A control method for a module filtering direct drinking water

Abstract

The application relates to the technical field of water filtration, in particular to a module filtration direct drinking water control method, which is applied to a direct drinking water equipment containing a pretreatment unit, a front-end high-pressure pump, a filtration module, a pressure tank and a water supply pipeline. Data are collected in real time through a water production side pressure sensor and a flowmeter, constant pressure water supply is implemented with a first target pressure and a second target pressure at peak and off-peak periods respectively, a maximum safe flow that can be dynamically updated is set, the high-pressure pump output is limited and pressure tank pressure compensation water supply is switched when the instantaneous flow exceeds the limit, the pressure tank water storage is preferentially consumed when the off-peak demand is lower than the threshold value, the high-pressure pump is started again when the water quantity is lower than the lower limit, a pipe network hydraulic residence time model is established, a backflow electric valve and a sterilization device are opened when the residence exceeds the threshold value, the microbial risk is reduced, and the water supply stability is improved.

Description

Technical Field

[0001] This application relates to the field of water filtration technology, specifically a module filtration method for controlling direct drinking water. Background Technology

[0002] Traditional direct drinking water equipment typically employs a two-stage pressurization mode: municipal water (after pre-filtration) is first pressurized by a front-end high-pressure pump unit, filtered through high-precision filtration membranes (such as ultrafiltration or nanofiltration membranes), and the resulting water is stored in a normal or low-pressure water tank; when a user needs water, a second high-pressure pump unit at the back end draws water from the tank, performs secondary pressurization, and then delivers it to the point of use. This traditional process has the following significant drawbacks: First, the system includes two pump units (a high-pressure pump station before the membrane and a constant-pressure water supply pump unit after the membrane), resulting in a complex mechanical structure and increased potential for failures and maintenance costs during operation; second, the water tank storing the filtered water is usually not completely sealed, making it susceptible to bacterial growth upon contact with air, posing a risk of secondary contamination and affecting drinking water safety.

[0003] To address the aforementioned issues, there is an urgent need for a new direct drinking water control technology that is highly integrated, reliable in operation, and can effectively ensure water quality safety.

[0004] In view of this, this application proposes a control method for module-filtered direct drinking water. Summary of the Invention

[0005] To achieve the above objectives, this application provides a control method for module-filtered direct drinking water, the specific technical solution of which is as follows:

[0006] A control method for a module-filtered direct drinking water system is applied to a direct drinking water device. The device includes, in sequence along the water flow direction, a pretreatment unit, a front-end high-pressure pump, a filter module, a pressure tank, and a water supply pipeline. The filter module's water production side is equipped with a pressure sensor and a flow meter. The device also includes a return pipeline connected between the end of the water supply pipeline and the inlet of the front-end high-pressure pump, the return pipeline being equipped with a sterilization and disinfection device and a normally closed electric valve. The control method includes:

[0007] The pressure data from the pressure sensor and the instantaneous flow data from the flow meter are collected in real time.

[0008] During the preset peak water usage period, constant pressure water supply is achieved by adjusting the operating parameters of the front-end high-pressure pump, with the first target pressure value set as the target value.

[0009] During the preset off-peak water usage period, a constant pressure water supply is achieved by adjusting the operating parameters of the front-end high-pressure pump, with the second target pressure value set as the target value.

[0010] The maximum safe flow rate is preset and dynamically updated. When the instantaneous flow rate data is detected to be greater than or equal to the maximum safe flow rate, the power output of the front-end high-pressure pump is limited, and the pressure is switched to be supplemented by the pressure tank to keep the pressure environment in the pipeline constant and to supplement water supply.

[0011] During the off-peak water usage period, when the water demand is detected to be lower than the threshold, the pressure stored in the pressure tank is used first to stabilize the water supply in the pipeline until the pressure in the pressure tank is lower than the set lower limit before the front-end high-pressure pump is started.

[0012] A hydraulic retention time calculation model for the pipeline network is established to calculate the static time of the water at the end of the pipeline network. When the retention time exceeds the risk threshold for microbial growth, the electric valve on the return pipeline is opened and the sterilization and disinfection device is activated, so that the water stored in the pipeline is sterilized and then returned to the pretreatment unit and the front-end high-pressure pump.

[0013] Preferably, the filtration module is an ultrafiltration membrane module; the control method further includes an ultrafiltration membrane maintenance step: real-time monitoring of the transmembrane pressure difference and permeate flux of the ultrafiltration membrane module, wherein the transmembrane pressure difference is determined based on the difference between the influent pressure and the permeate pressure of the ultrafiltration membrane module;

[0014] When the permeate flow rate drops to a preset percentage of the initial value, or when the preset backwash time is reached, the backwash process is executed, and the ultrafiltration permeate is used for backwashing at a preset pressure.

[0015] Record the initial transmembrane pressure difference. When the operating transmembrane pressure difference is higher than a preset threshold and backwashing is ineffective, start the chemical cleaning procedure. The chemical cleaning procedure includes: backwashing the ultrafiltration membrane module with cleaning water containing chemical cleaning agent.

[0016] Preferably, the filtration module is a nanofiltration membrane assembly; the control method further includes a concentrate flow rate adjustment step: adjusting the concentrate flow rate through a regulating valve according to the incoming water quality parameters, and controlling the product water recovery rate to be within a preset recovery rate range or to reach a preset recovery rate target value.

