Process and Apparatus for the Unbarking of Wood.
Year: 1892

page_text: te of Application, 15th June, 1892-Accepted, 13th Aug., 1892
COMPLETE SPECIFICATION.
Process and Apparatus for the Unbarking of Wood.
I, PETER JENSEN of 77 Chancery Lane in the County of Middlesex, Chartered
Patent Agent do hereby declare the nature of this invention (a communication
from Carl Bache-Wüg, Manufacturer and Einar Morterud, Mechanical Engineer,
both of Böhnsdalen, Norway) and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
This invention refers to a process for unbarking wood logs or branches.
The main advantages of this new process, as compared with previous ones such
for instance as those used in the manufacture of cellulose and wood pulp, consist in
the small driving power required and in the preservation of the wood from being
damaged.
The invention is based upon the observation that wood when left floating in
water for a length of time and while thrown hither and thither in stormy weather
or in passing through waterfalls very soon loses its bark. This led to the con-
clusion that the bark can be very easily knocked off when it is thoroughly
wetted.
In order to produce artificially what takes place every day in nature the round
trunks of wood are cut up into suitable lengths, and thrown and rolled against
each other in a rotatable drum while submitted to the simultaneous action of a
liquid. In consequence of the knocking and rubbing action the bark is mostly
loosened from the wood and collects in the drum in pieces. The patches of bark
that may still adhere at the branch roots and in recesses may then be removed
with little trouble for instance by means of brushes.
It appears therefore to be suitable to act with brushes upon the whole length
of the log in order to make sure in all cases that every trace of the bark is
removed.
The rolling about of the logs as well as the treating of the same with brushes
is done under water, and as a moderate heat furthers the intended action, the lye
which has been used for boiling the cellulose may be applied, if the unbarking
process is carried on in a cellulose factory.
It is also to be recommended to let the wood remain in the liquid some time.
For carrying out this process an apparatus such as illustrated by the accom-
panying drawings may be applied; these shew two modes of carrying out the
process.
In Figs. 1 and 2 the apparatus consists of a drum A which by means of two
bosses with arms a is fixed on a spindle B having its bearings in two opposite walls
of a vessel C. The spindle B is rotated by means of a tooth wheel c' thereon
and driven by a pinion on a spindle provided with fast and loose strap pulley as
shewn. The drum A may be of wood or of other suitable material. The end
walls D of the drum are fixed in a ring d which is bolted to the arms a, and the
circumference of the drum consists of a number of rectangular staves e also fixed
to the ring d and with equal spaces between them. E is a door or flap for
introducing the logs into the drum, which when about half full of them is rotated.
The logs then roll, rub and knock against each other until the bark is loosened.
In the apparatus shewn in Figs. 3 and 4 no outer vessel is provided. The
liquid is contained in a watertight drum F and is introduced through one hollow
central gudgeon pipe 9 and carried off by another gudgeon pipe g¹.
In the interior of the drum F are provided bars H arranged concentrically near
the circumference and screwed into the end walls f. In order to provide for
introduction of the logs, some bars H are omitted at the lid or flap I and instead
of them the lid is provided with bars bent into U shape. The mode of action
TD 077

page_text: is the same as in the firstly described apparatus. When the logs have been
treated and the bark nevertheless has not been completely removed the logs are
further acted upon with brushes for instance by means of a brushing machine
such as described in my Patent Specification bearing even date herewith
No. 11264.
Instead of using clean water in the above described process the lye_may be
applied which has been used for boiling in the cellulose manufacture. In some
cases, when no such lye is available, a lye may be made artificially. A thin soda
solution then suffices. Even waste water of any kind may be used for the
purpose of this invention. If such liquids before being applied to the unbarking
of wood logs have been much cooled down it is well to heat them a little.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim:-
1. The process for unbarking wood logs consisting in treating them under water
or other liquid by preference heated in a rotating drum in such manner that the
bark in consequence of the rolling and rubbing action becomes loosened without
hurt to the wood.
2. For carrying out the process firstly claimed a drum having bars at or near
the circumference arranged at suitable distances apart and either rotated in a
vessel containing liquid which enters the drum, or surrounded by an outer closable
mantle rotating therewith and serving as the liquid container.
3. The constructions of apparatus shewn on the drawing.
חד מ מזןב ז500
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.