A fixed-depth sampling device for NAPLs-contaminated groundwater

Abstract

The present invention relates to the technical field of groundwater sampling and detection, and in particular to a fixed-depth sampling device for NAPLs-contaminated groundwater; the device can accurately sample upper and lower water samples of a fixed-depth aquifer, effectively reduce disturbance of the aquifer, improve water sampling accuracy, and reduce errors in measuring the volume of contaminated groundwater; the device comprises a monitoring well pipe, a sampling pipe section arranged at the monitoring well pipe, and a sampling mechanism for sampling water at a fixed depth; the self-closing plugging member comprises a ring frame, a plurality of sampling holes equidistantly distributed circumferentially around the ring frame, and a first self-closing valve installed in the sampling hole; the sampling mechanism comprises a traveling mechanism slidably installed in the monitoring well pipe, a guide frame installed at the bottom of the traveling mechanism and arranged corresponding to the sampling holes, a plurality of samplers, and a synchronous pusher; the sampler comprises a sampling bottle, a valve component installed at the bottle mouth of the sampling bottle, a sampling tube installed on the valve component, and a second self-closing valve installed in the sampling tube.

Description

Technical Field

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

[0002] Groundwater contamination is often hidden, requiring sampling and testing to determine the extent of groundwater contamination. Non-aqueous phase liquids (NAPLs) are common contaminants in groundwater at organically contaminated sites. When NAPLs enter aquifers, contaminants with a density lower than water, such as light non-aqueous phase liquids (LNAPLs), such as petroleum products (gasoline, diesel, kerosene), and organic solvents (benzene, toluene, xylene, and ethylbenzene), tend to float on the surface of the groundwater and accumulate near the water table in the upper part of the aquifer. Meanwhile, heavier contaminants, such as heavy non-aqueous phase liquids (DNAPLs), such as chlorinated solvents (trichloroethylene (TCE), tetrachloroethylene (PCE), and polychlorinated biphenyls (PCBs), coal tar, and petroleum derivatives, tend to migrate vertically downward, accumulating at the aquifer floor and forming pockets of varying sizes in the groundwater.

[0003] The accuracy of surveys investigating NAPLs contamination concentrations and spatial distribution is directly related to the effectiveness assessment and decision-making support for contaminated site remediation. Currently, groundwater sampling primarily involves sampling with a bailer tube or pumping water down a monitoring well. These sampling methods and samplers collect mostly surface water samples or mixed upper and lower layer water samples, which may not represent the true concentration of NAPLs in groundwater. This can lead to NAPLs contaminants being overlooked or the severity of NAPLs contamination being overestimated. Furthermore, the sampling depth of groundwater NAPLs directly affects the calculation of NAPLs contamination volume. Therefore, LNAPLs and DNAPLs should be sampled in layers at specific depths to ensure that pollutants at different depths are accurately collected and to truly and objectively reflect the NAPLs contamination status.

[0004] For example, Chinese invention patent CN118624295B discloses a groundwater sampling device for groundwater surveys at different depths. The device comprises a ring frame, a mounting base, a sampling tube, a position limiting assembly, an adjustment assembly, and a pull-out frame. This device can sequentially sample at multiple depths, is easy to operate, and improves on-site sampling efficiency.

[0005] However, when the inventors implemented this device, they discovered the following drawbacks: LNAPLs pollutants float in the upper part of the underground aquifer, while DNAPLs pollutants settle in the lower part of the underground aquifer. Using the aforementioned sampling device to take samples can easily cause disturbances in the aquifer, causing LNAPLs and DNAPLs pollutants to mix with the water, resulting in distorted water sample data and difficulty reflecting the true contamination of the groundwater. Summary of the Invention

[0006] (1) Technical problems solved

[0007] In response to the shortcomings of the existing technology, the present invention provides a fixed-depth sampling device for NAPLs-contaminated groundwater, which can accurately sample the upper and lower water samples of a fixed-depth aquifer, effectively reduce the disturbance of the aquifer, improve the sampling accuracy of water samples, and reduce the error in the measurement of the contaminated groundwater volume.

[0008] (2) Technical solution

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a fixed-depth sampling device for NAPLs-contaminated groundwater, comprising a monitoring well pipe, a sampling pipe section arranged at the monitoring well pipe, and a sampling mechanism for fixed-depth water sampling, wherein the sampling pipe section is located in the aquifer to be sampled, and a plurality of self-closing plugging members arranged equidistantly from top to bottom are provided in the sampling pipe section, wherein the self-closing plugging members comprise a ring frame, a plurality of sampling holes equidistantly distributed circumferentially around the ring frame, and a first self-closing valve installed in the sampling hole; the sampling mechanism comprises a traveling mechanism slidably installed in the monitoring well pipe, a guide frame installed at the bottom of the traveling mechanism and arranged corresponding to the sampling holes, a plurality of samplers and a plurality of self-closing valves installed in the sampling holes. The synchronous pusher comprises a sampling bottle, a valve member installed at the mouth of the sampling bottle, a sampling tube installed on the valve member and a second self-closing valve installed in the sampling tube. The guide frame is provided with a guide hole arranged corresponding to the sampling hole, and the sampling tube is slidably installed in the guide hole. The synchronous pusher comprises a driving motor fixedly installed on the walking mechanism, a rotating disk fixedly installed at the output end of the driving motor and a plurality of driving blocks circumferentially arranged on the outer wall of the rotating disk. The driving block is used to push the sampling tube on the corresponding sampler along the guide hole to the side away from the center of the rotating disk. A first spring is sleeved on the valve member, and the valve member is elastically connected to the guide frame through the first spring. Furthermore, the bottom of the monitoring well pipe is sealed, and a closed cavity with an upper opening is formed in the monitoring well pipe to prevent groundwater from entering the monitoring well pipe; the height of the sampling pipe section is greater than the depth of the aquifer to meet the sampling requirements of water samples from the upper, middle and lower layers of the entire aquifer; the sampling hole adopts a cylindrical hole, and the central axis of the sampling hole coincides with the corresponding diameter of the ring frame; the sampling tube is connected to the interior of the sampling bottle through a valve member, and the first self-closing valve and the second self-closing valve are normally closed valves, and the first self-closing valve and the second self-closing valve can adopt solenoid valves or other electric control valves with self-starting effects; the walking mechanism can be self-contained A walker is provided to enable the walking mechanism to move up and down along the inner wall of the monitoring well pipe, and the walking mechanism can also be driven to move up and down along the inner wall of the monitoring well pipe by a lifting tractor; the driving block is in active contact with the valve member on the corresponding sampler, one end of the driving block is inclined toward the center of the rotating disk, and the other end of the driving block is inclined away from the center of the rotating disk, and an acute angle of 60°-80° is formed between the central axis of the sampling tube and the driving block; one end of the first spring is connected to the guide frame, and the other end of the first spring is connected to the valve member; the outer wall of the sampling tube and the inner wall of the guide hole and the inner wall of the sampling hole are sealed by rubber or other fillers.

