A high-pressure constant flow pump and its control method

Abstract

This invention relates to the field of fluid control technology, specifically to a flow calibration method for a high-pressure constant flow pump and the high-pressure constant flow pump itself. The control method includes the following steps: receiving a control command and obtaining a target flow rate value and a pressure safety threshold range; calculating the initial theoretical speed of the motor based on the target flow rate value and driving the motor to run; obtaining the real-time speed of the motor based on the flow detection module and the real-time output pressure value of the high-pressure constant flow pump based on the pressure detection module; determining whether the real-time output pressure value exceeds the pressure safety threshold range; if so, controlling the motor to perform a safety protection action; if not, calculating the actual output flow rate value based on the real-time speed; determining the flow ratio coefficient based on the ratio of the actual output flow rate value to the target flow rate value; calculating the target speed of the motor based on the target flow rate value and the flow ratio coefficient; and adjusting the motor to the target speed to achieve more precise flow control.

Description

Technical Field

[0001] This invention relates to the field of fluid control technology, specifically to a flow calibration method for a high-pressure constant flow pump and the high-pressure constant flow pump itself. Background Technology

[0002] High-pressure constant flow pumps are key components in chromatography systems, precision drug delivery equipment, and other fields. Their performance directly determines the reliability and accuracy of the analytical results of the entire system. The core requirement for this type of pump is the ability to output a constant flow rate with high precision and high stability under high pressure.

[0003] In existing technologies, plunger pumps are commonly used, and constant flow is achieved by controlling the motor speed. To eliminate the inherent flow pulsation of a single plunger pump, multi-pump cooperative operation is a common technical approach. For example, Chinese Patent No. CN217002190U discloses a multi-pump cooperative control system for a high-pressure constant flow pump. This system uses multiple plunger pumps, each with its own drive motor, and controls the alternating operation of the multiple pump heads via a microcomputer. Simultaneously, a pressure sensor installed on the outlet pipeline monitors the system pressure, and based on this pressure feedback, the switching points of each pump motor are adjusted in real time to compensate for pressure and flow fluctuations at the switching moments, thereby improving output stability to a certain extent.

[0004] However, this existing technical solution still has the following limitations, especially in terms of maintaining accuracy and facilitating calibration over long-term operation:

[0005] 1. This system indirectly infers and stabilizes flow rate by monitoring pressure changes at the output end, but this indirect control method is not fast enough. When changes in pipeline resistance, fluid viscosity, etc., cause pressure fluctuations, the flow rate may have already deviated, which limits further improvement in the system's flow control accuracy.

[0006] 2. This control system does not measure and provide feedback on the actual speed of the motor driving the pump head in real time, therefore it cannot ensure that the motor always operates strictly at the set speed. The motor is prone to speed drift due to factors such as load changes, power fluctuations, or mechanical transmission clearances, which directly affects the instantaneous accuracy of the output flow.

[0007] 3. After long-term operation, factors such as plunger seal wear and changes in fluid viscosity can lead to unavoidable systematic deviations between the actual pump output flow and the expected value calculated based on the theoretical speed. The existing technology represented by CN217002190U cannot easily eliminate this accuracy degradation caused by long-term operation. It typically requires manual intervention or hardware adjustments for correction, and cannot provide a rapid online calibration function for the user. This severely impacts the long-term accuracy retention and ease of use and maintenance of the equipment.

[0008] Even if the motor runs at the theoretical speed, the actual output flow may deviate from the preset value. Summary of the Invention

[0009] This invention provides a high-pressure constant flow pump and its control method to solve the technical problem that the actual output flow of existing high-pressure constant flow pumps cannot be corrected quickly and with high precision.

[0010] To solve the above problems, the present invention adopts the following technical solution:

[0011] On one hand, the present invention provides a control method for a high-pressure constant flow pump, the high-pressure constant flow pump including a motor, a flow detection module, a pressure detection module, and a control module, the control method including the following steps:

[0012] Receive control commands and obtain target flow rate and pressure safety threshold range;

[0013] Based on the target flow rate, the initial theoretical speed of the motor is calculated, and the motor is driven to run.

[0014] The real-time speed of the motor is obtained based on the flow detection module, and the real-time output pressure value of the high-pressure constant flow pump is obtained based on the pressure detection module.

