IMPROVEMENTS IN APPARATUS FOR SEPARATING ORES OR MATerials of DIFFERENT SPECIFIC GRAVITIES
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Otho Glynn Bolitho at the Office of
the Commissioners of Patents on the 22nd May 1879. .
OTHO GLYNN BOLITHO, Captain of the 3rd Prince of Wales' Dragoon Guards, of
Gort, in the County of Galway, Ireland. "IMPROVEMENTS IN APPARATUS FOR
SEPARATING ORES OR MATerials of DIFFERENT SPECIFIC GRAVITIES."
This Invention has for its object improvements in apparatus for separating ores
or materials of different specific gravities.
For this purpose I employ casings forming channels having the same breadth
throughout, or nearly so, but increasing in length from bottom to top. These casings
may be formed by two similar cones or pyramids, one inside the other, with their
axes vertical, so that by raising or lowering the inner cone or pyramid the channel
between them can be altered iu breadth when desired.
The outer casing is not brought down to a point but is truncated and connected
to a vertical chamber or tube, the connection being watertight. There may be
several such casings side by side debouching into one common chamber. This
chamber or tube is closed at the bottom, and at a point in its side or bottom it is
supplied with water from a pipe having a regulating stopcock.
Close to the bottom of the chamber there is a discharge cock by which the ores
and substances treated pass out of the chamber. When the regulating stop cock is
opened and water is allowed to flow into the chamber it will rise in the casing, its
velocity uniformly diminishing the higher it rises from the increasing size of the
channel, and on reaching the top, where it has scarcely any motion, it will trickle or
quietly flow over the outer edge of the casing into a gutter or launder. All eddying
of the water is prevented since the channel which is narrow is of the same breadth
throughout, so that the water in rising can flow laterally but in one direction. The
ores or substances to be treated flow from a launder into the whole length of the
channel at the top of the casing, and drop onto the surface of the water where there
is scarcely any motion.
There is a strip or portion partly in and partly out of the water extending all
round the top of the channel, dividing it into two parts, the ores or substances to be
treated fall onto the water in the inside part, and are thus prevented from extending
laterally and flowing at once over the edge of the outer casing. The heavier par-
ticles of the ores or substances to be treated will pass down through the casing, in

page_text: spite of the current of water, into the chamber, and pass off through the discharge
cock, while the lighter particles will at varying depths, according to their specific
gravities, encounter such a current that they cannot descend lower, there being no
eddying to suspend any particles against their natural inclination to descend.
The lighter particles sustained in the channel by the current are allowed to
descend when desired by lessening the supply of water or by widening the channel,
cither of which diminish the force of the current. The ore or matter to be treated
is not allowed to enter at the top of the channel while the diminished currents are
being used. At the end of stated periods the supply of water is altogether stopped,
permitting matter suspended by the current of water last used, i.e., the weakest
current, to pass out through the bottom tap, after which the supply of water being
again turned on fresh ore is allowed to pass into the machine. By successively
using currents diminishing in velocity, an ore can by this apparatus be separated
into various classes.
In some cases I employ orifices, the size of which may be regulated by taps, plugs,
valves, or sluices at one or more levels in the casing; through these water, and if desired,
portions of the matter under treatment can pass.
When these orifices are used the
length as well as the breadth of the channel need not vary at different levels, since
the escape of the water through the orifices will diminish the current as it flows
upwards.
For the same purpose pipes projecting into the channel with small holes on their
undersides may be used.
The casings or other parts of the apparatus may be struck with mallets as is done
in some ore dressing operations.