PLC full-automatic online sampling control system and method for water supply quality

Abstract

The invention discloses a PLC full-automatic online sampling control system and method for water supply quality. The PLC full-automatic online sampling control system comprises a PLC control unit, a sampling module, a refrigeration module and a fixing structure, the fixing structure adopts a waterproof and rust-proof metal frame and is detachably fixed on a wall body or a sampling point bracket; the sampling module comprises a water pump, a filter and a special filter element for two insects which are connected in sequence; the effective filtering aperture of the filter element is 1-5 microns; the PLC control unit monitors the accumulated flow of the sampling module in real time through a flowmeter, and when the accumulated flow reaches a preset volume, a water pump power supply is automatically cut off; and the refrigeration module is integrated with a semiconductor refrigeration device and a temperature sensor and is used for maintaining the temperature of the special filter element storage bin for the two insects at 0-4 DEG C. According to the full-automatic online sampling control system for giardia and cryptosporidium, personnel nursing is not needed in the whole process, strict quantification and automation are achieved, automatic collection and treatment of water samples are achieved, the detection efficiency and accuracy are improved, and powerful support is provided for prevention, control and early warning of parasitic diseases of water supply quality.

Description

Technical Field

[0001] The present invention relates to the technical field of water quality detection, and in particular to a PLC fully automatic online sampling control system and method for supply water quality. Background Art

[0002] The "Standards for Drinking Water Quality" and "Standards for Urban Water Supply Quality" clearly define requirements for testing for Giardia and Cryptosporidium in factory-leaving water. Two sampling methods are currently used for factory-leaving water testing: one requires personnel to collect up to 100 liters of water samples at a sampling point and bring them back to the laboratory for enrichment and filtration. This process is not only time-consuming and labor-intensive, but also consumes significant space and time resources in both the sampling vehicle and the laboratory. Furthermore, since water samples cannot be consistently refrigerated at 0-4 degrees Celsius during transportation and storage, this can lead to decreased parasite activity or morphological changes in the samples, affecting the accuracy of the test results.

[0003] Another method is on-site sampling. Using a dedicated, portable on-site sampling device, 100L of water samples are filtered at the sampling point, concentrated on the filter element, and then refrigerated and taken back to the laboratory. While this reduces the hassle of transporting water samples to some extent, existing equipment still has shortcomings in terms of automation and portability. For example, samplers need to carry bulky sampling devices to the site for filtering operations, which consumes manpower and material resources and limits the flexibility of sampling locations. Furthermore, because existing equipment cannot achieve automatic collection functions, the sampling process still requires human supervision, which undoubtedly increases labor and time costs. Therefore, an automated and intelligent sampling control system is urgently needed to solve the above problems. Summary of the Invention

[0004] In order to solve at least one of the technical problems mentioned above, the present invention provides a PLC fully automated online sampling control system and method for water quality.

[0005] In a first aspect, the present invention provides a PLC fully automated online sampling and control system for water quality, the system comprising:

[0006] PLC control unit, sampling module, refrigeration module and fixed structure;

[0007] The fixed structure adopts a waterproof and rust-proof metal frame, which can be detachably fixed to the wall or the sampling point bracket;

[0008] The sampling module includes a water pump, a filter and two insect-specific filter elements connected in sequence; the effective filtration pore size of the filter element is 1-5 microns;

[0009] The PLC control unit monitors the cumulative flow of the sampling module in real time through a flow meter, and automatically cuts off the power supply of the water pump when the cumulative flow reaches a preset volume;

[0010] The refrigeration module is integrated with a semiconductor refrigeration device and a temperature sensor to maintain the temperature of the two insect-specific filter storage bin at 0-4°C.

[0011] In one embodiment, the refrigeration module adopts a double-layer vacuum insulation structure, with a phase change energy storage material layer provided on the outer layer, which can maintain a low-temperature environment for more than 8 hours in the event of a power outage.

[0012] In one embodiment, the two-worm dedicated filter element is made of polycarbonate, has a porosity greater than 85%, and an effective filtration area greater than 200 cm².

[0013] In one embodiment, the PLC control unit is integrated with a wireless communication module for remote parameter setting, status monitoring and abnormality alarm functions.

[0014] In one embodiment, the fixed structure is equipped with a multi-directional adjustment bracket, allowing the sampling control system to be installed at an angle adjusted within a range of ±15° in the vertical direction.

