A clogging-resistant system for synchronously collecting microplastics of multiple sizes in water

Abstract

The present invention discloses a system for synchronously collecting microplastics with multiple particle sizes in water bodies that prevents clogging, comprising: a water inlet pipe; a multi-stage screen assembly device connected to the water inlet pipe, the multi-stage screen assembly device being provided with at least two levels of screens with different apertures; a receiving bucket connected to the water outlet of the multi-stage screen assembly device; and a rotating water inlet assembly provided at the connection between the water inlet pipe and the multi-stage screen assembly device. In the present invention, a large sample of water comes in from the water inlet pipe and enters the multi-stage screen assembly device through a rotating water inlet assembly. The rotating water inlet assembly ensures that the incoming water evenly washes the top screen surface, preventing small-particle-size microplastics from being retained on the top large-aperture screen surface, thereby improving the accuracy of the later detection results. Microplastic particles of different particle sizes are retained on the screen layer of the corresponding aperture. The present invention realizes synchronous particle size classification and collection of microplastics in large sample water bodies, thereby improving the accuracy of water body microplastic pollution detection.

Description

Technical Field

[0001] The invention relates to a water body microplastic collection system, belongs to the field of water environment detection, and specifically relates to an anti-clogging water body multi-particle size microplastic synchronous collection system. Background Art

[0002] Microplastics, as a new type of pollutant in water bodies, are usually described as plastic polymer particles with a particle size of less than 5 mm. Due to their prevalence in water bodies, their own ecotoxicity, and their stable chemical properties that can remain in water bodies for hundreds of years, it is urgent to conduct comprehensive research on microplastic water pollution and ecological risks. At present, there have been many studies on the occurrence and migration of microplastics in the ocean, freshwater environment and sewage treatment plants, and there have also been a small number of studies on the occurrence of microplastics in water plants, tap water and bottled water. However, the sampling method for microplastics in water bodies has not yet been standardized, and there is still a lack of accuracy in the collection equipment and methods.

[0003] At present, there are generally three sampling methods for microplastic samples in water bodies: one is collection in small sample containers. Due to the uneven spatial distribution of microplastics in water bodies, too low a water sample capacity will increase the error, that is, large sample water body detection is more conducive to the accuracy of detection, especially when the detection object is a water body with a low microplastic content; the second is trawl collection. The aperture of the trawl is set to a single level, and there is a large error when collecting small-sized microplastics. The large-aperture mesh is easy to miss small-sized particles and the small-aperture mesh is easy to be blocked by other impurities in the water body, which is not conducive to the scientific assessment of the degree of microplastic pollution in the water body; the third is filter enrichment. The water sample is pumped or directly poured into a container into a closed one-stage or multi-stage filter screen with different apertures. This can realize the detection of large sample water bodies and classify the collected microplastics by particle size, but the enrichment work is often stopped due to blockage, and the closed shell of the filter makes the collection and cleaning procedures complicated.

[0004] In view of the above situation, the present invention designs a synchronous collection system for microplastics of multiple particle sizes that is suitable for large sample water body detection and easy to solve blockage. Summary of the invention

[0005] The purpose of the present invention is to provide a clogging-resistant system for synchronously collecting microplastics of multiple particle sizes in water bodies, so as to achieve synchronous particle size classification and collection of microplastics in large sample water bodies, thereby improving the accuracy of water microplastic pollution detection, which is achieved through the following scheme.

[0006] A system for synchronously collecting microplastics of multiple particle sizes in water bodies that prevents clogging, comprising:

[0007] Water inlet pipe:

[0008] A multi-stage screen assembly device connected to the water inlet pipe, wherein the multi-stage screen assembly device is provided with at least two stages of screens with different apertures;

[0009] A receiving bucket connected to the water outlet of the multi-stage screen assembly;

[0010] And, a rotating water inlet assembly is arranged at the connection between the water inlet pipe and the multi-stage screen assembly device.

