Year: 1899

page_text: Date of Application, 29th Mar., 1899-Accepted, 29th Apr., 1899
I ALBERT BERGSTRÖM, of Bosjön, Finshyttan in the Kingdom of Sweden, Engineer,
do hereby declare the nature of this invention and in what manner the same is
to be performed, to. he particularly described and ascertained in and by the following
statement:-
This invention relates to a rotating filtering or straining apparatus, adapted partly
for use in paper mills and pulp factories for separating water from the pulp and partly
for use in waste water outlets generally, in order to remove floating fibres contained
in the waste water, so that said fibres may be saved and utilized. The apparatus
consists of an ordinary, rotating filtering cylinder, but it is provided with an arrange-
ment which will retain all the fibres in the water, which then flows away completely
free from all solid matter. As is well known many inconveniences arise if the fibres
are not completely removed from the water. Besides a considerable loss of fibre the
presence of the fibre fouls the body of water into which the washing water flows and
injures it in other respects. The clearing basins used in some places are expensive,
occupy a great deal of room and are dependent on the temperature. Besides which
they cause the inconvenience, at least in manufacturing pulp mechanically, that
injurious matters, set free when grinding the wood, stick to the fibres, as they slowly
sink in the water, which matters pollute the fibres and in many cases make them
unsuitable for paper. The ordinary rotating filtering cylinders for collecting the fibres
cannot stop all fibres, because of the manner in which they work. When, in fact, a
small, superficial part of the surface of the cylinder during the rotation in the water
containing fibres descends into the water, the surface is clear and free from fibres and
other parts, as the fibres etc., that adhere to the cylinder have been removed from
the cylinder by means of scrapers, brushes, cloths or the like. All fibres and other
particles in the water that are not longer than the openings in the wire gauze, and
long fibres, whose position in the water is not parallel or about parallel with the said
surface, can consequently pass through the wire gauze and pass away with the water.
As the small superficial part passes through the water, it is covered by fibres, that
cannot pass through the openings of the wire gauze, whereby the possibility of
small fibres etc., passing through the surface is more and more reduced. The fibres
which settle on the superficial part at last form a filter through which only liquid and
dissolved matters can pass. From what has been stated it is clear that from the part
of the cylinder that is descending or has just descended into the water, water con-
taining fibre runs into the cylinder while only filtered or pure water passes through
the other part of the cylinder, being in the water. The water that passes away from
the filtering cylinders now in use is consequently not free from fibres if an exceedingly
fine wire gauze be not used, and if it be used the wire gauze is not durable and filters
very slowly.
This invention is founded on the above mentioned circumstance or way of working.
of the filtering cylinders and it relates to an arrangement, by means of which only the
water containing fibres and running into the cylinder, is retained and again led to the
outer surface of the cylinder in order to be refiltered, while only the water, which has
been filtered through the fibre settled on the cylinder, is allowed to pass away. By

page_text: can be employed,
such an arrangement coarser wire gauze than that hitherto used
so that the wire gauze has greater filtering power. is more durable and can be more
easily kept clean by irrigation. No variations in the nature of the product obtained
can occur by using the arrangement in question, as the filtering process is the same
as in the filtering cylinders before used, so that in cylinders provided with the
arrangement in question, as in cylinders hitherto used, vegetable mens and other
matters extracted from the wood are carried away by the water, in consequence
of the velocity with which the water runs through the filtering layer on account
of the difference in height of the water surfaces outside and inside the cylinder, the
fibre being thus washed by the water and becoming purer and better than in the
clearing basins sometimes used.
In the accompanying drawings,—
Figure 1 is a vertical, longitudinal, axial section of a filtering or straining apparatus
embodying my improvements.
Figure 2 is a plan of the same.
Figure 3 is an end elevation looking at the left hand side of Figure 1.
Figure 4 is a transverse vertical section of the filtering cylinder detached.
