Improvements in and connected with Centrifugal Concentrators for Minerals, Ores, or other Dense Bodies, applicable also for Classifying Materials.
Year: 1890

page_text: Date of Application, 18th Dec., 1890
Complete Specification Left, 18th Sept., 1891-Accepted, 24th Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in and connected with Centrifugal Concentrators
for Minerals, Ores, or other Dense Bodies, applicable also for
Classifying Materials.
I THOMAS CLARKSON of Elm Tree Villa, Battersea in the County of Surrey,
Engineer, do hereby declare the nature of this invention to be as follows;-
My invention relates to improvements in centrifugal concentrators or classifiers
and the objects of my improvements are-firstly, to construct a compact receiver
adapted to catch and automatically deliver the materials with certainty and
rapidity; secondly, to provide a steady adjustable feed device; thirdly, to construct
a novel and efficient centrifugal distributor; fourthly, to afford facilities for the
rapid change of the acting parts of same to suit different bodies to be treated;
fifthly, to ensure steady running of same and to reduce friction as much as possible
of the rotary spindle of same; sixthly, to facilitate the separation of materials
which being of nearly the same specific gravity are of different chemical com-
position; and seventhly, to apply mechanism for regulating the speed of revolution
of the centrifuge.
I attain these objects by the following special constructions and mechanisms.
The receiver is formed of any required number of separate annular concentric
compartments of heights diminishing towards the inmost one and mounted upon
a bed plate. I provide in each compartment one or more sets of helical or
spiral planes or paths leading to a discharge aperture or apertures at the base.
The apices of these helices are at levels falling towards the immost com-
partment.
Centrally in the receiver is fixed an inner chamber terminating below the top of
the next outer compartment, and its base is connected to an air pipe communicating
with an exhaust fan. The receiver has an open topped cap and on it rests a tripod
supporting the feed hopper, from the base of which depends a feed pipe: at the
foot of the pipe is a conical feed valve fitted with a winged guide and operated by
a vertical screwed 'spindle working in a bush carried by a cross bar and provided
with hand wheel, lock nut, and a device for preventing rotation during its vertical
travel; thus the feed aperture can be regulated as required. At a suitable level
below the feed valve is fixed the distributor, which is composed of three parts, a
base, a loose rim, and an upper cap.
The base is fixed to the top of the driving spindle and is internally convex
centrally, concaved concentrically, and rebated circumferentially to receive the loose
rim which may be flat or inclined' upwards and downwards at any required angle:
the rim fits the base and requires no fixing though steadying pins may be employed.
its upper surface has parallel sided radial channels for the passage of material the
walls between said channels being feathered or rounded at the inner ends upon
this channelled rim rests the cap, its lower surface forming the fourth side of the
said channels, its inner part encircles the feed pipe and is of a curved form in cross
section and its outer part corresponds with the angle or lay of the loose rim; when
the rim is horizontal the cap may be fixed to it and the channels extended through
the periphery.
To change the rim to suit varying bodies the parts are so arranged that the cap
can be simply slidden up the feed pipe.
-To ensure eteady running of the spindle with a minimum of friction I apply and
use ball bearings. The lower one supports a swell or collar on the spindle and is
mounted in or on a bush in a hanger fixed below the bed plate. The upper one is
arranged in a boss supported by.a. bracket in the inner chamber and guides the

page_text: spindle between a swell or collar thereon and a bush: suitable clearances are left
and efficient means for lubrication are provided for the ball bearings. To exclude
extraneous matter from the ball bearings protecting tubes are provided, the lower
one is fixed around the spindle and the upper one is adapted to be slidden down to
admit of inspection. A driving pulley and means for adjusting the vertical position
of the spindle are provided.
To facilitate separation of materials which although of about the same specific
gravity are nevertheless some of magnetic and others of non-magnetic character in
combination with an annular receiver of known type according to my improvements
I apply and arrange adjacent to the receiver permanent or electro magnets by
which the range or flight of all the magnetic particles is augmented so that
they will be carried to a compartment further from the centre than those which are
non-magnetic.
Finally my invention comprises the combination with an apparatus such as I
have above indicated (with or without magnets) of mechanism for regulating the
speed of rotation of the driving spindle. In this combination I connect the spindle
pulley to a second pulley mounted in a long vertical bearing in a bracket on a bed
plate. The second pulley is driven by a friction wheel at right angles thereto and
mounted on a spindle so as to be capable of adjustment in regard to its radial
distance from the centre of the second pulley by a moveable fork in an adjacent
spindle.
The first spindle is driven by any suitable motor and the second is provided with
hand motion device and indicator so that no matter at what speed the motor is
running the speed of the spindle of the centrifugal machine can be regulated at will
by sliding the friction wheel upon its spindle.
Dated this 18th day of December 1890.