[0015] In one embodiment, the refrigeration module further integrates a temperature control and enrichment module, which has a filter chamber with a vacuum interlayer, a built-in compressor refrigeration plate and a phase change material layer, and starts graded temperature control according to the temperature data of the sampled water quality.

[0016] In one embodiment, the PLC control unit further integrates a dynamic adjustment module for:

[0017] Establish a turbidity-flow mapping table to divide turbidity values into different levels and match them with corresponding flow rates;

[0018] Monitor the changes in turbidity level and use the preset acceleration gradient flow rate when the turbidity level changes.

[0019] In one embodiment, the dynamic adjustment module is further configured to generate a dynamic pressure difference compensation value based on the actual flow rate actually collected and the preset flow rate, so as to correct the water pump operating parameters during subsequent sampling.

[0020] In a second aspect, the present invention further provides a PLC fully automated online sampling control method for water supply quality, which is applied to the PLC fully automated online sampling control system for water supply quality as described in any one of the first aspects, and the method comprises:

[0021] Setting sampling parameters, including a target sampling volume and a maximum allowable flow rate;

[0022] The sampling parameters are sent to the PLC control unit, which automatically starts the water pump to allow water to flow through the filter to complete the enrichment of the two insects; the filter storage chamber is maintained at 0-4℃ throughout the process;

[0023] Monitor flow data in real time and automatically adjust the pump power when the instantaneous flow exceeds the maximum allowable flow;

[0024] When the accumulated flow reaches the preset flow, the water pump is automatically shut down and the solenoid valve is triggered to cut off the pipeline; a sampling log is generated, including sampling time, water temperature, flow curve and equipment status parameters.

[0025] In one embodiment, the method further comprises:

[0026] Automatically send sampling logs to the remote monitoring platform, and issue a maintenance alarm if it detects that the filter element clogging coefficient exceeds the preset value.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] In this embodiment, the fixed structure utilizes a waterproof and rust-resistant metal frame, adaptable to various operating environments, particularly humid or corrosive environments, effectively extending the system's service life. Furthermore, its detachable design allows the system to be easily mounted on a wall or sampling point bracket, facilitating both installation and construction, as well as subsequent system maintenance, relocation, or relocation. The sampling module's water pump, filter, and dedicated filter element for two-parasite mites are sequentially connected, creating an efficient sampling process. The water pump provides stable power, ensuring smooth entry of water samples into the sampling system. The filter pre-filters large impurities, protecting the subsequent dedicated filter element for two-parasite mites and extending its service life. The dedicated filter element for two-parasite mites has an effective filtration pore size of 1-5 microns, enabling precise capture of target microorganisms (two-parasite mites) in the water, ensuring accurate and effective sampling. A PLC control unit monitors the cumulative flow rate of the sampling module in real time via a flow meter and automatically shuts off the water pump power when the cumulative flow reaches a preset volume. This feature automates the sampling process, eliminating the potential errors and uncertainties associated with manual operation, ensuring the accuracy of each sample volume, and improving the reliability and comparability of the sampling data. The refrigeration module integrates a semiconductor refrigeration unit and temperature sensor, enabling real-time monitoring and maintaining the temperature of the dedicated filter cartridge storage chamber for the two insects between 0 and 4°C. Within this temperature range, the microorganisms (the two insects) in the water remain relatively stable, minimizing their growth, reproduction, and mortality, thereby ensuring sample quality and providing a reliable foundation for subsequent testing and analysis. The temperature sensor enables the refrigeration module to automatically adjust the operating state of the semiconductor refrigeration unit based on actual temperature conditions, achieving intelligent temperature control. This intelligent regulation not only ensures temperature stability but also effectively reduces energy consumption, improving the system's energy efficiency.

[0029] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the background technology, the drawings required for use in the embodiments of the present invention or the background technology will be described below.

[0031] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and, together with the specification, are used to explain the technical solutions of the present disclosure.

