In-situ layered pore water sampler for deep-sea sediments

Abstract

This invention proposes an in-situ stratified sampler for pore water in deep-sea sediments, belonging to the fields of deep-sea exploration and marine geological engineering. It solves the problems of existing sampling methods, such as the inability to preserve sediment in situ and difficulties in sealing. It includes a sampler with a sampling chamber having an opening near the sediment; a drive assembly for actuating the sampler to collect sediment from the opening into the sampling chamber; stratification sections, each slidably connected to the sampling chamber, with one end connected to a pulling part and the other end connected to a sealing part, used to separate the sediment in the sampling chamber into several layers under the traction of the pulling part; the sealing part is used to unfold after being pulled by the stratification sections, separating and sealing adjacent layers of sediment; and a pore water treatment assembly, coupled with the stratification sections, communicating with the stratified sediments and filtering water from the corresponding sediment layers. It is mainly used for sediment sampling and obtaining pore water along a vertical gradient.

Description

Technical Field

[0001] This invention belongs to the field of deep-sea exploration and marine geological engineering, and in particular relates to an in-situ stratified sampler for pore water in deep-sea sediments. Background Technology

[0002] As a crucial and underexplored area of ​​Earth, the deep sea contains vital information about biogeochemical cycles and paleoenvironmental evolution at the sediment-pore water interface. Obtaining in-situ layered samples of this interface is a core prerequisite for deep-sea scientific research. Currently, various deep-sea sediment sampling equipment (such as pressure-holding sampling cylinders and visual controllable samplers) have been developed both domestically and internationally. While these equipment can achieve pressure-holding or low-disturbance sediment sampling, pore water requires subsequent extraction via squeezing or centrifugation, which can easily damage the sediment's pore structure and lead to sample distortion. On the other hand, pore water sampling techniques (such as permeation and differential pressure methods) can extract pore water with low disturbance, but they cannot simultaneously obtain sediments from the same layer and suffer from slow sampling rates and insufficient sample yields.

[0003] The core deficiency of existing technologies lies in their inability to achieve in-situ, simultaneous, and layered sampling of sediments and corresponding pore water layers. This makes it difficult to accurately capture the true chemical gradient and interlayer coupling relationships at the sediment-pore water interface, hindering the advancement of research in deep-sea biogeochemical cycles, resource exploration, and environmental assessment. Therefore, there is an urgent need to develop an in-situ sampling device capable of simultaneously and minimally disturbing layered sediments and pore water. Summary of the Invention

[0004] In view of this, the present invention aims to propose an in-situ stratified sampler for deep-sea sediment pore water to solve the problems of existing sampling methods that cannot be preserved in situ and are difficult to seal.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an in-situ stratified sampler for pore water in deep-sea sediments, comprising:

[0006] A sampler is provided with a sampling chamber, and the sampling chamber has an opening on the side near the sediment.

[0007] A drive assembly, connected to the sampler, is used to drive the sampler to collect sediment from the opening into the sampling chamber, wherein the drive assembly is coupled to the pulling part;

[0008] The sampling chamber has several stratification sections spaced apart along its axial direction. Each stratification section is slidably connected to the sampling chamber. One end of each stratification section is connected to a pulling section, and the other end is connected to a sealing section. The stratification section is used to separate the sediment in the sampling chamber into several layers under the traction of the pulling section. The sealing section is used to unfold after being pulled by the stratification section to separate and seal two adjacent layers of sediment that have been cut apart.

[0009] The pore water treatment component is provided in several parts and slidably mounted on the sampler. It is used to couple with the stratification section and communicate with the stratified sediments. After filtering the water in the corresponding sediment layer, it completes the sealing of the corresponding sediment layer and the filtered water.

[0010] Furthermore, the pore water treatment assembly includes a filter element, a pore water storage chamber, and a piston. The filter element is located on the side of the pore water storage chamber near the sampler, and the piston is slidably mounted inside. The piston divides the pore water storage chamber into two chambers, one of which is connected to the filter element, and the other chamber has adjustable pressure. The filter element is used to filter water entering one chamber when it is connected to the corresponding layer of sediment. The outer wall of the pore water storage chamber is used to seal the corresponding layer of sediment when the filter element is misaligned with the corresponding layer of sediment.

