Acoustic-based monitoring method for seabed mining plume redeposition thickness monitoring device

Abstract

The present invention provides a monitoring method for a seabed mining plume redeposition thickness monitoring device based on acoustics. The device uses a high-precision redeposition thickness measuring instrument based on acoustics to monitor the redeposition thickness of plume particles, and uses the lifting and rotating functions of a multifunctional cantilever to self-clean the sediment collection box. Through the technical solution of the present invention, the monitoring efficiency and accuracy of the redeposition thickness of seabed mining plumes are significantly improved, the key problems in the prior art are solved, and reliable data support is provided for environmental protection and operation optimization of seabed mining.

Description

Technical Field

[0001] The present invention relates to the technical field of seabed mining monitoring, and in particular to a monitoring method of a seabed mining plume redeposition thickness monitoring device based on acoustics. Background Art

[0002] With the development of deep-sea mining, the impact of mining activities on the marine environment has received widespread attention. Among them, the plume phenomenon is a key environmental impact parameter in deep-sea mining activities. Plume is a particle diffusion phenomenon formed when sediment particles are disturbed into the water body during the mining process. These diffused particles will settle on the seabed to form redeposition after a certain period of diffusion and migration. The redeposition of plumes may have irreversible effects on organisms, which will cause serious damage to the seabed ecological environment.

[0003] At present, the monitoring and analysis of deep-sea re-deposition thickness mainly relies on remote-controlled unmanned submarine (ROV) binocular vision camera ranging technology (such as CN202410184528.2) and laboratory analysis. The ROV ranging system is equipped with a binocular ranging camera and a laser rangefinder. After taking pictures of the seabed, the thickness of the sediment is determined by image analysis. The specific location is usually determined by GPS or sonar to ensure the accuracy of the measurement. On the other hand, samples are obtained from the seabed through ROV or other sampling equipment, and then analyzed in the laboratory to determine the physical and chemical properties of the sediment.

[0004] However, existing technologies have limitations in many aspects. First, due to the complexity of the seabed environment, such as insufficient light and interference from water flow, the quality of the video will be affected, further limiting the accuracy of ROV image data analysis. Secondly, laboratory analysis methods have high requirements for sample integrity and are time-consuming, and cannot reflect the redeposition of plumes in real time, which has an impact on environmental protection work. In addition, the sampling process may affect the seabed environment, causing distortion of the final results. Finally, this method requires high operating skills and experience for ROVs, and consumes a lot of manpower and material resources. Therefore, the existing technology has some problems in terms of accuracy, timeliness, environmental impact, and difficulty of operation, and new technologies are urgently needed to improve the monitoring effect of the redeposition phenomenon of seabed mining plumes.

[0005] The plume phenomenon is a key environmental impact parameter in deep-sea mining activities. The redeposition of plumes may have irreversible effects on organisms and cause serious damage to the seabed ecological environment.

[0006] The current plume redeposition thickness monitoring technology is mostly carried out through ROV camera ranging and seabed sampling and laboratory analysis. Although these methods can provide relatively accurate data, they require a lot of time and manpower, and it is difficult to achieve real-time monitoring. In addition, the amount of samples processed by these methods is limited and may not fully reflect the actual situation. Therefore, the purpose of this patent is to provide a monitoring method for a seabed mining plume redeposition thickness monitoring device based on acoustics to solve the problems of high difficulty in real-time monitoring, low work efficiency, limited sample processing volume, and large measurement errors in the prior art. Summary of the invention

[0007] In order to make up for the deficiencies of the prior art, the present invention provides a monitoring method for a seabed mining plume redeposition thickness monitoring device based on acoustics, which is used for real-time monitoring and analysis of the redeposition thickness of plume particles generated during seabed mining.

[0008] The technical problems to be solved by this patent include:

[0009] Measuring plume redeposition thickness: Providing a device that can accurately measure plume redeposition thickness, ensuring high accuracy and reliability of the data.

[0010] Self-emptying collection box: The automatic emptying function is introduced to prevent the collection box from being full and unable to be used for secondary measurement, thereby improving the measurement accuracy and the use time of the equipment.

[0011] Real-time monitoring: Using an acoustic communication system, a device is provided that can monitor plume redeposition thickness in real time in a deep-sea environment, avoiding the time and manpower consumption caused by field sampling and indoor experiments.

[0012] Ensure data transmission stability: By designing a stable data transmission system, the reliability of data transmission in harsh marine environments is ensured.

