| 摘要 |
661,696. Gems. GENERAL ELECTRIC CO., Ltd., and BROWN, K. W. March 21, 1950 [March 23, 1949], No. 7954/49. Class 43. Apparatus for making a synthetic crystal boule or rod of varying composition with substantially no interruption of the crystallization includes a plurality of reservoirs for different constituent materials and means for periodically varying the reservoir from which material is fed into a furnace chamber where it is fused and progressively crystallized on a surface. A powder dispenser 4 houses two powder containers 5, 6, each filled with alumina powder containing a different colouring agent from the other, so that by selective operation of hammer mechanisms 7, 8, a quantity of one or other of the powders may be shaken through a sieve 19 at the bottom of its container to be carried, by a flow of oxygen entering via a union 15, through a funnel 18 of the dispenser and an oxyhydrogen burner 2 to a furnace chamber 3. Hydrogen enters via a union 14 and passes through six passages equally spaced round the burner, while the oxygen passes through a central passage thereof. The molten material progressively crystallizes into a corundum rod on the top of a ceramic rod 10 supported by a metal rod 11, which is vertically adjusted by means of a rack 12 and a pinion 13 driven by an electric motor. Preferably movement of the rod 10 is automatically controlled according to the rate of growth of the corundum rod as described in Specification 633,118. The length of any coloured section may be automatically fixed by mechanism controlling the period of feed from a container, e.g. an electric timing circuit may energise the hammeroperating motors successively for predetermined periods. Material may be fed from more than one container at a time if desired. Crystals of more than two colours may be produced by using more powder containers and hammers, or by mounting several containers in a rotatable turret in the dispenser 4 such that any one of them may be brought beneath a single hammer. Alternatively the dispenser 4 may be in two (or more) parts, each housing a removable powder container, so that one container may be changed while the other is in use; in this embodiment the oxygen supply may be switched by means of valves to flow only through the container in use, escape of oxygen during change of container being thus prevented. |