[0032] Figure 1 A schematic diagram of the structure of a PLC fully automated online sampling control system for water quality provided by an embodiment of the present invention;

[0033] Figure 2 for Figure 1 A schematic structural diagram of the middle refrigeration module 300;

[0034] Figure 3 for Figure 1 A schematic structural diagram of the submodules of the PLC control unit 100;

[0035] Figure 4 A flow chart of a PLC fully automated online sampling control method for water supply quality provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0037] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of a PLC fully automated online sampling control system for water quality provided by an embodiment of the present invention. Figure 1 As shown, the system includes:

[0039] PLC control unit 100, sampling module 200, refrigeration module 300 and fixed structure 400;

[0040] The fixed structure 400 is a waterproof and rust-proof metal frame that can be detachably fixed to a wall or a sampling point bracket;

[0041] The sampling module 200 comprises a water pump, a filter and two insect-specific filter elements connected in sequence; the effective filtration pore size of the filter element is 1-5 microns;

[0042] The PLC control unit 100 monitors the cumulative flow of the sampling module 200 in real time through a flow meter, and automatically cuts off the power supply of the water pump when the cumulative flow reaches a preset volume;

[0043] The refrigeration module 300 is integrated with a semiconductor refrigeration device and a temperature sensor to maintain the temperature of the two insect-specific filter storage bins at 0-4°C.

[0044] First, select an appropriate installation location based on actual sampling requirements, such as a wall or sampling point bracket. Secure the fixed structure 400, consisting of a waterproof and rust-proof metal frame, to the selected location using removable means (such as bolts or clips). This removable design facilitates subsequent maintenance, relocation, or replacement of the system. Install the sampling module 200, PLC control unit, and refrigeration module 300 on the fixed structure 400 according to the design requirements. Ensure that each module is securely installed to prevent vibration or shaking that may affect normal system operation.

[0045] Connect the water pump, filter, and two-parasite filter cartridge in sequence. Connect the pump's inlet to the water supply pipe, using the pump's suction to draw the water sample into the sampling system. Connect the pump's outlet to the filter's inlet, which removes large particles from the water sample and protects the two-parasite filter cartridge. Connect the filter's outlet to the inlet of the two-parasite filter cartridge, which has an effective filtration pore size of 1-5 microns and can accurately capture the target microorganisms in the water, namely Giardia lamblia and Cryptosporidium.

[0046] The PLC control unit 100 is connected to the water pump's power supply via a control signal line to control its start and stop. A flow meter, installed on the sampling module 200's piping, transmits flow rate data to the PLC control unit via a signal line. The two-worm filter cartridge is placed in the storage compartment of the refrigeration module 300, which provides a stable, low-temperature storage environment. A temperature sensor transmits temperature data within the storage compartment to the PLC control unit via a signal line. The PLC control unit 100 controls the start and stop of the semiconductor refrigeration unit via the control signal line. The overall water flow direction is from the pump outlet to the filter inlet, then to the filter outlet, and finally to the two-worm filter cartridge inlet.

[0047] After the sampling control system is activated, the water pump begins operating, drawing water samples from the water supply pipe into the sampling module 200. The water sample then passes through a filter and a dedicated filter element for the two insects. Large impurities in the water are removed by the filter, while the target microorganisms (the two insects) are captured by the dedicated filter element. Simultaneously, a flow meter monitors the cumulative flow rate in the sampling module 200 in real time and transmits this flow rate data to the PLC control unit 100. When the cumulative flow rate reaches a preset volume, the PLC control unit 100 receives a signal from the flow meter and automatically shuts off the power to the water pump, stopping sampling. This ensures the accuracy of each sample volume and improves the reliability and comparability of the sampled data. A temperature sensor monitors the temperature inside the storage chamber of the two insects filter element in real time and transmits this temperature data to the PLC control unit 100. When the temperature inside the storage chamber exceeds 4°C, the PLC control unit 100 activates the semiconductor refrigeration unit to lower the temperature. When the temperature falls below 0°C, the PLC control unit 100 deactivates the semiconductor refrigeration unit to prevent the temperature from dropping too low and affecting sample quality. This intelligent control maintains the storage chamber temperature between 0 and 4°C, ensuring sample quality.

[0048] See also Figure 2 In one embodiment, the refrigeration module 300 adopts a double-layer vacuum insulation structure, with a phase change energy storage material layer provided on the outer layer, which can maintain a low-temperature environment for more than 8 hours in the event of a power outage.

