Device and method for low-disturbance sampling and pressure-maintaining sealing of submarine sediments

Abstract

The invention provides a device and a method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments, and relates to the technical field of deep-sea sediment collection, firstly, cutting disturbance to the sediments is greatly reduced through negative-pressure sampling; secondly, through pre-cleaning, the pressure maintaining success rate is remarkably increased; meanwhile, by additionally arranging a gas pressure maintaining structure, the deviation of system pressure and in-situ pressure after the sampling process is finished is reduced; in addition, rapid and efficient sealing of the sampling cylinder is realized through a simple clamping jaw type sealing mechanical structure; the device is simple in structure, sampling sequences can be increased or decreased according to requirements within the ROV carrying capacity range, single-time ROV diving multi-sequence sampling is achieved, the sampling efficiency is greatly improved, and important support can be provided for further scientific research of marine geology, microorganisms and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of deep-sea sediment collection, and more particularly to a device and method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments. Background Art

[0002] The deep sea floor, with its unique environmental conditions—high pressure, low temperature, and darkness—nourishes distinctive life systems and geological features. These factors not only contribute to the diversity of deep-sea ecology and geology, but also present significant challenges for scientific research. Studying deep-sea sediments and the microorganisms, minerals, and chemical components they contain is crucial for understanding the deep-sea carbon cycle, marine resource development, and the mechanisms of environmental change. However, due to the extreme and complex in situ environment of the deep sea, maintaining the pristine state of samples during collection, transportation, and subsequent research remains a pressing challenge.

[0003] Deep-sea sediments usually contain abundant dissolved gases (such as methane and carbon dioxide), which exist stably under high pressure and low temperature environments. Once exposed to low pressure and high temperature environments, the gas escape rate accelerates, resulting in significant changes in the gas content of sediment samples, thus affecting the accuracy of related research. In addition, the metabolic activities of deep-sea microorganisms are also affected by temperature and pressure. Drastic changes in the temperature and pressure environment may cause abnormal fluctuations in the metabolic rate of microorganisms, or even cause the death of microorganisms; this will have an adverse effect on the study of the in situ state of microbial ecosystems in sediments and related geochemical processes. Deep-sea sediments under high pressure and low temperature environments often exist in unique mineral and chemical states, such as gas hydrates or salt crystals, and these structures are very sensitive to changes in temperature and pressure. Under unsuitable environmental conditions, the physical structure of the sediments may collapse, and their mineralogical and chemical properties will also change significantly, which will affect the subsequent analysis results.

[0004] Currently, the most common problems in pressure sampling of seafloor sediments include:

[0005] 1) The collected sediment is easily detached from the sampling tube, resulting in a reduction in the sample quantity. To address this issue, several prior art patents propose reducing the probability of sample detachment by providing petals, sealed blades, and other structures at the bottom of the sampler (e.g., CN112985914B, CN212110626U, and CN118654928B). However, this approach cuts the sediment, significantly destroying its structure. Furthermore, for microbial research, this approach can also disrupt the axial layer sequence of the sediment, significantly affecting scientific test results.

[0006] 2) Sea mud adheres to or damages the sealing ring, resulting in failure of pressure maintenance. Sea mud adheres to the sealing ring or is damaged by sand, which is one of the most important reasons for the failure of pressure maintenance sampling. To solve the sealing probability problem, many patents adopt a double-barrel sampling method, in which the inner barrel is used for sampling and the outer barrel is used for pressure maintenance (such as CN112326343A, CN118583568A, CN114354243B). This method can basically prevent the problem of the sealing ring being damaged by sea mud, but it will also significantly increase the volume of the device and increase production costs.

[0007] 3) After the sample is taken and sealed, micro-leakage may cause the system pressure to deviate from the original pressure to a certain extent. Most existing pressure-maintaining sampling patents only consider the pressure-maintaining strength, but do not consider the possibility of micro-leakage in the device, which may cause the pressure in the device system to deviate from the original pressure. Since the compressibility of water is very small, once a micro-leakage occurs, the system pressure will drop rapidly.

[0008] 4) The pressure-maintaining structure is complex and usually requires an electronic control structure, which results in a larger system size. Adding a sampling sequence will significantly increase the cost. Summary of the Invention

[0009] In order to overcome the defects of the above-mentioned prior art in that the disturbance is large when collecting deep-sea sediments and it is difficult to achieve stable pressure-maintaining sealing, the present invention provides a device and method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments. The device greatly reduces the cutting disturbance of the sediment through negative pressure sampling; significantly improves the success rate of pressure maintenance through pre-cleaning; reduces the deviation of the system pressure and the in-situ pressure after the sampling process by adding a gas pressure-maintaining structure; and achieves fast and efficient sealing of the sampling tube through a simple mechanical structure. Due to the simple structure of the device, the sampling sequence can be increased or decreased according to demand within the carrying capacity of the ROV (Remote Operated Vehicle, underwater robot), realizing multi-sequence sampling in a single ROV dive, greatly improving the sampling efficiency. The device and method proposed in the present invention can provide important support for further scientific research on marine geology, microorganisms, etc.

[0010] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0011] A device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments, comprising: a sampling unit, a sealing unit, a cleaning unit, a pressure-maintaining unit, and a fixing frame; the sampling unit, sealing unit, cleaning unit, and pressure-maintaining unit are respectively mounted on the fixing frame;

[0012] The sampling unit is used for insertable negative pressure sampling of seabed sediments and includes: a handle, a first ball valve, and a sampling barrel; the lower end of the handle is connected to the upper end of the first ball valve, and the lower end of the first ball valve is connected to the upper end of the sampling barrel; the lower end of the handle is hollow and provided with a drain; the sampling barrel is a hollow cylindrical structure; the drain and the sampling barrel are connected through the first ball valve;

[0013] The sampling cylinder is detachably connected to the sealing unit. After the sampling unit completes sampling of seabed sediments, the sampling cylinder is connected to the sealing unit to achieve pressure-maintaining sealing of the sampling cylinder.

