As regards the first of these advantages, it may be stated that the
puddling of ordinary Ougrée forge iron, which required with other
furnaces 900 to 1,000 kilogrammes of coal, is now performed with less
than 600 kilogrammes per ton of the iron produced. The puddling of fine
grained iron which required 1,300 to 1,500 kilogrammes of coal is now
done with 800. So much for quantity; as for quality the system presents
also a very marked advantage in that it requires no rolling coal--the
operation of the furnace being just as regular with fine coal, even that
sifted through screens of 0.02 meter.
The second class of advantages naturally results from the almost
complete prevention of access of cold air. The saving in wastage amounts
to 3 or 4 per cent., that is to say, 100 kilogrammes of iron produced is
accompanied by a loss of only 9 to 10 kilogrammes, instead of 13 to 15
as ordinarily reckoned.
The diminution in the cost of repairs is due to the fact that the
furnace doors, of which there are two, permit of easy access to all
parts of the sole; moreover, the coal never coming in contact with the
fire-bridges, the latter last much longer than those in other styles of
furnaces, and can be used for several weeks without the necessity of
the least repair. The reduced wear of the grates results from the low
temperature that can be used in the furnace, and the quantity of clinker
that can be left therein without interfering with its operation, thus
permitting of having the grates always black. These latter in no wise
change, and after five months of work the square bars still preserve
their sharpness of edges.
As for the improvements in the conditions of the work of puddling, it
may be stated that with a uniform price per 100 kilogrammes for all the
furnaces, the laborers working at the gas furnaces can earn 25 to 30 per
cent. more than those working at ordinary furnaces.
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