Liquid ammonia pump filtering and differential pressure monitoring protection method and device with blockage early warning

Abstract

The application discloses a liquid ammonia pump filtering and differential pressure monitoring and protection method and device with blockage early warning. The method is related to the filtering differential pressure signal, the liquid ammonia mass flow, the pump inlet temperature and the preset clean filter reference differential pressure, and is used for obtaining a filter blockage characteristic value, and determining a filter blockage early warning grade in combination with the pump pressure rise check amount, the supercooling degree margin or the available cavitation margin, and then outputting an early warning signal and executing corresponding protection actions. The technical scheme of the application can accurately identify the filter blockage degree by correlatively checking the filtering differential pressure, the liquid ammonia mass flow, the pump inlet temperature, the pump pressure rise check amount and the available cavitation margin, reduces the false alarm and missed alarm risks, timely executes the flow limiting, speed limiting or pump stopping protection, and improves the liquid ammonia pump operation safety and test data reliability.

Description

Technical Field

[0001] This invention relates to the technical field of liquid ammonia pump monitoring, and in particular to a method and device for filtering and differential pressure monitoring and protection of liquid ammonia pumps with blockage early warning. Background Technology

[0002] Liquid ammonia pumps play a crucial role in applications such as space thermal control, cryogenic medium circulation, special fluid transportation, and pump performance testing. Due to the characteristics of liquid ammonia, including its easy vaporization, significant pressure variations with temperature, and high safety risks, liquid ammonia pumps typically require maintaining the inlet medium as a single-phase subcooled liquid during operation. Parameters such as inlet pressure, inlet temperature, pressure difference across the pump, flow rate, and rotational speed are continuously monitored. To prevent particulate impurities from entering precision components such as the pump body, flow meter, regulating valve, and heat exchanger, filters are generally installed in the liquid ammonia circulation loop. These filters primarily protect the pump's internal flow channels, impeller, bearings, and sealing structures.

[0003] In existing liquid ammonia pump testing or operation schemes, filters are mostly used as ordinary mechanical filtration components. The condition of the filter element is typically judged by periodic disassembly and inspection, manual maintenance, or a single differential pressure threshold. This makes it difficult to promptly identify differences between gradual clogging, sudden clogging, or normal increases in differential pressure due to flow rate changes. When the filter is clogged, the pump inlet resistance increases, potentially leading to a decrease in inlet absolute pressure, reduced subcooling margin, or insufficient available NPSH, thereby inducing cavitation, flow fluctuations, and increased pump performance testing errors. Existing schemes also lack an online early warning mechanism that correlates and verifies filter differential pressure, pump pressure rise, mass flow rate, inlet temperature, and liquid ammonia properties, making them prone to false alarms, missed alarms, or delayed protection actions. How to properly solve these problems has become a pressing issue for the industry. Summary of the Invention

[0004] This invention provides a method and device for filtering and monitoring differential pressure of a liquid ammonia pump with blockage warning, which can identify filter blockage online and issue graded warnings to reduce false judgments, protect the liquid ammonia pump in a timely manner, and improve operational safety and data reliability.

[0005] According to a first aspect of the present invention, a method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning is provided. This method is executed by a measurement and control unit and applied to a closed-loop circulation circuit of a liquid ammonia pump. The closed-loop circulation circuit includes a reservoir, a filter, a pump under test, a mass flow meter, a flow regulating valve, and a heat exchanger along the liquid ammonia flow direction. A first differential pressure sensor is connected across both ends of the filter, and a second differential pressure sensor is connected across both ends of the pump under test. The method is characterized by comprising: During the operation of the pump under test, signals from the first differential pressure sensor, the second differential pressure sensor, the absolute pressure at the pump inlet, the pump inlet temperature, the pump outlet pressure, the mass flow rate of liquid ammonia, the pump speed, and the opening of the flow regulating valve are collected simultaneously to obtain a set of operating data at the same sampling time. The first differential pressure sensor signal in the operating data set is correlated with the liquid ammonia mass flow rate, pump inlet temperature and preset clean filter element reference differential pressure to obtain the filter element blockage characterization value, and the second differential pressure sensor signal in the operating data set is used as the pump pressure rise verification quantity. The filter element clogging characterization value is compared with the corresponding clogging warning threshold, clogging protection threshold and clogging change rate threshold. The comparison result is then checked for operating conditions using the pump pressure rise verification value. Finally, the subcooling margin or available cavitation margin obtained from the pump inlet absolute pressure and pump inlet temperature is combined to determine the filter element clogging warning level. Based on the filter element clogging warning level, an early warning signal is output, and when the filter element clogging warning level reaches the protection condition, at least one of the following protective actions is executed: reducing the target flow rate, limiting the pump speed, stopping the pump, and prompting to replace the filter element. At the same time, the operating data set before and after the trigger, the filter element clogging characterization value, and the filter element clogging warning level are stored.

[0006] In one embodiment, synchronously acquiring signals and obtaining a set of running data includes: The first differential pressure sensor, the second differential pressure sensor, the pressure sensor, the temperature sensor, the mass flow meter, the speed sensor, and the valve position feedback module are triggered to sample using the same clock pulse, and a timestamp is written for each sampled value. Align the sampled values ​​whose timestamps fall within the same sampling period, and add an anomaly flag to sampled values ​​that are missing, out of range, have zero drift exceeding the set value, or have failed communication verification. When the fluctuations in pump speed, liquid ammonia mass flow rate, and flow control valve opening are all below the corresponding stable threshold, a steady-state window is established, and the sampled values ​​without anomaly markers within the steady-state window are filtered and averaged. The filtered and averaged sampled values ​​are combined with the anomaly markers to form the running data group.

[0007] In one embodiment, obtaining the filter element clogging characterization value includes: After installing the clean filter element, the filtration pressure difference was collected under multiple combinations of liquid ammonia mass flow rate, pump inlet temperature and pump speed to establish a clean reference pressure difference function. The current operating conditions are determined based on the liquid ammonia mass flow rate, pump inlet temperature, and pump speed in the operating data set, and the current reference pressure difference is obtained by compensating the clean reference pressure difference function with the liquid ammonia density and liquid ammonia viscosity. The deviation of the measured differential pressure from the first differential pressure sensor from the current reference differential pressure is used to generate a filter element clogging characterization value; If no warning is triggered and the steady-state window continues to meet the set time, the clean reference pressure difference function is updated based on the measured pressure difference without anomaly markers within the steady-state window, according to an update weight less than the set learning coefficient.