[0010] Preferably, the first self-closing valve and the second self-closing valve both include a valve body, a valve stem, a valve plug fixedly connected to the valve stem, and a second spring sleeved on the valve stem. The valve stem is slidably installed in the valve body. The valve stem is elastically connected to the valve body through the second spring. When the second spring is in an extended state, the valve plug blocks the inside of the valve body. The first self-closing valve and the second self-closing valve are arranged in a mirror image.

[0011] The lifting mechanism is a kind of lifting mechanism that is made up of the lifting mechanism and the lifting mechanism of lifting mechanism, and the lifting mechanism is a kind of lifting mechanism of lifting mechanism, and the lifting mechanism of lifting mechanism is a kind of lifting mechanism of lifting mechanism. Furthermore, the connecting rods are threadedly connected, and a group of connecting rods on the upper part are threadedly connected to the rotary card. The rotary driver adopts a speed-regulating motor that can rotate in forward and reverse directions. The rotary driver is connected to the rotary card through transmission parts such as gears or chains; the lifting driver can adopt a telescopic cylinder, or other equivalent parts that can drive the lifting seat to rise and fall. The feeder is preferably a threaded screw, and can also adopt other equivalent parts such as a telescopic cylinder that can drive the arc-shaped clamping arm to feed. The connecting rods are standard lengths, such as 5cm, 10cm, 20cm, 30cm, 50cm, etc., and connecting rods of appropriate specifications and lengths can be selected according to the sampling depth. Connecting rods of different sizes can be used in combination to effectively control the descent depth of the sampling mechanism.

[0012] Preferably, it also includes multiple first connecting pipes, second connecting pipes and water pumps, the valve component is an electromagnetic three-way valve, the horizontal end of the electromagnetic three-way valve is connected to the sampling tube, the bottom end of the electromagnetic three-way valve is connected to the inside of the sampling bottle, one end of the first connecting pipe is connected to the top end of the corresponding electromagnetic three-way valve, the connecting rod and the middle part of the rotary card are both provided with a hollow channel, the other end of the first connecting pipe extends into the hollow channel of a group of connecting rods near the walking mechanism, one end of the second connecting pipe is rotatably sealed and connected to the hollow channel on the rotary card, and the other end of the second connecting pipe is connected to the input end of the water pump; further, the first connecting pipe and the second connecting pipe are both flexible and plastic tubes lined with steel wire to avoid excessive deformation under the action of the negative pressure of the water pump and affecting the normal passage of water flow, so as to avoid the first connecting pipe interfering with the movement of the valve component, and the second connecting pipe is rotatably sealed and connected to the hollow channel on the rotary card through a rotary sealing joint; the interior of the sampling bottle is vacuumed.

[0013] Preferably, it also includes a support frame installed on the frame and a guide wheel rotatably installed on the top of the support frame, a hollow roller is rotatably installed on the frame, the second connecting pipe is wrapped around the hollow roller after passing the guide wheel, the output end of the second connecting pipe extends into the hollow roller, the input end of the water pump extends into the hollow roller, and a servo motor that provides power for the rotation of the hollow roller is installed on the frame; further, the input end of the water pump is connected to the interior of the hollow roller through a rotating sealing joint.

[0014] Preferably, the inner wall of the sampling tube section is provided with a plurality of equidistant and evenly distributed annular cavities from top to bottom, the sampling tube section is provided with a plurality of infiltration holes connected to the annular cavities, the ring frame is rotatably installed in the annular cavity, the plurality of sampling holes on the ring frame are arranged corresponding to the plurality of infiltration holes, a infiltration net is installed in the infiltration holes, the outer arm of the ring frame is provided with a plurality of circumferentially evenly distributed sealing parts, an arc-shaped infiltration buffer cavity is formed between the sealing parts, the outer wall of the ring frame and the inner wall of the annular cavity; further, the ring frame is inertially connected to the inner wall of the annular cavity to prevent the ring frame from rotating on its own; the contact point between the ring frame and the annular cavity is connected in a rotating seal by a filler or the like, and the filler can also prevent the ring frame from rotating on its own.

[0015] Preferably, the walking mechanism includes a polygonal frame and elastic centering supports equidistantly distributed along the outer wall of the polygonal frame. The elastic centering supports include two symmetrically arranged legs hinged to the polygonal frame, rollers rotatably mounted on the legs, and connecting springs. The two legs are elastically connected by the connecting spring; further, the two ends of the connecting spring are respectively hinged to the two legs.

