Method and device for controlling parameters of multistage countercurrent water washing of latex products

Abstract

This application relates to the field of latex product manufacturing technology, and particularly to a method and apparatus for controlling parameters of multi-stage countercurrent washing of latex products. The method includes: acquiring the operating status of the washing system and the water quality parameters of each stage of the washing tank; acquiring the washing load parameters of the multi-stage countercurrent washing device when the operating status indicates that the i-th stage washing tank is in washing operation; determining a supplementary trigger threshold and a water supply capacity threshold based on the washing load parameters; and controlling the increase of the supplementary water intake of the i-th stage washing tank when the i-th stage washing tank is in washing operation, the effective washing capacity index of the i-th stage washing tank is less than or equal to the supplementary trigger threshold, and the effective washing capacity index of the (i+1)-th stage washing tank is greater than or equal to the water supply capacity threshold. The method provided by this application can solve the problem of low washing quality caused by using conductivity thresholds as trigger conditions to control the supplementary water intake of each stage of the washing tank.

Description

Technical Field

[0001] This application belongs to the field of latex product manufacturing technology, and in particular relates to a method and apparatus for controlling parameters of multi-stage countercurrent water washing of latex products. Background Technology

[0002] During the impregnation molding process of latex products (such as natural latex gloves and latex bedding), various compounding agents contained in the latex raw materials, such as sulfur vulcanizing agents, thiazole or thiuram accelerators, zinc oxide activators, and amine antioxidants, remain in large quantities on the surface and shallow matrix of the product after molding. If these residues are not effectively removed, they not only affect the physical properties and appearance of the product but may also cause contact allergic reactions in users. Therefore, a multi-stage washing process can reduce the residue content to below safe standards. Multi-stage countercurrent washing is a washing process used in latex product manufacturing. This process typically involves 3 to 5 washing tanks, arranged sequentially along the conveying direction of the latex products. The latex products enter from the first-stage washing tank (the inlet end, with the highest contaminant load), undergo progressive washing through each stage of the washing tanks, and finally exit from the last-stage washing tank (the outlet end, with the cleanest water).

[0003] In existing technologies, the control of the water supply to each stage of the washing tank is based on a conductivity threshold as the trigger condition. This threshold can be calibrated based on specific latex product formulations and production line speeds. Under calibrated conditions, the typical rate of change of the washing tank's conductivity determines the time it takes for the conductivity to rise from its initial level to the threshold, as well as the absolute state of the water quality when the threshold is reached. When the conductivity of a certain stage of the washing tank rises to this fixed threshold, the water supply pipeline for that stage is opened to increase the water supply volume. However, the washing load between different batches of latex products varies significantly due to factors such as formulation differences, product structure differences, vulcanization process fluctuations, and production line speed changes. Different formulations of latex products contain varying types and amounts of compounding agents. For example, the extractable protein precursor content in the formulation of natural latex thin inspection gloves is approximately 150 to 300 micrograms per gram of dry rubber, while in the formulation of natural latex high-protein bedding, this content can reach 500 to 1200 micrograms per gram of dry rubber, a difference of several times. When the actual washing load exceeds the calibration conditions, the amount of residual chemicals released from latex products into the washing water per unit time increases, the rate of increase in conductivity of each washing tank accelerates, and when the conductivity reaches a fixed threshold, the decline in water quality is greater than the corresponding decline under calibration conditions. The margin between water quality and washing quality requirements narrows, and by the time the conductivity exceeds the fixed threshold, the water quality has severely deteriorated, replenishment is delayed, and thus, the washing quality is poor. When the actual washing load is lower than the calibration conditions, the amount of residual chemicals released into the washing water per unit time decreases, the rate of increase in conductivity of each washing tank slows down, and the conductivity remains below the fixed threshold for a long time. The replenishment trigger condition is not met for a long time, the replenishment action is not initiated, and the washing water in each washing tank is continuously recycled, which also leads to poor washing quality. Summary of the Invention

[0004] This application provides a method and apparatus for controlling parameters of multi-stage countercurrent washing of latex products, which can solve the problem in the prior art where the control of the water supply to each stage of the washing tank is based on the conductivity threshold as the trigger condition, resulting in low washing quality.

[0005] In a first aspect, embodiments of this application provide a method for controlling parameters of multi-stage countercurrent washing of latex products, applied to a multi-stage countercurrent washing device. The multi-stage countercurrent washing device includes at least three washing tanks arranged sequentially along the conveying direction of the latex products. Washing water flows sequentially through each washing tank in a direction opposite to the conveying direction of the latex products. Each washing tank is provided with an independent replenishment water pipe connected to a fresh water supply main. The method includes: The operating status of the washing system and the water quality parameters of each washing tank are obtained. The operating status is used to indicate the working status of each washing tank. The water quality parameters include at least the conductivity of the washing water in each washing tank. When the operating status indicates that the i-th stage washing tank is in the washing working state, the washing load parameters of the multi-stage countercurrent washing device are obtained; where i is a positive integer greater than or equal to 1 and less than the total number of stages of the washing tank, and the washing load parameters are calculated based on the long-term sliding average conductivity of the inlet washing tank of the multi-stage countercurrent washing device after temperature compensation, the production line speed, and the washing difficulty coefficient of the current batch. Based on the washing load parameters, the supplementary trigger threshold of the i-th level washing tank and the water supply capacity threshold of the (i+1)-th level washing tank are determined; wherein, the supplementary trigger threshold increases with the increase of the washing load parameters, and the water supply capacity threshold decreases with the increase of the washing load parameters. When the i-th level washing tank is in the washing operation state, the effective washing capacity index of the i-th level washing tank is less than or equal to the supplementary trigger threshold, and the effective washing capacity index of the (i+1)-th level washing tank is greater than or equal to the water supply capacity threshold, the supplementary water supply volume of the i-th level washing tank through the supplementary water supply pipeline is controlled to increase.

[0006] The technical solutions described in this application embodiment have at least the following technical effects: The multi-stage countercurrent washing parameter control method for latex products provided in this application calculates washing load parameters based on the long-term sliding average conductivity of the inlet washing tank after temperature compensation, the production line speed, and the washing difficulty coefficient of the current batch. This ensures that the washing load parameters reflect the actual load status of the current batch. The replenishment trigger threshold for the i-th stage washing tank and the water supply capacity threshold for the (i+1)-th stage washing tank are determined based on the washing load parameters. The replenishment trigger threshold increases with the increase of the washing load parameters, while the water supply capacity threshold decreases, thus linking the determination of the replenishment trigger threshold and the water supply capacity threshold to the current washing load. When the washing load parameters are large, increasing the replenishment trigger threshold allows the effective washing capacity index of the i-th stage washing tank to meet the condition of increasing the replenishment water volume while it is still at a relatively high level. This advances the replenishment initiation time, reducing the possibility of water quality deterioration due to delayed replenishment. Conversely, decreasing the water supply capacity threshold lowers the requirement threshold for the effective washing capacity index of the (i+1)-th stage washing tank, improving the timeliness of replenishment. When the washing load parameters are low, reducing the replenishment trigger threshold allows the effective washing capacity index of the i-th stage washing tank to meet the condition of increasing the replenishment water volume at a relatively low level. This facilitates timely activation of the replenishment action under low load conditions, maintaining the water quality renewal of the washing water in each stage of the washing tank. By using the effective washing capacity index of the (i+1)-th stage washing tank being greater than or equal to the water supply capacity threshold as one of the conditions for increasing the replenishment water volume of the i-th stage washing tank via the replenishment water inlet pipeline, the upstream water quality status participates in the replenishment triggering judgment process. This is beneficial for coordinating the allocation of replenishment resources according to the actual needs of the water quality gradient when the total water supply capacity is limited, thereby contributing to improving the washing quality.

