A water body sampling device for elongate borehole environments

Abstract

The application discloses a water sampling device for long and narrow borehole environment, which comprises a long columnar shell, a sampling mechanism, a sampling pump and a pressure maintaining mechanism contained in the shell, the sampling pump is arranged along the axial direction, and the inlet of the sampling pump is communicated with the inside of the sampling mechanism; the device adopts a long columnar integrated structure, solves the space adaptation problem of large volume sampling in the long and narrow borehole with limited radial direction, and when the sampling pump operates, the sampling pump drives the acquisition of external water sample by extracting fluid from the sampling mechanism, meanwhile, the pressure drop formed by the inlet of the pump is directly used for triggering the action of the sealing mechanism, so that the internal flow passage of the sampling mechanism is automatically closed, the sampling driving and sealing triggering functions are integrated, the automatic linkage of steps is realized, the structure is simple, and the reliability and sealing instantaneity of work in extreme environments such as deep sea and under ice are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of sampling and pressure holding technology, and specifically to a water sampling device for narrow borehole environments. Background Technology

[0002] As scientific exploration of extreme environments deepens, the need for water sampling within narrow openings, such as Antarctic subglacial lakes, deep-sea drilling sites, and seabed boreholes, is becoming increasingly prominent. These environments share the common characteristic of strictly limited radial dimensions but significant axial depth, posing extremely stringent requirements for sampling device design. Traditional pressure-holding sampling equipment typically relies on radial space to arrange the sampling chamber, power unit, and pressure compensation system, making it difficult to directly adapt to such slender channels. Forcibly reducing the radial dimension results in a significantly insufficient sample volume for a single operation, failing to meet the sample quantity requirements for subsequent analysis. External or modular designs often face challenges such as poor connection reliability in extreme environments, operational complexity, and difficulty in achieving overall pressure holding.

[0003] While various deep-sea pressure-holding sampling devices exist in the existing technology, such as systems that use water-soluble materials for triggering or have active pressure compensation functions, most of them are designed to solve sampling or pressure-holding problems in general deep-sea environments. These devices either have structural shapes and dimensions that are incompatible with radially confined, narrow orifice operations, or their pressure-holding mechanisms are relatively independent of the sampling process, making it impossible to efficiently and reliably complete the integrated process from in-situ sampling, immediate sealing, to pressure maintenance within limited radial space. Therefore, how to design a water sampling device that can fully utilize axial space, achieve large volume, in-situ pressure holding, and automatic and reliable sealing under extreme radial size constraints has become a key technical bottleneck that has long remained unresolved in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a water sampling device for narrow borehole environments, aiming to solve the problems existing in the background technology.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a water sampling device for a narrow borehole environment, comprising: a long cylindrical shell, the radial dimension of which is adapted for lowering and retrieving within the narrow borehole; a sampling mechanism, which is housed within the long cylindrical shell and extends axially along the shell, for acquiring and containing water samples; a sampling pump, which is disposed within the shell and arranged axially, the inlet of the sampling pump communicating with the interior of the sampling mechanism; and a pressure-holding mechanism, which is housed within the shell and in fluid communication with the sampling mechanism; wherein, the sampling pump is configured to: during operation, drive the sampling mechanism to acquire external water samples by drawing fluid from the sampling mechanism; the operation of the sampling pump also causes a pressure drop at its inlet, which triggers a sealing mechanism to close the internal fluid channel of the sampling mechanism.

[0006] Furthermore, the sampling mechanism includes: a sampling chamber, which has an axially movable sampling piston inside, the sampling piston dividing the sampling chamber into a first chamber and a second chamber that are isolated from each other, the second chamber forming a cavity for containing water samples and having a sampling port communicating with the outside; wherein, the inlet of the sampling pump is connected to the first chamber; when the sampling pump is running, it draws fluid from the first chamber, driving the sampling piston to move in the direction of decreasing volume of the first chamber, thereby allowing the external water sample to enter the second chamber through the sampling port.

