NAPLs polluted underground water fixed-depth sampling device

Abstract

The invention relates to the technical field of underground water sampling detection, in particular to a depth-keeping sampling device for NAPLs polluted underground water. The device can perform accurate stratified sampling on an upper water sample and a lower water sample of a depthkeeping aquifer, effectively reduces disturbance of the aquifer, improves the sampling precision of the water samples, and reduces the measurement error of the volume of polluted groundwater; comprising a monitoring well pipe, a sampling pipe section arranged at the monitoring well pipe and a sampling mechanism used for fixed-depth water sample sampling, and the self-closing type plugging piece comprises an annular frame, a plurality of sampling holes evenly distributed around the annular frame at equal intervals in the circumferential direction and first self-closing valves installed in the sampling holes; the sampling mechanism comprises a walking mechanism which can be installed in the monitoring well pipe in an up-down sliding mode, a guide frame which is installed at the bottom of the walking mechanism and corresponds to the sampling holes, a plurality of sampling devices and a synchronous pushing device. And the sampler comprises a sampling bottle, a valve piece mounted at a bottle opening of the sampling bottle, a sampling tube mounted on the valve piece and a second self-closing valve mounted in the sampling tube.

Description

Technical Field

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

[0002] Groundwater pollution is concealed. To explore the pollution situation of the groundwater layer, it is necessary to sample and detect the water samples of the groundwater layer. Nonaqueous Phase Liquids (NAPLs) are common pollutants in the groundwater of organic polluted sites. When NAPLs enter the groundwater aquifer, LNAPLs (light non-aqueous phase liquids) pollutants with a density smaller than that of water, such as petroleum products (gasoline, diesel, kerosene, etc.) and organic solvents (benzene, toluene, xylene, ethylbenzene, etc.), are prone to "float" on the groundwater surface and accumulate near the upper groundwater level in the aquifer; while relatively heavy DNAPLs (heavy non-aqueous phase liquids) pollutants, such as chlorinated solvents (trichloroethylene (TCE), perchloroethylene (PCE), polychlorinated biphenyls (PCB), etc.), coal tar, and petroleum derivatives, tend to migrate vertically downward and accumulate at the bottom of the aquifer, forming several aggregation areas of different sizes in the groundwater.

[0003] The accuracy of the investigation of the NAPLs pollution concentration and spatial distribution is directly related to the effect evaluation and decision-making support of the remediation of the polluted site. At present, groundwater sampling mainly uses bailer sampling or pumping water with a pump in a monitoring well for sampling. The groundwater samples collected by the above sampling methods and samplers are mostly surface water samples or mixed water samples of the upper and lower layers, which may not be able to represent the true concentration of NAPLs in the groundwater, may cause the NAPLs pollutants to be ignored, or overestimate the severity of the NAPLs pollution. In addition, the sampling depth of groundwater NAPLs directly affects the calculation of the NAPLs pollution volume. Therefore, for LNAPLs and DNAPLs, depth-specific stratified sampling should be carried out to ensure that the pollutants at different depths are accurately collected and objectively reflect the true pollution situation of NAPLs.

[0004] For another example, Chinese invention patent CN118624295B discloses a device for sampling groundwater at different depths for groundwater investigation, including an annular frame, a mounting seat, a collection cylinder, a limiting component, an adjustment component, and a pulling frame. It can complete sampling at multiple depth levels in sequence, with convenient operation and improved on-site sampling efficiency.

[0005] However, when the inventor specifically implemented this device, it was found that there were the following defects: LNAPLs pollutants float on the upper part of the underground aquifer, while DNAPLs pollutants settle at the lower part of the underground aquifer. When sampling with the above sampling device, it is easy to cause disturbance to the aquifer, and the LNAPLs and DNAPLs pollutants are mixed with water, resulting in distortion of the water sample data and making it difficult to reflect the true pollution situation of the groundwater. Summary of the Invention

[0006] (1) Technical Problem to be Solved In view of the deficiencies of the prior art, the present invention provides a NAPLs-contaminated groundwater depth-fixed sampling device that can accurately stratify and sample the upper water sample and the lower water sample of a depth-fixed aquifer, effectively reduce the disturbance of the aquifer, improve the sampling accuracy of the water sample, and reduce the measurement error of the volume of contaminated groundwater.