[0008] In one embodiment, determining the filter clogging warning level includes: Calculate the sliding average value and the rate of change per unit time for the filter element clogging characterization values; When the moving average reaches the first warning threshold and N consecutive steady-state windows are met, or when the rate of change per unit time reaches the sudden increase threshold, it is determined to be a level one warning, where N is an integer not less than 2; When the sliding average reaches the second warning threshold, or when the duration of the first-level warning exceeds the set time, it is determined to be a second-level warning; When the sliding average value reaches the clogging protection threshold, or the filter element clogging characterization value reaches the second warning threshold and the subcooling margin or available NPSH margin is lower than the protection margin, it is determined to be a level three protection.

[0009] In one embodiment, before determining the filter clogging warning level, the following is included: The trend of the measured differential pressure of the first differential pressure sensor changing with the square of the liquid ammonia mass flow rate is compared with the current reference differential pressure. If both increase proportionally and the filter element blockage characterization value does not reach the first warning threshold, the current filter element blockage warning level is maintained. The pump pressure rise calibration value of the second differential pressure sensor is compared with the difference between the pump outlet pressure and the pump inlet absolute pressure. If the deviation exceeds the calibration threshold, the differential pressure sensor or pressure sensor is marked as abnormal, and the filter clogging warning level upgrade triggered based on the pump pressure rise calibration value is suspended. When the absolute pressure at the pump inlet is lower than the lower limit of the inlet pressure, the abnormality will be classified as an inlet liquid supply risk, and the filter element blockage warning level will be raised by at least one level. The lower limit of the inlet pressure is the sum of the saturation pressure corresponding to the pump inlet temperature and the safety pressure margin.

[0010] In one embodiment, protective actions are performed based on the filter clogging warning level, including: When the filter element clogging warning level is Level 1, a filter element maintenance prompt is output to maintain the operation of the tested pump, and the remaining operating time to reach Level 2 or Level 3 protection is predicted based on the changing trend of the filter element clogging characterization value. When the filter element clogging warning level is Level 2, increase the sampling frequency, limit the target speed of the tested pump or the target flow rate of liquid ammonia, and output a filter element replacement prompt. When the filter element clogging warning level is level three protection, a pump stop command is sent to the pump under test, the operating data set within the preset time period before the pump stop is recorded, and a maintenance prompt prohibiting restart is output. After the filter element is replaced, the filtration differential pressure is re-acquired under low-speed operation. If the filter element blockage indicator value is lower than the reset threshold, the maintenance prompt prohibiting restart is lifted, and the data of the replaced clean filter element is used to update the clean reference differential pressure function.

[0011] According to a second aspect of the present invention, a liquid ammonia pump filtration and differential pressure monitoring protection device with blockage warning is provided, applied to a closed-loop circulation circuit of a liquid ammonia pump. The closed-loop circulation circuit includes a reservoir, a filter, a pump under test, a mass flow meter, a flow regulating valve, and a heat exchanger along the liquid ammonia flow direction. A first differential pressure sensor is connected across both ends of the filter, and a second differential pressure sensor is connected across both ends of the pump under test. The device is characterized by comprising: The acquisition module is used to simultaneously acquire signals from the first differential pressure sensor, the second differential pressure sensor, the absolute pressure at the pump inlet, the pump inlet temperature, the pump outlet pressure, the mass flow rate of liquid ammonia, the pump speed, and the opening of the flow regulating valve during the operation of the pump under test, so as to obtain a set of operating data at the same sampling time. The calculation module is used to correlate the first differential pressure sensor signal in the operating data group with the liquid ammonia mass flow rate, pump inlet temperature and preset clean filter element reference differential pressure to obtain the filter element blockage characterization value, and use the second differential pressure sensor signal in the operating data group as the pump pressure rise verification quantity; The determination module is used to compare the filter element clogging characterization value with the corresponding clogging warning threshold, clogging protection threshold and clogging change rate threshold, and to use the pump pressure rise verification amount to perform working condition verification on the comparison result. Then, combined with the subcooling margin or available cavitation margin obtained from the pump inlet absolute pressure and pump inlet temperature, the filter element clogging warning level is determined. The execution module is used to output a warning signal based on the filter element clogging warning level, and when the filter element clogging warning level reaches the protection condition, execute at least one of the following protective actions: reducing the target flow rate, limiting the pump speed, stopping the pump, and prompting to replace the filter element. At the same time, it stores the operating data set before and after the trigger, the filter element clogging characterization value, and the filter element clogging warning level.

[0012] According to a third aspect of the present invention, an electronic device is provided, comprising: a communication interface, a processor, and a memory; The memory is used to store program instructions, which, when executed by the processor that is connected to the memory via the communication interface, implement any of the above-described methods for filtering and differential pressure monitoring of liquid ammonia pumps with blockage warning.

[0013] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, on which computer program instructions are stored, which, when executed by a computer (e.g., a processor in a computer), implement any of the above-described methods for filtering and differential pressure monitoring of a liquid ammonia pump with blockage warning.

[0014] In summary, this invention provides a method and device for filtration and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning. The method includes: applying the method to a closed-loop circulation circuit of the liquid ammonia pump; a monitoring and control unit simultaneously collecting filter differential pressure, pump differential pressure, pump inlet absolute pressure, pump inlet temperature, pump outlet pressure, liquid ammonia mass flow rate, pump speed, and flow control valve opening during the operation of the pump under test, forming a set of operating data at the same sampling time; correlating the filter differential pressure signal with the liquid ammonia mass flow rate, pump inlet temperature, and a preset clean filter element reference differential pressure to calculate a filter element blockage characterization value; and combining this with the pump pressure rise check, subcooling margin, or available NPSH to determine the filter element blockage early warning level, thereby outputting an early warning signal and executing corresponding protective actions. The technical solution of this invention, by correlating and verifying the filter differential pressure with the liquid ammonia mass flow rate, pump inlet temperature, pump pressure rise check, and available NPSH, can accurately identify the degree of filter element blockage, reduce the risk of false alarms and missed alarms, and promptly execute flow limiting, speed limiting, or pump shutdown protection, thereby improving the operational safety of the liquid ammonia pump and the reliability of test data.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and drawings.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a liquid ammonia pump filtration and differential pressure monitoring protection method with blockage early warning, provided as an embodiment of the present invention; Figure 2 A flowchart of another liquid ammonia pump filtration and differential pressure monitoring protection method with blockage early warning provided for an embodiment of the present invention; Figure 3A flowchart illustrating another method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning, provided as an embodiment of the present invention; Figure 4 A flowchart illustrating another method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning, provided as an embodiment of the present invention; Figure 5 A flowchart illustrating another method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning, provided as an embodiment of the present invention; Figure 6 A flowchart illustrating another method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning, provided as an embodiment of the present invention; Figure 7 A structural diagram of a liquid ammonia pump filtration and differential pressure monitoring and protection device with blockage early warning provided for an embodiment of the present invention; Figure 8 A structural diagram of an electronic device provided as an embodiment of the present invention; Figure 9 A physical diagram of a differential pressure sensor provided for an embodiment of the present invention. Detailed Implementation

[0019] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present invention and not to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the invention.