[0011] Furthermore, the other cavity is pre-filled with gas at a certain pressure and then sealed.

[0012] Furthermore, the sampler includes an inner cylinder and an outer cylinder arranged coaxially, the sampling chamber is disposed inside the inner cylinder, and the pore water treatment component is slidably disposed on the outer wall of the inner cylinder and housed inside the outer cylinder.

[0013] Furthermore, the drive assembly includes a lead screw, a deep-sea motor, a transmission part, and a winding part. The shaft of the deep-sea motor is connected to the lead screw and the winding part respectively through the transmission part. The lead screw is connected to the sampler to drive the sampler to move along the lead screw axis. The winding part is used to wind up or release the traction part.

[0014] Furthermore, the pulling part has a winding allowance length, which is greater than or equal to the sampling stroke of the sampler.

[0015] Furthermore, the transmission unit includes a first bevel gear, a first worm, a second bevel gear, a coupling, and a second worm. The deep-sea motor shaft is connected to the first worm via the coupling. The first worm meshes with the lead screw via gears. The first worm meshes with the second worm. The second worm is connected to the winding part. The first worm, the second worm, and the lead screw are rotatably connected to the fixed platform.

[0016] Furthermore, the sampler is equipped with a lead screw nut that mates with the lead screw.

[0017] Furthermore, the layered portion is a strip-shaped blade with a blade angle of 15°-20°.

[0018] Furthermore, the sealing part includes a super-dual-hydrophobic layer, a PP spunbond nonwoven fabric, a polymer breathable membrane, a PP spunbond nonwoven fabric, and a super-dual-hydrophobic layer arranged in sequence.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. This sampler, in conjunction with the drive assembly, can achieve in-situ sampling. Through the stratification section, it can complete the stratification of the sample and simultaneously perform low-disturbance filtration and storage of pore water without damaging the sample.

[0021] 2. This sampler has a compact structure. The pore water storage tank can ensure the sealing of the sampling layer during the sampling and sealing stages. In the intermediate stage, it can work with its own piston to complete the filtration and storage of pore water. With the drive component, it can complete the collection, stratification, sealing and filtration and storage of pore water in one set of processes, which is highly efficient.

[0022] 3. This sampler adopts a modular installation method, which is convenient for installation and maintenance, and can work normally in the high-pressure environment of the deep sea;

[0023] 4. During the filtration and storage of pore water, this sampler adjusts and controls the filtration pressure to avoid structural damage to the sample, ensuring high reliability. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 This is a cross-sectional view of an in-situ stratified sampler for pore water in deep-sea sediments according to the present invention.

[0026] Figure 2 This is a top view of an in-situ stratified sampler for pore water in deep-sea sediments according to the present invention;

[0027] Figure 3 This is a side view of the sampler described in this invention;

[0028] Figure 4 This is a schematic diagram of the connection structure between the inner cylinder and the porous water treatment component described in this invention;

[0029] Figure 5 As described in this invention Figure 4 A magnified view of part A;

[0030] Figure 6 As described in this invention Figure 4 A magnified view of part B;

[0031] Figure 7 This is a bottom view of the inner cylinder described in this invention;

[0032] Figure 8 This is a diagram illustrating the process of sealing the sample in layers using the sealing part described in this invention.

[0033] Figure 9 This is a diagram illustrating the displacement process of the pore water storage tank described in this invention.

[0034] Figure 10 This is a front view of the layered knife-sealed waterproof layer described in this invention;

[0035] Figure 11 As described in this invention Figure 10 Sectional view along axis AA;

[0036] Figure 12 As described in this invention Figure 11 A magnified view of part I;

[0037] Figure 13 This is a side view of the pore water storage tank described in this invention;

[0038] Figure 14 As described in this invention Figure 13 A sectional view;

[0039] Figure 15 As described in this invention Figure 14 Enlarged view of part II;

[0040] Figure 16 This refers to the motion state of the traction part as described in this invention;

[0041] Figure 17 As described in this invention Figure 16 A magnified view of a portion of the image.

