A large number of industrial application results show that the particle size of a large circulating cyclone (diameter greater than 1.2m) can reach about 1.2 micron, and the pressure drop is only 500 ~ 1 000 Pa. After the diameter increases, the separation efficiency will not decrease obviously, and it has the advantages of strong operational stability and flexibility. This series of patent achievements passed the project appraisal organized by the Science and Technology Department of Shandong Province and presided over by Yu Guocong, academician of China Academy of Sciences, Li Hongzhong and Jin Yong, academicians of Academy of Engineering, respectively in February and October, 2004. Their appraisal opinion is that it has reached the international leading level of similar technology and equipment. In 2005, he won the second prize of Shandong Technological Invention, and 20 1 1 won the first prize of Shandong Technological Invention.