Cooling the Rolls and Meal in such Mills.
Year: 1885

page_text: Cooling the Rolls and Meal in such Mills.
I, LOUIS RAPPAPORT, of 13 Friedrich-Wilhelmstrasse, Breslau, Prussia, Inventor,
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:—
The foregoing invention relates to a process for cooling, by means of air, the
rolls of a roller mill from inside as well as from outside, with the simultaneous
cooling of the meal.
The process hitherto generally employed for cooling the meal and rolls in roller
mills cousists in introducing air by means of an exhauster, into the casing enclosing.
the rolls, which air playing against the rolls and amongst the meal, cooled, from
without, the latter. This air was subsequently passed through an agitated filter,
stretched with a textile and situated outside the casing containing the rolls which
filter retained the particles of meal. The cooling of the rolls by this process is
only an incomplete one, since the air does not impinge directly against the rolls
which are covered with meal, and the temperature in the casing rises also con-
siderably. The use of a strong exhaust current is precluded, for in such case the
entire body of meal would be drawn outwards to the filters.
It has also been proposed to pass water through the hollow axes of the rolls into
the interior of the same, and subsequently to carry away such water again through
the hollow axes; a simultaneous cooling of the rolls and of the meal is not
however, by this process, obtained, the danger is also incurred that the water may
come in contact with the meal, for want of watertight packing, thus spoiling the
meal.
The present process differs from both of the foregoing in that the air is drawn
by means of an exhauster, from the open front of the rolls into their hollow
interior, and is led from here, through special channels, into the lower portion of
the casing enclosing the rolls in order to be passed through a revolving filter in the
casing itself or in close connection with it. To perfect the operation the filter may
be continuously brushed or knocked.

page_text: By means of this process the rolls by being cooled from the inside prevent the
heating of the meal, and, by the direct effect of the air on the outside, prevent the
beating of both the rolls and meal.
The accompanying drawing shows a roller mill provided with the cooling
appliance; Figure 1 being a cross section, and Figure a longitudinal one.
The rolls bb are hollow cylinders, which contain in their front sides a number of
holes c.
The front ends a a of the rolls run in rings e, which are fastened to the
case d, and the rolls are in this manner separated from the interior of the casing.
The air, which is introduced at c by means of an exhauster, passes through the
interior of the rolls and makes its exit at c¹ carrying along with it, in the direction.
of the axis, the meal through the passage f inside the casing d to the revolving
filter and exit shoot h. The filter 9 which is situated upon shaft and consists
of a disc stretched with textile material or metallic gauze, is being continuously
cleansed from adhering particles by means of the stationary brush i, which is placed
inside a casing k to which the air cannot have access. The shaft of the filter is
set in motion by means of the pulley m from the axis n of the rolls. The filter
may however also be cleaned by the aid of a knocker or rapper p inside the casing,
which is elevated by means of a piece q on the filter disc at each revolution and
subsequently falls on the filter thereby beating it.
Figure 2 shows a roll provided with an archimedean screw thus causing the air
to play against the walls with the best possible effect.
Immediately the exhauster is set at work it draws the air along the course
indicated by the arrows, namely, through the hollow rolls b and shoots finto the
lower portion of the casing, and from here through the rotary filter g and out by
the shoot h. There will consequently be a steady current of air circulating through
the rolls, which will thus be cooled down to the lowest temperature. For many
purposes it will be found advantageous to previously cool down the air to a low
temperature. I attain this by leading the air to be used through earthen channels.
By this arrangement the rolls themselves, and indirectly the meal, will be cooled
from within, and the meal itself from without.
By this process the temperature will be lowered, in the course of a lengthy
treatment, to twenty degrees or less.
Should a special cooling of the meal not be necessary and a moderate cooling
have already been effected by means of the cooled rolls, the exhauster can be
connected direct to the shoot fand exhaust through the shoot o; the air in such
case will not enter at all into the space in the casing for the meal. By this
arrangement the axles with their bearings will also be kept cool whilst not only
an indirect cooling takes place by means of the current of air, but the heating of
the axles and bearings, owing to the otherwise high temperature of the rolls will
be hindered. In this manner smooth metal rolls may successfully be kept so cool
that they work like porcelain rolls and consequently the meal, which passes through
the rolls will no longer be discoloured. As will be seen from the entire construction
a powerful blast may be used in place of an exhauster. Further the apparatus may
be so arranged that the air, instead of entering through holes in front of the rolls,
may be drawn through a hollow axis, which is suitably perforated.
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. In roller mills the process of driving air in a cooled or otherwise condition,
through the hollow portion of the revolving rolls, whose front sides are open, in
order to protect the rolls axles and bearing against immoderate heating.
2. Guiding the air through hollow rolls, which in consequence of the arrangement
of ribs on the interior periphery of the rolls, compel the air to take a spiral course,
as shown on the drawing.

page_text: 3. In combination with the process described in claim 1, leading the air, which
has entered through the hollow portion of the rolls, into the meal casings, so that
thereby the meal will be simultaneously cooled.
4. In roller mills, the process for producing by means of an exhauster or blast
an uninterrupted suction to effect the cooling of the rolls and meal.
5. In roller mills, the combination of hollow rolls b, either with channels f. h
exhauster in channel h and filter g, or with channels f, o, and an exhauster working
in the channel o, or in place of the exhausters the application of a blast.
6. The application of a rotary filter, in a meal chest, with a brush or knocker or
rapper.
7. Cooling the air by conducting it through earthen channels.
Dated this 25th day of November 1885.
WP. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, and
323, High Holborn, London,
Patent Agents for the Applicant.