Improvements in or relating, to Centrifugal Disintegrating and Mixing Mills or Apparatus suitable for use in the Manufac ture or Treatment of Paper Pulp.
Year: 1894

page_text: Date of Application, 28th May, 1894
Complete Specification Left, 23rd Feb., 1895 Accepted, 27th Apr., 1895.
PROVISIONAL SPECIFICATION.
Improvements in or relating, to Centrifugal Disintegrating and
Mixing Mills or Apparatus suitable for use in the Manufac
ture or Treatment of Paper Pulp.
We, Dr. OTTO ZIMMERMANN, of 4 An der, Leimfabrik, Ludwigshafen a/ Rh.,
Germany, Manufacturer, and GUSTAV HAGEMANN, of 13 Moltkestrasse,
Ludwigshafen af Rh., Germany, Engineer, do hereby declare the nature of this
invention to be, as follows:-
This invention relates to a wet centrifugal mill with circulation-vessel for
separating or disintegrating cellular substance and for mixing paper pulp, in which
such working parts of apparatus heretofore employed for the purpose, as, knife-
rollers, and pin-rollers with corresponding opposing parts, ball mills &c., are
replaced by a wet working centrifugal mill, "dismemberer or disintegrator,
through which the material to be treated is passed again and again until the
requisite degree of uniformity has been reached.
"
Cellular substance is disintegrated, by this apparatus very energetically and very
rapidly; the elementary fibres are completely separated from one another, without
being cut up, crushed or otherwise damaged; these properties not being possessed in
such a high degree by any apparatus heretofore usually employed for disintegrating
cellular substance.
Our wet centrifugal mill will also compare favorably with other apparatus as a
mixing device. It is especially suitable for mixing together different kinds of
paper pulp, and also for mixing paper pulp with size, earths, colors, &c.
The use of the wet centrifugal mill for the aforesaid purpose allows of a great
number of different arrangements of the apparatus determined partly by the desired
result, and partly by local circumstances, and also of a great number of ways of
combining the same with the circulation-vessels which may be constructed in a
great variety of shapes.
All kinds of pulp-engine troughs may be employed as circulation-vessels.
Vertical vessels might also be employed, in which case the circulation of the pulp
would take place more in a vertical sense. But in all cases the arrangement
of the centrifugal mill must allow of the circulation as perfect as possible of
the pulp.
We shall however only proceed to describe the most suitable arrangement in our
opinion of a wet centrifugal mill which comprises a rotating pin-disc and
stationary ring of pins, and a peculiar mode of water supply.
&
In this construction the mill is mounted over a vertical cylindrical tube the upper
edge or end of which is arranged to form an annular closed box the cover of which
constitutes at the same time the fixed ring of pins of the mill. A vertical shaft
passing through the said tube carries the upper rotating pin disc, and is co-axial
with the tube. It passes through the bottom of the circulation-vessel by means of
a stuffing box and is driven from below. If it be desired however to dispense with.
the stuffing box, the shaft may be driven from above, and in such case a footstep
bearing is by preference provided on the bottom of the circulation-vessel.
The pins of the fixed ring are each provided with an axial perforation which
extends almost up to the point of the pin and is in communication with the annular:
The latter communicates by a pipe with the water main from which the
box.

page_text: water passes under pressure into the perforations of the pins of the fixed ring..
From these perforations the water spirts through small holes distributed over the
entire length of the pins, out against the pins of the revolving disc.
The pins may however be provided with an axial perforation only passing
entirely through the pin, so that the water can only pass out at the tops of the
pins. In such case, the water spirts first against the revolving disc by which it is
thrown against the pins of that disc by which it is broken up into spray.
In order to prevent the water from flowing along the surface of the revolving
disc directly outwards, it is of advantage to cut grooves or hollow mouldings in the
rotary disc above the rings of pins of the fixed disc, that is to say, above the point.
of exit of the water, so that the water may by this means be with certainty
deflected downwards and caused to pass between the pins.
When the speed of revolution is sufficiently great, the pins will break up the
water into spray and will project it with great force in a tangential direction, the
water producing a suction action similar to that of the well-known spraying nozzles.
It follows from this that the pulp which stands in the tube at a level only slightly
below the upper edge of the tube is sucked up and led into the mill to be
disintegrated or mixed by the latter. The pulp which is thrown out by the mill
with great force, may advantageously be caused to impinge against a concentric
wall so as thereby to undergo a further disintegrating action.
The pulp then flows from this wall direct or through a channel or conduit into
a suitable vessel which communicates with the lower end of the tube. In this
manner a circulation is produced which enables the pulp to be passed through
the mill as often as necessary to effect the desired degree of uniformity or
homogeneity.
If the pulp is to be washed at the same time, and this is generally desirable in
the disintegration of cellular substance, the pulp circulating vessel is preferably
made in the form of a pulp-engine trough in which then the washing cylinders are
arranged in the well known manner. In the washing operation, the water may b
allowed to flow continuously through the lower pins of the mill. But if it b
only desired to disintegrate or mix the material, water is allowed to flow through
the pins only until the pulp has been sucked up, whereupon the water supply
is cut off.
Although to effect a proper mixing it is of great advantage to introduce the
water through the pius of the mill it is not absolutely necessary but it can be
introduced at any suitable point of the circulation-vessel. In such a case however
it is necessary to lift the pulp. by means of a device of some kind up to the mill,
because the mill will not suck without water supply. This lifting of the pulp may
be effected in a simple manner by means of screws, turbines &c. mounted on the
shaft of the mill.
It is preferable to arrange the mill in the centre of a double pulp-engine trough
because this plan enables an excellent circulation to be obtained, as in it there
are no "dead corners " which might give rise to accumulations or deposits of pulp.
The pulp-engine trough and the casing of the mill may be constructed of
cement-concrete, or on the Monier system, so that merely the working parts
valves &c. need be made of metal.
It is obvious however that the circulation-vessel and casing may be made of
metal or wood. The arrangement is readily accessible in all its parts and is
of very simple and strong construction. The operation of the apparatus is as
follows:-
The circulation-vessel being sufficiently charged with pulp, and the mill being
started, a valve is opened to allow water to flow from the main into the annular
box and from the latter into the pins. From these the water spirts out through the
bereinbefore mentioned small holes against the pins of the rotating disc which break
up the water into spray and throw it off. The pulp sucked up by this action rises
up in the tube, passes through the mill and is thrown against the wall of the
annular channel on the bottom of which a number of saddle-pieces (say four) are