[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0021] like Figure 1As shown, this invention provides a method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning. Executed by a measurement and control unit, it is applied to a closed-loop circulation circuit of a liquid ammonia pump. The closed-loop circuit includes a reservoir, a filter, a pump under test, a mass flow meter, a flow regulating valve, and a heat exchanger along the liquid ammonia flow direction. A first differential pressure sensor is connected across the two ends of the filter, and a second differential pressure sensor is connected across the two ends of the pump under test. The method is characterized by including: In step S11, during the operation of the pump under test, the signals of the first differential pressure sensor, the second differential pressure sensor, the absolute pressure at the pump inlet, the pump inlet temperature, the pump outlet pressure, the mass flow rate of liquid ammonia, the pump speed, and the opening of the flow regulating valve are collected simultaneously to obtain a set of operating data at the same sampling time. In step S12, the first differential pressure sensor signal in the operating data set is correlated with the liquid ammonia mass flow rate, pump inlet temperature and preset clean filter element reference differential pressure to obtain the filter element blockage characterization value, and the second differential pressure sensor signal in the operating data set is used as the pump pressure rise verification quantity. In step S13, the filter element clogging characterization value is compared with the corresponding clogging warning threshold, clogging protection threshold and clogging change rate threshold, and the comparison result is checked using the pump pressure rise verification amount. Then, combined with the subcooling margin or available cavitation margin obtained from the pump inlet absolute pressure and pump inlet temperature, the filter element clogging warning level is determined. In step S14, a warning signal is output according to the filter element clogging warning level, and when the filter element clogging warning level reaches the protection condition, at least one of the following protection actions is executed: reducing the target flow rate, limiting the pump speed, stopping the pump, and prompting to replace the filter element. At the same time, the operating data set before and after the trigger, the filter element clogging characterization value, and the filter element clogging warning level are stored.

[0022] This embodiment provides a method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning. This method is executed by a measurement and control unit and applied to a closed-loop circulation system of the liquid ammonia pump. The closed-loop circulation system of the liquid ammonia pump includes a reservoir, a filter, a pump under test, a mass flow meter, a flow regulating valve, and a heat exchanger arranged along the liquid ammonia flow direction. A first differential pressure sensor is connected across both ends of the filter, and a second differential pressure sensor is connected across both ends of the pump under test. An absolute pressure sensor and a temperature sensor are installed at the pump inlet, and a pressure sensor is installed at the pump outlet. The mass flow meter is located before the flow regulating valve. This arrangement allows for the acquisition of filter differential pressure, pump pressure rise, pump inlet phase parameters, and liquid ammonia mass flow rate, making it suitable for online judgment of filter element blockage status.

[0023] During the operation of the pump under test, the measurement and control unit synchronously collects signals from the first differential pressure sensor, the second differential pressure sensor, the pump inlet absolute pressure, the pump inlet temperature, the pump outlet pressure, the liquid ammonia mass flow rate, the pump speed, and the flow control valve opening according to a unified sampling period. The measurement and control unit writes a timestamp under the same clock reference for each sampled value and groups the sampled values ​​falling within the same sampling period into an operating data group. For sampled values ​​that are missing, exceed the range, have zero drift exceeding the set value, or have failed communication verification, the measurement and control unit assigns an anomaly mark. When the fluctuations in pump speed, liquid ammonia mass flow rate, and flow control valve opening are all below the corresponding stable threshold, the measurement and control unit establishes a steady-state window and filters and averages the sampled values ​​without anomaly marks within the steady-state window to reduce the impact of liquid ammonia flow pulsation on the judgment results.

[0024] When establishing the clogging judgment benchmark, after installing the clean filter element, the measurement and control unit collects the filter pressure difference under multiple combinations of liquid ammonia mass flow rate, pump inlet temperature, and pump speed to establish a clean reference pressure difference function. During operation, the measurement and control unit queries or calculates the liquid ammonia density and viscosity based on the liquid ammonia mass flow rate and pump inlet temperature in the operating data set, and uses the liquid ammonia density and viscosity to compensate the clean reference pressure difference function to obtain the current reference pressure difference. The measurement and control unit generates a filter element clogging characterization value based on the deviation of the measured pressure difference from the first differential pressure sensor relative to the current reference pressure difference.

[0025] The measurement and control unit calculates the sliding average value and the rate of change per unit time for the filter element clogging characteristics, and compares the sliding average value and the rate of change per unit time with the clogging warning threshold, clogging protection threshold, and clogging change rate threshold. If the sliding average value reaches the first warning threshold and multiple consecutive steady-state windows are met, or if the rate of change per unit time reaches the sudden increase threshold, the measurement and control unit determines it as a Level 1 warning; if the sliding average value reaches the second warning threshold, or if the Level 1 warning lasts for more than a set time, the measurement and control unit determines it as a Level 2 warning; if the sliding average value reaches the clogging protection threshold, the measurement and control unit determines it as a Level 3 protection. The pump pressure rise verification value output by the second differential pressure sensor is used to verify the above comparison results under operating conditions, avoiding misjudgments caused by changes in the opening of the regulating valve, changes in flow rate, or changes in the operating conditions of the measured pump.

[0026] To accommodate the easily vaporized nature of liquid ammonia, the monitoring and control unit also determines the subcooling margin or available NPSH based on the pump inlet absolute pressure and pump inlet temperature. When the pump inlet absolute pressure is lower than the sum of the saturation pressure corresponding to the pump inlet temperature and the safety pressure margin, the monitoring and control unit classifies this state as an inlet supply risk and raises the filter element clogging warning level by at least one level. When the difference between the pump pressure rise calibration value of the second differential pressure sensor and the pump outlet pressure and pump inlet absolute pressure exceeds the calibration threshold, the monitoring and control unit marks the differential pressure sensor or pressure sensor as abnormal and suspends the filter element clogging warning level upgrade triggered based on the pump pressure rise calibration value. This allows for the differentiation between actual filter element clogging, sensor malfunction, and liquid ammonia inlet supply risk.

[0027] The monitoring and control unit (MCU) outputs warning signals and executes protective actions based on the filter element clogging warning level. When the warning level is Level 1, the MCU outputs a filter element maintenance prompt and predicts the remaining operating time based on the changing trend of the filter element clogging indicator value. When the warning level is Level 2, the MCU increases the sampling frequency, limits the target speed of the tested pump or the target flow rate of liquid ammonia, and outputs a filter element replacement prompt. When the warning level is Level 3, the MCU sends a pump stop command to the tested pump, records the operating data set within a preset time period before the pump stop, and outputs a maintenance prompt prohibiting restart. After the filter element is replaced, the MCU re-acquires the filter differential pressure under low-speed operating conditions. Once it confirms that the filter element clogging indicator value is below the reset threshold, it removes the maintenance prompt prohibiting restart and updates the clean reference differential pressure function using the data from the replaced clean filter element.