[0011] In the present invention, a large sample of water comes in from a water inlet pipe and enters a multi-stage screen assembly device through a rotating water inlet assembly. The rotating water inlet assembly ensures that the water evenly washes the top screen surface, preventing small-size microplastics from being retained on the top large-aperture screen surface, thereby improving the accuracy of the later detection results. The multi-stage screen assembly device is provided with at least two levels of screens with different apertures. The water flowing into the multi-stage screen assembly device flows out from the outlet of the bottom water collection layer after passing through the screens with different apertures by gravity. Microplastic particles of different particle sizes are retained on the screen layer of the corresponding aperture. When a certain layer of screen is to be taken out to collect the retained material, the layer of screen is removed for processing, thereby realizing particle size classification and synchronous collection of microplastic particles in the water body, and entering the receiving bucket through the outlet of the multi-stage screen assembly device. By collecting the filtered water and using it for the later screen microplastic washing and collection work, the maximum efficiency of the sampled water body is achieved while the secondary filtration is performed.

[0012] The following is a preferred technical solution of the present invention:

[0013] The water inlet pipe is connected to a water pump for water intake. The system connecting pipes between the water inlet pipe, the water pump and the screen assembly are made of polytetrafluoroethylene tubes, and the joints, flow meters, and water valves are made of metal parts such as stainless steel or aluminum alloy to reduce the impact of plastic materials on the test results. The water to be sampled is introduced into the system through the water pump, and then enters the multi-stage screen assembly through the rotating water inlet assembly.

[0014] The water inlet pipe is connected with a flow meter and a water valve. The flow meter displays the flow rate of large sample water in the water inlet pipe, and the water valve is used to control the on-off of the large sample water in the water inlet pipe. A flow meter and a water valve are arranged between the water pump and the rotating water inlet assembly. The flow meter monitors the water inlet flow rate and the total filtration volume when the system is working, and the water valve controls the water inlet of the screen assembly. The sample water extracted by the water pump enters the water inlet pipe through the flow meter and the water valve, and then is introduced into the rotating drainage layer. It then rotates around the central axis of the device and is discharged into the multi-stage screen structure to ensure that the water inlet fully and evenly rinses the top screen surface, preventing small-particle microplastics from being retained on the top large-aperture screen surface and affecting the later counting results.

[0015] The multi-stage screen assembly device comprises:

[0016] vertical support columns;

[0017] A plurality of screen units are stacked and installed on the vertical support column in sequence, wherein screens with different apertures are arranged in the plurality of screen units, and each screen unit comprises a circular frame and a screen arranged at the bottom of the circular frame.

[0018] The plurality of screen units are mounted on the vertical support columns by bolt rings.

[0019] The water flowing into the multi-stage screen combination device relies on gravity to pass through each level of screen and then flows out from the outlet of the bottom water collection layer. Microplastic particles of different particle sizes are retained on the screen layers of corresponding apertures. Each level of the screen layer can be disassembled or raised and lowered along the vertical support column by adjusting the tightness of the bolt rings at both ends. To remove a certain layer of screen to collect the retained materials, it is only necessary to lift its upper component and remove the layer of screen for processing, thereby realizing the particle size classification and simultaneous collection of microplastic particles in the water.

[0020] A water level observation window is provided on the circular frame of the screen unit. The screen units of the multi-stage screen assembly device are composed of a hollow barrel-shaped stainless steel screen frame (i.e., a circular frame) and a stainless steel screen. A water level observation window is provided on the side wall of the circular frame, so that the filtration status of the sample water in the device can be observed in real time and the blockage of the screen can be discovered in time. The outer walls on both sides of the screen frame are connected to the vertical support columns by bolt rings. To prevent blockage during the screen filtration process, when the water level in the water level observation window is high, close the water valve in front of the water inlet pipe and then turn off the water pump. After the water level in the blocked screen layer stabilizes, lift the upper structure to an appropriate height as a whole, and use stainless steel tweezers to remove large pieces of non-plastic matter in the blocked screen layer or remove the screen layer. After collecting the retained materials, return the screen layer to its original position, restore the device to its original state and continue to pump and filter. After the sampling is completed, collect the retained materials in the screen again, and combine the collected materials in several times into the same container to achieve multiple collections under blockage conditions and ensure the complete collection of microplastic particles in large sample water bodies.

