Arc spray system

Claim 1

In an arc spray system for melting the ends of two electrically isolated metal wires in an electric arc struck between the wire ends and spraying the resulting molten metal, an arc spray gun (10) which comprises a head member (11) having a generally frusto-conical configuration with a small end facing forward, a pair of electrically isolated tubular wire guides (22,22′) extending through the head member (11) and converging towards the small end thereof so as to insure proper contact of the wire ends for arc formation, a gas jet nozzle (26) adapted for connection to a primary source of compressed gas and positioned with respect to the ends of the tubular wire guides (22, 22′) to provide uniform atomization of the molten metal, means (47,48) for connecting the metal wires to a source of arc current, and means (14) for feeding the metal wires respectively through each tubular wire guides (22,22′); a gas cap (28) of cup-shaped configuration with a forwardly facing surface having an opening (43) therein, disposed in a coaxial position on the head member (11), the gas cap (28) having at least one orifice (37, 37′) therein for directing gas so as to modify the molten metal spray, characterized in that the gas cap cooperates with the head member (11) to define a gas chamber (32,32′) therebetween, with rear and forward gas seals (29,30) interposed between the head member (11) and the gas cap (28) at locations, respectively, rearward and forward of the gas chamber, the head member (11) having a gas duct (36,36′) therein adapted for connection to a secondary source of compressed gas and communicating with the gas chamber (32) for directing the secondary gas so as to modify the molten metal spray, and that the gas cap (28) has two diametrically opposite orifice systems (82, 82′; 83, 83′) therein connected with the gas chamber (32), and that each orifice system has an elongated cross section with a long dimension (L) tangential to a circle coaxial with the symmetry axis of the metal spray.