page_text: formed for the purpose of distributing the pulp uniformly. From the annular
channel the pulp flows through four openings into the outer compartments of the
three-part pulp-engine troughs thence flowing along the circulation-vessels and
through the tube until it again enters the mill. In this manner the pulp can be
made to pass through the mill as often as desired.
-
In place of the fixed ring of pins, a rotary pin-disc may be employed, and the
mill thus be converted into a disintegrator. In this case the driving power may
be applied from both ends. The lower pin disc is then open-worked at its centre
to correspond to the cross sectional area of the tube, and the spokes thus formed
are advantageously made as screw vanes.
These screw vanes may also be developed to form a complete screw which dips
into the pulp to be lifted, and, when provided with a surrounding casing or envelope,
serves to supply the pulp to the mill.
Improvements in or relating to Centrifugal Disintegrating and
Mixing Mills or Apparatus suitable for Use in the Manufacture
or Treatment of Paper Pulp.
We, Dr. OTTO ZIMMERMANN, of 4 An der Leimfabrik, Ludwigshafen a/ Rh.,
Germany, Manufacturer, and GUSTAV HAGEMANN, of 13 Moltkestrasse, Ludwig-
shafen a Rh., 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 relates to a wet centrifugal mill, with circulation-vessel, for
separating or disintegrating cellular substance and mixing paper pulp. In our
apparatus such working parts as knife-rollers, pin-rollers with corresponding
opposing parts, ball mills &c. with which apparatus heretofore employed for the
purpose have been provided, are replaced by a wet working centrifugal mill,
dismemberer or disintegrator, through which the material to be treated is repeatedly
passed until the requisite degree of uniforinity has been reached.
Cellular substance is disintegrated by this apparatus very rapidly and
energetically and the elementary fibres are completely separated from one
another, without being cut up, crushed or otherwise damaged. The apparatus
compares very favorably in this respect with the apparatus heretofore usually
employed for disintegrating cellular substance and it is also very efficient as a
mixing device being especially suitable for mixing together different kinds of paper
pulp, and for mixing paper pulp with size, earths, colors &c.
The construction and arrangement of the wet centrifugal mill may be varied
within wide limits according to the desired result, and to the particular local
circumstances, and it may be combined in many ways with the circulation-vessels.
These also may be constructed in a great variety of shapes; for instance all kinds
of pulp-engine troughs may be employed as such circulation-vessels; vertical
vessels may also be employed, the circulation of the pulp then taking place more
in a vertical sense than is the case with the arrangement hereinafter more
particularly described. But in all cases the arrangement of the centrifugal mill
must allow of as perfect a circulation of the pulp as possible. We will proceed to
describe by the aid of the accompanying drawings what we consider the most
suitable arrangement of wet centrifugal mill according to our invention and which