[0007] Secondly, embodiments of this application provide a multi-stage countercurrent washing parameter control system for latex products, applied to a multi-stage countercurrent washing device, for implementing the multi-stage countercurrent washing parameter control method for latex products as described in any of the first aspects above. The multi-stage countercurrent washing parameter control system for latex products includes: The detection unit is used to acquire the operating status of the washing system and the water quality status parameters of each washing tank. The operating status is used to indicate the working status of each washing tank, and the water quality status parameters include at least the conductivity of the washing water in each washing tank. The acquisition unit is used to acquire the washing load parameters of the multi-stage countercurrent washing device when the operating status indicates that the i-th stage washing tank is in the washing working state; wherein, i is a positive integer greater than or equal to 1 and less than the total number of stages of the washing tank, and the washing load parameters are calculated based on the long-term sliding average conductivity of the inlet washing tank of the multi-stage countercurrent washing device after temperature compensation, the production line speed, and the washing difficulty coefficient of the current batch; The calculation unit is used to determine the supplementary trigger threshold of the i-th level water washing tank and the water supply capacity threshold of the (i+1)-th level water washing tank according to the water washing load parameters; wherein, the supplementary trigger threshold increases with the increase of the water washing load parameters, and the water supply capacity threshold decreases with the increase of the water washing load parameters. The control unit is configured to increase the amount of water supplied to the i-th stage washing tank via the replenishment water inlet pipe when the i-th stage washing tank is in the washing operation state, the effective washing capacity index of the i-th stage washing tank is less than or equal to the replenishment trigger threshold, and the effective washing capacity index of the (i+1)-th stage washing tank is greater than or equal to the water supply capacity threshold.

[0008] Thirdly, embodiments of this application provide a multi-stage countercurrent washing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the multi-stage countercurrent washing parameter control method for latex products as described in any of the first aspects above.

[0009] It is understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic flowchart of a method for controlling parameters of multi-stage countercurrent washing of latex products according to an embodiment of this application; Figure 2 This is a schematic diagram of the water washing tank and the direction of the washing water flow provided in one embodiment of this application; Figure 3 This is a schematic diagram of controlling the start of fresh water replenishment in a multi-stage countercurrent washing parameter control method for latex products provided in an embodiment of this application; Figure 4 This is a schematic diagram illustrating the determination of washing load parameters in a multi-stage countercurrent washing parameter control method for latex products provided in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of the multi-stage countercurrent water washing parameter control system for latex products provided in the embodiments of this application; Figure 6 This is a schematic diagram of the control device of the multi-stage countercurrent water washing device provided in the embodiments of this application. Detailed Implementation

[0012] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0013] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0014] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0015] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if the described condition or event is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once the described condition or event is detected," or "in response to the detection of the described condition or event."

[0016] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0017] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0018] In related technologies, the control of the water supply to each stage of the washing tank is based on conductivity thresholds as triggering conditions. However, the washing load of different batches of latex products varies significantly due to factors such as formulation differences, product structure differences, vulcanization process fluctuations, and production line speed changes. Different formulations of latex products contain different types and amounts of compounding agents. When the actual washing load exceeds the calibration conditions, the amount of residual chemicals released from the latex products into the washing water per unit time increases, and the rate of increase in conductivity of each stage of the washing tank accelerates. By the time the conductivity exceeds the fixed threshold, the water quality has severely deteriorated, replenishment is delayed, and thus, the washing quality is poor. When the actual washing load is lower than the calibration conditions, the amount of residual chemicals released into the washing water per unit time decreases, the rate of increase in conductivity of each stage of the washing tank slows down, and the conductivity remains below the fixed threshold for a long time. The replenishment triggering condition is not met for an extended period, and the replenishment action is not initiated, also leading to poor washing quality.

[0019] To address the aforementioned issues, this application provides a method and apparatus for controlling parameters of multi-stage countercurrent washing of latex products.

[0020] In this method, the washing load parameters are calculated based on the long-term sliding average conductivity of the inlet washing tank after temperature compensation, the production line speed, and the washing difficulty coefficient of the current batch. This ensures that the washing load parameters reflect the actual load condition of the current batch. The replenishment trigger threshold for the i-th level washing tank and the water supply capacity threshold for the (i+1)-th level washing tank are determined based on the washing load parameters. The replenishment trigger threshold increases with the increase of the washing load parameters, while the water supply capacity threshold decreases, thus linking the determination of these thresholds to the current washing load. When the washing load parameters are large, increasing the replenishment trigger threshold allows the effective washing capacity index of the i-th level washing tank to meet the condition of controlling the increase in replenishment water volume while it is still at a relatively high level. This advances the replenishment initiation time, reducing the possibility of water quality deterioration due to delayed replenishment. Conversely, decreasing the water supply capacity threshold lowers the requirement threshold for the effective washing capacity index of the (i+1)-th level washing tank, improving the timeliness of replenishment. When the washing load parameters are low, reducing the replenishment trigger threshold allows the effective washing capacity index of the i-th stage washing tank to meet the condition of increasing the replenishment water volume at a relatively low level. This facilitates timely activation of the replenishment action under low load conditions, maintaining the water quality renewal of the washing water in each stage of the washing tank. By using the effective washing capacity index of the (i+1)-th stage washing tank being greater than or equal to the water supply capacity threshold as one of the conditions for increasing the replenishment water volume of the i-th stage washing tank via the replenishment water inlet pipeline, the upstream water quality status participates in the replenishment triggering judgment process. This is beneficial for coordinating the allocation of replenishment resources according to the actual needs of the water quality gradient when the total water supply capacity is limited, thereby contributing to improving the washing quality. The effects of the above-mentioned replenishment control mechanism can be understood from the following two levels: At the process level, the dynamic threshold matches the replenishment timing with the actual washing load, and the steady-state conductivity of each washing tank is controlled at a lower level; At the result level, a lower steady-state conductivity means a lower concentration of residual chemicals in the washing water, a greater washing driving force (greater concentration gradient), thereby washing out more residual chemicals from latex products, reducing the residual protein content of the final product, and improving the washing quality.

[0021] The multi-stage countercurrent washing parameter control method for latex products provided in this application embodiment can be applied to a multi-stage countercurrent washing device. In this case, the multi-stage countercurrent washing device is the executing entity of the multi-stage countercurrent washing parameter control method for latex products provided in this application embodiment. This application embodiment does not impose any restrictions on the specific type of multi-stage countercurrent washing device.

[0022] For example, a multi-stage counter-current washing device may include N-stage washing tanks (N≥3) arranged sequentially along the conveying direction of latex products, conductivity sensors, electric proportional control valves, and a control device. The control device is electrically connected to the conductivity sensors and the electric proportional control valves. The conductivity sensors are installed 20 to 30 cm below the liquid level in the middle of each stage of the washing tank. The electric proportional control valves are installed on the replenishment water supply pipelines. One end of each replenishment water supply pipeline connects to the middle or bottom of the side of each stage of the washing tank, and the other end connects to the fresh water supply main pipe. The fresh water supply main pipe draws water from a fresh water storage tank via a booster pump; the main pipe's water supply capacity is determined by the booster pump's power and the pipe diameter. The control device is connected to the conductivity sensors at each stage via analog signal lines to collect data. The control device is also connected to the electric proportional control valves at each stage via analog signal lines or a fieldbus to output opening control signals to the electric proportional control valves based on the collected data, thereby controlling the replenishment water volume of the replenishment water supply pipelines.

[0023] This embodiment uses a four-stage washing tank as an example. The first-stage washing tank is located at the inlet; the second and third-stage washing tanks are arranged sequentially; and the fourth-stage washing tank is located at the outlet. Fresh water is added from the outlet of the fourth-stage washing tank via bottom injection, flows through the fourth stage and then through an overflow weir into the third stage, overflows from the third stage to the second stage, and finally overflows from the second stage to the first stage, exiting as wastewater from the inlet of the first stage. Figure 2 As shown. An overflow weir or connecting pipe is provided between each two adjacent stages, allowing washing water to flow from the higher-numbered stage (outlet end) to the lower-numbered stage (inlet end) under the action of gravity or water level difference, while preventing latex products from flowing back from the lower-numbered stage.

[0024] For example, the control device can be a microcontroller, programmable logic controller (PLC), industrial computer, embedded industrial controller, industrial edge computing gateway, industrial touch screen all-in-one machine, laptop computer, ultra-mobile personal computer (UMPC), netbook, desktop computer, computing device or computer connected to a wireless modem, laptop computer, handheld communication device, handheld computing device, etc.

[0025] To better understand the multi-stage countercurrent washing parameter control method for latex products provided in the embodiments of this application, the specific implementation process of the multi-stage countercurrent washing parameter control method for latex products provided in the embodiments of this application will be described by way of example below.

[0026] Figure 1 This paper presents a schematic flowchart of a method for controlling parameters of multi-stage countercurrent washing of latex products according to an embodiment of this application. The method includes: S100: Obtain the operating status of the washing system and the water quality parameters of each washing tank. The operating status is used to indicate the working status of each washing tank. The water quality parameters include at least the conductivity of the washing water in each washing tank.

