Improvements in or appertaining to Grinding or Pulverising . Machines.
Year: 1894

page_text: Date of Application, 18th May, 1894
Complete Specification Left, 16th Feb., 1895-Accepted, 6th Apr., 1895
PROVISIONAL STEUIFICATION.
Improvements in or appertaining to Grinding or Pulverising
. Machines.
I, CARL WEGENER of 14 Gitchinerstrasse, Berlin in the Empire of Germany,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has for its object a system of grinding or pulverising machines,
which system consists in arranging a number of separate mills or grinding
appliances of any suitable kind in stages or tiers one over another in a common
casing or frame dust tight to the outside, in such a way that the substance to be
ground passes through the several stages from the top to the bottom, a separation
and removal of the finished product being simultaneously effected by a current of
air passing from below upwards, that is to say, in an opposite direction to that of the
material which is to be ground. The removal of the finished product may also take
place from the uppermost only or from any other of the stages. The kind of
grinding apparatus employed is also immaterial, whether they be ordinary millstones,
vertical millstones or ball mills, or otherwise consist of a combination of these or
other systems.
The arrangement consists of an upright cylinder built of rings which is closed
above and below by a cover and a bottom piece respectively. A vertical shaft
driven by a worm wheel and endless screw, traverses the apparatus from top to
bottom and carries a number of dish-shaped discs corresponding to the number of
the said rings. These discs are provided on their outer periphery with ring-shaped
grinding surfaces, which latter, in combination with fixed bevelled rings supported
on projections provided on the cylinder rings, form the running surfaces for the
balls. There remains between the fixed conical rings and the rotating disc rings
an annular interstice through which the more or less finely subdivided material
falls onto the next series of balls in order to be further pulverised. On the rotation
of the shaft and consequently of the discs thereon the balls will necessarily make
a rolling movement in the gutter formed by the running surfaces, and thereby
disintegrate the material which is to be ground, which then falls between the rollers
and the running surfaces. The material to be ground, delivered through the mill
hopper which is provided with a closing slide or valve, comes first into the topmost
stage, and after sufficient pulverisation passes through the interstice into the next
stage where it is further pulverised and so on until after leaving the lowest stage it
reaches the bottom and is forwarded by conveyors or scrapers to the exit and from
thence by a pipe to an elevator. This latter again raises the still insufficiently
pulverised material and discharges it through a pipe again onto the uppermost
stage of the mill. It is thus evident that material which has not been ground
cannot leave the mill.
The separation of the sufficiently ground material from the coarser particles is
effected by means of a current of air produced by means of a fan, which current of
air is conveyed through a pipe to the bottom of the apparatus, that is to say,
under the lowest stage. There is thus introduced into the interior of the
apparatus, a current of air rising upwards from the bottom, which is preferably of
sufficient strength to convey with it the ready ground material or finished product
through the interstices of the parts of the mill to the uppermost stage or tier and
from thence through an exit pipe to a collecting chamber. The floor of the latter

page_text: is provided with openings having rings or spouts to which sacks may be fastened
from beneath. These openings may be provided with covers which may be opened
or closed by means of levers, so that, during the changing of a full sack for an
empty one, the collecting chamber may be closed to the outside. If it be not
desired to run the dust or powder directly into sacks, it may be blown through exits
out of each stage into a collecting pipe, and thence to a conveying worm, which
then conveys it direct to the place where it is to be used or stored.
In order that the bearings which are placed in
vertical shaft may not be fouled or damaged by the the roof and floor for the
is employed
--
the following arrangement
Rings are attached (concentrically to the vertical shaft) to the under side of the
cylinder cover and to the under side of the lowest rotating disc and these rings
fit loosely into rings of a U-shaped section arranged on the base of the cylinder
and on the shaft or the uppermost rotating disc. If these grooves be filled with
mercury, a thoroughly dust-tight joint is formed, as it cannot be affected by the
slight wind pressure, and the bearings are thoroughly protected from the action of
the dust which often has a grinding effect, as this dust is always lighter than the
mercury in consequence of the greater specific gravity of the latter, and thus
cannot pass through the mercury to reach the inner side of the rings.
