Improvements in Apparatus for the Concentration of Minerals by Means of Compressed Air.
Year: 1895

page_text: S
Date of Application, 8th Mar., 1895
"
75
A
1000
Date of Application, 8th Mar., 1895
Complete Specification Left, 9th Dev., 1695-Accepted, 19th Jan., 1900
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for the Concentration of Minerals by
Means of Compressed Air.
I, JOHN CORRY FELL, of 3 College Road, Chalk Farm, N.W. Engineer do
hereby declare the nature of this invention to be as follows:-
This invention relates to apparatus for the concentration of minerals in the
process of their separation from their matrix, and has for its object the provision
of means whereby this result is effected in a simple and expeditious method, through
the medium of compressed air.
My invention consists in the combination of au air forcing device; a uniform
feeding device, for delivering a uniform amount of ground or crushed material,
containing the mineral, to the concentrating device; a concentrating device con-
sisting of a conical tube, adjustable as to inclination, having a longitudinal slot
arranged from end to end; and a divided receptacle to receive the material of
various grades from the slot of the conical tube. A sieve or similar sizing device
may also be combined with the conical tube and divided receptacle, for the better
sizing of the delivered material from the slot of the conical tube.
I. may, if
necessary, arrange a second concentrating device in connection with the conical
tube, which consists of a vertical tube attached to the main conical tube, around
which is arranged a second tube of larger diameter and greater length, so as to
form an annular space between the two tubes.
The principle upon which my machine works, is the action of gravity upon the
particles of various specific densities and volumes (of which the material to be
treated is composed) which have had momentum imparted to them by a current of
air, so as to locate their position of deposit, according to their respective grades.
The force of the wind blast, the length of travel, and retardation of gravity, being
capable of easy adjustment by my improved apparatus.
To carry my invention into effect, I arrange a fan or air forcing appliance upon
a suitable support, and I connect to this fan, by a flexible connection, such as
canvas hose, a conical tube which is mounted upon a support, preferably by a
hinge, so that its angle with the horizontal line may be altered as desired.
This conical tube has its smaller end connected to the fan, while its larger end
projects upward in a slanting direction. The lower side of this tube has a slot
arranged along the greater part of its length. Below the slot is a receptacle of
box formation which is attached to the conical tube, and serves to receive the
concentrated mineral after it has passed through the slot. This box is divided, in
its length, into compartments, by division plates, and the compartments are provided
with exit passages.
Within the receptacle I arrange a sieve, which is adapted to
slide longitudinally upon supports, a reciprocatory movement being produced by
are eccentric operated by any suitable mechanism, drawn from any convenient
source of power. The conical tube is supported at its upper end, so that its angle
can be adjusted as desired, according to the class of material being treated, or the
result desired. At the lower end of the conical tube a uniform feeding device is
arranged through which the crushed material is fed to the conical tube through a
pipe. At the upper end of the conical tube I may arrange a secondary concer-
trating device, which consists of a tube attached to the conical tube, so that
whatever the angularity of the conical tube may be, the tube always stands vertical.

page_text: Around this vertical tube, I arrange a second tube, of larger diameter and greater
height, so that an annular space is left between the two tubes. The second tube
has a slanting bottom, which makes a sliding joint with the first vertical tube, so as
to move vertically. I may arrange one or more blow pipe nozzles, which are
connected to the supply of compressed air within the secondary concentrating
device. This apparatus may be operated with or without the secondary con-
centrating tubes. I will first describe its operation without the said tubes.
The fan is started, which forces a current of air up the tube; the material
which is crushed is fed at a uniform rate from the feeding device into the conical
tube, and meeting the current of air is thereby set in motion in an upward angular
direction. Now as the tube is conical in form, it follows that the velocity of
the air, as it proceeds up the tube, must be decreased proportionately as the area
is increased; and consequently its effect upon the material becomes less and less,
as the material travels up the tube, with the result that the mineral and material,
of high specific gravity, first drops from the current of air out of the tube through
the slot into the first division of the receptacle; and the pieces of less specific
gravity are carried up higher, until they in turn fall out of the current and are
deposited in the receptacle according to their grade. The light material is carried
out at the upper end of the conical tube into the surrounding atmosphere. It is of
course necessary to adjust the angle of the tube in relation to a horizontal line
and also the pressure of the air, according to the material being treated and the
degree of concentration required.
