IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL, AND IN FURNACES TO BE USED IN SUCH MANUFACTURE
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Joseph Henderson at the Office
of the Commissioners of Patents, with his Petition, on the 8th
January 1869.
I, JOSEPH HENDERSON, of Auchencairn, near Castle Douglas, North
Britain, Gentleman, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL, AND IN
FURNACES TO BE USED IN SUCH MANUFACTURE," to be as follows:-
This Invention relates to a novel construction of puddling furnace
which will enable me to manufacture iron and steel with considerable
economy, and carry on conveniently the processes of puddling and steel
melting in crucibles (for the manufacture of best tool steel) at one and
the same time.
The furnace may be termed a double reverberatory furnace, as the
hearths, four in number, are arranged two in a line and placed back to
hack to receive their heat from one and the same fire chamber. In this
chamber I use waste or small coal as fuel with a blast of air on each side

page_text: which consumes all cinder and enables the heat to be kept up night and
day without any stoppage whatever from cleaning or renewing the fire.
Any number of hearths thus arranged may be placed side by side, but
I prefer to arrange them in groups of two for the purpose of welding
the blooms in the furnace clear of scale for the production of large
masses for armour, slab, girder, or rail direct, and thus save the cost
of piling. Each hearth I surround with air flues, and I form also air
flues beneath the hearths which are all regulated by inside and out-
side dampers supplying the same from the external air and allowing
them to discharge heated air into the furnace a little above the boshes of
the hearths as required. In the middle wall dividing the two lines
of hearths I form' flues for discharging in a heated state air admitted to
the furnace through openings at the base of a common vertical shaft
which serves to carry off the gases of combustion. In the bottom lining
of this shaft just below the metal mantle plate carrying the top part of
said shaft from top of cast-iron pillars I admit air which circulates along
each roof of the fire chamber for discharging in a heated state into the
rising gases and there igniting them over the fire bridge, which effects
complete combustion and gives off any kind of flame required. In the
back of each hearth at a certain height I have a tap hole for running
off slag which falls into trams in the centre of each arch. Air is allowed.
to pass over this slag along the middle wall and is discharged on to the
deflected flame of the fire-place. The boshes are made to receive
crucibles for melting the metal for conversion into cast steel and it is
also intended to employ them for receiving the ore which is ultimately to
be fused and converted into steel or puddled iron in the hearths. Above
the hearths are fitted tuyeres for blowing down highly heated air on to
the molten metal on the hearths. The furnace is fitted with puddling
holes in the large doors and closed air-tight as usual and a communica
tion under the command of the puddler is made between the hearths to
allow of metal being run from one to the other. At the vertical shaft
end of the furnace an opening is made in communication with a blast
furnace from which I take my supply of metal as it is run therefrom
direct on to the hearths of the puddling furnace, which I here purify by
its own slag and other fluxes previously refined and prepared. The heat
required for operating upon this metal may also be employed to melt
blistered steel placed in crucibles on the boshes, but when I want to
produce a good tough quality of iron direct I sometimes take calcined

page_text: oro which has been crushed into small piccos and mix it with a suitable
flux and place the same on the boshes, and so soon as the ore shows
indications of softening I rake it into the melted metal on the hearths
and smelt and puddle upon the hearth.