Apparatus for delivering air and fuel to a blast furnace

Claim 1

A BLOWPIPE FOR INSERTION BETWEEN THE TUYERE AND TUYERE STOCK OF A BLAST FURNACE COMPRISING AN INNER TUBE, OUTER TUBE SURROUNDING SAID INNER TUBE IN SPACED RELATIONSHIP THEREWITH, AN END PIECE AT EACH END OF SAID TUBES, MEANS FOR HOLDING SAID TUBES IN ASSEMBLED POSITION WITH SAID END PIECES, INSULATION IN THE SPACE BETWEEN SAID TUBES, A PLURALITY OF REFRACTORY SLEEVES FITTING SNUGLY WITHIN SAID INNER TUBE AND EXTENDING SUBSTANTIALLY THE FULL LENGTH THEREOF IN ABUTTING RELATIONSHIP, MEANS FOR PREVENTING AXIAL MOVEMENT OF SAID SLEEVES TOWARD THE TUYERE END OF SAID INNER TUBE, A THIRD TUBE FASTENED TO THE END PIECE AT THE TUYERE STOCK END OF BLOWPIPE, SAID THIRD TUBE HAVING THE SAME OUTSIDE DIAMETER AS THE INNER TUBE, SAID INNER TUBE BEING OF SUCH LENGTH AS TO PROVIDE A SPACE BETWEEN ITS TUYERE STOCK END AND SAID THIRD TUBE, A FOURTH TUBE HAVING AN INSIDE DIAMETER SLIGHTLY GREATER THAN THE OUTSIDE DIAMETER OF SAID INNER TUBE, SAID FOURTH TUBE SURROUNDING AND OVERLAPPING SAID INNER AND THIRD TUBES, AND A WELD CONNECTING THE TUYERE STOCK OF SAID INNER TUBE TO SAID FOURTH TUBE.