GB843975A - Improvements in and relating to casting in vacuum and inert gas - Google Patents

Abstract

843,975. Casting-machines. METROPOLITAN-VICKERS ELECTRICAL CO. Ltd. April 7, 1959 [Jan. 7, 1958], No. 632/58. Class 83 (1). [Also in Group XII] A casting-apparatus comprises a movable structure containing a vacuum or inert gas chamber enclosing a furnace, a mould enclosure in connection with said chamber through a valve, means for raising and lowering said enclosure and for discharging the furnace, and casting molten metal therefrom through said valve into a mould in said enclosure. The vacuum-chamber assembly 20, vacuum pumps 79, 80, 90 and ancillary equipment, are mounted on a turntable 6 rotatable about a vertical shaft 2 by a motor 10, and vertically movable by a pair of lead-screws driven by a motor 18, so that the mould-enclosure 33, forming an integral part of the chamber 20, may be moved to surround in turn each of a number of moulds 40 on stands 39 placed equidistantly about the rotational axis of the turntable. The supports 39 may comprise a turntable 41, rotated for centrifugal casting, or a vibratable plate. The vacuum chamber encloses an induction furnace 24, tiltable in two stages 241, 24<SP>11</SP> about trunnions 25, 26 respectively, by a motor-driven winch 31. The cast is directed through the valved outlet 43 to the mould 40 by a tundish 42, which is tiltable and movable axially by an external handle 52. The furnace may be charged through a chamber 56 with bar-stock supported on a hook 62 operated by a hand winch 60. The chamber cover 58 containing the feed means may be replaced by other covers containing a pyrometer or a rod for breaking up slag &c. on the melt-surface in the furnace. A second charging-chamber supports a pivotallymounted elongated bucket 67 operable by a hand wheel 71 through a universally-jointed shaft 70, to tip small pieces of metal, fed to the bucket through a shoot 67a, into the furnace. The charging chambers, chamber 46, and mouldenclosure 33 are all capable of being sealed-off from the vacuum chamber, and individually evacuated. An inspection window chamber 53 may also be sealed-off from the chamber 20, so that the window may be removed for cleaning. The mould enclosure supports, at its lower end, a sealing arrangement comprising sealing-rings 36, 36a, and rings 35, 35a slidable on the enclosure wall 33 and having between them alternately, springs 37 and locating-pins. The ring 35a is linked to an air-cylinder 38d so that operation of said cylinder compresses, through the springs 37, the sealing-rings 36, 37a to form an initial seal, final loading being applied when the enclosure is evacuated. Instead of being mounted on a turntable, the vacuum-chamber &c. may be mounted on rails or on a gantry so that it may serve a line of moulds, or the platform may be arranged as a truck.