[0007] (2) Technical Solution To achieve the above object, the present invention provides the following technical solution: A device for sampling groundwater with a fixed depth contaminated by NAPLs, comprising a monitoring well pipe, a sampling pipe section arranged at the monitoring well pipe, and a sampling mechanism for sampling water samples at a fixed depth. The sampling pipe section is located in the aquifer to be sampled. A plurality of self-closing blocking members are arranged at equal intervals from top to bottom in the sampling pipe section. The self-closing blocking member includes a ring frame, a plurality of sampling holes evenly distributed circumferentially around the ring frame, and a first self-closing valve installed in the sampling hole. The sampling mechanism includes a walking mechanism slidably installed up and down in the monitoring well pipe, a guide frame installed at the bottom of the walking mechanism and arranged corresponding to the sampling holes, a plurality of samplers, and a synchronous pusher. The sampler includes a sampling bottle, a valve member installed at the bottle mouth of the sampling bottle, a sampling pipe installed on the valve member, and a second self-closing valve installed in the sampling pipe. The guide frame is provided with guide holes arranged corresponding to the sampling holes. The sampling pipe is slidably installed in the guide holes. The synchronous pusher includes 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 pipe on the corresponding sampler to feed away from the center of the rotating disk along the guide hole. A first spring is sleeved on the valve member. The valve member is elastically connected to the guide frame through the first spring. Further, the bottom of the monitoring well pipe is blocked, 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 for the upper, middle, and lower layers of water samples in the entire aquifer. The sampling hole is a cylindrical hole, and the central axis of the sampling hole coincides with the corresponding diameter line of the ring frame. The sampling pipe is internally connected to the sampling bottle through the valve member. 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 be solenoid valves or other electrically controlled valves with a self-opening effect. The walking mechanism can be equipped with its own walker to move the walking mechanism up and down along the inner wall of the monitoring well pipe, or the walking mechanism can be driven by a lifting tractor to move up and down along the inner wall of the monitoring well pipe. The driving block is in movable contact with the valve member on the corresponding sampler. One end of the driving block is inclined towards the center of the rotating disk, and the other end of the driving block is inclined away from the center of the rotating disk. The central axis of the sampling pipe forms an acute angle of 60° - 80° with 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 pipe, the inner wall of the guide hole, and the inner wall of the sampling hole are sealed by rubber or other fillers.

[0008] Preferably, both the first self-closing valve and the second self-closing valve include a valve body, a valve rod, a valve plug fixedly connected to the valve rod, and a second spring sleeved on the valve rod. The valve rod is slidably installed in the valve body. The valve rod is elastically connected to the valve body through the second spring. When the second spring is in the 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.

[0009] Preferably, it also includes a lifting traction device for driving the walking mechanism to move up and down, the lifting traction device includes a frame body, a lifting seat slidably mounted on the frame body, a rotary clamping device rotatably mounted on the lifting seat, a rotating driver for providing power for the rotary clamping device to rotate, a traction rod and a clamping device, 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 clamping device, the traction rod includes a plurality of connecting rods detachably connected to each other end to end, the clamping device includes two symmetrically arranged clamping members, the clamping member includes an arc-shaped clamping arm slidably mounted on the frame body and a feeder providing power for the sliding of the arc-shaped clamping arm, and a lifting driver is installed on the frame body to provide power for the lifting seat to slide up and down along the frame body; Furthermore, the connecting rods are threadedly connected, a group of connecting rods on the upper part are threadedly connected to the rotary card device, the rotary driver adopts a speed-regulating motor that can rotate in forward and reverse directions, and the rotary driver is connected to the rotary card device 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, and connecting rods of different sizes can be used in combination to effectively control the descent depth of the sampling mechanism.

[0010] Preferably, it also includes a plurality of first connecting tubes, second connecting tubes and a water pump, 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 tube is connected to the top end of the corresponding electromagnetic three-way valve, the connecting rod and the middle of the rotary card device are both provided with a hollow channel, the other end of the first connecting tube extends into the hollow channel of a group of connecting rods near the walking mechanism, one end of the second connecting tube is rotatably sealed and connected to the hollow channel on the rotary card device, and the other end of the second connecting tube is connected to the input end of the water pump; further, the first connecting tube and the second connecting tube are both flexible and plastic tubes lined with steel wire to avoid excessive deformation under the negative pressure of the water pump to affect the normal passage of water flow, and to avoid the first connecting tube from interfering with the movement of the valve component, and the second connecting tube is rotatably sealed and connected to the hollow channel on the rotary card device through a rotating sealing joint; the interior of the sampling bottle is vacuumed.

[0011] Preferably, it further includes a support frame installed on the frame body and a guide wheel rotatably installed at the top of the support frame. A hollow roller is rotatably installed on the frame body. The second communication pipe bypasses the guide wheel and then winds around the hollow roller. The output end of the second communication pipe extends into the hollow roller. The input end of the water pump extends into the hollow roller. A servo motor for providing power for the rotation of the hollow roller is installed on the frame body. Further, the input end of the water pump is communicated with the inside of the hollow roller through a rotary seal joint.

[0012] Preferably, a plurality of equally spaced and circumferentially distributed annular cavities are provided on the inner wall of the sampling pipe section from top to bottom. A plurality of percolation holes communicated with the annular cavities are provided on the sampling pipe section. The annular frame is rotatably installed in the annular cavity. A plurality of sampling holes on the annular frame are arranged corresponding to the plurality of percolation holes. A percolation filter screen is installed in the percolation holes. A plurality of circumferentially distributed blocking parts are provided on the outer arm of the annular frame. An arc-shaped percolation buffer cavity is formed between the blocking parts, the outer wall of the annular frame and the inner wall of the annular cavity. Further, the annular frame is inertially connected to the inner wall of the annular cavity to prevent the annular frame from rotating by itself. The contact part between the annular frame and the annular cavity is rotationally sealed through packing, and the packing can also prevent the annular frame from rotating by itself.

