED array 62 is shut down, the circulating water pump 72 stops after a 2-minute delay, which fully removes the residual heat, effectively avoiding high temperature aging and light decay failure of the LED, ensuring the long-term stable operation of the UV anti-attachment system, and reducing the frequency of equipment replacement and long-term operation and maintenance costs.

[0055] 4. The copper ion active release anti-bioattachment mechanism 8 achieves long-lasting, intermittent, and environmentally friendly biological repellency in water bodies, overcoming the limitation of single ultraviolet sterilization in removing stubborn attached organisms. A copper anode electrode 81 with a purity ≥99.9% paired with a carbon auxiliary electrode 82 can electrolyze water at low pressure under the adjustable constant current of 10mA controlled by a constant current control circuit 831, slowly releasing trace amounts of copper ions to achieve wide-range, long-lasting biological repellency. The ion release timing controller 84 precisely controls the electrolysis sequence, operating for short periods daily and completely avoiding optical measurement periods, ensuring continuous algae suppression and anti-attachment effects without interfering with sediment content measurement data. Simultaneously, the dual-sided dual-electrode pair alternating working mode effectively extends the electrode's single-use cycle, further reducing equipment maintenance frequency.

[0056] 5. The electrode consumption sensing mechanism 9 enables intelligent monitoring and early warning of electrode consumption, eliminating the problem of unnoticed failure of the equipment's anti-fouling function. The consumption sensing sensor 91, embedded inside the copper anode electrode 81, can accurately monitor the degree of electrode consumption in real time through resistance change or electrochemical impedance spectroscopy. When the electrode consumption reaches a preset safety threshold, an early warning signal is immediately generated through the alarm communication module 92, and the communication unit 4 is linked to upload the early warning information. This allows staff to inspect and replace the electrode in advance, ensuring the continuous and stable operation of the copper ion anti-fouling system and avoiding equipment biofouling failures caused by electrode consumption.

[0057] 6. The underwater visual fouling monitoring mechanism 10 achieves intelligent autonomous detection of the fouling status of the optical window 61, eliminating the need for traditional manual inspection. A high-resolution miniature camera 101 equipped with near-infrared supplemental lighting can clearly capture images of the inner and outer surfaces of the optical window 61 in all-weather, light-free environments. The timed image capture control module 102 enables automated timed image acquisition without manual intervention. The intelligent image analysis module 103, relying on a deep learning model, calculates the light-transmitting area ratio of the optical window 61 through image preprocessing and segmentation, using an 85% transmittance threshold for precise judgment. This enables quantitative identification of the degree of fouling and automatic alarm for exceeding limits, accurately controlling the equipment's observation conditions and ensuring the continuity and accuracy of measurement data.

[0058] 7. The low-power ARM architecture control unit 3 serves as the core, coordinating the timing and operation of the entire system to achieve intelligent time-sharing linkage among various subsystems, resulting in a high degree of automation and intelligence. The control unit 3, through preset precise timing strategies, systematically manages all functional modules, including optical measurement, UV protection, copper ion release, image acquisition, and liquid cooling. Each system performs its function independently without interference, ensuring full coverage of all protective functions while completely avoiding interference from auxiliary systems to the core sediment content measurement. Simultaneously, the low-power operation mode effectively reduces the energy consumption of the equipment during long-term underwater operations.

[0059] 8. The dual-mode communication unit 4 ensures stable data transmission and adaptability to various hydrological monitoring environments. The device supports 4G / 5G wireless and RS-485 wired dual-mode communication, adapting to near-shore signal coverage areas and remote, signal-free waters. It is compatible with BeiDou satellite-assisted transmission and can remotely upload real-time data on sediment concentration measurement, electrode wear status, window turbidity, equipment faults, and operating parameters of each subsystem. This enables remote monitoring and unattended operation, significantly improving the efficiency of hydrological monitoring.