[0016] Preferably, a ball is rotatably mounted on the valve member, and the drive block is movably connected to the valve member via the ball.

[0017] Preferably, the monitoring well pipe includes a plurality of pipe sections that are detachably connected at the ends, and a detection probe is installed at the valve plug on the first self-closing valve; further, the detection probe is preferably a resistance detection probe, and chemical parameter sensors with different functions can also be installed, such as pH sensors, ion selective electrodes, heavy metal sensors, etc.; the detection end of the detection probe is exposed from the valve plug.

[0018] (3) Beneficial effects

[0019] Compared with the prior art, the present invention provides a fixed-depth sampling device for NAPLs-contaminated groundwater, which has the following beneficial effects: the fixed-depth sampling device for NAPLs-contaminated groundwater, according to the depth and thickness of the aquifer surveyed in the early stage, drives a monitoring well pipe into the ground through an external drill, the sampling pipe section is located in the aquifer, and the walking mechanism moves down along the inner wall of the monitoring well pipe to the self-closing plugging piece corresponding to the upper, middle or lower part of the required sampling water layer, the driving motor drives the rotating disk to rotate, the rotating disk drives the driving block to move, the driving block pushes the valve member and the sampling tube to move outward along the corresponding guide hole until the sampling tube extends into the sampling hole, the first self-closing valve and the second self-closing valve are opened, and the sampling hole is connected to the water of the corresponding water layer , the water of the corresponding water layer flows into the sampling bottle through the sampling hole, sampling tube and valve body; the upper and lower water samples of the fixed depth aquifer can be accurately sampled in layers, effectively reducing the disturbance of the aquifer and avoiding the re-migration of NAPLs during the sampling process; the LNAPLs in the upper part of the aquifer and the DNAPLs in the lower part are prevented from mixing with the water in the aquifer, thereby improving the accuracy of water sampling and making the samples more representative; the dilution of pollutant concentration or phase confusion can be avoided, and the contaminated layer can be accurately located; the vertical distribution characteristics of pollutants can be accurately captured by matching the physical and chemical properties of NAPLs with hydrogeological conditions, and combined with layered data collection, the reliability of NAPLs pollution range definition and remediation engineering quantity calculation can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0021] Figure 2 It is a front planar structural schematic diagram of the present invention;

[0022] Figure 3 The present invention Figure 2 Schematic diagram of the cross-section structure at AA in the middle;

[0023] Figure 4 The present invention Figure 3 Schematic diagram of the cross-section structure at the middle BB;

[0024] Figure 5 The present invention Figure 3 A schematic diagram of the partially enlarged structure at point C in the middle;

[0025] Figure 6 The present invention Figure 3 The schematic diagram of the local enlarged structure at D in the middle;

[0026] Figure 7 The present invention Figure 4 Schematic diagram of the local enlarged structure at E in the middle;

[0027] Figure 8 This is a schematic diagram of the three-dimensional structure of the self-closing blocking member of the present invention;

[0028] Figure 9 It is a schematic diagram of the three-dimensional structure of the sampling mechanism of the present invention;

[0029] Figure 10 The present invention Figure 9 The schematic diagram of the partially enlarged structure at F in the middle;

[0030] Markings in the accompanying drawings: 1, sampling tube section; 2, ring stand; 3, sampling hole; 4, first self-closing valve; 5, guide frame; 6, sampling bottle; 7, sampling tube; 8, second self-closing valve; 9, guide hole; 10, driving motor; 11, rotating disk; 12, driving block; 13, first spring; 14, valve body; 15, valve stem; 16, valve plug; 17, second spring; 18, frame; 19, lifting seat; 20, rotary card; 21, rotary drive; 22, connecting rod; 23, arc Clamping arm; 24. Feeder; 25. Lifting drive; 26. First connecting pipe; 27. Second connecting pipe; 28. Water pump; 29. ​​Solenoid three-way valve; 30. Hollow channel; 31. Support frame; 32. Guide wheel; 33. Hollow roller; 34. Filtration hole; 35. Filtration net; 36. Sealing part; 37. Arc-shaped filtration buffer chamber; 38. Polygonal frame; 39. Support leg; 40. Roller; 41. Connecting spring; 42. Ball; 43. Pipe joint; 44. Detection probe. DETAILED DESCRIPTION

[0031] To help those skilled in the art better understand the invention, the following will provide a clear and complete description of the technical solutions in the embodiments of the invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the invention, not all of them. All other embodiments derived by those skilled in the art based on the embodiments of the invention without creative effort should fall within the scope of protection for the invention.

[0032] As described in the background technology, a groundwater sampling device for groundwater surveys at different depths is used. Most of the contaminated water samples in the groundwater layer are organic matter. Organic pollutants are divided into light non-aqueous phase liquids (LNAPLs) and heavy non-aqueous phase liquids (DNAPLs). Light non-aqueous phase liquid pollutants float on the upper part of the underground aquifer, while heavy non-aqueous phase liquid pollutants settle in the lower part of the underground aquifer. Light non-aqueous phase liquid pollutants and heavy non-aqueous phase liquid pollutants are important indicators for measuring groundwater pollution. When sampling, the aquifer is easily disturbed, and the light non-aqueous phase liquid and heavy non-aqueous phase liquid pollutants mix with water, causing distortion of water sample data and making it difficult to reflect the actual pollution situation of the groundwater.

[0033] In order to solve this technical problem, the present invention provides a NAPLs-contaminated groundwater fixed-depth sampling device, which is used for stratified sampling of groundwater aquifers.

