Intelligent water inlet and outlet flow monitoring system for water pump

Abstract

The application provides a water pump intelligent water inlet and outlet flow monitoring system, which comprises a water inlet detection unit, a water outlet detection unit, a state acquisition unit, a control operation unit, an execution unit and a display communication unit; the water inlet detection unit is arranged on a water inlet pipeline of the water pump and is used for acquiring water inlet flow and water inlet pressure; the water outlet detection unit is arranged on a water outlet pipeline of the water pump and is used for acquiring water outlet flow and water outlet pressure; the state acquisition unit is used for acquiring one or more operating parameters such as liquid level, motor current, motor voltage, motor power, temperature, vibration and valve opening degree; the control operation unit is electrically connected with the water inlet detection unit, the water outlet detection unit, the state acquisition unit, the execution unit and the display communication unit respectively, and the application solves the problems of inaccurate fault identification, high false alarm rate and disconnection between monitoring and control in the prior art.

Description

Technical Field

[0001] This invention relates to the field of water pumps, and more particularly to an intelligent water pump inlet and outlet monitoring system. Background Technology

[0002] Water pumps are widely used in water supply, drainage, mine drainage, agricultural irrigation, and industrial circulating water systems. Their operating status directly affects the safety, stability, and energy consumption of the system. Most existing water pump control systems employ PLCs, frequency converters, and sensors for liquid level, pressure, current, and temperature to achieve pump start-up and shutdown control, operation monitoring, and fault alarms. Some systems also feature remote monitoring and multi-pump linkage capabilities, which can improve the automation level of pumping stations to a certain extent.

[0003] However, existing technologies primarily rely on single parameters such as liquid level, outlet pressure, or motor current for judgment, lacking synchronous monitoring of flow rates on the pump's inlet and outlet sides. This results in only general alarms when conditions such as insufficient suction, outlet blockage, pipeline leakage, pump backflow, dry running, and sensor malfunction occur, making it difficult to accurately identify the fault type. Furthermore, existing systems often employ fixed threshold control, which can easily lead to false alarms, unintended shutdowns, or control lags during pump start-up / shutdown transitions, frequency adjustments, or significant fluctuations in operating conditions. In addition, the existing monitoring system lacks sufficient linkage with the execution control, failing to automatically implement targeted measures such as frequency reduction, valve adjustment, or backup pump switching based on the type of anomaly.

[0004] Therefore, it is necessary to provide a new intelligent water pump inlet and outlet monitoring system to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an intelligent water pump inlet and outlet monitoring system, which solves the problems of inaccurate fault identification, high false alarm rate, and disconnect between monitoring and control in the prior art.

[0006] The intelligent water pump inlet and outlet monitoring system provided by the present invention includes an inlet water detection unit, an outlet water detection unit, a status acquisition unit, a control calculation unit, an execution unit, and a display and communication unit; The water inlet detection unit is installed on the water pump inlet pipe and is used to collect water inlet flow rate and water inlet pressure; The water outlet detection unit is installed on the water pump outlet pipeline to collect water flow rate and water pressure. The status acquisition unit is used to acquire one or more operating parameters among liquid level, motor current, motor voltage, motor power, temperature, vibration, and valve opening. The control and operation unit is electrically connected to the inlet water detection unit, the outlet water detection unit, the status acquisition unit, the execution unit, and the display and communication unit, respectively, and is used to preprocess, calibrate, determine the working condition, and make linkage control decisions on the acquired data. The execution unit is used to perform pump start-up and shutdown, frequency conversion speed regulation, valve control, and standby pump switching; The display and communication unit is used to display real-time operating data, alarm information and historical records, and to send the operating data to the host computer or remote monitoring terminal. The control and calculation unit is used to process the calibrated inlet water flow rate. With water flow rate By comparison, the flow deviation coefficient is obtained.

[0007] Among them, the It is the minimum reference flow constant; The control and calculation unit is also used to calculate the inlet water pressure, outlet water pressure, liquid level, motor current, temperature, and vibration and flow deviation coefficient based on the inlet water pressure, outlet water pressure, liquid level, motor current, temperature, and vibration and flow deviation coefficient. The system uses a combination of factors to identify conditions such as insufficient water absorption, blocked water outlet, pipeline leakage, idling, and sensor malfunction, and outputs corresponding warning, alarm, or shutdown control commands based on the identification results.

