Improvements in the Process of and Means for Purifying Paper Pulp.
Year: 1890

page_text: Date of Application, 29th Mar., 1890
Complete Specification Left, 29th Apr., 1890-Accepted, 14th June, 1850
PROVISIONAL SPECIFICATION.
Improvements in the Process of and Means for Purifying
Paper Pulp.
I, CARL KELLNER, of Bartensteingasse 8, Vienna I, Austria, Chemist, do hereby
declare the nature of this invention to be as follows:-
It has heretofore been usual to purify paper pulp exclusively by devices, which act
as sieves, that is to say which allow the smaller particles to pass, while they retain the
coarser ones such as knots, knobs, splints, etc.; or by devices, in which the impurities
of the pulp are eliminated by causing a slow stream of greatly diluted pulp to flow
over stops, by which the heavier particles are retained in consequence of their
sinking.
It is a well known fact to those versed in paper making that the numerous kinds
of apparatus having a shifting action, which are in use, as well as the device known
as a "sand-trap" fulfil their purpose in a very defective manner. Sand-traps cannot
be used at all except for eliminating particles whose specific gravity differs con-
siderably from that of the fibres, and such for instance as sand, lime, gypsum, coarse
knobs etc. Should the liquid in which the paper pulp fibres are suspended be caused to
flow so slowly over the sand-trap that smaller or lighter impurities could settle, a
great deal of good paper stuff would be lost, as it would likewise settle.
Now, this invention comprises a process, having none of the disadvantages referred
to and which renders it possible to purify the paper pulp far more thoroughly than
has been the case with known methods for this purpose.
According to the invention the object in view is attained by causing the paper pulp,
diluted with much water (one gallon of water per from 15 to 15 ounces according
to the nature of the fibre), to flow into a revolving vessel, or by imparting a whirling
motion to the diluted pulp enclosed in a fixed vessel. In both cases the impurities
are separated from the paper stuff by their being, although they may be but little
heavier, thrown toward the sides of the vessel, whence they may be extracted without
difficulty, while the purified pulp is taken from the middle portion of the liquid
contained in the vessel.
The annexed sheet of drawings shows sectional elevations of apparatus, by means
of which the said process may be carried into practice.
Fig. 1 shows a cage B, which is enclosed in a casing A and secured to a vertical
shaft. Into the said cage the paper pulp is caused to enter through a pipe a enclosing
the shaft and extending downward nearly to the bottom of the cage. As the cage
is rapidly rotated, the heavier of the particles suspended in the water are thrown
toward the sides of the cage, while the purified pulp rises through the shorter
pipe 6 surrounding the pipe a, and thence passes into a suitable conduit c, conveying
the pulp to the desired point.
The liquid continually entering the cage displaces the liquid already contained'
therein, whereby the heavier particles thrown toward the circumference are caused
to rise along the sides of the cage and to pass into the casing A, whence they may
be drawn off through the aperture d.
The centrifugal pulp purifier shewn by Fig. 2 is of a somewhat modified form, and
its cage B is provided with an annular plate e, supported by three or more arms or
brackets e', which extend inward radially from the side of the cage B. The annular
plate e is intended to oppose to the liquid, admitted through the pipe a, a certain
resistance while the cage B is rapidly revolving, whereby more time is afforded to
the suspended particles for separating according to their specific gravities. The
heavier particles thrown toward the sides of the cage rise along the brackets el as
they are displaced by subsequent portions, and finally they pass over the brim of the
cage into the casing A, whence they are run off through the aperture d,

