A fixed-depth sampling device for groundwater detection

Abstract

The present invention relates to the technical field of auxiliary equipment for groundwater detection, and specifically to a fixed-depth sampling equipment for groundwater detection, which comprises a sampling tube and an inflatable member, wherein a sampling port is provided on the sampling tube, and the sampling port is connected to a detection well, and two base shells are sleeved on the sampling tube, and the two base shells are respectively located on the upper and lower sides of the sampling port and are connected to each other; an isolation air bag is sleeved on each base shell, and the isolation air bag is connected to the base shell and is configured to be able to expand when inflated, and to separate a water body at the sampling port from a water body above the sampling port or a water body below the sampling port along the axial direction of the sampling tube, so that the water body sampled from the sampling port is always a water sample at a target depth, thereby reducing sampling errors; an auxiliary air bag is connected to the base shell, and the auxiliary air bag is located between the two isolation air bags, and the auxiliary air bag is configured to be able to expand when inflated, so as to squeeze the water body at the sampling port into the sampling tube through the sampling port.

Description

Technical Field

[0001] The present invention relates to the technical field of auxiliary equipment for groundwater detection, and in particular to a fixed-depth sampling device for groundwater detection. Background Art

[0002] In the development of ecological and environmental protection and water resource security systems, groundwater analysis and testing, as a key technical link, carries the core functions of assessing water quality, monitoring pollution trends, and supporting scientific decision-making. Its test results not only directly influence the formulation of groundwater resource protection strategies and the implementation of environmental remediation projects, but are also closely linked to the safety of public drinking water. Within a complete testing process, groundwater sampling is the primary prerequisite for obtaining valid data. The representativeness and integrity of the sample fundamentally determine the reliability of subsequent test data and the scientific nature of the analytical conclusions.

[0003] In the process of groundwater sampling, a sampling device is required. In the relevant technology, Chinese patent CN119246153B discloses a multifunctional groundwater sampling device, which includes a sampling ring. When washing the well, the sampling ring is placed together with a submersible pump into the groundwater monitoring well, so that while the stagnant water is pumped out by the submersible pump, the impurities generated when the sampling ring and the submersible pump are lowered in the groundwater monitoring well are pumped out; then, after the groundwater is restored and impurities such as silt are settled, the groundwater is sampled in layers through the sampling ring.

[0004] However, existing sampling equipment presents several practical challenges. Groundwater systems exhibit significant physical characteristics of fluidity and continuity. When sampling at a predetermined depth, the extraction of water from the target depth triggers complex hydraulic responses. Driven by the coupling of gravity and water pressure differences, the water above the target depth rapidly replenishes downward. Simultaneously, influenced by the pressure gradient within and outside the monitoring well, the water below also reverses and migrates upward, resulting in a dynamic water displacement phenomenon. This displacement effect directly leads to systematic deviations between the source depth of the actual water samples collected and the predetermined target depth. Consequently, the samples exhibit significant differences in key characteristics such as chemical composition, microbial content, and physical properties compared to the groundwater at the target depth. This depth-induced data distortion can lead to underestimation or overestimation of groundwater contamination, severely compromising the accuracy and reliability of environmental monitoring data. It can even lead to misjudgments and mismatches in groundwater pollution prevention and control strategies, significantly misleading water resource protection and ecological restoration efforts. Summary of the Invention

[0005] Based on this, it is necessary to provide a fixed-depth sampling device for groundwater detection to address the problem of large sampling errors in the current groundwater sampling process.

[0006] The above purpose is achieved through the following technical solutions:

[0007] A fixed-depth sampling device for groundwater detection, the fixed-depth sampling device for groundwater detection is configured to be able to sample groundwater in a detection well; the fixed-depth sampling device for groundwater detection comprises a sampling cylinder and an inflatable member, the sampling cylinder is vertically placed in the detection well during sampling, a sampling port is provided on the sampling cylinder, the sampling port is connected to the detection well; a first one-way valve is provided at the sampling port, and the opening direction of the first one-way valve is configured to be from outside to inside; two base shells are detachably mounted on the sampling cylinder, the two base shells are respectively located on the upper and lower sides of the sampling port, and are connected to each other; an isolation air bag is mounted on each base shell, the isolation air bag is connected to the base shell, and is configured to expand when inflated, and Along the axial direction of the sampling tube, the water body at the sampling port and the water body above the sampling port or the water body below the sampling port are separated; an auxiliary air bag is connected to the base shell, and the auxiliary air bag is located between the two isolation air bags. The auxiliary air bag is configured to expand when inflated to squeeze the water body at the sampling port into the sampling tube through the sampling port; a second one-way valve is provided at the connection between the auxiliary air bag and the base shell, and the second one-way valve is configured to switch from a closed state to an open state when the air pressure value inside the base shell reaches a preset value; the inflatable member is connected to the base shell located above, and is configured to be able to fill gas into the interior of the base shell located above.

