IMPROVEMENTS IN FURNACES FOR THE MELTING AND REDUCTION OF STEEL, COPPER, ZINC, AND OTHER METALS,
Year: 1858

page_text: application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
of the Commissioners of Patents, with his Petition, on the 28th April
1858. A communication from Charles André, Mechanician.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North
Britain, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN FURNACES FOR THE MELTING AND REDUCTION OF STEEL, COPPER,
ZINC, AND OTHER METALS," a communication from Charles André, Mechanician,
a foreigner resident abroad, to be as follows:-
This Invention relates to certain peculiar constructions and arrangements of
furnaces for melting and reducing steel, copper, zinc, and other ores, whereby
a considerable economy of fuel is effected, and the minute metallic particles
and flakes of metal, so injurious to the workmen, are carried off.
The present improvements consist in the introduction of heated air and its
admixture with the flame by means of passages or tubes, built or set in
masonry, which act as blow pipes upon the flame as it enters the melting
furnaces. The melting or reducing furnaces are disposed round a main
central furnace which heats the series. This central furnace is fed with fuel
from above, and is supplied with a hot blast, and which inclines or spreads the

page_text: flame on two or three of its sides into a corresponding number of melting
furnaces containing the retorts or crucibles filled with the ores or metals,
according to the nature of the operation to be performed. Above the furnace
is fitted a hood or bell-mouthed receptacle, which is open at the lower side, and
is provided with blast pipes round its lower lip, the upper end of the hood
communicating by pipes for that purpose with the main chimney. An active
current or draught is kept up in the chimney by means of a powerful steam
jet or jets proceeding from a perforated mouthpiece on a boiler for that
purpose, which is heated by the waste heat of the furnace.
The combination of the air blasts in the hood, and the draught in the
chimney, creates a powerful upward current of air, which effectually carries off
the smoke and metallic particles of any kind, and especially those from zinc
furnaces, the flakes from that metal being conducted by the chimney into a
serpentinal condensing chamber. The air is heated for supplying the furnaces
by passing through suitable coils of pipes acted upon by the waste heat of the
furnace.
These several improvements are applicable to all furnaces employed in the
reduction and melting of ores and metals. In steel melting furnaces the heat
and flame on leaving the central or main heating furnace enters the melting
furnaces containing the crucibles, thence it passes to chambers containing the
air pipes for the hot blast, and passes thence into other chambers, for the
purpose of heating the crucibles therein, which crucibles are afterwards
removed to the melting furnaces, whence the gases and products of combustion
enter the chimney, which is common to all the heated gases.