[0014] The sampling cylinder can be inserted into the cleaning unit for cleaning, thereby achieving pre-cleaning of the outer wall and the inner wall of the bottom end of the sampling cylinder;

[0015] The pressure-maintaining unit includes: a pressure-maintaining cylinder, a piston, an air injection valve and a connecting valve; the pressure-maintaining cylinder is a cylindrical structure with a hollow interior, the upper end of the pressure-maintaining cylinder is connected to the air injection valve, and the lower end is connected to one end of the connecting valve; the other end of the connecting valve is connected to the sealing unit; the piston is movably arranged inside the pressure-maintaining cylinder to isolate the seawater cavity and the air cavity inside the pressure-maintaining cylinder; the pressure-maintaining unit is used to carry the discharged seawater when the sealing unit seals the sampling cylinder, and after the sealing is completed, maintain the pressure inside the sampling unit to prevent micro-leakage.

[0016] Preferably, in the sampling unit, the handle is a T-shaped handle.

[0017] Preferably, the outer wall of the lower end of the sampling tube is provided with a plurality of grooves;

[0018] The sealing unit includes: an introduction groove, a sealing assembly and a second ball valve;

[0019] The introduction groove is arranged at the upper end of the sealing assembly, and the introduction groove is a tapered groove structure with an expanded opening facing upward;

[0020] The sealing assembly is a cylindrical structure as a whole, comprising: a plurality of sealing claws, the same number as the grooves, and a sealing platform and a sealing base; the sealing platform and the sealing base are connected; the lower end of the sealing base is connected to the upper end of the second ball valve; the plurality of sealing claws are respectively nested in the plurality of claw cavities of the sealing platform and are respectively telescopically connected to the sealing platform via claw springs; the contact surface between the sealing platform and the sealing base is equipped with a sealing ring;

[0021] The sampling cylinder is pluggably connected to the sealing platform. When the sampling cylinder is inserted into the sealing platform, a plurality of sealing claws are respectively embedded in the grooves on the outer wall of the lower end of the sampling cylinder to achieve claw-type sealing.

[0022] The lower end of the second ball valve is communicated with the connecting valve.

[0023] Preferably, the sealing platform and the sealing base are respectively provided with a first sealing groove and a second sealing groove for installing a sealing ring.

[0024] Preferably, the lower end of the handle is threadedly connected to the upper end of the first ball valve, and the lower end of the first ball valve is threadedly connected to the upper end of the sampling cylinder;

[0025] The sealing platform and the sealing base are threadedly connected; the lower end of the sealing base is threadedly connected to the upper end of the second ball valve.

[0026] Preferably, the cleaning unit is a cleaning tank with fluff provided inside. The sampling cylinder is inserted into the cleaning tank with fluff, and the fluff pre-cleans the outer wall and the inner wall of the bottom end of the sampling cylinder.

[0027] The present invention also provides a method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments, based on the above-mentioned device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments, comprising the following steps:

[0028] S1: Load the sealing unit, cleaning unit, and pressure-maintaining unit on the fixing frame, temporarily insert the sampling cartridge into the cleaning unit, open the first ball valve, and inject gas at a certain pressure into the pressure-maintaining unit to connect the pressure-maintaining unit with the sealing unit;

[0029] S2: Lowering the device to the target seabed area, removing the sampling tube from the cleaning unit using a handle, and inserting the sampling tube into the seabed sediment to a certain depth for sampling; during the sampling process, as the sediment enters the sampling tube, the seawater in the sampling tube is squeezed and discharged from the drain port;

[0030] S3: closing the first ball valve, using negative pressure to maintain the integrity of the seabed sediment in the sampling tube, and pulling the sampling tube out of the seabed sediment;

[0031] S4: inserting the sampling tube with seabed sediment into the cleaning unit and moving it up and down to perform pre-cleaning;

[0032] S5: Connect the pre-cleaned sampling tube to the sealing unit to maintain pressure and seal;

[0033] S6: After the sealing is completed, the device is recovered to the sea surface to complete the sampling of seabed sediments.

[0034] Preferably, in step S5, during the process of inserting the pre-cleaned sampling cylinder into the sealing assembly of the sealing unit, the outer wall of the lower end of the sampling cylinder first squeezes the sealing claw, causing the sealing claw to move toward the outside of the sealing platform, and at the same time compresses the claw spring until the bottom of the sampling cylinder contacts the sealing base. At this time, the claw spring rebounds, and all the sealing claws are completely embedded in the various grooves on the outer wall of the lower end of the sampling cylinder, completing the claw-type seal.

[0035] Preferably, in steps S1 to S6, the second ball valve and the connecting valve are both in an open state, so that the sealing assembly and the seawater cavity of the pressure-maintaining cylinder remain in communication;

[0036] When the pre-cleaned sampling cylinder is inserted into the sealing unit, the seawater in the inner cavity of the sealing component is squeezed into the pressure-maintaining cylinder through the second ball valve and the connecting valve. At this time, the piston in the pressure-maintaining cylinder is displaced and the gas is compressed accordingly.