[0008] Furthermore, the isolation airbag is arranged obliquely to form an elliptical structure.

[0009] Furthermore, the fixed-depth sampling device for groundwater detection also includes a flattening mechanism, and the flattening mechanism is configured to flatten the isolation airbag along the circumferential direction.

[0010] Furthermore, the flattening mechanism includes a fixed ring frame and a flattening assembly, each of the base shells is fixedly sleeved with the fixed ring frame, and the fixed ring frame is located inside the isolation airbag; each of the fixed ring frames is provided with at least one vent group and at least one flattening assembly, the vent group includes a plurality of vents, the plurality of vents are arranged at intervals along the circumferential direction, and are all connected to the base shell; the flattening assembly includes a rotating ring, the rotating ring is sleeved on the fixed ring frame, and can rotate around the axis of the sampling cylinder, the rotating ring is provided with a plurality of guide blades, a flow channel is formed between adjacent guide blades, and the flow channel and the vent connected; a plurality of fixed tubes are provided on the outer peripheral wall of the rotating ring, and the plurality of fixed tubes are arranged at intervals along the circumferential direction, and the fixed tubes extend in the radial direction and are connected with the flow channel, and each of the fixed tubes is sleeved with a sliding tube, and the sliding tube can elastically slide in the radial direction, and each of the sliding tubes is hinged with a mounting frame, and each of the mounting frames is provided with a flattening roller, and the axis of the flattening roller is parallel to the axis of the sampling tube, and the flattening roller can rotate around its own axis, and is configured to form a rolling fit with the inner side wall of the isolation airbag; an air outlet is provided on each of the sliding tubes, and the air outlet is connected with the fixed tube and the isolation airbag.

[0011] Furthermore, when there are two or more flattening assemblies on the fixed ring frame, each of the isolation airbags is sleeved with at least one elastic ring, and the elastic ring is located between two adjacent flattening assemblies on the same fixed ring frame, and is configured to be able to squeeze the isolation airbag inward to form an annular groove under the action of elasticity.

[0012] Furthermore, a plurality of fixing blocks are provided on the elastic ring, and the plurality of fixing blocks are arranged at intervals along the circumferential direction and are all fixed on the isolation airbag.

[0013] Furthermore, an elastic member is connected between the sliding tube and the fixed tube, and under the action of the elastic member, the sliding tube has a tendency to move outward.

[0014] Furthermore, the elastic member is a compression spring.

[0015] Furthermore, there are multiple sampling ports, which are arranged at intervals along the circumferential direction.

[0016] Furthermore, the inflatable member is an air pump.

[0017] The beneficial effects of the present invention are:

[0018] The fixed-depth sampling device for groundwater detection provided by the present invention has the following steps: first, the fixed-depth sampling device for groundwater detection is placed in the target depth of the detection well, and then gas is filled into the base shell through the inflatable piece. The gas then enters the two isolation air bags and expands the isolation air bags, wherein the upper isolation air bag expands to separate the water body at the sampling port and the water body above the sampling port, and the lower isolation air bag expands to separate the water body at the sampling port and the water body below the sampling port, so that the water body at the target depth can be separated from the upper and lower water bodies, thereby ensuring that the water body entering from the sampling port is always the water body at the target depth, reducing the sampling error; as the gas is continuously filled, the air pressure in the base shell gradually increases. When the air pressure value inside the base shell reaches a preset value, the second one-way valve switches from a closed state to an open state, and the gas then enters the auxiliary air bag and expands the auxiliary air bag, thereby squeezing the water body at the sampling port into the sampling tube through the sampling port and the first one-way valve to complete the sampling.

[0019] Furthermore, by setting the isolation airbag at an angle and forming an elliptical structure, after the isolation airbag is expanded, compared with the annular structure, on the one hand, it can increase the contact area between the isolation airbag and the detection well, which is conducive to improving the sealing effect; on the other hand, it can reduce the local pressure on the isolation airbag, reducing the possibility of damage due to excessive local pressure, and extending the service life of the isolation airbag.

[0020] Furthermore, by setting up a flattening mechanism, during the expansion process of the isolation airbag, the flattening mechanism is used to flatten the isolation airbag along the circumferential direction, which is conducive to more uniform expansion deformation of the isolation airbag and helps to reduce the gap between the isolation airbag and the inner wall of the detection well, thereby further improving the sealing effect between the isolation airbag and the detection well.