[0034] It should be noted that, in the absence of conflict, the embodiments of the invention and the features and technical solutions in the embodiments can be combined with each other.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. Example 1

[0036] Please refer to Figures 1-4 as well as Figures 6-10, a NAPLs contaminated groundwater fixed-depth sampling device specifically comprises: a monitoring well pipe, a sampling pipe section 1 arranged at the monitoring well pipe and a sampling mechanism for fixed-depth water sampling, the sampling pipe section 1 is located in the aquifer to be sampled, and a plurality of self-closing plugging members are arranged equidistantly from top to bottom in the sampling pipe section 1, the self-closing plugging member comprises a ring frame 2, a plurality of sampling holes 3 equidistantly distributed circumferentially around the ring frame 2 and a first self-closing valve 4 installed in the sampling hole 3; the sampling mechanism comprises a walking mechanism slidably installed in the monitoring well pipe, a guide frame 5 installed at the bottom of the walking mechanism and arranged corresponding to the sampling holes 3, a plurality of samplers and a synchronous pusher, the sampler comprises a sampling bottle 6, A valve component is installed at the mouth of the sampling bottle 6, a sampling tube 7 is installed on the valve component, and a second self-closing valve 8 is installed in the sampling tube 7. A guide hole 9 corresponding to the sampling hole 3 is provided on the guide frame 5. The sampling tube 7 is slidably installed in the guide hole 9. The synchronous pusher includes a drive motor 10 fixedly installed on the walking mechanism, a rotating disk 11 fixedly installed on the output end of the drive motor 10, and a plurality of drive blocks 12 circumferentially arranged on the outer wall of the rotating disk 11. The drive block 12 is used to push the sampling tube 7 on the corresponding sampler along the guide hole 9 to feed away from the center of the rotating disk 11. A first spring 13 is sleeved on the valve component, and the valve component is elastically connected to the guide frame 5 through the first spring 13. Furthermore, the bottom of the monitoring well pipe is sealed, and a closed cavity with an upper opening is formed in the monitoring well pipe to prevent groundwater from entering the monitoring well pipe; the height of the sampling pipe section 1 is greater than the depth of the aquifer to meet the sampling requirements of water samples from the upper, middle and lower layers of the entire aquifer; the sampling hole 3 adopts a cylindrical hole, and the central axis of the sampling hole 3 coincides with the corresponding diameter of the ring frame 2; the sampling tube 7 is connected to the inside of the sampling bottle 6 through a valve member, and the first self-closing valve 4 and the second self-closing valve 8 are normally closed valves. The first self-closing valve 4 and the second self-closing valve 8 can adopt solenoid valves or other other electrically controlled valves with self-starting effects; the walking mechanism can be equipped with a walker to enable the walking mechanism to move up and down along the inner wall of the monitoring well pipe, or it can be driven by a lifting tractor to move up and down along the inner wall of the monitoring well pipe; the driving block 12 is in active contact with the valve member on the corresponding sampler, and one end of the driving block 12 moves closer to the rotating disk 1 1, the other end of the driving block 12 is tilted away from the center of the rotating disk 11, and the central axis of the sampling tube 7 and the driving block 12 form an acute angle of 60°-80°; one end of the first spring 13 is connected to the guide frame 5, and the other end of the first spring 13 is connected to the valve member. When the driving block 12 is out of contact with the valve member, the first spring 13 can cause the valve member and the sampling tube 7 to reset themselves, so that the sampling tube 7 moves out of the sampling hole 3 by itself; the outer wall of the sampling tube 7 and the inner wall of the guide hole 9 and the inner wall of the sampling hole 3 are sealed by rubber or other fillers; it should be noted that marks corresponding to multiple sampling holes 3 are provided on the upper part of the monitoring well pipe. After the guide hole 9 on the sampling mechanism is aligned with the mark, it moves downward along the inner wall of the monitoring well pipe. The distance the sampling mechanism moves downward is the position of the sampling hole 3 at the corresponding depth sampling water layer, so as to ensure that the sampling hole 3 and the guide hole 9 are smoothly aligned.

[0037] For details, please refer to Figure 6 and Figure 9 The walking mechanism includes a polygonal frame 38 and elastic centering supports equidistantly distributed along the outer wall of the polygonal frame 38. The elastic centering supports include two symmetrically arranged legs 39 hinged to the polygonal frame 38, a roller 40 rotatably mounted on the legs 39, and a connecting spring 41. The two legs 39 are elastically connected by the connecting spring 41; further, the two ends of the connecting spring 41 are respectively hinged to the two legs 39.

[0038] For details, please refer to Figure 4 A ball bearing 42 is rotatably mounted on the valve member, and the drive block 12 is movably connected to the valve member via the ball bearing 42.

[0039] For details, please refer to Figure 7 The first self-closing valve 4 and the second self-closing valve 8 both include a valve body 14, a valve stem 15, a valve plug 16 fixedly connected to the valve stem 15, and a second spring 17 sleeved on the valve stem 15. The valve stem 15 is slidably installed in the valve body 14. The valve stem 15 is elastically connected to the valve body 14 through the second spring 17. When the second spring 17 is in an extended state, the valve plug 16 blocks the inside of the valve body 14. The first self-closing valve 4 and the second self-closing valve 8 are arranged in a mirror image.

[0040] The NAPLs-contaminated groundwater fixed-depth sampling device provided in this embodiment has the two legs 39 moving toward each other under the action of the connecting spring 41. Under the action of each elastic centering support, the vertical center axis of the polygonal frame 38 coincides with the center axis of the monitoring well pipe, and at the same time can improve the stability of the walking mechanism moving up and down along the inner wall of the monitoring well pipe, avoiding the shaking of the polygonal frame 38; and the ball 42 can realize rolling contact between the driving block 12 and the valve component, effectively reducing the friction between the driving block 12 and the valve component, improving the transmission efficiency between the driving block 12 and the valve component, and reducing the output power of the driving motor 10.