[0037] After the sealing is completed, the sampling cylinder and the pressure-maintaining cylinder remain connected. During the process of recovering the device to the sea surface, the ambient pressure drops. If a slight leak occurs in the sampling cylinder, the gas in the pressure-maintaining cylinder will expand, thereby maintaining the pressure in the sampling cylinder.

[0038] Preferably, at least one of the devices is mounted on an ROV platform, and multi-sequence sampling and rapid pressure-maintaining sealing of seabed sediments are achieved based on the ROV manipulator.

[0039] In response to problem 1) in the background technology, the present invention adopts a negative pressure sampling method. By setting a ball valve at the top of the sampling cylinder, negative pressure is generated in the sampling cylinder by opening and closing the ball valve. Negative pressure sampling can not only complete the collection of sediments, but also prevent the sediments from falling off.

[0040] In response to problem 2) in the background technology, the present invention adopts a pre-cleaning method. By setting up a cleaning unit, it is only necessary to clean the mud and sand on the sampling tube in the cleaning unit before sealing, which can significantly reduce the problem of damage to the sealing ring. Not only is the operation simple, but the cost is also low.

[0041] In response to problem 3) in the background technology, the present invention adopts a gas pressure maintenance method, by setting a pressure maintaining unit and utilizing the high compression capacity of nitrogen to reduce the rapid drop in system pressure caused by micro-leakage.

[0042] In response to problem 4) in the background technology, the device of the present invention improves the operability of sequence addition by setting up a simplified mechanical sealing structure; the device adopts a claw sealing method, and the sealing mechanical structure is small, simple and convenient, and can be inserted by a manipulator to quickly achieve high-pressure sealing of the pressure-maintaining barrel; the overall layout of the device is also very compact and simple, so it can be similar to the non-pressure-maintaining multi-sequence Pushcore commonly carried by ROVs, and can quickly achieve the increase or decrease of sampling sequences.

[0043] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0044] The present invention provides a device and method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments. The device significantly reduces sediment cutting disturbances through negative pressure sampling; significantly improves the success rate of pressure maintenance by pre-cleaning the sampling tube; reduces the deviation between the system pressure and the in-situ pressure after the sampling process by adding a gas pressure-maintaining structure; and achieves fast and efficient sealing of the sampling tube through a simple mechanical structure.

[0045] The present invention has the following beneficial effects:

[0046] 1) The combination of pre-cleaning and claw sealing significantly improves the sealing success rate and achieves fast, efficient and high-pressure sealing;

[0047] 2) The high-pressure ball valve negative pressure and gas pressure-maintaining coupling sampling method reduces the disturbance of the sampling process to the sediment and achieves the compressibility of seawater, further solving the compression problem existing in negative pressure sampling;

[0048] 3) The device simplifies the pressure-maintaining mechanical structure and the overall structure, improving the operability of sequence increase and decrease. Due to the simple structure of the device, the present invention can increase or decrease the sampling sequence as needed within the ROV carrying capacity, achieving multi-sequence sampling in a single ROV dive, greatly improving sampling efficiency, avoiding the problem of requiring an ROV dive for each sampling sequence, and significantly reducing operation time and costs.

[0049] 4) The device and method proposed in this invention can provide important support for further scientific research on marine geology and microorganisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a structural diagram of a device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments provided in Example 1.

[0051] Figure 2 This is an overall structural diagram of the sampling unit 1 and the sealing unit 2 provided in Example 1.

[0052] Figure 3This is an overall cross-sectional view of the sampling unit 1 and the sealing unit 2 provided in Example 1.

[0053] Figure 4 This is a bottom view of the sealing unit 2 provided in Example 1.

[0054] Figure 5 This is a partially enlarged cross-sectional view of the sealing assembly 22 provided in Example 1.

[0055] Figure 6 Schematic diagram of the device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments using the ten sequences provided in Example 1.

[0056] Figure 7 This is a flow chart of a method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments provided in Example 2. DETAILED DESCRIPTION

[0057] The accompanying drawings are for illustrative purposes only and are not to be construed as limiting this patent;

[0058] In order to better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product size;

[0059] It is understandable to those skilled in the art that some well-known structures and descriptions thereof may be omitted in the drawings.

[0060] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0061] Example 1

[0062] like Figure 1 As shown, this embodiment provides a device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments, comprising: a sampling unit 1, a sealing unit 2, a cleaning unit 3, a pressure-maintaining unit 4, and a fixing frame 5; the sampling unit 1, the sealing unit 2, the cleaning unit 3, and the pressure-maintaining unit 4 are respectively mounted on the fixing frame 5;

[0063] The sampling unit 1 is used for insertable negative pressure sampling of seabed sediments and includes: a handle 11, a first ball valve 12, and a sampling barrel 13; the lower end of the handle 11 is threadedly connected to the upper end of the first ball valve 12, and the lower end of the first ball valve 12 is threadedly connected to the upper end of the sampling barrel 13; the lower end of the handle 11 is hollow and provided with a drain 111; the sampling barrel 13 is a hollow cylindrical structure; the drain 111 is connected to the sampling barrel 13 through the first ball valve 12;

[0064] The sampling cylinder 13 is detachably connected to the sealing unit 2. After the sampling unit 1 completes sampling of seabed sediments, the sampling cylinder 13 is connected to the sealing unit 2 to achieve pressure-maintaining sealing of the sampling cylinder 13.