[0021] The stacking of the plurality of screen units is connected by a detachable sealed connection, and the detachable sealed connection is one of an internal and external threaded connection, a snap-fit ​​connection, a sleeve connection or an adhesive connection.

[0022] There are three multiple screen units, and the apertures of the screens in the multiple screen units are 3-8 mm, 80-120 μm, 10-30 μm from the top to the bottom of the multi-stage screen assembly device, and most preferably 5 mm, 100 μm, and 20 μm.

[0023] The rotating water inlet assembly is located at the top of the multi-stage screen assembly device, which facilitates water to pass through screens with different apertures by relying on gravity.

[0024] The rotating water inlet assembly comprises:

[0025] A motor support lifting frame is installed on the top of the multi-stage screen assembly device;

[0026] A reduction motor installed on the motor support lifting frame;

[0027] A connecting rod connected to the reduction motor;

[0028] And a rotary drainage layer fixed to the connecting rod, wherein the rotary drainage layer is installed in the screen unit at the top of the multi-stage screen assembly device.

[0029] The motor support lifting frame is connected to the vertical support column through bolt ring buckles.

[0030] The water outlet of the water inlet pipe is installed in the rotating drainage layer, and the reduction motor drives the rotating drainage layer to rotate through the connecting rod. The large sample water comes in from the water inlet pipe, and then enters the rotating drainage layer from the water outlet of the water inlet pipe. The rotating drainage layer rotates to guide the large sample water into each screen unit of the multi-stage screen combination device, ensuring that the incoming water evenly rinses the intercepted materials on the top screen surface (i.e., the screen unit at the top of the multi-stage screen combination device), preventing small-particle microplastics from accumulating and being retained on the top large-aperture screen surface, affecting the subsequent counting results.

[0031] The rotating drainage layer comprises: a circular frame and a rectangular drainage port arranged at the bottom of the circular frame, and the rectangular drainage port is arranged along the radial direction of the circular frame.

[0032] A dust cover is provided on the water inlet pipe at the position where the water inlet pipe is inserted into the top of the multi-stage screen assembly device.

[0033] The rotating water inlet assembly includes a water inlet pipe, a dust cover, a reduction motor, a motor support and lifting frame, a connecting rod and a rotating water leakage layer. One end of the water inlet pipe is connected to the water valve through a connecting pipe, and the other end is inserted into the rotating water leakage layer through a circular opening on the sealing top cover; the water inlet pipe and the motor support and lifting frame are connected to the vertical support column through bolt ring buckles, which is convenient for controlling the water inlet pipe and the reduction motor to rise and fall synchronously with the screen layer; a dust cover is set at the water inlet pipe insertion port of the top cover to reduce the pollution of the external environment to the test results; the rotating water leakage layer is in the shape of a hollow cylinder, contained in the top screen, and a rectangular water leakage port set along the radius is opened on the circular bottom layer; the reduction motor is located above the center of the circular top cover, and is connected to the bottom center of the rotating water leakage layer through a stainless steel connecting rod passing through the support frame, the top cover and the top cover, driving it to rotate around the rod axis at an appropriate speed.

[0034] A one-way valve is provided between the water outlet of the multi-stage screen assembly device and the receiving bucket.

[0035] The receiving bucket is provided with a drain port, and the bottom of the sealed stainless steel receiving bucket is provided with a drain port. After the system starts working, the drain port is kept open until there is 10L of water left to be filtered and then closed. The remaining collected water is stored in the stainless steel receiving bucket for later collection of flushing water required for intercepted materials by the sieves at all levels, thereby improving the utilization rate of the sampled water during the collection process.