[0013] Preferably, the traveling mechanism includes a polygonal frame and elastic centering support members circumferentially and equally spaced along the outer wall of the polygonal frame. The elastic centering support members include two symmetrically arranged support legs hinged to the polygonal frame, rollers rotatably installed on the support legs, and connecting springs. The two support legs are elastically connected through the connecting springs. Further, the two ends of the connecting spring are respectively hinged to the two support legs.

[0014] Preferably, a ball is rotatably installed on the valve member. The driving block is movably connected to the valve member through the ball.

[0015] Preferably, the monitoring well pipe includes a plurality of pipe sections detachably connected end to end. A detection probe is installed at the valve plug of 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 a PH sensor, an ion selective electrode, a heavy metal sensor, etc. The detection end of the detection probe exposes from the valve plug.

[0016] (III) Beneficial effects Compared with the prior art, the present invention provides a device for depth-specific sampling of groundwater contaminated by NAPLs, having the following beneficial effects: The device for depth-specific sampling of groundwater contaminated by NAPLs, according to the aquifer burial depth and aquifer thickness surveyed in the early stage, drives the monitoring well pipe into the ground through an external drill, with the sampling pipe section located within the aquifer. The traveling mechanism moves down along the inner wall of the monitoring well pipe to the self-closing plug corresponding to the upper, middle, or lower part of the water layer to be sampled. The driving motor drives the rotating disk to rotate, the rotating disk drives the driving block to move, and the driving block pushes the valve member and the sampling pipe to move outward along the corresponding guiding holes until the sampling pipe extends into the sampling hole. The first self-closing valve and the second self-closing valve open, and the water in the sampling hole communicates with the water in the corresponding water layer. The water in the corresponding water layer flows into the sampling bottle through the sampling hole, the sampling pipe, and the valve body; it can accurately perform stratified sampling on the upper and lower water samples of the depth-specific aquifer, effectively reducing the disturbance of the aquifer and avoiding the re-migration of NAPLs during the sampling process; avoiding the mixing of LNAPLs in the upper part and DNAPLs pollutants in the lower part of the aquifer with the water in this aquifer, improving the sampling accuracy of the water sample and making the sample more representative; avoiding the dilution of pollutant concentration or the confusion of phase states, and being able to accurately locate the polluted layer; it can accurately capture the vertical distribution characteristics of pollutants by matching the physical and chemical properties of NAPLs with the hydrogeological conditions, and combining with stratified data collection, significantly improving the reliability of defining the NAPLs pollution range and calculating the remediation project quantity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a three-dimensional structural schematic diagram of the present invention; Figure 2 is a front-view plane structural schematic diagram of the present invention; Figure 3 is the Figure 2 cross-sectional structural schematic diagram at A-A of the present invention; Figure 4 is the Figure 3 cross-sectional structural schematic diagram at B-B of the present invention; Figure 5 is the Figure 3 partial enlarged structural schematic diagram at C of the present invention; Figure 6 is the Figure 3 partial enlarged structural schematic diagram at D of the present invention; Figure 7 is the Figure 4 partial enlarged structural schematic diagram at E of the present invention; Figure 8 is a three-dimensional structural schematic diagram of the self-closing plug of the present invention; Figure 9 is a three-dimensional structural schematic diagram of the sampling mechanism of the present invention; Figure 10 is the Figure 9Schematic diagram of the partially enlarged structure at position F in the [specific context]; Reference signs in the accompanying drawings: 1. Sampling pipe section; 2. Ring frame; 3. Sampling hole; 4. First self - closing valve; 5. Guide frame; 6. Sampling bottle; 7. Sampling pipe; 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 body; 19. Lifting seat; 20. Rotary chuck; 21. Rotary driver; 22. Connecting rod; 23. Arc - shaped clamping arm; 24. Feeder; 25. Lifting driver; 26. First connecting pipe; 27. Second connecting pipe; 28. Water pump; 29. Electromagnetic three - way valve; 30. Hollow channel; 31. Support frame; 32. Guide wheel; 33. Hollow roller; 34. Percolation hole; 35. Percolation filter screen; 36. Sealing part; 37. Arc - shaped percolation buffer cavity; 38. Polygonal frame; 39. Support leg; 40. Roller; 41. Connecting spring; 42. Ball; 43. Pipe joint; 44. Detection probe. Detailed implementation manners

[0018] In order to enable those skilled in the art to better understand the invention solution, the technical solutions in the embodiments of the invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the invention. Obviously, the described embodiments are only a part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments in the invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the invention.