[0042] 1. First connecting screw; 2. Fixing platform; 3. Single-row deep groove ball bearing; 4. First bevel gear; 5. Second connecting screw; 6. First shaft retaining ring; 7. Lead screw; 8. First worm; 9. Second bevel gear; 10. Second shaft retaining ring; 11. Bearing mounting seat; 12. Flange outer ring deep groove ball bearing; 13. Coupling; 14. Deep-sea motor; 15. Deep-sea motor retaining ring; 16. Deep-sea motor tail compartment mounting seat; 17. Third connecting screw; 18. Support rod; 19. Fourth connecting screw; 20. Worm gear support rod fixing platform; 21. Second worm; 22. Worm gear support rod; 23. Lead screw lower mounting seat; 24. Fifth connecting screw. ; Screw nut 25; Push rod 26; Sixth connecting screw 27; Sampler transmission rod 28; Seventh connecting screw 29; Top layer of sampler inner cylinder 30; Outer cylinder of sampler 31; Filter element 32; Pore water storage tank 33; Piston 34; Bottom layer of sampler inner cylinder 35; Sealing and waterproof layer 36; Layered part 37; Inner cylinder of sampler 38; Eighth connecting screw 39; Ninth connecting screw 40; Tenth connecting screw 41; Eleventh connecting screw 42; Twelfth connecting screw 43; Pulling part 44; Sealing strip 45; ePTFE polymer breathable membrane 46; PP spunbond nonwoven fabric 47; Super double-layer sprayed layer 48. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0044] It should be noted that the descriptions of "left," "right," "left side," "right side," "upper part," "lower part," "top," and "bottom" in this invention are defined based on the orientation or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the described structure must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0045] In the description of this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Referring to the accompanying drawings, this embodiment describes an in-situ stratified sampler for pore water in deep-sea sediments, comprising:

[0047] The sampler is equipped with a sampling chamber, which has an opening on the side near the sediment. The sampler is specifically configured as a sampling tube, which is divided into an inner tube and an outer tube. The inner tube 38 of the sampler is connected to the bottom layer 35 and the top layer 30 of the inner tube by the twelfth connecting screw 43. Then, the upper end face of the outer tube 31 of the sampler is connected to the top layer 30 of the inner tube by bolts, and the lower end face is connected to the bottom layer 35 of the inner tube by the stepped shaft of the outer tube 31 itself. This completes the initial assembly of the deep-sea sediment sampler.

[0048] A drive assembly, connected to the sampler, is used to drive the sampler to collect sediment from the opening into the sampling chamber. The drive assembly is coupled to the pulling part 44, so that when the drive assembly drives the sampler to move relative to the sediment layer, it can synchronously drive the pulling part 44 to move. During the sampling process, since the pulling part 44 has reserved winding length, the pulling part 44 is continuously tightened during the sampling process. When the sampling is completed, the pulling part 44 is tightened, thereby driving the layering part 37 to move radially along the inside of the sampling chamber to complete the layering and cutting process of the internal sample.

[0049] The layering section 37 is provided in several parts and spaced apart along the axial direction of the sampling cavity. Each layering section 37 is slidably connected to the sampling cavity. One end of the layering section 37 is connected to the pulling part 44 and the other end is connected to the sealing part. It is used to separate the sediment in the sampling cavity into several layers under the traction of the pulling part 44. The sealing part is used to unfold after being pulled by the layering section 37 to separate and seal the adjacent two layers of sediment that have been cut apart. The sampling process, the sample layering process, and the sealing process after layering can be completed through the action of a driving component. At the same time, it can help the pore water treatment component to complete the pore water extraction of the corresponding layer of sediment and the final sealing process. No additional driving structure is required. The structure is simple and efficient, and it solves the technical problems mentioned in the background art.