[0008] Preferably, the water inlet detection unit includes a first flow meter and a first pressure transmitter. The first flow meter is installed in the main water inlet section at the front end of the water pump inlet, and the first pressure transmitter is installed between the first flow meter and the water pump inlet. The water outlet detection unit includes a second flow meter and a second pressure transmitter. The second flow meter is installed in the main outlet section of the water pump, and the second pressure transmitter is installed between the water pump outlet and the second flow meter. The status acquisition unit includes at least a level sensor installed in a collection well, suction pool, or buffer tank, and a current acquisition module installed in the motor power supply circuit.

[0009] Preferably, the preprocessing of the collected data by the control calculation unit includes: The flow rate, pressure, and current signals are sequentially processed by median filtering and moving average. When the water pump is in the preset delay period after startup, or when the frequency change rate of the inverter output exceeds the set threshold, the control calculation unit will determine the system to be in a transition state. In the transition state, only data will be collected and stored, and no fault judgment will be performed. When any sensor continuously outputs a constant value for more than a set time, or when the rate of change of adjacent sampling points exceeds a preset physical allowable range, the control and calculation unit determines that the corresponding sensor signal is abnormal.

[0010] Preferably, the control calculation unit performs linear calibration on the inlet flow rate and outlet flow rate according to the following formula:

[0011] in, This is the original influent flow rate. The original outflow rate, , For calibration coefficients, , This is the zero-point correction value; And according to

[0012] Calculate the pressure difference between the inlet and outlet, where, For inlet water pressure, This refers to the outlet water pressure.

[0013] Preferably, the control unit determines that the water absorption is insufficient or the water inlet side is short when the following conditions are met simultaneously: The flow deviation coefficient If the water pressure is greater than or equal to the first threshold, the inlet water pressure is lower than the set lower limit, and the liquid level is lower than the set lower limit or the liquid level continues to drop, and the duration of the above state exceeds the first preset time; after determining that the water intake is insufficient or the inlet side is short of water, the control calculation unit outputs a frequency reduction control command to the execution unit, and outputs an alarm command or a stop pump cut-off command if the frequency reduction still does not restore normal operation.

[0014] Preferably, the control unit determines that the outlet pipe is blocked or the outlet valve is malfunctioning when the following conditions are met simultaneously: The water flow rate is lower than the set lower limit, the water pressure is higher than the set upper limit or the inlet and outlet pressure difference is higher than the sum of the reference pressure difference and the first compensation value, the motor current is higher than the sum of the reference current and the second compensation value at the corresponding operating frequency, and the valve opening signal does not change. After determining that the outlet pipe is blocked or the outlet valve is malfunctioning, the control and calculation unit first controls the execution unit to perform a valve reset action. If the valve does not return to normal after the reset, a frequency reduction command or a shutdown protection command is output.

[0015] Preferably, the control calculation unit simultaneously satisfies the flow deviation coefficient. If the water pressure is greater than or equal to the second threshold, the water pressure is lower than the reference water pressure at the corresponding operating frequency minus the third compensation value, and the inlet flow rate is greater than the outlet flow rate and continues to exceed the second preset time, it is determined to be a pipeline leak or pump backflow abnormal condition. The control and processing unit determines a sensor malfunction condition when any of the following situations occur: The sensor output remains continuously and unchanged for more than the set duration; The sensor's adjacent sampled values ​​abruptly change beyond the reasonable range. The sensor output exceeds the upper or lower limit of its measurement range; The correspondence between flow rate, pressure, and current does not conform to the preset water pump operating reference table.

[0016] Preferably, the control and operation unit adopts a three-level linkage control method, including early warning control, alarm control and shutdown protection control; The early warning control is used to control the display communication unit to output early warning information and control the frequency converter to reduce the operating frequency of the water pump or control the valve to perform a reset action when the fault judgment condition is met for the first time and the duration is short. The alarm control is used to control the display communication unit to output alarm information and control the execution unit to reduce the faulty pump to a safe frequency when the fault state persists after the warning, and at the same time start the backup pump preparation logic. The shutdown protection control is used to disconnect the operating circuit of the faulty pump, close the outlet valve of the faulty pump, and start the standby pump when the fault continues to reach the shutdown condition, or when any one of the following is accompanied by excessive temperature, excessive vibration, or severe overcurrent.