J. C. CHAPMAN,
Agent.
COMPLETE SPECIFICATION.
Improvements in and connected with Centrifugal Concentrators
for Minerals, Ores, or other Dense Bodies, applicable also for
Classifying Materials.
THOMAS CLARKSON Engineer, formerly of Elm Tree Villa, Battersea, but
now of Fairholme, Egmont Road, Sutton in the County of Surrey, do hereby
declare the nature of this invention and the manner in which the same is to be
performed to be particularly described and ascertained in-and. by the following
statement: :-
My invention relates to improvements in centrifugal concentrators or classifiers
and the objects of my improvements are, firstly, to construct a compact receiver
adapted to catch and automatically deliver the ejected materials with certainty
and rapidity secondly, to provide a steady adjustable feed device; thirdly, to
construct a novel and efficient centrifugal distributor: fourthly, to afford facilities
for the rapid change of the acting parts of same to suit different bodies to be
treated; fifthly, to ensure steady running of the distributor and to reduce friction
_as_much as possible of the rotary spindle. of same; sixthly, to facilitate the.
separation of materials which being of nearly the same specific gravity are of
different chemical composition; and seventhly, to apply mechanism for regulating
the speed of revolution of the centrifugal distributor.
I attain all these objects by the special constructions and mechanisins hereinafter
set forth.
The action of the distributor may be illustrated by reference to the principle of
the sling and the conical pendulum. If a body for example a particle of ore, be
revolved around a vertical axis until a certain velocity is acquired and then
liberated, the distance it will fly will be determined by its velocity, angle of

page_text: projection (whether horizontal or vertical), weight, and volume, and the resistance
of the air through which it passes, and the action of gravitation.
I am aware that distribution over the edge of rotary discs or cups and the use of
short lateral apertures therein have been tried in machines of this type but they do
not effect a good separation since in such cases the projection of a particle is not
absolutely controlled as regards velocity altitude and azimuth.
The special aim of this part of the present invention is to impart to each flying
particle exactly the same velocity and angle of projection, and also to regulate the
motion of the air through which it passes.
I will now fully describe my invention in reference to the accompanying
drawings, in which like letters indicate like parts.
Figure 1 is a vertical section of one form of distributor,
Figure 1 a constructional detail of same,
Figures 2 and 24 horizontal sections through channels arranged radially and
tangentially.
Figure 3 a vertical section through a whole machine showing arrangement thereof,
and an alternative construction of distributor.
Figure 4 a half section on line Y. Z, and half plan of Figure 3,
Figure 5 an enlarged sectional elevation, part in elevation of distributor and detail
of Figure 3,
Figure 6 section W. X. of Figure 5;
Figures 7 and 8 respectively sectional elevations at top of feed hopper and base
of driving spindle :
Figure 9 a cross section through a receiver and magnet applied to it :
Figure 10 an elevation partly in section and Figure 11 a plan partly in section
and partly broken away to show details, of speed regulator.
The receiver B Figures 3 and 4 is of cast iron or suitable material mounted on
bedplate A and divided into any required number of separate annular vertical and
concentric compartments b', 62, 63, of heights diminishing inwardly towards the
inmost or central chamber a and feather-edged at tops to facilitate entry and avoid
reflection of materials into wrong compartments. The said central chamber a is
disposed as illustrated in Figure 3 communicating through bed plate A with an air
pipe a from a fan or other exhausting device of adjustable power so that in
operation the downward air current will affect the flying particles and can, be
regulated as required to improve the separation.
For rendering the receiver self clearing and for rapidly delivering the separated
material received by the compartments, each has an inclined base in the form of
one or two helical planes as indicated at 1, h2, h3, Figure 3, the apices respectively
diminishing in height inwardly and leading to discbarge orifices a¹, a², a³, Figure 4
in bedplate A. These also form distance pieces between the walls of the cylinders:
are handholes for making joints, cleaning and so forth, and B' is an open-topped
moveable cap for avoiding extraneous draughts.
C Figures 3 and 7 is the feed-hopper supported by tripod bresting on cap B¹,
and is the feed pipe depending therefrom at or about the foot of which is
contained and arranged a conical feed valve Figure 5, this valve is maintained in
a truly central position by means of a three winged guide piece c' and it is mounted
upon and adjustable vertically by screwed spindle working in bush c³ in cross
bar c', and provided with hand wheel e and lock nut c', and prevented from rotating
during its vertical travel by the device e engaging a slot in the spindle. By this
construction an uniform and unobstructed annular feed opening is obtained the area
of which can be regulated as required.
At a suitable level below the feed valve c' is fixed the distributor around which
a number of channels d³ for the ejection of the material are arranged.
The construction of these channels d³ is important.
