Research on Pump Inspection Cycle Early Warning Method Based on Big Data Du Lihong, Liu Yufang, Cao Fei, Li Fang, Min Guizhi, Liu Zhongbo, Xia Zhixue and Zhang Zhanmin E3S Web Conf., 245 (2021) 02026 Published online: 24 March 2021 DOI: 10.1051/e3sconf/202124502026