Improvements in the Method of and Means for Separating Knots and other Matters from Wood Fibre in the Manufacture of Wood Pulp.
Year: 1895

page_text: Date of Application, 22nd Aug., 1895
Complete Specification Left, 9th May, 1896-Accepted, 13th June, 1896
PROVISIONAL SPECIFICATION.
[Communicated from abroad by NILS PEDERSEN, of Borregaard, Sarpsborg, in
the Kingdom of Norway, Engineer.]
Improvements in the Method of and Means for Separating Knots
and other Matters from Wood Fibre in the Manufacture of Wood
Pulp.
We, THE KELLNER PARTINGTON PAPER PULP CO. LIMITED, of 11 New-
market Lane Manchester in the County of Lancaster, Paper Manufacturers, do
hereby declare the nature of this invention to be as follows:-
The logs, billets and pieces of wood commonly employed as the source of
lignocellulose in the manufacture of wood pulp contain, after they have been
barked, knots dirt pieces of bark and other matters which it is necessary or desirable
to remove. It is usual to effect this removal, as far as is practicable, by boring
the knots out of the barked logs, or, as hereinafter described, during the subsequent
treatment of the pulp. The boring process not only has the defect that it is
tedious and costly, but the further serious defect that in thus removing the
worst of the knots a considerable quantity of good wood is also necessarily bored
out and wasted.
Such bits of knotty material, dirt and other foreign matters as are not removed
by the boring process are sometimes attempted to be removed during the manu-
facture of paper from the wood pulp. For this purpose, the pulp is added to a
large quantity of water wherein the knotty and other foreign matters should sink
because of their greater density, whilst the pure lignocellulose should float and
thus be capable of easy separation. But, in practice, it is found that because of
air bubbles and air films adhering to the foreign matters, and for other reasons
which are not clearly ascertained, a very large proportion of these foreign
matters, notwithstanding their greater density, fail to sink, and remain in the pulp.
Moreover, this process does not avoid the objection that the foreign matters not
removed by boring have to be passed through and dealt with in the digesters.
The object of this invention is to effect the removal of the before mentioned
foreign matters from the wood before the process of boiling or digestion, by simple
and effective and convenient means, and in such a manner that the necessity for
boring out the knots may be entirely obviated, although it may, to some extent,
still be employed if desired, for the removal of the larger knots.
In proceeding according to this invention, the barked logs billets or other pieces
of wood are reduced to chips and disintegrated as at present, with or without
some preliminary boring out of the larger knots. The disintegrated wood is then,
before boiling or digestion, placed in a liquid such as water or a saline or other
solution baving a greater specific gravity than that of the good wood required for
the manufacture of the pulp, and less than that of the foreign matters to be
removed.
For all woods commonly used, water fulfils the required condition. The liquid
is contained in a suitable tank or vessel to one end of which the disintegrated wood
is continuously or intermittently supplied. It is, by preference, removed from the
opposite end. Whilst the disintegrated wood is in the liquid, it is subjected to the
action of devices which submerge it in the liquid, preferably over and over again,

page_text: so as to thoroughly wet it and remove all the adhering air bubbles and films. The
foreign matters being thus rendered non-flotative, sink to the bottom whence they
may be removed by suitable means. The floating matters which consist of
practically pure woody fibre may also be separately removed by suitable means.
The disintegrated wood may, for example, be supplied to the tank by an endless
travelling apron, and be submerged by means of paddles. After repeated
submergencies the floating wood may be removed by scrapers up an inclined plane
provided with a perforated false hottom for drainage, and delivered to a bydro-
extractor or other receptacle. The deposited foreign matter may be delivered at
one end of the tank by an Archimedean screw, and be removed by an elevator and
delivered to a vessel arranged to receive it.
Dated this 20th day of August A.D. 1895.
W. E. HEYS & SON,
Agents for the Applicants.
Improvements in the Method of and Means for Separating Knots
and other Matters from Wood Fibre in the Manufacture of Wood
Pulp.
We, THE KELLNER PARTINGTON PAPER PULP COMPANY LIMITED of
11 Newmarket Lane, Manchester, in the County of Lancaster, Paper Manufacturers,
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 logs, billets and pieces of wood commonly employed as the source of
ligno-cellulose in the manufacture of wood-pulp contain, after they have been
barked, knots, dirt, pieces of bark, and other matters which it is necessary or
desirable to remove. It is usual to effect this removal, so far as is practicable,
by boring the knots out of the barked logs, or, as hereinafter mentioned, during
the manufacture of the paper or other articles from the wood-pulp.
The boring process not only has the defect that it is tedious and costly, but the
further serious defect that in thus removing the worst of the knots, a considerable
quantity of good wood is also necessarily bored out and wasted. Such bits of
knotty material, dirt and other foreign matters as are not removed by the boring
process, are sometimes attempted to be removed during the manufacture of the
paper from the wood-pulp. For this purpose, to the pulp is added a large
quantity of water wherein the knotty and other foreign matters should sink,
because of their greater density, whilst the pure ligno-cellulose should float and
thus be capable of easy separation. But, in practice, it is found that because of
air bubbles and air films adhering to the foreign matters, and for other reasons
which are not clearly understood, a very large proportion of the foreign matters,
notwithstanding their greater density, fail to sink, and remain in the pulp.
Moreover, this process is open to the objection that the foreign matters not
removed by boring, have to be passed through and dealt with in the digesters.
The object of this invention is to effect the removal of the before mentioned
foreign matters from the wood before the process of boiling or digestion, by simple
effective and convenient means, and in such a manner that the necessity for boring
out the knots may be entirely obviated, although it may, to some extent, be still
employed, if desired, for the removal of the larger knots.
If proceeding according to this invention, the barked logs, billets or pieces of
wood are reduced to chips and disintegrated as at present, with or without some
preliminary boring out of some of the larger knots. The disintegrated wood is.