[0017] The beneficial effects of this invention are: 1. This invention achieves synchronous acquisition of inflow and outflow by setting flow detection units on the inlet and outlet sides of the water pump, and combines inlet and outlet pressure, liquid level and motor operating parameters for comprehensive analysis, which can more accurately reflect the actual operating status of the water pump.

[0018] 2. This invention uses the deviation between inlet and outlet water volume as the core criterion for judgment, and can classify and identify working conditions such as insufficient water intake, water blockage, pipeline leakage, pump backflow, dry running, and sensor malfunction. It solves the problem of relying on a single parameter for judgment and inaccurate fault type identification in the prior art.

[0019] 3. This invention incorporates data filtering, calibration, and transition state shielding mechanisms, which can reduce the impact of pump start-up and shutdown, frequency conversion speed regulation, and operating condition fluctuations on the detection results, thereby effectively reducing false alarms and false shutdowns and improving the reliability of monitoring results.

[0020] 4. This invention directly links the fault diagnosis results with the frequency converter speed regulation, valve control and standby pump switching, and can automatically perform frequency reduction, alarm, pump cut-off or shutdown protection according to different abnormality types, thus solving the problem of monitoring and control being disconnected in the prior art.

[0021] 5. This invention is applicable to both single water pumps and control scenarios involving multiple pump sets in parallel, exhibiting strong engineering adaptability and facilitating its widespread application in water supply, drainage, mining, agricultural irrigation, and industrial circulating water systems. Attached Figure Description

[0022] Figure 1 A schematic diagram of the overall structure of the intelligent water pump inlet and outlet monitoring system provided by the present invention; Figure 2 This is a connection diagram of the detection unit and control unit provided by the present invention; Figure 3 The fault classification and discrimination flowchart provided by the present invention; Figure 4 The diagram shows the structure of the water pump body provided by this invention.

[0023] The following are the labels in the diagram: 1. Pump body; 2. Inlet pipe; 3. Outlet pipe; 4. First flow meter; 5. First pressure transmitter; 6. Second flow meter; 7. Second pressure transmitter. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Please refer to the following: Figure 1 , Figure 2 , Figure 3 as well as Figure 4 ,in Figure 1 A schematic diagram of the overall structure of the intelligent water pump inlet and outlet monitoring system provided by the present invention; Figure 2 This is a connection diagram of the detection unit and control unit provided by the present invention; Figure 3 The fault classification and discrimination flowchart provided by the present invention; Figure 4 The diagram shows the structure of the water pump body provided by this invention.

[0026] Example 1 This embodiment is applicable to the operation monitoring scenarios of a single centrifugal pump, a single submersible pump, or a single industrial water pump.

[0027] like Figure 1-4 As shown, an intelligent water pump inlet and outlet monitoring system includes a water pump body 1, an inlet pipe 2, an outlet pipe 3, a first flow meter 4, a first pressure transmitter 5, a second flow meter 6, a second pressure transmitter 7, a liquid level sensor, a current acquisition module, a temperature sensor, a vibration sensor, a PLC controller, a frequency converter, a contactor, an audible and visual alarm, a touch screen, and a remote communication module.

[0028] The first flow meter 4 is installed on the inlet pipe 2 to collect the inlet water flow. The first pressure transmitter 5 is installed at the front end of the water pump inlet to collect the inlet water pressure. The second flow meter 6 is installed on the outlet pipe 3 to collect the outlet flow rate. The second pressure transmitter 7 is installed at the rear end of the water pump outlet to collect the outlet water pressure. The liquid level sensor is installed in the suction tank, collection well, or buffer tank to collect liquid level data. The current acquisition module is used to collect the motor's operating current. Temperature sensors are installed on the motor windings or bearings to collect temperature data. Vibration sensors are installed on the pump housing or bearing housing to collect vibration values. .