[0028] In a preferred embodiment, a differential pressure sensor is used to measure the pressure difference between two measuring points. A physical diagram of the differential pressure sensor is attached. Figure 9 As shown. Compared to the method of using two independent pressure sensors to measure and then subtract the values, the differential pressure sensor can directly output the differential pressure signal, has higher differential pressure resolution, and is suitable for calculating the head of the pump under test and determining filter blockage. Two types of differential pressure measurements are set in the closed-loop circuit of the liquid ammonia pump: the differential pressure of the pump under test and the differential pressure of the filter. The second differential pressure sensor is connected between the pump inlet and outlet of the pump under test to directly measure the differential pressure. The obtained differential pressure signal is used as a pump pressure rise check quantity and for calculating the head of the pump under test.

[0029] A first differential pressure sensor is connected across both ends of the filter. This sensor acquires the filter's differential pressure and is used in calculating the filter element clogging characteristics. When the filter differential pressure increases, it indicates that the filter element may be clogged by contaminants, increasing the filter's flow resistance and potentially lowering the pump inlet absolute pressure, thus increasing the risk of cavitation in the tested pump. Therefore, the first differential pressure sensor is not only used for filter element maintenance assessment but also serves as a signal source for pump inlet safety protection.

[0030] The technical solution in this embodiment correlates the filter differential pressure with the liquid ammonia mass flow rate, pump inlet temperature, pump pressure rise verification amount, and available net positive suction head (NPSH). This enables accurate identification of the filter element clogging level, reduces the risk of false alarms and leakage alarms, and allows for timely execution of flow limiting, speed limiting, or pump shutdown protection, thereby improving the operational safety of the liquid ammonia pump and the reliability of test data.

[0031] In one embodiment, such as Figure 2 As shown, synchronously acquiring signals and obtaining a set of running data includes the following steps S21-S24: In step S21, the first differential pressure sensor, the second differential pressure sensor, the pressure sensor, the temperature sensor, the mass flow meter, the speed sensor, and the valve position feedback module are triggered to sample using the same clock pulse, and a timestamp is written for each sampled value. In step S22, the sampled values ​​whose timestamps fall within the same sampling period are aligned, and anomaly markers are added to sampled values ​​that are missing, out of range, have zero drift exceeding the set value, or have failed communication verification. In step S23, a steady-state window is established when the pump speed fluctuation, liquid ammonia mass flow rate fluctuation, and flow control valve opening fluctuation are all below the corresponding stable threshold. The sampled values ​​without anomaly markers within the steady-state window are filtered and averaged. In step S24, the filtered and averaged sampled values ​​are merged with the anomaly markers to form the running data group.

[0032] In one embodiment, the measurement and control unit is used to synchronously acquire measurement point signals in the closed-loop circulation circuit of the liquid ammonia pump. A first differential pressure sensor is connected across the filter, and a second differential pressure sensor is connected across the pump under test. A pressure sensor is arranged at the pump inlet and outlet, a temperature sensor is arranged at the pump inlet, a mass flow meter is arranged after the filter, a speed sensor is used to acquire the speed of the pump under test, and a valve position feedback module is used to acquire the opening degree of the flow regulating valve. The measurement and control unit triggers the above sensors and the valve position feedback module to sample with the same clock pulse, so that the filter differential pressure, the differential pressure of the pump under test, the absolute pressure at the pump inlet, the pump inlet temperature, the pump outlet pressure, the mass flow rate of liquid ammonia, the pump speed, and the opening degree of the flow regulating valve are all under the same time reference.

[0033] After obtaining the sampled values, the measurement and control unit writes a timestamp for each sampled value and merges the timestamps according to the sampling period. Sampled values ​​whose timestamps fall within the same sampling period are aligned into the same group of candidate data. When a sampled value is missing, exceeds the range, has zero-point drift exceeding the set value, or communication verification fails, the measurement and control unit adds an anomaly flag to that sampled value. The anomaly flag is not directly deleted from the sampled value, but is saved together with the sampled value for subsequent judgment of the sensor status, sampling link status, and the reliability of the filter blockage judgment result, thereby avoiding the incorrect upgrading of the filter blockage warning level due to an anomaly at a single measurement point.

[0034] The monitoring and control unit continuously monitors fluctuations in pump speed, liquid ammonia mass flow rate, and flow control valve opening. When all three fluctuations are below their corresponding stable thresholds, the monitoring and control unit establishes a steady-state window and filters and averages the sampled values ​​within the steady-state window that are not marked with anomalies. The filtering can employ moving average filtering, median filtering, or amplitude limiting filtering, and the averaging can employ arithmetic average or weighted average. The filtered and averaged sampled values ​​are then merged with the anomaly markers to form an operational data set. This operational data set serves as the data basis for calculating filter element blockage characterization values, pump pressure rise verification values, and filter element blockage early warning levels.

[0035] In one embodiment, such as Figure 3 As shown, the filter element clogging characterization value is obtained, including the following steps S31-S34: In step S31, after installing the clean filter element, the filtration pressure difference is collected under multiple combinations of liquid ammonia mass flow rate, pump inlet temperature and pump speed to establish a clean reference pressure difference function; In step S32, the liquid ammonia density and viscosity are queried or calculated based on the liquid ammonia mass flow rate and pump inlet temperature in the operating data group, and the clean reference pressure difference function is compensated with the liquid ammonia density and liquid ammonia viscosity to obtain the current reference pressure difference; In step S33, the deviation of the measured differential pressure of the first differential pressure sensor from the current reference differential pressure is used to generate a filter element blockage characterization value; In step S34, when no warning is triggered and the steady-state window continues to meet the set time, the clean reference pressure difference function is updated based on the measured pressure difference without anomaly markers within the steady-state window according to the update weight which is less than the set learning coefficient.

[0036] In one embodiment, after all filters are fitted with clean filter elements, the control unit controls the tested pump to operate under multiple combinations of liquid ammonia mass flow rate, pump inlet temperature, and pump speed, and collects the filtration differential pressure output by the first differential pressure sensor. The filters in the closed-loop circulation circuit of the liquid ammonia pump are used to protect the tested pump. The filtration differential pressure changes with the liquid ammonia mass flow rate, liquid ammonia density, and liquid ammonia viscosity. Therefore, the control unit does not directly use a fixed differential pressure as the basis for clogging judgment. Instead, it establishes a mapping relationship between the filtration differential pressure obtained under clean filter element conditions and the corresponding liquid ammonia mass flow rate, pump inlet temperature, and pump speed, forming a clean reference differential pressure function.

[0037] During the operation of the pump under test, the measurement and control unit reads the liquid ammonia mass flow rate and pump inlet temperature from the operating data set, and queries or calculates the liquid ammonia density and viscosity based on the pump inlet temperature. The measurement and control unit uses the liquid ammonia density and viscosity to compensate for the clean reference pressure difference function to obtain the current reference pressure difference. The measurement and control unit compares the measured pressure difference of the first differential pressure sensor with the current reference pressure difference, and generates a filter element clogging characterization value based on the deviation between the two. The deviation can be a pressure difference value, a pressure difference ratio, or a dimensionless value after normalization.

[0038] To avoid distortion of the clean reference differential pressure function due to batch differences in filter cartridges, differences in pipeline assembly, or slight drift during long-term operation, the monitoring and control unit performs a small update to the clean reference differential pressure function when no warning is triggered and the steady-state window continuously meets the set time. This small update uses an update weight less than the set learning coefficient and updates the clean reference differential pressure function based on the measured differential pressure within the steady-state window without any anomaly markers. If the filter cartridge clogging characterization value reaches the warning threshold, the monitoring and control unit stops updating the corresponding clean reference differential pressure function. Therefore, the clogging characterization value can reflect the true degree of filter cartridge contamination and reduce misjudgments caused by changes in flow rate, temperature, or liquid ammonia properties.

[0039] In one embodiment, such as Figure 4 As shown, determining the filter clogging warning level includes the following steps S41-S44: In step S41, the sliding average value and the rate of change per unit time are calculated for the filter element clogging characterization value; In step S42, when the moving average reaches the first warning threshold and N consecutive steady-state windows are established, or when the rate of change per unit time reaches the sudden increase threshold, it is determined to be a first-level warning, where N is an integer not less than 2; In step S43, when the sliding average value reaches the second warning threshold, or when the duration of the first-level warning exceeds the set time, it is determined to be a second-level warning; In step S44, when the sliding average value reaches the clogging protection threshold, or the filter element clogging characterization value reaches the second warning threshold and the subcooling margin or available cavitation margin is lower than the protection margin, it is determined to be a level three protection.

[0040] In one embodiment, the monitoring and control unit determines the warning level based on the filter element blockage characterization value formed within the steady-state window. Since the closed-loop circulation of the liquid ammonia pump requires the pump inlet to maintain single-phase subcooled liquid ammonia, an abnormal increase in the filter pressure difference not only indicates that the filter element may be blocked, but may also reduce the absolute pressure at the pump inlet and affect the subcooling margin or available net positive suction head (NPSH).

[0041] The measurement and control unit compares the sliding average value with the first warning threshold, the second warning threshold, and the blockage protection threshold, and also compares the rate of change per unit time with the surge threshold. When the sliding average value reaches the first warning threshold and the judgment condition is met for N consecutive steady-state windows, or when the rate of change per unit time reaches the surge threshold, the measurement and control unit determines the filter element blockage warning level as Level 1, where N is an integer not less than 2. When the sliding average value reaches the second warning threshold, or when the Level 1 warning duration exceeds the set time, the measurement and control unit determines the filter element blockage warning level as Level 2. This judgment can take into account both slow and sudden blockage of the filter element, reducing misjudgments caused by instantaneous pressure fluctuations.

[0042] When the sliding average value reaches the clogging protection threshold, the measurement and control unit determines the filter element clogging warning level to Level 3 protection. If the filter element clogging indicator value reaches the second warning threshold, and the subcooling margin or available NPSH is lower than the protection margin, the measurement and control unit still determines the filter element clogging warning level to Level 3 protection, even if the sliding average value has not yet reached the clogging protection threshold. Level 3 protection indicates a high risk of cavitation at the inlet of the tested pump or that filter element clogging has affected safe operation; based on this, the measurement and control unit triggers protective actions such as flow limiting, speed limiting, or pump shutdown.

[0043] In one embodiment, such as Figure 5 As shown, before determining the filter clogging warning level, the following steps S51-S53 are included: In step S51, the trend of the measured differential pressure of the first differential pressure sensor changing with the square of the liquid ammonia mass flow rate is compared with the reference trend determined by the clean reference differential pressure function. If the deviation of the change ratio between the measured trend and the reference trend is not greater than the operating condition verification threshold, and the filter element blockage characterization value has not reached the first warning threshold, then the current filter element blockage warning level is maintained. In step S52, the pump pressure rise verification value of the second differential pressure sensor is compared with the difference between the pump outlet pressure and the pump inlet absolute pressure. If the deviation exceeds the verification threshold, the differential pressure sensor or pressure sensor is marked as abnormal, and the filter clogging warning level upgrade triggered based on the pump pressure rise verification value is suspended. In step S53, when the absolute pressure at the pump inlet is lower than the lower limit of the inlet pressure, the abnormality is classified as an inlet liquid supply risk, and the filter element blockage warning level is raised by at least one level. The lower limit of the inlet pressure is the sum of the saturation pressure corresponding to the pump inlet temperature and the safety pressure margin.

[0044] In one embodiment, before determining the filter element clogging warning level, the measurement and control unit performs operational condition verification on the filter differential pressure and the pressure rise of the tested pump. In the closed-loop circulation circuit of the liquid ammonia pump, the filter differential pressure is significantly affected by the liquid ammonia mass flow rate. When the liquid ammonia mass flow rate increases, the flow resistance at the filter usually increases with the square of the liquid ammonia mass flow rate. Based on this characteristic, the measurement and control unit compares the trend of the measured differential pressure of the first differential pressure sensor changing with the square of the liquid ammonia mass flow rate with the current reference differential pressure. If the measured differential pressure of the first differential pressure sensor increases proportionally with the square of the liquid ammonia mass flow rate, and the filter element clogging indicator value does not reach the first warning threshold, the measurement and control unit determines that the increase in differential pressure mainly comes from changes in flow conditions and maintains the current filter element clogging warning level. This process can prevent normal increases in differential pressure caused by changes in the opening degree of the flow regulating valve or changes in the speed of the tested pump from being misjudged as filter element clogging.

[0045] The measurement and control unit also compares the pump pressure rise verification value output by the second differential pressure sensor with the difference between the pump outlet pressure and the pump inlet absolute pressure. The second differential pressure sensor is directly connected across the two ends of the pump under test. The difference between the pump outlet pressure and the pump inlet absolute pressure is the indirectly obtained pump pressure rise. The two types of pressure rises should be consistent or within the allowable deviation range within the same steady-state window. If the deviation between the pump pressure rise verification value and the difference exceeds the verification threshold, the measurement and control unit marks the differential pressure sensor or pressure sensor as abnormal and suspends the upgrade of the filter element clogging warning level triggered based on the pump pressure rise verification value. This verification does not directly negate the preliminary judgment result formed by the filter element clogging characterization value, but incorporates the reliability of the measurement point into the filter element clogging warning level judgment to prevent measurement point drift, range abnormality, or sampling link abnormality from causing the filter element clogging warning level to be incorrectly upgraded.

