Patent ID: 7448151
Filing Date: 2008-11-11
Classification: B03C,B24C,E21B,Y02P

Abstract:
1. A tool for excavating an object, the tool comprising: a jetting system having a nozzle means arranged to receive a fluid and abrasive particles via an abrasive particle inlet, and arranged to impinge the object to be excavated with a jetted stream of the fluid mixed with the abrasive particles; a recirculation system arranged to recirculate at least some of the abrasive particles from a return stream, downstream of impingement of the jetted stream on the object to be excavated, back to the jetting system via the abrasive particle inlet, and a filtering means disposed in a path fluidly connecting said return stream with the abrasive particle inlet, wherein the filtering means includes an opening that is sized to keep the abrasive particle inlet free from objects of the same size or larger than the abrasive particle inlet, which filtering means allows passage of the abrasive particles; wherein the recirculation system comprises a transport device for transporting the abrasive particles in a selected direction towards the abrasive particle inlet, the abrasive particle containing a magnetic material, and the transport device comprising: