Improvements in Electro-magnetic Apparatus for Separating Ores.
Year: 1899

page_text: Date of Application, 8th Feb., 1899-Accepted, 8th Feb., 1900
COMPLETE SPECIFICATION.
Improvements in Electro-magnetic Apparatus for Separating Ores.
I, EMIL KREUSER, of Mechernich (Rhine Province), in the Empire of Germany,
Retired Director of Royal Mines, 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 an improved construction of apparatus for separating
or sorting ores by electromagnetic action which is mainly distinguished from
known apparatus of this class having cylinder shaped electro magnets in that
two magnets the core of which is of an I or I shaped longitudinal section, are
made to revolve in contrary directions relatively to each other with their poles
of opposite sign presented towards each other. The operative magnetic fields
produced in this way are essentially different from those of known apparatus.
By the present invention the magnetic lines of force are directly generated
in the revolving iron cores and pass into the polar surfaces which are the work-
ing surfaces. Their path is therefore of the smallest possible extent and the air
resistance of the fields is very small so that the electrical energy expended is
mainly converted into magnetic intensity which is solely expended in attracting
the magnetic substances to be sorted whereas with other constructions the expen-
diture of magneto motoric tension results in a considerable loss of power. In
my improved apparatus there are no auxiliary magnets and no magnetic axial
resistances or the like.
A farther improvement in which my apparatus differs from existing ones
consists in the arrangement of the magnets in a direction either vertical more
or less inclined one above the other.
This arrangement of the magnets possesses the great advantage that the ore
is led along a fixed supporting surface into the magnetic field, so that it is not
subjected to the action of gravity operating contrary to the magnetic attrac-
tion until the moment when it is subject to the magnetic action. This arrange-
ment necessitates a farther improvement. Under ordinary circumstances, the
particles of ore to be passed between two magnetic poles are subject to the
influence of both poles, so that only the difference of attraction between the two
is operative.
In order now to render it possible that only the attraction of the upper pole.
shall be fully brought into play, the lower pole is according to the present inven-
tion tightly enclosed in a material that is a diamagnetic or a bad conductor of
magnetism and is of at least the same thickness as the existing air space between
the magnet cylinders.
In order to utilize the magnetic field thus produced directly for the separation
of the ores, there are introduced into it superposed inclined planes which catch
the several magnetic substances passed between the magnets.
Each of the particles attracted by the cylindrical poles will be retained thereby
until the action of gravity thereon exceeds the magnetic attraction, so as to
cause it to fall off the pole. As the attracted particle, in consequence of the
rotation, passes from the strongest magnetic field to a gradually decreasing one,

page_text: the superposed inclined planes will receive the ores of different magnetic per-
meability, the ores of stronger magnetic property being delivered on the upper
planes and those of weaker magnetic action on the lower ones.
Owing to the advantagous nature of the magnetic field the apparatus is
rendered applicable for the magnetic extraction of every kind of magnetic ore
without exception.
For such extractions magnetic fields are produced of such strength that the
cylinders exercise a very strong attraction upon each other. It has not hereto-
fore been possible to overcome this action of powerful rotating magnets upon
each other, this disadvantage is also overcome by the present invention.
For this purpose there are provided on the ends of the cylinders or at interme-
diate points beyond the windings thereof, special rings of nonmagnetic metal such
as copper brass papier mache &c. which maintain the cylindrical poles at the proper
distance apart, the outer diameter of these rings depending upon the necessary
distance to be maintained between the poles. On supplying the electrical cur-
rent to the magnets, these rings are pressed firmly against each other and thus
insure the correct distance between the cylinders. At the same time they serve
the purpose of freeing the bearings of the cylinder journal from excessive
pressure. The frictional pressure of the one ring against the other is utilized
by causing the rings of the one cylinder to act as frictional gearing for driving
the other one, thus doing away with the toothed gearing heretofore employed
for this purpose, and which is liable to several objections in particular with
highly concentrated magnetic fields.
The outer diameters of the said pressure rings need not necessarily be the
same, on the contrary, it is often of advantage to impart to the one cylinder a
quicker rotation than the other and this can easily be done by suitably pro-
portioning the said rings, which can be readily changed.
Lastly, a farther improvement consists in forming the cylinder magnets with
flutings or milling. This is based upon the observation that the magnetic cur-
rent, like the electric current passes more readily from the conductor to the air
through points or sharp edges. Hence the Huting or milling of the cylindrical
pole suriaces has proved to be most suitable for concentrating the magnetic lines
of force. As these lines of force, do not issue in broad surfaces, but in sharp
lines, the concentration, can by the above means, be brought to a maximum.
I will describe the manner of carrying my said improvements into effect with
reference to the accompanying drawings.
Figs. 1, 2 and 3 show one construction of the apparatus respectively in a
cross section through the magnet cylinder on line Y-Y' Fig. 2, a longitudinal
section on line Z-Fig. 1, and a sectional plan on line X-Fig. 1, Figs. 4,
4 and 5 show the connection of the axes or journals with the cylinders and the
mode of fixing the distance rings while Fig. 4" shews a separate distance ring
Fig. 6 shows a pair of cylinders with iron cylindrical cores of a T shaped
section and shewing the mode of coiling.
E
Figs. 7 and show the detail construction of the arrangement for receiving
and transporting the attracted particles of ore.
The pair of cylinders is mounted, in the construction shown, upon a wood
framing. The lower cylinder, that is to say, the one shaped with iron core of I
section is marked with A and the upper one with A¹ while B and B indicate
the journals by which the cylinders are carried in bearings L, L'.
The journals are preferably made of nonmagnetic material such as brass
papier mache vulcanite and the like. For the better securing thereto of the
iron cylinders, they are formed with disc shaped inner ends F fitting into corre-
sponding recesses in the ends of the cylinders, which discs are strengthened by
ribs and have an outward projecting rim f as shewn in Figs. 4 and 4 serving
as support to the distance rings D and D. These rings are secured by screws s
to the discs F and iron cylinders A, while the journals B, B' are also secured to
the iron cylinders by other screws s¹.