[0049] First, the inner and outer layers of the refrigeration module 300 are fabricated separately. The inner layer is constructed of a material with good thermal conductivity, such as stainless steel, to ensure that the cooling effect of the semiconductor refrigeration unit is effectively transferred to the storage chamber. The outer layer is constructed of a high-strength, thermally insulating material, such as glass fiber reinforced plastic. The inner and outer layers are assembled together and evacuated using a specialized process to form a double-layer vacuum insulation structure, minimizing heat conduction and convection. For the phase change energy storage material layer, a suitable phase change energy storage material (such as a eutectic salt) can be selected and encapsulated in a sealed container or sheet. The encapsulated phase change energy storage material is then evenly applied to the inner wall of the outer layer, ensuring a tight bond with the double-layer vacuum insulation structure. The fabricated refrigeration module 300 is integrated into the fully automated online sampling and control system for water quality using a PLC. The temperature sensor, semiconductor refrigeration unit, and PLC control unit are connected according to the previously described connections to ensure proper communication and coordinated operation. At the same time, the two insect-specific filter element storage compartments are placed in appropriate locations of the refrigeration module 300 to ensure that they are in a good low-temperature storage environment.

[0050] In actual use, unexpected power outages may occur. This embodiment utilizes a double-layer vacuum insulation structure and a phase-change energy storage material layer, enabling the refrigeration module 300 to maintain a low-temperature environment for over eight hours after a power outage. This provides a sufficient time buffer for water sample preservation. Even during extended power outages, the temperature within the dedicated filter cartridge for the two insects can be maintained between 0 and 4°C, effectively preventing the growth, reproduction, or death of microorganisms (the two insects) in the water due to elevated temperatures, thereby ensuring sample quality and the accuracy of test results. The double-layer vacuum insulation structure significantly reduces heat transfer, lowering the energy consumption of the semiconductor refrigeration device. The phase-change energy storage material layer absorbs and stores cold energy during the refrigeration process, releasing it during a power outage, further assisting in maintaining a low-temperature environment and reducing reliance on external energy sources. This design makes the refrigeration module 300 more energy-efficient during normal operation and reduces operating costs.

[0051] Furthermore, the stable low-temperature environment not only facilitates sample preservation but also protects equipment within the cold storage module 300 (such as semiconductor refrigeration devices and temperature sensors). This reduces damage to the equipment caused by temperature fluctuations, lowers equipment failure rates, extends equipment life, and reduces maintenance and replacement costs.

[0052] In one embodiment, the two-worm dedicated filter element is made of polycarbonate, has a porosity greater than 85%, and an effective filtration area greater than 200 cm².

[0053] When manufacturing polycarbonate filter elements, a specific molding process is used to create two-worm-specific filter elements. Common methods include phase inversion and stretching. Taking the phase inversion method as an example, polycarbonate is dissolved in a suitable solvent to form a uniform solution. The solution is then extruded through a specific mold or coated onto a support material. The solution is then placed in a coagulation bath to exchange the solvent and coagulant, thereby solidifying the polycarbonate to form a filter element with a porous structure. During the molding process, the porosity and pore size of the filter element are adjusted by controlling process parameters such as solution concentration, coagulation bath composition, temperature, and time to ensure a porosity greater than 85% and an effective filtration pore size of 1-5 microns.

[0054] Integrate the manufactured two-worm filter cartridge into the sampling module 200. Connect the filter cartridge's water inlet to the filter's water outlet according to the sampling module 200's connection method, ensuring a tight connection and a good seal to prevent water sample leakage. Also, install the filter cartridge in the proper position to ensure smooth sampling.

[0055] The porosity of the two-parasite filter element exceeds 85%, meaning it contains numerous pores, providing more channels for the water sample to flow. During sampling, the water sample can pass through the filter element more smoothly, reducing flow resistance and improving sampling efficiency. Furthermore, the high porosity increases the contact area between the filter element and the water sample, providing more opportunities for the target microorganisms (the two-parasite) to be captured by the filter element, thereby improving filtration efficiency and accuracy. The effective filtration area exceeds 200 cm², providing more space for the filtration process. This larger filtration area allows more water sample to be processed per unit time, further increasing sampling speed. Furthermore, the large filtration area extends the filter element's lifespan, as the pollutant load per unit area is relatively low for the same sampling volume, reducing the risk of filter clogging and extending the filter replacement cycle.

[0056] In addition, polycarbonate has excellent chemical stability and mechanical properties. It is resistant to most chemicals and can maintain stable performance in different water quality environments. It will not corrode or dissolve due to the chemical components in the water sample, ensuring the reliability and durability of the filter element.