page_text: The purified paper pulp is drawn off through the pipe b.
Fig. 3 shows an apparatus in which the vessel B, which receives the paper pulp
diluted with water through the pipe a; is immovable; a whirling motion is imparted
to the liquid by an agitator or paddle wheel f, arranged beneath the orifice of the
pipe a, by which arrangement, the separation of the heavier suspended particles
from the lighter ones is also effected. The latter escape through the pipe b which
may enclose the pipe a or may be arranged as shewn in dotted lines. On the other
hand the heavier particles are caused to rise along the sides of the vessel B by
freshly entering liquid, and pass into the casing g whence they flow out through the
spout h.
Dated this 29th day of March 1890
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Process of and Means for Purifying
Paper Pulp.
I, CARL KELLNER, of Bartensteingasse 8, Vienna I, Austria, Chemist, do hereby
declare the nature of this invention and the manner in which the saine is to be
performed to be particularly described and ascertained in and by the following
statement:
It has heretofore been usual to purify paper pulp exclusively by devices, which act
as sieves, that is to say which allow the smaller particles to pass, while they retain the
coarser ones such as knots, knobs, splints, etc.; or by devices, in which the impurities
of the pulp are eliminated by causing a slow stream of greatly diluted pulp to flow
over stops, by which the heavier particles are retained in consequence of their
sinking.
It is a well known fact to those versed in paper making that the numerous kinds of
apparatus having a sifting action, which are in use, as well as the device known as a
"sand-trap
"fulfil their purpose in a very defective manner. Sand-traps cannot be
used at all except for eliminating particles whose specific gravity differs considerably
from that of the fibres, and such for instance as sand, lime, gypsum, coarse knobs, etc.
Should the liquid in which the paper pulp fibres are suspended be caused to flow so
slowly over the sand-trap that smaller or lighter impurities could settle, a great deal
of good paper stuff would be lost, as it would likewise settle.
Now, this invention comprises a process, having none of the disadvantages referred
to, and which renders it possible to purify the paper pulp far more thoroughly than
has been the case with known methods for this purpose.
According to the invention the object in view is attained by causing the paper
pulp, diluted with much water (1 gallon of water per from 1-5 to 15 oz., according to
the nature of the fibre), to flow into a revolving vessel, or by imparting a whirling
motion to the diluted pulp enclosed in a fixed vessel. In both cases the impurities
are separated from the paper stuff by their being, although they may be but little
heavier, thrown toward the sides of the vessel, whence they may be extracted without
difficulty, while the purified pulp is taken from the middle portion of the liquid
contained in the vessel.
The sheet of drawings filed with my Provisional Specification shews sectional
elevations of apparatus, by means of which the said process may be carried into
practice.
Fig. 1 shews a cage B, which is enclosed in a casing A. and secured to a vertical
shaft. Into the said cage the paper pulp is caused to enter through a pipe a
enclosing the shaft and extending downward nearly to the bottom of the cage. As
the cage B is rapidly rotated, the heavier particles suspended in the water are
thrown toward the sides of the cage, while the purified pulp rises through the

page_text: shorter pipe b, surrounding the pipe a, and thence passes into a suitable conduit c,
conveying the pulp to the desired point.
The liquid continually entering the cage displaces the liquid already contained
therein, whereby the heavier particles thrown toward the circumference are caused
to rise along the sides of the cage and to pass into the casing A, whence they may be
drawn off through the aperture d.
'
The centrifugal pulp purifier shewn by fig. 2 is of a somewhat modified form, and
its cage B is provided with an annular plate e, supported by three or more arms or
brackets e, which extend inward radially from the side of the cage B. The annular
plate e is intended to oppose to the liquid, admitted through the pipe a, a certain
resistance while the cage B is rapidly revolving; whereby more time is afforded to
the suspended particles for separating according to their specific gravities. The
heavier particles thrown toward the sides of the cage rise along the brackets el as
they are displaced by subsequent portions, and finally they pass over the brim of the
cage into the casing A, whence they are run off through the aperture d.
The purified paper pulp is drawn off through the pipe b.
Fig. 3 shews an apparatus, in which the vessel B which receives the paper pulp
diluted with water, through the pipe a, is immovable. A whirling motion is imparted
to the liquid by an agitator or paddle-wheel f, arranged beneath the orifice of the
pipe a, by which arrangement, the separation of the heavier suspended particles from
the lighter ones is also effected. The latter escape through the pipe b, which may
enclose the pipe a or may be arranged as shewn in dotted lines. On the other hand,
the heavier particles are caused to rise along the sides of the vessel B by freshly
entering liquid, and pass into the casing 9, whence they flow out through the
spout h
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The herein before described process of purifying paper pulp from heavier particles
mixed therewith, such as knots, splints, and the like, the said process consisting in
imparting to the pulp, previously diluted with much water, a rapid rotary motion,
whereby the heavier particles are caused to gather in the portion most distant from
the axis of rotation and may thence be drawn off, while the purified pulp may be
drawn off from the portion near the said axis.
Dated this 29th day of April 1890.
C. KELLNER,
Per L. W.