GB809561A - Improvements in or relating to apparatus for arc melting under reduced pressure - Google Patents

Abstract

809,561. Arc melting furnaces. HERAEUS G. m. b. H., W. C. Aug. 3, 1956 [Aug. 22, 1955], No. 24038/56. Class 39(3) Arc melting apparatus for laboratory use, e.g. for the production of samples of materials having a high melting point, comprises a vacuum vessel which supports an. electrode head above and a crucible below and is carried by and secured to an evacuation duct. As shown, a vacuum vessel consisting of a lid 1a, a cylindrical part 1b and a bottom arched ring plate 1c supports an electrode head 3 and acrucible 7, and is carried by an evacuation duct 2a which leads to a Roots vacuum pump 2. The electrode head 3 is water cooled, has handles 3a, and supports within bellows 4 on electrode 11, which may be either of the non-consumable type or of the consumable type (Fig. 2 not shown), a spring 4b serving as a centering means and as a connecting means to a raising and lowering device (not shown). Push button switches 3b, 3c, and 3d on the handles 3a control the lowering and raising of the electrode and the striking of the arc, and a regulating ring 3e controls the current regulation. The crucible 7 comprises an inner copper crucible 7a placed centrally within an outer jacket 7b having a concentric guide plate 8c for cooling water, passing through connections 8a and 8b and is screwed up in a vacuum tight manner to the part 1c. A device 17 feeds material into the appartus, and the magnetic field of a coil 18 is used to mix the melting bath contents and to stabilize the arc. Protective gases may be led to the zone of the arc by means of the pipe 9. A fork 13 suports the crucible unit when apart from the apparatus. A foot-operated lever 14 enables the unit to be pressed up against the cylindrical part 1b where it is held in position by atmospheric pressure when the vesel is exhausted.