[0027] It is understandable that the operating status of the washing system can refer to the current working state of each level of the washing tank, including but not limited to the washing working state, the static state, and the drainage state. The operating status can be obtained through the operating status signal of the main control PLC of the production line. Water quality parameters can be measurable physical quantities reflecting the water quality of the washing water in each level of the washing tank, including at least the conductivity of the washing water in each level of the washing tank, and may also include auxiliary parameters such as the temperature and turbidity of the washing water.

[0028] For example, the control device can preset a sampling period to collect the raw readings kt of the conductivity sensor and Ti of the temperature sensor for each stage of the washing tank, where i = 1, 2, ..., N, and N is the total number of stages of the washing tank. Each level of data is timestamped to ensure that conductivity and temperature data at the same moment are paired for use. The preset sampling period can be set according to the system's data processing capabilities. For example, in this embodiment, the preset sampling period is 2 seconds, meaning that conductivity and temperature data for each stage of the washing tank are collected every 2 seconds.

[0029] Because conductivity measurements are significantly affected by water temperature, and the water temperatures in different washing tanks may vary, it is necessary to correct the original conductivity readings at each level to the conductivity values ​​at the standard temperature (i.e., temperature compensation processing) to eliminate the interference of temperature differences on water quality assessment. Temperature compensation processing can be a process of using temperature data collected by temperature sensors to uniformly correct the conductivity measured at different temperatures to the conductivity values ​​at the standard temperature using a temperature compensation formula.

[0030] For example, the temperature compensation formula is: k1i(t) = k2i(t) ÷ [1 + d × (Ti(t) - 25)]. Where k1i(t) is the conductivity of the i-th stage washing tank after temperature compensation at time t; k2i(t) is the original measured conductivity reading of the i-th stage washing tank at time t; Ti(t) is the measured water temperature of the i-th stage washing tank at time t; and d is the temperature compensation coefficient, the value of which depends on the chemical composition of the washing water; for example, d can be 0.025 / °C.

[0031] For example, the method for determining the temperature compensation coefficient d can be as follows: take at least 5 samples of the washing water used in the target washing system (i.e., washing water containing a known concentration of compounding agent residue), and measure its conductivity at different temperatures T (e.g., 20°C, 25°C, 30°C, 35°C, 40°C) using a calibrated conductivity meter. Using the conductivity at 25°C as a reference, fit the conductivity-temperature relationship curve k(T)=k(25)×[1+d×(T-25)], and the slope obtained by fitting is d.

[0032] The conductivity data after temperature compensation is smoothed using a short-time moving average to obtain smoothed conductivity data. For example, conductivity data for each level of the washing tank can be collected every 2 seconds. The short-time moving average involves taking all 30 samples from the most recent 60 seconds, performing temperature compensation on all 30 samples, summing these 30 values, and dividing by 30 to obtain an average value. Every 2 seconds, the oldest sample value is discarded, and the most recently collected sample value is added, and the average value is recalculated. This is done to eliminate momentary interference. In actual production, when air bubbles pass by the sensor or latex products pass near the sensor, the conductivity may experience short-term abnormal fluctuations. A single sample value may be too high or too low, but after averaging over 30 points, these momentary fluctuations are significantly reduced, and the resulting average value stably reflects the true water quality level of the washing tank at that moment. The short-time moving average is performed on all levels of the washing tank. The short-time moving average has two uses: first, it is used directly to calculate the effective washing capacity index of each level of the washing tank; second, it is used as input data for the long-time moving average, but only for level 1.

[0033] The short-time smoothed conductivity data of the inlet washing tank is processed using a long-term moving average to obtain the long-term moving average conductivity of the inlet washing tank. Specifically, this can be done by averaging the first-stage washing tank over a longer time span, based on the short-time moving average. For example, 300 short-time moving averages from the most recent period (which can be set according to the processing capacity of the multi-stage countercurrent washing device, for example, 10 minutes) can be taken, and these 300 values ​​can be summed and divided by 300 to obtain the long-term average. This is also updated every 2 seconds. The long-term moving average is only performed on the first-stage washing tank, and the result is specifically used to calculate the washing load parameters.

[0034] It's important to note that a longer-term average is needed on top of the short-term moving average because the replenishment operation itself introduces interference. When fresh water is injected into the first-stage washing tank, the conductivity within the tank decreases due to dilution. Washing tank volumes typically range from 500 to 2000 liters, with replenishment flow rates between 10 and 30 liters per minute. It takes 3 to 8 minutes for the fresh water to fully mix with the existing washing water before the conductivity sensor can reflect a stable, diluted value. If only the short-term moving average is considered, the temporary decrease in conductivity caused by the replenishment operation might be misinterpreted by the system as a reduction in the washing load, leading to premature cessation of replenishment. This results in the conductivity rising again, triggering another replenishment and creating a control oscillation of repeated start-stop cycles.

[0035] In this embodiment, a 10-minute long-term window is used to incorporate the short-term decrease in conductivity caused by replenishment operations into the mean calculation. This makes the long-term mean closer to the baseline load level reflecting the current batch of products and the current production speed—that is, the typical conductivity level of the first-stage washing tank when the washing system reaches a quasi-steady state—rather than the transient value after a replenishment operation. Using this more stable baseline value to calculate the washing load parameters avoids the control oscillation problem of prematurely stopping replenishment due to the misjudgment of conductivity decrease caused by replenishment operations as a load reduction.

[0036] S200: When the operating status indicates that the i-th stage washing tank is in the washing operation state, the washing load parameters of the multi-stage countercurrent washing device are obtained. Here, i is a positive integer greater than or equal to 1 and less than the total number of stages of the washing tank. The washing load parameters are calculated based on the long-term sliding average conductivity of the inlet washing tank of the multi-stage countercurrent washing device after temperature compensation, the production line speed, and the washing difficulty coefficient of the current batch.

[0037] It is understandable that the Wash Load Parameter (WLP) is used to characterize the overall contaminant load level exerted on the washing system by the current batch of latex products. The Wash Load Parameter (WLP) is a parameter for the entire multi-stage countercurrent washing unit, and its value is shared by all stages of the washing tank because all stages are dealing with the same batch of latex products and the same production line speed.

[0038] For example, the formula for calculating the washing load parameter WLP(t) is: WLP(t) = c1 × [v(t) ÷ v] × {[k_length - k_0] ÷ [k_allowable - k_0]}. Where c1 is the washing difficulty coefficient of the current batch; v(t) is the current production line speed; v is the reference production line speed (which can be determined based on commonly used production speeds during system debugging); k_length is the long-term sliding average of the conductivity of the first-stage washing tank; k_0 is the reference conductivity of fresh water (which can be measured and input by the operator at the fresh water sampling port during system debugging; in this embodiment, k_0 = 100 μS / cm); k_allowable is the maximum allowable conductivity of the first-stage washing tank (which can be determined by consulting industry rules; in this embodiment, k_allowable = 2000 μS / cm). [k_length - k_0] ÷ [k_allowable - k_0] reflects the current normalized contamination level of the first-stage washing tank.

[0039] Specifically, the production line speed can be the conveying speed of latex products in the washing system (related to the number of molds and the transmission speed). The production line speed can be obtained in the following ways: the control device establishes a communication connection with the main control PLC of the production line via industrial Ethernet or fieldbus (such as the Modbus TCP protocol) and periodically reads the production line speed parameters stored in the main control PLC. Alternatively, the control device obtains pulse signals through a rotary encoder installed on the drive shaft of the conveyor belt and calculates the production line speed based on the pulse frequency and the mechanical parameters of the conveyor belt.

[0040] The reference production line speed v can be determined as follows: during the system commissioning phase, the average operating speed of the production line served by the washing device over the past 30 consecutive normal production days is statistically analyzed, and this average value is taken as the reference production line speed v; or, the operator inputs the speed on the human-machine interface of the control device according to the design rated speed of the production line.

[0041] The batch coefficient c1 is a dimensionless coefficient characterizing the inherent wash load of the current batch of latex products, determined by factors such as product formulation, product structure, and vulcanization process. At the start of each batch of production, the operator can input the product type code for the current batch through the human-machine interface (touchscreen) of the control device. The system automatically queries and loads the c1 value based on the pre-stored product type-c1 correspondence table. If the operator inputs a custom c1 value based on laboratory pre-inspection results, that custom value will be used preferentially.

[0042] It is understandable that the determination of c1 may include: determining the initial wash load of the new formula through laboratory washing tests before producing the first batch of products (such as measuring the conductivity increment of a standardized sample under standard washing conditions), and determining the c1 value accordingly.

