A deep aquifer water quality stratified sampling device and method

Abstract

The application relates to the technical field of water quality sampling equipment, in particular to a deep aquifer water quality layered sampling device and method, which comprises an outer shell, an inner sleeve, a pressure introduction cavity, a compression spring and a plurality of layered sampling cavities arranged along the axial direction at intervals. The inner sleeve moves along the axial direction under the action of hydrostatic pressure, so that the aligned sampling windows on the layered sampling cavities are sequentially aligned and communicated with the shell communication windows on the outer shell, and the water bodies in different depth aquifers are sequentially sampled. The application completes the discrete layer sampling through the pressure-driven self-addressing and staggered window structure, does not need additional depth positioning equipment, reduces the equipment cost, improves the convenience and layer position corresponding precision of the device, reduces the risk of liquid mixing, and improves the layered sampling precision and sample representativeness.

Description

Technical Field

[0001] This invention relates to the field of water quality sampling equipment technology, and in particular to a device and method for stratified sampling of water quality in deep aquifers. Background Technology

[0002] Deep aquifer stratified sampling technology is mainly used to obtain in-situ samples or monitoring information of groundwater at different burial depths to analyze the differences in water chemistry, pollution migration patterns, and water body evolution characteristics between aquifers. Existing technologies commonly involve deploying sampling pipes, stratified samplers, or multi-point monitoring devices within the borehole, and collecting groundwater at the target depth through mechanical opening, valve-controlled conduction, or pump suction. This type of technology typically relies on downhole positioning, depth marking, external actuation, or electronic measurement components to determine the sampling layer, and combines this with sealed structures, one-way valves, or isolation chambers to achieve stratified sampling, thereby meeting the needs of water quality analysis at different depths.

[0003] However, existing deep aquifer stratified sampling technologies still have shortcomings. First, sampling layer identification typically relies on additional depth measurement, positioning, or control components to obtain depth and data collection, which is not only structurally complex but also highly susceptible to electromagnetic interference or cable breakage. Second, during depth sampling, the equipment itself is significantly affected by borehole deviation, lowering errors, and environmental disturbances, leading to inaccurate layer correspondence (i.e., the measured depth obtained when tilted does not match the actual sampling depth). Additionally, monitoring components are easily affected by external mud or obstruction, resulting in inaccurate detection data. Finally, traditional stratified sampling structures are prone to inaccurate opening misalignment and interference between water bodies at different depths. Water from the previous layer may move with the structure and enter the sampling process of the next layer, causing sample contamination or depth assignment deviations, thereby reducing the accuracy and repeatability of the sampling results. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a device and method for stratified sampling of water quality in deep aquifers.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A deep aquifer water quality stratification sampling device includes a sampling kit for drilling down a borehole. The sampling kit includes an outer shell and an inner sleeve movably disposed within the outer shell. A pressure inlet cavity is provided at the lower end of the outer shell. A pressure guide port communicating with an external aquifer is provided at the bottom of the pressure inlet cavity. A compression spring is provided at the upper part of the pressure inlet cavity. The upper end of the inner sleeve is connected to the compression spring to move axially relative to the outer shell under hydrostatic pressure. A spring preload adjustment component is provided on the compression spring to change the initial compression amount of the compression spring, thereby corresponding to the hydrostatic pressure threshold of different depth ranges. The inner sleeve has multiple layered sampling chambers spaced axially in its inner cavity. Each layered sampling chamber has an alignment sampling window on its side wall. The outer shell has multiple corresponding shell conduction windows on its axial region corresponding to the alignment sampling windows. The outer periphery of the inner sleeve is in sliding sealing fit with the inner wall of the pressure inlet chamber. The sampling kit is configured such that, under normal conditions, the alignment sampling window and the shell conductive window are in an axially misaligned and closed state. When the inner sleeve undergoes axial displacement under hydrostatic pressure, multiple alignment sampling windows sequentially align and connect with the corresponding multiple shell conductive windows, and the alignment and connection sequence is from bottom to top, so that the water in the external aquifer enters the corresponding stratified sampling chamber to complete stratified sampling.

[0006] Furthermore, multiple shell-connecting windows are equally spaced along the axial direction, and multiple alignment sampling windows are equally spaced along the axial direction. The axial distance between two adjacent shell-connecting windows is greater than the axial distance between two adjacent alignment sampling windows. The multiple alignment sampling windows are arranged in a staggered, circumferentially graduated pattern, with different opening azimuth angles between adjacent alignment sampling windows, so that each alignment sampling window faces a different circumferential orientation in the top view. This staggered arrangement allows each alignment sampling window to independently align with different shell-connecting windows on the outer shell during the axial movement of the inner sleeve. This ensures that the alignment sampling windows only connect at their corresponding depths, thus avoiding repeated connections that could cause cross-contamination. In addition, the staggered, circumferentially graduated arrangement of the alignment sampling windows also prevents the overall center of gravity from concentrating on one side of the outer shell, thus avoiding problems such as center of gravity shift or insufficient stability. Due to the different opening azimuth angles, water entering the shell can also form a dispersed inflow in the circumferential direction, which helps reduce local jet impact and turbulent disturbances.

[0007] Furthermore, a water-blocking valve is provided at the bottom of the inner sleeve, and a water-proof rubber ring adapted to the inner wall of the pressure inlet cavity is sleeved around the periphery of the water-blocking valve. The water-blocking valve is mainly used to transmit pressure to the water entering through the pressure inlet, so that the external hydrostatic pressure can directly act on the water-blocking valve, thereby controlling the corresponding relationship between the axial displacement and depth change of the inner sleeve.