[0015] Determine whether the real-time output pressure value exceeds the pressure safety threshold range;

[0016] If so, then control the motor to perform safety protection actions;

[0017] If not, proceed with the following steps:

[0018] The actual output flow rate of the high-pressure constant flow pump is calculated based on the real-time rotation speed.

[0019] The flow ratio coefficient is determined based on the ratio of the actual output flow value to the target flow value.

[0020] The target speed of the motor is calculated based on the target flow rate value and the flow rate ratio coefficient.

[0021] Adjust the motor to the target speed.

[0022] This invention achieves direct, online, and adaptive calibration of pump output flow by introducing a flow proportionality coefficient as the core calibration variable. This method can directly detect and compensate for systematic flow deviations caused by mechanical wear, changes in fluid characteristics, and component aging. This calibration mechanism based on real flow feedback fundamentally solves the problem of long-term operational accuracy degradation caused by existing technologies that rely on indirect parameters (such as pressure) or open-loop control, ensuring that the high-pressure constant flow pump maintains extremely high output accuracy throughout its entire lifespan.

[0023] The flow proportional coefficient, as a dynamic parameter, can be determined and updated in real time based on the system state. This enables the control system to adaptively respond to flow changes under different operating conditions (such as different fluid viscosities and different back pressures). By incorporating this coefficient into the calculation of the target speed, precise, feedforward correction of the motor speed is achieved, allowing the system to recover stability more quickly when faced with internal and external disturbances, thus obtaining superior dynamic performance and steady-state accuracy compared to traditional single feedback control.

[0024] Compared to the prior art's method of indirectly inferring flow rate through pressure feedback, this invention directly uses flow rate as the core control and calibration object, eliminating the delay and error caused by intermediate conversion links. This calibration strategy, which directly targets the controlled variable (flow rate), has a faster response and a simpler and more efficient control loop, fundamentally improving the accuracy of flow control.

[0025] As a preferred embodiment of the present invention, the flow detection module includes an encoder and an optocoupler, and the actual output flow value is indirectly calculated by detecting the rotational speed of the encoder.

[0026] By employing a non-contact detection scheme consisting of a code disk and an optocoupler, the risks of contamination, corrosion, pressure loss, and leakage that may arise from direct contact with fluid in traditional flow sensors are effectively avoided. This scheme indirectly calculates flow rate by detecting the rotational speed of the drive shaft at high frequency, resulting in an extremely fast response speed. It can capture instantaneous flow fluctuations, providing highly timely and reliable raw data for subsequent calculations of the flow ratio coefficient, fundamentally ensuring the accuracy and reliability of the entire calibration method.

[0027] As a preferred technical solution of the present invention, after adjusting the speed of the motor, the process returns to the step of "obtaining the real-time speed of the motor based on the flow detection module" to form closed-loop control.

[0028] By constructing the control flow as a closed loop that returns to obtain real-time rotational speed, this invention is no longer a one-time calibration, but an intelligent process of continuous monitoring and dynamic adjustment. This closed loop has the following functions:

[0029] 1. Real-time compensation for instantaneous disturbances: The system can detect and quickly correct instantaneous deviations in rotational speed caused by voltage fluctuations, load changes, or fluid pulsation, preventing them from accumulating into significant flow errors.

[0030] 2. Tracking and correcting systematic drift: This closed-loop system can continuously and automatically make fine adjustments to address the systematic accuracy decay caused by slow-changing factors such as temperature rise during long-term operation of the equipment and minor wear of mechanical parts, so that the flow ratio coefficient and motor speed are always kept in the optimal state, thereby greatly improving the long-term accuracy retention of the equipment throughout its entire life cycle.

[0031] 3. Forming a dynamic equilibrium: Through closed-loop feedback, the system continuously compares and corrects the actual state with the target state, ultimately enabling the output flow to reach a dynamic and highly stable equilibrium state around the target value, achieving steady-state accuracy that surpasses open-loop or feedforward control.

[0032] In summary, this invention provides a high-pressure constant flow pump control method that enables more direct, faster, and more precise flow control and has online calibration capabilities.