[0043] The product type-c1 correspondence table includes multiple product types and multiple c1 values, with a mapping relationship between product types and c1 values. c1 can be a value determined through laboratory washing tests before the first batch of products of a new formula is produced. For example, the product type-c1 correspondence table is as follows: Natural latex thin examination gloves (thickness 0.08-0.12mm), c1=0.6 to 0.8; Natural latex medium-thick household gloves (thickness 0.15-0.25mm), c1=0.8 to 1.0; Natural latex thick industrial gloves (thickness 0.30-0.40mm), c1=1.2 to 1.5; Natural latex high-protein bedding (mattresses, pillows), c1=1.5 to 2.0; Nitrile synthetic latex gloves, c1=0.4 to 0.6.

[0044] In one possible implementation, the method for selecting a specific value for c1 within the aforementioned range can be as follows: Taking thin natural latex inspection gloves as an example, the value of c1 ranges from 0.6 to 0.8, corresponding to a product thickness range of 0.08 mm to 0.12 mm. Operators can determine the c1 value using linear interpolation based on the actual thickness of the current batch of products. For example, when the product thickness is 0.10 mm, c1 = (0.10 - 0.08) ÷ (0.12 - 0.08) × (0.8 - 0.6) + 0.6 = 0.7. For other product types, the same linear interpolation method is used, interpolating values ​​within the corresponding range using key specifications (such as thickness, areal density, etc.) as independent variables. If the operator inputs a custom c1 value based on laboratory pre-inspection results, the custom value will be used.

[0045] When the operating status indicates that the i-th stage washing tank is in the washing operation state, the obtained production line speed v(t), c1, and the long-term sliding average conductivity k of the inlet washing tank are substituted into the washing load parameter calculation formula to calculate the current washing load parameter WLP(t), such as... Figure 4 .

[0046] When calculating the washing load parameter WLP(t), if the calculated result WLP(t) < 0 (the average conductivity of the first-stage washing tank under extreme conditions is lower than the reference conductivity of fresh water over a long period of time), then let WLP(t) = 0, that is, take the lower limit of the washing load parameter as zero.

[0047] S300, based on the washing load parameters, determine the supplementary trigger threshold for the i-th level washing tank and the water supply capacity threshold for the (i+1)-th level washing tank. The supplementary trigger threshold increases with the increase of the washing load parameters, while the water supply capacity threshold decreases with the increase of the washing load parameters.

[0048] It can be understood that the replenishment trigger threshold E1i(t) is a water quality standard used to determine whether the i-th stage washing tank needs to be replenished with fresh water. When the effective washing capacity index of the i-th stage washing tank drops below the replenishment trigger threshold, it indicates that the water quality of the i-th stage has deteriorated to the point where replenishment is necessary. The water supply capacity threshold E2i+1(t) is a system-level coordination standard used to determine whether the (i+1)-th stage washing tank has sufficient washing capacity to support the replenishment of the i-th stage. When the effective washing capacity index of the (i+1)-th stage washing tank is not lower than the water supply capacity threshold, it indicates that the upstream water quality is sufficient, allowing fresh water to be allocated to the i-th stage for replenishment.

[0049] Specifically, the replenishment trigger threshold E1i(t) increases with the increase of the washing load parameter WLP(t). Its physical meaning is that when the washing load is large, the water quality deteriorates faster in the i-th stage washing tank (because more residual chemicals are released from latex products into the washing water per unit time), requiring earlier replenishment to prevent the water quality from deteriorating to an unqualified level before replenishment can be completed. The water supply capacity threshold E2i+1(t) decreases with the increase of the washing load parameter WLP(t). Its physical meaning is that under high load conditions, the i-th stage has a more urgent need for replenishment, and the water quality requirement threshold for the upstream stage (i+1 stage) should be appropriately lowered to avoid limiting the replenishment opportunity for the i-th stage due to excessively high upstream thresholds.

[0050] For example, the first critical washing index under the current washing load can be determined according to a pre-set lookup table, and the supplementary trigger threshold can be determined based on the first critical washing index and the safety margin value. Simultaneously, the water supply capacity threshold can be determined based on the basic water supply capacity threshold and the water supply source load sensitivity coefficient.

[0051] In one possible implementation, S300, based on the washing load parameters, determines the supplementary trigger threshold for the i-th level washing tank, including: S310, based on the correspondence between the washing load parameters of the i-th stage washing tank and the effective washing capacity index, determine the first critical washing index corresponding to the washing load parameters.

[0052] It can be understood that the first critical washing index Ec(i) can be the minimum effective washing capacity index of the i-th stage washing tank under the current washing load to meet the washing quality requirements (i.e., the residual protein content of the latex product after this stage of washing is exactly equal to the quality standard limit). The first critical washing index is obtained by looking up a pre-calibrated EWCI-target washing load correspondence table. The washing load parameter can be expressed by a specific washing load value, which is used to characterize the comprehensive contaminant load level imposed on the washing system by the current batch of latex products. Specifically, using the currently calculated washing load parameter WLP(t) as the independent variable, the EWCI value corresponding to the washing load parameter value equal to WLP(t) is found in the lookup table, which is the first critical washing index Ec(i).

[0053] For example, the calibration method for the EWCI-target wash load correspondence is as follows: Under different wash load conditions (by changing the product formulation, production line speed, and replenishment water volume to obtain different combinations of wash load values), in each group of experiments, the replenishment water volume of the i-th stage wash tank is gradually reduced until the conductivity of that stage reaches a steady state. Then, samples are taken to test the residual protein content of the latex products after that stage of washing (using the ASTM D5712 or EN455-3 standard method). When the residual protein content is exactly equal to the quality standard limit (which can be obtained by consulting industry rules or experimental manuals, for example, it can be 200 μg / dm²), the EWCI value of that stage at this time (i.e., the washing ability index of stage i at this time) is recorded as E_critical(i) under that wash load value. Multiple (wash load value, E_critical(i)) data points are obtained through multiple groups of experiments, and a correspondence curve is fitted or a lookup table is established. After obtaining the corresponding relationship curve or establishing the lookup table, you can traverse the corresponding relationship curve or lookup table to find the first critical washing index corresponding to the water washing load value in the corresponding relationship curve or lookup table that is the same as the target water washing load of the i-th level water washing tank.

[0054] For example, taking the first-stage washing tank in a four-stage washing system as an example, the EWCI-target washing load lookup table obtained through the above calibration method during the system commissioning phase is as follows: For the values ​​of the water washing load parameters not directly listed in the table, the corresponding Ecrit(1) values ​​are calculated between adjacent data points using a linear interpolation method. The lookup table calibration method for other water washing tanks is the same, but the specific values ​​vary depending on the maximum allowable conductivity of each level.

[0055] S320, determine the supplementary trigger threshold based on the first critical washing index.

[0056] It can be understood that the supplementary trigger threshold can be determined according to the first critical washing index and the safety margin value. The safety margin value Δi is a buffer value used to trigger replenishment in advance before the water quality deteriorates to the critical level, and provides a safety buffer space for the first critical washing index.

[0057] Specifically, the calculation formula of the supplementary trigger threshold may be E1i(t)=clip{Ecri(i)+Δi, Elow, Ehigh}. Wherein, Elow is the lower limit protection value of the supplementary trigger threshold, Ehigh is the upper limit protection value of the supplementary trigger threshold, and clip{x,a,b} is an amplitude limiting function: when x is less than a, it takes a; when x is greater than b, it takes b; otherwise, it takes x. The purpose of amplitude limiting protection is to prevent the threshold from exceeding the physically reasonable range under extreme working conditions.

[0058] Since the supplementary trigger threshold E1i(t)=clip{Ecri(i)+Δi, Elow, Ehigh} increases with the increase of the water washing load parameter WLP(t), under the high water washing load working condition, the value of E1i(t) is relatively high, so that the effective washing capacity index Eeff(i) of the i-th water washing tank meets the trigger condition of Eeff(i)≤E1i(t) before it drops to the fixed threshold level under the calibrated working condition.

[0059] In some embodiments, the determination method of Elow and Ehigh may be: determining the reasonable value range of the supplementary trigger threshold according to the design working condition range of the multi-stage countercurrent water washing device (including the supplementary trigger threshold requirements corresponding to the maximum and minimum water washing load parameter values). For example, Elow can be 0.3, and Ehigh can be 0.9. The determination method of Elow_base and Ehigh_base is similar. Among them, Elow_base is used to ensure that the upstream water quality still meets the minimum requirements even under the extreme high load working condition, and exemplarily takes 0.15; Ehigh_base is equal to Ebase, which is the minimum requirement for upstream water quality under low load working conditions.