[0065] The sampling cylinder 13 can be inserted into the cleaning unit 3 for cleaning, thereby pre-cleaning the outer wall and the inner wall of the bottom end of the sampling cylinder 13;

[0066] The pressure-maintaining unit 4 includes: a pressure-maintaining cylinder 41, a piston 42, an air injection valve 43 and a connecting valve 44; the pressure-maintaining cylinder 41 is a hollow cylindrical structure, the upper end of the pressure-maintaining cylinder 41 is connected to the air injection valve 43, and the lower end is connected to one end of the connecting valve 44; the other end of the connecting valve 44 is connected to the sealing unit 2; the piston 42 is movably arranged inside the pressure-maintaining cylinder 41 to isolate the seawater cavity and the air cavity inside the pressure-maintaining cylinder 41. In this embodiment, the air cavity inside the pressure-maintaining cylinder 41 is filled with nitrogen at a certain pressure; the pressure-maintaining unit 4 is used to carry the discharged seawater when the sealing unit 2 seals the sampling cylinder 13, and to maintain the pressure inside the sampling unit 1 after the sealing is completed to prevent micro-leakage;

[0067] In the sampling unit, the handle is a T-shaped handle;

[0068] The outer wall of the lower end of the sampling tube 13 is provided with a plurality of grooves 131;

[0069] The sealing unit 2 includes: an inlet groove 21, a sealing assembly 22 and a second ball valve 23;

[0070] The introduction groove 21 is provided at the upper end of the sealing assembly 22. The introduction groove 21 is a tapered groove structure with an upwardly flared opening, and is used to assist the sampling cylinder 13 in accurately inserting into the sealing assembly 22.

[0071] The sealing assembly 22 is a cylindrical structure as a whole, including: a plurality of sealing claws 221, the same number as the grooves 131, a sealing platform 222, and a sealing base 223; the sealing platform 222 and the sealing base 223 are threadedly connected; the lower end of the sealing base 223 is threadedly connected to the upper end of the second ball valve 23; the plurality of sealing claws 221 are respectively nested in the plurality of claw cavities 2221 of the sealing platform 222, and are respectively telescopically connected to the sealing platform 222 via claw springs 2211; the sealing platform 222 and the sealing base 223 are also respectively provided with a first sealing groove 2222 and a second sealing groove 2231 for mounting a sealing ring;

[0072] The sampling cylinder 13 is pluggably connected to the sealing platform 222. When the sampling cylinder 13 is inserted into the sealing platform 222, a plurality of sealing claws 221 are respectively embedded in the grooves 131 on the outer wall of the lower end of the sampling cylinder 13 to achieve claw-type sealing.

[0073] The lower end of the second ball valve 23 is connected to the connecting valve 44;

[0074] The cleaning unit 3 is specifically a cleaning tank with fluff inside. The sampling tube 13 is inserted into the cleaning tank with fluff, and the fluff pre-cleans the outer wall and the inner wall of the bottom end of the sampling tube 13.

[0075] In the specific implementation process, the device in this embodiment is mainly composed of a sampling unit 1, a sealing unit 2, a cleaning unit 3, a pressure maintaining unit 4 and a fixing frame 5;

[0076] like Figure 1 and 2 As shown, the sampling unit 1 is mainly used for inserting negative pressure sampling of seabed sediments, and the sealing unit 2 is used to maintain pressure and seal the sampling cylinder 13 after the sampling unit 1 completes the sampling of seabed sediments. There is a cavity inside the sealing unit 2, and the sampling cylinder 13 can be sealed by inserting the cavity;

[0077] The sampling unit 1 includes, from top to bottom, a handle 11, a first ball valve 12, and a sampling barrel 13. The handle 11 is provided with a drain port 111. The drain port 111 is connected to the sampling barrel 13 through the first ball valve 12 for draining seawater during the sampling process.

[0078] In this embodiment, the cleaning unit 3 is a cleaning tank with fluff inside, which is used to pre-clean the outer wall and the inner wall of the bottom end of the sampling tube 13 before sealing to prevent a large amount of mud and sand from adhering to the wall of the sampling tube 13;

[0079] The pressure-maintaining unit 4 is in communication with the sealing unit 2 and is used to carry the discharged seawater when the sealing unit 2 seals the sampling cylinder 13, thereby compressing the seawater in an equal amount and ensuring the feasibility of the seal between the sampling cylinder 13 and the sealing unit 2. Furthermore, after the seal is completed, the pressure inside the sampling unit 1 is maintained to prevent a rapid decrease in the system pressure in the sampling cylinder 13 caused by micro-leakage.

[0080] In this embodiment, the fixing frame 5 is a fixed frame for loading and fixing the sampling unit 1, the sealing unit 2, the cleaning unit 3 and the pressure holding unit 4, and is fixed to the ROV platform; according to the sampling quantity requirements, the carrying capacity of the fixing frame 5 can be changed to achieve multi-sequence sampling;

[0081] In the sampling unit 1, the sampling cylinder 13 is mainly used for pressure-maintaining sampling of seabed sediments. After the device returns to the deck of the ship, it must be ensured to withstand the internal high pressure; a number of grooves 131 are cut into the lower end of the sampling cylinder 13 for claw-type sealing between the sampling cylinder 13 and the sealing unit 2; the upper end of the sampling cylinder 13 is connected to the lower end of the first ball valve 12 by a thread, and the lower end of the T-shaped handle 11 is connected to the upper end of the first ball valve 12 by a thread. The shape design of the T-shaped handle 11 is mainly convenient for the ROV manipulator to hold it; in addition, the interior of the lower end of the T-shaped handle 11 is hollow, and a drain port 111 is designed at the upper part of the hollow section to pass through the handle 11 for discharging seawater in the sampling cylinder 13 during the sampling process; the first ball valve 12 is used to connect the sampling cylinder 13 and the drain port 111, and to form a negative pressure inside the sampling cylinder 13 when the sampling cylinder 13 is pulled out of the seabed sediment;

[0082] During the sampling process of inserting the sampling cylinder 13 into the seabed sediment, the first ball valve 12 is opened. As the sediment enters the sampling cylinder 13, the seawater above the sampling cylinder 13 is squeezed and discharged from the drain port 111 of the T-shaped handle 11. After the sampling cylinder 13 is inserted to the target depth, the first ball valve 12 is closed, and then the ROV manipulator pulls the sampling cylinder 13 out of the seabed sediment. Due to the negative pressure inside the sampling cylinder 13 system relative to the external environment formed by the closing of the first ball valve 12, the sediment is basically kept from falling off, thereby ensuring the integrity of the sample.