[0033] As a preferred embodiment of the present invention, the step of "indirectly calculating the actual output flow rate value by detecting the rotational speed of the encoder" specifically includes:

[0034] Receives the pulse signal generated by the optocoupler when the code disk rotates;

[0035] Calculate the time interval between two consecutive pulse signals;

[0036] Based on the time interval and the physical structure parameters of the encoder, the real-time speed of the motor is calculated.

[0037] The actual output flow rate is calculated based on the correspondence between the real-time speed of the motor and the pump displacement.

[0038] As a preferred embodiment of the present invention, the step of "calculating the target speed of the motor based on the target flow rate value and the flow rate ratio coefficient" specifically involves multiplying the theoretical speed of the motor calculated based on the target flow rate value by the flow rate ratio coefficient to obtain the corrected target speed.

[0039] As a preferred embodiment of the present invention, in the closed-loop control, the speed of the motor is dynamically adjusted by a PID control algorithm based on the deviation between the actual output flow rate and the target flow rate.

[0040] By introducing a PID (proportional-integral-derivative) control algorithm, the system can intelligently handle flow deviations and achieve high-quality control results.

[0041] Proportional (P) control: responds instantly and proportionally to current flow deviations, ensuring the system has a fast dynamic response speed and can quickly correct flow fluctuations.

[0042] Integral (I) control: By continuously accumulating historical deviations, it can completely eliminate steady-state error. This means that even with small, continuous disturbances (such as minute internal leakage), the system can automatically adjust through integral action, ultimately stabilizing the actual output flow rate precisely at the target value, achieving ultra-high precision constant current output.

[0043] Derivative (D) control: This system proactively adjusts based on the rate of change of the deviation, effectively suppressing overshoot and smoothing the system response. This results in smoother motor speed adjustment, avoiding drastic speed fluctuations and further reducing output flow pulsation.

[0044] By combining mature PID control theory with the unique flow proportional coefficient calibration method of this invention, a perfect combination of "coarse adjustment" and "fine adjustment" is achieved. The flow proportional coefficient is responsible for macroscopic calibration (coarse adjustment) of systematic, long-term deviations, while the PID controller is responsible for fine adjustment (fine adjustment) of instantaneous, dynamic deviations. This combination enables the entire control system to have a higher level of intelligence, automatically maintaining the optimal control state under various operating conditions without frequent manual intervention.

[0045] As a preferred embodiment of the present invention, the control method further includes a maintenance early warning step:

[0046] The total operating time or total output flow of the high-pressure constant flow pump is accumulated.

[0047] The accumulated value is compared with a preset threshold, and a maintenance prompt message is generated when the threshold is exceeded.

[0048] By accumulating operating time or total output flow and applying threshold judgments, the equipment maintenance mode is upgraded from the traditional "post-failure repair" or fixed "periodic maintenance" to "predictive maintenance" based on actual workload. This function can proactively remind users before component performance reaches a critical point of degradation, avoiding unplanned downtime and production losses caused by sudden component failure. It also prevents continued operation in a degraded state, which would produce unqualified results, thus ensuring the long-term operational accuracy and service life of the equipment.

[0049] As a preferred embodiment of the present invention, the high-pressure constant flow pump is a dual-plunger pump. The motor drives the two plungers to move alternately via a camshaft, thereby achieving continuous output and stable pressure in the liquid circuit. By employing a dual-plunger pump structure and driving the alternating motion via a camshaft, the discharge stroke of one plunger can seamlessly compensate for the suction stroke of the other plunger, significantly reducing the inherent flow and pressure pulsations of a single-plunger pump from a mechanical perspective.

[0050] As a preferred embodiment of the present invention, the high-pressure constant current pump further includes a camshaft, the code disk is fixedly disposed at one end of the camshaft and rotates synchronously with the camshaft, and a light-transmitting hole is provided on its circumference; the optocoupler is fixedly installed, and its transmitting end and receiving end are respectively located on both sides of the code disk and correspond to the position of the light-transmitting hole.

[0051] On the other hand, the present invention also provides a high-pressure constant flow pump, comprising:

[0052] Electric motor;

[0053] The flow detection module is used to detect the output flow of the high-pressure constant flow pump in real time;

[0054] The pressure detection module is used to detect the pressure of the output fluid circuit in real time.