[0036] The connecting pipe between the multi-stage screen combination water outlet and the stainless steel receiving barrel is made of stainless steel pipe, and the interface and one-way valve are made of stainless steel or aluminum alloy metal parts to avoid secondary contamination of the water collected in the stainless steel barrel by plastic materials, which will affect the subsequent sampling and counting results.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] 1. The present invention is suitable for the detection of microplastics in large sample water bodies. The blockage that is prone to occur during the sampling process can be discovered in time through the water level observation window on the wall of the sieve layer. By simply lifting and disassembling the sieve layer, large pieces of non-plastic substances can be collected or cleaned up and removed multiple times to solve the blockage problem conveniently and quickly.

[0039] 2. The water inlet to the top layer of the screen of the present invention is in the form of a motor-controlled rotation to evenly inlet water, ensuring that the water evenly rinses the top layer of the screen surface, preventing small-particle microplastics from being retained on the top layer of the large-aperture screen surface, and improving the accuracy of subsequent detection results.

[0040] 3. The present invention collects filtered water and uses it for subsequent screen microplastic flushing and collection work, thereby achieving maximum efficient utilization of the sampled water body during secondary filtration.

[0041] 4. All components of the present invention can be assembled and disassembled, and the entire system is convenient to carry and transport. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic side structural diagram of a system for synchronously collecting microplastics of multiple particle sizes in water bodies to prevent clogging according to an embodiment of the present invention;

[0043] Figure 2 This is a front structural schematic diagram of the anti-clogging system for synchronously collecting microplastics of multiple particle sizes in water according to an embodiment of the present invention;

[0044] Figure 3 It is a schematic structural diagram of a single-stage screen layer and connected bolt ring buckles according to an embodiment of the present invention;

[0045] Figure 4 A three-dimensional schematic diagram of a water inlet structure at the top of a screen according to an embodiment of the present invention;

[0046] Among them: 1. Water inlet pipe of water pump; 2. Water pump; 3. Digital flow meter; 4. Water valve; 5. Connecting pipe; 6. Motor support lifting frame; 7. Reducer motor; 8. Water inlet pipe; 9. Dust cover; 10. Top cover; 11. Vertical support column; 12. Screen layer; 13. Bolt ring; 14. Bottom water collecting layer; 15. Loading rack; 16. Water outlet; 17. Water outlet pipe; 18. One-way valve; 19. Stainless steel receiving bucket; 20. Drainage outlet; 21. Water level observation window; 22. Metal connecting rod; 23. Rotating drainage layer. DETAILED DESCRIPTION

[0047] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0048] In this embodiment, microplastic particles with a particle size of 20μm-5mm in the raw water of the water supply plant are collected. Since the content of microplastics in the raw water is relatively low, a large sample of water needs to be collected to improve the accuracy of the detection results. Therefore, the system filters 500L of water.

[0049] like Figure 1 , Figure 2 As shown, the anti-clogging water body multi-size microplastic synchronous collection system includes: an inlet pipe 1 (i.e., a water pump inlet pipe); a multi-stage screen assembly connected to the inlet pipe 1, wherein the multi-stage screen assembly is provided with at least two stages of screens with different apertures; a receiving bucket 19 (stainless steel receiving bucket 19) connected to the water outlet 16 of the multi-stage screen assembly; and a rotating water inlet assembly provided at the connection between the inlet pipe 1 and the multi-stage screen assembly. A water pump 2 is connected to the inlet pipe 1. A digital flowmeter 3 and a water valve 4 are connected to the inlet pipe 1.

[0050] The multi-stage screen assembly device comprises: a vertical support column 11;

[0051] Multiple screen units are stacked and installed on the vertical support column 11 in sequence. Screens with different apertures are arranged in the multiple screen units. Each screen unit (i.e., screen layer 12) includes a circular ring frame and a screen arranged at the bottom of the circular ring frame. Multiple screen units are installed on the vertical support column 11 through bolt ring buckles 13. A water level observation window 21 is opened on the circular ring frame of the screen unit. The stacking of multiple screen units adopts a detachable sealed connection, which is one of internal and external threaded connection, snap-fit ​​connection, sleeve connection or adhesive connection.