[0008] Furthermore, the sampling kit also includes a locking assembly for locking the inner sleeve. This locking assembly comprises a locking chuck at the top of the inner sleeve and a wedge-shaped locking member on the inner wall of the pressure inlet chamber. The locking assembly is configured such that when the compression spring is compressed to its extreme value, the locking chuck pushes the wedge-shaped locking member inward along the guide slope of the wedge-shaped locking member. After the locking chuck passes the wedge-shaped locking member, the wedge-shaped locking member is reset and extended under the action of the elastic component, and is positioned below the locking chuck, thus limiting and locking the inner sleeve's fall. When the inner sleeve moves to the preset end point under hydrostatic pressure, its position is maintained at its extreme value by a mechanical limiting structure, preventing the inner sleeve from moving downward relative to the outer shell due to a decrease in external hydrostatic pressure during subsequent retraction. During the downward movement of the inner sleeve relative to the outer shell, each layer of sampling chamber will reconnect with the external water body, which could lead to sample cross-contamination and consequently reduce sample accuracy.

[0009] Furthermore, the outer casing corresponding to the wedge-shaped locking member is provided with an operating port extending into the pressure inlet cavity. An elastic component is disposed within the operating port, which pushes the wedge-shaped locking member towards the pressure inlet cavity. The lower end face of the wedge-shaped locking member forms a guide slope for the locking chuck to push against it, so that when the locking chuck moves upward, it presses the wedge-shaped locking member into the operating port. After the locking chuck passes, the wedge-shaped locking member re-enters the pressure inlet cavity under the action of the elastic component, thereby forming a downward stop on the locking chuck. A first limiting block is disposed within the operating port, and a limiting ring is disposed on the wedge-shaped locking member. The elastic component is sleeved on the wedge-shaped locking member and located between the first limiting block and the limiting ring. Because the lower end face of the wedge-shaped locking member is set as a guide slope, when the locking chuck moves upward and contacts the slope, the wedge-shaped locking member will retract radially along the operating port under the pushing force of the slope. When the locking chuck passes the wedge-shaped locking piece, the elastic component loses the external force and elastically recovers, pushing the wedge-shaped locking piece back to its original position, causing it to re-enter the pressure inlet chamber and be positioned below the locking chuck, forming a support point to prevent the wedge-shaped locking piece from falling back.

[0010] Furthermore, the pressure guide port is located at the bottom center of the outer casing, and a sand filter cover is provided around the pressure guide port to reduce the impact of mud and sand blockage and local turbulence on hydrostatic pressure transmission. The sand filter cover is used to prevent fine particles of mud, sand, suspended matter, and debris from directly entering the pressure inlet chamber in the complex environment of deep aquifers, avoiding pressure transmission efficiency due to sediment blockage at the pressure guide port. While weakening water pressure transmission, the sand filter cover performs primary filtration of the incoming water, reducing pressure fluctuations caused by blockage and local eddies, making the pressure state within the pressure inlet chamber more stable. Simultaneously, the pressure guide port's central location at the bottom facilitates the direct acquisition of a relatively uniform hydrostatic pressure signal from the bottom area, reducing interference from lateral disturbances and bias pressure on the sampling operation, thereby improving the stability of depth identification and stratified conduction.

[0011] Furthermore, an anti-rotation guide structure is provided between the outer shell and the inner sleeve. This anti-rotation guide structure includes a guide pin disposed on the outer wall of the inner sleeve and an anti-rotation guide groove disposed on the inner wall of the pressure inlet cavity. The guide pin is slidably disposed within the groove of the anti-rotation guide groove. The anti-rotation guide structure is used to restrict the circumferential rotation of the inner sleeve during axial reciprocating motion, ensuring that the inner sleeve always maintains a preset angle and posture, thereby guaranteeing that each alignment sampling window is aligned with the corresponding shell conduction window in a preset direction.

[0012] Furthermore, the upper part of the pressure inlet cavity is provided with a spring seat for the compression spring to abut against, and the spring preload adjustment component is either an adjusting nut or a clamping sleeve. The spring preload adjustment component can calibrate and fine-tune the initial force state of the compression spring according to different drilling depths, different aquifer water pressure conditions, and different sampling layers. By adjusting the initial compression amount, the pressure threshold at which the inner casing begins to generate effective displacement can be changed, so that a more accurate pressure correspondence is formed between the sampling action and the target depth, avoiding threshold deviation caused by changes in groundwater density, local temperature differences, or wellbore disturbance.