They extend from the interior to the exterior of the distributor and are made
long in proportion to their sectional area, which is only so much larger than the
particles to be treated as to allow of their free passage. In cross section they may be

page_text: round square or rectangular and they are parallel sided except at their inner orifices..
They may be straight as illustrated, or curved like the passages of a turbine;
They are generally arranged radially as in Figure 2, but I may sometimes adopt
the modified arrangement illustrated in Figure 2 wherein they are disposed
tangentially to a smaller circle of any required diameter described around the
centre of the distributor: The walls between the channels are featheredged or
tapered off at their inner ends as shown to facilitate entry of materials.
The construction of a distributor is illustrated in-Figures 3 and 5. It is composed
of three parts, a base d, a loose rim d', and an upper loose cap d²; The base dis
fixed to top of the driving spindle S and is preferably of the internal form
illustrated, convex centrally, concaved concentrically, and rebated circumferentially
to receive the loose rim d' which fits exactly so as to require no fixing, though
steadying pins may be employed. This internal formn is for the purpose of gradually
changing the direction of motion of the falling particles from the feed to the ejection.
The rim d' is illustrated as inclined upwards and outwards at about 45° with the
horizon, but it may be flat or inclined upwards or downwards at any required
angle.
Upon the upper surface of rim d' the channels ³ ³ are cut and arranged as
above specified. A set of rims or caps d' each having channels of different sections
(say, and of an inch square respectively) may form part of each
machine. Upon the channelled rim drests the loose cap d which in, this case
forms the fourth side and top of the channels d³: The cap is of the form shown in
Figure 5, encircling but not touching feed pipe c so as to guide the material easily
to the channels and prevent it flying out at the top its outer part is made to
correspond exactly with the angle of the 'lay of rim d' upon which it rests, and
upon rotation the parts d, d', d², revolve as one by friction alone.
2
The parts are best made in hard gun-metal or equivalent to avoid corrosion.
Referring to the alternative-or-modified construction of distributor shown in
Figure The distributor D is made in two parts; the solid-based fixed-centrally-
to top-of-spindle-S-as-before-convex or curved to a point at its centre-internally,
and the loose cap d' upon the underside of the outer part of which the channels d
are formed, the face of the base d in this case forming, the, fourth, side thereof
The cap d is of the form shown contracted.at its top-so as just to admit the feed
pipe cand expanded at its base, it is not rigidly fixed to the based but rests. by
gravity thereupon, and to prevent slip while at the same time-leaving-every-
aperture unobstructed (which is very important), the cap d' is made to project
beyond-the-base.d-all-round its periphery, the outer ends of the walls between the
channels being extended down and at suitable intervals the end of one wall is cut
away to admit of the fitting in of three lugs do Figure 1ª cast on base d,
between the two adjacent projecting walls which thus engage the lug d° and prevent
'slip of the cup d¹
The vertical position of feed pipe c is adjusted in use so that its foot and the
contained valve are just so far above the centre of the base d of the distributor
as to enable the rim to be changed when required by simply sliding cap d² up
pipe c, and replacing it after the change.
To ensure steady running of spindle S with a minimum of friction I apply and
use-ball-bearings-as-illustrated-Figures-5,-6,-and-8.-
The driving spindle S passes through a boss a' on air pipe at, and has a swell or
collar så near its foot supported by ball bearings. I running on a steel bearing
bush 2 carried in a hangers fixed below the bed plate A; is a lock nut for
adjusting the vertical position of spindles by bush s³, and lubrication is effected by
pipe p
from oil reservoir Z. The upper part of spindle S is guided only by ball
bearings E carried in boss a fixed centrally by arms in the chamber «; The
balls run between a lower swells and a fixed steel bush s, and are lubricated by
pipe p carried through arm a and boss a from the higher level oil reservoir Z
Figure 3. In both bearings E, E', clearances e e' are left between. S. and, the
bushes s², respectively. To exclude.extraneous matter such as dirt and grit,the

page_text: upper ball bearing and spindle are enclosed in a pipe Q having a bayonet joint at q
in boss a³, so that by turning it slightly it can be lowered for inspection of
bearing E¹, and in normal position illustrated it fits into but clears the base d of the
distributor. The lower part of spindle S is enclosed in fixed pipe Q' Figure 3,
and P is the belt pulley driven direct by the prime motor or as hereinafter set
forth.
To facilitate separation of materials which although of about the same specific
gravity are nevertheless some of magnetic and others of non-magnetic character
such as magnetite from copper pyrites, in combination with any type of receiver for
the purpose set forth (but which in this case must be of non-metallic material) I
apply magnets of known types by which the flight or range of the magnetic particles
is increased so that they will fly into a compartment further from the centre than
those which are non-magnetic owing to the auxiliary influence of the magnetic field.
Such a combination is shown in Figure 9 wherein M are permanent or electro
magnets suitably arranged above a known type of receiver B so as to act as above
indicated.