page_text: comprises a rotating pin-disc and a stationary ring or rings of pins, and a peculiar
mode of water supply.
Fig. 1 is a plan of the apparatus partly in horizontal section.
Fig. 2 is a longitudinal vertical section on the line A-B of Fig. 1.
Fig. 3 is a section on the line E-F of Fig. 1, and
Fig. 4 is a cross section on the line C-D of Fig. 1.
As shown the mill is mounted over a vertical cylindrical tube 9 the upper edge
or end of which is arranged to form an annular closed box c the cover of which
also constitutes the fixed rings of pins of the mill. A vertical driving shaft
co-axial with the tube g carries the upper rotary pin disc f. It passes through a
stuffing box m at the bottom of the circulation-vessel and is driven from below the
said vessel. If however, it be desired to dispense with the stuffing box m, the
shaft may be driven from above, and in this case a footstep bearing is by preference
provided on the bottom of the circulation-vessel.
The pins d of the fixed ring are each formed with an axial perforation which
extends almost to the upper end of the pin and is in communication with the annular
box c.
The latter communicates by a pipe b with the water main from which the
water passes under pressure into the perforations of the pins d. From these
perforations the water spirts through small holes distributed over the entire length
of the pins, out against the pins e of the revolving disc f.
The pins d may if desired be each provided with an axial perforation only, so
that the water can only pass out at the tops of the pins. In such a case, the water
first issues against the revolving disc f by which it is thrown against the pins e of
that disc and is by them broken up into spray.
To prevent the water from flowing along the under surface of the disc f directly
outwards, it is advantageous to form grooves or hollow mouldings in the underside
of the rotary disc fabove the rings of pins d of the fixed disc, that is to say,
above the point of exit of the water, so that the water may be with certainty
deflected downwards and caused to pass between the pins.
When the speed of revolution is sufficiently great, the pins will break up the
water into spray and will project it with great force in a tangential direction, the
water producing a suction action similar to that of the well-known spraying
nozzles. Consequently the pulp which stands in the tube g at a level only slightly
below the upper edge of the tube will be sucked up into the mill to be thereby
disintegrated or mixed. The pulp which is thrown out by the mill with great
force inay with advantage be caused to impinge against a concentric wall
thus undergo a further disintegrating action. The pulp then flows from this wall
through channels or conduits k into a suitable vessel V which communicates with
the lower end of the tube g as shown. In this manner a circulation is produced
which enables the pulp to be passed through the mill as often as is necessary to
effect the desired degree of uniformity or homogeneity.
and
If the pulp is to be washed at the same time, which is generally desirable in the
disintegration of cellular substance, the pulp-circulating vessel is preferably made
in the form of a pulp-engine trough in which the washing cylinders are arranged
in a well known manner, and the water is allowed to flow continuously through the
lower pins d of the mill. But if it be only desired to disintegrate or mix the
material, water is permitted to flow through the said pins only until all the pulp
has been sucked up once, whereupon the water supply is cut off.
Although to effect a proper mixing it is of great advantage to introduce the
water through the pins d of the centrifugal mill, this is not absolutely necessary as
it can be introduced at any suitable point of the circulation-vessel.
In such a case
however it is necessary to lift the pulp up to the mill by means of a device of
some kind because the mill will not suck it up without a water supply. This
lifting of the pulp can be easily effected by means of screws, turbines or the like
mounted on the shaft of the mill.
It is preferable to arrange the mill, as shewn, in the centre of a double pulp-
engine trough or circulation-vessel V. V because this plan enables an excellent

page_text: circulation to be obtained, as there are no
to accumulations or deposits of pulp.
"
"dead corners which might give rise
The pulp-engine trough and the casing of the mill are shown constructed of
cement-concrete, or on the Monier system, so that only the valves and other
working parts need be of metal, but as will be obvious the circulation-vessel and
casing may if preferred be made of metal or wood. The arrangement is readily
accessible in all its parts and is of very simple and strong construction. The
operation of the apparatus is as follows:-
The circulation-vessel V V is sufficiently charged with pulp, and the mill is
started, whereupon a valve a is opened to allow water to flow through the main b
into the annular box c and from the latter into the pius d. From these the water
spirts out through the herein before mentioned small holes against the pins of the
rotating disc f which break up the water into spray and throw it off outwardly.
The pulp sucked up by this action rises up in the tube g, passes through the mill
and is thrown against the wall g¹ of the annular channel h on the bottom of which
a number of saddle-pieces i (say four) are formed for the purpose of distributing
the pulp uniformly. From the channel the pulp flows through four openings k
into the outer compartments of the engine-troughs. The arrows indicate the
further progress of the pulp until it again enters the mill. In this manner the
pulp can be made to pass through the mill as often as desired.
In place of the fixed ring of pins d, a rotary pin-disc may be employed, and the
mill thus be converted into a disintegrator; in this case the driving power may be
applied from both ends. The lower pin disc is then open-worked at its centre to
correspond to the cross sectional area of the tube g, and the spokes thus formed
may advantageously be made as screw vanes, which may if desired be developed to
form a complete screw which dips into the pulp to be lifted, and, when provided
with a surrounding casing or envelope, serves to supply the pulp to the mill.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, we declare that what we
claim is :-
1. A centrifugal mill provided with a circulation vessel and suitable for separating
or disintegrating cellular substance and mixing and washing paper pulp comprising
a ring of hollow pins through which water is adapted to be passed and spirted
against pins projecting from a rotating disc whereby the water is sprayed outwardly
and a sucking action is induced by which the material being treated is caused
to pass as many times as desired between the two sets of pins above referred to and
thus become intimately mixed with the water substantially as described.
2. A centrifugal mill or apparatus suitable for separating or disintegrating
cellular substance and mixing and washing paper pulp constructed substantially as
berein described with reference to and shown in the accompanying drawings
whether or not water be supplied through the lower pine d or direct to the
circulation-vessel a lifting device being provided in the latter case to deliver the
material to be treated to the mill as set forth.
Dated this 23rd der of Wahr
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