Patent ID: 6207923
Filing Date: 2001-03-27
Classification: H05H

Abstract:
A plasma arc torch for marking or cutting a metallic workpiece, the plasma arc torch comprising:a torch body including a plasma flow path for directing a plasma gas to a plasma chamber in which a plasma arc is formed;a nozzle mounted relative to an electrode in the torch body to define the plasma chamber, the nozzle comprising a hollow nozzle body portion and a substantially solid nozzle head portion formed integrally with the nozzle body portion and defining a nozzle orifice extending therethrough; anda shield which includes (1) a shield body portion with a fastening mechanism for securing the shield to the torch body in a spaced relationship relative to the nozzle such that a shield gas passes through a space between the shield body and the nozzle body portion and (2) a shield head portion formed integrally with the shield body portion and defining a shield exit orifice having an inlet and an outlet, the shield exit orifice dimensioned such that the nozzle head portion extends to a position between the inlet and the outlet of the shield exit orifice (a) to provide a substantially columnar flow of the shield gas that passes through a gap between the shield head portion and the nozzle head portion, the substantially columnar flow surrounding the plasma arc without substantially interfering with the plasma arc, and (b) such that the nozzle head portion is recessed within the shield head portion relative to said outlet of said shield exit orifice to prevent a substantial portion of splattered molten metal produced during marking or cutting of the workpiece from reaching the nozzle.