[0019] As a groundwater sampling device for different depths used in groundwater investigation as described in the background technology, most of the polluted water samples in the groundwater layer are organic substances. 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 groundwater aquifer, while heavy non - aqueous phase liquid pollutants settle at the lower part of the groundwater aquifer. Light non - aqueous phase liquid pollutants and heavy non - aqueous phase liquid pollutants are important indicators for measuring groundwater pollution; during sampling, it is easy to cause disturbance to the aquifer, and light non - aqueous phase liquids and heavy non - aqueous phase liquid pollutants are mixed with water, resulting in distortion of the water sample data and making it difficult to reflect the true pollution situation of the groundwater.

[0020] To solve this technical problem, the present invention provides a NAPLs - polluted groundwater depth - fixed sampling device, which is applied to the layered sampling of groundwater aquifers.

[0021] It should be noted that, without conflict, the embodiments in the invention and the features and technical solutions in the embodiments can be combined with each other.

[0022] It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further definition and explanation thereof is not required in subsequent figures. Example 1

[0023] Please refer to Figures 1-4 and Figures 6-10, a device for depth-fixed sampling of groundwater contaminated by NAPLs, specifically including: a monitoring well pipe, a sampling pipe section 1 arranged at the monitoring well pipe, and a sampling mechanism for depth-fixed sampling of water samples. The sampling pipe section 1 is located in the aquifer to be sampled. Multiple self-closing sealing members are arranged at equal intervals from top to bottom in the sampling pipe section 1. The self-closing sealing member includes a ring frame 2, multiple sampling holes 3 evenly distributed circumferentially around the ring frame 2, and a first self-closing valve 4 installed in the sampling hole 3; the sampling mechanism includes a traveling mechanism slidably installed up and down in the monitoring well pipe, a guide frame 5 installed at the bottom of the traveling mechanism and arranged corresponding to the sampling holes 3, multiple samplers, and a synchronous pusher. The sampler includes a sampling bottle 6, a valve member installed at the bottle mouth of the sampling bottle 6, a sampling pipe 7 installed on the valve member, and a second self-closing valve 8 installed in the sampling pipe 7. The guide frame 5 is provided with guide holes 9 arranged corresponding to the sampling holes 3, and the sampling pipe 7 is slidably installed in the guide holes 9. The synchronous pusher includes a driving motor 10 fixedly installed on the traveling mechanism, a rotating disk 11 fixedly installed at the output end of the driving motor 10, and multiple driving blocks 12 arranged circumferentially on the outer wall of the rotating disk 11. The driving block 12 is used to push the sampling pipe 7 on the corresponding sampler to feed along the guide hole 9 away from the center of the rotating disk 11. A first spring 13 is sleeved on the valve member, and the valve member is elastically connected to the guide frame 5 through the first spring 13. Further, 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 for the upper, middle, and lower layers of water samples in the entire aquifer; the sampling hole 3 is a cylindrical hole, and the central axis of the sampling hole 3 coincides with the corresponding diameter line of the ring frame 2; the sampling pipe 7 is internally connected to the sampling bottle 6 through the valve member. The first self-closing valve 4 and the second self-closing valve 8 are normally closed valves, and the first self-closing valve 4 and the second self-closing valve 8 can be solenoid valves or other electronically controlled valves with self-starting effects; the traveling mechanism can be equipped with a self-propelled device to move the traveling mechanism up and down along the inner wall of the monitoring well pipe, or the traveling mechanism can be driven to move up and down along the inner wall of the monitoring well pipe by a lifting traction device; the driving block 12 is in movable contact with the valve member on the corresponding sampler. One end of the driving block 12 is inclined towards the center of the rotating disk 11, and the other end of the driving block 12 is inclined away from the center of the rotating disk 11. The central axis of the sampling pipe 7 forms an acute angle of 60° - 80° with the driving block 12; 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. After the driving block 12 is separated from the valve member, the first spring 13 can prompt the valve member and the sampling pipe 7 to reset themselves, so that the sampling pipe 7 moves out of the sampling hole 3 by itself; the outer wall of the sampling pipe 7, 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 the multiple sampling holes 3 are provided on the upper part of the monitoring well pipe. After the guide holes 9 on the sampling mechanism are aligned with the marks and then move down along the inner wall of the monitoring well pipe, the distance that the sampling mechanism moves down is the position of the sampling hole 3 at the sampling water layer of the corresponding depth, so as to ensure the smooth alignment of the sampling hole 3 and the guide hole 9.

[0024] Specifically, please refer to Figure 6 and Figure 9 , the traveling mechanism includes a polygonal frame 38 and elastic centering supports evenly distributed at equal intervals along the outer wall of the polygonal frame 38 in the circumferential direction. The elastic centering supports include two symmetrically arranged legs 39 hinged to the polygonal frame 38, rollers 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, both ends of the connecting spring 41 are respectively hinged to the two legs 39.

[0025] Specifically, please refer to Figure 4 ; a ball 42 is rotatably mounted on the valve member, and the driving block 12 is movably connected to the valve member through the ball 42.