[0013] Reduce equipment complexity and cost: adopt simple structure and low-cost device design to reduce equipment installation and maintenance costs and improve the promotion and application of technology.

[0014] The present invention is realized through the following technical scheme: a monitoring method of a seabed mining plume redeposition thickness monitoring device based on acoustics, the device comprising a high-precision redeposition thickness measuring instrument, a multifunctional cantilever, a sediment collection box, an acoustic communication unit, a battery compartment and a counterweight base, wherein the multifunctional cantilever comprises a cantilever cross bar, a cantilever rotating platform, a cantilever vertical bar and a cantilever connecting the collection box rotating shaft, the high-precision redeposition thickness measuring instrument is mounted on one end of the cantilever cross bar through a fixed clamp, the other end of the cantilever cross bar is fixedly mounted on the cantilever rotating platform, the cantilever rotating platform is mounted on the top of the cantilever vertical bar, the end of the cantilever vertical bar is fixedly mounted on the counterweight base, the cantilever vertical bar is a telescopic bar, the cantilever vertical bar is equipped with a cantilever connecting the collection box rotating shaft, one side of the cantilever connecting the collection box rotating shaft is connected to the sediment collection box, the sediment collection box is arranged below the high-precision redeposition thickness measuring instrument, the battery compartment is fixed on the counterweight base, and the acoustic communication unit is fixed on the battery compartment;

[0015] The specific steps include:

[0016] Step S1, default initial position: the cantilever vertical rod height is 15 cm, and the high-precision redeposition thickness measuring instrument is located outside the sediment collection box;

[0017] Step S2, start timed measurement: every 10 minutes, the cantilever rotating table starts to rotate the high-precision redeposition thickness measuring instrument to the top of the sediment collection box for 1 minute of measurement;

[0018] Step S3, data collection and analysis: the high-precision redeposition thickness measuring instrument transmits sound waves and receives reflected signals to calculate the redeposition thickness;

[0019] Step S4, real-time data transmission: the acoustic communication unit 5 transmits the measurement data to the ROV or other communication terminals;

[0020] Step S5, redeposition thickness detection: when the thickness measured by the high-precision redeposition thickness measuring instrument exceeds 5 cm, the cantilever vertical rod is raised to 30 cm;

[0021] Step S6, emptying the collection box: the cantilever is connected to the collection box rotation axis to rotate the sediment collection box 360 degrees to empty the sediment, and the cantilever vertical rod falls back to 15 cm;

[0022] Step S7, repeat the process: the high-precision redeposition thickness measuring instrument returns to the initial position, and continues the timed measurement and data collection;

[0023] Step S8, calculating the redeposition thickness using a high-precision redeposition thickness measuring instrument, specifically comprising the following steps:

[0024] Step S8-1, total propagation time calculation:

[0025] The propagation time of sound waves in the medium can be calculated by the integration method; assuming that the speed of sound 𝑣 is a function of the position 𝑥, the total time 𝑇 from the emission to the reception of the sound wave can be expressed as:

[0026]

[0027] Where: d w is the water depth; v w is the speed of sound waves in water; d s is the redeposition thickness; v s is the speed of sound waves in sediment;

[0028] Step S8-2, propagation time in water:

[0029] The travel time in water is 𝑡 𝑤 Calculated as:

[0030]

[0031] Step S8-3, propagation time in sediment:

[0032] The travel time in the sediment is 𝑡 s Calculated as:

[0033]

[0034] Step S8-4: Total propagation time and redeposition thickness

[0035] Combining the above formula, the total propagation time 𝑇 is:

[0036]

[0037] By rearranging the above formula, the redeposition thickness d can be solved 𝑠 :

[0038]

[0039] The total travel time 𝑇 and the known water depth d are measured by a high-precision redeposition thickness gauge 𝑤 and its speed of sound 𝑣 𝑤 , calculate the deposition thickness d 𝑠 .

[0040] As a preferred solution, the high-precision redeposition thickness measuring instrument includes an acoustic wave transmitter, an acoustic wave receiver, a signal processing unit and a data storage and transmission module.

[0041] As a preferred solution, the height of the cantilever vertical rod is 15cm-30cm.

[0042] As a preferred solution, the sediment collection box has a size of 30 cm long, 30 cm wide and 5 cm high.

[0043] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0044] 1. Re-deposition thickness measurement device and method

[0045] The existing camera ranging method is affected by factors such as light and camera angle, and the data error is large. This patent uses acoustic ranging technology to analyze the propagation and reflection characteristics of vertical sound waves to provide high-precision redeposition thickness data to ensure the accuracy and reliability of the monitoring results.