If with the residue that is blown out at the end of the tube any valuable ore is
included, the end of the tube is lifted by its lifting gear, thus altering its angle,
which is equivalent to lengthening it, the material then offering greater resistance
to upward motion against the current of air, which tends to force it in an upward
direction.
The second method of working consists in concentrating simultaneously in the
conical tube and the tubes of the secondary apparatus.
To do this the end of the conical tube is closed with canvas, or in any other
equivalent manner, and the air and material, after passing up the conical tube,
passes up to the secondary apparatus. The column of air laden with the lighter
particles of the material then rises in a vertical column, through the first vertical
tube, and when it emerges from the top end of the said tube into the second tube
of larger diameter, the air pressure suddenly drops, and the particles gradually
become retarded in their passage upward, and as they cannot fall back again
through the first tube they take a sideward direction out of the current and fall
into the annular space between the tubes, and slide down the slanting bottom into
any suitable tube or exit. The residue of light particles in the air column are
of course delivered upwards into the surrounding atmosphere. If however, any
valuable constituents are being thrown out with the residue, the second tube is
raised by means of its lifting gear, until such a position has been obtained, that
the whole of the valuable constituents are delivered down the annular space
between the tubes. This 2nd method of concentration is recommended when
working gold ores, or when the grindings are very fine. In order to increase the
action of the air in the tubes when found necessary, I use one or more of the
blow pipe nozzles, fed with air from the fan, to produce an inductive effect on
the column of air. Referring now to the sieve, which is fitted with different
kinds of wire-cloth, graduated in mesh according to the compartment of the
receptacle over which it is situated. The object of the sieve is to concentrate the
ore by volume after having been concentrated by deusity in the conical tube. As
a matter of fact the crushing and grinding is never altogether uniform, grains
more or less equal in weight, but of different sizes, are delivered to each section,
the largest particles being of stone or iron, and which, on account of their hard-
ness remain larger than the rest of the material during grinding. The sieve
therefore prevents the passage of these larger grains into the receptacle over which
they have dropped, but which by its angular disposition and jigging motion shakes

page_text: the grains down, until they reach a mesh large enough to allow them to pass into
the proper compartment of the receptacle. Naturally the ore obtained in the
2nd and 3rd sections is less pure than that of the 1st section, as usually happens
in other concentrating machines, but I have found that my machine much improves
the grade. It is obvious that the ores of the second and third sections can be
further purified up to the grade of the first section by passing them through
another similar machine properly adjusted both in inclination and air pressure to
produce the desired result.
Dated this 8th day of March 1895.
FELL & WILDING,
I Queen Victoria Street, London, E.C., Agents for the Applicant.
Improvements in Apparatus for the Concentration of Minerals by
Means of Compressed Air.
I, JOHN CORRY FELL, of 3 College Road, Chalk Farm, London, Engineer,
do hereby declare the nature of this invention and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :--
This invention relates to apparatus for the concentration of minerals in the
process of their separation from their matrix, and has for its object the provision of
means whereby this result is effected in a simple and expeditious method through
the medium of compressed air.
My invention consists in the combination of an air forcing device, a uniform
feeding device for delivering a uniform amount of ground or crushed material
containing the mineral to the concentrating device, a concentrating device consisting
of a conical tube adjustable as to inclination having a longitudinal slot arranged
from end to end, and a divided receptacle to receive the material of varions grades
from the slot of the couical tube. A sieve or similar sizing device may also be
combined with the conical tube and divided receptacle, for the better sizing of the
delivered material from the slot of the conical tube. I may, if necessary, arrange
a second concentrating device in connection with the conical tube, which consists of
a vertical tube attached to the main conical tube around which is arranged a second
tube of larger diameter and greater length, so as to form an annular space between
the two tubes.
The principle upon which my machine works is the action of gravity upon the
particles of various specific densities and volumes, (of which the material to be
treated is composed) which have had momentum imparted to them by a current of
air, so as to locate their position of deposit according to their respective grades.
The force of the wind blast, the length of travel and retardation of gravity being
capable of easy adjustment by my improved apparatus.
In order that my invention may be the better understood I will now proceed to
describe the same in relation to the accompanying drawings, reference being had
to the letters and figures marked thereon. Like letters refer to like parts in the
various figures.
Figure 1 is a side elevation of my apparatus.