[0013] A sampling method using a sampling device includes the following steps: S1: Based on the preset depth range of the target borehole, the initial compression amount of the compression spring is preset so that each layered sampling chamber corresponds to the preset depth pressure threshold. S2: The outer casing is lowered into the target borehole by the lifting mechanism. When the outer casing descends and reaches the aquifer, the water enters the pressure inlet chamber through the pressure guide port and exerts a pressure difference on the inner casing. S3: During the continuous descent of the outer casing, the inner sleeve moves axially upward relative to the outer casing under the action of pressure difference, overcoming the elastic force of the compression spring. S4: When the bottommost alignment sampling window is aligned with the bottommost shell conduction window, the alignment sampling window and the shell conduction window change from misaligned and closed to conduction, and the water body of the external aquifer enters the layered sampling cavity to obtain the sampling sample corresponding to the precise depth. S5: The outer shell continues to descend, causing the next layered sampling cavity to form a new alignment connection with the corresponding shell conduction window in sequence. At the same time, the alignment sampling window of the previous layered sampling cavity and the shell conduction window are misaligned and closed again, thus completing continuous layered sampling of multiple depth intervals. S6: When the inner sleeve moves upward to the preset limit stroke, the locking chuck pushes the wedge-shaped locking member inward along the guide slope of the wedge-shaped locking member. After the locking chuck passes the wedge-shaped locking member, the wedge-shaped locking member is reset and extended under the action of the elastic component and is locked below the locking chuck to form a back-fall limit lock for the inner sleeve and ensure that the layered sampling cavity that has completed sampling is no longer connected to the outside. S7: After sampling is completed, the outer shell is lifted upward by the lifting mechanism, and the water samples collected and sealed in each layer of sampling chamber remain in an independent state.

[0014] Furthermore, in step S1 above, the preset compression amount of the compression spring is calibrated according to the correspondence between depth, hydrostatic pressure, and axial displacement, ensuring that the inner sleeve can only stop at the corresponding discrete sampling points at different depths, thus preventing liquid cross-contamination between adjacent layered sampling chambers. By pre-calculating the hydrostatic pressure corresponding to different depths, the compression amount of the compression spring can be set to several discrete levels, ensuring that the inner sleeve only undergoes a corresponding displacement when a specific pressure range is reached. This ensures that the alignment sampling window and the shell conduction window only form a short-term connection at a preset layer. The continuously changing depth signal is converted into a mechanically executable layering trigger condition, avoiding window misalignment or liquid cross-contamination problems caused by excessive displacement.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention drives the axial displacement of the inner sleeve by hydrostatic pressure and combines it with a staggered window-type layered sampling structure, so that the sampling cavities corresponding to different depths can be sequentially connected under a preset pressure threshold, thereby realizing automatic addressing of the sampling layer, reducing the dependence on external depth sounding and complex positioning equipment, which not only reduces equipment and maintenance costs, but also improves the convenience of deployment and the accuracy of layer correspondence. 2. This invention, through the discrete matching design of the sampling window and the shell conduction window, combined with the anti-rotation guide structure and the spring pre-tightening adjustment structure, makes the conduction action during the sampling process stable and repeatable, effectively avoiding accidental opening and cross-contamination, and ensuring the independence and representativeness of water samples at different depths. 3. By setting the sampling chamber to an axially discrete distribution structure and retrieving and sealing the water samples from each layer after sampling, this invention can reduce the interference of residual water on subsequent sampling and improve the reliability, operability and practical application value of multi-layer continuous sampling. Attached Figure Description

[0016] Figure 1 This is a schematic axial cross-sectional view of the present invention; Figure 2 yes Figure 1 Enlarged view of point A in the middle; Figure 3 This is a three-dimensional structural schematic diagram of the present invention; Figure 4 It is a top sectional view of the outer shell and inner sleeve; Figure 5 This is a plan view of Embodiment 3; Figure 6 This is a plan view of Embodiment 4; Figure 7 This is a plan view of Example 5; Figure labels: 1-Outer shell, 2-Inner sleeve, 3-Pressure inlet chamber, 4-Pressure guide port, 5-Compression spring, 6-Layered sampling chamber, 7-Alignment sampling window, 8-Shell conduction window, 9-Water baffle plate, 10-Locking chuck, 11-Wedge lock, 12-Elastic component, 13-Operating port, 14-Sand filter cover, 15-Spring preload adjustment component. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0018] Example 1, as Figures 1-4 As shown, this invention discloses a deep aquifer water quality stratification sampling device, including a sampling kit for drilling down a borehole. The sampling kit includes an outer shell 1 and an inner sleeve 2 movably disposed within the outer shell 1. A pressure inlet cavity 3 is provided at the lower end of the outer shell 1. A pressure guide port 4 communicating with an external aquifer is provided at the bottom of the pressure inlet cavity 3. A compression spring 5 is provided at the upper part of the pressure inlet cavity 3. The upper end of the inner sleeve 2 is connected to the compression spring 5 so as to move axially relative to the outer shell 1 under the action of hydrostatic pressure. A spring preload adjustment component 15 is provided on the compression spring 5 to change the initial compression amount of the compression spring 5, thereby corresponding to the hydrostatic pressure threshold of different depth ranges.

[0019] The inner sleeve 2 has multiple layered sampling chambers 6 spaced axially along its inner cavity. Each layered sampling chamber 6 has an alignment sampling window 7 on its sidewall. The outer shell 1 has multiple corresponding shell conduction windows 8 on the axial region of the alignment sampling window 7. The outer periphery of the inner sleeve 2 slides and seals against the inner wall of the pressure inlet cavity 3. A sliding sealing ring is provided between the outer periphery of the inner sleeve 2 and the inner wall of the pressure inlet cavity 3. The sliding sealing ring is fitted onto the outer periphery of the inner sleeve 2, and its outer periphery slides and seals against the inner wall of the pressure inlet cavity 3 to form a dynamic seal for the pressure inlet cavity 3 during axial movement of the inner sleeve 2. Preferably, the sliding sealing ring is a polytetrafluoroethylene (PTFE) sliding sealing ring, a Y-shaped sealing ring, or a lip sealing ring.