[0050] The pore water treatment component is provided in several parts and is slidably mounted on the sampler. It is used to couple with the stratification section 37 and then communicate with the stratified sediments. After filtering the water in the corresponding sediment layer, it completes the sealing of the corresponding sediment layer and the filtered water.

[0051] In this embodiment, the pore water treatment assembly includes a filter element 32, a pore water storage chamber 33, and a piston 34. The filter element 32 is disposed on the side of the pore water storage chamber 33 near the sampler, and the piston 34 is slidably disposed inside the pore water storage chamber 33. The piston divides the pore water storage chamber 33 into two chambers, one of which is connected to the filter element 32, and the other chamber has adjustable pressure. The filter element 32 is used to filter water entering one chamber when it is connected to the corresponding layer of sediment. The outer wall of the pore water storage chamber 33 is used to seal the corresponding layer of sediment when the filter element 32 is misaligned with the corresponding layer of sediment.

[0052] Specifically, one side of the pore water storage chamber 33 is placed in a groove on the side wall of the sampler inner cylinder 38 and housed within the outer cylinder. The arc-shaped side is fitted with the sampler outer cylinder 31 with a clearance, and the friction provided by the arc-shaped surface of the silicone-cast pore water storage chamber 33 is sufficient to counteract the downward force of gravity. The piston 34 is placed inside the pore water storage chamber 33, and the filter element 32 is cast onto the side of the pore water storage chamber 33, specifically the side closest to the sampler inner cylinder 38. The main body of the pore water storage chamber 33 is made of a mixture of acrylic sheet and silicone. The bottom and middle supporting frames of the storage chamber are also made of acrylic sheet. Figure 14 The black portion is made of silicone, while the rest is cast from silicone. Inside the water storage tank is a piston 34. A silicone-sealed hole on the side of the water storage tank allows for pressurization. The silicone surface inside the water storage tank has a hole formed by casting with the filter element. The pore water storage tank 33 moves vertically, utilizing the filter element's holes to complete the filtration and sealing of the pore water. The filter element 32 mainly consists of three layers of filter mesh: an outer layer of stainless steel perforated plate, a middle layer of polymer membrane mesh, and an inner layer of stainless steel fiber sintered felt.

[0053] In this embodiment, the other cavity is pre-filled with gas at a certain pressure and then sealed. Specifically, the other cavity is the space below the piston 34, and high-pressure gas can be injected through the inflation pipe of the porous water storage tank 33 to adjust the pressure difference. The inflation pipe is sealed with silicone to ensure the airtightness of the porous water storage tank 33.

[0054] In this embodiment, the drive assembly includes a lead screw 7, a deep-sea motor 14, a transmission part, and a winding part. The shaft of the deep-sea motor 14 is connected to the lead screw 7 and the winding part respectively through the transmission part. The lead screw 7 is connected to the sampler and is used to drive the sampler to move along the axial direction of the lead screw 7. The winding part is used to wind up or release the pulling part 44.

[0055] In this embodiment, the pulling part 44 has a winding allowance, which is greater than or equal to the sampling stroke of the sampler. Specifically, the pulling part 44 is a steel wire rope of a certain length, with one end fixed to the winding part and the other end having multiple branches. Each branch is connected to a layering cutter within the rope. For corner positions, a corresponding corner transition limit structure can be provided to help the steel wire rope turn and limit its movement path. The purpose of setting the winding allowance is to prevent the layering part 37 from moving during sampling, ensuring that the sampler operates strictly in the sequence of sampling, layering, layer sealing, pore water drainage, and final sealing.

[0056] In this embodiment, the transmission unit includes a first bevel gear 4, a first worm 8, a second bevel gear 9, a coupling 13, and a second worm 21. The shaft of the deep-sea motor 14 is connected to the first worm 8 via the coupling 13. The first worm 8 meshes with the lead screw 7 via gears. The first worm 8 meshes with the worm gear on the second worm 21. The second worm 21 is connected to the winding part. The first worm 8, the second worm 21, and the lead screw 7 are rotatably connected to the fixed platform 2. Both the first worm 8 and the second worm 21 are connected to the fixed platform 2 via bearing seats, which are fixedly connected to the fixed platform 2 via a tenth connecting screw 41.