[0046] The monitoring and control unit determines the lower limit of the inlet pressure based on the absolute pressure and temperature at the pump inlet. The lower limit is the sum of the saturation pressure corresponding to the pump inlet temperature and the safety pressure margin. When the absolute pressure at the pump inlet is lower than the lower limit, it indicates insufficient subcooling of the liquid ammonia at the pump inlet, posing a risk of vaporization or cavitation. The monitoring and control unit classifies this condition as an inlet supply risk and raises the filter element clogging warning level by at least one level. After the filter element clogging warning level is raised, the monitoring and control unit continues to combine the filter element clogging characteristic value and the pump pressure rise verification value to determine whether to trigger flow restriction, speed limit, or pump shutdown protection. This implementation method can simultaneously distinguish between filter element clogging, changes in flow conditions, abnormal measurement points, and inlet supply risk.

[0047] In one embodiment, such as Figure 6 As shown, the protective action is executed according to the filter clogging warning level, including the following steps S61-S64: In step S61, when the filter element clogging warning level is Level 1, a filter element maintenance prompt is output to maintain the operation of the tested pump, and the remaining operating time to reach Level 2 or Level 3 protection is predicted based on the changing trend of the filter element clogging characterization value. In step S62, when the filter element clogging warning level is level two, the sampling frequency is increased, the target speed of the pump under test or the target flow rate of liquid ammonia is limited, and a filter element replacement prompt is output. In step S63, when the filter element clogging warning level is level three protection, a pump stop command is sent to the pump under test, the operating data set within the preset time period before the pump stop is recorded, and a maintenance prompt prohibiting restart is output. In step S64, after the filter element is replaced, the filtration differential pressure is re-acquired under low-speed operation. If the filter element blockage characterization value is lower than the reset threshold, the maintenance prompt prohibiting restart is lifted, and the data of the replaced clean filter element is used to update the clean reference differential pressure function.

[0048] In one embodiment, the monitoring and control unit (PCU) executes protective actions based on the filter element clogging warning level. When the filter element clogging warning level is Level 1, the PCU outputs a filter element maintenance prompt and maintains the operation of the tested pump. The PCU fits the changing trend of the filter element clogging characteristic value within multiple steady-state windows and predicts the remaining operating time before the filter element clogging characteristic value reaches Level 2 warning or Level 3 protection based on the changing trend. This remaining operating time is displayed or recorded along with the filter element maintenance prompt to remind operators to arrange filter element inspection.

[0049] When the filter element clogging warning level is Level 2, the monitoring and control unit increases the sampling frequency of the first differential pressure sensor, second differential pressure sensor, pressure sensor, temperature sensor, mass flow meter, speed sensor, and valve position feedback module, and limits the target speed of the tested pump or the target flow rate of liquid ammonia. While limiting the target speed of the tested pump or the target flow rate of liquid ammonia, the monitoring and control unit continues to collect operating data sets and determines whether the filter element clogging warning level should continue to rise based on the filter element clogging characterization value and the pump pressure rise verification value. The monitoring and control unit outputs a filter element replacement prompt, allowing the tested pump to operate under restricted conditions for a short period, reducing the possibility of increased cavitation risk due to filter element clogging.

[0050] When the filter element clogging warning level is Level 3, the control unit sends a pump stop command to the pump under test and records the operating data set, filter element clogging characterization value, pump pressure rise verification amount, and filter element clogging warning level for the preset time period before pump stoppage. The control unit outputs a maintenance prompt prohibiting restart until the filter element is replaced. After filter element replacement, the control unit controls the pump under test to re-acquire the filter differential pressure under low-speed operation. When the filter element clogging characterization value is lower than the reset threshold, the control unit removes the maintenance prompt prohibiting restart and uses the data from the replaced clean filter element to update the clean reference differential pressure function.

[0051] In one embodiment, Figure 7 This is a block diagram illustrating a liquid ammonia pump filtration and differential pressure monitoring protection device with blockage warning according to an exemplary embodiment. Figure 7 The liquid ammonia pump filtration and differential pressure monitoring and protection device with blockage warning is applied to a closed-loop circulation circuit of a liquid ammonia pump. The closed-loop circulation circuit of the liquid ammonia pump is provided with a liquid reservoir, a filter, a pump under test, a mass flow meter, a flow regulating valve and a heat exchanger along the liquid ammonia flow direction. A first differential pressure sensor is connected across both ends of the filter, and a second differential pressure sensor is connected across both ends of the pump under test. The device is characterized by including a data acquisition module 71, a calculation module 72, a determination module 73 and an execution module 74.

[0052] The acquisition module 71 is used to simultaneously acquire signals from the first differential pressure sensor, the second differential pressure sensor, the absolute pressure at the pump inlet, the pump inlet temperature, the pump outlet pressure, the mass flow rate of liquid ammonia, the pump speed, and the opening of the flow regulating valve during the operation of the pump under test, so as to obtain a set of operating data at the same sampling time. The calculation module 72 is used to correlate the first differential pressure sensor signal in the operating data group with the liquid ammonia mass flow rate, pump inlet temperature and preset clean filter element reference differential pressure to obtain the filter element blockage characterization value, and use the second differential pressure sensor signal in the operating data group as the pump pressure rise verification quantity; The determining module 73 is used to compare the filter element clogging characterization value with the corresponding clogging warning threshold, clogging protection threshold and clogging change rate threshold, and to use the pump pressure rise verification amount to perform working condition verification on the comparison result. Then, combined with the subcooling margin or available cavitation margin obtained from the pump inlet absolute pressure and pump inlet temperature, the filter element clogging warning level is determined. The execution module 74 is used to output a warning signal based on the filter element clogging warning level, and when the filter element clogging warning level reaches the protection condition, to perform at least one of the following protective actions: reducing the target flow rate, limiting the pump speed, stopping the pump, and prompting to replace the filter element. At the same time, it stores the operating data set before and after the trigger, the filter element clogging characterization value, and the filter element clogging warning level.

[0053] The block diagram of the liquid ammonia pump filtration and differential pressure monitoring and protection device with blockage warning included the acquisition module 71, the calculation module 72, the determination module 73, and the execution module 74, which are controlled to execute the liquid ammonia pump filtration and differential pressure monitoring and protection method with blockage warning described in any of the above embodiments.

[0054] like Figure 8 As shown, the present invention provides an electronic device 800, which includes: a communication interface, a processor 801, and a memory 802; The memory 802 stores program instructions. When executed by the processor 801, which is connected to the memory 802 via the communication interface, the program instructions are applied to the closed-loop circulation of the liquid ammonia pump. During the operation of the pump under test, the measurement and control unit synchronously collects the filter differential pressure, the pump differential pressure, the pump inlet absolute pressure, the pump inlet temperature, the pump outlet pressure, the liquid ammonia mass flow rate, the pump speed, and the flow regulating valve opening, forming a set of operating data at the same sampling time. The filter differential pressure signal is correlated with the liquid ammonia mass flow rate, the pump inlet temperature, and the preset clean filter element reference differential pressure to calculate the filter element clogging characterization value. Combined with the pump pressure rise check amount, the subcooling margin, or the available NPSH, the filter element clogging warning level is determined, and then a warning signal is output and corresponding protective actions are executed.

