Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to a separating or decanting device for
separating substances from a liquid to be puri~ied, typically oily materials
from water.
Various devices have been proposed to do this. United Kingdom
Patent 308,752 provides an outlet in the ~ront part of such a separator ~or
separating impurities from a liquid. Ihis patent also describes a separator
including an inclined plate and brake plates provided in the inlet part of
the separator so situated that heavier substances in the liquid sink to the
bottom of the separator under the influence of gravity, and can then be
discharged from the inlet part.
Similarly, United States Patent 2,613,811 provides a separator
for two liquids in which the heavy liquid is separated in a separator, and
then transmitted further through a drain provided underneath the separator.
The light liquid is discharged from the separator inlet cham~er.
Also in Canadian application 174,551 (now Canadian Patent
1,007,174) is described a separator comprising a tank with a separator
including at least two parallel inclined plates, separated apart. The
outlet for separated li~ht liquid, such as oil, is located at the upper end
of the tank. An overflow is placed between the outlet for purified liquid
and the separator. A space is also provided, bounded by the front wall of
the tank and the ~irst plate of the separator, into which the incoming
liquid is ~ed through the inlet to the separator, in order to eliminate
turbulence in the liquid be~ore it enters into the separator.
A11 of these separator devices suffer from the disadvantage that,
in particular, they are not able to discharge, pre~erably separately, sub-
stances that either have separated from the liquid be~ore it enters the
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separator, or that can be separated quite easily from the liquid when it
enters the separator.
A separator has been described, in United Kingdom Patent 1,329,~75,
which goes some way to alleviating this problem. A two-stage decanter is used,
in which in a first stage the oil-water mixture is heated. Easily-removable
oil particles are separated, and rise upwardly to a gathering area. The
remaining mixture stream is then led downwardly into a counter flow plate
separator, in which the separated oil travels upwardly against the downward
flow of the liquid. The separated oil collects into the same gathering area.
However this apparatus has two serious disadvantages: it requires a com-
paratively large space being very bulky, and, due to the counter-current flow
system used together with a comparatively short plate length does not reach a
high level of separating efficiency.
This invention seeks to overcome these problems, and to provide an
efficient, compact, separator.
Thus, this invention pxovides for a separating device for separating
substances from a liquid to be purified, said separating device comprising:
a tank having a bottom, and substantially vertical outer walls;
a substantially vertical inner dividing wall in the upper portion of
the tank, extending from a point below normal liquid level to a point above
normal liquid level, and dividing the upper portion of the tank into a first
and a second liquid containing space;
an inlet in the outer wall o~ the tank, ~or the liquid to be
purified, into the first liquid containing space;
a separator in the tank comprising at least two parallel inclined
plates spaced from each other, one of the inclined plates comprising a down-
ward extension of the inner dividing wall dividing the lower portion o~ the
tank, and providing an under flow connecting the first liquid con-taining space
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with the separator~ the inclined plates being so spaced and aligned that the
separator extends beneath the second liquid containing space;
a first outlet from the second liquid containing space in the tank
for the purified liquid;
an overflow between the second liquid containing space and the first
outlet;
a second outlet from the second liquid containing space for sepa-
rated light substances, the second outlet being at a point higher than the
level of the overflowj
a space for eliminatin~ substantially turbulence of the liquid to be
purified before entering the separator comprising the lower portion of the
first space, being bounded by the outer walls of the tank, the inner dividing
wall, and the inclined separator plate comprising the downward extensio.n of
the inner dividing wall,
a third outlet from the first liguid containing space at a point
higher than the inlet, for substances lighter than the purified liquid.
~he invention will be further explained with reference to the
attached drawing. 1
Figure 1 is a separating device with a coalescing filter.
Figure 2 is a separating device as shown in Figure 1 wi-th a
packet of plates.
~ he separaking de~ice according to Figure 1 consi~ts o:~ a tank
with a front wall 1, a rear wall 2 and a bo-t-tom 3.
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In this tank a coalescer or separator L~ is provided with parallel
outer plates 5 and 6, of which plate 5 extends from a vertical partition 21
of -the tank and forms an angle ~ with -this partition and ends at some distance
above the bottom 3. Plate 6 of the separator L~ extends upwardly ~rom the
rear wall 2 or (not shown) from the bottom 3 of the tank, close to the wall
2, at the same angle ~ with the rear wall 2 as plate 5 with parti-tion 21 and
terminates a-t some distance from the upper side of the tank, but above the
' lower extremity of plate 5.
Between plate 6 of the separator L~ and the wall 2 of the tank there
is provided a vertical baffle 7 connected to the side walls of the tank and
extending from the upper side of the tank terminating at some distance from
the wall 6 of the separator 4. Between this baffle 7 and the wall 2 there is
provided a second baf'fle 8, which extends from plate 6 of the separator 1~ and
terminates at some distance under the upper side of the tank, but above the
lower extremity of baffle 7.
In the space 9 between the front wall 1 of the tank and the
partition 21 and plate 5 of the separator L~ opens a supply line 10 for -the
liquid to be purified, whereas the purified liquid is discharged through line'
11, which is in communication with the space bounded by wall 2, plate 6 and
baffle 8. To discharge the separated 1mpurities, such as oil, an outlet pipe
12 is provided. It is also possible to apply an adjustable ou-tlet pipe
(skimmer). For the discharge of a light liquid fraction 23 from space 9, a
discharge 22 is provided in a similar way.
Ihe liquid to be purified enters the device through line 10 and
flows -through space 9, in which turbulence is eliminated completely or for
the greater part and which is amply dimensioned in order to separate light
liquids 23, such as petrol and petroleum, and flows at the lower side into the
separator L~.
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The separation of the impurities that is more difficult, such as
oil, gathers a-t the upper part of the -tank and are discharged th~ough pipe 12.
The purified liquid flows f`rom the upper side of the separator 4 underneath
ba~fle 7 and over baffle 8, serving as an overflow, to line 11 ~here it is
discharged. Arrows show the paths of the liquids. If desired, dependent on
the material to be treated, it is possible to provide a coalescing filter 13
between the plates 5 and 6.
In figure 2, the parts corresponding to those of figure 1 are
provided with the same references. In this figure is indicated that in order
to increase the capacity, a packet consisting of spaced parallel plates 14
can be provided between the outer plates 5 and 6 of-the separator, in which
the number of plates 14 and their mutual dis-tance can be chosen in connection
with the required capacity of the oil separating device.
For the discharge of a heavier fraction 27 from both the space 9,
from the separator 4 and through the passages 26, and from the space past the
separator by means of` the~o~erflow 7 and 8, the bottom 25 of the tank is of
a recessed construction so that a collecting chamber 28 is formed.
The heavier fraction 27 collected in this collecting chamber 28 can
be discharged through outlet 24.
~he capacity and the power to separa-te of the device can be varied
by varying -the number of plates of the plate packet. In this way it is possible
to obtain devices with a capacity that varies for instance between 3 and
35 m3/h
The packet of plates comprises a number of` completely identical
parallel standard plates, in this way reducing the cost of the manufacture. It
is possible, as is known, to provide the walls with fnngers or the upper
extremities of the individual plates can be flanged or bent such that coale-
scence of the contaminated liquid drops is stimulated.
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The angle ~ bet~een the ou-ter plates of the oll separator and -the
front and rear walls of the tank is chosen such that the space required for
the oil separator is small, whereas the oil separation is good.
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It is self-evident that with separators, in which the very
light fraction is missing from the liquid to be puri~ied, but a heavier
fraction is present indeed, we can suffice with the separator with one
collecting chamber, but without enlarged "ante"-space.
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