[0057] In one embodiment, the PLC control unit 100 is integrated with a wireless communication module for remote parameter setting, status monitoring and abnormality alarm functions.

[0058] Connect the selected wireless communication module to the PLC control unit via an appropriate interface (such as a serial port or Ethernet port), ensuring a secure connection and stable signal transmission. Also, equip the wireless communication module with the necessary antenna to enhance signal strength and coverage. This allows operators to set and adjust system operating parameters remotely without having to be physically present on-site, significantly saving time and labor costs.

[0059] When an abnormality occurs in the system, an alarm message is promptly sent to a remote terminal, allowing relevant personnel to quickly learn of the fault and respond. This helps minimize the impact of the fault on the system and reduce losses. For example, when the temperature of the refrigeration module 300 exceeds the normal range, the system will immediately issue an alarm, reminding the operator to promptly check the refrigeration equipment to prevent sample damage due to excessive temperatures. After a fault occurs, the operator can obtain detailed system operating data through the remote terminal for remote diagnosis and analysis, helping to quickly locate the cause of the fault, develop an effective repair plan, and shorten fault resolution time.

[0060] In one embodiment, the fixing structure 400 is equipped with a multi-directional adjustment bracket, allowing the sampling control system to be installed at an angle adjusted within a range of ±15° in the vertical direction.

[0061] First, fix the fixed structure 400 of the waterproof and rust-proof metal frame to the wall or sampling point bracket in a detachable manner (such as bolts or clips) according to the installation method described above. Install the multi-directional adjustment bracket to the fixed structure 400 to ensure a firm connection. Welding, bolt connection, etc. can be used, and the connection points must undergo strict strength testing to prevent loosening during use. Install the sampling module 200, PLC control unit 100, and refrigeration module 300 on the fixed structure 400 according to the design requirements to ensure that the connection between each module is correct and stable. According to the actual sampling needs and on-site environmental conditions, loosen the locking device of the multi-directional adjustment bracket and adjust the angle of the sampling control system in the vertical direction to achieve a suitable installation angle within the adjustment range of ±15°. After the adjustment is completed, tighten the locking device to ensure that the angle is fixed.

[0062] After completing the angle adjustment, conduct a comprehensive commissioning of the entire sampling control system and check the operation of each module to ensure that the system is working properly. At the same time, check the locking status of the multi-directional adjustment bracket to ensure that the angle does not change during system operation.

[0063] Preferably, at the actual water supply quality sampling site, the installation space and terrain conditions may vary. In some places, the walls or brackets are not completely vertical or horizontal. After being equipped with a multi-directional adjustment bracket, the sampling control system can adjust the angle according to the actual situation on site, thereby adapting to different installation environments and ensuring that the system can be smoothly installed and used. By adjusting the installation angle of the system, the sampling position and direction can be better selected. For example, at some sampling points where the water flow direction is irregular, by adjusting the angle, the sampling module 200 can more accurately collect representative water samples, thereby improving the accuracy and reliability of sampling.

[0064] Thus, a reasonable installation angle allows the sampling module 200 to better cope with the impact of water flow during the sampling process. By adjusting the angle, water flows into the sampling module 200 in a more appropriate manner, reducing the impact and wear on system components, thereby improving the performance stability and service life of the system. Furthermore, a suitable installation angle helps ensure the coordinated operation of various components, such as the sampling module 200, the PLC control unit, and the refrigeration module 300. For example, arranging the connecting pipe between the sampling module 200 and the refrigeration module 300 in a more reasonable position reduces pipe bends and resistance, ensuring that the water sample can flow smoothly into the refrigeration module 300, and improving the overall operating efficiency of the system.

[0065] In one embodiment, the refrigeration module 300 is further integrated with a temperature control enrichment module, which has a vacuum interlayer filter chamber, a built-in compressor refrigeration plate and a phase change material layer, and starts graded temperature control according to the temperature data of the sampled water quality.

[0066] Create a filter chamber with a vacuum interlayer. This layer effectively reduces heat transfer and provides excellent insulation. The filter chamber can be made of materials such as stainless steel to ensure its strength and corrosion resistance. Install a compressor refrigeration plate and a phase change material layer within the filter chamber. The compressor refrigeration plate, as the primary refrigeration component, is responsible for lowering the temperature within the filter chamber. The phase change material layer absorbs and stores cold energy during the cooling process, releasing it when needed to stabilize the temperature. Connect the temperature control enrichment module to the compressor refrigeration plate and temperature sensor to ensure that the module can accurately obtain temperature data and control the operation of the compressor refrigeration plate.