This
In a tank or liquid holder 5, is rotatably mounted the filtering cylinder 1.
cylinder has a foraminous or apertured peripheral surface, which is covered with wire
gauze. The ends of the cylinder 1 are open, but in each open end is an annular end-
piece, or track, 2, which bears on two pairs of supporting rollers or wheels 3, fixed on
shafts which extend through the cylinder and have bearings on the tank 5. One
pair of wheels merely provides rolling bearings for the cylinder, but the other pain,
inounted on the shaft 4, serve as drivers for the cylinder, the said shaft having a
pulley on its outer end to receive a belt for driving from any source of power. The
annular end pieces 2 fit snugly up to the ends of the tank 5.
Inside the cylinder 1 and extending through it longitudinally is a trough 6, which
and 2-and is connected at
is closed at one end-the right hand end in Figures
the other end with a suitable pump 7, driven by means of a pulley for example.
The waste water flows into the tank 5 through a spout or channel 14, entering the
tank 5 outside a curved partition or deflector 15 (Figures 2 and 3) which passes down
under and partly around the cylinder 1 and compels the water entering the tank
to pass under the cylinder and up to the opposite, or rear side thereof, before it can
reach and enter the cylinder through its foraminous periphery.
Inside the cylinder is a quadrant-shaped receiver 11 (Figures 1 and 4) formed by
an upright plate 8 a horizontal plate 9, fixed to the trough 6, and end plates 10.
This receiver fits close to the periphery of the cylinder and is, of course, normally
stationary, while the cylinder rotates in the direction of the arrow in Figure 4.
Within the receiver 11, and extending lengthwise thereof, is an overflow plate 21,
over which the water accumulated in the receiver flows into the trough 6.
It will be noted that the quadrant-shaped receiver 11 includes the upper, rear
quadrant of the cylinder, and that the surface liquid flowing into the cylinder
from the tank at the back will enter this receiver 11, overflow thence into the
trough 6, be drawn out by the pump 7, and forced thence through the pipe 12,
to a spout 13, from which it flows into the spout 14, and thence back into the
tank 5 for re-straining or filtering. In Figure 2 the spout 13 can discharge into
the spout 14, and this is a convenient arrangement of the parts, but so long as
the water from the spout 13 is led back for re-filtering, it is not important how it is
returned. It may be carried to another filter for refiltering.
The operation of the apparatus is as follows:
The waste water, charged with fibre and other impurities, flows into the tank 5
from the spout 14, passes around and under the partition 15, thence up and over
the rear end of the partition, to that portion of the slowly rotating cylinder where
the receiver 11 is situated. At this point the smaller fibres and floating particles
carried by the water pass into the cylinder, for the reason that the cylinder is
not at this point coated with fibre and the like. As the cylinder continues to
rotate it gradually becomes coated externally with a filtering layer of fibres

page_text: which only allows water and matters in solution to pass and holds back all solid,
floating matter. This filtering layer is formed by the flow of water through the
immersed portion of the periphery of the cylinder. The filtered water entering the
cylinder flows off through the open ends of same to outlets 17. The layer of fibre is
removed from the cylinder in the ordinary manner by means of scrapers, rollers or the
like placed above the surface of the water in the tank 5 but not shown in the
drawing.
The fibres and light particles carried by the water entering at the inlet spout 14,
rise to, or near to the surface or water level at the rear end of the partition 15, and it
is this surface water, carrying most of the fibres, which enters the receiver 11 and is
pumped out for refiltration, while lower or deeper in the tank 5 the water contains
very little fibre and this water will be sufficiently well purified by passing through
the fibre coated, submerged portion of the cylinder.