[0017] Preferably, the filtration module comprises an ultrafiltration membrane module and a nanofiltration membrane module arranged in series; the direct drinking water equipment is equipped with a conductivity meter on the main water production pipeline; the control method further includes a water quality adjustment step.

[0018] Set the target conductivity range;

[0019] Based on the total permeate conductivity value detected in real time by the conductivity meter, the opening of the regulating valves on the ultrafiltration permeate pipeline and the nanofiltration permeate pipeline is dynamically adjusted. By changing the mixing ratio of the two permeates, the total permeate conductivity is maintained within the target conductivity range.

[0020] Preferably, limiting the power output of the front-end high-pressure pump means locking the pump's speed or frequency at the current value or reducing it to a safe value, so that it no longer increases with pressure feedback.

[0021] Preferably, the determination condition for water demand being lower than the threshold is: the instantaneous flow rate data is continuously lower than the minimum flow rate setting value, or the real-time pressure data is continuously higher than the set margin of the second target pressure value.

[0022] Preferably, the sterilization and disinfection device is an ultraviolet germicidal lamp or an ozone generator.

[0023] Preferably, a hydraulic calculation model for the pipeline network is established based on the minimum service pressure at the most unfavorable point of the network and the total equivalent length of the network including pipe fittings.

[0024] During peak water usage periods, the first target pressure value is calculated by superimposing the head loss along the flow path, geometric elevation difference, and minimum service pressure under the design maximum flow condition.

[0025] During off-peak water usage periods, the calculated flow velocity is reduced using a low-peak flow coefficient. Based on the reduced head loss along the flow path, a second target pressure value lower than the first target pressure value is recalculated, and the operating frequency of the front-end high-pressure pump is adjusted.

[0026] Preferably, the maximum safe flow rate is set according to the maximum allowable transmembrane pressure difference and membrane flux characteristics of the filter module;

[0027] Real-time monitoring of the pressure tank back pressure, combined with the target output pressure of the front-end high-pressure pump, the pressure tank back pressure, and the osmotic pressure difference between the raw water and the product water, dynamically calculates the maximum safe flow rate.

[0028] The calculation results are verified and corrected by introducing a limit flow rate based on the physical strength of the membrane module, and an upper limit for the flow rate is set.

[0029] When the monitored instantaneous flow rate exceeds the upper limit, the power output of the front-end high-pressure pump is locked and switched to the pressure tank for water replenishment.

[0030] Preferably, the water supply pipeline is divided into micro-segments, the total volume of the pipeline network is calculated, and the instantaneous flow rate of the flow meter is integrated within the time window to obtain the total outflow volume.

[0031] Based on the effective flow determination criteria, the static duration of the water body at the end of the pipeline network relative to the previous effective flow is calculated;

[0032] When the calculated static time exceeds the risk threshold for microbial growth, it is determined that there is a risk to the water quality of the pipeline network. The electric valve of the return pipeline and the sterilization and disinfection device are opened to make the stored water form a closed loop circulation between the pretreatment unit and the front-end high-pressure pump until the circulation flow reaches a preset multiple of the total volume of the pipeline network.

[0033] The beneficial effects of this application are as follows: The technical solution of this application eliminates the traditional water tank and the rear booster pump, and adopts a fully enclosed pressure tank, which simplifies the two sets of high-pressure pumps into one set, reduces mechanical failure points, and lowers equipment complexity and maintenance costs.

[0034] The fully enclosed pressure tank and timed reflux sterilization program in this application provide dual protection, effectively avoiding the risk of secondary pollution in the water storage process and water supply network, and ensuring the safety of drinking water at the point of use.

[0035] This application automatically switches between high and low pressure settings based on peak and off-peak water usage periods, and prioritizes the use of tank energy release for water supply during off-peak periods, causing the high-pressure pump to operate intermittently or at low frequency, which can achieve significant energy-saving effects.

[0036] The technical solution of this application achieves high pressure protection through flow monitoring to prevent overpressure damage to the filter module, and provides instantaneous pressure compensation by the pressure tank to ensure continuous water supply.

[0037] The control method of this application is compatible with various filtration modules such as ultrafiltration, nanofiltration and their combinations, and can integrate corresponding intelligent cleaning and maintenance functions, so as to adapt to different water quality treatment needs and taste preferences. Attached Figure Description

[0038] Figure 1 A flowchart of a control method for module-filtered direct drinking water provided in this application;

[0039] Figure 2 The time-segmented dynamic constant pressure water supply strategy diagram provided for this application;

[0040] Figure 3 This is a schematic diagram of the dual-membrane series filtration structure provided in this application;

[0041] Figure 4 A schematic diagram of the safe backflow circulation of water in the pipeline network provided for this application. Detailed Implementation

[0042] To make the above-mentioned objectives, features and advantages of this application more readily understood, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0043] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0045] Example 1

[0046] The first embodiment of this application, as follows: Figure 1 As shown, a control method for direct drinking water using module filtration is provided.

