The Pernot Furnace

THE Pernot system of rotating and withdrawing the hearth of a Siemens regenerative gas furnace for the production of Martin or open-hearth steel, is, perhaps, the most conspicuous of the several improvements which have lately been made in the steel manufacture. These several improvements in the open-hearth plant are not combined in any existing works, but most of them will be combined in not less than three works now erecting in the United States; and it seems probable that their joint result will not only reduce the cost of products of ordinary grades to Bessemer rates, but that it will produce new and better grades of products. The open-hearth steel furnace and its operation are so generally understood that but a few words of general description are necessary. The ordinary furnace is not unlike the common reverberatory puddling furnace, except that an intense, uniform, and controllable temperature is maintained by the Siemens gas regenerative system. The materials. employed are various : melted or unmelted pig with ore, and with or without scrap; pig iron purified from silicon and phosphorus, with or without scrap; pig iron and scrap, melted together in a cupola, or charged hot or cold, together or separately, into the steel furnace; a pig-iron bath, and hot or cold steel or iron scrap, direct sponge or Catalan or puddled blooms charged into the bath. The operation is, to a greater or less extent, according to the nature of the materials used, a desiliconization and decarburization of the pig or other crude iron, and its dilution by already purified materials. Manganese is employed at the end of the operation to remove oxide of iron and silica, a regulated amount of manganese remaining in the product. Figs. 2 and 3, Plate IV, represent the hearth and roof of the Pernot furnace; Fig. 1 shows, in cross section, the general arrangeent of open-hearth plant with Pernot furnaces, as generally designed by the author, and now building at two works. The engrav-