[0029] The PLC controller is electrically connected to the first flow meter, the first pressure transmitter, the second flow meter, the second pressure transmitter, the level sensor, the current acquisition module, the temperature sensor, the vibration sensor, the frequency converter, the contactor, the audible and visual alarm, the touch screen, and the remote communication module. The PLC can adopt a modular structure commonly used in industrial settings, and achieve parameter acquisition and control linkage through analog input, digital input and output, and communication modules. This type of PLC architecture and its data interaction method with the host computer or remote terminal already have a mature engineering foundation in existing pump station automation systems.

[0030] In this embodiment, the PLC controller reads data from each sensor with a sampling period of 100ms and generates a diagnostic data packet every 1 second. To avoid misjudgments caused by start-up / shutdown or electromagnetic interference, the PLC controller first performs three-point median filtering on the flow, pressure, and current signals, and then performs five-point moving average processing. If the water pump starts within 30 seconds, or the frequency change rate of the inverter output exceeds 1Hz or s, the system only saves the data and does not perform fault classification judgment.

[0031] The PLC controller calibrates the original inlet flow rate and the original outlet flow rate separately:

[0032] in, , For calibration coefficients, , This is the zero-point correction value.

[0033] Subsequently, the PLC controller calculates the flow deviation coefficient:

[0034] in, The minimum reference flow constant is preferably 8% of the rated flow rate.

[0035] Simultaneously calculate the inlet and outlet pressure difference:

[0036] PLC controller according to , , , , , and The combination relationship is used to determine the working condition: when , The liquid level is below the set lower limit and the liquid level When the water level continues to drop, it is determined to be an insufficient water absorption condition; when Below the lower limit of water discharge Exceeding the upper limit of water output and current When the value is higher than the reference value, it is determined to be a blockage in the outlet pipe or an abnormal condition of the outlet valve; when , ,and When the pressure is lower than the reference pressure at the corresponding frequency, it is determined to be a pipeline leak or an abnormal backflow condition in the pump; when and When all flow rates are below the set minimum and the motor is still running, it is determined to be an idling condition; when a certain sensor remains unchanged for 60 seconds, or the rate of change of its adjacent sampling points exceeds the physical allowable range, it is determined to be a fault of the corresponding sensor.

[0037] In this embodiment, the system adopts a three-level linkage control.

[0038] Early warning level: The touchscreen displays the fault type, the audible and visual alarm emits intermittent alarms, and the PLC controls... Reduce the frequency of the inverter by 2-3 Hz; Alarm level: After 10 seconds of continuous abnormality, the PLC controller will reduce the operating frequency to a safe frequency and send an alarm data packet to the remote communication module; Shutdown level: When the abnormality lasts for more than 30 seconds, or is accompanied by any of the following: temperature exceeding the limit, vibration exceeding the limit, or current exceeding the limit, the PLC control contactor cuts off the faulty pump circuit and shuts down for protection.

[0039] This embodiment employs flow and pressure detection elements simultaneously on both the inlet and outlet sides, combining liquid level and electrical parameters to achieve correlation discrimination, unlike traditional pump control methods that rely solely on single-sided pressure or liquid level for start / stop. In existing pump station projects, multi-parameter monitoring of liquid level, water pressure, current, temperature, and flow, as well as fault protection and backup circuit switching, have mature application foundations. This embodiment further integrates "inlet / outlet flow deviation" as the core discrimination parameter.

[0040] Example 2 This embodiment is applicable to scenarios where multiple pumps operate in parallel, such as drainage stations in water collection wells, central pump rooms in mines, and industrial circulating water drainage rooms. In existing projects, multi-pump systems often use PLCs to receive parameters such as liquid level, pressure, flow rate, and current, and support local control, centralized control, remote control, and automatic switching of standby pumps.

[0041] This embodiment includes three working pumps A, B, and C, and one standby pump D. Each pump is equipped with an independent inlet flow meter, inlet pressure transmitter, outlet flow meter, outlet pressure transmitter, current acquisition module, and temperature sensor. Analog level sensors and digital high / low level switches are installed in the common suction tank of each pump to simultaneously achieve continuous level monitoring and limit level protection. This combination of analog and digital level sensors improves monitoring reliability.