[0026] Specifically, please refer to Figure 7 , both the first self-closing valve 4 and the second self-closing valve 8 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 mounted in the valve body 14, and the valve stem 15 is elastically connected to the valve body 14 through the second spring 17. When the second spring 17 is in the extended state, the valve plug 16 seals the inside 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.

[0027] In the NAPLs contaminated groundwater depth-fixed sampling device provided in this embodiment, under the action of the connecting spring 41, the two legs 39 tend to move closer to each other. Under the action of each elastic centering support, the vertical central axis of the polygonal frame 38 coincides with the central axis of the monitoring well pipe, and at the same time, the stability of the traveling mechanism moving up and down along the inner wall of the monitoring well pipe can be improved, and the polygonal frame 38 is prevented from shaking; while the ball 42 can realize the rolling contact between the driving block 12 and the valve member, effectively reducing the friction between the driving block 12 and the valve member, improving the transmission efficiency between the driving block 12 and the valve member, and reducing the output power of the driving motor 10.

[0028] After the sampling tube 7 extends 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 plugs 16 are disengaged from sealing the inside of the valve body 14, so that the sampling tube 7 is communicated with the sampling hole 3; thus, the mechanical opening of the first self-closing valve 4 and the second self-closing valve 8 can be realized. 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 inside of the monitoring well pipe, so as to avoid the mutual mixing and contact between water layers at different depths in the aquifer and ensure the sampling accuracy of the water sample.

[0029] 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 to achieve water sampling of aquifers at different depths.

[0030] The NAPLs contaminated groundwater fixed depth sampling device provided in Example 1 is further optimized. For details, please refer to Figures 1-3 as well as Figures 5-6 , and also includes a lifting traction device for driving the walking mechanism to move up and down. The lifting traction device includes a frame 18, a lifting seat 19 slidably installed on the frame 18, a rotary card 20 rotatably installed 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 head to tail. The clamp includes two symmetrically arranged clamping members, and the clamping member includes an arc-shaped clamping arm 23 slidably installed 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, a group of connecting rods 22 at the upper part are threadedly connected to the rotary card device 20, the rotating driver 21 adopts a speed regulating motor that can rotate in forward and reverse directions, and the rotating driver 21 is connected to the rotary card device 20 through transmission parts such as gears or chains; 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, and can also adopt 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 size, such as 5cm, 10cm, 20cm, 30cm, 50cm, etc., according to the sampling depth, the connecting rod 22 of appropriate specification length can be selected, and the connecting rods 22 of different sizes can be used in combination to effectively control the descent depth of the sampling mechanism.

[0031] 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 and the upper part of the group of connecting rods 22 at the upper part is clamped 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 required sampling water layer, the appropriate specifications and number 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.

[0032] For details, please refer to Figures 2-7 and Figures 9-10, also includes a plurality of first connecting pipes 26, second connecting pipes 27 and a water pump 28. The valve is an electromagnetic three-way valve 29. The horizontal end of the electromagnetic three-way valve 29 is connected to the sampling pipe 7, and the bottom end of the electromagnetic three-way valve 29 is internally connected to 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. Both the connecting rod 22 and the rotary clamp 20 are provided with a hollow channel 30 in the middle. The other end of the first connecting pipe 26 extends into the hollow channel 30 of a group of connecting rods 22 near the traveling mechanism. One end of the second connecting pipe 27 is rotatably and sealingly connected to the hollow channel 30 on the rotary clamp 20, and the other end of the second connecting pipe 27 is connected to the input end of the water pump 28; further, both the first connecting pipe 26 and the second connecting pipe 27 are flexible plastic pipes lined with steel wires to avoid excessive deformation under the negative pressure pumping of the water pump 28, which affects the normal passage of water flow, and to avoid interference of the first connecting pipe 26 with the movement of the valve. The second connecting pipe 27 is rotatably and sealingly connected to the hollow channel 30 on the rotary clamp 20 through a rotary sealing joint; the inside of the sampling bottle 6 is subjected to a vacuum treatment.

[0033] Number the sampling bottles 6. For convenience of description, the numbering can be carried out in the Figure 4 shown manner (please refer to the numbering at ①-⑥ in the figure). The number of samplers in this embodiment is only limited for convenience of description. The sampler can also be 8 groups, 10 groups, 12 groups or other even numbers; when sampling the light non-aqueous phase liquid above 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 pipe 7 is inserted into the corresponding sampling hole 3. Both the first self-closing valve 4 and the second self-closing valve 8 are opened, and the electromagnetic three-way valves 29 at No. ① and No. ④ are opened, and the rest of the electromagnetic three-way valves 29 are in the closed state, so that the water samples above the corresponding aquifer flow into the sampling bottles 6 at No. ① and No. ④; then the sampling mechanism resets and moves to the sampling hole 3 in the middle of the aquifer. The sampling bottles 6 at No. ② and No. ⑤ sample the middle water of the aquifer. According to the above principle, the sampling bottles 6 at No. ③ and No. ⑥ sample the water samples below the aquifer. In this way, at least two groups of parallel samples can be taken for the upper, middle and lower layers of water samples in the aquifer, and the sampling mechanism can complete the sampling of water samples at different depths in the aquifer by diving once, which greatly improves the sampling efficiency. At the same time, the method of symmetrically sampling along both sides of the monitoring well pipe can relatively reduce the disturbance to the sampled water layer and improve the accuracy of water sample sampling, providing guarantee for the accuracy of subsequent water sample pollution detection; and the sampling bottle 6 is subjected to a vacuum treatment after installation, which can improve the smoothness of the water sample flowing into the sampling bottle 6, effectively ensure the sampling volume of the water sample in the sampling bottle 6, and avoid too little sampling volume of the water sample.

