Abstract: The invention contemplates a powder-feeding system for gas-propelled delivery of a powder to be controllably supplied, as to a flame-spraying gas torch or to a transferred-arc plasma torch. A fluidizing chamber receives (a) fluidizing-gas flow from below a porous screen, and (b) a restricted gravitational flow of powder at a relatively small central discharge location above the porous screen. A gas conduit extends transversely through the chamber between the powder-discharge location and the porous screen; it has a carrier-gas supply connection at one end and a gas-propelled powder-delivery connection at its other end. The conduit also has an upwardly extending opening virtually beneath and facing the powder-discharge location, but a shed interposed between this opening and the powder-discharge location sufficiently overlaps the opening to assure that no powder will pass through the opening and into the conduit unless it has been gas-fluidized.

Abstract: The invention contemplates a plasma-transferred-arc torch construction wherein, optionally, a single releasable clamp enables rapid separation of downstream-end fittings of an anode subassembly and a cathode subassembly, as for inspection, servicing and/or replacement; in an alternative option, release of the single clamp enables rapid further disassembly of the entirety of the respective subassemblies from mounting structure which includes the single clamp. These options are available for torch structure incorporating provision for sealed independent fluid-flow supplies of (a) coolant serving both electrode subassemblies, (b) plasma gas serving an annular interelectrode gap at the downstream end of the torch, (c) a metallic, ceramic or other powder fluidized in a carrier gas, for torch-deposition of the powder, and (d) a shielding gas to protect the zone of plasma-transfer of the arc and any powder conveyed therewith.

Abstract: The invention contemplates a powder-feeding system for gas-propelled delivery of a powder to be controllably supplied, as to a flame-spraying gas torch or to a transferred-arc plasma torch. A fluidizing chamber receives (a) fluidizing-gas flow from below a porous screen, and (b) a restricted gravitational flow of powder at a relatively small central discharge location above the porous screen. A gas conduit extends transversely through the chamber between the powder-discharge location and the porous screen; it has a carrier-gas supply connection at one end and a gas-propelled powder-delivery connection at its other end. The conduit also has an upwardly extending opening virtually beneath and facing the powder-discharge location, but a shed interposed between this opening and the powder-discharge location sufficiently overlaps the opening to assure that no powder will pass through the opening and into the conduit unless it has been gas-fluidized.

Abstract: The invention contemplates an elongate extension nozzle attachment for a gas torch whereby flame-spraying of coating-powder material may be applied with precision to the bore of a workpiece. The attachment is detachably securable to conventional torch and/or gas-distributor structure and provides independent flows of (a) carrier gas and powder and (b) combustible-gas mixture to a nozzle which is removably fitted to the discharge end. Provision is made for optional use of one or more flame-shaping discharges of air, inert gas or the like at the discharge end, using a further independent supply system within the attachment.