Sanitation
| Sat 18 Jul 2026
Beijing, July 18 -- CNPC Greatwall Drilling and China National Petroleum have sought patent for Automatic Rock Debris Cleaning Device. This invention was developed by Zhang Wucai, Xu Hairen, Meng Xiangwen, Cong Fengxiao, Xu Guitian, Zheng Lijun, Chen Zhiwei, Song Minghui, Sun Haigang, Zhang Shuo, Wang Yang, Yan Yangyang, Li Xian..