Rubber
| Tue 16 Jun 2026
Beijing, June 16 -- State Intellectual Property Office of China has received Rongsheng Machinery Mft Ltd Of Huabei Oilfield patent application for Multi-petal Combined Rubber Core for Annular Blowout Preventer. Zhang Jian, Sun Xun, Meng Qingrong, Hao Xiaoyong, Wang Hongjie, Wu Liangliang, Qu Zhiming, Xu Hongqi, Li Haohao, Meng Z..