Automatic plasma flame spraying process and apparatus

摘要

A plasma flame-spraying apparatus, having a source of primary gas and a source of a secondary plasma gas, is provided with means for insuring that when the secondary gas in passed through the electric arc established in the flame-spraying apparatus, which secondary gas flow causes an increase in the voltage in the current of the circuit containing the arc, the current is suitably adjusted. The apparatus includes means for insuring that the ignition of the arc is established by pressing a single switch. There is also provided a closed loop system of determining the voltage changes in the arc circuit and for compensatingly regulating the current at a fixed plasma gas flow-through rate and composition to maintain a desired balance between current and secondary gas flow. Various automatic means are provided for insuring against excessive constriction of the confined electric arc within the nozzle of the apparatus or parts associated therewith.