[0020] The sampling kit is configured such that, under normal conditions, the alignment sampling window 7 and the shell conductive window 8 are in an axially misaligned and closed state. When the inner sleeve 2 undergoes axial displacement under hydrostatic pressure, multiple alignment sampling windows 7 are sequentially aligned and connected with the corresponding multiple shell conductive windows 8, and the alignment and connection sequence is from bottom to top, so that the water in the external aquifer enters the corresponding stratified sampling chamber 6 to complete stratified sampling.

[0021] Multiple shell-connecting windows 8 are equally spaced along the axial direction, and multiple alignment sampling windows 7 are equally spaced along the axial direction. The axial distance between two adjacent shell-connecting windows 8 is greater than the axial distance between two adjacent alignment sampling windows 7. The multiple alignment sampling windows 7 are arranged in a staggered, circumferentially spaced pattern, with different opening azimuth angles between adjacent alignment sampling windows 7, so that each alignment sampling window 7 faces a different circumferential orientation in the top view. Specifically, the staggered arrangement ensures that each alignment sampling window 7 forms an independent alignment relationship with different shell-connecting windows 8 on the outer shell 1 during the axial movement of the inner sleeve 2. This ensures that the alignment sampling windows 7 only conduct at the corresponding depth, thus avoiding repeated conduction that could cause cross-contamination. Furthermore, the staggered, circumferentially spaced arrangement of the alignment sampling windows 7 also prevents the overall center of gravity from concentrating on one side of the outer shell 1, thus avoiding problems such as center of gravity shift or insufficient stability. Because the azimuth angles of each opening are different, the water can form a dispersed inflow in the circumferential direction when it enters, which helps to reduce local jet impact and turbulent disturbance, thereby improving the smoothness of the sampling process and the representativeness of the stratified samples.

[0022] In other words, taking three layered sampling cavities 6 as an example, if the axial distance between two adjacent housing conductive windows 8 is A, and the axial distance between the aligned sampling windows 7 is B, then A>B, and 2B>A, i.e., A>B>0.5A. Assuming there are four layered sampling cavities 6, then A>B, and 3B>2A, i.e., A>B>2A / 3. Similarly, when there are n layered sampling cavities 6, A>B>(n-2)A / (n-1). Here, n is the number of layered sampling cavities 6, and the axial opening length of any housing conductive window 8 and any aligned sampling window 7 is less than AB to avoid overlapping conduction between adjacent windows.

[0023] A water-blocking valve plate 9 is provided at the bottom of the inner sleeve 2, and a water-proof rubber ring adapted to the inner wall of the pressure inlet cavity 3 is fitted around the periphery of the water-blocking valve plate 9. Specifically, the water-blocking valve plate 9 has a circular plate structure, and its outer circumference is adapted to fit the wall surface of the pressure inlet cavity 3. That is to say, the water-blocking valve plate 9 acts as a baffle that is in direct contact with the water. The upper end of the water-blocking valve plate 9 is connected to the bottom of the inner sleeve 2 through a hinge shaft. The water-proof rubber ring is used to prevent water from flowing from the periphery of the water-blocking valve plate 9 into the upper part of the water-blocking valve plate 9 when external water enters the pressure inlet cavity 3, so as to ensure that the water can act on the water-blocking valve plate 9, thereby controlling the corresponding relationship between the axial displacement and depth change of the inner sleeve 2.

[0024] The sampling kit also includes a locking assembly for locking the inner sleeve 2. The locking assembly includes a locking chuck 10 located at the top of the inner sleeve 2 and a wedge-shaped locking member 11 located on the inner wall of the pressure inlet chamber 3. The locking assembly is configured such that when the compression spring 5 is compressed to its extreme value, the locking chuck 10 pushes the wedge-shaped locking member 11 inward along the guide slope of the wedge-shaped locking member 11. After the locking chuck 10 passes the wedge-shaped locking member 11, the wedge-shaped locking member 11 is reset and extended under the action of the elastic component 12, and is located below the locking chuck 10, thus limiting and locking the inner sleeve 2. Specifically, when the inner sleeve 2 moves to the preset end point of its stroke under hydrostatic pressure, its position is temporarily maintained at its extreme value by a mechanical limiting structure to prevent the inner sleeve 2 from moving downward relative to the outer shell 1 due to the decrease in external hydrostatic pressure during subsequent retraction (upward pulling back). During the downward movement of the inner sleeve 2 relative to the outer shell 1, each layered sampling chamber 6 will reconnect with the external water body, which can lead to sample cross-contamination and consequently reduce sample accuracy. This application achieves relative locking between the outer shell 1 and the inner sleeve 2 without requiring additional electronic control or drive components.

