Real-time measurement method for shaft temperature of centrifugal pump

Abstract

The invention discloses a real-time measurement method for the shaft temperature of a centrifugal pump. Comprising the following steps that at least two infrared temperature sensors are installed on a support independent of the centrifugal pump; taking the temperature measured by each infrared temperature sensor as at least two infrared channels; a fluorescent coating is formed on the end face of the centrifugal pump shaft through a laser cladding process, and the surface temperature of a shaft body is calculated according to the fluorescence lifetime and serves as a fluorescent channel to participate in temperature comparison of a monitoring system; an ultrasonic transducer is attached to the outside of a centrifugal pump bearing seat, the environment temperature Tacoustic is obtained through the ultrasonic transducer, and the environment temperature Tacoustic serves as an ultrasonic channel and is subjected to cross validation with an infrared channel; the integrity of output signals of each channel is detected in real time through a failure self-diagnosis module; a dynamic temperature threshold value is determined through a dynamic threshold value calculation module configured by the monitoring system, and meanwhile, the measured temperatures of the infrared temperature sensors are compared through a temperature comparison module; and on the basis of the comparison result and the dynamic temperature threshold value, real-time monitoring, alarming or shutdown control of the shaft temperature of the centrifugal pump is achieved.

Description

Technical Field

[0001] This invention relates to a method for real-time measurement of the shaft temperature of a centrifugal pump, belonging to the field of centrifugal pump shaft temperature measurement methods. Background Technology

[0002] A centrifugal pump is a device that uses centrifugal force to transport liquids, commonly used in industry and construction. Its core principle is to transfer energy to the liquid through the high-speed rotation of the impeller, thereby achieving liquid transport. Overheating of the bearings is a common fault in centrifugal pump operation; if not addressed promptly, it can lead to bearing burnout, motor damage, and even production shutdown.

[0003] Existing centrifugal pump shaft temperature measurement technology mainly involves operators periodically using handheld thermometers (such as infrared thermometers) to measure the surface temperature of the pump casing, bearings, and other components. This method is not real-time and cannot continuously monitor temperature changes related to bearings and shafts in real time, thus failing to detect anomalies promptly. It relies on manual labor, and the external surface temperature cannot accurately reflect the true temperature of critical internal components. Summary of the Invention

[0004] The purpose of this invention is to provide a real-time measurement method for the shaft temperature of a centrifugal pump, which addresses the aforementioned problems and overcomes the shortcomings of existing manual temperature measurement methods in terms of safety and real-time performance. It can also effectively monitor the temperature related to the operating status of the bearing and shaft.

[0005] The technical solution adopted in this invention is as follows: A method for real-time measurement of the shaft temperature of a centrifugal pump includes the following steps: Step 1: Install at least two infrared temperature sensors on a bracket separate from the centrifugal pump; Step 2: Connect the signal lines of each infrared temperature sensor to the corresponding temperature transmitter, and then connect the temperature transmitter to the monitoring system to obtain the temperature T_IR measured by each infrared temperature sensor, which serves as at least two infrared channels. Step 3: A fluorescent coating is formed on the end face of the centrifugal pump shaft using a laser cladding process. The fluorescence lifetime of the fluorescent coating is measured using a laser-PMT component. The surface temperature T_fluoro of the shaft body is calculated based on the fluorescence lifetime. T_fluoro is used as a fluorescence channel and is used in the temperature comparison of the monitoring system. Step 4: Attach an ultrasonic transducer to the outside of the centrifugal pump bearing housing, measure the ultrasonic echo transit time Δt through the ultrasonic transducer, calculate the sound velocity v(T), and calculate the ambient temperature T_acoustic based on the sound velocity v(T), which is used as the ultrasonic channel and cross-validated with the infrared channel. Step 5: Detect the integrity of the output signals of each channel in real time through the failure self-diagnosis module; Step 6: Determine the dynamic temperature threshold through the dynamic threshold calculation module, and compare the measured temperatures of each infrared temperature sensor through the temperature comparison module. Step 7: Based on the comparison results and dynamic temperature threshold, realize real-time monitoring, alarm or shutdown control of centrifugal pump shaft temperature.