[0041] After the sampling tube 7 is extended into the sampling hole 3, the valve stems 15 on the first self-closing valve 4 and the second self-closing valve 8 contact each other, the second spring 17 is compressed, and the corresponding valve plug 16 disengages from the blockage of the valve body 14, so that the sampling tube 7 and the sampling hole 3 are connected to each other; in this way, the mechanical opening of the first self-closing valve 4 and the second self-closing valve 8 can be achieved. When the sampling tube 7 is removed from the sampling hole 3, under the action of the second spring 17, the valve plug 16 quickly closes the valve body 14. Under the action of the first self-closing valve 4, during the process of lowering the monitoring well pipe, the water in the aquifer can be effectively prevented from entering the interior of the monitoring well pipe, so as to avoid mixing and contact between water layers of different depths in the aquifer, thereby ensuring the sampling accuracy of the water sample.

[0042] In another embodiment, there may be multiple sampling pipe sections 1, and the multiple sampling pipe sections 1 are respectively located in aquifers at different depths, so as to achieve water sampling from aquifers at different depths.

[0043] The NAPLs contaminated groundwater fixed depth sampling device provided in Example 1 is further optimized. For details, please refer to Figure 1-Figure 3 as well as Figure 5-Figure 6 , also includes a lifting tractor for driving the walking mechanism to move up and down, the lifting tractor includes a frame 18, a lifting seat 19 slidably mounted on the frame 18, a rotary card 20 rotatably mounted on the lifting seat 19, a rotary driver 21 that provides power for the rotation of the rotary card 20, a traction rod and a clamp, one end of the traction rod is fixedly connected to the upper part of the walking mechanism, and the other end of the traction rod is detachably connected to the rotary card 20. The traction rod includes a plurality of connecting rods 22 that are detachably connected to each other at the head and tail. The clamp includes two symmetrically arranged clamping members, the clamping member includes an arc-shaped clamping arm 23 slidably mounted on the frame 18 and a feeder 24 that provides power for the sliding of the arc-shaped clamping arm 23. A lifting driver 25 that provides power for the lifting seat 19 to slide up and down along the frame 18 is installed on the frame 18 ; Further, the connecting rods 22 are threadedly connected, and the upper group of connecting rods 22 is threadedly connected to the rotary card device 20. The rotation driver 21 adopts a speed-regulating motor that can rotate forward and reverse, and the rotation driver 21 is connected to the rotary card device 20 through a transmission member such as a gear or a chain; the lifting driver 25 can adopt a telescopic cylinder, or other equivalent parts that can drive the lifting seat 19 to rise and fall. The feeder 24 is preferably a threaded screw, or other equivalent parts such as a telescopic cylinder that can drive the arc-shaped clamping arm 23 to feed. The connecting rod 22 is a standard length, such as 5cm, 10cm, 20cm, 30cm, 50cm, etc., and the connecting rod 22 of appropriate length can be selected according to the sampling depth. Connecting rods 22 of different sizes can be used in combination to effectively control the descent depth of the sampling mechanism.

[0044] By starting the feeder 24, a group of connecting rods 22 connected to the walking mechanism are clamped between the two arc-shaped clamping arms 23, and the other connecting rod 22 is placed vertically on the upper part of the clamped connecting rod 22. The lifting driver 25 drives the lifting seat 19 to move down the upper group of connecting rods 22 and clamp the upper part into the rotary clamp 20. The rotary driver 21 drives the rotary clamp 20 to rotate, so that the two connecting rods 22 are screwed together. According to the depth of the water layer to be sampled, appropriate specifications and quantity of connecting rods 22 are selected, so that the descending distance of the sampling mechanism can be effectively controlled. Similarly, after the sampling is completed, the connecting rods 22 can be removed one by one according to the above principle until the sampling bottle 6 is completely exposed from the top of the monitoring well pipe.

[0045] For details, please refer to Figure 2-Figure 7 and Figure 9-10, also includes a plurality of first connecting pipes 26, second connecting pipes 27 and a water pump 28, the valve member is an electromagnetic three-way valve 29, the horizontal end of the electromagnetic three-way valve 29 is connected to the sampling tube 7, the bottom end of the electromagnetic three-way valve 29 is connected to the interior of the sampling bottle 6, one end of the first connecting pipe 26 is connected to the top end of the corresponding electromagnetic three-way valve 29, the middle part of the connecting rod 22 and the rotary card device 20 are both provided with a hollow channel 30, the other end of the first connecting pipe 26 extends into the hollow channel 30 of a group of connecting rods 22 near the walking mechanism, and one end of the second connecting pipe 27 is connected to the hollow channel 30 of the connecting rod 22 near the walking mechanism. The hollow channel 30 on the rotary card device 20 is rotatably sealed and connected, and the other end of the second connecting pipe 27 is connected to the input end of the water pump 28; further, the first connecting pipe 26 and the second connecting pipe 27 are both flexible plastic pipes lined with steel wire to avoid excessive deformation under the negative pressure of the water pump 28 and affecting the normal passage of water flow, so as to avoid the first connecting pipe 26 interfering with the movement of the valve member. The second connecting pipe 27 is rotatably sealed and connected to the hollow channel 30 on the rotary card device 20 through a rotary sealing joint; the interior of the sampling bottle 6 is vacuumed.

