A portable in-situ water microplastic graded sampling system and control method

Abstract

The present invention relates to a portable in-situ water microplastic graded sampling system and control method, wherein a water inlet is embedded above the side wall of the sampling bracket, and the water inlet is connected to a filtering mechanism through a solenoid valve; its output end is connected to a water outlet, and the water outlet is embedded below the side wall of the sampling bracket, and a water pump is arranged between the water outlet and the filtering mechanism; a liquid level sensor is arranged inside the sampling bracket on the same horizontal line as the water inlet, and the liquid level sensor is connected to a data acquisition and controller; a flow meter is arranged between the solenoid valve and the filtering device, and the flow meter is connected to the data acquisition and controller, and the data acquisition and controller is connected to the solenoid valve and the water pump, and the solenoid valve and the water pump are controlled according to a flow volume signal and a liquid level height signal. The present invention can pre-set parameters such as sampling depth and sampling volume to realize fully automatic collection of microplastics, and can also manually control the collection process, monitor the underwater collection state of the sample in real time, and realize accurate quantitative collection of water microplastic samples.

Description

Technical Field

[0001] The present invention relates to the technical field of marine environmental pollution research, and in particular to a portable in-situ water microplastic graded sampling system and a control method. Background Art

[0002] Microplastics are called "PM2.5" in the ocean, and refer to plastic particles smaller than 5mm in size. Due to their small particle size, microplastics are easily ingested by marine organisms and accumulated in various marine organisms. Exposure to microplastics can inhibit marine organisms from ingesting microplastics, produce oxidative stress on marine organisms, induce their immune response, and even lead to decreased fertility and abnormal embryonic development of some organisms, affecting the replenishment of their biological populations. Therefore, microplastics pose a potential threat to marine ecosystems. Studying the abundance and distribution of microplastics is of great significance for clarifying the fate mechanism of microplastics in the marine environment, and also provides a scientific basis for assessing the pollution level of microplastics in my country and their potential ecological risks.

[0003] At present, the horizontal trawling method is commonly used to collect microplastics in water bodies. The depth error of the collected water layer is large, making it difficult to conduct cross-sectional distribution research on microplastics. In addition, the trawling process is easily affected by wind and waves and waves generated by the hull, and the net is easy to be damaged and tilted. The flow meter at the net mouth has poor accuracy, resulting in unstable water intake at the net mouth, large deviation in the volume of the trawling water body, and inaccurate calculation results. The commonly used sampling nets are large in size, and microplastic samples are easy to adhere to the net or sieve, which can easily lead to unclean rinsing and serious sample residue, which directly affects the quantitative analysis of the samples. In addition, for microplastic samples of different particle sizes, it is necessary to replace nets with different mesh sizes and trawle multiple times, resulting in poor uniformity of graded samples and waste of manpower and material resources. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a portable in-situ water microplastic graded sampling system and control method.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0006] A portable in-situ water microplastic graded sampling system includes a sampling bracket 18, which is characterized in that: a water inlet 1 is embedded above the side wall of the sampling bracket 18, and the water inlet 1 is connected to a filtering mechanism through a solenoid valve 3; the output end of the filtering mechanism is connected to a water outlet 8, and the water outlet 8 is embedded below the side wall of the sampling bracket 18, and a water pump 7 is arranged between the water outlet 8 and the filtering mechanism; a liquid level sensor 15 is arranged inside the sampling bracket 18 on the same horizontal line as the water inlet 1, and the liquid level sensor 15 is connected to a data acquisition and controller 11, and a liquid level height signal is collected and sent to the data acquisition and controller 11; a flow meter 4 is arranged between the solenoid valve 3 and the filtering device, and the flow meter 4 is connected to the data acquisition and controller 11, and a current flow volume signal is collected and sent to the data acquisition and controller 11, and the data acquisition and controller 11 is connected to the solenoid valve 3 and the water pump 7, and the solenoid valve 3 and the water pump 7 are controlled according to the flow volume signal and the liquid level height signal.