[0052] The rotating water inlet assembly includes: a motor support lifting frame 6 installed on the top of the multi-stage screen assembly device; a reduction motor 7 installed on the motor support lifting frame 6; a connecting rod 22 (i.e., a metal connecting rod 22) connected to the reduction motor 7; and a rotating water leakage layer 23 fixed to the connecting rod 22, the rotating water leakage layer 23 is installed in the screen unit on the top of the multi-stage screen assembly device, and the water outlet of the water inlet pipe 1 is installed in the rotating water leakage layer 23. The rotating water leakage layer 23 includes: a circular frame and a rectangular water leakage port arranged at the bottom of the circular frame, and the rectangular water leakage port is arranged along the radial direction of the circular frame.

[0053] The anti-clogging system for synchronously collecting microplastics of multiple sizes in water in this embodiment includes a water pump 2, a flow meter 3, a water valve 4, a rotating water inlet assembly, a liftable and detachable multi-stage stainless steel screen assembly 12-14, a stainless steel water outlet pipe 17, and a closed stainless steel receiving bucket 19 with a drain port 20. The rotating water inlet assembly is located at the top of the multi-stage screen assembly. The top cover 10 in the multi-stage screen assembly is connected to the upper end of the top screen and the upper and lower screen layers by socket connection. Bolt buckles 13 are arranged at both ends of each layer of the screen to connect with the vertical support column 11. For specific connection methods, see Figure 3 The positional relationship of each screen layer can be adjusted by the bolt ring 13 to make the socketing between the screen layers tighter. In order to avoid leakage and loss of microplastics, a rubber sealing ring can be added at the socketing; the present embodiment arranges a three-level screen combination with different apertures, the top screen aperture is 5mm, the middle screen aperture is 100μm, and the bottom screen aperture is 20μm. A glass observation window 21 is opened on the wall of each screen layer; a stainless steel water outlet pipe 17 connects the screen combination and the receiving bucket 19, and a one-way valve 18 is provided in the middle, both of which are connected by internal and external threads.

[0054] like Figure 4 As shown, the rotary water inlet assembly includes a water inlet pipe 8, a dust cover 9, a reduction motor 7, a motor support and lifting frame 6, a metal connecting rod 22 and a rotary water leakage layer 23. One end of the water inlet pipe 8 is connected to the water valve 4 through a connecting pipe, and the other end is inserted into the rotary water leakage layer 23 through a circular opening on the sealing top cover 10; the water inlet pipe 8 and the motor support and lifting frame 6 are connected to the vertical support column 11 through a bolt ring buckle 13, which is convenient for controlling the water inlet pipe 8 and the reduction motor 7 to rise and fall synchronously with the screen layer 12; a dust cover 9 is set at the water inlet pipe insertion port of the top cover 10 to reduce the pollution of the external environment to the detection results.

[0055] In this embodiment, the anti-clogging water body multi-size microplastic synchronous collection system, the specific collection steps are as follows:

[0056] 1) Assemble the device system as described above and place it on a flat work surface, start the reduction motor 7 in the rotating water inlet assembly to drive the rotating drainage layer 23 to rotate, and test the stability of the overall structure of the system. If the screen assembly tilts or shakes, check and adjust the bolt ring 13 and the vertical support column 11 in time to achieve effective fixation. In addition, the stability can be improved by placing appropriate weights on the carrier 15.

[0057] 2) After confirming that the system is stable as a whole, insert the head of the water pump inlet pipe 1 into the water body at the sampling point, open the drain port 20 and all valves, start the water pump 2, and start the collection work. The water sample at the sampling point passes through the water pump 2, flowmeter 3, and water valve 4 in turn, enters the rotating water inlet assembly, and is introduced into the multi-stage screen structure while rotating around the central axis of the device to ensure that the incoming water evenly washes the intercepted materials on the top screen surface, and prevents small-sized microplastics from accumulating and being retained on the top large-aperture screen surface, affecting the later counting results. The water sample relies on gravity to pass through the screen layers with apertures of 5mm, 100μm, and 20μm in turn, and then flows out from the outlet 16 of the bottom water collection layer 14, and finally flows into the stainless steel receiving bucket 19. At this time, microplastic particles of different particle sizes are trapped on the screen layers with corresponding apertures.

