The Perkin-elmer Corporation

Metco, Inc.

Richard A Goehring

Mark Frank Spaulding

A system for feeding powder into high backpressure includes a carrier gas conduit with an orifice for entraining powder from a hopper, and a line for discharging feed gas at regulated pressure into the hopper to effect entrainment. A gas bleeder line has an outlet connection to the output carrier conduit, with a line pressure representative of carrier pressure. A differential pressure regulator equal to carrier pressure plus an increment. A regulated relief valve in the input carrier gas conduit provides a bleed gas supply to the bleeder line at a pressure equal to carrier pressure plus an increment. Pinch valves in the carrier conduit allow or prevent powder entrainment; alternatively, a rotatable sleeve is on the carrier conduit with a side opening alignable with the entrainment orifice. A carrier bypass conduit may be connected between the input conduit and the output conduit and hopper pressurization line may be connected between the output conduit and the hopper. An optional exhaust system may replace the bypass and pressurization lines and includes a differential exhaust valve to exahaust gas from the hopper when hopper pressure exceeds feed gas pressure.

High pressure power feed system

A thermal spray gun includes a first burner for producing a first fan-shaped flame, a second burner for producing a second fan-shaped flame parallel to the first in sufficient proximity to commingle into a combined fan-shaped flame. Powder is dispersed into a fan-shaped powder spray entrained between the first and second flames. The gun body has a fan-shaped powder chamber with an open side opening forwardly from the gun body between the first flame and the second flame and with an apex location opposite the open side. First and second powder ducts each terminate at the apex location with a common axis perpendicular to the fan-shaped chamber such as to mutually impinge the first and second powder streams into a combined powder stream dispersing through the fan-shaped powder chamber into the fan-shaped powder spray. A first fan-shaped air flow is introduced between the first flame and the fan-shaped air flow is introduced between the first flame and the fan-shaped powder spray, and a second fan-shaped air flow is introduced between the second flame and the fan-shaped powder spray.

Thermal spray gun with fan spray

A powder feeding system for a thermal spray gun provides uniform control of powder feed rate with a minimum of pulsation during operation and without feeding during idle mode. The feeder is comprised of an enclosed hopper for containing a powder to be thermal sprayed, a carrier conduit connected between a carrier gas supply and a thermal spray gun, a feed gas conduit for discharging a regulated supply of feed gas under pressure into the hopper, and one or preferably more powder intake orifices extending from the carrier conduit into the hopper below the normal minimum level of powder. The intake conduits have a geometric design and arrangement such that there is no gravity flow of powder therethrough into a carrier gas stream in the absence of a feed gas flow therethrough. The axes of the intake orifices extend away from the carrier conduit at an acute angle to the axis of the carrier conduit as defined by the direction of carrier gas flow. Preferably there is a constriction in the carrier conduit downstream of the intake orifices.

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Huntington Station, NY, United States of America

Richard A Goehring