[0055] This invention provides a computer-readable storage medium storing computer program instructions. When executed by a processor, these instructions are applied to the closed-loop circulation circuit of a liquid ammonia pump. During the operation of the pump under test, a measurement and control unit synchronously collects the filter differential pressure, the pump differential pressure, the pump inlet absolute pressure, the pump inlet temperature, the pump outlet pressure, the liquid ammonia mass flow rate, the pump speed, and the flow regulating valve opening, forming a set of operating data at the same sampling time. The filter differential pressure signal is correlated with the liquid ammonia mass flow rate, the pump inlet temperature, and the preset clean filter element reference differential pressure to calculate the filter element clogging characterization value. Combined with the pump pressure rise check, subcooling margin, or available NPSH, the filter element clogging warning level is determined, and then a warning signal is output and corresponding protective actions are executed.

[0056] It should be understood that the specific features, operations, and details described above regarding the method of the present invention can also be similarly applied to the apparatus and system of the present invention, or vice versa. Furthermore, each step of the method of the present invention described above can be performed by a corresponding component or unit of the apparatus or system of the present invention.

[0057] It should be understood that the various modules / units of the device of the present invention can be implemented wholly or partially through software, hardware, firmware, or a combination thereof. Each module / unit can be embedded in the processor of a computer device in hardware or firmware form or independent of the processor, or it can be stored in the memory of a computer device in software form for the processor to call to execute the operation of each module / unit. Each module / unit can be implemented as an independent component or module, or two or more modules / units can be implemented as a single component or module.

[0058] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores computer instructions executable by the processor, which, when executed by the processor, instruct the processor to perform steps of the methods of embodiments of the present invention. The computer device can be broadly categorized as a server, terminal, or any other electronic device with the necessary computing and / or processing capabilities. In one embodiment, the computer device may include a processor, memory, network interface, communication interface, etc., connected via a system bus. The processor of the computer device can be used to provide the necessary computing, processing, and / or control capabilities. The memory of the computer device may include a non-volatile storage medium and internal memory. The non-volatile storage medium may store an operating system, computer programs, etc. The internal memory can provide an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface and communication interface of the computer device can be used to connect and communicate with external devices via a network. When the computer program is executed by the processor, it performs the steps of the methods of the present invention.

[0059] This invention can be implemented as a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, causes the steps of the methods of embodiments of the invention to be performed. In one embodiment, the computer program is distributed across multiple network-coupled computer devices or processors, such that the computer program is stored, accessed, and executed in a distributed manner by one or more computer devices or processors. A single method step / operation, or two or more method steps / operations, may be executed by a single computer device or processor or by two or more computer devices or processors. One or more method steps / operations may be executed by one or more computer devices or processors, and one or more other method steps / operations may be executed by one or more other computer devices or processors. One or more computer devices or processors may execute a single method step / operation, or execute two or more method steps / operations.

[0060] It will be understood by those skilled in the art that the method steps of the present invention can be performed by a computer program instructing related hardware, such as a computer device or processor. The computer program may be stored in a non-transitory computer-readable storage medium, and its execution causes the steps of the present invention to be performed. Depending on the context, any references herein to memory, storage, databases, or other media may include non-volatile and / or volatile memory. Examples of non-volatile memory include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, etc. Examples of volatile memory include random access memory (RAM), external cache memory, etc.

[0061] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning, executed by a measurement and control unit, applied to a closed-loop circulation circuit of a liquid ammonia pump, wherein the closed-loop circulation circuit of the liquid ammonia pump is provided with a liquid reservoir, a filter, a pump under test, a mass flow meter, a flow regulating valve, and a heat exchanger along the liquid ammonia flow direction, wherein a first differential pressure sensor is connected across the two ends of the filter, and a second differential pressure sensor is connected across the two ends of the pump under test, characterized in that... include: During the operation of the pump under test, signals from the first differential pressure sensor, the second differential pressure sensor, the absolute pressure at the pump inlet, the pump inlet temperature, the pump outlet pressure, the mass flow rate of liquid ammonia, the pump speed, and the opening of the flow regulating valve are collected simultaneously to obtain a set of operating data at the same sampling time. The first differential pressure sensor signal in the operating data set is correlated with the liquid ammonia mass flow rate, pump inlet temperature and preset clean filter element reference differential pressure to obtain the filter element blockage characterization value, and the second differential pressure sensor signal in the operating data set is used as the pump pressure rise verification quantity. The filter element clogging characterization value is compared with the corresponding clogging warning threshold, clogging protection threshold and clogging change rate threshold. The comparison result is then checked for operating conditions using the pump pressure rise verification value. Finally, the subcooling margin or available cavitation margin obtained from the pump inlet absolute pressure and pump inlet temperature is combined to determine the filter element clogging warning level. Based on the filter element clogging warning level, an early warning signal is output, and when the filter element clogging warning level reaches the protection condition, at least one of the following protective actions is executed: reducing the target flow rate, limiting the pump speed, stopping the pump, and prompting to replace the filter element. At the same time, the operating data set before and after the trigger, the filter element clogging characterization value, and the filter element clogging warning level are stored.

2. The method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning as described in claim 1, characterized in that, Synchronously acquire signals and obtain a set of operational data, including: The first differential pressure sensor, the second differential pressure sensor, the pressure sensor, the temperature sensor, the mass flow meter, the speed sensor, and the valve position feedback module are triggered to sample using the same clock pulse, and a timestamp is written for each sampled value. Align the sampled values ​​whose timestamps fall within the same sampling period, and add an anomaly flag to sampled values ​​that are missing, out of range, have zero drift exceeding the set value, or have failed communication verification. When the fluctuations in pump speed, liquid ammonia mass flow rate, and flow control valve opening are all below the corresponding stable threshold, a steady-state window is established, and the sampled values ​​without anomaly markers within the steady-state window are filtered and averaged. The filtered and averaged sampled values ​​are combined with the anomaly markers to form the running data group.