[0007] The filtering mechanism comprises a filter barrel 5, a filter barrel top cover 19 and a filter 6;

[0008] The filter barrel top cover 19 is fixed to the filter barrel 5 by a lock, the filter barrel 5 and the filter barrel top cover 19 are sealed by a sealing gasket 28, and an injection port 27 is provided in the middle part of the filter barrel top cover 19;

[0009] The filter 6 includes several levels of filtering devices, and from top to bottom, the filtering accuracy of the next level of filtering devices is higher than that of the previous level;

[0010] A support block 29 is provided below the inner wall of the filter barrel 5, and abuts against the lowest filter device through an "O"-shaped sealing ring 26, for supporting the lowest filter device so that the screen of the lowest filter device maintains a certain distance from the bottom of the filter barrel.

[0011] The filtering device comprises an inner tank with different diameters at the top and bottom, and the diameter of the upper part of the inner tank is larger than the diameter of the lower part. A screen 24 is integrally formed at the lower part of the inner tank, and a filter membrane or screen silk 22 is arranged above the screen 24. The filter membrane or screen silk 22 is fixed by a gasket 23 and a retaining spring 25.

[0012] The lower inner shell of the upper filter device is inserted into the upper inner shell of the lower filter device, and an O-ring 26 is provided between the outer wall of the lower inner shell of the upper filter device and the inner wall of the upper inner shell of the lower filter device for sealing.

[0013] The injection port 27 is a mesh injection port.

[0014] A sample inlet screen 2 is arranged at the front end of the water inlet 1 to prevent large particles from entering the pipeline, and the aperture range of the screen is 4 mm to 6 mm.

[0015] The data acquisition and controller 11 is sealed in the data acquisition and control chamber 10, wherein the data acquisition and controller 11 adopts a PLC programmable controller to collect and automatically control system data.

[0016] It also includes a battery pack 13, which is sealed in the battery compartment 12 and connected to the data acquisition and controller 11, and is used to power the system when it is underwater.

[0017] It also includes an aquatic power supply plug connected to the data acquisition and controller 11 through a power supply cable 31, which is used to power the system when it is on water, wherein the power supply cable 31 enters the data acquisition and control compartment 10 after passing through the waterproof plug 16 and is connected to the data acquisition and controller 11.

[0018] It also includes a handheld controller 9 connected to the data acquisition and controller 11 through a communication cable 30, sending a control signal to the data acquisition and controller 11, and externally controlling the system; wherein the communication cable 30 enters the data acquisition and control compartment 10 through a waterproof plug 16 and is connected to the data acquisition and controller 11.

[0019] The control method of the portable in-situ water microplastic graded sampling system includes the following processes:

[0020] The sampling system enters the water, and the liquid level sensor 15 feeds back the collected liquid level height signal to the data acquisition and controller 11 in real time, and transmits the liquid level height signal to the handheld controller 9 in real time through the communication cable 30;

[0021] When the set depth is reached, the handheld controller 9 gives an alarm, and the sampling system stops lowering and maintains the depth;

[0022] Set the sampling volume, start time, flow setting value and warning time. When the start time is reached, the system automatically starts to collect samples. The flow meter 4 transmits the flow volume signal to the data acquisition and controller 11 in real time. When the set sampling volume is reached, the system automatically shuts down.

[0023] If the flow data is less than the flow setting value for more than the warning time, the filter mechanism is considered to be blocked, the system is automatically shut down, and the sample volume is stored according to the actual sample volume.

[0024] The present invention has the following beneficial effects and advantages:

[0025] 1. The present invention is provided with three layers of filters, which can be equipped with screens, filter membranes and sieve silks with different apertures to achieve graded filtration of samples;

[0026] 2. The present invention can realize the in-situ fixed-depth collection of water microplastic samples through software control, and can realize the accurate quantitative collection of water microplastic samples by combining the corresponding designs of solenoid valves, flow meters, etc.;

[0027] 3. The present invention can pre-set parameters such as sampling depth and sampling volume to achieve fully automatic collection of microplastics, and can also manually control the collection process and monitor the underwater collection status of samples in real time;

[0028] 4. The water inlet of the present invention is fixed on the upper part of the sampling bracket and is located at the same horizontal line as the liquid level sensor, and the water outlet is fixed on the lower part of the sampling bracket, which effectively avoids the disturbance and influence of the water outlet on the water body at the water inlet;