[0006] Infrared temperature sensors can measure temperature without contact with the object being measured, making them suitable for applications such as bearings in safety inspections. They can respond to temperature changes within milliseconds, enabling dynamic temperature capture. Comparison of data from at least two channels under identical conditions allows for timely detection of sensor anomalies, ensuring reliable and stable data and eliminating errors caused by individual data failures. Averaging multiple data points effectively reduces errors. If one sensor malfunctions, other sensors can continue measurement, ensuring continuity. Accurate temperature measurement is achieved by transmitting excitation light to a rare-earth-doped fluorescent material, exciting it to emit characteristic fluorescence, and then transmitting the fluorescence signal back to the detector via optical fiber. Ultrasonic waves, whose propagation speed depends on the density and temperature of the medium and is unaffected by external contaminants or corrosive media, maintain stability even under high temperature and pressure. Different temperature measurement methods are used to determine the accuracy of infrared temperature data, improving measurement precision. Data validity is also assessed to prevent invalid or erroneous data from affecting subsequent analysis. Finally, the system determines whether the temperature exceeds a threshold and takes appropriate action.

[0007] Alternatively, in step 1, the at least two infrared temperature sensors are identical in model, range, and optical parameters, and are mounted side by side on the same independent bracket, with the probes of each infrared temperature sensor aimed at the same measurement area of ​​the centrifugal pump bearing.

[0008] Alternatively, in step 2, each infrared temperature sensor is connected to its corresponding temperature transmitter via an independent cable, forming at least two physically isolated signal channels.

[0009] Alternatively, in step 5, the failure self-diagnosis module performs real-time detection of the integrity of the input signals of each temperature signal channel. The integrity of the input signals includes signal disconnection, signal short circuit, signal over-range, and signal freeze. If a channel signal is determined to be faulty, the channel is reported as invalid, and the effective channel continues to be monitored.

[0010] Alternatively, in step 6, the specific calculation steps of the dynamic threshold calculation module are as follows: Step 61: Collect real-time operating data of the centrifugal pump, including inlet pressure P1, outlet valve position θ, flow rate Q, motor current I, and ambient temperature T_amb. Step 62: Input the collected real-time data into the Transformer model and output the expected temperature T_expected and standard deviation σ; Step 63: Calculate the dynamic threshold using the formula T_threshold=T_expected+2σ+n℃; if the system triggers sensor cleaning or channel weight reduction operation, automatically recalculate the standard deviation σ to update the dynamic temperature threshold T_threshold. Step 64: Calculate the temperature difference T_IR between any two infrared temperature sensors in real time. If the temperature difference ΔT > ΔT_threshold and continues for t3, output a sensor abnormality alarm and automatically switch to single-channel mode to continue monitoring with a higher value or average value without triggering a shutdown. Step 65: Use T_acoustic to cross-validate with T_IR of each infrared temperature sensor. When a T_IR and T_acoustic are out of tolerance and last for several seconds, trigger an abnormal alarm for that infrared temperature sensor. Step 66: Set the temperature rise rate threshold. If the measured temperature rise rate of the centrifugal pump shaft is greater than the temperature rise rate threshold, the shutdown delay will be shortened.

[0011] Alternatively, in step 64, when both T_fluoro and T_acoustic are present, the differences |T_IR–T_fluoro|, |T_IR–T_acoustic|, and |T_fluoro–T_acoustic| between the infrared channel T_IR, the fluorescence channel T_fluoro, and the ultrasonic channel T_acoustic are calculated; any two sets exceeding the tolerance ΔT_threshold will only trigger an alarm without stopping the machine; the original "single-channel mode" is extended to the "multi-channel weighted average" mode.