[0083] In this embodiment, the sealing unit 2 includes: an inlet groove 21, a sealing assembly 22 and a second ball valve 23; the inlet groove 21 is arranged at the upper end of the sealing assembly 22, the lower end of the sealing assembly 22 is threadedly connected to the upper end of the second ball valve 23, and the lower end of the second ball valve 23 is connected to the pressure holding unit 4; the inlet groove 21 is a tapered groove structure with an upward flaring, which is used to assist the sampling cylinder 13 to be accurately inserted into the sealing assembly 22. This is because ROV video monitoring is usually a two-dimensional observation, and it is difficult to accurately identify the relative positions of the device components in the figure. By designing the tapered inlet groove 21 with an upward flaring, the ROV manipulator can be assisted to insert the sampling cylinder 13 into the sealing assembly 22 more quickly.

[0084] like Figures 3-5 As shown, the sealing assembly 22 is used to perform claw-type sealing on the lower end of the sampling tube 13; the sealing assembly 22 is a cylindrical structure as a whole, including: a plurality of sealing claws 221, a sealing platform 222 and a sealing base 223; the sealing platform 222 and the sealing base 223 are connected by threads, and the sealing claws 221 are loaded in the claw cavity 2221 of the sealing platform 222; in this embodiment, the sealing claws 221 are mounted in the claw cavity 2221 of the sealing platform 222. Figure 4In this embodiment, 8 sealing claws 221 are designed, and the number is not limited to 8 and can be increased or decreased according to actual needs; the sealing claws 221 are nested in the claw springs 2211. When not subjected to external force, the claw springs 2211 are stretched, pushing the sealing claws 221 to move toward the inside of the sealing platform 222. There is a local space limit between the sealing claws 221 and the sealing platform 222, so that the sealing claws 221 will not completely break away from the claw springs 2211 and enter the inner cavity of the sealing base 223 as a whole; in addition, the present embodiment further opens a first sealing groove 2222 and a second sealing groove 2231 on the sealing platform 222 and the sealing base 223, respectively. During the sampling process, sealing rings are installed in the grooves for double sealing with the sampling cylinder 13;

[0085] During sampling, when the sampling cylinder 13 is inserted into the sealing assembly 22, the arc surface at the lower end of the sampling cylinder 13 first squeezes the sealing claw 221, causing the sealing claw 221 to move outward from the sealing platform 222 until the bottom of the sampling cylinder 13 is in axial contact with the sealing base 223. The sealing claw 221 is completely embedded in the groove 131 on the outer wall of the sampling cylinder 13, and the sealing process is completed.

[0086] The cleanliness and integrity of the sealing ring surfaces loaded in the first sealing groove 2222 and the second sealing groove 2231 are the key to achieving high-pressure sealing. Therefore, before inserting the sampling cylinder 13 into the sealing unit 2, it is necessary to first clean the inner and outer surfaces of the lower end of the sampling cylinder 13 after sediment sampling. This process is mainly implemented in the cleaning unit 2 (cleaning tank); a certain amount of fluff is embedded in the cleaning tank. After the ROV manipulator pulls the sampling cylinder 13 out of the seabed sediment, the sampling cylinder 13 is first inserted into the cleaning tank for surface brushing. After ensuring that there is no obvious mud and sand on the surface of the sampling cylinder 13, the sealing between the sampling cylinder 13 and the sealing component 22 is performed;

[0087] In this embodiment, the pressure-maintaining unit 4 includes: a pressure-maintaining cylinder 41, a piston 42, an injection valve 43, and a connecting valve 44; the lower end of the sealing base 223 is connected to the upper end of the second ball valve 23 by a thread, the lower end of the second ball valve 23 is connected to one end of the connecting valve 44 by a pipeline, and the other end of the connecting valve 44 is connected to one end of the pressure-maintaining cylinder 41; the other end of the pressure-maintaining cylinder 41 is connected to the injection valve 43, through which high-pressure nitrogen can be injected into the pressure-maintaining cylinder 41; the pressure-maintaining cylinder 41 contains a piston 42 with a movable rod, which is used to isolate nitrogen and seawater during the sampling process; during the sampling process, the second ball valve 23 and the connecting valve 44 are always kept open, so that the sealing assembly 22 and the water cavity end of the pressure-maintaining cylinder 41 remain connected;

[0088] When the sampling cylinder 13 is inserted into the sealing assembly 22, the seawater in the inner cavity of the sealing assembly 22 can pass through the second ball valve 23 and the connecting valve 44 and be squeezed into the pressure-maintaining cylinder 41. At this time, the nitrogen in the pressure-maintaining cylinder 41 is compressed accordingly. Since the pressure of the gas and seawater at both ends of the piston 42 is equal when on the seabed, the insertion of the sampling cylinder 13 into the sealing assembly 22 can be achieved by simply overcoming the friction force of the piston 42 and the force of the compressed nitrogen. After the sealing between the sampling cylinder 13 and the sealing assembly 22 is completed, the sampling cylinder 13 and the pressure-maintaining cylinder 41 remain connected. Therefore, when the device is recovered to the ambient pressure drop on the deck of the ship, when a slight leak occurs in the sampling cylinder 13, the nitrogen in the pressure-maintaining cylinder 41 will expand, thereby maintaining the pressure in the sampling cylinder 13 to a certain extent, so that the pressure does not drop rapidly.