[0021] Furthermore, by setting up a flattening mechanism and an elastic ring, during the process of gas filling the isolation airbag, the gas drives the rotating ring to rotate through the guide vanes, and then drives the flattening roller to rotate; during the rotation of the flattening roller, when there are large particulate impurities between the isolation airbag and the detection well, the flattening roller pushes the particulate impurities to move. Since the flattening roller moves along an elliptical trajectory, the flattening roller can push the particulate impurities into the groove, thereby reducing the wear of the particulate impurities on the isolation airbag, which is beneficial to improving the service life of the isolation airbag; at the same time, during the expansion of the isolation airbag, the groove and the inner wall of the detection well jointly surround to form a positive pressure space, which can hinder the communication between the water body at the target depth and the upper and lower water bodies, reducing the impact on the sampling accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic cross-sectional view of the fixed-depth sampling device for groundwater detection provided by an embodiment of the present invention when sampling in a detection well;

[0023] Figure 2 for Figure 1 A schematic diagram of the partially enlarged structure at center A;

[0024] Figure 3 A schematic front view of the structure of a fixed-depth sampling device for groundwater detection provided by an embodiment of the present invention;

[0025] Figure 4 A schematic cross-sectional view of the assembled base shell, isolation airbag, and auxiliary airbag of a fixed-depth sampling device for groundwater detection provided by an embodiment of the present invention;

[0026] Figure 5 A schematic cross-sectional view of a sampling tube of a fixed-depth sampling device for groundwater detection provided by an embodiment of the present invention;

[0027] Figure 6 A schematic diagram of the three-dimensional structure of a flattening mechanism of a fixed-depth sampling device for groundwater detection provided by an embodiment of the present invention;

[0028] Figure 7 A schematic front view of the structure of a flattening mechanism of a fixed-depth sampling device for groundwater detection provided by an embodiment of the present invention;

[0029] Figure 8 for Figure 7 Middle BB section view;

[0030] Figure 9 A schematic diagram of the exploded parts of the flattening mechanism of the fixed-depth sampling device for groundwater detection provided by an embodiment of the present invention;

[0031] Figure 10 for Figure 9 A schematic diagram of the partially enlarged structure at point C in the middle;

[0032] Figure 11 A schematic diagram of the three-dimensional structure of the elastic ring of the fixed-depth sampling equipment for groundwater detection provided by an embodiment of the present invention.

[0033] in:

[0034] 1. Sampling tube; 101. Sampling port; 102. Second flange; 1021. Second bolt hole; 1022. Connecting hole; 103. Sampling tube; 104. Sealing plug;

[0035] 2. Base shell; 201. First flange; 2011. First bolt hole; 202. Communication port;

[0036] 3. Isolation airbag; 301. Groove;

[0037] 4. Auxiliary airbag;

[0038] 5. Second one-way valve; 501. Valve core; 502. Tension spring;

[0039] 6. Flattening mechanism; 601. Fixed ring frame; 6011. Vent; 6012. First mounting ring; 602. Flattening assembly; 6021. Rotating ring; 60211. Second mounting ring; 6022. Guide vane; 6023. Fixed tube; 6024. Sliding tube; 60241. Air outlet; 60242. Articulated frame; 6025. Mounting frame; 6026. Flattening roller; 6027. Compression spring;

[0040] 7. Elastic ring; 701. Fixed block;

[0041] 8. Inspection well. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] The serial numbers assigned to components herein, such as "first," "second," etc., are used solely to distinguish the objects being described and do not convey any sequential or technical meaning. References to "connection" and "coupling" herein, unless otherwise specified, include both direct and indirect connections (couplings). In the description of the present invention, it should be understood that terms such as "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" indicate positions or relationships based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0044] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0045] like Figures 1 to 11As shown, the fixed-depth sampling equipment for groundwater detection provided by one embodiment of the present invention is configured to be able to sample groundwater in the detection well 8, and is configured to include a sampling tube 1 and an inflatable member. The sampling tube 1 is vertically placed in the detection well 8 during sampling. The sampling tube 1 is provided with a sampling port 101, and the sampling port 101 is connected to the detection well 8; a first one-way valve is provided at the sampling port 101, and the opening direction of the first one-way valve is configured to be from outside to inside; two base shells 2 are detachably mounted on the sampling tube 1, and the two base shells 2 are respectively located on the upper and lower sides of the sampling port 101 and are connected to each other; each base shell 2 is mounted with an isolation air bag 3, and the isolation air bag 3 is connected to the base shell 2, and is configured to expand when inflated and move along the sampling tube 1, separates the water body at the sampling port 101 from the water body above the sampling port 101 or the water body below the sampling port 101; an auxiliary air bag 4 is provided on the base shell 2, and the auxiliary air bag 4 is located between the two isolation air bags 3. The auxiliary air bag 4 is configured to expand when inflated, so as to squeeze the water body at the sampling port 101 into the sampling tube 1 through the sampling port 101; a second one-way valve 5 is provided at the connection between the auxiliary air bag 4 and the base shell 2, and the second one-way valve 5 is configured to switch from a closed state to an open state when the air pressure value inside the base shell 2 reaches a preset value; the inflatable member is connected to the base shell 2 located above, and is configured to be able to fill gas into the base shell 2 located above.

