Improvements in Mills for Pulverizing or Pulverizing and Mixing.
Year: 1899

page_text: Date of Application, 30th Mar., 1899
Complete Specification Left, 14th Dec., 1899-Accepted, 27th Jan., 1900
PROVISIONAL SPECIFICATION.
Improvements in Mills for Pulverizing or Pulverizing and Mixing.
I, MEYER JOSEPH DAVIDSEN, of 29, Vestergade, Copenhagen, in the Kingdom
of Denmark, Engineer, do hereby declare the nature of this invention to be as
follows:-
In the Specification of a former Patent granted to mo No. 21708 dated
14 November 1893 there are described mills comprising approximately horizontal
tubular chambers adapted to be rotated about their axes and provided with loose
balls, the materials to be treated being fed into each chamber at or about tho
ventral portion of one end and the treated material being discharged at the peri-
phery of the chamber near its other end. An object of the present invention is
to render mills of such a type more suitable for treating comparatively soft
materials such as the raw materials from which cements are made, Roman cement,
coal, coke or the like.
For this purpose the end walls of the tubular chamber are each formed with a
centrally arranged inlet aperture and the chamber is formed with peripheral dis-
charge apertures located at a distance from each end wall, the arrangement being
such that the material during treatment can pass in opposite directions from the
respective ends of the chamber to the discharge apertures.
In one arrangement the end walls are provided with hollow trunnions which
are mounted in suitable bearings and through each of which the material in the
form of pieces, lumps or coarse meal is fed, for instance, by means of a screw
conveyor working therein and supplied with material from a hopper. The
chamber is provided, preferably near one end, with a toothed wheel adapted to gear
with a train of suitably driven wheels.
The chamber is formed with peripheral discharge apertures, which may be
longitudinal slits at the middle of its length and is half filled with balls.
The
The material fed in, first becomes heaped up at the ends of the chamber, then
slowly sinks down between the grinding balls towards the middle of the chamber,
and then falls out through the discharge apertures in the form of powder.
length of the grinding chamber is in this way utilized to great advantage and the
chamber can be easily rotated because, as both trunnions serve for the introduction
of the material, it is not necessary to give them any great diameter in order to
enable material to be fed into the mill in great quantity.
If it is desired to grind material of different degrees of hardness in the ball-
mill at the same time, the discharge apertures are arranged nearer to one end.
than to the other that is to say, nearer to the end at which the softer material
is to be introduced so that the lengths of the paths traversed by the two materials
to be treated is proportional to their capability of being ground. The ground
materials would in this case become mixed as they are discharged but if this
should not be desired, the chamber may be divided into two parts by a partition,
the chamber being formed at each side thereof, with peripheral discharge aper-

page_text: tures or slits. In this case, again, the partition and the discharge apertures may
be arranged either in the middle of the mill, or, nearer to one end for the pur-
pose hereinbefore mentioned.
The discharge apertures may be surrounded by an annular collecting chamber
provided with one or more delivery shoots; in the case of a divided grinding
chamber the collecting chamber may be divided by an annular partition so
arranged that the material from one end of the chamber is collected on one side
thereof and that from the other end upon the other side, separate shoots leading
from each portion of the collecting chamber.
i
Improvements in Mills for Pulverizing or Pulverizing and Mixing.
I, MEYER JOSEPH DAVIDSEN, of 29, Vestergade, Copenhagen, in the Kingdom
of Denmark, Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
In the Specification of a former Patent granted to me No. 21708 dated
14 November 1893 there are described mills comprising approximately horizontal
tubular chambers adapted to be rotated about their axes and provided with loose
balls, the materials to be treated being fed into each chamber at or about the
central portion of one end and the treated material being discharged at the peri-
phery of the chamber near its other end. An object of the present invention is
to render mills of such a type more suitable for treating comparatively soft
materials such as the raw materials from which cements are made, Roman.cement,
coal, coke or the like.
For this purpose the end walls of the tubular chamber are each formed: with a
centrally arranged inlet aperture and the chamber is formed with peripheral dis-
charge apertures located at a distance from each end wall, the arrangement being
such that the material during treatment can pass in opposite directions from the
respective ends of the chamber to the discharge apertures.
Referring to the accompanying drawings
Fig. 1 is a longitudinal section of the tubular chamber of one arrangement of
mill according to the present invention;
Fig. 2 is a similar view of a slightly modified arrangement and
Fig. 3 is a sectional elevation of a modified form of mill.
a is the tubular chamber, the end walls of which are provided with hollow
trunnions 6 which are mounted in suitable bearings 6 and through each of which
the material in the form of pieces; lumps or coarse meal is fed. The chamber is
provided, preferably near one end, with a toothed wheel c adapted to gear with a
train of suitably driven wheels. The chamber is formed with peripheral dis-
charge apertures d, which may be longitudinal slits as shown in Figs. 1 and 2;
the chamber is half filled with balls (not shown) as described in the specification
of my previous patent above referred to.
The material fed in, first becomes heaped up at the two ends of the chamber,
then slowly sinks down between the grinding balls towards the middle of the
chamber and then falls out through the discharge apertures in the form of

page_text: powder. The length of the grinding chamber a is in this way utilized to great
advantage and the chamber can be easily rotated because, as both trunnions b
serve for the introduction of the material, it is not necessary to give them any
great diameter in order to enable material to be fed into the mill in great
quantity.
The slits d may be arranged at the middle of the length of the chamber but if
it is desired to grind material of different degrees of hardness in the ball-mill at
the same time, the discharge apertures are arranged nearer to one end than to
the other that is to say, nearer to the end at which the softer material is to be
introduced so that the lengths of the paths traversed by the two materials to be
treated is proportional to their capability of being ground. In the arrangement
shown in Fig. 1, the slits d are at the middle of the length of the chamber a, and
in that shown in Fig. 2 they are nearer the right hand end.
In the arrangements shown in Figs. 1 and 2 the ground materials would become
mixed as they are discharged through the slits d, but, if this should not be desired,
the chamber may as shown in Fig. 3 be divided into two parts by a partition e,
the chamber being formed at each side thereof, with peripheral discharge aper-
tures or slits d. In this case, again, the partition and the discharge apertures
may be arranged either in the middle of the mill, or, nearer to one end for the
purpose hereinbefore mentioned. The discharge apertures may be surrounded by
an annular collecting chamber provided with one or more delivery shoots. In
the case of a divided grinding chamber as shown in Fig. 3 the collecting
chamber may be divided by an annular partition f* so arranged that the material
from one end of the chamber is collected on one side thereof and that from the
other end upon the other side, separate shoots g and h leading from each portion
of the collecting chamber. The shoots 9 and h may if desired discharge into a
mixing machine or the materials may be separately collected in bags or otherwise,
for subsequent mixing or use as required.
As shown in Fig. 3 the chamber a communicates through its trunnions with
hoppers k, the material being fed through each trunnion by means of a screw
conveyor m.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. A mill for pulverizing or pulverizing and mixing of the kind described in
the specification of my previous patent herein before referred to wherein the
materials to be treated are introduced at both ends of the cylindrical grinding
chamber and will travel during treatment in opposite directions from the respec-
tive ends of the said chamber, and, when treated, will be discharged through peri-
pheral discharge apertures so located that the lengths of the paths traversed by
the materials is proportional to their capability of being ground, substantially
as described.
2. Mills of the kind described in the specifiication of my previous patent here-
inbefore referred to, constructed arranged and operating substantially as respec-
tively described with reference to and shown in Fig. 1, Fig. 2, and Fig. 3 of the
accompanying drawings.
Dated this 14th day of December 1899.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.