Patent ID: 7935909

Claim:
A method of controlling the flow of gases through a plasma arc torch having an electrode adapted for electrical connection to a cathodic side of a power supply and a tip positioned distally from the electrode to define a plasma chamber therebetween, the method comprising: directing a flow of plasma gas to the plasma chamber; directing a first flow of auxiliary gas around a plasma stream that exits the tip in one of a swirling manner and a radial manner; and directing a second flow of auxiliary gas around the first flow of auxiliary gas and the plasma stream in one of a coaxial manner, an angled manner, and a radial manner, wherein the first and second flow of auxiliary gases are directed through auxiliary gas chambers formed in a shield device that comprises an inner shield member and an outer shield member surrounding the inner shield member, the first flow of auxiliary gas functions to constrict and shape the plasma stream to improve cut quality and cut speed, the first flow of auxiliary gas being directed inwardly from the inner shield member, and the second flow of auxiliary gas functions to protect the plasma arc torch during piercing and cutting and to cool components of the plasma arc torch such that thicker workpieces may be processed with a highly shaped plasma stream, the second flow of auxiliary gas being directed axially through the inner shield member and into an auxiliary chamber between the inner shield member and the outer shield member.