Intelligent linkage control method and system of multi-stage reverse osmosis water purification equipment

Abstract

The present application relates to water purification equipment control technical field, disclose a kind of multistage reverse osmosis water purification equipment's intelligent linkage control method and system, method includes: real-time acquisition multichannel valve dry contact signal, pipeline pressure and water quality parameter;When multichannel valve dry contact signal is closed, interrupt current water production process, control raw water pump and water flow is supplied to pretreatment module, after disconnection, restore normal water production process;When pipeline pressure signal is abnormal limit, cut off high-pressure pump power supply and execute test start, if continuous test start fails to reach the set upper threshold, cut off the whole machine power output and lock operating state;Start water production process, compare water production conductivity and preset threshold, when water production conductivity value is higher than threshold, bypass discharge, not higher than threshold and change rate meet stable condition, carry out water production into tank.The present application avoids water pump dry running, guarantees backwash effect, accurately intercepts unqualified pure water in initial stage, improves equipment operation safety and effluent water quality.

Description

Technical Field

[0001] This invention relates to the field of water purification equipment control technology, and in particular to an intelligent linkage control method and system for a multi-stage reverse osmosis water purification equipment. Background Technology

[0002] Multi-stage reverse osmosis water purification equipment is widely used in various drinking water and pure water preparation scenarios. Its conventional hardware architecture typically consists of modules such as raw water supply, pretreatment, high-pressure reverse osmosis unit, and water storage. In actual operation, traditional equipment control methods often operate each hardware module independently or only use simple liquid level start-stop logic. This control strategy, which lacks deep linkage, is prone to causing a series of operational problems under complex working conditions.

[0003] When the pretreatment module reaches its set cleaning cycle and enters backwash mode, if the pure water tank happens to issue a water production request, the raw water pump's supply will be diverted by the reverse osmosis main unit's water production process. This not only prevents the pretreatment filter media from receiving sufficient hydraulic energy during cleaning, resulting in incomplete backwashing of impurities, but also causes a drop in the inlet pressure of the reverse osmosis main unit due to the rapid diversion at the front end, easily leading to cavitation damage to the high-pressure pump. Simultaneously, in the face of transient pressure fluctuations in municipal pipe networks or abnormal hydraulic conditions such as blocked pipe valves, most existing equipment lacks intelligent pressure filtering and fault identification mechanisms. Once the pipe pressure exceeds the limit, the control system usually directly reports an error and shuts down, or gets caught in a blind and frequent restart loop driven by the liquid level signal. This simplistic and crude intervention method cannot automatically filter out occasional water pipe interference and is prone to causing the water pump to run dry for extended periods and burn out the motor in the event of a water outage or other hard fault.

[0004] Regarding water quality safety, during prolonged shutdowns of reverse osmosis equipment, ion permeation inevitably occurs on both sides of the membrane chamber, leading to concentration and polarization of the internal stagnant water. While conventional equipment includes water quality monitoring during the start-up phase, the judgment logic is relatively simplistic, often relying solely on absolute conductivity values ​​without precise temperature compensation for threshold comparisons, lacking dynamic consideration of stable water quality trends. This makes it easy for initial permeate water containing high levels of impurities and fluctuating values ​​to be directly released into the tank during the initial startup phase, before the internal desalination rate has stabilized, causing contamination of the pure water tank and failing to meet the stringent requirements for end-user effluent quality. Summary of the Invention

[0005] The purpose of this invention is to provide an intelligent linkage control method and system for multi-stage reverse osmosis water purification equipment, which solves the problems of incomplete cleaning and high-pressure pump damage caused by conflicts between pretreatment backwashing and water production process requirements in existing reverse osmosis water purification equipment, blind restart and dry running of water pumps due to lack of identification mechanism when pipeline pressure is abnormal, and unqualified initial stage product water mixed into the pure water tank due to the simple water quality judgment logic at the beginning of start-up.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The first aspect of this invention provides an intelligent linkage control method for a multi-stage reverse osmosis water purification system, comprising the following steps:

[0008] Real-time acquisition of multi-way valve dry contact signals, pipeline pressure signals, and water quality parameters, and acquisition of the real-time conductivity value and the rate of change of conductivity of the produced water from the water quality parameters;

[0009] When the signal of the dry contact of the multi-way valve is determined to be closed, the current water production process is interrupted and the raw water pump is controlled to supply the output water to the pretreatment module; after the signal of the dry contact of the multi-way valve is switched to open, the normal water production process is restored.

[0010] When the pressure signal of the pipeline is found to be abnormally high, the power supply to the high-pressure pump is cut off and a test start-up action is performed.

[0011] If the cumulative number of consecutive failed start attempts reaches the set upper limit threshold for failed start attempts, the power output of the entire machine will be cut off and the operating status will be locked.

[0012] When the water production process is started, the real-time conductivity value of the produced water is compared with the preset threshold, and the action of the bypass discharge solenoid valve and the produced water inlet solenoid valve is controlled according to the comparison result.

[0013] When the real-time conductivity value of the produced water is higher than the preset threshold, bypass discharge is performed; when the real-time conductivity value of the produced water is not higher than the preset threshold and the rate of change of the produced water conductivity meets the stable condition, the produced water is fed into the tank.

[0014] Preferably, the step of real-time acquisition of multi-way valve dry contact signals, pipeline pressure signals, and water quality parameters specifically includes the following for acquiring the water quality parameters:

[0015] Continuously read dual-channel conductivity data and real-time water temperature data from the inlet and outlet of the reverse osmosis membrane module;

[0016] The original conductivity data and the real-time water temperature data are time-frame aligned based on the sampling timestamp of the internal clock.

[0017] The temperature compensation calculation process, which involves division, is performed based on thermodynamic properties. Before performing the division operation, the absolute value of the denominator term of the division operation is calculated independently.

[0018] When it is determined that the absolute value of the denominator is less than the preset first safety minimum, the previous calculation result is maintained, and the preset first safety minimum is set to 0.001;

[0019] When it is determined that the absolute value of the denominator is not less than the preset first safety minimum value, the temperature compensation calculation process is executed to convert the original conductivity data at different ambient temperatures into conductivity calculation values ​​at the standard reference temperature.

[0020] Preferably, the step of interrupting the current water production process and controlling the raw water pump to supply the output water to the pretreatment module specifically includes:

[0021] Simultaneously collect the water production process request signal input of the pure water tank liquid level status and the pretreatment backwash signal;

[0022] Using Boolean algebra operations to implement hardware-level signal interlocking, the control enable state of the high-pressure pump and the opening state of the water inlet solenoid valve are set to 0;

[0023] The high-pressure pump is powered off and stopped, and an internal timer is invoked to delay before a coil power-off command is sent to the water inlet solenoid valve.