[0060] Working principle: During operation, the control unit 3 acts as the core control center, coordinating the timing and collaborative operation of all modules. Passive biofouling protection is achieved through the replaceable outer shell mechanism 5. Its inner waterproof sealing shell 51 uses O-rings 511 for overall sealing. Precise assembly is achieved via positioning bosses 512 and positioning grooves 521 of the outer replaceable protective shell 52, with quick assembly and disassembly via snap-fit ​​detachable connection structure 53. The outer replaceable protective shell 52, with its nano-surface microstructure, physically reduces the contact area between aquatic microorganisms and sediment, achieving passive biofouling protection without chemical pollution. Every 30 minutes, the device performs a 30-second optical detection of water sediment content via the optical measurement unit 2. During the detection, the irradiation timing controller 64 simultaneously shuts down the ultraviolet drive circuit 63 and the ultraviolet LED array 62 to prevent UV-C band light from interfering with the optical measurement accuracy. The ultraviolet LED array 62 is activated only during non-measurement periods to continuously irradiate the optical window 61, achieving active sterilization and anti-fouling of the optical window 61 surface. During the operation of the ultraviolet LED array 62, the high thermal conductivity metal heat sink module 71 attached to its back conducts working heat through the internal serpentine liquid cooling channel. The circulating water pump 72 provides circulation power for the coolant in the liquid cooling pipe 73, so that the coolant continuously exchanges heat in the closed loop formed by the heat sink module 71, the liquid cooling pipe 73 and the external heat dissipation fins 74. The heat is dissipated into the external water body through the external heat dissipation fins 74. After the ultraviolet LED array 62 stops working, the circulating water pump 72 stops after a 2-minute delay to completely remove the residual heat of the equipment and prevent premature aging of the LEDs due to high temperature. At the same time, the ion release timing controller 84 controls the constant current control circuit 83 to work intermittently with a constant current of 5mA, driving a purity ≥99% every 24 hours, avoiding the measurement period.A 9% copper anode electrode 81 and a carbon auxiliary electrode 82 electrolyze water at low pressure, slowly releasing trace amounts of copper ions to achieve long-term biological repellency in the water. The device employs a dual-sided, dual-electrode alternating operating mode to extend maintenance cycles. A resistive wear sensor 91 embedded within the copper anode electrode 81 monitors electrode wear in real time via resistance changes or electrochemical impedance spectroscopy. When electrode wear reaches a preset threshold, a remote alarm is immediately triggered via the alarm communication module 92 and communication unit 4. Throughout the device's operation, a timed photo capture control module 102 triggers a 1080P CMOS miniature camera 101 equipped with near-infrared supplemental lighting daily to capture images. Images are acquired from the inner and outer surfaces of the optical window 61. After preprocessing (including grayscale conversion, noise reduction, and contrast enhancement) and image segmentation by the image intelligent analysis module 103, the proportion of the light-transmitting area to the total area of ​​the optical window 61 is calculated. When this proportion falls below a preset threshold of 85%, a pollution exceeding the standard alarm is triggered. Finally, the communication unit 4, supporting dual-mode communication of 4G / 5G wireless and RS-485 wired communication, can upload real-time data on sediment concentration measurement, the consumption status of the copper anode electrode 81, the degree of pollution of the optical window 61, and operational fault information of each subsystem to a remote platform. This enables long-term, high-precision, and low-maintenance intelligent optical observation operations in high-sediment-content water environments.

[0061] Technical effects of implementing this solution: This solution overcomes many technical bottlenecks of traditional optical sediment concentration observation devices, such as single anti-fouling methods, susceptibility to interference from sediment and biofouling, unstable measurement accuracy, cumbersome operation and maintenance, and high energy consumption. It constructs a comprehensive technical solution integrating passive physical protection, active ultraviolet sterilization, long-term copper ion repellency, intelligent status monitoring, precise timing control, and efficient heat dissipation protection. It is specifically adapted to the long-term underwater monitoring conditions of complex water bodies with high sediment concentration, effectively improving the accuracy, continuity, and stability of sediment concentration observation data, significantly reducing underwater operation and maintenance costs and the frequency of manual intervention, and is energy-saving, environmentally friendly, highly adaptable, and highly automated and intelligent. It has extremely high practical application value and promotion prospects in hydrological engineering.

[0062] The present invention comprises: 1-Main body of the device; 2-Optical measurement unit; 3-Control unit; 4-Communication unit; 5-Replaceable outer shell mechanism; 51-Inner waterproof sealing shell; 511-O-ring seal; 512-Positioning boss; 52-Outer replaceable protective shell; 521-Positioning groove; 522-Light transmission hole; 523-Annular sealing groove; 53-Detachable connection structure; 6-Ultraviolet active irradiation anti-bioattachment mechanism; 61-Optical window; 62-Ultraviolet LED array; 63-Ultraviolet driving circuit; 64-Irradiation timing controller; 7-Ultraviolet water circulation liquid cooling heat dissipation mechanism; 71-Heat sink module; 72-Circulating water pump; 73-Liquid cooling pipeline; 74-External heat dissipation fins; 8-Copper ion active release anti-bioattachment mechanism; 81-Copper anode electrode; 82-Auxiliary electrode; 83-Constant current control circuit; 84-Ion release... The components include: a timing controller; an electrode consumption sensing mechanism; a consumption sensing sensor; an alarm communication module; an underwater visual pollution monitoring mechanism; a miniature camera; a timed photo control module; and an image intelligent analysis module. These components are all general-purpose standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods. The problem this invention solves is that existing methods for preventing biofouling on underwater optical windows are all flawed and only provide single-mode protection. There is a lack of integrated anti-fouling solutions that are suitable for measuring sediment content in high-sediment-content water bodies, integrating passive protection, active protection, and intelligent monitoring. Furthermore, high sediment deposition accelerates biofouling, and sediment content measurement places stringent requirements on the transmittance of optical windows; existing solutions cannot meet the needs of these special operating conditions. This invention constructs an integrated system of multi-layered protection, intelligent monitoring, and timed heat dissipation, solving multiple defects of traditional sediment measurement devices. It is suitable for long-term underwater monitoring of high-sediment-content water bodies, and combines the advantages of high precision, low maintenance, energy saving, environmental protection, and high intelligence, making it highly valuable for engineering promotion.