[0067] A temperature sensor is installed at a suitable location on the sampling module 200 to monitor the sampled water temperature in real time. The temperature sensor is connected to the temperature control and enrichment module via a signal cable, transmitting temperature data to the module. The module is integrated with a PLC control unit, allowing it to receive data from the module and control the system according to a pre-set program. Parameters for tiered temperature control, such as cooling intensity and operating time for different temperature ranges, can be set through programming.

[0068] During system operation, the temperature sensor collects real-time temperature data from the sampled water and transmits it to the temperature control and enrichment module. The module analyzes this temperature data to determine within which preset temperature range the current water temperature falls. Based on the analysis, the module initiates the corresponding tiered temperature control strategy. For example, when the sampled water temperature is high, the module controls the compressor cooling fins to operate at higher power to rapidly reduce the temperature within the filter chamber. When the temperature approaches the preset optimal range, the cooling power is reduced to maintain temperature stability. Simultaneously, the phase change material layer absorbs cold energy during the cooling process and releases it when the cooling power is reduced or stopped, further stabilizing the temperature.

[0069] This embodiment utilizes a graded temperature control function that automatically adjusts cooling intensity based on the actual temperature of the sampled water, ensuring that the temperature within the dedicated filter cartridge for the two parasites is consistently maintained within the optimal range of 0-4°C, enhancing the system's adaptability to varying water temperatures. Precise temperature control effectively minimizes the impact of temperature fluctuations on samples, ensuring a relatively stable environment for target microorganisms (the two parasites), reducing their growth, reproduction, and mortality, thereby improving sample preservation quality and providing more reliable samples for subsequent testing and analysis. The graded temperature control strategy adjusts cooling power based on actual temperature conditions, avoiding the drawback of traditional refrigeration methods that operate at maximum power in all conditions and achieving on-demand cooling. The vacuum-coated filter chamber and phase change material layer work together to effectively minimize the impact of external temperatures on the filter chamber temperature, reducing the magnitude of temperature fluctuations. Furthermore, this graded temperature control strategy ensures that the compressor refrigeration fins operate under optimal conditions, avoiding prolonged high-load operation, reducing equipment wear and failure, extending equipment life, and lowering maintenance costs.

[0070] See also Figure 3 In one embodiment, the PLC control unit 100 further integrates a dynamic adjustment module 101 for:

[0071] Establish a turbidity-flow mapping table to divide turbidity values into different levels and match them with corresponding flow rates;

[0072] Monitor the changes in turbidity level and use the preset acceleration gradient flow rate when the turbidity level changes.

[0073] Specifically, based on the collected turbidity data, turbidity values are classified into different levels. For example, turbidity values can be divided into three levels: low, medium, and high, with each level corresponding to a turbidity value range. The specific classification can be adjusted based on actual needs and experimental data. For each turbidity level, the experimental data is analyzed to determine the optimal sampling flow rate that matches it. This flow rate should ensure sampling efficiency while ensuring that the filtration efficiency of the two-worm filter element is not reduced due to excessive flow rates, nor that sampling time is wasted due to excessive flow rates. The turbidity levels and corresponding flow rates are recorded to form a turbidity-flow mapping table. The established turbidity-flow mapping table is stored in the dynamic adjustment module 101 of the PLC control unit. The turbidity sensor is connected to the PLC control unit 100, allowing the PLC control unit to obtain the turbidity value of the water sample in real time.

[0074] During system operation, the turbidity sensor monitors the turbidity value of the water sample in real time and transmits this data to the dynamic adjustment module 101 of the PLC control unit. Dynamic adjustment module 101 determines the turbidity level to which the current turbidity value belongs based on a preset turbidity classification standard. When a change in turbidity level is detected, dynamic adjustment module 101 gradually increases the flow rate using a preset acceleration. For example, if the turbidity value changes from low to medium, dynamic adjustment module 101 gradually increases the sampling flow rate at a preset acceleration until it reaches the flow rate corresponding to medium turbidity. This prevents sudden changes in flow rate from adversely affecting the sampling process and the filter element.