page_text: The outer diameter of the distance rings can, as before stated, be either of
the same diameter or of different diameters for the two cylifiders; thus for
instance in Fig: 4 the outer diameter of the ring D is smaller than that of D.
In this case therefore the cylinder A would rotate with a quicker speed than
the lower cylinder A. In Fig. 6 both cylinders have distance rings of the same
outer diameter, so that the cylinders revolve at the same speed.
Fig. 4 shows a distance ring separately. The drawing does not quite corre-
spond with the actual construction, as it is only intended to show the mode
of fixing of the ring to the disc of the journal....
Fig. 4 shows a special arrangement of the distance rings.
On the cylindrical polar surfaces of the lower cylinder A are fixed the cover-
ings a of diamagnetic material. These must at least have a thickness equal to
one half the distance between the two cylinders, that is to say, the polar. dis-
tance P.
W, W designate the windings of covered conducting wire on the two cylin-
ders d is the conducting wire passing from the dynamo machine or other source
of electrical energy to the winding and passing back again to the dynamo, g are
passages through which the wire leads are introduced into the iron cylinders,
that is to say for entering into or passing out from the space in which the winding
is situated.
The supply of the electric current into and from the winding is effected by
insulated contact rings r¹ and brushes b₁ 62 63 64. The action of the
arrangement shown in Figs. 1, 2 and 3 is as follows:-
The suitably crushed ore H is introduced into the hoppers T. From these it
passes into the smaller hoppers t situated immediately over the cylindrical polar
surfaces of the lower cylinder.
These smaller hoppers are provided with an adjustable slide Y in order that
the quantity of ore supplied may be accurately regulated and be entirely cut off
when required. The supply of ore to the polar surfaces is effected by the rota-
tion of the cylinders. The lower cylinder receives its rotary motion in the
direction of the arrow by means of the separate belt pulley S, on whose shaft
is fixed the pinion gearing with the toothed wheel Z on the journal of the
lower cylinder, thus imparting rotation to the latter.
When the electric current has been supplied to the windings the polar sur-
faces of the two cylinders exercise an attraction upon each other.
The tendency to approach is prevented by the distance rings D and D' fixed
to the ends of the cylinders. These rings are applied firmly against each other
so that on the rotation of the lower cylinder the upper one is rotated with it in
the contrary direction. When rotary motion has been imparted to the cylinders,
the pulverulent ore issuing from the hoppers t will soon be brought into the
strongest magnetic field existing between the two opposite polar surfaces. The
upper cylinder A', which is provided with fine flutings or milling, here attracts
the magnetic particles from the mass of ore, and on account of their rotation
carry them upward, while the particles that are not attracted remain on the
lower cylinder and gradually slide off the same. These are received by the
receptacles E and which in order to prevent the flying about of dust, are
made to encircle nearly the whole of the lower cylinder. From the receptacle
they fall through a funnel shaped opening into the sacks N¹N³ placed beneath
the apparatus. The attracted particles adhere more or less closely to the upper
cylinder according to their magnetic properties. In many cases therefore it is
necessary to provide an arrangement which enables the attracted particles to be
caught up immediately after they have left the strongest magnetic field in order
that they may not fall back into the original non-magnetic mass. A ready and
efficient receiving device for these particles is therefore a very essential requi-
site for the action of the apparatus. The requirements of this are fulfilled by
the construction shown at Figs. 7 and 8 to an enlarged scale. It consists of two
trough shaped sheet metal shoots RR which must be at least as broad as the