[0029] 5. The top cover of the filter barrel of the present invention is fixed to the filter barrel by a lock buckle, which can be easily disassembled, and is convenient for installing and removing the filter;

[0030] 6. The present invention can ensure that all samples pass through each filter through the design of the sealing pad and the sealing ring, thereby ensuring the uniformity of graded sample sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a system structure diagram of the present invention;

[0032] Figure 2 It is a schematic diagram of the filtering mechanism of the present invention;

[0033] Figure 3 is a flow chart of the control method of the present invention;

[0034] Among them, 1 is the water inlet, 2 is the sample inlet screen, 3 is the solenoid valve, 4 is the flow meter, 5 is the filter barrel, 6 is the filter, 7 is the water pump, 8 is the water outlet, 9 is the handheld controller, 10 is the underwater data acquisition and control compartment, 11 is the data acquisition and controller, 12 is the battery compartment, 13 is the battery pack, 14 is the water power supply connector, 15 is the liquid level sensor, 16 is the waterproof connector, 17 is the data connection line, 18 is the sampling bracket, 19 is the sampling barrel top cover, 20 and 21 are locks, 22 is the filter membrane or sieve silk, 23 is a gasket, 24 is a sieve, 25 is a retaining spring, 26 is an "O" ring, 27 is the sample inlet, 28 is a sealing pad, 29 is a support block, 30 is a communication cable, 31 is a power supply cable, 32 is a lifting and weighing cable, 33 is a first filtering device, 34 is a second filtering device, and 35 is a third filtering device. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0036] The portable in-situ microplastic graded sampling system for water bodies consists of a graded sampling module, an underwater data acquisition and control module, a power supply module, a handheld controller, a liquid level sensor, a sampling bracket, etc. The entire system is controlled by software and can achieve in-situ filtration, precise quantification and graded collection of microplastics in water bodies. Parameters such as sampling depth, sampling volume, and sampling time can be pre-set, and data such as sampling time, volume, pressure value, and flow rate can also be automatically recorded.

[0037] The graded sampling module consists of a pump, a flow meter, a solenoid valve, a filter barrel, a filter, pipes and fittings. It is characterized in that the sampling water inlet is equipped with a solenoid valve and a flow meter. The water inlet and the depth sensor are located on the same horizontal line. When the preset depth is reached, the solenoid valve and the flow meter are opened. Under the continuous extraction of the water pump at the outlet, the sample is intercepted on the screen, sieve silk or filter membrane of the multi-stage filter. Therefore, this system can realize accurate depth collection, accurately control the sampling volume, and realize graded collection of samples. A three-layer filter stacking design is adopted. During the sampling process, the microplastic samples in the water body are accumulated on a multi-layer screen, sieve silk or filter membrane with a diameter of 100mm. Screens, sieve silk or filter membranes with different apertures can be configured as needed to realize the graded collection of microplastic samples of different sizes in the water body. A sealing design is made between each layer of filters and between the filter and the top cover of the filter barrel to ensure the uniformity of graded sample sampling and prevent cross contamination. The screen on the filter can not only be used to filter samples, but also as a filter bracket. By adding gaskets and retaining springs to the upper part of the screen, the filter membrane or sieve silk can be fixed to meet various sample collection and testing needs.

[0038] The underwater data acquisition and control module has multiple functions such as data acquisition, data feedback and control. That is, the module is connected to the underwater water pump, solenoid valve, flow meter and liquid level sensor, and can control the opening and closing of the sampling body according to the instructions, that is, control the steering of the solenoid valve, the opening and closing of the water pump, and the data acquisition and control of the flow meter and liquid level sensor. The underwater data acquisition and control module is connected to the handheld controller by wire, realizing the wired communication between the handheld controller and the underwater equipment, and can timely control and grasp the underwater sampling process and status.

[0039] The power supply module adopts a dual power supply mode of switching between battery compartment self-capacity power supply and shipboard power supply. That is, if the sampling ship has no power supply, the instrument is powered by the underwater battery compartment. If the sampling ship can supply power, the instrument can switch to the power supply on board.

[0040] The filter barrel inlet adopts a spray design to ensure that the collected microplastics are evenly distributed over the entire surface of the filter, membrane or sieve.

