Year: 1888

page_text: I, LUDWIG PIETTE of Pilsen, Bohemia, in the Empire of Austria, Paper manufacturer
do hereby declare the nature of this invention to be as follows:-
Up to the present time the knots of the wood used for the manufacture of cellu-
lose were bored out or stamped out or sorted out by hand after the wood was
disintegrated.
This method is not only expensive but also takes up a great amount of time and
is moreover dangerous for the workmen because of the machines used.
The object of the present invention is to sort the knots from the other wood
automatically by mechanical means.
A machine for this purpose consists principally of two endless sieves running
round rollers. These sieves are arranged one above the other and the lower part
of the upper sieve passes near and horizontally over the horizontal upper part of the
lower sieve. The rollers carrying the sieves are preferably of the same diameter and
revolve with the same peripheral speed so that the horizontal parts of the sieves (these
sieves being moved in opposite directions) move together at the same speed in the
same direction.
Within the upper sieve directly over the lower or horizontal part thereof is arranged
a box or chamber open at the bottom from which box the air is continuously drawn
off by means of an exhauster or other suitable means so that there is a permanent
current of air through the openings of the horizontal lower part of the upper sieve.
The disintegrated wood is fed onto the upper or horizontal part of the lower sieve
and all those parts of wood which are free from knotty parts are drawn up against
the upper sieve by the current of air and remain there while the heavier knotty parts
remain on the lower sieve, travel with this and fall into a receptacle at the point where
the lower sieve moves downwards. The lighter parts of the wood are carried on with
the upper sieve which extends beyond the lower one until they pass beyond the in-
fluence of the air current when they fall into receptacles placed underneath. On

page_text: this end of the air box is arranged a partition provided with openings which reduces
the air current so that parts of wood adhering to the upper sieve which still contain
small parts of knots or were round the-knots and are therefore somewhat heavier will
fall into a receptacle while the light parts free from all traces of knots still adhere to
the sieve until they pass beyond the air box.
In a modified form of the machine the horizontal parts of the two sieves are further
apart and a series of blast pipes is arranged underneath the horizontal part of the
lower sieve by means of which a current of air is driven through the lower sieve
which will throw the lighter parts of wood against the upper sieve while the heavier
knotty parts remain on the lower sieve.
A further modification consists in using a sieve drum. The air from the interior of
this drum is continuously exhausted through a tube passing through the hollow axis
of the drum so that the lighter parts of wood fed onto the drum adhere to the drum
while the heavier knotty parts fall from it. The lighter parts adhere to the sievo
until they arrive at a point where a strong current of air is blown through the sieve
from a small chamber in the interior of the drum which current blows the light
particles away from the sieve. The interior of the drum is thus divided into two
chambers, a large one from which the air is exhausted and a small one through which
a current of air is forced outwards.
Dated this 22nd day of December 1888.

page_text: Improved Method of Sorting the Disintegrated Wood for the
Manufacture of Cellulose, and Apparatus therefor.
I, LUDWIG PIETTE of Pilsen, Bohemia, in the Empire of Austria, paper manu-
facturer, 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 :--
Up to the present time the knots of the wood used for the manufacture of cellulose
were bored out or stamped out or sorted out by hand after the wood was disintegrated.
This method is not only expensive but also takes up a great amount of time and is
moreover dangerous for the workinen because of the machines used.
The object of the present invention is to sort the knots from the other wood
automatically by mechanical means.
In the accompanying drawings:-
Fig. 1. represents a side view of one kind of machine.
Fig. 2. represents a vertical section of the same.
Fig. 3. represents a side view of a somewhat modified machine.
Fig. 4. represents a further modification of the machine in drum form.
Fig. 5. represents a vertical section of the same.
The
A machino for this purpose, Figs. 1 and 2, consists principally of two endless
sieves A. B. running round rollers c d e f g h i k journalled in a suitable frame.
These sieves are arranged one above the other and the lower part of the upper sieve
passes near and horizontally over the horizontal upper part of the lower sieve.
rollers carrying the sieves are preferably of the same diameter and revolve with the
same peripheral speed so that the horizontal parts of the sieves move together at the
same speed in the same direction.
Within the upper sieve B directly over the lower or horizontal part thereof is
arranged a box or chamber L open at the bottom, from which box the air is con-
tinuously drawn off (at a) by means of an exhauster or other suitable means, so that
there is a permanent current of air through the openings of the horizontal lower part
of the upper sieve.
The disintegrated wood is fed onto the upper or horizontal part of the lower sieve
in the direction of the arrow I, and all the wood which is free from knotty parts is
drawn up against the upper sieve by the current of air and remains there, while the
heavier knotty parts remain on the lower sieve, travel with this and fall into a
receptacle M at the point where the lower sieve moves downwards.
The lighter parts of the wood are carried on with the upper sieve which extends
beyond the lower one until they pass beyond the influence of the air current when
they fall into receptacles placed underneath. On this end of the air box is arranged