[0046] Specifically in this embodiment, the base shell 2 is a cylindrical structure, with the bottom of the upper base shell 2 being open, and the top of the lower base shell 2 being open. To facilitate a detachable connection between the base shell 2 and the sampling tube 1, a first flange 201 is fixedly mounted on the bottom of the upper base shell 2 and the top of the lower base shell 2. A plurality of first bolt holes 2011 are vertically arranged on the surface of the first flange 201, and the plurality of first bolt holes 2011 are arranged at intervals along the circumferential direction. A second flange 102 is fixedly mounted on the middle portion of the sampling tube 1, and a plurality of second bolt holes 1021 are vertically arranged on the surface of the second flange 102, and the plurality of second bolt holes 1021 are arranged at intervals along the circumferential direction.

[0047] During the process of assembling the sampling cylinder 1 and the base shell 2, the lower end of the sampling cylinder 1 is first inserted from top to bottom from the top of the base shell 2 located below into the base shell 2 located below, and then the base shell 2 located above is sleeved on the upper end of the sampling cylinder 1 from top to bottom, and the second flange 102 is clamped in the middle by the first flange 201 on the upper base shell 2 and the first flange 201 on the lower base shell 2, and the second bolt hole 1021 corresponds to the first bolt hole 2011 in position, and then the bolts are respectively passed through the first bolt hole 2011 and the second bolt hole 1021, and then the nut is threadedly sleeved on the other end of the bolt, thereby connecting the sampling cylinder 1 and the two base shells 2 together.

[0048] To facilitate interconnection between the two base shells 2, a plurality of communication holes 1022 are vertically provided on the surface of the second flange 102. These communication holes 1022 are spaced circumferentially and located inboard of the second bolt holes 1021. To facilitate the formation of the sampling port 101, a sampling tube 103 is provided on the circumferential sidewall of the second flange 102. The axis of the sampling tube 103 extends radially along the sampling barrel 1. The sampling port 101 is formed at the orifice of the sampling tube 103. The inner end of the sampling tube 103 extends inwardly through the second flange 102 and the sampling barrel 1, ensuring that water can be introduced into the sampling barrel 1.

[0049] To facilitate the removal of water samples from the sampling cylinder 1, the top of the sampling cylinder 1 is open, and a sealing plug 104 is detachably installed at the top of the sampling cylinder 1. Optionally, the sealing plug 104 can be made of an elastic material such as rubber, and is interference-fitted into the top opening of the sampling cylinder 1 during installation, and achieves a seal between the sealing plug 104 and the sampling cylinder 1 through its own elastic deformation. Optionally, the sealing plug 104 can also be made of a rigid material such as stainless steel, and is threadedly installed into the top opening of the sampling cylinder 1 during installation, and achieves a seal between the sealing plug 1 and the sampling cylinder 1 through a sealing ring.

[0050] The first one-way valve can be set as a swing one-way valve and includes a valve flap, which is hinged in the sampling tube 103 through a pin. When the external pressure is greater than the internal pressure, the valve flap is pushed inward and water enters the sampling tube 1 from the sampling port 101; when the internal pressure is greater than the external pressure, the valve flap is closed under the action of gravity and water pressure to prevent water from flowing back.

[0051] The second one-way valve 5 is configured as a spring-loaded one-way valve and includes a valve core 501 and a tension spring 502. Figure 2 As shown, the valve core 501 is a cylindrical structure and is placed horizontally at the connection point between the auxiliary air bag 4 and the base shell 2. The right end face of the valve core 501 is open and connected to the base shell 2. The left end face of the valve core 501 is sealed and abutted against the base shell 2. A plurality of air guide holes are provided on the circumferential side wall of the left end of the valve core 501 to ensure that when the valve core 501 moves outward, the auxiliary air bag 4 and the base shell 2 can be connected through the air guide holes; the tension spring 502 is inserted horizontally in the valve core 501, and the left end is arranged on the left end face of the valve core 501, and the right end is arranged on the base shell 2. Under the action of the tension spring 502, the valve core 501 has a tendency to move inward, ensuring that the second one-way valve 5 is initially in a closed state.

[0052] The isolation airbag 3 is an annular shell structure and is fixedly mounted on the base shell 2 during installation. To facilitate communication between the base shell 2 and the isolation airbag 3, multiple communication ports 202 are provided on the circumferential sidewall of the base shell 2, and the multiple communication ports 202 are arranged at intervals along the circumference. The auxiliary airbag 4 is a spherical shell structure and is fixedly mounted on the circumferential sidewall of the base shell 2 during installation. The inflatable element is an air pump and is placed at the wellhead of the inspection well 8 during installation. It is connected to the base shell 2 located above via a hose, facilitating the injection of gas into the base shell 2 located above.

[0053] During the sampling process, the fixed-depth sampling equipment for groundwater detection is first lowered to the target depth of the detection well 8 through professional lower equipment, and then the air pump is started. The air pump transports the outside air to the base shell 2 located above through a hose. After the outside air enters the base shell 2 located above, part of it enters the base shell 2 located below through the connecting hole 1022.