[0012] Alternatively, in step 65, if the difference between the infrared channel and T_acoustic is ΔT_IR_valid and lasts for several seconds, then the sensor drift alarm is triggered first, the shutdown is not triggered, and the lens ultrasonic cleaning is started.

[0013] Available for selection An ultrasonic transducer is integrated inside the lens cover of the infrared temperature sensor. When the sensor malfunctions and alarms, the edge gateway sends a cleaning command to the ultrasonic transducer to control its operation. After cleaning, wait a few seconds and re-acquire the temperature measured by the infrared temperature sensor. If the difference is still greater than ΔT_IR_valid, the weight of the temperature measured by the infrared temperature sensor is reduced, and the system switches to T_acoustic as the main channel. At the same time, the system reports suspected sensor contamination to the monitoring system.

[0014] Alternatively, in step 66, The temperature rise rate is calculated using T_fluoro first; if T_fluoro fails, the calculation of the temperature rise rate is reversed to the measurement temperature of the infrared temperature sensor in step 1.

[0015] Alternatively, step 7 may include: Step 71: When the infrared temperature sensor detects that the temperature exceeds the dynamic threshold T_threshold and the duration reaches t1, the monitoring system triggers an alarm. Step 72: After the alarm, if the temperature measured by the infrared temperature sensor is still higher than the dynamic threshold T_threshold, and the temperature difference between the effective signal channels of the two infrared temperature sensors is less than the preset temperature difference threshold ΔT_threshold, and the duration reaches t2, where t1 < t2, the monitoring system triggers a shutdown; if the temperature difference between the two effective signal channels is greater than or equal to ΔT_threshold within t2, it is determined that the sensor is abnormal, and the shutdown command is blocked.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: This invention provides a real-time measurement method for the shaft temperature of a centrifugal pump, featuring multi-layer temperature sensing (shaft body-bearing-cage), redundant cross-validation, AI perturbation filtering, sensor self-healing calibration, and acoustic-optical multi-physical quantity fusion. It can monitor the actual operating temperature of these components in real time and continuously. Real-time monitoring and alarm functions enable operators to promptly detect abnormal temperature trends and intervene in the early stages of faults, transforming passive maintenance into proactive maintenance and preventing sudden failures. Furthermore, the real-time recorded temperature data can be used for fault diagnosis, performance evaluation, and maintenance plan development. This solution incorporates a triple anti-error measure of "redundant comparison + delay filtering + failure self-diagnosis" to ensure neither false alarms nor missed alarms. The true temperature value can be traced through historical processing data and workflows. Fault identification and subsequent processing are incorporated into the automatic sensor judgment process, enabling fault location and self-healing. Moreover, the sensor and bearing used in this solution are entirely passive / non-contact, eliminating the need for shaft disassembly, drilling, and dynamic balancing when retrofitting older pumps. It has strong adaptability and will not damage the bearing structure due to bearing modifications, ensuring bearing stress stability. Attached Figure Description

[0017] Figure 1 This is the main flowchart.

[0018] Figure 2 This is the flowchart for the AI ​​filter sub-process.

[0019] Figure 3 This is a flowchart of the self-healing process.

[0020] Figure 4 This is a flowchart for determining channel switching. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings.

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] A method for real-time measurement of centrifugal pump shaft temperature, such as Figure 1 As shown, Includes the following steps: Step 1: To avoid the vibration generated by the centrifugal pump from affecting the measurement accuracy of the temperature sensor, install an infrared temperature sensor on the ground or wall, independent of the centrifugal pump; install two sensor probes (A and B) with the same model, range, and optical parameters side by side on the same independent bracket, aiming at the same measurement area of ​​the bearing.

[0024] Step 2: Connect the signal lines of each infrared temperature sensor to the corresponding temperature transmitter via independent cables to form physical isolation. Then, connect the temperature transmitter to the monitoring system via wired connection as the first channel (channel A) and the second channel (channel B). The monitoring system displays and records the temperature data in real time and can perform alarm or interlock control according to the preset temperature threshold. Step 3: Form a 0.3mm thick NiCrAlY:Er³ cladding layer on the end face of the centrifugal pump shaft using a laser cladding process. + The fluorescent coating is measured using a laser-PMT component. The surface temperature T_fluoro of the shaft body is calculated based on the fluorescence lifetime. T_fluoro is used as the redundant temperature of the third channel in the temperature comparison of the monitoring system, without changing the original dual-channel physical isolation principle.