[0047] This technical solution aims to construct a control method for modular filtration direct drinking water. The hardware configuration of the direct drinking water equipment system, along the water flow direction, consists of: a pretreatment unit, a front-end high-pressure pump, a filter module, a pressure tank, and a water supply pipeline; the pressure in the pressure tank can be digitally adjusted. Key components also include a pressure sensor and flow meter located on the water production side of the filter module, and a return pipeline connecting the end of the water supply pipeline to the inlet of the front-end high-pressure pump, equipped with an ultraviolet germicidal lamp and a normally closed electric valve. The core of this solution is to execute the following integrated control strategy through a central controller (such as a PLC or embedded microcontroller) to achieve efficient, safe, stable operation and intelligent maintenance of the direct drinking water equipment.

[0048] Step 1: Dynamic constant pressure water supply and flow safety management based on time-of-day demand. See also Figure 2 The diagram shows the dynamic constant pressure water supply strategy for different time periods, illustrating how the system sets different target pressure values ​​during peak and off-peak hours to achieve energy savings.

[0049] The core of the control strategy in this stage is to achieve dual optimization of energy efficiency and water supply stability based on the user's water usage behavior patterns, and to ensure that the filter module operates within safe parameter ranges under any operating conditions.

[0050] First, according to a preset schedule, the day is divided into peak water usage periods and off-peak water usage periods. During the preset peak water usage periods (e.g., 7:00-9:00 and 17:00-20:00 on weekdays), the peak target pressure, i.e., the first target pressure value, is used. This serves as the setpoint for the PID (Proportional-Integral-Derivative) control algorithm. Real-time acquisition of pipeline pressure data from pressure sensors is also used. As a process variable, the speed of the high-pressure pump is precisely controlled by adjusting the output frequency of the inverter connected to the front-end high-pressure pump, thereby stabilizing the pressure in the water supply pipeline. Nearby. Accordingly, during preset off-peak water usage periods (e.g., 11:00 PM to 6:00 AM the next day), the system switches to the off-peak target pressure, i.e., the second target pressure value. (in Using this as a setpoint reduces operating pressure, thereby significantly saving energy while meeting low demand.

[0051] To protect the filter module from irreversible damage caused by over-flux operation, a maximum safe instantaneous flow rate threshold is introduced. The system employs dynamic calculation and protection mechanisms. Based on the inherent characteristics of the filter module, such as the maximum allowable transmembrane pressure difference and design membrane flux, and combined with real-time acquired operating parameters, including the pressure tank's internal pressure... Calculate and continuously update When the flow meter detects the instantaneous flow data Meet the conditions This indicates that the system is facing a sudden surge in flow rate. At this point, protective measures are immediately implemented: the operating frequency of the front-end high-pressure pump is locked at its current value or forcibly reduced to a preset safe frequency, preventing it from continuing to increase power output in response to pressure drops. Simultaneously, the fully enclosed pressurized pressure tank uses its stored pressurized water to release flow into the water supply pipeline, quickly compensating for any pressure drop that may occur due to the limited output of the front-end high-pressure pump. This collaborative mechanism protects the core filtration module and improves the user's water experience under extreme water demand conditions.

[0052] During off-peak water usage periods, a micro-water supply strategy based on pressure tanks was implemented to further reduce energy consumption and decrease the start-stop frequency of the front-end high-pressure pump. Water demand below a preset threshold was determined by one of the following two conditions: (1) Instantaneous flow rate. Continuously below a minimum flow rate setting For example, the duration is not less than the preset duration. (2) Real-time pressure The pressure remains consistently higher than the low-peak target. And add a set margin. ,Right now (For example, the duration is not less than the preset duration) Once the conditions are met, the operation of the front-end high-pressure pump will stop, and the user's minute water needs (such as getting a glass of water) will be entirely met by the pressurized water stored in the pressure tank. Only when the pressure inside the pressure tank reaches a certain level will the operation cease. Descend to the preset minimum safety threshold Only then is the front-end high-pressure pump restarted to restore the system to its previous state. A constant pressure water supply mode with the goal of achieving this.

[0053] For example, to address the minimal water demand during off-peak hours, a series of parameters were set to determine when to stop the front-end high-pressure pump; instantaneous flow rate was monitored. Continuously below the minimum flow rate setting ,For example Set as Furthermore, this low-flow state lasts for at least the preset duration. ,for example Set as Real-time pressure detected The pressure remains consistently higher than the low-peak target. Add a set margin Assuming for , margin for ,Right now And the duration of this high-pressure state is not less than the preset duration. ,For example for Once any of the above conditions are met, the front-end high-pressure pump stops operating, and the user's small water usage (such as filling a glass of water) is entirely met by the pressurized water stored in the pressure tank. Only when the pressure inside the pressure tank reaches a certain level will the system stop operating. Descend to the preset minimum safety threshold For example Set as Only then will the front-end high-pressure pump be restarted to restore it to its original state. ( A constant pressure water supply mode with the goal of ).

[0054] The control scheme at this stage, through time-sharing pressure regulation, flow limit protection, and coordinated operation with the pressure tank, maximizes energy efficiency while meeting all-weather water demand, extends the service life of the front-end high-pressure pump and filter module, and improves the operational stability and safety of the entire water supply system.

[0055] Step 2: Refined operation and maintenance strategies for different filter modules.

[0056] This phase of the solution implements customized operation and automated maintenance procedures for the specific type of filtration module (ultrafiltration, nanofiltration, or both in series) to ensure filtration performance, extend membrane life, and achieve flexible control of product water quality.

