A Process for Straining Woody and similar Fibrous Substances in Suspension, and Apparatus therefor.
Year: 1896

page_text: Date of Application, 5th Feb., 1896-Accepted, 14th Mar., 1896
COMPLETE SPECIFICATION.
A Process for Straining Woody and similar Fibrous Substances in
Suspension, and Apparatus therefor.
We, IVAR AXEL FERDINAND WALLBERG, of Karlstads Mekaniska, Verkstad,
Karlstad, and JOHAN DANIEL ULLGREN, of Wermbol, Katrineholm, both in the
Kingdom of Sweden, Engineers, 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 :-
This invention relates to a process for straining wood pulp or the like and similar
fibrous substances, the said process consisting in conducting the fibres, which are
suspended in water or in any other fluid, through a fixed tube or drum which is
composed either wholly or partially of sieve or strainer plates, and in communi-
cating to the fluid contained in the said tube or drum an undulatory vibrating
motion so that it is alternately sucked away from the siere plates and driven
against the same.
To enable our invention to be fully understood we will describe the same by
reference to the accompanying drawing in which a form of apparatus for carrying
out the same is shewn, and in which :-
Figure 1 is a longitudinal section of the apparatus :
Figure 2 is a plan:
Figure 3 is an end view, and,
Figure 4 a cross section of the same.
The apparatus consists of a vessel or container 1 of wood or metal and divided
into compartments or divisions 2, 3, 4 and 5. In compartment 3 we arrange a tube
or drum 13 which tube may be made square, round or of any other suitable shape
in cross section and the walls or sides of which are composed either partially or
wholly of sieve or strainer plates. The perforations or holes of the sieve plates
are preferably slit-like in form arranged along the length of the tube, and the
breadth of the slits is advantageously from 1 to 0.1 millimetres. The whole of the
drum 13 can be formed of such sieve or strainer plates or the said plates may form
only part of the drum, the rest of the latter being made unperforated. The tube
or drum may be either so fixed that two of the sides are vertical in the case of a
square drum or the ends of the drum can be held in rings 14 which are supported.
in corresponding rings arranged around the orifices in the partitions between the
compartments 2 and 3 and 3 and 4 respectively so that the drum can revolve on its
horizontal axis for the purpose of allowing the sieve or strainer plates to be cleaned
with facility.
In compartment 2. a shaft 6 is supported in bearings which shaft can have a
rocking or oscillating motion communicated to it from the driving shaft 8 and by
means of the arm 7 and of a small eccentric on the shaft 8. On the shaft 6 we
provide a clamp 9 in which an elastic rod or plate 10 of wood or metal, one end of
which projects into the tube or drum, can be clamped or screwed. The other end
of the rod can also if desired be connected with a similar oscillating device. In
order to insert and to remove this rod the outer wall of compartment 2 is provided
with a door 15. The side walls of division 3 can be provided with suitable adjustable
overflow lips or flanges 11 for the fibres which have passed through the sieve or
strainer and the wall between the division 4 and the outlet gutter or channel 5 is
provided with an adjustable overflow iip or flange 12 for those fibres which have
not passed through the sieve plates.

page_text: The operation of the apparatus is as follows,-The fibrous mass suspended
in the fluid is poured into compartment 2 and flows into and through the tube or
drum 13 with a velocity suitable for the quality or condition of the material to be
treated As the fluid flows through the tube the successive layers of fluid will
move forward with somewhat varying velocity on account of the friction which is
caused by the contact of the mass with the walls of the tube. As a consequence
of this the fibres during the flow come to lie in the direction of the longitudinal
axis of the tube and of the slits. On account of the wave-like vibrating motion
of the rod the fibrous mass is alternately driven against the sieve or strainer plates
and sucked away from the same whereby those fibres which can pass through the
slits do so whilst those fibres which, during the flow through the tube, in spite of
the aforesaid motion do not pass through the slits pass out of the tube and flow
over the overflow lip or flange 12 into the outlet gutter or channel 5 from which
they can be again conducted into compartment 2 or into the corresponding
compartment of another similar apparatus. By suitably choosing the thickness of
the rod or plate 10 and the velocity of the driving shaft 8 the character or quality
of the undulatory motions and of the vibrations can be made to suit different
kinds of fibres and different degrees of sorting. The velocity with which the
mass flows through the tube can be regulated by varying the level of the fluid in
the compartments 2 and 3.
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. A process for straining wood pulp or other fibrous substances, consisting in
continuously conducting the water or other fluid in which the fibrous material is
suspended through a tube or drum which is composed partially or wholly of sieve
or strainer plates and in causing the fluid to 'alternately recede from and strike
against the sides of the tube through the medium of an elastic rod or plate arranged
in the tube and having an undulatory vibrating motion in the direction of the length
of the tube, substantially as described.
2. Apparatus for carrying out the process described in Claim 1, cousisting of a
tube 13 of any suitable cross section and composed wholly or partially of sieve or
strainer plates, in which tube an elastic rod or plate 10 is arranged which is
connected at one or both ends with a suitable arrangement (such as for instance
an eccentric) adapted to impart an undulatory vibrating motion to the rod or plate,
substantially as described and illustrated in the drawing.
3. In apparatus of the kind described in Claim 2 forming the slits in the sieve
or strainer plates longitudinally in the tube 13.
4. In apparatus of the kind described in Claim 2 mounting the tube 13 rotatably
in the partitions of the vessel or container for the purpose of enabling the sieve or
strainer surface to be easily cleaned.
Dated the 5th day of February 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.