[0054] With the continuous injection of air, the two isolation air bags 3 expand under the action of gas pressure. After the upper isolation air bag 3 expands, its outer wall fits tightly against the inner wall of the detection well 8, separating the water body at the sampling port 101 from the water body above; the lower isolation air bag 3 undergoes the same expansion process, separating the water body at the sampling port 101 from the water body below. Through this two-way isolation mechanism, a relatively independent water sample space is constructed around the sampling port 101, ensuring that the water body at the target depth is completely separated from the upper and lower water bodies, effectively avoiding the mixing of water samples caused by the flow and replenishment of the upper and lower water bodies, and reducing the sampling error while ensuring the representativeness and accuracy of the collected water samples.

[0055] As the air pump continues to work, the air in the base shell 2 continues to accumulate, and the air pressure value steadily increases. Under the action of the air pressure, the valve core 501 is pushed outward, and the tension spring 502 is stretched; when the air pressure value inside the base shell 2 reaches the preset value, the valve core 501 moves to the air guide hole and connects with the auxiliary air bag 4, so that the second one-way valve 5 switches from a closed state to an open state. At this time, the air enters the auxiliary air bag 4 driven by the pressure difference, causing it to gradually expand. The expansion of the auxiliary air bag 4 causes the pressure of the water body at the sampling port 101 to gradually increase. Under the action of the external water pressure, the first one-way valve opens, and the water body enters the sampling tube 1 from the sampling port 101, completing the water sample collection work.

[0056] After the sampling is completed, turn off the air pump, and the air in the isolation airbag 3 is discharged through the hose under the action of air pressure, and the volume of the isolation airbag 3 becomes smaller. Then, the fixed-depth sampling equipment for groundwater detection is lifted out of the detection well 8 through professional lower equipment, and then the nut is unscrewed from the bolt, and then the bolt is removed from the first bolt hole 2011 and the second bolt hole 1021. The sampling tube 103 can be removed from the base shell 2, and then the sealing plug 104 can be removed from the sampling cylinder 1. The water sample can be taken out of the sampling cylinder 1 to facilitate the next detection process.

[0057] In a further embodiment, in order to improve the sealing effect between the isolation airbag 3 and the detection well 8, the isolation airbag 3 is arranged to be inclined to form an elliptical structure.

[0058] Specifically in this embodiment, Figure 3 As shown, the isolation airbag 3 is tilted in the upper right direction, so that the upper and lower end surfaces of the isolation airbag 3 are both elliptical, ensuring that an elliptical structure can be formed.

[0059] During use, from the perspective of sealing effect, the elliptical structure is more closely aligned with the contact contour of the wall of the detection well 8 after expansion compared to the annular structure, and the contact area is significantly increased. A larger contact area means increased friction between the two, and at the same time, the gas pressure can act more evenly on the contact surface, thereby forming a more reliable sealing barrier between the isolation airbag 3 and the wall of the detection well 8, which can effectively reduce the existence of gaps and reduce the risk of external water infiltration, ensuring that the target water sample is not contaminated during the collection process and maintaining its representativeness and authenticity.

[0060] In terms of pressure resistance, the inclined elliptical structure changes the pressure conduction path and distribution pattern; when subjected to external water pressure, the elliptical structure can disperse the pressure to various parts more effectively, avoiding the phenomenon of local pressure concentration. This pressure dispersion mechanism makes the pressure on each part of the isolation airbag 3 relatively balanced, significantly improving the tolerance of the isolation airbag 3 in a high-pressure environment, reducing the possibility of damage due to excessive local pressure, and extending the service life of the isolation airbag 3.

[0061] In a further embodiment, in order to further improve the sealing effect between the isolation airbag 3 and the detection well 8, the fixed-depth sampling device for groundwater detection also includes a flattening mechanism 6, which is configured to flatten the isolation airbag 3 along the circumferential direction.

[0062] Specifically in this embodiment, in actual work, due to the characteristics of the airbag material, the uneven distribution of inflation pressure and the irregularity of the inner wall of the detection well 8, the isolation airbag 3 is prone to local over-expansion or under-expansion during the expansion process, resulting in uneven deformation, and then generating a gap between the isolation airbag 3 and the inner wall of the detection well 8, affecting the sealing effect and increasing the risk of water sample contamination; by setting up a flattening mechanism 6, during the inflation process of the isolation airbag 3, the flattening mechanism 6 can apply a circumferential flattening force to the isolation airbag 3 in real time, ensuring that the isolation airbag 3 is subject to uniform external force constraints and guidance during expansion.

[0063] From a mechanical perspective, this uniform circumferential force effectively suppresses excessive expansion of the isolation airbag 3 due to uneven force, prompting the airbag to deform in a more regular and symmetrical manner during expansion. For example, if there are local protrusions or depressions on the inner wall of the detection well 8, without the flattening mechanism 6, the isolation airbag 3 may expand inconsistently at the corresponding locations. However, with the flattening mechanism 6, the airbag can adaptively conform to the contour of the inner wall of the detection well 8 under the regulation of the circumferential force, making the deformation more uniform. This uniform deformation not only helps the isolation airbag 3 fully exert its sealing function, but also reduces the risk of material fatigue and damage caused by local stress concentration, thereby extending the service life of the isolation airbag 3.

