Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1050441
For separating components suspended ln a carrier
liquid separation devices are known comprising, for instance,
an inclined assembly of superposed, and in particular corrugat-
ed, plates defining therebetween passages for the liquid to be
treated in which passages the separation path length for these
components is shorter, said components then being collected on
the plates and sliding along said plates towards one of the
extremities of the assembly.
The separation effect is dependent, inter alia, on
the particle size. When the particles are too small an insuf-
ficient separation will take place at a sensible flow rate. In
order to obtain a better separation of smaller particles, it
is, therefore, favourable to bring about particles growth
beforehand.
From the prior patent application No. 169,310 of
Pielkenrood-Vinitex B.~., filed April 24, 1973 (issued October
11, 1977 as Canadian Patent No. 1,018,902)apparatuses are known
for bringing about coalescence of particles suspended in a
liquid, in which this liquid is guided through one or more
substantially vertical channels, and the walls thereof wlll
bring about a transverse velocity gradient in the liquid, the
! consequence thereof being that particles with different velo- -
cities will overtake one another so that the agglomeration
probability will be increased. Such auxiliary apparatuses have
appeared to be very effective, but a disadvantage is that they
need space so that, in particular in e~isting separation de-
, vices, the provision thereof may be objectionable.
The invention provides a separation device of the
` kind mentioned above, which is provided with such a coalescence
apparatus which does not require additional space.
The separation device according to the invention
$~ comprises a separation assembly which is positioned at a slope
in a basin and is defined at its upper side by an oblique wall,
, I
'
'
. -, , ' . ": .,. ,', , : . .. : , .. , '
10S04kl
which basiP is, furthermore, subdivided i~to two chambers by
means of a partition, the lower side of which joins said oblique
wall, which device is characterized by an assembly of plates
arranged in the triangular space between this oblique wall and
this partition, substantially vertical passages being de~ined
between said plates in which the coalescence mentioned above
can take place These plates can have various shapes, and
particularly define coalescence channels in which the liquid
is allowed to flow alternately upwards and downwards. In par-
ticular means can be provided for controlling the velocity
gradient in at least a part of these passages.
The invention will be elucidated below by reference
to a drawing, showing in:
Fig~ 1 a schematic cross-section of a device accord-
ing to the invention;
Fig~ 2 s partial cross-section on line II - II of
Fig. 1 of a special embodiment of 'this device;
Fig. 3 a partial cross-section corresponding to Figo
2 of another embodiment; and
Fig. 4 a partial cross-section corresponding to
Fig. 1 of still another embodiment.
The sep~rator shown in Figo 1 comprises a basin 1
~hich is, by means of a partition 2, divided into two chambers
3 and 4, an overflow weir 5 being arranged in the chamber 3
I allowing the lighter components floating on the liquid in the
I chamber 3 to flow off towards a discharge duct 6. In the chamber3 and on the oblique wall 7 of the basin l a separation assembly
8 of the usual kind, not shown in detail, is provided, said
assembly comprising a plurality of parallel plates, and being
defined at its upper side by an oblique wall 9. The oblique
plates of this assembly which, in particular, may be corrugated,
define separation passages communicating at the higher end with
--2--
1, . , .: .
lOS~)4~
the chamber 3, and, at the lower end, with the cha~ber 4, the
latter chamber connecting at its lower side with a collecting
space 10 for s~dimentating components.
The oblique upper wall 9 of this assembly defines,
together with the partition 2, a triangular part 11 of the
chamber 3. In the lower part of this space 11 a supply tube
12 is provided, extending across the whole width of this space,
which tube is provided with a slot or with separate openings `-~
through which the liquid supplied by this tube can be directed
into the space 11.
In the space 11 mutually parallel plates 13 are
arrangedO The liquid emerging from the tube 12 flows through
the passages 14 between these plates 13 upwards, and because o~
the friction against these plates a transverse velocity gradient
will be generated in the liquid so that, as a consequence of the
velocity differences thus generated, the particles suspended in
the liquid will overtake one another and can agglomerateO Since
the flow cross-section in the passages 14 gradually increases
upwardly, the flow velocity will gradually decrease. This is
~¦ 20 favourable as at a gradual particle growth also the risk will
increase that the particles will b~ disrupted again by shearing
forces between adjacent liquid layers. With a decreasing flow
velocity this risk decrease~ accordingly. Moreover, at a lower
velocity, the residence time in the part in question will in-
~ crease accordingly which, at the lower velocity gradient, is
J favourable.