[0007] Furthermore, the pressure-holding mechanism includes a pressure balancing chamber and an energy storage chamber; the pressure balancing chamber has a balancing inlet that communicates with the external environment, and a first piston is provided inside it, which is connected to the first chamber of the sampling chamber through a first flow channel; the energy storage chamber has a second piston inside it, which divides the energy storage chamber into a gas chamber filled with compressed gas and a liquid chamber filled with liquid, and the liquid chamber is connected to the first chamber of the sampling chamber through a second flow channel.

[0008] Furthermore, the sealing mechanism includes: A plunger, initially magnetically coupled to the sampling piston and located within the first chamber; a sealing seat, located at the end of the sampling chamber communicating with the inlet of the sampling pump; wherein the plunger is configured such that when the sampling piston moves to align the plunger with the sealing seat, under the pressure drop formed at the inlet of the sampling pump during operation, the force acting on the plunger toward the sampling pump overcomes the magnetic coupling force, causing the plunger to move and embed into the sealing seat, thereby sealing the fluid passage between the first chamber and the inlet of the sampling pump.

[0009] Furthermore, the sampling pump is a cam-type plunger pump, including a motor, a cam driven by the motor, a roller assembly that mates with the cam profile, a pump plunger driven by the roller assembly to perform axial reciprocating motion, and an inlet check valve and an outlet check valve respectively connected to the pump chamber.

[0010] Furthermore, the first flow channel is provided with a first one-way valve that only allows fluid to flow from the pressure balance chamber to the sampling chamber.

[0011] Furthermore, the cross-sectional area of ​​the pressure balancing chamber is smaller than the cross-sectional area of ​​the sampling chamber.

[0012] Furthermore, the deionized water fills the space between the first piston and the first flow channel.

[0013] Furthermore, the gas chamber of the energy storage cavity is pre-filled with nitrogen.

[0014] Furthermore, when the sampling piston moves to the end limit position of the first chamber, the sampling pump is triggered to stop operating.

[0015] This invention describes a water sampling device for narrow borehole environments. Its advantages lie in its axially integrated design of a long cylindrical shell, which effectively solves the spatial adaptation problem of large-volume sampling within narrow boreholes with strictly limited radial dimensions. During operation, the sampling pump draws fluid from the sampling mechanism to drive the acquisition of external water samples. Simultaneously, the pressure drop at the pump inlet directly triggers the sealing mechanism, automatically sealing the internal flow channels of the sampling mechanism. This design integrates sampling drive and sealing trigger functions, achieving automatic linkage of steps. Its simple structure significantly improves reliability and sealing immediacy in extreme environments such as deep sea and under ice. Attached Figure Description

[0016] Figure 1 This is a perspective view of the external structure of the system according to an embodiment of the present invention; Figure 2 This is a cross-sectional view of the initial state of an embodiment of the present invention; Figure 3 This is a cross-sectional view of the sampling pump according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the internal structure of the flow guide shield according to an embodiment of the present invention; Figure 5 This is a simplified system diagram of the initial state of an embodiment of the present invention; Figure 6 This is a simplified system diagram of the diving process state according to an embodiment of the present invention; Figure 7 This is a simplified system diagram showing the working state of the sampling pump according to an embodiment of the present invention; Figure 8This is a simplified system diagram of the recycling state according to an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached drawings: 1. Flow guide; 11. Upper end cover of the flow guide; 12. Lower end cover of the flow guide; 13. Connector; 14. Lifting ring; 2. Sampling chamber; 21. Sampling piston; 22. Shut-off valve; 23. Plunger; 24. One-way valve of the sampling chamber; 3. Sampling pump; 31. Drive motor; 32. Cam; 33. Roller assembly; 34. Pump plunger; 35. Inlet one-way valve; 36. Outlet one-way valve; 4. Pressure balance chamber; 41. First piston; 42. First one-way valve; 5. Energy storage chamber; 51. Second piston; 6. Sealing hole; 7. Circuit chamber; 8. Pressure sensor. Detailed Implementation

[0018] The specific embodiments of the water sampling device for narrow borehole environments of the present invention will now be described in detail with reference to the accompanying drawings. Those skilled in the art will understand that the following description is intended to illustrate the core principles and preferred implementations of the invention, and not to limit the invention.