[0060] Of course, in some other embodiments, Elow and Ehigh can be obtained by querying the specification of the multi-stage countercurrent water washing device.

[0061] The determination method of the safety margin value Δi may be: Δi=α×[Ecri(i)-Elow], wherein α is a margin coefficient (the value ranges from 0.05 to 0.15), and its value can be determined according to the strictness of product quality requirements. The stricter the quality requirement, the larger the value of α.

[0062] In a possible implementation, the water supply capacity threshold is determined according to the basic water supply capacity threshold and the water supply source load sensitivity coefficient.

[0063] The formula for calculating the water supply capacity threshold is: E2i+1(t) = clip{Ebase - βi × water washing load parameter WLP(t), Esmall, Elarge}. Where, Ebase is the base water supply capacity threshold (static parameter), representing the minimum requirement for upstream water quality under low load conditions, which can be determined during the system design phase. βi is the water supply source load sensitivity coefficient (positive value), representing the sensitivity of the water supply capacity threshold to changes in water washing load. Esmall is the lower limit protection value of the water supply capacity threshold (taken as 0.15), and Elarge is the upper limit protection value (equal to Ebase). clip{x,a,b} is the limiting function: when x is less than a, take a; when x is greater than b, take b; otherwise, take x.

[0064] In one possible implementation, the basic water supply capacity threshold Ebase can be determined as follows: Under low water washing load conditions (taking c1 as the minimum product type, the reference production line speed, and the condition where k length approaches k0), the replenishment water volume of the i+1 level water washing tank is gradually reduced until the residual protein content of the latex product after the i-th level water washing is exactly equal to the quality standard limit. The effective washing capacity index of the i+1 level water washing tank at this time is recorded, which is Ebase.

[0065] In one possible implementation, the water supply load sensitivity coefficient βi can be determined by measuring the effective washing capacity index Ex of the (i+1)th level when the i-th level washing quality just meets the standard under different washing load conditions (at least 3 groups, obtained by changing c1 or production line speed), and performing linear fitting with (WLP(t),Ex) as data points. The absolute value of the slope of the fitted line is βi.

[0066] S400, when the i-th level water washing tank is in the water washing working state, the effective washing capacity index of the i-th level water washing tank is less than or equal to the supplementary trigger threshold, and the effective washing capacity index of the i+1-th level water washing tank is greater than or equal to the water supply capacity threshold, the supplementary water supply volume of the i-th level water washing tank through the supplementary water supply pipe is increased.

[0067] It can be understood that the effective washing capacity index Eeffective(i) is used to characterize the current sufficiency of the washing capacity of the i-th level washing tank. The replenishment trigger condition includes three conditions that must be met simultaneously: Condition 1, the i-th level washing tank is in washing operation (confirmed by the operating status signal of the production line main control PLC); Condition 2, Eeffective(i) ≤ E1i(t) (the water quality of the i-th level has deteriorated to the point where replenishment is required); Condition 3, Eeffective(i+1) ≥ E2i+1(t) (the upstream water quality still meets the system-level coordination requirements). Replenishment is initiated when all three conditions are met simultaneously.

[0068] Condition 1 ensures that replenishment control is only performed during the washing process. Condition 2 ensures that replenishment is triggered only when the water quality in the i-th stage washing tank has indeed deteriorated to the point where replenishment is necessary. Condition 3 ensures that replenishment is only performed when the water supply stage (i+1 stage) has sufficient washing capacity, avoiding blind replenishment when the water quality in the water supply stage itself is also deteriorating, which could lead to an imbalance in resource allocation between stages. The physical significance of Condition 3 is that in a counter-current washing system, stage i+1 is located upstream of stage i (closer to the outlet), and its water quality directly determines the quality of the counter-current washing water flowing to stage i and the washing quality of the final product. When the water quality in stage i+1 is sufficient, it indicates that the upstream stage has ample washing capacity and can allocate fresh water to replenish stage i; when the water quality in stage i+1 has also deteriorated, it indicates that the upstream stage also needs replenishment. In this case, the limited fresh water should be prioritized for supplying stage i+1, which is closer to the outlet, to ensure the quality of the final product, rather than prioritizing replenishment to stage i.

[0069] Specifically, for each level (i=1,2,...,N-1), in each control cycle, it is determined whether the three conditions are simultaneously met. If all three conditions are met, the replenishment execution process begins; if any condition is not met, the replenishment operation is not performed, and the current state is maintained. Figure 3 As shown.

[0070] Taking a three-stage water washing system as an example, assuming the initial state is the same. When using fixed threshold control, under a sudden load increase, the conductivity of the first stage rises rapidly until it reaches the trigger threshold before replenishment begins. At this point, the water quality has already deteriorated significantly, and the amount of fresh water required for replenishment is large, potentially exceeding the system's instantaneous water supply capacity, resulting in poor control performance. However, with the dynamic threshold control proposed in this application, since the replenishment trigger threshold shifts forward as the load increases, the first stage may trigger replenishment in the early stages of conductivity increase, requiring a small replenishment flow rate that is easily met. Simultaneously, the water supply capacity threshold is lowered, allowing replenishment to the first stage when the water quality of the second stage is still acceptable, avoiding unnecessary waiting.

[0071] With this arrangement, when the water washing load parameter WLP is large, the supplementary trigger threshold E1i(t) increases as WLP increases (see the formula E1i(t)=clip{Ecritical(i)+Δi, Elower, Eupper}, wherein Ecritical(i) increases correspondingly as the water washing load increases). Due to the increase of E1i(t), when the effective washing capacity index Eeffective(i) of the i-th water washing tank has not yet dropped to a low level, the trigger condition of Eeffective(i)≤E1i(t) is already satisfied, and the start timing of supply is advanced. When WLP is small, E1i(t) decreases as WLP decreases, so that the supply action can still be started in time under low-load working conditions. By taking EWCI of the (i+1)-th stage ≥ water supply capacity threshold as the supply constraint, when the total water supply capacity is limited, fresh water is preferentially allocated to the more urgent stage. When the water quality of the (i+1)-th stage has also deteriorated (Eeffective(i+1)<E2i+1(t)), the system will suspend the supply to the i-th stage, and prioritize guaranteeing the water quality closer to the outlet end, so as to ensure the water washing quality of the final product.

[0072] It should be pointed out that the technical effect of the present application cannot be obtained by simply applying the existing dynamic threshold idea to a water washing system. Specifically: First, in the present application, the supplementary trigger threshold and the water supply capacity threshold change in opposite directions along with the water washing load parameter (the former increases while the latter decreases), and the two together form a coupling control strategy that performs more active supply but is more tolerant to upstream water quality under high load. This coupling control strategy produces a synergistic effect under high-load working conditions: the increase of the supplementary trigger threshold advances the start timing of supply, and the decrease of the water supply capacity threshold lowers the water quality constraint threshold for upstream stages, and the two together expand the feasible window for supply triggering, so that supply can be started before the water quality deteriorates severely. If only a single strategy that threshold changes with load is adopted (e.g., only adjusting the supplementary trigger threshold), although supply can be triggered in advance under high-load working conditions, if the water quality constraint of the upstream stage remains unchanged, supply may still fail to be implemented due to the unsatisfaction of upstream stage conditions, and the problem of supply lag cannot be effectively solved.

[0073] Second, in the present application, the effective washing capacity index of the (i+1)-th stage water washing tank is used as the constraint condition for supply to the i-th stage, which makes use of the inherent water quality gradient structure in the countercurrent water washing system. In a countercurrent system, the water quality of a high-numbered stage (outlet end) is naturally better than that of a low-numbered stage (inlet end), and this gradient structure provides a natural priority basis for inter-stage coordination. Allowing supply to the i-th stage when the water quality of the (i+1)-th stage is sufficient, and suspending supply to the i-th stage when the water quality of the (i+1)-th stage deteriorates to prioritize guaranteeing the water quality closer to the outlet end. This coordination logic effectively utilizes the gradient characteristics of the countercurrent system, rather than simple average resource allocation.

[0074] In one possible implementation, the effective washing capacity index can be calculated as follows: Eeffective(i) = [kmaximumikshorti] ÷ [kmaximumi - k0]. Where kshorti is the conductivity of the i-th stage washing tank after temperature compensation and short-time moving average; kmaximumi is the maximum permissible conductivity of the i-th stage washing tank; and k0 is the reference conductivity of fresh water.