[0057] In this embodiment, the sampler is provided with a lead screw nut 25 that cooperates with the lead screw 7.

[0058] Specifically, firstly, the four support rods 18 are fixed to the grooves under the fixed platform 2 using the first connecting screw 1. Then, the deep-sea motor fixing ring 15, the worm gear support rod fixing platform 20, and the bearing fixing seat 11 are fixed to the fixed platform 2 using the fourth connecting screw 19. Next, the deep-sea motor 14 is placed on the deep-sea motor fixing ring 15, and the upper and lower halves of the deep-sea motor fixing ring 15 are connected using the ninth connecting screw 40 to complete the fixing of the deep-sea motor 14. The tail section of the deep-sea motor 14 is mounted on the fixed platform 2 using the deep-sea motor tail section fixing seat 16. The deep-sea motor tail section fixing seat 16 is specifically fixed using the third connecting screw 17.

[0059] Then, the second worm 21 is fixed by the elastic retaining ring 6 on the first shaft and the keyway of the worm gear support rod 22. The worm gear support rod 22 is placed between the two worm gear support rod fixing platforms 20 to complete the placement of the second worm 21. The deep-sea motor 14 is connected to the first worm 8 by the coupling 13. Then, the flange outer ring deep groove ball bearing 12 is fixed to the first worm 8 by the elastic retaining ring 6 on the first shaft and the keyway of the first worm 8, in conjunction with the bearing fixing seat 11. The coupling 13 is a DFC aluminum alloy plum blossom type clamping coupling.

[0060] Then, the second bevel gear 9 is fixed by the elastic retaining ring 10 of the second shaft and the keyway of the first worm 8, and the eleventh connecting screw 42 is used to make the bevel gear and the first worm 8 achieve a clearance fit to further fix the second bevel gear 9, so that it rotates synchronously with the first worm 8. The second bevel gear 9 will drive the first bevel gear 4 to rotate together. The first bevel gear 4 is first initially fixed by the elastic retaining ring 6 of the first shaft and the keyway of the lead screw 7, and then further fixed by the second connecting screw 5, so that it rotates synchronously with the lead screw 7.

[0061] The lead screw 7 is fixed to the position of the single-row deep groove ball bearing 3 on the lead screw 7 shaft by the elastic retaining ring 6 on the first shaft. The single-row deep groove ball bearing 3 is fixed in the groove of the fixed platform 2, thus completing the initial fixation of the lead screw 7. Then, the lower fixing seat 23 of the lead screw is installed on the fixed platform 2 by the eighth connecting screw 39, and the lead screw 7 is further fixed by the stepped shaft of the lead screw 7. The rotation of the lead screw 7 will drive the lead screw nut 25 to rotate downward along the thread of the lead screw 7. Since the push rod 26 is fixed to the lead screw nut 25 by the fifth connecting screw 24, the push rod 26 will also be displaced vertically with the rotation of the lead screw 7.

[0062] The sampler drive rod 28 is connected to the push rod 26 via the sixth connecting screw 27, and the sampler drive rod 28 is connected to the sampler via the seventh connecting screw 29. Thus, the deep-sea sediment sampler can be driven downward to collect deep-sea sediment columns by the rotation of the lead screw 7.