[0055] The control module is used to execute the control methods described above.

[0056] The beneficial effects are:

[0057] This invention proposes a convenient method for high-precision flow rate calibration without disassembling hardware. By introducing a closed-loop adjustment mechanism that dynamically generates a flow rate proportionality coefficient based on the ratio of actual flow rate to target flow rate, and accordingly correcting the target speed of the stepper motor in real time, the flow control performance of the system under complex operating conditions is significantly improved. This overcomes the limitations of traditional high-pressure constant flow pumps that rely on fixed parameter models, achieving high-precision, highly adaptive, and easily maintainable constant flow output. This solution not only effectively solves the flow drift problem caused by component aging, medium changes, or operating condition fluctuations, but also significantly improves the system's intelligence level and user experience. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the structure of a high-pressure constant flow pump according to the present invention;

[0059] Figure 2 This is a flowchart of a control method for a high-pressure constant current pump according to the present invention.

[0060] Explanation of reference numerals in the attached figures:

[0061] 1. Encoder; 2. Optical coupler; 3. Camshaft; 4. Motor; 5. Plunger. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0063] The number of any elements in the accompanying drawings is for illustrative purposes only and not as a limitation, and any naming is for distinction only and has no limiting meaning.

[0064] The principles and essence of the present invention will be explained in detail below with reference to several representative embodiments.

[0065] This invention provides a high-pressure constant current pump and its control method. The invention will be described in detail below with reference to the accompanying drawings and specific operating procedures.

[0066] like Figure 1 The high-pressure constant flow pump shown includes a dual-plunger module, a drive module, a detection module, and a control module. The drive module is mechanically connected to the dual-plunger module and drives it to work. The detection module is used to collect the operating status of the dual-plunger module and the physical parameters of the output fluid path. The control module is electrically connected to both the drive module and the detection module and is used to control the operation of the drive module based on the feedback from the detection module.

[0067] The dual-plunger module includes pump head A and pump head B arranged side-by-side. The liquid connection is as follows: liquid first enters pump head A, is compressed by it, flows into pump head B, and is finally continuously output from pump head B through an outlet pipe. This alternating operation of the two pump heads aims to eliminate the inherent flow pulsation of a single-plunger pump, achieving continuous flow and stable flow (when one plunger is in the discharge state, the other is in the suction state; the suctioned liquid replenishes the liquid flow that pauses when the other plunger is in the discharge phase, achieving continuous liquid output. This alternating operation of the two plungers ensures the continuity of liquid flow within the circuit, maintaining constant pressure and achieving constant flow in the equipment).

[0068] The dual-plunger module also includes plunger 5 and a seal. Plunger 5 is a high-precision special ceramic plunger; the seal is a corrosion-resistant and wear-resistant seal. This configuration enables the high-pressure constant flow pump to withstand a variety of chemical reagents and operate stably under long-term, high-frequency conditions.

[0069] The drive module includes a motor 4, a timing belt assembly, and a camshaft 3. In this embodiment, a precisely controllable stepper motor is selected as the drive mechanism for the motor 4.

[0070] The driving pulley of the synchronous belt assembly is fixedly connected to the output shaft of the motor 4, and the driven pulley is fixedly connected to the camshaft 3. When the motor 4 is running, it drives the camshaft 3 to rotate through the synchronous belt assembly. The camshaft 3 is configured to drive the plungers 5 of pump head A and pump head B to reciprocate alternately, so that when one pump head is in the discharge stroke, the other pump head is in the suction stroke, thereby ensuring the continuity of the output liquid flow.

[0071] The detection module includes a pressure detection module and a flow detection module. In this embodiment, the pressure detection module includes a pressure transmitter; the flow detection module includes a code disk 1 and an optocoupler 2.

[0072] The pressure transmitter is installed in the liquid outlet line to detect pressure changes inside the liquid line in real time.

[0073] The code disk 1 is fixedly mounted on one end of the camshaft 3 and rotates synchronously with the camshaft 3; a light-transmitting hole is provided on the circumference of the code disk 1. The optocoupler 2 is fixedly installed, with its transmitting end and receiving end located on both sides of the code disk 1, corresponding to the positions of the light-transmitting hole on the code disk 1.

[0074] The detection module and the control module are connected for communication.