[0025] Step 4: Simultaneously attach a 5MHz ultrasonic transducer to the back of the bearing housing and measure the echo transit time Δt and sound velocity, using v(T) = 5920 – 0.8(T-20) ms. - ¹The ambient temperature T_acoustic is calculated and used as the fourth channel. This value is only used for cross-validation with the infrared channel.

[0026] Step 5: Using the fault self-diagnosis module integrated into the data acquisition unit, the integrity of the output signals of each channel is detected in real time; the integrity of the input signals is also detected in real time: open circuit, short circuit, over-range, signal freeze, etc. If the first or second channel is found to be faulty, the channel is immediately marked as "invalid" and a "sensor failure / channel fault" event is reported to the monitoring system, but no shutdown is triggered, and the valid channel continues to be monitored; if the third channel T_fluoro or the fourth channel T_acoustic is found to be faulty, it is also marked as "invalid" and reported, but it still does not participate in the original shutdown logic.

[0027] Step 6: Collect real-time pump operating data: inlet pressure P1, outlet valve position θ, flow rate Q, motor current I, and ambient temperature T_amb; like Figure 2 As shown, the desired temperature T_expected and standard deviation σ are output by the Transformer perturbation filter through a lightweight AI process; the dynamic threshold T_threshold = T_expected + 2σ + 5℃.

[0028] If cleaning or channel weight reduction is triggered, the system automatically recalculates σ to achieve "adaptive threshold". like Figure 3 As shown, the temperature difference between any two channels is calculated in real time. If the temperature difference ΔT > ΔT_threshold (3°C) and lasts for t3 (5s), a "sensor drift / failure" alarm is output. The system automatically switches to single-channel mode to continue monitoring with a higher value, but does not trigger a shutdown. In addition, a maintenance prompt pops up on the HMI to remind manual verification or replacement of the sensor. When the third and fourth channels exist, the differences |T_IR–T_fluoro|, |T_IR–T_acoustic|, and |T_fluoro–T_acoustic| between the first or second channel T_IR, the third channel T_fluoro, and the fourth channel T_acoustic will only trigger an alarm if any two sets exceed the tolerance ΔT_threshold, without stopping the machine. The original "single-channel mode" is extended to "multi-channel weighted averaging". The original PLC still only receives the final T_final, so there is no need to modify the ladder diagram.

[0029] like Figure 4 As shown, T_acoustic is used for cross-validation with the temperature T_IR measured by the infrared temperature sensor. When the temperature T_IR measured by the infrared temperature sensor exceeds the tolerance of T_acoustic for several seconds, a sensor abnormality alarm is triggered. If the difference between T_IR and T_acoustic in the first or second channel is greater than ΔT_IR_valid=2℃ and lasts for 10 seconds, a "sensor drift" soft alarm is triggered first, without triggering a shutdown, and the lens ultrasonic cleaning is started. A 15W 40kHz ultrasonic transducer is integrated inside the original infrared temperature sensor lens cover, and each cleaning lasts 5 seconds. The cleaning command is given by the edge gateway, and the cleaning feedback signal is connected to the system DI point. If the difference after cleaning is still > ΔT_IR_valid = 2℃, the weight of T_IR is reduced to 0.3, and T_acoustic is used as the main channel. The judgment logic is the same as that of the first or second channel. At the same time, the "suspicious sensor contamination" event is reported, but the shutdown is still not triggered. Temperature rise rate protection: If the temperature rise rate is > K°C / min (can be set to 5°C / min), t2 can be shortened to t2-fast (3s), balancing rapid true faults and suppression of occasional spikes. The temperature rise rate calculation prioritizes T_fluoro (true value). If T_fluoro fails, it will fall back to the original first or second channel. The rate threshold and delay parameters are still set by the user in the same configuration interface, and the original logic remains unchanged.