Figure 2 is a transverse section of the main tube on the line X X in Figure 1.
Figure 3 is a plan of the sorting receptacle under the main tube.
To carry my invention into effect I arrange a fan or air forcing appliance A
upon a suitable support, and I connect to this fan A by a flexible connection B,
such as canvas hose, a conical tube C, which is mounted upon a support D,
preferably by a hinge d, so that its angle with the horizontal line may be altered
as desired.

page_text: This conical tube C has its smaller end E connected to the fan A, while its
larger end e projects upward in a slanting direction. The lower side of this tube C
has a slot Farranged along the greater part of its length shown in Figure 2.
Below the slot F is a receptacle G of box formation which is attached to the
conical tube C, and serves to receive the concentrated mineral after it has passed
through the slot F. This box is divided in its length into compartments g¹ g²
and by division plates H and the compartments are provided with exit
passages 2 and 3 respectively. Within the receptacle G I arrange a sieve [
which is adapted to slide longitudinally upon supports K, a reciprocatory movement
being produced by the eccentric k operated by the mechanism L, driven from any
convenient source of power. The tube C is supported at its upper end by a rope M
passing over a pulley m or by any other equivalent device, so that its angle can be
adjusted as desired, according to the class of material being treated or the result
desired. At the lower end of the tube Ca uniform feeding device N having a
hopper is arranged through which the crushed material is fed to the tube C through
the pipe n.
This feeding device may consist of a ribbed or toothed wheel O
adapted to revolve by means of the mechanism L in the exit orifice of the hopper.
At the upper end of the tube C I arrange a secondary concentrating device P
which consists of a tube Q attached to the tube C by a hinge and telescopic
shield or flexible attachment q', so that whatever the angularity of the tube C may
be, the tube always stands vertical. Around this tube Q1 arrange a second
tube R of larger diameter and greater height, so that an annular space
left
between the two tubes Q and R. The tube R has a slanting bottom ŕ which makes
a sliding joint with the tube Q. The tube R is suspended by a rope passing
over a pulley or other equivalent device, so that the height of the top edge of
the tube R above the top edge of the tube Qmay be adjusted at will, and that the
tube R always remains vertical and concentric with the tube Q. At the extreme
lower end of the tube R an exit orifice with pipe S is provided, and within the
tube QI arrange one or more blow pipe nozzles T, which are attached to the
pipes TT led up within the receptacle G and connected to the supply of
compressed air. This apparatus may be operated with or. without the secondary
concentrating tubes Q and R. will first describe its operation without the said
tubes. The fan A is started which forces a current of air up the tube C, the
material which is crushed is fed at a uniform rate from the hopper N by the feeding
device O into the tube C, and meeting the current of air is thereby set in motion
in an improved angular direction. Now as the tube C is conical in form, it follows
that the velocity of the air as it proceeds up the tube C must be decreased
proportionally as the area is increased, and consequently its effect upon the material
becomes less and less, as the material travels up the tube with the result that the
mineral and material of high specific gravity first drops from the current of air out
of the tube C through the slot F into the first division g' of the receptacle G, and
the pieces of less specific gravity are carried up higher until they in turn fall out
of the current and are deposited in the receptacle G according to their grade.
The light material, being carried out at the end e of the tube C into the surrounding
atmosphere. It is of course necessary to adjust the angle of the tube C in relation
to a horizontal line, and also the pressure of the air, according to the material
being treated and the degree of concentration required.
If with the residue that is blown out at the end e of the tube Cany valuable ore
is included, the end of the tube is lifted by its lifting gear M m, thus altering its
angle, which is equivalent to lengthening it, the material then offering greater
resistance to upward motion against the current of air which tends to force it in
an upward direction.
The second method of working consists in concentrating simultaneously in the
tube C and the tubes Q and R. To do this the end e of the tube C is closed with
canvas or in any other equivalent manner, and the air and material after passing
up the tube C passes up through the tube Q. The diameter of this tube Q is
slightly larger than the lower end E of the tube C. The coarser and heavier

page_text: constituents of the material are separated by the tube C as hereinbefore described.