[0075] Furthermore, by establishing a turbidity-flow mapping table, the system can automatically adjust the sampling flow rate according to the actual turbidity value of the water sample, making the sampling process more adaptable to different water quality conditions. In water samples with higher turbidity, appropriately reducing the flow rate can ensure that the filter element has sufficient time to filter impurities and improve the filtration effect; in water samples with lower turbidity, increasing the flow rate can shorten the sampling time and improve sampling efficiency. The use of a preset acceleration gradient flow rate avoids the interference of sudden changes in flow rate on the sampling process. The steady change in flow rate can make the flow of water samples in the filter element more stable, reduce the problem of filter element blockage or uneven filtration caused by sudden changes in flow rate, and thus ensure the stability and accuracy of sampling quality.

[0076] Therefore, reasonable flow rate adjustment can reduce filter element wear. In the case of high turbidity, reducing the flow rate can prevent excessive impurities from quickly accumulating on the filter element and extend the service life of the filter element. In the case of low turbidity, increasing the flow rate can fully utilize the filter element's filtration capacity without causing excessive pressure on the filter element.

[0077] In one embodiment, the dynamic adjustment module 101 is further configured to generate a dynamic pressure difference compensation value according to the actual flow rate collected and the preset flow rate, so as to correct the water pump operating parameters during subsequent sampling.

[0078] ;

[0079] Where, is the dynamic pressure difference compensation value, The adjustment factor represents the adjustment intensity coefficient of the flow deviation, which is determined by experiments or system debugging and usually ranges from 0.5 to 2. Represent the actual flow rate and the set flow rate respectively. A larger response reacts strongly to flow deviations and corrects quickly but may cause oscillations. Smaller values indicate gradual corrections, making the system more stable but less responsive.

[0080] For example, the system sets the flow , actual measured flow , proportionality coefficient , substituted into the above formula to calculate ,because If the value is negative, it means that the flow rate is insufficient, so the PLC control unit 100 will increase the pump speed so that the subsequent sampling flow rate is adjusted to:

[0081] ;

[0082] Therefore, the flow rate after compensation approaches the target value, avoiding the decrease in sampling efficiency due to filter clogging.

[0083] See also Figure 4 In one embodiment, the present invention further provides a PLC fully automated online sampling control method for water quality, the method comprising:

[0084] S10, setting sampling parameters, wherein the sampling parameters include a target sampling volume and a maximum allowable flow rate;

[0085] Input the following parameters through the human-machine interface: target sampling volume, maximum allowable flow rate and sampling cycle interval; automatically load historical optimal parameters, such as when turbidity is detected When Down 20%.

[0086] S20, the sampling parameters are sent to the PLC control unit 100, which automatically starts the water pump to allow water to flow through the filter to complete the enrichment of the two insects; the filter storage chamber is maintained at 0-4°C throughout the process;

[0087] Start the semiconductor refrigeration system 1 hour before sampling, and control the filter compartment temperature to 2±1℃ through the temperature sensor closed loop. , inject pre-cooling refrigerant in advance to enhance cooling.

[0088] S30, monitor the flow data in real time and automatically adjust the water pump power when the instantaneous flow exceeds the maximum allowable flow;

[0089] After the PLC sends the start command, the solenoid valve opens first, and after a delay of 0.5s, the micro centrifugal pump is started. The water inlet passes through the stainless steel pre-filter to intercept impurities larger than 100μm, then enters the two insect enrichment filter membranes, and finally flows into the flow meter detection end. The filter element compartment adopts a double-layer vacuum insulation structure, and the interlayer is filled with aerogel insulation material. When the surface temperature of the filter membrane When the semiconductor refrigeration chip is started, the power consumption When the temperature When the filter is cooled, the heating resistor (500Ω) of the chamber is activated to prevent ice from damaging the filter membrane.

[0090] S40. When the accumulated flow reaches the preset flow, the water pump is automatically shut down and the solenoid valve is triggered to cut off the pipeline; a sampling log is generated, including the sampling time, water temperature, flow curve and equipment status parameters.

[0091] When the accumulated flow reaches the preset flow rate, the system enters fine mode. As the flow rate decreases, the pump stops and the solenoid valve closes after a 2-second delay to prevent siphoning. The storage format can be a CSV file containing the following fields: timestamp, water temperature (°C), instantaneous flow rate (L / min), accumulated volume (L), filter element temperature (°C), and alarm code. Flow curve recording: Flow data is saved every minute and a line graph is generated for embedding in PDF reports.

