GB1317918A - High temperature apparatus - Google Patents

Abstract

1317918 Arc heating apparatus HUMPHREYS CORP 30 Oct 1970 [14 Nov 1969 (2)] 51686/70 Heading H5H Apparatus for heat treating materials to effect chemical or physical changes or for use as a light source, heat source or for use in flame spraying comprises a chamber 10 containing a plurality of rod anodes 52 arranged in a common plane with their arcing ends adjacent and angularly spaced about a central axis and a cathode rod 92 arranged to lie on the central axis with its end spaced from the said common plane so that when a suitable supply 208 is applied between the anodes 52 and cathode 92 a cathode jet 210 and an elongated high anthalpy tail flame 212 extend from the anodes into the tapered section 22 of the chamber. The cathode (Fig. 3) 92 comprises a tapered tungsten tip 98 secured to watercooled copper sections 96, 94. A nylon sleeve 90 around cathode 92 is surrounded by a cylinder 82 which cooperates with a ring 80 to define an annular channel 84 provided with a series of ports 86 in its inner wall to introduce a shielding gas e.g., argon, to a nozzle 72 surrounding tungsten tip 98. The nozzle 72 is seated in a plate 60 provided with three angularly spaced material feed passages 64 which may be supplied with a carrier gas to convey particulate material to the arc zone cathode tip and the anodes. A water cooling channel 76 fed from passage 78 is provided in plate 60. Each anode 52 (Figs. 4 and 5) is supported by rollers 122, 124 of a drive assembly 54 and by a bushing 120 in a power supply assembly 56. A base structure 170 has three shafts 172, 174, 176, which carry a toothed roller 206 and the rollers 122, 124 respectively. Sprockets 194, 196, 198 on respective shafts 172, 174, 176 are linked by a chain 200 tensioned by a spring biased idler sprocket 202. The axis of roller 206 is skewed so when shaft 172 is rotated by motor 190 through reduction gear 188 via worm gear 182 and worm 184, the anode rod 52 is slowly advanced whilst being continuously rotated. The power supply assembly 56 comprises a graphite probe 140 spring biased against anode rod 52. The anodes and cathode may both be made of graphite in which case the cathode has a drive and power supply assembly similar to the above. Particles introduced to the arc region and passed through the elongated high enthalpy zone by carrier gas can be spheroidized by free fall or flattened on impact with a surface.