Improved Method of and Equipment for Shot-blasting and the Like

Author:  Hibbs, Brown and Gopinath
Source:  British Patent 1,084,496
Doc ID:  1967041
Year of Publication:  1967
Abstract:  
..........this invention is based on the fact that a particle of ferromagnetic material introduced into a magnetic field tends to be drawn towards the region of highest energy density. The invention makes use of the velocity acquired by the particle in being so drawn.