[0075] The main control MCU chip of the control module uses a high-performance ARM Cortex-M3 core microcontroller manufactured by STMicroelectronics, which features stable and reliable performance, ultra-low power consumption, and large memory. The control module can store large software programs, facilitating the development of software for different devices to implement complex functions. The control module allows for IAP software upgrades, enabling customers to easily upgrade and maintain the equipment during use, and providing a maintenance solution for resolving specific needs in the future using upgraded software.

[0076] The control module receives and processes signals from the detection module to achieve precise control of the high-pressure constant flow pump, specifically including:

[0077] Flow stability control: The control module detects the pulse signal generated when the encoder 1 rotates via optocoupler 2. By calculating the time interval between two consecutive pulses, the instantaneous rotational speed of encoder 1 (i.e., camshaft 3) can be accurately calculated. This rotational speed has a definite correspondence with the rotational speed of motor 4. The control module compares this measured rotational speed with the preset target rotational speed and dynamically adjusts the operation of motor 4 through control algorithms such as PID, thereby forming a closed-loop control to ensure the stability of motor 4's rotational speed and ultimately guarantee high stability of the output flow.

[0078] Pressure safety monitoring: The control component reads the pressure value detected by the pressure transmitter in real time. The control module has a preset pressure safety threshold range; when the read pressure value exceeds this threshold range, the control module immediately executes protection actions, such as stopping motor 4 and triggering an alarm indication, thereby ensuring that the high-pressure constant flow pump operates safely and reliably within the allowable pressure range.

[0079] Maintenance warning: The control module is equipped with an EEPROM storage chip to store the cumulative running time and flow rate data of the high-pressure constant flow pump. This data is used to determine the wear and tear of the high-pressure constant flow pump during operation. The total running time and total running flow rate preset by the control module are compared with the cumulative running time and flow rate data of the high-pressure constant flow pump stored in the storage chip. If the preset values ​​are reached, the system will send a return command and status indicator light to prompt the customer that the equipment needs to be maintained.

[0080] Specifically, each time the high-pressure constant flow pump starts, the control module records the running time and accumulates the liquid volume flowing through the liquid path using an algorithm. The control module presets the maximum running time and the maximum cumulative running volume. After multiple runs and long-term accumulation, the software automatically determines whether the preset values ​​have been reached. When the preset maximum running time or maximum cumulative running volume is exceeded, the high-pressure constant flow pump will stop running. It can start running normally after a power outage without affecting normal use; however, there will be a running error message. After equipment maintenance, the preset clear command in the control module can be used to clear the records of running time and cumulative running volume stored in the EEPROM IC. This allows the next maintenance cycle to begin, enabling the equipment to restart accumulating running time and volume, ensuring that the high-pressure constant flow pump operates accurately, stably, and reliably.

[0081] The maintenance early warning function reduces the possibility of equipment instability, decreased accuracy, or even shutdown due to wear or failure between material components, thus ensuring precise and stable equipment control.

[0082] As a preferred embodiment, the control module is equipped with a self-resetting fuse, which enables the control module to automatically cut off the power supply when the current exceeds the set value, thus providing overcurrent protection for the control module circuit.

[0083] As a preferred embodiment, the control module is equipped with a Schottky diode to implement reverse connection protection, which prevents end users from accidentally connecting the positive and negative terminals of the power supply during the debugging phase, thus preventing damage to the control module.

[0084] In addition, such as Figure 2 As shown, this embodiment also provides a control method for a high-pressure constant current pump, which specifically includes the following steps:

[0085] S1: Receive control commands and obtain the target flow rate and pressure safety threshold range.

[0086] The control module is powered on and initialized. A preset flow rate command is received from the control module via the communication interface to obtain the target flow rate value Q_target (e.g., 5.0 mL / min).

[0087] At the same time, the system receives preset pressure safety threshold ranges from the control module, such as minimum pressure P_min = 0.5MPa, maximum pressure P_max = 35 MPa, and warning pressure P_alert = 30 MPa.

[0088] The control module can be a host computer, PLC, or microcontroller.

[0089] S2: Based on the target flow rate, calculate the initial theoretical speed of motor 4 and drive motor 4 to run.