[0057] When the filtration module is an ultrafiltration membrane module, automated maintenance procedures are performed. The operating status of the ultrafiltration membrane module is monitored in real time, with the key parameter being the transmembrane pressure difference. And permeate flux. Among these, transmembrane pressure difference... The pressure on the feed water side and the pressure on the product water side of the ultrafiltration membrane module (i.e., the pressure measured by the pressure sensor) The difference is calculated. The automatic backwashing procedure is triggered by one of the following two conditions: 1) The permeate flux decreases to a preset percentage of the initial flux recorded during system startup. The following; 2) The running time reaches the preset backwash interval. During backwashing, the system switches via valves to use filtered ultrafiltration permeate water at a preset backwash pressure. Backwashing the ultrafiltration membrane module can effectively remove contaminants from the membrane surface.

[0058] To address more persistent membrane fouling, the system also integrates logic for determining and executing chemical cleaning (CEB). It records the initial transmembrane pressure differential after initial equipment operation or chemical cleaning. If a transmembrane pressure differential is detected after a routine backwash, Still significantly higher than the initial value, satisfying ,in The preset differential pressure increment threshold, or the product water flux failing to recover to the preset recovery ratio. If the above conditions are met, irreversible contamination has occurred, necessitating chemical cleaning. At this point, the chemical cleaning process will be initiated by injecting cleaning water containing a chemical cleaning agent (such as sodium hypochlorite or citric acid) into the backwash line to chemically soak and clean the ultrafiltration membrane module. This series of automated maintenance operations ensures that the ultrafiltration membrane module maintains a high-flux, low-pressure-drop operating condition over the long term, minimizing manual intervention.

[0059] For example, when the filter module is an ultrafiltration membrane assembly, a backwashing procedure is automatically executed, triggered by one of the following two conditions: the permeate flux drops to a preset percentage of the initial flux recorded during initial operation. The following, for example, setting for (i.e., flux decreased) Secondly, the running time reaches the preset backwash interval. For example, setting for Once any of the above conditions are met, filtered ultrafiltration permeate will be used at a preset backwash pressure. (For example, set to) The ultrafiltration membrane module is backwashed. To address more persistent membrane fouling, a logic is also included for triggering chemical cleaning (CEB). This is based on the initial transmembrane pressure differential recorded during initial operation or after chemical cleaning. for If a transmembrane pressure differential is detected after a routine backwash, Still significantly higher than the initial value, satisfying ,in For the preset differential pressure increment threshold (e.g., set to...) That is, at this time (or the water production flux fails to recover to the preset recovery ratio) The above (e.g., setting) for If the condition is not met, it is determined that irreversible contamination has occurred, and the chemical cleaning process will be automatically initiated.

[0060] When the filtration module is a nanofiltration membrane assembly, a dynamic adjustment step for the concentrate flow rate is performed. Considering the high rejection rate of divalent ions by nanofiltration membranes, to prevent scaling on the membrane surface, the product water recovery rate of the dynamic adjustment system must be adjusted according to the raw water quality. Incoming water quality parameters are acquired in real time through linkage with online water quality analysis instruments (such as conductivity meters and hardness meters). A preset dynamic setting lookup table for the product water recovery rate is shown in Table 1 below. This lookup table calculates the optimal target value or safe recovery rate range for the current water quality based on key indicators such as the conductivity and hardness of the incoming water. Subsequently, the opening of the electric regulating valve installed on the concentrate discharge pipeline is precisely adjusted to change the concentrate discharge flow rate, thereby stabilizing the actual product water recovery rate of the nanofiltration membrane assembly within the preset ideal range. The concentrate refers to the water that fails to pass through the filter membrane during the membrane filtration process. This water carries most of the dissolved salts, minerals, organic matter, and heavy metal ions intercepted by the membrane, so its impurity concentration is significantly higher than that of the raw water before entering the equipment; hence, it is called concentrate. For example, when an increase in incoming water hardness is detected, the concentrate regulating valve is automatically opened to reduce the recovery rate and increase the concentrate flow rate to remove more salt, effectively preventing the deposition and scaling of substances such as calcium carbonate on the membrane surface. This proactive and preventative regulation is key to ensuring the long-term stable operation of the nanofiltration system.

[0061] Table 1. Lookup Table for Dynamic Setting of Permeate Water Recovery Rate

[0062]