page_text: polar surfaces of the cylinders. Each shoot is closed at the lower end while at
the upper end they are not closed. The shoots are so fitted into each other that
between the bottoms thereof a sufficient free space is left. The sides of the
lower shoot R¹ are cut out at the upper end, as shown, in order that they may
reach up to the strongest magnetic field between the polar surfaces. On the
back surface of the shoot is a toothed rack k gearing with a pinion i so that by
turning the latter both shoots can be adjusted nearer to or farther from the
strongest magnetic field. The lower shoot carries at the closed lower end arm
shaped extensions h which are provided with a slot into which take screws fixed
to the sides of the upper shoot R2 where they can be secured in an adjustable
position by means of the screw nuts m. The upper shoot can therefore be
adjusted either independently of or together with the lower shoot.
The shoots are mounted in such an inclined position upon the wooden framing
that the ore will slide down the same by gravity. At the lower closed ends of
the shoots are funnel shaped openings 002 communicating with pipes ele².
From these openings and pipes the ore is led into special collecting sacks M¹
and M². As the width of the cylindrical polar surfaces only depends upon the
size of the iron cylinder, and the size of the iron cylinder whether of I or of I
shaped section, is only determined by conditions of suitability the polar surfaces
can be made of considerable width. As furthermore there is such a polar surface
at each end of the cylinder magnets both of which can be usefully employed
the apparatus exceeds in its output or useful effect any of the similar construc-
tions now in use.
The above described electro-magnetic orc separators can also be used in a
modified form which only differs from that above described in that the lower
cylinder is not made magnetic. In that case it only serves as an armature for
conducting the magnetic lines of force and consequently the diamagnetic cover-
ing for the lower polar surfaces, which was described in the first arrangement
can be dispensed with. The surfaces of the lower cylinder must however have
no flutings or milling, these being formed only on the polar surfaces of the
upper magnetic cylinder.
A further modification as regards the form of the cylinders of the above
described apparatus is shown in Figs. 9, 9ª 10, 11 12 and 13. The ore separator
consists in this case, as in the former case, of two oppositely revolving cylinders,
which constitute electromagnets having their polar ends of the same sign. The
electromagnet wound in this manner receives at its middle a following pole of
the opposite sign which has a greater or smaller cross section than the poles at
the ends. The rotating cylinders thus either touch each other with these middle
poles as at Figs. 10 and 11 or with the end poles as at Figs. 9 and 9ª. The
advantages which this construction affords consist firstly in the absence of the
before described distance rings, and secondly the decrease in length of the
magnetic lines of force which only have to pass a single air resistance, as will
be seen from the direction of the magnetic currents indicated by dotted lines
in Figs. 9 and 10.
The apparatus can also be so constructed that one of the cylinders only acts as
an armature and has no winding. For varying the polar distance with this
construction, the end poles can be formed with a certain amount of inclination
or taper as indicated at Fig. 12, or special rings w may be fitted over the end
poles as shown at Fig. 13 by the employment of which the polar distance is
increased while by removing them it is decreased.
The above described distance rings for maintaining the polar distance as also
the other improvements described can be applied to known constructions of ore
separators in which pairs of cylinder magnets are employed. In this case only
one cylinder is provided with special outer driving gear and the plane in which
the axes of the two cylinders are situated is arranged either in a vertical or
inclined position. The upper cylinder is provided with flutings or milling and
the lower one is provided with a covering of diamagnetic material of a thick-

page_text: ness equal to at least one half the polar distance of the opposite dissimilar poles.
By this means the useful effect of existing apparatus can be considerably
increased, and they will also then be rendered applicable for treating ores of
any kind.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. An electromagnetic ore separator consisting of two opposite revolving
iron cylinders of I or I shaped section and wound as bar magnets, the said
cylinders being arranged either vertically or in an inclined position one above
the other and the polar distance between the cylinders being maintained by
means of abutting distance rings serving as frictional gear for transmitting the
rotary motion imparted to the one magnet cylinder to the other one. so that by
employing distance rings of different diameters for the two cylinders their rela-
tive speeds can be correspondingly varied, substantially as described.
2. In an electromagnetic ore separator such as is referred to in the first claim,
forming the polar surfaces of the upper cylinder with flutings or milling and
covering the polar surfaces of the lower cylinder with diamagnetic material in
order to increase the magnetic action of the upper roller upon the ore in com-
bination with inclined shoots for receiving the separated ores, which shoots are
adjustably arranged to extend to the strongest magnetic field between the
cylinder magnets substantially as described.
3. In an electromagnetic ore separator, such as is referred to in the preceding
claims, arranging the magnet cylinders both with end poles and with an inter-
mediate pole which is made of a less diameter or greater diameter than the end
poles, whereby the separate polar distance rings are dispensed with, substan-
tially as and for the purpose described.
4. In an electromagnetic ore separator operating with two magnet cylin-
ders, increasing the useful effect of the pair of magnet cylinders by arranging
them vertically or in an inclined position one above the other and combining
therewith a diamagnetic covering for the lower cylinder poles, on to which the
crushed ore is directly delivered, the upper cylinder alone serving to attract
the ore and having its polar surfaces formed with flutings or milling while the
distance between the poles of the cylinders is regulated by polar distance rings
which at the same time serve to transmit the rotary motion from the one magnet
cylinder to the other, substantially as described.
1
T
P
1900