Finally my invention comprises the combination with an apparatus such as
have above specified (with or without magnets) of special mechanism placed in any
convenient position near the apparatus for regulating and indicating the speed of
rotation of the spindle S.
Referring to Figures 10 and 11: The concentrator is preferably mounted on
legs and in this combination the driving pulley P is connected not direct with the
prime motor as above indicated, but to a second pulley F by a belt f; This pulley F
has a disc face on its lower side and is mounted on a vertical spindle f running in
a long bearing in a frame or bracket f2 fixed to bed 3 and surmounted by a
pressure cap and lubricator / as illustrated. The disc pulley F is driven through
à friction roller G mounted at right angles therewith upon a spindle running in
bearings in the frame or bracket f2 and engaging the disc.
The spindle g is
provided with a key or feather upon which the wheel G can slide, and is driven
through pulley g¹ and belt by the prime motor.
4
Alongside of the spindle, see Figure 11 mounted in long bearing bosses in
bracket, is a second spindle K screwed at one end k the screw working in bush º,
it is provided with a hand wheel and a fork 2 which engages with groove in the
boss of the friction roller G, so that by the operation of hand wheel the fork k²
causes roller G to slide upon its spindle g to and from the centre of disc-pulley F.
A graduated scale ³ is fixed on the boss of the screwed part and a finger 4 is
fixed on spindle K sliding with same above the graduated scale k³, and thus the
speed of the pulley F and of the machine may be ascertained by inspection of the
scale. By the use of this appliance, no matter at what speed the prime motor and
spindle may run, the speed of pulley F can be regulated as required by sliding
the friction roller G upon its shaft as specified, and so the speed of the spindle S
and the distributor is regulated.
I ain aware that centrifugal concentrators or classifiers generally are not new and
that receivers with annular troughs and clearing brushes have been used and I lay
no claim to the general principles thereof, but :-
Having now particularly described and ascertained the nature of this invention
and the manner in which the same is to be performed, I declare that what 1
claim is :-
1. The construction and use in a centrifugal concentrator or classifier of the self
clearing receiver B on the bed plate A divided into separate annular vertical com-
partments of heights inwardly diminishing towards the central chamber and each
provided with two or more helical paths and discharge orifices substantially as
described and illustrated, for collecting and automatically delivering the separated
materials as set forth.
2. In a centrifugal concentrator or classifier the combination of the feed hopper C
with depending feed pipe e containing a vertically adjustable conical feed valve c

page_text: with three winged guide piece, &, spinille and means for adjusting same sub-
stantially as set forth, for ensuring an "uniform, and unobstructed annular feed
opening.
3. The construction of the centrifugal distributor.D in three parts, viz. :—the
solid base of the internal form shown fixed to driving-spindle S. the loose
channelled rim.d resting thereupon, and the loose cap d² of shape illustrated, and
all arranged and operating substantially as and for the purposes set forth.
4. In a centrifugal distributor constructed in separate parts not rigidly connected
together and where the channels are horizontally disposed, the means herein
described for preventing slip during rotation without obstructing any ejection
channel consisted in the extended walls cut away at intervals to fit the lugs don
base.d, as set forth in reference-to-Figure 14
5. In a centrifugal concentrator or classifier, the combination with a distributor I
having channels.d and mounted on its driving spindle, of the central chamber a
communicating by pipe a with an exhausting device-of-adjustable power-for
regulating the air currents, all constructed and mounted substantially as and for
the purpose set forth.
6. For ensuring steady running and minimising friction, the application to and
combination with the centrifugal distributor D and its driving spindle S of the ball
bearings E, E', having clearances e e¹, the lower set E supporting, the upper set E
guiding the said spindle S, and fitted and arranged as described and illustrated, and
protected by movable pipe Q and fixed pipe Q' all constructed and arranged
substantially as and for the purposes set forth.
7. In combination, the feed device, the distributor D, its spindle S, ball
bearings E E', the receiver B, chamber a, bed plate A, air pipe a and adjustable
exhausting device-all-disposed-constructed and combined together as a whole
machine substantially in the manner described and illustrated.
8. In-a-centrifugal concentrator-or-classifier the combination-with-the-distributor
and a surrounding-receiver-divided into separate annular compartments of
permanent or electro-magnets such as M, disposed substantially as-and-for-the
purpose set forth.
9. In a centrifugal concentrator or classifier such as is above specified as a whole,
the combination with the main driving spindle S, pulley P and its belt, of a speed
regulating appliance with hand wheel, scale, and indicating device constructed and
-arranged-to-operate-substantially-in-the-manner-and-for the purposes-described-and-
illustrated in the accompanying drawings.
ca
1001
J. C. CHAPMAN,
Chartered Patent Agent, 70, Chancery Lane, London, Agent for Applicant.