[0063] When the filtration module consists of an ultrafiltration membrane module and a nanofiltration membrane module connected in series, a water quality conditioning step is performed. See also... Figure 3 This is a schematic diagram of a dual-membrane series filtration structure. Figure 3 The solid blue line in the diagram represents the water production path, the dashed gray line represents the wastewater path, and the orange line represents the circulation loop. Figure 3This demonstration showcases how a dual-membrane combination and bypass regulation can achieve deep water purification and customized taste. Tap water is first pressurized by a front-end high-pressure pump and then passes entirely through an ultrafiltration (UF) membrane. This coarse filtration effectively intercepts large particles such as sediment and bacteria, producing preliminary purified water while protecting downstream equipment. The water then splits into two streams: one stream is pumped through a booster pump to a nanofiltration (NF) membrane for deep desalination and heavy metal removal, while the other stream flows directly to the downstream end via a regulating valve. The two streams eventually merge, and the mineral content of the final effluent can be flexibly controlled by adjusting the opening of the bypass valve. The merged water is connected to a fully sealed pressure tank to stabilize the supply pressure. Simultaneously, an orange reflux / sterilization pipeline at the bottom of the system automatically circulates and sterilizes the water when no water is used for extended periods, preventing bacterial growth in stagnant water and ensuring users always have access to fresh, safe, and palatable drinking water. This dual-membrane series mixing and water quality regulation aims to produce drinking water with adjustable taste and mineral content. A conductivity meter is installed on the main permeate pipeline where the ultrafiltration and nanofiltration permeate pipelines converge. A target conductivity range for the total permeate is preset. , This indicates the lower limit of the target conductivity range. This indicates the upper limit of the target conductivity range. For example, when producing mineral drinking water with a suitable taste, a preset target conductivity range could be: During operation, the total conductivity of the produced water is read from the conductivity meter. Through a closed-loop feedback control logic, the opening of two electrically operated regulating valves installed on the ultrafiltration permeate pipeline and the nanofiltration permeate pipeline, respectively, is dynamically adjusted. If a closed-loop feedback control logic is detected... This indicates that the proportion of ultrafiltration water (high in minerals) in the mixed water is too high. In this case, close the ultrafiltration permeate valve slightly or open the nanofiltration permeate valve slightly. Conversely, if... If the proportion of nanofiltration water (with extremely low mineral content) is too high, the opposite adjustment will be performed. In this way, the mixing ratio of the two types of water can be precisely controlled, ensuring that the conductivity of the drinking water ultimately supplied to the user remains within the user's desired setting range, thus enabling personalized customization of water quality.

[0064] The refined control strategy at this stage provides automated solutions to the core pain points of different membrane technologies, which not only greatly improves the operational reliability and lifespan of the filter membrane, but also endows the direct drinking water equipment with the advanced function of customizing water quality on demand.

[0065] Step 3: Water quality safety assurance in the pipeline network based on the hydraulic residence time model.

[0066] To address the issue of microbial growth that may occur in drinking water at the end of the pipeline due to prolonged stagnation, this solution establishes a proactive water quality safety assurance mechanism.

[0067] The core of building a water quality safety assurance mechanism is to establish a hydraulic retention time calculation model for the pipeline network. First, based on the design drawings of the pipeline network, the total volume of the entire water supply pipeline is calculated. During the operation of the direct drinking water equipment, a calculation task is established to determine the duration of stillness of the water at the end of the pipe network. The instantaneous flow rate of the flow meter is continuously monitored. And determine the time of the last valid flow based on a valid flow criterion.

[0068] The effective flow criterion is defined as: instantaneous flow rate. Greater than or equal to a preset effective flow rate value And the duration of this state is not less than the preset duration. This standard ensures that only flow events sufficient to displace a large portion of the water in the pipe network are considered valid.

[0069] Record the end timestamp of each effective flow event, and then calculate the time difference between the current time and the end timestamp of the most recent effective flow to obtain the static duration of the water at the end of the pipeline relative to the previous effective flow. A risk threshold based on microbial growth kinetics research is preset. When calculated Exceed At that time, it was determined that there was a potential risk of microbial growth in the water quality within the pipeline network.

[0070] Once a risk of microbial growth is determined, the reflux disinfection procedure is immediately initiated. The procedure includes: 1) automatically opening the normally closed electric valve installed on the reflux line; 2) simultaneously activating the ultraviolet (UV) germicidal lamps on the reflux line. The front-end high-pressure pump is also activated, driving the water in the supply line to flow back through the reflux line between the pretreatment unit and the front-end high-pressure pump, forming a closed-loop circulation. During this circulation, all the water in the network repeatedly flows through the UV germicidal lamps, receiving high-intensity UV radiation, effectively killing bacteria and viruses in the water. The circulation process continues until the cumulative circulating water volume calculated by the flow meter reaches the total volume of the network. preset multiple (For example, exemplary, This process involves two complete cycles of replacement and disinfection of the entire pipe network volume to ensure thorough disinfection. After the disinfection cycle is completed, the normally closed electric valve closes, the ultraviolet germicidal lamp turns off, and the system enters normal standby or water supply mode.

[0071] Through proactive water quality risk management measures, this technical solution can actively eliminate the risk of secondary pollution caused by stagnant water in the pipe network due to low water consumption, ensuring that even if the water usage frequency is extremely low, users will always receive effectively disinfected and safe drinking water when they turn on the tap.

[0072] This integrated intelligent control technology solution achieves significant improvements in several aspects of direct drinking water equipment, including energy saving, operational stability, core component protection, automated maintenance, and end-user water quality assurance, through comprehensive and precise closed-loop control of water supply pressure, flow rate, membrane module status, and pipeline water quality. The solution transforms traditional passive water supply equipment into a smart water treatment system capable of proactive sensing, intelligent decision-making, and self-maintenance. This not only drastically reduces operating and maintenance costs but also fundamentally guarantees the quality and safety of drinking water for end users, demonstrating extremely high technological advancement and practical value.