[0042] The PLC controller divides the water level in the suction tank into four control threshold levels: lower limit level L2, lower limit level L1, upper limit level H1, and upper limit level H2.

[0043] When the liquid level is below L2, the PLC disables all water pumps from starting. When the liquid level is between L1 and H1, only one priority pump is allowed to operate; When the liquid level is higher than H1, the PLC activates the second water pump based on the flow gap and the rate of liquid level rise. When the liquid level is higher than H2, the PLC simultaneously starts the third water pump and sends a high liquid level alarm to the monitoring terminal.

[0044] This type of level linkage control based on H2, H1, L1, and L2 levels already has mature engineering solutions in the scenario of central pump room in mines, so we will not go into too much detail here.

[0045] In this embodiment, the PLC controller not only starts and stops the pump based on the liquid level, but also calculates the flow deviation coefficient for each pump separately. , , , When a certain operating pump If the value remains above 0.10 and the outlet water pressure deviates from the reference value by more than 10%, the PLC will mark it as an abnormal pump. Here, pressure deviation from the set value by ±10%, temperature exceeding 75℃, and vibration amplitude exceeding 0.15mm can be used as one of the preferred protection threshold settings to facilitate the formation of protection parameters that can be implemented in engineering.

[0046] If pump A is marked as an abnormal pump, perform the following steps: S21: The PLC first reduces the frequency of pump A to 85% of its original operating frequency; S22: If after 5 seconds If it is still greater than 0.10, start the standby pump D and put it into operation at 80% of its rated frequency; S23: After pump D has been running stably for 10 seconds, disconnect pump A; S24: Upload the fault code of pump A, switching time, and flow and pressure data before and after switching to the host computer; S25: If the standby pump D fails to start, the remaining operating pumps will continue to work, and a level 2 alarm will be issued.

[0047] In addition, this embodiment includes pump group rotation control. The PLC records the cumulative running time of each pump and reorders the priorities every 24 hours; the pump with the longest running time is deactivated when the switching conditions are met, and the pump with the shortest running time is activated first. To prevent a sudden drop in total water output during rotation, the PLC first starts the pump to be activated, and then disconnects the original main pump after it has been running stably for 30 seconds. This embodiment also includes pre-start pressure confirmation logic: when the pressure of the public drainage main pipe does not reach the pre-filling water setting value, the PLC prohibits the high-pressure pump from starting; if an abnormal pressure is detected during operation, the corresponding pump is shut down and the standby pump is started simultaneously.

[0048] Example 3 This embodiment is applicable to large-scale water intake pumping stations, urban water supply pumping stations, or industrial circulating water supply systems, and focuses on demonstrating the application of this invention in monitoring, speed regulation, and remote operation and maintenance.

[0049] This embodiment includes two main pumps and one standby pump. Each main pump is equipped with a frequency converter, inlet flow meter, outlet flow meter, inlet and outlet pressure transmitters, motor current sensor, bearing temperature sensor, and vibration sensor. A PLC serves as the control core, communicating with a touchscreen, industrial Ethernet switch, host computer, and remote monitoring platform. In existing large-scale water intake pumping station energy-saving renovations, PLCs, combined with flow and pressure sensors, variable frequency speed control, and remote monitoring, have formed a mature system foundation.

[0050] In this embodiment, in addition to performing the aforementioned flow deviation judgment, the PLC also performs closed-loop pressure speed regulation. The target outlet water pressure is set as... The water pressure can be measured in real time. The pressure deviation is:

[0051] The PLC outputs the frequency correction amount based on the proportional-integral-derivative algorithm:

[0052] And set the inverter's output frequency to:

[0053] in, This is the reference frequency.

[0054] When the outlet water pressure is lower than the target value, the PLC increases the frequency; when the outlet water pressure is higher than the target value, the PLC decreases the frequency. This type of PLC-based real-time pressure or flow feedback speed regulation and PID closed-loop control is a mature engineering approach for energy-saving retrofitting of large-scale water intake pumping stations.

