Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to an injector apparatus and
in particular to an injector for use in a flotation apparatus.
In a typical flotation apparatus, it is necessary to design
the in~ector so that it is capabla of raceiving and aerating a
large quantity of fluid to provide a good distrlbution of
aerated suspension when the fluid is dischargad into the
flotation tank. However, in conventional *lotation apparatus',
the in;ectors do not sol~e this requirement adequately.
Accordingly, there is a need for an improved injector for use in
a flotation apparatus.
It is an object of the present invention to obviate or
mitigate the above disadvantage.
According to the present invention there is provided an
injector for use in a flotation apparatus comprising:
a conduit means having an inlet for receiving a fluid flow
and an outlet positioned in said flotation apparatus for
discharging said flow therein;
an air supply means for supplying air into said conduit
means to aerate said fluid; and
a baffle disposed in said conduit means upstream from said
air supply means, said baffle churning said fluid prior to being
aerated to ensure sufficient bubble generation in said fluid.
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Pref~rably, the conduit means is a cylindrical feed pipe
including a substantially vertical section extending into the
flotation apparatus and the baffle comprises a cylindrical plate
having a plurality of bores of circular cross-section provided
therethrough. It is also preferred that the bores are
symmetrically distributed on the plate.
Preferably, the air supply means comprises an air feed line
connected at one end to an air supply and connected at the other
end to the feed pipe via air intake slots formed in the feed
pipe. It is also preferred that the air intake slots are
positioned downstream from the baffle a distance between one-
eighth to one-half the diameter of the feed pipe.
It is also preferred that the feed pipe has a diameter of at
least 160mm and that the langth thereof extending from the
baffle to the outlet is three to five times its diameter at the -~
air intake slots location.
The provision of the baffle in the feed pipa upstream from
the air supply means ensures that the fluid is sufficiently
churned prior to being asrated, thereby enhancing bubble
generation in the fluid and improving the flotation and
distribution of solid matter in the fluid when supplied to the
flotation apparatus.
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Embodiments of the present invention wi:Ll now be described
by way of example only with reference to -the accompanying
drawings in which:
Figure 1 is a sectional view of an injector used in a
flotation apparatus;
Figure 2 is a view of a portion of the device illustrated in
Figure 1 taken along line 2-2; and
Figure 3 ls a sectional view of another injector used in a
flotation apparatus.
Referring to Figures 1 and 2, an injector 10 is shown for
use in a flo-tation apparatus 12. The in~ector includes a
cylindrical feed pipe 14 having an inlet 16 at one end for
receiving a fluid containing solid matter therein and preferably
having a diameter of at least 160mm. The feed pipe 1~ is curved
and terminates in a substantially vertical section 18 extending
into a flotation tank 20. An outlet 22 forming a radial diffuser
24 is located at the other end of the feed pipe 14 and provides a
substantially horizontal fluid discharge path for the fluid into
the flotation tank 20.
A cylindrical baffle 26 is disposed in the vertical section
18 of the feed pipe 14 above the flo-tation tank 20. Tha baffle
26 is provided with a plurality of bores 28 of circular cross-
section, the bores 28 being symmetrically and radially disposed
about the centre of the baffle.
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Air intake slots 30 are formed in the vertical section 18 of
the feed pipe 14 downstream from the baffle 26 and receive air
from an air supply (not shown~ via an air feed line 32. The air
intake slots 30 are preferably positioned a Idistance A ranging
from about one-eighth to one-half the diameter D of the feed pipe
14 downstream from the baffle 26. Chokes 34 are provided on the
air feed line 32 to limit the amount of air supplied to the air
intake slots 32 and hence, effect air regulation of the fluid.
The length B of the vertical section 18 extending from the baffle
26 to the outlet 22 is preferably two and one-half to four times
the diame-ter D of the feed pipe 14 at the location of the air
intaka slots 30.
A second baffle 36 having a diameter E equal to
approximately one and three-quarters times the diameter D of the
feed pipe 14 is positioned at the bottom of the radial diffuser.
The outer ends 38 of the diffuser 24 extend radially outwardly to
form a cylindrical discharge outlet having a diamster F
preferably equal to two and a one-half times the diameter D.
In operation, the inlet 16 is supplied with the fluid having
solid matter therein that is to be aerated and fed to the
flotation apparatus 12 by way of the feed pipe 14. The fluid is
forced through the feed pipe 14 into the vertical section 18
wherein it flows against the baffle 26. The baffle 26 regulates
the flow of the fluid in the feed pipe 14 and effects proper
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churning thereof due to the symmatrical bores 28. The air supply
(not shown) supplies air into the feed pipe L4 downstream from
the baffle 26 via the air feed line 32 and a:ir intake slots 34.
Thus, the fluid is aerated before being conveyed to the outlet
22. At the outlet, the fluid flows against the lower baffle 36
and is further churned before being dischar~ed via outlets 38 of
the radial diffuser 24 into the flotation tank 20.
Since the fluid is well churned by the baffle 26 and since
the air intake slots 30 are provided proximally downstream
therefrom, the injector 10 ensures that the fluid is sufficiently
aerated prior to being supplied to the flotation apparatus to
enhance bubble generation in the fluid. This results in improved
flotation and distribution of the solid matter in the fluid when
the fluid is discharged into the flotation tank 20.
Referring to Figure 3, another embodiment of the in~ector
10' is shown. In this figure, like reference numerals will be
used to indicate like components with a ' added for clarity. The
vertical section 18' of the feed pipe 14' extending from the air
intake slots 30' to the outlet 22' is divided into upper and
lower portions 40 and 42, each portion being substantially equal
in length. The portion 40 is circular in cross-section having a
diameter D' and includes the baf~le 26' and the air intake slots
30' which are positioned and function in ths same manner as the
previous embodiment. The lower portion 42, however, is conical
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in shape having a steadily increasing diameter in a direction
towards the radial diffuser 2~'. The conical dimension of the
lower portion A2 enhances churning of the fluid prior to being
discharged into the flotation tank 20', thereby removing the need
for the lower baffle 36.
Although the present device has baan described using a
baffle having bores of circular cross-section, it should be
apparent that various numbers of differently shaped and sized
bores can be provided through the baffle 26.
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