[0046] The sampling bottles are numbered at 6, and can be numbered according to the description. Figure 4 The samplers are numbered in the manner shown (please refer to the numbers ①-⑥ in the figure). The number of samplers in this embodiment is limited only for the convenience of description. The samplers can also be used in other even numbers such as 8 groups, 10 groups, 12 groups, etc.; when it is necessary to sample the light non-aqueous phase liquid in the upper part of the aquifer, after the sampling mechanism reaches the corresponding sampling depth, the synchronous pusher pushes each sampler to feed away from the center of the monitoring well pipe until the sampling tube 7 is inserted into the corresponding sampling hole 3, the first self-closing valve 4 and the second self-closing valve 8 are both opened, the electromagnetic three-way valves 29 at numbers ① and ④ are opened, and the other electromagnetic three-way valves 29 are in the closed state, so that the water sample from the upper part of the corresponding aquifer flows into the sampling bottles 6 at numbers ① and ④; then the sampling mechanism is reset and moved to the sampling hole in the middle of the aquifer. 3, the sampling bottles 6 at number ② and number ⑤ are used to sample the water in the middle of the aquifer, and the water samples in the lower part of the aquifer are sampled through the sampling bottles 6 at number ③ and number ⑥ according to the above principle. In this way, at least two groups of parallel sampling of water samples from the upper, middle and lower layers of the aquifer can be carried out, and the sampling mechanism can complete the sampling of water samples at different depths in the aquifer with one dive, which greatly improves the sampling efficiency. At the same time, the symmetrical sampling method along the two sides of the monitoring well pipe can relatively reduce the disturbance of the sampled water layer, improve the accuracy of water sampling, and provide guarantee for the accuracy of subsequent water sample pollution detection; and the sampling bottle 6 is vacuumed after installation, which can improve the smoothness of the water sample flowing into the sampling bottle 6, effectively ensure the sampling amount of water sample in the sampling bottle 6, and avoid too little water sample.

[0047] When sampling water from the middle or lower layers of the aquifer, part of the upper layer will enter the sampling holes 3 at number ② and number ⑤, while part of the water samples from the upper and middle layers will enter the sampling holes 3 and sampling tubes 7 at number ③ and number ⑥. The mixing of this part of the water sample will cause deviations in the sampling accuracy. Before sampling, adjust the electromagnetic three-way valves 29 at number ② and number ⑤ and number ③ and number ⑥ to the bottom of the electromagnetic three-way valve 29 and one end connected to the sampling bottle 6 to be closed, and the horizontal end of the electromagnetic three-way valve 29 is connected to the sampling tube 7 and the first connecting pipe 26 and the corresponding electromagnetic three-way valve. The connection at one end of the top of the valve 29 is opened, and the water pump 28 is started, so that the water sample in the middle of the aquifer flushes the residual water sample in the sampling holes 3 and sampling tube 7 at positions ② and ⑤, and the water sample at the bottom of the aquifer flushes the residual water sample in the sampling holes 3 and sampling tube 7 at positions ③ and ⑥, and the extracted water is discharged through the first connecting pipe 26, the hollow channel 30 and the second connecting pipe 27, thereby reducing the mixing between water samples at different depths, thereby ensuring the sampling accuracy of the water samples in the middle and lower layers of the aquifer, and ensuring that the subsequent water sample detection is more objective and accurate.

[0048] For details, please refer to Figure 1 and Figure 5 , also includes a support frame 31 installed on the frame 18 and a guide wheel 32 rotatably installed on the top of the support frame 31, a hollow roller 33 is rotatably installed on the frame 18, the second connecting pipe 27 passes around the guide wheel 32 and is wrapped around the hollow roller 33, the output end of the second connecting pipe 27 extends into the hollow roller 33, the input end of the water pump 28 extends into the hollow roller 33, and a servo motor (not shown in the figure) is installed on the frame 18 to provide power for the rotation of the hollow roller 33; further, the input end of the water pump 28 is connected to the inside of the hollow roller 33 through a rotary sealing joint.

[0049] During the movement of the sampling mechanism up and down along the monitoring well pipe, the servo motor drives the hollow roller 33 to rotate, so that the second connecting tube 27 is wound around the hollow roller 33 or gradually detached from the hollow roller 33, to prevent the second connecting tube 27 from scattering everywhere; by starting the water pump 28, equal amounts of water samples corresponding to the upper, middle and lower parts of the aquifer are extracted into the hollow roller 33, and the hollow roller 33 achieves sufficient mixing of multiple layers of water samples during the rotation process, and the mixed water sample is received at the output end of the water pump 28. The detection data of the mixed water sample is compared and analyzed with the detection data of the water samples of the upper, middle and lower layers of the aquifer to obtain more accurate water sample pollution data.

[0050] For details, please refer to Figure 4-Figure 8The inner wall of the sampling pipe section 1 is provided with a plurality of equidistant and uniformly distributed annular cavities from top to bottom, and the sampling pipe section 1 is provided with a plurality of infiltration holes 34 connected to the annular cavity. The ring frame 2 is rotatably installed in the annular cavity, and the plurality of sampling holes 3 on the ring frame 2 are arranged corresponding to the plurality of infiltration holes 34. A infiltration net 35 is installed in the infiltration hole 34, and a plurality of circumferentially uniformly distributed sealing parts 36 are provided at the outer arm of the ring frame 2. An arc-shaped infiltration buffer cavity 37 is formed between the sealing parts 36, the outer wall of the ring frame 2 and the inner wall of the annular cavity; further, the ring frame 2 is inertially connected to the inner wall of the annular cavity to prevent the ring frame 2 from rotating by itself; the contact point between the ring frame 2 and the annular cavity is connected by a filler or the like for rotation sealing, and the filler can also prevent the ring frame 2 from rotating by itself; the infiltration net 35 adopts a dense mesh steel mesh, which has a certain structural strength and can filter mud and sand, etc., and the water sample can pass smoothly through the infiltration net 35.