page_text: n partition N provided with openings o. which reduces the air current so that parts of
wood adhering to the upper sieve, which still contain small parts of knots or were
round the knots and are therefore somewhat heavier will fall into a receptacle P. while
the light parts free from all traces of knots still adhere to the sieve until they pass
beyond the air box and then fall into the receptacle Q. In these receptacles are 5
preferably placed screw conveyors which convey the sorted disintegrated wood laterally
out of the machine.
In a modified form of the machine Fig. 3 the horizontal parts of the two sieves are
further apart and a series of blast pipes b. c. d. e. f. g. is arranged underneath the
horizontal part of the lower sieve A by means of which a current of air is driven 1
through the lower sieve, which will throw the lighter parts of wood against the upper
sieve while the heavier knotty parts remain on the lower siove and fall at H into the
receptacle M.
A further modification consists in using a sieve drum T, Figures 4 and 5. The air
from the interior of this drum is continuously exhausted through one part of a divided
tube R passing through the hollow axis of the drum so that the lighter parts of
wood fed onto the drum at A adhere to the drum while the heavier knotty parts fall
from it. The lighter parts adhere to the sieve until they arrive at a point & where a
strong current of air is blown through the sieve from a small chamber G¹ in the
interior of the drum which current blows the light particles away from the sieve.
The interior of the drum is thus divided into two chambers, a large one G from
which the air is exhausted and a small one G¹ through which a current of air is forced
outwards, the tube R being correspondingly divided in two parts K' K' by the
partition Z. N. N are rollers which carry the drum T.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. The method of sorting disintegrated wood consisting in feeding the wood to a
moving sieve on which a suction air current acts in such a manner that the lighter
particles of the disintegrated wood are thereby held against the sieve while the heavier
particles fall off substantially as described.
2. An apparatus for sorting disintegrated wood consisting essentially of an endless
travelling sieve such as A and an endless travelling sieve such as B running in the
same direction and at the same speed over and near the sieve A in the upper sieve B
being arranged a box or chamber such as L open at the bottom from which box the
air is continually drawn, off so that the particles of disintegrated wood fed to the
sieves either remain on the lower sieve or adhere to the upper one according to their
specific gravity and fall either into the receptacle M or are carried forward with the upper
sieve until they reach the end of the box L where a partition such as N regulates the
air current in such a manner that the particles of wood are divided again into two
sorts which fall into their respective receptacles P and Q substantially as described and
illustrated in figure 1 of the accompanying drawings.
3. The method for sorting disintegrated wood consisting in directing an air current
from a series of blast pipes or equivalent against the wood fed to the sieves and which
current will throw the lighter particles of wood against the upper sieve while the
heavier particles will remain on the lower sieve substantially as described.
4. The apparatus for this method substantially as represented in figuro 3 and being
similar in construction to the apparatus represented in figure 1 with the exception tha
the sieves A B are a little farther apart and that under the lower sieve are arranged
the blast pipes or their equivalent substantially as described and illustrated in figure
of the accompanying drawings.
5. The method for sorting disintegrated wood consisting in feeding the disintegrate
wood to a rotating sieve drum in the interior of which a suction air current acts i
such a manner that all lighter particles are attracted by it and held against the siev
drum until they arrive at a certain point where they are blown off by a current passin

page_text: from the interior through the sieve, while the heavier particles fall at once off the
drum partly by their own weight partly in consequence of the centrifugal force
substantially as described.
6. The apparatus for this method substantially as represented in figures 4 and 5
and consisting essentially of a rotating sieve drum such as T through the hollow axis
of which passes a tube divided into two chambers by a partition Z the interior of the
drum being also divided into two chambers such as G. G₁ in one of which acts a
suction air current and in the other a pressure air current substantially as described and
illustrated in figures 4 and 5 of the accompanying drawings.
Dated this 5th day of March 1880