The column of air laden with the lighter particles of the material then rises in
a vertical column through the tube Q and when it emerges from the top end of the
tube Qinto the tube R of larger diameter, the air pressure suddenly drops and
the particles gradually become retarded in their passage upward, and as they
cannot fall back again through the tube Q they take a sideward direction out of
the current and fall into the annular space between the tubes Q and R, and slide
down the slanting bottom into the tube S. The residue of light particles in the
air column are of course delivered upwards into the surrounding atmosphere. If,
however, any valuable constituents are being thrown out with the residue, the
tube R is raised by means of its lifting gear r², until such a position has been
obtained when the whole of the valuable constituents are delivered down the
annular space between the tubes Q and R. This 2nd method of concentration is
recommended when working gold ores, or when the grindings are very fine. In
order to increase the action of the air in the tubes Q and R, when found necessary,
I use one or more of the blow pipe nozzles T fed with air from the fan A, to
produce an inductive effect on the column of air.
Referring now to the sieve I which is fitted with different kinds of wire cloth
graduated in mesh according as to which compartment of the receptacle G it is
situated over. The object of the sieve I is to concentrate the ore by volume after
having been concentrated by density in the tube C. As a matter of fact the
crushing and grinding is never altogether uniform, grains more or less equal in
weight, but of different sizes, are delivered to each section, the largest particles
being of stone or iron, which on account of their hardness remain larger than the
rest of the material during grinding. The sieve I therefore prevents the passage
of these larger grains into the receptacle over which they have dropped, but which
by its angular disposition and jigging motion, shakes the grains down until they
reach a mesh large enough to allow them to pass into the proper compartment of
the receptacle G. Naturally, the ore obtained in the 2nd and 3rd sections is less
pure than that of the first section, as usually happens in other concentrating
machines, but I have found that my machine much improves the grade. It is
obvious that the ores of the second and third sections can be further purified up
to the grade of the 1st section by passing them through another similar machine
properly adjusted both in inclination and air pressure to produce the desired
result.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
Ist. A machine for concentrating minerals consisting in combination of an air
forcing appliance, a conical tube having a longitudinal slot arranged from end to
end and connected at its smaller end to the air forcing appliance, means for
adjustment of the angle of inclination of the said tube, a feeding device adapted
to deliver a uniform quantity of crushed material to the smaller end of the conical
tube, and a receptacle divided in its length into compartments arranged below the
said slot of the conical tube to receive the concentrated mineral in various grades,
substantially as described.
2nd. In a machine for concentrating minerals the combination of an air forcing
appliance a conical tube having a longitudinal slot arranged from end to end, and
connected at its lower end to the air forcing appliance, means for the adjustment
of the angle of inclination of the said tube, a feeding device adapted to deliver
a uniform quantity of crushed material to the smaller end of the conical tube, and
a receptacle divided in its length into compartments arranged below the said slot
of the conical tube, with a sieve fitted with sections of varying mesh, disposed in
an angular position between the said slot of the conical tube and the said divided
receptacle, and means for jigging the sieve to classify the material as to size,
substantially as described.

page_text: 3rd. In a machine for concentrating minerals the combination of an air forcing
appliance, a conical tube having a longitudinal slot arranged from end to end and
connected at its lower end to the air forcing appliance, means for the adjustment
of the angle of inclination of the said tube, a feeding device adapted to deliver
a uniform quantity of crushed material to the smaller end of the conical tube,
and a receptacle divided in its length into compartments arranged below the
said slot of the conical tube, with a vertically arranged tube adjustably attached
to the exit of the said conical tube, a second tube of larger diameter and greater
height, arranged concentrically about the said vertical tube and adapted to slide
telescopically thereon, leaving an annular space between the said two tubes, ending
with an inclined bottom and exit orifice, and means for the adjustment of the two
tubes relatively to one another, substantially as described.
4th. In a machine for the concentration of minerals the combination of an
air forcing appliance a conical slotted tube connected thereto at its smaller end,
and a vertically arranged tube attached to the exit of the said conical tube, a
second tube of larger diameter and greater height, arranged concentrically
about the said vertical tube and adapted to slide telescopically thereon, leaving
an annular space between the said two tubes, ending with an inclined bottom and
exit orifice, and means for the adjustment of the two tubes relatively to one
another, with one or more blow pipe nozzles within the inner tubes, and means
for their connection with the air forcing appliance, substantially as described.
Dated this 9th day of December 1895.
FELL & WILDING,
1 Queen Victoria Street, London, E.C., Agents for the Applicant.