[0030] Step 7: If the temperature T_IR of the first or second channel infrared sensor exceeds the threshold T_threshold and remains there for t1, an audible and visual alarm will be issued. Shutdown delay t2 (10s): After the alarm is triggered, monitoring continues. If the temperature T_IR of the first or second channel is still higher than the threshold T_threshold and the temperature difference between the two effective channels is less than ΔT_threshold, then shutdown will be triggered. If the temperature difference within t2 is greater than or equal to ΔT_threshold, the sensor is considered faulty, and the shutdown command is blocked.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. The invention extends to any new features or combinations disclosed in this specification, and any modifications, equivalent substitutions, and improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention. It is obvious to those skilled in the art that the invention is not limited to the details of the above exemplary embodiments, and that detailed technical features not disclosed in this embodiment, such as specific structures, are all prior art and can be obtained by those skilled in the art from the prior art. The connection method can be a fixed connection, a detachable connection, or an integral part; it can be a fixed connection, a movable connection, or a hinged connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific manner of the above terms in the embodiments of the present invention according to the specific circumstances, and this disclosure does not specifically limit this aspect.

Claims

1. A method of real-time measurement of the temperature of the shaft of a centrifugal pump, characterized in that, The method comprises the following steps: Step 1, at least two infrared temperature sensors are installed on a support independent of the centrifugal pump; Step 2, the signal lines of the respective infrared temperature sensors are connected to corresponding temperature transmitters, and the temperature transmitters are connected to a monitoring system to obtain the temperature T_IR measured by each infrared temperature sensor as at least two infrared channels; Step 3, a fluorescent coating is formed on the end face of the shaft of the centrifugal pump by laser cladding process, the fluorescent lifetime of the fluorescent coating is measured by a laser-PMT assembly, and the shaft body surface temperature T_fluoro is calculated according to the fluorescent lifetime, which is taken as a fluorescent channel and participates in temperature comparison of the monitoring system; Step 4, an ultrasonic transducer is attached to the bearing seat of the centrifugal pump, the ultrasonic wave echo transit time Δt is measured by the ultrasonic transducer, the sound velocity v(T) is converted, and the ambient temperature T_acoustic is calculated according to the sound velocity v(T) as an ultrasonic channel for cross verification with the infrared channels; Step 5, the integrity of the output signals of each channel is detected in real time by a failure self-diagnosis module; Step 6, a dynamic temperature threshold is determined by a dynamic threshold calculation module, and the measured temperatures of the respective infrared temperature sensors are compared by a temperature comparison module; Step 7, based on the comparison results and the dynamic temperature threshold, real-time monitoring, alarm or shutdown control of the shaft temperature of the centrifugal pump is realized.

2. The method of claim 1, wherein the temperature of the shaft of the centrifugal pump is measured in real time. In step 1, the models, ranges and optical parameters of the at least two infrared temperature sensors are completely consistent, and they are installed side by side on the same independent support, and the probes of the respective infrared temperature sensors are aimed at the same measurement area of the bearing of the centrifugal pump.

3. The method of claim 1, wherein the temperature of the shaft of the centrifugal pump is measured in real time. In step 2, each infrared temperature sensor is connected to the corresponding temperature transmitter through an independent cable to form at least two physically isolated signal channels.

4. The method of real-time measurement of temperature of a centrifugal pump shaft as claimed in claim 1, wherein, In step 5, the failure self-diagnosis module detects the integrity of the input signals of each temperature signal channel in real time, and the integrity of the input signals includes signal disconnection, signal short circuit, signal out-of-range and signal freezing state; if the channel signal is judged to be failed, the invalid channel is reported, and the effective channel continues to monitor.

