Ridged electrode
AssigneeThermal Dynamics Corporation
InventorsDavid J. Nelson, William Wakefield, Raymond G. Wilkins
Life of this patent
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Abstract
An electrode used in a plasma-arc torch has ridges formed on the side surface thereof for initiating a pilot arc. The required voltage for initiating a pilot arc is substantially reduced by employing this type of electrode. The ridges have much smaller radii of curvature which substantially enhance the local electric field strength responsible for creating the pilot arc discharge. The ridges are oriented substantially along the flow lines of the plasma gas so as to create the least disturbance. In one embodiment with spiral gas flow, this results in helically oriented ridges. In another embodiment with straight gas flow, the ridges are parallel to the longitudinal axis of the electrode.
Claims10
In a plasma-arc system comprising spaced, electrically conductive electrode means defining an arc chamber therebetween, pilot arc voltage supplying means connected to said electrode means, and means for supplying a flow of plasma forming gas through said arc chamber, the improvement which comprises:
- said electrode means including at least one electrode having at least one ridge formed thereon, said ridge being located substantially in said arc chamber and extending along said electrode so as to provide a path for arcing, thereby producing a longer wearing electrode.
Dependencies are inferred from the claim text.