[0025] The outer casing 1 corresponding to the wedge-shaped locking member 11 is provided with an operating port 13 extending into the pressure inlet cavity 3. An elastic component 12 is disposed within the operating port 13. The elastic component 12 is used to push the wedge-shaped locking member 11 towards the pressure inlet cavity 3. The lower end face of the wedge-shaped locking member 11 forms a guide slope for the locking chuck 10 to push against it, so that when the locking chuck 10 moves upward, it presses the wedge-shaped locking member 11 into the operating port 13. After the locking chuck 10 passes, the wedge-shaped locking member 11, under the action of the elastic component 12, re-enters the pressure inlet cavity 3, thereby forming a downward stop on the locking chuck 10. Specifically, a first limiting block is provided within the operating port 13, and a limiting ring is provided on the wedge-shaped locking member 11. The elastic component 12 is sleeved on the wedge-shaped locking member 11 and located between the first limiting block and the limiting ring. Because the lower end face of the wedge-shaped locking member 11 is set as a guide slope, when the locking chuck 10 moves upward and contacts the slope, the wedge-shaped locking member 11 will retract radially along the operating port 13 under the thrust of the slope (i.e., move horizontally towards the outer wall of the outer casing 1). After the locking chuck 10 passes the wedge-shaped locking member 11, the elastic component 12 loses the external force and elastically recovers, pushing the wedge-shaped locking member 11 back to its original position, so that it re-enters the pressure inlet cavity 3 and is located below the locking chuck 10, forming a support point to prevent the wedge-shaped locking member 11 from falling back. Preferably, a second limiting block is also provided on the side of the operating port 13 facing the inner sleeve 2 to limit and block the limiting ring. At the same time, a lifting part is provided on the end of the wedge-shaped locking member 11 away from the guide slope, which makes it convenient for the operator to release the inner sleeve 2.

[0026] The pressure guide port 4 is located at the bottom center of the outer casing 1. A sand filter cover 14 is provided around the pressure guide port 4 to reduce the impact of mud and sand blockage and local turbulence on hydrostatic pressure transmission. Specifically, the sand filter cover 14 is used to prevent fine particles of mud and sand, suspended matter, and debris from directly entering the pressure inlet cavity 3 in the complex environment of deep aquifers, avoiding pressure transmission efficiency caused by sediment blockage of the pressure guide port 4. Since this application relies on hydrostatic pressure to drive the inner casing 2 to generate axial displacement, the sand filter cover 14 performs primary filtration of the incoming water while weakening water pressure transmission, reducing pressure fluctuations caused by blockage and local eddies, making the pressure state in the pressure inlet cavity 3 more stable. At the same time, the pressure guide port 4 is located at the bottom center, which is conducive to directly sampling a relatively uniform hydrostatic pressure signal from the bottom area of ​​the well, reducing the interference of lateral disturbance and bias pressure on the sampling action, thereby improving the stability of depth identification and stratified conduction.

[0027] An anti-rotation guide structure is provided between the outer shell 1 and the inner sleeve 2. The anti-rotation guide structure includes a guide pin disposed on the outer wall of the inner sleeve 2 and an anti-rotation guide groove disposed on the inner wall of the pressure inlet cavity 3. The guide pin is slidably disposed within the groove of the anti-rotation guide groove. Specifically, the anti-rotation guide structure is used to restrict the circumferential rotation of the inner sleeve 2 during axial reciprocating motion, so that the inner sleeve 2 always maintains a preset angle posture, thereby ensuring that each alignment sampling window 7 is aligned with the corresponding shell conduction window 8 in a preset direction.

[0028] The upper part of the pressure inlet cavity 3 is provided with a spring seat for the compression spring 5 to abut against. The spring preload adjustment component 15 is either an adjusting nut or a clamping sleeve. Specifically, the compression spring 5 is used to provide a restoring force opposite to the displacement direction of the inner sleeve 2 under the action of external hydrostatic pressure, and to push the inner sleeve 2 back to its original position or maintain a preset stroke state after the external hydrostatic pressure weakens. The spring seat ensures that the compression spring 5 is stably stressed axially during compression and rebound. The spring preload adjustment component 15 can be calibrated and fine-tuned according to different drilling depths, different aquifer water pressure conditions, and different sampling layers to adjust the initial stress state of the compression spring 5. By adjusting the initial compression amount, the pressure threshold at which the inner sleeve 2 begins to generate effective displacement can be changed, so that a more accurate pressure correspondence is formed between the sampling action and the target depth, avoiding threshold deviation caused by changes in groundwater density, local temperature differences, or wellbore disturbance. This structure can adapt to different geological conditions and different depth ranges, improving the versatility and engineering adaptability of this application, and also facilitating the setting and on-site calibration of parameters by operators.

[0029] Example 2, based on Example 1, proposes a sampling method for a sampling device, including the following steps: S1: Based on the preset depth range of the target borehole, the hydrostatic pressure threshold corresponding to each layer sampling chamber 6 is pre-calibrated, and the initial compression of the compression spring 5 is adjusted according to the hydrostatic pressure threshold, so that the inner casing 2 forms the corresponding axial displacement stroke under different pressures. At the same time, combined with the borehole depth parameters, aquifer burial depth parameters, and preset sampling layers, the correspondence between each layer sampling chamber 6 and the shell conductive window 8 is numbered, so that each layer sampling chamber 6 has a unique depth correspondence, avoiding layer confusion during sampling.

[0030] S2: The lifting mechanism lowers the outer casing 1 as a whole into the target borehole. During the lowering process, the axial stability of the outer casing 1 is maintained, allowing the pressure guide port 4 to gradually enter the target aquifer water environment. After the pressure guide port 4 enters the water body, the water from the external aquifer enters the pressure inlet chamber 3 through the pressure guide port 4. Under the filtration effect of the sand filter cover 14, the water entering the pressure inlet chamber 3 undergoes preliminary rectification and sand blocking treatment, so that the pressure inlet chamber 3 quickly establishes a pressurized state consistent with the external static water environment, providing a stable pressure source for the displacement of the inner casing 2.