3. The method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning as described in claim 1, characterized in that, The filter element clogging characterization values ​​are obtained, including: After installing the clean filter element, the filtration pressure difference was collected under multiple combinations of liquid ammonia mass flow rate, pump inlet temperature and pump speed to establish a clean reference pressure difference function. The current operating conditions are determined based on the liquid ammonia mass flow rate, pump inlet temperature, and pump speed in the operating data group. The liquid ammonia density and viscosity are queried or calculated, and the clean reference pressure difference function is compensated with the liquid ammonia density and viscosity to obtain the current reference pressure difference. The deviation of the measured differential pressure from the first differential pressure sensor from the current reference differential pressure is used to generate a filter element clogging characterization value; If no warning is triggered and the steady-state window continues to meet the set time, the clean reference pressure difference function is updated based on the measured pressure difference without anomaly markers within the steady-state window, according to an update weight less than the set learning coefficient.

4. The liquid ammonia pump filtration and differential pressure monitoring protection method with blockage early warning as described in claim 3, characterized in that, Determine the filter clogging warning level, including: Calculate the sliding average value and the rate of change per unit time for the filter element clogging characterization values; When the sliding average value reaches the first warning threshold and the condition is met for N consecutive steady-state windows, or when the rate of change per unit time reaches the sudden increase threshold, the filter blockage warning level is determined to be a Level 1 warning, where N is an integer not less than 2. When the sliding average value reaches the second warning threshold, or when the duration of the first-level warning exceeds the set time, the filter clogging warning level is determined to be a second-level warning. When the sliding average value reaches the clogging protection threshold, or the filter element clogging characterization value reaches the second warning threshold and the subcooling margin or available NPSH is lower than the corresponding protection margin, the filter element clogging warning level is determined to be Level 3 protection, wherein the first warning threshold is less than the second warning threshold, and the second warning threshold is less than the clogging protection threshold.

5. The liquid ammonia pump filtration and differential pressure monitoring protection method with blockage early warning as described in claim 4, characterized in that, Before determining the filter clogging warning level, the following should be included: The measured trend of the actual pressure difference of the first differential pressure sensor changing with the square of the liquid ammonia mass flow rate is compared with the reference trend determined by the clean reference differential pressure function. If the deviation of the change ratio between the measured trend and the reference trend is not greater than the operating condition verification threshold, and the filter element blockage characterization value has not reached the first warning threshold, then the current filter element blockage warning level is maintained. The pump pressure rise calibration value of the second differential pressure sensor is compared with the difference between the pump outlet pressure and the pump inlet absolute pressure after the unified pressure reference. If the deviation exceeds the calibration threshold, an abnormal mark is added to at least one of the second differential pressure sensor, the pump inlet absolute pressure sensor or the pump outlet pressure sensor, and the filter clogging warning level upgrade triggered based on the pump pressure rise calibration value is suspended. When the absolute pressure at the pump inlet is lower than the lower limit of the inlet pressure, the current operating condition is judged as a risk to the inlet liquid supply, and the filter element blockage warning level is raised by at least one level. The lower limit of the inlet pressure is the sum of the saturation pressure corresponding to the pump inlet temperature and the safety pressure margin.

6. The method for filtering and differential pressure monitoring and protection of a liquid ammonia pump with blockage early warning as described in claim 5, characterized in that, Based on the filter clogging warning level, protective actions are executed, including: When the filter element clogging warning level is Level 1, a filter element maintenance prompt is output to maintain the operation of the tested pump, and the remaining operating time to reach Level 2 or Level 3 protection is predicted based on the changing trend of the filter element clogging characterization value. When the filter element clogging warning level is Level II, the sampling frequency of the first differential pressure sensor, the second differential pressure sensor, the pump inlet absolute pressure sensor, the pump outlet pressure sensor, the pump inlet temperature sensor, the mass flow meter, the speed sensor, and the valve position feedback module is increased, the target speed of the tested pump or the target flow rate of liquid ammonia is limited, and a filter element replacement prompt is output. When the filter element clogging warning level is level three protection, a pump stop command is sent to the pump under test, and the operating data set, filter element clogging characterization value, pump pressure rise verification amount and filter element clogging warning level within the preset time period before the pump stop are recorded, and a maintenance prompt prohibiting restart is output. After the filter element is replaced, the filtration differential pressure is re-acquired under low-speed operation. If the filter element blockage indicator value is lower than the reset threshold, the maintenance prompt prohibiting restart is lifted, and the data of the replaced clean filter element is used to update the clean reference differential pressure function.

7. A liquid ammonia pump filtration and differential pressure monitoring and protection device with blockage early warning, applied to a closed-loop circulation circuit of a liquid ammonia pump, wherein the closed-loop circulation circuit of the liquid ammonia pump is provided with a liquid reservoir, a filter, a pump under test, a mass flow meter, a flow regulating valve and a heat exchanger along the liquid ammonia flow direction, wherein a first differential pressure sensor is connected across both ends of the filter, and a second differential pressure sensor is connected across both ends of the pump under test, characterized in that, include: The acquisition module is used to simultaneously acquire signals from the first differential pressure sensor, the second differential pressure sensor, the absolute pressure at the pump inlet, the pump inlet temperature, the pump outlet pressure, the mass flow rate of liquid ammonia, the pump speed, and the opening of the flow regulating valve during the operation of the pump under test, so as to obtain a set of operating data at the same sampling time. The calculation module is used to correlate the first differential pressure sensor signal in the operating data group with the liquid ammonia mass flow rate, pump inlet temperature and preset clean filter element reference differential pressure to obtain the filter element blockage characterization value, and use the second differential pressure sensor signal in the operating data group as the pump pressure rise verification quantity; The determination module is used to compare the filter element clogging characterization value with the corresponding clogging warning threshold, clogging protection threshold and clogging change rate threshold, and to use the pump pressure rise verification amount to perform working condition verification on the comparison result. Then, combined with the subcooling margin or available cavitation margin obtained from the pump inlet absolute pressure and pump inlet temperature, the filter element clogging warning level is determined. The execution module is used to output a warning signal based on the filter element clogging warning level, and when the filter element clogging warning level reaches the protection condition, execute at least one of the following protective actions: reducing the target flow rate, limiting the pump speed, stopping the pump, and prompting to replace the filter element. At the same time, it stores the operating data set before and after the trigger, the filter element clogging characterization value, and the filter element clogging warning level.

8. The liquid ammonia pump filtration and differential pressure monitoring protection device with blockage early warning as described in claim 7, characterized in that: The acquisition module, the calculation module, the determination module, and the execution module are controlled to execute the liquid ammonia pump filtration and differential pressure monitoring protection method with blockage early warning as described in any one of claims 2 to 6.

9. An electronic device, characterized in that, include: Communication interface, processor, memory; The memory is used to store program instructions, which, when executed by the processor that is communicatively connected to the memory via the communication interface, enable the electronic device to implement the liquid ammonia pump filtration and differential pressure monitoring protection method with blockage warning as described in any one of claims 1 to 6.

10. A computer-readable storage medium having program instructions stored thereon, characterized in that, When the program instructions are executed by a computer, the computer implements the liquid ammonia pump filtration and differential pressure monitoring protection method with blockage warning as described in any one of claims 1 to 6.

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