[0024] The raw water pump is controlled to disengage from the liquid level control cycle and continuously maintain the start-up and operation state;

[0025] When the pretreatment backwash signal flips to 0, and the pretreatment backwash signal remains at 0 within a continuous time window while the pressure value of the pipeline pressure signal falls back to the safe resting range, the safe resting range is set to 0.1MPa~0.2MPa. The water production process request signal is then reintroduced into the control loop, and the inlet solenoid valve and the high-pressure pump are turned on.

[0026] Preferably, when the pipeline pressure signal is determined to have exceeded the pressure limit, the step of cutting off the high-pressure pump power supply and performing a test start-up action specifically includes:

[0027] Extract the low-pressure data before the pump and the high-pressure data before the membrane, and perform synchronous latching of the two pressure data using the same clock cycle;

[0028] A piecewise function in the time domain is constructed to transform continuously changing simulated pressure values ​​into discrete Boolean state variables;

[0029] When the low pressure data before the pump is determined to be lower than the preset low pressure threshold, or the high pressure data before the membrane is higher than the preset high pressure threshold, and the pressure values ​​of three consecutive sampling cycles exceed the limit, the abnormal result is determined to be effective, and an emergency cut-off command is issued to disconnect the power supply circuit of the high pressure pump.

[0030] The internally set condensation delay timer is activated to start the delay timer, suspending all regular water production process requests during the condensation period;

[0031] After the delay timer expires, the high-pressure pump is controlled to start for trial operation, and the pressure building observation window is opened. When the pressure data in the pressure building observation window returns to normal, the abnormal alarm record is cleared, and the cumulative number of consecutive failed trial starts recorded internally is simultaneously cleared to zero.

[0032] Preferably, the step of cutting off the power output of the entire machine and locking the operating state specifically includes:

[0033] The system counts the cumulative number of consecutive failed test starts. When the cumulative number of consecutive failed test starts reaches the set upper limit threshold for test start failure, the system enters a self-locking state, cuts off the power output of all water pump components, triggers an audible and visual locking alarm on the human-machine interface, and blocks any automatic restart action based on liquid level or timing signals. The set upper limit threshold for test start failure is set to 3 times.

[0034] Upon receiving a manual intervention instruction, the cumulative number of consecutive failed startup attempts is reset to zero, and the automatic operation permission is regained.

[0035] Preferably, before starting the water production process, the method further includes:

[0036] When the equipment finishes its water production process and enters standby monitoring mode, a sleep timer is started. When the accumulated standby time reaches the preset sleep duration limit, the raw water pump, inlet solenoid valve, and flushing solenoid valve are opened simultaneously, but the high-pressure pump is not started. The preset sleep duration limit is set to 1h to 24h.

[0037] The raw water is controlled to flow through the reverse osmosis membrane module. After the set flushing time is completed, the sleep timer is reset and the system is switched back to the standby monitoring state.

[0038] Preferably, the step of real-time acquisition of multi-way valve dry contact signals, pipeline pressure signals, and water quality parameters further includes:

[0039] The absolute value of the time interval between two sampling points is extracted independently. When the value of the time interval is determined to be less than the preset second safety minimum, the calculation result of the previous cycle is maintained and a clock synchronization abnormality flag is thrown. The preset second safety minimum is set to 0.01s.

[0040] Preferably, the preset low-pressure threshold is set in the range of 0.03MPa to 0.05MPa, and the preset high-pressure threshold is set in the range of 1.2MPa to 1.5MPa.

[0041] Preferably, in the step of obtaining the real-time conductivity value of the product water and the rate of change of the product water conductivity in the water quality parameters, the first-order rate of change of the real-time conductivity value of the product water is obtained as the rate of change of the product water conductivity.

[0042] The preset threshold for achieving the target is set to be below 50 μS / cm;

[0043] The rate of change of conductivity of the produced water meets the stability condition, specifically meaning that the first-order rate of change is less than or equal to a preset stability threshold for conductivity rate of change, which is set to 2-5 μS / (cm·s).

[0044] The second aspect of this invention provides an intelligent linkage control system for a multi-stage reverse osmosis water purification device, the intelligent linkage control system comprising: a raw water supply module, a pretreatment module, a main water processing module, and an intelligent main control module;

[0045] The raw water supply module includes a raw water tank and a raw water pump, with the output end of the raw water tank connected to the inlet end of the raw water pump;

[0046] The pretreatment module includes a multi-way valve and a quartz sand filter and an activated carbon filter controlled by the multi-way valve. The multi-way valve has a dry contact signal output port.

[0047] The main water-making module includes a security filter, an inlet solenoid valve, a high-pressure pump, a reverse osmosis membrane module, and a pure water tank. The product water end pipeline of the reverse osmosis membrane module is divided into two lines, with a product water inlet solenoid valve and a bypass discharge solenoid valve installed respectively. The outlet end of the product water inlet solenoid valve is connected to the pure water tank. A flushing solenoid valve is installed on the concentrate end pipeline of the reverse osmosis membrane module.

[0048] The main water-making module includes multiple sets of detection elements, including a conductivity probe connected to a dual-channel conductivity sensor transmitter, a low-pressure detection element, and a high-pressure detection element.

[0049] The signal input port of the intelligent main control module is connected to the dry contact signal output port, the dual-channel conductivity sensor transmitter, the low-pressure detection element, the high-pressure detection element, and the liquid level sensor, respectively. The control output port of the intelligent main control module is connected to the raw water pump, the inlet solenoid valve, the flushing solenoid valve, the high-pressure pump, the product water inlet solenoid valve, and the bypass discharge solenoid valve, respectively.

[0050] In summary, the present invention has at least one of the following beneficial technical effects:

[0051] 1. This invention, by real-time acquisition of the dry contact signals of the pretreatment multi-way valve, can automatically interrupt the current reverse osmosis water production process and force the raw water pump to direct water flow to the pretreatment module when the pretreatment module enters a backwash cycle. Combined with signal interlocking logic implemented using Boolean algebra operations, it ensures that the full water pressure and flow generated by the raw water pump are concentrated for filter media cleaning, avoiding the attenuation of cleaning kinetic energy caused by the reverse osmosis unit's diversion, thus improving the thoroughness of pretreatment cleaning. Simultaneously, the introduction of a stepped delayed power-off control mitigates water hammer impacts caused in the closed pipeline during valve switching.

[0052] 2. This invention constructs a graded pressure filtering and deadlock protection mechanism. By extracting low-pressure data before the pump and high-pressure data before the membrane and performing synchronous latching and comparison, it can accurately distinguish between transient network fluctuations and hard faults. When abnormal pressure exceeding the limit is detected, the system filters out occasional interference through built-in condensation delay and a limited number of trial start procedures. When continuous trial start failures reach the set upper limit, the system automatically cuts off the water pump power supply and enters a self-locking state, preventing the equipment from blindly and repeatedly restarting under water shortage or blockage conditions, avoiding high-pressure pump dry running cavitation and damage, and improving the safety of system operation.