[0046] 2. Multifunctional lifting cantilever design

[0047] The patented multifunctional cantilever increases the flexibility of monitoring. The cantilever carrying the redeposition thickness gauge can be rotated to the outside during plume deposition, preventing the device itself from affecting particle deposition and ensuring the comprehensiveness and accuracy of the data.

[0048] 3. Self-cleaning collection box design

[0049] The existing collection box overflows when full, resulting in inaccurate measurement and the need for frequent cleaning. This patent has designed an automatic emptying function, which can empty the collected sediment particles by raising the cantilever and turning the collection box 360 degrees to prevent accumulation, improve the continuity and reliability of measurement, and reduce manual intervention and maintenance costs.

[0050] Additional aspects and advantages of the present invention will become apparent from the following description or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0052] Figure 1 It is a schematic diagram of the three-dimensional structure of the device of the present invention;

[0053] Figure 2 It is a schematic diagram of the main structure of the device of the present invention;

[0054] Figure 3 It is a schematic diagram of the top view of the structure of the device of the present invention;

[0055] Figure 4 It is a schematic diagram of the three-dimensional structure of the device of the present invention after vertical elevation;

[0056] Figure 5 It is a schematic diagram of the main structure of the device of the present invention after vertical elevation;

[0057] Figure 6 It is a schematic diagram of the structure of the device of the present invention when viewed from above after vertical elevation;

[0058] Figure 7 This is a graph showing the time variation of suspended particle deposition measured in the Bohai Bay using a sediment thickness measuring device.

[0059] in, Figures 1 to 6 The corresponding relationship between the reference numerals and the components is as follows:

[0060] 1: High-precision re-deposition thickness measuring instrument, 2: Fixed clamp, 3-1: Multi-function cantilever crossbar, 3-2: Multi-function cantilever rotating table, 3-3: Multi-function cantilever vertical rod, 4: Sediment collection box, 5: Acoustic communication unit, 6: Battery compartment, 7: Counterweight base DETAILED DESCRIPTION

[0061] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0062] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0063] Combine the following Figures 1 to 6 The monitoring method of the acoustic-based seabed mining plume redeposition thickness monitoring device according to an embodiment of the present invention is described in detail.

[0064] like Figures 1 to 6As shown, the present invention proposes a monitoring method for a seabed mining plume redeposition thickness monitoring device based on acoustics, which uses a high-precision redeposition thickness measuring instrument based on acoustics to monitor the redeposition thickness of plume particles, and uses the lifting and rotating functions of the multifunctional cantilever to clean the sediment collection box. The device includes a high-precision redeposition thickness measuring instrument 1, a multifunctional cantilever 3, a sediment collection box 4, an acoustic communication unit 5, a battery compartment 6 and a counterweight base 7, and the counterweight base 7 is used to fix the device without displacement. The high-precision redeposition thickness measuring instrument includes an acoustic wave transmitter, an acoustic wave receiver, a signal processing unit and a data storage and transmission module. The multifunctional cantilever 3 comprises a cantilever cross bar 3-1, a cantilever rotating platform 3-2, a cantilever vertical bar 3-3 and a cantilever connecting collection box rotating shaft (3-4, the high-precision redeposition thickness measuring instrument 1 is installed at one end of the cantilever cross bar 3-1 through a fixed clamp 2, the other end of the cantilever cross bar 3-1 is fixedly installed on the cantilever rotating platform 3-2, the cantilever rotating platform 3-2 is installed on the top of the cantilever vertical bar 3-3, the end of the cantilever vertical bar 3-3 is fixedly installed on the counterweight base 7, the cantilever vertical bar 3-3 is a telescopic rod, the height of the cantilever vertical bar 3-3 is 15cm-30cm, in special circumstances It can be raised to 30cm. During sediment deposition, the cantilever rotates the high-precision re-deposition thickness measuring instrument 1 to the top of the sediment collection box 4 for 1 minute every 10 minutes, and then rotates 90 degrees to retract and work in a cycle. When the re-deposition thickness data exceeds the 5cm collection box height, the cantilever vertical rod 3-3 is raised to 30cm, the cantilever connection collection box rotation axis 3-4 rotates 360 degrees to empty the sediment, and then the cantilever vertical rod 3-3 falls back to 15cm. The cantilever connection collection box rotation axis (3-4) is mounted on the cantilever vertical rod 3-3, and the cantilever connection collection box rotation axis (3-4) is on one side. Connect the sediment collection box 4, which is set below the high-precision redeposition thickness measuring instrument 1. The dimensions of the sediment collection box 4 are 30 cm long, 30 cm wide and 5 cm high. The collection box 4 is used to collect the redeposited sediments to ensure that the high-precision redeposition thickness measuring instrument 1 can accurately measure the redeposition thickness. Through the automatic rotation and lifting of the multifunctional cantilever 3, the collection box is emptied after the measurement to ensure the accuracy of continuous measurement. The battery compartment 6 is fixed on the counterweight base 7, and the acoustic communication unit 5 is fixed on the battery compartment 6; the acoustic communication unit 5 will transmit the high-precision redeposition thickness The redeposition thickness data collected by the high-precision redeposition thickness measuring instrument 1 is converted into an acoustic signal by an acoustic transmitter and sent to a nearby patrolling ROV or other communication terminal. The battery compartment provides power support for the entire device to ensure that the device can work stably for a long time in a deep-sea environment. The high-precision redeposition thickness measuring instrument 1 emits sound waves, which propagate in the water and encounter the sediment in the sediment collection box 4 and are reflected back to the receiver, which amplifies and transmits the signal. The signal processing unit calculates the sound wave propagation time and determines the redeposition thickness. The data storage and transmission module saves and transmits the measurement data to the acoustic communication unit 5.