The apparatus may be modified so that the balls travel on slightly conical
downwardly inclined running surfaces, and, further, be loaded by grinding-discs
which rotate with the main shaft, but which have a free vertical adjustment
thereon.
The top or back of these weighting discs must, of course, be of such a shape that
the material which is to be ground slips off it downwards, and is thus conveyed
to the next stage or tier. The fixed conical running surfaces which rest on annular
projections must in this case have so large a central hole that there remains
between them and the shaft sufficient room to allow of the material to be ground
falling through. On the top or back of the rotating grinding discs, the material
again reaches the outer wall of the cylinder, and falls into the annular interstice
which is enclosed by these discs and the cylinder, and onto the next grinding
surface. This arrangement may be combined with vertical millstones which may
either be attached to the rotating grinding discs so that they grind on the fixed
running surfaces whilst their side surfaces run on balls, or the vertical mill stones
may be held in a fixed support so that they travel on the rotating running surfaces
whilst again their side surfaces travel on balls.
In these latter cases, the axles of the vertical mill stones may be inclined or
they may be arranged to stand vertically fixed on the rotating running surfaces
for the balls, on which latter the side faces of the rollers may travel, whilst the
peripheral surfaces grind on the inner surfaces of the rings of the casing.
In another form of construction the mill arrangement may consist entirely of
vertical mill stones with fixed running surfaces and movable runners or with fixed
runners and rotating running surfaces.
Finally, in a further modification of the arrangement, the running surfaces may
form annular grooves for the unweighted balls, which grooves may be of the width
of a ball and deep enough to contain two or more balls therein, one above the
other. The grinding surfaces of the rotating discs may be made of hard cast
metal to the form of a radially multiple cut out ring, so that on a somewhat quicker
rotation these ring sectors are thrown outwards against the balls and exert thereon
the pressure which is necessary for the grinding process. Conical or bevelled rings
may be placed between the discs to cause a better distribution of the material
which is to be ground, which is thus forced to describe a zig-zag course between the
balls. In addition to this, the whole apparatus may be so arranged as to be movable
in the opposite direction to the grinding discs situated on the shaft. In such an
arrangement there are therefore no stationary grinding surfaces. This rotation
may be produced by the apparatus which rests on a pivot at the base having on its
cover a rack, whilst the hollow shaft carries a toothed wheel which coincides with

page_text: the said rack. A cogwheel seated on a driving shaft engages with both so that
on the rotation of this driving shaft and its cogwheel, both rack and toothed wheel
are rotated in opposite directions. In this case the supply of the material to be
round as well as the removal of the finished product and the introduction of the
r current must take place by means of the rotating shaft and this is attained 'as
entioned by making the said shaft which rests on the same pivot, hollow, and
making use of it as an insertion pipe, in the centre of which the tube for carrying
off the dust is placed, and in the centre of this latter is placed the air pipe which
conveys under the lowest grinding stage or tier the current of air produced by a
fan. The joints between these pipes are rendered secure in the same way by
means of mercury as was done for protecting the bearings of the shaft hereinbefore
described.
Dated this 17th day of May 1894.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
improvements in or appertaining to Grinding or Pulverising
Machines.
I, CARL WEGENER of 14 Gitchinerstrasse, Berlin in the Empire of Germany
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 has for its object a system of grinding or pulverising machines,
which system consists in arranging a number of separate mills or grinding appliances
in stages or tiers one over another, in a common casing or frame dust-tight to the
outside, in such a way that the substance to be ground passes through the several
stages from the top to the bottom, a separation and removal of the finished product
being simultaneously effected by a current of air passing from below upwards; that
is to say, in an opposite direction to that of the material which is to be ground.
The removal of the finished product may also take place from the uppermost only
or from any other of the stages. The kind of grinding apparatus employed is
also immaterial, whether they be ordinary disc mill stones, edge running or roller
mill stones, or ball mills, or otherwise consist of a combination of these or other
systems.
