Improvements in Apparatus for Sorting Particles of Material of Equal Size According to Density.
Year: 1895

page_text: Date of Application, 1st Feb., 1895
Complete Specification Left, 9th Oct., 1895-Accepted, 9th Nov., 1895
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Sorting Particles of Material of
Equal Size According to Density.
I, LUDWIG PIETTE, of Pilsen, Bohemia, in the Empire of Austria, Manu-
facturer, do hereby declare the nature of this invention to be as follows:-
My invention relates to apparatus for sorting particles of material of equal size
and particularly pieces of wood for the manufacture of cellulose according to
density, so that the denser knotty pieces and the pieces of trunk wood immediately
surrounding knots and which are unsuitable for the manufacture of cellulose will
be separated from the good pieces which are less deuse.
My improved apparatus operates as follows: The pieces of wood of equal size
are thrown at equal initial velocity and under the same angle through air the latter
being perfectly immovable or moved at a small velocity in the opposite direction to
that of the throw.
As the pieces of wood are of equal size and are thrown at the same initial speed
they meet with the same resistance of air during the throw, and as the initial value
of the energy of the less dense pieces which are suitable is smaller than that of
the denser pieces which are unsuitable, the length of throw will be less with the
former than with the latter pieces, so that they will be separated from each other
according to their density and suitability and that the selection of the knotty
pieces by hand is completely or almost entirely obviated.
The appropriately reduced material is separated according to the size of the
pieces by any well known apparatus having sieves of different size of mesh. The
pieces of equal size are then introduced into the throwing apparatus which is
constructed as follows: An endless apron which passes around rollers is driven by
one of the said rollers which is revolved at a high but uniform speed. This apron
is partly covered by another endless apron passing around rollers and driven at the
same speed as the first apron.
The material is introduced between the two aprons and is carried away by them
whereby it acquires a great speed.
Instead of the second apron a roller of larger diameter may be used which is
revolved at a high speed and carries with it the first mentioned endless apron.
With the high speed thus acquired the picces of material are thrown beyond the
roller and fall into troughs the bottoms of which are formed by aprons travelling
along side by side and carrying the material from the troughs into suitable
receptacles. The particles of the material being introduced between two surfaces
moving at equal speed and being carried on by such surfaces, all the particles will
acquire the same speed, and as these particles are carried on by the apron until
the moment of throw the direction of throw will be the same for all particles.
The length of throw therefore only depends on the density of the particles and
is shortest for the least density; hence the least dense particles which are suitable
for the manufacture of cellulose will fall into the first trough whereas the knotty
pieces or dense trunk wood surrounding knots fall into the third trough. The
second trough receives an inferior sort of good wood with a slight addition of small
kuots. This part of the material may be used for producing an inferior kind of
cellulose, or may be sorted by hand or may again be introduced into a throwing
apparatus and treated as described.