[0075] It can be understood that the effective washing capacity index has a range of [0,1]. When kshorti = k0, the washing capacity index i = 1, indicating that the water quality is equivalent to fresh water and the washing capacity is fully sufficient; when kshorti = klargei, the effective washing capacity index i = 0, indicating that the water quality has reached the maximum allowable value and the washing capacity is completely exhausted. In the calculation, if Eeffective(i) < 0, then let Eeffective(i) = 0; if Eeffective(i) > 1, then let Eeffective(i) = 1.

[0076] Specifically, the maximum allowable conductivity of each stage of the washing tank is set according to its position in the counter-current system. The stage closer to the inlet treats the products with the highest contaminant load, and its washing water conductivity is naturally higher, so the maximum allowable conductivity is higher; the stage closer to the outlet treats products that have been basically washed clean, and needs to maintain cleaner water quality to ensure the quality of the final product, so the maximum allowable conductivity is lower.

[0077] The method for determining the baseline conductivity k0 of fresh water can be as follows: during the system commissioning phase and after each change of the fresh water supply source, the operator takes a sample from the sampling port of the fresh water storage tank, uses a calibrated conductivity meter to measure its conductivity at a standard temperature of 25°C, and takes the average value of 5 consecutive measurements as k0.

[0078] For example, the method for determining the maximum permissible conductivity is as follows: under the condition that the water supply to each level of the washing tank is closed and the water flows naturally in the countercurrent direction, production tests are conducted with products under different loads, and the conductivity of each level of the washing tank is recorded when it reaches a steady state; at the same time, the residual protein content of the products after each level of washing is detected, and the conductivity of each level is found when the residual protein content is exactly equal to the quality standard limit, which is the maximum permissible conductivity of each level.

[0079] In one possible implementation, the incremental water supply is calculated when all three conditions are met simultaneously.

[0080] The replenishment water volume adopts a proportional control strategy. The formula for calculating the incremental replenishment water volume can be: ΔQi(t)=Qi×(1-Eeffective(i)÷E1i(t))×ki. Where, Qi is the maximum allowable replenishment flow rate of the replenishment water pipeline of the i-th stage washing tank; ki is the adjustment coefficient (which can be set according to actual needs, with a value range of 0.3 to 1.0, and in this embodiment, ki=0.5). ki is used to adjust the overall replenishment intensity to avoid excessive replenishment at one time when there is a large deviation, which would cause water flow impact.

[0081] The method of controlling the increase of the replenishment water volume is not limited to the proportional control strategy in this embodiment, but may also include, but is not limited to: on-off control (directly switching the valve of the replenishment water pipeline from the closed state to the preset opening degree), step control (gradually increasing the replenishment water volume according to the preset multi-level flow gradient), etc.

[0082] The control can increase the supply water volume by: the control device outputting a control signal to increase the opening of the electric proportional regulating valve on the supply water pipeline of the i-th stage washing tank from the current opening to the target opening, thereby increasing the flow rate of the supply water pipeline from the current flow rate to the target flow rate.

[0083] It is understandable that the formula for calculating the incremental replenishment water volume means that the lower the washing capacity index is than the replenishment trigger threshold, the larger the replenishment amount. When the washing capacity index equals the replenishment trigger threshold (just triggered), ΔQi=0; when the washing capacity index is much lower than the replenishment trigger threshold (severe water quality deterioration), ΔQi approaches Qi×ki (ki times the maximum replenishment amount), achieving proportional replenishment that is directly proportional to the degree of water quality deterioration. Then, the control device, based on the replenishment water volume, converts the flow demand into a corresponding valve opening percentage by adjusting the valve's flow-opening characteristic curve, and outputs this as an analog signal to the regulating valve.

[0084] In one possible implementation, total flow coordination is performed when multiple stages of the washing tank simultaneously meet the replenishment conditions.

[0085] It is understandable that when multiple stages simultaneously meet the replenishment conditions within the same control cycle, the sum of the replenishment flow rates of each stage must not exceed the maximum water supply capacity Q_total of the fresh water supply main. Total flow coordination can be the process of allocating the available fresh water flow rate among the stages that meet the conditions according to priority rules, under the constraint of limited total water supply capacity.

[0086] For example, the priority rules for total flow coordination are as follows: First, all levels that meet the replenishment conditions are sorted from low to high according to their washing capacity index. The level with the lowest washing capacity index receives the highest replenishment priority (because a lower washing capacity index indicates worse water quality and is closer to the non-compliance threshold, making replenishment more urgent). When the washing capacity index is the same, the level with the higher number (closer to the outlet) receives higher priority (because it has a more direct impact on the final product quality). Then, the replenishment flow is allocated sequentially from high to low priority: the allocation amount for the current level is min{ΔQi, Q_total - total allocated amount}. The total allocated amount is added to the allocation amount for the current level, and the allocation continues to the next level until Q_total is exhausted or all levels that meet the conditions have been allocated. Then, the control device, based on the actual replenishment flow allocated to each level, converts the flow demand into the corresponding valve opening percentage by adjusting the flow-opening characteristic curve of the valve, and outputs it to the regulating valves of each level through analog signals.

[0087] In one possible implementation, the method for controlling the parameters of multi-stage countercurrent washing of latex products also includes: If the effective washing capacity index of the i-th stage washing tank is greater than the first stop threshold, the increase in the replenishment water flow to the i-th stage washing tank is stopped. The first stop threshold is greater than or equal to the replenishment trigger threshold.

[0088] It can be understood that the first stopping threshold E_stop(t) = clip{E1i(t) + h, E_down + h, E_up + h}, where h is the hysteresis value (which can be 0.08). The purpose of the hysteresis value is to form a hysteresis interval (with a width of h) between the replenishment trigger threshold and the stopping threshold, so as to ensure that once replenishment is triggered, the washing capacity index must be increased to a distance h above the trigger threshold before stopping, preventing the oscillation phenomenon of repeated triggering and stopping near the trigger threshold due to normal fluctuations in conductivity.

[0089] In one possible implementation, the method for controlling the parameters of multi-stage countercurrent washing of latex products also includes: If the effective washing capacity index of the (i+1)th stage washing tank is less than the second stop threshold, the increase in the replenishment water flow to the i-th stage washing tank is stopped. The second stop threshold is less than or equal to the water supply capacity threshold.

[0090] It can be understood that the second stopping threshold E2stop(t) = clip{E2i+1(t)-h, Esmall-h, ELarge-h}, where h is the hysteresis value. When the washing capacity index of the (i+1)th stage washing tank drops below the second stopping threshold, it indicates that the upstream water quality has fallen below the system-level coordination requirements. Fresh water should be prioritized for supplying stages closer to the outlet, and the increase in the replenishment water volume of stage i should be controlled and stopped. The purpose of the second stopping condition is that the water quality of the water source stage is insufficient to safely maintain the replenishment of the downstream stage.

[0091] In one possible implementation, the method for controlling the parameters of multi-stage countercurrent washing of latex products also includes: S401, when the total number of stages in the washing tank is greater than three, and the (i+1)th stage washing tank is in the washing working state, obtain the washing load parameters of the multi-stage countercurrent washing device.

[0092] For example, when the (i+1)th stage water washing tank is in the water washing operation state, the water washing load parameters of the multi-stage countercurrent water washing device can be obtained. At this time, i is a positive integer greater than or equal to 1 and less than or equal to the total number of stages of the water washing tank minus 2.

[0093] S402, based on the washing load parameters, determine the second replenishment threshold of the (i+1)th stage washing tank and the second water supply threshold of the (i+2)th stage washing tank. The second replenishment threshold increases with increasing washing load parameters, while the second water supply threshold decreases with increasing washing load parameters.

[0094] For example, the second critical washing index Ei+1 corresponding to the washing load parameter can be determined based on the correspondence between the washing load parameter and the effective washing capacity index of the (i+1)th stage washing tank. The second supplementary threshold is then determined based on the second critical washing index.