[0019] This invention aims to solve the fundamental technical challenge of achieving in-situ, pressure-maintaining, and reliable sealing of large-volume water samples in narrow boreholes with extremely limited radial space (such as Antarctic subglacial lake boreholes and deep-sea wells). Traditional equipment, due to structural limitations, cannot simultaneously meet the requirements of radial dimensional constraints and large-volume sampling, and pressure maintenance and inlet sealing during sampling often rely on complex external systems. Therefore, this invention abandons the traditional radial expansion approach and creatively proposes an axially integrated, long cylindrical integrated solution. Its core lies in driving sampling through the active displacement of internal fluids and triggering a reliable mechanical seal using the device's own workflow.

[0020] Please refer to Figures 1-8. The device of the present invention mainly includes a long cylindrical housing and a functional system integrated within the housing.

[0021] The elongated cylindrical shell is a flow guide shroud 1, with an upper flow guide shroud cover 11 and a lower flow guide shroud cover 12, both with curved surfaces, connected in the middle by a hollow cylindrical connector 13, forming a coaxial cylindrical cavity. The cylindrical connector 13 has multiple through holes, allowing external ambient water to freely enter and exit the cavity. The streamlined curved end design of the flow guide shroud 1 helps maintain alignment during lowering and raising of the device in the borehole, reducing the risk of jamming and protecting the sampling port of the shell. A lifting ring 14 is provided on the outer side of the upper flow guide shroud cover 11 for connecting the deployment and recovery cable.

[0022] The flow guide shroud 1 is the core pressure-bearing and load-bearing structure of the device. Its outer diameter is precisely designed according to the diameter of the target borehole to ensure smooth passage, while its axial length provides space to accommodate the large-volume sampling chamber 2 and other components. The sampling mechanism, sampling pump 3, and pressure holding mechanism are sequentially integrated along the axial direction inside the housing.

[0023] The core of the sampling mechanism is a cylindrical sampling chamber 2. Inside the sampling chamber 2 is a sampling piston 21 that can slide axially in a sealed manner. This piston divides the interior of the sampling chamber 2 into two isolated chambers: a first chamber and a second chamber. The first chamber is connected to the inlet of the sampling pump 3. The second chamber serves as a container for collecting water samples, and its end has a sampling port that communicates with the external environment. This sampling port is equipped with a one-way valve 24 that only allows external water to flow in. For ease of operation, each end of the sampling chamber 2 is also equipped with a manual or controllable shut-off valve 22. The shut-off valve 22 at the first chamber end is used to fill and replenish the liquid circuit of the entire system (including the first chamber) with deionized water, while the shut-off valve 22 at the second chamber end is used to safely transfer the sample after recovery.

[0024] The sampling pump 3 is a compact cam-type plunger pump with its pump body arranged axially along the guide shroud 1. The pump includes a drive motor 31, a cam 32 driven by the motor shaft, a roller assembly 33 that engages with the curved surface of the cam 32, and a pump plunger 34 that is pushed by the roller assembly 33 to perform axial reciprocating motion. An inlet check valve 35 and an outlet check valve 36 are provided on the pump chamber. The inlet of the sampling pump 3 is connected to the first chamber of the sampling chamber 2 via a pipeline, while its outlet leads to the external environment of the casing. The core function of this pump is to actively extract deionized water from the first chamber during the sampling stage.

[0025] The pressure-holding mechanism is a pressure management system consisting of a pressure balancing chamber 4 and an energy storage chamber 5 working in concert.