[0053] 3. This invention introduces a dynamic quality control logic linked to dual conductivity levels. When the equipment reaches its dormancy threshold during standby, it automatically performs anti-deterioration flushing to suppress concentration polarization and bacterial growth within the membrane chamber. During the equipment's wake-up water production process, the control system not only obtains accurate conductivity calculations through a temperature compensation algorithm with zero-division protection, but also performs a two-dimensional joint calculation combining the real-time conductivity value of the produced water and its first-order rate of change. The solenoid valve for the produced water inlet is only opened when the conductivity value is below the acceptable threshold and the rate of change meets the stability condition, thus intercepting substandard pure water at the initial startup and ensuring the absolute safety of the final effluent water quality. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the intelligent linkage control system of the multi-stage reverse osmosis water purification equipment of the present invention;

[0055] Figure 2 This is a schematic diagram of the intelligent linkage control method for the multi-stage reverse osmosis water purification equipment of the present invention;

[0056] Figure 3 This is a schematic diagram of the intelligent test start and deadlock protection control logic flow of the present invention;

[0057] Figure 4 This is a schematic diagram of the dynamic quality control logic of the present invention. Detailed Implementation

[0058] The following is in conjunction with the appendix Figure 1 -Appendix Figure 4 The present invention will be further described in detail below.

[0059] See attached document Figure 1 The present invention provides an intelligent linkage control system for a multi-stage reverse osmosis water purification device, comprising: a raw water supply module, a pretreatment module, a main water processing module, and an intelligent main control module.

[0060] The raw water supply module includes a raw water tank and a raw water pump. The output end of the raw water tank is connected to the inlet end of the raw water pump. The outlet end of the raw water pump is connected to the downstream pipeline, and the raw water pump provides the initial water flow pressure for the subsequent water treatment process.

[0061] The pretreatment module includes a multi-way valve and a quartz sand filter and an activated carbon filter controlled by the multi-way valve. The multi-way valve is equipped with a dry contact signal output port. The inlet of the quartz sand filter is connected to the outlet of the raw water pump. The outlet of the quartz sand filter is connected to the inlet of the activated carbon filter.

[0062] The main water treatment module includes a security filter, an inlet solenoid valve, a high-pressure pump, a reverse osmosis membrane module, and a pure water tank. The inlet of the security filter is connected to the outlet of the activated carbon filter. The outlet of the security filter is connected to the inlet of the high-pressure pump via a pipeline. The inlet solenoid valve is installed on the pipeline between the security filter and the high-pressure pump. The outlet of the high-pressure pump is connected to the inlet port of the reverse osmosis membrane module. The permeate pipeline of the reverse osmosis membrane module is divided into two lines, each equipped with a permeate inlet solenoid valve and a bypass discharge solenoid valve. The outlet of the permeate inlet solenoid valve is connected to the pure water tank, which is equipped with a level sensor for monitoring water volume. Additionally, a flushing solenoid valve is installed on the concentrate pipeline of the reverse osmosis membrane module for high-flow-rate blowdown.

[0063] The main water processing module also includes multiple sets of detection elements. The inlet and product water lines of the reverse osmosis membrane module are each equipped with a conductivity probe with temperature compensation, and both are connected to a dual-channel conductivity sensor transmitter. A low-pressure detection element is installed on the inlet line of the high-pressure pump. A high-pressure detection element is installed on the outlet line of the high-pressure pump. The low-pressure and high-pressure detection elements can be either analog pressure transmitters or mechanical detection elements.

[0064] The intelligent main control module includes a pretreatment multi-way valve control unit and a reverse osmosis main unit integrated control unit that are interconnected. The signal input ports of the intelligent main control module are connected to the dry contact signal output ports of the multi-way valve, a dual-channel conductivity sensor transmitter, a low-pressure detection element, a high-pressure detection element, and the liquid level sensor of the pure water tank. The control output ports of the intelligent main control module are connected to the raw water pump, the inlet solenoid valve, the flushing solenoid valve, the high-pressure pump, the product water inlet solenoid valve, and the bypass discharge solenoid valve.

[0065] The overall water flow path and control process of the multi-stage reverse osmosis water purification system are as follows. In the conventional water production process, the intelligent main control module outputs a command to start the raw water pump. Water flows out of the raw water tank, is pressurized by the raw water pump, and then flows sequentially through the quartz sand filter, activated carbon filter, and security filter. The intelligent main control module opens the inlet solenoid valve and starts the high-pressure pump. The high-pressure pump pressurizes the water flow and sends it into the reverse osmosis membrane module. The produced water flows through the product water inlet solenoid valve and is injected into the pure water tank.

[0066] During equipment operation, the intelligent main control module cyclically collects signals from various detection elements. When the pretreatment module reaches its internally set backwash cycle, the multi-way valve closes and outputs a dry contact signal. The intelligent main control module receives this signal and interrupts the main water processing module's operating instructions, controlling the raw water supply module to direct water flow to the pretreatment module for filter media cleaning.

[0067] During the operation of the main water-making module, the intelligent main control module reads the status of the low-pressure and high-pressure detection elements in real time. When the pressure signal exceeds the limit, the intelligent main control module stops the high-pressure pump and, in conjunction with its internal timing logic, performs a trial start or cuts off the power supply to the entire system.

[0068] When the main water production module is in standby mode or at the initial startup stage, the intelligent main control module uses the system's internally recorded sleep time and the water quality parameters acquired from the dual conductivity sensors. Based on the parameter comparison results, the intelligent main control module controls the opening and closing combination of the product water inlet solenoid valve and the bypass discharge solenoid valve to complete the product water entering the tank or directly emptying it.

[0069] See attached document Figure 2 This invention provides an intelligent linkage control method for a multi-stage reverse osmosis water purification system, comprising the following steps:

[0070] S1, real-time acquisition of multi-way valve dry contact signals, pipeline pressure signals and water quality parameters;

[0071] S2, in response to the conflict between the pretreatment backwash command and the water production process request, performs directional water supply allocation based on status feedback;

[0072] S3 identifies abnormal pipeline pressure and performs graded pressure filtering and deadlock protection;

[0073] S4 controls the opening and closing combination of the bypass discharge solenoid valve and the product water inlet solenoid valve based on the standby time and the real-time conductivity change of the product water.

[0074] After powering on, the intelligent main control module continuously executes step S1 to acquire the real-time operating status parameters of the device through signal acquisition.

[0075] When the system receives a signal indicating the dry contact of the multi-way valve is closed, step S2 is triggered. The intelligent main control module interrupts the current water production process, forcing the raw water pump to enter directional water supply mode. The output water from the raw water pump is then used exclusively for cleaning the filter media in the pretreatment module. After the signal from the dry contact of the multi-way valve is disconnected, the system resumes the normal water production process.