[0051] When the monitoring well pipe is lowered, the sealing portion 36 on the ring frame 2 seals the seepage hole 34 to reduce the entry of sediment and water samples into the sampling hole 3, while improving the anti-extrusion strength of the seepage net 35 to avoid damage to the seepage net 35 due to soil squeezing, and effectively prevent the entry of soil, sediment, etc., which may cause the first self-closing valve 4 and the second self-closing valve 8 to be loosely closed; when sampling water samples at the corresponding depth of the aquifer, the synchronous pusher pushes each sampling tube 7 into the corresponding sampling hole 3, and the rotary driver 21 drives the rotary card 20 to rotate. After the transmission of the traction rod, polygonal frame 38, guide frame 5 and sampling tube 7, the ring The frame 2 rotates, and the sealing part 36 disengages from the sealing of the infiltration hole 34, and the water sample of the corresponding water layer flows into the arc-shaped infiltration buffer chamber 37 through the infiltration hole 34. The infiltration net 35 can filter the mud and sand, etc., so that the water sample enters the arc-shaped infiltration buffer chamber 37, so that the water sample can be sampled through the sampling tube 7 later; the arc-shaped infiltration buffer chamber 37 can also provide sufficient space for the opening of the first self-closing valve 4, thereby improving the opening smoothness and opening degree of the first self-closing valve 4 and the second self-closing valve 8. Under the same conditions, it effectively improves the flow rate of the water sample from the first self-closing valve 4 and the second self-closing valve 8, and further ensures the sampling amount of the water sample.

[0052] For details, please refer to Figure 1 as well as Figure 7-Figure 8 The monitoring well pipe includes multiple pipe sections 43 that are detachably connected at the head and tail, and a detection probe 44 is installed at the valve plug 16 on the first self-closing valve 4; further, the detection probe 44 is preferably a resistance detection probe, and chemical parameter sensors with different functions can also be installed, such as pH sensors, ion selective electrodes, heavy metal sensors, etc.; the detection end of the detection probe 44 is exposed from the valve plug 16.

[0053] According to the sampling requirements of aquifers at different depths, a corresponding number of pipe sections 43 can be selected so that the sampling pipe section 1 enters the corresponding aquifer; the detection probe 44 can detect the resistivity of different strata. The resistivity of the aquifer is lower than that of other soil or rock layers. Current is input into the underground through the detection probe 44 to measure the potential difference change and draw a resistivity profile, thereby determining the upper depth H1 and lower depth H2 of the aquifer. The bottom depth of the monitoring well pipe is at least H2+1m, and the height of the sampling pipe section 7 h≥H 2-H1, the water sample taken from the sampling hole 3 at the corresponding height H1 is the water sample of the upper part of the aquifer, the water sample taken from the sampling hole 3 at the corresponding height H2 is the water sample of the lower part of the aquifer, and the water sample taken from the sampling hole 3 at the corresponding height H1+H2-H1 / 2 is the water sample of the middle part of the aquifer. In this way, the upper, middle and lower water samples of the aquifer can be sampled accurately at a fixed depth. It should be noted that in order to reduce the sampling error of water samples from different water layers in the aquifer, the distance between each adjacent two self-closing plugging parts should be less than 1 cm.

[0054] The use process of the fixed-depth sampling device for NAPLs contaminated groundwater provided by the present invention is as follows: according to the underground depth and height of the underground aquifer surveyed in the early stage, the monitoring well pipe is driven into the ground by an external drill, and the sampling pipe section 1 is located in the aquifer. The walking mechanism is driven by the lifting tractor to move down along the inner wall of the monitoring well pipe to the self-closing plugging piece corresponding to the upper, middle or lower part of the required sampling water layer, the driving motor 10 drives the rotating disk 11 to rotate, the rotating disk 11 drives the driving block 12 to move, the driving block 12 pushes the valve member and the sampling tube 7 to move outward along the corresponding guide hole 9 until the sampling tube 7 extends into the sampling hole 3, the first self-closing valve 4 and the second self-closing valve 8 are opened, the rotary driver 21 drives the rotary card 20 to rotate, and after the traction rod, polygonal frame 38, guide frame 5 and sampling tube 7 are driven, the ring frame 2 rotates to Figure 4 In the state shown, the sampling hole 3 is connected to the corresponding arc-shaped infiltration buffer chamber 37, and the water of the corresponding water layer enters the arc-shaped infiltration buffer chamber 37 through the infiltration hole 34, and then flows into the sampling bottle 6 through the sampling hole 3, the sampling tube 7 and the valve body 14; after the sampling is completed, the ring frame 2 is reset, the blocking part 36 blocks the infiltration hole 34, and the first self-closing valve 4 and the second self-closing valve 8 close automatically after breaking contact, and the walking mechanism is lifted out of the monitoring well pipe by the lifting tractor, and the water sample obtained in the sampling bottle 6 is sent to the laboratory for testing.

[0055] In the present invention, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication between them; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