[0055] To avoid ignoring pump malfunctions by relying solely on pressure-based speed regulation, this embodiment introduces dual-constraint speed regulation logic: when And flow deviation coefficient Normal frequency increase is allowed at this time; when but At this time, the PLC does not directly increase the frequency, but first determines whether there is insufficient water absorption or leakage abnormality; when Furthermore, when the inlet water pressure continues to drop, the PLC enters the protection speed regulation mode, which only allows frequency reduction and does not allow frequency increase; when Furthermore, when the temperature or vibration exceeds the limit, the PLC directly exits the PID speed regulation and executes a shutdown to cut off the pump.

[0056] In this embodiment, the remote monitoring platform stores the following data: average influent flow rate per minute, average effluent flow rate per minute, flow deviation coefficient curve, inlet and outlet pressure curves, motor current curve, start / stop logs, alarm logs, and pump unit switching logs. Management personnel can view the real-time operating status via a touchscreen, local host computer, or remote terminal, and can select manual, automatic, or remote modes. In existing pump station systems, the local, centralized, and remote control modes, as well as the remote terminal monitoring of pump station equipment status, already have a solid engineering foundation.

[0057] In this embodiment, the following protection threshold is preferably set: The bearing temperature warning threshold is 75℃; The vibration warning threshold is 0.15 mm; The allowable deviation of the water supply pressure is ±10% of the set value; The flow rate threshold for detecting valve seal leakage is 5L or min.

[0058] These thresholds can be used as preferred engineering parameters for the deployment of the system of the present invention in high-flow pumping station scenarios.

[0059] When this embodiment is running, if it is detected that a main pump is in an inefficient zone for a long time during the off-peak water supply period, the PLC will automatically reduce the number of running pumps according to the real-time water supply changes and implement frequency conversion regulation on the main pumps that are kept running; if the water supply demand increases, a second main pump will be put back into operation.

[0060] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A smart water pump inlet and outlet water volume monitoring system, characterized in that, It includes an inlet water detection unit, an outlet water detection unit, a status acquisition unit, a control and calculation unit, an execution unit, and a display and communication unit; The water inlet detection unit is installed on the water pump inlet pipe and is used to collect water inlet flow rate and water inlet pressure; The water outlet detection unit is installed on the water pump outlet pipeline to collect water flow rate and water pressure. The status acquisition unit is used to acquire one or more operating parameters among liquid level, motor current, motor voltage, motor power, temperature, vibration, and valve opening. The control and operation unit is electrically connected to the inlet water detection unit, the outlet water detection unit, the status acquisition unit, the execution unit, and the display and communication unit, respectively, and is used to preprocess, calibrate, determine the working condition, and make linkage control decisions on the acquired data. The execution unit is used to perform pump start-up and shutdown, frequency conversion speed regulation, valve control, and standby pump switching; The display and communication unit is used to display real-time operating data, alarm information and historical records, and to send the operating data to the host computer or remote monitoring terminal. The control and calculation unit is used to process the calibrated inlet water flow rate. With water flow rate By comparison, the flow deviation coefficient is obtained.

2. Wherein, the It is the minimum reference flow constant; The control and calculation unit is also used to calculate the inlet water pressure, outlet water pressure, liquid level, motor current, temperature, and vibration and flow deviation coefficient based on the inlet water pressure, outlet water pressure, liquid level, motor current, temperature, and vibration and flow deviation coefficient. The system uses a combination of factors to identify conditions such as insufficient water absorption, blocked water outlet, pipeline leakage, idling, and sensor malfunction, and outputs corresponding warning, alarm, or shutdown control commands based on the identification results.

3. The intelligent water pump inlet and outlet monitoring system according to claim 1, characterized in that, The water inlet detection unit includes a first flow meter and a first pressure transmitter. The first flow meter is installed in the main water inlet section at the front end of the water pump inlet, and the first pressure transmitter is installed between the first flow meter and the water pump inlet. The water outlet detection unit includes a second flow meter and a second pressure transmitter. The second flow meter is installed in the main outlet section of the water pump, and the second pressure transmitter is installed between the water pump outlet and the second flow meter. The status acquisition unit includes at least a level sensor installed in a collection well, suction pool, or buffer tank, and a current acquisition module installed in the motor power supply circuit.