[0034] When sampling the water samples in the middle or lower layer of the aquifer, a part of the upper layer will enter the sampling holes 3 at the positions numbered ② and ⑤, and a part of the water samples in the upper and middle layers will enter the sampling holes 3 and the sampling pipes 7 at the positions numbered ③ and ⑥. The mixing of this part of the water samples will cause deviation in the sampling accuracy. Before sampling, adjust the electromagnetic three-way valves 29 at the positions numbered ② and ⑤ and at the positions numbered ③ and ⑥ so that the end of the electromagnetic three-way valve 29 connected to the sampling bottle 6 at the bottom is closed, and the horizontal end of the electromagnetic three-way valve 29 is opened at the connection with the sampling pipe 7 and at the top end of the first connecting pipe 26 corresponding to the electromagnetic three-way valve 29. Start the water pump 28 so that the water samples in the middle of the aquifer flush the residual water samples in the sampling holes 3 and the sampling pipes 7 at the positions numbered ② and ⑤, and the water samples at the bottom of the aquifer flush the residual water samples in the sampling holes 3 and the sampling pipes 7 at the positions numbered ③ and ⑥. The pumped water is discharged through the first connecting pipe 26, the hollow channel 30 and the second connecting pipe 27, reducing the mutual mixing between water samples at different depths, thus ensuring the sampling accuracy of the water samples in the middle and lower layers of the aquifer and ensuring more objective and accurate subsequent water sample detection.

[0035] Specifically, please refer to Figure 1 and Figure 5 , and 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 is wound around the hollow roller 33 after bypassing the guide wheel 32. The output end of the second connecting pipe 27 extends into the hollow roller 33, and the input end of the water pump 28 extends into the hollow roller 33. A servo motor (not shown in the figure) for providing power for the rotation of the hollow roller 33 is installed on the frame 18; further, the input end of the water pump 28 is internally connected to the hollow roller 33 through a rotary seal joint.

[0036] During the process of the sampling mechanism moving up and down along the monitoring well pipe, the servo motor drives the hollow roller 33 to rotate, so that the second connecting pipe 27 is wound around the hollow roller 33 or gradually disengages from the hollow roller 33, preventing the second connecting pipe 27 from scattering everywhere; by starting the water pump 28, an equal amount of water samples from the upper, middle and lower parts of the corresponding aquifer are pumped into the hollow roller 33. The hollow roller 33 realizes the full mixing of water samples in multiple layers during rotation. Take the mixed water sample at the output end of the water pump 28, and compare and analyze the detection data of the mixed water sample with the detection data of the water samples in the upper, middle and lower layers of the aquifer to obtain more accurate water sample pollution data.

[0037] Specifically, please refer to Figures 4-8, a plurality of equally spaced and uniformly distributed annular cavities are provided on the inner wall of the sampling pipe section 1 from top to bottom. A plurality of percolation holes 34 communicating with the annular cavities are provided on the sampling pipe section 1. The annular frame 2 is rotatably installed in the annular cavity. A plurality of sampling holes 3 on the annular frame 2 are arranged corresponding to the plurality of percolation holes 34. A percolation screen 35 is installed in the percolation holes 34. A plurality of circumferentially uniformly distributed blocking parts 36 are provided on the outer arm of the annular frame 2. An arc-shaped percolation buffer cavity 37 is formed between the blocking parts 36, the outer wall of the annular frame 2 and the inner wall of the annular cavity; further, the annular frame 2 is inertially connected to the inner wall of the annular cavity to prevent the annular frame 2 from rotating by itself; the contact part between the annular frame 2 and the annular cavity is rotationally sealed by packing, and the packing can also prevent the annular frame 2 from rotating by itself; the percolation screen 35 is made of a dense-mesh steel net, and the dense-mesh steel net has a certain structural strength and can filter sediment and the like, and the water sample can smoothly pass through the percolation screen 35.

