Fellas:
I've been reading too much iron and steel. Sorry for the confusion. My mistake by mixing and matching forge, furnace and hearth. Maybe there should be some definitons of the primary types. But below is info concerning hearths and heated air.
All below is from Bell’s(1884) “Manufacture of Iron and Steel”
“The hearth and Catalan fire-as the latter was called from its use in that province-blown by means of a fall of water known as the trombe, or by bellows, were the only means employed for ages in furnishing the world with the iron it required.”
“Some Catalan furnaces, which I had an opportunity of examining in North Carolina, were near 3 feet from back to front and 2 feet from side to side, by 18 inches or 2 feet in depth. They were blown by a trombe-a very simple form of apparatus, in which the current of air is produced by water falling through a square upright box of wood, the blast being conveyed to the hearth through stems of trees bored for the purpose. Into the furnace are thrown charcoal and ore, the latter in small fragments. The hot embers, and the masonry heated by the previous charge, quickly cause combustion to pervade the mass, when the blast is turned on.”
“Contemporaneously with the use of the Catalan hearth, at all events in later times, the Stuckofen was worked in Germany, and the Osmund furnace was employed in Sweden, both being driven with compressed air. A mere addition to the height constituted all the essential difference between these two forms of furnaces and their primitive predecessor.”
Niklas has stated that the Osmund was a type of pig iron.
“The writings of these two authors, Agricola(Georg Bauer) and Dudley(Dud), appear, therefore, to fix the date of its(blast furnace) introduction at somewhere about the beginning of the sixteenth century.”
In Sweden and Russia until the latter part of the 18th century, a hearth similar to the Catalan know as the Lancashire hearth was used.
“The march of improvement seems to have been but languid, for, with the aid of the steam engine and the substitution of iron cylinders for leathern bellows, the average weekly make in 1788 of the 85 furnaces in the kingdom was scarcely 15 ½ tons per furnace.”
“So far as I know, neither Bessemer(Sir Henry) nor Siemens and Martin ever had a word to say against the hot blast. But a more striking instance even that this is that afforded by Sweden. In the manufacture of that quality of Swedish iron which has a world-wide reputation for cutlery steel, no new process is rashly introduced; and the Swedish ironmasters, no doubt for good reasons, adhere to the use of the old Lancashire fire, and, for the highest qualities, have forbidden the introduction of the puddling furnace into their primitive forges.
No iron making community in the world is more dependent for mere existence on a continuance of ancient reputation than the Swedes. They saw nothing in the adoption of the hot blast to impair their traditional renown; and I believe at the present moment that the use of hot air is the rule in their country.”
“since the ore employed for their manufacture is almost free from sulphur and phosphorus, and charcoal, the fuel used in Sweden and Russia for the blast furnace and Lancashire and Walloon fires, is the purest form of solid combustible with which we are acquainted.”
Kind Regards,
Raimey
rse
Last edited by ellenbr; 01/09/08 11:29 PM.