5. The method of real-time measurement of temperature of a centrifugal pump shaft as claimed in claim 1, wherein, In step 6, the specific calculation steps of the dynamic threshold calculation module are as follows: Step 61, collect real-time quantities of the centrifugal pump, including inlet pressure P1, outlet valve position θ, flow rate Q, motor current I and ambient temperature T_amb; Step 62, input the collected real-time quantities into a Transformer model to output the expected temperature T_expected and the standard deviation σ; Step 63, the dynamic threshold is calculated according to the formula T_threshold=T_expected+2σ+n℃; if the system triggers sensor cleaning or channel weight reduction operation, the standard deviation σ is automatically recalculated to update the dynamic temperature threshold T_threshold; Step 64, the temperature difference of any two infrared temperature sensors T_IR is calculated in real time, if the temperature difference ΔT>ΔT_threshold and lasts for t3, an abnormal sensor alarm is output, and the system automatically switches to a single channel mode to continue monitoring with a higher value or an average value, and does not trigger shutdown. Step 65: Use T_acoustic to cross-validate with T_IR of each infrared temperature sensor. When a T_IR and T_acoustic are out of tolerance and last for several seconds, trigger an abnormal alarm for that infrared temperature sensor. Step 66: Set the temperature rise rate threshold. If the measured temperature rise rate of the centrifugal pump shaft is greater than the temperature rise rate threshold, the shutdown delay will be shortened.

6. The method of real-time measurement of temperature of a centrifugal pump shaft as claimed in claim 5, wherein, In step 64, when both T_fluoro and T_acoustic exist, the differences |T_IR–T_fluoro|, |T_IR–T_acoustic|, and |T_fluoro–T_acoustic| between the infrared channel T_IR, the fluorescence channel T_fluoro, and the ultrasonic channel T_acoustic are calculated; any two sets exceeding the tolerance ΔT_threshold will only trigger an alarm without stopping the machine; the original "single-channel mode" is extended to the "multi-channel weighted average" mode.

7. The method of real-time measurement of temperature of a centrifugal pump shaft as claimed in claim 5, wherein, In step 65, if the difference between the infrared channel and T_acoustic is ΔT_IR_valid and lasts for several seconds, the sensor drift alarm is triggered first, the shutdown is not triggered, and the lens ultrasonic cleaning is started.

8. The method for real-time measurement of centrifugal pump shaft temperature as described in claim 7, characterized in that, An ultrasonic transducer is integrated inside the lens cover of the infrared temperature sensor. When the sensor malfunctions and alarms, the edge gateway sends a cleaning command to the ultrasonic transducer to control its operation. After cleaning, wait a few seconds and re-acquire the temperature measured by the infrared temperature sensor. If the difference is still greater than ΔT_IR_valid, the weight of the temperature measured by the infrared temperature sensor is reduced, and the system switches to T_acoustic as the main channel. At the same time, the system reports suspected sensor contamination to the monitoring system.

9. The method of real-time measurement of temperature of a centrifugal pump shaft as claimed in claim 5, wherein, In step 66, The temperature rise rate is calculated using T_fluoro first; if T_fluoro fails, the calculation of the temperature rise rate is reversed to the measurement temperature of the infrared temperature sensor in step 1.

10. The method of real-time measurement of temperature of a centrifugal pump shaft as claimed in claim 1, wherein, Step 7 includes: Step 71: When the infrared temperature sensor detects that the temperature exceeds the dynamic threshold T_threshold and the duration reaches t1, the monitoring system triggers an alarm. Step 72: After the alarm, if the temperature measured by the infrared temperature sensor is still higher than the dynamic threshold T_threshold, and the temperature difference between the effective signal channels of the two infrared temperature sensors is less than the preset temperature difference threshold ΔT_threshold, and the duration reaches t2, where t1 < t2, the monitoring system triggers a shutdown; if the temperature difference between the two effective signal channels is greater than or equal to ΔT_threshold within t2, it is determined that the sensor is abnormal, and the shutdown command is blocked.

Images