[0063] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0064] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An optical observation device for sand content that integrates active and passive anti-bioattachment mechanisms, characterized in that: The device includes a main body (1), which contains an optical measurement unit (2), a control unit (3), a communication unit (4), a replaceable outer shell mechanism (5), an ultraviolet active irradiation anti-bioattachment mechanism (6), an ultraviolet water circulation liquid cooling heat dissipation mechanism (7), a copper ion active release anti-bioattachment mechanism (8), an electrode consumption sensing mechanism (9), and an underwater visual pollution monitoring mechanism (10). The replaceable outer shell mechanism (5) includes an inner waterproof sealing shell (51), an outer replaceable protective shell (52), and a detachable connection structure (53). The inner waterproof sealing shell (51) is disposed outside the main body (1) of the device. The outer replaceable protective shell (52) is assembled to the outside of the inner waterproof sealing shell (51) through the detachable connection structure (53). The outer replaceable protective shell (52) is made of a bio-attachment inhibitory material. The ultraviolet active irradiation anti-bioattachment mechanism (6) includes an optical window (61), an ultraviolet LED array (62), an ultraviolet driving circuit (63), and an irradiation timing controller (64). The optical window (61) is located at the optical measurement front end of the main body (1) of the device. The ultraviolet LED array (62) is arranged around the optical window (61). The ultraviolet driving circuit (63) is electrically connected to the ultraviolet LED array (62). The irradiation timing controller (64) is signal connected to the optical measurement unit (2) and the ultraviolet driving circuit (63) respectively. The irradiation timing controller (64) turns on ultraviolet irradiation during non-measurement periods and turns off ultraviolet irradiation during measurement periods. The ultraviolet driving circuit (63) and the irradiation timing controller (64) are both integrated inside the control unit (3). The ultraviolet water circulation liquid cooling heat dissipation mechanism (7) includes a heat sink module (71), a circulating water pump (72), a liquid cooling pipeline (73), and external heat dissipation fins (74). The heat sink module (71) is attached to the back of the ultraviolet LED array (62) to conduct heat generated by the ultraviolet LED array (62) during operation. The circulating water pump (72) is connected to the heat sink module (71) through the liquid cooling pipeline (73) to provide power for the circulation of coolant. The liquid cooling pipeline (73) connects the heat sink module (71) and the external heat dissipation fins (74) to form a closed heat exchange circuit. The external heat dissipation fins (74) receive the heat carried by the coolant through the liquid cooling pipeline (73) and dissipate the heat into the external water body, indirectly cooling the ultraviolet LED array (62). The heat sink module (71), the circulating water pump (72), the liquid cooling pipeline (73), and the external heat dissipation fins (74) form a closed water circulation cooling circuit. The copper ion active release anti-bioattachment mechanism (8) includes a copper anode electrode (81), an auxiliary electrode (82), a constant current control circuit (83), and an ion release timing controller (84). The constant current control circuit (83) is electrically connected to the copper anode electrode (81) and the auxiliary electrode (82) respectively. The copper anode electrode (81) and the auxiliary electrode (82) are both arranged on the outside of the inner waterproof sealing shell (51) and directly contact the water body. They rely on low-pressure electrolysis to slowly release trace amounts of copper ions to the surrounding water body to achieve bio-repellency. The ion release timing controller (84) is signal-connected to the constant current control circuit (83) to control the constant current control circuit (13) to intermittently output electrolysis current. The ion release timing controller (84) is integrated inside the control unit (3). The electrode consumption sensing mechanism (9) includes a consumption sensing sensor (91) and an alarm communication module (92). The consumption sensing sensor (91) is embedded inside the copper anode electrode (81), and the alarm communication module (92) is integrated inside the control unit (3). The alarm communication module (92) is connected to the consumption sensing sensor (91) and the communication unit (4) respectively. When the copper anode electrode (81) is worn down to a preset threshold, an alarm is triggered. The consumption sensing sensor (91) and the alarm communication module together constitute the electrode consumption sensing mechanism (9). The underwater visual pollution monitoring mechanism (10) includes a miniature camera (101), a timed photo control module (102), and an image intelligent analysis module (103). The miniature camera (101) is located inside the main body (1) of the device. The timed photo control module (102) and the image intelligent analysis module (103) are both integrated inside the control unit (3). The timed photo control module (102) is connected to the miniature camera (101) by signal. The image intelligent analysis module (103) is connected to the timed photo control module (102) and the communication unit (4) by signal. The miniature camera (101) periodically collects images of the optical window (61). The timed photo control module (102) and the image intelligent analysis module (103) identify the degree of pollution. If the pollution exceeds the standard, an intelligent alarm is triggered.

2. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 1, characterized in that: The outer replaceable protective shell (52) is made of a transparent polymer material with nano-surface microstructure. The surface micro-nano structure reduces the contact area for microbial attachment. The shell can be disassembled and replaced individually to reduce underwater maintenance costs.

3. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 2, characterized in that: The optical window (61) is made of sapphire glass or quartz glass; the ultraviolet LED array (62) uses ultraviolet LEDs with a wavelength of 200-280nm in the UV-C band, and multiple LEDs are evenly arranged around the optical window (61).

4. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 3, characterized in that: The heat sink module (71) is made of a metal material with high thermal conductivity and has a serpentine liquid cooling channel inside. The coolant circulates in a closed loop formed by the heat sink module (71), the circulating water pump (72), the liquid cooling pipeline (73) and the external heat dissipation fins (74). After the coolant flows through the heat sink module (71) to absorb the working heat of the ultraviolet LED array (62), it conducts the heat to the external water body through the external heat dissipation fins (74) to avoid premature decay of the LED at high temperature.

5. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 4, characterized in that: The copper anode electrode (81) is made of electrolytic copper with a purity of ≥99.9%; the auxiliary electrode (82) is a carbon electrode; and the constant current control circuit (83) outputs an adjustable constant current in the range of 1 to 10 mA.

6. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 5, characterized in that: The consumption sensor (91) is a resistive sensing element and is embedded in the copper anode electrode (81) at a preset depth. When electrolysis causes the copper anode electrode (81) to wear down to the preset depth, the sensor circuit resistance of the consumption sensor (91) changes abruptly, and an alarm signal is output to the alarm communication module (92).

7. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 6, characterized in that: The control unit (3) controls each subsystem to operate in a coordinated manner according to a preset time sequence; the measurement time sequence and the ultraviolet irradiation time sequence are carried out alternately, the copper ion electrolytic discharge and the image acquisition of the miniature camera (101) are both executed according to a preset cycle, the water circulation liquid cooling heat dissipation device is started synchronously when the ultraviolet LED array (62) is working, and the water pump is delayed and stopped after the ultraviolet light is turned off to remove the residual heat.

8. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 7, characterized in that: The image intelligent analysis module (103) uses a deep learning-based dirt recognition model to analyze the dirt level of the image of the optical window (61) captured by the miniature camera (101), calculates the ratio of the area of ​​the light-transmitting region to the total area of ​​the optical window (61), and triggers an alarm when the ratio is lower than a preset threshold.

9. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 8, characterized in that: The communication unit (4) supports wired and wireless dual-mode communication; the communication unit (4) uploads real-time sand content measurement data, the consumption status of the copper anode electrode (81), the degree of contamination of the optical window (61) and the operation fault information of each subsystem to the remote monitoring platform.

10. The optical observation device for sand content that integrates active and passive anti-bioattachment as described in claim 9, characterized in that: The inner waterproof sealing shell (51) is made of 316L stainless steel. An O-ring (511) is provided at the connection between the inner waterproof sealing shell (51) and the main body (1) of the device. A positioning boss (512) is provided on the side of the inner waterproof sealing shell (51) facing the outer replaceable protective shell (52). A positioning groove (521) is provided on the side of the outer replaceable protective shell (52) corresponding to the positioning boss (512). A light-transmitting hole (522) is provided on the outer replaceable protective shell (52) corresponding to the position of the optical window (61). An annular sealing groove (523) is provided around the light-transmitting hole (522). The detachable connection structure (53) adopts a snap-fit ​​assembly structure, which facilitates quick underwater disassembly and replacement of the outer replaceable protective shell (52).

Images