[0095] Specifically, the method for determining the correspondence between the washing capacity index and the target washing load can be as follows: Under different washing load conditions (by changing the product formula, production line speed, and replenishment water volume to obtain different combinations of washing load values), in each group of experiments, the replenishment water volume of the (i+1)th stage washing tank is gradually reduced until the conductivity of that stage reaches a steady state. Then, samples are taken to test the residual protein content of the latex product after that stage of washing. When the residual protein content is exactly equal to the quality standard limit (which can be obtained by consulting industry rules or experimental manuals), the EWCi+1 value of that stage at this time (i.e., the washing capacity index of stage i+1 at this time) is recorded as E_critical(i+1) under that washing load value. Multiple (washing load value, E_critical(i+1)) data points are obtained through multiple groups of experiments, and a corresponding relationship curve is fitted or a lookup table is established.

[0096] For example, after obtaining the correspondence curve or establishing a lookup table, the curve or table can be iterated to find the second critical washing index Eclin(i+1) corresponding to the water washing load value that is the same as the target water washing load of the (i+1)th level water washing tank. Then, based on the second critical washing index and the safety margin value, the second supplementary threshold is determined. The formula for calculating the supplementary trigger threshold can be E1i(t) = clip{Eclin(i+1) + Δi, Elower, Eupper}.

[0097] In one possible implementation, the second water supply threshold can be determined based on the basic water supply capacity threshold, the current level's water washing load value, and the water supply source load sensitivity coefficient. The formula for calculating the water supply capacity threshold is: E2i+1(t)=clip{Ebase-βi×water washing load parameter WLP(t),Esmall,Elarge}.

[0098] In one possible implementation, S402, determining the second supplementary threshold for the (i+1)th stage washing tank based on the washing load parameters includes: Based on the correspondence between the washing load parameters of the (i+1)th stage washing tank and the effective washing capacity index, the second critical washing index corresponding to the washing load parameters is determined.

[0099] The second supplementary threshold is determined based on the second critical washing index.

[0100] S403, when the i+1 level water washing tank is in the water washing working state, the effective washing capacity index of the i+1 level water washing tank is less than or equal to the second supplementary threshold, and the effective washing capacity index of the i+2 level water washing tank is greater than or equal to the second water supply threshold, the supplementary water supply volume of the i+1 level water washing tank through the supplementary water supply pipe is controlled to increase.

[0101] When the (i+1)th stage washing tank is in washing operation, the effective washing capacity index of the (i+1)th stage washing tank is less than or equal to the second replenishment threshold, and the effective washing capacity index of the (i+2)th stage washing tank is greater than or equal to the second water supply threshold, the replenishment water volume of the replenishment water pipeline can be calculated. Then, based on the replenishment water volume, the control device converts the flow demand into the corresponding valve opening percentage by adjusting the valve's flow-opening characteristic curve, and outputs it to the regulating valve as an analog signal.

[0102] In one possible implementation, the method for controlling the parameters of multi-stage countercurrent washing of latex products also includes: If the effective washing capacity index of the (i+1)th stage washing tank is greater than the third stop threshold, the increase in the replenishment water volume of the (i+1)th stage washing tank is stopped. The third stop threshold is greater than or equal to the second replenishment threshold.

[0103] The formula for calculating the third stopping threshold is: E3stop(t) = clip{E1(i+1)(t) + h, Edown + h, Eup + h}, where E1(i+1)(t) is the second replenishment threshold of the (i+1)th stage washing tank, and h is the hysteresis value, which is 0.08. The third stopping threshold is greater than or equal to the second replenishment threshold. Its purpose is to form a hysteresis interval between the second replenishment threshold and the third stopping threshold, preventing the replenishment of the (i+1)th stage washing tank from being repeatedly triggered and stopped near the second replenishment threshold due to normal conductivity fluctuations.

[0104] In one possible implementation, the method for controlling the parameters of multi-stage countercurrent washing of latex products also includes: If the effective washing capacity index of the (i+2)th stage washing tank is less than the fourth stop threshold, the increase in the water supply to the (i+1)th stage washing tank is stopped. The fourth stop threshold is less than or equal to the second water supply threshold.

[0105] The calculation formula of the fourth stop threshold is: E4_stop(t)=clip{E2(i+2)(t)-h, E_min-h, E_max-h}, wherein E2(i+2)(t) is the second water supply threshold of the (i+2)-th stage washing tank, h is the hysteresis value, which is 0.08. The fourth stop threshold is less than or equal to the second water supply threshold, which aims to stop replenishing the (i+1)-th stage in time when the effective washing capacity index of the (i+2)-th stage washing tank drops to a certain hysteresis interval below the second water supply threshold, so as to avoid inter-stage resource allocation imbalance caused by water quality deterioration of the upstream stage.

[0106] In a possible implementation, the effective washing capacity index is calculated according to the electrical conductivity of the washing tank, the maximum allowable electrical conductivity of the corresponding stage and the reference electrical conductivity of fresh water, and the electrical conductivity of the washing tank is the temperature-compensated electrical conductivity.

[0107] In a possible implementation, when the stop condition is triggered, the control device does not completely close the regulating valve immediately, but closes it gradually at a preset valve closing rate (for example, reducing the valve opening by 20% in each control cycle, and completely closing within 5 control cycles, that is, about 5 minutes), so as to avoid water hammer effect in the pipeline and sudden change of water quality at all stages caused by sudden valve closing. After replenishment is stopped, the system continues to monitor the effective washing capacity index and washing load value of each stage, and if the subsequent conditions are met again, replenishment is triggered again.

[0108] In a possible implementation, when the effective washing capacity index E_effective(i) of the i-th stage washing tank is greater than the replenishment trigger threshold E1i(t) and less than or equal to the stop replenishment threshold E_stop(t) (that is, E1i(t)<E_effective(i)≤E_stop(t)), the increment of replenishment water inflow ΔQi(t) can be taken as zero at this time, and the regulating valve keeps the current opening unchanged, forming a valve dead zone control behavior. The purpose of the dead zone design is to avoid frequent adjustment of the valve opening caused by normal fluctuations of water quality near the trigger threshold, and improve the stability of the control system. When E_effective(i) recovers to above E_stop(t), the stop condition is satisfied, and the smooth valve closing process is executed.

[0109] In a possible implementation, the effective washing capacity index of all washing tanks in the washing working state can be monitored; when it is monitored that the effective washing capacity index of at least two adjacent stage washing tanks are all lower than their corresponding replenishment trigger thresholds, and the duration exceeds the preset time threshold, the system is determined to be in a high-load emergency state; in the emergency state, the requirement for the effective washing capacity index of the (i+1)-th stage washing tank is temporarily ignored, and the replenishment water inflow of the i-th stage washing tank is directly controlled to increase until the effective washing capacity index of the i-th stage washing tank recovers to above the replenishment trigger threshold or the emergency state is relieved. The purpose of this emergency measure is to prevent control stagnation caused by rapid simultaneous deterioration of water quality at all stages.

[0110] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0111] Corresponding to the multi-stage countercurrent washing parameter control method for latex products described in the above embodiments, this application also provides a multi-stage countercurrent washing parameter control system for latex products. Each unit of this system can realize each step of the multi-stage countercurrent washing parameter control method for latex products. Figure 5 The diagram shows a structural block diagram of a multi-stage countercurrent water washing parameter control system for latex products provided in an embodiment of this application. For ease of explanation, only the parts related to the embodiments of this application are shown.

[0112] Reference Figure 5 The multi-stage countercurrent washing parameter control system for latex products includes: The detection unit is used to acquire the operating status of the washing system and the water quality parameters of each washing tank. The operating status is used to indicate the working status of each washing tank, and the water quality parameters include at least the conductivity of the washing water in each washing tank.

[0113] The acquisition unit is used to acquire the washing load parameters of the multi-stage countercurrent washing device when the operating status indicates that the i-th stage washing tank is in the washing operation state. Here, i is a positive integer greater than or equal to 1 and less than the total number of stages of the washing tank. The washing load parameters are calculated based on the long-term sliding average conductivity of the inlet washing tank of the multi-stage countercurrent washing device after temperature compensation, the production line speed, and the washing difficulty coefficient of the current batch.

[0114] The calculation unit is used to determine the supplementary trigger threshold of the i-th level washing tank and the water supply capacity threshold of the (i+1)-th level washing tank based on the washing load parameters. The supplementary trigger threshold increases with the increase of the washing load parameters, while the water supply capacity threshold decreases with the increase of the washing load parameters.

[0115] The control unit is used to control the increase of the replenishment water volume of the i-th stage washing tank through the replenishment water inlet pipe when the i-th stage washing tank is in the washing operation state, the effective washing capacity index of the i-th stage washing tank is less than or equal to the replenishment trigger threshold, and the effective washing capacity index of the i+1-th stage washing tank is greater than or equal to the water supply capacity threshold.