[0092] In one embodiment, the method further comprises:

[0093] Automatically send sampling logs to the remote monitoring platform, and issue a maintenance alarm if it detects that the filter element clogging coefficient exceeds the preset value.

[0094] By detecting the congestion coefficient, it is determined whether the congestion is light or heavy. When the congestion is light, a text message reminder can be sent. If it is heavy, it is necessary to trigger shutdown protection and push a work order. A maintenance work order is automatically generated and assigned to the nearest operation and maintenance personnel.

[0095] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

Claims

1. A PLC fully automated online sampling and control system for water quality, characterized in that: The system comprises: PLC control unit, sampling module, refrigeration module and fixed structure; The fixed structure adopts a waterproof and rust-proof metal frame, which can be detachably fixed to the wall or the sampling point bracket; The sampling module includes a water pump, a filter and two insect-specific filter elements connected in sequence; the effective filtration pore size of the filter element is 1-5 microns; The PLC control unit monitors the cumulative flow of the sampling module in real time through a flow meter, and automatically cuts off the power supply of the water pump when the cumulative flow reaches a preset volume; The refrigeration module is integrated with a semiconductor refrigeration device and a temperature sensor to maintain the temperature of the two insect-specific filter storage bin at 0-4°C.

2. The PLC fully automated online sampling and control system for water supply quality according to claim 1 is characterized in that: The refrigeration module adopts a double-layer vacuum insulation structure, and a phase change energy storage material layer is provided on the outer layer, which can maintain a low-temperature environment for more than 8 hours in the event of a power outage.

3. The PLC fully automated online sampling and control system for water supply quality according to claim 1 is characterized in that: The two-worm special filter element is made of polycarbonate, with a porosity greater than 85% and an effective filtration area greater than 200 cm².

4. The PLC fully automated online sampling and control system for water supply quality according to claim 1 is characterized in that: The PLC control unit is integrated with a wireless communication module for remote parameter setting, status monitoring and abnormal alarm functions.

5. The PLC fully automated online sampling and control system for water supply quality according to claim 1 is characterized in that: The fixed structure is equipped with a multi-directional adjustment bracket, allowing the sampling control system to adjust the installation angle within the range of ±15° in the vertical direction.

6. The PLC fully automated online sampling and control system for water supply quality according to claim 1 is characterized in that: The refrigeration module also integrates a temperature control and enrichment module, a filter chamber with a vacuum interlayer, a built-in compressor refrigeration plate and a phase change material layer, and starts graded temperature control according to the temperature data of the sampled water quality.

7. The PLC fully automated online sampling and control system for water supply quality according to claim 1 is characterized in that: The PLC control unit also integrates a dynamic adjustment module for: Establish a turbidity-flow mapping table to divide turbidity values into different levels and match them with corresponding flow rates; Monitor the changes in turbidity level and use the preset acceleration gradient flow rate when the turbidity level changes.

8. The PLC fully automated online sampling and control system for water supply quality according to claim 7 is characterized in that: The dynamic adjustment module is further used to generate a dynamic pressure difference compensation value according to the actual flow rate actually collected and the preset flow rate, so as to correct the water pump operating parameters during subsequent sampling.

9. A PLC fully automated online sampling control method for water supply quality, applied to the PLC fully automated online sampling control system for water supply quality according to any one of claims 1 to 8, characterized in that: The method comprises: Setting sampling parameters, including a target sampling volume and a maximum allowable flow rate; The sampling parameters are sent to the PLC control unit, which automatically starts the water pump to allow water to flow through the filter to complete the enrichment of the two insects; the filter storage chamber is maintained at 0-4℃ throughout the process; Monitor flow data in real time and automatically adjust the pump power when the instantaneous flow exceeds the maximum allowable flow; When the accumulated flow reaches the preset flow, the water pump is automatically shut down and the solenoid valve is triggered to cut off the pipeline; a sampling log is generated, including sampling time, water temperature, flow curve and equipment status parameters.

10. The PLC fully automated online sampling control method for water supply quality according to claim 9, characterized in that: The method further comprises: Automatically send sampling logs to the remote monitoring platform, and issue a maintenance alarm if it detects that the filter element clogging coefficient exceeds the preset value.

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