4. The intelligent water pump inlet and outlet monitoring system according to claim 1, characterized in that, The preprocessing of the collected data by the control and processing unit includes: The flow rate, pressure, and current signals are sequentially processed by median filtering and moving average. When the water pump is in the preset delay period after startup, or when the frequency change rate of the inverter output exceeds the set threshold, the control calculation unit will determine the system to be in a transition state. In the transition state, only data will be collected and stored, and no fault judgment will be performed. When any sensor continuously outputs a constant value for more than a set time, or when the rate of change of adjacent sampling points exceeds a preset physical allowable range, the control and calculation unit determines that the corresponding sensor signal is abnormal.

5. The intelligent water pump inlet and outlet monitoring system according to claim 1, characterized in that, The control calculation unit performs linear calibration on the inlet and outlet flow rates according to the following formula:

6. Among them, This is the original influent flow rate. The original outflow rate, , For calibration coefficients, , This is the zero-point correction value; And according to 7. Calculate the pressure difference between the inlet and outlet, where, For inlet water pressure, This refers to the outlet water pressure.

8. The intelligent water pump inlet and outlet monitoring system according to claim 1, characterized in that, The control unit determines that the operation is in a state of insufficient water absorption or water shortage on the inlet side when the following conditions are met simultaneously: The flow deviation coefficient If the water pressure is greater than or equal to the first threshold, the inlet water pressure is lower than the set lower limit, and the liquid level is lower than the set lower limit or the liquid level continues to drop, and the duration of the above state exceeds the first preset time; after determining that the water intake is insufficient or the inlet side is short of water, the control calculation unit outputs a frequency reduction control command to the execution unit, and outputs an alarm command or a stop pump cut-off command if the frequency reduction still does not restore normal operation.

9. The intelligent water pump inlet and outlet monitoring system according to claim 1, characterized in that, The control unit determines that the outlet pipe is blocked or the outlet valve is malfunctioning when the following conditions are met simultaneously: The water flow rate is lower than the set lower limit, the water pressure is higher than the set upper limit or the inlet and outlet pressure difference is higher than the sum of the reference pressure difference and the first compensation value, the motor current is higher than the sum of the reference current and the second compensation value at the corresponding operating frequency, and the valve opening signal does not change. After determining that the outlet pipe is blocked or the outlet valve is malfunctioning, the control and calculation unit first controls the execution unit to perform a valve reset action. If the valve does not return to normal after the reset, a frequency reduction command or a shutdown protection command is output.

10. The intelligent water pump inlet and outlet monitoring system according to claim 1, characterized in that, The control calculation unit simultaneously satisfies the flow deviation coefficient If the water pressure is greater than or equal to the second threshold, the water pressure is lower than the reference water pressure at the corresponding operating frequency minus the third compensation value, and the inlet flow rate is greater than the outlet flow rate and continues to exceed the second preset time, it is determined to be a pipeline leak or pump backflow abnormal condition. The control and processing unit determines a sensor malfunction condition when any of the following situations occur: The sensor output remains continuously and unchanged for more than the set duration; The sensor's adjacent sampled values ​​abruptly change beyond the reasonable range. The sensor output exceeds the upper or lower limit of its measurement range; The correspondence between flow rate, pressure, and current does not conform to the preset water pump operating reference table.

11. The intelligent water pump inlet and outlet monitoring system according to claim 1, characterized in that, The control and operation unit adopts a three-level linkage control method, including early warning control, alarm control and shutdown protection control; The early warning control is used to control the display communication unit to output early warning information and control the frequency converter to reduce the operating frequency of the water pump or control the valve to perform a reset action when the fault judgment condition is met for the first time and the duration is short. The alarm control is used to control the display communication unit to output alarm information and control the execution unit to reduce the faulty pump to a safe frequency when the fault state persists after the warning, and at the same time start the backup pump preparation logic. The shutdown protection control is used to disconnect the operating circuit of the faulty pump, close the outlet valve of the faulty pump, and start the standby pump when the fault continues to reach the shutdown condition, or when any one of the following is accompanied by excessive temperature, excessive vibration, or severe overcurrent.

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