[0073] Example 2

[0074] The second embodiment of this application aims to further elaborate on the core advanced algorithms in the control method of the module filtration direct drinking water equipment. Specifically, it focuses on the dynamic adaptive setting of the target water supply pressure, the precise dynamic protection of the upper limit of the filter module flow, and the proactive safety assurance of water quality at the end of the pipeline network. These strategies together constitute a complete operation control and safety management system.

[0075] Step 1: Refined setting of target water supply pressure based on pipeline hydraulic model.

[0076] To optimize the energy efficiency of direct drinking water equipment under different water loads, a method based on a pipeline hydraulic calculation model is adopted to accurately calculate and set the target pressure value of constant pressure water supply from the front-end high-pressure pump during peak and off-peak periods.

[0077] Establish a hydraulic calculation model for the water supply network. The core input parameters of this model include: the minimum service pressure required at the most unfavorable point in the network (usually the water point that is furthest away, has the greatest elevation difference, or has the smallest pipe diameter). The total equivalent length of the entire water supply network This length has already converted the local head loss of all elbows, tees, valves, and other pipe fittings into an equivalent straight pipe length; the inner diameter of each section of the pipe network ; and the maximum geometric elevation difference between the equipment outlet and the most unfavorable point. Based on these parameters, the Darcy-Weisbache equation is used to calculate the head loss along the friction path.

[0078] During the preset peak water usage period, the design maximum flow rate is used. As a calculation condition, the water flow velocity inside the pipe is calculated based on the flow rate and pipe diameter. Then, the Reynolds number is calculated to determine the flow regime and the corresponding pipe friction coefficient is found or calculated. The head loss along the flow path during peak water usage periods can be calculated using the following formula. : ;in, This is the acceleration due to gravity. The first target pressure value. It consists of three superimposed parts: First target pressure value The setpoint of the PID controller is set during peak hours to ensure that even under maximum water demand, users at the very end of the network can receive the required service pressure.

[0079] To avoid unnecessary energy waste during the pre-defined off-peak water usage periods, an off-peak flow coefficient is adopted. (in The peak flow rate is obtained by reducing the maximum design flow rate. Repeat the above hydraulic calculation process: based on Calculate the new flow rate coefficient of friction And obtain the head loss along the route during off-peak hours. Second target pressure value The corresponding calculation is as follows: ;because It is inevitable that... ,therefore Set the second target pressure value. As a constant pressure water supply setting point during off-peak hours.

[0080] For example, assume the minimum service pressure at the most unfavorable point of the pipeline network. The geometric height difference is 0.1 MPa. The head loss along the flow path is 10 meters at peak design flow. Approximately 15 meters. Based on engineering experience (10 meters of water column is approximately equal to 0.1 MPa), the water head is converted into pressure to calculate the first target pressure value: If the low peak flow coefficient Based on the approximate relationship that head loss is proportional to the square of the flow rate, the head loss along the flow path during low peak periods... Approximately rice. The central controller adjusts the operating frequency of the front-end high-pressure pump accordingly to achieve optimized constant pressure water supply in different time periods.

[0081] By implementing this hydraulic model-based pressure setting strategy, direct drinking water equipment can intelligently match the water supply pressure with actual demand, avoiding the phenomenon of maintaining excessively high pressure during low-load periods. This can significantly reduce energy consumption while ensuring service quality throughout the entire network and at all times.

[0082] Step 2: Dynamic calculation and verification of the maximum safe flow rate of the filtering module based on dual thresholds.

[0083] To provide ultimate operational safety protection for the core filtration module and prevent membrane performance degradation or physical damage caused by instantaneous flow surges, this solution implements a dual and dynamic maximum safe flow limit mechanism.

[0084] The first layer of protection in the maximum safe flow limit mechanism is the dynamically calculated maximum safe instantaneous flow threshold. The calculation of this threshold is based on the membrane water flux equation and is related to the maximum transmembrane pressure difference allowed by the membrane material. Closely related. Updated in real time. : ;in, This is the total effective membrane area of ​​the filter module, which is a fixed parameter. It is the water permeability coefficient of the filter module at standard temperature, which characterizes the inherent water production capacity of the membrane; It is a temperature correction factor used to correct the impact of water temperature changes on membrane permeability; the water temperature is acquired in real time by a temperature sensor, and adjustments are made dynamically accordingly. This value makes the calculation results closer to actual working conditions; It is the maximum permissible transmembrane pressure difference provided by the membrane manufacturer that should not impair membrane performance during long-term operation; This is the osmotic pressure difference between the raw water and the product water; for desalination membranes such as nanofiltration or reverse osmosis, the conductivity of the raw water can be measured using an online conductivity meter, and the product water can be estimated using empirical formulas. For ultrafiltration membranes, This is usually negligible.

[0085] The second layer of protection in this mechanism is the introduction of a limiting flow rate based on the physical strength of the membrane module. , It is an absolute, static safety threshold determined by the membrane module manufacturer based on its structural strength (such as the compressive strength of the central tube, the adhesive strength of the membrane, etc.) and is designed to prevent catastrophic physical damage such as membrane stretching or telescope effect caused by excessive flow rate. This value is fixed in the safety parameter configuration of the central controller.