[0076] During the water production process, the system determines whether to execute step S3 based on the pipeline pressure signal obtained in step S1. When the pipeline pressure is lower than the low-pressure threshold or higher than the high-pressure threshold, the intelligent main control module cuts off the power to the high-pressure pump and starts a delay timer. After the timer expires, the system controls the high-pressure pump to perform a trial start. If the pipeline pressure remains abnormal and reaches the set cumulative number of trial starts, the system cuts off the power output of the entire unit and locks the operating status.

[0077] When the equipment is in standby mode or during the water production process restart phase, the system executes step S4. When the equipment standby time reaches the preset sleep duration limit, the system starts the raw water pump and opens the flushing pipeline to drain the internal stagnant water. Each time the water production process is restarted, the system compares the real-time conductivity value obtained in step S1 with the preset threshold. When the real-time conductivity is higher than the preset threshold, the bypass discharge solenoid valve is opened. When the real-time conductivity is lower than the preset threshold and the rate of change meets the stability condition, the bypass discharge solenoid valve is closed and the product water inlet solenoid valve is opened.

[0078] Based on the above embodiments, the intelligent main control module, as the control core with logic operation and data processing capabilities, specifically adopts a programmable logic controller or a customized control motherboard equipped with a microprocessor in this embodiment. To accurately capture external signals, the intelligent main control module is configured with digital input ports and analog-to-digital converter input ports. Based on the above hardware architecture, step S1 specifically includes the following sub-steps:

[0079] S101, the intelligent main control module polls and reads the dry contact switching signals of the preprocessing multi-way valve through the digital input port. To avoid misjudgment caused by external electromagnetic interference, an optocoupler isolation circuit is set at the front end of the digital input port. In the specific signal processing, the intelligent main control module continuously acquires the level status of the dry contact port at a fixed time period. When the continuously read level signals remain consistent and exceed the set debouncing time limit, the intelligent main control module confirms that the dry contact signal is in a closed or open state, and then determines whether the preprocessing module has entered the backwashing cycle.

[0080] As a preferred approach, the debouncing time extreme value is typically set to 20–50 ms, based on the mechanical bounce time characteristics of conventional relay contacts, thereby filtering out transient high-frequency level jitter. For the specific circuit topology of the optocoupler isolation circuit and the code implementation of the software debouncing algorithm, those skilled in the art can configure it according to the design specifications of conventional industrial control boards. The hardware setup and conventional software development are well-known technologies in this field and will not be elaborated upon here.

[0081] S102. While acquiring the preprocessing status, the system must also monitor the hydraulic conditions of the pipeline in real time. Therefore, the intelligent main control module collects the pressure signals from the inlet and outlet pipelines of the high-pressure pump. When an analog pressure transmitter is used in the pipeline, the transmitter outputs a current or voltage signal corresponding to the current water pressure. The intelligent main control module acquires this signal using the analog input port of the analog-to-digital converter, converts it into the corresponding digital pressure values, and then compares the real-time digital pressure value of the inlet pipeline with the preset low-pressure threshold in the internal memory, and compares the real-time digital pressure value of the outlet pipeline with the preset high-pressure threshold.

[0082] In this scenario, the specific ranges for the low-pressure and high-pressure thresholds need to be rigorously calibrated based on the rated feed water pressure requirements of the reverse osmosis membrane module and the allowable net positive suction head (NPSH) curve of the high-pressure pump to accurately reflect the impact of water flow on the hardware. When mechanical detection elements are used in the pipeline, the action contacts of the detection elements are connected to the digital input port of the intelligent main control module. The intelligent main control module directly obtains switch feedback on whether the pipeline pressure exceeds the safe operating range by identifying the on / off state of the contacts.

[0083] S103, to implement dynamic safety monitoring of water quality, the intelligent main control module continuously reads dual-channel conductivity data and water temperature parameters from both the inlet and outlet of the reverse osmosis membrane module. The probe assembly of the dual-channel conductivity sensor integrates a thermistor element to simultaneously sense the real-time water temperature. After acquiring the raw conductivity data and real-time water temperature data, the intelligent main control module performs a temperature compensation calculation process.

[0084] Considering the objective differences in sampling frequency and hardware response latency among different sensors, the system performs time frame alignment on the raw conductivity data and real-time water temperature data based on the sampling timestamp of the internal clock before performing calculations. This ensures that the multi-source data within the same calculation cycle reflects completely consistent transient conditions. This alignment mechanism avoids distortion in water quality assessment caused by lag in temperature data. The system uniformly converts the raw conductivity data at different ambient temperatures into conductivity values ​​at the standard reference temperature, eliminating the impact of water temperature fluctuations on water concentration determination.

[0085] The mathematical expression used in the temperature compensation calculation based on thermodynamic properties above is as follows:

[0086] ;

[0087] In the formula, Defined as the calculated conductivity value at the standard reference temperature; Defined as the raw conductivity data acquired by the dual-channel conductivity sensor; Defined as a preset water solution temperature compensation coefficient, the value of which is mainly based on the electrolyte ion composition characteristics of the local water source. In this embodiment, its preferred range is set to 0.018~0.022 / ℃. Defined as the real-time water temperature parameter collected by the thermistor element; Defined as the standard reference temperature set by the system, the industrial standard setting is 25℃.

[0088] Considering the operational security of the algorithm logic in extreme environments, and addressing the impact of extreme cold weather in winter... If the value is too low, it may cause the denominator to approach 0 in the division operation, which is a singularity risk. The intelligent main control module has a built-in algorithm protection mechanism. Before performing the division operation, the system independently calculates the denominator term. The absolute value of the value. If the absolute value is determined to be less than the preset first safety minimum value (e.g., 0.001), the intelligent main control module will directly suspend the current calculation, throw a sensor failure exception, and maintain the previous calculation result, thereby avoiding controller crash caused by underlying arithmetic overflow.

[0089] In subsequent steps, the intelligent main control module uses the calculated conductivity value at the standard reference temperature as the basis for water quality judgment. Specifically, the system obtains the conductivity value at the standard reference temperature from the product water probe and performs the aforementioned temperature compensation calculation, and uses it as the real-time product water conductivity value called in subsequent control steps (such as step S4).

[0090] In this embodiment, to address the pipeline pressure loss and high-pressure pump cavitation issues caused by the parallel execution of pretreatment backwash commands and main system water flow requests, the intelligent main control module constructs a priority collaborative control mechanism based on status signal feedback. Step S2 specifically includes the following sub-steps:

[0091] S201, the intelligent main control module synchronously collects multi-source operation request signals within the system to establish the logical benchmark for action execution. To accurately capture the system's hydraulic demands, the system must obtain input parameters from both liquid level and mechanical valve dimensions. In specific operational monitoring, the intelligent main control module acquires a water production process request signal input reflecting the pure water tank's liquid level status. The selection of this signal directly reflects the actual water consumption of the end user.