[0063] In this embodiment, the layering part 37 is a strip-shaped blade with a blade angle of 15°-20°. Specifically, the layering part 37 is a layering blade, slidably placed on a slide rail of the sampler inner cylinder 38. The specific structure of the slide rail and the sliding cooperation between the two are reasonably selected according to actual requirements. One side of the sealing and waterproof layer 36 is tightly connected to the special adhesive and the layering blade 37 via a pulling part 44, while the other side is placed on a protrusion of the sampler inner cylinder 38. The special adhesive must meet the requirements of the underwater operating environment and is reasonably selected according to actual conditions. One end of the pulling part 44 is fixed to the layering blade 37, and the other end is fixed to the worm gear support rod 22, with a certain length reserved. The stratification blade moves along the slide of the sampling chamber under the traction of a steel wire rope to cut the sediment column. Its main body is made of high carbon alloy, with a single-sided cutting angle of ≤12° and an overall cutting angle of about 15°. The blade surface creates an array of micron-level protrusions or pits to form an isolation air cushion, which can significantly reduce the effective contact area. The surface of the blade surface has a metallic glass (TFMG) coating to reduce the adhesion area.

[0064] In this embodiment, the sealing waterproof layer 36 is connected to the layering knife by iron wire and special adhesive, and is composed of multiple layers of different materials. The first layer is a super double-layer spray layer 48, the second layer is PP spunbond nonwoven fabric 47, the middle layer is ePTFE polymer breathable membrane 46, the fourth layer is PP spunbond nonwoven fabric 47, and the fifth layer is the super double-layer spray layer 48. Waterproof sealing strips 45 are attached to both sides. The waterproof sealing strips are used to ensure a reliable seal between the sealing waterproof layer and the inner cylinder during the sliding process and the final sealing process.

[0065] The super-dual-hydrophobic spray layer 48 is formed by repeatedly spraying a suspension of silica aerogel particles (F-SiO2), fluorinated compounds polyvinylidene fluoride-hexafluoropropylene, and FAS onto the surface of PP spunbond nonwoven fabric 47. The super-dual-hydrophobic surface with a WCA greater than 170° and an OCA of approximately 158° can effectively prevent water-containing deposits from adhering to the sealing and waterproof layer. The PP spunbond nonwoven fabric 47 is made using a melt spinning process, with a fiber density of over 3000 fibers per square centimeter and a tensile strength of 50 N / cm², which can effectively prevent the sealing and waterproof layer from breaking. The ePTFE polymer breathable membrane 46 forms a three-dimensional network of pores through a node-fiber structure, and its micropore diameter can be precisely controlled within 0.01-5 micrometers, which can effectively prevent the flow of pore water.

[0066] Low-disturbance cutting should cleanly separate the sediment on both sides, avoiding compression or shear deformation of areas outside the cutting surface. If the blade is not sharp enough or advances too quickly, the blade surface will compress the sediment in front, causing irreversible plastic flow and shear failure, resulting in severe disturbance. Therefore, the design of the blade and the traction force and speed of the wire rope are both important. Single-sided blades, due to their asymmetrical design, exert minimal lateral compression on the preserved sediment column, making them more suitable for cutting deep-sea sediment columns.

[0067] Regarding the design of the cutting edge, the cutting angle β should first consider both reducing compression and preventing edge roll. Treating the cutting edge tip as a wedge, the pressure it needs to overcome to penetrate the deposit, under a relatively small coefficient of friction μ, is related to... , and It is directly proportional. Therefore, a sufficiently small β, typically ≤20°, must be used to ensure that the intrusion pressure is below its undrained shear strength, preventing large-scale plastic extrusion before the cutting begins.

[0068] Treating a single-sided cutting edge as a cantilever beam, the root bears the maximum bending stress. The smaller the cutting edge angle β, the sharper the cutting tip, and the more significant the stress concentration effect. To ensure the cutting edge does not chip or break when cutting gravelly sediments, strength conditions must be met. K is the stress concentration factor (>1), P is the tip pressure, and η is the safety factor. For tool steel or cemented carbide, the minimum cutting edge angle for reliable operation in deep-sea environments is typically above 12°-15°. Therefore, its optimal range should be 15°-20°.

[0069] Secondly, the blade should be made of a material with high hardness and low surface energy, and its friction and adhesion formula is as follows: And by formula Therefore, a thin and long blade should be selected.