[0089] The device can expand the loading sequence on the fixed frame 5 according to the needs to achieve multi-sequence sampling and improve the sampling efficiency, such as Figure 6 The following is an example of the appearance of loading ten sequences;

[0090] The present device adopts a combined pre-cleaning and claw sealing method, which significantly improves the sealing success rate and realizes fast, efficient and high-pressure sealing. Although the claw sealing method alone can achieve a certain probability of successful sealing, the probability of failure of the sealing surface will be significantly increased. In addition, due to the adhesion of mud and sand, mud and sand may be stuck between the contact surfaces of the two components during the insertion of the sampling tube 13 into the sealing assembly 22, making the insertion more difficult. This is mainly because the ROV monitoring image is generally two-dimensional, and it is difficult to insert it completely vertically. Once an angle deviation occurs, coupled with mud and sand obstruction, the insertion process will be disturbed, and this process may also cause wear of the sealing ring.

[0091] In addition, the device adopts a sampling method of coupling the negative pressure of a high-pressure ball valve with the gas pressure maintenance, which reduces the disturbance of the sampling process to the sediment and realizes the compressibility of seawater in equal amounts; the device can reduce the damage to the sediment process through negative pressure sampling; however, after the sampling is completed, due to the low compression of seawater, the insertion process of the sampling tube 13 into the sealing component 22 is actually impossible to achieve; since the cavity of the sealing component 22 itself is also full of seawater, this part of water needs to be discharged during the downward pressure of the sampling tube 13, but when the sealing ring forms a seal, this part of water cannot be discharged, and the sampling tube 13 can only be inserted into the sealing component 22 by compression, which is difficult to achieve; another The method is to open the first ball valve 12 to drain water after the sampling cylinder 13 is basically inserted into the sealing component 22; however, this process is difficult to implement for the ROV manipulator, which can only open or close the ball valve in one direction; the device connects the pressure maintaining unit 4 with the sampling cylinder 13, so that the water pressure in the cavity of the sampling unit 1 and the air pressure in the pressure maintaining unit 4 are equal. Then, in the process of inserting the sampling cylinder 13 into the sealing component 22, it only needs to overcome the movement resistance of the piston 42 in the pressure maintaining cylinder 41 to achieve downward insertion; in addition, the air pressure of the pressure maintaining cylinder 41 itself can maintain the pressure inside the sampling cylinder 13, reducing the problem of rapid drop in system pressure due to local micro-leakage.

[0092] Example 2

[0093] like Figure 7 As shown, this embodiment provides a method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments. Based on the device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments described in Example 1, at least one of the devices is mounted on an ROV platform, and multi-sequence sampling and rapid pressure-maintaining sealing of seabed sediments are achieved based on the ROV manipulator, comprising the following steps:

[0094] S1: Load the sealing unit 2, cleaning unit 3, and pressure holding unit 4 on the fixing frame 5, temporarily insert the sampling cylinder 13 into the cleaning unit 3, open the first ball valve 12, and inject gas at a certain pressure into the pressure holding unit 4 to connect the pressure holding unit 4 with the sealing unit 2;

[0095] S2: The device is lowered to the target seabed area, the sampling cylinder 13 is removed from the cleaning unit 3 using the handle 11, and the sampling cylinder 13 is inserted into the seabed sediment to a certain depth for sampling; during the sampling process, as the sediment enters the sampling cylinder 13, the seawater in the sampling cylinder 13 is squeezed and discharged from the drain 111;

[0096] S3: closing the first ball valve 12, using negative pressure to maintain the integrity of the seabed sediment in the sampling tube 13, and pulling the sampling tube 13 out of the seabed sediment;

[0097] S4: inserting the sampling tube 13 with the seabed sediment into the cleaning unit 3 and moving it up and down to perform pre-cleaning;

[0098] S5: Connect the pre-cleaned sampling tube 13 to the sealing unit 2 to maintain pressure and seal;

[0099] S6: After the sealing is completed, the device is recovered to the sea surface to complete the sampling of seabed sediments.

[0100] In step S5, during the process of inserting the pre-cleaned sampling cylinder 13 into the sealing assembly 22 of the sealing unit 2, the outer wall of the lower end of the sampling cylinder 13 first squeezes the sealing claw 221, causing the sealing claw 221 to move toward the outside of the sealing platform 222, while compressing the claw spring 2211 until the bottom of the sampling cylinder 13 contacts the sealing base 223. At this time, the claw spring 2211 rebounds, and all the sealing claws 221 are completely embedded in the grooves 131 of the outer wall of the lower end of the sampling cylinder 13, completing the claw-type seal;

[0101] In steps S1 to S6, the second ball valve 23 and the connecting valve 44 are both in an open state, so that the sealing assembly 22 and the seawater cavity of the pressure-maintaining cylinder 41 remain in communication;

[0102] When the pre-cleaned sampling cylinder 13 is inserted into the sealing unit 2, the seawater in the inner cavity of the sealing assembly 22 is squeezed into the pressure-maintaining cylinder 41 through the second ball valve 23 and the connecting valve 44. At this time, the piston 42 in the pressure-maintaining cylinder 41 is displaced, and the gas is compressed accordingly.

