Study on the Influence of Pump Performance Curve Fitting and Seal Ring Wear on Pump Intelligent Monitoring

With increasing demands for energy efficiency and environmental sustainability in pump stations, the development of digital and intelligent pump systems has become crucial. In this study, we focus on three speed ratios of pumps and propose a classification algorithm for pump performance curve fitting using the polyfit function based on the least squares principle. Software programs were developed to model and analyze pump performance curves. Additionally, the impact of seal ring clearance on pump performance and energy consumption was analyzed for pumps with specific speeds of 96.2, 185.5, and 493.3. External characteristic tests were conducted to evaluate these effects. When the clearance value of the sealing ring increases, the head and efficiency of the submersible sewage pump gradually decrease, while the shaft power of the pump presents different variation trends with an increase in the specific speed of the pump. When the specific speed is low–medium, the shaft power of the pump gradually increases. However, when the specific speed is relatively high (ns > 300), the shaft power initially decreases, then increases, and finally decreases again. For intelligent monitoring, key variables and auxiliary power parameters were identified and mathematical models (Q-P and Q-H) were established as the basis for a soft measurement system. The results show that the Q-H, Q-P, and Q-η curves are generally fitted with polynomial curves of the third~fourth order. The maximum polynomial degree without inflection points is 3, while the maximum number of inflection points is 4, the two inflection points are fitted by segmentation. The pump monitoring system can integrates with an industrial cloud platform, enabling real-time parameter display, control, alarm of functions, recording and analyzing the historical data and operation trends. This research is significant for safe operation monitoring and energy conservation in pump systems.