Abstract: To protect the collimator of a transferred plasma arc torch from premature failure due to corrosion, an anti-corrosive covering is applied on the exposed face surface and a portion of the inner exit bore of the collimator. The specification describes several methods for producing the collimator for a plasma torch having an anti-corrosive coating or cladding on the exposed surfaces thereof, including electroplating, electroless plating, flame spraying, plasma spraying, plasma transferred arc, hot isostatic pressing and explosive cladding.

Abstract: A plasma arc torch is provided which is convertible in the field as to be able to operate in either a transfer arc mode or non-transfer arc mode. The plasma arc torch comprises a torch body having channels formed for flow of coolant and plasma gas therein. The torch body further comprises an anode and a cathode base and terminates at a threaded connection point. Adapted to be assembled to the threaded connection by means of mating threads is, alternatively, either an end cap or a cathode extension assembly, thereby establishing a plasma arc torch capable of operating in either a transfer arc mode or a non-transfer arc mode. When the end cap is connected, the cathode base is not energized. The cathode extension assembly contains a cathode extension which connects to the cathode base on assembly. Both the cathode base and cathode extension are energized to form the active cathode for the non-transfer arc mode operation.

Abstract: A plasma arc torch is provided which is convertible in the field as to be able to operate in either a transfer arc mode or non-transfer arc mode. The plasma arc torch comprises a torch body having channels formed for flow of coolant and plasma gas therein. The torch body further comprises an anode and a cathode base and terminates at a threaded connection point. Adapted to be assembled to the threaded connection by means of mating threads is, alternatively, either an end cap or a cathode extension assembly, thereby establishing a plasma arc torch capable of operating in either a transfer arc mode or a non-transfer arc mode. When the end cap is connected, the cathode base is not energized. The cathode extension assembly contains a cathode extension which connects to the cathode base on assembly. Both the cathode base and cathode extension are energized to form the active cathode for the non-transfer arc mode operation.