[0041] Selecting a variable frequency water pump to adjust the flow rate of the water pump according to the pore size of the screen, screen silk or filter membrane can effectively prevent blockage.

[0042] The water enters the filter directly instead of passing through the pump first, so as to avoid the influence of the mechanical force of the pump on the sample particle size and improve the accuracy of sample collection. The underwater devices are all sealed with "O" rings.

[0043] The connectors of the underwater power line, data transmission line, etc. are all waterproof connectors.

[0044] The sampler body, pipelines, fittings, etc. are all made of metal materials such as stainless steel, which can effectively reduce the contamination of microplastic samples by plastic materials.

[0045] The sampling system can be deployed individually or multiple samplers can be deployed in series to collect samples at different depths at the same time and obtain samples from the entire profile. The CTD instrument can also be integrated into the system bracket and deployed together to obtain environmental parameter data at the same time.

[0046] Example:

[0047] like Figure 1 Shown is a system structure diagram of the present invention.

[0048] The portable in-situ water microplastic graded sampling system consists of a graded sampling module, an underwater data acquisition and control module, a power supply module, a handheld controller, a depth sensor, a sampling bracket, etc. The graded sampling module consists of a water pump 7, a flow meter 4, a solenoid valve 3, a filter barrel 5, a filter 6, a water inlet 1, a water outlet 8, pipes and fittings, etc. The underwater data acquisition and control module consists of an underwater data acquisition and control chamber 10, a data acquisition and controller 11, a waterproof connector 16 and various data connection lines 17. The underwater data acquisition and control module is connected to the solenoid valve 3, the flow meter 4, the water pump 7, the liquid level sensor 15 and the battery pack 13 through various data lines 17; it is connected to the handheld controller 9 through a communication cable 30, and is connected to the water power supply connector 14 through a power supply cable 31.

[0049] The data acquisition and controller 11 can control the opening and closing of the solenoid valve 3 and the water pump 7 according to the instructions of the handheld controller 9, the liquid level height signal of the liquid level sensor 15, and the flow volume signal of the flow meter 4. The data acquisition and controller 11 can determine whether to use the underwater battery pack 13 for power supply according to whether the water power supply connector 14 is powered or not.

[0050] The water inlet 1 is fixed to the upper part of the sampling bracket 18, and is located at the same horizontal line as the liquid level sensor 15. The water outlet 8 is fixed to the lower part of the sampling bracket 18, which effectively avoids the disturbance and influence of the water outlet on the water body at the water inlet. At the same time, the sampling port partition 2 is added to the front end of the sampling port 1, and the aperture of the partition can be selected, for example, 5mm aperture, to prevent large particles from entering the pipeline, affecting sampling and possibly blocking the pipeline.

[0051] The filter barrel 5, the underwater data collection and control compartment 10, and the battery compartment 12 are all sealed compartments, which are sealed by an "O" ring or a sealing gasket.

[0052] In order to avoid entanglement and increase tensile strength, the communication cable 30, the power supply cable 31 and the lifting and weighing cable 32 are integrated into one. If the sampling ship has no power supply and needs to be powered by underwater batteries, the power supply cable 31 can be removed and the waterproof plug 16 can be waterproofed.

[0053] like Figure 2 Shown is a schematic diagram of the filtering mechanism of the present invention.

[0054] A three-layer filter 6 stacking design is adopted, which includes the first filter device 33, the second filter device 34, and the third filter device 35 from top to bottom. In principle, the filter aperture is as follows: the aperture or filter membrane or sieve silk of the first filter device 33 > the aperture or filter membrane or sieve silk of the second filter device 34 > the aperture or filter membrane or sieve silk of the third filter device 35.

[0055] The filter barrel top cover 19 is fixed to the filter barrel 5 by locks 20 and 21, and can be easily disassembled, so as to facilitate the installation and removal of the filter. The filter barrel top cover 19 is sealed with the filter barrel 5 by a sealing gasket 28, and the first filter device 33 is sealed with the filter barrel top cover 19 by a sealing gasket 28 to prevent the water sample from flowing directly along the gap between the first filter device 33 and the filter barrel 5 without passing through filters at all levels. The first filter device 33, the second filter device 34, and the third filter device 35 are all designed with two O-rings 26, which are mainly for sealing between the upper and lower filters to prevent water from overflowing the filter and flowing directly out of the gap between the filter and the filter barrel 5 without passing through the lower filter. Through the design of the sealing gasket 28 and the sealing ring 26, it can be ensured that all samples pass through each filter, thereby ensuring the uniformity of graded sample sampling.