[0064] At the same time, the intervention of the flattening mechanism 6 helps reduce the gap between the isolation airbag 3 and the inner wall of the detection well 8. Because the airbag, guided by the flattening mechanism 6, adheres more closely and evenly to the inner wall of the detection well 8, the gap originally caused by uneven expansion is effectively eliminated or reduced. During the actual sampling process, smaller gaps mean a lower probability of leakage, further preventing external water from infiltrating the sampling area, ensuring that the collected water sample is always pure water at the target depth, and guaranteeing sampling accuracy.

[0065] Furthermore, the flattening mechanism 6 is configured to include a fixed ring frame 601 and a flattening assembly 602, each base shell 2 is fixedly sleeved with a fixed ring frame 601, and the fixed ring frame 601 is located inside the isolation airbag 3; each fixed ring frame 601 is provided with at least one vent group and at least one flattening assembly 602, the vent group includes a plurality of vents 6011, and the plurality of vents 6011 are arranged at intervals along the circumferential direction and are all connected to the base shell 2; the flattening assembly 602 includes a rotating ring 6021, the rotating ring 6021 is sleeved on the fixed ring frame 601, and can rotate around the axis of the sampling tube 1, the rotating ring 6021 is provided with a plurality of guide blades 6022, and a flow channel is formed between adjacent guide blades 6022, and the flow channel is connected to the vent 6011; the rotating ring A plurality of fixed tubes 6023 are provided on the outer peripheral wall of 6021. The plurality of fixed tubes 6023 are arranged at intervals along the circumferential direction. The fixed tubes 6023 extend in the radial direction and are connected to the flow channel. A sliding tube 6024 is sleeved on each fixed tube 6023. The sliding tube 6024 can elastically slide in the radial direction. A mounting frame 6025 is hinged on each sliding tube 6024. A flattening roller 6026 is provided on each mounting frame 6025. The axis of the flattening roller 6026 is parallel to the axis of the sampling tube 1. The flattening roller 6026 can rotate around its own axis and is configured to form a rolling fit with the inner wall of the isolation airbag 3; an air outlet 60241 is provided on each sliding tube 6024, and the air outlet 60241 is connected to the fixed tube 6023 and the isolation airbag 3.

[0066] Specifically in this embodiment, the fixed ring frame 601 is annular in structure, with both its upper and lower end faces elliptical. The projection of the fixed ring frame 601 on a vertical plane forms a parallelogram, ensuring compatibility with the elliptical structure of the isolation airbag 3. The multiple vents 6011 in the same vent group are arranged in an elliptical shape, and the multiple communication ports 202 are also arranged in an elliptical shape. The vents 6011 and communication ports 202 are connected in a corresponding manner, ensuring stable gas transmission. The rotating ring 6021 is elliptical in structure, with its end faces parallel to those of the fixed ring frame 601. The cross-section of the rotating ring 6021 is C-shaped, with its opening facing inward. To facilitate the installation of the rotating ring 6021, two first mounting rings 6012 are sleeved on the outer circumferential wall of the fixed ring frame 601. The first mounting ring 6012 is an elliptical structure, and the end face is arranged parallel to the end face of the fixed ring frame 601. The two first mounting rings 6012 are arranged at intervals along the axial direction. Second mounting rings 60211 are arranged on the two spaced-apart inner circumferential walls of the rotating ring 6021. The second mounting ring 60211 is an elliptical structure, and the end face is arranged parallel to the end face of the rotating ring 6021. The second mounting ring 60211 and the rotating ring 6021 form a stepped structure. When the rotating ring 6021 is installed, the two second mounting rings 60211 are clamped by the two first mounting rings 6012 and form a rotating fit to ensure that the rotating ring 6021 can rotate around the axis of the sampling cylinder 1.

[0067] Guide vanes 6022 are tilted and positioned between the two second mounting rings 60211. Multiple guide vanes 6022 are spaced circumferentially, ensuring that when air passes through them, the guide vanes 6022 drive the rotating ring 6021 to rotate. Mounting frame 6025 is C-shaped and, when installed, is positioned vertically with its opening facing outward. To facilitate rotational engagement with flattening roller 6026, first hinge holes are provided on both cantilevered arms of mounting frame 6025. First hinge posts are coaxially positioned on both end surfaces of flattening roller 6026. These first hinge posts are rotatably inserted into the first hinge holes during installation. In order to facilitate the articulated cooperation with the mounting frame 6025, an articulated frame 60242 is fixedly provided at the end of the sliding tube 6024 away from the fixed tube 6023. The articulated frame 60242 is a C-shaped structure and is arranged horizontally during installation with the opening facing outward. Second articulated holes are provided on the two cantilevers of the articulated frame 60242, and two second articulated columns are vertically provided on the left and right side walls of the mounting frame 6025. The second articulated columns are rotated and inserted into the second articulated holes during installation.