[0031] S3: As the outer shell 1 continues to descend, the hydrostatic pressure in the pressure inlet chamber 3 continues to act on the inner sleeve 2, causing the inner sleeve 2 to undergo axial relative displacement under the elastic reaction force of the compression spring 5. At this time, the inner sleeve 2 only moves axially along the direction limited by the anti-rotation guide structure without circumferential rotation, thereby ensuring that the alignment sampling window 7 always maintains the preset circumferential posture and gradually approaches the corresponding shell conduction window 8 at different descent depths.

[0032] S4: When the outer shell 1 is lowered to a preset depth, the lowermost alignment sampling window 7 and the corresponding lowermost shell conduction window 8 first achieve axial alignment. The two, originally in a misaligned and closed state, form a connecting channel. Water from the external aquifer enters the corresponding layered sampling chamber 6 through the pressure inlet 4, the pressure inlet cavity 3, and the alignment connecting channel. During this process, the water-resistant rubber ring seals the inner wall of the pressure inlet cavity 3, preventing non-target layer water from flowing around and entering, ensuring that the water entering the layered sampling chamber 6 corresponds one-to-one with the target depth position, thereby obtaining a sampling sample corresponding to a precise depth.

[0033] S5: As the outer shell 1 continues to move downwards, the inner sleeve 2 moves further upwards under the balance of hydrostatic pressure changes and the elastic force of the compression spring 5, causing the next layered sampling chamber 6 to form a new axial alignment and connection with the corresponding shell conduction window 8. At the same time, the previous layered sampling chamber 6 returns to its misaligned and closed state as the window position shifts relative to the previous state, thus isolating the sampled chamber from the external aquifer again, preventing the sampled water from leaking out or mixing with water from adjacent layers during subsequent movement, thereby achieving continuous layered sampling across multiple depth ranges and maintaining the independence of each sample layer.

[0034] S6: When the inner sleeve 2 moves upward to the preset limit stroke, the locking chuck 10 pushes the wedge-shaped locking member 11 inward along the guide slope of the wedge-shaped locking member 11. After the locking chuck 10 passes the wedge-shaped locking member 11, the wedge-shaped locking member 11 is reset and extended under the action of the elastic component 12 and is locked below the locking chuck 10 to form a fall-off limit lock for the inner sleeve 2, preventing the rebound from causing the internal sample to mix, and ensuring that the layered sampling cavity 6 that has completed sampling is no longer connected to the outside, thereby improving the stability and sample fidelity after sampling.

[0035] S7: After all the preset layered sampling chambers 6 have completed sampling, the outer shell 1 is lifted upwards by the lifting mechanism, allowing the sampling kit to exit the borehole. During the lifting process, the water samples collected and sealed in each layered sampling chamber 6 remain independent and are not affected by external water disturbance.

[0036] In step S1 above, the preset compression amount of the compression spring 5 is calibrated according to the correspondence between depth, hydrostatic pressure, and axial displacement, so that the inner sleeve 2 can only stop at the corresponding discrete sampling points at different depths, avoiding cross-contamination between adjacent layered sampling chambers 6. Specifically, by pre-calculating the hydrostatic pressure corresponding to different depths, the compression amount of the compression spring 5 can be set to several discrete levels, so that the inner sleeve 2 will only undergo the corresponding displacement when it reaches a specific pressure range, thereby ensuring that the alignment sampling window 7 and the shell conduction window 8 only form a short-term connection at the preset layer. The continuously changing depth signal is converted into a mechanically executable layering trigger condition, avoiding window misalignment or cross-contamination problems caused by excessive displacement.

[0037] Example 3: Based on Example 2, this example proposes the working principle of the first layered sampling cavity conduction.

[0038] like Figure 5 The diagram shows the relative positions of the outer shell 1 and the inner sleeve 2 when disassembled. It should be noted that points a, b, and c on the inner sleeve 2 are not on the same side of the inner sleeve 2; similarly, points a, b, and c on the outer shell 1 are on the same side of the outer shell 1. This diagram is only for visual representation of the changes in height.

[0039] Assume that the inner sleeve 2 has three layered sampling cavities 6, and the outer shell 1 has three shell-connecting windows 8. The three layered sampling cavities 6 are labeled a, b, and c from bottom to top, and the three shell-connecting windows 8 are also labeled a, b, and c from bottom to top.

[0040] Initially, the descent depth of the outer shell 1 is insufficient to trigger the displacement threshold of the compression spring 5. Only after reaching the first preset depth does the inner sleeve 2 slowly rise relative to the outer shell 1. At this point, point a on the inner sleeve 2 is about to connect with point a on the outer shell 1. During this connection process, the sample water enters point a on the inner sleeve 2. At this time, points b and c on the inner sleeve 2 are not connected with points b or c on the outer shell 1.

[0041] Example 4: Based on Example 3, this example proposes the working principle of the second layered sampling cavity conduction.

[0042] like Figure 6As shown, when the second preset depth is reached, b on the inner sleeve 2 will be connected to b on the outer sleeve 1, while a on the inner sleeve 2 has already been misaligned and closed with a on the outer sleeve 1. Furthermore, c on the inner sleeve 2 is still not connected to c on the outer sleeve 1. That is, during the connection process between b on the inner sleeve 2 and b on the outer sleeve 1, a at the front end has been misaligned and closed, while c at the rear end or more layered sampling cavities 6 are in a closed state, ensuring that sample collection at this depth is performed only through one layered sampling cavity 6.

[0043] Example 5, based on Example 4, proposes the working principle of the third layered sampling cavity conduction.