[0092] Combining the dry contact switch signal obtained in step S1, the intelligent main control module acquires the pretreatment backwash signal. This signal is used as another input parameter because it accurately characterizes whether the pretreatment filter media is at risk of clogging and requires cleaning. Based on the combination of these two independent status signals, the control system sets the hydraulic priority of the pretreatment backwash to the highest level at the software level, using this as the basis for subsequent actuator status allocation instructions.

[0093] For the signal acquisition circuit configuration of the float level switch or static pressure level sensor inside the pure water tank, those skilled in the art can select the appropriate model according to the depth of the water tank and the control accuracy requirements. Conventional level monitoring and digital conversion are well-known technologies in this field and will not be elaborated here.

[0094] S202, after establishing the priority benchmark, the system uses Boolean algebra operations to implement hardware-level signal interlocking. Its general technical principle is to forcibly block low-priority action instructions by using the zeroing characteristic of multiplication operations. The intelligent main control module performs algebraic operations on control variables based on the priority determination result, and then issues hardware drive instructions.

[0095] To achieve targeted allocation of water resources, the control enable state of the high-pressure pump is defined as follows: The inlet solenoid valve is in the open state as follows: The operating mode of the raw water pump is At the same time, the water production process request signal input is defined as... The pre-processing backwash signal is The algebraic logic relationship of the control interlock is described by the following mathematical expression:

[0096] ;

[0097] ;

[0098] ;

[0099] In the formula, This is a Boolean variable. A value of 1 indicates that the system has a water purification process requirement, and a value of 0 indicates that the pure water tank is full. This is a Boolean variable. A value of 1 indicates that the preprocessing module has entered the backwashing state, and a value of 0 indicates that the preprocessing module is not in the cleaning state. and The hardware is enabled when the calculation result is 1, and forced to shut down when the result is 0. When the calculation result is 0, it corresponds to the conventional collaborative mode controlled by the liquid level; when the value is 1, it corresponds to the raw water pump directional supply mode that is forced to maintain operation.

[0100] The final start enable signal of the raw water pump is equal to and The result of a logical OR operation. That is, in the normal cooperative mode ( The raw water pump is directly affected by the liquid level signal. Control; under the targeted supply model ( The raw water pump was forced into operation.

[0101] During the execution of the above-mentioned operational logic, when the pretreatment backwash signal is 0, the operating status of the high-pressure pump and the inlet solenoid valve changes completely in accordance with the water production process request signal input. Once the pretreatment multi-way valve reaches the set cycle and triggers the backwash action, causing the pretreatment backwash signal to be 1, regardless of whether the pure water tank issues a water production process request, the polynomial calculation result in the above formula is immediately set to zero. Based on the calculation result, the intelligent main control module forcibly sets the control enable status of the high-pressure pump and the opening status of the inlet solenoid valve to 0, thereby suspending the current or pending reverse osmosis water production process in the circuit.

[0102] As a preferred approach, considering that transient power outages can easily trigger destructive water hammer effects in closed pipelines, the intelligent main control module introduces a stepped timing difference control when executing the shutdown operations of the high-pressure pump and the inlet solenoid valve. The system controls the high-pressure pump to shut down first, and then, after a 3-5 second delay using an internal timer, sends a coil de-energization command to the inlet solenoid valve. The value of this delay is based on the mechanical inertia coasting time of the high-pressure pump impeller, thereby ensuring the gradual release of residual water pressure inside the pipeline.

[0103] Simultaneously, the raw water pump's operating mode calculation result of 1 causes the system to automatically switch to the raw water pump directional supply mode. At this time, the raw water pump is disconnected from the liquid level control cycle and continues to operate continuously. The full water pressure and rated flow generated by the raw water pump are directionally delivered to the pretreatment module through the upstream pipeline, providing sufficient hydraulic support for backwashing and forward washing of the quartz sand and activated carbon filter media, eliminating the risk of cleaning kinetic energy attenuation caused by the reverse osmosis unit's diversion.

[0104] S203: The system continuously monitors the backwash status during directional water supply and performs a smooth recovery of the working mode after cleaning. When the pretreatment module completes the cleaning process, the multi-way valve cuts off the dry contact signal, causing the pretreatment backwash signal to flip to 0. To prevent the transient electrical signal disconnection generated during the operation of the internal mechanical cam of the multi-way valve from causing frequent state switching of the control system, the intelligent main control module executes state release based on multi-dimensional judgment logic.

[0105] Specifically, when the pretreatment backwash signal flips to 0, the intelligent main control module first deactivates the forced directional supply mode of the raw water pump, allowing the raw water pump to stop and depressurize based on the liquid level signal. Subsequently, the intelligent main control module opens the status release observation window. Only when the pretreatment backwash signal remains at 0 within the continuous time window, and the system pipeline pressure value obtained in step S1 falls back to the preset safe resting range, can the intelligent main control module confirm the completion of the backwashing process. As a preferred method, the length of this continuous time window is set to 10 seconds, based on fully covering the longest time taken for the camshaft of a commercially available conventional multi-way valve to rotate through the mechanical dead zone; and the preset safe resting range is set to 0.1 MPa to 0.2 MPa to confirm that there is no abnormal residual pressure in the pipeline.

[0106] Once the composite judgment condition is met, the system releases its suspended state and reintroduces the water production process request signal from the pure water tank into the control loop. If the system still requires water production at this time, the intelligent main control module will sequentially activate the inlet solenoid valve and the high-pressure pump according to the standard water production process sequence, restoring the conventional reverse osmosis water purification process.

[0107] See attached document Figure 3 In this embodiment, addressing the technical problem of transient pressure fluctuations in commercial municipal water supply networks, which can easily lead to frequent and indiscriminate start-ups and shutdowns of water purification equipment and even damage to high-pressure pumps, the intelligent main control module incorporates a tiered pressure filtering and deadlock protection control architecture. This mechanism aims to accurately distinguish between transient water pressure instability and hard faults, preventing destructive dry running. Step S3 specifically includes the following sub-steps:

[0108] S301, the intelligent main control module establishes high and low pressure anomaly threshold conditions and performs anomaly feature discrimination based on real-time acquired pipeline pressure signals. The general technical principle of this step is to construct a piecewise function in the time domain to transform continuously changing simulated pressure values ​​into discrete Boolean state quantities, which serve as the trigger conditions for the underlying protection action.