[0086] In each control cycle of equipment operation, the current dynamic threshold is first calculated based on the above model. Then, the final traffic limit is obtained through the following verification and correction steps. : This function takes the smaller of the two. This ensures that flow limits always adhere to the most stringent safety standards. When the instantaneous flow rate monitored by the product water side flow meter... Meet the conditions At that time, the protection action defined in the first phase plan is executed: the power output of the front-end high-pressure pump is locked, and the pressure tank is instructed to release the stored pressure for water supply compensation.

[0087] This dual threshold protection mechanism will be based on dynamic limits for performance maintenance ( ) and based on physical security restrictions ( Combined with dynamic calculation. This allows the membrane to maximize its water production potential while ensuring safety and adapting to changes in water temperature and other conditions; The presence of these elements forms an insurmountable last line of defense. Together, they provide comprehensive, multi-layered, and precise protection for the filter module.

[0088] Step 3: Calculation of network quiescent time and recirculation control based on effective flow determination. See also... Figure 4 This is a schematic diagram of the safe return circulation of water in the pipeline network for this step. It shows that when the pipeline network water is detected to have been stagnant for too long (risk of microbial growth), the return valve and UV lamp are activated to form a closed-loop sterilization circuit.

[0089] To eliminate the risk of secondary microbial contamination at the end of the water supply network caused by long-term stagnant water, a process for early warning and proactive intervention of water quality risks in the network is established.

[0090] The starting point for the pipeline network water quality risk early warning and proactive intervention process is the total volume of the pipeline network. The precise calculation and setting of this data is obtained by virtually dividing the water supply pipeline into multiple micro-segments and accumulating their volumes.

[0091] The core control logic lies in determining the effective flow and tracking the duration of stillness, and in collecting instantaneous flow data from the flow meter in real time. It identifies flow events sufficient to renew the pipe network water body based on a dual-condition valid flow criterion. The valid flow criterion is: instantaneous flow rate. It must be greater than or equal to a preset effective flow threshold. Furthermore, the duration of this state must be no less than the preset effective duration. For example, setting an effective traffic threshold. Set as and the effective duration The time limit is set to 60 seconds. Only when both conditions are met simultaneously is it considered that a flow has occurred that can effectively replace the stagnant water in the pipe network.

[0092] A timestamp variable is maintained to record the end time of the most recent valid flow event. During periods without valid flow, the theoretical quiescent time at the end of the pipeline is calculated periodically. This is the time difference between the current system time and the time when the most recent valid flow ended.

[0093] Preset a microbial growth risk threshold This threshold is scientifically set based on factors such as water temperature, pipe material, and the growth curve of the target microorganisms, including the risk threshold for microbial growth. The system is set to operate on a 24-hour timeframe, meaning that if the water in the pipe network remains stagnant for more than a day without effective replenishment, the system determines there is a risk of bacterial contamination. When the controller detects... When a potential risk to the water quality in the pipe network is detected, the system automatically initiates a backflow disinfection procedure. The procedure performs a series of automated operations: opening the normally closed electric valve on the backflow pipe and activating the ultraviolet germicidal lamp; simultaneously, the front-end high-pressure pump starts operating at a set circulation flow rate, driving the stored water in the pipe network to flow back to the inlet of the front-end high-pressure pump through the backflow pipe, forming a self-circulating disinfection loop. During the circulation process, the controller integrates the flow meter data to calculate the cumulative circulating water volume in real time. When the cumulative circulating water volume reaches the total volume of the pipe network... preset multiple (For example When the controller determines that disinfection and replacement have been fully completed, it immediately closes the normally closed electric valve and the ultraviolet germicidal lamp, stops the circulation, and updates the end time of this cycle to the most recent effective flow time.

[0094] Through this precise timing and proactive intervention mechanism based on actual flow conditions, this solution extends the scope of water quality safety protection from the water treatment equipment itself to the entire transmission and distribution network. It can intelligently identify and eliminate potential sanitary dead zones, ensuring that users can obtain safe, fresh, and high-quality drinking water at any time, thus achieving closed-loop management of end-user drinking water safety.

[0095] This technical solution replaces traditional static and extensive control by introducing model-based prediction and dynamic calculation. Precise setting of water supply pressure achieves significant energy savings; dual dynamic protection of water production flow maximizes the performance and lifespan of the core filtration module; and proactive circulation and disinfection of the pipe network fundamentally eliminates concerns about end-user water quality. The integrated application of these strategies endows the direct drinking water equipment with a high degree of intelligence, adaptability, and self-maintenance capabilities, achieving a qualitative leap in improving operational economy, reliability, and user experience.

[0096] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings or direct couplings or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0097] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments under the guidance of this application without departing from the spirit and scope of protection of the claims. All of these variations are within the protection scope of this application.