[0090] The control module calculates the theoretical initial speed N_theoretical of motor 4 based on the target flow rate Q_target and the known pump displacement V_per_rev (i.e., the volume of liquid discharged by the pump per revolution of motor 4). The calculation formula is: N_theoretical = Q_target / V_per_rev. Subsequently, the control module sends a pulse signal to the stepper motor driver, driving the stepper motor to start running at the speed N_theoretical.

[0091] S3: Obtain the real-time rotational speed of the motor 4 based on the flow detection module, and obtain the real-time output pressure value of the high-pressure constant flow pump based on the pressure detection module.

[0092] During the operation of motor 4, encoder disk 1 rotates synchronously with motor 4. When the light-transmitting hole passes through optocoupler 2, optocoupler 2 generates a pulse signal and sends it to the MCU of the control module. The internal timer of the MCU captures the time interval Δt between the rising edges of two consecutive pulses.

[0093] The MCU calculates the real-time rotational speed of camshaft 3 using the following formula: n_cam = 1 / (m × Δt). Wherein, n_cam is the real-time rotational speed of camshaft 3, and m is the number of pulses generated per revolution of encoder 1. In this embodiment, m = 1.

[0094] Finally, based on the real-time speed of camshaft 3 and the transmission ratio preset by the drive module, the real-time speed n_real of motor 4 is calculated.

[0095] The control module reads the pressure value P_real from the pressure transmitter in real time.

[0096] S4: Determine whether the real-time output pressure value exceeds the pressure safety threshold range.

[0097] If the real-time output pressure value exceeds the pressure safety threshold range, then control motor 4 to perform a safety protection action.

[0098] The MCU determines whether P_real exceeds the preset safety threshold range [P_min, P_max].

[0099] If P_real > P_max or P_real < P_min, the MCU immediately sends an emergency stop command to the stepper motor driver, cutting off the power supply to the motor to stop it from running. At the same time, it illuminates the red LED alarm light and sends an error code to the control module.

[0100] If P_real reaches the warning pressure P_alert but does not exceed P_max, the MCU will light up a yellow LED indicator as a warning, but the pump will continue to run.

[0101] If the real-time output pressure value is within the pressure safety threshold range, then perform the following steps:

[0102] S41: Calculate the actual output flow rate of the high-pressure constant flow pump based on the real-time rotation speed.

[0103] The MCU calculates the actual output flow rate Q_actual of the high-pressure constant flow pump according to the formula Q_actual = n_real * V_per_rev.

[0104] S42: Calculate the ratio of the actual output flow rate to the target flow rate to determine the flow rate ratio coefficient.

[0105] The control module calculates the ratio of the actual output flow rate Q_actual to the target flow rate Q_target.

[0106] Based on this ratio, the traffic proportion coefficient K is determined or updated. In this embodiment, K = (Q_target / Q_actual) * 100%.

[0107] S43: Calculate the target speed of motor 4 based on the target flow rate value and the flow rate ratio coefficient. This involves multiplying the initially calculated theoretical speed N_theoretical by the flow rate ratio coefficient K to obtain the corrected target speed N_corrected.

[0108] S44: Adjust motor 4 to the target speed. That is: N_corrected = N_theoretical * K.

[0109] S5: Closed-loop control and dynamic adjustment

[0110] The control module adjusts the pulse frequency output to the stepper motor driver, so that the motor can be adjusted from the current speed to the new target speed N_corrected.

[0111] After adjustment, the control flow returns to step S3, obtains the latest actual output flow value again, and repeats steps S4 to S5, thereby forming a continuous, adaptive closed-loop control.

[0112] In this closed loop, the MCU can employ a PID control algorithm. It takes the flow deviation (Q_target - Q_actual) as input and dynamically fine-tunes the motor speed through proportional, integral, and derivative operations to achieve rapid response and eliminate steady-state error.

[0113] S6: Maintenance Early Warning (Intelligent Maintenance Process)

[0114] The control module has two accumulators: a running time accumulator and an output flow accumulator.

[0115] Each time the pump starts, the running time accumulator begins to accumulate.

[0116] The output flow accumulator accumulates flow using the real-time integration formula: Total Flow = Q_actual * Sampling Period.

