Patent GB-697419-A (GB)
Title: Improvements in or relating to apparatus for manufacturing synthetic jewels
IPC: C30B11/10
Filed: 1951-07-13
Abstract: 697,419. Gems. GENERAL ELECTRIC CO., Ltd., DAUNCEY, L. A., and TIMMS, D. G. June 27, 1952 [July 13, 1951; June 6, 1952], Nos. 16697/51 and 14343/52. Class 43. [Also in Group XXIV] Apparatus for manufacturing synthetic gems by passing a stream of gas carrying the con stituent of the gems ir powder form to a furn ace chamber wherein crystallisation of the molten constituent is effected, is adapted for manufacturing simul. taneously two or more gems by feeding the stream of gas and powder from a central duct 10, Fig. 2, into a distributor provided witl secondary ducts 17 leading to a furnace chamber 3 associated with a supporting member 23 upon which gems equal in number to the num. ber of ducts are built up progressively in the form of vertical rods means being provided for effecting relative vertical movement be tween the supporting member and the open ings of the secondary ducts into the furnace chamber in order to maintain a substantially constant distance between the tips of the rods and the said openings. The relative vertical movement may be effected and controlled by a photo-electric cell 42 and apparatus such as that described in Specification 633,118. In the example a stream of oxygen and alumina powder passes down a primary duct 10, Fig. 2, and then upwardly through an annular passage formed by a cylindrical member 14 which also provides an annular downward passage 13 between its outer surface and the inner surface of a tubular housing 9, the stream of oxygen and alumina powder being thus fed to six secondary ducts 16 arranged symmetrically within a member 15. The ducts 16 each lead into a tube 17 communicating with a vertical orifice in a member 18 mounted in the top plate 4 of the furnace chamber 3 to which hydrogen is fed by way of a pipe 19 and a toroidal cavity in the top plate and producing six flames 21. The fused alumina powder is built up by progressive crystallisation into vertically extending rods 22 of synthetic corundum upon six ceramic rods 24 which are mounted on the supporting member 23 and extend through an aperture in the base plate 5 of the furnace chamber. The supporting member 23 is mounted upon a tubular member 25 associated with an indexing mechanism within a casing 26 and arranged to rotate the supporting member 23 through an angle of 60 degrees once every half minute, bringing each of the rods 24 accurately beneath an opening from a secondary duct 16 into the furnace chamber. The indexing mechanism comprises a vertically movable plunger rod 33, Fig. 4, mounted in a head 32 carried at the end of a hollow piston rod 31 with an axial passage through which compressed air is fed to the head of rod 33, the piston rod 31, with piston 30, being also mounted for movement within a fixed cylinder 29 when compressed air is fed to the latter. The upper end of the flanged rod 33 is thus arranged to be brought successively into engagement with with each of six spokes 28, Fig. 3 (not shown, see Group XXIV), extending radially outward from a collar 27 secured on the lower end of the tubular member 25, and the outward movement of the piston rod 31 relative to its cylinder 29 causes the rotation of the member 25.