[0068] To facilitate radial elastic sliding of the sliding tube 6024, an elastic member is connected between the sliding tube 6024 and the fixed tube 6023. Under the action of the elastic member, the sliding tube 6024 tends to move outward. The elastic member is a compression spring 6027, which is inserted into both the fixed tube 6023 and the sliding tube 6024. The inner end of the compression spring 6027 is fixed to the fixed tube 6023, and the outer end is fixed to the hinge frame 60242. Under the action of the compression spring 6027, the sliding tube 6024 tends to move outward, ensuring that the flattening roller 6026 is pressed against the inner wall of the isolation airbag 3.

[0069] During the process of filling the isolation airbag 3 with air, when the air flows through the guide vane 6022, the guide vane 6022 drives the rotating ring 6021 to rotate under the drive of the air, and the rotating ring 6021 synchronously drives the flattening roller 6026 to rotate through the fixed tube 6023, the sliding tube 6024 and the mounting frame 6025. When the flattening roller 6026 rotates, it can always be set vertically under the articulated cooperation of the mounting frame 6025 and the articulated frame 60242, so that it can fit tightly with the inner wall of the isolation airbag 3, and then can flatten the isolation airbag 3 along the circumferential direction.

[0070] In a further embodiment, when there are two or more flattening assemblies 602 on the fixed ring frame 601, each isolation airbag 3 is sleeved with at least one elastic ring 7, and the elastic ring 7 is located between two adjacent flattening assemblies 602 on the same fixed ring frame 601, and is configured to be able to squeeze the isolation airbag 3 inward to form an annular groove 301 under the action of elasticity.

[0071] Specifically in this embodiment, taking the example of two flattening components 602 on the fixed ring frame 601, there is only one elastic ring 7, which is sleeved on the middle part of the isolation airbag 3. Under the elastic action of the elastic ring 7, the isolation airbag 3 is tightened inward to form a ring-shaped groove 301.

[0072] During use, when air flows through the guide blade 6022, the guide blade 6022 drives the rotating ring 6021 to rotate under the drive of the air, and the rotating ring 6021 synchronously drives the flattening roller 6026 to rotate; during the rotation of the flattening roller 6026, when there are large granular impurities between the isolation airbag 3 and the detection well 8, the flattening roller 6026 pushes the granular impurities to move circumferentially. Since the flattening roller 6026 moves along an elliptical trajectory, the flattening roller 6026 and the granular impurities are gradually dislocated in the vertical direction; when the flattening roller 6026 and the granular impurities are completely staggered, the granular impurities fall into the groove 301 under the action of gravity, thereby reducing the direct friction between the isolation airbag 3 and the granular impurities during the continuous expansion process, and then reducing the wear of the isolation airbag 3, which helps to extend the service life of the isolation airbag 3.

[0073] At the same time, during the expansion of the isolation airbag 3, the groove 301 formed by the elastic ring 7 and the inner wall of the detection well 8 together form a relatively closed positive pressure space. The formation of this positive pressure space is based on the principle of fluid mechanics, that is, as the isolation airbag 3 continues to expand, the volume of the groove 301 area decreases and the pressure increases. Because the pressure in this area is higher than the pressure of the surrounding water body, a pressure difference is formed. This pressure difference effectively hinders the communication between the water body at the target depth and the upper and lower water bodies. For example, when the upper water body attempts to flow downward, the pressure in the positive pressure space will form a reverse resistance to it, preventing it from flowing into the target water sample area; when the lower water body flows upward, it will also be blocked by the positive pressure space, thereby further ensuring the purity of the target water sample, while effectively reducing the impact of the upper and lower water bodies on the sampling accuracy, ensuring that the collected water sample can truly and accurately reflect the water quality of the groundwater at the target depth.

[0074] In a further embodiment, in order to ensure that the elastic ring 7 can always be sleeved on the isolation airbag 3 to avoid loss, a plurality of fixing blocks 701 are provided on the elastic ring 7. The plurality of fixing blocks 701 are arranged at intervals along the circumference and are all fixed on the isolation airbag 3.

[0075] In other embodiments, in order to improve sampling efficiency, there are multiple sampling ports 101 , which are arranged at intervals along the circumference.

[0076] Specifically in this embodiment, to facilitate the formation of multiple sampling ports 101, a corresponding number of sampling tubes 103 are provided, which are spaced apart along the circumference, and a first one-way valve is inserted at each sampling port 101. In this way, during sampling, the multiple sampling ports 101 can all introduce water of the target depth into the sampling cylinder 1, thereby improving sampling efficiency.