[0103] After the sealing is completed, the sampling cylinder 13 and the pressure-maintaining cylinder 41 remain connected. During the process of recovering the device to the sea surface, the ambient pressure drops. If a slight leak occurs in the sampling cylinder 13, the gas in the pressure-maintaining cylinder 41 will expand, thereby maintaining the pressure in the sampling cylinder 13.

[0104] In the specific implementation process, before the device is put into water, the entire device is first cleaned, and then nitrogen gas with a certain pressure is injected into the air cavity of the pressure-maintaining cylinder 41 through the injection valve 43;

[0105] Then, connect all the components of the device and load them on the front of the ROV platform; temporarily place the sampling cylinder 13 in the cleaning unit 2 and take out the sample after reaching the seabed; at the same time, open the first ball valve 12, the second ball valve 23 and the connecting valve 44;

[0106] The entire device then descends with the ROV until it reaches the target area and sits on the bottom, where it can prepare for the sampling process.

[0107] The ROV manipulator then holds the T-shaped handle 11 and removes the sampling cylinder 13 from the cleaning unit 2. The sampling cylinder 13 is then inserted into the seabed sediment to a certain depth for sampling. During the sampling process, as the sediment enters the sampling cylinder 13, the seawater in the sampling cylinder 13 is squeezed and discharged from the drain 111.

[0108] After sampling is completed, the ROV manipulator closes the first ball valve 12, then grasps the T-shaped handle 11 and pulls the sampling tube 13 containing sediment out of the seabed sediment. Due to the negative pressure inside the sampling tube 13 relative to the surrounding environment formed by closing the first ball valve 12, the mud inside the sampling tube 13 will not fall off in large quantities.

[0109] The ROV manipulator inserts the sampling tube 13 into the cleaning unit 2 and repeatedly moves the sampling tube 13 in the axial direction of the cleaning unit 2 by moving it up and down. The fluff embedded in the cleaning unit 2 is used to scrub the mud and sand on the outer wall of the sampling tube 13 and the inner wall of the bottom end of the sampling tube 13, thereby reducing the subsequent sealing problems caused by the mud and sand adhering to the wall of the sampling tube 13.

[0110] After the pre-cleaning is completed, the ROV manipulator takes the sampling cylinder 13 out of the cleaning unit 2 and inserts it into the sealing assembly 22; in the process of inserting the pre-cleaned sampling cylinder 13 into the sealing assembly 22 of the sealing unit 2, the outer wall of the lower end of the sampling cylinder 13 will first contact the sealing claw 221. Since the contact surfaces of the two do not offset each other, the sealing claw 221 will be squeezed to move to the outside of the sealing platform 222, and at the same time compress the claw spring 2211 until the bottom of the sampling cylinder 13 contacts the sealing base 223. At this time, the claw spring 2211 rebounds, and all the sealing claws 221 are completely embedded in the respective grooves 131 on the outer wall of the lower end of the sampling cylinder 13, completing the claw-type seal;

[0111] After sealing is completed, the ROV is recovered to the shipboard deck unit, and the sampling process is completed;

[0112] This method significantly reduces the disturbance caused by cutting the sediment through negative pressure sampling; significantly improves the success rate of pressure maintenance by pre-cleaning the sampling tube 13; reduces the deviation between the system pressure and the in-situ pressure after the sampling process by adding a gas pressure-maintaining structure; and achieves fast and efficient sealing of the sampling tube 13 through a simple mechanical structure. Due to the simple structure of the device, the sampling sequence can be increased or decreased as needed within the carrying capacity of the ROV, achieving multi-sequence sampling in a single ROV dive and significantly improving the sampling efficiency. This method can provide important support for further scientific research on marine geology, microorganisms, etc.

[0113] The same or similar reference numerals correspond to the same or similar components;

[0114] The terms used in the drawings to describe positional relationships are for illustrative purposes only and should not be construed as limiting this patent;

[0115] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments, characterized in that: include: A sampling unit (1), a sealing unit (2), a cleaning unit (3), a pressure-maintaining unit (4) and a fixing frame (5); the sampling unit (1), the sealing unit (2), the cleaning unit (3) and the pressure-maintaining unit (4) are respectively mounted on the fixing frame (5); The sampling unit (1) is used for inserting negative pressure sampling of seabed sediments, and comprises: a handle (11), a first ball valve (12) and a sampling barrel (13); the lower end of the handle (11) is connected to the upper end of the first ball valve (12), and the lower end of the first ball valve (12) is connected to the upper end of the sampling barrel (13); the lower end of the handle (11) is hollow inside and provided with a drain outlet (111); the sampling barrel (13) is a hollow cylindrical structure; the drain outlet (111) and the sampling barrel (13) are connected through the first ball valve (12); The sampling cylinder (13) is detachably connected to the sealing unit (2); after the sampling unit (1) completes sampling of seabed sediments, the sampling cylinder (13) is connected to the sealing unit (2) to achieve pressure-maintaining sealing of the sampling cylinder (13); The sampling cylinder (13) can be inserted into the cleaning unit (3) for cleaning, thereby achieving pre-cleaning of the outer wall and the inner wall of the bottom end of the sampling cylinder (13); The pressure-maintaining unit (4) comprises: a pressure-maintaining cylinder (41), a piston (42), an air injection valve (43) and a connecting valve (44); the pressure-maintaining cylinder (41) is a cylindrical structure with a hollow interior, the upper end of the pressure-maintaining cylinder (41) is connected to the air injection valve (43), and the lower end is connected to one end of the connecting valve (44); the other end of the connecting valve (44) is connected to the sealing unit (2); the piston (42) is movably arranged inside the pressure-maintaining cylinder (41) and is used to isolate the seawater cavity and the air cavity inside the pressure-maintaining cylinder (41).