[0044] like Figure 7 As shown, when the third preset depth is reached, c on the inner sleeve 2 will be connected to c on the outer sleeve 1. At this time, b on the inner sleeve 2 has already been misaligned and closed with b on the outer sleeve 1, and a on the inner sleeve 2 has already been misaligned and closed with a on the outer sleeve 1. That is, during the connection process between c on the inner sleeve 2 and c on the outer sleeve 1, a and b at the front end have been misaligned and closed until the sample water at the preset depth is collected. By relatively locking the inner sleeve 2 and the outer sleeve 1, the sample water is ensured to remain locked within each layered sampling chamber 6. After the outer sleeve 1 is retracted to the ground, the operator releases the lock on the inner sleeve 2 and collects the sample water from each layered sampling chamber 6 using external extraction equipment.

[0045] Example 6: Based on Example 5, this example proposes a calibration and debugging procedure for a sampling method.

[0046] Since the external hydrostatic pressure first acts on the pressure-conducting port 4 and its corresponding water-blocking valve 9 located at the bottom of the outer casing 1, and each layered sampling chamber 6 is located at different heights on the side wall of the inner sleeve 2, there is a preset axial offset relationship between the depth of the pressure-conducting port 4 and the actual sampling depth corresponding to each layered sampling chamber 6. Before the device is deployed, this axial offset relationship can be calibrated based on sampling experiments, and the target sampling depth corresponding to each layered sampling chamber 6 can be determined by combining the axial distance from each layered sampling chamber 6 to the pressure-conducting port 4.

[0047] For example, if the axial distance between the lowest layered sampling chamber 6 and the pressure-conducting port 4 is 2m, and the axial distance between two adjacent layered sampling chambers 6 is 5m, then when groundwater samples need to be collected at 30m, 35m, and 40m, the corresponding lowering depths of the pressure-conducting port 4 are 32m, 37m, and 42m, respectively. That is, when the outer shell 1 is lowered to a depth of 32m where the pressure-conducting port 4 is located, the lowest layered sampling chamber 6 corresponds to a 30m sampling layer; when the pressure-conducting port 4 is at a depth of 37m, the next lower layered sampling chamber 6 corresponds to a 35m sampling layer; and when the pressure-conducting port 4 is at a depth of 42m, the next upper layered sampling chamber 6 corresponds to a 40m sampling layer.

[0048] Furthermore, taking groundwater as an approximation of freshwater as an example, the water density ρ can be taken as 1000 kg / m³, and the gravitational acceleration g as 9.8 m / s². The hydrostatic pressure P can then be estimated using the formula P = ρgh. Accordingly, when the pressure guide port 4 is located at a depth of 32 m, the corresponding hydrostatic pressure is approximately 0.314 MPa; at a depth of 37 m, it is approximately 0.363 MPa; and at a depth of 42 m, it is approximately 0.412 MPa. By pre-adjusting the initial compression of the compression spring 5, the inner sleeve 2 can generate corresponding axial displacements near the aforementioned pressure thresholds, thereby enabling accurate alignment and communication between the corresponding alignment sampling window 7 and the shell conduction window 8, thus completing the stratified sampling corresponding to 30 m, 35 m, and 40 m.

[0049] It should be noted that the above depth and pressure parameters are for illustrative purposes only, and can be adjusted accordingly based on groundwater density, well conditions, and sampling layer spacing in actual applications.

[0050] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A deep aquifer water quality stratification sampling device, comprising a sampling kit for probing down a borehole, characterized in that: The sampling kit includes an outer shell (1) and an inner sleeve (2) movably disposed within the outer shell (1). The lower end of the outer shell (1) is provided with a pressure inlet cavity (3). The bottom of the pressure inlet cavity (3) is provided with a pressure guide port (4) communicating with the external aquifer. The upper part of the pressure inlet cavity (3) is provided with a compression spring (5). The upper end of the inner sleeve (2) is connected to the compression spring (5) so that it can move axially relative to the outer shell (1) under the action of hydrostatic pressure. The compression spring (5) is provided with a spring preload adjustment component (15) to change the initial compression amount of the compression spring (5), thereby corresponding to the hydrostatic pressure threshold of different depth ranges. The inner sleeve (2) has multiple layered sampling chambers (6) spaced axially in its inner cavity. Each layered sampling chamber (6) has a positioning sampling window (7) on its side wall. The outer shell (1) has multiple corresponding shell conduction windows (8) on its axial region corresponding to the positioning sampling window (7). The outer periphery of the inner sleeve (2) and the inner wall of the pressure inlet cavity (3) are in sliding sealing fit. The axial distance between two adjacent shell conduction windows (8) is greater than the axial distance between two adjacent alignment sampling windows (7). The multiple alignment sampling windows (7) are arranged in a staggered circumferential pattern. The opening azimuth angles of two adjacent alignment sampling windows (7) are different, so that each alignment sampling window (7) faces a different circumferential orientation in the top view direction. The sampling kit is configured such that, under normal conditions, the alignment sampling window (7) and the shell conduction window (8) are in an axially misaligned and closed state. When the inner sleeve (2) undergoes axial displacement under hydrostatic pressure, multiple alignment sampling windows (7) are sequentially aligned and connected with the corresponding multiple shell conduction windows (8), and the alignment and connection sequence is from bottom to top, so that the water in the external aquifer enters the corresponding layered sampling chamber (6) to complete the layered sampling.