[0077] In other embodiments, to improve sampling efficiency, multiple auxiliary airbags 4 are provided, divided into two groups. One group of auxiliary airbags 4 is provided on the circumferential sidewall of the upper base shell 2 and spaced circumferentially, while the other group of auxiliary airbags 4 is provided on the circumferential sidewall of the lower base shell 2 and spaced circumferentially. Thus, during sampling, air can enter the multiple auxiliary airbags 4, thereby increasing the rate of increase in water pressure at the sampling port 101 and generating a greater pressure differential across the first one-way valve. Under the greater pressure differential, the rate at which water enters the sampling tube 1 from the sampling port 101 increases, thereby improving sampling efficiency.

[0078] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0079] The above-described embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that variations and modifications are possible without departing from the scope of the present invention, and such variations and modifications are fully within the scope of protection of the present invention.

Claims

1. A fixed-depth sampling device for groundwater detection, configured to sample groundwater in a detection well; characterized in that: The sampling tube comprises a sampling tube, an inflating member and a flattening mechanism. The sampling tube is placed vertically in the detection well during sampling. A sampling port is provided on the sampling tube, and the sampling port is connected to the detection well. A first one-way valve is provided at the sampling port, and the opening direction of the first one-way valve is configured to be from outside to inside. Two base shells are detachably mounted on the sampling tube, and the two base shells are respectively located at the upper and lower sides of the sampling port and are connected to each other. An isolation air bag is mounted on each base shell, and the isolation air bag is connected to the base shell and is configured to expand when inflated, and to separate the water at the sampling port and the water at the sampling port along the axial direction of the sampling tube. The water body above the sampling port or the water body below the sampling port is separated; an auxiliary air bag is provided on the base shell, the auxiliary air bag is located between the two isolation air bags, and the auxiliary air bag is configured to expand when inflated to squeeze the water body at the sampling port into the sampling tube through the sampling port; a second one-way valve is provided at the connection between the auxiliary air bag and the base shell, and the second one-way valve is configured to switch from a closed state to an open state when the air pressure value inside the base shell reaches a preset value; the inflatable member is connected to the base shell located above, and is configured to be able to inflate gas into the interior of the base shell located above; The isolation airbag is tilted and forms an elliptical structure; The flattening mechanism is configured to flatten the isolation airbag along the circumferential direction; the flattening mechanism includes a fixed ring frame and a flattening assembly, each base shell is fixedly sleeved with a fixed ring frame, and the fixed ring frame is located inside the isolation airbag; each fixed ring frame is provided with at least one vent group and at least one flattening assembly, the vent group includes a plurality of vents, and the plurality of vents are arranged at intervals along the circumferential direction and are all connected to the base shell; the flattening assembly includes a rotating ring, the rotating ring is sleeved on the fixed ring frame, and can rotate around the axis of the sampling tube, and a plurality of guide blades are provided on the rotating ring, and a flow channel is formed between adjacent guide blades, and the flow channel The duct is connected to the air vent; a plurality of fixed tubes are provided on the outer peripheral wall of the rotating ring, and the plurality of fixed tubes are arranged at intervals along the circumferential direction, the fixed tubes extend in the radial direction, and are connected to the flow channel, each fixed tube is sleeved with a sliding tube, and the sliding tube can slide elastically in the radial direction, each sliding tube is hinged with a mounting frame, and each mounting frame is provided with a flattening roller, the axis of the flattening roller is parallel to the axis of the sampling cylinder, the flattening roller can rotate around its own axis, and is configured to form a rolling fit with the inner side wall of the isolation airbag; an air outlet is provided on each sliding tube, and the air outlet is connected to the fixed tube and the isolation airbag; When there are two or more flattening assemblies on the fixed ring frame, each isolation airbag is sleeved with at least one elastic ring, which is located between two adjacent flattening assemblies on the same fixed ring frame and is configured to be able to squeeze the isolation airbag inward to form an annular groove under the action of elasticity, so that during the expansion of the isolation airbag, the groove and the inner wall of the detection well jointly form a relatively closed positive pressure space. At the same time, the flattening roller pushes the granular impurities to move circumferentially. Since the flattening roller moves along an elliptical trajectory, the flattening roller and the granular impurities are gradually dislocated in the vertical direction. When the flattening roller and the granular impurities are completely dislocated, the granular impurities fall into the groove under the action of gravity.

2. The fixed-depth sampling equipment for groundwater detection according to claim 1, characterized in that: A plurality of fixing blocks are provided on the elastic ring, and the plurality of fixing blocks are arranged at intervals along the circumferential direction and are all fixed on the isolation airbag.

3. The fixed-depth sampling equipment for groundwater detection according to claim 1, characterized in that: An elastic member is connected between the sliding tube and the fixed tube, and the sliding tube has a tendency to move outward under the action of the elastic member.

4. The fixed-depth sampling equipment for groundwater detection according to claim 3, characterized in that: The elastic member is a compression spring.

5. The fixed-depth sampling equipment for groundwater detection according to claim 1, characterized in that: There are multiple sampling ports, which are spaced apart along the circumference.

6. The fixed-depth sampling equipment for groundwater detection according to claim 1, characterized in that: The inflatable component is an air pump.

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