[0070] Specifically regarding the filtration of pore water: at the sediment contact surface, there exists pore water that overcomes capillary forces. Critical pressure at which flow begins Its formula is: ;

[0071] Surface tension of pore water The contact angle between water and the filter membrane and sediment particles. : is the effective radius of the sediment pore throat or filter membrane pore size, if the effective stress If the increase in pressure exceeds the undrained shear strength of the sediment at that point, shear failure will occur in the sediment structure. Therefore, we need to estimate the upper limit of the safe pressure difference based on the shear strength to reduce the damage to the pore structure of deep-sea sediments caused by the effective stress increment.

[0072] The inequality for the upper limit of safe differential pressure is: ;

[0073] The undrained shear strength of sediments is measured in Pa. This is the most critical geological parameter, depending on the sediment type, density, and other factors. Safety factor. To ensure absolute safety, it is usually taken as... =1.5-3.

[0074] The maximum safe limit for differential pressure; therefore, the range of differential pressure values ​​is: ;

[0075] The pore water filtration time, i.e., the shutdown time of the deep-sea motor, is mainly determined by the target pore water collection volume and the properties of the sediment, as shown below: or ;

[0076] in: The instantaneous flow rate at time t. The initial flow rate can be estimated using Darcy's law. Attenuation coefficient The cumulative water volume collected up to time t can be used to calculate the time it takes for the motor to stop pumping pore water.

[0077] In use, the controller program is set, and the sampler is taken to the designated location by the submersible for deployment. At this time, the deep-sea motor 14 drives the first worm 8 to rotate through the DFC aluminum alloy plum blossom clamping coupling 13. The second bevel gear 9 at the end of the first worm 8 is fixed by the keyway on the first worm 8 and the shaft elastic retaining ring and can only rotate with the first worm 8, thereby driving the first bevel gear 4 and the trapezoidal lead screw 7 to rotate together. The rotation of the trapezoidal lead screw 7 will drive the lead screw nut 25 to rotate downward along the lead screw thread. The downward movement of the lead screw nut 25 will drive the push rod 26 and the sampler transmission rod 28 to move downward, thereby making the sampler move downward at a uniform speed and smoothly to complete the sampling work. Due to the different rotation speeds of the worm gear and worm, the downward speed of the sampler is not equal to the sliding speed of the stratification knife. In addition, the steel wire rope connecting the stratification knife will reserve a certain length according to the calculation results, so that the winding part of the worm gear support rod 22 will not drive the stratification knife to move before winding this section of steel wire rope.

[0078] When the sampler reaches the designated depth and completes the predetermined sampling work, the winding section immediately winds up the reserved length and continues to wind the remaining wire rope. At this time, the layering blades and sealing parts between different layers move synchronously along the slide of the sampler's inner cylinder under the traction of the wire rope to complete the layered sealing of the sediment column. When the layering blades have finished cutting the sediment column, that is, when the layering blades and the waterproof sealing layer reach the end of the slide of the sampler's inner cylinder, the second worm gear 21 continues to rotate, and each layering blade will be pulled away from the slide of the sampler's inner cylinder under the traction of the wire rope and move upward along the cylinder wall of the sampler's inner cylinder 38. When the blades of each layering blade simultaneously hit the lower acrylic plate of their respective pore water storage tank 33, they will drive the pore water storage tank to move upward. During the movement, when the filter element 32 connects with the opening provided on the side wall of the inner cylinder, the movement of the piston 34 completes the extraction of pore water. Since the pressure in the lower cavity of the piston 34 is adjustable, the extraction pressure is adjustable to avoid damage to the sample. After the pore water is filtered, the pore water storage tank 33 continues to move, closing the aforementioned opening and completing the sealing process.

[0079] The sensors, controllers, and control algorithms mentioned above are all existing technologies and will not be elaborated upon.

