| 摘要 |
945,494. Furnace electrode joints. SIEMENS-PLANIAWERKE A.G. FUR KOHLEFABRIKATE. April 29, 1960 [April 30, 1959; Jan. 12, 1960], No. 15199/60. Heading H5H. [Also in Division C3] A method of coaxially joining two carbon electrodes 1, 2 by means of a cemented doubleconical nipple plug 4 in screwed engagement with respective rockets 3, 4 of the electrodes includes the steps of placing a given dosage of cement 8, 9 wrapped in a readily destroyable envelope into the socket space of the electrodes, subsequently joining the electrodes by screwing them together with the nipple plug, and finally subjecting the joint to conditions which are such as to destroy the envelope. The nipple 4 is provided with four longitudinal grooves 12, and the end faces of the electrodes have radial grooves 13, 14. The envelope may be of polyethylene foil or gelatine. The cement contains pitch, a synthetic plastic material, e.g. a resin, which thermally hardens prior to carbonization of the pitch, granular solid material, e.g. coke, graphite powder or silicides of titanium or iron, and a swelling agent, e.g. hydrazide of benzene-sulphonic acid or ammonium phosphate. The envelopes may be ruptured by screwing the electrodes tightly together and are then destroyed by thermal and/or chemical action. The carbon surfaces to be cemented are preferably pre-impregnated with a catalyzer, e.g. chloranil or phosphoric acid which attacks the envelope and promotes hardening of the cement. An insulating gasket of paper or synthetic plastic material may be provided between the end faces of the electrodes to force the current during the first few minutes of furnace operation to pass entirely through the nipple 4, thus causing a rapid heating of the cement. The gasket is at the same time carbonized and becomes conductive. |