page_text: then, before boiling or digestion, placed in a liquid such as water or a saline or
other suitable solution having a greater specific gravity than that of the good
wood required for the manufacture of the pulp, and less than that of the foreign
matters to be removed. For all woods commonly used, water fulfils the required
condition. This liquid is contained in a suitable tank or vessel, to one end of which
the disintegrated wood is continuously or intermittently supplied. It is, by
preference, removed from the opposite end. Whilst the disintegrated wood is:
in the liquid, it is subjected to the action of appliances which submerge it, prefer-
ably over and over again, so as to thoroughly wet it and remove all the adhering
air bubbles and films. The foreign matters being thus rendered non-flotative;
sink to the bottom, whence they may be removed, by suitable means such as are.
hereinafter described by way of example. The floating matters, which consist of
practically pure woody fibre, may also be separately removed by appliances an
example of which is hereinafter described.
Apparatus of various constructions may be employed for the separation, as.
hereinbefore described, of the good woody fibre and the heavier matters, but that
illustrated by the accompanying drawings is found to be convenient in practice and
is, at present, preferred to be used.
In these drawings, Figure 1 represents a longitudinal section, and Figure 2 a
transverse section along the line a-b Figure 1.
A is the terminus of an endless band or apron a by means of which the disin-
tegrated wood may be supplied to the tank B, which contains the requisite liquid.
Paddles C, rotating in the direction indicated by the arrows, are arranged at about
the level of the liquid in the tank, in such a manner that the floating matters, in
passing from the supply end of the tank to the removal end, are submerged by
them in succession. At the removal end of the tank, there is an inclined plane D,
above which the endless aprons or equivalent endless chains E move in the direction
indicated by the arrows. This endless apron carries the scrapers F at right angles.
thereto, and passes around the pulleys G G¹ by one or by both of which the apron
may be driven. The scrapers whilst passing round the lower are of the lower
pulley, dip below the surface of the liquid, and thus remove therefrom the floating
wood to the inclined plane, up which it is carried by the continued motion of the
scrapers. The disintegrated pure wood is finally delivered from the upper end
of the inclined plane, whence it drops into a receiver H, which may be a hydro-
extractor.
To provide for the separation of the free liquid which may be removed from the
tank with the disintegrated wood, the inclined plane D may be fitted with a
perforated false bottom, indicated by the line I, and at the bottom of the inclined
plaue there may be arranged the receiving trough K for the returning liquid,.
whence it may flow into the tank or away through the outlet L.
An Archimedean screw M, may be arranged longitudinally in the bottom of the
tank, aud be rotated by suitable gearing in the direction indicated by the arrow, so
as to convey away the sunken matters towards the receiver N, shewn in sectional
elevation by Figure 2. The bottom of the tank may be advantageously sloped
from each side towards the Archimedean screw, so as to lead the deposited matters.
thereon, as indicated by the dotted lines O Figure 2.
In the receiver N, to which the deposited matters are conveyed by the screw,.
through an opening in the end of the tank, there is an elevator P moving in the
direction indicated by the arrow. As the deposited matters arrive at the receiver,.
they are removed by the elevator, from the upper end of which R they fall into
any suitable vessel S arranged for their reception.
The surplus liquid is removed from the separated disintegrated wood by a hydro-
extractor or otherwise, as is well understood, and the wood is then treated in the
usual manner for the manufacture of pulp.
The appended drawings are diagrammatic, no gearing for driving the moving
parts being shewn, nor various other accessories, the construction and arrangement
of all of which are well understood.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In the manufacture of wood pulp, placing the disintegrated wood, with or
without the prior partial removal of the knots, in a suitable liquid such as water
and submerging it so as to remove adhering air, withdrawing the floating wood,
and subsequently removing the surplus liquid therefrom preparatory to boiling or
digestion, substantially as herein before described.
2. Apparatus for treating disintegrated wood for the removal therefrom of
matters heavier than the wood itself, consisting essentially of a vessel to contain
liquid, paddles or similar appliances for submerging the disintegrated wood, and
means for removing the separated floating wood and the deposited matters
respectively from the vessel, constructed arranged and operated substantially as
herein before described with reference to the accompanying drawings.
3. In the manufacture of wood pulp, the herein before described process for
the separation from the wood of heavier matters, before boiling or digestion
and without the preliminary boring for the removal of the knots, substantially as
set forth.
Dated this 6th day of May. A.D. 1896.
W. E. HEYS & SON,
Agents for the Applicants.