[0116] It should be noted that the information interaction and execution process between the above systems / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0117] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units is merely an example. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the system can be divided into different functional units to complete all or part of the functions described above. The functional units in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0118] This application also provides a multi-stage countercurrent water washing device. Figure 6 This is a schematic diagram of the control device of a multi-stage countercurrent water washing device provided in an embodiment of this application. Figure 6 As shown, the control device 6 in this embodiment includes: at least one processor 60 ( Figure 6 Only one is shown in the image), at least one memory 61 ( Figure 6 (Only one is shown in the image) and a computer program 62 stored in the at least one memory 61 and executable on the at least one processor 60. When the processor 60 executes the computer program 62, it causes the control device 6 to implement the steps in any of the above embodiments of the multi-stage countercurrent water washing parameter control method for latex products, or causes the control device 6 to implement the functions of each unit in the above system embodiments.

[0119] For example, the computer program 62 may be divided into one or more units, which are stored in the memory 61 and executed by the processor 60 to complete this application. The one or more units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 62 in the control device 6.

[0120] The multi-stage countercurrent washing device may include N-stage washing tanks (N≥3) arranged sequentially along the conveying direction of the latex products, a conductivity sensor, an electric proportional regulating valve, and a control device 6. The control device 6 is electrically connected to the conductivity sensor and the electric proportional regulating valve. The conductivity sensor is installed 20 to 30 cm below the liquid level in the middle of each washing tank. The electric proportional regulating valve is installed on the replenishment water inlet pipe. One end of all replenishment water inlet pipes connects to the middle or bottom of the side of each washing tank, and the other end of all replenishment water inlet pipes connects to the fresh water supply main pipe. The fresh water supply main pipe draws water from the fresh water storage tank via a booster pump. The water supply capacity of the main pipe is determined by the power of the booster pump and the pipe diameter. The control device 6 may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will understand that… Figure 6 This is merely an example of control device 6 and does not constitute a limitation on control device 6. It may include more or fewer components than shown, or combine certain components, or different components, such as input / output devices, network access devices, buses, etc.

[0121] The processor 60 can be a Central Processing Unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0122] In some embodiments, the memory 61 may be an internal storage unit of the control device 6, such as a hard disk or memory of the control device 6. In other embodiments, the memory 61 may be an external storage device of the control device 6, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the control device 6. Furthermore, the memory 61 may include both internal storage units and external storage devices of the control device 6. The memory 61 is used to store operating systems, applications, bootloaders, data, and other programs, such as the program code of computer programs. The memory 61 can also be used to temporarily store data that has been output or will be output.

[0123] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in any of the above method embodiments.

[0124] This application provides a computer program product that, when run on a multi-stage counter-current washing device, enables the multi-stage counter-current washing device to perform the steps in any of the above-described method embodiments.

[0125] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying computer program code to a multi-stage countercurrent washing device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, such as a USB flash drive, a portable hard drive, a magnetic disk, or an optical disk.

[0126] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0127] Those skilled in the art will recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0128] In the embodiments provided in this application, it should be understood that the disclosed multi-stage countercurrent washing parameter control system / device and method for latex products can be implemented in other ways. For example, the embodiments of the multi-stage countercurrent washing parameter control system / device for latex products described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0129] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0130] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for controlling parameters of multi-stage countercurrent washing of latex products, characterized in that, The method is applied to a multi-stage countercurrent washing device, which includes at least three washing tanks arranged sequentially along the conveying direction of the latex products. Washing water flows sequentially through each washing tank in the opposite direction to the conveying direction of the latex products. Each washing tank is equipped with an independent replenishment water pipe connected to a main fresh water supply pipe. The operating status of the washing system and the water quality parameters of each washing tank are obtained. The operating status is used to indicate the working status of each washing tank. The water quality parameters include at least the conductivity of the washing water in each washing tank. When the operating status indicates that the i-th stage washing tank is in the washing working state, the washing load parameters of the multi-stage countercurrent washing device are obtained; where i is a positive integer greater than or equal to 1 and less than the total number of stages of the washing tank, and the washing load parameters are calculated based on the long-term sliding average conductivity of the inlet washing tank of the multi-stage countercurrent washing device after temperature compensation, the production line speed, and the washing difficulty coefficient of the current batch. Based on the washing load parameters, the supplementary trigger threshold of the i-th level washing tank and the water supply capacity threshold of the (i+1)-th level washing tank are determined; wherein, the supplementary trigger threshold increases with the increase of the washing load parameters, and the water supply capacity threshold decreases with the increase of the washing load parameters. When the i-th level washing tank is in the washing operation state, the effective washing capacity index of the i-th level washing tank is less than or equal to the supplementary trigger threshold, and the effective washing capacity index of the (i+1)-th level washing tank is greater than or equal to the water supply capacity threshold, the supplementary water supply volume of the i-th level washing tank through the supplementary water supply pipeline is controlled to increase.

2. The method for controlling parameters of multi-stage countercurrent washing of latex products as described in claim 1, characterized in that, The step of determining the supplementary trigger threshold of the i-th level washing tank based on the washing load parameters includes: Based on the correspondence between the washing load parameters and the effective washing capacity index of the i-th level washing tank, the first critical washing index corresponding to the washing load parameters is determined. The supplementary trigger threshold is determined based on the first critical washing index.

3. The method for controlling parameters of multi-stage countercurrent washing of latex products as described in claim 1, characterized in that, The method further includes: If the effective washing capacity index of the i-th stage washing tank is greater than the first stop threshold, the increase in the replenishment water volume of the i-th stage washing tank is stopped; wherein, the first stop threshold is greater than or equal to the replenishment trigger threshold.

4. The method for controlling parameters of multi-stage countercurrent washing of latex products as described in claim 1, characterized in that, The method further includes: If the effective washing capacity index of the (i+1)th stage washing tank is less than the second stop threshold, the increase in the replenishment water volume of the i-th stage washing tank is stopped; wherein, the second stop threshold is less than or equal to the water supply capacity threshold.

5. The method for controlling parameters of multi-stage countercurrent washing of latex products as described in claim 1, characterized in that, The method further includes: When the total number of stages in the washing tank is greater than three, and the (i+1)th stage washing tank is in the washing working state, the washing load parameters of the multi-stage countercurrent washing device are obtained. Based on the washing load parameters, a second replenishment threshold for the (i+1)th stage washing tank and a second water supply threshold for the (i+2)th stage washing tank are determined; wherein, the second replenishment threshold increases with the increase of the washing load parameters, and the second water supply threshold decreases with the increase of the washing load parameters. When the (i+1)th level washing tank is in the washing operation state, the effective washing capacity index of the (i+1)th level washing tank is less than or equal to the second replenishment threshold, and the effective washing capacity index of the (i+2)th level washing tank is greater than or equal to the second water supply threshold, the replenishment water volume of the (i+1)th level washing tank via the replenishment water inlet pipe is controlled to increase.

6. The method for controlling parameters of multi-stage countercurrent washing of latex products as described in claim 5, characterized in that, The step of determining the second replenishment threshold of the (i+1)th stage washing tank based on the washing load parameters includes: Based on the correspondence between the washing load parameters and the effective washing capacity index of the (i+1)th level washing tank, the second critical washing index corresponding to the washing load parameters is determined. The second supplementary threshold is determined based on the second critical washing index.

7. The method for controlling parameters of multi-stage countercurrent washing of latex products as described in claim 5, characterized in that, The method further includes: If the effective washing capacity index of the (i+1)th stage washing tank is greater than the third stop threshold, the increase in the replenishment water volume of the (i+1)th stage washing tank is controlled to stop; wherein the third stop threshold is greater than or equal to the second replenishment threshold.

8. The method for controlling parameters of multi-stage countercurrent washing of latex products as described in claim 5, characterized in that, The method further includes: If the effective washing capacity index of the (i+2)th stage washing tank is less than the fourth stop threshold, the increase in the replenishment water volume of the (i+1)th stage washing tank is stopped; wherein the fourth stop threshold is less than or equal to the second water supply threshold.

9. The method for controlling parameters of multi-stage countercurrent washing of latex products as described in claim 1, characterized in that, The effective washing capacity index is calculated based on the conductivity of the washing tank, the maximum allowable conductivity of the corresponding grade, and the baseline conductivity of fresh water. The conductivity of the washing tank is the conductivity after temperature compensation.

10. A multi-stage countercurrent water washing device, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method as claimed in any one of claims 1 to 9.

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