[0056] The screen 24 and the filter 6 are designed as one body, that is, the screen 24 is a part of the filter 6. The filter 6 can be used not only to filter samples, but also as a filter support. By adding a smooth gasket 23 and a spring 25 on the upper part of the screen 24, the filter membranes or sieve silks 22 with different pore sizes can be fixed, and the graded collection of microplastic samples of different sizes in the water can be realized to meet the needs of various sample collection and detection.

[0057] The sample inlet 27 fixed to the top cover 19 of the filter barrel adopts a mesh injection port design to ensure that the collected microplastics are evenly distributed on the entire surface of the filter screen, filter membrane or sieve silk.

[0058] like Figure 3 Shown is a flow chart of the control method of the present invention.

[0059] This system can realize manual setting and fully automatic operation. The handheld controller 9 and the data acquisition and controller 11 are used to control the actions of each component, receive feedback signals and make operation instructions. The handheld controller 9 can be used to select the sampling method. The sampling depth, sampling volume and other parameters can be preset to select fully automatic operations such as fixed volume sampling and fixed time sampling. The opening and closing of the underwater equipment can also be manually controlled. Figure 3 The working process of a portable in-situ water microplastic classification sampling system of the present invention is as follows:

[0060] First, determine whether it is powered by underwater batteries or surface power according to the availability of power on site; install a three-layer filter according to sample collection and monitoring requirements, and check the sealing of all underwater equipment.

[0061] Secondly, the flow rate of the water pump 7 is set according to the pore size of the filter screen / filter membrane / sieve silk; and the sampling depth value of the sampling system is set.

[0062] When the sampling system enters the water, the depth sensor 15 transmits the sensed depth signal to the data acquisition and controller 11 in real time, and transmits the depth signal to the handheld controller 9 in real time through the communication cable 30. When the set depth is reached, the handheld controller 9 gives an alarm, and the crew on board stops the sampling system from continuing to lower and maintain this depth.

[0063] At this time or before launching, you can choose whether to let the system automatically collect according to the preset program, or whether the crew on board manually controls the opening and closing of the sampling system. If the user wants the system to collect automatically, the sampling volume, start time and flow setting value can be set. After the start time is reached, the system automatically turns on to collect samples. The flow meter 4 transmits the flow volume signal to the data acquisition and controller 11 in real time. After reaching the set sampling volume, the system automatically turns off. If the flow data is less than the set value for more than 1 minute, it is considered that the filter is blocked, the system automatically shuts down, and the sampling volume is stored according to the actual sampling volume. If the user wants to manually control the collection process, just click on the system to open and close at any time. During the collection process, the personnel should keep an eye on the flow changes in real time to avoid blockage and damage to the water pump.

[0064] After the system has finished collecting, it waits for recycling. At this time, the data such as sampling time, volume, pressure value and flow rate are automatically stored in the data acquisition and controller 11 and can be downloaded after recycling.

