IMPROVEMENTS IN FURNACES FOR BURNING PYRITES.
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by James Mason at the Office of the
Commissioners of Patents on the 26th April 1881.
JAMES MASON, of Eynsham Hall, near Witney, in the County of Oxford.
"IMPROVEMENTS IN FURNACES FOR BURNING PYRITES.
"
My Invention relates to improvements in the furnaces in respect of which former
Letters Patent were granted to me dated the 4th August 1880, No. 3196, and
consists of the following features, viz.:-
1. In lieu of fixing the hopper upon the top of the furnace regulating the
admission of the material by means of a feed roller and slide, and allowing it to
drop down free behind the first cylinder, I employ a simple inclined shoot or
mouth piece, made by preference wider and deeper at its lower end than at its
upper. The shoot is placed with its lower end rather below the centre of, and a
short distance behind the first fluted cylinder of the furnace, bringing the material
in close contact with the flutes of that cylinder to be carried forward by them in
any desired quantity. The regulation of the quantity is attained by slightly
raising or lowering the shoot, so as to allow more or less material to pass between
its mouth and the flutes of the cylinder. The object of this improvement is the
more regular feeding and the avoidance of dust, which in the previous arrangement
was caused through the free fall of the materials, the dust bursting into flame
irregularly, and accumulating in the passages leading to the acid chambers. The
new arrangement obviates that loss and inconvenience. The shoot is by preference
made with very thick sides, in order to take up and retain the heat with the
object of driving out any remnant of moisture from the materials passing
through it.
The passages for the incoming products of combustion from the fire place serving
also at a later period of the process as exits for the acid gases from the furnace
are placed one on each side of the shoot, which for that purpose is made of less
width than the inside measure of the furnace bed. These passages may be regulated
by dampers. For very broad surfaces, two or three shoots may be used side by
side, and may have additional passages for the gases left between adjoining
shoots.
2. I alter the lower end of the furnace with the view to similarly reducing the
dust at that end caused in the previous arrangement by the great free drop of the

page_text: burnt ore.
With this view the chamber underneath the furnace is dispensed with,
the incline for receiving the finished ore is made much shorter and closer, the inlets
for the air are arranged in the end wall and placed at a higher level than the
furnace bed, so that the descending ore may not directly meet a current of air.
The flue for taking off the products of combustion during the preliminary heating
process of the furnace is also placed in the end wall just under the roof, and can be
either filled with a damper or be entirely closed and built up when the preliminary
heating is completed.
3. I reverse the position of the roof arches by placing their longitudinal axes
across the furnace instead of in line with the same, with the view to the better
mixing and turning over the gases and air in their passage from the lower to the
upper end of the furnace. This may be still further assisted by the insertion of
dampers or deflecting plates between the adjoining roof arches.
4. In lieu of building the bed of the furnace on an incline, it may sometimes be
convenient to form it as a series of steps. The fire-place, instead of being near the
upper end of the furnace, may be brought nearer to the centre in order to facilitate
the preliminary heating of the bed by passing the products of combustion both
under and over it.
5. In lieu of driving the cylinders all from one side, it may be convenient
sometimes to drive some from one side, some from the other, either alternately or
in groups, or they may all be driven from both sides at the same time.
In the accompanying Drawings, Figure 1 represents a longitudinal section of a
furnace constructed according to one mode of carrying out my present Invention,
and Figure 2, is a transverse section of the same. Figure 3 is a longitudinal
section illustrating another modification.
A represents the shoot as herein before described, fixed close behind the first fluted
cylinder B. The passages alternately used for; the admission of the products of
combustion from the fire place and for the exit of the gases from the furnace are
represented by the letters C, C. D is the incline at the lower end of the furnace
leading to the slide E for the withdrawal of the burnt ore; F are the passage and
holes for the admission of air; G is the flue for taking the products of combustion
out of the furnace during the preliminary heating; H are the roof arches carried
in frames for easy removal, and J the deflecting plates; K is the bed of the
furnace shewn as a plain incline in Figure 1, and in stepped form in Figure 3;
L is the fire grate.