[0026] The pressure balancing chamber 4 has a balancing inlet that communicates with the external environment (through the cavity of the flow guide shroud 1). A first piston 41 is installed inside the chamber, dividing it into two parts: a chamber directly adjacent to the balancing inlet and a chamber on the other side. The other side chamber is filled with deionized water and is connected to the first chamber of the sampling chamber 2 via a first flow channel. A first one-way valve 42 is installed on this first flow channel, its direction set to allow liquid to flow only from the pressure balancing chamber 4 to the sampling chamber 2. A key design feature is that the cross-sectional area of ​​the pressure balancing chamber 4 is smaller than that of the sampling chamber 2.

[0027] The energy storage chamber 5 is equipped with a second piston 51, which strictly divides the energy storage chamber 5 into two non-communicating chambers: one is a sealed gas chamber pre-filled with high-pressure nitrogen; the other is a liquid chamber filled with deionized water. The liquid chamber is connected to the first chamber of the sampling chamber 2 through a second flow channel. In the initial state, the gas chamber of the energy storage chamber 5 is pre-filled with nitrogen.

[0028] The sealing mechanism is a key innovation for achieving automatic and reliable sealing after sampling. It includes a plunger 23 and a sealing seat. The sealing seat has a sealing hole 6 communicating with the first flow channel, which in turn communicates with the sampling chamber 2. In its initial state, the plunger 23 is magnetically attached to the sampling piston 21 and located within the first chamber. The sealing seat is fixedly disposed at the end of the sampling chamber 2, specifically at the port where the first chamber connects to the inlet of the sampling pump 3. A sealing ring may be provided on the contact surface between the plunger 23 and the sealing hole 6. Preferably, the sealing seat can also be integrally formed with the end of the sampling chamber 2.

[0029] A sealed circuit cavity 7 is also integrated inside the flow guide shroud 1, which houses a control circuit board and a battery pack (not shown). A pressure sensor 8 is installed in the first chamber of the sampling chamber 2. The sensing end of the pressure sensor 8 is exposed to the deionized water in the first chamber, and its signal output end is electrically connected to the control circuit board in the circuit cavity 7 via a pressure-resistant wire for real-time monitoring of the fluid pressure in the first chamber.

[0030] A complete workflow of the device of the present invention is as follows, which clearly demonstrates how the various components work together to solve the aforementioned fundamental problem: Phase 1: Initial preparation and descent.

[0031] Before deployment, sufficient deionized water is injected into the first chamber of sampling chamber 2, the corresponding chambers of pressure balance chamber 4, and the liquid chamber of energy storage chamber 5 through the shut-off valve 22 at the first chamber end of sampling chamber 2. After completion, the shut-off valve 22 is closed. The device is connected to the deployment system via the lifting ring 14 on the flow guide shroud 1 and lowered into the target borehole. The arc-shaped design of the flow guide shroud 1 helps it move smoothly and center in the borehole.

[0032] Phase Two: Descent and Pressure Pre-Equilibrium.

[0033] As the device descends, the external environmental pressure increases. High-pressure seawater enters the annular cavity through the holes in the flow guide shroud 1 and acts on one side of the first piston 41 through the balance inlet of the pressure balance chamber 4. Since the first one-way valve 42 on the first flow channel allows liquid to flow out, and the piston area of ​​the pressure balance chamber 4 is relatively small, the external pressure mainly drives the first piston 41 to move, smoothly injecting the deionized water in the pressure balance chamber 4 into the first chamber of the sampling chamber 2 through the first one-way valve 42. This causes the pressure in the first chamber of the sampling chamber 2 and the liquid chamber of the energy storage chamber 5 connected to it to rise synchronously. The increased pressure in the liquid chamber of the energy storage chamber 5 drives the second piston 51 to move, compressing the nitrogen in the gas chamber and converting the environmental pressure into the elastic potential energy of the nitrogen for storage. This process continues until the internal pressure of the system is basically balanced with the external environmental pressure. Since the area of ​​the sampling piston 21 is much larger than the piston area of ​​the pressure balance chamber 4, under the same pressure, the resultant force acting on the sampling piston 21 keeps it basically stationary.

