Electric resistance furnaces

Claim 1

AN ELECTRIC RESISTANCE FURNACE OF THE KIND INTENDED FOR INDUSTRIAL PURPOSES, SAID FURNACE HAVING AN INSULATED FURNACE ROOM AND BEING EQUIPPED WITH RESISTANCE ELEMENTS WHICH CONSIST OF MOLYBDENUM DISILICIDE, MOSI2'', SAID ELEMENTS BEING OF HAIRPIN SHAPE AND EACH AHVING A GLOW PORTION DEPENDING FREEL INTO SAID FURNACE ROOM, EACH RESISTANCE ELEMENT HAVING TWO SLIGHTLY SPACED ELECTRODES PROVIDED WITH LEAD-IN PARTS EXTENDING THROUGH THE FURNACE INSULATION, THE INSULATION HAVING A CENTRAL PART THROUGH WHCIH THE LEAD-IN PARTS OF THE ELECTRODES EXTEND, SAID CENTRAL PART CONSISTING OF A TUBE-SHAPED SLEEVE PREFERABLY COMPOSED OF A CERAMIC MATERIAL, SAID SLEEVE SURROUNDING AND SPACED FROM THE PARTS OF THE ELECTRODES WHICH PASS THROUGH IT, INSULATING PLUGS LOCATED RESPECTIVELY IN THE UPPERMOST AND LOWERMOST ENDS OF THE TUBE AND THROUGH WHICH PARTS OF THE ELECTRODES EXTEND TO FIXEDLY SECURE THE ELECTRODES, SAID TUBULAR CENTRAL INSULATION PART TRANSMITTING HEAT DEVELOPED IN THE LEAD-IN PARTS OF THE ELECTRODES TO A CENTRAL LAYER OF THE FURNACE INSULATION LOCATED AROUND THE FIRST-MENTIONED CENTRAL PART OF THE INSULATION, THE LAYER BEING PROVIDED NEAR THE LEAD-IN ENDS OF THE ELECTRODES WITH AT LEAST ONE COOLING CHANNEL, SAID CHANNEL EXTENDING PERPENDICULARLY TO THE DIRECTION IN WHICH THE LEAD-IN ENDS PASS THROUGH THE FURNACE INSULATION, SAID COOLING CHANNEL BEING OF A LENGTH TO COOL THE LEAD-IN ENDS OF A PLURALITY OF THE RESISTANCE ELEMENTS ARRANGED IN A ROW, THE INSULATION OF THE FURNACE ROOM INCLUDING LAYERS LOCATED ABOVE AND BELOW THE CENTRAL LAYER, SAID UPPER AND LOWER LAYERS BEING COMPOSED OF AN ELECTRICALLY INSULATING MATERIAL OF LOW CONDUCTIVITY.