In the accompanying drawings:-
Figures 1 and 2 show a series of ball mills arranged one above the other.
The arrangement consists of an upright cylinder, built of rings b bb, which is
closed above and below by a cover a' and a bottom piece a respectively. A vertical
shaft o, driven by a worm wheel and endless screws passes centrally through the
apparatus from top to bottom; and carries a number of dish-shaped discs e corre-
sponding to the number of the rings b. These discs are provided on their outer
periphery with ring-shaped grinding-surfaces e, which latter, in combination with
fixed bevelled rings e³, supported on projections provided on the cylinder rings b
form running surfaces for the balls d. There remains, between the. fixed bevelled'.
rings and the rotating disc-rings e, an annular interstice through which the
more or less finely subdivided material falls on to the next series of balls in order
to be further pulverised. On the rotation of the shaft and consequently of the
discs c, the balls d will necessarily make a rolling movement in the gutter formed
by, the running surfaces, and thereby disintegrate the material which is to be
ground, which then falls between the balls and the running surfaces.

page_text: The material to be ground, delivered through the mill hopper which is provided
with a closing slide or valve, comes first into the topmost stage, and, after
sufficient pulverisation, passes through the interstice i into the next stage, where it
is further pulverised, and so on, until, after leaving the lowest stage, it reaches the
bottom a, and is forwarded by conveyors or scrapers c to the exit k¹, and from 5
thence by the pipe to the elevator ³. This latter again raises the still insufficiently
pulverised material and discharges it through pipe & again on to the uppermost
stage of the mill. It is thus evident that material which has not been ground
cannot leave the mill.
The separation of the sufficiently ground material from the coarser particles, 1
is effected by means of a current of air produced by means of a fan g, which
current of air is conveyed through a pipe gl to the bottom of the apparatus,
that is to say, under the lowest stage. There is thus introduced into the
interior of the apparatus a current of air rising upwards from the bottom,
which is preferably of sufficient strength to convey with it the ready ground
material or finished product through the interstices of the parts of the mill
to the uppermost stage or tier, and from thence through exit pipe e' to the
collecting chamber. The floor of the latter is provided with openings having
rings for spouts to which sacks may be fastened from beneath. These openings
may be provided with covers, which may be opened or closed by means of
levers so that, during the changing of a full sack for an empty one, the collecting
chamber may be closed to the outside. If it be not desired to run the dust or
powder directly into sacks, may be blown through exits hh out of each stage into
a collecting pipe h, and thence to a conveying worm 2, which then conveys it
direct to, the place where it is to be used or stored.
In order that the bearings which are placed in the cover and base for the vertical
shaft c may not be fouled or damaged by the dust, the following arrangement is
employed
11
"
Rings are attached (concentrically to the vertical shaft) to the under side of the
cylinder-cover a and to the under side of the lowest rotating disc c, and these rings
fit loosely into rings m of a U-shaped section arranged on the base a of the cylinder
and on the shaft or the uppermost rotating disc c', and in fact in such a way that
If
the rings fit with their tubular part into the annular groove of the rings m.
these grooves be filled with mercury, a thoroughly dust-tight joint is formed, as it
cannot be affected by the slight wind pressure, and the bearings are thoroughly
protected from the action of the dust which often has a grinding effect, as this dust
is always lighter than the mercury in consequence of the greater specific gravity of
the latter and thus cannot pass through the mercury to reach the inner side of the
rings l.
Other forms of construction of the apparatus hereinbefore described are shown in
Figures 3 to 10.
Figures 3 and 4 show an arrangement in which the balls travel on slightly
conical downwardly inclined surfaces, and further are loaded by grinding-discs c³,
which rotate with the main shaft c but which have a free vertical adjustment
thereon.
The top or back of these weighting discs must of course be of such a shape that
the material which is to be ground slips off it downwards and is thus conveyed to
the next stage or tier. The fixed conical surfaces c³, which rest on annular
projections c, must in this case have so large a central hole that there remains
between them and the shaft sufficient room to allow of the material to be ground
falling through. On the top or back of the rotating grinding discs cl the material
again reaches the outer wall of the cylinder, and falls into the annular interstice
which is enclosed by these discs and the cylinder, and on to the next grinding
surface.