Claims

1. A control method for module-filtered direct drinking water, applied to a direct drinking water device, wherein the direct drinking water device includes, in sequence along the water flow direction, a pretreatment unit, a front-end high-pressure pump, a filter module, a pressure tank, and a water supply pipeline; the filter module is equipped with a pressure sensor and a flow meter on its water production side; the direct drinking water device further includes a return pipeline connected between the end of the water supply pipeline and the inlet of the front-end high-pressure pump, the return pipeline being equipped with a sterilization and disinfection device and a normally closed electric valve; characterized in that, The control method includes: The pressure data from the pressure sensor and the instantaneous flow data from the flow meter are collected in real time. A hydraulic calculation model for the pipeline network is established based on the minimum service pressure at the most unfavorable point of the network and the total equivalent length of the network including pipe fittings. During the preset peak water consumption period, the first target pressure value is calculated by superimposing the head loss along the flow path, geometric height difference, and minimum service pressure under the design maximum flow condition. The first target pressure value is used as the set value, and constant pressure water supply is achieved by adjusting the operating parameters of the front-end high-pressure pump. During the preset off-peak water usage period, the calculated flow rate is reduced by the off-peak flow coefficient. Based on the reduced head loss along the flow rate, a second target pressure value lower than the first target pressure value is recalculated. The second target pressure value is used as the set value, and constant pressure water supply is achieved by adjusting the operating parameters of the front-end high-pressure pump. The maximum safe flow rate is set based on the maximum allowable transmembrane pressure difference and membrane flux characteristics of the filter module; the back pressure of the pressure tank is monitored in real time, and the maximum safe flow rate is dynamically calculated by combining the target output pressure of the front-end high-pressure pump, the back pressure of the pressure tank, and the osmotic pressure difference between the raw water and the product water for the current period. The calculation results are verified and corrected by introducing a limit flow rate based on the physical strength of the membrane module, and a flow rate upper limit is set. When the monitored instantaneous flow rate is greater than or equal to the flow rate upper limit, the power output of the front-end high-pressure pump is limited, and the pressure is switched to be supplemented by the pressure tank to keep the pressure environment in the pipeline constant and to supplement water supply. During the off-peak water usage period, when the water demand is detected to be lower than the threshold, the pressure stored in the pressure tank is used first to stabilize the water supply in the pipeline until the pressure in the pressure tank is lower than the set lower limit before the front-end high-pressure pump is started. A hydraulic retention time calculation model for the pipeline network is established to calculate the static time of the water at the end of the pipeline network. When the retention time exceeds the risk threshold for microbial growth, the electric valve on the return pipeline is opened and the sterilization and disinfection device is activated, so that the water stored in the pipeline is sterilized and then returned to the pretreatment unit and the front-end high-pressure pump.

2. The control method for module-filtered direct drinking water according to claim 1, characterized in that, The filtration module is an ultrafiltration membrane module; the control method further includes an ultrafiltration membrane maintenance step: real-time monitoring of the transmembrane pressure difference and permeate flux of the ultrafiltration membrane module, wherein the transmembrane pressure difference is determined based on the difference between the inlet pressure and the permeate pressure of the ultrafiltration membrane module; When the permeate flow rate drops to a preset percentage of the initial value, or when the preset backwash time is reached, the backwash process is executed, and ultrafiltration permeate is used for backwashing at a preset pressure. Record the initial transmembrane pressure difference. When the operating transmembrane pressure difference is higher than the preset threshold and backwashing is ineffective, start the chemical cleaning program. The chemical cleaning procedure includes backwashing the ultrafiltration membrane module with cleaning water containing chemical cleaning agents.

3. The control method for module-filtered direct drinking water according to claim 1, characterized in that, The filtration module is a nanofiltration membrane assembly; the control method further includes a concentrate flow rate adjustment step: according to the incoming water quality parameters, the concentrate flow rate is adjusted by a regulating valve to control the product water recovery rate to be within a preset recovery rate range or to reach a preset recovery rate target value.

4. The control method for module-filtered direct drinking water according to claim 1, characterized in that, The filtration module consists of an ultrafiltration membrane module and a nanofiltration membrane module arranged in series; the direct drinking water equipment is equipped with a conductivity meter on the main water production pipeline; the control method further includes a water quality adjustment step. Set the target conductivity range; Based on the total permeate conductivity value detected in real time by the conductivity meter, the opening of the regulating valves on the ultrafiltration permeate pipeline and the nanofiltration permeate pipeline is dynamically adjusted. By changing the mixing ratio of the two permeates, the total permeate conductivity is maintained within the target conductivity range.

5. The control method for module-filtered direct drinking water according to claim 1, characterized in that, Limiting the power output of the front-end high-pressure pump means locking the pump's speed or frequency at the current value or reducing it to a safe value, so that it no longer increases with pressure feedback.

6. The control method for module-filtered direct drinking water according to claim 1, characterized in that, The criteria for determining that the water demand is below the threshold are: the instantaneous flow rate data is continuously lower than the minimum flow rate setting value, or the real-time pressure data is continuously higher than the set margin of the second target pressure value.

7. The control method for module-filtered direct drinking water according to claim 1, characterized in that, The sterilization and disinfection device is an ultraviolet germicidal lamp or an ozone generator.

8. The control method for module-filtered direct drinking water according to claim 1, characterized in that, The water supply pipeline is divided into micro-segments, the total volume of the pipeline network is calculated, and the instantaneous flow rate of the flow meter is integrated within the time window to obtain the total outflow volume. Based on the effective flow determination criteria, the static duration of the water body at the end of the pipeline network relative to the previous effective flow is calculated; When the calculated static time exceeds the risk threshold for microbial growth, it is determined that there is a risk to the water quality of the pipeline network. The electric valve of the return pipeline and the sterilization and disinfection device are opened to make the stored water form a closed loop circulation between the pretreatment unit and the front-end high-pressure pump until the circulation flow reaches a preset multiple of the total volume of the pipeline network.

Images