[0034] Phase 3: Pump-driven replacement sampling.

[0035] During descent, a pressure sensor in the first chamber monitors pressure changes in real time, and the control system determines whether the device is at the target depth based on the pressure value. Once the device reaches the predetermined sampling depth and stabilizes, the sampling pump 3 starts under the command of the control system. The sampling pump 3 draws deionized water from the first chamber of sampling chamber 2, which is connected to its inlet, and discharges it into the external environment. As the liquid in the first chamber is continuously drawn out, its internal pressure generates a pressure drop relative to the second chamber (which is still connected to the external high-pressure seawater through the one-way valve of the sampling port). Under this pressure difference, the sampling piston 21 begins to move smoothly in the direction of decreasing volume in the first chamber. The movement of the sampling piston 21 causes the volume of the second chamber to increase, and the internal pressure is slightly lower than the external environmental pressure, so that the seawater to be sampled is continuously and isobarically "displaced" into the second chamber through the one-way valve of the sampling port. Throughout the sampling process, the energy storage chamber 5 absorbs the small fluctuations in system pressure caused by pump pulsation and piston movement through the slight expansion or compression of nitrogen in its gas chamber, ensuring that sampling is carried out in a stable pressure environment.

[0036] Phase 4: Sealing Trigger and Completion.

[0037] As the sampling pump 3 continues to operate, the sampling piston 21 continues to move until it reaches the preset end point of its stroke. At this point, the plunger 23 carried on the sampling piston 21 moves into the sealing hole 6 of the sealing seat. Since the sampling pump 3 is still running, the side of the plunger 23 closest to the sampling pump 3 maintains a lower fluid pressure. This continuous pressure difference causes the plunger 23 to experience a net force directed towards the sealing seat. When this force exceeds the magnetic force that attracts the plunger 23 to the sampling piston 21, the plunger 23 disengages from the sampling piston 21, moves rapidly under the pressure difference, and finally embeds itself into the sealing hole 6, achieving a reliable seal through the sealing ring, thereby cutting off the fluid passage between the first chamber of the sampling chamber 2 and the inlet of the sampling pump 3. Subsequently, the sampling pump 3 stops operating after detecting that the piston has reached its end point or after a predetermined time has elapsed. Since the flow channel has been closed, the lower pressure state of the plunger 23 on the sealing seat side is maintained, ensuring a stable seal.

[0038] Phase 5: Rise and sustained pressure.

[0039] After sampling and sealing, the device begins its ascent for recovery. As the external environmental pressure decreases, the pressure of the seawater sample in the second chamber of sampling chamber 2 tends to decrease accordingly. At this time, the pre-compressed high-pressure nitrogen in the gas chamber of energy storage chamber 5 begins to expand, pushing its second piston 51 to move, injecting deionized water from the liquid chamber of energy storage chamber 5 back into the first chamber of sampling chamber 2 through the flow channel. Since the first and second chambers are rigidly separated by the sampling piston 21, the increase in pressure in the first chamber pushes the sampling piston 21, thereby applying a compensating pressure to the water sample in the second chamber, effectively counteracting the effect of the decrease in external pressure and achieving pressure-maintaining recovery.

[0040] During the sampling and recovery process, the pressure sensor 8 continuously monitors the pressure in the first chamber. The control circuit board receives and processes this pressure signal. Due to the transmission action of the sampling piston 21, the pressure change in the first chamber directly reflects the pressure state experienced by the sample chamber. By analyzing this pressure data, the control circuit board can confirm whether the nitrogen expansion compensation process of the energy storage chamber 5 is working as expected, thereby achieving real-time verification and recording of the system's pressure holding performance.

[0041] Phase 6: Sample recovery.

[0042] After the device is recovered to the deck or laboratory, in a safe and controlled environment, the shut-off valve 22 at the second chamber end of sampling chamber 2 can be opened to release the water sample under pressure to subsequent processing or analysis equipment.