[0109] In specific operating conditions, to comprehensively assess the hydraulic safety status of the system, evaluation parameters must be selected from two dimensions: inlet water supply and outlet water flow. Therefore, the intelligent main control module extracts the low-pressure data before the pump and the high-pressure data before the membrane (i.e., the inlet pipeline pressure data measured by the low-pressure detection element and the outlet pipeline pressure data measured by the high-pressure detection element) obtained in step S1. The low-pressure data before the pump accurately reflects the water supply margin of the municipal pipe network, while the high-pressure data before the membrane characterizes the water flow resistance of the reverse osmosis membrane module and the flow condition of the downstream pipeline. Considering the time difference in analog signal acquisition, the intelligent main control module synchronously latches the two pressure data streams using the same clock cycle within its internal PLC scanning cycle, ensuring that the data frames participating in the comparison are completely aligned in the time domain, avoiding misjudgments of operating conditions due to asynchronous reading. The abnormal characteristic function of the pipeline pressure status is described by the following mathematical expression:

[0110] ;

[0111] In the formula, Defined as a characteristic function of abnormal pipeline pressure; Defined as the low pressure before the pump that is detected in real time; Defined as a preset low-voltage threshold; Defined as the membrane inlet high voltage that is detected in real time; Defined as a preset high-voltage threshold; For conditional triggering; For Boolean logic, it includes the OR operator, specifically meaning: when the condition is met... Establishment, or determination conditions The logical relationship is determined to be valid when either condition is met, or when both of the above conditions are met simultaneously. This indicates that if the above conditions are not met... All other cases involving the logical conditions.

[0112] As a preferred approach, the preset low-pressure threshold is set within the range of 0.03MPa to 0.05MPa, determined based on the minimum suction head required for the multi-stage centrifugal high-pressure pump to overcome cavitation. The preset high-pressure threshold is set within the range of 1.2MPa to 1.5MPa, based on the lower limit of the design burst pressure safety limit for the fiberglass shell of the reverse osmosis membrane module. To avoid biased judgments due to a single extreme value, the system introduces multi-cycle weighted filtering logic; that is, the judgment only takes effect when the pressure values ​​in three consecutive sampling cycles exceed the limit. The system performs high-frequency polling calculations during the water production process. Once the calculation result indicates that the pipeline pressure anomaly characteristic function is 1, the intelligent main control module immediately issues an emergency cut-off command, disconnecting the power supply circuit of the high-pressure pump, thereby preventing the equipment from operating under harsh hydraulic conditions.

[0113] S302, based on the above anomaly detection, the intelligent main control module introduces a time-dimension delay intervention to execute transient pressure filtering and the initial trial start-up procedure. The general technical principle of this step is to use a delay timer to construct a condensation period, filtering out transient water hammer interference caused by water pumping or rapid opening and closing of valves during peak water usage periods in the pipeline network.

[0114] After the intelligent main control module shuts off the high-pressure pump, it automatically activates the internally set condensation delay timer. As a preferred method, the condensation delay time (i.e., the set delay value) is set to 60-90 seconds. This delay parameter is selected based on the average time span required for the network pressure to dynamically recover when the municipal secondary water supply equipment switches to the variable frequency pump set. During the condensation period, the intelligent main control module forcibly suspends all regular water production process requests, maintaining the core actuator in a dormant state.

[0115] After the delay timer resets to zero, the intelligent main control module drives the high-pressure pump to perform the initial test start-up and opens a brief pressure build-up observation window. In this embodiment, the duration of this pressure build-up observation window is strictly set to 5s to 8s. This parameter range perfectly matches the time taken for the multi-stage centrifugal water pump to build up its mechanical characteristic curve from a standstill to full load head. If the real-time pressure data returns to normal within this window, causing the pipeline pressure anomaly characteristic function to return to 0, the intelligent main control module determines that the previous pressure loss or overpressure was only an occasional, instantaneous fluctuation in the pipeline network. The system then automatically clears the abnormal alarm records, seamlessly switches back to the conventional reverse osmosis water production process, and simultaneously resets the cumulative number of consecutive test start-up failures recorded internally to zero, ensuring the initial completeness of the algorithm logic when entering the next cycle.

[0116] S303: As the trial procedure is executed, in response to serious faults such as valve blockage or municipal water outages in the pipeline, the system initiates a limited-number trial algorithm and self-locking protection logic. The technical purpose of this control logic is to prevent the hardware from entering a destructive infinite loop and restarting under irreversible faults by counting the number of consecutive trial and error attempts.

[0117] The specific logic for determining the system's operational safety status is described by the following mathematical expression:

[0118] ;

[0119] In the formula, Defined as a lock flag; Defined as the cumulative number of consecutive failed start-up attempts within a statistical window of a complete water production process cycle; Defined as the set upper limit threshold for failed start-ups; This indicates that if the following conditions are met.

[0120] In this embodiment, the upper limit threshold for failed test starts is preferably set to 3 times. This specific value is determined based on an engineering balance between the probability of self-healing recovery of the pipeline pressure and the cumulative risk of thermal damage to the pump bearings caused by repeated dry runs. If the initial test start and subsequent cyclic tests fail to restore the pressure to a safe range, the cumulative number of consecutive failed test starts increases. Once this number reaches or exceeds the set upper limit threshold for failed test starts, the calculation result of the locking flag immediately flips to 1.

[0121] At this point, the control system determines that the pipeline network has encountered a hard fault, and the intelligent main control module immediately enters a system lockout state. At this safety level, the intelligent main control module cuts off the power output to all water pump components and simultaneously triggers an audible and visual lockout alarm on the human-machine interface. The underlying control program will forcibly block any automatic restart actions based on liquid level or timing signals. To ensure a safe closed-loop maintenance process, the lockout state requires maintenance personnel to arrive on-site to troubleshoot the hardware fault and issue a privilege unlock command via the control panel or execute a power-off hard restart to forcibly reset the cumulative number of failed start-ups to zero. Only after receiving a manual intervention command will the system release the lockout flag, allowing the equipment to regain automatic operation privileges.

[0122] See attached document Figure 4 In this embodiment, to address the natural ion permeation phenomenon caused by concentration differences during the shutdown and standby phase of the reverse osmosis equipment, as well as the water quality deterioration caused by prolonged stagnant water, the intelligent main control module constructs a dynamic quality preservation control closed loop with dual-path conductivity linkage. Step S4 specifically includes the following sub-steps:

[0123] S401, the intelligent main control module executes the anti-deterioration flushing logic based on an internal sleep timer. The general technical principle of this step is to break the static concentration polarization layer inside the membrane element through low-pressure, high-flow-rate hydraulic displacement. When the equipment finishes its water production process and enters standby monitoring mode, the osmotic pressure inevitably reverses across the reverse osmosis membrane due to the disappearance of the hydraulic driving pressure. The intelligent main control module starts the sleep timer, and when the accumulated standby time reaches the preset sleep duration limit (i.e., the set standby interval), the system determines that the water quality inside the membrane chamber has undergone irreversible natural osmotic deterioration. As a preferred method, the preset sleep duration limit is adjustable from 1h to 24h, determined based on the Brownian diffusion rate limit of hydrated ions at room temperature.