[0117] The MCU compares the accumulated running time with the preset "maximum running time" (e.g., 5000 hours) and the accumulated total output flow with the preset "maximum accumulated flow" (e.g., 2000 liters).

[0118] When any cumulative value exceeds its preset threshold, the MCU will send a maintenance prompt message to the host computer and flash a specific maintenance indicator light on the device panel to remind the user to check or replace vulnerable parts such as pump seals.

[0119] Through the steps of the above embodiments, the present invention achieves high-precision, adaptive, and high-reliability closed-loop control and intelligent management of the flow rate of a high-pressure constant flow pump.

Claims

1. A control method for a high-pressure constant flow pump, characterized in that, The high-pressure constant flow pump includes a motor, a flow detection module, a pressure detection module, and a control module. The control method includes the following steps: Receive control commands and obtain target flow rate and pressure safety threshold range; Based on the target flow rate, the initial theoretical speed of the motor is calculated, and the motor is driven to run. The real-time speed of the motor is obtained based on the flow detection module, and the real-time output pressure value of the high-pressure constant flow pump is obtained based on the pressure detection module. Determine whether the real-time output pressure value exceeds the pressure safety threshold range; If so, then control the motor to perform safety protection actions; If not, proceed with the following steps: The actual output flow rate of the high-pressure constant flow pump is calculated based on the real-time rotation speed. The flow ratio coefficient is determined based on the ratio of the actual output flow value to the target flow value. The target speed of the motor is calculated based on the target flow rate value and the flow rate ratio coefficient. Adjust the motor to the target speed.

2. The control method for the high-pressure constant current pump as described in claim 1, characterized in that, The flow detection module includes an encoder and an optocoupler, and the actual output flow value is indirectly calculated by detecting the rotational speed of the encoder.

3. The control method for the high-pressure constant current pump as described in claim 1, characterized in that, After adjusting the motor speed, the process returns to the step of "obtaining the real-time speed of the motor based on the flow detection module", thus forming a closed-loop control.

4. The control method for the high-pressure constant current pump as described in claim 2, characterized in that, The step of "indirectly calculating the actual output flow rate value by detecting the rotational speed of the encoder" specifically includes: Receives the pulse signal generated by the optocoupler when the code disk rotates; Calculate the time interval between two consecutive pulse signals; Based on the time interval and the physical structure parameters of the encoder, the real-time speed of the motor is calculated. The actual output flow rate is calculated based on the correspondence between the real-time speed of the motor and the pump displacement.

5. The control method for the high-pressure constant current pump as described in claim 1, characterized in that, The step of "calculating the target speed of the motor based on the target flow rate value and the flow rate ratio coefficient" specifically involves multiplying the theoretical speed of the motor calculated based on the target flow rate value by the flow rate ratio coefficient to obtain the corrected target speed.

6. The control method for the high-pressure constant current pump as described in claim 3, characterized in that, In the closed-loop control, the motor speed is dynamically adjusted using a PID control algorithm based on the deviation between the actual output flow rate and the target flow rate.

7. The control method for the high-pressure constant current pump as described in claim 1, characterized in that, The control method also includes a maintenance early warning step: The total operating time or total output flow of the high-pressure constant flow pump is accumulated; the accumulated value is compared with a preset threshold, and a maintenance prompt message is generated when the threshold is exceeded.

8. The control method for the high-pressure constant current pump as described in claim 1, characterized in that, The high-pressure constant flow pump is a dual-plunger pump. The motor drives the dual plungers to move alternately through the camshaft to achieve continuous output and stable pressure in the liquid circuit.

9. The control method for a high-pressure constant current pump as described in claim 2, characterized in that, The high-pressure constant current pump also includes a camshaft, the code disk is fixedly mounted on one end of the camshaft and rotates synchronously with the camshaft, and a light-transmitting hole is provided on its circumference; the optocoupler is fixedly installed, and its transmitting end and receiving end are respectively located on both sides of the code disk and correspond to the position of the light-transmitting hole.

10. A high-pressure constant flow pump, characterized in that, include: Electric motor; The flow detection module is used to detect the output flow of the high-pressure constant flow pump in real time; The pressure detection module is used to detect the pressure of the output fluid circuit in real time. A control module for executing the control method as described in any one of claims 1-9.

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