The plates 13 may, in particular, be corrugated as
shown in Fig. 20 The corrugations of adjacent plates are, in
the case shown, in phase opposition so that also in the flow
~; 30 direction an alternating velocity gradient is produced which will
.,~ .
l~ promote the coalescence of particles as well. When alternating
- .
,1 ': . , .
.... . .... . .. . . .
~0509~4~
plates are shifted by about half a wave length, the plates are
brought in phase, and a different velocity gradient distribu- ;
tion will be obtained. In this respect reference is made to
the prior patent application NoO 169 3100
Fig. 3 shows another arrangement in which a part of
the plates 13' ext~nds as far as the oblique wall 9 but not as
high as the normal liquid level in the space 11, and the remain-
ing plates 13" extend upwards beyond the liquid level but remain
at some distance from the wall 9. The intermediate passages 14
constitute in this manner an alternately upward and downwa~ flow
path for the liquidO In the present case the liquid supply
tak0s place between the central plates 13', and the liquid is
then laterally subdivided into two branches, but it is, of course,
also possible to arrange the supply chamher at the lateral side
; The width of the passages 14 can be made larger towards t~e
outside, as described in the above-mentioned prior patent appli-
cation, so as to obtain an accordingly lower flow velocity, and
thus to reduce the risk of disruption of grown particles.
The plates 13' and 13" according to Fig. 3 are plane
but can also be made corrugated as shown in Fig. 2, It is also
possible to provide, in the manner described in the above-mentioned
prior patent application, auxiliary plates by means of which the
passages 14 are sub-divided into partial passages connected in
' parallel, in which the velocity gradient is accordingly higher,
which plates, in particular, can be made adjustable and can be
plane or corrugated. These plates can, moreover, be directed
1' either parallel to the plates 13 or, respectively, 13' and 13",
or transversely thereto~
Fig. 4 shows another embodiment in which, instead
of triangular plates according to Figo 3, plates 15' and 1~
are positioned substantially parallel to the partition 20 The
-4- -
10S044~
plates 15' extend as far as the oblique wall 9 but not as high
as the normal liquid level, and the plates 15' extend above the
liquid surface but remain at some distance from the wall 9. In
this manner passages 1~ are obtained again, forming alternately
upwardly and downwardly directed flow paths, and, in particular,
the width of these passages increase;. so as to reduce the flow
velocity accordingly. The last passage 16' is defined by a
.~, /5 "
plate ~B~ and~the oblique wall 9 and is, therefore, increasing
in widtho Also in this case additional plates can be arranged
~ in the passages for raising the velocity gradient.
The liquid flowing from the supply tube 11 or a
similar supply means flows through the different passages 14 or
16 in which, as a consequence of the transverse velocity gradient,
coalescence of suspended particles can occurO If these particles
are lighter than the carrier liquid, a part thereof will flotate
in the chamber 3, and the remaining particles will be entrained
by the liguid towards the intake of the assembly 80 In this
assembly a further separation of lighter components will take
! place, which, then, will flow back towards the chamber 3, and
~ the particles which are heavier than the carrier liquid will
flow off at the lower end from the assembly 8 and arrive in the
space 10. The clarified carrier liquid flows upwards into the
cha~ber 4 and is discharged from there in some suitable manner~
If necessary air (and in particular colloidally dis-
persed air) and/or other separation promoting agents can be
introduced into the lower end of the part 11 near the tube 12
or in this tub~o In the case of Figo 4 the plates 15" are shaped
I in such a manner that flotating components already separated
! in the passages 16, which will then float on the liquid, can flow
off towards the chamber 3~ In the case of the plates 13 and 13"
this can take place without additional measures since these plates
do not impede the remoYal of these floating components.
Within the scope of the invention many modifications
are poss~ble
' ' '' '.. . '..-'' .';. . .. '` ' '~' -, .: . ,'' `. ' . ,, . ' . .' :,'' ' . ., :
. ~ . - . . . . . , : . . .