[0124] Based on the aforementioned time cycle determination, the intelligent main control module simultaneously activates the raw water pump, inlet solenoid valve, and flushing solenoid valve, but does not start the high-pressure pump. Raw water flows rapidly through the reverse osmosis membrane module in a low-pressure, high-flow-rate mode, forcibly draining the high-concentration-gradient retained concentrate from the membrane chamber, thereby inhibiting internal bacterial growth. After completing the set flushing time, the system resets the sleep timer and re-enters standby monitoring mode.

[0125] In S402, during the initial stage when the equipment receives a water production process request and is activated, the intelligent main control module performs dynamic interception control of the first cup of water. The technical purpose of this control is to cut off the path for abnormal water to enter the downstream water storage system before the water quality desalination rate stabilizes. The intelligent main control module opens the inlet solenoid valve and starts the high-pressure pump to carry out the water production process, and issues a combination of commands to the actuators. In specific implementation, the system forcibly closes the product water inlet solenoid valve and simultaneously opens the bypass discharge solenoid valve. The first cup of water produced by the reverse osmosis membrane module is directly discharged into the wastewater recovery pipeline through the bypass pipeline.

[0126] During this period, the intelligent main control module frequently calls the temperature-compensated permeate conductivity data obtained in step S1 as the core input parameter for subsequent water quality determination: the real-time permeate conductivity value.

[0127] The S403 intelligent main control module performs a two-dimensional joint calculation of the conditions for releasing water into the container based on real-time data. To achieve accurate determination of 100% water quality safety, the system introduces the first-order rate of change of the real-time conductivity value of the produced water in the time domain as a weighted judgment criterion to comprehensively evaluate the stability of the water quality status.

[0128] The joint decision function for allowing container entry is described by the following mathematical expression:

[0129] ;

[0130] In the formula, Defined as the result of the joint determination function for permeate inlet tank; Defined as the real-time conductivity value of the produced water; Defined as a preset threshold (i.e., alarm limit); Defined as the conductivity value of the produced water in the previous sampling period; Defined as a preset discrete sampling time interval; Defined as a preset threshold for the rate of change of conductivity; For conditional triggering; For Boolean logic AND operator, specifically, it means that its preconditions (i.e., ...) must be met simultaneously. This indicates that if the above conditions are not met... All other cases involving the logical conditions.

[0131] Considering that the judgment logic involves division and derivative operations, the system must ensure the validity of the divisor to prevent the underlying software from crashing under extreme abnormal conditions. For example, when a clock synchronization module malfunctions, causing two sampling timestamps to overlap, the time difference is very likely to approach zero. To address this risk, the intelligent main control module is configured with mandatory verification logic before executing the division instruction. The system independently extracts the time interval between two sampling points for absolute value judgment. When the value of the time interval is determined to be less than the preset second safety minimum value (e.g., 0.01s), the derivative operation is directly suspended, the calculation result of the previous cycle is maintained, and a clock synchronization abnormality flag is thrown to the system log. Under normal stable operating conditions, based on the underlying hardware timer interrupt mechanism, the preset discrete sampling time interval is strictly guaranteed to be a constant non-zero constant. As a preferred method, this discrete sampling time interval is set to 1s to 2s to filter out data spikes caused by high-frequency acquisition and ensure that the operating conditions of multi-source operation data are aligned on the time axis.

[0132] Regarding the criteria for determining the various judgment thresholds, in this embodiment, the preset threshold for achieving the standard conductivity of the permeate is typically set below 50 μS / cm, and its specific value strictly adheres to the drinking water quality standards of the country or region. The preset threshold for the stability of conductivity change rate is preferably set to 2–5 μS / (cm·s). This parameter signifies that the osmotic pressure build-up process inside the membrane module has stabilized, and the permeate desalination rate no longer undergoes a step-like change.

[0133] In actual logic execution, when the real-time conductivity value of the produced water... Greater than the preset threshold At this time, the system forcibly locks the permeate inlet solenoid valve while maintaining the bypass discharge solenoid valve open; only when continuous calculations confirm... Furthermore, the water quality change rate satisfies the stationary condition, leading to the result of the judgment function. When the value is 1, the intelligent main control module confirms that the produced water quality has entered a safe steady state. Immediately, the control layer outputs a reverse command, closing the bypass discharge solenoid valve and simultaneously opening the produced water inlet solenoid valve. Qualified purified water is then officially injected into the pure water tank. During the subsequent water production process, the system continuously monitors the above indicators. When the liquid level sensor inside the pure water tank triggers a full water feedback signal, the intelligent main control module terminates the current workflow, cuts off the water pump power, completes this water production cycle, and seamlessly transitions to a new standby monitoring state.

Claims

1. A method for intelligent linkage control of a multi-stage reverse osmosis water purification system, characterized in that, Includes the following steps: Real-time acquisition of multi-way valve dry contact signals, pipeline pressure signals, and water quality parameters, and acquisition of the real-time conductivity value and the rate of change of conductivity of the produced water from the water quality parameters; When the signal of the dry contact of the multi-way valve is determined to be closed, the current water production process is interrupted and the raw water pump is controlled to supply the output water to the pretreatment module; after the signal of the dry contact of the multi-way valve is switched to open, the normal water production process is restored. When the pipeline pressure signal is determined to be abnormally high-pressure, the power supply to the high-pressure pump is cut off and a test start action is performed, and the cumulative number of consecutive test start failures is counted. If the cumulative number of consecutive failed start attempts reaches the set upper limit threshold for failed start attempts, the power output of the entire machine will be cut off and the operating status will be locked. When the water production process is started, the real-time conductivity value of the produced water is compared with the preset threshold, and the action of the bypass discharge solenoid valve and the produced water inlet solenoid valve is controlled according to the comparison result. When the real-time conductivity value of the produced water is higher than the preset threshold, bypass discharge is performed; when the real-time conductivity value of the produced water is not higher than the preset threshold and the rate of change of the produced water conductivity meets the stable condition, the produced water is fed into the tank.

2. The intelligent linkage control method for a multi-stage reverse osmosis water purification device according to claim 1, characterized in that, The steps of real-time acquisition of multi-way valve dry contact signals, pipeline pressure signals, and water quality parameters include, specifically, the acquisition of the water quality parameters: Continuously read dual-channel conductivity data and real-time water temperature data from the inlet and outlet of the reverse osmosis membrane module; The original conductivity data and the real-time water temperature data are time-frame aligned based on the sampling timestamp of the internal clock. The temperature compensation calculation process, which involves division, is performed based on thermodynamic properties. Before performing the division operation, the absolute value of the denominator term of the division operation is calculated independently. When it is determined that the absolute value of the denominator is less than the preset first safety minimum, the previous calculation result is maintained, and the preset first safety minimum is set to 0.001; When it is determined that the absolute value of the denominator is not less than the preset first safety minimum value, the temperature compensation calculation process is executed to convert the original conductivity data at different ambient temperatures into conductivity calculation values ​​at the standard reference temperature.