2. The device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to claim 1, characterized in that: In the sampling unit (1), the handle (11) is a T-shaped handle.

3. The device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to claim 1, characterized in that: The outer wall of the lower end of the sampling cylinder (13) is provided with a plurality of grooves (131); The sealing unit (2) comprises: an introduction groove (21), a sealing assembly (22) and a second ball valve (23); The introduction groove (21) is arranged at the upper end of the sealing component (22), and the introduction groove (21) is a tapered groove structure with an expanded opening facing upward; The sealing assembly (22) is a cylindrical structure as a whole, comprising: a plurality of sealing claws (221) the same number as the grooves (131), a sealing platform (222) and a sealing base (223); the sealing platform (222) and the sealing base (223) are connected; the lower end of the sealing base (223) is connected to the upper end of the second ball valve (23); the plurality of sealing claws (221) are respectively nested in the plurality of claw cavities (2221) of the sealing platform (222), and are respectively telescopically connected to the sealing platform (222) via claw springs (2211); the contact surfaces of the sealing platform (222) and the sealing base (223) are equipped with sealing rings; The sampling cylinder (13) and the sealing platform (222) are pluggably connected. When the sampling cylinder (13) is inserted into the sealing platform (222), a plurality of sealing claws (221) are respectively embedded in the grooves (131) on the outer wall of the lower end of the sampling cylinder (13), thereby realizing claw-type sealing. The lower end of the second ball valve (23) is communicated with the connecting valve (44).

4. The device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to claim 3, characterized in that: The sealing platform (222) and the sealing base (223) are respectively provided with a first sealing groove (2222) and a second sealing groove (2231) for installing a sealing ring.

5. The device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to claim 3, characterized in that: The lower end of the handle (11) is threadedly connected to the upper end of the first ball valve (12), and the lower end of the first ball valve (12) is threadedly connected to the upper end of the sampling cylinder (13); The sealing platform (222) and the sealing base (223) are threadedly connected; the lower end of the sealing base (223) is threadedly connected to the upper end of the second ball valve (23).

6. The device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to claim 1, characterized in that: The cleaning unit (3) is specifically a cleaning tank with fluff inside. The sampling tube (13) is inserted into the cleaning tank with fluff, and the fluff pre-cleans the outer wall and the inner wall of the bottom end of the sampling tube (13).

7. A method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments, based on the device for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: The sealing unit (2), the cleaning unit (3) and the pressure-maintaining unit (4) are loaded on the fixing frame (5), the sampling cylinder (13) is temporarily inserted into the cleaning unit (3), the first ball valve (12) is opened, and gas of a certain pressure is injected into the pressure-maintaining unit (4), so as to connect the pressure-maintaining unit (4) with the sealing unit (2); S2: lowering the device to the target seabed area, taking out the sampling cylinder (13) from the cleaning unit (3) using the handle (11), and inserting the sampling cylinder (13) into the seabed sediment to a certain depth for sampling; During the sampling process, as sediment enters the sampling cylinder (13), the seawater in the sampling cylinder (13) is squeezed and discharged from the drain port (111); S3: After the sampling is completed, the first ball valve (12) is closed, the integrity of the seabed sediment in the sampling tube (13) is maintained by using negative pressure, and the sampling tube (13) is pulled out from the seabed sediment; S4: inserting the sampling tube (13) with the seabed sediment into the cleaning unit (3) and moving it up and down to perform pre-cleaning; S5: Connecting the pre-cleaned sampling tube (13) to the sealing unit (2) to perform pressure-maintaining sealing; S6: After the sealing is completed, the device is recovered to the sea surface to complete the sampling of seabed sediments.

8. The method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to claim 7, characterized in that: In step S5, during the process of inserting the pre-cleaned sampling cylinder (13) into the sealing assembly (22) of the sealing unit (2), the outer wall of the lower end of the sampling cylinder (13) first squeezes the sealing claw (221), causing the sealing claw (221) to move toward the outside of the sealing platform (222), and at the same time compresses the claw spring (2211) until the bottom of the sampling cylinder (13) contacts the sealing base (223). At this time, the claw spring (2211) rebounds, and all the sealing claws (221) are completely embedded in the various grooves (131) of the outer wall of the lower end of the sampling cylinder (13), completing the claw-type seal.

9. The method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to claim 7, characterized in that: In the steps S1 to S6, the second ball valve (23) and the connecting valve (44) are both in an open state, so that the sealing component (22) and the seawater cavity of the pressure-maintaining cylinder (41) remain in communication; When the pre-cleaned sampling cylinder (13) is inserted into the sealing unit (2), the seawater in the inner cavity of the sealing component (22) is squeezed into the pressure-maintaining cylinder (41) through the second ball valve (23) and the connecting valve (44). At this time, the piston (42) in the pressure-maintaining cylinder (41) is displaced, and the gas is compressed accordingly; After the sealing is completed, the sampling cylinder (13) and the pressure-maintaining cylinder (41) remain connected. During the process of recovering the device to the sea surface, the ambient pressure drops. If a slight leak occurs in the sampling cylinder (13), the gas in the pressure-maintaining cylinder (41) will expand, thereby maintaining the pressure in the sampling cylinder (13).

10. A method for low-disturbance sampling and pressure-maintaining sealing of seabed sediments according to any one of claims 7 to 9, characterized in that: At least one of the devices is mounted on an ROV platform, and multi-sequence sampling and rapid pressure-maintaining sealing of seabed sediments are achieved based on the ROV manipulator.

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