[0043] In summary, this specific embodiment details how the present invention achieves axial large-volume integration under radial constraints through a long cylindrical shell; how the sampling pump 3 draws liquid from the first chamber to drive the sampling piston 21 to complete "displacement sampling"; how the pressure-coordinated management system composed of the pressure balance chamber 4, the energy storage chamber 5, and the first flow channel, the second flow channel, and the first one-way valve 42 connecting them achieves submersion balance, sampling pressure stabilization, and rising pressure holding; and how the pressure drop generated by the pump operation triggers the magnetically coupled plunger 23 to embed into the sealing seat, achieving automatic and reliable sealing. The entire solution is logically consistent, and all technical features described in the claims are fully embodied and described in detail in the embodiment, fully demonstrating the innovative technical solution adopted by the present invention to solve specific technical problems.

Claims

1. A water sampling device for use in narrow borehole environments, characterized in that, include: A long cylindrical shell, the radial dimensions of which are suitable for lowering and retrieving within the narrow borehole; A sampling mechanism, which is housed within the long cylindrical shell and extends axially along the shell, is used to acquire and contain water samples. The sampling mechanism includes a sampling chamber, which has an axially movable sampling piston inside. The sampling piston divides the sampling chamber into a first chamber and a second chamber that are isolated from each other. The second chamber forms a cavity for containing water samples and has a sampling port that communicates with the outside. A sampling pump is disposed within the housing and arranged axially, and the inlet of the sampling pump is in communication with the first chamber; as well as A pressure-holding mechanism is housed within the housing and is in fluid communication with the sampling mechanism; A sealing mechanism includes: a plunger initially connected to the sampling piston via magnetic coupling and located within the first chamber; and a sealing seat disposed at the end of the sampling chamber communicating with the inlet of the sampling pump. The sampling pump is configured to: draw fluid from the first chamber during operation, driving the sampling piston to move in the direction of decreasing volume of the first chamber, thereby allowing external water samples to enter the second chamber through the sampling port; the operation of the sampling pump also causes a pressure drop at its inlet; when the sampling piston moves to align the plunger with the sealing seat, under the pressure drop formed at its inlet during the operation of the sampling pump, the force on the plunger directed towards the sampling pump overcomes the magnetic coupling force, causing the plunger to move and embed into the sealing seat, thereby sealing the fluid passage between the first chamber and the sampling pump inlet.

2. The water sampling device according to claim 1, characterized in that, The pressure-holding mechanism includes a pressure balancing chamber and an energy storage chamber. The pressure balancing chamber has a balancing inlet that communicates with the external environment. It has a first piston inside and is connected to the first chamber of the sampling chamber through a first flow channel. The energy storage chamber has a second piston inside, which divides the energy storage chamber into a gas chamber filled with compressed gas and a liquid chamber filled with liquid. The liquid chamber is connected to the first chamber of the sampling chamber through a second flow channel.

3. The water sampling device according to claim 1, characterized in that, The sampling pump is a cam-type plunger pump, including a motor, a cam driven by the motor, a roller assembly that mates with the cam profile, a pump plunger driven by the roller assembly to perform axial reciprocating motion, and an inlet check valve and an outlet check valve respectively connected to the pump chamber.

4. The water sampling device according to claim 2, characterized in that, The first flow channel is provided with a first one-way valve that only allows fluid to flow from the pressure balance chamber to the sampling chamber.

5. The water sampling device according to claim 2, characterized in that, The cross-sectional area of ​​the pressure balancing chamber is smaller than that of the sampling chamber.

6. The water sampling device according to claim 2, characterized in that, The pressure balance chamber is filled with deionized water, which fills the space between the first piston and the first flow channel.

7. The water sampling device according to claim 2, characterized in that, The gas chamber of the energy storage chamber is pre-filled with nitrogen.

8. The water sampling device according to claim 1, characterized in that, When the sampling piston moves to the end limit position of the first chamber, the sampling pump is triggered to stop running.

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