[0038] When lowering the monitoring well pipe, the blocking part 36 on the annular frame 2 blocks the percolation holes 34 to reduce the entry of sediment, water samples, etc. into the sampling holes 3, and at the same time improve the anti-extrusion strength at the percolation screen 35 to avoid damage to the percolation screen 35 due to soil extrusion, and effectively prevent the entry of soil, sediment, etc. from causing the first self-closing valve 4 and the second self-closing valve 8 to be not tightly closed; when sampling the water sample at the corresponding depth of the aquifer, the synchronous pusher pushes each sampling pipe 7 into the corresponding sampling hole 3, and the rotary driver 21 drives the rotary clamp 20 to rotate. After being transmitted through the traction rod, the polygonal frame 38, the guide frame 5 and the sampling pipe 7, the annular frame 2 rotates, and the blocking part 36 disengages from the blocking of the percolation holes 34. The water sample of the corresponding water layer flows into the arc-shaped percolation buffer cavity 37 through the percolation holes 34. The percolation screen 35 can filter sediment and the like, so that the water sample enters the arc-shaped percolation buffer cavity 37 for subsequent sampling of the water sample through the sampling pipe 7; the arc-shaped percolation buffer cavity 37 can also provide sufficient space for the opening of the first self-closing valve 4, improve the opening smoothness and opening degree of the first self-closing valve 4 and the second self-closing valve 8, and effectively improve the flow rate of the water sample from the first self-closing valve 4 and the second self-closing valve 8 under the same conditions, and further ensure the sampling volume of the water sample.

[0039] Specifically, please refer to Figure 1 and Figures 7-8 , the monitoring well pipe includes a plurality of pipe sections 43 that are detachably connected end to end. A detection probe 44 is installed at the valve plug 16 of the first self-closing valve 4; further, the detection probe 44 is preferably a resistance detection probe, and different functional chemical parameter sensors can also be installed, such as a PH sensor, an ion-selective electrode, a heavy metal sensor, etc.; the detection end of the detection probe 44 exposes from the valve plug 16.

[0040] According to the sampling requirements of aquifers at different depths, the 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 layers or rock layers. By inputting current into the ground through the detection probe 44 and measuring the change in potential difference, a resistivity profile is drawn to determine the upper depth H1 and lower depth H2 of the aquifer. The lower pipe depth of the monitoring well pipe is at least H2 + 1m, and the height h of the sampling pipe 7 section is h ≥ H2 - 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, accurate sampling of water samples at the upper, middle, and lower parts of the aquifer can be carried out at a fixed depth; it should be noted that in order to reduce the sampling error of water samples in different water layers of the aquifer, the distance between every two adjacent self-closing sealing parts should be less than 1 cm.

[0041] The use process of the NAPLs contaminated groundwater fixed-depth sampling device provided by the present invention is as follows: According to the underground depth of the underground aquifer and the height of the aquifer surveyed in the early stage, the monitoring well pipe is driven into the ground by an external drill. The sampling pipe section 1 is located in the aquifer. The lifting and traction device drives the walking mechanism to move down along the inner wall of the monitoring well pipe to the self-closing sealing part corresponding to the upper, middle, or lower part of the required sampling water layer. The drive motor 10 drives the rotating disk 11 to rotate, and the rotating disk 11 drives the drive block 12 to move. The drive block 12 pushes the valve part and the sampling pipe 7 to move outward along the corresponding guide hole 9 until the sampling pipe 7 extends into the sampling hole 3. The first self-closing valve 4 and the second self-closing valve 8 are opened. The rotary drive 21 drives the rotary clamp 20 to rotate. After being transmitted through the traction rod, the polygonal frame 38, the guide frame 5, and the sampling pipe 7, the ring frame 2 rotates to Figure 4 the state shown, the sampling hole 3 is communicated with the corresponding arc-shaped filtration buffer cavity 37, the water of the corresponding water layer enters the arc-shaped filtration buffer cavity 37 through the filtration hole 34, and then flows into the sampling bottle 6 through the sampling hole 3, the sampling pipe 7, and the valve body 14; after sampling, the ring frame 2 resets, the sealing part 36 seals the filtration hole 34, and the first self-closing valve 4 and the second self-closing valve 8 close automatically after being separated. The walking mechanism is lifted out of the monitoring well pipe by the lifting and traction device, and the water sample obtained in the sampling bottle 6 is sent to the laboratory for testing.

[0042] In the invention, unless otherwise clearly defined and limited, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or capable of communicating with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

Claims

1. A device for depth - specific sampling of groundwater contaminated by NAPLs, characterized in that, It includes a monitoring well pipe, a sampling pipe section (1) arranged at the monitoring well pipe, and a sampling mechanism for deep water sampling. The sampling pipe section (1) is located in the aquifer to be sampled, and a plurality of self-closing blocking members are arranged at equal intervals from top to bottom in the sampling pipe section (1). The self-closing blocking member includes a ring frame (2), a plurality of sampling holes (3) evenly distributed circumferentially around the ring frame (2), and a first self-closing valve (4) installed in the sampling hole (3); the sampling mechanism includes a walking mechanism slidably installed up and down in the monitoring well pipe, a guide frame (5) installed at the bottom of the walking mechanism and arranged corresponding to the sampling hole (3), a plurality of samplers, and a synchronous pusher. The sampler includes a sampling bottle (6), a valve member installed at the mouth of the sampling bottle (6), a sampling pipe (7) installed on the valve member, and a second self-closing valve (8) installed in the sampling pipe (7). A guide hole (9) corresponding to the sampling hole (3) is provided on the guide frame (5), and the sampling pipe (7) is slidably installed in the guide hole (9). The synchronous pusher includes a driving motor (10) fixedly installed on the walking mechanism, a rotating disk (11) fixedly installed at the output end of the driving motor (10), and a plurality of driving blocks (12) circumferentially arranged on the outer wall of the rotating disk (11). The driving block (12) is used to push the sampling pipe (7) on the corresponding sampler to feed along the guide hole (9) away from the center of the rotating disk (11). A first spring (13) is sleeved on the valve member, and the valve member is elastically connected to the guide frame (5) through the first spring (13).