[0065] The specific steps include:

[0066] Step S1, default initial position: the cantilever vertical rod 3-3 has a height of 15 cm, and the high-precision redeposition thickness measuring instrument 1 is located outside the sediment collection box 4;

[0067] Step S2, start timed measurement: every 10 minutes, the cantilever rotating platform 3-2 starts to rotate the high-precision redeposition thickness measuring instrument 1 to the top of the sediment collection box 4 for 1 minute of measurement;

[0068] Step S3, data collection and analysis: the high-precision redeposition thickness measuring instrument 1 transmits sound waves and receives reflected signals to calculate the redeposition thickness;

[0069] Step S4, real-time data transmission: the acoustic communication unit 5 transmits the measurement data to the ROV or other communication terminals;

[0070] Step S5, redeposition thickness detection: when the thickness measured by the high-precision redeposition thickness measuring instrument 1 exceeds 5 cm, the cantilever vertical rod 3-3 is raised to 30 cm;

[0071] Step S6, emptying the collection box: the cantilever is connected to the collection box rotating shaft 3-4 to rotate the sediment collection box 4360 degrees to empty the sediment, and the cantilever vertical rod 3-3 falls back to 15 cm;

[0072] Step S7, repeat the process: the high-precision redeposition thickness measuring instrument 1 returns to the initial position, and continues the timed measurement and data collection;

[0073] Step S8, calculating the redeposition thickness using the high-precision redeposition thickness measuring instrument 1, specifically comprising the following steps:

[0074] Step S8-1, total propagation time calculation:

[0075] The propagation time of the sound wave in the medium (water and sediment) can be calculated by the integration method; assuming that the speed of sound 𝑣 is a function of the position 𝑥, the total time 𝑇 from the emission to the reception of the sound wave can be expressed as:

[0076]

[0077] Where: d w is the water depth; v w is the speed of sound waves in water; d s is the redeposition thickness; v s is the speed of sound waves in sediment;

[0078] Step S8-2, propagation time in water:

[0079] The travel time in water is 𝑡 𝑤 Calculated as:

[0080]

[0081] Step S8-3, propagation time in sediment:

[0082] The travel time in the sediment is 𝑡 s Calculated as:

[0083]

[0084] Step S8-4: Total propagation time and redeposition thickness

[0085] Combining the above formula, the total propagation time 𝑇 is:

[0086]

[0087] By rearranging the above formula, the redeposition thickness d can be solved 𝑠 :

[0088]

[0089] The total travel time 𝑇 and the known water depth d are measured by a high-precision redeposition thickness gauge 𝑤 and its speed of sound 𝑣 𝑤 , the deposition thickness d can be accurately calculated 𝑠 .

[0090] like Figure 7 The figure shows the time variation of suspended particle deposition measured in Bohai Bay using a sediment thickness measuring device. It can be seen that the relative elevation of seafloor surface sediments at different stations changes under the action of water flow or other external forces. When the relative elevation increases, it means that suspended sediments are deposited at this station, and when the relative elevation decreases, it means that the surface sediments at this station may be eroded.