[0058] 3) The water inflow and total filtration volume during the operation of the system are monitored by the digital flowmeter 3, and the blockage phenomenon during the sampling process is monitored by the water level observation window 22 of each level of the screen layer 12. When the water level in the water level observation window 21 of a certain level of the screen layer is high, blockage may occur. First, turn off the top reduction motor 7 and the water valve 4, and then turn off the water pump 2. After the water level in the blocked screen layer is stable, adjust the bolt ring 13 to lift the overall structure above the layer to an appropriate height, use stainless steel tweezers to remove the large non-plastic material in the blocked screen layer or adjust the bolt ring of the screen layer to remove the screen layer, rinse and collect all the retained materials in it into the corresponding container, and then return the screen layer to its original position, and then turn on the reduction motor 7 and the water valve 4 again, and then turn on the water pump 2 to continue pumping and filtering.

[0059] 4) When there are 10L of water left to be filtered, close the drain port 20 and save the remaining collected water in the stainless steel receiving bucket for later use as flushing water for collecting the retained materials at various levels of screens, thereby improving the utilization rate of the sampled water during the collection process.

[0060] 5) After the volume of the filtered water has reached the sampling volume requirement, first turn off the reduction motor 7 and the water valve 4, then turn off the water pump 2, and after there is no more water in each mesh layer, adjust the bolt ring buckle 13 of the structure above the top mesh layer to raise it to an appropriate height. Open the drain port 20, use the wash bottle to receive the remaining filtered water, then remove the mesh layers of each aperture in turn, use the wash bottle to clean and discard the retained materials in the 5mm mesh layer, and rinse and collect the retained materials in the remaining mesh layers into the corresponding containers.

[0061] 6) After the collection is completed, the collection system is disassembled, each water flow structure is cleaned, and the containers containing microplastics of various particle sizes are sent to the laboratory for further processing in a sealed and low-temperature environment.

[0062] The above embodiments only illustrate the technical solutions of the present invention and are not intended to limit the patent protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A system for synchronously collecting microplastics of multiple particle sizes in water bodies that prevents clogging, characterized in that: include: Water inlet pipe: A multi-stage screen assembly device connected to the water inlet pipe, wherein the multi-stage screen assembly device is provided with at least two stages of screens with different apertures; A receiving bucket connected to the water outlet of the multi-stage screen assembly; and, a rotating water inlet assembly disposed at the connection between the water inlet pipe and the multi-stage screen assembly device; The water inlet pipe is connected to a water pump, and the water inlet pipe is connected to a flow meter and a water valve; The multi-stage screen assembly device comprises: vertical support columns; A plurality of screen units are stacked and installed on the vertical support column in sequence, wherein screens with different apertures are arranged in the plurality of screen units, and each screen unit comprises a circular ring frame and a screen arranged at the bottom of the circular ring frame; The plurality of screen units are mounted on the vertical support column by bolts and rings; A water level observation window is provided on the circular ring frame of the screen unit; The stacking of the plurality of screen units is connected by a detachable sealed connection, wherein the detachable sealed connection is one of an internal and external threaded connection, a snap-fit ​​connection, a sleeve connection or an adhesive connection; The rotating water inlet assembly comprises: A motor support lifting frame is installed on the top of the multi-stage screen assembly device; A reduction motor installed on the motor support lifting frame; A connecting rod connected to the reduction motor; and a rotary drainage layer fixed to the connecting rod, the rotary drainage layer being installed in the screen unit at the top of the multi-stage screen assembly device, and the water outlet of the water inlet pipe being installed in the rotary drainage layer; The rotating drainage layer comprises: a circular frame and a rectangular drainage port arranged at the bottom of the circular frame, and the rectangular drainage port is arranged along the radial direction of the circular frame.

2. The anti-clogging water multi-size microplastic synchronous collection system according to claim 1 is characterized in that: There are three multiple screen units, and the apertures of the screens in the multiple screen units are 3-8 mm, 80-120 μm, and 10-30 μm from the top to the bottom of the multi-stage screen assembly device.

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