2. The NAPLs contaminated groundwater depth-fixed sampling device according to claim 1, wherein Both the first self-closing valve (4) and the second self-closing valve (8) include a valve body (14), a valve rod (15), a valve plug (16) fixedly connected to the valve rod (15), and a second spring (17) sleeved on the valve rod (15). The valve rod (15) is slidably installed in the valve body (14), and the valve rod (15) is elastically connected to the valve body (14) through the second spring (17). When the second spring (17) is in the 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.

3. The NAPLs contaminated groundwater depth-fixed sampling device according to claim 2, wherein, It also includes a lifting tractor for driving the walking mechanism to move up and down. The lifting tractor includes a frame body (18), a lifting seat (19) slidably installed up and down on the frame body (18), a rotary chuck (20) rotatably installed on the lifting seat (19), a rotary driver (21) for providing power for the rotation of the rotary chuck (20), a traction rod, and a clamping device. 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 chuck (20). The traction rod includes a plurality of connecting rods (22) detachably connected end to end. The clamping device includes two symmetrically arranged clamping members. The clamping member includes an arc-shaped clamping arm (23) slidably installed on the frame body (18) and a feeder (24) for providing power for the sliding of the arc-shaped clamping arm (23). A lifting driver (25) for providing power for the lifting seat (19) to slide up and down along the frame body (18) is installed on the frame body (18).

4. The NAPLs contaminated groundwater depth-fixed sampling device according to claim 3, wherein, It further 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 communicated with the sampling pipe (7). One bottom end of the electromagnetic three-way valve (29) is communicated with the inside of the sampling bottle (6). One end of the first connecting pipe (26) is communicated with the top end of the corresponding electromagnetic three-way valve (29). A hollow channel (30) is provided in the middle of both the connecting rod (22) and the rotary chuck (20). The other end of the first connecting pipe (26) extends into the hollow channel (30) of a group of connecting rods (22) near the traveling mechanism. One end of the second connecting pipe (27) is rotatably and sealingly connected to the hollow channel (30) on the rotary chuck (20). The other end of the second connecting pipe (27) is communicated with the input end of the water pump (28).

5. The NAPLs contaminated groundwater depth-fixed sampling device according to claim 4, characterized in that, It further includes a support frame (31) installed on the frame body (18) and a guide wheel (32) rotatably installed at the top of the support frame (31). A hollow roller (33) is rotatably installed on the frame body (18). The second connecting pipe (27) winds around the hollow roller (33) after bypassing the guide wheel (32). 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). A servo motor for providing power for the rotation of the hollow roller (33) is installed on the frame body (18).

6. The NAPLs contaminated groundwater depth-fixed sampling device according to claim 1, characterized in that A plurality of equally spaced and circumferentially distributed annular cavities are provided on the inner wall of the sampling pipe section (1) from top to bottom. A plurality of percolation holes (34) communicated with the annular cavities are provided on the sampling pipe section (1). The annular frame (2) is rotatably installed in the annular cavity. A plurality of sampling holes (3) on the annular frame (2) are arranged corresponding to the plurality of percolation holes (34). A percolation filter screen (35) is installed in the percolation holes (34). A plurality of circumferentially distributed blocking parts (36) are provided on the outer arm of the annular frame (2). An arc-shaped percolation buffer cavity (37) is formed between the blocking parts (36), the outer wall of the annular frame (2) and the inner wall of the annular cavity.

7. The NAPLs contaminated groundwater depth-fixed sampling device according to claim 1, characterized in that, The traveling mechanism includes a polygonal frame (38) and elastic centering support members circumferentially and equally spaced on the outer wall of the polygonal frame (38). The elastic centering support members include two symmetrically arranged support legs (39) hinged to the polygonal frame (38), rollers (40) rotatably installed on the support legs (39) and connecting springs (41). The two support legs (39) are elastically connected by the connecting springs (41).

8. The NAPLs contaminated groundwater depth-fixed sampling device according to claim 1, wherein A ball (42) is rotatably installed on the valve member. The driving block (12) is movably connected to the valve member through the ball (42).

9. The NAPLs contaminated groundwater depth-fixed sampling device according to claim 1, characterized in that, The monitoring well pipe includes a plurality of pipe sections (43) detachably connected end to end. A detection probe (44) is installed at the valve plug (16) of the first self-closing valve (4).

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