Claims

1. A NAPLs contaminated groundwater fixed depth sampling device, characterized in that: The invention comprises a monitoring well pipe, a sampling pipe section (1) arranged at the monitoring well pipe, and a sampling mechanism for sampling water samples at a fixed depth, wherein the sampling pipe section (1) is located in the aquifer to be sampled, and a plurality of self-closing plugging members arranged equidistantly from top to bottom are provided in the sampling pipe section (1); The self-closing plugging member comprises a ring frame (2), a plurality of sampling holes (3) equidistantly distributed around the ring frame (2) in the circumferential direction, and a first self-closing valve (4) installed in the sampling hole (3); the sampling mechanism comprises a running mechanism slidably installed in the monitoring well pipe, a guide frame (5) installed at the bottom of the running mechanism and arranged corresponding to the sampling holes (3), a plurality of samplers, and a synchronous pusher; The sampler comprises a sampling bottle (6), a valve component mounted at the mouth of the sampling bottle (6), a sampling tube (7) mounted on the valve component, and a second self-closing valve (8) mounted in the sampling tube (7); a guide hole (9) arranged corresponding to the sampling hole (3) is provided on the guide frame (5), and the sampling tube (7) is slidably mounted in the guide hole (9); The synchronous pusher comprises a driving motor (10) fixedly mounted on a walking mechanism, a rotating disk (11) fixedly mounted on an output end of the driving motor (10), and a plurality of driving blocks (12) circumferentially arranged on an outer wall of the rotating disk (11), wherein the driving blocks (12) are used to push a sampling tube (7) on a corresponding sampler to feed along a guide hole (9) toward a side away from the center of the rotating disk (11), and a first spring (13) is sleeved on the valve member, and the valve member is elastically connected to the guide frame (5) via the first spring (13); The first self-closing valve (4) and the second self-closing valve (8) both comprise a valve body (14), a valve stem (15), a valve plug (16) fixedly connected to the valve stem (15), and a second spring (17) sleeved on the valve stem (15); the valve stem (15) is slidably mounted in the valve body (14); the valve stem (15) is elastically connected to the valve body (14) via the second spring (17); when the second spring (17) is in an extended state, the valve plug (16) blocks the interior of the valve body (14); and the first self-closing valve (4) and the second self-closing valve (8) are arranged in a mirror image.

2. The NAPLs contaminated groundwater fixed depth sampling device according to claim 1, characterized in that: The invention also includes a lifting tractor for driving the walking mechanism to move up and down, the lifting tractor includes a frame (18), a lifting seat (19) slidably mounted on the frame (18), a rotary card (20) rotatably mounted on the lifting seat (19), a rotary driver (21) providing power for the rotary card (20) to rotate, a traction rod and a clamp, one end of the traction rod is fixedly connected to the upper part of the walking mechanism, and the other end of the traction rod is detachably connected to the rotary card (20), the traction rod includes a plurality of connecting rods (22) detachably connected to each other at the head and tail, the clamp includes two symmetrically arranged clamping members, the clamp includes an arc-shaped clamping arm (23) slidably mounted on the frame (18) and a feeder (24) providing power for the sliding of the arc-shaped clamping arm (23), and a lifting driver (25) is installed on the frame (18) to provide power for the lifting seat (19) to slide up and down along the frame (18).

3. The NAPLs contaminated groundwater fixed depth sampling device according to claim 2, characterized in that: It also includes a plurality of first connecting pipes (26), second connecting pipes (27) and a water pump (28), wherein the valve member is an electromagnetic three-way valve (29), the horizontal end of the electromagnetic three-way valve (29) is connected to the sampling tube (7), the bottom end of the electromagnetic three-way valve (29) is connected to the interior of the sampling bottle (6), one end of the first connecting pipe (26) is connected to the top end of the corresponding electromagnetic three-way valve (29), the middle of the connecting rod (22) and the rotary card device (20) are both provided with a hollow channel (30), the other end of the first connecting pipe (26) extends into the hollow channel (30) of a group of connecting rods (22) near the walking mechanism, one end of the second connecting pipe (27) is rotatably sealed with the hollow channel (30) on the rotary card device (20), and the other end of the second connecting pipe (27) is connected to the input end of the water pump (28).

4. The NAPLs contaminated groundwater fixed depth sampling device according to claim 3, characterized in that: The invention also includes a support frame (31) mounted on the frame (18) and a guide wheel (32) rotatably mounted on the top of the support frame (31); a hollow roller (33) is rotatably mounted on the frame (18); the second connecting pipe (27) passes around the guide wheel (32) and is wound around the hollow roller (33); the output end of the second connecting pipe (27) extends into the hollow roller (33); the input end of the water pump (28) extends into the hollow roller (33); and a servo motor is mounted on the frame (18) to provide power for the rotation of the hollow roller (33).

5. The NAPLs contaminated groundwater fixed depth sampling device according to claim 1, characterized in that: The inner wall of the sampling pipe section (1) is provided with a plurality of equidistant and evenly distributed annular cavities from top to bottom, the sampling pipe section (1) is provided with a plurality of infiltration holes (34) communicating with the annular cavities, the ring frame (2) is rotatably mounted in the annular cavity, the plurality of sampling holes (3) on the ring frame (2) are arranged corresponding to the plurality of infiltration holes (34), a infiltration net (35) is mounted in the infiltration holes (34), the outer arm of the ring frame (2) is provided with a plurality of circumferentially evenly distributed blocking portions (36), and an arc-shaped infiltration buffer cavity (37) is formed between the blocking portions (36), the outer wall of the ring frame (2) and the inner wall of the annular cavity.

6. The NAPLs contaminated groundwater fixed depth sampling device according to claim 1, characterized in that: The walking mechanism comprises a polygonal frame (38) and elastic centering supports equidistantly distributed along the outer wall of the polygonal frame (38) in the circumferential direction. The elastic centering supports comprise two symmetrically arranged support legs (39) hinged to the polygonal frame (38), a roller (40) rotatably mounted on the support legs (39) and a connecting spring (41). The two support legs (39) are elastically connected via the connecting spring (41).

7. The NAPLs contaminated groundwater fixed depth sampling device according to claim 1, characterized in that: A ball (42) is rotatably mounted on the valve member, and the drive block (12) is movably connected to the valve member via the ball (42).

8. The NAPLs contaminated groundwater fixed depth sampling device according to claim 1, characterized in that: The monitoring well pipe comprises a plurality of pipe sections (43) detachably connected at the head and tail ends, and a detection probe (44) is installed at the valve plug (16) on the first self-closing valve (4).

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