Plasma Process and Reactor for Treating Metallic Pieces

Abstract

The plasma reactor defines a reaction chamber provided with a support for the metallic pieces and an anode-cathode system, and a heating means is mounted externally to said plasma reactor. The plasma process, for a cleaning operation, includes the steps of connecting the support to the grounded anode and the cathode to a negative potential of a power source; feeding an ionizable gaseous charge into the reaction chamber and heating the latter at vaporization temperatures of piece contaminants; applying an electrical discharge to the cathode; and providing the exhaustion of the gaseous charge and contaminants. A subsequent heat treatment includes the steps of: inverting the energization polarity of the anode-cathode system; feeding a new gaseous charge to the reaction chamber and maintaining it heated; applying an electrical discharge to the cathode; and exhausting the gaseous charge from the reaction chamber.

What is claimed is: 
     
         1 . Plasma reactor for treating metallic pieces and comprising a metallic casing defining, internally, a reaction chamber provided with: a support; an anode-cathode system associated with an electric power source; an ionizable gaseous charge inlet; and a gaseous charge exhaustion outlet connected to a vacuum system, characterized in that it comprises a heating means mounted externally to the metallic casing in order to heat the latter and the interior of the reaction chamber. 
     
     
         2 . Reactor, according to  claim 1 , characterized in that the heating means transfers heat to the interior of the reaction chamber by radiation from the metallic casing. 
     
     
         3 . Reactor, according to  claim 2 , characterized in that the heating means is formed by at least one resistor in thermal contact with the metallic casing. 
     
     
         4 . Reactor, according to  claim 3 , characterized in that the support comprises multiple parallel and spaced apart ordering structures electrically coupled to the same electrode of the anode-cathode system and which are intercalated by conducting elements coupled to the other electrode of the anode-cathode system, each of said ordering structures carrying at least one metallic piece to be treated. 
     
     
         5 . Reactor, according to  claim 4 , characterized in that the direction of the heat radiation produced from the metallic casing to the interior of the reaction chamber occurs according to a direction parallel to that of the ordering structures of the support.