3. The intelligent linkage control method for a multi-stage reverse osmosis water purification device according to claim 1, characterized in that, The steps of interrupting the current water production process and controlling the raw water pump to supply the output water to the pretreatment module specifically include: Simultaneously collect the water production process request signal input of the pure water tank liquid level status and the pretreatment backwash signal; Using Boolean algebra operations, hardware-level signal interlocking is implemented, setting the control enable state of the high-pressure pump and the opening state of the water inlet solenoid valve in the pipeline to 0. The high-pressure pump is powered off and stopped, and an internal timer is invoked to delay before a coil power-off command is sent to the water inlet solenoid valve. The raw water pump is controlled to disengage from the liquid level control cycle and continuously maintain the start-up and operation state; When the pretreatment backwash signal flips to 0, and the pretreatment backwash signal remains at 0 within a continuous time window while the pressure value of the pipeline pressure signal falls back to the safe resting range, the safe resting range is set to 0.1MPa~0.2MPa. The water production process request signal is then reintroduced into the control loop, and the inlet solenoid valve and the high-pressure pump are turned on.

4. The intelligent linkage control method for a multi-stage reverse osmosis water purification device according to claim 1, characterized in that, When the pipeline pressure signal is determined to be abnormally high, the steps of cutting off the high-pressure pump power supply, performing a test start, and counting the cumulative number of consecutive failed test starts specifically include: Extract the low-pressure data before the pump and the high-pressure data before the membrane, and perform synchronous latching of the two pressure data using the same clock cycle; A piecewise function in the time domain is constructed to transform continuously changing simulated pressure values ​​into discrete Boolean state variables; When the low pressure data before the pump is determined to be lower than the preset low pressure threshold, or the high pressure data before the membrane is higher than the preset high pressure threshold, and the pressure values ​​of three consecutive sampling cycles exceed the limit, the abnormal result is determined to be effective, and an emergency cut-off command is issued to disconnect the power supply circuit of the high pressure pump. The internally set condensation delay timer is activated to start the delay timer, suspending all regular water production process requests during the condensation period; After the delay timer expires, the high-pressure pump is controlled to start for trial operation, and the pressure building observation window is opened. When the pressure data in the pressure building observation window returns to normal, the abnormal alarm record is cleared, and the cumulative number of consecutive failed trial starts recorded internally is simultaneously cleared to zero.

5. The intelligent linkage control method for a multi-stage reverse osmosis water purification device according to claim 1, characterized in that, The steps for disconnecting the power output of the entire machine and locking the operating status specifically include: The system counts the cumulative number of consecutive failed test starts. When the cumulative number of consecutive failed test starts reaches the set upper limit threshold for test start failure, the system enters a self-locking state, cuts off the power output of all water pump components, triggers an audible and visual locking alarm on the human-machine interface, and blocks any automatic restart action based on liquid level or timing signals. The set upper limit threshold for test start failure is set to 3 times. Upon receiving a manual intervention instruction, the cumulative number of consecutive failed startup attempts is reset to zero, and the automatic operation permission is regained.

6. The intelligent linkage control method for a multi-stage reverse osmosis water purification device according to claim 1, characterized in that, Before starting the water production process, the following is also included: When the equipment finishes its water production process and enters standby monitoring mode, a sleep timer is started. When the accumulated standby time reaches the preset sleep duration limit, the raw water pump, inlet solenoid valve, and flushing solenoid valve are opened simultaneously, but the high-pressure pump is not started. The preset sleep duration limit is set to 1h to 24h. The raw water is controlled to flow through the reverse osmosis membrane module. After the set flushing time is completed, the sleep timer is reset and the system is switched back to the standby monitoring state.

7. The intelligent linkage control method for a multi-stage reverse osmosis water purification device according to claim 1, characterized in that, The steps for real-time acquisition of multi-way valve dry contact signals, pipeline pressure signals, and water quality parameters also include: The absolute value of the time interval between two sampling points is extracted independently. When the value of the time interval is determined to be less than the preset second safety minimum, the calculation result of the previous cycle is maintained and a clock synchronization abnormality flag is thrown. The preset second safety minimum is set to 0.01s.

8. The intelligent linkage control method for a multi-stage reverse osmosis water purification device according to claim 4, characterized in that, The preset low-pressure threshold is set in the range of 0.03MPa to 0.05MPa, and the preset high-pressure threshold is set in the range of 1.2MPa to 1.5MPa.

9. The intelligent linkage control method for a multi-stage reverse osmosis water purification device according to claim 1, characterized in that, In the step of obtaining the real-time conductivity value of the product water and the rate of change of the product water conductivity in the water quality parameters, specifically, the first-order rate of change of the real-time conductivity value of the product water is obtained as the rate of change of the product water conductivity. The preset threshold for achieving the target is set to be below 50 μS / cm; The rate of change of conductivity of the produced water meets the stability condition, specifically meaning that the first-order rate of change is less than or equal to a preset stability threshold for conductivity rate of change, which is set to 2-5 μS / (cm·s).

10. An intelligent linkage control system for a multi-stage reverse osmosis water purification device, characterized in that, The intelligent linkage control system, which is applied to any one of claims 1-9, comprises: a raw water supply module, a pretreatment module, a main water-making module, and an intelligent main control module. The raw water supply module includes a raw water tank and a raw water pump, with the output end of the raw water tank connected to the inlet end of the raw water pump; The pretreatment module includes a multi-way valve and a quartz sand filter and an activated carbon filter controlled by the multi-way valve. The multi-way valve has a dry contact signal output port. The main water-making module includes a security filter, an inlet solenoid valve, a high-pressure pump, a reverse osmosis membrane module, and a pure water tank. The product water end pipeline of the reverse osmosis membrane module is divided into two lines, with a product water inlet solenoid valve and a bypass discharge solenoid valve installed respectively. The outlet end of the product water inlet solenoid valve is connected to the pure water tank. A flushing solenoid valve is installed on the concentrate end pipeline of the reverse osmosis membrane module. The main water-making module includes multiple sets of detection elements, including a conductivity probe connected to a dual-channel conductivity sensor transmitter, a low-pressure detection element, and a high-pressure detection element. The signal input port of the intelligent main control module is connected to the dry contact signal output port, the dual-channel conductivity sensor transmitter, the low-pressure detection element, the high-pressure detection element, and the liquid level sensor, respectively. The control output port of the intelligent main control module is connected to the raw water pump, the inlet solenoid valve, the flushing solenoid valve, the high-pressure pump, the product water inlet solenoid valve, and the bypass discharge solenoid valve, respectively.

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