2. The deep aquifer water quality stratification sampling device according to claim 1, characterized in that: Multiple housing conductive windows (8) are arranged at equal intervals along the axial direction, and multiple alignment sampling windows (7) are arranged at equal intervals along the axial direction.

3. The deep aquifer water quality stratification sampling device according to claim 1, characterized in that: The bottom of the inner sleeve (2) is provided with a water-blocking valve plate (9), and the periphery of the water-blocking valve plate (9) is fitted with a water-proof rubber ring that is adapted to the inner wall of the pressure inlet cavity (3).

4. The deep aquifer water quality stratification sampling device according to claim 1, characterized in that: The sampling kit is also provided with a locking assembly for locking the inner sleeve (2). The locking assembly includes a locking chuck (10) disposed on the top of the inner sleeve (2) and a wedge-shaped locking member (11) disposed on the inner wall of the pressure inlet cavity (3). The locking assembly is configured such that when the compression spring (5) is compressed to its extreme value, the locking chuck (10) pushes the wedge-shaped locking member (11) inward along the guide slope of the wedge-shaped locking member (11). When the locking chuck (10) passes the wedge-shaped locking member (11), the wedge-shaped locking member (11) is reset and extended under the action of the elastic component (12) and is located below the locking chuck (10) to form a fall-off limit lock on the inner sleeve (2).

5. The deep aquifer water quality stratification sampling device according to claim 4, characterized in that: The outer shell (1) corresponding to the wedge-shaped locking member (11) is provided with an operation port (13) that extends to the pressure inlet cavity (3). An elastic component (12) is provided in the operation port (13). The elastic component (12) is used to push the wedge-shaped locking member (11) toward the pressure inlet cavity (3). The lower end face of the wedge-shaped locking member (11) forms a guide slope for the locking chuck (10) to push, so that when the locking chuck (10) moves upward, it presses the wedge-shaped locking member (11) into the operation port (13). After the locking chuck (10) passes, the wedge-shaped locking member (11) re-extends into the pressure inlet cavity (3) under the action of the elastic component (12), thereby forming a downward stop on the locking chuck (10).

6. The deep aquifer water quality stratification sampling device according to claim 1, characterized in that: The pressure guide port (4) is located at the bottom center of the outer shell (1). A sand filter cover (14) is provided on the outer periphery of the pressure guide port (4) to reduce the impact of mud and sand blockage and local turbulence on the transmission of hydrostatic pressure.

7. The deep aquifer water quality stratification sampling device according to claim 1, characterized in that: An anti-rotation guide structure is provided between the outer shell (1) and the inner sleeve (2). The anti-rotation guide structure includes a guide pin disposed on the outer wall of the inner sleeve (2) and an anti-rotation guide groove disposed on the inner wall of the pressure inlet cavity (3). The guide pin is slidably disposed in the channel of the anti-rotation guide groove.

8. The deep aquifer water quality stratification sampling device according to claim 1, characterized in that: The upper part of the pressure inlet cavity (3) is provided with a spring seat for the compression spring (5) to abut against, and the spring preload adjustment component (15) is either an adjustment nut or a compression sleeve.

9. A sampling method based on the sampling device of claim 5, characterized in that, Includes the following steps: S1: Based on the preset depth range of the target borehole, the initial compression amount of the compression spring (5) is preset so that each layered sampling chamber (6) corresponds to the preset depth pressure threshold. S2: The outer shell (1) is lowered into the target borehole by the lifting mechanism. When the outer shell (1) descends and reaches the aquifer water, the water enters the pressure inlet chamber (3) through the pressure inlet (4) and generates a pressure difference pushing effect on the inner sleeve (2). S3: During the continuous descent of the outer shell (1), the inner sleeve (2) moves upward relative to the outer shell (1) along the axial direction under the action of pressure difference, overcoming the elastic force of the compression spring (5); S4: When the bottommost alignment sampling window (7) is aligned with the bottommost shell conduction window (8), the alignment sampling window (7) and the shell conduction window (8) change from misalignment and closure to conduction, and the water body of the external aquifer enters the layered sampling cavity (6) to obtain the sampling sample corresponding to the precise depth. S5: The outer shell (1) continues to descend, so that the next layered sampling cavity (6) forms a new alignment connection with the corresponding shell conduction window (8) in sequence. At the same time, the alignment sampling window (7) of the previous layered sampling cavity (6) and the shell conduction window (8) are misaligned and closed again, thereby completing the continuous layered sampling of multiple depth intervals. S6: When the inner sleeve (2) moves up to the preset limit stroke, the locking chuck (10) pushes the wedge lock (11) inward along the guide slope of the wedge lock (11). When the locking chuck (10) passes the wedge lock (11), the wedge lock (11) is reset and extended under the action of the elastic component (12) and locked below the locking chuck (10) to form a back-fall limit lock for the inner sleeve (2) and ensure that the layered sampling cavity (6) that has completed sampling is no longer connected to the outside. S7: After sampling is completed, the outer shell (1) is lifted upward by the lifting mechanism, and the water samples collected and sealed in each layered sampling chamber (6) remain in an independent state.

10. The sampling method according to claim 9, characterized in that: In step S1 above, the preset compression amount of the compression spring (5) is calibrated according to the relationship between depth, hydrostatic pressure and axial displacement, so that the inner sleeve (2) can only stop at the corresponding discrete sampling point at different depths, avoiding cross-contamination of adjacent layered sampling cavities (6).

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