Improvements in Centrifugal Roller Mills, principally for Crushing Quartz.
Year: 1898

page_text: Date of Application, 26th Sept.; 1898-Accepted, 29th Oct.. 1898
COMPLETE SPECIFICATION.
Improvements in Centrifugal Roller Mills, principally for Crushing
Quartz.
I, WALTER PALMER WYNNE, of Nos. 33 to 47, Armstrong Street, Ballarat, in the
Colony of Victoria, Manager, 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 stateinent:-
This invention relates to centrifugal roller mills and particularly such as are
commonly used instead of stamper batteries for crushing quartz.
Its object is to remedy certain defects which have been discovered in the
practical working of these mills, and which materially impair their efficiency.
These defects consist; first,-in the material under treatment being carried around
within the pan at about the same rate as the rolls the consequence of which is that
large proportion of such material remains in front of the said rolls and is not acted
on by them, and secondly, in the screen through which the finely ground material
passes being injured and quickly worn out by reason of the larger pieces of
inaterial being constantly thrown against it.
My improvements consist first in making the pan rotate in an opposite direction
to that of the main or central spindle, and secondly in providing an inner and
coarser screen within the ordinary one.
The manner in which my invention can be carried out in practice will be readily
understood from the following description with reference to the accompanying
drawing which is a vertical central section of a centrifugal roller mill embodying my
improvements.
According to my invention I make the circular pan A, of the mill to revolve,
for which purpose it is constructed with a central cone A¹, fitting around a central
spindle B carrying at its upper end arms B', from which depend the shafts C of the
centrifugal crushing rolls D. These latter are fitted with anti-friction balls d as
shewn in order to reduce their wear and tear and reduce the driving power
required.
The under-side of the pan A, is provided with a toothed wheel E into which gears
a pinion E¹, upon a shaft E2, gearing through spur wheels E³, with the main
driving shaft F, which is provided with a pulley or pulleys F1, and is fitted with a
bevel pinion F2 gearing with another bevel pinion Fs on the lower end of the
spindle B driving the centrifugal rolls D which are mounted on the depending
shafts C.
The under-side of the pan A is provided with an annular track, or way G
resting upon antifriction wheels G¹, whereby it is supported and yet allowed to
rotate freely.
Of
H H¹ represent two screens which are arranged practically all round the pan A
a short distance above the steel ring die D¹ against which the rolls D run.
these two screens the inner one H is coarse and made of stout material, whilst the
outer one H¹ is of finer mesh and determines the degree of fineness to which the

page_text: material must be crushed before being delivered from the machine. The inner
screen serves as a shield for the outer one and prevents the larger material-which
is swirled around within the pan-from wearing away the finer material of which
the outer screen is composed.
The material discharged through the screens is delivered into an annular or
other discharge trough, or launder I, and can be carried away to the tables or other
desired place of discharge.
It will be obvious that with the gearing above described the pan A will be
rotated in the opposite direction to the main central spindle B consequently the
material within the pan will be held back owing to the slow backward travel of
said pan so that the rolls will as it were overtake the material. In other words
the tendency to form a whirlpool within the pan will be counteracted.
This is a great advantage as will be readily understood by persons experienced
in the working of this class of milling machinery, as it allows the work to proceed
more evenly and with better results.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I claim
is
1. In a centrifugal roller mill the combination with crushing rolls mounted on
depending shafts carried from a main or central spindle of a pan and means for
rotating the said main or central spindle and pan in opposite directions substantially
as and for the purposes herein before described and illustrated in the accompanying
drawing.
2. In a centrifugal roller mill a circular pan fitted with an inner coarse screen
and an outer fine screen substantially as and for the purposes herein before described
and illustrated in the accompanying drawing.
Dated this Nineteenth day of August One thousand eight hundred and
ninety-eight.