Claims

1. A portable in-situ water microplastic classification sampling system, comprising a sampling bracket (18), characterized in that: A water inlet (1) is embedded above the side wall of the sampling bracket (18), and the water inlet (1) is connected to the filtering mechanism through the electromagnetic valve (3); the output end of the filtering mechanism is connected to the water outlet (8), and the water outlet (8) is embedded below the side wall of the sampling bracket (18), and a water pump (7) is arranged between the water outlet (8) and the filtering mechanism; a liquid level sensor (15) is arranged inside the sampling bracket (18) on the same horizontal line as the water inlet (1), and the liquid level sensor (15) is connected to the data acquisition and controller (11) to collect a liquid level height signal and send it to the data acquisition and controller (11); a flow meter (4) is arranged between the electromagnetic valve (3) and the filtering device, and the flow meter (4) is connected to the data acquisition and controller (11) to collect a current flow volume signal and send it to the data acquisition and controller (11); the data acquisition and controller (11) is connected to the electromagnetic valve (3) and the water pump (7), and controls the electromagnetic valve (3) and the water pump (7) according to the flow volume signal and the liquid level height signal; The filtering mechanism comprises a filter barrel (5), a filter barrel top cover (19) and a filter (6); wherein the filter barrel top cover (19) is fixed to the filter barrel (5) by a lock, the filter barrel (5) and the filter barrel top cover (19) are sealed by a sealing gasket (28), and a sample inlet (27) is provided in the middle portion of the filter barrel top cover (19); The filter (6) includes a plurality of filter devices, and from top to bottom, the filtering accuracy of the filter device at the next level is higher than that of the filter device at the previous level; A support block (29) is provided below the inner wall of the filter barrel (5) and abuts against the lowest level filter device via an "O"-shaped sealing ring (26) to support the lowest level filter device so that the screen of the lowest level filter device maintains a certain distance from the bottom of the filter barrel; The filtering device comprises an inner container with unequal upper and lower diameters, wherein the diameter of the upper half of the inner container is larger than the diameter of the lower half, a screen (24) is integrally formed at the lower part of the inner container, a filter membrane or a screen silk (22) is arranged above the screen (24), and the filter membrane or the screen silk (22) is fixed by a gasket (23) and a retaining spring (25); The lower half of the inner liner of the upper filter device is inserted into the upper half of the inner liner of the lower filter device, and an "O"-shaped sealing ring (26) is provided between the outer wall of the lower half of the inner liner of the upper filter device and the inner wall of the upper half of the inner liner of the lower filter device for sealing; Each of the plurality of filter devices is designed with two "O"-shaped sealing rings (26) to seal between the upper and lower filter devices and prevent water from overflowing the filter device and flowing directly out from the gap between the filter device and the filter barrel (5) without passing through the lower filter; The injection port (27) is a mesh injection port; A sample inlet screen (2) is arranged at the front end of the water inlet (1) to prevent large particles from entering the pipeline, and the pore size range of the screen is 4 mm to 6 mm.

2. The portable in-situ water microplastic graded sampling system according to claim 1 is characterized by: The data acquisition and controller (11) is sealed in the data acquisition and control chamber (10), wherein the data acquisition and controller (11) uses a PLC programmable controller to collect and automatically control system data.

3. The portable in-situ water microplastic graded sampling system according to claim 1 is characterized in that: It also includes a battery pack (13), which is sealed in the battery compartment (12) and connected to the data acquisition and controller (11) and is used to power the system when in an underwater state.

4. The portable in-situ water microplastic graded sampling system according to claim 1 is characterized by: It also includes an aquatic power supply plug connected to the data acquisition and controller (11) via a power supply cable (31) for supplying power to the system when in an aquatic state, wherein the power supply cable (31) enters the data acquisition and control compartment (10) through a waterproof plug (16) and is connected to the data acquisition and controller (11).

5. The portable in-situ water microplastic graded sampling system according to claim 1 is characterized by: The system also includes a handheld controller (9) connected to the data acquisition and controller (11) via a communication cable (30) to send a control signal to the data acquisition and controller (11) to perform external control on the system; wherein the communication cable (30) enters the data acquisition and control compartment (10) through a waterproof plug (16) to be connected to the data acquisition and controller (11).

6. The control method of the system according to any one of claims 1 to 5, characterized in that: The process includes: The sampling system is filled with water, and the liquid level sensor (15) feeds back the collected liquid level height signal to the data acquisition and controller (11) in real time, and transmits the liquid level height signal to the handheld controller (9) in real time through the communication cable (30); When the set depth is reached, the handheld controller (9) gives an alarm, and the sampling system stops lowering and maintains the depth; The sampling volume, start time, flow setting value and warning time are set. When the start time is reached, the system automatically starts to collect samples. The flow meter (4) transmits the flow volume signal to the data acquisition and controller (11) in real time. When the set sampling volume is reached, the system automatically shuts down. If the flow data is less than the flow setting value for more than the warning time, the filter mechanism is considered to be blocked, the system is automatically shut down, and the sample volume is stored according to the actual sample volume.

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