GB1424578A - Arc heating apparatus - Google Patents

Abstract

1424578 Degassing molten metal STANDARD-MESSO DUISBURG GES FUR CHEMIETECHNIK mbH & CO 18 April 1973 [25 Jan 1973] 18615/73 Heading C7D [Also in Divisions H3-H5] An electric arc vacuum heating apparatus has segmented graphite electrodes 4 each supported . by a lifting device 6 and extending into a container 1 through a pair of sleeves 7a, 7b that provide a vacuum lock enabling further sections 13 to be added to the electrode without breaking the vacuum in the container. Each electrode 4 is composed of section 12 and extends into container 1 though holes 10 in lid 2 and radiation shield 2a. Sleeve 7a is vacuum tightly attached to the lid around hole 10 and a vacuum tight sealing means is provided between this sleeve and the electrode that permits raising and lowering of the electrode. Second sleeve 7b surrounds first sleeve 7a and is sealed to it by stuffing box 7c. Sleeve 7b also surrounds the upper part of electrode 4 and is provided with a vacuum tightly closable lid 9 through which additional sections e.g. 13 are added to electrode 4. The electrode is gripped between spring-loaded jaws 6a operable hydraulically, connected to lifting device 6 by a current supply arm 5 that passes vacuum tightly through sleeve 7b. In use, when it is desired to add an electrode section, current is supplied through a second electrode 4 to keep the process going. The first electrode is then lifted to its highest point, vacuum in the lock is broken, lid 9 opened, a new section 13 attached, jaws 6a released, the electrode lowered to its new position, jaws 6a closed, lid 9 closed and the lock again evacuated. Compensator 8 permits some tilting of sleeve 7b during addition of the new electrode section. The metal to be melted or degassed may, but need not, be in a separate vessel 3.