[0080] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A deep-sea sediment pore water in-situ stratified sampler, characterized in that, include: A sampler is provided with a sampling chamber, and the sampling chamber has an opening on the side near the sediment. A drive assembly, connected to the sampler, is used to drive the sampler to collect sediment from the opening into the sampling chamber, wherein the drive assembly is coupled to the pulling part (44); The layered section (37) is provided in a plurality of such sections and spaced apart along the axial direction of the sampling cavity. Each layered section (37) is slidably connected to the sampling cavity. One end of the layered section (37) is connected to the pulling section (44) and the other end is connected to the sealing section. It is used to separate the sediment in the sampling cavity into several layers under the traction of the pulling section (44). The sealing section is used to unfold after being pulled by the layered section (37) to separate and seal the two adjacent layers of sediment that have been cut apart. The pore water treatment component is provided with several units that are slidably mounted on the sampler. It is used to couple with the stratification section (37) and then communicate with the stratified sediments. After filtering the water in the corresponding sediment layer, it completes the sealing of the corresponding sediment layer and the filtered water.

2. The in-situ stratified sampler for pore water in deep-sea sediments according to claim 1, characterized in that: The pore water treatment assembly includes a filter element (32), a pore water storage chamber (33), and a piston (34). The pore water storage chamber (33) has a filter element (32) on the side near the sampler, and a piston (34) is slidably installed inside. The piston divides the pore water storage chamber (33) into two chambers, one of which is connected to the filter element (32), and the other chamber has adjustable pressure. The filter element (32) is used to filter water entering one chamber when it is connected to the corresponding layer of sediment. The outer wall of the pore water storage chamber (33) is used to seal the corresponding layer of sediment when the filter element (32) is misaligned with the corresponding layer of sediment.

3. The in-situ stratified sampler for pore water in deep-sea sediments according to claim 2, characterized in that: The other cavity is pre-filled with gas at a certain pressure and then sealed.

4. The in-situ stratified sampler for pore water in deep-sea sediments according to claim 1, characterized in that: The sampler includes an inner cylinder and an outer cylinder arranged coaxially. The sampling chamber is disposed inside the inner cylinder, and the pore water treatment component is slidably disposed on the outer wall of the inner cylinder and housed inside the outer cylinder.

5. A deep-sea sediment pore water in-situ stratification sampler according to any one of claims 1-4, characterized in that: The drive assembly includes a lead screw (7), a deep-sea motor (14), a transmission part, and a winding part. The shaft of the deep-sea motor (14) is connected to the lead screw (7) and the winding part respectively through the transmission part. The lead screw (7) is connected to the sampler and is used to drive the sampler to move along the axial direction of the lead screw (7). The winding part is used to wind up or release the pulling part (44).

6. The in-situ stratified sampler for pore water in deep-sea sediments according to claim 5, characterized in that: The pulling part (44) has a winding reserve length, which is greater than or equal to the sampling stroke of the sampler.

7. The in-situ stratified sampler for pore water in deep-sea sediments according to claim 5, characterized in that: The transmission unit includes a first bevel gear (4), a first worm (8), a second bevel gear (9), a coupling (13), and a second worm (21). The shaft of the deep-sea motor (14) is connected to the first worm (8) through the coupling (13). The first worm (8) meshes with the lead screw (7) through gears. The first worm (8) meshes with the second worm (21). The second worm (21) is connected to the winding part. The first worm (8), the second worm (21), and the lead screw (7) are rotatably connected to the fixed platform (2).

8. The in-situ stratified sampler for pore water in deep-sea sediments according to claim 5, characterized in that: The sampler is provided with a lead screw nut (25) that cooperates with the lead screw (7).

9. A deep-sea sediment pore water in-situ stratification sampler according to claim 1, 2, 3, 4, 6, 7 or 8, characterized in that: The layered part (37) is a strip-shaped blade with a blade angle of 15°-20°.

10. A deep-sea sediment pore water in-situ stratification sampler according to claim 1, 2, 3, 4, 6, 7 or 8, characterized in that: The sealing part includes a super-dual-hydrophobic layer, a PP spunbond nonwoven fabric, a polymer breathable membrane, a PP spunbond nonwoven fabric, and a super-dual-hydrophobic layer arranged in sequence.

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