Improvements in Ball Grinding Mills.
Year: 1899

page_text: Magdeburg-Buckau, in the Empire of Germany, Manufacturers.)
Improvements in Ball Grinding Mills.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 improvements in ball grinding mills which may be employed
for reducing many substances but which are more especially applicable to the grinding,
in a wet condition of ores which are obtained in a moist state and are treated by a wet
process.
Attempts to grind such ores in a wet condition, in which the water has either been
admitted to the machine through the inlet for the introduction of the substance to be
ground or has been sprayed by nozzles against the outer sieve, have not hitherto led'
to any satisfactory result because during such process the spaces between the grinding,
plates and the first or coarse sieves and also between the latter and the fine sieves usually
become clogged or choked with mud.
According to this invention, this clogging or choking with mud is obviated by
partially immersing the ball mill to a predetermined depth in water in a trough or
vessel and keeping the water and 'material within the mill in motion:.
In order that my invention may be clearly understood and readily carried into effect
I will now proceed to describe the same more fully with reference to the accompanying
drawings in which
Figure 1 is a vertical transverse section and Figure 2 a vertical longitudinal section
of a ball mill constructed according to this invention.
1 is the hopper and 2 is the hub provided with apertures by which the material is
fed to the mill. The material is ground or reduced by means of the balls acting in
co-operation with the grinding plates 4, as the mill rotates about the central axis 3.
5 is the coarse sieve and 6 is the fine sieve. 7, 7 are return plates for conducting the
coarser particles from between the plates 4 and the sieve 5, and also from the space
between the sieves 5 and 6, back to the interior of the mill for further reduction. 9 is
the mill casing the lower part 8 of which is preferably tapered and forms a trough
10 is
which is kept filled with water and through which the water constantly flows.
a pipe by which water enters at the bottom of the trough 8, and 11 are nozzles which
deliver water upon the upper part of the mill as it rotates. 12 is an adjustable slide by
which the water level in the trough is determined, the water being maintained at such a
level in the trough 8 that the mill is immersed and rotates therein at a depth approxi-
mately corresponding to the point at which the coarse sieve is situated. 13 is a pipe for
conducting away the coarser particles from the bottom of the trough 8 to the channel 14
whence they may be conveyed to any suitable vessel for further treatment.
pipe 13 may either be fixed or (as shown in the drawings) it may be telescopic so
that by regulating the height of the outlet the fineness of the particles conducted
away may be determined.
This

page_text: The water may be admitted either through the nozzles 11 and the pipe 10 or
through either of these, according to the nature of the material to be treated.
The
As the mill revolves the ground material falls through the holes in the grinding
plates 4 upon the coarse sieve 5 and through this latter upon the fine sieve 6.
material that is sufficiently finely ground passes through the sieve 6 into the
trough 8 and the coarser particles which cannot pass through the sieves are returned
by the plates 7 to the interior of the mill to be further reduced. The vigorous
circulation of water which is maintained greatly assists in the process of reduction,
as it washes the fine particles out of the substance which is being ground. The fine
mud is kept in suspension at the upper portion of the water trough 8 and flows over
the slide 12 with the water. The grit and coarser particles sink to the bottom of
the trough 8 and owing to the pressure of the water above them are conducted
through the pipe 13 into the channel 14. The principal object of the nozzles 11 is
to afford special means of swelling the outer sieves when necessary. The water is
admitted through the pipe 10 principally when the substance to be ground contains
very fine dust which it is desired to separate from the heavy grit and the like by
means of the ascending current of water.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, as communicated to me by my
foreign correspondents, I declare that what I claim is :-
1. A ball grinding mill partially immersed in a trough in which water is caused to
circulate substantially as described, for the purpose specified.
2. A ball grinding mill such as that referred to in Claim 1, partially immersed in
water in a trough provided with means for varying the water level and with admission
and discharge pipes and spraying nozzles all substantially as described for the
purposes specified.
...
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3. The apparatus constructed, arranged and operating substantially as described
with reference to the accompanying drawings for the purpose specified.
Dated this 29th day of March 1899.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.