page_text: I am aware that it has been proposed to use for sorting particles of equal size
according to density an apparatus in which the material is introduced between a
uniformly revolving roller and a stationary shield partly surrounding such roller.
Such apparatus however is objectionable because neither a uniform initial velocity
nor a uniform angle of throw is obtained thereby with certainty for all particles
thrown. Therefore the length of throw will with such apparatus depend not only
of the density of the particles but also of a variety of other uncontrollable
circumstances which renders the separation very imperfect. By my invention I
avoid these objections because the material is introduced between two surfaces
moving at the same speed (either two aprons or an apron and a roller) whereby an
exactly uniform initial velocity and exactly the same angle of throw is obtained
for all particles.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in Apparatus for Sorting Particles of Material of
Equal Size According to Density.
I, LUDWIG PIETTE of Pilsen, Bohemia, in the Empire of Austria, 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 :-
My invention relates to apparatus for sorting particles of material of equal size
and particularly pieces of wood for conversion into cellulose according to their
density, so that the denser knotty pieces and the pieces of trunk wood immediately
surrounding knots and which are unsuitable for conversion into cellulose will be
separated from the suitable pieces which are less dense.
My improved apparatus operates as follows: The pieces of wood of equal size
are thrown at equal initial velocity and at the same angle through air the latter
being perfectly motionless or only moving at a small velocity in the opposite
direction to that in which the pieces of wood are thrown.
As the pieces of wood are of equal size and are thrown at the same initial
speed they all meet with the same resistance in their passage through the air, and
as the initial energy of the less dense pieces which are suitable for conversion
into cellulose is smaller than that of the denser pieces, which are unsuitable,
therefore the former will travel less far than the latter pieces, so that the pieces
will be separated from each other according to their density and suitability for
conversion into cellulose and that the selection of the knotty pieces by hand is
entirely or almost entirely obviated.
In the accompanying drawing,
Figure 1 is a side elevation of an apparatus constructed in accordance with my
invention
Figure 2 is a plan of the same and
Figure 3 shows a modification of the throwing apparatus.
The appropriately reduced material is separated according to the size of the
pieces by any well known apparatus having sieves of different size of mesh. The
pieces of equal size are then introduced into the throwing apparatus which is
constructed as follows: V is an endless band which passes around rollers d d and
is driven by one of the said rollers which is caused to revolve at a high but uniform
speed. The said band is partly covered by another endless band V₁ passing around
rollers d' d' d' and driven at the same speed as the band V.

page_text: The pieces to be sorted are introduced between the two bands V V₁ at a and
is carried away, by them whereby the said pieces acquire a great speed.
Instead of the band V' a roller W of large diameter may be used as shown in
Figure 3 which is revolved at a high speed and carries with it the endless band V.
With the high speed thus acquired the pieces of material are thrown beyond the
roller d and fall into troughs K', K, K³ the bottoms of which are formed by
endless bands W W W travelling along side by side and carrying the material
from the troughs into suitable receptacles.
The particles of the material being introduced between two surfaces moving at
equal speed and being carried on by such surfaces, all the particles will acquire the
same speed, and as these particles are carried on by the band V until the moment
at which they are thrown forward the direction of throw will be the same for all
particles, namely the direction of the part of the band V going to the roller d*.
The distance through which the particles are thrown therefore only depends on
their density and is shortest for the least dense particles; hence the least dense
particles which are suitable for conversion into cellulose will fall into the first
trough K whereas the knotty pieces or dense trunk wood surrounding knots will
fall into the third trough K³. The second trough K' receives an inferior sort of
wood with a slight addition of small knots. This part of the material may be
used for conversion into an inferior kind of cellulose, or may be sorted by hand or
may again be introduced into a throwing apparatus and treated as described.
I am aware that it has been proposed to use, for sorting particles of equal size
according to their density, an apparatus in which the material is introduced
between a uniformly revolving roller and a stationary shield partly surrounding
such roller. Such apparatus however is objectionable because neither a uniform
initial velocity nor a uniform angle of throw is obtained thereby with certainty
for all particles thrown. Therefore the length of throw with such apparatus
depends not only on the density of the particles but also on a variety of other
uncontrollable circumstances which render the separation very imperfect. By my
invention I avoid these objections by introducing the material between two surfaces
moving at the same speed (either two endless bands or one band and a roller)
whereby an exactly uniform initial velocity and exactly the same angle of throw
is obtained for all particles.
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 :-
For separating particles of material of equal size according to density, a
throwing apparatus, comprising an endless band led around suitable guiding and
carrying rollers and driven by any of them at a high speed and a second similar
endless band partly covering the former, or the first mentioned endless band and a
roller partly surrounded by such a band and driven by it, so that the particles
introduced between the bands or the band and the roller respectively are carried
on by them and thrown at a uniform initial velocity whereby owing to the
resistance of the air the length of throw will be shorter for the less dense pieces
than for the denser pieces.
בו
Olof Oatch. 1905
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.