BLOW-BACK PLASMA ARC TORCH WITH SHIELD FLUID-COOLED ELECTRODE

摘要

A blow-back plasma arc torch employs a plasma gas and a separately supplied secondary fluid. The secondary fluid serves to internally cool an electrode of the torch and to shield the plasma gas and arc emanating from the primary nozzle of the torch. The secondary fluid can be a gas or liquid water. Secondary fluid or plasma gas is used to actuate a piston to which the electrode is connected so as to move the electrode from a starting position to an operating position. The secondary fluid is supplied to the torch at a greater mass flow rate than the plasma gas.