In order that the apparatus may operate well, the bottom plate 9, of the
chamber 11, should be set deep enough below the normal level of the water in the
tank 5 to insure that a filtering layer of fibre shall form on the cylinder as it moves
down into the water on this side, while it is travelling from the normal water level of
the tank down to the level of the plate 9 and for this reason it is preferred to mount
the parts 6, 8, 9 and 10, which form the chamber 11, so that they can turn about the
axis of the cylinder 1, to a limitel extent, so that the quadrant-like receiver may be
slightly shifted within the cylinder. To effect this adjustment, an arm 18, fixed at
its lower end to the closed end of the trough 6, extends up and is coupled to a
horizontally arranged, screw-threaded operating rod 19, on which turns a wheel nut 20,
situated between stationary cheek pieces on the tank 5.
Obviously the cylinder 1 may be rotated by other means than that shown, and
the bottom plate 9 may be adjusted up or down by other meaus than that
last described.
The overflow plate 21 determines the depth of water in the receiver 11, and the
difference between the level of the water in the tank and in the said chamber 11.
Preferably the plate 21 is inclined, as shown, so that its upper edge is nearly over
the centre of the trough 6. This is in order to maintain the difference of level
between the water in the tank and receiver nearly constant even though the receiver
may be rocked to raise or lower the bottom plate 9.
The plate 8 of the chamber 11 need not extend much above the level of the water
in the tank 5, and this level must, of course, be above that of the water in the
receiver 11. A sight hole 22, may be provided in the end plate 10 so that the
overflow plate 21 may be inspected.
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:-.
1. In straining or filtering apparatus for the purpose specified, the combination
with a tank having an inlet for the impure water, and a rotating straining cylinder
mounted in the said tank and projecting above the water level therein, of a normally
stationary receiver in the cylinder for the surface water in the tank, and means
for withdrawing the water from the said receiver for refiltration, substantially as
set forth.
2. In straining or filtering apparatus for the purpose specified, the combination
with a tank having an inlet for the impure water, and a rotating straining cylinder
mounted in the said tank and projecting above the water-level therein, of a normally
stationary receiver with an adjustable bottom in the cylinder for the surface water in
the tank, means for withdrawing the water from the said receiver for re-filtration,
and means for adjusting the bottom 9 of the said receiver with respect to the water
level in the tank, substantially as set forth.
3. In straining or filtering apparatus for the purpose specified, the combination
with a tank having an inlet for the impure water, and a rotating straining
cylinder mounted in the said tank and projecting above the water level therein,

page_text: of a normally stationary receiver in the cylinder for the surface water in the tank,
means for withdrawing the water from the said receiver having a trough 6 for
re-filtration, and means for rocking the trough 6 about its axis for shifting the
position of the said receiver within the cylinder, substantially as set forth.
4. In straining or filtering apparatus for the purpose specified, the combination
with a tank having an inlet for the impure water, and a rotating straining cylinder
mounted in the said tank and projecting above the water level therein, of a
normally stationary receiver in the cylinder for the surface water in the tank, means
for withdrawing the water from the said receiver for re-filtration, and the overflow
plate 21, in the said receiver to limit the depth of water therein, substantially as set
forth.
5. In straining or filtering apparatus for the purpose specified, the combination
with the tank, the straining cylinder rotatably mounted therein, the normally
stationary receiver therein for the surface water, and the means for withdrawing
the water from the said receiver for refiltration, of the inclined overflow plate 21,
the upper edge of which is situated substantially over the centre line of the
outlet trough of the receiver, whereby, in the different adjustments of the receiver,
the level of the water in the latter may be maintained at substantially the same
distance below the level of the water in the tank, substantially as set forth.
6. In straining or filtering apparatus for the purpose described, the combination
with the tank, having an inlet. for the water to be filtered, and an outlet for the
filtered water, of the filtering cylinder rotatably mounted in the said tank, a normally
stationary receiver 11, within the said cylinder and adapted to receive the surface
water froin the tank when it passes into the cylinder-the said receiver comprising a
trough 6, upright plate 8, bottom plate 9, and end plates 10-a pump for withdrawing
the water from said receiver, and the overflow plate in the receiver, substantially as
set forth.
ليمه
C
1
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.