Figure 5 shows a combination of this arrangement with edge running or roller
mill stones, which may be. either attached to the rotating grinding discs, as shown
in the upper part of the figure, so that they grind on fixed grinding surfaces whilst

page_text: their side surfaces run on balls, or they may, as shown in the lower part of the
figure, be held in a fixed support so that they travel on rotating grinding surfaces
whilst again their side surfaces travel on balls.
In Figure 5, the axles of the edge running or roller mill stones are shown
inclined an arrangement is shown in Figures 6 and 7 in which these axles stand
vertically on the rotating surfaces on which the balls run, on which latter the side
faces of the mill stones travel, whilst the peripheral surfaces grind on the inner
surfaces of the rings 6 of the casing.
Figure 8 shows a form of construction in which the mill arrangement consists
entirely of edge running or roller mill stones, with fixed grinding surfaces and
travelling edge runners (see the upper part of the figure), or with fixed edge
runners and rotating grinding surfaces (see the lower part of the figure).
Finally, Figures 9 and 10 show a further modification of the arrangement in
which the running surfaces form annular grooves for the unweighted balls, which
grooves may be of the width of a ball and are deep enough to contain two or more
series of balls therein one above the other. The grinding surfaces of the rotating
discs may be made of hard cast metal, to the form of a radially multiple cut out
ring, so that, on a somewhat quicker rotation, these ring sectors are thrown
outwards against the balls and exert thereon the pressure which is necessary for
the grinding process. Conical or bevelled rings may be placed between the
discs to cause a better distribution of the material which is to be ground, which is
thus forced to describe a zig-zag course between the balls. In addition to this, the
whole apparatus may be so arranged as to be rotatable in the opposite direction to
the grinding discs o situated on the shaft. In this arrangement there are therefore
no stationary grinding surfaces. This is attained by the apparatus, which rests on
a pivot s at its base, having on its cover a rack or crown teeth z, whilst the hollow
shaft w carries a toothed wheel of the same gear as the rack z. A wheel ²,
cog
seated on the driving shaft r, engages with both, so that, on the rotation of this
shaft and its cog wheel z, both rack z and toothed wheels are rotated in opposite
directions. In this case, the supply of the material to be ground as well as the
removal of the finished product and the introduction of the air current, inust take
place by means of the rotating shaft, and this is attained, as mentioned, by making
the said shaft, which rests on the same pivot s, hollow, and making use of it as an
insertion pipe, in the centre of which the tube for carrying off the dust is placed,
and in the centre of this latter is placed the air pipe g', which conveys, under the
lowest grinding stage or tier, the current of air produced by a fan. The joints
between these pipes are rendered secure against the dust in the same way by means
of mercury as was done for protecting the bearings of the shaft e hereinbefore
described.
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 :-
1. An improved grinding or pulverising machine consisting of a series of grinding
appliances in a common casing or frame closed dust-tight to the outside, operated
by means of a common vertical central shaft, and so arranged in stages or tiers one
above the other that the material which is to be ground is conveyed first to the
uppermost tier and then passes successively through those lying beneath it, whilst
the finished pulverised material is separated from the material which is to be ground
by means of a current of air flowing through the apparatus from the bottom
upwards, and is blown out or discharged from the uppermost or any desired tier,
the separate grinding appliances each consisting of one stationary and one rotating
bevel disc between which discs balls travel under pressure of the upper disc, the
upper bevelled surfaces of the stationary and rotating discs having such an inclina-
tion that the material travels slowly down them towards the bottom, substantially
as described and illustrated.
2. A grinding or pulverising machine of the kind described in Claim 1,

page_text: characterised by the insufficiently pulverised material from the lowest tier being
again re-conveyed to the upper tier by means of an elevator, substantially as
described and illustrated.
Dated this 15th day of February 1895.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.