[0091] In the description of the present invention, the term "plurality" refers to two or more than two. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention; the terms "connection", "installation", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0092] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0093] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A monitoring method for a seabed mining plume redeposition thickness monitoring device based on acoustics, the device comprising a high-precision redeposition thickness measuring instrument (1), a multifunctional cantilever (3), a sediment collection box (4), an acoustic communication unit (5), a battery compartment (6) and a counterweight base (7), characterized in that The multifunctional cantilever (3) comprises a cantilever cross bar (3-1), a cantilever rotating platform (3-2), a cantilever vertical bar (3-3) and a cantilever connecting collection box rotating shaft (3-4). The high-precision redeposition thickness measuring instrument (1) is installed at one end of the cantilever cross bar (3-1) through a fixed clamp (2). The other end of the cantilever cross bar (3-1) is fixedly installed on the cantilever rotating platform (3-2). The cantilever rotating platform (3-2) is installed at the top of the cantilever vertical bar (3-3). The cantilever vertical bar (3-3) is connected to the cantilever vertical bar (3-4). -3) is fixedly mounted on a counterweight base (7), the cantilever vertical rod (3-3) is a retractable rod, a cantilever connecting collection box rotating shaft (3-4) is mounted on the cantilever vertical rod (3-3), one side of the cantilever connecting collection box rotating shaft (3-4) is connected to a sediment collection box (4), the sediment collection box (4) is arranged below the high-precision redeposition thickness measuring instrument (1), a battery compartment (6) is fixed on the counterweight base (7), and an acoustic communication unit (5) is fixed on the battery compartment (6); The specific steps include: Step S1, default initial position: the cantilever vertical rod (3-3) is 15 cm high, and the high-precision redeposition thickness measuring instrument (1) is located outside the sediment collection box (4); Step S2, start timed measurement: every 10 minutes, the cantilever rotating table (3-2) starts to rotate the high-precision redeposition thickness measuring instrument (1) to the top of the sediment collection box (4) to perform a 1-minute measurement; Step S3, data collection and analysis: the high-precision redeposition thickness measuring instrument (1) transmits sound waves and receives reflected signals to calculate the redeposition thickness; Step S4, real-time data transmission: the acoustic communication unit (5) transmits the measurement data to the ROV or other communication terminals; Step S5, redeposition thickness detection: when the thickness measured by the high-precision redeposition thickness measuring instrument (1) exceeds 5 cm, the cantilever vertical rod (3-3) is raised to 30 cm; Step S6, emptying the collection box: the cantilever is connected to the collection box rotation axis (3-4) to rotate the sediment collection box (4) 360 degrees to empty the sediment, and then the cantilever vertical rod (3-3) falls back to 15 cm; Step S7, repeat the process: the high-precision redeposition thickness measuring instrument (1) returns to the initial position, and continues the timed measurement and data collection; Step S8, calculating the redeposition thickness using a high-precision redeposition thickness measuring instrument (1), specifically comprising the following steps: Step S8-1, total propagation time calculation: The propagation time of sound waves in the medium can be calculated by the integration method; assuming that the speed of sound 𝑣 is a function of the position 𝑥, the total time 𝑇 from the emission to the reception of the sound wave can be expressed as: Where: d w is the water depth; v w is the speed of sound waves in water; d s is the redeposition thickness; v s is the speed of sound waves in sediment; Step S8-2, propagation time in water: The travel time in water is 𝑡 𝑤 Calculated as: Step S8-3, propagation time in sediment: The travel time in the sediment is 𝑡 s Calculated as: Step S8-4: Total propagation time and redeposition thickness Combining the above formula, the total propagation time 𝑇 is: By rearranging the above formula, the redeposition thickness d can be solved 𝑠 : The total travel time 𝑇 and the known water depth d are measured by a high-precision redeposition thickness gauge 𝑤 and its speed of sound 𝑣 𝑤 , calculate the deposition thickness d 𝑠 .

2. The method for monitoring the thickness of seabed mining plume redeposition based on acoustics according to claim 1, characterized in that The high-precision redeposition thickness measuring instrument includes an acoustic wave transmitter, an acoustic wave receiver, a signal processing unit and a data storage and transmission module.

3. The method for monitoring the thickness of seabed mining plume redeposition based on acoustics according to claim 1, characterized in that , the height of the cantilever vertical rod (3-3) is between 15cm and 30cm.

4. The monitoring method of the acoustic-based seabed mining plume redeposition thickness monitoring device according to claim 1 is characterized in that The dimensions of the sediment collection box (4) are 30 cm in length, 30 cm in width and 5 cm in height.

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